.
`
`41001
`U.S.APPLICA O N
`0 9 )1 b 7‘5273
`
`,
`
`FR 1.5)
`
`INTERNATIONAL APPLICATION NO.
`PCT/EP98/02184
`TITLE OF INVENTION
`Method and Apparatus for Fine Freuenc S nchronization in Multi-Carrier Demodulation S stems
`APPLICANT(S) FOR DO/EO/US
`Ernst Eberlein, Sabah Badri, Stefan Li- , Stehan Buchholz, Albert Heubercer, Heinz Gerhaeuser
`
`INTERNATIONAL FILING DATE
`14 April 1998
`
`PRIORITY DATE CLAIMED
`
`Applicant herewith submits to the United States Designated/Elected Ofl'lce (DO/EO/US) the following items and other information:
`1.
`This is a FIRST submission of items concerning a filing under 35 U.S.C. 371.
`2. [:I This is a SECOND or SUBSEQUENT submission of items concerning a filing under 35 U.S.C. 371.
`3. D This express request to begin national examination procedures (35 U.S.C. 371(1)) at any time rather than delay
`examination until the expiration of the applicable time limit set in 35 U.S.C. 371(b) and PCT Articles 22 and 39(1).
`A proper Demand for International Preliminary Examination was made by the 19th month from the earliest claimed priority date.
`
`4.
`
`5.
`
`A copy of the International Application as filed (35 U.S.C. 371(c)(2))
`a.
`is transmitted herewith (required only if not transmitted by the International Bureau).
`
`has been transmitted by the International Bureau.
`b.
`c. D is not required, as the application was filed in the United States Receiving Office (RO/US).
`o. I] A translation ofthe International Application into English (35 U.S.C. 371(c)(2)).
`7.
`Amendments to the claims ofthe International Application under PCT Article 19 (35 U.S.C. 371(c)(3))
`a. D are transmitted herewith (required only if not transmitted by the International Bureau).
`b. E] have been transmitted by the International Bureau.
`c. D have not been made; however, the time limit for making such amendments has NOT expired.
`
`a!
`
`h
`
`
`:
`2:
`
`d,
`have not been made and will not be made.
`, 8. D A translation ofthe amendments to the claims under PCT Article 19 (35 U.S.C. 371(c)(3)).
`.
`9- El An oath or declaration ofthe inventor(s) (35 U.S.C. 371(c)(4)).
`
`10- D A translation ofthe annexes to the International Preliminary Examination Report under PCT Article 36
`(35 U.S.C. 371(c)(5)).
`
`Items 11. to 16. below concern document(s) or information included:
`11. El An Information Disclosure Statement under 37 CFR 1.97 and 1.98.
`
` “
`
`12. D An assignment document for recording. A separate cover sheet in compliance with 37 CFR 3.28 and 3.31 is included.
`
`13:
`
`A FIRST preliminary amendment.
`D A SECOND or SUBSEQUENT preliminary amendment.
`
`14.
`
`A substitute specification.
`
`15. D A change of power Of attorney and/or address letter.
`
`16»
`
`Other items or information:
`
`(a) Copy of International Application as filed (14 April 1998).
`(b) Copv of International Search Report (12 January 1999).
`(c) Copy of Published International Application (21 October 1999).
`(d) Copy of International Preliminary Examination Report (19 July 2000).
`
`page 1 of2
`
`Petitioner Sirius XM Radio Inc. - EX. 1005, p. 1
`
`.
`.
`,
`'532 Reed Poi/Pr:
`
`
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`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 1
`
`

