Comparison Study of Low-Complexity Detection Schemes Exploiting Subcarrier Correlation for V-BLAST OFDM

The combination of vertical Bell Laboratories layered space-time (V-BLAST) and orthogonal frequency division multiplexing (OFDM) is a promising solution for realizing spectral efficient transmission in scattered environments and overcoming the frequency-selective fading in broadband radio channels. The exhaustive detection of V-BLAST OFDM, which applies the same detection on individual subcarriers, can lead to satisfying performance at the cost of complexity. In addressing the complexity issue, two low-complexity detection schemes are proposed. Both of them are based on the subcarrier grouping and apply the same detection order to the whole group. The nulling vectors are calculated by Gram-Schmidt orthonormalization (GSO) of the channel matrix at individual subcarriers. We compare the performance of these two detection schemes for a 4times4 system. The simulations are carried out with different modulations, ideal and estimated channel frequency responses (CFR). The scheme (N. Boubaker et al., 2001) is superior since it has lower computational complexity with no significant performance loss compared with (W. Yan et al., 2004)