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 statement (IDS) submitted on 12/22/2023 is in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statement is being considered by the examiner.
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention.
Claims 1, 5, and 7-13 are rejected under 35 U.S.C. 102(a)(2) as being anticipated by Taher et al., U.S. Patent Application Publication No. 2018/0159637 (hereinafter Taher1).
Regarding Claim 1, Taher1 teaches a method for synchronizing time alignment in a multi-channel radio frequency receiving system (“systems, storage media, and methods for calibrating a multiple input multiple output (MIMO) radio system” – See [¶0004], including “a method whereby a single calibration signal is used by a MIMO radio system to perform each of time synchronization, phase synchronization, and frequency response correction for each of the multiple receivers” – See [¶0005] and Fig. 10), the method comprising:
injecting an amplitude modulated or phase modulated reference signal into each channel in the multi-channel receiver at a location associated with each antenna input (“a pilot waveform signal may be generated at the cal signal generator 120” – See [¶0066] and Fig. 2, whereby a “10 MHz common reference signal 108 ensures that the digital-to- analog converter (DAC) of the signal generator 120 and the receivers' digitizer analog-to-digital converters (ADCs) 102-106 are locked with respect to the reference and to each other” – See [¶0033] and a “radio frequency (RF) up-conversion is then performed to prepare the signal for transmission. The signal is then put through a 1:N splitter (1:3 splitter in the particular embodiment shown in FIG. 3), and one of the split signals is transmitted to one of the receivers 102-106” – See [¶0067]);
detecting a position of the reference signal within a time sample window for each channel after analog to digital conversion (“a processor at the receiver finds the Pilot Start, which comprises a coarse timing of the signal” – See [¶0069] and Fig. 4 at step 312, after “RF down conversion is performed on the received signal, and analog-to-digital conversion is performed at 310 to prepare the signal for processing” – See [¶0068], whereby the time sample window may be determined based on cross-correlation with the local Reference Pilot whereby a “sharp peak will be observed in the correlation of the received ZC sequence with the local copy of the ZC sequence only when the two sequences are properly lined up (e.g., properly lined up in time and/or phase)” – See [¶0037]; furthermore, “the time domain equalizer may be advantageous when the inter-symbol interference (ISI) caused by the non-flat frequency response of the imperfect receiver hardware is several data symbols long,” – See [¶0073] i.e., the time sample window for synchronization may be at least several baseband symbols long; see also Fig. 5 showing several channel impulse response above threshold in a time window centered around the position of the reference signal);
determining propagation time difference and digital synchronization error between each channel within the receiver electronics (“a Reference Pilot (i.e., the known local copy of the calibration signal) is used to adaptively equalize until convergence is obtained,” i.e., the time difference expressed, e.g., as phase difference with the local reference signal, is determined, and “outputting equalizer coefficients,” i.e., the digital synchronization error is calculated for each channel – See [¶0069]);
determining adjustment parameters, for synchronizing time alignment, for each channel (“performing a channel estimation first using local copies of the ZC sequence,” i.e., the reference signal, “may enable the receiver to derive an equalizer that determines the time offset, and frequency response of the channel associated with the receiver” – See [¶0037] and Fig. 4 at step 328);
adjusting the channels in the time domain in accordance with the determined adjustment parameters of synchronization for each channel (“the signal may be filtered with the equalizer coefficients derived at 314” whereby “these equalizer coefficients may be used by a filter DSP block that operates after the ADC. At the output of the time domain equalizer, calibrated digital samples of the ADC acquired waveform may be produced that are time aligned down to picoseconds, phase aligned and have the non-flat frequency response of the imperfect receiver removed” – See [¶0073] and Fig. 4 at step 328).
Therefore, Claim 1 is anticipated by Taher1.
Regarding Claim 5, dependent from Claim 1, Taher1 further teaches the method according to claim 1, wherein adjusting the channels comprise using an interpolation filter (“since the equalizer is half spaced, the time-domain samples may be routed to a decimating de-interleaver at 218 that outputs two streams of time domain samples, each operating at half rate” used to calculate equalizer coefficients – See [¶0045] and Fig. 3 showing also the decimating de-interleaver 248 before performing equalization on the received RF signals, i.e., “the decimating de-interleaver 248 may route the incoming time domain samples alternately to the even and odd sample paths 250-252” – See [¶0062] followed by a digital adjustment comprising the Fractionally Spaced-Frequency Domain Equalizer using “the same coefficients that were derived during the Cal Mode at 230” and “calibrated digital samples of the ADC acquired waveform may be produced that are time aligned down to picoseconds” – See [¶0063]; a person of ordinary skills in the art would appreciate that a “decimating de-interleaver” is a down-sampling filter within the meaning of an interpolation filter in the present application1).
