Impact analysis of the shortest path movement model on routing strategies for VDTNs in a rural region

Vehicular Delay-Tolerant Network (VDTN) appears as a particular application of the Delay-Tolerant Network (DTN) concept to transit networks. In this paper we analyze the use of a VDTN to provide asynchronous Internet access on a rural remote region scenario. Through simulation we evaluate the impact of a shortest path based movement model on the performance of four DTN routing protocols in respect to message delivery probability and message average delay.Part of this work has been supported by the Instituto de Telecomunicações, Portugal, in the framework of the Project VDTN@Lab, and by the Euro-NF Network of Excellence of Seven Framework Programme of EU

Improving vehicular delay-tolerant network performance with relay nodes

“Copyright © [2009] IEEE. Reprinted from Next Generation Internet Network. NGI '09). ISBN:978-1-4244-4244-7. This material is posted here with permission of the IEEE. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. By choosing to view this document, you agree to all provisions of the copyright laws protecting it.”Vehicular Delay-Tolerant Networking (VDTN) is an extension of the Delay-Tolerant Network (DTN) architecture concept to transit networks. VDTN architecture handles non-real time applications, exploiting vehicles to enable connectivity under unreliable scenarios with unstable links and where an end-to-end path may not exist. Intuitively, the use of stationary store-and-forward devices (relay nodes) located at crossroads where vehicles meet them and should improve the message delivery probability. In this paper, we analyze the influence of the number of relay nodes, in urban scenarios with different numbers of vehicles. It was shown that relay nodes significantly improve the message delivery probability on studied DTN routing protocols.Part of this work has been supported by the Instituto de Telecomunicações, Next Generation Networks and Applications Group, Portugal, in the framework of the Project VDTN@Lab, and by the Euro-NF Network of Excellence of Seven Framework Programme of EU

Throughput Maximization for Mobile Relaying Systems

This paper studies a novel mobile relaying technique, where relays of high mobility are employed to assist the communications from source to destination. By exploiting the predictable channel variations introduced by relay mobility, we study the throughput maximization problem in a mobile relaying system via dynamic rate and power allocations at the source and relay. An optimization problem is formulated for a finite time horizon, subject to an information-causality constraint, which results from the data buffering employed at the relay. It is found that the optimal power allocations across the different time slots follow a "stair-case" water filling (WF) structure, with non-increasing and non-decreasing water levels at the source and relay, respectively. For the special case where the relay moves unidirectionally from source to destination, the optimal power allocations reduce to the conventional WF with constant water levels. Numerical results show that with appropriate trajectory design, mobile relaying is able to achieve tremendous throughput gain over the conventional static relaying.Comment: submitted for possible conference publicatio

Adaptive routing for intermittently connected mobile ad hoe networks

The vast majority of mobile ad hoc networking research makes a very large assumption: that communication can only take place between nodes that are simultaneously accessible within in the same connected cloud (i.e., that communication is synchronous). In reality, this assumption is likely to be a poor one, particularly for sparsely or irregularly populated environments.In this paper we present the Context-Aware Routing (CAR) algorithm. CAR is a novel approach to the provision of asynchronous communication in partially-connected mobile ad hoc networks, based on the intelligent placement of messages. We discuss the details of the algorithm, and then present simulation results demonstrating that it is possible for nodes to exploit context information in making local decisions that lead to good delivery ratios and latencies with small overheads.</p

A Review of Energy Conservation in Wireless Sensor Networks

In wireless sensor networks, energy efficiency plays a major role to determine the lifetime of the network. The network is usually powered by a battery which is hard to recharge. Hence, one major challenge in wireless sensor networks is the issue of how to extend the lifetime of sensors to improve the efficiency. In order to reduce the rate at which the network consumes energy, researchers have come up with energy conservation techniques, schemes and protocols to solve the problem. This paper presents a brief overview of wireless sensor networks, outlines some causes of its energy loss and some energy conservation schemes based on existing techniques used in solving the problem of power management. Keywords: Wireless sensor network, Energy conservation, Duty cycling and Energy efficiency

Making Bundle Protocol Into a Game *

ABSTRACT Over the last ten years interest in the field of delay and disruption-tolerant, challenged, and opportunistic networks has grown dramatically. Communication protocols originally designed to accommodate communication in the intermittent and high-delay environment of deep space have been applied to sensor networks, battlefield networks, and more recently, peer-to-peer content sharing and social networking. However despite a flurry of creative proposals for ways this new technology could be used, and the diaspora of mobile phone apps whose sole novelty is to mimic the behavior of an opportunistic network, the technology has not found its way into common use, even among the researchers who specialize in the field. We are developing competitive challenges, or games, in which participants would use BP in order to accomplish some nominal goal. By making the activity competitive and offering some reward to the best performers, we hope to get large numbers of conference attendees communicating with BP on a daily basis. In the process people will begin to discover how DTN technology and associated applications can be used to meet their own communication needs. Though these games do provide some entertainment value, the point of the activity is to get people using DTNs to communicate in a real environment, to stress test the available DTN software, and to spur the development of DTN-capable applications

Society Dissemination Based Propagation For Data Spreading In Mobiles Social Networks

In mobile ad hoc networks, nodes are dynamically changing their locations. MOBILE ad hoc networks (MANETs) consist of a collection of mobile nodes which can move freely. These nodes can be dynamically self-organized into arbitrary topology networks without a fixed infrastructure. A mobile ad hoc network consists of wireless hosts that may move often. Movement of hosts results in a change in routes, requiring some mechanism for determining new routes. Several routing protocols have already been proposed for ad hoc networks. MSNets can be viewed as a kind of socially aware Delay/ Disruption Tolerant Networks (DTNs). Thanks to the popularization of smart phones (e.g., iPhone, Nokia N95,and Blackberry), MSNets have begun to attract more attention. However, intermittent and uncertain network connectivity make data dissemination in MSNets a challenging problem. Broadcasting is the operation of sending data from a source user to all other users in the network. Most of the envisioned services (ranging from safety applications to traffic management) rely on broadcasting data to the users inside a certain area of interest. For example, location-based services (product prices, tourist points of interest, etc.) can be advertised from salesmen to near-by users. In this paper The objective is to broadcast data from a superuser to other users in the network. There are two main challenges under this paradigm, namely 1) how to represent and characterize user mobility in realistic MSNets; 2) given the knowledge of regular users' movements, how to design an efficient superuser route to broadcast data actively. We first explore several realistic data sets to reveal both geographic and social regularities of human mobility, and further propose the concepts of geocommunity and geocentrality into MSNet analysis