Session OPNTH

Opening Session on Thursday

Conference
9:00 AM — 9:05 AM KST
Local
May 27 Wed, 8:00 PM — 8:05 PM EDT

Best demo award

Sanghyo Kim, WCNC 2020 Demo Chair

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This talk does not have an abstract.

Session Chair

Kyunghan Lee (Seoul National University, Korea (South))

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Session KNTH-S1

Keynote

Conference
9:05 AM — 9:40 AM KST
Local
May 27 Wed, 8:05 PM — 8:40 PM EDT

A Fresh Look at an Old Problem: Network Utility Maximization - Convergence, Delay, and Complexity

Prof. Ness Shroff (Ohio State University)

8
Network Utility Maximization has been studied for resource allocation problems in communication networks for nearly two decades. Nonetheless, a major challenge that continues to remain open is how to develop a distributed congestion control and routing algorithm that can simultaneously provide utility optimality, fast convergence speed, and low delay. To address this challenge we take a fresh perspective on this old problem and develop a new algorithm that offers the fastest known convergence speed, vanishing utility optimality gap with finite queue length, and low routing complexity.

Our key contributions in this work are: i) the design of a new joint congestion control and routing algorithm based on a type of inexact Uzawa method in the Alternating Directional Method of Multiplier; ii) a new theoretical path to prove global and linear convergence rate without requiring the full rank assumption of the constraint matrix; and iii) a clear path for implementing the proposed method in a fully distributed fashion.

Session Chair

Kyunghan Lee (Seoul National University, Korea (South))

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Session KNTH-S2

Keynote

Conference
9:40 AM — 10:20 AM KST
Local
May 27 Wed, 8:40 PM — 9:20 PM EDT

Toward One Network Era: Integrated Terrestrial-Satellite Communication

Dr. Woo-Jin Byun (ETRI)

6
With the development of mobile communication technology, wireless data transmission speed is increasing, but the communication range is narrowing. In particular, millimeter wave 5G is expected to provide Gbps data services mainly in the hot spot area. Despite the development of mobile communication networks, there are still many coverage holes which mobile communication cannot provide data services. Covering all these shaded areas with a mobile communication network would be expensive. Moreover, people want to be provided with high-quality data services on airplanes and cruise ships. To this end, satellite and terrestrial communication networks are being integrated. Satellites have traditionally served to provide telecommunications services to disaster areas where terrestrial networks have collapsed. In addition, it has been providing broadcasting and communication services to marine areas and island-mountainous areas that do not reach the ground network. Terrestrial-Satellite communication network will be able to provide much higher quality
services.

In this talk, I would like to point out the development direction of terrestrial-satellite communication technology. In addition, the main technologies in the field of terrestrial-satellite communication required for the 5G + / 6G era will be explained.

Closing Remark for the Keynote Session with our Apology for the Disconnection

Kyunghan Lee

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This talk does not have an abstract.

Session Chair

Kyunghan Lee (Seoul National University, Korea (South))

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Session T1-S20

Massive MIMO 1

Conference
10:40 AM — 12:10 PM KST
Local
May 27 Wed, 9:40 PM — 11:10 PM EDT

On the Exact Outage Probability of 2 x 2 MIMO-MRC in Correlated Rician Fading

Prathapasinghe Dharmawansa (University of Moratuwa, Sri Lanka); Kumara Kahatapitiya (The University of Moratuwa, Sri Lanka); Saman Atapattu (University of Melbourne, Australia); Chintha Tellambura (University of Alberta, Canada)

4
This paper addresses a classical problem in random matrix theory-finding the distribution of the maximum eigenvalue of the correlated Wishart unitary ensemble. In particular, we derive a new exact expression for the cumulative distribution function (c.d.f.) of the maximum eigenvalue of a 2 × 2 correlated non-central Wishart matrix with rank-1 mean. By using this new result, we derive the exact outage probability of 2 × 2 multipleinput multiple-output maximum-ratio-combining (MIMO-MRC) in Rician fading with transmit correlation and a strong line-of-sight (LoS) component (rank-1 channel mean). We also show that the outage performance is affected by the relative alignment of the eigen-spaces of the mean and correlation matrices. In general, when the LoS path aligns with the least eigenvector of the correlation matrix, in the high transmit signal-to-noise ratio (SNR) regime, the outage gradually improves with the increasing correlation. Moreover, we show that as K (Rician factor) grows large, the outage event can be approximately characterized by the c.d.f. of a certain Gaussian random variable.

Optimal Relay and Antenna Selection in MIMO Cognitive Relay Network with Imperfect CSI

Priyanka Das (International Institute of Information Technology Bangalore, India); Rimalapudi Sarvendranath (IISc, India)

1
Cooperative relaying and multiple-input multiple-output (MIMO) transmission technologies exploit spatial diversity to improve the performance of the secondary users in an underlay cognitive radio network. We consider a MIMO cognitive relay network in which a secondary source and multiple relays have imperfect channel state information (CSI) of the interference links to the primary receiver. They sufficiently back-off their transmit powers on the basis of such CSI in order to adhere to an interference outage constraint. We propose an optimal relay and antenna selection scheme, which jointly selects a relay between the source and destination, a transmit antenna at the source, and a receive antenna at the destination to maximize the end-to-end signal-to-interference-plus-noise ratio (SINR) at the destination. To demonstrate the advantages of our proposed framework, we derive closed-form expression for the outage probability of the secondary network under non-identically distributed Rayleigh fading channels. We also derive an insightful expression for the asymptotic outage probability for high SINR and show that the diversity gain is lost when the interference power constraint is fixed. We then consider a practical scenario where the secondary users have only the mean channel power gains of the interference links. Under such CSI, we also derive an expression for the outage probability, and show that this can be used as a better performance/complexity tradeoff for high SINR.

MSE-Based Transceiver Optimization for Multicarrier MIMO SWIPT Systems

Xingxiang Peng, Peiran Wu and Minghua Xia (Sun Yat-sen University, China)

3
This paper studies the joint transceiver and power splitting (PS) ratio design for a multicarrier multiple-input and multiple-output (MIMO) simultaneous wireless information and power transfer (SWIPT) system. We present a unified optimization framework based on the minimization of a general mean square error (MSE) objective function, which includes the most commonly used criteria, such as arithmetic MSE, geometric MSE and maximum MSE minimizations. The optimal equalization matrices are first derived. Then we propose a two-layer scheme to jointly optimize the precoding matrices and the PS ratio. In the inner layer, a structural solution for the precoding matrices is derived based on the Schur-convexity/concavity of the objective function, with which the precoding optimization problems are solved by different closed-form power allocations. In the outer layer, we show that the optimized objective functions obtained by the inner-layer optimization are unimodal with respect to the PS ratio. This enables us to find the optimal PS ratio very efficiently by exploiting the Golden-section search. Simulations are provided to compare the achievable rate and error rate performances of the proposed transceiver schemes.

Low-Complexity Partially-Connected Hybrid Precoding for Massive MIMO Systems

Ming Zhu (Beijing University of Posts and Telecommunications, China); Gang Xie (Beijing University of Posts and Telecommunicaitions, China); Xiaolei Qi (Beijing University of Posts and Telecommunications, China)

2
Hybrid precoding is a promising solution for millimeter-wave (mmWave) massive multi-input multi-output (MIMO) systems. Most prior hybrid precoding algorithms have too high complexity to apply to actual systems. This paper presents a low-complexity partially-connected hybrid precoding algorithm. By directly utilizing phase angle information of the channel matrix, the algorithm at the analog precoding stage requires no complicated calculation and has the lowest complexity among the prior analog precoding algorithms known to the authors. Then the digital precoding is obtained through singular value decomposition (SVD) of the equivalent channel matrix. Simulation results show that the proposed design can achieve a satisfactory achievable rate and is also insensitive to imperfect channel state information (CSI) in mmWave channels.

Physical Layer Authentication for Non-coherent Massive SIMO-Based Industrial IoT Communications

Zhifang Gu (Southeast University, China); He Chen (The Chinese University of Hong Kong, Hong Kong); Pingping Xu (Southeast University, China); Yonghui Li and Branka Vucetic (University of Sydney, Australia)

2
Achieving ultra-reliable, low-latency and secure communications is essential for realizing the industrial Internet of Things (IIoT). Non-coherent massive multiple-input multipleoutput (MIMO) has recently been proposed as a promising methodology to fulfill ultra-reliable and low-latency requirements. In addition, physical layer authentication (PLA) technology is particularly suitable for IIoT communications thanks to its low-latency attribute. A PLA method for non-coherent massive single-input multiple-output (SIMO) IIoT communication systems is proposed in this paper. Specifically, we first determine the optimal embedding of the authentication information (tag) in the message information. We then optimize the power allocation between message and tag signal to characterize the trade-off between message and tag error performance. Numerical results show that the proposed PLA is more accurate then traditional methods adopting the uniform tag when the communication reliability remains at the same level. The proposed PLA method can be effectively applied to the non-coherent system.

Session Chair

Sunwoo Kim (Hanyang University, Korea (South))

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Session T1-S21

Coding Scheme 1

Conference
10:40 AM — 12:10 PM KST
Local
May 27 Wed, 9:40 PM — 11:10 PM EDT

An Unequal Coding Scheme for H.265 Video Transmission

Yekeng Huang, Meiying Ji, Jiachen Sun, Baodian Wei and Xiao Ma (Sun Yat-sen University, China)

0
In this paper, we propose a new multi-level unequal error protection (UEP) by superposition transmission (referred to as ML-UEP-by-ST) coding scheme, which provides finer error protection abilities than the unequal error protection by partial superposition transmission (referred to as UEP-by-PST) coding scheme. This new coding scheme is then applied to video transmission with the H.265 standard, where a video bitstream can be regarded as a series of one or more groups. Each group consists of either a coded video sequence (CVS) and parameter sets or a CVS only. In the ML-UEP-by-ST system, each group of an H.265 video bitstream is partitioned equally into three parts, the most important part (Part A), the less important part (Part B) and the least important part (Part C). Each of these three parts is encoded by the same low-density parity check (LDPC) code as standardized in the fifth generation mobile networks(5G). The transmission is then formed by three sections. The first transmission is coded Part A, the second transmission is the superposition of coded Part B and the interleaved version of coded Part A, and the third transmission is the superposition of coded Part C and the interleaved version of the second transmission. Simulation results show that the performance of our proposed UEP scheme is better than the traditional equal error protection (EEP) scheme and the two- level UEP-by-PST scheme over both additive white Gaussian noise (AWGN) channels and Rayleigh fading channels.

Symbol-Level Precoding Design for IRS-assisted MU-MISO Systems

Rang Liu, Hongyu Li, Ming Li and Qian Liu (Dalian University of Technology, China)

0
Intelligent reflecting surface (IRS) has emerged as a promising solution to enhance wireless communications in a low-cost and hardware-efficient fashion. Besides, symbol-level precoding (SLP) technique has attracted considerable attentions recently for its advantages in converting multiuser interference (MUI) into useful signal. In this paper, we investigate the symbollevel precoding in IRS-assisted multiuser multiple-input singleoutput (MU-MISO) systems to minimize the transmit power while guarantee the quality-of-service (QoS) of information transmissions. In order to solve this joint optimization problem, we develop an efficient iterative algorithm to decompose it into the precoder design and IRS design problems. To tackle the non-convex IRS design problem, we propose to use the log-sum-exp function to smooth the objective and map it into the Riemannian space, where the Riemannian conjugate gradient (RCG) algorithm is employed to solve this problem. Simulation results prove the significant performance improvement of IRS and illustrate the effectiveness of our proposed algorithm.

Protograph-based LDPC-Hadamard Codes

Pengwei Zhang and Francis C.M. Lau (The Hong Kong Polytechnic University, Hong Kong); Chiu Wing Sham (The University of Auckland, New Zealand)

0
We propose a novel type of ultimate-Shannon-limit- approaching codes, namely protograph-based low-density parity-check Hadamard (PLDPC-Hadamard) codes in this paper. We also propose a systematic way of analyzing such codes using Protograph EXtrinsic Information Transfer (PEXIT) charts. Using the analytical technique we have found a code of rate about 0.05 having a theoretical threshold of —1.42 dB. At a BER of 10-5, the gaps of our code to the Shannon capacity for R =3D 0.05 and to the ultimate Shannon limit are 0.25 dB and 0. 40 dB, respectively.

Stopping Criterion for NR LDPC Decoder based on PEXIT Chart Analysis

Taehyun Kim (Samsung Electronics, Korea (South)); Joo Sung Park (SAMSUNG Electronics, USA); Jun Heo (Korea University, Korea (South))

1
In this paper, an early stopping scheme is proposed for 5G new radio (NR) low-density parity-check (LDPC) decoders. The proposed scheme predicts that the LDPC decoder will not be able to correct errors and then stops the iterative decoding process before reaching the maximum number of iterations. When the number of parity checks unsatisfied at both the l-th and the (l−T)-th decoding iterations is larger than a threshold, the decoder with the proposed scheme predicts that the decoding of the codeword is failed at the last iteration. Protograph-based extrinsic information transfer (PEXIT) chart analysis is used to determine the threshold. Simulation results show that the LDPC decoder can correct errors with the lower average number of iterations by using both the conventional syndrome test and proposed scheme.

Decoding Orders and Power Allocation for Untrusted NOMA: A Secrecy Perspective

Sapna Thapar (Indian Institute of Technology Jammu, India); Deepak Mishra (University of New South Wales (UNSW) Sydney, Australia); Ravikant Saini (Indian Institute of Technology Jammu, India)

1
The amalgamation of non-orthogonal multiple access (NOMA) and physical layer security is a significant research interest for providing spectrally-efficient secure fifth-generation networks. Observing the secrecy issue among multiplexed NOMA users, which is stemmed from successive interference cancellation based decoding at receivers, we focus on safeguarding untrusted NOMA. Considering the problem of each user's privacy from each other, the appropriate secure decoding order and power allocation (PA) for users are investigated. Specifically, a decoding order strategy is proposed which is efficient in providing positive secrecy at all NOMA users. An algorithm is also provided through which all the feasible secure decoding orders in accordance with the proposed decoding order strategy can be obtained. Further, in order to maximize the sum secrecy rate of the system, the joint solution of decoding order and PA is obtained numerically. Also, a sub-optimal decoding order solution is proposed. Lastly, numerical results present useful insights on the impact of key system parameters and demonstrate that average secrecy rate performance gain of about 27 dB is obtained by the jointly optimized solution over different relevant schemes.

Session Chair

Namyoon Lee (POSTECH, Korea (South))

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Session T1-S22

Performance Analysis 1

Conference
10:40 AM — 12:10 PM KST
Local
May 27 Wed, 9:40 PM — 11:10 PM EDT

Performance Analysis of Distributed Beamforming With Random Phase Offsets

Justin Kong and Fikadu Dagefu (US Army Research Laboratory, USA); Brian Sadler (Army Research Laboratory, USA)

0
In this paper, we investigate a wireless network where multiple distributed transmitters adjust the phases of their signals so that they can be constructively added at an intended receiver (client). Unlike conventional beamforming with co-located and phase-synchronized antennas, geographically separated transmitters may have phase offsets induced by individual local carrier oscillators, that pose a challenge for coherent distributed beamforming. This is especially true for transmitters that are far apart, when distributed clock synchronization protocols may be more difficult to implement. There may also be a desired spatial repulsion among the positions of the transmitters in order to mitigate mutual coupling effects and extend the coverage region. In this regard, we analyze the performance of distributed beamforming with phase offsets by modeling the spatial distribution of the transmitters as a ,β-Ginibre point process that models the repulsive behavior. We consider two transmission strategies: (i) Transmitter selection in which the client chooses the transmitter providing the highest received power at the client, and (ii) Coherent beamforming in which multiple transmitters simultaneously send their signals to the client. From numerical simulations, we examine the impact of the phase offsets on the performance and confirm the accuracy of our analysis. It is shown that even with significant phase offset errors, employing coherent beamforming can be an effective strategy.

Performance of Raptor Codes on the BIAWGN Channel in the Presence of SNR Mismatch

Amrit Kharel (Qualcomm Inc., USA); Hussein Fadhel (University of Mississippi, USA); Lei Cao (The University of Mississippi, USA)

0
Accurate estimation of the channel signal to noise ratio (SNR) is essential for belief propagation (BP) decoding to operate optimally. Incorrect estimation of the channel SNR is known as SNR mismatch and can lead to serious degradation in BP decoding performance especially when a code is operating near its decoding threshold. We analyze the asymptotic performance of Raptor codes under SNR mismatch on the binary input additive white Gaussian noise (BIAWGN) channel using discretized density evolution (DDE). We provide the decoding thresholds of Raptor codes for a wide range of SNR mismatch values. Our results show that overestimation of channel SNR is slightly more detrimental than underestimation for lower levels of SNR mismatch, while, underestimation becomes more detrimental as the mismatch increases. Finally, we use DDE-based optimization to design SNR mismatch tolerant output degree distributions.

