高阶调制系统中一种基于经验特征函数的盲AWGN信噪比估计算法

A blind estimation algorithm for AWGN SNR based on empirical characteristic function in high-order modulation system

在Turbo类迭代译码器译码初始化步骤中,需要估计AWGN信道的方差以生成接收比特的先验信息。而已有文献主要针对BPSK/8PSK情形进行研究[1,2],因此本文从经验特征函数的角度出发,推导出高阶调制的低复杂度、盲信噪比估计算法。仿真表明对于各种不同的MPSK/MQAM调制,尽管接收端不知道何种高阶调制,估计器均能获得较好的无偏估计。

In order to retrieve the prior information from the received bits, it is necessary to estimate the variance of AWGN channel during the initialization of Turbo iterative decoder. Some literature have been devoted to this problem in BPSK/8PSK scenarios, and in this paper, we present another low-complexity estimation method based on empirical characteristic function. It proves to be effective for both MPSK and MQAM, and alternatively provides a good un-biased estimation even without the knowledge of modulation type, as we can see in the simulations.