Resource management techniques for CDMA cellular systems

The tremendous growth the cellular industry has enjoyed cannot continue without efficient management of wireless resources. Unlike wireline environments, bandwidth is a fixed resource in wireless environments. The challenge of resource management is to find ways to efficiently manage limited wireless resources to provide broadband services, making them available to the maximum number of subscribers at an acceptable level of quality of service (QoS) with the minimum cost. Code division multiple access (CDMA) is a promising technology choice for mobile cellular systems because high system capacity is possible because of its frequency reuse efficiency. The focus of this proposed research is to investigate new resource management techniques and analysis methods for CDMA cellular systems.; CDMA cellular systems will most likely employ a hierarchical architecture consisting of overlaid macrocells with underlaid microcells. Such architectures have the advantage of protecting the investment cost of existing macrocellular systems while increasing the system capacity by gradually deploying underlaid microcells. In such architectures, macrocells cover large areas with sparse traffic densities, whereas microcells serve small areas with high traffic densities. However, hierarchical system architectures pose additional resource management challenges for CDMA systems. Since both microcell and macrocell layers will share the same spectrum in CDMA systems, hierarchical CDMA systems must be able to deal with cross interference between the layers. Also, the introduction of microcells will further complicate soft handoff decisions and possibly increase the system signaling overhead.; CMDA cellular systems must be able to support wireless services with various QoS requirements. Future wireless traffic is a mixed traffic containing speech, audio, image, video, and data involving multiple participants and connections. Not only must this emerging traffic share available resources with other traffic types like conventional voice or data-only traffic, but each traffic type has different characteristics and QoS requirements. Naturally, QoS provisioning needs to be based on each traffic characteristic. An effective resource management algorithm allocates available resources to accommodate various traffic types without violating the QoS requirements of individual traffic types, while maximizing the system utilization.