Patent ID: 8583122

Claim:
A method of transmitting a handover command to a mobile station that is using a first carrier to send or receive data from a serving base station that serves a cell, the method comprising: (a) determining that the mobile station is approaching the boundary of the cell; (b) in response to determining that the mobile station is near the boundary of the cell, transmitting to the mobile station a message that causes the mobile station to begin monitoring a second carrier; (c) after performing step (b), determining that a handover command should be transmitted to the mobile station; and (d) in response to the determination that the handover command should be transmitted to the mobile station, performing the following steps: (d1) transmitting the handover command from the serving base station to the mobile station on the first carrier; and (d2) transmitting the same handover command to the mobile station on the second carrier that is at a different frequency than the first carrier, wherein the handover command transmitted on the second carrier is transmitted from a third base station, which is different than the serving base station and a target base station.