Demand assigned multiple access systems using collision type request channels: Priority messages

Demand Assigned Multiple Access (DAMA) schemes in which requests for communication channels are transmitted over collision type channels to a master controller and in which messages of different priorities are present is analyzed. Priority use of the request channels is achieved by having users select among those channels according to a priority dependent probability distribution. Two important schemes of this class are considered. Additionally, three schemes for priority assignment of message channels are treated; two are non-preemptive and one is preemptive. Trade offs among bandwidth utilization and delay are considered as well as optimization of system parameters.