The Design And Implementation Of L-band CMMB Signal Demodulation/Demultiplexing Module

In the context of triple play,based on China Mobile Multimedia Broadcasting(CMMB),China Satellite Communications Group Co.,Ltd.(China Satcom)began the establishment of L-band CMMB signal wireless LAN push system.The system mainly includes CMMB launch front end construction,CMMB signal receiving module,CMMB signal demodulation demultiplexing module,server building and cloud application store development and other sub-projects.Among them,this subject is derived from the system CMMB signal demodulation demultiplexing module.In the establishment and elaboration of the module,the main work of this paper is as follows:1.Firmware developmentThe firmware development research applications can be divided into parts of the design,development and driving three main designs.Application of research design includes a data processing section,command processing,data input,format data processing functions;driven development research includes SDIO(Secure Digital Input and Output Card),SPI(Serial Peripheral Interface),IIC(InterIntegrated Circuit and other peripheral interface device driver development;The main program design for the main loop queue and procedures for maintenance and guidance.Among them,the main program package TP3005 chip control commands,RDA5815 S chip tuning system control parameters,including the completion of the tuning system initialization,frequency settings and other functions,and provide the relevant service to the application layer call.2.Demodulate module performance and functional testingPerformance testing is a separate test of the demodulation module,requiring the current module performance to achieve CMMB certification test standards.The test items mainly include: sensitivity test,carrier-to-noise ratio threshold under the condition of additive white Gaussian noise channel,anti-jamming test and carrier-to-noise ratio threshold test under dynamic multipath channel condition.Compared with the performance test,the functional test is in the entire L-band CMMB signal wireless local area network(WLAN)push system for each sub-module for the joint test,the purpose is to view the work of the various modules collaboration,to achieve design demand.According to the test content,functional test items can be divided into: single service reception test,full time slot QPSK(Quadrature Phase Shift Keying)receiver test,the whole slot into the two 16QAM(Quadrature Amplitude Modulation)receiver test.Based on the above research and establishment of the module,the push system can provide users with real-time or non-real-time data push service,and makes the system have advantages with rich in content,wide coverage,high transmission rate,indoor and outdoor positioning characteristics.In summary,the realization of this project can provide a new technical basis for CMMB network,which has important application value and significance for demodulation and demultiplexing of L-band signal.