Method and apparatus for reducing a crest factor of a multi-tone data signal
First Claim
Patent Images
1. Method for reducing a crest factor of a multi-tone-data signal which is transmitted in a predetermined transmission frequency band Δ
- F, wherein a multi-tone-correction signal is subtracted from said multi-tone-data signal, said multi-tone correction signal comprising a plurality of tone signals having frequencies outside said transmission frequency band Δ
F, and the method comprising the following steps;
(a) storing in a first memory at least one data symbol of a data symbol sequence, each data symbol comprising a predetermined number of data samples s(i) with index i, 0>
=i>
=(N−
1),(b) comparing the amplitude of each data sample of said data symbol with a first threshold value to detect a data sample peak;
(c) performing the following steps when a data sample peak is detected;
(i) reading a multi-tone-correction signal comprising a corresponding number of correction data samples from a second memory;
(ii) shifting cyclically the read correction data samples of the multi-tone correction signal so that the maximum of said correction data samples coincides with the detected data sample peak;
(iii) scaling of the shifted correction data samples of the multi-tone-correction signal according to a predetermined spectrum mask;
(iv) accumulating the scaled correction data samples of the multi-tone-correction signal in a third memory;
(d) subtracting the accumulated correction data samples of the multi-tone-correction signal from the data samples of said data symbol.
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Abstract
A crest factor reduction circuit for reducing a crest factor (CF) of a multi-tone-data signal which is transmitted in a predetermined transmission frequency band,
wherein the crest factor reduction circuit (8) comprises means (34) for subtracting a multi-tone-correction signal from said multi-tone-data signal,
wherein the multi-tone-correction signal comprises a plurality of tone signals having frequencies outside said transmission frequency band.
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Citations
42 Claims
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1. Method for reducing a crest factor of a multi-tone-data signal which is transmitted in a predetermined transmission frequency band Δ
- F, wherein a multi-tone-correction signal is subtracted from said multi-tone-data signal, said multi-tone correction signal comprising a plurality of tone signals having frequencies outside said transmission frequency band Δ
F, and the method comprising the following steps;(a) storing in a first memory at least one data symbol of a data symbol sequence, each data symbol comprising a predetermined number of data samples s(i) with index i, 0>
=i>
=(N−
1),(b) comparing the amplitude of each data sample of said data symbol with a first threshold value to detect a data sample peak; (c) performing the following steps when a data sample peak is detected; (i) reading a multi-tone-correction signal comprising a corresponding number of correction data samples from a second memory; (ii) shifting cyclically the read correction data samples of the multi-tone correction signal so that the maximum of said correction data samples coincides with the detected data sample peak; (iii) scaling of the shifted correction data samples of the multi-tone-correction signal according to a predetermined spectrum mask; (iv) accumulating the scaled correction data samples of the multi-tone-correction signal in a third memory; (d) subtracting the accumulated correction data samples of the multi-tone-correction signal from the data samples of said data symbol. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
- F, wherein a multi-tone-correction signal is subtracted from said multi-tone-data signal, said multi-tone correction signal comprising a plurality of tone signals having frequencies outside said transmission frequency band Δ
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12. A crest factor reduction circuit for reducing a crest factor of a multi-tone-data signal which is transmitted in a predetermined transmission frequency band Δ
- F, wherein the crest factor reduction circuit comprises means for subtracting a multi-tone-correction signal from said multi-tone-data signal, wherein the multi-tone-correction signal comprises a plurality of tone signals having frequencies outside said transmission frequency band Δ
F, wherein the crest factor reduction circuit has a data input for receiving a data symbol sequence of a data transmission signal, and wherein a first memory is provided for storing at least one data symbol of the received data symbol sequence, each data symbol comprising a predetermined number of data samples. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
- F, wherein the crest factor reduction circuit comprises means for subtracting a multi-tone-correction signal from said multi-tone-data signal, wherein the multi-tone-correction signal comprises a plurality of tone signals having frequencies outside said transmission frequency band Δ
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24. A crest factor reduction circuit for reducing a crest factor of a multi-tone-data signal which is transmitted in a predetermined transmission frequency band Δ
- F, wherein the crest factor reduction circuit comprises means for subtracting a multi-tone-correction signal from said multi-tone-data signal, wherein the multi-tone-correction signal comprises a plurality of tone signals having frequencies outside said transmission frequency band Δ
F, and wherein a second memory is provided for storing at least one multi-tone-correction signal comprising correction data samples, wherein the number of correction data samples corresponds to a number of data samples of a data symbol. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32)
- F, wherein the crest factor reduction circuit comprises means for subtracting a multi-tone-correction signal from said multi-tone-data signal, wherein the multi-tone-correction signal comprises a plurality of tone signals having frequencies outside said transmission frequency band Δ
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33. A transceiver for transceiving a data signal comprising:
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(a) a coding unit for generating a multi-tone-signal from a received data bit stream; (b) a IFFT unit for performing an inverse fast fourier transformation to generate a multi-tone-data signal comprising a sequence of data symbols, each having a predetermined number (N) of data samples s(i) with index i, 0<
=i<
=(N−
1);(c) a crest factor reduction circuit for reducing a crest factor of the multi-tone-data signal which is transmitted in a predetermined transmission frequency band, wherein the crest factor reduction circuit comprises means for subtracting a multi-tone-correction signal from said multi-tone-data signal, wherein the multi-tone-correction signal comprises a plurality of tone signals having frequencies outside said transmission frequency band; and (d) a transmission signal path for forming an analog transmission signal from the corrected multi-tone-data signal. - View Dependent Claims (34, 35, 36, 37, 38, 39, 40, 41, 42)
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Specification