Existing Wireless System
Azizol Bin Abdullah
azizol@fsktm.upm.edu.my (A2.04)
Rujukan: Text Book Chapter 10
Existing Wireless Systems
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Wireless system needs to take many factors into
account:
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Call rate
Call duration
Distribution of MSs
Traffic in an adjacent cell
The terrain
Atmospheric conditions
In the real world, there are various characteristic of
existing cellular system and how they support
seamless mobile communication
Existing Wireless Systems(cont.)
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The important to emphasize in communication
system where the receiver gets the information
from the sender successfully by following a set of
rules call communication protocol.
The protocol in a wireless environment also follow
similar steps in OSI model, except a few steps are
not used for the sake of efficiency.
Some layers may be subdivided into a number of
successive operations.
Existing Wireless Systems(cont.)
1st Generation
2G
2.5G
CDMA, IS95
Verizon, Sprint
AMPS
NMT, TACS
CDMA-2000
1XRTT
TDMA, IS136
AT&T
GSM, 1900 MHz
Voicestream
GSM Europe
900/1800 MHz
Wireless Systems
3G
CDMA 2000
EV-DO
EV-DV
EDGE?
GSM, 1900/800 MHz
AT&T, Cingular
WCDMA
GPRS
WiFi - 802.11
Bluetooth
Advanced Mobile Phone
Systems(AMPS)
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AMPS – first-generation cellular used in US.
Transmit speech signal employing FM and control
information transmitted in digital using FSK
Create by AT&T Bell labs with the idea of dividing
the entire service area into logical divisions called
cell.
Cell radius 1 to 16 miles. Larger cell tends to have
more thermal noise and less interference, while
smaller cells have more interference and less
thermal noise.
Allow both cell sectoring and cell spliting.
Advanced Mobile Phone
Systems(AMPS) (cont.)
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Have low-power MS with 4 Watts or less
and medium-power BS with 100 Watts.
Capable to support about 100,000 users per
city.
AMPS : Characteristic
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Uses frequency band from 824 MHz to 849 MHz
for transmission from MSs to BS(uplink) and 869
MHz to 894 MHz from BS to MSs(downlink)
3 KHz analog voice signal modulated onto 30 KHz
channel using Manchester frequency modulation at
rate 10 kbps
One control transreceiver for every eight voice
transreceiver.
Frequency allocation done by dividing the entire
frequency spectrum into two bands – Band A and
Band B.
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Non wireline provider are given Band A and
wireline provider are given Band B : a total
666 channels.
AMPS uses directional radio propagation
enables different frequencies to be
transmitted in different direction – reducing
radio interference.
TACS – Total Access Communication
System
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variant of AMPS
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deployed in a number of countries
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primarily in the UK
NMT – Nordic Mobile Telephone
System
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analog technology
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deployed in the Benelux countries and Russia
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operates in the 450 and 900 MHz band
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first technology to offer international roaming
– only within the Nordic countries
Global System for Mobile Communication
(GSM) : Introduction
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Early 80’s Europe was experiencing rapid growth in
the analog cellular telephone systems
1982 Conference of European Posts and Telegraphs
(CEPT) GSM (Groupe Special Mobile) group was
formed to study and develop a pan-European
public land mobile system
GSM mandate was to develop a standard to be
common for the countries that created it – provide
service to the entire European continent
Global System for Mobile Communication
(GSM) : Introduction. (cont.)
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GSM criteria –
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Good subjective speech quality
Low terminal and service cost
Support for international roaming – one system for all of
Europe
Ability to support handheld terminals
Support for range of new services and facilities
Enhanced Features
ISDN compatibility
Enhance privacy
Security against fraud
Global System for Mobile Communication
(GSM) : Introduction. (cont.)
