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ADVANTAGES OF CDMAjNo SIM card is required.
jImproved call quality: CDMA provides better and more
consistent
sound quality than systems based on other technologies.
jEnhanced privacy when compared to systems using other
technologies.
jThey are difficult to intercept for an unauthorized person.
jIncreased talk time and standby time for mobiles.
jThey are easily hidden. For an unauthorized person, it is
dufficult to everdetect their presence in many cases.
jThey are resistant to jamming.
jCapacity increases of 8 to 10 times that of an AMPS Analog
system, and
4 to 5 times GSM , because of CDMAs unique spread spectrum
technology.
jMany users can share the same carrier frequency, and without
time-
sharing. This means that mobile phone
service providers can handle more customers on a CDMA network
than on a
GSM network.
jImproved call quality, with better and more consistent sound ,
CDMA
systems use precise power controlthat is, the base station sends
commands to
every mobile phone currently involved in a call, turning down
the power on the
nearby ones, and increasing the power of those further away. The
result is a
nice, even noise level across the carrier, with lower overall
power levels and no
spiky interference.
jIn this civilized atmosphere, each station can easily pick out
its own
coded data frames, decode them and deliver a clean end result.
Dropped calls
are minimized by CDMA's unique ability to keep every sector of
every cell on the
same frequency, so handoffs are "soft" as the mobile phone moves
from one
area to the next. (There is no hole in the signal as one cell is
dropped and
another is acquired.)
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jCDMA decoders interpret constant sounds, such as road noise,
as
having no useful content, and ignore them as much as
possible.
jSimplified system planning through the use of the same
frequency in
every sector of every cell. Other types of systems (analog, GSM,
etc.) need to
break up their frequency spectrum allotments so that each cell
uses a different
frequency. And since no two adjoining cells can use the same
frequency, a given
cell has to be surrounded by a circle of six other cells, all of
which have to be
on different frequencies. This translates to frequency re-use of
only 1 in 7, and if
you change one (by adding a cell for example), the effects
ripple through the
system.
jTo an eavesdropper, the call looks like unintelligible noise.
CDMA was
originally developed by the military for this very reason.
jCDMA providers have no such planning earaches, since every
sector of
every cell uses the same frequency. Enhanced Privacy is inherent
in the way
CDMA works. Each call is spread over the entire 1.25 MHz
carriermuch wider
bandwidth than is needed for a single call.
jThe data bits used to convey real information are mixed with
digital
coding that is known only to the base station and the individual
mobile phone.
jImproved coverage characteristics, allowing for the possibility
of fewer
cell sites This comes from the accurate power control of all
mobile phones using
