RF linked simulcast radio network - radioactivity-tlc.it RF-linked simulcast network.… ·...
Transcript of RF linked simulcast radio network - radioactivity-tlc.it RF-linked simulcast network.… ·...
RF linked simulcast radio network
The best solution for wide area radio coverage
ABSTRACT
This presentation wish to explain the characteristic aspects of a simulcast radio
network. It will be considered only one broadcasting channel, RF linked, network,
but the same structure can be implemented for multichannel broadcasting.
Block diagrams of received signals up-link and transmited signals down-link
elaborations, togheter with an axplanation of the effects of amplitude, phase and delay
equalization, give a clear overview of network potential.
A simple propagation model simulation can help to correctly size network, which,
thanks to the “low” radio frequency band used, can cover a very wide geographical
area with a small number of repeaters. To further extend coverage area, a network
configuration including sub-master station will be explained.
Master, submaster and slave station appearance drawings and an example of a
network economic cost calculation will close this presentation.
Network – signal connections (1 ch)
Master
Fixed stationCH1
CH1
•The same RF channel over all Network => One communication per channel
•All stations directly connected to the network => Integrated communication sys
•Automatic roaming and hand-over => Easy to use
•Wide coverage area => easy to expand coverage by adding “slave” stations
•UHF narrow band interconnection channels => low infrastructure costs
•Functioning like single “big repeater” => automatic and simple conference call operation
Slave
Slave
Slave
Slave
Point-to –multipoint
link channels
CH1
Up-link signal path (example)
Radio Base Station MASTER
Receiver
160MHz
4W
Voter system
The real – time DSP voting selector chooses
the best signal (greater S/N) incoming from
the SLAVEs and sends it back to all the
SLAVE stations.
Control Center
160MHz
Receiver
450.000MHz
Receiver
450.025MHz
Transmitter
460.000MHz450.000MHz
Radio Base Station SLAVE
Transmitter
450.000MHz
DSP
Receiver
160.000MHz
Receiver
460.000MHz
Transmitter
164.600MHz
160.000MHz
450.025MHz
Slave
450.050MHz
SlaveReceiver
450.050MHz
Down-link signal path (example)
Radio Base Station MASTER
Receiver
160MHz
4W
Voter system
The DSP on the SLAVE stations perform
automatic carrier synchronisation, delay
compensation and audio equalization.
Control Center
164.600MHz
Receiver
450.000MHz
Receiver
450.025MHz
Transmitter
460.000MHz
460.000MHz
Radio Base Station SLAVE
Transmitter
450.000MHz
DSP
Receiver
160.000MHz
Receiver
460.000MHz
Transmitter
164.600MHz
164.600MHz
Slave
SlaveReceiver
450.050MHz
164.600MHz
What does “simulcast” mean?
All transmitters send the same information
signals on the same carrier frequency at
the same time
fc
fc
•The same RF channel over whole coverage area=> no channels change through
different repeaters, frequency saving
•Equivalent to a “big cell” single repeater => no special signalling like MPT1327 is
required (fully transparent to conventional mobile equipments).
•Automatic roaming and hand-over => Easy to use, fast set-up call
Network – down-link equalization
Transmitter
If the transmitted signals are
not accurately equalized in
amplitude, phase and delay
the mobile receiver will hear
a very noisy signal
9.492856
9.51896
Sj
400j1000
f c
.
0 5 10 15 20 25 30 35 4010
5
0
5
10
ms
Transmitter
delay to be compensatedon the station
TX1 (more delayed)
TX2
Transit delay
TX1TX 2
164.600MHz
Transmitter Receiver
460.000MHz
Network – down-link equalization
With the appropriate
equalization and
synchronisation the signals
“sounds” very good DSP
0 50 100 150 200 250 300
1
0.5
0
0.5
11.1
1.1−
si
3000 i
delay compensation
TX1 (more delayed)
TX2
Transmitter Transmitter
Transit delay
TX1TX 2
164.600MHz
Transmitter Receiver
460.000MHzDSP
10m 10m2m
Up to 20 Km Up to 20 Km
Up to 40 Km
Propagation model - 10m towers example
Antenna gain = 12dB
Base station antenna height = 10m
Mobile (train) antenna height = 2m
Frequency = 160MHz
RF Power = 10W / +40dBm
Horizon = 18.8 Km
5 10 15 20 25 30100
95
90
85
80
75
70
Km
dBm
p f0 i,( )
Horizon
ri
Coverage area / open channel
10 to 300 Km
(depending on heigth
of the antennas)
The coverage area depends on
the antenna’s height and on
the number of radio base
stations. It can spread from 10
to 300 Km or more.
