Network Resilience
Network resilience and
redundancy planning
Private PMR public safety networks are designed to be highly resilient, but the migration
of critical communications users onto commercial 4G networks increases the complexity
of planning for resilience. Richard Martin looks at how it can be achieved
Public safety networks need to be resilient during
man-made problems, from the digging up of
a cable to a major natural disaster such as an
earthquake. In the latter case, this will be exactly
the time the service is most needed. Planning
for and building network resilience is vital if the service
is to meet its objectives and keep the general public and
emergency services safe and effective.
Resilience measures can be implemented in all parts of
the radio network, including its primary elements, power
supply, links redundancy and switching back-up solutions.
Such measures are commonly found in PMR networks, but
now ‘best effort’ commercial 4G/LTE networks looking to
host mission-critical communications users are having to
step up to meet these users’ more exacting requirements.
Base station resilience and backhaul
Kevin Humphries, market specialist – TETRA infrastructure
at Motorola Solutions, has been involved in numerous
TETRA projects around the world. Starting with power
supply, he says: “We have been using a range of solutions
for power, either as back-up for mains or as alternatives.
Battery back-up is common on conventional sites, but we
have provided diesel generators on remote sites where mains
is not available.
“In the Middle East we have provided a combined solar
and battery combination, and have seen some customers
use oil or natural gas generators along pipelines with a
feed of fuel from the pipeline itself. I am also aware of a
hydroelectric-powered base station in Iceland. In Norway,
we have used hydrogen fuel cells. These are an eco-friendly
solution, but expensive.”
How much back-up time should be provisioned with
batteries? “That depends, it relates to the importance of
the site. For example, is it the only one in the area? Also,
its accessibility – is it difficult to reach to replace batteries
or deploy a temporary generator? In some cases, it may be
necessary to provision months or even a year of fuel if the
Continuity of
power supply is
a key resilience
measure;
batteries, diesel
generators and
solar power are all
used for failover
power generation
March 2020 @CritCommsToday 31