overview of wireless networks speaker: jerry gao ph.d. san jose state university email:...

Overview of Wireless Networks

Speaker: Jerry Gao Ph.D.

San Jose State Universityemail: [email protected]

URL: http://www.engr.sjsu.edu/gaojerry

Topic: Overview of Wireless Network

- Overview of wireless networking

- WANs (Wide Area Network)

- Wireless LANs

- PAN (Personal Area Network)

- Challenges and Limitations

Jerry Gao Ph.D.8/02

Presentation Outline

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Types of wireless networks:- Wireless analog network - based on analog circuit-built connections- Wireless digital network - based on package-switched connections

Three types of Wireless Internet Networks:- Wide Area Network (WAN)- Wireless Local Area Network (Wireless LAN)- PAN (Personal Area Network), such as Bluetooth, Infrared

Other classifications:- large, public, cellular phone networks- private in-building wireless networks- room-wide networks

Jerry Gao Ph.D.8/02

Classifications of Wireless Networks

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PAN10 meters

LAN100 meters

WAN2500 meters

Power


Jerry Gao Ph.D.8/02 All Rights Reserved

Landscape of Wireless Networks


Major components and elements of a wireless network:

(a) Different range of wireless towers- Cellular towers- Basestations- Access points (APs)

- These antennaed transceivers communicate with all types of wireless devices, exchange data or voice with them.- They transmit that information through relays and cables eventually back to the wires of the Internet.

(b) Different types of wireless devices - based on radios

Jerry Gao Ph.D.8/02


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Jerry Gao Ph.D.8/02

Revisit of The OSI Seven-Layer Model

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7. Application

6.Presentation

5. Session

4. Transport

3. Network

2. Data Link

1. Physical

7. Application

6.Presentation

5. Session

4. Transport

3. Network

2. Data Link

1. Physical

Request

Response

Peer to Peer

Gateway

Router

Bridge

Relay


Jerry Gao Ph.D.8/02

Wireless OSI Layers

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OSI Layer Internet i-mode WAP

Application IE browser Net Front browser UP browser

Presentation HTML cHTML WML

Session HTTP/HTTPS HTTP/HTTPS WSP

Transport TCP/UDP TCP/UDP WTP/WTLS/WDP

Network IP IP IP

Data link ATM PDC-P PPP

Physical SONET RF (i.e. WCDMA) RF (i.e. CDMA)


There are two network architectures for communicating devices:

A) the telco-favored circuit-switched network connecting voice phonesB) the computer industry favored packet-switched network connecting digital computers

A circuit-switched network: - builds up a circuit for a call, establishes a dedicated two-way connection of circuits between points.- a circuit connection forms a single path between the caller andlistener that last the entire call time.- this circuit is guaranteed regardless of whether you are talking, sending data, or are silent.

A packet-switched network:- route IP-address data packets between points on demand.- packets are routed through multiple paths.- packets are efficient at sending data immediately and are used in i-mode and paging network- Almost every industrial wireless applications uses a packet-based LAN.

Jerry Gao Ph.D.8/02

Circuit-Switched and Packet-Switched Networks

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Jerry Gao Ph.D.8/02

From Analog To Digital Networks

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Jerry Gao Ph.D.8/02


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Internet

TelephoneNetwork

Basestation

Web Phone

Telco Switch

Circuit-switched voice and data

Package-switched data


Internet network:It is known as a global network, which is a collection of host computers that can communication directly.

Telcos:It define the telco network as a series of interconnections. In all cases, these global networks connect to terminals. Each of industry network has its own wireless air interface and protocols for data and voice.

Example: If you use a web phone or make a phone call in the U.S., you access the Public Switched Telephone Network (PSTN).If you access the Post Telephone and Telegraph (PTT). Each is a combination of local, long-distance and international phone networks.

Circuit-switched and package-switched networks use a telco switch to send voice calls through the telephone network, and data transactions to the Internet.

When you use a pure digital system ,such as Cellular Digital Packet Data (CDPD) modem, then you are accessing the wireless Internet without switching.

However, next generation wireless network is moving from a telco-defined, circuit-switched system to an entirely Internet-defined, packet-switched protocol system

Jerry Gao Ph.D.8/02

Telco and Internet Networks

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(a) Different range of wireless towers- Cellular towers- Basestations- Access points (APs)

- These antennaed transceivers communicate with all types of wireless devices, exchange data or voice with them.- They transmit that information through relays and cables eventually back to the wires of the Internet.

