Tracking-based Cooperative Caching in VANETs for Social Networking

Abstract

Social media traffic is the predominant source of Internet traffic. Such traffic is primarily facilitated by mobile devices. As a result, mobile users tend to sustain high cellular costs. To alleviate such costs, we endeavor to allow social media users to depend more on vehicular rather than cellular networks for data access. However, this can be thwarted by the high delay and low packet delivery ratio often coupled with content access from distant data providers in vehicular networks. Hence, we strive to get the data closer to the requester by proposing the Cooperative Content Discovery and Placement at Vehicles (CCDPV) scheme. In CCDPV, we dynamically discover closer replicas to the requester using parked and moving vehicles. In particular, we utilize the last encounter information, as well as the static and mobile nature of parked and moving vehicles, respectively, to diffuse cached content information, track caching nodes, and dynamically locate closer caching nodes to the requester. CCDPV applies cooperative cache placement at both parked and moving vehicles. It caches data at parked vehicles located in congested road segments to cater for the higher possibility of requests occurring at them. CCDPV caches data at moving vehicles while taking data diversity relative to the vehicles direction of movement into consideration. Performance evaluation shows that CCDPV significantly improves delay, packet delivery ratio, and cache hit ratio compared to a caching scheme in vehicular networks that has some implicit cooperative features, as well as to a tracking-based cooperative cache discovery scheme in mobile ad hoc networks.