Exploiting mobility in cache-assisted D2D networks: Performance analysis and optimization

Rui Wang, Jun Zhang, S. H. Song, Khaled B. Letaief

Research output: Journal article publicationJournal articleAcademic researchpeer-review

34 Citations (Scopus)


Caching popular content at mobile devices, accompanied by device-to-device (D2D) communications, is one promising technology for effective mobile content delivery. User mobility is an important factor when investigating such networks, which unfortunately was largely ignored in most previous works. Preliminary studies have been carried out but the effect of mobility on the caching performance has not been fully understood. In this paper, by explicitly considering users' contact and inter-contact durations via an alternating renewal process, we first investigate the effect of mobility with a given cache placement. A tractable expression of the data offloading ratio, i.e., the proportion of requested data that can be delivered via D2D links, is derived, which is proved to be increasing with the user moving speed. The analytical results are then used to develop an effective mobility-aware caching strategy to maximize the data offloading ratio. Simulation results are provided to confirm the accuracy of the analytical results and also validate the effect of user mobility. Performance gains of the proposed mobility-aware caching strategy are demonstrated with both stochastic models and real-life data sets. It is observed that the information of the contact durations is critical to design cache placement, especially when they are relatively short or comparable to the inter-contact durations.

Original languageEnglish
Article number8393473
Pages (from-to)5592-5605
Number of pages14
JournalIEEE Transactions on Wireless Communications
Issue number8
Publication statusPublished - Aug 2018
Externally publishedYes


  • Device-to-device communications
  • Human mobility
  • Renewal process
  • Wireless caching

ASJC Scopus subject areas

  • Computer Science Applications
  • Electrical and Electronic Engineering
  • Applied Mathematics


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