Qualcomm Inc v. Rembrandt Wireless Technologies LP

1. Case Identification

• Case #: IPR2020-00509
• Patent #: 8,457,228
• Filed: February 3, 2020
• Petitioner(s): Qualcomm Incorporated
• Patent Owner(s): Rembrandt Wireless Technologies, LP
• Challenged Claims: 21

2. Patent Overview

• Title: Master/Tributary Communication with Multiple Modulation Methods
• Brief Description: The ’228 patent describes a wireless communication system wherein a master transceiver communicates with multiple tributary ("trib") transceivers. The master is capable of using different modulation methods, such as a "type A" modulation for one set of tribs and a "type B" modulation for another.

3. Grounds for Unpatentability

Ground 1: Obviousness over Trompower and Norman - Claim 21 is obvious over Trompower in view of Norman.

• Prior Art Relied Upon: Trompower (Patent 6,132,306) and Norman (Patent 5,737,328).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Trompower disclosed the core elements of the challenged claim. Trompower taught a cellular communication system where mobile terminals dynamically modify transmission parameters, including switching between different modulation methods (e.g., BPSK for mid/slow data rates and QPSK for fast data rates) based on distance from a base station. The mobile terminal acted as the "master," selecting the data rate, and the base stations acted as "tribs." Petitioner contended that Norman, which taught a process for a mobile unit to register with a wireless access point by broadcasting a "find router" packet and sending a registration request, supplied the claimed feature of transmitting a first message (the registration request) to a specific trib. Claim 21's requirement that the first message includes address data was met by Norman's disclosure of a registration packet addressed to a selected base station.
  • Motivation to Combine: A POSITA would combine these references because Trompower explicitly taught that the "registration of mobile terminals may be carried out... using the registration procedures described, for example, in pending U.S. app. Ser. No. 08/539,130," which is the application that issued as the Norman patent. Therefore, applying Norman's known registration method to Trompower's system was expressly suggested and would yield the predictable result of the mobile terminal registering with a selected base station.
  • Expectation of Success: The combination was a straightforward application of a known registration technique to an existing wireless system to achieve a predictable outcome.

Ground 2: Obviousness over Trompower, Norman, and Tymes - Claim 21 is obvious over Trompower and Norman in further view of Tymes.

• Prior Art Relied Upon: Trompower (Patent 6,132,306), Norman (Patent 5,737,328), and Tymes (Patent 5,029,183).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground was presented to address any potential argument that Trompower failed to disclose a clear master/trib relationship. Petitioner asserted Tymes cured any such deficiency by teaching a power-saving system where remote terminals (masters) initiate all communications and only activate their receivers for brief, fixed intervals after transmitting. Base stations (tribs) could only respond and could not initiate communication. This configuration explicitly established a master/trib relationship where the mobile device controls communication to conserve power. The remaining claim elements were met by Trompower and Norman as detailed in Ground 1.
  • Motivation to Combine: A POSITA would combine Tymes with Trompower to improve the battery life of Trompower's portable mobile terminals, a well-known design goal. By configuring Trompower's mobile terminals to operate as Tymes-style masters, their receivers could be deactivated for long periods, significantly reducing power consumption and increasing portability. This was a known technique to improve a similar device.
  • Expectation of Success: A POSITA would have understood that configuring Trompower's mobile terminals as Tymes-style masters was a simple design choice that would operate as expected to conserve power.

Ground 3: Obviousness over Trompower, Norman, and Malkamaki - Claim 21 is obvious over Trompower and Norman in further view of Malkamaki.

• Prior Art Relied Upon: Trompower (Patent 6,132,306), Norman (Patent 5,737,328), and Malkamaki (Patent 5,491,832).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground was presented to address any potential argument that Trompower's use of BPSK and QPSK did not constitute "different types" of modulation. Malkamaki taught a cellular system that used different modulation schemes based on cell size to manage the tradeoff between power efficiency and bandwidth efficiency. Specifically, it disclosed using a power-efficient constant envelope modulation (GMSK) in large cells and a bandwidth-efficient linear modulation (QAM) in small cells. Petitioner argued that substituting Malkamaki's GMSK for Trompower's BPSK would render the system's modulation methods indisputably "different types," as GMSK modulates frequency while QPSK modulates phase and amplitude.
  • Motivation to Combine: A POSITA would substitute GMSK for BPSK in Trompower's system to gain known benefits. GMSK was widely used in the GSM standard, which would lower component costs. Further, GMSK offered better power efficiency than BPSK (critical for battery-powered terminals) and had a more compact output spectrum, allowing for more channels. This was a simple substitution of one known modulation scheme for another to achieve predictable improvements in cost and performance.
  • Expectation of Success: Applying Malkamaki's GMSK in place of Trompower's BPSK was a matter of simple substitution that would yield predictable results in power efficiency and spectral compactness.
• Additional Grounds: Petitioner asserted an additional obviousness challenge (Ground 4) over Trompower in view of Norman, Tymes, and Malkamaki, arguing this combination supplied all elements for the same reasons articulated in the grounds above.

4. Key Claim Construction Positions

• "modulation method being of a different type": Petitioner argued this term should be construed as "different families of modulation techniques... wherein different families may have overlapping characteristics." This construction was proposed to counter the Patent Owner's potential argument that modulations sharing a common characteristic (e.g., BPSK and QAM both varying phase) belong to the same "family" or "type." Petitioner cited intrinsic evidence from dependent claims and extrinsic technical articles showing that modulation "families" like PSK and QAM are considered distinct despite sharing phase modulation characteristics.
• "master" and "slave" / "trib": Petitioner proposed construing "master" as "a device that initiates and controls communication" and "slave" or "trib" as "a device that responds to communication from, and whose communications are controlled by, the master." This construction was argued to be consistent with the specification and broader than a potential Patent Owner construction requiring the master to control "all communications," which Petitioner contended was contradicted by embodiments in the ’228 patent itself.

5. Relief Requested

• Petitioner requested institution of an inter partes review and cancellation of claim 21 of the ’228 patent as unpatentable under 35 U.S.C. §103.