WHITE PAPER DIGITAL MOBILE RADIO IN THE 400MHZ BAND - www.titanict.com.au
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WHITE PAPER
DIGITAL MOBILE RADIO
IN THE 400MHZ BAND
www.titanict.com.auDIGITAL MOBILE RADIO IN THE 400MHZ BAND - COMPARING THE
BENEFITS, FEATURES AND FUNCTIONALITY OF DIGITAL MOBILE
RADIO SYSTEMS IN THE 400MHZ BAND
Regulatory changes in the 400MHz band Europe. TETRA was developed to meet the requirements
The Australian government regulatory body for radio of diverse kinds of end users (not only public safety
communications, ACMA, have undertaken a review of users). ETSI envisaged networks provided by national
their 400MHz band in 2010 to reduce congestion that organisations, with nationwide coverage, operating
currently exists in the band. The objective is to enable usually in urban environments. Consequently, TETRA is
the use of modern, spectrally efficient technology more like a cellular telephone system than other VMR
whilst prohibiting use of inefficient systems where standards and is suited to areas with high volumes of
appropriate. The following outcomes are currently being radio traffic. It relies on high user numbers to share the
implemented by ACMA in a transition plan: infrastructure cost.y
Land mobile radio mandated to 12.5kHz channel raster Why use digital radio?
with further splitting of channels to 6.25kHz permitted. Traditionally, for voice mobile radio (VMR) applications,
Prohibition of the use of 25kHz channels in high density conventional analogue systems have been used in the
(greater Brisbane, Sydney and Melbourne) and medium 400MHz band to cater for a wide range of industries.
density (greater Perth, Adelaide and Newcastle) areas In addition, data applications including those such as
with the exception of spectrally efficient multi-circuit telemetry, remote control and monitoring have been
systems (e.g. TETRA). implemented using analogue data radio technologies.
Digital mobile radio technologies serve as an
Harmonisation of government spectrum to promote alternative solution for converging voice and data
interoperability and efficient multi-agency networks applications in the 400MHz band. Digital mobile radio
within the 403¬430MHz band. can potentially be utilised for the following uses as a
single convergent system:
Alteration of the arrangement of the 450470MHz band to >> Voice communication including voice recording
allow 10MHz duplex frequency splits to enable the use
of cellular type technologies such as TETRA. >> Process control
>> GPS tracking for vehicles, terminals etc
These changes are a welcome introduction for highly Telemetry, remote control and monitoring
featured digital mobile radio technologies to be used
in the 400MHz band such as TETRA which, due to >> GPS based applications (e.g. incoming call
regulatory restrictions in the past, was not allowed to be >> Email and internet applications such as Wireless
licensed in Australia in this band. Application Protocol (WAP)
Introduction to TETRA and APC0-25 >> Automatic train operation
APCO Project 25 (APCO25) is a set of open standards initiated >> Database lookups including image downloads for
by APCO (Association of Public Safety Communications identification and maintenance purposes
Officials) and developed by the Telecommunications
Industry Association (TIA). One of the important aims in >> Private calling to handheld radios from SIP enabled
developing the standards was to ensure interoperability telephones (via a specialised gateway)
between public safety agencies, as proprietary systems had This white paper focuses on two digital voice mobile
prevented this in the past. The set of standards focuses on radio technologies that can provide these combined
voice priority, in particular for use in emergency scenarios. voice and data capabilities, TETRA and APCO Project 25
For this reason, the standard mandates that voice traffic (APCO25).
takes precedence over data traffic.
