wc nots final unit new 8

Wireless Communication: Unit 8 – WLAN-802.11x/WPAN-802.15x/WMAN-802.16x

Prof. Suresha V, Dept. Of E&C E. K V G C E, Sullia, D.K-574 327

UNIT-8

Wireless LANs: IEEE 802.11x / Wireless PANs: IEEE 802.15x

Wireless MANs: IEEE 802.16x

Learning Objectives: Upon completion of this unit, the student should be able

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.

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.

8.1 Introduction to IEEE 802.11x Technologies

802.11 is an IEEE standard for MAC and Physical Layer for WLAN.

WLAN links two or more devices using some wireless distribution method 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 802.11 standards, marketed under the

Wi-Fi brand name.

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.

http://en.wikipedia.org/wiki/IEEE_802.11

http://en.wikipedia.org/wiki/Wi-Fi



Technical specification of IEEE 802.11(Basic standard)

o It was released in 1997 and clarified in 1999.

o Operating frequencies = 2.4 GHz range bandwidths.

o Data rates = 1 or 2 Mbps.

o There are two Modulation types for these technologies used

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

range applications.

Direct Sequence Spread Spectrum (DSSS): It is popular with Ethernet- data

rates.

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

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)

8.2 Evolution of wireless LANs *** (July-2014-6M, Dec-2012-6M)

IEEE 802.11x working groups have continued to meet and refine and address the

limitation issues in the basic standard.

• The IEEE 802.11 standard

– Maximum data 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.

• The IEEE 802.11e Standard – It enhances 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.

• The IEEE 802.11i Standard

– It enhances the 802.11 MAC to enhance security and authenticate mechanism.

• 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 enhances 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 updates the standard by providing editorial and technical corrections.

• The IEEE 802.11n Standard

– It enhances the WLAN user's experience by providing data throughput rates

in excess of 100 mbps.



• The IEEE 802.11p Standard

– It enhances 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.

• The IEEE 802.11s Standard

– It supports 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 enhances the IEEE 802.11 MAC and PHY layers to provide the ability to

internetwork with other external networks.

• The IEEE 802.11v Standard

– It provides 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.

List the features of 802.11x technologies***(Jan-2015-6M,July-2013-5M, July-2011-8M)

• Basic Operating frequencies = 2.4 to 5 GHz range bandwidths.

• Data rates = 1 to 100 Mbps.

• Modulation types used are FHSS, DSSS, and 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 provides enhance security and authenticate mechanisms.

• It provides services to enhancing the mobility and safety of all surface

transportation.

o This will enhance the operation of applications like VoIP.

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

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



Layer 1: Overview (WLAN architecture)

• Implement the simplest form of a WLAN, 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 MS of the wireless

mobile network, whereas the access point plays the role of the cellular RBS.

• 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.

8.3 IEEE 802.11 DESIGN ISSUES****

In a WLAN, the addressable unit is known as a station (STA).

Wireless radio links are highly unreliable.

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

a. Wireless LAN can have actively changing topologies

b. WLAN radio link signals are not protected from outside EM interference

c. WLAN radio links experience time-varying multipath effects.

d. WLANS have neither absolute nor observable boundaries.

WLAN required handling both mobile and portable stations and dealing with battery

powered equipment.

MSs 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.*** (July -2012-10M,Dec-2010-10M)

1. Independent Basic Service Set Networks

2. Distribution System Concepts

3. Extended Service Set Networks

4. Integration of Wired and Wireless LANs



1. Independent Basic Service Set (BSS) Networks

• 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).

Architecture description:

o There is no backbone infrastructure and the network consists of at least two wireless

stations.

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

o The propagation boundary will exist but its exact extent and shape are subject to

many variables.

o Simulation software exists that can provide some reasonable estimates of RSS for

typical multi-floor architectural layouts and various building materials.

o 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.

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

relationship.

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

unlimited number of times.

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

BSS.

2. Distribution System (DS) Concepts

o It provides an extended wireless network consisting of multiple BSSs, the standard

allows for an architectural component known as the Distribution System (DS).

o Figure 9.3 shows a diagram of a distribution system and several access points serving

different BSSs.



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

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

o 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).

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

performing the STA function within the BSS.

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

o 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.

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

network.

3. Extended Service Set (ESS) Networks

o 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 9.4

o 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.

o 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.