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Phase I of GSM specifications was published in 1990
International demand was so great that the system name
was changed from Groupe Special Mobile to Global Systems
for Mobile Communications (still GSM)
Commercial service started in mid-1991
1992 first paying customers were signed up for service
By 1993 there were 36 GSM networks in 22 countries
Early 1994 there were 1.3 million subscribers worldwide
By 1996 there were more than 25 million subscribers
worldwide
By October 1997 it had grown to more than 55 million
subscribers worldwide
GSM : System Architecture
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Mobile Station (MS)
Mobile Equipment (ME)
Subscriber Identity Module (SIM)
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Base Station Subsystem (BBS)
Base Transceiver Station (BTS)
Base Station Controller (BSC)
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Network Subsystem
Mobile Switching Center (MSC)
Home Location Register (HLR)
Visitor Location Register (VLR)
Authentication Center (AUC)
Equipment Identity Register (EIR)
GSM : System Architecture (cont.)
GSM : System Architecture (cont.)
The Mobile Station is made up of two entities:
1. Mobile Equipment (ME)
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Produced by many different manufacturers
Must obtain approval from the standardization body
Uniquely identified by an IMEI (International Mobile
Equipment Identity)
2. Subscriber Identity Module (SIM)
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Smart card containing the International Mobile Subscriber
Identity (IMSI)
Allows user to send and receive calls and receive other
subscribed services
Encoded network identification details
Protected by a password or PIN
Can be moved from phone to phone – contains key
information to activate the phone
GSM : System Architecture (cont.)
Base Station Subsystem is composed of two parts
that communicate across the standardized Abis
interface allowing operation between components
made by different suppliers
1.
Base Transceiver Station (BTS)
2.
Base Station Controller (BSC)
GSM : System Architecture (cont.)
Base Transceiver Station (BTS)
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Houses the radio transceivers that define a cell
Handles radio-link protocols with the Mobile Station
Speech and data transmissions from the MS are
recoded
Requirements for BTS:
reliability
portability
minimum costs
GSM : System Architecture (cont.)
Base Station Controller (BSC)
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Manages Resources for BTS
Handles call set up
Location update
Handover for each MS
GSM : System Architecture (cont.)
Mobile Switching Center (MSC)
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Switch speech and data connections between:
Base Station Controllers
Mobile Switching Centers
GSM-networks
Other external networks
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Heart of the network
Three main jobs:
1) connects calls from sender to receiver
2) collects details of the calls made and received
3) supervises operation of the rest of the network components
GSM : System Architecture (cont.)
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Home Location Registers (HLR)
- contains administrative information of each subscriber
- current location of the mobile
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Visitor Location Registers (VLR)
- contains selected administrative information from the HLR
- authenticates the user
- tracks which customers have the phone on and ready to receive
a call
- periodically updates the database on which phones are turned
on and ready to receive calls
GSM : System Architecture (cont.)
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Authentication Center (AUC)
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mainly used for security
data storage location and functional part of the network
Ki is the primary element
Equipment Identity Register (EIR)
- Database that is used to track handsets using the IMEI
(International Mobile Equipment Identity)
- Made up of three sub-classes: The White List, The Black List
and the Gray List
- Optional database
GSM : Features
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Call Waiting
- Notification of an incoming call while on the handset
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Call Hold
- Put a caller on hold to take another call
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Call Barring
- All calls, outgoing calls, or incoming calls
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Call Forwarding
- Calls can be sent to various numbers defined by the user
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Multi Party Call Conferencing
- Link multiple calls together
GSM : Advance Features
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Calling Line ID
- incoming telephone number displayed
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Alternate Line Service
- one for personal calls
- one for business calls
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Closed User Group
- call by dialing last for numbers
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Advice of Charge
- tally of actual costs of phone calls
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Fax & Data
- Virtual Office / Professional Office
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Roaming
- services and features can follow customer from market to market
GSM: Advantages
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Crisper, cleaner quieter calls
Security against fraud and eavesdropping
International roaming capability in over 100 countries
Improved battery life
Efficient network design for less expensive system expansion
Efficient use of spectrum
Advanced features such as short messaging and caller ID
A wide variety of handsets and accessories
High stability mobile fax and data at up to 9600 baud
Ease of use with over the air activation, and all account information is
held in a smart card which can be moved from handset to handset
GSM : Frequency Band and Channels
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Allocated an operational frequency from 890
MHz to 960 MHz.
