[srslte-users] USRP B210 doesn't work with "2 ports, 100 PRBs"

Sat Aug 1 01:50:09 UTC 2020

Hi everyone,

I am new to srsLTE and any help would be appreciated. I am trying to set up
an LTE ENB with 2 ports and 100 PRBs. I have followed all steps described
in
the github page but UE cannot find any cell in the corresponding frequency.

*Setup Details:*
I am using Ubuntu 18.04, srsLTE release_20_04, and UHD release_03_09_07.
The CPU of the ENB machine is Intel Core i5-7300U CPU @ 2.60GHz × 4.
For hardware, I have tried both USRP B210 and USRP X310 as ENB with 2 ports
and 100 PRBs. They act differently but neither of them works. For the UE
side, I
use USRP B210 and run "pdsch_ue -f 2685000000" to test the ENB.

*Issue Description: *
USRP B210 works well with "2 ports, 50 PRBs" or "1 port, 100 PRBs". In
these
cases, the UE can find the cell and decode PBCH correctly. The TX LED on
USRP
is red, which means it is transmitting signals.
When I set it to "2 ports, 75 PRBs",  the UE cannot find the cell and
output "Could
not find any cell in this frequency." But the TX LED on USRP is still red.
And then after
several seconds, the srsenb outputs an error "ERROR: timed out while
receiving samples
from UHD".
When I set it to "2 ports, 100 PRBs",  the UE cannot find the cell and
output "Could
not find any cell in this frequency." The TX LED on USRP only blink red
lights once
around every 10 seconds. And then after around 1 hour , the srsenb outputs
an error
"ERROR: timed out while receiving samples from UHD".

You can find blow the log files.
------------------------------------------------------------------------------------------------------------
*"2 ports, 50 PRBs"  :*
*sudo srsenb /etc/srslte/enb.conf*
linux; GNU C++ version 7.5.0; Boost_106501; UHD_003.009.007-0-g50839059

---  Software Radio Systems LTE eNodeB  ---

Reading configuration file /etc/srslte/enb.conf...

Built in Release mode using commit e3e384821 on branch HEAD.

Opening 2 channels in RF device=default with
args=serial=31C0427,num_recv_frames=64,num_send_frames=64
Opening USRP channels=2, args:
serial=31C0427,num_recv_frames=64,num_send_frames=64,master_clock_rate=23.04e6
-- Detected Device: B210
-- Operating over USB 3.
-- Initialize CODEC control...
-- Initialize Radio control...
-- Performing register loopback test... pass
-- Performing register loopback test... pass
-- Performing CODEC loopback test... pass
-- Performing CODEC loopback test... pass
-- Asking for clock rate 23.040000 MHz...
-- Actually got clock rate 23.040000 MHz.
-- Performing timer loopback test... pass
-- Performing timer loopback test... pass
--     1) catch time transition at pps edge
--     2) set times next pps (synchronously)

==== eNodeB started ===
Type <t> to view trace
Setting frequency: DL=2685.0 Mhz, UL=2565.0 MHz for cc_idx=0
^CStopping ..
---  exiting  ---

------------------------------------------------------------------------------------------------------------
*"2 ports, 50 PRBs"  :*
*./lib/examples/pdsch_ue -f 2685000000 -a "serial=3199405"*
linux; GNU C++ version 7.5.0; Boost_106501; UHD_003.009.007-0-g50839059

Opening RF device with 1 RX antennas...
Opening USRP channels=1, args: serial=3199405,master_clock_rate=23.04e6
-- Detected Device: B210
-- Operating over USB 3.
-- Initialize CODEC control...
-- Initialize Radio control...
-- Performing register loopback test... pass
-- Performing register loopback test... pass
-- Performing CODEC loopback test... pass
-- Performing CODEC loopback test... pass
-- Asking for clock rate 23.040000 MHz...
-- Actually got clock rate 23.040000 MHz.
-- Performing timer loopback test... pass
-- Performing timer loopback test... pass
Starting AGC thread...
Tunning receiver to 2685.000 MHz
Searching for cell...
 Found Cell_id:   0 FDD, CP: Normal  , DetectRatio= 0% PSR=0.00, Power=-inf
dBm
*Found Cell_id:   1 FDD, CP: Normal  , DetectRatio=100% PSR=7.85, Power=6.7
dBm
 Found Cell_id:   0 FDD, CP: Normal  , DetectRatio= 0% PSR=0.00, Power=-inf
dBm
Decoding PBCH for cell 1 (N_id_2=1)
Setting sampling rate 11.52 MHz
 - Type:            FDD   7.4, FrameCnt: 0, State: 1
 - PCI:             1
 - Nof ports:       2
 - CP:              Normal
 - PRB:             50
 - PHICH Length:    Normal
 - PHICH Resources: 1/6
 - SFN:             628
Decoded MIB. SFN: 628, offset: 3
          CFO: -733.72 Hz
         RSRP: +43.9 dBm | +40.4 dBm
          SNR: +25.9 dB
           TM: 2
           Rb:   0.03 /   0.14 /   0.36 Mbps (net/maximum/processing)
   PDCCH-Miss:  0.00%
   PDSCH-BLER:  0.00%
         TB 0: mcs=2; tbs=144
         TB 1: mcs=0; tbs=0
Press enter maximum printing debug log of 1 subframe.

