A Unified Routing Framework for Integrated Space/Air Information Networks

The aerospace-based communications can be managed more efficiently through the construction of an integrated space/air information network by the convergence of satellite (space) and unmanned aerial vehicle (air) networks. Such an integrated network would best fit the advent of delay- and disruption-tolerant networking, in which the data transmission can tolerate long delay and disruption under a store-carry-forward mechanism. Such a network, however, has some challenging research needs due to the network's high mobility of nodes and time-varying topology that may result in high error bit rate and long delay. In this paper, we propose a unified routing framework for this integrated network, where a Hybrid time-space Graph supporting Hierarchical Routing (HGHR) algorithm is achieved. More specifically, the HGHR performs on a hybrid time-space graph, including two subgraphs: a deterministic graph for the space network and a semi-deterministic one for the air network. This latter graph is based on a discrete time homogeneous semi-Markov prediction model. The hybrid time-space graph is then transformed into a state-space graph, based on which, a message forwarding rule under the store-carry-forward mechanism is adopted. Simulation results show that the proposed HGHR algorithm has good performance in terms of message delivery ratio, end-to-end delay, and power consumption.