Samsung Electronics Co Ltd v. Empire Technology Development LLC

1. Case Identification

• Case #: IPR2024-00896
• Patent #: 8,798,120
• Filed: June 12, 2024
• Petitioner(s): Samsung Electronics Co., Ltd.; Samsung Electronics America, Inc.
• Patent Owner(s): Empire Technology Development LLC
• Challenged Claims: 25-29

2. Patent Overview

• Title: System and Method for Communication Mode Selection
• Brief Description: The ’120 patent describes a wireless communication system for a mobile station that adaptively selects between a multiple-input-multiple-output (MIMO) mode and a single-input-multiple-output (SIMO) transmission mode. The selection is governed by a control signal based on parameters such as transmission circuitry power consumption, idle power consumption, and the number of users in the system to optimize energy efficiency.

3. Grounds for Unpatentability

Ground 1: Obviousness over Li and Siam - Claims 25, 27, and 28 are obvious over Li in view of Siam.

• Prior Art Relied Upon: Li (Application # 2006/0067263) and Siam (a 2006 conference paper titled “Adaptive Multi-antenna Power Control in Wireless Networks”).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Li teaches the core elements of independent claim 25, including a mobile station with multiple antennas and circuitry, and a controller that receives a signal to switch between communication modes (e.g., MIMO and SIMO) to reduce power consumption, including in an idle state. Siam was asserted to supply the missing limitation of basing the control signal on the power consumption of the transmission circuitry. Siam explicitly taught a protocol for selecting an optimal transmit mode by analyzing the trade-off between lower RF transmission energy in MIMO mode and its higher circuit energy consumption.
  • Motivation to Combine: A POSITA would combine Li and Siam to improve Li’s power-saving mode-switching system. Siam’s detailed protocol, which explicitly considers both transmission and circuit power consumption, provided a known method to optimize the mode selection already taught by Li, thereby enhancing battery life, a shared goal of both references.
  • Expectation of Success: A POSITA would have a high expectation of success because both references address the same problem of power inefficiency in compatible wireless systems (e.g., IEEE 802.11) using predictable mode-switching techniques.

Ground 2: Obviousness over Li-Siam and Cui-2003 - Claims 25, 27, and 28 are obvious over the combination of Li and Siam in view of Cui-2003.

• Prior Art Relied Upon: Li (Application # 2006/0067263), Siam (2006 conference paper), and Cui-2003 (a 2003 conference paper titled “Modulation Optimization Under Energy Constraints”).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground built upon the Li-Siam combination to further strengthen the argument for claim 25’s limitation requiring the control signal to be based on "idle power consumption." Petitioner contended that Cui-2003 explicitly taught modeling total energy consumption by considering a transceiver’s distinct power states: active mode, sleep mode, and transient mode. A POSITA would have understood Cui-2003’s "sleep mode" to be analogous to the claimed "idle mode," where circuits are powered but not actively transmitting.
  • Motivation to Combine: A POSITA would be motivated to incorporate Cui-2003’s teachings into the Li-Siam system to create a more robust power optimization algorithm. By explicitly accounting for power consumed during idle periods, as detailed in Cui-2003, the system could make more efficient mode-switching decisions, further preserving battery life.
  • Expectation of Success: Success was expected because all three references address energy optimization in standard wireless communication networks. Integrating Cui-2003’s explicit idle-power modeling was a logical and predictable enhancement to the system proposed by combining Li and Siam.

Ground 3: Obviousness over Li-Siam and Tiirola - Claim 29 is obvious over the combination of Li and Siam in view of Tiirola.

• Prior Art Relied Upon: Li (Application # 2006/0067263), Siam (2006 conference paper), and Tiirola (a 2003 conference paper titled “Performance of a UMTS Uplink MIMO Scheme”).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground targeted independent claim 29, which is identical to claim 25 except it requires the control signal to be based on "a number of users of the communications system" instead of idle power consumption. Petitioner asserted that Tiirola directly supplied this teaching. Tiirola analyzed and simulated uplink performance, demonstrating that noise levels and the relative advantage of MIMO over SIMO are directly affected by the number of active users. Specifically, Tiirola showed that the performance benefit of MIMO mode increases as the number of users grows.
  • Motivation to Combine: A POSITA would combine Tiirola’s teachings with the power-aware Li-Siam system to create a more comprehensive optimization strategy. The Li-Siam combination focused on power consumption, while Tiirola addressed performance degradation due to user load. A POSITA would combine them to balance power efficiency with performance in a real-world multi-user environment, selecting SIMO for power savings with few users but switching to MIMO to handle noise and maintain throughput with many users.
  • Expectation of Success: Combining the references was asserted to be predictable. The trade-off between power consumption (Li-Siam) and user-load-dependent performance (Tiirola) was a known engineering challenge, and integrating these considerations was a straightforward optimization.
• Additional Grounds: Petitioner asserted additional obviousness challenges against claim 26, arguing the control signal being based on "a correlation in the communications channel" was obvious over the Li-Siam combination in view of Wu (Application # 2007/0171808), which taught selecting SIMO mode in the presence of high channel correlation.

4. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial under 35 U.S.C. §325(d) would be inappropriate. The petition contended that none of the primary prior art references (Li, Siam, Cui-2003, Tiirola, Wu) were cited or substantively considered during the original prosecution. Petitioner further argued that the examiner’s reasons for allowance relied on the very limitations—"idle power consumption" and "number of users"—that are explicitly taught by the new art, suggesting the previous examination was materially incomplete.

5. Relief Requested

• Petitioner requested institution of an inter partes review and cancellation of claims 25-29 of Patent 8,798,120 as unpatentable.