Abstract
Radio resource is scarce in wireless networks. From the perspective of the wireless system, it is desirable to make efficient use of the radio resource. From the viewpoint of mobile users, it is required that quality of service (QoS) provided by the system should be as high as possible. It is essential to develop resource management schemes for wireless networks such that the utilization of radio resource is efficient while good QoS is provided for mobile users. In this dissertation, we address technical issues on radio resource allocation and QoS provision in micro/picocellular wireless networks. First of all, we focus on cluster-based micro/picocellular wireless networks, in which the collection of cells covered by the base stations under the control of a switch is called a cluster. We propose a call admission control policy that employs two levels of admission thresholds: one at the cell level and the other at the cluster level. An analytical method is developed to analyze the performance of the proposed policy. Compared with call admission policies that employ a single threshold either at the cell level or at the cluster level under the condition that the policies provide the same predetermined maximum level of call hand-off dropping probability, the proposed call admission policy provides significantly higher throughput. The concept of overlap clusters has been suggested in previous literature to prevent frequent cluster hand-offs that occur when mobile users move back and forth between the clusters. However, cluster channel assignment in overlap clusters and hand-off policies in overlap areas have never been studied before. We propose two cluster channel assignment policies, and two hand-off policies. The proposed cluster channel assignment policies and hand-off policies are combined to obtain three different strategies, namely, partitioned-boundary, partitioned-early, and shared-boundary strategies. Simulation results show that the partitioned-early and shared-boundary strategies produce significantly lower hand-off dropping probability than the partitioned-boundary strategy. Besides studying overlap areas between clusters, we also study overlap areas between cells. It is unavoidable that overlap areas exist between adjacent cells in order for mobile users to gain services from anywhere in the service areas of cellular wireless networks. We study two techniques in the environment that neighbor cells overlap with each other. One is channel rearrangement technique that enables a mobile user in the overlap area to handoff to another cell, such that the released channel(s) can be used by a new user or a handoff user. The other is bandwidth adaptation that selects a subset of mobile users and adjusts the bandwidth allocated to the mobile users in order to achieve certain goal. We propose optimal channel rearrangement and optimal bandwidth adaptation schemes for multiclass traffic in cellular wireless networks. The optimal channel rearrangement and the optimal bandwidth adaptation schemes significantly improve QoS and carry more traffic. Finally, we address radio resource management in a cell. We consider existing TDD based packet reservation multiple access (PRMA) protocol and its variations, which enable mobile terminals to transmit and receive packets to and from a centralized base station on a shared radio medium. Two PRMA based schemes are proposed in this dissertation. One is slanted frame arrangement scheme that enables a mobile terminal to switch among different frequency carriers such that shorter time is required to obtain a slot at the beginning of a talk spurt or a burst of data. The other is dynamic non-collision PRMA (DNC-PRMA) that dynamically allocate control mini-slots to mobile terminals such that the channel throughput is increased dramatically. Simulation results show that the slanted frame arrangement scheme and the DNC-PRMA significantly improve performance.