Strange Mirkoitk 5G R16 Behaviour

[ET_]

Hi all,

new forum user here :]

I've come across some strange behaviour when using a chateau R16 in what seems to be in specific areas on EE's network.
(Mostly around Cardiff)

Essentially if the network mode is set to LTE & 5G the modem will not connect the mobile network at all (gets denied).
Though if LTE only is enabled it connects fine (obviously without 5G).

I will see if I can add logs with the modem output from when 5G is enabled.

  modem-output-log.txt (Size: 3.4 KB / Downloads: 144)

current firmware:
RG520FEUEAR03A04M4G

   

Using the exact same unit + SIM elsewhere it will connect to LTE+5G no problem...

   

   

   

Curious if anyone can tell what could be going on.


Masts are far apart as I do a lot of travelling for work :)

[Seán]

EE operates 5G band n1 as a DSS band where it shares the spectrum with 4G on the same band. I get the impression the network was trying to get your router off band 1 for 4G access and that you may be outside the maximum distance for it to connect in 5G mode on that band. From my experience with Eir here in Ireland, if a 5G router tries connecting in 4G mode on DSS band 3, the network will detach, which over the maximum distance will cause an endless cycle of it trying to reconnect until either 5G is disabled or 5G band 3 is deselected.

Going by your modem LOG, it tried roaming on band 1 on the Three UK network (Cell ID 11517, EARFCN 1392, PCI 453), which denied access.

In the LTE configuration (General tab), try selecting NR band 78 only. If you get no 5G connection (i.e. not within band n78 coverage), you can try adding the following band numbers one at a time, the other 5G bands EE operates as mentioned on Pedroc: 1, 3, 7, 28. If the router fails to connect, remove that 5G band number and continue with the next.

[ET_]

EE operates 5G band n1 as a DSS band where it shares the spectrum with 4G on the same band.  I get the impression the network was trying to get your router off band 1 for 4G access and that you may be outside the maximum distance for it to connect in 5G mode on that band.  From my experience with Eir here in Ireland, if a 5G router tries connecting in 4G mode on DSS band 3, the network will detach, which over the maximum distance will cause an endless cycle of it trying to reconnect until either 5G is disabled or 5G band 3 is deselected.

Going by your modem LOG, it tried roaming on band 1 on the Three UK network (Cell ID 11517, EARFCN 1392, PCI 453), which denied access. 

In the LTE configuration (General tab), try selecting NR band 78 only.  If you get no 5G connection (i.e. not within band n78 coverage), you can try adding the following band numbers one at a time, the other 5G bands EE operates as mentioned on Pedroc: 1, 3, 7, 28.  If the router fails to connect, remove that 5G band number and continue with the next.

Bang on the money.
It can connect to n3,7,28 and n78 no problem. Just need to make sure n1 is not enabled.

   

Now that it is working, I have been experimenting with 5G SA since EE has deployed it on the serving mast.
Unfortunately seems like my company SIM does not support SA mode. Though I am still able to connect to the SA cells without being registered:

Code:

lte1: rcvd +QENG: "servingcell","LIMSRV","NR5G-SA","FDD",234,30,231608006,883,1C52B,156510,28,1,-65,-10,24,0,58

lte1: rcvd +QENG: "servingcell","LIMSRV","NR5G-SA","TDD",234,30,049188003,817,1C52B,646272,77,6,-89,-12,2,1,38

As per Quectel's docs the perameters are as follows in SA mode:

Code:

+QENG: "servingcell",<state>,"NR5G-SA",<duplex_mode>,<MCC>,<MNC>,<cellID>,<PCID>,<TAC>,<ARFCN>,<band>,<NR_DL_bandwidth>,<RSRP>,<RSRQ>,<SINR>,<scs>,<srxlev>

Link to pdf:
section 5.20
https://forums.quectel.com/uploads/short...aeWLXx.pdf


-ET

[Seán]

With 80MHz of bandwidth between the two 5G band n78 carriers and very good signal strength and SINR readings, I'm surprised the network was trying to switch your band 1 connection over to 5G. I've no doubt this is much faster than had it been able to connect on 5G band n1.

As band 1 is a DSS band, you can leave it disabled as there is generally negligible benefit in connecting to it in 5G mode other than for lower latency or faster upload speed in areas where EE does not operate any other 5G band.

I am curious to see whether SA mode will enable connections over a longer distance as 5G NSA appears to be limited to around 10km to 15km, even on the FDD bands which should not be as sensitive as TDD for upload timing synchronisation. None of the Irish network operators around here operate 5G SA at this time.