Scalable Design of Space-Time Trellis Code with Low Decoding Complexity

Design of space-time codes that scale with the number of transmit antennas is a difficult problem. In this paper, we introduce a new family of space-time trellis codes (STTC) that can be applied to any arbitrary number of transmit antennas. This family is constructed by utilizing QPSK STTCs as component codes to construct STTCs with larger constellation size. Unlike the design of existing STTC, the search space in our design does not grow exponentially with the constellation size or the number of transmit antennas. Additionally, we propose a practical approach to reduce the computational complexity of our proposed scheme using interference mitigation techniques. Simulation results compare the performance of our approach with that of space-time block codes for the case of two transmit antennas and several different number of receive antennas, a spectral efficiency of 4 bits/s/Hz, and slow Rayleigh fading channels.