PTAB

IPR2018-01387

RPX Corp v. Vertical ConNECTon Technologies LLC

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1. Case Identification

2. Patent Overview

  • Title: System and Method for IP Handoff
  • Brief Description: The ’917 patent relates to systems and methods for network "handoffs" that allow mobile devices to roam between heterogeneous wireless networks, such as between an 802.11 Wireless Local Area Network (WLAN) and a General Packet Radio Service (GPRS) network. The invention purports to provide a seamless vertical handoff between different wireless technologies.

3. Grounds for Unpatentability

Ground 1: Obviousness over Natarajan - Claims 1-4, 6-10 are obvious over Natarajan.

  • Prior Art Relied Upon: Natarajan (Patent 6,993,335).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Natarajan discloses a Mobile IP (MIP) system for "seamless inter-technology handoff" that meets nearly all limitations of the challenged claims. Natarajan’s system includes a mobile node (MN) that connects to a network via a WLAN foreign agent (FAWLAN) and a WWAN foreign agent (FARAN), with a home agent (HA) tunneling data to the appropriate foreign agent. This structure was alleged to map directly to the system of independent claim 1. For method claim 9, Petitioner argued Natarajan describes establishing a WLAN connection, determining its signal strength has fallen below a threshold, and seamlessly moving the connection to a WWAN.
    • Motivation to Combine (for §103 grounds): This ground was asserted under 35 U.S.C. §103 primarily because Natarajan does not explicitly recite "executable code" for performing the handoff on the mobile node. Petitioner contended it would have been obvious for a person of ordinary skill in the art (POSITA) to implement the handoff logic described in Natarajan using executable code on the mobile node's processor, as this was a simple, inexpensive, and standard implementation method for such functionality at the time.
    • Expectation of Success (for §103 grounds): A POSITA would have had a high expectation of success in implementing the known handoff logic in software, as it was a routine and well-understood task.

Ground 2: Obviousness over Brewer - Claims 1-4, 6-7, 9-11 are obvious over Brewer.

  • Prior Art Relied Upon: Brewer (IEEE Personal Comm’ns (Oct. 1998)).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that Brewer, which arose from the UC-Berkeley "BARWAN project," discloses a seamless vertical handoff system built on Mobile IP. The system features a mobile host (MH) connecting to a network via base stations acting as foreign agents, including a WaveLAN (WLAN) base station and a Metricom Ricochet (WWAN) base station. A home agent tunnels data to the MH via the active foreign agent. Petitioner contended that Brewer's MH deciding when to hand off based on the presence or absence of beacon signals corresponds to determining if signal strength is "Strong" or "Weak," thus meeting the signal-strength-related limitations.
    • Motivation to Combine (for §103 grounds): Similar to the Natarajan ground, Brewer was presented under §103 because it did not explicitly mention "executable code." Petitioner argued that since Brewer's MH (a PalmPilot with a processor) performs the handoff, it would have been obvious to a POSITA to implement these functions using executable code.
    • Expectation of Success (for §103 grounds): A POSITA would have expected success in programming the described handoff logic onto the mobile host's processor, as this was standard practice.

Ground 3: Obviousness over Brewer and Sanmateu - Claims 2, 6, 9-11 are obvious over Brewer in view of Sanmateu.

  • Prior Art Relied Upon: Brewer (IEEE Personal Comm’ns (Oct. 1998)) and Sanmateu (Computer Networks: Int’l J. Computer Telecomm’ns Networking (Sept. 2002)).

  • Core Argument for this Ground:

    • Prior Art Mapping: This ground was intended to strengthen the argument for claims requiring specific signal strength monitoring. While Brewer teaches handoffs based on the binary presence or absence of beacon signals, Sanmateu teaches a more refined approach. Sanmateu discloses a "handover controller" that monitors the physical-layer WLAN signal level and initiates a handoff when the signal drops below a predefined threshold, improving performance.
    • Motivation to Combine (for §103 grounds): A POSITA would combine Sanmateu's specific, threshold-based signal strength monitoring with Brewer's vertical handoff system to improve handoff latency and create a smoother, more reliable user experience. Petitioner argued that because both references operate within the same Mobile IP context, their teachings are complementary, and improving performance is a recognized motivation in the art.
    • Expectation of Success (for §103 grounds): Success was expected because Brewer's mobile host already had access to signal strength information for horizontal handoffs; therefore, applying that same information to vertical handoffs as taught by Sanmateu would have been a straightforward implementation.

  • Additional Grounds: Petitioner asserted additional obviousness challenges, including combinations of Natarajan with Perkins (for FA buffering), RFC-3024 (for reverse tunneling), and Stevens (for TCP communications), and combinations of Brewer with RFC-3024 (reverse tunneling) and Pahlavan (using a GPRS WWAN).

4. Key Claim Construction Positions

  • "home agent" / "foreign agent": Petitioner argued these terms should be construed as comprising a Mobile IP (MIP) home agent and foreign agent, respectively, as defined in the open standard document RFC-2002. This construction was central to the petition's core theory that the ’917 patent is merely an implementation of this well-known standard and that the prior art references, which all operate within the same MIP framework, render its claims obvious.

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-11 of Patent 7,245,917 as unpatentable.