TETRA (TErrestrial TRunked RAdio) is a European
Telecommunications Standards Institute (ETSI)
standard. It has been established as the default
standard for public safety networks in the UK and in
Copyright 2019 // Titan ICT Pty Ltd. All rights reserved. 2TETRA APCO-25
Voice communication Individual, group, broadcast, emergency and Individual, group, broadcast, emergency and
priority calling priority calling
Process control TETRA enabled remote data modems available APCO‐25 is designed as a voice priority system.
supporting RS‐232, RS 485, Ethernet, Modbus Dedicated data channels (i.e. standalone base
etc serial interfaces station) required
GPS applications (e.g. vehicle Terminals support GPS interface and Application Terminals support GPS interface and Application
tracking & logging) Programming Interface (API) which enables Programming Interface (API) which enables GPS
GPS based applications based applications
Remote control and TETRA enabled remote data modems APCO‐25 is designed as a voice priority system.
monitoring, telemetry available supporting RS‐232, RS‐485, Ethernet, Dedicated data channels (i.e. standalone base
Modbus etc serial interfaces station) required
Automatic train operation One dedicated 25 kHz TETRA carrier can provide One dedicated 12.5 kHz APCO‐25 carrier can
approx. 9kbps raw data throughput for ATO provide approx. 4kbps raw data throughput for
applications. Can operate in full duplex to allow ATO applications. Simplex data only, inefficient
efficient use of automatic repeat requests (ARQ) compared to TETRA for transmission of ARQ data
for data integrity under RF fading repeat requests
E-mail/Internet (WAP) Many TETRA enabled PDA and terminals Limited APCO‐25 devices currently available which
available enabling WAP browsing applications support these applications
and e-mail capability
Image sharing (e.g. Many TETRA enabled PDA and terminals Limited APCO 25 devices currently available which
photographs for identification available enabling photographic image sharing support these applications
or diagnostic purposes) between TETRA devices
Database lookup (e.g. for re- Many TETRA enabled PDA and terminals Limited APCO‐25 devices currently available which
mote diagnostic access) available enabling information downloads to support these applications
devices from server databases
Voice recording/logging Devices can be integrated to TETRA network Devices can be integrated to APCO‐25 network to
to record and log transmissions and devices record and log transmissions and devices within
within the network the network
SIP telephone integration Gateway devices available which enable private Gateway devices available which enable private
voice calls between a SIP enabled telephone voice calls between a SIP enabled telephone and
and TETRA terminal APCO 25 terminal
Table 1: Comparison of applications and uses for TETRA and APCO-25 networks
CONVENTIONAL TRUNKED
Simple topology, networks consist of repeater sites consist of a For a given number of users, fewer discrete radio
base station unit, multicoupling and antennas. To form channel channels required compared to conventional. From
groups consisting of multiple sites, voting unit(s) are required another perspective, with a given number of radio channels, a
at each site or at a centralised location greater quantity of users can be accommodated.
Fast call set-up time. There is no delay incurred for channel Intelligence in the trunking controller makes it possible for any
assignment as in trunked networks available channel to be assigned to any user. For calls involv-
ing more than one site, the controller only includes those sites
which have participants in the call. If one traffic channel (base
station) fails, the capacity of the network only decreases by one
call slot; no users lose service
For smaller numbers of users it is cost effective as networks Greater impact on cost due to the requirements for additional
can consist of a single standalone base station trunking controllers at each site in addition to the network core
controller located at the master site.
Table 2 Considerations for Conventional and Trunked Networks
Copyright 2019 // Titan ICT Pty Ltd. All rights reserved. 3Considerations for implementation of The future release of APCO-25 Phase II will address
systems these issues where 2 channels will be supported per
TETRA and APCO-25 provide varying levels of operation 12.5 kHz of bandwidth.
and selection of any one of these technologies depends For the use of digital mobile radio to provide data
on end user requirements of the network including applications, it is possible for both TETRA and APCO-25
number of users, capacity, coverage area, applications to support combined voice and data. As TETRA supports
and uses (required capacity). full duplex, it uses this to its advantage for automatic
repeat requests (ARQ) to be communicated allowing for
higher efficiency in data throughput. Typical data rates
Scale of mobile radio network
for each standard are as follows:
The number of users accessing a mobile radio network
within the required coverage area can influence the →→ APCO-25 – 9.6kbps maximum throughput per 12.5
selection of an appropriate network topology and kHz carrier. Actual packet data rate following error
ultimately, the digital radio technology. correction and overheads of 4kbps
→→ TETRA – 7.2kbps maximum per channel (or timeslot)
Conventional radio is a system in which each group of totalling 28.8kbps maximum per 25 kHz carrier.
users is assigned one frequency. If one user is occupying Actual packet data rate following error correction
a channel, other users willing to make a call must queue and overheads of 3.5kbps per timeslot, or a total of
or wait until the channel is free. 9kbps when combining all four timeslots.