Therefore, Claim 5 is anticipated by Taher1.
Regarding Claim 7, dependent from Claim 1, Taher1 further teaches the method according to claim 1, wherein adjusting the channels comprise at least one of using a shift register, and controlling a clock generation circuit of the ADC to adjust the phase of the outgoing signal (“With the 10 MHz clocks locked, the time alignment in the digitized ADC samples will hold for a long duration after applying the timing alignment calibration method” – See [¶0033] whereby “[a] further enhancement to this method may involve daisy chaining the Local Oscillators (LOs) that do the down conversion to ensure that the phase alignments also hold for a long duration after the disclosed method for calibration is complete” – See [¶0034]).
Therefore, Claim 7 is anticipated by Taher1.
Regarding Claim 8, dependent from Claim 1, further teaches the method according to claim 1, wherein the synchronization is performed at startup of the system (“after completion of the calibration process, the MIMO system may be configured to transition to an Operation Mode. After transitioning from the Cal Mode to Operation Mode, . . . the switches 110 may connect the radios 102-106 to the antennas 112-116, to allow the radios to receive signals from the antennas,” – See [¶0070] i.e., the synchronization is performed before putting the system in operation, e.g., at startup because although “an acquisition ADC start trigger may be shared between each receiver during Cal Mode and during Operation mode . . . there is likely to be several nanoseconds of residual timing misalignment between one ADC and another-hence the equalizer derived during Cal Mode may remove this timing mismatch and also phase align the receivers. After switching to the Operation Mode, the timing and phase alignment functions of the calibration equalizer previously derived may hold if all the N receivers' ADCs are initiated for acquisition together via the shared trigger” – See [¶0074]).
Therefore, Claim 8 is anticipated by Taher1.
Regarding Claim 9, dependent from Claim 1, Taher1 further teaches the method according to claim 1, wherein the synchronization is checked at pre-set intervals during operation of the system (“the data communication protocol used by the radios may be designed to automatically repeat the calibration step at pre-set intervals to improve MIMO performance,” e.g., “there may be time slots for calibration where data packets are not sent, but where real-time calibration of the phase, frequency and timing alignment is performed” – See [¶0076]).
Therefore, Claim 9 is anticipated by Taher1.
Regarding Claim 10, dependent from Claim 1, Taher1 further teaches the method according to claim 1, wherein the step of determining propagation time difference and digital synchronization error comprises:
for each channel, determining an actual sample distribution around a reference point in a pre-determined sample area in each of said time sample windows (when “[a] wideband complex correlation signal is received simultaneously by the multiple receivers through the switches … [e]ach receiver runs a correlator and the resulting correlation peaks or channel impulse responses have been plotted as a function of offset” around peak value(s) – See [¶0078], whereby “without employing the calibration techniques . . . [t]here are multiple peaks above the horizontal dotted line caused by the different frequency responses in each receiver” and “[t]he peaks in each of the 3 impulse response charts are a few samples wide and they do not perfectly overlap with each other” in a time sample window of around 0.2µs wherein the reference point is the maximum peak value – See [¶0080] and Fig. 5);
setting a desired sample distribution having evenly distributed samples around said reference point (e.g., distribution of “channel impulse response data (in dBm) for impulses obtained through correlation for 3 channels, after calibration has been performed . . . all the plots align very closely at the peak, showing excellent correlation” and “the correlation peak is narrow and one sample wide” with evenly distributed samples around the peak/reference point – See [¶0081] and Fig. 6);
determining a difference between each desired sample distribution and each actual sample distribution for each channel (“Reference Pilot (i.e., the known local copy of the calibration signal) is used to adaptively equalize until convergence is obtained, outputting equalizer coefficients” – See [¶0069] and step 314 in Fig. 4, wherein a “the time-domain equalization filter” determines the difference between each desired sample distribution of the reference pilot signal, sampled with the 10MHz clock, and each actual sample distribution for each channel obtained from the ADC 310 with the same sample period in the time domain sample window of around 0.2µ– See [¶0073] and Fig. 4);
comparing the difference between the channels (“The equalizer coefficients . . . remove the residual nanosecond timing offset between the various channels” – See [¶0057], i.e., the time-domain equalization filter above compares the differences between channels, e.g., to remove a common denominator or to avoid “a long convergence time during calibration” if one difference is too large – See [¶0073]).