On Age and Value of Information in Status Update Systems

Peng Zou, Omur Ozel and Suresh Subramaniam (George Washington University, USA)

1
Motivated by the inherent value of packets arising in many cyber-physical applications (e.g., due to precision of the information content or an alarm message), we consider status update systems with update packets carrying values as well as their generation time stamps. Once generated, a status update packet has a random initial value and a deterministic deadline after which it is not useful (ultimate staleness). In our model, value of a packet decreases in time (even after reception) starting from its generation to ultimate staleness when it vanishes. The value of information (VoI) at the receiver is additive in that the VoI is the sum of the current values of all packets held by the receiver. We investigate various queuing disciplines under potential dependence between value and service time and provide closed form expressions for average VoI at the receiver. Numerical results illustrate the average VoI for different scenarios and the contrast between average age of information (AoI) and average VoI.

A Low-Complexity Algorithm for Cell Identity Detection in NB-IoT Physical Layer

Hung-Ying Chang, Jian-Bin Chang and Chao-Yu Chen (National Cheng Kung University, Taiwan)

0
Narrowband internet of things (NB-IoT) is a new cellular technology introduced by the 3rd generation partnership project (3GPP) for the purpose of massive connections. NB- IoT devices are expected to have low cost and low power. This paper proposes a new low-complexity algorithm for cell identity detection based on the property of the synchronization sequences. A two-stage grouping algorithm is presented to divide all the synchronization sequences into groups by utilizing the property of Zadoff-Chu sequences. Therefore, the number of operations are reduced and hence the computational complexity is decreased. The simulation results show that the proposed grouping method can achieve 70 percent reduction with slight performance loss.

A Novel Coordinated Multi-point Downlink Transmission Scheme for Ultra-dense Networks

Sudarshan Mukherjee (Indian Institute of Technology Guwahati, India); Dongsun Kim, Hewon Cho and Jemin Lee (Daegu Gyeongbuk Institute of Science and Technology (DGIST), Korea (South))

1
In this paper, we propose a novel coordinated multi-point (CoMP) downlink transmission strategy for the ultra-dense network (UDN) environment. In this proposed CoMP transmission scheme, we exploit the average received link power (ARLP) of the base stations (BSs) with respect to the ARLP of the strongest BS to a typical user, to dynamically adjust the number of cooperating BSs serving that user in the network. This allows us to effectively manage the inter-cell interference in the UDN regime. Our numerical results and simulations show that the proposed scheme can out-perform the existing fixed number of BS based CoMP transmission scheme in the high BS density scenario.

Session Chair

Taesoo Kwon (Seoul National University of Science and Technology, Korea (South))

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Session T2-S7

Scheduling

Conference
10:40 AM — 12:10 PM KST
Local
May 27 Wed, 9:40 PM — 11:10 PM EDT

Co-Optimizing Performance and Fairness Using Weighted PF Scheduling and IAB-aware Flow Control

Yingjie Zhang (University of California, Davis, USA); Vishwanath Ramamurthi (Verizon Wireless, USA); Zhiyi Huang and Dipak Ghosal (University of California, Davis, USA)

0
In 5G networks, wide-band mmWave can be used to provide extreme data rates to user equipments (UEs). However, since mmWave is coverage limited, it necessitates dense placement of base stations, which in turn can significantly increase the fiber deployment cost. One solution being considered is to replace fibers with Integrated Access and Backhaul (IAB) network, where a part of the wireless spectrum is used for connecting base stations. In an asymmetric IAB network, standard proportional fair scheduling algorithm (PF) fails to distribute resources among UEs fairly. We propose a new weighted proportional fair (WPF) scheduling algorithm to improve the fairness of UE's achieved throughput in an IAB network. Also to mitigate congestion in IAB nodes and improve system throughput, we propose an IAB- aware end-to-end flow control (I-EEFC) algorithm. Through detailed analyses for both symmetric and asymmetric network topologies, we show that our proposed combined scheduling and flow control algorithm (WPF + I-EEFC) improves both fairness and system throughput.

Scheduling Stochastic Real-Time Jobs in Unreliable Workers

Yu-Pin Hsu (National Taipei University, Taiwan); Yu-Chih Huang (National Chiao Tung University, Taiwan); Shin-Lin Shieh (National Taipei University, Taiwan)

0
We consider a distributed computing network consisting of a master and multiple workers processing tasks of different types. The master is running multiple applications. Each application stochastically generates real-time jobs with a strict job deadline, where each job is a collection of tasks of some types specified by the application. A real-time job is completed only when all its tasks are completed by the corresponding workers within the deadline. Moreover, we consider unreliable workers, whose processing speeds are uncertain. Because of the limited processing abilities of the workers, an algorithm for scheduling the jobs in the workers is needed to maximize the average number of completed jobs for each application. The scheduling problem is not only critical but also practical in distributed computing networks. In this paper, we develop two scheduling algorithms, namely, a feasibility-optimal scheduling algorithm and an approximate scheduling algorithm. The feasibility-optimal scheduling algorithm can fulfill the largest region of applications' requirements for the average number of completed jobs. However, the feasibility-optimal scheduling algorithm suffers from high computational complexity when the number of applications is large. To address the issue, the approximate scheduling algorithm is proposed with a guaranteed approximation ratio in the worst- case scenario. The approximate scheduling algorithm is also validated in the average-case scenario via computer simulations.

Exception of Dominant Interfering Beam: Low Complex Beam Scheduling in mmWave Networks

Eunkyung Kim (Electronics and Telecommunications Research Institute (ETRI), Korea (South)); Jeongho Kwak (DGIST, Korea (South)); Song Chong (KAIST, Korea (South))

2
We begin this paper by asking a simple question: All beams can be simultaneously activated thanks to the ignorable inter-beam interference and sharp beam shape in mmWave networks? This paper provides a counter-intuitive observation that interference between one-hop adjacent beams still significantly affects the network performance in mmWave networks. Leveraging this observation, we revisit an optimization of inter- beam scheduling problem in a network-wide mmWave system on top of a physical layer precoding technique and suggest practical and low-complex beam on/off scheduling and corresponding user scheduling algorithms. Finally, via simulations in a real mmWave network environment, we reveal that the proposed algorithm attains close to the performance of an optimal policy which has much higher computational complexity.

Average Age of Changed Information in the Internet of Things

Wenrui Lin (Sun Yat-Sen University, China); Xijun Wang (Sun Yat-sen University, China); Chao Xu (Northwest A&F University, China); Xinghua Sun and Xiang Chen (Sun Yat-sen University, China)

0
The freshness of status updates is imperative in mission-critical Internet of things (IoT) applications. Recently, Age of Information (AoI) has been proposed to measure the freshness of updates at the receiver. However, AoI only characterizes the freshness over time, but ignores the freshness in the content. In this paper, we introduce a new performance metric, Age of Changed Information (AoCI), which captures both the passage of time and the change of information content. Also, we examine the AoCI in a time-slotted status update system, where a sensor samples the physical process and transmits the update packets with a cost. We formulate a Markov Decision Process (MDP) to find the optimal updating policy that minimizes the weighted sum of the AoCI and the update cost. Particularly, in a special case that the physical process is modeled by a two-state discrete time Markov chain with equal transition probability, we show that the optimal policy is of threshold type with respect to the AoCI and derive the closed-form of the threshold. Finally, simulations are conducted to exhibit the performance of the threshold policy and its superiority over the zero-wait baseline policy.

Age of Information in Scheduled Wireless Relay Networks

Masoumeh Moradian (IPM, Iran); Aresh Dadlani (Nazarbayev University, Kazakhstan)

0
In this paper, we use the concept of Markovian jump linear systems in order to analyze the age of information (AoI) in discrete-time Markovian systems. This approach is in fact, the discrete-time counterpart of the stochastic hybrid system (SHS) model reported for analyzing AoI in continuous- time Markovian systems and thus, is referred to as the discrete-time SHS (DT-SHS) model. We then apply the DT-SHS model in two wireless relay network settings to analyze and optimize the AoI associated with the static link scheduling policies. The first relay network comprises of one relay and a direct link between source and destination, whereas the second setting has two relays and no direct link. Moreover, a static link scheduling policy schedules the links without any knowledge about the state of the network. Using results obtained through numerical simulations, we validate our analytical approach and show the effect of relays in AoI improvement.

Session Chair

Changhee Joo (Korea University, Korea)

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Session T3-S20

UAV (Unmanned Aerial Vehicle) 1

Conference
10:40 AM — 12:10 PM KST
Local
May 27 Wed, 9:40 PM — 11:10 PM EDT

UAV Trajectory and Sub-channel Assignment for UAV Based Wireless Networks

Nguyen Minh Dat (INRS-EMT & University of Quebec, Canada); Tai Manh Ho (École de Technologie Supérieure ÉTS, Canada); Long Bao Le (INRS, University of Quebec, Canada); Andre Girard (INRS-EMT and GERAD, Canada)

1
In this paper, we study the trajectory control and sub-channel assignment for unmanned aerial vehicles (UAVs) based wireless networks with wireless backhaul links. This design aims to optimize the max-min rate subject to data transmission demands of ground users (GUs). The underlying problem is a mixed integer nonlinear optimization problem because of the complicated relationship between the UAV-GU channel gains and the UAV's location in each time slot of the flight period. To tackle this problem, we employ the alternating optimization approach where we iteratively optimize the sub-channel assignment and UAV trajectory control until convergence. Moreover, the difference of convex functions (DC) optimization method and the arithmetic and geometric means (AM-GM) inequality are employed to convexify and solve the non-convex UAV trajectory sub-problem. Via extensive numerical studies, we illustrate the effective UAV's trajectory considering capacity-limited access and backhaul links and the non-negligible rate gain of the proposed design compared to a baseline employing the circular UAV trajectory around the center of service area and a heuristic algorithm for sub-channel assignment.

Flight Scheduling and Trajectory Control in UAV-Based Wireless Networks

Minh Tri Nguyen (EMT-INRS, University of Quebec, Canada); Long Bao Le (INRS, University of Quebec, Canada)

0
In this paper, we study the flight scheduling and trajectory control for UAV-based wireless networks. Particularly, we are interested in optimizing the flight time, trajectory, and power allocation for the UAVs serving the set of ground users. Our design allows UAVs to be dispatched at different time with different flight durations and trajectories to balance between communication and flying energy consumption considering UAVs' limited energy. To gain insights into the problem, we first study the single-UAV setting where we show mathematically that there exists a unique optimal flying duration to maximize the system throughput. Then, we investigate the double-UAV network scenario and we present an algorithm to optimize the trajectories, power allocation, user association for the UAVs. Via numerical studies, we show that the network throughput is maximized when the flying duration for each UAV is equal to its corresponding optimal flying duration in case of the single-UAV network.

Distributed Topology Control based on Swarm Intelligence In Unmanned Aerial Vehicles Networks

Qianyi Zhang, Gang Feng, Shuang Qin and Yao Sun (University of Electronic Science and Technology of China, China)

1
Unmanned aerial vehicles (UAVs) have shown enormous potential in both public and civil domains. Although multi-UAV systems can collaboratively accomplish missions efficiently, UAV network(UAVNET) design faces many challenging issues, such as high mobility, dynamic topology, power constraints, and varying quality of communication links. Topology control plays a key role for providing high network connectivity while conserving power in UAVNETs. In this paper, we propose a distributed topology control algorithm based on discrete particle swarm optimization with articulation points(AP-DPSO). To reduce signaling overhead and facilitate distributed control, we first identify a set of articulation points (APs) to partition the network into multiple segments. The local topology control problem for individual segments is formulated as a degree-constrained minimum spanning tree problem. Each node collects local topology information and adjusts its transmit power to minimize power consumption. We conduct simulation experiments to evaluate the performance of the proposed AP-DPSO algorithm. Numerical results show that AP-DPSO outperforms some known algorithms including LMST and LSP, in terms of network connectivity, average link length and network robustness for a dynamic UAVNET.

Trajectory Design and Generalization for UAV Enabled Networks:A Deep Reinforcement Learning Approach

Xuan Li (Beijing University Of Posts And Telecommunications, China); Qiang Wang (Beijing University of Posts and Telecommunications, China); Jie Liu (Beijing University of Post and Telecommunications, China); Wenqi Zhang (Beijing University of Posts and Telecommunications, China)

0
In this paper, an unmanned aerial vehicle (UAV) flies as a base station (BS) to provide wireless communication service. We propose two algorithms for designing the trajectory of the UAV and analyze the impact of different training approaches on transferring to new environments. When the UAV is used to track users that move along some specific paths, we propose a proximal policy optimization (PPO) -based algorithm to maximize the instantaneous sum rate (MSR-PPO). The UAV is modeled as a deep reinforcement learning (DRL) agent to learn how to move by interacting with the environment. When the UAV serves users along unknown paths for emergencies, we propose a random training proximal policy optimization (RT-PPO) algorithm which can transfer the pre-trained model to new tasks to achieve quick deployment. Unlike classical DRL algorithms that the agent is trained on the same task to learn its actions, RT-PPO randomizes the features of tasks to get the ability to transfer to new tasks. Numerical results reveal that MSR-PPO achieves a remarkable improvement and RT-PPO shows an effective generalization performance.

Performance Analysis of Temporal Correlation in Finite-Area UAV Networks with LoS/NLoS

Ruixin Jin (Beijing University of Post and Telecommunications, China); Liyun Yang (Beijing University of Posts and Telecommunications, China); Hongtao Zhang (Beijing University of Posts and Telecommunications & Key Lab of Universal Wireless Communications, Ministry of Education, China)

0
In the existing works, the finite-area distribution of Unmanned Aerial Vehicle (UAV) and the effects of LoS and NLoS in air-to-ground channels have not been modeled when analyzing the temporal correlation in UAV networks, which makes the current analyses unsuitable for the practical deployment in hotspots. This paper analyzes the temporal correlation by deriving the expression of the interference correlation and joint coverage probability in mobile UAV networks, where all UAVs move independently in a finite area and the channel fading is calculated based on air-to-ground channel model with LoS and NLoS. Specifically, the temporal correlation is measured by incorporating the fluctuations caused by probability variation of LoS and the reliable network topology caused by finite mobility into the wireless channels. Furthermore, the non-uniform distribution caused by random mobility of UAVs is considered over different time slots. The results show that the interference correlation decreases as the moving distance of UAVs increases, and the decreasing interference correlation offsets part of the decrease in joint coverage probability caused by increasing moving distance of UAVs.

Session Chair

Yao Sun (University of Electronic Science and Technology of China, China)

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Session T3-S21

Security and Privacy 1

Conference
10:40 AM — 12:10 PM KST
Local
May 27 Wed, 9:40 PM — 11:10 PM EDT

Bloom Filter Based Low-Latency Provenance Embedding Schemes in Wireless Networks

J Harshan, Amogh Vithalkar, Naman Jhunjhunwala, Manthan Kabra and Prafull Manav (Indian Institute of Technology Delhi, India); Yih-Chun Hu (University of Illinois at Urbana-Champaign, USA)

1
A number of applications in next-generation multi- hop networks impose low-latency requirements on data transmission thereby necessitating the underlying relays to introduce negligible delay when forwarding the packets. While traditional relaying techniques such as amplify-and-forward may help the packets to satisfy latency-constraints, such strategies do not facilitate the destination in determining security threats, if any, during the packet's journey. Inspired by the problem of relaying packets that have low-latency constraints, we revisit the design of provenance embedding algorithms to reduce delays on the packets and yet assist the destination in determining the provenance with no knowledge on the network topology. We propose a new class of provenance embedding techniques, referred to as double- edge (DE) embedding techniques, wherein a subset of the relay nodes in the path strategically skip the provenance embedding process to reduce the delays on the packets. Under the framework of DE embedding techniques, we propose a deterministic skipping strategy among the nodes such that the destination can recover the provenance of every packet. Using fixed-size bloom filters as tools to implement the double-edge embedding ideas, we propose upper bounds on the error-rates of the DE embedding technique as a function of the number of nodes in the network, number of hops, bloom filter size, and the number of hash functions used by each node. Subsequently, we demonstrate the efficacy of the DE embedding technique on a testbed of Digi XBee devices, and show that it outperforms competitive baselines both in terms of latency as well as error-rates.

Ergodic Secrecy Rate of K-user MISO Broadcast Channel with Improved Random Beamforming

Ye Fan, Xuewen Liao and Zhenzhen Gao (Xi'an Jiaotong University, China)

1
In this paper, we study the secrecy performance of multiple-input single-output (MISO) wiretap channel with random beamforming (RB), where the eavesdropper is equipped with multiple antennas. In traditional RB schemes, the transmitter utilizes only one antenna to emit information signal and adopts the rest antennas to produce a random beamforming vector for security. To make full use of the power resource and improve the secrecy performance, we propose a power-minimizing and signal-splitting random beamforming (PM-SSRB) scheme, where the random beamforming vector is generalized with arbitrary number of transmit antennas based on power-minimizing. To evaluate the secrecy performance of the proposed scheme, we analyze the ergodic secrecy rate and derive the closed-form expression of the ergodic rate of the MISO wiretap channel. Simulation results show that, compared with the traditional hybrid artificial fast-fading scheme (AFF) and artificial noise (AN) scheme, the proposed SSRB scheme and PM-SSRB scheme perform much better in terms of the ergodic secrecy rate in all power regimes. More importantly, when the eavesdropper has more antennas than the transmitter, our schemes always outperform the AFF and AN schemes. The PM-SSRB scheme is also shown to be superior to the secret-key AFF scheme.

