wireless communication: wc-unit 8,VTU EC students

7/25/2019 wireless communication: wc-unit 8,VTU EC students

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Objectives

By


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Objectives


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This unit deals with different wireless IEEE standards like LANs, PANs and MANs are used

for high performance wireless computer networks that are used in a variety of different

operating space with a wide range of data throughput speeds.

Discuss the basic differences between wireless LANs and wireless mobile systems.

Discuss the evolution of the IEEE 802.11 standard and its extensions IEEE 802.11x.

Discuss the fundamental differences between wire and wireless LANS

Explain the basic architecture of IEEE 802.11 wireless LANs

Discuses the 802.11 design issues.

Discuss the basic differences between wireless PANs and WLANs

Discusses the evolution of the IEEE 802.15 standard from the Bluetooth standard Discuss the basic differences between wireless LANs and wireless mobile systems basic

characteristics of a WLAN are presented and contrasted against the basic operation of a

WLAN.

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Objectives

U n i t 8 - L e a r n i n g O b j e c t i v e s


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Discuss the various types of wireless PAN networks that may be setup under the 802.15

standard.

Describe the short history of the IEEE 802.16 standard.

Explain the basic difference between wireless MANs,WLANs and WPANs.

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Objectives

Cont inue.


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802.11 is an IEEE standard for MAC and Physical Layer for Wireless Local Area Network(WLAN).

A wireless local area network(WLAN) links two or more devices using some wireless distribution

method (typically spread-spectrumor OFDMradio), and usually providing a connection through an

access point to the wider internet.

This gives users the mobility to move around within a local coverage area and still be connected to the

network.

Most modern WLANs are based on IEEE 802.11standards, marketed under the Wi-Fibrand name.

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Objectives

1. Introduction to IEEE 802.11x Technologies
http://en.wikipedia.org/wiki/Spread_spectrumhttp://en.wikipedia.org/wiki/OFDMhttp://en.wikipedia.org/wiki/IEEE_802.11http://en.wikipedia.org/wiki/Wi-Fihttp://en.wikipedia.org/wiki/Wi-Fihttp://en.wikipedia.org/wiki/Wi-Fihttp://en.wikipedia.org/wiki/Wi-Fihttp://en.wikipedia.org/wiki/IEEE_802.11http://en.wikipedia.org/wiki/OFDMhttp://en.wikipedia.org/wiki/Spread_spectrumhttp://en.wikipedia.org/wiki/Spread_spectrumhttp://en.wikipedia.org/wiki/Spread_spectrum


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The IEEE 802.11x standards form the basis for the implementation of high

performance wireless computer networks.

The IEEE 802.11 x standards define the over the air protocols necessary to support

networking in a LAN environment.

The significance of IEEE 802.11x standards were written to provide a wireless

extension to the existing wired standards.

This comprises of a PHY (Physical) and MAC (Medium Access Control) Layer.

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Objectives

contd


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Technical specification of IEEE 802.11(Initial standard)

It was released in 1997 and clarified in 1999.

Operating frequencies = 2.4 GHz range bandwidths.

Data rates = 1 or 2 Mbps.

There are two Modulation types for these technologies used

o Frequency Hopping Spread Spectrum (FHSS) : Used for low power, low-range

applications.

o Direct Sequence Spread Spectrum (DSSS):It is popular with Ethernet-like data rates.

It is also addressed the use of IR light within the physical layer specifications.

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ObjectivesContd.


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Goals of WLAN standard

a) Seamless roaming

b) Message forwarding

c) larger range of operation

d) Support for a large number of users

e) To achieve maximum data rates

Limitations in the basic standard

a) Limited data rates

b) Lack of security

c) Single frequency band operation

d) Not address the QoS

e) Interference from the other services

f) Not interoperability between different vendor access points(APs)

IEEE 802.11x working groups have continue to meet and refine the and address the above issues8

ObjectivesContd


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In 1971, ALOHA-Net project implementation by network and radio technologies.

In 1980s, "Ham" radio operators design and build network terminal node controllers.

