Channel Estimation Using Dedicated Pilot for Transmit Beamforming in OFDM Systems

This paper considers the channel estimation scheme using dedicated pilot signal in orthogonal frequency division multiplexing systems. To this end, we design a novel beamweighted channel estimation scheme, called affine minimum mean squared error (AMMSE) estimator, for transmit beamforming. Although the use of dedicated pilot can provide merits such as the reduction of pilot signaling overhead and boosting of pilot power, it is not often employed in practical estimation schemes. This is mainly due to the difficulty in estimating the statistics of beamweighted channel from dedicated pilot signal. To alleviate this problem, we analytically estimate the statistics of beam-weighted channel from those of common pilot channel. Then, we consider an AMMSE estimator that can improve the estimation accuracy by utilizing the statistics of beam-weighted channel. Simulation results show that proposed estimation scheme remarkably outperforms conventional estimation schemes particularly near the cell boundary.