Dynamic Transmit Power Allocation Scheme for Space-Time Turbo Trellis Codes with Partial CSI Feedback

Space-time turbo trellis coding (STTuTC) has been shown to provide a significant performance improvement over comparable space-time trellis coding (STTC) schemes due to an increase in coding gain. In conventional STTuTC schemes equal power is allocated to each transmit antenna. From information theory we know that if partial or full channel state information (CSI) is available at the transmitter, the system performance can be further improved. In this paper we consider the design of a STTuTC scheme where the transmitter has knowledge of the order of channel quality for each transmit antenna. For the proposed scheme, the transmitter allocates the transmit power to each antenna based on this information. A closed-form expression for the pair-wise error probability (PEP) upper bound over quasi-static Rayleigh fading channels is derived. The optimum power allocation coefficients are calculated based on this PEP bound. Simulation results show a significant frame error rate (FER) performance improvement for the proposed scheme with optimal power allocation compared to the conventional STTuTC scheme with equal power allocation