CS426

Prof.Vicky Hsu 

PROJECT ON WiMAXBY

MOHAMMED IMRANA1561

 

2

WiMAX

Worldwide Interoperability for Microwave Access

ContentsIntroductionWorking of WIMAXIEEE 802.16 standard802.16 ArchitectureIEEE 802.16 SpecificationsWiMAX Development StagesFeatures of WIMAXAdvantages & Disadvantages of WiMAXAdvantages of WIMAX over WIFIWIMAX vs. 3GFUTURE OF WIMAX

Brief on WiMAX

WiMAX is an acronym that stands for Worldwide Interoperability for Microwave Access, a certification mark for products that pass conformity and interoperability tests for the IEEE 802.16 standards.

WiMAX is a standards-based wireless technology that provides high-throughput broadband connections over long distances.

WiMAX can be used for a number of applications, including "last mile" broadband connections, hotspots and cellular backhaul, and high-speed enterprise connectivity for business.

Why WiMAX?

There are three possible ways to access internet.Broadband access

Uses DSL or cable modem at home and T1 or T3 line at office

WIFIUses WIFI routers at home and hotspots on the road

Dial Up Connection

NEW TECHNOLOGY

Broadband access is too expensive and WiFi coverage is very sparse.

The new technology promisesHigh speed of broadband serviceWireless rather than wired accessBroad Coverage

HISTORY OF WIMAX

WiMAX technology was developed in earlier 2000 and it was named by WiMax Forums. In year 2004 this technology started to groom and eventually gets into lots of talk’s and  discussions around the world among major international institutes, in year 2004 advancements, enhancements were deployed to some extend.

WiMAX has not yet deployed to its full potential and still lot and lots of room to use this technology to its potential. It is not yet put to use as commercialized technologies like Wifi, GPRS, and 3G.

Businesses and governments are looking at the development of WiMax in their areas. There is also currently a high level of interest in the development of mobile applications for WiMax.

The WIMAX Forum Founded in April 2001

No Profit organization comprised of wireless access system manufacturers, component suppliers, software developers and carriers.

A wireless industry consortium that supports and promotes WiMAX’s commercial usage.

Comply with the WiMAX standard and focus on the interoperability.

Members include Intel, AT&T, Siemens Mobile, British Telecommunications, etc.

1) A WiMAX tower, similar in concept to a cell-phone tower - A single WiMAX tower can provide coverage to a very large area as big as 3,000 square

miles (~8,000 square km).

2) A WiMAX receiver - The receiver and antenna could be a small box or Personal Computer Memory card, or they could be built into a laptop the way WiFi access is today

A WIMAX system consists of

HOW WIMAX works?

MODES OF OPERATION

Line-of-sight service Line-of-sight between transmitter & receiver 11 GHz to 66 GHz frequency range At Higher frequencies, there is less interference and lots more

bandwidth.

Non-line-of-sight Line-of-sight is not required in between a small antenna on CPE

and receiver 2 GHz to 11 GHz frequency range• Longer-wavelength transmissions are not as easily disrupted by physical obstructions – they are better able to diffract, or bend, around obstacles .

WIMAX Scenario

Consider a scenario where a WiMax-enabled computer is 10 miles away from the WiMax base station.

A special encryption code is given to computer to gain access to base station

The base station would beam data from the Internet required for computer (at speeds potentially higher than today's cable modems)

WIMAX Scenario

The user would pay the provider monthly fee for using the service. The cost for this service could be much lower than current high-speed Internet-subscription fees because the provider never had to run cables

The WiMAX protocol is designed to accommodate several different methods of data transmission, one of which is Voice Over Internet Protocol (VoIP)

If WiMAX-compatible computers become very common, the use of VoIP could increase dramatically. Almost anyone with a laptop could make VoIP calls

WIMAX CHIPSWiMAX Mini-PCI Reference Design Intel’s first WIMAX chip

IEEE 802.16

Range- 30 miles from base stationSpeed- 70 Megabits per secondFrequency bands- 2 to 11 and 10 to

