I think that I am running into a few issues that many of us are having
and thought it would make sense to start up a discussion about what to
do when we run out of capacity.
I have two sites that are getting near to or over capacity. The one I
am most concerned about is a downtown site that has 85+ customers on a
single card. Under other circumstances, I would have sectorized this
site a long time ago, but it has visibility to four other sites (running
on 1, 4, 5 and 5) and I only have one channel that I can use reliably
at this location with an omni (channel 8).
I am using the following methods to alleviate the immediate problems:
1) Move all 1meg and high bandwidth users to 5gig AP on the same
tower. (This will pull about ten customers off of the AP)
2) Set higher rates (11meg) for customers with a signal stronger than
-55. Anyone with a high signal gets set to 11meg, and 2346 RTS setting.
These things should help, but will not alleviate the problem.
All of the customers at this AP are within 2miles of the AP and 95% of
them have excellent line of sight. 70% of the customers at this site
have a signal of -60 or better. Noise floor is between -68 to -73 (yes,
it is that noisy) on the cleanest channel. I am in H-pol, my
competitors are in V-pol, so I have to stick with H-pol. Use of 5.8Ghz
is out of the question because of backhauls on this tower and other
5.8Ghz traffic with paths crossing this tower.
I can do pretty much whatever I want on the tower. The owner is
friendly and it is a big self supporter so that is not a problem.
Long term, these are the solutions that I am considering:
1) Sectorize to three 120 degree sectors, with downtilt on them to the
point where they only have a 2mile effective radius.
PROS: Relatively cheap to implement. No change on customer
radios, just reprogramming for new IP addresses. Sectors will see less
noise individually and should penetrate trees better.
CONS: Raises the noise floor for my other APs (even with
downtilt). Somewhat unfriendly to competitors (there are at least 8
2.4ghz sectors run by competitors in the same area). Capacity will be
maxed out with this setup. There will be brief customer outages with
this scenario, especially for people who are not available for home
service calls when we do the transition.
2) Put up three 120 degree sectors of 5.2Ghz StarOS or Tranzeo APs, use
Tranzeo CPE for customers.
PROS: AP side is cheap to implement. Customer radios will be easy
to change. Little or no customer outages during switchover. Doesn't
cause more 2.4Ghz noise. Much higher capacity access points.
CONS: $250 CPE. Less tree penetration (could be overcome by
leaving up the old omni for customers with tree issues).
3) Put up three sectors of Tranzeo 5830 APs running in 5.2Ghz, modded
to work with 120 degree sectors
PROS: $149 CPE. Customer radios will be easy to change. Little or
no customer outages during switchover. Doesn't cause more 2.4Ghz
noise. Higher capacity access points (but not as high as #2). Robust
MAC designed for outdoor use.
CONS: APs are expensive to purchase and require warranty voiding
modification. CPEs require new training for techs. APs have a
different interface to learn and are not compatible with our preferred
4) Motorola 5.2Ghz Canopy cluster
PROS: $150 CPE. Little or no customer outages during switchover.
Doesn't cause more 2.4Ghz noise. Robust MAC designed for outdoor use
CONS: Most expensive system to implement. CPEs have limited
bandwidth (using Lite). CPEs require new training for techs. APs have
a different interface to learn and are not compatible with our preferred
system (StarOS). Will use up pretty much all of the 5.2Ghz spectrum.
May cause problems for schools in the area using 5.2Ghz Canopy. Oh
yeah....Motorola sucks - they are tacky and I hate them.
I am leaning toward option #2. If I could get Tranzeo 5ghz CPE units
for $175, it would be a no-brainer. Same management platform on both AP
and CPE sides. No extra training for installers.
Option 3 would be doable as well - we have some experience with Trango
and it has been pretty good so I don't think it would be too much to ask
of our techs to learn it. Only concern there would be finding myself on
the bleeding edge with a new, relatively unproven CPE unit.
I look forward to comments from any and all about what to do in this
situation. I hope that many of us continue to grow to the point where
we get to address these things on a regular basis. :^)
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