1,907 research outputs found
Evolution of High Throughput Satellite Systems: Vision, Requirements, and Key Technologies
High throughput satellites (HTS), with their digital payload technology, are
expected to play a key role as enablers of the upcoming 6G networks. HTS are
mainly designed to provide higher data rates and capacities. Fueled by
technological advancements including beamforming, advanced modulation
techniques, reconfigurable phased array technologies, and electronically
steerable antennas, HTS have emerged as a fundamental component for future
network generation. This paper offers a comprehensive state-of-the-art of HTS
systems, with a focus on standardization, patents, channel multiple access
techniques, routing, load balancing, and the role of software-defined
networking (SDN). In addition, we provide a vision for next-satellite systems
that we named as extremely-HTS (EHTS) toward autonomous satellites supported by
the main requirements and key technologies expected for these systems. The EHTS
system will be designed such that it maximizes spectrum reuse and data rates,
and flexibly steers the capacity to satisfy user demand. We introduce a novel
architecture for future regenerative payloads while summarizing the challenges
imposed by this architecture
A review of RFI mitigation techniques in microwave radiometry
Radio frequency interference (RFI) is a well-known problem in microwave radiometry (MWR). Any undesired signal overlapping the MWR protected frequency bands introduces a bias in the measurements, which can corrupt the retrieved geophysical parameters. This paper presents a literature review of RFI detection and mitigation techniques for microwave radiometry from space. The reviewed techniques are divided between real aperture and aperture synthesis. A discussion and assessment of the application of RFI mitigation techniques is presented for each type of radiometer.Peer ReviewedPostprint (published version
Proceedings of the Second International Mobile Satellite Conference (IMSC 1990)
Presented here are the proceedings of the Second International Mobile Satellite Conference (IMSC), held June 17-20, 1990 in Ottawa, Canada. Topics covered include future mobile satellite communications concepts, aeronautical applications, modulation and coding, propagation and experimental systems, mobile terminal equipment, network architecture and control, regulatory and policy considerations, vehicle antennas, and speech compression
Role of satellite communications in 5G ecosystem: perspectives and challenges
The next generation of mobile radio communication systems – so-called 5G – will
provide some major changes to those generations to date. The ability to cope with huge
increases in data traffic at reduced latencies and improved quality of user experience
together with a major reduction in energy usage are big challenges. In addition,
future systems will need to embody connections to billions of objects – the so-called
Internet of Things (IoT) which raises new challenges.Visions of 5G are now available
from regions across the world and research is ongoing towards new standards. The
consensus is a flatter architecture that adds a dense network of small cells operating in
the millimetre wave bands and which are adaptable and software controlled. But what
is the place for satellites in such a vision? The chapter examines several potential
roles for satellites in 5G including coverage extension, IoT, providing resilience,
content caching and multi-cast, and the integrated architecture. Furthermore, the
recent advances in satellite communications together with the challenges associated
with the use of satellite in the integrated satellite-terrestrial architecture are also
discussed
A survey of self organisation in future cellular networks
This article surveys the literature over the period of the last decade on the emerging field of self organisation as applied to wireless cellular communication networks. Self organisation has been extensively studied and applied in adhoc networks, wireless sensor networks and autonomic computer networks; however in the context of wireless cellular networks, this is the first attempt to put in perspective the various efforts in form of a tutorial/survey. We provide a comprehensive survey of the existing literature, projects and standards in self organising cellular networks. Additionally, we also aim to present a clear understanding of this active research area, identifying a clear taxonomy and guidelines for design of self organising mechanisms. We compare strength and weakness of existing solutions and highlight the key research areas for further development. This paper serves as a guide and a starting point for anyone willing to delve into research on self organisation in wireless cellular communication networks
Smart Beamforming for Direct Access to 5G-NR User Equipment from LEO Satellite at Ka-Band
Study how spatial diversity can help in massive IoT and develp signal processing access for MIMO beamformingNon-Terrestrial Networks (NTN), in particular LEO Satellite Networks, are expected to play a key role in extending and complementing terrestrial 5G networks in order to provide services to air, sea and un-served or under-served areas. This work proposes the implementation of a novel scheme called Resource Sharing Beamforming Access (RSBA), which seems a promising solution to deal with scenarios where Bit Error Rate (BER), probability of collision and/or achievable rate are important aspects of study. Given the system architecture presented in this work, RSBA will be proposed as solution in the 5G-NR Sat-IoT scenario. As it is expected, a huge amount of IoT devices will be transmitting in the uplink, and being the case of Non-Orthogonal-Multiple-Access (NOMA), the risk of collisions between devices will increase. The idea, after assessing the channel impairments of a direct link between a LEO Satellite and a NB-IoT device, it to study how spatial diversity via smart beamforming at the receiver will reduce the probability of collision between the devices, and thus increasing the number of users that can access to the media
A Vision and Framework for the High Altitude Platform Station (HAPS) Networks of the Future
A High Altitude Platform Station (HAPS) is a network node that operates in
the stratosphere at an of altitude around 20 km and is instrumental for
providing communication services. Precipitated by technological innovations in
the areas of autonomous avionics, array antennas, solar panel efficiency
levels, and battery energy densities, and fueled by flourishing industry
ecosystems, the HAPS has emerged as an indispensable component of
next-generations of wireless networks. In this article, we provide a vision and
framework for the HAPS networks of the future supported by a comprehensive and
state-of-the-art literature review. We highlight the unrealized potential of
HAPS systems and elaborate on their unique ability to serve metropolitan areas.
The latest advancements and promising technologies in the HAPS energy and
payload systems are discussed. The integration of the emerging Reconfigurable
Smart Surface (RSS) technology in the communications payload of HAPS systems
for providing a cost-effective deployment is proposed. A detailed overview of
the radio resource management in HAPS systems is presented along with
synergistic physical layer techniques, including Faster-Than-Nyquist (FTN)
signaling. Numerous aspects of handoff management in HAPS systems are
described. The notable contributions of Artificial Intelligence (AI) in HAPS,
including machine learning in the design, topology management, handoff, and
resource allocation aspects are emphasized. The extensive overview of the
literature we provide is crucial for substantiating our vision that depicts the
expected deployment opportunities and challenges in the next 10 years
(next-generation networks), as well as in the subsequent 10 years
(next-next-generation networks).Comment: To appear in IEEE Communications Surveys & Tutorial
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