Analysis And Implementation Of NAS Protocol Of Air Interface In LTE-A Network Monitoring Instrument

With the rapid commercial application of the 4G and the number of subscriber's explosive growth,the new network brings users a more favorable network environment and business experience, at the same time, higher requirements for network maintenance and optimization have been put forward. Due to the flattening of the LTE system access network, resulting in the disappearance of traditional signaling node, the monitoring of air interface becomes the breakthrough of accurate positioning of the network problems. Therefore, the analysis of the air interface protocol and signaling process, become the most important research direction for the monitoring of LTE system at present.This thesis relies on the National Science and Technology Major Project " New generation broadband wireless mobile communication network ".On the premise of familiar with the 3GPP protocol, using LTE-A air interface monitoring instrument as the research background, design and develope the NAS protocol monitoring module for the LTE-A network, and then, completed the function verification and performance analysis. The main work of this thesis includes the following three parts:1. On the basis of adequate theoretical research, analysis of the overall demand and technology requirements of the LTE-A air interface monitoring instrument, and introduced the architecture design of the monitoring instrument. Then put forward the overall design scheme and realization method of the LTE-A air interface NAS protocol monitoring module. The monitoring of the protocol is made of message decoding module and the synthesis module, etc.2. Each function module is designed and developed respectively. Considering the special format of the NAS protocol message, the modular design idea is used in decoding module to package each decoding function to analyze the protocol; The function of the synthesis module is to associate different messages from the same communication process, then get a complete communication process from the establishment to the end.3. The function test on each module of the designed monitoring scheme has been done through the data of NAS message. The test result is analyzed, it can be shown that the proposed scheme is feasible and can monitor the NAS protocol effectively.At the end of this thesis, the research results and the work which have been completed are summarized; then the imperfect parts of the subject context and prospects for current research are analyzed.