Mobility models characterize the movements of mobile users with respect to their location, velocity and direction over a period of time. These models play a vital role in the design of
Mobile Ad Hoc Networks(MANET). Most of the times simulators play a significant role in testing the features of mobile ad hoc networks. Simulators like
(NS,
QualNet
QualNet is a commercial network simulation tool owned by Keysight Technologies (formerly Scalable Network Technologies).
QualNet uses parallel discrete event simulation technology to model various layers of the network stack including the ph ...
, etc.) allow the users to choose the mobility models as these models represent the movements of nodes or users. As the mobile nodes move in different directions, it becomes imperative to characterize their movements ''vis-à-vis'' to standard models. The mobility models proposed in literature have varying degrees of realism i.e. from random patterns to realistic patterns. Thus these models contribute significantly while testing the protocols for mobile ad hoc networks.
Background and terminology
The study of large and complex networks is possible by experimenting on a simulator rather than on analytical studies. The relatively new form of networks like
Mobile Ad Hoc Networks(MANET),
Vehicular Ad Hoc Networks (VANET), etc. are characterized by nodes which are autonomous and dynamic in nature. Thus it becomes very essential to capture their movements so that the corresponding simulations results are nearer to reality. Mobility models are basically classified as stochastic, detailed, Hybrid and Trace based Realistic models.
* The stochastic models are based on random movements and the nodes are free to move in any direction. Example include Random waypoint model, Random walk and Random direction model.
* The detailed models are tailored for specific scenarios. This could include meetings, library and classroom scenarios. Example includes Street random waypoint (STRAW),
* The Hybrid models try to strike a balance between realism (Detailed models) and freedom of movements(Stochastic models). Examples include Reference point group mobility model, Manhattan mobility model and Freeway mobility model.
* The Real trace models contain a collection of movements of realistic users based on specific scenarios. Example includes CRAWDAD.
Mobility models
For mobility modelling, the behavior or activity of a user's movement can be described using both analytical and simulation models. The input to analytical mobility models are simplifying assumptions regarding the movement behaviors of users. Such models can provide performance parameters for simple cases through mathematical calculations. In contrast, simulation models consider more detailed and realistic mobility scenarios. Such models can derive valuable solutions for more complex cases. Typical mobility
models include
*
Random waypoint model In mobility management, the random waypoint model is a random model for the movement of mobile users, and how their location, velocity and acceleration change over time. Mobility models are used for simulation purposes when new network protocols ar ...
*
Random walk
In mathematics, a random walk, sometimes known as a drunkard's walk, is a stochastic process that describes a path that consists of a succession of random steps on some Space (mathematics), mathematical space.
An elementary example of a rand ...
model
*
Random direction model In mobility management, the random waypoint model is a random model for the movement of mobile users, and how their location, velocity and acceleration change over time. Mobility models are used for simulation purposes when new network protocols ar ...
* Street random waypoint
*Reference point group model (RPGM)
*
Manhattan mobility model {{more citations needed, date=February 2009
The Manhattan mobility model is a guide which leads the driver of a vehicle on the correct path. It is an urban type of mobility model for vehicular ad-hoc networks (VANET). The Manhattan mobility mode ...
*Freeway mobility model
Metrics for Mobility Models
Mobility model metrics are useful to study the impact of mobility models on the performances of mobile ad hoc networks. Metrics are usually classified as mobility metrics, connectivity graph metrics and protocol performance metrics.
* The mobility metrics usually speaks about the mobility patterns. These include spatial dependence, temporal dependence, relative speed and geographic restrictions.
* The connectivity graph metrics speaks about the number of link changes, link duration, path duration and path availability.
* The protocol performance metrics speaks about throughput and routing overhead.
See also
*
Mobility management
Mobility management is one of the major functions of a GSM or
a UMTS network that allows mobile phones to work. The aim of mobility management is to track where the subscribers are, allowing calls, SMS and other mobile phone services to be del ...
*
Mobile ad hoc network
A wireless ad hoc network (WANET) or mobile ad hoc network (MANET) is a decentralized type of wireless network. The network is ad hoc because it does not rely on a pre-existing infrastructure, such as router (computing), routers or wireless acces ...
(MANET)
*
Radio propagation model
Radio propagation is the behavior of radio waves as they travel, or are propagated, from one point to another in vacuum, or into various parts of the atmosphere.
As a form of electromagnetic radiation, like light waves, radio waves are affect ...
s
*
Network simulation
In computer network research, network simulation is a technique whereby a software program replicates the behavior of a real network. This is achieved by calculating the interactions between the different network entities such as routers, switc ...
*
Network simulator
In computer network research, network simulation is a technique whereby a software program replicates the behavior of a real network. This is achieved by calculating the interactions between the different network entities such as routers, switc ...
*
Network traffic simulation Network traffic simulation is a process used in telecommunications engineering to measure the efficiency of a communications network.
Overview
Telecommunications systems are complex real-world systems, containing many different components which in ...
*
Radio resource management Radio resource management (RRM) is the system level management of co-channel interference, radio resources, and other radio transmission characteristics in wireless communication systems, for example cellular networks, wireless local area networks, ...
(RRM)
*
Traffic generation model
A traffic generation model is a stochastic model of the traffic flows or data sources in a communication network, for example a cellular network or a computer network. A packet generation model is a traffic generation model of the packet flows o ...
References
{{telecommunications
GSM standard
Wireless networking