가중된 위상 부반송파를 이용한 새로운 병렬 결합 OFDM 시스템

Title
가중된 위상 부반송파를 이용한 새로운 병렬 결합 OFDM 시스템
Authors
장휴이
Keywords
가중된위상부반송파를이용한새로운병렬결합ofdm시스템
Issue Date
2011
Publisher
인하대학교
Abstract
Among all the existing peak-to-average power ratio (PAPR) reduction techniques in Orthogonal Frequency Division Multiplexing (OFDM) systems, partial transmit sequence (PTS) and selective mapping (SLM) schemes, where side information (SI) are introduced to rotate the transmitting symbol sequence, attract the most attentions. However, PTS-OFDM and SLM-OFDM both do not significantly improve the bit error rate (BER) performance. Parallel combinatory (PC) OFDM yields higher spectral efficiency (SE) and better BER performance on Gaussian channels, little but not obvious PAPR improvement compared to the ordinary OFDM system. In this paper, in order to design a ‘perfect’ OFDM system, by introducing side information to the proposed PC-OFDM system structure, we carefully design a novel side information based PC-OFDM system using maximum likelihood (ML) detector at the receiver, we call this new system as SIPC-OFDM system. The proposed system achieves better PAPR and BER performance. In addition, due to the parallel combinatory system structure, the proposed system also has the properties of higher spectral efficiency.
Description
Chapter 1 Introduction . 1 1.1 Motivation . 1 1.2 Objective . 2 Chapter 2 PAPR Reduction 5 2.1 OFDM system . 5 2.2 Mathematical definition of PAPR 6 2.2.1 OFDM signal . 6 2.2.2 PAPR definition . 7 2.3 Comparison of PAPR reduction techniques 8 2.4 Influence of phase sequence distribution on PAPR . 9 Chapter 3 Parallel Combinatory Technology . 13 3.1 APSK modulation 14 3.2 Parallel Combinatory Code . 14 3.3 Subcarrier Combinatory 15 3.3.1 Johnson association mapping model 16 3.3.2 Improved mapping model 18 3.4 Conventional PC-OFDM system . 21 Chapter 4 SIPC OFDM system with Weighted Subcarriers . 25 4.1 Proposed SIPC-OFDM system description . 25 4.2 Side information decoding process . 29 4.3 Receiver of SIPC-OFDM system 30 Chapter 5 Evaluation of Proposed Algorithm 35 5.1 Improving Spectrum Efficiency by Proposed System . 35 5.2 Improving power efficiency by PAPR reduction . 39 5.3 BER performance analysis 42 Chapter 6 Conclusion . 47 Reference 48 Acknowledgement 51 List of Figures Figure 1. Block diagram of an OFDM transmitter . 6 Figure 2.The uniformity of the weighted phase sequence when the phase factor number is 4 in PTS proposal, subcarrier number is 256, and adjacent partition into 4 clusters . 10 Figure 3. CCDF distribution curves of different side information distributions in the PTS proposal for adjacent partition . 11 Figure 4. CCDF distribution curves with different number of sub-block under adjacent partition:(1) K=2;(2) K=4; (3) K=8; in PTS proposal 11 Figure 5. The constellation diagram of (M+1)-ary APSK 14 Figure 6. Diagrammatic sketch of the mapping relationship between bits and subcarriers 17 Figure 7. Improved Diagrammatic sketch of the mapping relationship between bits and subcarriers . 20 Figure 8. The block diagram of conventional PC- OFDM system . 21 Figure 9. BER performance of PC-OFDM system with BPSK modulation 22 Figure 10. BER performance of PC-OFDM system with QPSK modulation 23 Figure 11. Spectral ef
URI
http://dspace.inha.ac.kr/handle/10505/22327
Appears in Collections:
College of Engineering(공과대학) > Graduate School of IT & Telecommunications (정보통신대학원) > Theses(정보통신대학원 석박사 학위논문)
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