Design And Implementation Of PDCP Layer And RLC Layer In 5G

5G was born to fulfill people's dream of the interconnection of all things.The communication between the network and the terminal are regulated by the air interface protocol stack.Therefore,the development and testing of the 5G system protocol stack is helpful for the research and market application of 5G technologies and products.Relied on the Chongqing Municipal Science and Technology Commission's major theme project "R & D and Application of 5G Terminal Analog Equipment",this thesis studies the PDCP and RLC of the 5G system protocol stack.In order to realize the PDCP and RLC technologies that meet the 5G standard,this thesis adopts the protocol stack development method of requirement analysis,design,implementation and testing.Through in-depth study of the protocol specifications of PDCP and RLC,comparing LTE-A,the data transmission process and the PDU frame format are analyzed.The 5G PDCP adds PDCP replication and user plane data integrity protection functions.The 5G RLC abandons the SDU concatenation and reordering functions,and remains the SDU segmentation and reassembly functions and ARQ process,and pre-process the data before the lower layer indicates the transmission opportunity.By designing the inter-layer interfaces and interface primitives,the functions of PDCP and RLC activation of the access layer security process,application and notification of transmission opportunity and resource,data flow control,entity establishment,and data transfer are implemented.By designing the states of PDCP and RLC,the different stages of PDCP and RLC are distinguished.By designing the control plane and user plane data transmission process,the data interaction between layers is implemented.By designing the multi-instance management mechanism,the independent operation of multi-entity at PDCP and RLC are implemented.Then,building the protocol stack developing platform,applying the principle of finite state machine and polling queue,the establishment of PDCP and RLC entities,the data transmission channel of PDCP and RLC are realized by coding in C language.Finally,write test cases to test the PDCP and RLC,which are designed and implemented in this thesis.A total of 30 test cases are designed for the maintenance of the sequence numbers of the PDCP and RLC,the security functions of the PDCP,the segmentation and reassembly of the RLC,and the ARQ process,and the data transmission process of the PDCP and RLC.Improved through trial and error,the test results of all test cases are consistent with the protocol specifications,and test case pass rate reaches 100%,which verifies the rationality and feasibility of the PDCP and RLC designed and implemented in this thesis.