TCT Mobile Inc v. Wireless Protocol Innovations Inc

1. Case Identification

• Case #: IPR2016-01492
• Patent #: 6,381,211
• Filed: July 26, 2016
• Petitioner(s): TCT Mobile, Inc. & TCT Mobile (US) Inc.
• Patent Owner(s): Wireless Protocol Innovations, Inc.
• Challenged Claims: 11, 13-15, 19-24, 26-28

2. Patent Overview

• Title: Techniques for Processing Data in a Wireless Telecommunications System
• Brief Description: The ’211 patent relates to techniques for processing data transmitted over a wireless link between a central terminal and multiple subscriber terminals. The technology employs a combination of code-division multiplexing (CDM) to create multiple orthogonal channels on a single frequency and time-division multiplexing (TDM) within those channels to increase the number of supported users and improve network efficiency.

3. Grounds for Unpatentability

Ground 1: Anticipation of Claims 11, 13-15, 19, 24, 27-28 by Eizenhöfer

• Prior Art Relied Upon: Eizenhöfer (Patent 4,763,322).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Eizenhöfer, a patent for a cellular digital radio transmission system, discloses every limitation of the challenged claims. Eizenhöfer was said to teach a system using a combination of CDM, TDM, and frequency-division multiplexing. Petitioner asserted that Eizenhöfer's disclosure of separating channels using different "orthogonal" codewords on a single carrier frequency meets the "orthogonal channels" limitation of independent claim 11. Furthermore, Petitioner contended that Eizenhöfer's teaching of allocating time slots of varying durations to accommodate different services (e.g., telefax, teletext, computer communications) based on their bandwidth requirements directly corresponds to the key claim limitation of allocating a time slot "based on a type of data of the data item." Arguments for dependent claims followed from this core mapping, addressing features like flexible allocation based on subscriber demand.

Ground 2: Anticipation of Claims 11, 13-15, 19-24, 26-28 by Miller

• Prior Art Relied Upon: Miller (WO 93/15573).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner asserted that Miller, which describes a "multiple division multiple access" (MDMA) technique combining CDMA and TDMA, anticipates all challenged claims. Petitioner argued that Miller describes its CDMA technique as an "orthogonal multiplexing technique," thereby disclosing the claimed "orthogonal channels." To meet the limitation of allocating time slots based on data type, Petitioner pointed to Miller's disclosure of dynamically adapting the data transmission format "according to the nature of the traffic to be carried." Specifically, Miller teaches allocating a different number of time slots to users based on the bandwidth requirements of the requested digital service (e.g., voice, fax, video conferencing, telemetry), which Petitioner argued is an allocation based on the type of data. Petitioner also mapped Miller's disclosure of a low-data-rate "hailing channel" used for control signaling to dependent claims requiring a second, lower-rate orthogonal channel.

Ground 3: Obviousness of Claims 20-23 over Eizenhöfer, Masui, and Gilhousen

• Prior Art Relied Upon: Eizenhöfer (Patent 4,763,322), Masui (Patent 6,269,088), and Gilhousen (WO 95/03652).

• Core Argument for this Ground:

  • Prior Art Mapping: Petitioner argued that even if Eizenhöfer alone does not anticipate the claims, the combination with Masui and Gilhousen renders claims 20-23 obvious. Eizenhöfer provided the base system combining CDMA and TDMA. Masui was cited for its teaching of using a separate, orthogonal "reply channel" to transmit control information (i.e., identifying which traffic channel a terminal should use). Gilhousen was cited for teaching a technique to create orthogonal channels with different, variable data rates by using codes of varying lengths, which is particularly useful for creating lower-rate control channels to conserve bandwidth.
  • Motivation to Combine: Petitioner argued that a person of ordinary skill in the art (POSITA) would combine these references to improve the efficiency and throughput of Eizenhöfer's system, as all three references address the same problem of optimizing channel capacity. A POSITA would incorporate Masui’s use of a dedicated orthogonal control channel into Eizenhöfer to improve signaling efficiency. A POSITA would then further modify this system with Gilhousen's teachings to make the control channel a lower data rate channel, thereby freeing up more bandwidth for user data and further optimizing the system.
  • Expectation of Success: The combination involved applying known multiplexing and channel management techniques from the same field of digital communications, leading to predictable improvements in system efficiency.

• Additional Grounds: Petitioner asserted an additional obviousness challenge against claim 26 based on the combination of Eizenhöfer and Masui.

4. Key Claim Construction Positions

• "subscriber terminal": Petitioner proposed this term should be construed to include both fixed-location and mobile devices, consistent with a position advocated by the prior patent owner in district court litigation.
• "orthogonal channels": Petitioner proposed this term means "a set of channels created using orthogonal codes," also noting this construction was agreed to by the prior patent owner in litigation.
• "time slot": Petitioner proposed this term means "an interval of time," arguing against any narrower construction that would require a single wireless link per time slot.

5. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial under 35 U.S.C. §325(d) would be inappropriate. It contended that the primary prior art references Eizenhöfer and Masui were never considered by the USPTO during either original prosecution or a subsequent ex parte reexamination. While Miller was considered during reexamination, Petitioner argued the Examiner was not presented with the most relevant disclosures regarding orthogonal channels, and therefore the merits of the Miller-based ground had not been properly evaluated.

6. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 11, 13-15, 19-24, and 26-28 of the ’211 patent as unpatentable.