Modulated backscatter wireless communication system having an extended range
US5873025A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 17, 1997 |
| Grant date | Feb 16, 1999 |
| Priority date | — |
| Expiry date | Jun 17, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S13/88
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A modulated backscatter communication system (e.g., an Electronic Shelf Label (ESL) system) includes a central node (e.g., a ceiling node) and one or more remote nodes (e.g., ESL tags). The central node transmits a downlink radio signal which is reflectively modulated at a remote node to produce a modulated reflected radio signal. At the remote node, a precise-frequency subcarrier signal is modulated with an uplink information signal to produce a modulated signal which is used to produce the modulated reflected radio signal. At the central node, the modulated reflected radio signal is received, detected and narrowband filtered to obtain the modulated subcarrier signal which is then demodulated to obtain the uplink information signal, with great immunity to close to carrier downlink radio noise and fluorescent light backscatter interference.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.