Alarm system, alarm device, transfer method, and program

Abstract

To provide an alarm system, an alarm, a transfer method, and a program that reduce a transfer delay time in a multi-hop network while reducing power consumption.SOLUTION: In an alarm system 1000, an up-link communication time slot is assigned to each of a fifth fire alarm 600e, a third fire alarm 600c, and a sixth fire alarm 600f. A first monitoring time slot in which the fifth fire alarm should transmit a monitoring signal, and a second monitoring time slot in which the third fire alarm and the sixth fire alarm should transmit monitoring signals are arranged in front of the up-link communication time slots. The fifth fire alarm monitors reception of the monitoring signal in the second monitoring time slot, and stops reception processing of the communication signal when the reception of the monitoring signal is not detected. The fifth fire alarm transmits the monitoring signal in the first monitoring time slot, then receives the communication signal and transfers the communication signal when the reception of the monitoring signal is detected.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to alarm technology, and in particular to an alarm system, an alarm device, a relay route setting method, and a program that use a multi-hop network. [Background technology]

[0002] A fire alarm issues an alarm when it detects a fire. By equipping such fire alarms with a communication function and forming a multi-hop network with multiple fire alarms, it becomes possible for one fire alarm to issue an alarm when the other fire alarms detect a fire (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-35468 A Summary of the Invention [Problem to be solved by the invention]

[0004] If the fire alarms and relay devices included in a multi-hop network do not know the timing of receiving a signal, they must constantly wait for a signal. Constantly waiting for a signal increases the power consumption of the relay devices and the fire alarms. Furthermore, when a multi-hop network is formed by multiple fire alarms, the delay time of forwarding in the multi-hop network may become long. Therefore, it is necessary to reduce the power consumption while shortening the delay time of forwarding in the multi-hop network.

[0005] The present disclosure has been made in consideration of these circumstances, and has an objective to provide a technique for shortening the transfer delay time in a multi-hop network while reducing power consumption. [Means for solving the problem]

[0006] In order to solve the above problems, an alarm system according to an embodiment of the present disclosure comprises multiple alarm devices that form a multi-hop network spreading out from a relay device. The multiple alarm devices include a first alarm device, a second alarm device, and a third alarm device. The first alarm device is capable of communicating with the relay device over i (i is an integer of 1 or greater) hops, and the second and third alarm devices are connected to the first alarm device and are capable of communicating with the relay device over i+1 hops, and a first communication time slot in which the first alarm device can transmit a communication signal, a second communication time slot in which the second alarm device can transmit a communication signal, and a third communication time slot in which the third alarm device can transmit a communication signal are arranged on the time axis, and before the first communication time slot, the second communication time slot, and the third communication time slot, there are a first monitoring time slot in which the first alarm device that is scheduled to transmit a communication signal in the first communication time slot should transmit a monitoring signal, and a second alarm device that is scheduled to transmit a communication signal in the second communication time slot, or a third alarm device that is scheduled to transmit a communication signal in the third communication time slot. The third alarm device that is scheduled to transmit a signal is aligned with a second monitoring time slot in which to transmit a monitoring signal, the first monitoring time slot is aligned after the second monitoring time slot and the first communication time slot is aligned after the second communication time slot and the third communication time slot, the first alarm device monitors for reception of a monitoring signal in the second monitoring time slot, and if it does not detect reception of a monitoring signal it stops reception processing of the communication signal in the second communication time slot and the third communication time slot, and if it detects reception of a monitoring signal the first alarm device transmits a monitoring signal in the first monitoring time slot, then receives the communication signal in the second communication time slot or the third communication time slot and forwards the communication signal in the first communication time slot.

