This document provides a review of approaches for enhancing the performance of vehicular ad hoc networks (VANETs) using CSMA-MACA. It begins with an introduction to VANETs and discusses some of their key properties including high dynamic topology, frequent disconnections, and the hidden terminal problem. The document then reviews related work on hybrid approaches combining CSMA and MACA for routing in VANETs. Finally, it provides details on commonly used routing protocols like AODV and discusses how accounting for obstacles in simulations can improve safety performance evaluations of VANET applications.
Analysis of a framework implementation of the transceiver performances for in...IJECEIAES
The greatest advantages of optical fibers are the possibility of extending data rate transmission and propagation distances. Being a multicarrier technique, the orthogonal frequency division multiplexing (OFDM) can be applicable in hybrid optical-wireless systems design owing to its best spectral efficiency for the interferences of radio frequency (RF) and minor multipath distortion. An optical OFDM-RoF-based wireless local area network (W-LAN) system has been studied and evaluated in this work. The outline for integrating an optical technology and wireless in a single system was provided with the existence of OFDM-RoF technology and the microstrip patch antenna; these were applied in the Optisystem communication tool. The design of the proposed OFDM-RoF system is aimed at supporting mm-wave services and multi-standard operations. The proposed system can operate on different RF bands using different modulation schemes like 4.16 and 64QAM that may be associated to OFDM and multidata rates up to 5 Gbps. The results demonstrate the robustness of the integrated optical wireless link in propagating OFDM-RoF-based WLAN signals across optical fibers.
Mobile Ad hoc Networks (MANETs) have drawn considerable attentions of the researchers for the last few years. MANETs, consisting of mobile nodes, are self-organizing and self-configuring and hence can be deployed without any infrastructure support. MANETs also have some limitations including short-life, unreliability, scalability, latency, high interference, and limited resources. In order to overcome these limitations many innovations and researches have been done in this field. Incorporating smart antenn system with the mobile nodes is one of them. It has been shown in the literatures that smart antenna can improve network capacity, increase network lifetime, reduce delay, and improve scalability by using directional radiation pattern. But, there are some unsolvedissues too. Smart antenna requires a large
number of antenna elements that a resource constraint mobile node can hardly handle. Hence, one major
design issue is to achieve a desired radiation pattern by using minimum number of antenna elements. Another important issue is the arrangement of antenna elements. Antenna elements can be arranged in linear, planar, and circular manners. In this paper we have addressed these issues. We have proposed a window based smart antenna design for MANETs. Our target is to improve the routing performance of
MANETs. We have shown that by using appropriate window function a desired radiation pattern can be achieved with a minimum number of antenna elements.
Establishment Network by Using FSO Link Based on MD Code for Hybrid SCM-SAC-O...IJECEIAES
Since the wireless systems are working under nature environments and influenced by turbulence, weather in Iraq that leads to extended amount of fading signal, dissipation or attenuation. Basic “hybrid Subcarrier Multiplying Spectral Amplitude Coding (SCM-SAC) of Optical Code Division Multiple Access (OCDMA)" indoor or outdoor optical system depends on generally “Multi-Diagonal (MD)" security code by using optical space known as “Free Space Optic (FSO)" that was proposed in this work. It is found that the mention hybrid wireless systems can be used in operating mesh networks. The main proposed idea of hybrid optical technique was analyzed and simulated by normally taking into simulation account that the directly effecting by rain and haze attenuations. In addition, there are mention and description for atmospheric effects, FSO mesh network, modulation scheme, simulation, and the data security. From simulation results, the hybrid system using MD code produces reduced “bit-error rate (BER)" at heavy storm rain to distance or range of 500 m and at drizzle rain up to 2500 m range. And also investigates the performance of using the proposed system with radio over fiber (RoF) for UWB signals through indoor propagation in building applications of wireless channel.
BER PERFORMANCE ANALYSIS FOR WIMAX PHY LAYER UNDER DIFFERENT CHANNEL CONDITIONSijistjournal
This paper gives an introduction on the IEEE 802.16 standard – WIMAX or Worldwide Interoperability for
Microwave Access. The different parts give details on the architectural specifications of WiMAX networks
and also on the working principle of WiMAX networks including its services provided. It also provides brief
descriptions on its salient features of this technology and how it benefits the networking industry. A brief
outline of the basic building blocks or equipment of WiMAX architecture is also provided. This paper also
evaluates the simulation performance of IEEE 802.16 OFDM PHY layer. The Stanford University Interim
(SUI) channel model under varying parameters is selected for the wireless channel in the simulation. The
performance measurements and analysis was done in simulation developed in MATLAB.
Analysis of a framework implementation of the transceiver performances for in...IJECEIAES
The greatest advantages of optical fibers are the possibility of extending data rate transmission and propagation distances. Being a multicarrier technique, the orthogonal frequency division multiplexing (OFDM) can be applicable in hybrid optical-wireless systems design owing to its best spectral efficiency for the interferences of radio frequency (RF) and minor multipath distortion. An optical OFDM-RoF-based wireless local area network (W-LAN) system has been studied and evaluated in this work. The outline for integrating an optical technology and wireless in a single system was provided with the existence of OFDM-RoF technology and the microstrip patch antenna; these were applied in the Optisystem communication tool. The design of the proposed OFDM-RoF system is aimed at supporting mm-wave services and multi-standard operations. The proposed system can operate on different RF bands using different modulation schemes like 4.16 and 64QAM that may be associated to OFDM and multidata rates up to 5 Gbps. The results demonstrate the robustness of the integrated optical wireless link in propagating OFDM-RoF-based WLAN signals across optical fibers.
Mobile Ad hoc Networks (MANETs) have drawn considerable attentions of the researchers for the last few years. MANETs, consisting of mobile nodes, are self-organizing and self-configuring and hence can be deployed without any infrastructure support. MANETs also have some limitations including short-life, unreliability, scalability, latency, high interference, and limited resources. In order to overcome these limitations many innovations and researches have been done in this field. Incorporating smart antenn system with the mobile nodes is one of them. It has been shown in the literatures that smart antenna can improve network capacity, increase network lifetime, reduce delay, and improve scalability by using directional radiation pattern. But, there are some unsolvedissues too. Smart antenna requires a large
number of antenna elements that a resource constraint mobile node can hardly handle. Hence, one major
design issue is to achieve a desired radiation pattern by using minimum number of antenna elements. Another important issue is the arrangement of antenna elements. Antenna elements can be arranged in linear, planar, and circular manners. In this paper we have addressed these issues. We have proposed a window based smart antenna design for MANETs. Our target is to improve the routing performance of
MANETs. We have shown that by using appropriate window function a desired radiation pattern can be achieved with a minimum number of antenna elements.
