PTAB

IPR2013-00601

Broadcom Corp v. Telefonaktiebolaget L M Ericsson

Log In
Key Events
Petition
petition Intelligence

1. Case Identification

2. Patent Overview

  • Title: Method for Minimizing Feedback Responses in ARQ Protocols
  • Brief Description: The ’215 patent discloses a method for data communication systems using an Automatic Repeat Request (ARQ) protocol. The alleged invention allows a receiving device to select from multiple types of feedback responses (e.g., a list of missing data units or a bitmap representation) to report transmission errors, and to use a "type identifier field" within a feedback message to inform the transmitting device which response type is being used, thereby optimizing transmission efficiency.

3. Grounds for Unpatentability

The petition presented two independent grounds, arguing that all challenged claims are anticipated under 35 U.S.C. § 102 by two separate prior art references.

Ground 1: Anticipation Over Seo - Claims 1, 2, 4, 6, 8, 15, 22, 25, 26, 29, 32, 34, 45, 46, 49, 52, and 54 are anticipated by Seo.

  • Prior Art Relied Upon: Seo (Patent 6,581,176).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Seo discloses every element of the challenged claims. Seo teaches an ARQ protocol in a wireless system that uses two distinct types of negative acknowledgement (NAK) feedback. The first type, a "First/Last Approach," identifies a consecutive range of missing frames using start and end sequence numbers. The second, a "Bitmap Approach," uses a bitmap to identify non-consecutive missing frames. Petitioner asserted that Seo’s "NAK_TYPE" field, which indicates which of the two feedback approaches is being used, directly corresponds to the "type identifier field" limitation central to the ’215 patent claims.
    • Petitioner further mapped Seo’s disclosure to the independent claims. For method claim 1, Seo’s system sends and receives data units, and the receiver constructs a feedback response containing the NAK_TYPE field (type identifier), sequence number fields (e.g., FIRST, LAST), and a content field (the NAK_Map bitmap). This mapping was extended to system claim 45, which recites a similar system with means-plus-function limitations corresponding to Seo’s transmitter and receiver. The arguments for method claims 15 and 25, which recite variations of message fields, were also based on Seo’s disclosure of sequence numbers, bitmaps, and length fields within its selectable NAK frames. The dependent claims were shown to be anticipated by Seo's explicit disclosure of bitmap messages and feedback containing information about erroneous data units.

Ground 2: Anticipation Over Gong - Claims 1, 2, 4, 6, 8, 15, 22, 25, 26, 29, 32, 34, 45, 46, 49, 52, and 54 are anticipated by Gong.

  • Prior Art Relied Upon: Gong ("An Application-Oriented Error Control Scheme for High-Speed Networks," IEEE/ACM Transactions on Networking, 1996).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner contended that Gong, an article describing an error control scheme for high-speed networks, discloses an ARQ protocol with multiple feedback types identified by a type field. Gong describes two types of acknowledgement packets: a positive acknowledgement (PACK) and a selective negative acknowledgement (SNAK). A dedicated "type" field in the packet header identifies the packet type, with type=3 indicating a PACK and type=4 indicating a SNAK. Petitioner argued this directly reads on the "type identifier field" limitation.
    • The format of the feedback packet in Gong changes based on the value of the "type" field; specifically, the SNAK packet contains a "retransmission bitmap" to identify erroneous packets, which is absent from the PACK packet. Petitioner argued this bitmap meets the claim limitations requiring a bitmap message or a content field comprising a bitmap. Gong's packets also contain various sequence number fields (e.g., "ACK segment no."), which were mapped to corresponding claim limitations. As with the Seo ground, Petitioner applied this mapping to all independent method claims (1, 15, 25) and the independent system claim (45), arguing that Gong’s disclosure of a transmitter and receiver that generate these distinct, type-identified packets anticipates the claimed inventions in their entirety.

4. Key Claim Construction Positions

  • Petitioner argued, consistent with a prior district court ruling involving the ’215 patent, that the preambles of the claims (e.g., "A method for minimizing feedback responses...") are not substantive limitations. This position simplifies the anticipation analysis by focusing the inquiry on the specific steps and structures recited in the body of the claims, rather than a broader purpose of "minimizing" feedback.
  • For means-plus-function claims (e.g., claim 45), Petitioner identified the corresponding structure in the ’215 patent's specification as the general "ARQ entity," which includes a processor. Petitioner argued that the level of structural detail disclosed in the prior art references (Seo and Gong) for their respective transmitting and receiving entities was substantially identical to that of the ’215 patent, making them sufficient for an anticipation analysis.

5. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 1, 2, 4, 6, 8, 15, 22, 25, 26, 29, 32, 34, 45, 46, 49, 52, and 54 of the ’215 patent as unpatentable.