Therefore, Claim 10 is anticipated by Taher1.
Regarding Claim 11, dependent from Claim 10, further teaches the method according to claim 10, wherein the reference point is a center point in said pre-determined sample area (e.g., as shown in Fig. 6, “the correlation peak is narrow and one sample wide” and “all the plots align very closely at the peak” – See [¶0081], i.e., the reference point is a center point in the pre-determined sample area of one periodicity, 100ns, of the sampling/reference signal).
Therefore, Claim 11 is anticipated by Taher1.
Regarding Claim 12, Taher 1 teaches in Fig. 1 a radio-frequency (RF) receiving system (Rx 102-106) for synchronizing time alignment in different receiver channels, the RF receiving system comprising: a plurality of antennas having antenna inputs (Antenna 1-3); a plurality of receiver channels (Switches 110); control circuitry (when implemented in a computer system, the receiving system is “configured to include a processor (or a set of processors)” executing program instructions “to implement any of the various method embodiments described” – See [¶0110]); wherein the control circuitry is configured to: perform the steps of Claim 1, received with the same language. Because Claim 1 is anticipated by Taher1, Claim 12 is also anticipated by Taher1.
Regarding Claim 13, teaches a non-transitory computer-readable storage medium storing one or more programs configured to be executed by one or more control circuitry of a multi-channel radio frequency receiver system (“the present invention may be realized as a computer-implemented method, a computer-readable memory medium, or a computer system” – See [¶0108] whereby “non-transitory computer readable memory medium may be configured so that it stores program instructions and/or data, where the program instructions, if executed by a computer system, cause the computer system to perform a method, e.g., any of a method embodiments described herein, or, any combination of the method embodiments described herein. or. any subset of any of the method embodiments described herein, or, any combination of such subsets” – See [¶0109]) the one or more programs comprising instructions for performing the method according to claim 1. Because Claim 1 is anticipated by Taher1, Claim 13 is also anticipated by Taher1.
Therefore Claims 1, 5, and 7-13 are rejected under 35 U.S.C. §102(a)(2) as anticipated by Taher1.
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.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 2-4 are rejected under 35 U.S.C. 103 as being unpatentable over Taher1 as applied to claim 1 above, and further in view of Taher et al., U.S. patent Application Publication No. 2019/0149198 (hereinafter Taher2).
Regarding Claim 2, dependent from Claim 1, Taher1 further teaches the method according to claim 1, wherein the channels are adjusted in the time domain by at least one of:
a coarse delay shift in the order of an integer number of analog-to-digital conversion, ADC, samples (“a processor at the receiver finds the Pilot Start, which comprises a coarse timing of the signal” – See [¶0068] and Fig. 5, showing that “peaks in each of the 3 impulse response charts are a few samples wide and they do not perfectly overlap with each other,” – See [¶0080] but “after calibration has been performed . . . the channels are now time aligned” because “the correlation peak is narrow and one sample wide,” – See [¶0081] i.e., the shift between channels in time domain is an integer number of digital samples).
To be sure, Taher2, like Taher1, teaches “systems, storage media, and methods for calibrating a multiple input multiple output (MIMO) radio system” – See [¶0004]. However, Taher2 also teaches a fine delay shift in the order of a fractional of ADC samples in accordance with the determined parameters for synchronization for each channel (the “wideband pilot signal transmitted to each receiver is used to determine a time delay to subsample precision associated with the transmission of the wideband pilot signal to the respective receiver” employing “a programmable delay based on the time delays to reduce a timing misalignment between the plurality of receivers in subsequent communications” – See [¶0005]).
Thus, Taher1 and Taher2 each teaches systems, storage media, and methods for calibrating a multiple input multiple output (MIMO) radio system to reduce time offsets between multiple channels using a common reference signal. A person of ordinary skill in the art before the effective filing date of the claimed invention would have understood that the sub-sample time alignment method taught by Taher2 could have been combined with the coarse sample level method in Taher1 because both serve the purpose of providing correction of time delay mismatches between the hardware comprised in the parallel channels of a MIMO receiver whereby each ADC in each channel is triggered by the same, shared, reference signal. Furthermore, a person of ordinary skill in the art would have been able to carry out the combination through techniques known in the art. Finally, the combination achieves the predictable result of obtaining very precise measurement of the flight time without the need for very high digital sampling rates required that put constraints and added expense to the hardware, as explained by Taher2.
