DCT
6:21-cv-00109
Tot Power Control SL v. T-Mobile US Inc
Key Events
Amended Complaint
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: TOT Power Control, SL. (Spain)
- Defendant: T-Mobile USA, Inc. (Delaware)
- Plaintiff’s Counsel: DINOVO PRICE LLP
- Case Identification: 6:21-cv-00109, W.D. Tex., 06/19/2025
- Venue Allegations: Plaintiff alleges venue is proper in the Western District of Texas because Defendant maintains a regular and established place of business in the district through its retail stores and by maintaining and controlling CDMA-based wireless network infrastructure.
- Core Dispute: Plaintiff alleges that Defendant’s WCDMA cellular network infrastructure infringes two patents related to methods for dynamically adjusting power control targets to improve network efficiency and call quality.
- Technical Context: Power control is a critical function in CDMA-based cellular networks, such as 3G/UMTS, used to manage interference between users, maintain signal quality, and maximize overall system capacity.
- Key Procedural History: The complaint does not reference any prior litigation, licensing history, or administrative proceedings concerning the patents-in-suit.
Case Timeline
| Date | Event |
|---|---|
| 2005-08-17 | Priority Date for '376 and '865 Patents |
| 2009-02-24 | '376 Patent Issue Date |
| 2009-05-12 | '865 Patent Issue Date |
| 2025-06-13 | Plaintiff served infringement contentions |
| 2025-06-19 | Amended Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 7,496,376 - Outer Loop Power Control Method and Apparatus for Wireless Communications Systems
The Invention Explained
- Problem Addressed: The patent addresses the slow response time of conventional outer loop power control (OLPC) systems in wireless networks ('376 Patent, col. 3:1-10). These systems typically rely on measuring the Block Error Rate (BLER), a process that is too slow to adapt efficiently to the rapidly changing signal conditions (fading) common in mobile environments, leading to wasted power and reduced network capacity (Compl. ¶12).
- The Patented Solution: The invention proposes a more dynamic "Outage-Based OLPC" method that supplements the standard BLER-based control ('376 Patent, col. 5:3-12). The system calculates "fading margins" based on "outage probabilities" and uses a "dynamic adjusting function" to map these faster-reacting metrics, along with the traditional BLER status, to a target Signal-to-Interference Ratio ("SIR_target"). This allows the system to adjust power levels more quickly and precisely in response to real-time channel conditions ('376 Patent, Abstract; col. 6:1-12; Fig. 7).
- Technical Importance: This approach aimed to improve the capacity and efficiency of 3G/WCDMA networks by making power control more adaptive and responsive than the standard-defined methods (Compl. ¶16).
Key Claims at a Glance
- The complaint asserts infringement of Claims 1 and 6, with specific allegations directed to independent apparatus Claim 6 (Compl. ¶26, ¶28).
- Claim 6 requires an apparatus with a programmable electronic device operable to perform several steps, including:
- Establishing a target block error rate ("BLER_target").
- Calculating an estimate of a received signal-to-interference ratio ("SIR_rec") and of fading parameters in the channel.
- Estimating "fading margins" associated with "outage probabilities."
- Indicating the status of data blocks based on a Cyclic Redundancy Code (CRC) check.
- Establishing a "SIR_target" for the outer loop based on the CRC status, the fading margins, and the "BLER_target" by means of a "dynamic adjusting function which performs a mapping" between quality criteria based on outage probabilities and the target block error rate.
U.S. Patent No. 7,532,865 - Outer Loop Power Control Method and Device for Wireless Communications Systems
The Invention Explained
- Problem Addressed: The patent addresses the "wind-up" problem in OLPC systems, which occurs when severe channel degradation causes the "SIR_target" to rise to an excessively high level ('865 Patent, col. 3:1-11). When channel conditions improve, conventional systems are very slow to reduce this inflated "SIR_target" back to an appropriate level, a process called "unwinding." This period of slow recovery causes unnecessary interference, wasting network capacity and degrading the quality of other connections (Compl. ¶12).
- The Patented Solution: The invention provides a method to accelerate the "unwinding" process ('865 Patent, col. 4:21-36). The method involves detecting the start of a wind-up event, managing the "SIR_target" during the event, and, critically, detecting the start of the unwinding process. Upon detecting the start of unwinding, the "SIR_target" is immediately modified to a value that matches the level it was at just before the wind-up event began. This rapid reset avoids the prolonged period of high interference associated with slow convergence ('865 Patent, Abstract; Fig. 4).
- Technical Importance: This technique was designed to allow a cellular network to recover quickly from severe fading events, thereby reducing interference, increasing system capacity, and improving connection quality (Compl. ¶19-20).
