Abstract: Embodiments of a centralized predistortion system and corresponding adaptive predistortion processes are disclosed. In general, a central node includes one or more centralized predistortion components that enable predistortion for one or more remote transmit chains in order to compensate for non-linearity of power amplifiers in the one or more remote transmit chains. For instance, in one embodiment, the central node is a hub base station and the one or more remote transmit chains are included in one or more transmitters at one or more satellite base stations.

Abstract: Methods and circuits for pre-distorting a signal to compensate for distortion introduced by an electronic device operating on the signal. In an example method, first and second signal samples representing the input and output of the electronic device are generated. The first and second signal samples are spaced at unit-delay intervals, and each of the second signal samples corresponds in time to one of the first signal samples. Pre-distortion weights are then calculated from the first and second signal samples, the pre-distortion weights corresponding to a pre-distortion model comprising a lattice-predictor memory model structure having multiple delays and having at least one multi-unit delay interval between adjacent delays. The calculated pre-distortion weights are then applied to the input signal, using a predistorter with a structure corresponding to the lattice-predictor memory model, to produce a pre-distorted input signal for input to the electronic device.

Abstract: Digital predistorter circuits with selectable basis function configurations are described. In some embodiments, an input scaling block is introduced prior to a basis function generator structure. The input scaling factor is based on the input signal's average power. In other embodiments, configurable connection coefficients are used to construct the orthogonal basis functions. Multiple sets of tap weights for the predistorter are maintained, each set corresponding to a given basis function configuration. In an example method for pre-distorting an input signal to compensate for distortion introduced by an electronic device, a statistic characterizing the input signal is calculated, and one of a pre-determined set of basis function configurations is selected, based on the statistic.

Abstract: A distortion model for a predistortion system uses tap output normalization to normalize the variance of data signals generated from different basis functions in a set of basis functions to a predetermined value. The distortion model is used by a distortion modeling circuit to calculate the weighting coefficients for a digital predistorter.

Abstract: A predistorter applies a distortion function to an input signal to predistort the input signal. The output of the distortion function is modeled as the sum of the output signals from the orthogonal basis functions weighted by corresponding weighting coefficients. Techniques are described for orthogonalizing the basis function output signals depending on the distribution of the input signal.