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`UNITED STATES PATENT AND TRADEMARK OFFICE
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`BEFORE THE PATENT TRIAL AND APPEAL BOARD
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`ERICSSON INC. and TELEFONAKTIEBOLAGET LM ERICSSON,
`Petitioners
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`v.
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`INTELLECTUAL VENTURES II LLC
`Patent Owner
`____________________
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`Case IPR2014-01185
`Patent 7,269,127
`____________________
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`PATENT OWNER RESPONSE
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`Mail Stop PATENT BOARD
`Patent Trial and Appeal Board
`U.S. Patent & Trademark Office
`P.O. Box 1450
`Alexandria, VA 22313-1450
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`I. 
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`II. 
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`IPR2014-01185
`U.S. Patent No. 7,269,127
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`Table of Contents
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`Introduction ...................................................................................................... 1 
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`The ’127 patent provides an innovative wireless transmitter .......................... 2 
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`A. 
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`The serious limitations of existing training designs—excessive
`training time reduced overall communication efficiency. .................... 2 
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`B. 
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`The ’127 patent provides an innovative training sequence design. ...... 5 
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`1. 
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`2. 
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`3. 
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`The encoder element. .................................................................. 7 
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`The modulator element. .............................................................. 7 
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`A frame structure embodiment from the ’127 patent. ................ 8 
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`III.  Claims 1–3 and 5 are patentable over the combination of Schmidl and
`Arslan [Ground 1]. ......................................................................................... 11 
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`A. 
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`The combination of Schmidl and Arslan does not disclose a
`“pilot/training symbol inserter configured to insert pilot symbols into
`data blocks” as required by independent claim 1. .............................. 11 
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`1. 
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`2. 
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`The broadest reasonable interpretation of the term “pilot
`symbol” is a “frequency domain symbol for refining the
`calibration of a receiver to a transmitter.” ................................ 12 
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`The system resulting from the combination of Schmidl and
`Arslan does not “insert pilot symbols into data blocks.” .......... 21 
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`B. 
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`The encoder of Schmidl and Arslan does not include the
`“pilot/training symbol inserter” element in claim 1. ........................... 27 
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`IV.  Dependent claims 4 and 6–10 are patentable over the combination of
`Schmidl, Arslan, and Kim [Ground 2]. ......................................................... 28 
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`V.  Dependent claim 17 is patentable over the combination of Schmidl, Arslan,
`Kim, and Heiskala [Ground 3]. ..................................................................... 28 
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`A. 
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`B. 
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`C. 
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`IPR2014-01185
`U.S. Patent No. 7,269,127
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`Petitioners’ proposed combination does not apply because the
`transmitter of claim 17 includes a single encoder coupled to two
`modulators and two antennas. ............................................................. 29 
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`Claim 17 is consistent with the transmitter disclosed in the
`specification of the ’127 patent. .......................................................... 31 
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`Claim 17, which has one encoder, is not rendered obvious by the
`combined transmission system of Heiskala and Schmidl, Arslan and
`Kim, which has two encoders operating in parallel. ........................... 32 
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`VI.  Conclusion ..................................................................................................... 35 
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`Statutes 
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`Table of Authorities
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`IPR2014-01185
`U.S. Patent No. 7,269,127
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`35 U.S.C. § 103 ........................................................................................................ 31
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`Regulations 
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`37 C.F.R. § 42.100(b) ................................................................................................ 9
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`37 C.F.R. §1.57(e) .................................................................................................... 29
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`Exhibit List
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`IPR2014-01185
`U.S. Patent No. 7,269,127
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`Exh. No.
