The Research On Optimization Strategy Of Resource Allocation For Unicast And Multicast Mixed Wireless Systems

In recent years, with the development of technology in wireless mobile communications and the appearance of portable user equipments, mobile multimedia services have been paid more and more attention, such as mobile TV and VOD services. The related standardization organizations also have taken on their works with the research about broadcast and multicast to provide the mobile multimedia services in the cell mobile networks with high efficiency of resource. Some standards have been published, eg. MBMS of 3GPP, BCMCS of 3GPP2 and MBS of mobile WiMAX system forum, etc..Wireless unicast and multicast are two distinct transmission schemes with respective advantages. The unicast transmission scheme can exploit multiuser diversity. Multicast transmission scheme can get multiuser gain, in the case which the transmission rate of the multicast group should be adjusted according to the user with the worst channel. The cellular mobile communications systems will support the two transmission schemes in near future, so how to cope with the problem of resource allocation becomes an important research issue.Two schemes focused on unicast and multicast mixed wireless systems are presented in this thesis. The first one is an optimization transmission scheme based on cross-layer information (Cross-Layer Optimization Transmission Scheme) for multiple multicast groups and unicast traffic mixed scenario, which combines the user request information for services and the user SNR distribution information together. The proposed scheme is compared with the traditional one in terms of the average rate and capacity of multicast through theoretical analysis and simulation results. Additionally, for the scenario of mixed mobile TV and VOD services sharing system resource, this paper proposes to provide mobile TV service with mixed multicast and unicast transmission schemes, the related system model is studied, and the effects of different parameters on the optimized multicased number for mobile TV channels and the performance of service blocking probability are shown. The theoretical analysis and simulation results demonstrate that the proposed scheme can enhance the system performance when the total system resource is fixed. At last, all the research work done in this thesis is concluded and the prospective study in future is given.