Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: FemtoCaching: Wireless Video Content Delivery through Distributed
  Caching Helpers   Video on-demand streaming from Internet-based servers is becoming one of the
most important services offered by wireless networks today. In order to improve
the area spectral efficiency of video transmission in cellular systems, small
cells heterogeneous architectures (e.g., femtocells, WiFi off-loading) are
being proposed, such that video traffic to nomadic users can be handled by
short-range links to the nearest small cell access points (referred to as
"helpers"). As the helper deployment density increases, the backhaul capacity
becomes the system bottleneck. In order to alleviate such bottleneck we propose
a system where helpers with low-rate backhaul but high storage capacity cache
popular video files. Files not available from helpers are transmitted by the
cellular base station. We analyze the optimum way of assigning files to the
helpers, in order to minimize the expected downloading time for files. We
distinguish between the uncoded case (where only complete files are stored) and
the coded case, where segments of Fountain-encoded versions of the video files
are stored at helpers. We show that the uncoded optimum file assignment is
NP-hard, and develop a greedy strategy that is provably within a factor 2 of
the optimum. Further, for a special case we provide an efficient algorithm
achieving a provably better approximation ratio of $1-(1-1/d)^d$, where $d$ is
the maximum number of helpers a user can be connected to. We also show that the
coded optimum cache assignment problem is convex that can be further reduced to
a linear program. We present numerical results comparing the proposed schemes.

20
The categories of this paper are: acc-phys
19
The categories of this paper are: eess
29
The categories of this paper are: funct-an
8
The categories of this paper are: hep-ex
23
The categories of this paper are: solv-int
30
The categories of this paper are: q-alg
10
The categories of this paper are: q-bio
14
The categories of this paper are: math-ph
16
The categories of this paper are: stat
28
The categories of this paper are: alg-geom
35
The categories of this paper are: mtrl-th
4
The categories of this paper are: cond-mat
12
The categories of this paper are: nucl-th
36
The categories of this paper are: cmp-lg
0
The categories of this paper are: hep-ph
3
The categories of this paper are: physics