T 0702/11 (WiMAX analyzer/INNOWIRELESS) of 5.9.2014

European Case Law Identifier: ECLI:EP:BA:2014:T070211.20140905
Date of decision: 05 September 2014
Case number: T 0702/11
Application number: 07008228.4
IPC class: H04B 7/26
H04J 3/06
Language of proceedings: EN
Distribution: D
Download and more information:
Decision text in EN (PDF, 391.746K)
Documentation of the appeal procedure can be found in the Register
Bibliographic information is available in: EN
Versions: Unpublished
Title of application: Time synchronizing apparatus for mobile WiMAX analyzer
Applicant name: Innowireless Co., Ltd.
Opponent name: -
Board: 3.5.03
Headnote: -
Relevant legal provisions:
European Patent Convention Art 56
Rules of procedure of the Boards of Appeal Art 12(4)
Rules of procedure of the Boards of Appeal Art 13(1)
Keywords: Inventive step (main request, auxiliary requests 1 to 3)
Inventive step - no
Late-filed auxiliary requests (auxiliary requests 4 and 5)
Late-filed auxiliary requests - not admitted
Catchwords:

-

Cited decisions:
-
Citing decisions:
-

Summary of Facts and Submissions

I. This appeal is against the decision of the examining division refusing European patent application No. 07008228.4 on the ground that the subject-matter of claims 1 of a main request and an auxiliary request lacked an inventive step (Article 56 EPC).

II. With the statement of grounds of appeal the appellant filed sets of claims of a main request and auxiliary requests 1 and 2.

III. In a communication accompanying the summons to oral proceedings, the board gave a preliminary opinion as regards inventive step in respect of the subject-matter of claim 1 of each request (Article 56 EPC), referring to the following documents:

D1: US 5,757,786 A1;

D4: Fluke 910/910R GPS Controlled Frequency Standards, Technical Data, January 2003; and

D5: A. Haug, "Digitale Methoden der Phasenmessung", Elektrotechnische Zeitschrift, Ausgabe B, June 1973, VDE Verlag GmbH, Berlin, Germany, pages 267-270.

IV. In response to the board's communication, the appellant filed with a letter dated 22 August 2014 additional sets of claims as auxiliary requests 3 and 4.

V. Oral proceedings before the board were held on 5 September 2014.

In the course of the oral proceedings the appellant replaced auxiliary request 4 on file by a modified version and submitted a further set of claims as auxiliary request 5.

The appellant requested that the decision under appeal be set aside and that a patent be granted on the basis of claims of the main request or, in the alternative, of auxiliary request 1 or 2, all filed together with the statement of grounds of appeal, or on the basis of claims of auxiliary request 3 as filed with the letter dated 22 August 2014, or on the basis of claims of auxiliary request 4 or 5 as submitted during the oral proceedings.

At the end of the oral proceedings, after deliberation, the chairman announced the board's decision.

VI. Claim 1 of the main request reads as follows:

"A mobile WiMAX analyzer configured to maintain time synchronization between a plurality of mobile WiMAX analyzers, characterized by

a time synchronizing apparatus comprising:

a GPS receiver (110, 210, 310) for outputting a GPS signal that is synchronized with GPS time using information received from a GPS satellite; and

a synchronization control unit (120, 200, 320) for comparing the GPS signal, which is received from the GPS receiver (110, 210, 310), and a reference signal, which is generated using an internal clock, and controlling synchronization according to the result of the comparison, wherein

the synchronization control unit (120, 220, 320) comprises:

an oscillator (123) for outputting an oscillation signal having a predetermined frequency, which is used as an internal clock source;

a divider (124) for dividing the oscillation signal, which is output from the oscillator (123), into the reference signal, which has a frequency lower than that of the oscillation signal;

an offset comparison unit (122) for comparing differences between the GPS signal, which is received from the GPS receiver (110, 210, 310), and the reference signal, which is generated by the divider (124), and outputting a result value of the comparison; and

a processor (121) for controlling an oscillation frequency of the oscillator (123) until the result value output from the offset comparison unit satisfies a predetermined reference value, wherein

each of the GPS signal and the reference signal is a 1PPS signal, and

when the GPS signal or the reference signal is received, the offset comparison unit (122), starts counting based on the oscillation signal output from the oscillator (123), latches a count number reached until the GPS signal or the reference signal is received again, and then outputs the count number as the result value."