Establishment Network by Using FSO Link Based on MD Code for Hybrid SCM-SAC-O...IJECEIAES
Since the wireless systems are working under nature environments and influenced by turbulence, weather in Iraq that leads to extended amount of fading signal, dissipation or attenuation. Basic “hybrid Subcarrier Multiplying Spectral Amplitude Coding (SCM-SAC) of Optical Code Division Multiple Access (OCDMA)" indoor or outdoor optical system depends on generally “Multi-Diagonal (MD)" security code by using optical space known as “Free Space Optic (FSO)" that was proposed in this work. It is found that the mention hybrid wireless systems can be used in operating mesh networks. The main proposed idea of hybrid optical technique was analyzed and simulated by normally taking into simulation account that the directly effecting by rain and haze attenuations. In addition, there are mention and description for atmospheric effects, FSO mesh network, modulation scheme, simulation, and the data security. From simulation results, the hybrid system using MD code produces reduced “bit-error rate (BER)" at heavy storm rain to distance or range of 500 m and at drizzle rain up to 2500 m range. And also investigates the performance of using the proposed system with radio over fiber (RoF) for UWB signals through indoor propagation in building applications of wireless channel.
BER PERFORMANCE ANALYSIS FOR WIMAX PHY LAYER UNDER DIFFERENT CHANNEL CONDITIONSijistjournal
This paper gives an introduction on the IEEE 802.16 standard – WIMAX or Worldwide Interoperability for
Microwave Access. The different parts give details on the architectural specifications of WiMAX networks
and also on the working principle of WiMAX networks including its services provided. It also provides brief
descriptions on its salient features of this technology and how it benefits the networking industry. A brief
outline of the basic building blocks or equipment of WiMAX architecture is also provided. This paper also
evaluates the simulation performance of IEEE 802.16 OFDM PHY layer. The Stanford University Interim
(SUI) channel model under varying parameters is selected for the wireless channel in the simulation. The
performance measurements and analysis was done in simulation developed in MATLAB.
Impact of Next Generation Cognitive Radio Network on the Wireless Green Eco s...ijeei-iaes
Land mobile communication is burdened with typical propagation constraints due to the channel characteristics in radio systems.Also,the propagation characteristics vary form place to place and also as the mobile unit moves,from time to time.Hence,the tramsmission path between transmitter and receiver varies from simple direct LOS to the one which is severely obstructed by buildings, foliage and terrain. Multipath propagation and shadow fading effects affect the signal strength of an arbitrary Transmitter-Receiver due to the rapid fluctuations in the phase and amplitude of signal which also determines the average power over an area of tens or hundreds of meters. Shadowing introduces additional fluctuations, so the received local mean power varies around the area –mean. The present paper deals with the performance analysis of impact of next generation wireless cognitive radio network on wireless green eco system through signal and interference level based k coverage probability under the shadow fading effects.
Cognitive Radio (CR) is an adaptive, intelligent radio and network technology that can automatically detect available channels in a wireless spectrum and change transmission parameters enabling more communications to run concurrently and also improve radio operating behavior.
CR technology is based on the fact that the licensed systems (also named primary systems PS) are not always using their spectrum bands; CR brings new radio types—cognitive radios—that should firstly, identify the existing spectrum holes, and secondly, utilize them according to an access
Radio over fiber system based on a hybrid link for next generation of optical...IJECEIAES
Radio over fiber technology will play an important role in solving problems facing wireless technology. Envisaging a global village, people could transmit and receive “anytime, anywhere, and anything”. In addition, the explosive growth in internet applications such as the World Wide Web, demonstrates the tremendous increase in bandwidth and low power that the coming world of multimedia interactive applications will require from future networks. ROF technology uses multicarrier modulation like orthogonal frequency division multiplexing (OFDM), which provides an opportunity of having an increased in bandwidth together with an affordable cost and this idea has recently become a suitable topic for many research works. On the other hand, SAC-OCDMA (Spectral Amplitude Coding Optical Code Division Multiple Access) technique is able to enhance the data rate of system and increase the number of user. In this paper we introduce a ROF link using a hybrid OFDM/SAC-OCDMA technique.
Enhanced direct sequence spread spectrum (eDSSS) method tomitigate SINR misma...IJECEIAES
Demand of data usage and increase of subscribers in Long Term Evolution (LTE) has urged Third Group Partnership Project (3GPP) to find a solution of traffic data growth. In Release 12, the 3GPP introduced Wi-Fi as an alternative to ease the heavy traffic at the LTE base station in dense areas. In contrary with the traffic offloading, Wi-Fi users suffer the worst network degradation because of co-channel interference at frequency 2.4GHz due to collided with LTE band 40. Interference management in LTE-Wi-Fi integrated network is crucial as it affect user’s experiences and services. In this paper, we enhanced a method which is Direct Sequence Spread Spectrum (DSSS) to improve user’s performance in LTE-Wi-Fi network. The DSSS has advantages such as more robust and ability to expand to higher data rates. We introduce a new coefficient called as chip rate coefficient (α) to investigate Signal -to-Interference-Noise Ratio (SINR) expression for User Equipments (UEs) in LTE-Wi-Fi networks. The simulation results discovered that proposed α with value of 0.2 gave the optimum improvement of SINR for LTE and Wi-Fi users. By modifying the SINR expression of the standard DSSS, SINR values at MUE and WUE show better improvement with 4.69% and 17.94%, respectively.
Comprehensive investigation of coherent optical OFDM-RoF employing 16QAM exte...IJECEIAES
Given the growing need for long haul transmission that requires a high rate of data, the orthogonal frequency division multiplexing scheme (OFDM), is regarded as a technique with high potentials for high-capacity optical networks. OFDM transmits over both optical and wireless channels, with the data distributed over a huge amount of the subcarrier, and the data is distributed over a huge number of subcarriers. OFDM achieves RF signal for a long-haul transmitting by utilizing Radio over Fiber (RoF) system, which is known to produce higher orthogonality of the OFDM modulated signal designed for the wireless network. RoF systems comprise of heterogeneous networks designed through the use of wireless and optical links. The aim of this paper is to carry out an investigation of the performance of the external modulation in RoF links, while analyzing the shortcomings caused by the various elements of the optical system. The Mach–Zehnder modulator (MZM) can be applied in external modulation, and exhibits a more robust performance when implemented with the OFDM modulation technique.
