# Service-Oriented Cooperation Policies for Intelligent Ground Vehicles Approaching Intersections
###### Abstract  
With the coming of intelligent vehicles and vehicular communication, Intelligent Transportation Systems (ITS) of connected vehicles are emerging and now evolving to Cooperative-ITS (C-ITS), as service platforms for smart cities. Considering new service properties, the autonomous cooperation of such vehicles has exhibited novel QoS features that imply new requirements: guaranteeing the traffic efficiency of any emergent vehicle while trying to promote the throughput at an intersection. So, after analyzing the classic reservation-based cooperation mechanisms, new QoS-oriented cooperation methods and policies are studied in this work. Concretely, several models of related traffic objects we have proposed are firstly introduced briefly. Then, the scheduling policies of vehicles approaching an intersection have been presented, including three existing policies (FAFP-SV, FAFP-SQ, and HQEP-SV) and five new polices (FAFP-SQ-SV, FAFP-MQ, HWFP-SQ, HWFP-SQ-SV, HWFP-MQ). These policies combine two major factors: vehicular priority for scheduling and concurrency in traffics. The first one includes the vehicular arrival-time, priority mapped to QoS, and the weight of reserved vehicles on a lane etc. In addition, the second refers to schedule a platoon rather than single vehicle each time, or platoons on different lanes instead of one platoon on only one lane. All these policies have been implemented, and further, verified within the parameter-configurable traffic simulator QoS-CITS (v2.1) we designed and developed with C#. Abundant experiments have been conducted with configured typical traffic scenes, and experimental results show that HWFP-SQ-SV and HWFP-MQ can guarantee both the QoS of emergent vehicles and traffic throughput better than other six policies. Cooperative-ITS; intelligent vehicles; intersection; quality of service; policy; simulation +
Footnote †: journal: Applied  
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emerging stage of Intelligent Transportation Systems (ITS): Cooperative-ITS (C-ITS), and also, other similar swarm intelligent systems. As predicted in many important research projects, for instance the PATH program of USA, the European Union project AutoNet2030 etc. [1], V2X communication-based cooperation of intelligent vehicles is deservedly the main evolving trend for C-ITS, particularly for large-scale C-ITS because there are more advantages compared with current ITS, more perceptive, more efficient and safer. Considering these new characteristics, in the domain of C-ITS, a series of models and mechanisms for communication-based inter-vehicle cooperation have been studied, and obvious progress has been achieved in recent decades along with increasing interest from more researchers [2; 3; 4; 5]. Based on the capability of Vehicle-to-Infrastructure/Agent (V2I/V2A) and Vehicle-to-Vehicle (V2V) communication, such cooperation problems have been mainly reduced to basic sub-problems [6], typically two as shown in Figure 1. Figure 1a shows the vehicular cooperation at a crossroad. It corresponds to a problem called Passing-Through Intersection (PTI) [7], which mainly focuses on how to guarantee vehicles pass through an intersection safely and efficiently [8; 9]. And Figure 1b indicates the cooperation of vehicles when taking lane-changing or over-taking actions on roads [10]. Nevertheless, when considering service properties of future C-ITS, the connotations of these cooperation problems will become different from classic ones [11; 12; 13; 14], and consequently, current mechanisms will be greatly challenged by the following issues. * How to guarantee the traveling efficiency of emergent vehicles, as well as the traditional traffic safety and throughput? * How to manage vehicular behaviors synergistically in the complicated spatial-temporal serviced domain? * What novel cooperative policies will satisfy vehicular service properties?