Improving efficiency and making cost savings are constant demands upon public safety organisations everywhere. At the same time, advances in mobile connectivity have changed the landscape dramatically. The boom of smartphones has driven understanding and usage of wireless internet. TETRA has served well until now, but its low bandwidth data solutions do not meet modern demands. It is difficult to understand why an expensive public safety vehicle should not have the same or better capabilities than the average teenager carries in their pocket. Efficient modern public safety organisations demand access to databases like patient records, criminal registers, stolen car registers and even building plans. It is crucial that used data remains always up to date and easily accessible, otherwise our security and health becomes compromised. Other modern applications are needed both now and in the near future. Secure video streaming is currently the most wanted application. All modern PSS services require secure, resilient ‘always online’ connectivity with built in redundancy.

1. Goodmill White Paper
Public Safety Mobile Data Development

2. Goodmill Systems Ltd.
Sinikalliontie 10 FI-02630 Espoo, Finland
www.goodmillsystems.com
Page 2
Improving efficiency and making cost savings are constant demands
upon public safety organisations everywhere. At the same time,
advances in mobile connectivity have changed the landscape
dramatically. The boom of smartphones has driven understanding
and usage of wireless internet. TETRA has served well until now, but
its low bandwidth data solutions do not meet modern demands. It is
difficult to understand why an expensive public safety vehicle should
not have the same or better capabilities than the average teenager
carries in their pocket.
Efficient modern public safety organisations demand access to
databases like patient records, criminal registers, stolen car registers and
even building plans. It is crucial that used data remains always up to
date and easily accessible, otherwise our security and health becomes
compromised. Other modern applications are needed both now and in
the near future. Secure video streaming is currently the most wanted
application. All modern PSS services require secure, resilient ‘always
online’ connectivity with built in redundancy.
Public Safety Broadband
Network Development
The driving force behind PSS broadband network development is LTE
technology and the myriad possibilities it provides. There are many
approaches and different methods of development, but all share the
idea that ultimately all communication in PSS will be done over high data
rate IP networks.1
The first option is to build a dedicated network for the PS sector. The
benefits of this solution are full control over the network, flexibility
to change and adapt as needed and a dedicated capacity. The major
disadvantages are high cost and long development time. There is also
a question mark over whether or not the final coverage and availability
meets the required demand and represents good value for money.
The second option would be to build a dedicated radio access network
only. In this scenario the PS would build their own base stations,
relying on a commercial core. The benefits would be that PS could
specify the RAN requirements and would have dedicated RAN capacity.
Disadvantages are the costs of building the RAN network despite the
savings in the core.
The third option would be to assign dedicated channels for commercial
networks. Benefits of this are an assured RAN capacity that would be
provided cost efficiently. Future flexibility of the solution in the pressure
of commercial networks could be challenged. To ensure the demands of
critical communications, close co-operation with the commercial carriers
would be a requirement.
The fourth option is based on an enterprise-type approach. In this case the
network would be fully shared but there would be a special service layer
implementation. This would provide high cost efficiency and flexibility
in service level agreements. A disadvantage to this would be that this
solution has limited capability of guaranteeing dedicated capacity to PS
users.
The fifth and most service orientated approach is a fully shared retail
network. This would be highly cost efficient, simple to operate and can
be implemented immediately. Disadvantages include the inability to give
dedicated capacities, less service flexibility and possibly higher per user
fees.
Land Mobile Network Influence
There are already public safety digital solutions for voice and a limited
amount of data that have been implemented worldwide. These TETRA,
Tetrapol, P25 and similar networks often have wide coverage areas, but
simultaneously bear significant costs to today’s operations. This raises
the following questions:
What is the future network model for broadband data?
What is the role of installed digital LMR networks?
What is the migration path in order to converge mission critical voice
and data?
One view on the drivers behind this transformation is illustrated in a
document by the US Department of Homeland Security.
The diagram illustrates the current status of the PS vehicle
communications and shows a possible transition path from the current
system through to the ultimate evolution of the service.2
The sector currently uses many applications that make demands upon
the limited bandwidth of the Land Mobile Networks’ data capacities.
