• State Verified Answer
  • Replies 4 replies
  • Subscribers 86 subscribers
  • Views 246 views
  • Users 0 members are here
Attachments (0)
Nordic Case Info
  • Case ID: 358399
Options

nRF91 coexistence support - Can LTE radio be gated by an external radio?

droberson

To preface:

  • Board: Custom with nRF9151 module
  • nRF Connect SDK / Toolchain: 3.1.0
  • Modem Firmware 2.0.4
  • Carrier: Verizon and T-Mobile

Hello,

Question: Can the nRF9151 modem LTE radio be gated by direction of an external Packet Traffic Arbiter (PTA) using a 1-wire GPIO solution?

I know the nRF9151 has a "grant" signal by means of COEX2 where it can allow other MCU's to use the airspace where the nRF9151 has priority. From my understanding, using the nRF Connect SDK BLE stack as an example, this requires the BLE stack to be tightly coupled with the grant signal via the MPSL layer. This is demonstrated with the following example:

docs.nordicsemi.com/.../README.html

Can the reverse be done? Ie, can the nRF9151 modem stack be tightly coupled with the MPSL layer that receives a grant from another MCU to allow LTE transmissions? For example, could you could wire a PA (Power Amplifier) signal from a nRF52840 to a gpio on the nRF9151 and configure this GPIO as a LTE grant? In this scenario, the nRF52840 BLE stack would have priority.

Edit: Your new AI tool says this can't be done. Since I know AI can hallucinate, I decided to post this question anyway just to confirm. From my research, I agree with the AI tool, but confirmation would be much appreciated.

Thanks,

Derek

Parents
  • +1

    Hi Derek,

    Can the reverse be done? Ie, can the nRF9151 modem stack be tightly coupled with the MPSL layer that receives a grant from another MCU to allow LTE transmissions? For example, could you could wire a PA (Power Amplifier) signal from a nRF52840 to a gpio on the nRF9151 and configure this GPIO as a LTE grant? In this scenario, the nRF52840 BLE stack would have priority.

    Unfortunately, the AI was right this time, it can't be done the other way around.

    I believe the reason behind this "host-only" solution is that LTE communication require some very strict timing and regulations, so it needs to act as the host.

    Also, if you are OK sharing that (keep in mind that this is a public ticket), can you tell me a bit more about the reason behind that requirement ?

    Best regards,

    Simon D-M    

  • 0 in reply to Simon D-M

    Hey Simon,

    Thanks for confirming, that was my suspicion. The reason I am looking into this is for a project where the host MCU is still running the legacy nRF5 SDK, and not the nRF Connect SDK. To my knowledge, the legacy SDK SoftDevice doesn't have coexistence support. Please correct me if I am wrong.

    Thus, I thought I could be clever and perhaps reverse the logic since the nRF9151 obviously uses the new nRF Connect SDK. Alas, this doesn't seem possible.

    Question: Can you confirm that the legacy nRF5 SDK doesn't have 1-wire coexistence support?

    It looks like I will have to devise a handshaking / grant protocol over our modem communication interface.

    Thanks,

    Derek

  • 0 in reply to droberson

    Hi,

    I don't know nRF5 SDK too much, but I wasn't able to find anything about having COEX on nRF5 SDK.

    I even found another DevZone ticket (324716) where a colleague said that we didn't have it for Wi-Fi. I assume this is the same for cellular COEX.

    Best regards,

    Simon D-M

Reply Children
Related
Terms of service