Complex constellations for WCDMA with transmitter diversity

In this paper transmitter antenna diversity for the downlink of a cellular system is proposed in conjunction with optimum anti-fading diversity. In spectrally efficient transmitter antenna, frequency and time diversity schemes the information bit stream is divided into sub-streams and each sub-stream is transmitted over a different antenna, a different frequency, or a different time slot. The present work provides a fading resistant transmission scheme where a base station uses M₁ antennas and M₂ time slots M=M₁+M₂. The selective transmitter antenna diversity (space diversity) scheme is coordinated with the new pseudo-orthonormal complex rotation matrices (time diversity) to get the highest BER performance for low and medium signal to noise ratio, characteristic of wideband code division multiple access (WCDMA). The modulations considered in this work are QPSK, 8-PSK and 16-QAM