A Secure Authentication Scheme for Remote Diagnosis and Maintenance in Internet of Vehicles

Ruhui Ma and Jin Cao (Xidian University, China); Dengguo Feng (State Key Laboratory of Cryptology, Beijing, China); Hui Li (Xidian University, China); Ben Niu (Institute of Information Engineering, Chinese Academy of Sciences, China); Fenghua Li (State Key Laboratory of Information Security, Institute of Information Engineering, CAS, China); Lihua Yin (Guangzhou University, China)

0
Due to the low latency and high speed of 5G networks, the Internet of Vehicles (IoV) under the 5G network has been rapidly developed and has broad application prospects. The Third Generation Partnership Project (3GPP) committee has taken remote diagnosis as one of the development cores of IoV. However, how to ensure the security of remote diagnosis and maintenance services is also a key point to ensure vehicle safety, which is directly related to the safety of vehicle passengers. In this paper, we propose a secure and efficient authentication scheme based on extended chebyshev chaotic maps for remote diagnosis and maintenance in IoVs. In the proposed scheme, to provide strong security, anyone, such as the vehicle owner or the employee of the Vehicle Service Centre (VSC), must enter the valid biometrics and password in order to enjoy or provide remote diagnosis and maintenance services, and the vehicle and the VSC should authenticate each other to ensure that they are legitimate. The security analysis and performance evaluation results show that the proposed scheme can provide robust security with ideal efficiency.

WiRE: Security Bootstrapping for Wireless Device-to-Device Communication

Yinrong Tao, Sheng Xiao and Bin Hao (Hunan University, China); Qingquan Zhang (University of Illinois, Urbana Champaign, USA); Ting Zhu (University of Maryland, Baltimore County, USA); Zhuo Chen (Office of Ecology Protection, Management and Construction Hunan Province, China)

0
Rapidly evolving wireless technologies enable devices to directly exchange information without infrastructural support. In these device-to-device (D2D) communication scenarios, it is often difficult to setup cryptographic keys to initialize the secure communication, especially when the D2D connections are mobile and dynamic. This paper proposes an application layer solution scheme to bootstrap secure communications using the inherent randomness in the wireless transmissions. The proposed scheme is lightweight, easy to deploy and compatible with many physical layer wireless technologies. This paper contains security analysis to the scheme and conducts experiments to demonstrate its practicality.

Utility-aware Exponential Mechanism for Personalized Differential Privacy

Ben Niu (Institute of Information Engineering, Chinese Academy of Sciences, China); Yahong Chen (Institute of Information Engineering, CAS & School of Cyber Security, UCAS, China); Boyang Wang (University of Cincinnati, USA); Jin Cao (Xidian University, China); Fenghua Li (Institute of Information Engineering, CAS & School of Cyber Security, UCAS, P.R. China)

0
Personalized Differential Privacy (PDP) was proposed to satisfy users' different privacy requirements. However, most of the existing PDP mechanisms may significantly destroy the utility of released statistical results. Differentially private statistical results with poor utility may mislead the data analysts, thus it may even decrease the acceptability of the technique used to protect data privacy. Therefore, in this paper, our goal is to pursue higher data utility while satisfying personalized differential privacy. To achieve this goal, we propose the Utility- aware Personalized Exponential Mechanism (UPEM) to effectively achieve PDP while pursuing better utility. UPEM distinguishes the different possible results with the same personalized score, which is used in Personalized Exponential Mechanism (PEM) [1]. PEM considers the personalized privacy budgets of changing elements to achieve PDP. Based on PEM, our UPEM further considers the quantitative changes of these changing tuples to enhance the utility. We confirm the effectiveness and efficiency of UPEM through extensive experiments.

Session Chair

J Harshan (Indian Institute of Technology Delhi, India)

Play Session Recording
Session T3-S22

Resource Management and Optimization 1

Conference
10:40 AM — 12:10 PM KST
Local
May 27 Wed, 9:40 PM — 11:10 PM EDT

QoS-Driven Stochastic Analysis for Heterogeneous Cognitive Radio Networks

Muyu Mei, Qinghai Yang and Meng Qin (Xidian University, China); Kyung Sup Kwak (Inha University, Korea (South)); Ramesh R. Rao (UCSD, USA)

1
The future 5G wireless network is largely driven by the increasing heavy traffic and spectrum scarcity. Cognitive Radio (CR) techniques provide a potential solution for improving the spectrum efficiency. In this paper, we study the stochastic framework for the CR networks, considering different quality of service (QoS) requirements. To analyze the performance of the CR network, we adopt a poisson point process (PPP) to capture the mobility and randomness of user location. A stochastic- network-calculus (SNC) based approach is proposed to model the wireless transmission and evaluate the network performance. In order to achieve the performance metrics of end-to-end (E2E) delay and backlog in the entire network, we propose a new conception named as effective service process (ESP) which is able to capture the QoS requirements of users. Furthermore, we evaluate the performance in the exponential domain, which can present the E2E analysis more directly. The simulation results verify the theoretical analysis and show that the performance in the CR networks can be derived perfectly with the proposed approach, considering the stochastic traffic arrival and designed service model in our schedule.

Joint User-Centric Clustering and Frequency Allocation in Ultra-Dense C-RAN

Qiang Liu, Sun Songlin and Hui Gao (Beijing University of Posts and Telecommunications, China)

3
This paper considers the downlink ultra-dense cloud radio access network (C-RAN), which employs multiple radio remote head (RRH) cooperation to guarantee the minimum achievable transmission rate for each user equipment (UE). However, due to the limited orthogonal frequency resources, it is difficult to achieve this goal. To maximize the coverage probability of the system, we focus on the joint user-centric clustering and frequency allocation problem. To reduce the computational complexity, this problem is split into two sub-problems: user- centric clustering and frequency allocation. Firstly, we propose a novel binary user-centric clustering strategy, which includes serving clusters and silent clusters. This strategy determines the acceptable combination of serving clusters and silent clusters to guarantee the minimum transmission rate for each UE and simplify the complexity of the subsequent frequency allocation. Then based on the generated clusters, a new graph generation method is proposed. The advantage of this graph is that we can allocate frequency resources by simply judging the relationship between the serving clusters in the graph without complicated calculations. Numerical simulation results show that the joint binary user-centric clustering and location-based frequency allocation scheme is superior to the benchmark solutions in terms of the coverage probability.

Trading Based Service-Oriented Spectrum-Aware RAN-Slicing Under Spectrum Sharing

Kajia Jiao and Xuanheng Li (Dalian University of Technology, China); Miao Pan (University of Houston, USA); Fan Jiang (Xian University of Posts and Telecommunications, China); Ming Li (Dalian University of Technology, China)

1
The fast development on emerging services makes our telecommunications networks witness two key problems. One is the flexibility to fulfill the diverse service requests and the other is the shortage on spectrum. Network slicing and spectrum sharing have been regarded as two prominent solutions, which, however, are barely jointly studied. When taking the shared spectrum into account, its unique feature of heterogeneity and uncertainty will bring new challenges for the slicing. In this paper, we propose a service-oriented spectrum-aware RAN-slicing trading (SSRT) scheme with a comprehensive consideration on both aspects. For the SSRT scheme, we jointly slice three kinds of resources, namely, time, spectrum (including both licensed one and shared one), and network facilities, according to the diverse traffic requests, which are classified into delay-tolerant (DT) ones and delay-sensitive (DS) ones, as well as the willing payments from different service providers (SPs). To achieve both inter-slice and intra-slice isolation, we construct a three-dimensional (3D) conflict graph and formulate the SSRT scheme into a mixed-integer nonlinear programming (MINLP) problem with a cross-layer spectrum-aware resource allocation and a hybrid transmission mode (including both single-hop and multi-hop). Since finding all the maximum independent sets (MIS) for the 3D conflict graph is an NP-hard problem, we further develop an iterative heuristic algorithm for the MIS determination.

Throughput Analysis in Cache-enabled Millimeter Wave HetNets with Access and Backhaul Integration

Chenwu Zhang, Hao Wu, Hancheng Lu and Jinxue Liu (University of Science and Technology of China, China)

3
Recently, a mmWave-based access and backhaul integration heterogeneous networks (HetNets) architecture (mAB- HetNets) has been envisioned to provide high wireless capacity. Since the access link and the backhaul link share the same mm- wave spectral resource, a large spectrum bandwidth is occupied by the backhaul link, which hinders the wireless access capacity improvement. To overcome the backhaul spectrum occupation problem and improve the network throughput in the existing mABHetNets, we introduce the cache at base stations (BSs). In detail, by caching popular files at small base stations (SBSs), mABHetNets can offload the backhaul link traffic and transfer the redundant backhaul spectrum to the access link to increase the network throughput. However, introducing cache in SBSs will also incur additional power consumption and reduce the transmission power, which can lower the network throughput. In this paper, we investigate spectrum partition between the access link and the backhaul link as well as cache allocation to improve the network throughput in mABHetNets. With the stochastic geometry tool, we develop an analytical framework to characterize cache-enabled mABHetNets and obtain the signal- to-interference-plus-noise ratio (SINR) distributions in line-of- sight (LoS) and non-line-of-sight (NLoS) paths. Then we utilize the SINR distribution to derive the average potential throughput (APT). Extensive numerical results show that introducing cache can bring up to 80% APT gain to the existing mABHetNets.

Jointly Optimizing Helpers Selection and Resource Allocation in D2D Mobile Edge Computing

Yang Li, Gaochao Xu and Jiaqi Ge (Jilin University, China); Peng Liu (Northeast Forestry University, China); Xiaodong Fu (Jilin University, China); Zhenjun Jin (Changchun University of Technology, China)

3
Device-to-Device (D2D) communication has attracted extensive researches because of its ability to reduce latency and improve the spectrum resource utilization. This paper studies a D2D Mobile Edge Computing (MEC) system which contains multiple busy smart devices (SDs) and multiple idle smart devices. To minimize the total energy consumption of the MEC system and satisfy the latency constraints of SDs, the computation intensive task of each busy SD can be partially offloaded to one or more idle SDs as helpers. Therefore, a joint optimization problem of helpers selection and communication and computation resources allocation is proposed. The problem is formulated as an integer- mixed non-convex optimization problem which is a NP-hard problem. We thus propose a two-phase iterative approach by jointly optimizing helpers selection and communication and computation resources allocation. In the first phase, we obtain the suboptimal helpers selection policy with convex optimization techniques and block coordinate descent method. In the second phase, the resource allocation strategy is achieved by applying block coordinate descent after obtaining the suboptimal helpers selection policy. The simulation results demonstrate that not only the proposed algorithm achieves fast convergence in both phases, but also the overall energy consumption is less than other benchmarks.

CIRNO: Leveraging Capacity Interference Relationship for Dense Networks Optimization

Srikant Manas Kala (IIT HYDERABAD, India); Vanlin Sathya (University of Chicago, USA); Winston K.G. Seah (Victoria University of Wellington, New Zealand); Bheemarjuna Reddy Tamma (IIT Hyderabad, India)

3
To meet the rising data-offloading demands, IEEE 802.11-based WiFi networks have undergone consistent den- sification. The unlicensed spectrum has also been harnessed through LTE-WiFi coexistence. However, in dense and ultra-dense networks (DNs/UDNs), the network capacity is even more adversely impacted by the endemic interference. Yet, the precise nature of Capacity Interference Relationship (CIR) in DNs/UDNs and LTE-WiFi coexistence remains to be studied. Densification also exacerbates the challenges to network optimization. The conventional approaches to simplify the complex SINR-Capacity constraints lead to high convergence times in DN/UDN optimization. We investigate the CIR in dense and ultra-dense WiFi (IEEE 802.11a) and LTE-WiFi (LTU/LAA) networks through real-time experiments. We then subject the empirical data to linear and polynomial regression to determine the nature of CIR and demonstrate that strong linear correlations may exist. We also study the impact of predictor variables, topology, and radio access technology on CIR. Most importantly, we propose CIRNO, a CIR-inspired network optimization approach, wherein the empirically determined CIR equation replaces the theoretically assumed SINR-Capacity constraints in optimization formulations. We evaluate CIRNO by implementing three recent works on optimization. We demonstrate the relevance of CIR and CIRNO in DNs/UDNs through a significant reduction in convergence times (by over 50%) while maintaining high accuracy (over 95%). To the best of our knowledge, this is the first work to statistically analyze CIR in DNs/UDNs and LTE-WiFi heterogeneous networks (HetNets) and to use CIR regression equations in network optimization.

Session Chair

Bheemarjuna Reddy Tamma (IIT Hyderabad, India)

Play Session Recording
Session T4-S10

Crowdsourcing and Incentive Mechanism

Conference
10:40 AM — 12:10 PM KST
Local
May 27 Wed, 9:40 PM — 11:10 PM EDT

Microscopic Traffic Monitoring and Data Collection Cloud Platform Based on Aerial Video

Guan-Wen Chen, Tzu-Chuan Yeh, Ching-Yu Liu and Tsì-Uí İk (National Chiao Tung University, Taiwan)

0
Real-time traffic video streaming, such as roadside surveillance and aerial video, has been widely used in traffic monitoring nowadays. However, most of the traditional traffic data collection methods lack mobility that can only collect macroscopic data. In this paper, an intelligent traffic monitoring system based on an open source cooperative platform called SAGE2 was developed. Based on the integrated big screen TV wall of SAGE2, a map-based aerial traffic video streaming management interface was designed. In the image pre-processing section, it provides functions such as lens distortion removal, top view projection transforms, and video stabilization; simulate video streaming to provide instant and long-term micro-flow data collection. Micro-traffic flow data provides high-resolution information both in time and space which can be used to analyze the driving behavior of individuals and the public. Combined with the lane level map, it can provide a variety of visual vehicle flow presentations, such as intersection traffic distribution that can also be used to develop an innovative application in the future.

Blockchain-Enabled Computing Resource Trading: A Deep Reinforcement Learning Approach

Zixuan Xie and Run Wu (Sun Yat-sen University, China); Miao Hu (Sun Yat-Sen University, China); Haibo Tian (Sun Yat Sen University, China)

1
Driven by the vision of the Internet of Things (IoT) under the fifth-generation (5G) wireless network, computing resource trading attracts numerous attention from both academia and industry. Prior works mainly focus on the design of auction mechanisms to implement pricing and resource allocation. However, it is still a challenging problem because of the following three aspects: 1) How to ensure that the auction mechanism runs fairly? An auction mechanism is vulnerable and questionable since the auctioneer may fail the orders matching operation or collude with a few peers. 2) It's hard to assign the computing resources of providers to customers and guarantee reasonable rewards for each participator. 3) How to make bidding strategies for each participator? Each participator has its willingness to sell/buy, which are time-variant and private. To address the above issues, we build a blockchain-enabled computing resource trading system that takes both pricing and bidding strategies into consideration, on which providers and customers can trade computing resources securely, safely and willingly. Next, we formulate a decision-making problem in the continuous double auction (CDA) to maximize their payoffs. Then, we propose a universal model-free Deep Reinforcement Learning (DRL) framework for both computing resource providers and customers. We conduct extensive experiments to evaluate the performance of our DRL framework. Simulation results show that our solution outperforms others in both static and dynamic scenarios. Our DRL framework can achieve higher rewards than others by at least 35%. Furthermore, the average trading price from our DRL framework is less volatile than that from the compared methods. The DRL framework promotes trading and brings larger trading quantities, thus resulting in higher social welfare by at least 25% than the compared schemes.

Rating-aware Pre-cache and Incentive Mechanism Design in Data Offloading

Yiting Luo and Fen Hou (University of Macau, Macao); Bin Lin (Dalian Maritime University, China); Guanghua Yang (Jinan University, China)

0
Pre-caching popular contents in advance at the network edge such as base stations is a promising method to improve the service quality by reducing the transmission cost and network congestion. In this paper, by jointly considering the mobile users' rating on different contents into the incentive mechanism design, we proposed a rating-aware incentive mechanism for efficiently selecting some BSs to pre-cache the popular contents. The proposed mechanism can achieve higher performance compared with other existing methods in terms of the social welfare. In specific, the proposed mechanism can improve the achieved social welfare by 11.75% and 9.97% compared with the mechanism of random caching and the caching based on bid price, respectively. In addition, the proposed mechanism satisfies the nice properties of individual rationality and truthfulness.