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`IV 2001
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`Description
`Biography of Gordon Stüber (October 14, 2014),
`http://users.ece.gatech.edu/stuber/
`Biography of Dr. Apurva N. Mody (October 14, 2014),
`http://www.inatel.br/iwt2013/index.php/keynote-speakers-sp-
`212359168/dr-apurva-n-mody
`IV 2003 May 14, 2015 Official Deposition Transcript of Zygmunt J. Haas
`IV 2004 Webster’s II Dictionary
`IV 2005 Oxford Pocket American Dictionary of Current English
`IV 2006 Webster’s New World Dictionary
`IV 2007 Webster’s Ninth New Collegiate Dictionary
`IV 2008 Webster's II New Riverside University Dictionary
`IV 2009 Declaration of Dirk Hartogs, Ph.D.
`IV 2010
`Curriculum Vitae of Dirk Hartogs, Ph.D.
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`IV 2002
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`I.
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`Introduction
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`IPR2014-01185
`U.S. Patent No. 7,269,127
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`The Board should confirm the challenged claims as patentable over the
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`asserted references. The ’127 patent addressed an important issue related to
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`improving efficiency, and it did it in a novel way. Petitioners base their proposed
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`grounds that claims 1–10 and 17 of the ’127 patent are unpatentable on
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`unreasonable interpretations of certain claim terms and their unjustified reliance on
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`various combinations of Schmidl, Arslan, Kim, and Heiskala. Applying proper
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`claim interpretations, the proposed combinations fail to teach structural elements of
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`the claims. And when the references are correctly understood, the instituted
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`grounds fail for two reasons. First, the combination of Schmidl and Arslan does not
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`teach the pilot/training symbol inserter recited in claim 1, based on a proper
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`interpretation of the term “pilot symbol” and a correct reading of Arslan. Second,
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`the combination of Schmidl, Arslan, Kim, and Heiskala does not reach the
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`transmitter of claim 17, which recites a single encoder, because the combination
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`necessarily requires multiple encoders.
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`Patent Owner’s common sense positions are fully supported by its expert,
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`Dr. Dirk Hartogs, who has extensive experience with wireless systems. Dr. Hartogs
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`was an early pioneer of OFDM, which is the basis of not only the ’127 patent but
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`most broadband wireless standards. (Hartogs Decl., ¶ 8) Dr. Hartogs’s expertise in
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`IPR2014-01185
`U.S. Patent No. 7,269,127
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`synchronization of OFDM systems supports Patent Owner’s position that the
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`challenged claims of the ’127 patent are patentable over the art of record. But
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`Petitioners’ expert, Dr. Haas, also supports Patent Owner’s positions.
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`II. The ’127 patent provides an innovative wireless transmitter
`Wireless communication systems use training sequences to both synchronize
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`a receiver to a transmitter and estimate channel parameters. Training designs at the
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`time of invention were inefficient, especially when applied to multiple-antenna
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`systems. The ’127 patent combines a novel training sequence design with
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`frequency-domain pilots that refine calibration to produce a more efficient, low-
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`overhead design that scales favorably with multiple antennas.
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`A. The serious limitations of existing training designs—excessive
`training time reduced overall communication efficiency.
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`Wireless transmitters often send “training sequences” before transmitting
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`data. (Hartogs Decl., ¶ 24.) Because the receiver knows these training sequences, it
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`can search for their presence in the received signal. Based on the location of the
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`training signals, the receiver can estimate distortion caused by frequency offset,
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`timing offset, electromagnetic propagation, or other transmission impairments
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`between the transmitter and receiver. (Hartogs Decl., ¶ 24.) In this way, the
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`receiver can account for unexpected distortion. (Hartogs Decl., ¶ 24.)
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`IPR2014-01185
`U.S. Patent No. 7,269,127
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`Orthogonal frequency division multiplexing (OFDM) training systems map
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`binary information to complex symbols, encoding the information into the
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`amplitude or phase (or both) of multiple carriers of a transmitted signal. A certain
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`number of bits are represented by a complex symbol, which is a complex number
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`that is sometimes referred to as a sample. (Hartogs Decl., ¶ 21.) OFDM systems
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`transmit these complex symbols on orthogonal frequency-domain carriers, whereas
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`conventional single-carrier systems transmit the complex symbols sequentially in
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`the time domain.
