WANT TO FIND LQI (Link Quality Indicator)

[fenil.patel]

Hello,

            I am developing a sensor like a beacon. I want to measure the distance from the node. I record the RSSI sample for a few seconds and average it to stabilize the value. RSSI is not so accurate because rf wave is attenuate or reflected from any object in surrounding and I read the research paper and they use LQI to improve the RSSI accuracy. I also apply some filters to smooth the RSSI but something due to large fluctuation in RSSI I don't get accuracy.

I read the nordic infocenter documentation about LQI in 2.4GHz Radio module but don't get a way to access it.

https://infocenter.nordicsemi.com/index.jsp?topic=%2Fps_nrf52840%2Fradio.html

Can anyone help to find it out?

Thank you.

[Jared]

Hi,

 

I read the nordic infocenter documentation about LQI in 2.4GHz Radio module but don't get a way to access it.

 Unfortunately, The Link quality indicator is only relevant for Zigbee/Thread and not for BLE. 

regards

Jared

[fenil.patel]

Hi Jared,

 Thank you for your effort. I know the LQI is not for distance measurement but i can use it for error correction in distance measurement with RSSI. I am using softdevice s132 and sdk15.2 . Is there any way to get the LQI in ble ? 

[Jared]

no the Softdevice API doesn't expose this feature.

[fenil.patel]

In this diagram, there is  LQI bit but there's no register for getting it. so how the Zigbee/Thread get the LQI?

[Jared]

Hi,

Getting the LQI from the Radio while using the Softdevice is not possible as it's not part of the Softdevice API. The Softdevice doesn't allow the application to access the Radio or its resources unless you're using radio timeslots. 

fenil.patel said:

so how the Zigbee/Thread get the LQI?

 You can find the sourcecode of the OpenThread here. 

regards

Jared

[fenil.patel]

Thank you Jared,

 Now i understand that for LQI i have to use IEEE 802.15.4 protocol in nrf52832. There is EDSAMPLE register to get LQI and it only accessible in IEEE 802.15.4 protocol. I think in BLE protocol in nrf52832 I can't get LQI.