Blind and semi-blind single user receiver techniques for asynchronous CDMA in multipath channels

Ghauri, Irfan;Slock, Dirk T M
GLOBECOM 1998, IEEE Global Telecommunications Conference ("The bridge to global integration"), November 8-12, 1998, Sydney, Australia

Prix d'excellence Hewlett-Packard

We consider multiple users in an asynchronous DS-CDMA system operating in a multipath environment. The received cyclostionary spread signal sampled at the chip rate is converted to a stationary vector signal,leading to a linear multichannel model. Linear receivers for multiple access interference (MAI) suppression are studied with emphasis on computationally simple algorithms. The desired user channel estimate is obtained by a new blind technique using the spreading sequence properties and second-order statistics. A blind MMSE-ZF receiver is subsequently obtained. Equivalence to the anchored MOE receiver is shown. Since the blind receiver relies on the inversion of the signal covariance matrix RY Y , a consistent estimate of which requires a large number of data points if a large number of users are concurrently active, a semi-blind alternative for the estimation of the interference canceling filter is presented. Iterative improvements of this estimate based upon exploitation of the finite-alphabet are investigated. Performances of different interference cancellation schemes are compared in terms of the output signal-to-interference-plus-noise ratio (SINR).

Systèmes de Communication
Eurecom Ref:
© 1998 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.