Spectrum Allocation And Sharing Strategy With QOS Support In Cognitive Cooperative Vanet

As the basic information bearing platform of intelligent transportation system, vehicle ad-hoc network is composed of global positioning system (GPS), wireless sensor and wireless communication technology. VANET is a comprehensive network enabling the exchange of safety and non-safety information among vehicles or between vehicles and fixed road side unit. It can offer a more secure, efficient and comfortable driving environment for the drivers. However, with the increasing communication demand of diverse wireless applications, the limited and static spectrum can result in severe message access delay and packet loss rate. Thus, a novel Cognitive Cooperative VANET (CC-VANET) is proposed to solve the contradiction between the increasing demand of diverse wireless applications and the shortage of spectrum resource. The cognitive radio technology enables VANET to use additional spectrum opportunities outside the standard5.9GHz band. And the cooperative communication can improve the reliability of communication link and the spectrum usage efficiency.The general system architecture of CC-VANET is proposed and key technologies will also be researched in this paper. We propose a novel adaptive cognitive spectrum sensing scheme and mainly focus on the wireless resource management in vehicular network. And the dyanamic spectrum sharing stategy will be deeply researched to improve the wireless spectrum utility. Considering the features of CC-VANET, a two-step spectrum sharing strategy with QoS support is developed in this paper. And it consists of inter-cell allocation and intra-cell allocation. Firstly, in order to formulate the inter-cell asymmetric resource allocation, Generalized Nash Bargaining Solution (GNBS) is proposed to achieve a good tradeoff between efficiency and weighted fairness. Then, considering the various load states and primary user activity which can cause influence to fairness, a two-band partition spectrum allocation algorithm is developed to support the QoS of VANET. Finally, to improve the overall utility and fairness between OBUs, we propose a novel cooperative spectrum sharing scheme based on cognitive cooperative model in a single cell.Simulation results indicate that the proposed GNBS scheme which considers both the fairness and utility can obtain larger transmission rate than Max-min scheme and achieve much better fairness than Max-rate scheme. Considering the difference of requirements between cognitive cells, GNBS scheme can allocate the spectrum resource dynamically in a weighted fairness manner. Furthermore, the cognitive cooperative spectrum sharing scheme can greatly improve the system utility and fairness between OBUs than the non-cooperative schemes.