Earthquake and tsunami cellular warning system

TECHNICAL FIELD [0001] The invention discloses an improved method and corresponding devices for improving alerts in a cellular communication system.

BACKGROUND [0002] In the cellular communication project called 3GPP (Third Generation Partnership Project) the so-called Third Generation Partnership Project has been defined. ETWS system, Earthquake and Tsunami Warning System.

[0003] As the name implies, the ETWS function is to notify 3GPP system users of earthquakes, tsunamis and possibly other disasters, and to inform users about what to do.

[0004] ETWS thus contains two types of notifications, referred to as primary and supplementary notifications. The main purpose of the initial notification is to quickly alert users of an earthquake, tsunami or possibly other disasters, while the main purpose of the follow-up notification is to provide users with more information on, for example, steps to take, such as evacuation of buildings, etc.

[0005] Due to the nature and purpose of the ETWS system, the time requirements for providing the primary notification to users in a given area are strictly limited to 4 seconds, within this time limit the primary notification must be forwarded to all said users.

[0006] Furthermore, primary notifications transmitted in the ETWS system should have a built-in mechanism to prevent the transmission of ETWS messages by unauthorized users, in particular primary notification messages.

[0007] WO 2007/144872 discloses a cellular emergency notification service using messages sent to all available cellular devices in one or more selected cells.

SUMMARY [0008] As is apparent from the above description, there is a need for a solution that has enabled the ETWS system in a cellular communication system to send primary notifications to many users within a very limited time limit. In addition, the solution should enable the system to provide primary notifications in a secure manner to prevent unauthorized use of the system.

[0009] Such a solution is offered by the invention in such a way that it discloses according to claim 1 a method for use in a cellular communication system. The method of the invention includes the step of transmitting the defined ETWS message that it contains

- 2 original warning notification and verification information regarding the initial warning notification to user terminals in one or more system cells. The defined message is simultaneously transmitted to many user terminals in the system on the physical channel in the system, which is dedicated to messages for individual users.

[0010] In one embodiment of the invention, the physical channel used for messages is a paging channel in the system.

[0011] In one embodiment of the invention, the defined message causes the user terminals to listen for complementary warning notifications in subsequent messages on the same physical channel.

[0012] In one embodiment of the invention, the defined message is a type of message that identifies the defined message and causes the receiving user terminal to treat the defined message in a particular manner.

[0013] In one embodiment of the invention, the defined message is a type of message dedicated to the original warning notification and verification information.

[0014] In one embodiment, the initial warning notification and the verification information are included in the information elements in the defined message.

[0015] Accordingly, the method of the invention is applied to a cellular communication system of the type Broadband Code Division Multiple Access or WCDMA (Wideband Code Division Multiple Access) or system of the type Multiple Access with Synchronous Code and Time Division, TD SCDMA (Time) Division Synchronous Code Multiple Access).

[0016] The invention also discloses the ETWS system according to claim 8, the UE (User equipment) according to claim 13 in a cellular communication system using the invention.

BRIEF DESCRIPTION OF THE DRAWINGS [0017] The invention will be described in more detail below with reference to the accompanying drawings, in which

Figs. 1 and 2 show an overview of the system in which the invention is used, and Fig. 3 shows a block diagram in a first embodiment of the invention, and Fig. 4 shows a message according to a first embodiment of the invention, and Fig. 5 shows a block diagram in a second an embodiment of the invention, and Fig. 6 shows a message according to a second embodiment of the invention, and Fig. 7 shows a block diagram of a method according to the invention, and

Fig. 8 shows an RNC block diagram of the invention, and

Fig. 9 shows a UE block diagram according to the invention.

DETAILED DESCRIPTION [0018] In the following, the invention will be described using terminology from a cellular system called WCDMA, Code Division Broadband Multiple Access and a cellular system called TD SCDMA, Synchronous Code Multiple Access and Time Division. This is due to the fact that the invention is primarily intended for such systems, but the terminology should not be regarded as limiting the scope of protection required or granted to the invention, since the invention may also be used in other systems in which similar situations and problems occur.

[0019] Fig. 1 provides an overview of the system 100 in which the invention may be applied. System 100 is a cellular system and thus contains a plurality of cells, one of which, 105, is shown in Figure 1. Cell 105 can accommodate a plurality of user terminals, UE, one of which, 110, is shown as an example.

[0020] For each cell in the system, there is also a control node 115, NodeB, one of whose functions is to control traffic to and from the UE in cell 105. The system 100 also includes a Radio Network Controller, RNC (Radio Network Controller) 120, as well as the Node Operating Packet Transmission in the GSM and UMTS Systems Architecture, SGSN 125 and CBC 130 (Cell Broadcast Center). The functions and roles of RNC, SGSN and CBC are known to those of skill in the art and will not be described in detail here.

[0021] As mentioned earlier, the invention is directed to the Earthquake and Tsunami Warning System, ETWS, in a cellular system such as the system 100 in Fig.

