Throughput Properties of Fair Policies in Ring Networks

We consider a slotted ring in which simultaneoustransmissions of messages by different stations is allowed, a property referred to as spatial reuse. Ring networks with spatial reuse can achieve significantly higher throughput than standard token rings but they also introduce the possibility of starvation for some nodes on the ring. To alleviate this problem, various policies have been suggested in the literature. Our objective is to characterize the node throughputs achievable by general transmission policies in ring networks with spatial reuse and then to evaluate the throughput trade-off for a class of policies that has been proposed in the literature in order to avoid starvation. Specifically, we study a policy that is based on the idea of allocating transmission quotas to the nodes. Each node is guaranteed transmission of his quota within a specified interval. We show that by appropriately allocating the quotas, policies that satisfy general optimality criteria—in particular criteria related to fairness—can be designed. We also study the asymptotic behavior of the quota policy when either the quotas or the number of nodes increase. © 1993 IEEE