{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T02:09:12Z","timestamp":1760148552606,"version":"build-2065373602"},"reference-count":25,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2023,5,17]],"date-time":"2023-05-17T00:00:00Z","timestamp":1684281600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["62101442","61801382","62071377","2021JQ-705","2023-JC-YB-514","20210115","CXJJYL2022008"],"award-info":[{"award-number":["62101442","61801382","62071377","2021JQ-705","2023-JC-YB-514","20210115","CXJJYL2022008"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100007128","name":"Natural Science Foundation of Shaanxi Province","doi-asserted-by":"publisher","award":["62101442","61801382","62071377","2021JQ-705","2023-JC-YB-514","20210115","CXJJYL2022008"],"award-info":[{"award-number":["62101442","61801382","62071377","2021JQ-705","2023-JC-YB-514","20210115","CXJJYL2022008"]}],"id":[{"id":"10.13039\/501100007128","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Young Talent Fund of University Association for Science and Technology in Shaanxi","award":["62101442","61801382","62071377","2021JQ-705","2023-JC-YB-514","20210115","CXJJYL2022008"],"award-info":[{"award-number":["62101442","61801382","62071377","2021JQ-705","2023-JC-YB-514","20210115","CXJJYL2022008"]}]},{"name":"2022 Graduate Innovation Fund Project of Xi\u2019an University of Posts and Telecommunications of Shaanxi Province","award":["62101442","61801382","62071377","2021JQ-705","2023-JC-YB-514","20210115","CXJJYL2022008"],"award-info":[{"award-number":["62101442","61801382","62071377","2021JQ-705","2023-JC-YB-514","20210115","CXJJYL2022008"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>To allieviate the heavy traffic burden over backhaul links and improve the user\u2019s quality of service (QoS), edge caching plays an important role in wireless networks. This paper investigated the optimal designs of content placement and transmission in wireless caching networks. The contents to be cached and requested were encoded into individual layers by scalable video coding (SVC), and different sets of layers can provide different viewing qualities to end users. The demanded contents were provided by helpers caching the requested layers, or by the macro-cell base station (MBS) otherwise. In the content placement phase, this work formulated and solved the delay minimization problem. In the content transmission phase, the sum rate optimization problem was established. To effectively solve the nonconvex problem, the methods of semi-definite relaxation (SDR), successive convex approximation (SCA), and arithmetic-geometric mean (AGM) inequality were adopted, after which the original problem was transformed into the convex form. The numerical results show that the transmission delay is reduced by caching contents at helpers. Moreover, the fast convergence of the proposed algorithm for solving the sum rate maximization problem is presented, and the sum rate gain of edge caching is also revealed, as compared to the benchmark scheme without content caching.<\/jats:p>","DOI":"10.3390\/s23104823","type":"journal-article","created":{"date-parts":[[2023,5,18]],"date-time":"2023-05-18T07:03:58Z","timestamp":1684393438000},"page":"4823","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Optimal Designs of SVC-Based Content Placement and Delivery in Wireless Caching Networks"],"prefix":"10.3390","volume":"23","author":[{"given":"Xuewei","family":"Zhang","sequence":"first","affiliation":[{"name":"School of Communications and Information Engineering, Xi\u2019an University of Posts and Telecommunications, Xi\u2019an 710121, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Lin","family":"Zhang","sequence":"additional","affiliation":[{"name":"School of Communications and Information Engineering, Xi\u2019an University of Posts and Telecommunications, Xi\u2019an 710121, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2520-8388","authenticated-orcid":false,"given":"Yuan","family":"Ren","sequence":"additional","affiliation":[{"name":"School of Communications and Information Engineering, Xi\u2019an University of Posts and Telecommunications, Xi\u2019an 710121, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jing","family":"Jiang","sequence":"additional","affiliation":[{"name":"School of Communications and Information Engineering, Xi\u2019an University of Posts and Telecommunications, Xi\u2019an 710121, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Junxuan","family":"Wang","sequence":"additional","affiliation":[{"name":"School of Communications and Information Engineering, Xi\u2019an University of Posts and Telecommunications, Xi\u2019an 710121, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2023,5,17]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"131","DOI":"10.1109\/MCOM.2014.6736753","article-title":"Cache in the air: Exploiting content caching and delivery techniques for 5G systems","volume":"52","author":"Wang","year":"2014","journal-title":"IEEE Commun. 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