[0007] Another aspect of the present disclosure is an alarm device. This alarm device is one of multiple alarm devices that make up a multi-hop network spreading out from a relay device, and has a communication section that is capable of communicating with the relay device over i (i is an integer of 1 or greater) hops, and is also capable of communicating with other alarm devices that can communicate with the relay device over i+1 hops, and with further other alarm devices, a first communication time slot in which the alarm device can transmit a communication signal, a second communication time slot in which other alarm devices can transmit a communication signal, and a third communication time slot in which further other alarm devices can transmit communication signals are arranged on the time axis, and before the first communication time slot, the second communication time slot, and the third communication time slot, a first monitoring time slot in which an alarm device that is scheduled to transmit a communication signal in the first communication time slot should transmit a monitoring signal, and a communication section that is capable of communicating with other alarm devices that are scheduled to transmit a communication signal in the second communication time slot or the third communication time slot. the first monitoring timeslot is arranged after the second monitoring timeslot and the first communication timeslot is arranged after the second communication timeslot and the third communication timeslot, and if the monitoring unit does not detect reception of a monitoring signal, it stops reception processing of the communication signal in the second communication timeslot and the third communication timeslot, and if the monitoring unit detects reception of a monitoring signal, it causes the monitoring signal to be transmitted in the first monitoring timeslot, and then causes the communication signal to be received in the second communication timeslot or the third communication timeslot and transfers the communication signal in the first communication timeslot.

[0008] Yet another aspect of the present disclosure is a forwarding method. This method is a forwarding method for an alarm device among multiple alarm devices that make up a multi-hop network spreading out from a relay device, in which the alarm device is capable of communicating with the relay device over i (i is an integer of 1 or greater) hops, and is also capable of communicating with other alarm devices that are capable of communicating with the relay device over i+1 hops, and further other alarm devices, a first communication time slot in which the alarm device can transmit a communication signal, a second communication time slot in which the other alarm devices can transmit a communication signal, and a third communication time slot in which the further other alarm devices can transmit communication signals are arranged on the time axis, and a first monitoring time slot in which an alarm device that is scheduled to transmit a communication signal in the first communication time slot should transmit a monitoring signal, and a second communication time slot in which other alarm devices that are scheduled to transmit a communication signal in the second communication time slot, or the first monitoring time slot is arranged after the second monitoring time slot and the first communication time slot is arranged after the second and third communication timeslots, and if reception of a monitoring signal is not detected, stopping reception processing of the communication signal in the second and third communication timeslots, and if reception of a monitoring signal is detected, transmitting a monitoring signal in the first monitoring time slot, and then receiving a communication signal in the second or third communication timeslot and transferring the communication signal in the first communication timeslot.

[0009] Any combination of the above components, and conversion of the present disclosure into a method, device, system, recording medium, computer program, etc. are also valid aspects of the present disclosure. Effect of the Invention

[0010] According to the present disclosure, it is possible to reduce the transfer delay time in a multi-hop network while reducing power consumption. [Brief description of the drawings]

[0011] [Figure 1] 1 is a diagram showing a configuration of an alarm system according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a diagram showing the configuration of the fire alarm device of FIG. [Diagram 3] 3(a)-(d) are diagrams showing the structure of a superframe used in the alarm system of FIG. [Figure 4] FIG. 2 is a diagram showing an example of time slot allocation in the alarm system of FIG. [Diagram 5] FIG. 2 is a diagram showing an overview of downstream communication in the alarm system of FIG. [Figure 6] 6(a)-(c) are diagrams showing an overview of upstream communication in the alarm system of FIG. [Figure 7] 7(a)-(d) are diagrams showing an overview of upstream communication in the alarm system of FIG. [Figure 8] FIG. 13 is a diagram showing an example of time slot allocation in a comparative alarm system. [Figure 9] FIG. 9 is a diagram showing an outline of upstream communication in the alarm system of FIG. 8. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Before specifically describing the present disclosure, an overview will be provided. This embodiment relates to an alarm system installed in facilities such as an apartment building, a detached house, an office, and a hospital. In the alarm system, a relay device is connected to a management device, and a plurality of fire alarms are connected to the relay device via a multi-hop network. In such a network, the management device corresponds to the upper side, and the fire alarm with the greatest number of hops from the relay device corresponds to the lower side. When a fire alarm detects the occurrence of a fire, it transfers the detection result to the relay device, and the relay device transfers the detection result to the management device. When the management device receives the detection result, it selects one or more fire alarms that will sound, and transmits an instruction to sound to the selected one or more fire alarms as the final destination. The relay device and the fire alarm transfer the instruction to sound to the fire alarm at the final destination, and the fire alarm at the final destination performs the instruction to sound when it receives the instruction to sound.