          CFO: +12656.98 Hz
         RSRP: +37.6 dBm | +33.3 dBm
          SNR:  +2.3 dB
           TM: 2
           Rb:   0.04 /   0.14 /   0.03 Mbps (net/maximum/processing)
   PDCCH-Miss: 43.64%
   PDSCH-BLER:  0.49%
         TB 0: mcs=2; tbs=144
         TB 1: mcs=0; tbs=0
Press enter maximum printing debug log of 1 subframe.

------------------------------------------------------------------------------------------------------------
*"2 ports, 75 PRBs"  :*
*sudo srsenb /etc/srslte/enb.conf *
linux; GNU C++ version 7.5.0; Boost_106501; UHD_003.009.007-0-g50839059

---  Software Radio Systems LTE eNodeB  ---

Reading configuration file /etc/srslte/enb.conf...

Built in Release mode using commit e3e384821 on branch HEAD.

Opening 2 channels in RF device=default with
args=serial=31C0427,num_recv_frames=64,num_send_frames=64
Opening USRP channels=2, args:
serial=31C0427,num_recv_frames=64,num_send_frames=64,master_clock_rate=23.04e6
-- Detected Device: B210
-- Operating over USB 3.
-- Initialize CODEC control...
-- Initialize Radio control...
-- Performing register loopback test... pass
-- Performing register loopback test... pass
-- Performing CODEC loopback test... pass
-- Performing CODEC loopback test... pass
-- Asking for clock rate 23.040000 MHz...
-- Actually got clock rate 23.040000 MHz.
-- Performing timer loopback test... pass
-- Performing timer loopback test... pass
--     1) catch time transition at pps edge
--     2) set times next pps (synchronously)

==== eNodeB started ===
Type <t> to view trace
Setting frequency: DL=2685.0 Mhz, UL=2565.0 MHz for cc_idx=0
/home/pc6228/Fanyi/srsLTE/lib/src/phy/rf/rf_uhd_imp.c.1033: Error timed out
while receiving samples from UHD.

/home/pc6228/Fanyi/srsLTE/lib/src/phy/rf/rf_uhd_imp.c.1033: Error timed out
while receiving samples from UHD.

^CStopping ..
/home/pc6228/Fanyi/srsLTE/lib/src/phy/rf/rf_uhd_imp.c.1033: Error timed out
while receiving samples from UHD.

/home/pc6228/Fanyi/srsLTE/lib/src/phy/rf/rf_uhd_imp.c.1033: Error timed out
while receiving samples from UHD.

---  exiting  ---

------------------------------------------------------------------------------------------------------------
*"2 ports, 75 PRBs"  :*
*./lib/examples/pdsch_ue -f 2685000000 -a "serial=3199405"*
linux; GNU C++ version 7.5.0; Boost_106501; UHD_003.009.007-0-g50839059

Opening RF device with 1 RX antennas...
Opening USRP channels=1, args: serial=3199405,master_clock_rate=23.04e6
-- Detected Device: B210
-- Operating over USB 3.
-- Initialize CODEC control...
-- Initialize Radio control...
-- Performing register loopback test... pass
-- Performing register loopback test... pass
-- Performing CODEC loopback test... pass
-- Performing CODEC loopback test... pass
-- Asking for clock rate 23.040000 MHz...
-- Actually got clock rate 23.040000 MHz.
-- Performing timer loopback test... pass
-- Performing timer loopback test... pass
Starting AGC thread...
Tunning receiver to 2685.000 MHz
Searching for cell...
/home/pc6228/Fanyi/srsLTE/lib/src/phy/rf/rf_utils.c.207: Could not find any
cell in this frequency

