Access priority for throughput sensitive and delay sensitive users in S-ALOHA using different backoff policies

Abstract

In this paper we propose different backoff algorithms for different classes of users. Namely, throughput sensitive users that can support higher delays but do not support a high number of retransmissions, and delay sensitive users that need to transmit their information in a time constrained base and can support a high number of retransmissions. This priority schemes are based on three of the most common backoff policies used in the random access protocols (i.e., uniform, binary exponential and geometric backoff procedures.) We analyze both throughput (by simulations) and access delay (by mathematical analysis) for S- ALOHA. We find a close form of the access delay probability distribution for uniform, binary exponential and geometric backoff policies using a Gaussian approximation. Finally, we propose a combination of these backoff policies to maximize throughput or minimize access delay according to user's type.