[0013] Here, when a line for a signal from a relay device to a fire alarm device with the greatest number of hops from the relay device is called a "downlink," a line for a signal from the fire alarm device with the greatest number of hops to the relay device is called an "uplink." In this embodiment, one frame is formed by arranging a plurality of time slots, and one superframe is formed by arranging a plurality of frames. Also, one fire alarm device is assigned to one of the time slots for the downlink (hereinafter referred to as a "downlink communication time slot") and one of the time slots for the uplink (hereinafter referred to as an "uplink communication time slot"). The downlink communication time slot is used for transfer of the downlink, and the uplink communication time slot is used for transfer of the uplink.

[0014] In the downlink, in addition to instructions to sound, a signal (hereinafter referred to as a "synchronization signal") is periodically transferred to establish and maintain synchronization so that relay devices and fire alarms in the multi-hop network can transmit and receive data using time slots. On the other hand, the uplink mainly transfers detection results, so the traffic on the uplink is extremely low. However, fire alarms in the multi-hop network must monitor whether detection results are being transmitted in the uplink communication time slots assigned to other lower-level fire alarms. In particular, as the number of lower-level fire alarms increases, the number of uplink communication time slots that must be monitored increases, and so the power consumption of the fire alarms increases. In the following description, the synchronization signal, detection results, and instructions to sound are sometimes collectively referred to as "communication signals."

[0015] A monitoring time slot is introduced to suppress an increase in the power consumption of the fire alarm. As described above, the frame includes a plurality of downstream communication time slots and a plurality of upstream communication time slots. The frame also includes a monitoring time slot (hereinafter referred to as a "monitoring time slot") for a fire alarm that is scheduled to transmit a communication signal in an assigned upstream communication time slot to transmit a signal (hereinafter referred to as a "monitoring signal"). Each fire alarm waits to receive a monitoring signal in the monitoring time slot. If a fire alarm receives a monitoring signal in the monitoring time slot, the fire alarm waits to receive a communication signal in the upstream communication time slot assigned to it. On the other hand, if a fire alarm does not receive a monitoring signal in the monitoring time slot, the fire alarm does not wait to receive a communication signal in the upstream communication time slot assigned to it.

[0016] By introducing a monitoring time slot, the time slots in which the fire alarm should be on standby are limited, thereby reducing the power consumption of the fire alarm. However, if a frame is composed of only one monitoring time slot, the number of fire alarms to which a communication signal can be transferred in one frame is "1", so the transfer of the communication signal in a multi-hop network spans multiple frames, and it is necessary to reduce the transfer delay time. In this embodiment, multiple monitoring time slots are included in one frame in order to reduce the transfer delay time.

[0017] 1 shows the configuration of an alarm system 1000. The alarm system 1000 includes a first fire alarm 600a through a ninth fire alarm 600i collectively referred to as fire alarms 600, a first relay device 700a through a third relay device 700c collectively referred to as relay devices 700, and a management device 800. The number of fire alarms 600 is not limited to "9", and the number of relay devices 700 is not limited to "3".

[0018] The alarm system 1000 is applied to facilities such as homes, offices, and commercial facilities, and is a system that detects fires and notifies the occurrence of a fire. The multiple fire alarms 600 are, for example, residential fire alarms and are equipped with fire detection sensors. The multiple fire alarms 600 are installed, for example, on the ceiling of the facility, but may also be installed on the wall.

