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 .
Response to Amendment
Claims 1-20 are presented for examination.
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 may not be obtained though the invention is not identically disclosed or described as set forth in section 102 of this title, if the differences between the subject matter sought to be patented and the prior art are such that the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art to which said subject matter pertains. Patentability shall not be negatived by the manner in which the invention was made.
The factual inquiries set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied 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.
Claims 1, 2, 4-16, and 18-20 are rejected under 35 USC 103 as being unpatentable over Sadr et al., U.S. 2010/0039228 in view of Pettus, U.S. 2005/0280539.
On claim 1, Sadr cites:
A method for a radio frequency identification (RFID) system to
estimate a location of an RFID tag, the method comprising:
transmitting, sequentially within a single inventory round, a first RF signal having a first frequency and a second RF signal having a second frequency, wherein the RFID system transitions from transmitting the first RF signal to the second RF signal during a command, at a portion of the command suitable for frequency switching;
figure 20 and [0081] cites:
[0074] Backscattered signals from RFID tags provide a variety of observables that can be used in location estimation. The observable used as a proxy for distance in the above discussion of transmit and receive antenna geometries is the calibrated slope of the group delay. Group delay describes the differences in phase observed at different frequencies. The manner in which group delay can be used in location estimation in accordance with embodiments of the invention is explained below. In several embodiments, observations of read rate are used in location estimation. An RFID tag's read rate can be generally described as the number of times the RFID tag is read as a ratio of the number of opportunities in which the RFID tag could have been read. Other observables that can be utilized in location estimation include, but are not limited to, phase, phase coefficient magnitude, read rate, carrier frequency, excitation node index, and receive antenna index.
[0081] Referring now to FIG. 20, one aspect of an array antenna RFID system operating in a near field mode in terms of its ability to locate RFID tags is shown. A simplified four-element array is shown in a 2D illustration of an example of the RFID tag location provided by the system. One skilled in the art would appreciate the extension of the 2D to an arbitrary array in 3D is achievable and contemplated. The RFID tag location technique is based on measuring a phase difference 9-1 of the arrival signals between a particular element 9-3 and a reference element 9-2 or a preamble signal. The phase difference 9-1 is proportional to the range difference (r.sub.2.degree.-r.sub.1.degree.) of the paths 9-4 and 9-5 between the RFID tag and the two array elements 9-2 and 9-3. In particular, the differential range is given by
where f is the carrier frequency of the RFID tag. The location of the RFID tag, uniquely determinable from x.sub.1, x.sub.2, x.sub.3, x.sub.4 and differential range (r.sub.2-r.sub.1), (r.sub.3-r.sub.1), (r.sub.4-r.sub.1)can be calculated from the known locations of the array elements (x.sub.i, y.sub.i) and the measured differential ranges from the very efficient algorithm…
And
[0050] During an interrogation round, processing operations may include but are not limited to: estimating the relative phase difference between the signals from each of the antenna elements and the reference signal and deriving the relative range from each of the antenna elements to the RFID tag in accordance with the adjusted phase delay difference for each such antenna element. Estimating the location of the RFID tag may then be dealt with by treating the aggregate interrogation rounds as a single data base forming a "sample space". It is also noted that reading the same RFID tag at multiple frequencies enables an estimation of the range (distance of the tag to the read point) of the signal source via "sequential ranging". For applications where only a single reader (read point) is deployed, the reader system is able to provide location estimation without the need to "triangulate".
(the claimed “command, suitable for switching” is provided for when the system disclosed in figure 20 does from 9-2 to 9-3, which may include changing frequencies as disclosed in [0050])
receiving, from the RFID tag and within the single inventory round, a first reply
backscatter-modulated on the first RF signal and a second reply backscatter-modulated on the second RF signal, wherein the second reply is in response to the command;
See above:
The RFID tag location technique is based on measuring a phase difference 9-1 of the arrival signals between a particular element 9-3 and a reference element 9-2 or a preamble signal
determining a first set of phase differences associated with the first reply and the second reply;
The phase difference 9-1 is proportional to the range difference (r.sub.2.degree.-r.sub.1.degree.) of the paths 9-4 and 9-5 between the RFID tag and the two array elements 9-2 and 9-3.
correlating the first set of phase differences to a at least a first plurality of sets of candidate phase differences candidates, wherein each set of candidate phase differences is computed based on associated with a respective candidate tag and candidate location; and
estimating, based on the correlation, a first location of the RFID tag.
[0081] The location of the RFID tag, uniquely determinable from x.sub.1, x.sub.2, x.sub.3, x.sub.4 and differential range (r.sub.2-r.sub.1), (r.sub.3-r.sub.1), (r.sub.4-r.sub.1)can be calculated from the known locations of the array elements (x.sub.i, y.sub.i) and the measured differential ranges from the very efficient algorithm…
Regarding the excepted claim limitations, Sadr, [0081] discloses an embodiment for determining the location of an RFID tag. However, Sadr did not disclose the excepted “correlating the first set of phase differences to a at least a first plurality of sets of candidate phase differences candidates, wherein each set of candidate phase differences is computed based on associated with a respective candidate tag and candidate location.”