Techniques for Improving BER and SNR in MIMO Antenna for Optimum PerformanceIJMTST Journal
The use of multiple antennas for diversity, including MIMO (Multiple Input Multiple Output) is one of the most promising wireless technologies for broadband communication applications. This antenna system is a vital study in today’s wireless communication system especially when the signal propagates through some corrupted environments. In our paper new techniques of improving bit error ratio and signal to noise ratio are discussed. Inter symbol interference is a major limitation of wireless communications. It degrades the performance significantly if the delay spread is comparable or higher than the symbol duration. To remove ISI, equalization needs to be included at the receiver end. This paper discusses the merits of the MIMO system and the techniques used for improving BER performance and SNR. In MIMO wireless communication, an equalizer is used to recover a signal that suffers from Inter symbol Interference (ISI) and the BER characteristics is improved and a good SNR can be obtained. Different equalization techniques are discussed in this paper.
International Journal of Computational Engineering Research(IJCER) ijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
Analysis of Handoff techniques used for hybrid networks: cellular/WLAN IJORCS
Most real life networks are hybrid networks. A hybrid network combines the best features of two or more networks. In networking terminology, a hybrid network according to “Information Technology control and Audit” are reliable and versatile. They provide large numbers of connections and data transmission paths to users. These hybrid networks may be treated as network nodes for analysis purpose. The two radio access technologies (RATs) are considered with cellular/WLAN depending on whether it is voice/ data, video. For observing practical result, some setups are required in laboratory which includes interface from personal computer to mobile terminal and vice-versa. The network simulator (Ns-2) is used for analysis purpose. The results shows the parameters like energy good put, Bandwidth utilization, packet delivery ratio, energy good put and energy consumed are improved after using hybrid networks.
Millimeter Wave Mobile Broadband: Unleashing 3-300 GHz SpectrumFarooq Khan
This presentation from IEEE Wireless Communications & Networking Conference in 2011 started the 5G conversation and busted many of the myths about millimeter waves and their applicability to mobile wireless communications.
Femtocell is a small cellular base station,designe d for use in residential or enterprise. Connects to the service provider�s network via broa dband.Femtocell is one type of Indoor network which provide the wireless access within th e particular area. Femtocells ensure that carefully planned cellular networks which may conne ct anespecially of the citizens to the Internet and with one another. In this paper femtoc ells has such network which maintains the specialty of the data transfer through the network will femtocells prove more trouble than they are worth,femtocells just an exciting but Minimum stage of network evolution that will beimproved Wireless offloading,new backhaul regula tions and/or pricing,or other unforeseen technological developments? This paper overviews th e history of femtocells,demystifies their key aspects,and provides a preview of the next few years� acceleration towards small cell technology. This paper reports,we also position an d introduce the articles that headline this special issue.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Impact of Next Generation Cognitive Radio Network on the Wireless Green Eco s...ijeei-iaes
Land mobile communication is burdened with typical propagation constraints due to the channel characteristics in radio systems.Also,the propagation characteristics vary form place to place and also as the mobile unit moves,from time to time.Hence,the tramsmission path between transmitter and receiver varies from simple direct LOS to the one which is severely obstructed by buildings, foliage and terrain. Multipath propagation and shadow fading effects affect the signal strength of an arbitrary Transmitter-Receiver due to the rapid fluctuations in the phase and amplitude of signal which also determines the average power over an area of tens or hundreds of meters. Shadowing introduces additional fluctuations, so the received local mean power varies around the area –mean. The present paper deals with the performance analysis of impact of next generation wireless cognitive radio network on wireless green eco system through signal and interference level based k coverage probability under the shadow fading effects.
Cognitive Radio (CR) is an adaptive, intelligent radio and network technology that can automatically detect available channels in a wireless spectrum and change transmission parameters enabling more communications to run concurrently and also improve radio operating behavior.
CR technology is based on the fact that the licensed systems (also named primary systems PS) are not always using their spectrum bands; CR brings new radio types—cognitive radios—that should firstly, identify the existing spectrum holes, and secondly, utilize them according to an access
Radio over fiber system based on a hybrid link for next generation of optical...IJECEIAES
Radio over fiber technology will play an important role in solving problems facing wireless technology. Envisaging a global village, people could transmit and receive “anytime, anywhere, and anything”. In addition, the explosive growth in internet applications such as the World Wide Web, demonstrates the tremendous increase in bandwidth and low power that the coming world of multimedia interactive applications will require from future networks. ROF technology uses multicarrier modulation like orthogonal frequency division multiplexing (OFDM), which provides an opportunity of having an increased in bandwidth together with an affordable cost and this idea has recently become a suitable topic for many research works. On the other hand, SAC-OCDMA (Spectral Amplitude Coding Optical Code Division Multiple Access) technique is able to enhance the data rate of system and increase the number of user. In this paper we introduce a ROF link using a hybrid OFDM/SAC-OCDMA technique.
Enhanced direct sequence spread spectrum (eDSSS) method tomitigate SINR misma...IJECEIAES
Demand of data usage and increase of subscribers in Long Term Evolution (LTE) has urged Third Group Partnership Project (3GPP) to find a solution of traffic data growth. In Release 12, the 3GPP introduced Wi-Fi as an alternative to ease the heavy traffic at the LTE base station in dense areas. In contrary with the traffic offloading, Wi-Fi users suffer the worst network degradation because of co-channel interference at frequency 2.4GHz due to collided with LTE band 40. Interference management in LTE-Wi-Fi integrated network is crucial as it affect user’s experiences and services. In this paper, we enhanced a method which is Direct Sequence Spread Spectrum (DSSS) to improve user’s performance in LTE-Wi-Fi network. The DSSS has advantages such as more robust and ability to expand to higher data rates. We introduce a new coefficient called as chip rate coefficient (α) to investigate Signal -to-Interference-Noise Ratio (SINR) expression for User Equipments (UEs) in LTE-Wi-Fi networks. The simulation results discovered that proposed α with value of 0.2 gave the optimum improvement of SINR for LTE and Wi-Fi users. By modifying the SINR expression of the standard DSSS, SINR values at MUE and WUE show better improvement with 4.69% and 17.94%, respectively.
