# IBP Based Caching Strategy in D2D
## 2 Related Works  
By deploying caching into D2D communication, QoE (Quality of Experience) and QoS (Quality of Service) of users can be significantly improved. The authors have proved that the D2D network with caching performs much better than other solutions [9]. They also proposed a Maximum Distance Separable coding based caching strategy for D2D, each device cache coded block with equal probability, the content can be recovered by obtaining enough coded blocks from other devices [12]. [PERSON] et al. applied caching into a spectrum sharing mechanism D2D network to improve D2D spectral efficiency [13]. [PERSON] et al. divided the D2D caching network into several clusters, then introduced two caching strategies, deterministic caching strategy and Zipf-Based Random caching strategy. For deterministic caching strategy, each device caches the content with high popularity without duplication. For random caching, the distribution of contents cached by devices randomly and independently follows Zifp distribution [14]. [PERSON] et al. used Poisson cluster process for modeling locations of devices and proposed a cluster-centric content placement strategy to optimize the performance of the whole cluster [15]. [PERSON] et al. proposed a clustering approach to optimize energy efficiency and throughout for based station assisted D2D caching network [16]. [PERSON] et al. proposed a D2D-aware caching policy for millimeter-wave network to achieve higher offloading and lower content-retrieval delays [17]. [PERSON] et al. obtained optimal transmission and caching by formulating caching to a continuous time optimization problem [18]. The authors in [19] proposed a mobility aware caching strategy, the devices with low-speed and high-speed cache most popular content, the other devices cache content with lower popularity. [PERSON] et al. proposed a Poisson Point Process based caching strategy for D2D to reduce latency, the locations of devices are modeled by Poisson Point Process, each device randomly caches a portion of content [20]. The authors proposed a probabilistic caching strategy for D2D caching network to maximize the cache hit rate and cache-aided throughput [21]. [PERSON] et al. proposed a user-centric protocol and optimized proactive caching scheme to obtain high offloading gain with low energy cost at helper users [22]. [PERSON] et al. designed a spatially correlated caching scheme, hard-core placement to increase cache hit rate. With the proposed scheme, the devices caching the same content are never closer to each other than the exclusion radius [23]. Recently, social relationship between users has been considered in D2D network. [PERSON] et al.  
proposed a socially-aware incentive approach to incentivize users to cache content for others and minimize total cost of the network for retrieving content [24]. A hypergraph framework is proposed by considering social ties, common interests and D2D transmission scheme for caching based D2D communications [25]. [PERSON] et al. defined a notion of socially-aware rate, then proposed a socially-aware rate based content sharing mode selection strategy and modelled it as a maximum weighted mixed matching problem [26]. [PERSON] et al. proposed a D2D relay-aided content caching strategy, which considers the different concentration levels of contents request from different users' groups and user's physical link [27].  
In summary, most D2D caching schemes are proactive caching and cannot update cached content in time. Moreover, they require accurate prediction of content popularity in future. Several studies focusing on frameworks and incentive schemes are proposed, which have considered social relationships between devices. In this paper, we propose an India Buffet Process based socially-aware caching strategy to improve caching efficiency. Each device determines whether to cache the received content independently according to contribution degree.