PTAB

IPR2018-01723

Cisco Systems Inc v. TracBeam LLC

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Wireless Communication System for Locating Mobile Stations
  • Brief Description: The ’484 patent describes systems and methods for estimating the location of a mobile station within a wireless communications network. The invention uses measurements from wireless signals communicated between mobile stations and fixed network base stations, utilizing a plurality of different wireless location estimators to determine a position.

3. Grounds for Unpatentability

Ground 1: Anticipation of Claim 25 - Claim 25 is anticipated by Sheffer under 35 U.S.C. §102.

  • Prior Art Relied Upon: Sheffer (Patent 5,844,522).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Sheffer, which discloses a system to locate mobile phones for emergency services, teaches every limitation of claim 25. Sheffer's system uses a central communication and dispatch center (CDC) that employs at least two independent techniques to estimate a phone's location: one based on azimuth triangulation from multiple cell sites (producing "area A") and another based on received signal strength information (RSSI) from a single cell site (producing "area B"). Petitioner contended these two distinct software-implemented techniques correspond to the claimed "at least two mobile station location evaluators." Sheffer was alleged to disclose obtaining these two separate location estimates, determining a final resulting position based on a comparison of them, and transmitting the final coordinates to a dispatched vehicle.
    • Key Aspects: The core of this argument relied on construing Sheffer's distinct calculation methods (azimuth triangulation vs. RSSI analysis) as separate "location evaluators," thereby meeting the claim's requirement for a plurality of such evaluators.

Ground 2: Obviousness of Claim 25 - Claim 25 is obvious over Sheffer in view of Cisneros under 35 U.S.C. §103.

  • Prior Art Relied Upon: Sheffer (’522 patent) and Cisneros (Patent 5,774,829).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground was presented as an alternative to Ground 1. Petitioner argued that if Sheffer was found not to explicitly teach making the final location "dependent on geographical information in each of the first and second location information," Cisneros supplied this missing element. Cisneros describes a navigation system that improves accuracy by combining position estimates from different, independent sources (e.g., uncoordinated beacon signals and GPS). Specifically, Cisneros teaches averaging or weighing the two position solutions according to their estimated quality to produce a final, more accurate result.
    • Motivation to Combine: A POSITA would combine Sheffer's multiple-estimate location system with Cisneros's method of averaging or weighing different location estimates. Sheffer emphasizes the need for "pinpoint accuracy" in emergency situations. A POSITA would recognize that combining the outputs from Sheffer's azimuth and RSSI techniques using the averaging method taught by Cisneros was a known and predictable way to improve the accuracy of the final determined position.
    • Expectation of Success: Petitioner asserted a high expectation of success, as both references are in the same field of mobile device location and address the common goal of improving positional accuracy. The combination represented the application of a known technique to a similar system to yield predictable results.

Ground 3: Obviousness of Claim 26 - Claim 26 is obvious over Sheffer and Cisneros, further in view of Sanderford under 35 U.S.C. §103.

  • Prior Art Relied Upon: Sheffer (’522 patent), Cisneros (’829 patent), and Sanderford (Patent 5,717,406).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground challenged dependent claim 26, which adds the step of obtaining location information from an additional (i.e., at least a third) location evaluator. Petitioner argued that Sanderford discloses such an additional evaluator. Sanderford teaches a system for estimating the location of a transmitter using a neural network that processes Time-of-Arrival (TOA) and Relative Time-of-Arrival (RTOA) data. This neural network processing device constitutes a third type of "location evaluator," distinct from Sheffer's azimuth and RSSI techniques.
    • Motivation to Combine: A POSITA would be motivated to add Sanderford’s neural network technique to the Sheffer/Cisneros system to further improve location accuracy, particularly in urban environments with significant multipath signal distortion. Sanderford explicitly teaches that its neural network can be trained to correct for multipath errors, a known problem that Sheffer acknowledges can cause erroneous readings. Therefore, integrating Sanderford’s technique would make the overall system more robust and reliable, especially for emergency calls originating from challenging signal environments.
    • Expectation of Success: Success would be expected because Sanderford’s system is designed for use in cellular telephone systems and is compatible with other known calculation algorithms like triangulation, making its integration with Sheffer’s system straightforward for a POSITA.

4. Key Claim Construction Positions

  • "mobile station location evaluator": Petitioner argued this term is a means-plus-function term governed by 35 U.S.C. §112, ¶ 6.
    • Function: "determining [a] mobile station location."
    • Structure: "a location hypothesizing model (FOM) implemented on or by a location center or mobile base station."
    • This construction was critical to Petitioner's arguments, as it allowed different software algorithms and computational models disclosed in the prior art (e.g., azimuth triangulation, RSSI analysis, neural network processing) to be identified as the structure corresponding to the claimed "evaluators."

5. Relief Requested

  • Petitioner requested the institution of an inter partes review and cancellation of claims 25 and 26 of the ’484 patent as unpatentable.