Delay-Optimal Cooperation Transmission in Remote Sensing Satellite Networks
Long Chen, Feilong Tang, Xu Li, Jiacheng Liu, Yanqin Yang, Jiadi Yu, Yanmin Zhu
Abstract
Many remote sensing applications, such as forest fire monitoring, need to send a large volume of data to the ground with low delay. Therefore, the cooperation transmission, which relies on cooperation among satellites to achieve continuous transmission, emerges as an indispensable technique. Most existing work cannot minimize the delay through dynamic cooperation transmission. In this paper, we investigate how to minimize the delay in remote sensing satellite networks based on cooperation transmission, where cooperation hotspots refer to the satellites with ground-satellite links to the Earth Stations (ESs). First, we propose the cooperation capability model to quantify capabilities of cooperation hotspots. Then, we formulate the satellite cooperation transmission problem and prove its NP-hardness. To solve the problem, we propose the delay-minimized cooperation transmission scheme. Both CCT and DCT algorithms adapt well to the dynamic topology and time-varying available resources. Finally, we formally analyze the approximation ratios and the time complexities of both algorithms. We also prove that the DCT always setups loop-free paths. NS2-based simulation results demonstrate that our schemes have good scalability, and both CCT and DCT algorithms reduce the end-to-end delay on average by more than 21.77%, and significantly improve throughput, packet loss rate and flow completion time.