Therefore, Claim 2 is obvious over Taher1 in view of Taher2.
Regarding Claim 3, dependent from Claim 1, Taher1 further teaches the method according to claim 1, wherein the reference signal is periodic signal (e.g., in determining the time window, “cross correlation of the received [reference signal] with a local copy of the sequence may begin at any point (without prior timing synchronization), e.g., because of the periodic nature of the transmitted signal, which may simplify signal processing architecture” – See [¶0058]). However, Taher1 does not teach the reference signal is a saw tooth signal.
Taher2 teaches that “[a] variety of wideband signals may be used as the pilot signal,” including “a frequency chirped wideband signal” wherein “implementation may be facilitated if the amplitude response of the wideband signal is relatively flat over the frequency bins” so that “the signal to noise ratio (SNR) at each frequency bin . . . is relatively the same; and so, the statistical estimate D [i.e., “the whole+fractional sample time delay”], may be more accurate” – See [¶0043], [¶0041]. Taher2 further teaches that the reference signal may be a saw tooth signal (“each of the plurality of receivers may receive a first wideband pilot signal from a signal generator . . . each of the plurality of receivers may share a local oscillator (LO)” and “the first wideband pilot signal may comprise at least one of a . . . multi-sine signal, and/or a frequency chirped wideband signal” – See [¶0061] and Fig. 1B, whereby a person of ordinary skills in the art would appreciate that a sawtooth signal is a multi-sine signal with a periodicity periodic corresponding to its fundamental frequency, e.g., the 10 MHz timing reference common to the ADC on each RX channel – See [¶0048] and Fig. 5, and diminishing harmonics, at a rate of 1/n, at integer (n) multiples of that frequency; furthermore, sawtooth signals have applications in channel sounders using sliding correlation2 – See [¶0091]).
Therefore, Claim 3 is obvious over Taher1 in view of Taher2.
Regarding Claim 4, dependent from Claim 3, Taher1 further teaches the method according to claim 3, wherein the saw tooth signal has a rise and fall time in the order of 1μs (“timing synchronization is based on either autocorrelation of the received signal or its cross-correlation with the original sequence” which “may begin at any point . . . e.g., because of the periodic nature of the transmitted signal,” – See [¶0058] i.e., is defined by the periodicity of the reference signal, e.g. 0.1 μs for 10MHz signal; see also Figs. 5-6 showing a cross-correlation window of 100ns, i.e., the saw tooth signal periodicity measured as the rise and fall time is right under1μs).
Therefore, Claim 4 is obvious over Taher1 in view of Taher2.
In sum, Claims 2-4 are rejected under 35 U.S.C. §103 as obvious over Taher1 in view of Taher2.
Claim 6 is rejected under 35 U.S.C. 103 as being unpatentable over Taher1 as applied to claim 4 above, in view of Taher2, and further in view of Gudovskiy et al., U.S. Patent Application No. 2018/0316482 (hereinafter Gudovskiy).
Regarding Claim 6, dependent from Claim 5, although Taher1 teaches the method according to claim 5, wherein the interpolation filter operates down sampling in an interpolation module, Taher1 does not teach that the interpolation filter operates also the steps of up-sampling and sample delay in the interpolation module.
Taher2 teaches “sub-sample time alignment of receivers in a MIMO communication system” whereby “[a]n analog time delay in the time domain may correspond to a measurable linear phase shift versus frequency in the digitized frequency domain of a signal” – See [¶0037] and Fig. 8, showing “a setup wherein a wideband waveform may be sent to a plurality of receivers” and “the sampling delay may be precisely measured in all the receivers and then the effective delay differences may be removed using features provided by the vector signal analyzers,” e.g., “using both a programmable delay block or a customizable equalization filter that includes a delay function” – See [¶0051]. The improvement of the filter with equalizer coefficients disclosed in Fig. 4 of Taher1 with a a customizable equalization filter that includes a sub-sample delay function as disclosed in Taher2 would be obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention motivated by the need to correct differences between time delays in the baseband signal with sub-sample precision using digital adjustments such as programmable delays.
