A frequency diversity scheme for OFDM systems based on space-time block coding

In this paper, a frequency diversity scheme for space-time block coded orthogonal frequency division multiplexing (STBC-OFDM) systems is proposed. The upper bound of pairwise error probability (PEP) of the proposed scheme is analyzed. The coding and diversity gain is derived. The result shows that the scheme can simultaneously obtain frequency diversity and space diversity gain. Extensive simulations show that the proposed scheme with two transmit antennas and a single receive antenna almost has the same performance as STBC-OFDM systems with four transmit antennas and a single receive antenna. Under the same symbol error rate (SER) performance, the number of transmit antenna is not required to be increased because of using frequency diversity.