| The next generation wireless system (NGWS) is a system of globally available, wireless multimedia networks that are anticipated to deliver service to a mobile computer terminal “anywhere at anytime.” Whereas conventional handoff techniques support single connection terminals that operate within a homogeneous network, NG wireless systems promise to support terminals with multiple connections carrying different types of traffic, with varying quality of service (QoS) constraints, which may handoff between different tiers of the same network, or between different types of networks. In this thesis, new handoff techniques were developed to support global roaming with QoS constraints within NG wireless systems. For intra-system roaming, a new handoff technique for real-time traffic in Mobile IP version 6 networks was created to adapt to IP-based QoS architectures. Disruption of the communication path, bandwidth expenses, and buffering requirements were reduced. Next, a new handoff technique was developed for Wireless ATM networks that used the source switch to manage connections with multiple mobile endpoints, and to reroute connections according to the type of traffic being carried. For inter-system roaming, new boundary elements were introduced to the NGWS architecture. A new inter-system handoff signaling and rerouting protocol was created to enable format transformations and advanced preparation for mobile terminals that may roam between a variety of networks. Finally, an admission control algorithm for inter-system roaming was created to provide a mechanism for QoS re-negotiation and to regulate the admission non-subscriber traffic. |
