USRP B210 in band N79. BW40, 50M will not work.

[masao4511]

In my area, the spectrum available for private 5G is N79.

Of these, 40,50, and 60 BW can be used with the B210.
I tried 40 M and 50M, but I got the following error.

Examples

l5g@l5g-core-gnb:~$ sudo ~/srsRAN_Project/build/apps/gnb/gnb -c ~/srsRAN_Project/configs/gnb_rf_b200_tdd_n79_bw40.yml
--== srsRAN gNB (commit 9d5dd742a) ==--

The PRACH detector will not meet the performance requirements with the configuration {Format B4, ZCZ 0, SCS 30kHz, Rx ports 1}.
Lower PHY in quad executor mode.
srsRAN ERROR: Invalid configuration DU cell detected.
> Invalid Nof. PDCCH candidates monitored per slot for a DL BWP=39 exceeds maximum value=36
 (39 >= 36)

CONFIG
ru_sdr:
  device_driver: uhd
  device_args: type=b200,num_recv_frames=256,num_send_frames=256
#  srate: 23.04
  srate: 46.08 
#  srate: 61.44 
  otw_format: sc12
  tx_gain: 80
  rx_gain: 40

cell_cfg:
  dl_arfcn: 710004 #4.65G
  band: 79
  channel_bandwidth_MHz: 40
  common_scs: 30
  plmn: "00101"
  tac: 1
  pci: 1
  −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

BW60M works with srate: 61.44M.
However, the filter 56M warning is displayed and the communication speed is slower than the N78.
Examples

[INFO] [B200] Setting master clock rate selection to 'automatic'.
[INFO] [B200] Asking for clock rate 16.000000 MHz... 
[INFO] [B200] Actually got clock rate 16.000000 MHz.
[INFO] [MULTI_USRP] Setting master clock rate selection to 'manual'.
[INFO] [B200] Asking for clock rate 61.440000 MHz... 
[INFO] [B200] Actually got clock rate 61.440000 MHz.
[WARNING] [AD936X] Selected Tx sample rate (61.44 MHz) is greater than
analog frontend filter bandwidth (56 MHz).
[WARNING] [AD936X] Selected Rx sample rate (61.44 MHz) is greater than
analog frontend filter bandwidth (56 MHz).
Cell pci=1, bw=60 MHz, 1T1R, dl_arfcn=710004 (n79), dl_freq=4650.06 MHz, dl_ssb_arfcn=709536, ul_freq=4650.06 MHz

CONFIG
ru_sdr:
  device_driver: uhd
  device_args: type=b200,num_recv_frames=256,num_send_frames=256
#  srate: 23.04
#  srate: 46.08 
  srate: 61.44 
  otw_format: sc12
  tx_gain: 80
  rx_gain: 40
cell_cfg:  
  dl_arfcn: 710004 #4.65G
  band: 79
  channel_bandwidth_MHz: 60
  common_scs: 30
  

Can I use BW40,50 with N 79?

[robertfalkenberg]

Please try adding this snippet to your config as workaround:

cell_cfg:
  pdcch:
    dedicated:
      ss2_n_candidates: [0,0,1,2,0]

[masao4511]

Both bw40 and 50 MHz were confirmed to operate normally.
Thank you very much.
Cell pci=1, bw=40 MHz, 1T1R, dl_arfcn=729180 (n79), dl_freq=4937.7 MHz, dl_ssb_arfcn=729504, ul_freq=4937.7 MHz

[robertfalkenberg]

Thank you for the feedback!