Subspace algorithm for blind channel identification and synchronization in single-carrier block transmission systems

A blind channel identification and synchronization method for single-carrier block transmission system over frequency-selective fading channel is proposed. We employ cyclic prefix (CP) insertion to introduce the redundancy at the transmitter side. As a result, the channel impulse response (CIR) could be estimated in a blind fashion by means of subspace algorithm based on second-order statistics through the exploitation of the redundancy. The condition for identifying CIR along with the proof of uniqueness of CIR estimate is provided regardless of CP length relative to channel order as well as data frame size. We further develop a sorting approach to avert timing offset issue in block synchronization. Numerical results presented performance comparison with orthogonal frequency-division multiplexing (OFDM) systems in terms of bit error rate (BER) and channel estimation error. We also compare with traditional zero-padding OFDM systems in terms of the failure rate of block synchronization.