In contrast, a trunked radio system is where user groups Impact on site infrastructure
share an allocated group of frequencies. Trunking is a
Site infrastructure to support a digital mobile radio
system option for larger networks. Instead of allocating
network includes three basic elements being equipment
each channel to a set of users, trunking intelligence
accommodation, power source and antenna support
makes it possible for any available channel to be
structures. Radio repeater sites that are located in a
assigned to any user.
remote location may be in an area without access to
mains power and utilise solar power as the primary
The APCO-25 technology may be configured in either
power source. Utilising solar power creates an increased
conventional and/or trunked mode. TETRA may only
site infrastructure cost and it is important in any
be configured as a trunked network. The table below
design to minimise communications equipment power
compares the implementation considerations for
consumption to minimise the cost of implementing solar
conventional and trunked networks.
power systems. The following considerations should be
noted when implementing a digital radio system:
Refer to Table 2: Considerations for Conventional and
Trunked Networks on page 7. →→ Trunking based systems (whether they are APCO-
25 or TETRA) typically require site controllers to be
Equipment capacity co-located at each repeater site. Site controllers can
Dependent on the scale of the network and required data be power hungry devices dependent on the vendor
applications, TETRA and APCO-25 offer varying levels of or system type.
voice and data capacity per frequency carrier. →→ Typically base stations are rugged and operate
under extreme climate conditions. Site controllers in
A single TETRA transmitter utilising 25 kHz of spectral some trunking based systems are highly intolerant
bandwidth can offer 4 channels (or timeslots), where to these conditions and require active cooling to
one channel will be dedicated to control purposes overcome this. The use of air conditioning is highly
(subsequent transmitters at one site will support the wasteful on power generated at solar sites.
full 4 channels for voice and data). In comparison, an
→→ For APCO-25 trunked based systems, each channel
APCO-25 system requires 4 transmitters utilising 12.5
requires its own base station. Each channel that is
kHz of bandwidth each to achieve the same number of
added to a site will increase the power consumption
channels.
considerably. In contrast, each TETRA base station
supports 4 channels resulting in lower transmitter
TETRA utilises half of the required spectrum to achieve
power consumption when compared to 4 APCO-
an equivalent number of channels when compared to
25 base stations. Conventional APCO-25 systems
APCO-25. In addition, the use of four timeslots in a TETRA
typically consumes less average power in contrast
carrier enables the use of full duplex communication
to trunked APCO-25 as the base stations are only
(transmission in both directions) for voice and data
drawing maximum power when transmitting (e.g.
which is not supported with a single APCO-25 carrier.
when users are operating radios)
Copyright 2019 // Titan ICT Pty Ltd. All rights reserved. 4→→ Upgrade of network wide mobile fleet. The APCO-
Terminal devices 25 standard supports backwards compatibility with
Many data applications are device based and selection conventional analogue terminals whilst TETRA does
of terminals (i.e. mobiles and portable handhelds) may not. Utilising APCO-25 base infrastructure will allow
be based on its proposed uses. In addition to traditional gradual upgrade of analogue devices to APCO-25
mobile radio devices, TETRA enabled PDA’s are also devices.
available on the market. Both APCO¬25 and TETRA
→→ Upgrade of analogue base stations. For a multiple
devices support an Application Programming Interface
site network, legacy analogue base stations can
(API) which enables numerous feature rich data
be interconnected to an APCO-25 based network
applications to be enabled on its various devices. Some
via analogue gateways. This allows analogue base
of these advanced features include:
stations to be upgraded in a staged process.
→→ GPS based applications (e.g. incoming call location,
→→ The APCO-25 standard specifies dual mode
tracking & logging)
(analogue and digital mode operation) for both
→→ Email and WAP based internet browsing base stations and terminals. Upgrading the mobile
→→ Image sharing (e.g. photographs for person fleet to APCO-25 terminals allows interoperability
identification or equipment diagnostics) between conventional analogue and APCO-25 base
stations.
