DCT

2:21-cv-00213

Godo Kaisha IP Bridge 1 v. Telefonaktiebolaget LM Ericsson

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 2:21-cv-00213, E.D. Tex., 06/11/2021
  • Venue Allegations: Plaintiff alleges venue is proper in the Eastern District of Texas based on Defendant Ericsson USA having its U.S. headquarters and a significant physical presence in Plano, Texas, operating a factory in Lewisville, Texas, and deploying products into the stream of commerce through contracts with major telecommunications carriers providing service within the district.
  • Core Dispute: Plaintiff alleges that Defendant’s 4G LTE and 5G telecommunications infrastructure products, such as base stations, infringe seven U.S. patents relating to fundamental aspects of mobile communication standards.
  • Technical Context: The technologies at issue involve methods for managing control channels, data channels, reference signals, and feedback reporting in modern wireless networks, which are central to the operation of the 4G LTE and 5G standards.
  • Key Procedural History: The complaint notes that the original assignee of the patents-in-suit, Panasonic Corporation, and later Plaintiff IP Bridge, submitted licensing declarations to the European Telecommunications Standards Institute (ETSI), identifying certain patents as potentially essential to the LTE and/or 5G standards and stating a preparedness to grant irrevocable licenses on fair, reasonable, and non-discriminatory (FRAND) terms.

Case Timeline

Date Event
2002-04-17 Earliest Priority Date for ’909 and ’000 Patents
2007-03-19 Earliest Priority Date for ’724 Patent
2007-08-08 Earliest Priority Date for ’275 and ’594 Patents
2007-08-13 Earliest Priority Date for ’546 Patent
2008-05-06 Earliest Priority Date for ’239 Patent
2008-05-13 ’909 Patent Issued
2009-07-16 Panasonic ETSI Declaration for ’909 and ’000 Patents
2010-10-25 Panasonic ETSI Declaration for ’724, ’594, and ’239 Patents
2011-12-13 ’594 Patent Issued
2011-12-27 ’724 Patent Issued
2013-02-26 ’239 Patent Issued
2013-06-06 Panasonic ETSI Declaration for ’546 Patent
2013-08-06 Panasonic ETSI Declaration for ’275 Patent
2013-09-03 ’546 Patent Issued
2014-07-22 ’275 Patent Issued
2015-09-15 ’000 Patent Issued
2020-10-15 IP Bridge ETSI Declaration for ’275, ’724, and ’000 Patents
2021-06-11 Complaint Filed

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 7,372,909 - “Radio Transmitting Apparatus, Radio Receiving Apparatus and Method Therefor,” Issued May 13, 2008

The Invention Explained

  • Problem Addressed: The patent describes a problem in prior art multicarrier communication systems where a data channel and a control channel have different center frequencies (Compl. ¶31; ’909 Patent, col. 1:32-35). This required a receiving apparatus to change the frequency of its local signal when switching between receiving the control channel and the data channel, a process that was slow and could prevent high-speed switching (’909 Patent, col. 1:47-57).
  • The Patented Solution: The invention proposes assigning the control channel and data channel subcarriers such that they share a common center frequency (Compl. ¶34). By locating the control channel at the center of the frequency band used for the data channel, a receiving apparatus can use a single, common local frequency for down-conversion, eliminating the need to switch frequencies and thereby speeding up the process of switching between the channels (’909 Patent, Abstract; col. 4:23-31). This concept is illustrated in the patent’s Figure 4.
  • Technical Importance: This approach aimed to simplify receiver design and increase the speed and efficiency of channel switching in OFDM-based systems, a key consideration for improving performance in mobile communications (Compl. ¶32).

Key Claims at a Glance

  • The complaint asserts independent method claim 5 (Compl. ¶84).
  • Claim 5 recites the essential elements of a method for transmitting an OFDM multicarrier signal:
    • assigning a data channel to a first plurality of subcarriers and a control channel to a second plurality of subcarriers;
    • assigning the second plurality of subcarriers such that they are located between the first plurality of subcarriers on a frequency axis;
    • the center frequency of the data channel and the center frequency of the control channel are common;
    • up-converting the multicarrier signal to a carrier frequency; and
    • transmitting the up-converted multicarrier signal.

