On compensating nonlinear distortions of an OFDM system using an efficientadaptive predistorter

This paper presents an efficient adaptive predistortion technique compensat ing for nonlinear distortions caused by a high-power amplifier (HPA) cascad ed with a linear filter in an OFDM system, In the proposed approach, the me moryless HPA, preceded by a linear filter with memory in OFDM systems, is m odeled by the Wiener system, which is then precompensated by the proposed a daptive predistorter with a minimum number of filter taps. It is confirmed by computer simulation that the proposed approach produces a faster converg ence speed than the previous adaptive predistortion technique, and provides a small output backoff as low as 5.5 dB for an OFDM system employing an HP A with a linear filter.