PTAB

IPR2025-01188

Samsung Electronics Co Ltd v. Hannibal IP LLC

Log In
Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Method and Apparatus for LBT Failure Detection
  • Brief Description: The ’535 patent discloses a procedure for a user equipment (UE) to detect a Listen-Before-Talk (LBT) failure and initiate recovery. The claimed method involves increasing an LBT failure counter upon receiving a failure indication and determining that an LBT failure event has occurred when the counter meets or exceeds a threshold, which then triggers a recovery procedure.

3. Grounds for Unpatentability

Ground 1: Obviousness over Shi and TS-38.321 - Claims 1, 3-4, 7-8, 10, 12-13, 16-17, and 19-20 are obvious over Shi in view of TS-38.321.

  • Prior Art Relied Upon: Shi (International Publication No. WO 2020/087369) and TS-38.321 (3GPP Technical Specification 38.321 v15.3.0).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Shi, a patent application filed before the ’535 patent’s priority date, discloses all elements of independent claims 1 and 10 except for resetting the LBT failure counter upon a MAC entity reset request from an upper layer. Specifically, Petitioner asserted that Shi teaches a UE receiving an LBT failure indication at its Medium Access Control (MAC) layer from a lower physical (PHY) layer, increasing a "global counter" for such failures, and determining a failure event has occurred when the counter reaches a threshold, thereby triggering a recovery procedure. For the final element, Petitioner contended Shi discloses that the upper Radio Resource Control (RRC) layer can trigger a recovery procedure that includes resetting the MAC entity.
    • Motivation to Combine: A POSITA would combine Shi with TS-38.321 because TS-38.321 is a foundational 5G/NR MAC protocol specification that provides the conventional implementation details for procedures generally described in Shi. Petitioner argued that when Shi teaches resetting a MAC entity, a POSITA would look to the standard procedure in TS-38.321, which explicitly states that upon a MAC reset request from upper layers, the MAC entity shall reset associated counters (e.g., "BFI_COUNTER"). The primary motivation was to restore the MAC entity to a default state to resolve the failure, which logically includes resetting related counters to prevent premature failure detection on subsequent attempts.
    • Expectation of Success: Petitioner asserted a high expectation of success because implementing the teachings of TS-38.321 was a straightforward, conventional step to complete the MAC reset procedure in Shi. The combination involved applying a standard protocol detail to a system operating under that protocol.

Ground 2: Obviousness over Shi, Hong, and TS-38.321 - Claims 1-8, 10-17, and 19-20 are obvious over Shi in view of Hong and TS-38.321.

  • Prior Art Relied Upon: Shi (WO 2020/087369), Hong (International Publication No. WO 2020/045920), and TS-38.321.

  • Core Argument for this Ground:

    • Prior Art Mapping: This ground presented an alternative or supplemental argument for the independent claims and also targeted additional dependent claims. Petitioner asserted that, like Shi, Hong discloses managing an LBT failure counter and initiating an RRC connection re-establishment procedure upon failure, which includes "reset[ting] the MAC." This teaching from Hong strengthened the argument that resetting the MAC entity (and its associated counters) was a known element of the recovery procedure. For dependent claim 2, which adds switching an active Bandwidth Part (BWP) after an LBT failure, Petitioner argued that Shi’s teaching of "reconfiguring the uplink BWP" combined with Hong’s explicit disclosure of changing the BWP in response to a detected LBT failure rendered the claim obvious.
    • Motivation to Combine: A POSITA would combine Shi with Hong because both references address the same LBT failure problem in 5G/NR systems and propose similar solutions. Hong provided additional, explicit details on standard recovery procedures like BWP switching that a POSITA would have naturally considered to improve the system in Shi. The motivation for adding Hong’s BWP switching was to enhance communication reliability by moving from a congested BWP to one with a higher probability of LBT success.
    • Expectation of Success: Petitioner argued for a high expectation of success, as the combination involved integrating well-known recovery techniques into a system already designed for such functionalities. Both Shi and Hong describe similar network components, and Shi’s UE was already capable of reconfiguring BWPs, making the modification straightforward and predictable.

  • Additional Grounds: Petitioner asserted additional obviousness challenges, including combining Shi, TS-38.321, and Terry (WO 2020/069114) for claims 2-3 and 11-12, and combining Shi, Hong, TS-38.321, and Alfarhan (WO 2019/245779) for claims 9 and 18, relying on similar motivations to combine known LBT failure recovery techniques.

4. Relief Requested

  • Petitioner requests institution of inter partes review and cancellation of claims 1-20 of the ’535 patent as unpatentable.