Cell not found after 0 trials. Trying again (Press Ctrl+C to exit)
Searching for cell...
/home/pc6228/Fanyi/srsLTE/lib/src/phy/rf/rf_utils.c.207: Could not find any
cell in this frequency

Cell not found after 1 trials. Trying again (Press Ctrl+C to exit)
Searching for cell...
/home/pc6228/Fanyi/srsLTE/lib/src/phy/rf/rf_utils.c.207: Could not find any
cell in this frequency

Cell not found after 2 trials. Trying again (Press Ctrl+C to exit)
Searching for cell...
/home/pc6228/Fanyi/srsLTE/lib/src/phy/rf/rf_utils.c.207: Could not find any
cell in this frequency

Cell not found after 3 trials. Trying again (Press Ctrl+C to exit)
Searching for cell...
/home/pc6228/Fanyi/srsLTE/lib/src/phy/rf/rf_utils.c.207: Could not find any
cell in this frequency

Cell not found after 4 trials. Trying again (Press Ctrl+C to exit)
Searching for cell...

------------------------------------------------------------------------------------------------------------
*"2 ports, 100 PRBs"  :*
*sudo srsenb /etc/srslte/enb.conf *
linux; GNU C++ version 7.5.0; Boost_106501; UHD_003.009.007-0-g50839059

---  Software Radio Systems LTE eNodeB  ---

Reading configuration file /etc/srslte/enb.conf...

Built in Release mode using commit e3e384821 on branch HEAD.

Opening 2 channels in RF device=default with
args=serial=31C0427,num_recv_frames=64,num_send_frames=64
Opening USRP channels=2, args:
serial=31C0427,num_recv_frames=64,num_send_frames=64,master_clock_rate=23.04e6
-- Detected Device: B210
-- Operating over USB 3.
-- Initialize CODEC control...
-- Initialize Radio control...
-- Performing register loopback test... pass
-- Performing register loopback test... pass
-- Performing CODEC loopback test... pass
-- Performing CODEC loopback test... pass
-- Asking for clock rate 23.040000 MHz...
-- Actually got clock rate 23.040000 MHz.
-- Performing timer loopback test... pass
-- Performing timer loopback test... pass
--     1) catch time transition at pps edge
--     2) set times next pps (synchronously)

==== eNodeB started ===
Type <t> to view trace
Setting frequency: DL=2685.0 Mhz, UL=2565.0 MHz for cc_idx=0
^CStopping ..
---  exiting  ---

------------------------------------------------------------------------------------------------------------
*"2 ports, 100 PRBs"  :*
*./lib/examples/pdsch_ue -f 2685000000 -a "serial=3199405"*
linux; GNU C++ version 7.5.0; Boost_106501; UHD_003.009.007-0-g50839059

Opening RF device with 1 RX antennas...
Opening USRP channels=1, args: serial=3199405,master_clock_rate=23.04e6
-- Detected Device: B210
-- Operating over USB 3.
-- Initialize CODEC control...
-- Initialize Radio control...
-- Performing register loopback test... pass
-- Performing register loopback test... pass
-- Performing CODEC loopback test... pass
-- Performing CODEC loopback test... pass
-- Asking for clock rate 23.040000 MHz...
-- Actually got clock rate 23.040000 MHz.
-- Performing timer loopback test... pass
-- Performing timer loopback test... pass
Starting AGC thread...
Tunning receiver to 2685.000 MHz
Searching for cell...
/home/pc6228/Fanyi/srsLTE/lib/src/phy/rf/rf_utils.c.207: Could not find any
cell in this frequency

Cell not found after 0 trials. Trying again (Press Ctrl+C to exit)
Searching for cell...
/home/pc6228/Fanyi/srsLTE/lib/src/phy/rf/rf_utils.c.207: Could not find any
cell in this frequency

Cell not found after 1 trials. Trying again (Press Ctrl+C to exit)
Searching for cell...
/home/pc6228/Fanyi/srsLTE/lib/src/phy/rf/rf_utils.c.207: Could not find any
cell in this frequency

