Semiblind channel estimation for space-time coded WCDMA

Abstract

A new semi-blind channel estimation technique is proposed for space-time coded wideband CDMA systems using aperiodic and possibly multirate spreading codes. Exploiting the subspace structure of the WCDMA signaling and the orthogonality of the spacetime code, the proposed algorithm provides the least squares channel estimate in closed form. Using a decorrelating matched filter, the proposed method projects the received signal into subspaces from which channel parameters and data symbols can be estimated jointly. A new blind identifiability condition is established. The mean square error of the estimated channel is compared with the Cramér-Rao bound, and bit error rate (BER) is assessed through Monte Carlo simulation.

Channel estimation for chip‐level Alamouti coded multi‐rate CDMA: blind subspace algorithms and performance analysis

“…Simple linear receiver structures for multi-rate STBC-CDMA systems based on the decorrelating and minimum variance distortionless response principles were presented in Reference [7]. Like all coherent detection methods, they assume that an estimate of the channel vector is available.…”

“…A blind subspace-based channel estimation algorithm is derived in Section 3. Section 4 provides the † We note that the antenna ambiguity problem can also be addressed with the use of pilot symbols (as in Reference [7]) at the expense of spectral efficiency loss due to the transmission of the pilots.…”