Nonlinear amplification of CDMA waveforms: an analysis of power amplifier gain errors and spectral regrowth

The effect of nonlinear amplification on CDMA waveforms is investigated. Variations in the gain of the power amplifier (PA) in response to changes in the input power are used as a measure of the nonlinearity. The relationship between Walsh code selection, data sequences, PN sequences, and the wave-shaping filter in the generation of PA gain errors is discussed. An approach for reducing spectral regrowth by introducing correlations between data sequences within different Walsh code channels is proposed.