scholarly journals Impact of Dynamic Path Loss Models in an Urban Obstacle Aware Ad Hoc Network Environment

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Kashif Amjad ◽  
Muhammad Ali ◽  
Sohail Jabbar ◽  
Majid Hussain ◽  
Seungmin Rho ◽  
...  

This study highlights the importance of the physical layer and its impact on network performance in Mobile Ad Hoc Networks (MANETs). This was demonstrated by simulating various MANET scenarios using Network Simulator-2 (NS-2) with enhanced capability by adding propagation loss models (e.g., modified Two-Ray Ground model, ITU Line of Sight and Nonline of Sight (ITU-LoS and NLoS) model into street canyons and combined path loss and shadowing model (C-Shadowing)). The simulation results were then compared with the original Two-Ray Ground (TRG) model already available intoNS-2. The scenario primarily simulated was that of a mobile environment using Random Way Point (RWP) mobility model with a variable number of obstacles in the simulation field (such as buildings, etc., causing variable attenuation) in order to analyze the extent of communication losses in various propagation loss models. Performance of the Ad Hoc On-demand Distance Vector (AODV) routing protocol was also analyzed in an ad hoc environment with 20 nodes.

2020 ◽  
Vol 17 (4A) ◽  
pp. 588-597
Author(s):  
Ala'eddin Masadeh ◽  
Haythem Bany Salameh ◽  
Ahmad Abu-El-Haija

This work investigates the problem of managing the transmission power and assigning channels for multi-channel single-radio Cognitive Radio Ad-Hoc Networks (CRAHNs). The considered network consists of M primary users and N secondary users, where the secondary users can use the licensed channels opportunistically when they are not utilized by the primary users. The secondary users have the capability of sensing the licensed channels and determine their occupation status. They are also able to control their transmission power such that the transmitted data can be received with high quality-of-service with the lowest possible transmission power, and minimum interference among the secondary users. This also contributes in increasing the frequency spatial reuse of the licensed channels by the secondary users, when the channels are unoccupied, which increases the network throughput. This work proposes a channel assignment algorithm aims at assigning the unoccupied licensed channels among secondary users efficiently, and a transmission power control aims at tuning the transmission power used by the secondary users to maximize the network throughput. The results show an enhancement achieved by the proposed protocol when it is integrated to the considered network, which is seen through increasing the network throughput and decreasing in the access delay. In this context, the Network Simulator 2 (NS2) was used to verify our proposed protocol, which indicates a significant enhancement in network performance


2019 ◽  
Vol 63 (2) ◽  
pp. 203-219 ◽  
Author(s):  
Mani Zarei

Abstract Vehicular ad hoc networks (VANETs) have emerged as an appropriate class of information propagation technology promising to link us even while moving at high speeds. In VANETs, a piece of information propagates through consecutive connections. In the most previous vehicular connectivity analysis, the provided probability density function of intervehicle distance throughout the wide variety of steady-state traffic flow conditions is surprisingly invariant. But, using a constant assumption, generates approximate communication results, prevents us from improving the performance of the current solutions and impedes designing the new applications on VANETs. Hence, in this paper, a mesoscopic vehicular mobility model in a multilane highway with a steady-state traffic flow condition is adopted. To model a traffic-centric distribution for the spatial per-hop progress and the expected spatial per-hop progress, different intervehicle distance distributions are utilized. Moreover, the expected number of hops, distribution of the number of successful multihop forwarding, the expected time delay and the expected connectivity distance are mathematically investigated. Finally, to model the distribution of the connectivity distances, a set of simplistic closed-form traffic-centric equations is proposed. The accuracy of the proposed model is confirmed using an event-based network simulator as well as a road traffic simulator.