Comprehensive investigation of coherent optical OFDM-RoF employing 16QAM exte...IJECEIAES
Given the growing need for long haul transmission that requires a high rate of data, the orthogonal frequency division multiplexing scheme (OFDM), is regarded as a technique with high potentials for high-capacity optical networks. OFDM transmits over both optical and wireless channels, with the data distributed over a huge amount of the subcarrier, and the data is distributed over a huge number of subcarriers. OFDM achieves RF signal for a long-haul transmitting by utilizing Radio over Fiber (RoF) system, which is known to produce higher orthogonality of the OFDM modulated signal designed for the wireless network. RoF systems comprise of heterogeneous networks designed through the use of wireless and optical links. The aim of this paper is to carry out an investigation of the performance of the external modulation in RoF links, while analyzing the shortcomings caused by the various elements of the optical system. The Mach–Zehnder modulator (MZM) can be applied in external modulation, and exhibits a more robust performance when implemented with the OFDM modulation technique.
Techniques for Improving BER and SNR in MIMO Antenna for Optimum PerformanceIJMTST Journal
The use of multiple antennas for diversity, including MIMO (Multiple Input Multiple Output) is one of the most promising wireless technologies for broadband communication applications. This antenna system is a vital study in today’s wireless communication system especially when the signal propagates through some corrupted environments. In our paper new techniques of improving bit error ratio and signal to noise ratio are discussed. Inter symbol interference is a major limitation of wireless communications. It degrades the performance significantly if the delay spread is comparable or higher than the symbol duration. To remove ISI, equalization needs to be included at the receiver end. This paper discusses the merits of the MIMO system and the techniques used for improving BER performance and SNR. In MIMO wireless communication, an equalizer is used to recover a signal that suffers from Inter symbol Interference (ISI) and the BER characteristics is improved and a good SNR can be obtained. Different equalization techniques are discussed in this paper.
International Journal of Computational Engineering Research(IJCER) ijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
Analysis of Handoff techniques used for hybrid networks: cellular/WLAN IJORCS
Most real life networks are hybrid networks. A hybrid network combines the best features of two or more networks. In networking terminology, a hybrid network according to “Information Technology control and Audit” are reliable and versatile. They provide large numbers of connections and data transmission paths to users. These hybrid networks may be treated as network nodes for analysis purpose. The two radio access technologies (RATs) are considered with cellular/WLAN depending on whether it is voice/ data, video. For observing practical result, some setups are required in laboratory which includes interface from personal computer to mobile terminal and vice-versa. The network simulator (Ns-2) is used for analysis purpose. The results shows the parameters like energy good put, Bandwidth utilization, packet delivery ratio, energy good put and energy consumed are improved after using hybrid networks.
Millimeter Wave Mobile Broadband: Unleashing 3-300 GHz SpectrumFarooq Khan
This presentation from IEEE Wireless Communications & Networking Conference in 2011 started the 5G conversation and busted many of the myths about millimeter waves and their applicability to mobile wireless communications.
Femtocell is a small cellular base station,designe d for use in residential or enterprise. Connects to the service provider�s network via broa dband.Femtocell is one type of Indoor network which provide the wireless access within th e particular area. Femtocells ensure that carefully planned cellular networks which may conne ct anespecially of the citizens to the Internet and with one another. In this paper femtoc ells has such network which maintains the specialty of the data transfer through the network will femtocells prove more trouble than they are worth,femtocells just an exciting but Minimum stage of network evolution that will beimproved Wireless offloading,new backhaul regula tions and/or pricing,or other unforeseen technological developments? This paper overviews th e history of femtocells,demystifies their key aspects,and provides a preview of the next few years� acceleration towards small cell technology. This paper reports,we also position an d introduce the articles that headline this special issue.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
In this thesis firstly we study the effects of Black hole attack in MANET using both Proactive and Reactive routing protocols and then discovering a Secure Path in MANET by Avoiding Black/Gray Holes. The impact of Black Hole attack on the performance of MANET is evaluated finding out which protocol is more vulnerable to the attack and how much is the impact of the attack on both protocols. blackhole route
Comparison of Various Unicast-Multicast Routing Protocols for Mobile Ad-Hoc N...Editor IJMTER
A Mobile Ad-hoc Network (MANET) is a self configuring network which consists of
mobile nodes with no permanent infrastructure. In a MANETs, there is no difference between a host
node and a router so that all nodes can be source plus forwarders of traffic. The task of finding routes
in Mobile Ad-hoc Network (MANET) is an important factor in determining the efficiency of any
MANET routing protocols. This paper describes about the basic idea of different routing protocols
and its efficient use in MANET. There are several routing protocols based on UNICAST and
MULTICAST. This paper will conclude the main characteristics of these protocols with comparison
and suggest the best suited protocol for particular topology or network.
Recent advances in wireless networks have led to the introduction of a new type of networks called Vehicular Networks. Vehicular Ad Hoc Network (VANET) is a form of Mobile Ad Hoc Networks (MANET). VANETs provide us with the infrastructure for developing new systems to enhance drivers’ and passengers’ safety and comfort. VANETs are distributed self organizing networks formed between moving vehicles equipped with wireless communication devices. This type of networks is developed as part of the Intelligent Transportation Systems (ITS) to bring significant improvement to the transportation systems performance. One of the main goals of the ITS is to improve safety on the roads, and reduce traffic congestion, waiting times, and fuel consumptions. The integration of the embedded computers, sensing devices, navigation systems (GPS), digital maps, and the wireless communication devices along with intelligent algorithms will help to develop numerous types of applications for the ITS to improve safety on the roads. The up to date information provided by the integration of all these systems helps drivers to acquire real-time information about road conditions allowing them to react on time. For example, warning messages sent by vehicles involved in an accident enhances traffic safety by helping the approaching drivers to take proper decisions before entering the crash dangerous zone (ElBatt et al., 2006) (Xu et al., 2007). And Information about the current transportation conditions facilitate driving by taking new routes in case of congestion, thus saving time and adjusting fuel consumption (Dashtinezhad et al., 2004) (Nadeem et al., 2004). In addition to safety concerns, VANET can also support other non-safety applications that require a Quality of Service (QoS) guarantee. This includes Multimedia (e.g., audio/video) and data (e.g., toll collection, internet access, weather/maps/ information) applications.
Vehicular networks are composed of mobile nodes, vehicles equipped with On Board Units (OBU), and stationary nodes called Road Side Units (RSU) attached to infrastructure that will be deployed along the roads.
