PTAB

IPR2018-01777

Sprint Spectrum L.P. v. Intellectual Ventures II LLC

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1. Case Identification

2. Patent Overview

  • Title: Paging in a Wireless Network
  • Brief Description: The ’330 patent describes methods for improving the efficiency of paging a user equipment (UE) in a wireless network, such as a Long-Term Evolution (LTE) network. The invention purports to speed up the connection between a mobile terminal and the Radio Access Network (RAN) by using a network-initiated procedure involving paging indicators on a shared control channel and a corresponding paging message on a shared data channel.

3. Grounds for Unpatentability

Ground 1: Obviousness over LG and Montojo - Claims 1-3, 7-10, 14, 17-20, 24-27, 31, and 34 are obvious over LG in view of Montojo.

  • Prior Art Relied Upon: LG (Patent 8,135,420) and Montojo (Patent 8,914,048).
  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner argued that LG discloses the foundational system for the challenged claims but contains a key deficiency that Montojo remedies. LG teaches a method for paging a UE in idle mode within an LTE system. It describes sending a paging indicator on a fast control channel (e.g., an L1/2 control channel) to alert the UE, which then listens for a full paging message on a separate shared data channel (e.g., DL-SCH). LG recognized that a full, long UE identity (like an IMSI) is too large to be included in the fast control channel indicator and proposed using a "short UE identity." However, Petitioner contended that LG fails to teach how to create this short identity in a way that is efficient and avoids network problems.

      Montojo was asserted to directly address this problem. Montojo teaches an "enhanced paging" method that reduces the bit-length of the UE identifier in the paging indicator. Specifically, Montojo discloses using only a partial UE ID, such as a predetermined number of "least significant bits" (LSBs) of a Radio Network Temporary Identifier (RNTI). This shortened identifier is small enough to be sent on a fast shared control channel (SDCCH). Montojo further taught using a hashing function to map UEs to specific paging occasions, minimizing the "collisions" that could occur when multiple UEs share the same partial ID. Petitioner argued that applying Montojo’s technique of using LSBs as the "short UE identity" within LG’s paging framework renders the claimed invention obvious. For example, claim 1 requires a network device to send a signal derived from an RNTI that indicates a shared channel for the UE; LG provides the network device and shared channel indication, while Montojo provides the specific method of deriving the signal from an RNTI (i.e., using its LSBs).

    • Motivation to Combine: Petitioner asserted that a person of ordinary skill in the art (POSITA), starting with the system in LG, would have been motivated to combine it with Montojo to solve a problem explicitly identified by LG. Both patents operate in the same field of endeavor (paging in wireless networks) and address the same goal: improving power savings and efficiency by reducing the size of the paging indicator. A POSITA reading LG would understand the need for an effective "short UE identity" to enable power-saving DRX cycles. Montojo, titled "Method and Apparatus for Enhanced Paging," provides a direct and well-understood solution to this bit-length problem. The motivation was to implement a known technique (using LSBs for a shorter ID) to improve a known system (LG's paging method) to achieve a predictable and desired result (enhanced battery life for the UE).

    • Expectation of Success: Petitioner argued a POSITA would have had a reasonable expectation of success in combining the references. The outcome of the combination was predictable. Using Montojo’s LSB-based identifier within LG's framework would predictably allow the paging indicator to be sent on a fast control channel, and Montojo’s hashing function would predictably minimize collisions. The result would be a more efficient and power-saving paging system, which was the known goal in the art at the time.

4. Relief Requested

  • Petitioner requested the institution of an inter partes review (IPR) and the cancellation of claims 1-3, 7-10, 14, 17-20, 24-27, 31, and 34 of the ’330 patent as unpatentable.