Optimum 4-Transmit-Antenna STBC/SFBC with Angle Feedback and a Near-Optimum 1-Bit Feedback Scheme

A 4-antenna transmit diversity scheme based on space time/frequency block coding (STBC/SFBC) with 1-bit feedback is proposed. We first describe the optimum scheme with angle feedback. We then identify the condition under which choosing between only two choices of angles effectively eliminates the larger between the real and imaginary parts of the interference term. Simulation shows that the 1-bit feedback scheme achieves near-optimum performance.