US 8,427,279 B2 · Multi-protocol RFID system using bit-lock or step-lock synchronization

Abstract

A multi-protocol RFID interrogating system employs a synchronization technique (step-lock) for a backscatter RFID system that allows simultaneous operation of closely spaced interrogators. The multi-protocol RFID interrogating system can communicate with backscatter transponders having different output protocols and with active transponders including: Title 21 compliant RFID backscatter transponders; IT2000 RFID backscatter transponders that provide an extended mode capability beyond Title 21; EGO™ RFID backscatter transponders, SEGO™ RFID backscatter transponders; ATA, ISO, ANSI AAR compliant RFID backscatter transponders; and IAG compliant active technology transponders. The system implements a step-lock operation, whereby adjacent interrogators are synchronized to ensure that all downlinks operate within the same time frame and all uplinks operate within the same time frame, to eliminate downlink on uplink interference.

Claims30

Dependent claims

An interrogator system to read active RFID transponders and backscatter RFID transponders comprising

at least two transceivers,
each transceiver covering a respective capture zone, the two capture zones being in proximity to each other, wherein said transceivers are adapted to use time division multiplexing to read the active RFID transponders in a first capture zone during a first time period, to read the active RFID transponders in a second capture zone during second time period and to simultaneously read the backscatter RFID transponders in both capture zones during a third time period, wherein a synchronization signal is shared between said transceivers, and wherein the read of the backscatter RFID transponders in the third time period by each transceiver comprises a downlink transmission, the downlink transmission comprising plural bits, and wherein each bit of the backscatter downlink transmission of each transceiver occurs at substantially the same time.

An interrogation system for communicating with a plurality of transponders having different communication protocols, the interrogation system comprising

a plurality of interrogators and
a synchronization signal,
each of the interrogators comprising
a transmitter and
a receiver
the transmitters being arranged for transmitting downlink signals in accordance with different communication protocols over a downlink communications link to the transponders,
the receivers being arranged for receiving respective uplink signals over an uplink communications signal link from the transponders,
the synchronization signal being arranged for synchronizing the downlink signals for each of the plurality of interrogators, each of the interrogators operating in response to the synchronization signal to simultaneously transmit the downlink signals to the transponders to enable the transponders to provide their respective uplink signals after the transmission of the downlink signals, thereby enabling communication between respective ones of the interrogators and transponders without interference between the uplink signals from the transponders and the downlink signals from the interrogators,
wherein the system establishes a tag communication signal sequence, said signal sequence comprising first and second said sequence portions, said signal sequence being arranged to enable said system to read at least one active RFID transponder in a first capture zone during said first sequence portion, and to read at least one active RFID transponder in a second capture zone during said second sequence portion.

6 more elements

Dependencies are inferred from the claim text.

Multi-protocol RFID system using bit-lock or step-lock synchronization

Life of this patent

Multi-protocol RFID system using bit-lock or step-lock synchronization

Life of this patent

Abstract

Claims30