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| \ Unmanned \ aerial \ vehicles (UAVs) have attracted great interest \ in \ emergency communications application due to their high mobility, flexible deployment。In this paper, we \ study \ the \ effective deployment of multiple UAVs that act as aerial \ base \ stations to provide communication services to indoor users in emergency scenarios.To this end,this paper presents \ the \ problem \ of jointly optimizing \ indoor \ user \ association, \ bandwidth \ allocation, and \ 3D placement of UAVs,aiming to maximize the minimum throughput of all indoor users in uplink to improve user fairness. The problem is a challenging mixed integer non-convex optimization \ problem , \ and thus this paper proposes \ an \ efficient \ iterative \ algorithm, the joint user-UAV association, \ bandwidth \ allocation, \quad and \ placement \ optimization \ based \ on \ least \ squares \ gradient \ estimation (JABP-LSGE) algorithm , to solve the problem using LSGE \ estimation \ and \quad continuous \quad convex optimization techniques. Specifically, integer linear programming \ is \ used \ to \ obtain \quad indoor \ user \ association \ scheduling , convex \ optimization \ is used to achieve \quad bandwidth \ allocation, and LSGE \ is \ used \ to \ update \ the \ UAV \ 3D \ placement. Simulation \quad results \ show that \ the \ JABP-LSGE \ algorithm \ can improve \quad user \quad uplink throughput \quad more effectively \ and take better care of the fairness of each user than \quad other traditional methods. |
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| Keywords:Communication and Information System, Unmanned Aerial Vehicles (UAV) Communication, Throughput Maximization, Joint Optimization, Placement Layout |
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