MAR SECURITY: IMPROVED SECURITY MECHANISM FOR EMERGENCY MESSAGES OF VANET USI...IJCNCJournal
Vehicular Ad-hoc network (VANET) is one of the emerging technologies for research community to get various research challenges to construct secured framework for autonomous vehicular communication. The prime concern of this technology is to provide efficient data communication among registered vehicle nodes. The several research ideas are implemented practically to improve overall communication in VANETs by considering security and privacy as major aspects of VANETs. Several mechanisms have been implemented using cryptography algorithms and methodologies. However, these mechanisms provide a solution only for some restricted environments and to limited security threats. Hence, the proposed novel mechanism has been introduced, implemented and tested using key management technique. It provides secured network environment for VANET and its components. Later, this mechanism provides security for data packets of emergency messages using cryptography mechanism. Hence, the proposed novel mechanism is named Group Key Management & Cryptography Schemes (GKMC). The experimental analysis shows significant improvements in the network performance to provide security and privacy for emergency messages. This GKMC mechanism will help the VANET user’s to perform secured emergency message communication in network environment.
STUDY OF VANET ROUTING PROTOCOLS FOR END TO END DELAYcscpconf
Less than a century since the automobile was made affordable enough for the general public, hundreds of millions of vehicles now travel along highways and streets around the
world. Innovations in safety, comfort, and convenience have made vast improvements in
automobiles during that time, and now new technologies promise to change the face of
vehicular travel once again. Vehicular ad hoc network (VANET) is network which provides the communication between vehicle to vehicle for p r o v i d i n g i n f o r m a t i o n t o travelers with new features and applications that have never previously been possible. This paper focuses
on vehicle to vehicle (V2V) communications in VANET. Lot of research is going on for
determining route between source and destination vehicles for routing the information with
good packet delivery ratio. In this paper we provide a simulation and study of VANET Routing Protocols for end-to-end delay in V2V communication.
Study of vanet routing protocols for end to end delaycsandit
Less than a century since the automobile was made affordable enough for the general
public, hundreds of millions of vehicles now travel along highways and streets around the
world. Innovations in safety, comfort, and convenience have made vast improvements in
automobiles during that time, and now new technologies promise to change the face of
vehicular travel once again. Vehicular ad hoc network (VANET) is network which provides the
communication between vehicle to vehicle for p r o v i d i n g i n f o rma t i o n t o travelers with
new features and applications that have never previously been possible. This paper focuses
on vehicle to vehicle (V2V) communications in VANET. Lot of research is going on for
determining route between source and destination vehicles for routing the information with
good packet delivery ratio. In this paper we provide a simulation and study of VANET Routing
Protocols for end-to-end delay in V2V communication.
An Optimal Route Discovery using Biogeography based Optimization for Vehicula...StevePrice20
Vehicular ad hoc network (VANET) is a subdivision of the mobile ad hoc networks which uses the moving vehicles as mobile nodes to form the mobile network. In conventional vehicular communications, the restricted radio frequency bandwidth affects the network performances. Therefore, Visible Light Communication (VLC) is integrated with the growing vehicular ad hoc network to obtain high data rate and less energy consumption during the communication. In this paper, vehicular communication is integrated with visible light communication to avoid the issues caused by the restricted radio frequency bandwidth. Moreover, the Routing using Biogeography Based Optimization (RBBO) is proposed to develop an optimal route between the source vehicles to the destination. This research performs two different communications such as vehicle to vehicle and vehicle to the infrastructure. The performance of the RBBOVLC-VANET method is analyzed by means of throughput, packet delivery ratio, delay and routing overhead as well as these performances are compared with the existing method namely ant colony optimization based routing protocol. The throughput of the routing using the biogeography based optimization method is 589.763 kbps for 500 nodes which is high when compared to the existing method.
Vehicular adhoc network (VANET) adopts or resembles a similar structure of Mobile adhoc network (MANET). The communication in VANET are generally classified into following three categories such as Vehicle to Infrastructure (V2I), Vehicle to Vehicle (V2V) and Hybrid network which is a combination of V2V and V2I network. VANET using the IEEE 802.11p standard has great potential of achieving objectives of Smart intelligent transport system (SITS) for improving transport and road safety efficiency. As more and more services is been provided for V2V based VANET network. It is a challenging task to provide QoS to end user, due to wireless medium that has limited channel availability for transmission. To guarantee QoS and provide efficient network performance, a prioritized MAC need to be designed. Many priority based MAC has been designed in recent times to improve the quality of data delivery to end user. However these do not consider the impact of environment and presence of obstacle which affects the signal attenuation at the receiver end and affecting the QoS of channel availability. To address, this work present an obstacle based radio propagation model, obstacle based CEV (City, Expressway and Village) environmental model and a selective MAC to provide QoS for different services. The proposed model efficiency is evaluated in term of throughput achieved per channel, Collison and success packet transmission. To evaluate the adaptive performance of proposed AMACexperiment are conducted under CEV environment and are compared with existing MAC NCCMA. The outcome achieved shows that the proposed model is efficient in term of reducing Collison, improving packet transmission and throughput performance considering two types of services.
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology.
STUDY OF THE EFFECT OF VELOCITY ON END-TOEND DELAY FOR V2V COMMUNICATION IN ITSijngnjournal
This paper focuses on vehicle to vehicle (V2V) communications in VANET. With the development of vehicles and mobile Ad Hoc network technology, the Vehicle Ad hoc Network (VANET) has become an emerging field of study. VANET is a special case of MANET, and will play an important role in city road traffic control. It is a challenging problem for searching and maintaining an effective route for transporting data information. Vehicular Ad Hoc network (VANET), is a hot topic applying mobile Ad Hoc network (MANET) to ITS in recent years. In the era of wireless computing, VANET communications are gaining a lot of attention. In this paper we provide a simulation and study of the effect of velocity on end-to-end delay for v2v communication in intelligent transportation Systems
MAR SECURITY: IMPROVED SECURITY MECHANISM FOR EMERGENCY MESSAGES OF VANET USI...IJCNCJournal
Vehicular Ad-hoc network (VANET) is one of the emerging technologies for research community to get various research challenges to construct secured framework for autonomous vehicular communication. The prime concern of this technology is to provide efficient data communication among registered vehicle nodes. The several research ideas are implemented practically to improve overall communication in VANETs by considering security and privacy as major aspects of VANETs. Several mechanisms have been implemented using cryptography algorithms and methodologies. However, these mechanisms provide a solution only for some restricted environments and to limited security threats. Hence, the proposed novel mechanism has been introduced, implemented and tested using key management technique. It provides secured network environment for VANET and its components. Later, this mechanism provides security for data packets of emergency messages using cryptography mechanism. Hence, the proposed novel mechanism is named Group Key Management & Cryptography Schemes (GKMC). The experimental analysis shows significant improvements in the network performance to provide security and privacy for emergency messages. This GKMC mechanism will help the VANET user’s to perform secured emergency message communication in network environment.
STUDY OF VANET ROUTING PROTOCOLS FOR END TO END DELAYcscpconf
Less than a century since the automobile was made affordable enough for the general public, hundreds of millions of vehicles now travel along highways and streets around the
world. Innovations in safety, comfort, and convenience have made vast improvements in
automobiles during that time, and now new technologies promise to change the face of
vehicular travel once again. Vehicular ad hoc network (VANET) is network which provides the communication between vehicle to vehicle for p r o v i d i n g i n f o r m a t i o n t o travelers with new features and applications that have never previously been possible. This paper focuses
on vehicle to vehicle (V2V) communications in VANET. Lot of research is going on for
determining route between source and destination vehicles for routing the information with
good packet delivery ratio. In this paper we provide a simulation and study of VANET Routing Protocols for end-to-end delay in V2V communication.
Study of vanet routing protocols for end to end delaycsandit
Less than a century since the automobile was made affordable enough for the general
public, hundreds of millions of vehicles now travel along highways and streets around the
world. Innovations in safety, comfort, and convenience have made vast improvements in
automobiles during that time, and now new technologies promise to change the face of
vehicular travel once again. Vehicular ad hoc network (VANET) is network which provides the
communication between vehicle to vehicle for p r o v i d i n g i n f o rma t i o n t o travelers with
new features and applications that have never previously been possible. This paper focuses
on vehicle to vehicle (V2V) communications in VANET. Lot of research is going on for
determining route between source and destination vehicles for routing the information with
good packet delivery ratio. In this paper we provide a simulation and study of VANET Routing
Protocols for end-to-end delay in V2V communication.
An Optimal Route Discovery using Biogeography based Optimization for Vehicula...StevePrice20
Vehicular ad hoc network (VANET) is a subdivision of the mobile ad hoc networks which uses the moving vehicles as mobile nodes to form the mobile network. In conventional vehicular communications, the restricted radio frequency bandwidth affects the network performances. Therefore, Visible Light Communication (VLC) is integrated with the growing vehicular ad hoc network to obtain high data rate and less energy consumption during the communication. In this paper, vehicular communication is integrated with visible light communication to avoid the issues caused by the restricted radio frequency bandwidth. Moreover, the Routing using Biogeography Based Optimization (RBBO) is proposed to develop an optimal route between the source vehicles to the destination. This research performs two different communications such as vehicle to vehicle and vehicle to the infrastructure. The performance of the RBBOVLC-VANET method is analyzed by means of throughput, packet delivery ratio, delay and routing overhead as well as these performances are compared with the existing method namely ant colony optimization based routing protocol. The throughput of the routing using the biogeography based optimization method is 589.763 kbps for 500 nodes which is high when compared to the existing method.
