Evolution of Non-Terrestrial Networks From 5G to 6G: A Survey

Abstract

Non-terrestrial networks (NTNs) traditionally have certain limited applications. However, the recent technological advancements and manufacturing cost reduction opened up myriad applications of NTNs for 5G and beyond networks, especially when integrated into terrestrial networks (TNs). This article comprehensively surveys the evolution of NTNs highlighting their relevance to 5G networks and essentially, how it will play a pivotal role in the development of 6G ecosystem. We discuss important features of NTNs integration into TNs and the synergies by delving into the new range of services and use cases, various architectures, technological enablers, and higher layer aspects pertinent to NTNs integration. Moreover, we review the corresponding challenges arising from the technical peculiarities and the new approaches being adopted to develop efficient integrated ground-air-space (GAS) networks. Our survey further includes the major progress and outcomes from academic research as well as industrial efforts representing the main industrial trends, field trials, and prototyping towards the 6G networks.

What Will the Future of UAV Cellular Communications Be? A Flight From 5G to 6G

“…The article [34] covers low-and high-altitude-platform-based communication networks, addressing their particular design mechanisms and protocols. More recently, [35] and [36] offer an overview of the architecture and features of an aerial RAN including UAVs and satellites. The articles also discuss 6G application scenarios, propagation-related aspects, energy consumption, communication latency, and network mobility.…”

“…Internet of drones [30]- [32] Space-air-ground networks [33]- [36] Standard-related articles Selected references 3GPP-based studies [37]- [40] 5G-connected UAVs [41], [42] Channel measurements and modeling Selected references…”

Task-Oriented Data Compression for Multi-Agent Communications Over Bit-Budgeted Channels

“…This is inline with what many believe as the mission of the goaloriented/task-oriented communications. Let us recall that the value function here is an indirect measure of usefulness, as it can be obtained for any task that can be expressed via Markov Decision Processes -making it a measure of usefulness that is applicable to a plethora of scenarios [1], [11].…”

“…This bottleneck can occur due to a multitude of reasons (i) the energy lifetime of the communicating agents e.g., in the case of UAV/LEO satellite communications, that forces agents to communicate with low-energy high-range communication protocols [9], [10] (ii) the limitations imposed by the environment on the communication channel e.g., in space/underwater missions or (iii) limited communication resources of the network through which agents communicate. For more on the applications of TODC see [1], [11].…”

Edge Computing and Communication for Energy-Efficient Earth Surveillance with LEO Satellites

“…The last two decades have seen an unprecedented growing trend towards space-based Internet services and the deployment of mega-constellations of LEO satellites by hightech competitors. There is a demanding need to address the standardization of the satellite segment with respect to the ground infrastructure, which will play a pivotal role on the path to 6G [1]. Extending the legacy 5G NTN use cases of no-served and under-served areas, aviation and maritime use cases, the 6G NTN is meant to gather an extensive number of additional use cases including bulk download of Earth Observation data [2].…”