Fading-resistant transmission from several antennas

In a mobile environment, where Rayleigh fading can severely affect the transmission quality of a communication link, diversity schemes are normally considered. Given a transmitter with L antennas, transmissions from the antennas can be designed in such a way as to allow the receiver to estimate the data sent along all L links, even when the signal quality along several links is very poor, with no bandwidth cost. This paper describes a method of generating bandwidth-efficient L-dimensional signal constellations which are resistant to fading and compares these constellations to other fading-resistant constellations that have been proposed before. Comparison is made with the bandwidth-costly method of transmitting identical bit streams in each of the antennas. Another scheme, in which the transmitter receives feedback from the receiver and uses only the best antenna, is also considered