A review on 6G for space-air-ground integrated network: Key enablers, open challenges, and future direction

Abstract

Space-air-ground integrated network (SAGIN) is still in nascent stage of design. Despite of several key insights onto the augmentation of terrestrial, aerial and satellite systems, SAGIN ecosystem is yet not mature enough to survive into the realty. More agility, robustness, flexibility, and scalability are required to conform to optimum standard of abstraction. As 5G is at the verge of technology domain, this is high time when we should keep our focus on the next-generation advanced 6G technology to cater the issues of existing SAGIN ecosystem. In this article, we envisage a clear vision on how 6G can improve the current scenario of the SAGIN infrastructure will some value-added services. We firstly, present basics behind the SAGIN and discuss key concepts of the 6G. Secondly, we review key technologies related to the unmanned aerial vehicle (UAV) and satellite-based communications. Thirdly, we describe key enablers of the 6G-enbled SAGIN i.e., 6G-SAGIN. Fourthly, we present the UAV-as-a-service to augment the comprehension of 6G-SAGIN. Fifthly, we extend the orientation of 6G-SAGIN toward elemental design aspects. Finally, we depict key open research challenges and prescribe some future direction.