Abstract:
A method of handling notification message transmission for a network of a wireless warning communication system includes when content of a notification message comprising a message identity is changed, modifying the message identity, wherein the message identity is included in a system information block, hereinafter called SIB, and indicates which notification message a notification message content in the SIB belongs to; and sending the SIB and a paging message comprising at least one of a flag and an element, wherein the flag is used to notify a user equipment of a change of the SIB, and the element is a notification indication used to notify the user equipment to acquire the SIB when the element is found in the received paging message.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of U.S. application Ser. No. 12/264,270 filed on Nov. 4, 2008, which further claims the benefit of U.S. Provisional Application No. 61/098,793, filed on Sep. 21, 2008 and entitled “METHOD AND RELATED COMMUNICATION DEVICE FOR ETWS TRANSMISSION AND RECEPTION IN A WIRELESS COMMUNICATION SYSTEM”. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a method and device utilized in a wireless communication system, and more particularly, to a method and communication device for notification message transmission and reception of a natural disaster warning of the wireless communication system. 
     2. Description of the Prior Art 
     Earthquake and Tsunami Warning System (ETWS), set forth by the 3rd Generation Partnership Project (3GPP), introduces a means to deliver Warning Notification simultaneously to many mobile users who should evacuate from approaching Earthquake or Tsunami. The ETWS consists of a PLMN (Public Land Mobile Network) that is capable to deliver Warning Notification and user equipments (UEs) that are capable to receive Warning Notification. The PLMN of the ETWS can be a GERAN (GSM/EDEG radio access network) of a 2G/2.5G GSM system, a UTRAN (UMTS radio access network) of a 3G UMTS system, or a EUTRAN (evolved-UTAN) of a long term evolution (LTE) system. Warning Notification Providers, which are usually run by local governments, produce Warning Notification to PLMN operator when an earthquake or tsunami event occurs. 
     Warning Notification is classified into two types depending on the purpose and urgency of the notification. The first type of Notification is called Primary Notification that delivers the most important information of the threat that is approaching to users (e.g. the imminent occurrence of Earthquake or Tsunami) and shall be delivered to the users as soon as possible. For example, the Primary Notification can notify the UE of the disaster type. The second type of Notification is called Secondary Notification that delivers additional information, such as instructions on what to do or where to get help. 
     The Warning Notification Provider publishes a Primary Notification to PLMN and specifies the Notification Area where the Warning Notification is expected to be distributed when occurrence of a natural disaster is detected. Single or multiple Secondary Notifications are published following the Primary Notification. Finally, the Warning Notification Provider may request dissemination of notification to the PLMN to stop. 
     According to the related specifications so far, a primary notification message corresponding to the Primary Notification and a secondary notification message corresponding to the Secondary Notification are both provided by system information that is seen as broadcast information and transmitted on a BCCH (Broadcast Control Channel). The primary notification message is contained in a SIB10 (System Information Block Type 10), whereas the secondary notification message is contained in a SIB11 or multiple SIB11s. 
     The primary notification can occur at any point in time. A paging message is used for informing the UEs about presence of the primary notification. If the UE receives the paging message including “etws-PrimaryNotificationIndication”, the UE knows that the ETWS primary notification is present. 
     “etws-PrimaryNotificationIndication” is a value represented by one bit and included in the paging message to indicate “ETWS primary notification present”. When receiving this bit of the paging message, the UE immediately reads a SIB1 to find scheduling information for the SIB10 and read the SIB10 including the primary notification message. 
     The secondary notification message is allowed to be segmented, and the segments are transmitted via multiple SIB11s. Transmission cycles through the different segments belonging to a single secondary notification message at subsequent occasions for this SIB. 
     The PLMN possibly publishes several secondary notification messages with different content. Each of the secondary notification messages can be transmitted segment by segment via the SIB11. However, the abovementioned specifications do not specify any actions of the UE about how to know which secondary notification message each segment belongs to. When the UE does not identify which secondary notification message a received segment belongs to, the segments corresponding to different secondary notification messages may be combined together. In this situation, a decoding result of the complete secondary notification message turns out unreadable text content. Consequently, the user is not able to follow indication of the secondary notification message. 
