9,430 research outputs found
An adaptive quasi harmonic broadcasting scheme with optimal bandwidth requirement
The aim of Harmonic Broadcasting protocol is to reduce the bandwidth usage in
video-on-demand service where a video is divided into some equal sized segments
and every segment is repeatedly transmitted over a number of channels that
follows harmonic series for channel bandwidth assignment. As the bandwidth of
channels differs from each other and users can join at any time to these
multicast channels, they may experience a synchronization problem between
download and playback. To deal with this issue, some schemes have been
proposed, however, at the cost of additional or wastage of bandwidth or sudden
extreme bandwidth requirement. In this paper we present an adaptive quasi
harmonic broadcasting scheme (AQHB) which delivers all data segment on time
that is the download and playback synchronization problem is eliminated while
keeping the bandwidth consumption as same as traditional harmonic broadcasting
scheme without cost of any additional or wastage of bandwidth. It also ensures
the video server not to increase the channel bandwidth suddenly that is, also
eliminates the sudden buffer requirement at the client side. We present several
analytical results to exhibit the efficiency of our proposed broadcasting
scheme over the existing ones.Comment: IEEE International Conference on Informatics, Electronics & Vision
(ICIEV), 2013, 6pages, 8 figure
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Improving multiple broadcasting of multimedia traffic in wireless ad-hoc networks
The increasing use of multimedia streaming applications in addition with advent of internet television and radio, demands from today's wireless networks to handle with reliability multiple broadcasting and multicasting sources. However, the way that 802.11 standard, which is the primary technology in wireless networking, handle this type of traffic raises a series of problems mainly related to the lack of an effective feedback mechanism. This lack in turn, limits the capability of random backoff process to eliminate collisions and reduce reliability and fairness. This inherited drawback of the standard is affecting the way broadcast and multicast traffic is transmitted as well as the overall performance of the network. In this paper initially we are highlighting the drawback of the IEEE 802.11 MAC algorithm in handling multiple stations âmedia typeâ data broadcasting in an ad-hoc wireless network. Then, we propose two different approaches in alleviating these problems. The first approach is the simple linear increase of the contention window (CW) while the second propose a linear increase of the CW implementing an exclusive backoff number allocation (EBNA) algorithm. In addition we are modifying the 802.11 medium access control (MAC) algorithm to use the clear to send to self (CTS-to-Self) protection mechanism prior to every transmission. Both the above techniques are simulated and compared with the classic 802.11 MAC. The results show that the overall performance of the network can be improved using these alternative MAC methods
A vehicle-to-infrastructure communication based algorithm for urban traffic control
We present in this paper a new algorithm for urban traffic light control with
mixed traffic (communicating and non communicating vehicles) and mixed
infrastructure (equipped and unequipped junctions). We call equipped junction
here a junction with a traffic light signal (TLS) controlled by a road side
unit (RSU). On such a junction, the RSU manifests its connectedness to equipped
vehicles by broadcasting its communication address and geographical
coordinates. The RSU builds a map of connected vehicles approaching and leaving
the junction. The algorithm allows the RSU to select a traffic phase, based on
the built map. The selected traffic phase is applied by the TLS; and both
equipped and unequipped vehicles must respect it. The traffic management is in
feedback on the traffic demand of communicating vehicles. We simulated the
vehicular traffic as well as the communications. The two simulations are
combined in a closed loop with visualization and monitoring interfaces. Several
indicators on vehicular traffic (mean travel time, ended vehicles) and IEEE
802.11p communication performances (end-to-end delay, throughput) are derived
and illustrated in three dimension maps. We then extended the traffic control
to a urban road network where we also varied the number of equipped junctions.
Other indicators are shown for road traffic performances in the road network
case, where high gains are experienced in the simulation results.Comment: 6 page
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