10,452 research outputs found

    Restricted Mobility Improves Delay-Throughput Trade-offs in Mobile Ad-Hoc Networks

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    In this paper we revisit two classes of mobility models which are widely used to repre-sent users ’ mobility in wireless networks: Random Waypoint (RWP) and Random Direction (RD). For both models we obtain systems of partial differential equations which describe the evolution of the users ’ distribution. For the RD model, we show how the equations can be solved analytically both in the stationary and transient regime adopting standard mathematical techniques. Our main contributions are i) simple expressions which relate the transient dura-tion to the model parameters; ii) the definition of a generalized random direction model whose stationary distribution of mobiles in the physical space corresponds to an assigned distribution

    Impact of Correlated Mobility on Delay-Throughput Performance in Mobile Ad-Hoc Networks

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    Abstract—We 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

    Fuzzy based load and energy aware multipath routing for mobile ad hoc networks

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    Routing is a challenging task in Mobile Ad hoc Networks (MANET) due to their dynamic topology and lack of central administration. As a consequence of un-predictable topology changes of such networks, routing protocols employed need to accurately capture the delay, load, available bandwidth and residual node energy at various locations of the network for effective energy and load balancing. This paper presents a fuzzy logic based scheme that ensures delay, load and energy aware routing to avoid congestion and minimise end-to-end delay in MANETs. In the proposed approach, forwarding delay, average load, available bandwidth and residual battery energy at a mobile node are given as inputs to a fuzzy inference engine to determine the traffic distribution possibility from that node based on the given fuzzy rules. Based on the output from the fuzzy system, traffic is distributed over fail-safe multiple routes to reduce the load at a congested node. Through simulation results, we show that our approach reduces end-to-end delay, packet drop and average energy consumption and increases packet delivery ratio for constant bit rate (CBR) traffic when compared with the popular Ad hoc On-demand Multipath Distance Vector (AOMDV) routing protocol

    Analysing End-to-End Packet Delay and Loss in mobile ad hoc networks for interactive audio applications

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    Colloque avec actes et comité de lecture. nationale.National audienceInteractive audio applications such as audio conferencing and telephony require high constraints on delay, jitter and loss. The packets of these applications must be received without significant loss, with low delay and jitter. When packet loss rate exceeds 10% and one way delay exceeds 150 ms, speech quality can be quite poor. Human conversation tolerates a maximum end-to-end delay of between 150 and 300 milliseconds. In addition, these packets must have a small delay variation to maintain constant rate for successive audio packets at the destination. In ad hoc networks, many factors such load traffic, codec bit rate, routing protocol configuration and mobility speed have an impact on packet loss rate, delays, and jitter which degrade the quality of the received audio signal. In this paper, we analysed how these factors influence packet delay and loss observed at the reciever side. A best knowledge of this behaviour is important to develop more effective mechanisms for dynamic adjustment of playout delays or throughput, in order to improve the perceptual quality of audio applications running in ad hoc networks. At the receiver side, we distinguish two operating phases of an audio flow, normal phase and reconfiguration phase. During a normal phase the flow reaches the destination from the source on the same route without link breakage, while during a reconfiguration phase, nodes move on the current route and the audio flow transfer is interrupted for delay required from a routing protocol to establish a new route towards the destination

    Performance Analysis of Traffic and Mobility Models on Mobile and Vehicular Ad Hoc Wireless Networks

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    Advances in wireless communication technology and the proliferation of mobile devices enable the capa- bilities of communicating with each other even in areas with no pre-existing communication infrastructure. Traffic and mobility models play an important role in evaluating the performance of these communication networks. Despite criticism and assumption from various researches on Transmission Control Protocols (TCP), weaknesses on Mobile Ad Hoc Network (MANET), and Vehicular Ad Hoc Network (VANET). A simulation was carried out to evaluate the performance of Constant Bit Rate, Variable Bit Rate and Transmission Control Protocol on MANET and VANET using DSR routing protocol. CBR, VBR, and TCP have different manufacturer operation mechanisms and these differences lead to significant performance of CBR and VBR over TCP with better throughput and less average maximal end-to-end delay. DSR was able to respond to link failure at low mobility which led to TCP’s performance in packets delivery
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