U.S. Patent No. 8,787,275 - “Wireless Communication Base Station Equipment, Wireless Communications Terminal Device and Search Space Setting Method,” Issued July 22, 2014

The Invention Explained

  • Problem Addressed: The patent addresses limitations in systems using multiple component bands (i.e., carrier aggregation). When a terminal is allocated multiple bands, using a single "search space" to find control channel information for all bands limits the amount of control information that can be transmitted, which in turn can limit data throughput (’275 Patent, col. 4:21-39; Compl. ¶40).
  • The Patented Solution: The invention proposes a method for a base station to set a plurality of distinct search spaces for a plurality of component bands (Compl. ¶39). The patent describes setting these search spaces so that they "neighbor each other," which is intended to minimize the amount of searching a terminal must perform, thereby reducing power consumption (’275 Patent, col. 10:56-59). By defining separate search spaces, the system avoids limitations on control channel element allocation that arise from using a single shared space, reducing the possibility that data transmission is limited by a lack of available control resources (’275 Patent, col. 12:31-38).
  • Technical Importance: This method provided a more scalable and efficient way to manage control signaling in LTE-Advanced and subsequent systems that rely on aggregating multiple frequency bands to achieve higher data rates (Compl. ¶39).

Key Claims at a Glance

  • The complaint asserts independent apparatus claim 13 (Compl. ¶97).
  • Claim 13 recites the essential elements of a base station apparatus:
    • an assigning section for assigning a downlink control channel for a terminal to a control channel element (CCE) in a first search space;
    • the downlink control channel includes resource assignment information for a component carrier n (CCn);
    • a transmitting section for transmitting the downlink control channel;
    • wherein a CCE number defining an end position of the first search space for CCn and a CCE number defining a start position of a second search space for a component carrier n+1 (CCn+1) are consecutive, with the second search space being different from the first.

Multi-Patent Capsules

  • U.S. Patent No. 8,085,724, “Sequence Report Method and Sequence Report Device,” Issued Dec. 27, 2011

    • Technology Synopsis: This patent addresses the signaling of sequences used for generating random access preambles in cellular systems (Compl. ¶46). To reduce the signaling overhead required to inform a terminal of available preambles, the invention correlates sequences to consecutive indices and groups them based on properties like maximum applicable cyclic shift, allowing a base station to report a group of sequences using a single index (Compl. ¶¶47, 49).
    • Asserted Claims: Claim 18 (Compl. ¶111).
    • Accused Features: The accused feature is the allocation and reporting of preamble sequences in Ericsson's LTE and 5G products, which allegedly implement a mapping of consecutive logical indexes to root sequences as defined by the 3GPP standards (Compl. ¶112).

  • U.S. Patent No. 8,077,594, “Radio Communication Base Station Device and Correlation Setting Method,” Issued Dec. 13, 2011

    • Technology Synopsis: The patent addresses the problem of decreasing data transmission efficiency when resources are used for sounding reference signals (SRS) (Compl. ¶54). The invention proposes a method to transmit an SRS from one device during the "guard time" of a random access preamble being transmitted by another device, a period during which nothing would otherwise be transmitted, thereby creating additional resources for reference signals without causing interference (Compl. ¶55).
    • Asserted Claims: Claim 13 (Compl. ¶122).
    • Accused Features: The accused feature is the reception of an SRS that is mapped to the position of a guard time in a subframe where a random access preamble is transmitted, as allegedly practiced by Ericsson's LTE products (Compl. ¶123). The complaint includes a diagram from a 3GPP standard illustrating the preamble format that includes a cyclic prefix, sequence, and guard time (Compl. ¶124).

