Hack 5 802.16: Long Distance Wireless Infrastructure
The long awaited Municipal Area Network
protocol is on the way, but isn't here just
yet.
Approved on December 6, 2001, 802.16
promises to be the answer to all of the shortcomings of long distance
applications that people have encountered using 802.11 protocols. It
should be pointed out that the 802.11 family was never intended to
provide long distance, metropolitan-area
coverage (although I'll show you some examples of
people doing exactly that). The 802.16 specification is specifically
designed for providing wireless infrastructure that will cover entire
cities, with typical ranges measured in kilometers. It will use
frequencies from 10 to 66 GHz to provide commercial quality services
to stationary locations (i.e., buildings). In January 2003, a new
extension (802.16a) was ratified, which will operate in the 2 to 11
GHz range. This should help significantly with line-of-sight
requirements of the extremely short waves of 10 to 66 GHz.
Realistically, actual equipment that implements 802.16 is just now
coming to market, and will likely be priced well above the
consumer-grade equipment of the 802.11 family.
Pros
802.16 is designed for long-range networking, likely providing ranges
of 20 to 30 kilometers.Very high speed for fixed wireless,
probably about 70 Mbps.
Cons
Shorter wavelengths of 10 to 66 GHz are more susceptible to signal
fade due to
environmental conditions (such as
rain).Many bands used by 802.16 and 802.16a are licensed spectrum.It's just not available yet.
Recommendation
It will be interesting to see the 802.16 MAN story as it evolves, but
it's too early to tell how this technology will
fare. Fujitsu is currently developing an 802.16a chipset that it
expects to have ready sometime in 2004, and is currently targeting a
price tag of about $300. 802.16 will certainly be a welcome
technology for long distance point-to-multipoint applications,
which are difficult to implement effectively using 802.11. But
unfortunately, the hardware isn't available to play
with yet. |
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