DCT
2:15-cv-00580
Cellular Communications Equipment LLC v. T-Mobile USA Inc
Key Events
Complaint
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Cellular Communications Equipment LLC (Texas)
- Defendant: T-Mobile USA, Inc. (Delaware), et al.
- Plaintiff’s Counsel: Bragalone Conroy PC
- Case Identification: 2:15-cv-00580, E.D. Tex., 04/30/2015
- Venue Allegations: Venue is based on allegations that Defendants reside in the district, have committed acts of infringement in the district, and maintain regular and established places of business within the district.
- Core Dispute: Plaintiff alleges that Defendants’ LTE-compliant mobile devices and network infrastructure infringe three patents related to methods for efficient signaling of network control information.
- Technical Context: The technology addresses the management of wireless spectrum in 4G LTE networks by defining more efficient methods for communicating redundancy versions, power headroom, and channel state information.
- Key Procedural History: The complaint alleges that U.S. Patent No. 8,457,022 is essential to the 3GPP LTE standard and that Defendants had notice of it as early as December 2012 through standards body disclosures. For the other two patents, notice is alleged as of the filing of the complaint. Subsequent to the complaint's filing, an Inter Partes Review (IPR) proceeding on U.S. Patent No. 8,867,472 (IPR2016-01480) resulted in the cancellation of several claims, including some asserted in this litigation.
Case Timeline
| Date | Event |
|---|---|
| 2008-03-26 | Priority Date for U.S. Patent No. 8,570,957 |
| 2008-09-22 | Priority Date for U.S. Patent No. 8,457,022 |
| 2010-03-25 | Priority Date for U.S. Patent No. 8,867,472 |
| 2012-12-31 | Alleged Notice of '022 Patent to Defendants |
| 2013-06-04 | Issue Date for U.S. Patent No. 8,457,022 |
| 2013-10-29 | Issue Date for U.S. Patent No. 8,570,957 |
| 2014-10-21 | Issue Date for U.S. Patent No. 8,867,472 |
| 2015-04-30 | Complaint Filing Date |
| 2019-07-26 | IPR Certificate Issued for '472 Patent (cancelling claims) |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 8,457,022 - Method and Apparatus for Providing Signaling of Redundancy Versions (Issued Jun. 4, 2013)
The Invention Explained
- Problem Addressed: The patent describes the challenge of efficiently signaling redundancy version (RV) information for broadcast transmissions in LTE networks. In such scenarios, the user equipment (UE) does not use an uplink channel to acknowledge receipt, so the base station (eNB) has flexibility in scheduling retransmissions. This creates ambiguity for the UE, which needs to know the correct RV to properly combine the original data with retransmitted data for error correction. (’022 Patent, col. 5:10-21, col. 6:10-21).
- The Patented Solution: The patent proposes a method for implicitly determining the RV sequence without explicit signaling. The solution involves detecting the start of a system information (SI) transmission window and assigning a predefined RV sequence (e.g., 0, 2, 3, 1). The assignment logic systematically excludes certain subframes that are unavailable for SI transmission (such as uplink or multicast subframes), ensuring the UE and eNB remain synchronized on the RV value for any given transmission opportunity. (’022 Patent, Abstract; col. 7:9-30; Fig. 2).
- Technical Importance: This method aims to improve spectral efficiency by eliminating the need for explicit RV signaling overhead, which is particularly valuable for broadcast channels where no uplink feedback is present. (’022 Patent, col. 2:32-35).
Key Claims at a Glance
- The complaint asserts infringement of apparatus and method claims without specifying numbers (Compl. ¶27). The first independent apparatus claim is Claim 6.
- Essential elements of Independent Claim 6 include:
- A redundancy version signaling module configured to detect a start of a system information message transmission window and assign a redundancy version sequence at the start.
- The assignment must exclude one or more predetermined subframes in even-numbered radio frames.
- The assignment must also exclude uplink subframes and multi-cast subframes.
- The assignment must ensure the RV sequence is continuous over adjacent radio frames.
- The RV sequence is calculated according to a specific formula provided in the claim.
- The complaint implicitly reserves the right to assert other claims, including method claims.
U.S. Patent No. 8,570,957 - Extension of Power Headroom Reporting and Trigger Conditions (Issued Oct. 29, 2013)
The Invention Explained
- Problem Addressed: Conventional power headroom reporting in LTE is limited to positive values, indicating how much extra transmission power a UE has available. If a UE lacks sufficient power for a scheduled transmission (a common issue at the cell edge), the report simply indicates 0 dB of headroom, failing to quantify the power deficit for the network. (’957 Patent, col. 5:1-12).