The coverage area can be
easy adjusted to reach special
geometry (long valley, part of
lands, ... ).
The use of a single broadcast
channel permit an optimum
spectrum efficiency.
The coverage area may be
extended with the insertion of
other SLAVE / SUB-MASTER
base stationsThe communications are in “open channel”
(conference) mode over the entire coverage area .
This functionality ensures the best way to coordinate
emergency accidents (no “blinded trunking” ).
MASTER / SUB-MASTER / SLAVE
One Master station can receive
up to 8 Slave/Sub-Master
stations.
One Sub-Master station can
receive up to 8 Slave/Sub-Master
stations.
Master
Fixed stationCH1
CH1
Slave
Slave
Slave
Sub
Master
CH1
Slave
Slave
CH1
CH1
Base stations appearance
The base stations are very
compact and reuse the same
elementary units.
�
MUTE
SEL.
:
RADIO
LINE
POL DEVICE CHANNEL
:RX
UNLK 1
UNLK 2BUSY D
BUSY N
:
ON
PSM
Vout
Vin_OKVin_KO
:
TCS
PPSEEP
SYNC
DSP
RX
TXUNLK
MTCH
:
PWR RF HIGH
PWR RF LOW
PWR FAIL
ROS FAIL
TX
�
MUTE
- +
-SEL. +
:
RADIO
LINE
DEVICE CHANNEL
:
UNLK 1
UNLK 2BUSY D
BUSY N
:
UNLK 1
UNLK 2BUSY D
BUSY N
:
TCS
PPSEEP
SYNC
RX
TXUNLK
MTCH
: :
ON
Vout
Vin_OKVin_KO
:
TCS
PPSEEP
SYNC
RX
TXUNLK
MTCH
:
UNLK 1
UNLK 2BUSY D
BUSY N
:
PWR RF HIGH
PWR RF LOW
PWR FAIL
ROS FAIL
�
MUTE
- +
-SEL. +
:
RADIO
LINE
POL DEVICE CHANNEL
�
MUTE
- +
-SEL. +
:
RADIO
LINE
POL DEVICE CHANNEL
:
ON
PSM
Vout
Vin_OKVin_KO
:
TCS
PPSEEP
SYNC
DSP
RX
TXUNLK
MTCH
:RX
UNLK 1
UNLK 2BUSY D
BUSY N
:
PWR RF HIGH
PWR RF LOW
PWR FAIL
ROS FAIL
TX
:
PWR RF HIGH
PWR RF LOW
PWR FAIL
ROS FAIL
TX
:RX
UNLK 1
UNLK 2BUSY D
BUSY N
:
TCS
PPSEEP
SYNC
DSP
RX
TXUNLK
MTCH
:
ON
PSM
Vout
Vin_OKVin_KO
�
MUTE
- +
-SEL. +
:
RADIO
LINE
POL DEVICE CHANNEL
�
MUTE
- +
-SEL. +
:
RADIO
LINE
POL DEVICE CHANNEL
:
ON
PSM
Vout
Vin_OKVin_KO
:
TCS
PPSEEP
SYNC
DSP
RX
TXUNLK
MTCH
:RX
UNLK 1
UNLK 2BUSY D
BUSY N
:
PWR RF HIGH
PWR RF LOW
PWR FAIL
ROS FAIL
TX
:
PWR RF HIGH
PWR RF LOW
PWR FAIL
ROS FAIL
TX
:RX
UNLK 1
UNLK 2BUSY D
BUSY N
:
TCS
PPSEEP
SYNC
DSP
RX
TXUNLK
MTCH
:
ON
PSM
Vout
Vin_OKVin_KO
Sub
Master
Master
Slave
The Sub-Master station
integrate 3 full-duplex
transceivers
�
MUTE
- +
-SEL. +
:
RADIO
LINE
DEVICE CHANNEL
:
UNLK 1
UNLK 2BUSY D
BUSY N
:
UNLK 1
UNLK 2BUSY D
BUSY N
:
TCS
PPSEEP
SYNC
RX
TXUNLK
MTCH
: :
ON
Vout
Vin_OKVin_KO
:
TCS
PPSEEP
SYNC
RX
TXUNLK
MTCH
:
UNLK 1
UNLK 2BUSY D
BUSY N
:
PWR RF HIGH
PWR RF LOW
PWR FAIL
ROS FAIL