Method and system for crest factor reduction
AssigneeTexas Instruments Incorporated
InventorsZigang Yang, Fernando A. Mujica, Gregory Copeland, Murtaza Ali
Life of this patent
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Abstract
An apparatus and system are provided for crest factor reduction (CFR). Preferably, a peak from the wideband signal is detected. A gain from the magnitude of the peak and a threshold can then be calculated. Based on this information, each carrier's contribution to the peak can be approximated, and a cancellation pulse coefficient for each carrier from its contribution to the peak can be calculated. A base cancellation pulse can be calculated from the cancellation pulse coefficients for each carrier, and a cancellation pulse can be calculated from the base cancellation pulse and the gain, which can then be applied to the wideband signal.
Claims15
An apparatus comprising:
- an input section that receives an input signal and that generates an intermediate signal, wherein the input section includes:
- an interface that receives the input signal and that generates a wideband signal;
- a crest factor reduction (CFR) unit that reduces a peak-to-average ratio (PAR) of the wideband signal, wherein the CFR unit has a stage that includes:
- a peak detector that detects a peak from the wideband signal;
- and
- a cancellation pulse calculator that is coupled to the peak detector and that calculates a cancellation pulse having an envelop and phase information that are approximately the same as the peak;
- output logic that receives a signal the wideband signal from the CFR unit having a reduced PAR and that generates the intermediate signal;
- and
- an output section that receives the intermediate signal and that generates a transmission signal.
A system for generating and transmitting a transmission signal, the system comprising:
- an input section that receives an input signal and that generates an intermediate signal, wherein the input section includes:
- an interface that receives the input signal and that generates a wideband signal;
- a crest factor reduction (CFR) unit that that reduces a peak-to-average ratio (PAR) of the wideband signal, wherein the CFR unit has a stage that includes:
- a peak detector that detects a peak from the wideband signal;
- and
- a cancellation pulse calculator that is coupled to the peak detector and that calculates a cancellation pulse having an envelop and phase information that are approximately the same as the peak;
- output logic that receives a signal the wideband signal from the CFR unit having a reduced PAR and that generates the intermediate signal;
- an output section that receives the intermediate signal and that generates a digital transmission signal;
- transmission circuitry that receives the digital transmission signal and generates a radio frequency (RF) signal;
- and
- an antenna that outputs the RF signal.
A computer program product for reducing a PAR of a wideband signal in a transmission processor, the computer program product comprising:
- computer code for detecting a peak from the wideband signal;
- computer code for calculating a gain from the magnitude of the peak and a threshold;
- computer code for approximating each carrier's contribution to the peak;
- computer code for calculating a cancellation pulse coefficient for each carrier from its contribution to the peak;
- computer code for calculating a base cancellation pulse from the cancellation pulse coefficients for each carrier;
- computer code for calculating a cancellation pulse from the base cancellation pulse and the gain;
- and
- computer code for applying the cancellation pulse to the wideband signal.
Dependencies are inferred from the claim text.