Improving the performance of WLAN to support VoIP application

VoIP over WLAN (VoWLAN) has become increasingly popular. But some limitations of IEEE 802.11 point coordination function (PCF) make IEEE 802.11 WLAN not meet the requirements of real-time traffic such as VoIP. In this paper, we analyze the polling scheme and its limitation of the PCF of IEEE 802.11 WLAN. Based on that, we propose an improved deficit round robin (DRR) polling scheduling algorithm, which can enhance the performance of WLAN to support voice application. Compared with the basic PCF polling scheme, the proposed polling algorithm provides more efficiency for the access point (AP) to poll the VoIP stations (STAs). Performance evaluations of the algorithm are presented and the simulation results show that the proposed algorithm can improve the quality of service (QoS) of VoIP applications over WLAN by providing lower access delay and higher throughput, especially when the number of STAs increased rapidly