To reduce interference – MS and BS used
different frequency range
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MSs : 890 MHz to 915 MHz
BS : 935 MHz to 960 MHz
GSM follows FDMA and allows up to 124 MSs
to be serviced at the same time.
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25 MHz frequency is divided into 124 FDM
channels( each 200 kHz, guard frame 8.25 bits)
GSM : Frequency Band and Channels
(cont.)
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Uses a variety of control channels – ensure
uninterrupted communication between MSs and BS.
Three control channels used for broadcasting info to
all MSs:
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Broadcast Control Channel (BCCH) : transmitting system
parameters – frequency of operation in the cell and operator
identifiers
Frequency Correction Channel (FCCH) : transmitting
frequency references & frequency correction burst at 148
bits length
Synchronization Channel (SCH) : provide the synchronization
training sequences burst of 64 bits length to MSs
GSM : Frequency Band and Channels
(cont.)
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Three control channels used for establishing
links and ongoing call management:
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Random Access Channel (RACH) : used by the MS
to transmit information regarding the requested
dedicated channel from GSM.
Paging Channel : used by the BS to communicate
with individual MSs in the cell.
Access Grant Channel : Used by the BS to send
information about timing and synhronization
GSM : Frequency Band and Channels
(cont.)
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Dedicated control channels used along with traffic
channels to serve for any control information
transmission during the actual communication:
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Slow Associated Control Channel (SACCH): Allocated along
with a user channel, for transmission of control information
during the actual transmission.
Stand-alone Dedicated Control Channel (SDCCH): Allocated
with SACCH – used to transfer of signaling information
between BS and MSs – part of control channel.
Fast Associated Control Channel (FACCH): carries the same
information as SDCCH - part of traffic channel. Facilitate
FACCH to steak certain bursts from the traffic channels –flag
bits (two bits) in the message.
Personal Communication Services
(PCS)
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Employs an inexpensive, lightweight and portable handset to
communicate with a PCS BS.
PCS encompasses the whole spectrum of communication
services : an ordinary telephone to cable television.
PCS can be classified into: high-tier and low-tier standards.
Higher-tier systems include high-mobility units with large
batteries.
Low-tier systems include systems with low mobility, capable of
providing high-quality portable communication services over a
wide area.
PCS low-tier standards based on PACS (Personal Access
Communication System) and DECT (Digital European Cordless
Telecommunications)
PCS : Chronology of PCS
Development
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Start with CT2 – cordless telephone
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Operates using FDMA with the speech rate of 32 kbps
using Adaptive Differential Pulse Code Modulation
(ADPCM).
Transmitter data rate 72 kbps
Uses TDD, allows BS and MS to share one channel
DECT
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2nd generation cordless telephone system.
Operates on frequencies ranging from 1880 MHz to
1900 MHz
Uses ADPCM with 32 kbps
Uses TDD with 2 frames (BS-MS, MS-BS) 10-ms period
PCS : Bellcore view of PCS
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Based on 5 different access services between BCC(
Bellcore client company), BCC network and PCS
wireless provider:
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PCS access services for network (PASN) – connection to and
from PCS service provider.
PCS access service for controller (PASC) – uses across radio
channel and automatic link transfer capability
PCS access service for ports (PASP) – interface to PCS
wireless provider
PCS access service for Data (PASD) – database information
transport service
PCS access service for external service provider (PASE) –
support specialized service like voice mail and paging.
IS-95
- Interim Standard 95 (IS-95), is the first CDMA-based
digital cellular standard pioneered by Qualcomm(wireless
telecommunication R&D company based in USA)
- Its brand name is cdmaOne and the initial specification for the
system was IS95A, but its performance was later upgraded
under IS-95B.
