DVB-S2x Enabled Precoding for High Throughput Satellite Systems

Multi-user Multiple-Input Multiple-Output (MU-MIMO) has allowed recent releases of terrestrial LTE standards to achieve significant improvements in terms of offered system capacity. The publications of the DVB-S2x standard and particularly of its novel superframe structure is a key enabler for applying similar interference management techniques -such as precoding- to multibeam High Throughput Satellite (HTS) systems. This paper presents results resulting from European Space Agency (ESA) funded R&D activities concerning the practical issues that arise when precoding is applied over an aggressive frequency re-use HTS network. In addressing these issues, the paper also proposes pragmatic solutions that have been developed in order to overcome these limitations. Through the application of a comprehensive system simulator, it is demonstrated that important capacity gains (beyond 40%) are to be expected from applying precoding even after introducing a number of significant practical impairments

Advanced space system concepts and their orbital support needs (1980 - 2000). Volume 1: Executive summary

The likely system concepts which might be representative of NASA and DoD space programs in the 1980-2000 time period were studied along with the programs' likely needs for major space transportation vehicles, orbital support vehicles, and technology developments which could be shared by the military and civilian space establishments in that time period. Such needs could then be used by NASA as an input in determining the nature of its long-range development plan. The approach used was to develop a list of possible space system concepts (initiatives) in parallel with a list of needs based on consideration of the likely environments and goals of the future. The two lists thus obtained represented what could be done, regardless of need; and what should be done, regardless of capability, respectively. A set of development program plans for space application concepts was then assembled, matching needs against capabilities, and the requirements of the space concepts for support vehicles, transportation, and technology were extracted. The process was pursued in parallel for likely military and civilian programs, and the common support needs thus identified

Distributed Massive MIMO for LEO Satellite Networks

The ultra-dense deployment of interconnected satellites will characterize future low Earth orbit (LEO) mega-constellations. Exploiting this towards a more efficient satellite network (SatNet), this paper proposes a novel LEO SatNet architecture based on distributed massive multiple-input multiple-output (DM-MIMO) technology allowing ground user terminals to be connected to a cluster of satellites. To this end, we investigate various aspects of DM-MIMO-based satellite network design, the benefits of using this architecture, the associated challenges, and the potential solutions. In addition, we propose a distributed joint power allocation and handover management (D-JPAHM) technique that jointly optimizes the power allocation and handover management processes in a cross-layer manner. This framework aims to maximize the network throughput and minimize the handover rate while considering the quality-of-service (QoS) demands of user terminals and the power capabilities of the satellites. Moreover, we devise an artificial intelligence (AI)-based solution to efficiently implement the proposed D-JPAHM framework in a manner suitable for real-time operation and the dynamic SatNet environment. To the best of our knowledge, this is the first work to introduce and study DM-MIMO technology in LEO SatNets. Extensive simulation results reveal the superiority of the proposed architecture and solutions compared to conventional approaches in the literature.Comment: arXiv admin note: text overlap with arXiv:2106.0983

Analysis and optimization of the satellite-to-plane link of an aeronautical global system

En aquest projecte s'ha analitzat i optimitzat l'enllaç satèl·lit amb avió per a un sistema aeronàutic global. Aquest nou sistema anomenat ANTARES està dissenyat per a comunicar avions amb estacions base mitjançant un satèl·lit. Aquesta és una iniciativa on hi participen institucions oficials en l'aviació com ara l'ECAC i que és desenvolupat en una col·laboració europea d'universitats i empreses. El treball dut a terme en el projecte compren bàsicament tres aspectes. El disseny i anàlisi de la gestió de recursos. La idoneïtat d'utilitzar correcció d'errors en la capa d'enllaç i en cas que sigui necessària dissenyar una opció de codificació preliminar. Finalment, estudiar i analitzar l'efecte de la interferència co-canal en sistemes multifeix. Tots aquests temes són considerats només per al "forward link". L'estructura que segueix el projecte és primer presentar les característiques globals del sistema, després centrar-se i analitzar els temes mencionats per a poder donar resultats i extreure conclusions.En este proyecto se ha analizado y optimizado el enlace satélite a avión para un sistema aeronáutico global. Este nuevo sistema, ANTARES, está diseñado para comunicar aviones y estaciones base mediante un satélite. Esta es una iniciativa europea en la que participan varias instituciones oficiales en aviación como el ECAC y es desarrollada en una colaboración europea de universidades y empresas. El trabajo llevado a cabo en este proyecto comprende básicamente tres aspectos. El diseño y análisis de la gestión de recursos. La idoneidad de usar corrección de errores en la capa de enlace y en caso que sea necesario diseñar una opción de codificación preliminar. Finalmente, estudiar y analizar el efecto de la interferencia co-canal en sistemas multihaz. Todos estos temas se consideran sólo en el "forward link". La estructura que sigue el trabajo es, primero presentar las características globales del sistema, luego centrarse y analizar los temas mencionados para finalmente dar resultados y extraer conclusiones.In this project it is analyzed and optimized the satellite-to-plane link of an aeronautical global system. This new upcoming system called ANTARES is intended for communicating airplanes and ground stations through a satellite system. This is a European initiative involving official institutions in terms of aviation such as the ECAC and developed in a European collaboration of universities and companies. The work carried out in the project comprehends basically three issues. The Radio Resource Management analysis and design. Analyze the suitability of using Link Layer-Forward Error Correction in the system and in case it is necessary design a preliminary coding option. Finally, study and analyze the effect of the co-channel interference in multibeam systems. All these issues are considered only for the forward link of the system. The structure of the project is as follows, first present the global characteristics of the system, then focus and analyze the mentioned subjects and finally give results and take conclusions on the work

