Rate Adaptation MAC Protocol for High Rate IEEE 802.11 WLANs

The current IEEE 802.11 PHYs provide multiple transmission rates, but in MAC layer, the rate adaptation algorithm is not specified. This paper studies rate adaptation schemes for high rate IEEE 802.11 WLANs MAC protocol. Firstly, an Enhanced ACKnowledgement (EACK) rate adaptation protocol is presented. In EACK, the MAC header is transmitted at basic rate and the channel state information is carried by ACK frame. EACK reacts to channel variations quickly while has fewer overheads. Then, a constant transmission duration scheme with EACK (CEACK) is proposed for high rate wireless LANs which can overcome the throughput upper limit of legacy IEEE 802.11 DCF MAC and has better temporal fairness performance in hybrid rates networks.