[srslte-users] Some commercial UEs can't detect the enb

[Yi Chu]

Hi Cedric,

Thanks for this! I thought about the same issue and tried a few "valid" UK
PLMN but the results are the same. I just had a quick look at the list
20892 is actually in there and it belongs to "Association Plate-forme
Telecom" Not sure whether it has anything to do with Eurecom.

Regards
Yi

On Thu, 6 Aug 2020 at 09:49, Cedric Roux <cedric.roux at eurecom.fr> wrote:

> Hi,
>
> maybe also some phones are "locked" and will only
> accept certain PLMNs. 20892 may not be one of them.
>
> For the list of PLMNs, see eg.
> https://www.mcc-mnc.com/
>
> On 2020-08-06 10:39, Paul Sutton wrote:
> > Hi Yi,
> >
> > Here are a few generic things to check:
> >
> > 1) Make sure the entire signal bw is inside the band of use
> >      - the DL/UL frequencies you're using should be fine
> > 2) Check that there are no interfering signals on the frequencies of use
> >      - B1 and B7 are fully allocated in the UK
> > (https://www.spectrummonitoring.com/frequencies/#UK) so use a Faraday
> > cage or check for existing carriers
> > 3) use a GPSDO or external clock source, or make sure carrier frequency
> > offset is small enough
> >      - Are you using an external clock source or do you have access to
> > equipment to check the frequency accuracy?
> > 4) Enable logs on the eNodeB and check if PRACH is detected
> > 5) Try adjusting tx_gain, reducing it or increasing. If the UE sees low
> > power (<pmax threshold), it won't PRACH
> >
> > For the iPhone 7 case, you could compare PRACH, SIB1 and SIB2
> > configurations for differences between srsENB and OAI. You could also
> > add SIB3 configuration in case the UEs require it.
> >
> > Are you using the default config files for everything except EARFCN? If
> > not, could you share your config files?
> >
> > Best regards,
> > Paul
> >
> > On 05/08/2020 17:08, Yi Chu wrote:
> >> Dear community,
> >>
> >> I have been testing srslte with a few different commercial UEs, some
> >> worked perfectly and some couldn't find the enb after network search.
> >> I found several similar issues such as this one
> >>
> http://www.softwareradiosystems.com/pipermail/srslte-users/2019-November/003153.html
> >> <
> http://www.softwareradiosystems.com/pipermail/srslte-users/2019-November/003153.html>
>
> >>
> >> but none of these really reached a conclusion. Here is my setup:
> >>
> >> A Ubuntu 18.04 laptop, srsenb and srsepc on the physical machine. I
> >> have been testing VoLTE as well so I have Open5GS (nextepc) running on
> >> a virtual machine, and I switch between the two EPC frequently. I have
> >> tested Band 7 DL=2.65GHz and UL=2.53GHz, also Band 1 DL=2.16GHz and
> >> UL=1.97GHz. The radio is a USRP B205mini (main USRP) and a USRP X300.
> >> PRB is 25. The USIM is from opencells. One the same laptop I have a
> >> working OAI (enb+epc) as well so I also run this setup to test the UEs.
> >>
> >> I have tested 6 commercial smartphones and here are the results.
> >> 1. Huawei P30 with stock Android 10 (unroot): so far the most
> >> favourable UE. It works with srsenb+srsepc, srsenb+open5gs, and OAI
> >> enb+epc, both Bands 1 and 7, and two mcc/mnc combinations 00101 and
> 20892.
> >>
> >> 2. IPhone 7 with IOS 12: it starts to get odd from here. It works with
> >> OAI enb+epc on both LTE bands, with mcc/mnc 20892. Once I switch to
> >> srsenb+srsepc, the UE can't find the enb in network search.
> >>
> >> 3. Samsung S5: I first tested it when it had the stock Android 4
> >> (unroot and yes it's old), it worked fine with srsenb+srsepc and OAI
> >> enb+epc, mcc/mnc=20892, band 7. The I flashed Lineage 16 (Android 9,
> >> unroot) on it and updated the firmware, the UE stops seeing either
> >> srsenb or OAI enb.
> >>
> >> 4. There are three UEs that can't find either srsenb or OAI enb on
> >> either LTE bands in network search. MI Mix2 (Android 8, unroot),
> >> Samsung A10 (Android 9, unroot) and Samsung A20e (Android 10, root).
> >> The Samsung UEs don't seem to support mcc=001 so I have tested 20892
> >> and but no luck. I'm using the same USIM which just worked on the
> >> Huawei UE. I have also tested these with USRP X300 but the results are
> >> the same.
> >>
> >> I have no clue what could cause the inconsistency of the IPhone 7, the
> >> results of the Samsung S5 is very strange as well, it looks like
> >> updating the firmware has made some impact.
> >>
> >> Anyone has any ideas of further tests/debug I can do, please let me
> >> know, many thanks!
> >>
> >> Best regards
> >> Yi
> >>
> >>
> >> _______________________________________________
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> >> srslte-users at lists.softwareradiosystems.com
> >> http://www.softwareradiosystems.com/mailman/listinfo/srslte-users
> >
> > --
> > ________________________________________________________________
> > Paul Sutton Ph.D.
> >
> > Software Radio Systems (SRS)
> > http://www.softwareradiosystems.com
> > paul at softwareradiosystems.com
> >
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> > ________________________________________________________________
> >
> >
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