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area without any prior 5G service deployment. There
are two typical deployment scenarios: mobility and
Fixed-Wireless Access (FWA). Mobility services are
offered to mobile user devices (UE) while FWA is
offering broadband connectivity over mmW links to
subscriber devices (CPE) installed on subscribers’
properties (typically in sub-urban / rural areas).
The design process in both scenarios starts with
collecting: topographical survey information (e.g.
terrain, buildings map), property information (e.g.
residential, commercial, public venues), and candi-
date cell deployment sites (e.g. telecom towers, util-
ity poles). Then the desired coverage targets are de-
termined for each scenario considering the following
factors:
• 5G Mobility Coverage Targets: this includes
polygons representing the areas with high user
density / traffic. Since the users are mobile, there
is no need for guaranteed service at any particu-
lar location in the polygon. This is a design relief
since existing approximate predictions model can
still be used to guarantee average service across
each polygon.
• 5G FWA Coverage Targets: Since the wireless
link is used to offer broadband services equiv-
alent to wired technologies (e.g. fiber and ca-
ble modems), the guarantee of service per user
is a more stringent requirement in this scenario.
Thus, the service availability for each subscriber
property (residential, or commercial) should be
individually evaluated in the design phase. there
should be at least a CPE installation point on each
target property with guaranteed service connectiv-
ity.
Although applicable to both scenarios, the proposed
solution in this work is optimized more towards the
more challenging problem of 5G-FWA design.
Maintaining low radio mounting height is another
key practical design objective. Depending on CU-
DU split scenario (3GPP, 2018b) a combination of
directional antennas and other radio hardware com-
ponents should be mounted on candidate site loca-
tions, preferably above the foliage (aka clutter line) to
provide connectivity to the surrounding user devices.
These hardware components exert structural loads
such as wind-loading on their bearing structure (Tra-
vanca et al., 2019). The structural load is proportional
to the mounting height, so the higher the mounting
height, the higher structural reinforcement cost (De-
Grasse, 2013). Considering the increased number of
cells in 5G mmW and the height and load limitations
on the cell candidates (such as utility poles), the struc-
tural cost can become prohibitive without controlling
the mounting height in the design phase.
The 5G mmW design problem is a complex inte-
ger programming task whose output includes a set of
cell site coordinates, mounting height and the angular
orientation of antennas.
2.3 LoS Assessment Problem
As stated in Section 2.1, Existence of LoS signal path
between the user devices and the serving radio can
be accounted as a reliable service availability metric.
This evidently becomes a trade-off based on the fact
that the higher the mounting height, the more user lo-
cations with LoS signal path (Haneda et al., 2016).
Hence, a solution to the sophisticated cellular design
problem will depend on solving the following prob-
lem for each cell site candidate:
Problem 1. (LoS Query): For a given cell deploy-
ment coordinate (on XY -plane) and any user location
point (in XYZ-space), compute the minimum radio
mounting height at the cell site (minRMH) to achieve
LoS between the user and the cell radio.
Computing minRMH for every combination of
candidate site location and user point is a prerequisite
to any design decision. Solving Problem 1 requires
very high-resolution Digital Elevation Model (DEM)
of the serving area that come in considerable data vol-
umes. Hence, any solution algorithm should be effi-
cient in terms of computation complexity per query
since this computation can be repeated in several iter-
ations per each cell site candidate through the design
process.
3 SCOPE OF SOLUTION
This section details the required data source and the
process to solve Problem 1, including: geometric
formulation of LoS problem in terms of minRMH
and they elements of the existing and proposed algo-
rithms.
3.1 Creating DEM from LiDAR Data
Light Detection and Ranging (LiDAR) offers com-
prehensive areal survey data with very high reso-
lution suited for accurate LoS assessment. It is a
high-resolution remote sensing technology using the
pulsed laser transceiver typically mounted under an
aircraft to scan the surface below a raster flight path.
Similar in concept to radar technology, the character-
istics of the returned pulses are used to estimate the
coordinates of the reflection points. The output of
raw LiDAR scan is commonly called a point-cloud
Optimized Line-of-Sight Assessment Algorithm for 5G mmW Network Design using LiDAR Information
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