Subspace-Based Blind Channel Estimation for OFDM Systems with Conjugate-Symmetric Property

A subspace-based blind channel estimation algorithm for OFDM systems with the conjugate-symmetric property is proposed in this paper. In subspace-based algorithms, construction of the signal or noise subspace is an important issue. Different to other subspace-based approaches exploiting the signal or noise subspace from cyclic prefix, virtual subcarriers, or oversampling techniques, we develop a blind channel estimation algorithm by establishing noise subspace from time-domain real symbols, which can be obtained by using the conjugate-symmetric property of OFDM symbols in frequency-domain. Simulation results demonstrate that the proposed algorithm outperforms conventional subspace-based channel estimation algorithms in mean-squared error.