PTAB

IPR2017-02183

Hytera Communications Corp Ltd v. Motorola Solutions Inc

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Method of Efficiently Synchronizing to a Desired Timeslot in a Time Division Multiple Access Communication System
  • Brief Description: The ’991 patent discloses methods for improving synchronization in Time Division Multiple Access (TDMA) communication systems. The invention purports to improve upon the known ETSI Standard for Digital Mobile Radio by using distinct sets of synchronization (SYNC) patterns to identify not only specific timeslots but also the payload type (e.g., voice, data) and the source of a transmission.

3. Grounds for Unpatentability

Ground 1: Obviousness over Yamaguchi, ETSI Standard, and Zak - Claims 7 and 8 are obvious over Yamaguchi in view of the ETSI Standard and Zak.

  • Prior Art Relied Upon: Yamaguchi (Patent 5,761,211), the ETSI Standard (ETSI TS 102 361-1), and Zak (Patent 6,452,991).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Yamaguchi taught a base TDMA system with mutually exclusive SYNC patterns associated with each of its six timeslots, thus disclosing how to differentiate one timeslot from others. The ETSI Standard, which the ’991 patent sought to improve, taught using different SYNC patterns to convey additional information like payload type (voice vs. data) and transmission source (mobile station vs. base station). Finally, Zak was cited for its teaching that a device can switch to an available alternate timeslot if its assigned one is occupied.
    • Motivation to Combine: A POSITA would combine Yamaguchi and the ETSI Standard to add utility to Yamaguchi’s existing SYNC patterns, allowing them to carry payload and source information without sacrificing bandwidth and thereby maximizing channel efficiency. A POSITA would be further motivated to incorporate Zak’s teaching of switching to an available timeslot to reduce transmission delays and improve overall system throughput, which were common goals in communication system design.
    • Expectation of Success: Petitioner asserted a POSITA would have a high expectation of success, as combining these known techniques involved the predictable application of established principles to achieve a more efficient and robust TDMA system.

Ground 2: Obviousness over ETSI Standard and Zak - Claims 7 and 8 are obvious over the ETSI Standard in view of Zak.

  • Prior Art Relied Upon: The ETSI Standard (ETSI TS 102 361-1) and Zak (Patent 6,452,991).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground presented an alternative combination, starting with the ETSI Standard’s two-timeslot TDMA system that already used SYNC patterns to differentiate payload and source. Petitioner argued that Zak taught the benefit of using unique, mutually exclusive SYNC patterns for each individual timeslot to enable direct synchronization.
    • Motivation to Combine: A POSITA would combine the references to enhance the ETSI Standard's system. By implementing Zak's concept of per-timeslot unique SYNC patterns, a device could differentiate and synchronize to a specific timeslot (e.g., timeslot 1 vs. timeslot 2), an improvement over only differentiating payload/source within a general channel. This modification would maximize channel efficiency by enabling more granular control and synchronization, a known design goal.

Ground 3: Obviousness over Yamaguchi, Wiatrowski, and Zak - Claims 7 and 8 are obvious over Yamaguchi in view of Wiatrowski and Zak.

  • Prior Art Relied Upon: Yamaguchi (Patent 5,761,211), Wiatrowski (Application # 2006/0013188), and Zak (Patent 6,452,991).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground was presented as analogous to Ground 1, but it substituted the non-patent ETSI Standard with the Wiatrowski patent publication. Petitioner argued that Wiatrowski taught the same key concept: using SYNC messages to differentiate payload types (voice vs. data/control bursts) and transmission sources (inbound vs. outbound channels). The combination with Yamaguchi's timeslot-specific SYNCs and Zak's timeslot-switching capability followed the same logical progression as in Ground 1.
    • Motivation to Combine: The motivation was identical to that of Ground 1. A POSITA would seek to improve the efficiency and throughput of Yamaguchi's system by adding payload/source information to the SYNC patterns as taught by Wiatrowski and incorporating the flexibility of channel-switching as taught by Zak.
    • Key Aspects: Petitioner explicitly stated this ground was not redundant because it relied exclusively on patent literature, providing an alternative to Grounds 1 and 2, which relied on the non-patent ETSI Standard.
  • Argument for Dependent Claim 8: For all grounds, Petitioner argued that dependent claim 8, which adds that the "desired timeslot" can change over time, recites a routine and expected scenario in any dynamic TDMA system. This is particularly obvious in view of Zak, which taught switching to an alternate timeslot when the desired one is occupied.

4. Key Claim Construction Positions

  • Petitioner argued that several key claim terms should be construed consistently with the positions taken by the parties in a co-pending ITC proceeding. The petition focused on how the prior art met these limitations.
  • "knowing a first set of synchronization patterns... and a second set...": Petitioner contended this was taught by references like Yamaguchi and Zak, which disclosed multiple unique SYNC patterns for multiple timeslots. In such a system, one pattern could be designated as the "first set" for a desired timeslot, and the remaining patterns would constitute the "second set" for other timeslots.
  • "each set [of synchronization patterns] comprising at least two different synchronization patterns as a function of at least one of a payload type and a source of the transmission": This was identified as a key limitation allegedly added during prosecution to overcome prior art. Petitioner argued this feature was not novel, as it was explicitly taught by both the ETSI Standard and Wiatrowski, which used multiple SYNC patterns to differentiate transmissions based on both payload and source.

5. Relief Requested

  • Petitioner requested the institution of an inter partes review and the cancellation of claims 7 and 8 of Patent 8,279,991 as unpatentable under 35 U.S.C. §103.