eNB with external power amplifier

Adding an external power amplifier, will not be reflected automatically on power advertised in the SIB2 in the referenceSignalPower information element. referenceSignalPower is used by the UEs to adjust their transmission power so that the received signal is at the correct level on the eNB side.

If you use a version 2023-09-08 or later, set the tx_power_offset parameter in the rf_port configuration object to the external power amplifier gain. Otherwise follow the procedure described below:

To calibrate the referenceSignalPower value:

1) figure out the referenceSignalPower computed by eNB automatically (based on gain setting) without amplifier:

let the system run without any power amplifier and note the value broadcasted by the eNB "referenceSignalPower" in the SIB2.

pdsch-ConfigCommon { referenceSignalPower 7, p-b 1 },

2) calibrate referenceSignalPower based on:

amplifier gain
referenceSignalPower computed on step 1

To do that:

stop the system, modify the enb.cfg to enable manual setting of the ref power in the cell

cell_default : { [...] manual_ref_signal_power : true }

3) set the correct value in sib2.asn : "referenceSignalPower computed on step 1" + "amplifier gain"

Note: that once manual_ref_power_signal is set to TRUE, any change to the cell gain or RF gain all the procedure should be reevaluated.