Protocol Design And Development Of Verification Platform To Support Seamless Handover In 5G Heterogeneous Networks

With the large-scale commercial deployment of the fourth generation mobile communication system (4G) based on OFDM core technology in the world, the work of 4G core technology standardization has been completed. To meet the demands of higher system bandwidth, higher data rate, higher user connection density, lower end-to-end delay and so on, the standardization of the fifth generation mobile communication system (5G)has been carried out in domestic and international organizations. The 5G network would be heterogeneous network architecture with both existed and new wireless access technologies, so the research of the switching technology among heterogeneous networks is of great significance and prospects. This papaer designs a heterogeneous convergent network architecture which is based on typical LTE and WiFi networks. However,research on related technology of switching in 5G heterogeneous networks should be implemented in the hardware platform; therefore, this paper is committed to build a test-bed based on the OpenAirInterface (OAI)software and USRP RF hardware which verifies the feasibility and performance in typical heterogeneous networks.The research of this paper mainly focuses on the following two parts: 1)the design and development of the LTE access network and the core network function module. According to the architecture of LTE and protocols of 3 GPP, we design and develop the eNB, MME, S/P-GW and HSS module under the OS of Linux. Then detailed introduce the main function of the modules and the design of heterogeneous network composed of LTE/WiFi; 2) design of seamless handover protocol of 5G heterogeneous network. This part gives a detail description of design of protocols in the core network EPC with deployment in a server as a controller to intelligently select the better network so as to ensure the smooth operations of user data in the process of handover between LTE and WiFi and meet the quality requirements. This part also describes the detailed implementation process of heterogeneous network seamless handover scenarios.The actual test results show that the platform has completed the seamless handover between LTE and WiFi as a result of package loss ratio reduced to 3.23% from about 5.59% and 4.55% compared with LTE and WiFi respectively, end-to-end delay reduced to 37.1ms from about 60.2ms toward to traditional handover. During the handover process, there does not exist frame-off or pause with a stable performance. In the next step,more implementing works of the advanced heterogeneous network technologies are needed to be verified on the test-bed to achieve a higher target.