Performance Evaluation of QAM System in Faded Digital Wireless Communication Environments

디지탈무선통신 방식에서 페이딩의 영향을 고려한 QAM 방식의 성능평가

  • 임성준 (한국전자통신연구원 전파응용연구실) ;
  • 유흥균 (충북대학교 전자공학과)
  • Published : 1997.12.01

Abstract

In this paper we evaluate the performances of two types of 16-QAM system such as square QAM and star QAM. First we analyze the performances of QAM systems under AWGN(adaptive white Gaussian noise) and afterward analyze the performances under fading environments. The performances of QAM systems in case of using the PSAM(Pilot Symbol Assisted Modulation) are finally evaluated under fading environments. In conclusion, the Square QAM's performance is better than star QAM in AWGN. But the performances of the both QAM systems are very poor under the fading environments. QAM performance using the PSAM system is verified to be improved in that case, and the star QAM's performance is better than square QAM.

이 논문에서는 신호점 구성에 따른 square QAM과 star QAM의 2가지 종류의 QAM 시스템을 평가하였으며, 처음에는 잡음환경, 두 번째는 페이딩 환경, 그리고 마지막으로 PSAM 방식을 이용하였을 경우의 QAM 시스템의 성능평가를 하였다. 결론적으로, 잡음환경에서는 square QAM 시스템의 성능이 더 좋지만, 페이딩이 존재하면 star QAM의 성능이 더 뛰어나다. 또한 페이딩 채널에서는 전반적인 성능 악화로 인하여 두 시스템의 성능이 열화된다. 그러나 PSAM 방식에서, 상당한 개선효과를 얻게 되었으며, 이 경우 square QAM에 비하여 star QAM의 성능개선효과가 더 뚜렷하다.

Keywords

References

  1. IEEE Trans. on Veh. Techn. v.39 no.4 A Subband Coding BCH Coding and 16-QAM System for Mobile Radio Speech Communications L. Hanzo;R. Steel;P.M. Fortune
  2. IEICE Trans. Comms. v.E75-B no.6 On the computation of 16-QAM and 64-QAM performance on Rayleigh fading channels P. M. Fortune;L.Hanzo;R. Steele
  3. IEEE Proceedings v.139 no.4 Transmission of Digitally Encoded Speech at 1.2 KBd for PCN L. Hanzo;R. Salami;R. Steele; P.M. Fortune
  4. Channel coding K.H.H. Wong;L. Hanzo
  5. IEEE Int. Conf. Comms. The use of transparent tone in hand for coherent sata schemes A. Bateman;J.P. McGeehan
  6. IEE Int. Conf. Comms v.68 Feedforward transparent tone in band for rapid fading protection in mutipath fading A. Bateman;J.P. McGeehan
  7. IEEE Tr. on Veh. Techn. v.40 no.4 An Analysis of Pilot Symbol Assisted Modulation for Rayleigh Fading Channels J.K. Cavers
  8. Digital communications B. Sklar
  9. IEEE Press Modern QAM W.T. Webb;L. Janzo
  10. Electronic Letters v.28 no.17 Analysis of 16-APSK modilation in AWGN and Rayleigh fading channels Y. C. Chow;A.R. Nix;J.P. AcGeehan
  11. 아날로그와 디지탈 통신 진년강
  12. IEEE Tr. on Video Systems 16-QAM Transmission of Subband Coded Images via Microcelluar Mobile Channels R. Stedman;H. Gharavi;L. Hanzo;R. Steele
  13. Mobiel Radio Communications R. Steel