Generalized Degrees of Freedom of the Symmetric Cache-Aided MISO Broadcast Channel With Partial CSIT

Enrico Piovano, Hamdi Joudeh, Bruno Clerckx

Research output: Contribution to journalArticleAcademicpeer-review

2 Citations (Scopus)

Abstract

We consider the cache-aided MISO broadcast channel (BC) in which a multi-antenna transmitter serves K single-antenna receivers, each equipped with a cache memory. The transmitter has access to partial knowledge of the channel state information. For a symmetric setting, in terms of channel strength levels, partial channel knowledge levels and cache sizes, we characterize the generalized degrees of freedom (GDoF) up to a constant multiplicative factor. The achievability scheme exploits the interplay between spatial multiplexing gains and coded-multicasting gain. On the other hand, a cut-set-based argument in conjunction with a GDoF outer bound for a parallel MISO BC under channel uncertainty is used for the converse. We further show that the characterized order-optimal GDoF is also attained in a decentralized setting, where no coordination is required for content placement in the caches.
Original languageEnglish
Article number2914204
Pages (from-to)5799-5815
Number of pages17
JournalIEEE Transactions on Information Theory
Volume65
Issue number9
DOIs
Publication statusPublished - Sep 2019
Externally publishedYes

Keywords

  • Cache-aided interference management
  • Channel state information at the transmitter
  • Coded caching

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