Subspace-based tracking of multipath channel parameters for CDMA systems

In this paper, we evaluate several issues in the application of subspace based methods to tracking channel parameters in Code Division Multiple Access (CDMA) communication systems, in the presence of multipath fading. We focus on two aspects of the problem the performance of Singular Value Decomposition (SVD) based schemes while tracking the time variations in the signal subspace, due to fading, and, the performance tradeo involved in using several complexity reducing approximate schemes. The performance bene ts to be obtained from application of subspace based methods to channel estimation has been well studied. The aim of this work is to lay the groundwork for real time implementation of this computationally complex problem. The authors are with the Department of Electrical and Computer Engineering (MS 366), Rice University, Houston, Texas 77251-1892. This work was supported in part by Nokia Corporation, by the Texas Advanced Technology Program under grant #003604-049, and by NSF under grant NCR 9506681. This paper was presented in part at the 1997 8th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC), Helsinki, Finland.