The Journal of Korean Institute of Electromagnetic Engineering and Science (한국전자파학회논문지)

The Korean Institute of Electromagnetic Engineering and Science (한국전자파학회)
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A Simultaneous Compensation for the CPE and ICI in the OFDM System

OFDM 시스템에서 CPE와 ICI의 동시보상 방법

  • Li Ying-Shan (Dept. of Electronic Engineering and Research Institute of Computer, Information & Communication, Chungbuk National University) ;
  • Ryu Heung-Gyoon (Dept. of Electronic Engineering and Research Institute of Computer, Information & Communication, Chungbuk National University) ;
  • Jeong Young-Ho (Broadcasting System Department, Radio & Broadcasting Lab., ETRI) ;
  • Hahm Young-Kown (Broadcasting System Department, Radio & Broadcasting Lab., ETRI)
  • 이영선 (충북대학교 전자공학과 및 컴퓨터정보통신연구소) ;
  • 유흥균 (충북대학교 전자공학과 및 컴퓨터정보통신연구소) ;
  • 정영호 (한국전자통신연구원 전파방송연구소 이동멀티미디어방송연구팀) ;
  • 함영권 (한국전자통신연구원 전파방송연구소 이동멀티미디어방송연구팀)
  • Published : 2004.12.01
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Abstract

OFDM technique was adopted as the standard of IEEE 802.1 la and it has been widely used for wireless LAN, European DVB/DAB system, Korean DMB system. In the standard of IEEE 802.11a the data packet is composed of two parts, preamble and data. Preamble is composed of short pilots and long pilots, which are used for synchronization and estimation of frequency offset and channel. We can also compensate phase noise effect in the transceiver by using above pilots. The phase noise is more complicate than frequency offset and seriously affects system performance. In this paper, we newly propose CPE and ICI simultaneous compensation method to compensate phase noise generated by transceiver oscillator and compare with previous studies. As results, phase noise effect can be significantly compensated by CPE cancellation method, PNS algorithm and our proposed CPE and ICI compensation method. Especially, the proposed CPE and ICI compensation method can achieve the best BER performance compared with original OFDM, CPE cancellation method and PNS algorithm.

OFDM 기술은 채널의 시간확산에 대처할 수 있는 대역효율이 높은 전송방식으로서 IEEE 802.1 la 표준안으로 채택되어 고속 무선 랜, 유럽 DVB 등에 사용되고 있다. IEEE 802.113의 표준에서의 데이터 패킷은 프리앰블, 데이터 두 가지 부분으로 조성되고 있다. 프리앰블은 short pilots, long pilots로 조성되어 동기화, 주파수 옵셋 및 채널 추정에 사용되고 있다. 우리는 이러한 파일럿을 이용하여 송수신 과정에서 발생하는 위상잡음의 영향을 효과적으로 보상한다. 위상잡음은 주파수 옵셋보다 더 복잡한 현상으로서 시스템 성능에 매우 큰 영향을 준다. 본 연구에서는 위상잡음의 영향에 의해 발생하는 CPE와 ICI성분을 동시에 보상하는 새로운 방법을 제안하고 기존 연구와 비교 분석한다. 분석결과, CPE 제거기법, PNS 알고리즘, 그리고 CPE와 ICI 동시 보상기법을 사용하였을 경우, 위상잡음에 의한 성능 저하를 현저히 개선한다. 또한 제안한 CPE와 ICI 동시 보상기법을 사용한 경우 기존의 방법보다 더 우수한 통신성능을 얻을 수 있다.

Keywords

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