NAV (Network Allocation Vector)-Based Differentiation Mechanism for VoWLAN Enhancement

Voice over Internet protocol (VoIP) over a wireless local area network (WLAN) is becoming an important application. However, the performance of voice over WLAN (VoWLAN) is compromised severely in the presence of heavy coexisting traffic from other applications even if the IEEE 802.1 le MAC protocol is utilized. This problem poses a severe challenge to the harmonious coexistence of VoIP and other application in WLAN. This paper proposes and investigates a scheme that modifies network allocation vector (NAV) update process of voice terminals. The extensive simulation in the paper demonstrates that the voice capacity of WLAN with coexisting applications of voice service and best effort service can be largely improved by the proposed simple solution compared with EDCA protocol. Specifically, in our proposed method, only the MAC protocol at the voice stations (STAs) should be modified, which makes the proposed solution more readily deployable over the existing network infrastructure.