Compensation of the Nonlinear Power Amplifier by Using SCPWL Predistorter with Genetic Algorithm in OFDM technique

Abstract

The High Power Amplifiers (HPAs), which are used in wireless communication, are distinctly characterized by nonlinear properties. The linearity of the HPA can be accomplished by retreating an HPA to put it in a linear region on account of power performance loss. Meanwhile the Orthogonal Frequency Division Multiplex signal is very rough. Therefore, it will be required a large undo to the linear action area that leads to a vital loss in power efficiency. Thereby, back-off is not a positive solution. A Simplicial Canonical Piecewise-Linear (SCPWL) model based digital predistorters are widely employed to compensating the nonlinear distortion that introduced by a HPA component in OFDM technology. In this paper, the genetic algorithm has been used to optimized the SCPWL coefficients by using Matlab 2015b, and then the Bit Error Rate (BER) performance has been evaluated for OFDM signal with 16-QAM and 64-QAM modulations in three cases, with nonlinear effects, without nonlinear effects (ideal case), with SCPWL and with nonlinear effects (compensated case)). The simulation results showed that the predistorter that adjusted by the genetic algorithm accomplishes huge execution change by successfully compensating the nonlinearity and reducing the input and output back-off (IBO, OBO) of the HPA.

Channel estimation of OFDM in C-band communication systems under different distribution conditions

“…In the OFDMA framework, numerous symmetrical sub-carrier signals are firmly dispersed and covered for transmission of data. These symmetrical subs-carrier don't meddle with one another and give roughness to the inter-symbol interference and blurring of the channel (ISI) [1], [7]. The input information to be transmitted is first conveyed by the sub-carrier signals toss the balancing procedure which utilized here 64-PSK at the low image rate.…”

“…The expanding necessity for high-piece rate advanced versatile interchanges has impelled the presence of orthogonal frequency-division multiplexing (OFDM) for accomplishing great execution at a high pace of information transmission. In different correspondence frameworks for transmission of information, the orthogonal frequency division multiple access is a various access plans are chosen as a physical layer interface for cutting edge remote correspondence frameworks like IEEE [1]. OFDM is a transmission strategy that utilized numerous bearers in the symmetrical structure to transmit the back rubs all the while [2].…”