HTC Corp. v. Cellular Commc'ns Equip., LLC

• Decision Date: 18 December 2017
• Docket Number: 2016-1880
• Citation: 877 F.3d 1361
• Parties: HTC CORPORATION, ZTE (USA), Inc., Appellants v. CELLULAR COMMUNICATIONS EQUIPMENT, LLC, Appellee
• Court: U.S. Court of Appeals — Federal Circuit

877 F.3d 1361

HTC CORPORATION, ZTE (USA), Inc., Appellants

v.CELLULAR COMMUNICATIONS EQUIPMENT, LLC, Appellee

2016-1880

United States Court of Appeals, Federal Circuit.

Decided: December 18, 2017

Steven Arthur Moore, Pillsbury Winthrop Shaw Pittman LLP, San Diego, CA, argued for appellants. Also represented by Matthew Robert Stephens, Brian Christopher Nash, Austin, TX.

Barry James Bumgardner, Nelson Bumgardner PC, Fort Worth, TX, argued for appellee. Also represented by John P. Murphy.

Before Dyk, Reyna, and Taranto, Circuit Judges.

Reyna, Circuit Judge.

HTC Corporation and ZTE (USA), Inc. appeal a final written decision of the Patent Trial and Appeal Board in an inter partes review. Appellants argue that the Board improperly construed the claim term "message" and erred in finding that HTC failed to show that the prior art anticipated or rendered obvious the challenged claims. We find no error in the Board's claim construction, and substantial evidence supports the Board's patentability determination. We affirm.

BACKGROUND

A. The '174 Patent

U.S. Patent No. 7,941,174 (" '174 patent") is directed to methods and apparatuses for a radio communications system where a subscriber station, i.e., a mobile device, is assigned a plurality of codes for transmitting messages. '174 Patent Abstract, col. 2 ll. 1–6. The assigned codes correspond to data transmission channels in a Universal Mobile Telecommunications System ("UMTS"), in particular here, a Dedicated Uplink Channel ("DCH") for transmitting messages and an Enhanced Dedicated Uplink Channel ("EDCH") for transmitting high bit rate messages. Id. col. 4 ll. 26–40. To send messages to a UMTS base station, the subscriber station requires "transmit" or "transmission" power. When radio transmission conditions deteriorate, such as when there is a high amount of interference in the communications cell, the base station may command the subscriber station to increase transmit power in order to send the message. Id. col. 7 ll. 20–26, 31–33; J.A. 2125. But the subscriber station is limited in the amount of transmission power it can use, called the "maximum transmission power," which is "preferably predetermined by the hardware of the subscriber station" or "predefined on the network side." Id. col. 2 ll. 50–51, 57–58. According to the '174 patent, operating at maximum transmission power is undesirable because the subscriber station cannot increase transmission power to overcome poor transmission conditions, which in turn results in incomplete and aborted message transmissions. See id. col. 6 ll. 20–27.

To avoid operating at maximum transmission power, the '174 patent's claimed solution sets a "transmit power difference" or "power headroom" for the plurality of codes in the subscriber station at the beginning of a message transmission. Id. col. 6 ll. 40–47. Setting this power headroom permits the subscriber station when sending messages to increase transmit power to overcome interference and thus avoid aborted message transmission. The transmit power difference "corresponds to an unused transmit power at the start of the transmission" of a message, such as a message transmitted over EDCH. Id. col. 6 ll. 47–49.

Illustrative of the method claims, independent claim 1 teaches:

1. A method for operating a radio communication system in which a subscriber station is assigned a plurality of codes for transmitting messages, comprising:

determining a transmit power difference which is to be maintained by the subscriber station between on one hand a total maximum transmit power of the subscriber station for the codes and on another hand a total transmit power of the subscriber station for the codes at a start of a message transmission using a first one of the codes.

Id. col. 9 ll. 56–64.

Illustrative of the apparatus claims, independent claim 18 teaches:

18. A subscriber station for a radio communication system, the subscriber station assigned a plurality of codes for transmitting messages, comprising:

at least one processor programmed to determine a transmit power difference which is to be maintained by the subscriber station between on one hand a total maximum transmit power of the subscriber station for the codes and on another hand a total transmit power of the subscriber station for the codes at a start of a message transmission using a first one of the codes.

Id. col. 12 ll. 1–10.

The sole figure in the specification depicts the relationship between the mobile station, UE, which transmits messages over the DCH and EDCH channels, and base station, NODE B, in a UMTS system:

Id. Fig. 1.

Relevant to this appeal, the '174 patent recognizes that an EDCH message is measured in intervals of 10 milliseconds, which is comprised of 15 timeslots. Id. col. 5 ll. 29–31. The 10 ms transmission time interval is referred to as a "frame." See J.A. 1181–82, 2130. In UMTS systems available around 1999, transmission time intervals could either be 10 ms, 20 ms, 40 ms, or 80 ms. J.A. 2128.

