Methods and apparatus for a spread spectrum modulated backscatter electronic shelf label system
First Claim
1. An electronic price label (ESL) system comprising:
- an ESL receiving a message transmitted from a communications base station (CBS), the ESL including a transmitter having a generator for producing a pseudo-random code sequence, the transmitter transmitting a response to the message by reflectively modulating a continuous wave (CW) signal with the pseudo-random code sequence so as to impose the pseudo-random code sequence on the continuous wave signal; and
the CBS receiving and correlating the reflectively modulated CW signal.
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Accused Products
Abstract
Techniques for an electronic shelf label (ESL) system which uses a digital modulation technique for a modulated backscatter uplink from an ESL to a communication base station (CBS) which utilizes pseudo-random sequences instead of a single continuous wave frequency. The CBS transmits a message to an ESL using a Manchester coded amplitude modulated carrier. After receiving the message, the ESL responds by reflectively modulating a continuous wave (CW) signal with a pseudo-random code sequence. Multiple pseudo-random code sequences may be chosen, with each code sequence corresponding to a particular response. The code sequence is modulated onto a kHz carrier which is used to reflectively modulate the CW signal received from the CBS. The CBS then receives the reflectively modulated signal and correlates the received signal to determine message transmitted.
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Citations
33 Claims
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1. An electronic price label (ESL) system comprising:
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an ESL receiving a message transmitted from a communications base station (CBS), the ESL including a transmitter having a generator for producing a pseudo-random code sequence, the transmitter transmitting a response to the message by reflectively modulating a continuous wave (CW) signal with the pseudo-random code sequence so as to impose the pseudo-random code sequence on the continuous wave signal; and the CBS receiving and correlating the reflectively modulated CW signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. An electronic shelf label (ESL) communication method comprising the steps of:
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transmitting a message to an ESL from a communications base station (CBS); generating a pseudo-random code sequence at the ESL; transmitting a response by the ESL to the message by reflectively modulating a continuous wave (CW) signal with the generated pseudo-random code sequence so as to impose the pseudo-random code sequence onto the continuous wave signal; and receiving and correlating the reflectively modulated CW signal by the CBS. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23)
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24. An electronic price label (ESL) comprising:
an ESL receiving a message transmitted from a communications base station (CBS), the ESL including a transmitter having a generator for producing a pseudo-random code sequence, the transmitter transmitting a response to the message by reflectively modulating a continuous. wave (CW) signal with the pseudo-random code sequence so as to impose the pseudo-random code sequence onto the continuous wave signal. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32, 33)
Specification