Path conflict avoidance scheme based on topology switching and traffic distribution awareness in optical satellite networks

Laser communication, with advantages in transmission distance, capacity, confidentiality, and anti-interference, has become a key development direction for future satellite communications, especially inter-satellite communications. However, satellite user service demands are unevenly distributed, with service hotspots mostly in the northern hemisphere, leading to traffic aggregation in developed areas. This issue is more prominent in low Earth orbit (LEO) constellations due to the large number of satellites and small ground service coverage. Therefore, effective routing algorithms are needed to alleviate congestion caused by traffic aggregation. In this paper, an advance planning-path conflict avoidance (AP-PCA) algorithm based on topology switching and traffic distribution awareness is proposed to avoid path conflict, considering the impact of dynamic topology switching and the performance difference of satellite–ground links. The influence of other original source–destination node pairs on critical links in the calculation of link weights to avoid conflicts in path selection is also considered. Compared with the three benchmark algorithms, the simulation results verify that our proposed solution reduces the blocking probability of traffic requests while ensuring the transmission delay and bandwidth utilization.