→→ Database query (e.g. for remote diagnostic access
to data) →→ Upgrading from an analogue radio network to
a TETRA based network. TETRA terminals are
Modern digital mobile radio networks also permit the not backwards compatible with legacy analogue
transmission data in process control, monitoring or networks. A defined planning strategy is required
telemetry applications. SCADA units are available which to upgrade both site infrastructure and the mobile
are TETRA capable and support a number of serial data fleet to TETRA.
interfaces including RS-232, Modbus etc or Ethernet →→ Antenna, feeder and multi-coupling upgrades.
interfaces. Typically, conventional analogue base stations are
licensed to run at 25 kHz. Upgrading to equivalent
Security of network APCO-25 base stations requires re-tuning or
Trunked networks provide a number of features which upgrade of multi-coupling systems to support 12.5
provide increased security to private mobile radio kHz channelling arrangements. TETRA systems
networks. Trunked networks store information of typically utilise receive diversity antennas and will
terminal units that are registered and/or make calls require upgrades to antenna installations at base
centrally on the network controller. Some of features sites.
this enables include: →→ Site DC power and accommodation capacity.
→→ Restrict access to the network to only terminals Individual site analysis is required to ensure
which are registered for use sufficient power source, battery backup, rack space
and/or floor space is available to accommodate
→→ Restrict individual terminals to certain features and
new base equipment.
functionality of the network
→→ Define the user groups which have individual access
Selecting the right Standard for your
→→ The dynamic and random allocation of channels
requirements
makes it more difficult for a casual eavesdropper to The common perception is that APCO-25 based systems are
monitor conversations most suitable for low and medium capacity deployments
→→ The identity of all users along with the time and which require large coverage areas while TETRA systems are
duration of messages are known to trace and/or suitable for small coverage area, high capacity applications.
These perceptions were due to characteristics of TETRA
ban abusers of the network
systems including base stations and terminals with low RF
→→ Supports end to end encryption of channels to power output and poor dynamic sensitivity of the TETRA
prevent eavesdropping receivers due to the modulation scheme (non constant
Migration from Analogue Networks envelope). In addition, the restrictions enforced by the ACMA
Careful planning is required when migrating from of frequency license allocations for TETRA in the 400MHz band
conventional analogue mobile radio networks to digital reinforced the preference for APCO-25 systems as they offer
mobile radio. Some critical issues that will impact the wider coverage being attractive for industries such as mining,
oil and gas, utilities and rail.
planned upgrade path include:
Copyright 2019 // Titan ICT Pty Ltd. All rights reserved. 5Latest developments in the TETRA marketplace driven →→ Improved modulation techniques to increase data
by demand and improvements in technology led to the throughput within an equivalent channel width.
introduction of compact TETRA systems with improved
receive sensitivity, higher power base station and terminals Current developments within the TETRA Release 2 include:
with similar characteristics to APCO-25 systems. In addition, a
→→ Increase of the current maximum coverage range of
recent change to the 400 MHz band plan by ACMA now enables
58km to 83km. Note that this is the theoretical maximum
the use of TETRA as an alternative to APCO-25 in the 400 MHz
and actual range is limited by RF losses and terrain.
band. The table below summarises some of the key features
and functionality of TETRA and APCO-25 for Phase I systems. →→ TETRA Enhanced Data Service (TEDS) is a new high speed
Refer to Table 3: Key features and functionality of TETRA and data service using different RF channel bandwidths and
APCO-25 systems below. data rates for flexible use of PMR frequency bands. TEDS
is fully compatible with TETRA Release 1 and allows for
Future development of TETRA and Project 25 standards ease of migration. TEDS will support adaptive selection of
Currently, both the APCO and TETRA organisational bodies are modulation schemes, RF channel bandwidths and coding
developing next generation standards named APCO-25 Phase according to propagation conditions and QoS negotiation
II and TETRA Release 2 respectively. for real-time class data applications.