In the same art of RFID tracking, Pettus cites:
[0065] and figure 1A cites:
Ordinary backscatter reflection from objects other than RFID tags will be received by the interrogator 100 and will have random polarization and phase compared to the antenna elements of on the tag(s). Thus, antennas with known phase and polarization parameters are printed into the coded pattern at known relative locations to establish an a priori reference return signal. This technique provides an effective method to lock onto the tag 200 and create a phase and polarization decoding reference for the interrogator.
In other words, while there might be certain RFID tags with different polarization and phase parameters received at the interrogator, only signals received at antennas with known phase and polarization parameters will be considered a reference or known signal.
It would have been obvious to one of ordinary skill before the effective filing date of the claimed invention to include into Sadr the RFID location and identification system of Pettus such that the claimed invention is realized.
Pettus discloses a known embodiment in which interrogators possessing antennas with known phase and polarization patterns are calibrated to receive transponder signals at those specific phases, and therefore, at those specific locations. Thus, one of ordinary skill, apprised of this feature, would have included this option into Sadr as a known alternative embodiment for determining the location and identity of a tag based on signals received at those known phases.
On claim 2, Sadr cites:
The method of claim 1, wherein the first reply and the second reply are in response to successive commands from an RFID reader, wherein successive commands include the command.
[0059] Referring now to FIG. 6, a RFID reader interrogating a group of RFID tags placed on a number of inventory items as arranged on a pallet in accordance with an embodiment of the invention is shown. The RFID system operates in the presence of interference from an exemplary interferer 6-10. The pallet of goods 6-1 includes many cases or items tagged with RFID passive tags. A transmitted interrogation signal 6-4 from an antenna 6-6 impinges upon the pallet 6-1. In response to the signal energy detected by each tag, each tag may backscatter a sequence of information using the power received from the transmitted interrogation signal or beam 6-4. In the environment, there may be man-made or natural interferences illustrated as an interferer 6-10.
And
[0049] Multiple RFID tag interrogation signals can be transmitted at different frequencies during each interrogation round. Interrogating a tag using different frequencies enables additional observation of the tag to accurately model the received signal phase and amplitude trajectories over time, and characterize the signal dispersion with multipath reflections of the transmitted signal.
(the claimed first and second replies are responses to the cited different frequencies emanating from the interrogator)
And
Figure 18 and [0085] Referring now to FIG. 19, the operation provided in FIG. 18 is repeated (8-7). The repeated operation produces multiple read points. Utilizing these multiple reads and thus the information or distance estimations of the RFID tag, a probability distribution model is formed (8-8).
(the claimed “successive command” is the repeated interrogation).
On claim 4, Sadr cites except as underlined:
The method of claim 1, wherein the first reply and the second reply include the same data.
Sadr, as previously disclosed:
[0075] and figure 18. The RFID receiver system causes the RFID tag to respond in which the information signals differ in frequency only and the system determines the phase difference between the different information signals.
Sadr doesn’t disclose the excepted claim limitations. However, it would have been obvious to one of ordinary skill in the art at the time of the claimed invention to include into Sadr the added feature of the first and second replies to an interrogation including the same data as each other. One of ordinary skill would have include redundant information to ensure the receiving station had a higher chance of receiving the responsive information.
On claim 5, Sadr cites:
The method of claim 1, wherein the first RF signal and the second RF signal are transmitted by a single reader employing fast frequency switching.
[0047] The controller may utilize frequency hopping (while satisfying regulatory requirements) to schedule frequency channel use for each exciter. FIGS. 4A-B illustrate an example of the exciter layout (4-6) and the time line (4-4) showing the assigned frequency channels (4-8). The timeline (4-4) depicts frequency-hopped channelization in the 900 MHz ISM band (4-10). On each timeline, a different hopping sequence effectively assigns a distinct series of random frequencies to each active exciter (4-8). The algorithms described in FIG. 14, manage and optimize this activity.
On claim 6, Sadr cites except as underlined:
The method of claim 1, wherein determining the first set of phase differences comprises:
determining an initial set of phase differences;
[0076] Assuming that the exciter location from the reader is known, the received phase of the tag signal at the reader is measured. If a different tone frequency is used, a different relative phase will be measured. The difference in measured relative phases of the two tones at two different frequencies due to the round trip delay is related to the differential frequency via (assuming the exciter is co-located with the reader):
where .DELTA..phi. is differential relative phases, .DELTA.f is differential frequency, d is distance, and c is the speed of light. The phase .theta..sub.1 at tone frequency f.sub.1 can be measured with a 2m.pi. ambiguity. Similarly the phase at tone frequency f.sub.2 can be measured with a 2n.pi. ambiguity. As long as the differential phase is less than 2.pi., the phase difference of the modulo 2.pi. measurements can be used to determine the range d given .DELTA.f. This is true as long as .DELTA..phi. is less than 2.pi.. Note that the condition can be satisfied by selecting the appropriate frequency separation given the expected range of operation. From the range d and bearing .theta., the tag location can be determined for the two-dimensional example. One skilled in the art would appreciate the extension to 3D is achievable and contemplated. When the exciter is not co-located with the reader and has distance d.sub.1 to the tag, then
and
removing at least one of an additive reader phase
[0058] Through periodical calibrations, the beam former may compensate for mismatches and imperfections of RF microwave devices in the front end (between the antenna and analog-digital converters (ADCs) for the receive path and between the digital-analog converters (DACs) and the antenna for the transmit path) as well as mismatches in phase and amplitude from RF-to-baseband from multiple independent parallel array element paths.
