Channel diagonalization using a full-rate space-time block code

A novel full rate space-time block code that diagonalizes the channel matrix without the channel knowledge at the transmitter is proposed in this research. The main advantage of channel diagonalization is that it allows a simple detection scheme at the receiver end. Our method for channel matrix diagonalization consists of two steps. First, we propose a code structure that can transform the channel matrix to a circulant one. Then, the circulant channel matrix can be diagonalized using DFT and IDFT in the transmitter and the receiver, respectively. The proposed scheme not only diagonalizes any channel matrix with an even number of transmit antennas, but also guarantees that the real and imaginary parts of each received symbol are attenuated equally. Simulation results show that the proposed code structure outperforms the G ₄ code about 2 dB in an environment of four transmit and four receive antennas with the bit error probability equal to 10^-6.