Performance Analysis of Soft Information Cooperation in Bi-Directional Networks

In this paper, we propose the soft information cooperation scheme in the bi-directional wireless relay networks.We first compute the Log-Likelihood ratio (LLR), referred to as the soft information of relay received signal in Rayleigh fading channel, and then propose an efficient LLR-based network coding scheme. Moreover, for computational simplicity, we optimize the soft information cooperation by the defined self soft information at terminals. In addition, we analyze the system performance in terms of generalized signal-to-noise ratio (GSNR), which is shown to be an efficient metric to reveal the BER performance, for one-relay and multi-relay cases. The simulation results show that the soft information cooperation scheme outperforms the traditional amplify-and-forward (AF), decode-and-forward (DF) and compress-and- forward (CF) protocols in terms of GSNR and bit- error rate (BER) in the low-SNR regime.