Optimised constellations for transmitter diversity

In this paper transmitter antenna diversity for the downlink is proposed in conjunction with the optimum fading diversity transform. 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/spl times/M2). These transmissions are coordinated to mitigate the effects of multi-path Rayleigh fading and the mobile receiver can recover the entire M-dimensional transmitted vector as long as the signal energy of at least one coordinate is large enough. The selective transmitter antenna diversity (antenna diversity) scheme is coordinated with the new complex diversity transform (time diversity) to get the highest BER performance for low signal to noise ratio. This scheme offers a significant BER performance improvement over previous M-dimensional fading resistant constellations proposed.