Enhancement of VoIP over IEEE 802.11 WLAN via dual queue strategy

Today's IEEE 802.11 Wireless LAN (WLAN) is an excellent solution for the broadband wireless networking. However, it lacks of the capability to support real-time services such as Voice-over-IP (VoIP) properly. In this paper, we present a simple and viable approach to enhance the VoIP performance over the 802.11 WLAN by implementing two queues along with a strict priority queuing on top of the 802.11 Medium Access Control (MAC) controller, e.g., in the device driver of the 802.11 cards. We find via extensive simulations that the proposed scheme is remarkably effective for the VoIP service in the infrastructure-based WLAN in the coexistence with the non-real-time traffic thanks to the flow control mechanism of the TCP protocol, which is typically used for the non-real-time traffic today. Due to its simplicity, the proposed scheme should be readily deployable in the existing WLANs via simple software upgrades for the enhanced VoIP services.