Opportunistic cooperation and selective forwarding, a virtual MIMO scheme for wireless networks

Multipath fading greatly degrades system performance of wireless networks. Conventionally diversity is introduced to mitigate fading. In this paper we study space diversity in multi-hop wireless networks under power constraints. Point-to-point links are extended to group-to-group virtual MIMO links. Then we propose a cross-layer design of MAC and routing that exploits opportunistic cooperation and selective forwarding (OCSF). Packets are forwarded around the pre-calculated anchor route and the proposed OCSF scheme enables local post selection of both transmitter and forwarder according to channel state information. Simulation results confirm that OCSF outperforms existing schemes that utilize distributed space-time coding or selection diversity.