-Apart from voice the mobile phone system is also able to carry
data at rates up to 14.4 kbps for IS-95A and 115 kbps for IS95B.
IS-95 (cont.)
- Qualcomm had been investigating the use of direct
sequence spread spectrum techniques for military use
when it was realised that it could be used as a multiple
access technology for mobile communications.
- It is now being supplanted by IS-2000 or better known as
cdma2000.
IS-136
- The name "TDMA" is used to refer to a specific second
generation mobile phone standard - more properly referred
to as IS-136, which uses the TDMA technique to timeshare
the bandwidth of the carrier wave. It provides between 3 to
6 times the capacity of its predecessor AMPS, and also
improved security and privacy.
- In the United States, for example, AT&T Wireless uses
the IS-136 TDMA standard. Prior to the introduction of
IS-136, there was another TDMA North American digital
cellular standard called IS-54(which was also referred to
just as "TDMA").
GPRS
 a radio technology for GSM networks that adds packet-switching protocols,
shorter set-up time for ISP connections, and offer the possibility to charge by
amount of data sent rather than connect time.
GPRS promises to support flexible data transmission rates typically up to 20 or 30
Kbps (with a theoretical maximum of 171.2 Kbps), as well as continuous
connection to the network.
A 2.5G enhancement to GSM, GPRS is the most significant step towards 3G,
needing similar business model, and service and network architectures.
GPRS started to appear in some networks during 2000.
EDGE
-Enhanced Data Rates for GSM Evolution:
An enhanced modulation technique designed to increase
network capacity and data rates in GSM networks.
-EDGE should provide data rates up to 384 Kbps. EDGE
will let operators without a 3G license to compete with 3G
networks offering similar data services.
IMT2000
-IMT-2000 (International Mobile Telecommunications-2000) is the
standards for the "third generation" (3G) mobile phone services
which enables high speed, high quality multi-media voice and data
transmission through cellular phone system.
(a generic way to describe third-generation cellular phone services
that offer high-speed Internet access.)
-It enables global service
-IMT-2000 uses a 2 GHz frequency band which is allocated to all
the countries. Thus it enable the global service of high speed
communications interoperable in all countries.
IMT2000(cont)
-ITU approved 5 terresterial and 6 satellite based systems
-Various new standards have been proposed and alliances
formed to promote 3G wireless standards.
-Japan and Europe jointly proposed Wideband CDMA (or W-CDMA)
standard,and U.S. proposed CDMA2000 and many others.
-In November 1999, ITU-R SG8 approved 5 terresterial
systems (including W-CDMA and CDMA2000) and 6 satellite-based
systems for IMT-2000.
UMTS
UMTS (Universal Mobile Telecommunications System) is the European vision
of a third generation mobile communication system. It is designed to continue
the global success of the European second generation mobile communication
system GSM (Global System for Mobile communication) which had, in
December 1998, about 100 million customers and 300 operators worldwide.
-3GPP developed the specification for UMTS. The 3rd Generation Partnership
Project (3GPP) is a collaboration agreement that was established in December
1998
UMTS (cont)
Network Development:
The development of UMTS has got two aspects, the radio access network and
the core network. The radio access network comprises the mobile station
(handy), the base station (transceiver, antenna, controller) and the radio
interface between them. The core network consists of nodes (switches) with
connecting lines. This core network does not only connect the base stations
with each other but offers also gateways to other networks (ISDN, Internet,..)
The core network of UMTS is an evolution of the present GSM-core network.
The radio access network of UMTS, especially the method of radio
transmission (radio interface), is revolutionary new.
The UMTS radio access network URAN will not be an evolution of the GSM
radio access network. However, the GSM radio access network will be in use
and also under development even after the introduction of UMTS. This means
that there will be a common core network but two independent radio access
networks for UMTS and for GSM. The UMTS radio access network will allow for
multimedia applications because of the larger bandwidth of the radio channels
(5 MHz instead of 200 kHz in GSM) and the new access method CDMA (Code
division multiple access).
