Hybrid Caching Transmission Scheme for Delay-sensitive Service in Vehicular Networks

With the inspiring development of vehicular networks, caching popular contents in the network edge nodes could greatly enhance the quality of user experience. However, the highly dynamic movements of vehicles make it difficult to maintain stable wireless transmission links between vehicle-to-vehicle pairs or vehicle-to-road side units (RSUs) pairs, and then resulting in unbearable transmission delays or even transmission interruptions. In this paper, we proposed a predictive and hybrid caching transmission scheme for delay-sensitive services in vehicular networks. In order to select the most proper node for transmitting desired content from the nearby RSUs or vehicles, we evaluate the candidate nodes from the prediction on effective communication range and connection time based on the relative velocities and SINR threshold. Then the end-to-end delay for respective nodes is compared which includes two parts: waiting period and transmitting period. Waiting period is predicted based on the relative distance and relative velocities between two nodes at the starting position. Transmitting period is calculated from the transmission rate and effective communication range. The candidate node with the lowest delay is selected to transmit the desired content to the destination vehicle. Simulation results show that the proposed scheme could significantly reduce time delays in data transmission, especially when the requesting vehicle is far from the nearest RSU.