In current research of device-to-device (D2D) caching strategies, when terminals request and receive files within the transmission range, the effect of file redundancy and idle loss rate of the cache in terminals are rarely considered. In this study, the authors establish a motion and the transfer model of D2D terminals, and define a loss function considering cache idle loss and file redundancy. Then the relationship between the cache size and the number of terminals is analysed, and the optimal cache size is calculated according to the loss function. Through the analysis, the authors can see that the performance of the D2D caching network is almost constant when the product of the buffer size and the number of terminals is constant. Therefore, inspired by the above analysis and results, the authors devise an adaptive caching strategy, which determines the file caching method according to the comparison of the actual size of the terminal cache and the optimal cache size with respect to the loss function. Simulation results indicate that, compared with other caching schemes, the proposed adaptive strategy yields a significantly higher cache-hitting rate and less delay.

中文翻译：

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用于设备到设备通信的丢失感知自适应缓存方案

在当前的设备到设备（D2D）缓存策略研究中，当终端在传输范围内请求和接收文件时，很少考虑文件冗余和终端中缓存的空闲丢失率的影响。在这项研究中，作者建立了D2D终端的运动和传输模型，并考虑了高速缓存的空闲丢失和文件冗余来定义丢失函数。然后，分析了高速缓存大小与终端数量之间的关系，并根据损失函数计算出最佳的高速缓存大小。通过分析，作者可以看到，当缓冲区大小和终端数量的乘积恒定时，D2D缓存网络的性能几乎是恒定的。因此，受以上分析和结果的启发，作者设计了一种自适应缓存策略，它根据终端缓存的实际大小与丢失函数的最佳缓存大小的比较来确定文件缓存方法。仿真结果表明，与其他缓存方案相比，所提出的自适应策略产生了更高的缓存命中率和更少的延迟。