[srslte-users] Pi 4 srsLTE

[mark h]

Kenny,
I have been trying to get SRSUE and ENB to run on Pi-4's and have been
experiencing the same issue. When I moved to a faster SBC (UP^2) board I
was able to get both ENB and UE to work with the same settings. If I had to
guess I feel the latency on the Pi introduces timing issues and it cannot
establish the scheduling connection. We are trying to compile a real-time
Kernel to reduce the latency so we will see what happens.

I have also been struggling to get higher bandwidths using the LimeUSB's
with i7 and i5 laptops but get a real stable connection that runs for hours
at 1-2 MBPS. one thing I have found is that the signal cleans up
significantly when I put the governor in performance mode rather than on
demand. I also no longer get late errors. I have attached a couple of
images that show a change in the signal when the governor is changed. You
can see the significant jump in SNR. I also see a bandwidth increase when
running a IPERF3 test.

Summery of things I have found got me closer:
Cool and overclock the Pi
Set cpu governor to "performance"
Ensure the Pi has plenty of power
power the LimeSDR externally
Build SRSLTE and dependencies from source

setup-1: Not working fails at the same point yours is but ENB signal looks
good on the SPEC-AN
Pi-4
LimeUSB (on an externally powered USB)
Raspian latest Distro

Built from source:
SRSLTE 20.04
SoapySDR 0.7.01 (I had issues building the mos recent release they changed
a variable type and SRSLTE no longer builds)
LimeSuite 20.01

Setup-2: working at Nprb=15
Up^2 SBC
LimeUSB (on an externally powered USB)
ubuntu 18.04

Built from source:
SRSLTE 20.04
SoapySDR 0.7.01 (I had issues building the mos recent release they changed
a variable type and SRSLTE no longer builds)
LimeSuite 20.01


Hope this helps.

Mark



On Wed, May 6, 2020 at 11:51 AM Andre Puschmann <
andre.puschmann at softwareradiosystems.com> wrote:

> Kenneth,
>
> frankly speaking we don't do much over-the-air testing ourselves with
> the Pi4. All success or failure stories so far have been from users on
> the list.
>
> Anyway, we'll have a look into this over the next days.
>
> Thanks
> Andre
>
> On 6/5/20 15:49, Kenneth Barlee wrote:
> > Hey guys
> >
> > I have been having a play with a Pi 4B /4GB rev 1.2 running the new
> > Ubuntu Pi Server 20.04 x64 image, and trying to get srsLTE working. I
> > know several others have been talking about trying this, but haven't
> > noticed my issue coming up elsewhere.
> >
> > I started with the latest versions of UHD, SoapySDR, LimeSuite, srsLTE
> > (commit ID e3e38482100f5bf13f15af3bc09df882e937bc60). Everything
> > compiles happily (no need to change those lines in CMakeLists.txt), and
> > the srsenb/srsepc software runs successfully (after an initial wait of
> > ~5 mins after first launch for any change in n_prb). However, no phone
> > is able to fully connect when using a USRP B210/ LimeSDR-USB/
> > LimeSDR-Mini. It seems to start the attach, and there is a core
> > handshake, but the core reports that the "UE is not ECM connected" and
> > the UE never shows the signal bars.
> >
> > Decided to roll the Pi back to srsLTE v19.12, commit ID
> > d045213fb9cbf98c83c06d7c17197a9dcbfddacf, as I have been running this on
> > my desktop for a while now, and know it is stable. Again, this compiles
> > without issue. With this version, a phone will join a USRP B210 (not the
> > LimeSDRs, but that is probably another issue). It seems relatively
> > stable, and can continue running for several hours with a phone attached
> > running internet ping tests.
> >
> > I have attached logs and PCAPs for the two setups.
> >
> > A potentially related sidenote, with both srsenb versions, and all
> > radios, "SCHED: Could not transmit RAR within the window (RA TTI=2591,
> > Window=10, Now=2608)" type messages appear repeatedly in the terminal.
> > Running cellmapper on the phone, the LTE timing advance is estimated to
> > be '~250m' when using the USRP, but over '3.5km' with the LimeSDRs. This
> > is likely one of the reasons the LimeSDRs do not work with srsLTE v19.12.
> >
> > For reference, the UE used was a Samsung S20 Ultra 5G; LTE B3 earfcn
> > 1934, n_prb=15, SISO tm=1 nof_ports = 1.
> >
> > Has anybody experienced similar? Happy to do more testing if it helps
> > with debugging!
> >
> > Thanks
> >
> >
> > Kenny Barlee | Research Associate
> > Software Defined Radio Research Laboratory
> > Department of Electronic and Electrical Engineering
> > University of Strathclyde
> >
> > _______________________________________________
> > srslte-users mailing list
> > srslte-users at lists.softwareradiosystems.com
> > http://www.softwareradiosystems.com/mailman/listinfo/srslte-users
> >
>
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