Claim 1 of auxiliary request 1 differs from claim 1 of the main request in that in the sixth paragraph the wording "an oscillator (123)" has been replaced by "an oven controlled crystal oscillator, OCXO, (123) having a temperature compensation function" and in that the wording "oven controlled crystal" has been inserted before "oscillator" in both the seventh and the ninth paragraph.

Claim 1 of auxiliary request 2 differs from claim 1 of the main request in that the following feature has been added:

"the mobile WiMAX analyzer further comprising:

a LED display unit (125) for visually displaying a stabilized state of the synchronization, wherein

the processor (121) causes the LED display unit (125) to be turned on when the reference value is satisfied".

Claim 1 of auxiliary request 3 differs from claim 1 of auxiliary request 2 in that the wording "each of the GPS signal and the reference signal is a 1PPS signal, and" has been deleted, and in that the following feature has been inserted in the first paragraph between "mobile WiMAX analyzers," and "characterized by":

"each of which is provided with a handover function and is capable of carrying out handover tests for mobile WiMAX terminals, wherein the term 'handover' refers to a process in which a mobile WiMAX terminal moves from a radio access station that provides a wireless interface to another radio access station with a handover being performed when the radio access station to which the mobile WiMAX terminal is connected is to be changed in order to provide a higher-quality signal, or performed when the mobile WiMAX terminal can receive higher Quality of Service (QoS) from another radio access station;".

Claim 1 of auxiliary request 4 reads as follows:

"Use of mobile WiMax analyzers in a handover test system, each mobile WiMAX analyzer configured to maintain time synchronization between a plurality of mobile WiMAX analyzers, each of which is provided with a handover function and is capable of carrying out handover tests for mobile WiMAX terminals, wherein the term 'handover' refers to a process in which a mobile WiMAX terminal moves from a radio access station that provides a wireless interface to another radio access station with a handover being performed when the radio access station to which the mobile WiMAX terminal is connected is to be changed in order to provide a higher-quality signal, or performed when the mobile WiMAX terminal can receive higher Quality of Service (QoS) from another radio access station;

each mobile WiMAX analyzer characterized by

a time synchronizing apparatus comprising:

a GPS receiver (110, 210, 310) for outputting a GPS signal that is synchronized with GPS time using information received from a GPS satellite; and

a synchronization control unit (120, 200, 320) for comparing the GPS signal, which is received from the GPS receiver (110, 210, 310), and a reference signal, which is generated using an internal clock, and controlling synchronization according to the result of the comparison, wherein

the synchronization control unit (120, 220, 320) comprises:

an oscillator (123) for outputting an oscillation signal having a predetermined frequency, which is used as an internal clock source;

a divider (124) for dividing the oscillation signal, which is output from the oscillator (123), into the reference signal, which has a frequency lower than that of the oscillation signal;

an offset comparison unit (122) for comparing differences between the GPS signal, which is received from the GPS receiver (110, 210, 310), and the reference signal, which is generated by the divider (124), and outputting a result value of the comparison; and

a processor (121) for controlling an oscillation frequency of the oscillator (123) until the result value output from the offset comparison unit satisfies a predetermined reference value,

wherein

when the GPS signal or the reference signal is received, the offset comparison unit (122) starts counting based on the oscillation signal output from the oscillator (123), latches a count number reached until the GPS signal or the reference signal is received again, and then outputs the count number as the result value, the mobile WiMAX analyzer further comprising:

a LED display unit (125) for visually displaying a stabilized state of the synchronization, wherein

the processor (121) causes the LED display unit (125) to be turned on when the reference value is satisfied,

wherein the WiMAX analyzers (100, 200) are synchronized using the time synchronizing apparatuses, wherein channels are formed between the WiMAX analyzers (100, 200) and a portable subscriber station, PSS, in a wireless environment,

a control host (400) functions to control a test process and determine whether tests are passed, the control host (400) being connected with the analyzers and the portable subscriber station thus monitoring the conditions of the portable subscriber station,

the time synchronizing apparatuses of the mobile WiMAX analyzers being provided with some of the functions performed by individual radio access stations, so that time synchronization between mobile WiMAX analyzers capable of carrying out handover tests for mobile WiMAX terminals can be maintained."

