Operation Manual

Fiber Distributed Antenna System (Fiber DAS)
101
Uplink
1. Set all values at default (factor setting may vary due to individual testing before shipping) for all bands
a. BIU: -10dB
b. FOI: -6, -6, -6
c. FOR: +12
d. Amp: +35 for low loss fiber, +45 for high loss fiber
2. Start with adjusting the high frequency band.
3. Turn RF on at the BIU. Ensure that only the RF strips being used ha
ve RF turned on.
4. Go to the FOR and turn the UL test tone on. Note the level being transmitted and the frequency. The level is
set at the factory to compensate for losses between the RU output port and the amplifier. Levels will vary unit
by unit.
5. Connect spectrum analyzer to the BIU BTS port and tune to the UL test tone frequency.
6. Measure the test tone level. Initial goal should be to set the UL t
est tone at the BIU BTS port to the same level
as being transmitted at the RU (zero dB system gain).
a. To reduce gain, it is recommended to adjust the attenuators in the BIU UL path. This will further
reduce UL noise.
b. To increase gain, it is recommended to adjust the gain in the RU UL path.
Note: Do not drive the FOR UL laser with more than 0dBm RF input. Recommended FOR UL input level
is approximately -5dBm.
c. The BIU UL input will be permanently damaged with signals stronger than +13dBm.
7. Record UL test tone level received in the spectrum analyzer. After all remote units on the sector have UL levels
set, the remotes will need to be balanced against each other (all are hitting the BTS UL at the same level).
Levels should be within about 1dB of each other.
Downlink
1. Set all values at default (factor setting may vary due to individual testing before shipping)
a. BIU: -15dB
b. FOI: -3, -3
c. FOR: +10
d. Amp: To be set based on actual input
2. Suggestion: Set FOR DL ALC level to one dB less than amp rating if unit alarms on DL.
a. A 43dB amplifier would have an ALC level set to +42.
3. Set BIU DL level to compensate for ICU interconnection loss. Do not exceed +10dB output of the BIU in the DL
path (will cause IM).
a. Suggest setting at maximum of +5dB output of the BUI.
b. Note there is 13 dB of inherent loss in the BIU. With 0dB settings in the BIU DL attenuators a 30dB
input signal will have an output of +17dB (30dB input minus 13dB inherent loss = 17dB). Adjust
attenuators so that BIU is approximately +5dB as a start.
c. Variations in the BTS input levels for loading must be taking into consideration. Full load and no load
power levels differ greatly. Do not allow the BTS to overdrive the BIU.
4. Adjust FOI attenuator levels in the DL path so that the RF input into the DL laser is approximately -5dB.
a. Note that the 0dB max into the laser is a composite level for all bands. By setting each band at -5dB
then total composite should not exceed 0dB.
b. Take into consideration that each BIU has two RF strips/paths. These must be taken into
consideration when setting the FOI levels.
c. Calculate full load conditions for all bands being fed into the FOI. Incorrectly setting the levels will
impact the system during times of most usage.
5. Set the desired gain in the remote.