A unified approach to analyze multiple access protocols for buffered finite users

Multiple Access Control (MAC) protocols play a vital role in determining the performance of wireless local area networks (WLANs). With developments at the physical layer, new MAC protocols are required to make efficient use of the bandwidth available. Newly conceived applications for these technologies, and the ever-increasing demands that they place on the MAC protocols, also requires constant effort in this area. These factors ensure that MAC protocol development is currently relevant and will continue to be well into the future. As such, it is important that design methodologies for these systems are well understood. MAC protocols have unique requirements due to their position in the network stack. By definition they must interact closely with the physical layer, meaning strict observance of oftentight timing requirements. A conflicting demand is brought by increased pressure for low-level functionality to support facilities such as Quality of Service (QoS) and security. While a variety of MAC protocols have been proposed recently for wireless LANs, the problem of efficient bandwidth utilization, higher throughput, lower mean delay, and fairness has not been fully solved yet. For example, IEEE 802.11 protocol does not perform well and the bandwidth utilization drops below 50% of the total bandwidth under heavy traffic load conditions. In the study of various performance parameters for IEEE 802.11 networks, it has never been a case, where any single performance metric has been used by the WLANs to indicate the QoS to the user. Moreover, the WLANs itself does not provide guaranteed end-to-end Quality of Service. Thus, the study revealed that there was a need to develop a unified performance model which takes care of inter-dependence amongst various network performance factors for IEEE 802.11 networks while assessing the QoS in the WLAN setups. Further, the top five layers on the OSI protocol stack being a constant factor for all types of wire line or wireless networks, the MAC layer is the single most important layer which should be considered for evaluating performance of Wi-Fi networks. The MAC layer also being a common denominator between all IEEE 802.11 protocol families makes it even more relevant for performance issues. The Universal Access Method (UAM) is a recommended methodology proposed by Wireless Internet Service Provide roaming (WISPr) A Wi-Fi alliance committee for providing secure web-based service presentment, authentication, authorization and accounting for roaming users in Wi-Fi networks. In order to facilitate with the widest range of legacy Wi-Fi products, the committee recommended that WISPs or hotspot operators adopt a browser-based Universal