Microsoft Corp v. Uniloc 2017 LLC

1. Case Identification

• Case #: IPR2020-00102
• Patent #: 6,498,541
• Filed: November 5, 2019
• Petitioner(s): Microsoft Corporation
• Patent Owner(s): Uniloc 2017 LLC
• Challenged Claims: 1

2. Patent Overview

• Title: Communication Bus System and Apparatus and Device for Use in Such a System
• Brief Description: The ’541 patent discloses a method for controlling a bus communication system by detecting the connection or disconnection of a device. The system transmits a wave signal down a transmission line and uses a "wave splitter" to detect a reflected wave, which indicates an impedance mismatch caused by a device being disconnected (an open circuit).

3. Grounds for Unpatentability

Ground 1: Claim 1 is obvious over Lee in view of IEEE 802.3u

• Prior Art Relied Upon: Lee (Patent 5,737,316) and IEEE 802.3u-1995 ("802.3u").
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued Lee discloses a method for controlling a computer network by detecting the connection status of a station. Lee's method, like the ’541 patent, relies on detecting reflected signals caused by impedance mismatches to determine if a communication line is open or properly terminated. Petitioner asserted that Lee’s disclosed “link status means” performs the same function as the ’541 patent’s “wave splitter” by subtracting a reference signal from the transmitted signal to isolate the reflected wave for measurement. This isolated reflected wave is then used to determine the connection status.
  • Motivation to Combine: Petitioner contended that Lee expressly states its method is “especially suited for IEEE standard 802.3u.” A person of ordinary skill in the art (POSITA) implementing an Ethernet system according to the 802.3u standard would have been motivated to incorporate Lee's teachings. Lee's reflection-based detection method offered a superior, faster alternative to the standard's slower "time out" approach for detecting disconnections.
  • Expectation of Success: A POSITA would have had a reasonable expectation of success because Lee's link status output signals were fully compatible with and would cleanly integrate into the overall system architecture and signaling scheme described by 802.3u.

Ground 2: Claim 1 is obvious over USB 1.1 in view of Morris

• Prior Art Relied Upon: Universal Serial Bus Specification Rev. 1.1 ("USB 1.1") and Morris (Patent 6,631,159).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner asserted that USB 1.1 discloses a well-known bus communication system that supports dynamic attachment and removal of devices. Morris discloses a transceiver for use in USB systems that improves upon standard disconnect detection. Morris teaches detecting a cable disconnect by measuring a reflected wave that occurs when a device is unplugged. When the receiving transceiver's termination resistor is no longer present on the line, the impedance mismatch causes a large reflected wave, which is detected by a differential comparator that compares the signal to a predetermined threshold. Petitioner argued that the signal path in Morris, where a return wave is split between a transmitter and a disconnect detector, functions as the claimed "wave splitter."
  • Motivation to Combine: Petitioner argued a POSITA would combine Morris with USB 1.1 because Morris explicitly presents its technology as an enhancement for USB systems. Morris claimed to provide faster disconnect detection that works on both sides of the cable and does not require external resistors, overcoming known disadvantages of the standard USB 1.1 technique. A POSITA would have been motivated to incorporate Morris to achieve these stated benefits.
  • Expectation of Success: A POSITA would have had a reasonable expectation of success in combining the references. The output signal from the Morris disconnect detector was fully compatible with the signaling scheme of USB 1.1 (e.g., the "Disconnect_Detect" signal), allowing for straightforward integration into the standard USB bus management system.

4. Arguments Regarding Discretionary Denial

• Against §314(a) Denial: Petitioner argued against discretionary denial because this was the first IPR petition filed against the ’541 patent. Petitioner noted that the parallel district court litigation was in its early stages, with a trial not scheduled until June 2021, and that an IPR would serve the congressional goal of improving patent quality and limiting litigation costs, especially in a campaign involving numerous patents asserted by the Patent Owner.
• Against §325(d) Denial: Petitioner asserted that denial under §325(d) was inappropriate because the primary prior art references (Lee, 802.3u, USB 1.1, Morris) were neither cited nor considered by the examiner during the original prosecution. The examiner’s analysis of the only cited reference, Ishii, concluded it did not disclose a wave splitter. Since the newly presented art combinations expressly teach using reflected waves and functionally equivalent wave splitters to detect connection status, Petitioner argued the petition raised new issues that the Patent Office had not previously considered.

5. Relief Requested

• Petitioner requested the institution of an inter partes review and the cancellation of claim 1 of Patent 6,498,541 as unpatentable.