[srslte-users] srsUE not able to connect to real network

[srslte at cymaera.com]

Hi,

I'm running the currently latest stable version (20.10.1) of srsUE on my
computer (Ubuntu 20.04, equipped with an i7 9th gen CPU), trying to
connect to a real network - eNBs belonging to either one of two mobile
operators in my area, so I'm using a SIM card reader with the operators
respective SIM cards.
My RF frontend is the USRP B200, attached with a pair of whip antennas
and a (non-GPS calibrated) 10MHz external clock reference.

The srsUE is having a hard time scanning for compatible cells,
extracting their PLMNs, and mostly attaching. 
I see a large variance in different runs, both time-wise (ranging from
taking mere seconds, to a couple of minutes) and attach success rates
wise (ranging from not succeeding at all and simply retrying
indefinitely, to attaching and then immediately after printing the GW IP
address, disconnecting again). 
Everything radio-related seems to be "shaky". 

The errors messages I see on-screen and in logs are not consistent, but
I've gathered some of them here: 

1. Warning: Detected radio-link failure 

2. lib/src/phy/phch/ra_dl.c.639: Configuring resource allocation
3. lib/src/phy/phch/ra_dl.c.519: Not implemented codebook index
4. lib/src/phy/phch/ra_dl.c.526: Reserved codebook index
5. lib/src/phy/phch/ra_dl.c.590: Configuring MIMO PMI

6. Selected cell no longer suitable: going to RRC idle

7. Received RRC Connection Release (releaseCause: other) 

Also, the PSS powers I see are around -30 to -40 dbm (although, btw, I
believe this is a scaling bug when printing dbW values in a dbm field -
as I think it should show values around -60 to -70 dbm). 

My suspects so far have been clock timings, Rx/Tx powers, use of MIMO
(which the B200 doesn't have support for but I'm not trying to utilize,
though). 

I've tested lots of different approaches, but none of them helped thus
far. 
I'm running as sudo, with the cpu governor set to performance mode, and
tried different values for command-line arguments such as rx_gain,
tx_gain, time_adv_nsamples, freq_offset, and device_args such as
master_clock_rate and clock (internal/external). 

Any ideas what the problem might be? 
Thanks, 

Shisel
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