The Problem
Network reliability—the probability that a message is propagated properly from a given source to a destination—is a critical topic in computer networks. Efficient message propagation is a cornerstone of modern communication systems, enabling seamless connectivity for various applications such as autonomous driving, global internet access, and real-time data exchange. Two prominent and rapidly evolving domains in this field are Vehicular Ad Hoc Networks (VANETs) and Low-Earth-Orbit (LEO) satellite networks (LSNs).
LSNs, exemplified by constellations such as Starlink, OneWeb, Kuiper, and Lightspeed, promise to provide truly global broadband internet access, reaching regions beyond population centers. This capability has the potential to narrow the digital divide and stimulate economic development in rural and indigenous communities. Operating at much lower altitudes than traditional geosynchronous equatorial orbit (GEO) satellites, LEO satellites offer significantly reduced latency and higher capacity. However, achieving global coverage requires a much larger number of satellites and frequent handovers due to their high velocities. For instance, Starlink currently operates over 6,000 LEO satellites, serving more than four million users across 100+ countries, supported by 9,000+ inter-satellite laser links (ISLs). These satellites deliver throughput up to 100 Mbps with latencies between 20-100ms but necessitate handovers every 15 seconds. Maintaining these laser links and efficiently routing user packets present significant challenges in topology control for LEO satellite networks.
As for our knowledge, no work has been done to explore message propagation in LEO satellites.
Previous Work
Historically, researchers have primarily focused on improving network reliability through protocol enhancements. More recently, efforts have been made to explore the statistical models behind message propagation in VANETs.
The problem of message propagation in VANETs can be broken down into 3 cases: 1d, 2d-ladder, and 2d-lattice. In [1], the authors derived the exact probability expression for both the 1d and 2d-ladder case while the 2d-lattice case was deemed to be not analytically solvable (based on current findings). More recent work was able to improve the results of [1] by proposing a recursive approach for obtaining the directed connectivity expression on arbitrary square lattices. This work is limited and can only be reliable for 10x10 network dimensions. Further research [3] extended the results to 15x15.
Method
The goal of this project is to act as a starting point for my honors project of researching message propagation in LSNs.
The majority of the work will involve literacy review of message propagation in VANETs. By using simulation, the results of these findings will be replicated.
Schedule/Deliverables
First Bi-weekly update (February 21) - Produce a reading summary for [1], research simulation of statistical models and formulate an appropriate plan based on these findings.
Midterm update (March 7) - Produce a git repository and starting code for the simulation, reading summary for [2], JCURA Poster Presentation.
Third Bi-Weekly Update (March 21) - "Rough draft" of final simulation, Reading summary for [3], and start presentation slides and final report.
Final Presentation (April 4)
Final Report (April 18)
References
[1] Y. Zhuang, J. Pan, and L. Cai, “A probabilistic model for message propagation in two-dimensional vehicular ad-hoc networks,” in Proceedings of the seventh ACM international workshop on VehiculAr InterNETworking, New York, NY, USA: ACM, 2010, pp. 31–40. doi: 10.1145/1860058.1860064.
[2] L. Zhang, L. Cai, J. Pan, and F. Tong, A New Approach to the Directed Connectivity in Two-Dimensional Lattice Networks, vol. 13, no. 11. Los Alamitos: IEEE, 2014, pp. 2458–2472. doi: 10.1109/TMC.2014.2314128.
[3] J. Hu, L. Cai, and J. Pan, “Mesh Network Reliability Analysis for Ultra-Reliable Low-Latency Services,” in 2021 IEEE 18th International Conference on Mobile Ad Hoc and Smart Systems (MASS), IEEE, 2021, pp. 198–206. doi: 10.1109/MASS52906.2021.00035