Cell not found after 2 trials. Trying again (Press Ctrl+C to exit)
Searching for cell...
/home/pc6228/Fanyi/srsLTE/lib/src/phy/rf/rf_utils.c.207: Could not find any
cell in this frequency

Cell not found after 3 trials. Trying again (Press Ctrl+C to exit)
Searching for cell...
/home/pc6228/Fanyi/srsLTE/lib/src/phy/rf/rf_utils.c.207: Could not find any
cell in this frequency

Cell not found after 4 trials. Trying again (Press Ctrl+C to exit)
Searching for cell...
/home/pc6228/Fanyi/srsLTE/lib/src/phy/rf/rf_utils.c.207: Could not find any
cell in this frequency

Cell not found after 5 trials. Trying again (Press Ctrl+C to exit)
Searching for cell...
/home/pc6228/Fanyi/srsLTE/lib/src/phy/rf/rf_utils.c.207: Could not find any
cell in this frequency

Cell not found after 6 trials. Trying again (Press Ctrl+C to exit)
Searching for cell...
/home/pc6228/Fanyi/srsLTE/lib/src/phy/rf/rf_utils.c.207: Could not find any
cell in this frequency

Cell not found after 7 trials. Trying again (Press Ctrl+C to exit)
Searching for cell...
/home/pc6228/Fanyi/srsLTE/lib/src/phy/rf/rf_utils.c.207: Could not find any
cell in this frequency

Cell not found after 8 trials. Trying again (Press Ctrl+C to exit)
Searching for cell...
/home/pc6228/Fanyi/srsLTE/lib/src/phy/rf/rf_utils.c.207: Could not find any
cell in this frequency

Cell not found after 9 trials. Trying again (Press Ctrl+C to exit)
Searching for cell...
/home/pc6228/Fanyi/srsLTE/lib/src/phy/rf/rf_utils.c.207: Could not find any
cell in this frequency

Cell not found after 10 trials. Trying again (Press Ctrl+C to exit)
Searching for cell...
/home/pc6228/Fanyi/srsLTE/lib/src/phy/rf/rf_utils.c.207: Could not find any
cell in this frequency

Cell not found after 11 trials. Trying again (Press Ctrl+C to exit)
Searching for cell...
/home/pc6228/Fanyi/srsLTE/lib/src/phy/rf/rf_utils.c.207: Could not find any
cell in this frequency

Cell not found after 12 trials. Trying again (Press Ctrl+C to exit)
Searching for cell...
/home/pc6228/Fanyi/srsLTE/lib/src/phy/rf/rf_utils.c.207: Could not find any
cell in this frequency

Cell not found after 13 trials. Trying again (Press Ctrl+C to exit)
Searching for cell...
/home/pc6228/Fanyi/srsLTE/lib/src/phy/rf/rf_utils.c.207: Could not find any
cell in this frequency

Cell not found after 14 trials. Trying again (Press Ctrl+C to exit)
Searching for cell...
/home/pc6228/Fanyi/srsLTE/lib/src/phy/rf/rf_utils.c.207: Could not find any
cell in this frequency

Cell not found after 15 trials. Trying again (Press Ctrl+C to exit)
Searching for cell...
/home/pc6228/Fanyi/srsLTE/lib/src/phy/rf/rf_utils.c.207: Could not find any
cell in this frequency

Cell not found after 16 trials. Trying again (Press Ctrl+C to exit)
Searching for cell...
/home/pc6228/Fanyi/srsLTE/lib/src/phy/rf/rf_utils.c.207: Could not find any
cell in this frequency

Cell not found after 17 trials. Trying again (Press Ctrl+C to exit)
Searching for cell...
^CSIGINT received. Exiting...
/home/pc6228/Fanyi/srsLTE/lib/src/phy/rf/rf_utils.c.207: Could not fin
------------------------------------------------------------------------------------------------------------

I observe that no matter how I set the number of PRBs and ports, the
master_clock_rate
of B210 is always automatically set to 23.04e6, which theoretically is not
sufficient for
"2 ports, 100 PRBs". It requires a master_clock_rate of  at least 40e6.
Is master_clock_rate the problem? Or if I change the master_clock_rate to a
number
larger than 40e6, will the problem be solved?

Also, is this a compatibility problem of srsLTE software versions?
*Please let me know if you have a proven working setting, where ENB is **2
ports and 100 PRBs.*

Please let me know if you need any necessary additional files.

Thank you,
Best,
Fan Yi
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