Method for simultaneous detection of a plurality of RFID tags using multiuser detection
US9769547B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 12, 2009 |
| Grant date | Sep 19, 2017 |
| Priority date | — |
| Expiry date | Jun 25, 2036 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04Q2209/753
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A method and apparatus are disclosed that apply multiuser detection (MUD) analysis to an aggregated RF response from a plurality of simultaneously queried RFID tags, so as to distinguish the individual tag responses. The claimed method thereby significantly reduces RFID detection latency when multiple tags are simultaneously queried. Some embodiments transmit carrier waves at more than one frequency, such as a plurality of equally-spaced frequencies, so as to enhance the MUD analysis by incorporating a multi-frequency dimension. Other embodiments incorporate additional spatial dimensions by deploying multiple RF detection antennae at separated locations. The number of colliding tag responses must be estimated before MUD analysis can be applied. In some embodiments other signal parameters must be estimated, such as signal bias and an impulse function for each responding tag that characterizes alterations of the RF signal while in transit due to propagation distance, passage through intervening objects, and reflections.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.