关键词: 低轨卫星, 跳波束技术, 干扰抑制, QoS均衡

Abstract: In the low earth orbit satellite (LEO) network, the communication services are unevenly distributed, and multiple satellites divide the terrestrial area into various cells according to the beam size. Existing research focuses on inter-satellite traffic balancing and frequency separation, but the problems of quality of service (QoS) imbalance and inter-satellite interference are becoming more and more prominent with the surge of demand and the shortage of spectrum. Thus, this paper proposes a multiple LEO-beam hopping (BH) satellite network in a spectrum-sharing scenario, it can enhance the quality of service (QoS) through inter-satellite QoS balancing and interference suppression. Cells with different types of services (e.g., video, voice, and IoT) have varying priority levels, and each cell should be allocated at least one-time slot in a BH time window. Therefore, we propose a cell quality equalization (CQE) algorithm to cluster inter-satellite cells. The algorithm initially defines a loss function to evaluate the fairness of inter-satellite service, then introduces random perturbation to increase the diversity of cell clusters, and finally determines the clustering result through a finite number of iterations. Since multiple satellites share the spectrum, severe inter-satellite interference diminishes cells' QoS. Therefore, we introduce a dynamic interference suppression (DIS) algorithm. The DIS algorithm first mitigates inter-satellite interference by nonlinearly adjusting transmit power, and it implements stronger interference suppression by controlling beam access when power adjustment fails to suppress the interference effectively. Compared with the maximum elevation angle algorithm, the CQE algorithm reduces the inter-satellite QoS gap by 70% and achieves QoS balancing. Compared with no interstellar interference suppression, the DIS algorithm ensures that the inter-satellite interference is always below the interference threshold, and it ultimately improves the QoS level. The DIS algorithm doubles the QoS at the interference threshold of -127 dBW.

Key words: LEO satellite, BH technology, interference suppression, QoS balancing