College of Integrated Circuit Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210023, China.
School of Communications and Information Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210023, China.
Sensors (Basel). 2023 Jan 27;23(3):1428. doi: 10.3390/s23031428.
In recent years, low-orbit satellites have become an important development direction in satellite IoT systems. The number of terminals is large and data collisions occur frequently in the low-orbit satellite IoT scenario. How to design a reliable random access protocol to improve the tolerance of the system for collision is one of the research hotspots in this field. In this paper, the random access protocol, used in the Internet of Things (IoT), for low-orbit satellites is studied, and the access process of the IoT terminals in the scenario is constructed. The access performance of the SSA protocol is analyzed and an improved SSA random access strategy, called Retransmission-SSA (R-SSA), is proposed. The simulation results show that the designed R-SSA can effectively tolerate the signal conflicts between terminals in the beam-hopping LEO IoT scenario and improve the probability of the concurrent access of low-orbit sIoT terminals.
近年来，低轨卫星成为卫星物联网系统中的一个重要发展方向。在低轨卫星物联网场景中，终端数量庞大，数据碰撞频繁。如何设计可靠的随机接入协议以提高系统对碰撞的容忍度，是该领域的研究热点之一。本文研究了低轨卫星物联网中的随机接入协议，并构建了物联网终端在该场景下的接入过程。分析了 SSA 协议的接入性能，并提出了一种改进的 SSA 随机接入策略，称为重传 SSA（R-SSA）。仿真结果表明，所设计的 R-SSA 可以有效地容忍波束跳变低轨物联网场景中终端之间的信号冲突，提高低轨 sIoT 终端的并发接入概率。