(b) Different types of wireless devices - based on radios

Jerry Gao Ph.D.8/02

Phone Number and IP Addresses

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What is WAN? (Citywide Towers Serve Nationwide Networks)

WAN: Radio frequency Communication Speed Range500-1900 Mhz 9600 kbps 2500 meters

WAN is one of the most powerful wide area network, which is licensed public wireless network used by Web cell phones and private radio frequency (RF) digital modems in handhelds.

- In a WAN, cell phones and handhelds with radio modems have antennas that talk with towers:

- macrocell (called supercells), microcell, and picocell.

- The cellular WAN tower often called a Base Transceiver Station (BTS). These are different from TV and broadcast systems.

Broadcast and microwave towers Cellular towers Power a lot very low powerRange hundreds of miles no more than one mileComm. one way broadcast two way signalingfrequency of the electromagnetic spectrum.

Jerry Gao Ph.D.8/02

Wide Area Networks (WAN)

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Cellular Towers:

- The cellular WAN tower often called a Base Transceiver Station (BTS). These are different from TV and broadcast systems.

Broadcast and microwave towers Cellular towers

Power a lot very low powerRange hundreds of miles no more than one mileComm. one way broadcast two way signalingFrequency a specific frequency a specific frequency

- To minimize cost, the cellular towers are clustered and wired back to Basestation Controllers (BSC), which convert the wireless call to a telephone call.

- The entire grid of towers and controllers links back to a telephone exchange called a Mobile Switching Center (MSC), also known as a Mobile Telephone Switching Office (MTSO). The MSC switch calls, and tracks and bills users.

Jerry Gao Ph.D.8/02

Wide Area Networks (WAN)

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Jerry Gao Ph.D.8/02

Wild Area Networks (WAN)

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Cellular tower gridsCellular handoff

Cell phones and handhelds as Radios: They work as two-way radios.The cellular Web phone operates over a moderately powerful licensed and regulated frequency to exchange voice and data with a cell tower.

The typical range:city: 500 – 1000 meters rural cells: up to 25000 meters


Jerry Gao Ph.D.8/02

Three Generations of WAN Air Interfaces

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1 GFDMA

Frequency Division Multiple Access

1980s - each caller has a dedicated frequency

channel:three callers use three

channels

2 GTDMA and GSMTime Division Multiple

Access (TDMA)Group Speciale Mobile

(GSM)

1990s - callers timeshare frequency channel:

nine callers use three channels

3 GCDMA and WCDMA

Code Division Multiple Access (CDMA)

Wide Code Division Multiple Access (WCDMA)

1990s - callers use a shorter bandwidth

2000s - “spread spectrum” each call is spread,

randomly broken down, and mixed.

14 callers use the full bandwidth of one channel.

1 2 3 4 56 7 8 9 1011 12 13 14


Network evolution:

1G (voice-only) analog network|

2G digital network|

3G high-speed data and voice network with many grand features

Jerry Gao Ph.D.8/02

Network Evolution: 1G, 2G, and 3G

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-Each generation can handle more subscribers,generates more revenue.

-One generation does not wipe out the previous, rather a 2G tower operates next to a 1G tower.


Jerry Gao Ph.D.8/02

1G Networks

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History of 1G networks:

First generation analog cellular networks were built strictly for voice calls in the early 1980s.

All 1G networks are based on Frequency Division Multiple Access (FDMA), an air interface that guarantees a dedicated frequency and circuit to each caller.

The Japanese began national service in 1979. The U.S. service, Advanced Mobile Phone Service (AMPS), operates at 800 MHz.Each country has its own 1G air interface protocol.

Major features:- Circuit-switched network- Analog signals- Voice only- AMPS in U.S.


Jerry Gao Ph.D.8/02

2G Networks

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What is a 2G network?- The 2G networks have digital cellular air interfaces.- They were all brought to market in the early 1990s.- The 2G network includes data services, fax, and email.

Almost every wireless device sold in 2002 uses one of the second-generation air interfaces, i.e. TDMA, CDMA, PDC, or GSM)

Major features:- Circuit-switched network- Digital signals- Voice or data overlay- 9 kbps or 19 kbps- Dial-up service


Jerry Gao Ph.D.8/02

3G Networks

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Purpose: 3G networks are designed to support digital packet cellular.

