Influence distortion of power amplifier on signals with orthogonal subband base

Author(s):  D.V. Ursol, candidate of Sciences, no, RV-SYSTEMS LLC, Moscow, Russia, ursol@rv-systems.ru

Issue:  Volume 47 № 1

Rubric:  Infocommunication technologies

Annotation:  The article discusses the orthogonal subband basis and the effect of nonlinearity of the power amplifier on the out-of-band emission level and character distortion at the receiving side after decoding. Described a method for generating and processing a channel signal using an orthogonal subband base. Computational experiments were performed with the parameters of the WiFi wireless standard and various levels of non-linear distortion of the power amplifier, including comparison with the orthogonal frequency division multiplexing (OFDM). The calculation results show the need to develop a digital predistortion of a subband orthogonal basis to compensate for the nonlinearity of amplifiers. Digital predistortion can be calculated for orthogonal basis previously and saved in memory before modulation with give less complexity and additional noise immunity on receiver side. The results show the same mean error vector magnitude between orthogonal subband basis and OFDM because they have same peak to average power ratio (PAPR) values about 10 dB.

Keywords:  power amplifier, nonlinearity, amplifier saturation, amplifier distortion, orthogonal frequency division multiplexing, orthogonal subband basis, quadrature modulation, error vector magnitude

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