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Re: TDMA - Reading the mail



>channel of the downlink. With a CDMA uplink I suspect that the strongest
>station could wipe out all channels and that is why Phil Karn wasn't
>considering it.

With CDMA, automatic power control would be an absolute must. Then, as
long as you limit the total number of stations transmitting at any
given moment, the receivers would be able to demodulate any or all of
them.

I've not proposed CDMA here for two reasons. First, it requires a
highly linear wideband transponder on the satellite, which implies a
low DC->RF conversion efficiency. (HELAPS would not be practical
because of the wide bandwidth requirement.) Second, it doesn't really
buy you much in a point-to-point link without significant interference
from other users or other satellites.

CDMA still has the potential advantage of eliminating the overhead
traffic necessary to dynamically allocate & deallocate TDMA timeslots,
but I'm not sure how much of an advantage this would be.

Phil


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