and an additive tag phase from the initial set of phase differences to generate the first set of phase differences.
[0091] Next the measurement update (25-6) process computes likelihoods associated to each particle given the new measurement. The resulting likelihood is the product of the likelihoods that each observation (for instance phasor, or read rate measure) correspond to given the expected phase between eNode to tag and tag to antenna element distances. These probabilities can be evaluated with, in one embodiment, a Gaussian distribution that uses a standard deviation which depends on the receive power on the antenna when the observation is taken and also on the reliability associated with the estimated calibration coefficient. Calibration coefficients are used on each tag-read measurement in order to remove any effects that don't correspond to wave propagation. In one embodiment, given that the distance between an excitation point and a receive patch in known, one can remove excess phase rotation at each frequency compared to observed phase using a `backchannel` waveform or reference tag that is co-located with the excitation point (25-10). The amount of removed excess rotation at each frequency is recorded and `backed-out` of subsequent received tag measured phase data in order to compensate for phase rotation effects not due to radio propagation (such as electronic delay).
(per the applicant’s specification, [0078] This change of the phase by the reader or tag system can be referred to as “additive phase”. Characterization (also referred to as “calibration”) of the additive phase for the reader system or tag can allow an RFID system to remove or compensate for (in a process that can be referred to as “compensation”) the effective change of phase on the radio wave to more accurately determine (a) the propagation distance of the radio wave and (b) the tag location)
Regarding the excepted: removing at least one of an additive reader phase, Sadr, [0058], disclosed compensation of beam forming features as indicated. Included in that citation are “periodical calibrations.” Sadr doesn’t specifically disclose these calibrations as “additive reader phases.” However, it would have been obvious to one of ordinary skill in the art at the time of the claimed invention to try and include into Sadr the feature of calibrating the reader such that the claimed invention is realized. While Sadr doesn’t specifically disclose an “additive reader phase,” one of ordinary skill would have recognized the cited “calibration” as including an adjustment to bring mismatches in phase such that the claimed invention is realized. In this “calibration,” the claimed “additive” reader phase requires compensation. Thus, one of ordinary skill, apprised of the need to adjust for this parameter, would have included at least the adjustment of an “additive phase” such that the cited reader reaches an increase or optimal performance in that calibration. .
Regarding the excepted: removing at least one of an additive tag phase, Sadr, [0091], disclosed calibration coefficients are used on each tag-read measurement in order to remove any effects that don't correspond to wave propagation. In one embodiment, given that the distance between an excitation point and a receive patch in known, one can remove excess phase rotation at each frequency compared to observed phase using a `backchannel` waveform or reference tag that is co-located with the excitation point (25-10). The amount of removed excess rotation at each frequency is recorded and `backed-out` of subsequent received tag measured phase data in order to compensate for phase rotation effects not due to radio propagation (such as electronic delay). Sadr doesn’t specifically disclose these calibrations as “additive tag phases.” However, it would have been obvious to one of ordinary skill in the art at the time of the claimed invention to try and include into Sadr the feature of calibrating the tag read information such that the claimed invention is realized. While Sadr doesn’t specifically disclose an “additive tag phase,” one of ordinary skill would have recognized the cited “calibration” as including an adjustment to bring the mismatches in phase such that the claimed invention is realized. In this “calibration,” the claimed “additive” tag phase would be any deviations in phases that would lead to a degradation in performance in an “out of calibration” condition. Thus, one of ordinary skill, apprised of this known adjustable parameter, would have included at least the adjustment of an “additive phase” such that the cited tag reaches an increase or optimal performance in that calibration.
On claim 7, Sadr cites except as underlined:
The method of claim 1, wherein:
correlating the first set of phase differences to the plurality of candidates comprises attempting to determine whether a single candidate has a significant correlation probability; and
estimating the first location of the RFID tag comprises:
if only the single candidate has the significant correlation probability, then estimating the location associated with the single candidate as the first location of the RFID tag.
[0040] Due to instability in the RFID backscatter process, the observables that are chosen when performing location estimation can influence the accuracy of the resulting estimates. In various embodiments, the system observes the phase difference of backscattered signals from illuminated RFID tags. In several embodiments, the phase differences are observed at different transmit frequencies to provide range information.
