1. Mobile Communication Systemsy
Part 1- Introduction & Principles
Professor Z GhassemlooyProfessor Z Ghassemlooy
School of Computing, Engineering and
Information Sciences
School of Computing, Engineering and
Information Sciences
University of Northumbria
U.K.
University of Northumbria
U.K.
Prof. Z. Ghssemlooy
http://soe.unn.ac.uk/ocrhttp://soe.unn.ac.uk/ocr
2. Reading List
- Mobile and Data Communications Systems, D Wong, D Britland, Pub: Artech Housey , g, ,
- Mobile Communications, A Jagoda, M DeVillepin, Pub: J. Wiley
- Mobile Information Systems, Editor: J. Walker, Pub: Artech House
- Introduction to Digital Mobile Communications, Y Akaiwa, Pub: J. Wiley
Mobile Communications 2nd Ed J Schiller ISBN 0 321 12381 6- Mobile Communications, 2nd Ed, J Schiller, ISBN 0-321-12381-6
- Wireless Communications & Networks – Stallings
- Mobile Communications – Dr. J. Schiller
- 3G Wireless Demystified - Hartey
-Introduction to Telecommunications - Anu Gokhale
- Mobile Communication Systems, Parsons J D and Gardiner J G, Blackie USA Halsted
Press
Mobile Communications Engineering Lee William C Y McGraw Hill Inc- Mobile Communications Engineering, Lee, William C. Y., McGraw-Hill, Inc.
- Mobile Cellular Telecommunications Systems, Lee, William C. Y., McGraw-Hill, Inc.
Websites:Websites:
- IEC Online Education
- How Stuff works
- Teracom Training Institute
Prof. Z. Ghssemlooy
g
- Telecom Writing
3. Contents
Frequency Band
History Part Iy
Principles
Transmission PropertiesTransmission Properties
Cellular Concept
T ffi E i iTraffic Engineering
Propagation
Modulation
Performance
Prof. Z. Ghssemlooy
4. Frequency Bandsq y
VHF (30 MH 300 MH )VHF (30 MHz - 300 MHz)
VHF Mid B d (70 87 5 MH )– VHF Mid Band (70 - 87.5 MHz)
– VHF High Band (148 - 174 MHz)
UHF (300 MHz - 3 GHz)
– UHF Band (403 - 420 MHz)
– UHF Band (450 - 520 MHz)UHF Band (450 520 MHz)
– UHF Band 900 MHz (820 - 960 MHz) ⎫
– UHF Band 1.9 GHz (1880 - 1900 MHz) ⎫
Prof. Z. Ghssemlooy
( )
5. Mobile Services
Private Mobile Radio (PMR) System ⎫ate ob e ad o ( ) Syste ⎫
– Conventional Mobile Radio Systems
• Simple two-way radio
• Fixed frequency assignment• Fixed frequency assignment
• Generally no privacy
– Trunked Mobile Radio Systems
C ll l t k hit t• Cellular network architecture
• Efficient use of the frequency spectrum
• Intelligent radio equipment
Cordless Telephone Systems (e.g. DECT)
– Analogue Cellular Phone Systemsg y
– Digital Cellular Phone Systems ⎫
– Personal Communication Systems
Prof. Z. Ghssemlooy
– Mobile Data Services
6. Mobile Communications - Historyy
1934 AM based: 1st Generation Analogue Cellular Systems1934-
USA
AM based: 1st Generation Analogue Cellular Systems
- For public safety
- 5000 mobiles
- Vehicle ignition noise a major problem
1935
USA
E
FM based: - Frequency bands:
- 800 - 900 MHz and 400 - 500 MHz
- 120 kHz RF bandwidth channel spacing of 30 kHzEurope
Asia
- 120 kHz RF bandwidth, channel spacing of 30 kHz
- Data rate 5 - 10 kbps
- No of channels 400 – 1000, half-duplex
1946-
USA
First Generation Public Mobile Telephone Service:
- Coverage distance: 50 km, 60 kHz bandwidth
Prof. Z. Ghssemlooy
- Single powerful transmitter
7. History - 1st Generation (1G) Systemsy ( ) y
