References of "Ortiz Gomez, Flor de Guadalupe 50044130"
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See detailRadio Regulation Compliance of NGSO Constellations’ Interference towards GSO Ground Stations
Jalali, Mahdis UL; Ortiz Gomez, Flor de Guadalupe UL; Lagunas, Eva UL et al

in IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, 12–15 September 2022, Virtual Conference (2022, September)

The commercial low earth orbiting (LEO) satellite constellations have shown unprecedented growth. Accordingly, the risk of generating harmful interference to the geostationary orbit (GSO) satellite ... [more ▼]

The commercial low earth orbiting (LEO) satellite constellations have shown unprecedented growth. Accordingly, the risk of generating harmful interference to the geostationary orbit (GSO) satellite services increases with the number of satel- lites in such mega-constellations. As the GSO arc encompasses the primary and existing satellite assets providing essential fixed and broadcasting satellite services, the interference avoidance for this area is of the utmost importance. In particular, non- geostationary orbit (NGSO) operators should comply with the regulations set up both by their national regulators and by the International Telecommunications Union (ITU) to minimize the impact of emissions on existing GSO and non-GSO systems. In this paper, we first provide an overview of the most recent radio regulations that dictate the NGSO-GSO spectral co-existence. Next, we analyze the NGSO-GSO radio frequency interference for the downlink scenario, following the so-called time-simulation methodology introduced by ITU. The probability distribution of aggregated power flux-density for NGSO co-channel interference is evaluated and assessed, adopting different degrees of exclusion angle strategy for interference avoidance. We conclude the paper by discussing the resulting implications for the continuity of operation and service provision and we provide remarks for future work [less ▲]

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See detailUnsupervised Learning for User Scheduling in Multibeam Precoded GEO Satellite Systems
Ortiz Gomez, Flor de Guadalupe UL; Lagunas, Eva UL; Chatzinotas, Symeon UL

Scientific Conference (2022, June 09)

Future generation SatCom multibeam architectures will extensively exploit full-frequency reuse schemes together with interference management techniques, such as precoding, to dramatically increase ... [more ▼]

Future generation SatCom multibeam architectures will extensively exploit full-frequency reuse schemes together with interference management techniques, such as precoding, to dramatically increase spectral efficiency performance. Precoding is very sensitive to user scheduling, suggesting a joint precoding and user scheduling design to achieve optimal performance. However, the joint design requires solving a highly complex optimization problem which is unreasonable for practical systems. Even for suboptimal disjoint scheduling designs, the complexity is still significant. To achieve a good compromise between performance and complexity, we investigate the applicability of Machine Learning (ML) for the aforementioned problem. We propose three clustering algorithms based on Unsupervised Learning (UL) that facilitate the user scheduling decisions while maximizing the system performance in terms of throughput. Numerical simulations compare the three proposed algorithms (K-means, Hierarchical clustering, and Self-Organization) with the conventional geographic scheduling and identify the main trade-offs. [less ▲]

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See detailMachine Learning for Radio Resource Management in Multibeam GEO Satellite Systems
Ortiz Gomez, Flor de Guadalupe UL; Lei, Lei UL; Lagunas, Eva UL et al

in Electronics (2022), 11(7), 992

Satellite communications (SatComs) systems are facing a massive increase in traffic demand. However, this increase is not uniform across the service area due to the uneven distribution of users and ... [more ▼]

Satellite communications (SatComs) systems are facing a massive increase in traffic demand. However, this increase is not uniform across the service area due to the uneven distribution of users and changes in traffic demand diurnal. This problem is addressed by using flexible payload architectures, which allow payload resources to be flexibly allocated to meet the traffic demand of each beam. While optimization-based radio resource management (RRM) has shown significant performance gains, its intense computational complexity limits its practical implementation in real systems. In this paper, we discuss the architecture, implementation and applications of Machine Learning (ML) for resource management in multibeam GEO satellite systems. We mainly focus on two systems, one with power, bandwidth, and/or beamwidth flexibility, and the second with time flexibility, i.e., beam hopping. We analyze and compare different ML techniques that have been proposed for these architectures, emphasizing the use of Supervised Learning (SL) and Reinforcement Learning (RL). To this end, we define whether training should be conducted online or offline based on the characteristics and requirements of each proposed ML technique and discuss the most appropriate system architecture and the advantages and disadvantages of each approach. [less ▲]

