• Title/Summary/Keyword: multiuser channel

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Algorithm and experimental verification of underwater acoustic communication based on passive time reversal mirror in multiuser environment (다중송신채널 환경에서 수동형 시역전에 기반한 수중음향통신 알고리즘 및 실험적 검증)

  • Eom, Min-Jeong;Oh, Sehyun;Kim, J.S.;Kim, Sea-Moon
    • The Journal of the Acoustical Society of Korea
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    • v.35 no.3
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    • pp.167-174
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    • 2016
  • Underwater communication is difficult to increase the communication capacity because the carrier frequency is lower than that of radio communications on land. This is limited to the bandwidth of the signal under the influence of the characteristics of an ocean medium. As the high transmission speed and large transmission capacity have become necessary in the limited frequency range, the studies on MIMO (Multiple Input Multiple Output) communication have been actively carried out. The performance of the MIMO communication is lower than that of the SIMO (Single Input Multiple Output) communication because cross-talk occurs due to multiusers along with inter symbol interference resulting from the channel characteristics such as delay spread and doppler spread. Although the adaptive equalizer considering multi-channels is used to mitigate the influence of the cross-talk, the algorithm is normally complicated. In this paper, time reversal mirror technique with the characteristic of a self-equalization will be applied to simplify the compensation algorithm and relieve the cross-talk in order to improve the communication performance when the signal transmitted from two channels is received over interference on one channel in the same time. In addition, the performance of the MIMO communication based on the time reversal mirror is verified using data from the SAVEX15(Shallow-water Acoustic Variability Experiment 2015) conducted at the northern area of East China Sea in May 2015.