Patent ID: 8457070

Claim:
A method for supporting an Inter-RAT handover by an IEEE 802.16m mobile station comprising: performing, by the mobile station, a pre-registration to a target base station of an Inter-RAT using a tunneling, if a channel quality value of an Inter-RAT neighbor cell is higher than a pre-registration threshold value; and transmitting a handover request message for a handover to the target base station to a serving base station, if a channel quality value of the Inter-RAT neighbor cell is equal to or higher than a handover threshold value during a time duration in a scanning of the Inter-RAT neighbor cell and a channel quality value of the target base station is equal to or higher than that of the Inter-RAT neighbor cell, wherein the performing of the pre-registration includes: transmitting a registration request message to the target base station using the tunneling based on an L2 (second layer) protocol; and transmitting a registration complete message to the target base station using the tunneling based on an L2 protocol, upon receiving a registration accept message from the target base station, wherein the registration request message and the registration complete message are encapsulated with an Inter-RAT extended subheader and an IEEE 802.16m MAC header, wherein the Inter-RAT extended subheader includes an ID (identifier) of the serving base station and an ID of the target base station, and wherein the handover threshold value is greater than the pre-registration threshold value.