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`T
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`‘v "
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`.S.APPLIC4.TIONNO (ificnown, see 37 CFRIS)
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`no
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`ATTORNEYS DOCKET NUMBER
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`I m
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`41001
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`cUL
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`eta.-
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`INTERNATIONAL ApleEjA'fioNNo
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`I '
`V
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`= .
`I
`PCT/EP98/021 84
`
`
`.
`.
`
`-
`..
`'
`17.
`The followmg fees are submitted:
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`International preliminary examination fee paid to USPTO (37 CFR 1.482)
`but all claims did not satisfy provisions of PCT Article 33(1)-(4) ........... $690.00
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`International preliminary examination fee paid to USPTO (37 CFR 1.482)
`and all claims satisfied provisions of PCT Article 33(1)—(4) ................ $100.00
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`SENDALLCORRESPONDENCETO:
`
`Roylance, Abrams, Berdo & Goodman, L.L.P.
`
`1300 19th Street, NW, Suite 600
`Washington, DC 20036
`
`M 6/7. Oéé11,:
`
`SIGNATURE
`
`John E. Holmes
`NAME
`29 ,392
`REGISTRATION NUIVIBER
`
`
`
`
`
`
`
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`
`Form PTO-1390 (REV 1001-00) page 2 of2
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 2
`\
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 2
`
`

`

`
`
`
`41001
`
`PATENT
`
`IN THE UNITED STATES PATENT AND TRADEMARK OFFICE
`
`In re Application of:
`
`Ernst Eberlein et al.
`
`Serial No.: Not Assigned
`Filed: Herewith
`
`Group Art Unit:
`
`Examiner:
`
`.
`
`For: Method and Apparatus for Fine Frequency
`Synchronization in Multi—Carrier Demodulation
`Systems
`
`PRELIMINARY AMENDMENT
`
`Assistant Commissioner for Patents
`
`Washington, DC. 20231
`
`Sir:
`
`This Preliminary Amendment is being filed concurrently with the US. national
`
`stage entry under 35 U.S.C. § 371 of International Application No. PCT/EP98/02184,
`
`which has an International Filing Date of April 14, 1998. Prior to examination and
`
`calculation of the filing fees, please amend the national stage application as follows:
`
`IN THE SPECIFICATION:
`
`Please delete the current specification comprising pages 1—40 and 48 (as amended in
`
`the International Preliminary Examination Report dated July 19, 2000) and replace it with
`
`the accompanying substitute specification.
`
`IN THE CLAIMS:
`
`Please cancel claims 1-18 annexed to the International Preliminary Examination
`
`Report dated July 19, 2000, and substitute the following new claims 19-34:
`
`19.
`
`A method of performing a fine frequency synchronization compensating for a
`
`carrier
`
`frequency deviation from an oscillator
`
`frequency in a multi—carrier
`
`demodulation system of the type capable of carrying out a differential phase
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 3
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 3
`
`

`

`decoding of multi-carrier modulated signals, said signals comprising a plurality of
`
`symbols, each symbol being defined by phase differences between simultaneous
`
`carriers having different frequencies, said method comprising the steps of:
`
`a)
`
`determining a phase difference between phases of the same carrier in
`
`different symbols;
`
`b)
`
`determining a frequency offset by eliminating phase shift uncertainties
`
`related to the transmitted information from said phase difference making use
`
`of a M—PSK decision device; and
`
`c)
`
`performing a feedback correction of said carrier frequency deviation based
`
`on said determined frequency offset.
`
` carriers having different frequencies, said method comprising the steps of:
`
`20.
`
`A method of performing a fine frequency synchronization compensating for a
`
`carrier
`
`frequency deviation from an oscillator
`
`frequency in a multi-carrier
`
`demodulation system of the type capable of carrying out a differential phase
`
`decoding of multi-carrier modulated signals, said signals comprising a plurality of
`
`symbols, each symbol being defined by phase differences between simultaneous
`
`at)
`
`b)
`
`determining respective phase of the same carrier in different symbols;
`
`eliminating phase shift uncertainties related to the transmitted information
`
`from said phases to determine respective phase deviations making use of a M-
`
`PSK decision device;
`
`c)
`
`determining a frequency offset by determining a phase difference between
`
`said phase deviations; and
`
`d)
`
`performing a feedback correction of said carrier frequency deviation based
`
`on said determined frequency offset.
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 4
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 4
`
`

