The Journal of Korean Institute of Communications and Information Sciences (한국통신학회논문지)

The Korean Institute of Commucations and Information Sciences (한국통신학회)
권호 표지

A Study on the New Code Grouping Interference Cancellation for WCDMA Systems

WCDMA 시스템을 위한 새로운 코드 그룹화 간섭제거기

  • 김남선 (대진대학교 통신공학과)
  • Published : 2008.01.31
Download PDF
⟨ Previous Next ⟩

Abstract

In this paper, we propose a new code grouping interference cancellation(IC) receiver for multirate wideband code division multiple access(WCDMA) system based on orthogonal variable spreading factor(OVSF) code. The users are assigned different lengths of OVSF codes as a spreading code according to their data rates and divide the active users having same representative code split into a group for effective cancellation. The code grouping IC receiver performs cancellation between the groups first and cancellation within group. This proposed IC receiver can cancel the interferences using desired user's code information and then desired signals are detected. The results show that the large improvement in performance can be attained by groupwise IC scheme and we can make the effective systems compare to conventional ones.

본 연구에서는 다중 전송률을 갖는 WCDMA 시스템에서 OVSF코드를 사용한 새로운 코드 그룹화 간섭제거기를 제안한다. 사용자들은 전송률에 따라 길이가 다른 OVSF 코드를 할당하며 대표코드가 같은 OVSF 코드를 사용하는 사용자들을 그룹화 한다. 제안된 코드그룹화 간섭제거기는 그룹간 간섭을 제거한 후 그룹내 간섭을 차례로 제거한다. 간섭제거기는 간섭사용자들의 정확한 정보 없이 원하는 사용자의 코드 정보만 알고 있어도 간섭제거 및 사용자신호의 검출이 가능하다. 제안된 시스템은 그룹 단위의 처리를 통하여 간섭을 보다 쉽고 간단하게 제거함으로써 성능이 향상되며 기존 방식보다 효율적인 시스템을 구현할 수 있다.

Keywords

References

  1. E. Dahlman, et al.,"UNTS/IMT-2000 based on wideband CDMA," IEEE Commum. Mag., vol. 36, pp. 70-80, Sept. 1998
  2. T. Ottoson and A. Svensson, "Multi-rate Schemes in DS/CDMA Systems," Proceedings IEEE VTC'95, Chicago, pp. 1006-1010, July 1995
  3. A. Baier, et al., "Design Study of a CDMA-based Third Generation Mobile Radio System," IEEE J. Sel. Area Commun., vol. SAC-12, pp. 733-743, May 1994
  4. Ariyavisitakul and Li. Fing. Chang, "Signal and Interfernce Statistics of a CDMA System with Feedback Power Control," IEEE Trans. Commun., vol. 41, Issue 11, pp. 1626-1634, Nov. 1993 https://doi.org/10.1109/26.241743
  5. M. Juntti and M. Latva-aho, "Multiuser Receivers for CDMA Systems in Rayleigh Fading Channels," IEEE Trans. on Vehicular Technology, Vol. 49, No. 3, pp.885-899, May 2000 https://doi.org/10.1109/25.845107
  6. C.S. Wijting, T. Ojanpera, M. Juntti, K. Kansanen and R. Prasad, "Groupwise serial multiuser detectors for multirate DS-CDMA," VTC '99, Vol. 1, pp. 836-840, May 1999
  7. M. Madkour et al.,"Successive Interference Cancellation Algorithm for downlink W-CDMA Communications," IEEE Teans. on Commun., Vol. 1, No. 1, pp. 169-177, Jan. 2002
  8. W. Ha, J. Bae and J. Park,"A Code Grouping Interference Cancellation Receiver in OVSF DS-CDMA Downlink," The 8th ICCS 2002, pp.697-700, 2002
  9. F. Adachi, et al., "Tree-structured generation of orthogonal spreading codes with different lengths for forward link of DS-CDMA mobile radio," Electron Lett., vol. 33, pp. 27-27, Jan. 1997 https://doi.org/10.1049/el:19970022
  10. Gao Xue and Li Chengshu, "Performance of Partial Interference Cancellation in DS-CDMA System with Delay Estimation Errors," PIMRC 2000, Vol. 2, pp.1518-1521, Aug. 2000