Cellphone WiFi Connectivity Issues

[mackdav]

I have a FortiGate-90D controlling four FAP-320 access points.  All are running 5.2.2 firmware.

I have a couple of noisy clients who have android or blackberry phones which have trouble connecting to the WiFi network.  Laptop and other phones (some of which are android) do not generally have issues.

Most of the time the phone will connect, however occasionally the phone will repeatedly try to connect to the network and then fail with "Avoided poor network connection".  The network is a WPA2-Enterprise network with an AD server providing authentication via Radius.

How do I go about troubleshooting this problem?

[mackdav]

Note -- this turned out to be a combination of my other wifi problem and android handsets running ancient firmwares.