Title of Invention	EMERGENCY-INFORMATION RECEIVING METHOD, MOBILE STATION, AND RADIO BASE STATION
Abstract	An emergency-information receiving method according to the present invention includes: starting, at mobile stations (UE) , receiving scheduling-information-notification system information at a current modification period without waiting until a next modification period starts, when detecting a predetermined trigger; and receiving, at the mobile stations (UE), emergency-information-notification system information on the basis of scheduling information notified by the received scheduling-information-notification system information.

Title of Invention

EMERGENCY-INFORMATION RECEIVING METHOD, MOBILE STATION, AND RADIO BASE STATION

Abstract

An emergency-information receiving method according to the present invention includes: starting, at mobile stations (UE) , receiving scheduling-information-notification system information at a current modification period without waiting until a next modification period starts, when detecting a predetermined trigger; and receiving, at the mobile stations (UE), emergency-information-notification system information on the basis of scheduling information notified by the received scheduling-information-notification system information.

Full Text	Description EMERGENCY-INFORMATION RECEIVING METHOD, MOBILE STATION, AND RADIO BASE STATION Technical Field [0001] The present invention relates to an emergency-information receiving method in which a plurality of mobile stations receives emergency information in a mobile communication system in which a radio base station is configured to transmit a plurality of types of system information repeatedly within a modification period to the mobile stations via a broadcast channel, and to notify the mobile stations of a predetermined trigger via the broadcast channel regardless of the modification period. The present invention also relates to the mobile station and the radio base station. Background Art [0002] Heretofore, the "ETWS (Earthquake and Tsunami Warning System)", the "PWS (Public Warning System)", and the like have been known as systems to transmit emergency information to multiple mobile stations. [0003] Use of a SIB (System Information Block) on a broadcast channel (BCCH: Broadcast Control Channel) to transmit emergency information to multiple mobile stations has been considered for such "ETWS/PWS". [0004] In a conventional "ETWS/PWS", however, a radio base station is configured to transmit multiple types of system information (SIB1 to SIB8) repeatedly within a modification period (MP) . This causes a problem that, even if detecting occurrence of emergency information, the radio base station cannot make notification of the emergency information in the current modification period MP(n), and cannot transmit the emergency information until the next modification period MP(n+l) starts. Summary of" the Invention [0005] The present invention has been made in view of the above problem, and has an object to provide an emergency-information receiving method, a mobile station, and a radio base station which allow multiple mobile stations to receive emergency information as quickly as possible upon detection of occurrence of the emergency information. [0006] A first aspect of the present invention is summarized as an emergency-information receiving method in which a plurality of mobile stations receives emergency information in a mobile communication system in which a radio base station is configured to transmit a plurality of types of system information repeatedly within a modification period to the mobile stations via a broadcast channel, and to notify the mobile stations of a predetermined trigger via the broadcast channel regardless of the modification period, the method including the steps of: (A) starting, at the mobile stations, receiving scheduling-information-notification system information at a current modification period without waiting until a next modification period starts, when detecting the predetermined trigger; and (B) receiving, at the mobile stations, emergency-information-notification system information on the basis of scheduling information notified by the received scheduling-information-notification system information. [0007] In the first aspect, the emergency-information receiving method can further include a step of: (C) performing, at the mobile stations, processing corresponding to the emergency information notified by the received emergency-information-notification system information. [0008] A second aspect of the present invention is summarized as a mobile station configured to receive emergency information in a mobile communication system in which a radio base station is configured to transmit a plurality of types of system information repeatedly within a modification period to a plurality of mobile stations via a broadcast channel, and to notify the mobile stations of a predetermined trigger via the broadcast channel regardless of the modification period, the mobile station including: a scheduling-information-notification system information receiver unit configured to start receiving scheduling-information-notification system information at a current modification period without waiting until a next modification period starts, when detecting the predetermined trigger; and an emergency-information-notification system information receiver unit configured to receive emergency-information-notification system information on the basis of scheduling information notified by the received scheduling-information-notification system information. [0009] In the second aspect, the mobile station can further include: a processor unit configured to perform processing corresponding to the emergency information notified by the received emergency-information-notification system information. [0010] In the second aspect, the emergency-information-notification system information receiver unit can be configured to receive no scheduling information except the emergency-information-notification system information. [0011] In the second aspect, the scheduling-information-notification system information receiver unit can be configured to start receiving the scheduling-information-notif ication system information at the current modification period without waiting until the next modification period starts, when the mobile station is in an idle state or a communicating state, and when the scheduling-information-notification system information receiver unit detects a predetermined indicator included in a paging message as the predetermined trigger. [0012] In the second aspect, the scheduling-information-notification system information receiver unit can be configured to start receiving the scheduling-information-notification system information at the current modification period without waiting until the next modification period starts, when the mobile station is in an idle state or a communicating state, and when the scheduling-information-notification system information receiver unit detects a predetermined indicator as . the predetermined trigger via a physical downlink control channel including a paging identifier. [0013] In the second aspect, the scheduling-information-notification system information receiver can be configured to start receiving the scheduling-information-notification system information at the current modification period without waiting until the next modification period starts, when receiving a predetermined indicator as the predetermined trigger via a physical downlink control channel including a predetermined identifier. [0014] A third aspect of the present invention is summarized as a radio base station configured to transmit emergency information in a mobile communication system in which the radio base station is configured to transmit a plurality of types of system information repeatedly within a modification period to a plurality of mobile stations via a broadcast channel, and to notify the mobile stations of a predetermined trigger via the broadcast channel regardless of the modification period, the radio base station including: a scheduling-information-notification system information transmitter unit configured to notify, to the plurality of mobile stations, a predetermined trigger, and to transmit, to the plurality of mobile stations, scheduling-information-notification system information for notifying scheduling information which specifies a downlink resource for starting transmitting emergency-information-notification system information at a current modification period without waiting until a next modification period starts, when generation of the emergency information is detected; and an emergency-information-notification system information transmitter unit configured to transmit emergency-information-notification system information by using the downlink resource specified by the scheduling information. [0015] In the third aspect, the scheduling-information-notification system information transmitter unit can be configured to transmit, as the predetermined trigger, a predetermined indicator included in a paging message, to the mobile stations in an idle state or a communicating state. [0016] In the third aspect, the scheduling-information-notification system information transmitter unit can be configured to transmit, as the predetermined trigger, a predetermined indicator via a physical downlink control channel including a paging identifier, to the mobile stations in an idle state or a communicating state. [0017] In the third aspect, the scheduling-information-notification system information transmitter unit is configured to transmit, as the predetermined trigger; a predetermined indicator via a physical downlink control channel including a predetermined identifier. Brief Description of the Drawings [Fig. 1] Fig. 1 is an overall configurational view of a mobile communication system according to a first embodiment of the present invention. [Fig. 2] Fig. 2 is a functional block diagram of a radio base station according to the