Research And Analysis On The Abnormal Problem Of CSFB Voice Solution In LTE

The future evolution of mobile communication system has been locked into LTE network at this stage. The network has been attracted broad attention from China Mobile, China Unicom, China Telecom, HUAWEI, ZTE, Ericsson and other operators and many domestic and foreign manufacturers of equipment. It uses a unified packet structure and no longer have to support the voice of original circuit domain. On the basis of the traditional voice solutions develop three new voice solutions in 4G network including two modes UE, CSFB and VoLTE. However, in order to make the network access terminal can be normal use speech function in the initial stage of the LTE network, and also don’t waste the existing 2G, 3G network resources at same time, so according to the relevant requirements of the 3GPP23.272 must use CSFB technology to solve the problem of speech in LTE network.I am mainly responsible for the data analysis in the CSFB network deployment project. The CSFB’s main abnormal problems include CSFB call establishing exception, abnormal problems of CSFB return to LTE and CSFB call setup delay. As the CSFB exception is a new topic, there is no ready-made solution to the project. Therefore, the main work of this paper is to study the problem of CSFB and give a comprehensive solution on it.This topic mainly expansion research and analysis according to the principle of the CSFB technology. First, main functions of its structure and element in LTE network were introduced briefly. Second, this paper focuses on the realization CSFB principle, key technologies and CS fallback signaling flow. Third, the abnormal issue makes a classification according to the abnormal problems which occurred in the actual CSFB network. The abnormal issues are terminal setting problem, wireless parameter setting problem, core network parameter setting problem, network construction problem and wireless network coverage problem. At the same time, the solutions to these problems are put forward. Through analyzing of the case, the "three methods" of the CSFB anomaly which is 4G paging analysis, 4G release analysis and 2G access analysis is summarized. Through the summary of the analysis method and the abnormal issue solutions, it plays a guiding role in the follow-up of the CSFB anomaly research.