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RE: Amateur radio module on commercial Geo Sat?



At 09:06 AM 12/21/2000 +1100, Tony Langdon wrote:
>Hmm, this is becoming an interesting thread, and some good arguments in
>favour of TDMA for amateur satellite work.  Perhaps we should come up with a
>list of pros and cons for FDMA, TDMA and CDMA.

Unfortunately, I don't think that's possible in the abstract.  (I believe 
that assigning pros and cons to these general terms is often misleading 
rather than helpful.)

These design choices only have pros and cons in the CONTEXT of a particular 
system design.  Therefore, Phil can describe to you his idea for a 
particular TDMA system and how it would work, and we could discuss the pros 
and cons of that system relative to some other system.  However, that 
doesn't mean that all TDMA systems would necessarily have those pros or 
those cons relative to some other system, be it TDMA or FDMA or CDMA or 
something else or some combination.

You spoke about the "alligator problem".  The solution is to design into 
the user terminal some behavioral rules.  In a TDMA system, the rules would 
be to only transmit in your assigned time slot.  If you do that, you won't 
step on other people.  In a CDMA system, the rules would likely be to obey 
some power control algorithm.  Different sort of rule, but might accomplish 
same thing.  Phil described a particular solution, in the context of a 
particular system design.

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