Different multicell location with different SIM

[artsem artsemenka]

Hi Nordic team,

I’m testing neighbor cell measurements with 9160DK and see completely different results with 2 SIM cards:

• Google Fi SIM (T-mobile): 1 neighbor in most cases, sometimes 2, very rare 3 or 0.
• Hologram SIM (AT&T): 0 neighbors in most cases.

Can you please explain:

1. Does neighbor cell measurements depend on SIM?
2. How to force the modem to get all neighboring cells available with any SIM?

I suspect that the issue may be similar to one described here, can you please confirm this:
devzone.nordicsemi.com/.../329996

If it is the same issue, is it possible to fix it with modem FW to force it to get more cells by spending more time/energy?
Do you have plans to implement this?

Please see the attached modem traces for both SIM cards:

Fi(T-mobile):

/cfs-file/__key/communityserver-discussions-components-files/4/6685.fi_5F00_t_5F00_mobile_5F00_sim.bin

/cfs-file/__key/communityserver-discussions-components-files/4/7356.fi_5F00_t_5F00_mobile_5F00_sim.pcapng

Hologram (At&T):

/cfs-file/__key/communityserver-discussions-components-files/4/3146.hologram_5F00_sim.bin

/cfs-file/__key/communityserver-discussions-components-files/4/5265.hologram_5F00_sim.pcapng

My setup:

Board: 9160DK v1.1.0
Modem HW: B1
Modem FW: 1.3.2
nRF Connect SW: 3.12.0
nRF Connect SDK v2.0.99

App: multicell_location_sample:
Sends AT%NCELLMEAS with search type 2 only,
Measurements every 20 seconds,
No cloud requests to save data and time.

Location: 37.78074224974799, -122.3969109527513 ( San Francisco, urban area ).

Thank you!
Artsem Artsemenka.

[Håkon Alseth]

Hi,

 

When registered to T-mobile, you detect neighboring cells, and have up-to SIB5 present, on LTE bands 12 and 4.

For your connection towards AT&T, you have SIB2/3/4, and no reported neighboring cells other than the one you're currently connected to on band 12. You have a very strong connection to this cell, and you don't pick up any neighboring cells.

Neighboring cells has some requirements both wrt. the network you're connected to, and the surrounding PCI's:

https://developer.nordicsemi.com/nRF_Connect_SDK/doc/2.0.2/nrf/samples/nrf9160/multicell_location/README.html#cell-measurements

 

Kind regards,

Håkon

[artsem artsemenka]

Hi Håkon,

Thanks for the quick response.

For tracking applications getting multiple cells information is critical, even if it takes more energy and time.

Could you please clarify:

1. Can current modem HW scan all bands and get all visible cells regardless of the currently connected cell/band?

2. If yes, do you have plans to implement this in FW?

Arstem.

[Håkon Alseth]

Hi,

 

artsem artsemenka said:

For tracking applications getting multiple cells information is critical, even if it takes more energy and time.

Could you please clarify:

1. Can current modem HW scan all bands and get all visible cells regardless of the currently connected cell/band?

2. If yes, do you have plans to implement this in FW?

For inter-frequency neighboring cells (ie. cells on a different frequency), these are broadcasted via the SIB5 (System information block) from the network. If SIB5 is not present, NCELLMEAS will not report neighboring cells on other bands.

 

As you saw in the T-mobile trace, there are reported cells on a different band, so the modem supports it if the network provides this information.

 

Kind regards,

Håkon