I'm going to save my 4.0 Firmware evaluation results for later, after I'm
finished testing.
But while working with ED Wyatt this past week, (ps. thanks Ed for the
time), It reminded of some of the cool features that had existed in the
Firmware (supported on V3 also)
One that sticks out is the way that they do Automatic Transmit Power
Control. Of course this feature is needed to prevent unnecessary
interference including at the Cell Site, by allowing CPE radios to just use
the minimum Transmit power required to get a reliable full speed link. Some
competitors use ATPC, but it only considers the desired RSSI that is
targeted, not necessarilly link quality.
Alvarion's method I felt was engenius. It uses Signal to Noise Ratio as the
criteria for adjusting the Transmit Power at CPE. This prevents the Power
level from staying lower, if the noise level rises after it is installed.
It also was very customizable, with 4 filed values that could be changes to
fine tune how you specifically wanted the ATPC to work. (for example,
considering entended modulation,), and even had an auotmatic override to
gain link association, in case a setting was made that would otherwise
prevent good link quality or association. Also in the past, when to much
noise was hit heavilly, it would reboot (in case it was an AP lockup), but
now it can be set not to reboot if preferred. It now can actually send a
trap, to notify you when the reboot would have occured, so you realize that
a link is having an interference problem. The end result was, the way they
did it, translated to a ATPC feature that would be very advantageous to be
used, apposed to a feature that would be disabled.
ATPC may not be a feature that WISPs want, who's desire is to destroy the
airways. But its an important feature for encoraging co-existinance, and for
that matter, health of your own cellsite's equipment co-location, and
commend Alvarion for their accomplishment in that feature.
This feature for other manufacturers may be a factor of which chipsets they
use and their ability to measure SNR.
The other thing that was pretty cool, was its famous abilty, to have two
seperate memory spaces for Firmware to reside.
We were able to have V3 on one image and V4 on the other Image, and with a
flick of a switch (command) jump between the firmwares, so that I could test
the performance at each of the Firmware versions. This drastically sped up
comparative testing time. But what it brings up, is that if you try a new
firmware in the field, its not a huge time consuming process to switch back,
if you need to see if the old was corrects a newly developed process. When
you have a few hundred sites, I could see that being an advantage.
Tom DeReggi
RapidDSL & Wireless, Inc
IntAirNet- Fixed Wireless Broadband
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