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

The Institute of Electronics and Information Engineers (대한전자공학회)
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A Multicarrier CDMA System for Multipath and Doppler Diversity

다중경로 및 도플러 다이버시티를 위한 멀티캐리어 CDMA 시스템

  • Published : 2005.01.01
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Abstract

One of the principal disadvantages of multicarrier modulation technique is the sensitivity to the frequency offset introduced by Doppler shift. This frequency offset introduces inter-carrier interference (ICI) among the multiplicity of carriers in the multicarrier modulated signal. However, Doppler spread induced by temporal channel variations can Provide another means for diversity. In this paper, we propose a modified multicarrier code division multiple access (CDMA) system to exploit Doppler diversity as well as multipath diversity. The key work of our framework is a canonical time-frequency-based decomposition of the mobile wireless channel into series of independent fading channel. The decomposition naturally leads to a time-frequency generalization of the Rake receiver that exploits both multipath and Doppler diversity.

다중반송파 변조방식의 주요한 문제점중의 하나는 도플러 천이에 의한 주파수 옵셋에 민감하다는 점이다. 주파수 옵셋은 다중반송파 변조된 신호의 주파수 중첩으로 인한 반송파간의 간섭을 야기시킨다. 그러나 채널변화에 따른 도플러 천이는 또 다른 다이버시티 이득을 제공할 수 있는 요소가 될 수 있다. 본 논문에서는 변형된 다중반송파 코드분할 다중접속(multicarrier CDMA) 시스템을 제안함으로써 다중경로 다이버시티외에 도플러 다이버시티를 이용할 수 있게 하였다. 이를 위하여 이동 무선채널을 독립적인 시간 및 주파수 페이딩 채널로 분해하고 시간 다이버시티를 이용하는 레이크 수신기를 주파수영역으로 확장하므로써 다중경로 및 도플러 다이버시티 이득을 동시에 얻을 수 있도록 하였다.

Keywords

References

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