The Debugging And Realization Of OFDM System Based On DSP And FPGA Hardware Platform

Orthogonal Frequnency Division Multiplexing(OFDM) is suitable for high rate data transmission in wireless channels because it can combat Inter-Symbol Interference and multipath fading efficiently.With urged demand on the digital,wideband,personal and mobile communication,OFDM has become one of the hottest topics in this field.So it can be estimated that OFDM will be applicated significantly in B3G or 4G systems.Referenced on the standard IEEE802.11a PHY specifications,this paper focuses on the accomplishment of an adaptive modulation and demodulation OFDM communication system.The hardware structure is based on the"DSP+FPGA+DUC/DDC"architecture of Software Defined Radio,which makes the AD/DA close to the intermediate frequency and reduces the analog processing.In this paper,we first introduce the OFDM system architecture,functional partitioning,frame structure and parameters.Following this,we focus on the debugging of the chips on the board.Then,we study how to program in the DSP plus FPGA platform to achieve the adaptive modulation and demodulation OFDM system.In the end,the system performance is tested,including the test of adaptive modulation and demodulation,the measurement of the spectrum of the OFDM signal,which is under the IEEE802.11a emission mask and the demodulation performace.All the BPSK,QPSK,8PSK and 16ΑM demodulation constellation plots are in good status that our system can transmit data adaptively.