     According to the abovementioned specifications, the UE receives the primary notification message after the paging message including the “etws-PrimaryNotificationIndication” is received. Then the UE receives the secondary notification message after a primary notification message is received. However, the secondary notification messages may be arrived at the UE before the primary notification message due to system information scheduling. In this situation, the UE is unable to receive the secondary notification message since the primary notification message has not been received. To achieve an emergent disaster notification system, the primary and secondary notification messages should be received as soon as possible. 
     SUMMARY OF THE INVENTION 
     The present invention therefore provides a method and related communication device for a notification message reception and transmission corresponding to message content change and message targets for a natural disaster warning system of a wireless communication system that can avoid incorrect decoded message content and can enhance notification efficiency. 
     According to an embodiment of the present invention, a method of handling notification message transmission for a network of a wireless warning communication system is disclosed. The method includes when content of a notification message comprising a message identity is changed, modifying the message identity, wherein the message identity is included in a system information block, hereinafter called SIB, and indicates which notification message a notification message content in the SIB belongs to; and sending the SIB and a paging message comprising at least one of a flag and an element, wherein the flag is used to notify a user equipment of a change of the SIB, and the element is a notification indication used to notify the user equipment to acquire the SIB when the element is found in the received paging message. 
     According to an embodiment of the present invention, a method of handling notification message reception for a user equipment of a wireless warning communication system, is disclosed. The method includes receiving a paging message comprising at least one of a flag and an element, wherein the flag is used to notify the user equipment of a change of a system information block (SIB) comprising content of a notification message, and the element is a notification indication; and acquiring the SIB and discarding any buffered notification message content in a buffer of the user equipment, when the element is found in the received paging message. 
     According to an embodiment of the present invention, a method of handling notification message transmission for a network of a wireless warning communication system is disclosed. The method includes including a message identity in each of a plurality of system information blocks, hereinafter called SIBs, wherein each SIB comprises a segment of content of a same notification message, wherein the message identity is used to indicate which notification message each SIB belongs to; and sending the SIBs and a paging message comprising at least one of a flag and an element, wherein the flag is used to notify a user equipment of a change in the SIBs, and the element is a notification indication used to notify the user equipment to acquire the SIBs when the element is found in the received paging message. 
     According to an embodiment of the present invention, a method of handling notification message reception for a user equipment of a wireless warning communication system is disclosed. The method includes receiving a paging message comprising at least one of a flag and an element, wherein the flag is used to notify the user equipment of a change of a system information block (SIB) comprising content of a notification message and a message identity, and the element is a notification indication; receiving the SIB when the element is found in the received paging message; and generating the notification message with the received SIB, wherein the message identity is used to notify the user equipment which notification message the SIB belongs to. 
     These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of a wireless communication system. 
         FIG. 2  is a schematic diagram of a communication device according to embodiments of the present invention. 
         FIGS. 3-12  are flowcharts of processes according to embodiments of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Please refer to  FIG. 1 , which illustrates a schematic diagram of a wireless communication system  10  according to an embodiment of the present invention. The wireless communication system  10  is an Earthquake and Tsunami Warning System based on a 2.5G/3G mobile telecommunication system, an LTE (long-term evolution) system or other mobile communication systems, and is briefly composed of a network and a plurality of UEs. In  FIG. 1 , the network and the UEs are simply utilized for illustrating the structure of the wireless communication system  10 . Practically, the network may be a public land mobile network (PLMN), such as a GERAN (GSM/EDEG radio access network) of a 2G/2.5G GSM system, a UTRAN (UMTS radio access network) of a 3G UMTS system, or a EUTRAN (evolved-UTAN) of the LTE system, comprising a plurality of base stations (i.e. BTSs, Node-Bs, or eNBs), network controllers (i.e. Base Station Controllers or Radio Network Controllers) and so on according to actual demands. The UEs can be devices such as mobile phones, computer systems, etc. Besides, the network and the UE can be seen as a transmitter or receiver according to transmission direction, e.g., for uplink, the UE is the transmitter and the network is the receiver, and for downlink, the network is the transmitter and the UE is the receiver. 
