INTRODUCTION

Since the 1990s, the low-orbit constellation project, represented by Iridium and Globalstar, has ushered in the first-generation low-orbit constellation network’s development wave. However, due to the inability to compete with the rapidly developing terrestrial network and commercial operation strategy errors, these plans ultimately failed [1]. In recent years, the enormous constellation projects, such as Starlink [2] and OneWeb [3], have propelled a new wave of low-orbit mega-constellation network development [4]. The emerging low-orbit mega-constellation project [5] typically comprises hundreds to tens of thousands of low-orbit satellites, with the aim of providing global users with ubiquitous broadband Internet access services. The project features large-scale, wide coverage, low delay, and broadband capabilities, such as globalization and integration of space and earth.

自20世纪90年代以来，以 Iridium 和 Globalstar 为代表的低轨星座项目引领了第一代低轨星座网络的发展潮流。然而，由于难以与迅速发展的地面网络竞争以及商业运营策略失误，这些计划最终以失败告终 [1]。近年来，Starlink [2] 和 OneWeb [3] 等大规模星座项目的兴起推动了新一轮低轨超大型星座网络的发展 [4]。新兴的低轨超大型星座项目 [5] 通常由数百至数万颗低轨卫星组成，旨在为全球用户提供无处不在的宽带互联网接入服务。该项目具有大规模、广覆盖、低时延和高带宽等特点，实现了全球化及天地一体化的连接模式。

In the development of large-scale low-orbit satellite networks, the design and analysis of link connection are crucial tasks. Research has demonstrated [6] that increasing the capacity of the satellite topology can significantly reduce the delay between ground stations. Compared to the expensive hardware upgrades for inter-satellite links [7], designing the inter-satellite topology is a cost-effective approach to reduce the number of transmission hops, and lower the average transmission delay.

在大规模低轨卫星网络的发展过程中，链路连接的设计与分析是关键任务。研究表明 [6]，提高卫星拓扑结构的容量能够显著降低地面站之间的通信时延。相比于昂贵的星间链路硬件升级 [7]，优化星际拓扑结构是一种更具成本效益的方法，有助于减少传输跳数并降低平均传输时延。

A multitude of analyses [8]–[10] have utilized a gridbased networking approach, which is called +Grid [11]. In actuality, there exist almost a hundred inter-satellite links that each satellite can establish to maintain a stable long-term connection. In recent years, researchers [11] have incorporated graph theory motifs [12] to disrupt the traditional connection regulations, thus achieving reduced propagation delays and transmission hops. However, the previous optimization efforts have not taken into consideration the highly uneven distribution of users, which poses a significant contradiction with the uniform configuration of the satellite network. Driven by the distribution of users, this paper proposes a new largescale satellite network elastic link connection design, which is flexible and matches such uneven distribution of users.

众多研究 [8]–[10] 采用了基于网格的网络方法，即 +Grid [11]。实际上，每颗卫星可以建立近百条星间链路，以维持稳定的长期连接。近年来，研究人员 [11] 引入了图论模型 [12]，打破了传统的连接规则，从而降低了传播时延和传输跳数。然而，现有的优化方案并未充分考虑用户分布的不均衡性，而均匀配置的卫星网络与此存在显著矛盾。因此，本文提出了一种面向用户分布的大规模卫星网络弹性链路连接设计，以灵活匹配用户分布的不均衡特性。

In this work, we make the following contributions:

• We propose a link connection design for satellite network that matches the uneven distribution of users. Our solution is flexible and can be applied to different existing constellations.

• We propose the index of matching degree between topology structure and user distribution, which is used to evaluate the effectiveness of topology algorithm.

• We present the networking simulation based on real satellite constellation data and hops can be improved by as much as 41% at least.

本研究的主要贡献如下：

• 提出了一种 匹配用户分布不均衡性的卫星网络链路连接设计 ，该方案具备较高的灵活性，并可适用于不同的现有星座网络。
• 提出了 拓扑结构与用户分布的匹配度指标 ，用于评估拓扑算法的有效性。
• 基于真实卫星星座数据进行了组网仿真，结果表明，在多种场景下，该方案可将传输跳数至少减少 41%。

The rest of this paper is organized as follows: Section II summarizes and analyzes related work. Section III conducts modeling analysis on the networking problem and puts forward the optimization goal. Section IV describes the elastic link connection design and details the relevant algorithms. Section V carries out simulation experiments and comparative analysis of related work. Section VI summarizes the work and outlines future directions for research.

本文的结构安排如下：第 II 节总结并分析相关研究工作；第 III 节对网络问题进行建模分析，并提出优化目标；第 IV 节详细描述弹性链路连接设计及相关算法；第 V 节开展仿真实验，并对相关方法进行对比分析；第 VI 节总结本文研究成果，并展望未来研究方向。