1,573 research outputs found
Optimizing MDS Codes for Caching at the Edge
In this paper we investigate the problem of optimal MDS-encoded cache
placement at the wireless edge to minimize the backhaul rate in heterogeneous
networks. We derive the backhaul rate performance of any caching scheme based
on file splitting and MDS encoding and we formulate the optimal caching scheme
as a convex optimization problem. We then thoroughly investigate the
performance of this optimal scheme for an important heterogeneous network
scenario. We compare it to several other caching strategies and we analyze the
influence of the system parameters, such as the popularity and size of the
library files and the capabilities of the small-cell base stations, on the
overall performance of our optimal caching strategy. Our results show that the
careful placement of MDS-encoded content in caches at the wireless edge leads
to a significant decrease of the load of the network backhaul and hence to a
considerable performance enhancement of the network.Comment: to appear in Globecom 201
Energy Efficiency in Cache Enabled Small Cell Networks With Adaptive User Clustering
Using a network of cache enabled small cells, traffic during peak hours can
be reduced considerably through proactively fetching the content that is most
probable to be requested. In this paper, we aim at exploring the impact of
proactive caching on an important metric for future generation networks,
namely, energy efficiency (EE). We argue that, exploiting the correlation in
user content popularity profiles in addition to the spatial repartitions of
users with comparable request patterns, can result in considerably improving
the achievable energy efficiency of the network. In this paper, the problem of
optimizing EE is decoupled into two related subproblems. The first one
addresses the issue of content popularity modeling. While most existing works
assume similar popularity profiles for all users in the network, we consider an
alternative caching framework in which, users are clustered according to their
content popularity profiles. In order to showcase the utility of the proposed
clustering scheme, we use a statistical model selection criterion, namely
Akaike information criterion (AIC). Using stochastic geometry, we derive a
closed-form expression of the achievable EE and we find the optimal active
small cell density vector that maximizes it. The second subproblem investigates
the impact of exploiting the spatial repartitions of users with comparable
request patterns. After considering a snapshot of the network, we formulate a
combinatorial optimization problem that enables to optimize content placement
such that the used transmission power is minimized. Numerical results show that
the clustering scheme enable to considerably improve the cache hit probability
and consequently the EE compared with an unclustered approach. Simulations also
show that the small base station allocation algorithm results in improving the
energy efficiency and hit probability.Comment: 30 pages, 5 figures, submitted to Transactions on Wireless
Communications (15-Dec-2016
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