This invention is about a DAPD-LUT technique of dynamically adapting an LUT spacing for linearizing a power amplifier (PA). It optimizes the LUT spacing for the PA without prior knowledge of system state information. A size-N LUT divides a whole unsaturated PA input amplitude range into N bins, each predistorted by an entry of the LUT. The LUT is indexed by an input amplitude of a modulated signal via an index mapper to implement an unconditionally non-uniform LUT spacing. A spacing adaptor online interactively adapts the LUT spacing. The adapted LUT spacing balances the IMD power at the PA output corresponding to each bin, so that the total IMD power at the PA output is minimized. This dynamically-optimum technique is practical, robust, and with low complexity.