Trials@uspto.gov
`571-272-7822
`
`Paper No. 9
`Date: April 13, 2020
`
`UNITED STATES PATENT AND TRADEMARK OFFICE
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`
`MOTOROLA MOBILITY LLC,
`Petitioner,
`v.
`UNILOC 2017 LLC,
`Patent Owner.
`
`Case IPR2020-00038
`Patent 6,868,079 B1
`
`
`
`
`
`
`
`
`
`Before SALLY C. MEDLEY, JEFFREY S. SMITH, and GARTH D. BAER,
`Administrative Patent Judges.
`MEDLEY, Administrative Patent Judge.
`
`DECISION
`Granting Institution of Inter Partes Review
`35 U.S.C. § 314
`
`
`
`
`
`
`
`

`

`IPR2020-00038
`Patent 6,868,079 B1
`
`INTRODUCTION
`I.
`Motorola Mobility LLC (“Petitioner”) filed a Petition for inter partes
`review of claim 17 of U.S. Patent No. 6,868,079 B1 (Ex. 1001, “the
`’079 patent”). Paper 2 (“Pet.”).1 Uniloc 2017 LLC (“Patent Owner”) filed a
`Preliminary Response. Paper 6 (“Prelim. Resp.”). Institution of an inter
`partes review is authorized by statute when “the information presented in the
`petition . . . and any response . . . shows that there is a reasonable likelihood
`that the petitioner would prevail with respect to at least 1 of the claims
`challenged in the petition.” 35 U.S.C. § 314(a) (2012). Upon consideration
`of the Petition and Preliminary Response, we conclude the information
`presented shows that there is a reasonable likelihood that Petitioner would
`prevail in showing the unpatentability of the challenged claim.
`A. Related Matters
`Petitioner and Patent Owner indicate that the ’079 patent is the subject
`of several court proceedings, as well as inter partes review proceeding
`IPR2019-00510 (“IPR510”). Pet. 2–3; Prelim. Resp. 6–7. The ’079 patent
`also is the subject of IPR2020-00420, for which a decision whether to
`institute inter partes review has not yet been rendered.2
`B. The ’079 Patent
`The ’079 patent describes “a method of operating a radio
`communication system,” where the radio communication system is “required
`to be able to exchange [signaling] messages between a Mobile Station (MS)
`
`
`1 Petitioner identifies Motorola Mobility LLC, Motorola Mobility Holding
`LLC, and Lenovo Group Limited as real parties-in-interest. Pet. 2.
`2 Neither party notified the Board of the IPR2020-00420 proceeding. The
`parties are reminded that within 21 days of a change of information listed in
`mandatory notices, they must update such information. 37 C.F.R. § 42.8.
`
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`IPR2020-00038
`Patent 6,868,079 B1
`and a Base Station (BS).” Ex. 1001, 1:7–8, 1:18–20. The ’079 patent
`further describes that an object of the invention “is to improve the efficiency
`of the method by which a MS requests resources from a BS.” Id. at 1:56–58.
`The ’079 patent describes a secondary station (i.e., MS) transmitting a
`request for resources to a primary station (i.e., BS) in a time slot allocated to
`the secondary station, where the secondary station re-transmits the request in
`at least a majority of its allocated time slots until an acknowledgment is
`received from the primary station. Id. at 1:60–67. Because there is no
`possibility of requests from different secondary stations colliding, a
`secondary station can retransmit requests in each allocated time slot. Id. at
`2:3–5. Further, the primary station can improve the accuracy with which it
`determines whether a request was sent by a particular secondary station if
`the received signal strength is close to the detection threshold by examining
`the received signals in multiple time slots allocated to the secondary station
`in question. Id. at 2:9–14.
`An example of a radio communication system is illustrated in Figure
`1, reproduced below.
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`IPR2020-00038
`Patent 6,868,079 B1
`
`
`Figure 1 is a block diagram of a radio communication system comprising a
`primary station (BS) 100 and a plurality of secondary stations (MS 110). Id.
`at 3:10–12. Communication from BS 100 to MS 110 takes place on a
`downlink channel 122, while communication from MS 110 to BS 100 takes
`place on an uplink channel 124. Id. at 3:19–21.
`C. Illustrative Claim
`Petitioner challenges independent claim 17 of the ’079 patent. Claim
`17 is reproduced below.
