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Call admission control (CAC) in future wireless personal communication systems is to simultaneously achieve quality-of-service satisfaction and high resource utilization. It poses significant technical challenges due to scarce radio spectrum, user mobility, hostile wireless propagation environment, end-to-end connectivity, and dynamic nature of multimedia traffic. This paper aims at providing a survey on the existing literature related to the works on CAC for future wireless systems, especially in the wireless and combined wireless/wireline domains. As the concepts of the virtual connection tree (VCT) and cell cluster have been proposed to handle user mobility, both centralized CAC policies for systems using static VCT static cell cluster and distributed CAC policies for systems using dynamic VCT dynamic cell cluster are discussed. Comparisons among the various CAC solutions are made, problems that have been dealt with and problems that need to be tackled are identified for perspective researchers in this area.

Call admission control (CAC) in multimedia wireless communications is to guarantee quality of service (QoS) to mobile users and to achieve a high resource utilization efficiency. It is a challenging issue due to user mobility, limited radio spectrum, heterogeneous nature of multimedia traffic. This paper proposes a CAC policy for a wireless system supporting both constant-rate voice calls and available-rate data calls. The parameters of the proposed policy is determined in a systematic way by using an optimization approach. Soft QoS (relaxed target QoS) is introduced to make a compromise between the QoS levels of the voice and data calls, respectively, in a heavy traffic load situation. Numerical results show that the proposed CAC policy can guarantee the QoS of all the users under most traffic conditions considered.