In 1985 commercial development of radio-based LANs began in US. The ISM bands located

between 920 MHz and 5.85 GHz to the public, It is shown in figure below

In 1990,the microelectronics group at Lucent Technologies launched one of the first commercially

successful WLAN products lines.

In 1994, a new WLAN suite for use in 2.4 GHz started.

In 1997 initial 802.11 standards was initialized, max. data rate of 2Mbps. 9

Objectives2. Evolution of wireless LANs *** (2012)


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In 1997- IEEE 802.11a specified operation up to 5Mbps,5Ghz range.

IEEE 802.11a operation up to 11 Mbps in 2.4Ghz band called High Rate or Wi-Fi.

In 2003,IEEE another extension adopted for 54Mbos in 2.4 Mbps band only.

Later projects, motivates on enhance the data rate up to 200Mbps,1000mts distance,

Internetworking and external networking ability ,management enhancement and auto

reconfiguration of network parameters.

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ObjectivesCon t i nue .


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The Wireless Local Area Network (WLAN) technology is defined by the IEEE 802.11 family of

specifications.

The IEEE 802.11 standard

Maximum data rate rate of 2 Mbps.

Operated in 2.4 GHz band using either FHSS or DSSS.

Most wired LAN operated at either 10 or 100 Mbps.

The IEEE 802.11a Standard

Data rates up to 54 Mbps in the 5-GHz frequency band.

It uses an OFDM encoding scheme rather than FHSS or DSSS.

This specification applies to wireless ATM systems and is used in access hubs.

It supports for a number of set "fall-back rates" when the radio channel condition cannot support

the highest possible data rate.

The IEEE 802.1Ib Standard

It is also referred to as High Rate or Wi-Fi standard

Data rate of 11 Mbps in the 2.4 GHz band.

It uses only DSSS.

The IEEE 802.11g Standard

It offers wireless transmission over relatively short distances at 20 - 54 Mbps in the 2.4 GHz band.

It uses the OFDM encoding scheme. 11

ObjectivesExtensions to 802.11


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The IEEE 802.11e Standard

It enhance the 802.11 media access control (MAC) specification to expand support for LAN

applications that have Quality Of Service(QoS) requirements.

The applications include transport of voice, audio, and video over 802.11x networks.

Voice over WLANs (VoWLAN) has started to receive a larger share of attention for mobile users.

The IEEE 802.11f Standard

It supports multiple vendor access point (AP) interoperability across a distribution system

(DS) supporting IEEE 802.11 wireless LAN links.

The IEEE 802.11h Standard

It enhance the current 802.11 MAC and 802.11a PHY specifications with network

management and control extensions in 5-GHz band.

These enhancements would provide improvements in

Channel energy management

Throughput measurement and reporting functions

Dynamic channel selection

Transmit power control functions.

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ObjectivesContinue.


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The IEEE 802.11i Standard

It enhance the 802.11 MAC to enhance security and authenticate mechanisms.

The IEEE 802.11j Standard

It enhance the standard to add newly available 4.9- and 5.0-GHzchannels for operation in Japan

The IEEE 802.11k Standard

It enhance the scope of radio resource measurements from only internal use, to allow access to

these measurements to external entities.

This will allow for the introduction of WLAN mobility management functions .

The IEEE 802.11ma Standard It update the standard by providing editorial and technical corrections.

The IEEE 802.11n Standard

It enhance the WLAN user's experience by providing data throughput rates in excess of 100 mbps.

The IEEE 802.11p Standard

It enhance WLAN technology ability to communicate between vehicles at speeds up to 200 km/h . This project has the aim of enhancing the mobility and safety of all surface transportation.

The IEEE 802.11r Standard

It improve basic service set (BSS) transitions (i.e., WLAN handoffs) within 802.11 extended service

sets (ESSs) to prevent the disruption of data flow during these events.

This will enhance the operation of applications like VoIP.13

ObjectivesContinue.


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The IEEE 802.11s Standard

It support WLAN mesh operation by providing the protocol for auto configuring and

multi-hop topologies in an ESS mesh network.

The IEEE 802.11u Standard

It enhance the IEEE 802.11 MAC and PHY layers to provide the ability to internetwork

with other external networks.

