Research And Implementation Of Physical Layer Interface Of Special Small Base Station

Compared with the previous mobile communication technologies,the LTE technology has the advantages of wide spectrum,fast rate and low delay,and can provide higher speed,more stable and richer data services.For daily communication,and the scope of application is expanding in many fields such as security,education,defense,and media.With the development of mobile communication technologies,the advantages of high integration,easy portability,easy installation,and strong environmental adaptability of small base stations have been further developed and applied to private networks and specific environments.The work done in this article is based on the special small base station development project in the field of public security.The core of the research is the interaction between the physical layer and the upper layer of the eNodeB.According to the 3GPP standard protocol,the LTE technology is deeply analyzed,the specific functions are mastered,and the physical layer interface of special small base station is designed and implemented.Firstly,this thesis gives a brief overview of the overall architecture and protocol stack of LTE system,introduces the functions of physical layer and MAC layer respectively,and focuses on the analysis of the interaction process between physical layer and MAC layer,which provides a theoretical basis for the design of physical layer interface module of special small base station.Secondly,according to the functional requirements of the physical layer interface,the overall architecture design of the interface module is given and divided into three parts: the physical layer control module,the data processing module and the transceiver control module.In the design,the functional framework and business processes of the three sub-modules are described respectively.Then,according to the previous design scheme and the 3GPP protocol,the software level implementation of the physical layer interface module of the special small base station is carried out,including the detailed structure description of the interface message,and the definition and detailed flow of some core functions are given to realize the function of the interface module.Finally,after the design and implementation,a dedicated small base station test environment is built on the NXP BSC9131 hardware platform.The physical layer and the upper layer perform functional tests on the physical layer interface module,and the test content mainly includes the UE access function and the data transmission process.The physical layer interface message forwarded by the transceiver control module is captured by the wireshark software,and the structure of the interface message and the timing of the interaction are analyzed in combination with the content of the packet capture.The analysis results are consistent with the design of this paper.It can be seen from the test results that the physical layer interface basically realizes the data interaction between the physical layer and the upper layer,and achieves the basic requirement of returning the real-time video of the specified terminal device.