5 MHz "channel" / 1.25 MHz "channel" -- okay, once and for all, I would like to see if my understanding of this "slice of electromagnetic spectrum" stuff is indeed correct ...
My guess is : the FCC assigns a certain portion of the electromagnetic spectrum to each carrier (e.g. -- Sprint PCS, Verizon, Globalstar, etc.)
This portion (or "slice," as I like to call it) has some "width" (or range of wavelengths).
The Globalstar literature I picked up at Qualcomm annual meetings had the following information (relating to the Qualcomm GSP 1600 model of Globalstar handset) :
Globalstar Reverse link : 1610.73 to 1625.49 MHz
Globalstar Forward link : 2484.39 to 2499.15 MHz
Cellular Reverse link : 824.01 to 848.97 MHz
Cellular Forward link : 869.01 to 893.97 MHz
********************************************
The Globalstar literature I picked up from my (old) Globalstar service provider (GMPCS Personal Communications) had the following information (relating the Globalstar system) :
Globalstar : L and S band
IS-95 CDMA : 824 - 849 MHZ, 869 - 894 MHz
AMPS : 824 - 849 MHz, 869 - 894 MHz
GSM : 890 MHz - 915 MHz, 935 - 960 MHz
(I assume that the whole numbers are merely the result of someone deciding to "round" the numbers).
Questions :
1. Is this "reverse" and "forward" terminology referring to the call coming from, or going to the cell tower (or low Earth orbit satellite) ?
2. Are these various "slices of spectrum" (looks like 25 MHz wide for the various cellular choices, and 15 MHz for Globalstar satellite telephony) -- the place where the carriers have to "fit" their 1.25 MHz or 5 MHz channels ?
3. If this is correct, and spectrum is obviously a limited and valuable resource, why would anyone EVER adopt W-CDMA technology, if it requires 5 MHz, instead of 1.25 MHz ?
Jon. |