And, Figure 13a and [0069] discloses:
[0069] Turning now to FIGS. 13-16, exemplary excitation nodes or eNode configurations are shown. For example, in FIGS. 13A-D, observations of an RFID tag obtained by a `4-port` eNode configured as a "chandelier" and the different ports act as the exciter is shown. In the chandelier configuration, each of the antenna elements is set equidistance from each other and is set in a square like shape. The 4-port eNode maintains phase synchronization between transmit and receive points using a local oscillator or via an external reference. The view is from overhead and shows eNode setup such that 3 of 4 ports receive (21-1, 21-2 and 21-3 in FIG. 13A) and 1 transmits (21-5 in FIG. 13A). The tag of interest is denoted with a square (21-4). In each figure, three ellipses are displayed. Each ellipse shares a TX antenna for one focus and has a different receiving antenna as another focus. The intersection of all three ellipses can be taken as an observation of tag location. In situations where this intersection is not unique (not shown here) information regarding which antenna excited the tag can be used to identify the most likely 3-way intersection. In one embodiment, the phase of a received tag signal is determined via correlation with a preamble sequence. Such an approach is described in U.S. patent application Ser. No. 11/770,712, filed Jun. 28, 2007, entitled "RFID Beam Forming System", the disclosure of which is hereby incorporated by reference as if set forth in full herein.
Regarding the excepted claim limitations:
correlating the first set of phase differences to the plurality of candidates comprises attempting to determine whether a single candidate has a significant correlation probability, Sadr, while disclosing determining range information as a result of determining phase differences, Sadr doesn’t disclose the excepted claim limitation. However, Sadr discloses:
[0091] Next the measurement update (25-6) process computes likelihoods associated to each particle given the new measurement. The resulting likelihood is the product of the likelihoods that each observation (for instance phasor, or read rate measure) correspond to given the expected phase between eNode to tag and tag to antenna element distances. These probabilities can be evaluated with, in one embodiment, a Gaussian distribution that uses a standard deviation which depends on the receive power on the antenna when the observation is taken and also on the reliability associated with the estimated calibration coefficient. Calibration coefficients are used on each tag-read measurement in order to remove any effects that don't correspond to wave propagation. In one embodiment, given that the distance between an excitation point and a receive patch in known, one can remove excess phase rotation at each frequency compared to observed phase using a `backchannel` waveform or reference tag that is co-located with the excitation point (25-10). The amount of removed excess rotation at each frequency is recorded and `backed-out` of subsequent received tag measured phase data in order to compensate for phase rotation effects not due to radio propagation (such as electronic delay).
Furthermore, as previously disclosed, Pettus cites:
[0065] and figure 1A cites:
Ordinary backscatter reflection from objects other than RFID tags will be received by the interrogator 100 and will have random polarization and phase compared to the antenna elements of on the tag(s). Thus, antennas with known phase and polarization parameters are printed into the coded pattern at known relative locations to establish an a priori reference return signal. This technique provides an effective method to lock onto the tag 200 and create a phase and polarization decoding reference for the interrogator.
It would have been obvious to one of ordinary skill before the effective filing date of the claimed invention to include into Sadr the added feature of determine the location of a tag based on known phases associated with the tag wherein the measured phases present a likelihood of identifying a particular tag. One of ordinary skill, apprised with these known techniques, would have applied them to determine the distance and identify of a particular tag such that the claimed invention is realized.
On claim 8, Sadr and Pettus cites except as underlined:
The method of claim 1, further comprising:
transmitting, sequentially within another inventory round, a third RF signal having a third frequency and a fourth RF signal having a fourth frequency;
receiving from the RFID tag, within the other inventory round, a third reply backscatter- modulated on the third RF signal and a fourth reply backscatter-modulated on the fourth RF signal;
determining a second set of phase differences associated with the third reply and the fourth reply;
correlate correlating the second set of phase differences to the plurality of sets of candidate phase differences;
estimating, based on the correlation of the second set of phase differences, a
second location of the RFID tag; and
estimating, based on at least the first location and the second location, a movement of the RFID tag.
In the rejection of claim 1, Sadr and Pettus disclosed an embodiment involving a single inventory round in which a tag is interrogated by different reader/antenna combinations. As disclosed in Sadr, figure 20, the tag is being interrogated by different readers at locations at 1, 2, 3, and 4. Furthermore, Pettus discloses using antennas of known phase and locations to establish a likelihood of a location of an RFID tag. However, neither Sadr nor Pettus discloses the excepted claim limitations.
However, it would have been obvious to one of ordinary skill before the effective filing date of the claimed invention to include into Sadr the features disclosed in Pettus and the embodiment disclosed in claim 1 to provide an embodiment meeting the claimed invention. Neither Sadr nor Pettus specifically disclose an embodiment where “another inventory round” disclosed in the claimed embodiment is being carried out. However, one of ordinary skill, apprised of the operations of interrogating a tag as disclosed in claim 1, would logically surmise that a separate and repeated interrogation of the cited tag in figure 20 would produce similar results as disclosed in the rejection of claim 1.