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See detailCooperative Multi-Agent Deep Reinforcement Learning for Resource Management in Full Flexible VHTS Systems
Ortiz Gomez, Flor de Guadalupe UL; Tarchi, Daniele; Martinez, Ramon et al

in IEEE Transactions on Cognitive Communications and Networking (2022), 8(1),

Very high throughput satellite (VHTS) systems are expected to have a huge increase in traffic demand in the near future. Nevertheless, this increase will not be uniform over the entire service area due to ... [more ▼]

Very high throughput satellite (VHTS) systems are expected to have a huge increase in traffic demand in the near future. Nevertheless, this increase will not be uniform over the entire service area due to the non-uniform distribution of users and changes in traffic demand during the day. This problem is addressed by using flexible payload architectures, which allow the allocation of payload resources flexibly to meet the traffic demand of each beam, leading to dynamic resource management (DRM) approaches. However, DRM adds significant complexity to VHTS systems, so in this paper we discuss the use of one reinforcement learning (RL) algorithm and two deep reinforcement learning (DRL) algorithms to manage the resources available in flexible payload architectures for DRM. These algorithms are Q-Learning (QL), Deep Q-Learning (DQL) and Double Deep Q-Learning (DDQL) which are compared based on their performance, complexity and added latency. On the other hand, this work demonstrates the superiority a cooperative multiagent (CMA) decentralized distribution has over a single agent (SA). [less ▲]

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See detailMethod of Rain Attenuation Prediction Based on Long–Short Term Memory Network
Cornejo, Andres; Landeros, Salvador; Matias, Jose Maria et al

in Neural Processing Letters (2022)

Rain attenuation events are one of the foremost drawbacks in satellite communications, impairing satellite link availability. For this reason, it is necessary to foresee rain events to avoid an outage of ... [more ▼]

Rain attenuation events are one of the foremost drawbacks in satellite communications, impairing satellite link availability. For this reason, it is necessary to foresee rain events to avoid an outage of the satellite link. In this paper, we propose and develop a method based on Machine Learning to predict events of rain attenuation without appealing to complex mathematical models. To be specific, we implement a Long–short term memory architecture that is a Deep Learning algorithm based on an artificial recurrent neural network. Furthermore, supervised learning is the learning task for our algorithms. For this purpose, rain attenuation time-series feed the Long–short term memory network at the input to train it. However, the lack of a rainfall database hinders the development of a reliable prediction method. Therefore, we generate a synthetic rain attenuation database by using the recommendations of the International Telecommunication Union. Each model is trained and validated by computational experiments, employing statistical metrics to find the most accurate and reliable models. Thus, the accuracy metric compares the outcomes of the proposal with other related methods and models. As a result, our best model reaches an accuracy of 91.88% versus 87.99% from the external best model, demonstrating superiority over other models/methods. On average, our proposal accuracy reaches a value of 88.08%. Finally, we find out that this proposal can contribute efficiently to improving the performance of satellite system networks by re-routing data traffic or increasing link availabilities, taking advantage of the prediction of rain attenuation events. [less ▲]

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See detailConvolutional Neural Networks for Flexible Payload Management in VHTS Systems
Ortiz Gomez, Flor de Guadalupe UL; Tarchi, Daniele; Martinez, Ramon et al

in IEEE Systems Journal (2021), 15(3), 4675-4686

Very high throughput satellite (VHTS) systems are expected to have a large increase in traffic demand in the near future. However, this increase will not be uniform throughout the service area due to the ... [more ▼]

