Study And Implementation Of UMTS Core Network Handover Technology

UMTS is the third generation mobile communication system adopting WCDMA technology. It can offer data transfer speeds of up to 2M bit/s, provide rich and colorful multimedia services such as voice, data, video, etc. UMTS subscribes can also roam smoothly all over the world. Handover technology is the key technology in UMTS, and it is absolutely necessarily in guaranteeing the subscribers moving freely in mobile communication system. Handover technology has directly influence on the quality of services supplied by UMTS.First, as a background, UMTS network architecture and work principle is introduced.Second, UMTS packet domain handover procedures are analyzed in detail. Based on 3GPP technical specifications, main exceptional procedures of UMTS packet domain intra-system handover are fully summarized and perfected. After the procedures implemented, the faults of system are decreased obviously, stability and reliability is also improved.Third, HO (handover) module in SGSN is designed and implemented. Exceptional situations are fully considered, and then stability is improved. Via SDL diagram describing and FSM designing, complex procedures are simplified and error rate is reduced, the software is clearly structured and has good maintainability.Finally, HO module is tested, including unit test, integration test and performance test, and the emphasis is put on unit test. To resolve the problems that unit test procedures in the past is not up to the standard and the test results can not be measured properly, RTRT unit test tool is used in corporation for the first time, which gives important reference to test activities in the future. The problems are resolved effectively and regression test automation is achieved. For no single-step debugging function in RTRT unit test tool, a method is put forward and the problem is resolved successfully, then capability of locating bugs in testing script is greatly enhanced.