Power Allocation and User Scheduling for Multibeam Satellites in Different Relay Scenarios

Abstract

In the case of advanced multibeam satellite equipped with phased array antenna, a large number of users can be effectively served by beamforming narrow spotbeams and managing interbeam interference. The scheme investigated in [1] chooses a better signal path between the direct communication from a satellite to a user and the indirect communication via ground stations. Transmission diversity to improve reliability and throughput is considered by scheduling based on channel conditions and potential interbeam interference. The simulation of [1] considers 25 users/gateway on the 5 by 5 planar grid, and the maximum number of active beams is 20. The user/gateway is located at one point of the grid. All the 25 users are assumed in the moderately rain weather channel condition of the Ka band [2]. In this study, we consider some scenarios of operating ground stations to provide better than [1]. In the first scenario, the position of ground station is fixed. In that case, we cannot guarantee that the channel condition of ground station would be better than others. Next, among multiple ground station candidates, we choose one to have good channel state quality. In the second scenario, we evaluate different simulation setups of user scheduling from those of [1]. For example, we expand the number of users and ground stations. By simulating each scenario, we show which one has better performance by comparing this paper’s results and the simulation results of [1]. In the third scenario simulation, we show how much weather effect influence increasing whole throughput. When ground station equipment would be installed to relay signals for worse channel states users, weather condition has to be considered to increase throughput in conclusion. In emergency situation such as earthquake, tsunami, etc., relay signals of ground station would help rescuers to connect each other. When rescuers attempt to set a temporary ground station up, they have to consider weather condition to increase throughput. ⓒ 2015 DGIST