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spectrum
allocation
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n |
in
1978 Europe allocated 2x25 MHz in the 900 MHz range for
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mobile
communications
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– |
890
- 915 MHz for the uplink (mobile station to base station)
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– |
935
- 960 MHz for the downlink (base station to mobile station)
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n |
top
10 MHz in each band reserved for a pan-European mobile
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system,
since band was also used by national analog systems
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multiple
access:
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n |
GSM
divides allocated bandwidth into carriers spaced 200 kHz
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apart,
starting 200 kHz from the edge - maximum of 124
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carriers
in GSM900, 374 carriers in DCS1800 (2x75 MHz
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allocation)
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n |
TDMA
divides time on each carrier frequency into burst
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periods
lasting 15/26 (0.577) ms
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