2. 2G (or 2-G) is short for second-
generation wireless telephone
technology. Second generation 2G
cellular telecom networks were
commercially launched on the
GSM standard.

3. Three primary benefits of 2G networks
over their predecessors were that phone
conversations were digitally encrypted;
2G systems were significantly more
efficient on the spectrum allowing for
far greater mobile phone penetration
levels; and 2G introduced data services
for mobile, starting with SMS text
messages.

4. While radio signals on 1G networks are
analog, radio signals on 2G networks
are digital. Both systems use digital
signaling to connect the radio towers
(which listen to the handsets) to the
rest of the telephone system.

6. GSM (global system for mobile
communication) is a common second
generation cell phone standard.
.GSM is a digital standard that was adopted
over the original analog system.
.THE GSM network operates at 850MHZ
Or 1900MHZ bands in the US.

7. GSM (Global System for Mobile
communication) is a digital mobile
telephone system that is widely used in
Europe and other parts of the world. GSM
uses a variation of time division multiple
access (TDMA) and is the most widely used
of the three digital wireless telephone
technologies (TDMA, GSM, and CDMA).
GSM digitizes and compresses data, then
sends it down a channel with two other
streams of user data, each in its own time
slot.

8. .GSM uses GMSK or Gaussian minimum shift
keying for modulation
.GMSK is a kind of continous frequency
shift keying

9. .The on-off binary signal is first
transformed to a polar binary signal.
.The polar binary signal is filtered
such that a Gaussian-shaped signal is
produced.
.Frequency modulation is then
applied to signal.

10. .The weaker digital signal may not be
able to reach cell tower.
.Digital signal will drop out faster then
an analog signal.

11. .Users separated by code
.Require digital transmission
.Wider bandwidth compared to TDMA
.Introduced in 1980
.Used in cellular communication
system

12. .Generating a CDMA signal
1. Analog to digital conversion
2. Vocoding
3. Encoding and interleaving
4. Channelizing the signal
5. Conversion of digital to
radio frequency signal

13. USER#N
Rate=Rn
User#1,2,3….#n
Cn
User#2 ∑
Rate=R2
C2
User#1
Rate=R1
C1

14. Three of the more common
transmission schemes include FDMA
(Frequency Division Multiple
Access), TDMA (Time Division Multiple
Access), and CDMA (Code Division
Multiple Access).

15. FDMA divides the given spectrum
into channels by the frequency
domain. Each phone call is
allocated one channel for the entire
duration of the call.

16. Frequency Division Multiple Access

17. TDMA enhances FDMA by further
dividing the spectrum into channels by
the time domain as well. A channel in
the frequency domain is divided
among multiple users. Each phone call
is allocated a spot in the channel for a
small amount of time, and "takes
turns" being transmitted

19. Unlike FDMA and TDMA, CDMA
transmission does not work by
allocating channels for each phone
call. Instead, CDMA utilizes the entire
spectrum for transmisson of each call.
Each phone call is uniquely encoded
and transmitted across the entire
spectrum, in a manner known as
spread spectrum transmission.

20. Code Division Multiple Access