Graduate School and Research Center in Digital Sciences

Fundamental limits of coded caching with multiple antennas, shared caches and uncoded prefetching

Parrinello, Emanuele; Unsal, Ayse; Elia, Petros

IEEE Transactions on Information Theory, 25 November 2019

The work explores the fundamental limits of coded caching in the setting where a transmitter with potentially multiple (N0) antennas serves different users that are assisted by a smaller number of caches. Under the assumption of uncoded cache placement, the work derives the exact optimal worst-case delay and DoF, for a broad range of userto-cache association profiles where each such profile describes how many users are helped by each cache. This is achieved by presenting an information-theoretic converse based on index coding that succinctly captures the impact of the user-to-cache association, as well as by presenting a coded caching scheme that optimally adapts to the association profile by exploiting the benefits of encoding across users that share the same cache. The work reveals a powerful interplay between shared caches and multiple senders/antennas, where we can now draw the striking conclusion that, as long as each cache serves at least N0 users, adding a single degree of cache-redundancy can yield a DoF increase equal to N0, while at the same time — irrespective of the profile — going from 1 to N0 antennas reduces the delivery time by a factor of N0. Finally some conclusions are also drawn for the related problem of coded caching with multiple file requests.

Document Doi Bibtex

Title:Fundamental limits of coded caching with multiple antennas, shared caches and uncoded prefetching
Keywords:Caching networks, coded caching, shared caches, delivery rate, uncoded cache placement, index coding, MISO broadcast channel, multiple file requests, network coding.
Type:Journal
Language:English
City:
Date:
Department:Communication systems
Eurecom ref:6136
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Bibtex: @article{EURECOM+6136, doi = {http://dx.doi.org/10.1109/TIT.2019.2955384}, year = {2019}, month = {11}, title = {{F}undamental limits of coded caching with multiple antennas, shared caches and uncoded prefetching}, author = {{P}arrinello, {E}manuele and {U}nsal, {A}yse and {E}lia, {P}etros}, journal = {{IEEE} {T}ransactions on {I}nformation {T}heory, 25 {N}ovember 2019}, url = {http://www.eurecom.fr/publication/6136} }
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