Adaptive spatial-subcarrier trellis coded MQAM and power optimization for OFDM transmissions

Space-time coding or coded modulation has demonstrated that significant increases in system capacity and performance can be achieved by incorporating multiple antennas at the transmitter and (optional) multiple antennas at the receiver. In this paper, we propose an adaptive spatial-subcarrier trellis coded modulation using MQAM for orthogonal frequency division multiplexing (OFDM) transmission by using instantaneous channel state information and employing multiple antennas at both the transmitter and the receiver. In particular, our objective is to minimize the total transmit power required for each OFDM transmission, by optimizing the power allocation, code rate and modulation scheme in each spatial-subcarrier channel, while maintaining a given data rate and bit error probability. To illustrate the potential of our proposed system, Monte Carlo simulation results are provided