Clipping of transmission signal
AssigneeNokia Siemens Networks Oy
InventorOlli Piirainen
Life of this patent
Estimating the term…
Abstract
A transmitter clips a transmission signal before transmission in order to reduce the strength of at least one peak of the transmission signal exceeding a predetermined threshold. The transmitter includes a clipper having a minimizer, a filter and an adder. The minimizer minimizes of a cost function with respect to an optimization signal, the cost function having weighted terms as a function of the optimization signal. The terms relate to an effective modulation distortion and an effective overshoot exceeding the predetermined threshold. The filter forms a clipping signal by filtering the optimization signal formed as a result of the minimization according to the spectrum emission mask requirements of the radio system. The adder subtracts the clipping signal from the transmission signal.
Claims27
A method, comprising:
- clipping a transmission signal in a transmitter before transmission in order to reduce a strength of at least one peak of the transmission signal exceeding a predetermined threshold;
- performing a minimization of a cost function with respect to an optimization signal, wherein the cost function is a function of the optimization signal, and the cost function has a first weighted term associated with an effective modulation distortion function and a second weighted term associated with an effective overshoot exceeding the predetermined threshold;
- forming a clipping signal by filtering the optimization signal formed as a result of the minimization according to spectrum emission mask requirements of a radio system;
- and subtracting the clipping signal from the transmission signal.
An apparatus, comprising:
- a clipper configured to clip a transmission signal before transmission in order to reduce a strength of at least one peak of the transmission signal exceeding a predetermined threshold;
- a minimizer configured to minimize a cost function with respect to an optimization signal, wherein the cost function is a function of the optimization signal, and the cost function has a first weighted term associated with an effective modulation distortion function and a second weighted term associated with an effective overshoot exceeding the predetermined threshold;
- a filter configured to form a clipping signal by filtering the optimization signal formed as a result of a minimization according to spectrum emission mask requirements of a radio system;
- and a subtracter configured to subtract the clipping signal from the transmission signal.
An apparatus, comprising:
- clipping means for clipping a transmission signal before transmission in order to reduce a strength of at least one peak of the transmission signal exceeding a predetermined threshold;
- minimizing means for minimizing a cost function with respect to an optimization signal, wherein the cost function is a function of the optimization signal, and the cost function has a first weighted term associated with an effective modulation distortion function and a second weighted term associated with an effective overshoot exceeding the predetermined threshold;
- forming means for forming a clipping signal by filtering the optimization signal formed as a result of a minimization according to spectrum emission mask requirements of a radio system;
- and subtracting means for subtracting the clipping signal from the transmission signal.
A computer program embodied on a computer readable storage medium, the program configured to control a processor to perform a process, the process comprising:
- clipping a transmission signal in a transmitter of a radio system before transmission in order to reduce a strength of at least one peak of the transmission signal exceeding a predetermined threshold;
- performing a minimization of a cost function with respect to an optimization signal, wherein the cost function is a function of the optimization signal, and the cost function has a first weighted term associated with an effective modulation distortion function and a second weighted term associated with an effective overshoot exceeding the predetermined threshold;
- forming a clipping signal by filtering the optimization signal formed as a result of the minimization according to spectrum emission mask requirements of a radio system;
- and subtracting the clipping signal from the transmission signal.
Dependencies are inferred from the claim text.