Research On Predictive Caching Scheme In Vehicular Content Centric Network

VCCN is a special network architecture that is combined with VANET and CCN.The rapid movement of nodes in VANET makes it difficult to maintain a stable network topology,resulting in excessive request forwarding and response delays.The caching mechanism in CCN aims to solve the problem that the request/response delay is too long by utilizing the cache space of the network node to store content,effectively reducing the delay.Therefore,it is an effective research method to apply the caching mechanism in CCN to VANET architecture.In this paper,we concern about the research of caching mechanism under the VCCN,and propose a cooperative caching mechanism based on node social attributes and mobility and a cache replacement strategy based on popularity prediction.In the cooperative caching mechanism,we consider a caching node sharing more social attributes with the content requester is more likely to be interested in the same contents and distribute the contents to others with similar interests.Furthermore,a caching node that frequently meets other nodes is a better candidate to keep cache copies.To increase the network performance,we also exploit the regularity of vehicle moving behaviors to predict the chance for a vehicle to reach hot zones based on Hidden Markov Model(HMM).In the cache replacement strategy,we adopt Hidden Markov Model(HMM)to predict the content popularity based on the inherent characters of the received interests,request ratio,request frequency and content priority and we propose a novel cache replacement scheme based on content future popularity.In this paper,the Opportunistic Network Environment Simulator(ONE)is used to simulate and verify the cooperative caching mechanism and cache replacement strategy.The performance is evaluated from the cache hit ratio,access delay and hop count of the request interest packet.At the same time,the cache performance of different types of nodes in the vehicular network environment is simulated.The simulation results show that the cooperative caching mechanism based on node social attributes and mobility and the cache replacement strategy based on popularity prediction effectively improve the overall service performance of the network,and have better cache hit ratio and access delay.