Modern digital communication systems utilize OFDM and DS-CDMA signals because of their superior spectral efficiency and multiple access properties respectively. Examples of such systems include digital television (DVB-T), digital radio (DAB) and 3 Generation mobile (WCDMA). A downside to using these signals however is the need to accommodate their very high Crest Factor, also known as Peak-to-A...

In this paper we present a summary of nonlinear system level problems in beamforming. The paper summarizes first the nonideal phenomena in power amplifiers, mixers, and oscillators. In digital predistortion inversion of the nonlinearity is needed. Not all linear and nonlinear systems are invertible or they may have only a preinverse or postinverse. Commutation is needed in indirect learning arc...

This paper deals with digital base band signal processing algorithms, which are seen as enabling technologies for software-enabled radios, that are intended for the correction of the analog front end. In particular, this paper focuses on the design, optimization and testability of predistortion functions suitable for the linearization of narrowband and wideband transmitters developed with a hyb...

Predistortion in GSM has been introduced to deal with saturation in amplification at Base Transceiver Stations (BTS). This paper will focus on the elements and architectures in signal predistortion for one carrier and multicarrier modulations. The GCMAC neural network has been introduced as predistorter to provide the design with adaptive, digital and practical features. Some results are includ...

power amplifiers (pas) are inherently nonlinear elements and digital predistortion is a highly cost-effective approach to linearize them. although most existing architectures assume that the pa has a memoryless nonlinearity, memory effects of the pas in many applications ,such as wideband code-division multiple access (wcdma) or orthogonal frequency-division multiplexing (ofdm), can no longer b...

Intersymbol-interpolated digital data predistortion is an efficient countermeasure technique against the high-power amplifier non-linearity in digital microwave radio systems employing bandwidth-efficient quadrature amplitude modulation. This concept was recently introduced by the present authors using a specific transmit pulse shaping that leads to discrete signal levels at two or three points...

Digital predistortion of nonlinear systems is an important topic in many practical applications. This paper considers direct predistortion of a Volterra system by connecting in tandem an adaptive Volterra predistorter. The coefficients of the predistorter can be recursively estimated using the nonlinear filtered-x least mean squares (NFxLMS) algorithm. In this paper, the prediction error method...

This paper is focusing on the nondesirable nonlinear effects of power amplifiers for wireless communication. One of the most-used methods for amplifier nonlinearities reducing – digital baseband adaptive predistortion is presented.

This article presents a method for power amplifier linearization known as baseband adaptive digital predistortion. Using an EDA software package with both DSP (Digital Signal Processing) and RF capabilities, connected to a vector signal generator and a signal analyzer, this hardware/software connected system allows an actual hardware power amplifier to be optimally linearized for a specific wir...