Patent ID: 8054802

Claim:
A method for hand-off trigger at access technology borders, comprising: acquiring, by a mobile station in communication with a first carrier having a first technology type, synchronization with a second carrier having a second technology type if the mobile station enters a border area, the border area including at least one sector covered by at least two carriers having different Radio Access Technologies (RATs) including the first technology type and the second technology type; triggering a hand-off of the mobile station to the second carrier if a channel condition of the second carrier is above a first threshold value, the mobile station fails to receive a second message in response to a first message sent to the first carrier in an expiring time interval, and a number of the first messages have already been sent to the first carrier; and triggering the hand-off of the mobile station to the second carrier if the channel condition of the second carrier is above the first threshold value, the mobile station receives the second message in response to the first message sent to the first carrier within the expiring time interval, and the message indicates that a distance from the mobile station to the current base station of the first carrier is above the distance threshold.