Gudovskiy, like Taher1 in view of Taher2, teaches “[s]ystems and methods . . . in which a wireless receiver can be configured to digitally synchronize a receive sampling rate to a transmit sampling rate,” and further teaches “a digital interpolator controlled by a timing control unit with a timing offset estimator,” whereby, like block 314 in Taher1 that derives the finer granularity equalizer coefficients, “[t]he timing control unit can be configured to calculate and output parameters to the digital interpolator” – See [¶0023]. Furthermore, the digital interpolator in Gudovskiy is a programmable delay block or a customizable equalization filter for sub-samples delays like the one taught in Taher2, because “[t]he timing offset estimator can be configured to calculate and provide to the timing control unit a sampling period ratio control word and an instantaneous timing offset control word” – See [¶0023]. Therefore, Gudovskiy teaches the interpolation filter operates also the steps of up-sampling, down-sampling and sample delay in the interpolation module because the digital interpolation filter uses the sampling period ratio control word to adapt upwards or downwards the sampling frequency of the receiver and the instantaneous timing offset control word to adapt its sub-sample delay.
Thus, Taher1 in view of Taher2 and Gudovskiy each teaches systems and methods for correcting for a timing offset in a sampling signal of the receiver relative to a reference sampling signal using digital adjustments based on equalizer coefficients or control words applied to a digital filter buffering received signal samples. A person of ordinary skill in the art before the effective filing date of the claimed invention would have understood that the digital interpolator taught by Gudovskiy could have been substituted in for the programable filter controlled with equalizer coefficients on each of the multiple input multiple output (MIMO) radio channels taught by Taher1 in view of Taher2 because each of these blocks provides for reducing time offsets between the multiple channels using measured or estimates from a time synchronization control unit. Furthermore, a person of ordinary skill in the art would have been able to carry out the substitution through techniques known in the art. Finally, the substitution achieves the predictable result of applying cheaper digital interpolation methods that allow calibration of MIMO time synchronization through sampling rate correction in the digital domain, as taught by Gudovskiy.
Therefore, Claim 6 is obvious over Taher1 in view of Taher2, and further in view of Gudovskiy.
Claims 14 is rejected under 35 U.S.C. 103 as being unpatentable over Taher1 as applied to claim 12 above, and further in view of Papazian et al., "A Radio Channel Sounder for Mobile Millimeter-Wave Communications: System Implementation and Measurement Assessment," in IEEE Transactions on Microwave Theory and Techniques, vol. 64, no. 9, pp. 2924-2932, Sept. 2016, doi: 10.1109/TMTT.2016.2592530 (hereinafter Papazian).
Regarding Claim 14, dependent from Claim 12, Taher1 further teaches a vehicle comprising the RF receiving system according to claim 12 (“the MIMO radio device may be a measurement apparatus designed to perform channel sounding or other wireless measurements using cellular or another wireless technology,” e.g., mounted on a vehicle “for measuring radio channel conditions for cellular MIMO communications (e.g., 5G or NR communications)” – See [¶0025]).
Although it is general knowledge that vehicles have continuous wireless connectivity providing synchronization through GSSN/GPS and perform channel sounding3 to correct for differences in parameter estimates such as delay spread, delay window, or correlation bandwidth, Taher1 does not specifically disclose a vehicle comprising the RF receiving system.
Papazian discloses “the first sounder that is capable of mobile measurements at mm-wave frequencies” with a “delay resolution of the system is 1 ns” whereby “[t]he RX array is mounted on a location-aware robot, which is battery operated” – See Abstract, p2924, and “satisfy scenarios envisioned for 5G networks, such as massive-MIMO antenna arrays, vehicular speeds in device-to-device communications [10], and transmission of high-bandwidth signals” – See §I, col1:¶3, p 2925. Like Taher1, Papazian’s receiver uses “[d]igital correlation-based processing [18], [19] in which a high-speed digitizer acquires the received intermediate-frequency (IF) signal and correlation is performed in postprocessing. This reduces the measurement time of the channel impulse response to the duration of the codeword” – See id. Papazian further uses “[a] 16-element receive-antenna array oriented in both the azimuth and elevation directions whose field-of-view covers the upper hemisphere . . . allowing measurement of the impulse response across all 16 elements within 65.5μs” that “provides a maximum coherence time corresponding to vehicular speeds up to approximately 100 km/h” – See id., and “a portable rubidium clock for timing synchronization, with negligible drift over the 65.5-μs rotation. The receive system is global-positioning-system (GPS)-equipped for outdoor operation and robotically navigated with a laser range finder for indoor applications” – See §I, col2:¶1, p 2925 and Fig. 1 (c), p 2926.
