5G Signal properties

Wed Jun 10 10:43:02 UTC 2020

On Wed, Jun 10, 2020 at 06:39:55AM +0200, Sebastian Sjoholm wrote:
> Hi Nick,
> 
> Since the system is 5G NSA (none stand alone), only the user data is used
> with the 5G, the control data is still using LTE. Therefor if there are no
> active user data, the 5G NSA status would not be active, it will activate
> during data usage (this would be the normal behaviour). So, when the modem
> is idle (on LTE) you will not get 5G NR signal data.
> 
> The band info (TLV info) is not related as it is static modem info, and as
> we have noted now that this seems to be varied depending on the FW. I guess
> we need to wait a while until the commercial units are out to make final
> assumption where this will go.
> 
> Regards,
> Sebastian
> 
> 
> On Tue, Jun 9, 2020 at 11:21 PM Nick <mips171 at icloud.com> wrote:
> 
> > Hi Reinhard,
> >
> > A new development -- while on the 5G network with an active data
> > connection (MM connected and ifup on the interface) I could get the real 5G
> > values via the AT command, however the TLV was still missing from the
> > verbose output of ???dms-get-band-capabilities.  Still, UL/DL performance
> > was, disappointingly, still about what you would expect from one LTE band,
> > but that is probably its own topic.
> >
> > Here???s the AT command response:
> > at+qeng=???servingcell???
> > +QENG: ???servingcell???, ???NOCONN???
> > +QENG: ???LTE???,???FDD???,505,01,8C62D06,182,9410,28,5,5,7025,-78,-7,-51,15,-
> > +QENG:???NR5G-NSA???,505,01,839,-83,154,-12
> >
> > at+qeng=???servingcell???
> > +QENG: ???servingcell???, ???NOCONN???
> > +QENG: ???LTE???,???FDD???,505,01,8C62D06,182,9410,28,5,5,7025,-81,-8,-53,14,-
> > +QENG:???NR5G-NSA???,505,01,839,-93,60,-12
> >
> >
> > Best,
> > Nick

Hi all,
thanks for your updates on this.

How tight should the AT+QENG="servingcell" polling in ModemManager be
to avoid losing too many samples?

Perhaps it might also be possible to enable QMI NASSignalInfoIndication
in libqmi provided that NR5G-specific TLVs also exist there and you trust
my interpretation of their semantics...

Regards,
Reinhard

> >
> >
> > > On 10 Jun 2020, at 3:12 am, Reinhard Speyerer <rspmn at arcor.de> wrote:
> > >
> > > On Tue, Jun 09, 2020 at 08:50:10AM +1000, Nick wrote:
> > >> Hi Walter,
> > >>
> > >> I???m seeing a similar issue with my RM500Q-GL.  Can you please post
> > the output of: qmicli -p -d /dev/cdc-wdm0 --dms-get-band-capabilities
> > >>
> > >> Mine below for your reference.  You would note on mine, after the
> > Extended LTE bands, where we would expect to see the 5GNR band TLV
> > response, that it is absent. (Thanks to Sebastian for showing me that.)
> > However, I am currently not attached to a 5G network, nevertheless, when I
> > attempted this test while attached to a 5G network, I had the same result.
> > >>
> > >>
> > >> Best,
> > >> Nick
> > >>
> > >>
> > >> When I was on 5G
> > >> ---------------
> > >> AT+QENG="Servingcell"
> > >> +QENG: "servingcell","NOCONN???
> > >> +QENG:
> > "LTE","FDD",505,01,8B45502,349,1300,3,5,5,700B,-83,-10,-53,20,0,-150,-
> > >> +QENG: ???NR5G-NSA???,505,01,45,-32768,-32768,-32768 (note the negative
> > values for signal, equivalent to 0b1000000000000000)
> > >> --------------
> > >> Responses for AT+QENG 5GNR: Access Tech, MCC, MNC, PCID, RSRP, SINR,
> > RSRQ
> > >>
> > >
> > > Hi Nick,
> > >
> > > same over here when using a test network in 5G NSA mode:
> > >
> > > at+qeng="servingcell"
> > > +QENG: "servingcell","NOCONN"
> > > +QENG: "LTE","FDD",1,01,1A2D001,1,300,1,3,3,1,-87,-3,-67,23,255,-32768,52
> > > +QENG:"NR5G-NSA",1,01,500,-32768,-32768,-32768
> > >
> > > OK
> > >
> > > NASGetSignalInfo output for 5G NSA (from another test, still with the
> > RG500Q):
> > > +OK NASGetSignalInfo
> > 02040000000000140600bffaa8ffb600170400008000801802000080
> > >
> > > My assumption is that RSRP, SINR and RSRQ above would only be defined for
> > > 5G SA mode as can be seen from the qmicli -v --nas-get-signal-info
> > output here
> > > https://gitlab.freedesktop.org/mobile-broadband/libqmi/-/issues/32 .
> > >
> > > I tried to stay out of the "guessing 5G QMI TLVs" business but since we
> > > may never see a GobiAPI 2020 update here it goes anyway:
> > > TLV 0x17 = RSRP and SINR (scaled by 10 like for LTE(?)), TLV 0x18 = RSRQ.
> > >
> > > A TLV that looks a little bit easier to guess due to its unusual size:
> > > NASGetSystemInfo TLV 0x50 = 5GS TAC from TS 24.501 section 9.11.3.8.
> > >
> > > Regards,
> > > Reinhard
> >
> > _______________________________________________
> > ModemManager-devel mailing list
> > ModemManager-devel at lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/modemmanager-devel
> >

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