A General Framework to Construct Stationary Mobility Models for the Simulation of Mobile Networks

Electr. Eng. & Comput. Sci. Dept., Michigan Univ., Ann Arbor, MI, USA
IEEE Transactions on Mobile Computing (Impact Factor: 2.54). 08/2006; 5(7):860- 871. DOI: 10.1109/TMC.2006.89
Source: IEEE Xplore


Simulation has become an indispensable tool in the design and evaluation of mobile systems. By using mobility models that describe constituent movement, one can explore large systems, producing repeatable results for comparison between alternatives. In this paper, we show that a large class of mobility models - including all those in which nodal speed and distance or destination are chosen independently - have a transient period in which the average node speed decreases until converging to some long-term average. This speed decay provides an unsound basis for simulation studies that collect results averaged over time, complicating the experimental process. In this paper, we derive a general framework for describing this decay and apply it to a number of cases. Furthermore, this framework allows us to transform a given mobility model into a stationary one by initializing the simulation using the steady-state speed distribution and using the original speed distribution subsequently. This transformation completely eliminates the transient period and the decay in average node speed and, thus, provides sound models for the simulation of mobile systems.

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Available from: Mingyan Liu, Mar 15, 2014
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    • "Since the performance tests should be done in the steady states, the non-steady states should be minimized for efficient simulations. For this purpose, several analytical techniques have been proposed [18]–[23]. In Ref. [18], Yoon et al. have focused on the node velocity distribution in the RWP model and shown the presence of the harmful effects before the convergence. "
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    ABSTRACT: In mobile wireless networks such as WSNs, WMNs and MANETs, movement of sensor nodes, clients and relay nodes has a great impact on the performance. Nevertheless, geography is too simplified in random-based mobility models such as RWP, while it is unrealistic to prepare trace-based mobility patterns for potential combinations of geography and mobility. To fulfill the gap, this paper provides a new method to automatically generate natural mobility patterns realizing designated node distributions. The goal of this work is to synthesize the movement patterns that can capture real (or intentional) node distributions. The method determines the probabilities of choosing waypoints from the subregions, satisfying the given node distributions. For this purpose, the relationship between the probabilities and node distributions is analyzed. Based on the analysis, the problem is formulated as an optimization problem of minimizing the error from the designated node distribution. Since the problem has non-linear constraints, a heuristic algorithm is designed to derive the near-optimal solutions. Several experiments have been conducted to show that a variety of node distributions could be realized in the proposed mobility model where the maximum error from the given node distributions was around 0.5%. Additionally, a case study has been conducted to show the applicability of the method.
    IEEE 8th International Conference on Mobile Adhoc and Sensor Systems, MASS 2011, Valencia, Spain, October 17-22, 2011; 01/2011
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    • "Though this is critical to our analysis, it is not an unreasonable assumption. It is well-known that a mobility model is meaningful for network evaluation only if it exhibits stationarity [20]. In particular, it is obvious that the random-walk, the random-waypoint model, and their variants are known to be stationary under proper choice of parameters. "
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    ABSTRACT: Consider an intermittently-connected mobile network consisting of n relay nodes, a single source node, and m destination nodes exhibiting a stochastic model for mobility. Each mobile relay node is also equipped with finite storage. We seek to analyze the performance of Multicast enabled by Network Coding in such a network under the store, carry, and forward paradigm, and compare its performance to a simple custodial-multicast scheme. Though accurate analysis of network-coded multicast is very complicated, we derive a provable way to obtain tight bounds on the performance. We then develop a queuing-theoretic framework to analyze the steady-state throughput performance of the network-coded scheme under this setup, which is then solved iteratively. The framework developed thus enables speedy evaluation of the communication protocols described. Our analytical results, supported by simulation studies, show that the network-coding-based scheme offers considerable improvement for the case when the storage size of the relay nodes is small and when the number of destination nodes is large.
    Modeling and Optimization in Mobile, Ad Hoc and Wireless Networks (WiOpt), 2010 Proceedings of the 8th International Symposium on; 07/2010
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    • "Earlier work on video communication over highway (not urban) VANETs [15] considered the problem of triggering remote video sources in the event of forward traffic congestion. The main problems in triggering [28] are how to reduce the number of messages reaching the remote camera(s) and how to reduce the latency in reaching those cameras (by reducing the number of hops), which is principally an issue of protocol design. In an emergency scenario as opposed to obtaining forward views of traffic congestion, it may be that video sources can be locally generated. "
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    ABSTRACT: Vehicle Ad-hoc Network (VANET) is a kind of Mobile Ad-hoc Network (MANET) that establishes wireless connection between cars. In VANETs and MANETs, the topology of the network changes very often, therefore implementation of efficient routing protocols is very important problem. In MANETs, the Random Waypoint (RW) model is used as a simulation model for generating node mobility pattern. On the other hand, in VANETs, the mobility patterns of nodes is restricted along the roads, and is affected by the movement of neighbour nodes. In this paper, we present a simulation system for VANET called CAVENET (Cellular Automaton based VEhicular NETwork). In CAVENET, the mobility patterns of nodes are generated by an 1-dimensional cellular automata. We improved CAVENET and implemented some routing protocols. We investigated the performance of the implemented routing protocols by CAVENET. The simulation results have shown that DYMO protocol has better performance than AODV and OLSR protocols.
    Mobile Information Systems 01/2010; 6(3):213-227. DOI:10.3233/MIS-2010-0100 · 0.95 Impact Factor
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