2021 ◽  
Vol 13 (7) ◽  
pp. 169
Author(s):  
Rajeshwari Chiluveru ◽  
Nishu Gupta ◽  
Ariel Soares Teles

Reliability and security when distributing safety messages among vehicles in an extremely mobile environment are prominent issues in Vehicular Ad-Hoc Networks (VANETs). In VANET, data transfer becomes challenging because of inherent features such as excessive speed, geographically constrained topologies, unsteady communication links, diversity in the capacity of the channel, etc. A major challenge in the multi-hop framework is maintaining and building a path under such a rigid environment. With VANET, potency in the traffic safety applications has performed well because of the proper design of medium access control (MAC) protocols. In this article, a protocol is proposed pertaining to the distribution of safety messages named mobility-aware multi-hop clustering-based MAC (MAMC-MAC) to accomplish minimum communication overhead, high reliability, and delivery of safety messages in real-time environments. MAMC-MAC has the ability to establish clustering-based multi-hop sequence using the time-division multiple access (TDMA) technique. The protocol was specially developed for highway outlines to achieve network enhancement and efficient channel usage and guarantees integrity among the vehicles. The performance of the proposed protocol is evaluated using Network Simulator (NS-2), and it demonstrates its superiority over various standard protocols in terms of a number of quality-of-service (QoS)-based parameters. The criteria to select and assess these parameters are their sensitivity and importance to the safety-based applications they provide.


2020 ◽  
Vol 8 (6) ◽  
pp. 4301-4310

One of the crucial and utilized simulator for mobile ad hoc network is the NS3 (Network Simulator). NS3 executes simulation scenarios and produces data regarding which flow monitor (flowMon) files are counted one of the important used format for estimating the research proposal. This article will introduce a novel framework to facilitate the simulation process in mobile ad hoc networks (MANETs). Generally speaking, when network researchers need to evaluate the experiments, there is generally the necessity to estimate the different models advantages by computing a set of QoS metrics to understand the network performance impact in such scenario. Network simulators, and NS3 specifically, need important program writing from the researcher to consolidate simulation results. This article states a contribution for NS3 composed of a new Framework that tends to make it less complicated to obtain and plot various QoS network performance metrics. This framework generates and runs simulations using common simulation parameters, such as velocity, mobility models, and number of nodes automatically. It also contains permits to parse through the generated flow that contain several essential metrics a researcher may need in order to analyze the simulation, such as end-to-end delay, lost packet, and throughput.


2020 ◽  
Vol 32 (2) ◽  
pp. 255-268
Author(s):  
Marija Malnar ◽  
Nenad Jevtić

During the last decade, the number of vehicles on roads has been rapidly growing. Therefore, the demands for communication on the move are also increasing and the attention from many researchers is focused on the Vehicular Ad hoc NETworks (VANETs) because of their importance for Intelligent Transportation Systems (ITSs). Due to the complexity and cost of practical evaluation of VANETs, the researchers often rely on network simulation in order to evaluate their work. In this paper, we have developed a Network Simulator 3 (NS-3) based framework for VANETs that provides network performance analysis based on the key performance indicators such as throughput, packet loss ratio, overhead, end-to-end delay, jitter, etc. Since VANETs are highly dynamic networks, many researchers have proposed different routing protocols in order to improve the network performance. In this paper we have compared several topology-based routing protocols, and proposed utilization of the commonly used Expected Transmission Count (ETX) metric to improve VANET performance.


Electronics ◽  
2021 ◽  
Vol 10 (14) ◽  
pp. 1635
Author(s):  
Neeraj Chugh ◽  
Geetam Singh Tomar ◽  
Robin Singh Bhadoria ◽  
Neetesh Saxena

To sustain the security services in a Mobile Ad Hoc Networks (MANET), applications in terms of confidentially, authentication, integrity, authorization, key management, and abnormal behavior detection/anomaly detection are significant. The implementation of a sophisticated security mechanism requires a large number of network resources that degrade network performance. In addition, routing protocols designed for MANETs should be energy efficient in order to maximize network performance. In line with this view, this work proposes a new hybrid method called the data-driven zone-based routing protocol (DD-ZRP) for resource-constrained MANETs that incorporate anomaly detection schemes for security and energy awareness using Network Simulator 3. Most of the existing schemes use constant threshold values, which leads to false positive issues in the network. DD-ZRP uses a dynamic threshold to detect anomalies in MANETs. The simulation results show an improved detection ratio and performance for DD-ZRP over existing schemes; the method is substantially better than the prevailing protocols with respect to anomaly detection for security enhancement, energy efficiency, and optimization of available resources.


