Cooperative Rate Adaption Scheme for Wireless Networks with Improved Fairness, Delay and Transmission Reliability

摘要

We propose a Cooperative Rate Adaptation (CRA) MAC protocol based on the standard CSMA/CA protocol used in IEEE 802.11 wireless networks. The proposal provides cooperative error recovery, namely cooperative packet retransmission, while using rate adaptation. The transmission rate is selected based on the transmission rate history of the neighbours. The cooperating partner is selected based on a fuzzy logic selection algorithm. Three inputs are considered in the fuzzy system: the average transmission rate of a neighbour, the erroneous packet ratio and the acknowledged packet ratio of a neighbour. The output of the fuzzy system is the partnership probability of a neighbour. In this paper, the protocol is compared to the non-cooperative rate adaptation scheme RBAR (Receiver Based Auto Rate) and to the cooperative rate adaptation scheme CRBAR (Cooperative Relay Based Auto Rate). The simulation results show that the proposed protocol improves the delay and packet delivery ratio while contributing to the transmission opportunity fairness among the terminals, regardless of their channel conditions.