PTAB

IPR2014-01219

Sonitor Technologies Inc v. Centrak Inc

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: METHODS AND SYSTEMS FOR SYNCHRONIZED ULTRASONIC REAL TIME LOCATION
  • Brief Description: The ’909 patent discloses a real-time location system (RTLS) for tracking mobile tags. The system uses a central engine to synchronize a network of ceiling-mounted readers, which transmit synchronization signals containing timing information. Tags receive these signals, await a specific time or event, and then transmit an ultrasonic signal, which is detected by the readers to determine the tag’s precise location based on time-of-flight calculations.

3. Grounds for Unpatentability

Ground 1: Obviousness over Maloney and Enzmann - Claims 1-6, 8-13, and 15-26 are obvious over Maloney in view of Enzmann.

  • Prior Art Relied Upon: Maloney (Patent 6,127,928) and Enzmann (Application # 2005/0136927).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Maloney discloses a complete RTLS that meets nearly all limitations of the challenged claims, including a central controller, readers (Cell Controllers), and tags that use synchronized radio frequency (RF) and ultrasonic signals for time-of-flight location. Maloney’s system involves readers transmitting an RF signal to a tag, which then responds with an ultrasonic pulse. Petitioner asserted the only missing element is the tag explicitly "awaiting receipt of the synchronization signal" before transmitting. Enzmann was argued to supply this limitation by disclosing a power-saving technique for mobile devices where the device remains in a low-power state and periodically enters a "listening mode" to await signals from a base station.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine Maloney's RTLS with Enzmann's power-saving listening protocol to improve the battery life of the mobile tags. Extending battery performance was a primary and well-understood design goal for such portable devices, making the integration of a known power-saving method a predictable design choice.
    • Expectation of Success: The implementation of a listening window or sleep/wake cycle was a conventional technique in wireless communications. A POSITA would have had a high expectation of success in applying Enzmann’s established power management strategy to the tags in Maloney’s system without undue experimentation.

Ground 2: Obviousness over Maloney and Alternative Power-Saving Art - Claims 1-6, 8-13, and 15-26 are obvious over Maloney in view of Dorenbosch, Chaskar, or Willhoff.

  • Prior Art Relied Upon: Maloney (Patent 6,127,928), Dorenbosch (Application # 2005/0048977), Chaskar (Application # 2004/0137902), and Willhoff (Patent 6,049,715).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner presented Dorenbosch, Chaskar, and Willhoff as alternative references to Enzmann, each teaching analogous power-saving techniques that would supply the "awaiting" limitation missing from Maloney. Dorenbosch discloses a mobile station entering a dormant state and waking periodically to monitor a control channel for pages. Chaskar teaches a wireless device using a sleep mode and waking to listen for a beacon from an access point. Willhoff similarly discloses a remote unit that deactivates its receiver and periodically reactivates it to check for incoming signals. Petitioner asserted that any of these well-known sleep/wake protocols would render the claimed invention obvious when applied to Maloney's base system.
    • Motivation to Combine: The motivation to combine Maloney with any of these alternative references was identical to the motivation for combining with Enzmann: the strong and persistent need to conserve power and extend battery life in portable wireless tags. A POSITA seeking to improve Maloney’s system would have readily looked to such conventional power management solutions.
    • Expectation of Success: As these references all describe common and predictable methods for power saving in wireless devices, a POSITA would have reasonably expected to successfully integrate any of their teachings into Maloney’s RTLS tags to achieve longer operational life.

4. Key Claim Construction Positions

  • Petitioner argued that the term "synchronization signal" should be given its plain and ordinary meaning, encompassing any signal used to establish a timing reference between system components. This construction would prevent the Patent Owner from improperly narrowing the claim scope to exclude prior art like Maloney.
  • Petitioner contended that the phrase "awaiting receipt of the synchronization signal," particularly in the context of independent claims 1 and 15, should be interpreted as describing the implementation of a power-saving protocol where a tag waits in a low-power state. This contrasts with a potential interpretation requiring a novel or complex synchronization mechanism not described in the specification.

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-6, 8-13, and 15-26 of the ’909 patent as unpatentable.