A Muti-beam Placement Optimization Scheme in LEO Beam Hopping Satellite Systems.

Beam hopping (BH) technology has emerged as a solution for low earth orbit (LEO) satellite communication system to better utilize the limited resources onboard. This technology serves the region with fewer but flexible spot beams which dynamically point to users based on their location and traffic needs by taking advantage of phased array antenna. However, in some cases, some of the users are located at the edge of the beam and a large number of beams waiting to be served, resulting in unsatisfactory user channel quality and long queuing delay. In response, we formulated a multi-beam placement problem to jointly optimize beam placement and utilization efficiency of satellite resources. Then we proposed an algorithm based on density clustering to solve the problem and assign all users to different beam footprints according to their geographic location with low complexity. Each beam footprint will be served by a beam according to the BH schedule afterwards. Finally we present the evaluation of the proposed scheme from different aspects. Simulation results indicate that compared with other benchmark schemes, the proposed one is more superior in improving the system throughput and reducing the average queuing delay.