In-Vehicle Caching (IV-Cache) Via Dynamic Distributed Storage Relay (D$^2$SR) in Vehicular Networks

In recent years, wireless communication demands from high-speed vehicles have rapidly increased, due to the enrichment of various emerging vehicular applications including road safety, intelligent transportation, in-vehicle entertainment, self-driving, etc. Such high communication demands may result in significant burden on the supporting infrastructure in vehicular networks, which, in turn, deteriorate the quality of experience of vehicular users. Caching popular contents at the edge of the network attracting increasing research interests lately, however, is significantly hindered by the vehicle mobility in vehicular scenarios. To cope with such an issue, this paper explores and proposes a judiciously designed framework termed as IV-Cache to facilitate in-vehicle caching in the vehicular scenario that specifically accounts for the vehicle mobility and vehicle-to-vehicle (V2V) communications vulnerability. At the foundation of this framework, we innovatively propose a storage scheme enhanced with dynamic relays among vehicles to account for the vehicle mobility. The key of the proposed data storage scheme is to maintain the storage data survival in a designated region of interest. Data redundancy by erasure codes is also introduced in order to combat the volatile V2V links. Based on dynamic distributed storage relay (D
²
SR), our designed IV-Cache can also flexibly accommodate multi-file popularity. Theoretical analysis and numerical results validate the effectiveness of our proposed D
²
SR and IV-Cache schemes. Specifically, the IV-Cache system could serve up to 95% of the requests for the cached popular contents, and the data stored at the D
²
SR system could survive for up to tens of hours under typical road conditions.