在OFDM水声通信中,由于OFDM系统对频率偏兰的敏感性和水声信道的复杂性,栽波频偏估计显得尤为重要。本文首先研究了Song和Mengali两种频偏估计算法,提出了一种改进的反馈重复频偏估计算法,该算法不仅保持了高精度,增大了估计范围,而且运算复杂度也较小。还在理想条件下对这种改进算法与以上两种算法进行了性能分析比较。此外,还在多径衰落的水声信道下对Song算法和改进方法进行了仿真比较。
Because of the sensitivity to frequency-offset and the complexity of underwater acoustic channel, it is very important to estimate the frequency-offset accurately. This paper discusses the carrier frequency offset estimation technique for OFDM underwater acoustic communication systems. An improved feedback-repeated frequency-offset estimation scheme is concerned based on the comparison and analysis of two prevenient estimation methods. Moreover, this paper comparise the performance of the improved scheme and two prevenient estimation methods. And the simulations of the improved scheme and the Song's method in the underwater acoustic channel with multipath are made. The performance comparison and simulated results show that the improved scheme can obtain high accuracy, wide range and low complexity at the same time.