Cobblestone Wireless LLC v. T-Mobile USA Inc

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Cobblestone Wireless, LLC (Texas)
  • Defendant: T-Mobile USA, Inc. (Delaware)
  • Plaintiff’s Counsel: Russ August & Kabat
• Case Identification: 2:23-cv-00381, E.D. Tex., 08/25/2023
• Venue Allegations: Plaintiff alleges venue is proper in the Eastern District of Texas because Defendant has regular and established places of business in the district, has committed acts of infringement there, and operates cellular infrastructure (base stations) that provide 4G and 5G services within the district.
• Core Dispute: Plaintiff alleges that Defendant’s cellular network infrastructure, mobile devices, and services that utilize 3GPP carrier aggregation infringe a patent related to methods for simultaneously transmitting information over different radio frequency (RF) ranges.
• Technical Context: The technology concerns methods for increasing data throughput and reliability in wireless systems by concurrently using multiple distinct frequency bands, a core concept underlying modern high-speed cellular technologies like 4G LTE and 5G.
• Key Procedural History: The complaint does not mention any prior litigation, Inter Partes Review (IPR) proceedings, or licensing history related to the patent-in-suit.

Case Timeline

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

U.S. Patent No. 7,924,802 - "Wireless Communication Systems and Methods"

• Patent Identification: U.S. Patent No. 7,924,802, "Wireless Communication Systems and Methods", issued April 12, 2011.

The Invention Explained

• Problem Addressed: The patent describes a limitation in conventional wireless transmitters where data transmission is confined to a single RF channel centered around a specific frequency, which limits the total amount of information that can be sent (throughput) ('802 Patent, col. 1:29-39).
• The Patented Solution: The invention proposes a method and system for transmitting information simultaneously across two or more distinct frequency ranges using a single transmitter ('802 Patent, col. 2:58-65). As illustrated in one embodiment, this involves processing two separate digital data streams, converting them to analog signals, up-converting each to a different RF center frequency, and then combining the signals before they are amplified by a single power amplifier and transmitted via a single antenna (’802 Patent, col. 6:10-21, Fig. 2). This allows for either sending more data at once or sending the same data redundantly on different frequencies to improve reliability.
• Technical Importance: This technique of aggregating spectrum enables significantly higher data rates and more robust connections, forming a foundational principle for technologies like carrier aggregation, which is a key feature of 4G LTE and 5G cellular standards ('802 Patent, col. 1:50-57).

Key Claims at a Glance

• The complaint asserts infringement of at least independent Claim 1 (Compl. ¶12, ¶13, ¶14).
• The essential elements of independent Claim 1 are:
  • A method of transmitting information in a wireless communication channel comprising:
  • transmitting first information across a first frequency range using a wireless transmitter, the first frequency range having a first center frequency, a first highest frequency, and a first lowest frequency; and
  • simultaneously transmitting second information across a second frequency range using the same wireless transmitter, the second frequency range having a second center frequency greater than the first center frequency, a second highest frequency, and a second lowest frequency.
• The complaint does not explicitly reserve the right to assert other claims, but its infringement allegations are framed as being for "at least Claim 1" (Compl. ¶12).

III. The Accused Instrumentality

Product Identification

The accused instrumentalities are T-Mobile’s "cellular base stations, mobile products, and services that support 3GPP carrier aggregation" (Compl. ¶12). This includes T-Mobile's 4G and 5G network infrastructure and compatible end-user devices such as phones and tablets (Compl. ¶4, ¶9).

Functionality and Market Context

The complaint alleges that the accused products and services implement carrier aggregation, a standardized feature in 4G and 5G communications that allows a device to connect to multiple frequency bands, or "component carriers," at the same time (Compl. ¶12). This functionality is used to increase peak data rates for users by combining the bandwidth of the different frequency bands. The complaint alleges these services are offered to customers throughout the Eastern District of Texas (Compl. ¶9).

