> : > Normally, Frequency Hopping (FH) and Direct Sequence (DS) types of Spread
> : > Spectrum are both called "CDMA" - so much so that "Code Division, Multiple
> : > Access" essentially means "Spread Spectrum" these days.
> : 
> : I think using CDMA to describe FH is confusing, but who am I to tell...
> 
> CDMA isn't FH at all.  It is spread spectrum in that it uses the
> entire broad spectrum all the time.  All the users share the spectrum
> and you xor your psuedo random number with incoming packets and ignore
> the ones that don't decode right...  At least that's what I learned
> about CDMA phones while I was working at Qualcomm.  I suppose that
> Qualcomm employees with double digit badge numbers would be able to
> explain what things fairly well :-)
> 
> Warner

Qualcomm only does Direct Sequence Spread Spectrum, and calls their stuff
CDMA.

As I mentioned, "CDMA" is a "catch-all" phrase for Spread Spectrum.

I -completely- agree that using it that way is adding to the confusion.

I'm -only- saying that there's confusion out there, and it's better to call
it "Spread Spectrum" - and then specify DS or FH (and, incidentally, there
are other types, such as Time Hopping - but this isn't relevant here.)


-Mike

p.s. I used to teach a course in SS, and have build SS systems, so I'm not
totally clueless, notwithstanding my apparenty inability to communicate
clearly here! ;-)