单声线水声MIMO信道容量的研究

Study of the underwater acoustic MIMO capacity for single sound path channel

本文对水声MIMO(Multiple-Input-Multiple-Output)信道容量受收发阵元数目、间距,收发阵位置、方向,平均接收信噪比以及声速剖面的斜率的影响,在收发阵元之间只存一条声线的情况下,通过WKB近似进行了初步的研究。从计算结果可以看出,当收发阵元对之间只存在一条声线时,阵元间距会对MIMO信道容量产生重要影响:当收发阵元间距足够大时, MIMO系统的信道容量将随着接收信噪比和收发阵元数线性增加,一个m×m的MIMO系统的信道容量将为相应的 SISO(Single-Input-Single-Output)系统的m倍,收发阵的方向也会对MIMO系统信道容量产生较大的影响,另外,收发阵的深度、距离也会对水声MIMO信道容量产生影响,声速剖面的斜率在一般水声信道的声速变化范围内,对信道容量的影响不大。

The dependence rameters of element number, of underwater acoustic MIMO element spacing, array position capacity on the array paand direction, the average receive SNR, and the slope of sound speed profile are studied through WKB approximation when there is only one sound path between each transmit and receive element pair. From the computed numerical results we can see that, array element spacing will have a great effect on the MIMO capacity： if the transmit and receive array element spacing are sufficiently large, MIMO capacity will increase with array element number linearly, and the capacity of a m×m underwater acoustic MIMO system is approximately rn times of that of a SISO channel. The direction of the transmit and receive array will also have a big effect on MIMO capacity; furthermore, the depth and horizontal range of the transmit and receive array will have some effects on the capacity. To the effects of the slope of the sound speed profile, it was not very big within the variation range of sound speed in the general underwater acoustic channel.