Very high throughput satellite (VHTS) systems are expected to have a large increase in traffic demand in the near future. However, this increase will not be uniform throughout the service area due to the nonuniform user distribution, and the changing traffic demand during the day. This problem is addressed using flexible payload architectures, enabling the allocation of the payload resources in a flexible manner to meet traffic demand of each beam, leading to dynamic resource management (DRM) approaches. However, DRM adds significant complexity to the VHTS systems, which is why in this article, we are analyzing the use of convolutional neural networks (CNNs) to manage the resources available in flexible payload architectures for DRM. The VHTS system model is first outlined, for introducing the DRM problem statement and the CNN-based solution. A comparison between different payload architectures is performed in terms of DRM response, and the CNN algorithm performance is compared by three other algorithms, previously suggested in the literature to demonstrate the effectiveness of the suggested approach and to examine all the challenges involved. [less ▲]

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See detailOptimization of cost and capacity of broadband satellite system and resources management using Machine Learning techniques
Ortiz Gomez, Flor de Guadalupe UL

Doctoral thesis (2021)

Very High Throughput Satellite (VHTS) systems have an important role to play as a complement to future 5G terrestrial networks to meet the growing traffic demand. In the near future, VHTS systems are ... [more ▼]

Very High Throughput Satellite (VHTS) systems have an important role to play as a complement to future 5G terrestrial networks to meet the growing traffic demand. In the near future, VHTS systems are expected to reach a transmission capacity of 1 Tbps based on frequency reuse/polarization and multibeam coverage schemes. However, the traffic demand in the service area is not uniform and is also changing throughout the day. This means that with a traditional payload, some beams have insufficient resources and others have wasted resources. One solution to this problem is flexible payloads that allow satellite resources to be modified according to traffic demand. According to operators, the main challenges in Satellite Communications (SatComs) is to achieve new generation VHTS systems capable of satisfying traffic demand and to know how to manage resources in an optimal and autonomous way, thus emerging the problem of Dynamic Resource Management (DRM). With this in mind, this thesis studies the optimization for the design of new generation VHTS systems. The study is divided into two parts, satellites with fixed payload and satellites with flexible payload. For the first part, an optimization method is developed that minimizes the cost per Gbps in orbit and maximizes the capacity per beam, as a function of the number of beams, user G/T and annual availability. As an intermediate step between flexibility and a fixed system, the possibility of having a payload that provides coverage with irregularly sized beams depending on traffic demand is studied. While, for flexible systems, new optimization techniques belonging to Machine Learning are studied to manage resources dynamically and autonomously in the system. The results of this thesis provide new contributions for the design of new generations of VHTS broadband satellites and open a possibility for new research lines [less ▲]

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See detailSupervised machine learning for power and bandwidth management in very high throughput satellite systems
Ortiz Gomez, Flor de Guadalupe UL; Tarchi, Daniele; Martinez, Ramon et al

in International Journal of Satellite Communications and Networking (2021)

In the near future, very high throughput satellite (VHTS) systems are expected to have a high increase in traffic demand. However, this increase will not be uniform over the service area and will be also ... [more ▼]

In the near future, very high throughput satellite (VHTS) systems are expected to have a high increase in traffic demand. However, this increase will not be uniform over the service area and will be also dynamic. A solution to this problem is given by flexible payload architectures; however, they require that resource management is performed autonomously and with low latency. In this paper, we propose the use of supervised machine learning, in particular a classification algorithm using a neural network, to manage the resources available in flexible payload architectures. Use cases are presented to demonstrate the effectiveness of the proposed approach, and a discussion is made on all the challenges that are presented. [less ▲]

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See detailOptimization in VHTS Satellite System Design with Irregular Beam Coverage for Non-Uniform Traffic Distribution
Ortiz Gomez, Flor de Guadalupe UL; Salas-Natera, Miguel A.; Martinez, Ramon et al

in Remote Sensing (2021), 13(13),

Very High Throughput Satellites (VHTS) have a pivotal role in complementing terrestrial networks to increase traffic demand. VHTS systems currently assume a uniform distribution of traffic in the service ... [more ▼]

