Throughput-delay characteristics of OCUM protocol for media access in multihop wireless networks with buffers

In this paper, we present the throughput and delay performance of a busy tone based media access protocol in wireless networks with buffers at each node for queueing up messages. Partially connected static topologies with finite number of nodes that are globally synchronised to the slot duration are considered. Each node has unlimited buffer resources for transit messages and limited buffer capcaity for newly arriving entry messages. The input buffer limiting policy rejects new message arrivals when the total number of queued up messages (including entry and transit messages) exceeds a finite buffer threshold ’L’ at each node. Messages are serviced on a First Come First Served basis. Simulation results for fully connected, ring, bus, multiconnected ring, square lattice and other arbitarary topologies are presented. The protocol offers constant throughput of the order 0f 0.8 0.9 at high arrival rates in a fully connected network. Throughput is found to improve at low arrival rates as the value of L s increased. However, the improvement becomes marginal for L > 4. For other multihop topologies like ring, bus, multiconnected ring and square lattice the throughput performance improves beyond unity due to spatial reuse.