Due to terminal mobility and change of service area, efficient IP mobility support is animportant aspect in UMTS networks in order to provide mobile users negligible packetloss rate and low handover latency, and thus some level of guaranteed quality-ofservice(QoS) to support real-time applications. 3G/UMTS has been specified andimplemented as an end-to-end mobile communications system. The underlyingWCDMA access systems manage radio access handover (layer 1) and provide linklayermobility (layer 2) in terms of connection setup and resource management. Forthe UMTS nodes to have seamless connectivity with the Internet, the UMTS corenetworks need to be able to support continuous and no network service sessionhandover (layer 3 and above). A long IP handover latency results in high packet lossrate and severely degrades its end-to-end transport level performance. Network-layerhandover latency has therefore been regarded as one of the fundamental limitations inIP-based UMTS networks. Therefore, it is crucial to provide efficient network-layermobility management in UMTS/WCDMA networks for seamless end-to-end TCPconnection with the global Internet.Mobility of UMTS nodes necessitates extra functionalities such as user locationtracking, address registration and handover related mechanisms. The challenge toprovide seamless mobility in UMTS requires localised location management andefficient IP handover management. Mobile IPv6 protocol offers a better mobilitysupport as the extended IPv6 features with mobility mechanism are integrated to themobile nodes. To mitigate the effect of lengthy IP handover latency, two well-knownhandover reducing mechanisms based on Mobile IPv6 support have been proposed inthe literature. They are designed with hierarchical network management and addresspre-configuration mechanism. Hierarchical management aims to reduce the networkregistration time, and fast-handover attempts to minimise the address resolution delay.S-MIP (Seamless Mobile IP) integrates the key benefits of the above IP mobilitymechanisms coupled with local retransmission scheme to achieve packet lossless andextremely low handover latency, operating in WLAN environments.In this thesis, we explore the possible Mobile IP solutions and various IP handoveroptimisation schemes in IPv6 to provide seamless mobility in UMTS with the globalInternet. It aims at developing an optimised handover scheme that encompasses thepacket lossless and extremely low handover latency scheme in S-MIP, and applying itinto the UMTS/WCDMA packet data domain. Therefore, the hybrid UMTS-SMIParchitecture is able to meet the requirements of delay sensitive real-time applicationsrequiring strict delay bound, packet lossless and low handover latency performance forend-to-end TCP connection during a UMTS IP-based handover. The overall seamlesshandover architecture in UMTS facilitates integrated, scalable and flexible global IPhandover solution enabling new services, assuring service quality and meeting theusers expectations in future all-IP UMTS deployment.The viability of the seamless mobility scheme in UMTS is reflected through andvalidated in our design model, network protocol implementation, and servicearchitecture. We illustrate the performance gained in QoS parameters, as a result ofconverged UMTS-SMIP framework compared to other Mobile IPv6 variants. Thesimulation results show such a viable and promising seamless handover scheme inUMTS on IP handover latency reduction on its end-to-end TCP connection.
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