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`OFDM systems replicate the effect of using multiple, costly oscillators by
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`using an inverse discrete Fourier transform (IDFT). A number of complex
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`frequency-domain symbols are transformed, by the IDFT, to block samples. Each
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`of these block samples carries information about each of frequency-domain
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`symbols. This signal structure allows broadband transmission and reception with
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`low computational complexity relative to conventional single-carrier signals.
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`(Hartogs Decl., ¶ 21.) An OFDM symbol is a collection of block samples, together
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`with a cyclic prefix, which may simply be a copy of the last several samples of the
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`block prepended to its beginning. (See, e.g., ’127 patent, 7:51–8:18 and FIG. 3.)
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`OFDM transmitters therefore transmit a number of frequency-domain
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`complex symbols as modulated carriers. OFDM training requirements differ from
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`IPR2014-01185
`U.S. Patent No. 7,269,127
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`conventional modulations because this frequency domain aspect is more sensitive
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`to frequency offset than conventional digital systems. (Hartogs Decl., ¶ 25.)
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`Before the claimed invention of the ’127 patent, overall efficiency of OFDM
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`systems was limited because excessive transmission time was required for training.
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`This excess largely stemmed from the use of different training sequences for
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`different purposes. (Hartogs Decl., ¶24.) For example, the ’127 patent states that
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`“the IEEE Standard 802.11a preamble structure includes a short sequence, which
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`provides time synchronization and coarse frequency offset estimation, followed by
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`a long sequence, which provides fine frequency and channel estimation.” (’127
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`patent, 3:1–5.) The newly developed multiple-input multiple-output (MIMO)
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`communication comprising “signals [] typically transmitted over a common path…
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`by multiple antennas” exacerbated the inefficiencies of these existing sequences.
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`(Id. at 1:54–56.) Prior art solutions to this problem were limited.
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`Gordon Stuber, Professor of Electrical Engineering at Georgia Tech
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`University, and his graduate student Apurva N. Mody, recognized the limitations
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`of existing training designs and set out to solve those problems. Prof. Stuber is a
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`well-known expert in the field and has received several awards “for his
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`contributions to theoretical research in wireless communications.” (See Ex. 2001.)
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`Dr. Mody is also an industry leader serving as Chairman of the IEEE 802.22
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`IPR2014-01185
`U.S. Patent No. 7,269,127
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`Working Group on Wireless Regional Access Networks as well as Chairman of the
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`Whitespace Alliance. (See Ex. 2002.) Their collaboration produced “an efficient
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`preamble structure for use in wireless communication systems [that] provide[s]
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`both synchronization and parameter estimation.” (’127 patent, 2:60–62.)
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`The ’127 patent provides an innovative training sequence design.
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`B.
`In contrast to the prior art, the ’127 patent discloses a transmitter with a
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`single encoder coupled to potentially multiple modulators and multiple antennas.
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`The annotated figure below illustrates such a transmitter, with an encoder that
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`“encodes data… from a data source” (id. at 5:13–15) and “one or more
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`modulators… to modulate signals for transmission over the [wireless] channel” (id.
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`at 5:32–34). This figure combines FIGS. 1–3 of the ’127 patent.
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`IPR2014-01185
`U.S. Patent No. 7,269,127
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`HARTOGS FIG. A
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`The encoder is distinguished from the prior art because its structure includes
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`a pilot/training symbol inserter which inserts pilots in the frequency domain and
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`produces an enhanced training sequence. Unlike the art of record, the ’127 patent
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`couples a single encoder to a plurality of modulators. (See, e.g., claim 17.) The
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`following sections provide detail on the encoder, modulator, and overall frame
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`structure disclosed in the ’127 patent.
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`IPR2014-01185
`U.S. Patent No. 7,269,127
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` The encoder element.
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`1.
