Achievable rates and error exponents for a class of mismatched compound channels

This paper investigates achievable information rates and error exponents of mismatched decoding when the channel belongs to the class of channels that are close to the decoding metric in terms of relative entropy. For both discrete- and continuous-alphabet channels, we derive approximations of the w...

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Detalhes bibliográficos
Autores: Patel, Priyanka, Molina Oliveras, Francesc|||0000-0002-3188-5599, Guillén Fàbregas, Albert|||0000-0003-2795-1124
Formato: artículo
Fecha de publicación:2025
País:España
Recursos:Universitat Politècnica de Catalunya (UPC)
Repositorio:UPCommons. Portal del coneixement obert de la UPC
Idioma:inglés
OAI Identifier:oai:upcommons.upc.edu:2117/444814
Acesso em linha:https://hdl.handle.net/2117/444814
https://dx.doi.org/10.1109/TIT.2025.3574460
Access Level:acceso abierto
Palavra-chave:Information theory
Mismatched decoding
Achievable rates
Error exponents
Relative entropy
Channel uncertainty
Discrete and continuous channels
Imperfect channel estimation
Modulo-additive noise
Nearest neighbor decoding
Descrição
Resumo:This paper investigates achievable information rates and error exponents of mismatched decoding when the channel belongs to the class of channels that are close to the decoding metric in terms of relative entropy. For both discrete- and continuous-alphabet channels, we derive approximations of the worst-case achievable information rates and error exponents as a function of the radius of a small relative entropy ball centered at the decoding metric, allowing the characterization of the loss incurred due to imperfect channel estimation. We provide a number of examples including symmetric metrics and modulo-additive noise metrics for discrete systems, and nearest neighbor decoding for continuous-alphabet channels, where we derive the approximation when the channel admits arbitrary statistics and when it is assumed noise-additive with unknown finite second-order moment.