Semiblind channel estimation and equalization for MIMO space-time coded OFDM

• Published in: IEEE transactions on circuits and systems. I, Regular papers Vol. 53; no. 2; pp. 463 - 474
• Main Authors: Yonghong Zeng, Lam, W.H., Tung Sang Ng
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.02.2006; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Ambiguity; Bandwidth; Blind; Channel estimation; Channels; Equalization; Frequency division multiplexing; Frequency domain analysis; Frequency estimation; Mathematical analysis; Matrices; Matrix methods; MIMO; multiple-input-multiple-output (MIMO); multiuser; OFDM; Orthogonal Frequency Division Multiplexing; orthogonal frequency-division multiplexing (OFDM); Pilots; Receiving antennas; semiblind; space-time coding (STC); subspace; Symbols; Transfer functions; Transmitting antennas
• ISSN: 1549-8328; 1558-0806
• DOI: 10.1109/TCSI.2005.856671

Based on the special features of space-time coding (STC) and orthogonal frequency-division multiplexing (OFDM), it is mathematically proved that all channel responses of a multiple-input-multiple-output STC-OFDM system can be identified blindly subject to two ambiguity matrices with a subspace-based method. A method is then presented to resolve the two ambiguity matrices by using few pilot symbols. With the estimated channels, a frequency domain approach is presented to recover the transmitted symbols. The presented semiblind algorithms are valid even if the channel transfer functions are not coprime and do not require precise channel order information (only an upper bound for the orders is required).