Main Conference

Session OPNTH: Opening Session on Thursday
Session KNTH-S1: Keynote Session KNTH-S2: Keynote
Session T1-S20: Massive MIMO 1 Session T1-S21: Coding Scheme 1 Session T1-S22: Performance Analysis 1 Session T1-S23: Machine-Type Communications Session T1-S24: Polar Code Session T1-S25: Performance Analysis 2 Session T1-S26: Hardware and Implementation Session T1-S27: Massive MIMO 2 Session T1-S28: Coding Scheme 2 Session T1-S29: Transceiver Design
Session T2-S7: Scheduling
Session T3-S20: UAV (Unmanned Aerial Vehicle) 1 Session T3-S21: Security and Privacy 1 Session T3-S22: Resource Management and Optimization 1 Session T3-S23: Mobility and Handoff Management Session T3-S24: Rate Control and Transport Protocol Session T3-S25: Resource Management and Optimization 2 Session T3-S26: UAV (Unmanned Aerial Vehicle) 2 Session T3-S27: Security and Privacy 2 Session T3-S28: Resource Management and Optimization 3 Session T3-S29: Multi-Connectivity
Session T4-S10: Crowdsourcing and Incentive Mechanism Session T4-S9: Recognition and Prediction Session T4-S11: Low Power and IoT Session T4-S12: Communications with UAVs Session T4-S13: Hybrid Satellite Networks Session T4-S14: mmWave and Optical Wireless

Track 1 – Phy & Fundamentals

Session T1-S20

Massive MIMO 1

Conference
10:40 AM — 12:10 PM KST
Local
May 27 Wed, 6:40 PM — 8:10 PM PDT

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, 6:40 PM — 8:10 PM PDT

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, 6:40 PM — 8:10 PM PDT

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 T1-S23

Machine-Type Communications

Conference
2:00 PM — 3:30 PM KST
Local
May 27 Wed, 10:00 PM — 11:30 PM PDT

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 27 Wed, 10:00 PM — 11:30 PM PDT

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 27 Wed, 10:00 PM — 11:30 PM PDT

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 27 Wed, 10:00 PM — 11:30 PM PDT

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 T1-S27

Massive MIMO 2

Conference
4:00 PM — 5:30 PM KST
Local
May 28 Thu, 12:00 AM — 1:30 AM PDT

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))

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Session T1-S28

Coding Scheme 2

Conference
4:00 PM — 5:30 PM KST
Local
May 28 Thu, 12:00 AM — 1:30 AM PDT

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))

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Session T1-S29

Transceiver Design

Conference
4:00 PM — 5:30 PM KST
Local
May 28 Thu, 12:00 AM — 1:30 AM PDT

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)

0
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))

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