Bi-directional relay for coded cooperation

Abstract

Coded cooperation (CC) is a popular method used to mitigate slow fading in wireless communication. In CC, a pair of users help each other with relaying part of partner``s data is investigated to extend wireless channel reach by cooperative diversity. Basing on that basic principle and taking advantage of a bidirectional property of data flows, instead of transmitting the each packet from each user in the second phase of CC, we propose to broadcast a joint packet with XOR-gated information of the two second packets from both users. Moreover, we have to solve some problems when using CC for the bi-directional transmission. The method is called Bi-directional relay for coded cooperation (BiCC). The throughput is increased and the quality is also improved based on mathematical analysis and simulation. To follow up, we propose a multi-mode version of BiCC. This method even gives a higher throughput than BiCC but requires some signaling between the nodes. We show the performance comparison between Multi-mode BiCC (mmBiCC), BiCC and CC. Algorithms to implement mmBiCC are also provided. On the other hand, partner selection is a process that must be carried out before the cooperation occurs. We propose two methods of partner selection called Most Most Shadowed User Priority and Maximum Average User-User Shadow Reciprocal Factor. We compare the performances of the two methods as well as analyse advantage and disadvantages when used with BiCC and Multi-mode BiCC.