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

portal.

o To integrate the 802.11 wireless LAN with a traditional 802.x wired LAN (see Figure

9.4) a portal or logical point must exist where medium access control (MAC) service

data units or MSDUs can enter the wireless LAN distribution system.

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

architecture and the existing wired LAN.

8.4. Wireless PANs / IEEE 802.15x

1. Introduction to IEEE 802.15x Technologies

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

short distance between private groupings of participant devices.

o The goal of standard was to provide an ultra-low complexity, cost, and power for

low-data-rate wireless connectivity among fixed, portable, and moving devices either

within personal operating space (POS).

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

o Popular WPAN technologies are Bluetooth, ZigBee are supporting applications for

use in both the commercial/industrial and consumer/home environments.



WIRELESS PAN APPLICATIONS AND ARCHITECTURE

Wireless PAN Applications

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

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

phones.

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

tablet computers

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

o Personal home storage

o Printers & scanners

o Interactive video gaming

o Home theater

o Exchanging information directly between PDAs

o Connecting a keyboard or mouse wirelessly to a desktop computer

Basic WPAN Characteristics *(Dec-2012-6M)

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

o Data rates (currently up to 55 Mb/s)

o Short time to connect (<1s)

o Peer to peer connectivity

o Designed to support low power portable devices

o Easy to use

Difference between WPAN and WLAN***:

o 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

1. WPAN power levels and coverage areas

A WLAN

o Power Level : Approximately 100 mw

o Coverage Distances : Approximately 100 Meters

o Mobility : It enables fixed or less mobility

o Access Points (AP): Need to be placed in optimized fixed locations

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



The WPAN:

o Power Level : Approximately 1mw

o Coverage Distances : Approximately few 10 meters

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

o A WPAN uses low power consumption to enable true mobility.

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

several devices to share data through the use of WPAN technology.

2. Media control techniques

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

single member of the PAN known as the master and the other member or members

of the ad hoc PAN function as slaves and it is interchangeable.

o It uses of a time-multiplexed slotted system.

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

the required bandwidth needs.

o The master is then able to regulate the bandwidth assigned to the various slave

personal devices based upon the required QoS requested.

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

supported.

o A WLAN device is required to maintain management information database (MB) to

facilitate end-to-end network operations of a larger infrastructure.

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

network-controllable state to provide this type of WLAN functionality.

3. Network life span or duration

o 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.

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

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

connectivity without any pre deployment activity necessary

Advantages and Disadvantages of WPAN

Advantages:

o Dynamic network setup

o Usually quick and relatively simple to set up

o WPAN enabled devices are usually portable

o Needs less technical skills to deploy than LANs or WLANs.



Disadvantages:

o Typically have a limited range

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

technologies

o Compatibility and interoperability issues

o Since small devices hardware upgrade is sometimes difficult.

o Devices with inbuilt WPAN technologies can be considerably more expensive than

devices without WPAN technologies.

Bluetooth WPAN Overview

Introduction

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

o Goal is to replace cables.

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

computers and other devices.

o The Bluetooth wireless technology comprises hardware, software and

interoperability requirements.

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

barriers

o The Bluetooth provides support for both asynchronous and synchronous

communications.

– Asynchronous channels for data transfer.

– Synchronous channels for telephony-grade voice communications.

Bluetooth Specification:

o Standard is IEEE 802.15.1

o Operate 2.4-GHz unlicensed ISM band.

o FHSS is employed to prevent interference and signal fading.

o Data rate of 1Mbps.

o Use low power – 30 to 100mA active current.

o Antenna power 0dbm (mW) to cover 10mts

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

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

o Use full-duplex operation using a TDD scheme.

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

o Data traffic can have a maximum asymmetric rate of 723.2 kbps between two

devices.



o Bidirectional, synchronous 64-kbps channels are able to support voice traffic

between 2 devices.

o Various combinations of asynchronous and synchronous traffic are allowed.

Bluetooth Packet Data Format:

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

o The figure below indicates that each packet consists of an access code, a header, and

a payload.

o Figure below (10.3) depicts Bluetooth wireless technology and the OSI model.



Bluetooth WPAN Ad Hoc Network Topologies *:(Jan-2015-8M, July-2014-7M, Dec-12-8M)

The two basic types network topologies.

