DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Information Disclosure Statement
The information disclosure statements (IDS) submitted on 03/29/2024, 12/18/2024, and 02/26/2025 are in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statements are being considered by the examiner.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claims 1-7 and 10-15 are rejected under 35 U.S.C. 103 as being unpatentable over Lin et al. US 2008 0136645 A1 (hereinafter “Lin”) as modified by Lee et al. US 20110136445 A1 (hereinafter “Lee”) and further in view of Ko et al. WO 2021107583 A1 (hereinafter “Ko”).
Regarding Claim 1, Lin teaches a radio-frequency identification (RFID) tag reader (Page 2, Paragraph 29, Fig. 4, RFID reader 400) comprising:
a signal generator to generate an interrogation signal (Pages 1-2, Paragraph 13, backend module; Paragraph 29, Fig. 4, backend module 450 includes control block 401, an RF oscillator 402, a power splitter 403, a PA 404, and a demodulator 414);
an antenna to transmit the interrogation signal to an RFID tag and to receive a reply to the interrogation signal from the RFID tag (Page 2, Paragraphs 29-31, Fig. 4, antenna 406, tag);
a circulator having a first port operably coupled to the signal generator to receive the interrogation signal, a second port operably coupled to the antenna to couple the interrogation signal to the antenna and to receive the reply from the antenna, and a third port to emit the reply to the interrogation signal (Page 2, Paragraphs 29-31, circulator 405, first port P1, second port P2, third port P3, antenna 406);
a self-interference cancellation circuit, operably coupled to the signal generator and the third port of the circulator (Page 2, Paragraph 31, echo cancellation circuit 407), to cancel interference caused by (i) leakage of the interrogation signal from the first port of the circulator to the third port of the circulator and/or (ii) crosstalk between antenna elements in the antenna by amplifying a portion of the interrogation signal by a complex gain and adding the portion of the interrogation signal to the reply to the interrogation signal (Pages 2-3, Paragraphs 31-38, leak of the interrogation signal, in-band interference, echo cancellation circuit); and
a processor, operably coupled to the self-interference cancellation circuit, to calibrate a complex gain of the self-interference circuit (Page 3, Paragraph 37, digital signal processor [DSP]).
Lin fails to fully teach:a self-interference cancellation circuit
However, Lee further teaches
a self-interference cancellation circuit (Lee, Page 3, Paragraph 57, digital signal processor 321, Processor 311; Fig. 4, DAC 421 to Amplitude/Phase shifter 423, DAC 425 to Amplitude/Phase Shifter 427)
Although Lin addresses the remaining limitations of claim 1, Lee demonstrates the following limitations of a radio-frequency identification (RFID) tag reader (Lee, Pages 3-4, Paragraphs 51-79, Fig. 3, RFID reader 300) comprising:
a signal generator to generate an interrogation signal (Lee, Page 3, Paragraphs 52-54, Transmitting unit 313);
an antenna to transmit the interrogation signal to an RFID tag and to receive a reply to the interrogation signal from the RFID tag (Lee, Page 3, Paragraph 52, Antenna 319, 341);
Lee and Lin are considered to be analogous to the claimed invention because they are in the same field of transmission systems of RFID readers. Therefore, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have modified Lin to incorporate the teachings of Lee for a self-interference cancellation circuit. Do so would allow further control over calibrating the complex gain.
Lin in view of Lee fails to fully teach:
a processor, operably coupled to the self-interference cancellation circuit, to calibrate a complex gain of the self-interference circuit.
However, Ko teaches: a processor, operably coupled to the self-interference cancellation circuit (Ko, Page 11, Fig. 2, Page 20, Paragraphs 24-25; RFID reader, leakage signal remove unit) to calibrate a complex gain of the self-interference circuit (Ko, Page 12, Figs. 3-5, controller 300 of a transceiver for an RFID reader, rotator 340, integrator 320, rotator 340; Pages 21-29, Paragraphs 27-52, leakage signal removing unit, gain controller 310).
