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Cellular Overview
Introduction
The cellular radio frequency spectrum has
been divided by the FCC into two equal seg-
ments or bands to allow two independent cel-
lular carriers to coexist and compete in the
same geographic coverage area. Each band
occupies one half of the available channels
in the cellular spectrum. Initially there were
666 channels available across the entire cel-
lular spectrum, but that number was ex-
panded to 832 channels in 1987, and with
NAMPS to 2,412 channels in 1991. Digital
cellular promises to make a further expan-
sion. To guarantee nationwide compatibil-
ity, the signaling channel frequencies have
been pre-assigned to each segment (band).
The two bands and their assigned channels
Figure 2. US Cellular Frequency Band
1023
991
001
A'
2
US Cellular Frequency Band
832 channels
313
312
A
Band A
Voice
Channels
© 2000 Motorola, Inc.
are defined in Figure 1.
Originally the B Band was assigned to the
telephone company (referred to by a euphe-
mism, the Wireline carrier). The A Band, by
default, was referred to as the Non-Wireline
carrier, guaranteed competition to the tele-
phone company. Today the terms Wireline
and Non-Wireline have little meaning since
telephone company carriers now operate A
Band systems, and vice-versa.
Control (Data) Channels
A cellular telephone in the cellular system is
under the indirect control of the switch, or
central controller. The central controller uses
dedicated control channels to provide the sig-
333
334
354
355
A
B
Control
Channels
TDMA Secondary
Control Channels
TDMA Timeport™ P8190
667
717
666
716
A'
B'
B
Band B
A'
Voice
Channels
667
717
666
716
688 - 708
737 - 757
799
799
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