Vehicular adhoc network (VANET) adopts or resembles a similar structure of Mobile adhoc network (MANET). The communication in VANET are generally classified into following three categories such as Vehicle to Infrastructure (V2I), Vehicle to Vehicle (V2V) and Hybrid network which is a combination of V2V and V2I network. VANET using the IEEE 802.11p standard has great potential of achieving objectives of Smart intelligent transport system (SITS) for improving transport and road safety efficiency. As more and more services is been provided for V2V based VANET network. It is a challenging task to provide QoS to end user, due to wireless medium that has limited channel availability for transmission. To guarantee QoS and provide efficient network performance, a prioritized MAC need to be designed. Many priority based MAC has been designed in recent times to improve the quality of data delivery to end user. However these do not consider the impact of environment and presence of obstacle which affects the signal attenuation at the receiver end and affecting the QoS of channel availability. To address, this work present an obstacle based radio propagation model, obstacle based CEV (City, Expressway and Village) environmental model and a selective MAC to provide QoS for different services. The proposed model efficiency is evaluated in term of throughput achieved per channel, Collison and success packet transmission. To evaluate the adaptive performance of proposed AMACexperiment are conducted under CEV environment and are compared with existing MAC NCCMA. The outcome achieved shows that the proposed model is efficient in term of reducing Collison, improving packet transmission and throughput performance considering two types of services.
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology.
STUDY OF THE EFFECT OF VELOCITY ON END-TOEND DELAY FOR V2V COMMUNICATION IN ITSijngnjournal
This paper focuses on vehicle to vehicle (V2V) communications in VANET. With the development of vehicles and mobile Ad Hoc network technology, the Vehicle Ad hoc Network (VANET) has become an emerging field of study. VANET is a special case of MANET, and will play an important role in city road traffic control. It is a challenging problem for searching and maintaining an effective route for transporting data information. Vehicular Ad Hoc network (VANET), is a hot topic applying mobile Ad Hoc network (MANET) to ITS in recent years. In the era of wireless computing, VANET communications are gaining a lot of attention. In this paper we provide a simulation and study of the effect of velocity on end-to-end delay for v2v communication in intelligent transportation Systems
On the real time hardware implementation feasibility of joint radio resource ...IEEEFINALYEARPROJECTS
To Get any Project for CSE, IT ECE, EEE Contact Me @ 09849539085, 09966235788 or mail us - ieeefinalsemprojects@gmail.co¬m-Visit Our Website: www.finalyearprojects.org
A Modified Fault Tolerant Location-Based Service Discovery Protocol for Vehic...acijjournal
In the recent years, advances in Vehicular networks have attracted special attraction of researchers. Lately two types of applications have gain popularity: Road safety and Driving comfort. Reliable data transformation in the city environment is hard to accomplish due to presence of noise and obstacles. In
addition transient or permanent faults of vehicles or roadside routers (road components) are unavoidable, so we need a fault tolerant algorithm to overcome such failures. Although utilizing faulttolerant techniques cause to more efficiency and reliability in service discovery for vehicle networks, there are many few service discovery algorithms that have considered fault- tolerant techniques. In this paper we have improved one of these algorithms which is named Fault-Tolerant Location-Based
Vehicular Service Discovery Protocol (FLocVSD) in order to being more reliable.
International Journal of Computational Engineering Research (IJCER) ijceronline
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology
Performance Evaluation of GPSR Routing Protocol for VANETs using Bi-direction...CSCJournals
Routing in Vehicular Adhoc Networks is a challenging task where the nodes themselves are vehicles. The mobility factors such as beacon intervals and vehicles with different velocities may cause inaccuracy in the identification of the vehicle's position. This in turn affects the performance of the position based routing protocols. Further, there is a need to evaluate through simulations performance of the position based routing protocol, especially in urban realistic scenarios for VANETs. The work in this paper evaluates the performance of Greedy Perimeter Stateless Routing protocol (GPSR) for VANETs which is a popular position based protocol especially for routing in MANETs. In order to evaluate realistic simulation environment bi-directional coupling of OMNET++/ INET Framework and SUMO is chosen for Nagarbhavi region in Bengaluru, India. The simulations are done for various scenarios realizing the impact of mobility parameters on routing using GPSR, and performance is measured in terms of packet delivery ratio and throughput.
CROSS LAYER DESIGN APPROACH FOR EFFICIENT DATA DELIVERY BASED ON IEEE 802.11P...pijans
Intelligent Transportation Systems (ITS) have been one of the promising technology that has a great interest attention from many researchers over the world. Vehicular Ad-hoc Network (VANET) communications environment as a part of ITS opens the way for a wide range of applications such as safety applications, mobility and connectivity for both driver and passengers to exploit the transport systems in a smoothly, efficiently and safer way. Several challenging tasks facing adopting VANET functionality for ITS such as modelling of wireless transmission and routing issues. These research issues have become more critical due to the high mobility of vehicles nodes (transmitters and receivers) and unexpected network topology due to the high speed of nodes. In fact, modelling radio propagation channel in VANET environment which considers as one of a stringent communications environment is a challenging task. The selection of a suitable transmission model plays a key role in the routing decisions for VANET. Different propagation models allow calculating the Received Signal Strength (RSS) based on key environmental properties such as the distance between transmitter vehicle and a receiver vehicle, the gain and antenna height of transmitter and a receiver vehicles. Hence, it is useful to calculate RSS and SNR values for a specific propagation model and then these values can be used later for routing decision in order to find the best path with high SNR. This paper evaluates the performance of different transmission models (freespace, two-ray and log-normal) in terms of Receive Signal Strength (RSS). In addition, the performance of such wireless transmission models for vehicular communication in terms of PDR, throughput and delay is evaluated by applying the proposed cross layer routing approach based on IEEE 802.11p. By using MATLAB, the obtained results confirm the best packet delivery ratio for our proposed approach, where it indicates poor quality of DSSS PHY with high number vehicles. The minimum delay achieved when traffic density is decreased.
MECC scheduling algorithm in vehicular environment for uplink transmission in...IJECEIAES
Single Carrier Frequency Division Multiple Access (SC-FDMA) is chosen because of the lower peak-to-average power ratio (PAPR) value in uplink transmission. However, the contiguity constraint is one of the major constraint presents in uplink packet scheduling, where all RBs allocated to a single UE must be contiguous in the frequency-domain within each time slot to maintain its single carrier. This paper proposed an uplink-scheduling algorithm namely the Maximum Expansion with Contiguity Constraints (MECC) algorithm, which supports both the RT and NRT services. The MECC algorithm is deployed in two stages. In the first stage, the RBs are allocated fairly among the UEs. The second stage allocates the RBs with the highest metric value and expands the allocation on both sides of the matrix, M with respect to the contiguity constraint. The performance of the MECC algorithm was observed in terms of throughput, fairness, delay, and Packet Loss Ratio (PLR) for VoIP, video and best effort flows. The MECC scheduling algorithm is compared to other algorithms namely the Round Robin (RR), Channel-Dependent First Maximum Expansion (CD-FME), and Proportional Fairness First Maximum Expansion (PF-FME). From here, it can be concluded that the MECC algorithm shows the best results among other algorithms by delivering the highest throughput which is up to 81.29% and 90.04% than CD-FME and RR scheduler for RT and NRT traffic respectively, having low PLR and delay which is up to 93.92% and 56.22% of improvement than CD-FME for the RT traffic flow. The MECC also has a satisfactory level of fairness for the cell-edge users in a vehicular environment of LTE network.
An Improved Greedy Parameter Stateless Routing in Vehicular Ad Hoc NetworkIJAAS Team
Congestion problem and packet delivery related issues in the vehicular ad hoc network environment is a widely researched problem in recent years. Many network designers utilize various algorithms for the design of ad hoc networks and compare their results with the existing approaches. The design of efficient network protocol is a major challenge in vehicular ad hoc network which utilizes the value of GPS and other parameters associated with the vehicles. In this paper GPSR protocol is improved and compared with the existing GPSR protocol and AODV protocol on the basis of various performance parameters like throughput of the network, delay and packet delivery ratio. The results also validate the performance of the proposed approach.
International Journal of Engineering and Science Invention (IJESI)inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online
Joint Routing and Congestion Control in Multipath Channel based on Signal to ...IJECEIAES
Routing protocol and congestion control in Transmission Control Protocol (TCP) have important roles in wireless mobile network performance. In wireless communication, the stability of the path and successful data transmission will be influenced by the channel condition. This channel condition constraints come from path loss and the multipath channel fading. With these constraints, the algorithm in the routing protocol and congestion control is confronted with the uncertainty of connection quality and probability of successful packet transmission, respectively. It is important to investigate the reliability and robustness of routing protocol and congestion control algorithms in dealing with such situation. In this paper, we develop a detailed approach and analytical throughput performance with a cross layer scheme (CLS) between routing and congestion control mechanism based on signal to noise ratio (SNR) in Rician and Rayleigh as multipath fading channel. We proposed joint routing and congestion control TCP with a cross layer scheme model based on SNR (RTCP-SNR). We compare the performance of RTCP-SNR with conventional routing-TCP and routing-TCP that used CLS with routing aware (RTCP-RA) model. The analyses and the simulation results showed that RTCP-SNR in a multipath channel outperforms conventional routing-TCP and RTCP-RA.
Vehicular Ad-hoc Network (VANET) is a multi-hop
wireless ad-hoc network created by using mobile vehicles to
transmit safety message for vehicle drivers. Since vehicles are
mobile so they change their location frequently, therefore; robust
data delivery is a challenging task in the VANET. Due to
frequently network topology change characteristic, selection of a
routing protocol in VANET is challenging task. In this paper
performance of location-based routing protocols Directional-
Location Aided Routing (D-LAR), Location-Aided Routing (LAR)
and DIrectional Routing (DIR) are analyzed to decide best
routing protocol for VANET. LAR protocol limits the route
discovery area in the forward direction using GPS technology
and DIR protocol uses direction information from the baseline
drawn from the source and destination node. The D-LAR
protocol uses concepts of the both LAR and DIR protocols. Using
greedy forwarding approach D-LAR protocol selects next hop
forwarding node in the forward direction of the communication
range. Feasibility of D-LAR protocol has justified through
simulation in NS2 using routing metrics such as node distribution
at the border area of the communication range R, expected one
hop distance ࡱ൫ࡺ(, ࢘)൯ , expected hop counts E(H) between
source and destination node, expected delay E(delay), routing
overhead and packet loss. Through simulation work, it has shown
D-LAR protocol performs better as compared to LAR and DIR
protocol.
