Evolution from 1G to 4G involves major technological advancements in wireless networks. 1G networks provided basic voice calling using analog signals, while 2G introduced digital networks like GSM. 2.5G added packet-switched data to GSM. 3G networks supported higher speeds up to 2Mbps for multimedia applications. 4G aims to provide ubiquitous high-speed mobile internet access at speeds over 100Mbps through integrated technologies like OFDM, MIMO, and software-defined radio.

1. Evolution from
1G to 4G
Technologies
By
Dr. Muhammad Moinuddin

2. The First Mobile Generation 1G
 Goal: Provide basic voice service to mobile users over
large area
 1 G Systems developed late 70’s early 80’s, deployed in
80’s
 Advanced Mobile Phone System (AMPS) - USA
 Total Access Communications Systems (TACS) - UK
 Nordic Mobile Telephone (NMT) System – Scandanavian
 C450 - W. Germany
 NTT System - Nippon Telephone & Telegraph (NTT) – Japan
 Incompatible systems using different frequencies

3. Characteristics of 1G systems
 Use Cellular Concept to provide service to a geographic
area (i.e. number of small adjacent cells to provide
coverage)
 Frequency Reuse
 Handoff/Handover
 FDMA/FDD systems
 Macro Cells : 1-40 km radius
 Focus on AMPS system

4. AMPS
 Advanced Mobile Phone System is first generation
wireless in US
 Earlier systems used line of sight radio (eg, AT&T’s
Improved Mobile Telephone Service in 1960s)
 AT&T developed cellular concept in 1940s
 1971 proposed High Capacity Mobile Phone Service to
FCC
 1979 FCC standardized it as AMPS in 800-900 MHz
range
 1983 launched in Chicago

5. AMPS (Contd.)
 Originally 40 MHz of spectrum separated into two bands
of 20 MHz each (A and B band). Later expanded to 25
MHz each.
 FDD used with 45 MHz separation in uplink and downlink
– prevents self interference.
 AMPS uses 30 kHz radio channels between mobile
station and base stations
 Two service providers in area are each allocated 25
MHZ => 12.5 MHz for each direction => 416 pairs of
channels: split into 395 voice channels + 21 control
channels for signaling

6. AMPS (Contd.)
 Channels numbered consecutively 1-666 , when
expanded kept same numbering assuming 30 KHz
channels even in places were no spectrum allowed
 f(c)uplink = 825,000 + 30 x (c) KHz 1 ≤ c ≤ 799
 f(c)uplink = 825,000 + 30 x (c-1023) KHz 991 ≤ c ≤ 1023
 f(c)downlink = f(c)uplink + 45,000 KHz

7. AMPS Frequency Allocation
and Channels

9. Sectored Frequency Planning
for AMPS
 AMPS operators typically used either
clusters of size 21 with no sectoring or
clusters of 7 in cell frequency reuse
pattern with 3 sectors per cell
 Use a Frequency Chart to plan cells:
groups frequencies into 21 categories
Cells 1-7 and sectors A,B,C in each cell

10. AMPS Sector Planning

11. The Second Mobile Generation 2G
 The second generation (2G) of the
wireless mobile network was based on
low-band digital data signaling.
 The most popular 2G wireless technology
is known as Global Systems for Mobile
Communications (GSM).
 The first GSM systems used a 25MHz
frequency spectrum in the 900MHz band.

12. 2G Technologies
 Global System Mobile (GSM)
 Interim-Standard 136 (IS-136) or North
America Digital Cellular (NADC) or US
Digital Cellular (USDC)
 Pacific Digital Cellular (PDC)
 Interim-Standard 95 Code Division
Multiple Access (CDMA) (IS-95 or
cdmaOne)

13. GSM Architecture
 The available 25MHz of bandwidth into 124 carrier
frequencies of 200 kHz each.
 Each frequency is then divided using a TDMA
scheme into 8 timeslots and allows eight
simultaneous calls on the same frequency.
 TDMA breaks down data transmission, such as a
phone conversation, into fragments and transmits
each fragment in a short burst, assigning each
fragment a time slot.
 Today, GSM systems operate in the 900MHz and
1.8 GHz bands throughout the world with the
exception of the Americas where they operate in the
1.9 GHz band.

14. Interim Standard-36 (IS-136)
 Started in 1991
 Also known as North American Digital Cellular
(NADC) or US Digital Cellular (USDC)
 Uses π/4-DQPSK, speech coding
 Uses TDMA with 3 time slotted users for each
30 kHz radio channel.
 Capacity improvement is 3 times that of AMPS
and later 6 times due to advancement in DSP

15. Pacific Digital Cellular (PDC)
 A Japanese TDMA standard that is similar
to IS-136 with more than 50 million users.

16. Interim Standard-95 (IS-95)
 It is a popular 2G CDMA standard.
 Supports up to 64 users that are
orthogonally coded and simultaneously
transmitted on each 1.25 MHz channel.

17. CDMA
 While GSM technology was developed in
Europe, CDMA (Code Division Multiple Access)
technology was developed in North America.
 CDMA uses spread spectrum technology to
break up speech into small, digitized segments
and encodes them to identify each call.
 CDMA distinguishes between multiple
transmissions carried simultaneously on a single
wireless signal.

