A block-by-block blind post-fft beamforming algorithm for multiuser OFDM systems based on subcarrier averaging

This paper considers blind beamforming of multiuser orthogonal frequency division multiplexing (OFDM) systems. Assuming that the channel is static within one OFDM block, a blind post-FFT multistage beamforming algorithm (MSBFA) based on subcarrier averaging over one OFDM block is proposed, which basically comprises: i) source (path) extraction using a hybrid beamforming algorithm composed of a Fourier beamformer and a kurtosis maximization beamformer, ii) time delay estimation and compensation, iii) classification (path-to-user association) and blind maximum ratio combining (of paths). The designed beamformer effectively utilizes multipath diversity for performance gain, and is robust against the effects of correlated sources. Some simulation results are presented to demonstrate the effectiveness of the proposed MSBFA.