Non-parametric trellis equalization in the presence of non-Gaussian interference

We consider the problem of equalization of the frequency selective mobile radio channel in the presence of co-channel interference (CCI). Conventional trellis equalizers treat the sum of noise and interference as additive white Gaussian noise, while CCI is generally a colored non-Gaussian process. We propose a non-parametric approach based on the estimation of the probability density function of the noise-plus-interference. Given the availability of a limited volume of data, the density is estimated by kernel smoothing techniques. Due to the temporal color of the CCI, the use of a whitening filter is also addressed. Simulation results are given for the GSM system, showing a significant performance improvement with respect to the equalizer based on the Gaussian assumption.