first embodiment of the present invention. [Fig. 3] Fig. 3 is a functional block diagram of a mobile station according to the first embodiment of the present invention. [Fig. 4] Fig. 4 is a diagram for explaining information transmitted on a BCCH by the radio base station according to the first embodiment of the present invention. [Fig. 5] Fig. 5 is a diagram showing an example of an "ETWS/PWS indicator" transmitted by the radio base station according to the first embodiment of the present invention. [Fig. 6] Fig. 6 is a diagram showing an example of the "ETWS/PWS indicator" transmitted by the radio base station according to the first embodiment of the present invention. [Fig. 7] Fig. 7 is a diagram showing an example of a PDCCH including the "ETWS/PWS indicator" transmitted by the radio base station according to the first embodiment of the present invention. [Fig. 8] Fig. 8 is a diagram showing an example of a PDCCH including an "ETWS/PWS-RNTI" transmitted by the radio base station according to the first embodiment of the present invention. [Fig. 9] Fig. 9 is a flowchart showing operation of the mobile station according to the first embodiment of the present invention. [Fig. 10] Fig. 10 is an overall configurational view of the mobile communication system according to Modification 1 of the present invention. [Fig. 11] Fig. 11 is a diagram showing an example of a PDCCH including an "ETWS/PWS-RNTI" transmitted by the radio base station according to Modification 1 of the present invention. [Fig. 12] Fig. 12 is a flowchart showing operation of the mobile station according to Modification 1 of the present invention. Best Mode for Carrying Out the Invention [0019] (Configuration of Mobile Communication System according to First Embodiment of Present Invention) With reference to Figs. 1 to 8, the configuration of a mobile communication system according to a first embodiment of the present invention will be described. [0020] As shown in Fig. 1, in the mobile communication system according to this embodiment, a radio base station eNB is configured to transmit multiple kinds of system information MIB (Master Information Block) and SIB1 to SIB9 repeatedly within a modification period MP, to multiple UEs via a broadcast channel BCCH. [0021] As shown in Fig. 2, the radio base station eNB includes an emergency information receiver unit 11 and an emergency information transmitter unit 12. [0022] The emergency information receiver unit 11 is configured to receive emergency information transmitted by an emergency information notification system, in other words, to detect occurrence of emergency information. [0023] The emergency information transmitter unit 12 is configured to transmit the emergency information to the multiple mobile stations UE via the broadcast channel BCCH. [0024] Specifically, the emergency.information transmitter unit 12 is configured to notify the multiple mobile stations UE of a predetermined trigger, and to start transmitting scheduling-information-notification system information (MIB/SIB1) to the multiple mobile stations UE at the current modification period MP(n) without waiting until the next modification period MP(n+l) starts, when the emergency information receiver unit 11 receives emergency information, in other words, when the emergency information receiver unit 11 detects occurrence of emergency information. The scheduling-information-notification system information is used for notification of scheduling information which specifies a downlink resource for transmitting emergency-information-notification system information (e.g., SIB9). [0025] The emergency information transmitter unit 12 is also configured to transmit the emergency-information-notification system information (e.g., SIB9) by using the downlink resource specified by the scheduling information. [0026] As shown in Fig. 3, each of the mobile stations UE includes an emergency information receiver unit 21 and a processor unit 22. [0027] The emergency information receiver unit 21 is configured to receive emergency information transmitted by the radio base station eNB via the broadcast channel BCCH. [0028] Specifically, as shown in Fig. 4, the emergency information receiver unit 21 is configured to start receiving the scheduling-information-notification system information (MIB/SIB1) at the current modification period MP(n) without waiting until the next modification period MP (n+1) starts, when detecting the predetermined trigger. [0029] The emergency information receiver unit 21 is also configured to receive the emergency-information-notification system information (e.g., SIB9) on the basis of the scheduling information notified by the received scheduling-information-notification system information (MIB/SIB1). [0030] It should be noted in this case that the emergency- information receiver unit 21 may be configured not to receive scheduling information (SIB2 to SIB8) except the emergency-information-notification system information (e.g., SIB9). [0031] Here, the emergency information receiver unit 21 may be configured to start receiving the scheduling-information-notification system information (MIB/SIB1) at the current modification period MP(n) without waiting until the next modification period MP (n+1) starts, when the mobile station UE is in an idle state or a communicating state, and when the emergency information receiver unit 21 detects a predetermined indicator (ETWS/PWS indicator) included in a paging message as the predetermined trigger. [0032] As shown in Fig. 5, the paging message is transmitted via a PDSCH (Physical Downlink Shared Channel) corresponding to a P-RNTI via a PDCCH (Physical Downlink Control Channel) . [0033] For example, the predetermined indicator (ETWS/PWS indicator) is a 1-bit indicator used for notification of the presence or absence of emergency information, or is primary notification (which is short information to be notified of first as to the emergency information and is used to ring mobile stations or the like). [0034] In other words, the emergency information transmitter unit 12 of the radio base station eNB may be configured to transmit, as the predetermined trigger, the predetermined indicator (ETWS/PWS indicator) in a paging message, to the mobile stations UE in an idle state or a radio-link established state (RRC_connected state). [0035] In addition, the emergency information receiver unit 21 may also be configured to start receiving the scheduling-information-notification system information (MIB/SIB1) at the current modification period MP(n) without waiting until the next modification period MP (n+1) starts', when the mobile station UE is in an idle state or a communicating state, and when the emergency information receiver unit 21 detects a predetermined indicator (ETWS/PWS indicator) as the predetermined trigger via a PDCCH (Physical Downlink Control Channel) including a P-RNTI (Paging-RNTI) as shown in Fig. 6. [0036] For example, the predetermined indicator (ETWS/PWS indicator) is a 1-bit indicator used for notification of the presence or absence of emergency information, or is primary notification (which is short information to be notified of first as to the emergency information and is used to ring mobile stations). [0037] In other words, the emergency information transmitter unit 12 of the radio base station eNB may be configured to transmit, as the predetermined trigger, the predetermined indicator (ETWS/PWS indicator) via the PDCCH (Physical Downlink Control Channel) including the P-RNTI (Paging-RNTI), to mobile stations UE in an idle state or a radio-link established state (RRC_connected state). [0038] Additionally, the emergency information receiver unit 21 may also be configured to start receiving the scheduling-information-notification system information (MIB/SIB1) at the current modification period MP(n) without waiting until the next modification period MP (n+1) starts, when the mobile station UE is in a radio-link established state (RRC_connected state) or an idle state, and when the emergency information receiver unit 21 detects a predetermined indicator (ETWS/PWS indicator) as the predetermined trigger via a PDCCH (Physical Downlink Control Channel) including an SC-RNTI (System Change-RNTI, i.e., predetermined identifier) as shown in Fig. 7. [0039] For example, the predetermined indicator (ETWS/PWS indicator) is a 1-bit indicator used for notification of the presence or absence of emergency information, or is primary notification (which is short information to be notified of first as to the emergency information and is used to ring mobile stations or the like). [0040] In other words, the emergency information transmitter unit 12 of the radio base station eNB may be configured to transmit, as the predetermined trigger, the predetermined indicator (ETWS/PWS indicator) via the PDCCH (Physical Downlink Control Channel) including the SC-RNTI (System Change-RNTI, i.e., predetermined identifier), to mobile stations UE in an idle state or a radio-link established state (RRC connected state) . [0041] In addition, the emergency information receiver unit 21 may also be configured to start receiving the scheduling-information-notification system information (MIB/SIB1) at the current modification period MP(n) without waiting until the next modification periodMP (n+1) starts, when detecting a PDCCH (Physical Downlink Control Channel) including an ETWS/PWS-RNTI (predetermined identifier) as the predetermined trigger as shown in Fig. 8. [0042] In other words, the emergency information transmitter unit 12 of the radio base station eNB may be configured to transmit, as the predetermined trigger, predetermined information via the PDCCH (Physical Downlink Control Channel) including the ETWS/PWS-RNTI (predetermined identifier). [0043] The processor unit 22 is configured to perform processing corresponding to the emergency information notified by the received emergency-information-notification system information (e.g., SIB9). [0044] For example, as the processing corresponding to the emergency information, the processor