VANET: Performance Comparison of BNGF Method in Different Vehicular Traffic Scenarios

A Vehicular Ad hoc Network (VANET) is a wireless ad hoc network that is formed between vehicles on an on demand basis. A lot of research work around the world is being conducted to design the routing protocols for VANETs. In this paper, we examine the significance Greedy Forwarding with Border Node based approach for VANETs to optimize path length between vehicles in different traffic scenarios. This protocol is called Border Node Greedy Forwarding (BNGF) since it uses border nodes with Greedy Forwarding. We categorize BNGF as BNGF-H for highway and BNGF-C for city traffic scenarios. We have simulated this protocol using NS-2 simulator and calculated the performance in terms of end-to-end delay and packet delivery ratio. We compare both the methods for highway and city traffic scenarios. The result clearly show that the end-to-end delay for BNGF-C is significantly lower and packet delivery ratio is higher than BNGF-H

Enabling Accurate Cross-Layer PHY/MAC/NET Simulation Studies of Vehicular Communication Networks

Vehicle-to-vehicle and vehicle-to-roadside communications is required for numerous applications that aim at improving traffic safety and efficiency. In this setting, however, gauging system performance through field trials can be very expensive especially when the number of studied vehicles is high. Therefore, many existing studies have been conducted using either network or physical layer simulators; both approaches are problematic. Network simulators typically abstract physical layer details (coding, modulation, radio channels, receiver algorithms, etc.) while physical layer ones do not consider overall network characteristics (topology, network traffic types, and so on). In particular, network simulators view a transmitted frame as an indivisible unit, which leads to several limitations. First, the impact of the vehicular radio channel is typically not reflected in its appropriate context. Further, interference due to frame collisions is not modeled accurately ( if at all) and, finally, the benefits of advanced signal processing techniques, such as interference cancellation, are difficult to assess. To overcome these shortcomings we have integrated a detailed physical layer simulator into the popular NS-3 network simulator. This approach aims to bridge the gap between the physical and network layer perspectives, allow for more accurate channel and physical layer models, and enable studies on cross-layer optimization. In this paper, we exemplify our approach by integrating an IEEE 802.11a and p physical layer simulator with NS-3. Further, we validate the augmented NS-3 simulator against an actual IEEE 802.11 wireless testbed and illustrate the additional value of this integration

CAMA: Efficient Modeling of the Capture Effect for Low Power Wireless Networks

Network simulation is an essential tool for the design and evaluation of wireless network protocols, and realistic channel modeling is essential for meaningful analysis. Recently, several network protocols have demonstrated substantial network performance improvements by exploiting the capture effect, but existing models of the capture effect are still not adequate for protocol simulation and analysis. Physical-level models that calculate the signal-to-interference-plus-noise ratio (SINR) for every incoming bit are too slow to be used for large-scale or long-term networking experiments, and link-level models such as those currently used by the NS2 simulator do not accurately predict protocol performance. In this article, we propose a new technique called the capture modeling algorithm (CAMA) that provides the simulation fidelity of physical-level models while achieving the simulation time of link-level models. We confirm the validity of CAMA through comparison with the empirical traces of the experiments conducted by various numbers of CC1000 and CC2420-based nodes in different scenarios. Our results indicate that CAMA can accurately predict the packet reception, corruption, and collision detection rates of real radios, while existing models currently used by the NS2 simulator produce substantial prediction error

Scalable Map Information Dissemination for Connected and Automated Vehicle Systems