     Please refer to  FIG. 2 , which illustrates a schematic diagram of a communication device  20  according to embodiments of the present invention. The communication device  20  is utilized for realizing the network or the UEs shown in  FIG. 1  and includes a processor  200 , a computer readable recording medium  210 , a communication interfacing unit  220  and a control unit  230 . The computer readable recording medium  210  is any data storage device that stores storage data  212 , including program code  214  of a process and corresponding parameters (i.e. a timer or a flag if necessary). The storage data  212  and the process thereof are thereafter read and processed by the processor  200  to generate processing results. Examples of the computer readable recording medium include read-only memory (ROM), random-access memory (RAM), CD-ROMs, magnetic tapes, floppy disks, optical data storage devices, and carrier waves (such as data transmission through the Internet). The control unit  230  controls the communication interfacing unit  220  and related operations and states of the communication device  20  according to the processing results of the process  200 . The communication interfacing unit  220  is responsible for exchanging wireless signals with a peer communication device. 
     When a natural disaster (i.e. an earthquake or a tsunami) occurs, the network of the wireless communication system  10  receives one or more Primary Notifications and one or more following Secondary Notifications published by a Warning Notification Provider and thereby sends Primary Notification messages and the Secondary Notification messages to the UE via system information block types 10 and 11 (SIB 10 and SIB11). Through a BCCH (Broadcast Control Channel), the UE reads an SIB1 for scheduling information of the primary or secondary notification message. In addition, the primary or secondary notification message can be transmitted with multiple segments. 
     When the warning notification provider attempts to publish multiple primary and secondary notification messages with different content, the following processes  30  and  50  are provided for the network to modify content of transmission information corresponding to the notification message transmission when content of the notification message is changed. Accordingly, the following processes  40  and  60  are provided for the UE to clear data corresponding to the notification message in a buffer according to content of the received transmission information. 
     Please refer to  FIG. 3 , which illustrates a flowchart of a process  30  according to an embodiment of the present invention. The process  30  is utilized for handling a content change of a notification message corresponding to ETWS for a network of a wireless communication system and can be compiled into the program code  214  of the process in the storage data  212 . The process  30  includes the following steps: 
     Step  300 : Start. 
     Step  302 : Include a value tag for indicating the content change of the notification message in a SIB including scheduling information of the notification message. 
     Step  304 : Change the value tag included in the SIB when content of the notification message is changed. 
     Step  306 : When the content of the notification message is changed, add a flag in a paging message for notifying an ETWS capable UE of a change of the SIB. 
     Step  308 : Send the SIB and the paging message to all UEs in ETWS notification coverage. 
     Step  310 : End. 
     According to the process  30 , a value tag for indicating the content change of the notification message is included in the SIB including the scheduling information. When the content of the notification message is changed, the network changes a value tag to notify the UE of the content change. Preferably, the network increments the value tag. Meanwhile, the network further adds a flag in a paging message for notifying the UE of the SIB change. Finally, the network sends the SIB and the paging message to the UEs by means of broadcasting and paging respectively. 
     The notification message is the primary or the secondary notification message. In this situation, the SIB including the scheduling information is the SIB1. When the SIB1 is employed in the process  30 , the network can use a joint or separate value tags for indicating the content change of the primary and secondary notification messages. 
     The value tag is preferably dedicated for SIB11, SIB 10 or both of the SIB11 and SIB 10. When the value tag is dedicated for either SIB11 or SIB 10, this means that separates value tags are used for the primary or the secondary notification messages respectively. When the value tag is dedicated for both of the SIB11 and SIB 10, this means that a joint value tag is used for the primary or the secondary notification messages. 
     Alternatively, the value tag is used for notifying the UEs of changes of any SIBs other than SIB1, such as SIB5, SIB6, SIB10 or SIB11. In other words, the value tag is not the value tag for indicating changes of any SIBs. 
     To cooperate with the network adopting the process  30 , the following processes are provided for the UE to be aware of the content change. Please refer to  FIG. 4 , which illustrates a flowchart of a process  40  according to an embodiment of the present invention. The process  40  is utilized for handling a content change of a notification message corresponding to ETWS for an ETWS capable UE of a wireless communication system and can be compiled into the program code  214  of the process in the storage data  212 . The ETWS capable UE keeps receiving the notification message and stores related data into a buffer. The process  40  includes the following steps: 
     Step  400 : Start. 
     Step  402 : Receive a paging message including an element indicating existence of the notification message. 
