Technical Tip: Resolving Poor WiFi Connectivity for iOS Devices

Description

This article describes a solution to resolve poor WiFi connectivity issues for iOS devices. The user is experiencing bad WiFi with their specific devices that are using iOS, while devices running on Android OS do not have any issues.

Scope

FortiGate, FortiAP.

Solution

To resolve the poor WiFi connectivity issue for iOS devices, follow these steps:

• Optimize TX Power (Initial Step)

  • Navigate to the FortiAP Profile on the FortiGate.

  • Adjust the transmit power for both 2.4 GHz and 5 GHz radios.

  • Recommended range: 10–17 dBm (depending on environment).

  • Apply the changes to a small group of APs for testing.

• Enable 802.11k and 802.11v (Roaming assistance).

Go to the SSID (VAP) configuration:

config wireless-controller vap

edit <ssid_name>

set 80211k enable

set 80211v enable

next

end

These features help clients discover nearby APs and improve roaming decisions.

• Validate roaming behavior:

  • Test with iOS devices moving between AP coverage areas.

  • Confirm whether devices roam more smoothly without disconnecting.

• Collect Station Logs (If the issue persists):

Capture logs during a roaming event to analyze client behavior.
Refer to: Technical Tip: Collecting station log for a wireless client when there is a VDOM Configured

• Verify firmware versions:

  • Check the current FortiOS and FortiAP firmware versions.

  • Upgrade to the latest recommended release if not already done.

  • Follow proper upgrade procedures and verify compatibility.

• Test in a controlled environment:

  • Perform changes on a limited AP group or test SSID/VLAN.

  • Validate performance before applying changes network-wide.

• (Optional) Consider RX-SOP (Advanced tuning):

If roaming issues persist, enable RX-SOP to influence earlier roaming:

config wireless-controller vap

edit <ssid_name>

set radio-sensitivity enable

set radio-5g-threshold "-76"

set radio-2g-threshold "-79"

next

end

Note: This should be tested carefully, as aggressive thresholds may cause temporary disconnections.