Channel Estimation for LEO Satellite Massive MIMO OFDM Communications

In this paper, we investigate the massive multiple-input multiple-output orthogonal frequency division multiplexing channel estimation for low-earth-orbit satellite communication systems. First, we use the angle-delay domain channel to characterize the space-frequency domain channel. Then, we show that the asymptotic minimum mean square error (MMSE) of the channel estimation can be minimized if the array response vectors of the user terminals (UTs) that use the same pilot are orthogonal. Inspired by this, we design an efficient graph-based pilot allocation strategy to enhance the channel estimation performance. In addition, we devise a novel two-stage channel estimation (TSCE) approach, in which the received signals at the satellite are manipulated with per-subcarrier space domain processing followed by per-user frequency domain processing. Moreover, the space domain processing of each UT is shown to be identical for all the subcarriers, and an asymptotically optimal vector for the per-subcarrier space domain linear processing is derived. The frequency domain processing can be efficiently implemented by means of the fast Toeplitz system solver. Simulation results show that the proposed TSCE approach can achieve a near performance to the MMSE estimation with much lower complexity.Comment: accepted by IEEE Transactions on Wireless Communication

Message-splitting for interference cancellation in multibeam satellite systems

This paper investigates a novel technique to deal with the interference in the forward link of multibeam satellite systems when aggressive frequency reuse schemes are employed. Taking into account only magnitude information about the forward channel, the gateway judiciously splits the messages to be transmitted into private and public parts. At the receive terminals, partial cancellation of the public messages is applied prior to private message detection. The practical significance of the absence of channel phase information is stressed and complemented by some additional insights on the implementation. Our numerical results show that, in terms of average total throughput, this technique combined with a 2-colour frequency reuse scheme can outperform a classic orthogonal system with a conservative 4-colour frequency reuse scheme, despite the additional co-channel interference.Grant numbers : SatNEx IV - Satellite Network of Experts IV. © 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works

Joint Use of On-board Reconfigurable Antenna Pattern and Adaptive Coding and Modulation in Satellite Communications at High Frequency Bands

The Telecommunication market is driven by the increasing need of the end users for multimedia services which require high data rates. Within the fixed satellite service, frequency bandwidths wide enough to carry such high data rates are to be found in Ka band (26-40 GHz), and Q/V bands (40-50 GHz). However, at Ka band and above, transmitted signals can be severely affected by tropospheric attenuation for substantial percentages of time, resulting in the degradation of the quality and of the availability of communication services. Fade Mitigation Techniques (FMTs) must be used to counteract these severe propagation impairments. In this thesis we explore the joint use of two of the most promising techniques, known as Reconfigurable Antenna and Adaptive Coding and Modulation, which up to now has been separately developed. Some of our accomplishments include, but are not limited to: a methodology to describe rain attenuation conditions for multiple users in large geographical areas, a tractable framework for the generation of correlated time series of rain attenuation for multiple receiving stations, the comparison of performance between fixed antenna systems and Reconfigurable Antenna system coupled with Adaptive Coding and Modulation

Advances in Satellite Communications Part 2: Guest Editorial

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Cost benefit analysis of space communications technology. Volume 2: Final report

For abstract, see preceding accession