NS2 Software Research Articles

Parking Space Reservation based on VANETs

With the rapid increase of private vehicles, finding an available parking space in urban cities is indeed stressful, time-consuming. Reservation mechanism is a good method for solving this problem. In this paper, we present a parking space reservation method based on VANETs. Firstly, we set a Road Side Unit (RSU) at every important intersection to collect traffic information which utilizes the proposed timeprediction model to predict the travel time. Then, a parking space reservation mechanism is proposed according to a dynamic path selection based on real-time traffic information. At last, extensive evaluations using the software VanetMobisim and NS2 have been performed, and we can see the method we proposed make good travel time prediction which is useful and meaningful in parking spaces reservation for drivers and facility managers.

Load-Balancing Enhancement by a Mobile Data Collector in Wireless Sensor Networks

Abstract Decrease in the time interval between the first node death and the last node death, due to the completion of their energy supply, is the main goal of load-balancing methods in Wireless Sensor Networks (WSN). This paper proposes a Load-Balancing Enhancement (LBE) method, in WSN. LBE method uses a mobile data collector to data gathering from sensor nodes. The mobile data collector can directly communicate with the base station. Indeed, the mobile data collector acts as an interface between sensor nodes and the base station. LBE method divides WSN to four logical partitions. Then, LBE method directs the mobile data collector to the center of each logical partition of the network with considering the density and the mean residual energy of the desired partition, i.e., the more the partition density and the mean residual energy, the more the obtaining chance of the desired partition. Simulation results that have been implemented with NS-2 software show LBE method achieves load-balancing in energy consumption for all logical partitions. LBE method also balances logical partitions density and it increases the network coverage efficiency.

Optimization based Routing Algorithms

A new agent-based routing algorithm using optimization techniques is discussed in this paper. The different optimization techniques are Ant, Bee, Ant Bee, Ant GA, Ant PSO, GA, PSO, Pillar, Simulated Annealing, Ant Pillar, Bee Pillar, GA PSO, GA Pillar, GA-SA,PSO Pillar, PSO SA, Bee PSO, Bee GA, Bee SA are the combinations used in the packet delivery between the networks. The routing is a process of carrying the data from source to destination in the network. The outputs of these algorithms are determined by the simulation time and throughput. The experiments are implemented with the NS2 software platform, which is based on the basics of C, C++, and TCL Scripting Language. The results of the algorithm showed that the GA-PSO is much better than the other algorithms in the packet delivery between the networks.

The Square Root Multipliers Algorithm for Discrete Capacity and Buffer Assignment problems in Elastic Traffic Networks

This paper discusses a novel approach for the dimensioning of packet networks, under the constraints of end-to-end Quality-of-Service (QoS) requirements. The network modeling also considers the dynamic behavior of today's networks traffic. In particular, the proposed approach considers multilink networks where discrete capacities are the decision variables. This Discrete Capacity Assignment (DCA) problem can be classified as a constrained combinatorial optimization problem and therefore it is NP-complete. In order to solve the problem, we propose the Square Root Multipliers Algorithm (SRMA) followed by a Randomized Rounding (RR) method. We also enforce loss probability constraints by properly choosing buffer sizes, therefore facing the Buffer Assignment (BA) problem. To evaluate the performance of our approach, SRMA/RR results are compared with the optimal solutions found by an exhaustive search (ES) procedure. Analytical results for a variety of problem instances are reported, and a verification is performed based on simulations conducted with the software NS-2. The results suggest that the proposed approach provides a quite efficient method to obtain near-optimal solutions with small computational effort.

