Rate-2 Space-Time Block Code with Phase Rotation

The full rate and full diversity could be achieved by Rate-2 space-time block code, whereas the decoding complexity is proportional to the square of the modulation order. A rate-2 space time block code with phase rotation is proposed in order to reduce the decoding complexity. Part of the transmitted signals is rotated by a certain angle, and the pairwise orthogonal between the transmitted signals is realized in the proposed scheme, so that the decoding complexity is proportional to the modulation order. Simulation results demonstrate the decoding complexity is reduced greatly by proposed code only with 7 bit feedback.