DCT
2:23-cv-00454
Cobblestone Wireless LLC v. Cisco Systems Inc
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Cobblestone Wireless, LLC (Texas)
- Defendant: Cisco Systems, Inc. (Delaware)
- Plaintiff’s Counsel: Russ August & Kabat
- Case Identification: 2:23-cv-00454, E.D. Tex., 09/29/2023
- Venue Allegations: Plaintiff alleges venue is proper in the Eastern District of Texas because Defendant has committed acts of infringement and maintains regular and established places of business within the district.
- Core Dispute: Plaintiff alleges that Defendant’s Wi-Fi products capable of operating in an 80+80 MHz channel width mode infringe a patent related to simultaneously transmitting information over two different frequency ranges using a single transmitter.
- Technical Context: The technology concerns methods for increasing wireless data throughput by aggregating non-contiguous blocks of radio-frequency spectrum, a technique used in modern Wi-Fi standards.
- Key Procedural History: The complaint states that Plaintiff owns the patent-in-suit by assignment. No other significant procedural events, such as prior litigation or administrative proceedings, are mentioned.
Case Timeline
| Date | Event |
|---|---|
| 2008-01-23 | ’802 Patent Priority Date |
| 2011-04-12 | ’802 Patent Issue Date |
| 2023-09-29 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 7,924,802 - “Wireless Communication Systems and Methods,” issued April 12, 2011
The Invention Explained
- Problem Addressed: The patent's background describes limitations in conventional wireless systems where a transmitter is typically confined to sending data around a single center frequency, which limits data capacity ('802 Patent, col. 1:30-39). Additionally, regulatory power limits per unit of bandwidth can constrain the reliability and range of a transmission ('802 Patent, col. 1:40-48).
- The Patented Solution: The invention proposes a system and method to transmit information simultaneously across two distinct frequency ranges using a single wireless transmitter ('802 Patent, col. 2:1-6). As depicted in embodiments like Figure 2, this can be achieved by processing two separate data streams, up-converting each to a different radio frequency (f1, f2), and then combining them before they are amplified by a single, wide-bandwidth power amplifier for transmission via a single antenna ('802 Patent, col. 6:21-63, Fig. 2).
- Technical Importance: This architecture provides a method for aggregating spectrum, including non-contiguous channels, to increase overall data throughput or to improve reliability by transmitting the same data redundantly over different frequencies ('802 Patent, col. 10:1-4).
Key Claims at a Glance
- The complaint asserts at least independent claim 1 ('802 Patent, Compl. ¶10).
- 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; 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.
- The complaint does not explicitly assert other claims but makes general allegations of infringement.
III. The Accused Instrumentality
Product Identification
The complaint identifies the "Accused Instrumentalities" as Cisco's "802.11ac and 802.11ax-compliant station and access point products that support 80+80 MHz channel width," providing the Cisco-Meraki MR53 as a representative example (Compl. ¶10).
Functionality and Market Context
The accused functionality is the products' ability to operate in "80+80 MHz channel width" mode (Compl. ¶10). This is a feature standardized in the IEEE 802.11ac and subsequent Wi-Fi protocols, where a device transmits over two separate, non-contiguous 80 MHz channels concurrently to achieve higher data rates. The complaint does not provide further details on the products' market context beyond their identification as Cisco products.
IV. Analysis of Infringement Allegations
No probative visual evidence provided in complaint. The complaint references a claim chart in an external exhibit not included with the pleading (Compl. ¶13). The infringement theory is therefore summarized below based on the complaint's narrative allegations.
