A Low-Latency Content Dissemination Scheme for mmWave Vehicular Networks

In future vehicular networks, to satisfy the ever-increasing capacity requirements, ultrahigh-speed directional millimeter-wave (mmWave) communications will be used as vehicle-to-vehicle (V2V) links to disseminate large-volume contents. However, the conventional IP-based routing protocol is inefficient for content disseminations in high-mobility and dynamic vehicular environments. Furthermore, the vehicle association also has a significant effect on the content dissemination performance. The content segment diversity, defined as the difference of desired content segments between content requesters and content repliers, is a key consideration during vehicle associations. The relative velocity between vehicles, which highly influences the link stability, should also been taken into account. The beam management, such as the beamwidth control, determines the link quality and, therefore, the final content dissemination rate. Based on the above observations, to improve the content dissemination performance, we propose an information-centric network (ICN)-based mmWave vehicular framework together with a decentralized vehicle association algorithm to realize low-latency content disseminations. In the framework, by using the ICN protocol, contents are cached and retrieved at the edge of the network, thereby reducing the content retrieval latency. To enhance the content dissemination rate, the vehicle association algorithm, which jointly considers the content segment diversity, the relative velocity between vehicles, and the transceiver's beamwidths, is operated in every vehicle. Considering the blindness of directional mmWave links, a common control channel operating at low frequency bands with omni-directional coverage is used to share the information related to vehicle associations. The simulation results demonstrate that the proposed algorithm can improve the content dissemination efficiency and reduce the content retrieval latency.