`

`21.
`
`The method according to claim 19, wherein
`
`said steps a) and b) are performed for a plurality of carriers in said symbols,
`
`an averaged frequency offset is determined by averaging said determined frequency
`
`offsets of said plurality of carriers, and
`
`said feedback correction of said frequency deviation is performed based on said
`
`averaged frequency offset in said step c).
`
`
`
`
`
`
`
`22.
`
`The method according to claim 20, wherein
`
`said steps a), b) and c) are performed for a plurality of carriers in said symbols,
`
`an averaged frequency offset is determined by averaging said determined frequency
`
`offsets of said plurality of carriers, and
`
`said feedback correction of said frequency deviation is performed based on said
`
`averaged frequency offset.
`
`23.
`
`The method according to claim 19, wherein said step a) comprises the step of
`
`determining a phase difference between phases of the same carrier in symbols which
`
`are adjacent in the time axis direction.
`
`24.
`
`The method according to claim 19, wherein said step b) comprises the step of
`
`eliminating phase shift uncertainties corresponding to M-ary phase shifts.
`
`25.
`
`The method according to claim 20, wherein said step a) comprises the step of
`
`determining respective phases of the same carrier in symbols which are adjacent in
`
`the time axis direction.
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 5
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 5
`
`

`

`26.
`
`The method according to claim 20, wherein said step b) comprises the step of
`
`eliminating M—ary phase shifts.
`
`27.
`
`An apparatus for performing a fine frequency synchronization compensating for a
`carrier frequency deviation from an oscillator frequency,
`for a multi-carrier
`
`demodulation system of the type capable of carrying out a differential phase
`decoding of multi—carrier modulated signals, said signals comprising a plurality of
`symbols, each symbol being defined by phase differences between simultaneous
`
`carriers having different frequencies, said apparatus comprising:
`
`
` 28.
`
`means for determining a phase difference between phases of the same carrier in
`
`different symbols;
`
`M—PSK decision device for determining a frequency offset by eliminating phase shift
`
`uncertainties related to the transmitted information from said phase difference; and
`
`means for performing a feedback correction of said frequency deviation based on
`
`said determined frequency offset.
`
`An apparatus for performing a fine frequency synchronization compensating for a
`
`carrier frequency deviation from an oscillator frequency,
`
`for a multi-carrier
`
`demodulation system of the type capable of carrying out a differential phase
`
`decoding of multi—carrier modulated signals, said signals comprising a plurality of
`
`symbols, each symbol being defined by phase differences between simultaneous
`
`carriers having different frequencies, said apparatus comprising:
`
`means for determining respective phases of the same carrier in different symbols;
`
`M-PSK decision device for eliminating phase shift uncertainties related to the
`
`transmitted information from said phases to determine respective phase deviations;
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 6
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 6
`
`

`

`means for determining a frequency offset by determining a phase difference
`
`between said phase deviations;
`
`means for performing a feedback correction of said frequency deviation based on
`
`said determined frequency offset.
`
`29.
`
`The apparatus according to claim 27, further comprising:
`
`
`
`means for determining an averaged frequency offset by averaging determined
`
`frequency offsets of a plurality of carriers, wherein
`
`said means for performing a feedback correction performs said feedback correction
`
`of said frequency deviation based on said averaged frequency offset.
`
`30.
`
`The apparatus according to claim 28, further comprising:
`
`means for determining an averaged frequency offset by averaging determined
`
`frequency offsets of a plurality of carriers, wherein
`
`said means for performing a feedback correction performs said feedback correction
`
`of said frequency deviation based on said averaged frequency offset.
`
`31.
`
`The apparatus according to claim 27, wherein said means for determining a phase
`
`difference comprises means for determining a phase difference between phases of
`
`the same carrier in symbols which are adjacent in the time axis direction.
`
`32.
`
`The apparatus according to claim 28, wherein said means for determining respective
`
`phases comprises means for determining respective phases of the same carrier in
`
`symbols which are adjacent in the time axis direction.
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 7
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 7
`
`