Incentive Mechanism Design for Mobile Data Rewards using Multi-Dimensional Contract

Zehui Xiong (Nanyang Technological University, Singapore); Wei Yang Bryan Lim (Nanyang Technological University & Alibaba Group, Singapore); Jiawen Kang and Dusit Niyato (Nanyang Technological University, Singapore); Ping Wang (York University, Canada); Chunyan Miao (Nanyang Technological University, Singapore)

1
Mobile data rewards is now leading a new economic trend in wireless networks, where the operators stimulate mobile users to view ads with data rewards and ask for corresponding payments from advertisers. Yet, due to the uncertain nature of users' preferences, it is always challenging for the advertiser to find the best choice of data rewards to attain an optimum balance between ad revenue and rewards spent. In this paper, we develop a general contract-theoretic framework to address the problem of data rewards design in a realistic asymmetric information scenario, where each user is associated with multi-dimensional private information. Specifically, we model the interplay between the advertiser and users by using a multi-dimensional contract design approach, and theoretically analyze optimal data rewarding schemes. To ensure global incentive compatibility, we convert the multi-dimensional contract problem into an equivalent one-dimensional contract problem. Necessary and sufficient conditions for an optimal and feasible contract are then derived to provide incentives for engagement of users in data rewarding scheme. We leverage numerical results to evaluate the performance of the designed multi-dimensional contract for data rewarding scheme.

VCG-QCP:A Reverse Pricing Mechanism Based on VCG and Quality All-pay for Collaborative Crowdsourcing

Lifei Hao, Bing Jia, Jingbin Liu, Baoqi Huang and Wuyungerile Li (Inner Mongolia University, China)

0
With the rapid development of the Internet and combined with outsourcing, a new paradigm - crowdsourcing which shines brilliantly as a new labor mode. However, the existing pricing strategies for crowdsourcing tasks have several undesirable problems, e.g., no universal pricing model, not meeting the multiple requirements of users, pricing rely too much on decision makers, etc., which bring an unreasonable allocation of task rewards so as to make the pricing results subjective and uncontrollable. Therefore, this paper proposes a reverse pricing mechanism based on VCG and quality all-pay for collaborative crowdsourcing (VCG-QCP). The actual crowdsourcing scenario is considered with VCG mechanism, and the concept of quality all-pay is introduced to evaluate the work quality of workers who might perform the task. Then a general reverse pricing model is established by mathematical modeling, and the pricing algorithm is designed based on this model. Simulations show that the proposed method can achieve higher algorithm efficiency, higher task completion quality, a reasonable balance of benefits between employers and workers, and ensuring the truthfulness of workers' bidding.

Session Chair

Won-Yong Shin (Yonsei University, Korea)

Play Session Recording
Session T4-S9

Recognition and Prediction

Conference
10:40 AM — 12:10 PM KST
Local
May 27 Wed, 9:40 PM — 11:10 PM EDT

Performance Evaluation of Driving Behavior Identification Models through CAN-BUS Data

Mozhgan Nasr Azadani and Azzedine Boukerche (University of Ottawa, Canada)

0
Modern cars can collect several hundreds of sensor data through the controller area network (CAN) bus technology that provides almost real-time information about the car, the surrounding environment, and the driver. These data can be later processed and analyzed to offer efficient solutions and insights for human behavior analysis and further applied in a variety of fields such as accident prevention, driver identification, driving models design, and vehicle energy consumption. By analyzing and identifying unique driving behavior, we can distinguish drivers, which can be helpful in driver profiling and security of the cars (anti-theft systems). In this paper, we evaluate the performance of data-driven end-to-end models designed for driving behavior identification. We present a critical analysis of the principles considered in designing the models. Moreover, various data-driven deep learning and machine learning models are implemented and the cross-validation results are presented employing the naturalistic driving dataset.

PathExtractor: A Path-Semantic extraction Algorithm for Mobility Prediction

Zhuang Su, Ying Wang and Zhengwei Lyu (Beijing University of Posts and Telecommunications, China)

0
In recent years, mobility prediction has attracted much attention. Prediction methods include two steps, extracting spatial-temporal features to convert the trajectory to location sequences and constructing a model to make further predictions. Traditional methods often define the location as grids or points of interest (POIs) in mining spatial-temporal features. But these methods may not perform well in prediction because of losing detailed information of trajectories. Thus, a novel location semantics is necessary to compress detailed trajectories. In this paper, a path semantics extraction method, PathExtractor was proposed to extract typical paths and build path sequences, which contains complete information of trajectories. Furthermore, to verify that path sequences can effectively express movement patterns, the prediction is performed by constructing a recurrent neural network model. Finally, in order to evaluate the application value of path semantics, path similarity is used as performance indicator, and experiments prove the accuracy of path prediction and geographical precision higher than others.

Detection of Suspicious Objects Concealed by Walking Pedestrians Using WiFi

Bao Zhou, Zuona Chen, Ziyuan Gong and Rui Zhou (University of Electronic Science and Technology of China, China)

0
Security is of vital importance in public places. Detection of suspicious objects such as metal and liquid often requires dedicated and expensive equipment, preventing its wide deployment. This paper proposes a pervasive device-free method to detect suspicious objects concealed by walking pedestrians using WiFi Channel State Information (CSI). By analyzing the different variations of subcarrier amplitude caused by different materials, the proposed method is able to detect suspicious objects such as metal and liquid concealed by pedestrians, when they walk through the transmission link of the WiFi transmitter and receiver. The proposed method employs Convolutional Neural Network (CNN) to classify suspicious objects, on which majority voting is applied to vote for the final result, in order to improve the detection accuracy for walking pedestrians. Evaluations show that the proposed method with majority voting achieve the detection accuracy of 93.3% for metal and liquid concealed by walking pedestrians, 95.6% for exposed metal and liquid carried by walking pedestrians, and 100% for metal and liquid carried by standing pedestrians.

Human Motion Patterns Recognition based on RSS and Support Vector Machines

Sameer Ahmad Bhat and Abolfazl Mehbodniya (Kuwait College of Science and Technology, Kuwait); Ahmed Elsayed Al Wakeel (KCST University, Kuwait); Julian L Webber (Osaka University & Advanced Telecommunications Research Institute International, Japan); Khalid Albegain (Kuwait College of Science and Technology, Kuwait)

0
In this paper, we propose a novel received signal strength (RSS) and machine learning (ML) based system for recognizing human motion walking patterns. Our proposed system eliminates the need to attach sensors on a human body, thereby enabling a non-invasive monitoring system. The proposed system model exploits the potential of a single channel RSS in precisely identifying unique human motion patterns in indoor environments and implements a support vector machine (SVM) algorithm for higher pattern detection accuracy. We validate our proposed model by developing a testbed setup based on state-of-the-art Software Defined Radios (SDRs) and provide a comparative analysis of machine learning models used in the patterns classification process. Our study results reveal that unique walking patterns embedded within RSS and with machine learning classifier, can precisely help in identifying human motion patterns with detection accuracy of approximately 99 percent. The study results impact research scholars actively engaged in developing human motion recognition systems, intrusion detection systems, or healthcare monitoring systems, and in those developing innovative and efficient techniques for monitoring and control systems.

Location-Free CSI Based Activity Recognition With Angle Difference of Arrival

Yanan Li (Beijing University of Posts and Telecommunications, China); Ting Jiang (Beijing University of Posts & Telecommunications, China); Xue Ding and Yangyang Wang (Beijing University of Posts and Telecommunications, China)

0
Device-free activity recognition is an indispensable technology in Human-Computer Interaction (HCI). The activity recognition system based on WiFi signals relying on the wide coverage of WiFi makes HCI more convenient. The previous research on WiFi-based activity recognition system has achieved high recognition accuracy. While the challenge that activity recognition is limited to fixed location and complex background, remains unresolved. In this paper, we propose a location-free activity recognition system which leverages fine-grained channel state information (CSI) to recognize same activities regardless of different locations and background. With CSI recorded in the Network Interface Card (NIC), Angle Difference of Arrival (ADoA) is reckoned to eliminate the location and background information, which is only consistent with the activity tendency. Then the Principal Component Analysis (PCA) method is utilized to reduce the dimension and followed by curve smoothing to make the signal more smoother. Furthermore, Bidirectional Long Short-Term Memory (BiLSTM) network is selected as ideal training machine to deal with issues that are highly correlated with time series. We use two commercial wireless network cards in the typical life scene, and finally achieve 93.7% of recognition accuracy.

Session Chair

Hyun Jong Yang (UNIST, Korea)

Play Session Recording
Session T1-S23

Machine-Type Communications

Conference
2:00 PM — 3:30 PM KST
Local
May 28 Thu, 1:00 AM — 2:30 AM EDT

Enhancing Physical Layer Security Using Underlay Full-Duplex Relay-Aided D2D Communications

Majid H Khoshafa, Telex M. N. Ngatched and Mohamed Hossam Ahmed (Memorial University of Newfoundland, Canada); Ahmed Mohamed Ali Ibrahim (Memorial University, Canada)

1
This paper investigates physical layer security and data transmission in cellular networks with inband underlay Device-to-Device (D2D) communication, where there is no direct links between D2D users. We propose the use of full-duplex (FD) transmission and dual antenna selection at the relay node. Thanks to the FD transmission, the relay node can simultaneously act as a jammer to enhance the cellular network secrecy performance, while improving the D2D communication data transmission. This describes a practical attractive scheme, where spectrum sharing is beneficial for both the D2D and cellular networks in terms of throughput enhancement and security provisioning, respectively. We analyze the secrecy performance of the cellular network and derive closed-form expressions for the secrecy outage probability (SOP) and the probability of non-zero secrecy capacity. We also derive a closed-form expression of the D2D outage probability. Furthermore, asymptotic analysis for SOP is performed. Simulation and numerical results are provided to verify the efficiency of the proposed scheme and to validate the accuracy of the derived expressions.

An Exclusion-Based D2D Activation Scheme in Cellular Networks with Hybrid Spectrum Allocation

Libo Chen and Na Deng (Dalian University of Technology, China); Haichao Wei (Dalian Maritime University, China)

0
Despite of the promising benefits brought by device- to-device (D2D) technique, the attainable performance gains in an underlaying network may still be eroded by the severe mutual interference between cellular and D2D communications. To address this critical issue, we first propose an exclusion- based D2D activation (EDA) scheme with hybrid spectrum allocation to suppress the mutual interference and improve the user performance, where only the D2D users outside the exclusion regions are active and share the frequency band with the cellular users within the exclusion regions. Secondly, we establish a stochastic geometry-based analytical framework and analyze the success probabilities of both cellular and D2D users, where the distribution of the activated D2D pairs follows a bipolar Poisson hole process. The results demonstrate the significant performance improvement and the effectiveness on the interference suppression brought by the proposed EDA scheme and the hybrid spectrum allocation.

A Scalable Mobile Multi-node Channel Sounder

Stefan Zelenbaba (AIT Austrian Institute of Technology, Austria); David Löschenbrand (AIT Austrian Institute of Technology GmbH, Austria); Markus Hofer (AIT Austrian Institute of Technology, Austria); Anja Dakić (AIT - Austrian Institute of Technology, Austria); Benjamin Rainer, Gerhard Humer and Thomas Zemen (AIT Austrian Institute of Technology GmbH, Austria)

1
The advantages of measuring multiple wireless links simultaneously has been gaining attention due to the growing complexity of wireless communication systems. Analyzing vehicular communication systems presents a particular challenge due to their rapid time-varying nature. Therefore multi-node channel sounding is crucial for such endeavors. In this paper, we present the architecture and practical implementation of a scalable mobile multi-node channel sounder, optimized for use in vehicular scenarios. We perform a measurement campaign with three moving nodes, which includes a line of sight (LoS) connection on two links and non LoS (NLoS) conditions on the third link. We present the results on the obtained channel delay and Doppler characteristics, followed by the assessment of the degree of correlation of the analyzed channels and timevariant channel rates, hence investigating the suitability of the channel's physical attributes for relaying. The results show low cross-correlation between the transfer functions of the direct and the relaying link, while a higher rate is calculated for the relaying link.

Training Sequence Based Doppler Shift Estimation for Vehicular Communication

Qingpeng Ma (Beijing University of Posts and Telecommunications, China); Gang Qiu (ZTE Corporation, China); Qixun Zhang, Huiqing Sun and Zhiyong Feng (Beijing University of Posts and Telecommunications, China); Zhu Han (University of Houston, USA)

0
To guarantee the safety requirements of autonomous driving vehicles, the efficient and robust sensing information sharing among vehicles is crucial to overcome the environment sensing limitations beyond a single sensor or vehicle. The millimeter wave (mmWave) technology is considered as one of the potential mobile broadband communication solutions to solve high data rate sensing information sharing problem among vehicles with the low latency constraint. However, the Doppler shift effect is much more severe, which will deteriorate the performance of vehicular communication links, especially in a high speed vehicle communication scenario in the mmWave frequency band. Therefore, we propose a training sequence based estimator (TSBE) by designing a hybrid structure combining the fixed section and the repeated sequences, aiming to achieve a fast and accurate Doppler shift estimation (DSE) in the mmWave vehicular scenario. The fixed section provides a fast estimation, and the accuracy of DSE can be effectively improved by the random correlation selection of repeated sequences. Furthermore, the key performances of our proposed DSE algorithm are evaluated by both the linklevel simulation and the hardware testbed results. Results prove that the mean-squared error of our proposed TSBE algorithm outperforms other conventional algorithms under various signal to noise ratio values. The hardware testbed shows a remarkable performance improvement on the error vector magnitude and the bit error rate using our proposed TSBE and compensation algorithm.

Relay-assisted Device-to-Device Networks: Connectivity and Uberization Opportunities

Quentin Le Gall (Inria & Orange Labs Networks, France); Bartlomiej Błaszczyszyn (Inria-Ens, France); Elie Cali (Orange, France); Taoufik En-Najjary (Orange Labs, France)

0
It has been shown that deploying device-to-device (D2D) networks in urban environments requires equipping a considerable proportion of crossroads with relays. This represents a necessary economic investment for an operator. In this work, we tackle the problem of the economic feasibility of such relay- assisted D2D networks. First, we propose a stochastic model taking into account a positive surface for streets and crossroads, thus allowing for a more realistic estimation of the minimal number of needed relays. Secondly, we introduce a cost model for the deployment of relays, allowing one to study operators' D2D deployment strategies. We investigate the example of an uberizing neo-operator willing to set up a network entirely relying on D2D and show that a return on the initial investment in relays is possible in a realistic period of time, even if the network is funded by a very low revenue per D2D user. Our results bring quantitative arguments to the discussion on possible uberization scenarios of telecommunications networks.

Session Chair

Jemin Lee (Daegu Gyeongbuk Institute of Science and Technology (DGIST), Korea (South))

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Session T1-S24

Polar Code

Conference
2:00 PM — 3:30 PM KST
Local
May 28 Thu, 1:00 AM — 2:30 AM EDT

Index Modulated Polar Codes

YaJing Deng (Harbin Institute of Technology, Shenzhen, China); Shaohua Wu (Harbin Institute of Technology, China); Xijin Liu (Shenzhen Graduate School, Harbin Institute of Technology, China); Dongqing Li (Harbin Institute of Technology (Shenzhen), China); Jian Jiao (Harbin Institute of Technology - Shenzhen, China); Qinyu Zhang (Shenzhen Graduate School, Harbin Institute of Technology, China)

0
Polar codes with short code length under successive cancellation (SC) decoding are inferior to other advanced codes of similar block length. Although more sophisticated algorithms, such as SC list (SCL) decoding and SC stack (SCS) decoding were introduced to address the problem, the complexity of these algorithms has also increased. In this paper, we first propose a novel construction of Polar codes, named index modulated Polar (IM-Polar) codes. This scheme conveys information not only by the information bits in non-frozen channels as conventional Polar codes, but also by the indices of channels, which are activated according to the incoming bit stream. Moreover, we give a specific implementation of IM-Polar codes under cyclic redundancy check (CRC) aided SCL (CA-SCL) decoding. In this implementation, repetition-assisted encoding is employed to improve the accuracy of index detection. It is shown via simulations that the proposed implementation of IM-Polar codes can provide gain of 0.2 — 0.3 dB over the classical CRC-aided Polar (CA-Polar) codes with code rate 0.357 and code length 128 at the bit error ratio (BER) of 10-4.

Simplified Successive-Cancellation List Decoding of Non-Binary Polar Codes with Rate-1 Node

Baoping Feng, Rong Ke Liu and He Sun (Beihang University, China)

0
In this paper, one of the constituent codes, Rate- 1 node, is used to simplify Successive-Cancellation List (SCL) decoding of non-binary polar codes for reducing the decoding complexity. First, we derive the Logarithmic Likelihood Ratio based (LLR-based) path metric of non-binary polar codes in SCL decoding. Then we propose that the path metric only depends on the LLR value at the top of Rate-1 node tree, which avoids traversing a complete decoding tree in non-binary SCL decoding. Finally, we design a novel reliability metric, which is used to select the unreliable symbols from the LLRs at the top of Rate- 1 node tree. By the proposed metric, we select the unreliable symbols to generate the candidate paths, which avoids splitting paths for all symbols of Rate-1 node in the conventional SCL decoding. Simulation results show that the proposed non-binary SCL decoding reduces significantly the computation and time complexity without the performance loss.

