International Journal of Engineering, Applied and Management Sciences Paradigms, Vol. 24, Issue 01
Publishing Month: May 2015
An Indexed and Referred Journal
ISSN (Online): 2320-6608
www.ijeam.com
Professional Mobile Radio Technology Overview:
Tetra Vs DMR
Reem Ahmed Hassan Elsheikh¹ and Dr. Amin Babiker A/Nabi Mustafa²
¹Faculty of Engineering, Department of Communications, Al-Neelain University, Khartoum, Sudan
[email protected]
²Faculty of Engineering, Department of Communications, Al-Neelain University, Dean of Faculty, Khartoum, Sudan
[email protected]
TETRA is a “revolution” instead the DMR is an
“evolution” of the existing analog two-way radio. TETRA
is a trunking system targeted to point to point
communications in multi cell and high traffic density
environments. Like a telephone network, hundreds of users
in a little area require a lot of radio cells to deliver the
communications. DMR is a dedicated channel or trunking
system targeted to provide large coverage rather than
capacity. At the end, TETRA may give some advantages
over DMR especially for medium to high capacity
networks such as big town or large campus. [3]
Abstract
Private/Professional Mobile Radio (PMR) refers to the
two-way radio communication system that allows users
sharing the same range of frequency to communicate with
the others. PMR can be classified into two main systems
which are conventional and trunked radio systems. In
conventional system, a frequency band is permanently
dedicated to a voice channel. However, using trunked
radio system can increase the spectrum efficiency by
having pool of frequencies which are temporarily assigned
to a group of users called talk group only when required.
In trunked radio system, digital trunked radio offers better
functions and features than analog trunked radio such as
voice quality, security, spectrum efficiency and cost. There
are many digital trunked radio technologies lunched in the
market. However, in this paper, only Terrestrial Trunked
Radio (TETRA), and Digital Mobile Radio (DMR) are
discussed and compared since they are developed and
standardized by international standards organizations.
Moreover, these technologies are chosen by many
operators and deployed in many regions across the world.
Keywords: Private Mobile Radio, Terrestrial Trunked
Radio, Digital Mobile Radio, Time Division Multiple
Access
I.
II.
PMR:
Private Mobile Radio (PMR) refers to radio trunking
services
that
provide
two-way
mobile
radio
communications for mobile users to connect to PMR voice
telephony and data networks.
PMR offers a two-way communications service that
permits users to talk over a short distance on a simple local
system or wide-area, even nation-wide on a more complex
system.
2.1 What determines the range of the radio?
Introduction:
The power of the radio is one of the main factors in
determining range. Hand-portable radios are limited to 5
Watts ERP (radiated power from the aerial), whereas the
power allowed from some mobile (vehicle-mounted)
radios is 25 Watts ERP. Height is another important factor.
Under ideal conditions, a PMR radio signal may be
received up to 3km away; a professional hand-held up to
5km; and a vehicle-mounted up to several tens of
kilometres. With the addition of a repeater system, the
coverage can be extended to an entire country. [1]
Private Mobile Radio (PMR) - sometimes called
Professional Mobile Radio - was developed for business
users who need to keep in contact over short distances with
a central base station; a typical example is a taxi company.
PMR is also widely used by emergency
desktop
controllers with direct access to the radio network. [1]
The paper examines the features and functionality of Tetra
and DMR, as they exist in the drafted standards. TETRA is
well supported standard that is well suited to the needs of
the emergency services and other ‘mission critical’
purposes, as well as professional users. DMR, on the other
hand, is still developing, and provide a solution for the
consumer and commercial user starting from the lower end
of the scale.[2]
2.2 Frequency: VHF or UHF?
Typically PMR users are licensed for VHF (Very High
Frequency, normally 133MHz-170MHz) or UHF (Ultra
High Frequency, normally 430MHz-470MHz). The lower
the frequency, the greater the range of transmission. This
IJEAM
www.ijeam.com
66
International Journal of Engineering, Applied and Management Sciences Paradigms, Vol. 24, Issue 01
Publishing Month: May 2015
An Indexed and Referred Journal
ISSN (Online): 2320-6608
www.ijeam.com
does not mean that VHF is automatically the best choice,
because VHF signals do not penetrate buildings as well as
UHF, which is therefore more suited to urban areas. [1]

2.3 What are the benefits of having a Private
Mobile Radio (PMR) licence? [5]

III.
Having a licence to use these bands offers significant
benefits for radio scheme:
•
•
•
Methodology:
This paper shows a comparative study for the most
competitive PMR technologies, TETRA, and DMR in term
of standards, characteristics, coverage areas, downlink &
uplink, development, terminal choices, SWOT analysis,
functionality, Spectrum efficiency and data Throughput.
Gives
the
ability
to
encrypt
radio
communications.
There is no interference from other users.
The licence will give increased power; better
range and penetration.
IV.
2.4 Private mobile radio / business radio
technologies: [4]






