Learning distributed caching strategies in small cell networks

Avik Sengupta, Saidhiraj Amuru, Ravi Tandon, R. Michael Buehrer, T. Charles Clancy

Research output: Chapter in Book/Report/Conference proceedingConference contribution

96 Scopus citations

Abstract

Caching has emerged as a vital tool in modern communication systems for reducing peak data rates by allowing popular files to be pre-fetched and stored locally at end users' devices. With the shift in paradigm from homogeneous cellular networks to the heterogeneous ones, the concept of data offloading to small cell base stations (sBS) has garnered significant attention. Caching at these small cell base stations has recently been proposed, where popular files are pre-fetched and stored locally in order to avoid bottlenecks in the limited capacity backhaul connection link to the core network. In this paper, we study distributed caching strategies in such a heterogeneous small cell wireless network from a reinforcement learning perspective. Using state of the art results, it can be shown that the optimal joint cache content placement in the sBSs turns out to be a NP-hard problem even when the sBS's are aware of the popularity profile of the files that are to be cached. To address this problem, we propose a coded caching framework, where the sBSs learn the popularity profile of the files (based on their demand history) via a combinatorial multi-armed bandit framework. The sBSs then pre-fetch segments of the Fountain-encoded versions of the popular files at regular intervals to serve users' requests. We show that the proposed coded caching framework can be modeled as a linear program that takes into account the network connectivity and thereby jointly designs the caching strategies. Numerical results are presented to show the benefits of the joint coded caching technique over naive decentralized cache placement strategies.

Original languageEnglish (US)
Title of host publication2014 11th International Symposium on Wireless Communications Systems, ISWCS 2014 - Proceedings
PublisherInstitute of Electrical and Electronics Engineers Inc.
Pages917-921
Number of pages5
ISBN (Electronic)9781479958634
DOIs
StatePublished - Oct 21 2014
Externally publishedYes
Event2014 11th International Symposium on Wireless Communications Systems, ISWCS 2014 - Barcelona, Spain
Duration: Aug 26 2014Aug 29 2014

Publication series

Name2014 11th International Symposium on Wireless Communications Systems, ISWCS 2014 - Proceedings

Conference

Conference2014 11th International Symposium on Wireless Communications Systems, ISWCS 2014
Country/TerritorySpain
CityBarcelona
Period8/26/148/29/14

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Computer Networks and Communications

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