10,100 research outputs found
VECTORS: Video communication through opportunistic relays and scalable video coding
Crowd-sourced video distribution is frequently of interest in the local
vicinity. In this paper, we propose a novel design to transfer such content
over opportunistic networks with adaptive quality encoding to achieve
reasonable delay bounds. The video segments are transmitted between source and
destination in a delay tolerant manner using the Nearby Connections Android
library. This implementation can be applied to multiple domains, including farm
monitoring, wildlife, and environmental tracking, disaster response scenarios,
etc. In this work, we present the design of an opportunistic contact based
system, and we discuss basic results for the trial runs within our institute.Comment: 13 pages, 6 figures, and under 3000 words for submission to the
SoftwareX journa
Opportunistic Key Management in Delay Tolerant Networks
Key Management is considered to be a challenging task in Delay Tolerant Networks (DTNs) operating in environments with adverse communication conditions such as space, due to the practical limitations and constraints prohibiting effective closed loop communications. In this paper we propose opportunistic key management as a more suitable solution for key management in networks requiring opportunistic behaviour. We show that opportunistic key management is better exploited and utilized when used in conjunction with routing decisions by security aware DTN nodes
HRSON: Home-based Routing for Smartphones in Opportunistic Networks
Opportunistic networks are delay-tolerant networks which enable network
connectivity while there is limited access to network infrastructure, such as
natural disaster happenings. Since opportunistic networks use
store-carry-forward mechanism to deliver data, routing algorithms have
significant impact on successful data delivery. Due to the Operating System
restrictions, creating an opportunistic network using ad-hoc model is not
feasible on smartphones and to the best of our knowledge, none of common
zero-knowledge routing algorithms have been proposed for a non-ad hoc
communication model. In this paper, we propose HRSON, a zero-knowledge routing
algorithm in a self-organizing approach that an opportunistic
infrastructure-based WiFi network is built to use smartphones. We have deployed
our approach in simulated scenario of working days of people, whom are using
smartphones, on Helsinki map comparing to common zero-knowledge routing
algorithms. The results show that our solution increases the average
delivery-rate and lowers delay and commutation overhead
In Vivo Evaluation of the Secure Opportunistic Schemes Middleware using a Delay Tolerant Social Network
Over the past decade, online social networks (OSNs) such as Twitter and
Facebook have thrived and experienced rapid growth to over 1 billion users. A
major evolution would be to leverage the characteristics of OSNs to evaluate
the effectiveness of the many routing schemes developed by the research
community in real-world scenarios. In this paper, we showcase the Secure
Opportunistic Schemes (SOS) middleware which allows different routing schemes
to be easily implemented relieving the burden of security and connection
establishment. The feasibility of creating a delay tolerant social network is
demonstrated by using SOS to power AlleyOop Social, a secure delay tolerant
networking research platform that serves as a real-life mobile social
networking application for iOS devices. SOS and AlleyOop Social allow users to
interact, publish messages, and discover others that share common interests in
an intermittent network using Bluetooth, peer-to-peer WiFi, and infrastructure
WiFi.Comment: 6 pages, 4 figures, accepted in ICDCS 2017. arXiv admin note: text
overlap with arXiv:1702.0565
Performance modelling of opportunistic forwarding with exact knowledge
The Delay Tolerant Networking paradigm aims to enable communications in disconnected environments where traditional protocols would fail. Opportunistic networks are delay tolerant networks whose nodes are typically the users\u27 personal mobile devices. Communications in an opportunistic network rely on the mobility of users: each message is forwarded from node to node, according to a hop-by-hop decision process that selects the node that is better suited for bringing the message closer to its destination. Despite the variety of forwarding protocols that have been proposed in the recent years, there is no reference framework for the performance modelling of opportunistic forwarding. In this paper we start to fill this gap by proposing an analytical model for the expected delay and the expected number of hops experienced by messages when delivered in an opportunistic fashion. This model seamlessly integrates both social-aware and social-oblivious single-copy forwarding protocols, as well as different hypotheses for user contact dynamics. The proposed framework is used to derive bounds on the expected delay under homogeneous and heterogeneous contact patterns. We found that, in heterogeneous settings, finite expected delay can be guaranteed not only when nodes\u27 inter-meeting times follow an exponential or power law with exponential cut-off distribution, but also when they are power law distributed, as long as weaker conditions than those derived by Chaintreau et al. [1] for the homogeneous scenario are satisfied
