Method and apparatus for spreading and despreading data in a spread spectrum communication system
US6324206A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 23, 2000 |
| Grant date | Nov 27, 2001 |
| Priority date | — |
| Expiry date | Feb 23, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/2626
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A current mode of operation is provided to a Walsh spreader (203), and based on the current mode of operation, the Walsh spreader (203) either varies a Walsh code at a symbol rate, or holds the Walsh code constant. During multi-carrier transmission a first symbol within a data stream (210) is spread with a first Walsh code, while symbols immediately preceding and following the first symbol are spread by a another, differing Walsh code. The sequence of Walsh codes exiting the spreader (201) is further scrambled by a pair of Pseudo-Noise (PN) codes (224) that are held constant for three Walsh code periods during multi-carrier transmission, and are not held constant during direct-spread transmission.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.