TETRA: [4]
TETRA is a modern standard for digital Private Mobile
Radio (PMR) and Public Access Mobile Radio (PAMR). It
offers many advantages including flexibility, security, and
ease of use and offers fast call set-up times. This makes it
an ideal choice for many business radio communications
requirements.
There are many different business radios or private mobile
radio technologies that are currently in use around the
globe. These different business radio or private mobile
radio technologies vary from analogue to digital and also
vary in complexity according to the requirements. Some of
the main technologies are listed below:

P25: P25, Project 25 or APCO-25 is a
standardised digital radio communications system
that is generally used by federal, state/province
and local public safety agencies.
ARIB DCR: This digital private mobile radio
standard originated within Japan.
The name TETRA stands for TErrestrial Trunked RAdio.
It is aimed at a variety of mobile radio communications
users including the police, ambulance and fire services; it
is applicable for utilities, public access, fleet management,
transport services, and many other users.
Analogue Private Mobile Radio, PMR:
Analogue radio systems are not normally
specified in the same way as digital ones require
to be. Typically the use FM and have 25 kHz
bandwidth requirements.
Trunked Private Mobile Radio: Trunking is a
system whereby PMR systems are able to operate
over a wide area. Signals are picked up from the
remote station and "trunked to the local station.
MPT 1327: MPT 1327 is the most widely used
standard for analogue trunked radio. Originally
developed in the UK by the then Ministry of Posts
and Telecommunications (MPT) it has been
widely adopted across the globe.
TETRA: This was one of the first digital
standards to be launched. Originally the letters
stood for Trans European Trunked RAdio, but as
the system is now being used beyond Europe the
abbreviation now stands for TErrestrial Trunked
Radio. TETRA is widely deployed, especially for
the emergency services.
DMR: Digital Mobile Radio, DMR is one of the
growing digital PMR systems
dPMR: This digital Private Mobile Radio. It is a
different specification to that of the DMR and
utilises different techniques and is therefore not
compatible.
NXDN : This standard originated within the
USA but it is also available in Europe and other
countries.
4.1 TETRA radio beginnings:
Work started on the development of the TETRA standards
in 1990 and has relied on the support of the European
Commission and the ETSI members. The first standards
for the new private mobile radio communications system
were ready in 1995 to enable manufacturers to design their
radio communications equipment to interoperate
successfully.
4.2 TETRA radio features:
TETRA radio offers many new and valuable features.
These include a fast call set-up time, group communication
support, direct mode operation between individual radios,
packet data and circuit data transfer services, better
economy of frequency spectrum use than the previous
PMR radio systems and in addition to this it provides
advanced security features. The system also supports a
number of other features including call hold, call barring,
call diversion, and ambience listening. There are two
releases of the TETRA radio standard.

TETRA Release 1: TETRA Voice plus Data
(V+D) standard.
IJEAM
www.ijeam.com
67

International Journal of Engineering, Applied and Management Sciences Paradigms, Vol. 24, Issue 01
Publishing Month: May 2015
An Indexed and Referred Journal
ISSN (Online): 2320-6608
www.ijeam.com