Congestion aware forwarding in delay tolerant and social opportunistic networks
We propose an approach for opportunistic forwarding that supports optimization of multipoint high volume data flow transfer while maintaining high buffer availability and low delays. This paper explores a number of social, buffer and delay heuristics to offload the traffic from congested parts of the network and spread it over less congested parts of the network in order to keep low delays, high success ratios and high availability of nodes. We conduct an extensive set of experiments for assessing the performance of four newly proposed heuristics and compare them with Epidemic, Prophet, Spay and Wait and Spay and Focus protocols over real connectivity driven traces (RollerNet) and with a realistic publish subscribe filecasting application. We look into success ratio of answered queries, download times (delays) and availability of buffer across eight protocols for varying congestion levels in the face of increasing number of publishers and topic popularity. We show that all of our combined metrics perform better than Epidemic protocol, Prophet, Spray and Wait, Spray and Focus and our previous prototype across all the assessed criteria
The Quest for a Killer App for Opportunistic and Delay Tolerant Networks (Invited Paper)
Delay Tolerant Networking (DTN) has attracted a lot of attention from the research community in recent years. Much work have been done regarding network architectures and algorithms for routing and forwarding in such networks. At the same time as many show enthusiasm for this exciting new research area there are also many sceptics, who question the usefulness of research in this area. In the past, we have seen other research areas become over-hyped and later die out as there was no killer app for them that made them useful in real scenarios. Real deployments of DTN systems have so far mostly been limited to a few niche scenarios, where they have been done as proof-of-concept field tests in research projects. In this paper, we embark upon a quest to find out what characterizes a potential killer applications for DTNs.
Are there applications and situations where DTNs provide
services that could not be achieved otherwise, or have potential to do it in a better way than other techniques? Further, we highlight some of the main challenges that needs to be solved to realize these applications and make DTNs a part of the mainstream network landscape
Store, carry and forward for energy efficiency in multi-hop cellular networks with mobile relays
Abstract The wide scale adoption of smartphones is
boosting cellular data traffic with the consequent capacity
constraints of cellular systems and increase in energy
consumption. A significant portion of cellular data traffic can be
deemed as delay tolerant. Such tolerance offers possibilities for
designing novel communications and networking solutions that
can accommodate the delay tolerant cellular data traffic while
reducing their impact on the overall cellular capacity and energy
consumption. In this context, this work studies the use of
opportunistic store, carry and forward techniques in Multi-Hop
Cellular Networks (MCN) to reduce energy consumption for
delay tolerant traffic. The study focuses on two-hop MCN
networks using mobile relays (MCN-MR), and identifies the
optimum mobile relay location and the location from which the
relay should start forwarding the information to the cellular base
station in order to minimize the overall energy consumption. The
study shows that the use of opportunistic store, carry and
forward techniques in MCN-MR can significantly reduce energy
consumption compared to other solutions, including traditional
single-hop cellular systems or direct contact store, carry and
forward solutions.This work is supported in part by the Spanish Ministry of Economy and Competitiveness and FEDER funds (TEC2011–26109)and the Local Government of Valencia with reference ACIF/2010/161 and BEFPI/2012/06
Opportunistic Networking for Improving the Energy Efficiency of Multi-Hop Cellular Networks
Relaying technologies can help address the capacity
and energy-efficiency challenges faced by cellular networks as a
result of the rapid increase in mobile data consumption. A nonnegligible
portion of such consumption corresponds to delay
tolerant services. This delay tolerance offers the possibility for
opportunistic networking to exploit contact opportunities
between mobile devices in order to reduce the impact of data
traffic on the cellular capacity and energy-efficiency without
sacrificing the end-user quality of service. In this context, this
paper investigates the use of opportunistic forwarding in MCNMR
(Multi-hop Cellular Networks with Mobile Relays) to reduce
energy consumption in the case of delay tolerant services. The
study proposes to exploit context information provided at a low
cost by the cellular infrastructure to efficiently select the
forwarding node in a two-hop MCN-MR scenario. The proposed
solution results in significant energy savings compared to
traditional single-hop cellular communications and other
forwarding solutions reported in the literatureThis work is supported in part by the Spanish Ministry of
Economy and Competitiveness and FEDER funds (TEC201126109),and the Local Government of Valencia with reference
ACIF/2010/161 and BEFPI/2012/06
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