Pulse or digital communications – Repeaters – Testing
Patent
1993-02-03
1994-10-04
Gregory, Bernarr E.
Pulse or digital communications
Repeaters
Testing
380 34, 370 18, H04L 2730
Patent
active
053533020
ABSTRACT:
A signal despreader for use in a CDMA system processes samples of the received signal with filtered replicas of the code coefficient sequences associated with the system users. The symbols transmitted by each system user are recovered using a filtered replica of that user's associated code coefficient sequence. In the disclosed embodiment, the communications channel between each system user's transmitter and the base station is bandlimited. Accordingly, within each user's transmitter, filtering apparatus having a frequency characteristic is utilized to limit the frequency spectrum of each coded signal to a predetermined bandwidth equal to or less than that of the communications channel. Each filtered replica, pursuant to the present invention, reflects this frequency characteristic. In addition, the communications channel also has a frequency characteristic, and each filtered replica can reflect this characteristic as well.
REFERENCES:
patent: 3720789 (1973-03-01), Clark
patent: 4361891 (1982-11-01), Lobenstein et al.
patent: 4363338 (1982-12-01), McRae et al.
patent: 4611333 (1986-09-01), McCallister et al.
patent: 4885757 (1989-12-01), Provence
patent: 5136612 (1992-08-01), Bi
patent: 5170410 (1992-12-01), Gressier et al.
patent: 5173923 (1992-12-01), Crespo et al.
patent: 5175743 (1992-12-01), Crespo et al.
patent: 5175744 (1992-12-01), Crespo et al.
patent: 5177768 (1993-01-01), Crespo et al.
patent: 5181225 (1993-01-01), Neeser et al.
R. Lupas and S. Verdu, "Near-Far Resistance of Multiuser Detectors in Asynchronous Channels", IEEE Transactions on Communications, vol. 38, No. 4, Apr. 1990, pp. 496-507.
Q. Bi, "Performance Analysis of a CDMA Cellular System in the Multipath Fading Environment", The Third IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, Oct. 19-21, 1992, pp. 4.3.1-4.3.4.
AT&T Bell Laboratories
Gregory Bernarr E.
Padnes David R.
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