But what about fixed WiMAX? Worldwide Interoperability for Microwave Access (WiMAX) was originally introduced in October 2001 as the IEEE 802.16 standard, defining the air interface or PHY layer, as well as the MAC (Media Access Control) layer. The fixed WiMAX standard, 802.16d-2004, was released three years later, allowing non line of sight connections and setting OFDM as the transmission protocol.

 

There's been much talk that fixed WiMAX has a range of seventy or eighty miles, offering speeds of 48Mbps or more, but in reality bandwidth drops rapidly with range. So where fixed WiMAX has been or is planned to be deployed, it's generally over a range of up to about ten miles, offering connections similar to DSL, T1 leased lines or even T3s. Its uses have been mainly as an alternative "last mile" broadband connection to homes or offices, and as a backhaul connection for Wi-Fi hotspots and even 3G base stations.

 

Whatever the applications, sales of WiMAX equipment are growing strongly, albeit from a low base. WiMAX equipment sales hit $142.3 million last year, according to CA-based research house Infonetics, with a five year unit combined annual growth rate forecast at 139% between 2005 and 2009.

 

As a "last mile" connection to the Internet, fixed WiMAX can offers a number of advantages over a leased line or DSL alternatives. In some buildings in large cities there is no copper available to provide DSL, and a T1 line can take too long to get up and running. A WiMAX connection can in theory be installed by mounting a dish in a matter of hours.

 

WiMAX has the obvious drawback that it is not available everywhere, but in some parts of selected cities such as New York, Chicago, Boston, Los Angeles and San Francisco it is available. The evidence from users here is that where it is available it works well and is cheaper than more conventional connection methods.

 

"We have a T1 capacity WiMAX connection and we pay about one half of what we used to pay for a conventional T1 connection from our telco, and it's much more reliable," says Jim Sulley, principal at New York based media library Newscast. The company gets its WiMAX connection from a base station on the Empire State Building operated by MA-based TowerStream. One of the advantages of WiMAX is that service providers like TowerStream can deliver it at arbitrary bandwidths, instead of discrete capacities such as T1 or T3. This means that if a customer like Newscast has a need for more bandwidth for a short period of time – for example a once weekly overnight offsite backup – the service can be "turned up" to 5Mbps.

 

"So essentially, we get 3 T1s when we need it for less than half the price of a T1," says Sulley. WiMAX is an interesting "last mile" solution, but it also looks extremely attractive as a WAN technology to link buildings on a campus, or offices on different sides of a city. Of course if two offices have WiMAX links to the Internet it's possible to set up a VPN between the two, but some WiMAX service providers like Canada-based Redline Communications sell equipment that enables high speed point to point connections over distances of several miles, and a theoretical range of up to about 50 miles.

 

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