Performance evaluation of PRMA with priorities for wireless ATM

A backoff scheme for multiclass users is described and simulated. It combines the original packet reservation multiple access (PRMA) protocol with two new features: different classes of users, and different priorities and retransmission probabilities for those classes. Users who collide when trying to reserve the channel are distributed in subsets according to their class. Subsets are created using a splitting algorithm, and a different permission probability is assigned to each of them. Three sets of parameters have been measured in the mentioned system: average access delay, blocking probability and percentage of packets blocked for establishing the call. A comparison with the original PRMA is made.