On Blind Channel Identification for Ds/cdma Communications

Blind channel identiication techniques based on second order statistics are investigated for multiuser systems employing Direct-Sequence/Code-Division Multiple-Access (DS/CDMA). The methods exploit knowledge of the spreading code of the user of interest via matched ltering, as well as properties of spreading codes. Two schemes are presented: one for deterministic short sequence DS/CDMA and a method appropriate for randomized long sequence DS/CDMA. The matched lter based techniques ooer reduced complexity vis a vis methods which operate on the received signal directly. In fact, it can be shown that as the number of matched lters increases, the proposed technique approaches a previously proposed method.