Performance evaluation of a new fairness control scheme for ring networks with spatial reuse

We consider a ring in which simultaneous transmission of messages by different stations is allowed, a property referred to as spatial reuse. A ring network with spatial reuse can achieve a network level throughput much higher than the channel rate. A widely used scheme to achieve spatial reuse is Buffer Insertion Ring (BIR). However, because non-preemptive priority is given to the ring traffic, BIR scheme can lead to fairness problems in distributing the ring bandwidth among distinct nodes. In this paper, we propose a novel approach that provides fair access to all nodes and features low complexity. Within each node, the proposed approach allocates a separate queue for every upstream node. Each queue receives its fair share of the ring bandwidth based on an assigned weight value. Performance of the proposed scheme in terms of fairness and average packet delay has been evaluated through both simulations and analysis. The results show that the new scheme called Source-Based Queuing (SBQ) can provide fairness with less end-to-end delay compare to the BIR scheme.