     Step  404 : Receive an SIB comprising a value tag for indicating content change of the notification message when the paging message is received. 
     Step  406 : Read the value tag from the SIB. 
     Step  408 : Clear all data corresponding to the notification message in the buffer of the UE when the read value tag is different from the previous value tag. 
     Step  410 : End. 
     According to the process  40 , the ETWS capable UE receives the paging message including the element and thereby turns to receive the SIB. The UE is aware of the SIB change by receiving the value tag. After the SIB is received, the ETWS capable UE reads the value tag from the SIB and clears all data corresponding to the notification message in the buffer when the read value tag is different from the previously read value tag. 
     Preferably, the notification message is the primary or the secondary notification message. The element is an “etws-PrimaryNotificationIndication” element. The SIB is an SIB 10 including the primary notification message or an SIB11 including the secondary notification message. Alternatively, the SIB is the SIB1 including the scheduling information. When the network uses a joint value tag, the UE clears all data corresponding to both of the primary and secondary notification messages in the buffer. When the network uses separate value tags, the UE clears all data corresponding to the primary or the secondary notification message in the buffer depended on the read value tag. When a dedicated value tag is used, the ETWS capable UEs turn to receive the SIB11 or SIB10 because of the SIB change, whereas ETWS non capable UEs ignore the SIB change. 
     As can been from the above, for ETWS, the embodiments of the present invention provides (1) when the content in the secondary notification message is changed, the value tag in SIB1 is changed, (2) when the content in the primary notification message is changed, the value tag in SIB1 is changed, and (3) a separate value tag can be used defined for SIB10, for SIB11, or for SIB10 and SIB11. 
     Please note that those skilled in the art can use other parameters to realize the processes  30  and  40 . For example, a message ID included in the SIB11 can be used. 
     When the SIB1 includes no value tag for SIB10 or SIB11, the following processes are provided for awareness of the content change of the notification message. Please refer to  FIGS. 5 and 6 , which illustrate flowcharts of processes  50  and  60  according to an embodiment of the present invention. The processes  50  and  60  are utilized for handling a content change of a notification message corresponding to ETWS for a network and an ETWS capable UE of a wireless communication system, respectively. The ETWS capable UE stores related data related to the notification message in a buffer. The processes  50  and  60  can be compiled into the program code  214  of the process in the storage data  212 . The process  50  includes the following steps: 
     Step  500 : Start. 
     Step  502 : Send a page message including an element to the UE when content of the notification message is changed. 
     Step  504 : End. 
     According to the process  50 , the network sends a page message including an element to the UE when the content of the notification message is changed. 
     In addition, the process  60  includes the following steps: 
     Step  600 : Start. 
     Step  602 : Receive a page message including an element from the network. 
     Step  604 : Clear all data corresponding to the notification message in the buffer when the element is found in the received page message. 
     Step  606 : End. 
     According to the process  60 , when the element is found in the received page message, the UE is aware of the content change and then clears all the data related to the old content of the notification message in the buffer. After buffer clearing, the UE turns to receive the notification message with new content. 
     When the notification message is secondary notification message, the element is a secondary notification change indicator or “etws-PrimaryNotificationIndication” for notifying the UE of the content change. When the notification message is primary notification message, the element is “etws-PrimaryNotificationIndication”. 
     As can be seen from the processes  50  and  60 , the embodiment of the present invention provides ETWS with (1) a paging message is sent to notify a UE of a content change of the primary notification message when no value tag in the SIB1 is used for changes of the SIB 10, and (2) a paging message is sent to notify a UE of a content change of the secondary notification message when no value tag in the SIB1 is used for changes of the SIB 11. 
     Please refer to  FIGS. 7 and 8 , which illustrate flowcharts of processes  70  and  80  according to an embodiment of the present invention. The processes  70  and  80  are utilized for handling a content change of a notification message corresponding to ETWS for a network and an ETWS capable UE of a wireless communication system, respectively. The processes  70  and  80  can be compiled into the program code  214  of the process in the storage data  212 . The process  70  includes the following steps: 
     Step  700 : Start. 
     Step  702 : Include a message identity (ID) in a SIB including content of the notification message. 
     Step  704 : End. 