  • U.S. Patent No. 8,385,239, “Control Channel Signalling for Triggering the Independent Transmission of a Channel Quality Indicator,” Issued Feb. 26, 2013

    • Technology Synopsis: The patent addresses inefficiencies in reporting channel quality information (CQI). Prior art methods required aperiodic CQI reports to be sent concurrently with user data (Compl. ¶61). The invention provides a specific control signaling scheme that allows a base station to request a terminal to send a CQI report without data, which is particularly useful in poor channel conditions to improve the reliability of the CQI report (Compl. ¶62).
    • Asserted Claims: Claim 14 (Compl. ¶136).
    • Accused Features: The accused feature in Ericsson's LTE base stations is a transmitter that sends a control signal triggering an aperiodic CQI report, where the report is not multiplexed with user data under certain conditions defined by the MCS Index and number of resource blocks (Compl. ¶¶138-142).

  • U.S. Patent No. 8,526,546, “Radio Transmission Device and Radio Transmission Method,” Issued Sep. 3, 2013

    • Technology Synopsis: This patent addresses interference between different types of signals, such as ACK/NACK and CQI, that are transmitted concurrently using cyclically shifted ZC sequences (Compl. ¶68). The invention provides a method to reduce this interference by applying orthogonal Walsh codes to the ACK/NACK signals while setting reference signal symbols in the CQI signals to be in an opposite phase (Compl. ¶69).
    • Asserted Claims: Claim 6 (Compl. ¶153).
    • Accused Features: The accused features are the reception and processing of ACK/NACK and CQI signals in Ericsson's LTE products, which allegedly use orthogonal sequences and specific symbol arrangements for data and reference signals as defined in 3GPP standards (Compl. ¶¶154-157). The complaint includes a table from the 3GPP TS 36.211 standard showing orthogonal sequences used for ACK/NACK signal transmission (Compl. ¶155).

  • U.S. Patent No. 9,137,000, “Base Station Apparatus and Method for Controlling Channel Quality Indicator Transmission,” Issued Sep. 15, 2015

    • Technology Synopsis: The patent addresses the problem of excessive control information and power consumption when a terminal must report the CQI for every subcarrier block (Compl. ¶75). The invention provides a method for a base station to reduce this overhead by determining whether to request one CQI for each subcarrier block or a single CQI for all subcarrier blocks within the communication frequency band (Compl. ¶¶76, 78).
    • Asserted Claims: Claim 1 (Compl. ¶171).
    • Accused Features: The accused feature is the transmission of control information in Ericsson's LTE and 5G products that indicates whether a mobile station should transmit a wideband CQI (for all subcarrier blocks) or a subband/multi-band CQI (for a subset of blocks) (Compl. ¶172).

III. The Accused Instrumentality

Product Identification

The accused instrumentalities are Ericsson’s products compliant with the 4G LTE and 5G standards, specifically identified as LTE and 5G base stations (eNodeBs and gNBs), including the Radio Base Station (RBS) 6000 Series (Compl. ¶¶ 81-82, 97).

Functionality and Market Context

The accused products are infrastructure equipment that form the core of modern cellular networks (Compl. ¶¶ 81, 97). Their function is to manage radio communications with mobile devices according to the 3GPP technical standards for 4G LTE and 5G (Compl. ¶¶ 81-82). The complaint alleges these products are used by major U.S. carriers, including Verizon, AT&T, and T-Mobile, to provide nationwide 4G and 5G services, underscoring their central role in the U.S. telecommunications market (Compl. ¶¶ 9-21). The complaint includes several coverage maps from these carriers to illustrate the widespread deployment of networks that allegedly use the accused Ericsson products (Compl. pp. 4, 6, 8).

