AT86RF215: How to increase increase TX power on OpenMote-b

[JohaYuuki]

Hello, I am working with OpenMote-b modules with the at86rf215 chip, in mr-fsk modulation according to the IEEE 802.15.4 standard. I have been trying to change the Tx power to use it at 14 dBm, in the MakeFile I have used the statement

CFLAGS + = -DCONFIG_IEEE802154_DEFAULT_TXPOWER = 14

however the TX power does not increase by 3dBm. I attach the Makefile that I use
Makefile.txt

[benpicco]

Yea the dBm value displayed by RIOT is bogus. Since the TX power depends on the chosen modulation and frequency (see AT86RF215 data sheet, chapter 11.1 "Output Power at Several Modulations") we would need to maintain several tables in ROM just to display the right value.

Instead, dBm displayed is just TXPWR - 31 dBm. (It would of course be possible to implement it so that the proper calculation could be enabled with a compile-time option if desired - patches welcome!)

The added 3 dBm are then achieved by the 3 possible states of the PACUR value, which sets the operating current of the power amplifier. (Each step adds ~1dBm so this is not that far off).

That means that +3 dBm in RIOT are equal to PACUR = 3 and TXPWR = 31 which is the highest possible output power (which should yield +14 dBm with (MR)-O-QPSK)

[JohaYuuki]

I understand.
We performed tests with OpenMote devices at various distances with the different modulations allowed, but we could not reach 200 meters. Even with modulation (MR) -O-QPSK.

[benpicco]

Huh that's odd - did you have the right antennas attached? On the sub-GHz band you should be able to get 500m with the low bit rate MR-O-QPSK modulations.

[JohaYuuki]

Hello, I've been trying to reach 14 dBm, however as you said I think it's bogus because I haven't managed to reach more than 100 meters. Do you know where the registry or file is located where the power is increased?

[benpicco]

The register is written here.
Which frequency and modulation did you use?
What antennas are connected to the OpenMote-B?

[JohaYuuki]

I use MR-FSK with 863.125 GHz as the center frequency.
With SubGhz antennas on the SubGhz interface

[benpicco]

Hm can you try with MR-O-QPSK, this generally has the best performance on this chip.
Select rate mode 0, 100k Chip/s with

ifconfig 6 set phy mr-o-qpsk
ifconfig 6 set chips 100
ifconfig 6 set rate_mode 0

if you are using an interactive shell (and change the interface ID if necessary)

[JohaYuuki]

Hello again,
I have been working with the same OpenMote B module, configuring a Fan Mesh network with a border router(gnrc_border_router) and two sensor nodes(emcute_mqttsn). I have a problem when trying to connect the border router and the tap interface with ethos, many packets are lost between the ethernet interface and the tap interface. That is, when trying to connect from the border router to the tap and vice versa. Would you know why it happens or something would be configuring wrong?

[benpicco]

I think some more information is needed. How much data is being sent and in which intervals?
Do you see the data in Wireshark? And what is sending to what?

If you need more performance, try a higher UART baudrate and switch to SLIP instead of ethos (UPLINK=slip with the border router example).

Also I think a forum post would get you some more exposure with your issue.

[JohaYuuki]

First I send a ping between the ethernet interface and tap interface and some of the packets are lost

Then I Send some data on UDP protocolo and some packets are lost or malformed. The data is sent in a intervals of approximately 15 seconds.

If I use 3.0 ports for the connection of the Open Mote B module, could it be the causeof the losing?