Base station device, emergency prompt report notification system, emergency prompt report notification method, and emergency prompt report notification program

Abstract

To provide a base station device, an emergency prompt report notification system, an emergency prompt report notification method, and an emergency prompt report notification program that can preferentially give the notification of information to communication terminals located in areas where there is a high need for emergency information, even outside the coverage area of the base station.SOLUTION: A base station 12 determines transmission order in transmission directions from collection results of location information on a communication terminal 14, and danger location information in emergency information, and transmits the emergency information in each transmission direction by beamforming based on the determined transmission order, thereby transmitting the emergency information to the communication terminal 14 outside a coverage area 16.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a base station device, an emergency news notification system, an emergency news notification method, and an emergency news notification program. [Background technology]

[0002] Patent document 1 describes a technology in which, when a wireless communication terminal located within the coverage area of ​​a wireless base station receives an emergency alert, the wireless communication terminal transmits the emergency alert to a wireless communication terminal located outside the coverage area at a timing different from the timing based on schedule information, using the same channel as the specified channel used by the wireless base station. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-36204 A Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, information is transmitted to a wireless communication terminal located outside a coverage area using D2D (Device to Device), a standard for communication between communication terminals that does not require a base station. However, in D2D, since connection processing is required for communication, there is room for improvement in speeding up information transmission, and it is desirable to give priority to notifying information to communication terminals in areas where emergency information is highly necessary, even outside the coverage area of ​​a base station.

[0005] The present invention has been made in consideration of the above-mentioned facts, and aims to provide a base station device, an emergency alert notification system, an emergency alert notification method, and an emergency alert notification program that are capable of providing priority notification of information to communication terminals located in areas where there is a high need for emergency information, even outside the coverage area of ​​the base station. [Means for solving the problem]

[0006] The base station device of the present invention includes an acquisition unit that acquires location information regarding the location of a communication terminal when the communication terminal that has moved outside the communication range of a base station is present within the communication range of the base station, a receiving unit that receives an emergency information delivery request including danger location information indicating a danger location, and a transmitting unit that transmits the emergency information by beamforming in each transmission direction, which is the direction in which the emergency information is to be transmitted, according to a transmission order of the transmission directions, which is determined based on the location information and the danger location information.

[0007] An emergency news notification system according to the present invention includes the above base station device, and a communication terminal that receives the emergency information transmitted by the transmission unit.

[0008] In addition, the emergency news notification method of the present invention involves a computer acquiring location information regarding the location of a communication terminal when the communication terminal has moved outside the communication range of a base station and is still within the communication range of the base station, and when an emergency information distribution request is received that includes danger location information indicating a danger location, performing a process of transmitting the emergency information by beamforming in each transmission direction, which is the direction in which the emergency information is to be transmitted, according to a transmission order of the transmission directions, which is the direction in which the emergency information is to be transmitted, determined based on the location information and the danger location information.

[0009] In addition, an information processing program according to the present invention causes a computer to acquire location information regarding a location of a communication terminal when the communication terminal that has moved outside the communication range of a base station is present within the communication range of the base station, and when an emergency information distribution request including danger location information indicating a danger location is received, execute a process of transmitting the emergency information by beamforming in each transmission direction, which is the direction in which the emergency information is transmitted, according to a transmission order of the transmission directions, which is determined based on the location information and the danger location information. Effect of the Invention

[0010] According to the present invention, it is possible to provide a base station device, an emergency alert notification system, an emergency alert notification method, and an emergency alert notification program that can provide priority notification of information to communication terminals located in areas where there is a high need for emergency information, even outside the coverage area of ​​the base station. [Brief description of the drawings]