unit 22 may output an alarm corresponding to the emergency information, or show textual information or image information corresponding to the emergency information, on a display. [0045] (Operation of Mobile Communication System according to First Embodiment of Present Invention) With reference to Fig. 9, operation of the mobile station according the first embodiment of the present invention will be described. [0046] As shown in Fig. 9, in Step S101, the mobile station UE detects a PDCCH including an ETWS/PWS-RNTI, or an ETWS/PWS indicator. [0047] In Step S102, the mobile station UE starts receiving the MIB/SIB9 at the current modification period MP(n) without waiting until the next modification period MP(n+l) starts. [0048] In Step S103, the mobile station UE receives the SIB9 on the basis of scheduling information notified by the received MIB/SIB1,and then performs processing (e.g., using an alarm, display, or the like) corresponding to emergency information notified by the SIB9. [0049] (Advantageous Effect of Mobile Communication System according to First Embodiment of Present Invention) With the mobile communication system according to the first embodiment of the present invention, when detecting a predetermined trigger, a mobile station UE starts receiving the MIB/SIB1 at the current modification period MP(n) without waiting until the next modification period MP (n+1) starts, and then receives the SIB9 for notification of emergency information, on the basis of the MIB/SIB1. Accordingly, multiple mobile stations UE can be notified of generated emergency information as quickly as possible. [0050] (Modification) With reference to Figs. 10 to 12, the mobile communication system according to Modification 1 of the present invention will be described while attention is focused on the difference from the mobile communication system according to the first embodiment described above. [0051] As shown in Fig. 10, in the mobile communication system according to Modification 1, the radio base station eNB is configured to transmit emergency information to multiple mobile stations UE via a common traffic channel CTCH. [0052] The emergency information transmitter unit 12 of the radio base station eNB according to Modification 1 is configured to transmit emergency information to the multiple mobile stations UE via the common traffic channel CTCH. [0053] Specifically, the emergency information transmitter unit 12 is configured to notify the multiple mobile stations UE of a predetermined indicator (ETWS/PWS indicator) , and to transmit the emergency information to the multiple mobile stations UE via a downlink resource (the CTCH on a PDSCH (Physical Downlink Shared Channel)) specified by a physical downlink control channel (PDCCH) including a predetermined identifier (ETWS/PWS-RNTI), when the emergency information receiver unit 11 receives emergency information, in other words, when the emergency information receiver unit 11 detects occurrence of emergency information. [0054] In addition, the emergency information receiver unit 21 of the mobile station UE according to Modification 1 is configured to receive the emergency information transmitted by the radio base station eNB via the common traffic channel CTCH. [0055] Specifically, the emergency information receiver unit 21 is configured to start monitoring the physical downlink control channel (PDCCH) including the predetermined indicator (ETWS/PWS-RNTI), when detecting the predetermined indicator (ETWS/PWS indicator) . The emergency information receiver unit 21 is configured to receive the emergency information via the downlink resource (the CTCH on the PDSCH) specified by the physical downlink control channel (PDCCH), when detecting the physical downlink control channel (PDCCH). [0056] Here, the emergency information receiver unit'21 may be configured to start monitoring the physical downlink control channel (PDCCH) including the predetermined identifier (ETWS/PWS-RNTI) , when the mobile station UE is in an idle state or a radio-link established state (RRC_connected state, i.e., communicating state), and when the emergency information receiver unit 21 detects the predetermined indicator (ETWS/PWS indicator) in a paging message. [0057] Specifically, the emergency information receiver unit 21 may be configured to start monitoring the physical downlink control channel (PDCCH) including the predetermined identifier (ETWS/PWS-RNTI) , when the mobile station UE is in an idle state or a radio-link established state (RRC_connected state, i.e., communicating state), and when the emergency information receiver unit 21 receives the predetermined indicator (ETWS/PWS indicator) via a physical downlink control channel including a paging identifier, that is, when the emergency information receiver unit 21 detects the predetermined indicator. [0058] As shown in Fig. 6, the emergency information receiver unit 21 may be configured to start monitoring the physical downlink control channel (PDCCH) including the predetermined identifier (ETWS/PWS-RNTI), when receiving the predetermined indicator (ETWS/PWS indicator) via a PDCCH (predetermined Physical Downlink Control Channel) including a P-RNTI (Paging-RNTI) , in other words, when detecting the predetermined indicator. [0059] In addition, the emergency information receiver unit 21 may be configured to start monitoring the physical downlink control channel (PDCCH) including the-predetermined identifier (ETWS/PWS-RNTI), when the mobile station UE is in a radio-link established state (RRC_connected state) or an idle state, and when the emergency information receiver unit 21 detects the predetermined indicator (ETWS/PWS indicator) via a PDCCH (predetermined Physical Downlink Control Channel) including an SC-RNTI (System Change-RNTI, i.e., predetermined identifier) as shown in Fig. 7. [0060] As shown in Fig. 11, the emergency information is transmitted via the downlink resource (the CTCH on the PDSCH) specified by the physical downlink control channel (PDCCH) including the predetermined identifier (ETWS/PWS-RNTI). [0061] With reference to Fig. 12, operation of the mobile station UE according to Modification 1 will be described. [0062] As shown in Fig. 12, in Step S201, the mobile station UE detects an ETWS/PWS indicator. [0063] In Step S202, the mobile station UE starts monitoring a physical downlink control channel (PDCCH) including an ETWS/PWS-RNTI. [0064] In Step S203, the mobile station UE detects the physical downlink control channel (PDCCH) including the ETWS/PWS-RNTI. [0065] In Step S204, the mobile station UE receives emergency information via a downlink resource (a CTCH on a PDSCH) specified by the physical downlink control channel (PDCCH) , and then performs processing (e.g., using an alarm, display, or the like) corresponding to the emergency information. [0066] In the mobile communication system according to Modification 1, the mobile station UE is configured to start monitoring a physical downlink control channel (PDCCH) including an ETWS/PWS-RNTI, when detecting a predetermined indicator (ETWS/PWS indicator). When detecting the physical downlink control channel (PDCCH) including the ETWS/PWS-RNTI, then the mobile station UE is configured to receive emergency information via a downlink resource specified by the physical downlink control channel (PDCCH). Accordingly,. multiple mobile stations UE can be notified of generated emergency information as quickly as possible. Note that the features of Modification 1 described above can be expressed as follows. [0067] The first aspect of Modification 1 is summarized as an emergency-information notification method in which a radio base station eNB notify multiple mobile stations UE of emergency information, the method including the steps of: (A) starting, at the mobile stations UE, monitoring a physical downlink control channel including a predetermined identifier, when a predetermined indicator is detected; (B) receiving, at the mobile stations UE, the emergency information via a downlink resource specified by the physical downlink control channel, when the mobile stations UE detect the physical downlink control channel; and (C) performing, at the mobile stations UE, processing corresponding to the received emergency information. [0068] The second aspect of Modification 1 is summarized as a mobile station UE configured to receive emergency information transmitted by a radio base station eNB, the mobile station UE including: an emergency-information receiver unit configured to start monitoring a physical downlink control channel including a predetermined identifier when detecting a predetermined indicator, and to receive the emergency information via a downlink resource specified by the physical downlink control channel when detecting the physical downlink control channel; and a processor unit configured to perform processing corresponding to the received emergency information. [0069] In the second aspect of Modification 1, the emergency information receiver unit may be configured to start monitoring the physical downlink control channel, when the mobile station UE is in an idle state or a communicating state, and when the emergency information receiver unit detects the predetermined indicator in a paging message. [0070] In the second aspect of Modification 1, the emergency information receiver unit may be configured to start monitoring the physical downlink control channel, when the mobile station UE is in an idle state or a comifiunieating state, and when the emergency information receiver unit receives the predetermined indicator via a physical downlink control channel including a paging identifier. [0071] In the second aspect of Modification 1, the emergency information receiver unit may be configured to start monitoring the physical downlink control channel, when receiving the predetermined indicator via a predetermined physical downlink control channel. [0072] The third aspect of Modification 1 is summarized as a radio base station eNB configured to transmit emergency information to multiple mobile