Random Access Control and Beam Management Scheme for the 5G NR based Beam Hopping LEO Satellite Communication Systems

This paper considers the scenario that the Low Earth Orbit (LEO) satellite based on Ka-band uses the agile beam to provide Internet access services for users, and studies the random access control and resource scheduling of the agile beam of LEO satellite integrated with 5G. Firstly, the dynamic Access Class Barring (ACB) algorithm is used to reduce the Physical Random Access Channel (PRACH) load and reduce the collisions of preambles. In order to realize the dynamic ACB algorithm, the Auto-regressive Integrated Moving Average (ARIMA) algorithm is used to predict the number of users who want to initiate access. After the random access is completed, the ground 5G New Radio (NR) beam management process is first studied and it is reasonably migrated to the beam management process of the LEO satellite. The beam management algorithms of the signaling beam and the traffic beam are designed, that is, priority scheduling of the maximal predicted requests for the signaling beam and priority scheduling of the maximal remaining traffic for traffic beam. The beam management algorithms ensure that the beam position meets the access time threshold, the service experience time threshold, and the requirement of synchronization, while maximizing the amount of access and provided traffic. Finally, the proposed algorithms are simulated and verified. The results show that the ARIMA algorithm can predict the number of users who want to initiate random access well, and the dynamic ACB algorithm can significantly improve the access success rate and reduce collision probability. Compared with the traditional polling beam management scheme, the proposed algorithms for beam management can improve the service satisfaction rate.