Architectures and Key Technical Challenges for 5G Systems Incorporating Satellites
Architectures and Key Technical Challenges for 5G Systems Incorporating Satellites
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DOI：
10.1109/tvt.2019.2895263
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发表时间：
2019-03-01
影响因子：
6.8
通讯作者：
Cioni, Stefano
中科院分区：
文献类型：
--
作者：
Guidotti, Alessandro;Vanelli-Coralli, Alessandro;Cioni, Stefano
正如最近的商业和标准化努力所反映的那样，卫星通信系统是在没有服务或服务不足的地区扩展和补充地面网络的有希望的解决方案。特别是，3GPP最近启动了一项关于新无线电的研究项目，即5G非地面网络，旨在将卫星系统部署为移动宽带和机器类型通信场景中的独立解决方案或与地面网络集成。然而，典型的卫星信道损伤，如大的路径损耗、延迟和多普勒频移，对基于卫星的NR网络的实现构成了严峻的挑战。在本文中，基于标准化论坛中目前正在讨论的架构选项，我们讨论并评估了卫星信道特性对物理和介质访问控制层的影响，包括增强移动宽带和窄带物联网应用的传输波形和程序。提出的分析表明，主要的技术挑战与PHY/MAC程序有关，特别是随机访问、时序提前和混合自动重复请求，并根据所考虑的服务和体系结构提出了不同的解决方案。
Satellite communication systems are a promising solution to extend and complement terrestrial networks in unserved or under-served areas, as reflected by recent commercial and standardization endeavors. In particular, 3GPP recently initiated a study item for new radio, i.e., 5G, non-terrestrial networks aimed at deploying satellite systems either as a stand-alone solution or as an integration to terrestrial networks in mobile broadband and machine-type communication scenarios. However, typical satellite channel impairments, as large path losses, delays, and Doppler shifts, pose severe challenges to the realization of a satellite-based NR network. In this paper, based on the architecture options currently being discussed in the standardization fora, we discuss and assess the impact of the satellite channel characteristics on the physical and medium access control layers, both in terms of transmitted waveforms and procedures for enhanced mobile broadband and narrowband-Internet of Things applications. The proposed analysis shows that the main technical challenges are related to the PHY/MAC procedures, in particular random access, timing advance, and hybrid automatic repeat request and depending on the considered service and architecture, different solutions are proposed.