The subject of this paper is the compensation for nonlinearities in digital communication systems by means of predistortion. In this work, we apply the Generalized Cerebellar Model Articulation Controller (GCMAC) to simplify and accelerate the predistorter convergence. The range of analyzed predistorters includes: 1) a symbol-rate data predistorter that, for a given time span, achieves a simila...

Spectrally efficient linear modulation techniques are used in the third generation systems and their performance is strongly dependent on the linearity of the transmission system, Also, the efficiency of the amplifier to be used has to be maximized, which means that it must work near saturation. Newer transmission formats, with wide bandwidths, such as multi carrier wideband code division multi...

The linearization of RF power amplifiers (PA) can benefit from the availability of the generalized Volterra coefficients characterizing its non-linear response. In this work a large-signal network analyzer is used to acquire the amplitude and phase of the 3 intermodulation terms Ym3and Ym3+ of an LDMOSFET PA. The frequency dependence and difference between Ym3and Ym3+ reveals the memory effects...

Current wireless c o m m u n i c a t i o n standards have been established to carry voice, data and video with high data rates. These high data rates require efficient modulation techniques such as OFDM 64 QAM, to allow transmission in a given finite bandwidth. With these types of modulation, there are probabilities that at certain times, the voltages of the multiple carriers are in phase and t...

Co-design of digital signal-processing (DSP) algorithms and power-amplifier characteristics can lead to improved efficiency and linearity through a variety of strategies including: predistortion, DSP control over bias conditions, particularly the power supply voltage, and DSP generation of digital input signals for switching amplifiers. This paper discusses several amplifier architectures that ...

This paper describes the design and implementation of a memoryless digital predistortion (DPD) system for the linearization of power amplifiers. The system prototype predistorter requirements and architecture are implemented over a DSP-FPGA development kit. The design methodology is described in practical blocks and analyzed in detail with special emphasis in the digital domain, where the algor...

This application note describes system-level characterization and modeling techniques for radio frequency (RF) and microwave subsystem components. It illustrates their use in a mixed-signal, mixed-mode system-level simulation. The simulation uses an RF transmitter with digital predistortion (DPD) as an example system. Details of this complex system and performance data are presented. A similar ...

ACI = Adjacent Channel Interferences APSK = Amplitude Phase Shift Key BER = Bit Error Rate DPD = Digital Predistortion DTH = Direct To Home EQ = EQualization FIR = Finite Impulse Response GW = Gate Way HPA = High Power Amplifier IBO = Input Back-Off IMUX = Input ISI = Inter-Symbol Interference L-TWTA = Linearized Travelling Wave Tube Amplifier LS = Least Squares OBO = Output Back-Off OMUX = Out...

This work combines the advantages of two different RF power amplifier (PA) linearization techniques: digital predistortion (DPD) and Cartesian feedback (CFB). Cartesian feedback, an extension of classical continuoustime feedback, is limited by the bandwidth of its loop transfer function; this bandwidth, in turn, puts an upper limit on the bandwidth of the data input. However, this limitation gi...