`17. A method of operating a radio communication
`system, comprising:
`allocating respective time slots in an uplink channel to a
`plurality of respective secondary stations; and
`transmitting a respective request for services to establish
`required services from at least one of the plurality of respective
`secondary stations to a primary station in the respective time
`slots;
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`IPR2020-00038
`Patent 6,868,079 B1
`wherein the at least one of the plurality of respective
`secondary stations re-transmits the same respective request in
`consecutive allocated time slots without waiting for an
`acknowledgement until said acknowledgement is received from
`the primary station,
`wherein the primary station determines whether a request
`for services has been transmitted by the at least one of the
`plurality of respective secondary stations by determining
`whether a signal strength of the respective transmitted request of
`the at least one of the plurality of respective secondary stations
`exceeds a threshold value.
`Ex. 1001, 8:12–33.
`D. Asserted Grounds of Unpatentability
`Petitioner asserts that claim 17 would have been unpatentable on the
`following grounds:
`Claim Challenged
`17
`
`35 U.S.C. §
`103(a)3
`
`References
`Merakos4 (via incorporation-by-
`reference of Kay5), Alamouti6
`Merakos (via incorporation-by-
`reference of Kay), Borth7
`
`17
`
`
`
`103(a)
`
`
`3 The Leahy-Smith America Invents Act, Pub. L. No. 112-29, 125 Stat. 284
`(2011) (“AIA”), amended 35 U.S.C. §§ 102 and 103. Because the ’079
`patent has an effective filing date before the effective date of the applicable
`AIA amendments, we refer to the pre-AIA versions of 35 U.S.C. §§ 102 and
`103.
`4 US 5,521,925, issued May 28, 1996 (Ex. 1003, “Merakos”).
`5 US 5,299,198, issued Mar. 29, 1994 (Ex. 1004, “Kay”).
`6 US 5,933,421, issued Aug. 3, 1999 (Ex. 1006, “Alamouti”).
`7 US 4,829,543, issued May 9, 1989 (Ex. 1005, “Borth”).
`
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`IPR2020-00038
`Patent 6,868,079 B1
`
`II. DISCUSSION
`A. 35 U.S.C. § 314(a) and 35 U.S.C. § 325(d) Contentions
`Patent Owner argues that the factors presented in General Plastic Co. v.
`Canon Kabushiki Kaisha, IPR2016-01357, Paper 19 (PTAB Sept. 6, 2017)
`(precedential as to Section II.B.4.i), “militate in favor of the Board
`exercising its discretion under 35 U.S.C. 314(a) and 37 C.F.R. 42.108(a) to
`deny institution.” Prelim. Resp. 10. Patent Owner also argues that the
`factors presented in Becton-Dickinson and Co. v. B. Braun Melsungen AG,
`IPR2017-01586, Paper 8 at 17–18 (PTAB Dec. 17, 2017) (precedential as to
`§ III.C.5, first paragraph), weigh against institution under 35 U.S.C. § 325(d)
`due to the cumulative nature of the art previously before the Office and
`because “the Petition is cumulative of the grounds presented in the earlier
`IPR.” Id. at 7–9, 14.
`1. 35 U.S.C. § 314(a)
`Institution of an inter partes review may be denied as a matter of
`discretion. See 35 U.S.C. § 314(a). General Plastic sets forth seven factors
`for us to consider when determining whether to exercise that discretion.
`Under the first factor, we consider whether the same petitioner previously
`filed a petition directed to the same claims of the same patent. When
`different petitioners challenge the same claims of the same patent, we also
`consider the nature of any relationship between those petitioners when
`weighing the General Plastic factors. Valve Corporation v. Electronic
`Scripting Products, Inc., IPR2019-00062, Paper 11 at 9 (PTAB Apr. 2,
`2019) (precedential). In particular, in Valve, the first and second
`petitioners (HTC and Valve) were co-defendants in litigation and accused
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`Patent 6,868,079 B1
`of infringing the same patent based on “HTC’s . . . devices that
`incorporate technology licensed from Valve.” Valve, Paper 11, at 10.
