The document summarizes the evolution of wireless communication technologies across four generations: 1) 1G introduced analog cellular networks with poor voice quality and battery life. 2) 2G replaced analog with digital technologies like TDMA and CDMA, increasing capacity 3x but supporting only low data rates. 3) 3G introduced packet-switching and higher data rates of 2Mbps using technologies like WCDMA, though required more power and dense cell tower coverage. 4) 4G uses OFDM and aims to provide 100Mbps speeds by leveraging multiple high-speed networks, but requires new cellular infrastructure and devices.

1. Assignment #1
Submitted by : Akbar Hussain
Reg no : SP15-BEE-008
Wireless communication is exchange of information between sender
and receiver using electromagnetic waves. In past years this technology
has gone significant changes with lot of development. The general
diagram is given by
Figure 1. Overview of Technologies

2. First Generation (1G):
It is an analog communication system introduced in 1980s.
 The system was allocated a 40-MHz bandwidth within the 800 to
900 MHz frequency range by the Federal Communications
Commission (FCC).
 Transmissions from the base stations to mobiles occur over the
forward channel using frequencies between 869-894MHz. And
for reverse using frequencies between 824-849 MHz Advanced
Mobile Phone System (AMPS) and Total Access
Communication Systems (TACS) use the frequency modulation
(FM) technique for radio transmission.
Disadvantages of 1G:
 The quality of voice was poor
 The battery life was poor for the systems of 1G
 Frequent call drops
 The system which was used for 1G was heavy.
Second Generation (2G):
Analog system was replaced with digital technology in second
generation so digital modulation techniques were used in this
generation
 The techniques used in second generation are TDMA (time
division multiple access) and CDMA (code division multiple

3. access) along with the frequency division duplexing (FDD)
technique
 The capacity is three times greater than 1G due to increase in
spectrum efficiency
 GSM (global system for mobile communication) was introduced
in this generation
Disadvantages:
 The enabled GSM systems don’t support high data rates
 Reduce range of sound
 Weaker digital signal
2.5 Generation:
It represents second and half generation.
 It uses GPRS (General Packet Radio Service). GPRS could
provide data rates from 56 kbit/s up to 115 kbit/s.
 It can be used for services such as Wireless Application
Protocol (WAP) access, Multimedia Messaging Service
(MMS), and for Internet communication services such as
email and World Wide Web access.
Third generation (3G):
3g service supports the services which are at least 2Mbps
The spectral efficient is better than the previous services
 packet switching was used in this generation
 Both QAM (Quadrature Amplitude Modulation) and QPSK
(Quadrature Phase Shift Keying) are modulation techniques used

4. in IEEE 802.11 (Wi-Fi*), IEEE 802.16 (WiMAX) and 3G
(WCDMA/HSDPA) wireless technologies.
 The modulated signals are then demodulated at the receiver
where the original digital message can be recovered.
 The use of adaptive modulation allows wireless technologies to
optimize higher throughputs while also covering long distances.
Disadvantages:
 The usage of power is more due to high data rates
 Base stations should be close which proves that this service is
expensive
 Service provider have to pay for licensing.
Fourth Generation (4G):
It is the present technology used by many mobile companies.

5.  Carriers that use orthogonal frequency-division multiplexing
(OFDM) instead of time division multiple access (TDMA) or
code division multiple access (CDMA)
 According to the ITU, a 4G network requires a mobile device
to be able to exchange data at 100 Mbit/sec.
 4G is expected to enable pervasive computing, in which
simultaneous connections to multiple high-speed networks
will provide seamless handoffs throughout a geographical
area
Disadvantages:
 New cells in towers
 High data prices
 Consumers have to change their devices
THE END