5,179 research outputs found
Caching in Heterogeneous Networks
A promising solution in order to cope with the massive request of wireless data traffic
consists of having replicas of the potential requested content memorized across the
network. In cache-enabled heterogeneous networks, content is pre-fetched close to the
users during network off-peak periods in order to directly serve the users when the
network is congested. In fact, the main idea behind caching is the replacement of
backhaul capacity with storage capabilities, for example, at the edge of the network.
Caching content at the edge of heterogeneous networks not only leads to significantly
reduce the traffic congestion in the backhaul link but also leads to achieve higher
levels of energy efficiency. However, the good performance of a system foresees a deep
analysis of the possible caching techniques. Due to the physical limitation of the caches’
size and the excessive amount of content, the design of caching policies which define
how the content has to be cached and select the likely data to store is crucial.
Within this thesis, caching techniques for storing and delivering the content in
heterogeneous networks are investigated from two different aspects. The first part
of the thesis is focused on the reduction of the power consumption when the cached
content is delivered over an Gaussian interference channel and per-file rate constraints
are imposed. Cooperative approaches between the transmitters in order to mitigate
the interference experienced by the users are analyzed. Based on such approaches, the
caching optimization problem for obtaining the best cache allocation solution (in the
sense of minimizing the average power consumption) is proposed. The second part of
the thesis is focused on caching techniques at packet level with the aim of reducing
the transmissions from the core of an heterogeneous network. The design of caching
schemes based on rate-less codes for storing and delivering the cached content are
proposed. For each design, the placement optimization problem which minimizes the
transmission over the backhaul link is formulated
Cost-Effective Cache Deployment in Mobile Heterogeneous Networks
This paper investigates one of the fundamental issues in cache-enabled
heterogeneous networks (HetNets): how many cache instances should be deployed
at different base stations, in order to provide guaranteed service in a
cost-effective manner. Specifically, we consider two-tier HetNets with
hierarchical caching, where the most popular files are cached at small cell
base stations (SBSs) while the less popular ones are cached at macro base
stations (MBSs). For a given network cache deployment budget, the cache sizes
for MBSs and SBSs are optimized to maximize network capacity while satisfying
the file transmission rate requirements. As cache sizes of MBSs and SBSs affect
the traffic load distribution, inter-tier traffic steering is also employed for
load balancing. Based on stochastic geometry analysis, the optimal cache sizes
for MBSs and SBSs are obtained, which are threshold-based with respect to cache
budget in the networks constrained by SBS backhauls. Simulation results are
provided to evaluate the proposed schemes and demonstrate the applications in
cost-effective network deployment
Caching in Heterogeneous Networks
A promising solution in order to cope with the massive request of wireless data traffic consists of having replicas of the potential requested content memorized across the network.
In cache-enabled heterogeneous networks, content is pre-fetched close to the users during network off-peak periods in order to directly serve the users when the network is congested. Caching content at the edge of heterogeneous networks not only leads to significantly reduce the traffic congestion in the backhaul link but also leads to achieve higher levels of energy efficiency. However, the good performance of a system foresees a deep analysis of the possible caching techniques. Due to the physical limitation of the caches' size and the
excessive amount of content, the design of caching policies which define how the content has to be cached and select the likely data to store is crucial.
Within this thesis, caching techniques for storing and delivering the content in heterogeneous networks are investigated from two different aspects. The first part of the thesis is focused on the reduction of the power consumption when the cached content is delivered over an Gaussian interference channel and per-file rate constraints are imposed. Cooperative approaches between the transmitters in order to mitigate the interference experienced by the users are analyzed. Based on such approaches, the caching optimization problem for obtaining the best cache allocation solution (in the sense of minimizing the average power consumption) is proposed. The second part of the thesis is focused on caching techniques at packet level with the aim of reducing the transmissions from the core of an heterogeneous network. The design of caching schemes based on rate-less codes for storing and delivering the cached content are proposed. For each design, the placement optimization problem which minimizes the transmission over the backhaul link is formulated
Edge-Caching Wireless Networks: Performance Analysis and Optimization
Edge-caching has received much attention as an efficient technique to reduce
delivery latency and network congestion during peak-traffic times by bringing
data closer to end users. Existing works usually design caching algorithms
separately from physical layer design. In this paper, we analyse edge-caching
wireless networks by taking into account the caching capability when designing
the signal transmission. Particularly, we investigate multi-layer caching where
both base station (BS) and users are capable of storing content data in their
local cache and analyse the performance of edge-caching wireless networks under
two notable uncoded and coded caching strategies. Firstly, we propose a coded
caching strategy that is applied to arbitrary values of cache size. The
required backhaul and access rates are derived as a function of the BS and user
cache size. Secondly, closed-form expressions for the system energy efficiency
(EE) corresponding to the two caching methods are derived. Based on the derived
formulas, the system EE is maximized via precoding vectors design and
optimization while satisfying a predefined user request rate. Thirdly, two
optimization problems are proposed to minimize the content delivery time for
the two caching strategies. Finally, numerical results are presented to verify
the effectiveness of the two caching methods.Comment: to appear in IEEE Trans. Wireless Commu
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