Linerization of RF-power amplifiers by using memory polynomial digital predistortion technique

Download

index.pdf

Date

2012

Author

Erdoğdu, Gözde

Metadata

Show full item record

Item Usage Stats

191
views

174
downloads

In modern wireless communication systems, new modulation types are introduced in order to support more users by considering spectral efficiency. These new signals are ensitive to nonlinearity when they have high peak to average ratio. The main part in the system that causes nonlinearity is the power amplifier. For power amplifiers, between linearity and efficiency, there is a trade-off. However, by using predistortion techniques, both linearity and efficiency can be obtained. In this thesis, various predistortion methods are explained and memory polynomial digital predistortion is studied because of its great advantages. The results are obtained by simulations through MATLAB and experiments. An open loop test bench is built up with real amplifier. During experimental procedure, as input two tone signal, 8psk modulated signal and pi/2 bpsk modulated signal are used. Predistortion with memory and memoryless predistortion performances are compared and superiority of the predistortion with memory is shown. Predistortion performance with respect to memory depth and polynomial order is also studied. Moreover, predistortion model range is investigated through evaluation of performance by applying predistorter function estimated at a specific bandwidth and power to other signals having different bandwidth and power. Besides these works, the details of predistortion algorithm and the problems that can be countered in practice are explained.

Subject Keywords

Wireless communication systems., Wireless LANs., Power amplifiers., Polynomials.

URI

http://etd.lib.metu.edu.tr/upload/12614420/index.pdf
https://hdl.handle.net/11511/21616

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Design amd implementation of a VHF/UHF front-end using tunable dual band filters Alaca, Fatih; Yıldırım, Nevzat; Department of Electrical and Electronics Engineering (2012) For the new generation wireless communication systems, there is an increasing demand for devices that covers more than one frequency band. This results in a need for wide-band tunable front-ends. The main objective of this study is to use dual band filters in the design of a multi-band front-end. A wide-band low noise amplifier is also required. To accomplish this project, a fixed frequency bandstop filter, a tunable dual-band filter and a wide-band LNA are designed and implemented successfully. The predefi...
Broadband microwave diode mixer design and implementation Koç, Emrah; Demir, Şimşek; Department of Electrical and Electronics Engineering (2016) Mixers play a critical role in design and development of wireless communication systems. Demanding requirements of the mixers are improvements in conversion efficiency, bandwidth, cost, and linearity. Schottky barrier diodes attract mixer designers due to their favorable characteristics leading to wide bandwidth, low-cost, and high efficient designs. This thesis demonstrates the design and implementation of two passive mixing circuits using Schottky barrier diodes at microwave frequencies. The first circuit...
Blind channel estimation based on the Lloyd-Max algorithm innarrowband fading channels and jamming Dizdar, Onur; Yılmaz, Ali Özgür; Department of Electrical and Electronics Engineering (2011) In wireless communications, knowledge of the channel coefficients is required for coherent demodulation. In this thesis, a blind channel estimation method based on the Lloyd-Max algorithm is proposed for single-tap fading channels. The algorithm estimates the constellation points for the received signal using an iterative least squares approach. The algorithm is investigated for fast-frequency hopping systems with small block lengths and operating under partial-band and partial-time jamming for both detecti...
Improving the efficiency of microwave power amplifiers without linearity degradation using load and bias tuning in a new configuration Ronaghzadeh, Amin; Demir, Şimşek; Department of Electrical and Electronics Engineering (2013) Advanced digital modulation schemes used in the wireless applications, result in the modulated RF signals with high peak to average power ratio which requires linear amplification. On the other hand, the demand for a longer talk time with less battery volume and weight, especially in hand-held radio units, necessitate more power efficient methods to be utilized in power amplifier design. But improved linearity and efficiency have always been contradicting requirements demanding innovative power ampliﬁer and...
Linearization of RF power amplifiers with memoryless baseband predistortion method Kolcuoğlu, Turusan; Demir, Şimşek; Department of Electrical and Electronics Engineering (2011) In modern wireless communication systems, advanced modulation techniques are used to support more users by handling high data rates and to increase the utilization efficiency of the limited RF spectrum. These techniques are sensitive to the nonlinear distortions due to their high peak to average power ratios. Main source of nonlinear distortion in transmitter topologies are power amplifiers that determine the overall efficiency and linearity of the transmitter. To increase linearity without sacrificing effi...

Citation Formats

G. Erdoğdu, “Linerization of RF-power amplifiers by using memory polynomial digital predistortion technique,” M.S. - Master of Science, Middle East Technical University, 2012.