no code implementations • 13 Mar 2024 • Vu Nguyen Ha, Duy H. N. Nguyen, Juan C. -M. Duncan, Jorge L. Gonzalez-Rios, Juan A. Vasquez, Geoffrey Eappen, Luis M. Garces-Socarras, Rakesh Palisetty, Symeon Chatzinotas, Bjorn Ottersten
This paper introduces a joint optimization framework for user-centric beam selection and linear precoding (LP) design in a coordinated multiple-satellite (CoMSat) system, employing a Digital-Fourier-Transform-based (DFT) beamforming (BF) technique.
no code implementations • 18 Jul 2023 • Duc-Dung Tran, Vu Nguyen Ha, Symeon Chatzinotas, Ti Ti Nguyen
In this design, a multi-agent deep Q network (MADQN) approach is employed to conduct the subchannel assignment (SA) among users.
no code implementations • 10 Jul 2023 • Juan Carlos Merlano Duncan, Vu Nguyen Ha, Jevgenij Krivochiza, Rakesh Palisetty, Geoffrey Eappen, Juan Andres Vasquez, Wallace Alves Martins, Symeon Chatzinotas, Björn Ottersten
The space communications industry is challenged to develop a technology that can deliver broadband services to user terminals equipped with miniature antennas, such as handheld devices.
no code implementations • 26 Apr 2023 • Vu Nguyen Ha, Juan Carlos Merlano Duncan, Eva Lagunas, Jorge Querol, Symeon Chatzinotas
This paper proposes a joint optimization framework for energy-efficient linear precoding and feeder-link-beam matching design in a multi-gateway multi-beam bent-pipe satellite communication system.
no code implementations • 19 Mar 2023 • Hung Nguyen-Kha, Vu Nguyen Ha, Eva Lagunas, Symeon Chatzinotas, Joel Grotz
This paper presents a study of an integrated satellite-terrestrial network, where Low-Earth-Orbit (LEO) satellites are used to provide the backhaul link between base stations (BSs) and the core network.
no code implementations • 11 Mar 2023 • Vu Nguyen Ha, Eva Lagunas, Tedros Salih Abdu, Haythem Chaker, Symeon Chatzinotas, Joel Grotz
This paper presents a centralized framework for optimizing the joint design of beam placement, power, and bandwidth allocation in an MEO satellite constellation to fulfill the heterogeneous traffic demands of a large number of global users.
no code implementations • 2 Feb 2023 • Hung Nguyen-Kha, Vu Nguyen Ha, Eva Lagunas, Symeon Chatzinotas, Joel Grotz
This paper aims to develop satellite-user association and resource allocation mechanisms to minimize the total transmit power for integrated terrestrial and non-terrestrial networks wherein a constellation of LEO satellites provides the radio access services to both terrestrial base stations (BSs) and the satellite-enabled users (SUEs).
no code implementations • 16 Nov 2022 • Vu Nguyen Ha, Zaid Abdullah, Geoffrey Eappen, Juan Carlos Merlano Duncan, Rakesh Palisetty, Jorge Luis Gonzalez Rios, Wallace Alves Martins, Hong-Fu Chou, Juan Andres Vasquez, Luis Manuel Garces-Socarras, Haythem Chaker, Symeon Chatzinotas
This paper jointly designs linear precoding (LP) and codebook-based beamforming implemented in a satellite with massive multiple-input multiple-output (mMIMO) antenna technology.
no code implementations • 22 Aug 2022 • Vu Nguyen Ha, Ti Ti Nguyen, Eva Lagunas, Juan Carlos Merlano Duncan, Symeon Chatzinotas
Regarding constraint on the maximum number of illuminated beams per time slot, the technical requirement is formulated as a sparse optimization problem in which the hardware-related beam illumination energy is modeled in a sparsity form of the LP vectors.
no code implementations • 12 Mar 2020 • Hamed Hojatian, Vu Nguyen Ha, Jérémy Nadal, Jean-François Frigon, François Leduc-Primeau
Hybrid beamforming is a promising technology for 5G millimetre-wave communications.