正交频分复用水声通信自适应调制算法

Self-adjusting modulation algorithm for orthogonal frequency division multiplexing underwater acoustic communication

分析预估信道长度对信道估计算法的影响规律,提出利用水声通信均衡恢复信号统计量对信道估计质量评估的方法。通过信道长度自适应修正机制,实现对未知水声信道的高精度估计。针对水声信道造成的正交频分复用子载波特性差异,基于信道估计结果,提出在码元总速率、能量约束条件下,各个正交频分复用子载波速率、功率优化分配的自适应调制算法。与传统的等功率、速率分配算法相比,新算法能够显著提升水声通信系统的误码率性能,通过仿真和实地试验,验证了研究内容的有效性。

Regulations between pre-estimated channel length and estimation precision were analyzed. The estimation quality was evaluated in time using statistics of the equalized signals which can help adjust the length of channel estimation algorithm automatically. In view of the differences among subcarriers caused by underwater acoustic channels, a new algorithm which realized optimum rate and power assignments based on channel estimating results was put forward. Compared with the traditional algorithm which assigned rate and power equally to each subcarrier, the new algorithm achieved better property of bit error rate. Simulations and experiments validate the effectiveness and correctness of the researching contents.