`The disclosed transmitter’s encoder 18 includes a channel encoder 36 that
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`“adds parity to the signals so that the decoder [] can detect errors in the received
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`channel encoded signals, which may occur… due to environmental conditions that
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`affect the channel.” (Id. at 6:46–50.) The encoder also includes a symbol mapper
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`38 that “map[s] channel encoded signals into data blocks.” (Id. at 6:55–56.) In this
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`context, the ’127 patent uses the term “symbol” to refer to elements from an
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`alphabet such as binary phase shift keying (BPSK) or quadrature phase shift
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`keying (QPSK), which are modulated on the OFDM subcarriers. (See, e.g., id. at
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`6:59-65.)
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`If the encoder is part of a MIMO system, it may include a space-time
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`processor 40, which “encode[s] a stream of data blocks, received from the symbol
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`mapper 38, through space-time processing.” (Id. at 7:3–4.) The encoder also
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`includes a pilot/training symbol inserter 46 that “typically provides pilot blocks
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`and training blocks that are inserted into (or combined with) the data blocks.” (Id.
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`at 7:23–25.) The operation of the pilot/training symbol inserter is discussed in
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`relation to FIG. 6 in subsection 3.
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`2. The modulator element.
`The disclosed transmitter’s modulator contains a “serial-to-parallel converter
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`50 [that] converts the training blocks and data blocks from a serial format to a
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`IPR2014-01185
`U.S. Patent No. 7,269,127
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`parallel format for further processing by other components.” (Id. at 7:59–62.) The
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`IDFT stage 52 “converts these blocks from the frequency domain to the time
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`domain.” (Id. at 8:4–5.) For a data block, the IDFT stage converts N frequency
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`domain samples into N time domain samples using an N-point IDFT. (See id. at
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`8:6–11.) The cyclic prefix inserter 54 then “inserts an additional number of
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`samples ‘G’ with each data block and training block to form data symbols and
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`training symbols.” (Id. at 8:13–15.) The modulator then converts the samples from
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`parallel to serial, converts the digital samples to analog, and uses a mixer to up-
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`convert the analog signal to RF so that it may be amplified and transmitted. (See id.
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`at 8:19–34.)
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`3. A frame structure embodiment from the ’127 patent.
`FIG. 6, reproduced in annotated form below, illustrates an exemplary frame
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`structure. Focusing on Antenna Q, the frame structure 68 “includes a preamble
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`structure 70 and a data structure 72.” (Id. at 10:58–59.) “The preamble structure 70
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`typically includes one or more training symbols 74” (id. at 10:62–63) and “an
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`enhanced training symbol 79, located at the beginning of the preamble structure.”
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`(Id. at 11:3–5.) The training symbol 74 “includes a cyclic prefix 76 of length G and
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`a training block 78 of length NI… [and] has a length of G+NI samples in the time
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`domain.” (Id. at 10:65 to 11:2.) Therefore, a “symbol” in the context of a training
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`symbol
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`denotes a section of f samples inncluding a
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`IPPR2014-011185
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`UU.S. Patent
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`No. 7,2699,127
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`cyclic preefix and thee time dommain
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`output oof the IDFTT stage.
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`HARTTGOS FIGG. B
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`TThe data strructure 72 “includes one or morre data symmbols 80…… [which eeach]
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`includess a cyclic pprefix 76 aand a data bblock 82.”
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`(Id. at 11:
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`28–30.) A
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`the ’1277 patent, “ppilot symbols may also be interrmittently iinserted innto the dataa
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`symbolss 80 by thee pilot/trainning symbool inserter
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`46.” (Id. aat 11:45–477.) FIGS. 22
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`and 3 illustrate thaat the pilott symbols aare “inserteed periodiccally into tthe data
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`blocks”” (id. at 7:228) in the frrequency ddomain.
