A MIMO-OFDM scheme with full-diversity in frequency for time-varying channels

The project of wireless communication systems with the purpose to minimize the bit error rate is a current problem and it is motivated increasingly by the growing demand for higher data rates. In this sense, this work proposes a frequency, time and space diversity technique, which applies a space-time code with block repetitions such that space-frequency diversity is obtained, combined with the time spreading of OFDM symbol through Hadamard transform. Simulations showed that performance gain was achieved in high Doppler frequency scenarios followed by improved results at degraded frequency selective fading channels modeled by Rayleigh distributions.