WLAN-to-WLAN handover decisions and WLAN-to-WWAN handover decisions for a portable user device conducting a VoIMS call typically are based on a scan list that lists identified WLAN APs and their detected signal quality characteristics. The conventional approach of periodically updating the scan list can result in an out-of-date listing of available WLAN APs and their signal quality characteristics, which can result in sub-optimal handover decisions and thus a sub-optimal voice call experience. The handover decision process is improved by using other triggers to initiate an updated WLAN AP scan, including using activation of a dialer GUI or other indication that a voice call is about to be placed, degradation of a WWAN connection supporting a current voice call, and the like. Through increases in the frequency of WLAN AP scans balanced against the power consumed by such scans, a more accurate and timelier WLAN AP scan list is made available for handover decisions, and thereby supporting a higher-quality voice call experience.

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This work is licensed under a Creative Commons Attribution 4.0 License.