Investigation On Call Admission Control In TD-SCDMA System

Recently, As a important part of radio resource management (RRM) and a important method for providing the QoS of user in mobile communication,call admission controll(CAC) gets more attention. With the increasing requirement of users' demand, the wireless communication of network will afford several traffic of different type transmission rate and the service of quality(QoS) requirement in the future. So how to efficiently manage and use the wireless resource is one of the most important problems for the service providers.Compared that FDD mode is used in the system of WCDMA and CDMA2000, TDD mode is adopted in TD-SCDMA system, and time slot resources is also added in the the system,which is very convenient for the technology of Multi-User Detection (MUD). As MUD is used in TD-SCDMA system ,the interference in TDD system is very different from the FDD system. And the research results of some exiting CAC policies previously are always based on that the factor of MUD is constant,but the technology of MUD is just support in local district,it can not deal with the interference near the local district. so under the complex traffic model,imperfect power control and asymmetric traffic,we necessary analyse the affect to QoS which factor of MUD is changed according to the arriving rate in TD-SCDMA cellular system.In this thesis,the research result previously is fully generalized, call admission control policies in wireless multimedia communication networks of TD-SCDMA are proposed based on QoS requirements.First, according to the characterist of wireless communication network in the future, a residual capacity based call admission control policy is proposed,and the factor of MUD is also calculated in the system, So in this thesis, a new CAC policy with dynamic QoS guarantee for TD-SCDMA system is proposed. The basic idea of this method is that: the operators define the priority and QoS according to their requirements. Call admission control is executed according to the residual capacity and the priority and QoS of traffic.Secondly,base on the CAC policy,the affect to the QoS of TD-SCDMA system which arise in different factor of MUD and interference factor of nearly district according to different arriving rate is analysised in this thesis. The simulation results show that this policy can guarantee the QoS for different traffic efficiently,and it can improve the performance of QoS and utilization of system resource. Finally,the thesis is fully generalized.