Could not find any cell

joerichter-stash commented 3 years ago

Hello,

i would like to use the FalconGui for a SDR tech-demo, but unfortunately i am not able to find the cell in FalconGui.

To find the cell frequency and ID i used: https://github.com/JiaoXianjun/LTE-Cell-Scanner with an RTL-SDR: with the following command:

CellSearch -s 1810e6 -e 1830e6 -p 1

Output:

Detected a FDD cell! At freqeuncy 1815.2MHz, try 0
    cell ID: 376
     PSS ID: 1
    RX power level: -18.6699 dB
    residual frequency offset: -11389.2 Hz
                     k_factor: 1.00001

For FalconGui i used a Ettus B200, that i previously tested with Gqrx. I used the frequency and CID as input for FalconGui and got the following log:

QMetaObject::connectSlotsByName: No matching signal for on_actionDownlink_Plots_changed()
RF_Freq:  1.8152e+09
Creating Phy
SubframeWorkerThread ready
Spectrum View on
Opening RF device with 1 RX antennas...
[INFO] [UHD] linux; GNU C++ version 9.3.0; Boost_107100; UHD_3.15.0.0-release
[INFO] [B200] Loading firmware image: /usr/share/uhd/images/usrp_b200_fw.hex...
Opening USRP with args: type=b200,master_clock_rate=30.72e6
[INFO] [B200] Detected Device: B200
[INFO] [B200] Loading FPGA image: /usr/share/uhd/images/usrp_b200_fpga.bin...
[INFO] [B200] Operating over USB 3.
[INFO] [B200] Detecting internal GPSDO.... 
[INFO] [GPS] No GPSDO found
[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 30.720000 MHz... 
[INFO] [B200] Actually got clock rate 30.720000 MHz.
Starting AGC thread...
Tunning receiver to 1.8152e+09 Hz
Searching for cell...
Could not find any cell in this frequency
Cell not found after 0 trials
Searching for cell...
Could not find any cell in this frequency
Cell not found after 1 trials
Searching for cell...
Could not find any cell in this frequency
Cell not found after 2 trials
EyeCore: Exiting...
SubframeWorkerThread ended
Destroyed Phy

I have also tried this with several other Cells i have found with LTE-Cell-Scanner. A few times FalconGui found some PDCCH but discarded them without further information.

Can you help me with further information, what i am missing for this setup or how to debug it? May it be related to the usage of a B200?

Best regards, Joe

falkenber9 commented 3 years ago

Hi Joe,

could you please verify if the cell is found by the cell_search application that comes with srsLTE? If srsLTE is built as a subproject, you can find the binary in <build-dir>/srsLTE-build/lib/examples.

Best regards, Robert

joerichter-stash commented 3 years ago

Hi Robert,

Thanks for your help. cell_search from srsLTE solved the issue.

I noticed further, that if the base station signal is too weak (in my case < ~ -40dBm) the cell also could not be found in FalconGUI. But i guess this is normal behavior.

Thank you and best regards, Joe

falkenber9 / falcon

Could not find any cell #5