Although Lin in view of Lee addresses the remaining limitations of claim 1, Ko demonstrates the following limitations of a radio-frequency identification (RFID) tag reader (Ko, Page 12, Fig. 2, RFID reader) comprising:
a signal generator to generate an interrogation signal (Ko, Page 20, Paragraph 24, transmitting end 230, processor 200);
an antenna to transmit the interrogation signal to an RFID tag and to receive a reply to the interrogation signal from the RFID tag (Page 20, Paragraph 24, antenna 270);
Ko, Lee and Lin are considered to be analogous to the claimed invention because they are in the same field of transmission systems of RFID readers. Therefore, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have modified Lin in view of Lee to incorporate the teachings of Ko for a processor, operably coupled to the self-interference cancellation circuit, to calibrate a complex gain of the self-interference circuit. Doing so would enable streamlined measurement sampling and subsequent conversions for complex gain computations.
Regarding Claim 2, Lin as modified by Lee and further in view of Ko teaches the RFID tag reader of claim 1, wherein the processor is configured to calibrate the complex gain by:
performing a measurement y1(n) of self-interference cancellation by the self-interference cancellation circuit at a first complex gain setting Gx(n) (Lin, Page 3, Paragraphs 33-38, gain calculator and Lin, Pages 2-3, Paragraph 30, carrier signal Vm; Paragraph 34-35, equation 1, Vm*, complex conjugate of received carrier signal Vm ;);
performing a measurement y2(n) of self-interference cancellation by the self-interference cancellation circuit at a second complex gain setting Gx(n)G∆ (Lin, Page 3, Paragraphs 33-38 and Lin, Pages 2-3, Paragraph 31, backscatter signal Vb, leakage carrier signal Vm’, combination of Vb and Vm’ is denoted as received signal Vf; Paragraph 34-35, equation 1, Vf*, complex conjugate of received signal Vf ;); and
adjusting the complex gain based on the measurement y1(n), the first complex gain setting Gx(n), the measurement y2(n), and the second complex gain setting Gx(n)G∆ (Lin, Page 3, Paragraphs 33-38 and Lin, Page 3, Paragraph 33, output of cancellation circuit Vd, calculated by complex gain adjustment, Vm, Vf; Paragraph 34-36, gain calculator 409, equation 1, complex gain value a, calculated via algorithm, equations 2-5, includes iteration index k; Paragraph 37-38, DSP, adaptive algorithm, complex gain value a is always optimal).
Regarding Claim 3, Lin view of Ko teaches the RFID tag reader of claim 2, wherein the processor comprises:
an integrator to perform the measurement y1(n) and the measurement y2(n) (Lin, Pages 3, Paragraph 33, echo cancellation circuit 407, gain calculator 409; Paragraph 37, DSP, control block 401; Ko, Pages 22-23, Paragraphs 34-40, digital stage 2500 includes a gain controller 310, and integrator 320, a controller 330, and a rotator 340);
at least one COordinate Rotation Digital Computer (CORDIC), operably coupled to the integrator, to compute a magnitude and a phase of y2(n)G∆ - y1(n) and to compute a magnitude and a phase of y2(n) - y1(n) (Lin, Page 3, Paragraphs 33-36; Ko, Pages 26-28, Paragraph 45-49, rotator 340, CORDIC algorithm).
Regarding Claim 4, Lin as modified by Lee and further in view of Ko teaches the RFID tag reader of claim 3, wherein the integrator is configured to perform the measurement y1(n) and the measurement y2(n) by acquiring a number of cycles equal to an integer multiple of a number of cycles of carrier frequency of the interrogation signal (Lin, Page 3, Paragraphs 33-38, adaptive algorithm; Lee, Page 4, Paragraph 77, iteration count).
Regarding Claim 5, Lin as modified by Lee and further in view of Ko teaches the RFID tag reader of claim 4, wherein the number of cycles is equal to an integer multiple of a number of cycles of a carrier frequency of a channel adjacent to a channel of the interrogation signal (Lin, Page 3, Paragraphs 38; Lee, Page 5, Paragraphs 94-101, Fig. 5, Steps 121-127 and Steps 135-137).
Regarding Claim 6, Lin in view of Ko teaches the RFID tag reader of claim 1, wherein the processor is configured to calibrate the self-interference cancellation circuit at a beginning of each transmission by the antenna to the RFID tag (Lin, Page 3, Paragraphs 37-38; Ko, Pages 21-29, Paragraphs 27-52, leakage signal removing unit, gain controller 310).
