48 research outputs found
Evaluation of HTTP/DASH Adaptation Algorithms on Vehicular Networks
Video streaming currently accounts for the majority of Internet traffic. One
factor that enables video streaming is HTTP Adaptive Streaming (HAS), that
allows the users to stream video using a bit rate that closely matches the
available bandwidth from the server to the client. MPEG Dynamic Adaptive
Streaming over HTTP (DASH) is a widely used standard, that allows the clients
to select the resolution to download based on their own estimations. The
algorithm for determining the next segment in a DASH stream is not partof the
standard, but it is an important factor in the resulting playback quality.
Nowadays vehicles are increasingly equipped with mobile communication devices,
and in-vehicle multimedia entertainment systems. In this paper, we evaluate the
performance of various DASH adaptation algorithms over a vehicular network. We
present detailed simulation results highlighting the advantages and
disadvantages of various adaptation algorithms in delivering video content to
vehicular users, and we show how the different adaptation algorithms perform in
terms of throughput, playback interruption time, and number of interruptions
A Load Balancing Algorithm for Resource Allocation in IEEE 802.15.4e Networks
The recently created IETF 6TiSCH working group combines the high reliability
and low-energy consumption of IEEE 802.15.4e Time Slotted Channel Hopping with
IPv6 for industrial Internet of Things. We propose a distributed link
scheduling algorithm, called Local Voting, for 6TiSCH networks that adapts the
schedule to the network conditions. The algorithm tries to equalize the link
load (defined as the ratio of the queue length over the number of allocated
cells) through cell reallocation. Local Voting calculates the number of cells
to be added or released by the 6TiSCH Operation Sublayer (6top). Compared to a
representative algorithm from the literature, Local Voting provides
simultaneously high reliability and low end-to-end latency while consuming
significantly less energy. Its performance has been examined and compared to
On-the-fly algorithm in 6TiSCH simulator by modeling an industrial environment
with 50 sensors
Towards Optimal Distributed Node Scheduling in a Multihop Wireless Network through Local Voting
In a multihop wireless network, it is crucial but challenging to schedule
transmissions in an efficient and fair manner. In this paper, a novel
distributed node scheduling algorithm, called Local Voting, is proposed. This
algorithm tries to semi-equalize the load (defined as the ratio of the queue
length over the number of allocated slots) through slot reallocation based on
local information exchange. The algorithm stems from the finding that the
shortest delivery time or delay is obtained when the load is semi-equalized
throughout the network. In addition, we prove that, with Local Voting, the
network system converges asymptotically towards the optimal scheduling.
Moreover, through extensive simulations, the performance of Local Voting is
further investigated in comparison with several representative scheduling
algorithms from the literature. Simulation results show that the proposed
algorithm achieves better performance than the other distributed algorithms in
terms of average delay, maximum delay, and fairness. Despite being distributed,
the performance of Local Voting is also found to be very close to a centralized
algorithm that is deemed to have the optimal performance
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Authentication in a layered security approach for mobile ad hoc networks
An ad hoc network is a collection of nodes that do not need to rely on a predefined infrastructure to keep the network connected. Nodes communicate amongst each other using wireless radios and operate by following a peer-to-peer network model. In this article we investigate authentication in a layered approach, which results to multiple lines of defense for mobile ad hoc networks. The layered security approach is described and design criteria for creating secure ad hoc network using multiple authentication protocols are analysed. The performance of several such known protocols, which are based on challenge-response techniques, is presented through simulation results