Space-Time Block Codes Based on Diagonalized Walsh-Hadamard Transform with Simple Decoupling

This paper presents space-time block codes (STBC) constructed by the orthogonalization of Walsh-Hadamard transform domain coefficients. The novel Walsh-Hadamard STBC (WHSTBC) provides full rate and full diversity order when the number of receive antennas is at least equal to the number of transmit antennas, with appropriate pre-coding of the PSK or QAM modulated symbols. Hadamard matrices exist for orders equal to N = 2ⁿ, where n ≥ 1 and lead to square WHSTBCs with minimal delay. The structure of WHSTBCs allow for simple decoupling and decoding. Simulation results and performance analysis are presented for N × N matrices with N = 2, 4, and 8.