A Bandwidth Efficient Scheduling Framework for Non Real Time Applications in ...ijdpsjournal
The key concern on the bandwidth allocation and scheduling for non real time traffic are the fulfillment of its minimum throughput requirement and improvement of bandwidth utilization with acceptable delay. This paper proposes a simple and efficient scheduling framework for allocating bandwidth to non real time
polling service (nrtPS) users in IEEE 802.16 networks. In this framework, jointly selective repeat ARQ at the MAC layer and adaptive modulation and coding techniques at the physical are considered. Numerical simulations demonstrate that the proposed scheduling approach provides a graceful compromise between bandwidth utilization and packet delivery delay while maintaining the minimum throughput requirements of nrtPS applications. Thus proves the efficiency of the proposed framework. The simulation is done for unicast scenario.
EVALUATION OF (GPS/GLONASS) PATCH VERSUS RF GPS (L1) PATCHANTENNA PERFORMANCE...IJCSEA Journal
In any wireless communication network and system an antenna is an important element along the pathway and/or propagation path of an electrical signals. An addition, antenna module is a vital component of automated driving systems, it should function as needed in dGPS, HD map correction services, and radio and navigation systems. The main scope, objective and goal of this engineering research work involves the evaluation and determining the performance parameter and characteristic of the dual band (GPS/GLONASS) patch vs RF GPS L1(1.57542 GHz) passive patch antenna characteristic. FEKO simulation studies are carried out to extensively compare, make an assessment and evaluate the characteristic and performance parameter, such as the average gain and/or passive gain of the proposed antenna in the presence of background noise. Prior to the start of the FEKO simulation studies, a physical mechanical dimension measurements via a Digital instrumentation were conducted for the following: Radiating Element Size: The actual length (L), and width (W) Substrate Material Size: The substrate length (Lsub), width (Wsub), and height (h) The proposed antenna model for GPS only patch antenna operating at 1.57542 GHz and the GPS/GLONASS patch antenna resonating at 1.5925 GHz are developed. To be specific, this work presents the design, modeling, determining passive gain of the RF GPS L1 passive patch vs. active GPS/GLONAS Spatch antenna with intended targeted applications within the automotive system and space. Simulation are undertaken to generate the RF GPS L1 passive patch and active GPS/GLONASS patch antenna structure respectively for the sole purpose of evaluating the performance of the proposed GPS/GLONASS antenna. Simulation are performed rather than mathematical modeling. The two antennas are also compared from the size standpoint. The goal of this paper is to test, measure and evaluate the performance of GPS against GPS/GLONASS antennas. Another emphasis of this paper is how to obtain the equivalent amount of total passive gain in a GPS vs. that of GPS/GLONASS antenna
A Cooperative Localization Method based on V2I Communication and Distance Inf...IJCNCJournal
Relative positions are recent solutions to overcome the limited accuracy of GPS in urban environment. Vehicle positions obtained using V2I communication are more accurate because the known roadside unit (RSU) locations help predict errors in measurements over time. The accuracy of vehicle positions depends more on the number of RSUs; however, the high installation cost limits the use of this approach. It also depends on nonlinear localization nature. They were neglected in several research papers. In these studies, the accumulated errors increased with time due to the linearity localization problem. In the present study, a cooperative localization method based on V2I communication and distance information in vehicular networks is proposed for improving the estimates of vehicles’ initial positions. This method assumes that the virtual RSUs based on mobility measurements help reduce installation costs and facilitate in handling fault environments. The extended Kalman filter algorithm is a well-known estimator in nonlinear problem, but it requires well initial vehicle position vector and adaptive noise in measurements. Using the proposed method, vehicles’ initial positions can be estimated accurately. The experimental results confirm that the proposed method has superior accuracy than existing methods, giving a root mean square error of approximately 1 m. In addition, it is shown that virtual RSUs can assist in estimating initial positions in fault environments.
A COOPERATIVE LOCALIZATION METHOD BASED ON V2I COMMUNICATION AND DISTANCE INF...IJCNCJournal
Relative positions are recent solutions to overcome the limited accuracy of GPS in urban environment.
Vehicle positions obtained using V2I communication are more accurate because the known roadside unit
(RSU) locations help predict errors in measurements over time. The accuracy of vehicle positions depends
more on the number of RSUs; however, the high installation cost limits the use of this approach. It also
depends on nonlinear localization nature. They were neglected in several research papers. In these studies,
the accumulated errors increased with time due to the linearity localization problem. In the present study,
a cooperative localization method based on V2I communication and distance information in vehicular
networks is proposed for improving the estimates of vehicles’ initial positions. This method assumes that
the virtual RSUs based on mobility measurements help reduce installation costs and facilitate in handling
fault environments. The extended Kalman filter algorithm is a well-known estimator in nonlinear problem,
but it requires well initial vehicle position vector and adaptive noise in measurements. Using the proposed
method, vehicles’ initial positions can be estimated accurately. The experimental results confirm that the
proposed method has superior accuracy than existing methods, giving a root mean square error of
approximately 1 m. In addition, it is shown that virtual RSUs can assist in estimating initial positions in
fault environments.
A survey of ranging techniques for vehicle localization in intelligence tran...IJECEIAES
Observing the vehicles movement becomes an urgent necessity due to exponentially increasing numbers of vehicles in the world. However, to this regard, a good deal of research had been presented to estimate the exact physical position of the vehicle. The major challenges faced vehicle localization systems are large coverage areas required, positioning at diverse environments and positioning during a high-speed movement. However, in this paper, the challenges of employing the vehicle localization techniques, which rely on the propagation signal properties, are discussed. Moreover, a comparison between these techniques, in terms of accuracy, responsiveness, scalability, cost, and complexity, is conducted. The presented positioning technologies are classified into five categories: satellite based, radio frequency based, radio waves based, optical based, and sound based. The discussion shows that, both of satellite-based technology and cellular-based technology are emerge solutions to overcome the challenges of vehicle positioning. Satellite-based can provide a high accurate positioning in open outdoor environment, whereas the cellular-based can provide accurate and reliable vehicle localization in urban environment, it can support non-line of sight (NLOS) positioning and provide large coverage and high data transmission. The paper also shows that, the standalone localization technology still has limitations. Therefore, we discussed how the presented techniques are integrated to improve the positioning performance.
On the real time hardware implementation feasibility of joint radio resource ...IEEEFINALYEARPROJECTS
To Get any Project for CSE, IT ECE, EEE Contact Me @ 09849539085, 09966235788 or mail us - ieeefinalsemprojects@gmail.co¬m-Visit Our Website: www.finalyearprojects.org
A Modified Fault Tolerant Location-Based Service Discovery Protocol for Vehic...acijjournal
In the recent years, advances in Vehicular networks have attracted special attraction of researchers. Lately two types of applications have gain popularity: Road safety and Driving comfort. Reliable data transformation in the city environment is hard to accomplish due to presence of noise and obstacles. In
addition transient or permanent faults of vehicles or roadside routers (road components) are unavoidable, so we need a fault tolerant algorithm to overcome such failures. Although utilizing faulttolerant techniques cause to more efficiency and reliability in service discovery for vehicle networks, there are many few service discovery algorithms that have considered fault- tolerant techniques. In this paper we have improved one of these algorithms which is named Fault-Tolerant Location-Based
Vehicular Service Discovery Protocol (FLocVSD) in order to being more reliable.
International Journal of Computational Engineering Research (IJCER) ijceronline
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology
Performance Evaluation of GPSR Routing Protocol for VANETs using Bi-direction...CSCJournals
Routing in Vehicular Adhoc Networks is a challenging task where the nodes themselves are vehicles. The mobility factors such as beacon intervals and vehicles with different velocities may cause inaccuracy in the identification of the vehicle's position. This in turn affects the performance of the position based routing protocols. Further, there is a need to evaluate through simulations performance of the position based routing protocol, especially in urban realistic scenarios for VANETs. The work in this paper evaluates the performance of Greedy Perimeter Stateless Routing protocol (GPSR) for VANETs which is a popular position based protocol especially for routing in MANETs. In order to evaluate realistic simulation environment bi-directional coupling of OMNET++/ INET Framework and SUMO is chosen for Nagarbhavi region in Bengaluru, India. The simulations are done for various scenarios realizing the impact of mobility parameters on routing using GPSR, and performance is measured in terms of packet delivery ratio and throughput.
CROSS LAYER DESIGN APPROACH FOR EFFICIENT DATA DELIVERY BASED ON IEEE 802.11P...pijans
Intelligent Transportation Systems (ITS) have been one of the promising technology that has a great interest attention from many researchers over the world. Vehicular Ad-hoc Network (VANET) communications environment as a part of ITS opens the way for a wide range of applications such as safety applications, mobility and connectivity for both driver and passengers to exploit the transport systems in a smoothly, efficiently and safer way. Several challenging tasks facing adopting VANET functionality for ITS such as modelling of wireless transmission and routing issues. These research issues have become more critical due to the high mobility of vehicles nodes (transmitters and receivers) and unexpected network topology due to the high speed of nodes. In fact, modelling radio propagation channel in VANET environment which considers as one of a stringent communications environment is a challenging task. The selection of a suitable transmission model plays a key role in the routing decisions for VANET. Different propagation models allow calculating the Received Signal Strength (RSS) based on key environmental properties such as the distance between transmitter vehicle and a receiver vehicle, the gain and antenna height of transmitter and a receiver vehicles. Hence, it is useful to calculate RSS and SNR values for a specific propagation model and then these values can be used later for routing decision in order to find the best path with high SNR. This paper evaluates the performance of different transmission models (freespace, two-ray and log-normal) in terms of Receive Signal Strength (RSS). In addition, the performance of such wireless transmission models for vehicular communication in terms of PDR, throughput and delay is evaluated by applying the proposed cross layer routing approach based on IEEE 802.11p. By using MATLAB, the obtained results confirm the best packet delivery ratio for our proposed approach, where it indicates poor quality of DSSS PHY with high number vehicles. The minimum delay achieved when traffic density is decreased.