On claim 9, Sadr cites:
The method of claim 1, wherein:
receiving the first reply and the second reply comprises receiving the first reply and the second reply at each of a first antenna and a second antenna;
figure 20 and [0081] One skilled in the art would appreciate the extension of the 2D to an arbitrary array in 3D is achievable and contemplated. The RFID tag location technique is based on measuring a phase difference 9-1 of the arrival signals between a particular element 9-3 and a reference element 9-2 or a preamble signal.
These signals are received at antenna elements 1 and 2.
and the first set of phase differences comprises phase differences of the first reply and the second reply with regard to the first antenna
figure 20, and [0081] phase difference 9-1 of replies to antenna array elements 1 and 2.
and phase differences of the first reply and the second reply with regard to the second antenna.
figure 20, and [0081] phase difference 9-1 of replies to antenna array elements 1 and 2.
On claim 10, Sadr cites except as underlined:
A method for a radio frequency identification (RFID) system to estimate a velocity of an RFID tag, the method comprising:
transmitting, within a first inventory round, a first set of successive RF signals, wherein each RF signal in the first set of RF signals has a different frequency and the RFID system transitions between transmitting two successive RF signals in the first set at a first RF signal portion suitable for frequency switching;
[0074] Backscattered signals from RFID tags provide a variety of observables that can be used in location estimation. The observable used as a proxy for distance in the above discussion of transmit and receive antenna geometries is the calibrated slope of the group delay. Group delay describes the differences in phase observed at different frequencies. The manner in which group delay can be used in location estimation in accordance with embodiments of the invention is explained below. In several embodiments, observations of read rate are used in location estimation. An RFID tag's read rate can be generally described as the number of times the RFID tag is read as a ratio of the number of opportunities in which the RFID tag could have been read. Other observables that can be utilized in location estimation include, but are not limited to, phase, phase coefficient magnitude, read rate, carrier frequency, excitation node index, and receive antenna index.
[0037] FIG. 27 is a conceptual illustration showing application of autonomous perpetual inventory to items stored on vertically racked shelves.
[0050] During an interrogation round, processing operations may include but are not limited to: estimating the relative phase difference between the signals from each of the antenna elements and the reference signal and deriving the relative range from each of the antenna elements to the RFID tag in accordance with the adjusted phase delay difference for each such antenna element. Estimating the location of the RFID tag may then be dealt with by treating the aggregate interrogation rounds as a single data base forming a "sample space". It is also noted that reading the same RFID tag at multiple frequencies enables an estimation of the range (distance of the tag to the read point) of the signal source via "sequential ranging". For applications where only a single reader (read point) is deployed, the reader system is able to provide location estimation without the need to "triangulate".
receiving a first set of replies from the RFID tag during the first inventory round, wherein at least two replies in the first set of replies are each backscatter-modulated on a different RF signal in the first set of RF signals;
[0059] A transmitted interrogation signal 6-4 from an antenna 6-6 impinges upon the pallet 6-1.
transmitting, within a second inventory round, a second set of successive RF signals, wherein each RF signal in the second set of RF signals has a different frequency and the RFID system transitions between transmitting two successive RF signals in the second set at a second RF signal portion suitable for frequency switching;
receiving a second set of replies from the RFID tag during the second inventory round, wherein at least two replies in the second set of replies are each backscatter-modulated on a different RF signal in the second set of RF signals;
determining a first set of phase differences associated with the first set of replies;
[0081] Referring now to FIG. 20, one aspect of an array antenna RFID system operating in a near field mode in terms of its ability to locate RFID tags is shown. A simplified four-element array is shown in a 2D illustration of an example of the RFID tag location provided by the system. One skilled in the art would appreciate the extension of the 2D to an arbitrary array in 3D is achievable and contemplated. The RFID tag location technique is based on measuring a phase difference 9-1 of the arrival signals between a particular element 9-3 and a reference element 9-2 or a preamble signal. The phase difference 9-1 is proportional to the range difference (r.sub.2.degree.-r.sub.1.degree.) of the paths 9-4 and 9-5 between the RFID tag and the two array elements 9-2 and 9-3.
determining a second set of phase differences associated with the second set of replies;
correlating the first set of phase differences and the second set of phase differences to a plurality of sets of candidate phase differences, wherein each set of candidate phase differences is computed based on associated with a respective candidate tag and velocity; and estimating, based on the attempted correlation, the velocity of the RFID tag.
[0003] An RFID system conventionally includes a set of stationary or mobile RFID tags typically manipulated by a reader/interrogator system. Each sensor may be passive or active, i.e., with or without a battery. In conventional systems, the reader and the RFID tags are generally required to be in close proximity so that the tags can operate in close proximity to the reader antenna.
