Maximum throughput analysis for RTS/CTS-used IEEE 802.11 DCF in wireless multi-hop networks

The purpose of this paper is to analyze the maximum throughput when using RTS/CTS (Request To Send/Clear To Send) in IEEE 802.11 Distributed Coordination Function (DCF) multi-hop networks with a novel approach. Wireless multi-hop networks, in which nodes communicate with each other and convey packets via intermediate nodes without centralized control, have gained increasing attention because of the extension of the wireless communication range associated with such networks. In wireless multi-hop networks, the IEEE 802.11 DCF based on the Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) has been commonly used as a Medium Access Control (MAC) protocol. IEEE 802.11 DCF is specifically designed for single-hop wireless LANs, which makes quantitative analyses of the contention behaviors occurring at nodes in typical network topologies important. Although several quantitative throughput analyses for wireless multi-hop networks have been reported, few analyses have examined the use of RTS/CTS in IEEE 802.11 DCF multi-hop networks. While RTS/CTS is effective for avoiding packet collisions caused by hidden terminals, an overhead problem occurs due to the increase in the number of RTS/CTS control packets. As the number of RTS/CTS control packets increases, the collisions between RTS/CTS control packets occur more frequently. The analysis of networks that use RTS/CTS has been considered difficult because of the complex behaviors of RTS/CTS. The present paper introduces a novel approach to the analysis of throughput for networks that use RTS/CTS by considering one-way flow in string multi-hop networks. The end-to-end network maximum throughput is obtained by analyzing the maximum throughput of bottleneck nodes. This analysis provides the transmission failure probability considering not only RTS-RTS collisions but also the influence of the Network Allocation Vector (NAV). A simulation is carried out, and a comparison of the analytical and simulated results validat- - es the proposed analytical expressions.