MECC scheduling algorithm in vehicular environment for uplink transmission in...IJECEIAES
Single Carrier Frequency Division Multiple Access (SC-FDMA) is chosen because of the lower peak-to-average power ratio (PAPR) value in uplink transmission. However, the contiguity constraint is one of the major constraint presents in uplink packet scheduling, where all RBs allocated to a single UE must be contiguous in the frequency-domain within each time slot to maintain its single carrier. This paper proposed an uplink-scheduling algorithm namely the Maximum Expansion with Contiguity Constraints (MECC) algorithm, which supports both the RT and NRT services. The MECC algorithm is deployed in two stages. In the first stage, the RBs are allocated fairly among the UEs. The second stage allocates the RBs with the highest metric value and expands the allocation on both sides of the matrix, M with respect to the contiguity constraint. The performance of the MECC algorithm was observed in terms of throughput, fairness, delay, and Packet Loss Ratio (PLR) for VoIP, video and best effort flows. The MECC scheduling algorithm is compared to other algorithms namely the Round Robin (RR), Channel-Dependent First Maximum Expansion (CD-FME), and Proportional Fairness First Maximum Expansion (PF-FME). From here, it can be concluded that the MECC algorithm shows the best results among other algorithms by delivering the highest throughput which is up to 81.29% and 90.04% than CD-FME and RR scheduler for RT and NRT traffic respectively, having low PLR and delay which is up to 93.92% and 56.22% of improvement than CD-FME for the RT traffic flow. The MECC also has a satisfactory level of fairness for the cell-edge users in a vehicular environment of LTE network.
An Improved Greedy Parameter Stateless Routing in Vehicular Ad Hoc NetworkIJAAS Team
Congestion problem and packet delivery related issues in the vehicular ad hoc network environment is a widely researched problem in recent years. Many network designers utilize various algorithms for the design of ad hoc networks and compare their results with the existing approaches. The design of efficient network protocol is a major challenge in vehicular ad hoc network which utilizes the value of GPS and other parameters associated with the vehicles. In this paper GPSR protocol is improved and compared with the existing GPSR protocol and AODV protocol on the basis of various performance parameters like throughput of the network, delay and packet delivery ratio. The results also validate the performance of the proposed approach.
International Journal of Engineering and Science Invention (IJESI)inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online
Joint Routing and Congestion Control in Multipath Channel based on Signal to ...IJECEIAES
Routing protocol and congestion control in Transmission Control Protocol (TCP) have important roles in wireless mobile network performance. In wireless communication, the stability of the path and successful data transmission will be influenced by the channel condition. This channel condition constraints come from path loss and the multipath channel fading. With these constraints, the algorithm in the routing protocol and congestion control is confronted with the uncertainty of connection quality and probability of successful packet transmission, respectively. It is important to investigate the reliability and robustness of routing protocol and congestion control algorithms in dealing with such situation. In this paper, we develop a detailed approach and analytical throughput performance with a cross layer scheme (CLS) between routing and congestion control mechanism based on signal to noise ratio (SNR) in Rician and Rayleigh as multipath fading channel. We proposed joint routing and congestion control TCP with a cross layer scheme model based on SNR (RTCP-SNR). We compare the performance of RTCP-SNR with conventional routing-TCP and routing-TCP that used CLS with routing aware (RTCP-RA) model. The analyses and the simulation results showed that RTCP-SNR in a multipath channel outperforms conventional routing-TCP and RTCP-RA.
Vehicular Ad-hoc Network (VANET) is a multi-hop
wireless ad-hoc network created by using mobile vehicles to
transmit safety message for vehicle drivers. Since vehicles are
mobile so they change their location frequently, therefore; robust
data delivery is a challenging task in the VANET. Due to
frequently network topology change characteristic, selection of a
routing protocol in VANET is challenging task. In this paper
performance of location-based routing protocols Directional-
Location Aided Routing (D-LAR), Location-Aided Routing (LAR)
and DIrectional Routing (DIR) are analyzed to decide best
routing protocol for VANET. LAR protocol limits the route
discovery area in the forward direction using GPS technology
and DIR protocol uses direction information from the baseline
drawn from the source and destination node. The D-LAR
protocol uses concepts of the both LAR and DIR protocols. Using
greedy forwarding approach D-LAR protocol selects next hop
forwarding node in the forward direction of the communication
range. Feasibility of D-LAR protocol has justified through
simulation in NS2 using routing metrics such as node distribution
at the border area of the communication range R, expected one
hop distance ࡱ൫ࡺ(, ࢘)൯ , expected hop counts E(H) between
source and destination node, expected delay E(delay), routing
overhead and packet loss. Through simulation work, it has shown
D-LAR protocol performs better as compared to LAR and DIR
protocol.
A Bandwidth Efficient Scheduling Framework for Non Real Time Applications in ...ijdpsjournal
The key concern on the bandwidth allocation and scheduling for non real time traffic are the fulfillment of its minimum throughput requirement and improvement of bandwidth utilization with acceptable delay. This paper proposes a simple and efficient scheduling framework for allocating bandwidth to non real time
polling service (nrtPS) users in IEEE 802.16 networks. In this framework, jointly selective repeat ARQ at the MAC layer and adaptive modulation and coding techniques at the physical are considered. Numerical simulations demonstrate that the proposed scheduling approach provides a graceful compromise between bandwidth utilization and packet delivery delay while maintaining the minimum throughput requirements of nrtPS applications. Thus proves the efficiency of the proposed framework. The simulation is done for unicast scenario.
EVALUATION OF (GPS/GLONASS) PATCH VERSUS RF GPS (L1) PATCHANTENNA PERFORMANCE...IJCSEA Journal
In any wireless communication network and system an antenna is an important element along the pathway and/or propagation path of an electrical signals. An addition, antenna module is a vital component of automated driving systems, it should function as needed in dGPS, HD map correction services, and radio and navigation systems. The main scope, objective and goal of this engineering research work involves the evaluation and determining the performance parameter and characteristic of the dual band (GPS/GLONASS) patch vs RF GPS L1(1.57542 GHz) passive patch antenna characteristic. FEKO simulation studies are carried out to extensively compare, make an assessment and evaluate the characteristic and performance parameter, such as the average gain and/or passive gain of the proposed antenna in the presence of background noise. Prior to the start of the FEKO simulation studies, a physical mechanical dimension measurements via a Digital instrumentation were conducted for the following: Radiating Element Size: The actual length (L), and width (W) Substrate Material Size: The substrate length (Lsub), width (Wsub), and height (h) The proposed antenna model for GPS only patch antenna operating at 1.57542 GHz and the GPS/GLONASS patch antenna resonating at 1.5925 GHz are developed. To be specific, this work presents the design, modeling, determining passive gain of the RF GPS L1 passive patch vs. active GPS/GLONAS Spatch antenna with intended targeted applications within the automotive system and space. Simulation are undertaken to generate the RF GPS L1 passive patch and active GPS/GLONASS patch antenna structure respectively for the sole purpose of evaluating the performance of the proposed GPS/GLONASS antenna. Simulation are performed rather than mathematical modeling. The two antennas are also compared from the size standpoint. The goal of this paper is to test, measure and evaluate the performance of GPS against GPS/GLONASS antennas. Another emphasis of this paper is how to obtain the equivalent amount of total passive gain in a GPS vs. that of GPS/GLONASS antenna
A Cooperative Localization Method based on V2I Communication and Distance Inf...IJCNCJournal
Relative positions are recent solutions to overcome the limited accuracy of GPS in urban environment. Vehicle positions obtained using V2I communication are more accurate because the known roadside unit (RSU) locations help predict errors in measurements over time. The accuracy of vehicle positions depends more on the number of RSUs; however, the high installation cost limits the use of this approach. It also depends on nonlinear localization nature. They were neglected in several research papers. In these studies, the accumulated errors increased with time due to the linearity localization problem. In the present study, a cooperative localization method based on V2I communication and distance information in vehicular networks is proposed for improving the estimates of vehicles’ initial positions. This method assumes that the virtual RSUs based on mobility measurements help reduce installation costs and facilitate in handling fault environments. The extended Kalman filter algorithm is a well-known estimator in nonlinear problem, but it requires well initial vehicle position vector and adaptive noise in measurements. Using the proposed method, vehicles’ initial positions can be estimated accurately. The experimental results confirm that the proposed method has superior accuracy than existing methods, giving a root mean square error of approximately 1 m. In addition, it is shown that virtual RSUs can assist in estimating initial positions in fault environments.
A COOPERATIVE LOCALIZATION METHOD BASED ON V2I COMMUNICATION AND DISTANCE INF...IJCNCJournal
Relative positions are recent solutions to overcome the limited accuracy of GPS in urban environment.
Vehicle positions obtained using V2I communication are more accurate because the known roadside unit
(RSU) locations help predict errors in measurements over time. The accuracy of vehicle positions depends
more on the number of RSUs; however, the high installation cost limits the use of this approach. It also
depends on nonlinear localization nature. They were neglected in several research papers. In these studies,
the accumulated errors increased with time due to the linearity localization problem. In the present study,
a cooperative localization method based on V2I communication and distance information in vehicular
networks is proposed for improving the estimates of vehicles’ initial positions. This method assumes that
the virtual RSUs based on mobility measurements help reduce installation costs and facilitate in handling
fault environments. The extended Kalman filter algorithm is a well-known estimator in nonlinear problem,
but it requires well initial vehicle position vector and adaptive noise in measurements. Using the proposed
method, vehicles’ initial positions can be estimated accurately. The experimental results confirm that the
proposed method has superior accuracy than existing methods, giving a root mean square error of
approximately 1 m. In addition, it is shown that virtual RSUs can assist in estimating initial positions in
fault environments.
A survey of ranging techniques for vehicle localization in intelligence tran...IJECEIAES
Observing the vehicles movement becomes an urgent necessity due to exponentially increasing numbers of vehicles in the world. However, to this regard, a good deal of research had been presented to estimate the exact physical position of the vehicle. The major challenges faced vehicle localization systems are large coverage areas required, positioning at diverse environments and positioning during a high-speed movement. However, in this paper, the challenges of employing the vehicle localization techniques, which rely on the propagation signal properties, are discussed. Moreover, a comparison between these techniques, in terms of accuracy, responsiveness, scalability, cost, and complexity, is conducted. The presented positioning technologies are classified into five categories: satellite based, radio frequency based, radio waves based, optical based, and sound based. The discussion shows that, both of satellite-based technology and cellular-based technology are emerge solutions to overcome the challenges of vehicle positioning. Satellite-based can provide a high accurate positioning in open outdoor environment, whereas the cellular-based can provide accurate and reliable vehicle localization in urban environment, it can support non-line of sight (NLOS) positioning and provide large coverage and high data transmission. The paper also shows that, the standalone localization technology still has limitations. Therefore, we discussed how the presented techniques are integrated to improve the positioning performance.
