Method and apparatus for peak-to-average power reduction
AssigneeQUALCOMM Incorporated
InventorsCharles E. Wheatley III, Rashid A. Attar
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Abstract
A method and system that reduces the peak-to-average power ratio of a reverse link signal is described. A baseband structure implements a peak reduction technique using peak windowing. A non-rectangular window is used to distort the signal. One embodiment of the window is an inverted-raised cosine with the peak reduction a function of the relative difference in the squared-magnitude of the envelope relative to that of the desired peak-to-average power ratio. Multiple passes through the peak-reduction function may be performed until a desired target peak-to-average power ratio is achieved.
Claims20
An apparatus, comprising:
- a peak-to-average reduction module that is configured to generate a reduced peak-to-average signal, in response to a peak in a signal that exceeds a target threshold value, by applying a reduction function continually to the peak and terminating the application of the reduction function when the peak is reduced to or below the target threshold value;
- and
- a power amplifier that is configured to amplify the reduced peak-to-average signal.
An apparatus, comprising:
- means for generating a reduced peak-to-average signal, in response to a peak in a signal that exceeds a target threshold value, by applying a reduction function to the peak until the peak is reduced to or below the target threshold value;
- and
- means for amplifying the reduced peak-to-average signal and to generate an amplified signal.
An apparatus, comprising:
- a reverse link modulator configured to provide channel data;
- a channel gain calculation module coupled to said reverse link modulator and configured to calculate reverse link channel gain;
- an averaging module that is coupled to said channel gain calculation module and configured to calculate average power of channels on the reverse link;
- a threshold module coupled to said averaging module and configured to generate envelope thresholds using a target peak-to-average ratio of the signal and said average power;
- a window weight module coupled to said threshold module and configured to align a window with a signal peak and generate window weights to be used for multiplying with filtered samples;
- a filter coupled to said reverse link modulator and configured to filter an n-chip (where n is an integer) sample of channel data to generate filtered samples;
- and
- a multiply module coupled to said filter and configured to multiply the filtered samples with an aligned peak window using the window weights from the window weight module, to create modified samples with a reduced peak-to-average power ratio.
A method of processing a signal, comprising:
- comparing a peak of the signal to a target threshold value;
- and
- applying a reduction function continually to the peak if the peak is above the target threshold value to generate a reduced peak-to-average signal;
- and
- terminating the application of the reduction function when the peak is at or below the target threshold value.
A method of processing a signal, comprising:
- calculating a gain value for the signal on a reverse link;
- calculating average power levels of channels on the reverse link;
- generating envelope thresholds using a target peak-to-average ratio of the signal and the average power levels;
- aligning a window with a peak of the signal;
- generating window weights for multiplying with filtered samples of the signal;
- filtering an n-chip (where n is an integer) sample of channel data to generate the filtered samples;
- and
- multiplying the filtered samples with an aligned peak window using the window weights to create modified samples with a reduced peak-to-average power ratio.
Dependencies are inferred from the claim text.