Ausgrid is investing more than $1 billion in the Sydney CBD electricity network over five years to 2014. Ausgrid's Sydney CityGrid project involves constructing new substations, replacing and upgrading high-voltage cables and constructing a new tunnel to link into our existing network of CBD cable tunnels. These tunnels connect to form an 8 km ring under Sydney's CBD that interconnects Ausgrid's substations. To provide a GRN P-25 coverage solution into these tunnels for Ausgrid's maintenance staff presented a challenge. Coverage is provided by utilising 'radio over fibre' repeater technology which rebroadcasts the NSW Government Radio Network from two dedicated base station sites located in two of Ausgrid's substations. Radiating cable, fixed to the ceiling of the tunnel, distributes the radio signals to the user in the tunnel, providing a method of communications deep underneath Sydney's CBD, where previously there was no way of communicating with the outside world. Steve Harvey, Engineering Manager, Distributed Coverage and Capacity Solutions (DCCS), CommScope

1. COMMS
CONNECT
2014
Ausgrid's
underground
high
voltage
cables
tunnels
Providing
P25
GRN
coverage
using
radio
over
fibre
repeaters
Speaker:
Steven
Harvey
COMMS
CONNECT
2014

2. CommsConnect
2013
Covering Ausgrid’s HV Cable Tunnels
City
South
City
West
City
East
–
Under
construcDon
•
Ausgrid’s
Sydney
CityGrid
project
to
construct
new
substaDons,
replace
and
upgrade
high
voltage
cables
and
construct
a
new
City
East
tunnel,
which
links
up
the
exisDng
cable
tunnels:
•
City
South
Tunnel
and
•
City
West
Tunnel.
•
These
three
tunnel
secDons
connect
to
form
a
`7km
ring
under
Sydney’s
CBD,
interconnecDng
Ausgrid’s
substaDons.
N

3. CommsConnect
2013
Challenges communicating underground
• OH&S
procedures
requires
that
tunnel
workers
have
a
method
to
contact
the
outside
world
if
the
need
arises,
whether
by
landline,
radio
or
mobile
phone.
Maintenance
staff
are
deployed
at
checkpoints
where
landline
phones
are
available,
then
use
simplex
radio
to
contact
the
working
team
further
within
the
tunnel.
• The
tunnel
maintenance
team
is
impacted
with
the
addiDonal
labour
required
to
man
these
checkpoints,
leaving
less
manpower
to
address
the
actual
maintenance
task
at
hand.
• Since
the
cable
tunnels
have
expanded
from
the
original
South
tunnel,
the
current
method
of
manning
checkpoints
puts
addiDonal
pressure
on
the
maintenance
team.
• A
radio
over
fibre
repeater
system
can
enable
coverage
into
these
tunnels
and
provide
a
beZer,
more
efficient
way
for
maintenance
staff
to
communicate
with
the
outside
world
using
the
exisDng
GRN
service.

4. CommsConnect
2013
Solution:
ION-M4 Radio over Fibre Repeater
• Ausgrid
are
a
GRN
user,
so
maintenance
staff
already
have
handheld
radios.
• A
dedicated
GRN
base-­‐staDon
uDlises
the
ION-­‐M
radio
over
fibre
repeater
system,
to
distribute
RF
signal
over
leaky
feeder
cable
run
throughout
the
tunnel.
• This
system
provides
a
method
of
communicaDon
to
colleagues
within
any
part
of
the
tunnel
and
above
ground
to
ensure
safe
and
stable
communicaDons.

5. CommsConnect
2013
ION-M4 Radio Over Fibre Repeater (RoF)
• Point
to
Point
ConfiguraDon.
Each
remote
unit
is
connected
to
one
opDcal
fibre.
One
single
fibre
supports
UL
and
DL
at
the
same
Dme.
• Network
Redundancy
is
achieved
by
two
independent
networks
interleaved.
A
single
system
will
meet
minimum
RSSI
target
Rx
levels.
A
B

6. CommsConnect
2013
ION-M Master Rack
•
System
B
Equipment
Room
•
ION-­‐M
RoF
Master
Rack
•
GRN
Base
StaDon
•
DC
RecDfier
and
BaZery
Back-­‐Up
•
Tx
Combining
(1+3
channels)

