PTAB

IPR2018-01725

Cisco Systems Inc v. TracBeam LLC

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Gateway and Hybrid Solutions for Wireless Location
  • Brief Description: The ’525 patent discloses methods for locating a mobile unit using wireless communications data. The core method involves obtaining a first location estimate using a first technique, obtaining a second location estimate using a second technique involving "pattern recognizers," and then determining a final, resulting location estimate by either preferring one estimate over the other or combining them.

3. Grounds for Unpatentability

Ground 1: Obviousness over Sheffer, Tayloe, and Sanderford - Claims 1 and 6 are obvious over Sheffer in view of Tayloe and further in view of Sanderford.

  • Prior Art Relied Upon: Sheffer (Patent 5,844,522), Tayloe (Patent 5,023,900), and Sanderford (Patent 5,717,406).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner argued that Sheffer discloses the fundamental framework of the challenged claims. Sheffer teaches a system for locating a mobile phone by generating multiple, independent location estimates and then comparing them to select a final position with an associated confidence level. Specifically, Sheffer discloses a "first location technique" based on calculating a probable area using active cell site data and a "second location technique" using azimuth triangulation from multiple cell sites.

    The combination with Tayloe was argued to render obvious the limitations related to determining the geographical area for the first location estimate. Sheffer’s first technique relies on an idealized, predetermined coverage area for a cell site. Petitioner asserted that Tayloe teaches a known method for improving this by having the mobile unit itself measure and report signal strengths from nearby base stations to map the actual radio coverage boundaries.

    The further combination with Sanderford was argued to supply the claimed "pattern recognizer" and related limitations for the second location estimate. Sheffer acknowledges that its azimuth triangulation method is unreliable in environments with significant signal reflection. Sanderford addresses this exact problem by teaching the use of a neural network (which Petitioner argued is a type of "pattern recognizer") to analyze signal characteristics, including multipath reflections, and generate an accurate location estimate. Petitioner contended that Sanderford’s neural network, when supplied with data like azimuth and RSSI from Sheffer’s system, directly teaches obtaining a second location estimate using a pattern recognizer that is dependent on multipath patterns.

    Finally, Petitioner argued Sheffer’s process of comparing its different estimates (e.g., azimuth vs. cell site area) to select the most likely location and assign a confidence level meets the limitation of determining which of the first and second location estimates is preferred for the resulting estimate.

    • Motivation to Combine: Petitioner asserted a person of ordinary skill in the art (POSITA) would combine Tayloe with Sheffer to improve the accuracy of Sheffer’s first location technique. Tayloe provided a known, suitable technique for more accurately determining the cell coverage boundaries that Sheffer’s method relied upon. A POSITA would further combine Sanderford to solve a known problem explicitly identified in Sheffer—the inaccuracy of azimuth-based location in reflection-prone urban environments. Sanderford’s neural network technique, which uses multipath reflections to improve accuracy, directly addresses this deficiency.

    • Expectation of Success: A POSITA would have had a reasonable expectation of success in combining these references because they all relate to the same field of cellular communication and location-finding technology and address interrelated and well-known technical challenges.

4. Key Claim Construction Positions

  • "pattern recognizers": Petitioner argued this term is subject to 35 U.S.C. §112, ¶ 6 as a means-plus-function term. The proposed function was "estimating a location of a mobile unit M using a pattern recognition technique." The corresponding structure disclosed in the ’525 patent specification was argued to be a "location hypothesizing model (FOM) implemented on or by a location center or mobile base station," which could include artificial neural networks. This construction was critical for mapping the neural network taught by Sanderford to this claim limitation.

  • "at least one of the following (i) and (ii)": Petitioner argued that the plain and ordinary meaning of this phrase is "at least one of (i) or at least one of (ii)." This construction is important because it allows Petitioner to prove obviousness by showing the prior art teaches performing step (i)—determining which estimate is preferred—without needing to also show that the art teaches performing step (ii)—combining the estimates. Petitioner’s primary argument relied on Sheffer’s disclosure of preferring one estimate over another.

5. Relief Requested

  • Petitioner requested that the Board institute an inter partes review (IPR) for claims 1 and 6 of the ’525 patent and cancel these claims as unpatentable.