Pre-processed space-time trellis codes with one-bit feedback

Open-loop (no feedback) pre-processing methods for improving the error-rate performance of space-time trellis codes in additive white Gaussian noise (AWGN) and Ricean channels which nearly preserve the performance in Rayleigh channels are proposed in [1]. The rotation based pre-processing preserves the Rayleigh channel performance, whereas there is a small degradation in performance in the power division based pre-processing. This degradation depends on the trellis complexity, and is more pronounced for the lower state trellis codes. In this letter, we propose a one-bit feedback method, that improves the performance of the power division method in Rayleigh channels. Simulation results for a 2 × 1 system show that this improvement is significant for the higher state trellis codes. The one-bit feedback is used to determine which of the two channels has a higher gain, and the higher power is assigned to the corresponding transmitter. © 2005 IEEE.