User Manual
ADCP-75-110 • Issue B • March 2001
Page 23
©
2001,
ADC
Telecommunications,
Inc.
Determine
the
Amount
of
Building
Attenuation:
If
a
donor
antenna
will
provide
the
RF
link
to
the
BTS,
determine
if
there
is
enough
signal
isolation
between
the
donor
antenna
and
the
in-
building
system
to
avoid
a
feedback
loop
and
signal
degradation.
This
step
can
often
be
accomplished
during
the
preliminary
walkthrough.
Discuss
Installation
with
Building
Management
and
Engineering:
Discuss
all
initially
anticipated
Digivance
ICS
coverage
areas
(including
any
obviously
desirable
cable
routings,
equipment
installations,
power
and
mechanical
requirements)
with
the
authorized
client
and
building
personnel
for
an
initial
approval/confirmation.
This
gives
a
good
estimate
of
the
extent
of
the
system
work
needed.
Occasionally,
some
of
the
system
design
work
can
be
accomplished
at
this
point.
2.10.2 Phase Two - System Design
Determine
forward
and
reverse
path
loss
and
then
design
for
unity
gain
on
the
uplink
and
maximum
power
out
of
the
DRU
on
the
downlink:
The
overall
purpose
of
the
Digivance
ICS
is
to
transparently
overcome
attenuation
losses,
not
to
provide
additional
gain
beyond
what
is
required
to
bring
the
signal
to
unity
gain.
Complete
the
following
steps
to
make
this
determination:
1. Determine
the
in-building
reverse
path
(uplink)
losses
at
typical
operating
frequencies
and
distances
from
the
subscriber
handset
(terminal)
to
the
DRU.
This
information
will
be
used
to
determine
the
optimal
uplink
signal
level
to
the
outside
world.
2. Determine
the
typical
composite
cell
site
Effective
Radiated
Power
(ERP)
into
the
system.
Calculate
the
interface
adjustment
required
to
feed
the
required
downlink
signal
level
to
the
DHU
in
order
to
drive
the
DRU
output
signal
at
the
desired
level.
Determine
the
location
of
the
DHU
and
its
RF
and
AC
power
sources:
Complete
the
following
steps
to
make
this
determination:
1. Determine
where
and
how
the
DHU
will
be
mounted.
2. Determine
the
location
of
the
DHU
AC
power
source.
3. Determine
the
RF
source
(LIU
with
BTS
or
RIU
with
BTS
through
donor
antenna)
for
the
DHU.
4. If
an
LIU
connection
with
the
BTS
is
required,
determine
the
distance
to
the
DHU.
5. If
a
RIU
connection
with
the
BTS
is
required,
determine
what
type
of
antenna
is
needed
and
where
it
can
be
mounted.
6. Determine
the
attenuation
or
amplification
requirements
for
the
DHU
to
BTS
interface.