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`both trainiing symbools and piloot
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`symbolss. Howeveer, “[t]he teerm traininng blocks rrefers to onne or moree continuouus
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`sectionss of symbools provided by the piilot/traininng symbol iinserter 466” (id. at 7:
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`32 (empphasis addeed)), whereeas pilot syymbols “aare insertedd periodicaally into thee
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`IPPR2014-011185
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`UU.S. Patent
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`No. 7,2699,127
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`data bloocks.” (Id. at 7:28.) FFurthermore, “[t]rainiing blocks
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`are preferaably insertted
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`into preeamble struuctures at thhe beginniing of the fframe strucctures and
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`once peer frame strructure.” (IId. at 7:32––34.)
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`AAs noted abbove, “the preamble sstructure 770 containss one symbbol referredd
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`to… as an enhanced trainingg symbol 779, located
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`structurre 70.” (Id. at 11:2–5..) The trainning block
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`78 of the eenhanced ttraining
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`symbol 79 is dividded into seeveral
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`sectionss” (id. at 11:5–6) thatt are
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`used forr various ppurposes. FFor
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`FIG. 7, reproduced below, iss
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`throughh 86-5) andd the cyclicc prefix 76
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`trainingg symbol 844. (See id. at 13:32–338.) These
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`combined into varrious intervvals that arre used for r different ppurposes. FFor exampple,
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`“[a] firsst interval 888 of the enhanced trraining symmbol 84 sppans the fir
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`86-1, 866-2…[and is used forr] time synnchronizati
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`on and coaarse frequeency offsett
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`estimatiion.” (Id. aat 13:50–544.) A seconnd intervall 90, whichh includes ssections 866-3
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`IPR2014-01185
`U.S. Patent No. 7,269,127
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`and 86-4, does not overlap with the first interval 88 and “includes sequences for
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`providing parameter estimation, such as channel estimation and noise variance
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`estimation.” (Id. at 13:59–60.) A third interval 92 overlaps with the first and
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`second intervals and “provides sequences for fine frequency offset estimation.” (Id.
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`at 13:63–64.) FIGS. 8 and 9 provide alternative embodiments of the enhanced
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`training symbol with various sections, intervals, and antennas.
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`III. Claims 1–3 and 5 are patentable over the combination of Schmidl and
`Arslan [Ground 1].
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`The combination of Schmidl and Arslan does not disclose every feature of
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`claims 1–3 and 5, and accordingly these claims are patentable over these
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`references. Specifically, the combined prior art references do not disclose the
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`“claimed pilot training symbol inserter.” Further, what Petitioners argue is a “pilot
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`symbol” is not a pilot symbol and is not inserted into data blocks, as required in the
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`claim, and finally, the encoder disclosed in the asserted prior art does not include
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`the “pilot/training symbol inserter.”
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`A. The combination of Schmidl and Arslan does not disclose a
`“pilot/training symbol inserter configured to insert pilot symbols
`into data blocks” as required by independent claim 1.
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`To establish that the combination of Schmidl and Arslan does not disclose
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`the limitations of claim 1, Patent Owner first addresses the proper interpretation of
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`IPR2014-01185
`U.S. Patent No. 7,269,127
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`the term “pilot symbol.” In the next subsection, Patent Owner shows that Schmidl
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`and Arslan are not invalidating prior art.
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`1. The broadest reasonable interpretation of the term “pilot
`symbol” is a “frequency domain symbol for refining the
`calibration of a receiver to a transmitter.”
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`The broadest reasonable interpretation of the term “pilot symbol,” in the
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`context of the ’127 patent, is a “frequency domain symbol for refining the
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`calibration of a receiver to a transmitter.” The broadest reasonable interpretation
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`for the term “pilot symbol” is important to determining whether the independent
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`claim 1 and dependent claims 2, 3, and 5 are patentable over the combination of
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`Schmidl and Arslan. The next subsection shows that Arslan’s pilot portions are not
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`frequency domain symbols and thus not pilot symbols as described in the ’127
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`patent.
