ePMP 1000 GPS or Non GPS for Access Points?

Products ePMP
1

Dear all,

I am thinking of deploying a ePMP1000 sector based Access Points consisting of 3 sectors in a single tower.

There will be approximately 6 towers in ring topology serving users within a radius of 3 KM.

This will be a high density environment where the 5Ghz is very congested. 

Can someone point out why a GPS sector unit will help in this kind of environment besides getting athe extra 50 mbps throughput?

Because considering the cost, why would a non-GPS sector not work in this case?

Thanks,

Sanay

2

Hey Me Sanay, we were recently discussing the differences between sync and non-sync, take a look at this thread.

3

Hi Sanay,

Have you considered a four sector solution at each tower.  This way you can deploy ABAB (e.g. 5800, 5775, 5800, 5775) where for four sectors you use a maximum of 45 MHz of spectrum.

When sectors on a tower are 180 degrees opposite each other, then you can use the same frequency.  When sectors are next to each other, you need 5 MHz of guard band between them.

When the sectors are opposite each other, please make sure your sector antennas have a front-to-back ratio of 30-35 dB so that they do not cause self interference between them.  For example an SM can hear the intended AP at say -60 dBm, and the AP behind it will be heard at -90 to -95 dBm because of the front-to-back ratio.  This allows you to get MCS15.  If you use sector antennas with less front-to-back ratio, then the SMs will hear the radios at a higher level (e.g. -85 dBm in this example if the front-to-back ratio is 25 dB) and cannot do MCS15 reliably.

With a three sector tower you would need to have 70 MHz of spectrum (e.g. 5775, 5800, 5825).  Neighboring sectors cannot get the 30-35 dBm of front-to-back isolation because SMs on the edge between sectors will see both sectors equally well so the APs cannot be the same frequency.

So in this case more sectors on the tower is better and will also give you better SM density.

Even three sector solutions are better than the competitors, because competitors require greater guard band for their non-synchonized radios to protect against interference.

Synchronization applies between towers so you can reuse frequencies on different towers.


Dan

4

Hi Daniel,

Yes a four sector solution may be the right choice for me.

My goal is to deploy a 4 sector ePMP 1000 NON-GPS solution in a single tower.

Then, a similar tower setup will be installed in the next 3 KM from the 1st tower and so on.

Also the areas where I am planning to deploy this kind of setup has heavy interference in the 5 Ghz space.

Do you think we can compete with this kind of setup?

Thanks,

Sanay

5

Hi Sanay,

It depends on channels you will select for your deployment.

In case you will use ABCD Frequency assigment you will need 20MHz+5MHz+20Mhz+5MHz+20MHz+5MHz+20MHz=95MHz of spectrum resource for setup of 4 non-Sync APs with 20MHz channel Bandwidth per AP deployment.

In case you will use ABAB solution you will need 45 MHz of spectrum resource.

ABAB Frequency Reuse will not work with non-Sync Radios because of Primary interference, DL and UL frames will be not synchronized and one AP will produce strong interference for opposite one.

Thank you.

6

Please take a look on topics from Knowledge Base which can help you with final decision:

http://community.cambiumnetworks.com/t5/ePMP-Synchronization/Mitigating-self-interference-in-an-ePMP-ABAB-frequency-reuse/m-p/38203#U38203

http://community.cambiumnetworks.com/t5/ePMP-Synchronization/ePMP-GPS-Synchronization/m-p/37884#U37884

Thank you.

7

Hi Fedor,

For now, due to costing, I would rather go with a 4 sector NON-GPS solution.

Later as the network grows, we could opt for the GPS solution.

As mentioned previously, my goal is to cover an area of 25 KM2 area with 100 ft towers to be able to service some 800 customers.

My initial plan is to deploy 4 towers to cover this evenly populated area.

Also there are some 7 different wireless competitors in this area which means that the 5 Ghz spectrum will be heavily populated.

We are allowed to use the frequency range of 5725 - 5825 MHz.

Can you share some thoughts on this layout?

Thanks,

Sanay

8

In that case it will work for you.

Thank you.