Optimal Retransmission Control of Slotted ALOHA Systems

Multiple access methods constitute an important subject in the design of distributed computer communication systems. A technique which has attracted considerable attention is the slotted ALOHA random access scheme. In this paper, based on some analytical properties of the slotted ALOHA system [9], we establish the optimality property of the multiple control limit policy among the class of multiple-action policies. The previously reported control limit policy [6] is just a special case. We then derive the optimal retransmission control (ORC) policy which is optimal among the whole class of stationary policies. The superiority of the ORC policy is also illustrated by numerical examples. The performance of the ORC policy for various potential input traffic intensity is presented.