A novel QoS-aware MAC protocol for voice services over IEEE 802.11-based WLANs
With the pervasive growth in the popularity of IEEE 802.11-based wireless local area networks (WLANs) worldwide, the demand to Support delay-sensitive services Such as voice has increased very rapidly. This paper provides a comprehensive survey on the Medium access control (MAC) architectures and quality of set-vice (QoS) provisioning issues for WLANs. The major challenges in providing QoS to voice services through WLAN MAC protocols are outlined and the solution approaches proposed in the literature are reviewed. To this end, a novel QoS-aware wireless MAC protocol, called hybrid contention-free access (H-CFA) protocol and a call admission control technique, called traffic stream admission control (TS-AC) algorithm, are presented. The H-CFA protocol is based on a novel idea that combines two contention-free wireless medium access approaches, that is, round-robin polling and time-division Multiple access (TDMA)-like time slot assignment, and it increases the capacity of WLANs through efficient silence Suppression. The TS-AC algorithm ensures efficient admission control for consistent delay-bound guarantees and further maximizes the capacity through exploiting the voice characteristic that it can tolerate some level of inconsecutive packet loss. The benefits of the proposed schemes are demonstrated in the Simulations results. Copyright (C) 2008 John Wiley & Sons, Ltd.
call admission control wlan capacity real-time qos mac scheduling