1960 Cellular Radio, developed by Bell Labs., p y
19 0 C ll l M bil S t (USA)1970 Cellular Mobile System (USA)
1980 First Generation Analogue Cellular Systems
- Advanced Mobile Telephone Systems (AMPS)- Advanced Mobile Telephone Systems (AMPS)
- Frequency bands: 800 - 900 MHz and 400 - 500
MHz
Ch l i 30 kH d f h l 400- Channel spacing 30 kHz and no of channels 400
– 1000
- Data rate 5 - 10 kbps
Prof. Z. Ghssemlooy
p
-FM for speech, FSK for signalling, FDM
8. History - 2nd Generation (2G) Systems
(1991 4)(1991-4)
Systems:
- 1991 First Group Special Mobile (GSM) network, Finland
- 1992 Commercial GSM, all major European operators
- 1992 Japanese Digital Cellular (JDC) system
- 1993 GSM1800 system in commercial operation, UKy p ,
- 1994 Commercial operation of D-AMPS (IS-54), US
- U.S. Digital Cellular (USDC) and CDMA
• Technology: TDMA, TDMA hybrid FDMATechnology: TDMA, TDMA hybrid FDMA
• Characteristics:
• Digital voice and low speed data
• Frequency band @ 900 MHz, RF channel spacing 200 kHz
• Modulation: GMSK, DPSK, Fixed frequency assignment
• Speech rate 13 kbps, Speech coding, TDMA
• High security and higher capacity,
• Improved speech Quality of service (QoS)
1. NEC Cellstar 500 series (1992)
2. Nokia 2110 series (1994)
3 N ki 5120 (1998)• Improved speech Quality of service (QoS)
• GSM 1.8 GHz, and 1.9 GHz
USDC 1 9 GH
3. Nokia 5120 (1998)
4. Kyocera 2135 (2002)
5. Audiovox CDM8300 (2002)
6. Samsung SCH-A650 (2004)
Prof. Z. Ghssemlooy
• USDC 1.9 GHz
• Digital Cordless Systems (DCS) 1.8 GHz
9. Current - 3rd Generation (3G) Systems
(1995 )(1995 - )
Support Multimedia Services:
– Especially Internet Service, 144kb/s (Outdoor and higher velocity ),
– 384kb/s(from outdoor to indoor) and 2Mb/s (indoor);
– Speech of QoS and other services
First Transitional System: 2 GHz
2000 - 2nd Transitional Systems: 2.5 GHz
2001 1st CDMA Network @ 144 k bps2001 - 1st CDMA Network @ 144 k bps
2002- Handover between GSM and WCDMA by Nokia and Vodafone
2003 World's 1st IPv6 over 3G UMTS/WCDMA network, Ericsson,
2003 World's 1st CDMA2000 high-speed packet data phone call ( 3.09
Mbps), Nokia
2004 World's 1st Enhanced Datarate for Global Evolution2004, World's 1st Enhanced Datarate for Global Evolution
EDGE-WCDMA 3G packet data handover, Nokia and TeliaSonera
2005, 9 Mbps with WCDMA, HSDPA phase 2, Ericsson
Prof. Z. Ghssemlooy
, p , p ,
2005, 1.5 Mbps enhanced uplink WCDMA system, Ericsson
10. Current - 3G Systemsy
Are referred to as:Are referred to as:
Universal Mobile Telecommunications System (UMTS) in
Europe
International Mobile Telecommunications 2000 (IMT2000)
worldwide.
“UMTS will be a mobile communications system that can offer
significant user benefits including high-quality wireless
multimedia services to a convergent network of fixedmultimedia services to a convergent network of fixed,
cellular and satellite components. It will deliver information
directly to users and provide them with access to new and
innovative services and applications It will offer mobileinnovative services and applications. It will offer mobile
personalised communications to the mass market
regardless of location, network and terminal used”.
