Performance of Joint Channel and Physical Network Coding Based on Alamouti STBC

This work considers the protograph-coded physical network coding (PNC) based on Alamouti space-time block coding (STBC) over Nakagami-fading two-way relay channels, in which both the two sources and relay possess two antennas. We first propose a novel precoding scheme at the two sources so as to implement the iterative decoder efficiently at the relay. We further address a simplified updating rule of the log-likelihood-ratio (LLR) in such a decoder. Based on the simplified LLR-updating rule and Gaussian approximation, we analyze the theoretical bit-error-rate (BER) of the system, which is shown to be consistent with the decoding thresholds and simulated results. Moreover, the theoretical analysis has lower computational complexity than the protograph extrinsic information transfer (PEXIT) algorithm. Consequently, the analysis not only provides a simple way to evaluate the error performance but also facilitates the design of the joint channel-and-PNC (JCNC) in wireless communication scenarios.Comment: 6 pages, 4 figures, accpete

Physical-layer network coding and precoding for end nodes using Alamouti scheme

Conference Name:2012 International Symposium on Communications and Information Technologies, ISCIT 2012. Conference Address: Gold Coast, QLD, Australia. Time:October 2, 2012 - October 5, 2012.This paper proposes a novel STBC-based transmit diversity scheme for physical-layer network coding (PNC) aided two-way relay networks, where two end nodes are equipped with two transmit-antenna. To directly decode network-coded signals from the received superimposed signals at the relay, the two end nodes in this proposed system use reciprocal channel state information (CSI) to precode their respective transmitted signals before STC coding. The corresponding maximum a-posterior probability (MAP) and an approximated threshold-decision (TD) decodings are introduced, based on which the relay can remain the same transmit diversity gain in the multiple-access (MA) stage as the conventional STBC-based network-coding (STBC-NC) scheme. Considering BPSK and QPSK used at the end nodes, simulation results illustrate that the proposed STBC-PNC shows symbol error rate (SER) performance no worse than the STBC-NC, and significantly outperforms the single-input-single-output (SISO)-PNC and the previous PNC-aided STBC schemes. 漏 2012 IEEE