Design And Realization Of OFDM Modulator And Transceiver Front-end Based On FPGA

Because of the high spectral efficiency,the orthogonal frequency division multiplexing(OFDM)technology has been widely used in various fields of communication technology.On the one hand,in the field of mobile broadcast television for continuous transmission,the next generation mobile broadcasting standard blueprint DVB-NGH was proposed in2012 in order to alleviate the contradiction between people's growing demand for multimedia services and limited spectrum resources.DVB-NGH greatly improves the throughput and coverage of the mobile broadcast television network without the update of the existing networks,so it is widely concerned.On the other hand,the OFDM system for burst transmission is one of the popular directions of OFDM technology because of its high design freedom and scene adaptability,especially for some special environment.Based on the above considerations,the modulator IP cores of a continuous OFDM system for DVB-NGH standard and a burst OFDM system based on proposed intelligent Triple-Adaptive technology is designed by the paper.A FPGA-based data transceiver platform is also established by the paper.The specific work of this paper is as follows:1.The paper summarizes the emergence and development of OFDM technology,introduces the application of OFDM technology in various communication technology fields,and highlights the application of OFDM in mobile TV broadcast both at home and abroad.2.The paper is in depth research and analysis of DVB-NGH basic profile and key technologies.According to the special frame structure and the new BICM structure of DVB-NGH,a hardware implementation scheme of a continuous OFDM system modulator for DVB-NGH standard is designed.Based on the existing BICM scheme of DVB-T2 standard,the bit-interleaved coding modulation of DVB-NGH standard is implemented.Modelsim simulation proves that it supports most of conventional transmission modes defined by the standard.3.In view of the fact that the existing terrestrial communication technology has difficulty in supporting the reliable communication in the extreme scenarios,this paper proposes an intelligent Triple-Adaptive transmission scheme for burst transmission.By adding several feedback bits,it can deal with various links with different SNRs and multipaths,save the power consumption of the equipment and solve the problem of link interruption caused by multipath delay.On the basis of this,a modulator IP core based on the burst OFDM system is designed according to the project requirements,whose results meet the design requirements.4.In order to evaluate the performance of the entire communication system,including the modulator,we use a xilinx ZC706 evaluation board to establish a FPGA-based data transceiver platform with an AD9361 FMC daughter card as the RF transceiver front end.The platform supports not only SDR-based wideband wireless data transceiver for wireless transmission verification in real laboratory environment,but also inter-board direct transmission of baseband data through optical fiber for the verification of baseband transmission link.