3. Use of light as communication
heliographs, flags (semaphore), ...
150 BC smoke signals for communication;
(Greece)
1794, optical telegraph, Claude Chappe
Electromagnetic Wave:
1831-79 Faraday and Maxwell demonstrates electromagnetic
induction and theory of electromagnetic fields
H. Hertz (1857-94): demonstrates the wave character of
electrical transmission through space
By : Engr. Abdul Razzaque Memon
4. Attributes of
Telecommunication
Speed
- Ability to transmit in real-time
Coverage
- Regional, National and International
Reliability
Cost
- 1860’s: 20 word telegram $5-$100
Security
By : Engr. Abdul Razzaque Memon
5. High Tech of 19th Century
1850 – First submarine line
1858 – First transatlantic cable
- breaks after 3 month
1866 – Higher quality cable
- London to Bombay in 4 ½ mins.
1924 – Telegram around the world in 80 secs.
By : Engr. Abdul Razzaque Memon
6. 1896 Guglielmo Marconi
first demonstration of wireless
telegraphy
long wave transmission, high
transmission power necessary ( +200kw)
1907 Commercial transatlantic connections
huge ground stations (30 by100m antennas)
1915 Wireless voice transmission NY - SF
1920 Discovery of short waves (< 100m) by Marconi
reflection at the ionosphere
(cheaper) smaller sender and receiver, possible due to the
invention of the vacuum tube (1906, Lee DeForest and Robert
von Lieben)
By : Engr. Abdul Razzaque Memon
7.
1920 First commercial radio broadcast in Pgh.
1928 many TV broadcast trials
1933 Frequency modulation (E. H. Armstrong)
1935 First telephone call around the world
1958, then 1972 A-Netz and B-Netz in Germany
analog, 160MHz, connection setup from the fixed network too (but
location of the mobile station has to be known)
1974 FCC allocates 40Mhz for Cellular telephony
1981 Start of Cellular-specification in Europe (Global
System for Mobile communication)
1983 Start of the American AMPS (Advanced Mobile Phone
System, Analog)
1984 CT-1 standard (Europe) for cordless telephones
By : Engr. Abdul Razzaque Memon
8. 1986 C-Netz in Germany
analog voice, 450MHz, hand-over possible, digital signaling,
automatic location of mobile device
still in use today (as T-C-Tel), services: FAX, modem, X.25, e-mail,
98% coverage
1991 Specification of DECT
Digital European Cordless Telephone (today: Digital Enhanced
Cordless Telecommunications)
- ~100-500m range, 120 duplex channels, 1.2Mbit/s data
transmission, voice encryption, authentication
1992 Start of GSM
fully digital, 900MHz, 124 channels
automatic location, hand-over, cellular
roaming in Europe - now worldwide in more than 100 countries
services: data with 9.6kbit/s, FAX, voice, ...
By : Engr. Abdul Razzaque Memon
9. 1994
E-Netz in Germany
GSM with 1800MHz, smaller cells, supported by 11 countries
1996
Network)
HiperLAN (High Performance Radio Local Area
standardization of type 1: 5.15 - 5.30GHz, 23.5Mbit/s
recommendations for type 2 and 3 (both 5GHz) and 4 (17GHz) as
wireless ATM-networks (up to 155Mbit/s)
1997
Wireless LAN - IEEE802.11
IEEE-Standard, 2.4 - 2.5GHz and infrared, 2Mbit/s
already many products (with proprietary extensions)
1998
Specification of GSM successors
for UMTS (Universal Mobile Telecommunication System) as
European proposals for IMT-2000
By : Engr. Abdul Razzaque Memon
11. Wireless Communication
Transmitting voice and data using
electromagnetic waves in open space
Electromagnetic waves
Travel at speed of light (c = 3x108 m/s)
Has a frequency (f) and wavelength (λ)
c=fxλ
Higher frequency means higher energy photons
The higher the energy photon the more penetrating
is the radiation
By : Engr. Abdul Razzaque Memon
13. Frequency Carries/Channels
The information from sender to receiver is carrier
over a well defined frequency band.
This is called a channel
Each channel has a fixed frequency bandwidth (in
KHz) and Capacity (bit-rate)
Different frequency bands (channels) can be used
to transmit information in parallel and
independently.
By : Engr. Abdul Razzaque Memon
14. Frequency & Wavelength of Some
Technologies
AMPS Phones:
frequency ~= 800 Mhz
wavelength ~= 37.5 cm
GSM Phones:
frequency ~= 900 Mhz
wavelength ~= 33 cm
PCS Phones
frequency ~= 1800 Mhz (1.8 Ghz)
wavelength ~= 16.6 cm
Bluetooth:
frequency ~= 2.4 Gz
wavelength ~= 12.5 cm
By : Engr. Abdul Razzaque Memon
15. Simplex/Duplex Communication
Normally, on a channel, a station can transmit
only in one way.
