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Reliable content delivery to handheld devices in satellite broadcast/multicast systems

机译：可靠地将内容传送到卫星广播/多播系统中的手持设备

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摘要

Multicast is a key technology enabling efficient point to multi-point communications, be they wireless- or wireline-based. Satellite systems, such as Satellite Digital Multimedia Broadcasting (S-DMB), are ideal for multicast due to their inherent wide geographic reach. However, the capacity constraints in satellite systems and the possibility of feedback implosion do not favour the provision of a return channel for user feedback which is a must for providing full reliability in content delivery. Two packet loss mitigation mechanisms that become relevant in this scenario are data carousels and packet-level forward error correction (FEC). The research herein aims to enhance reliable content delivery mechanisms with emphasis on those applicable to S-DMB. The work carried out is divided into three main parts. The first part compares various FEC codes under potential S-DMB burst losses. The simulation results show that one FEC code is the best at protecting all relevant file sizes in sharp contrast to the conventional thinking that small FEC codes are better than large codes at protecting small files, and vice versa for large files. In the second part, two aspects of a FEC code known as two-dimensional Reed Solomon (2D RS) are explored. A number of 2D RS file success rate bounds are derived and compared to simulation results. The comparison demonstrates that two of the derived bounds, an upper and lower, can be used in conjunction to reasonably estimate the real performance of 2D RS without the need for time consuming simulations. A number of 2D RS decoding algorithms are also proposed. The experimental results reveal useful insights for the pursuit of more efficient decoding algorithms, hi the third part, the integration of data carousels and FEC is investigated via analytical and simulation means while considering different content properties, FEC codes, data retrieval techniques, and ways of assigning FEC redundancy to various files on a carousel. The results show that the average content download time can be optimised, and that FEC redundancy is the main factor therein. The investigations herein are different from other works which largely investigate the two schemes separately or are rather limited when they examine the joint scheme.
机译：组播是一项关键技术，可实现基于无线或有线的高效点对多点通信。诸如卫星数字多媒体广播（S-DMB）之类的卫星系统因其固有的广泛地理覆盖范围而非常适合多播。然而，卫星系统中的容量限制和反馈内爆的可能性并不有利于提供用于用户反馈的返回信道，这是在内容传递中提供完全可靠性所必须的。在这种情况下，与之相关的两种减少数据包丢失的机制是数据轮播和数据包级前向纠错（FEC）。本文的研究旨在增强可靠性的内容传递机制，重点是适用于S-DMB的机制。进行的工作分为三个主要部分。第一部分比较了潜在S-DMB突发损失下的各种FEC码。仿真结果表明，与传统的认为小FEC代码比大代码在保护小文件方面要好，反之亦然，大文件相比，一种FEC代码最适合保护所有相关文件大小。在第二部分中，探讨了称为二维Reed Solomon（2D RS）的FEC代码的两个方面。导出了许多2D RS文件成功率范围并将其与仿真结果进行比较。比较表明，可以结合使用两个导出的边界（上限和下限）来合理估计2D RS的实际性能，而无需进行费时的仿真。还提出了许多2D RS解码算法。实验结果揭示了寻求更高效解码算法的有用见解。在第三部分中，通过分析和模拟手段研究了数据轮播和FEC的集成，同时考虑了不同的内容属性，FEC代码，数据检索技术和方法。为轮播上的各种文件分配FEC冗余。结果表明，平均内容下载时间可以得到优化，而FEC冗余是其中的主要因素。本文的研究与其他工作大不相同，其他工作在很大程度上对这两种方案进行了单独研究，或者在他们研究联合方案时受到很大限制。

著录项

  • 作者

    Chipeta, Malumbo.;

  • 作者单位

    University of Surrey (United Kingdom).;

  • 授予单位 University of Surrey (United Kingdom).;
  • 学科 Electrical engineering.
  • 学位 Ph.D.
  • 年度 2007
  • 页码 185 p.
  • 总页数 185
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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