Precoding of signature sequences for cdma systems
CA 2100847 C · Owner: American Telephone And Telegraph Company · Inventors: Weerackody, Vijitha
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A technique for reducing multiple access interference (MAI) experienced by receivers of transmissions from a transmitter e.g. a base station, in a, direct-sequence code division multiple access communication system e.g. a cellular, radio system, is disclosed. The technique provides for the precoding of user signature sequences for use in spreading information signals to be transmitted. The use of precoded signature sequences significantly reduces the average level of MAI experienced by the receivers. Despreading of received signals by receivers may be accomplished with the original (i.e. non-precoded) signature sequences. Thus no, changes to receivers are required. The technique includes a …
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed July 19, 1993 and granted December 23, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended July 19, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by July 19, 2015.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
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Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.