MMSE Turbo Equalizer for Channels with Cochannel Interference

The MMSE turbo equalizer has excellent performance with moderate complexity. Current realizations of an MMSE turbo equalizer usually assume the equalizer output is Gaussian, which, however, may not be true for channels with co-channel interference (CCI). In this paper, we first show that, in presence of CCI, a linear pre-whitener is required to decorrelate the CCI-plus-noise. Then we apply density estimation for the residual noise at the equalizer output to further improve the performance. Numerical simulations are also shown to verify the analysis