Situational awareness in connected and automated vehicle (CAV) systems becomes particularly challenging in the presence of non-line of sight objects and/or objects beyond the sensing range of local onboard sensors. Despite the fact that fully autonomous driving requires the use of multiple redundant sensor systems, primarily including camera, radar, and LiDAR, the non-line of sight object detection problem still persists due to the inherent limitations of those sensing techniques. To tackle this challenge, the inter-vehicle communication system is envisioned that allows vehicles to exchange self-status updates aiming to extend their effective field of view and thus compensate for the limitations of the vehicle tracking subsystem that relies substantially on onboard sensing devices. Tracking capability in such systems can be further improved through the cooperative sharing of locally created map data instead of transmitting only self-update messages containing core basic safety message (BSM) data. In the cooperative sharing of safety messages, it is imperative to have a scalable communication protocol to ensure optimal use of the communication channel. This dissertation contributes to the analysis of the scalability issue in vehicle-to-everything (V2X) communication and then addresses the range issue of situational awareness in CAV systems by proposing a content-adaptive V2X communication architecture. To that end, we first analyze the BSM scheduling protocol standardized in the SAE J2945/1 and present large-scale scalability results obtained from a high-fidelity simulation platform to demonstrate the protocol\u27s efficacy to address the scalability issues in V2X communication. By employing a distributed opportunistic approach, the SAE J2945/1 congestion control algorithm keeps the overall offered channel load within an optimal operating range, while meeting the minimum tracking requirements set forth by upper-layer applications. This scheduling protocol allows event-triggered and vehicle-dynamics driven message transmits that further the situational awareness in a cooperative V2X context. Presented validation results of the congestion control algorithm include position tracking errors as the performance measure, with the age of communicated information as the evaluation measure. In addition, we examine the optimality of the default settings of the congestion control parameters. Comprehensive analysis and trade-off study of the control parameters reveal some areas of improvement to further the algorithm\u27s efficacy. Motivated by the effectiveness of channel congestion control mechanism, we further investigate message content and length adaptations, together with transmit rate control. Reasonably, the content of the exchanged information has a significant impact on the map accuracy in cooperative driving systems. We investigate different content control schemes for a communication architecture aimed at map sharing and evaluate their performance in terms of position tracking error. This dissertation determines that message content should be concentrated to mapped objects that are located farther away from the sender to the edge of the local sensor range. This dissertation also finds that optimized combination of message length and transmit rate ensures the optimal channel utilization for cooperative vehicular communication, which in turn improves the situational awareness of the whole system

VANET SECURITY FRAMEWORK FOR LOW LATENCY SAFETY APPLICATIONS

Vehicular Ad hoc Network (VANET) is a communication network for vehicles on the road. The concept of VANET is to create communication between vehicles, such as one vehicle is able to inform another vehicle about the road conditions. Communication is possible by vehicle to vehicle (V2V) and vehicle to road side unit (V2R). Presently, VANET technology is surrounded with security challenges and it is essentially important for VANET to successfully implement a security measure according to the safety applications requirements. Many researchers have proposed a number of solutions to counter security attacks and also to improve certain aspects of security i.e. authentication, privacy, and non-repudiation. The current most suitable security scheme for VANET is an Elliptic Curve Digital Signature Algorithm (ECDSA) asymmetric security mechanism. ECDSA is small in key size but it provides the same level of security as the large key sized scheme. However ECDSA is associated with high computational cost, thus lacking applicability in life-critical safety messaging. Due to that reason, alternative security schemes have been proposed, such as symmetric methods which provide faster communication, but at the expense of reduced security. Hence, hybrid and hardware based solutions have been proposed by researchers to mitigate the issue. However, these solutions still do not satisfy the existing safety applications standard or have larger message size due to increased message drop ratio. In this thesis, a security framework is presented; one that uses both standard asymmetric PKI and symmetric cryptography for faster and secured safety message exchange. The proposed framework is expected to improve the security mechanism in VANET by developing trust relationship among the neighboring nodes, hence forming trusted groups. The trust is established via Trusted Platform Module (TPM) and group communication. In this study, the proposed framework methods are simulated using two propagation models, i.e. two ray ground model and Nakagami model for VANET environment (802.11p). In this simulation, two traffic scenarios such as highway and urban are established. The outcome of both simulation scenarios is analyzed to identify the performance of the proposed methods in terms of latency (End-to-End Delay and Processing Delay). Also, the proposed V2V protocol for a framework is validated using a software in order to establish trust among vehicles

