Adaptive antenna arrays using sub-space techniques in a mobile radio environment with flat fading and CCI

We compare the performance of the minimum mean square error (MMSE) and maximum signal to interference plus noise ratio (MSINR) cost functions in a flat fading channel with co-channel interference (CCI). We investigate the reduced rank and full rank weighted sub-space techniques. We observe that using the reduced rank approximation technique on MMSE is equivalent to MRC in a flat fading channel without CCI. For the CCI case we found the full rank weighted sub-space technique applied to MSINR performs best. Through reduced rank approximations of the covariance matrices, the signal sub-space performs well for the MMSE and the noise sub-space performs well for the MSINR. However, the weighted sub-space performance was close to the known rank case and much better than the conventional techniques.