| dc.description.abstract | The network of the future will be a multiple heterogeneous wireless network. Because without a kind of wireless network technique and can provide high bandwidth and big service range at the same time, so through the integration of the different wireless networks, let users at any time any location all can get the suitable service. Different technique of wireless network all contains its different network characteristic, for example bandwidth. Under the different wireless network, users get different service quality. A characteristic that multicast to speak, is a kind one to multiple transmission, so if multicast can only transmit single data rate, it will not respond the different wireless network characteristic and provide the suitable serve to users.
Layered multicast is to combine a layered compression algorithm with a layered transmission scheme. A signal is encoded into a number of video encoding layers that can be incrementally combined to provide progressive refinement. So the user can aim at the different service quality demand, requesting the service quality of different video encoding layer. This thesis makes use of a need that layered multicast, purpose is on the heterogeneous wireless network environment, can satisfy different QoS requirement of different users, and combine the RSVP, letting the user be able to get suitable service quality. When the user is placed in multiple heterogeneous wireless networks, the first question would be how to reduce the services delay or interruption that handoff causes. So this thesis makes use of the concept of mobile agent, dispatching the mobile agent to request advance reservation before users handoff to another homogeneous or heterogeneous wireless network. Using mobile agent can provide the service quality assurance and reduce service time. We also proposed the policies of bandwidth reservation to overcome the services interruption caused by network congestion. The proposed bandwidth reservation policies could decrease the blocking rate of new generating calls and handoff calls.
By the simulation results, the proposed bandwidth reservation policies could decrease the blocking rate of new generated calls and handoff calls, and also decrease the packet loss rate. | en_US |