Look up table-based sum predistorter for power amplifification with concurrent dual band inputs
AssigneeTelefonaktiebolaget L M Ericsson (publ)
InventorChunlong Bai
Life of this patent
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Abstract
A method and system for pre-distorting a dual band signal to compensate for distortion of a non-linear power amplifier in a radio transmitter are disclosed. In one embodiment, the first signal of the dual band signal is tuned to a first intermediate frequency to produce a first tuned signal and the second signal of the dual band signal is tuned to minus the intermediate frequency to produce a second tuned signal. A single input pre-distorter pre-distorts the sum of the first tuned signal and the second tuned signal. The coefficients of the pre-distorter are obtained from a one-dimensional look-up table.
Claims20
A pre-distortion method for a radio that transmits a first band of a dual band signal at a first carrier frequency and transmits a second band of the dual band signal at a second carrier frequency, the method comprising:
- tuning a first signal s1 having first signal information to a first intermediate frequency to produce a first tuned signal, the first intermediate frequency being less than the first carrier frequency and less than the second carrier frequency;
- tuning a second signal s2 having second signal information to minus the first intermediate frequency to produce a second tuned signal;
- and
- pre-distorting a sum of the first tuned signal and the second tuned signal to produce a pre-distorted signal.
A method of pre-distorting a dual band signal to compensate for distortion of a power amplifier in a transmitter that transmits a first band of the dual band signal at a first carrier frequency and transmits a second band of the dual band signal at a second carrier frequency, the method comprising:
- tuning a first signal s1 having first signal information to a first intermediate frequency to produce a first tuned signal, the first intermediate frequency being less than the first carrier frequency and less than the second carrier frequency;
- tuning a second signal s2 having second signal information to a second intermediate frequency to produce a second tuned signal;
- adding the first signal to the second tuned signal to produce a third signal and adding the second signal to the first tuned signal to produce a fourth signal;
- inputting the third signal into a first pre-distorter applying a first set of basis functions to the third signal to produce a first pre-distorted signal having the first signal information at baseband;
- and
- inputting the fourth signal into a second pre-distorter applying the first set of basis functions to the fourth signal to produce a second pre-distorted signal having the second information signal at baseband.
A radio frequency, RF, transmitter, comprising:
- a first tuner tuning a first information signal s1 to a first intermediate frequency to produce a first tuned signal, the first intermediate frequency being less than a first carrier frequency at which the RF transmitter transmits the first information signal;
- a second tuner tuning a second information signal s2 to minus the first intermediate frequency to produce a second tuned signal, the first intermediate frequency also being less than a second carrier frequency at which the RF transmitter transmits the second information signal;
- and
- a pre-distorter applying a set of basis functions to pre-distort a sum of the first tuned signal and the second tuned signal according to a set of basis functions to produce a pre-distorted signal.
Dependencies are inferred from the claim text.