What is 3G network?- 3G is the wireless Internet transmitting voice, data, photos, audio, and

video – all bits running on a wireless packet-based cellular network.

Major features:- Packet switched- TDynamic allocation of voice or data- Transport roaming- Quality sound and video- Data transmission at 2 Mbps- Identification of caller location- W-CDMA, CDMA 2000, TDD, UWC, FDD air interfaces- It is always on.

Transparent roaming – the ability to continue a data or voice call over multiple networks without dropping the call.


What is Wireless LAN Network?

- Wireless LAN (WLAN) refers to the wireless local area network, which has a range of 100 meters. Since wired and wireless LAN protocols are interchangeable from an application viewpoint, it is simple to say LAN.

- In a WLAN, LAN devices talk to a basestation, which is mounted in buildings. They include:

- computers and laptops with wireless cards - handhelds and experimental cell phones

- The LAN network is packet based and fully supports handhelds that can work standalone and offline.

A WLAN operates on unlicensed spectrum.

WLAN or LAN: 2.4. GHZ, 11 Mbps, and 100 meters.

The major advantage: greater wireless data bandwidthBecause WAN cell phone data trickles in at kilobits per second, while WLAN data is measured in megabits per second.

Jerry Gao Ph.D.8/02

LANs: Blockwide Basestations Reach Business and Home

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Applications of Wireless LAN Network:- Provide businesses a private Wireless Network to connect computers, laptops, and wireless handhelds.

- Provide wireless business applications in different areas:

retailing, transportation, distribution, manufacturing, parcel and post delivery, government, health care, and education.

WLAN Standards:

- The most popular industrial WLAN standard is wireless Ethernet, IEEE 802.11b.

- This standard is extremely compatible among vendors.

- A typical basestation operates at 11 Mbps and share 255 devices. However, the individual handheld generally does not get more than 3 Mbps.

- WECA (the Wireless Ethernet Capability Alliance) is helping sponsor IEEE 802.11g, a Higher Data Rate wireless Ethernet that is expected to boost speed to 22 Mbps.

Jerry Gao Ph.D.8/02

LANs: Blockwide Basestations Reach Business and Home

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Two marketing terms, Home Area Network (HAN) and Small Office Home Office (SOHO), designate any wireless LAN that has been priced and designed to work with standard office equipment.

HANs and SOHOs connect home/office computers, printers, telephones, laptops,…. HomeRF (Home Radio Frequency) is the popular wireless network forum led by computer and consumer electronic companies.

- Key standard - the Shared Wireless Access Protocol (SWAP) specifies both voice and data.- HomeRF also operates at 2.4 GHZ and transmits data at 1 to 2 Mbps.

- HomeRF has a 50-meter range and can connect up to 10 devices, including computers, telephone, home theater, and DVD.

- In Sept. 2000, the FCC cleared channels for the operation of HomeRF at 10 Mbps.

Jerry Gao Ph.D.8/02

Home Networks: HAN and SOHO

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Applications of Wireless LAN Network:- Provide businesses a private Wireless Network to connect computers, laptops, and wireless handhelds.

- Provide wireless business applications in different areas:

retailing, transportation, distribution, manufacturing, parcel and post delivery, government, health care, and education.

WLAN Standards:

- The most popular industrial WLAN standard is wireless Ethernet, IEEE 802.11b.

- This standard is extremely compatible among vendors.

- A typical basestation operates at 11 Mbps and share 255 devices. However, the individual handheld generally does not get more than 3 Mbps.

- WECA (the Wireless Ethernet Capability Alliance) is helping sponsor IEEE 802.11g, a Higher Data Rate wireless Ethernet that is expected to boost speed to 22 Mbps.

Jerry Gao Ph.D.8/02

Next Generation Wireless LAN

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What is PAN? (2.4 GHZ, 700 Kbps, and 10 meters) - Personnal Area Network (PAN) is at the bottom of the wireless power range, where transmitters reach about 10 meters, the width of an average room.

- A PAN network operates with nearby devices to exchange data and voice, sometime automatically.

- Unlike the WANs or LANs, PAN requires no tower to operate.

- Wireless synchronization of voice and data is requirement of modern PAN systems.

Jerry Gao Ph.D.8/02

PANs: Roomwide Transmitters Coordinate Nearby Devices

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Objective:- PAN systems are designed to link local devices without using a wire or having to plug in anything.- A PAN system creates and builds on peer-to-peer transfer of information without cables.

