Channel equalization with adaptive filtering and the preconditioned conjugate gradient algorithm

Communication system performance is often degraded by the imperfections of the channel. Additive noise, and actual channel characteristics can be unknown prior to transmission. Use of adaptive equalizers to compensate for these imperfections can significantly improve the performance of the overall system. For highly-correlated received sequences, convergence rate of these equalizers is a strongly limiting factor. This paper presents a novel scheme employing the use of the pre-conditioned conjugate gradient algorithm for channel equalization. Simulation examples are presented for channel equalization problems comparing performance of the LMS algorithm to the pre-conditioned conjugate gradient algorithm for algorithms which minimize the mean square error and the constant-modulus criterion