PTAB

IPR2024-01143

AT&T Enterprises LLC v. Innovative Sonic Ltd

Log In
Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Error handling in a wireless communications system
  • Brief Description: The ’059 patent discloses a method for detecting an erroneous sequence number in a status report within a wireless communication system operating in Acknowledged Mode (AM). The invention specifically addresses a flaw in the 3GPP standard's error checking inequality, which fails to detect errors in the edge case where two state variables, VT(A) and VT(S), are equal, by proposing a modified inequality using a "less than" operator instead of a "less than or equal to" operator.

3. Grounds for Unpatentability

Ground 1: Claims 1-3 and 5-8 are anticipated by 3GPP-4.60-v860-Specification

  • Prior Art Relied Upon: 3GPP-4.60-v860 (3GPP TS 04.60 V8.6.0 (2000-10)).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that 3GPP-4.60-v860, a technical specification for the GSM EDGE Radio Access Network, discloses every element of the challenged claims. It teaches a method for detecting erroneous sequence numbers in a Radio Link Control (RLC) acknowledged mode by using the inequality [ V(A) ≤ BSN < V(S) ] modulo SNS. Petitioner asserted this expression is analogous to the claimed method, where V(A) is the sequence number following the last in-sequence acknowledged packet, V(S) is the sequence number of the next packet to be transmitted, and BSN is the negatively acknowledged sequence number being checked. An erroneous sequence number is detected if it falls outside this defined range, thus anticipating the core invention of the ’059 patent.

Ground 2: Claims 1-3 and 5-8 are obvious over 3GPP-4.60-v860-Specification

  • Prior Art Relied Upon: 3GPP-4.60-v860 (3GPP TS 04.60 V8.6.0 (2000-10)).
  • Core Argument for this Ground:
    • Prior Art Mapping: As an alternative to anticipation, Petitioner argued that 3GPP-4.60-v860 renders the claims obvious. The reference discloses all key elements, including the specific inequality for detecting erroneous sequence numbers.
    • Motivation to Combine (for §103 grounds): To the extent any minor element, such as the exact format of a "status report unit," is not explicitly disclosed, a person of ordinary skill in the art (POSITA) would have found it obvious to apply the error detection method of 3GPP-4.60-v860 within a standard wireless communication framework. Implementing a known error-checking algorithm to ensure reliable data transmission was a predictable and routine design choice.

Ground 3: Claims 1-8 are obvious over 3GPP-25.322-v630-Specification in view of 3GPP-4.60-v860-Specification

  • Prior Art Relied Upon: 3GPP-25.322-v630 (3GPP TS 25.322 V6.3.0 (2005-03)) and 3GPP-4.60-v860 (3GPP TS 04.60 V8.6.0 (2000-10)).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner contended that 3GPP-25.322-v630, a 3G UMTS RLC protocol specification, teaches nearly all claimed elements. It discloses using the inequality VT(A) ≤ ‘Sequence Number’ ≤ VT(S)-1 for error checking, which is the exact expression the ’059 patent identifies as flawed when VT(A) equals VT(S). The secondary reference, 3GPP-4.60-v860, supplies the solution by teaching the inequality [ V(A) ≤ BSN < V(S) ], which correctly handles the edge case.
    • Motivation to Combine (for §103 grounds): A POSITA, aware of the protocol error in the 3GPP-25.322-v630 standard when VT(A)=VT(S), would have been motivated to find a solution. The POSITA would combine the teachings of 3GPP-4.60-v860, an earlier but analogous RLC protocol standard, by replacing the flawed "less than or equal to" inequality with the robust "less than" inequality to fix the known bug and improve system reliability. Additional motivation was cited to reduce computational overhead by removing the "-1" operation.
    • Expectation of Success: A POSITA would have had a high expectation of success because both references are 3GPP standards governing the same RLC layer functions and use analogous state variables. Substituting one inequality expression for another to solve a known, narrow problem would have been a predictable and straightforward modification.

4. Arguments Regarding Discretionary Denial

  • §325(d) Arguments: Petitioner argued against discretionary denial under §325(d), asserting that 3GPP-4.60-v860 is new prior art that was not before the Examiner during prosecution. While 3GPP-25.322-v630 was listed in an IDS, it was never applied in a rejection. Petitioner contended the combination of these references presents arguments and art in a new light, addressing the specific reason for allowance.
  • §314(a) Fintiv Arguments: Petitioner argued that the Fintiv factors weigh against discretionary denial based on parallel district court litigation. Key arguments included that the district court case is in its early stages with minimal investment (Factor 3), and that Petitioner stipulates not to pursue the same invalidity grounds in district court if the IPR is instituted, eliminating overlap concerns (Factor 4). Petitioner also asserted that the compelling merits of the petition, which presents art the Examiner was likely unaware of, weigh strongly in favor of institution (Factor 6).

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-8 of the ’059 patent as unpatentable.