Sara N211, AT+NUESTATS command. Is the Power level parameter the RSSI?

#1

Hi! I have performed some measurements with the SARA-N211 module (on the SARA AFF board) and unfortunately the AT commands manual is not very detailed with the parameters measured by the AT+NUESTATS command. Does anyone know where I could find more info? I am particularly interested in the signal power parameter, which is only explained as Number NB-IoT signal power expressed in tenth of dBm in the manual and also in its relation with total power, described as Total power within receive bandwidth expressed in tenth of dBm.

Is the signal power somehow related to the RSSI?

(Sorry if it’s a stupid question, but I am a beginner)

Thank you

rssi

#2

Yes, RSSI is a measurement of signal strength.
In fact the acronym itself stands for " Received Signal Strength Indicator"

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#3

Also the command AT+CSQ gives you the RSSI directly

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#4

Thanks a lot for the clarification, i wasn’t expecting such a quick reply! For some reason, the AT+CSQ command is giving me trouble. The second parameter(which in my case for LTE is RSRQ) is always 99, even though the RSRQ is also measured with AT+NUESTATS without issues. My only concern is that it doesn’t specify whether “signal power” is received or any other details about it. I was suspecting it is the rssi, but i wasn’t sure, and since it is very implementation specific, i didn’t find a lot of info other than the manual and the datasheet.

Thank you again for your response.

#5

Hello there,

I was perplexed by the same thing a couple of days ago too.

Take a look at pages 28 and 29 of the AT-Commands PDF…

For most of the AT commands there is a special note for the SARA-N2 series, at the end of each ‘listing’

Specifically for the +CSQ command, they state (@ page 29) the following:
“The parameter is not supported, and will be always set to 99”

It also maps the “rssi” parameter that the module returns, to the real RSSI value (in “dBm”)

#6

Oh, that’s true, i didn’t notice that note about it not supporting it. My problem is that I have already performed a lot of measurements, but only with the +NUESTATS command, and I do not have acces to redo them. I was interested in a mapping between the “signal power” that is returned by +NUESTATS and the RSSI returned by +CSQ and I can’t seem to find that anywhere. Do you know anything about this?

Thank you

#7

I think you can use the “RADIO” parameter of the +NUESTATS command,
it seems to return the power level…

NUESTATS: “RADIO”,“Total_power”

• : NB-IoT signal power expressed in tenth of dBm

(page 23 and 24)

#8

Yes, that is what i was using. At page 25, in the table with the parameters of +NUESTATS, there are 3 power parameters:

image.png750×102 9.65 KB

I am not sure which one of these is the RSSI and how they relate to each other and to the RSSI returned by +CSQ :sweat:

#9

As far as I can understand it you should use the “power” parameter and that will give you
a value in dBm (or dBm /10), so then you can map it to the CSQ value using the table in page 29.

We can also wait for an “official” answer on that from someone at SODAQ.

If you don’t mind me asking, how are you getting the +NUESTATS power value and storing it?
Are you doing it with AT commands or are you using a library, and how?
Also, what board are you using? THe shield, the module or the arduino board?

#10

I am using this board https://shop.sodaq.com/sodaq-sara-aff.html

I programmed it to receive on the serial interface, with arduino with the use of the Sodaq_nbIOT.h library. And then I am sending the AT commands with a terminal called QCOM which allows to store in a txt file what it receives on the usb interface. Afterwards I am extracting the values from the txt in python with regex. I don’t know if this is the best or easiest way to do it.

#11

Thanks for the reply.
I am trying to do a similar thing, only on a handheld device.
What command from the Sodaq_nbIOT.h library are you using to store
values from the +NUESTATS AT command?

Also, if you have your values in a txt file on a PC, could you import it into an excel file
and then map it on to whatever values you want? I don’t know your final project goals,
so I am just guessing.

#12

I uploaded this code to the board https://github.com/SodaqMoja/Sodaq_nbIOT. Afterwards, i didn’t send the commands on the serial terminal from arduino, but instead i used QCOM, which allows to store the response you get from the AT commands. This is how the terminal looks like.

qcom_ex1.png990×787 36.1 KB

Unfortunately you can’t import it directly to excel, as the txt doesn’t just contain the values, they are in the form of the response given from +NUESTATS, as it shows in the manual: