CDMA
http://www.ixbt.com/mobile/sys-cdma.html
, , , . - (CDMA - Code Division Multiple Access), , NMT, AMPS . , GSM.
- , . , Qualcom IS-95 (CDMA one) . : Hughes Network Systems, Motorola Samsung.
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GSM . - , GSM . , , 200 .
CDMA Qualcom 800 . CDMA 64 , . CELP 8000 / (9600 / ). 4800, 2400, 1200 /.
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MS | 824,040 848, 860 |
BTS | 869,040 893,970 |
BTS | +/- 5*10^-8 |
MS | +/- 2,5*10^-6 |
QPSK(BTS), O-QPSK(MS) | |
c: 3 40 | 1,25 1,50 |
- | 1,2288 |
BTS 1 | 1 - 1 7 55 |
MS | 1 1 |
: . | 1200 / 9600, 4800 / 9600, 4800, 2400, 1200 / |
BTS | R=1/2, =9 |
MS | R=1/3, K=9 |
6-7 | |
BTS | 50 |
MS | 6,3 1,0 |
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CDMA, AMPS .
CDMA (Forward), - (Reverse). CDMA IS-95 :
CDMA:
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. 64, .. , , 64, 64 . 64 1- (W0) " ", (W32), 7- (W1,W2,W3,W4,W5,W6,W7) , 55 " ".
180 . , . , , .