UMTS (cont)
Network development(cont)
Multimedia in UMTS means that the simultaneous transfer of speech, data, text,
pictures, audio and video with a maximum data rate of 2 Mbit/s will be possible.
Transmission of speech and low data rate applications will go on to be carried
out by GSM (lower price); at least during the first years after the introduction of
UMTS around 2002.
UMTS (cont)
Hierarchical cell structure
UMTS will offer global radio coverage and
world-wide roaming. For that purpose the
URAN will be built in a hierarchical way in
layers of varying coverage. A higher layer
will cover a larger geographical area than
a lower layer. In the highest layer there
will be satellites covering the whole
planet, the lower layers form the UMTS
terrestrial radio access network UTRAN.
fig. 1:
Hierarchical cell structure of UMTS to offer global radio coverage
They are divided into macro-, micro- and picolayer. Each layer is divided into cells. The lower the
hierarchical level, the smaller the cells. Smaller cells allow for a higher user-density. Therefore
macrocells are used for land-wide coverage, additional microcells are installed in areas with higer
population density and picocells in buildings and for so called "hot spots" (e.g. airports, railway
stations).
UMTS (cont)
Data rate
The maximum data rate and the maximum
speed of the user are different in each
hierarchical layer. In the macrolayer at least
144 kbit/s with maximum speed of 500 km/h
shall be possible. In the microlayer 384 kbit/s
with maximum speed of 120 km/h shall be
supported. The picolayer offers up to 2 Mbit/s
with a maximum speed of 10 km/h.
fig. 2:
Data rate versus mobility for UMTS in comparison with fixed network and other mobile
communications systems (WLAN Wireless Local Area Network, MBS Mobile Broadband Systems)
It shall be possible for the user to trade off bit error rate versus delay in certain limits. For real-time
applications with constant delay (speech, video) the bit error rate can be in the range of 10-3 to 10-7,
the maximum delay can be in the range of 20 ms to 300 ms. For non-realtime applications (e-mail,
SMS) with variable delay the bit error rate can be in the range of 10-5 and 10-8. The maximum delay
can be 150 ms and more.
UMTS (cont)
Spectrum
The spectrum for
UMTS lies between
1900 MHz to 2025 MHz
and 2110 MHz to 2200
MHz. For the satellite
service an own
subband in the UMTS
spectrum is reserved
(uplink 1980 MHz to
2010 MHz, downlink
2170 MHz to 2200
MHz).
fig.
3:
Spectrum for UMTS -
1920 MHz - 1980 MHz
FDD Uplink
2110 MHz - 2170 MHz
FDD Downlink
1900 MHz - 1920 MHz
2010 MHz - 2025 MHz
TDD
1980 MHz - 2010 MHz
MSS (Mobile Satellite Service) Uplink
2170 MHz - 2200 MHz
MSS Downlink
The remaining spectrum for terrestrial use is divided between two modes of operation. In the
FDD (Frequency Division Duplex) mode there are two equal bands for the uplink (1920 MHz to
1980 MHz) and for the downlink (2110 MHz to 2170 MHz). In the operation mode TDD (Time
division duplex) uplink and downlink are not divided by use of different frequency carriers but
by using different timeslots on the same carrier. So there is no need for a symmetrical
spectrum but the remaining unpaired spectrum can be used.
cdma2000
- CDMA2000 - A third-generation wireless technology proposal
submitted to the International Telecommunication Union, which
is based on the IS-95, or cdmaOne, standard.
-CDMA2000 specification was developed by the Third Generation
Partnership Project 2 (3G PP2), a partnership consisting of five
telecommunications standards bodies: ARIB and TTC in Japan,
CWTS in China, TTA in Korea and TIA in North America.
