Fundamental Rate-Memory Tradeoff for Coded Caching in Presence of User Inactivity

by   Jialing Liao, et al.

Coded caching utilizes proper file subpacketization and coded delivery to make full use of the multicast opportunities in content delivery, to alleviate file transfer load in massive content delivery scenarios. Most existing work considers deterministic environments. An important practical topic is to characterize the impact of the uncertainty from user inactivity on coded caching. We consider a one server cache-enabled network under homogeneous file and network settings in presence of user inactivity. Unlike random or probabilistic caching studied in the literature, deterministic coded caching is considered, with the objective to minimize the worst-case backhaul load by optimizing the file subpacketization and the caching strategy. First, a coded caching method is used, where each file is split into the same type of fragments labeled using sets with fixed cardinality, and the optimality of the selected cardinality is proved. Optimal file subpacketization by splitting the file into multiple types of fragments labeled with multiple cardinalities is then discussed. We show that the closed-form optimum turns out to be given by a fixed cardinality – optimizing for user inactivity only affects file delivery, cache placement is not affected. A decentralized version is also discussed and analyzed, where each user fills its storage independently at random without centralized coordination, and user inactivity is taken into account in file delivery. Simulation results show that the optimization based centralized coded caching scheme provides performance comparable to the ideal scenario assuming full knowledge of user inactivity in the placement phase, while decentralized caching performs slightly worse against user inactivity.


page 1

page 2

page 3

page 4


Efficient File Delivery for Coded Prefetching in Shared Cache Networks with Multiple Requests Per User

We consider a centralized caching network, where a server serves several...

Decentralized and Online Coded Caching with Shared Caches: Fundamental Limits with Uncoded Prefetching

Decentralized coded caching scheme, introduced by Maddah-Ali and Niesen,...

On the Optimality of Ali-Niesen Decentralized Coded Caching Scheme With and Without Error Correction

The decentralized coded caching was introduced in [M. A. Maddah-Ali and ...

Optimization-based Decentralized Coded Caching for Files and Caches with Arbitrary Size

Existing decentralized coded caching solutions cannot guarantee small lo...

Memory-Rate Tradeoff for Caching with Uncoded Placement under Nonuniform File Popularity

For caching with nonuniform file popularity, we aim to characterize the ...

Asynchronous Coded Caching

Coded caching is a technique that promises huge reductions in network tr...

Delay and Power Consumption Tradeoff in Cache-enabled Dense Small Cell Networks: A Generalized Benders Decomposition Approach

Enabling caching capabilities in dense small cell networks (DSCNs) has a...

Please sign up or login with your details

Forgot password? Click here to reset