2018 ◽  
Vol 7 (3.16) ◽  
pp. 76
Author(s):  
Deepak . ◽  
Rajkumar .

Vehicular ad hoc networks is an emerging area for researchers to provide intelligent transportation system to the society. It is due to the wide area of applications of VANETs interest is developed among the people from different countries to be a part of it. Therefore many projects had been started and also presently working to implement VANETs in real world scenario. The main challenge in its implementation is to provide a secure mechanism against the various attacks and threats that have the capability to bring the network performance significantly down. In this paper to overcome different types of authentication based attacks in VANETs an ECDSA based secure routing protocol SE-AODV is proposed with security features incorporated in already existing AODV routing protocol. The performance of SE-AODV is evaluated and compared with original AODV and AODV with black hole attack (BH-AODV). The SE-AODV shows better performance with the parameters used for comparison with the variation in vehicle density, speed of vehicles and simulation time. 


Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2764 ◽  
Author(s):  
Huanhuan Yang ◽  
Zongpu Jia ◽  
Guojun Xie

As an auxiliary facility, roadside units (RSUs) can well improve the shortcomings incurred by ad hoc networks and promote network performance in a vehicular ad hoc network (VANET). However, deploying a large number of RSUs will lead to high installation and maintenance costs. Therefore, trying to find the best locations is a key issue when deploying RSUs with the set delay and budget. In this paper, we study the delay-bounded and cost-limited RSU deployment (DBCL) problem in urban VANET. We prove it is non-deterministic polynomial-time hard (NP-hard), and a binary differential evolution scheme is proposed to maximize the number of roads covered by deploying RSUs. Opposite-based learning is introduced to initialize the first generation, and a binary differential mutation operator is designed to obtain binary coding. A random variable is added to the traditional crossover operator to increase population diversity. Also, a greedy-based individual reparation and promotion algorithm is adopted to repair infeasible solutions violating given constraints, and to gain optimal feasible solutions with the compromise of given limits. Moreover, after selection, a solution promotion algorithm is executed to promote the best solution found in generation. Simulation is performed on analog trajectories sets, and results show that our proposed algorithm has a higher road coverage ratio and lower packet loss compared with other schemes.


2018 ◽  
Vol 14 (11) ◽  
pp. 155014771881505 ◽  
Author(s):  
Ishtiaq Wahid ◽  
Ata Ul Aziz Ikram ◽  
Masood Ahmad ◽  
Fasee Ullah

With resource constraint’s distributed architecture and dynamic topology, network issues such as congestion, latency, power awareness, mobility, and other quality of service issues need to be addressed by optimizing the routing protocols. As a result, a number of routing protocols have been proposed. Routing protocols have trade-offs in performance parameters and their performance varies with the underlying mobility model. For designing an improved vehicular ad hoc network, three components of the network are to be focused: routing protocols, mobility models, and performance metrics. This article describes the relationship of these components, trade-offs in performance, and proposes a supervisory protocol, which monitors the scenario and detects the realistic mobility model through analysis of the microscopic features of the mobility model. An analytical model is used to determine the best protocol for a particular mobility model. The supervisory protocol then selects the best routing protocol for the mobility model of the current operational environment. For this, EstiNet 8.1 Simulator is used to validate the proposed scheme and compare its performance with existing schemes. Simulation results of the proposed scheme show the consistency in the performance of network throughout its operation.


Sign in / Sign up

Export Citation Format

Share Document