Public Safety Mobile Data Development
1 The Public Safety Broadband Wireless Network: 21st Century
Communications for First Responders Public Safety Homeland Security Bureau
Federal Communications Commission. Tuesday, March 9, 2010. 2 Public Safety Communications Evolution, November 2011, US Department of Homeland Security.

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All mission critical data is carried over the LMR networks while demand
for more bandwidth continues to rise, hence the discussion around
transitional dedicated networks.
The data applications for PS need to meet the requirements of criticality.
This requirement is the imperative in creating the solution. Knowing this,
one needs to remember that no single network, dedicated or commercial,
is always secure.
Filling the Gap Today
Looking closely at what the general requirements are in this area, we
can see from the alternatives discussed earlier that funding is the
major influencing factor in PS network development. Given the current
global economic situation, it would be unreasonable to expect that any
country would build either its own dedicated broadband networks or
the access networks required for the coverage of critical operations. The
alternatives of implementing dedicated channels or service layers seem
more appropriate fiscally. This approach however, requires a creation of
policies, partnerships and planning that demand some lead times. They
also require research, development and testing and the associated costs.
These are still possibilities, and these kind of approaches will certainly
provide paths towards future implementations.
The fifth alternative of using existing commercial networks is the easiest to
implement, but questions remain over the most important requirements of
future services. Will commercial networks ever fulfill the demands of critical
PS data? If we could overcome the challenges of guaranteed access, quality
of service, reliability, resiliency, interoperability, spectrum efficiency and high
availability using current networks, we could use pre-existing solutions for
mission critical data. This would also mean that no transitional network
phase would be needed.
Multiple Network Approach
Most of the challenges faced can be tackled smartly by using not one,
but several networks for data. By combining dedicated and commercial,
readily available networks, access can be improved significantly.
Reliability and resiliency is no longer reliant upon a single network, but
an independent combination. Availability and quality of service are what
operators can jointly offer. The network infrastructure providers will
naturally develop the spectrum efficiency to maximise the efficiency of
their own networks, while roaming could be provided between networks,
ensuring the best available is always used.
What do these combined networks have to offer in practice? The main
challenge in moving vehicles is maintaining connectivity, being ‘always
online’. Recent studies show as low as 70% availability for any single 3G
network, even in the best coverage areas.
Table 1. Example of single and multiple broadband network availability.3
The sort of availability required for PS broadband is ~99%. It is clear
that providing that kind of availability over bespoke dedicated networks
incorporates huge costs when applied over a larger region. It is
understandable that the single carrier approach with its low availabilities
is also not sufficient. However, when combining even two networks
with availabilities as low as 64% and 76% separately, the combined
availability is over 99%! Introducing a third network enhances this figure
further.
When the switch over from one network to another is seamless, it can be
claimed that this approach provides the needed technical functionality
that is acceptable for critical communications today.
So why isn’t this approach used more widely today? The reason is that
this solution requires router equipment with very special features that
are unmet by established router manufacturers today.
Overall Picture of the
Needed Router Solution
The router solution needed for critical data, independent of which
solution is required, thus needs to include the smart usage of multiple
networks. The more flexible the WAN link configuration used, the
more flexibility, reliability, resilience and security can be provided. The
router solution must include a wide variety of links, top class encryption
capabilities, fast switching between networks, the possibility to be
remotely managed and to give a constant overview of the connectivity.
The system needs to be able to provide a seamless service to vehicles
that include, but are not limited to:
• Image and file transfer
• Database queries
• Location based services
• Biometric checks
• Streaming video
These services can be used in a critical environment only by routers
that are specifically designed for the purpose. This includes software,
hardware and management features.
Router Software Requirements
The most important software feature for the router system is the
capability to use multiple networks seamlessly, without any service
interruptions. Mobile IP (MIP) tunneling implemented by few
manufacturers is a part of the solution. This technology hides the
network changes from the termination point and enables fast switch
over without unnecessary VPN negotiations. These customers always3 Goodmill data from tets in downtown Helsinki, 2011.

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use encrypted traffic, so various levels of VPN tunnels are used by
different user organisations. MIP also guarantees session persistency
so that the users are not required to re-authenticate to their backend
systems every time a link is changed. But MIP cannot handle the fast
switch over on its own.