`The petition in IPR510 was collectively filed by Apple Inc., LG
`Electronics Inc., Samsung Electronics Co., Ltd., and Samsung Electronics
`America, Inc. (“First Petitioners”). IPR2019-00510, Paper 2, 1. Patent
`Owner does not argue, nor do we find, there to be any relationship between
`the First Petitioners and Petitioner insofar as this and the IPR510 proceeding
`are concerned. According to the record before us, Petitioner (Motorola
`Mobility LLC) was sued for patent infringement of the involved patent
`nearly eight months after Patent Owner filed suits against the First
`Petitioners. Pet. 6; Prelim. Resp. 6–7. Although one of the same claims
`challenged here is challenged in IPR510, factor one weighs against
`discretionary denial because here there is no apparent relationship between
`the First Petitioners and Petitioner such that Petitioner is “similarly situated”
`with any of the First Petitioners as in Valve.
`Under General Plastic factor two, we consider whether, at the time of
`filing of the first petition, the petitioner knew of the prior art asserted in the
`second petition or should have known of it. General Plastic, Paper 19, at
`16. Petitioner argues that, at the time the first petition was filed,
`Petitioner was not aware of any of the three prior art references asserted in
`the Petition. Pet. 6. Petitioner further contends that it was not aware (or
`should have known) of the references, because the suit against it had just
`been filed fewer than two months prior to the filing of the first petition.
`Id. Patent Owner makes no arguments regarding the second factor.
`Based on the record before us, Petitioner’s assertions are reasonable.
`Accordingly, factor two weighs against discretionary denial.
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`The third factor of General Plastic is whether, at the time of filing of
`the second petition, the petitioner had already received the patent owner’s
`preliminary response to the first petition or received the Board’s decision on
`whether to institute review in the first petition. General Plastic, Paper 19,
`at 16. Patent Owner correctly points out that the Petition was filed after the
`Patent Owner Preliminary Response was filed and the Institution Decision
`issued in IPR510. Prelim. Resp. 11–12. Patent Owner, however, does not
`identify any portion of the Petition that may have been tailored in response
`to receiving either the Patent Owner Preliminary Response or the Institution
`Decision. The challenges in the first petition in IPR510 are different from
`the ones in the Petition, with no overlapping prior art. We find, and Patent
`Owner does not show otherwise, that Petitioner gained no advantage from
`having received either the Patent Owner Preliminary Response or the
`Institution Decision. In addition, Petitioner was sued for infringement of the
`’079 patent eight months after the First Petitioners were sued, leading to the
`time lapse between the filing of the first petition and the instant Petition.
`Pet. 6. For all of these reasons, factor three weighs against discretionary
`denial.
`General Plastic factors four and five pertain to “the length of time that
`elapsed between the time the petitioner learned of the prior art asserted in the
`second petition and the filing of the second petition” and “whether the
`petitioner provides adequate explanation for the time elapsed between the
`filings of multiple petitions directed to the same claims of the same patent.”
`Gen. Plastic, Paper 19, at 16. Patent Owner argues that although
`Petitioner discloses when it became aware of the Merakos reference,
`Petitioner fails to disclose when it became aware of the Kay reference.
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`Prelim. Resp. 12. Petitioner, however, explains “Kay is incorporated by
`reference into the Merakos disclosure” such that “the entire disclosure of
`Kay can be considered part of Merakos in the form of a single reference for
`the purposes of invalidity.” Pet. 32 (citing Ex. 1003, 1:9–13). Thus, we do
`not agree with Patent Owner that Petitioner failed to identify when it became
`aware of Kay. Because Petitioner identifies when it became aware of
`Merakos, it follows that that is when Petitioner also became aware of Kay.
`Patent Owner also argues that Petitioner does not explain when it became
`aware of the Borth reference, a reference allegedly assigned to Petitioner.
`Prelim. Resp. 12–13. There is no indication in the record, however, that
`Petitioner (Motorola Mobility LLC) knew about either Kay or Borth
`(assigned to Motorola Inc.) or could have found those references quickly.
`Factor four weighs against discretionary denial.
`As to factor five, Petitioner argues that although approximately nine
`months elapsed between the filing of the first petition and the instant
`Petition, such lapse in time is excusable, because (1) Patent Owner filed its
`suit against Petitioner approximately nine months after it filed suits against
`the First Petitioners, and (2) Petitioner became aware of the primary
`reference, Merakos, four months prior to filing the Petition. Pet. 7. For
`factor five, Patent Owner repeats its arguments presented for factor four,
`which we have addressed. Prelim. Resp. 13. Petitioner’s assertions as to
`factor five are reasonable. Factor five weighs against discretionary denial.
