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Near-Space Communications: the Last Piece of 6G Space-Air-Ground-Sea Integrated Network Puzzle

Hongshan Liu, Tong Qin, Zhen Gao, Tianqi Mao, Keke Ying, Ziwei Wan, Li Qiao, Rui Na, Zhongxiang Li, Chun Hu, Yikun Mei, Tuan Li, Guanghui Wen, Lei Chen, Zhonghuai Wu, Ruiqi Liu, Gaojie Chen, Shuo Wang, Dezhi Zheng

TL;DR

It is highlighted that the NS-COM plays an indispensable role in the SAGSIN puzzle, providing substantial performance and coverage enhancement to the traditional SAGSIN architecture.

Abstract

This article presents a comprehensive study on the emerging near-space communications (NS-COM) within the context of space-air-ground-sea integrated network (SAGSIN). Specifically, we firstly explore the recent technical developments of NS-COM, followed by the discussions about motivations behind integrating NS-COM into SAGSIN. To further demonstrate the necessity of NS-COM, a comparative analysis between the NS-COM network and other counterparts in SAGSIN is conducted, covering aspects of deployment, coverage, channel characteristics and unique problems of NS-COM network. Afterwards, the technical aspects of NS-COM, including channel modeling, random access, channel estimation, array-based beam management and joint network optimization, are examined in detail. Furthermore, we explore the potential applications of NS-COM, such as structural expansion in SAGSIN communication, civil aviation communication, remote and urgent communication, weather monitoring and carbon neutrality. Finally, some promising research avenues are identified, including stratospheric satellite (StratoSat) -to-ground direct links for mobile terminals, reconfigurable multiple-input multiple-output (MIMO) and holographic MIMO, federated learning in NS-COM networks, maritime communication, electromagnetic spectrum sensing and adversarial game, integrated sensing and communications, StratoSat-based radar detection and imaging, NS-COM assisted enhanced global navigation system, NS-COM assisted intelligent unmanned system and free space optical (FSO) communication. Overall, this paper highlights that the NS-COM plays an indispensable role in the SAGSIN puzzle, providing substantial performance and coverage enhancement to the traditional SAGSIN architecture.

Near-Space Communications: the Last Piece of 6G Space-Air-Ground-Sea Integrated Network Puzzle

TL;DR

It is highlighted that the NS-COM plays an indispensable role in the SAGSIN puzzle, providing substantial performance and coverage enhancement to the traditional SAGSIN architecture.

Abstract

This article presents a comprehensive study on the emerging near-space communications (NS-COM) within the context of space-air-ground-sea integrated network (SAGSIN). Specifically, we firstly explore the recent technical developments of NS-COM, followed by the discussions about motivations behind integrating NS-COM into SAGSIN. To further demonstrate the necessity of NS-COM, a comparative analysis between the NS-COM network and other counterparts in SAGSIN is conducted, covering aspects of deployment, coverage, channel characteristics and unique problems of NS-COM network. Afterwards, the technical aspects of NS-COM, including channel modeling, random access, channel estimation, array-based beam management and joint network optimization, are examined in detail. Furthermore, we explore the potential applications of NS-COM, such as structural expansion in SAGSIN communication, civil aviation communication, remote and urgent communication, weather monitoring and carbon neutrality. Finally, some promising research avenues are identified, including stratospheric satellite (StratoSat) -to-ground direct links for mobile terminals, reconfigurable multiple-input multiple-output (MIMO) and holographic MIMO, federated learning in NS-COM networks, maritime communication, electromagnetic spectrum sensing and adversarial game, integrated sensing and communications, StratoSat-based radar detection and imaging, NS-COM assisted enhanced global navigation system, NS-COM assisted intelligent unmanned system and free space optical (FSO) communication. Overall, this paper highlights that the NS-COM plays an indispensable role in the SAGSIN puzzle, providing substantial performance and coverage enhancement to the traditional SAGSIN architecture.
Paper Structure (34 sections, 8 figures, 2 tables)

This paper contains 34 sections, 8 figures, 2 tables.

Table of Contents

  1. Introduction
  2. The Development of SAGSIN
  3. Motivations of Introducing Near-Space Communication Network
  4. Characteristics of NS-COM Network
  5. Deployment
  6. Coverage
  7. Temporal Coverage
  8. Spatial Coverage
  9. Channel Characteristics
  10. Unique Problems of NS-COM Network
  11. Key Technologies of NS-COM network
  12. Channel Modeling
  13. Random Access
  14. Channel Estimation
  15. Array-Based Beam Management
  16. ...and 19 more sections

Figures (8)

  • Figure 1: Schematic diagram of the SAGSIN architecture, consisting of spaceborne, near-space, airborne and terrestrial networks.
  • Figure 2: The outline of this paper.
  • Figure 3: The layers of Earth's atmosphere, where the near-space region is specified, with a white line showing the atmospheric temperature and a red line showing the pressure at various heights enggXiao.
  • Figure 4: A schematic diagram of different roles StratoSats play in the network architectures.
  • Figure 5: RMSE comparison of angle estimation: (a) azimuth angle; and (b) elevation angle in 9398858.
  • ...and 3 more figures