No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

The complaint references a claim chart attached as Exhibit 2, which was not included in the public filing (Compl. ¶15). Therefore, a tabular analysis cannot be performed. The narrative theory of infringement presented in the complaint is that T-Mobile's products and services that use 3GPP carrier aggregation practice the method of Claim 1 of the ’802 Patent (Compl. ¶12).

The core of the allegation is that carrier aggregation technology, by its nature, involves transmitting a first set of data ("first information") on a first frequency band ("first frequency range") while simultaneously transmitting a second set of data ("second information") on a second frequency band ("second frequency range") using the same device or base station ("the same wireless transmitter"). The complaint alleges that this operation directly infringes, either literally or under the doctrine of equivalents, the steps recited in Claim 1 (Compl. ¶12).

Identified Points of Contention

• Scope Questions: A central dispute may concern the scope of the term "using the same wireless transmitter." The patent’s embodiment depicts two signal paths converging into a single power amplifier (’802 Patent, Fig. 2). The case may turn on whether modern cellular base stations or mobile devices, which may use multiple integrated radio-frequency front-end modules, can be considered the "same wireless transmitter" as contemplated by the patent.
• Technical Questions: The meaning of "simultaneously transmitting" may be contested. The question is whether the scheduling of data packets across different component carriers in a 4G/5G system, which occurs within standardized transmission time intervals, meets the "simultaneously" limitation as it would have been understood at the time of the invention.

V. Key Claim Terms for Construction

The Term: "the same wireless transmitter" (from Claim 1)

Context and Importance

The definition of this term is critical because modern 4G/5G base stations and user equipment are architecturally complex. Whether the accused systems, which may contain multiple radio chains, meet this limitation will likely be a primary point of non-infringement argument. Practitioners may focus on this term because the patent’s preferred embodiment shows a specific architecture where two signals are combined just before a single power amplifier, which may not map directly onto the architecture of the accused products.

Intrinsic Evidence for Interpretation

• Evidence for a Broader Interpretation: The claim language recites "a wireless transmitter" without further architectural limitations. The summary of the invention also broadly describes the method as "using the same wireless transmitter" without restricting it to a single power amplifier architecture in every instance, which may support an interpretation that covers a single, integrated device performing the transmission function (e.g., a smartphone) ('802 Patent, col. 2:63-64).
• Evidence for a Narrower Interpretation: Figure 2, which illustrates an embodiment of the invention, explicitly shows two distinct up-conversion paths (205, 206) that are combined before a single power amplifier (208) and antenna (209). Language stating that the first and second signals "are transmitted using the same power amplifier" could be used to argue that the claimed "transmitter" requires this shared-component architecture ('802 Patent, col. 2:10-12).

VI. Other Allegations

Indirect Infringement

The complaint alleges induced infringement, stating that T-Mobile "actively encourage[s] and instruct[s] its customers and end users (for example, through user manuals and online instruction materials on its website)" to use the accused products in an infringing manner (i.e., by using the network's carrier aggregation features) (Compl. ¶13). It is alleged that T-Mobile does so with the knowledge and intent that its customers will directly infringe the ’802 Patent.

Willful Infringement

The complaint alleges knowledge of the ’802 Patent and its infringement "[t]hrough at least the filing and service of this Complaint" (Compl. ¶13). This allegation appears to establish a basis for post-suit willfulness but does not plead specific facts indicating that T-Mobile had knowledge of the patent before the lawsuit was filed.

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

1. A core issue will be one of claim scope and technical translation: Can the term "the same wireless transmitter", as described and illustrated in a 2008-filed patent, be construed to read on the distributed and modular hardware architecture of modern 4G/5G base stations and user devices that implement carrier aggregation? The outcome may depend on whether the claim is interpreted to require a specific component arrangement, such as a single shared power amplifier.
2. A second key question will be evidentiary and factual: Assuming a favorable claim construction for the plaintiff, does the specific implementation of 3GPP carrier aggregation in T-Mobile's network and on accused devices meet every limitation of Claim 1? This will require a detailed technical analysis of how data is processed, scheduled, and transmitted across multiple frequency bands in the accused systems, and whether that functionality aligns with the patent's description of "simultaneously transmitting" distinct information.