| It is clear that the new generation of wireless network architecture is IP based packet network, where the high grade high QoS services (such as the real time vedio service) are normally expected. Because of the mobility nature of the mobile equipment, the path of service data stream is changed frequently. Therefore, it makes a great challenge to support a high QoS service for mobile users, which is the main research area of this thesis.Now many QoS guarantee mechanisms have used the strategy of advanceresource reservation. Basically, These mechanisms can guarantee the QoS of the mobile equipment in wireless access network, but at the expense of too much bandwidth for reserving resources. This thesis aims at finding a more efficient QoS guarantee mechanism.In this thesis, firstly the techniques related to QoS are analyzed. Two IP QoS models generally adopted by wireless access network are Intserv Model and Diffserv Model, which are discussed in details. Then the thesis discusses the existing problems and the possible reasons of the two models for wireless network applications. Based on the analysis and comparison of some existing schemes, a new improved scheme of Intserv Model is proposed.The new scheme uses the hierarchical mobility management mechanism, i.e. FCAR mechanism, to realize mobility management in wireless access network. Based on the RSVP protocol signaling, new signaling is introduced to reserve the passive resource on the path between the SA and the neighbor cell's station of mobile equipment, in order to guarantee that a mobile equipment can get the network resource as soon as the handoff is finished. Finally, the modeling and simulation of the new scheme are carried out. The simulation results show that the new scheme can ensure the data streams of wireless access network to obtain high QoS grade with less reserved bandwidth and less signaling overheads. |
