Content Delivery in Erasure Broadcast Channels With Cache and Feedback

Ghorbel, Asma; Kobayashi, Mari; Yang, Sheng

doi:10.1109/tit.2016.2605123

Cited by 45 publications

(46 citation statements)

References 34 publications

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“…3) Impact of encoding over users that share the same cache: As we know, both the MN algorithm in [1] and the multi-antenna algorithm in [38], are designed for users with different caches, so -in the uniform case where L λ = K/Λ -one conceivable treatment of the sharedcache problem would have been to apply these algorithms over Λ users at a time, all with different caches 10 . As we see, in the single antenna case, this implementation would treat 1 + Λγ users at a time thus yielding a delay of T = K(1−γ) 1+Λγ , while in the multi-antenna case, this implementation would treat N 0 + Λγ users at a time (see [38]) thus yielding a delay of T = K(1−γ) N0+Λγ .…”

Section: )mentioning

confidence: 99%

Optimal coded caching in heterogeneous networks with uncoded prefetching

Parrinello

Ünsal

Elia

2018

2018 IEEE Information Theory Workshop (ITW)

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The work explores the fundamental limits of coded caching in heterogeneous networks where multiple (N0) senders/antennas, serve different users which are associated (linked) to shared caches, where each such cache helps an arbitrary number of users. Under the assumption of uncoded cache placement, the work derives the exact optimal worstcase delay and DoF, for a broad range of user-to-cache association profiles where each such profile describes how many users are helped by each cache. This is achieved by presenting an information-theoretic converse based on index coding that succinctly captures the impact of the user-to-cache association, as well as by presenting a coded caching scheme that optimally adapts to the association profile by exploiting the benefits of encoding across users that share the same cache.The work reveals a powerful interplay between shared caches and multiple senders/antennas, where we can now draw the striking conclusion that, as long as each cache serves at least N0 users, adding a single degree of cache-redundancy can yield a DoF increase equal to N0, while at the same time -irrespective of the profile -going from 1 to N0 antennas reduces the delivery time by a factor of N0. Finally some conclusions are also drawn for the related problem of coded caching with multiple file requests.

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Section: )mentioning

confidence: 99%

Optimal coded caching in heterogeneous networks with uncoded prefetching

Parrinello

Ünsal

Elia

2018

2018 IEEE Information Theory Workshop (ITW)

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“…In Fig. 3, we compare the delivery load R * A,D (m) obtained from optimization problem (18), with the lower bounds on R * (m) in (21), (22), and the lower bound with uncoded placement in (19), for N = K = 5 and m k = 0.95 m k+1 . From Fig.…”

Section: Delivery Phase: We Have the Following Transmissionsmentioning

confidence: 99%

Coded Caching for Heterogeneous Systems: An Optimization Perspective

Ibrahim

Zewail

Yener

2019

IEEE Trans. Commun.

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In cache-aided networks, the server populates the cache memories at the users during low-traffic periods, in order to reduce the delivery load during peak-traffic hours. In turn, there exists a fundamental trade-off between the delivery load on the server and the cache sizes at the users. In this paper, we study this trade-off in a multicast network where the server is connected to users with unequal cache sizes and the number of users is less than or equal to the number of library files. We propose centralized uncoded placement and linear delivery schemes which are optimized by solving a linear program. Additionally, we derive a lower bound on the delivery memory trade-off with uncoded placement that accounts for the heterogeneity in cache sizes. We explicitly characterize this trade-off for the case of three end-users, as well as an arbitrary number of end-users when the total memory size at the users is small, and when it is large. Next, we consider a system where the server is connected to the users via rate limited links of different capacities and the server assigns the users' cache sizes subject to a total cache budget. We characterize the optimal cache sizes that minimize the delivery completion time with uncoded placement and linear delivery. In particular, the optimal memory allocation balances between assigning larger cache sizes to users with low capacity links and uniform memory allocation. Index TermsCoded caching, uncoded placement, cache size optimization, multicast networks.This work was presented in part at

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“…In [19] and [20], content delivery over an erasure broadcast channel is considered, while a Gaussian broadcast channel is studied in [21], [22] and [23]. Erasure and Gaussian broadcast delivery channels with feedback are studied in [24] and [25], respectively. Main challenge in these works is to exploit the broadcast channel in a non-trivial manner, that goes beyond reducing the problem to delivery over a shared link whose rate is dictated by the user with the worst channel quality.…”

Section: Introductionmentioning

confidence: 99%

Content Caching and Delivery in Wireless Radio Access Networks

Tao

Gündüz

et al. 2019

IEEE Trans. Commun.

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Today's mobile data traffic is dominated by content-oriented traffic. Caching popular contents at the network edge can alleviate network congestion and reduce content delivery latency. This paper provides a comprehensive and unified study of caching and delivery techniques in wireless radio access networks (RANs) with caches at all edge nodes (ENs) and user equipments (UEs). Three cache-aided RAN architectures are considered: RANs without fronthaul, with dedicated fronthaul, and with wireless fronthaul. It first reviews in a tutorial nature how caching facilitates interference management in these networks by enabling interference cancellation (IC), zero-forcing (ZF), and interference alignment (IA). Then, two new delivery schemes are presented. One is for RANs with dedicated fronthaul, which considers centralized cache placement at the ENs but both centralized and decentralized placement at the UEs. This scheme combines IA, ZF, and IC together with soft-transfer fronthauling. The other is for RANs with wireless fronthaul, which considers decentralized cache placement at all nodes. It leverages the broadcast nature of wireless fronthaul to fetch not only uncached but also cached contents to boost transmission cooperation among the ENs. Numerical results show that both schemes outperform existing results for a wide range of system parameters, thanks to the various caching gains obtained opportunistically. Index TermsCoded caching, delivery time, fog radio access networks, interference alignment, interference cancellation, interference management, wireless edge caching, zero-forcing.

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Content Delivery in Erasure Broadcast Channels With Cache and Feedback

Cited by 45 publications

References 34 publications

Optimal coded caching in heterogeneous networks with uncoded prefetching

Optimal coded caching in heterogeneous networks with uncoded prefetching

Coded Caching for Heterogeneous Systems: An Optimization Perspective

Content Caching and Delivery in Wireless Radio Access Networks

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