[0090] As an example, if we wish to estimate the location of tags moving on a forklifts the new velocity is limited to the velocities that can be obtained by an acceleration of 1G or less in each direction. There's also a maximum absolute value of velocity that the forklift can have. The time update process is separate from the regularization step in principle, but is dependent in implementation, since both time update and regularization add noise to state particles
Regarding the excepted:
determining a second set of phase differences associated with the second set of replies, Sadr, as indicated above, discloses at least “perpetual inventorying,” as well as determining phase differences from different transmitters towards the cited tag. Sadr didn’t disclose a “second set of phase differences.”
However, it would have been obvious to one of ordinary skill before the effective filing date of the claimed invention to include into Sadr the features previously disclosed as used for the first set of phase differences to provide an embodiment meeting the claimed invention. Sadr discloses an embodiment where “a second set of phase differences” disclosed in the claimed embodiment is being carried out. However, one of ordinary skill, apprised of the operations of interrogating a tag as disclosed in Sadr, would logically surmise that a separate and repeated interrogation of the cited tag in figure 20 would produce similar results as disclosed for the first set of phase differences.
Regarding the excepted: correlating the first set of phase differences and the second set of phase differences to a plurality of sets of candidate phase differences, wherein each set of candidate phase differences is computed based on associated with a respective candidate tag and velocity; and estimating, based on the attempted correlation, the velocity of the RFID tag.
Sadr cites:
[0081] The location of the RFID tag, uniquely determinable from x.sub.1, x.sub.2, x.sub.3, x.sub.4 and differential range (r.sub.2-r.sub.1), (r.sub.3-r.sub.1), (r.sub.4-r.sub.1)can be calculated from the known locations of the array elements (x.sub.i, y.sub.i) and the measured differential ranges from the very efficient algorithm…
In the same art of RFID tracking, Pettus cites:
[0065] and figure 1A cites:
Ordinary backscatter reflection from objects other than RFID tags will be received by the interrogator 100 and will have random polarization and phase compared to the antenna elements of on the tag(s). Thus, antennas with known phase and polarization parameters are printed into the coded pattern at known relative locations to establish an a priori reference return signal. This technique provides an effective method to lock onto the tag 200 and create a phase and polarization decoding reference for the interrogator.
In other words, while there might be certain RFID tags with different polarization and phase parameters received at the interrogator, only signals received at antennas with known phase and polarization parameters will be considered a reference or known signal.
It would have been obvious to one of ordinary skill before the effective filing date of the claimed invention to include into Sadr the RFID location and identification system of Pettus such that the claimed invention is realized.
Pettus discloses a known embodiment in which interrogators possessing antennas with known phase and polarization patterns are calibrated to receive transponder signals at those specific phases, and therefore, at those specific locations. Correlating of the first and second phase differences is merely taking multiple phase measurements to determine the location and velocity of a tag.
Thus, one of ordinary skill, apprised of this feature, would have included Pettus option into Sadr as a known alternative embodiment for determining the location, velocity, and identity of a tag based on signals received at those known phases.
On claim 11, Sadr and Pettus cites:
A method for a radio frequency identification (RFID) system to estimate a location of an RFID reader antenna, the method comprising:
transmitting, from the RFID antenna, sequentially within a single inventory round, a first RF signal having a first frequency and a second RF signal having a second frequency, wherein the RFID system transitions from transmitting the first RF signal to the second RF signal during a command, at a portion of the command suitable for frequency switching;
receiving, from an RFID tag and within the single inventory round, a first reply
backscatter-modulated on the first RF signal and a second reply backscatter-modulated on the second RF signal, wherein the second reply is in response to the command;
determining a first set of phase differences associated with the first reply and the second reply;
correlating the first set of phase differences to a plurality of sets of candidate phase differences candidates, wherein each set of candidate phase differences is computed based on associated with a respective location; and
estimating, based on the correlation, a first location of the RFID reader antenna.
See the rejection of claim 1 which discloses the same subject matter as claim 11 and is rejected for the same reasons.
On claim 12, Sadr and Pettus cites:
The method of claim 11, further comprising:
transmitting, sequentially within another inventory round, a third RF signal having a third frequency and a fourth RF signal having a fourth frequency;
receiving from the RFID tag, within the other inventory round, a third reply backscatter-
modulated on the third RF signal and a fourth reply backscatter-modulated on the fourth RF signal;
determining a second set of phase differences associated with the third reply and the fourth reply;
attempting to correlate correlating the second set of phase differences to at least a second the plurality of sets of candidate phase differences candidates, wherein each set of candidate phase differences is computed based on associated with a respective location; estimating, based on the attempted correlation of the second set of phase differences, a second location of the RFID reader antenna; and estimating, based on at least the first location and the second location, a movement of the RFID reader antenna.
See the rejection of claim 8, which discloses the same subject matter as claim 12 and is rejected for the same reasons.
On claim 13, Sadr cites:
The method of claim 11, wherein the RFID tag is one of stationary or moving.
[0003] An RFID system conventionally includes a set of stationary or mobile RFID tags typically manipulated by a reader/interrogator system.
or moving.
[0090] . As an example, if we wish to estimate the location of tags moving on a forklifts the new velocity is limited to the velocities that can be obtained by an acceleration of 1G or less in each direction.
