Strategy Of Handover And Resource Allocation In Integrated Satellite And Terrestrial Networks

As the increasing demands on new kinds of services, wide bandwidth and ubiquitous connection support, heterogeneous networks converging is being considered as the trend of next generation communication system. In the meantime, the satellite networks, as a vital complementation to terrestrial wireless networks, is also becoming an important direction for the future networks. As a result, the next generation communication system becomes a heterogeneous system including satellite and terrestrial networks. A critical problem in the in integrated satellite and terrestrial networks is radio resource management. Especially, the research on the strategy of handover and resource allocation has greatly interested of both academe and industry.This thesis focuses on the strategy of handover and resource allocation in the integrated satellite and terrestrial networks, mainly including:vertical handover management scheme, QoS mapping mechanism and strategy of joint resource allocation.In terms of vertical handover management scheme, a mobility management architecture of GEO satellite based on 3G WCDMA R4 is proposed in this thesis. The functional entities are mainly inherited from R4, in which the interfaces and corresponding protocols are modified and complemented for the satellite networks. This thesis designs the handover procedure between the satellite network(R4) and the terrestrial networks, including WCDMA and GSM. The handover procedure consists of CS domain and PS domain.With respect to QoS mapping mechanism, a novel asymmetric QoS mapping scheme in the handover between terrestrial and satellite networks is proposed in this thesis. This mechanism makes users in the terrestrial network degrade their requirements to access the satellite network with lower QoS class than they have in the terrestrial network when traditional one-one mapping fails. The users can recover their previous QoS class once the satellite network capability becomes available again. This scheme reduces handover blocking probability and improves the resource utilization. It is implemented in vertical handover procedure based on IEEE 802.21.For the resource allocation in integrated satellite and terrestrial networks, based on the investigation of resource allocation algorithm in MU-OFDM network and DVB-S2/RCS system, a new strategy of joint resource allocation proposed in this thesis. A mathematical model of the joint resource allocation is established in which the utility and fairness are both considered. Based on the theoretical analysis of optimal solutions by convex optimization, a method of network selection and an algorithm of resource allocation are proposed. Simulation results show that the performance of proposed strategy is closest to the optimal solution compared with other schemes.Finally a summarization is made and the future direction of the study is pointed out.