Sercomm Corp v. Atlas Global Technologies LLC

1. Case Identification

• Case #: IPR2022-01519
• Patent #: 9,912,513
• Filed: September 9, 2022
• Petitioner(s): Sercomm Corp.
• Patent Owner(s): Atlas Global Technologies, LLC
• Challenged Claims: 1-19

2. Patent Overview

• Title: System and Method for Synchronization for OFDMA Transmission
• Brief Description: The ’513 patent discloses systems for synchronizing uplink wireless communications from multiple stations (STAs) to a central access point (AP). The AP transmits a "trigger frame" that allocates resources and indicates a specific guard interval (GI) or cyclic prefix (CP) for the STAs to use in their subsequent multi-user (MU) uplink transmissions, improving the AP's ability to decode the incoming signals.

3. Grounds for Unpatentability

Ground 1: Obviousness over Chun in view of Lou - Claims 1-19 are obvious over Chun in view of Lou.

• Prior Art Relied Upon: Chun (Patent 10,034,288) and Lou (Application # 2013/0286959).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Chun, the primary reference, taught all key limitations of the independent claims. Chun disclosed an AP transmitting an "uplink transmission indication frame" to multiple STAs to trigger and coordinate a subsequent uplink multi-user (UL MU) transmission. Petitioner asserted a person of ordinary skill in the art (POSA) would understand this indication frame to be the claimed "trigger frame." Chun's frame was shown to allocate resources and include information to vary the guard interval for the responsive uplink physical layer protocol data units (PPDUs). For claim 14, which required the GI indication to be in the payload of the downlink frame, Petitioner relied on Lou. Lou explicitly taught including a "Short GI" field within the payload (STA Info fields) of a downlink announcement frame to indicate the GI for the subsequent uplink.
  • Motivation to Combine: Petitioner contended a POSA would combine Chun and Lou to improve wireless communication within the 802.11 standard, as both references operate in this domain and utilize PPDUs. While Chun taught sending GI information, it did not specify its exact location within the frame. Lou provided a clear and logical location for this information—the payload. A POSA would be motivated to place the GI indication in the payload, as taught by Lou, because the payload affords more space and flexibility than fixed-size header fields, representing a predictable design choice.
  • Expectation of Success: A POSA would have had a high expectation of success in modifying Chun's system to place the GI indication in the payload, as it involved combining known elements for their intended purpose to yield a predictable result.

Ground 2: Obviousness over Rong in view of Chun - Claims 1-19 are obvious over Rong in view of Chun.

• Prior Art Relied Upon: Rong (Patent 10,135,652) and Chun (Patent 10,034,288).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Rong, as the primary reference, taught the core concept of the invention. Rong disclosed an AP transmitting "uplink scheduling information" (the claimed "trigger frame") to multiple STAs, which included an indicator for the cyclic prefix (CP) length to be used in the responsive UL MU transmission. Petitioner asserted that a POSA would understand the disclosed CP to be equivalent to the claimed guard interval. For dependent claims requiring more specific frame structures (e.g., claims 5-8, 16-17), Petitioner relied on Chun. Rong's disclosure was simplified, depicting transmissions as single OFDM symbols. Chun was used to supply a more realistic and detailed PPDU frame structure, including a legacy header (L-part) and a non-legacy/high-efficiency header (HE-part), and explicitly taught using different CP/GI lengths for these different parts of the frame.
  • Motivation to Combine: Petitioner argued a POSA would be motivated to improve Rong's simplified system with Chun's more detailed and efficient frame structure. A POSA would recognize that real-world wireless transmissions involve multiple OFDM symbols, not one, and would look to prior art like Chun for established, standard frame formats. Furthermore, a POSA would know that using a single, fixed GI for an entire frame (as implied by Rong) is inefficient. Applying Chun's teaching of flexible, variable GIs for different parts of a frame (e.g., a shorter GI for the legacy portion and a different GI for the high-efficiency portion) would create a more efficient frame that does not waste space on unnecessarily long timing buffers, a known problem in the art.
  • Expectation of Success: A POSA would have reasonably expected success in applying Chun's more realistic, standard-compliant frame structures and variable GI techniques to Rong's foundational system. This combination represented the application of known, compatible techniques to improve efficiency and was a predictable implementation choice.

4. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial under Fintiv would be inappropriate due to the strong merits of the petition, which was based on prior art not previously considered by the USPTO.
• Petitioner further stipulated that it would not assert in the parallel district court litigation the same grounds, or any grounds that could have reasonably been raised in the petition, thereby neutralizing the Fintiv concerns as guided by the Director's memorandum.
• Petitioner also contended that denial under §325(d) would be inappropriate because the asserted prior art (Chun and Rong) was substantively different from the art considered during prosecution.

5. Relief Requested

• Petitioner requests institution of inter partes review (IPR) and cancellation of claims 1-19 of the ’513 patent as unpatentable.