Intelligent Gateway Placement in Satellite-Terrestrial Integrated Network

The satellite-terrestrial integrated network (STIN) can realize genuine ubiquitous communications via integrating the satellite network and the terrestrial network. However, the time-varying links and failed nodes in STIN will cause the network connectivity problem. To ensure reliable network connections and efficient integrated communications, the gateway placement issue in STIN should be studied. In this paper, an intelligent gateway placement scheme is proposed to achieve the higher reliability and lower latency in STIN. Firstly, a network model with satellites and terrestrial nodes is constructed. Then, the network reliability is defined by considering the probability of traffic distribution and network connectivity, and the gateway placement problem is formulated to maximize the network reliability under the constraint of propagation latency, which is obtained by path selection via Dijkstra algorithm. Following that, an intelligent gateway placement (IGP) algorithm with the discrete particle swarm optimization (DPSO) named DPSO-IGP is proposed to solve the gateway placement problem. In DPSO-IGP, the improved K-means method is given to reduce the search scope, and the gateway locations with maximum reliability are determined in virtue of DPSO. Finally, simulation results demonstrate that the proposed DPSO-IGP has superiority in terms of the network reliability and latency compared with the existing gateway placement schemes.