Research And Test Of MAC Layer For UE In 5G NR Systems

Currently,the fifth Generation mobile communication technology(5G)has undoubtedly become the hot point of communication field with the iteration and update of mobile communication technology.Relevant 5G terminal products have been transformed from theory to business.Medium Access Control(MAC)layer plays an important role during the development of 5G terminal.Its R&D maturity would reflect developers' understanding of key technologies for 5G systems,and determine the competitiveness of terminal products.Therefore,this thesis takes the research and test of the MAC layer for UE in 5G systems as the entry point,verifying the protocol conformance of MAC layer function realization,and providing support for the improvement of the terminal products.This thesis relies on the major theme special project of Chongqing Science and Technology Commission,”R&D and Application of 5G Terminal Simulation Equipment”.The project aims to develop one terminal system conforming to the requirements of 3GPP Release 15 protocol,and realize data iteraction and testing for g NB.This thesis focuses on the new features of random access,Hybrid Automatic Repeat Request(HARQ)and channel multiplexing in the MAC layer of 5G systems,taking the entity architecture and main functions of MAC layer as research project.The rationality and protocol conformance of document design,code implementation and exception handing of MAC layer for UE in 5G systems are verified.In combination with the characteristics of protocol stack project development and test,the parallel test model is adopted to synchronize the design and implementation of MAC test with that of the whole project.Considering the current implementation schedule of the project,the MAC single-layer test scheme is adopted to analyze the MAC test objectives,divide the test stages,and define the test design and implementation steps.Based on the function research of MAC layer,the test demand of test set for MAC layer is listed.Besides,the test set scheme of MAC layer is designed with modularization,including terminal and MAC test state,test interface,and test timer.On the basis of the test demand analysis on MAC layer,proper test flow is designed,and classic gray box test method is used to design test cases,which reflect the meticulous design ideas from whole to part.Based on the architecture of PC+DSP+FPGA hardware and the role that MAC plays in the process of terminal signaling message interaction,the construction of MAC single-layer test platform architecture for PC+DSP is built.The test set is implemented by CCS5.5 and Visual Studio 2012 software environment and TMS320C6678 hardware baseband development board.After hundreds of test verification analysis and code modification,it is finally confirmed that the test cases designed can cover the main functional process of the MAC layer.The comprehensive code coverage of the cases takes up more than 94%,and the test success rate of the implementation code reaches up to 100%.It confirms the rationality and completeness of test set design and implementation.At the same time,the protocol conformance of MAC layer function implementation is also verified.