To the thread:
LMDS is starting to get some respect as a technology.
The January 1998 Analysis and Forecast Issue of IEEE
Spectrum (the main general interest magazine of the
IEEE) contains a section on LMDS in its communications
part. It includes a quote from George Hendry, VP at
Stanford Telecommunications in Sunnyvale, CA, indicating
that LMDS is well suited in urban areas like Sunnyvale,
which average 12,000 homes per square kilometer. He
estimates that the US market for LMDS will be about
4 to 5 million customers.
His comment about Sunnyvale probably alludes to the
following operating constraints affecting LMDS:
a) Two years ago, a report was written by Bellcore
engineers who tested CVUs's system in Brooklyn.
They found that LMDS signals are significantly
affected by skyscrapers and obstructions. They found
that for antennas located 4m above the ground there
was only about a 70% customer coverage probability
within a 1km distance from the transmitter. On the
other hand, the probability increased significantly
if the antenna was 10m above the ground.
b) Other technical papers I read shows that rain
attenuation is not a significant problem, but foliage
is a serious difficulty. A study was made of millimeter
wave propagation in San Jose, CA, (which tends to have
only relatively immature trees), and at a location
in Colorado with significant foliage. Miilimeter waves
suffer from severe attenuation and scattering due to
foliage.
Thus, the ideal operating conditions for LMDS are
low skyline and low vegetation areas, such as one
finds in the San Francisco Bay area (or Los Angeles).
I would expect therefore that licenses in CA urban
areas will go for the highest price, by far.
Incidentaly, the experimental findings concerning
LMDS coverage do not mean that LMDS service cannot
be offered in more challenging areas. The infrastructure
costs will be more expensive, since more closely
spaced cells will be required, as well as more repeaters.
For example, I believe that the HP/Stanford Telecom
system relies on overlapping cells to increase the
service coverage. It is quite important that coverage
should be high, since the service reputation suffers
tremendously from disgruntled customers. For example,
one of the early posters on this thread who lived
in Brooklyn was extremely negative about CVUS when
he discovered he could not be serviced. Other customers
who post on Yahoo seem extremely satisfied. |