The International Journal of Engineering and Science (The IJES)theijes
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
GLOBAL FRONTRUNNER ROUTING ALGORITHM (GFRA) FOR V2V COMMUNICATION IN VANETS cscpconf
VANET (Vehicular Ad hoc NETwork) is the emerging research area that making the phrase
“Network on Wheel” true. In this new age network the basic WLAN (IEEE 802.11) standard is
used. As the necessity of such network increases the implementation challenges are being taken
into account. They are broadcasting, routing, priority scheduling and security and privacy. In
this paper the routing is considered as the research factor. A proposal for routing with
frequently changing topology to avoid disconnection of network on road and for the routing
among overlapping networks in flyovers with multiple ramps and stack to avoid wrong
messaging is given.
GLOBAL FRONTRUNNER ROUTING ALGORITHM (GFRA) FOR V2V COMMUNICATION IN VANETS cscpconf
VANET (Vehicular Ad hoc NETwork) is the emerging research area that making the phrase
“Network on Wheel” true. In this new age network the basic WLAN (IEEE 802.11) standard is
used. As the necessity of such network increases the implementation challenges are being taken
into account. They are broadcasting, routing, priority scheduling and security and privacy. In
this paper the routing is considered as the research factor. A proposal for routing with
frequently changing topology to avoid disconnection of network on road and for the routing among overlapping networks in flyovers with multiple ramps and stack to avoid wrong messaging is given.
IOSR Journal of Computer Engineering (IOSR-JCE) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of computer engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in computer technology. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Connector Corner: Automate dynamic content and events by pushing a buttonDianaGray10
Here is something new! In our next Connector Corner webinar, we will demonstrate how you can use a single workflow to:
Create a campaign using Mailchimp with merge tags/fields
Send an interactive Slack channel message (using buttons)
Have the message received by managers and peers along with a test email for review
But there’s more:
In a second workflow supporting the same use case, you’ll see:
Your campaign sent to target colleagues for approval
If the “Approve” button is clicked, a Jira/Zendesk ticket is created for the marketing design team
But—if the “Reject” button is pushed, colleagues will be alerted via Slack message
Join us to learn more about this new, human-in-the-loop capability, brought to you by Integration Service connectors.
And...
Speakers:
Akshay Agnihotri, Product Manager
Charlie Greenberg, Host
Securing your Kubernetes cluster_ a step-by-step guide to success !KatiaHIMEUR1
Today, after several years of existence, an extremely active community and an ultra-dynamic ecosystem, Kubernetes has established itself as the de facto standard in container orchestration. Thanks to a wide range of managed services, it has never been so easy to set up a ready-to-use Kubernetes cluster.
However, this ease of use means that the subject of security in Kubernetes is often left for later, or even neglected. This exposes companies to significant risks.
In this talk, I'll show you step-by-step how to secure your Kubernetes cluster for greater peace of mind and reliability.
Generating a custom Ruby SDK for your web service or Rails API using Smithyg2nightmarescribd
Have you ever wanted a Ruby client API to communicate with your web service? Smithy is a protocol-agnostic language for defining services and SDKs. Smithy Ruby is an implementation of Smithy that generates a Ruby SDK using a Smithy model. In this talk, we will explore Smithy and Smithy Ruby to learn how to generate custom feature-rich SDKs that can communicate with any web service, such as a Rails JSON API.
Epistemic Interaction - tuning interfaces to provide information for AI supportAlan Dix
Paper presented at SYNERGY workshop at AVI 2024, Genoa, Italy. 3rd June 2024
https://alandix.com/academic/papers/synergy2024-epistemic/
As machine learning integrates deeper into human-computer interactions, the concept of epistemic interaction emerges, aiming to refine these interactions to enhance system adaptability. This approach encourages minor, intentional adjustments in user behaviour to enrich the data available for system learning. This paper introduces epistemic interaction within the context of human-system communication, illustrating how deliberate interaction design can improve system understanding and adaptation. Through concrete examples, we demonstrate the potential of epistemic interaction to significantly advance human-computer interaction by leveraging intuitive human communication strategies to inform system design and functionality, offering a novel pathway for enriching user-system engagements.
GraphRAG is All You need? LLM & Knowledge GraphGuy Korland
Guy Korland, CEO and Co-founder of FalkorDB, will review two articles on the integration of language models with knowledge graphs.
1. Unifying Large Language Models and Knowledge Graphs: A Roadmap.
https://arxiv.org/abs/2306.08302
2. Microsoft Research's GraphRAG paper and a review paper on various uses of knowledge graphs:
https://www.microsoft.com/en-us/research/blog/graphrag-unlocking-llm-discovery-on-narrative-private-data/
LF Energy Webinar: Electrical Grid Modelling and Simulation Through PowSyBl -...DanBrown980551
Do you want to learn how to model and simulate an electrical network from scratch in under an hour?
Then welcome to this PowSyBl workshop, hosted by Rte, the French Transmission System Operator (TSO)!
During the webinar, you will discover the PowSyBl ecosystem as well as handle and study an electrical network through an interactive Python notebook.
PowSyBl is an open source project hosted by LF Energy, which offers a comprehensive set of features for electrical grid modelling and simulation. Among other advanced features, PowSyBl provides:
- A fully editable and extendable library for grid component modelling;
- Visualization tools to display your network;
- Grid simulation tools, such as power flows, security analyses (with or without remedial actions) and sensitivity analyses;
The framework is mostly written in Java, with a Python binding so that Python developers can access PowSyBl functionalities as well.
What you will learn during the webinar:
- For beginners: discover PowSyBl's functionalities through a quick general presentation and the notebook, without needing any expert coding skills;
- For advanced developers: master the skills to efficiently apply PowSyBl functionalities to your real-world scenarios.
Accelerate your Kubernetes clusters with Varnish CachingThijs Feryn
A presentation about the usage and availability of Varnish on Kubernetes. This talk explores the capabilities of Varnish caching and shows how to use the Varnish Helm chart to deploy it to Kubernetes.
This presentation was delivered at K8SUG Singapore. See https://feryn.eu/presentations/accelerate-your-kubernetes-clusters-with-varnish-caching-k8sug-singapore-28-2024 for more details.