- The Patented Solution: The invention extends power headroom reporting to include negative values. A negative report explicitly quantifies the "missing power in dB," informing the base station exactly how much the UE is power-limited. This allows the base station to make more precise adjustments, such as reducing the allocated bandwidth or assigning a more robust, lower-rate modulation scheme. (’957 Patent, Abstract; col. 5:13-24).
- Technical Importance: By providing the network with granular data on power deficits, the invention enables more efficient radio resource management, which can improve overall system capacity and maintain service quality for power-limited users. (’957 Patent, col. 6:5-11).
Key Claims at a Glance
- The complaint asserts infringement of apparatus and method claims without specifying numbers (Compl. ¶39). The first independent apparatus claim is Claim 1.
- Essential elements of Independent Claim 1 include:
- A processor configured to determine a power headroom report.
- A transmitter configured to transmit the report.
- The processor determines the report with both positive and negative values, where negative values indicate the missing power in dB.
- The determination is made by subtracting the nominal maximum transmission power from the power the device would use without power limits, with the result not being limited to zero or positive values.
- The complaint implicitly reserves the right to assert other claims.
U.S. Patent No. 8,867,472 - Signalling of Channel Information (Issued Oct. 21, 2014)
Technology Synopsis
The patent addresses the challenge of signaling Channel State Information (CSI) in LTE systems that use carrier aggregation (i.e., multiple frequency bands). Requesting full, detailed CSI for every component carrier creates significant uplink signaling overhead. The invention provides a mechanism for a base station to trigger an aperiodic CSI report for a single, selected downlink component carrier, allowing the network to gather high-resolution channel data for a specific band of interest without requiring a full report for all bands. (’472 Patent, Abstract; col. 3:34-45; Compl. ¶48).
Asserted Claims
The complaint does not specify claims (Compl. ¶50). Independent claims include Claim 15 (apparatus) and Claim 44 (method). Notably, post-filing IPR proceedings canceled several claims, including independent claims 1 and 28.
Accused Features
The complaint alleges that Defendants' LTE User Equipment and Network Equipment, by implementing LTE standards for carrier aggregation, perform the claimed methods of selectively requesting and providing aperiodic CSI reports for specific component carriers. (Compl. ¶50-51).
III. The Accused Instrumentality
Product Identification
The complaint targets a broad class of products referred to as "T-Mobile LTE User Equipment and Network Equipment." (Compl. ¶9). This includes a wide array of smartphones and tablets (e.g., Apple iPhone 5/6, Samsung Galaxy S3/S4/S5/S6, LG G series) supplied by the device-maker Defendants, as well as LTE base station equipment (e.g., Alcatel-Lucent eNodeB, Ericsson RBS 6000 series) supplied by the infrastructure Defendants. (Compl. ¶26, ¶38, ¶50).
Functionality and Market Context
The complaint alleges that the accused products are designed to operate on T-Mobile’s 4G LTE network and necessarily implement the LTE wireless standards. (Compl. ¶2). The relevant functionality is the underlying control signaling used to manage network resources. Plaintiff asserts that this functionality is critical to T-Mobile’s ability to efficiently use its wireless spectrum and offer competitive LTE service. (Compl., Introduction).
No probative visual evidence provided in complaint.
IV. Analysis of Infringement Allegations
U.S. Patent No. 8,457,022 Infringement Allegations
| Claim Element (from Independent Claim 6) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a redundancy version signaling module configured to detect start of a system information message transmission window and to assign a redundancy version sequence at the start of the transmission window... | The accused LTE equipment allegedly implements a redundancy version signaling function that operates within system information windows as required by the LTE standard. | ¶26, ¶27 | col. 7:9-15 |
| wherein the assignment includes excluding one or more of the predetermined subframes in even-numbered radio frames... | The accused LTE equipment, in complying with LTE standards, allegedly excludes specific subframes (e.g., those reserved for SIB1 transmission) from the RV sequence calculation. | ¶26, ¶27 | col. 7:16-24 |
| and wherein the assignment includes excluding uplink subframes and multi-cast subframes... | The accused LTE equipment allegedly follows LTE protocols that exclude uplink and MBSFN (multicast) subframes from being used for certain downlink SI transmissions, thereby excluding them from the RV sequence. | ¶26, ¶27 | col. 7:25-30 |
- Identified Points of Contention: The analysis will likely focus on whether the specific rules for subframe exclusion and RV sequence calculation in the 3GPP LTE standard align with the precise language of Claim 6. A potential dispute is whether the standard's method for handling unavailable subframes constitutes "excluding" them in the manner claimed, or if it is a technically distinct process.
