rdf-syntax-grammar
mods:
  schema location: http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
  title info:
    title: Exit charts based analysis and design of rateless codes for the erasure and Gaussian channels
  name:
    name part: Mothi Venkatesan, Sabaresan.
    role:
      role term: creator
  name:
    name part: Narayanan, Krishna R.
    role:
      role term: thesis advisor.
  type of resource: text
  genre: bibliography
  origin info:
    place:
      place term: txu
    date issued: 2010
    issuance: monographic
  language:
    language term: eng
  physical description:
    form: electronic
    form: remote
    extent: 1 online resource.
  abstract: Luby Transform Codes were the first class of universal erasure codes introduced to fully realize the concept of scalable and fault-tolerant distribution of data over computer networks, also called Digital Fountain. Later Raptor codes, a generalization of the LT codes were introduced to trade off complexity with performance. In this work, we show that an even broader class of codes exists that are near optimal for the erasure channel and that the Raptor codes form a special case. More precisely, Raptorlike codes can be designed based on an iterative (joint) decoding schedule wherein information is transferred between the LT decoder and an outer decoder in an iterative manner. The design of these codes can be formulated as a LP problem using EXIT Charts and density evolution. In our work, we show the existence of codes, other than the Raptor codes, that perform as good as the existing ones. We extend this framework of joint decoding of the component codes to the additive white Gaussian noise channels and introduce the design of Rateless codes for these channels. Under this setting, for asymptotic lengths, it is possible to design codes that work for a class of channels defined by the signal-to-noise ratio. In our work, we show that good profiles can be designed using density evolution and Gaussian approximation. EXIT charts prove to be an intuitive tool and aid in formulating the code design problem as a LP problem. EXIT charts are not exact because of the inherent approximations. Therefore, we use density evolution to analyze the performance of these codes. In the Gaussian case, we show that for asymptotic lengths, a range of designs of Rateless codes exists to choose from based on the required complexity and the overhead. Moreover, under this framework, we can design incrementally redundant schemes for already existing outer codes to make the communication system more robust to channel noise variations.
  note: by Sabaresan Mothi Venkatesan.
  note: "Major Subject: Electrical Engineering"
  note: Title from author supplied metadata (automated record created 2010-03-12 12:08:51).
  note: Electronic resource.
  note: Master of Science Texas A&M University 2007 http://hdl.handle.net/1969.1/ETD-TAMU-1924
  note: Includes bibliographical references.
  note: Text (Thesis)
  subject:
    topic: Major electrical engineering
  subject:
    topic: Raptor Codes
  subject:
    topic: LT Codes
  subject:
    topic: EXIT Charts
  subject:
    topic: Universal Codes
  subject:
    topic: Graphical Codes
  subject:
    topic: Rateless Codes
  subject:
    topic: LDPC Codes
  subject:
    topic: Message Passing
  subject:
    topic: Belief Propogation
  subject:
    topic: Density Evolution
  identifier: http://hdl.handle.net/1969.1/ETD-TAMU-1924
  record info:
    record content source: TXA
    record creation date: 100429
    record change date: 20151201150204.0
    record identifier: in00002569271