[Discuss-gnuradio] Dynamic OFDM carrier allocation

[adrian . perez . portero]

Hello,
I am currently implementing a system where a receiver monitors the  
channel, senses the non-allocated OFDM carriers, and transmits through  
the gaps.
I have created a block that lets me estimate those gaps in the  
spectrum, but I have several doubts about how it interacts with the  
rest of the flowgraph:

    1. I want the block to transmit the range of unallocated carriers  
to another part of the flowgraph. I've read about the Probe blocks and  
message passing, but they look overly complicated for the task. Could  
I directly access a GRC variable from my python code and set its value  
to the new range? Or should I use messages / probes?

    2. It depends on the first question, but if I wanted to first  
average the obtained unallocated carriers and then transmit the value,  
how would a block that transmits 1 value every 5 inputs work in this  
situation? I guess messages would make more sense, as I could send the  
message once I am sure of the carrier allocation, and only update the  
variable with meaningful values.

    3. As for the Carrier Allocation block, I've read in  
https://lists.gnu.org/archive/html/discuss-gnuradio/2014-02/msg00416.html that  
it is not possible to update the allocated carriers during execution.  
When implementing a new block capable of doing that, would the  
constant change of the allocation cause problems with the tagged  
stream of constant length that comes before it?