10 months, 3 weeks ago.

Nanostack WiSUN border router example only using even numbered channels

I am exploring the WiSUN example in the nanostack-border-router and notice that the border router only sends packets on even numbered channels.

The default configuration assigns regulatory domain EU, op class 2, and op mode 3. WiSUN PHY specification indicates this has a 200kHz channel spacing.

A connecting node which specifies a Unicast schedule with fixed channel other than 0 results in the border router sending unicast messages to that node on (channel x 2) instead of channel.

This appears to be a bug in setting the radio channel but I haven't figured out where it's going wrong. The radio driver for this example only has support for the S2LP radio which I am using.

Looking at the NanostackRfPhys2lp.cpp I see something about the channel_spacing_registers but I don't yet understand or can confirm if the spacing is correct. Any guidance on where to look or how to check this?

Separately is it possible to configure the example to use a custom channel plan with channel 0 center frequency, channel spacing, and number of channels?

I was able to confirm the radio is tuning to twice the channel spacing. I added sniffers for what would be even numbered channels beyond the supported range for and do see the PAN Advertisement and Configuration messages on those channels too.

I tried changing region to KR, opclass 2, op-mode 3 and the same thing is happening here.

posted by James Ko 23 Sep 2019

1 Answer

9 months, 2 weeks ago.

Hi James,

I think this bug was fixed on the Mbed OS 5.14.1 patch release https://os.mbed.com/mbed-os/releases/ - "Bug fix related to channel spacing configuration".

The configuration is currently limited to https://github.com/ARMmbed/mbed-os/blob/mbed-os-5.14.1/features/nanostack/mbed-mesh-api/mbed_lib.json#L117-L120 and unfortunately there is yet no support for custom channel plan. I've also created internal ticket to improve the mbed_lib.json documentation to add definitions to available regulatory domains.

Best regards,

Jaakko, team Mbed.