`

`33.
`
`The apparatus according to claim 27, wherein said means for performing a feedback
`
`correction of said frequency deviation comprises a numerical controlled oscillator
`
`and a complex multiplier.
`
`34.
`
`The apparatus according to claim 33, wherein said means for performing a feedback
`
`correction of said frequency deviation further comprises a low path filter preceding
`
`said numerical controlled oscillator.
`
`REMARKS
`
`By the present Preliminary Amendment, claims 1-18 annexed to the International
`
`Preliminary Examination Report dated July 19, 2000 are being cancelled and replaced with
`
`new claims 19-34. In the new claims, multiple dependencies and parenthetical reference
`
`numerals have been eliminated.
`
`A substitute specification is being submitted to facilitate processing of this application.
`
`A marked—up copy of the substitute specification is also being provided to show the new
`
`changes which are beyond those previously made during the international stage. The
`
`
`
`substitute specification contains no new matter.
`
` Examiner have any questions, the Examiner is invited to contact the undersigned attorney at
`
`Early and favorable action on this application is respectfully requested. Should the
`
` the local telephone number listed below.
`
`Respectfully submitted,
`
`\/s£ (AM...
`
`John E. Holmes
`Attorney for Applicant
`Reg. No. 29,392
`
`Roylance, Abrams, Berdo 8?. Goodman
`1300 19th Street, N.W., Suite 600
`Washington, DC 20036-2680
`(202) 659-9076
`
`Dated: OM /
`
`2000
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 8
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 8
`
`

`

`5
`
`f
`
`’
`
`3M6
`
`09/673270
`529Rec’dPCT/PTO 13 ocrzooo
`
`’
`
`METHOD AND APPARATUS FOR FINE FREQUENCY SYNCHRONIZATION IN
`3""
`""’ "" _ w—m‘m
`MULTI-CARRIER DEMODULATION SYSTEMS
`
`
`FIELD OF THE INVENTION
`
`invention relates to methods and apparatus for
`The present
`performing a fine frequency synchronization in multi-carrier
`demodulation systems,
`and
`in particular
`to methods
`and
`apparatus for performing a fine frequency synchronization
`compensating for
`a carrier
`frequency deviation from an
`oscillator frequency in a multi—carrier demodulation system
`of
`the type capable of carrying out a differential phase
`decoding of multi—carrier modulated signals, wherein the
`signals comprise a plurality of symbols, each symbol being
`defined by phase differences between simultaneous carriers
`
`having different frequencies.
`
`BACKGROUND OF THE INVENTION
`
` effect of a carrier frequency offset is substantially more
`
`In a multi carrier transmission system (MCM, OFDM),
`
`the
`
`considerable than in a single carrier transmission system.
`
`MCM is more sensitive to phase noise and frequency offset
`
`which occurs
`
`as
`
`amplitude distortion and
`
`inter carrier
`
`interference (ICI). The inter carrier interference has the
`effect
`that
`the subcarriers are no
`longer orthogonal
`in
`
`relation to each other. Frequency offsets occur after power
`
`on or
`
`also later
`
`due
`
`to frequency deviation of
`
`the
`
`oscillators used for downconversion into baseband. Typical
`
`accuracies for the frequency of a free running oscillator
`are about
`:50 ppm of the carrier frequency. With a carrier
`frequency in the S-band of 2.34 Ghz, for example,
`there will
`be a maximum local oscillator
`(LO)
`frequency deviation of
`
`above 100 kHz
`
`(117.25 kHz). The above named effects result
`
`in high requirements on the algorithm used for
`
`frequency
`
`offset correction.
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 9
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 9
`
`

