用于OFDM调制解调模块的设计与实现

Design and Implementation of Universal Modulating-Demodulating Module in OFDM System

比较了正交频分复用(OFDM)中常用的四种调制解调工作模式,并对BPSK、QPSK、16QAM和64QAM四种调制方式的通用调制解调模块进行了优化设计,使之能根据接收端的误码率状况进行自动调整调制,采用共享64QAM映射表整合16QAM映射表ROM,通过对BPSK和QPSK的解调分析,由于星座点比较少,判决最后可以转换成映射关系,并将实部和虚部分别进行。利用共享寄存器、数据选择器、减法器等器件进行数据优化整合运算。通过FPGA的仿真,对几种调制模式的资源消耗进行比较,在不影响性能的基础上优化后的资源占用得到极大降低。

Compared four modulation and demodulation modes used in OFDM （orthogonal frequency division multiplexing）, the optimized system was designed for universal modulating-demodulating module based on the BPSK, QPSK, 16QAM and 64QAM to enable it adjust modulation automatically according to the BER status of receiving port. Though BPSK and QPSK demodulation analysis, sharing 64QAM mapping table integrated 16QAM mapping tables, adjudication may be converted mapping and processed real-imaginary part respectively. The public ROM, public register, subtracted and selector were used for optimized integration computing. Through the FPGA simulation, compared several modulation modes, the hardware resource of the optimized system was reduced greatly without influence on performance.