Hi All,
I have been dealing with a weird issue in the past couple of days. I needed to quickly check something about some phones, therefore I created an Osmocom CNI based 2G network. I have done this multiple times in the past even with OsmocomBB transceiver, however in the past some years I was not active in 2G, was more focused on 4G. I was very happy to see, that all familiar things I initially liked about osmocom are still in place/improved a lot (meaningful config files, simple VTY interface, a LOT more and better documentation). So the network is up and running fine, the setup consists of a laptop and a USRP B210 without GPSDO.
Then I tried to attach some phones to it, and hit an issue: * Samsung S6, S7 - does not detect the network, even if I put in a SIM card that has previously been in a phone that was already attached * iPhone X - does not detect the network
I first fiddled with the power settings, basically trying to turn it down a little bit (initially tx attenuation was at 0, so I turned it 10-20), because range is not needed, but I know distortion can happen when driving SDR HW to its max capacity. No change in the above.
Then I turned quickly to gr-gsm and rtl-sdr to see if I'm transmitting properly, the network was detected and C0 decoded properly. Next I tried with a Motorola C115 (yeah, I still have some lying around :)), and it attached to the network without any issue. Finally something that works as expected, right? Last but not least I tried with a Nokia 4.2 phone, which also attached to the network immediately without any issue.
So the bottom line is: what could cause this behavior? Is it possible that the USRP B210's accuracy is just not enough for newer phones? If yes how come the Nokia still attached, it is quite a recent phone with Qcomm chipset. I was also thinking if it is a Samsung vs Qualcomm thing, but then the iPhone should have at least detected the network. I tried with different SIM cards as well (not that it would make any difference...but I didn't have any better idea), and also with different bands and ARFCNs (900 and 1800). Antenna used is a VERT900. Configuration: unmodified standard config that came with the binary packages - except for MCC, MNC, rx gain, tx attenuation and max_power_red. I also tried to specify valid and also 'invalid' (unknown) MCC-MNC combinations to see if maybe newer Android/iOS only lists networks that advertise a known combination (again this would be very weird, but I just had no better ideas in the end).
Anybody have any recent experience with COTS MSs and OsmoBTS(-TRX) based network?
Any input is much appreciated, thanks.
Cheers, Domi
p.s. It is simply awesome to experience the power of opensource when dealing with 2G. Every step of the way above I was using software created and shared by you guys. It is a great feeling, had to share it :-).
On Wed, Feb 12, 2020 at 09:42:42AM +0100, Tomcsányi, Domonkos wrote:
p.s. It is simply awesome to experience the power of opensource when dealing with 2G. Every step of the way above I was using software created and shared by you guys. It is a great feeling, had to share it :-).
Thanks Domi!! I hope someone has answers your questions, I don't but wanted to wave back anyway \o_
~N
Dear Tomi, have you try to set attenuation set to OML and osmo-trx?
osmotrx rx-gain 30 osmotrx tx-attenuation oml
Im not sure but I saw your attenuation is set. :-)
I think I face the problem before but using Motorola C115/117 cannot connect, but it was resolved now long time ago with newer osmo-bts.
regards, Sandi
On Wed, Feb 12, 2020 at 7:10 PM Neels Hofmeyr nhofmeyr@sysmocom.de wrote:
On Wed, Feb 12, 2020 at 09:42:42AM +0100, Tomcsányi, Domonkos wrote:
p.s. It is simply awesome to experience the power of opensource when
dealing with 2G. Every step of the way above I was using software created and shared by you guys. It is a great feeling, had to share it :-).
Thanks Domi!! I hope someone has answers your questions, I don't but wanted to wave back anyway \o_
~N
Hello Sandi and Neels,
@Neels: :-) \o thanks.
@Sandi: Thank you for the idea. I have changed the attenuation to oml, and I could observe the following: All Qcomm based devices now see the network and with a bit of luck they could register: Xiaomi Mi5, Samsung A90 5G, iPhone X. However any Exynos based device (S6, S7, S8) simply refuses to even detect the network. Any time I put in a sysmocom SIM in a Qcomm based device it happily goes on the new network. On the other hand if the same SIM card is plugged into an Exynos device it shows No service and even with manual search it cannot detect the network.
