Adaptive antenna arrays for the co-channel interference cancellation in OFDM communication systems with virtual carriers

We propose a blind beamforming algorithm for OFDM based communication systems. After applying the DFT operation to the output of each antenna, one estimates the signal plus interference spatial correlation matrix by selecting the samples at the "non-zero valued" subcarriers, and the interference-alone spatial correlation matrix by choosing those samples at the "zero valued" subcarriers (also known as virtual carriers). It was shown that the beamforming weight vector yielding the optimum signal to interference plus noise ratio is the "largest" generalized eigenvector of the resulting matrix pencil. The simulations presented here employ an OFDM signal model to illustrate the efficiency of the proposed algorithms.