MONZA, Italy — In 1929, state-owned Ente Italiano
per le Audizioni Radiofoniche, the Italian Body for Radio Broadcasting,
established its broadcasting control center in Sesto Calende, near Lake
Maggiore. The center monitored the frequency occupation on the entire spectrum
of medium wave and shortwave bands on a
World War II, EIAR became RAI, Radio Televisione Italiana and in the early
1950s, the rise of FM radio and TV broadcasting in Italy required the control
center to develop specific infrastructures to also monitor these frequencies.
technician carries out RF
at Rai Way’s
facilities around 1960.
In 1954 the control
center moved to Monza, within a Natural Park, and far enough away from any man-made
noise capable of affecting radio reception. In 2000, RAI spun off its former
broadcasting division and renamed it Rai Way, which presently operates as the
network provider for RAI.
control center in Monza is now the headquarters of Rai Way’s Innovazione,
Certificazione e Sperimentazione Radioelettrica (Radio Frequency Innovation,
Certification and Field Testing) department.
long run a comprehensive remote control and management system to operate its
transmitting sites, explains Aldo Scotti, head of ICSR at Rai Way. ”In the late
1990s, we envisioned the possibility of designing and operating a field
monitoring network for benchmarking purposes.”
monitoring network was not intended for everyday operational purposes. The idea
was to develop a network of monitoring stations within the service area of Rai
Way’s transmitters that was able to carry out statistical analysis on the
performance of Rai Way’s broadcast networks, along with that of competing
“We had the opportunity to start
from scratch, so we could really develop and tailor the best solution to comply
with the project’s goals,” Scotti said. “The monitoring network had to be
accurate, reliable, fully remote-controllable and budget-minded.”
monitoring network was named “Rete Leggera” (“Light Network”). A major
requirement for these monitoring stations was their capability to be positioned
almost anywhere, so they needed to be light and simple.
“This compelled us to move
the computational power elsewhere,” Scotti explained. The Rete Leggera design
features three physical layers: monitoring stations (detectors, Layer III),
network nodes (Layer II) and network management (Layer I).
Scotti is head of ICSR at Rai
monitoring station includes professional-grade receiving antennas and
combiners, one or more measurement device per each broadcast standard (MW, FM,
DAB+, DTT) and a local controller. Rai Way’s technicians custom-designed and
built the controller.
“Targeting 100 percent availability,
we carefully selected a specific IT-based fanless appliance where we installed
just two pieces of software — a basic OS and a proprietary package we created
to manage the operational cycle of the various receivers and communication to
the node level,” he said.
Depending on the
location of the monitoring station, the controller adjusts each receiver to
tune into a frequency from an assigned list, on a round-robin basis, then perform
the required measurements, according to a specific time window.
“We monitor the performance of our
networks, and also of our competitors, as well as checking for possible
interference from abroad [North Africa, the Balkins, etc.].” Each controller
stores the resulting data from the various measurements for five minutes, then
forwards a message including all the acquired data to its hierarchical network
node (Layer II), in a proprietary and “lite” format to limit the bandwidth
requirement and the amount of data transfer.
A specific message allows
each network node to acknowledge proper message reception. When the sending
controller receives confirmation, it deletes the measurement records. “We chose
to implement local controllers with virtually no local storage, to keep them
simple and to speed up each data transmission,” Scotti added.
from Rai Way’s “Rete
the Roma Monte Mario transmitting site in
Leggera controllers are connected to the network nodes (Layer II) via a
proprietary VPN. Each network node compares every measurement set with specific
thresholds, with the corresponding previous set and with the resulting mid-term
trend from the same monitoring station. The node subsequently deletes the data
situated within the relevant limits, while it stores each measurement records
not matching with the expected figures.
also build graphics for each monitored value at any measurement station. If
nothing “out-of-spec” is registered within 24 hours, each node stores one
measurement set per day from each monitoring station.
“The network nodes store data
corresponding to a specific moment when something went out of the expected
figure at a specific location,” said Scotti. “Rete Leggera is a sort of time
machine capable of reverting us to the very moment when something happened.”
On a daily basis, each
network node forwards the recorded events to the network management (Layer I)
of Rete Leggera. Network nodes generate alarms and triggers as the consequence of
a detected status change of the monitored parameters. The network management
aggregates all the data from the entire territory and maps each measurement
event to a specific transmitter and to a specific service.
broadcasts from a given transmitter are clearly receivable in one measurement
location, interference or other impairments can affect the quality of service
for the same broadcast at a different location.
Leggera’s advanced graphic interface provides mid- and high-level managers with
key performance indicators on the entire broadcasting network. Any kind of
drill-down is then allowed. Operators can compare the performance of a specific
Rai Way service versus the performance of a different service, either from Rai
Way or its competitors.
Rete Leggera can produce
historical reports for both nationwide or regional services, as well as for a
given transmitter. Transmitting sites with similar equipment but different
configuration can be compared from the point of view of their reliability and
overall availability. The same applies to nominally identical transmitting
sites that are using equipment from different manufacturers.
map of Italy showing status of Rai
“Rete Leggera monitoring stations. The image highlights two event
Rete Leggera network comprises 50 monitoring stations, covering about 70
percent of the potential nationwide audience. Rai Way intends to deploy 10
additional monitoring stations in the future.