62,868 research outputs found
Impact of Obstacles on the Degree of Mobile Ad Hoc Connection Graphs
What is the impact of obstacles on the graphs of connections between stations
in Mobile Ad hoc Networks? In order to answer, at least partially, this
question, the first step is to define both an environment with obstacles and a
mobility model for the stations in such an environment. The present paper
focuses on a new way of considering the mobility within environments with
obstacles, while keeping the core ideas of the well-known Random WayPoint
mobility model (a.k.a RWP). Based on a mesh-partitioning of the space, we
propose a new model called RSP-O-G for which we compute the spatial
distribution of stations and analyse how the presence of obstacles impacts this
distribution compared to the distribution when no obstacles are present.
Coupled with a simple model of radio propagation, and according to the density
of stations in the environment, we study the mean degree of the connection
graphs corresponding to such mobile ad hoc networks
The impact of propagation environment and traffic load on the performance of routing protocols in ad hoc networks
Wireless networks are characterized by a dynamic topology triggered by the
nodes mobility. Thus, the wireless multi-hops connection and the channel do not
have a determinist behaviour such as: interference or multiple paths. Moreover,
the nodes' invisibility makes the wireless channel difficult to detect. This
wireless networks' behaviour should be scrutinized. In our study, we mainly
focus on radio propagation models by observing the evolution of the routing
layer's performances in terms of the characteristics of the physical layer. For
this purpose, we first examine and then display the simulation findings of the
impact of different radio propagation models on the performance of ad hoc
networks. To fully understand how these various radio models influence the
networks performance, we have compared the performances of several routing
protocols (DSR, AODV, and DSDV) for each propagation model. To complete our
study, a comparison of energy performance based routing protocols and
propagation models are presented. In order to reach credible results, we
focused on the notion of nodes' speed and the number of connections by using
the well known network simulator NS-2.Comment: 13 pages, 5 figures, International Journal of Distributed and
Parallel Systems (IJDPS) Vol.3, No.1, January 201
Simulation based comparison of routing protocols in wireless multihop adhoc networks
Routing protocols are responsible for providing reliable communication between the source and destination nodes. The performance of these protocols in the ad hoc network family is influenced by several factors such as mobility model, traffic load, transmission range, and the number of mobile nodes which represents a great issue. Several simulation studies have explored routing protocol with performance parameters, but few relate to various protocols concerning routing and Quality of Service (QoS) metrics. This paper presents a simulation-based comparison of proactive, reactive, and multipath routing protocols in mobile ad hoc networks (MANETs). Specifically, the performance of AODV, DSDV, and AOMDV protocols are evaluated and analyzed in the presence of varying the number of mobile nodes, pause time, and traffic connection numbers. Moreover, Routing and QoS performance metrics such as normalized routing load, routing packet, packet delivery ratio, packet drop, end-to-end delay, and throughput are measured to conduct a performance comparison between three routing protocols. Simulation results indicate that AODV outperforms the DSDV and AOMDV protocols in most of the metrics. AOMDV is better than DSDV in terms of end-to-end delay. DSDV provides lower throughput performance results. Network topology parameters have a slight impact on AODV Performance
Research on Wireless Multi-hop Networks: Current State and Challenges
Wireless multi-hop networks, in various forms and under various names, are
being increasingly used in military and civilian applications. Studying
connectivity and capacity of these networks is an important problem. The
scaling behavior of connectivity and capacity when the network becomes
sufficiently large is of particular interest. In this position paper, we
briefly overview recent development and discuss research challenges and
opportunities in the area, with a focus on the network connectivity.Comment: invited position paper to International Conference on Computing,
Networking and Communications, Hawaii, USA, 201
Quantifying Link Stability in Ad Hoc Wireless Networks Subject to Ornstein-Uhlenbeck Mobility
The performance of mobile ad hoc networks in general and that of the routing
algorithm, in particular, can be heavily affected by the intrinsic dynamic
nature of the underlying topology. In this paper, we build a new
analytical/numerical framework that characterizes nodes' mobility and the
evolution of links between them. This formulation is based on a stationary
Markov chain representation of link connectivity. The existence of a link
between two nodes depends on their distance, which is governed by the mobility
model. In our analysis, nodes move randomly according to an Ornstein-Uhlenbeck
process using one tuning parameter to obtain different levels of randomness in
the mobility pattern. Finally, we propose an entropy-rate-based metric that
quantifies link uncertainty and evaluates its stability. Numerical results show
that the proposed approach can accurately reflect the random mobility in the
network and fully captures the link dynamics. It may thus be considered a
valuable performance metric for the evaluation of the link stability and
connectivity in these networks.Comment: 6 pages, 4 figures, Submitted to IEEE International Conference on
Communications 201
Effective link operation duration: a new routing metric for mobile ad hoc networks
The dynamic topology of mobile ad hoc networks (MANETs) is caused by node mobility and fading of the wireless link. Link reliability is often measured by the estimated lifetime and the stability of a link. In this paper we propose that the stability of a link can be represented by the time duration in which the two nodes at each end of a link are within each otherâs transmission range and the fading is above an acceptable threshold. A novel routing metric, called effective link operation duration (ELOD), is proposed and implemented into AODV (AODV-ELOD). Simulation results show that proposed AODVELOD outperforms both AODV and the Flow Oriented Routing Protocol (FORP)
Spatial networks with wireless applications
Many networks have nodes located in physical space, with links more common
between closely spaced pairs of nodes. For example, the nodes could be wireless
devices and links communication channels in a wireless mesh network. We
describe recent work involving such networks, considering effects due to the
geometry (convex,non-convex, and fractal), node distribution,
distance-dependent link probability, mobility, directivity and interference.Comment: Review article- an amended version with a new title from the origina
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