An interference cancelling multichannel matched filter

We consider mobile radio communications with one user of interest and possibly interfering users and noise, over several discrete-time channels obtained either by oversampling or from multiple antennas. The optimal receiver structure for one signal of interest plus spatially and temporally correlated noise is MLSE equalization with an appropriately weighted metric for vector signals. We show however that we can alternatively pass the vector received signal through both a MISO (multi-input single output) matched filter and a MIMO blocking equalizer. The blocking equalizer output is independent of the signal of interest and is used as the input to a MISO Wiener filter that reduces the noise in the matched filter output. The resulting structure is called the interference cancelling matched filter (ICMF). The training sequence of the signal of interest can be used to estimate the corresponding channel, from which matched filter and blocking equalizer can be determined. The remaining quantities can be adapted from the available signals. The performance of the ICMF is analyzed in a number of scenarios. The extension to the case of noncircular noise and interference is developed and is shown to be particularly of interest, in the case of 1D constellations.