[0019] Here, the first fire alarm 600a to the sixth fire alarm 600f constitute a multi-hop network spreading from the first relay device 700a. For example, a relay route connecting the first relay device 700a, the first fire alarm 600a, and the second fire alarm 600b, and a relay route connecting the first relay device 700a, the fourth fire alarm 600d, the fifth fire alarm 600e, and the third fire alarm 600c are formed. In addition, a relay route connecting the first relay device 700a, the fourth fire alarm 600d, the fifth fire alarm 600e, and the sixth fire alarm 600f, and a relay route connecting the first relay device 700a and the seventh fire alarm 600g are also formed. Such relay routes are determined in each fire alarm 600 and are also shared by the first relay device 700a and the management device 800.

[0020] In these relay routes, the first fire alarm 600a, the fourth fire alarm 600d, and the seventh fire alarm 600g can communicate with the first relay device 700a with a hop count of "1". The second fire alarm 600b and the fifth fire alarm 600e can communicate with the first relay device 700a with a hop count of "2". The third fire alarm 600c and the sixth fire alarm 600f can communicate with the first relay device 700a with a hop count of "3".

[0021] The second relay device 700b, the third relay device 700c, the eighth fire alarm device 600h, and the ninth fire alarm device 600i are configured in the same manner as the first relay device 700a, the first fire alarm device 600a, etc. For example, a multi-hop network originating from the first relay device 700a is installed on the first floor of a facility, a multi-hop network originating from the second relay device 700b is installed on the second floor of the facility, and a multi-hop network originating from the third relay device 700c is installed on the third floor of the facility. Different frequencies are used for the multi-hop network originating from the first relay device 700a, the multi-hop network originating from the second relay device 700b, and the multi-hop network originating from the third relay device 700c. In addition, the first relay device 700a, the second relay device 700b, and the third relay device 700c perform wireless communication or wired communication with each other.

[0022] In this way, the relay device 700 performs wireless or wired communication with the multiple fire alarm devices 600 that make up the multi-hop network, and also performs wireless or wired communication with other relay devices 700. It can also be said that the relay device 700 relays communication between the multiple fire alarm devices 600 included in the multi-hop network. Furthermore, the first relay device 700a is connected to the management device 800 by a cable, and performs wired communication with the management device 800. The first relay device 700a and the management device 800 may perform wireless communication.

[0023] The management device 800 is, for example, a controller of a Home Energy Management System (HEMS) installed in a facility. The management device 800 is capable of communicating with a plurality of devices installed in the facility. The plurality of devices include, for example, air conditioners, lighting devices, water heaters, and the like, each having a communication function. The management device 800 is also capable of communicating with a first relay device 700a installed in the facility. Furthermore, the management device 800 is also capable of communicating with a second relay device 700b, a third relay device 700c, and each fire alarm device 600 via the first relay device 700a.

[0024] FIG. 2 shows the configuration of the fire alarm 600. The fire alarm 600 includes a communication unit 620, a processing unit 622, a control unit 624, a fire detection sensor 630, and a buzzer 632, and the control unit 624 includes a monitoring unit 626. The processing unit 622 and the control unit 624 may be integrated. A known technology may be used for the fire detection sensor 630. For example, the fire detection sensor 630 may be an optical smoke detection sensor, and may detect a fire by detecting smoke during a fire using diffuse reflection of light. For example, the fire detection sensor 630 may be a heat detection sensor, and may detect a fire by detecting heat during a fire. For example, the fire detection sensor 630 may be a carbon monoxide detection sensor, and may detect a fire by detecting the concentration of carbon monoxide generated by combustion during a fire. For example, the fire detection sensor 630 may be an infrared detection sensor, and may detect a fire by detecting infrared rays emitted by combustion during a fire.

[0025] The communication unit 620 performs wireless communication with other fire alarms 600 or relay devices 700. The communication unit 620 may perform wired communication. The processing unit 622 processes signals received by the communication unit 620 and generates signals to be transmitted from the communication unit 620. The control unit 624 controls the operation of the communication unit 620 and the processing unit 622. Details of the processing by the control unit 624 will be described later. The buzzer 632 is capable of sounding a buzzer sound. The fire alarm 600 may not include the buzzer 632 but may include the fire detection sensor 630, that is, may have both a detection function and a communication function. Such a fire alarm 600 can also be said to be a sensor capable of issuing an alarm when a fire is detected.

