RX sensitivity with Lime SDR mini 2.0

[gabtas]

Issue Description

I’m characterizing the RX sensitivity of an eNodeB based on srsRAN and LimeSDR mini 2.0; the sensitivity with Lime SDR mini 2.0 is 10dB worse than the one with another SDR.

Setup Details

I have a RFFE which includes a SAW duplexer for UL and DL isolation. I use a reference UE (evk of LTE module) and a step attenuator in order to tune the path loss for the 95% of throughput drop. The srsRAN settings are the same (ie: Band 5 850MHz, 25RB (5MHz), rx_gain=40) and the TX power level (DL) is adjusted at the same level.

srsRAN version 22.04-r0

Actual Behaviour

By comparing the eNodeB (UL) sensitivity achieved with LimeSDR mini 2.0 with the one achieved with another SDR, I can measure a sensitivity reduction of about 10dB.

Expected Behavior

The NF estimation is around 15dB which is much higher than the 2dB of the LMS7002M transceiver. I’m wondering if there is a particular setting in srsRAN enb.conf file I have to apply in the case of LimeSDR mini 2.0. Maybe the default IF filtering is not optimized for Lime?

Thanks in advance for your support