An Upper Bound on the Reliability Function of the DMC with or without Mismatch

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We derive a new upper bound on the reliability function for channel coding over discrete memoryless channels. Our bounding technique relies on two main elements: (i) adding an auxiliary genie-receiver that reveals to the original receiver a list of codewords including the transmitted one, which satisfy a certain type property, and (ii) partitioning (most of) the list into subsets of codewords that satisfy a certain pairwise-symmetry property, which facilitates lower bounding of the average error probability by the pairwise error probability within a subset. We compare the obtained bound to the Shannon-Gallager-Berlekamp straight-line bound, the sphere-packing bound, and an amended version of Blahut's bound. Our bound is shown to be at least as tight for all rates, with cases of stricter tightness in a certain range of low rates, compared to all three aforementioned bounds. Our derivation is performed in a unified manner which is valid for any rate, as well as for a wide class of additive decoding metrics, whenever the corresponding zero-error capacity is zero. We also present a dual form of the bound, and discuss a looser bound of a simpler form, which is analyzed for the case of the binary symmetric channel with maximum likelihood decoding.

Original languageEnglish
Title of host publication2023 IEEE Information Theory Workshop, ITW 2023
PublisherInstitute of Electrical and Electronics Engineers Inc.
Number of pages6
ISBN (Electronic)9798350301496
StatePublished - 2023
Event2023 IEEE Information Theory Workshop, ITW 2023 - Saint-Malo, France
Duration: 23 Apr 202328 Apr 2023

Publication series

Name2023 IEEE Information Theory Workshop, ITW 2023


Conference2023 IEEE Information Theory Workshop, ITW 2023

Bibliographical note

Publisher Copyright:
© 2023 IEEE.


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