Prof. Z. Ghssemlooy
UMTS Forum 1997
11. UMTS - Main Requirements (3 Ms)q ( )
Multi-media
Multi-environment
M lti t Vi t l tMulti-operator Virtual operators
Global
Different environments for UMTS
Suburban
Urban
Micro-Cell
In- Building
H C ll
Macro-Cell Pico-Cell
Home-Cell
Prof. Z. Ghssemlooy
H. Aghvami, KCL,UK
12. Mobile Telephony Standardsp y
A C P id Wh t’ Will P idAccess
Standard
Company Provides What’s
Coming
Will Provide
CDMA / TIA Verizon Voice, Data, 1XEV-DO 300-500 kbps, to
95 PTT, 1xRTT CDMA-2000 2.4 Mbps
TDMA / TIA
136
Cingular /
AT&T
Voice, Data Edge 384 kbps data
136 AT&T
CDMA / PCS Sprint Voice, Data 1XEV-DV to 3.1 Mbps
TDMA / iDEN Nextel Voice, Data,
PTT
Spectrum
change
Address public
safety concern
GSM T-Mobile Voice Data GPRS W- 115 kbps dataGSM T Mobile,
AT&T
Voice, Data GPRS, W
CDMA, PTT
115 kbps data
Prof. Z. Ghssemlooy
Source: IEEE
13. Technologies - Multimedia Messaging
Service (MMS)Service (MMS)
It d d iIt d d iIt send and receives:
–Text messages
Graphics and Photos
It send and receives:
–Text messages
Graphics and Photos–Graphics and Photos
–Audio, video clips
–Graphics and Photos
–Audio, video clips
Multimedia
It supports:
–Image: GIF, JPEG,
It supports:
–Image: GIF, JPEG,
Multimedia
Messaging
Service Image: GIF, JPEG,
–Video: MPEG4
–Audio: MP3, MIDI
Image: GIF, JPEG,
–Video: MPEG4
–Audio: MP3, MIDI
Service
(MMS)
For high transmission speed uses:
3G
For high transmission speed uses:
3G
Prof. Z. Ghssemlooy
- 3G
- GPRS: General Packet Radio Service
- 3G
- GPRS: General Packet Radio Service
14. Technologies - General Packet Radio
Service (GPRS)Service (GPRS)
Packet based:
– subs are always on line
– easy and quick accessy q
Provide high speed wireless Internet and data
communicationscommunications
Speed four times higher than conventional GSM
systemssystems
Prof. Z. Ghssemlooy
15. Technologies - Bluetoothg
Short range RF technology
A global standard
No wiring
Data and voice communications
Offers ad hoc network and synchronicity between all
personal devicespersonal devices
Prof. Z. Ghssemlooy
17. Number of mobile phone subscribers in
UKUK
http://www.mobilemastinfo.com/information/history.htm
Prof. Z. Ghssemlooy
18. Mobile Internet Outlook
Millions
1,400
Projected
cellular1,400
1,200
More handsets than PCs
cellular
subscribers
(Nokia 1999)
1,000
connected to the Internet by the
end of 2003 !
Projected Web
800
600
Projected Web
handsets
(Nokia 1999)
400 Projected PCs
connected to
the Internet
200
0
the Internet
(Dataquest 10/98)
Prof. Z. Ghssemlooy
1996 1997 1998 1999 2000 2001 2002 2003 2004 2005
0
19. Mobile Network in UK
5 network operators
45,000 base station sites.
2/3 i t ll d i ti b ildi t t2/3 are installed on existing buildings or structures.
< 2% are mounted on schools.
Additional mobile phone base stations will need to
be built to support 3G services. It is possible that the
number of base station sites will rise to 50,000 by
Prof. Z. Ghssemlooy
2007.
