OFDM水声通信信道估计技术研究

Study on channel estimation technique of OFDM underwater acoustic communication system

水声信道是一种极其复杂多变的时—空—频变信道,其信道窄、强多径干扰、信号起伏衰落严重,一直是水下信息可靠高速传输的主要障碍。正交频分复用(OFDM)是近年来数字通信中流行的一种并行传输新技术,其核心思想是将整个可用频带分割成多个正交子信道,将待传输的高速串行码流并行地调制在这些子信道载波上。主要研究利用三种不同的导频图案对OFDM水声通信信道进行估计,并通过仿真的方式来分析不同导频图案下信道估计的性能。

The underwater acoustic channel is very complex where cochannel interference, doppler frequency offsets, narrow bandwidth, serious multi-path time delay interference and frequency selective deep fades obstruct the development of high speed and fidelity underwater data transmissions. Orthogonal frequency division multiplexing （OFDM） is a kind of novel parallel transmission technology. The principle of OFDM is that the whole bandwidth can be divided into some orthogonal sub-channels; the high-speed serial signal stream is modulated by some orthogonal sub-carriers. In this paper, we mainly discuss three different pilot structures on channel estimation in OFDM underwater acoustic communication system and analyze the performance of channel estimation based on different pilot structures by simulation.