B. Prior Art

1. Baker

U.S. Patent Application Pub. No. 2008/0151840 ("Baker") is directed to a UMTS communication system in which a mobile station transmits acknowledgement ("ACK") or non-acknowledgement ("NACK") signals to a base station upon receiving data from the base station. J.A. 909. To allow for the transmission of ACK/NACK signals, the mobile station must scale down the maximum transmit power allocated to its transmission codes: a dedicated physical data channel ("DPDCH") and a dedicated physical control channel ("DPCCH"). Id. Figure 4 depicts this process in a timing diagram, with P_C1and P_D1representing the transmit power associated with each of the two transmission channels, DPDCH and DPCCH, operating at maximum transmission power for the mobile station, P_max. When the ACK/NACK signal is to be transmitted, P_C1and P_D1are scaled down to P_C2and P_D2, respectively, for the duration of the ACK/NACK transmission.

See J.A. 911, 914.

As Baker explains, "at the boundary of the frame or time slot immediately preceding the sending of an ACK or NACK, these amplitudes [P_C1and P_D1] are adjusted by for example reducing DPCCH whilst maintaining the power ratio P_D/P_Cconstant." Id. Baker thus leaves capacity for the transmission of the ACK/NACK signal, or other types of signaling information. J.A. 914–15.

2. Reed

U.S. Patent No. 7,689,239 ("Reed") is directed to a system, method, and apparatus for "establishing headroom for a mobile station" based on "specific channel variance conditions and battery conditions." J.A. 901 Abstract. Reed defines "headroom" as "the difference between the maximum power of the transmitter and the transmission power level required for a particular data rate." J.A. 905 col. 1 ll. 29–31. Headroom is therefore a "margin built in" to the maximum data rate "to provide some protection against varying channel conditions." Id. col. 1 ll. 36–38. In the sole portion of the written description discussing a mobile station with multiple data streams, Reed states:

If the mobile station desires to send two or more data streams (or hold voice and data connections at the same time), an addition [sic] degree of freedom allows the mobile station to deliberately increase the headroom on one of the data streams to de-prioritize that data stream. This would result in, for example, a longer time to transmit a text message from the mobile station but allow a digital picture to be transmitted at an optimum data rate.

J.A. 906 col. 4 ll. 14–21.

3. Love

U.S Patent No. 7,321,780 ("Love") is directed to "a method for rate selection by a communication device for enhanced uplink during soft handoff in a wireless communication system." J.A. 917. Relevant here, Love discloses assigning codes to communication channels to transmit data and setting a "power margin" to limit the rate of data transmitted over the codes. Id. col. 6 ll. 11–19, col. 8 ll. 42–55. With respect to obviousness, HTC only challenges the Board's review of the scope and content of Reed.

C. Proceedings Before the Board

The Board instituted inter partes review of claims 1, 6, 9, 14, 18, and 19 of the '174 patent on three grounds: (1) anticipation by Baker; (2) obviousness over Reed in view of Baker; and (3) obviousness over Reed in view of Love. Amazon.com, Inc. v. Cellular Commc'ns Equip., LLC , No. IPR2014-01134, 2016 WL 98583, at *1 (P.T.A.B. Jan. 6, 2016) (" Final Written Decision ").¹ On January 6, 2016, the Board issued a final written decision concluding that petitioners, including appellants HTC Corporation and ZTE (USA), Inc. (together, "HTC"), failed to show that any of the challenged claims were unpatentable. Id. at *11.

First, the Board adopted patent owner's, Cellular Communications Equipment, LLC ("CCE"), construction of the phrase "at a start of a message transmission using a first one of the codes," as it appears in claims 1, 9, and 18, to modify the phrase "a total transmit power of the subscriber station for the codes." Id. at *5.² The Board thus interpreted the "start of a message transmission using a first one of the codes" limitation to require that a total transmit power difference exist at the start of a message transmission. Id.

Second, the Board found that HTC failed to show that Baker either explicitly or inherently disclosed the "start of a message transmission" limitation of the '174 patent. The Board reasoned that Baker did not disclose any indication that the frame or timeslot boundary immediately preceding an ACK/NACK signal is the start of a message transmission. Id. at *6. The Board then considered whether Baker inherently discloses the "start of a message transmission" limitation. It found that HTC provided no evidence that Baker discloses a mobile station that transmits EDCH messages, and thus HTC failed to show that the start of a frame preceding an ACK/NACK signal is necessarily the start of a message transmission. Id. at *6. The Board reasoned that the "mere possibility that the start of a frame may correspond to the start of a message transmission is...