{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T03:03:28Z","timestamp":1760238208738,"version":"build-2065373602"},"reference-count":48,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2022,7,11]],"date-time":"2022-07-11T00:00:00Z","timestamp":1657497600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Key Research and Development Program of China","award":["2019YFE0113200","2019YFE0196600","TC20210519013"],"award-info":[{"award-number":["2019YFE0113200","2019YFE0196600","TC20210519013"]}]},{"name":"Tsinghua University-China Mobile Communications Group Co.,Ltd","award":["2019YFE0113200","2019YFE0196600","TC20210519013"],"award-info":[{"award-number":["2019YFE0113200","2019YFE0196600","TC20210519013"]}]},{"name":"Huawei Company Cooperation Project","award":["2019YFE0113200","2019YFE0196600","TC20210519013"],"award-info":[{"award-number":["2019YFE0113200","2019YFE0196600","TC20210519013"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Entropy"],"abstract":"<jats:p>The timely delivery of status information collected from sensors is critical in many real-time applications, e.g., monitoring and control. In this paper, we consider a scenario where a wireless sensor sends updates to the destination over an erasure channel with the supply of harvested energy and reliable backup energy. We adopt the metric age of information (AoI) to measure the timeliness of the received updates at the destination. We aim to find the optimal information updating policy that minimizes the time-average weighted sum of the AoI and the reliable backup energy cost. First, when all the environmental statistics are assumed to be known, the optimal information updating policy exists and is proved to have a threshold structure. Based on this special structure, an algorithm for efficiently computing the optimal policy is proposed. Then, for the unknown environment, a learning-based algorithm is employed to find a near-optimal policy. The simulation results verify the correctness of the theoretical derivation and the effectiveness of the proposed method.<\/jats:p>","DOI":"10.3390\/e24070961","type":"journal-article","created":{"date-parts":[[2022,7,11]],"date-time":"2022-07-11T21:57:53Z","timestamp":1657576673000},"page":"961","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Optimal Information Update for Energy Harvesting Sensor with Reliable Backup Energy"],"prefix":"10.3390","volume":"24","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6082-3311","authenticated-orcid":false,"given":"Lixin","family":"Wang","sequence":"first","affiliation":[{"name":"Department of Electronic Engineering, Tsinghua University, Beijing 100084, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5819-785X","authenticated-orcid":false,"given":"Fuzhou","family":"Peng","sequence":"additional","affiliation":[{"name":"School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510006, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9800-6472","authenticated-orcid":false,"given":"Xiang","family":"Chen","sequence":"additional","affiliation":[{"name":"School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510006, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3307-0067","authenticated-orcid":false,"given":"Shidong","family":"Zhou","sequence":"additional","affiliation":[{"name":"Department of Electronic Engineering, Tsinghua University, Beijing 100084, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2022,7,11]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Kaul, S., Yates, R., and Gruteser, M. 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