Unlike other wireless technology standards, WiMAX (Worldwide Interoperability for Microwave Access) covers several different frequency ranges. The IEEE 802.16 standard addresses frequencies from 10GHz to 66GHz, with the 802.16a specification adding coverage in the 2GHz-to-11GHz band.

The Last Mile Holy Grail

Every carrier and ISP/WISP has more bandwidth than they know what do to with in-house, and buying more is cheap in bulk.  The trouble is, all that cheap bandwidth is typically pouring into their POP, the trick is how to get it from the POP to clients premises without having to buy lease expensive copper or fiber circuits controlled by the Telco's or cable company.

Typically you either buy a circuit off the incumbent which consists of bonded copper pairs providing you with a spendy T-1, in some instances they will run fiber to your premises.  Failing that, you buy or lease a dedicated point to point radio or opt for a point to point optical solution.

If you want to be able to circumvent the bandwidth and price grip the Telco’s currently have, and deliver high-speeds securely and with VoIP-capable end to end QoS, then WiMAX is the next great hope.  And with the fast-growing global industry support, the price point for the CPE will drop dramatically much as it has with Wi-Fi.

The WiMAX Forum are concentrating on two critical bands for global adoption and therefore affordable mass production of the radio equipment, namely 2.5GHz (MMDS) and 3.5GHz which isn't available in the USA.

The WiMAX specification uses a 256-point orthogonal frequency division multiplexed (OFDM) carrier technology, giving it greater range than wireless LANs, which are based on 64-point OFDM. Another key difference of 802.16 is its use of time slots, allowing greater spectral efficiency for quality of service capabilities. The maximum data rate for 802.16 is higher than that of 802.11a/b, mainly because it gets nearly twice the number of bits per second from a single Hertz of frequency.

WiMAX supports ATM, IPv4, IPv6, Ethernet, and VLAN services thus offering a rich choice of service possibilities to voice and data carriers.  This is achieved by dividing different services into specific sub layers of the MAC. 

Security has been well thought out with authentication being handled as part of the common part sub layer with (PKI) X.509 digital certificates.  All 802.16a compliant devices will incorporate two unique certificates, one specific to the unit and one specific to the manufacturer of the unit thus promoting a secure and efficient way of authenticating upstream.

Many people in the industry continue to stretch 802.11 in an attempt to ‘evolve’ it into a WMAN solution.  My opinion is that the protocol doesn’t scale, there is no QoS in the MAC and the chosen RF bands simply do not have the capacity required to handle a nationwide network carrying anywhere near useful amounts of well-managed traffic.

I envision WiMAX being positioned initially as a wireless backhaul for data networks in towns and cities.  Take a fiber pop, put a WiMAX solution on the roof and beam huge amounts of secure and well managed bandwidth to hot spots and enterprise customers, then hop off their respective roofs to distant roof tops.  Next we'll have mobile WiMAX which is when it gets really exciting as the technology will arrive as standard on the motherboards of new laptops.

A Paradigm Shift

A Wi-Fi USA (2006)

With a Wi-Fi equipped laptop or communicator you need to first find a hotspot, then arrange to get online through the myriad of authentication and payment systems assuming it is not free and open.

A WiMAX USA (2008)

With a laptop, phone or communicator equipped with WiMAX and a single roaming agreement, you need only open up your device to get connectivity as the USA is now one giant hot spot!

Why will WiMAX win? WiMAX is not hampered by single-vendor IP licensing, WiMAX also has the highest spectral efficiency, thus allowing operators to push more packets per Dollar.