’802 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A method of transmitting information in a wireless communication channel comprising: transmitting first information across a first frequency range using a wireless transmitter... | The complaint alleges that Cisco's products, when operating in 80+80 MHz mode, transmit data over a first 80 MHz frequency channel. | ¶10 | col. 14:60-65 |
| 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... | The complaint alleges that Cisco's products, in the same 80+80 MHz mode operation, simultaneously transmit data over a second, non-contiguous 80 MHz frequency channel using the same device (e.g., the Cisco-Meraki MR53). | ¶10 | col. 14:61-col. 15:7 |
Identified Points of Contention
- Scope Questions: A central dispute may arise over the proper construction of the term "wireless transmitter." The question for the court will be whether the integrated chipset architecture in Cisco's 802.11ac/ax products constitutes the "same wireless transmitter" as contemplated by the patent, or if the defense can distinguish it from the embodiments described in the specification, such as the shared power amplifier architecture.
- Technical Questions: The infringement allegation rests on the functionality of the 802.11ac/ax standard's "80+80 MHz" mode. A technical question will be whether the actual operation of this mode in the accused products meets every limitation of the asserted claims, including the "simultaneously transmitting" requirement, as that term is construed in the context of the '802 patent.
V. Key Claim Terms for Construction
The Term: "wireless transmitter"
- Context and Importance: The definition of this term is critical. Infringement hinges on whether the accused Cisco products, which perform multi-channel transmission, are considered a single "wireless transmitter" under the patent's definition. Practitioners may focus on this term to determine if the claim reads on a general functional unit or requires a specific hardware configuration.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The claim language itself is functional ("A method of transmitting...using a wireless transmitter"), which may support an interpretation covering any single device (e.g., an access point) that performs the claimed steps, regardless of its internal components ('802 Patent, col. 14:60-61).
- Evidence for a Narrower Interpretation: The specification repeatedly illustrates embodiments where two distinct signal paths are combined before a single power amplifier and a single antenna ('802 Patent, Fig. 2; col. 6:58-63). This could support an argument that the "transmitter" of the invention is defined by this shared-component architecture.
The Term: "simultaneously transmitting"
- Context and Importance: This term's construction will be key to determining whether the timing of the two 80 MHz channel transmissions in the accused products meets the claim limitation.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification discusses transmitting different OFDM symbols "during a first time slot" across the two different frequency ranges, suggesting "simultaneously" refers to transmission within the same timing interval or data packet, not necessarily at the exact same infinitesimal moment ('802 Patent, col. 2:18-24).
- Evidence for a Narrower Interpretation: A party could argue for a more literal, instantaneous meaning, although this may be difficult to maintain given the context of packet-based digital communications described in the patent.
VI. Other Allegations
Indirect Infringement
The complaint alleges induced infringement, stating that Cisco encourages infringement by providing customers with "user manuals and online instruction materials" to use the accused 80+80 MHz functionality (Compl. ¶11). It also pleads contributory infringement, alleging the accused products are "especially made or adapted to infringe" and are not "staple articles or commodities of commerce suitable for non-infringing use" (Compl. ¶12). This latter point may raise a defense, as the accused devices have multiple standard-compliant, single-channel modes of operation that would be non-infringing.
Willful Infringement
The complaint alleges Cisco has knowledge of the '802 patent "Through at least the filing and service of this Complaint" (Compl. ¶11). This allegation supports a claim for post-suit willfulness, but the complaint does not allege any facts that would support pre-suit knowledge or willfulness.
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of architectural scope: can the term "wireless transmitter", as used in Claim 1, be construed to cover the integrated system-on-a-chip architecture of a modern 802.11ac/ax access point, or is its meaning limited by the specification's more specific embodiments that depict two signal paths converging into a single power amplifier?
- A second key question will relate to the intersection of the patent and an industry standard: does the broad method claimed in the '802 patent read on the specific "80+80 MHz" operational mode later defined in the IEEE 802.11ac standard? The case will likely involve determining whether the accused products are merely practicing a public standard or if that standard's functionality is encompassed by the patent's prior claims.
- A significant evidentiary question for indirect infringement will be one of substantial non-infringing use: can Cisco demonstrate that its products, despite supporting the accused 80+80 MHz mode, have commercially significant and readily available uses that do not practice the patented method (e.g., single-channel operation), thereby challenging the claim for contributory infringement?