Claim 1 of auxiliary request 5 differs from claim 1 of the main request in that the following features have been added:

"wherein a synchronization scheme between the mobile WiMAX analyzers is configured such that a clock signal used by a first one (MRSS1) of the mobile WiMAX analyzers is directly provided to a second one (MRSS2) of the mobile WiMAX analyzers and is used as a clock signal for the second WiMAX analyzer (MRSS2), wherein each of the mobile WiMAX analyzers is provided with a terminal for outputting a reference clock signal, which is internally used, to the outside, and a terminal for receiving a clock signal from the outside, wherein, using the terminals, the first mobile WiMAX analyzer (MRSS1) functions as a master analyzer for providing the clock signal, which is internally used, as the reference signal, and the second WiMAX analyzer (MRSS2) adjacent to the master analyzer functioning as a slave analyzer for receiving the clock signal provided from the master analyzer".

Reasons for the Decision

1. Claim 1 of the main request - inventive step

(Article 56 EPC)

1.1 Claim 1 of the main request relates to a mobile WiMAX analyzer which is characterized by features relating to a time synchronizing apparatus. The board considers D1, which relates to a time synchronization apparatus for use in, inter alia, a digital mobile communication station, as representing the pertinent prior art and, hence, a suitable starting point for assessing inventive step. More specifically, D1 discloses a time synchronization apparatus (cf. the abstract and Figure 1) which includes a GPS receiver 10 for outputting a GPS 1PPS signal which is synchronized with GPS time. The time synchronization apparatus includes a synchronization control unit for controlling synchronization between a locally generated 1PPS signal and the GPS 1PPS signal. The synchronization control unit includes an oscillator 30 (see Figure 1) having a predetermined frequency of 10 MHz (see the connection from oscillator 30 to second controller 80 in Figure 1). The synchronization control unit further includes a counter 40 which divides the 10 MHz output of the oscillator in order to achieve a 1PPS signal, i.e. a signal having a pulse repetition frequency of 1 Hz. Hence, the counter operates as a divider for dividing the oscillation signal of the oscillator 30 in order to achieve a reference signal which has a frequency lower than that of the oscillation signal.

The synchronization control circuit further includes a comparator 50 for comparing the GPS 1PPS signal with the locally generated 1PPS signal and for establishing a phase difference signal at its output. The comparator 50 is disclosed in more detail in column 3, lines 14 to 21, and in Figure 3, in which a gate controller 3 is understood by the board to operate such that it generates a binary signal which enables an AND gate 2 during a time period between the arrivals of the GPS 1PPS and the locally generated 1PPS signals at its inputs, during which period the AND gate 2 outputs a pulse train. The number of pulses of the pulse train is therefore a measure for the phase difference between the GPP 1PPS signal and the locally generated 1PPS signal. This implies that the pulses of the pulse train are counted for the purpose of outputting the phase difference signal.

The board notes that this understanding is also in conformity with the common general knowledge in the field of digital phase difference measurement, as is apparent from e.g. D5; see, in particular, Figure 2a) which shows an offset comparison circuit and the third and fourth diagrams of Figure 2b) which show the operation of the offset comparison circuit as regards the detection of a phase offset between two input signals.

The synchronization control unit of D1 further includes a processor 20 for controlling, via D/A-converter 90, the frequency of the oscillator 30.

1.2 The appellant argued that the subject-matter of claim 1 differs from the apparatus of D1 as follows:

(a) D1 is not a suitable starting point for assessing inventive step, since the invention relates to a specific device, namely a WiMAX analyzer which is to be used in a specific mobile network environment, whereas D1 discloses a general purpose time synchronization apparatus which is not specifically provided for WiMAX technology;

(b) Claim 1 seeks protection for a mobile WiMAX analyzer. D1, however, does not disclose an analyzer but a time synchronization apparatus;

(c) D1 does not disclose a "divider";

(d) D1 does not disclose a "predetermined reference value" to be satisfied by the result value output from the offset comparison unit. In Figure 2 of D1, a phase error is corrected only in response to an average of the results of a large number of phase comparisons. In particular, in D1 the phase error is not corrected until the result value of a single comparison satisfies a predetermined reference value; and

(e) D5 does not represent common general knowledge in the field of WiMAX analyzers.

