[srslte-users] enb falling apart for n_prb>50

Thu Mar 25 14:36:28 UTC 2021

Dear All,

I was trying to monitor the performances of the enb varying the n_prb
parameter.
In theory, for my understanding, the bandwidth and transfer should go UP
increasing n_prb. This is what I see up to n_prb=50, but with 75 or 100 I
am struggling to attach the UEs and they drop the connection very quickly
making it impossible to conclude an iperf test...

What can it be in your opinion? Tx/Rx interference? PC and/or SDR board
performance?

Something that I noticed is a weird sequence in the stout (see below): For
n_prb<=50 the " ==== eNodeB started === " message is at the end of all the
messages (after actual clock rate and setting frequency).
For the n_prb=75 (and same for 100) these messages are inverted and seem
that the eNodeB is started before setting the frequency?
Could this be a hint of wrong timings somewhere?

Cheers
---------------------------------------------------------------------------------------------------------

bts at bts-ThinkPad-L460:~$ sudo srsenb --enb.n_prb 50

[sudo] password for bts:

---  Software Radio Systems LTE eNodeB  ---

Reading configuration file /home/bts/.config/srslte/enb.conf...

Built in Release mode using commit ff84d7779 on branch fixing_enb_20_10.

/home/bts/srsLTE/srsenb/src/enb_cfg_parser.cc.890: Force DL EARFCN for cell
PCI=1 to 2525

Opening 1 channels in RF device=default with args=default

[INFO] [UHD] linux; GNU C++ version 7.5.0; Boost_106501;
UHD_3.15.0.0-62-g7a3f1516

[INFO] [LOGGING] Fastpath logging disabled at runtime.

Opening USRP channels=1, args: type=b200,master_clock_rate=23.04e6

[INFO] [B200] Detected Device: B200

[INFO] [B200] Operating over USB 3.

[INFO] [B200] Initialize CODEC control...

[INFO] [B200] Initialize Radio control...

[INFO] [B200] Performing register loopback test...

[INFO] [B200] Register loopback test passed

[INFO] [B200] Asking for clock rate 23.040000 MHz...

[INFO] [B200] Actually got clock rate 23.040000 MHz.

Setting frequency: DL=881.5 Mhz, UL=836.5 MHz for cc_idx=0

==== eNodeB started ===

Type <t> to view trace

q

Stopping ..

---  exiting  ---

bts at bts-ThinkPad-L460:~$ sudo srsenb --enb.n_prb 75

---  Software Radio Systems LTE eNodeB  ---