20. Mobile Communications - Definition
Designed to operate over a very large area with aDesigned to operate over a very large area with a
limited bandwidth
A cellular mobile comms system uses a large numberA cellular mobile comms. system uses a large number
of low-power wireless transmitters (100 W oe less)
Off l it th h ll littiOffers larger capacity through cell splitting
Variable power levels allow cells to be sized according
to subscriber density& demand within a particular region
As mobile users travel from cell to cell theirAs mobile users travel from cell to cell, their
conversations are handed off between cells
Channels (frequencies) used in one cell can be reused
Prof. Z. Ghssemlooy
in another cell some distance away
21. Mobile Communications - Principlesp
Wave propagation mechanism is closely affected by the
wavelengths of the propagating frequency
Uses a separate radio channel to talk to the cell site
C ll it t lk t bil t iCell site talks to many mobiles at once, using one
channel per mobile
Channels use a pair of frequencies for:
• forward link for transmitting from the cell site
li k f th ll it t i ll f th• reverse link for the cell site to receive calls from the users
Radio energy dissipates over distance so mobiles mustRadio energy dissipates over distance, so mobiles must
stay near the base station to maintain communications
Basic structure of mobile networks includes telephone
Prof. Z. Ghssemlooy
p
systems and radio services
22. Mobile Communs. - Cellular Spectrum
Phone Transmit
A band
10 MHz
B band
10 MHz
825 835 845824 846.5 849
A”b
A’b
B’b
333 channels
30kHz
333 channels
30kHz
band
and
and
1 MHz 1.5 MHz 2.5 MHz
33 chs 50 chan 83 chs
20 MHz Guard
870 880 890869
A band B band
Base Transmit
891.5 894
A
A band
10 MHz
333 channels
30kHz
B band
10 MHz
333 channels
30kHz
A”band
A’band
B’band
Prof. Z. Ghssemlooy
1 MHz
33 chan
1.5 MHz
50 chs
2.5 MHz
83 chs
23. Mobile Comms. - Systemy
• Mobile Unit
• Mobile Base Station
• Mobile Switching Centre
Prof. Z. Ghssemlooy
Mobile telecommunications
switching office (MTSO)
24. Mobile Comms. - Componentsp
Mobile Base Station (MBS): includesMobile Base Station (MBS): – includes
– an antenna,
– a controller,a controller,
– a number of receivers
Mobile telecommunications switching office (MTSO)
– connects calls between mobile units
Channels between mobile unit and MBS
C t l h l t h i f ti l t d t tti– Control channels: to exchange information related to setting up
and maintaining calls
– Traffic channels: to carry voice or data connection betweeny
users
Prof. Z. Ghssemlooy
25. MTSO Controlled Call between Mobile
UsersUsers
Steps:-Steps:-
Mobile unit initialization
Mobile originated callMobile-originated call
Paging
C ll t dCall accepted
Ongoing call
H d ff
Functions:-
Handoff Call blocking
Call termination
Call dropping
Calls to/from fixed and remote
Prof. Z. Ghssemlooy
mobile subscriber
26. Mobile Radio Environment
P ti P th LPropagation Path Loss
Multipath Fading
Frequency-Selective Fading
Doppler Shiftpp
Co-Channel Interference
Adjacent Channel InterferenceAdjacent Channel Interference
Man-Made Noise
Urban EnvironmentUrban Environment
Suburban Environment
R l E i t
Prof. Z. Ghssemlooy
Rural Environment
27. System Characteristicsy
Frequency sharing amongst users
M lti th i t f i tMultipath interference environment
Line-of sight coverage (UHF)
High base station antenna (30m)
Low mobile antenna (1 5m - 3m)Low mobile antenna (1.5m - 3m)
Beyond Line-of-sight (VHF)
Long distance (HF)
Prof. Z. Ghssemlooy
28. Early Mobile Systemsy y
Traditional mobile similar to TV broadcastingTraditional mobile similar to TV broadcasting
One very powerful transmittery p
located at the highest spot
would cover an area with a
di f t 50 kradius of up to 50 km
Cellular concept re-structured the mobile telephone
network in a different way:network in a different way:
• Using low power transmitters to cover larger area.
E g dividing a metropolitan region into 100 different cells
Prof. Z. Ghssemlooy
E.g. dividing a metropolitan region into 100 different cells
12 channels each
29. Digital Cellular- what does it offers?g
Best quality compared with analogue system
Improved bandwidth efficiencyImproved bandwidth efficiency
- Reduced from 30 kHz to 10 kHz, and then to 5 kHz.
This is achieved via 3-time-slot Time Division Multiple Access
(TDMA) (i.e. three pairs of people using a 30 kHz radio
channel simultaneously)
Use of micro-cellular technology to accommodate smaller and
smaller cells particularly around the new frequency band
f 2 GHof 2 GHz
Improved frequency reuse
Prof. Z. Ghssemlooy
Improved frequency reuse
31. Transmission Types - Full Duplexyp p
f1 f3
f f
Tx : f1
R f
Tx : f3
R f
f4f3f2f1
f2 f4
Rx : f2 Rx : f4
RxTx
TxRx
Prof. Z. Ghssemlooy
32. Transmission - Duplex Operationp p
f1 f2
RxRx
((ff )) Antenna
f1 f2
F((ff11))
DupDup
AntennaF1
TxTx
((ff ))
MM
f2
((ff22))
T
Load
Tx LoadReception
Tx
Load
Prof. Z. Ghssemlooy
Rx
Antenna Transmission RxAntenna
33. Typical Wide-Area Systemyp y
DispatcherDispatcher
Di it l
Dispatcher
2
Digital
Switch
DispatcherDispatcher
11
-- Dispatcher: Communicates with the vehicles.Dispatcher: Communicates with the vehicles.
