A Reservation-Based Multiple Access Protocol for OFDMA Networks with Adaptive Backoff Strategy

In this paper, a new wireless protocol is proposed for implementing a reservation window multiple access scheme in OFDMA networks. This scheme offers an improvement to a multichannel environment such as OFDMA by providing a controllable access scenario. A simple and practical backoff algorithm is introduced based on an adaptive backoff strategy. Each user maintains an estimate of its average traffic and adapts its backoff window size accordingly. A discrete time Markov chain analysis is applied to this protocol. Protocol performance measures such as throughput, packet acceptance probability and average energy are studied. The results obtained show that this scheme is a very effective multiple access protocol for point-to-multipoint (PMP) OFDMA applications such as IEEE 802.16d networks.