stations UE, the radio base station eNB including: an emergency information transmitter unit configured to notify the multiple mobile stations UE of a predetermined indicator, and to transmit the emergency information to the multiple mobile stations UE via a downlink resource specified by a physical downlink control channel including a predetermined identifier, when detecting occuirrence of the emergency information. [0073] In the third aspect of Modification 1, the emergency information transmitter unit may be configured to transmit the predetermined indicator included in a paging message, to the mobile stations UE in an idle state or communicating state. [0074] In the third aspect of Modification 1, the emergency information transmitter unit may be configured to transmit the predetermined indicator via a physical downlink control channel including a paging identifier, to the mobile stations UE in an idle state or communicating state. [0075] In the third aspect of Modification 1, the emergency information transmitter unit may be configured to transmit the predetermined indicator via a predetermined physical downlink control channel. [0076] Note that operation of the above described mobile station UE and of the radio base station eNB may be implemented by means of hardware, a software module executed by a processor, or a combination of both. [0077] The software module may be provided in any type of storage medium such as an RAM (Random Access Memory) , a flash memory, a ROM (Read Only Memory) , an EPROM (Erasable Programmable ROM) , an EEPROM (Electronically Erasable and Programmable ROM), a register, a hard disk, a removable disk, or a CD-ROM. [0078] The storage medium is connected to the processor so that the processor can read and write information from and to the storage medium. Also, the storage medium may be integrated into the processor. Also, the storage medium and the processor may be provided in an ASIC. The ASIC may be provided in the mobile station UE and the radio base station eNB. Also, the storage medium and the processor may be provided in the mobile station UE and the radio base station eNB as a discrete component. [0079] Hereinabove, the present invention has been described in detail using the above embodiment; however, it is apparent to those skilled in the art that the present invention is not limited to the embodiment described herein. Modifications and variations of the present invention can be made without departing from the spirit and scope of the present invention defined by the description of the scope of claims. Thus, what is described herein is for illustrative purpose, and has no intention whatsoever to limit the present invention. Industrial Applicability [0080] As has been described above, with the present invention, it is possible to provide an emergency-information receiving method, a mobile station, and a radio base station which allow a plurality of the mobile stations to receive emergency information as quickly as possible upon detection of occurence of the emergency information. Claims 1. An emergency-information receiving method in which a plurality of mobile stations receives emergency information in a mobile communication system in which a radio base station is configured to transmit a plurality of types of system information repeatedly within a modification period to the mobile stations via a broadcast channel, and to notify the mobile stations of a predetermined trigger via the broadcast channel regardless of the modification period, the method comprising the steps of: (A) starting, at the mobile stations, receiving scheduling-information-notification system information at a current modification period without waiting until a next modification period starts, when detecting the predetermined trigger; and (B) receiving, at the mobile stations, emergency-information-notification system information on the basis of scheduling information notified by the received scheduling-information-notification system information. 2. The emergency-information receiving method according to claim 1, further comprising a step of: (C) performing, at the mobile stations, processing corresponding to the emergency information notified by the received emergency-information-notification system information. 3. A mobile station configured to receive emergency information in a mobile communication system in which a radio base station is configured to transmit a plurality of types of system information repeatedly within a modification period to a plurality of mobile stations via a broadcast channel, and to notify the mobile stations of a predetermined trigger via the broadcast channel regardless of the modification period, the mobile station comprising: a scheduling-information-notification system information receiver unit configured to start receiving scheduling-information-notification system information at a current modification period without waiting until a next modification period starts, when detecting the predetermined trigger; and an emergency-information-notification system information receiver unit configured to receive emergency-information-notification system information on the basis of scheduling information notified by the received scheduling-information-notification system information. 4. The mobile station according to claim 3, further comprising: a processor unit configured to perform processing corresponding to the emergency information notified by the received emergency-information-notification system information. 5. The mobile station according to claim 3, wherein the emergency-information-notification system information receiver unit is configured to receive no scheduling information except the emergency-information-notification system information. 6. The mobile station according to claim 3, wherein the scheduling-information-notification system information receiver unit is configured to start receiving the scheduling-information-notification system information at the current modification period without waiting until the next modification period starts, when the mobile station is in an idle state or a communicating state, and when the scheduling-information-notification system information receiver unit detects a predetermined indicator included in a paging message as the predetermined trigger. 7. The mobile station according to claim 3, wherein the scheduling-information-notification system information receiver unit is configured to start receiving the scheduling-information-notif ication system information at the current modification period without waiting, until the next modification period starts, when the mobile station is in an idle state or a communicating state, and when the scheduling-information-notification system information receiver unit receives a predetermined indicator as the predetermined trigger via a physical downlink control channel including a paging identifier. 8. The mobile station according to claim 3, wherein the scheduling-information-notification system information receiver is configured to start receiving the scheduling-information-notification system information at the current modification period without waiting until the next modification period starts, when receiving a predetermined indicator as the predetermined trigger via a physical downlink control channel. 9. A radio base station configured to transmit emergency information in a mobile communication system in which the radio base station is configured to transmit a plurality of types of system information repeatedly within a modification period to a plurality of mobile stations via a broadcast channel, and to notify the mobile stations of a predetermined trigger via the broadcast channel regardless of the modification period, the radio base station comprising: a scheduling-information-notification system information transmitter unit configured to notify, to the plurality of mobile stations, a predetermined trigger, and to start transmitting, to the plurality of mobile stations, scheduling-information-notification system information for notifying scheduling information which specifies a downlink resource for transmitting emergency-information-notification system information at a current modification period without waiting until a next modification period starts, when generation of the emergency information is detected; and an emergency-information-notification system information transmitter unit configured to transmit emergency-information-notification system information by using the downlink resource specified by the scheduling information. 10. The radio base station according to claim 9, wherein the scheduling-information-notification system information transmitter unit is configured to start transmitting, as the predetermined trigger, a predetermined indicator included in a paging message, to the mobile stations in an idle state or a communicating state. 11. The radio base station according to claim 9, wherein the scheduling-information-notification system information transmitter unit is configured to transmit, as the predetermined trigger, a predetermined indicator via a physical downlink channel including a paging identifier, to the mobile stations in an idle state or a communicating state. 12. The radio base station according to claim 9, wherein the scheduling-information-notification system information transmitter unit is configured to transmit, as the predetermined trigger, a predetermined indicator via a physical downlink control channel including a predetermined identifier. An emergency-information receiving method according to the present invention includes: starting, at mobile stations (UE) , receiving scheduling-information-notification system information at a current modification period without waiting until a next modification period starts, when detecting a predetermined trigger; and receiving, at the mobile stations (UE), emergency-information-notification system information on the basis of scheduling information notified by the received scheduling-information-notification system information.

