Digital Mobile Radio
Advanced base stations for the new generation of
professional mobile radio
Via Ponte Nuovo, 8 - 20128 Milano — Italy
Tel. +39.02.36514205 - FAX/Voicebox +39.1782242408
[email protected] - www.radioactivity-tlc.com
About Radio ActivityAbout Radio Activity Radio Activity S.r.l. is a young and dynamic
electronic engineering company with its
operational headquarters in Milan.
The company carries out design and pro-
duction of wired and wireless equipment
and systems for telecommunications net-
works in the professional market.
The engineering team to whom the Re-
search and Development is entrusted is
composed of engineers who have com-
pleted more than 20 years of experience in
this field at major telecommunications
companies.
The deep expertise in the design and im-
plementation of radio frequency hardware
and complete mastery of techniques for
programming DSP devices (Digital Signal
Processing), allow us to tackle complex
projects and offer customized solutions to
the real needs of the Customer.
The solutions identified are the result of
intense work by top-level professionals
with multidisciplinary skills, which skillfufly
integrate products and technology.
Radio Activity has advanced techniques,
for the establishment of analog and digital
simulcast radio networks and numerous
products for data transmission and cen-
tralization of communications via digital
audio matrices based on DSP.
In order to maintain the structure lean and
focused on its core business, all production
activities are entrusted to factories spe-
cializing in the assembly of electronic cir-
cuit boards and mechanical assembly.
Only strategic assets are maintained inside
with high quality levels. Besides of course
hardware and software design, we control
the choice of valuable components and
final testing of equipment and network.
This will guarantee the continuous updat-
ing of the used components and total
quality control of external processes.
DMR: an open ETSI standard DMR standard (ETSI TS 102 361/2/3) has been defined in ETSI envi-
ronment, by a working group composed by main PMR equipment
manufacturers worldwide.
Digital Mobile Radio is able to give “added value” to current analog
systems and at the same time it grants a gradual migration between
the two technologies, safeguarding investments and specific exist-
ing operational requirements.
DMR system can coexist with conventional analog systems on adja-
cent channels, without any performance loss of each of systems.
Frequency modulation has constant envelope (unlike the TETRA
which do not have a constant envelope).
Transmitters are very similar to their traditional analog version, be-
cause expensive linearization techniques are not needed: they can
work in saturation (clipping) mode (C class o superior) with very low
consumption => solar panels can be used.
The employed digital modulation is 4FSK (Four-level Frequency Shift
Audio/data channels are managed by two
timeslots sequences, working in TDMA
mode (Time Division Multiple Access), shar-
ing the same radio channel with 12,5KHz
bandwidth.
The two audio/data channel are per-
fectly separated and independent each
other, as if they were operating in a
conventional manner on different fre-
quency carriers.
Just one radio device (only 1
TX) provides 2 channels with-
out any RF coupling system
DMR overview
Key) and the information bits are transmitted in pairs, each pair
assigned to a frequency shift.
Transitions between a status and the following one (that is be-
tween a pair of bits and the following) are continue and
“smoothed” by a fil-
ter which reduces
high frequency com-
ponents.
The shape filter is a
“Raised Cosine” func-
tion.
DMR repeaters family by Radio Activity. Radio Activity has developed the DMR standard over the rugged
and largely utilized RA-XXX base stations. More then 1.400 RA-
XXX was installed in the past 2 years for emergency or essential
services applications.
The base station family RA-XXX has been designed using the lat-
est technologies in the Radio Frequencies and Digital Signal Proc-
essing fields. The transceivers are “fully digital ” developed fol-
lowing the theory of “soft radio” in which the modulation and
demodulation processes are performed by algorithms of Digital
Signal Processing (DSP) .
The radio modularity, as well as the other functions like remote
control, self test, self calibration, over temperature protection,
etc, minimizes the management and maintenance costs of the
equipment. The receiver section has excellent linearity character-
istics, which allow that more radio stations work on the same fre-
quency band.
These devices are fully programmable and easy to configure both
in Hw and SW, consequently this will provide optimum solutions
for any radio communication exigencies from a single repeater to
complex networks with tens of base stations.
Basic model already has all the characteristics to work as a dou-
ble standard repeater with all the features of analog and digital
Advantages of DMR Advantages of DMR
Over conventional systems
∞ Two contemporary communications
over 12.5KHz bandwidth
∞ European open standard
∞ Lower minister frequency license costs
per channel
∞ Increase spectral efficiency
∞ Fast and reliable data communications
∞ Smooth migration from analog systems
∞ Communication security with various
level of encryptions
∞ Powerful features (ID on PTT, emergency
call, text messages, ..)
∞ Built-in applications (positioning over
voice, telemetry, …)
∞ Easy upgradability from single repeater
to network
Over TETRA systems
∞ Very low infrastructure costs
∞ More coverage area
∞ Total reuse of existing conventional in-
frastructure (sites, power supply, ant…)
∞ Easy to manage and maintain
∞ Very low power consumption (solar
panel compatible)
∞ Low cost TCP/IP or UHF links between
the base stations
∞ Better spectral efficiency and same main
features
∞ Available in all PMR bands (70 MHz, 160
MHz, 450 MHz)
∞ Availability of simulcast solutions for low
traffic and wide area coverage systems
DMR overview
service. It can be equipped with double receiver to counteract fad-
ing effects through diversity space reception.
