Vehicle Pairing, Spectrum Assignment and Power Control for Non-Safety Critical Services in Heterogeneous Vehicular Networks

Abstract

To accommodate the ever-increasing demands for non-safety critical services in vehicular networks, heterogeneous vehicular networks (HVNs) have been proposed and drawn considerable attention. It is known that the performance of HVNs suffers from a shortage of spectrum resource, and the relatively low utilization of licensed spectrum makes the spectrum shortage even worse. To cope with this, by introducing unlicensed spectrum into HVNs, we investigate the spectrum efficiency (SE)-oriented collaborative transmission. The SE for HVNs depends highly on the channel state information (CSI) of the effective communication links which are normally determined by the vehicle pairing. So, we first propose a joint social-physical domain vehicle pairing algorithm (JSPD-VPA), and then formulate an optimization problem to maximize the SE of vehicle-to-everything (V2X) communications while guaranteeing the quality of services (QoS) requirements of cellular users in licensed spectrum and users in unlicensed spectrum. Considering that the formulated problem is NP-Hard problem, to solve it, the formulated problem is decomposed into two subproblems, i.e., spectrum assignment subproblem and power control subproblem. An optimal hypergraph coloring algorithm is proposed to solve the spectrum assignment subproblem, and a low-complexity three-dimensional geometry approach is developed to solve the power control subproblem. Simulation results reveal that the proposed vehicle pairing, spectrum assignment and power control algorithm (VP-SA-PCA) can greatly enhance the SE and outperforms the baselines around 7%-37% within a certain range. Moreover, the superiority of the proposed JSPD-VPA has been validated.