Handover Technology In 3G Netwroks

Mobile system's development went through profound change in the past tens of years, and the hottest topic today is 3G. UMTS is the next generation of GSM standardized by 3GPP, and the network architecture is toward all IP core networks. It can decrease the overhead of roaming and interworking among operators, and benefit the users ultimately.The thesis discusses the Handover/Relocation subsystem of 3G_MSC server in UMTS core network CS domain, and further does some research on the integration with IP networks. First, the Mobile system development and current situation of Chinese marchet are described, with a brief background of the project and the architecture of the whole thesis; then, the network architecture of the UMTS and the preliminary design of 3G_MSC server software system, including module definition, scheduling machine realization and system data definition; on basis of the above, the preliminary and detailed designing of the Handover/Relocation module, the handover types, the procedures and implemantation of the Handover/Relocation sub-system.The thesis propose these designing ideas: Independent Handover/Relocation module designing; bearer termination management; ASN.1 encode/decode; configuration information decision; Handover number Index table; buffer message in simutanious events; Iu-agent function after successful inter-3G_MSC Handover/Relocation procedure (Basic/Subsequent); No standby stratigy for Handover module; No waiting stratigy after Handover/Relocation failure in the core networks; Inormal conditions release stratigy and some software realization things. The describe the engineering implementation of Handover/Relocation module, including the test stubs of Ranap-gate, Isup-gate, B-gate, Map-gate, MGC. The results show that the designing of the Handover/Relocation module is reasonable and pratical. The thesis further dicusses the handoff technologies in packet-switched networks – Macro-mobility and Micro-mobility solutions, and give a further vision of the handoff technologies of the all IP core networks in the near future.