`Under the sixth and seventh General Plastic factors, we consider “the
`finite resources of the Board” and “the requirement under 35 U.S.C.
`§ 316(a)(11) to issue a final determination not later than 1 year after the date
`on which the Director notices institution of review.” General Plastic, Paper
`19, at 16. Patent Owner argues that we should not apply our resources
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`where “Petitioner has not identified any manner in which the asserted
`references differ from the asserted references in a prior petition challenging
`the same claim, and where the Petitioner has not identified when it became
`aware of one of the key references.” Prelim. Resp. 13. As explained above,
`we do not agree that Petitioner did not identify when it became aware of
`Kay. Moreover, Patent Owner does not explain sufficiently why Petitioner’s
`alleged failure to identify the manner in which the asserted references differ
`from the asserted references in the first petition matters insofar as the
`Board’s finite resources are concerned. Here, we determine that any burden
`on the Board of reviewing a second Petition challenging a patent previously
`challenged on different art is outweighed by Petitioner’s desire to challenge
`Patent Owner’s patent before the Board using what it believes is the best
`prior art, in response to Patent Owner’s lawsuit against Petitioner for patent
`infringement. Petitioner challenges one claim based on two similar grounds,
`which we find would not be burdensome for us to consider. Lastly, there is
`no issue before us, or presented by either party, that would compromise our
`ability to issue a final determination not later than one year after notice of
`institution of review. Accordingly, factors six and seven weigh against
`discretionary denial.
`In summary, the record before us weighs against exercising our
`discretion under § 314(a) to deny institution.
`2. 35 U.S.C. § 325(d)
`Under 35 U.S.C. § 325(d), “the Director may take into account
`whether . . . the same or substantially the same prior art or arguments were
`previously presented to the Office.” In evaluating whether to exercise our
`discretion under § 325(d), we weigh the following non-exclusive factors: (a)
`the similarities and material differences between the asserted art and the
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`IPR2020-00038
`Patent 6,868,079 B1
`prior art involved during examination; (b) the cumulative nature of the
`asserted art and the prior art evaluated during examination; (c) the extent to
`which the asserted art was evaluated during examination, including whether
`the prior art was the basis for rejection; (d) the extent of the overlap between
`the arguments made during examination and the manner in which Petitioner
`relies on the prior art or Patent Owner distinguishes the prior art; (e) whether
`Petitioner has pointed out sufficiently how the Examiner erred in its
`evaluation of the asserted prior art; and (f) the extent to which additional
`evidence and facts presented in the Petition warrant reconsideration of prior
`art or arguments. Becton Dickinson, at 17–18. “If, after review of factors
`(a), (b), and (d), it is determined that the same or substantially the same art
`or arguments previously were presented to the Office, then factors (c), (e),
`and (f) relate to whether the petitioner has demonstrated a material error by
`the Office.” Advanced Bionics, LLC v. Med-El Electromedizinishe Gerӓte
`GMBH, IPR2019-01469, Paper 6 at 10 (PTAB Feb. 13, 2020) (precedential).
`There is no dispute that none of the references relied upon in the
`Petition were cited or considered during examination. Pet. 5, 9; Prelim.
`Resp. 8–9, 14. There also is no dispute that none of the references relied
`upon in the Petition are the same as those relied upon in IPR510. Id. Patent
`Owner, however, asserts that the references relied upon in the Petition and
`those asserted during examination are cumulative, because the references
`“relate to wireless communications systems.” Prelim. Resp. 9. Merely
`contending that the references asserted during examination and the
`references relied upon in the Petition both relate to the broad category of
`wireless communications systems is not persuasive to show how the prior art
`relied on in the Petition, in the manner Petitioner presents, is cumulative of
`how the art was relied on during prosecution. In similar fashion, Patent
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`Owner also argues that that the “Petition is cumulative of the grounds
`presented in the earlier IPR, and should thus be denied under 35 U.S.C. §
`325(d).” Prelim. Resp. 14. Again, Patent Owner, presents no meaningful
`explanation of how the prior art relied on in the Petition, in the manner
`Petitioner presents, is cumulative of the grounds presented in IPR510.
`Accordingly, we are not persuaded by Patent Owner’s conclusory
`arguments.
`For all of the above reasons, we decline to deny the Petition under
`35 U.S.C. § 325(d).
