Cooperative Vehicular Ad-hoc Networks Research Articles

Throughput and Outage Probability-Aware Intelligent Swarm-Based Multi-Hop Selection in Vehicular Network

Cooperation is an emerging paradigm for improving spatial differentiation in Vehicular Ad-Hoc Networks (VANETs). Hence, many network solutions are motivated through cooperative communications for boosting VANET efficiency regarding specific network constraints like energy efficiency, network capacity, and outage probability. The main intention of this paper is to design and develop an optimization model for selecting the minimum number of multi-hops between the source and destination for the cooperative VANET networks. The first phase has a first-time slot, where a signal is transmitted by the source to the cooperative nodes (its relays) and their equivalent destination. The main problem considered here is to optimally select the number of hops or relays that are adaptable for communication, to solve the multi-objective functions concerning the target throughput and outage probability. The adoption of new Dimension-based Cat Swarm Optimization (D-CSO) is the main contribution here to optimally select the multi-hops among source and destination. Through the performance evaluation, it is observed that the designed model has achieved networks-wide fairness performance and a good convergence rate.

Cooperative spectrum allocation with QoS support in cognitive cooperative vehicular ad hoc networks

To solve the contradiction between the increasing demand of diverse vehicular wireless applications and the shortage of spectrum resource, a novel cognitive cooperative vehicular ad-hoc network (CC-VANET) framework is proposed in this paper. Firstly, we develop an adaptive cognitive spectrum sensing (ACSS) mechanism which can help to trigger and adjust the spectrum sensing window according to network traffic load status and communication quality. And then, Generalized Nash Bargaining Solution (GNBS), which can achieve a good tradeoff between efficiency and weighted fairness, is proposed to formulate the asymmetric inter-cell resource allocation. Finally, GNBS-Safety (GNBS-S) scheme is developed to enhance the Quality of Service (QoS) of safety applications, especially in the heavy load status, where the bandwidth demanded and supplied cannot be matched well. Furthermore, the primary user activity (PUA) which can cause rate loss to secondary users, is also considered to alleviate its influence to fairness. Simulation results indicate that the proposed CC-VANET scheme can greatly improve the spectrum efficiency and reduce the transmission delay and packet loss rate on the heavy contention status. And GNBS spectrum allocation scheme outperforms both the Max-min and Max-rate schemes, and can enhance the communication reliability of safety service considerably in CC-VANET.

Connectivity Analysis for Cooperative Vehicular Ad Hoc Networks Under Nakagami Fading Channel

User behaviors like inter-vehicle cooperation have a significant impact on vehicular network connectivity. Intuitively, the network performance can be boosted by introducing cooperation. However, an increasing number of cooperative vehicles may result in increased interference and thus negatively affect the system performance. In this letter, we present an analytical framework to study the impact of the cooperative vehicle ratio on connectivity probability under Nakagami fading channel for both cases of independently non-identically and identically distributed interference. The lower bound of the optimal cooperative ratio is derived to explicitly reveal its relation with system parameters when interference are identically distributed. Numerical results are supplemented by simulations to demonstrate the accuracy of the analytical framework and provide useful guidelines for estimating connectivity performance in the network design for scheduling policy in vehicular networks.

Contextual and Applications-Aware Communications Protocol Design for Vehicle-to-Vehicle Communications

Cooperative vehicular ad-hoc networks are currently under development for improving traffic safety and efficiency. The strict requirements of traffic safety applications demand robust communication protocols that are able to efficiently operate under diverse and challenging operating conditions. In this context, this work proposes the joint study and evaluation of cooperative applications with potential dependencies, and evaluates a context-aware communications mechanism that exploits traffic context information to maximize the applications' effectiveness. The benefits of the proposed approach are illustrated with the intersection collision warning and emergency electronic brake lights applications.

Contextual Communications Congestion Control for Cooperative Vehicular Networks

The wide scale deployment of cooperative vehicular ad-hoc networks will require the design of efficient congestion control policies that guarantee stable and reliable communications between vehicles and with infrastructure nodes. These policies should reduce the load on the communications channel, while satisfying the strict application's reliability requirements. To this aim, this letter proposes and evaluates a contextual cooperative congestion control policy that exploits the traffic context information of each vehicle to reduce the channel load, while satisfying the vehicular applications requirements.