PTAB

IPR2016-01852

RPX Corp v. Pico Byte Systems LLC

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Petition
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1. Case Identification

2. Patent Overview

  • Title: Adaptive Transmission In Multi-Access Asynchronous Channels
  • Brief Description: The ’981 patent discloses a method for communication over a shared medium using a hybrid protocol. The method defines a repeating transmission cycle divided into an "adaptive time-division multiplexing" (TDM) portion for dedicated bandwidth and a "residual" portion for contention-based access, similar to standard Ethernet.

3. Grounds for Unpatentability

Ground 1: Obviousness over Grobicki - Claims 1-6 and 8 are obvious over Grobicki.

  • Prior Art Relied Upon: Grobicki (Patent 5,471,474).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued Grobicki discloses a shared bus protocol that solves the same problem as the ’981 patent using modified TDM techniques. Grobicki’s protocol defines a transmission cycle (a "Block Sync Interval") that includes both a dedicated portion for demand-based and isochronous data and a contention-based portion. Petitioner asserted that Grobicki’s "dedicated" slots map to the ’981 patent's first TDM portion and its "public contention" slots map to the residual portion. The allocation is "adaptive" because Grobicki's system allocator dynamically adjusts slot assignments between contention and dedicated slots based on network loading conditions. For the "alternately repeated" limitation, Petitioner contended it would be obvious to a person of ordinary skill in the art (POSITA) to structure the cycle with the dedicated portion first, followed by the contention portion, and repeat this structure in each cycle.
    • Motivation to Combine (for §103 grounds): Although a single-reference ground, the motivation for the obviousness argument rested on a POSITA’s understanding that arranging the dedicated and contention portions sequentially within a repeating cycle was a logical and predictable design choice for managing network traffic.
    • Expectation of Success (for §103 grounds): Petitioner asserted a POSITA would have a high expectation of success in implementing this arrangement, as both dedicated and contention-based access methods were well-known.

Ground 2: Anticipation by IEEE 1394 - Claims 1-5 are anticipated by IEEE 1394.

  • Prior Art Relied Upon: IEEE Standard for a High Performance Serial Bus ("IEEE 1394").
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that the IEEE 1394 standard, a well-established protocol for serial bus communication, anticipates every limitation of claims 1-5. The standard explicitly defines a repeating transmission cycle divided into two distinct portions: an "isochronous" portion and an "asynchronous" portion. The isochronous portion provides guaranteed bandwidth for time-sensitive data, mapping directly to the ’981 patent's first TDM portion. It is "adaptive" because nodes can allocate and deallocate bandwidth slots at run time. The asynchronous portion, which follows the isochronous portion, is used for contention-based data transfer on a first-come, first-served basis, mapping to the patent's residual portion allocated based on "primacy."

Ground 3: Anticipation by Shaffer - Claims 1 and 6-8 are anticipated by Shaffer.

  • Prior Art Relied Upon: Shaffer (Patent 5,960,001).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted Shaffer, which discloses a method for guaranteeing isochronous data flow on a standard CSMA/CD (e.g., IEEE 802.3 Ethernet) network, anticipates claims 1 and 6-8. Shaffer teaches reserving a predetermined number of time slots for isochronous transmissions, which constitutes the first, adaptive TDM portion of the transmission cycle. This portion is adaptive because the number of reserved slots can be adjusted based on demand. After the reserved isochronous transmissions are complete, the remaining bandwidth is available for standard, non-isochronous contention-based access under the CSMA/CD protocol, which maps to the patent's residual portion. Shaffer explicitly discloses that these cycles are repeated and that nodes back off upon collision detection during the contention phase, meeting limitations of the dependent claims.

4. Key Claim Construction Positions

  • "adaptive": Petitioner proposed the construction "adjusted in size and/or number of slots at run time." This construction was argued to be consistent with the specification's description of an "elastic" TDM scheme and was critical for mapping the dynamic allocation features of the cited prior art.
  • "primacy": Petitioner proposed the construction "a free-for-all scheme or coming first in time." As the term does not appear in the specification outside of claim 1, this construction was based on the patent's description of the residual portion operating like conventional 802.3 Ethernet, where the first node to request access gains control.
  • "logical link channel": For claim 2, Petitioner proposed the construction "transmission cycle opportunity for control or signaling information." This was based on the specification's description of "D-Channels" used for acquiring or relinquishing data payload slots.

5. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 1-8 of the ’981 patent as unpatentable.