TETRA Release 2: This release of the TETRA
radio standard introduced a number of new
features into the TETRA radio standard:
o
TETRA Enhanced Data Service (TEDS).
o
Mixed Excitation Liner Predictive, enhanced
(MELPe) Voice Codec.
o
Adaptive Multiple Rate (AMR) Voice
Codec.
o
Trunked Mode Operation (TMO) Range
Extension.
TETRA Release 2 standard provide additional
enhancements as:
• Range extended up to 83 km.
• More compressed codec.
• Many choices of modulation and RF bandwidth.
• Data transmission up to 500 kbits/s on 150 KHz
bandwidth.
V.
DMR Tier I: Unlicensed
• DMR Tier I products are for licence-free
use in the 446MHz band.
• Tier I provides for consumer applications
and low-power commercial applications,
using a maximum of 0.5Watt RF power with
an integral antenna and working in directmode. With a limited number of channels
and no use of repeaters, no use of telephone
interconnects, and fixed/integrated antennas,
Tier I DMR devices are best suited for
personal use, recreation, small retail and
other settings that do not require wide area
coverage or advanced features.
 DMR Tier II: Conventional DMR
Tier II covers licensed conventional radio
systems, mobiles and hand portables
operating in PMR frequency bands from 66960MHz working in direct mode or using a
Base Station (BS) for repeating. The ETSI
DMR Tier II standard is targeted at
professional users who need spectral
efficiency, advanced voice features and
integrated IP data services in licensed bands
for high-power communications. ETSI DMR
Tier II specifies two-slot TDMA in 12.5 kHz
channels.
DMR: [9]
DMR standard was established in 2005 and has many
benefits in comparison to legacy analogue systems and to
other digital approaches. The designers of DMR looked at
the market requirements and opted to use TDMA as the
underlying technology for the standard as it delivers some
very clear benefits such as:
• Predictable doubling of capacity in existing 12.5 kHz
licensed channels.
• Backwards spectrum compatibility with legacy analogue
systems.
• Efficient use of infrastructure equipment.
• Longer battery life and greater power efficiency.
• Ease of use and creation of data applications.
• System flexibility through simultaneous voice and data
calls.
• Advanced control features.
• Superior audio performance compared to analogue.
DMR Tier III: Trunked
• DMR Tier III covers trunking operation in
frequency
bands
66-960MHz
for
professional users.
• The Tier III standard specifies two-slot
TDMA in 12.5 kHz channels. Tier III
supports voice and short messaging handling
with built-in 128 character status messaging
and short messaging with up to 288 bits of
data in a variety of formats. It also supports
packet data service in a variety of formats,
including support for IPv4 and IPv6.
5.1 The DMR Standard:
1.
2.
VI.
ETSI DMR standard.
Three tiers in the DMR standard:
Results and Discussion:
6.1 Downlink Vs Uplink: [7]
Technology
Path
DMR
TETRA
Downlink (base station)
DMR
TETRA
Uplink (portable)
IJEAM
www.ijeam.com
68
International Journal of Engineering, Applied and Management Sciences Paradigms, Vol. 24, Issue 01
Publishing Month: May 2015
An Indexed and Referred Journal
ISSN (Online): 2320-6608
www.ijeam.com
Power output
44.0dBm ERP
44.0dBm ERP
36.0dBm ERP
31.8dBm ERP
Equivalent noise bandwidth
8kHz
18kHz
8kHz
18kHz
Dynamic Co-channel SINR for
DAQ 3.4
15dB
16dB
15dB
16dB
Radio terminal receiver noise
figure
8dB
8dB
8dB
8dB
Radio terminal receiver
sensitivity (including diversity)
-112dBm
-107.7dBm
-112dBm
-109.4dBm
4.3dB
Difference
6.8dB
Table (1)
6.2 The history of standards development: [6]
6.3 Significant overlap between TETRA and DMR
in the lower to mid professional tiers: [9]
Figure (1)
Figure (2)
6.4 Tetra Vs DMR: Characteristics:Standard
DMR
Tier II
Yes, ETSI
Business
Targeted¹
C
DMR
Tier III
Yes, ETSI
B, C
Network Size
C or T²
Modulation
Local,
Regional
C
4FSK
Local,
Regional
T
4FSK
TDMA/
FDMA
TDMA
2 Slots
TDMA
2 Slots
Vendor System Name³
Motorolla: Mototrbo,
Selex
ECOS, Radio Activity
Tait: TaitNet
IJEAM
www.ijeam.com
69
International Journal of Engineering, Applied and Management Sciences Paradigms, Vol. 24, Issue 01
Publishing Month: May 2015
An Indexed and Referred Journal
ISSN (Online): 2320-6608
www.ijeam.com
Tetra
Yes, ETSI
A, B
Nationwide
T
π/4-QDPSK
TDMA
4 slots
Motorolla, EADS,
Teltronic, Rohill, Rhode
& Schwarz
Table (2)
1.
2.
3.
A = Public Safety or Mission-Critical, B = Critical Infrastructure, C = Professional or Business and Industrial
C = Conventional, T = Trunking
Examples only
6.5 Tetra Vs DMR: SWOT Analysis:- [8]
Strength
Weakness
Opportunities
TETRA
Open
standard
DMR
Open standard
TETRA
Difficult to fit in
bands with
12.5khz spacing
DMR
Lack of features
for critical
communications
TETRA
Excellent
support of
applications
Supported
by industry
Compatibility
with analogue
radio
No compatibility
with analogue
radio
Vendor lock-in
issues due to
proprietary
deviation
Easy to
deploy
solutions
Full duplex
individual &
telephone
calls
Higher data
throughput
support of
VHF
frequency
Currently no
support of VHF
No support of
full duplex calls
High
reliability/a
vailability
No support op
simulcast
transmission
Lower data
throughput
Terminal
support
specialized
application
DMR
Low cost
solutions
for rural
coverage
Simplicity
of
deploying
Threats
TETRA
Complexity
of solutions
DMR
Competition
from PMR
over cellular
Competitive
DMR
packaging of
systems and
terminals
Solutions are
not designed
for high
availability
Table (3)
VII. Conclusion
References:
[1] http://www.mobilemarinesystems.com/
TETRA and DMR are the digital trunked radio
technologies standardized by the international standards
bodies. All of them utilize the TDMA technique to
increase the spectrum efficiency that is four times
higher than analog system. In addition, TETRA can
achieve the higher data rate compared to the other
technologies; hence, it is suitable for users who require
data transmission in addition to voice communication.
DMR operate on 12.5-kHz channel, while TETRA
operates on traditional 25-kHz channel which is more
suitable for country without narrowband plan in terms
of spectrum management. However, TETRA can
deploy more number of cells. In DMR, there is
limitation in number of cells. Hence it is not suitable for
nationwide implementation.
[2] www.analysysmason.com/
[3] http://www.ronet.co.za/
[4] http://www.radio-electronics.com/
[5] http://www.etsi.org/
[6] http://blog.taitradio.com/
[7] http://www.tandcca.com/
[8] http://digitalradiotoday.com/
[9] http://www.dmrassociation.org/
IJEAM
www.ijeam.com
70