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Alberto Ginesi

Bio: Alberto Ginesi is an academic researcher from European Space Agency. The author has contributed to research in topics: Communications satellite & High-throughput satellite. The author has an hindex of 12, co-authored 45 publications receiving 920 citations. Previous affiliations of Alberto Ginesi include European Space Research and Technology Centre.

Papers
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Journal ArticleDOI
TL;DR: The proposed algorithms are shown to provide a good trade‐off between complexity and performance and they apply to both the broadcast and the unicast profiles, the latter allowing the exploitation of adaptive coding and modulation (ACM).
Abstract: SUMMARY In this paper we propose a design of the main modulation and demodulation units of a modem compliant with the new DVB-S2 standard (Int. J. Satellite Commun. 2004; 22:249–268). A typical satellite channel model consistent with the targeted applications of the aforementioned standard is assumed. In particular, non-linear pre-compensation as well as synchronization techniques are described in detail and their performance assessed by means of analysis and computer simulations. The proposed algorithms are shown to provide a good trade-off between complexity and performance and they apply to both the broadcast and the unicast profiles, the latter allowing the exploitation of adaptive coding and modulation (ACM) (Proceedings of the 20th AIAA Satellite Communication Systems Conference, Montreal, AIAA-paper 2002-1863, May 2002). Finally, end-to-end system performances in term of BER versus the signal-to-noise ratio are shown as a result of extensive computer simulations. The whole communication chain is modelled in these simulations, including the BCH and LDPC coder, the modulator with the pre-distortion techniques, the satellite transponder model with its typical impairments, the downlink chain inclusive of the RF-front-end phase noise, the demodulator with the synchronization sub-system units and finally the LDPC and BCH decoders. Copyright # 2004 John Wiley & Sons, Ltd.

262 citations

Journal ArticleDOI
TL;DR: The vision on advanced precoding techniques and user clustering methods for multibeam broadband fixed satellite communications and practical challenges to deploy precoding schemes and the support introduced in the recently published DVB-S2X standard are provided.
Abstract: Whenever multibeam satellite systems target very aggressive frequency reuse in their coverage area, inter-beam interference becomes the major obstacle for increasing the overall system throughput. As a matter of fact, users located at the beam edges suffer from very large interference for even a moderately aggressive planning of reuse-2. Although solutions for inter-beam interference management have been investigated at the satellite terminal, it turns out that the performance improvement does not justify the increased terminal complexity and cost. In this article, we pay attention to interference mitigation techniques that take place at the transmitter (i.e., the gateway). Based on this understanding, we provide our vision on advanced precoding techniques and user clustering methods for multibeam broadband fixed satellite communications. We also discuss practical challenges to deploy precoding schemes and the support introduced in the recently published DVB-S2X standard. Future challenges for novel configurations employing precoding are also provided.

180 citations

Journal ArticleDOI
TL;DR: It is demonstrated that important capacity gains are to be expected from applying precoding even after introducing a number of significant practical impairments, and proposed pragmatic solutions that have been developed in order to overcome these limitations.
Abstract: Multi-user multiple-input multiple-output MU-MIMO has allowed recent releases of terrestrial long-term evolution LTE standards to achieve significant improvements in terms of offered system capacity. The publication 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 from the European Space Agency-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. Copyright © 2015 John Wiley & Sons, Ltd.

82 citations

Journal ArticleDOI
TL;DR: This article presents the novel FPGA-based 1 Gb/s near-Shannon-limit ACM modem developed within the MHOMS program with particular focus on the advanced modem algorithm solutions devised.
Abstract: This article presents the novel FPGA-based 1 Gb/s near-Shannon-limit ACM modem developed within the MHOMS program with particular focus on the advanced modem algorithm solutions devised. A number of powerful FEC schemes have been analyzed as possible candidates for the MHOMS modem, and the final selection is justified in terms of the best tradeoff between complexity and performance. State-of-the-art modulation and demodulation algorithms are also presented, including nonlinearity dynamic precompensation techniques and innovative synchronization strategies required by the selected powerful modulation and coding schemes. Overall modem performances are also shown for a variety of spectral efficiencies.

80 citations

Journal ArticleDOI
TL;DR: An extension of AIS to a long‐range positioning reporting through a constellation of LEO satellites is presented and technical challenges like the high rate of message collisions from ships in the field of view of a satellite are outlined.
Abstract: The Automatic Identification System (AIS) is a VHF communication system that provides identification/location information to vessels and shore stations by exchanging data such as position, identification, course, speed, etc. Recently, the interest in detecting and tracking ships at distances from coastlines larger than what can be accomplished by normal terrestrial VHF communications has grown, driven by requirements of long-range applications such as better handling of hazardous cargo, improved security and countering illegal operations. This paper presents an extension of AIS to a long-range positioning reporting through a constellation of LEO satellites. It outlines technical challenges like the high rate of message collisions from ships in the field of view of a satellite. Technical solutions are proposed at system and sub-system level to address these challenges. A computer-based system simulator is used to assess the system performance and carry out a high-level system sizing. Results show that a relatively small constellation of LEO satellites can guarantee good ship position detection probability as well as a reporting time interval of a few hours. System performance aspects to be addressed in future work are the possible impact of terrestrial mobile communications interference as well as variations of the estimated traffic data. Copyright © 2009 John Wiley & Sons, Ltd.