Full Text

Description
EMERGENCY-INFORMATION RECEIVING METHOD, MOBILE STATION, AND
RADIO BASE STATION
Technical Field
[0001]
The present invention relates to an
emergency-information receiving method in which a plurality of
mobile stations receives emergency information in a mobile
communication system in which a radio base station is configured
to transmit a plurality of types of system information
repeatedly within a modification period to the mobile stations
via a broadcast channel, and to notify the mobile stations of
a predetermined trigger via the broadcast channel regardless
of the modification period. The present invention also relates
to the mobile station and the radio base station.
Background Art
[0002]
Heretofore, the "ETWS (Earthquake and Tsunami Warning
System)", the "PWS (Public Warning System)", and the like have
been known as systems to transmit emergency information to
multiple mobile stations.
[0003]
Use of a SIB (System Information Block) on a broadcast
channel (BCCH: Broadcast Control Channel) to transmit emergency
information to multiple mobile stations has been considered for
such "ETWS/PWS".
[0004]

In a conventional "ETWS/PWS", however, a radio base
station is configured to transmit multiple types of system
information (SIB1 to SIB8) repeatedly within a modification
period (MP) . This causes a problem that, even if detecting
occurrence of emergency information, the radio base station
cannot make notification of the emergency information in the
current modification period MP(n), and cannot transmit the
emergency information until the next modification period
MP(n+l) starts.
Summary of" the Invention
[0005]
The present invention has been made in view of the above
problem, and has an object to provide an emergency-information
receiving method, a mobile station, and a radio base station
which allow multiple mobile stations to receive emergency
information as quickly as possible upon detection of occurrence
of the emergency information.
[0006]
A first aspect of the present invention is summarized as
an emergency-information receiving method in which a plurality
of mobile stations receives emergency information in a mobile
communication system in which a radio base station is configured
to transmit a plurality of types of system information
repeatedly within a modification period to the mobile stations
via a broadcast channel, and to notify the mobile stations of
a predetermined trigger via the broadcast channel regardless
of the modification period, the method including the steps of:
(A) starting, at the mobile stations, receiving

scheduling-information-notification system information at a
current modification period without waiting until a next
modification period starts, when detecting the predetermined
trigger; and (B) receiving, at the mobile stations,
emergency-information-notification system information on the
basis of scheduling information notified by the received
scheduling-information-notification system information.
[0007]
In the first aspect, the emergency-information receiving
method can further include a step of: (C) performing, at the
mobile stations, processing corresponding to the emergency
information notified by the received
emergency-information-notification system information.
[0008]
A second aspect of the present invention is summarized
as a mobile station configured to receive emergency information
in a mobile communication system in which a radio base station
is configured to transmit a plurality of types of system
information repeatedly within a modification period to a
plurality of mobile stations via a broadcast channel, and to
notify the mobile stations of a predetermined trigger via the
broadcast channel regardless of the modification period, the
mobile station including: a
scheduling-information-notification system information
receiver unit configured to start receiving
scheduling-information-notification system information at a
current modification period without waiting until a next
modification period starts, when detecting the predetermined
trigger; and an emergency-information-notification system

information receiver unit configured to receive
emergency-information-notification system information on the
basis of scheduling information notified by the received
scheduling-information-notification system information.
[0009]
In the second aspect, the mobile station can further
include: a processor unit configured to perform processing
corresponding to the emergency information notified by the
received emergency-information-notification system
information.
[0010]
In the second aspect, the
emergency-information-notification system information
receiver unit can be configured to receive no scheduling
information except the emergency-information-notification
system information.
[0011]
In the second aspect, the
scheduling-information-notification system information
receiver unit can be configured to start receiving the
scheduling-information-notif ication system information at the
current modification period without waiting until the next
modification period starts, when the mobile station is in an
idle state or a communicating state, and when the
scheduling-information-notification system information
receiver unit detects a predetermined indicator included in a
paging message as the predetermined trigger.
[0012]
In the second aspect, the

scheduling-information-notification system information
receiver unit can be configured to start receiving the
scheduling-information-notification system information at the
current modification period without waiting until the next
modification period starts, when the mobile station is in an
idle state or a communicating state, and when the
scheduling-information-notification system information
receiver unit detects a predetermined indicator as . the
predetermined trigger via a physical downlink control channel
including a paging identifier.
[0013]
In the second aspect, the
scheduling-information-notification system information
receiver can be configured to start receiving the
scheduling-information-notification system information at the
current modification period without waiting until the next
modification period starts, when receiving a predetermined
indicator as the predetermined trigger via a physical downlink
control channel including a predetermined identifier.
[0014]
A third aspect of the present invention is summarized as
a radio base station configured to transmit emergency
information in a mobile communication system in which the radio
base station is configured to transmit a plurality of types of
system information repeatedly within a modification period to
a plurality of mobile stations via a broadcast channel, and to
notify the mobile stations of a predetermined trigger via the
broadcast channel regardless of the modification period, the
radio base station including: a

scheduling-information-notification system information
transmitter unit configured to notify, to the plurality of
mobile stations, a predetermined trigger, and to transmit, to
the plurality of mobile stations,
scheduling-information-notification system information for
notifying scheduling information which specifies a downlink
resource for starting transmitting
emergency-information-notification system information at a
current modification period without waiting until a next
modification period starts, when generation of the emergency
information is detected; and an
emergency-information-notification system information
transmitter unit configured to transmit
emergency-information-notification system information by
using the downlink resource specified by the scheduling
information.
[0015]
In the third aspect, the
scheduling-information-notification system information
transmitter unit can be configured to transmit, as the
predetermined trigger, a predetermined indicator included in
a paging message, to the mobile stations in an idle state or
a communicating state.
[0016]
In the third aspect, the
scheduling-information-notification system information
transmitter unit can be configured to transmit, as the
predetermined trigger, a predetermined indicator via a physical
downlink control channel including a paging identifier, to the

mobile stations in an idle state or a communicating state.
[0017]
In the third aspect, the
scheduling-information-notification system information
transmitter unit is configured to transmit, as the
predetermined trigger; a predetermined indicator via a physical
downlink control channel including a predetermined identifier.
Brief Description of the Drawings
[Fig. 1] Fig. 1 is an overall configurational view of a
mobile communication system according to a first embodiment of
the present invention.
[Fig. 2] Fig. 2 is a functional block diagram of a radio base
station according to the first embodiment of the present
invention.
[Fig. 3] Fig. 3 is a functional block diagram of a mobile
station according to the first embodiment of the present
invention.
[Fig. 4] Fig. 4 is a diagram for explaining information
transmitted on a BCCH by the radio base station according to
the first embodiment of the present invention.
[Fig. 5] Fig. 5 is a diagram showing an example of an
"ETWS/PWS indicator" transmitted by the radio base station
according to the first embodiment of the present invention.
[Fig. 6] Fig. 6 is a diagram showing an example of the
"ETWS/PWS indicator" transmitted by the radio base station
according to the first embodiment of the present invention.
[Fig. 7] Fig. 7 is a diagram showing an example of a PDCCH
including the "ETWS/PWS indicator" transmitted by the radio

base station according to the first embodiment of the present
invention.
[Fig. 8] Fig. 8 is a diagram showing an example of a PDCCH
including an "ETWS/PWS-RNTI" transmitted by the radio base
station according to the first embodiment of the present
invention.
[Fig. 9] Fig. 9 is a flowchart showing operation of the
mobile station according to the first embodiment of the present
invention.
[Fig. 10] Fig. 10 is an overall configurational view of the
mobile communication system according to Modification 1 of the
present invention.
[Fig. 11] Fig. 11 is a diagram showing an example of a PDCCH
including an "ETWS/PWS-RNTI" transmitted by the radio base
station according to Modification 1 of the present invention.
[Fig. 12] Fig. 12 is a flowchart showing operation of the
mobile station according to Modification 1 of the present
invention.
Best Mode for Carrying Out the Invention
[0019]
(Configuration of Mobile Communication System according to
First Embodiment of Present Invention)
With reference to Figs. 1 to 8, the configuration of a
mobile communication system according to a first embodiment of
the present invention will be described.
[0020]
As shown in Fig. 1, in the mobile communication system
according to this embodiment, a radio base station eNB is

configured to transmit multiple kinds of system information MIB
(Master Information Block) and SIB1 to SIB9 repeatedly within
a modification period MP, to multiple UEs via a broadcast
channel BCCH.
[0021]
As shown in Fig. 2, the radio base station eNB includes
an emergency information receiver unit 11 and an emergency
information transmitter unit 12.
[0022]
The emergency information receiver unit 11 is configured
to receive emergency information transmitted by an emergency
information notification system, in other words, to detect
occurrence of emergency information.
[0023]
The emergency information transmitter unit 12 is
configured to transmit the emergency information to the
multiple mobile stations UE via the broadcast channel BCCH.
[0024]
Specifically, the emergency.information transmitter unit
12 is configured to notify the multiple mobile stations UE of
a predetermined trigger, and to start transmitting
scheduling-information-notification system information
(MIB/SIB1) to the multiple mobile stations UE at the current
modification period MP(n) without waiting until the next
modification period MP(n+l) starts, when the emergency
information receiver unit 11 receives emergency information,
in other words, when the emergency information receiver unit
11 detects occurrence of emergency information. The
scheduling-information-notification system information is

