US 9,805,235 B2 · Systems and methods for synchronizing a plurality of RFID interrogators in a theatre of operation

Abstract

RFID tags are used for many purpose including tracking. RFID interrogators are used to retrieve information from tags. In many applications, a plurality of RFID interrogators are required. Synchronization between interrogators in the same theatre of operation is critical to ensure that their broadcasts do not interfere with each other. In fixed RFID interrogator applications, RFID interrogators can be wired together allowing a channel to synchronize the transmissions of the RFID interrogators. Methods described herein can ensure that synchronization is maintained in the event of the failure of a synchronizing master. Furthermore, additional methods for synchronizing RFID interrogators in wireless applications are described allowing synchronization in the absence of wired connections between interrogators.

Claims20

Dependent claims

A radio frequency identification (RFID) interrogation system, comprising:

multiple RFID interrogators, wherein each of the multiple RFID interrogators is configured to transmit data to surrounding RFID tags, and wherein the multiple RFID interrogators includes a first RFID interrogator, the first RFID interrogator is configured to:
transmit a portion of data to nearby RFID tags in a first half of a first frame;
wait a time period for a second half of the first frame to start;
upon the start of the second half of the first frame, detect any interference from another RFID interrogator among the multiple RFID interrogators;
and
if an interference is detected from another RFID interrogator among the multiple RFID interrogators, determine if data is expected from a nearby RFID tag, and if no data is expected, adjust a timing of a start of a second frame to coincide with the start of a frame of the another RFID interrogator;
and
if data is expected, select a random number of frames to wait to receive the expected data.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application

15/483,908Filed 10 Apr 2017 · continuation

Priority

21 Jun 2006

Published

US 2017/0235982 A117 Aug 2017

Granted

31 Oct 2017

Term ends

Not estimatedThe source records don’t support an estimate.

Classification20 codes

G06K 7/10475
The interrogation device being adapted for miscellaneous applications: arrangements to facilitate interaction with further interrogation devices,…
G06K 7/0008
Methods or arrangements for sensing record carriers, e.g. for reading patterns: general problems related to the reading of electronic memory…
G06K 7/10029
Resolving collision on the communication channels between simultaneously or concurrently interrogated record carriers.: the collision being…
G06K 7/10039
The collision being resolved in the time domain, e.g. using binary tree search or RFID responses allocated to a random time slot: interrogator…

Family

Application60/805,423Us provisional application · filed 21 Jun 2006

Application11/766,749Parent of this continuation · filed 21 Jun 2007

Application14/225,359Parent of this continuation · filed 25 Mar 2014

US 8,680,973 B2Parent of this continuation · filed 25 Mar 2014

Application15/007,079Parent of this continuation · filed 26 Jan 2016

US 9,247,634 B2Parent of this continuation · filed 26 Jan 2016

US 2017/0235982 A1Pre-grant publication · published 17 Aug 2017

US 9,626,619 B2Parent of this continuation

US 2008/0018489 A1Published application

US 2015/0022323 A1Published application

US 2016/0162776 A1Published application

US 9,805,235 B2This patent

From the US filing history. Foreign family members aren’t listed.

Systems and methods for synchronizing a plurality of RFID interrogators in a theatre of operation

Life of this patent

Systems and methods for synchronizing a plurality of RFID interrogators in a theatre of operation

Life of this patent

Abstract

Claims20