MAC Protocols for Multi-Channel WLANs

Wireless local area networks, in which every station can transmit via any one of the available operating channels, but only one channel at a time, are investigated. Two distributed random access protocols are proposed for these WLANs. The CSMA/CA protocol is similar to the IEEE 802.11 standard but with slight modifications for multiple operating channels. The fuzzy logic controlled protocol employs a simple fuzzy logic controller to tune the size of backoff window. Extensive simulations are provided to evaluate the channel utilization, fairness, and responsiveness of these two protocols. Furthermore, the effects of employing RTS/CTS mechanism with both protocols are considered. Finally, performances of these two protocols are also investigated under conditions of burst traffic and noisy channels. Simulation results show that the fuzzy logic controlled protocol is a great improvement of the CSMA/CA protocol. key words: wireless local area networks, MAC protocol, random access, fuzzy logic control