Network planning
The use of
deployable and
mobile base
stations is a key
part of Safe-
Net’s approach,
particularly
in terms of
ensuring the
required degree
of resiliency and
redundancy
consultation. Evolved packet cores
(EPCs), eNodeBs, applications and
security are dedicated to PS-LTE, all
are separately implemented for PSLTE.
There will be a full set of core
equipment at each regional operation
centre including EPC, MCPTT,
eMBMS (evolved Multimedia Broadcast
Multicast Service), IMS (IP Multimedia
Subsystem), NMS (network
management system) and common
applications. To be clear, Safe-Net is a
private network.”
Hong concludes by saying that “the
South Korean government is not
planning to implement 5G networks
dedicated for PPDR within four to five
years due to technical and frequency
spectrum characteristics, budget, etc.
As cellular operators have been already
implementing 5G commercial networks
in South Korea, we are studying how
to utilise them in connection with 4G.”
There is much more to missioncritical
network design than the radio
access technology. One issue for TETRA
networks of a certain age is their use
of circuit-switched technology, which
employs time-division multiplexing
(TDM) and synchronous protocols
such as E1 and T1 for the links between
the switches and base stations. If these
are to reap the full benefits of modern
technology – particularly the ability to
use commercial off-the-shelf (COTS)
hardware – such networks need to be
migrated over to internet protocol (IP).
Our next port of call is in Germany,
where the world’s biggest TETRA
network is being upgraded to become an
all-IP system, as BDBOS’s Barbara Held
explains. “This entails a new simplified
architecture that will reduce the number
of switches from 64 to 21 by using new
technical features for virtualisation. At
the same time, all 6,500 base stations
will be upgraded while the network
stays in full operation. The users have
been promised TETRA voice service at
least until 2030.
“In parallel, BDBOS plans to prepare
for basic broadband data services in the
450MHz area, once this spectrum is
allocated to public safety usage. Radio
experts estimate that an additional
1,200-1,500 base stations will be
necessary to establish a broadband
network in these bands that will cover
the entire German territory. The basic
broadband network will deliver the
same mission-critical qualities as the
current TETRA network and will be
used to manage additional capacities in
other bands.”
Adobe Stock/Shariff Che’Lah
of the existing LMR network due to
using a separate 700MHz frequency
band. And LMR sites are not shared
with the PS-LTE sites.” says Young Sam
Hong, outreach committee chair of
Safe-Net Forum. “Therefore, nobody
has reported any coexistence issues.
We are implementing 15,000+ new
sites dedicated to PS-LTE but expect
some coverage shadow areas (such as
underground locations, farming and
fishing villages, and mountains). For
those limited areas we are planning
to also use some of the public
cellular network’s existing eNodeBs
through RAN sharing, this would
improve service quality for the public
safety users”.
He adds that where PS-LTE (public
safety LTE) and commercial networks
share sites, it is mainly the building
facilities, antenna towers and backhaul
that are shared, but “redundancy and
security are separately implemented”.
“Planning and design has been
carried out by network operators
and industries under the supervision
of the government in South
Korea, and the Safe-Net Forum is
providing technical support including
More broadband services and
capacity will be reached by adding
(unharmonised) bands in the 700MHz
area that were allocated to public
safety in 2018. RAN-sharing with the
commercial providers in neighbouring
bands is also being considered. The
scenario will be complemented by
roaming services acquired from
commercial providers, thus delivering
a state-of-the-art hybrid critical
communications system.
What’s in the toolbox?
Given the highly complex nature of
modern network planning and the
many different (and inter-related)
technical and commercial factors that
have to be considered, it is not a surprise
to see that a number of suppliers
provide tools for public safety network
planning.
Jason Suplita, regional executive
at Ranplan Americas, says that it
offers an all-in-one heterogeneous
network planning, optimisation and
simulation solution for small cells,
DAS and Wi-Fi across indoor and
outdoor environments. The company
provides modern indoor/outdoor
HetNet design capabilities supporting
all connectivity technologies. With the
ability to accurately model coverage
and interference through the use of a
true 3D ray-tracing propagation model,
the Ranplan solution addresses the
complexities associated with designing
modern public safety communications
networks for large venues, campus
settings and theme parks. Accurate
predictions using advanced building
structure modelling from floors and
stairs to tunnels offers the public safety
industry an alternative to traditional
design software that only takes into
account in-building areas or outdoor
areas in a separate manner.
“First-responders require dependable
radio coverage prior to and when
entering any emergency situation.
Precision is key when designing
modern public safety connectivity
within and alongside current public
safety networks. We need to ensure
that we exceed today’s compliance
requirements and be ready to meet
those in the future. Ranplan’s inbuilding
design capabilities coupled
with our outdoor network visualisation
capabilities mean that public safety
organisations have the best possible
chance of understanding where
they have indoor-to-outdoor radio
accessibility,” says Suplita.
30 www.criticalcomms.com September 2019
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