EMRFD Message Archive 3574
Message Date From Subject 3574 2009-09-26 21:30:30 Ashhar Farhan Cognitive Radio. What is it?
From the Wikipedia entry, I gather that it is a software that drives
the radio to choose bands and frequencies that are interference free
but it is skimpy on the details.
thanks in advance.
- farhan3575 2009-09-26 21:32:24 Ashhar Farhan Cognitive Radio. What is it?
From the Wikipedia entry, I gather that it is a software that drives
the radio to choose bands and frequencies that are interference free
but it is skimpy on the details.
thanks in advance.
- farhan3577 2009-09-27 03:05:04 Niels A. Moseley Re: Cognitive Radio. What is it?
the (changing) requirements of its user and its (RF) surroundings.
In practice, the cognitive radio research community focusses on scanning
the radio spectrum to find empty/unused spots (termed 'white spots') to
setup a dynamic ad-hoc network. This way, the operator is not required
to license an (expensive) chunk of spectrum, like it is done now for
UMTS or DVB etc.
There are many problems with this kind of networking. For instance, how
can the operator establish that a part of the frequency spectrum is
indeed white.
Consider a TV transmitter and a receiver located at the very edge of the
TV transmitter's service area. The DSA (dynamic spectrum access)
operator is futher way still, so that the TV signal is below the noise
floor of the DSA receiver. Now, if the DSA operator identifies this
spectrum as white and starts transmitting, the increased interference at
the TV receiver's location might cause bad reception of the TV signal.
While the concept seems nice on paper (especially to the money people)
in practice it's value is limited.
The FCC is working on the legislative aspects of such systems
(http://www.fcc.gov/oet/cognitiveradio/).
There are several conferences on the subject. The most notable is IEEE
DySPAN: http://www.ieee-dyspan.org/
Some related buzzwords are: Software radio, Software-defined radio,
Agile radio, Intelligent radio, Dynamic spectrum access, Ad-hoc
networking, Opportunistic spectrum usage and Spectrum harvesting.
73,
Niels PA1DSP.
> Can someone enlighten me about what exactly is cognitive radio?
>
>>From the Wikipedia entry, I gather that it is a software that drives
> the radio to choose bands and frequencies that are interference free
> but it is skimpy on the details.
>
> thanks in advance.
>
> - farhan
>
>
> ------------------------------------
>
> Yahoo! Groups Links
>
>
>
>3578 2009-09-27 07:15:07 Ashhar Farhan Re: Cognitive Radio. What is it?
thank for the detailed reply. i get a feeling that this is more of a
marketing speak rather than a definite technology.
- farhan
3579 2009-09-27 08:24:54 leon Heller Re: Cognitive Radio. What is it?
3580 2009-09-27 09:38:05 w4zcb Re: Cognitive Radio. What is it?
> marketing speak rather than a definite technology.
military applications like battlefield comms in conjuction with
frequency
hopping, to avoid jamming by the enemy.
Leon
Another "feature" I would expect to fall under this category is
automatic power level control. Where the receiving station adjusts the
transmitting stations power level to that required for communications.
I'm told cell phone operation is controlled in this manner, not at all
sure as to how well it's going to be received by the parallel 4-1000,
7KV amplifier guys.
W4ZCB3582 2009-09-28 04:19:11 john_hague1963 Re: Cognitive Radio. What is it?