[0026] Figures 3(a)-(d) show the structure of a superframe 1010 used in the alarm system 1000. As shown in Figure 3(a), a certain period is defined as a superframe 1010. The superframe 1010 is arranged repeatedly. The superframe 1010 is divided into a number of frames 1020. As shown in Figure 3(b), one frame 1020 is divided into a number of time slots 1030. Figure 3(c) shows one time slot 1030. A communication signal or a monitoring signal is transmitted in the time slot 1030. The period of the communication signal or the monitoring signal is shorter than the period of one time slot 1030.

[0027] FIG. 3(d) shows the usage of the multiple time slots 1030 included in the frame 1020 shown in FIG. 3(b). Of the multiple time slots 1030, one or more time slots 1030 at the beginning are used as "downstream communication time slots". The three time slots 1030 following the downstream communication time slots are used as "monitoring time slots". The one or more time slots 1030 following the three monitoring time slots are used as "upstream communication time slots". The one or more time slots 1030 following the upstream communication time slots are used as "spare". The number of downstream communication time slots and the number of upstream communication time slots are the same, and are equal to or greater than the number of fire alarms 600 included in the multi-hop network. The number of monitoring time slots is not limited to "3". There need not be any spares.

[0028] Fig. 4 shows an example of allocation of time slots 1030 in the alarm system 1000, and is shown in the same manner as Fig. 3(d). This shows the allocation of multiple time slots 1030 to the first relay device 700a and the first fire alarm device 600a to the seventh fire alarm device 600g in Fig. 1. "M" in Fig. 4 indicates the first relay device 700a, and "S1" to "S7" indicate the first fire alarm device 600a to the seventh fire alarm device 600g, respectively. "N1", "N2", and "N3" will be described later.

[0029] The first relay device 700a, the first fire alarm device 600a, the fourth fire alarm device 600d, the seventh fire alarm device 600g, the second fire alarm device 600b, the fifth fire alarm device 600e, the third fire alarm device 600c, and the sixth fire alarm device 600f are assigned to the downstream communication time slot in order from the front. As described above, the number of hops from the first fire alarm device 600a, the fourth fire alarm device 600d, and the seventh fire alarm device 600g to the first relay device 700a is "1". The number of hops from the second fire alarm device 600b and the fifth fire alarm device 600e to the first relay device 700a is "2", and the number of hops from the third fire alarm device 600c and the sixth fire alarm device 600f to the first relay device 700a is "3". In other words, the fire alarm 600 with a smaller number of hops to the first relay 700a is assigned a downstream communication time slot earlier.

[0030] The sixth fire alarm 600f, the third fire alarm 600c, the fifth fire alarm 600e, the second fire alarm 600b, the seventh fire alarm 600g, the fourth fire alarm 600d, the first fire alarm 600a, and the first relay 700a are assigned to the upstream communication time slots in order from the front. In other words, the fire alarm 600 with the larger number of hops to the first relay 700a is assigned to the front of the upstream communication time slots.

[0031] When focusing on the fifth fire alarm 600e, in the downstream communication time slot, the fifth fire alarm 600e is assigned to the rear of the fourth fire alarm 600d and in front of the third fire alarm 600c and the sixth fire alarm 600f. In the upstream communication time slot, the fifth fire alarm 600e is assigned to the rear of the third fire alarm 600c and the sixth fire alarm 600f and in front of the fourth fire alarm 600d.

[0032] Monitoring time slots "N1", "N2", and "N3" are arranged in front of the downstream communication time slots. The monitoring time slot "N1" is a time slot 1030 in which the fire alarm 600 one hop away from the first relay 700a should transmit a monitoring signal to be received by the first relay 700a. The fire alarm 600 one hop away from the first relay 700a corresponds to the first fire alarm 600a, the fourth fire alarm 600d, and the seventh fire alarm 600g in FIG. 1.

[0033] The monitoring time slot "N2" is a time slot 1030 in which the fire alarm 600 that is hop number "2" from the first relay 700a should transmit a monitoring signal to be received by the fire alarm 600 that is hop number "1" from the first relay 700a. The fire alarm 600 that is hop number "2" from the first relay 700a corresponds to the second fire alarm 600b and the fifth fire alarm 600e in FIG. 1.

[0034] The monitoring time slot "N3" is a time slot 1030 in which the fire alarm 600 that is hop number "3" from the first relay 700a should transmit a monitoring signal to be received by the fire alarm 600 that is hop number "2" from the first relay 700a. The fire alarm 600 that is hop number "3" from the first relay 700a corresponds to the third fire alarm 600c and the sixth fire alarm 600f in FIG. 1.

[0035] The monitoring time slots are arranged in the order of "N3", "N2", and "N1". That is, the fire alarm 600 with a larger number of hops from the first relay device 700a is assigned with a monitoring time slot on the front side. In FIG. 1, the maximum number of hops from the first relay device 700a is "3", so the number of monitoring time slots is also set to "3". However, if the maximum number of hops from the first relay device 700a is "4", the number of monitoring time slots is also set to "4". Here, the number of monitoring time slots is set according to the number of hops with the relay device 700 in the multi-hop network, but is not limited to this. For example, if the relay device 700 is not battery-driven, the current consumption does not need to be reduced, and it can receive signals at all times, not limited to the time slot 1030. In that case, the monitoring time slot "N1" is unnecessary. In addition, one or more fire alarm devices 600 with the same number of hops are assigned to the same monitoring time slot.

[0036] The allocation of these time slots 1030 is determined by the first relay device 700a or the management device 800. For example, the first relay device 700a or the management device 800 determines the allocation of the time slots 1030 based on information on the relay route. The first relay device 700a or the management device 800 notifies each fire alarm device 600 of the determined allocation of the time slots 1030. Therefore, each fire alarm device 600 also knows the allocation of these time slots 1030. As a result, the fire alarm device 600 knows the time slots 1030 that are to transmit communication signals and that have been allocated to itself. The fire alarm device 600 also knows the time slots 1030 in which it can receive communication signals from adjacent fire alarm devices 600 or relay devices 700 on the relay route.

[0037] In such a situation, the communication unit 620 of the fire alarm 600 may perform an intermittent reception operation to reduce power consumption. In the intermittent reception operation in the communication unit 620, a reception operation is performed during a part of the beginning period of the time slot 1030, and if a signal (a communication signal, a monitoring signal) is not received during that part of the period, the reception operation is stopped during the remaining period of the time slot 1030. On the other hand, if a signal is received during that part of the beginning period of the time slot 1030, the reception operation is continued during the remaining period of the time slot 1030.

[0038] FIG. 5 shows an overview of downstream communication in the alarm system 1000. This shows the downstream communication time slot in FIG. 4. The first relay device 700a periodically transmits a synchronization signal to the multiple fire alarm devices 600 constituting the multi-hop network. The synchronization signal is, for example, a beacon signal. The synchronization signal is, for example, transmitted in the first frame 1020 of the superframe 1010 shown in FIG. 3(a), and is not transmitted in the remaining frames 1020. The first relay device 700a transmits a synchronization signal in the time slot 1030 "M" in the first frame 1020 of the superframe 1010. When the fourth fire alarm device 600d receives the synchronization signal in the time slot 1030 "M", it transfers the synchronization signal in the time slot 1030 "S4". In addition, the fourth fire alarm device 600d transmits a response signal to the first relay device 700a in the time slot 1030 "S4". The response signal is, for example, an Ack (ACKnowledgement). The response signal may be included as part of the synchronization signal.

