A closed-form semi-blind solution to MIMO-OFDM channel estimation

Semi-blind channel estimation as a combination of the training-based or pilot-assisted method and a pure blind approach is considered to be a feasible solution for practical wireless systems due to its better estimation accuracy as well as spectral efficiency. However, in the existing semi-blind channel estimation techniques, the weighting factor employed to trade off the training-based and the blind criteria has not been appropriately determined. In this paper, a closed-form solution is developed for semi-blind channel estimation of MIMO-OFDM systems. An appealing scheme for the computation of the weighting factor is proposed, leading to an analytical expression for the weighting factor in terms the MSE (mean square error) of the training-based criterion and that of the blind part. A number of computer simulation-based experiments are conducted, confirming the effectiveness of the derived semi-blind solution.