RPX Corp v. Digital Audio Encoding Systems LLC

1. Case Identification

• Case #: IPR2017-00208
• Patent #: 7,490,037
• Filed: November 7, 2016
• Petitioner(s): RPX Corporation
• Patent Owner(s): Digital Audio Encoding Systems, LLC
• Challenged Claims: 1-32

2. Patent Overview

• Title: Method of Encoding Signals, in Particular Digitized Audio Signals
• Brief Description: The ’037 patent discloses methods and apparatuses for encoding signals, such as digitized audio, where the encoding format is selected based on one or more properties of a device that will process the signal. The system determines these properties by transmitting a test signal to the processing device and detecting a response.

3. Grounds for Unpatentability

Ground 1: Claims 1-32 are anticipated by the ’037 patent’s own parent PCT publication

• Prior Art Relied Upon: International Publication No. WO 99/01948 ("PCT Publication").
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that the ’037 patent’s claim to priority is defective. The parent application (’049 application) became abandoned on March 2, 2005, for failure to respond to an Office Action. The application that matured into the ’037 patent was not filed until June 2, 2005, breaking the chain of copendency required under 35 U.S.C. §120. Consequently, the ’037 patent is only entitled to its 2005 filing date. The parent PCT Publication, published in January 1999, is therefore prior art under 35 U.S.C. §102(b). Petitioner asserted that the specification of the PCT Publication is nearly identical to that of the ’037 patent and its claims disclose all limitations of challenged claims 1-32.

Ground 2: Claims 1-2, 10-11, 13, 17, 20-22, 24-26, and 29 are anticipated by Goetz

• Prior Art Relied Upon: Goetz (Patent 5,956,729).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner asserted that Goetz discloses a real-time server-client audio streaming system that anticipates the challenged claims. In Goetz, a server (the claimed "control device") streams encoded audio to a client (the "processing device"). Multiple versions of the audio content, encoded at different bit rates, are available on the server. The optimal encoding format is selected for a particular client by first characterizing the client's network connection. This characterization, which involves transmitting packets to the client to measure properties like packet loss, constitutes the claimed "transmitting a test signal." The server then "detects" a property of the processing device when the client reports back its desired transmission rate, which is based on its network properties (e.g., modem communication rate). The server then selects the audio file with the corresponding encoding format (bit rate) that matches the client's reported rate.
  • Key Aspects: Goetz's disclosure of characterizing a client's network connection by transmitting known packets or a "test audio stream" was argued to meet the "test signal" limitations of the independent claims.

Ground 3: Claims 2-4, 15, and 18-19 are obvious over Goetz in view of Cannon

• Prior Art Relied Upon: Goetz (Patent 5,956,729) and Cannon (Patent 6,014,706).

• Core Argument for this Ground:

  • Prior Art Mapping: Petitioner argued that Goetz teaches the foundational real-time streaming system. Cannon, which also discloses a real-time streaming system, further teaches that a client computer can store received signal packets in a peripheral storage device for later replay without needing to re-request them from the server. This addresses dependent claim limitations related to the processing device also being a "transmitting device" that transmits the encoded signal (e.g., from a reception buffer to a storage device within the client PC).
  • Motivation to Combine: A POSITA would combine Cannon’s teaching with Goetz’s system to gain the benefit of local replay, which reduces server memory and processing requirements, an explicit goal of Goetz. Since both references describe implementing clients on standard personal computers, applying Cannon's storage feature to Goetz's client would be a straightforward modification.
  • Expectation of Success: The combination involved applying a known feature (local storage for replay) from one PC-based streaming system to another, presenting no technical hurdles and thus ensuring a high expectation of success.

• Additional Grounds: Petitioner asserted additional obviousness challenges based on combinations of Goetz with other references to meet further dependent claim limitations, including Kalra (for processor power limitations), Walsh (for user-settable encoding formats), Brandenburg (for psycho-acoustic encoding), Krueger (for memory capacity limitations), RealAudio (for user interface displays), Ferriere (for wireless operation), and Lin (for wireless input devices).

4. Key Claim Construction Positions

• "signal": Petitioner argued this term should be construed broadly as "a transmission of information." This construction allows network communications, such as queries, responses, or streams of data packets used for measuring network statistics in the prior art, to satisfy the "signal" and "test signal" limitations.
• "test signal": Consistent with the above, Petitioner argued this term means "a transmission of information transmitted as part of determining the presence or quality of something." This allows conventional network diagnostic techniques, like sending known packets to measure packet loss as taught in Goetz, to be considered a "test signal."

5. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 1-32 of the ’037 patent as unpatentable.