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Content Delivery in Fog-Aided Small-Cell Systems with Offline and Online Caching: An Information--Theoretic Analysis.
- Source :
- Entropy; Jul2017, Vol. 19 Issue 7, p366, 23p
- Publication Year :
- 2017
-
Abstract
- The storage of frequently requested multimedia content at small-cell base stations (BSs) can reduce the load of macro-BSs without relying on high-speed backhaul links. In this work, the optimal operation of a system consisting of a cache-aided small-cell BS and a macro-BS is investigated for both offline and online caching settings. In particular, a binary fading one-sided interference channel is considered in which the small-cell BS, whose transmission is interfered by the macro-BS, has a limited-capacity cache. The delivery time per bit (DTB) is adopted as a measure of the coding latency, that is, the duration of the transmission block, required for reliable delivery. For offline caching, assuming a static set of popular contents, the minimum achievable DTB is characterized through information-theoretic achievability and converse arguments as a function of the cache capacity and of the capacity of the backhaul link connecting cloud and small-cell BS. For online caching, under a time-varying set of popular contents, the long-term (average) DTB is evaluated for both proactive and reactive caching policies. Furthermore, a converse argument is developed to characterize the minimum achievable long-term DTB for online caching in terms of the minimum achievable DTB for offline caching. The performance of both online and offline caching is finally compared using numerical results. [ABSTRACT FROM AUTHOR]
- Subjects :
- CODING theory
INTERFERENCE (Aerodynamics)
Subjects
Details
- Language :
- English
- ISSN :
- 10994300
- Volume :
- 19
- Issue :
- 7
- Database :
- Complementary Index
- Journal :
- Entropy
- Publication Type :
- Academic Journal
- Accession number :
- 124336524
- Full Text :
- https://doi.org/10.3390/e19070366