Open-loop transmit diversity of downlink CDMA systems over Rayleigh fading channels

We consider transmit diversity for a downlink multiuser CDMA system with distinct signature waveforms assigned to distinct antennas. We derive an upper bound of error probability and propose a new class of signature waveforms with which we can achieve the same BER as a system with orthogonal spread sequences for the number of user near to the processing gain. The proposal system is simple to implement and allows a simple receiver.