LimeSDR with srsenb

Hi,

I have found it difficult to run srsenb on Ubuntu 20.04.
I am getting error showed on the image attached.
As shown on image I can see LimeSDR listed but uhd_find_devices returns “No UHD Devices Found”.

That’s because a LimeSDR is not a USRP, hence cannot be used by UHD in this way.

This application note shows how to configure is to use SoapySDR with LimeSDR hardware:

https://docs.srsran.com/en/latest/app_notes/source/pi4/source/index.html

Hi,

I have two runtime issues when running srsenb:

  1. Couldn’t open: enb.conf
  2. Soapy selects wrong device

Srsepc works fine.

Please find attached snapshot.
Any idea how to fix that?

Thansk for your answer it works fine with SoapySDR.
Now I can run SoapySDRUtil --probe and see LimeSDR USB device.

Issue that remains is that I can not see my private network when I search it with my mobile phone (Samsung Galaxy S20+).

Could you tell me how to know if I connected antennas to the right connector?

I connected following antennas: TX1_1, TX2_1, RX1_H, RX2_H.

When I run srsENB with:
sudo srsenb ~/.config/srsran/enb.conf --expert.lte_sample_rates=true --rf.dl_earfcn 1934
DL EARFCN is set to 1934 because I am in Europe and LTE is on 1800MHz.
I can see that Rx and Tx antennas are set to LNAL and BAND1, please find snapshot attached.

How LNAL and BAND1 are mapped to the LimeSDR USB antenna connectors?

I have finally menaged to attach with Samsung Galaxy UE to my private network but connection is very unstabile.

In order to configure EPC, ENB to work with LimeSDR I have followed srsRAN Documentation, Release 21.10 (section: 5.2 COTS UE).

Could you tell me how this issue can be fixed?

I connected very good antennas with 38dBi:

Here is my configuration:
#####################################################
[rf]
#dl_earfcn = 3350
tx_gain = 80
rx_gain = 40
device_name = soapy
#device_args = auto
device_args = rxant=LNAH,txant=BAND1
#####################################################
[mme]
mme_code = 0x1a
mme_group = 0x0001
tac = 0x0007
mcc = 901
mnc = 70
mme_bind_addr = 127.0.1.100
apn = srsapn
dns_addr = 8.8.8.8
encryption_algo = EEA0
integrity_algo = EIA1
paging_timer = 2
request_imeisv = false

Two things which may help are a duplexer and external reference clock.

I’m very unsatisfied with LimeSDR. I will probbubly try with another hardware solution.
I’m able to connect UE to LimeSDR-srsENB 1 out of 10 times.
In other cases in can’t see network or it can’t attach.

I have also added additional power supply (9V 3A), but it hasn’t improved stability.

Software srsRAN run withaout any errors but it is very difficult to attach.

Without a duplexer the performance may be severely compromised, since you have a wideband SDR with no filtering and the base station transmit signal coupling back into receive. This would be precisely the same with any SDR that does not integrate RF front-end filtering.

Same goes with external reference clock and ideally this would be GPS locked or maybe an OCXO.

A wideband SDR with no external reference or RF front-end + software does not equal an LTE base station. You may be lucky and get good results, e.g. of the on-board oscillator is not far off and the antennas set up such to minimise Tx->Rx coupling, but it’s not guaranteed. Stability issues can also sometimes result from O/S issues, e.g. process scheduling and USB.

Could you recommend me duplexer for RF filtering?

I find this one:

Also please give me a suggestion for external reference clock?
I am not experienced in ti.

Thanks,
Nemanja

Numerous people have been successful using Leo Bodnar clocks:

http://www.leobodnar.com/shop/index.php?main_page=product_info&cPath=107&products_id=301

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