[0039] The first relay device 700a receives a response signal in the time slot 1030 "S4". When the fifth fire alarm device 600e receives a synchronization signal in the time slot 1030 "S4", it transfers the synchronization signal in the time slot 1030 "S5" and transmits a response signal to the fourth fire alarm device 600d. The fourth fire alarm device 600d receives a response signal in the time slot 1030 "S5". Although omitted in FIG. 5, the fourth fire alarm device 600d transfers the response signal from the fifth fire alarm device 600e to the first relay device 700a in the time slot 1030 "S4" of the next frame. The fourth fire alarm device 600d may transfer the response signal from the fifth fire alarm device 600e to the first relay device 700a in the upstream communication time slot used for upstream communication. Furthermore, the fourth fire alarm device 600d does not have to transfer the response signal from the fifth fire alarm device 600e to the first relay device 700a.

[0040] When the third fire alarm 600c receives a synchronization signal in the time slot 1030 "S5", it transfers the synchronization signal in the time slot 1030 "S3" and transmits a response signal to the fifth fire alarm 600e. When the sixth fire alarm 600f receives a synchronization signal in the time slot 1030 "S5", it transfers the synchronization signal in the time slot 1030 "S6" and transmits a response signal to the fifth fire alarm 600e.

[0041] The fifth fire alarm device 600e receives the response signal in the time slots 1030 "S3" and "S6". Although omitted in Fig. 5, the fifth fire alarm device 600e transfers the response signal from the third fire alarm device 600c and the response signal from the sixth fire alarm device 600f to the fourth fire alarm device 600d in the time slot 1030 "S5" of the next frame. The fourth fire alarm device 600d further transfers the response signal from the fifth fire alarm device 600e to the first relay device 700a in the time slot 1030 "S4" of the next frame. Here, the time slot for upstream communication may be used for transferring the response signal, or the response signal may not be transferred.

[0042] In this way, the synchronization signal is transferred in the frame 1020 in which the first relay 700a transmitted the synchronization signal. Furthermore, each fire alarm 600 that receives the synchronization signal from the first relay 700a establishes and maintains timing synchronization with the first relay 700a based on the synchronization signal. Known technology may be used for timing synchronization, so a description thereof will be omitted here.

[0043] 6(a)-(c) show an overview of upstream communication in the alarm system 1000. These show the monitoring time slot and the upstream communication time slot in FIG. 4. In FIG. 6(a), it is assumed that the fire detection sensor 630 of the sixth fire alarm 600f detects the occurrence of a fire. The processing unit 622 of the sixth fire alarm 600f transmits the detection result to the communication unit 620. The detection result includes identification information of the sixth fire alarm 600f that detected the fire, and also includes information regarding the abnormality. The communication unit 620 of the sixth fire alarm 600f transmits a monitoring signal in the monitoring time slot of the time slot 1030 "N3". The fifth fire alarm 600e receives the monitoring signal in the monitoring time slot of the time slot 1030 "N3".

[0044] Fig. 6(b) shows the process following Fig. 6(a). The fifth fire alarm device 600e, which receives a monitoring signal in the monitoring timeslot of the timeslot 1030 "N3", transmits a monitoring signal in the monitoring timeslot of the timeslot 1030 "N2". The fourth fire alarm device 600d receives a monitoring signal in the monitoring timeslot of the timeslot 1030 "N2".

[0045] Fig. 6(c) shows the process following Fig. 6(b). The fourth fire alarm device 600d, which has received the monitoring signal in the monitoring time slot of the time slot 1030 "N2", transmits the monitoring signal in the monitoring time slot of the time slot 1030 "N1". The first relay device 700a receives the monitoring signal in the monitoring time slot of the time slot 1030 "N1".

[0046] As a result, the monitoring signal is transferred from the sixth fire alarm device 600f, which is the lowest in the multi-hop network, to the first relay device 700a within one frame 1020. On the other hand, if the fire detection sensor 630 of the sixth fire alarm device 600f does not detect the occurrence of a fire, the transfer as shown in Figures 6(a)-(c) is not performed.

