IEEE 802 Seminar Vijay Rathi Improved

8/8/2019 IEEE 802 Seminar Vijay Rathi Improved

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Guided By -:Dr.M.U.Kharat

IEEE 802.16a Standard and WiMAX

Igniting Broadband Wireless Access


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Content

y What isWiMAX?

y Introduction and Need.

y Overview of the IEEE 802.16a Standard.

y Interoperability Problem with standard.

y 802.16 Characteristics

y Air interfaces For 802.16a

y PHY layer Features

y MAC layer Features

y Compare with OtherWireless Technologies


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What is WiMAX?y WiMAX (Worldwide Interoperability for Microwave Access)

y BWA (BroadbandWireless Access) Solution.

y Standard (IEEE 802.16 is the standard) for constructingWireless

Metropolitan Area Networks (WMANs).

y Can go places where no wired infrastructure can reach.

y BackhaulingWi-Fi hotspots & cellular networks.

y Offers new and exciting opportunities to established and newly emerging

companies.


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Introduction and Need of 802.16

y The 802.16a standard Specifies a protocol .

y To Accelerate the Broadband Equipments market.

y Increase System performances and reliability for wireless

technologies.y Cover Lower Frequency Bands in Range 2-11GHz. For

NLOS.

y Market need of Alternative to Cables,DSL T1 level services.

y Support to Voices and Video Services.


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Overview of the IEEE 802.16a Standard.

y Absences of truly Global Standards .

y WLAN (802.11x) was not will Suited for outdoor BWA

Application.

yLimitation for Bandwidth and Subscribers and Range forWLAN.

y With the Analysis and review of IEEE(Working Group)

Come upWith Complex and developed Standards .

y With QoS and Last Mile Access Market.y Broad industry Support to Development of Standard Further.

y Came up with Carrier Class performances.


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Interoperability Problem with standard.

y Adoption of Standard is always a problem at Initial Stage.

y Product Should Interoperate.

y End Users can buy they like with features they want work

with alike certified products.y IEEE does not fulfill the interoperate problem leading to

mass Adoption.

y WiMAX leaded to Come up with this Problem.

y Events to test Interoperability for IEEE 802.16 ByWiMAX.


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802.16 Characteristics

y Point-to-multipoint broadband wireless access

y Operates in 10-66 GHz spectrum

y Data rates up to 134 Mbps

y Requires directional line-of-sight (LOS) propagation

y 802.16a adopted to address these concerns

y Operates in 2-11 GHz spectrum

y Eliminates need for directional LOS propagation

y

Greater range but lower data rates


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Air interfaces For 802.16a

y Major Changes to the PHY layer Specification

y The 2-11 GHz band specification is given in the IEEE

802.16a standard. Three types of air interfaces are supported

in this band:WirelessMAN SC2: uses a single carrier modulation format

WirelessMAN OFDM: uses OFDM with 256 point transform

WirelessMAN OFDMA: uses OFDM with 2048 point transform


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IEEE 802.16a PHY layer.


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Orthogonal Frequency Division Multiplexing(OFDM)

and single carrier Mode

y Multiplexing technique that divides the channel into multipleorthogonal sub channels

y Input data stream is divided into several sub streams of a lowerdata rate (increased symbol duration) and each sub stream ismodulated and simultaneously transmitted on a separate subchannel

y High spectral efficiency, resilient to interference, and low multi-path distortion

y Orthogonal frequency division multiplexing (OFDM) overcome

the challenges of NLOS propagation.y TheWiMAX OFDM waveform offers the advantage of being able

to operate with the larger delay spread.


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Orthogonal Frequency Division Multiple

Access (OFDMA)

y Multiple-access/multiplexing scheme

y multiplexing operation of data streams from multiple users

y Dynamically assign a subset of subchannels to individual users

y Wireless MAN-OFDMA based on scalable OFDMA

(SOFDMA)

y Support scalable channel bandwidths from 1.25 to 20 MHz


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802.16 PHY Block Diagram

Error Control

EncodingData Source

OFDM

Modulator

Wireless

Channel

BER TesterError Control

Decoding

Channel

Estimator

Channel

Equalizer

OFDM

Demodulator


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IEEE 802.16a MAC layer.


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802.16 MAC

y WirelessMAN operates at MAC sub-layer of Data Link Layer

y MAC layer is further subdivided into three layers

yConvergence sub-layer (CS)

y Common part sub-layer (CPS)

y Privacy sub-layer


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802.16 MAC:CS Layery Interoperability requires convergence sub-layer to be service

specific

y Separate CS layers for ATM & packet protocols

y CS Layer:

y Receives data from higher layers

y Classifies data as ATM cell or packet

y Forwards frames to CPS layer


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802.16 MAC:CPS Layery Performs typical MAC functions such as addressing

y Each SS assigned 48-bit MAC address

y Connection Identifiers used as primary address after initialization

yMAC policy determined by direction of transmissiony Uplink is DAMA-TDMA

y Downlink is TDM

y Data encapsulated in a common format facilitating interoperability

y Fragment or pack frames as neededy Changes transparent to receiver


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802.16 MAC: Privacy Sub-Layer

y Provides secure communication

y Data encrypted with cipher clock chaining mode of DES

y Prevents theft of service

y

SSs authenticated by BS using key management protocol


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IEEE 802.16 and WiMAX are designed as a

complimentary technology to Wi-Fi and Bluetooth


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WiMAX Applications


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IEEE 802.16 MAC commonly used

termsy BS Base Stationy SS Subscriber Station, (i.e., CPE)y DL Downlink, i.e. from BS to SSy UL Uplink, i.e. from SS to BS

y FDD Frequency Division Duplexy TDD Time Division Duplexy TDMA Time Division Multiple Accessy TDM Time Division Multiplexingy OFDM Orthogonal Frequency Division Multiplexingy OFDMA - Orthogonal Frequency Division Multiple

Accessy QoS Quality of Service


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References

y IEEE 802.16a Standard andWiMAX Igniting Broadband

Wireless Access, White Paper.

y WiMAXs technology for LOS and NLOS environments,

WiMAX Forum.y Carl Eklund, Roger B. Marks, Kenneth L. Stanwood, Stanley

Wang, IEEE Standard 802.16: A technical overview of the

WirelessMAN Air Interface for BroadbandWireless Access,

IEEECommunications Magazine, June 2002.


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Thank You

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IEEE 802 Seminar Vijay Rathi Improved