PTAB

IPR2020-01102

Cradlepoint Inc v. Sisvel Intl SA

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Radio Link Control Unacknowledged Mode Header
  • Brief Description: The ’443 patent relates to telecommunications protocols, specifically the radio link control (RLC) layer in 3G cellular systems like UMTS. The invention purports to optimize data transmission by redefining the meaning of certain special-purpose length indicators (LIs) within a protocol data unit (PDU) to signal when the PDU is perfectly filled with one or more complete service data units (SDUs), thereby avoiding the need for separate padding indicators.

3. Grounds for Unpatentability

Ground 1: Anticipation by Lee - Claims 1, 2, 4-5, 7, 10, 16-17, 19-20, 22, 25, and 30-31 are anticipated by Lee under 35 U.S.C. §102.

  • Prior Art Relied Upon: Lee (Korean Registered Patent 10-0404188).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Lee discloses every element of the challenged claims. Lee addresses the identical problem of handling PDUs that have insufficient space for both a padding indicator and the padding itself. Lee teaches a method of generating an RLC PDU by inserting one or more SDUs and using a "new LI" with a special, predefined value. This new LI is used when the SDUs precisely fill the remaining space in the PDU. Petitioner asserted this special LI inherently indicates that a first data octet of the PDU is the first octet of a first SDU and that the last octet of the PDU is the last octet of another (or the same) SDU, thus comprising one or more completed SDUs. Lee’s disclosure of using a transmitting apparatus (e.g., a UE or UTRAN) to generate these PDUs was argued to meet the apparatus limitations.

Ground 2: Obviousness over TS25.322 and Lee - Claims 1-14, 15-28, and 30-31 are obvious over TS25.322 in view of Lee under 35 U.S.C. §103.

  • Prior Art Relied Upon: TS25.322 (3GPP TS 25.322 v6.1.0 (2004-06)) and Lee (Korean Registered Patent 10-0404188).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner contended that TS25.322, as the foundational 3GPP standard for the RLC protocol, discloses the basic framework of the claims, including inserting SDUs into PDUs and using special LIs for various signaling purposes (e.g., LI '1111100' indicates the PDU starts with the first octet of an SDU). Lee teaches a specific solution to a known efficiency problem within this exact framework: using a special LI to indicate a PDU is precisely filled with complete SDUs. The combination, therefore, teaches providing a single LI that both indicates the start of an SDU (from TS25.322) and that the PDU contains one or more complete SDUs ending at the PDU boundary (from Lee).
    • Motivation to Combine: A person of ordinary skill in the art (POSITA) would have been motivated to combine the teachings to improve efficiency. Knowing from TS25.322 that special LIs were used for signaling, and facing the precise-fit scenario described in Lee, a POSITA would combine the concepts by modifying an existing special LI from TS25.322 to also carry the meaning taught by Lee. This would efficiently use PDU capacity, reduce overhead, and improve bandwidth, which are all well-known goals in telecommunications protocol design.
    • Expectation of Success: A POSITA would have had a reasonable expectation of success because Lee’s method is a direct and predictable optimization for the RLC protocol described in TS25.322. Applying Lee's signaling logic to the established LI structure of TS25.322 was presented as a straightforward implementation.

Ground 3: Obviousness over Qualcomm and TS25.322 - Claims 1-31 are obvious over Qualcomm in view of TS25.322 under §103.

  • Prior Art Relied Upon: Qualcomm (R2-050969 L2 Optimizations for VoIP) and TS25.322 (3GPP TS 25.322 v6.1.0).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner argued this combination teaches all challenged claims. Qualcomm explicitly addresses a shortcoming in the TS25.322 standard: if a PDU is lost, it is impossible to know if the first SDU in the next PDU is complete. Qualcomm proposes "to signal in-band whether the first SDU is entirely included in the current PDU" by either using a reserved LI value or, more relevantly, modifying the existing LI structure to add a one-bit flag. Petitioner asserted this modified LI—with one bit as a flag for the start of the SDU and the remaining bits indicating the end of that SDU—discloses the key limitation of providing a single indicator for both the start of a first SDU and the end of an SDU.
    • Motivation to Combine: The motivation was explicit. Qualcomm directly proposed its solution as an enhancement to the TS25.322 standard to solve a recognized problem. A POSITA seeking to improve the robustness and efficiency of the RLC protocol defined in TS25.322 would have been directly motivated by Qualcomm's disclosure to implement the proposed signaling change.
    • Expectation of Success: Success would have been expected because Qualcomm provides a concrete, engineered solution designed specifically for the TS25.322 protocol. It details how the LI structure could be modified, making implementation a matter of routine design choice.

  • Additional Grounds: Petitioner asserted an alternative ground that claims 1, 2, 4-8, 10-12, 16-17, 19-23, 25-26, 28, and 30-31 are obvious over Lee alone, arguing that even if Lee did not explicitly disclose every limitation, any minor gaps would have been obvious to a POSITA.

4. Key Claim Construction Positions

  • "Inserting Unit" / "Inserting Means" (claims 16, 30) and "Providing Unit" / "Providing Means" (claims 16, 30): Petitioner argued these are means-plus-function terms under pre-AIA §112, ¶6.
    • The function for "inserting unit/means" was identified as "insert[ing]…at least one service data unit to a protocol data unit of an appropriate size."
    • The function for "providing unit/means" was identified as "provid[ing]… at least one indicator including a [LI] configured to indicate that a first data octet of the [PDU] is a first octet of a first [SDU] and at least one other octet of the [PDU] is the last octet of another [SDU]."
    • The corresponding structure for both was identified in the ’443 patent as a component of a mobile station or network element (UTRAN), such as hardware or a processor executing code, that performs the RLC protocol functions as described in the specification and associated algorithms. Petitioner argued the prior art disclosed identical or equivalent structures.

5. Relief Requested

  • Petitioner requests the institution of an inter partes review and the cancellation of claims 1-31 of Patent 7,894,443 as unpatentable.