以低軌道衛星通訊系統為基礎應用於物聯網之隨機存取程序及頻譜資源配置設計與研究

In the fifth-generation (5G) mobile communications system, massive machinetype communication (mMTC) service scenario is expected to connect billions ofInternet of Things (IoT) devices to the Internet. Because the satellite system hasthe advantages of large signal coverage and low dependence on infrastructureon the ground, the deployment of low-earth orbit (LEO) satellites is a key solutionfor the future wireless communications. With the recent development of LEOsatellite system, satellite communication has been included as the 5G nonterrestrialnetwork (NTN) technique. It is expected to fill up the imperfectdeployment of ground base stations and realize the vision of full coverage. 3GPPhas initiated researches on the new radio (NR) based NTN technology, andarranged corresponding work items in NR Rel-17, which defines three types ofNTN applications: 5G ubiquitous services, satellite access continuous services,and scalable services. Due to the inherent long propagation delay and othercharacteristics of satellite communications, some functions of NR need to beredesigned or modified. There are two main research directions in this project.First, we aim to propose three new RACH Occasion (RO) schemes for the earthfixed cell LEO in order to solve the random access procedure according towhether UE has Global Navigation Satellite System (GNSS) capability. For UEequips with the position information, the potential propagation delay of LEO couldbe pre-compensated. For UE does not have position information, the RACHOccasion (RO) allocation will be designed. Moreover, these proposed ROschemes are also backward compatible with traditional RO schemes. Secondly,in order to solve the inline interference problem that caused by earth moving cellLEO and GEO system share spectrum. Based on the nature frequency hoppingphenomenon, we propose various dynamic radio resource allocation schemes for GEO system. With the coordination between LEO and GEO systems forspectrum allocation, the proposed schemes can reduce inline interference andthereby can not only increase the overall transmission capacity in both systemsbut also achieve fairness.