     According to the process  70 , the network includes a message identity (ID) in each SIB. The message ID is used for notifying the UE which notification message the current notification message content belongs to. The network segments the notification message to send the segment content via multiple SIBs, or send a complete notification message via an SIB without segmenting. 
     In addition, the process  80  includes the following steps: 
     Step  800 : Start. 
     Step  802 : Receive at least a SIB including content of the notification message and a message ID. 
     Step  804 : Generate the notification message with the content of the at least a received SIB according to the corresponding message ID. 
     Step  806 : End. 
     According to the process  80 , the UE receives the SIB/SIBs to acquire segment content or complete content of the notification message. Then, the UE generates the notification message with the content of the received SIB/SIBs according to the corresponding message ID/IDs. 
     When the notification message is sent with segments, the UE can find multiple same message IDs in the received SIBs and thereby combines the corresponding content to generate a complete notification message. When the notification message is sent without segmenting, the UE only finds a unique message ID different from the preceding one and the subsequent one. This means that the content with the unique message ID is the content of a complete notification message. 
     In the processes  70  and  80 , when the notification message is a secondary notification message, the SIB is SIB11. When the notification message is a primary notification message, the SIB is SIB10. 
     Alternatively, the message ID can be included in the content of the notification message. In this situation, when reading the currently received content, the UE knows which notification message the content belongs to. 
     Thus, with introduction of the message ID, the UE is able to distinguish the received notification messages to ensure the decoded content is correct. In addition, duplicate content can be detected. 
     Another usage of the message ID is that the UE determines whether the message content changes according to a change of the message ID. 
     Take a message ID sent via SIB11 for the secondary notification message for example. When the UE receives an SIB 11, the UE compares the message ID in the received SIB11 with a message ID previously stored in the UE. Please refer to  FIG. 12 , which illustrate flowcharts of a process  1200  according to an embodiment of the present invention. The process  1200  is utilized for handling a content change of a notification message corresponding to ETWS for an ETWS capable UE including a stored message ID. The  1200  can be compiled into the program code  214  of the process in the storage data  212 . The process  1200  includes the following steps: 
     Step  1202 : Start. 
     Step  1204 : Receive a SIB11 including a message ID in the cell. 
     Step  1206 : Determine whether the reception is the first time to receive SIB11 in the cell? If so, perform Step  1210 ; if not, perform Step  1208 . 
     Step  1208 : Compare the received message ID with the stored message ID to determine whether a message ID change occurs? If so, perform Step  1210 ; if not, perform Step  1212 . 
     Step  1210 : Store the message ID of the received SIB, discard any buffered secondary notification message segments, continue reception of the SIB11, and then perform Step  1218 . 
     Step  1212 : Determine whether a complete secondary notification message is received? If so, perform Step  1214 ; if not, perform Step  1212 . 
     Step  1214 : Discard the secondary notification message content of the received SIB11, stop reception of the SIB11 and then perform Step  1218 . 
     Step  1216 : Continue reception of the SIB11. 
     Step  1218 : End. 
     According to the process  1200 , the UE receives the SIB11 and determines whether the receipt of the SIB11 is the first time in the cell or not. When the UE first time receives the SIB11 in the cell, the UE stores the message ID of the received SIB, discards any buffered secondary notification message segment and continues reception of the SIB11. When the receipt is not the first time, the UE compares the received message ID with the previously stored message ID to determine a message ID change occurs. The UE stores the message ID, discards the secondary notification message content of the received SIB11 and further stops reception of the SIB when the received message ID is unchanged compared with the stored message ID, indicating a message ID change occurs. Otherwise, the UE turns to determine whether a complete secondary notification message is received. That is, the UE determines whether all message ID belonging to the complete secondary notification message is received. The UE discards the currently-received secondary notification message content and stops the reception of the SIB11; otherwise the UE continues reception of the SIB. 
     Through the process  1200 , the UE is able to discard any buffered secondary notification message segment and continue reception of the SIB11 when the UE first time receives the SIB11 in a cell. Therefore, the UE can avoid missing the new second notification message broadcasted by a new cell to which the UE reselects or selects. 
     On the other hand, the UE clears the stored message ID when the UE reselects or selects to another cell. The clearing of the stored message ID can be achieved by setting the stored message ID to a value that is not within a predetermined value range. For example, if the predetermined value range is 0 to 2, the UE can set the stored message ID to 3 for message ID clearing. Furthermore, the UE discards segments of the secondary notification message buffered in the UE when reselecting or selecting to another cell. 
