Me and My LimeSDR USB

Hi EveryOne,

I received my LimeSDR about 2 months ago and then I spend 300 hours with it to figure out how to made it works for 4G LTE, I try many thing srsLTE, openairinterface, open5gs, openLTE but nothing work. until last week I decide to made it more serious so I put my LimeSDR in custom alumunium case, with a silent fan, a decent swithching PSU (actually its a former PSU from internet modem (12v 3A)). and then I install ubuntu 18.04 in a small SSD drive (128GB).
then as usual (I do this a thousand time :joy: :joy:) install soapySDR, install LimeSuite and last off course srsLTE.
after that I changed srsenb.conf file to work with band 7 FDD
what happend ?
for the first time I get Test PLMN 001-01 network on my Handphone. :heart_eyes: :heart_eyes: :heart_eyes: :heart_eyes:
I changed from endb 5o to 100 (I think its mean 20MHz Bandwith) without any single problem and I run it for 100 hours non stop and I still can see the network from at least 5 type of handphone.
so what I want to tell is old electronics stories about heat and power supply. dont take it lightly. I try my best to upload foto and screen shoot of my terminal after I can install screen capture application :face_with_hand_over_mouth: :face_with_hand_over_mouth:
just to be clear I start use LimeSDR without no knowledge of linux ( I spend 2 days try to install ubuntu in UEFI PC) so dont ask me technical question about ubuntu, Lime suite etc I just copy and paste person. but I try my best to help and report more with picture and measurement test.

as You can see from above screenshot ubuntu 18.04 and srsLTE need 8GB RAM almost 40% from my CPU capacity (i5-2500K overclock to 4.6GHz). in 2x2 MIMO with n_prb 75, tm = 2, nof_ports = 2 the usb soar up to 122Mb.

2 Likes

So true. Power supply is particularly important with LimeSDR-USB and it can operate fine via USB supply, but provided that port supplies sufficient current and the cable of is good quality and not damaged, hence minimal voltage drop. Depending upon the application and environment, cooling and screening can also be very important.

Are you just using two directly cabled antennas? If so, you may find you get improved performance using a duplexer plus a single antenna, since blocking effect of Tx will be reduced.

Congratulations and thanks for sharing!

Hi Andrew,
THank You for Your sugestion USD40 for duplexer is good investment.
there is a few thing unclear about srsLTE and LimeSDR USB

  1. I found after 2 times try if I only install soapy, limesuite and srsLTE what ever I do, its not work.
    (off course with all dependencies and ubuntu low latency) but then I installs UHD, BOOM "Test PLMN 001-01 appear in my handphone)
    Why ?
  2. lack of documentation,
    what I need to do for missing file in cmake stages, what I expected after I write “sudo srsenb” even the self test or any test in lime suite need some times to understand.
    perhaps it all about myself but I believe many owner LimeSDR have some problem.

No idea. You shouldn’t need UHD. The path should be srsLTE >> SoapySDR >> Lime Suite >> LimeSDR.

We are working on direct integration, which will remove SoapySDR in the path. This should provide certain benefits, including having more control over SDR configuration (being vendor and platform neutral means that you can’t access certain functionality if you go via SoapySDR).

I’m not sure what this means. We don’t develop srsLTE and you can find the project documentation at:

https://docs.srslte.com/en/latest/index.html

Once direct support (without SoapySDR) is merged we’ll look to put together a how-to guide.

Hi Andrew,

Sorry for wrong door complaint,
I happy read You and Your team build lime suite without soapy I hope its can bring a good improvement for now I feel use combination of soapy, lime suite, srslte isn’t very easy to use.
btw I corrected my claim that I need to use UHD to made limeSDR USB + Soapy SDR + SrsLTE to work. the right one is I need to use only srsLTE ver 19.12
I have try all 20 version include the 20.04.2 ver its not work.

this is far from my start but if posible could You made the procedure for test and running any sample in limesuite more convenience I suppose someone can choose the file and push start button is convenience. :rofl: