Performance Analysis of DS/CDMA with PLL Gain under the Nakagami-m Fading Channel

나카가미-m 페이딩 채널 하에서 PLL 이득에 따른 DS/CDMA의 성능 분석

  • Published : 2000.09.01

Abstract

A received signal in mobile communication environments exhibits variation in both amplitude and phase due to the multipath fading. Therefore we analyzed the performance of DS/CDMA(Direct Sequence/code Division Multiple Access) DPSK(Differential Phase Shift Keying) system for the variations of PLL(Phase Locked Loop) gain with Tikhonov probability density function, assuming that the phase difference between transmitter and receiver signals is phase error. As a result, it is discovered that the performance of system could be improved by the control of PLL gain in compared with the DPSK system which does not consider the phase error. If the PLL gain is 1dB, the difference of two systems is 4.8dB and 0.4dB at 7dB. and if 30dB, it coincides. From above, it

이동통신환경에서 수신신호의 진폭과 위상성분은 다중경로에 의한 페이딩(Fading) 영향을 받는다. 본 논문에서는 송수신 신호의 위상 차를 위상에러로 가정하고 Tikhonov 확률밀도함수를 이용하여 PLL(Phase Locked Loop)이득의 변화에 대한 DS/CDMA(Direct Sequence/code Division Multiple Access) DPSK(Differential Phase Shift Keying)시스템의 성능을 분석하였다. 그 결과, 위상에러를 고려하지 않은 DPSK시스템과 비교하여 수신기의 PLL이득을 조정함으로써 시스템의 성능을 향상시킬 수 있음을 알 수 있었다. 시스템의 비트 포율이 10-2에서 PLL이득이 1㏈에서 4.8㏈, 7㏈에서는 0.4㏈의 성능차를 보이며 30㏈에서는 두 시스템의 성능이 일치하게되어 PLL이 요구하는 이득의 상한이 30㏈임을 입증하였다.

Keywords

References

  1. IEEE Trans, Vehic. Techno. v.40 On the capacity of a cellular CDMA system K. S. Gilhousen, et al.
  2. IEEE Trans. Vehic. Techno. v.40 Overview of cellular CDMA W. C. Y. Lee
  3. IEEE Trans. Vehic. Technol v.43 The Evolution of digital wireless thchnology from space exploration to personal communication sevices A. J. Viterbi
  4. IEEE Trans. Aerosp. Electron. Syst. v.AES-2 Phase-shift-keyed signal detection with noisy reference signals W. C. Lindsey
  5. IEEE Trans. Aerosp. Electron. Syst. v.AES-12 PSK performance with imperfect carrier phase recovery V. K. Prabhu
  6. IEEE Trans. COMM. v.45 no.1 Partially Coherent DS-SS Performance in Frequency Selective Multipath Fading Thomas Eng;Laurence B. Milstein
  7. Proceeding of the Golbecom '96 v.2 Performance Analysis of Noncoherent Binary DS/CDMA System in a Nakagami Multpath Channel with Abitrary Parameter George Efthymoglou
  8. Digital Communications J. G. Proakis
  9. Introduction to Spread Spectrum Communication Peterson;Ziemer;Borth
  10. IEEE Trans, Commun. v.42 DS-CDMA with predetection diversity for indoor radio communications J. Wang, et al.