Knowledge engineering: from people to machines and back
Q0173299104
1. IOSR Journal of Computer Engineering (IOSR-JCE)
e-ISSN: 2278-0661,p-ISSN: 2278-8727, Volume 17, Issue 3, Ver. II (May – Jun. 2015), PP 99-104
www.iosrjournals.org
DOI: 10.9790/0661-173299104 www.iosrjournals.org 99 | Page
A Hybrid Approach for Performance Enhancement of VANET
using CSMA-MACA: a Review
Sheenam Arora1
, Chakshu Goel², Benu3
1
(M.Tech Scholar, Department of ECE, SBSSTC, Ferozepur (Pb.), India)
2
(Assistant Professor, Department of ECE, SBSSTC, Ferozepur (Pb.), India)
3
(Lecturer, Department of ECE, SBSSTC Poly wing, Ferozepur (Pb.), India)
Abstract: A wireless sensor network (WSNs) have increased gigantic consideration for their extensive variety
of utilization, for example, environmental checking, military consideration, medical services, fiasco
administration and so forth .A Vehicular ad hoc network (VANET) utilizes cars as versatile nodes as a part of a
MANET to make a portable system. A VANET transforms each partaking car into a remote or switch or node,
permitting cars pretty nearly100 to 300 meters of one another to associate and, thus, make a system with a wide
range. In wireless networking, the shrouded node issue or concealed terminal issue happens when a node is
obvious from a wireless access point(AP), yet not from different nodes communicating with that AP.In our work
we will dispose of the issue of concealed terminal node issue.
Keywords: AODV, Hidden terminal node, VANET’s, WSN.
I. Introduction
A wireless network is any sort of PC system that uses remote information associations for associating
system hubs. Remote systems administration is a system by which homes, information transfers systems and
endeavor (business) establishments evade the unreasonable methodology of bringing links into a building, or as
an association between different supplies locations. Wireless information transfers systems are by and large
actualized and controlled utilizing radio communication.
II. Types of Wireless Networks
2.1 Wireless PAN
Wireless personal area networks (WPANs) interconnect gadgets inside a moderately little region that is
for the most part inside an individual's reach. For instance, both Bluetooth radio and undetectable infrared light
gives a WPAN to interconnecting a headset to a portable computer. Zig Bee likewise underpins WPAN
applications. Wi-Fi PANs are getting to be typical (2010) as gear originators begin to coordinate Wi-Fi into a
mixed bag of purchaser electronic gadgets. Intel "My Wi-Fi" and Windows 7"virtual Wi-Fi" abilities have made
Wi-Fi PANs easier and simpler to set up and design.
2.2 Wireless LAN
A wireless local area network joins two or more gadgets over a short separation utilizing a remote
conveyance system, generally giving an association through a right to gain entrance point for Internet access.
The utilization of spread-range or OFDM advances may permit clients to move around inside a neighborhood
scope zone, and still stay joined with the system. Items utilizing the IEEE 802.11 WLAN guidelines are
advertised under the Wi-Fi brand name. Settled remote innovation actualizes point-to-point interfaces between
PCs or systems at two removed areas, regularly utilizing committed microwave or tweaked laser light pillars
over observable pathway ways. It is frequently utilized as a part of urban communities to associate systems in
two or more structures without introducing a wired connection.
2.3 Wireless Mesh network
A wireless mesh network is a remote system made up of radio hubs composed in a lattice topology.
Every hub advances messages for the benefit of alternate hubs. Cross section systems can "self recuperate",
naturally re-directing around a hub that has lost force.
III. Properties OF WSN
3.1 Performance
Every standard differs in geographical range, subsequently making one standard more perfect than the
following relying upon what it is one is attempting to finish with a remote network. The execution of remote
systems fulfills a mixture of uses, for example, voice and feature. The utilization of this innovation likewise
gives space for extensions, for example, from 2G to 3Gand, most as of late, 4G innovation, which remains for
2. A Hybrid Approach for Performance Enhancement of VANET using CSMA-MACA: a Review
DOI: 10.9790/0661-173299104 www.iosrjournals.org 100 | Page
fourth era of mobile phone versatile correspondences measures. As remote systems administration has gotten to
be typical, refinement increments through design of system equipment and programming, and more noteworthy
ability to send and get bigger measures of information, speedier, is achieved.
3.2 Space
Space is an alternate normal for remote systems administration. Remote systems offer numerous points
of interest with regards to hard to-wire regions attempting to impart, for example, over a road or waterway, a
stockroom on the opposite side of the reason or structures that are physically divided however work as one.
Remote systems take into account clients to assign a certain space which the system will have the capacity to
speak with different gadgets through that system. Space is likewise made in homes as a consequence of
dispensing with jumbles of wiring. This innovation takes into account an option to introducing physical system
mediums, for example, TPs, cajoles, or fiber-optics, which can likewise be lavish.
IV. VANET
A vehicular ad hoc network (VANET) utilizes autos as versatile hubs in a MANET to make a portable
system. A VANET transforms each taking an interest auto into a remote switch or hub, permitting autos more or
less 100 to 300 meters of one another to unite and, thus, make a system with a wide range. As autos drop out of
the sign range and drop out of the system, different autos can join in, joining vehicles to each other so that a
portable Internet is made. It is assessed that the first frameworks that will incorporate this innovation are police
and fire vehicles to speak with one another for security purposes.
4.1 High Dynamic Topology
The topology of VANET changes due to the development of vehicles at high speed. Suppose two
vehicles are moving at the pace of 20m/sec and the radio range between them is 160 m. At that point the
connection between the two vehicles will last 160/20 = 8 sec.
4.2 Frequent disconnected network
From the very dynamic topology results we watch that successive disconnection happen between two
vehicles when they are trading data. This disconnection will happen most in inadequate system.
4.3 Mobility modeling
The versatility example of vehicles relies on upon activity environment, streets structure, the rate of vehicles,
driver's driving conduct etc.
4.4 Battery power and storage capacity
In advanced vehicles battery force and capacity is boundless. Subsequently it has enough figuring force which is
distracted in MANET. It is useful for successful correspondence & settling on directing choices.
4.5 Communication Environment
The correspondence environment between vehicles is distinctive in scanty system & thick system. In
thick system building, trees & different articles act as hindrances and in inadequate system like high-way this
things are non attendant. So the steering methodology of scanty & thick system will be diverse.
4.6 Interaction with onboard sensors
The current position & the development of hubs can without much of a stretch be sensed by installed sensors
like GPS gadget. It helps for compelling correspondence and steering choices.
V. Hidden Terminal Problem
In Fig. 1, transmitter TX1 and transmitter TX2 are out of radio range of each other, i.e., they are hidden
to one another. Therefore they may access the medium at the same time, making the receivers RX1-RX3
experience a data collision, i.e., being unable to decode any of the two packets. This phenomenon is termed the
hidden terminal problem and in wireless ad hoc networks, it can occur regardless of MAC method.
