PAPR Reduction Technique with PTS and Compander in OFDM System
- 발행기관 亞洲大學校 情報通信大學院
- 지도교수 盧炳希
- 발행년도 2005
- 학위수여년월 2005. 2
- 학위명 석사
- 학과 및 전공 정보통신대학원 정보통신
- 본문언어 영어
초록/요약
In recent years, the increasing demand for high data rate services necessitates the adoption of very wideband waveforms. Orthogonal Frequency Division Multiplexing (OFDM) is one of the technologies consist of multi-carrier communication scheme, in which the bandwidth of the channel is divided into a large number of sub-carriers and data symbols. This is also well-known to be effective against multi-path fading distortion. By inserting guard time that is longer than the delay spread of the channel, the OFDM system is able to mitigate Inter-Symbol Interference (ISI). Today, OFDM is mainly used in Wireless LAN (IEEE802.11a, HIPERLAN2), Digital Audio Broadcasting (DAB), Digital Video Broadcasting (DVB), and other high-speed data applications for both wireless and wired communications. One of the major drawbacks of the OFDM system is the high Peak to Average Power Ratio (PAPR). Due to the non-linearity of High Power Amplifier (HPA) of the transmitter, the high PAPR causes signal distortion in the non-linear HPA. The signal distortion induces the degradation of Bit Error Rate (BER). In this paper we propose a method to reduce the PAPR with Partial Transmit Sequences (PTS) and Companding technique.
more초록/요약
근년 multi-media 등 고속 data service 의 수요가 높아지며 통신의 강대역이 필요하게 되고 있다. Orthogonal Frequency Division Multiplexing (OFDM)은 많은 수의 부반송파와 data symbol 을 사용한 multi-carrier 통신 기술의 한 방법이다. 또한 multi-path fading distortion 에 관한 특징도 가지고 있다. OFDM system 은 channel 의 delay spread 보다 긴 guard time 를 삽입하여 Inter-Symbol Interference (ISI)의 영향을 줄일 수 있다. 최근 OFDM 은 주로 Wireless LAN (IEEE802.11a, HIPERLAN2), Digital Audio Broadcasting (DAB), Digital Video Broadcasting (DVB)과 가타 고속 data 통신이 필요한 무선/유선 통신의 application 으로 사용하고 있다. 한면 OFDM system 은 Peak to Average Power Ratio (PAPR)가 높은 문제점이 있다. 이것은 송신부에 가진 High Power Amplifier (HPA)의 비직선 특성 때문에 발생한 신호의 distortion 이다. 이 distortion 에 영향으로 system 의 Bit Error Rate (BER)가 높아진다. 이 논문에서는 Partial Transmit Sequences (PTS)과 Compander 을 사용하여 PAPR 을 줄이는 기법을 제안한다.
more목차
Contents
Abstract
Acknowledgements
Contents
List of Figures
1.Introduction = 1
(1) History of OFDM = 1
(2) Difference between FDM and OFDM = 2
(3) Generation of OFDM signal = 3
(4) Orthogonality = 5
(5) Scheme of OFDM transmitter and receiver = 7
2. PAPR and Non-linear devices = 10
(1) PAPR problem = 10
(2) Nonlinear distortion at Transmitter = 13
(3) Non-linear Power Amplifier Model = 14
3. Reduction techniques of PAPR in OFDM systems = 15
(1) Clipping and Filtering = 16
(2) Block Scaling = 18
4. Proposed Technique = 20
(1) Partial Transmit Sequences = 20
(2) Compander = 22
5. Simulation = 25
6. Simulation Results = 30
7. Conclusion = 33
8. References = 34
