Re: [amsat-bb] TDMA - Reading the mail

[Franklin Antonio <antonio@xxxxxxxxxxxx>]

At 10:42 PM 12/20/2000 -0600, Jon Ogden wrote:
>If P51AA decides to go on the air on satellite, there will be a HUGE 
>pileup.  In an analog system, the operator can generally pick out a 
>callsign or two or parts of them from the mess.  However, in a digital 
>system, we have a different problem.  If there are multiple signals of 
>approximately equal strength (and in a satellite situation this is quite 
>likely especially with a high number of users), then as you point out 
>above, we have bit errors and potentially enough to make the whole mess 
>totally unusable.

You're thinking about only one layer of the cake.

The idea is to have a protocol that controls the user terminal 
behavior.  In a TDMA system, the user's terminal (or radio or whatever you 
call it) would get assigned a time slot, and these assignments would be 
made in a such a way that people don't fall on top of one 
another.  Whatever the multiplexing scheme (CDMA, TDMA, XYZMA, etc), the 
protocol would be a set of rules governing user terminal behavior designed 
(among other things) to avoid transmissions which destroy one another.


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