Misidentification of B66

[Beat-YT]

So now after the update netmonster misidentify B66 as B3

[Beat-YT]

@mroczis please check this

[mroczis]

This is common issue with Samsung modems. From the screenshot I'm assuming you are using Pixel 7 (Pro) device. Considering the correct EARFCN is 66811 and NetMonster Core returns 1275 we know that there's buffer overflow somewhere in Samsung's native code (the difference is 2^16 = 65536).

The question is how devs of the other app know that it's overflow and 65536 should be added. Please send a bug report from NetMonster app in order to examine raw data from the system.

In order to do it, go to app's settings, fast tap 5 times on Version and then follow instructions.

[Beat-YT]

This issue is affecting my OnePlus 8 5G as well as my Pixel 7. I will you the send bug report from my OnePlus phone since I don't have the pixel right now.

[Beat-YT]

@mroczis here is the report file: report.txt

[eladts]

The question is how devs of the other app know that it's overflow and 65536 should be added.

The solution other apps are using is based on the fact that B3 is never used in North America. If the MCC indicates a country in North America and the EARFCN indicates B3 (or any other band that isn't used in North America such as B1, B8, B20 and B28) just assume the EARFCN has overflowed and add 65536.

[Beat-YT]

The question is how devs of the other app know that it's overflow and 65536 should be added.

The solution other apps are using is based on the fact that B3 is never used in North America. If the MCC indicates a country in North America and the EARFCN indicates B3 (or any other band that isn't used in North America such as B1, B8, B20 and B28) just assume the EARFCN has overflowed and add 65536.

Is this going to be implemented to netmonster / netmonster-core?

@mroczis

[mroczis]

Did some digging and here are the results. Overlapping occurs from band 66+. When it comes to current deployment of LTE networks, there might be following conflicts:

Band	EARFCN	Reported ARFCN	Overlaps with	Where
B66	66_436..67_335	900..1_799	B2, B3	Canada, Chile, Taiwan (B3), USA (B2)
B67	67_336..67_535	1_800..1_999	B3, B4	Switzerland (B3)
B71	68_586..68_935	3_050..3_399	B7	Canada, USA
B75	69_466..70_315	3_930..4_779	B9, B10, B11	Switzerland

Some rules can be hardcoded to NetMonster Core. However there are some limitations:

• B66 + USA - thanks to overlap with B2 only range 1_200..1_799 can be used,
• B66 + Taiwan - thanks to overlap with B3 only range 900..1_199 can be used,
• B67 + Switzerland - thanks to overlap with B3 only range 1_950..1_999 can be used.

Considering that Bell runs B66 on 65_536 + 1275 = 66_811 we are safe in Canada and even for this EARFCN in the US.

Before I add this to Core, don't you know on which EARFCN do conflicting US, Swiss or Taiwanese networks run?

EDIT:

• T-Mobile US seems to also use 66_811 (https://www.reddit.com/r/tmobile/comments/89wftc/band_3_what/)
• Verizon / T-Mobile seems to use 66 486 66 736 (https://www.reddit.com/r/tmobile/comments/u2u7qv/found_new_nsa_ca_bands_configuration/, https://www.reddit.com/r/USMobile/comments/wdxyat/im_out/)
• More EARFCNs https://www.howardforums.com/showthread.php/1901979-Band-66-AWS-3-Deployment
• Complete US https://specmap.sequence-omega.net Seems like US spectrum is divided by each country so making an universal rule is not really possible.

[Beat-YT]

Canada uses pretty much the same bands as USA.

Meaning that we also have band 71 and b2

[Beat-YT]

Beware, Canada Have band 7 however. We also have b41. @mroczis

[Beat-YT]

I also got a screenshot if b66 misidentification on Verizon (roaming)

[Beat-YT]

in my first screenshot, the band 2 screenshot was correct. The only incorrect value was band 3.

Also Canada have band 7 so I you might want to modify the code

[Beat-YT]

Take a look at this

https://issuetracker.google.com/issues/37136986?pli=1

[Beat-YT]

A little poke here, @mroczis

[Beat-YT]

[Beat-YT]

Band 7 is now being identified as B71!!! Canada HAVE band 7

[Beat-YT]

Hello @mroczis

Could you take this in accordance?

[PurveshPatel05]

Hi even I'm having the same issue for freedom mobile Canada the app misidentifying b7 as b71 even though freedom has b71 but it hasn't been rolled out yet and my phone doesn't even support lte b71 and other apps show b7 and even the API from phone states b7 Here is the cell tower and as u can see same

[Beat-YT]

Yes, very blind move from the ghost @mroczis

[Beat-YT]

Hello @mroczis . I also wanted to bring this to your attention:

[mroczis]

Thanks, neighbouring cells were also fixed