3. A Hybrid Approach for Performance Enhancement of VANET using CSMA-MACA: a Review
DOI: 10.9790/0661-173299104 www.iosrjournals.org 101 | Page
Fig.1 Hidden Terminal Problem
VI. Related Work
6.1 Related work
Bhatt, U.R. et al [1] "ONU arrangement in Fiber-Wireless (Fi-Wi) Networks" as of late, there is a
touchy development in a web clients which oblige a broadband access system with high limit and better
adaptability and gets benefit in "anyplace at whatever time" way. The arrangement is a FIWI innovation which
substantiating itself a principle apparatus in the field of telecom by its own benefits over the other existing
advances. Fiber-Wireless (FiWi) Network is a blend of Passive Optical Network (PON) and Wireless Mesh
Network (WMN). It gives vast transmission capacity limit and high steadiness in optical system and lower cost
in remote system. In this way, Fi-Wi offers clients to broadband access benefit in an "anyplace at whatever
time" way. In this paper, the principle concentrates on the ONU situation in Fi-Wi system to make an expense
effective system. The key issue in FiWi system is the arrangement of optical system unit (ONU) since ONU
gives interface between the optical system and wireless system. The arrangement of ONU assumes additionally
an essential part in system throughput.In Fi-Wi system, situation of ONU such that it help both sort of activity
i.e. Web activity and distributed (P2P) movement. Web movement means activity from the remote customer to
web and distributed movement means movement starting with one remote customer then onto the next remote
customer. In this paper, the related work done in ONU situation to help both sorts of activity and to minimizing
the quantities of ONU in a FiWi network is concentrated on.
Zhao Cheng et al [2] "Investigation and Optimization Model of Cognitive Wireless Mesh Networks"
Recently, much consideration has been committed to cognitive radio system (CRN) and thusly, it replenishes the
enthusiasm for enhancing the execution of remote lattice systems (WMNs). It has been demonstrated that
cognitive radio innovation consolidated with multi-radio multi-channel innovation is a guaranteeing route for
remote system execution change. In the meantime, they additionally prompt some new difficulties for system
building design configuration and convention improvement. This paper exhibits a multi-radio cognitive remote
lattice system structural engineering CR Mesh, which incorporates the cognitive radio (CR) innovation with
existing remote cross section system advancements consistently. A 3G Model is proposed, which can depict
CRN precisely from the point of view of bundle sending. The improvement issue of higher layer system control
conventions is investigated on the perspective of asset portion. A novel asset assignment plan and comparing
cross-layer advancement system are proposed. This paper exhibits a general plan of cognitive remote cross
section system structural planning configuration and convention advancement.
Abbas, F et al [3] "Protection mindful course following and disavowal diversions in VANET-based
mists" The predicted long for dependable, safe, and open to driving background is yet to end up reality since car
commercial ventures are trying their waters for VANET (Vehicular Ad Hoc Network) organization. Anyway by
the by, security and protection issues have been the underlying driver of obstacle in VANET deployment. As of
late, VANET advanced to VANET-based mists as a consequence of assets rich top of the line autos. Before
long, Hussain et al. characterized diverse building systems for VANET-based mists. In this paper, author goes
for a particular structure to be specific VUC (VANET utilizing Clouds) where VANET and CC (Cloud
Computing) participate with one another keeping in mind the end goal to give VANET clients with
administrations. Author was proposed a lightweight protection mindful disavowal and course following
component for VuC. Signals showed by vehicles are put away in cloud framework as collaboration from
VANET and in the wake of transforming, cloud gives VANET endorsers administrations. Denial powers can
disavow and follow the way taken by the target hub for a pointed out time span by abusing the signals put away
in the cloud. Our proposed plan is secure, jelly contingent security, and is computationally less costly than the
already proposed plans.
Craftsman, S.E.et al [4] "Hindrance Shadowing Influences in VANET Safety" Wireless interchanges
between vehicles empowers both wellbeing applications, for example, mischance evasion, and non safety
applications, for example, movement blockage alarms with the expectation of enhancing security in driving
conditions. Since expense restricted proving ground situations oblige model testing, VANET scientists regularly
4. A Hybrid Approach for Performance Enhancement of VANET using CSMA-MACA: a Review
DOI: 10.9790/0661-173299104 www.iosrjournals.org 102 | Page
turn rather to reproduction toolsets from which a rich set of ecological situations are displayed. Notwithstanding,
regardless of the accessibility of such apparatuses, results are conflicting. While VANET specialists regularly
demonstrate proliferation misfortune deterministically subordinate upon transmitter recipient separation,
blurring and shadowing impacts are frequently displayed stochastically, prompting probabilistic results which
are autonomous of the genuine environment and accordingly neglect to consider practical street topologies and
the vicinity of snags. In this work, we actualize for ns-3 [3] the exactly accepted hindrance shadowing model
from by leveraging building information from Open Street Map (OSM) to deterministically assess observable
pathway spread impacts utilizing methods from computational geometry, and we further stretch out results to
assess wellbeing execution evaluations. The effect to security execution estimation of snags in VANET
reenactments inspires the accompanying examination objective: The objective of this exploration is to show
quantitatively how precise, deterministic hindrance blurring models affect the execution appraisal of VANET
wellbeing applications. Counting reasonable deterrent shadowing in VANET reproduction demonstrating
enhances VANET evaluation and reinforces wellbeing, along these lines supporting one of the essential
objectives of joined vehicle frameworks.
Siyue Chen et al [5] "Estimation of Packet Loss Rate at Wireless Link of VANET—RPLE" Vehicular
Ad hoc Network (VANET), as a subclass of portable Ad hoc Networks (MANETs), is a guaranteeing
methodology for movement security, versatile web and V2V correspondence. While the bundle misfortune
estimation of VANET effects directing convention and transmission control calculation, it just so happens to be
an essential issue. In this paper, author was proposed an estimation calculation for bundle misfortune on
VANET, RPLE (Real time parcel misfortune estimation), which utilizes few test bundles and improve the
estimation precision than conventional routines for bundle misfortune on remote systems. Because of hub
movement and complex radio environment, bundle misfortune estimation in VANET is a hard issue. On the
other hand, parcel misfortune estimation effects directing convention and transmission control calculation of
VANET, so it is a critical issue. In light of mass on-street estimations, we have gotten the general factual
principals of parcel misfortune rate (PLR) by separations on VANET, and we utilize Gaussian Mixture Model
(GMM) to present PLR likelihood thickness. All things considered, to get ongoing PLR by sending a couple of
test parcels, RPLE use greatest a posteriori likelihood strategy to gauge the current PLR focused around the
GMM of PLR likelihood thickness and the testing result. In genuine urban street situation, the investigation
results indicate that RPLE can get more precise PLR estimation by few test parcels instantly.
