Journal of Advanced Navigation Technology (한국항행학회논문지)

The Korean Navigation Institute (한국항행학회)
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EVM Based SNR Estimation Performance in Cross QAM Using Selected Constellation Points

Cross QAM의 선택적 성좌점을 사용하는 EVM 기반 SNR 추정 성능

  • Kwak, Jae-Min (Division of Marine Electronics and Communication Eng., Mokpo National Maritime University)
  • 곽재민 (목포해양대학교 해양전자통신공학부)
  • Received : 2012.04.10
  • Accepted : 2012.06.30
  • Published : 2012.06.30
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Abstract

In this paper, we investigate the signal to noise ratio (SNR) estimation performance of Cross quadrature amplitude modulation (QAM), which is being used for asymmetric digital subscriber line (ADSL), very high bit rate digital subscriber line (VDSL), and digital video broadcasting - cable (DVB-C), and has been found to be useful in adaptive modulation and blind equalization. At first, the symbol error rate (SER) performance of Cross QAM is analyzed in Rayleigh fading channel. Then we suggest error vector magnitude (EVM) based SNR estimation utilizing the selected constellation points having different types of decision region from one another, and verify that SNR estimation performance of each points have different performance pattern through simulation. From the simulation results, it has been found that when suggested selected constellation points are used for SNR estimation in Cross QAM, estimation performance is enhanced in additive white Gaussian noise (AWGN) channel or Ricean fading channel.

본 논문에서는 ADSL, VDSL, DVB-C 등의 통신 시스템에 적용되고 있고, 적응변조나 blind equalization에서 유용하게 사용될 수 있는 Cross QAM의 SNR 추정 성능에 대해 분석하였다. 우선 레일리 페이딩 채널에서의 Cross QAM의 심볼에러율을 분석하였다. 그리고, Cross QAM의 성좌점에 대한 판정영역 특성에 착안하여, 성좌 점별로 EVM 기반의 SNR 추정기법을 사용하는 것을 제안하고, 성좌점별로 SNR 추정성능이 다르게 나타남을 시뮬레이션을 통해 확인하였다. 시뮬레이션 결과로부터 Cross QAM에서 SNR 추정에 사용하는 성좌점을 선택적으로 사용하면, AWGN 채널이나 라이시안 페이딩 채널에서 추정성능을 개선할 수 있음을 확인하였다.

Keywords

References

  1. J. G. Smith, "Odd-bit quadrature amplitude-shift keying," IEEE Trans. Commun., vol. 23. no. 3, pp. 385-389, Mar. 1975. https://doi.org/10.1109/TCOM.1975.1092806
  2. S. Panigrahi and T. Le-Ngoct, "Fine-granularity loading schemes using adaptive Reed-Solomon coding for discrete multitone modulation systems," in Proc. IEEE ICC'05, vol. 2, Seoul, Korea, pp 1352-1356, May 2005.
  3. V. Demjanenko, P. Marzec, and A. Torres, "Reasons to use non squared QAM constellations with independent I&Q in PAN systems," IEEE P802.15-15-03-0311-00-003a, July 2003.
  4. J. Li, X.-D. Zhang, and N. C. Beaulieu, "Precise calculation of the SEP of 128- and 512-Cross-QAM in AWGN," IEEE Commun. Lett., vol. 12, no. 1, pp. 1-3, Jan. 2008. https://doi.org/10.1109/LCOMM.2008.071450
  5. Hua Yu and Gang Wei, "Symbol error probability of cross QAM in Rayleigh fading channels," IEEE Commun. Lett., vol. 14, no. 5, May 2010.
  6. IEEE Std 802.16a/D7.0-2002, Part16 : "Air Interface for Fixed Broadband Wireless Access Systems Medium Access Control Modification and Additional Physical Layer Specifications for 2-11 GHz," 2002.
  7. 김명익, 안상식, "새로운 SNR 추정방법을 이용한 적응 OFDM 시스템," 대한전자공학회 논문지 43권 TC편 3호, 2006.