Geographic routing algorithm based on anchor nodes in vehicular network

Vehicular network has the following characteristics such as nodes moving fast,topology changing rapidly. The direct use of Global Positioning System(GPS) devices causes large positioning error and low routing connectivity rate.Therefore,the packet delivery rate of the existing location-based routing algorithm is not high enough to provide reliable routing. A geographic routing algorithm based on anchor node in vehicle networks named Geographic Routing based on Anchor Nodes(GRAN) was proposed. Using street lamps as anchor nodes,a vehicle could locate itself through the anchor nodes.Combined with the road gateway and the central data,GRAN established a hierarchical routing structure,thus removing the steps of route discovery and the whole network broadcast. Thus,the routing overhead was reduced and the routing efficiency and the packet delivery rate were improved. By using the NS-2 software and selecting a realistic urban scene,a simulation was conducted on Greedy Perimeter Stateless Routing(GPSR),Graphic Source Routing(GSR) and GRAN. The experimental results show that GRAN can provide a lower average delay,higher packet delivery ratio and throughput at a lower load,compared with several typical location-based routing protocols.

A Dynamic and Energy-Efficient Clustering Algorithm in Large-Scale Mobile Sensor Networks

Random mobility and energy constraint are two main factors affecting system performance in mobile sensor networks, which cause many difficulties to system design. It is necessary to develop high-efficiency algorithms and protocols for mobile sensor networks to adapt to dynamic network environment and energy limitation. In this paper, a new clustering algorithm based on residual energy difference ratio is presented to improve system performance. Firstly, it is an energy-efficient algorithm. The residual energy of sensor nodes and average residual energy of system are considered in the residual energy difference ratio, which effectively avoid the nodes with low residual energy being selected as cluster heads. An energy-optimal scheme is used in cluster formation phase to minimize energy consumption. Secondly, it is a dynamic algorithm. The system dynamically clusters the sensor nodes according to the data transmission delays. It makes the whole system adapt to the random mobility of sensor nodes. The NS2 software is used to simulate the new clustering algorithm. The simulation experiments can verify the validity of the proposed theory.

The Research and Design of Data Aggregation Technique in WSNs

Data aggregation technique is widely used for its advantages in reducing data throughput and avoiding collision. Meanwhile, it also introduces some additional security concerns. So it is meaningful to research secure data aggregation. We firstly introduced the related concepts and key technologies of WSNs secure data aggregation. Then an effective data aggregation algorithm (EDAA) is proposed after the SMART algorithm is analyzed. The algorithm is simulated in NS2 software, and the result shows that the data aggregation algorithm EDAA can effectively reduce the transmission costs and the energy consumption of nodes

Faulty Sensor Node Detection Using Round Trip Time and Discrete Paths in WSNs

Wireless sensor networks (WSNs) with efficient and accurate design to increase the quality of service (QoS) have become a hot area of research. Implementing the efficient and accurate WSNs requires deployment of the large numbers of portable sensor nodes in the field. The quality of service of such networks is affected by lifetime and failure of sensor node. In order to improve the quality of service, the data from faulty sensor nodes has to be ignored or discarded in the decision-making process. Hence, detection of faulty sensor node is of prime importance. In the proposed method, discrete round trip paths (RTPs) are compared on the basis of round trip delay (RTD) time to detect the faulty sensor node. RTD protocol is implemented in NS2 software. WSNs with circular topology are simulated to determine the RTD time of discrete RTPs. Scalability of the proposed method is verified by simulating the WSNs with various sensor nodes.

A Routing Algorithm Based on Dynamic Forecast of Vehicle Speed and Position in VANET

Considering city road environment as the background, by researching GPSR greedy algorithm and the movement characteristics of vehicle nodes in VANET, this paper proposes the concept of circle changing trends angle in vehicle speed fluctuation curve and the movement domain and designs an SWF routing algorithm based on the vehicle speed point forecasted and the changing trends time computation. Simulation experiments are carried out through using a combination of NS-2 and VanetMobiSim software. Compared with the performance of the SWF-GPSR protocol with general GPSR, 2-hop C-GEDIR, and the GRA and AODV protocols, we find that the SWF algorithm has a certain degree of improvement in routing hops, the packet delivery ratio, delay performance, and link stability.