7. CommsConnect
2013
ION-M Master Rack – Block Diagram
Base
StaDon,
Tx
Combining
&
Rx
mulDcoupling
Single
Mode
OpDcal
Fibre
connects
master
rack
OTRX
To
Remote
Unit
Interface
cards
allow
RF
Levelling

8. CommsConnect
2013
Fibre – Connecting the Master Rack and Remotes
1310
1550
1310
1550
COUNTER-DIRECTIONAL
• The
Master
rack
and
each
of
the
remote
units
connect
to
each
other
via
using
single
mode
opDcal
fibre
(SMOF)
cable.
One
core
per
remote
• E2000-­‐APC
connectors
are
used
(8
degree
angled,
polished
connector)
• The
system
allows
for
a
maximum
of
10dB
opDcal
loss
(0.5dB
per
1000m
@1550nm)
and
Auto
levelling
ensures
RF
gain
remains
constant
no
maZer
what
the
opDcal
loss
is
(within
10dB)
• Wavelength
Division
MulDplexing
enables
signals
to
transmit
and
receive
at
the
same
Dme
over
a
single
fibre,
at
specific
opDcal
wavelength.
1310nm
is
used
for
the
downlink
(Tx)
and
1550nm
is
used
for
the
uplink
(Rx)

9. CommsConnect
2013
ION-M4 Remote Unit
• Passive Cooling
• 180W Power Consumption
• Common PA – *40dBm composite power shared
• Duplexer is 5MHz bandwidth, so frequency planning is required to
ensure channels are within the duplexer bandwidth
ION-­‐M
4
Remote
Fibre
Enclosure

10. CommsConnect
2013
ION-M4 Remote Unit

11. CommsConnect
2013
RF Design Parameter Considerations
• Link Budget: Downlink Power per carrier (control Channel) for
shared PA.
• The system is designed for a target received signal strength
(RSSI) of -95dBm (control channel) worst case for a single
system, to meet Delivered Audio Quality DAQ3.4
• Frequency Planning for duplexer bandwidth, and avoiding co-
channel and adjacent channel interference between System A
and B
• TDI – Time domain interference due to overlapping coverage
by simulcast signals. Maximum allowable delay is15
microseconds for P25 Phase 2 for signals of equal signal
strength. The difference in fibre lengths to neighbouring
remotes must be within 3000m before TDI occurs. Velocity
through fibre.
• BRx Uplink Noise figure for multiple Optical Remotes.
NF +10 log N, where N = number of remote units
• Uplink Gain Mode: ICP3 or Noise Figure Optimised.
Handset TX power and RU Receiver blocking
Downlink - RF Budget Frequency 450MHz
Power Output at MMR4 Remote 26.00 dBm for 8 x 25Khz carriers
Hybrid Combiner 3.50 dB
LDF4-50RN tails 0.15 dB 2
connector pairs 0.20 dB 3
Power into Radiax 22.15 dB
Radiax RXL5-1RN-B
attenuation at 450MHz is 3.1dB per 100m 0.031 dB/m
Coupling Loss (95% confidence) at 2m perpendicular distance from cable 86 dB
Handheld Receiver Noise Figure 10 dB
ENBW - Receivers Equivalent Noise Bandwidth 25000 Hz
Thermal Noise Threshold is KTB + NF -120.02 dBm
Minimum RSSI to Handset (Cf/N)
to meet DAQ3.4 is 20dB +/- 5dB above noise -95.02 dBm
Antenna Adj / Body Loss / Statistical Variation -9.00 dB
Design Target for RSSI -86.02 dBm
Min Power at end of Radiax -0.02 dBm
Max Length of Radiax (metres) 715.08 metres
from split output of Remote
Total distance covered by Remote 1430.15 metres
Total Length of Tunnels 7000.00 metres
Number of remotes 5.00
m

12. CommsConnect
2013
RF Design - Schematics
• Passive components such as couplers and splitters are used to distribute RF signals to
the leaky feeder and discrete antennas in sub stations.
• 50ohm terminations are used to isolate remotes connected by the same leaky feeder
cable.
• RF signals from System A are strongest where System B are weakest or vice versa

13. CommsConnect
2013
RF Design cont.
• Hybrid Couplers are used to mix
System A and B into antenna feeds for
Sub Station antennas
• Coupler values are selected to
distribute equal RF signals to each
discrete folded dipole antenna
Fibre
System
A
System
B

