Coding vs. packet retransmission over noisy channels

Dror Baron, Shriram Sarvotham, Richard G. Baraniuk

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Scopus citations


In many packet-based communication systems such as TCP/IP-based systems, packets are communicated over a noisy physical layer (a channel), and if a packet cannot be decoded correctly, then the transport layer retransmits it. Of course, retransmissions consume significant resources and their use should be limited. However, decreasing the likelihood of retransmission requires to encode the packets with strong channel codes in the physical layer, which also requires additional channel resources. In this paper, we study the cross-layer tradeoff between coding and packet retransmissions, and optimize over the total channel resource consumption. We show that as the packet length k increases, the redundancy r beyond the k/C channel uses implied by Shannon's channel capacity C is ⊖(√k In(k)) extra channel uses. Moreover, as k increases we must use stronger channel codes. We then apply these results to universal coding over a piecewise memoryless channel with transitions between unknown i.i.d. statistics. Our constructive universal algorithm has redundancy r = O(k 2/3 √In(k)) using packets of polynomially increasing lengths while accounting for possible packet drops caused by transitions in the statistics.

Original languageEnglish (US)
Title of host publication2006 IEEE Conference on Information Sciences and Systems, CISS 2006 - Proceedings
PublisherInstitute of Electrical and Electronics Engineers Inc.
Number of pages5
ISBN (Print)1424403502, 9781424403509
StatePublished - Jan 1 2006
Event2006 40th Annual Conference on Information Sciences and Systems, CISS 2006 - Princeton, NJ, United States
Duration: Mar 22 2006Mar 24 2006


Other2006 40th Annual Conference on Information Sciences and Systems, CISS 2006
Country/TerritoryUnited States
CityPrinceton, NJ


  • Channel coding
  • Cross-layer design
  • Non-asymptotic information theory
  • Packet networks
  • Piecewise memoryless channels
  • Universal channel coding

ASJC Scopus subject areas

  • Computer Science(all)


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