PTAB

IPR2018-01556

HTC Corp v. Invt SPE Inc

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Communication Terminal Apparatus and Communication Method
  • Brief Description: The ’587 patent discloses methods for improving the reliability of High Data Rate (HDR) wireless communications. The technology focuses on how a communication terminal reports measured downlink channel quality to a base station using a Data Rate Control (DRC) signal, converting this signal into a codeword using an Unequal Error Protection (UEP) scheme where the level of error protection is proportional to the reported channel quality.

3. Grounds for Unpatentability

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

  • Prior Art Relied Upon: Padovani (PCT Application # PCT/US98/23428) and Gils (a 1988 Ph.D. dissertation titled “Design of error-control coding schemes for three problems of noisy information transmission, storage and processing”).
  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner argued that Padovani disclosed the foundational framework of the challenged claims. Padovani taught a CDMA system where a mobile station measures the forward link channel quality (e.g., Carrier-to-Interference ratio or C/I) and transmits this information back to a base station as a DRC message. Padovani explicitly recognized the importance of encoding this DRC message to ensure low error probability and avoid impacting system throughput. However, Padovani only disclosed a generic block encoder.

      Petitioner asserted that Gils provided the missing element: the use of sophisticated Linear Unequal Error Protection (LUEP) codes. Gils taught designing error-control schemes that provide different levels of protection to different parts of a message based on their importance. For example, Gils taught protecting the most significant bits of a message more robustly than less significant bits. Petitioner contended that applying the specific LUEP coding schemes from Gils to the DRC message in Padovani would render the claims obvious. Specifically for claim 1, Petitioner argued that a POSITA would select different coding schemes from tables in Gils to encode different DRC values, resulting in codewords whose "code word minimum distance" is proportional to the channel quality they represent. For claim 4, applying an LUEP scheme from Gils would inherently make the most significant bit of the DRC message "less susceptible to errors" by assigning it a greater minimum Hamming distance.

    • Motivation to Combine: Petitioner asserted a strong motivation to combine these references. A person of ordinary skill in the art (POSITA), starting with Padovani’s system and its recognized need for reliable DRC message transmission, would have looked to well-known error-correction literature like Gils to improve upon Padovani’s generic encoder. Gils directly addressed the problem of protecting important data in noisy transmissions. Furthermore, Padovani’s system involved a non-linear distribution of data rates, meaning an error in a DRC message corresponding to a high data rate would cause a much more significant drop in performance than an error at a low data rate. This created a clear incentive to provide stronger, unequal error protection for DRC messages indicating better channel quality, a solution explicitly taught by Gils.

    • Expectation of Success: Petitioner argued that a POSITA would have had a reasonable expectation of success. The combination involved applying a known error-correction technique (Gils) to a known data transmission problem (in Padovani) to achieve a predictable improvement in reliability. The principles of LUEP were well-established, and Gils provided concrete examples and tables of optimal codes that could be readily implemented.

4. Key Claim Construction Positions

  • "code word minimum distance" (Claim 1): Petitioner proposed this term be construed to mean "the minimum number of bits by which a particular code word differs with respect to all other code words," based on the patent’s specification.
  • "is proportional to the degree of measured downlink channel quality" (Claim 1): Petitioner argued this phrase should be construed to mean that the code word minimum distance "increases as the downlink channel quality increases at least within a certain range." This construction was based on examples in the ’587 patent’s specification (e.g., FIG. 7), where the minimum distance does not strictly increase at every step but shows a clear positive correlation.

5. Relief Requested

  • Petitioner requests institution of an inter partes review (IPR) and cancellation of claims 1-4 of the ’587 patent as unpatentable.