Cooperative Gateway Cache Invalidation Scheme for Internet-Based Vehicular Ad Hoc Networks

Internet-based vehicular ad hoc network is a fast growing technology with an aim to provide uninterrupted services such as regular safety alerts, entertainment, and resource sharing to the on board passengers even on-the-fly. On board passengers avail all these services even on-the-fly either in dense urban regions, or on highway using an Internet connection. Reduction in delay with an increase in the accuracy for accessing all these services from anywhere are the most challenging tasks to be performed in this environment. In literature, it has been found that caching the most relevant content at some of the intermediate sites may increase the overall performance of the network in this environment. In this direction, an important issue is to invalidate the cache when the original data items are updated and these data items are irrelevant for the end users. In this paper, we have been motivated and inspired from our earlier solution (Kumar and Lee in IEEE Syst J 8(4):1136-1144, 2014), in which we proposed a peer-to-peer cooperative caching scheme among the vehicles for urban scenario. But, in the current proposed scheme, we have enhanced our existing solution by proposing a Cooperative Gateway Cache Invalidation (CGCI) based upon cooperative cache invalidation technique. The designed scheme has the advantages of cooperation of Gateways in different regions along with the underlying location management scheme to reduce the number of broadcast operations, lesser Uplink requests, and query delay with an increase in the cache hit ratio. To test the effectiveness of the proposed scheme, we carried out extensive simulations by varying query arrival rate, object update rate, and cache size. Moreover, to evaluate the cost of query communication among the vehicles, an analytical model is also included in the proposed scheme. The results obtained confirm that the proposed scheme yields a reduction in the query delay with an increase in the cache hit ratio as compared to other state-of-the art existing schemes in literature.