{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T01:23:38Z","timestamp":1760145818640,"version":"build-2065373602"},"reference-count":36,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2024,8,23]],"date-time":"2024-08-23T00:00:00Z","timestamp":1724371200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"University of Oradea, Romania"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Entropy"],"abstract":"<jats:p>In this paper, new schemes have been proposed for the estimation of the additive white Gaussian noise (AWGN) channel with intersymbol interference (ISI) in an iterative equalization and decoding system using low-density parity check (LDPC) codes. This article explores the use of the least squares algorithm in various scenarios. For example, the impulse response of the AWGN channel h was initially estimated using a training sequence. Subsequently, the impulse response was calculated based on the training sequence and then re-estimated once using the sequence estimated from the output of the LDPC decoder. Lastly, the impulse response was calculated based on the training sequence and re-estimated twice using the sequence estimated from the output of the LDPC decoder. Comparisons were made between the performances of the three mentioned situations, with the situation in which a perfect estimate of the impulse response of the channel is assumed. The performance analysis focused on how the bit error rate changes in relation to the signal-to-noise ratio. The BER performance comes close to the scenario of having a perfect estimate of the impulse response when the estimation is performed based on the training sequence and then re-estimated twice from the sequence obtained from the output of the LDPC decoder.<\/jats:p>","DOI":"10.3390\/e26090720","type":"journal-article","created":{"date-parts":[[2024,8,26]],"date-time":"2024-08-26T03:59:09Z","timestamp":1724644749000},"page":"720","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Estimation of the Impulse Response of the AWGN Channel with ISI within an Iterative Equalization and Decoding System That Uses LDPC Codes"],"prefix":"10.3390","volume":"26","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-3585-8229","authenticated-orcid":false,"given":"Adriana-Maria","family":"Cuc","sequence":"first","affiliation":[{"name":"Faculty of Electrical Engineering and Information Technology, University of Oradea, 410087 Oradea, Romania"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4178-0376","authenticated-orcid":false,"given":"Florin Lucian","family":"Morgo\u0219","sequence":"additional","affiliation":[{"name":"Faculty of Electrical Engineering and Information Technology, University of Oradea, 410087 Oradea, Romania"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7615-8053","authenticated-orcid":false,"given":"Adriana-Marcela","family":"Grava","sequence":"additional","affiliation":[{"name":"Faculty of Electrical Engineering and Information Technology, University of Oradea, 410087 Oradea, Romania"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6316-1368","authenticated-orcid":false,"given":"Cristian","family":"Grava","sequence":"additional","affiliation":[{"name":"Faculty of Electrical Engineering and Information Technology, University of Oradea, 410087 Oradea, Romania"}]}],"member":"1968","published-online":{"date-parts":[[2024,8,23]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1749","DOI":"10.1016\/j.jksus.2020.01.012","article-title":"Suppression method of inter-symbol interference in communication system based on mathematical chaos theory","volume":"32","author":"Liang","year":"2020","journal-title":"J. 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