On efficient use of pilot symbols for multi-path channel equalization of QAM signals

We study a classic problem in wireless data communications in which receivers generally rely on training pilots for equalization of multi-path dispersive channel distortions. Traditional equalizers often require a substantial number of pilot symbols for effective channel compensation. To conserve limited channel bandwidth, we investigate novel equalization algorithms that can make more efficient use of fewer pilot symbols. We present a linear programming algorithm that takes better advantage of the QAM constellation. We further exploit the information inherent in the LDPC forward error correction codes within the linear programming framework to improve the equalization performance and convergence properties.