[0011] [Figure 1] 1 is a diagram showing a schematic configuration of an emergency alert notification system according to an embodiment of the present invention; [Diagram 2] 2 is a block diagram showing the configuration of the main parts of a base station and a communication terminal of the emergency alert notification system according to the present embodiment. FIG. [Diagram 3] 2 is a functional block diagram showing the functional configuration of a base station of the emergency warning notification system according to the present embodiment. FIG. [Figure 4] FIG. 13 is a diagram illustrating an example of a transmission direction that is set in advance. [Diagram 5] FIG. 13 is a diagram illustrating an example of a priority table. [Figure 6] FIG. 1 is a diagram illustrating transmission by beamforming, which is a highly directional long-distance transmission signal. [Figure 7] 10 is a flowchart showing an example of a processing flow when a base station of the emergency alert notification system according to the present embodiment collects location information of a communication terminal. [Figure 8] 11 is a flowchart showing an example of the flow of processing performed in a base station when an emergency information distribution request is received from an MME of a higher-level network in the emergency news notification system according to the present embodiment. [Figure 9] 11 is a diagram for explaining an example of a method for determining a transmission order in a transmission direction. FIG. [Figure 10] FIG. 1 is a diagram showing an example of a hazard map and an earthquake epicenter direction. [Figure 11] 13 is a diagram for explaining an example of a method for determining the transmission order of transmission directions when the transmission order of transmission directions is determined further taking into account the degree of risk according to a hazard map. FIG. [Figure 12]11 is a diagram showing an example in which a communication terminal that has received a beamforming signal transfers an emergency alert to a communication terminal in an area outside the coverage area of ​​the base station according to the D2D standard. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, the present embodiment will be described with reference to the drawings. Fig. 1 is a diagram showing a schematic configuration of an emergency alert notification system according to the present embodiment.

[0013] 1, an emergency news notification system 10 according to this embodiment is composed of a base station 12 as an example of a base station device, a communication terminal 14 that was previously present within the communication range (hereinafter referred to as a coverage area 16) in which base station 12 can communicate, and a communication terminal 14 that moved from within coverage area 16 to outside coverage area 16 at some point. Although FIG. 1 shows one communication terminal 14 that moved from within coverage area 16 to outside coverage area 16, there may be multiple communication terminals 14.

[0014] 2 is a block diagram showing the configuration of the main parts of base station 12 and communication terminal 14 of emergency alert notification system 10 according to this embodiment. Since the configuration of the main parts of base station 12 and communication terminal 14 is a general computer configuration, the following description will be given using base station 12 as a representative.

[0015] The base station 12 is composed of a general microcomputer including a CPU (Central Processing Unit) 12A, a ROM (Read Only Memory) 12B, a RAM (Random Access Memory) 12C, a storage 12D, an interface (I / F) 12E, and a bus 12F.

[0016] The CPU 12A is a central processing unit, and controls the overall operation of the device by executing various programs. The ROM 12B stores various control programs such as information processing programs and various parameters in advance. The RAM 12C is used as a work area when the CPU 12A executes various programs. The storage 12D is composed of various storage units such as a hard disk drive (HDD), a solid state drive (SSD), and a flash memory, and stores various data and application programs. The I / F 12E is connectable to communication lines such as various networks, and transmits and receives various data to and from external devices via the communication lines. The above-mentioned units of the server 12 are electrically connected to each other by a bus 12F.

[0017] Next, a description will be given of the functional configuration of the base station 12 of the emergency news notification system 10 according to this embodiment. Fig. 3 is a functional block diagram showing the functional configuration of the base station 12 of the emergency news notification system 10 according to this embodiment.

[0018] The base station 12 has functions of a location information processing unit 20 as an example of an acquisition unit, a transmission direction determination unit 22 as an example of a first generation unit, a memory 24, an emergency information processing unit 26 as an example of a reception unit, an urgency determination unit 28 as an example of a second generation unit and a decision unit, and an RF transmission unit 30 as an example of a transmission unit. Each unit of the base station 12 is realized, for example, by the CPU 12A executing a program stored in the ROM 12B.

[0019] The location information processing unit 20 collects location information obtained by the communication terminal 14 having an attachment history via a Global Navigation Satellite System (GNSS). That is, the location information processing unit 20 obtains location information relating to the location of the communication terminal 14 when the communication terminal 14 that has moved outside the coverage area 16 of the base station 12 is present within the coverage area 16 of the base station 12.

[0020] The transmission direction determination unit 22 presets a transmission direction for transmitting emergency information, associates the transmission direction with the communication terminal 14 based on the position information of the attached communication terminal 14, and stores the associated information in a memory 24 such as the storage 12D as an example of correspondence information. For example, as shown in FIG. 4, eight transmission directions, A to H, are preset. In the example of FIG. 4, eight directions are shown as an example, but the transmission directions are not limited to eight directions and may be less than eight directions or more than eight directions. For example, the transmission direction determination unit 22 associates the communication terminal 14 with a transmission direction whose coordinate value of the position information falls within the range based on a preset range of coordinate values ​​for associating the communication terminal 14 with each transmission direction.

