eNB/gNB with external LNA

Using an external LNA has different impacts on:

1) received signal level. It may cause saturation of received signal. To avoid that:

connect a UE (very close to eNB) and start uplink transfert.
adjust rx_gain based on "t spl" output:

(enb) t spl Press [return] to stop the trace --TX 1----- dBFS --RX 1----- RMS MAX SAT RMS MAX -23.1 -4.5 0 -47.4 -35.9 -23.1 -5.4 0 -47.4 -35.6 -23.1 -5.5 0 -47.4 -35.9

ideally, RMS should be around -15 and MAX should be around -3, when the UE is transmitting.

2) EPRE measured by eNB/gNB. UL EPRE measurements are used for logging, for pathloss estimation and for dynamic power control, hence it is very important to have the correct values. For that, you can set the rx_epre_offset parameter to the gain of your LNA. The same applies for NR rx_epre_offset