Publication:
Exploiting reconfigurable intelligent surfaces in edge caching: joint hybrid beamforming and content placement optimization

dc.contributor.coauthorChen, Yingyang
dc.contributor.coauthorWen, Miaowen
dc.contributor.coauthorWu, Yik-Chung
dc.contributor.coauthorWang, Li
dc.contributor.coauthorLiu, Weiping
dc.contributor.departmentDepartment of Electrical and Electronics Engineering
dc.contributor.kuauthorBaşar, Ertuğrul
dc.contributor.schoolcollegeinstituteCollege of Engineering
dc.date.accessioned2024-11-09T11:59:41Z
dc.date.issued2021
dc.description.abstractEdge caching can effectively reduce backhaul burden at core network and increase quality-of-service at wireless edge nodes. However, the beneficial role of edge caching cannot be fully realized when the offloading link is in deep fade. Fortunately, the impairments induced by wireless propagation environments could be renovated by a reconfigurable intelligent surface (RIS). In this paper, a new RIS-aided edge caching system is proposed, where a network cost minimization problem is formulated to optimize content placement at cache units, active beamforming at base station and passive phase shifting at RIS. After decoupling the content placement subproblem with the hybrid beamforming design, we propose an alternating optimization algorithm to tackle the active beamforming and passive phase shifting. For active beamforming, we transfer the problem into a semidefinite programming (SDP) and prove that the optimal solution of SDP is always rank-one. For passive phase shifting, we introduce the block coordinate descent method to alternately optimize the auxiliary variables and the RIS phase shifts. Further, a conjugate gradient algorithm based on manifold optimization is proposed to deal with the non-convex unit-modulus constraints. Numerical results show that our RIS-aided edge caching design can effectively decrease the network cost by improving the quality of offloading links.
dc.description.fulltextYES
dc.description.indexedbyWOS
dc.description.indexedbyScopus
dc.description.issue12
dc.description.openaccessYES
dc.description.publisherscopeInternational
dc.description.sponsoredbyTubitakEuTÜBİTAK
dc.description.sponsorshipNational Nature Science Foundation of China
dc.description.sponsorshipNatural Science Foundation of Guangdong Province
dc.description.sponsorshipFundamental Research Funds for the Central Universities
dc.description.sponsorshipNational Key Research and Development Program of China
dc.description.sponsorshipBeijing Municipal Natural Science Foundation
dc.description.sponsorshipScientific and Technological Research Council of Turkey (TÜBİTAK)
dc.description.versionAuthor's final manuscript
dc.description.volume20
dc.identifier.doi10.1109/TWC.2021.3087912
dc.identifier.eissn1558-2248
dc.identifier.embargoNO
dc.identifier.filenameinventorynoIR03167
dc.identifier.issn1536-1276
dc.identifier.quartileQ1
dc.identifier.scopus2-s2.0-85112149059
dc.identifier.urihttps://doi.org/10.1109/TWC.2021.3087912
dc.identifier.wos728926400010
dc.keywordsBeamforming
dc.keywordsEdge caching
dc.keywordsManifold optimization
dc.keywordsNetwork cost
dc.keywordsReconfigurable intelligent surface (RIS)
dc.language.isoeng
dc.publisherInstitute of Electrical and Electronics Engineers (IEEE)
dc.relation.grantno61871190
dc.relation.grantno61871416
dc.relation.grantno62001191
dc.relation.grantnoU2066201
dc.relation.grantno2018B030306005
dc.relation.grantno21620351
dc.relation.grantno2020YFC1511801
dc.relation.grantnoL192030
dc.relation.grantno120E401
dc.relation.ispartofIEEE Transactions on Wireless Communications
dc.relation.urihttp://cdm21054.contentdm.oclc.org/cdm/ref/collection/IR/id/9806
dc.subjectEngineering
dc.subjectTelecommunications
dc.titleExploiting reconfigurable intelligent surfaces in edge caching: joint hybrid beamforming and content placement optimization
dc.typeJournal Article
dspace.entity.typePublication
local.contributor.kuauthorBaşar, Ertuğrul
local.publication.orgunit1College of Engineering
local.publication.orgunit2Department of Electrical and Electronics Engineering
relation.isOrgUnitOfPublication21598063-a7c5-420d-91ba-0cc9b2db0ea0
relation.isOrgUnitOfPublication.latestForDiscovery21598063-a7c5-420d-91ba-0cc9b2db0ea0
relation.isParentOrgUnitOfPublication8e756b23-2d4a-4ce8-b1b3-62c794a8c164
relation.isParentOrgUnitOfPublication.latestForDiscovery8e756b23-2d4a-4ce8-b1b3-62c794a8c164

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