Hybrid 10/100  Gbps laser inter-satellite link planning in optical satellite networks

With the continuously decreasing cost of launching satellites, low-Earth-orbit (LEO) optical satellite networks (OSNs) have emerged as an important research topic. By using laser communication, 10 Gbps laser inter-satellite links (LISLs) have been fully deployed, while 100 Gbps LISLs are rapidly advancing and are expected to become key components of future networks. With the expected growth in satellite-delivered service demand, OSNs will inevitably enter a hybrid stage in which 10 and 100 Gbps LISLs coexist. However, such coexistence may cause traffic bottlenecks of 10 Gbps LISLs and underutilization of 100 Gbps LISLs in LEO OSNs. From a network planning perspective, this paper focuses on developing efficient hybrid 10/100 Gbps LISL planning algorithms. We first propose a uniformly connected 100 Gbps LISL planning algorithm (UC-100GPA) to ensure the widespread deployment of 100 Gbps LISLs across the network. Based on this, a genetic algorithm for 100 Gbps LISL planning optimization (GA-100GPO) is proposed to further determine the sub-optimal deployment ratio of 100 Gbps LISLs in both the intra-orbit plane (intra-OP) and the inter-orbit plane (inter-OP). Simulation results show that UC-100GPA reduces the blocking ratio by 30.32% and 14.88% compared to deployments without 100 Gbps LISLs and with intra-OP 100 Gbps LISLs, respectively. When the traffic load is 800 Erlang, GA-100GPO achieves a blocking ratio of only 0.56% under a sub-optimal deployment ratio of 63.38% intra-OP and 36.62% inter-OP.