WIMAX

Contents Ways of Access Internet Why We Use Wimax. What is Wimax Wimax Working Wimax Architecture Wimax Interfaces Wimax relationship with other

technologies Wimax Standards Wimax Advantages Wimax Uses

Three ways to access the Internet today….

Dial-up access : pay for a local call every time we dial the Internet. In addition phone line is engaged while we are on the Internet.

Broadband access : In your home, you have either a DSL or cable modem. At the office, your company may be using a T1 or a T3 line.

Wi-Fi access : In your home, you may have set up a Wi-Fi router that lets you search the Web while you are connecting with your laptop. On the road, you can find Wi-Fi hot spots in restaurants, hotels, coffee shops and libraries.

Why we use wimax

The main problems with broadband access are that it is more expensive and it doesn't reach all areas.

The main problem with Wi-Fi access is that hot spots (access point of wireless network) are very small, so coverage is small.

Due to these problems we are using advance technology called WIMAX

What is Wimax

WiMAX stands for Worldwide Interoperability of Microwave Access, is a wireless Internet service designed to cover wide geographical areas serving large number of users at low cost.

WiMax is a foundati on set on the IEEE 802.16 standards. However the name given to WiMax was suggested by WiMax Forum in 2001.WiMax technology is also termed as wireless broadband this is because it is believed that it can replace DSL cable network. Wimax defi ning wide area wireless data networking

WAN IEEE 802.16eIMT-2000(3G)(Nationwide)

MANIEEE 802.16-2004

WiMAX(50 Km)

LANIEEE 802.11

(150 m)

PANIEEE 802.15Bluetooth

(10m)

Typical Network Ranges

Wide Area Network

Metropolitan Area Network

Local Area Network

Personal Area Network

A WiMAX system consists of two parts

TRANSMITTER A single WiMAX tower can provide coverage to a very large area – as big as 3,000 sq. miles.

RECEIVER The receiver and antenna could be a small box or PCMCIA card or they could built into a laptop as the way Wi-Fi access is today.

HOW DOES IT WORK ?

WiMAX uses microwave radio technology to connect computers to the internet in place of wired connections such as DSL or cable modems.

It works very much like cell phone technology in that reasonable proximity to a base station is required to establish a data link to the Internet.

Users within 3 to 5 miles of the base station will be able to establish a link using NLOS technology with data rates as high as 75 Mbps.

Users up to 30 miles away from the base station with an antenna mounted for LOS to the base station will be able to connect at data rates approaching 280 Mbps.

Wimax Network Architecture

WiMAX network architecture comprises three major elements or

areas

Remote or Mobile stations: These are the user equipments that may be mobile or fixed and may be located in the premises of the user.

Access Service Network (ASN ): This is the area of the WiMAX network that forms the radio access network at the edge and it comprises one or more base stations and one or more ASN gateways.

Connectivity Service Network (CSN): This part of the WiMAX network provides the IP connectivity and all the IP core network functions. It is what may be termed the core network in cellular parlance.

The overall WiMAX network comprises a number of different entities that make up the different major areas described above. These include the following entities.

Subscriber Station (SS) / Mobile Station(MS) : 

The Subscriber station, SS may often be referred to as the Customer Premises Equipment, CPE. 

Base Station (BS) :  The base-station forms an essential element of the WiMAX

network. It is responsible for providing the air interface to the subscriber and mobile stations.

Authentication, Authorization and Accounting Server, AAA:  

As with any communications or wireless system requiring subscription services, an Authentication, Authorization and Accounting server is used. This is included within the CSN.

ASN Gateway (ASN-GW):   The ASN gateway within the WiMAX network architecture

typically acts as a layer 2 traffic aggregation point within the overall ASN.

The ASN-GW may also provide additional functions that include: intra-ASN location management and paging, radio resource management and admission control, caching of subscriber profiles and encryption keys.

Home Agent, HA:   The Home Agent within the WiMAX network is located within

the CSN. With Mobile-IP forming a key element within WiMAX technology, the Home Agent works in conjunction with a "Foreign Agent", such as the ASN Gateway, to provide an efficient end-to-end Mobile IP solution. The Home Agent serves as an anchor point for subscribers, providing secure roaming with QOS capabilities.

