Fig 1 shows schematic for WI-MAX Technology .It stands for World Interoperability for Micro-wave Access. WiMAX is optimized for IP-based high-speed wireless broadband which will provide for a better mobile wireless broadband Internet experience.
Features of WI-MAX Technology :
1. Wi MAX can typically support data rates from 500 kbps to 2 Mbps.
2. WiMAX also has clearly defined QoS classes for applications with different requirements such as VoIP, real-time video streaming, file transfer, and web traffic.
3. A cellular architecture similar to that of mobile phone systems can be used with a central base station controlling downlink/uplink traffic.
4 WiMAX is a family of technologies based on IEEE 802.16 standards.
5. Two main types of WiMAX, fixed WiMAX (point-to- multipoint Technology) and mobile WiMAX (multipoint-to-multipoint technology).
6. WiMAX uses orthogonal frequency division multiple access (OFDMA) technology which has inherent advantages in, spectral efficiency, advanced antenna performance, and improved multipath performance.
7. Mobile devices connected directly can achieve a range of 4 to 6 miles.
8. Frequency band -2 to 11 GHz (unlicensed).
9. channel bandwidth: 1.25 MHz to 20 MHz.
Some of the salient features supported by WiMAX are
• High data rates. The inclusion of multi-input multi-out (MIMO) antenna Techniques along with flexible sub-channelization schemes, advanced coding and modulation all enable the mobile WiMAX technology to support peak downlink data rates of 63 Mbps per sector and peak uplink data rates of up to 28 Mbps per sector in a 10 MHz channel.
• Quality of service (QoS). The fundamental premise of the IEEE 802.16 MAC architecture is QoS.
• Scalability. Mobile WiMAX is designed to be able to scale to work in different Channelization from 1.25 to 20 MHz to comply with varied worldwide requirements as efforts proceed to achieve spectrum harmonization in the longer term.
• Security. Support for a diverse set of user credentials exists including SIM/ USIM cards, smart cards, digital certificates, and user name/password.
• Mobility. Mobile WiMAX supports optimized handoff schemes with latencies less than 50 ms to ensure that real-time applications such as VoIP can be performed without service degradation. Flexible key management schemes assure that security is maintained during handoff.
1. Single station can serve hundreds of users.
2. Speed of 10 Mbps at 10 kilometers with line-of-sight.
1. Line of sight is needed for longer connection.
2. Weather conditions like rain can interrupt the signal.
3 Other wireless equipment’s can interrupt the signal.
4 multiplied frequencies are used.