Simulating Cellular Communications in Vehicular Networks: Making SimuLTE Interoperable with Veins

The evolution of cellular technologies toward 5G progressively enables efficient and ubiquitous communications in an increasing number of fields. Among these, vehicular networks are being considered as one of the most promising and challenging applications, requiring support for communications in high-speed mobility and delay-constrained information exchange in proximity. In this context, simulation frameworks under the OMNeT++ umbrella are already available: SimuLTE and Veins for cellular and vehicular systems, respectively. In this paper, we describe the modifications that make SimuLTE interoperable with Veins and INET, which leverage the OMNeT++ paradigm, and allow us to achieve our goal without any modification to either of the latter two. We discuss the limitations of the previous solution, namely VeinsLTE, which integrates all three in a single framework, thus preventing independent evolution and upgrades of each building block.Comment: Published in: A. Foerster, A. Udugama, A. Koensgen, A. Virdis, M. Kirsche (Eds.), Proc. of the 4th OMNeT++ Community Summit, University of Bremen - Germany - September 7-8, 201

The Relationship of Skin Conductance to Behavior in a Vigilance Task

The present study is an attempt to measure the correlation between vigilance , as indicated by signal detection, and the galvanic skin response (GSR). The following four dependent variables were measured: (a) Galvanic skin response (continuously recorded, although discrete values were later selected for measurement); (b) ommission errors (where S fails to detect a signal which has occurred); (c) commission errors (or false detections , where S detects a signal which has not in fact occurred); and (d) reaction times to signals. The major purpose of the present study was, in part, to replicate the Ross, Dardano, and Hackman study utilizing more sophisticated equipment and larger number of subjects and, by taking continuous GSR measurements, to more exhaustively test major hypothesis that a relationship exists between the galvanic skin response and vigilance

Nancy: An efficient parallel Network Calculus library

This paper describes Nancy, a Network Calculus (NC) library that allows users to perform complex min-plus and max-plus algebra operations efficiently. To the best of our knowledge, Nancy is the only open-source library that implements operations working on arbitrary piecewise affine functions, as well as to implement some of them (e.g. sub-additive closure and function composition). Nancy allows researchers to compute NC results using a straightforward syntax, which matches the algebraic one. Moreover, it is designed having computational efficiency in mind: it exploits optimizations of data structures, it uses inheritance to allow for faster algorithms when they are available (e.g., for specific subclasses of functions), and it is natively parallel, thus reaping the benefit of multicore hardware. This makes it usable to solve NC problems which were previously considered beyond the realm of tractable

A comprehensive simulation analysis of LTE Discontinuous Reception (DRX)

In an LTE cell, Discontinuous Reception (DRX) allows the central base station to configure User Equipments for periodic wake/sleep cycles, so as to save energy. DRX operations depend on several parameters, which can be tuned to achieve optimal performance with different traffic profiles (i.e., CBR vs. bursty, periodic vs. sporadic, etc.). This work investigates how to configure these parameters and explores the trade-off between power saving, on one side, and per-user QoS, on the other. Unlike previous work, chiefly based on analytical models neglecting key aspects of LTE, our evaluation is carried out via simulation. We use a fully-fledged packet simulator, which includes models of all the protocol stack, the applications and the relevant QoS metrics, and employ factorial analysis to assess the impact of the many simulation factors in a statistically rigorous way. This allows us to analyze a wider spectrum of scenarios, assessing the interplay of the LTE mechanisms and DRX, and to derive configuration guidelines

System-level analysis of the tradeoffs between power saving and capacity/QoS with DRX in LTE

In an LTE cell, Discontinuous Reception (DRX) allows the central base station to configure User Equipment for periodic wake/sleep cycles, so as to save energy. Several parameters are associated to DRX operations, thus allowing for optimal performance with different traffic profiles (i.e., CBR-like, bursty, periodic arrivals of variable-sized packets, etc.). This work investigates how to configure these parameters and explores the tradeoff between power saving, on one side, and per-user QoS and cell capacity, on the other. Unlike previous work, mostly based on analytical models neglecting key aspects of LTE, our evaluation is carried out using a fully-fledged packet simulator. This allows us to discover previously unknown relationships and to propose configuration guidelines for operators

Public sector ICT management strategy and its impact on e-government: a case study

This paper explores the relationship between public sector information and communications technology (ICT) management strategies and electronic government (e-Gov) initiatives. We use an adaptation of the technology enactment framework to explore various technological, organisational, and institutional factors that play a role in the development of ICT management strategies in a public agency. Using the case study of a city (anonymised and referred to in this paper as the ‘City’) in the U.S. state of Connecticut, we examine how these factors in turn help determine the city’s e-Gov initiatives. Our findings show that the bureaucratic structure and culture of the public agency play a key role in the type of ICT strategy adopted in the city and that this has important repercussions for the outcome of its e-Gov programme

Singular Spectrum Analysis: a new decomposition technique applied to environmental systems

EnIn the last few years Singular Spectrum Analysis (SSA), a powerful tool in time series In the last few years Singular Spectrum Analysis (SSA), a powerful tool in time series reconstruction of components may based on the functional clustering algorithm introduced in Bilancia and Stea (2008). We report an example concerning an application in the environmental health field

Exact Worst-case Delay in FIFO-multiplexing Feed-forward Networks

In this paper, we compute the actual worst-case end-to-end delay for a flow in a feed-forward network of first-in–first-out (FIFO)-multiplexing service curve nodes, where flows are shaped by piecewise-affine concave arrival curves, and service curves are piecewise affine and convex. We show that the worst-case delay problem can be formulated as a mixed integer linear programming problem, whose size grows exponentially with the number of nodes involved. Furthermore, we present approximate solution schemes to find upper and lower delay bounds on the worst-case delay. Both only require to solve just one linear programming problem and yield bounds that are generally more accurate than those found in the previous work, which are computed under more restrictive assumptions

Modeling X2 backhauling for LTE-Advanced and assessing its effect on CoMP Coordinated Scheduling

Many LTE-Advanced algorithms and protocols rely on node coordination and cooperation to reduce power consumption, increase spectral efficiency and improve cell-edge performance. Functions such as Coordinated Multi Point, Network Assisted Handover, etc., require a standard connection among nodes to support their operations. The LTE X2 interface meets the above requirements and allows operators to connect nodes for both rel-8 and more advanced (e.g rel-13) functionalities. In this work we describe the modeling of X2 within the SimuLTE system-level simulator. Most research works assume an ideal X2 connection, with null delay and infinite bandwidth. However, the X2 delay and bandwidth do affect the behavior and performance of the aforementioned algorithms. Thus, using CoMP Coordinated Scheduling as a case-study to test X2 functionalities, we show how X2 round-trip delay affects the performance of the CoMP scheduler