PTAB

IPR2024-00392

Ericsson Inc v. General Access Solutions Ltd

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Petition
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1. Case Identification

2. Patent Overview

  • Title: Wireless Communication Using Time Division Duplex and Beam Forming
  • Brief Description: The ’931 relates to a wireless access network system using Time Division Duplex (TDD) communication. The system involves a base station that transmits a broadcast beam signal to multiple sectors at the start of a TDD frame, followed by directed, scanning data beams to specific wireless devices within one or more sectors during the downlink portion of that same frame.

3. Grounds for Unpatentability

Ground 1: Claims 28-29 are obvious over Vornefeld in view of Atsuta.

  • Prior Art Relied Upon: Vornefeld (an IEEE Communication Magazine article, Nov. 1999) and Atsuta (Patent 6,160,800).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that the Patent Owner previously conceded in a prior inter partes review (IPR) that Vornefeld anticipates all limitations of the independent claims (1 and 19) from which the challenged claims depend. This includes a TDD system using beamforming to send a broadcast signal across a cell site, followed by a first directed data transmission to one sector within a single TDD frame. The novel feature of challenged claims 28-29 is the transmission of a second downlink data packet to a device in another sector within the same TDD frame. Petitioner argued that Atsuta, which was not previously considered, explicitly teaches this feature. Atsuta describes a TDMA system where data for subscribers in different sectors (zones) is transmitted within a single, common synchronous frame to simplify hardware and reduce power consumption.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine Vornefeld's TDD/SDMA system with Atsuta's single-frame, multi-sector transmission method. Vornefeld acknowledges computational complexity as a concern, and Atsuta's method directly addresses this by simplifying the signal processing structure. This combination represented a predictable design choice to improve efficiency in Vornefeld's known system.
    • Expectation of Success: A POSITA would have a reasonable expectation of success in the combination because both references describe compatible frame-based communication systems using directional antennas. Integrating Atsuta's method of allocating time slots for different sectors into a single frame within Vornefeld's existing frame structure would be a straightforward and predictable variation.

Ground 2: Claims 28-29 are obvious over Vornefeld in view of Goldburg.

  • Prior Art Relied Upon: Vornefeld (an IEEE Communication Magazine article, Nov. 1999) and Goldburg (Patent 6,154,661).
  • Core Argument for this Ground:
    • Prior Art Mapping: Similar to Atsuta, Goldburg teaches transmitting data to subscribers in different "regions" (subdivisions of a cell site) within a single TDD frame. Goldburg discloses an enhanced beamforming technique where weight vectors are calculated for each region to create targeted, narrow beams, thereby reducing interference between subscribers. This supplies the teaching of transmitting to a second subscriber in a second location within the same frame that was missing from the analysis of Vornefeld alone in the prior IPR.
    • Motivation to Combine: A POSITA would be motivated to combine Goldburg's region-based beamforming technique with Vornefeld’s system to improve transmission efficiency and minimize interference, a problem central to both references. Vornefeld provides the general framework for using weight vectors, and Goldburg provides a specific, advanced implementation for targeting individual users in different regions within a single frame.
    • Expectation of Success: Success would be predictable because Vornefeld’s system is already designed to transmit to multiple subscribers and can move its transmission beam for each time slot. Incorporating Goldburg’s method for defining regions and using weight vectors to aim beams at those different regions would be a logical extension of Vornefeld’s existing capabilities.

Ground 3: Claims 28-29 are obvious over Youssefmir in view of Atsuta.

  • Prior Art Relied Upon: Youssefmir (Patent 6,795,409) and Atsuta (Patent 6,160,800).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner presented Youssefmir as a new primary reference that teaches a TDD/SDMA wireless system using a smart antenna to transmit to multiple users in different downlink time slots within a single frame. While Youssefmir recognizes cell sectorization, it does not explicitly state that users in different time slots of the same frame are in different sectors. Petitioner argued Atsuta supplies this teaching by describing a frame structure where different time slots are explicitly allocated to subscribers across different sectors.
    • Motivation to Combine: A POSITA would be motivated to apply Atsuta's known single-frame, multi-sector technique to Youssefmir’s compatible single-frame system. Youssefmir notes that insufficient processing capability is a concern, and Atsuta’s method simplifies the required hardware and alleviates computational limitations. This makes the combination an obvious design choice to improve Youssefmir’s system.
    • Expectation of Success: The combination would yield predictable results. Youssefmir's frame structure is already designed for multi-user transmission, and Atsuta provides a known, compatible option for arranging those users across different sectors within that single frame.

  • Additional Grounds: Petitioner asserted additional obviousness challenges over Vornefeld and Atsuta in further view of Tangemann, and over Vornefeld and Goldburg in further view of Tangemann, arguing Tangemann provides further teachings on subdividing a cell site into "minisectors" to improve beamforming precision.

4. Key Claim Construction Positions

  • Petitioner argued that the challenged claims are obvious under any reasonable construction of the term "sector." This includes the Patent Owner's broad construction advanced in related litigation ("a portion of the cell site") as well as a narrower, more traditional construction ("a section of the cell site defined by the transmission area of a corresponding antenna array"). Petitioner contended that the prior art combinations render the claims obvious even under the Patent Owner's own broad interpretation.

5. Arguments Regarding Discretionary Denial

  • Petitioner argued that discretionary denial is unwarranted. It asserted that General Plastic does not apply because Ericsson has not previously challenged the ’931 patent and is seeking to join an already instituted IPR.
  • Critically, Petitioner stipulated that if the Board institutes this IPR, Ericsson will not pursue the grounds raised in the petition, or any grounds that could have reasonably been raised, in the related district court litigation. Petitioner argued that this Sotera stipulation renders the Fintiv factors for discretionary denial inapplicable.

6. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 28 and 29 of Patent 7,230,931 as unpatentable.