This paper investigates a unmanned aerial vehicle(UAV)deployment problem in a non-orthogonal multiple access(NOMA)system,where the UAV is deployed as an aerial mobile base station to transmit data to two ground users....This paper investigates a unmanned aerial vehicle(UAV)deployment problem in a non-orthogonal multiple access(NOMA)system,where the UAV is deployed as an aerial mobile base station to transmit data to two ground users.An optimization problem is formulated by deploying the UAV for maximizing the sum rate of the two users.In order to solve the optimization problem,the feasible solution region is first reduced to a line segment between two users.Then,the optimization problem is simplified to a univariate problem,which can be solved by derivation under a certain situation,and the corresponding analytical solution is also provided.Moreover,a generalized algorithm,which considers 2 situations,is proposed to further determine the optimal UAV’s location.Specifically,four cases are discussed in the first situation.Extensive simulations are depicted to demonstrate effectiveness of the proposed algorithm and its superiority over the benchmarks in maximizing the two users’sum rate.展开更多
Due to its high mobility and flexible deployment,unmanned aerial vehicle(UAV)is drawing unprecedented interest in both military and civil applications to enable agile and ubiquitous connectivity.Mainly operating in an...Due to its high mobility and flexible deployment,unmanned aerial vehicle(UAV)is drawing unprecedented interest in both military and civil applications to enable agile and ubiquitous connectivity.Mainly operating in an open environment,UAV communications benefit from dominant line-of-sight links;however,this on the other hand renders the communications more vulnerable to malicious attacks.Recently,physical layer security(PLS)has been introduced to UAV systems as an important complement to the conventional cryptography-based approaches.In this paper,a comprehensive survey on the current achievements of UAV-PLS is conducted.We first introduce the basic concepts including typical static/-mobile UAV deployment scenarios,the unique air-toground channel and aerial nodes distribution models,as well as various roles that a UAV may act when PLS is concerned.Then,we start by reviewing the secrecy performance analysis and enhancing techniques for statically deployed UAV systems,and extend the discussion to the more general scenario where the UAVs’mobility is further exploited.For both cases,respectively,we summarize the commonly adopted methodologies,then describe important works in the litera ture in detail.Finally,potential research directions and challenges are discussed to provide an outlook for future works in the area of UAV-PLS.展开更多
Unmanned aerial vehicle base stations(UAV-BSs)can provide a fast network deployment scheme for heterogeneous networks.However,unmanned aerial vehicle(UAV)has limited capability and cannot assist the base station(BS)we...Unmanned aerial vehicle base stations(UAV-BSs)can provide a fast network deployment scheme for heterogeneous networks.However,unmanned aerial vehicle(UAV)has limited capability and cannot assist the base station(BS)well.The ability of a UAV to assist the BSs is limited,and the cluster deployment relies on the leading UAV.The dispersive deployment of multiple UAVs(multi-UAVs)need a macro base station(MBS)to determine their positions to prevent collisions or interference.Therefore,a distributed cooperative deployment scheme is proposed for UAVs to solve this problem.The scheme can increase the ability of UAVs to assist users and reduce the pressure on BSs to deploy UAVs.Firstly,the randomly distributed users are pre-clustered.Then the placement problem was modeled as a circle expansion problem and a pre-clustering radius expansion algorithm was proposed.Under the constraint of users'data rates,it provides services for more users.Finally,the proposed algorithm was compared with the density-aware placement algorithm.The simulation results show that the proposed algorithm can provide services for more users and improve the coverage rate of users while ensuring the data rates.展开更多
基金the National Natural Science Foundation of China(No.61702258,61901211)the Natural Science Foundation of Jiangsu Province(No.BK20170766).
文摘This paper investigates a unmanned aerial vehicle(UAV)deployment problem in a non-orthogonal multiple access(NOMA)system,where the UAV is deployed as an aerial mobile base station to transmit data to two ground users.An optimization problem is formulated by deploying the UAV for maximizing the sum rate of the two users.In order to solve the optimization problem,the feasible solution region is first reduced to a line segment between two users.Then,the optimization problem is simplified to a univariate problem,which can be solved by derivation under a certain situation,and the corresponding analytical solution is also provided.Moreover,a generalized algorithm,which considers 2 situations,is proposed to further determine the optimal UAV’s location.Specifically,four cases are discussed in the first situation.Extensive simulations are depicted to demonstrate effectiveness of the proposed algorithm and its superiority over the benchmarks in maximizing the two users’sum rate.
基金supported in part by the National Key Research and Development Program of China under Grant 2020YFA0711301in part by the National Natural Science Foundation of China under Grant 61922049,61941104,61921004,62171240,61771264,62001254,61801248,61971467+2 种基金the Key Research and Development Program of Shandong Province under Grant 2020CXGC010108the Key Research and Development Program of Jiangsu Province of China under Grant BE2021013-1the Science and Technology Program of Nantong under Grants JC2021121,JC2021017。
文摘Due to its high mobility and flexible deployment,unmanned aerial vehicle(UAV)is drawing unprecedented interest in both military and civil applications to enable agile and ubiquitous connectivity.Mainly operating in an open environment,UAV communications benefit from dominant line-of-sight links;however,this on the other hand renders the communications more vulnerable to malicious attacks.Recently,physical layer security(PLS)has been introduced to UAV systems as an important complement to the conventional cryptography-based approaches.In this paper,a comprehensive survey on the current achievements of UAV-PLS is conducted.We first introduce the basic concepts including typical static/-mobile UAV deployment scenarios,the unique air-toground channel and aerial nodes distribution models,as well as various roles that a UAV may act when PLS is concerned.Then,we start by reviewing the secrecy performance analysis and enhancing techniques for statically deployed UAV systems,and extend the discussion to the more general scenario where the UAVs’mobility is further exploited.For both cases,respectively,we summarize the commonly adopted methodologies,then describe important works in the litera ture in detail.Finally,potential research directions and challenges are discussed to provide an outlook for future works in the area of UAV-PLS.
基金supported by the National Natural Science Foundation of China(61771070,61671088)。
文摘Unmanned aerial vehicle base stations(UAV-BSs)can provide a fast network deployment scheme for heterogeneous networks.However,unmanned aerial vehicle(UAV)has limited capability and cannot assist the base station(BS)well.The ability of a UAV to assist the BSs is limited,and the cluster deployment relies on the leading UAV.The dispersive deployment of multiple UAVs(multi-UAVs)need a macro base station(MBS)to determine their positions to prevent collisions or interference.Therefore,a distributed cooperative deployment scheme is proposed for UAVs to solve this problem.The scheme can increase the ability of UAVs to assist users and reduce the pressure on BSs to deploy UAVs.Firstly,the randomly distributed users are pre-clustered.Then the placement problem was modeled as a circle expansion problem and a pre-clustering radius expansion algorithm was proposed.Under the constraint of users'data rates,it provides services for more users.Finally,the proposed algorithm was compared with the density-aware placement algorithm.The simulation results show that the proposed algorithm can provide services for more users and improve the coverage rate of users while ensuring the data rates.
