Proceedings of the Korea Institute of Convergence Signal Processing (융합신호처리학회 학술대회논문집)

The Korea Institute of Convergence Signal Processing (한국융합신호처리학회)
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The Effect of Time Belay on Adaptive QAM Modems

적응 QAM 모뎀의 시간지연에 대한 영향

  • Y. H. Chung (Dept. of Information and Communications, Dongeui University) ;
  • Park, J. O. (Dept. of Information and Communications, Dongeui University)
  • Published : 2000.08.01
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Abstract

Multilevel modulation schemes are known to be highly bandwidth efficient. By varying modulation level adaptively according to channel conditions (i.e. adaptive QAM schemes or AQAM), high bandwidth efficiency can be achieved. This paper considers the effect of time delay on the adaptive QAM schemes in dispersive fading channels. In order to undertake investigations effectively, a simulator has been developed. The simulation results show that the BER performance obtained for the wideband channel with a delay spread of 0.75 $\mu$sec is better than 10$^{-4}$ with a SNR value of 40 ㏈ and ABPS is found to be approximately 5.5.

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