Regarding Claim 7, Lin as modified by Lee and further in view of Ko teaches the RFID tag reader of claim 1, wherein the self-interference circuit comprises:
an adjustable phase compensator to provide a phase component of the complex gain (Lin, Page 3, Paragraph 33, gain adjustment circuit 408);
a first digital-to-analog converter (DAC), operably coupled to the adjustable phase compensator and the processor, to adjust the phase component of the complex gain based on feedback from the processor (Lin, Page 3, Paragraph 37, DSP; Lee, Fig. 4, DAC 421, DAC 425; Ko, Page 23, Paragraph 36, DAC 2110, gain controller 310);
an adjustable gain compensator to provide a gain component of the complex gain; and
a second DAC, operably coupled to the adjustable gain compensator and the processor, to adjust the gain component of the complex gain based on feedback from the processor (Lin, Page 3, Paragraphs 33-38, gain adjustment; Lee, Fig. 4, DAC 421 to Amplitude/Phase shifter 423, DAC 425 to Amplitude/Phase Shifter 427; Ko, Page 23, Paragraph 36, gain controller 310).
Regarding Claim 10, Lin as modified by Lee and further in view of Ko teaches a method of interrogating a radio-frequency identification (RFID) tag with an RFID tag reader comprising a self-interference cancellation circuit, the method comprising:
generating a continuous wave (CW) signal with the RFID tag reader (Lin, Page 2, Paragraph 13, RFID reader, RFID tag; Lee, Page 3, Paragraphs 44-50, Fig. 2, RFID reader 200, tag 250, signal 201);
calibrating a complex cancellation gain of the self-interference cancellation circuit based on iterative measurements of self-interference cancellation of the CW signal at a first receiver gain level (Lin, Page 2, Paragraphs 13-14, echo cancellation circuit)
after calibrating the complex cancellation gain, transmitting an interrogation signal to the RFID tag (Lee, Page 3, Paragraph 49, signal 203);
receiving a reply to the interrogation signal from the RFID tag at a second receiver gain level higher than the first receiver gain level (Lee, Page 3, Paragraph 47, receives TX information from tag 250); and
cancelling self-interference from the reply with the self-interference cancellation circuit (Lin, Page 3, Paragraphs 33-38, echo cancellation circuit 407; Lee, Page 5, Fig. 5, Paragraphs 89-103; Ko, Page 12, Figs. 3-5, controller 300 of a transceiver for an RFID reader, rotator 340, integrator 320, rotator 340; Pages 21-29, Paragraphs 27-52, leakage signal removing unit, gain controller 310).
Regarding Claim 11, Lin teaches the method of claim 10, wherein calibrating the complex cancellation gain comprises:
performing a measurement y1(n) of self-interference cancellation by the self-interference cancellation circuit at a first complex gain setting Gx(n) of the self-interference cancellation circuit; (Lin, Pages 2-3, Paragraph 30, carrier signal Vm; Paragraph 34-35, equation 1, Vm*, complex conjugate of received carrier signal Vm);
performing a measurement y2(n) of self-interference cancellation by the self-interference cancellation circuit at a second complex gain setting Gx(n)G∆ of the self-interference cancellation circuit; (Lin, Pages 2-3, Paragraph 31, backscatter signal Vb, leakage carrier signal Vm’, combination of Vb and Vm’ is denoted as received signal Vf; Paragraph 34-35, equation 1, Vf*, complex conjugate of received signal Vf ) and
adjusting the complex cancellation gain of the self-interference cancellation circuit based on the measurement y1(n), the first complex gain setting Gx(n), the measurement y2(n), and the second complex gain setting Gx(n)G∆. (Lin, Pages 3, Paragraph 33-38, echo cancellation circuit 407, gain calculator 409 and Lin, Page 3, Paragraph 33, output of cancellation circuit Vd, calculated by complex gain adjustment, Vm, Vf; Paragraph 34-36, gain calculator 409, equation 1, complex gain value a, calculated via algorithm, equations 2-5, includes iteration index k; Paragraph 37-38, DSP, adaptive algorithm, complex gain value a is always optimal)
Regarding Claim 12, Lin as modified by Lee and further in view of Ko teaches the method of claim 11, wherein adjusting the complex cancellation gain comprises computing a magnitude and a phase of y2(n)G∆ - y1(n); and computing a magnitude and a phase of y2(n) - y1(n) (Lin, Pages 3, Paragraph 33-37, echo cancellation circuit 407, gain calculator 409; Lee, Page 5, Paragraphs 89-103; Ko, Pages 22-23, Paragraphs 34-40, digital stage 2500; Pages 26-28, Paragraphs 45-49, rotator, CORDIC algorithm).
