Reliable Data Transmission in Challenging Vehicular Network using Delay Tolerant Network

In the 21st century, there has been an increasing tendency toward the wide adoption of wireless networks and technologies due to their significant advantages such as flexibility, mobility, accessibility, and low cost. Wireless technologies have therefore become essential factors in the improvement of intra-vehicle road safety in Vehicular Ad-hoc Network (VANET), which potentially reduce road traffic accidents by enabling efficient exchange of information between vehicles in the early stages. However, due to the inherent high mobility and rapid change of topology, there are numerous challenges in VANET. Hence, different software packages have been combined in this project to create the VANET environment, whereby the Objective Modular Network Testbed (OMNeT++) and the Simulation of Urban Mobility (SUMO), along with Vehicles in Network Simulation (VEINS) are integrated to model the VANET environment. Also, Delay Tolerant Network (DTN) are implemented in the Opportunistic Network Environment (ONE) simulator, where the Store-Carry-Forward technique is used to route traffic. When network resources are not limited, a high delivery ratio is possible. However, when network resources are scarce, these protocols will have a low delivery ratio and high overhead. Due to these limitations, in this research, an extensive performance evaluation of various routing protocols for DTN with different buffer management policies, giving insight into the impact of these policies on DTN routing protocol performance has been conducted. The empirical study gave insight into the strengths and limitations of the existing protocols thus enabling the selection of the benchmark protocols utilized in evaluating a new Enhanced Message Replication Technique (EMRT) proposed in this thesis. The main contribution of this thesis is the design, implementation, and evaluation of a novel EMRT that dynamically adjusts the number of message replicas based on a node's ability to quickly disseminate the message and maximize the delivery ratio. EMRT is evaluated using three different quota protocols: Spray&Wait, Encounter Based Routing (EBR), and Destination Based Routing Protocol (DBRP). Simulation results show that applying EMRT to these protocols improves the delivery ratio while reducing overhead ratio and latency average. For example, when combined with Spray&Wait, EBR, and DBRP, the delivery probability is improved by 13%, 8%, and 10%, respectively, while the latency average is reduced by 51%, 14%, and 13%, respectively

Mobile Ad-Hoc Networks

Being infrastructure-less and without central administration control, wireless ad-hoc networking is playing a more and more important role in extending the coverage of traditional wireless infrastructure (cellular networks, wireless LAN, etc). This book includes state-of-the-art techniques and solutions for wireless ad-hoc networks. It focuses on the following topics in ad-hoc networks: quality-of-service and video communication, routing protocol and cross-layer design. A few interesting problems about security and delay-tolerant networks are also discussed. This book is targeted to provide network engineers and researchers with design guidelines for large scale wireless ad hoc networks

A Heterogeneous Communications Network for Smart Grid by Using the Cost Functions

Smart Grids (SG) is an intelligent power grid in which the different SG node types with different communication requirements communicates different types of information with Control Stations (CS). Radio Access Technologies (RATs) due to its advantages are considered as the main access method to be used in order to have bidirectional data transferring between different node types and CS. Besides, spectrum is a rare source and its demand is increasing significantly. Elaborating a heterogeneous in order to fulfill different SG node types communication requirements effectively, is a challenging issue. To find a method to define desirability value of different RAT to support certain node types based on fitness degree between RAT communication characteristics and node type communication requirements is an appropriate solution. This method is implemented by using a comprehensive Cost Function (CF) including a communication CF (CCF) in combination with Energy CF (ECF). The Key Point Indicators which are used in the CCF are SG node type communication requirements. The existing trade of between Eb/N0 and spectral efficiency is considered as ECF. Based on the achieved CCF and ECF and their tradeoffs, SG node types are assigned to different RATs. The proposed assigning method is sensitive to the SG node types densities. The numerical results are achieved by using MATLAB simulation. The other different outcomes of the research output such as cognitive radio in SG and collectors effect number on data aggregation are discussed as well

Sharing our digital aura through social and physical proximity

Thesis (S.M.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2008.Includes bibliographical references (p. 153-160).People are quite good at establishing a social style and using it in different communications contexts, but they do less well when the communication is mediated by computer networks. It is hard to control what information is revealed and how one's digital persona will be presented or interpreted. In this thesis, we ameliorate this problem by creating a "Virtual Private Milieu", a "VPM", that allows networked devices to act on our behalf and project a "digital aura" to other people and devices around us in a manner analogous to the way humans naturally interact with one another. The dynamic aggregation of the different auras and facets that the devices expose to one another creates social spheres of interaction between sets of active devices, and consequently between people. We focus on the subset of networking that deals with proximate communication, which we dub Face-to-Face Networking (FtFN). Network interaction in this space is often analogous to human face-to-face interaction, and increasingly, our devices are being used in local situations. We describe a VPM framework, key features of which include the incorporation of trust and context parameters into the discovery and communication process, incorporation of multiple contextunique identities, and also the support for multiple degrees of security and privacy. We also present the "Social Dashboard", a readily usable control for one's aura. Finally, we review "Comm.unity", a software package that allows developers and researchers easy implementation and deployment of local and distant social applications, and present two applications developed over this platform.Nadav Aharony.S.M