Aiming　at　the　difference　of　users　in　different　time　periods　for　the　femto　base　station　(FBS),the　power　allocation　problem　of　maximizing　the　total　downlink　information　is　investigated.The　different　time　periods　include　busy　time　and　spare　time.There　are　more　users　in　the　busy　time　and　less　users　in　the　spare　time.By　deploying　a　pico　base　station　carried　by　unmanned　aerial　vehicle　(PBS-UAV),it　provides　services　for　users　of　multiple　FBSs　in　spare　time.Both　the　FBS　and　PBS-UAV　have　energy　harvesting　function.During　the　busy　time,the　FBS　and　PBS-UAV　simultaneously　harvest　energy　from　the　macro　base　station,and　FBSs　transmit　data　to　users.During　the　spare　time,multiple　FBSs　are　replaced　by　the　PBS-UAV　to　communicate　with　users　in　downlink.The　power　allocation　problem　is　modeled　as　an　optimization　problem.The　objective　is　to　maximize　the　amount　of　downlink　information　of　FBSs　and　PBS-UAV　while　satisfying　the　constraints　of　FBS　and　PBS-UAV　energy　consumption　and　transmission　power.Because　the　formulated　optimization　problem　is　a　convex　optimization　problem,the　optimal　solution　is　obtained　by　using　an　augmented　Lagrange　multiplier　method.Simulations　show　that　compared　with　the　equal　power　method　and　partial　fixed　power　method　with　PBS-UAV,the　proposed　method　has　an　increase　in　terms　of　total　information　to　different　degrees.　©　2020,　Editorial　Department　of　Journal　of　Beijing　University　of　Posts　and　Telecommunications.　All　right　reserved.