     The cause for the UE to reselect or select to another cell can be cell reselection, a handover or a radio resource control connection re-establishment. 
     Please refer to  FIG. 9 , which illustrates a flowchart of a process  90  according to an embodiment of the present invention. The processes  90  is utilized for transmitting a notification message corresponding to ETWS for a network of a wireless communication system and can be compiled into the program code  214  of the process in the storage data  212 . The process  90  includes the following steps: 
     Step  900 : Start. 
     Step  902 : Modify scheduling information corresponding to a primary or secondary notification message. 
     Step  904 : Transmit the scheduling information before a paging message indicating existence of the primary notification message. 
     Step  906 : End. 
     According to the process  90 , the network modifies scheduling information corresponding to the primary or secondary notification message and transmits the modified scheduling information before the paging message to ensure that the UE can receive the primary notification message and the secondary notification message. 
     Take the primary notification message sent via the SIB10 and the secondary notification message sent via the SIB11 for example. The scheduling information is sent via the SIB1. The paging message indicating existence of the primary notification message is a paging message including an “etws-PrimaryNotificationIndication” for indicating changes of the SIB1. In this situation, the UE is certainly able to find the SIB1 changes after receiving the paging message. 
     Please refer to  FIG. 10 , which illustrates flowcharts of a process  1000  according to an embodiment of the present invention. The process  1000  is utilized for receiving a notification message corresponding to ETWS for a UE of a wireless communication system and can be compiled into the program code  214  of the process in the storage data  212 . The process  1000  includes the following steps: 
     Step  1002 : Start. 
     Step  1004 : When a paging message indicating existence of a primary notification message is received, start to acquire both the primary notification message and a secondary notification message according to scheduling information. 
     Step  1006 : End. 
     According to the process  1000 , the UE starts to acquire both the primary and secondary notification messages according to the scheduling information when receiving the paging message. 
     Preferably, the scheduling information for the primary and secondary notification messages is received from the SIB1. The paging message indicating existence of a primary notification message is a paging message including “etws-PrimaryNotificationIndication”. 
     In the prior art, the UE only starts to acquire the primary notification message when receiving the paging message including “etws-PrimaryNotificationIndication”, resulting in poor receiving efficiency of the secondary notification messages. Compared to the prior art, the UE using the process  1000  starts to acquire both the primary and secondary notification messages to allow the secondary notification messages to be received as soon as possible. 
     Preferably, the UE starts to acquire the secondary notification message in a known delay after the UE knows the start time of the secondary notification message transmission. 
     Take a system information broadcast providing modification periods for example. According to the scheduling information, the UE starts to acquire the secondary notification message at the beginning boundary of a modification period next to the modification period where the UE receives the paging message indicating the SIB1 change. 
     Please refer to  FIG. 11 , which illustrates a flowchart of a process  1100  according to an embodiment of the present invention. The processes  1100  is utilized for receiving a notification message corresponding to ETWS for a UE of a wireless communication system and can be compiled into the program code  214  of the process in the storage data  212 . The process  1100  includes the following steps: 
     Step  1102 : Start. 
     Step  1104 : Start to acquire a secondary notification message when a paging message including “etws-PrimaryNotificationIndication” is received at a modification period. 
     Step  1106 : Stop acquiring the secondary notification message at an ending boundary of the modification period when no scheduling information for the secondary notification message is received during the modification period. 
     Step  1108 : End. 
     According to the process  1100 , at the modification period where the paging message including “etws-PrimaryNotificationIndication” is received, the UE starts to acquire the secondary notification message. At the ending boundary of the modification period, the UE stops acquiring the secondary notification message when no scheduling information for the secondary notification message is received during the modification period. In other words, the UE does not continue acquiring the secondary notification message from the next modification period. 
     Through the process  1100 , the UE can detect whether any secondary notification message is broadcasted. If no scheduling information for secondary notification is published, the UE can save power on reception of the secondary notification message. 
     In conclusion, the embodiments of the present inventions handle the notification message reception and transmission corresponding to message content changes and receiving targets. 
     Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.