PTAB

IPR2024-00730

AT&T Corp v. Daingean Technologies Ltd

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1. Case Identification

2. Patent Overview

  • Title: Base Station Apparatus, Terminal Apparatus, Communication Method, and Integrated Circuit
  • Brief Description: The ’509 patent is directed to wireless communication systems, such as 4G and 5G networks. The technology involves methods for efficiently performing uplink and downlink communication by segmenting a transport block into multiple code blocks (CBs) of different sizes, which are then grouped into different sized code block groups (CBGs) for HARQ-ACK feedback.

3. Grounds for Unpatentability

Ground 1: Claims 4, 5, 10, and 11 are anticipated and rendered obvious by Lee

  • Prior Art Relied Upon: Lee (Application # 2019/0327024).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Lee anticipates or renders obvious all challenged claims. Lee discloses a radio access network (RAN) node (a base station) that segments encoded information into multiple code blocks and groups them into code block groups aligned with OFDM symbol boundaries for efficient processing and HARQ-ACK feedback. Petitioner contended Lee expressly teaches segmenting a transport block into CBs of different sizes, satisfying the limitations requiring "first CBs" of a "first size" and "second CBs" of a "second size." For example, Lee’s Figure 4 shows CBs with 12 resource elements and others with 6. Lee also discloses grouping these CBs into CBGs containing different numbers of CBs, thereby meeting the limitations related to "first CBGs" (containing more CBs) and "second CBGs" (containing fewer CBs). Petitioner asserted that the example in Lee's Paragraph 39, which describes CBG0 with two CBs, CBG1 with five CBs, and CBG2 with seven CBs, directly maps to the claim limitations regarding CBG composition and size hierarchy. Specifically, Petitioner argued this example teaches a "first CBG" (e.g., CBG2) that includes the "greatest number" of "second CBs" (smaller CBs), satisfying the final limitation of claims 4 and 10. The arguments for claims 5 and 11 rely on similar mappings, using an example from Lee’s Paragraph 42 describing CBs of 960 and 1000 resource elements to show different CB sizes and CBGs with different compositions.
    • Motivation to Combine (for §103 grounds): The petition asserted that, to the extent any limitation is not explicitly disclosed, it would have been obvious to a person of ordinary skill in the art (POSITA). For instance, Petitioner argued a POSITA would be motivated to apply the general teachings of Lee's Paragraph 39 (describing various CBG compositions) to the specific embodiment of Lee's Figure 4. This would involve modifying the segmentation to create more, smaller CBs to evenly allocate the risk of error and provide more redundancy, reducing the need for retransmissions.
    • Expectation of Success: Petitioner contended a POSITA would have a high expectation of success because Lee's teachings concern predictable electrical engineering principles and established wireless communication protocols. The proposed modifications were based on express teachings within Lee for improving performance.

Ground 2: Claims 4, 5, 10, and 11 are anticipated and rendered obvious by Zheng

  • Prior Art Relied Upon: Zheng (Application # 2019/0173499).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Zheng also anticipates or renders obvious all challenged claims. Zheng discloses a communication device (e.g., a base station) that segments a transport block into multiple CBs of different sizes and groups them into CBGs to improve transmission reliability and efficiency, including performing ACK feedback by CBG. Petitioner relied heavily on Zheng's Table 1, which provides a detailed example of code block segmentation. To meet the claim limitations requiring CBs of different sizes, Petitioner showed that Table 1 discloses CBs with different input bit segment lengths (e.g., 6140 bits vs. 6139 bits). These CBs are organized into four distinct CBGs. Petitioner argued this example explicitly satisfies limitations [4f]-[4h] by showing CBGs with different total numbers of CBs. For instance, CBG3 contains three CBs of a smaller size ("second CBs"), while CBG0 contains only two CBs of a larger size ("first CBs"), establishing CBG3 as a "first CBG" and CBG0 as a "second CBG." The analysis demonstrated that this "first CBG" (CBG3) contains the greatest number of "second CBs" (three), satisfying limitation [4i]. For claims 5 and 11, Petitioner mapped the "size" limitation to the "length (bits) of a filler bit segment" in Zheng's Table 1 (5 bits vs. 4 bits), again showing how the table's explicit values satisfy the claim requirements for CB and CBG size and composition hierarchies.
    • Motivation to Combine (for §103 grounds): The obviousness argument for Zheng is presented as an alternative. Petitioner asserted that Zheng's disclosure provides a clear blueprint for segmenting transport blocks to reduce the need for filler bits and improve efficiency. A POSITA would have understood that the specific numerical examples in Zheng could be adapted to different scenarios, and that the principles taught were broadly applicable, making any minor variation to arrive at the claimed invention obvious.
    • Expectation of Success: Success was expected because Zheng's methods operate on well-understood principles of data transmission and error checking. The detailed tables and figures provide a clear and predictable implementation path.

4. Arguments Regarding Discretionary Denial

  • Petitioner argued that discretionary denial under §325(d) is inapplicable. The petition asserted that the prior art references, Lee and Zheng, were never filed in an Information Disclosure Statement (IDS) during the prosecution of the ’509 patent. Therefore, the Examiner never identified, considered, or used these references to reject the claims, and the grounds raised in the petition are not substantially the same as arguments previously considered by the USPTO.

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 4, 5, 10, and 11 of the ’509 patent as unpatentable.