If there are a number of ways, then please describe the best possible way solve this problem."First of all, what you're describing is barely cognitive; you want to look at the momentaneous power in a subchannel, and transmit only when it's free. That principle is simply known as Carrier Sense Collision Avoidance, and present in a lot non-cognitive communication methods.
Cognitivity requires that you can use your channel observations to build a model of channel usage, and if possible, employ that to schedule your transmissions. Ankit Kaushik from KIT as some work on reinforcement learning strategies for that.
Now, you already have a pretty usable description of your system:
Basically I need to link the output from the threshold block from the energy detector flow graph with that of the USRP source such that the USRP transmits at a frequency where the threshold block outputs a zero value.Well, you will need to write a block that takes the output of your energy detection and produces a sample stream based on that, which might be 0 as long as you're not transmitting, and nonzero if you're using the channel.
You said you've read the tutorials – these cover writing blocks, and so I think it'd be helpful if you did some experimentation on your own and then discuss the questions that arose from that!
Best regards,
Marcus
On 02.04.2016 15:25, Prabaha Biswas
wrote:
This is our conversation from last month:
"I am trying to design a cognitive radio. I have already designed an energy detector as part of spectrum sensing and now I am trying to implement spectrum management. So, I need to transmit a signal at those sections of the frequency spectrum where the threshold block outputs a zero value. Basically I need to link the output from the threshold block from the energy detector flow graph with that of the USRP source such that the USRP transmits at a frequency where the threshold block outputs a zero value. Is there a way to do this ?"
The above is the question that I asked to which you replied as follows:
"Yes, there are ways to do this, but you'll have to come up with some approach of an application you want to do that way.
You say you've implemented an energy detector, so I guess you're already familiar with the Guided Tutorials[1]?"
After this I replied:
"Yes, I am familiar with the guided tutorials. I don’t understand what you meant when you said that I’ll have to come up with some approach of application from my side.
If there are a number of ways, then please describe the best possible way solve this problem."
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