18. Migration from 2G to 3G
Figure 2.3 Various upgrade paths for 2G technologies.

19. Why 2.5G ?
 The Second Generation (2G) wireless networks are
mostly based on circuit-switched technology which
limit the data user to a single circuit switched voice
channel
 2G are thus, limited to data throughput rate of an
individual user (approx on the order of 10kbps),
 2G wireless technologies can handle some data
capabilities such as fax and short message service
(SMA) at the data rate of up to 9.6 kbps, but it is not
suitable for web browsing, rapid email, and
multimedia applications.

20. Features of 2.5G
 It allow existing 2G equipment to be modified and
supplemented with new infrastructure to support
high data rate transmission for
 Web browsing
 Email
 Mobile-Commerce (m-commerce)
 Location based mobile services
 Support Wireless Application Protocol (WAP)
 WAP is web browsing format language that allows
standard web pages to be viewed in a compressed
format

21. 2.5G Standards
 So-called ‘2.5G’ systems are introduced to
enhance the data capacity of GSM and
mitigate some of its limitations.
 These systems add packet data capability
to GSM networks.
 2.5G standards are IS-95B, HSCSD,
GPRS, EDGE technologies.

22. 2.5G Technologies
 IS-95B (cdmaOne is upgraded which uses higher
data rate than IS-95 and more efficient Handoff
techniques)
 HSCSD (High Speed Circuit Switched Data) use a
circuit switched technique in GSM network. Uses
consecutive time slots instead of one which
increases the data rate from 9,600 bps to 14,400
bps. By using 4 consecutive time slots it increases
to 57.6 kbps

23. 2.5G Technologies (Contd.)
 GPRS (General Packet Radio Services) is a
packet based data network.
 Unlike HSCSD, which dedicates circuit switched
channels to specific users, GPRS supports circuit
switching for multi-user network sharing of
individual radio channels and time slots.
 EDGE (Enhanced Data rate for GSM Evolution)
introduces 8-PSK in addition to GSM’s standard
GMSK modulation.
 EDGE allows for 9 different air interface formats
known as multiple modulation and coding schems
(MCS) with varying degree of error control protection.

24. GPRS vs WAP
 WAP defines how Web pages and similar data
can be passed over limited bandwidth wireless
channels to small screens being built into new
mobile telephones.
 GPRS defines how to add IP support to the
existing GSM infrastructure.
 Theoretical maximum speeds of up to 171.2
kilobits per second (kbps) are achievable with
GPRS using all eight timeslots at the same time.
 This is about ten times as fast as old Circuit
Switched Data services on GSM networks.

25. Third Mobile Generation Networks (3G)
 All 2G wireless systems are voice-centric.
 GSM includes short message service
(SMS), enabling text messages of up to
160 characters to be sent.
 Most 2G systems also support some data
over their voice paths, but at painfully slow
speeds usually 9.6 Kb/s or 14.4 Kb/s.

26. 3G Planning
 Planning for 3G started in the 1980s.
 Initial plans focused on multimedia applications
such as videoconferencing for mobile phones.
 The First Key Issue is the evolution of Internet.
 It is clear that the real killer application was the
Internet.
 Personal wireless Internet access will follow and
users will want broadband Internet access
wherever they go.

27. 3G Planning
 The second key issue for 3G wireless is
that users will want to roam worldwide and
stay connected.
 Today, GSM leads in global roaming.

28. 3G Planning
 The third issue for 3G systems is capacity.
 Cells can be made smaller, permitting
frequency reuse, but only to a point.
 The next step is new technology and new
bandwidth.

29. 3G Specifications
 Today's 3G specifications
 144 Kb/s while the user is on the move in an
automobile or train
 384 Kb/s for pedestrians
 2 Mb/s for stationary users
 That is a big step up from 2G bandwidth
using 8 to 13 Kb/s per channel to transport
speech signals.

30. 3G Evolution
 International Mobile Telecommunications-2000
(IMT-2000) is the official International
Telecommunication Union name for 3G and is
an initiative intended to provide wireless access
to global telecommunication infrastructure
through both satellite and terrestrial systems,
serving fixed and mobile phone users via both
public and private telephone networks.

31. 3G Requirements
 Third-generation wireless also requires new
infrastructure.
 There are two mobility infrastructures in wide use:
 GSM has the mobile access protocol, GSM-MAP
 The North American infrastructure uses the IS-41 mobility
protocol.
 These protocol sets define the messages passed
between home location registers and visitor location
registers when locating a subscriber and the messages
needed to deal with hand-offs as a subscriber moves
from cell to cell.

32. 3G Technologies
 3GPP
 3G W-CDMA (used in Universal Mobile
Telecommunication Systems (UMTS))
 TD-SCDMA (Time Division Synchronous CDMA)
proposed by Japan.
 It uses infrastructure of GSM networks.
 It combines TDMA and TD techniques.
 3GPP2
 3Gcdma2000: provides evolutionary higher data rate
upgrade path for users of 2G and 2.5G.

