A capacity enhancing modification to RTS/CTS

Abstract

Wireless network capacity has been studied extensively in the literature. Due to its dependence on traffic profile there are many variations in how the capacity of a wireless network is defined. The traffic profile is heavily influenced by the MAC layer, and in a CSMA implementation, RTS and CTS messaging rules dictate which nodes are able to transmit to others and when. In this manner the RTS/CTS protocol directly affects the capacity of the network. This paper proposes a modification to the CTS transmission range in the RTS/CTS protocol. It is shown that selection of an appropriate range is critical, with ranges too small or too large inhibiting capacity gains. Use of an appropriate range was found to provide an average increase in network capacity of between 18%-30% depending on the network size. A multi-objective optimisation is performed to show that adjusting the transmission powers of existing nodes and appropriately placing additional nodes within the network can increase these capacity gains further and introduce substantial power savings to the network.