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首页> 外文学位 >The communications performance of single-carrier and multi-carrier quadrature amplitude modulation in RF carrier phase noise.
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The communications performance of single-carrier and multi-carrier quadrature amplitude modulation in RF carrier phase noise.

机译：RF载波相位噪声中单载波和多载波正交幅度调制的通信性能。

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摘要

Multi-carrier modulations have generated strong interest recently because of the challenging characteristics of important contemporary channels. While the idea of partitioning spectrally using orthogonal frequency division multiplexing (OFDM) was developed over thirty years ago, its implementation as a practical solution to a communications system problem is much more recent due to advances in digital signal processing and VLSI. Implementation has brought about a simultaneous increase in developing analysis that allow the performance characteristics of the approach to be understood in practical channels. Example channels where OFDM is being strongly considered are data communications over CATV channels and wireless applications such as digital terrestrial broadcasting. Widespread consideration of OFDM as a primary transport mechanism has occurred to date only for high speed data over the twisted pair channel. In this application, the technology is referred to as the Asymmetric Digital Subscriber Line (ADSL). Unlike that application, however, CATV and wireless systems represent RF channels. As such, one important characteristic of each is the phase jittery nature of low-cost, high frequency synthesized carriers. The research will present unique results indicating how these impairments degrade the OFDM system. The approach taken is to model the untracked jitter variation as a lowpass process, note the breakdown of traditional assumptions associated with single carrier modulations, and proceed with analytical solutions from this practical model. The single carrier solutions required are developed, including solutions for slow and rapid phase noise for standard and offset 16-QAM. Results for 64-QAM are also developed, and can be easily extended to any rectangular constellation, such as 256-QAM or 1024-QAM. A comparison of the various simplifying analysis assumptions is made to contrast with exact performance curves when phase noisy RF channels are encountered. A straightforward technique to improve link margin on phase-noise limited, slow jitter channels is presented. Finally, system design guidelines are developed for the difficult moderately varying jitter situation, critical for multi-carrier systems that rely on multiple subchannels of individually low symbol rate.
机译：由于重要的现代频道具有挑战性的特性，最近多载波调制引起了人们的极大兴趣。尽管使用正交频分复用（OFDM）在频谱上进行划分的想法是三十多年前提出的，但是由于数字信号处理和VLSI的进步，其作为通信系统问题的实际解决方案的实现要近得多。实施带来了开发分析方面的同步增长，这使得可以在实际渠道中理解该方法的性能特征。强烈考虑使用OFDM的示例信道是通过CATV信道进行的数据通信以及诸如数字地面广播之类的无线应用。迄今为止，仅对于双绞线信道上的高速数据，已经将OFDM作为主要传输机制进行了广泛的考虑。在此应用程序中，该技术称为非对称数字用户线路（ADSL）。但是，与该应用程序不同，CATV和无线系统代表RF频道。因此，每种天线的一个重要特征是低成本，高频合成载波的相位抖动特性。这项研究将提出独特的结果，表明这些损害如何降低OFDM系统的性能。采取的方法是将未跟踪的抖动变化建模为低通过程，注意与单载波调制相关的传统假设的分解，并从该实际模型中进行分析。开发了所需的单载波解决方案，包括用于标准和偏移16-QAM的慢速和快速相位噪声的解决方案。还开发了64-QAM的结果，可以轻松扩展到任何矩形星座，例如256-QAM或1024-QAM。当遇到相位噪声射频通道时，将各种简化分析假设进行比较，以与精确的性能曲线形成对比。提出了一种提高相位噪声受限，缓慢抖动通道上的链路裕量的直接技术。最后，针对困难的适度变化的抖动情况开发了系统设计指南，这对于依赖多个单独的低符号率子信道的多载波系统至关重要。

著录项

  • 作者

    Howald, Robert Landis.;

  • 作者单位

    Drexel University.;

  • 授予单位 Drexel University.;
  • 学科 Engineering Electronics and Electrical.
  • 学位 Ph.D.
  • 年度 1997
  • 页码 277 p.
  • 总页数 277
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 无线电电子学、电信技术;
  • 关键词

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