2026-04-14T03:38:36Zhttps://recercat.cat/oai/request

oai:recercat.cat:2117/4448142026-02-07T10:58:44Zcom_2072_1033col_2072_452950

Achievable rates and error exponents for a class of mismatched compound channels Patel, Priyanka Molina Oliveras, Francesc Guillén Fàbregas, Albert Universitat Politècnica de Catalunya. Departament de Teoria del Senyal i Comunicacions Universitat Politècnica de Catalunya. SPCOM - Processament del Senyal i Comunicacions 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 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. This work was supported in part by the European Research Council under Grants 725411 and 101142747, and in part by the Spanish Ministry of Economy and Competitiveness under Grant PID2020-116683GB-C22. Francesc Molina was also supported by a Margarita Salas Fellowship. Peer Reviewed Postprint (published version) 2025-05-28 Article Patel, P.; Molina, F.; Guillén, A. Achievable rates and error exponents for a class of mismatched compound channels. «IEEE transactions on information theory», 28 Maig 2025, vol. 71, núm. 9, p. 6895-6911. 0018-9448 https://arxiv.org/abs/2505.20523 https://hdl.handle.net/2117/444814 10.1109/TIT.2025.3574460 eng https://ieeexplore.ieee.org/document/11016808 info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2017-2020/PID2020-116683GB-C22/ES/GENERALIZED AND REFINED ASYMPTOTICS IN FINITE-BLOCKLENGTH INFORMATION THEORY: LAPLACE METHODS AND PROBABILISTIC MODULATION SHAPING FOR COMMUNICATIONS/ Open Access 17 p. application/pdf