Full rate space-time turbo codes for general constellations

In this paper, we construct full rate parallel concatenated space-time turbo codes which offer full diversity. The constituent codes of this space-time turbo code are the super-orthogonal space-time trellis codes (SOSTTC (Seshadri et al. (2002)). The iterative decoding of these parallel concatenated codes requires the constituent SOSTTC to be recursive. Hence, we first modify the trellis of the SOSTTC to make the encoders recursive. In order to ensure full rate, puncturing of the outputs of the two constituent SOSTTC codes has to be performed. In order to guarantee full diversity, the rank criterion has to be satisfied. With a recursive encoder trellis construction and uniform puncturing scheme, we construct space-time turbo codes with full diversity at full rate. The constructed space-time turbo codes are for general constellations and for a greater number of transmit antennas as compared to earlier works on space-time turbo codes, wherein the constellation is restricted to BPSK and the number of transmit antennas is restricted to 2 or 3. Simulation results show that the performance of these codes is better than earlier proposed schemes for same bandwidth efficiency.