Multi-Satellite Beam Hopping Based on Load Balancing and Interference Avoidance for NGSO Satellite Communication Systems

Due to the non-uniform distribution of the ground traffic demand and the high mobility of non-geostationary orbit (NGSO) satellites, how to make full use of the limited beam resources to serve users flexibly and efficiently is a brand-new challenge for NGSO communication systems. In order to achieve efficient spectrum utilization, the combination of full frequency multiplexing and beam hopping is a major trend in future satellite communication systems. However, conventional beam hopping methods are mainly based on geostationary satellites, which do not take into account the interference between satellites. This paper proposes a multi-satellite beam hopping algorithm based on load balancing and interference avoidance, which takes advantage of the multiple coverage features in the NGSO constellation and avoids intra-satellite interference and inter-satellite interference by designing beam-hopping patterns with spatial isolation characteristics. In particular, we decompose the multi-satellite beam hopping problem into three sub-problems, which are the multi-satellite load balancing problem, the single-satellite beam hopping pattern design problem, and the multi-satellite interference avoidance problem. Simulation results demonstrate that the proposed method reduces the load gap among satellites by about 72.5% and the average traffic satisfaction rate can reach 81.4%. Besides, our method has the lowest unmet capacity compared with other benchmarks, achieving better offered-requested data match.

I. Introduction

Satellite communication systems have the advantage of wide coverage and low construction cost, which is the trend of next-generation communication systems [1], [2], [3], [4]. Recently, non-geostationary orbit (NGSO) constellations have developed rapidly, such as Oneweb, Starlink, Telesat, etc [5]. In order to provide broadband transmission and seamless coverage, the NGSO constellation needs to achieve multiple coverage, that is, some areas are covered by multiple satellites. In addition, due to the non-uniform geographic distribution of the ground users and high mobility of NGSO satellites, the traffic demands in the area seen by the satellite show temporal and spatial non-uniformity. Therefore, how to make full use of the feature of multiple coverage to match limited satellite resources to non-uniform services is a major challenge for NGSO satellite systems [6], [7].