By, Shah Ankur Vasant

WIMAX stands for Worldwide Interoperability for Microwave Access The original IEEE standard (now called "Fixed WiMAX") was published in WiMAX adopted some of its technology from WiBro, a service marketed in Korea Its a communication technology for wirelessly delivering high- speed Internet service to large geographical areas  Geographical Area Coverage: 30 miles  Bandwidth: 75 Mbps  Frequency bands- 2 to 11 and 10 to 66 Ghz(licensed and unlicensed bands respectively)  Defines both MAC and PHY layer WiMAX

WiMax Over Wi-Fi Coverage Area: Below 100m for Wi-Fi Scalability Supports around 10 users Bitrate: 54 Mbps in 20 Mhz Channels Cost For Laying Cables throughout.

(Now withdrawn) basic standard released in 2001,provided high data links at 11 and 60 GHz frequencies a (Now withdrawn) Uses licensed frequencies from 2 to 11 GHz Supports Mesh Network b (Now withdrawn) Frequencies between 5 and 6 GHz Provided Quality of Service(QoS) Standards

802.16c (Now Withdrawn) Provided a system profile for operating between 10 and 66 GHz and provided more details for operations within this range Aim was to enable greater levels of interoperability d ( or Fixed WiMAX) Major revision of the standard Resulted in withdrawal of all previous standards Improvements to a including the use of 256 carrier OFDM Only addressed fixed operation. High Data Rates of 75 Mbps e ( or Mobile WiMAX) For nomadic and mobile use Lower data rates of 15 Mbps Enables full nomadic and mobile use including handover

Wireless access can be divided into three classes Stationary Pedestrian Vehicular Standards is classified into two types of usage models Fixed WiMAX Mobile WiMAX Types Of WiMAX

IEEE Current Standard for using fixed WiMax 3.5 GHz and 5.8 GHz frequency bands Frequency division duplexing (FDD) Time division duplexing (TDD) IEEE e extension to the supports mobile communications 2.3 and 2.5 GHz frequency bands.

802.16d802.16e SpectrumBelow 11 GHzBelow 6GHz Bit Rate Up to 20MHz Channel Up to 5MHz Channel Modulation OFDM 256 Sub-Carrier QPSK,16QAM,64QAM Scalable OFDMA MobilityFixedFixed and Mobile Channel Bandwidth Selectable Channel Bandwidths between MHz MHz Cell Radius 3-5 Miles Depends on tower height, power etc. 1-3 Miles

1.WiMAX Base Station (BS) Base Station is similar to a cellphone tower and Covers A radius of 30miles(3000 SqFt) 2.WiMAX receiver (WiMAX CPE) Customer Premise Equipment Receiver could be a small box or PCMCIA card, or they could be built into a laptop A WIMAX system consists of

Fixed WiMAX

P2P Point to Point P2MP Point to Multi Point Mesh Network WiMAX Network Architecture

P2P and P2MP

Mesh

Non-Line-Of-Sight : WiFi sort of service, where a small antenna on your computer connects to the tower uses a lower frequency range -- 2 GHz to 11 GHz Lower-wavelength transmissions are not as easily disrupted by physical obstructions -- they are better able to diffract or bend around obstacles. Line-Of-Sight : fixed dish antenna points straight at the WiMAX tower from a rooftop or pole stronger and more stable Allows to send a lot of data with fewer errors Uses High Frequencies, ranges reaching 66 Mhz Less Interference and More Bandwidth Modes Of Operation

Protocol Layers Of WiMAX Protocol Architecture has 4 layers: Convergence, MAC, Transmission and physical, which can be map to two OSI lowest layers: physical and data link ConvergenceMedium Access ControlTransmissionPhysicalOSI Data Link LayerOSI Physical Layer

MAC Protocol: Convergence sub-layer: Handle the higher-layer protocols Common part sub-layer: Channel access, connection establishment and maintenance & QoS Security sub-layer: Authentication, secure key exchange and encryption Physical and transmission layer functions: Encoding/decoding of signals Preamble generation/removal Bit transmission/reception Protocol Architecture

Physical Layer Features: Frequency Band Channel Bandwidth MIMO FDD/TDD Signal Modulation: Data Link Layer Features: access protocol, security and session establishment functions.

WiMAX PHY Frame

Scalability Quality of Service Range Coverage Features Of WiMAX

Faster than broadband service No need to lay cables thus reducing cost Easier to extend to Sub-Urban and rural areas Much Wider coverage Can use licensed spectrum Provides data, telecommunication services and portability. Advantages of WiMAX

Lack of Quality Low bit rate over Long distance Speed of connectivity Sharing of bandwidth WiMax over Wi-Fi Expensive network Bad Weather Power consuming Disadvantages