Performance Analysis of a Cascaded Interference Canceller using Dead Zone Decision for DS/CDMA System

DS/CDMA 시스템에서 Dead Zone 검출방식을 이용한 직렬 간섭제거의 성능분석

  • Lee, Sang-Hun (Agency for Defense Development) ;
  • Kim, Nam (Division of Electrical and Electronic Eng., Chungbuk National Univ.)
  • 이상훈 (국방과학연구소) ;
  • 김남 (충북대학교 전기전자공학부)
  • Published : 2000.08.01

Abstract

In this paper, the cascaded co-channel interference canceller using the dead zone decision is proposed to reduced the co-channel interference in the DS/CDMA communication with the multipath fading and its performance is analyzed. The cancellation scheme creates the replica of the co-channel interference using the data decision of correlator output and removes it at the next stage. The canceller uses the dead zone decision which is detecting strong signal to obtain a good performance in the mobile communication. The results of performance analysis show that the proposed cancellation scheme has the improved performance and the number of user is increased 4 times compared with the conventional receiver, and increased 17% compared with the hard decision. And also the perfect power control is required along with increasing the number of user.

본 논문에서는 다중경로 패이딩 환경의 DS/CDMA 통신방식에서 성능저하 원인인 동일채널 간섭을 제거하기 위하여 dead zone 검출방식을 이용한 직렬 간섭제거기를 제안하고, 그 성능을 분석하였다. 직렬 간섭제거는 수신기 correlator 출력에서 검출한 데이터를 이용하여 동일채널 간섭을 재생한 후 다음 단계에서 제거해주는 방식이다. Dead zone 검출 방식은 이동통신 환경에서 동일채널 간섭의 제거 성능을 향상시키기 위해 비교적 강한 신호를 검출 방식으로써 제안한 직렬 간섭제거기의 성능분석 결과, 기존 수신기에 비해 동일채널의 사용자수가 약 4배 정도 증가하였으며, 제안한 dead zone 검출방식이 hard 검출방식에 비해 약 17% 정도 사용가 수의 증가하는 개선된 결과를 얻었다. 또한 원근문제에 있어서 사용자수 증가에 따라서 안정적인 전력제어가 필요함을 알수 있었다.

Keywords

References

  1. IEEE J-SAC v.8 An adaptive canceller of co-channel interference for spread spectrum multiple access communication networks in a power line R. Kohno;H. Imai;M. Harori;S. Pasupathy
  2. IEEE Trans. Comm. v.38 Near-far resistance of multiuser detection in asynchronous channels R. Lupas;S. Verdu
  3. IEEE Comm., Magazine Multi-user detection for DS-CDMA communications Shimon Moshavi
  4. IEEE J-SAC v.8 no.4 A family of suboptimum Detectors for coherent multi-user communication Z. Xie;R. T. Short;C. K. Rushforth
  5. IEEE 3rd ISSSTA '94 Cascaded combination of cancelling co-channel interference and decoding of error-correcting codes for CDMA A. Saifuddin;R. Kohmo;H. Imai
  6. IEEE Trans. Comm. v.38 Multistage detection in asynchronous code division multiple access communications M. K. Varanasi;B. Aazhang
  7. IEEE JSAC v.11 A spread spectrum multiaccess system with cochannel interference cancellation for multipath fading channels C. Y. Yoon;R. Kohno;H. Imai
  8. IEICE Trans. on Communication v.E76-B Cascaded co-channel Interference canceling and diversity combining for spread-spectrum multi-access over multipath fading channels R. Kohno;C. Y. Yoon;H. Imai
  9. IEEE 5th Inter. Conf. v.1 Interference cancellation for SSMA communications with diversity combining and system imperfections L. C. Hui;K. B. Letaief
  10. IEEE Trans. Comm. v.47 Interference suppression for DS/CDMA R. Singh;L. B. Milstein
  11. IEEE Trans. Comm. v.47 Asynchronous multiple-access interference suppression and chip waveform selection with aperiodic random sequences T. F. Wong;T. M. Lok;J. S. Lehnert
  12. Multiuser Detection Sergio Verdu
  13. Theory and application of spread spectrum systems A. W. Lam;S. Tantaratan
  14. Introduction to spread-spectrum communications R. L. Perterson;R. E. Ziemer;D. E. Borth