QAM解调及频偏估计联合算法

JOINT ALGORITHM OF QAM DEMODULATION AND FREQUENCY OFFSET ESTIMATION

针对在水声传输环境下,载波频率偏移会导致较大的传输误码率的问题,提出一种能够同时进行载波频率偏移估计以及QAM解调的联合算法。在频域将接收信号样点与标准正弦信号进行最小二乘逼近,通过估计接收信号的频率实现载波频偏估计;同时得到接收信号的幅度和相位,从而得到QAM调制信号的I分量和Q分量系数。仿真证明,该算法降低了QAM调制解调算法的误码率。

In underwater acoustic propagation environment,the carrier frequency offset result in a large transmission error rate. This paper proposed a joint algorithm that can simultaneously perform carrier frequency offset estimation and QAM demodulation. In the frequency domain,the received signal sample points were approximated by the least squares with the standard sinusoidal signal,and the carrier frequency offset was estimated by estimating the frequency of the received signal. The amplitude and position of the received signal were obtained,thus the I component and Q component coefficients of the QAM modulated signal were obtained. The simulation results show that the proposed joint algorithm reduces the bit error rate of QAM modulation and demodulation algorithm.