Maximum transmit power of mobile phones

[gnf52183]

Let's suppose I have an access point with directional antenna (C-ANT9103=) which is capable of covering 40meter area in direction of antenna. User is standing 20meters in front of the antenna. Will user be able to talk to access point without any issues or is there a transmit power limitation due to which user will have a good signal but will be unable to transmit. Let's suppose there are no obstacles in a way and client is connecting to wifi with RF gun.

[Dustin Anderson]

you would have to look up the specifics of the transmit power of the device, but from what I have seen you can plan them ~25mW. 

Our warehouse is planned with APs ~120ft(~37meters) apart. This sets our roam about 60 ft, but can easily stay connected past that to give the roaming overlap area. We have our APs set at 25mW with no connection issues so I would expect you to see similar.

Now, all this is always a guess, you would have to get a test AP and antenna and verify how far you can maintain a connection. Because in the end who knows on a device. An example is we have these Dell rough tablets and people were complaining, we found they picked up 10dB less on 5GHz than other devices.

[Prince.O]

Hello,

There is no easy to answer this as the best way to validate this will be via wireless design with testing to observe the behavior as every client device varies. So , I would recommend a proper wireless design(whether predictive or APoS ) factoring in the least capable device for your design whether it be the RF gun in this case to confirm the expected behavior.

- If wireless is already deployed, then you can perform a validation survey to get a visualization of your RF environment

[Leo Laohoo]

I do not see any problems with that distance.

[JPavonM]

To prevent issues with distance between AP and devices you need to avoid power impairment. If AP Tx Power exceed that on the client device, then you would have a problem. Antennas only add gain to the signal in the both directions, but if the maximum Tx power from client (which you cannot control in smart devices) is from a value that after adding antenna's gain it doesn't match that from adding Tx Power plus gain on the AP side, then it is likely that the client device won't be heard  by the AP.

If you don't know the maximum transmission power from the device, most of the times you can check that from the FCC site using the FCCID code on the device's label.

For example check this from a Samsung S22 device:
https://fcc.report/FCC-ID/A3LSMS901U/5567252