Cellular Fundamentals

3G Technologies

Bellevue Community College

Bob Young, Instructor

Overview of 3G

• Transform wireless communications into on-line, real-time connectivity

• Immediate access to location-specific services

• Information on demand

A shift in focus:

3G wireless technology represents a shift from voice-centric services to multimedia-

oriented (voice, data, video, fax) services.

Market "Drivers": Remote access to personalized data Multimedia management Interoperability between a mobile

terminal (phone, PDA etc.) and other electronic devices

Synchronization and uploading of information

Increasing use of the Internet has created a demand for wireless access to the same data

What is 1G?

Analog wireless voice telephone service

Circuit switching technology Examples: In USA, AMPS (Advanced Mobile

Phone Service) In Europe and elsewhere, TACS (Total

Access Communication Systems)

What is 2G? (part 1)

•Early digital mobile phones

•Still using circuit switching technology

•Examples:

•GSM (Global System for Mobiles)

•NA-TDMA

•CDMA

What is 2G? (part 2)

• Some advanced voice services, such as Caller ID

• Some data capabilities, such as fax and SMS (Short Message Service)

• Data rates typically limited to about 9600 bps

• Not suitable for web browsing

• Not suitable for multimedia services

What is 2.5G? (part 1)

A stepping stone towards 3G Higher bandwidths, up to

about 384 Kbps in some cases

What is 2.5G? (part 2)

Examples:

1) High Speed Circuit-Switched Data (HSCSD)

2) General Packet Radio Service (GPRS)

3) Enhanced Data Rates for Global Evolution (EDGE)

What is High Speed Circuit Switched Data?

• HSCSD is one step towards 3G wideband mobile data networks.

• Upgrade to GSM systems

• Circuit-switched technology• Data rates up to 57.6 Kbps

HSCSD implemented in:

Parts of Europe

Hong Kong

Singapore

Israel

South Africa

(To my knowledge, never implemented in USA)

How does HSCSD achieve 57.6 Kbps?

Uses 14.4 kbps data coding Aggregates 4 radio channel

timeslots of 14.4 Kbps 4 x 14.4 = 57.6 Kbps

What is General Packet Radio Service?

• GPRS is an intermediate step towards Internet Services

• Used on GSM networks

• Packet based technology

GPRS Data rates up to 115 Kbps

Some deployed systems are only experiencing 20 - 30 Kbps!

GPRS and IS-136

GPRS can be overlaid on IS-136 (NA-TDMA) networks

(Standards agreement reached in 1999)

GPRS implemented in:

•Parts of Europe

•Hong Kong

•United Kingdom

•United Arab Emirates

•USA

•several other countries

How does GPRS achieve 115 Kbps?

Looks up user profile in HLR/VLR to determine data rate allowed

Assigns multiple time slots (1 to 8) to achieve higher data rates

GPRS is packet based

Data is packetized and transported over an IP backbone

GPRS is compatible with:

SMTP/POPFTPHTTPTelnetand other IP services

GPRS Network

Serving GPRS Support Node is the mobile's access to the data network

Gateway GPRS Support Node is the PLMN access to the Internet

Voice calls are still routed through the MSC

(see next slide for details)

GPRS NetworkGPRS Network

What is EDGE?

Enhanced Data Rates for Global Evolution

Increases throughput for both HSCSD and GPRS

Triples the data rate per time slot

EDGE for HSCSD is called ECSD

• Peak data rate is 64 Kbps, but uses fewer time slots.

• EDGE for GPRS is called EGPRS.

• Peak data rate using all 8 time slots, can exceed 384 Kbps.

• In practice, many operators are seeing only approximately 100 Kbps!

Ericsson's Definition of EDGE (part 1)

"A technology that gives GSM the capacity to handle services for the third generation of mobile

telephony."

Ericsson's Definition of EDGE (part 2)

"EDGE uses the same TDMA (Time Division Multiple Access) frame structure, logic channel and 200kHz carrier bandwidth as today's GSM networks, which allows existing cell plans to remain intact."

Note that Ericsson calls EDGE a "third generation"

technology. • This may be more marketing

hype than reality.

• Most industry insiders consider EDGE a 2.5G "stepping stone" technology to 3G.

EDGE is part of a larger transition

"A year and a half into our program, we believe the decision to migrate to GSM and GPRS/EDGE/3GSM was THE best solution and decision for our company, our customers, and our shareholders...."

- Rod Nelson, CTO, AT&T Wireless

What is 3G?

• Convergence to a single global system

• Data speeds that support streaming audio/video

• Packet switched

• Full support for m-commerce

• Voice becomes a feature - perhaps not the driving characteristic - of the network

Hutchison on 3G

"There's nothing like 3G on the market at the moment. 3G is fusing together two of the most powerful consumer technologies in history - the Internet and the mobile phone."

- Hutchison 3G spokesman Edward Brewster

All paths to 3G involve CDMA technologies

CDMA technology is recognized as providing:

•Clearer voice quality

•Less background noise

•Fewer dropped calls

•Enhanced security

•Greater reliability•Greater network capacity

The ITU has approved 3 standards for 3G mobile

systems:

TD-SCDMAW-CDMACDMA2000

What is TD-SCDMA?

• Standard formulated by China

• No further discussion in this presentation

What is W-CDMA?

•Also called UMTS

•Packet technology for 3GSM

•Current data rate: 384 Kbps

•Future data rate: 1.5 to 2 Mbps

•Then: 8 - 10 Mbps

What is 3GSM? "The technology on which 3GSM services will be delivered is built around a core GSM network with a Wideband-CDMA (W-CDMA) air interface, which has been developed as an open standard. Already over 85% of the world's network operators have chosen 3GSM's underlying technology platform to deliver their third generation services. 3GSM is a key element of GSM-The Wireless Evolution." ( - GSM Association)

3GSM Network

BSS is replaced by RNSBSC is replaced by RNCBTS is replaced by Node B(see next slide for details)

What is CDMA2000?

Full backward compatibility with IS-95B

CDMA 1x (CDMA2000)

Single carrier, 1.2288 MHz (each, uplink and downlink)

Data rate: 144 Kbps now, 307 Kbps in the future

Considered 2.5G, not 3G

CDMA 1x EV-DO (CDMA2000)

Stands for "1x Evolution - Data Only" Data rate: 384 kbps - 2.4 Mbps

3G technology

CDMA 1x EV-DV (CDMA2000)

Stands for "1x Evolution - Data and Voice"

Data rate: 4.8 Mbps 3G technology

CDMA 3x (CDMA2000)

Combines 3 carriers: 3 x 1.2288 MHz = 3.6864 MHz

Data rate: 2 Mbps and higher

Paths to 3GPaths to 3G

3G Spectrum Around the World

Subscriber Growth In USA