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`The Board found “for purposes of this [Institution] Decision that the
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`broadest reasonable construction” for the term pilot symbol “is apparent from the
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`context of the claims and specification.” (Institution Decision, p. 8.) Patent Owner
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`agrees with the Board that the claims and the specification dictate the basis for the
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`broadest reasonable interpretation in this case, and properly applied, that
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`interpretation coincides with Patent Owner’s. The word “symbol” is a term of art
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`that describes several different concepts in the field of communications. (Hartogs
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`IPR2014-01185
`U.S. Patent No. 7,269,127
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`Decl., ¶ 37.) (See also Haas Depn., 52:22 to 53:8.) Petitioners’ expert, Dr. Haas,
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`agrees, testifying at deposition that the term “symbol” “can have very different
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`meanings in different contexts. It’s— it’s a term which is used to signify different
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`things in different contexts.” (Haas Depn., 53:3–8)
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`a) The ’127 patent’s “pilot symbol” is a frequency domain
`symbol.
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`A “symbol” may be a frequency domain symbol or a time domain symbol,
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`“depending on which point in the whole process the particular use is—applies,” as
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`explained by Petitioners’ expert, Dr. Haas, during his deposition. (Haas Depn.,
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`76:2–3.) Patent Owner’s expert, Dr. Hartogs, agrees with Dr. Haas. In the context
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`of the ’127 patent, the designation of a “symbol” as a frequency domain symbol or
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`time domain symbol depends on the point of the transmission or reception process
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`where the symbol is being used. (Hartogs Dec., ¶ 38.) In the ’127 patent, the “pilot
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`symbol” inserted into a data block by the encoder of the transmitter is a frequency
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`domain symbol.
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`FIG. C of the Hartogs Declaration, which illustrates a transmitter 14 that
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`incorporates the encoder 18 of FIG. 2 and a modulator 24 of FIG. 3, shows that the
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`“pilot symbol” is a frequency domain symbol. The encoder 18 includes a “symbol
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`mapper 38, which receives channel encoded signals from the channel encoder 36.”
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`(’127 patent, 6:52–54.) “The symbol mapper 38 is typically configured to map
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`IPR2014-01185
`U.S. Patent No. 7,269,127
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`channel encoded signals into data blocks.” (’127 patent, 6:54–56.) A data block
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`includes one or more samples. (Hartogs Decl., ¶ 39.) The space-time processor 40
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`of the encoder 18 “is typically configured to encode a stream of data blocks,
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`received from the symbol mapper 38, through space-time processing to form the
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`data block designated for different TDBs [transmit diversity branches] 22.” (’127
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`patent, 7:2–5.)
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`The encoder 18 also includes a pilot/training symbol inserter 46 that
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`provides pilot blocks (symbols)1 “which are inserted periodically into the data
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`blocks.” (’127 patent, 7:26–28.) “Typically, pilot symbols may be inserted at any
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`point in the data blocks.” (’127 patent, 7:28–30.)
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`1 The ’127 Patent states: “The term pilot blocks, as used in this description,
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`refers to symbols provided by the pilot/training symbol inserter 46….” (’127
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`patent, 7:26–27.)
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`IPR2014-01185
`U.S. Patent No. 7,269,127
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`HARTOGS FIG. C: Transmitter of the ’127 patent
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`The pilot symbols are frequency domain symbols inserted into a data block
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`in the frequency domain. (Hartogs Decl., ¶ 41.) The data blocks (having the
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`inserted pilot symbols) are provided to the IDFT stage 52 of the modulator 24. The
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`IDFT stage 52 “converts the samples in the frequency domain to N samples for
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`each data block…in the time domain.” (’127 patent, 8:6–11.) Petitioners’ expert
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`agrees that everything to the left of IDFT stage 52 of the modulator 24 is in the
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`frequency domain:
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`So I believe that the ’127 patent uses the OFDM symbol, the
`term “OFDM symbol” or symbol differently depending on
`which point in the whole process the particular use is -- applies.
`So if… we take Figure—Figure 1,… Figure 3 would be better.
