PTAB

IPR2022-00658

NXP USA Inc v. MediaTek Inc

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Wireless Communication System Using Dual Carrier Modulation
  • Brief Description: The ’948 patent discloses a wireless station for use in a wireless local area network. The system is designed to enhance transmission reliability by using dual carrier modulation (DCM) on encoded data, which is then mapped to frequency subcarriers of a resource unit (RU) using a specific low-density parity-check (LDPC) tone mapping scheme.

3. Grounds for Unpatentability

Ground 1: Obviousness over WiMedia - Claims 11-18 and 20 are obvious over WiMedia.

  • Prior Art Relied Upon: WiMedia (MultiBand OFDM Physical Layer Specification, WiMedia Alliance, Aug. 11, 2009).
  • Core Argument for this Ground: Petitioner argued that the WiMedia standard, a prior-art system for wireless personal area networks, discloses all elements of a wireless station as recited in the challenged claims. Petitioner contended that WiMedia teaches a complete system that performs encoding, DCM, tone mapping, and transmission in a manner that renders the claimed invention obvious.
    • Prior Art Mapping: Petitioner asserted that WiMedia discloses the limitations of independent claim 11. The WiMedia specification describes a wireless station with an encoder that can operate as an LDPC encoder for certain data rates. For the modulation limitation, WiMedia’s “QPSK or DCM Mapper” was identified as a modulator that, when DCM is applied, uses a four-dimensional constellation comprising two distinct 16-QAM constellations to generate a first and second set of modulated symbols from the same encoded bits. For tone mapping, Petitioner argued that WiMedia’s “OFDM Modulator” functions as the claimed tone mapper, mapping the first set of 50 modulated symbols to a first half of the 100 available data subcarriers (the RU) and the second set to the second half. Finally, WiMedia’s physical layer (PHY) specifications were shown to include a transmitter for sending the resulting RF signal to a destination station.
    • Key Aspects: A key technical point was that a person of ordinary skill in the art (POSITA) would understand the functional overlap in WiMedia's terminology, recognizing that its "DCM Mapper" performs modulation and its "OFDM Modulator" performs tone mapping, thereby meeting the distinct claim elements.

Ground 2: Obviousness over 802.11ac and WiMedia - Claims 11, 15, and 19 are obvious over 802.11ac, 802.11-2012, and WiMedia.

  • Prior Art Relied Upon: 802.11ac (IEEE Standard 802.11ac™-2013), 802.11-2012 (IEEE Standard 802.11™-2012), and WiMedia.

  • Core Argument for this Ground: Petitioner contended that the widely-used 802.11ac standard (in conjunction with its base, 802.11-2012) discloses a baseline wireless station with all the necessary components (encoder, modulator, tone mapper, transmitter) but lacking the claimed dual-modulation functionality. A POSITA would have been motivated to modify the 802.11ac system by incorporating the DCM technique taught in WiMedia to achieve known benefits of improved communication reliability and robustness.

    • Prior Art Mapping: The 802.11ac standard was shown to disclose a wireless station with an LDPC encoder, a constellation mapper (modulator), and an LDPC tone mapper. However, this standard modulator generates only a single set of modulated symbols. WiMedia was cited for its teaching of DCM, where two sets of modulated symbols are generated in parallel from the same input bits using two different modulation schemes. Petitioner argued for modifying the 802.11ac modulator to perform this dual modulation and modifying its tone mapper to map the resulting two sets of symbols onto first and second halves of the frequency subcarriers, as explicitly taught by WiMedia.
    • Motivation to Combine: A POSITA would combine the teachings to gain the well-understood advantages of DCM, including lower bit error rate (BER) and improved system reliability through frequency diversity and redundancy. The combination was presented as a straightforward application of a known technique (DCM from WiMedia) to a known system (802.11ac) to achieve a predictable improvement.
    • Expectation of Success: Success would have been expected because both standards are based on similar OFDM wireless communication principles. The required modifications, such as configuring the 802.11ac modulator to use a second 16-QAM constellation, were argued to be well within the skill of a POSITA.
    • Key Aspects: For claim 19, Petitioner argued it would have been obvious to use a different LDPC tone-mapping distance when DCM is applied. Applying DCM effectively halves the number of available subcarriers for each data stream. The 802.11ac standard itself teaches that a smaller channel bandwidth requires a smaller tone-mapping distance (DTM). Therefore, a POSITA would have recognized that applying DCM would necessitate reducing the DTM value compared to when DCM is not used, thus meeting the claim limitation.

  • Additional Grounds: Petitioner asserted an additional obviousness challenge for claims 11-18 and 20 over WiMedia in view of 802.11ac, arguing that to the extent WiMedia was found deficient in disclosing any component, 802.11ac provided the missing element as an obvious implementation choice.

4. Relief Requested

  • Petitioner requests institution of an inter partes review (IPR) and cancellation of claims 11-20 of Patent 10,211,948 as unpatentable.