`

`
`
`DESCRIPTION OF PRIOR ART
`
`Most prior art algorithms
`
`for
`
`frequency synchronization
`
`divide frequency correction into two stages.
`
`In the first
`
`stage,
`
`a coarse synchronization is performed.
`
`In the second
`
`stage, a fine correction can be achieved. A frequently used
`
`algorithm for coarse synchronization of the carrier frequen—
`
`spec—
`cy uses a synchronization symbol which has a special
`tral pattern in the frequency domain. Such a synchronization
`
`symbol
`
`is,
`
`for example,
`
`a CAZAC sequence (CAZAC = Constant
`
`Amplitude Zero Autocorrelation). Through comparison,
`
`i.e.
`
`the correlation,
`
`of
`
`the power
`
`spectrum of
`
`the received
`
`signal with that of
`
`the transmitted signal,
`
`the frequency
`
`carrier offset can be coarsely estimated. These prior art
`
`algorithms all work in the frequency domain. Reference is
`
`made,
`
`for
`
`example,
`
`to Ferdinand ClaBen, Heinrich Meyr,
`
`"Synchronization Algorithms for an OFDM System for Mobile
`
`Communication",
`
`ITG-Fachtagung 130, Codierung fflr Quelle,
`
`Kanal und Ubertragung, pp. 105 — 113, Oct. 26—28, 1994; and
`
`Timothy M.
`
`Schmidl, Donald C. Cox,
`
`"Low-Overhead,
`
`Low-
`
`Complexity [Burst] Synchronization for OFDM",
`
`in Proceedings
`
`of
`
`the IEEE International Conference on Communication ICC
`
`1996, pp. 1301-1306 (1996).
`
`For
`
`the coarse synchronization of
`
`the carrier frequency,
`
`Paul H. Moose,
`
`"A Technique
`
`for Orthogonal Frequency
`
`Division Multiplexing Frequency Offset Correction",
`
`IEEE
`
`Transaction On Communications, Vol.
`
`42, No.
`
`10, October
`
`1994, suggest increasing the spacing between the subcarriers
`
`such that
`
`the
`
`subcarrier distance
`
`is greater
`
`than the
`
`maximum frequency difference between the received and trans-
`
`mitted carriers. The subcarrier distance is increased by
`
`reducing the number of sample values which are transformed
`
`by
`
`the Fast Fourier Transform. This
`
`corresponds
`
`to a
`
`reduction of the number of sampling values which are trans-
`
`formed by the Fast Fourier Transform.
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 10
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 10
`
`

`

`SUMMARY OF THE INVENTION
`
`It is an object of the present
`
`invention to provide methods
`
`and apparatus
`
`for performing a
`
`fine frequency'
`
`synchroni—
`
`zation which allow a fine frequency synchronization compen—
`
`sating for a carrier frequency deviation from an oscillator
`
`frequency in a MCM transmission system which makes use of
`
`MCM signals
`
`in which information is differential phase
`
`encoded between simultaneous sub—carriers having different
`
`frequencies.
`
`
`
`In accordance with a first aspect,
`
`the present
`
`invention
`
`provides a method of performing a fine frequency synchro—
`
`nization compensating for a carrier frequency deviation from
`
`an oscillator
`
`frequency in a multi—carrier demodulation
`
`system of
`
`the type capable of carrying out a differential
`
`phase decoding of multi—carrier modulated
`
`signals,
`
`the
`
`signals comprising a plurality of symbols, each symbol being
`defined by phase differences between simultaneous carriers
`
`having different
`
`frequencies,
`
`the method comprising the
`
`steps of:
`
`determining a phase difference between phases of
`
`the same
`
`carrier in different symbols;
`
`determining a frequency offset by eliminating phase shift
`
`uncertainties corresponding to codeable phase shifts from
`
`the phase difference; and
`
`performing a feedback correction of
`
`the carrier frequency
`
`deviation based on the determined frequency offset.
`
`In accordance with a second aspect,
`
`the present
`
`invention
`
`provides a method of performing a fine frequency synchro-
`
`nization compensating for a carrier frequency deviation from
`
`an oscillator
`
`frequency in a multi—carrier demodulation
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 11
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 11
`
`