`
`B. Claim Construction
`In this inter partes review, claims are construed using the same claim
`construction standard that would be used to construe the claims in a civil
`action under 35 U.S.C. § 282(b). 37 C.F.R. § 42.100(b) (2019). The claim
`construction standard includes construing claims in accordance with the
`ordinary and customary meaning of such claims as understood by one of
`ordinary skill in the art and the prosecution history pertaining to the patent.
`See id.; Phillips v. AWH Corp., 415 F.3d 1303, 1312–14 (Fed. Cir. 2005) (en
`banc).
`
`“acknowledgment”
`Claim 17 recites “wherein the at least one of the plurality of respective
`secondary stations re-transmits the same respective request in consecutive
`allocated time slots without waiting for an acknowledgement until said
`acknowledgment is received from the primary station.” Ex. 1001, 8:21–25.
`Petitioner proposes that “acknowledgment” should be construed to mean “a
`message sent from the primary station to the secondary station indicating the
`primary station’s receipt of the secondary station’s request.” Pet. 26–27
`(citing Ex. 1007 ¶ 67). Petitioner contends that the proposed construction is
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`consistent with the claim language, specification, and file history of the ’079
`patent and that the construction is supported by a plain meaning of the term
`“acknowledgment.” Id. (citing Ex. 1001, 2:5–8, 2:23–24, 2:40–47, 3:66–
`4:7, Fig. 3; Ex. 1002; Ex. 1007 ¶ 67; Ex. 1021, 17). At this juncture of the
`proceeding, Patent Owner does not oppose Petitioner’s proposed
`construction. Prelim. Resp. 16–17. For purposes of the Decision, we adopt
`Petitioner’s proposed construction.
`For purposes of this Decision, we need not expressly construe any
`other claim term. See Vivid Techs., Inc. v. Am. Sci. & Eng’g, Inc., 200 F.3d
`795, 803 (Fed. Cir. 1999) (holding that “only those terms need be construed
`that are in controversy, and only to the extent necessary to resolve the
`controversy”); see also Nidec Motor Corp. v. Zhongshan Broad Ocean
`Motor Co., 868 F.3d 1013, 1017 (Fed. Cir. 2017) (citing Vivid Techs. in the
`context of an inter partes review).
`C. Principles of Law
`A patent claim is unpatentable under 35 U.S.C. § 103(a) if the
`differences between the claimed subject matter 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. KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 406
`(2007). The question of obviousness is resolved on the basis of underlying
`factual determinations including: (1) the scope and content of the prior art;
`(2) any differences between the claimed subject matter and the prior art; (3)
`the level of ordinary skill in the art;8 and, (4) when in evidence, objective
`
`8 Relying on the testimony of Dr. Zhi Ding, Petitioner offers an assessment
`as to the level of skill in the art at the time of the ’079 patent. Pet. 25–26
`(citing Ex. 1007 ¶¶ 18–22). Although Patent Owner contests Petitioner’s
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`evidence of nonobviousness. Graham v. John Deere Co., 383 U.S. 1, 17–18
`(1966).
`D. Asserted Obviousness of Claim 17 over Merakos (via Kay) and
`Alamouti, and over Merakos (via Kay) and Borth
`Petitioner contends claim 17 is unpatentable under 35 U.S.C. § 103(a)
`as obvious over (1) Merakos (via Kay) and Alamouti, and (2) Merakos (via
`Kay) and Borth. Pet. 45–72. In support of its showing, Petitioner relies
`upon the declaration of Dr. Ding. Id. (citing Ex. 1007).
`1. Merakos
`Merakos describes a system that integrates data termination
`communications in a cellular telephone communication system. Ex. 1003,
`1:21–23. The system provides a communication protocol, which permits
`integration of data terminal traffic in a digital voice cellular radio
`communication system. Id. at 2:57–60. Data traffic conveyed from remote
`data stations and remote radio telephone stations to a base station is carried
`by the same reverse Time Division Multiple Access (TDMA) frame. Id. at
`2:60–62. Allocation of time slots for voice or data is controlled by the base
`station. Id. at 2:62–64.
`A cellular radio telephone communication system is illustrated in
`Figure 1 reproduced below.
`
`
`assessment, Patent Owner does not propose an alternative assessment.
`Prelim. Resp. 15–16. To the extent necessary, and for purposes of this
`Decision, we accept the assessment offered by Petitioner as it is consistent
`with the ’079 patent and the asserted prior art.