On claim 14, Sadr cites except as underlined:
A method for a radio frequency identification (RFID) system to estimate a velocity of an RFID reader antenna, the method comprising: transmitting, within a first inventory round, a first set of successive RF signals, wherein each RF signal in the first set of RF signals has a different frequency and the RFID system transitions between transmitting two successive RF signals in the first set at a first RF signal portion suitable for frequency switching; receiving a first set of replies from an RFID tag during the first inventory round, wherein at least two replies in the first set of replies are each backscatter-modulated on a different RF signal in the first set of RF signals;
transmitting, within a second inventory round, a second set of successive RF signals,
wherein each RF signal in the second set of RF signals has a different frequency and the RFID system transitions from between transmitting two successive RF signals in the second set at a second RF signal portion suitable for frequency switching;
receiving a second set of replies from the RFID tag during the second inventory round, wherein at least two replies in the second set of replies are each backscatter-modulated on a different RF signal in the second set of RF signals;
determining a first set of phase differences associated with the first set of replies;
determining a second set of phase differences associated with the second set of replies;
attempting to correlate correlating the first set of phase differences and the second set of phase differences to a plurality of computed candidates, wherein each candidate is computed based on associated with a respective candidate velocity of the RFID reader antenna; and
estimating, based on the attempted correlation, the velocity of the RFID reader antenna.
See the rejection of claim 10, which discloses the same subject matter as claim 14 and is rejected for the same reasons.
On claim 15, Sadr cites:
The method of claim 14, wherein the RFID tag is one of stationary
[0003] An RFID system conventionally includes a set of stationary or mobile RFID tags typically manipulated by a reader/interrogator system.
or moving.
[0090] . As an example, if we wish to estimate the location of tags moving on a forklifts the new velocity is limited to the velocities that can be obtained by an acceleration of 1G or less in each direction.
On claim 16, Sadr cites: The method of claim 1, wherein the portion of the command is a low-amplitude portion.
Sadr cites:
[0058] Through periodical calibrations, the beam former may compensate for mismatches and imperfections of RF microwave devices in the front end (between the antenna and analog-digital converters (ADCs) for the receive path and between the digital-analog converters (DACs) and the antenna for the transmit path) as well as mismatches in phase and amplitude from RF-to-baseband from multiple independent parallel array element paths.
Digital signals include “1s” and “0s” in its data stream. Accordingly, the claimed “low-amplitude portion,” would include the “0” aspect of the digital signal.
On claim 18, Sadr cites:
The method of claim 10, wherein at least one of the first and second RF signal portions is a low-amplitude, modulated RF signal portion.
Sadr cites:
[0058] Through periodical calibrations, the beam former may compensate for mismatches and imperfections of RF microwave devices in the front end (between the antenna and analog-digital converters (ADCs) for the receive path and between the digital-analog converters (DACs) and the antenna for the transmit path) as well as mismatches in phase and amplitude from RF-to-baseband from multiple independent parallel array element paths.
Digital signals include “1s” and “0s” in its data stream. Accordingly, the claimed “low-amplitude portion,” would include the “0” aspect of the digital signal.
On claim 19, Sadr cites:
The method of claim 11, wherein the portion of the command is a low-amplitude portion.
Sadr cites:
[0058] Through periodical calibrations, the beam former may compensate for mismatches and imperfections of RF microwave devices in the front end (between the antenna and analog-digital converters (ADCs) for the receive path and between the digital-analog converters (DACs) and the antenna for the transmit path) as well as mismatches in phase and amplitude from RF-to-baseband from multiple independent parallel array element paths.
Digital signals include “1s” and “0s” in its data stream. Accordingly, the claimed “low-amplitude portion,” would include the “0” aspect of the digital signal.
On claim 20, Sadr cites:
The method of claim 14, wherein at least one of the first and second RF signal portions is a low-amplitude, modulated RF signal portion.
Sadr cites:
[0058] Through periodical calibrations, the beam former may compensate for mismatches and imperfections of RF microwave devices in the front end (between the antenna and analog-digital converters (ADCs) for the receive path and between the digital-analog converters (DACs) and the antenna for the transmit path) as well as mismatches in phase and amplitude from RF-to-baseband from multiple independent parallel array element paths.
Digital signals include “1s” and “0s” in its data stream. Accordingly, the claimed “low-amplitude portion,” would include the “0” aspect of the digital signal.
Claims 3 and 17 are rejected under 35 USC 103 as being unpatentable over Sadr et al., U.S. 2010/0039228 in view of Pettus, U.S. 2005/0280539 and Alouaz et al., U.S. 2007/0236335.
On claim 3, Sadr cites except as underlined:
The method of claim 2, wherein the successive commands are ACK commands according to the Gen2 Protocol.
Sadr, as previously disclosed:
[0059] Referring now to FIG. 6, a RFID reader interrogating a group of RFID tags placed on a number of inventory items as arranged on a pallet in accordance with an embodiment of the invention is shown.
