Optimisation of RTS/CTS handshake in IEEE 802.11 wireless LANs for maximum performance

IEEE 802.11 medium access control (MAC) protocol employs two techniques for packet transmission; the basic access and the RTS/CTS reservation scheme. The latter is employed in order to improve performance as it a) shortens packet collision duration and b) addresses the hidden station problem. In this paper, we study how effective the RTS/CTS handshake is in reducing collision duration for high data rates and under ideal channel conditions by taking into account the particular packet overheads and delays defined in IEEE 802.11b wireless LANs (WLANs). Furthermore, we derive an all-purpose expression for the RTS threshold value that actually maximizes performance by employing the RTS/CTS reservation scheme whenever it is beneficial for both the packet delay and throughput performance. Results indicate that the proper selection of protocol parameters such as retry limit, initial contention window and physical packet overhead is of great importance in minimizing packet delay and improving throughput performance.