PTAB

IPR2016-01494

TCT Mobile US Inc v. Wireless Protocol Innovations Inc

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1. Case Identification

2. Patent Overview

  • Title: Protocol for Allocating Upstream Slots Over a Link in a Point-to-Multipoint Communication System
  • Brief Description: The ’991 patent discloses a method for managing uplink bandwidth requests in a point-to-multipoint communication network. The method aims to reduce contention traffic for non-bursty data (e.g., VoIP) by introducing a "Grant Pending Absent" state, which allows a remote station to resume data transmission without re-entering a contention process.

3. Grounds for Unpatentability

Ground 1: Obviousness over Abi-Nassif and DOCSIS 1.1 - Claims 1 and 3-5 are obvious over Abi-Nassif in view of DOCSIS 1.1.

  • Prior Art Relied Upon: Abi-Nassif (WO 99/61993) and DOCSIS 1.1 (Data-Over-Cable Service Interface Specifications, SP-RFIv1.1-I02-990731).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Abi-Nassif, which describes a MAC protocol for a shared medium network, discloses a state machine nearly identical to that claimed in the ’991 patent. Abi-Nassif’s “ACTIVE” state allegedly maps to the claimed “grant pending” state by awaiting and receiving a bandwidth grant, transmitting data, and using piggybacking for further requests. Abi-Nassif’s “INACTIVE” state allegedly maps to the “grant pending absent” state, where a user device awaits data and can receive a contention-free opportunity (unicast poll) to request bandwidth. Petitioner contended the only element not explicitly taught by Abi-Nassif is transitioning from the “grant pending absent” state to a separate “idle” state after a timeout period.
    • Motivation to Combine: Petitioner asserted that DOCSIS 1.1 provides the missing timeout feature. DOCSIS 1.1 discloses a configurable "Timeout for Active QoS Parameters" that deems a service flow "inactive" (functionally idle) if its resources remain unused for a specified duration. A POSITA would combine these references because Abi-Nassif’s preferred embodiment is based on the earlier DOCSIS 1.0 standard. It would have been a predictable and simple step to incorporate the improved timeout and QoS features of the next-generation, backwards-compatible DOCSIS 1.1 standard to enhance network efficiency.
    • Expectation of Success: A POSITA would have had a high expectation of success because DOCSIS 1.1 was designed to be interoperable with the DOCSIS 1.0 systems on which Abi-Nassif was based.

Ground 2: Obviousness over DOCSIS 1.1 and Abi-Nassif - Claims 1 and 3-5 are obvious over DOCSIS 1.1 in view of Abi-Nassif.

  • Prior Art Relied Upon: DOCSIS 1.1 and Abi-Nassif (WO 99/61993).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground reverses the primary and secondary references. Petitioner argued that DOCSIS 1.1, a comprehensive specification for data-over-cable systems, teaches all the claimed state transitions. The “grant pending” state is taught by DOCSIS 1.1’s Non-Real-Time Polling Service (nrtPS), where a cable modem requests and receives bandwidth. The “grant pending absent” state is met when the modem, though still actively polled, has no data to send. The transition to an “idle” state is taught by the configurable timeout that deactivates the service flow. The dependent claims are met by DOCSIS 1.1’s provisions for contention-based requests (“deferring state”) and piggybacking.
    • Motivation to Combine: The primary argument against DOCSIS 1.1 alone is that it is a standard for wired cable networks, while the ’991 patent is directed to wireless technology. Petitioner asserted that Abi-Nassif supplies the motivation to apply the DOCSIS 1.1 protocol in a wireless context. Abi-Nassif explicitly teaches that its DOCSIS-based MAC protocol can be implemented over a wireless physical medium (“air, atmosphere, or space”). Therefore, a POSITA seeking to implement a robust, feature-rich MAC protocol for a wireless system would have been motivated to adapt the well-documented DOCSIS 1.1 standard, with a high expectation of success.

Ground 3: Obviousness over Sen, POAPA, and Rydnell - Claims 1 and 3-5 are obvious over Sen in view of POAPA and Rydnell.

  • Prior Art Relied Upon: Sen (Patent 6,466,544), POAPA (Patent Owner’s Admitted Prior Art on “Piggybacking”), and Rydnell (Patent 6,665,307).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Sen, which discloses a wireless GPRS MAC protocol, teaches the core invention. Sen’s “Packet Standby” state allows a mobile station to remain connected and quickly resume transmission via a control packet without re-contending, mapping to the “grant pending absent” state. Sen’s “Packet Transfer” state maps to the “grant pending” state. To the extent Sen does not explicitly disclose piggybacking for further bandwidth requests, Petitioner supplemented with POAPA, which the ’991 patent admits is a known technique for this purpose.
    • Motivation to Combine: Petitioner used Rydnell to supply the specific timeout limitation. Sen discloses transitioning to an idle state when a “release timer expires,” but Rydnell was cited for its more specific teaching of an inactivity timer that, upon expiry, moves a mobile station to a power-saving sleep mode (an idle state). A POSITA would combine Sen with Rydnell’s power-saving timeout mechanism to achieve the predictable result of improved battery life for the mobile station, a key concern in wireless device design. Combining Sen with the admitted prior art of piggybacking (POAPA) was argued to be a simple application of a known technique to improve efficiency.

4. Key Claim Construction Positions

  • Preamble is Not Limiting: Petitioner argued that the preamble of claim 1 is not limiting and merely states an intended use. The structural elements in the preamble are duplicated in the claim body, and the preamble was not relied upon during prosecution to overcome prior art.
  • Claims Not Limited to Wireless: Anticipating a contrary argument from the Patent Owner, Petitioner contended that the broadest reasonable interpretation of claim terms like "point-to-multipoint communication," "link," and "base station controller (BSC)" encompasses both wired and wireless systems. The patent itself avoids limiting these terms to wireless implementations, and the claims do not contain any explicit "wireless" or "cellular" limitations.

5. Key Technical Contentions (Beyond Claim Construction)

  • Cable and Wireless are Analogous Arts: A central contention was that prior art from the field of data-over-cable (like DOCSIS 1.1) is analogous to the wireless communication field of the ’991 patent. Petitioner argued that both fields address the same fundamental problems of MAC-layer contention and Quality of Service (QoS) management in point-to-multipoint networks. Evidence was presented showing that by the time of the patent’s filing, the IEEE 802.16 wireless standard was actively incorporating MAC protocols based on DOCSIS, demonstrating that a POSITA would have readily looked to the cable art for solutions.

6. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 1 and 3-5 of the ’991 patent as unpatentable.