水下声信道波通信自适应传输技术

The Self-adaptive Transmission Technique for Underwater Acoustic Channel Communication

主要研究了水下声信道(UACh)可靠通信的数据传输技术。如果水声信道的参数是可估计的并且该估计值能即时反馈回发射机,则接收机就能够根据信道的变化调整传输方式。研究假定一个在慢变的UACh上的固定声源和接收装置,在此UACh上先传输大量的瞬时信噪比恒定信号,然后按瑞利衰落分布改变信噪比值。由信道容量的理论推导表明,可以通过优化数据传输速率来实现发射功率随信噪比改变,但受平均功率条件限制。仿真研究也表明,利用自适应技术,能够较好地适应UACh通信的信道变化,此外,低频情况下坡地坡度的改变对信道容量的影响是不容忽视的。

In this paper, a self-adaptive underwater acoustic channel transmission technique for reliable communica tion is studied. If the acoustic channel parameters can be estimated and sent back to the transmitter, the transmission scheme can he adapted to the channel variation. With aim to verify this technique, we assume a fixed source and receiver over a slowly varying UACh, firstly, the signal to noise ratio （SNR） is fixed after a large number of data transmitted, then, SNR change to a new value based on the Rayleigh fading distribution. Theoretical derivation of channel capacity （ChC） shows that the data rate can be optimized allowing the transmit power to vary with SNR. Simulation result shows that using self-adaptive technique, we can adapt to the channel variation in UACh communication, also we found that the channel is influenced extremely due to the change of the slope angle at the low frequency case.