Πέμπτη, 11 Ιουλίου 2013

Conclusions and Overview of WiMax Standardization

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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