MAC protocol using cooperative active relays in multi-rate wireless LANs

In wireless local area networks (WLANs) based on IEEE 802.11 families such as a/b/g, mobile stations can automatically adjust transmission rates according to channel conditions. However throughput performance degradation is observed by low-rate stations in multi-rate circumstances resulting in so called performance anomaly. There have been many studies to solve this type of degradation and recent researches introduce efficient techniques using cooperative communications to enhance throughput. In this paper, we propose active relay-based cooperative medium access control protocol (AR-CMAC). ARCMAC protocol uses active relays desiring to transmit their own data for cooperation in contrast to other existing MAC protocols and is designed to increase throughput. Simulations in an infrastructure network with an AP show drastic improvement approximately 2 times than the legacy IEEE 802.11b with RTS/CTS in terms of throughput.