PTAB

IPR2016-01208

Apple Inc v. Evolved Wireless LLC

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Method and Apparatus for Generating and Transmitting Code Sequence in a Wireless Communication System
  • Brief Description: The ’916 patent discloses methods for generating a code sequence for use in wireless communications, such as a Constant Amplitude Zero Auto-Correlation (CAZAC) sequence. The invention addresses generating a sequence of a desired length from a base sequence of a different length (e.g., a prime number length) by modifying it, which includes adding a padding portion via cyclic extension (prefix or postfix) and applying a circular shift to the resulting sequence.

3. Grounds for Unpatentability

Ground 1: Anticipation of Claims 1-3, 5-8, and 10 under §102 over [Zhuang327](https://ai-lab.exparte.com/case/ptab/IPR2016-01208/doc/1007)

  • Prior Art Relied Upon: Zhuang327 (Patent 7,599,327).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Zhuang327 discloses every element of the challenged claims. Zhuang327 describes a method for a subscriber station to access a wireless system by generating and transmitting an "access signal." This process involves selecting a base "GCL sequence" of a first length (NG), which is the largest prime number smaller than a desired length (K). An "access sequence" of the second, desired length (K) is then generated by a cyclic extension of the GCL sequence, specifically by copying initial terms of the GCL sequence and appending them to its end (a cyclic postfix). Zhuang327 further discloses performing a circular shift on the resulting time-domain access signal before transmission to create additional ranging opportunities. This process directly maps to the limitations of independent claims 1 and 6.
    • Key Aspects: This ground relies on Petitioner’s proposed claim construction that "acquiring... by a cyclic extension" is broad enough to encompass additional operations, such as the Inverse Fast Fourier Transform (IFFT) that Zhuang327 applies after the cyclic extension step.

Ground 2: Obviousness of Claims 4 and 9 under §103 over Zhuang327 in view of [Popovic](https://ai-lab.exparte.com/case/ptab/IPR2016-01208/doc/1009)

  • Prior Art Relied Upon: Zhuang327 (Patent 7,599,327) and Popovic ("Generalized chirp-like polyphase sequences with optimum correlation properties," IEEE Trans. On Information Theory, July 1992).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground addresses claims 4 and 9, which require the base code sequence to be a Zadoff-Chu (ZC) sequence. Petitioner contended that while Zhuang327 discloses using a Generalized Chirp-Like (GCL) sequence for its desirable correlation properties, Popovic explicitly teaches that ZC sequences are a well-known special case of GCL sequences. Popovic explains that ZC sequences exhibit the same optimal auto- and cross-correlation properties that motivated the use of GCL sequences in Zhuang327.
    • Motivation to Combine: A POSITA would combine these references because Popovic identifies ZC sequences as a computationally simpler alternative to the more general GCL sequences. A POSITA would have been motivated to substitute the GCL sequence in Zhuang327 with a ZC sequence to achieve the same desired performance (good correlation properties) while reducing computational load and power consumption, a significant advantage for mobile devices.
    • Expectation of Success: Success would be expected because Popovic establishes that ZC sequences are a subset of GCL sequences that retain all the relevant desirable properties for the application described in Zhuang327.

Ground 3: Obviousness of Claims 1-3, 5-8, and 10 under §103 over Zhuang327 in view of [Hou](https://ai-lab.exparte.com/case/ptab/IPR2016-01208/doc/1011)

  • Prior Art Relied Upon: Zhuang327 (Patent 7,599,327) and Hou (Patent 8,116,195).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground was presented as an alternative to Ground 1, addressing a potentially narrower claim construction where the circular shift is performed on the frequency-domain sequence before the IFFT, rather than on the time-domain sequence after. Zhuang327 teaches generating a frequency-domain access sequence and then applying a circular shift to the corresponding time-domain signal. Hou teaches techniques for generating preamble sequences based on CAZAC sequences, explicitly disclosing that cyclic shifts can be applied in either the frequency domain or the time domain to generate additional distinct sequences for synchronization and transmitter identification.
    • Motivation to Combine: A POSITA would combine the teachings to improve the system in Zhuang327. Hou’s technique of applying cyclic shifts directly to the frequency-domain sequence serves the same purpose as Zhuang327’s time-domain shift—to increase the number of available ranging codes. A POSITA would have been motivated to apply Hou's well-known technique to Zhuang327’s system as a predictable way to generate more preamble sequences, improving system capacity and performance.
    • Expectation of Success: A POSITA would have a reasonable expectation of success because applying a cyclic shift in the frequency domain is a known, alternative method for achieving the same result as a time-domain shift, and it was a simple design choice among a finite number of predictable solutions.
  • Additional Grounds: Petitioner asserted an additional obviousness challenge against claims 6-8 and 10 based on Zhuang327 alone (arguing it would be obvious to co-locate sequence generation functions in a single subscriber station device) and a combination of Zhuang327, Hou, and Popovic against claims 4 and 9.

4. Key Claim Construction Positions

  • "acquiring/generating a code sequence having a second length by a cyclic extension..." (claims 1 and 6): Petitioner argued this phrase should be given its broadest reasonable interpretation to encompass a process that includes performing a cyclic extension, rather than being limited to a process consisting only of cyclic extension. This construction is critical because the primary reference, Zhuang327, performs an IFFT after the cyclic extension to generate the final sequence.
  • "cyclic prefix" / "cyclic postfix" (claims 2, 3, 7, and 8): Petitioner argued "cyclic prefix" encompasses appending a portion from the end of a sequence to its beginning, while "cyclic postfix" encompasses appending a portion from the beginning of a sequence to its end. This aligns with the specific cyclic extension method disclosed in Zhuang327.

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-10 of the ’916 patent as unpatentable.