The IEEE 802.11v Standard

It provide wireless network management enhancements to the IEEE 802.11 MAC and

PHY layers .

It provides the means to retrieve data about station operation, this extension will

provide the ability to configure the station.

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ObjectivesContinue


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Basic Operating frequencies = 2.4 to 5 GHz range bandwidths.

Data rates = 1 to 100 Mbps.

Modulation types used are FHSS,DSSS,OFDM.

It is also addressed the use of IR light within the physical layer specifications.

It support for LAN applications that have Quality Of Service(QoS) requirements, for video

conferencing and media stream distribution.

It allows an inter-access point protocol (IAPP) to allow for multiple vendor access point (AP)

interoperability across a distribution system (DS) supporting IEEE 802.11 wireless LAN links.

It provide spectrum and transmit power control management in the unlicensed 5-GHz band.

It provide enhance security and authenticate mechanisms.

It provide services to enhancing the mobility and safety of all surface transportation.

This will enhance the operation of applications like VoIP.

It has auto configuring and multi-hop topologies in an ESS mesh network.

It has capability to provide service with other external networks.15

ObjectivesList the features of 802.11x technologies***(2011)

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Implement the simplest form of a wireless LAN, needs two or more WLAN enabled PCs.

Ad-hoc or peer-to-peer wireless network can be configured with a peer-to-peer operating

system.

Both the radio cards and AP contain radio transceiver hardware that provides the radio link

for the transmission of data back and forth between the units.

The radio card or embedded Wi-Fi chip set to be analogous to the mobile station of the

wireless mobile network, whereas the access point plays the role of the cellular radio base

ration.

The major differences between the two wireless systems at the physical layer level are the

form of modulation used, the frequency bands employed, and the range of operation.

one's connectivity to the internet or the PDN via the WLAN may be provided by a wireless

internet service provider (WISP),

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ObjectivesLayer 1: Overview ( WLAN architecture)

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In a WLAN, the addressable unit is known as a station (STA ). The wireless enabled station serves as a message

destination but in general does not indicate a fixed location.

Wireless radio links are highly unreliable.

Some of the effects to be considered when designing a wireless LAN, such as:

Wireless LAN can have actively changing topologies

WLAN radio link signals are not protected from outside EM interference

WLAN radio links experience time-varying multipath effects.

WLANS have neither absolute nor observable boundaries.

WLAN required to handle both mobile and portable stations and deal with battery powered equipment.

Mobile stations by definition are actually in motion and moving about the WLAN whereas portable

stations may be moved about to different locations within the WLAN but are only used while at a fixed

location.

The fact that a station may be battery powered gives rise to power management schemes that might

require a WLAN station to go into the sleep mode.

The basic topologies (known as service sets) supported by the IEEE 802.11 architecture are as follows.

1. Independent Basic Service Set Networks

2. Distribution System Concepts

3. Extended Service Set Networks

4. Integration of Wired and Wireless LANs17

Objectives3. IEEE 802.11 DESIGN ISSUES****

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The Basic Service Set (BSS) is the simplest and most fundamental structure of an IEEE 802.11x WLAN.

See Figure below for a diagram of an independent BSS (IBSS).

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Objectives3.1 Independent Basic Service Set(BSS) Networks

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Architecture description:

There is no backbone infrastructure and the network consists of at least two wireless stations. This

structure is sometimes referred to as a peer-to-peer or ad hoc wireless network.

The propagation boundary will exist but its exact extent and shape are subject to many variables.

simulation software exists that can provide some reasonable estimates of RSS for typical multi-floor

architectural layouts and various building materials.

It is also possible to have two or more of these IBSSs in existence and operational within the same

general area but not in communication with one another.

Within the IBSS structure, the association between an STA and a BSS is a dynamic relationship.

An STA may be turned on or off or come into or go out of range of the BSS an unlimited number of

times.

The STA becomes a member of the BSS structure when it becomes associated the BSS.

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ObjectivesContd..

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In WLAN the maximum station-to-station distance that may be supported is determined by

many factors including RF output power and the propagation conditions of the local

environment.