1. The object of the invention is to enable the system operator 100 to transmit so-called ETWS primary warning notifications to users in one or more cells in the system as soon as possible, and undoubtedly within a time limit of four seconds. Initial warning notifications should also be transmitted securely so that improper use of the ETWS system is not possible.

[0022] In order to obtain the required forwarding speed of the initial warning notification, the invention uses a physical channel that the UE will often listen to in the cell, as opposed to physical channels that the UE listens less often. The physical channel used by the invention for transmitting the original warning notification is suitably the so-called paging channel, PCH, in system 100.

[0023] To obtain the security required for the ETWS system, the UE will, according to the invention, receive an ETWS authorization key that is used to verify that the original warning notification is true. The key is first granted to the UE, when the UE registers with SGSN for the first time.

[0024] Accordingly, the ETWS authorization key is changed or updated by the system at specified time intervals and stored by the UE between these time intervals. Optionally, to further increase security, users in different cells or groups of cells may receive different keys.

[0025] As already mentioned, for security reasons, periodic key replacement or updating may be required. For example, suppose a specific UE registers with SGSN at 23:50 local time and receives the key k1. Let's assume that the key is replaced with the key k2 at 00:00 local time.

[0026] Suppose further that at 00:05 an earthquake will occur that will generate the original warning notification at 00:09 local time. If this warning is protected by k2, the UE will not be able to verify it. Thus, you may need to send one and the same original warning notification twice, with different keys. This, on the other hand, can create confusion as to which message you should try to verify and which key. Therefore, a key pointer can be used. It can simply be a "version number" for a key that increases in a "cyclical" way each time the key is updated, eg w = 0, 1, 2, 0, 1, 2, 0.1. ... the EU receives the key version number and the version number is added in the message that contains the security information.

[0027] Turning now to the exact mechanism of how the initial warning notification is forwarded to the UE concerned, the system uses a (physical) paging channel to forward the original warning notification simultaneously in one or more cells, but uses the type of defined message for this purpose.

[0028] According to the invention, the UE is programmed to treat paging messages of this type of message as an ETWS message, and will notify the UE in a specific manner, or in a manner that has been defined in the message, e.g. to display the message on the UE screen, or to buzz if a text message (SMS) comes, etc.

[0029] Fig. 2 shows the situation with UE 110-113 in cell 105 of Fig. 1. The system operator 100 must send the original ETWS warning notification to UE 110-113 in cell 105:

[0030] The initial ETWS warning notification is initiated in CBC 130, which communicates this to RNC 120 (bypassing SGSN 125, which is transparent to the ETWS message). RNC 120 then sends the appropriate message to NodeB 115, which forwards the paging message of the defined message type to UE 110-113 in cell 110, [0031] The invention discloses two embodiments by which the initial ETWS warning notification and the accompanying verification information can be transferred to the EU. The first embodiment is illustrated in Fig. 3, where messages between different nodes in the system 100 are illustrated. Steps (arrows) 1 and 2,

- 5 are those that must be completed within the time limit for the initial ETWS warning notification.

1: The so-called write-change message is transmitted from CBC to RNS, using SGSN, which is "transparent" in this context.

2: RNC interprets the write-change message from the CBC as a command to forward the original ETWS warning notification to the UE in one or more cells that RNC "controls". In this embodiment, the message that is sent to the UE is a dedicated message, e.g., ETWS_Primary_Notification. The use of a dedicated message eliminates the need for the message to contain data such as, for example, MCC, Mobile Country Code, a number that identifies the country in which a given wireless telephony network operates) and MNC (Mobile Network Code, a unique number within a given country that identifies a wireless telephony network) that help speed up the transmission. The dedicated message also contains relevant informative verification. Steps 3-5 relate to the ETWS Supplementary Notification, but will be briefly described below:

3: RNC forwards the so-called BMC (Broadcast and Multicast Control, Schedule Message) to the UE terminal or UE terminals. BMC Schedule Message describes the place in time for each CBS BMC Message (Service Cell Broadcast) and the space during BMC Schedule Message in the next scheduled CBS.

4: The BMC CBS message, transmitted from the RNC to the UE terminal or UE terminals, carries the Supplementary Notification Message to the UE.

5: RNC reports to the CBC that it has received a warning message, possibly with additional information about the number of times the message was broadcast in a specific area. Such a report may differ between different systems, but may, for example, include "ACK" that the message was received by the RNC from the CBC, or may be "ACK" from the RNC when the RNC determined the number of times the NodeB broadcast the message in the area.

