choosing power

[wyfy-2015]

Hi,

When building  a high density deplyment  , what is the right power to choose for 2.4 and 5 ghz

Some site survey tool says  for 2,4 ghz choose 3dBm

and for 5 ghz choose 16dBm

What is the best practice  from cisco 

[Rasika Nayanajith]

Most important thing is how you do channel re-use in these sort of environment. It is best if you could avoid any channel reuse (ie 3 CH for 2.4GHz and max 24 CH in 5GHz with 20Mz). If you have to reuse channels, then you have to reduce RF foot print of each AP by choosing right antenna types.(directional)

Therefore power level should be based on how you use these frequencies. If you re-use same channel for more than 1 AP then you have to control power in order to reduce CCI (Co Channel Interference)

Typically 8 -14dBm for 5GHz and 0-7dBm for 2.4GHz common

Again end of the day depend on your setup you have to decide power level of APs .

HTH

Rasika

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[wyfy-2015]

Hi

"Again end of the day depend on your setup you have to decide power level of APs "

Can you give one example  setup 

Thanks

[Rasika Nayanajith]

If you have already deployed this, then share how your design looks like (ie how many AP & what channels are they in). So we can give some advice.

Even if it is propose design, share that info, so we can give some suggestions.

What site survey tools did you use ? If you have Ekahau product, you can model these & see how those power changes impacting

HTH

Rasika

[wyfy-2015]

Hi,

Thank you rasika for your help . 

We have around  250 AP's , channels are  Channels are UNII-1 and UNII-2 UNII-3 

But i could not see DCA assigned  UNII- 3 channels ? .

" What site survey tools did you use ? If you have Ekahau product, you can model these & see how those power changes impacting " 

If i model  in ekahau by adjusting power  , as long as  i am using auto tpc and  dca 

how do i incorporate in my deployment ?

In 240 feet i have 4 AP'S deployed , Almost every 60 feet one AP. 

Thanks 

[wyfy-2015]

Hi,

Let's say Supported Country Maximum Power is 20 dBm , Tpc value max is 11 dBm
and Channel 36 Max is 23 dBm
So at the end what will be the power value

Thanks

[Rasika Nayanajith]

If you leave RRM to choose power level, then it will capped to 11dBm

HTH

Rasika

[wyfy-2015]

Hi,

It means  EIRP is  11 dBm

Thanks

[wyfy-2015]

Hi Rasika,

By reducing the tpc max and min are we reducing the cell size

Thanks

[Rasika Nayanajith]

Yes that's true. on the other hand having a large cell won't help at all. Everything determine by averaged client capability (typically 10-14dBm).

If you have AP transmit high power, client will hear it. But when client communicate back from a cell edge, AP won't hear it. 

HTH

Rasika

[wyfy-2015]

Hi Rasika

Reducing the cell size will reduce the coverage also ?

Thanks

[wyfy-2015]

Hi,

The information provided is enough ?

Thanks

[Rasika Nayanajith]

In my network I have set up TPC min/max for 5GHz as 8dBm/17dBm.

In 2.4GHz band, i would reduce this further 3dBm - 11dBm as singal goes long when frequency is low.

HTH

Rasika

[wyfy-2015]

Hi,

It would be great if you  provide  how did you reach this  value ? .

And moreover that in  my proposed design there is only one value for  5 ghz and 2.4 Ghz (No maximum or  minimum specified ) 

Thanks

[Rasika Nayanajith]

Hi,

These are the setting I have done on WLC (under Wireless -> 802.11a/n/ac ->RRM -> TPC)

Then leave RRM to decide power level dynamically within this range.

In survey tool (Ekahau) use 7 or 10dBm as 5GHz AP radio power & work it out number of APs required (also considering bandwidth/capacity requirement)

HTH

Rasika