To providefor an extended wireless network consisting of multiple BSSs, the standard allowsfor an architectural component known as the Distribution System (DS).

Figure below shows a diagram of a distribution system and several access points serving

different BSSs.

To provide flexibility to the WLAN architecture, IEEE 802.11 logically separates the wireless

medium (WM) from the Distribution System Medium (DSM).

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Objectives3. 2 Distribution System Concepts

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The function of the DS is enable mobile device support.

It providing the logical services necessary to perform address-to-destination mapping and

the seamless integration of multiple BSSs. This function is physically performed by a device

known as an access point (AP).

The AP provides access in the DS by providing DS services and at the same time performing

the STA function within the BSS.

In Figure 9.3, data transfers occur between stations within a BSS and the DS via an AP.

All the APs are also stations and as such have addresses. However, the address used by an AP

for data communications on the WM side and the one used on the DSM side are not

necessarily one and the same.

This DS structure gives rise to the use of APs as bridges to extend the reach of a network.

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The IEEE 802.11 standard provides for the use of multiple BSSs and a DS to create a wireless

network of arbitrary size and complexity networks are known as extended service set (ESS)

networks shown in figure below

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Objectives3.3 Extended Service Set Networks

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ESS networks provide advantages, so that stations within an ESS network may communicate

with one another and mobile stations may move transparently from one BSS to another as

long as they are all part of the same ESS network.

Due to use of an ESS network all of the following situations may occur:

BSSs may overlap to provide continuous coverage areas or BSSs can be physically separate entities

BSSs may be physically collocated for redundancy reasons, and one or more IBSS or ESS networks

may be physically located in the same area.

The above situation can commonly occur when separate organizations set up their own WLANs in

close proximity to one another.

The above problems in wireless LAN architecture solved by a device known as a portal.

To integrate the 802.11 wireless LAN with a traditional 802.x wired LAN (see Figure 9.4) aportal or logical point must exist where medium access control (MAC) service data units or

MSDUs can enter the wireless LAN distribution system.

The portal's function is to provide logical integration between the wireless LAN architecture

and the existing wired LAN. 23

ObjectivesContinue

Objectives


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Wireless Technologies (reference only)

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Objectives2. Wireless PANs / IEEE 802.15x

PAN(Personal Area Network)

LAN(Local Area Network)

WAN(Wide Area Network)

MAN(Metropolitan Area Network)

PAN LAN MAN WAN

Bluetooth

Peer-to-PeerDevice-to-Device

Short


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This section deals with

IEEE 802.15x standard for wireless personal area networks (WPANS).

Comparison of the functionality provided by a wireless LAN and a wireless pan

Introduced to the origins of IEEE 802.15xthe Bluetooth specifications.

The basic characteristics of a WPAN are presented with contrasted against the

basic operation of a WLAN.

The Bluetooth physical layer details for 2.4-ghz operation.

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Objectives2. Wireless PANs / IEEE 802.15x

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Introduction:

WPAN (Wireless Personal Area Network) is used to transfer the information over short distance

between private groupings of participant devices.

The goal of standard was to provide a ultra-low complexity, cost, and power for low-data-rate

wireless connectivity among fixed, portable, and moving devices either within personal operating

space (POS).

A POS is further defined as the space around an individual or object that typically extends ten

meters in all directions and envelops the individual whether that person is stationary or in motion.

The standard has been developed to coexist with all other IEEE 802.11 networks.

The implementation of a WPAN can be achieved through small, extremely power-efficient,

battery-operated, low-cost solutions for a wide and diverse range of personal devices.

Some a these emerging technologies for implementation of ubiquitous wireless sensor networks

(WSNs) supporting applications for use in both the commercial/industrial and consumer/home

environments.26

Objectives2.1 INTRODUCTION TO IEEE 802.15X TECHNOLOGIES

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Wireless PAN Applications

It heavily used in low-cost, battery-operated personal digital assistants (PDAs),

personal 1v1P3 music players, digital cameras, and multimedia-enhanced mobile

phones.

