한국정보통신학회논문지 (Journal of the Korea Institute of Information and Communication Engineering)

  • 제11권9호
  • /
  • Pages.1734-1741
  • /
  • 2007
  • /
  • 2234-4772(pISSN)
  • /
  • 2288-4165(eISSN)
한국정보통신학회 (The Korea Institute of Information and Commucation Engineering)
권호 표지
DOI QR코드

DOI QR Code

하이브리드 SC/MRC-2/4기법을 적용한 직교 MC DS-CDMA 시스템의 위상 에러에 관한 연구

A Study on Phase Error of Orthogonal MC DS-CDMA Using Hybrid SC/MRC-2/4

  • 김원섭 (청주대학교 전자정보공학부)
  • 발행 : 2007.09.29
PDF 다운로드
⟨ 이전 논문 다음 논문 ⟩

초록

본 논문에서는 정규화 된 부반송파 간격과 확산 이득이 동일하고 각 부반송파의 직접 확산 코드가 직교하도록 하는 직교 MC DS-CDMA 시스템에 비트 동기와 위상 동기가 요구되지 않는 Hybrid SC/MRC-2/4 방식을 적용하였다. 다중 반송파 전송이 사용되는 광대역 무선 시스템에서는 가장 높은 부반송파 주파수와 가장 낮은 부반송파 주파수 차이 때문에 발생하는 도플러 주파수 천이가 발생하고 이로 인한 위상 에러율 보상하기 위하여 전체 시스템에 맞는 PLL이득 값을 조절하여 완전 동기 된 수신 신호가 되도록 직교 MC DS-CDMA시스템을 분석하였다. 분석 결과, PLL이득 값을 증가시킴에 따라 완전 동기 된 경우에 근접함을 알 수 있지만 일정 값 이상에서는 그 간격의 변화가 매우 작아짐을 알 수 있다. 따라서 시스템에 맞는 적절한 PLL이득 값을 선택함으로써 Hybrid SC/MRC 방식이 적용된 직교 MC DS-CDMA시스템을 설계할 수 있을 것이다.

In this paper, the Hybrid SC/MRC-2/4 method in which bit synchronization and phase synchronization were not required was applied to the orthogonal MC DS-CDMA system in which each normalized subcarrier interval and processing gain had the same value, respectively, and the direct sequence spread code of each subcarrier was orthogonal. In the broadband wireless system in which multi-carrier transmission was used, a Doppler frequency shift occurred, which was caused by the difference between the highest subcarrier frequency md the lowest subcarrier frequency. In order to complement phase error caused by the shift, the orthogonal MC DS-CDMA system was analyzed so that the receiving signal could be perfectly synchronized by adjusting the PLL gain suitable for the entire system. As a result of simulations, as the PLL gain was increased, the change in the intervals was close to the case of perfect synchronization however, it became less when the PLL gain reached more than a certain value. Therefore, by selecting a proper PLL gain suitable for the system the orthogonal MC DS-CDMA can be designed in which the Hybrid SC/MRC method is applied.

키워드

참고문헌

  1. Lajos Hanzo et al., Single and Multi-Carrier DS-CDMA : Multi-User Detection, Space-Time Spreading, Synchronisation, Standards and Networking, IEEE Press-Wiley, June 2003
  2. R.Prasad and Hara, ' Overview of Multicarrier CDMA,' IEEE Commun. Mag., Dec. 1997, pp126-133
  3. Lie-Liang Yang and Lajos Hanzo, 'Multicarrier DS-CDMA :A Multiple Access Scheme for Ubiquitous Broadband Wireless Communications,' IEEE Commun, Mag., October. 2003, pp 116-124
  4. Shiro Kondo and Laurence B. Milstein, 'Performance of Multicarrier DS-CDMA Systems,' IEEE Trans. Commun., vol.44, No.2, pp. 238-246, Feb. 1996 https://doi.org/10.1109/26.486616
  5. Ana Garcia Annada, 'Understanding the Effeets of Phase Noise in OFDM,' IEEE Transactions on Broadcasting, Vol.47, No.2, June 2001, pp.153-159 https://doi.org/10.1109/11.948268
  6. E. A. Sourour and M. Nakagawa, 'Performance of Orthogonal Multicarrier CDMA in Multipath Fading Channel,' IEEE Trans. Commun., vol.44, Mar.1996, pp.356-367 https://doi.org/10.1109/26.486330
  7. John. G. Proakis, Digital Communications, 3rd ed. NewYork, McGraw-Hill, 1995
  8. Marvin K. Simo and Moharmed-Sim Aiouini, Digital Communication over Fading Channels, 1st ed. New York, John wiley & Sons, Inc., 2000
  9. Thomas Eng and Laurence B. Milstein, 'Partially Coherent DS-SS performance in Frequency Selective Multipath Fading,' IEEETrans. Commun., vol.45,No 1,pp. 110-118, Jan. 1997 https://doi.org/10.1109/26.554293
  10. William J. Weber, 'Performance of Phase-Locked Loops in the presence of Fading Communication Channels,' .IEEE Trans. Commun, vol.24, No.5, pp. 487-498, May1976 https://doi.org/10.1109/TCOM.1976.1093330
  11. Mohamed-Slim Alouini and Marvin K. Simon, ' Performance of Coherent Receivers with Hybrid SC/MRC over Nakagami-m Fading Channels,' IEEE Trans. Commun, vol.48,pp. 1155-1164, Aug. 1999