`

`
`
`system of
`
`the type capable of carrying out a differential
`
`phase decoding of multi-carrier modulated signals,
`
`the
`
`signals comprising a plurality of symbols, each symbol being
`
`defined by phase differences between simultaneous carriers
`
`having different
`
`frequencies,
`
`the method comprising the
`
`steps of:
`
`determining
`
`respective
`
`phases
`
`of
`
`the
`
`same carrier
`
`in
`
`different symbols;
`
`eliminating phase
`
`shift uncertainties
`
`corresponding to
`
`codeable
`
`phase
`
`shifts
`
`from the
`
`phases
`
`to
`
`determine
`
`respective phase deviations;
`
`determining a
`
`frequency offset
`
`by determining a phase
`
`difference between the phase deviations; and
`
`performing a feedback correction of said carrier frequency
`
`deviation based on the determined frequency offset.
`
`In accordance with a third aspect,
`
`the present
`
`invention
`
`provides a method of performing a fine frequency synchro—
`
`nization compensating for a carrier frequency deviation from
`
`an oscillator
`
`frequency in a multi-carrier demodulation
`
`system of
`
`the type capable of carrying out a differential
`
`phase decoding of multi-carrier modulated
`
`signals,
`
`the
`
`signals comprising a plurality of symbols, each symbol being
`
`defined by phase differences between simultaneous carriers
`
`having different
`
`frequencies,
`
`the method comprising the
`
`steps of:
`
`for a plurality of carriers in the symbols:
`
`determining a phase difference between phases of the same
`
`carrier in different symbols; and
`
`determining a frequency offset by eliminating phase shift
`
`uncertainties corresponding to codeable phase shifts from
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 12
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 12
`
`

`

`
`
`
`the phase difference;
`
`determining and averaged frequency offset by averaging the
`
`determined frequency offset of
`and
`
`the plurality of carriers;
`
`performing a feedback correction of the frequency deviation
`
`based on the averaged frequency offset.
`
`In accordance with a fourth aspect,
`
`the present
`
`invention
`
`provides a method of performing a
`
`fine frequency synchro—
`
`nization compensating for a carrier frequency deviation from
`
`an oscillator
`
`frequency in a multi—carrier demodulation
`
`system of the type capable of carrying out a differential
`
`the
`signals,
`phase decoding of multi—carrier modulated
`signals comprising a plurality of symbols, each symbol being
`defined by phase differences between simultaneous carriers
`
`having different
`
`frequencies,
`
`the method comprising the
`
`steps of:
`
`for a plurality of carriers in the symbols:
`
`determining /respective phases of
`
`the
`
`same carrier
`
`in
`
`different symbols;
`
`eliminating phase shift uncertainties corresponding to
`
`codeable phase
`
`shifts
`
`from said phases
`
`to determine
`
`respective phase deviations; and
`
`determining a
`
`frequency offset
`
`by determining a phase
`
`difference between the phase deviations;
`
`determining an averaged frequency offset by averaging the
`
`determined frequency offsets of
`and
`
`the plurality of carriers;
`
`performing a feedback correction of the frequency deviation
`
`based on the averaged frequency offset.
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 13
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 13
`
`

