Journal of the Institute of Electronics Engineers of Korea TC (대한전자공학회논문지TC)

The Institute of Electronics and Information Engineers (대한전자공학회)
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Subcarrier-based Handover Scheme for Downlink OFDMA Cellular systems

하향링크 직교주파수분할다중접속 셀룰러 시스템을 위한 부반송파 기반 핸드오버 기법

  • Wang, Han-O (Dept. of Electrical and Electronic Engin., Yonsei University) ;
  • Lee, Sung-Eun (Dept. of Electrical and Electronic Engin., Yonsei University) ;
  • Hong, Dae-Sik (Dept. of Electrical and Electronic Engin., Yonsei University)
  • 왕한호 (연세대학교 전기전자공학부) ;
  • 이성은 (연세대학교 전기전자공학부) ;
  • 홍대식 (연세대학교 전기전자공학부)
  • Published : 2008.02.25
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Abstract

In this paper, a new subcarrier-based handover scheme which exploits different channel gains of subcarriers in downlink OFDMA cellular systems. In this handover scheme, mobile users can obtain diversity gain by subcarrier selection. Feedback for unselected subcarriers reduces interference. The capacity enhancement by the handover scheme is originated from the following two characteristics of OFDMA systems. One is that interference per subcarrier is proportional to the traffic load. The other is that every subcarrier has different channel gain ?? 새 the Rayleigh fading channel. Therefore, selecting subcarriers with stronger channel gains results in diversity gain. Simulation results confirm that the proposed handover scheme improves the capacity of the OFDMA systems by reducing 24 percentage of the outage probability.

본 논문에서는 직교주파수분할다중접속(Orthogonal Frequency Division Multiple Access) 하향링크 시스템에서 부반송파 별 채널 이득(channel gain)이 다름을 이용하여 시스템의 용량을 향상시킬 수 있는 핸드오버 기법을 제안한다. 제안하는 기법에서 핸드오버 중인 사용자는 소스 기지국(source base station)과 타겟 기지국(target base station)에서 할당 받은 부반송파 중 강한 채널이득을 가진 부반송파를 선택해 줌으로써 이득을 얻는다. 부반송파 선택 과정에서 탈락한 부반송파에 대한 정보는 기지국으로 피드백(feedback)되어 사용하지 않도록 하여 시스템 전체의 간섭(interference)량을 줄인다. 제안하는 기법은 핸드오버하고 있는 사용자의 오수신 확률을 22% 줄였으며, 이에 따라 시스템 전체의 전송률이 향상된다.

Keywords

References

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