Optimized constellations for two-way wireless relaying with physical network coding
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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Journal ArticleDOI
On Non-Binary Constellations for Channel-Coded Physical-Layer Network Coding
Zahra Faraji-Dana,Patrick Mitran +1 more
TL;DR: Different mappings between \mathbb{F} and the PSK constellation are compared, and it is proved that many have identical performance in terms of frame error rate (FER), and the ternary constellation has the best FER performance among all considered cases.
Proceedings ArticleDOI
Wireless bidirectional relaying and Latin Squares
TL;DR: In this article, the authors considered the design of modulation schemes for the physical layer network-coded two-way relaying scenario with the protocol which employs two phases: multiple access (MA) Phase and broadcast (BC) Phase.
Journal ArticleDOI
Symbol and Bit Mapping Optimization for Physical-Layer Network Coding with Pulse Amplitude Modulation
TL;DR: A two-way relay network in which two users exchange messages through a single relay using a physical-layer network coding (PNC) based protocol is considered, showing that the optimal symbol/bit mappings depend on the signal-to-noise ratio (SNR) of the channel and the modulation scheme.
Journal ArticleDOI
Multilevel Coding Schemes for Compute-and-Forward With Flexible Decoding
Brett Hern,Krishna R. Narayanan +1 more
TL;DR: Numerical results demonstrate that the flexibility afforded by the proposed scheme results in substantially higher rates than those achievable by always using a fixed function or considering only linear functions over higher order fields.
Journal ArticleDOI
Beamforming-based physical layer network coding for non-regenerative multi-way relaying
Aditya Umbu Tana Amah,Anja Klein +1 more
TL;DR: The optimum transceive beamforming maximising the sum rate of non-regenerative multi-way relaying is addressed and it is shown that analog network coded transmission outperforms multiplexing transmission.
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