GPSFR: GPS-Free Routing Protocol for Vehicular Networks with Directional Ante...ijwmn
Efficient and practical communications between large numbers of vehicles are critical in providing high level of safety and convenience to drivers. Crucial real-time information on road hazard, traffic conditions and driver services must be communicated to vehicles rapidly even in adverse environments, such as “urban canyons” and tunnels. We propose a novel routing protocol in vehicular networks that does not require position information (e.g. from GPS) but instead rely on relative position that can be determined dynamically. This GPS-Free Geographic Routing (GPSFR) protocol uses the estimated relative position of vehicles and greedily chooses the best next hop neighbor based on a Balance Advance (BADV) metric which balances between proximity and link stability in order to improve routing performance. In this paper, we focuses primarily on the complexity of routing in highways and solves routing problems that arise when vehicles are near interchanges, curves, and merge or exit lanes of highways. Our simulation results show that by taking relative velocity into account, GPSFR reduces link breakage to only 27% that of GPSR in the dense network. Consequently, GPSFR outperforms GPSR in terms of higher data delivery ratio, lower delay, less sensitivity of the network density and route paths’length
ASSESSMENT OF ALTERNATIVE PRECISION POSITIONING SYSTEMSijitcs
The continuous evolution of technology, electronics, and software along with the dramatic decrease in the
cost of electronic devices has led to the spread of sensing, surveillance, and control devices. The Internetof-Things
(IoT) benefits from the spread of devices (things) by processing device feeds using Machine-toMachine
(M2M) technologies. At the heart of the M2M technologies lies the ability of devices (things) to identify their own location on the globe or relative to known landmark. Since location awareness is fundamental to processing sensing and control feeds, it has attracted researchers to identify ways to
identify and improve location accuracy. The article looks at Global Positioning Systems (GPS) along with the enhancements and amendments that apply to satellite based solutions. The article also looks at medium to short-range wireless solutions such as cellular, Wi-Fi, Dedicated Short-Range Communications (5.9 GHz DSRC) and similar solutions.
Cost Effective SMS Fire Approach for Transportation based on Vehicle Speediosrjce
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.
Predictive Data Dissemination in VanetDhruvMarothi
The vehicle itself is an information source that produces a large amount of various information including actual vehicle and environment sensors. The implementation of an efficient and scalable model for information dissemination in VANETs possesses major issues. In this dynamic environment, an ever-growing number of context dissemination messages are leveling up the usage of the channel which affects the network performance. This presentation tries to analyze and assess the key ideas of how to overcome the context data dissemination and how to reduce the amounts of transferred and stored data in a vehicular cooperation environment. This is one of the most prominent topics of pervasive computing.
Evaluation of CSSR with Direct TCH Assignment in Cellular NetworksIJERA Editor
Global System for Mobile communication (GSM) operators make use of Key Performance Indicators (KPIs) to appreciate the network performance and evaluate the Quality of Service (QoS) regarding end user perceived quality. KPIs are therefore becoming increasingly important in the context of network rollouts as well as within mature network optimization cycles. The performance of the mobile network is measured based on several counters describing the most important events over a measurement period. The KPIs are derived with the help of these counters using different formulations. Call Setup Success Rate (CSSR) is one of the most important KPIs used by all mobile operators. In Ouagadougou, Burkina-Faso, most of the active workers and remote area farmers rely largely on mobile communication services; the GPRS as data services remain highly competitive with GSM voice services. This paper presents a comparative evaluation of theoretically estimated CSSR to measured CSSR data on a real network with regard to GPRS services. The measured data was obtained from the Nokia Siemens Network (NSN) statistical tool. The results obtained showed significant improvements in areas where sharp drops in CSSR values were recorded for the measured CSSR. Significantly high R square values of close to 1 representing a high predictive ability from the regression analysis of the estimated CSSR were also recorded. It was concluded that the implementation of the CSSR formulation be extended to CSSR measurements to ensure increased subscriber satisfaction.
This note presents the potential avenues available for location monitoring and position estimation and through that the possibilities for vehicular traffic estimation in a Sri Lankan context.
The network and user equipment allow for location monitoring and position estimation through several methods made available through the 3GPP standards.
Novel Position Estimation using Differential Timing Information for Asynchron...IJCNCJournal
Positioning techniques have been a common objective since the early development of wireless networks. However, current positioning methods in cellular networks, for instance, are still primarily focused on the use of the Global Navigation Satellite System (GNSS), which has several limitations, like high power drainage and failure in indoor scenarios. This study introduces a novel approach employing standard LTE signaling in order to provide high accuracy positioning estimation. The proposed technique is designed in analogy to the human sound localization system, eliminating the need of having information from three spatially diverse Base Stations (BSs). This is inspired by the perfect human 3D sound localization with two ears. A field study is carried out in a dense urban city to verify the accuracy of the proposed technique, with more than 20 thousand measurement samples collected. The achieved positioning accuracy is meeting the latest Federal Communications Commission (FCC) requirements in the planner dimension.
NOVEL POSITION ESTIMATION USING DIFFERENTIAL TIMING INFORMATION FOR ASYNCHRON...IJCNCJournal
Positioning techniques have been a common objective since the early development of wireless networks. However, current positioning methods in cellular networks, for instance, are still primarily focused on the use of the Global Navigation Satellite System (GNSS), which has several limitations, like high power drainage and failure in indoor scenarios. This study introduces a novel approach employing standard LTE signaling in order to provide high accuracy positioning estimation. The proposed technique is designed in analogy to the human sound localization system, eliminating the need of having information from three spatially diverse Base Stations (BSs). This is inspired by the perfect human 3D sound localization with two ears. A field study is carried out in a dense urban city to verify the accuracy of the proposed technique, with more than 20 thousand measurement samples collected. The achieved positioning accuracy is meeting the latest Federal Communications Commission (FCC) requirements in the planner dimension.
PERFORMANCE ANALYSIS OF ROUTING PROTOCOLS WITH ROADSIDE UNIT INFRASTRUCTURE I...IJCNCJournal
Vehicular ad-hoc networks (VANETs) represent a powerful and active field of research and have given rise to many challenges related to routing protocols and communication problems with other vehicles or fixed infrastructure called roadside units (RSU). The dynamic topology and the obstacles encountered in VANET environments mean that the routing of data and the communication between vehicles is confronted with many problems, and particularly in vehicular applications that require reliable communication and satisfactory quality of service (QoS). This paper promotes the intention of infrastructure in an urban
scenario and studies the performance of routing protocols considering the constraint of mobility. This leads us to analyze a wide range of routing protocols to ensure optimal coverage and continuous connectivity, taking into consideration two types of data traffic in realistic environments that depend on certain performance metrics. The paper also investigates which protocols provide better performance with RSUs by ranking the results for QoS.
Similar to Ieeepro techno solutions 2013 ieee embedded project relative positioning enhancement (20)
Saudi Arabia stands as a titan in the global energy landscape, renowned for its abundant oil and gas resources. It's the largest exporter of petroleum and holds some of the world's most significant reserves. Let's delve into the top 10 oil and gas projects shaping Saudi Arabia's energy future in 2024.
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
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Hierarchical Digital Twin of a Naval Power SystemKerry Sado
A hierarchical digital twin of a Naval DC power system has been developed and experimentally verified. Similar to other state-of-the-art digital twins, this technology creates a digital replica of the physical system executed in real-time or faster, which can modify hardware controls. However, its advantage stems from distributing computational efforts by utilizing a hierarchical structure composed of lower-level digital twin blocks and a higher-level system digital twin. Each digital twin block is associated with a physical subsystem of the hardware and communicates with a singular system digital twin, which creates a system-level response. By extracting information from each level of the hierarchy, power system controls of the hardware were reconfigured autonomously. This hierarchical digital twin development offers several advantages over other digital twins, particularly in the field of naval power systems. The hierarchical structure allows for greater computational efficiency and scalability while the ability to autonomously reconfigure hardware controls offers increased flexibility and responsiveness. The hierarchical decomposition and models utilized were well aligned with the physical twin, as indicated by the maximum deviations between the developed digital twin hierarchy and the hardware.
Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two type of water scarcity. One is physical. The other is economic water scarcity.
2. 48 IEEE TRANSACTIONS ON INTELLIGENT TRANSPORTATION SYSTEMS, VOL. 14, NO. 1, MARCH 2013
However, multipath is a dominant error in urban areas and
cannot be removed using differential approaches [1]. In [21],
the method proposed is not experimentally verified, and the data
fusion algorithm employed may not be fast enough for real-time
positioning.
In this paper, avoiding radio ranging and range rating, a
CP method is proposed for relative positioning, which fuses
low-level GPS data, i.e., pseudoranges. In this method, GPS
pseudoranges are shared among the participating vehicles. Each
vehicle estimates its relative position to the neighbors fusing the
local GPS observations and those of the neighbors, which can
be received through vehicular communication. The idea behind
the proposed technique is similar to differential positioning
principles, but two more advantages are the main contributions
of this work, i.e.,
1) elimination of the infrastructure costs, which are required
for conventional systems such as DGPS;
2) achieving higher performance in relative positioning,
compared to DGPS by eliminating the errors induced by
infrastructure nodes.
Experimental results show about 37% and 45% improvement
over DGPS in the accuracy and precision of relative position-
ing, respectively.
In Section II, the problem and solution approach are ex-
plained. Section III investigates the performance of the adopted
approach to develop the CP technique. Section IV details the
estimator of the proposed CP method. In Section V, the exper-
imental results are discussed, the performance of the proposed
system is evaluated, and the viability of the proposed method is
verified. In Section VI, the nominated communication medium
is explained. Section VII summarizes the contributions of this
work and future steps.
