2 research outputs found
Energy Efficient Route Planning Using VANET
One of the key challenges in conducting dynamic route planning is the process of collecting and disseminating instantaneous travel data in real time. Recent studies are evaluating VANET (Vehicular Ad Hoc Network) and its associated WAVE (Wireless Access in Vehicular Environment) standards to facilitate this process. In these studies, travel data accumulated from vehicle OBUs (on board unit) are shared with other vehicles over DSRC (dedicated short- range communication) medium using centralized or distributed approach. In most studies, data collection and dissemination process are not scalable enough for high density traffic environment. Specifically, with a centralized approach, if traffic management center (TMC) or Road Side Unit (RSU) performs route planning for vehicles, there will be many bidirectional communications between the centralized entity and vehicles, leading to higher channel congestion in heavy traffic areas. With a distributed approach, information shared by other vehicles might not be useful or pertinent for some vehicles, leading to wastage of channel bandwidth. Methods used for data collection also need to be intelligent to count in nontraditional circumstances to achieve accuracy. In this thesis, we have proposed a three tiered architecture for data collection, analysis and dissemination. In addition, 1) we demonstrated the concept of queuing delay at intersection for travel time calculation and developed a hybrid metric that considers average travel time and occupancy rate, 2) we offload the computation of route planning to vehicle OBUs and 3) we developed an algorithm that determines the area of propagation for data that needs to be disseminated. We evaluated the performance of our approach progressively using VEINS, SUMO and OMNET++ simulators
Capacity analysis in different systems exploiting mobility of VANETs
Improving road safety and traffic efficiency has been a long-term endeavor for not only government but also automobile industry and academia. After the U.S. Federal Communication Commission (FCC) allocated a 75 MHz spectrum at 5.9 GHz for vehicular communications, the vehicular ad hoc network (VANET), as an instantiation of the mobile ad hoc network (MANET) with much higher node mobility, opens a new door to combat the road fatalities. In VANETs, a variety of applications ranging from safety related (e.g. emergency report, collision warning) to non-safety-related (e.g. infotainment and entertainment) can be enabled by vehicle-to-vehicle (V2V) and vehicle-to-roadside (V2R) communications. However, the flourish of VANET still hinges fully understanding and managing the challenges that the public concerns, for example, capacity and connectivity issues due to the high
mobility of vehicles.
In this thesis, we investigate how vehicle mobility can impact the performance in three important VANET-involved systems, i.e., pure VANET, VANET-enhanced intelligent transportation systems (ITS), and fast electric vehicle (EV) charging systems. First, in pure VANET, our work shows that the network data-traffic can be balanced and the network throughput can be improved with the help of the vehicle mobility differentiation. Furthermore, leveraging vehicular communications of
VANETs, the mobility-aware real-time path planning can be designed to smooth
the vehicle traffic in an ITS, through which the traffic congestion in urban scenarios can be effectively relieved. In addition, with the consideration of the range anxiety caused by mobility, coordinated charging can provide efficient charging plans for electric vehicles
(EVs) to improve the overall energy utilization while preventing an electric power system
from overloading. To this end, we try to answer the following questions:
Q1) How to utilize mobility characteristics of vehicles to derive the achievable asymptotic
throughput capacity in pure VANETs?
Q2) How to design path planning for mobile vehicles to maximize spatial utility based on
mobility differentiation, in order to approach vehicle-traffic capacity in a VANET-enhanced ITS?
Q3) How to develop the charging strategies based on mobility of electric
vehicles to improve the electricity utility, in order to approach load capacities of charging
stations in VANET-enhanced smart grid?
To achieve the first objective, we consider the unique features of VANETs and derive the scaling law of VANETs throughput capacity in the data uploading scenario.
We show that in both free-space propagation and non-free-space propagation environments, the achievable throughput capacity of individual vehicle scales as nQ1Q2Q3$ of the thesis are meaningful in exploiting/leveraging the vehicle mobility differentiation to improve the system performance in order to approach the corresponding capacities