IV. Analysis of Infringement Allegations

’909 Patent Infringement Allegations

Claim Element (from Independent Claim 5) Alleged Infringing Functionality Complaint Citation Patent Citation
a method for transmitting an OFDM multicarrier signal comprising a first plurality of subcarriers and a second plurality of subcarriers The accused products transmit an OFDM signal comprising PDSCH subcarrier signals (data) and PBCH subcarrier signals (control). ¶85 col. 4:3-7
said method comprising: assigning a data channel to the first plurality of subcarriers and a control channel to the second plurality of subcarriers The accused products map the PDSCH (Physical Downlink Shared Channel) to a first set of subcarriers and the PBCH (Physical Broadcast Channel) to a second set of subcarriers. ¶85 col. 3:1-10
assigning the second plurality of subcarriers are located between the first plurality of subcarriers on a frequency axis The resource element indices for the PBCH are defined by the 3GPP standard to place the PBCH immediately around the center frequency, with the PDSCH mapped to resource elements such that the PBCH is located between PDSCH subcarriers. ¶86 col. 4:32-34
and the center frequency of the data channel and the center frequency of the control channel are common The placement of the PBCH at the center of the channel ensures that its center frequency is common with that of the overall data channel. ¶86 col. 4:32-34
up-converting the multicarrier signal to a carrier frequency; and transmitting the up-converted multicarrier signal The 3GPP standard specifies modulation and upconversion to the carrier frequency for the complex-valued OFDM baseband signal, which is then transmitted over antennae. ¶87 col. 3:20-25
  • Identified Points of Contention:
    • Scope Questions: A central question may be whether the mapping of the PBCH "immediately around the center frequency" as specified in the 3GPP standard meets the claim limitation that the control channel is "located between the first plurality of subcarriers." The analysis could depend on whether "between" requires the data subcarriers to fully enclose the control subcarriers.
    • Technical Questions: The complaint alleges the center frequencies are "common" based on the PBCH's central location. A potential point of dispute is how "center frequency of the data channel" is defined, especially since the PDSCH (data channel) subcarriers are not necessarily contiguous and are mapped around the centrally located PBCH.

’275 Patent Infringement Allegations

Claim Element (from Independent Claim 13) Alleged Infringing Functionality Complaint Citation Patent Citation
an assigning section configured to assign a downlink control channel for a terminal, for which one or multiple component carriers (CC(s)) are configured, to a control channel element (CCE) in a first search space comprised of a plurality of CCEs The accused products assign the Physical Downlink Control Channel (PDCCH) for a user equipment (UE) to one or more CCEs within a first search space assigned to that UE. ¶98 col. 6:30-36
wherein the downlink control channel includes resource assignment information indicating a resource allocated to the terminal in a component carrier n (CCn) out of the configured CC(s) The PDCCH contains a carrier indicator and a resource block assignment for the UE, which indicates the allocated resource in a specific component carrier. ¶99 col. 7:14-23
a transmitting section configured to transmit the downlink control channel to the terminal in the CCE... The accused products transmit the PDCCH to the UE on one or more CCEs within the monitored search space. ¶100 col. 12:35-38
wherein a CCE number that defines an end position of the first search space for the CCn and a CCE number that defines a start position of a second search space for a component carrier n+1 (CCn+1) are consecutive, the second search space being different from the first search space The 3GPP standard defines a UE's search space for a component carrier as a continuous set of CCEs. The search space for the next component carrier (n+1) starts at the CCE immediately following the last CCE of the search space for the previous component carrier (n), making the end and start CCE numbers sequential. ¶101 col. 10:56-59
  • Identified Points of Contention:
    • Scope Questions: The interpretation of the term "consecutive" will be critical. The complaint alleges that the CCE number for the start of the second search space is "sequential to the last CCE number for the search space for the nth component carrier." A court will need to determine if this implementation, as defined by the 3GPP standard, meets the legal definition of "consecutive" as used in the claim.
    • Technical Questions: What evidence does the complaint provide that the CCE numbering scheme in practice is strictly sequential across component carrier boundaries as required? The defense could explore whether any protocol-level functions, such as CCE aggregation levels or other logical mappings, disrupt a strictly consecutive numerical relationship between the end of one search space and the start of the next.

