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The most commonly used setting in the coded caching literature consists of the following four elements: (i) homogeneous file sizes, (ii) homogeneous cache sizes, (iii) user-independent homogeneous file popularity (i.e., all users share the same file preference), and (iv) worst-case rate analysis. While recent results have relaxed some of these assumptions, deeper understanding of the full heterogeneity setting is still much needed since traditional caching schemes place little assumptions on file/cache sizes and almost always allow each user to have his/her own file preference through individualized file request prediction. Taking a microscopic approach, this paper characterizes the exact capacity of the smallest 2-user/2-file (N = K = 2) problem but under the most general setting that simultaneously allows for (i) heterogeneous files sizes, (ii) heterogeneous cache sizes, (iii) user-dependent file popularity, and (iv) average-rate analysis. Solving completely the case of N = K = 2 could shed further insights on the performance and complexity of optimal coded caching with full heterogeneity for arbitrary N and K.
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Cache-Aided Two-User Broadcast Channels with State Information at Receivers
A two-user coded caching problem is studied in a joint source-channel coding framework. A source generates symbols at a certain rate for each file in the database, and a fixed fraction of the symbols are cached at each user. The delivery phase of coded caching takes place over a time-varying erasure broadcast channel, where the channel state information is only available at the receivers. The maximum source rate to keep up with the ergodic rate of both users is characterized.
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- Award ID(s):
- 1749981
- PAR ID:
- 10164735
- Date Published:
- Journal Name:
- 2019 IEEE International Symposium on Information Theory (ISIT)
- Page Range / eLocation ID:
- 16 to 20
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1109/ISIT.2019.8849820