66(licensed and unlicensed bands respectively)

Defines both MAC and PHY layer and allows multiple PHY layer specifications

Usage Models of IEEE 802.16

Fixed IEEE 802.16 standard

Portable IEEE 802.16-2004 standard ( revises & replaces IEEE

802.16a & 802.16REVd versions) Mobile

IEEE 802.16e

IEEE 802.16 Specifications 802.16a

Uses the licensed frequencies from 2 to 11 GHz

Supports Mesh network 802.16b

Increase spectrum to 5 and 6 GHz

Provides QoS( for real time voice and video service) 802.16c

Represents a 10 to 66GHz 802.16d

Improvement and fixes for 802.16a 802.16e

Addresses on Mobile

Enable high-speed signal handoffs necessary for communications with users moving at vehicular speeds

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802.16/c 802.16a/REVd/2004 802.16e

Spectrum 11-66 GHz 2-11 GHz 2-6 GHz

Channel Conditions

LOS LOS, NLOS NLOS

Bit Rate 32-124 Mbps 1-70 Mbps Up to 50 Mbps

Modulation QPSK, 16QAM and 64QAM OFDM 256 sub-carriers, QPSK, 16QAM and 64QAM

SOFDMA

Mobility Fixed Fixed, Portable Mobile (upto 120Km/h)

Channel Bandwidths

20, 25 and 28 MHz Selectable channel bandwidths between 1.5 and 20 MHz

Selectable channel bandwidths between 1.25 and 20 MHz

Typical Cell Radius

1-3 miles 3-5 miles

Maximum range 30 miles based on the tower height

1-3 miles

WiMAX Standards

WiFiWiFi

WiFiWiFi

802.16eNLOS to MSS (laptop/PDA.)

802.16aNLOS to fixed

outdoor antenna

802.16aNLOS to

fixed Indoor antenna

802.16LOS to fixed

outdoor antenna

Broadband Wireless Access

WiFiWiFi

MSS: Mobile Subscriber Station; LOS: Line of Sight; NLOS: Non Line of Sight

802.16/a Backhaul

802.16 Architecture IEEE 802.16 Protocol Architecture has 4 layers: Convergence, MAC,

Transmission and physical, which can be mapped to two OSI lowest

layers: physical and data link.

802.16 Architecture

P2MP ArchitectureBS connected to Public Networks

BS serves Subscriber Stations (SS)

Provides SS with first mile access to Public Networks

Mesh ArchitectureOptional architecture for WiMAX

P2MP Architecture

Mesh Architecture

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802.16 Network Topology

WiMAX Development Stages Fixed Wireless:

• Phase 1: Fixed wireless access using outdoor installed antennae providing high speed service to businesses. Also, will serve in a “backhaul” role, linking WiFi hot spots to the Internet.

• Phase 2: Introduction of indoor, self-installable Customer Premises Equipment (CPE). Consumers will be able to bring home a box resembling a cable modem, plop it down anywhere in the house and receive high speed service.

Mobile Wireless: Phase 3: Manufacturers to integrate WiMAX into PC

cards, laptops, and other portable devices to enjoy high speed connectivity at home, around town, and even while speeding down the highway.

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FEATURES OF WIMAX

Long Range

Scalability

Quality of Service

Coverage

LONG RANGEOptimized for up to 50 Km

Designed to handle many users spread out over kilometres

Designed to tolerate greater multi-path delay spread (signal reflections) up to 10.0μ seconds

PHY and MAC designed with multi-mile range in mind

SCALABILITYThe 802.16 standard supports flexible

radio frequency (RF) channel bandwidths.

The standard supports hundreds or even thousands of users within one RF channel

As the number of subscribers grow the spectrum can be reallocated with process of sectoring.

Quality of Service

Primary purpose of QoS feature is to define transmission ordering and scheduling on the air interface

These features often need to work in conjunction with mechanisms beyond the air interface in order to provide end to end QoS or to police the behaviour or SS.

