Pre-calculated space-ground integrated structure (P-SGIS) against link cut set (LCS) failures in space-ground...

Fiber link failure is a common and frequent failure type in terrestrial optical networks (TONs). To guarantee the stable operation of the TON against single or multi-link failures, various kinds of survivability technologies have been proposed. Although these survivability technologies are effective in many cases, a link cut set (LCS), which is a set of fiber links whose simultaneous failures can disconnect the TON, presents an extreme situation of network partitioning that these technologies cannot address. Recently, the satellite network has obtained rapid development and various types of satellite constellations are being constructed. Moreover, the laser inter-satellite link (LISL) is studied deeply and verified widely. The satellite optical network (SON) is gradually formed and can be integrated with the TON together into the space-ground integrated optical network (SGION). In the SGION, the LCS failure in the TON can be addressed by the SON. This paper focuses on space-ground integrated protection. A pre-calculated space-ground integrated structure (P-SGIS) is designed. "Pre-calculated" refers to extracting reliable, low-redundant backup protection structures in advance from the physical topology of the SGION, based on prior knowledge, such as satellite movement regularity, failure distribution, and so on. Heuristic algorithms are developed for P-SGIS construction and backup resource reservation. Numerical results show that the P-SGIS-based protection scheme has high resource efficiency and protection success rate.