Reduction of adjacent channel interference using postdistortion

An adaptive postdistortion approach that allows for an increase in spectral-efficiency and the portable transmitter power efficiency is presented. The basic idea of the postdistortion technique is to compensate for the adjacent channel's power amplifier AM-AM and AM-FM nonlinearities, at the base station receiver. Coupled with adaption algorithms, the receiver can compensate for slow variations in power amplifier characteristics, where adjacent channel interference is created by power amplifier nonlinearities. Simulation results demonstrate that the postdistortion technique can make an improvement in out-of-band emission by up to 15 dB; the corresponding increase in transmitter power efficiency is approximately a factor of five.<
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