WiMAX

WiMAX (World Interoperability for Microwave Access) is an emerging technology that is designed to deliver fixed and more recently, mobile broadband connectivity. The WiMAX trade name is used to group a number of wireless technologies that have emerged from the IEEE (Institute of Electrical and Electronics Engineers) 802.16 Wireless MAN (Metropolitan Area Network) standards. The main two standards are identified as 802.16-2004 (October 2004) and 802.16e (December 2005) with 802.16e introducing mobility and currently receiving a great deal of interest in the telecoms world.
 * 4.0 WIMAX**

Typically, a WiMAX system consists of two parts:


 * A WiMAX Base Station: Base station consists of indoor electronics and a WiMAX tower. Typically, a base station can cover up to 10 km radius (Theoretically, a base station can cover up to 50 kilo meter radius or 30 miles, however practical considerations limit it to about 10 km or 6 miles). Any wireless node within the coverage area would be able to access the Internet.


 * A WiMAX receiver - The receiver and antenna could be a stand-alone box or a PCMCIA card that sits in your laptop or computer. Access to WiMAX base station is similar to accessing a Wireless Access Point in a WiFi network, but the coverage is more.

Several base stations can be connected with one another by use of high-speed backhaul microwave links. This would allow for roaming by a WiMAX subscriber from one base station to another base station area, similar to roaming enabled by Cellular phone companies.

Important Wireless MAN IEEE 802.16 (WiMAX) Specifications: - Range 30 miles (50 KM) radius from base station. - Non-Line-Of_Sight (NLoS) between user and base station. - Frequency bands; 2- 11GHz and 10 - 66GHz (licensed and unlicensed bands) - Defines both the MAC and Physical layer and allow multiple physical layer specification.




 * 4.1 Types Of WiMAX **

WiMAX is about ones of the broadband connectivity and in WiMAX, there have a types of it. The two types are Fixed WiMAX and Mobile WiMAX. Both of them are differenced by their way of connecting. What the interesting here is the broad range of applications it makes possible but not limited to broadband internet access, T1/E1 substitute for businesses, voice over Internet protocol (VoIP) as telephone company substitute, Internet Protocol Television (IPTV) as cable TV substitute, backhaul for WiFi hotspots and cell phone towers, mobile telephone service, mobile data TV, mobile emergency response services, wireless backhaul as substitute for fiber optic cable.


 * i. **** Fixed WiMAX **

WiMAX provides fixed, portable or mobile non-line-of sight service from a base station to a subscriber station, also known as customer premise equipment (CPE). Some goals for WiMAX include a radius of service coverage of 6 miles from a WiMAX base station for point-to-multipoint, non-line-of-sight (see following pages for illustrations and definitions) service. This service should deliver approximately 40 megabits per second (Mbps) for fixed and portable access applications. That WiMAX cell site should offer enough bandwidth to support hundreds of businesses with T1 speeds and thousands of residential customers with the equivalent of DSL services from one base station.



**i.** **Mobile WiMAX**

Mobile WiMAX takes the fixed wireless application a step further and enables cell phone-like applications on a much larger scale. For example, mobile WiMAX enables streaming video to be broadcast from a speeding police or other emergency vehicle at over 70 MPH. It potentially replaces cell phones and mobile data offerings from cell phone operators such as EvDo, EvDv and HSDPA. Meanwhile, Mobile WiMAX will operate in sub-6 GHz bands and support scalable channel bandwidths from 1.25 MHz to 20 MHz over SOFDMA (Scalable OFDMA) air interface. In addition to being the final leg in a quadruple play, it offers superior building penetration and improved security measures over fixed WiMAX. Mobile WiMAX will be very valuable for emerging services such as mobile TV and gaming.

**4.2** ** WiMAX Topologies **



__**WiMAX Evolution**__

__**IEEE Standard Family**__