PTAB

IPR2018-01557

HTC Corporation v. INVT SPE INC.

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1. Case Identification

2. Patent Overview

  • Title: Communication Terminal Apparatus and Coding and Transmission Method
  • Brief Description: The ’590 patent discloses a method for improving reliability in High Data Rate (HDR) wireless communication systems. The invention focuses on encoding a data rate control (DRC) signal, which indicates downlink channel quality, into a code word. To reduce transmission errors, the "code word minimum distance" is varied based on the channel quality, providing greater protection for signals corresponding to better channel conditions.

3. Grounds for Unpatentability

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

  • Prior Art Relied Upon: Padovani (PCT Application No. PCT/US98/23428) and Gils (a 1988 Ph.D. dissertation).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Padovani discloses a CDMA communication system where a mobile terminal measures the downlink channel quality (C/I ratio) and transmits this information back to the base station as a DRC message. This C/I measurement can be understood as comprising an "upper digit" (the more significant integer portion) and a "lower digit" (the less significant fractional portion). Gils discloses the fundamental principles of linear unequal error protection (LUEP) codes. Gils explicitly teaches designing codes to provide different levels of error protection to different parts of a message, such as giving more important bits (e.g., higher-order digits) greater protection by using encoding schemes that result in a larger Hamming distance (the claimed "code word minimum distance") or by assigning them a larger number of bits.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine Gils’s well-known UEP coding schemes with Padovani’s DRC transmission method. The motivation would be to solve the known problem of ensuring the reliability of the DRC message, as an error in the more significant "upper digit" of the channel quality information would have a more detrimental impact on system performance than an error in the "lower digit." Applying Gils’s targeted error protection was a known solution to a known problem.
    • Expectation of Success: A POSITA would have a reasonable expectation of success in this combination. Applying a standard error-correction coding theory (Gils) to a standard communication control message (Padovani's DRC) to achieve the predictable benefit of improved data integrity was a straightforward application of known principles.

Ground 2: Obviousness over Padovani, Gils, and Olofsson - 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 (a 1988 Ph.D. dissertation), and Olofsson (Patent 6,167,031).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground builds upon Ground 1, incorporating Olofsson to address the method claims (5-8) which involve a base station assigning a downlink channel on a time-division basis. Padovani and Gils provide the core teachings for using UEP to encode the C/I information, as detailed in Ground 1. Padovani itself teaches a system where data is partitioned into packets and transmitted in time slots. Olofsson further teaches link adaptation methods for dynamically changing modulation and channel coding schemes, including the number of time slots, based on measured C/I conditions to optimize performance over a broad range of conditions.
    • Motivation to Combine: A POSITA would be motivated to improve the overall efficiency of the system described in Padovani. Olofsson provides an explicit method for achieving this by adapting the downlink channel assignment (including time slots) based on the very C/I measurements that Padovani's system generates. A POSITA would combine Olofsson's link adaptation teachings with the Padovani/Gils framework to create a more robust and efficient communication method, where the UEP-coded channel information is used to dynamically assign downlink resources.
    • Expectation of Success: The combination would yield predictable results. Integrating Olofsson's established link adaptation techniques into Padovani's communication system, which already measures the necessary C/I parameters, would be a logical step for a POSITA seeking to optimize system throughput and efficiency.

4. Key Claim Construction Positions

  • "code word minimum distance" (Claims 1 and 5): Petitioner contended that, for the purposes of the inter partes review (IPR), this term should be construed according to its explicit definition in the ’590 patent specification. The patent defines "code word distance" as "the number of bits that differ between code words" and "code word minimum distance" as "the minimum number of bits by which a particular code word differs with respect to all other code words." This construction is critical because it directly aligns with the well-understood concept of "minimum Hamming distance" used in coding theory, which is the exact concept Gils teaches manipulating to provide unequal error protection.

5. Relief Requested

  • Petitioner requests institution of an IPR and cancellation of claims 1-8 of Patent 6,760,590 as unpatentable under 35 U.S.C. §103.