Benefits of cache assignment on degraded broadcast channels

Shirin Saeedi Bidokhti, Michèle Wigger, Aylin Yener

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

    11 Scopus citations

    Abstract

    The degraded K-receiver broadcast channel (BC) is studied when receivers are aided with cache memories. Lower and upper bounds are derived on the capacity-memory tradeoff, i.e., on the largest rate that can be achieved as a function of the receivers' cache sizes. The lower bounds are achieved by two new coding schemes that benefit from non-uniform cache assignment. The paper also provides lower and upper bounds on the global capacity-memory tradeoff of degraded BCs, i.e., on the largest capacity-memory tradeoff that can be attained by optimizing the receivers cache-assignment subject to a total cache memory budget. The bounds coincide when the total cache memory budget is sufficiently small or sufficiently large, with the thresholds depending on the BC statistics. For a small total cache budget M, it is optimal to assign all the cache memory to the weakest receiver. In this regime, the global capacity-memory tradeoff grows as M/D, where D denotes the total number of files in the system. For a large total cache budget, it is optimal to assign a positive cache memory to every receiver, where weaker receivers are assigned larger cache memories than stronger receivers. When the total cache budget M exceeds a threshold, then the global capacity-memory tradeoff grows as 1/K.M/D.A uniform cache-assignment policy is suboptimal.

    Original languageEnglish (US)
    Title of host publication2017 IEEE International Symposium on Information Theory, ISIT 2017
    PublisherInstitute of Electrical and Electronics Engineers Inc.
    Pages1222-1226
    Number of pages5
    ISBN (Electronic)9781509040964
    DOIs
    StatePublished - Aug 9 2017
    Event2017 IEEE International Symposium on Information Theory, ISIT 2017 - Aachen, Germany
    Duration: Jun 25 2017Jun 30 2017

    Publication series

    NameIEEE International Symposium on Information Theory - Proceedings
    Volume0
    ISSN (Print)2157-8095

    Other

    Other2017 IEEE International Symposium on Information Theory, ISIT 2017
    CountryGermany
    CityAachen
    Period6/25/176/30/17

    All Science Journal Classification (ASJC) codes

    • Theoretical Computer Science
    • Information Systems
    • Modeling and Simulation
    • Applied Mathematics

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  • Cite this

    Bidokhti, S. S., Wigger, M., & Yener, A. (2017). Benefits of cache assignment on degraded broadcast channels. In 2017 IEEE International Symposium on Information Theory, ISIT 2017 (pp. 1222-1226). [8006723] (IEEE International Symposium on Information Theory - Proceedings; Vol. 0). Institute of Electrical and Electronics Engineers Inc.. https://doi.org/10.1109/ISIT.2017.8006723