Digital broadcasting receiver
First Claim
1. A digital broadcasting receiver for receiving a digital broadcast transmitted by an orthogonal frequency division multiplexing OFDM transmission system in which each of a plurality of carriers is phase-modulated, comprising:
- FFT processing means for converting an OFDM signal expressed in the time domain into demodulation data expressed in the frequency domain; and
frequency deviation detecting means for detecting a phase error for each of the plurality of carriers by first multiplying, for each element, a demodulation data vector of phase reference symbols with a defined complex conjugate vector of the phase reference symbols, then multiplying elements in a vector obtained by the first multiplication which are equally separated from a center element at a particular carrier frequency, and adding the results of the latter multiplication;
wherein solutions obtained by said frequency deviation detecting means for a correspondence in a particular relation between said demodulation data vector of phase reference symbols and said defined complex conjugate vector of phase reference symbols and correspondence in which elements of said demodulation data vector of phase reference symbols and of said defined complex conjugate vector of phase reference symbols are mutually shifted from said particular relation by a plurality of elements, a correspondence which provides a maximum absolute value is obtained, and synchronization control is provided based on a difference of an obtained correspondence from said particular relation and said carrier frequency for said center element.
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Abstract
It is an object to correct a frequency deviation at the time of reception of a digital signal in which each carrier is subjected to phase modulation and orthogonal frequency division multiplexing (OFDM). A vector of fixed pattern symbols for reference of received carriers is multiplied by a vector of conjugate complex numbers of the defined values for each element. In the result, elements separated by the same numbers forward and backward from an element at a particular carrier frequency are multiplied together and the results are added. The same processing is applied to cases in which the elements of the vectors are mutually shifted by a plurality of elements from a certain correspondence and synchronization control to the broadcasting frequency is provided on the basis of a value which maximizes the absolute value in the results of the addition and the correspondence at that time.
88 Citations
19 Claims
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1. A digital broadcasting receiver for receiving a digital broadcast transmitted by an orthogonal frequency division multiplexing OFDM transmission system in which each of a plurality of carriers is phase-modulated, comprising:
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FFT processing means for converting an OFDM signal expressed in the time domain into demodulation data expressed in the frequency domain; and frequency deviation detecting means for detecting a phase error for each of the plurality of carriers by first multiplying, for each element, a demodulation data vector of phase reference symbols with a defined complex conjugate vector of the phase reference symbols, then multiplying elements in a vector obtained by the first multiplication which are equally separated from a center element at a particular carrier frequency, and adding the results of the latter multiplication; wherein solutions obtained by said frequency deviation detecting means for a correspondence in a particular relation between said demodulation data vector of phase reference symbols and said defined complex conjugate vector of phase reference symbols and correspondence in which elements of said demodulation data vector of phase reference symbols and of said defined complex conjugate vector of phase reference symbols are mutually shifted from said particular relation by a plurality of elements, a correspondence which provides a maximum absolute value is obtained, and synchronization control is provided based on a difference of an obtained correspondence from said particular relation and said carrier frequency for said center element. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A digital broadcasting receiver for receiving a digital broadcast transmitted by an orthogonal frequency division multiplexing OFDM transmission system in which each of a plurality of carriers is phase-modulated, comprising:
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symbol selecting means for partitioning a received digital signal represented in the time domain into symbols; region converting means for obtaining demodulation data represented in the frequency domain based on said symbols partitioned by said symbol selecting means; phase correcting means for multiplying, for each element, a demodulation data vector of phase reference symbols by a defined complex conjugate vector of phase reference symbols; inverse FFT processing means for applying inverse FFT processing to an output of said phase correcting means; timing variation detecting means for detecting a peak result of said inverse FFT processing means and detecting a timing shift at which said symbol selecting means partitions symbols according to a position of said peak; timing control means for controlling timing at which said symbol selecting means partitions symbols according to a timing shift detected by said timing variation detecting means; and product-sum operation means for multiplying elements equally separated from a center element at a particular carrier frequency in an output vector of said phase correcting means and adding the results; wherein said phase correcting means provides, to said inverse FFT processing means, an output based on a correspondence between said demodulation data vector of phase reference symbols and said defined complex conjugate vector of phase reference symbols which provides a maximum absolute value solution of the solutions provided by said phase correcting means and said product-sum operation means for a correspondence in a particular relation, and correspondences in which elements of said demodulation data vector of phase reference symbols and of said defined complex conjugate vector of phase reference symbols are mutually shifted from said particular relation by a plurality of elements. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A digital broadcasting receiver for receiving a digital broadcast transmitted by an orthogonal frequency division multiplexing OFDM transmission system in which each of a plurality of carriers is phase-modulated, comprising:
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FFT processing means for converting a received OFDM signal expressed in the time domain into demodulation data expressed in the frequency domain; phase correcting means for multiplying, for each element, a demodulation data vector of phase reference symbols output by said FFT processing means by a defined complex conjugate vector of phase reference symbols; product-sum operation means for multiplying elements equally separated from a center element at a particular carrier frequency in an output vector of said phase correcting means, and adding the results of multiplication; carrier shift means for shifting correspondence between elements of said demodulation data vector and carrier frequencies; and control means for controlling said carrier shift means, wherein said phase correcting means and said product-sum operation means function when a correspondence between said demodulation data vector of phase reference symbols and said defined complex conjugate vector of phase reference symbols has a particular relation, and when elements of said demodulation data vector of phase reference symbols and defined complex conjugate vector of phase reference symbols are mutually shifted from the particular relation by a plurality of elements, a correspondence which provides a maximum absolute value result is obtained, and said control means controls said carrier shift means based on a difference of an obtained correspondence from said particular relation and said carrier frequency for said center element. - View Dependent Claims (18, 19)
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Specification