Path-Metric-Based False Alarm Reduction in Blind Detection of Polar Codes

Hyosang Ju (Sungkyunkwan University, Korea (South)); Min Jang (Samsung Electronics, Korea (South)); Hyunjae Lee and Sang-Hyo Kim (Sungkyunkwan University, Korea (South))

1
In blind detection, the user equipment attempts to decode a set of candidate groups to find its own control information. False alarm (FA) refers to an event in which decoding is successful even though a signal is not transmitted, and is one of several critical issues occurring in a blind detection problem. For CRC-aided polar code, with the limited number of CRC bits, FA occurs when the CRC check passes even though there is no signal. In this paper, we propose a technique to efficiently reduce FA events using two detection metrics which are specially suited to low rate and high rate codes. Simulation results show that the application of the proposed DMs outperform the conventional schemes. To be specific, at high rates, the proposed scheme reduces 90% of FA compared to the standard CRC-based detection.

Polar Coded Faster-than-Nyquist (FTN) Signaling with Symbol-by-Symbol Detection

Abdulsamet Caglan (Gebze Technical University, Turkey); Adem Cicek (Ankara Yildirim Beyazit Universitesi, Turkey); Enver Cavus (Ankara Yildirim Beyazit University, Turkey); Ebrahim Bedeer (University of Saskatchewan, Canada); Halim Yanikomeroglu (Carleton University, Canada)

2
Reduced complexity faster-than-Nyquist (FTN) signaling systems are gaining increased attention as they provide improved bandwidth utilization for an acceptable level of detection complexity. In order to have a better understanding of the tradeoff between performance and complexity of the reduced complexity FTN detection techniques, it is necessary to study these techniques in the presence of channel coding. In this paper, we investigate the performance a polar coded FTN system which uses a reduced complexity FTN detection, namely, the recently proposed "successive symbol-by-symbol with go-back- K sequence estimation (SSSgbKSE)" technique. Simulations are performed for various intersymbol-interference (ISI) levels and for various go-back-K values. Bit error rate (BER) performance of Bahl-Cocke-Jelinek-Raviv (BCJR) detection and SSSgbKSE detection techniques are studied for both uncoded and polar coded systems. Simulation results reveal that polar codes can compensate some of the performance loss incurred in the reduced complexity SSSgbKSE technique and assist in closing the performance gap between BCJR and SSSgbKSE detection algorithms.

On List Decoding of 5G-NR Polar Codes

Charles Pillet (Huawei Technologies Co. Ltd., France); Valerio Bioglio (France Research Center, Huawei Technologies Co. Ltd., Italy); Carlo Condo (Huawei Technologies Co. Ltd., France)

2
The 5th generation wireless systems (5G) standardization process of the 3rd generation partnership project (3GPP) chose polar codes as a channel coding scheme for the control channel. In case of downlink control information, polar codes are concatenated with distributed distributed cyclic redundancy check (CRC). Whereas CRC bits allow to improve the performance of successive cancellation list (SCL) decoders by improving distance properties, distributed CRC bits allow for path pruning and decoding early-termination. In this paper, we show how to take advantage of the distributed CRC to improve SCL decoding, analyzing various schemes having different early- termination and error correction properties. Simulation results compare the proposed decoding schemes, showing different tradeoffs between error-correction performance and early-termination with different decoder parameters.

Session Chair

SongNam Hong (Ajou University, Korea (South))

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Session T1-S25

Performance Analysis 2

Conference
2:00 PM — 3:30 PM KST
Local
May 28 Thu, 1:00 AM — 2:30 AM EDT

Improperness Based SINR Analysis of GFDM Systems Under Joint Tx and Rx I/Q Imbalance

Hao Cheng (School of Information Science and Engineering, Southeast University, China); Xia Yili, Yongming Huang and Luxi Yang (Southeast University, China); Zixiang Xiong (Texas A&M University & Monash University, USA); Danilo Mandic (Imperial College, London, United Kingdom (Great Britain))

1
Adverse impacts of in-phase and quadrature-phase (I/Q) imbalance in both the transmitter (Tx) and receiver (Rx) are quantified for the generalized frequency division multiplexing (GFDM) based transmission over frequency selective fading channels. To this end, we first equip the standard signal-to- interference-plus-noise (SINR) performance evaluation with the ability to consider second-order noncircular (improper) signals, and thus precisely evaluate performance deterioration caused by I/Q distortions over the in-phase (I) and quadrature-phase (Q) channels of a transmission system. Next, we propose a novel means to evaluate the individual SINR contributions from both the channels of GFDM, and hence, provide more meaningful insights into the underlying wireless transmission in the presence of complex noncircularity. This is accompanied by an account of complete augmented second-order statistics of I/Q imbalanced GFDM waveforms which caters for various sources of complex improperness. Simulations in the GFDM system setting support our analysis.

Optimal Antenna Selection and Power Adaptation for Underlay Spectrum Sharing with Statistical CSI

Rimalapudi Sarvendranath (IISc, India); Neelesh B. Mehta (Indian Institute of Science, India)

0
For underlay spectrum sharing, transmit antenna selection is a low hardware complexity technique that can help the secondary system overcome the performance limitations imposed by the constraints on the interference it causes to a primary system. However, its efficacy depends on the channel state information (CSI) available to the secondary transmitter. We consider a practically appealing model in which the secondary transmitter has only statistical CSI about the channel gains from itself to the primary receiver and is subject to a general class of stochastic interference constraints. We derive an optimal and novel joint antenna selection and continuous power adaptation rule for it that minimizes the average symbol error probability (SEP) of the secondary system. We show that it has an intuitively appealing separable structure. We then analyze its average SEP. Our numerical results evaluate the impact of the interference constraint on both secondary and primary systems, and show that a judicious choice of the interference constraint and its parameters is needed as its impact on the secondary and primary systems can be very different.

Random Caching Strategy in HetNets with Random Discontinuous Transmission

Li Hu (Harbin Institute of Technology (Shenzhen), China); Fu-Chun Zheng (Harbin Institute of Technology, Shenzhen, China & University of York, United Kingdom (Great Britain)); Jingjing Luo (Harbin Institute of Technology, Shenzhen); Xu Zhu (University of Liverpool, United Kingdom (Great Britain) & Harbin Institute of Technology, Shenzhen, China)

0
In this paper, we jointly explore random caching and cooperative transmission in heterogenous networks (HetNets) with random discontinuous transmission (DTX). We consider a realistic scenario where joint transmission is not always available and assume two cases depending on whether joint transmission is available. With the help of stochastic geometry, a tractable expression for the average successful transmission probability (STP) is obtained. We then formulate the STP optimization problem to find the optimal caching policy. In addition, we analyze the STP under random DTX. Compared with several existing caching policies in the previous works, we show that the optimal caching policy indeed achieves a significant performance gain.

Multichannel ALOHA with Exploration Phase

Jinho Choi (Deakin University, Australia)

0
In this paper, we consider exploration for multi-channel ALOHA by transmitting preambles before transmitting data packets and show that the maximum throughput can be improved by a factor of 2 — e-1 ≈ 1.632, which can be seen as the gain of exploration. In the proposed approach, a base station (BS) needs to send the feedback information to active users to inform the numbers of transmitted preambles in multiple channels, which can be reliably estimated as in compressive random access. Simulation results also confirm the results from analysis.

An Analysis of Coded Caching Under Arbitrary Popularity Distributions

Abdollah Ghaffari Sheshjavani, Ahmad Khonsari and Seyed Pooya Shariatpanahi (University of Tehran, Iran); Masoumeh Moradian (IPM, Iran); Aresh Dadlani (Nazarbayev University, Kazakhstan)

0
Content caching is a technique aimed to reduce the network load imposed by data transmission during peak time while ensuring users' quality of experience. Studies have shown that content delivery via coded caching can significantly improve beyond the performance limits of conventional caching schemes when caches and the server share a common link. Finding the optimal cache content placement however, becomes challenging under arbitrary distributions of content popularity. While existing works show that partitioning contents into three popularity levels performs better when multiple requests are received at each time slot, they neither delve into the problem analysis nor derive closed-form expressions for the optimum partitioning problem. In this paper, we analyze the coded caching scheme for a system with arbitrary content popularity, where we derive explicit closed-forms for the server load in the delivery phase and formulate the near-optimum partitioning problem. Simulation results are presented to corroborate our mathematical analysis.

Session Chair

Taesoo Kwon (Seoul National University of Science and Technology, Korea (South))

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Session T1-S26

Hardware and Implementation

Conference
2:00 PM — 3:30 PM KST
Local
May 28 Thu, 1:00 AM — 2:30 AM EDT

Symbiotic Radio: A New Application of Large Intelligent Surface/Antennas (LISA)

Qianqian Zhang and Ying-Chang Liang (University of Electronic Science and Technology of China, China); H. Vincent Poor (Princeton University, USA)

1
To overcome the challenges in achieving extremely high throughput and super-massive access in future wireless communications, in this paper, we focus on a novel large intelligent surface/antennas (LISA)-assisted symbiotic radio (SR) system. Specifically, in the proposed system, a LISA transmits messages to its destination by using backscatter communication, and at the same time, it assists the transmission from a base station (BS) to its user by intelligently reconfiguring the wireless environment. In this paper, we are interested in the joint active (BS) and passive (LISA) beamforming design problem to maximize the transmission rate of LISA subject to the BS transmission rate constraint. Due to the non-convexity of the problem, we first relax the rank-one constraint based on the technique of semi-definite relaxation (SDR) and then decouple that optimization problem into two subproblems based on the block coordinate descent (BCD) method, each of which is a convex problem. Due to the expectation terms in the constraints, we propose two algorithms called the Lagrangian algorithm and approximate algorithm to address it. Finally, simulation results are presented to validate the effectiveness of the proposed algorithms and the superiority of the proposed system.

Short-Range Ambient Backscatter Communication Using Reconfigurable Intelligent Surfaces

Mahyar Nemati, Jie Ding and Jinho Choi (Deakin University, Australia)

1
Ambient backscatter communication (AmBC) has been introduced to address communication and power efficiency issues for short-range and low-power Internet-of-Things (IoT) applications. On the other hand, reconfigurable intelligent surface (RIS) has been recently proposed as a promising approach that can control the propagation environment especially in indoor communication environments. In this paper, we propose a new AmBC model over ambient orthogonal-frequency-division-multiplexing (OFDM) subcarriers in the frequency domain in conjunction with RIS for short-range communication scenarios. A tag transmits one bit per each OFDM subcarrier broadcasted from a WiFi access point. Then, RIS augments the signal quality at a reader by compensating the phase distortion effect of multipath channel on the incident signal. We also exploit the special spectrum structure of OFDM to transmit more data over its squeezed orthogonal subcarriers in the frequency domain. Consequently, the proposed method improves the bit-error-rate (BER) performance and provides a higher data rate compared to existing AmBC methods. Analytical and numerical evaluations show the superior performance of the proposed approach in terms of BER and data rate.

Two-Way Communications via Reconfigurable Intelligent Surface

Saman Atapattu (University of Melbourne, Australia); Rongfei Fan (Beijing Institute of Technology, China); Prathapasinghe Dharmawansa (University of Moratuwa, Sri Lanka); Gongpu Wang (Beijing Jiaotong University, China); Jamie S Evans (University of Melbourne, Australia)

2
The novel reconfigurable intelligent surface (RIS) is an emerging technology which facilitates high spectrum and energy efficiencies in Beyond 5G and 6G wireless communication applications. Against this backdrop, this paper investigates two-way communications via reconfigurable intelligent surfaces (RISs) where two users communicate through a common RIS. We assume that uplink and downlink communication channels between two users and the RIS can be reciprocal. We first obtain the optimal phase adjustment at the RIS. We then derive the exact outage probability and the average throughput in closed- forms for single-element RIS. To evaluate multiple-element RIS, we first introduce a gamma approximation to model a product of Rayleigh random variables, and then derive approximations for the outage probability and the average throughput. For large average signal-to-interference-plus-noise ratio (SINR) ρ, asymptotic analysis also shows that the outage decreases at the rate (log(ρ)/ ρ)L where L is the number of elements, whereas the throughput increases with the rate log(ρ).

Programmable Metasurface Transmitter Aided Multicast Systems

Xiaoling Hu and Caijun Zhong (Zhejiang University, China); Yongxu Zhu (London South Bank University, United Kingdom (Great Britain)); Xiaoming Chen and Zhaoyang Zhang (Zhejiang University, China)

0
This paper considers a multi-antenna multicast system with programmable metasurface (PMS) based transmitter. Taking into account of the finite-resolution phase shifts of PMSs, a novel beam training approach is proposed, which achieves comparable performance as the exhaustive beam searching method but with much lower time overhead. Then, a closed-form expression for the achievable individual rate is presented, which is valid for arbitrary system configurations. Besides, assuming a large number of reflecting elements, a simple approximated expression for the multicast rate is derived. A closed-form solution is obtained for the optimal power allocation scheme, and it is shown that equal power allocation is optimal when the number of reflecting elements is sufficiently large. The analytical findings indicate that, increasing the number of radio frequency (RF) chains or reflecting elements can significantly improve the multicast rate, and as the phase shift number becomes larger, the multicast rate improves first and gradually converges to a limit. Moreover, increasing the number of users would significantly degrade the multicast rate, but this rate loss can be compensated by implementing a large number of reflecting elements.

Advanced Hardware Architectures for Turbo Code Decoding Beyond 100 Gb/s

Stefan Weithoffer (IMT Atlantique, France); Oliver Griebel (University of Kaiserslautern, Germany); Rami Klaimi and Charbel Abdel Nour (IMT Atlantique, France); Norbert Wehn (University of Kaiserslautern, Germany)

4
In this paper, we present two new hardware architectures for Turbo Code decoding that combine functional, spatial and iteration parallelism. Our first architecture is the first fully pipelined iteration unrolled architecture that supports multiple frame sizes. This frame flexibility is achieved by providing a set of interleavers designed to achieve a hardware implementation with a reduced routing overhead. The second architecture efficiently utilizes the dynamics of the error rate distribution for different decoding iterations and is comprised of two stages. First, a fully pipelined iteration unrolled decoder stage applied for a pre-determined number of iterations and a second stage with an iterative afterburner-decoder activated only for frames not successfully decoded by the first stage. We give post place & route results for implementations of both architectures for a maximum frame size of K =3D 128 and demonstrate a throughput of 102 4 Gb/s in 28 nm FDSOI technology. With an area efficiency of 6.19 and 7.15 Gb/s/mm2 our implementations clearly outperform state of the art.

Session Chair

Jian Wang (Seoul National University, Korea (South))

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Session T3-S23

Mobility and Handoff Management

Conference
2:00 PM — 3:30 PM KST
Local
May 28 Thu, 1:00 AM — 2:30 AM EDT

Efficient Drone Mobility Support Using Reinforcement Learning

Yun Chen (The University of Texas at Austin, USA); Xingqin Lin (Ericsson Research, USA); Talha Ahmed Khan (Ericsson Research); Mohammad Mozaffari (Ericsson Research, Santa Clara, CA, USA., USA)

0
Flying drones can be used in a wide range of applications and services from surveillance to package delivery. To ensure robust control and safety of drone operations, cellular networks need to provide reliable wireless connectivity to drone user equipments (UEs). To date, existing mobile networks have been primarily designed and optimized for serving ground UEs, thus making the mobility support in the sky challenging. In this paper, a novel handover (HO) mechanism is developed for a cellular-connected drone system to ensure robust wireless connectivity and mobility support for drone-UEs. By leveraging tools from reinforcement learning, HO decisions are dynamically optimized using a Q-learning algorithm to provide an efficient mobility support in the sky. The results show that the proposed approach can significantly reduce (e.g., by 80%) the number of HOs, while maintaining connectivity, compared to the baseline HO scheme in which the drone always connects to the strongest cell.

ProSCH: Proxy aided Secondary Cell Handover in Ultra-Dense mmWave Network

Goodsol Lee, Siyoung Choi, Junseok Kim, Kim Youngseok and Saewoong Bahk (Seoul National University, Korea (South))

1
The ultra-dense network (UDN) is a promising technology that overcomes the instability of high-frequency millimeter wave (mmWave) communication in a cellular network. With a short distance between cells and variability of mmWave, a handover occurs frequently in UDN with mmWave. Hence fast handover is essential to provide reliable service. One of the important things for fast handover is prompt signaling between base stations (BSs) through backhaul. However, conventional handovers assumed backhaul has very short latency with ideal deployment. In practice, with non-ideal latency and deployment of backhaul, handover is delayed for backhaul. We find that this delayed handover led to the performance reduction of TCP, the dominant traffic of nowadays. So we propose a ProSCH, the novel handover scheme that operates on a practical backhaul network while guaranteeing TCP performance. ProSCH reduces a handover interruption time by considering the backhaul latency in the handover signaling process, and uses a TCP proxy on BS to forward data without loss after handover. Through extensive ns-3 simulation, we show that ProSCH outperforms conventional schemes in terms of handover interruption time, backhaul load, throughput, and delay.

