Weirong Jiang

A Cross-Layer AOMDV Routing Protocol for V2V Communication in Urban VANET

Vehicular Ad hoc Network (VANET) is a special class of wireless mobile communication network. For vehicle-to-vehicle (V2V) communication, suitable routing protocols are needed. A routing metric combining hop counts and retransmission counts at MAC layer is proposed with consideration of link quality and delay reduction. Based on the new routing metric, a cross-layer Ad hoc On-demand Multipath Distance Vector with retransmission counts metric (R-AOMDV) routing protocol is designed to make use of advantages of multi-path routing protocol, such as decrease of route discovery frequency. Compared with AOMDV with minimum hop-count metric, simulation results show that R-AOMDV achieves better performance with Pareto On/Off distribution traffic model in urban VANET, no matter in sparse or dense scenarios.

An improved AOMDV routing protocol for V2V communication

Active security and intelligent transportation are important Vehicular Ad hoc Network (VANET) applications, which need suitable vehicle-to-vehicle communication technology, especially routing technology. When designing routing protocol for VANET, driving information of vehicles can be used as routing metrics, which can provide additional routing information. A routing metric combining hop and speed is proposed with consideration of vehicle driving information employment and delay reduction. Also a driving information collecting module is designed and implemented using On-Board Diagnostic (OBD) technology to collect speed information in real time without any modification of vehicles. Based on the new routing metric, an improved Ad hoc On-demand Multipath Distance Vector with speed metric (S-AOMDV) routing protocol is designed to make use of advantages of multi-path routing protocol, such as fault-tolerant and load balance. Compared with AOMDV with minimum hop-count metric, simulation results show that S-AOMDV achieves better performance.

An adaptive cross-layer multi-path routing protocol for urban VANET

For vehicle-to-vehicle (V2V) communication, suitable routing protocols are needed. An adaptive cross-layer multi-path routing protocol, R-S-AOMDV, is proposed. The routing metric combines hop-count, link-quality and vehicle-motion information. To make use of advantages of multi-path routing protocol, such as decrease of route discovery frequency, the protocol is designed based on the improvement of AOMDV (Ad hoc On-demand Multipath Distance Vector) routing protocol. Compared with AOMDV with minimum hop-count metric, simulation results show that R-S-AOMDV achieves better performance, no matter in sparse or dense urban VANET (Vehicular Ad hoc NETwork).

Design and implementation of multi-source vehicular information monitoring system in real time

Vehicular applications are the bases of vehicle value-added services in the future, which depend on real-time access to multi-source vehicular information. In order to be applied to vehicles in use easily, the implementation of vehicular applications should avoid modifying vehicles and control the increase of wiring harness to decrease system complexity. A vehicular information real-time monitoring framework is proposed, which can collect, transfer and display vehicle driving information, such as velocity and trouble codes, and environment information, such as GPS and video around the car. A flexible and reliable communication protocol is designed to exchange multi-source information between modules in the framework. On-Board Diagnose (OBD) technology and wireless technology are used to collect vehicle driving information to avoid modifying vehicles, and to transfer information to control the increase of wiring harness, respectively. The prototype system is tested on a car, and the results show that the system can be used easily as a basis for future vehicular applications based on multi-source information fusion.

Vehicle Auxiliary Anti-Collision Warning System Based on Positioning in Electronic Map

After studying the existing methods of collision detection and early warning, a vehicle auxiliary anti-collision warning system based on positioning in electronic map is proposed. In this system, OBD, GPS, vehicle sensor and wireless LAN technologies are used to obtain the driving information of a vehicle itself and other vehicles around, and map positioning technologies to display the positions of vehicles in the map. The collision probability of personalization is used to determine the alarm time. Experiments show that the system can be used in LOS and NLOS scenarios, and can effectively avoid collision among vehicles.

The effects of advanced information feedback strategies in FI model

Advanced Traveler Information System provides travelers with real-time transportation information, which can satisfy the dynamic requirements of travelers and increase the ability of transportation infrastructure. Many information feedback strategies are proposed based on the real-time information of roads and vehicles. There are some typical information feedback strategies: Travel Time Feedback Strategy (TTFS), Mean Velocity Feedback Strategy (MVFS), and Congestion Coefficient Feedback Strategy (CCFS). However, all the above information strategies are used in NS model. The effects of the above information feedback strategies in other models have not been studied. The effects of the above information feedback strategies in FI model are validated in this paper. Results show that the above strategies are applicable to FI model.

An Improved Information Feedback Strategy for Symmetrical Two-Route Traffic Flow Model

Advanced Traveler Information System (ATIS) can provide travelers with real-time traffic information, which will increase the traffic efficiency. An improved information feedback strategy, Weighted Mean Velocity Feedback Strategy (WMVFS) is proposed. With WMVFS, simulation results show that better performance is achieved compared with Mean Velocity Feedback Strategy (MVFS). The mean value of average flux with our strategy is 4.25% higher than that with MVFS, which means the traffic efficiency increases. And the coefficient of variation of average flux with our strategy is 52.25% lower than that with MVFS, which means the fluctuation is suppressed. Other results of performance metrics, mean velocity, vehicle number and travel time show the same conclusions. The influence of density of dynamic vehicles on average flux is analyzed. The results show that our strategy is more stable when the density of dynamic vehicles changes than MVFS.

Implementing Ad hoc On-demand Multipath Distance Vector routing protocol in Linux

Multi-path routing protocol attracts more and more attention because the routing performance can be improved by making use of advantages of multi-path routing protocol, such as fault-tolerant and load balance. To validate multi-path routing protocol in real environment, the Ad hoc On-demand Multipath Distance Vector (AOMDV) routing protocol is implemented in Linux based on AODV-UU. The functions of AOMDV protocol are implemented in user space, and the interaction with the kernel is implemented based on Netlink and Netfilter. Experimental results validate the implementation of AOMDV.