Design And Implemention Of Core Modules For L2 Layer Of Special-Using Small Base Station

The LTE protocol stack is the current mainstream communication protocol stack.The LTE-based communication base station meets people's daily mobile communications' demands,and it is also widely used in various fields such as security,military and Internet of Things.The LTE protocol stack consists of Physical Layer,Data Link Layer and Network Layer.The Data Link Layer is also called L2 Layer.The Media Access Control(MAC)sublayer is at the bottom of the L2 Layer.The Physical Random Access Channel(PRACH)management and the Hybrid Automatic Repeat reQuest(HARQ)management in the MAC layer play an important role in the random access process and uplink data transmission.This article mainly focuses on the special-using scenarios of small base stations.Based on the FSL9131 embedded development board,the PRACH channel management module and the uplink HARQ management module in the MAC layer are implemented under the software level to ensure that the random access process and uplink HARQ process are executed correctly in the special-using scenario.This article begins with a brief overview of the LTE MAC sublayer and introduces its main features.The PRACH channel management module and the uplink HARQ management module are derived,and then the random access process is analyzed in detail.At the same time,the PRACH channel and the uplink HARQ process are deeply studied and analyzed laying the theoretical foundation for the subsequent design and implementation.In the third chapter of this paper,the functional requirements of the special-using small base station are analyzed,then the PRACH channel management module and the uplink HARQ management module are designed including the functional description of the two modules,the framework and business process,finally the framework diagram and business process diagram are given.According to the design of the third chapter,the two modules are implemented under the software level in the fourth chapter.The implementation includes definition descriptions of variable types,constant arrays,and function APIs in the code.At the same time,the flowchart of the implementation of the function is given,and the function flow is described in detail.After the completion of design and implementation,the two modules are tested in the actual scenario which include random access process and the data transmission process.After that,the test results are analyzed to verify the feasibility of the two modules.In the end,the paper summarizes the content of the full text,analyzes the defects in the design work,looks forward to the future work and determines the future direction and content of the work.