多进制正交扩频系统中软信息提取电路的实现

Implement of Extracting Circuit for Soft-information in M-ary Orthogonal Code Spread-spectrum System

在相干多进制正交扩频通信系统中,需要对多路匹配滤波器输出信号进行最大值判决,以利于后级的信道译码.从对数似然比(LLR)出发,提出了一种适用于多进制扩频系统的次最优的软信息提取方法,并仿真验证了该方法在AWGN信道中的性能,最后讨论了在FPGA上实现软信息提取的电路结构.实践表明,这种次最优的软信息提取方法简单实用,便于FPGA实现,并能够有效节约硬件资源.

In the coherent M-ary Orthogonal Code Spread-Spectrum System, the maximal value decision of the output signals from the multiple matched filters is needed before channel decoding. Based on the Log-likelihood Radio（ LLR）, a suboptimal soft-information extracting scheme in the M-ary Orthogonal Code Spread-spectrum System is proposed and the performance of the system in the AWGN channel is analyzed. Then the architecture of the system implemented on FPGA is presented. The practical results indicate that the scheme is effective and can be implemented on FPGA easily and conveniently.