Very High Throughput Satellites (VHTS) have a pivotal role in complementing terrestrial networks to increase traffic demand. VHTS systems currently assume a uniform distribution of traffic in the service area, but in a real system, traffic demands are not uniform and are dynamic. A possible solution is to use flexible payloads, but the cost of the design increases considerably. On the other hand, a fixed payload that uses irregular beam coverage depending on traffic demand allows maintaining the cost of a fixed payload while minimizing the error between offered and required capacity. This paper presents a proposal for optimizing irregular beams coverage and beam pattern, minimizing the costs per Gbps in orbit, the Normalized Coverage Error, and Offered Capacity Error per beam. We present the analysis and performance for the case study and compare it with a previous algorithm for a uniform coverage area. [less ▲]

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See detailLaboratory Tests of ATSC M/H Commercial Receivers Performance on SFN Networks
Matias, Jose Maria; Ortiz Gomez, Flor de Guadalupe UL; Hernandez, Mario et al

in IEEE Latin America Transactions (2020), 18(10),

The Single Frequency Networks (SFN) are widely used in Digital Television transmission networks due to the high spectral efficiency achieved by them. Digital modulation techniques with a cyclic prefix ... [more ▼]

The Single Frequency Networks (SFN) are widely used in Digital Television transmission networks due to the high spectral efficiency achieved by them. Digital modulation techniques with a cyclic prefix, like OFDM (Orthogonal Frequency Division Multiplex) are adequate to define and use SFN networks due to their ability to deal with the artificial multipath produced in a SFN network. Nevertheless, the ATSC 1.0 and ATSC M/H standards use the VSB-8 modulation technique, which has no cyclic prefix, so it is very sensitive to multipath. The ATSC 1.0 standard has been recently implemented in Mexico, so the ATSC M/H standard can be used in the next years because it is compatible with ATSC 1.0, meanwhile ATSC 3.0, the newest standard of ATSC, it is not compatible.The performance of the reception with VSB-8 modulation depends strongly on the receiver channel equalizer. For this reason, the objective of this study is to analyze the performance of ATSC M/H commercial receivers in SFN networks. The results of this study will help in the implementation of SFN networks in Mexico and other countries that use ATSC 1.0 and ATSC M/H. [less ▲]

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See detailForward Link Optimization for the Design of VHTS Satellite Networks
Ortiz Gomez, Flor de Guadalupe UL; Martinez, Ramon; Salas-Natera, Miguel A. et al

in Electronics (2020), 9(3),

The concept of geostationary VHTS (Very High Throughput Satellites) is based on multibeam coverage with intensive frequency and polarization reuse, in addition to the use of larger bandwidths in the ... [more ▼]

The concept of geostationary VHTS (Very High Throughput Satellites) is based on multibeam coverage with intensive frequency and polarization reuse, in addition to the use of larger bandwidths in the feeder links, in order to provide high capacity satellite links at a reduced cost per Gbps in orbit. The dimensioning and design of satellite networks based on VHTS imposes the analysis of multiple trade-offs to achieve an optimal solution in terms of cost, capacity, and the figure of merit of the user terminal. In this paper, we propose a new method for sizing VHTS satellite networks based on an analytical expression of the forward link CINR (Carrier-to-Interference-plus-Noise Ratio) that is used to evaluate the trade-off of different combinations of system parameters. The proposed method considers both technical and commercial requirements as inputs, including the constraints to achieve the optimum solution in terms of the user G/T, the number of beams, and the system cost. The cost model includes both satellite and ground segments. Exemplary results are presented with feeder links using Q/V bands, DVB-S2X and transmission methods based on CCM and VCM (Constant and Variable Coding and Modulation, respectively) in two scenarios with different service areas. [less ▲]

Detailed reference viewed: 24 (2 UL)