Worldwide
Interoperability for Microwave access is a wireless communication standard
operating at a frequency of a few Gigahertzes (mainly at 2.5 , 3.5 and 5.8),
which could initially provide 30 to 40 megabits per second and increased to 1 Gigabit with the
2011 update. It can operate at a radius of several kilometers (in principle up
to ~50 kilometers with a bitrate of a couple of megabits), covering very large
areas. The first final version of WiMax was IEEE 802.16-2004 in 2004 and the
most recent is IEEE 802.16m in 2011. WiMax has achieved some considerable
penetration in developing countries mainly in Southeastern Asia, but has until
today failed to compete GSM/CDMA in the Western World. Even though no one can
be sure about the future, it seems to be very difficult for WiMax to gain a big
market share in the West. Nevertheless, the developing countries around the
world sum up to a very big percentage of the global population and can create a
critical subscribers’ mass for WiMax. Until now, it can probably be considered
to be a failure in general (maybe because of the great initial expectations
created), but things can change in the future [7].
The standardization of
WiMax involves three different entities: IEEE with the 802-16 Working Group,
the WiMax Forum and the International Telecommunications Union. IEEE 802.16 WG
develops the basic technical specifications, closer to the physical layer. WiMax
Forum adds some extra features, closer to the application layer and issues
compatibility and interoperability certificates for vendors. ITU gives a more
formal and official recognition, mainly to the spectrum allocated and used for
WiMax worldwide. WiMax standardization allows vendors to produce equipment
compatible with each other’s in big quantities, that drop the manufacturing
cost. Furthermore, as good practices are adopted in the standard, the hardware
and software used achieve the best possible result with the minimum price
(value for money), thus decreasing even more the costs [1].
What has been learnt
from the WiMax standardization process is that developing a new standard should
not be blind to new features and characteristics that can dramatically change
the way forward, with the example of the spectrum, as IEEE was initially
researching the 10-66 GHz spectral region, which would not allow a very large
coverage area from a base station and would cause many problems in both
amplifying the signal and processing it digitally, compared to the region of
2-11 GHz that was later researched. The importance of the certification from
the WiMax Forum is also significant, as interoperability is a key feature for
the widespread penetration of any technology. Finally, the collaboration with
other international organizations (like ITU) can rise the esteem of a standard
and facilitate new deployments and development.
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