Blind estimation of time-varying (TV), rapidly fading channels is addressed in this paper, using a basis expansion approach. Each TV coefficient is expanded onto a basis and the expansion parameters are estimated for subsequent use in Viterbi or decision-feedback equalizers. Blind estimation of the expansion parameters is accomplished using higher order statistics. Identifiability of the channel is shown from second and fourth-order TV cumulants of the received signal. A cumulant matching criterion is adopted and instantaneous approximations are proposed in place of the nonstationary ensembles. Linear methods are also derived to initialize the nonlinear optimization procedure. Strong convergence of the proposed method is established. Finally, the method is tested on a simulated mobile radio channel with multipath.
Bibliographical noteFunding Information:
Paper approved by J. H, Winters, the Editor for Equalization of the IEEE Communications Society, Manuscript received February 16, 1993; revised January 31, 1995, and August 17, 1995_ This work was supported by the National Science Foundation under Grant NSF-MIP 9424305. M, K_ Tsatsani� is with the Department of Electrical Engineeriug and Computer Science, Stevens Institute of Technology, Hoboken, NJ 07030 USA. G. B. Giannakis is with the Department of Electrical Engineering, University of Virginia, Charlottesville, VA 22903-2442 USA. Publisher Item Identifier S 0090-6778(96)03353-3.