U.S. Patent No. 8,570,957 Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a processor configured to determine a power headroom report... with both positive and negative values of power headroom... | The accused LTE User Equipment allegedly determines and reports power headroom in a manner that conveys both surplus power and power deficits, as required by LTE standards. | ¶38, ¶39 | col. 9:11-19 |
| in which negative values indicate the missing power in dB to fulfill transmission requirements... | The complaint alleges the accused devices report power headroom in a way that quantifies the power deficit, which corresponds to the claimed "negative values." | ¶38, ¶39 | col. 5:18-24 |
| wherein the processor is configured to determine the power headroom by subtracting the nominal maximum transmission power and the power that the apparatus would use if it did not apply maximum power limitations... | The accused LTE User Equipment allegedly calculates power headroom based on the LTE standard's defined formula, which the complaint contends is equivalent to the subtraction method recited in the claim. | ¶38, ¶39 | col. 9:20-24 |
- Identified Points of Contention: A key technical question is whether the power headroom reporting mechanism in the LTE standard implemented by the accused products actually generates "negative values." A defendant might argue that the standard uses a different encoding scheme (e.g., a mapped range of values) to indicate a power deficit, which is technically distinct from the claim's requirement of a report containing "negative values" derived from a specific subtraction.
V. Key Claim Terms for Construction
For the ’022 Patent
- The Term: "assigning a redundancy version sequence"
- Context and Importance: This term is central to the invention, as it describes the core action of determining the RV. The infringement analysis will depend on whether the process defined in the LTE standard is properly characterized as "assigning" a sequence according to the specific rules laid out in the patent.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification describes the overall goal as providing an "implicit redundancy version assignment" to mitigate certain problems. (’022 Patent, col. 7:4-6). A plaintiff may argue that any standardized, implicit method for determining the RV falls within this scope.
- Evidence for a Narrower Interpretation: The patent details a very specific process for the assignment, including detecting a window start and systematically excluding certain subframe types. (’022 Patent, Fig. 2; col. 7:16-30). A defendant may argue that the term is limited to this exact procedure, including the specific formula recited in Claim 6.
For the ’957 Patent
- The Term: "negative values" (of power headroom)
- Context and Importance: This term captures the point of novelty over prior art that allegedly only reported zero or positive headroom. Infringement hinges on whether the accused products' reports contain what can be legally and technically construed as "negative values."
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The background section frames the problem as the network not knowing about "missing power." (’957 Patent, col. 5:9-12). A plaintiff could argue any signal that quantifies this missing power, regardless of its numerical sign, constitutes a "negative value" in the context of the invention.
- Evidence for a Narrower Interpretation: The patent is specific, stating "the reported negative value indicates the missing power in dB" and that the reporting range could be extended to include values like "-23 dB." (’957 Patent, col. 5:22-24, col. 6:17-18). This supports a literal interpretation requiring an actual negative number or a value within a defined negative range, not just a flag or different type of indicator.
VI. Other Allegations
- Indirect Infringement: The complaint alleges both induced and contributory infringement. Inducement is based on allegations that Defendants provide user manuals, online support, and other instructional materials that encourage and instruct end-users to operate the accused LTE equipment in an infringing manner (Compl. ¶31, ¶43, ¶55). Contributory infringement is based on the allegation that the infringing functionalities are material to the inventions and are not staple articles of commerce suitable for substantial non-infringing use (Compl. ¶32, ¶44, ¶56).
- Willful Infringement: For the ’022 patent, willfulness is alleged based on pre-suit knowledge dating to at least December 2012, stemming from the patent's alleged status as a 3GPP standard-essential patent (SEP) and Defendants' participation in the standards body (Compl. ¶28-30). For the ’957 and ’472 patents, the complaint alleges knowledge "at least as early as service of this Complaint," supporting a claim for post-suit willful infringement only (Compl. ¶41, ¶53).
VII. Analyst’s Conclusion: Key Questions for the Case
- A central issue for all three patents will be one of technical congruence: does the specific implementation of the relevant 3GPP LTE standard, as practiced by the accused products, fall within the scope of the patent claims? The case may turn on whether the methods used in the standard for RV assignment, power headroom reporting, and CSI signaling are legally equivalent to the specific steps and definitions recited in the asserted claims.
- A key question for the ’022 patent will be one of essentiality and notice: the court will likely need to evaluate whether the patent is truly essential to the LTE standard and whether Defendants' membership in 3GPP is sufficient to establish pre-suit knowledge for the purposes of willful infringement.
- For the ’472 patent, the primary question will be one of patent viability: given that asserted claims were canceled in a post-filing IPR, the dispute will focus on whether any surviving claims are both valid over the prior art and infringed by the accused products, significantly narrowing the scope of the original allegations.