안테나 배열을 사용한 DS-SS 시스템을 위한 병렬 포착 방식과 페이딩 채널에서의 성능

Parallel Acquisition Scheme for DS-SS Systems Using Antenna Arrays and Its Performance in a Fading Channel

  • 발행 : 2000.01.01

초록

안테나 배열을 사용하는 직접 대역 확산 시스템에서 초기 동기 포착을 위하여 안테나 배열을 사용하는 병렬 포착 방식을 제안한다. 제안된 병렬 방식은 단일 안테나를 사용하는 기존의 병렬 방식에 비하여 포착이 가능한 SNR의 범위를 크게 낮출 수 있다. 이를 위하여, 동일한 PN (pseudo-noise) 위상에 해당하는 안테나 배열로부터의 독립된 판정 변수들을 합하여 새로운 판정 변수로 사용한다. 성능분석을 위하여 부가성 백색 가우시안 잡음과 Rayleigh 페이딩 채널하에서 검출확률, 손실확룔, 오인확룔이 유도되며, 이러한 값들을 이용하여 제안된 방식의 평균 포착 성능을 평가한다. 수치적인 분석 결과를 통하여, 제안된 시스템의 성능은 안테나의 개수가 증가함에 따라 지속적으로 향상된다는 사실을 확인할 수 있다.

We propose a parallel acquisition scheme using antenna arrays for initial acquisition of direct-sequence spread-spectrum (DS-SS) signals. The proposed parallel scheme can lower substantially the range of detectable signal-to-noise ratio (SNR) as compared to the conventional parallel scheme with a single antenna. The proposed scheme uses the sum of the independent decision samples from antenna arrays corresponding to an identical subsequence of the pseudonoise (PN) code as a decision variable. We derive the probabilities of detection, missing, and false alarm under an additive white Gaussian noise (AWGN) channel and a flat Rayleigh fading channel. Using these, we get the mean acquisition time of the proposed scheme. From numerical results, we see that the acquisition performance becomes improved continually as the number of antennas increases.

키워드

참고문헌

  1. G. R. Cooper and R. W. Nettleton, 'A spread spectrum technique for high capacity mobile communications,' IEEE Trans. Veh. Tech., vol. 27, no. 4, pp. 264-275, Nov. 1978 https://doi.org/10.1109/T-VT.1978.23758
  2. R. L. Pickholtz, D. L. Schilling, and L. B. Milstein, 'Theory of spread-spectrum communications A tutorial,' IEEE Trans. Comm., vol. 30, no. 5, pp. 855-884, May 1982 https://doi.org/10.1109/TCOM.1982.1095533
  3. R. L. Pickholtz, L. B. Milstein, and D. L. Schilling, 'Spread spectrum for mobile communications,' IEEE Trans. Veh. Tech., vol. 40, no. 2, pp. 313-321, May 1991 https://doi.org/10.1109/25.289412
  4. K. S. Gilhousen, I. M. Jacobs, R. Padovani, A. J. Viterbi, L. A. Weaver, and C. E. Wheatley III, 'On the capacity of a cellular CDMA system,' IEEE Trans. Veh. Tech., vol. 40, no. 2, pp. 303-312, May 1991 https://doi.org/10.1109/25.289411
  5. A. Polydoros and C. Weber, 'A unified approach to serial spread spectrum code acquisition Part I : General theory,' IEEE Trans. Comm., vol. 32, no. 5, pp. 542-549, May 1984
  6. A. Polydoros and C. Weber, 'A unified approach to serial spread spectrum code acquisition Part II : A matched filter receiver,' IEEE Trans. Comm., vol. 32, no. 5, pp. 550-560, May 1984
  7. E. A. Sourour and S. C. Gupta, 'Direct-sequence spread spectrum parallel acquisition in a fading mobile channel,' IEEE Trans. Comm., vol. 38, no. 7, pp. 992-998, July 1990 https://doi.org/10.1109/26.57497
  8. R. R. Rick and L. B. Milstein, 'Parallel acquisition in mobile DS-CDMA system,' IEEE Trans. Comm., vol. 45, no. 11, pp. 1466-1476, Nov. 1997 https://doi.org/10.1109/26.649775
  9. V. M. Jovanovic, 'Analysis of strategies for serial-search spread-spectrum code acquisition Direct approach,' IEEE Trans. Comm., vol. 36, no. 11, pp. 1208-1220, Nov. 1988 https://doi.org/10.1109/26.8927
  10. W. R. Braun, 'PN acquisition and tracking performance in DS/CDMA systems with symbol length spreading sequences,' IEEE Trans. Comm., vol. 45, no. 12, pp. 1595-1601, Dec. 1997 https://doi.org/10.1109/26.650238
  11. J. H. Winters, 'Optimum combining in digital mobile radio with cochannel interference,' IEEE J. Select. Areas Comm., vol. 2, no. 4, pp. 528-539, July 1984 https://doi.org/10.1109/JSAC.1984.1146095
  12. S. Anderson, M. Millnert, M. Viberg, and B. Wahlberg, 'An adaptive array for mobile communication systems,' IEEE Trans. Veh. Tech., vo. 40, no. 1, pp. 230-236, Feb. 1991 https://doi.org/10.1109/25.69993
  13. S. C. Swales, M. A. Beach, D. J. Edwards, and J. P. McGeehan, 'The performance enhancement of multibeam adaptive base station antennas for cellular land mobile radio systems,' IEEE Trans. Veh. Tech., vol. 39, no. 1, pp. 56-67, Feb. 1990 https://doi.org/10.1109/25.54956
  14. H. Liu and G. Xu, 'Smart antennas in wireless systems: Uplink multiuser blind channel and sequence detection,' IEEE Trans. Comm., vol. 45, no. 2, pp. 187-199, Feb. 1997 https://doi.org/10.1109/26.554367
  15. J. C. Wang and A. S. Mohan, 'An adaptive antenna array with parallel beamformers for indoor radio channel enhancement,' in Proc. VTC'97, vol. 1, pp. 188-192, May 1997 https://doi.org/10.1109/VETEC.1997.596345
  16. Z. Zvonar, 'Combined multiuser detection and diversity receiption for wireless CDMA systems,' IEEE Trans. Veh. Tech., vol. 45, no. 1, pp. 205-211, Feb. 1996 https://doi.org/10.1109/25.481839
  17. A. F. Naguib, A. Paulraj, and T. Kailath, 'Capacity improvement with base station antenna arrays in cellular CDMA,' IEEE Trans. Veh. Tech., vol. 43, no. 3, pp. 691-698, Aug. 1994 https://doi.org/10.1109/25.312780
  18. A. F. Naguib and A. Paulraj, 'Performance of wireless CDMA with M-ary orthogonal modulation and cell site antenna arrays,' IEEE J. Select. Areas Comm., vol. 14, no. 9, pp. 1770-1783, Dec. 1996 https://doi.org/10.1109/49.545700
  19. J. C. Liberti and T. S. Rappaport, 'Analytical results for capacity improvements in CDMA,' IEEE Trans. Veh. Tech. vol. 43, no. 3, pp. 680-690, Aug. 1994 https://doi.org/10.1109/25.312781
  20. Y. Wang and J. R. Cruz, 'Performance analysis of CDMA cellular systems with adaptive antenna arrays over multipath channels,' in Proc. ICC' 96, vol. 1, pp. 536-540, June 1996
  21. E. A. Sourour and S. C. Gupta, 'Direct-sequence spread spectrum parallel acquisition in nonselective and frequency-selective Rician fading channels,' IEEE J. Select. Areas Comm., vol. 10, no. 3, pp. 535-544, Apr. 1992 https://doi.org/10.1109/49.127775
  22. B. B. Ibrahim and A. H. Aghvami, 'Direct sequence spread spectrum matched filter in frequency-selective Rayleigh fading channels,' IEEE J. Select. Areas Comm., vol. 12, no. 5, pp. 885-890, June 1995 https://doi.org/10.1109/49.298062
  23. M. G. El-Tarhuni and A. U. Sheikh, 'Adaptive filtering based DS/SS code acquisition in frequency selective and flat Rayleigh fading channels,' in Proc. VTC'97, vol. 3, pp. 1624-1628, May 1997 https://doi.org/10.1109/VETEC.1997.605833
  24. J. G. Proakis, Digital Communications, 3rd Ed., New York, McGraw-Hill, 1995
  25. H. Stark and J. W. Woods, Probability, Random Processes and Estimation Theory for Engineers, 2nd Ed., New Jersey, Prentice-Hall, 1994
  26. I. S. Gradshteyn and I. M. Ryzhik, Table of Integrals, Series and Products, corrected and enlarged edition, New York, Academic Press, 1980