WLC31-6: Performance Analysis of Multiuser MIMO CDMA Systems in Fast-Fading Channels

The performance of space-time transmit diversity is examined in a multiuser direct-sequence code division multiple access (DS-CDMA) system over fast-fading channels. The underlying space-time system employs two transmit and M receive antennas at the mobile user and receiver base station, respectively. We consider the performance of the space-time multiuser system when using the linear decorrelator detectorto combat the effect of multiuser interference. In our analysis, we derive a closed form expression for the probability of bit error in fast-fading channels. These theoretical results are then compared to simulations where it is shown that they are in excellent agreement. Our results demonstrate that, regardless of the system load, the full diversity order of 2NM for the fast- fading channel is always maintained and only a signal-to-noise ratio (SNR) loss is incurred.