controller 101 the present invention is sometimes referred to as a remote radio head unit rru hereinafter fig2 illustrates in schematic block diagram form an embodiment of an eight channel or n channel rru in which an input signal 200 is provided depending on the implementation the input signal can take the form of an rf modulated signal a baseband signal or an optical signal the input signal 200 is fed to a plurality of channels where each channel includes a digital predistortion dpd controller indicated at 201 211 and 271 respectively the dpd can be implemented in an fpga in at least some embodiments for each channel the dpd outputs are fed to associated pa 39 s 202 212 and 272 respectively and the pa outputs 203 213 and 273 are fed back to that channel 39 s dpd 39 s fig3 illustrates a polynomial based digital predistorter function in the rru system of the present invention the pd in the present invention generally utilizes an adaptive lut based digital predistortion system more specifically the pd illustrated in fig3 and in embodiments disclosed from fig9 12 discussed hereinafter are processed in the digital processor by an adaptive algorithm presented in u s patent application ser no 11 961 969 entitled a method for baseband predistortion linearization in multi channel wideband communication systems the pd for the rru system in fig3 has multiple finite impulse response fir filters that is fir1 301 fir2 303 fir3 305 and fir4 307 the pd also contains the third order product generation block 302 the fifth order product generation block 304 and the seventh order product generation block 306 the output signals from fir filters are combined in.