II. PROBLEM DEFINITION AND SOLUTION APPROACH
Assume a number of vehicles in a VANET that have GPS
receivers and can communicate with each other. In addition,
assume that GPS signal coverage is sufficient in the area and
that the vehicles can observe at least four common GPS satel-
lites. This is a requirement for the proposed method and will be
detailed later. Due to this requirement, the proposed method is
not suitable for dense urban areas where the chance of observ-
ing four common satellites by the vehicles is low. The ultimate
goal is that each vehicle can estimate its relative position to
the neighbors using a data fusion algorithm that is fed by local
GPS observations and those of the neighbors received through
vehicle–vehicle communication. Two cases are explained and
compared. In one case, Fig. 1, we assume that there is a DGPS
reference station in the area. This station broadcasts DGPS
corrections, and vehicles estimate their absolute position using
GPS signals and DGPS corrections. Then, the vehicles com-
municate their absolute position estimates to other vehicles, so
that each vehicle can calculate its position relative to its neigh-
bors, differencing the absolute positions. We call this approach
DGPS-based relative positioning for the rest of this paper.
In the second case, i.e., our proposal, we assume that no
DGPS reference station and correction message is available (see
Fig. 2). The problem is to find a CP method that can provide
Fig. 1. Relative positioning using DGPS-based position estimates.
Fig. 2. Tight integration CP for relative positioning using low-level GPS data.
relative positioning among the vehicles using vehicle–vehicle
communication, without any infrastructure node. In addition,
the proposed method must perform better than case 1, i.e.,
DGPS-based relative positioning.
As will be explained later, this CP technique will be imple-
mented fusing low-level GPS data, pseudoranges, which are
shared among the vehicles. We call this a tight integration
CP. Each vehicle will use pseudorange data to estimate its
position relative to its neighbors. The proposed solution will
eliminate those GPS errors that are common for all vehicles in
the data fusion process. These errors are due to the ionosphere,
troposphere, GPS satellite orbit errors, and satellite clock drifts.
In DGPS, these errors are broadcast by reference stations as
correction messages. Then, each vehicle considers these correc-
tion messages to remove the common errors from the observed
pseudoranges and improve its standalone position estimates.
In [1], the pseudorange observable in a GPS receiver, which
is called node k, is explained as
ρi
k(t) = Ri
k(t) + cδk(t) + cδi
(t) + εi
(t) + ζi
k(t) (1)
where t is the time; ρi
k is the code pseudoranges between
node k and satellite i; Ri
k is the distance between node k
and satellite i; c is the speed of light; δk is the clock error of
receiver k; δi
is the clock error of satellite i; εi
is the error due
to ionosphere, troposphere, and orbit of satellite i; and ζi
k is
3. ALAM et al.: RELATIVE POSITIONING ENHANCEMENT IN VANETs: A TIGHT INTEGRATION APPROACH 49
Fig. 3. Relative geometry of two vehicles and two satellites.
the effect of thermal noise in receiver k and multipath error
of satellite i. In (1), the satellite clock error is the same for
all receivers. The error from the ionosphere, troposphere, and
satellite orbit is also the same for all receivers in a vicinity of
tens of kilometers [1]. These errors can be eliminated through
differencing the observations of any pair of GPS receivers k
and l, which observe a common satellite. The clock error of the
receivers can also be removed if two common satellites can be
observed by the receivers. Double differencing is a technique
for removing the receivers’ clock errors and correlated errors of
the GPS observations by two receivers and two satellites. In [3],
the double differencing operation for observation X in nodes k
and l from satellites i and j is defined as follows:
Xij
kl(t) = Xi
k(t) − Xi
l (t) − Xj
k(t) + Xj
l (t). (2)
Substituting (1) in (2), the double difference of the pseudor-
anges for nodes k and l and satellites i and j at time t is
ρij
kl(t) = Rij
kl(t) + ζij
kl(t). (3)
As can be seen, the correlated errors between two nodes, the
clock error of the receivers, and the clock error of the satellites
are eliminated in (3). The pseudorange double difference is
equal to that of ranges to satellites plus the effect of uncorre-
lated errors, which cannot be removed by differencing. Double
differencing can be used for relative positioning. For example,
in RTK GPS, the double difference of GPS carrier phases
is used for precise positioning [3]. Of course, this method
cannot yet be deployed for vehicular positioning due to the
vulnerability of phase measurements to the high dynamics of
vehicles and frequent signal blockage and multipath in urban
areas. Another example is the method proposed in [22], which
uses a combination of double differenced pseudoranges and
carrier phases for relative positioning between two airplanes for
collision avoidance purposes. For our problem, we try to find
relative position estimates between the vehicles using (3). The
left side of (3) is formed based on observed pseudoranges. In
the right side, ζij
kl is the residual of uncorrelated errors that are
not removed by double differencing. This will be treated as ob-
servation noise. For relative positioning, Rij
kl should be decom-
posed in terms of relative positions between the receivers. Fig. 3
shows two vehicles, i.e., k and l, and a pair of satellites i and j.
In this figure, ui is the unit vector from node k (or l) to
satellite i, and uj is the unit vector from node k (or l) to satellite
j. Assuming that rk and rl are the position vectors of vehicles k
and l, respectively, rkl = rl − rk is the relative position vector
between node k and node l. As explained in [3], due to the
very long distance between the satellites and earth, the relative
vectors between vehicles and each satellite can be assumed
to be parallel. In addition, the unit vector to each satellite is
effectively the same for all vehicles in a vicinity of tens of
kilometers due to the long distance between the satellites and
the vehicles (more than 20 000 km). We have
Ri
k − Ri
l = uT
i rkl
Rj
k − Rj
l = uT
j rkl
(4)
where T is the transpose operator. Considering (2) and (4), the
double difference of the distances between the vehicles and
satellites is
Rij
kl(t) = [ui(t) − uj(t)]T
rkl(t). (5)
Substituting (5) in (3) leads to
ρij
kl(t) = [ui(t) − uj(t)]T
rkl(t) + ζij
kl(t). (6)
In (6), for each node, the left side is known from local ob-
servations and received data through vehicular communication.
The unknown relative position and the observation noise are
in the right side. The unit vectors can be accurately calculated
using the standalone GPS-based position estimates because unit
vectors are effectively the same for all points in the vicinity of
the vehicles, due to the great distance to the satellites. For a 3-D
solution, three incidences of equation are required to estimate
relative position between vehicles k and l, i.e., rkl. Before pre-
senting the detailed design of the CP technique, a performance
analysis is discussed in Section III. This analysis is indepen-
dent of the proposed CP method and investigates the potential
achievable performance adopting the tight integration approach
and that of DGPS. The results of this analysis also provide
insights into the design of the tight integration CP algorithm.
III. GENERAL PERFORMANCE ANALYSIS
To analyze and compare the performances of the adopted
solution approach and DGPS, the Cramer–Rao Lower Bound
(CRLB) [23] of these methods is investigated. CRLB is the
best achievable covariance of error by an unbiased estimator.
The comparison of the CRLBs helps predict which technique
will perform better. We expect experimental results to comply
with CRLB analysis. CRLB is the inverse of Fisher Information
Matrix (FIM) [23]. The FIM is calculated as
IZ(θ) = E
∂ ln (p(Z|θ))
∂θ
T
∂ ln (p(Z|θ))
∂θ
θ (7)
where Z is the observation vector of a system; θ is the state
vector of that system; p is the conditional probability density
function (pdf) of Z, conditional on the value of θ; and E{·} is
the expected value operator.
A. CRLB of the Tight Integration Approach
To calculate the CRLB, we consider a general condition with
m common visible satellites and n vehicles, which broadcast
their observed GPS pseudoranges. Thus, each vehicle can
4. 50 IEEE TRANSACTIONS ON INTELLIGENT TRANSPORTATION SYSTEMS, VOL. 14, NO. 1, MARCH 2013
fuse its observed pseudoranges and those of n − 1 neigh-
bors received through vehicular communication. Assuming that
vehicle 1 is the target vehicle and performs CP to estimate its
relative position to all neighbors
θn = [ rT
12 · · · rT
1n ]T
(8)
Zn = [ ρ12
12 · · · ρ1m
12 · · · ρ12
1n · · · ρ1m
1n ]T
(9)
ζn = [ ζ12
12 · · · ζ1m
12 · · · ζ12
1n · · · ζ1m
1n ]T
(10)
are the state, observation, and noise vectors, respectively, and
we have
Zn = Hnθn + ζn (11)
where
Hn =
⎡
⎢
⎢
⎣
U O · · · · · · O
O U O · · · O
...
...
...
...
...
O · · · · · · O U
⎤
⎥
⎥
⎦
(m−1)(n−1)×3(n−1)
(12)
U(t) =
⎡
⎢
⎢
⎣
uT
1 (t) − uT
2 (t)
uT
1 (t) − uT
3 (t)
...
uT
1 (t) − uT
m(t)
⎤
⎥
⎥
⎦ (13)
and O is a (m − 1) × 3 zero matrix. To calculate p(Zn|θn),
the covariance of Zn is required. Equation (11) can be refor-
mulated as
Zn = Hnθn + An
ˆζn (14)
where
ˆζn = [ ζ1
1 · · · ζm
1 · · · ζ1
n · · · ζm
n ]T
(15)
An =
⎡
⎢
⎢
⎣
A −A O · · · · · · O
A O −A O · · · O
...
...
...
...
...
...
A O · · · · · · O −A
⎤
⎥
⎥
⎦
(m−1)(n−1)×mn
(16)
with O being a (m − 1) × m zero matrix, and
A = [ 1(m−1)×1 −I(m−1)×(m−1) ] . (17)
1 in A represents a matrix with subscripted dimensions and
all entries being 1. Assuming independence of the error of
observed pseudoranges and σρ as the standard deviation (STD)
of pseudorange errors, the covariance of Zn is
n = σ2
ρAnAT
n . (18)
Assuming a Gaussian pdf for pseudorange errors, we have
p(Zn|θn) =
exp −1
2 (Zn −Hnθn)T −1
n (Zn −Hnθn)
(2π)(m−1)(n−1)/2 det( n)
. (19)
Substituting (19) in (7) and simplifying, FIM and CRLB are
represented by
IZn = HT
n
−1
n Hn (20)
CCP = I−1
Zn = HT
n
−1
n Hn
−1
(21)
respectively. Equation (21) represents the CRLB of the pro-
posed CP system with n participating vehicles. Considering
(12) and (18), it can be concluded that CRLB is a function of
pseudorange errors and location of the visible satellites.