These devices in conjunction with the more traditional notebook/laptop and newer

tablet computers

Industrial sensor applications like Low speed, low battery, low cost sensor networks

Personal home storage

Printers & scanners

Interactive video gaming

Home theater

Exchanging information directly between PDAs

Connecting a keyboard or mouse wirelessly to a desktop computer

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Objectives2.2 . WIRELESS PAN APPLICATIONS AND ARCHITECTURE

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Infrared Wireless LAN

Bluetooth

Also an IEEE standard 802.15.1

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ObjectivesWPANs Technologies (reference only)

Project Data Rate Range Configuration Other Features

802.15.1

(Bluetooth)

721 kbps 1 M (class3)

100 M (class1)

8 active device

Piconet/

Scatternet

Authentication,

Encryption, Voice

802.15.3

High Rate

22, 33, 44,

55 Mbps

10 M peer-to-peer FCC part 15.249

QoS, Fast Join,

Multi-media

802.15.4

Low Rate

Up to

250 kbps

10 M nominal

1~100 M (based

on settings)

Star

peer-to-peer

Battery life: multi-

month to multi-

year

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B i WPAN Ch t i ti


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Short Range (at least 10m, up to 70m possible)

Data rates (currently up to 55 Mb/s)

Short time to connect (


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Both WLANs and WPANs appear to be very similar in their operation.

The three fundamental ways in which these two technologies differ:

1. WPAN power levels and coverage areas

2. Media control techniques

3. Network life span or duration

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ObjectivesDifference between WPAN and WLAN***

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1. WPAN power levels and coverage areas

A WLAN

Power Level : Approximately 100 mw

Coverage Distances : Approximately 100 Meters

Mobility : It enables fixed or less mobility

Access Points (AP): Need To Be Placed In Optimized Fixed Locations

Deployment of a WLAN where the use of cables is either difficult or costly to install.

The WLAN must still be deployed and set up in any case and primarily serves to extend the reach of a

portable device to connect to an established infrastructure.

The WPAN:

Power Level : Approximately 1mw

Coverage Distances : Approximately few 10 meters

Access Points (AP): Need not to be placed in optimized fixed locations

A WPAN uses low power consumption to enable true mobility.

Personal devices are able to achieve low-power modes of operation that allow several devices to share

data through the use of WPAN technology.31

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2. Media control techniques

PAN standard consists of the formation of ad hoc networks that are controlled by a single

member of the PAN known as the master andthe other member or members of the ad hoc PAN

function as slaves and it is interchangeable.

It uses of a time-multiplexed slotted system.

the master is able to poll the slave members of a wireless PAN and thus determine the required

bandwidth needs.

the master is then able to regulate the bandwidth assigned to the various slave personal devices

based upon the required QoS requested.

Through use of a system that employs short timeslots high-quality traffic may be supported.

A WLAN device is required to maintain management information database (MB) to facilitate end-

to-end network operations of a larger infrastructure.

The WPAN device presently does not need to maintain a network-observable and network-

controllable state to provide this type of WLAN functionality.

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3. Network life span or duration

For a WPAN, a device can create a connection that lasts only as long as needed and

therefore the network has a finite life span.

Eg: If a digital picture is to be transferred from a camera to a PC, the network might

exist only as long as needed to transfer the picture.

Since the connections created in a WPAN are ad hoc and temporary in nature.

the WPAN allows for the rapid formation of ad hoc networks that provide wireless

connectivity without any pre deployment activity necessary

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Advantages and Disadvantages of WPAN


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Advantages:

Dynamic network setup

Usually quick and relatively simple to set up

WPAN enabled devices are usually portable

Needs less technical skills to deploy than LANs or WLANs.

Disadvantages:

Typically have a limited range

Currently limited to relatively slow data rates when compared with WLAN technologies

Compatibility and interoperability issues (WPAN technologies are not usually compatible with each

other. Some WPAN technologies such as Bluetooth are known to have had interoperability issues

between devices from different manufacturers.)

As small devices that are often associated with WPANs often have limited potential for adding extra

hardware it is sometimes difficult to find suitable upgrade equipment.

