Search results for "communication channel"
showing 10 items of 349 documents
On-body and off-body transmit power control in IEEE 802.15.6 scheduled access networks
2014
Wireless Body Area Networks (WBANs) have received much attention due to the possibility to be used in healthcare applications. For these applications, energy saving is a critical issue, as in many cases, batteries cannot be easily replaced. A transmit power control scheme, able to adapt to the variations of the wireless body channel, will allow consistent energy saving and longer battery life. In this paper we propose a transmit power control scheme suitable for IEEE 802.15.6 narrowband scheduled access networks, in which the transmission power is modulated frame by frame according to a run-time estimation of the channel propagation conditions. A simple and effective line search algorithm i…
On the Statistical Analysis of Equal Gain Combining over Multiple Double Rice Fading Channels in Cooperative Networks
2010
This article analyzes the statistical properties of narrowband mobile-to-mobile (M2M) fading channels with equal gain combining (EGC) under line-of-sight (LOS) propagation conditions. Here, we study a dual-hop amplify-and-forward (AF)relay network. It is assumed that there can exist LOS components in the transmission links between the source mobile station and the destination mobile station via K mobile relays. In order to cater for asymmetric fading conditions in the relay links, the received signal envelope at the output of the equal gain (EG) combiner is thus modeled as a sum of K double Rice processes. These processes are considered to be independent but not necessarily identically dist…
An Electrooculography based Human Machine Interface for wheelchair control
2019
International audience; This paper presents a novel single channel Electrooculography (EOG) based efficient Human–Machine Interface (HMI) for helping the individuals suffering from severe paralysis or motor degenerative diseases to regain mobility. In this study, we propose a robust system that generates control command using only one type of asynchronous eye activity (voluntary eye blink) to navigate the wheelchair without a need of graphical user interface. This work demonstrates a simple but robust and effective multi-level threshold strategy to generate control commands from multiple features associated with the single, double and triple voluntary eye blinks to control predefined action…
Service Regulations, Input Prices and Export Volumes: Evidence from a Panel of Manufacturing Firms
2017
Using a panel of firm‐level data from Spanish manufacturers, this study shows that better service regulation reduces the price of intermediate inputs paid by downstream firms. The beneficial cost effects of services reforms extend to both large and small‐to‐medium sized corporations (SME’s), but the former tend to enjoy greater gains. This feature also manifests itself in international markets. We find evidence of an input cost channel through which service regulations affect the volume of exports of large manufacturers, while the evidence of such a channel is weaker for SME’s. Our estimates indicate that, from 1991 to 2007, large firms increased their volume of exports by an average of 20 …
Predicting lorawan behavior. How machine learning can help
2020
Large scale deployments of Internet of Things (IoT) networks are becoming reality. From a technology perspective, a lot of information related to device parameters, channel states, network and application data are stored in databases and can be used for an extensive analysis to improve the functionality of IoT systems in terms of network performance and user services. LoRaWAN (Long Range Wide Area Network) is one of the emerging IoT technologies, with a simple protocol based on LoRa modulation. In this work, we discuss how machine learning approaches can be used to improve network performance (and if and how they can help). To this aim, we describe a methodology to process LoRaWAN packets a…
Demo - A Cell-level Traffic Generator for LoRa Networks
2017
In this demo we present and validate a LoRa cell traffic generator, able to emulate the behavior of thousands of low-rate sensor nodes deployed in the same cell, by using a single Software Defined Radio (SDR) platform. Differently from traditional generators, whose goal is creating packet flows which emulate specific applications and protocols, our focus is generating a combined radio signal, as seen by a gateway, given by the super-position of the signals transmitted by multiple sensors simultaneously active on the same channel. We argue that such a generator can be of interest for testing different network planning solutions for LoRa networks.
Studying The Hydrological Response Of Urban Catchments Using A Semi-Distributed Linear Non-Linear Model
2000
A conceptual rainfall-runoff model for urban catchment, which incorporates, semi-distributed modelling concepts has been developed. In the proposed model, the catchment is divided in external sub-catchments connected to the drainage network. Each external sub-catchment is modelled as two separate conceptual linear elements, a reservoir and a channel, one for the pervious part, the other for the impervious part of the drainage area. The drainage network is schematised as a cascade of non-linear cells and the flood routing is simplified in the form of kinematic wave and represented as a flux transfer between adjacent cells. Tests carried out using data from the Parco d'Orleans experimental ca…
Modelling urban networks at mega-regional scale: Are increasingly complex urban systems sustainable?
2015
Are the dynamics of mega-regions sustainable or not? We explore the hypothesis that increasing complexity in mega-regions implies less demands on resources needed to generate organized information, thereby making the systems more efficient and stable. This article aims to identify structural indicators for measuring urban networks at the mega-regional scale. We use night-time light data from the broad band near-visible infrared channel of the DMSP-OLS to monitor the dynamics of urbanization. We study the urban networks as graphs, where nodes are cities, and the main road and railway infrastructures represent the edges. We propose four indicators for measuring the complexity, polycentricity,…
Evolution and Learning: Evolving Sensors in a Simple MDP Environment
2003
Natural intelligence and autonomous agents face difficulties when acting in information-dense environments. Assailed by a multitude of stimuli they have to make sense of the inflow of information, filtering and processing what is necessary, but discarding that which is unimportant. This paper aims at investigating the interactions between evolution of the sensorial channel extracting the information from the environment and the simultaneous individual adaptation of agent-control. Our particular goal is to study the influence of learning on the evolution of sensors, with learning duration being the tunable parameter. A genetic algorithm governs the evolution of sensors appropriate for the a…
A Multi-Phase Decode-and-Forward Transmission Protocol in Cognitive Relay Networks: Outage Analysis and Relay Power Allocation
2015
Consider an underlay cognitive relay network with multiple source and destination pairs and that a decode-and-forward scheme is adopted at the relay. We propose a multi-phase transmission protocol in this paper which involves cooperation among source, relay and destination nodes. Given perfect interference elimination before decoding at the destination nodes, we derive closed-form expressions for outage probability calculation over Rayleigh fading channels. Furthermore, the optimal relay power allocation factor which leads to minimal outage probability is determined. Numerical results reveal the conditions under which satisfactory performance can be achieved based on the proposed scheme.