[0021] Information linking the location information of the communication terminal 14 with a preset transmission direction is stored in the memory 24. The information in the memory 24 is discarded after a predetermined period of time, for example, to avoid exceeding capacity.

[0022] The emergency information processor 26 receives an emergency information delivery request as emergency information from an upper network Mobility Management Entity (MME) 18. The emergency information delivery request received as emergency information includes danger location information indicating a danger location such as the epicenter of an earthquake.

[0023] The urgency determination unit 28 determines the priority of each transmission direction based on the danger location information, and generates priority information, which is information on the priority of each transmission direction, as a priority table in the memory 24. The urgency determination unit 28 determines the priority of each transmission direction so that the priority of a transmission direction close to the direction of the epicenter is high, and the priority of a transmission direction far from the direction of the epicenter is low. For example, the urgency determination unit 28 determines the priority of each transmission direction by determining the priority of the transmission direction closest to the direction of the epicenter as 1, the priority of a transmission direction adjacent to the transmission direction with priority 1 as 2, and the priority of a transmission direction adjacent to the transmission direction with priority 2 as 3. In addition, the urgency determination unit 28 determines the transmission order of the transmission directions based on the priority information and the corresponding information, which is information on the communication terminal 14 stored in the memory 24, and updates the priority table in the memory 24. For areas requiring emergency, for example, in the case of an earthquake, the priority can be set so that areas close to the epicenter are given priority for transmission. To achieve this, a priority table is held in the memory 24 of the base station 12, and this allows transmission to be performed in order of communication terminals with higher urgency. For example, an example of a priority table is shown in Fig. 5. In the example of Fig. 5, communication terminals A and D are linked to transmission direction A, communication terminal B is linked to transmission direction B, and communication terminal C is linked to transmission direction C. This example shows an example in which the priority of the transmission directions is determined in the order of transmission directions B, C, and A based on the location information of the emergency information. In this case, since two communication terminals A and D exist in transmission direction A, the example shows an example in which the transmission order is determined in the order of transmission directions B, A, and C.

[0024] The RF transmission unit 30 transmits an ETWS (Earthquake and Tsunami Warning System) signal, which is emergency information, using beamforming in the order of transmission according to the priority table created in the memory 24. The ETWS signal transmits a message called Primary Notification, which notifies the terminal in advance of simple information about what kind of disaster has occurred first. Then, a Secondary Notification, which is detailed information about the event equivalent to a CBS (Cell Broadcast Service), is transmitted. For example, earthquake information includes information about the epicenter and seismic intensity.

[0025] The RF transmitter 30 transmits emergency information by beamforming, which is a highly directional long-distance transmission signal, and as shown in Fig. 6, it is possible to transmit emergency information to communication terminal 14 outside coverage area 16. If communication terminal 14 has not moved significantly from the position held by base station 12, it can receive and detect the beamforming signal and operate the emergency call function based on this signal.

[0026] In addition, assuming that communication terminal 14 may miss a transmission, it is possible to transmit two or more times as shown in Fig. 5. This number of times can be set for each priority of the transmission direction by urgency determination unit 28. For example, the example in Fig. 5 shows an example in which two transmissions are performed for the transmission direction that is first in the transmission order.

[0027] Furthermore, the RF transmitter 30 transmits an ETWS signal as a normal transmission to the communication terminal 14 within the coverage area 16. When normal transmission and transmission using beamforming cannot be performed simultaneously, the RF transmitter 30 performs normal transmission and then performs transmission using beamforming.

[0028] Next, a specific process performed in the base station 12 of the emergency warning notification system 10 according to this embodiment configured as described above will be described.

[0029] First, the process of the base station 12 when collecting location information of the communication terminal 14 will be described. Fig. 7 is a flow chart showing an example of the process flow when the base station of the emergency news notification system 10 according to this embodiment collects location information of the communication terminal 14. The process of Fig. 7 starts, for example, every time a predetermined time has elapsed.

[0030] In step 100, the CPU 12A collects position information of the communication terminal 14 within the coverage area 16, and proceeds to step 102. That is, the position information processing unit 20 collects position information obtained by the communication terminal 14 via GNSS.

[0031] In step 102, the CPU 12A associates the communication terminal 14 with a preset transmission direction based on the collected location information, and proceeds to step 104. That is, the transmission direction determination unit 22 associates the attached communication terminal 14 with a preset transmission direction based on the collected location information.

