A Pseudo-Bayesian ALOHA Algorithm with Mixed Priorities

In reservation-based multiple access protocols, before obtaining a contention-free access to the channel, a mobile terminal must wait for its request packet to be successfully sent to the base station. A pseudo-Bayesian ALOHA algorithm with multiple priorities is proposed in this paper to reduce the waiting time of delay sensitive request packets in a multimedia environment. Packets are transmitted in each slot according to a transmission probability based on the channel history and a priority parameter assigned to their respective priority class. An adaptation of the slotted protocol to the framed environment proposed for wireless ATM is also described. Simulation results are presented to show that the protocol offers a significant delay improvement for high priority packets with both Poisson and self-similar traffic while low priority packets only experience a slight performance degradation.