The effect of space-time joint correlation on the underwater acoustic MIMO capacity

The joint effect of space and time correlation on the underwater acoustic Multiple-Input-Multiple-Output (MIMO) channel capacity is studied using the multipath space-time correlation model with a moving transmit array and a stationary receive array. The space-time correlation function of the uniform liner array is generated, which can be expressed as the production of the space correlation function and the time correlation function, so the space-time joint correlated complex Gaussian variates can be generated by firstly generating n/sub T/*n/sub R/ independent random variates with the desired autocorrelation function, and then multiplied by the square root of their cross-correlation matrix. Using Monte Carlo simulations, the effect of space and time correlation on the underwater acoustic MIMO capacity is studied by the parameters of transmitter velocity, array element spacing, and elevation angle spread. It is shown from the simulation results that in the case of a poor scattering environment and not sufficiently large element spacing, when n transmitter elements and n receiver elements are employed, the outage capacity will not increase linearly with the increasing of n, and large capacity gains can only be obtained in a rich scattering environment and with sufficiently large element spacing, and the effect of transmitter velocity on the capacity depends on the block length T, when T/spl Gt/T/sub coh/, capacities with different transmitter velocity will be the same.