1. Piconet

2. Scatternets.

1. Piconet structure:

o 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).

o 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.

o The piconet is defined by the frequency hopping scheme.

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

fashion and under the direct control of the master.

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

multipoint fashion.

o 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.

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

master in another situation.

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

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

o 48 bit ID is used for the devices identification in the piconet.

o The hopping pattern is determined by device ID.



2. Scatternet structure:

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

(see fig below-10.5)

o 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.

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

o The Device in scatternet in imply any routing capabilities

Integration of a Bluetooth WPAN with other LANS

o The integration of Bluetooth WPAN with other LAN is shown in fig 10.6

o 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.

o 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.



Components of the Bluetooth Architecture*** (July-2013-8M, July-2011-8M)

o Figure 10.7 below shows the Bluetooth protocol stack.

o 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.

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

specific protocols.

o The link manager protocol (LMP) and the Logical Link Control And

Adaptation(L2CAP) layer protocol are

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

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

application protocol (WAP).

Layer Description:

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

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

o Link manager: It is the protocol that handles link establishment b/w Bluetooth

devices which include authentication and encryptions.

o LLC and L2CAP: It is connection based communication protocol that implements

multiplexing. No flow control. But provide reliable base band link.

o Audio profile: It responsible for managing connection for Tx /Rx data from audio

devices.

o Control: For control signal generations for various activities.

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



8.5 Broadband Wireless MANs/IEEE 802.16x

Introduction WMAN/IEEE 802.16X Technologies

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

o These systems can be used to provide multiple types of data services to system

subscribers.

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

subscribers without wires.

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

prevents collisions.

The origin and evolution of IEEE 802.16x

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

effective broadband wireless products on a worldwide basis.

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

frequencies band of 10 to 66 GHz.

o Initially it is an expensive type of broadband access technology accepts in a few

isolated, scattered areas.

o 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.

o The original standard has been amended to include operation in the 2- to 11-GHz

frequency range in both licensed and unlicensed bands.

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

set.

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

802.16 standards:

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

o 802.16.2 (minimizing interference between coexisting WMANs.)

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

o 802.16b (5-6 Ghz)

o 802.16c (detailed system profiles)

o P802.16e (Mobile Wireless MAN)

Details of IEEE 802.16 and 802.16a Standards

o 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.



– 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).

o 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 WIRELESS MANS:*(July-2013-7M)

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

o 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.

o It provides the required bandwidth capacity since they are shared systems designed for

high-speed net access for the home user.

o WMAN technology could be best alternate for DSL technology.



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

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

o 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 or

apartment, or while in a moving vehicle.

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

IEEE 802.16 WMANS Typical Deployment

o WMAN base station is typically located on a tall building to provide an unobstructed or

line-of-sight path between the subscriber stations and the BS antennas.

o IEEE 802.16a physical layer standard provides for NLOS operation at frequencies

between 2-11 GHz. substantial BS antenna heights is still desired because the best

system operation with the highest possible data transfers rates.

o A data rate is dependent upon BS to subscriber station radio channel characteristics.

o 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.

o For LOS operation, a typical cell radius for a wireless MAN system with the BS antenna at

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

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

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

formats used.

o 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.

o 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.

Wireless MAN 4×4 Antenna Sectoring Scheme*(Jan-2015-6M)

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

antenna sectors.

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

o Figure 11-2 illustrates the use of a rather complex, high-capacity, four by four-sector

system that provides four-frequency, four-sector frequency reuse.

o As shown in the figure11.2, four different frequency channels are used within every

sector. There are four, 90-degree sectors.

o Total of sixteen separate sectors (of 22.5 degrees each) can be supported, with

numerous subscriber stations per sector.



o For This configuration, the BS would consist of sixteen radio transceivers and sixteen

individual sector antennas that would have narrow fan-beam/pencil-beam type

radiation patterns.

o For this example, each one of the sixteen sectors could support the same total data

rate that a single Omni-directional BS could.

o It would be likely that the service provider would need to employ some form of fiber-

optic transport/connection to the network to support the total aggregated system

bandwidth to and from the BS.

Prepared By:

Prof.Suresha V.

Dept of E&C, KVG College of Engineering,Sullia.

Email:[email protected].

Cell No: +91 94485 24399.

Date: 17-04-2015

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