Showing papers by "Nuno Souto published in 2016"
TL;DR: In this paper, the authors presented an overview of UAVs for civil applications focusing on the communication component and discussed the potential of mobile networks with their fully deployed infrastructures, wide radio coverage, high throughput, reduced latencies, and large availability of radio modems.
Abstract: In this article we presented an overview of UASs for civil applications focusing on the communication component. We identified several available communication technologies for UAVs, their constraints, and also protocols available for implementing the remote operation of the vehicles. As an attractive solution for the A2G communication link for UAVs, we discussed the potential of mobile networks with their fully deployed infrastructures, wide radio coverage, high throughputs, reduced latencies, and large availability of radio modems. We described how a UAS can be implemented in a flexible and modular approach that allows it to rely on one or several wireless (UAVs and GCSs) and wired (GCSs) technologies. Despite the advantages of a system based on cellular and IP networks, there are problems that must be dealt with, namely, possible loss of radio coverage, presence of NAT, delay, jitter, and packet loss. Following the proposed architecture, we implemented an UAS and conducted some flight tests, which showed that the operation of the vehicles in semi-automatic or fully-automatic modes is feasible. It is expected that future enhancements for 4G networks and evolution to 5G will benefit UAV communications even further with lower latencies, higher throughput, and higher reliability.
50 citations
TL;DR: A multiple-input multiple-output detection algorithm based on the alternating direction method of the multipliers (ADMM) is proposed for single-carrier transmissions in time dispersive channels with an overall reduced complexity cost.
Abstract: In this letter, a multiple-input multiple-output detection algorithm based on the alternating direction method of the multipliers (ADMM) is proposed for single-carrier transmissions in time dispersive channels. The ADMM is applied as a heuristic to solve the maximum likelihood detection problem for arbitrary signal constellations formulated in the frequency domain. This approach allows most of the decoding steps to be implemented in the frequency domain with an overall reduced complexity cost. Simulation results show that the performances close to the matched filter bound can be attained in large problem sizes, even in overloaded scenarios.
17 citations
16 May 2016
TL;DR: This work aims to study the environmental and financial feasibility of MNOs becoming carbon neutral, by developing biotic carbon dioxide sequestration programs, and it is shown that achieving carbon neutrality is possible for heterogeneous deployments, especially when low energy powered base stations exist.
Abstract: Increasingly mobile data traffic and high quality service demand has driven fast standards development and new mobile technologies deployment. Traffic demand in 5G networks is expected to rise unprecedentedly, bringing mobile network operators (MNOs) additional challenges, and added pressure regarding carbon footprint reduction. This work aims to study the environmental and financial feasibility of MNOs becoming carbon neutral, by developing biotic carbon dioxide sequestration programs. If feasibility exists, it would be extended and applied to future networks and other environmental scenarios. It is shown that achieving carbon neutrality is possible for heterogeneous deployments, especially when low energy powered base stations like femtocells exist and that the financial costs of such aim might represent little or negligible additional cost expenditure, with the added value of greener and environmental friendly network operation.
7 citations
TL;DR: It is shown that the performance and worst-case computational complexity of the proposed approach makes it very competitive against existing detectors in large problem sizes.
Abstract: In this letter, simple semidefinite relaxations are proposed for the detection of high-order quadrature amplitude modulations in multiple-input–multiple-output systems. The detector is based on the addition of several convex and concave quadratic inequality constraints into the maximum-likelihood detector before relaxing the problem into a convex one. Combined with a randomized sampling procedure, it is shown that the performance and worst-case computational complexity of the proposed approach makes it very competitive against existing detectors in large problem sizes.
6 citations
Journal Article•
TL;DR: An overview of UASs for civil applications focusing on the communication component is presented and it is expected that future enhancements for 4G networks and evolution to 5G will benefit UAV communications even further with lower latencies, higher throughput, and higher reliability.
Abstract: Although the concept was born within military use, in recent years we have witnessed an impressive development of unmanned aerial vehicles (UAVs) for civil and academic applications. Driving this growth is the myriad of possible scenarios where this technology can be deployed, such as: fire detection, search and rescue operations, surveillance, police operations, building and engineering inspections, aerial photography and video for post-disaster assessment, agricultural monitoring, remote detection (radiation, chemical, electromagnetic), weather services, UAV photogrammetry, airborne relay networks, and more [1]. Undoubtedly, the increased use of UAVs has been sustained through the research and development of multiple low-cost solutions for the control of aerial vehicles, the evolution in microelectronics with multiple off-the-shelf components and sensors, and also through a growing global developers community with several UAV related open source projects.
1 citations