Sadr didn’t disclose the interrogation as having a Gen2 protocol with ACK commands.
In the same art of RFID systems, Alouaz, discloses:
[0116] In part (B) of FIG. 9, reference numeral 950 generally refers to a linked timing example in which multiple tags reply in a slot. In this case, the replies are said to be collided. In this example, the reader issues a Query command 952 and multiple tags reply with their respective RN16 responses 954. In this case, a collision is detected and so the reader issues a QueryRep command 956. When no reply is detected within the time periods denoted by T1+T3, the reader issues a second QueryRep command 958. Following this, a single tag response is detected, in this case an RN16 response 960. Then, within the time period denoted T2, the reader transmits an ACK command 962, and then another QueryRep command 964. The second QueryRep command 964 is transmitted by the reader since no reply was received within the time period T1+T3. In the Gen2 Spec, T1 is defined as the time from interrogator/reader transmission to a tag response, and T3 is defined as the time an interrogator/reader waits, after T1, before it issues another command.
It would have been obvious to one of ordinary skill in the art at the time of the claimed invention to include into Sadr’s transmission the Gen2 RFID transmission protocol disclosed in Alouaz, which includes an “ACK” or acknowledgement command. One of ordinary skill would have included such RFID language as a common standard.
On claim 17, Sadr cites except as underlined:
The method of claim 1, wherein the portion of the command is a delimiter according to the Gen2 Protocol.
Sadr, as previously disclosed:
[0059] Referring now to FIG. 6, a RFID reader interrogating a group of RFID tags placed on a number of inventory items as arranged on a pallet in accordance with an embodiment of the invention is shown.
Sadr didn’t disclose the interrogation as having a Gen2 protocol with a delimiter.
In the same art of RFID systems, Alouaz, discloses:
[0033] Encoding the data in waveforms can be performed in a number of different ways. For example, protocols are devised to communicate in terms of symbols, also called RFID symbols. A symbol for communicating can be a delimiter, a calibration symbol, and so on. Further symbols can be implemented for ultimately exchanging binary data, such as "0" and "1", if that is desired. In turn, when the waveforms are processed internally by reader 110 and tag 120, they can be equivalently considered and treated as numbers having corresponding values, and so on.
It would have been obvious to one of ordinary skill in the art at the time of the claimed invention to include into Sadr’s transmission the Gen2 RFID transmission protocol disclosed in Alouaz, which includes a delimited. One of ordinary skill would have included such RFID functions as part of a common standard.
Response to Arguments
Claim 1 claims, in part, “transmitting, sequentially within a single inventory round, a first RF signal having a first frequency and a second RF signal having a second frequency, wherein the RFID system transitions from transmitting the first RF signal to the second RF signal during a command, at a portion of the command suitable for frequency switching,” "correlating the first set of phase differences to a plurality of sets of candidate phase differences, wherein each set of candidate phase differences is computed based on a respective candidate tag and candidate location," and "estimating, based on the correlation, a first location of the RFID tag."
Applicant arguments regarding the rejection of claim 1 based on the claim limitations cited under item 6 above have been carefully reviewed. However, these limitations were not previously examined in any prior Office Action since the amendments require a new search and consideration. Thus, this makes the applicant’s arguments moot.
For the same reasons articulated under item 7 above, the applicant’s arguments regarding the rejection of claims 3, 4, 6, and 8 are also moot.
Claim 10 includes similar amended subject matter articulated in claim 1. For the same reasons articulated under item 7, the applicant’s arguments regarding the rejection of claim 10 are also moot.
Claim 11 includes similar amended subject matter articulated in claim 1. For the same reasons articulated under item 7, the applicant’s arguments regarding the rejection of claim 11 are also moot. For the same reasons articulated under item 7, the applicant’s arguments regarding the rejection of claim 11 and 12, which depend on claim 11 are also moot.
Claim 14 includes similar amended subject matter articulated in claim 10. For the same reasons articulated under item 7, the applicant’s arguments regarding the rejection of claim 14 are also moot. For the same reasons articulated under item 7, the applicant’s arguments regarding the rejection of claim 15, which depend on claim 15 are also moot.
Conclusion
THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to CAL EUSTAQUIO whose telephone number is (571)270-7229. The examiner can normally be reached on 8am-5pm. If attempts to reach the examiner by telephone are unsuccessful, the examiner's supervisor, Brian Zimmerman, can be reached at (571) 272-3059. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of an application may be obtained from the Patent Application lnformation Retrieval (PAIR) system. Status information for published applications may be obtained from either Private PAIR or Public PAIR. Status information for unpublished applications is available through Private PAlR only. For more information about the PAlR system, see http:/lpair-direct.uspto.gov. Should you have questions on access to the Private PAlR system, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative or access to the automated information system, call 800-786-91 99 (IN USA OR CANADA) or 571-272-1000.
/CAL J EUSTAQUIO/Examiner, Art Unit 2686
/BRIAN A ZIMMERMAN/Supervisory Patent Examiner, Art Unit 2686
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