Radio resource management in broadband wireless access networks

Broadband wireless access (BWA) technology such as IEEE 802.16-based WiMAX (Worldwide Interoperability for Microwave Access) systems, IEEE 802.11-based wireless local area networks (WLANs), i.e., WiFi networks, and beyond 3G cellular systems are being developed to provide high speed wireless connectivity and seamless mobility to users. Integration of these different technologies will give rise to a heterogeneous wireless access environment. Although the WiMAX standard defines the signaling messages for medium access control (MAC) mechanisms, radio resource management protocols for dynamic bandwidth allocation, subcarrier allocation, connection admission control and many other aspects are left open for innovations. Also, issues related to an integration of WiMAX networks with 3G and WiFi systems need to be resolved. Efficient protocol engineering, which is the theme of the research results presented in this report, would be critical for cost-effective deployment and operation of BWA technologies. In this research, resource management protocols are designed and optimized for WiMAX broadband networks and integrated WiMAX-WiFi networks.;The problem of radio resource management for WiMAX networks is considered at both subscriber stations (SS) and base stations (BS). Specifically, queue-aware bandwidth allocation and rate control mechanisms are proposed for WiMAX subscriber stations. While bandwidth allocation is used to allocate radio resource at the SS, rate control is used to limit the transmission rate of the traffic source to maintain the target quality of service (QoS) performance. A queueing analytical model is proposed to investigate the performance of these bandwidth allocation and rate control mechanisms. Afterwards, the resource management problem at the WiMAX base station is addressed. A queueing mode is formulated to obtain the QoS performance measures which are used by the bandwidth allocation algorithm at the WiMAX BS to allocate available bandwidth among the different connections. Two bandwidth allocation algorithms, namely, the optimal and the iterative algorithms, are proposed. While the optimal algorithm provides the best solution of resource allocation, the iterative algorithm incurs much less computational overhead.;A radio resource allocation framework is proposed for an integrated WiMAX-WiFi network where the WiMAX network serves as a multihop backhaul network for relaying Internet traffic to/from WiFi networks. For such a network, the problem of bandwidth allocation among local and relay traffic at a WiMAX base station (i.e., mesh router) is considered. Then, the resource allocation problem in an integrated WiMAX-cellular-WiFi network is considered where a mobile user is able to connect to the different access networks simultaneously. For such a network, the resource management problem is solved considering a cooperative environment where all available networks offer bandwidth to users to satisfy their QoS requirements. Then, this problem is solved considering a noncooperative environment where all networks are operated by different rational service providers.