02-03-2011, 03:45 PM
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WiMAX
There have been many news recently about BSNL and Tata setting up WiMAX in India.
WiMAX stands for Worldwide Interoperability for Microwave Access. It is a telecommunications technology providing wireless data over long distances in a variety of ways, from point-to-point links to full mobile cellular type access. It is based on the WirelessMAN (IEEE 802.16) standard.
The current WiMAX revision provides up to 40 Mbps[1][2] with the IEEE 802.16m update expected offer up to 1 Gbit/s fixed speeds. (WiMAX is based on the IEEE 802.16 standard, also called Broadband Wireless Access). The name "WiMAX" was created by the WiMAX Forum, which was formed in June 2001 to promote conformity and interoperability of the standard. The forum describes WiMAX[3]as "a standards-based technology enabling the delivery of last mile wireless broadband access as an alternative to cable and DSL"
WiMAX base station equipment with asector antenna and wireless modem on top
A pre-WiMAX CPE of a 26 km (16 mi) connection mounted 13 metres (43 ft) above the ground .
Comparison with Wi-Fi
Comparisons and confusion between WiMAX and Wi-Fi are frequent because both are related to wireless connectivity and Internet access.
WiMAX is a long range system, covering many kilometers, that uses licensed or unlicensed spectrum to deliver connection to a network, in most cases the internet.
Wi-Fi uses unlicensed spectrum to provide access to a local network.
Wi-Fi is more popular in end user devices.
Wi-Fi runs on the Media Access Control's CSMA/CA protocol, which is connectionless and contention based, whereas WiMAX runs a connection-oriented MAC.
WiMAX and Wi-Fi have quite different quality of service (QoS) mechanisms:
W
iMAX uses a QoS mechanism based on connections between the base station and the user device. Each connection is based on specific scheduling algorithms.
Wi-Fi uses contention access - all subscriber stations that wish to pass data through a wireless access point (AP) are competing for the AP's attention on a random interrupt basis. This can cause subscriber stations distant from the AP to be repeatedly interrupted by closer stations, greatly reducing their throughput.
Both 802.11 and 802.16 define Peer-to-Peer (P2P) and ad hoc networks, where an end user communicates to users or servers on anotherLocal Area Network (LAN) using its access point or base station.
Wi-Fi and WiMAX are complementary. WiMAX network operators typically provide a WiMAX Subscriber Unit which connects to the metropolitan WiMAX network and provides Wi-Fi within the home or business for local devices (eg, Laptops, Wi-Fi Handsets, smartphones) for connectivity. This enables the user to place the WiMAX Subscriber Unit in the best reception area (such as a window), and still be able to use the WiMAX network from any place within their residence.
Connecting to WiMAX
A WiMAX Gateway which provides VoIP, Ethernet and WiFi connectivity.
A WiMAX USB modem for mobile internet.
There are numerous devices on the market that provide connectivity to a WiMAX network. These are known as the "subscriber unit" (SU).
There is an increasing focus on portable units, this includes handsets (similar to cellular smartphones), PC peripherals (PC Cards or USB dongles), and embedded devices in laptops, which are now available for Wi-Fi services. In addition, there is much emphasis from operators on consumer electronics devices such as Gaming consoles, MP3 players and similar devices. It is notable that WiMAX is more similar to Wi-Fi than to3G cellular technologies.
The WiMAX Forum website provides a list of certified devices. However, this is not a complete list of devices available as certified modules are embedded into laptops, MIDs (Mobile internet devices), and other private labeled devices.
WiMAX Gateways
WiMAX gateway devices are available as both indoor and outdoor versions from several manufacturers. Many of the WiMAX gateways that are offered by manufactures such as Zytel, Motorola, and GreenPacket are stand-alone self-install indoor units. Such devices typically sit near the customer's window with the best WiMAX signal, and provide:
A integrated Wi-Fi access point to provide the WiMAX Internet connectivity to multiple devices throughout the home or business.
Ethernet ports should you wish to connect directly to your computer or DVR instead.
One or two PSTN telephone jacks to connect your land-line phone and take advantage of VoIP.
WiMAX Dongles
There are a variety of USB dongles on the market which provide connectivity to a WiMAX network. Generally these devices are connected to a notebook or net book whilst on the go. Dongles typically have omnidirectional antennae which are of lower-gain compared to other devices, as such these devices are best used in areas of good coverage.
WiMAX Mobiles
HTC released the first WiMAX enabled mobile phone, the EVO 4G, March 23, 2010 at the CTIA conference in Las Vegas. According to Sprint, the device will be available Summer 2010 and will be capable of both EV-DO(3G) and WiMax (4G).. A number of WiMAX Mobiles are expected to hit the market in 2010.
Associations
WiMAX Forum
The WiMAX Forum is a non profit organization formed to promote the adoption of WiMAX compatible products and services.
A major role for the organization is to certify the interoperability of WiMAX products. Those that pass conformance and interoperability testing achieve the "WiMAX Forum Certified" designation, and can display this mark on their products and marketing materials. Some vendors claim that their equipment is "WiMAX-ready", "WiMAX-compliant", or "pre-WiMAX", if they are not officially WiMAX Forum Certified.
Another role of the WiMAX Forum is to promote the spread of knowledge about WiMAX. In order to do so, it has a certified training program that is currently offered in English and French. It also offers a series of member events and endorses some industry events.
WiMAX Spectrum Owners Alliance
WiSOA logo
WiSOA was the first global organization composed exclusively of owners of WiMAX spectrum with plans to deploy WiMAX technology in those bands. WiSOA focussed on the regulation, commercialisation, and deployment of WiMAX spectrum in the 2.3–2.5 GHz and the 3.4–3.5 GHz ranges. WiSOA merged with the Wireless Broadband Alliance in April 2008.