Accumulative Interference Removal in Multi-hop Linear and Circular Ad Hoc WLANs

This paper presents a cross-layered framework to study linear and circular ad hoc networks built on the IEEE 802.11e Enhanced Distributed Coordination Function. We investigate the intricate interactions among PHY, MAC and Network layers. Now, the carrier sense threshold, the transmit power, the contention window size, the retransmissions retry limit and the multi rates are jointly incorporated. We propose an equivalent network where each node is able to listen to other nodes, i.e., the effect of hidden nodes could be definitely eliminated. Then, we develop an analytical model that predicts the throughput of each connection as well as the stability of forwarding queues at intermediate nodes while each node is able to prevent the accumulative interference phenomenon. Further, performance of such a system is evaluated via simulation. We show that the performance measures of MAC layer are affected by the traffic intensity of flows to be forwarded and the average hop length. Moreover, attempt rate and collision probability are dependent on the traffic flows, PHY parameters and routing scheme.