Proceedings of the Korean Institute of Information and Commucation Sciences Conference (한국정보통신학회:학술대회논문집)

The Korea Institute of Information and Commucation Engineering (한국정보통신학회)
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A Study on Adaptive Sine Soft Clipping Method for PAPR Reduction in OFDM System

OFDM 시스템의 PAPR 감소를 위한 Adaptive Sine Soft Clipping 기법에 관한 연구

  • Yoo, Sun-Yong (Dept. of Inform. & Telecom. Eng., Graduate School of Korea Aerospace University) ;
  • Kim, Wan-Tae (Dept. of Inform. & Telecom. Eng., Graduate School of Korea Aerospace University) ;
  • Jo, Sung-Jun (Dept. of Inform. & Telecom. Eng., Graduate School of Korea Aerospace University)
  • 유선용 (한국항공대학교 대학원 정보통신공학과) ;
  • 김완태 (한국항공대학교 대학원 정보통신공학과) ;
  • 조성준 (한국항공대학교 대학원 정보통신공학과)
  • Published : 2007.10.26
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Abstract

OFDM (Orthogonal Frequency Division Multiplexing) system is robust to frequency selective fading and narrowband interference in high-speed data communications. However, an OFDM signal consists of a number of independently modulated subcarriers, which can give a large PAPR (peak-to-Average Power Ratio) when added up coherently. In this paper, we propose a new PAPR reduction method using Adaptive Sine Soft Clipping (ASS Clipping) to solve the PAPR problem. The proposed method reduce the PAPR and out-of-band spectrum by cutting down high frequency components. From computer simulation results, we analyze the PSD (Power Spectral Density) and BER (Bit Error Rate) performance as well as PAPR reduction performance when the ASS Clipping method is applied to OFDM system.

OFDM (Orthogonal Frequency Division Multiplexing) 방식은 주파수 선택적 페이딩 (frequency selective fading)과 협대역 간섭 (narrowband interference)에 강한 전송 방식으로 고속 데이터 통신에 적합하다. 하지만, OFDM 신호는 독립적으로 변조된 많은 부반송파들로 구성되므로 이들이 동위상으로 더해질 때 신호의 진폭이 증가하여 PAPR (Peak-to-Average Power Ratio) 문제가 발생한다. 본 논문에서는 OFDM의 PAPR 감소는 물론 고주파 성분 제어를 통하여 대역 외 스펙트럼 방출을 줄이고 clipping에 의한 왜곡을 감소시킬 수 있다. 시뮬레이션 과정을 통해 OFDM 시스템에 제안하는 알고리즘을 적용했을 경우, PAPR의 감소 정도와 PSD (Power Spectral Density), BER (Bit Error Rate)을 분석한다.

Keywords