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Effects of interference on carrier tracking in fading and symbol synchronization.

机译：衰落和符号同步中干扰对载波跟踪的影响。

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摘要

Synchronization is a very important part of every digital communication receiver. While in bandpass coherent transmission, frequency and phase synchronization play a very important role in reliable transmission, symbol timing recovery is a necessary part of every baseband and bandpass coherent receiver. This dissertation deals with the problem of synchronization in the presence of fading and interference.In the second part, the problem of symbol timing recovery is investigated in systems that are subject to intersymbol interference and non-data-aided maximum likelihood synchronizer is derived in these channels. Then, a new simple bound on the performance of synchronizers is derived and compared to the previously known lower bounds. It is shown that while this lower bound solves the shortcomings of the well known modified Cramer-Rao bound at small values of signal-to-noise-ratio, it is much easier to compute compared to another well known bound, the detection theory bound.First, the performance of an automatic frequency control loop is investigated using two parameters of average switching rate and mean time to loss of lock. These parameters are derived in closed-form or as integral-form formulas for different scenarios of modulated and unmodulated signals in different fading channels when there is one interference signal present at the input of the AFC. Then, the results are generalized to the noisy fading scenario and it is shown that in Rayleigh fading case, the performance of AFC becomes better when the desired signal is noisier.
机译：同步是每个数字通信接收器中非常重要的部分。虽然在带通相干传输中，频率和相位同步在可靠传输中起着非常重要的作用，但符号定时恢复是每个基带和带通相干接收机的必要组成部分。第二部分研究了码间干扰下系统中符号定时恢复的问题，并推导了无数据辅助的最大似然同步器。渠道。然后，导出同步器性能的新简单界限并将其与先前已知的下限进行比较。结果表明，尽管该下限解决了在信噪比较小的情况下众所周知的改进的Cramer-Rao界限的缺点，但与另一个众所周知的界限（检测理论界限）相比，它的计算要容易得多。首先，使用平均切换速率和平均失锁时间这两个参数来研究自动频率控制环路的性能。当AFC的输入端存在一个干扰信号时，这些参数以闭式或积分式公式导出，用于不同衰落信道中调制和未调制信号的不同情况。然后，将结果推广到有噪声的衰落场景，结果表明在瑞利衰落的情况下，当所需信号噪声较大时，AFC的性能会更好。

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  • 作者

    Emad, Amin.;

  • 作者单位

    University of Alberta (Canada).;

  • 授予单位 University of Alberta (Canada).;
  • 学科 Engineering Electronics and Electrical.
  • 学位 M.Sc.
  • 年度 2009
  • 页码 89 p.
  • 总页数 89
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 老年病学;
  • 关键词

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