Patent ID: 9191041
Filing Date: 2015-11-17
Classification: H03F,H04B

Abstract:
1. A method of generating digital pre-distorter, DPD, parameters, the method comprising iteratively updating parameters of a digital pre-distorter, DPD by: (a) generating a DPD output signal based on a modulated input signal, the DPD using a set of parameters; (b) converting the DPD output signal to an analog signal using a digital-to-analog converter operating at a rate of at least 5 times a Nyquist rate of the modulated input signal, the digital-to-analog converter producing an analog output signal; (c) amplifying the analog output signal via a power amplifier to produce a power amplifier output signal; (d) sampling the power amplifier output in a transmitter observation receiver, TOR, at a rate that is about 2 times the Nyquist rate of the modulated input signal to produce an observation signal; (e) generating a next set of parameters of the DPD via a DPD parameter determiner, the next set of parameters of the DPD derived from the observation signal and the DPD output signal; and (f) repeating steps (a) through (e) using the next set of parameters of step (e) in step (a) until a response of the power amplifier is linearized without substantial spectral regrowth throughout a frequency band defined by more than twice the bandwidth of the modulated input signal; a first set of parameters used in step (a) in a first iteration being based on a Volterra series pruned using G-functionals chosen to ultimately achieve substantial linearization of a response of the power amplifier over a number of iterations of steps (a) through (e) subject to a constraint that the power amplifier output is sampled in the TOR at a rate that does not exceed about 2 times the Nyquist rate of the modulated input signal.