Hi Biswas, > 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." > <https://sigads.rediff.com/RealMedia/ads/click_nx.ads/www.rediffmail.com/signatureline.htm@Middle?> > > Get your own *FREE* website, *FREE* domain & *FREE* mobile app with > Company email. > *Know More >* > <http://track.rediff.com/click?url=___http://businessemail.rediff.com?sc_cid=sign-1-10-13___&cmp=host&lnk=sign-1-10-13&nsrv1=host> > > > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
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