Group Random-Access Disciplines for Multi-Access Broadcast Channels.

摘要

A Group Random-Access (GRA) access-control discipline for a multi-access communication channel is presented and studied. A GRA Scheme uses only certain channel time-periods to allow some network terminals to transmit their information-bearing packets on a random-access basis. The channel can thus be utilized at other times to grant access to other terminals, or other message types, by applying, as appropriate, group random-access, reservation or fixed access-control procedures. GRA schemes could also be utilized to provide channel access to various network protocol packets. The average packet delay under a GRA discipline is evaluated by a Markov ratio limit theorem. To stabilize the channel, the GRA procedure is controlled dynamically by a control policy which rejects any newly arriving packets within certain time-periods. Studying the associated Markov decision problem, the optimal control policy is characterized as yielding a minimal average packet delay under a prescribed packet probability of rejection. This policy is shown to be a single-threshold scheme for which there exists a threshold value which attains the minimum probability of rejection. Performance curves are presented to demonstrate the excellent delay-throughput characteristics induced by GRA procedures. (Author)