[0032] In step 104, the CPU 12A judges whether or not information for which a predetermined fixed time has elapsed is present in the memory 24. If the judgment is affirmative, the process proceeds to step 106, and if not, the process proceeds to step 108.

[0033] In step 106, CPU 12A deletes information about communication terminals 14 for which a certain period of time has elapsed, and the process proceeds to step 108. This makes it possible to avoid exceeding the capacity.

[0034] In step 108, the CPU 12A stores the correspondence information, which is information linking the communication terminal 14 with the transmission direction, in the memory 24, and ends the series of processes. That is, the transmission direction determination unit 22 accumulates in the memory 24 the correspondence information linking the previously set transmission direction with the attached communication terminal 14.

[0035] In this way, by base station 12 collecting position information of communication terminal 14 within coverage area 16, it is possible to identify to some extent the direction of communication terminal 14 that has moved outside coverage area 16.

[0036] Next, a process performed by the base station 12 when an emergency information delivery request is received from the MME 18 of the upper network will be described. Fig. 8 is a flowchart showing an example of the flow of processes performed by the base station 12 when an emergency information delivery request is received from the MME 18 of the upper network in the emergency news notification system 10 according to this embodiment. The process in Fig. 8 starts when the MME 18 of the upper network transmits the emergency information delivery request.

[0037] In step 200 , the CPU 12 A receives an emergency information distribution request from the MME 18 and proceeds to step 202 .

[0038] In step 202, the CPU 12A determines the transmission order of the transmission direction and proceeds to step 204. That is, the urgency determination unit 28 determines the transmission order of the transmission direction from the response information, which is the information of the communication terminal 14 stored in the memory 24, and the danger location information in the emergency information, and creates a priority table in the memory 24. The method of determining the transmission order of the transmission direction will be described in detail later. At this time, the information of the communication terminal 14 stored in the memory 24 uses information excluding the information of the communication terminal 14 attached at the start of step 202. This is because there is a high possibility that the attached communication terminal 14 has received the emergency information transmitted by normal transmission.

[0039] In step 204, the CPU 12A transmits the emergency information in the first transmission direction by beamforming, and proceeds to step 206. That is, the RF transmission unit 30 transmits the ETWS signal in the first transmission direction by using beamforming in accordance with the priority table created in the memory 24.

[0040] In step 206, the CPU 12A switches the transmission direction to the next transmission direction with priority, transmits the emergency information by beamforming, and proceeds to step 208. That is, the urgency determination unit 28 switches to the transmission direction with the next transmission priority according to the priority table in the memory 24, and transmits the ETWS signal using beamforming.

[0041] In step 208, the CPU 12A judges whether or not to end the transmission. This judges whether or not the transmission in all transmission directions has been completed according to the priority table. If the judgement is negative, the CPU 12A returns to step 206 and repeats the above-mentioned processing, and if the judgement is positive, the series of processing is terminated.

[0042] In this manner, in this embodiment, even a communication terminal 14 outside the coverage area 16 of the base station 12 can receive emergency information by receiving a highly directional long-distance transmission signal from the base station 12 based on the location information when the communication terminal 14 was within the coverage area 16.

[0043] Furthermore, since beamforming has directivity, by determining the transmission order of the transmission direction and transmitting the information, it is possible to give priority to notifying emergency information to communication terminals 14 that are in areas where there is a high need for the information.

[0044] Next, an example of a method for determining the transmission order of a transmission direction will be described. Fig. 9 is a diagram for explaining an example of a method for determining the transmission order of a transmission direction.

[0045] For example, as shown in FIG. 9, a score for the number of terminals for each transmission direction and a score for the priority set from emergency information are determined in advance, and the transmission order of the transmission directions is set.

[0046] In the example of FIG. 9, the score for the number of terminals is 0 if the number of terminals is 0-1, 1 if the number of terminals is 2-3, and 2 if the number of terminals is 4-5.

[0047] In addition, the points assigned to the priority set from the emergency information are as follows: a direction with a priority of 1 based on the emergency information will receive 4 points, a direction with a priority of 2 will receive 3 points, and a direction with a priority of 3 will receive 2 points.

[0048] Then, the total score of the number of terminals and the points of the priorities set from the emergency information is calculated to determine the transmission order in the transmission direction.

