Telefonaktiebolaget LM Ericsson (publ)

Patent Trials and Appeals BoardJun 11, 2021

2020001806 (P.T.A.B. Jun. 11, 2021)

UNITED STATES PATENT AND TRADEMARK OFFICE UNITED STATES DEPARTMENT OF COMMERCE United States Patent and Trademark Office Address: COMMISSIONER FOR PATENTS P.O. Box 1450 Alexandria, Virginia 22313-1450 www.uspto.gov APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO. 15/509,001 03/06/2017 Mattias Frenne 3000-596 6316 27820 7590 06/11/2021 WITHROW & TERRANOVA, P.L.L.C. 106 Pinedale Springs Way Cary, NC 27511 EXAMINER CUNNINGHAM, KEVIN M ART UNIT PAPER NUMBER 2461 NOTIFICATION DATE DELIVERY MODE 06/11/2021 ELECTRONIC Please find below and/or attached an Office communication concerning this application or proceeding. The time period for reply, if any, is set in the attached communication. Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the following e-mail address(es): patents@wt-ip.com PTOL-90A (Rev. 04/07) UNITED STATES PATENT AND TRADEMARK OFFICE BEFORE THE PATENT TRIAL AND APPEAL BOARD Ex parte MATTIAS FRENNE, JUNG-FU CHENG, DANIEL LARSSON, HAVISH KOORAPATY, and SOROUR FALAHATI Appeal 2020-001806 Application 15/509,001 Technology Center 2400 Before ALLEN R. MacDONALD, MICHAEL J. ENGLE, and SCOTT RAEVSKY, Administrative Patent Judges. ENGLE, Administrative Patent Judge. DECISION ON APPEAL STATEMENT OF THE CASE Appellant1 appeals under 35 U.S.C. § 134(a) from the Examiner’s rejection of claims 1–7 and 9–15, which are all of the claims pending in the application. We have jurisdiction under 35 U.S.C. § 6(b). We AFFIRM. 1 We use the word “Appellant” to refer to “applicant” as defined in 37 C.F.R. § 1.42(a). Appellant identifies Telefonaktiebolaget LM Ericsson (publ) as the real party in interest. Appeal Br. 2. Appeal 2020-001806 Application 15/509,001 2 TECHNOLOGY The application relates to “scheduling a control channel” in wireless communications. Spec. 1:5–7, 10–12. For these communications, the application proposes using a technology in which an “unlicensed . . . spectrum is used as an extension to the licensed spectrum.” Id. at 2:14–19, 8:27–28. However, an “[u]nlicensed spectrum can, by definition, be simultaneously used by multiple different technologies.” Id. at 8:28–29, 2:23–24. Therefore, “[p]rior to occupying a channel in an unlicensed band, the network needs to check the availability of the channel by means of LBT [i.e., Listen-Before-Talk].” Id. at 9:4–5, 2:23–25. On the other hand, “[w]hen the network has already accessed a channel, it may, in the following and adjacent transmission time interval, start transmission immediately, e.g. from symbol 0, without performing LBT.” Id. at 9:5–7. The start time of the control channel therefore may depend on whether LBT is performed, but the “communication terminal” may not know in advance whether LBT is being performed because that is decided by the “radio access node,” not the communication terminal. Id. at 9:8–11. The claims here therefore propose a configuration for the communication terminal “to monitor at least two start positions for the control channel.” Id. at claim 1. ILLUSTRATIVE CLAIM Claim 1 is illustrative and reproduced below with certain limitations in dispute underlined: Appeal 2020-001806 Application 15/509,001 3 1. A method performed by a radio access node for scheduling a control channel to a communication terminal in a wireless communication network; wherein the radio access node serves the communication terminal in at least one of a first cell on a carrier of a licensed or unlicensed spectrum, and the communication terminal is further served in a second cell on a carrier of an unlicensed spectrum, comprising: - configuring the communication terminal with a configuration, which configuration defines that the communication terminal is to monitor at least two start positions for the control channel intended for the communication terminal, a first start position being used by the radio access node when the radio access node does not perform a Listen Before Talk, LBT, process and a second start position being used by the radio access node when the radio access node does perform a LBT process; - determining whether a LBT process is to be performed or not in the second cell; - scheduling, based on whether the LBT process is to be performed in a subframe on the second cell or not, the control channel with a start position in the subframe out of the at least two start positions; and - transmitting control information on the control channel as scheduled to the communication terminal. REFERENCES The Examiner relies on the following references as prior art: Name Reference Date Damnjanovic US 2015/0245327 A1 Aug. 27, 2015 Kaur US 2015/0131536 A1 May 14, 2015 Kim (“Kim2”) US 2014/0036889 A1 Feb. 6, 2014 Kim (“Kim1”) US 2014/0112289 A1 Apr. 24, 2014 Park US 2015/0223208 A1 Aug. 6, 2015 Appeal 2020-001806 Application 15/509,001 4 REJECTIONS The Examiner makes the following rejections under 35 U.S.C. § 103. The Examiner withdrew the rejection under 35 U.S.C. § 101. Ans. 3. Claims References Final Act. 1, 4, 6, 7, 9, 13–15 Kim1, Damnjanovic, Kim2 3 2, 3, 10–12 Kim1, Damnjanovic, Kim2, Park 9 5 Kim1, Damnjanovic, Kim2, Kaur 10 ISSUE Did the Examiner err in finding Kim1, alone or in combination with Kim2, teaches or suggests “the communication terminal is to monitor at least two start positions for the control channel intended for the communication terminal, a first start position being used by the radio access node when the radio access node does not perform a Listen Before Talk, LBT, process and a second start position being used by the radio access node when the radio access node does perform a LBT process,” as recited in claim 1? ANALYSIS Claim 1 recites a radio access node configuring a communication terminal with a configuration defining that “the communication terminal is to monitor at least two start positions for the control channel intended for the communication terminal, a first start position being used by the radio access node when the radio access node does not perform a Listen Before Talk, LBT, process and a second start position being used by the radio access node when the radio access node does perform a LBT process.” We are not persuaded by Appellant’s arguments that there is a “fundamental difference” between what Kim1 discloses and the claimed limitation. See Appeal Br. 21–24. Appeal 2020-001806 Application 15/509,001 5 The Specification discloses that “[t]he control information for a given communication terminal is transmitted using one or multiple Physical Downlink Control Channels (PDCCH)” and “[t]ypically the control region may comprise many PDCCH carrying control information to multiple communication terminals simultaneously.” Spec. 3:26–32; see also id. at 5:13–15. “The PDCCH . . . is used to carry Downlink Control Information (DCI) in a scheduling DCI message such as scheduling decisions and power- control commands.” Id. at 4:29–31. For Kim1, the Examiner relies on “PDCCH” as the claimed “control channel” and “carrier sensing” as the claimed “Listen Before Talk” (LBT). Final Act. 3–4. In particular, the Examiner finds that “Kim1 discloses a PDCCH can be transmitted at the start of a sub-frame, Para [0192]/Fig. 18 and can also be transmitted starting after carrier sensing is performed, Para [0206]/Fig. 20, which means there are at least two starting locations for transmitting the PDCCH.” Ans. 3–4. Appellant likewise concedes that “PDCCH in different locations depending on whether or not LBT is performed” is “disclosed in Kim1.” Appeal Br. 22. Thus, there is no dispute that Kim1 discloses multiple starting locations for PDCCH based on whether carrier sensing (i.e., LBT) is performed. The next question is whether Kim1 teaches or suggests the communication terminal (i.e., the “user equipment” or “UE” in Kim1) monitoring at least two start positions for the control channel (i.e., PDCCH). The Examiner sets forth two ways that Kim1 teaches or suggests this. The Examiner’s first approach involves deciding where within a control region a particular PDCCH will go. See Ans. 4–5. For background, Appellant explains that Appeal 2020-001806 Application 15/509,001 6 a PDCCH comprises multiple Control Channel Elements (CCEs). Each CCE comprises 9 Resource Element Groups (REGs). Each REG contains 4 contiguous (in frequency) Resource Elements (REs). CCEs have a logical index number, are distributed across the system bandwidth, and are located within the PDCCH region of the subframe. The PDCCH region of the subframe can contain multiple PDCCHs. Appeal Br. 23 (footnote omitted). Kim1 supports Appellant’s description. Kim1 ¶¶ 68, 71–72, Table 1. In particular, Kim1 discloses that “a plurality of PDCCHs can be transmitted within a control region” and a “UE can monitor a plurality of the PDCCHs.” Id. ¶ 68. However, “[t]he number of CCEs used for a transmission of a specific PDCCH varies” from one to eight depending on which of four “PDDCH formats” is used for that specific PDCCH. Id. ¶¶ 71–72, Table 1. According to Kim1, the UE is “not informed” which particular format is used, so the UE has to perform “blind decoding” to look for its PDCCH. Id. ¶ 74. Kim1 explains that “decoding all available CCEs used