Transmitter and the method therefor
First Claim
1. A method for reducing a peak-to-average power ratio (PAPR), the method being applied by using N sub-carriers, L sub-carriers of the N sub-carriers being reserved sub-carriers, L being less than N, the method comprising:
- receiving a data signal, the envelope power of the data signal having a constant power and a fluctuant power;
generating L reserved sub-carrier symbols of the L sub-carriers located in the reserved sub-carriers;
modifying the L reserved sub-carrier symbols according to the data signal, and generating a to-be-combined signal accordingly; and
combining the to-be-combined signal into the data signal in frequency domain;
wherein the data signal has N data symbols located in the N sub-carriers, the N data symbols correspond to an aperiodic auto-correlation function (AACF) vector, the L reserved sub-carrier symbols correspond to a reserved sub-carrier symbol vector, and in the step of modifying the L reserved sub-carrier symbols, the L reserved sub-carrier symbols are modified according to a gradient or any other algorithmic methods of the square of the absolute value of the AACF vector at the reserved sub-carrier symbol vector, or modified according to the absolute value for the AACF vector to the pth power, wherein p is larger than 0.
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Accused Products
Abstract
A transmitter and the method therefor are provided. The transmitter is applied in an orthogonal frequency division multiplexing (OFDM) based or other multicarrier communication systems. The transmitter uses N sub-carriers. Among the N sub-carriers, L sub-carriers (or tones) are reserved for PAPR reduction. L is less than N. The method includes the following steps. Original frequency domain data symbols are generated and fed into the reserved-tone symbol generation unit. The reserved-tone symbols are generated by using pure frequency domain signal processing. Then the reserved-tone symbols are combined with original data symbols to generate combined PAPR reduction signal. The resultant PAPR reduction signal can be fed into reserved-tone symbol generation unit iteratively to obtain updated reserved-tone symbols. For proper iterations, the original data symbols combined with L frequency domain reserved-tone symbols will result in lower PAPR transmit signal.
10 Citations
10 Claims
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1. A method for reducing a peak-to-average power ratio (PAPR), the method being applied by using N sub-carriers, L sub-carriers of the N sub-carriers being reserved sub-carriers, L being less than N, the method comprising:
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receiving a data signal, the envelope power of the data signal having a constant power and a fluctuant power; generating L reserved sub-carrier symbols of the L sub-carriers located in the reserved sub-carriers; modifying the L reserved sub-carrier symbols according to the data signal, and generating a to-be-combined signal accordingly; and combining the to-be-combined signal into the data signal in frequency domain; wherein the data signal has N data symbols located in the N sub-carriers, the N data symbols correspond to an aperiodic auto-correlation function (AACF) vector, the L reserved sub-carrier symbols correspond to a reserved sub-carrier symbol vector, and in the step of modifying the L reserved sub-carrier symbols, the L reserved sub-carrier symbols are modified according to a gradient or any other algorithmic methods of the square of the absolute value of the AACF vector at the reserved sub-carrier symbol vector, or modified according to the absolute value for the AACF vector to the pth power, wherein p is larger than 0. - View Dependent Claims (2, 3)
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4. A method for reducing a peak-to-average power ratio (PAPR), the method being applied by using N sub-carriers, L sub-carriers of the N sub-carriers being reserved sub-carriers, L being less than N, the method comprising:
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receiving a data signal, the envelope power of the data signal having a constant power and a fluctuant power; generating L reserved sub-carrier symbols of the L sub-carriers located in the reserved sub-carriers; modifying the L reserved sub-carrier symbols according to the data signal, and generating a to-be-combined signal accordingly; and combining the to-be-combined signal into the data signal in frequency domain; wherein the L reserved sub-carrier symbols are divided into several groups of reserved sub-carrier symbols, and in the step of modifying the L reserved sub-carrier symbols, the several groups of reserved sub-carrier symbols are modified sequentially or in parallel so as to modify the L reserved sub-carrier symbols.
