Semi-blind channel estimation on inaccurate noise subspace for MIMO systems

An approach to improve the performance of subspace-based channel estimation for multiple-input multiple-output (MIMO) systems is proposed. In a subspace-based channel estimation method, a small number of received blocks cause the residual error which affects the accuracy of the noise subspace because the covariance matrix is estimated from the received signal to find the noise subspace. To reduce the effect of residual error affecting the accuracy of the noise subspace, a measure called the Hermitian angle is introduced and the receive diversity is exploited based on the iterative algorithm.