PTAB

IPR2018-01557

HTC Corp v. Invt SPE Inc

Log In
Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Unequal Error Protection for Wireless Communication Control Signals
  • Brief Description: The ’590 patent describes a method for improving the reliability of transmitting communication mode information, such as a Data Rate Control (DRC) signal, from a communication terminal to a base station. The invention purports to solve issues with transmission errors by applying unequal error protection (UEP), where information corresponding to better downlink channel quality is converted into a code word with a greater code word minimum distance for enhanced protection.

3. Grounds for Unpatentability

Ground 1: Claims 1-4 are obvious over Padovani in view of Gils.

  • Prior Art Relied Upon: Padovani (PCT Application No. PCT/US98/23428) and Gils ("Design of error-control coding schemes for three problems of noisy information transmission, storage and processing,” Ph.D. dissertation, 1988).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Padovani disclosed a Code Division Multiple Access (CDMA) system where a mobile station measures the forward link channel quality (C/I ratio) and transmits an encoded DRC message to a base station. This DRC message can contain the actual C/I measurement, which may be represented as a value with an integer part (an "upper digit") and a fractional part (a "lower digit"). Petitioner contended that Gils taught the fundamental principles of linear unequal error protection (LUEP), describing how to design codes that provide stronger protection to more important parts of a message, such as higher-order digits in numerical data. The combination of Padovani's system with Gils's coding theory was alleged to teach all limitations of claims 1-4, including a "measurer" (Padovani's mobile station), a "coder" (Padovani's DRC encoder modified with Gils's teachings), and a "transmitter."
    • Motivation to Combine: Petitioner asserted that a Person of Ordinary Skill in the Art (POSITA) would combine these references to solve a known problem. Padovani recognized the importance of the DRC message's integrity for system throughput. Gils provided a well-known solution for protecting data where some parts are more critical than others. A POSITA would have been motivated to apply the UEP schemes from Gils to Padovani's DRC message because an error in the integer portion of the C/I value would have a significantly greater negative impact on data rate selection than an error in the fractional portion. This combination represented applying a known technique to improve a known system for its intended purpose.
    • Expectation of Success: A POSITA would have had a reasonable expectation of success because applying Gils's established error-control coding schemes to Padovani's communication system was a predictable and straightforward implementation of known engineering principles.

Ground 2: Claims 5-8 are obvious over Padovani in view of Gils and Olofsson.

  • Prior Art Relied Upon: Padovani (PCT Application No. PCT/US98/23428), Gils (Ph.D. dissertation, 1988), and Olofsson (Patent 6,167,031).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground built upon the combination of Padovani and Gils from Ground 1 to argue the unpatentability of method claims 5-8. The additional reference, Olofsson, was introduced primarily to teach the claim limitation of assigning a downlink channel "on a time division basis." Petitioner argued that Olofsson disclosed link adaptation methods that dynamically change modulation, channel coding, and the number of assigned time slots based on channel conditions (e.g., C/I ratio) to optimize performance. While Padovani already taught a system that partitioned data into packets transmitted over time slots, Olofsson explicitly taught using this time-slotted structure for assigning the downlink channel itself. The remaining limitations—encoding information composed of an upper and lower digit with unequal protection—were met by the combination of Padovani and Gils, as argued in Ground 1.
    • Motivation to Combine: Petitioner contended that a POSITA would have been motivated to combine Olofsson with the Padovani/Gils system to further improve efficiency and achieve optimal performance. Both Padovani and Olofsson sought to improve digital communication systems by adapting to C/I conditions. Since Padovani's system was already based on time slots, a POSITA would have found it obvious to incorporate Olofsson's more specific method of assigning the downlink channel on a time division basis to enhance the system's link adaptation capabilities.
    • Expectation of Success: The combination was presented as predictable, as it involved integrating a known link adaptation strategy (Olofsson) into a compatible communication system (Padovani) while using established coding techniques (Gils) to ensure reliability.

4. Key Claim Construction Positions

  • "code word minimum distance" (Claims 1 and 5): Petitioner proposed that this term should be construed as "the minimum number of bits by which a particular code word differs with respect to all other code words." This construction was based directly on the definition provided in the ’590 patent’s specification and was argued to be critical for mapping the teachings of Gils, which described error protection in terms of Hamming distance and separation vectors, onto the limitations of the challenged claims.

5. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 1-8 of the ’590 patent as unpatentable.