With　the　rapid　growth　of　Internet　traffic　and　smart　mobile　terminals,　ultradense　networks　are　adopted　as　the　key　technology　of　the　fifth　generation　to　enhance　resource　utilization　and　content　distribution　while　causing　serious　energy　efficiency　problem.　Mobile　edge　computing　has　recently　drawn　great　attention　for　its　advantages　in　reducing　transmission　delay　and　network　energy　consumption　by　implementing　caching　and　computing　abilities　at　the　edge　of　mobile　networks.　To　improve　network　energy　efficiency　and　content　transmission,　in　this　paper,　we　propose　a　novel　energy-efficient　hierarchical　collaborative　scheme　by　considering　the　in-network　caching,　request　aggregation,　and　joint　allocation　of　caching,　computing,　and　communication　resources　in　a　layered　heterogeneous　network　including　mobile　users,　small　base　stations,　macro　base　stations,　and　the　cloud.　We　formulate　the　energy　consumption　problem　as　a　queuing　theory-based　centralized　model,　where　the　same　content　requests　can　be　aggregated　in　the　queue　of　each　base　station.　Then,　the　optimal　solution　is　analyzed　based　on　the　distribution　characteristic　of　content　popularity　at　the　base　stations.　Simulation　results　show　that　the　performance　of　our　proposed　model　is　much　better　than　the　existing　cloud-edge　cooperation　solutions　without　considering　the　deployment　of　caching　resource　and　request　aggregation　policies.　©　2022　Chao　Fang　et　al.