Space-Time Coding over Rayleigh Fast Fading Channels Using Unitary Matrices

This paper aims to provide a new transmit diversity technique for fast fading channels. To this end, a combination of space-time coding and unitary matrices at the encoder side is proposed, showing the maximum diversity gain for the case of 2, 4 and 8 transmit antennas and an arbitrary number of receive antennas can be achieved in such channels. This simplifies the maximum likelihood decoding algorithm, which can be translated to a simple linear processing at the receiver side.