A Comparative Study of AODV and DSDV Routing Protocol of the Vehicle Ad Hoc Network Based on NS2

This document analyzes the wireless ad hoc networks used in vehicle communication. Using the NS2 software, the typical ad hoc on-demand distance vector routing (AODV) and destination-sequenced distance-vector (DSDV) routing protocol are simulated respectively with 25 mobile nodes and 11 mobile nodes. By reasoning on the simulation data, many performance indicators including the routing protocol throughput, jitter, packet loss rate and end-to-end delay performance are compared and analyzed. Final we have come to an important conclusion that AODV is better than DSDV protocol on a number of performance indicators.

A Framework for Secure and Efficient Data Acquisition in Vehicular Ad Hoc Networks

Intervehicular communication lies at the core of a number of industry and academic research initiatives that aim at enhancing the safety and efficiency of transportation systems. Vehicular ad hoc networks (VANETs) enable vehicles to communicate with each other and with roadside units (RSUs). Service-oriented vehicular networks are special types of VANETs that support diverse infrastructure-based commercial services, including Internet access, real-time traffic management, video streaming, and content distribution. Many forms of attacks against service-oriented VANETs that attempt to threaten their security have emerged. The success of data acquisition and delivery systems depends on their ability to defend against the different types of security and privacy attacks that exist in service-oriented VANETs. This paper introduces a system that takes advantage of the RSUs that are connected to the Internet and that provide various types of information to VANET users. We provide a suite of novel security and privacy mechanisms in our proposed system and evaluate its performance using the ns2 software. We show, by comparing its results to those of another system, its feasibility and efficiency.

Finding a STAR in a Vehicular Cloud

The strong capabilities that exist in a Vehicular Ad hoc Network (VANET) has given birth to the concept of Vehicular Clouds, in which cloud computing services are hosted by vehicles that have sufficient resources to act as mobile cloud servers. In this paper, we design a system that enables vehicles in a VANET to search for mobile cloud servers that are moving nearby and discover their services and resources. The system depends on RSUs that act as cloud directories with which mobile cloud servers register. The RSUs share their registration data to enable vehicles to discover and consume the services of mobile cloud servers within a certain area. We evaluated the proposed system using the ns2 software and demonstrated through comparing the results to another mechanism the feasibility and efficiency of our system in terms of service discovery and service consuming delays and packet success ratio.

An Energy-Efficient Cluster Head and Router Selecting Protocol for Wireless Sensor Networks

Wireless sensor networks (WSNs) based on ZigBee technology are currently popular low-energy, low-cost, short-distance communication technologies that can be applied in many areas, such as industry, environment, agriculture, etc. Energy efficiency is one of the most important research points for WSNs. In this paper, we analyze the existing WSNs protocols, especially LEACH, and propose an energy-efficient cluster head and router selecting protocol (EECRS). EECRS combines both cluster-based and energy-threshold routing protocols to balance the energy consumption of the sensor nodes in the whole network in order to extend the network lifetime. And through the simulation via NS2 software, it is shown that EECRS improves the network performance, network lifetime and data received per energy mount consumption, compared with LEACH protocol.

Simulation Research on Networked Control System Based on NS-2

A key issue in NCS is network transmission. In the research of network control, in some special fields, the system performance could be evaluated based on the real-time character of data transmission in the LAN, but the result gotten in this kind of method isn’t representative. In this paper, a simulation model is firstly established via the NS-2 software under research of network transmission, and then the interval segmentation time-delay and the constant time-delay compensation methods of network control are investigated under this environment. Simulation result validates the effectiveness of the model.

A Hybrid System for Detecting Misbehaving Nodes in Ad Hoc Networks

In this paper we express a new intrusion detection system based on counters and a cache memory to detect malicious nodes and selfish nodes in ad hoc network. Network survivability, networks performance and network security are important issues in mentioned networks. The presented work enhances the mentioned factors because it doesn't need heavy computation and also its speed and accuracy in detecting suspicious nodes are great. We simulated our methods by NS2 software. The simulation results show that the proposed method has significant performance.

