12Evolution of Cellula(1)

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3G and Beyond


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Integration of voice and data traffic

Multimedia applications require both voice and

data.

The main feature of 3G cell phone systems is to

handle both voice and data so users can accessthe Internet and e-mail, listen to music, watch

movies, use navigation, etc.

Data oriented systems, e.g., 802.11 need to

handle voice, too, due to the use of Voice over

IP.


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Drawbacks of voice oriented systems

unused capacity

In TDMA/FDMA, a number of channels areassigned to a cell. When the number ofactive users falls below the available

number of channels, some portion of theavailable capacity is not used.

Speech appears in spurts, and two partiesdont speak simultaneously. A typical two-way conversation only use 40% of theconnection time.


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Drawbacks of data networks

Quality of Service is not guaranteed. Data

are transmitted in packets. There can be

delays and interruptions, which are not

tolerated in voice transmission


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Evolution of cellular systems (2G)

2G:

GSM: European TDMA

D-AMPS (Digital-Advanced Mobile Phone

System): IS-54 and IS-136 which are TDMAstandards used in the US and have been

replaced by GSM or TDMA2000.

IS-95: IS-95/cdmaOne, CDMA in the US


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Evolution of cellular systems (2.5G)

2.5G

GPRS (General Packet Radio Service)

To transmit and receive TCP/IP based data to and

from GPRS mobile devices

HSCSD: High-speed circuit-switched data,

which is a part of EDGE and UMTS


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Evolution of cellular systems (2.75G)

CDMA2000, 3G standard in the US

EDGE (Enhanced Data for Global Evolution) is a

method to increase the data rates by introducing

a new modulation technique and channelcoding, and thus an add-on to GPRS. EDGE

can transmit three times as many bits as GPRS

during the same period of time.

It uses phase modulation. With 8 phase shift,

three consecutive bits are mapped onto one

symbol. Thus the data rate increases 3 times.


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Comparison: GPRS and EDGE

GPRS EDGE

Symbol rate 270 ksym/s 270 ksym/s

Modulation bit rate 270 kb/s 810 kb/s

data rate/time slot 20 kb/s 59,2 kb/s

data rate/8 time slots 160 kb/s 473,6 kb/s

8


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Evolution of cellular systems (3G)

W-CDMA, European 3G

1xEV-DO (1xEvolution-Data

Optimized)/IS-856, developed by

Qualcomm in 1999 to meet IMT-2000

requirements. US 3G provided by Sprint

and Verizon. Download speed 2.5-3 Mbps.

TD-SCDMA (Time Division-Synchronous

CDMA), Chinese 3G


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Evolution of TDMA

TDMA

GSM

IS-54IS-136

GPRS

(General PacketRadio Service)

EDGE(Enhanced Data

rates for GSMEvolution)

WCDMA

UMTS(Universal MobileTelecom System)

2.5G 2.5G 3G2G

2G


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GPRS (General Packet Radio Service)

Based on GSM

GPRS does not require permanently

allocated physical channels (frequencies

and time slots).


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GPRS (contd.)

Phase 2+ (2.5G)

It provides an "always on", high-speed connection (up to171 kbps in theory, typical 56 kbps) to packet datanetworks, which is suited to the "bursty" traffic on the

Internet and World Wide Web, either directly or viaoperators' portals.

With GPRS, the core network is enhanced to embracethe packet switched domain, adding new IP-connectednetwork elements. Crucially, this extension lays the

foundations of a common core network for 2G and 3G.


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EDGE (Enhanced Data rates for GSM Evolution)

EDGE further enhances GSM/GPRS radio interface byadopting new modulation technology to achieve higherdata rates (180 kbps) using existing GSM radiospectrum.

EDGE is the other pre-3G radio access technologydirectly evolved from GSM. It includes advanced Qualityof Service mechanisms,

Limited data rates compared with WCDMA/TD-SCDMA.Used to provide 3G services in existing 2G spectrumresources.

WCDMA and TD-SCDMA will not necessarily replaceGPRS or EDGE, but will in reality co-exist with them, andcan share one common core network.


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UMTS

UMTS introduces WCDMA for paired bands(5MHz each), as well as TD-SCDMA and TD-CDMA for unpaired bands.

to support High Speed Downlink and Uplink

Packet Access (HSDPA, sometimes called3.5G), enabling transmission at speeds of up to14.2 Mbit/s.

IP Multimedia Subsystem (IMS). It enables real-

time, person-to-person services, such as voiceor video telephony, to be provided by means ofpacket switched technology in common withnon-real-time information and data services.


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UMTS (contd.)

The ability to work with other networks

such as Digital Video Broadcasting (DVB)

and Digital Audio Broadcasting (DAB)

To take advantage of the content offerings

that can be delivered efficiently to phones.


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3GPP (Third Generation Partnership Project)

Established in December 1998

Represents 437 operators and vendorsworldwide. It brings together a number oftelecommunications standards bodies, currently

ARIB and TTC (Japan), CCSA (China), ETSI(Europe), T1 (USA) and TTA (Korea).

to produce globally applicable TechnicalSpecifications and Technical Reports based on

GSM, FDD and TDD. Include GPRS and EDGE.

Standardize WCDMA and CDMA/TD


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GAN/UMA (Generic Access

Network/Unlicensed Mobile Access)

Allowing seamless roaming and handover

between Wi-Fi network and cellular networks

Advantages:

Cheap way to expand coverageRelieves congestion on the cellular spectrum by using

relatively low cost Internet

Particularly good for operators that also offer Internet

services. Can promote both cellular and Internetservices

Improve receiving condition at homes


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The future


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CDMA-2000 family

EV-DV (Evolution-Data and Voice) EV-DVstandard was less attractive to operators,and has not been implemented.

EV-DO (Evolution-Data Optimized) It isstandardized by 3rd GenerationPartnership Project 2 (3GPP2) as part ofthe CDMA2000 family of standards. Dataspeed can reach 2.4 Mbit/s with Rev. 0and up to 3.1 Mbit/s with Rev. A.

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12Evolution of Cellula(1)