DMR: network solutions The Radio Activity base stations are ready to make networks ex-
pandable from single repeater to a multi-frequency or iso-
frequency multi-site system, with a lot of type of links, operating
with the most common transportation system technologies, like
microwave link, DMR UHF radio, fibre optics, copper pairs, generic
TCP/IP connections and mixed media also.
The entire radio system is designed to automatically react to fail-
ure situations and seek the configuration of minimum possible dis-
ruption (progressive degradation). The network reacts, depending
on events, re-directing the paths of the signals on the transport
network, creating sub-autonomous networks, up to turns an iso-
lated base station as a simple repeater (local bridge) up to reduce
power consumption in the over temperature events.
The precision in timing and synchronization, the high performance
digital equalization and the built-in algorithms guarantee an opti-
mal functionality even in equal field strength areas.
DMR simulcast environmental
has many advantages respect
to the analog one due to the
better C/I performance and
due to the powerful coding
applied. The result is a clear,
noise free, mobile radio net-
work in critical propagation
area also.
About SIMULCAST About SIMULCAST
A simulcast network is a very powerful
radio network in which all the repeaters
are active on the same frequency and at
the same time.
Main advantages:
∞ Automatic and continuous roaming
and hand-over => Easy to use, fast
setup call
∞ Functioning like single “big repeater”
=> automatic and simple conference
call operation
∞ All stations directly connected to the
network => Integrated communication
sys
∞ The same RF channel over all Network
=> no change of channel in the cover-
age area, frequency saving
The simulcast solution is the best in case of
emergency due to easy and fast “open
channel” mode of operation:
∞ all people involved in emergency can
listen all communications so they are
continuously informed about the criti-
cal situations
∞ the regulation of network access is
made by user, absolutely more intelli-
gent and efficient than a trunking SW
logic
All transmitters send the same information signalson the same carrier frequency
fc
fc
fc
The two received signals can be com-
bined by digital ri-phasing to obtain
the vectorial sum.
No scanning required.No scanning required.No scanning required.
Forget your previous Forget your previous Forget your previous
trouble experience on trouble experience on trouble experience on
simulcast networks.simulcast networks.simulcast networks.
DMR overview
Unique or more interesting Radio Activity features ∞ Automatic dual mode DMR/Analog operating
∞ Designed for TCP-IP simulcast applications
∞ Soft diversity receiver
∞ Full LINUX core
∞ Automatic alarm’s messages sending by the base station to
the mobile equipments
∞ Ethernet port with full traffic available (DMR audio, data
and signaling) for Operative Center applications or tele-
phone gateway
∞ Extra low ETH bandwidth (33.6kb/s) required to connect
the base stations
∞ Software remote upgradability
∞ Easy scalability from single repeater to simulcast network
∞ Built-in both digital and analog voting systems
∞ A lot of timing/synchronism mode available for simulcast
applications
∞ Powerful GSM/GPRS/TCP-IP/DMR based remote control
∞ Factory remote assistance available
∞ Multi-key encryption
∞ Very low power consumption (typ. 8 W @RX)
∞ Compact modular design
∞ 100% TX duty cycle
∞ No fans needed
Main realizationsMain realizations
∞ A “dual mode” simulcast network TCP-IP
linked in 80MHz band with 16 base sta-
tions. User: Italian motorway.
∞ 300 radio stations in 450MHz band for
fast data transmission point-to-
multipoint. User: ALBACOM.
∞ 700 radio stations in 450MHz
band for point-to-point com-
munication. User: WIND/ENEL.
∞ supply of more than 150 systems based
on IP modem RA-md1 for use with “over
the mains” communication
systems. User: ENEL Dis-
tribuzione.
∞ radio stations for point-to-
point connection. User: EDISON.
∞ simulcast radio network for emergency
radio coverage for Fire Brigades in
Lötschberg rail tunnel between Frutigen
and Raron (Switzerland): 34 km of tun-
nels with 26 simulcast radio stations
linked by multiplex.
∞ four simulcast VHF radio networks with
UHF links , Master and Sub-master base
stations, for Region Liguria.
∞ simulcast VHF radio network with mixed
connection via multiplex and “over the
mains” carrier with delays self-
calibration through the GPS signal. User:
Valais Electric Body (Switzerland).
∞ emergency radio coverage of motorway
tunnel in Amberg for ASCOM Austria.
∞ three channel emergency simulcast ra-
dio network with optical links for radio
coverage of motorway tunnel in Liguria.
∞ several simulcast radio networks with
UHF links and microwave link for data
and audio mobile communications
( Mountain Region of Campania, Alpine
Rescue in Marche Region , Aqueduct of
Romagna, Motorway and Police of Val
d'Aosta Region, Watch services of FIAT,
Commonwealth of Engelberg, ..… )
UHF links
UHF links
Slave
Slave
Master
Sub-Master
p.p.
s.
SLAVE
IP
p.p.
s.
DMR overview