Asymptotic performance of multicode MIMO systems in frequency selective fading channels

We consider multicode multiple-input multiple-output (MIMO) systems that employ multiple streams on each transmit antenna to increase the data rate in fading multipath channels. While it is possible to show that the multi-antenna interference is asymptotically Gaussian for a large number of antennas, in practice, the number of antennas may be small. Therefore, we derive the asymptotic distribution of the multi-antenna interference when the processing gain is sufficiently large. We then derive the performance of the conventional RAKE receiver.