Semi-blind spatio-temporal channel estimation for CDMA systems

In this paper two semi-blind channel estimation techniques are proposed for synchronous DS-CDMA signals transmitted over a multiuser multipath channel. An initial channel estimate is obtained, then statistical techniques are used to enhance the quality of this estimate. In the first technique the channel parameters are estimated first and then used to construct the signal subspace. This information is then used to form an improved channel estimate. The second technique is similar, but uses an adaptive structure to obtain the signal subspace directly. The performance of the techniques is evaluated and compared through analysis and simulation studies