I assume with other radio hardware (e.g. umTRX) there are no issues with Exynos devices, so it is most probably the USRP not being good enough I think.
However if anybody has any other ideas I’d still be happy to get any feedback and try things out :).
Cheers,
Domi
- febr. 12. dátummal, 14:20 időpontban Sandi Suhendro djks74@gmail.com írta:
Dear Tomi, have you try to set attenuation set to OML and osmo-trx?
osmotrx rx-gain 30 osmotrx tx-attenuation oml
Im not sure but I saw your attenuation is set. :-)
I think I face the problem before but using Motorola C115/117 cannot connect, but it was resolved now long time ago with newer osmo-bts.
regards, Sandi
On Wed, Feb 12, 2020 at 7:10 PM Neels Hofmeyr nhofmeyr@sysmocom.de wrote: On Wed, Feb 12, 2020 at 09:42:42AM +0100, Tomcsányi, Domonkos wrote:
p.s. It is simply awesome to experience the power of opensource when dealing with 2G. Every step of the way above I was using software created and shared by you guys. It is a great feeling, had to share it :-).
Thanks Domi!! I hope someone has answers your questions, I don't but wanted to wave back anyway \o_
~N
-- Best Regards, Sandi
hi,
On 2/12/20 8:15 PM, Tomcsányi, Domonkos wrote: [...]
I assume with other radio hardware (e.g. umTRX) there are no issues with Exynos devices, so it is most probably the USRP not being good enough I think.
i regulary use a b200/b210 series for tests, so i am quite sure it works when using a known good clock.
try sending a external clock to the device, for example a 10MHz gpsdo or another source which you can trust. sometimes even old lab equipment can be used as a source when it has a reference clock output (typically bnc).
enable using it by adding to your osmo-trx.cfg:
trx clock-ref external
the internal clock generation on generic sdr boards (which are not targeted at gsm/tdma systems) are often not precise enough. this is true for the basic usrp series as well as simple boards like the limesdr mini or usb(which you also can feed a clock).
in contrast: the limenet micro has a gpsdo on board for exactly this reason. the same is true for boards like the UmTRX, or when you add an precision source to a usrp. i think there is a module to add gps for the usrp.
However if anybody has any other ideas I’d still be happy to get any feedback and try things out :).
Cheers,
Domi
i hope this gets it working for you.
kind regards.
Hi Domi, Sorry for wrong spell. Wkwkk...
Have you try with GPSDO?
Some phone cannot sync or weak with the wave. Worth to try :)
regards, Sandi / DUO
On Thu, Feb 13, 2020, 02:16 Tomcsányi, Domonkos domi@tomcsanyi.net wrote:
Hello Sandi and Neels,
@Neels: :-) \o thanks.
@Sandi: Thank you for the idea. I have changed the attenuation to oml, and I could observe the following: All Qcomm based devices now see the network and with a bit of luck they could register: Xiaomi Mi5, Samsung A90 5G, iPhone X. However any Exynos based device (S6, S7, S8) simply refuses to even detect the network. Any time I put in a sysmocom SIM in a Qcomm based device it happily goes on the new network. On the other hand if the same SIM card is plugged into an Exynos device it shows No service and even with manual search it cannot detect the network.
I assume with other radio hardware (e.g. umTRX) there are no issues with Exynos devices, so it is most probably the USRP not being good enough I think.
However if anybody has any other ideas I’d still be happy to get any feedback and try things out :).
