基于海面散射的莱斯MIMO信道容量研究

Rician MIMO capacity of sea-surface scattered underwater acoustic channel

通过相关莱斯信道模型对海面散射水声多入多出(MIMO)信道容量进行了研究。从Helmholtz-Kirchhoff积分和Fresnel近似出发,得到海面散射信号的空间相关性,由于信道的协方差矩阵不可以表示成发射相关矩阵和接收相关矩阵的Kronecker积,通过Monte Carlo仿真研究了莱斯因子、接收信噪比和空间相关性对MIMO信道容量的影响。从对outage capacity和信道容量的CCDF(Complementary Cumulative Distribution Function)的仿真计算结果可以看出,莱斯衰落的MIMO信道容量并不总是小于瑞利衰落MIMO信道容量,当信道的空间相关性较大和接收信噪比较小时,由于信道的衰落作用将起主要作用,对于较小的收发阵元数,以非衰落的直达信号为主的莱斯MIMO信道容量将大于瑞利衰落的MIMO信道容量。

The effect of Rician Factor （RF） and spatial correlation on the Ricean MIMO capacity is studied based on the sea-surface scattered underwater acoustic Rician fading channel. The spatial correlation of the sea-surface scattered signal is derived with the integrel of Helmholtz-Kirchhoff and the Fresnel approximation. We find that covariance matrix of this channel cannot be expressed as the Kronecker product of the transmit correlation function and the receive correlation function. Therefore dependence of MIMO capacity on RF, received SNR and the factors affecting spatial correlation such as element spacing and wind speed are studied through Monte Carlo simulation. From the simulation results of the outage capacity and CCDF of the capacity, the MIMO capacity of Rician channels is not always lower than that of the Rayleigh channels. When there are strong spatial correlations and low receive SNR, fading is more significant in the MIMO channels. For a small number of transmitting and receiving elements, the Rician MIMO capacity composed mainly of deterministic LOS signal will be greater than the Rayleigh fading MIMO capacity.