recommendations for dense deployment from elevated position

[Ron_Wisp]

I have few area's we are rolling out service to that I wanted to get some recommendations on. they are bowls for lack of a better word where we have access to a few towers in the hills with great vantage points over the homes in the area. the challenge is providing up to 75 mb plans in this dense area from 1 or two towers. we want to keep ratios very low 25 to 30 subs per AP tops, and will have to go lower. Currently using the Ubiquiti LTU rockets and getting great performance in other areas we have deployed. The spectrum is clean in these area's we are looking at. 

a few of the bullet questions i have - 

1.) how many horns / antennas can you get pointing the same direction out from the tower in say a 30 degree wide space that is apr 2 miles from the tower? assuming we can get the patterns tight enough for this 

2.) currently we are using 20mhz channels with great results, but the overall ap throughput is low until 4096 qam is released.  so what channel width and how many mhz of separation between horns are recommended?  i know this separation not only needs to account for the "stacking" of horns vertically covering the same 30 degree wide area, but also horizontally as we move left and right to the next 30 degree segment of coverage. 

it is probably easier than i'm making this out to be but i want this model to scale so i'm trying to prepare in advance. attached is an area in question roughly 2.5 miles by 2.5 miles. We have tower in the lower left section and the upper right.  We are on the mountain above the bowl. The below area is basically flat. 

 

Thanks, 

 Ron

[Tasos]

@Ron_Wisp Installs like this are very complicated to asses with limited info from the deployment. So many factors come into play based on noise floor, channel availability, radio platform and even CPE types.  From the looks of what you supplied you may even have towers in close proximity to others so this becomes a more in-depth design requiring a call as you already know.

To answer your specific question on the number of Horns facing in the same direction, that also depends on factors I outlined above and also depends on how much vertical mounting space you have on the tower.  With our new Asymmetrical Horns having more narrow elevation cuts and absolutely zero side-lobes you are able to stack them vertically using down-tilt to project your coverage in front of another Horn in the same azimuth.  For example you can use one Asymmetrical Horn with lots of down tilt to cover really close to the tower (0-1mile) and then another with less down tilt to cover further out (1-3miles) so those beams don't overlap but cover the same azimuth.  The numbers I used for distance is to just explain the concept and are not exact. Basically you are able to build density now vertically as people have done for years with our Symmetrical horns horizontally due to our very precise antenna beam patterns. Make sense?

To answer your second question, again that depends on many things. The amount of guard band needed between channels varies based on the radio platform and its filtering capabilities. Some are better than others, but either way our Horns help no matter what radio you choose compared to old sectors with tons of side lobes. The other things is I would not depend on 4096QAM to help with speed on existing installs as the RX levels required to achieve that modulation rate will be huge and might require a new redesign as many of your fringe customers will not be able to achieve that rate if you are currently using 256QAM. If you are using something like LTU and running at 1024QAM, you can expect your distance to be possibly cut in half...

In the end, our Horns will allow you to achieve much more density that you have ever been able to do with sectors. If you keep your distances short and AP density high you will get better results, and like any antenna type, the more space you can put between them on the tower the better your performance will be.