Cheers,
Domi
- febr. 12. dátummal, 14:20 időpontban Sandi Suhendro <
djks74@gmail.com> írta:
Dear Tomi, have you try to set attenuation set to OML and osmo-trx?
osmotrx rx-gain 30 osmotrx tx-attenuation oml
Im not sure but I saw your attenuation is set. :-)
I think I face the problem before but using Motorola C115/117 cannot connect, but it was resolved now long time ago with newer osmo-bts.
regards, Sandi
On Wed, Feb 12, 2020 at 7:10 PM Neels Hofmeyr nhofmeyr@sysmocom.de wrote:
On Wed, Feb 12, 2020 at 09:42:42AM +0100, Tomcsányi, Domonkos wrote:
p.s. It is simply awesome to experience the power of opensource when
dealing with 2G. Every step of the way above I was using software created and shared by you guys. It is a great feeling, had to share it :-).
Thanks Domi!! I hope someone has answers your questions, I don't but wanted to wave back anyway \o_
~N
-- Best Regards, Sandi
Hi Sandi and Joachim,
@Sandi: no worries about spelling :).
@both: thanks for the idea, it is what I was thinking about initially as well. I will check if I can get a good 10 MHz reference from some device. I was just informed however that Exynos devices do not need to be examined during my tests, so I’ll probably put this on hold for now. The lab at our HQ also has a UmTRX if I recall correctly, so worst case I could always ask them to do the tests. I just wanted to make sure it is the HW setup, not the config causing the trouble :). Now I’m confident that it is the lack of the clock source.
Thank you all for chiming in.
Cheers, Domi
- febr. 13. dátummal, 2:11 időpontban Sandi Suhendro djks74@gmail.com írta:
Hi Domi, Sorry for wrong spell. Wkwkk...
Have you try with GPSDO?
Some phone cannot sync or weak with the wave. Worth to try :)
regards, Sandi / DUO
On Thu, Feb 13, 2020, 02:16 Tomcsányi, Domonkos domi@tomcsanyi.net wrote: Hello Sandi and Neels,
@Neels: :-) \o thanks.
@Sandi: Thank you for the idea. I have changed the attenuation to oml, and I could observe the following: All Qcomm based devices now see the network and with a bit of luck they could register: Xiaomi Mi5, Samsung A90 5G, iPhone X. However any Exynos based device (S6, S7, S8) simply refuses to even detect the network. Any time I put in a sysmocom SIM in a Qcomm based device it happily goes on the new network. On the other hand if the same SIM card is plugged into an Exynos device it shows No service and even with manual search it cannot detect the network.
I assume with other radio hardware (e.g. umTRX) there are no issues with Exynos devices, so it is most probably the USRP not being good enough I think.
However if anybody has any other ideas I’d still be happy to get any feedback and try things out :).
Cheers,
Domi
- febr. 12. dátummal, 14:20 időpontban Sandi Suhendro djks74@gmail.com írta:
Dear Tomi, have you try to set attenuation set to OML and osmo-trx?
osmotrx rx-gain 30 osmotrx tx-attenuation oml
Im not sure but I saw your attenuation is set. :-)
I think I face the problem before but using Motorola C115/117 cannot connect, but it was resolved now long time ago with newer osmo-bts.
regards, Sandi
On Wed, Feb 12, 2020 at 7:10 PM Neels Hofmeyr nhofmeyr@sysmocom.de wrote: On Wed, Feb 12, 2020 at 09:42:42AM +0100, Tomcsányi, Domonkos wrote:
p.s. It is simply awesome to experience the power of opensource when dealing with 2G. Every step of the way above I was using software created and shared by you guys. It is a great feeling, had to share it :-).
Thanks Domi!! I hope someone has answers your questions, I don't but wanted to wave back anyway \o_
~N
-- Best Regards, Sandi
Another thing, usually even a bad clock is OK, when the phone can’t see any commercial network. Quite often they sync their clock on some commercial carrier on power-up and then can’t see any networks with bigger frequency offset. My solution is placing the phone in a metal cookie box that shields it from receiving any commercial network, but the SDR right next to it has enough power to get through. Then the phone starts a more exhaustive search with sweeping its TCXO over a bigger range. Once the phone has registered I take it out, and it keeps the connection without issues until phone or BS are restarted, then the same issue applies.
