5,048 research outputs found
Combinatorial Multi-Access Coded Caching: Improved Rate-Memory Trade-off with Coded Placement
This work considers the combinatorial multi-access coded caching problem
introduced in the recent work by Muralidhar \textit{et al.} [P. N. Muralidhar,
D. Katyal, and B. S. Rajan, ``Maddah-Ali-Niesen scheme for multi-access coded
caching,'' in \textit{IEEE Inf. Theory Workshop (ITW)}, 2021] The problem
setting consists of a central server having a library of files and
caches each of capacity . Each user in the system can access a unique set of
caches, and there exist users corresponding to every distinct set of
caches. Therefore, the number of users in the system is . For the
aforementioned combinatorial multi-access setting, we propose a coded caching
scheme with an MDS code-based coded placement. This novel placement technique
helps to achieve a better rate in the delivery phase compared to the optimal
scheme under uncoded placement, when . For a lower memory regime, we
present another scheme with coded placement, which outperforms the optimal
scheme under uncoded placement if the number of files is no more than the
number of users. Further, we derive an information-theoretic lower bound on the
optimal rate-memory trade-off of the combinatorial multi-access coded caching
scheme. Finally, using the derived lower bound, we show that the first scheme
is optimal in the higher memory regime, and the second scheme is optimal if
.Comment: 15 pages and 5 figure
Cache-Aided Coded Multicast for Correlated Sources
The combination of edge caching and coded multicasting is a promising
approach to improve the efficiency of content delivery over cache-aided
networks. The global caching gain resulting from content overlap distributed
across the network in current solutions is limited due to the increasingly
personalized nature of the content consumed by users. In this paper, the
cache-aided coded multicast problem is generalized to account for the
correlation among the network content by formulating a source compression
problem with distributed side information. A correlation-aware achievable
scheme is proposed and an upper bound on its performance is derived. It is
shown that considerable load reductions can be achieved, compared to state of
the art correlation-unaware schemes, when caching and delivery phases
specifically account for the correlation among the content files.Comment: In proceeding of IEEE International Symposium on Turbo Codes and
Iterative Information Processing (ISTC), 201
Multi-Antenna Coded Caching
In this paper we consider a single-cell downlink scenario where a
multiple-antenna base station delivers contents to multiple cache-enabled user
terminals. Based on the multicasting opportunities provided by the so-called
Coded Caching technique, we investigate three delivery approaches. Our baseline
scheme employs the coded caching technique on top of max-min fair multicasting.
The second one consists of a joint design of Zero-Forcing (ZF) and coded
caching, where the coded chunks are formed in the signal domain (complex
field). The third scheme is similar to the second one with the difference that
the coded chunks are formed in the data domain (finite field). We derive
closed-form rate expressions where our results suggest that the latter two
schemes surpass the first one in terms of Degrees of Freedom (DoF). However, at
the intermediate SNR regime forming coded chunks in the signal domain results
in power loss, and will deteriorate throughput of the second scheme. The main
message of our paper is that the schemes performing well in terms of DoF may
not be directly appropriate for intermediate SNR regimes, and modified schemes
should be employed.Comment: 7 pages, 2 figure
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