Patent ID: 8750245

Claim:
A method in a mobile communication device for use in initiating vertical handover of a voice or a data call between a wireless local area network (WLAN) and a wide area wireless network (WWAN), the method comprising: performing communication operations for maintaining the voice or the data call via the WLAN or the WWAN; during the voice or the data call: identifying a WLAN signal quality value of signals with the WLAN; identifying a WWAN signal quality value of signals with the WWAN; calculating a signal indicator value from both of the WLAN and WWAN signal quality values by calculating a comparative evaluation between the relative WLAN and the WWAN signal quality values; wherein calculating the signal indicator value is based on a ratio of the WLAN and the WWAN signal quality values; and wherein the initiating the vertical handover of the voice or the data call between the WLAN and the WWAN is in response to changes in the ratio over time; and initiating vertical handover of the voice or the data call between the WLAN and the WWAN based on the signal indicator value.