used for notification of scheduling information which specifies
a downlink resource for transmitting
emergency-information-notification system information (e.g.,
SIB9).
[0025]
The emergency information transmitter unit 12 is also
configured to transmit the emergency-information-notification
system information (e.g., SIB9) by using the downlink resource
specified by the scheduling information.
[0026]
As shown in Fig. 3, each of the mobile stations UE includes
an emergency information receiver unit 21 and a processor unit
22.
[0027]
The emergency information receiver unit 21 is configured
to receive emergency information transmitted by the radio base
station eNB via the broadcast channel BCCH.
[0028]
Specifically, as shown in Fig. 4, the emergency
information receiver unit 21 is configured to start receiving
the scheduling-information-notification system information
(MIB/SIB1) at the current modification period MP(n) without
waiting until the next modification period MP (n+1) starts, when
detecting the predetermined trigger.
[0029]
The emergency information receiver unit 21 is also
configured to receive the emergency-information-notification
system information (e.g., SIB9) on the basis of the scheduling
information notified by the received

scheduling-information-notification system information
(MIB/SIB1).
[0030]
It should be noted in this case that the emergency-
information receiver unit 21 may be configured not to receive
scheduling information (SIB2 to SIB8) except the
emergency-information-notification system information (e.g.,
SIB9).
[0031]
Here, the emergency information receiver unit 21 may be
configured to start receiving the
scheduling-information-notification system information
(MIB/SIB1) at the current modification period MP(n) without
waiting until the next modification period MP (n+1) starts, when
the mobile station UE is in an idle state or a communicating
state, and when the emergency information receiver unit 21
detects a predetermined indicator (ETWS/PWS indicator)
included in a paging message as the predetermined trigger.
[0032]
As shown in Fig. 5, the paging message is transmitted via
a PDSCH (Physical Downlink Shared Channel) corresponding to a
P-RNTI via a PDCCH (Physical Downlink Control Channel) .
[0033]
For example, the predetermined indicator (ETWS/PWS
indicator) is a 1-bit indicator used for notification of the
presence or absence of emergency information, or is primary
notification (which is short information to be notified of first
as to the emergency information and is used to ring mobile
stations or the like).

[0034]
In other words, the emergency information transmitter
unit 12 of the radio base station eNB may be configured to
transmit, as the predetermined trigger, the predetermined
indicator (ETWS/PWS indicator) in a paging message, to the
mobile stations UE in an idle state or a radio-link established
state (RRC_connected state).
[0035]
In addition, the emergency information receiver unit 21
may also be configured to start receiving the
scheduling-information-notification system information
(MIB/SIB1) at the current modification period MP(n) without
waiting until the next modification period MP (n+1) starts', when
the mobile station UE is in an idle state or a communicating
state, and when the emergency information receiver unit 21
detects a predetermined indicator (ETWS/PWS indicator) as the
predetermined trigger via a PDCCH (Physical Downlink Control
Channel) including a P-RNTI (Paging-RNTI) as shown in Fig. 6.
[0036]
For example, the predetermined indicator (ETWS/PWS
indicator) is a 1-bit indicator used for notification of the
presence or absence of emergency information, or is primary
notification (which is short information to be notified of first
as to the emergency information and is used to ring mobile
stations).
[0037]
In other words, the emergency information transmitter
unit 12 of the radio base station eNB may be configured to
transmit, as the predetermined trigger, the predetermined

indicator (ETWS/PWS indicator) via the PDCCH (Physical Downlink
Control Channel) including the P-RNTI (Paging-RNTI), to mobile
stations UE in an idle state or a radio-link established state
(RRC_connected state).
[0038]
Additionally, the emergency information receiver unit 21
may also be configured to start receiving the
scheduling-information-notification system information
(MIB/SIB1) at the current modification period MP(n) without
waiting until the next modification period MP (n+1) starts, when
the mobile station UE is in a radio-link established state
(RRC_connected state) or an idle state, and when the emergency
information receiver unit 21 detects a predetermined indicator
(ETWS/PWS indicator) as the predetermined trigger via a PDCCH
(Physical Downlink Control Channel) including an SC-RNTI
(System Change-RNTI, i.e., predetermined identifier) as shown
in Fig. 7.
[0039]
For example, the predetermined indicator (ETWS/PWS
indicator) is a 1-bit indicator used for notification of the
presence or absence of emergency information, or is primary
notification (which is short information to be notified of first
as to the emergency information and is used to ring mobile
stations or the like).
[0040]
In other words, the emergency information transmitter
unit 12 of the radio base station eNB may be configured to
transmit, as the predetermined trigger, the predetermined
indicator (ETWS/PWS indicator) via the PDCCH (Physical Downlink

Control Channel) including the SC-RNTI (System Change-RNTI,
i.e., predetermined identifier), to mobile stations UE in an
idle state or a radio-link established state (RRC connected
state) .
[0041]
In addition, the emergency information receiver unit 21
may also be configured to start receiving the
scheduling-information-notification system information
(MIB/SIB1) at the current modification period MP(n) without
waiting until the next modification periodMP (n+1) starts, when
detecting a PDCCH (Physical Downlink Control Channel) including
an ETWS/PWS-RNTI (predetermined identifier) as the
predetermined trigger as shown in Fig. 8.
[0042]
In other words, the emergency information transmitter
unit 12 of the radio base station eNB may be configured to
transmit, as the predetermined trigger, predetermined
information via the PDCCH (Physical Downlink Control Channel)
including the ETWS/PWS-RNTI (predetermined identifier).
[0043]
The processor unit 22 is configured to perform processing
corresponding to the emergency information notified by the
received emergency-information-notification system
information (e.g., SIB9).
[0044]
For example, as the processing corresponding to the
emergency information, the processor unit 22 may output an alarm
corresponding to the emergency information, or show textual
information or image information corresponding to the emergency

information, on a display.
[0045]
(Operation of Mobile Communication System according to First
Embodiment of Present Invention)
With reference to Fig. 9, operation of the mobile station
according the first embodiment of the present invention will
be described.
[0046]
As shown in Fig. 9, in Step S101, the mobile station UE
detects a PDCCH including an ETWS/PWS-RNTI, or an ETWS/PWS
indicator.
[0047]
In Step S102, the mobile station UE starts receiving the
MIB/SIB9 at the current modification period MP(n) without
waiting until the next modification period MP(n+l) starts.
[0048]
In Step S103, the mobile station UE receives the SIB9 on
the basis of scheduling information notified by the received
MIB/SIB1,and then performs processing (e.g., using an alarm,
display, or the like) corresponding to emergency information
notified by the SIB9.
[0049]
(Advantageous Effect of Mobile Communication System according
to First Embodiment of Present Invention)
With the mobile communication system according to the
first embodiment of the present invention, when detecting a
predetermined trigger, a mobile station UE starts receiving the
MIB/SIB1 at the current modification period MP(n) without
waiting until the next modification period MP (n+1) starts, and

then receives the SIB9 for notification of emergency
information, on the basis of the MIB/SIB1. Accordingly,
multiple mobile stations UE can be notified of generated
emergency information as quickly as possible.
[0050]
(Modification)
With reference to Figs. 10 to 12, the mobile communication
system according to Modification 1 of the present invention will
be described while attention is focused on the difference from
the mobile communication system according to the first
embodiment described above.
[0051]
As shown in Fig. 10, in the mobile communication system
according to Modification 1, the radio base station eNB is
configured to transmit emergency information to multiple mobile
stations UE via a common traffic channel CTCH.
[0052]
The emergency information transmitter unit 12 of the
radio base station eNB according to Modification 1 is configured
to transmit emergency information to the multiple mobile
stations UE via the common traffic channel CTCH.
[0053]
Specifically, the emergency information transmitter unit
12 is configured to notify the multiple mobile stations UE of
a predetermined indicator (ETWS/PWS indicator) , and to transmit
the emergency information to the multiple mobile stations UE
via a downlink resource (the CTCH on a PDSCH (Physical Downlink
Shared Channel)) specified by a physical downlink control
channel (PDCCH) including a predetermined identifier

