Optimized constellations for two-way wireless relaying with physical network coding
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TLDR
The proposed modulation scheme can significantly improve end-to-end throughput for two-way relaying systems and is applicable to a relaying system using higher-level modulations of 16QAM in the MA stage.Abstract:
We investigate modulation schemes optimized for two-way wireless relaying systems, for which network coding is employed at the physical layer. We consider network coding based on denoise-and-forward (DNF) protocol, which consists of two stages: multiple access (MA) stage, where two terminals transmit simultaneously towards a relay, and broadcast (BC) stage, where the relay transmits towards the both terminals. We introduce a design principle of modulation and network coding, considering the superposed constellations during the MA stage. For the case of QPSK modulations at the MA stage, we show that QPSK constellations with an exclusive-or (XOR) network coding do not always offer the best transmission for the BC stage, and that there are several channel conditions in which unconventional 5-ary constellations lead to a better throughput performance. Through the use of sphere packing, we optimize the constellation for such an irregular network coding. We further discuss the design issue of the modulation in the case when the relay exploits diversity receptions such as multiple-antenna diversity and path diversity in frequency-selective fading. In addition, we apply our design strategy to a relaying system using higher-level modulations of 16QAM in the MA stage. Performance evaluations confirm that the proposed scheme can significantly improve end-to-end throughput for two-way relaying systems.read more
Citations
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Proceedings ArticleDOI
On the performance of two-way amplify-and-forward relaying in the presence of co-channel interferences
Salama S. Ikki,Sonia Aissa +1 more
TL;DR: This paper studies the error performance of two-way amplify-and-forward relaying over independent but not necessarily identically distributed Rayleigh fading channels, in the presence of co-channel interfering signals affecting the network nodes.
Proceedings ArticleDOI
Constellation Mapping for Physical-Layer Network Coding with M-QAM Modulation
TL;DR: In this paper, the authors considered DNF-based PNC with M-ary quadrature amplitude modulation (MQAM) and proposed a mapping scheme that maps the superposed M-QAM signal to coded symbols.
Journal ArticleDOI
Interference-Limited Two-Way DF Relaying: Symbol-Error-Rate Analysis and Comparison
TL;DR: The results show that the TWR protocol where the terminals employ selection combining on the received signals from the relay and direct links can achieve good tradeoff between the average symbol-error-rate performance and computational complexity at the terminals.
Journal ArticleDOI
Two-Way Filter-and-Forward Beamforming for Frequency-Selective Channels
TL;DR: This paper considers filter-and-forward beamforming (FF-BF) for two-way relay networks employing single-carrier transmission over frequency-selective channels and establishes an upper and an achievable lower bound for the max-min problem and an exact solution for the sum MSE problem.
Journal ArticleDOI
Pairwise Check Decoding for LDPC Coded Two-Way Relay Block Fading Channels
TL;DR: A new solution for joint network coding and channel decoding at the relay, called pairwise check decoding (PCD), for low-density parity-check (LDPC) coded TWR system over block fading channels, and the minimum correlation optimization (MCO) for selecting the better check-relation-tabs is proposed.
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