Ralph.
From: OpenBSC [mailto:openbsc-bounces@lists.osmocom.org] On Behalf Of Tomcsányi, Domonkos Sent: Thursday, February 13, 2020 10:07 AM To: Sandi Suhendro djks74@gmail.com Cc: openbsc openbsc@lists.osmocom.org Subject: Re: Commercial MSs do not see the network
Hi Sandi and Joachim,
@Sandi: no worries about spelling :).
@both: thanks for the idea, it is what I was thinking about initially as well.
I will check if I can get a good 10 MHz reference from some device. I was just informed however that Exynos devices do not need to be examined during my tests, so I’ll probably put this on hold for now. The lab at our HQ also has a UmTRX if I recall correctly, so worst case I could always ask them to do the tests. I just wanted to make sure it is the HW setup, not the config causing the trouble :). Now I’m confident that it is the lack of the clock source.
Thank you all for chiming in.
Cheers,
Domi
2020. febr. 13. dátummal, 2:11 időpontban Sandi Suhendro <djks74@gmail.com mailto:djks74@gmail.com > írta:
Hi Domi,
Sorry for wrong spell. Wkwkk...
Have you try with GPSDO?
Some phone cannot sync or weak with the wave. Worth to try :)
regards, Sandi / DUO
On Thu, Feb 13, 2020, 02:16 Tomcsányi, Domonkos <domi@tomcsanyi.net mailto:domi@tomcsanyi.net > wrote:
Hello Sandi and Neels,
@Neels: :-) \o thanks.
@Sandi:
Thank you for the idea. I have changed the attenuation to oml, and I could observe the following:
All Qcomm based devices now see the network and with a bit of luck they could register: Xiaomi Mi5, Samsung A90 5G, iPhone X.
However any Exynos based device (S6, S7, S8) simply refuses to even detect the network. Any time I put in a sysmocom SIM in a Qcomm based device it happily goes on the new network. On the other hand if the same SIM card is plugged into an Exynos device it shows No service and even with manual search it cannot detect the network.
I assume with other radio hardware (e.g. umTRX) there are no issues with Exynos devices, so it is most probably the USRP not being good enough I think.
However if anybody has any other ideas I’d still be happy to get any feedback and try things out :).
Cheers,
Domi
2020. febr. 12. dátummal, 14:20 időpontban Sandi Suhendro <djks74@gmail.com mailto:djks74@gmail.com > írta:
Dear Tomi,
have you try to set attenuation set to OML and osmo-trx?
osmotrx rx-gain 30 osmotrx tx-attenuation oml
Im not sure but I saw your attenuation is set. :-)
I think I face the problem before but using Motorola C115/117 cannot connect, but it was resolved now long time ago with newer osmo-bts.
regards,
Sandi
On Wed, Feb 12, 2020 at 7:10 PM Neels Hofmeyr <nhofmeyr@sysmocom.de mailto:nhofmeyr@sysmocom.de > wrote:
On Wed, Feb 12, 2020 at 09:42:42AM +0100, Tomcsányi, Domonkos wrote:
p.s. It is simply awesome to experience the power of opensource when dealing with 2G. Every step of the way above I was using software created and shared by you guys. It is a great feeling, had to share it :-).
Thanks Domi!! I hope someone has answers your questions, I don't but wanted to wave back anyway \o_
~N
Hello Ralph,
Good idea, thank you for the feedback. I'll test this theory as soon as I'm back home next week. It makes a lot of sense to me, so I'm really curious to see if it works in my case as well.
Cheers, Domi
----- Original Message -----
From: "Ralph A. Schmid, dk5ras" ralph@schmid.xxx To: "Domonkos Tomcsányi" domi@tomcsanyi.net, "Sandi Suhendro" djks74@gmail.com Cc: "openbsc" openbsc@lists.osmocom.org Sent: Friday, February 14, 2020 9:01:05 AM Subject: RE: Commercial MSs do not see the network
Another thing, usually even a bad clock is OK, when the phone can’t see any commercial network. Quite often they sync their clock on some commercial carrier on power-up and then can’t see any networks with bigger frequency offset. My solution is placing the phone in a metal cookie box that shields it from receiving any commercial network, but the SDR right next to it has enough power to get through. Then the phone starts a more exhaustive search with sweeping its TCXO over a bigger range. Once the phone has registered I take it out, and it keeps the connection without issues until phone or BS are restarted, then the same issue applies.