1.3 The board does not find arguments (a) and (c) to (e) convincing:

Re (a): The WiMAX analyzer of claim 1 is specified solely by features relating to a time synchronizing apparatus. There is no feature in claim 1 which implies that the time synchronization requires any specific adaptation for use in analysis in a WiMAX environment. Therefore, the board considers it appropriate to start out from D1 as representing the closest prior art for assessing inventive step of the claimed subject-matter. The board notes that D1 even explicitly mentions applications in telecommunications as a useful application of the time synchronization apparatus ("The present invention provides precise timing information having an error within 100 ns using the GPS satellite and therefore it has useful applications to systems, such as the integrated information network, the digital mobile communication station and the satellite communication network station", see D1, column 3, line 65 to column 4, line 3).

Re (c): The expression "divider" is a functional term of generic nature which implies a specific result to be achieved, i.e. in the present case an oscillator signal having a frequency which is a particular division of the original frequency. The counter 40 as referred to above (see point 1.1) is a specific implementation of a divider.

Re (d): The expression "until the result value output from the offset comparison unit satisfies a predetermined reference value" defines a result to be achieved by the processor, i.e. the oscillator is controlled such that it oscillates at the desired frequency. The same control is, however, used in D1, see column 2, lines 52 to 55 ("The microprocessor unit 20 ... computes the frequency error value.") and lines 62 to 67 ("In addition, the microprocessor unit 20 converts the computed frequency error to the analog value through the digital/analog converter 90 and provides the converted signals to the control signals of the oscillator 30 for precisely controlling the oscillating frequency of the oscillator 30."). According to these passages of D1, it is not mandatory that the results of a number of comparisons are averaged, and claim 1 of D1 is drafted accordingly.

Re (e): The appellant did not contest that D5 represented common general knowledge in the field of phase difference measurement. It was, however, in this context that the board referred to this document (cf. point 1.1 above).

1.4 The subject-matter of claim 1 thus differs from the time synchronization apparatus of D1 in that the time synchronizing apparatus is part of a WiMAX analyzer.

The objective technical problem starting out from D1 was formulated by the appellant as being to adapt the teaching of D1 to a specific communication network. The board considers this an appropriate formulation of the technical problem when starting out from D1.

1.5 The skilled person seeking a solution for this problem would be led by the above-cited passage of D1 at column 3, line 65, to column 4, line 3, to include the known time synchronization apparatus in components of an information network or a mobile communication network station which require precise and synchronized time information. In WiMAX technology a precise synchronization of radio access stations is mandatory for maintaining an acceptable system performance during a handover of a communication between radio access stations. This requirement was well-known in the art, see paragraphs [0005] and [0006] of the present application as published. Therefore, the skilled person would, without exercising inventive skill, provide the time synchronization apparatus of D1 at each radio access station having a handover function. Since a radio access station commonly includes test and analysis functionality in addition to its normal operation as a radio interface to mobile stations, it would have been obvious to the skilled person to use the known time synchronization apparatus also in supporting test and analysis functions of the radio base station, once these test and analysis functions require precise time information.

Hence, the skilled person, starting out from D1 and taking into account the common general knowledge, would have arrived at the subject-matter of claim 1 without the exercise of inventive skill.

1.6 The appellant argued that the prior art did not hint at including a time synchronization apparatus specifically in a WiMAX analyzer and specifically for the purpose of carrying out handover tests in a WiMAX system.

1.7 The board is not convinced by this argument. Since at the priority date it was known in the art that a handover function in a WiMAX system requires precise time synchronization between radio base stations, it follows that precise time synchronization is also mandatory for an analyzer involved in analyzing handover functions. Therefore, the skilled person would consider taking steps to have precise time synchronization in a radio base station and an analyzer, by including a time synchronization apparatus which itself was known in the art. Therefore, including a known time synchronization apparatus specifically in a WiMAX analyzer would not have required the exercise of inventive skill.

1.8 For the above reasons, the subject-matter of claim 1 of the main request does not involve an inventive step (Articles 52(1) and 56 EPC).

1.9 The main request is therefore not allowable.

2. Claim 1 of auxiliary request 1 - inventive step (Article 56 EPC)

2.1 The additional feature in claim 1 of auxiliary request 1 (see point VI above), i.e. that the oscillator is an oven controlled crystal oscillator (OCXO) having a temperature compensation function, serves to reduce variations in the oscillation frequency of the oscillator which would otherwise be caused by variations in ambient temperature. Hence, the further technical problem related to this additional feature may be seen as improving the thermal stability of the time synchronization apparatus.