Vijayakarthika, R. et al [6] "Vehicular impromptu systems (VANETs) are a developing innovation that
gives productive and solid information correspondence between vehicles utilizing Roadside units (RSU). In any
case it obliges proficient and powerful steering conventions for their correspondence. We abuse the altered base
of Roadside units (RSUs) to proficiently and dependably course parcels in VANETs. All the RSUs are
interconnected with one another. Our VANET framework works by utilizing vehicles to convey and forward
messages from a source vehicle to a close-by RSU and, if necessary, course these messages through the RSU
system and, at long last send them from a RSU to the end of the line vehicle. All the RSUs are interconnected
with one another. To actualize the same vehicle correspondence with server based way. By our server based
system the vanet correspondence will be more successful. The separate will reaction for table support that
information in its information base. In our task idea we have the opportunity to lessened deferral with boosted
throughput in VANET furthermore we can ready to anticipate the activity thickness of specific range of our
system. We assess the execution of our framework utilizing the ns2 recreation and contrast our result and
existing framework.
VII. Approaches Used
7.1 AODV
In AODV, the system is quiet until a connection is required. By then the network node that needs a
connection telecasts an appeal for connection. Other AODV nodes forward this message, and record the node
that they heard it from, making a blast of short term routes back to the needy node. At the point when a node
gets such a message and has a route to the wanted node, it communicates something specific rearward through
an impermanent route to the asking for node. The needy node then starts utilizing the route that has the slightest
number of hops through different nodes. Unused passages in the routing tables are reused after a period. At the
point when a connection falls flat, a routing error is passed once more to a transmitting node, and the process
repeats.
7.2 OSP
Open Street Map is an activity to make and give free geographic data, for example, street maps, to
anybody. The Open Street Map Foundation is an universal not-revenue driven association supporting, yet not
controlling, the Open Street Map Project. It is devoted to empowering the development, advancement and
conveyance of free geospatial data and to giving geospatial data to anybody to utilize.
5. A Hybrid Approach for Performance Enhancement of VANET using CSMA-MACA: a Review
DOI: 10.9790/0661-173299104 www.iosrjournals.org 103 | Page
7.3 CSMA
The term ―Carrier Sense‖ signifies the capability of the terminal to listen to the channel and find out
whether it is busy or not. At first sight it seems that with CSMA one can succeed in avoiding collisions
altogether. Indeed, if all terminals transmit their packets only when the channel is not busy and pick a random
retransmission time if they find the channel busy, then it seems that a collision will occur only when two or
more terminals begin transmission simultaneously, an event that is quite unlikely. However, the situation is not
as rosy as it seems, due to the finite duration it takes for a signal to spread from one terminal to another. The
modified CSMA system, whose principles of operation were described above, comes by the name CSMA/CA,
where CA stands for Collision Avoidance. The acronym signifies that collisions are sought to be avoided and
not that they are avoided altogether. Due to the retransmission policy of the CSMA system, collisions that may
occur are not detrimental: in case of collision, the ACK message or RTS CTS messages will not be received and
the transmitting terminal will defer its transmission for a later time. However, if the propagation delays are
relatively large and the system is heavily loaded, collisions may degrade the performance of the system.
7.4 MACA
MACA does not make use of carrier-sensing for channel access. It uses two additional signaling
packets: the Request-To-Send (RTS) packet and Clear-To-Send (CTS) packet. When a node wants to transmit
data packet, it first transmits an RTS packet. The receiver node, on accepting RTS packet, in the event that it is
prepared to get the data packet, transmits a CTS packet. Once the sender gets the CTS packet with no mistake, it
begins transmitting the data packet. On the off chance that a data transmitted by a node is lost, the node utilizes
the binary exponential back-off (BEB) algorithm to back-off for an irregular interim of time before retrying. In
the BEB mechanism each time a collision is detected, the node doubles its maximum back-off window.
Neighbor nodes near the sender that hear the RTS packet do not transmit for a long enough period of time so
that the sender could receive the CTS packet. Both, RTS and the CTS packets convey the normal length of time
of the data packet transmission. A node the receiver, after listening to the CTS packet, concedes its transmission
till the recipient gets the data packet. Thus, MACA overcomes the hidden terminal problem. Similarly, a node
receiving an RTS defers only for a short period of time till the sender could receive the CTS. If the node hears
NO CTS during its waiting period, it is free to transmit packets once the waiting interval is over. Thus a node
that hears only the RTS packet is free to transmit simultaneously when the sender of the RTS is transmitting
data packets. Hence the exposed terminal problem is also overcome in MACA.
7.5 DSRC
The primary motivation for deploying DSRC is to enable collision prevention applications. These
applications depend on frequent data exchanges among vehicles, and between vehicles and roadside
infrastructure DSRC, which is a candidate for use in a VANET, is a short to medium range communication
service that supports both public safety and private communication. The communication environment of DSRC
is both vehicle-to-vehicle and vehicle-to/from-roadside. The VANET plans to give a high data rate and in the
meantime minimize inactivity inside a generally little communication zone Dedicated Short-Range
Communication (DSRC) is a standard that intends to bring vehicular networks to North America. Activity
fatalities have been a long standing issue in the United States, as in whatever remains of the world. As a sign of
the seriousness of the issue, in 1999 there were 6,279,000 engine vehicle mischance’s that represented 41,611
passing in the United States. In 1991, the US Congress passed the Intermodal Surface Transportation Efficiency
Act of 1991 that brought about the creation the original of Intelligent Transportation System (ITS). The
objective of the ITS system is to consolidate innovation into the transportation base to enhance wellbeing.
VIII. Conclusion
The concealed terminal issue is regularly said to be the significant restricting execution figure in
vehicular ad hoc networks. In vehicular ad hoc networks (VANET) the hidden terminal problem is not as
straight forward to define. The term ―Carrier Sense‖ signifies the capability of the terminal to listen to the
channel and find out whether it is busy or not. MACA does not make use of carrier-sensing for channel access.
It uses two additional signaling packets: the Request-To-Send (RTS) packet and the Clear-To-Send (CTS)
packet. We will enhance our work by using hybrid CSMA + MACA protocol in VANET to solve the hidden
terminal problem.
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