US 6,687,511 B2 · CDMA transmit peak power reduction

Abstract

A peak power regulator is disclosed that functions within a Code Division Multiple Access (CDMA) transmitter to reduce peak power spikes within baseband signals while maintaining the average output power consistent with the average input power, controlling the out-of-band emissions, and maintaining the in-band signal quality within an acceptable degradation. In-phase and quadrature baseband signals are input to a delay block and an envelope magnitude predictor within the peak power regulator. The envelope magnitude predictor outputs an estimate for the magnitude of the envelope that will be generated when the inputted baseband signals are modulated. This estimate is input to a multiplier that generates a ratio by dividing the estimate by a maximum acceptable envelope magnitude. The ratio is subsequently input to a mapping table that outputs a scaling factor sufficient for reducing peak power spikes. The scaling factor is subsequently input to an optional mean power regulator that generates an instantaneous gain value sufficient to maintain the average output power level at the average input power level. This gain value is applied to two multipliers that are also input with delayed versions of the in-phase and quadrature baseband input signals. The outputs from these two multipliers, after being filtered within lowpass filters to remove out-of-band emissions caused by the scaling, are output from the peak power regulator. These peak power reduced outputs have any peak power spikes scale reduced while maintaining the average power constant.

Claims13

Dependent claims

A peak power regulator, input with at least one input signal, that outputs at least one output signal corresponding to the input signal, the power regulator comprising:

a delay apparatus that generates a delayed signal corresponding to the input signal;
a power estimation apparatus that generates, with use of the input signal, an overall input power estimation signal corresponding to the input signal;
a scaling factor generator that generates a scaling factor with use of the overall input power estimation signal and a maximum acceptable power signal;
a power scaling apparatus that multiplies the delayed signal by the scaling factor to generate a scaled signal corresponding to the output signal;
and
a filtering apparatus that filters the scaled signal to generate the output signal.

3 more elements

An envelope magnitude regulator, input with at least one IF input signal, that outputs at least one IF output signal corresponding to the IF input signal, the envelope magnitude regulator comprising:

a delay apparatus that generates a delayed IF signal corresponding to the IF input signal;
an envelope magnitude estimation apparatus that generates, with use of the IF input signal, an overall input envelope magnitude estimation signal corresponding to the IF input signal;
a scaling factor generator that generates a scaling factor with use of the overall input envelope magnitude estimation signal and a maximum acceptable envelope magnitude signal;
an envelope magnitude scaling apparatus that multiplies the delayed IF signal by the sealing factor to generate a scaled IF signal corresponding to the IF output signal;
and
a filtering apparatus that filters the scaled IF signal to generate the IF output signal.

3 more elements

Dependencies are inferred from the claim text.

CDMA transmit peak power reduction

Life of this patent

CDMA transmit peak power reduction

Life of this patent

Abstract

Claims13