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Faisal Khan
Joined: 26 Jun 2003
Posts: 32
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 12 Apr 2006 6:21 Paired carrier multiple Access |
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Hi,
Could anyone guide me abt PCMA... Paired carrier muliple access??
Regards
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mshareef
Joined: 18 Feb 2006
Posts: 203
Helped: 45
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| 12 Apr 2006 7:52 Re: Paired carrier multiple Access |
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This technique allows the transponder bandwidth to be reused by superimposing carriers on top of each other. This has the potential for major savings in space segment rental costs. It is possible when, in the system design, the fractional transponder bandwidth resource is being used up first, before the power resource is fully utilised. This can occur in networks where not all earth stations are of the minimum possible size, from the point of view of receive G/T. In such cases, with modern high sensitivity/high power satellites, it is difficult to simultaneously and efficiently exploit the satellite power and bandwidth resources. The tendency is to run out of bandwidth and resort to abnormally high power spectral density carriers such as 8 PSK or 16 QAM or similar. In PCMA, an earth station knows what it is transmitting and by suitably delaying and then subtracting a weak version of the transmitted signal from the received signal the 'interference' arising from carrier superimposition is eliminated.
And see the attached file also.
http://www.viasat.com/_files/?view=pcma.pdf
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Faisal Khan
Joined: 26 Jun 2003
Posts: 32
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| 13 Apr 2006 0:59 Re: Paired carrier multiple Access |
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Dear Shareef,
I have been working on intrefernce cancellation from regulatory point of view. Now I am starting MS by research in the interference cancellation. I was looking for some specific area to work in and I found this thing. Could you tell me if this is an active field. as it says, it is only applicable to band pipe satellites, but new generation of satellites employ on-board processing, so would this be of some importance in future?
Regards
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mshareef
Joined: 18 Feb 2006
Posts: 203
Helped: 45
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| 13 Apr 2006 8:23 Re: Paired carrier multiple Access |
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It is going to stay at least for some time as the latest technology as claimed by Viasat which has also introduced ArcLight . Arclight is the first interactive VSAT to use CDMA technology along with PCMA.
The following link gives some insight about this:
http://itpapers.zdnet.com/abstract.aspx?docid=72650&promo=999222&kw=A%20Breakthrough%20in%20Satellite%20Communications
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