SPACE-TIME CODES FOR HIGH DATA RATE WIRELESS COMMUNICATION - PERFORMANCE CRITERION AND CODE CONSTRUCTION

We consider the design of channel codes for improving the data rate an d/or the reliability of communications over fading channels using mult iple transmit antennas. Data is encoded by a channel code and the enco ded data is split into n streams that are simultaneously transmitted u sing n transmit antennas, The received signal at each receive antenna is a linear superposition of the n transmitted signals perturbed by no ise, We derive performance criteria for designing such codes under the assumption that the Trading is slow and frequency nonselective. Perfo rmance is shown to be determined bg matrices constructed from pairs of distinct code sequences. The minimum rank among these matrices quanti fies the diversity gain, while the minimum determinant of these matric es quantifies the coding gain. The results are then extended to fast f ading channels, The design criteria are used to design trellis codes f or high data rate wireless communication. The encoding/decoding comple xity of these codes is comparable to trellis codes employed in practic e over Gaussian channels, The codes constructed here provide the best tradeoff between data rate, diversity advantage, and trellis complexit y. Simulation results are provided for 4 and 8 PSK signal sets with da ta rates of 2 and 3 bits/symbol, demonstrating excellent performance t hat is within 2-3 dB of the outage capacity for these channels using o nly 64 state encoders.