PTAB

IPR2018-01329

Intel Corp v. Qualcomm Inc

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Power Tracking for Carrier Aggregated Signals
  • Brief Description: The ’675 patent discloses a system for improving the efficiency of radio frequency (RF) transmitters in mobile devices. It describes a technique for transmitting multiple "carrier aggregated" signals simultaneously using a single power amplifier (PA) and a single power tracking supply generator, which is intended to reduce circuit complexity, power consumption, and cost compared to systems using multiple transmitters.

3. Grounds for Unpatentability

Ground 1: Obviousness over Yu, Wang, and Choi - Claims 28-30 are obvious over Yu in view of Wang and Choi.

  • Prior Art Relied Upon: Yu (European Application # EP 2 442 440 A1), Wang ("Design of Wide-Bandwidth Envelope-Tracking Power Amplifiers for OFDM Applications," 2005 IEEE publication), and Choi ("Envelope Tracking Power Amplifier Robust to Battery Depletion," 2010 IEEE publication).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that the combination of these three references teaches every element of the challenged claims.
      • Yu was asserted to teach the core concept of the ’675 patent: an apparatus that uses a single power amplifier and a single control unit to process and transmit multiple input signals (S1, S2) simultaneously. Yu’s control unit generates a single control signal (CTRL) based on the combined input signals to modulate the power supply, a technique known as envelope or power tracking.
      • Wang was introduced to supply the teaching of using inphase (I) and quadrature (Q) components and Orthogonal Frequency Division Multiplexing (OFDM) signals, which are explicit limitations in the challenged claims but not explicitly detailed in Yu. Petitioner contended that a person of ordinary skill in the art (POSITA) would understand Yu’s “digital baseband signals” to be I/Q signals. Wang explicitly discloses a “complex baseband signal” with I/Q components for envelope tracking and specifically addresses its use for OFDM applications.
      • Choi was used to teach the specific structure of the power supply generator, a limitation recited in a means-plus-function format. While Yu disclosed a power supply module at a high level, Choi taught a specific and efficient implementation known as a "hybrid switching amplifier" (HSA). This HSA, comprising a linear amplifier and a buck converter (a type of switcher), was argued to be analogous to the power supply generator structure described in the ’675 patent.
    • Motivation to Combine (for §103 grounds):
      • A POSITA would combine Yu and Wang as they address the same problem in the same technical field (envelope tracking for RF power amplifiers). Wang provided a well-known and efficient method (I/Q processing and OFDM) to implement the high-level system described in Yu, offering predictable benefits such as improved data rates and noise immunity.
      • A POSITA would be motivated to implement Yu's power supply generator using the specific HSA circuit from Choi to gain known advantages of high efficiency and robustness to battery depletion. These benefits are particularly important for mobile devices, the target application for this technology. The references were complementary, with Yu providing the high-level architecture and Choi providing a specific, performance-enhancing implementation.
    • Expectation of Success (for §103 grounds): A POSITA would have had a high expectation of success because the combination involved applying known techniques (I/Q signaling, OFDM) and components (HSA power supplies) to a known system architecture (multi-signal envelope tracking) to achieve predictable results and well-understood benefits.

4. Key Claim Construction Positions

  • Petitioner stated it applied claim constructions adopted by the Administrative Law Judge (ALJ) in a parallel ITC investigation, which it contended were favorable to its invalidity arguments.
  • "plurality of carrier aggregated transmit signals" (claims 28-30): Construed as "signals for transmission on multiple carriers at the same time to increase bandwidth for a user." Petitioner argued Yu’s disclosure of transmitting two signals (S1, S2) on different frequencies met this limitation.
  • "power tracker" (claim 28): Construed as a "component in a voltage generator that computes the power requirement." Petitioner mapped this to Yu's control unit (100).
  • "single power tracking signal" (claims 28-30): Construed as "one (single-ended) power tracking signal." Petitioner asserted Yu's CTRL signal met this construction.
  • Means-Plus-Function Terms: Petitioner argued that for several means-plus-function limitations (e.g., "means for determining a single power tracking signal"), the corresponding structure in the ’675 patent (e.g., power tracker 582) was disclosed as a simple, undescribed rectangle. It contended that the more detailed structures in the prior art, such as Yu's control unit, were at least structural equivalents.

5. Key Technical Contentions (Beyond Claim Construction)

  • Implicit I/Q Disclosure: A central technical contention was that even though Yu did not explicitly name I/Q components, a POSITA would have inherently understood its "digital baseband signals" to use I/Q modulation. This was because it was the standard practice for the RF communication systems (e.g., UMTS, LTE) that Yu’s invention was designed for.
  • Power Calculation Proxy: Petitioner contended that Yu's method of calculating and summing the absolute values of the voltage signals (|S1| + |S2|) was a direct and well-understood proxy for the signal's power. It argued that modifying this to calculate the magnitude squared (I² + Q²), which is directly proportional to power, would have been a trivial and obvious design choice. This was used to address claim limitations requiring a determination of "overall power."

6. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 28-30 of the ’675 patent as unpatentable under 35 U.S.C. §103.