Devices with inbuilt WPAN technologies can be considerably more expensive than devices without

WPAN technologies. 34

ObjectivesAdvantages and Disadvantages of WPAN

Objectives

Bluetooth WPAN Overview


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Introduction

Bluetooth is a low tier, ad hoc, terrestrial wireless short-range radio technology.

Goal is to replace cables.

This technology used to facilitates more way of exchanging data between telephones,

computers and other devices.

The Bluetooth wireless technology comprises hardware, software and interoperability

requirements.

Transmits at up to 1 Mbps over a distance of 33 feet and is not impeded by physical barriers

The Bluetooth provides support for both asynchronous and synchronous communications.

o Asynchronous channels for data transfer .

o synchronous channels for telephony-grade voice communications.

Using Bluetooth wireless technology, a user could simultaneously be provided hands-free

cellular telephone operation via a Bluetooth-enabled wireless headset and at the same time

be transferring packet data from the cellular mobile phone to a laptop / notebook PC.

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ObjectivesBluetooth WPAN Overview

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Bluetooth Specification:

1. Standard is IEEE 802.15.1

2. Operate 2.4-GHz unlicensed ISM band.

3. FHSS is employed to prevent interference and signal fading.

4. Data rate of 1Mbps.

5. Use low power 30 to 100mA active current.

6. Antenna power 0dbm (mW) to cover 10mts

7. FSK modulation is used at a symbol rate of 1 Msps.

8. The use of frequency hopping at a rate of 1600 hops/s or 625 ms/hop.

9. Use full-duplex operation using a TDD scheme.

10. A packet normally is only a single slot in length but can be extended up to 3 or 5 slots.

11. Data traffic can have a maximum asymmetric rate of 723.2 kbps between two devices.

12. Bidirectional, synchronous 64-kbps channels are able to support voice traffic between 2 devices.

13. Various combinations of asynchronous and synchronous traffic are allowed.36

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Continue


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Bluetooth packet data format:

Figure 10.2 shows the format of an over the air, single-slot Bluetooth packet. The figure

indicates that each packet consists of an access code, a header, and a payload.

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Continue


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Figure 10.3 depicts Bluetooth wireless technology and the OSI model.

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Bluetooth WPAN Ad Hoc Network Topologies


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The two basic types network topologies.

1. Piconet

2. Scatternets.

1. piconet :

It is formed by a Bluetooth device serving as a master and at least one or more (up to a maximum of

seven) Bluetooth devices acting as slaves (see Fig 10.4).

All devices that are taking part in a piconet are synchronized to the clock of the master of the piconet and

hence to the same frequency hopping sequence.

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jBluetooth WPAN Ad Hoc Network Topologies

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Continue


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The piconet is defined by the frequency hopping scheme .

The piconet slaves only communicate with the piconet master in a point-to-point fashion

and under the direct control of the master.

The piconet master may communicate in either a point-to-point or point-to-multipoint

fashion.

Various usage scenarios might tend to define a certain device's role within a piconet as

always being either a master or a slave; however, the standard does not define permanent

masters or slaves.

A device that has served as a slave for one application could just as easily be the master in

another situation.

Slave can communicate with only master, not with other slaves in the piconet.

Non active slaves can be put in stand by mode (Sleep mode) to save the power.

48 bit ID are used for the devices identification in the piconet.

The hopping pattern is determined by device ID.40

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2. Bluetooth scatternet structure:

The scatterenet is a collection of functioning piconets overlapping in both time and space

(see fig below)

Bluetooth device may be member of several piconets involves in a scatternet at the same

time, but can only be a master of a single piconet.

A device may serve as both a master and a slave within the scattemet.

The Device in scatternet in imply any routing capabilities

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Continue.

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Continue


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Integration of a Bluetooth WPAN with other LANS

use of an IEEE 802 LAN attachment gateway (AG) a Bluetooth WPAN may connect to and participate in

the transfer of data with other LANs in the IEEE 802 family.

The LAN Attachment Gateway(AG) allows for the transfer of MAC service data units (MSDUs) from or to

other LANs via the wireless connectivity afforded by the Bluetooth WPAN.

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Continue.