Detection and avoidance of node misbehavior in MANET based on CLAODV

This paper depicts a model which not only evaluates the node's reputation, but also avoids the malicious node in the forwarding path. The simulation is performed by using the NS2 software. This model uses the IEEE 802.11 protocol with RTS, CTS, DATA and ACK signalling at the MAC layer. The paper models packet forwarding, passive misbehavior, active misbehavior and avoidance of malicious nodes in the route. The model also takes into account the blocking caused by the hidden node problem in wireless networks. The results achieved are both graphical as well as in the form of a network animation. Curves such as throughput and jitter are plotted to analyse the performance of the MANET.

Energy-efficient multipath routing in wireless sensor network considering wireless interference

Due to the energy and resource constraints of a wireless sensor node in a wireless sensor network (WSN), design of energy-efficient multipath routing protocols is a crucial concern for WSN applications. To provide high-quality monitoring information, many WSN applications require high-rate data transmission. Multipath routing protocols are often used to increase the network transmission rate and throughput. Although large-scale WSN can be supported by high bandwidth backbone network, the WSN remains the bottleneck due to resource constraints of wireless sensors and the effects of wireless interference. In this paper, we propose a multipath energy-efficient routing protocol for WSN that considers wireless interference. In the proposed routing protocol, nodes in the interference zone of the discovered path are marked and not allowed to take part in the subsequent routing process. In this way, the quality of wireless communication is improved because the effects of wireless interference can be reduced as much as possible. The network load is distributed on multiple paths instead of concentrating on only one path, and node energy cost is more balanced for the entire wireless network. The routing protocol is simulated in NS2 software. Simulation result shows that the proposed routing protocol achieves lower energy cost and longer network lifetime than that in the literature.

Research and Construction on Simulation Traffic Environment with Inter-Car Communication

In this paper a specific construction method based on the NS-2 software environment was studied to simulate the inter-car communication and constitutes. And the implementation methods of inter-car communication were described. The simulation traffic environment what we have described have good use to the research of relate technologies in the intelligent transportation systems such as inter-car etc., and have a important meaning to the simulation experiment of inter-car and algorithm.

Sensor Position Determination with Flying Anchors in Three-Dimensional Wireless Sensor Networks

This paper presents a range-free position determination (localization) mechanism for sensors in a three-dimensional wireless sensor network based on the use of flying anchors. In the scheme, each anchor is equipped with a Global Positioning System (GPS) receiver and broadcasts its location information as it flies through the sensing space. Each sensor node in the sensing area then estimates its own location by applying basic geometry principles to the location information it receives from the flying anchors. The scheme eliminates the requirement for specific positioning hardware, avoids the need for any interaction between the individual sensor nodes, and is independent of network densities and topologies. The performance of the localization scheme is evaluated in a series of simulations performed using ns-2 software and is compared to that of the Centroid and Constraint range-free mechanisms. The simulation results demonstrate that the localization scheme outperforms both Centroid and Constraint in terms of a higher location accuracy, a reduced localization time, and a lower beacon overhead. In addition, the localization scheme is implemented on the Tmote Sky for validating the feasibility in the real environment.

COACS: A Cooperative and Adaptive Caching System for MANETs

This paper introduces a cooperation-based database caching system for Mobile Ad Hoc Networks (MANETs). The heart of the system is the nodes that cache submitted queries. The queries are used as indices to data cached in nodes that previously requested them. We discuss how the system is formed and how requested data is found if cached, or retrieved from the external database and then cached. Analysis is performed and expressions are derived for the different parameters, including upper and lower bounds for the number of query caching nodes as well as the average load they experience, generated network traffic, node bandwidth consumption, and other performance-related measures. Simulations with the ns-2 software were used to study the performance of the system in terms of average delay and hit ratio, and to compare it with the performance of two other caching schemes for MANETs, namely CachePath and CacheData. The results demonstrate the effectiveness of the proposed system in terms of achieved hit ratio and low delay.