PTAB

IPR2025-01569

Cisco Systems Inc v. Dynamic Mesh Networks Inc

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Wireless Multiple Radio Mesh
  • Brief Description: The ’385 patent describes a wireless mesh network where a mobile child node uses multiple radios to maintain connectivity. The technology involves a dedicated scanning radio to identify potential new parent nodes, while two or more relay radios handle data traffic, and packets are buffered at both the child and parent nodes during the scanning process to prevent data loss.

3. Grounds for Unpatentability

Ground 1: Obviousness over Castagnoli and Bohm - Claims 2 and 3 are obvious over Castagnoli in view of Bohm.

  • Prior Art Relied Upon: Castagnoli (Application # 2006/0215583) and Bohm (Patent 5,982,780).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Castagnoli disclosed the core elements of the challenged claims, including a wireless mesh network with multi-radio nodes. Castagnoli taught that nodes "typically" use a dedicated radio for monitoring the RF environment (scanning), one or more radios to service the backhaul (relay radios), and that these radios can operate on different, non-interfering channels for upstream and downstream traffic. Castagnoli further disclosed that during neighbor discovery (sampling), nodes are unavailable for regular traffic, and it taught buffering packets in transmit/receive queues to manage data flow. The key element missing from Castagnoli was the specific coordination of sampling times using tokens sent in a round-robin manner. Bohm supplied this missing element by teaching a network that coordinates data transmission among nodes using tokens associated with specific data time slots, where a central controller manages and distributes the tokens to avoid conflicts.
    • Motivation to Combine: A POSITA would have been motivated to combine the references as a simple substitution of a known element for a predictable result. Petitioner asserted that a POSITA would have substituted Bohm's well-known token-based coordination mechanism for Castagnoli's more general "packet collision avoidance mechanism." This would have been done to obtain the predictable result of avoiding interference between multiple child nodes when they perform neighbor discovery, a known problem in time-scheduled networks.
    • Expectation of Success: A POSITA would have had a high expectation of success because Bohm explicitly taught that its "token protocol guarantees the slot access to be conflict free." Applying this established coordination method to the time-slotted system of Castagnoli would predictably improve interference avoidance.

Ground 2: Obviousness over Castagnoli, Bohm, and Liu - Claim 1 is obvious over Castagnoli and Bohm in view of Liu.

  • Prior Art Relied Upon: Castagnoli (Application # 2006/0215583), Bohm (Patent 5,982,780), and Liu (Application # 2006/0198346).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground built upon the combination of Castagnoli and Bohm from Ground 1 to address the limitations of method claim 1. The key additional limitation in claim 1 was that "at least one mesh node is moving sufficiently rapidly that it may lose connectivity with its current parent mesh node." While Castagnoli disclosed maintaining connections with "mobile stations," Petitioner argued Liu provided more explicit teachings on this topic. Liu addressed the specific problem of nodes in an ad-hoc network that "move or travel constantly" and "may acquire a new neighbor or lose an existing neighbor," particularly when they "move at a fast rate" or "move[] away beyond a radio propagation range" of another node.
    • Motivation to Combine: A POSITA would have been motivated to modify the Castagnoli/Bohm system with the teachings of Liu to address the known and common problem of mobile nodes in a wireless network. Castagnoli taught that parent-child relationships can change due to various factors, and Liu provided node mobility as another explicit, well-understood factor causing such changes. Combining the teachings was a straightforward application of a known solution (managing fast-moving nodes as in Liu) to improve the operation of Castagnoli's mesh network, yielding the predictable result of a system capable of handling rapidly moving nodes that risk losing connectivity.
    • Expectation of Success: The combination was a predictable aggregation of prior art elements. Since both Castagnoli and Liu dealt with mobile nodes and changing network topologies, a POSITA would expect that applying Liu's specific teachings on rapid movement to Castagnoli's system would successfully address the challenges of maintaining connectivity.

4. Key Claim Construction Positions

  • "at a first point in time" (Claim 3): Petitioner proposed that the three separate recitations of this phrase in claim 3 should be construed to refer to the same point in time. This construction is necessary to give meaning to all claim terms and avoid rendering the recitations superfluous, as any action inherently occurs at a point in time. Under this interpretation, the first relay radio, second relay radio, and dedicated scanning radio must all be operating concurrently.

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-3 of the ’385 patent as unpatentable under 35 U.S.C. §103.