| 000 | 00000nam c2200205 c 4500 | |
| 001 | 000045828207 | |
| 005 | 20230719091749 | |
| 007 | ta | |
| 008 | 150103s2015 ulkad bmAC 000c eng | |
| 040 | ▼a 211009 ▼c 211009 ▼d 211009 | |
| 085 | 0 | ▼a 0510 ▼2 KDCP |
| 090 | ▼a 0510 ▼b 6YD36 ▼c 279 | |
| 100 | 1 | ▼a 하영선 ▼g 河永善 |
| 245 | 1 0 | ▼a Channel estimation and ICI mitigation algorithms for OFDM systems / ▼d Young Sun Ha |
| 260 | ▼a Seoul : ▼b Graduate School, Korea University, ▼c 2015 | |
| 300 | ▼a vi, 84장 : ▼b 삽화, 도표 ; ▼c 26 cm | |
| 500 | ▼a 지도교수: 鄭原周 | |
| 500 | ▼a 부록수록 | |
| 502 | 1 | ▼a 學位論文(博士)-- ▼b 高麗大學校 大學院, ▼c 컴퓨터·電波通信工學科, ▼d 2015. 2 |
| 504 | ▼a 참고문헌: 장 78-83 | |
| 530 | ▼a PDF 파일로도 이용가능; ▼c Requires PDF file reader(application/pdf) | |
| 653 | ▼a OFDM ▼a Channel Estimation ▼a ICI | |
| 776 | 0 | ▼t Channel estimation and ICI mitigation algorithms for OFDM systems ▼w (DCOLL211009)000000057335 |
| 900 | 1 0 | ▼a Ha, Young-sun, ▼e 저 |
| 900 | 1 0 | ▼a 정원주, ▼g 鄭原周, ▼d 1966-, ▼e 지도교수 ▼0 AUTH(211009)153490 |
| 945 | ▼a KLPA |
Electronic Information
| No. | Title | Service |
|---|---|---|
| 1 | Channel estimation and ICI mitigation algorithms for OFDM systems (53회 열람) |
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Holdings Information
| No. | Location | Call Number | Accession No. | Availability | Due Date | Make a Reservation | Service |
|---|---|---|---|---|---|---|---|
| No. 1 | Location Science & Engineering Library/Stacks(Thesis)/ | Call Number 0510 6YD36 279 | Accession No. 123051163 | Availability Available | Due Date | Make a Reservation | Service |
Contents information
Abstract
The demands for communication systems to cope with high data rates have increased. Orthogonal frequency division multiplexing (OFDM) is a promising candidate due to its robustness against frequency selective fading. However, OFDM is known to be vulnerable to several impairments such as in-phase/quadrature (I/Q) mismatch, phase noise, and frequency offset which destroy orthogonality of subcarriers. This loss of orthogonality results in power leakage among subcarriers, known as inter-carrier interference (ICI), and makes accurate channel estimation to be a challenging problem in OFDM systems. Hence, to guarantee an reasonable quality of system performance for the presence of above impairments, sophisticated design of channel estimation and ICI mitigation is essential for OFDM systems. This thesis takes estimation and compensation techniques for these issues. In the first part of this thesis, using pilot subcarriers located asymmetrically, we develop a novel pilot scheme for the transmitter (Tx) IQ mismatch estimation. The pilot scheme exploits the conjugate redundancy of the subcarrier mirror images due to the Tx IQ mismatch and allows the estimation of the Tx IQ mismatch factor and channel parameter independently. In the second part of this thesis, we introduce two phase noise compensation schemes for frequency and time-domain approach, respectively. in frequency domain, with help from a blind adaptive phase offset recovery scheme called the dispersion minimization de-rotator, we investigate a phase noise suppression technique to mitigate the common phase error (CPE) due to the RF phase noise especially for high order QAM constellations. As a time-domain approach, by exploiting the redundancy of the cyclic prefix (CP), we have described a blind feedforward phase noise mitigation scheme. The proposed technique reduced both the CPE and ICI by using a linear approximation in the time domain. Finally, we introduce multipath channel estimation algorithms in the presence of mobility. The proposed method estimates channel parameters such as Doppler frequency and complex amplitude for individual channel paths in time-domain. By exploiting the reusable samples in the CP, our algorithm increases channel diversity and acquires those parameters with symbol-by-symbol processing.
Table of Contents
Contents Abstract Contents i List of Figures iv List of Tables vi 1 Introduction 1 1.1 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1.1 History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1.2 Issues of OFDM . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.2 Dissertation Outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2 OFDM Overview 7 2.1 Fundamental Design of OFDM . . . . . . . . . . . . . . . . . . . . . . 7 2.2 Guard Interval and Cyclic Extension . . . . . . . . . . . . . . . . . . . 9 2.3 The Choice of OFDM Parameters . . . . . . . . . . . . . . . . . . . . . 11 2.4 Basic OFDM System Model . . . . . . . . . . . . . . . . . . . . . . . . 12 3 Tx IQ mismatch Compensation for OFDM Systems 15 3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 3.2 The Signal Model For Tx IQ Mismatch . . . . . . . . . . . . . . . . . 17 3.3 The Proposed Pilot Structure . . . . . . . . . . . . . . . . . . . . . . . 19 3.3.1 The Pilot Tone Arrangement . . . . . . . . . . . . . . . . . . . 19 3.3.2 The channel and Tx IQ mismatch Estimation . . . . . . . . . . 20 3.3.3 The Analysis of Performance Improvement . . . . . . . . . . . 20 3.4 Numerical Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 3.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 4 Phase Noise Suppression for OFDM systems 26 4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 4.2 Frequency-domain Approach . . . . . . . . . . . . . . . . . . . . . . . 29 4.2.1 Common Phase Error Model . . . . . . . . . . . . . . . . . . . 29 4.2.2 Proposed Algorithm . . . . . . . . . . . . . . . . . . . . . . . . 31 4.2.3 Numerical Results . . . . . . . . . . . . . . . . . . . . . . . . . 35 4.3 Time-Domain Approach . . . . . . . . . . . . . . . . . . . . . . . . . . 41 4.3.1 System model . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 4.3.2 Proposed Algorithm . . . . . . . . . . . . . . . . . . . . . . . . 43 4.3.3 Numerical Results . . . . . . . . . . . . . . . . . . . . . . . . . 45 4.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 5 Time-varying Doppler Channel Estimation for OFDM Systems 48 5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 5.2 System Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 5.2.1 Mobile Multipath Channel . . . . . . . . . . . . . . . . . . . . 51 5.2.2 OFDM Signal Model . . . . . . . . . . . . . . . . . . . . . . . . 53 5.3 Problem Statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 5.4 Channel Parameters Estimation . . . . . . . . . . . . . . . . . . . . . . 56 5.4.1 Method 1 : Least Squares Fitting . . . . . . . . . . . . . . . . . 58 5.4.2 Method 2 : Deterministic Cost Function . . . . . . . . . . . . . 60 5.4.3 Method 3 : Linear Interpolation . . . . . . . . . . . . . . . . . 62 5.4.4 Complex Amplitudes Estimation . . . . . . . . . . . . . . . . . 63 5.5 Iterative Feedback Receiver . . . . . . . . . . . . . . . . . . . . . . . . 63 5.6 Complexity Reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 5.6.1 An Equivalent Manipulation for CP Recycling . . . . . . . . . 64 5.6.2 Channel Estimation . . . . . . . . . . . . . . . . . . . . . . . . 65 5.7 Numerical Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 5.8 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 Appendix A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 Appendix B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 Appendix C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 6 Conclusion 75 Bibliography 78 Acronyms 84