`You have the IDTF [sic]. The IDTF, which is the inverse
`discrete Fourier transform, to the left of this, which is what
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`IPR2014-01185
`U.S. Patent No. 7,269,127
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`I am going to refer as frequency domain that’s—and to the
`right of the IDTF is—is what I’m going to refer as time domain.
`In the frequency domain, the OFDM symbol is—corresponds to
`what the patent refers to as block, as a data block or training
`symbol block. To the right of the IDTF symbol—sorry, to the
`right of the IDTF box, the patent refers to symbol as being the
`combination of the block plus the guard. So in time domain, a
`symbol would be block plus guard. In the frequency domain,
`there’s no guard in frequency domain, so it will be only the
`block. When I refer to guard, I just want to remind ourselves
`that I’m talking about cyclic prefix.
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`(Haas Depn., 75:25 to 76:23 (emphasis added).) Dr. Hartogs’s testimony shows
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`there is no dispute that pilot symbols are frequency domain symbols inserted into
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`data blocks in the frequency domain. (Hartogs Decl., ¶ 41.)
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`Dr. Hartogs further illustrates the high-level process performed by the
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`transmitter in FIG. D, reproduced below. FIG. D depicts a data block having four
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`samples, after processing by space-time processor 40. (Hartogs Decl., ¶ 42.) The
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`pilot/training inserter 46 of the encoder inserts pilot symbols into the data block—
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`in this case alternating pilot symbol samples between data block samples. (Hartogs
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`Decl., ¶ 42.) As Patent Owner has explained, because this process occurs before
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`the IDFT, the pilot symbols must be frequency domain symbols, and the insertion
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`process occurs in the frequency domain. (Hartogs Decl., ¶ 42.)
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`IPR2014-01185
`U.S. Patent No. 7,269,127
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`HARTOGS FIG. D
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`The IDFT stage 52 of the modulator converts the data block with pilot
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`symbols from the frequency domain into a time domain data block. (Hartogs Decl.,
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`¶ 43.) At this point, the cyclic prefix inserter of the modulator appends a cyclic
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`prefix to the time domain data block creating a data symbol. (Hartogs Decl., ¶ 43.)
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`The data symbol, having a cyclic prefix, is a time domain symbol. (Hartogs Decl.,
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`¶ 43.) (See also Haas Depn., 81:2–12.)
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`b) A “pilot symbol” refines “the calibration of a receiver to a
`transmitter.”
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`A “pilot symbol” is known to both the transmitter and receiver and is
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`“transmitted with data blocks to calibrate (i.e., synchronize) the receiver 16 to the
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`IPR2014-01185
`U.S. Patent No. 7,269,127
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`transmitter 14 on a small scale.” (’127 patent, 7:40–42.) Both Petitioners’ and
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`Patent Owner’s experts agree that the “pilot symbol” refines the calibration that
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`exists between a transmitter and receiver:
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`Q. Okay. And what’s the difference between synchronization
`that’s performed using the preamble and synchronization
`that’s performed using a pilot?
`A. Typically, and again I emphasize typically, the training
`sequences are used to provide initial synchronization and the
`pilots are typically used to provide to resynchronize the
`transmissions.
`Q. Okay. And is that the way the training symbols and pilot
`symbols are being used in the ’127 patent?
`A. I believe that this is the way that the training symbols and
`pilot symbols are used in the ’127 patent.
`Q. Okay. And you used the term “initial synchronization.” What
`do you mean by initial synchronization?
`A. Well, if you send a frame and this is the only thing that you
`send, then at the beginning of the frame, there’s presumably
`no synchronization between the transmitter and the receiver.
`The training sequence, or the training symbol more precisely,
`the training symbol will provide the initial synchronization.
`As the frame goes on, so to speak, the channel will change,
`and the synchronization may be -- may be -- may need to
`be adjusted or recalibrated, so to speak, and that’s where
`the pilot symbols will help with.
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`IPR2014-01185
`U.S. Patent No. 7,269,127
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`(Haas Depn., 57:11 to 68:13 (emphasis added); see also Hartogs Decl., ¶ 44)
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`c) The Board should reject Petitioners’ proposed construction.
