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Topic Title: Cognitive Radio Networks
Topic Summary: Cognitive radio access could make incredible efficiancy savings in the spectrum but they could also make a mess.
Created On: 26 February 2011 03:04 PM
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 26 February 2011 03:04 PM
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Avatar for CharlesJEdwards                                   .
CharlesJEdwards

Posts: 6
Joined: 25 July 2008

An OFCOM consultation Digital dividend:cognitive access OFCOM consultation, IET submission spells out some of the benefits and some possible pitfalls of using White Space technologies.

This would open up access to unused (or seldom used) spectrum for many many devices, all hungry for bandwidth.
While steps are being taken to control such devices, you will end up with interference from devices transmitting simultaneously etc.

How wise is it to be opening up the spectrum in such an (uncontrolled?) way?
 01 March 2011 05:01 AM
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backinuk

Posts: 24
Joined: 29 May 2008

Plasma TV, computer power supplies, and PLT's must all be under this Ofcom initative
From what I can gather all of these products are failing EMC regulations badly.
All affect radio communications.
Again my understanding is that if this is allowed to continue that this will start to affect the emergency services too (if it doesnt already)
and also the digital spectrum.
Until a few years down the line we have so much noise that any new RF designs will have to filter out all this noise just to be able to function
It just seems like madness..........
 12 March 2011 03:47 PM
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Avatar for CharlesJEdwards                                   .
CharlesJEdwards

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While looking through a mountain of ETSI and ITU documentation and reports on RRS (Reconfigurable Radio Systems), it seems careful consideration is being given to the threat of interference.
The truth is that bandwidth is precious and there is a huge amount of it that is under utilised.

I believe that by using sensing as well as location based information would allow this concept to prove its value. If a device needs to transmit, it will firstly use location information to find available channels in its area then it will use sensing to prove that the channel is not in use.

It would be surprising for this concept not to be rolled out, for me it is a question of when. The information I've seen suggests the implementation of CRN are a number of years off, although a White Space trial is being run in the States.

Any comment on the possible implementation and any associated obstacles would be great.
 14 March 2011 01:14 PM
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ectophile

Posts: 528
Joined: 17 September 2001

Originally posted by: CharlesJEdwards

I believe that by using sensing as well as location based information would allow this concept to prove its value. If a device needs to transmit, it will firstly use location information to find available channels in its area then it will use sensing to prove that the channel is not in use.


This seems to require that a cognitive radio needs a built-in GPS and up-to-date database of reserved frequencies for each area. What happens if the device cannot get a location fix (because it's inside a building)?

To avoid interference with any other equipment, the cognitive radio needs a receiver that is at least as sensitive as the equipment it may be interfering with. If it doesn't, it will start interering with signals it can't detect. This isn't going to come cheap.

-------------------------
S P Barker BSc PhD MIET
 25 March 2011 05:30 PM
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moinmeer

Posts: 1
Joined: 25 March 2011

Hi Everyone,

I'm a new student in the field of Communication Engineering and just came to know about this new technology Cognitive Radio. It would be great if it is going to be happened. I would appreciate if someone can give me a link where I can get a basic knowledge of sensing techniques and interference cancellation for a Cognitive Radio Network.
And one more thing, if I want to try something regarding these topics, which software is the best to implement the mathematics of Cognitive Radio Sensing and Interference Cancellation?

Kind Regards,
Moin Ilyas.
 30 March 2011 12:30 AM
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backinuk

Posts: 24
Joined: 29 May 2008

Hi
Charles,
4G is this the mobile congnitive network? definately self thinking if my understanding of the optimisation platforms is correct
An article from the "Epoch Times"
http://www.theepochtimes.com/n...way-system-52791.html

"STOCKHOLM - The new, lightening-fast, 4G mobile network is causing problems for Sweden's railways, with more countries likely to be affected.
Sweden has pumped some $2 billion into its mammoth Botniabanan project, a ultra-modern, high-speed railway system that runs through the northern part of the country, supplying a long-awaited service to the people in that area.
The track, which has taken 11 years to build, was opened by the Swedish King Carl XVI Gustaf last year, and is the biggest railroad project in Sweden since 1937.

Although the trains are running at optimum speeds and efficiency, as expected, they seem to have run into an unexpected snag of sorts: the 4G mobile network. That is, vital train signals are getting seriously fouled up.
Here's how these train signals work, or in this case, how they don't work:
The track itself is equipped with a brand new signal system called the European Rail Traffic Management System, or ERTMS, which eliminates the need for traditional, visual light signals by sending signal information directly to the train operator.
But since this part of the train's system is highly sensitive to the mobile 4G network, the emergency brakes, on occasion, suddenly kick in. And that is exactly what happened during 62 out of 140 train departures in October, according to Swedish magazine, Ny Teknik.
Since Sweden is a world leader in mobile Internet traffic, towers upon towers of new, 4G networks are quickly crisscrossing the country.
However, these powerful 4G signals are disrupting the ERTMS, which can lead to problems when the train passes near base stations.
The Swedish railway industry is now calling for legislation that would regulate the placement of 4G towers and base stations in the country, according to Swedish Radio (SR).

"The frequency range of the railroad is regulated by law, and we can't change frequencies, so we have to be sure that we won't be disrupted," said Sven-Håkan Nilsson, director of ERTMS for the Swedish railroad authorities, according to SR.
The long-range plan for the Swedes is to use the ERTMS in such a way that allows trains to cross several European countries, using different railway standards, without any hiccups."


Regards
 04 May 2011 11:35 AM
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dipsikha

Posts: 1
Joined: 02 January 2011

I'm also a communication engineering(2nd year B.tech) student..just knew about this cognitive radio network few months ago..and its so interesting .so i am studying it in more detail...I have a question in CRN the interoperability is a good thing.but it still ideal.ri8??????how can we implement this?and also i have some confusion in the implementation this CRN in MATLAB using fuzzy logic...and we are using dynamic spectrum access and using licensed band by unlicensed users with less priority like BLUETOOTH ...but what about when lots of ppl are using bluetooth at same time...may be its of less priority and not causing interference with licensed users but it can also cause overload during DSA ..so what about that????
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