-Cdma2000 has already been implemented to several networks
as an evolutionary step from cdmaOne.
cdma2000 (cont.)
- The first 3G networks to be commercially deployed
were launched in Korea in October 2000 using
CDMA2000 technology.
- CDMA2000 dominates the 3G market today and
analysts forecast that it will continue to lead in the
future.
cdma2000 (cont.)
CDMA2000
CDMA2000 1X
CDMA2000 1xEV-DO
CDMA2000 1xEV-DV
CDMA2000 3X
Common name for IMT-2000 CDMA Multi-Carrier.
The first step in the evolution to 3G is cdma2000 1X, which improves packet
data transmission capabilities and speeds in the network, and also boosts
voice capacity by nearly two times over today's CDMA capacities. Speed of
upto 144kpps.
(Evolution Data-Only). CDMA2000 1XEV represents the second step in the
evolution of CDMA2000. Commercially launched in 2001, offers data speeds of
up to 2.4 Mbps on a separate 1.25 MHz carrier.
(Evolution Data-Voice). CDMA2000 1XEV represents the second step in the
evolution of CDMA2000. Recently approved by ITU as a 3G technology, will
provide data and voice together on a single 1.25 MHz channel, with data rates
of up to 4.8 Mbps.
3G technology which offers voice and data on a 5MHz carrier (or 3 times [3X]
the 1.25 MHz carrier). Full 3G version of CDMA2000. Technology is similar to
CDMA2000 1x, but the peak data rate is 2Mbps.
Migration Paths to 3G
(USA Environment)
1G
2G
2.5G
3G
IS-54
IS-136
EDGE
3G
AMPS
IS-95
cdma2000 1x
cdma2000 3x
NOTE:
IS-54:the GSM TDMA
IS-136: the D-AMPS(different TDMA)
IS-95: the cdmaOne
The version of this CDMA is incompatible with the one used in Europe, known
as WCDMA!!!
Migration Paths to 3G
(Europe Environment)
1G
2G
2.5G
GSM
GPRS
3G
NMT
(Scandinavia)
EDGE
UMTS
TACS
(England)
UMTS: Universal Mobile Telecommunications Systems, the “official” 3G
system for Europe. UMTS is a true packet switched network(no more
overlay). However, it works at different frequency(2000 MHz) than both 1G
and 2G, thus major upgrade required. UMTS is not based on TDMA like
GSM but on CDMA called the Wideband CDMA/WCDMA.
Migration Paths to 3G
(Japan Environment)
1G
JTACS
2G
PDC
3G
WCDMA
PDC is based on TDMA air interface. Because of all this uniformity, it was
possible for Japan to jump over 2.5G and go right to 3G system. As a result,
Japan is the 1st country to deploy a system with 3G capabilities. The system
is based on a WCDMA air interface similar to that in UMTS.
Migration Paths to 3G
(Summary)
IS-54
IS-136
EDGE
3G
AMPS
IS-95
cdma2000 1x
cdma2000 3x
NMT
(Scandinavia)
GSM
EDGE
GPRS
TACS
(England)
JTACS
PDC
WCDMA
UMTS
Summary
Worldwide Systems
Acronym
System
Where First
Deployed
Technology
AMPS
Advanced Mobile Phone
Service
USA
Analog
CDMA
Code Division Multiple
Access
USA
Digital
D-AMPS
Digital Advanced Mobile
Phone Service
USA
Digital
DCS1800
Digital Communication
Service
Germany &
England
Digital
GSM
Group Special Mobile
80 European
countries
Digital
JTACS
Japan Total Access
Communication System
Japan
Analog
Worldwide Systems(cont)
Acronym
System
Where First
Deployed
USA
Technology
NADC
North American Digital
Cellular
NMT
Nordic Mobile Telephone Scandinavian
countries
Analog
PCS1900
Personal
USA
Communication Services
Digital
PDC
Personal Digital Cellular
Digital
SMR
Specialized Mobile Radio USA
Both
TACS
Total Access
England
Communications System
Analog
Japan
Digital
Characteristics of Various
Cellular Generations
1G
Signal
Type
2G
2.5G
3G
Analog
Digital
Digital
Digital
Switching Circuit
Circuit
Packet
Packet
Offerings
Messaging
Internet
Multimedia
14 Kbps
144 Kbps
384 Kbps –
2Mbps
Data Rate
Voice
-
First Generation
-started appearing in the 1980s
-1G networks are based on the AMPS (Advanced Mobile
Phone Service) standard
-1G introduced the idea of cells
-analog (varying waveform in sending info) and not digital
-only to be used for voice communication; no data service
-quality was not that good(a lot of interference)
First Generation (cont.)