Regarding Claim 13, Lin in view of Lee teaches the method of claim 11, wherein performing the measurement y1(n) comprises acquiring a number of cycles equal to an integer multiple of a number of cycles of a carrier frequency of the interrogation signal (Lin. Page 3, Paragraphs 33-38, adaptive algorithm; Lee, Page 4, Paragraph 77, iteration count).
Regarding Claim 14, Lin in view of Lee teaches the method of claim 13, wherein the number of cycles is equal to an integer multiple of a number of cycles of a carrier frequency of a channel adjacent to a channel of the interrogation signal (Lin, Page 3, Paragraphs 33-38, adaptive algorithm; Lee, Page 4, Paragraph 77, iteration count; Page 5, Paragraphs 94-101, Fig. 5, Steps 121-127 and 135-137).
Regarding Claim 15, Lin in view of Lee teaches the method of claim 10, wherein calibrating the complex cancellation gain comprises: adjusting a phase component of the complex cancellation gain with an adjustable phase compensator; and (Lin, Page 3, Paragraph 33, output of cancellation circuit Vd, calculated by complex gain adjustment, Vm, Vf) ;
adjusting a gain component of the complex cancellation gain with an adjustable gain compensator (Lin, Page 3, Paragraphs 33-38, Lee, Fig. 4, DAC 421, 425).
Regarding Claim 17, Lin as modified by Lee and further in view of Ko teaches a method of calibrating a radio-frequency identification (RFID) tag reader, the method comprising:
performing a first measurement of self-interference cancellation by a self-interference cancellation circuit of the RFID tag reader at a first complex gain of the self-interference cancellation circuit (Lin, Page 3, Paragraphs 33-38, gain calculator);
performing a second measurement of self-interference cancellation by a self-interference cancellation circuit of the RFID tag reader at a second complex gain of the self-interference cancellation circuit different than the first complex gain (Lin, Page 3, Paragraphs 33-38);
adjusting a complex gain of the self-interference cancellation circuit based on the first measurement, the first complex gain, the second measurement, and the second complex gain (Lin, Pages 3, Paragraph 33-38, echo cancellation circuit 407, gain calculator 409; Lee, Page 5, Fig. 5, Paragraphs 89-103; Ko, Pages 21-29, Paragraphs 27-52, leakage signal removing unit).
Regarding Claim 18, Lin as modified by Lee and further in view of Ko teaches the method of claim 17, wherein performing the first measurement comprises selecting the first complex gain based on a dynamic range of an analog-to-digital converter (ADC) of the RFID tag reader (Lin, Page 2, Paragraph 31, demodulator 414, DSP; Lee, Page 4, Paragraphs 73-76, ADC).
Regarding Claim 19, Lin as modified by Lee and further in view of Ko teaches the method of claim 17, wherein the second complex gain is greater than the first complex gain (Lin, Page 2, Paragraph 31; Lee, Page 6, Paragraphs 97-98, signal level).
Regarding Claim 20, Lin as modified by Lee and further in view of Ko teaches the method of claim 17, further comprising, after adjusting the complex gain:
interrogating an RFID tag with the RFID tag reader (Lin, Page 2, Paragraph 31; Lee, Page 3, Paragraphs 44-50).
Regarding Claim 21, Lin as modified by Lee and further in view of Ko teaches the method of claim 20, wherein interrogating the RFID tag comprises:
transmitting, by the RFID tag reader, a continuous-wave (CW) signal to the RFID tag (Lin, Pages 2-3, Paragraphs 29-30; Lee, Page 3, Paragraph 49, signal 201);
while transmitting the CW signal, re-calibrating the complex gain of the self-interference cancellation circuit (Lee, Page 3, Paragraph 49, signal 203);
after re-calibrating the complex gain, transmitting, by the RFID tag reader, a signal to RFID tag;
receiving, by the RFID tag reader, a reply from the RFID tag to the signal from the RFID tag reader (Lin, Page 2, Paragraph 31; Lee, Page 3, Paragraph 47); and
cancelling self-interference from the reply with the self-interference cancellation circuit (Lin, Pages 2-3, Paragraphs 32-36; Lee, Page 5, Paragraphs 89-103; Ko, Pages 22-23, Paragraphs 34-40).
