User's Manual Part 1

Designing a Fusion Wideband Solution
Page 90 InterReach Fusion Wideband Installation, Operation, and Reference Manual
© 2013 TE Connectivity Ltd D-620616-0-20 Rev H • TECP-77-044 Issue 7 • May 2013
Table76. LinkBudgetConsiderationsforNarrowbandSystems
Consideration Description
BTS Transmit Power The power per carrier transmitted from
the base station output
Attenuation between
BTS and Fusion 
Wideband
This includes all losses: cable,
attenuator, splitter/combiner, and so forth.
On the downlink, attenuation must be chosen so that the
maximum power per carrier going into the Main
Hub does not exceed the levels given in “Maximum Output Power per Carrier” on page 65.
On the uplink, attenuation is chosen to keep the maximum up
link signal and noise level low enough to
prevent base station alarms but small enough not to cause degradation in the system sensitivity.
If the Fusion Wideband noise figure minus
the attenuation is at least 10 dB higher than the BTS noise
figure, the system noise figure is approximately that of Fusion Wideband alone. Refer to “Connecting a
Main Hub to a Base Station” on page 101 for ways to independently set the uplink and downlink
attenuations between the base station and Fusion Wideband.
Antenna Gain The radiated output power includes antenna gain. For example, if you use a 3 dBi antenna at the RAU that
is transmitting 0 dBm per carrier, the effective radiated power (rela
tive to an isotropic radiator) is 3 dBm
per carrier.
BTS Noise Figure This is the effective noise floor of the base station input (usually base station sensitivity is this effective
noise floor plus a certain C/I ratio).
Fusion Wideband Noise
Figure
This is Fusion Wideband’s uplink noise figure, which varies depending on th
e number of Expansion Hubs
and RAUs, and the frequency band. Fusion Wideband’s uplink noise figure is specified for a 1-1-8
configuration. Thus, the noise figure for a Fusion Wideband system (or multiple systems whose uplink
ports are power combined) is NF(1-1-8) + 10*log(# of Expansion Hubs). This represents an upper-bound
because the noise figure is lower if any of the Expansion Hub’s RAU ports are not used.
Thermal Noise This is the noise level in the signal bandwidth (BW).
Thermal noise power = –174 dBm/Hz + 10Lo
g(BW).
Required C/I ratio For each wireless standard, a certain C/I (carrier to interference) ratio is needed to obtain acceptable
demodulation performance. For narrowband systems, (TDMA, GSM, EDGE, iDEN, AMPS) this level
varies from about 9 dB to 20 dB.
Mobile Transmit Power The maximum power the mobile can transmit (power tra
nsmitted at highest power level setting).
Multipath Fade 
Margin
This margin allows for a certain level of fading due to m
ultipath interference. Inside buildings there is
often one or more fairly strong signals and many weaker signals arriving from reflections and diffraction.
Signals arriving from multiple paths add constructively or destructively. This margin accounts for the
possibility of destructive multipath interference. In RF site surveys the effects of multipath fading are
typically not accounted for because such fading is averaged out over power level samples taken over
many locations.
Log-normal Fade 
Margin
This margin adds an allowance for RF shadowing
due to objects obstructing the direct path between the
mobile equipment and the RAU. In RF site surveys, the effects of shadowing are partially accounted for
since it is characterized by relatively slow changes in power level.
Body Loss This accounts for RF attenuation
caused by the user’s head and body.
Minimum Received
Signal Level
This is also referred to as the “design
goal”. The link budget says that you can achieve adequate coverage
if the signal level is, on average, above this level over 95% of the area covered, for example.
Protocol Signal
Bandwidth
Thermal Noise
TDMA 30 kHz –129 dBm
GSM 200 kHz –121 dBm
iDEN 25 kHz –130 dBm