The mandated developments and objectives for APCO-25
Phase II include:
→→ Increase of spectral efficiency utilising TDMA techniques
to provide two time slots within a 12.5 kHz RF channel.
This will enable equivalent spectral efficiency to TETRA
systems
→→ The control channel will support FDMA techniques to
enable backward compatibility with Phase I systems.
→→ An improved voice encoder (vocoder) shall be
implemented to further compress the required to 4800bps
per voice channel.
TETRA APCO-25
Trunked system, highly feature rich with more advanced Operates in both conventional and trunked modes. The
functionality. use of conventional networks is more cost effective for
a small number of users or small systems
Higher spectral efficiency. Half of the RF spectrum re- Developed primarily for public safety radio networks. As
quired to provide the same number of channels as a result emergency calls and voice calls take absolute
APCO-25 systems priority over data
Only one base station required to provide four channels. One base station required per channel. Higher overall
Savings on base station cost, power consumption and capital cost and power consumption compared to TETRA
rack space.
Typical coverage area of modern TETRA systems is 30- Typical base coverage area of APCO-25 systems is 40-
40km (rural). 50km (rural).
Cellular based standard. One carrier provides full duplex Full duplex capability for trunked APCO-25 systems, half
communications enabling higher data efficiency, duplex duplex for conventional systems
voice communication. Base stations allow call handover
between cells
Concurrent voice and data. As one carrier supports four Base stations support combined voice and data,
timeslots, two time slots can be used for data whilst one however, concurrent capability only in trunked APCO-25
is assigned for voice. Alternatively, all timeslots can be systems. Data throughput per base station or channel is
combined for up to 9kbps of data throughput approximately 4kbps
Table 3: Key features and functionality of TETRA and APCO-25 systems
Copyright 2019 // Titan ICT Pty Ltd. All rights reserved. 6How Titan ICT can add value Titan ICT has the expertise to advise and engineer the
most appropriate fit-for-purpose designs and systems
when implementing Mobile for mobile radio networks. Titan ICT can assist in the
Radio Systems following ways:
1 Facilitate business decisions regarding
Titan ICT has a long involvement in mobile radio implementation of services and mobile radio
networks for rail and mining industries throughout Perth technologies (e.g. an over arching strategy)
and country WA. Titan ICT has also been involved in
designing and implementing mobile radio networks for a 2 Develop standards and specifications for network
infrastructure and service delivery equipment to
number of ‘greenfield’ and ‘brownfield’ for some of WAs
ensure consistency across your business
biggest resource projects.
3 Engineering design for mobile radio networks and
Our experience includes: site infrastructure
Silcar Communications – Titan ICT designed 4 Tender package development and evaluation
the communications elements of the Public services
Transport Authority’s Southern Suburbs Rail
5 Project management of the implementation up to
Project including the private mobile radio (PMR) and including commissioning and final acceptance.
component.
Rio Tinto Simandou – Design of the Simandou P25 Involving Titan ICT in the early stages of planning for
PMR system for the 800km rail network connecting new or upgraded mobile radio networks will allow any
mine to port in West Africa project to benefit from this experience and expertise and
avoid pitfalls in design or implementation that might
Rio Tinto Iron Ore – Titan ICT designed the upgrade
cause significant project delays or lead to ‘band¬aid’
to Rio Tinto’s PMR system in the Pilbara. This
solutions.
project involved the design for 3 ports, 14 mines and
1300km rail. Titan ICT was also engaged to project
Choosing the right implementation strategy will ensure
manage the implementation and commissioning
the required services are delivered in a reliable manner
of the system which included radio upgrades,
at the lowest cost. Titan ICT’s experienced consultants
implementation of SINAD voters and the associated
will be happy to discuss how we might assist at any
consoles
stage of your mobile radio project.
WestNet Rail – Detailed Design and implementation
of the PMR system on the Midwest network from
Geraldton to Perenjori
Australia Premium Iron JV (API JV) – West Pilbara
Iron Ore Project (WPIOP) Phase 1 definitive
feasibility study (DFS) voice mobile radio network
review.
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Copyright 2019 // Titan ICT Pty Ltd. All rights reserved. V2
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