MoN14: Fourteenth Mathematics of Networks meeting

Justin Coon (Oxford) Entropy of random geometric graphs

Random geometric graphs embedded in a bounded region have been extensively investigated in the context of wireless communication network modelling in recent years. Most results have focused on the necessary conditions that must be met for information flow across the network to be possible, i.e., the condition of full connectivity. A less well-understood aspect of these fascinating graphs is their inherent information content, or entropy. The study of this important quantity has applications ranging from connectivity analysis in sparse networks to network topology discovery and routing protocol development. In this lecture, we will explore the entropy of spatially embedded random geometric graphs. We will begin by giving a definition of graph entropy in this context, which naturally links to the properties of the space in which the graph is embedded, and relate this to the entropy of Erd ̈os-R ́enyi graphs. We will then focus on uniform vertex configurations in compact domains and show that for certain pairwise connection functions of interest (dependent upon the inter-vertex distance and relevant physical system parameters) the entropy can be calculated for small typical connection ranges relative to the features of the bounding geometry. Both deterministic and probabilistic pairwise connection functions will be considered. We will then develop a significant new result that gives precise conditions on the typical pairwise connection range that yields a positive, finite entropy as the number of vertices grows large; conversely, this result also gives inter-node connection conditions that yield zero entropy asymptotically. Moving on to arbitrary node configurations, we will study the behaviour of the entropy in the network as the typical connection range grows beyond the diameter of the bounding geometry. Finally, numerous topics for future investigation will be discussed.

Return to previous page

Contact: Keith Briggs (mailto:keith.briggs_at_bt_dot_com) or Richard G. Clegg (