Multiple Antennas in Random Code CDMA Systems: Transmission, Detection and Spectral Efficiency

We investigate the use of multiple antennas at the transmitter and multiple antennas and multi-user decorrelating detectors at the receivers for providing high-speed data on the downlink of cellular CDMA systems. We analyze the system's spectral efficiency by combining link level bit error rate simulations with system level signal-to-interference ratio simulations. We show that using random spreading codes, a spectral efficiency of 3.8 bits/chip/sector can be achieved using 8 transmit and 12 receive antennas, compared to a spectral efficiency of 0.16 bits/chip/sector for a voice system with single transmit and receive antennas.