1,113 research outputs found
Joint Trajectory and Communication Design for UAV-Enabled Multiple Access
Unmanned aerial vehicles (UAVs) have attracted significant interest recently
in wireless communication due to their high maneuverability, flexible
deployment, and low cost. This paper studies a UAV-enabled wireless network
where the UAV is employed as an aerial mobile base station (BS) to serve a
group of users on the ground. To achieve fair performance among users, we
maximize the minimum throughput over all ground users by jointly optimizing the
multiuser communication scheduling and UAV trajectory over a finite horizon.
The formulated problem is shown to be a mixed integer non-convex optimization
problem that is difficult to solve in general. We thus propose an efficient
iterative algorithm by applying the block coordinate descent and successive
convex optimization techniques, which is guaranteed to converge to at least a
locally optimal solution. To achieve fast convergence and stable throughput, we
further propose a low-complexity initialization scheme for the UAV trajectory
design based on the simple circular trajectory. Extensive simulation results
are provided which show significant throughput gains of the proposed design as
compared to other benchmark schemes.Comment: Submitted for possible publicatio
Securing UAV Communications Via Trajectory Optimization
Unmanned aerial vehicle (UAV) communications has drawn significant interest
recently due to many advantages such as low cost, high mobility, and on-demand
deployment. This paper addresses the issue of physical-layer security in a UAV
communication system, where a UAV sends confidential information to a
legitimate receiver in the presence of a potential eavesdropper which are both
on the ground. We aim to maximize the secrecy rate of the system by jointly
optimizing the UAV's trajectory and transmit power over a finite horizon. In
contrast to the existing literature on wireless security with static nodes, we
exploit the mobility of the UAV in this paper to enhance the secrecy rate via a
new trajectory design. Although the formulated problem is non-convex and
challenging to solve, we propose an iterative algorithm to solve the problem
efficiently, based on the block coordinate descent and successive convex
optimization methods. Specifically, the UAV's transmit power and trajectory are
each optimized with the other fixed in an alternating manner until convergence.
Numerical results show that the proposed algorithm significantly improves the
secrecy rate of the UAV communication system, as compared to benchmark schemes
without transmit power control or trajectory optimization.Comment: Accepted by IEEE GLOBECOM 201
FROM WECHAT TO WE FIGHT: TENCENT AND CHINA MOBILE’S DILEMMA
With the coming of mobile internet era, Giants in the different industry begin to compete face by face. This teaching case presents the event of charging for WeChat in China context to delineate the new challenges that Online Service Provider and Mobile Network Operator will face. The case describes the origin of the event, development of WeChat from inception to today, the impact of WeChat on China Mobile growth, current dilemma and disputes that all stakeholders involved. This case can help students gain more insights on the current debate around Net Neutrality
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