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Components of the Bluetooth Architecture***


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Components of the Bluetooth Architecture

Figure below shows the Bluetooth protocol stack.

The Bluetooth standard call for a set of communication protocols and a set of interoperable application

that are used to support the usages address in the specifications.

Figure below shows both Bluetooth-specific protocols and other non-Bluetooth-specific protocols.

The link manager protocol (LMP) and the Logical Link Control And Adaptation(L2CAP) layer protocol are

Bluetooth specific whereas the protocols within the "Other" box are not.

Some of these other protocols are the point-to-point protocol (PPP) and wireless application protocol

(WAP).

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Continue


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44

Continue

Layer Description:

1. Physical radio layer: It for Tx and Rx data and voice.

2. Baseband layer: It enables RF link between Bluetooth devices.

3. Link manager: It is the protocol that handles link establishment b/w Bluetooth devices which

include authentication and encryptions.

4. LLC and L2CAP: It is connection based communication protocol that implements multiplexing. No

flow control. But provide reliable base band link.

5. Audio profile: It responsible for managing connection for Tx ?Rx data from audio devices.

6. Control : For control signal generations fro various activities.

7. Other LLC: Link controller for optional device, fax, headsets like cordless phone etc.

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3 Broadband Wireless MANs/IEEE 802 16x


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3. Broadband Wireless MANs/IEEE 802.16x

3.1 Introduction WMAN/IEEE 802.16X Technologies

The IEEE 802.16x standards for wireless metropolitan area networks (WMANs)

This systems can be used to provide multiple types of data services to system subscribers.

The main goal of WMAN to Provide high-speed Internet access to home and business

subscribers without wires.

Base stations (BS) can handle thousands of subscriber stations (SS). Access control

prevents collisions.

Supports

Legacy voice systems

Voice over IP

TCP/IP

Applications with different QoS requirements.

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3 Broadband Wireless MANs/IEEE 802 16x(reference only)


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3. Broadband Wireless MANs/IEEE 802.16x(reference only)

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Contd.

The origin and evolution of IEEE 802.16x

In 1999. IEEE 802.16 project was started to promote the use of innovative and cost-effective broadband

wireless products on a worldwide basis.

The first specifications provide for the transport of data, video, and voice services at frequencies band of

10 to 66 GHz.

Initially it is a expensive type of broadband access technology accept in a few isolated, scattered areas.

The original IEEE 802.16 standard called for operation in licensed bands in the 10- to 66-GHz frequency

range where line-of-sight (LOS) is required for satisfactory operation.

The original standard has been amended to include operation in the 2- to 11-GHz frequency range in both

licensed and unlicensed bands.

Intel is reportedly planning to design and produce an IEEE 802.16-compatible chip set.

the term Wi-Max (similar to Wi-Fi) has been adopted to describe this technology.

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802.16 standards:


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802.16.1 (10-66 GHz, line-of-sight, up to 134Mbit/s)

802.16.2 (minimizing interference between coexisting WMANs.)

802.16a (2-11 Ghz, Mesh, non-line-of- sight)

802.16b (5-6 Ghz)

802.16c (detailed system profiles)

P802.16e (Mobile Wireless MAN)

.

802.16 standards:

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IEEE 802.16 and 802.16a Standards


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49

The IEEE 802.16

This standard was adopted by the IEEE Standards Board in 2001.

this standard only covered physical layer implementations for the 10-66 GHz frequency range.

The MAC layer only supports LOS operation over fairly large channels (i.e., 25 to 28 MHz wide)

This can support raw data rates in excess of 120 Mbps.

application area for this form of wireless technology was broadband Internet access for the small

office/home office (SOHO).

The IEEE 802.16a

This standard was adopted in 2003.

Initially called IEEE 802.16.1 was incorporated into IEEE 802.16 and IEEE 802.16.3 became 802.I6a.

IEEE 802.16a-2003 adds support for operation in license-exempt bands and an optional mesh

topology (for NLOS propagation) at these lower frequencies.

A further revision to IEEE 802.16 is presently in the formulation stages and is meant to consolidate

IEEE 802.16. 802.16a, and 802.16c (another amendment) into one unified and updated 802.16

wireless standard.

