5,593 research outputs found
A Delay-Aware Caching Algorithm for Wireless D2D Caching Networks
Recently, wireless caching techniques have been studied to satisfy lower
delay requirements and offload traffic from peak periods. By storing parts of
the popular files at the mobile users, users can locate some of their requested
files in their own caches or the caches at their neighbors. In the latter case,
when a user receives files from its neighbors, device-to-device (D2D)
communication is enabled. D2D communication underlaid with cellular networks is
also a new paradigm for the upcoming 5G wireless systems. By allowing a pair of
adjacent D2D users to communicate directly, D2D communication can achieve
higher throughput, better energy efficiency and lower traffic delay. In this
work, we propose a very efficient caching algorithm for D2D-enabled cellular
networks to minimize the average transmission delay. Instead of searching over
all possible solutions, our algorithm finds out the best pairs,
which provide the best delay improvement in each loop to form a caching policy
with very low transmission delay and high throughput. This algorithm is also
extended to address a more general scenario, in which the distributions of
fading coefficients and values of system parameters potentially change over
time. Via numerical results, the superiority of the proposed algorithm is
verified by comparing it with a naive algorithm, in which all users simply
cache their favorite files
Echo State Networks for Proactive Caching in Cloud-Based Radio Access Networks with Mobile Users
In this paper, the problem of proactive caching is studied for cloud radio
access networks (CRANs). In the studied model, the baseband units (BBUs) can
predict the content request distribution and mobility pattern of each user,
determine which content to cache at remote radio heads and BBUs. This problem
is formulated as an optimization problem which jointly incorporates backhaul
and fronthaul loads and content caching. To solve this problem, an algorithm
that combines the machine learning framework of echo state networks with
sublinear algorithms is proposed. Using echo state networks (ESNs), the BBUs
can predict each user's content request distribution and mobility pattern while
having only limited information on the network's and user's state. In order to
predict each user's periodic mobility pattern with minimal complexity, the
memory capacity of the corresponding ESN is derived for a periodic input. This
memory capacity is shown to be able to record the maximum amount of user
information for the proposed ESN model. Then, a sublinear algorithm is proposed
to determine which content to cache while using limited content request
distribution samples. Simulation results using real data from Youku and the
Beijing University of Posts and Telecommunications show that the proposed
approach yields significant gains, in terms of sum effective capacity, that
reach up to 27.8% and 30.7%, respectively, compared to random caching with
clustering and random caching without clustering algorithm.Comment: Accepted in the IEEE Transactions on Wireless Communication
GreenDelivery: Proactive Content Caching and Push with Energy-Harvesting-based Small Cells
The explosive growth of mobile multimedia traffic calls for scalable wireless
access with high quality of service and low energy cost. Motivated by the
emerging energy harvesting communications, and the trend of caching multimedia
contents at the access edge and user terminals, we propose a paradigm-shift
framework, namely GreenDelivery, enabling efficient content delivery with
energy harvesting based small cells. To resolve the two-dimensional randomness
of energy harvesting and content request arrivals, proactive caching and push
are jointly optimized, with respect to the content popularity distribution and
battery states. We thus develop a novel way of understanding the interplay
between content and energy over time and space. Case studies are provided to
show the substantial reduction of macro BS activities, and thus the related
energy consumption from the power grid is reduced. Research issues of the
proposed GreenDelivery framework are also discussed.Comment: 15 pages, 5 figures, accepted by IEEE Communications Magazin
- …