nRF9160 Obtain used TX-Power

[BjoernS]

Hello everyone,

I have one or two questions regarding some evaluation measurements on the nrf9160 module.

I would like to evaluate the matching network of our nrf9160 antenna connection by using a network and spectrum analyser. First I was trying to use the udp example to try to evaluate the network but since I am connecting the spectrum analyzer directly onto the antenna socket the modem is obviously not able to establish a network connection;thus sending no udp packets. Am I right, that I can use the AT%XRFTEST command overcome this problem for this evaluation purposes? I am aware, that I am dealing with licenced bands here, so I will do these measurements in shielded environments only.

Furthermore and more importantly, during current consumption measurements of the nrf9160 while sending/receiving data I noticed that the current consumption of the module varies (and thus output power of the modem) depending on the signal quality. Is there a command or C function to read the TX Power that the modem used to transmit the last data packet? This would be of major interest for me/us. I know that it is not possible to change the TX power of the module since it is negotiated between Cell and Modem but I would like to know the used TX power by the modem.

Kinds Regards,
Bjoern

[Håkon Alseth]

Hi,

 

You are correct in your assumption. The TX power is dynamic, based on the link quality (controlled by the eNB). 

Am I right, that I can use the AT%XRFTEST command overcome this problem for this evaluation purposes? I am aware, that I am dealing with licenced bands here, so I will do these measurements in shielded environments only.

This is correct. You should use AT%XRFTEST to test the RF PHY reliably. Its good to hear that you have already thought about the implications of testing in licensed bands.

 

Furthermore and more importantly, during current consumption measurements of the nrf9160 while sending/receiving data I noticed that the current consumption of the module varies (and thus output power of the modem) depending on the signal quality. Is there a command or C function to read the TX Power that the modem used to transmit the last data packet? This would be of major interest for me/us. I know that it is not possible to change the TX power of the module since it is negotiated between Cell and Modem but I would like to know the used TX power by the modem.

As mentioned, the TX power output from the UE (nrf9160) is controlled by the eNB, based on the link quality. We do not currently have an API to fetch the dynamic tx power, unfortunately.

 

Kind regards,

Håkon 

[BjoernS]

Hi Håkon,

thank you for the reply. 

Håkon Alseth said:

As mentioned, the TX power output from the UE (nrf9160) is controlled by the eNB, based on the link quality. We do not currently have an API to fetch the dynamic tx power, unfortunately.

This is indeed unfortunate. May I ask if there is a plan to implement this feature to your modem API in the near future?

Regards,

Bjoern

[Håkon Alseth]

Hi Bjoern,

 

Unfortunately, I do not have the overview of future features and roadmap related items.

If you contact your local regional sales manager (RSM for short), they can help you answer those sort of questions.

 

If you do not have the contact details of your RSM, please send me a direct message with your location, and I'll give you the contact details to your RSM.

 

Kind regards,

Håkon