Time-Topology Routing in 3D Networks

Future network infrastructure in beyond 5G/6G era requires new network architecture to increase network coverage in an efficient way rather than extending conventional terrestrial networks. Networks in three-dimensional (3D) space including non-terrestrial networks (NTN) are a promising architecture in beyond 5G/6G, where satellites and flying vehicles behave as network nodes such as routers and base stations to complement terrestrial networks. Hence, in future network infrastructure, not only user equipment (UE) but also routers and base stations move in 3D space, which makes neighbor nodes of each node change at every moment. Additionally, communication quality between each pair of nodes may fluctuate due to environment changes such as weather. Therefore, new routing paradigm, instead of using message exchanges, is necessary to provide stable communication in time-varying 3D networks with node mobility and communication environment change. This paper proposes a time-topology routing method that defines a series of variable-length time frames, its associated temporal topology, and corresponding routing information to provide stable communication in time-varying 3D networks with node mobility and environment changes. Evaluation results show that the proposed method outperforms the existing routing methods based on message exchanges in terms of packet delivery rate with comparable latency, where the proposed method provides stable communication in 3D networks even under severe weather condition.