A Cooperative MAC Protocol for Ad Hoc Wireless Networks

Cooperative communications fully leverages the broadcast nature of the wireless channel and spatial diversity, thereby achieving tremendous improvements in system capacity and delay. By enabling additional collaboration from stations that otherwise will not directly participate in the transmission, cooperative communications ushers in a new design paradigm for wireless communications. In this paper, we extend a cooperative MAC protocol called CoopMAC into the ad hoc network environment. The new protocol is based on the idea of involving in an ongoing communication an intermediate station that is located between the transmitter and the receiver. The intermediate station acts as a helper and forwards to the destination the traffic it receives from the source. Thus, a slow one-hop transmission is transformed into a faster two-hop transmission, thereby decreasing the transmission time for the traffic being handled. Extensive simulations in a large scale wireless ad-hoc network (150 stations) show that CoopMAC significantly improves the ad hoc network performance in terms of throughput and delay, and indicate how such cooperative schemes can boost the performance of traditional solutions (e.g., IEEE 802.11)