WiMax is a wireless digital communications system, also known as IEEE 802.16, that is intended for wireless "metropolitan area networks". WiMax can provide broadband wireless access (BWA) up to 30 miles (50 km) for fixed stations, and 3 - 10 miles (5 - 15 km) for mobile stations. In contrast, the WiFi/802.11 wireless local area network standard is limited in most cases to only 100 - 300 feet (30 - 100m).
With WiMAX, WiFi-like data rates are easily supported, but the issue of interference is lessened. WiMAX operates on both licensed and non-licensed frequencies, providing a regulated environment and viable economic model for wireless carriers.
WiMAX can be used for wireless networking in much the same way as the more common WiFi protocol. WiMAX is a second-generation protocol that allows for more efficient bandwidth use, interference avoidance, and is intended to allow higher data rates over longer distances.
The IEEE 802.16 standard defines the technical features of the communications protocol. The WiMAX Forum offers a means of testing manufacturer's equipment for compatibility, as well as an industry group dedicated to fostering the development and commercialization of the technology.
WiMax.com provides a focal point for consumers, service providers, manufacturers, analysts, and researchers who are interested in WiMAX technology, services, and products. Soon, WiMAX will be a very well recognized term to describe wireless Internet access throughout the world.
The race is on in the service provider community to offer "triple play" (voice, video and data) or "quadruple play" (voice, video data as well as mobile voice and data). Some ser-vice providers are attempting to do this with 3 or 4 dissimilar networks as illustrated in the figure below. For example, at the time of this writing, Qwest Communications Inter-national sold their own voice and broadband data for the residential market, Dish Net-works for satellite TV and resells Sprint Nextel cellular service. Reselling other service providers services does not generate the profit margins as selling one's own services does. Given the vertical orientation of legacy systems like cable TV (only does TV), circuit-switched voice services (like cell phone networks-designed almost entirely for voice), it is difficult and expensive to offer more than one type of service on any one "stovepipe" network. The solution is IP Multimedia Subsystems (IMS).
IMS Vision: The vision for IMS is that an all-IP network will allow a subscriber to access a multitude of services regardless of how they access the network (cable TV modem, DSL, cellular, Wi-Fi, or WiMAX). Very simply put, the subscriber will be able to access any service on any device
IMS began as a concept in the cell phone industry to offer voice, short messaging service (SMS) and video on cell phones. It utilizes a simple three-layer architecture consisting of the Connectivity Layer (similar to the physical layer in the OSI model), a Control Layer, which provides switching and signaling functions, and the Service Layer where applica-tions such as IPTV and VoIP features are offered. Running parallel to those function layers are a range of support systems, which control security and QoS across the network. The signaling protocol known as Session Initiation Protocol (SIP) provides signaling across the network.
Fixed Wireless (IEEE 802.16-2004) Applications: Perhaps the most lucrative application for WiMAX is that of substitute for the telephone company's copper wire. This is achieved through fixed wireless solutions. A majority of US businesses and residences receive their telephone service and internet access via the telephone company's copper wires. A T1 data line from the telephone company may re-tail for $800/month in many US cities. About 50% of that expense is "local loop" charges or paying to use the telephone company's copper wire to access a wider network. As the diagram below illustrates, a WiMAX service provider could purchase the bandwidth equivalent of a T1 (1.54 Mbps) at, say, $45 and resell to an enterprise customer for $400. Through oversubscription (overselling), that service provider could realize a multiple of that profit.