We have been indoors too long. Let us now go outside and see if any interesting networking is going on there. It turns out that quite a bit is going on there, and some of it has to do with the so-called last mile. With the deregulation of the telephone system in many countries,
competitors to the entrenched telephone company are now often allowed to offer local voice and high-speed Internet service.
There is certainly plenty of demand. The problem is that
running fiber, coax, or even category 5 twisted pair to millions of homes and businesses is
prohibitively expensive. What is a competitor to do?
The answer is broadband wireless. Erecting a big antenna on a hill just outside of town and
installing antennas directed at it on customers' roofs is much easier and cheaper than digging
trenches and stringing cables. Thus, competing telecommunication companies have a great
interest in providing a multimegabit wireless communication service for voice, Internet, movies
on demand, etc. As we saw in Fig. 2-30, LMDS was invented for this purpose. However, until
recently, every carrier devised its own system. This lack of standards meant that hardware and
software could not be mass produced, which kept prices high and acceptance low.
Many people in the industry realized that having a broadband wireless standard was the key
element missing, so IEEE was asked to form a committee composed of people from key
companies and academia to draw up the standard. The next number available in the 802
numbering space was 802.16, so the standard got this number. Work was started in July
1999, and the final standard was approved in April 2002. Officially the standard is called ''Air
Interface for Fixed Broadband Wireless Access Systems.'' However, some people prefer to call
it a wireless MAN (Metropolitan Area Network) or a wireless local loop. We regard all these terms as interchangeable.
Like some of the other 802 standards, 802.16 was heavily influenced by the OSI model,
including the (sub)layers, terminology, service primitives, and more. Unfortunately, also like
OSI, it is fairly complicated. In the following sections we will give a brief description of some of the highlights of 802.16, but this treatment is far from complete and leaves out many details. For additional information about broadband wireless in general, see (Bolcskei et al., 2001; and Webb, 2001). For information about 802.16 in particular, see (Eklund et al., 2002).
Broadband Wireless
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