[0032] Fig. 4 is an exemplary embodiment of a dedicated message being forwarded from RNC 120 via NodeB 115 to UE 110-113. The message is the so-called RRC (Radio Resource Control) message with the fields shown in Fig. 4. The abbreviations in the RRC message fields in Fig. Should be interpreted as follows:

MP: Mandatory

CH: Addicted to history

OP: Optional [0033] As shown in Figure 4, the following fields are suggested in the RRC message:

- 6 • Message Type, MP • Integrity Check information, MP • ETWS information:

o warning type, MP with message ID, MP with serial number, MP • ETWS warning safety information, OP [0034] In this embodiment, as mentioned earlier, the message is sent on a physical channel, which is a paging channel, PCH (ang. Paging channel). The logical channel that is used for this purpose may be CCCH to UE in idle mode or URA_PCH, CELL_PCH or CELL_FACH combined mode. Alternatively, the message may be forwarded on the DCCH to the UE in the CELL_DCH linked mode state.

[0035] The second embodiment disclosed by the invention for transmitting the ETWS primary warning message and accompanying verification information is shown in Figure 5, with some arrows having the same numbers as in Figure 3, due to the similarity between the messages that are being sent.

[0036] The difference between the embodiments is the message sent from RNC to the UE, the message assigned the number 2 'in Fig. 5. The difference between the message 2' and the message 2 in Fig. 3 is that the message 2 'is not a message , which is dedicated to the ETWS original notification message. Instead, the message 2 'is a message on the paging channel in which the Information Elements, IE, which contain the ETWS original notification message and verification information are placed.

[0037] Fig 6 shows the following fields, which are included in an RRC message according to an embodiment:

• Message Type, MP, in this case CALL TYPE 1 • Paging register list, CH • Paging register, MP • BCCH modification, OP • ETWS information:

for information on ETWS warning type, MP for message ID, MP for serial number, MP • ETWS, OP warning safety information

[0038] As can be seen, only two of the IEs in the RRC message of Figure 6 relate to ETWS, and are essentially the same as those described in connection with Figure 3. Other IEs in the RRC message are well known to those skilled in the art and therefore they are not described here.

[0039] Fig. 7 is a block diagram of a method 700 according to the invention. Stages that are alternatives or options are represented by the dashed lines in Fig. 7.

[0040] As also discussed above, method 700 is intended for use in a cellular communication system such as the one shown in Fig. 1 and includes, as shown in step 705, a step of communicating to user terminals in one or more system cells a defined message that includes the initial warning notification, step 710 and verification information that relates to the original warning notification, step 715.

[0041] Step 720 illustrates that in one embodiment, the defined message causes user terminals to listen to complementary warning notifications in subsequent messages on the same physical channel, and step 725 shows that in one embodiment, the defined message is a type of message that identifies a defined message and causes the receiving user terminal to treat the defined message in a particular way.

[0042] Step 730 illustrates that in one embodiment, the defined message is a type of message dedicated to the initial warning notification and verification information, while step 735 illustrates that in one embodiment the original warning notification and verification information is contained in information items in the defined message.

[0043] As shown in step 740, the defined message is forwarded simultaneously to multiple user terminals on a physical channel in a system that is intended for single user messages, step 745.

[0044] Step 750 illustrates that in one embodiment, the physical channel used for the defined message is a paging channel in the system.

[0045] As mentioned earlier, method 700 is suitably used for a WCDMA system, i.e. Code Split Broadband Multiple Access or a TD SCDMA system, i.e. Synchronous Code Multiple Access and Time Division.

[0046] Fig. 8 is a block diagram of RNC 800, a Radio Network Controller, according to the invention, wherein Fig. 8 focuses mainly on those RNC 800 functions that have been added or changed by the invention.

[0047] The RNC according to the invention is adapted to receive Change Requests / Indications from CBC, which include the "ETWS paging indicator" parameter and the "Warning Type" parameter, and with or without the "Warning Safety Information" parameter. RNC 800 is adapted to process these Requests / indications from the CBC in such a way that it forwards them to the appropriate NodeB, specified by the CBC.

[0048] The requested e / indication Write-Change is processed by RNC 800 using one of the two methods described above as contained in the invention, i.e. it transfers information in Requests / Indications to NodeB in the type of dedicated message for the initial warning notification or verification information, or allows the inclusion of the initial warning notification and verification information in the information elements, IE, in the defined message. Regardless of which of the two alternatives used by the RNC 800 according to the invention is system dependent, both alternatives are within the scope of the invention.

[0049] The invention also discloses a UE, the block diagram of which is shown in Fig. 9, with reference number 900. Fig. 9 shows only those parts of UE 900 on which the invention primarily affects.

[0050] The UE 900 according to the invention comprises a function 905 for receiving messages on a physical channel, which is used for messages for individual users, such as a paging channel, PCH. In addition, UE 900 includes a function 910 for recognizing messages on the channel as ETWS messages, as opposed to, for example, paging messages or other messages that are typically forwarded on the physical channel in question. Such recognition is made by means of a message type as disclosed by one embodiment of the invention, or by identifying one or more separate IEs in a message as disclosed by another embodiment, both embodiments being described in detail. above in this text.

[0051] The invention is not limited to the embodiments described above and shown in the drawings, but can be easily modified within the scope of the appended claims.

Prepared and verified

Anna Stenzel

Patent Attorney