CDMA subtractive demodulation
US5151919A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 17, 1990 |
| Grant date | Sep 29, 1992 |
| Priority date | — |
| Expiry date | Dec 17, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B2201/70703
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Substractive CDMA demodulation optimally decodes a coded information signal embedded in may other overlapping signals making up a received, composite signal. A radio receiver correlates a unique code corresponding to the desired signal to be decoded with the composite signal. Moreover, after each information signal is successfully decoded, it is recoded and removed from the composite signal. As a result, subsequent correlations are performed with greater accuracy. Substractive CDMA demodulation is enhanced by decoding the composite signal in the order of strongest to weakest signal strength. Interference caused by the presence of the strongest information signal and the composite signal during the decoding of weaker signals is removed. The individual information signals are assigned a unique block error correction code with is correlated with the composite signal using Fast Walsh transforms. Correlated signals are recoded using inverted Fast Walsh transforms and removed from the composite signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.