Key Claims at a Glance
- The complaint asserts infringement of Claims 1 and 5, with specific allegations directed to independent method Claim 1 (Compl. ¶43, ¶45).
- Claim 1 requires a method comprising steps, including:
- Setting a "SIR_target" that is close to the required SIR during normal operation.
- Detecting the start of an "outer loop wind-up."
- Setting a specific "SIR_target" during the wind-up.
- Detecting the start of an "outer loop unwinding."
- Modifying the "SIR_target" at the start of the unwinding to "match it to the outer loop power control in normal mode just prior to the start of the outer loop wind up."
III. The Accused Instrumentality
Product Identification
- T-Mobile's WCDMA-based wireless networks, specifically the Base Transmission Stations ("BTS") and their constituent components, including Radio Network Controllers ("RNC") and Node-Bs (Compl. ¶28, ¶45).
Functionality and Market Context
- The complaint alleges that these network components are supplied by intervenors Nokia and Ericsson and perform the power control functions for T-Mobile's WCDMA network (Compl. ¶28, ¶45). The accused functionality includes managing both inner and outer loop power control processes as required by the 3GPP UMTS standard (Compl. ¶29). This involves measuring the received Signal-to-Interference Ratio ("SIR_Rec"), comparing it to a target value ("SIR_Target"), and adjusting the "SIR_Target" based on network performance indicators, such as block/frame errors indicated by Cyclic Redundancy Checks (CRC) (Compl. ¶31, ¶34, ¶47). Plaintiff alleges this standards-based operation also implements its patented technologies, leading to significant capacity gains (Compl. ¶20).
IV. Analysis of Infringement Allegations
'376 Patent Infringement Allegations
| Claim Element (from Independent Claim 6) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| An outer loop power control apparatus... comprising at least one programmable electronic device... operable to... perform the steps of: | The WCDMA BTS are comprised of processors that manage inner and outer loop power control. | ¶29 | col. 15:30-34 |
| establishing a target block error rate (BLERtarget) | The WCDMA BTS maintain a configurable parameter for the Block Error Rate Target, as required by the 3GPP UMTS Standard. | ¶30 | col. 15:35-36 |
| calculating an estimate (701) of a desired signal to interference ratio (SIRrec) and of some fading parameters in a channel (706) | The WCDMA BTS measure the received SIR value ("SIR_Rec") and estimate fading by comparing the measured "SIR_Rec" values to "SIR_Target" values over time. | ¶31-32 | col. 15:37-42 |
| estimating some fading margins (M1, M2, ...MN) associated with some outage probabilities... | The WCDMA BTS allegedly use a collection of error values to determine a distribution, from which a fading margin associated with an outage probability is calculated. A diagram illustrates how a "Fading Margin" is derived from the distribution of SIR error values relative to an "Outage Probability" threshold (Compl. p. 14). | ¶33 | col. 15:43-46 |
| indicating a status of the data blocks (707) based on the checking of a Cyclic Redundancy Code (CRC) | The WCDMA BTS adjust the "SIR_Target" value based on block/frame errors indicated by CRC checks, per the 3GPP UMTS Standard. | ¶34 | col. 15:47-49 |
| establishing a target desired signal to interference ratio (SIRtarget)... by means of a dynamic adjusting function which performs a mapping between a quality criterion based on the outage probabilities... and the quality criterion based on the target block error rate (BLERtarget) | The WCDMA BTS allegedly adjust the "SIR_Target" value using both the BLER-based mechanism (from CRC errors) and the calculated fading margin values. | ¶35 | col. 15:49-68 |
- Identified Points of Contention:
- Scope Questions: The analysis may turn on whether the accused system's alleged act of comparing "SIR_Rec" to "SIR_Target" over time meets the claim requirement of "calculating some fading parameters." A further question is whether using the resulting error distribution to derive a margin, as depicted in the complaint's diagram (Compl. p. 14), constitutes "estimating some fading margins associated with some outage probabilities" as contemplated by the patent.
- Technical Questions: A key technical question is whether the accused BTS performs a "mapping" via a "dynamic adjusting function" as claimed, or if it merely applies two separate and conventional adjustment mechanisms (one based on BLER and another based on an SIR error margin) that do not interact in the manner required by the claim.