33. 3G UMTS : W-CDMA
 UMTS use the radio technology called W-CDMA
(Wideband Code Division Multiple Access).
 W-CDMA is characterized by the use of a wider
band than CDMA.
 W-CDMA has additional advantages of
 Supports packet data rate up to 2 Mbps. Thus,
allowing transmission of high quality data, multimedia,
streaming audio, streaming video, broadcast-type of
services, and many others.
 Increased system capacity, and communication
quality by statistical multiplexing.

35. Wireless Local Loop (WLL)
 It uses Fixed Wireless Terminal (FWT)
units which differ from conventional mobile
terminal units operating within cellular
networks such as GSM - in that a fixed
wireless terminal will be limited to an
almost permanent location with almost no
roaming abilities.
 Can provide VOIP

36. Local Multipoint Distribution Service(LMDS)
 LMDS was conceived as a broadband, fixed
wireless, point-to-multipoint technology for utilization
in the last mile (shorter distance).
 Throughput capacity and reliable distance of the link
depends on common radio link constraints and the
modulation method used – either PSK or AM. In
general deployment links of up to 5 miles (8 km)
from the base station are possible, but distance is
typically limited to about 1.5 miles (2.4 km) due to
fade attenuation constraints.
 Some point-to-point systems also use the LMDS
frequencies and can reach slightly farther distances
due to increased antenna gain.

38. Future Mobile Generation Networks
(4G)
 The new 4G framework to be established will try
to accomplish new levels of user experience and
multi-service capacity by,
 Integrating all the mobile technologies that exist
 GSM - Global System for Mobile Communications,
 GPRS - General Packet Radio Service,
 IMT-2000 - International Mobile Communications,
 Wi-Fi - Wireless Fidelity,
 Bluetooth etc.

39. 4G Objectives
 The main objectives of 4G networks can
be stated in the following properties:
 Ubiquity
 Multi-service platform
 Low bit cost

40. Ubiquity
 Ubiquity means that this new mobile network
must be available to the user,
any time, anywhere.
 To accomplish this objective services and
technologies must be standardized in a
worldwide scale.
 Furthermore the services to be implemented
should be available not only to humans as have
been the rule in previous systems, but also to
everything that needs to communicate.

41. Multi-Service Platform
 A multi-service platform is an essential
property of the new mobile generation, not only
because it is the main reason for user transition,
but also because it will give telecommunication
operators access to new levels of traffic.
 Voice will loose its weight in the overall user bill
with the raise of more and more data services.

42. Low-Bit Cost
 Low-bit cost is an essential requirement
in a scenario where high volumes of data
are being transmitted over the mobile
network.

43. Key 4G technologies
 Orthogonal Frequency Division
Multiplexing (OFDM)
 Software Defined Radio (SDR)
 Multiple-input multiple-output (MIMO)

46. Migrating to 4G

47. What is 4G?
 Fourth Generation Technology
 Faster and more reliable
 100 Mb/s (802.11g wireless = 54Mb/s, 3G =
2Mb/s)
 Lower cost than previous generations
 Multi-standard wireless system
 Bluetooth, Wired, Wireless (802.11x)

48. What is 4G?
 Ad Hoc Networking
 IPv6 Core
 OFDM used instead of CDMA
 Potentially IEEE standard 802.11n
 Most information is proprietary

49. Communications Architecture
 Broadcast layer: fix access points, (i.e. cell tower)
connected by fiber, microwave, or satellite (ISP)
 Ad-hoc/hot-spot layer:wireless LANs (ie. internet
at Starbuck’s).
 Personal Layer Gateway:devices that connect to
upper layers; cell phone, fax, voice, data modem,
MP3 players, PDAs.
 Info-Sensor layer:environmental sensors.
 Fiber-optic wire layer: high speed subterranean
labyrinth of fiber optic cables and repeaters

50. Ad Hoc/Mesh Networks
 Spontaneous self organization of networks
of devices
 Not necessarily connected to internet
 4G will create hybrid wireless networks
using Ad Hoc networks.
 Form of mesh networking–Very reliable

51. Wireless Mesh Networks

53. Smart Antennas
 Beam radio signals directly at a user to follow the
user as they move
 Allow the same radio frequency to be used for other
users without worry of interference
 Can’t keep up transmission speeds while device is
moving fast (i.e. in a car)
 Only 32Mb/s at 62mph (vs100Mb/s)
 Seamless handoff between towers/access points
 One transmit antenna, two receive antennas
 Allows connection to two access points at once

55. OFDM
 Orthogonal Frequency Division Multiplexing
 Allows for transfer of more data than other forms of
multiplexing (time, frequency, code, etc)
 Simplifies the design of the transmitter & receiver
 Allows for use of almost the entire frequency band
 No gaps to prevent interference needed
 Currently used in WiMax(802.16) and Wi-
Fi(802.11a/g)

56. How OFDM works
 The frequencies are spaced so that the signals do
not interfere with each other (no cross talk)
 Parallel Data Transmission -Allows for the sending
of multiple signals simultaneously from the same
antenna (or wire) to one device.

57. MIMO Systems