disadvantages:
a) insecure
i) one can snoop into other people’s conversation
ii) can charge calls to another person’s account
b) Handsets had short talk/standby times
Second Generation
-converts all voice communication into digital ( 0 and 1
only)
-there are several 2G standards in use:
i) TDMA (Time Division Multiple Access). Used primarily
in the USA.
ii)GSM (Global System for Mobile Communications).
Widely used in Europe and countries other than USA,
now appearing in the USA.
Second Generation (cont.)
iii)CDMA (Code Division Multiple Access). Used in
USA and its use is spreading in the rest of the
world.
iv)PDC (Personal Digital Cellular). Used only in
Japan where iMode uses packet switched PDC.
Second Generation (cont)
-some characteristics of 2G networks are:
#Maximum data rates of 9.6 to 14.4 Kbits/second
#Digital voice(results in a lower quality voice but uses less
precious spectrum)
#Enhanced telephony features such as caller-id.
#Services such as text based messaging (big winner),
downloads of still images and audio clips, etc.
#Much secure; encryption
2.5 Generation
- are essentially General Packet Radio Service (GPRS)
packet overlays on 2G networks. Besides enhancing GSM and
TDMA networks by making them packet-based networks, it also
increases their data rates.
-it is primarily a software upgrade of GSM.
-some characteristics of 2.5G networks are:
#Data rates of 64 - 144kb/second.
#Packet based.
#Always-on connectivity.
#Instant messaging with small attachments.
2.5 Generation (cont)
-A new wireless standard, Enhanced Data GSM Environment
(EDGE), has been developed to increase the bandwidth of
GPRS.
-EDGE triples the bandwidth capacity of GPRS to 384
Kbits/second thus allowing GSM and TDMA operators to
offer high-speed services. EDGE based networks fall in
between 2.5G and 3G networks. (http://www.silicon-press.com)
Third Generation
-3G provides high speed bandwidth (high data transfer rates)
to handheld devices.
-Specifically, 3G wireless networks support the following
maximum data transfer rates:
2.05 Mbits/second to stationary devices.
384 Kbits/second for slowly moving devices, such as a
handset carried by a walking user.
128 Kbits/second for fast moving devices, such as handsets
in moving vehicles.
Third Generation (cont.)
- It is expected that 3G will be able to offer a variety
of new services that combine high voice quality
telephony, high-speed Mobile IP services,
information technology, rich media, and
offer diverse content.
Fourth Generation
-4G networks are already in the labs, targeted for deployment
beginning in 2010
-will provide up to 100 Mbps
-one possible application for such high data rates is
telepresence (a virtual reality: full stimulation of all senses
required to provide the illusion of actually being somewhere
else AKA an illusion that cannot be distinguished from the
real thing!!)
(Referance: Andy Dornan, The Essential Guide to Wireless Communications
Applications, Prentice Hall 2001)
Fourth Generation
Fourth Generation
Fourth Generation
“Killer” Applications
-Two 2G wireless data applications have turned out to be big
winners:
a) iMode (Japan): Downloading of images to mobile phones
and forwarding them to other mobile phones.
b)GSM (Europe and countries other than USA): Sending
short text messages from one mobile phone to another
using the Short Message Service (SMS)