Design And Implementation Of PDCP Layer And RLC Layer For 5G Road Tester

With the rapid development of network and information technology,various new services and application scenarios continue to emerge.A new generation of information technology based on 5G will bring new developments to mobile communications.In the large scale 5G network deployment and construction,the outside test workloads are tremendous but indispensable.During the test,as one of the most important testers in the5 G instrument industry chain,the 5G road tester can be used to evaluate the quality of the5 G network,provide reliable mass data sources and analyze data in the process of exploring new signals,scenarios and topological structure.This thesis relies on a major theme topic "R&D and Application of 5G Road Test Instruments" in Chongqing.The Packet Data Convergence Protocol(PDCP)and Radio Link Control(RLC)layers of the 5G protocol stack are designed and implemented based on the R15 protocol standard and practical requirements of the Third Generation Partnership Project(3GPP).The main research content includes the following three aspects:1.Based on the research of 5G network architecture and protocol stack.,the functional requirements and system architecture of the 5G road tester are clarified,and the PDCP/RLC layer design requirements for the road tester are also proposed.Then,a comparison is made between the PDCP/RLC layer protocols in the 5G system and the LTE system.The PDCP/RLC entity state is divided based on the state transition mechanism.Finally,the control plane and user plane data transmission channels and interlayer interfaces are designed.2.For design,a modular scheme is proposed to realize the protocol stack software.Protocol stack tasks are divided and assigned corresponding module.Firstly,research and implement the PDCP/RLC entity configuration scheme under the multi-instance mechanism.At the same time,PDCP and RLC Acknowledged Mode(AM)entity uplink/downlink data transmission and functional function module codes are implemented.Among them,for RLC unacknowledged mode(UM),a protocol data unit assembly and transmission method is proposed,which reduces the number of segments and segment overhead and improves the utilization of wireless resources.Specifically,the functional modules include the integrity protection/verification,encryption/decryption of the PDCP layer,the data fragmentation algorithm and status report of the RLC layer and interface functions.3.Finally,two stages of testing and verification analysis are carried out.Firstly,test the PDCP/RLC single layer by writing test cases.Secondly,put the code in the DSP and connect it with the connection tester for system testing,and then extract the air interface uplink/downlink data,status report and MIB for data analysis under wireshark.The test and analysis results verify the correctness and protocol consistency of the design and implementation of the PDCP/RLC layer in this thesis.It meets the project's expected goals and provides an effective support plan for 5G network construction and test optimization.