Performance Analysis in Satellite Communication With Beam Hopping Using Discrete-Time Queueing Theory

Satellite communication with beam hopping is a promising approach to meeting wide-area user traffic demands under on-board resource limitation. However, there is currently a lack of theoretical models that characterize the impact of beam hopping on user uplink transmission performance. In this article, two simplified beam hopping modes for satellite communication are proposed, namely, probabilistic beam hopping and deterministic beam hopping. Based on these two modes, two Markov chain models are established, which describe the states and state transitions of users. In the first model, the user state incorporates only user queue length, while the state in the second model considers both user queue length and time slot index. For both models, we first derive their steady-state probabilities and state transition probabilities, and then the steady-state probability of successful packet transmission is solved through a numerical method. Further, we theoretically derive the explicit expressions of various user performance metrics based on the steady-state probability of successful packet transmission, such as average throughput, buffer occupancy rate, packet loss rate, and transmission delay, and simulation results verify the correctness of all expressions. By simulation, it is shown that the minimum beam illumination probability or time length can be determined given specific performance requirements to guide system design, and there is an inflection point for the improvement in system performance with the increase of beam resource. Moreover, it is found that deterministic beam hopping achieves lower user delay compared to probabilistic beam hopping when the system is near to saturation.