'865 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| estimating a desired signal to interference ratio received (SIRrec)... | The WCDMA BTS measure the received SIR value as part of the standard outer loop power control mechanism. | ¶46 | col. 9:48-51 |
| setting a desired signal to interference ratio target (SIRtarget) that is close to a signal to interference ratio required (SIR) during the normal mode... | The WCDMA BTS adjust the "SIR_Target" value based on block/frame errors indicated by CRC checks. A graph illustrates the standard method of adjusting the "SIR_Target" value, showing a large increase after a block error followed by gradual decreases for correct blocks (Compl. p. 6). | ¶47 | col. 9:52-55 |
| detecting a start (402) of the outer loop wind-up | The WCDMA BTS detect a "wind-up" condition based on repeated CRC block errors, frequent increases in "SIR_Target", and repeated commands to increase power. | ¶48 | col. 9:56 |
| setting a specific desired signal to interference ratio target (SIRtarget) during the outer loop wind-up | The WCDMA BTS limit the increases in the "SIR_Target" value, capping it at a predetermined value during the "wind-up" condition. | ¶49 | col. 9:57-59 |
| detecting a start (403) of the outer loop unwinding, wherein the... SIRtarget is modified... to match it to the outer loop power control in normal mode just prior to the start of the outer loop wind up | The WCDMA BTS detect the end of the "wind-up" condition based on the cessation of repeated CRC block errors and then adjust the "SIR_Target" to a value consistent with what it was before the "wind-up" began. | ¶50 | col. 9:59-10:2 |
- Identified Points of Contention:
- Scope Questions: The dispute may focus on whether detecting the "cessation of repeated CRC block errors" satisfies the claim limitation of "detecting a start (403) of the outer loop unwinding," or if the patent requires a more specific affirmative detection of channel recovery.
- Technical Questions: A central question will be whether the accused system's post-wind-up adjustment of the "SIR_Target" constitutes a "match" to the value "just prior to the start of the outer loop wind up" as claimed, or if it is a different type of reset algorithm that does not meet this specific limitation.
V. Key Claim Terms for Construction
- Patent: '376 Patent
- The Term: "dynamic adjusting function which performs a mapping"
- Context and Importance: This term is central to the invention of the '376 Patent, defining the novel mechanism for combining different quality metrics. The case may depend on whether the accused system's algorithm, which allegedly uses both BLER and fading margin inputs, qualifies as this specific type of "function."
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification states the function "consists preferentially of a neural network," which suggests that other types of functions are also contemplated ('376 Patent, col. 6:15-17). This may support an interpretation covering any algorithm that takes the claimed inputs to produce the "SIR_target" output.
- Evidence for a Narrower Interpretation: The patent provides a detailed description and figure of a specific two-layer neural network as the preferred embodiment for implementing the function ('376 Patent, col. 6:30-51; Fig. 5). This detailed disclosure could be used to argue that the term is limited to such a structure or its technical equivalent, rather than any generic combination of inputs.
- Patent: '865 Patent
- The Term: "detecting a start (403) of the outer loop unwinding"
- Context and Importance: This is the triggering event for the patent's core technical contribution—the rapid reset of "SIR_target". Infringement hinges on whether the accused BTS performs this specific detection step as claimed.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The patent describes the unwinding process generally as what occurs "after the end of the condition described above, that is, after the wind-up" ('865 Patent, col. 3:25-28). This language may support the plaintiff's allegation that detecting the "cessation of repeated CRC block errors" (Compl. ¶50)—the end of the condition causing the wind-up—is sufficient.
- Evidence for a Narrower Interpretation: The patent figures distinguish the start of wind-up (402) from the start of unwinding (403), depicting the latter as the point where the channel begins to recover and the measured SIR starts to rise again ('865 Patent, Fig. 4). This could support an argument that the claim requires an active detection of channel improvement, not merely the absence of further errors.
VI. Other Allegations
- Willful Infringement: The complaint alleges willful infringement for both patents based on Defendant’s continued infringement after gaining knowledge of the patents, at the latest, from the filing and service of the complaint (Compl. ¶38-40, ¶53-55).
VII. Analyst’s Conclusion: Key Questions for the Case
- A central issue will be one of technical equivalence: do the standards-based power control mechanisms allegedly used by T-Mobile, which rely on comparing "SIR_Rec" to "SIR_Target" and reacting to CRC errors, perform the specific, multi-step functions of "calculating... fading margins" and executing a "dynamic adjusting function" as required by the '376 patent, or is there a fundamental mismatch in technical operation?
- A key evidentiary question will be one of event detection: for the '865 patent, does the accused system’s alleged detection of a "cessation of repeated CRC block errors" meet the specific claim requirement of "detecting a start... of the outer loop unwinding," and does its subsequent "SIR_Target" adjustment constitute a "match" to the pre-wind-up value, or do these terms require a more precise functionality not present in the accused systems?