[0049] In the example of Fig. 9, the number of terminals in transmission direction A is 1, so the score based on the number of terminals is 0, and the priority set from the emergency information is 2, so the score based on the priority is 3, and the total score is 3. In addition, the number of terminals in transmission direction B is 2, so the score based on the number of terminals is 1, and the priority set from the emergency information is 1, so the score based on the priority is 4, and the total score is 5. In addition, the number of terminals in transmission direction C is 4, so the score based on the number of terminals is 2, and the priority set from the emergency information is 3, so the score based on the priority is 2, and the total score is 4. Therefore, in the example of Fig. 12, the transmission order of the transmission directions is determined in the order of transmission direction B, transmission direction C, and transmission direction A.

[0050] In the above, an example was described in which the transmission order of the transmission directions was determined from the location information of the communication terminal 14 and the danger location information of the emergency information, but the transmission order may be set further taking into account the hazard map danger level, which is the danger level according to the hazard map. Fig. 10 is a diagram showing an example of a hazard map and an earthquake epicenter direction, and Fig. 11 is a diagram for explaining an example of a method for determining the transmission order of the transmission directions when the transmission order of the transmission directions is determined further taking into account the hazard map danger level.

[0051] For example, a hazard map provided by a city, town, or village is acquired, and the hazard map is divided according to a preset transmission direction and associated with the transmission direction. As shown in FIG. 10, since the hazard map is a map that predicts the degree of danger such as the rate of complete or partial destruction, the degree of danger for each divided transmission direction of the hazard map is taken into consideration. The hazard map danger level for each transmission direction is set such that the danger level of the transmission direction associated with the high-risk area in the hazard map is low, and the danger level of the transmission direction associated with the low-risk area is high. For example, the hazard map danger level is determined by the ratio of areas with a high rate of complete or partial destruction in the divided areas of the hazard map. For example, the hazard map danger level of the corresponding transmission direction is determined to be one of 1 to 5 based on the ratio of areas with a rate of complete or partial destruction of 20% or more in the divided areas of the hazard map. In the following, a case where the southwest direction of the hazard map in FIG. 10 is the epicenter direction will be described as an example.

[0052] For example, as shown in FIG. 11, in addition to the points for the number of terminals in each transmission direction and the points for the priority set from the emergency information, a point for the hazard map risk level is predefined, and the transmission order for the transmission direction is set.

[0053] In the example of FIG. 11, the score for the number of terminals is 0 if the number of terminals is 0-1, 1 if the number of terminals is 2-3, and 2 if the number of terminals is 4-5.

[0054] In addition, the points assigned to hazard map danger levels are as follows: a direction with a hazard map danger level of 1 will receive a score of 4 points, a direction with a danger level of 2 will receive a score of 3 points, a direction with a danger level of 3 will receive a score of 2 points, a direction with a danger level of 4 will receive a score of 1 point, and a direction with a danger level of 5 or above will receive a score of 0 points.

[0055] In addition, the points for the priority set from the emergency information are as follows: a direction with a priority of 1 set from the emergency information will have a score of 5 points, a direction with a priority of 2 will have a score of 4 points, a direction with a priority of 3 will have a score of 3 points, a direction with a priority of 4 will have a score of 2 points, a direction with a priority of 4 will have a score of 2 points, a direction with a priority of 5 will have a score of 1 point, and a direction with a priority of 6 or above will have a score of 0 points.

[0056] Then, the total score of the number of terminals, the hazard up risk level, and the priority level set based on the emergency information is calculated to determine the transmission order in the transmission direction.

[0057] In the example of FIG. 11, the number of terminals in the transmission direction A is 1, so the score based on the number of terminals is 0, the hazard map danger level is 5, so the score is 0, and the priority set from the emergency information is 3, so the score is 3, and the total score is 3. The number of terminals in the transmission direction B is 2, so the score based on the number of terminals is 1, the hazard map danger level is 2, so the score is 3, and the priority set from the emergency information is 1, so the score is 5, and the total score is 9. The number of terminals in the transmission direction C is 4, so the score based on the number of terminals is 2, the hazard map danger level is 3, so the score is 2, and the priority set from the emergency information is 2, so the score is 4, and the total score is 8. The number of terminals in the transmission direction D is 1, so the score based on the number of terminals is 0, the hazard map danger level is 4, so the score is 1, and the priority set from the emergency information is 3, so the score is 3, and the total score is 4. For transmission direction E, the number of terminals is 3, so the score based on the number of terminals is 1, the hazard map risk level is 1, so the score is 4, and the priority set from the emergency information is 4, so the score is 2, for a total score of 7. For transmission direction F, the number of terminals is 2, so the score based on the number of terminals is 1, the hazard map risk level is 5, so the score is 0, and the priority set from the emergency information is 4, so the score is 2, for a total score of 3. Therefore, in the example of Fig. 11, the transmission order of the transmission directions is determined in the order of transmission direction B, transmission direction C, transmission direction E, transmission direction D, transmission direction A, and transmission direction F.

