Cooperative Medium Access Control in Wireless Networks: The Two-Hop Case

Cooperative communication has been recently proposed as a powerful means to improve network performance in wireless networks. However, most existing work focuses solely on one-hop source-destination cooperation. In this paper, we propose a novel cooperative MAC mechanism that is specially designed for two-hop cooperation communications where the source node and the destination node cannot hear each other directly. In this case, cooperative communication is operated in a two-hop manner and transmit-diversity is achieved by the reception of the same data packet forwarded through multiple relays towards a single destination. The proposed scheme employs an efficient relay selection algorithm to maximize cooperation benefits and can avoid collision effectively. Numerical results show that compared with the original non-cooperative protocol, significant throughput improvement and access delay reduction have been achieved with our two-hop cooperative MAC mechanism.