A rate-adaptive cooperative MAC protocol based on RTS/CTS scheme for MANETs

In this paper we propose a novel relay-enabled MAC protocol based on IEEE 802.11 RTS/CTS scheme for MANETs. The protocol enable the middle node lies between the source and destination to decide whether to relay for them adaptively based on the current channel state information (CSI). Because the channel with better quality can transmit data with higher rate, and distance is one of the primary factors that determine wireless channel quality, the throughput will be greatly improved if there is a higher rate supporting relay between source and destination. Besides, the throughput can be farther improved due to its ability to cooperative retransmit by taking advantage of the spatial diversity. When there is a transmission error, the relay will retransmit the signal that it received during the error slot to the destination in the following slot. By processing the originally received error packet and the packet retransmitted by the relay, the destination node can recover the original packets. The proposed approach is approved to have good performance by simulation based on NS2 platform.