Link assignment based on vertex deleting using adjacency matrix for LEO optical satellite network

In the LEO optical satellite network (OSN), each satellite has more than a dozen potential links, but the number of onboard terminals is limited. The beam divergence angle of optical satellite communication is extremely small, so only one bidirectional communication link can be established between a pair of communication terminals, therefore how to use limited onboard communication terminals to establish inter-satellite links (ISLs) for each satellite to achieve high-efficiency communication is an urgent problem to be solved. However, previous studies on link assignment schemes cannot take into account the terminal utilization ratio and the small end-to-end delay of the network. To solve the above-mentioned link assignment problem, this paper proposes the link assignment scheme based on vertex deleting using adjacency matrix (VDAM-LAS) for the first time. This scheme can ensure that any number of communication terminals on each satellite can be used to establish ISLs and the smaller network delay and ISLs hops can be obtained. In addition, it solves the link assignment problem of the OSN with the limit of the maximum allowable link hops of a single satellite, which is a problem that cannot be optimized using the previous LASs. The simulation results show that when assigning incessant ISLs, compared with the Manhattan Street Network (MSN)-LAS, greedy-LAS and perfect match model (PMM)-LAS, the average hops are reduced by 8.87%, 3.13%, 0.49%, respectively, and the average propagation delay is reduced by 17.24%, 2.86%, 0.8%, respectively. When assigning intermittent ISLs, the average hops are reduced by 10.45% and 6.89%, respectively, compared with the greedy-LAS and PMM-LAS.