Robust TOA-Based Source Self-Positioning With Clock Imperfection

Pengcheng He, Xiaohu Jiang and Qingjiang Shi (Tongji University, China)

0
Source positioning is a key issue in a range of applications such as sensing, monitoring and tracking, etc. In this paper, we address the source localization problem with unknown clock skew and outliers in the TOA measurements. Considering the measurement outliers, we present a robust localization formulation by introducing Huber loss. Furthermore, we develop a lightweight iterative localization algorithm using majorization-minimization (MM) method with guaranteed convergence. In addition, we propose a novel semidefinite-relaxation- based algorithm for the proposed robust localization formulation. Simulations demonstrate that our proposed MM-based localization algorithms could achieve better performance than SDR-based localization algorithms in terms of both localization accuracy and computational time, for both cases with or without outliers.

On the Feasibility of Location-based Discovery and Vertical Handover in IEEE 802.11ah

Serena Santi (University of Antwerp - imec, Belgium); Filip Lemic (University of Antwerpen - imec, Belgium); Jeroen Famaey (University of Antwerp & Imec, Belgium)

1
Multi-Radio Access Technology (RAT) IoT devices are able to combine the high coverage of Low-Power Wide-Area (LPWA) technologies with the higher data-rates of shorter range technologies such as IEEE 802.11ah. In such scenarios, a discovery procedure has to be used for detecting the availability of a IEEE 802.11ah network. Currently, these procedures consume substantial energy, as the discovery has to be periodically performed, even if the IEEE 802.11ah technology is not available, which is undesirable for low-power Internet of Things (IoT) devices. We propose using the device's location information for making more optimized discovery and handover decisions. We demonstrate the feasibility of this approach in performing energy efficient handovers between various LPWA technologies and IEEE 802.11ah based on estimated location. We carry out our evaluation in terms of the energy consumption of the procedure and the duration of the device's association to IEEE 802.11ah. We show that the location-based procedure substantially reduces the energy consumption of the mobile device compared to the traditional discovery based on periodical listening for beacons.

Cellular Network Planning under Variable QoS Requirements Using Voronoi Algorithm

Mohsen Abedi (Aalto University, Finland); Risto Wichman (Aalto University School of Electrical Engineering, Finland)

1
We study the optimization of base station (BS) localization in cellular networks with non-uniform service demand distribution taking into account a variety of server-side and user-side requirements. To this end, we propose a power Voronoi algorithm (PVA) to obtain uniform traffic volume shares per cell while simultaneously meeting the user-side and server-side requirements of the heterogeneous devices. We describe a numerical method to solve the optimization problem by updating the weights associated to different cells in the PVA. Then, we take into account minimum signal to interference plus noise ratio at all devices as a user-side requirement. It is observed that BSs are concentrated in the areas with condensed demand and high SINR requirements. To show the advantages of the proposed method, the results are compared for different SINR requirement distributions giving insight on the performance of the algorithm.

Session Chair

Mohsen Abedi (Aalto University, Finland)

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Session T3-S24

Rate Control and Transport Protocol

Conference
2:00 PM — 3:30 PM KST
Local
May 28 Thu, 1:00 AM — 2:30 AM EDT

Bandwidth profile for multi-timescale fairness

Szilveszter Nádas (Ericsson Research, Hungary); Balazs Varga (Ericsson, Hungary); Illes Horvath (MTA-BME Information Systems Research Group); Andras Meszaros (Technical University of Budapest (BME), Hungary); Miklos Telek (Technical University of Budapest, Hungary)

0
We propose a novel approach to provide fairness on multiple timescales in the framework of core-stateless resource sharing paradigm. We illustrate the unique advantages of multi- timescale fairness. We introduce a new marking scheme, called multi-timescale bandwidth profile. It assigns drop precedence to flows based on their traffic history on multiple timescales. Additionally, we provide dimensioning guidelines for the introduced profile in an access-aggregation network scenario and present its simulation-based performance analysis.

Source Rate Control for Opportunistic Routing

Che-Jung Hsu (Fu Jen Catholic University, Taiwan); Huey-Ing Liu (Fu-Jen Catholic University, Taiwan)

0
Due to the popularity of wireless networks, opportunistic routing emerges and improves performance by utilizing the broadcast nature of wireless communication. However, without controlling source rate, capacity of bottleneck could be consumed by its neighbors and that leads to lower throughput. This work showed how source rate impacts the performance of opportunistic routing and proposed a source rate-based congestion control at layer 2 for better throughput. Simulation results showed that throughput is improved by about 35% with source rate control and fewer resources consumed.

SMS: Smart Multipath Switch for improving the throughput of Multipath TCP for Smartphones

Madhan Raj Kanagarathinam (Samsung R&D Institute India Bangalore, India); Harikrishnan Natarajan (Reliance Jio Infocomm Pvt Ltd, India); Karthikeyan Arunachalam (Samsung R&D Institute India - Bangalore, India); Sandeep Irlanki (Samsung R&D Institute & Samsung, India); Venkata Sunil Kumar (Samsung R&D India - Bangalore, India)

2
Multipath TCP (MPTCP) is an enhancement of TCP, capable of using multiple network paths to enhance the throughput and reliability. The current implementation of MPTCP does not consider wireless network characteristics. Unlike the wired networks, the path characteristic and mode of operations may vary among various wireless network interfaces dynamically. Hence we propose Smart Multipath Switch (SMS), dynamic MPTCP subflow management for the wireless network. SMS uses a learning-based approach, adapts to ad-hoc wireless conditions, thereby dynamically controls and manages the subflow in MPTCP for better user experience and network utilization. To demonstrate the effectiveness of our proposal, we performed live air experiments with the help of Samsung Galaxy S8 in different locations (Korea, Thailand, and India) and also performed simulations in our lab at Samsung Electronics, Headquarters. Our experiments show that the proposed solution provides the aggregation ratio consistently above 80%. Furthermore, the SMS, using auto-tuning logic, improves the throughput by up to 51.5% compared with legacy.

CQUIC: Cross-Layer QUIC for Next Generation Mobile Networks

Gaurav Sinha and Madhan Raj Kanagarathinam (Samsung R&D Institute India Bangalore, India); Sujith Rengan Jayaseelan (Samsung R&D Institute India - Bangalore, India); Gunjan Kumar Choudhary (Samsung Research & Development India, Bangalore, India)

2
Requirements for Next Generation Mobile Networks (NGMN) include low latency, higher throughput, scalability, and energy efficiency. As 5G millimeter wave (mmWave) band is short-range, the handover is inevitable. Google proposed QUIC (Quick UDP Internet Connection), which aims to address these challenges. However, Google QUIC (GQUIC), follows "WiFi-First" policy causing frequent network switching, which can lead to a throughput reduction and fast battery degradation. In this paper, we propose Cross-layer QUIC (CQUIC) framework, that follows "WiFi-if-best" policy to enhance the throughput and resilience by using a Cross-Layer approach. CQUIC proposes a novel migration scheme in QUIC which adapts to the dynamic network characteristics. GQUIC protocol with low bandwidth and high round-trip-time fail to migrate for seamless User Experience. CQUIC algorithm predicts Cross- Layer Score (CLS) which incorporates predicted Signal-to- Interference Noise Ratio (SINR), QUIC Bandwidth, round-trip- time (RTT) stats from QUIC Session and models the handover decision pro-actively. Compared with state-of-the-art methods such as GQUIC and HTTP (using TCP) this paper reveals the significant benefits of the proposed method. A series of experimental results obtained in live air network over Samsung Galaxy S10 devices show CQUIC outperforms the GQUIC by 20%, TCP by 36% and MPTCP (Backup) by 17% in terms of throughput. Furthermore, CQUIC compared with MPTCP, reduces the data consumption over mobile network and operates green by reducing the power consumption by 25%.

Novel MultiPipe QUIC Protocols to Enhance the Wireless Network Performance

Gunjan Kumar Choudhary (Samsung Research & Development India, Bangalore, India); Madhan Raj Kanagarathinam (Samsung R&D Institute India Bangalore, India); Karthikeyan Arunachalam and Sujith Rengan Jayaseelan (Samsung R&D Institute India - Bangalore, India); Harikrishnan Natarajan (Reliance Jio Infocomm Pvt Ltd, India); Debabrata Das (International Institute of Information Technology - Bangalore, India); Gaurav Sinha (Samsung R&D Institute India Bangalore, India)

3
To improve the performance of the Transmission Control Protocol (TCP), the Quick UDP Internet Connections (QUIC) was introduced. However, from the recent literature, in the wireless networks, QUIC does not fully utilize the link capacity, because of varying network wireless medium characteristics for an application. To the best of our knowledge, for the first time, this paper has proposed two novel protocols to overcome the wireless network's challenges, by MultiPipe (multi sessions) QUIC protocol (MP-QUIC). The two MP-QUIC's novel protocols are (i) Round Robin MP-QUIC (RR-MP-QUIC) and (ii) Cross-Layer Burst Aware MP-QUIC (CBA-MP-QUIC). In RR-MP-QUIC, multiple pipes are created between source as well as destination and assign a pipe to each object in a round-robin manner. We set up the testbed over live air commercial network. The experimental results reveal that the RR-MP-QUIC Page Load Time (PLT) of a web page decreases by 76% with respect to QUIC. Furthermore, to improve the performance of RR-MP- QUIC, we proposed CBA-MP-QUIC, which optimally creates pipes, efficiently schedules the objects and understands with respect to cross-layer (wireless channel characteristics and load in data link layer) parameters. Hence this adapts dynamically to the network conditions and maintains fairness between the applications in User Equipment (UE) and within the same application. Experimental result of CBA-MP-QUIC on live air improves the web page PLT by 143% with respect to QUIC.

Session Chair

Huey-Ing Liu (Fu Jen Catholic University, Taiwan)

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Session T3-S25

Resource Management and Optimization 2

Conference
2:00 PM — 3:30 PM KST
Local
May 28 Thu, 1:00 AM — 2:30 AM EDT

Centralized Scheduling with Sum-Rate Optimization in Flexible Half-Duplex Networks

Shalanika Gangani Dayarathna (University of Melbourne, Australia); Mohsen Mohammadkhani Razlighi (Monash University, Australia); Rajitha Senanayake (University of Melbourne, Australia); Nikola Zlatanov (Monash University, Australia); Jamie S Evans (University of Melbourne, Australia)

0
In this paper, we focus on maximization of the instantaneous sum-rate in flexible half-duplex networks, where nodes have the flexibility to choose to either transmit, receive or be silent in a given time slot. Since the corresponding optimization problem is NP-hard, we design low-cost algorithms that give sub-optimal solutions with good performance. We first consider two existing approximation techniques to simplify the sum-rate optimization problem: arithmetic-geometric means inequality and another utilising the tight lower bound approximation. We then propose a novel pattern search algorithm that performs close to exhaustive search but with significantly lower complexity. Comparing the performance of the proposed algorithm with respect to existing resource allocation techniques, we observe that our proposed algorithm provides significant sum-rate gains.

Binary Power Optimality for Two Link Full-Duplex Network

Shalanika Gangani Dayarathna, Rajitha Senanayake and Jamie S Evans (University of Melbourne, Australia)

0
In this paper, we analyse the optimality of binary power allocation in a network that includes full-duplex communication links. Considering a network with four communicating nodes, two of them operating in half-duplex mode and the other two in full-duplex mode, we prove that binary power allocation is optimum for the full-duplex nodes when maximizing the sum rate. We also prove that, for half-duplex nodes binary power allocation is not optimum in general. However, for the two special cases, 1) the low signal-to-noise-plus-interference (SINR) regime and, 2) the approximation by the arithmetic mean-geometric mean inequality, binary power allocation is optimum for the approximated sum rate even for the half-duplex nodes. We further analyse a third special case using a symmetric network for which the optimum power allocation is binary, under a sufficient condition. Numerical examples are included to illustrate the accuracy of the results.

Resource Allocation for mMTC/H2H Coexistence with H2H's Success Probability of Data Transmission

Tao Wang, Yichen Wang and Dongyang Xu (Xi'an Jiaotong University, China); Zhangnan Wang (Xi`an Jiaotong University, China)

0
To accommodate massive machine-type communication (mMTC) in the networks originally designed for human- to-human (H2H) communication, we investigate the resource allocation for the mMTC/H2H coexisting network where the conventional random access (RA) and data transmission procedures are tailored for mMTC. The resource allocation strategy jointly consider the resource allocation of physical random access channel (PRACH) and physical uplink shared channel (PUSCH), aiming to support more MTC users while protecting the quality- of-service (QoS) of traditional H2H communication. A Markov chain is utilized to explicitly model the RA and data transmissions of H2H, and H2H's success probability of data transmission is derived under the analysis of stationary distribution. Then, we formulate a nonlinear integer programming (NLIP) problem which aims to maximize MTC throughput while guaranteeing H2H's success probability of data transmission. By solving the optimization problem with a modified particle swarm optimization method, we obtain the resource allocation strategy that achieves a balance between PRACH and PUSCH in terms of resource efficiency. Simulation results demonstrate the superiority of our proposed resource allocation strategy over traditional LTE strategy in the scenario of mMTC/H2H coexistence.

Towards Reconfigurable Intelligent Surfaces Powered Green Wireless Networks

Siyuan Sun (ShanghaiTech University, China); Min Fu (ShanghaiTech University & Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, China); Yuanming Shi and Yong Zhou (ShanghaiTech University, China)

1
The adoption of reconfigurable intelligent surface (RIS) in wireless networks can enhance the spectrum- and energy-efficiency by controlling the propagation environment. Although the RIS does not consume any transmit power, the circuit power of the RIS cannot be ignored, especially when the number of reflecting elements is large. In this paper, we propose the joint design of beamforming vectors at the base station, active RIS set, and phase-shift matrices at the active RISs to minimize the network power consumption, including the RIS circuit power consumption, while taking into account each user's target data rate requirement and each reflecting element's constant modulus constraint. However, the formulated problem is a mixed-integer quadratic programming (MIQP) problem, which is NP-hard. To this end, we present an alternating optimization method, which alternately solves second order cone programming (SOCP) and MIQP problems to update the optimization variables. Specifically, the MIQP problem is further transformed into a semidefinite programming problem by applying binary relaxation and semidefinite relaxation. Finally, an efficient algorithm is developed to solve the problem. Simulation results show that the proposed algorithm significantly reduces the network power consumption and reveal the importance of taking into account the RIS circuit power consumption.

Interference Detection and Resource Allocation in LTE Unlicensed Systems

Lifeng Lai and Daquan Feng (Shenzhen University, China); Fu-Chun Zheng (Harbin Institute of Technology, Shenzhen, China & University of York, United Kingdom (Great Britain))

0
In this paper, we consider the interference detection and resource allocation issue in Long-Term Evolution Unlicensed (LTE-U) system with carrier aggregation (CA). First, to avoid the co-channel interference between the WiFi and LTE-U users, we adopt the logistic regression method to train a classifier model for the base stations (BSs) to find the users that are susceptible to the interference from the WiFi. Then, we formulate the optimization problem with the goal to maximize the downlink (DL) throughput while guaranteeing the quality-of-service (QoS) for each user. To make the original problem more tractable, we first split it into two sequential subproblems and then propose a dual decomposition method to solve them efficiently. The numerical results show that the proposed schemes can significantly improve the overall throughput and outperform the existing schemes.

Session Chair

Rajitha Senanayake (University of Melbourne, Australia)

Play Session Recording
Session T4-S11

Low Power and IoT

Conference
2:00 PM — 3:30 PM KST
Local
May 28 Thu, 1:00 AM — 2:30 AM EDT

NB-IoT Micro-Operator for Smart Campus: Performance and Lessons Learned in 5GTN

Rumana Yasmin (University of Oulu, Finland); Konstantin Mikhaylov (University of Oulu & Solmu Technologies OY, Finland); Muhammad Arif (University of Oulu, Finland); Ari T. Pouttu (Centre for Wireless Communications University of Oulu, Finland); Ville Niemelä (Centre for Wireless Communications, Finland); Olli Liinamaa (Centre for Wireless Communications University of Oulu, Finland)

1
In recent years, many new radio-based connectivity solutions for the Internet of Things (IoT) have been proposed. At the same time, development towards the 6G has brought on the stage the new business concepts. One of them is the concept of the micro-operator and implies the local entities to act as the telecom infrastructure owner and provider in their premises. In the current paper, we discuss the deployment and report the practical performance of a single-cell NB-IoT deployed as a part of the 5G Test Network (5GTN) and controlled by a smart-campus micro-operator. The practical measurements reported in the paper have been carried in the University of Oulu within a huge interconnected indoor environment with the total floor area of 188 600 m2. Our results demonstrate that the NB-IoT technology is a viable connectivity solution for various non-critical machine-based applications deployed indoors, highlight the practical performance of this technology, and reveal some practical specifics and challenges for acting as an IoT micro-operator.