B. CRLB of DGPS-Based Relative Positioning
DGPS-based relative positioning (Fig. 1) is conducted by
each vehicle subtracting its DGPS-based absolute position esti-
mate and that of a neighbor that is received through vehicular
communication. Thus, the CRLB of the DGPS-based absolute
positioning is considered first. For vehicle k, the state vector
can be defined as
θk = [ rk cδk ] (22)
where rk is the absolute position vector, and δk is the clock error
of the vehicle. According to [1], using the Taylor expansion,
the vector of the observed pseudoranges by vehicle k can be
presented in linear form, i.e.,
Zk = H θk + ζk (23)
where
Zk = [ ρ1
k · · · ρm
k ]T
(24)
H =
⎡
⎢
⎣
uT
1 1
...
...
uT
m 1
⎤
⎥
⎦ (25)
ζk = [ ζ1
k · · · ζm
k ]T
. (26)
For DGPS, we assume that common errors have already
been removed from the pseudorange observations (24). Thus,
the observation noise (26) includes uncorrelated errors such
as multipath and receiver noise, which cannot be removed
by DGPS [1]. Common errors among the receivers lead to
bias in position estimates. Thus, σρ can be considered as the
STD of the uncorrelated errors of pseudoranges at the DGPS
base station and DGPS receiver, and the STD of the corrected
pseudoranges at the DGPS receiver is
√
2σρ. Considering this
and assuming a Gaussian distribution for errors, the conditional
pdf of observation is
p (Zk|θk) =
exp − 1
4σ2
ρ
(Zk − H θk)T
(Zn − Hnθn)
2
√
πσρ
.
(27)
Substituting (27) in (7) and simplifying
Ik =
1
2σ2
ρ
(H T
H )−1
(28)
Ck = 2σ2
ρH T
H (29)
represent the FIM and CRLB of the DGPS-based absolute
position estimates of vehicle k, respectively.
As mentioned before, vehicle k calculates the relative po-
sition to vehicle l by differencing its DGPS-based absolute
position and that of vehicle l. Thus, due to the independence
5. ALAM et al.: RELATIVE POSITIONING ENHANCEMENT IN VANETs: A TIGHT INTEGRATION APPROACH 51
Fig. 4. Performance of the tight integration approach over 24 hours.
of positioning errors of different vehicles, the CRLB of DGPS-
based relative positioning is
CDGPS = 2Ck = 4σ2
ρH T
H . (30)
Now, (21) and (30) can be used to analyze and compare the
performance of the proposed CP approach and DGPS-based
relative positioning.
C. Evaluation of CRLBs
To investigate performance, the visible GPS satellites in
the vicinity of the test area are monitored using data logged
by the GNSS base station at the University of New South
Wales (UNSW), Sydney, Australia. The number of visible GPS
satellites at the base station varies between 7 and 12 over
24 hours. For calculating the performance based on CRLB, the
following distance root mean square (drms) error parameters
are defined for the tight integration approach and DGPS-based
relative positioning, respectively:
TIdrms = CCP(1, 1) + CCP(2, 2) (31)
DGPSdrms = CDGPS(1, 1) + CDGPS(2, 2). (32)
First, using the data logged at the UNSW GNSS base station,
the performance of the tight integration approach is calculated
over 24 hours for different numbers of common visible GPS
satellites m. When there is more than one possible combina-
tion of GPS satellites, the average of the performance from
different combinations is considered. For now, the number of
participating vehicles is assumed to be n = 10, which is an
arbitrary number. In addition, the STD of pseudorange errors
is considered to be σρ = 3 m. This value is set with regard to
the observations by the GPS receivers used for the experiments,
when located in a fixed known position. Fig. 4 shows the
behavior of TIdrms.
As can be seen, the performance increases for higher num-
bers of common visible satellites. In addition, the performance
fluctuates over time due to varying positions of the satellites.
Before comparing with DGPS, the effect of the number of
Fig. 5. Performance of the tight integration approach for different numbers of
vehicles.
participating vehicles in the tight integration approach is inves-
tigated. For this, n is varied between 2 and 20, and for each
condition, the average of TIdrms over 24 hours is considered.
σρ = 3 m is considered as previously given. Fig. 5 shows
the performance for different numbers of vehicles and visible
satellites. As can be seen, the performance is independent of
the number of participating vehicles. This behavior is different
from the general attitude of range or range-rate-based CP
systems in which increasing the number of vehicles improves
the performance [24].
The reason is the lack of intervehicle range or range-rate data.
In range/range-rate-based CP techniques, adding one vehicle to
the system is equivalent to adding one set of GNSS data (for
the case that GNSS is available) plus some range or range-rate
data between the added vehicle and its neighbors. However,
in the proposed tight integration approach, adding a vehicle
to the system only adds a set of GNSS data with relevant
uncertainties. Here, we conclude that the target vehicle in the
proposed tight integration approach can manage to optimize the
computational burden of CP. The target vehicle receives GPS
pseudorange data from the neighbors. Due to the independence
of the performance from the number of neighbors, the target
vehicle has different choices to fuse data. It can form several
parallel CP engines for each neighbor. This results in matrixes
with low dimensions and low computational burden for each
engine. However, the number of parallel CP engines increases.
Another strategy is to form a single CP engine for all neighbors,
which results in big matrixes and higher computational burden.
A combined approach is also possible to divide the neighbors
among a certain number of CP engines. Investigating more de-
tails of this issue is not of interest in this paper. It is considered
to be future work. However, we adopt the first approach to
develop our CP algorithm, which is considering each neighbor
in a separate CP engine.
Now, considering two vehicles for CP, the expected per-
formance of the tight integration approach and DGPS-based
relative positioning is investigated. For this, the relevant pa-
rameters defined by (31) and (32) are calculated for n = 2 and
different numbers of visible satellites. σρ = 3 m is considered
6. 52 IEEE TRANSACTIONS ON INTELLIGENT TRANSPORTATION SYSTEMS, VOL. 14, NO. 1, MARCH 2013
Fig. 6. Performance of (left) the tight integration approach and (right) DGPS-
based relative positioning.
TABLE I
AVERAGE PERFORMANCE OVER 24 HOURS
as previously given. Fig. 6 shows the results. As can be seen, the
tight integration approach shows an improvement over DGPS-
based relative positioning. This is generally sensible because
the uncorrelated errors of the receivers are not removed through
differencing. In DGPS-based relative positioning, these errors
enter the system from three receivers (i.e., two vehicles and one
base), whereas, for the proposed method, there are only two
receivers.
Table I summarizes the average drms for two approaches and
different numbers of satellites and relative improvement over
DGPS using
μCRLB = 1 −
Avg. TIdrms
Avg. DGPSdrms
× 100. (33)
According to Table I, we can expect about 30% improvement
over DGPS using the tight integration approach when the
number of common visible satellites is more than 4.
IV. TIGHT INTEGRATION COOPERATIVE
POSITIONING TECHNIQUE
In Section II, a tight integration approach based on double
differences was proposed. A general performance analysis was
conducted in Section III to illustrate the superiority of tight
integration over DGPS for relative positioning.
In this section, an estimator is explained for tight integration
CP for relative positioning between the vehicles. Equation (6)
relates the relative position of two vehicles to double differ-
ences of observed GPS pseudoranges. Considering the results
of the previous section, here we assume that the target vehicle
forms a separate CP engine for each neighbor. To estimate the
relative position of a neighbor, a Kalman filter is considered for
the process and observation models, as presented in
θ(t + τ) = Fθ(t) + Gγγ(t) (34)
Z(t) = H(t)θ(t) + ζ(t) (35)
respectively, where τ is the observation period, θ is the state
vector, F is the state transition model, Gγ is the process noise
model, γ is the Gaussian relative acceleration noise with the
STD σγ and zero mean along each axis, Z(t) is the observation
vector, H(t) is the observation model, and ζ is the observation
noise. Assuming vehicle k to be the target vehicle, the state
vector for relative positioning to vehicle l is defined as
θ(t) =
rkl(t)
vkl(t)
(36)
where vkl is the relative velocity between the vehicles. This
definition leads to
F =
I3×3 τI3×3
O3×3 I3×3
, Gγ =
0. 5τ2
I3×3
τI3×3
(37)
where O is a matrix with all zero entries, and I is the identity
matrix. The process noise covariance Q is
Q = σ2
γGγGT
γ = σ2
γ
0. 25τ4
I3×3 0. 5τ3
I3×3
0. 5τ3
I3×3 τ2
I3×3
. (38)
Assuming that a normal condition for driving (no skidding,
no severe shaking, etc.) σγ is considered to be of low value
0.1 m/s2
, for the proposed method, the observation vector for
m common visible satellites is
Z(t) = [ ρ12
kl (t) · · · ρ1m
kl (t) ]T
(39)
and according to (35) and (6), there is
H(t) = [ U(t) O(m−1)×3 ] (40)
and the observation noise is
ζ(t) = [ ζ12
kl (t) · · · ζ1m
kl (t) ]T
. (41)
To calculate the covariance of the observation noise, (41) is
reformulated as
ζ = [ A −A ] [ ζ1
k · · · ζm
k ζ1
l · · · ζm
l ]T
. (42)
Assuming the independence of pseudorange errors, there is
= [ A −A ][ A −A ]T
σ2
ρ (43)
which leads to
= 2σ2
ρAAT
. (44)
The value of σρ can be estimated based on the measurements
when the receiver antenna is located in a known position.
Provided at least four common satellites are visible at nodes
k and l, the initial state of the system can be estimated using
(6). Having F, Gγ, H, , and Q, the required parameters for
7. ALAM et al.: RELATIVE POSITIONING ENHANCEMENT IN VANETs: A TIGHT INTEGRATION APPROACH 53
Fig. 7. Test site and path (original photo from Google Map).
Kalman filtering are provided and the observations (39) can be
fed to the filter for relative positioning.
The performance of the proposed method will be compared
with that of DGPS-based relative positioning. DGPS-based
relative position estimate is the difference of the DGPS-based
absolute position of the target vehicle and that of its neighbor.