PAN Applications Examples:- Remote control of devices and information exchanges.- A PAN web phone transparently passes voice or email between handhelds and laptops.- A radio pen (by the Swedish company Anoto with 3M)that transmits, as it is being written, text or graphics to a nearby transmitter.

Other interesting PAN devices:- sensors, scanners, printers, monitors, magnetic cards readers- wireless cameras, wireless GPS antennas

Jerry Gao Ph.D.8/02

PANs: Roomwide Transmitters Coordinate Nearby Devices

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What is a Bluetooth network?

The BluetoothTM2 network is a low-power, personal, wireless voice and data network that has a range of 10 meters.

Bluetooth wierless technology is positioned to displace infrared data and is a good mechanism to synchronize devices, transfer files, and replace data cables.

- The Bluetooth name and trademarks are owned by Bluetooth SIG, Inc., U.S.A.- A Bluetooth network, called a piconet, can connect up to 8 Bluethooth devices.

- Major features: - automatic synchronization, passthrough of a data/ voice stream for all devices.- a fast-hopping, spread-spectrum radio that operates with 1 milliwatt of power.

Bluetooth Special Interest Group (SIG) is a consortium that includes the funding members IBM, Ericsson, Nokia, Intel, and Toshiba.

Now it has grown to include 2000 other companies, includingMcirosoftware Corp.. Palm, Inc, and other phone and computer vendors

Jerry Gao Ph.D.8/02

Bluetooth Network

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Bluetooth Network Standard --> IEEE 802.15

IEEE 902.15 is the IEEE version of the Bluetooth specification. It serves two purposes:

- specify a version of the Bluetooth network complementary to 802.11 wireless Ethernet.- amplify the Bluetooth ability to transmit 20 Mbps.

(driven by Eastman Kodak Company, which required a wireless format to support downloading photes from a digital camera).

A Bluetooth PAN is convenient for passing conventional voice and small data streams.

The Bluetooth device forecast in 2001 is a $950 million market.

According to Gartner Research in 2000:By 2003, one billion Bluetooth devices are expected to create a $4.5 billion

market.

Jerry Gao Ph.D.8/02

Bluetooth Network

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Jerry Gao Ph.D.8/02

Wireless 2.4 GHz Protocols

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IEEE 802.11b HomeRF Bluethooth

Speed 11 Mbps 1,2, 10 Mbps 30 to 700 kbps

Use Office or campus LAN Home, office, house Personal Area Network

Range 100 meters 50 meters 10 meters

Frequency Direct sequence Wideband frequency Narrowband frequencysharing spread spectrum hopping hopping

Backer Cisco, Lucent, 3Com Apple, Compaq, Dell Ericsson, Motorola,Intel,Apple, Intel, WECA Motorola, Proxim Nokia, Bluetooth Special

HomeRF working interest groupgroup

URL: www.wirelessethernet.com www.homerf.org www.bluetooth.com

Wireless Network Evolution

Cdma2000 QualcomW-CDMA wideband CDMA

3G

Enhanced TDMA, CDMA, GSM2.5G

TDMA time division multiple accessCDMA code division multiple accessGSM global system for mobile comm.

2G

AMPS advanced mobile phone system1G

Wireless TechnologyGeneration



Wireless Network Speed Comparison

54 Mbps802.11a

11 Mbps802.11b

723 KbpsBluetooth

115 Kbps (1-4 Mbps extension)

Infrared IRDA

19.2 KbpsCDPD

SpeedTechnology



Wireless Network Uses

High Speed Lan replacement802.11a

Lan replacement, multimedia802.11b

Device interconnect, voiceBluetooth

Device interconnect, data syncInfrared

Short text bursts – stock quotes sports scores

CDPD

FunctionTechnology



Challenges and Issues

• Aggressive pricing – a by-product of increased competition – has reduced average airtime revenue per subscriber.

• Second generation network technologies are short on bandwidth and QoS (quality of service) assurances.

• Wireless network coverage is not as robust in the US as elsewhere, many US users may become frustrated trying to access the Web when they need information.

• Up-front costs of wireless networking, both at the service provider and corporate levels, are steep.



overview of wireless networks speaker: jerry gao ph.d. san jose state university email:...

Documents

wireless analog network

network architectures

paging network

wireless networks room

wireless osi layers

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wide networks jerry

limitations jerry gao