Collaborative Learning Model for Cyberattack Detection Systems in IoT Industry 4.0

Tran Viet Khoa (VNU University of Engineering and Technology, Vietnam); Yuris Mulya Saputra (University of Technology Sydney, Australia & Universitas Gadjah Mada, Indonesia); Hoang Thai Dinh (University of Technology Sydney (UTS), Australia); Nguyen Linh Trung (Vietnam National University, Hanoi, Vietnam); Diep N. Nguyen (University of Technology Sydney, Australia); Nguyen Viet Ha (VNU Ha Noi, Vietnam); Eryk Dutkiewicz (University of Technology Sydney, Australia)

2
Although the development of IoT Industry 4.0 has brought breakthrough achievements in many sectors, e.g., manufacturing, healthcare, and agriculture, it also raises many security issues to human beings due to a huge of emerging cybersecurity threats recently. In this paper, we propose a novel collaborative learning-based intrusion detection system which can be efficiently implemented in IoT Industry 4.0. In the system under consideration, we develop smart "filters" which can be deployed at the IoT gateways to promptly detect and prevent cyberattacks. In particular, each filter uses the collected data in its network to train its cyberattack detection model based on the deep learning algorithm. After that, the trained model will be shared with other IoT gateways to improve the accuracy in detecting intrusions in the whole system. In this way, not only the detection accuracy is improved, but our proposed system also can significantly reduce the information disclosure as well as network traffic in exchanging data among the IoT gateways. Through thorough simulations on real datasets, we show that the performance obtained by our proposed method can outperform those of the conventional machine learning methods.

An Efficient Downlink Receiver Design for NB-IoT

Shutao Zhang, Shiying Zeng and Fenglin Ye (Sun Yat-sen University, China); Ruibo Tang (China Electronics Technology Group Corporation No. 7 Research Institute, China); Peiran Wu and Minghua Xia (Sun Yat-sen University, China)

2
As of the specification Release 13 completed by the 3rd Generation Partnership Project (3GPP) in June 2016, narrowband Internet-of-Things (NB-IoT) has attracted great attention in both academia and industry. Some new features were further specified in subsequent Releases 14 and 15. In light of these specifications, efficient downlink receiver design is critical to the implementation of NB-IoT, due to the strictly limited hardware resources at a receiver. Conforming to Release 15, this paper develops an efficient downlink receiver by jointly accounting for the synchronization, channel estimation and soft combination for repetitive transmissions. Simulation results demonstrate that both the detection probability for the narrowband primary synchronization signal (NPSS) and the block error rate (BLER) for the narrowband physical downlink sharing channel satisfy the benchmarks designated by 3GPP.

An Experimental Performance Evaluation of Bluetooth Mesh Technology for monitoring Applications

Eduardo De Leon and Majid Nabi (Eindhoven University of Technology, The Netherlands)

0
The introduction of Bluetooth Low Energy (BLE) in 2010 provided constrained devices with a wireless point-to- point communication standard. It facilitates the creation of pico-nets and reducing product development time and cost. It is until 2017 that the Bluetooth special interest group releases the Mesh Profile allowing a multi-hop interconnection through BLE's advertisements. Being a relatively new technology, this paper aims to experimentally evaluate its performance and investigate the limits of the technology in terms of data delivery capacity in monitoring applications. Several experiments are performed by deploying a number of BLE nodes in an office environment, making a multi-hop network. The performance of the network in terms of packet delivery to a base station is measured in each experiment. Moreover, experiments including mobile nodes are carried out under the multi-hop setup to test the behaviour of the protocol when some nodes move around. The experimental results show that the relay nodes impose critical limitations for message delivery in multi-hop networks, limiting the usage of the BLM technology for many monitoring applications.

Extending BLE Beacon Lifetime by a Novel Neural Network-driven Framework

Kang Eun Jeon, James She and Tat Yuen Simon Wong (Hong Kong University of Science and Technology, Hong Kong)

0
Bluetooth Low Energy (BLE) beacon networks are a popular infrastructure for IoT and smart city applications due to their scalability and affordability, as well as the proliferation of Bluetooth-enabled devices. However, BLE beacon networks suffer from short battery lifetime, inducing additional maintenance costs. Previous works have tackled this problem by proposing a more energy-efficient BLE beacon firmware that will change its operating configuration based on user existence information. However, previous efforts could not adapt to varying user traffic conditions and therefore was impractical. To address this issue, this paper proposes a novel neural network-driven framework, User-P, that extends beacon lifetime by changing its operating configuration by predicting user traffic conditions. Furthermore, the paper also presents a novel machine learning method tailored for user traffic prediction. Last but not least, the effectiveness of the proposed framework and methods are proven through a set of simulations. The simulation results show that the proposed framework can extend the beacon lifetime by 180% in comparison to that of the state-of-the-art techniques.

Session Chair

Joohyun Lee (Hanyang University, Korea)

Play Session Recording
Session T4-S12

Communications with UAVs

Conference
2:00 PM — 3:30 PM KST
Local
May 28 Thu, 1:00 AM — 2:30 AM EDT

Power Limited Ultra-Reliable and Low-Latency Communication in UAV-Enabled IoT Networks

Kanghua Chen, Ying Wang, Zixuan Fei and Xue Wang (Beijing University of Posts and Telecommunications, China)

0
Ultra-reliable and low-latency communication (URLLC) is proposed as one of the three key services of 5G for Internet of Things (IoT), especially for mission-critical applications. This paper investigates the minimum power of devices in uplink in IoT networks for URLLC. Unmanned aerial vehicles (UAVs) are utilized to assistant the IoT system because they have flexible deployment and high probability to establish line-of-sight (LoS) communication links. First, we formulate a minimum average transmit power problem under the constraints of latency and reliability in modern industry. The deployment of UAVs and device association need to be jointly optimized, making the problem non-linear and non-convex. Then the block error probability which characterizes the reliability is derived under finite blocklength regime and an iteration algorithm is proposed. Additionally, the minimum average transmit power of IoT devices in URLLC is also calculated by deploying different number of UAVs. Simulation results are presented to show that the transmit power can be greatly reduced by appropriately deploying more UAVs or relaxing the tolerance of latency.

Joint Optimization of UAV Trajectory and User Scheduling Based on NOMA Technology

Xuemeng Wu, Zaixue Wei, Zhenqiao Cheng and Xin Zhang (Beijing University of Posts and Telecommunications, China)

0
Unmanned aerial vehicles (UAVs) have been widely used in the past few decades due to their high maneuverability. This paper studies a downlink UAV air-ground wireless network based on non-orthogonal multiple access (NOMA) technology, where a UAV is deployed as an aerial base station to provide periodic service for a group of users. With the purpose of maximizing the minimum sum rate of system in the limited time, an iterative algorithm for jointly optimizing user scheduling and UAV trajectory is proposed. In order to find the optimal users to communicate with, we present a method of user partitioning based on k-Means clustering algorithm and a strategy for selecting subset to schedule on the basis of NOMA technology. The maximum sum rate of edge users in the NOMA-based UAV communication system is also considered. The simulation results are provided to show the optimal UAV trajectories with different objective functions, and to indicate that the NOMA-based UAV system provides the benefits of achieving a better air-ground communication compared to OMA scheme and other benchmark schemes.

Enhancing Cellular Communications for UAVs via Intelligent Reflective Surface

Dong Ma (University of New South Wales, Australia); Ming Ding (Data 61, Australia); Mahbub Hassan (University of New South Wales, Australia)

0
Intelligent reflective surfaces (IRSs) capable of reconfiguring their electromagnetic absorption and reflection properties in real-time are offering unprecedented opportunities to enhance wireless communication experience in challenging environments. In this paper, we analyze the potential of IRS in enhancing cellular communications for UAVs, which currently suffers from poor signal strength due to the down-tilt of base station antennas optimized to serve ground users. We consider deployment of IRS on building walls, which can be remotely configured by cellular base stations to coherently direct the reflected radio waves towards specific UAVs in order to increase their received signal strengths. Using the recently released 3GPP ground-to-air channel models, we analyze the signal gains at UAVs due to the IRS deployments as a function of UAV height as well as various IRS parameters including size, altitude, and distance from base station. Our analysis suggests that even with a small IRS, we can achieve significant signal gain for UAVs flying above the cellular base station. We also find that the maximum gain can be achieved by optimizing the location of IRS including its altitude and distance to BS.

UAV-based Air-to-Ground Channel Modeling for Diverse Environments

Muhammad Usaid Akram, Usama Saeed and Syed Ali Hassan (National University of Sciences and Technology, Pakistan); Haejoon Jung (Incheon National University, Korea (South))

0
In recent years, unmanned aerial vehicles (UAVs) have been deployed in a range of new applications such as remote surveillance, package delivery and relief operations. The existing scenario of next-generation communications systems envisions the use of UAVs as low altitude platforms (LAPs) as one of the enabling technologies of next-gen networks. Telecom operators have been exploring low-altitude UAV-based communications solutions for on-demand deployment. The emerging possibilities of UAVs in air-to-ground (AG) communication necessitate accurate channel models in order to facilitate the design and implementation of such AG links. However, the propagation channels of Pakistan and in general the South Asian region have not been as of yet widely investigated. In this paper, a comprehensive study is presented on the air-to-ground channel parameters along with details of measurement campaigns as well as the limitations of this work and future research directions.

Optimizing Transmission and Propulsion Powers for Flying Base Stations

Mohammadsaleh Nikooroo and Zdenek Becvar (Czech Technical University in Prague, Czech Republic)

0
Unmanned aerial vehicles acting as flying base stations (FlyBSs) have been considered as an efficient tool to enhance capacity of mobile networks and to facilitate communication in emergency cases. The enhancement provided by such network necessitates a dynamic positioning of the FlyBSs with respect to the users. Despite that, the power consumption of the FlyBS remains an important issue to be addressed due to limitations on the capacity of FlyBS's batteries. In this paper, we propose a novel solution combining a transmission power control and the positioning of the FlyBS in order to ensure quality of service to the users while minimizing total consumed power of the FlyBS. We derive a closed-form solution for joint transmission and propulsion power optimization in a single future step. Moreover, we also provide a numerical method to solve the joint propulsion and transmission power optimization problem when a realistic (i.e. inaccurate) prediction of the users' movement is available. According to the simulations, the proposed scheme brings up to 26% of total FlyBS's power saving compared to existing solutions.

Session Chair

Han Seung Jang (Chonnam National University, Korea)

Play Session Recording
Session T1-S27

Massive MIMO 2

Conference
4:00 PM — 5:30 PM KST
Local
May 28 Thu, 3:00 AM — 4:30 AM EDT

Limits of Transmit and Receive Array Gain in Massive MIMO

Tobias Laas (Huawei Technologies Duesseldorf GmbH & Technical University of Munich, Germany); Josef A. Nossek (Technical University of Munich, Germany & Federal University of Ceará, Brazil); Wen Xu (Huawei Technologies Duesseldorf GmbH, Germany)

2
In this paper, we consider the transmit and receive antenna array gain of massive MIMO systems. In particular, we look at their dependence on the number of antennas in the array, and the antenna spacing for uniform linear and uniform circular arrays. It is known that the transmit array gain saturates at a certain antenna spacing, but the receive array gain had not been considered. With our physically consistent analysis based on the Multiport Communication Theory, we show that the receive array gain does not saturate, but that there is a peak at a certain antenna spacing when there is no decoupling network at the receiver. As implementing a decoupling network for massive MIMO would be almost impossible, this is a reasonable assumption. Furthermore, we analyze how the array gain changes depending on the antenna spacing and the size of the antenna array and derive design recommendations.

A Study on Unique-Word based Synchronization for MIMO Systems over Time-Varying Channels

Shahab Ehsanfar (Technische Universität Dresden, Germany); Marwa Chafii (ENSEA, France); Gerhard P. Fettweis (Technische Universität Dresden, Germany)

3
In conventional multicarrier systems, a cyclic prefix (CP) is added to the transmission block in order to protect it from multi-path propagation of the wireless channel. Nonetheless, due to the random nature of the CP, it is usually discarded at the receiver side, and from a synchronization perspective, this energy is wasted. Unique Word (UW) is a promising concept for CP replacement, because, in addition to protecting the signal from multi-path propagation, it allows per-block synchronization. Considering a multiple-input-multiple-output (MIMO) system, the state-of-the-art (SoA) data-aided synchronization approaches are mainly preamble based, while, on the other hand, the synchronization techniques for UW sequences are being applied to single-input-single-output systems in low mobility scenarios. In this paper, we investigate time and frequency synchronization of UW-based MIMO systems in high mobility conditions where the wireless channel is both frequency selective and fast fading. Through theoretical derivations as well as extensive simulations, we show that the proposed UW-based synchronization approach for MIMO outperforms the SoA MIMO synchronization techniques.

ACS-Based Beam Selection for Massive MIMO Interfering Broadcast Channels with Hybrid Precoding

Meng Qi (Shanghai Jiao Tong University, China); Gui Lin (ShangHai JiaoTong University, China); Ling Zhang (Shanghai Jiao Tong University, China)

2
In the next generation of cellular communications, ultra-dense networking is a key to ensuring the coverage of millimeter-wave systems. On the other hand, hybrid precoding (HP) has been recognized as a promising technology for millimeter wave-based massive multiple-input multiple-output (MIMO) systems. However, few research efforts have been invested in handling multi-cell interference with hybrid precoding structure. In this paper, we propose a multi-cell interference processing scheme based on the ant colony system (ACS) method for massive MIMO interfering broadcast channels with hybrid precoding structure. Specifically, we first formulate the beam selection problem in the radio frequency (RF) domain as a traveling problem. Then with the goal of minimizing inter-cell signal-to-leakage-ratio (SLR), an ACS-based algorithm is proposed to provide the RF precoder design for each BS. Meanwhile, in each cell, the baseband combiner of each user is obtained by the singular value decomposition (SVD) method to maximize the corresponding channel gain, and the baseband precoder is provided by zero-forcing (ZF) algorithm to eliminate inter-user interference (IUI). Simulation results show that the proposed scheme can achieve effective beam selection to manage the multi-cell interference under massive MIMO broadcast channels, and the advantages of the proposed scheme in improving the sum rate for multi-cell systems compared with existing schemes.

Max-Min Fair Wireless-Powered Cell-Free Massive MIMO for Uncorrelated Rician Fading Channels

Özlem Tuğfe Demir and Emil Björnson (Linköping University, Sweden)

1
This paper considers cell-free massive multiple-input multiple-output systems where the multiple-antenna access points (APs) assist the single-antenna user equipments (UEs) by wireless power transfer. The UEs utilize the energy harvested in the downlink to transmit uplink pilot and information signals to the APs. We consider practical Rician fading with the line- of-sight components of the channels being phase-shifted in each coherence block. The uplink spectral efficiency (SE) is derived for this model and the max-min fairness problem is considered where the optimization variables are the AP and UE power control coefficients together with the large-scale fading decoding vectors. The objective is to maximize the minimum SE of the users under APs' and UEs' transmission power constraints. An alternating optimization algorithm is proposed for the solution of the highly-coupled non-convex problem.

Low Complexity Iterative Parallel Interference Cancellation Algorithms for Massive MIMO System

Bin Shen and Hebiao Wu (Chongqing University of Posts and Telecommunications (CQUPT), China); Shufeng Zhao and Taiping Cui (Chongqing University of Posts and Telecommunications, China)

0
Low complexity iterative parallel interference cancellation (IPIC) algorithms under hard decision and soft output schemes are proposed for uplink multi-user massive MIMO systems in this paper. By means of circumventing the matrix inversion operations demanded by the conventional MMSE criterion based detection algorithm, the proposed IPIC algorithms reduce the complexity by an order of magnitude. Meanwhile, noise-prediction aided IPIC (NP-IPIC) algorithm is proposed to further improve the detection performance. Considering the residual inter-antenna interference, we propose a low-complexity soft output based IPIC (S-IPIC) detection algorithm as well. Analysis and simulations show that the complexity of the proposed signal detection algorithms is much lower, compared with the MMSE detection algorithm. With only a small number of detection iterations, the proposed algorithms achieve their performance quite close to or even surpassing that of the MMSE algorithm.

Session Chair

Junil Choi (KAIST, Korea (South))

Play Session Recording
Session T1-S28

Coding Scheme 2

Conference
4:00 PM — 5:30 PM KST
Local
May 28 Thu, 3:00 AM — 4:30 AM EDT

On the Error Probability of Interference Exploitation Precoding with Power Allocation

Abdelhamid Salem (UCL, United Kingdom (Great Britain)); Christos Masouros (University College London, United Kingdom (Great Britain))

0
In this paper, we analyze the performance of constructive interference (CI) precoding in downlink multi-user multiple-input single-output (MU-MISO) systems with phase- shift-keying (PSK) signals. A new closed-form expression is derived for the moment generating function (MGF) of the received signal-to-noise-ratio (SNR). Then, the MGF is used to calculate the average symbol error probability (SEP) for the CI technique. In light of this, new exact analytical expression and very accurate asymptotic expression for the average SEP are presented. Based on the new SEP expressions, a power allocation scheme to minimize the sum SEPs (Min-Sum) is investigated, and analytical expression of the power allocation factors is derived. The numerical results show that, the CI precoding yields superior performance over conventional interference suppression precoding techniques in terms of SEP. Furthermore, the Min-Sum power allocation scheme provides additional up to 10dB gains in the transmit SNR compared to equal power allocation technique.

