Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Joint Design of Digital and Analog Processing for Downlink C-RAN with
  Large-Scale Antenna Arrays   In millimeter-wave communication systems with large-scale antenna arrays,
conventional digital beamforming may not be cost-effective. A promising
solution is the implementation of hybrid beamforming techniques, which consist
of low-dimensional digital beamforming followed by analog radio frequency (RF)
beamforming. This work studies the optimization of hybrid beamforming in the
context of a cloud radio access network (C-RAN) architecture. In a C-RAN
system, digital baseband signal processing functionalities are migrated from
remote radio heads (RRHs) to a baseband processing unit (BBU) in the "cloud" by
means of finite-capacity fronthaul links. Specifically, this work tackles the
problem of jointly optimizing digital beamforming and fronthaul quantization
strategies at the BBU, as well as RF beamforming at the RRHs, with the goal of
maximizing the weighted downlink sum-rate. Fronthaul capacity and per-RRH power
constraints are enforced along with constant modulus constraints on the RF
beamforming matrices. An iterative algorithm is proposed that is based on
successive convex approximation and on the relaxation of the constant modulus
constraint. The effectiveness of the proposed scheme is validated by numerical
simulation results.

32
The categories of this paper are: atom-ph
29
The categories of this paper are: funct-an
12
The categories of this paper are: nucl-th
13
The categories of this paper are: quant-ph
9
The categories of this paper are: nlin
24
The categories of this paper are: dg-ga
6
The categories of this paper are: astro-ph
18
The categories of this paper are: econ
10
The categories of this paper are: q-bio
0
The categories of this paper are: hep-ph
5
The categories of this paper are: gr-qc
23
The categories of this paper are: solv-int
19
The categories of this paper are: eess
4
The categories of this paper are: cond-mat
28
The categories of this paper are: alg-geom
3
The categories of this paper are: physics