52 research outputs found
Full-Dimension MIMO Arrays with Large Spacings Between Elements
Full-Dimension MIMO is identified as a promising MIMO technique for next cellular standards. It is based on performing beamforming not only in the azimuth but also in the elevation dimension. In this paper, it is studied how the beamforming performance can be enhanced by increasing the spacing between antenna elements. The major claims are that the system capacity can be enhanced by increasing the antenna spacing until the limit in which the grating lobes start falling inside the desired sector. For larger spacings, the benefits of reduced beamwidths are cancelled out by the interference introduced by grating lobes
Polarimetric Control of Reflective Metasurfaces
This letter addresses the synthesis of reflective cells approaching a given
desired Floquet's scattering matrix. This work is motivated by the need to
obtain much finer control of reflective metasurfaces by controlling not only
their co-polarized reflection but also their cross-coupling behavior. The
demonstrated capability will enable more powerful design approaches -involving
all field components in phase and magnitude- and consequently better
performance in applications involving reflective metasurfaces. We first expose
some fundamental theoretical constraints on the cell scattering parameters.
Then, a successful procedure for controlling all four scattering parameters by
applying parallelogram and trapezoid transformations to square patches is
presented, considering both normal and oblique incidence
Low-Cost Hybrid Analog-Digital Beamformer Evaluation in Spectrum Sharing Systems
This paper evaluates different analog-digital beamforming solutions for future spectrum sharing mm-wave scenarios.
In contrast to sub-6 GHz multiantenna schemes where all-digital solutions provide an excellent performance-cost tradeoff,
in the mm-wave bands where a very large number of antennas is required, all-digital designs cannot be deployed due to their cost and complexity. In order to solve this problem, subarray solutions are conceived such that a reduced number of radiofrequency chains are simultaneously connected to different antennas through an analog beamforming network formed by phase shifters (i.e. with no amplitude control). Different connectivity solutions are evaluated; namely, full-connected, localized and interleaved considering that either the phase shifters have full resolution or only one control bit. As reported in the paper, while for the full resolution case the same performance is obtained for all connectivity schemes, in case the phase shifters have one control bit, differences show up. The numerical evaluation is done with an alternating feasible point pursuit successive convex approximation (FPP-SCA) optimization which yields to efficient solutions even for this non-convex optimization problem
Closed-form multicast precoding for satellite flexible payloads
This paper investigates a novel closed-form noniterative precoding technique for multicast multibeam satellite systems. Next-generation satellite systems will be benefited from the flexible use of the satellite resources especially its power flexible allocation among beams. Intending to obtain a low-computational complexity design, we revisit the well-known signal-to-leakage-and-noise ratio design for multicast transmission. Two alternatives are introduced considering both the physical meaning of the ratio and certain multicast channel vector mapping. We observe the benefits of these techniques in satellite flexible payloads. The proposed technique shows a substantial gain compared to the benchmark according to the numerical simulations. Intuitive insights on the precoding behaviour are also presented.This work is funded by Ministry of Science, Innovation and Universities, Spain, under project TERESA -TEC2017-90093-C3-1-R (AEI/FEDER, UE) and by Catalan government under the grant 2017-SGR-01479.Peer ReviewedPostprint (author's final draft
Shared access satellite-terrestrial reconfigurable backhaul network enabled by smart antennas at mm-wave band
© 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.5G traffic expectations require not only the appropriate access infrastructure, but also the corresponding backhaul infrastructure to ensure a well-balanced network scaling. Optical fibre and terrestrial wireless backhaul will hardly meet 100% coverage and satellite must be considered within the 5G infrastructure to boost ubiquitous and reliable network utilization. This work presents the main outcomes of SANSA project, which proposes a novel solution that overcomes the limitations of the traditional fixed backhaul. It is based on a dynamic integrated satelliteterrestrial backhaul network operating on the mm-wave band. Its key principles are a seamless integration of the satellite segment into terrestrial backhaul networks; a terrestrial wireless network capable of reconfiguring its topology according to traffic demands; and an aggressive frequency reuse within the terrestrial segment and between terrestrial and satellite segments. The two technological enablers of SANSA are smart antenna techniques at mm-wave and a software defined intelligent hybrid network management. This article introduces these 5G enablers, which permit satellite communications to play a key role in different 5G use cases, from the early deployment of 5G services in sparse scenarios to enhanced mobile broadband in denser scenarios.Peer ReviewedPostprint (author's final draft
From 5G to 6G: Revolutionizing Satellite Networks through TRANTOR Foundation
5G technology will drastically change the way satellite internet providers
deliver services by offering higher data speeds, massive network capacity,
reduced latency, improved reliability and increased availability. A
standardised 5G ecosystem will enable adapting 5G to satellite needs. The
EU-funded TRANTOR project will seek to develop novel and secure satellite
network management solutions that allow scaling up heterogeneous satellite
traffic demands and capacities in a cost-effective and highly dynamic way.
Researchers also target the development of flexible 6G non-terrestrial access
architectures. The focus will be on the design of a multi-orbit and multi-band
antenna for satellite user equipment (UE), as well as the development of gNodeB
(gNB) and UE 5G non-terrestrial network equipment to support
multi-connectivity
Filter Bank-based Transceiver Design for Ultrawideband
Peer ReviewedPostprint (published version
Shared Access Satellite-Terrestrial Reconfigurable Backhaul Network Enabled by Smart Antennas at MmWave Band
5G traffic expectations require not only the appropriate access infrastructure, but also the corresponding backhaul infrastructure to ensure well-balanced network scaling. Optical fiber and terrestrial wireless backhaul will hardly meet 100 percent coverage, and satellite must be considered within the 5G infrastructure to boost ubiquitous and reliable network utilization. This work presents the main outcomes of the SANSA project, which proposes a novel solution that overcomes the limitations of the traditional fixed backhaul. It is based on a dynamic integrated satellite- terrestrial backhaul network operating on the mmWave band. Its key principles are seamless integration of the satellite segment into terrestrial backhaul networks, a terrestrial wireless network capable of reconfiguring its topology according to traffic demands, and aggressive frequency reuse within the terrestrial segment and between terrestrial and satellite segments. The two technological enablers of SANSA are smart antenna techniques at mmWave and software defined intelligent hybrid network management. This article introduces these 5G enablers, which permit satellite communications to play a key role in different 5G use cases, from the early deployment of 5G services in sparse scenarios to enhanced mobile broadband in denser scenarios
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