A Low-Complexity Dual Trellis Decoding Algorithm for High-Rate Convolutional Codes

Vinh Hoang Son Le, Charbel Abdel Nour and Catherine Douillard (IMT Atlantique, France); Emmanuel Boutillon (Université de Bretagne Sud, France)

2
Decoding using the dual trellis is considered as a potential technique to increase the throughput of soft-input soft-output decoders for high coding rate convolutional codes. However, the dual Log-MAP algorithm suffers from a high decoding complexity. More specifically, the source of complexity comes from the soft-output unit, which has to handle a high number of extrinsic values in parallel. In this paper, we present a new low-complexity sub-optimal decoding algorithm using the dual trellis, namely the dual Max-Log-MAP algorithm, suited for high coding rate convolutional codes. A complexity analysis and simulation results are provided to compare the dual MaxLog-MAP and the dual Log-MAP algorithms. Despite a minor loss of about 0.2 dB in performance, the dual Max-Log-MAP algorithm significantly reduces the decoder complexity and makes it a first-choice algorithm for high-throughput high-rate decoding of convolutional and turbo codes.

A Modified Rejection-Based Architecture to Find the First Two Minima in Min-Sum-Based LDPC Decoders

Alireza Hasani (Brandenburg University of Technology Cottbus-Senftenberg & IHP GmbH - Innovations for High Performance Microelectronics, Germany); Lukasz Lopacinski (IHP, Germany); Steffen Büchner (Brandenburgische Technische Universität Cottbus-Senftenberg, Germany); Jörg Nolte (BTU Cottbus, Germany); Rolf Kraemer (IHP Microelectronics, Frankfurt/Oder & BTU-Cottbus, Germany)

1
One of the essential elements of min-sum low- density parity-check (LDPC) decoders is to find the first two minima between the binary messages arriving in the check nodes along with the index of the minimum which are altogether used to compute the messages for sending back to the neighboring variable nodes. The main techniques for this task are tree-based and bit-serial architectures. The latest tree-based architecture, known as rejection-based scheme finds the first two minima and the binary index of the minimum with higher speed than the previous tree-based methods. However, in min-sum LDPC decoders, having one-hot sequence of the minimum of the messages is preferred as it has implementation benefits. In this paper, we modify the existing rejection-based technique to yield the one-hot sequence instead of the binary representation of the minimum index. The proposed modification doesn't cause any latency in the operation of the module. We also provide the results of the implementation of the modified rejection-based technique and the bit-serial architecture, conducted on a Xilinx Virtex-7 FPGA. The two major architectures are compared in terms of latency, maximum clock frequency, area and power.

Space-Time Coding for Orbital Angular Momentum Multiplexed Free-Space Optical Systems

El Mehdi Amhoud (Mohammed VI Polytechnic University, Morocco); Ghaya Rekaya-Ben Othman (TELECOM ParisTech, France)

1
Communication using orbital angular momentum (OAM) modes has recently received a considerable interest in free space optical (FSO) communications. Propagating OAM modes through free space may be subject to atmospheric turbulence (AT) distortions that cause intermodal crosstalk and power disparities between OAM modes. In this paper, we are interested in multiple-input multiple-output (MIMO) coherent FSO communication systems using OAM multiplexing. We propose space-time (ST) coding at the transmitter to enhance the bit error rate (BER) performance against atmospheric turbulence. Through numerical simulations, we show performance improvement thanks to ST coded schemes for different MIMO dimensions. Furthermore, we derive an analytical expression for the error probability upper bound of the ST coded OAM FSO channel affected by atmospheric turbulence. The theoretical error probability is compared with Monte Carlo simulations and a good agreement is observed.

Space-Time Waveform Coding for Joint Radar and Wireless Communications (RadCom) Applications

Jan Mietzner (Hamburg University of Applied Sciences (HAW), Germany); Avik Santra (Infineon Technologies AG, Germany)

1
We propose a novel space-time waveform coding (STWC) scheme for joint radar and wireless communications (RadCom). In particular, we consider a frequency- modulated continuous-wave (FMCW) multiple-input multipleoutput (MIMO) radar for near-range to medium-range radar applications. In order to establish the required orthogonal transmit signals, up- and down-chirp FMCW waveforms are combined with Alamouti space-time coding across two transmit antennas. We demonstrate that, from a radar perspective, the cross- ambiguity function is improved significantly by the orthogonal Alamouti code, while the FMCW waveforms ensure robustness in the presence of Doppler shifts. Regarding the communications part, the generic orthogonality of the Alamouti code allows us to embed random information symbols within the radar signal, enabling wireless communications in the 100 kb/s regime. To this end, we propose a suitable communications receiver algorithm for multiple antennas with corresponding maximum-ratio combining, which is able to extract the embedded information symbols while acquiring spatial diversity gains.

Session Chair

SongNam Hong (Ajou University, Korea (South))

Play Session Recording
Session T1-S29

Transceiver Design

Conference
4:00 PM — 5:30 PM KST
Local
May 28 Thu, 3:00 AM — 4:30 AM EDT

A Distance-Detection Receiver for Ambient Backscatter Communications with MPSK RF Source

Youyou Zhang (UESTC, China); Ying-Chang Liang (University of Electronic Science and Technology of China, China); Pooi-Yuen Kam (National University of Singapore, Singapore)

1
Ambient Backscatter Communication (AmBC) is a promising technology for green IoT, which overcomes the energy, cost and spectrum resource shortage challenges. In AmBC, the weak backscatter link strength caused by the double-fading is a big challenge for IoT device symbol detection. This paper focuses on receiver design with the MPSK RF source symbol. Most previous works have not considered the issue of channel estimation that is very important for wireless communications. We focus on precisely estimating the channels at each of the AmBC receiving antennas, in particular on resolving the phase ambiguities in the channel estimates. The proposed channel estimator is simple to implement, and it makes use of both the pilot and the data symbols of the RF source to eliminate quadrant ambiguity and enhance the estimation accuracy. To keep the receiver complexity low while maintaining good performance, we propose a novel distance detector (DD) that makes its decision in each IoT symbol interval based on which of the calibrated channel estimates the current channel estimate is closer to in Euclidean distance. What is more, we propose two modified distance detection methods to enhance the bit error rate (BER) performance. Finally, extensive numerical results show that the proposed distance detection method achieves comparable performance as the optimal detector with perfect channel state information (CSI).

On the Information Transfer Rate of SPAD Arrays

Elham Sarbazi and Majid Safari (University of Edinburgh, United Kingdom (Great Britain)); Harald Haas (The University of Edinburgh, United Kingdom (Great Britain))

1
In this paper the information transfer rate of a single-photon avalanche diode (SPAD) array is investigated. The SPAD array is modelled as a discrete-time Gaussian channel with signal-dependent mean and variance. The SPAD dead time is a parameter which affects the extent of this signal dependency. The SPAD array channel capacity and the properties of the capacity- achieving input distributions are studied. Using a numerical algorithm, the capacity and the optimal input distributions subject to peak and average power constraints are obtained for various array sizes, dead times and background count levels.

Defeating Smart and Reactive Jammers with Unlimited Power

Huynh Van Nguyen (University of Technology Sydney, Australia); Hoang Thai Dinh (University of Technology Sydney (UTS), Australia); Diep N. Nguyen and Eryk Dutkiewicz (University of Technology Sydney, Australia); Markus Dominik Mueck (Intel Deutschland GmbH, Germany)

1
Among all wireless jammers, dealing with reactive ones is most challenging. This kind of jammer attacks the channel whenever it detects transmission from legitimate radios. With recent advances in self-interference suppression or in-band full- duplex radios, a reactive jammer can jam and simultaneously sense/discern/detect the legitimate transmission. Such a jammer is referred to as a smart reactive jammer. However, all existing solutions, e.g., frequency hopping and rate adaptation, cannot effectively deal with this type of jammer. This is because a smart reactive jammer with sufficient power budget can theoretically jam most, if not all, frequency channels at sufficiently high power. This work proposes to augment the transmitter with an ambient backscatter tag. Specifically, when the jammer attacks the channel, the transmitter deceives it by continuing to transmit data to attract the jammer while the tag backscatters data based on both the jamming signals and active signals from the jammer and transmitter, respectively. However, backscattering signals from multiple radio sources results in a high bit error rate (BER). Thus, we propose to use multiple antennas at the receiver. The theoretical analysis and simulation results show that by using multiple antennas at the receiver, the BER and hence the throughput of the system can be significantly improved. More importantly, we demonstrate that with our proposed solutions, the average throughput increases and the BER decreases when the jammer attacks with higher power levels. We believe that this is the first anti-jamming solution that can cope effectively with a high- or even unlimited-power jammers.

Filter Bank Multicarrier Transmission Based on the Discrete Hartley Transform

Chin-Liang Wang, Hong-Shiuann Pan and Chia-Tung Tuan (National Tsing Hua University, Taiwan)

0
This paper presents a new filter bank multicarrier (FBMC) transmission scheme that uses the real-valued discrete Hartley transform (DHT) for both multicarrier modulation and demodulation, rather than the complex-valued inverse discrete Fourier transform (IDFT) and DFT for multicarrier modulation and demodulation respectively in conventional FBMC systems. The DHT-FBMC scheme is with quadrature amplitude modulation (QAM) and adopts a pair of orthogonal or nearly orthogonal pulse shaping filters, one for even-numbered subcarriers and the other for odd-numbered subcarriers, to mitigate self-interference. The proposed method potentially has advantages in terms of performance and implementation, due to the fact that it possesses some distinct channel diversity on mirror-symmetrical subcarriers and involves identical real-valued transform operations at the transmitter and receiver. In contrast to existing DFT-FBMC systems using QAM or offset QAM (OQAM), the DHT-FBMC scheme using QAM achieves better bit-error-rate performance with comparable or reduced computational complexity.

Distributed Detection with Non-Identical Sensors: Fusion in the Air or at the Receiver?

Smruti Ranjan Ranjan Panigrahi (University of Gävle & KTH Royal Institute of Technology, Sweden); Niclas Björsell (University of Gävle, Sweden); Mats Bengtsson (KTH Royal Institute of Technology, Sweden)

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In this research paper, fusion in the air (FIA) and fusion at the receiver (FAR) - two different approaches of multi- hypotheses distributed detection for wireless sensor networks with decision fusion center (DFC) - are investigated. The DFC is equipped with multiple antennas, whereas each of the sensors has a single antenna. The performance of these schemes is evaluated in two different scenarios; with identical sensors and non-identical sensors, in terms of their detection capabilities. For a global event, identical sensors observe an equal number of hypotheses, whereas the number of hypotheses detected by the non-identical sensors can be different. When all the sensors in the network are identical, the FIA based technique has a higher detection probability in transmit power constrained situations. However, the FAR scheme performs better when the transmit power budget is higher. Additionally, in the network with non-identical wireless sensors, the FAR based technique is unable to exploit the benefits from the local decisions of the low capability sensors. Therefore the FAR scheme has a lower detection probability than the FIA based approach.

Session Chair

Jun Won Choi (Hanyang University, Korea (South))

Play Session Recording
Session T3-S26

UAV (Unmanned Aerial Vehicle) 2

Conference
4:00 PM — 5:30 PM KST
Local
May 28 Thu, 3:00 AM — 4:30 AM EDT

Reducing Energy Consumed by Repositioning of Flying Base Stations Serving Mobile Users

Zdenek Becvar, Pavel Mach and Mohammadsaleh Nikooroo (Czech Technical University in Prague, Czech Republic)

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Unmanned Aerial Vehicles (UAVs), acting as flying base stations (FlyBSs), are seen as a promising solution for future mobile networks, as the FlyBSs can serve space and time varying heterogeneous traffic in areas where deployment of conventional static base stations is uneconomical or infeasible. However, an energy consumption of the FlyBSs is a critical issue. In this paper, we target a scenario where the FlyBSs serve slowly moving users, e.g., visitors of an outdoor music festival or a performance. In such scenario, rotary-wing FlyBSs are not efficient due to a high energy consumption while not moving (given by an effect of a "helicopter" dynamics). Hence, we consider small airships or balloons. We develop a closed-form solution that determines new positions of the FlyBSs so that the energy consumption for a movement of the FlyBSs is reduced significantly (by 45-94% depending on the number of deployed FlyBSs) while sum capacity of the users is decreased only marginally (less than 1% for before-mentioned energy savings). Moreover, the proposed solution does not require any prediction of users' movement, thus, it is not affected by the prediction error or uncertainty of the users' behavior.

Efficient Deployment of UAV-powered Sensors for Optimal Coverage and Connectivity

Oktay Cetinkaya and Geoff V Merrett (University of Southampton, United Kingdom (Great Britain))

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The Internet of Things (IoT) digitizes the physical world with wireless devices sensing their surroundings and delivering periodic notifications of parameters they are monitoring. However, this operation is bound by finite-capacity batteries, in which replenishment is practically infeasible due to the envisioned size of the IoT networks. By also considering the autonomous and self-sufficient service vision of the IoT paradigm, the need for novel approaches overcoming the energy constraints is evident. Here, unmanned aerial vehicles (UAVs) come into prominence. The UAVs can remotely energize wireless devices, via wireless power transfer (WPT), and thus guarantee reliable sensing coverage as well as longevity in the IoT domain. However, this can be only achieved by the precise alignment of both UAVs and wireless devices. Thus, this paper presents an efficient deployment strategy based on the circle packing problem, in which a lower- bound for the required number of wireless devices achieving optimal coverage is derived. The analysis, based on empirical measurements, reveals the design considerations for an energy harvesting (EH)-aided UAV scenario with regard to Federal Communications Commission (FCC) regulations, power consumption of wireless devices, and reporting frequency requirements of the IoT applications. Our results elaborate on a number of trade-offs, based on UAV, device, and medium characteristics, and provide realistic guidelines, achieving optimal coverage while meeting application requirements.

Multi-UAV Collaborative Data Collection for IoT Devices Powered by Battery

Yue Wang (Beijing University of Posts and Telecommunication, China); Xiang Ming Wen (Beijing University of posts and telecommunications, China); Zhiqun Hu (Hubei University, China); Zhaoming Lu (BUPT, China); Jiansong Miao and Chuanzhi Sun (Beijing University of Posts and Telecommunications, China); Hang Qi (Beijing University of Posts and Telecommunications & BUPT, China)

1
Due to the limited energy of the Internet of Things (IoT) device, unmanned aerial vehicle (UAV) as a mobile fusion center can effectively prolong the lifetime of IoT device via supporting communication with the device directly. Moreover, since UAV's energy constrained, it will be a good measure to take multiple UAVs to collect data from devices in large areas. In this paper, we investigate multi-UAV collaborative data collection system, where multiple UAVs collect data from two- dimensional distributed devices on flying mode or hovering mode. The objective is to minimize UAVs' total flight time while allowing each device to complete data upload successfully with limited energy. To this end, firstly, a cell partition based on Voronoi diagram is used to allocate the collection areas of each UAV. Then, in each associated area, UAV determines the whole trajectory to serve devices. Lastly, given load requirement of ground devices and energy limitation, the optimal data collection mode of each device is decided to minimize flight time of each UAV. Simulation results show that the proposed multi-UAV data collection scheme can shorten collection task completion time significantly.

Resource Allocation for UAV Assisted Wireless Networks with QoS Constraints

Weihang Ding (Kings College London, China); Zhaohui Yang (King's College London, United Kingdom (Great Britain)); Mingzhe Chen (Princeton University, USA); Jiancao Hou and Mohammad Shikh-Bahaei (King's College London, United Kingdom (Great Britain))

1
For crowded and hotspot area, unmanned aerial vehicles (UAVs) are usually deployed to increase the coverage rate. In the considered model, there are three types of services for UAV assisted communication: control message, non-realtime communication, and real-time communication, which can cover most of the actual demands of users in a UAV assisted communication system. A bandwidth allocation problem is considered to minimize the total energy consumption of this system while satisfying the requirements. Two techniques are introduced to enhance the performance of the system. The first method is to categorize the ground users into multiple user groups and offer each group a unique RF channel with different bandwidth. The second method is to deploy more than one UAVs in the system. Bandwidth optimization in each scheme is proved to be a convex problem. Simulation results show the superiority of the proposed schemes in terms of energy consumption.

Trajectory Design for Energy Harvesting UAV Networks: A Foraging Approach

Xuanlin Liu (Beijing University of Posts and Telecommunications, China); Mingzhe Chen (Princeton University, USA); Sihua Wang (Beijing University of Posts and Telecommunications, China); Walid Saad (Virginia Tech, USA); Changchuan Yin (Beijing University of Posts and Telecommunications, China)

1
In this paper, the problem of trajectory design for energy harvesting unmanned aerial vehicles (UAVs) is studied. In the considered model, the UAV acts as a moving base station to serve the ground users, while collecting energy from the charging stations located at the center of a user group. Meanwhile, to serve ground users and harvest energy, the UAV must be examined and repaired regularly. In consequence, it is necessary to optimize the trajectory design of the UAV while jointly considering the maintenance costs, the number of users that are served by the UAV, and the energy consumption and harvesting. To capture the relationship among these factors, we first model the completion of service and the harvested energy as reward, and the energy consumption during the deployment as cost. Then, the deployment profitability is defined as the reward to the cost of the UAV trajectory. Based on this definition, the trajectory design problem is formulated as an optimization problem whose goal is to maximize the deployment profitabilit