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Mobility Model
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 network, 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 (simulator), (NS, QualNet, 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 analy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 access points. Instead, each Node (networking), node participates in routing by Packet forwarding, forwarding data for other nodes. The determination of which nodes forward data is made dynamically on the basis of network connectivity and the routing algorithm in use. Such wireless networks lack the complexities of infrastructure setup and administration, enabling devices to create and join networks "on the fly". Each device in a MANET is free to move independently in any direction, and will therefore change its links to other devices frequently. Each must forward traffic unrelated to its own use, and therefore be a Router (computing), router. The primary challenge in building a MANET is equipping each device to continuously maintain the infor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ns (simulator)
ns (from network simulator) is a name for a series of discrete event network simulators, specifically ns-1, ns-2, and ns-3. All are discrete-event computer network simulators, primarily used in research and teaching. History ns-1 The first version of ns, known as ns-1, was developed at Lawrence Berkeley National Laboratory (LBNL) in the 1995-97 timeframe by Steve McCanne, Sally Floyd, Kevin Fall, and other contributors. This was known as the LBNL Network Simulator, and derived in 1989 from an earlier simulator known as REAL by S. Keshav. ns-2 Ns-2 began as a revision of ns-1. From 1997 to 2000, ns development was supported by DARPA through the VINT project at LBL, Xerox PARC, UC Berkeley, and USC/ISI. In 2000, ns-2 development was supported through DARPA with SAMAN and through NSF with CONSER, both at USC/ISI, in collaboration with other researchers including ACIRI. Features of NS2 1. It is a discrete event simulator for networking research. 2. It provides su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 physical layer of wireless radios. QualNet simulations may be customized to include terrain data, antenna patterns, experimental or specialized network protocols (ex mesh networking A mesh network is a local area network network topology, topology in which the infrastructure Node (networking), nodes (i.e. bridges, switches, and other infrastructure devices) connect directly, dynamically and non-hierarchically to as many othe ...), and mobility (nodes move during the simulation). Alternatives to QualNet include NS-2 and OPNET. QualNet was used since the early 2000s to research and develop wireless communication technologies. See also * Discrete Event Simulation * Network simulation References Wireless networking Compute ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vehicular Ad Hoc Network
A Vehicular ad hoc network (VANET) is a proposed type of mobile ad hoc network (MANET) involving road vehicles. VANETs were first proposed in 2001 as " car-to-car ad-hoc mobile communication and networking" applications, where networks could be formed and information could be relayed among cars. It has been shown that vehicle-to-vehicle and vehicle-to-roadside communications architectures could co-exist in VANETs to provide road safety, navigation, and other roadside services. VANETs could be a key part of the intelligent transportation systems (ITS) framework. Sometimes, VANETs are referred to as Intelligent Transportation Networks. They could evolve into a broader " Internet of vehicles". which itself could evolve into an "Internet of autonomous vehicles". While, in the early 2000s, VANETs were seen as a mere one-to-one application of MANET principles, they have since then developed into a field of research in their own right. By 2015, the term VANET became mostly synonymous wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 are evaluated. The random waypoint model was first proposed by Johnson and Maltz. It is one of the most popular mobility models to evaluate mobile ad hoc network (MANET) routing protocols, because of its simplicity and wide availability. In random-based mobility simulation models, the mobile nodes move randomly and freely without restrictions. To be more specific, the destination, speed and direction are all chosen randomly and independently of other nodes. This kind of model has been used in many simulation studies. Two variants, the random walk model and the random direction model are variants of the random waypoint model. Description of model The movement of nodes is governed in the following manner: Each node begins by pausing for a f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 random walk is the random walk on the integer number line \mathbb Z which starts at 0, and at each step moves +1 or −1 with equal probability. Other examples include the path traced by a molecule as it travels in a liquid or a gas (see Brownian motion), the search path of a foraging animal, or the price of a fluctuating random walk hypothesis, stock and the financial status of a gambler. Random walks have applications to engineering and many scientific fields including ecology, psychology, computer science, physics, chemistry, biology, economics, and sociology. The term ''random walk'' was first introduced by Karl Pearson in 1905. Realizations of random walks can be obtained by Monte Carlo Simulation, Monte Carlo simulation. Lattice random ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 are evaluated. The random waypoint model was first proposed by Johnson and Maltz. It is one of the most popular mobility models to evaluate mobile ad hoc network (MANET) routing protocols, because of its simplicity and wide availability. In random-based mobility simulation models, the mobile nodes move randomly and freely without restrictions. To be more specific, the destination, speed and direction are all chosen randomly and independently of other nodes. This kind of model has been used in many simulation studies. Two variants, the random walk model and the random direction model are variants of the random waypoint model. Description of model The movement of nodes is governed in the following manner: Each node begins by pausing for a f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 model uses a " grid road topology. It works optimally where streets are in an organized manner. In this mobility model, mobile nodes move in horizontal or vertical direction on an urban map. The Manhattan model employs a probabilistic approach in the selection of nodes movements since, at each intersection, a vehicle chooses to keep moving in the same direction. The probability of going straight is 0.5 and taking a left or right is 0.25 each. The Manhattan model is not suitable for highway systems. Although this model provides flexibility for the nodes to change the direction, it imposes geographic restrictions on node mobility. Important Characteristics of the Manhattan Mobility model * The mobile node is allowed to move along the grid o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 delivered to them. Location update procedure A GSM or UMTS network, like all cellular networks, is basically a radio network of individual cells, known as base stations. Each base station covers a small geographical area which is part of a uniquely identified location area. By integrating the coverage of each of these base stations, a cellular network provides a radio coverage over a much wider area. For GSM, a base station is called a base transceiver station (BTS), and for UMTS it is called a Node B. A group of base stations is named a location area, or a routing area. The location update procedure allows a mobile device to inform the cellular network whenever it moves from one location area to the next. Mobiles are responsible for dete ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 affected by the phenomena of reflection, refraction, diffraction, absorption, polarization, and scattering. Understanding the effects of varying conditions on radio propagation has many practical applications, from choosing frequencies for amateur radio communications, international shortwave broadcasters, to designing reliable mobile telephone systems, to radio navigation, to operation of radar systems. Several different types of propagation are used in practical radio transmission systems. '' Line-of-sight propagation'' means radio waves which travel in a straight line from the transmitting antenna to the receiving antenna. Line of sight transmission is used for medium-distance radio transmission, such as cell phones, cordless phones, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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, switches, nodes, access points, links, etc. Most simulators use discrete event simulation in which the modeling of systems in which state variables change at discrete points in time. The behavior of the network and the various applications and services it supports can then be observed in a test lab; various attributes of the environment can also be modified in a controlled manner to assess how the network/protocols would behave under different conditions. Network simulator A network simulator is a software program that can predict the performance of a computer network or a wireless communication network. Since communication networks have become tool complex for traditional analytical methods to provide an accurate understanding of system behav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
