36,970 research outputs found
Setting the parameters right for two-hop IEEE 802.11e ad hoc networks
Two-hop ad-hoc networks, in which some nodes forward traffic for multiple sources, with which they also compete for channel access suffer from large queues building up in bottleneck nodes. This problem can often be alleviated by using IEEE 802.11e to give preferential treatment to bottleneck nodes. Previous results have shown that differentiation parameters can be used to allocate capacity in a more efficient way in the two-hop scenario. However, the overall throughput of the bottleneck may differ considerably, depending on the differentiation method used. By applying a very fast and accurate analysis method, based on steady-state analysis of an QBD-type infinite Markov chain, we find the maximum throughput that is possible per differentiation parameter. All possible parameter settings are explored with respect to the maximum throughput conditioned on a maximum buffer occupancy. This design space exploration cannot be done with network simulators like NS2 or Opnet, as each simulation run simply takes to long.\ud
The results, which have been validated by detailed simulations, show that by differentiating TXOP it is possible to achieve a throughput that is about 50% larger than when differentiating AIFS and CW_min.\u
On Capacity and Delay of Multi-channel Wireless Networks with Infrastructure Support
In this paper, we propose a novel multi-channel network with infrastructure
support, called an MC-IS network, which has not been studied in the literature.
To the best of our knowledge, we are the first to study such an MC-IS network.
Our proposed MC-IS network has a number of advantages over three existing
conventional networks, namely a single-channel wireless ad hoc network (called
an SC-AH network), a multi-channel wireless ad hoc network (called an MC-AH
network) and a single-channel network with infrastructure support (called an
SC-IS network). In particular, the network capacity of our proposed MC-IS
network is times higher than that of an SC-AH network and an
MC-AH network and the same as that of an SC-IS network, where is the number
of nodes in the network. The average delay of our MC-IS network is times lower than that of an SC-AH network and an MC-AH network, and
times lower than the average delay of an SC-IS network, where
and denote the number of channels dedicated for infrastructure
communications and the number of interfaces mounted at each infrastructure
node, respectively. Our analysis on an MC-IS network equipped with
omni-directional antennas only has been extended to an MC-IS network equipped
with directional antennas only, which are named as an MC-IS-DA network. We show
that an MC-IS-DA network has an even lower delay of compared with an SC-IS network and our
MC-IS network. For example, when and , an
MC-IS-DA network can further reduce the delay by 24 times lower that of an
MC-IS network and reduce the delay by 288 times lower than that of an SC-IS
network.Comment: accepted, IEEE Transactions on Vehicular Technology, 201
Multi-channel Wireless Networks with Infrastructure Support: Capacity and Delay
In this paper, we propose a novel multi-channel network with infrastructure
support, called an \textit{MC-IS} network, which has not been studied in the
literature. To the best of our knowledge, we are the first to study such an
\textit{MC-IS} network. Our \textit{MC-IS} network is equipped with a number of
infrastructure nodes which can communicate with common nodes using a number of
channels where a communication between a common node and an infrastructure node
is called an infrastructure communication and a communication between two
common nodes is called an ad-hoc communication. Our proposed \textit{MC-IS}
network has a number of advantages over three existing conventional networks,
namely a single-channel wireless ad hoc network (called an \textit{SC-AH}
network), a multi-channel wireless ad hoc network (called an \textit{MC-AH}
network) and a single-channel network with infrastructure support (called an
\textit{SC-IS} network). In particular, the \textit{network capacity} of our
proposed \textit{MC-IS} network is times higher than that of
an \textit{SC-AH} network and an \textit{MC-AH} network and the same as that of
an \textit{SC-IS} network, where is the number of nodes in the network. The
\textit{average delay} of our \textit{MC-IS} network is times
lower than that of an \textit{SC-AH} network and an \textit{MC-AH} network, and
times lower than the average delay of an \textit{SC-IS} network,
where and denote the number of channels dedicated for infrastructure
communications and the number of interfaces mounted at each infrastructure
node, respectively.Comment: 12 pages, 6 figures, 3 table
Optimized network structure and routing metric in wireless multihop ad hoc communication
Inspired by the Statistical Physics of complex networks, wireless multihop ad
hoc communication networks are considered in abstracted form. Since such
engineered networks are able to modify their structure via topology control, we
search for optimized network structures, which maximize the end-to-end
throughput performance. A modified version of betweenness centrality is
introduced and shown to be very relevant for the respective modeling. The
calculated optimized network structures lead to a significant increase of the
end-to-end throughput. The discussion of the resulting structural properties
reveals that it will be almost impossible to construct these optimized
topologies in a technologically efficient distributive manner. However, the
modified betweenness centrality also allows to propose a new routing metric for
the end-to-end communication traffic. This approach leads to an even larger
increase of throughput capacity and is easily implementable in a
technologically relevant manner.Comment: 25 pages, v2: fixed one small typo in the 'authors' fiel
Neighbour coverage: a dynamic probabilistic route discovery for mobile ad hoc networks
Blind flooding is extensively use in ad hoc routing protocols for on-demand route discovery, where a mobile node blindly rebroadcasts received route request (RREQ) packets until a route to a particular destination is established. This can potentially lead to high channel contention, causing redundant retransmissions and thus excessive packet collisions in the network. Such a phenomenon induces what is known as broadcast storm problem, which has been shown to greatly increase the network communication overhead and end-to-end delay. In this paper, we show that the deleterious impact of such a problem can be reduced if measures are taken during the dissemination of RREQ packets. We propose a generic probabilistic method for route discovery, that is simple to implement and can significantly reduce the overhead associated with the dissemination of RREQs. Our analysis reveals that equipping AODV with probabilistic route discovery can result in significant reduction of routing control overhead while achieving good throughput
Impact of Correlated Mobility on Delay-Throughput Performance in Mobile Ad-Hoc Networks
AbstractâWe extend the analysis of the scaling laws of wireless ad hoc networks to the case of correlated nodes movements, which are commonly found in real mobility processes. We consider a simple version of the Reference Point Group Mobility model, in which nodes belonging to the same group are constrained to lie in a disc area, whose center moves uniformly across the network according to the i.i.d. model. We assume fast mobility conditions, and take as primary goal the maximization of pernode throughput. We discover that correlated node movements have huge impact on asymptotic throughput and delay, and can sometimes lead to better performance than the one achievable under independent nodes movements. I. INTRODUCTION AND RELATED WORK In the last few years the store-carry-forward communication paradigm, which allows nodes to physically carry buffered dat
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