C i ti d H lf D lC i ti d H lf D l
Prof. Z. Ghssemlooy
-- Communication mode: Half Duplex.Communication mode: Half Duplex.
-- MobileMobile--toto--mobile communication is possible using a Talkmobile communication is possible using a Talk--Through Repeater (halfThrough Repeater (half--duplex) orduplex) or
direct using Simplex mode.direct using Simplex mode.
34. Mobile Transmission Environment
Deep Radio Shadow + Radio HorizonDeep Radio Shadow + Radio Horizon
Reflection, Refraction and Scattering
FadingFading
– Frequency-Selective
– Multipath
Propagation Path Loss (Attenuation)
Doppler Shift
Delay Distortiony
Noise and Interference
Urban Suburban and Rural Environments
Prof. Z. Ghssemlooy
Urban, Suburban, and Rural Environments
35. Transm. Pro. - Deep Radio Shadowp
Radio waves at low frequencies can diffract (bend) around object quit• Radio waves at low frequencies can diffract (bend) around object quit
well
• In mobile systems (high frequency band), wave diffraction does not
take place well, therefore a deep radio shadow occurs on the un-
illuminated side of the obstruction (e.g., building, hill, truck, or even
human being)
shadow
human being)
shadow
T
Prof. Z. Ghssemlooy
Tx
36. Transm. Env. - Radio Horizon (1/2)
• Is 30% farther from the transmitting antenna than the
equivalent visible horizon due to the reduction of the
refraction in the upper atmosphere as compared to that
t d l lat ground level.
Beyond radio horizon the signal strength falls very rapidlyBeyond radio horizon, the signal strength falls very rapidly
so that in areas well beyond the horizon the same frequency
can be reused without causing interference.g
• The higher the transmitter antenna the further away isThe higher the transmitter antenna, the further away is
its radio horizon.
Prof. Z. Ghssemlooy
37. Transm. Env. - Radio Horizon (2/2)
The coverage area (not the radius) is approximately
proportional to the antenna heights of both transmitter
and receiverand receiver.
With a higher transmitter tower the far flung horizonWith a higher transmitter tower, the far flung horizon
prevents close reuse of the same frequency.
Between the transmitter and horizon in open flatBetween the transmitter and horizon, in open, flat
country, the received power reduces approximately
as the inverse fourth power of distance from the
transmitter (as we see later on).
Prof. Z. Ghssemlooy
38. Transmission Env. – contd.
Ei
Reflection at large obstacles
i
Er= α Ei, where α is the absorption coefficient < 1
Ei
Scattering at small obstacles Er1= α Ei
E 2= α EiEr2 α Ei
Erk= α Ei
E 1= α E
Diffraction at edges
Ei
Er1 α Ei
Er2= α Ei
Prof. Z. Ghssemlooy
Diffraction at edges
39. Transm Env – MultipathTransm. Env. – Multipath
Dispersion
signal at Tx
Dispersion
Distortion
signal at Tx
signal at receiver
Dispersion: signal is dispersed over time, thus interfering with
“neighbor” symbols --> Inter Symbol Interference
Distortion: signal reaches a receiver directly and phase
shifted:- distorted signal depending on the phases of the
different parts
Prof. Z. Ghssemlooy
different parts
40. Transm. Pro. – Multipath Fadingp g
In a multipath propagation environment signal are:In a multipath propagation environment signal are:
- Generally added to strengthen the received signal
- At some point they subtract from one another, thus causing
fading, (at approximately half wavelength intervals).
- The fade power level is typically 20 dB weaker than the local
average field strength. Fades that are 40 dB weaker are not
uncommon.
- The combination of shadowing and multipath fading results
in a radio field that varies wildly over a short ranges (up to
60 or 70 dB difference between the maximum and minimum
t t l l l ithi 100 2)
Prof. Z. Ghssemlooy
street level value within a 100 m2).