`The Petitioners proposed construing the term “pilot symbol” as “a symbol
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`located in the data structure and used for performing synchronization.” (Petition, p.
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`23.) The Board should reject that proposed construction because it is overly broad
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`and does not take into account the context of the term in the ’127 patent, which
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`Petitioners’ own expert views as critical in construing claim terms. (See Haas
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`Depn., 1-5:17 to 106:12.)
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`First, Petitioners’ overly-broad construction does not distinguish between the
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`different and rather distinct “symbols” described in the ’127 patent, including a
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`pilot symbol, a training symbol, and a data symbol. Training symbols and data
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`symbols are time domain symbols because both are formed after the IDFT by
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`“insert[ing] an additional number of samples ‘G’ [a cyclic prefix] with each data
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`and training block.” (’127 patent, 8:13–14; see Hartogs Decl., ¶ 46; see also Haas
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`Depn., 76:18 to 77:17.) In contrast, as discussed above, pilot symbols are
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`frequency domain samples because they are placed within data blocks in the
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`frequency domain. (Hartogs Decl., ¶ 46.)
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`FIG. E from Hartogs Declaration (reproduced below) illustrate how a “pilot
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`symbol” comprises samples in the frequency domain while a “training symbol” and
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`IPPR2014-011185
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`UU.S. Patent
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`No. 7,2699,127
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`symbol” aare both commprised off a cyclic pprefix and aa number oof time dommain
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`a “data
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`sampless highlighting data bllocks and ttraining bloocks in botth the frequuency and
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`mains.
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`HARTTOGS FIGG. E
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`SSecond, Pettitioners’ bbroad conteention that t a “pilot syymbol” is aa symbol
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`“used foor performming synchrronization”” fails to diistinguish bbetween a
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`preamble
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`trainingg symbol, wwhich is ussed for coaarse calibraation (synchhronizationn), and a ppilot
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`symbol,, which is uused to reffine the callibration beetween a reeceiver andd transmittter.
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`(Hartoggs Decl., ¶ 447.) Although traininng symbolss also are ““used to peeriodically
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`calibrate the receivver 16 to thhe transmiitter 14” (’
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`127 patentt, 7:44–45)), they provvide
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`such callibration on a large s
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`cale by occcupying thhe entire baandwidth ssuch that
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`IPR2014-01185
`U.S. Patent No. 7,269,127
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`“training symbols may be unique for each sub-channel.” (’127 patent, 7:46.) Pilot
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`symbols are not placed on every sub-channel, but instead are “intermittently
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`inserted into the data symbols” (’127 patent, 11:45–46) to refine the calibration.
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`Based on the foregoing, the Board should reject Petitioners’ overly-broad
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`proposed construction and adopt Patent Owner’s reasonable construction.
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`2. The system resulting from the combination of Schmidl and
`Arslan does not “insert pilot symbols into data blocks.”
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`Petitioners acknowledge that Schmidl fails to disclose “an encoder having a
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`pilot/training symbol inserter… configured to insert pilot symbols into data
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`blocks.” (Petition, pp. 28–30.) Recognizing that this disclosure failure undercuts its
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`obviousness argument, Petitioners contend that, nevertheless, the pilot portions of
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`Arslan meet this element of claim 1. (Petition, p. 29.) However, Petitioners’
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`argument fails because the pilot portions of Arslan differ from the recited “pilot
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`symbols” of the ’127 patent. First, Arslan’s pilot portions are time-domain
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`symbols, whereas the pilot symbols of the ’127 patent are frequency domain
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`symbols. Second, Arslan’s pilot portions are inserted between data blocks and not
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`into data blocks, as required by the claim 1.
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`a) Arslan’s pilot portions are not frequency domain symbols, as
`required by claim 1.
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`In section III.A.1, Patent Owner showed that the broadest reasonable
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`interpretation of the t