Research And Design Of SI Handover Technology In LTE System

LTE is the Long Term Evolution of UMTS, it improves and enhances the radio accesstechnology of the3G. LTE based on OFDMA、SC-FDMA、MIMO. The Target of LTEsystem include improve the performance of users in the edge of cell and reduce systemlatency and so on.Realization of this goal requires support of handover, which from the source cell totarget cell. Handover in LTE system include S1handover、X2handover and handover intraeNodeB. In order to realize S1handover, this paper based on analysis S1AP、X2AP、RRCprotocol and make a depth research on S1handover process. Analyzing and comparingcurrent process of S1handover、X2handover and handover intra eNodeB. We design thenormal S1handover process and abnormal handling process separately. For normal process,we proposed a S1handover method from the perspective of signaling among callingcontrol module and other modules. With the coordinative of modules in EPC and eNodeB,ensuring UE could handover from the source eNodeB to target eNodeB and no packet lossin the process. For abnormal process, we also proposed a handover exception handlingalgorithm, adopting different ways according to different stage and cause of abnormity.Ensuring handling properly when encountered exception during handover process and UEaccess the appropriate cell, thereby improving the process of S1handover.We can partition the article into three segment: the network architecture、 functiondividing and interface description of LTE system、the research of S1handover process andthe implement of S1handover and the analysis the test result. Firstly, we introduce the basenetwork element in LTE system, the function of network elements and interface amongthem. Then we make a detail analysis about handover process in LTE system, includinghandover measurement process、handover decision process、handover execution process.We mainly analysis several signaling procedure related to handover. Finally, we make adetail design about entire S1handover process, including design in eNodeB side and EPCside, and then verifying normal handover process in network test, laying the foundation for future study on S1handover.