563489578934

TABLE 8–11
2G MAJOR DIGITAL CELLULAR TELEPHONE SYSTEMS
System Name a and Where Used
Item
GSM
Europe, Asia
IS-136 (D-AMPS)
North America
IS-95 (Cdma One)
North America, Asia
iDEN
North America
Year introduced 1990 1991 1993 1994
Base cell station h
Transmit bands (MHz) 935–960 869–894 869–894 851–866,
Mobile station h
Transmit bands (MHz) 890–915 824–849 824–849 806–821
Maximum power (watts) 20 3 0.2 3
Number of duplex channels 125 832 20 600
Channel bandwidth (kHz) 200 30 1250 25
Channel access method TDMA TDMA CDMA f TDMA
Users per channel 8 3 35 g 3
Modulation b
Type GMSK p> 4 DQPSK
QPSK quad-16QAM
Data rate
270.833 kb> s 48.6 kb> s
9.6 kb> s f
64 kb>
s
Filter 0.3R Gaussian c r = 0.35 raised cosine d r = 0.2 raised cosine d
Speech coding e RPE-LTP VSELP QCELP VSELP
13 kb> s
8 kb> s
8 kb> s (variable) 8 kb>
s
a GSM, group special mobile; NADC, North American digital cellular; iDEN, Integrated digital enhanced network.
b GMSK, Gaussian MSK (i.e., h = 0.5 FSK, also called FFSK, with Gaussian premodulation filter; see Sec. 5–11 and footnote c; p4 DQPSK, differential QPSK with p4
rotation of reference phase for each symbol transmitted; quad-16QAM is four 16QAM carriers for each signal).
c Baseband Gaussian filter with 3 dB bandwidth equal to 0.3 of the bit rate.
d Square root of raised cosine characteristic at transmitter and receiver.
e RPE-LTP, regular pulse excitation—long-term prediction; VSELP, vector sum excited linear prediction filter; QCELP, Qualcomm’s codebook excited linear prediction.
f The spread spectrum chip rate is 1.2288 Mchipss, for a spreading factor of 128 or 21-dB processing gain.
g For CDMA, channel frequencies may be reused in adjacent cells; other methods (TDMA and FDMA) require a seven-cell reuse pattern.
h For 1,900-MHz-band PCS system, the base station transmit band is 1,930–1,990 MHz and the mobile station transmit band is 1,850–1,910 MHz.
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