(ETWS/PWS-RNTI), when the emergency information receiver unit
11 receives emergency information, in other words, when the
emergency information receiver unit 11 detects occurrence of
emergency information.
[0054]
In addition, the emergency information receiver unit 21
of the mobile station UE according to Modification 1 is
configured to receive the emergency information transmitted by
the radio base station eNB via the common traffic channel CTCH.
[0055]
Specifically, the emergency information receiver unit 21
is configured to start monitoring the physical downlink control
channel (PDCCH) including the predetermined indicator
(ETWS/PWS-RNTI), when detecting the predetermined indicator
(ETWS/PWS indicator) . The emergency information receiver unit
21 is configured to receive the emergency information via the
downlink resource (the CTCH on the PDSCH) specified by the
physical downlink control channel (PDCCH), when detecting the
physical downlink control channel (PDCCH).
[0056]
Here, the emergency information receiver unit'21 may be
configured to start monitoring the physical downlink control
channel (PDCCH) including the predetermined identifier
(ETWS/PWS-RNTI) , when the mobile station UE is in an idle state
or a radio-link established state (RRC_connected state, i.e.,
communicating state), and when the emergency information
receiver unit 21 detects the predetermined indicator (ETWS/PWS
indicator) in a paging message.
[0057]

Specifically, the emergency information receiver unit 21
may be configured to start monitoring the physical downlink
control channel (PDCCH) including the predetermined identifier
(ETWS/PWS-RNTI) , when the mobile station UE is in an idle state
or a radio-link established state (RRC_connected state, i.e.,
communicating state), and when the emergency information
receiver unit 21 receives the predetermined indicator (ETWS/PWS
indicator) via a physical downlink control channel including
a paging identifier, that is, when the emergency information
receiver unit 21 detects the predetermined indicator.
[0058]
As shown in Fig. 6, the emergency information receiver
unit 21 may be configured to start monitoring the physical
downlink control channel (PDCCH) including the predetermined
identifier (ETWS/PWS-RNTI), when receiving the predetermined
indicator (ETWS/PWS indicator) via a PDCCH (predetermined
Physical Downlink Control Channel) including a P-RNTI
(Paging-RNTI) , in other words, when detecting the predetermined
indicator.
[0059]
In addition, the emergency information receiver unit 21
may be configured to start monitoring the physical downlink
control channel (PDCCH) including the-predetermined identifier
(ETWS/PWS-RNTI), when the mobile station UE is in a radio-link
established state (RRC_connected state) or an idle state, and
when the emergency information receiver unit 21 detects the
predetermined indicator (ETWS/PWS indicator) via a PDCCH
(predetermined Physical Downlink Control Channel) including an
SC-RNTI (System Change-RNTI, i.e., predetermined identifier)

as shown in Fig. 7.
[0060]
As shown in Fig. 11, the emergency information is
transmitted via the downlink resource (the CTCH on the PDSCH)
specified by the physical downlink control channel (PDCCH)
including the predetermined identifier (ETWS/PWS-RNTI).
[0061]
With reference to Fig. 12, operation of the mobile station
UE according to Modification 1 will be described.
[0062]
As shown in Fig. 12, in Step S201, the mobile station UE
detects an ETWS/PWS indicator.
[0063]
In Step S202, the mobile station UE starts monitoring a
physical downlink control channel (PDCCH) including an
ETWS/PWS-RNTI.
[0064]
In Step S203, the mobile station UE detects the physical
downlink control channel (PDCCH) including the ETWS/PWS-RNTI.
[0065]
In Step S204, the mobile station UE receives emergency
information via a downlink resource (a CTCH on a PDSCH)
specified by the physical downlink control channel (PDCCH) , and
then performs processing (e.g., using an alarm, display, or the
like) corresponding to the emergency information.
[0066]
In the mobile communication system according to
Modification 1, the mobile station UE is configured to start
monitoring a physical downlink control channel (PDCCH)

including an ETWS/PWS-RNTI, when detecting a predetermined
indicator (ETWS/PWS indicator). When detecting the physical
downlink control channel (PDCCH) including the ETWS/PWS-RNTI,
then the mobile station UE is configured to receive emergency
information via a downlink resource specified by the physical
downlink control channel (PDCCH). Accordingly,. multiple
mobile stations UE can be notified of generated emergency
information as quickly as possible.
Note that the features of Modification 1 described above
can be expressed as follows.
[0067]
The first aspect of Modification 1 is summarized as an
emergency-information notification method in which a radio base
station eNB notify multiple mobile stations UE of emergency
information, the method including the steps of: (A) starting,
at the mobile stations UE, monitoring a physical downlink
control channel including a predetermined identifier, when a
predetermined indicator is detected; (B) receiving, at the
mobile stations UE, the emergency information via a downlink
resource specified by the physical downlink control channel,
when the mobile stations UE detect the physical downlink control
channel; and (C) performing, at the mobile stations UE,
processing corresponding to the received emergency
information.
[0068]
The second aspect of Modification 1 is summarized as a
mobile station UE configured to receive emergency information
transmitted by a radio base station eNB, the mobile station UE
including: an emergency-information receiver unit configured

to start monitoring a physical downlink control channel
including a predetermined identifier when detecting a
predetermined indicator, and to receive the emergency
information via a downlink resource specified by the physical
downlink control channel when detecting the physical downlink
control channel; and a processor unit configured to perform
processing corresponding to the received emergency
information.
[0069]
In the second aspect of Modification 1, the emergency
information receiver unit may be configured to start monitoring
the physical downlink control channel, when the mobile station
UE is in an idle state or a communicating state, and when the
emergency information receiver unit detects the predetermined
indicator in a paging message.
[0070]
In the second aspect of Modification 1, the emergency
information receiver unit may be configured to start monitoring
the physical downlink control channel, when the mobile station
UE is in an idle state or a comifiunieating state, and when the
emergency information receiver unit receives the predetermined
indicator via a physical downlink control channel including a
paging identifier.
[0071]
In the second aspect of Modification 1, the emergency
information receiver unit may be configured to start monitoring
the physical downlink control channel, when receiving the
predetermined indicator via a predetermined physical downlink
control channel.