IEEE 802.16 and 802.16a Standards

Objectives

3.2 IEEE 802.16 WIRELESS MANS


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3.2 IEEE 802.16 WIRELESS MANS

Wireless metropolitan area networks (MANs) provide network access to buildings through

exterior antennas communicating with a central radio base station over a point-to-multipoint.

Objectives

Contd.


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Contd.

It is a low cost of deployment of wireless MAN (WMAN) technology, it certainly should prove

cost-effective compared to the installation of fiber-optic links.

It provide the required bandwidth capacity since they are shared systems designed for high-

speed net access for the home user.

In many instances, wireless MAN technology could provide network access where DSL

technology would fail due to distance limitations or severe copper pair signal impairments.

At present, the use of wireless MANs that conform to the IEEE 802.16 standard brings the

network to the building.

Users inside the building connect to the network with conventional in-building network

technologies like Ethernet or possibly wireless LANs (IEEE 802.11).

IEEE 802.I6e allow an extension of the standard to provide network connectivity to an

individual's laptop/notebook/tablet computer or PDA while outside, in one's home orapartment, or while in a moving vehicle.

A wireless MAN effectively serves as a bridge to an existing network infrastructure.

This bridge function may extend the network wirelessly to multiple new fixed locations

where the network deployment might use standard network infrastructure to provide

network connectivity to the end users.

Objectives

WMAN v/s WLAN and WPAN


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/s a d

WLAN has a maximum reach in the order of 100 meters for indoor access points whereas

wireless MANs may span several thousands of meters in an outdoor environment.

The WLAN also may provide an outdoor bridge function over many kilometers of distance

but it is usually only for specific point-to-point applications.

The wireless PAN does not appear to have any commonality with the wireless MAN except

for the functionality exhibited by the wireless PAN piconet and the wireless MAN mesh

network operation.

WPANs, tens of meters (piconets) versus kilometers for the wireless high-speed MAN.

Objectives

IEEE 802.16 WMANS Typical Deployment


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yp p y

A wireless MAN base station is typically located on a tall building to provide an unobstructed

or line-of-sight path between the subscriber stations and the base station antennas.

Although the new IEEE 802.16a physical layer standard provides for NLOS operation at

frequencies between 2-11 GHz.

substantial base station antenna height is still desired because the best system operation

with the highest possible data transfer rates.

Data rates is dependent upon base station to subscriber station radio channel

characteristics.

a direct LOS path will provide the best channel transmission characteristics. Even with mesh

network operation the greater the number of mesh stations with LOS views of the mesh

base station, the better the system operation.

Objectives

Contd


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For LOS operation, a typical cell radius for a wireless MAN system with the base station

antenna at a height of 30 meters and the SS antenna at 6.5 meters is approximately 3.5 km.

For an 80-meter base station antenna height the cell radius increases to about 7 km.

System bit rates are dependent upon the system bandwidth and the coding/modulation

formats used.

Typical operational values range from 5 to l0s of mbps in the 2-11 GHz range and higher

values for systems deployed in the 10-66 GHz range.

The subscriber station antenna is typically mounted on an outside building wall, base station

facing window, or on a pole aimed at the base station antenna.

To increase system capacity, a wireless MAN base station usually supports numerous

antenna sectors.

Sectored antennas are used with frequency reuse concept to meet the system capacity.


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THE END OF UNIT 8Wireless LANs/IEEE 802.11x

Wireless PANs/IEEE 802.15xWireless MANs/IEEE 802.16x


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J.J. Thomson [Father of e-]


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Born 18 December 1856Manchester, Lancashire,

UK

Died30 August 1940 (aged 83)

Cambridge, UK

Nationality British

Fields Physics

Institutions University of Cambridge

Known forPlum pudding modelDiscovery of electron

Discovery of isotopes

Mass spectrometer

invention

First m/e measurement

Proposed first waveguide

Thomson scattering

Thomson problem

Notable awards Nobel Prize for

Physics(1906)

Signature

Documents

wireless communication: wc-unit 8,VTU EC students