77 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, the authors present a survey of the state of the art in satellite communications, while highlighting the most promising open research topics, such as new constellation types, on-board processing capabilities, non-terrestrial networks and space-based data collection/processing.
Abstract: Satellite communications (SatComs) have recently entered a period of renewed interest motivated by technological advances and nurtured through private investment and ventures. The present survey aims at capturing the state of the art in SatComs, while highlighting the most promising open research topics. Firstly, the main innovation drivers are motivated, such as new constellation types, on-board processing capabilities, non-terrestrial networks and space-based data collection/processing. Secondly, the most promising applications are described, i.e., 5G integration, space communications, Earth observation, aeronautical and maritime tracking and communication. Subsequently, an in-depth literature review is provided across five axes: i) system aspects, ii) air interface, iii) medium access, iv) networking, v) testbeds & prototyping. Finally, a number of future challenges and the respective open research topics are described.

475 citations

Journal ArticleDOI
03 Jan 2006
TL;DR: The paper provides a tutorial overview of the DVB-S2 system, describing its main features and performance in various scenarios and applications.
Abstract: DVB-S2 is the second-generation specification for satellite broad-band applications, developed by the Digital Video Broadcasting (DVB) Project in 2003. The system is structured as a toolkit to allow the implementation of the following satellite applications: TV and sound broadcasting, interactivity (i.e., Internet access), and professional services, such as TV contribution links and digital satellite news gathering. It has been specified around three concepts: best transmission performance approaching the Shannon limit, total flexibility, and reasonable receiver complexity. Channel coding and modulation are based on more recent developments by the scientific community: low density parity check codes are adopted, combined with QPSK, 8PSK, 16APSK, and 32APSK modulations for the system to work properly on the nonlinear satellite channel. The framing structure allows for maximum flexibility in a versatile system and also synchronization in worst case configurations (low signal-to-noise ratios). Adaptive coding and modulation, when used in one-to-one links, then allows optimization of the transmission parameters for each individual user,dependant on path conditions. Backward-compatible modes are also available,allowing existing DVB-S integrated receivers-decoders to continue working during the transitional period. The paper provides a tutorial overview of the DVB-S2 system, describing its main features and performance in various scenarios and applications.

383 citations

Journal ArticleDOI
TL;DR: A novel user pairing scheme is developed so that more than two users can be grouped in a cluster to exploit the NOMA technique and an iterative penalty function-based beamforming scheme is presented to obtain the BF weight vectors and power coefficients with fast convergence.
Abstract: In this paper, we propose a joint optimization design for a non-orthogonal multiple access (NOMA)-based satellite-terrestrial integrated network (STIN), where a satellite multicast communication network shares the millimeter wave spectrum with a cellular network employing NOMA technology. By assuming that the satellite uses multibeam antenna array and the base station employs uniform planar array, we first formulate a constrained optimization problem to maximize the sum rate of the STIN while satisfying the constraint of per-antenna transmit power and quality-of-service requirements of both satellite and cellular users. Since the formulated optimization problem is NP-hard and mathematically intractable, we develop a novel user pairing scheme so that more than two users can be grouped in a cluster to exploit the NOMA technique. Based on the user clustering, we further propose to transform the non-convex problem into an equivalent convex one, and present an iterative penalty function-based beamforming (BF) scheme to obtain the BF weight vectors and power coefficients with fast convergence. Simulation results confirm the effectiveness and superiority of the proposed approach in comparison with the existing works.

273 citations

Journal ArticleDOI
TL;DR: An overview of the current 5G initiatives and projects followed by a proposed architecture for 5G satellite networks where the SDN/NFV approach facilitates the integration with the 5G terrestrial system is provided.
Abstract: Future 5G mobile communication systems are expected to integrate different radio access technologies, including the satellite component. Within the 5G framework, the terrestrial services can be augmented with the development of HTS systems and new mega-constellations meeting 5G requirements, such as high bandwidth, low latency, and increased coverage including rural areas, air, and seas. This article provides an overview of the current 5G initiatives and projects followed by a proposed architecture for 5G satellite networks where the SDN/NFV approach facilitates the integration with the 5G terrestrial system. In addition, a novel technique based on network coding is analyzed for the joint exploitation of multiple paths in such an integrated satellite-terrestrial system. For TCP-based applications, an analytical model is presented to achieve an optimal traffic split between terrestrial and satellite paths and optimal redundancy levels.

236 citations

Journal ArticleDOI
01 Jul 2016-PLOS ONE
TL;DR: This study presents the first comprehensive approach to detect and identify potential fishing behavior for three major gear types operating on a global scale, and hopes that this work will enable new efforts to assess the spatial and temporal distribution of global fishing effort and make global fisheries activities transparent to ocean scientists, managers and the public.
Abstract: A key challenge in contemporary ecology and conservation is the accurate tracking of the spatial distribution of various human impacts, such as fishing. While coastal fisheries in national waters are closely monitored in some countries, existing maps of fishing effort elsewhere are fraught with uncertainty, especially in remote areas and the High Seas. Better understanding of the behavior of the global fishing fleets is required in order to prioritize and enforce fisheries management and conservation measures worldwide. Satellite-based Automatic Information Systems (S-AIS) are now commonly installed on most ocean-going vessels and have been proposed as a novel tool to explore the movements of fishing fleets in near real time. Here we present approaches to identify fishing activity from S-AIS data for three dominant fishing gear types: trawl, longline and purse seine. Using a large dataset containing worldwide fishing vessel tracks from 2011-2015, we developed three methods to detect and map fishing activities: for trawlers we produced a Hidden Markov Model (HMM) using vessel speed as observation variable. For longliners we have designed a Data Mining (DM) approach using an algorithm inspired from studies on animal movement. For purse seiners a multi-layered filtering strategy based on vessel speed and operation time was implemented. Validation against expert-labeled datasets showed average detection accuracies of 83% for trawler and longliner, and 97% for purse seiner. Our study represents the first comprehensive approach to detect and identify potential fishing behavior for three major gear types operating on a global scale. We hope that this work will enable new efforts to assess the spatial and temporal distribution of global fishing effort and make global fisheries activities transparent to ocean scientists, managers and the public.

173 citations