Patent ID: 8917659

Claim:
A method of transmitting a warning message in a multiple carrier system performed by a network, the method comprising: aggregating multiple downlink component carriers including a first downlink component carrier (CC) and a second downlink component carrier (CC); transmitting, to a user equipment (UE), carrier information on the first downlink component carrier, wherein the first downlink CC is a warning CC which is used to transmit a warning message; transmitting, to the UE, a notification on the second downlink component carrier (CC), the notification informing the UE of an upcoming transmission of the warning message, wherein the second downlink CC is a non-warning CC that is used for transmitting data other than the warning message, including the notification, wherein the notification includes warning CC information which indicates a specific warning CC or a list of warning CCs, wherein if the warning CC information includes the specific warning CC, the warning message will be transmitted on the specific warning CC, and if the warning CC information includes the list of warning CCs, the warning message will be transmitted on one or more downlink CCs included in the list of warning CCs; and when the first downlink CC is the specific warning CC or one of the one or more downlink CCs included in the list of warning CCs, transmitting, to the UE, the warning message on the first downlink component carrier, wherein the first downlink component carrier is different from the second downlink component carrier, wherein the notification is transmitted via a physical downlink control channel (PDCCH) with a public warning system specific radio network temporary identifier (PWS specific RNTI), wherein the first downlink component carrier is not used to transmit the notification, wherein the second downlink component carrier is not used to transmit the warning message, wherein the UE stores a message identity (ID) and a serial number (SN) of the warning message, wherein the UE discards the stored message ID and the stored SN if the UE enters into a cell that is different from a current cell, and wherein the UE does not discard the stored message ID and the stored SN if the UE moves in between aggregated downlink carriers.