Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Reconfigurable Intelligent Surface Aided Constant-Envelope Wireless
  Power Transfer   By reconfiguring the propagation environment of electromagnetic waves
artificially, reconfigurable intelligent surfaces (RISs) have been regarded as
a promising and revolutionary hardware technology to improve the energy and
spectrum efficiency of wireless networks. In this paper, we study a RIS aided
multiuser multiple-input multiple-output (MIMO) wireless power transfer (WPT)
system, where the transmitter is equipped with a constant-envelope analog
beamformer. First, we maximize the total received power of the users by jointly
optimizing the beamformer at transmitter and the phase-shifts at the RIS, and
propose two alternating optimization based suboptimal solutions by leveraging
the semidefinite relaxation (SDR) and the successive convex approximation (SCA)
techniques respectively. Then, considering the user fairness, we formulate
another problem to maximize the total received power subject to the users'
individual minimum received power constraints. A low complexity iterative
algorithm based on both alternating direction method of multipliers (ADMM) and
SCA techniques is proposed to solve this problem. In the case of multiple
users, we further analyze the asymptotic performance as the number of RIS
elements approaches infinity, and bound the performance loss caused by RIS
phase quantization. Numerical results show the correctness of the analysis
results and the effectiveness of the proposed algorithms.

12
The categories of this paper are: nucl-th
11
The categories of this paper are: hep-lat
20
The categories of this paper are: acc-phys
36
The categories of this paper are: cmp-lg
23
The categories of this paper are: solv-int
21
The categories of this paper are: adap-org
32
The categories of this paper are: atom-ph
13
The categories of this paper are: quant-ph
24
The categories of this paper are: dg-ga
28
The categories of this paper are: alg-geom
25
The categories of this paper are: patt-sol
35
The categories of this paper are: mtrl-th
6
The categories of this paper are: astro-ph
16
The categories of this paper are: stat
14
The categories of this paper are: math-ph
37
The categories of this paper are: supr-con