V. Key Claim Terms for Construction

’909 Patent

  • The Term: "common center frequency"
  • Context and Importance: This term is central to the invention's alleged departure from the prior art. The infringement theory depends on the accused LTE products' PBCH and PDSCH having a "common center frequency." Practitioners may focus on this term because its definition will determine whether the standardized arrangement of control and data channels falls within the claim's scope.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The specification explains that the benefit of the common frequency is that "the local frequency does not need to be changed" when switching channels, which "can be speeded up" (col. 4:23-26). This functional goal, rather than a requirement for perfect mathematical identity of the center points of two distinct channel definitions, could support a broader reading that covers any arrangement achieving this single-local-oscillator benefit.
    • Evidence for a Narrower Interpretation: The claim language recites that "the center frequency of the data channel and the center frequency of the control channel are common." This could be interpreted narrowly to require that two separately identifiable center frequencies are identical. An opponent might argue that in the accused products, the PDSCH does not have a distinct "center frequency" separate from the overall channel, raising a question of antecedent basis and definitional mismatch.

’275 Patent

  • The Term: "consecutive"
  • Context and Importance: The infringement allegation hinges on the claim that the CCE number ending one search space and the CCE number starting the next are "consecutive." The viability of the infringement case against the 3GPP standard will depend entirely on how this term is construed.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The patent describes the goal as setting search spaces that "neighbor each other" to minimize searching and power consumption (col. 10:56-59). This suggests the core inventive concept is adjacency, not necessarily strict numerical sequence. A party could argue that "consecutive" should be interpreted in light of this functional goal, covering any arrangement where one search space immediately follows another without a gap, as alleged in the complaint (Compl. ¶101).
    • Evidence for a Narrower Interpretation: The plain meaning of "consecutive" implies an unbroken numerical sequence (e.g., 8, 9, 10). A defendant could argue that the claim requires the CCE index itself to be sequential (e.g., CCE #N is immediately followed by CCE #N+1). They might then argue that the logical-to-physical mapping of CCEs or other standard-defined processes break this strict numerical sequence, defeating infringement.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges inducement by asserting that Ericsson knowingly encourages infringement by marketing and selling its LTE and 5G products with the knowledge and intent that its customers will operate them in an infringing manner to build out their networks (Compl. ¶¶ 91, 105, 116, 130, 147, 165, 177). Contributory infringement is alleged on the basis that the accused products are especially made to practice the LTE/5G standards, constitute a material part of the claimed inventions, and are not staple articles of commerce with substantial non-infringing uses (Compl. ¶¶ 92, 106, 117, 131, 148, 166, 178).
  • Willful Infringement: The complaint alleges willful infringement based on pre-suit knowledge. It claims that on March 4, 2015, IP Bridge alerted Ericsson that a portfolio of patents essential to the LTE standard, which included the ’909, ’724, ’594, ’239, ’546, and the parent of the ’000 patents, was owned by IP Bridge (Compl. ¶¶ 90, 115, 129, 146, 164, 176). Post-suit knowledge is also alleged based on the filing of the complaint itself (Compl. ¶¶ 90, 104).

VII. Analyst’s Conclusion: Key Questions for the Case

  • A core issue will be one of definitional scope: can claim terms rooted in general radio engineering concepts, such as "common center frequency" (’909 Patent) and "consecutive" (’275 Patent), be construed to read on the specific, complex, and highly detailed implementations found in the 3GPP standards for LTE and 5G? The outcome will likely depend on whether the court adopts a functional interpretation based on the problems the patents claim to solve or a stricter, literal interpretation of the claim language.
  • A second central question will be one of standards-essentiality and damages: given the Plaintiff's and its predecessor's declarations to ETSI regarding a willingness to license on FRAND terms, the case may focus heavily on whether the patents are indeed essential to the LTE and/or 5G standards and, if so, what constitutes a reasonable royalty under FRAND obligations, potentially overshadowing a technical finding of infringement.