Impact of overlapped transmission on the performance of TCP in multihop ad hoc networks

Abstract

Multihop routing in wireless ad hoc networks creates situations in which some nodes know the content of packets being transmitted by neighboring nodes. This knowledge enables simplified interference cancellation schemes that can be used to schedule additional transmissions in the network. This approach, which we call overlapped transmission, can significantly improve the performance of ad hoc networks in a variety of scenarios. Recently, we proposed the Overlapped Carrier Sense Multiple Access (OCSMA) protocol to coordinate overlapped transmissions and increase the spatial reuse and throughput of wireless ad hoc networks. In this paper, we investigate the interactions between TCP and OCSMA in wireless ad hoc networks. We analyze the impact of overlapped transmission on the performance of TCP flows in a variety of network scenarios. Through network simulations, we demonstrate the superiority of OCSMA over conventional medium access control (MAC) protocols in addressing the fairness and medium contention issues of TCP in multihop wireless networks.