To calculate DGPS absolute position estimates, a standard
method, using a Kalman filter, will be used after applying the
DGPS corrections to the observed pseudoranges [1]. The DGPS
Corrections are calculated using the observations of the GNSS
base station at UNSW.
V. EXPERIMENTAL RESULTS
To evaluate the presented CP method, a test case was set
up including two vehicles equipped with single-band GPS re-
ceivers (i.e., one NordNav and one u-blox AEK-4T) and laptops
for data logging. The vehicles were driven along different roads
near UNSW with different speeds and sufficient GPS satellite
coverage for about 45 min. The pseudoranges and correspond-
ing GPS time tags observed by the receivers were logged during
the experiment. For evaluation purposes, the real position of the
vehicles, with cm level of accuracy, was logged using a Leica
1200 RTK GPS rover in each vehicle. The performance of RTK
GPS is limited by the high mobility of vehicles, particularly
in urban areas. Because of this, the more accurate position of
the vehicles was not logged for the whole 45 min. The longest
continuous useful observation time with RTK GPS fixes was
12 min, and this is used to evaluate the proposed method. Fig. 7
shows the test site and the corresponding route traveled during
12 min.
As can be seen, the route includes a combination of straight
and curvy sections to improve the credibility of the evaluation
of the proposed system. The UNSW base station is located in
this figure. This station continuously logs the GNSS observa-
tions. Its observations during our test are used to provide DGPS
corrections.
The vehicles were driven at different speeds, relative speeds,
and distances. The maximum speed was 80 km/h, the maximum
relative speed was 34 km/h, and the maximum distance between
them was 78 m. Fig. 8 shows the number of observed GPS satel-
lites at each vehicle during the test. At the UNSW base station,
the signals from the highest possible number of visible satellites
(11 or 12 satellites) in the area were acquired. As can be seen,
Fig. 8. Number of observed GPS satellites by the vehicles.
Fig. 9. Relative positioning error for CP and DGPS.
the GPS receiver in vehicle 1 has better performance in acquir-
ing the satellites. For short-term lost signals, 1 to 2 epochs,
the corresponding innovation in the Kalman filter is set to zero,
and the relevant entry of the observation covariance is set to
a very large number to represent mathematical infinity.
To evaluate the performance of the proposed CP method, the
error of position estimates is defined as
er(t) = ˆrkl(t) − rkl(t) (45)
where ˆrkl is the estimated relative position. This error is calcu-
lated for the proposed method and DGPS. The root mean square
(rms) and STD of er is used to define the achieved improvement
over DGPS, i.e.,
μa = 1 −
RMS(er|CP)
RMS(er|DGPS)
× 100 (46)
μp = 1 −
STD(er|CP)
STD(er|DGPS)
× 100. (47)
Parameter μa indicates the improvement in bias of the error
(accuracy), and μp shows the enhancement in the noise of error
(precision). Fig. 9 compares the performance of the proposed
CP method with that of DGPS. Table II summarizes all results.
As can be seen, the proposed CP method outperforms DGPS.
In addition, the performance achieved for each method and
8. 54 IEEE TRANSACTIONS ON INTELLIGENT TRANSPORTATION SYSTEMS, VOL. 14, NO. 1, MARCH 2013
TABLE II
EXPERIMENTAL RESULTS (CP AND STANDALONE AND DGPS ERRORS)
Fig. 10. Relative positioning error and speed.
improvement complies with the results of Section III. Another
point is important here. The performance of DGPS is not
on the order of submeters in the vehicular environment of
this experiment. This is due to considerable multipath error
in vehicular and urban areas and receiver noise that are not
removed through differencing.
Now, the impact of the speed of the vehicles on the perfor-
mance of positioning is investigated. To do this, the positioning
error is characterized for different absolute and relative speeds.
For this, the range between the minimum and maximum of
absolute and relative speeds are divided into ten speed bins. The
average of relative positioning error is calculated for each bin.
For absolute speed, the average of the speeds of the two vehicles
at each time is considered. Fig. 10 shows the effect of speed on
the performance.
As can be seen, the error of the proposed method and
that of DGPS is lower at high and low speeds. The reason
is that, at high speeds, the vehicles have been in highways
without surrounding buildings. Thus, multipath error is lower.
In addition, the difference of performances decreases for higher
speeds. The very low speeds belong to a top floor open space car
park without surrounding obstacles. This situation results in low
multipath as well. The middle speeds belong to urban streets
with some buildings and trees around. Thus, the multipath
error is higher. For relative speed, the error increases at higher
relative speeds. Higher relative speed is for the urban streets
where the pattern of speed in two vehicles is independent due
to traffic conditions and stopping at traffic lights. However, on
highways, both vehicles had a similar speed around the average
speed of the traffic.
VI. COMMUNICATION AND COMPUTATION
The assumed medium for vehicular communication is ded-
icated short range communication (DSRC) [25]. DSRC is a
medium with 75-MHz bandwidth, at 5.9 GHz, as described
in the IEEE802.11p standard, which is dedicated to vehicle–
vehicle and vehicle–infrastructure communication. The nomi-
nal communication range is about 1000 m under line-of-sight
conditions. DSRC has basically seven channels, each with
10-MHz bandwidth. It is assumed that one of these channels
can be used for the presented CP method and vehicles share
their GPS-based data, communicating through that channel.
In the proposed CP algorithm, the bandwidth of DSRC is
not a concern because the considered broadcast data, i.e., the
pseudoranges of the visible satellites, need a bandwidth that is
much lower than the bandwidth of DSRC channels (10 MHz),
even if the update rate is a few per second. For instance,
with regard to [26], less than 150 bytes of data is required to
transmit the pseudoranges and carrier phases of ten satellites
observed by a dual-band receiver. The required data rate for
the proposed method is less than this, as only a single band is
used for the proposed technique, and the GPS carrier phase is
not communicated. Moreover, according to [27], the maximum
number of neighbors in the DSRC range in typical moving
heavy traffic is about 35. Thus, considering the necessary data
rate for each vehicle to run the proposed CP method, it seems
that DSRC bandwidth is far beyond the requirements of the
international standard for GNSS real-time data exchange.
The computational burden of the proposed method is not a
challenge for implementation. The double difference approach
provides a linear state-space model, and there is no iterative
step, such as absolute positioning, to estimate the relative
position. The process of relative position estimation does not
depend on communication after the vehicle receives a packet
from its neighbor. This means that, after receiving a packet from
a neighbor, the CP algorithm can be locally run and can estimate
the relative position within a known period.
VII. CONCLUSION
A CP method has been presented for relative positioning in
VANETs adopting a tight integration approach. The method is
based on fusing low-level GPS data, i.e., pseudoranges, from
the participating vehicles. The system is functional with at
least four common visible satellites for the vehicles. Apply-
ing real logged data from a vehicular field test, the achieved
enhancement in the accuracy and precision of relative position-
ing over DGPS is about 37% and 45%, respectively.
Another advantage of the proposed technique, compared
with the majority of vehicular CP methods, is the independence
of intervehicle radio ranging methods such as RSS, TOA, and
TDOA. These methods are very problematic in VANETs and
not as accurate as assumed in the literature.
Multipath error degrades the performance of the conven-
tional differential positioning methods, e.g., DGPS. Although
the proposed method has a differential approach in principle,
eliminating the reference station, which is required to broadcast
corrections for DGPS, was a key factor for superiority of the
proposed method over DGPS-based relative positioning.
Regarding a typical maximum number of the possible neigh-
bors for a vehicle in VANET and the required data rate for
GNSS data exchange, it is concluded that the bandwidth of a
DSRC channel is enough for the proposed system.
9. ALAM et al.: RELATIVE POSITIONING ENHANCEMENT IN VANETs: A TIGHT INTEGRATION APPROACH 55
The performance of the proposed method does not depend on
the number of participating vehicles. Thus, the computational
burden of the proposed method can be optimized by managing
the number of CP engines and the neighbors processed at each
engine. This will be considered as future work.
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Nima Alam received the B.E. degree in telecommu-
nication systems and the M.Eng.Sc. degree in con-
trol systems from Sharif University of Technology,
Tehran, Iran, in 1998 and 2000, respectively, and the
Ph.D. degree in vehicular positioning enhancement
using dedicated short-range communication from the
University of New South Wales (UNSW), Sydney,
Australia, in 2012.
He is currently a Research Associate with the
Australian Centre for Space Engineering Research,
UNSW. From 2000 to 2008, he was involved in a
variety of projects in the automotive industry, including industrial robotics,
automated guide vehicles, factory automation, machine vision, and Global
Positioning System navigation. In 2010 and 2011, he was a Consultant with
the National ICT Australia TruckOn project and Future Logistics Living
Laboratory.
Asghar Tabatabaei Balaei received the B.E. and
M.Eng.Sc. degrees in electrical engineering from
Sharif University of Technology, Tehran, Iran, in
1997 and 2000, respectively, and the Ph.D. degree
in global navigation satellite interference from the
University of New South Wales (UNSW), Sydney,
Australia, in 2008.
He has been a Postdoctoral Research Fellow with
the School of Surveying and Spatial Information
Systems, UNSW, working in the area of cooperative
positioning systems. He is currently an Associate
Lecturer with the Department of Electrical Engineering and Telecommunica-
tion, UNSW, as well as a Researcher with the National ICT Australia.
Andrew G. Dempster (M’92–SM’03) received the
B.E. and M.Eng.Sc. degrees from the University of
New South Wales (UNSW), Sydney, Australia, in
1984 and 1992, respectively, and the Ph.D. degree
in efficient circuits for signal processing arithmetic
from the University of Cambridge, Cambridge, U.K.,
in 1995.
He is currently the Director of the Australian
Centre for Space Engineering Research, UNSW. He
is also the Director of Research with the School of
Surveying and Spatial Information Systems and the
Director of Postgraduate Research of the Faculty of Engineering. He is the
holder of six patents. His current research interests are satellite navigation
receiver design and signal processing, as well as new location technologies.
Dr. Dempster was a System Engineer and Project Manager for the first Global
Positioning System receiver developed in Australia in the late 1980s and has
been involved in satellite navigation ever since.