[0072]
The third aspect of Modification 1 is summarized as a radio
base station eNB configured to transmit emergency information
to multiple mobile stations UE, the radio base station eNB
including: an emergency information transmitter unit
configured to notify the multiple mobile stations UE of a
predetermined indicator, and to transmit the emergency
information to the multiple mobile stations UE via a downlink
resource specified by a physical downlink control channel
including a predetermined identifier, when detecting
occuirrence of the emergency information.
[0073]
In the third aspect of Modification 1, the emergency
information transmitter unit may be configured to transmit the
predetermined indicator included in a paging message, to the
mobile stations UE in an idle state or communicating state.
[0074]
In the third aspect of Modification 1, the emergency
information transmitter unit may be configured to transmit the
predetermined indicator via a physical downlink control channel
including a paging identifier, to the mobile stations UE in an
idle state or communicating state.
[0075]
In the third aspect of Modification 1, the emergency
information transmitter unit may be configured to transmit the
predetermined indicator via a predetermined physical downlink
control channel.
[0076]
Note that operation of the above described mobile station

UE and of the radio base station eNB may be implemented by means
of hardware, a software module executed by a processor, or a
combination of both.
[0077]
The software module may be provided in any type of storage
medium such as an RAM (Random Access Memory) , a flash memory,
a ROM (Read Only Memory) , an EPROM (Erasable Programmable ROM) ,
an EEPROM (Electronically Erasable and Programmable ROM), a
register, a hard disk, a removable disk, or a CD-ROM.
[0078]
The storage medium is connected to the processor so that
the processor can read and write information from and to the
storage medium. Also, the storage medium may be integrated into
the processor. Also, the storage medium and the processor may
be provided in an ASIC. The ASIC may be provided in the mobile
station UE and the radio base station eNB. Also, the storage
medium and the processor may be provided in the mobile station
UE and the radio base station eNB as a discrete component.
[0079]
Hereinabove, the present invention has been described in
detail using the above embodiment; however, it is apparent to
those skilled in the art that the present invention is not
limited to the embodiment described herein. Modifications and
variations of the present invention can be made without
departing from the spirit and scope of the present invention
defined by the description of the scope of claims. Thus, what
is described herein is for illustrative purpose, and has no
intention whatsoever to limit the present invention.

Industrial Applicability
[0080]
As has been described above, with the present invention,
it is possible to provide an emergency-information receiving
method, a mobile station, and a radio base station which allow
a plurality of the mobile stations to receive emergency
information as quickly as possible upon detection of occurence
of the emergency information.

Claims
1. An emergency-information receiving method in which a
plurality of mobile stations receives emergency information in
a mobile communication system in which a radio base station is
configured to transmit a plurality of types of system
information repeatedly within a modification period to the
mobile stations via a broadcast channel, and to notify the
mobile stations of a predetermined trigger via the broadcast
channel regardless of the modification period, the method
comprising the steps of:
(A) starting, at the mobile stations, receiving
scheduling-information-notification system information at a
current modification period without waiting until a next
modification period starts, when detecting the predetermined
trigger; and
(B) receiving, at the mobile stations,
emergency-information-notification system information on the
basis of scheduling information notified by the received
scheduling-information-notification system information.
2. The emergency-information receiving method according to
claim 1, further comprising a step of:
(C) performing, at the mobile stations, processing
corresponding to the emergency information notified by the
received emergency-information-notification system
information.
3. A mobile station configured to receive emergency

information in a mobile communication system in which a radio
base station is configured to transmit a plurality of types of
system information repeatedly within a modification period to
a plurality of mobile stations via a broadcast channel, and to
notify the mobile stations of a predetermined trigger via the
broadcast channel regardless of the modification period, the
mobile station comprising:
a scheduling-information-notification system
information receiver unit configured to start receiving
scheduling-information-notification system information at a
current modification period without waiting until a next
modification period starts, when detecting the predetermined
trigger; and
an emergency-information-notification system
information receiver unit configured to receive
emergency-information-notification system information on the
basis of scheduling information notified by the received
scheduling-information-notification system information.
4. The mobile station according to claim 3, further
comprising:
a processor unit configured to perform processing
corresponding to the emergency information notified by the
received emergency-information-notification system
information.
5. The mobile station according to claim 3, wherein
the emergency-information-notification system
information receiver unit is configured to receive no

scheduling information except the
emergency-information-notification system information.
6. The mobile station according to claim 3, wherein
the scheduling-information-notification system
information receiver unit is configured to start receiving the
scheduling-information-notification system information at the
current modification period without waiting until the next
modification period starts, when the mobile station is in an
idle state or a communicating state, and when the
scheduling-information-notification system information
receiver unit detects a predetermined indicator included in a
paging message as the predetermined trigger.
7. The mobile station according to claim 3, wherein
the scheduling-information-notification system
information receiver unit is configured to start receiving the
scheduling-information-notif ication system information at the
current modification period without waiting, until the next
modification period starts, when the mobile station is in an
idle state or a communicating state, and when the
scheduling-information-notification system information
receiver unit receives a predetermined indicator as the
predetermined trigger via a physical downlink control channel
including a paging identifier.
8. The mobile station according to claim 3, wherein
the scheduling-information-notification system
information receiver is configured to start receiving the

scheduling-information-notification system information at the
current modification period without waiting until the next
modification period starts, when receiving a predetermined
indicator as the predetermined trigger via a physical downlink
control channel.
9. A radio base station configured to transmit emergency
information in a mobile communication system in which the radio
base station is configured to transmit a plurality of types of
system information repeatedly within a modification period to
a plurality of mobile stations via a broadcast channel, and to
notify the mobile stations of a predetermined trigger via the
broadcast channel regardless of the modification period, the
radio base station comprising:
a scheduling-information-notification system
information transmitter unit configured to notify, to the
plurality of mobile stations, a predetermined trigger, and to
start transmitting, to the plurality of mobile stations,
scheduling-information-notification system information for
notifying scheduling information which specifies a downlink
resource for transmitting emergency-information-notification
system information at a current modification period without
waiting until a next modification period starts, when
generation of the emergency information is detected; and
an emergency-information-notification system
information transmitter unit configured to transmit
emergency-information-notification system information by
using the downlink resource specified by the scheduling
information.

10. The radio base station according to claim 9, wherein
the scheduling-information-notification system
information transmitter unit is configured to start
transmitting, as the predetermined trigger, a predetermined
indicator included in a paging message, to the mobile stations
in an idle state or a communicating state.
11. The radio base station according to claim 9, wherein
the scheduling-information-notification system
information transmitter unit is configured to transmit, as the
predetermined trigger, a predetermined indicator via a physical
downlink channel including a paging identifier, to the mobile
stations in an idle state or a communicating state.
12. The radio base station according to claim 9, wherein
the scheduling-information-notification system
information transmitter unit is configured to transmit, as the
predetermined trigger, a predetermined indicator via a physical
downlink control channel including a predetermined identifier.

An emergency-information receiving method according to
the present invention includes: starting, at mobile stations
(UE) , receiving scheduling-information-notification system
information at a current modification period without waiting
until a next modification period starts, when detecting a
predetermined trigger; and receiving, at the mobile stations
(UE), emergency-information-notification system information
on the basis of scheduling information notified by the received
scheduling-information-notification system information.

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=dxfw1unb73AiHfWySjWJtw==&loc=wDBSZCsAt7zoiVrqcFJsRw==

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Patent Number

280029

Indian Patent Application Number

3653/KOLNP/2010

PG Journal Number

06/2017

Publication Date

10-Feb-2017

Grant Date

07-Feb-2017

Date of Filing

01-Oct-2010

Name of Patentee

NTT DOCOMO, INC.

Applicant Address

11-1, NAGATACHO 2-CHOME, CHIYODA-KU,TOKYO 100-6150 JAPAN

Inventors:

#	Inventor's Name	Inventor's Address
1	YAMAGISHI, HIROAKI	C/O INTELLECTUAL PROPERTY DEPARTEMENT, NTT DOCOMO, INC,SANNO PARK TOWER,11-1, NAGATACHO 2-CHOME, CHIYODA-KU,TOKYO 100-6150 JAPAN
2	IWAMURA, MIKIO	C/O INTELLECTUAL PROPERTY DEPARTEMENT, NTT DOCOMO, INC,SANNO PARK TOWER,11-1, NAGATACHO 2-CHOME, CHIYODA-KU,TOKYO 100-6150 JAPAN

PCT International Classification Number

H04W 4/22

PCT International Application Number

PCT/JP2009/058201

PCT International Filing date

2009-04-24

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	2008-116464	2008-04-25	Japan
2	2008-116465	2008-04-25	Japan