Directed percolation routing for Low-Earth Orbit (LEO) satellite networks and underwater sensor networks

Directed percolation routing for Low-Earth Orbit (LEO) satellite networks and underwater sensor networks:  In a mesh network, the number of ``shortest" paths in terms of hop-count increases exponentially w.r.t. network size. To fully explore path diversity for ultra-reliable and low-latency (URLL) services, we advocate a directed percolation routing  (DPR) strategy, i.e., the message will be forwarded toward the destination hop by hop, so long as the next hop neighbor is closer to the destination.  Using DPR, what is the probability that a packet can reach its destination is the network connectivity problem. Closely related to directed percolation, network connectivity for mesh networks is very complicated to calculate. The existing state-of-the-art can only calculate  connectivity for a lattice network up-to-the size of 10 x 10. In this talk, we introduce a new approach, named Hop-State Algorithm (HSA). HSA is simpler and more scalable to calculate connectivity of lattice network, up-to 16x16 (containing more than $600$-million shortest paths), and can handle general network topology and heterogeneous links.  Based on HSA, we can choose a subset of network links to use to improve network efficiency and by-pass congested links, while ensuring reliability. We apply DPR to ensure URLL services in  low earth orbit (LEO) satellite backbone networks. Using Starlink constellation (with 1,584 satellites) as an example, we show the superior performance using DPR for ensuring high reliability and low latency services. We also apply DPR to underwater sensor networks with harsh communication environment. With appropriate path selection, DPR can ensure transmission reliability and prolong network lifetime.