Ecole d'ingénieur et centre de recherche en Sciences du numérique

Bridging two extremes: Multi-antenna coded caching with reduced subpacketization and CSIT

Lampiris, Eleftherios; Elia, Petros

SPAWC 2019, 20th IEEE International Workshop on Signal Processing Advances in Wireless Communications, Special Session on Cache-aided Communication Networks, 2-5 July 2019, Cannes, France

Two long-standing bottlenecks of coded caching are the exponentially large file sizes that are needed to achieve a maximal caching gain, and - when multiple transmit antennas are involved - the large CSIT feedback costs needed for such caching gains to materialize. Recent results have addressed these two bottlenecks individually, allowing significant reductions in both. In the Multiple-Input-Single-Output (MISO) BC with $L$ antennas, the subpacketization constraint was shown to be as small as the L-th root of the single-antenna case, while maintaining the full Degrees-of-Freedom performance, but requiring feedback from all active users. On the other hand, another result showed that the feedback cost can be reduced to feedback from only $L$ users, but that method required a very high subpacketization. In this work we make progress towards combining the advantages of both worlds by proposing a near-optimal multiantenna coded caching algorithm that incurs a minimal feedback cost, untangled from the number of users, and simultaneously achieving an exponentially reduced subpacketization compared to the single-stream case. In particular - in the context of the L-antenna MISO BC with $K$ single-antenna receivers equipped with caches of normalized size $\gamma$ - the new algorithm achieves a DoF of $(L+K\gamma)(1-\gamma)$ using feedback from only $L$ users, while also reducing subpacketization by a multiplicative factor of $\left(\frac{L+K\gamma}{1+K\gamma}\right)^{K\gamma}$ compared to the single-antenna case, achieving subpacketization reductions exponential to the number of antennas.

Document Doi Bibtex

Titre:Bridging two extremes: Multi-antenna coded caching with reduced subpacketization and CSIT
Type:Conférence
Langue:English
Ville:Cannes
Pays:FRANCE
Date:
Département:Systèmes de Communication
Eurecom ref:5880
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Bibtex: @inproceedings{EURECOM+5880, doi = {http://dx.doi.org/10.1109/SPAWC.2019.8815564}, year = {2019}, title = {{B}ridging two extremes: {M}ulti-antenna coded caching with reduced subpacketization and {CSIT}}, author = {{L}ampiris, {E}leftherios and {E}lia, {P}etros}, booktitle = {{SPAWC} 2019, 20th {IEEE} {I}nternational {W}orkshop on {S}ignal {P}rocessing {A}dvances in {W}ireless {C}ommunications, {S}pecial {S}ession on {C}ache-aided {C}ommunication {N}etworks, 2-5 {J}uly 2019, {C}annes, {F}rance}, address = {{C}annes, {FRANCE}}, month = {07}, url = {http://www.eurecom.fr/publication/5880} }
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