41. Transm. Env. - Attenuation
• The strength (amplitude) of the signals reduces as it• The strength (amplitude) of the signals reduces as it
propagate through the channel. This is called signal
attenuation or loss, which is due to:,
• Absorption of energy
• Scattering of energy
• Limits the maximum coverage distance.
• Can be overcome by in line amplification.Can be overcome by in line amplification.
High frequencies penetrates building fairly well, mostly
th h d i d d thi t lli f
High frequencies penetrates building fairly well, mostly
th h d i d d thi t lli fthrough doors, windows, and thin non-metallic roofs.
Typical mean building penetration losses are 10 to 20
dB, but penetration losses as high as 40 dB have been
through doors, windows, and thin non-metallic roofs.
Typical mean building penetration losses are 10 to 20
dB, but penetration losses as high as 40 dB have been
Prof. Z. Ghssemlooy
dB, but penetration losses as high as 40 dB have been
encountered.
dB, but penetration losses as high as 40 dB have been
encountered.
42. Transm. Env. - Bandwidth
• All real channels have a limited bandwidthAll real channels have a limited bandwidth.
• Not all the frequency components of transmitted signal
will pass through the channel.
• At the receiver, exact regeneration of the original signalAt the receiver, exact regeneration of the original signal
becomes quite difficult.
• Resulting in the received signal distortion• Resulting in the received signal distortion
Prof. Z. Ghssemlooy
43. Transm. Pro. - Delay Distortiony
• Critical in complex waveform transmission, such as Digital
Signals, where different frequency components of the
same signal travel at slightly different speedssame signal travel at slightly different speeds.
• As the propagation link increases, fast components of one
bit (edges) may eventually catch up the proceeding slow( g ) y y p p g
moving components of the bit (flat top). Thus resulting in
distortion.
Prof. Z. Ghssemlooy
44. Transm. Pro. - Noise & Interference
. Thermal noise
. Amplifier noise
RF
RF + NoiseReceiverReceiver
RF
signal
. Man made noise
. Inter-modulation: noise from other transmitters at different
frequencies
. Co-channel interference: noise from other transmitter at the same
frequency
Prof. Z. Ghssemlooy
frequency
. Electromagnetic interference in a vehicle
45. Mobile Phones Technology -
DisadvantagesDisadvantages
Although the development of mobile phones brought convenient andAlthough the development of mobile phones brought convenient and
advantages to the world. But the disadvantages brought along with
the fast grown technology cannot be ignored. These problems not
only influenced people personally but also the society at largeonly influenced people personally but also the society at large.
Symptoms caused by the radiation of mobile phones are:
– headache, earaches, blurring of vision and even causing cancer
Though, these problems are still under research. Mobile phone
users are advice to reduce the usage on mobile phones if it is
possible.p
Mobile phone addiction.
– Mobile phone addiction is becoming one of the biggest non-drug
addictions in the 21st century in particular among the teenagersaddictions in the 21st century in particular among the teenagers.
– New models of mobile phones are released almost everyday. In order
to get up-to-date, people tend to change their mobile phones once in
a while These became habits among the mobile phone users causing
Prof. Z. Ghssemlooy
a while. These became habits among the mobile phone users causing
them to spend unnecessary cost on mobile bills and
46. Mobile Phone Technology - Future
DevelopmentDevelopment
Mobile phones are getting more and more sophisticatedMobile phones are getting more and more sophisticated,
just like computer
The technology is growing everyday with different functions
and usage
From the network system from mobile phones, it is still
developingdeveloping.
– The new 3G system had just been launched not long ago,
– 4G system expected in 2010. It is expected that the 4G
system will be able to deliver
• a much faster speed up to 100Mb per second during connection,
• tighter network security
• High quality during communication no matter on voice or video calls.
• security system, and surveillance on certain items. The 4G system will be
expected to be launched in 2010.
Prof. Z. Ghssemlooy
47. Mobile Phone Technology - Future
DevelopmentDevelopment
Mobile phone, the piece of communication device
itself is also becoming a multi functioned device.
S t h d PDA h l dSmartphones and PDA phones are already
launched in the market.
M bil h ith ti f ti l iMobile phone with computing functions replacing
lap-tops
Prof. Z. Ghssemlooy