| Code division multiple access (CDMA) and orthogonal frequency division multiplexing (OFDM) signaling schemes are widely used nowadays in wireless communication systems. They are particularly suited for the increased and continuous demands of more capacity, higher data rates, better quality of service, and robustness against multipath fading. Unfortunately, such signals exhibit large dynamic ranges, as a result, they are more susceptible to amplifier nonlinearity. The distortion caused by nonlinearities leads to bit error rate (BER) degradation and out-of-band spectral regrowth.;Numerical experiments are performed to confirm the theoretical analyses and show the performance improvement of the developed measure in terms of an improved BER and reduced spectral regrowth.;In this dissertation, the nonlinear distortion effects due to power amplifiers are analyzed. In particular, we are interested in analytically quantifying the signal's nonlinear behavior in relation to the amplifier characteristics. Through analyses, the characteristics of the input signal to the amplifier that contribute to BER degradation and spectral regrowth are explored. Based on such characteristics, a new measure characterizing the nonlinear distortion is formulated. With this formulation, an efficient system in presence of nonlinear distortion can be achieved by redirecting attention to the signal at the input of the amplifier. Specifically, we investigate methods to: (1) provide a potential estimate of the nonlinear distortion effects on the system performance and (2) minimize such effects by minimizing the signal characteristics contributing to performance degradation. |