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5. A method for reducing a peak-to-average power ratio (PAPR), the method being applied by using N sub-carriers, L sub-carriers of the N sub-carriers being reserved sub-carriers, L being less than N, the method comprising:
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receiving a data signal, the envelope power of the data signal having a constant power and a fluctuant power; generating L reserved sub-carrier symbols of the L sub-carriers located in the reserved sub-carriers; modifying the L reserved sub-carrier symbols according to the data signal, and generating a to-be-combined signal accordingly; and combining the to-be-combined signal into the data signal in frequency domain; wherein the transmitter comprises a filter, the filter has a frequency response function denoted as H, Hk denotes the frequency response coefficient at the kth sub-carrier, the data signal has N data symbols located in N sub-carriers, and the step of modifying the L reserved sub-carrier symbols comprises the following steps; multiplying the N data symbols with a corresponding Hk, respectively; modifying the L reserved sub-carrier symbols according to the N data symbols being multiplied with Hk; and multiplying the to-be-combined signal with 1/Hk; wherein the to-be-combined signal being multiplied with 1/Hk is served as the to-be-combined signal for use in combining with the data signal.
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6. A transmitter, applied in an orthogonal frequency division multiplexing (OFDM) based system, the transmitter using N sub-carriers, L sub-carriers of the N sub-carriers being reserved sub-carriers, L being less than N, the transmitter comprising:
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a modulation unit, for outputting a data signal, the envelope power of the data signal having a constant power and a fluctuant power; a reserved sub-carrier symbol generation unit, for generating L reserved sub-carrier symbols of the L sub-carriers located in the reserved sub-carriers, for modifying the L reserved sub-carrier symbols according to the data signal and generating a to-be-combined signal accordingly; and a combination unit, for combining the to-be-combined signal into the data signal in frequency domain; wherein the data signal has N data symbols located in the N sub-carriers, the N data symbols correspond to an aperiodic auto-correlation function (AACF) vector, the L reserved sub-carrier symbols correspond to a reserved sub-carrier symbol vector, and the modulation unit modifies the L reserved sub-carrier symbols according to a gradient or any other algorithmic methods of the square of the absolute value of the AACF vector at the reserved sub-carrier symbol vector, or according to the absolute value for the AACF vector to the pth power, wherein p is larger than 0. - View Dependent Claims (7, 8)
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9. A transmitter, applied in an orthogonal frequency division multiplexing (OFDM) based system, the transmitter using N sub-carriers, L sub-carriers of the N sub-carriers being reserved sub-carriers, L being less than N, the transmitter comprising:
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a modulation unit, for outputting a data signal, the envelope power of the data signal having a constant power and a fluctuant power; a reserved sub-carrier symbol generation unit, for generating L reserved sub-carrier symbols of the L sub-carriers located in the reserved sub-carriers, for modifying the L reserved sub-carrier symbols according to the data signal and generating a to-be-combined signal accordingly; and a combination unit, for combining the to-be-combined signal into the data signal in frequency domain; wherein the L reserved sub-carrier symbols comprise several groups of reserved sub-carrier symbols, and the modulation unit modifies the L reserved sub-carrier symbols sequentially or in parallel, so as to modify the L reserved sub-carrier symbols.
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10. A transmitter, applied in an orthogonal frequency division multiplexing (OFDM) based system, the transmitter using N sub-carriers, L sub-carriers of the N sub-carriers being reserved sub-carriers, L being less than N, the transmitter comprising:
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a modulation unit, for outputting a data signal, the envelope power of the data signal having a constant power and a fluctuant power; a reserved sub-carrier symbol generation unit, for generating L reserved sub-carrier symbols of the L sub-carriers located in the reserved sub-carriers, for modifying the L reserved sub-carrier symbols according to the data signal and generating a to-be-combined signal accordingly; and a combination unit, for combining the to-be-combined signal into the data signal in frequency domain; wherein the data signal has N data symbols located in N sub-carriers, and the transmitter further comprises; a filter, having a frequency response function denoted as H, wherein Hk denotes the frequency response coefficient at the kth sub-carrier a first multiplier, for multiplying the N data symbols with a corresponding Hk, respectively, wherein the reserved sub-carrier symbol generation unit modifies the L reserved sub-carrier symbols according to the N data symbols being multiplied with Hk, and generating the to-be-combined signal accordingly; a second multiplier, for multiplying the to-be-combined signal with 1/Hk, and for outputting the multiplied signal to the combination unit; and a conversion unit, for converting the data signal being processed by the combination unit into a time-domain transmitting signal, and for outputting the transmitting signal to the filter.
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Specification