Multiple-access relaying with network coding: iterative network/channel decoding with imperfect CSI

Abstract

In this paper, we study the performance of the four-node multiple-access relay channel with binary Network Coding (NC) in various Rayleigh fading scenarios. In particular, two relay protocols, decode-and-forward (DF) and demodulate-and-forward (DMF) are considered. In the first case, channel decoding is performed at the relay before NC and forwarding. In the second case, only demodulation is performed at the relay. The contributions of the paper are as follows: (1) two joint network/channel decoding (JNCD) algorithms, which take into account possible decoding error at the relay, are developed in both DF and DMF relay protocols; (2) both perfect channel state information (CSI) and imperfect CSI at receivers are studied. In addition, we propose a practical method to forward the relays error characterization to the destination (quantization of the BER). This results in a fully practical scheme. (3) We show by simulation that the number of pilot symbols only affects the coding gain but not the diversity order, and that quantization accuracy affects both coding gain and diversity order. Moreover, when compared with the recent results using DMF protocol, our proposed DF protocol algorithm shows an improvement of 4 dB in fully interleaved Rayleigh fading channels and 0.7 dB in block Rayleigh fading channels.

Performance Analysis of Network Coded Cooperation with Channel Coding and Adaptive DF-Based Relaying in Rayleigh Fading Channels

“…In particular, each source can apply it independently of the others. As for the sources that belong to , (3) might be solved by applying iterative decoding methods, as described in [9]. These methods, however, have two limitations: they are sub-optimal and they are not conveniently formulated for mathematical analysis and for identifying the achievable diversity order.…”

“…Since the trellis of the super code consists of all the combinations of the trellis states of the sources, the complexity of the proposed decoder exponentially increases with the number of sources . Although it is more computationally intensive than the iterative decoding algorithms described in [9], it allows us to analyze the BER of Coded-NCC systems.…”

“…By direct inspection of (8) and (9), we note that a diversity order equal to corresponds to . By inserting (9) and (8) in (6) and (5), an upper bound and an approximation for the BER of the source can be obtained. It is worth noting that, even though the output weight in (6) can be infinity, the BER is usually determined by a few first values of [14].…”

“…Iterative Network and Channel Decoding (INCD) is an active field of research and various authors have investigated its BER performance. For example, the performance of binary NC with Convolutional Coding (CC) is studied in [8], [9] for propagation over quasi-static block fading channels. The generalization to non-binary NC is available in [10].…”

Network Coding Based Multiple-Hop Efficient Transmission Method for Multiple-User Multiple-Relay Networks

“…Cooperative communication employing network coding has been widely studied in recent years. In [2], simple binary network coding scheme is used for two-user with the assist of one relay. However, the approach based on XOR network coding may not be optimal in multiple-user scenario.…”