This is called simplex transmision
To enable two-way communication (called
full-duplex communication)
We can use Frequency Division Multiplexing
We can use Time Division Multiplexing
By : Engr. Abdul Razzaque Memon
16. What is Mobility
Initially Internet and Telephone Networks is designed
assuming the user terminals are static
No change of location during a call/connection
A user terminals accesses the network always from a fixed
location
Mobility and portability
Portability means changing point of attachment to the
network offline
Mobility means changing point of attachment to the
network online
By : Engr. Abdul Razzaque Memon
17. Degrees of Mobility
Walking Users
Low speed
Small roaming area
Usually uses high-bandwith/low-latency access
Vehicles
High speeds
Large roaming area
Usually uses low-bandwidth/high-latency access
Uses sophisticated terminal equipment (cell phones)
By : Engr. Abdul Razzaque Memon
18. Need for Wireless/Mobile Networking
Demand for Ubiquitous Computing
Anywhere, anytime computing and communication
You don’t have to go to the lab to check your email
Pushing the computers more into background
Focus on the task and life, not on the computer
Use computers seamlessly to help you and to make your life
more easier.
Computers should be location aware
Adapt to the current location, discover services
By : Engr. Abdul Razzaque Memon
19. Very Basic Cellular/PCS
Architecture
Public Switched
Telephone Network
Mobility
Database
Base Station
Controller
Mobile
Switching
Center
(MSC)
Radio Network
Base Station
(BS)
By : Engr. Abdul Razzaque Memon
Mobile Station
24. Cellular Networks
First Generation (1G)
Second Generation (2G)
2.5G
Analog Systems
Analog Modulation, mostly FM
AMPS
Voice Traffic
FDMA/FDD multiple access
Digital Systems
Digital Modulation
Voice Traffic
TDMA/FDD and CDMA/FDD multiple access
Digital Systems
Voice + Low-datarate Data
Third Generation (3G)
Digital
Voice + High-datarate Data
Multimedia Transmission also
By : Engr. Abdul Razzaque Memon
25. Data Rates of 1G, 2G, 3G:
2nd Generation
GSM -9.6 Kbps (data rate)
2.5 Generation
HSCSD (High Speed ckt Switched data)
Data rate : 76.8 Kbps (9.6 x 8 kbps)
GPRS (General Packet Radio service)
Data rate: 14.4 - 115.2 Kbps
EDGE (Enhanced data rate for GSM Evolution)
Data rate: 547.2 Kbps (max)
3 Generation
WCDMA(Wideband CDMA)
Data rate : 0.348 – 2.0 Mbps
By : Engr. Abdul Razzaque Memon
26. Upgrade Paths for 2G
Technologies
IS-95
2G
IS-136
PDC
GSM
2.5G
GPRS
IS-95B
HSCSD
EDGE
3G
cdma200-1xRTT
W-CDMA
cdma2000-1xEV,DV,DO
TD-SCDMA
cdma200-3xRTT
By : Engr. Abdul Razzaque Memon
EDGE
28. 2G and Data
2G is developed for voice communications
You can send data over 2G channels by using modem
Provides adat rates in the order of ~9.6 Kbps
Increased data rates are requires for internet
application
This requires evolution towards new systems: 2.5 G
By : Engr. Abdul Razzaque Memon
29. 2.5 Technologies
Evolution of TDMA Systems
HSCSD for 2.5G GSM
Up to 57.6 Kbps data-rate
GPRS for GSM and IS-136
Up to 171.2 Kbps data-rate
EDGE for 2.5G GSM and IS-136
Up to 384 Kbps data-rate
Evolution of CDMA Systems
IS-95B
Up to 64 Kbps
By : Engr. Abdul Razzaque Memon
30. 3G Systems
Goals
Voice and Data Transmission
Simultanous voice and data access
Multi-megabit Internet access
Interactive web sessions
Voice-activated calls
Multimedia Content
Live music
By : Engr. Abdul Razzaque Memon
31. 3G Systems
Evolution of Systems
CDMA sysystem evaolved to CDMA2000
CDMA2000-1xRTT: Upto 307 Kbps
CDMA2000-1xEV:
CDMA2000-1xEVDO: upto 2.4 Mbps
CDMA2000-1xEVDV: 144 Kbps datarate
GSM, IS-136 and PDC evolved to W-CDMA (Wideband
CDMA) (also called UMTS)
Up to 2.048 Mbps data-rates
Future systems 8Mbps
Expected to be fully deployed by 2010-2015
New spectrum is allocated for these technologies
By : Engr. Abdul Razzaque Memon
32. Interest to 3G Applications
Emails
City maps/directions
Latest news
Authorize/enable payment
Banking/trading online
Downloading music
Shopping/reservation
Animated images
2.4
Chat rooms, forums
Interactive games
Games for money
Western
Europe
4.5
4.3
4.0
3.4
3.5
3.1
3.0
Eastern
Europe
4.7
4.2
4.4
3.8
3.4
3.4
3.1
2.7
2.3
2.0
1.8
USA
4.3
4.2
4.0
3.0
3.2
3.2
2.9
2.6
2.9
2.2
1.8
2.2
2.4
1.8
(Means based upon a six-point interest scale, where 6 indicates high interest and 1 indicates low interest.)
By : Engr. Abdul Razzaque Memon