Thus, Taher1 and Papazian each discloses a MIMO RF receiver equipped for measuring/calibrating time synchronization delays with sub-nanosecond precision. A person of ordinary skill in the art before the effective filing date of the claimed invention would have understood that the improvements to the MIMO RF receiver for channel sounding measurement/calibration when mounted on a vehicle, as taught in Papazian, could have been applied to the MIMO RF receiver of Taher1 because they share the same schematic based on digital correlation-based processing of a reference signal, including detection of the start block/codeword in the signal. Furthermore, a person of ordinary skill in the art would have been able to carry out the improvement through techniques known in the art. Finally, the improvement achieves the predictable result of expanding the application of the common schematic to vehicular mobility using 5G network, as taught by Papazian.
Therefore, Claim 14 is rejected under 35 U.S.C. §103 as obvious over Taher1 in view of Papazian.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure:
Carney et al., U.S. Patent Publication No. 5,537,435 discloses multichannel wireless communication transceiver architecture employing overlap and add or polyphase signal processing functionality, for wideband signal processing, including sample time adjustment;
Bierly et al., U.S. Patent Publication No. 6,421,372 discloses a parallel digital matched filter which performs numerous simultaneous correlations of a received spread spectrum signal against various replica offsets of its spreading sequence;
Fernandez et al., U.S. Patent Publication No. 7,148,828 discloses a method for calibrating time interleaved samplers comprising applying a calibration signal to a time-interleaved sampling device;
Pipon et al., Singapore Patent Application Publication No. SG1020161094 discloses methods of estimating interference noise using learning sequences known by the receiver, e.g., to carry out anti-jamming equalization using frequency interpolation;
Zheng et al, China Patent Application Publication No. CN104297738 discloses synchronization calibration device and synchronization calibration and error compensation method for multi-channel receiver;
Rossi, "Influence of measurement conditions on the evaluation of some radio channel parameters," in IEEE Transactions on Vehicular Technology, vol. 48, no. 4, pp. 1304-1316, July 1999, doi: 10.1109/25.775378;
Harris et al., "Multirate digital filters for symbol timing synchronization in software defined radios," in IEEE Journal on Selected Areas in Communications, vol. 19, no. 12, pp. 2346-2357, Dec. 2001, doi: 10.1109/49.974601;
Ferreira et al., Real-time high-resolution radio frequency channel sounder based on the sliding correlation principle. IET Microwave. Antennas Propagation, 9: 837-846, 2015, https://doi.org/10.1049/iet-map.2014.0165;
Seijo et al., "Portable Full Channel Sounder for Industrial Wireless Applications With Mobility by Using Sub-Nanosecond Wireless Time Synchronization," in IEEE Access, vol. 8, pp. 175576-175588, 2020, doi: 10.1109/ACCESS.2020.3025896.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to LUCIA GHEORGHE GRADINARIU whose telephone number is (571)272-1377. The examiner can normally be reached Monday-Friday 9:00am - 5:00pm EST.
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/L.G.G./ Examiner, Art Unit 2478
/JOSEPH E AVELLINO/ Supervisory Patent Examiner, Art Unit 2478
1 See, e.g., Specification, 4:23-24 (stating “interpolation filter may operate steps of up-sampling, sample delay, and down-sampling”). This is different from the general knowledge in the art whereby interpolation is the operation of up-sampling and decimation is the operation of down-sampling and whereby filters capable of performing both operations and also fractional delay on input signals are called polyphase filters – See, e.g., Section III, Harris et al., "Multirate digital filters for symbol timing synchronization in software defined radios," in IEEE Journal on Selected Areas in Communications, vol. 19, no. 12, pp. 2346-2357, Dec. 2001, doi: 10.1109/49.974601.
2 See, e.g., Ferreira et al., (2015), Real-time high-resolution radio frequency channel sounder based on the sliding correlation principle. IET Microwave. Antennas Propagation, 9: 837-846. https://doi.org/10.1049/iet-map.2014.0165
3 See, e.g., Seijo et al., "Portable Full Channel Sounder for Industrial Wireless Applications With Mobility by Using Sub-Nanosecond Wireless Time Synchronization," in IEEE Access, vol. 8, pp. 175576-175588, 2020, doi: 10.1109/ACCESS.2020.3025896