1. A wireless communications system for estimating performance of a communications channel with co-channel interference, the system comprising: a training sequence generator configured to produce a training sequence preamble in time domain; and a processor having a cross-correlator, a channel impulse response estimator, and a Fast Fourier Transform (FFT) calculator, wherein the cross-correlator cross-correlates raw data in a received signal in the communications channel with the training sequence preamble, the channel impulse response estimator estimates time domain impulse response for the received signal cross-correlated with the training sequence preamble, and the FFT calculator computes frequency domain response from the output of the channel impulse response estimator; wherein the processor uses second order cross-correlation statistics obtained from the output of the FFT calculator to create a channel matrix that estimates performance of the communications channel with co-channel interference.