Abstract:

An opportunistic cooperative network-coding scheme based on space-time coding (OCNC) is proposed for combining channel fading and improving resource efficiency and network throughput. Focusing on the bi-directional traffic flows in wireless cooperative relaying network, the OCNC schemes, termed as 3-step and 2-step schemes respectively is grouped, and their bit error probabilities and the network-coding gain is developed and analyzed. The numerical results show that, in contrast to traditional scheme, a full diversity (i.e. K-order diversity in case of K relay nodes) is achieved by both OCNC schemes and asymptotical 4/3 and 2 times of network-coding gain are obtained by 3-step and 2-step OCNC schemes respectively. In addition, because of opportunistic relaying of multiple nodes, the network-coding gain of OCNC is more considerable in the medium signal-to-noise ratio (SNR) range.

Key words: cooperative diversity, network coding, bit error probability, gain of network coding