Subspace-Based Blind Channel Estimation for MIMO-OFDM Systems with New Signal Permutation Method

Subspace-based blind channel estimation for multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems with repetition index has been proposed in the literature. However, the full-row-rank probability of the signal matrix using the MIMO-based repetition index method is extremely low, especially when low-order modulation or few received OFDM symbols are used. In this paper, the MIMO-based repetition index method with a new signal permutation method is proposed. The proposed method solves the problem of previous MIMO-based repetition index method. Additionally, the proposed method performs well even if low-order modulation or few revived OFDM symbols are applied. Simulation results show that proposed method not only has high full-row-rank probability, but also outperforms conventional blind channel estimation approaches in terms of normalized mean-square error (NMSE).