## 1 Introduction  
Satellite communications have the advantages of wide coverage, high flexibility, and large communication capacity and can avoid the adverse effects of terrain and other factors, supporting real-time, high-quality, and reliable communications in the fields of military, aviation, navigation, and scientific research. Satellite communication will play an important role in the next generation of wireless communication systems [1]. Satellites can be categorized into different types based on their orbital altitudes: low-Earth-orbit (LEO) satellites, medium-Earth-orbit (MEO) satellites, and geostationary orbit (GEO) satellites. Among these, large-scale LEO satellite communication networks, consisting of hundreds or even thousands of LEO satellites with lower orbital altitudes, are designed to provide high-speed broadband Internet connectivity [2]. Large-scale LEO satellite communication networks can offer smaller end-to-end latencies, thus supporting real-time multimedia applications, presenting a broad scope for development [3]. Compared to terrestrial communication networks, large-scale LEO satellite communication networks have many distinctive features [4]. The spatial scale of satellite communication networks is vast, with limited computing and forwarding capacities [5]. Fortunately, with the advancement of laser communication technology, establishing reliable, high-speed inter-satellite links (ISLs) have become feasible [6]. The propagation delay between LEO satellites is typically in the tens of milliseconds range [7]. Compared to terrestrial networks, large-scale low-Earth-orbit satellite communication networks exhibit higher propagation delays, and their spatial topology presents periodic variability, which results in periodic changes in propagation delay [8]. Furthermore, new traffic flows are continuously injected into the network, resulting in constant changes in the load on the output ports of the nodes within the network. A schematic of a large-scale LEO satellite communication network is shown in Figure 1.  
Time-Sensitive Networking (TSN) defines a series of IEEE standards that enhance the capabilities of traditional Ethernet, enabling it to support real-time and low-latency data transmission needs. Currently, its applications have expanded to multiple fields, providing critical network infrastructure support across various industries [9]. Traditional network technologies often struggle to meet the strict requirements for synchronicity, low latency, and high reliability in the aerospace sector. Moreover, the orbital altitude of GEO satellites is 35,786 km, that of MEO satellites ranges from 2000 to 20,000 km, and that of LEO satellites ranges from 500 to 2000 km. The length of an ISL between two satellites can be seen in Figure 2. The average Earth radius is denoted by \(R_{E}\). \(h_{A}\) and \(h_{B}\) are the orbital altitudes of satellites A and B, respectively, and \((\lambda_{1},\varphi_{1})\) and \((\lambda_{2},\varphi_{2})\) are the sub-satellite point longitudes and latitudes of satellites A and B, respectively. Then, the length of the ISL can be calculated using Equation (1):  
\[d_{AB}=\sqrt{\left(R_{E}+h_{A}\right)^{2}+\left(R_{E}+h_{B}\right)^{2}-2(R_{E} +h_{A})(R_{E}+h_{B})\cos(\theta)} \tag{1}\]  
where \(\theta\) is the angle between satellites A and B as seen from the center of the Earth. This angle can be calculated from the longitudes and latitudes of the sub-satellite points:  
\[\cos(\theta)=\sin(\phi_{1})\sin(\phi_{2})+\cos(\phi_{1})\cos(\phi_{2})\cos( \lambda_{2}-\lambda_{1}) \tag{2}\]  
Figure 1: Large-scale LEO satellite communication network architecture. From Equations (1) and (2), it can be seen that the length of the ISL increases with the increase in the satellite orbital altitude when \(\theta\) is fixed. In GEO and MEO satellite communication networks, the high orbital altitudes of the satellites result in longer ISLs, thereby leading to longer propagation delays. Therefore, the demand for low-latency data transmission for time-sensitive services cannot be met.