Deployment for High Altitude Platform Systems With Perturbation: Distributionally Robust Optimization Approach

In this letter, we consider a high altitude platform (HAP) system with perturbation caused by inevitable short-term airflow. However, such a HAP perturbation will lead to a decrease in the Quality-of-Service (QoS). To address this issue, we maximize the system sum-rate by jointly optimizing the location of HAP and the beamformer in the presence of HAP perturbation. We formulate a distributionally robust optimization problem under an information transmission chance constraint to tackle the perturbation. To solve this non-convex problem, we decouple it into two subproblems: location optimization subproblem and beamformer design subproblem, and then employ the Conditional Value-at-Risk (CVaR) based method to find the solutions. Simulation results show that the proposed scheme can achieve a better performance than the non-robust scheme.