[USRP-users] [RFNoC] Listen Before Talking (LBT)

Michael West michael.west at ettus.com
Fri Oct 13 15:48:57 EDT 2017

Hi Felipe,

That is absolutely possible to do in RFNoC and not very hard.  You simply
create a block that has 2 input ports and 2 output ports with one input
from the DDC, one input from the DMA FIFO, one output for the RX data back
to the host, and one output for data to the DUC.  All of your power
calculation and control logic sits in the block.  User registers can be
instantiated to control the threshold and any other dynamic parameters you


On Tue, Oct 3, 2017 at 1:42 AM, Felipe Augusto Pereira de Figueiredo via
USRP-users <usrp-users at lists.ettus.com> wrote:

> Dear All,
> I'm thinking of implementing LBT with RFNoC, however, after an initial
> study of the RFNoC framework I realized it would be hard to implement
> what I had in mind:
> Initially, I would start with a very basic approach:
> 1) Calculate the power received just after the DDC for every received
> packet
> 2) If the power is greater than a defined threshold I would disable
> the DUC from reading new IQ samples from the dmaFIFO. Disabling DUC
> would require a new output signal (DDC) and input signal (DUC).
> However, I think the approach with input/output signals would not be
> the best one but I don't really have better ideas as I'm quite new to
> RFNoC.
> Now comes the reason why I'm writing this email, I'd like to know if
> there is a better approach for this LBT implementation with RFNoC.
> Any hint will be very helpful!
> Thanks and Kind Regards,
> Felipe Augusto
> _______________________________________________
> USRP-users mailing list
> USRP-users at lists.ettus.com
> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
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