for a DL according to each PDCCH format may become a big burden to the UE,” so Kim1 proposes narrowing the number of decoding attempts by defining a “search space.” Id. ¶ 74. “In particular, the search space is a set of candidate PDCCHs consisted of CCEs where the UE should perform a decoding attempt on an aggregation level.” Id. ¶ 75, Table 2. “Each UE monitors (performing a decoding attempt on a set of PDCCH candidates according to an available DCI format) the UE-specific search space” and checks whether certain values there are valid. Id. ¶ 77. Appellant argues that Kim1 discloses “telling the UE which CCEs to decode within a PDCCH of a known location,” but argues that is different than “notifying the UE where the PDCCH may be located.” Appeal Br. 23. Appeal 2020-001806 Application 15/509,001 7 We are not persuaded by Appellant’s argument. Assuming a control region exists at a known location, Appellant has not sufficiently explained why checking specific CCEs within a control region for a valid PDCCH is any different than checking different “start positions” for PDCCH. As Appellant states, “CCEs are found at various, well-defined locations within the control channel of the subframe in the time domain.” Reply Br. 3 (emphasis omitted). Appellant does suggest that “looking for the start of a control channel in two different locations in time as claimed” is somehow different from Kim1’s search space for CCEs “distributed across the system bandwidth in the frequency domain.” See Reply Br. 3–7 (some emphasis omitted). We note, however, that the claims only recite a “start position” without specifying whether that position is in the time domain or frequency domain. Appellant further argues that the Examiner’s determination above “presumes that the beginning of the subframe is also known,” which may not be the case when doing LBT. See Reply Br. 6. The Examiner, however, also proposes a second approach that combines Kim1 with Kim2. According to the Examiner, “Kim2 discloses information regarding carrier sensing may be shared beforehand between the eNB and the UE, . . . and the carrier sensing position may be indicated in the form of an offset.” Ans. 6 (citing Kim2 ¶ 202). “This means the UE knows beforehand if a sub- frame is configured with a carrier sensing instance.” Id. “In view with Kim1, the first start position of the PDCCH is at the conventional location, at the start of the sub-frame, when no carrier sensing is performed and the second PDCCH start position, is after the carrier sensing when carrier sensing is performed in that sub frame.” Id. (citing Kim1 ¶ 206, Fig. 20). Appeal 2020-001806 Application 15/509,001 8 Although Kim2 discloses indicating the start location of PDSCH (Physical Downlink Shared Channel), “Fig. 20 [of Kim1] discloses the PDCCH can be in the PDSCH region, right after performing carrier sensing (i.e. second start location).” Id. at 6–7. Thus, the Examiner determines that it would have been obvious to one of ordinary skill in the art that the start location for PDSCH in Kim2 also would be the start location for PDCCH as in Kim1. Id. at 6. Appellant has not persuaded us of error in the Examiner’s combination. Although Kim2 alone does not teach or suggest the disputed limitation, see Reply Br. 9–10, Appellant has not explained why the Examiner’s combination of Kim1 and Kim2 would not teach or suggest monitoring two start positions for PDCCH, one at the beginning of the subframe if no LBT is performed and another after an offset if LBT is performed, where PDCCH is in the PDSCH region as in Kim1. Appellant argues claims 4, 7, 9, and 13–15 are patentable through their dependence on claim 1. Appeal Br. 26. For the reasons discussed above for claim 1, we are not persuaded of error. Appellant argues Park and Kaur do not cure the deficiencies of Kim1, Damnjanovic, and Kim2. Appeal Br. 27–28. For the reasons discussed above, we are not persuaded Kim1, Damnjanovic, and Kim2 are deficient. Accordingly, we sustain the Examiner’s rejections of claims 1–7 and 9–15. See 37 C.F.R. § 41.37(c)(1)(iv). Appeal 2020-001806 Application 15/509,001 9 OUTCOME The following table summarizes the outcome of each rejection: Claim(s) Rejected 35 U.S.C. § Reference(s)/Basis Affirmed Reversed 1, 4, 6, 7, 9, 13–15 103 Kim1, Damnjanovic, Kim2 1, 4, 6, 7, 9, 13–15 2, 3, 10–12 103 Kim1, Damnjanovic, Kim2, Park 2, 3, 10–12 5 103 Kim1, Damnjanovic, Kim2, Kaur 5 Overall Outcome 1–7, 9–15 TIME TO RESPOND No time period for taking any subsequent action in connection with this appeal may be extended under 37 C.F.R. § 1.136(a). See 37 C.F.R. § 1.36(a)(1)(iv). AFFIRMED