Search results for "Communications"
showing 10 items of 3827 documents
Application of Radio Environment Map Reconstruction Techniques to Platoon-based Cellular V2X Communications
2020
Vehicle platoons involve groups of vehicles travelling together at a constant inter-vehicle distance, with different common benefits such as increasing road efficiency and fuel saving. Vehicle platooning requires highly reliable wireless communications to keep the group structure and carry out coordinated maneuvers in a safe manner. Focusing on infrastructure-assisted cellular vehicle to anything (V2X) communications, the amount of control information to be exchanged between each platoon vehicle and the base station is a critical factor affecting the communication latency. This paper exploits the particular structure and characteristics of platooning to decrease the control information exch…
A Two-Dimensional Autoregressive Model for MIMO Wideband Mobile Radio Channels
2008
In this work, we propose the multichannel two- dimensional (2D) autoregressive (AR) model for multiple-input multiple-output (MIMO) wideband mobile wireless channels. The parameters of the proposed model can be estimated from the real- world measurement data. For this purpose, we suggest using a straightforward extension of the prediction error minimization (PEM) algorithm. We also address the problem of possible instability of the multichannel 2D AR model. A model stabilization procedure based on numerical optimization techniques is proposed. The performance of the multichannel 2D AR model has been evaluated based on the synthetic data generated using two different channel simulators.
Level-crossing rate and average duration of fades of non-stationary multipath fading channels
2017
The level-crossing rate (LCR) and average duration of fades (ADF) are important statistical quantities describing the fading behaviour of mobile radio channels. To date, these quantities have only been analysed under the assumption that the mobile radio channel is wide-sense stationary, which is generally not the case in practice. In this paper, we propose a concept for the analysis of the LCR and ADF of non-stationary channels. Rice's standard formula for the derivation of the LCR of wide-sense stationary processes is extended to a more general formula enabling the computation of the instantaneous LCR of non-stationary processes. The application of the new concept results in closed-form ex…
Efficient techniques for energy saving in data center networks
2018
Data centers are constructed with a huge number of network devices to support the expanding cloud based services. These devices are used to achieve the highest performance in case of full utilization of the network. However, the peak capacity of the network is rarely reached. Consequently, many devices are set into idle state and cause a huge energy waste leading to a non-proportionality between the network load and the energy consumed. In this paper, we propose a new approach to improve the efficiency of data centers in terms of energy consumption. Our approach exploits the correlation in time of the inter-node communication traffic and some topological features to maximize energy saving w…
Diffusion of Drone Journalism: the Case of Finland, 2011-2020
2020
This article details Finnish news organizations’ adoption of drones for journalistic purposes from 2011 to 2020. The theoretical starting point of the article is Rogers’ (1962) diffusion of innovations theory, which explains how new ideas and technologies spread in societies. The main empirical data for the study were derived from a phone survey conducted among the 80 most popular newspapers in Finland. The findings reveal that drone journalism in Finland has already diffused from a few pioneering organizations to a large number of newsrooms, including regional, mid-sized newspapers. Most of the newspapers are either using in-house drones, buying commissioned images, or using both strategie…
Resource Allocation for Multi-Access Edge Computing with Fronthaul and Backhaul Constraints
2021
Edge computing is able to provide proximity solutions for the future wireless network to accommodate different types of devices with various computing service demands. Meanwhile, in order to provide ubiquitous connectivities to massive devices over a relatively large area, densely deploying remote radio head (RRH) is considered as a cost-efficient solution. In this work, we consider a vertical and heterogeneous multiaccess edge computing system. In the system, the RRHs are deployed for providing wireless access for the users and the edge node with computing capability can process the computation requests from the users. With the objective to minimize the total energy consumption for process…
Low Latency Ambient Backscatter Communications with Deep Q-Learning for Beyond 5G Applications
2020
Low latency is a critical requirement of beyond 5G services. Previously, the aspect of latency has been extensively analyzed in conventional and modern wireless networks. With the rapidly growing research interest in wireless-powered ambient backscatter communications, it has become ever more important to meet the delay constraints, while maximizing the achievable data rate. Therefore, to address the issue of latency in backscatter networks, this paper provides a deep Q-learning based framework for delay constrained ambient backscatter networks. To do so, a Q-learning model for ambient backscatter scenario has been developed. In addition, an algorithm has been proposed that employ deep neur…
Constrained consistency enforcement in AHP
2020
Abstract Decision-making in the presence of intangible elements must be based on a robust, but subtle, balance between expert know-how and judgment consistency when eliciting that know-how. This balance is frequently achieved as a trade-off reached after a feedback process softens the tension frequently found between one force steadily pulling towards (full) consistency, and another force driven by expert feeling and opinion. The linearization method, developed by the authors in the framework of the analytic hierarchy process, is a pull-towards-consistency mechanism that shows the path from an inconsistent body of judgment elicited from an expert towards consistency, by suggesting optimal c…
Structural and Static Prerequisites for the Internationalization of Small and Medium – Sized Enterprises in the Baltic States
2014
Abstract The pace and extent of internationalization of small and medium-sized enterprises (SMEs) is the result of the interaction of various factors and preconditions. This article examines one of these prerequisites - the currently established structure of SMEs in the Baltic States. The relationship between the different components of SMEs or the SMEs structure is the slowly varying parameters of the functioning of the economy. However, as an integral element of the economic system, the SME structure affects its development, including internationalization of business. Based on statistical data, the opportunities for small firms to outsource business activities as a perspective form of int…
On-surface Synthesis of a Chiral Graphene Nanoribbon with Mixed Edge Structure.
2020
Abstract Chiral graphene nanoribbons represent an important class of graphene nanomaterials with varying combinations of armchair and zigzag edges conferring them unique structure‐dependent electronic properties. Here, we describe the on‐surface synthesis of an unprecedented cove‐edge chiral GNR with a benzo‐fused backbone on a Au(111) surface using 2,6‐dibromo‐1,5‐diphenylnaphthalene as precursor. The initial precursor self‐assembly and the formation of the chiral GNRs upon annealing are revealed, along with a relatively small electronic bandgap of approximately 1.6 eV, by scanning tunnelling microscopy and spectroscopy.