[0058] In this way, by determining the transmission order further taking into consideration the degree of danger based on the hazard map, it is possible to give priority to notifying emergency information to communication terminals 14 that are located in areas where it is predicted that there is a high need for emergency information.

[0059] Note that by using this embodiment in combination with a conventional D2D standard, a communication terminal 14 that receives emergency information by beamforming may forward an ETWS signal transmitted by the base station 12 to a communication terminal 14 that is in an area outside the coverage area 16 of the base station 12. That is, as shown in Fig. 12, a communication terminal 14 that receives a beamforming signal forwards an emergency alert to a communication terminal 14' in an area further outside the coverage area 16 of the base station 12, according to the D2D standard. This makes it possible to forward an emergency alert to a communication terminal 14 in an area that cannot be reached even by beamforming.

[0060] In addition, the processing performed by each unit of the base station 12 in the above embodiment has been described as processing performed by software by executing a program, but it may be processing performed by hardware, or it may be processing that combines both software and hardware.

[0061] Furthermore, the present invention is not limited to the above, and it goes without saying that various modifications can be made without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0062] 10 Emergency Alert Notification System 12 base station 14 Communication terminals 16 Coverage Area 20 Location information processing section 22 Transmission direction determination unit 24 Memory 26 Emergency Information Processing Department 28 Urgency Judgment Department 30 RF transmitter

Claims

1. an acquisition unit that acquires location information relating to a location of a communication terminal when the communication terminal moves outside a communication range of a base station and is present within the communication range of the base station; a receiving unit for receiving an emergency information delivery request including danger location information indicating a danger location; A transmitter that transmits the emergency information in each transmission direction by beamforming according to a transmission order of the transmission directions, which are directions in which the emergency information is to be transmitted, determined based on the location information and the danger location information; A base station device comprising:

2. a first generation unit that generates correspondence information in which the communication terminal is associated with a transmission direction, which is a direction in which the base station transmits emergency information, based on the location information; A second generating unit that determines a priority of each transmission direction based on the danger location information and generates priority information; The base station apparatus according to claim 1 , further comprising: a determination unit that determines a transmission order for the transmission directions based on the correspondence information and the priority information.

3. The base station device according to claim 2 , wherein the determination unit determines the transmission order based on a result of calculating a total score of a score based on the correspondence information and a score based on the priority information for each of the transmission directions.

4. The base station device of claim 2, wherein the determination unit determines the transmission order based on a result of calculating a total score for each transmission direction, the total score based on the corresponding information, the total score based on a previously acquired hazard map, and the total score based on the priority information.

5. The base station device according to claim 1 , wherein the transmission unit further transmits the emergency information to a communication terminal within the communication range.

6. The base station device according to claim 5 , wherein the transmitter performs the beamforming transmission after transmitting the emergency information to a communication terminal within the communication range.

7. A base station device according to any one of claims 1 to 6, a communication terminal that receives the emergency information transmitted by the transmission unit; and Emergency alert notification system including.

8. The emergency alert notification system according to claim 7 , wherein the communication terminal, when receiving the emergency information from the transmission unit, transfers the emergency information to another communication terminal outside the communication range.

9. The computer acquiring location information regarding a location of a communication terminal that has moved outside a communication range of a base station when the communication terminal is present within the communication range of the base station; An emergency alert notification method, when receiving an emergency information distribution request including danger location information indicating a danger location, performing a process of transmitting the emergency information by beamforming in each transmission direction, which is the direction in which the emergency information is to be transmitted, according to a transmission order of the transmission directions, which is determined based on the location information and the danger location information.

10. On the computer, acquiring location information regarding a location of a communication terminal that has moved outside a communication range of a base station when the communication terminal is present within the communication range of the base station; An emergency alert notification program for executing, when an emergency information distribution request including danger location information indicating a danger location, a process of transmitting the emergency information by beamforming in each transmission direction according to a transmission order of the transmission directions, which are the directions in which the emergency information is to be transmitted, determined based on the location information and the danger location information.

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