`

`
`
`In accordance with a fifth aspect,
`
`the present
`
`invention
`
`provides
`
`an
`
`apparatus
`
`for performing a
`
`fine frequency
`
`synchronization
`
`compensating
`
`for
`
`a
`
`carrier
`
`frequency
`
`deviation from an oscillator frequency,
`
`for a multi-carrier
`
`demodulation system of
`
`the type capable of carrying out a
`
`differential
`
`phase
`
`decoding
`
`of multi—carrier modulated
`
`signals,
`
`the signals comprising a plurality of symbols, each
`
`symbol
`
`being
`
`defined
`
`by
`
`phase
`
`differences
`
`between
`
`simultaneous carriers
`
`having different
`
`frequencies,
`
`the
`
`apparatus comprising:
`
`means for determining a phase difference between phases of
`
`the same carrier in different symbols;
`
`means
`
`for determining a
`
`frequency offset by eliminating
`
`phase shift uncertainties corresponding to codeable phaSe
`
`shifts from the phase difference; and
`
`means for performing a feedback correction of the frequency
`
`deviation based on the determined frequency offset.
`
`In accordance with a sixth aspect,
`
`the present
`
`invention
`
`provides
`
`an
`
`apparatus
`
`for performing a
`
`fine frequency
`
`a
`for
`compensating
`synchronization
`deviation from an oscillator frequency,
`
`frequency
`carrier
`for a multi-carrier
`
`demodulation system of
`
`the type capable of carrying out a
`
`differential
`
`phase
`
`decoding
`
`of multi—carrier modulated
`
`signals,
`
`said signals comprising’ a plurality of
`
`symbols,
`
`each symbol being defined by phase differences between
`
`simultaneous carriers having different
`
`frequencies,
`
`the
`
`apparatus comprising:
`
`means for determining respective phases of the same carrier
`
`in different symbols;
`
`means
`
`for
`
`eliminating
`
`phase
`
`shift
`
`uncertainties
`
`corresponding to codeable phase shifts from the phases to
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 14
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 14
`
`

`

`determine respective phase deviations;
`
`means
`
`for determining a frequency offset by determining a
`
`phase difference between the phase deviations; and
`
`means for performing a feedback correction of the frequency
`
`deviation based on the determined frequency offset.
`
`In accordance with a seventh aspect,
`
`the present
`
`invention
`
`fine‘ frequency
`for performing a
`apparatus
`an
`provides
`synchronization
`compensating
`for
`a
`carrier
`frequency
`deviation from an oscillator frequency,
`for a multi-carrier
`
`demodulation system of the type capable of carrying out a
`
`of multi—carrier modulated
`decoding
`phase
`differential
`signals,
`the signals comprising a plurality of symbols, each
`symbol being defined by phase differences between simulta—
`neous carriers having different frequencies,
`the apparatus
`
`comprising:
`
`
`
` means
`
`means for determining a phase difference between phases of
`
`the same carrier in different symbols;
`
`for determining'
`a
`frequency offset by eliminating
`phase shift, uncertainties corresponding’
`to codeable phase
`
`shifts from the phase difference;
`
`by
`averaged frequency offset
`for determining an
`means
`averaging' determined frequency offsets of
`a plurality' of
`
`carriers; and
`
`means for performing a feedback correction of the frequency
`
`deviation based on the averaged frequency offset.
`
`In accordance with an eighth aspect,
`
`the present
`
`invention
`
`fine frequency
`for performing a
`apparatus
`an
`provides
`synchronization
`compensating
`for
`a
`carrier
`frequency
`deviation from an oscillator frequency, for a multi—carrier
`
`demodulation system of
`
`the type capable of carrying out a
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 15
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 15
`
`

`

`
`
`differential
`
`phase
`
`decoding
`
`of multi—carrier modulated
`
`signals,
`
`the signals comprising a plurality of symbols, each
`
`symbol being defined by phase differences between simulta—
`
`neous carriers having different frequencies,
`
`the apparatus
`
`comprising:
`
`means for determining respective phases of the same carrier
`
`in different symbols;
`
`means
`
`for
`
`eliminating
`
`phase
`
`shift
`
`uncertainties
`
`corresponding to codeable phase shifts from the phases to
`
`determine respective phase deviations;
`
`means
`
`for determining a frequency offset by determining a
`
`phase difference between the phase deviations;
`
`means
`
`for determining an
`
`averaged
`
`frequency offset
`
`by
`
`averaging' determined frequency offsets of
`
`a plurality' of
`
`carriers; and
`
`means for performing a feedback correction of the frequency
`
`deviation based on the averaged frequency offset.
`
`The present
`
`invention relates to methods and apparatus for
`
`performing a fine frequency synchronization compensating for
`
`a carrier frequency deviation from an oscillator frequency.
`
`This fine frequency synchronization is preferably performed
`
`after completion of a coarse frequency synchronization, such
`
`that
`
`the
`
`frequency offsets after
`
`the
`
`coarse
`
`frequency
`
`synchronization are
`
`smaller
`
`than half
`
`the
`
`sub—carrier
`
`distance in the MCM signal. Since the frequency offsets
`
`which are to be corrected by the inventive fine frequency
`
`synchronization methods and apparatus,
`
`a correction of the
`
`frequency
`
`offsets
`
`by
`
`using
`
`a
`
`phase
`
`rotation with
`
`differential decoding and de—mapping in the time axis can be
`
`used. The frequency offsets are detected by determining the
`
`frequency differences between time contiguous sub-carrier
`
`symbols
`
`along the
`
`time
`
`axis.
`
`The
`
`frequency
`
`error
`
`is
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 16
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 16
`
`