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`
`
`Figure 1 illustrates a cellular radio telephone communication system that
`includes the capability of permitting data stations to communicate over the
`same channel bandwidth as is occupied by telephones. Id. at 4:37–40. A
`base station 11 communicates with voice stations 12, 13, and 14 as well as
`with data stations 16, 17, and 18. Id. at 5:6–8. The mechanism for
`communication is a radio link from the base station that can be tuned by
`each of voice stations 12–14 and data stations 16–18. Id. at 5:8–10. The
`radio frequency carrier linking base station 11 with each of data stations and
`voice stations 12–18 employs a TDMA format, using forward frame 22 and
`reverse frame 23. Id. at 5:20–23. Forward frame 22 consists of a plurality
`of time slots that are divided into control slots carrying control information
`and data slots carrying either digitized voice or digital data for either a voice
`station or a data station. Id. at 5:23–27. Separate from outgoing forward
`frame 22 is a reverse frame 23 of time division multiplex time slots for
`carrying traffic from each of voice stations 12–14 and data stations 16–18 to
`base station 11. Id. at 5:14–17.
`An example reverse channel data frame is illustrated in Figure 3
`reproduced below.
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`
`
`Figure 3 illustrates an example of a reverse channel data frame utilized by
`the cellular radio telephone communication system of Figure 1. Id. at 4:43–
`44. The reverse channel data frame includes six frequencies (i.e., F1–F6)
`and six time slots (i.e., SLOT 1–SLOT 6) for a total of 36 slots. Id. at 6:62–
`65. Control slots are shown as including subslots RR (i.e., reverse response
`subslots) and RA (i.e., reverse allocate subslots). Id. at 6:66–7:7. Control
`slot overhead is shown as subslots C1, C2, C3, and C4 for slot 2 of
`frequency 1, as well as subslots C5, C6, C7, and C8 for slot 6 of frequency
`6. Id. at 7:8–13. Control slot overhead is provided such that allocate
`requests may be initiated at each of the data stations during their pre-
`assigned subslot, where the base station detects the presence of a bit set in
`one of the subslots and recognizes the bit as a reverse channel allocate
`request for a specific data station. Id. at 7:14–19.
`2. Kay
`Kay9 describes a mobile telephone system that provides telephone
`service over radio frequency links to mobile stations. Ex. 1004, 1:16–18.
`
`
`9 Petitioner contends that Kay is incorporated by reference into the Merakos
`disclosure. Pet. 32 (citing Ex. 1003, 1:9–13). Petitioner contends that “the
`entire disclosure of Kay can be considered part of Merakos in the form of a
`single reference for the purposes of invalidity.” Id. At this juncture of the
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`The base station subsystem of the mobile telephone system operates in
`accordance with a TDMA protocol. Id. at 3:35–38. Each base station
`manages a pool of duplex transmission channels, where the pool consists of
`a plurality of different carrier frequencies, each of which are time divided to
`provide a repeating frame consisting of a number of slots. Id. at 3:38–41.
`The pool is divided between forward (i.e., base to mobile) requests and
`reverse (i.e., mobile to base) requests. Id. at 4:5–7.
`An example of a “reverse allocation request/reverse allocation
`acknowledgment/reverse assignment/reverse assignment acknowledgment
`exchange” is illustrated in Figure 20 reproduced below. Id. at 5:49–52.
`
`
`proceeding, Patent Owner does not dispute Petitioner’s assertions that Kay is
`incorporated by reference into the Merakos disclosure or that the entire
`disclosure of Kay can be considered part of Merakos. Prelim. Resp. 12
`(acknowledging that Kay is incorporated by reference in the Merakos
`reference).
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`
`
`Figure 20 illustrates an exchange between a mobile station and a base station
`involving a reverse allocation request, reverse allocation acknowledgment,
`reverse assignment, and reverse assignment acknowledgment. Id. Mobile
`station sends a reverse allocation request message on a reverse allocation
`(i.e., RA) channel to the base station using triple diversity (i.e., time
`diversity, frequency diversity, and power diversity). Id. at 15:16–21, 15:33–
`34. Base station sends a reverse allocation acknowledgment to the mobile
`station on a reverse response (i.e., RR) channel. Id. at 15:34–35. Base
`station subsequently assigns a channel to the mobile station and sends a
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`IPR2020-00038
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`reverse assignment to the mobile station on a forward control (i.e., FC)
`channel. Id. at 15:21–23, 15:38–39. Mobile station subsequently sends a
`reverse assignment acknowledgment to the base station on the RR channel.
