Optimal Code Constructions for SIMO-OFDM Frequency Selective Fading Channels

A SIMO-OFDM system with n_r receive antennas and Q subcarriers is considered in this paper. Under a frequency-selective Rayleigh fading channel with L multipaths, L < Q, it is first shown that the channel capacity of this channel is same as that of the flat Rayleigh fading channel and is independent of the power-delay profiles. It is also shown that the outage exponent equals d_out(r) = Ln_r(1-r). Finally we prove that a newly constructed multi-block space-frequency code can be used to reach the optimal diversity-multiplexing gain tradeoff of this channel with optimal diversity gain d^-(r) sime Ln_r(1-r).