Regarding Claim 22, Lin as modified by Lee teaches the method of claim 21, wherein re-calibrating the complex gain of the self-interference cancellation circuit comprises:
performing a pair of measurements of the self-interference cancellation by the self-interference cancellation circuit; and
adjusting the complex gain based on the pair of measurements (Lin, Pages 2-3, Paragraphs 32-36; Lee, Page 5, Paragraphs 89-103).
Regarding Claim 23, Lin teaches the method of claim 22, wherein performing the pair of measurements comprises suppressing interference from channels adjacent to a channel of the signal transmitted by the RFID tag reader to the RFID tag (Lin, Page 3, Paragraph 38).
Claims 8-9 and 16 are rejected under 35 U.S.C. 103 as being unpatentable over Lin as modified by Lee in view of Ko and further in view of Bellantoni et al. US 2005 0231367 A1 (hereinafter “Bellantoni”).
Regarding Claim 8, Lin as modified by Lee and further in view of Ko teaches the RFID tag reader of claim 1, wherein:
the RFID tag reader receives interrogation signals from other RFID tag readers and replies to the interrogation signals from the other RFID tag readers (Lin, Page 3, Paragraph 38, adaptive algorithm, other RFID readers).
Lin as modified by Lee and further in view of Ko fails to fully teach:
the RFID tag reader is configured to be switched between an interrogator mode
and a listener mode
However, Bellantoni further teaches the RFID tag reader of claim 1, wherein:
the RFID tag reader is configured to be switched between an interrogator mode in which the RFID tag reader transmits interrogation signals and receives replies to the interrogation signals and a listener mode in which the RFID tag reader receives interrogation signals from other RFID tag readers and replies to the interrogation signals from the other RFID tag readers (Bellantoni, Page 8, Paragraphs 85-86, Fig. 15A, TRANSMIT mode, Fig. 15B, LISTEN mode).
Bellantoni, Ko, Lee and Lin are considered to be analogous to the claimed invention because they are in the same field of transmission systems of RFID readers. Therefore, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have modified Lin as modified by Lee in view of Ko to incorporate the teachings of Bellantoni in which the RFID tag reader is configured to be switched between an interrogator mode in which the RFID tag reader transmits interrogation signals and receives replies to the interrogation signals and a listener mode in which the RFID tag reader receives interrogation signals from other RFID tag readers and replies to the interrogation signals from the other RFID tag readers. Doing so would optimize the use of system resources by enabling the use of multiple operational modes.
Regarding Claim 9, Lin as modified by Bellantoni teaches the RFID tag reader of claim 8, wherein the self-interference cancellation circuit is disabled when the RFID tag reader is in listener mode (Lin, Pages 2-3, Paragraph 32, demodulator 414 capable of processing signal directly; Paragraph 38, adaptive algorithm; Bellantoni, Page 2, Paragraph 13, Listen only mode).
Regarding Claim 16, Lin as modified by Bellantoni teaches the method of claim 10, wherein the RFID tag reader is configured to be switched between an interrogator mode in which the RFID tag reader transmits interrogation signals and receives replies to the interrogation signals and a listener mode in which the RFID tag reader receives interrogation signals from other RFID tag readers and replies to the interrogation signals from the other RFID tag readers (Lin, Page 3, Paragraph 38, adaptive algorithm, other RFID readers; Bellantoni, Page 8, Paragraphs 85-86, Fig. 15A, TRANSMIT mode, Fig. 15B, LISTEN mode), and further comprising:
disabling the self-interference cancellation circuit when the RFID tag reader is in listener mode (Lin, Pages 2-3, Paragraph 32, demodulator 414 capable of processing signal directly; Paragraph 38, adaptive algorithm; Bellantoni, Page 2, Paragraph 13, Listen only mode).
Conclusion
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/GABRIELLE N DAI/Examiner, Art Unit 2681
/AKWASI M SARPONG/SPE, Art Unit 2681 1/09/2025