Mobile caching policies for device-to-device (D2D) content delivery networking

We consider a mobile content delivery network (mCDN) in which a special form of mobile devices designated as caching servers (caching-server device: CSD) can provide the near-by devices with some popular contents on demand via device-to-device (D2D) communication links. On the assumption that mobile CSDs are randomly distributed by a Poisson point process (PPP), an optimization problem is formulated to determine the probability of storing the individual content in each server in a manner that minimizes the average caching failure rate. Further, we present a low-complexity search algorithm, optimum dual-solution searching algorithm (ODSA), for solving this optimization problem. We identify the important characteristics of the optimal caching policies in the mobile environment that would serve as a useful aid in designing an mCDN.