In this paper, we develop a comprehensive and tractable analytical framework based on stochastic geometry to evaluate the performance of large-scale fog-aided device-to-device (F-D2D) networks with opportunistic content multicasting. As a part of the analysis, to resolve the contentions of file requests from the cache-incapable conventional user equipments (C-UEs), two simple yet typical candidate file selection schemes for cache-enabled fog user equipments (F-UEs), namely the random file selection (RFS) scheme and the most requested file selection (MRFS) scheme, are considered. Further, to suppress the harmful interference among the concurrent transmissions of F-UEs, a multicast-based opportunistic content delivery strategy is proposed by exploring the idea of opportunistic spectrum access (OSA). Assuming decentralized probabilistic caching, we first derive the activation probability of the F-UEs. Then, by adopting an appropriate approximation, the cache-hit probability, the coverage probability, and thereby the successful content delivery probability (SCDP) of the F-D2D network are evaluated. We also develop an iterative algorithm based on the gradient projection method to obtain a suboptimal caching policy for the maximization of SCDP. Extensive simulation and numerical results are presented to verify our analysis and demonstrate the superior performance of the proposed multicast-based opportunistic content delivery strategy.

翻译：在本文中,我们根据随机文件选择(RFS)办法和最请求的文件选择(MRFS)办法,根据随机文件选择(F-DFS)办法,制定了一个全面、可移植的分析框架,以评价具有机会性内容的大型迷雾设备到设备网络的性能。作为分析的一部分,我们为解决来自缓存不可获取的常规用户设备(C-Ues)的文件请求的争论,有两个简单而典型的缓存雾用户设备(F-Ues)的候选文件选择办法,即随机文件选择(RFS)办法和最请求的文件选择(MRFSFS)办法。此外,为了制止同时传输F-Ues的有害干扰,还提出了一项基于多种选择的机会性内容交付战略。作为分析的一部分,我们通过探索机会性频谱访问(OSA)的理念,提出了基于缓存能力分散的常规用户设备(C-UES)的档案请求。假设F-UE的启动概率。然后,通过适当的近似性、缓存概率、覆盖概率,从而评估F-D网络成功提供内容的可能性(SCDP)的交付概率。 我们还在同时传输机会性内容中,我们还提出了一个基于透明性战略的升级分析,以展示结果的高级分析。我们提出了一个模拟分析。