Co-projecto em FPGA da MAC IEEE 802.11p para comunicações veiculares

Mestrado em Engenharia Electrónica e TelecomunicaçõesThe advancements and dissemination of telecommunication technologies has caused them to be employed more and more in our day-to-day life. Recently, these technologies have been applied to vehicles, as a way of not only improving driving safety but also the drivers' and passengers' comfort. If vehicular communications are to become a reality, communication standards must be created in order to allow the development of compatible communication platforms, while also serving as a basys for application development. The standards IEEE WAVE, alongside the IEEE 802.11p amendment, were proposed in order to meet these demands and address some of the speci c issues with vehicular networks, such as short connectivity times and the highly dynamic nature of the propagation environment. This thesis ts within the HEADWAY project, the goal of which is the creation of a device that will perform communication between vehicles. In order to incorporate every layer of the WAVE (Wireless Access in Vehicular Environments) protocol stack, a development platform was conceived that will enable the creation of a standardized communications system for vehicles. The development platform created features an antenna, RF modules, DAC and ADC circuits, an FPGA, a general purpose microprocessor and a GPS module. This work is focused in the development and implementation in FPGA of a MAC layer in accordance with the WAVE standards. The MAC layer's di erent functionalities were divided according to their complexity and execution time, causing our MAC's division in Upper MAC (UMAC) and Lower MAC (LMAC). The UMAC will be implemented in software (C) running in an FPGA embedded microprocessor and will contain the MAC's functions that are more complex, algorithmically speaking, but are not required to be excuted in a very short time interval, such as frame processing and decoding. The LMAC will be implemented by VHDL modeled hardware logic and will perform time critical functions, such as the timestamping of received frames, and complex calculations that bene t from the paralelism o ered by hardware logic, such as CRC computation and error checking. This MAC layer was implemented in an FPGA and its mechanisms were validated

Characterization, Avoidance and Repair of Packet Collisions in Inter-Vehicle Communication Networks

This work proposes a combined and accurate simulation of wireless channel, physical layer and networking aspects in order to bridge the gaps between the corresponding research communities. The resulting high fidelity simulations enable performance optimizations across multiple layers, and are used in the second part of this thesis to evaluate the impact of fast-fading channel characteristics on Carrier-Sense Multiple Access, and to quantify the benefit of successive interference cancellation

Characterization, Avoidance and Repair of Packet Collisions in Inter-Vehicle Communication Networks

This work proposes a combined and accurate simulation of wireless channel, physical layer and networking aspects in order to bridge the gaps between the corresponding research communities. The resulting high fidelity simulations enable performance optimizations across multiple layers, and are used in the second part of this thesis to evaluate the impact of fast-fading channel characteristics on Carrier-Sense Multiple Access, and to quantify the benefit of successive interference cancellation

High performance simulation and modelling of wireless vehicular ad hoc networks

Vehicular communications occur when two or more vehicles come into range of one another, to share data over wireless media. The applications of this communication are far-reaching, from toll collection to collision avoidance. Due to the proliferation of wireless devices and their ubiquitous nature it is now possible to operate in an ad hoc manner between transmitting stations. Vehicular ad hoc networks (VANET) are a special kind of network, that experience short link times and high levels of interference, but have the ability to present many driver information and safety solutions for the worlds roads. Computer simulation of VANET enables rapid-prototyping and intensive exploration of systems and protocol, using highly complex and computationally expensive models and programs. Experimentation with real vehicles would be time consuming and expensive, limiting the range of study that could be achieved and therefore reducing the accuracy of analytical solutions exposed through experimentation. An extensive corpus of work on networking, traffic modelling and parallel processing algorithm has been reviewed as part of this thesis, to isolate the current state-of-the-art and examine areas for novel research. In this thesis the value and importance of computer simulation for VANET is proposed, which explores the applications of a high-fidelity system when applied to real-world scenarios. The work is grounded on two main contributions: 1) that by using intervehicle communication and an advanced lane changing/merging algorithm the congestion that builds up around an obstruction on a highway can be alleviated and reduced more effectively than simple line-of-sight, even when only a proportion of the vehicles are radio equipped. 2) that the available parameter space, as large as it is, can be efficiently explored using a parallel algorithm with the NS-3 network simulation system. The large-scale simulation of VANET in highway scenarios can be used to discover universal trends and behaviours in the successful and timely delivery of data packets. The application of VANET research has a broad scope for use in modern vehicles and the optimisation of the transmission of data is highly relevant; a large number of parameters can be tuned in a networking device, but knowing which to tune and by how much is paramount to the operation of intelligent transport systems