Interfaces of wimax R1—Represents the interface between the wireless device

and the base station. R2—Represents the link between the MS (mobile station)

and the CSN (connectivity service network). R3—Represents the link between the ASN (access service

network) and the CSN. R4—Represents the link between an ASN and another

ASN. R5—Represents the link between a CSN and another CSN. R6—Located within an ASN and represents a link between

the BS (base station) and the ASN-GW. R7—Located within the ASN-GW and represents internal

communication within the gateway. R8—Located within an ASN and represents a link between

two base stations.

Forms of Wireless Service

NLOS (Non Line of Sight) There is the non-line-of-sight, where a small antenna on your

computer connects to the tower. In this mode, WiMAX uses a lower frequency range -- 2 GHz to 11 GHz (similar to Wi-Fi). Lower-wavelength transmissions are not as easily disrupted by physical obstructions -- they are better able to diffract, or bend, around obstacles.

LOS ( Line of Sight) There is line-of-sight service, where a fixed dish antenna

points straight at the WiMAX tower from a rooftop or pole. The line-of-sight connection is stronger and more stable, so it's able to send a lot of data with fewer errors.

Line-of-sight transmissions use higher frequencies, with ranges reaching a possible 66 GHz. At higher frequencies, there is less interference and lots more bandwidth.

3G Mobile Wi-Fi WiMAX

Max. Speed 2 Mbps 16 Mbps 54 Mbps 100 Mbps

Coverage Several Miles Several Miles 300 feet 50 miles

Airwave Licensed Licensed Unlicensed Either

Advantages Range, Mobility

Speed, Mobility Speed, Price Speed,

Range

Disadvantages

Slow, Expensive High Price Short Range Interference

issues

Relationship with other Wireless Technologies

WIMAX SPECTRUMWiMax Forum is focusing on 3 spectrum bands for

global deployment:

Unlicensed 5 GHz: Includes bands between 5.25 and 5.85 GHz. In the upper 5 GHz band (5.725 – 5.850 GHz) many countries allow higher power output (4 Watts) that makes it attractive for WiMax applications.

Licensed 3.5 GHz: Bands between 3.4 and 3.6 GHz have been allocated for BWA in majority of countries.

Licensed 2.5 GHz: The bands between 2.5 and 2.6 GHz have been allocated in the US, Mexico, Brazil and in some SEA countries. In US this spectrum is licensed for MDS and ITFS.

WiMax Standards

802.16 802.16a 802.16-2004

802.16e-2005

Date Complete

d

December 2001

January 2003

June 2004

December 2005

Spectrum 10-66 GHz < 11 GHz

< 11 GHz

< 6 GHz

Operation LOS Non-LOS Non-LOS

Non-LOS and Mobile

Bit Rate 32-134 Mbps

Up to 75 Mbps

Up to 75 Mbps

Up to 15 Mbps

Cell Radius

1-3 miles 3-5 miles 3-5 miles

1-3 miles

What are the Advantages

A Single WiMAX main Station can serve hundreds of users. Endpoints install within days instead of the weeks required for wired

connections. Data rates as high as 280 Mbps and distances of 30 miles are possible. Users can operate mobile within 3-5 miles of a base station at data rates

up to 75 Mbps. No FCC radio licensing is required. Less expensive than DSL or coaxial cable.

What are the disadvantages

Line-of-Sight is required for long distance (5-30 mile) connections. Heavy rains can disrupt the service. Other wireless electronics in the vicinity can interfere with the WiMAX connection and cause a reduction in data throughput or even a total disconnect.

Uses of Wimax

Connecting Wi-Fi hotspots with each other and to other parts of the internet.

Providing a wireless alternative to cable and DSL for last km broadband access.

Providing a high-speed mobile data and telecommunications services (4G).

Providing a diverse source of Internet connectivity as a part of business continuity plan.

Providing Nomadic (mobile) connectivity.

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