Current mobile networks are extremely dynamic, and having data
streaming both to and from moving vehicles increases the demand
upon the connection. The networks are mainly designed to serve nomad
customers, so systems that solemnly depend on networks’ routing
capabilities cannot follow a fast moving vehicle. With only protocol
based routing, the switch over decision cannot be made quickly enough.
The only feasible solution is to use predefined routes and predict at all
times the best possible routing for any of the used links. This enhances
the capabilities for decision making when the network switch over is
necessary.
The router software requirements also include the capability of
autonomously controlling the modems used. The modems have a
tendency to stay in a ‘hanging’ mode and appear as if they are connected
to the network, but no data is transmitted. This and other similar
dysfunctions need to be detected by the router, and the software needs
to ‘wake’ the modems up.
Router Hardware Requirements
The market offers several appliance hardware solutions for router
developers. These appliances are not designed to handle the specific
requirements of critical PS communication. The first requirement
is flexibility. When connectivity is introduced to wide areas, it is
often demanded that various routers have quite different hardware
configurations. This is mostly emphasized in the WAN link flexibility. In
many cases two links might be enough to fulfill critical PS demands, but
there are cases where 3 or even 4 links are necessary. These links need to
include all UMTS technologies (3G and 4G), as well as capabilities for all
CDMA based technologies and even satellite connectivity.
Robustness of hardware is a must in these demanding applications.
Although the routers are located inside the vehicles, shock resistance
and IP classification must be high. It is clear that consumer products
or slightly upgraded consumer products will not offer the long term
durability required.
Therouteralsodemandsacarrierclasshardwareapproachwhenitcomes
to software updates. When remote software updates are implemented,
the router must first test it before applying it. This requires dual memory
allocation. Also required is built in software functionality for rolling back
to a previous functioning version in the event of a system malfunction. It
is crucial that the routers are never out of service in the field.
Sometimes,onlysoftwarebasedbootingoftheequipmentisnotenough.
It is of the utmost importance that the hardware has functionality to
mechanically switch the power off. This mechanical power switch,
controlled by the software, is one element of a perfect solution for PS.
Similar functionality is needed in the power back-up. The vehicle’s own
battery should be used to power the system, but upon starting the
vehicle the power to the router should remain uninterrupted. Up to 30
seconds back-up without requiring an extra battery is thus a necessity.
Remote Management Requirements
A horror story for the PS broadband user is a box without remote
monitoring, configuration or setup possibilities. The demand is that
the connectivity to all routers, even to thousands of units, should
be monitored by a secure system from a secure location. The
communication between the management server and the router
should not depend on which links are used for the actual network
connection and should always be encrypted. Software upgrades
should be made easy in a way that even large amounts of routers can
be updated simultaneously. The routers in themselves should not have
fixed IP address requirements for security reasons. The contact to
management should always be initialised by the router. An intuitive,
easy to use management interface that can handle the number of
routers required and does not require any special coding expertise is
needed.
The status of the routers and their links, including connections, modems
and even their SIM-cards should be possible to monitor over large
amount of routers with a simple graphical interface.
Summary
Broadband connectivity is currently implemented in public safety
vehicles around the world. Some are implementing the connectivity
using currently available commercial technologies, while others use
dedicated networks or hybrid approaches. No matter what the approach
used, the high importance of the communication demands a multiple
network method. The costs of secure, high availability, wide coverage
area, fully dedicated networks are not economically feasible and will not
find funding.
Bespoke router equipment, specifically a multichannel router, is required
for the purpose. No general appliance based equipment, or hardware
originally developed for consumer use can meet the requirements for
secure, always online connectivity. The solution has special requirements
for software, hardware and remote management.
When all of these areas are considered in the design, the ultimate goal of
providing critical connectivity can be met cost efficiently.
As the users of the solutions put it:
“The multichannel routing system provides savings in time, resources,
money and lives”
The author is Juhani Lehtonen, VP of Sales at Goodmill Systems Ltd. He is advisor to the board of Goodmill Systems and is
responsible for the global sales in the organisation. Juhani has a long background in global sales and channel marketing with previous
companies including Tellabs Inc., Sphairon GmbH. He is also founder and chairman at a software and consultancy company GloCell Oy.
http://www.linkedin.com/in/juhanilehtonen