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US 2010/0060423 A1Published application
Radio frequency identification (RFID) reader with multiple receive channels
AssigneeIntermec Technologies Corporation
InventorVijay Pillai
Life of this patent
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Abstract
A radio-frequency identification (RFID) system includes an RFID tag, an RFID reader, and a controller. The RFID reader employs a plurality of phase-offset or phase-diverse channels to improve detection of data transmitted from the RFID tag to the RFID reader. A controller selects the channel that provides the best signal-to-noise ratio and decodes the data provided by the RFID tag using the selected channel.
Claims15
A radio frequency identification (RFID) reader for processing a signal received by a reader antenna, the RFID reader comprising:
- a first channel communicatively coupled to the reader antenna to process the received signal, wherein the first channel mixes the received signal with a LO signal provided at a first phase;
- a second channel communicatively coupled to the reader antenna to process the received signal, wherein the second channel mixes the received signal with a LO signal provided at a second phase offset from the first phase;
- a third channel communicatively coupled to the reader antenna to process the received signal, wherein the third channel mixes the received signal with a LO signal provided at a third phase offset from the first phase and the second phase;
- and
- a fourth channel communicatively coupled to the reader antenna to process the received received signal, wherein the fourth channel mixes the received signal with a LO signal provided at a fourth phase offset from the first phase, the second phase, and the third phase.
2 more elements
A method of processing RFID signals received by a reader, the method comprising:
- initializing a channel response by transmitting an initial transmission signal from a reader antenna;
- processing noisy reflections generated in response to the initial transmission signal using a plurality of phase-offset channels, wherein each channel is defined by a phase offset in a local oscillation (LO) signal mixed with the reflected signal;
- sampling and storing the processed reflections as noise values associated with each channel;
- interrogating an RFID tag by transmitting an interrogation signal from the reader antenna to an RFID tag;
- processing a signal received by the reader antenna in response to the interrogation signal using the plurality of phase-offset channels employed to process the response to the initial transmission signal, wherein the received signal includes a backscattered signal modulated with data provided by the RFID tag and a noise signal caused by reflections generated in response to the interrogation signal;
- measuring signal strength associated with each of the plurality of channels and employing the measured noise values calculated with respect to the initial transmission signal to determine signal-to-noise ratios (SNR) associated with each of the plurality of channels;
- and
- selecting a channel from the plurality of channels providing the highest SNR and decoding information provided by the RFID tag based on the selected channel.
5 more elements
A radio-frequency identification (RFID) system comprising:
- an RFID tag having an antenna for receiving and reflecting transmitted signals;
- an RFID reader having at least one antenna for receiving and transmitting signals and a plurality of phase-diverse channels communicatively coupled to the receiving antenna for processing received signals, wherein each phase-diverse channel employs a mixer for mixing a received signal with a local oscillator (LO) signal phase-shifted with respect to each of the plurality of channels;
- and
- a controller communicatively coupled to the RFID reader for receiving the signals processed by each of the plurality of phase-diverse channels, wherein the controller decodes data provided by the RFID tag based on the processed signals provided by the plurality of phase-diverse channels.
1 more element
Dependencies are inferred from the claim text.