Requirements for QoS

A configuration and registration function to pre configure SS based QoS service flows and traffic parameters.

A signalling function for dynamically establishing QoS enabled service flows and traffic parameters.

Utilization of MAC scheduling and QoS traffic parameters for uplink service flows.

Utilization of QoS traffic parameters for downlink service flows.

Coverage

Standard supports mesh network topology

Optimized for outdoor NLOS performance

Standard supports advanced antenna techniques

WiMAX Applications

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WiMAX Applications (Contd.) Cellular backhaul Uses PTP antennas to connect aggregate subscriber

stations to each other and to base stations across long distances.

Last mile Uses PMP antennas to connect residential or business

subscribers to the BS.

Broadband ‘On-demand’It enables the service provider to offer instantly configurable high speed connectivity for temporary events.

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WiMAX Applications (Contd.)

Residential broadband: filling the gaps in cable & DSL coverage The range, absence of a LOS requirement, high BW, flexibility and low cost helps to

overcome the limitations of traditional wired and proprietary wireless technologies.

Underserved Areas Local utilities and governments work together with a local Wireless Internet Service

Provider (WISP) to deliver service.

 Mobility IEEE 802.16e allow users to connect to a WISP even when they roam outside their home or

business, or go to another city that also has a WISP.

BENEFITS OF WIMAX

Speed Faster than broadband service

WirelessNot having to lay cables reduces costEasier to extend to suburban and rural areas

Broad CoverageMuch wider coverage than WiFi hotspots

Benefits to Service Providers

Allow service providers to deliver high throughput broadband based services like VoIP, high-speed Internet and Video.

Facilitate equipment compatibility.

Reduce the capital expenditures required for network expansion.

Provide improved performance and extended range.

Benefits to Customers

Range of technology and service level choices from both fixed and wireless broadband operators.

DSL-like services at DSL prices but with portability.

Rapidly declining fixed broadband prices.

No more DSL “installation” fees from incumbent.

Disadvantages of WiMAX

Line-of-sight (LOS) is required for long distance (5-30 mile) connections.

Certain conditions —terrain, weather and large buildings—can act to reduce the maximum range.

Other wireless electronics can interfere with the WiMAX connection & cause a reduction in data throughput.

licensed airwave frequencies are limited availability. Unlicensed airwaves are free but all can use them—difficult to control service quality as other users of the same band could cause interference

Comparison betweenWi-Fi & WiMAX

(IEEE 802.11 & IEEE 802.16a)

Scalability

• Channel bandwidths can be chosen by operator (e.g. for sectorization)

• 1.5 MHz to 20 MHz width channels. MAC designed for scalability. independent of channel bandwidth

• MAC designed to support thousands of users.

• Wide (20MHz) frequency channels

• MAC designed to support 10’s of users

802.16a802.11

802.16a is designed for subscriber density

5.0 bps/Hz100 Mbps1.5 – 20 MHz802.16a

2.7 bps/Hz54 Mbps20 MHz802.11

Maximum bps/Hz

Maximum Data Rate

Channel Bandwidth

RELATIVE PERFORMANCE

802.16a is designed for metropolitan performance

Quality of Service

• Grant-request MAC

• Designed to support Voice and Video from ground up

• Supports differentiated service levels: e.g. T1 for business customers; best effort for residential.

• Centrally-enforced QoS

• Contention-based MAC (CSMA/CA) => no guaranteed QoS

• Standard cannot currently guarantee latency for Voice, Video

• Standard does not allow for differentiated levels of service on a per-user basis

• 802.11e (proposed) QoS is prioritization only

802.16a802.11

High Quality of Service

Range

• Optimized for up to 50 Km

• Designed to handle many users spread out over kilometers

• Designed to tolerate greater multi-path delay spread (signal reflections) up to 10.0μ seconds

