Coupled LDPC Codes: Complexity Aspects of Threshold Saturation

Summary, in English

We analyze the convergence behavior of iteratively decoded coupled LDPC codes from a complexity point of view. It can be observed that the thresholds of coupled regular LDPC codes approach capacity as the node degrees and the number L of coupled blocks tend to infinity. The absence of degree two variable nodes in these capacity achieving ensembles implies for any fixed L a doubly exponential decrease of the error probability with the number of decoding iterations I, which guarantees a vanishing block error probability as the overall length n of the coupled codes tends to infinity at a complexity of O(n log n). On the other hand, an initial number of iterations Ibr is required until this doubly exponential decrease can be guaranteed, which for the standard flooding schedule increases linearly with L. This dependence of the decoding complexity on L can be avoided by means of efficient message passing schedules that account for the special structure of the coupled ensembles.

• Författare: Michael Lentmaier; Gerhard Fettweis
• Avdelning/ar: ELLIIT: the Linköping-Lund initiative on IT and mobile communication
• Publiceringsår: 2011
• Språk: Engelska
• Sidor: 668-672
• Publikation/Tidskrift/Serie: 2011 IEEE Information Theory Workshop
• Fulltext: - 156 kB; Download statistics
• Länkar: http://dx.doi.org/10.1109/ITW.2011.6089581
• Dokumenttyp: Konferensbidrag
• Förlag: IEEE - Institute of Electrical and Electronics Engineers Inc.
• Ämne: Electrical Engineering, Electronic Engineering, Information Engineering
• Nyckelord: spatial coupling; LDPC codes; LDPC convolutional codes
• Conference name: IEEE Information Theory Workshop (ITW), 2011
• Conference date: 2011-10-16 - 2011-10-20
• Conference place: Paraty, Brazil
• Status: Published
• Forskningsgrupp: Telecommunication Theory
• ISBN/ISSN/Övrigt: ISBN: 978-1-4577-0438-3