## 1 Introduction
Traditional satellite communication ground station systems [6] are implemented in a chimney-like, static manner, using specialized hardware and software, and they have the following flaws and restrictions: First, poor flexibility, which cannot be expanded according to business requirements when new satellites or constellations are launched; second, the traditional ground station lacks openness, as most of the equipment employs private hardware and software interfaces, and the ground station hardware system is strongly coupled with specialized proprietary software that limits innovations to and the evolution of the system; in addition, the closed technology leads to long cycles of service interruption and low operational efficiency [7]; third, because traditional ground stations only perform one function and each set of equipment can only be used with a specific constellation's technical system, different technology regimes require multiple ground stations, so the traditional ground station architecture is complicated and expensive to build, operate, and \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Architecture**} & **Where to Process** & \multirow{2}{*}{**Transmission Delay**} & \multirow{2}{*}{**Deployment Time**} & **Considers Limitations of** \\  & **Signal and Data** & & & **Satellite Resources** \\ \hline MEO satellites [2] and 5G NTN [3] & Processing by ground & & & Long & No \\ \hline IoT in future NTN [5] & Processing on satellite & Short & Short & No \\ \hline Satellite–ground & & & & & \\ network for 6G [4] \# & Processing on satellite & Short & Short & Yes \\ \hline Architecture proposed & & & & \\ in this paper & & & & \\ \hline \hline \end{tabular}  
* This is a review article.  
\end{table} 
Table 1: Architecture Comparison. maintain [8]. Therefore, when traditional ground station technologies are adopted, it is hard to migrate the access network functions from the ground station systems up to the satellites. Since the advent of virtualization technology, software-defined networking (SDN) [9; 10; 11] has been used in the ICT sector to implement network operations and enable software system changes without the frequent replacement of hardware. The base station system must incorporate virtualization technology into the design process for the development of the next-generation satellite internet system [12], then gradually transition to a software-centric network design approach. We should decouple hardware and software to realize the satellite-borne base station [13] functions through software definition, provide satellite-borne base station services \"on demand\", and increase system flexibility. Then, it will be possible for us to migrate the ground station functions up to the satellites. In this paper, we build a multi-star joint digital base station system based on the idea of virtualization and software definition, which realizes RF digitization at the satellite antenna and implements RF front-end digital signal processing, baseband protocol software processing, and high-level protocol processing on the virtualized platform. The digital base station system realizes the decoupling of the base station's hardware and software, so the functions of the base station can be flexibly orchestrated and dynamically loaded by software. But, this also leads to another question, that is, how to deploy the network functions on the satellites quickly to avoid affecting the network performance when the nearby satellites move fast and the topology changes fast. Therefore, we propose a fast adaptive migration algorithm of network functions based on multi-dimensional environment awareness, adding the migration precomputation and real-time computation to build a fast architecture for digitized satellite-borne base station system networks and realize network function migration [14; 15; 16] while guaranteeing network load balancing and reducing the real-time computing overhead of the system network migration.