Askeladden LLC v. Encoditech LLC

1. Case Identification

• Case #: IPR2017-00452
• Patent #: 6,321,095
• Filed: December 8, 2016
• Petitioner(s): Askeladden L.L.C.
• Patent Owner(s): Encoditech, LLC
• Challenged Claims: 1-8

2. Patent Overview

• Title: Wireless Communications Approach
• Brief Description: The ’095 patent discloses methods and systems for establishing direct, secure wireless communications between mobile stations without requiring intermediary devices like base stations. The technology uses a composite FDMA/TDMA protocol for handshaking and a hybrid encryption technique for security.

3. Grounds for Unpatentability

Ground 1: Obviousness over Chieu and Ford - Claims 1 and 3-6 are obvious over Chieu in view of Ford.

• Prior Art Relied Upon: Chieu (Patent 5,515,366) and Ford (Patent 5,481,613).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Chieu taught the core method of establishing direct, base-station-free communication between mobile devices using a nearly identical handshaking protocol. This protocol involved selecting a channel, transmitting a request signal, receiving an acknowledgment, and establishing a direct session. However, Chieu did not specify a particular encryption technique, merely providing for the exchange of security information. Ford was asserted to fill this gap by explicitly describing the well-known "hybrid encryption" technique, where an asymmetric public/private key system is used to securely distribute a symmetric key for bulk data encryption.
  • Motivation to Combine: A POSITA seeking to secure the direct communication system taught by Chieu would have been motivated to implement an encryption method. Ford confirmed that at the time of the invention, there was a finite, predictable set of solutions (symmetric, asymmetric, hybrid). A POSITA would combine Chieu's protocol with Ford's hybrid encryption to gain the known benefits of both systems: the simple key distribution of asymmetric encryption and the low processing overhead of symmetric encryption for bulk data like voice communications.
  • Expectation of Success: Petitioner contended that combining a known communication protocol (Chieu) with a standard, well-understood encryption technique (Ford) was a routine task for a POSITA and would have yielded the predictable result of secure, direct mobile communication.

Ground 2: Obviousness over Chieu, Ford, and Yoshida - Claim 2 is obvious over Chieu in view of Ford and further in view of Yoshida.

• Prior Art Relied Upon: Chieu (Patent 5,515,366), Ford (Patent 5,481,613), and Yoshida (Patent 5,949,764).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground built upon Ground 1 to address dependent claim 2, which added establishing direct communications with a third mobile station (i.e., a conference call). Petitioner argued Chieu suggested establishing "peer groups" of multiple portable units. Yoshida was introduced to explicitly teach methods for establishing conference calls among three or more mobile stations on a TDMA network, confirming this capability was well-known.
  • Motivation to Combine: A POSITA would have been motivated to add a known conference call capability (as taught by Yoshida) to the secure direct communication system of Chieu and Ford to increase its utility. Adding multi-party functionality to a communication system was a common and desirable design goal.
  • Expectation of Success: Integrating a known group calling feature into the system of Chieu would have been a straightforward task for a POSITA with a high expectation of success.

Ground 3: Anticipation by Ford - Claim 8 is anticipated by Ford.

• Prior Art Relied Upon: Ford (Patent 5,481,613).

• Core Argument for this Ground:

  • Prior Art Mapping: Petitioner asserted that independent claim 8 was not tied to a wireless handshaking protocol but recited only the general steps of a bare hybrid encryption scheme. Ford was argued to expressly teach every element of this claim. Specifically, Ford’s background section described a first device ("Party A") generating a symmetric key, encrypting it with a second device's ("Party B's") public key, and transmitting it to the second device, which then decrypts it with its private key to establish a shared symmetric key for subsequent secure communication.
  • Key Aspects: This ground argued that claim 8 was an unpatentable attempt to claim a fundamental encryption concept that had been a staple in the art for decades before the ’095 patent was filed.

• Additional Grounds: Petitioner asserted that claim 7 as issued was anticipated by Chieu (Ground 3) and, if corrected to include limitations added during prosecution, would be obvious over Chieu and Ford (Ground 4). Petitioner explained that key hybrid encryption limitations, which were added to overcome a rejection of the original claims over Chieu, were inadvertently omitted from the clean version of the issued claim 7, rendering it invalid on its face over the same prior art cited by the Examiner.

4. Key Claim Construction Positions

• "portion(s) of a radio frequency band": Petitioner proposed this term should be construed as "a 'circuit' or a portion of an RF channel characterized by time and frequency." This construction was based on the specification's description of a radio frequency band being divided into "conduits" (frequency) and further into "circuits" (frequency and time).
• "sub-portion" of an RF band: Petitioner proposed this term should be construed as "a 'slot' or a time-sliced portion of a circuit." This was based on the specification's teaching that each "circuit" is further divided into "slots" for carrying signaling and data, such as request and acknowledge signals.

5. Relief Requested

• Petitioner requested institution of an inter partes review and cancellation of claims 1-8 of the ’095 patent as unpatentable.