Research And Implementation Of Monitoring Technology For PDCP Protocol In LTE-A Air Interface

With the wide commercial using in LTE-A network, the operators provide users with higher speed and richer information services, but the problems of network quality are gradually increasing. In order to improve the users' experience of network, the operators urgently need to adopt scientific testing methods to optimize the LTE-A network. In recent years, LTE-A air interface monitoring instrument has become the research focus in the field of communication network optimization, the instrument can monitor and analyze the air interface in real time, which provides a powerful technical support for the optimization of LTE-A network. Therefore, the research and implementation of LTE-A air interface monitoring technology is of great significance.Based on the national science and technology major special projects, LTE-A air interface monitoring instrument is considered as research background, the monitoring techniques for PDCP protocol in LTE-A air interface are researched, and PDCP protocol monitoring module in the instrument is designed and developed. The research work includes the following three aspects :Firstly, on the basis of theoretical research, the system requirements and the architecture of LTE-A air interface monitoring instrument are introduced, and the design of PDCP protocol monitoring module is proposed. The scheme adopts the modular design idea, and the functional sub modules can be divided into data processing in PDCP receiving entity, ROHC decompression module and PDCP protocol decoding module.Secondly, the design and realization process of each module are analyzed. The data processing in receiving entity includes DRB data processing mapped to RLC AM, DRB data processing mapped to RLC UM, and SRB data processing. ROHC decompression uses LSB/WLSB algorithm to decompress the compressed ROHC packet received by PDCP layer, and restores it to the original packet. The PDCP protocol decoding module adopts the idea for separating the decoder and the base decoder, it extracts the key fields of PDCP PDU, and translates the key fields into logical informatio n which can be identified by users.Thirdly, combined with the test data of PDCP protocol, the functions of PDCP protocol monitoring module are verified and analyzed. The results show that the proposed design can accurately and effectively implement the decompression of different types of compressed packets and the key field decoding of various forms of PDCP PDU.Currently, the PDCP protocol monitoring module runs stably in the experimental test environment, it achieves the goal for monitoring the PDCP protocol data, and provides the effective data support for the upper application module.