Search results for " Telecom"
showing 10 items of 1269 documents
FLUMO: FLexible Underwater MOdem
2019
The last years have seen a growing interest in underwater acoustic communications because of its applications in marine research, oceanography, marine commercial operations, the offshore oil industry and defense. High-speed communication in the underwater acoustic channel has been challenging because of limited bandwidth, extended multipath, refractive properties of the medium, severe fading, rapid time variation and large Doppler shifts. In this paper, we show an implementation of a flexible Software-Defined Acoustic (SDA) underwater modem, where modulation parameters are completely tunable to optimize performance. In particular, we develop the system architecture following two key ideas. …
A CUDA-based implementation of an improved SPH method on GPU
2021
We present a CUDA-based parallel implementation on GPU architecture of a modified version of the Smoothed Particle Hydrodynamics (SPH) method. This modified formulation exploits a strategy based on the Taylor series expansion, which simultaneously improves the approximation of a function and its derivatives with respect to the standard formulation. The improvement in accuracy comes at the cost of an additional computational effort. The computational demand becomes increasingly crucial as problem size increases but can be addressed by employing fast summations in a parallel computational scheme. The experimental analysis showed that our parallel implementation significantly reduces the runti…
The Risks of WiFi Flexibility: Enabling and Detecting Cheating
2013
Flexibility is an important paradigm for future WiFi networks. However, it also opens the possibility for diverse methods of cheating, which users can perform to increase their throughput. Therefore, it is important to develop the necessary tools to mitigate such efforts. In this paper we first discuss the risks of flexibility in terms of misbehaviour. We then propose an architecture to detect misbehaviour and react by punishing the cheaters. The proposed architecture utilizes advanced passive monitoring, flexible WiFi software, and appropriate reasoning to detect cheating. We validate its performance and discuss means of punishment
Service Provisioning and User Association for Heterogeneous Wireless Railway Networks
2017
In addition to comforting passengers' journey, the modern railway system is responsible to support a variety of on-board Internet services to meet the passenger's demands on seamless service provisioning. In order to provide wireless access to the train, one idea attracting increasing attention is to deploy a series of track-side access points (TAPs) with high-speed data rates along the rail lines dedicated to the broadband mobile service provisioning on board. Due to the heavy data traffic flushing into the base stations (BSs) of the cellular networks, TAPs act as a complement to the BSs in data delivery. In this paper, we focus on the TAP association problem for service provisioning in a …
A game theoretic approach to MAC design for infrastructure networks
2010
Wireless network operation intrinsically assumes different forms of cooperation among the network nodes, such as sharing a common wireless medium without interfering, relaying frames belonging to other nodes, controlling the transmission power for optimizing spectrum reuse, coding cooperatively multiple frames for improving information redundancy, and so on. For this reason, Game Theory has been extensively employed to model wireless networks. In particular, we propose a game-theoretic approach for defining a generalized medium access protocol for slotted contention-based channels. Contention-based channels are largely adopted in data networks, e.g. in WiFi and WiMax networks and in some em…
Joint Sub-Carrier and Power Allocation for Efficient Communication of Cellular UAVs
2020
| openaire: EC/H2020/857031/EU//5G!Drones Cellular networks are expected to be the main communication infrastructure to support the expanding applications of Unmanned Aerial Vehicles (UAVs). As these networks are deployed to serve ground User Equipment (UEs), several issues need to be addressed to enhance cellular UAVs’ services. In this paper, we propose a realistic communication model on the downlink, and we show that the Quality of Service (QoS) for the users is affected by the number of interfering BSs and the impact they cause. The joint problem of sub-carrier and power allocation is therefore addressed. Given its complexity, which is known to be NP-hard, we introduce a solution based …
G-CLASS: geosynchronous radar for water cycle science – orbit selection and system design
2019
The mission geosynchronous – continental land atmosphere sensing system (G-CLASS) is designed to study thediurnal water cycle, using geosynchronous radar. Although the water cycle is vital to human society, processes on timescalesless than a day are very poorly observed from space. G-CLASS, using C-band geosynchronous radar, could transform this. Itsscience objectives address intense storms and high resolution weather prediction, and significant diurnal processes such assnow melt and soil moisture change, with societal impacts including agriculture, water resource management, flooding, andlandslides. Secondary objectives relate to ground motion observations for earthquake, volcano, and subs…
Requirements for Energy Efficient Edge Computing: A Survey
2018
Internet of Things is evolving heavily in these times. One of the major obstacle is energy consumption in the IoT devices (sensor nodes and wireless gateways). The IoT devices are often battery powered wireless devices and thus reducing the energy consumption in these devices is essential to lengthen the lifetime of the device without battery change. It is possible to lengthen battery lifetime by efficient but lightweight sensor data analysis in close proximity of the sensor. Performing part of the sensor data analysis in the end device can reduce the amount of data needed to transmit wirelessly. Transmitting data wirelessly is very energy consuming task. At the same time, the privacy and s…
Latency-Oblivious Distributed Task Scheduling for Mobile Edge Computing
2018
Mobile Edge Computing (MEC) is emerging as one of the effective platforms for offloading the resource- and latency-constrained computational services of modern mobile applications. For latency- and resource-constrained mobile devices, the important issues include: 1) minimize end-to-end service latency; 2) minimize service completion time; 3) high quality-of-service (QoS) requirement to offload the complex computational services. To address the above issues, a latencyoblivious distributed task scheduling scheme is designed in this work to maximize the QoS performance and goodput for the MEC services. Unlike most of the existing works, we consider the latency-oblivious property of different …
Optimization of Linearized Belief Propagation for Distributed Detection
2020
In this paper, we investigate distributed inference schemes, over binary-valued Markov random fields, which are realized by the belief propagation (BP) algorithm. We first show that a decision variable obtained by the BP algorithm in a network of distributed agents can be approximated by a linear fusion of all the local log-likelihood ratios. The proposed approach clarifies how the BP algorithm works, simplifies the statistical analysis of its behavior, and enables us to develop a performance optimization framework for the BP-based distributed inference systems. Next, we propose a blind learning-adaptation scheme to optimize the system performance when there is no information available a pr…