surveying for wireless

[carl_townshend]

Hi Guys

When doing a wireless survey on a site, normally they survey for voice at -67db for the edge of the cell.

I believe typically they look for a 20% overlap, so would that be an overlap be before the edge of the cell I am guessing?

Does software like Airmagnet/Ekahau take this into account when doing a predictive survey?

Cheers

[JPavonM]

That 20% ovelap is a best practice which is very difficult to measure, and that's why all of us use the edge signal level of -67 dBm as a measure to establish when a device should start roaming and hence this is the value we set in survey tools visualizations to validate redundancy (for instance, Intermec/Honeywll barcode scanners do roam at -70 dBm, but iPhones do roam around -67/-68 dBm).

[carl_townshend]

Hi, so does the survey software automatically set the 20% overlap for you? do you tell it somewhere in the settings to do that ?

[Leo Laohoo]

I use Ekahau and takes the (second) guessing out of the equation.  

[carl_townshend]

In what way do you mean ?

[Leo Laohoo]

With Ekahau, I could set up the design for Voice- (2 APs overlapping) or RTLS (3 to 4 APs overlapping) grade with confidence. 

Otherwise, I have to "second guess" where the APs will be positioned if I have to make a design without Ekahau.  

[carl_townshend]

So are you letting ekahau place the access points for you using a predictive survey here ?

[Leo Laohoo]

Sorry, no.  That's not what I meant. 

We are manually placing the APs in Ekahau design map, however, Ekahau can evaluate if the placements will work in the either one of three scenarios we want.

For example, we want to design for RTLS, Ekahau will tell us if the design passes (or fails) RTLS because APs coverage/overlap.

[jagan.chowdam]

It's important to remember that Wi-Fi access point (AP) coverage is dynamic and influenced by various factors like transmit power, building materials, and environmental conditions. Designing with a uniform 20% overlap across the entire area might not be feasible/realistic due to these variations. 

To address this challenge, I leverage Ekahau's primary and secondary coverage functionalities. Additionally, I adjust AP power levels to closely match the expected client device range to optimize coverage efficiency.

Jagan Chowdam

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