Direct sequence/code‐division multiple‐access adaptive interference canceller on differential detection for fast fading channel
Shousei Yoshida, A. Ushirokawa, Shuzo Yanagi, Y. Furuya · Electronics and Communications in Japan (Part I Communications) · 1996
Abstract This paper proposes the differential detection type direct sequence/code‐division multiple‐access (DS/ CDMA) adaptive interference canceller (AIC) that can track the fast fading. The proposed AIC is composed of the fractionally chip‐spaced code‐orthogonalizing filter (COF) with tap length corresponding to several bit periods and the differential detector. The COF makes adaptively the tap weight orthogonal to all spreading codes of other users as a despreading code of the desired user so that the interferences from other users are cancelled and the signal component of the desired user is extracted. The differential detector compensates the carrier phase variation due to fading in the desired user's signal at the COF output. By such a structure, the tracking performance of AIC to the channel variation can be improved to the limit of the tracking performance of the differential detector. This paper evaluates the basic ability of the proposed AIC in the fast‐fading channel. The AIC is especially expected to be utilized in the DS/CDMA mobile communications since the receiver is of the single‐user type, where no information concerning other users is needed.