Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Location-based Initial Access for Wireless Power Transfer with
  Physically Large Arrays   Radio frequency (RF) wireless power transfer (WPT) is a promising technology
for 6G use cases. It enables a massive, yet sustainable deployment of
batteryless energy neutral (EN) devices at unprecedented scale. Recent research
on 6G is exploring high operating frequencies up to the THz spectrum, where
antenna arrays with large apertures are capable of forming narrow, "laser-like"
beams. At sub-10 GHz frequencies, physically large antenna arrays are
considered that are operating in the array near field. Transmitting spherical
wavefronts, power can be focused in a focal point rather than a beam, which
allows for efficient and radiation-safe WPT. We formulate a multipath channel
model comprising specular components and diffuse scattering to find the WPT
power budget in a realistic indoor scenario. Specular components can be
predicted by means of a geometric model. This is used to transmit power via
multiple beams simultaneously, increasing the available power budget and
expanding the initial access distance. We show that exploiting this "beam
diversity" reduces the required fading margin for the initial access to EN
devices.

29
The categories of this paper are: funct-an
7
The categories of this paper are: hep-th
37
The categories of this paper are: supr-con
2
The categories of this paper are: math
11
The categories of this paper are: hep-lat
14
The categories of this paper are: math-ph
31
The categories of this paper are: ao-sci
13
The categories of this paper are: quant-ph
16
The categories of this paper are: stat
15
The categories of this paper are: nucl-ex
22
The categories of this paper are: chao-dyn
1
The categories of this paper are: cs
32
The categories of this paper are: atom-ph
4
The categories of this paper are: cond-mat
12
The categories of this paper are: nucl-th
34
The categories of this paper are: chem-ph