`Id. at 15:39–41.
`
`3. Alamouti
`Alamouti describes a wireless communication system that combines
`time division duplex (i.e., TDD), frequency division duplex (i.e., FDD),
`TDMA, and orthogonal frequency division multiplexing (i.e., OFDM), to
`enable a base station to efficiently communicate with many remote stations.
`Ex. 1006, 5:12–17. A communication receiver of the wireless
`communication system uses both frequency diversity and polarization
`diversity as communication techniques, where polarization diversity is the
`use of uncorrelated horizontal and vertical polarization paths between a
`remote station and a base station, and frequency diversity transmits
`information on more than one carrier frequency. Id. at 26:60–29:2.
`Alamouti describes time diversity and diversity reception, in the form of, for
`example, scanning received signals “until one is found to be above a
`predetermined threshold.” Id. at 27:13–17, 27:26–28.
`4. Borth
`Borth describes a TDMA radio system receiver that utilizes a
`synchronizing sequence contained within an assigned timeslot of message
`data to adapt a multi-phase demodulator to the finite impulse response of the
`radio channel during the assigned timeslot. Ex. 1005, 2:20–25. First and
`second phases of the synchronizing sequence are correlated to a
`predetermined sequence to create first and second correlator signals. Id. at
`2:25–31. The first and second correlator signals are then correlated with
`first and second phases of received message data and the resulting outputs of
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`IPR2020-00038
`Patent 6,868,079 B1
`correlation are combined to yield first and second phase data. Id. at 2:31–
`35.
`
`An example TDMA receiver is illustrated in Figures 2A and 2B
`(reproduced from Petitioner’s Petition, including modifications made by
`Petitioner) reproduced below.
`
`
`
`Figures 2A and 2B are, together, a block diagram of a TDMA receiver. Id.
`at 2:41–42. Digital signal outputs of A/D converters 209 and 211,
`respectively, are applied to in-phase (I) time slot correlator 213 and
`quadrature (Q) correlator 215, respectively, as well as to their respective
`signal buffers 217 and 219. Id. at 3:30–34. I correlator 213 performs a
`correlation function between all received bits of the input signal and a pre-
`loaded synchronization word (i.e., I sync word) corresponding to the in-
`phase time slot sync word. Id. at 3:34–37. In the same way, Q correlator
`215 performs a correlation function between the pre-stored quadrature Q
`synch word from memory 221 and the sampled quadrature input. Id. at
`3:43–46. Outputs of correlators 213 and 215 are applied to squaring blocks
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`223 and 225, respectively. Id. at 3:47–48. Squaring block outputs are then
`applied to summing block 227, where I and Q correlation signals are
`summed together to form a squared envelope signal representing the sum of
`squares of the correlation signal. Id. at 3:51–55. The output of summing
`block 227 is then routed to time slot detector 229, where the summed
`correlation signal is compared with a predetermined threshold value
`representing a minimum allowable correlation value, which would represent
`a detected timeslot. Id. at 3:61–66. If the summed output is greater than the
`threshold value, a time slot detect signal is generated and applied to system
`timing controller 231. Id. at 3:66–68. Timing controller 231 functions as a
`phase-locked loop, using a stable timing reference to validate the timeslot
`detect signal and provide a validated detect output signal, where the
`validated detect output signal is combined with a bit clock output and then
`routed to I and Q signal buffers 217 and 219, respectively. Id. at 4:1–9.
`5. Discussion
`Merakos (incorporating Kay) and Alamouti
`Claim 17 recites “[a] method of operating a radio communication
`system, comprising.” Petitioner contends that to the extent the preamble is
`limiting, Merakos describes remote data stations 16–18 communicating with
`a base station BS 11 using a radio link, and that a person having ordinary
`skill in the art would have understood that exchanging data between the base
`station and mobile stations constitutes operating a radio communication
`system. Pet. 45–46 (citing Ex. 1003, code (57), 2:47–56, 5:4–10, Fig. 1;
`Ex. 1007 ¶¶ 122–123).
`Claim 17 further recites “allocating respective time slots in an uplink
`channel to a plurality of respective secondary stations.” Petitioner contends
`that Merakos teaches a reverse frame that includes pre-assigned control
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`IPR2020-00038
`P