Matching-Based Content Caching in Heterogeneous Vehicular Networks

To cope with the explosive vehicular content demands from various applications and services, it is imperative to cache the content files close to end users to reduce both the core network traffic load and the delivery delay. The heterogeneous vehicular networks provide multiple data pipes to access to the Internet for vehicles, and thus can be leveraged to cache the required content files on different access network edges and further improve the caching effectiveness. This paper focuses on the content delivery in heterogeneous vehicular networks that allow content caching in roadside WiFi APs, TV White Space Stations, and Cellular Base Stations. With the objective of minimizing the content delivery delay, a Student Admission matching- based content caching scheme is proposed by considering the file popularity, vehicle mobility and cache capacity of the edge infrastructure in heterogeneous vehicular networks, whereby a stable result is further obtained via the Gale-Shapley algorithm. Our simulation results demonstrate the advantages of the proposed caching scheme.

I. Introduction

The Internet of Vehicles (IoV) are envisioning enhanced driving experience and road efficiency for future transportation by connecting vehicles to their internal and external environments [1], [2]. As the number of vehicles on road is increasing tremendously, the data content requirement from various vehicular applications and services are soaring at a tremendous pace. However, cellular spectrum resources and capacity of backhaul links have not grown at a similar pace due to the high cost of infrastructure upgrade. Although the Federal Communications Commission (FCC) has allocated 75 MHz bandwidth at the 5.9 GHz spectrum band for dedicated short-range communications (DSRC) for vehicular communications, these limited spectrum resource cannot afford the data tasks for future vehicle users. Stemming from the observations in [3], a large portion of mobile multimedia traffic can be attributed to duplicated downloads of a small fraction of popular content files. As current network infrastructures and modern vehicles are often equipped with enhanced computing capability and the storage capacity, it is possible to cache the popular files closer to the user end, which can significantly offload backhaul traffic and reduce delivery delay [4]–[6].