• PHY and MAC designed with multi-mile range in mind

• Optimized for ~100 meters

• No “near-far” compensation

• Designed to handle indoor multi-path delay spread of 0.8μ seconds

• Optimization centers around PHY and MAC layer for 100m range

802.16a802.11

802.16a is designed for distance

Coverage

• Optimized for outdoor NLOS performance

• Standard supports mesh network topology

• Standard supports advanced antenna techniques

• Optimized for indoor performance

• No mesh topology support within ratified standards

802.16a802.11

Security

• Existing standard is PKM - EAP• Existing standard is WPA + WEP

• 802.11i in process of addressing security

802.16a802.11

802.16a maintains fixed wireless security

Advantages of WiMax over 3GUsing an assortment of proprietary and

standards-based technologies, such as OFDM and W-CDMA ,WiMax has a clear advantage over 3G

The advantages includeHigher ThroughputLow CostLower Latency

Advantages of WiMax over 3G

Advantages of WiMax over 3G

WiMax spectrum is more economical than 3G.The price paid per Hz is as much as 1000

times lower than for 3G spectrum

The low cost is a clear driver for service providers to enter the field of wireless services with WiMax

Advantages of WiMax over 3G

WiMAX is important for mobile broadband wireless, as it completes 3G by providing higher performance for data with more than 1 Mbps downstream to allow connection of laptops and PDAs

WiMAX technology is the solution for many types of high-bandwidth applications at the same time across long distances and will enable service carriers to converge the all-IP-based network for triple-play services data, voice, and video

Advantages of WiMax over 3G

WiMAX interoperable solutions enable economies of scale through integration of standard chipsets, making WiMAX Forum Certified products cost-effective at delivering high-capacity broadband services at large coverage distances in Line Of Sight and Non Line Of Sight conditions

ISSUES in 3G vs. WIMAX

Deployment of the networkWIMAX deployment is in the planning stages

and it might take 3-5 years in providing reasonable coverage in well populated areas

WiMax may initially be relegated to college campuses and larger corporate campuses where people are less mobile and costs containment is important

ISSUES in 3G vs. WIMAX

Quality of ServiceTo provide quality of service by deploying WIMAX

networks and to facilitate the continuous availability of service, careful planning is required at the edge of the network to manage network monitoring, availability, failover, routing etc

This can actually be done using outsourced services in cheap labor markets like India and China via the public Internet

ISSUES in 3G vs. WIMAXCost Issue

The main reason to opt for WIMAX is its low cost.

The price paid per Hz for WIMAX spectrum is as much as 1000 times lower than for 3G spectrum

The low cost of WIMAX spectrum compared to 3G is a clear driver for service providers to enter the field of wireless services with WIMAX

USES OF WIMAX

More ……

Promises

Conclusion (The Final Issue)

Will WIMAX replace 3G?Along with the forthcoming standardization, WiMAX has the

potential to substitute 3G and become a promising 4G

WiMAX has its distinct identity as either a stand-alone solution for incumbent and competitive fixed network operators or as complementary radio access solution for established 2G and 3G cellular network operators

Fixed-line operators, on the one hand, may consider WiMAX as a viable alternative to add mobility to the service portfolio, leveraging their huge subscriber base, in particular in countries where 3G licensing is delayed or not affordable

ONGOING RESEARCH:

QoS Mechanism for the Mesh Operating Mode of IEEE 802.16.

Cross-Layer Scheduling-Routing in the Mesh Mode of IEEE 802.16.

Increasing the Speed of the Bandwidth Allocation Mechanism of the Intranet Traffic in the Mesh Mode of IEEE 802.16.

Reducing the MAC Overhead in the PMP Operating Mode.

Performance Analysis of the Mobility Capability of IEEE 802.16e.

References

http://computer.howstuffworks.com/wimax.htm

www.winncom.com/proxim/proximwimax.aspx

www.dialaphone.co.uk/blog/?p=1833

www.techwarelabs.com/articles/other/wimax_wifi

www.wimaxforum.org

http://standards.ieee.org/catalog/olis/lanman.html