Joint 3-D Position Deployment and Traffic Offloading for Caching and Computing-Enabled UAV Under Asymmetric Information.

To offload the rapidly increasing video traffic in the Internet of Things (IoT), the caching and computing-enabled unmanned aerial vehicles (UAVs) have become a paradigm in alleviating the pressure of wireless backhauls of the mobile network operator (MNO) and improving the Quality of Service (QoS) of subscribers of content providers (CPs), especially, in the situations where fixedly deployed small-cell base stations (SBSs) are not applicable. However, the resources in the UAV are costly and limited, while rational CPs are reluctant to reveal their willingness of leasing. Taking such asymmetric information into consideration, the problem that how the MNO leases the caching and computing resources to different CPs is formulated into a contract design problem, in which the UAV’s 3-D position deployment is also involved. To find the optimal solutions, the proposed problem is decoupled into two subproblems. In the position deployment subproblem, the 3-D position of the UAV is analyzed, and the hovering height and coverage radius are jointly optimized to maximize the offloading volume during the life of the UAV. With the derived optimal position of the UAV, the individual rationality (IR) and incentive compatibility (IC) constraints in the contract design subproblem are simplified, and a low complexity algorithm based on the alternating direction method of multipliers (ADMMs) is proposed to find the optimal contract. Finally, the effectiveness of the proposed scheme is verified by simulation, and a comparative analysis is carried out in terms of save latency, saved bandwidth and utility.