[srslte-users] UE attach but can't create VPN

[Andre Puschmann]

Hey Theo,

put the VPN issue aside for the moment. It's rather a LTE issue your
having that causes the connection to break.

Make sure your signals for both UL and DL are good. Check your antenna
config, the LNAH/BAND2 doesn't seem right for the EARFCN you are using.

Cheers
Andre


On 9/7/20 16:22, theo.gurgey wrote:
> ‌Hello,
>  
> I have successfully done my installation with srsLTE on one machine
> Ubuntu 18.04, with a LimeSDR mini. The LimeSDR mini is linked to the UE
> (LTE modem) with coaxial cable with -20 dB attenuation on RX side and
> -30 dB attenuation on TX side.
>  
> Since my UE has only one coax port, I use a splitter. 
>  
> The air conditioning next to the Lime cools it down, and the card is
> well connected to an USB 3 port.
>  
> I can launch srslte, and attach the UE to the network, even if the
> attach procedure can be fickle (see log file printed below).
>  
> However, I want to establish a VPN connection between my UE and a VPN
> server, but I can't !
> The VPN server receives the connexion request, it answers but the answer
> is not received by my UE. I can clearly see messages from both sides on
> the srslte machine, on the spgw interface, but it seems the LimeSDR
> doesn't send back the answer to the UE (see attached file
> srs_spgw_sgi.png). My UE retransmit perpetually connexion request so.
> Sometimes for a short period of time <1s, the packets are well received
> by the UE and then it overlaps.
>  
> The " [ERROR] Tx Calibration: MCU error 4 (SXT tune failed) " worried me
> but I don't know if it is the cause of my problems since I have seen
> many people having the same errors on forums.
>  
> What can I do? All suggestions are welcome.
>  
> Regards,
> Théo 
>  
>  
>  
>  
> ##########################  srs_spgw_sgi
> #######################################
>  
> srs_spgw_sgi1.jpg
> ##############################################################################
>  
>  
>  
> ##############################################################################
> ################################### enb log
> ####################################
> ##############################################################################
> ---  Software Radio Systems LTE eNodeB  ---
> 
> Reading configuration file /home/user/.config/srslte/enb.conf...
> 
> Built in Release mode using commit c892ae56b on branch master.
> 
> /home/user/SRS-LTE/srsLTE/srsenb/src/enb_cfg_parser.cc.883: Force DL
> EARFCN for cell PCI=1 to 6200
> 
> Opening 1 channels in RF device=soapy with args=rxant=LNAH,txant=BAND2
> Soapy has found device #0: addr=24607:1027, driver=lime, label=LimeSDR
> Mini [USB 3.0] 1D538755289563, media=USB 3.0, module=FT601, name=LimeSDR
> Mini, serial=1D538755289563,
> Selecting Soapy device: 0
> [INFO] Make connection: 'LimeSDR Mini [USB 3.0] 1D538755289563'
> [INFO] Reference clock 40.00 MHz
> [INFO] Device name: LimeSDR-Mini
> [INFO] Reference: 40 MHz
> [INFO] LMS7002M register cache: Disabled
> Setting up Rx stream with 1 channel(s)
> Setting up Tx stream with 1 channel(s)
> [INFO] RX LPF configured
> [INFO] Filter calibrated. Filter order-4th, filter bandwidth set to 5
> MHz.Real pole 1st order filter set to 2.5 MHz. Preemphasis filter not active
> [INFO] TX LPF configured
> Available device sensors:
>  - clock_locked
>  - lms7_temp
> Available sensors for Rx channel 0:
>  - lo_locked
> Setting Rx antenna to LNAH
> Setting Tx antenna to BAND2
> [ERROR] Tx Calibration: MCU error 4 (SXT tune failed)
> [INFO] Rx calibration finished
> State of gain elements for Rx channel 0 (AGC not supported):
>  - TIA: 9.00 dB
>  - LNA: 30.00 dB
>  - PGA: -4.00 dB
> State of gain elements for Tx channel 0 (AGC not supported):
>  - PAD: 45.00 dB
>  - IAMP: 0.00 dB
> Rx antenna set to LNAH
> Tx antenna set to BAND2
> 
> ==== eNodeB started ===
> Type <t> to view trace
> [INFO] RX LPF configured
> [INFO] Filter calibrated. Filter order-4th, filter bandwidth set to
> 11.52 MHz.Real pole 1st order filter set to 2.5 MHz. Preemphasis filter
> not active
> [INFO] TX LPF configured
> Setting frequency: DL=796.0 Mhz, UL=837.0 MHz for cc_idx=0
> RACH:  tti=9271, preamble=31, offset=13, temp_crnti=0x46
> 
> RACH:  tti=3571, preamble=42, offset=13, temp_crnti=0x47
> Disconnecting rnti=0x46.
> User 0x47 connected
> LRACH:  tti=9821, preamble=27, offset=13, temp_crnti=0x48
> Disconnecting rnti=0x48.
> Disconnecting rnti=0x47.
> RACH:  tti=9991, preamble=15, offset=13, temp_crnti=0x49
> RACH:  tti=9931, preamble=20, offset=13, temp_crnti=0x4a
> RACH:  tti=4221, preamble=21, offset=13, temp_crnti=0x4b
> User 0x4b connected
>  
> ##########################################################################
> ##########################################################################
> ##########################################################################
> 
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