Content Delivery for High-Speed Railway via Integrated Terrestrial-Satellite Networks

The rapid development of high-speed railway (HSR) system draws great attention and challenges the current broad-band Internet access with high mobility. Though LTE-A networks can provide 100 Mbps throughput within a cell for a train speeding up to 350 km/h, the frequent handovers and service disruptions remain to be handled. This problem is particularly prominent for the delivery of a large volume of contents which demands high throughput and continuous connections. Besides the terrestrial cellular system, a satellite can also provide wireless broadband access with less frequent handovers. Recent advances in low earth orbit (LEO) satellite networks also prove to be practical for content delivery with acceptable delay. Therefore, we present a solution based on the integrated terrestrial-satellite network (ITSN) for high throughput and continuous connectivity. Multipath TCP (MPTCP) protocol is adopted to support multi-bearer communications and we apply network coding to further optimize the performance of MPTCP. Considering the mobility patterns of the HSR and satellite, we propose a scheduling and resource allocation mechanism with the prediction of the handovers and channel situation information (CSI). Cache assisted femto cells are implemented to aggregate the traffic demands and proactively cache the requested contents. Numerical results demonstrate that our solution well resists to the dynamic network conditions and improves the network performance and content delivery efficiency.