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:
- Couldn’t open: enb.conf
- 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
1 Like
I use LimeSDR for LTE with no problem it’s been a year, without duplexer and without GPSDO!
Let’s improve your network:
1- Give preference to Open5GS instead of SRSEPC; Open5GS is more stable to run over long durations, SRS developer himself says SRSEPC is for testing purposes only.
2- Use lower frequencies; LimeSDR has the highest power between 500 and 900MHz, I like to use it at 800MHz (B20) (EARFCN 6400)[use LNAL and BAND1] between 25 and 75PRBs… If you want to use high frequencies, high PRBs, you need to adjust the PPM offset (adjusting VCTCXO by LimeSuiteGUI can help) but better result; use GPSDO, but at high frequencies you will do better with an amplifier linear.
3 - Assuming you not have duplexer, increase your cellular device’s TX power (pusch), you can demand more power RF from your mobile by editing p0_nominal_pusch in your srsenb sib.conf file.
4- Use the maximum of 63 in your tx_gain of srsenb.conf, above that you will get a saturated signal, in your rx_gain use between 0-10 if your test is indoor.
5- Position your antenna 90 degrees apart to avoid arbitrary interference. Ex.: |_
6- Adjust your time_adv_nsamples to get the most accuracy from your Timing Advance, if this is wrong you will have too many re-connections, as the delay is time-phased, For me it works well with value 60.
7 - If when connecting you don’t get internet, it’s because your firewall is blocking the sgw, so run: iptables -F && iptables -t nat -F && iptables -t mangle -F && echo 1 > /proc/sys/net/ipv4/ip_forward && iptables -t nat -A POSTROUTING -o enp4s0 -j MASQUERADE (replace enp4s0 for your interface)
for details on how to create a network with open5gs see: https://open5gs.org/open5gs/docs/tutorial/01-your-first-lte/
ps: My English was translated from Portuguese, so there may be inconsistencies. =)
Thank you very much for suggestion.
I have try with OAI and srsRAN, but never with Open5GS.
OAI has some runtime error that I didn’t managet to fix.
I will setup Ubuntu 20 and try to run LimeSDR with Open5GS.