Reduction of packet delay in a WLAN with multi-round contention based CSMA MAC protocol

Abstract

The conventional single-round contention based carrier sense multiple access (CSMA) medium access control (MAC) protocols are not able to effectively utilize the opportunities of advanced physical layer techniques of multi-packet receptions in wireless local area networks (WLANs). Researchers proposed various multi-round contention based CSMA MAC protocols to increase throughput in WLANs by taking the full benefits from those advanced physical layer techniques. However, delays of the packets of a WLAN becomes high under non-saturated traffic due to the waiting time by the access point (AP) for contending multiple packets from multiple users when multi-round contention based MAC protocol is used. In this paper, a multi-round contention based CSMA MAC protocol is considered in a WLAN with successive interference cancellation (SIC) technique. An algorithm is proposed for dynamically adapting the waiting time for multi-round contentions to improve the delay performance in a WLAN under a multi-round contention based MAC protocol and SIC. The simulator of multi-round contention based CSMA protocol is modified including the proposed algorithm. Delay and throughput performances of WLANs are evaluated under non-saturated traffic via simulation with and without the proposed algorithm. The simulation results show that the proposed algorithm is very effective in reducing the packet delay in WLANs with multi-round contention based MAC protocol without degradation of throughput performance.