RE: Optimizing LTE Connectivity on nRF9160 DK: Band Selection, Antenna Considerations, and Tower Switching

Michal — Fri, 24 Nov 2023 15:34:24 GMT

Hello,

I am coming back with some answers from the experts:

[quote user=""]I do understand that the size of antenna limits the antenna's bandwidth and this may affect also affect performance, link. Does this mean that certain LTE antennas can only work properly on certain bands?[/quote]

There’s various types of cellular antennas with different band support and other constraints / performance spec. Also how antennas behave in different kind of environments (in vicinity of metal or human tissue etc.) depends on antenna type and spec. and actual implementation of product.

So, definitely yes; antenna is defined to support certain set of LTE bands and it should be considered in antenna selection.

Recommended related reading can be found from Nordic webpage.

[quote user=""]According to this post, it is possible to switch to a different tower. I use the +COPS command, and the picture below shows how I done it. Is there any other way to choose the tower. I would like to specify the CID instead of mcc and mnc because I get many towers with the same mcc and mnc.[/quote]

+CEREG=4 is reported typically when there are no suitable cells available. Have other bands than B20 been deployed at the customer’s location? To be also noticed, that it depends on roaming agreements on which networks the device is allowed to Attach with the SIM card.

There is no way to choose the tower. With +COPS you can force modem to select certain network, but that doesn’t affect to selected tracking area, cell ID, etc.

About the cell selection (referred to as "band selection"). It is true that the modem stores a history of the cells and networks for being able to fast camp on a cell again later. And, of course, it is possible that the signal to a historical cell is not as good anymore than what it was earlier. Still, the modem will not try to camp on a cell that doesn't fulfill normal suitability criteria defined by 3GPP. If the mentioned criteria are fulfilled, the modem will camp on the cell but after that, the modem counts on the cell reselection criteria for which also the network has saying via the mentioned offsets. To be noted that the strongest cell may not always be the best from networks perspective; network deployment could be such that they want to steer devices in a certain direction.

Best regards,

Michal

RE: Optimizing LTE Connectivity on nRF9160 DK: Band Selection, Antenna Considerations, and Tower Switching

Michal — Wed, 22 Nov 2023 09:06:40 GMT

Sorry for the delay, I have asked the experts to help me with answering those questions.

Best regards,

Michal

RE: Optimizing LTE Connectivity on nRF9160 DK: Band Selection, Antenna Considerations, and Tower Switching

Michal — Mon, 13 Nov 2023 14:33:24 GMT

Thank you for understanding.

I will get back to you when I will have more information.

Best regards,

Michal

RE: Optimizing LTE Connectivity on nRF9160 DK: Band Selection, Antenna Considerations, and Tower Switching

J0sh1101 — Sun, 12 Nov 2023 16:25:43 GMT

Hello,

I understand. I have asked a lot of difficult questions and thank you for the response.

RE: Optimizing LTE Connectivity on nRF9160 DK: Band Selection, Antenna Considerations, and Tower Switching

Michal — Fri, 10 Nov 2023 15:17:29 GMT

Hello,

Just wanted to let you know that it will take me some time to investigate all your questions and I will come back to you during the next week.

Best regards,

Michal