PTAB

IPR2018-00128

Hytera Communications Co Ltd v. Motorola Solution Inc

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Method, Device and System for Temporarily Selecting a Timeslot
  • Brief Description: The ’284 patent discloses a method for a radio communication device in a Time Division Multiple Access (TDMA) network to manage channel selection. The device has an assigned default timeslot, determines if it is available for communication with a talkgroup, and if not, temporarily searches for and selects an alternate available timeslot, re-selecting the default timeslot when it becomes available again.

3. Grounds for Unpatentability

Ground 1: Claims 1, 4-9, 12-15, and 18-19 are obvious over Barnes in view of Janky.

  • Prior Art Relied Upon: Barnes (Patent 6,374,115) and Janky (Patent 5,790,527).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Barnes taught the core inventive concept of the ’284 patent in the context of Frequency Division Multiple Access (FDMA) channels. Barnes disclosed a trunked radio system where a subscriber unit has an assigned "home channel" (equivalent to the claimed "default timeslot"). If the home channel is unavailable, the unit determines this and switches to an alternate "free channel," "alias channel," or "backup channel" from a list. Petitioner asserted that Janky taught a method for adding TDMA capabilities to an existing FDMA system to increase the number of available channels, effectively converting frequency channels into timeslots.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine Janky’s teachings with the system of Barnes to achieve the well-known goal of increased spectral efficiency and capacity. Petitioner noted that Barnes broadly stated its methods could be performed by "any protocol," and combining FDMA and TDMA was a common practice in the art. Janky provided a strong motivation by explaining how to add TDMA to increase channel availability.
    • Expectation of Success: A POSITA would have a high expectation of success because Janky provided an "instruction manual" for implementing TDMA in an FDMA system, making the combination of the references' teachings straightforward and predictable.

Ground 2: Claims 1, 4-9, 12-15, and 18-19 are anticipated by Ganucheau.

  • Prior Art Relied Upon: Ganucheau (Patent 6,529,740).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted Ganucheau disclosed all limitations of the challenged claims. Ganucheau taught a group radio system where subscriber radios autonomously select communication channels from a downloaded channel list based on their current time and location, rather than relying on a central controller. This was argued to anticipate the subscriber-led selection process of the ’284 patent. Ganucheau explicitly disclosed that its channels could be implemented using TDMA, FDMA, or CDMA techniques, thus teaching timeslots. The subscriber radio determines if its current channel has acceptable signal quality or will soon become inactive. If it is deemed unavailable, the radio searches the list for a "best candidate multipoint channel" and temporarily switches to it, anticipating the claimed steps of determining availability, searching, and temporarily selecting.

Ground 3: Claims 1, 4-9, 12-15, and 18-19 are anticipated by Wiatrowski.

  • Prior Art Relied Upon: Wiatrowski (Patent 8,279,991), which incorporates by reference U.S. Patent Application Ser. No. 12/331,180 (the ’180 application).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Wiatrowski, through its incorporation of the ’180 application, disclosed a TDMA communication system that anticipated the claims. The system assigned a default "rest timeslot" to subscriber units. If a unit determined the rest timeslot was busy (by detecting synchronization patterns), it would search for and select a different "undesirable" timeslot for communication. Wiatrowski further disclosed embodiments with only two timeslots; in this scenario, if the default timeslot is busy, the radio selects the only other available channel, which Petitioner contended anticipated dependent claims 4, 12, and 18. The system also re-selects the "desired" rest channel once it becomes available, mapping to the final step of the challenged independent claims.

4. Key Claim Construction Positions

  • "default timeslot": Petitioner argued this term should be construed broadly to include a timeslot that can change based on time, location, or other criteria, not merely a single, permanently fixed assignment. This position was supported by the specification and the Patent Owner's own arguments in a parallel International Trade Commission (ITC) proceeding.
  • "when the default timeslot becomes available" / "when the default timeslot is unavailable": Petitioner contended these temporal phrases should not be limited to actions occurring immediately upon the condition being met. Instead, they should be construed to include actions that occur at some later point in time, a construction also allegedly advanced by the Patent Owner in the parallel ITC case.
  • "common announcement channel": Petitioner argued this term should not be limited to a TDMA channel. Based on the art and the specification, it should encompass any type of channel, including an FDMA channel, used to send announcement information from a repeater to radio devices.

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1, 4-9, 12-15, and 18-19 of Patent 8,116,284 as unpatentable.