Two signaling schemes for improving the error performance of frequency-division-duplex (FDD) transmission systems using transmitter antenna diversity

Two signaling schemes that exploit the availability of multiple (N) antennas at the transmitter to provide diversity benefit to the receiver are proposed. In the first scheme, a channel code of length N and minimum Hamming distance d_min ⩽ N is used to encode a group of K information bits. The channel code symbol c_i is transmitted with the i^th antenna. At the receiver, a maximum likelihood decoder for the channel code provides a diversity of d_min, as long as each transmitted code symbol is subjected to independent fading. The second scheme introduces deliberate resolvable multipath distortion by transmitting the data bearing signal with antenna 1, and N - 1 delayed versions of it with antennas 2 through N. The delays are unique to each antenna and are chosen to be multiples of the symbol interval. At the receiver, a maximum likelihood sequence estimator resolves the multipath in an optimal manner to realize a diversity benefit of N