Ralph.
From: OpenBSC [mailto:openbsc-bounces@lists.osmocom.org] On Behalf Of Tomcsányi, Domonkos Sent: Thursday, February 13, 2020 10:07 AM To: Sandi Suhendro djks74@gmail.com Cc: openbsc openbsc@lists.osmocom.org Subject: Re: Commercial MSs do not see the network
Hi Sandi and Joachim,
@Sandi: no worries about spelling :).
@both: thanks for the idea, it is what I was thinking about initially as well.
I will check if I can get a good 10 MHz reference from some device. I was just informed however that Exynos devices do not need to be examined during my tests, so I’ll probably put this on hold for now. The lab at our HQ also has a UmTRX if I recall correctly, so worst case I could always ask them to do the tests. I just wanted to make sure it is the HW setup, not the config causing the trouble :). Now I’m confident that it is the lack of the clock source.
Thank you all for chiming in.
Cheers,
Domi
- febr. 13. dátummal, 2:11 időpontban Sandi Suhendro < [
mailto:djks74@gmail.com | djks74@gmail.com ] > írta: Hi Domi,
Sorry for wrong spell. Wkwkk...
Have you try with GPSDO?
Some phone cannot sync or weak with the wave. Worth to try :)
regards, Sandi / DUO
On Thu, Feb 13, 2020, 02:16 Tomcsányi, Domonkos < [ mailto:domi@tomcsanyi.net | domi@tomcsanyi.net ] > wrote:
Hello Sandi and Neels,
@Neels: :-) \o thanks.
@Sandi:
Thank you for the idea. I have changed the attenuation to oml, and I could observe the following:
All Qcomm based devices now see the network and with a bit of luck they could register: Xiaomi Mi5, Samsung A90 5G, iPhone X.
However any Exynos based device (S6, S7, S8) simply refuses to even detect the network. Any time I put in a sysmocom SIM in a Qcomm based device it happily goes on the new network. On the other hand if the same SIM card is plugged into an Exynos device it shows No service and even with manual search it cannot detect the network.
I assume with other radio hardware (e.g. umTRX) there are no issues with Exynos devices, so it is most probably the USRP not being good enough I think.
However if anybody has any other ideas I’d still be happy to get any feedback and try things out :).
Cheers,
Domi
- febr. 12. dátummal, 14:20 időpontban Sandi Suhendro < [
mailto:djks74@gmail.com | djks74@gmail.com ] > írta: Dear Tomi,
have you try to set attenuation set to OML and osmo-trx?
osmotrx rx-gain 30 osmotrx tx-attenuation oml
Im not sure but I saw your attenuation is set. :-)
I think I face the problem before but using Motorola C115/117 cannot connect, but it was resolved now long time ago with newer osmo-bts.
regards,
Sandi
On Wed, Feb 12, 2020 at 7:10 PM Neels Hofmeyr < [ mailto:nhofmeyr@sysmocom.de | nhofmeyr@sysmocom.de ] > wrote:
On Wed, Feb 12, 2020 at 09:42:42AM +0100, Tomcsányi, Domonkos wrote:
p.s. It is simply awesome to experience the power of opensource when dealing with 2G. Every step of the way above I was using software created and shared by you guys. It is a great feeling, had to share it :-).
Thanks Domi!! I hope someone has answers your questions, I don't but wanted to wave back anyway \o_
~N
--
Best Regards,
Sandi
-
Joachim Steiger -
Neels Hofmeyr -
Ralph A. Schmid, dk5ras -
Sandi Suhendro -
Tomcsányi, Domonkos