ŞEHİR e-arşiv

Performance evaluation of filtered orthogonal frequency division multiplexing (F-OFDM) in the presence of nonlinear power amplifier

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dc.contributor.advisor Özdemir, Mehmet Kemal
dc.contributor.author Moe Thet, Nann Win
dc.date.accessioned 2018-03-28T10:27:54Z
dc.date.available 2018-03-28T10:27:54Z
dc.date.issued 2018-03-28
dc.date.submitted 2017-09-06
dc.identifier.uri http://hdl.handle.net/11498/51656
dc.description Tezin basılısı İstanbul Şehir Üniversitesi Kütüphanesi'ndedir. en_US
dc.description.abstract Orthogonal Frequency Division Multiplexing (OFDM) has been a reliable modulation technique in 4G due to its ability to combat the intersymbol interference (ISI) caused by multipath channel and its efficient usage of spectrum due to orthogonality properties. However, OFDM as is faces challenges when it comes to supporting 5G applications requirements due to its high peak to average ratio (PAPR) and inability to provide asynchronous transmission. Therefore, filtered-OFDM (F-OFDM), which is the modified version of OFDM that separates the total assigned bandwidth into many sub-bands and then filtering each sub-band with an appropriate designed filter, was proposed in recent years. Many studies have been focusing on the performance of a F-OFDM system alone without taking the effect of power amplifier (PA) into account in the system. Therefore, in this thesis, we evaluate the performance of point-to-point F-OFDM system in the presence of nonlinear PA and also employ techniques used in OFDM system to reduce the effect of the PA. In this regard, we first simulate a basic F-OFDM system without a PA by using filters obtained from different filtering methods such as window based filter and Parks-McClellan filter. Specifically, the performance analysis is done in terms of power spectral density (PSD) and bit error rate (BER). Secondly, the performance of F-OFDM system with a nonlinear PA is analyzed, and it is observed that the out-ofband (OOB) emission is increased as expected. Hence, pre-distortion is also included in the system to linearize the response of the PA. From the simulation results, it is seen that OOB spectrum regrowth due to the PA is suppressed fully, yet it does not reach to the original OOB emission level. Lastly, a modified version of optimized iterative clipping and filtering (ICF) is introduced to optimize the high PAPR of the f-OFDM signal. With the optimized ICF method, the PAPR is greatly reduced, resulting in lower OOB emission. With the combination of optimized ICF and pre-distortion, the overall performance of F-OFDM system in the presence of nonlinear PA is improved compared to the system without a pre-distorter. en_US
dc.description.tableofcontents Abstract iv Öz v Acknowledgments vii List of Figures x Abbreviations xii 1 Introduction and Motivation 1 1.1 Evolution of Wireless Communications . . . . . . . . . . . . . . . . . . . . 1 1.2 F-OFDM as a waveform Candidate for 5G . . . . . . . . . . . . . . . . . . 5 1.3 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.4 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2 Literature Review 9 2.1 Literature Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.2 Thesis Contributions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 3 Performance Analysis of F-OFDM using Parks-McClellan Filter 16 3.1 F-OFDM Basis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 3.1.1 Conventional OFDM Transceiver . . . . . . . . . . . . . . . . . . . 16 3.1.2 F-OFDM Transceiver . . . . . . . . . . . . . . . . . . . . . . . . . 18 3.2 Filter Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 3.2.1 Window-based FIR Filter . . . . . . . . . . . . . . . . . . . . . . . 20 3.2.2 Parks-McClellan FIR Filter . . . . . . . . . . . . . . . . . . . . . . 26 3.3 Simulation and Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 3.4 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 4 F-OFDM system with Pre-Distorter 37 4.1 Effect of HPA on F-OFDM signal . . . . . . . . . . . . . . . . . . . . . . . 37 4.2 Implementing Digital Pre-Distortion . . . . . . . . . . . . . . . . . . . . . 41 4.2.1 Indirect Learning Architecture . . . . . . . . . . . . . . . . . . . . 41 4.2.2 Coefficient Estimation of Memory Polynomial (MP) Pre-Distorter . 43 4.2.3 Normalization Gain . . . . . . . . . . . . . . . . . . . . . . . . . . 44 4.3 Simulation and Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 4.4 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 5 F-OFDM system with Optimized ICF and Pre-Distorter 50 5.1 F-OFDM System with the Optimized ICF . . . . . . . . . . . . . . . . . . 50 5.1.1 Conventional Iterative Clipping and Filtering . . . . . . . . . . . . 51 5.1.2 Optimized Iterative Clipping and Filtering . . . . . . . . . . . . . . 51 5.2 Simulation and Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 5.2.1 F-OFDM System with the modified Optimized ICF . . . . . . . . . 53 5.2.2 F-OFDM System with both the Pre-Distorter and the Optimized ICF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 5.3 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 6 Conclusion 62 6.1 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 6.2 Future Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 Bibliography 65 en_US
dc.language.iso eng en_US
dc.rights info:eu-repo/semantics/embargoedAccess en_US
dc.subject Amplifiers (Electronics)--Design and Construction en_US
dc.subject Optimization en_US
dc.subject Amplifikatörler (Elektronik)--Tasarım ve Yapı en_US
dc.subject Optimizasyon en_US
dc.title Performance evaluation of filtered orthogonal frequency division multiplexing (F-OFDM) in the presence of nonlinear power amplifier en_US
dc.type Thesis en_US
dc.contributor.department İstanbul Şehir University. College of Engineering and Natural Sciences. Electronics and Computer Engineering. en_US


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