`

`
`
`calculated by measuring the rotation of
`
`the I—Q cartesian
`
`coordinates of each sub-carrier and,
`
`in preferred embodi—
`
`ments,
`
`averaging them over all
`
`n
`
`sub—carriers of
`
`a MCM
`
`symbol.
`
`Firstly,
`
`the phase ambiguity or uncertainty is eliminated by
`
`using a M—PSK decision device and correlating the output of
`
`the decision device with the input signal for a respective
`
`sub—carrier symbol. Thus,
`
`the phase offset for a sub-carrier
`
`symbol
`
`is determined and can be used for restructuring the
`
`frequency error
`
`in form of
`
`a
`
`feed—backward
`
`structure.
`
`Alternatively,
`
`the phase offsets of the sub—carrier symbols
`
`of one MCM symbol can be averaged over all of
`
`the active
`
`carriers of a MCM symbol, wherein the averaged phase offset
`
`is used to restructure the frequency error.
`
`In accordance with the present
`
`invention,
`
`the determination
`
`is performed in the frequency
`the frequency offset
`of
`domain. The
`feedback correction in accordance with the
`
`inventive fine frequency synchronization is performed in the
`
`time domain. To this end, a differential decoder in the time
`
`domain is provided in order to detect
`
`frequency offsets of
`
`sub-carriers on the basis of the phases of timely successive
`
`sub—carrier symbols of different MCM symbols.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`In the
`
`following, preferred embodiments of
`
`the present
`
`invention will be explained in detail on the basis of the
`
`drawings enclosed,
`
`in which:
`
`Figure 1
`
`shows a schematic overview of a MCM transmission
`
`system to which the present application can be
`
`applied;
`
`Figures 2A and 28 show schematic views representing a scheme
`
`for differential mapping in the time axis and a
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 17
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 17
`
`

`

`
`
`_10_
`
`scheme for differential mapping in the frequency
`
`axis;
`
`Figure 3
`
`shows a functional block diagram for performing a
`
`differential mapping in the frequency axis;
`
`Figure 4
`
`shows a representation of
`
`time variation of all
`
`sub-carriers in MCM symbols;
`
`Figure 5
`
`shows
`
`a QPSK—constellation for each sub-carrier
`
`with a frequency offset;
`
`Figure 6
`
`shows
`
`a general block diagram illustrating the
`
`position
`
`of
`
`the
`
`inventive
`
`fine
`
`frequency
`
`synchronization device in a MCM receiver;
`
`Figure 7
`
`shows a block diagram of the fine frequency error
`
`detector shown in Figure 6;
`
`Figure 8
`
`shows
`
`a
`
`block
`
`diagram of
`
`a
`
`MCM
`
`receiver
`
`comprising a
`
`coarse
`
`frequency synchronization
`
`unit and a fine frequency synchronization unit;
`
`Figure 9
`
`shows a block diagram of a unit for performing a
`
`coarse frequency synchronization;
`
`Figure 10
`
`shows a schematic view of a refer