14. CommsConnect
2013
Leaky Feeder Cable RCT4-WBC-1X-RNA
• Mos.

15. CommsConnect
2013
Leaky Feeder – Coupling Loss
• Longitudinal
InserBon
Loss
(Pi)
Measure
of
loss
within
the
coaxial
cable
• Coupling
Loss
Measure
of
the
efficiency
to
radiate
the
signal
at
a
specified
distance
(D)
Y-Axis
X-Axis
D
Pin
Pout
LI = Pin - Pout
PR
Lc = Pin - [ PR(d) - Li • d ]

16. CommsConnect
2013
RCT Radiax – Radiating Mode (slotted)
Signal
Input
RF Signal is LAUNCHED from the Cable.
The signal “leaks” or couples out of the cable through
slots in the outer conductor.
“Radiating Mode” RADIAX®RCT Series

17. CommsConnect
2013
Types of tunnel – Leaky Feeder Cable Mounting
• Leaky feeder cable should be
spaced away from walls and
fixtures by 51mm.
• Refer to mechanical
specifications in data sheet
• Pre-cast concrete panel. CLIC
fasteners, spaced every 1m.
• Shotcrete lined tunnel, used
stainless steel catenary wire
suspended from cable tray,
fastened every 1m using cable
tie with plastic spacer to
separate RCT4 cable from wire.

18. CommsConnect
2013
System Commissioning – Master Rack
ION-­‐M
Master
Rack
Sojware
Alarms
can
be
interfaced
to
an
NMS
via
A.I.M.O.S
server
sojware

19. CommsConnect
2013
System Commissioning – RF Tests
Spectrum
Analyser
used
to
measure
control
channel
power
into
antenna,
to
be
verified
against
link
budget
calculaDons
All
coaxial
cables
tested
for:
Cable
loss
(inserDon
loss)
Return
Loss
(RL)
for
VSWR
Distance
to
Fault
(DTF)
to
verify
length

20. CommsConnect
2013
System Commissioning – RF Tests
Off
air
measurements
with
an
Anritsu
S412E
LMR
Master
(opDons
0521
and
0522)
for
P25
decode.
Control
Channel
RSSI
can
be
ploZed
and
presented
as
a
“snail
trail”
map
Outdoor
measurements?
Measurement:
RSSI
(dBm)
Excellent
>
=
-­‐70.0
dBm
Very
Good
>
=
-­‐80.0
dBm
Good
>
=
-­‐90.0
dBm
Fair
>
=
-­‐100.0
dBm
Poor
less
than
-­‐100.0
dBm

21. CommsConnect
2013
Fibre Testing and Commissioning
• Optical Power Meters – quick test, provides Optical loss.
• OTDR – Optical Time Domain Reflectometer.
Launch
Lead
1
Launch
Lead
2
Fusion
Splice
Connector

22. CommsConnect
2013
Summary and Benefits of Radio over Fibre Repeater
• CommScope
have
provided
a
GRN
P-­‐25
coverage
soluDon
into
these
tunnels
for
Ausgrid’s
maintenance
staff
using
CommScope’s
ION-­‐M
Radio
over
Fibre
repeater
which
re-­‐broadcasts
the
NSW
Government
Radio
Network
from
two
dedicated
Base
staDon
sites
located
in
two
of
Ausgrid’s
sub
staDons.
CommScope’s
RCT
radiaDng
cable,
fixed
to
the
ceiling
of
the
tunnel,
distributes
the
radio
signals
to
the
user
in
the
tunnel,
providing
a
method
of
communicaDons
deep
underneath
Sydney’s
CBD,
where
previously
there
was
no
way
of
communicaDng
with
the
outside
world.
• The
base
staDon/master
rack
has
been
expanded
to
feed
the
City
East
Cable
Tunnel,
reducing
expense
of
building
an
enDre
new
system
for
the
new
tunnel.
• A
similar
soluDon
using
a
dedicated
base
staDon
and
ION-­‐M
system
could
be
used
to
provide
Radio
Network
coverage
into
localised
underground
car
parks,
Shopping
Centres,
Road
and
Rail
tunnels.

23. CommsConnect
2013
How
can
we
help
you?
steven.harvey@commscope.com

24. www.COMMS-­‐CONNECT.com.au
Conference
materials
available
at
COMMS
CONNECT
2014