Product range extension with nRF21540

[Andrea]

Hi there,

We have developed a family of BLE products based on the NRF52832 using it's maximum TX power 4dBm.

We have a strong push for increasing the communication range of the next generation devices and I was looking at the nRF21540 FEM. I have few questions and I tough to put all of them down in a single post:

1) Assuming we make new products with the nrf52832+FEM combo, will it improve range communication even in the asymmetrical case (old device talking with a new one)?

2) These products are battery powered, is there a way to measure current consumption impact of using the FEM? It seems cannot be included in the Online Power Profiler, will be nice to have an idea of the average current consumption addition once the FEM is enabled or have a formula to calculate it (how many uC @3V x Adv event @ given TX power).

3) Our SW development is based on the NRF SDK, I have seen the FEM is supported on the latest NRF SDK 17. Is there any drawback compared to using the nRF Connect SDK regarding the FEM management? Any feature we are missing not using the NCS?

5) In case we plan to use two antennas, is antenna diversity automatically managed by the driver? or should we switch between antennas at the application level?

6) Considering that for main of our application the TX power will be limited to 10dBm due to regulatory reason (deployed manly in EMEA and US), the other option would be to use the nRF52833 @ TX8dBm/RX95dBm. Is there any comparison or estimation on range compared with a nRf52832 + FEM @ TX10dBm/RX100dBm solution. 

Thanks for your help,

Andrea

[Hieu]

Hi Andrea,

1) Assuming we make new products with the nrf52832+FEM combo, will it improve range communication even in the asymmetrical case (old device talking with a new one)?

I need to double check a couple of things on this. I will get back to you tomorrow.

2) These products are battery powered, is there a way to measure current consumption impact of using the FEM? It seems cannot be included in the Online Power Profiler, will be nice to have an idea of the average current consumption addition once the FEM is enabled or have a formula to calculate it (how many uC @3V x Adv event @ given TX power).

If you want a rough estimation, you can refer to the Current Consumption section of the Product Specification.

If you want to measure it experimentally, you can measure the current consumed by a nRF21540 using the nRF21540 EK with this guide.

While working on this topic, please also be aware of the Errata, some of which have an impact on the current consumption.

3) Our SW development is based on the NRF SDK, I have seen the FEM is supported on the latest NRF SDK 17. Is there any drawback compared to using the nRF Connect SDK regarding the FEM management? Any feature we are missing not using the NCS?

Unfortunately, the FEM is not fully supported in nRF5 SDK v17.1.0.

5) In case we plan to use two antennas, is antenna diversity automatically managed by the driver? or should we switch between antennas at the application level?

Automatic antenna diversity is not available. You will need to switch between antennas in your application.

6) Considering that for main of our application the TX power will be limited to 10dBm due to regulatory reason (deployed manly in EMEA and US), the other option would be to use the nRF52833 @ TX8dBm/RX95dBm. Is there any comparison or estimation on range compared with a nRf52832 + FEM @ TX10dBm/RX100dBm solution. 

We don't have a test data for the nRF21540 at 10 dBm TX and 100 dBm RX. If such data is critical for your decision making, could you please have a word with your Nordic Semi Regional Sales Manager? For Italy, you can contact Regional Sales Director Rober Pedersen at [email protected].

And I will get back to you with your question #1. Please feel free to ask any questions you may have though.

Best regards,

Hieu

[Andrea]

Thanks Hieu for all the precious details!

While waiting for question #1 may I ask what are the limitations if we use SDK17 with the FEM?

What are we losing in terms of performances?

Thanks for your help,

Andrea

[Hieu]

Hi Andrea,

1) Assuming we make new products with the nrf52832+FEM combo, will it improve range communication even in the asymmetrical case (old device talking with a new one)?

The range should be increased even for asymmetrical case, assuming that means a nRF52/53+FEM talking with a nRF52/53.

Andrea said:

While waiting for question #1 may I ask what are the limitations if we use SDK17 with the FEM?

What are we losing in terms of performances?

It is simply that the SDK does not support integration with the nRF21540 much. There are some drivers being setup, but that is it.

If you choose to implement your own support for the nRF21540, we are not sure we can provide support.

Reference:  RE: Nrf52840 DK interface with Nrf21540 EK using Nrf5 SDK 
RE: nRF5 SDK with nRF21540 DK 

Hieu