2.2 The skilled person seeking a solution for this additional problem would be led by D4 (see Figure 2 and the specifications "910 (GPS-OCXO)" below Figure 3) to use an oven controlled crystal oscillator as a frequency source of the time synchronization apparatus. Therefore, and in addition to the reasons given at point 1 above as regards claim 1 of the main request, the skilled person would have arrived at the subject-matter of claim 1 of auxiliary request 1 without the exercise of inventive skill.

2.3 The appellant argued that the additional feature in claim 1 provided two separate mechanisms for frequency stabilization, one being the oven control and the other being the temperature compensation function. D4 disclosed only an oven control, but not an additional temperature compensation function.

2.4 The board does not agree. The wording of the feature merely expresses that the provision of an oven control results in an additional temperature compensation function. There is also no indication in the application to support the appellant's submission that the time synchronizing apparatus would include a temperature compensation function other than the oven control.

2.5 The board therefore concludes that the subject-matter of claim 1 of auxiliary request 1 does not involve an inventive step (Articles 52(1) and 56 EPC).

2.6 Auxiliary request 1 is therefore not allowable.

3. Claim 1 of auxiliary request 2 - inventive step (Article 56 EPC)

3.1 The additional features in claim 1 of auxiliary request 2 relate to the provision of an LED display unit for visually displaying a stabilized state of the synchronization, wherein the processor causes the LED display unit to be turned on when the reference value is satisfied. These features thus serve to indicate to the user that the reference signal generated by the time synchronizing apparatus is locked to the received GPS signal.

3.2 The skilled person would however be led by D4 (see the paragraph "LED indicators" at the top of the centre column on the last page) to provide an LED display unit and to control the LED display unit to be turned on when the internally generated frequency is locked to the received GPS signal. For this reason, and in addition to the reasons given at point 1, the skilled person would have arrived at the subject-matter of claim 1 of auxiliary request 2 without the exercise of inventive skill.

3.3 The appellant understood the LED indicator "locked to GPS" in D4 as providing information about whether or not a GPS signal is received at the GPS receiver and, hence, that the indicator would not indicate a state in which the reference signal is in synchronism with the GPS signal.

3.4 This argument is not convincing. There is no disclosure in D4 to the effect that the proper reception of a GPS signal is separately indicated to the user. Further, considering the meaning of the expression "Frequency stability - locked to GPS" in the "910/910R specifications" at page 3, it is clear that the expression "locked to GPS" is used in D4 to indicate that the internal oscillator is locked to the received GPS signal or, more precisely, to the time signal derived from the GPS signal. Hence, the LED indicator in D4 shows that the internal oscillator is locked to the time signal provided by the GPS signal.

3.5 The board therefore concludes that the subject-matter of claim 1 of auxiliary request 2 does not involve an inventive step (Articles 52(1) and 56 EPC).

3.6 Auxiliary request 2 is therefore not allowable.

4. Claim 1 of auxiliary request 3 - inventive step (Article 56 EPC)

4.1 As regards the further features added in the first paragraph of claim 1 of auxiliary request 3 (see point VI above), the appellant argued that a particular kind of stand-alone WiMAX analyzer was thereby defined, namely an analyzer which was able to test a handover function in a WiMAX environment.

4.2 However, in the board's view, claim 1 specifies a WiMAX analyzer only in functional terms and does not limit the claim to a stand-alone analyzer as argued by the appellant. The claim also relates to a conventional WiMAX radio access station in which specific parts are foreseen for carrying out tests on the signal during a handover operation. A WiMAX access radio station having test capabilities was however generally known at the priority date of the application, as was not contested by the appellant.

Furthermore, the deletion of the feature which specified that the GPS signal and the reference signal are a 1PPS signal does not further distinguish the claimed subject-matter from that of claim 1 of auxiliary request 2.

4.3 For these reasons and for those given at point 3 concerning claim 1 of auxiliary request 2, the subject-matter of claim 1 of auxiliary request 3 does not involve an inventive step (Articles 52(1) and 56 EPC).

4.4 Auxiliary request 3 is therefore not allowable.

5. Auxiliary request 4 - admissibility

5.1 The last paragraph of claim 1 of auxiliary request 4 (see point VI) specifies the time synchronizing apparatus as "being provided with some of the functions performed by individual radio access stations". The board notes that functions to be performed by radio access stations during an initial access and handover process are described in paragraphs [0017] and [0018] of the application as published with reference to Figure 2 and include, inter alia, the transmission of a Downlink map, Downlink Channel Descriptor messages and Uplink Channel Descriptor messages, and performance of a synchronization process, a connection parameter acquisition process, and a ranging process. The last feature of claim 1 is prima facie unclear, since it is not apparent which of these various functions of individual radio access stations are provided to the time synchronizing apparatus. Further, none of these functions appears to be specific to the time synchronizing apparatus which, by its very nature, is only able to generate a highly precise time signal.

Consequently, claim 1 prima facie lacks clarity (Article 84 EPC).

5.2 Since auxiliary request 4 was filed late and its claim 1 prima facie lacks clarity, the board, making use of its discretion pursuant to Article 13(1) of the Rules of Procedure of the Boards of Appeal (RPBA) did not admit it into the proceedings.

6. Auxiliary request 5 - admissibility

6.1 Auxiliary request 5 was submitted during the oral proceedings before the board.

6.2 As regards the admissibility of this request, the board notes the following:

The subject-matter claimed hitherto related to a WiMAX analyzer which included a time synchronizing apparatus for synchronizing a local oscillation signal with a received GPS signal. The additional paragraph of claim 1 of auxiliary request 5 (see point VI above) relates to a synchronization scheme between mobile WiMAX analyzers, which is configured such that the clock signal used by one of the WiMAX analyzers is synchronized with the clock output of another WiMAX analyzer and, hence, is not concerned with the synchronisation of a local oscillation signal with a received GPS signal.

Contrary to the appellant's argument that the subject-matter of claim 1 could be expected to have been duly considered during the prior-art search, since it related to the configuration shown in Figure 3, which appeared in a prominent position in the description, the board is of the view that the subject-matter of claim 1, having not been claimed in the previous proceedings, goes beyond what could reasonably be expected to be considered in the prior-art search. The board would thus be forced to carry out a first substantive examination of the claimed subject-matter or to remit the case to the department of first instance for further prosecution.

In the first-instance proceedings, the applicant was aware of the objections as regards patentability at an early stage. The objection that the time synchronizing apparatus as claimed was disclosed in D1 was raised for the first time in the written opinion accompanying the search report, i.e. even before substantive examination had started, and was repeated, by reference, in the first official communication in the examination proceedings and was reiterated in both a subsequent communication and the communication accompanying a summons to oral proceedings before the examining division. However, the applicant choose not to further limit the claim by including features relating to synchronizing the clock signal of a WiMAX analyzer to the clock signal output of another WiMAX analyzer. Rather, it decided to not attend the oral proceedings before the examining division.

As regards the reasons for submitting this request only during the oral proceedings before the board, the appellant argued that it had not attended the oral proceedings before the examination division, since it had expected a patent to be granted on the basis of the application documents then on file. It was therefore considered not expedient to file further requests during the first-instance proceedings. Further, since auxiliary request 4 was not admitted by the board, auxiliary request 5 had been submitted, the subject-matter of which was easy to understand and did not put an undue burden on the board as regards examination of the scope and content of claim 1.

These arguments are not convincing. There is no indication in the file that grant of a patent could reasonably have been expected after the summons to oral proceedings was issued by the examining division. Further, whether or not claim 1 of auxiliary request 5 is easy to understand is not considered decisive in connection with the power of the board to hold inadmissible a request which could have been presented in the first instance proceedings, as referred to in Article 12(4) RPBA.

6.3 Taking the above considerations and the appellant's arguments into account, the board judges that the subject-matter of claim 1 of auxiliary request 5 is such that this request could - and should - have been presented in the first-instance proceedings. Therefore, the board, making use of its discretion pursuant to Article 12(4) RPBA, does not admit auxiliary request 5 into the proceedings.

7. Since, for the reasons set out above, the requests on file are either inadmissible or not allowable, the appeal is to be dismissed.

Order

For these reasons it is decided that:

The appeal is dismissed.

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