38,380 research outputs found
Let the Tree Bloom: Scalable Opportunistic Routing with ORPL
Routing in battery-operated wireless networks is challenging, posing a tradeoff between energy and latency. Previous work has shown that opportunistic routing can achieve low-latency data collection in duty-cycled networks. However, applications are now considered where nodes are not only periodic data sources, but rather addressable end points generating traffic with arbitrary patterns.
We present ORPL, an opportunistic routing protocol that supports any-to-any, on-demand traffic. ORPL builds upon RPL, the standard protocol for low-power IPv6 networks. By combining RPL's tree-like topology with opportunistic routing, ORPL forwards data to any destination based on the mere knowledge of the nodes' sub-tree. We use bitmaps and Bloom filters to represent and propagate this information in a space-efficient way, making ORPL scale to large networks of addressable nodes. Our results in a 135-node testbed show that ORPL outperforms a number of state-of-the-art solutions including RPL and CTP, conciliating a sub-second latency and a sub-percent duty cycle. ORPL also increases robustness and scalability, addressing the whole network reliably through a 64-byte Bloom filter, where RPL needs kilobytes of routing tables for the same task
MOSDEN: A Scalable Mobile Collaborative Platform for Opportunistic Sensing Applications
Mobile smartphones along with embedded sensors have become an efficient
enabler for various mobile applications including opportunistic sensing. The
hi-tech advances in smartphones are opening up a world of possibilities. This
paper proposes a mobile collaborative platform called MOSDEN that enables and
supports opportunistic sensing at run time. MOSDEN captures and shares sensor
data across multiple apps, smartphones and users. MOSDEN supports the emerging
trend of separating sensors from application-specific processing, storing and
sharing. MOSDEN promotes reuse and re-purposing of sensor data hence reducing
the efforts in developing novel opportunistic sensing applications. MOSDEN has
been implemented on Android-based smartphones and tablets. Experimental
evaluations validate the scalability and energy efficiency of MOSDEN and its
suitability towards real world applications. The results of evaluation and
lessons learned are presented and discussed in this paper.Comment: Accepted to be published in Transactions on Collaborative Computing,
2014. arXiv admin note: substantial text overlap with arXiv:1310.405
Opportunistic Collaborative Beamforming with One-Bit Feedback
An energy-efficient opportunistic collaborative beamformer with one-bit
feedback is proposed for ad hoc sensor networks over Rayleigh fading channels.
In contrast to conventional collaborative beamforming schemes in which each
source node uses channel state information to correct its local carrier offset
and channel phase, the proposed beamforming scheme opportunistically selects a
subset of source nodes whose received signals combine in a quasi-coherent
manner at the intended receiver. No local phase-precompensation is performed by
the nodes in the opportunistic collaborative beamformer. As a result, each node
requires only one-bit of feedback from the destination in order to determine if
it should or shouldn't participate in the collaborative beamformer. Theoretical
analysis shows that the received signal power obtained with the proposed
beamforming scheme scales linearly with the number of available source nodes.
Since the the optimal node selection rule requires an exhaustive search over
all possible subsets of source nodes, two low-complexity selection algorithms
are developed. Simulation results confirm the effectiveness of opportunistic
collaborative beamforming with the low-complexity selection algorithms.Comment: Proceedings of the Ninth IEEE Workshop on Signal Processing Advances
in Wireless Communications, Recife, Brazil, July 6-9, 200
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
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