[0047] Figures 7(a)-(d) show an overview of upstream communications in the alarm system 1000. Figure 7(a) shows processing following Figure 6(c). The sixth fire alarm device 600f, which transmitted a monitoring signal in the monitoring time slot of the time slot 1030 "N3", transmits a detection result in the time slot 1030 "S6". The fifth fire alarm device 600e receives the detection result in the time slot 1030 "S6". Here, the monitoring unit 626 of the fifth fire alarm device 600e monitors the reception of a monitoring signal in the monitoring time slot "N3", and if it does not detect the reception of a monitoring signal, the fifth fire alarm device 600e stops the reception processing of communication signals in the time slots 1030 "S3" and "S6". On the other hand, when the monitoring section 626 of the fifth fire alarm device 600e detects the reception of a monitoring signal, the fifth fire alarm device 600e receives a communication signal in the time slot 1030 “S3” or “S6”.

[0048] FIG. 7(b) shows the process following FIG. 7(a). The fifth fire alarm device 600e, which receives the detection result in the time slot 1030 "S6", transfers the detection result in the time slot 1030 "S5". The fifth fire alarm device 600e also transmits a response signal to the sixth fire alarm device 600f in the time slot 1030 "S5". The response signal may be included as part of the communication signal. The sixth fire alarm device 600f receives the response signal in the time slot 1030 "S5". The fourth fire alarm device 600d receives the detection result in the time slot 1030 "S5".

[0049] FIG. 7(c) shows the process following FIG. 7(b). The fourth fire alarm device 600d, which has received the detection result in the time slot 1030 "S5", transfers the detection result in the time slot 1030 "S4" and transmits a response signal to the fifth fire alarm device 600e. The fifth fire alarm device 600e receives the response signal in the time slot 1030 "S4". Although omitted in FIG. 7(c), the fifth fire alarm device 600e transfers the response signal from the fourth fire alarm device 600d to the sixth fire alarm device 600f in the time slot 1030 "S5" of the next frame 1020. The sixth fire alarm device 600f performs a receiving process in the time slot 1030 "S5" of the frame 1020 following the transmission of the detection result. Here, the time slot for upstream communication may be used for transferring the response signal, or the response signal may not be transferred. The first relay device 700a receives the detection result in the time slot 1030 “S4”.

[0050] Fig. 7(d) shows the process following Fig. 7(c). The first relay device 700a, which has received the detection result in time slot 1030 "S4", transmits a response signal in time slot 1030 "M". The response signal is transferred by the fourth fire alarm device 600d and the fifth fire alarm device 600e, and is received by the sixth fire alarm device 600f.

[0051] When the first relay device 700a receives the detection result from the fourth fire alarm device 600d, it transmits the detection result to the management device 800. When the management device 800 receives the detection result, it identifies the fire alarm device 600 to be sounded based on the identification information included in the detection result. The correspondence between the identification information and the information of the fire alarm device 600 to be sounded is stored in advance in the management device 800. The management device 800 transmits an instruction to sound the fire alarm to the first relay device 700a, with the identified fire alarm 600 as the final destination. The instruction to sound is also forwarded to the second relay device 700b and the third relay device 700c.

[0052] When the fire alarm 600 identified by the management device 800 is the third fire alarm 600c and the sixth fire alarm 600f, the instruction to sound is received by the third fire alarm 600c and the sixth fire alarm 600f by the same transfer as in FIG. 5. Here, the instruction to sound is transmitted instead of the synchronization signal in FIG. 6. When the second relay device 700b and the third relay device 700c receive the instruction to sound from the management device 800 via the first relay device 700a, they transfer the instruction to sound to the fire alarm 600. When the communication unit 620 of the third fire alarm 600c and the sixth fire alarm 600f receives the instruction to sound, the control unit 624 causes the buzzer 632 to sound. The control unit 624 may cause the light-emitting device to blink.

[0053] When focusing on upstream communication in the fifth fire alarm 600e, the fire alarms 600 that have one more hop than the fifth fire alarm 600e are the third fire alarm 600c and the sixth fire alarm 600f. The communication unit 620 of the fifth fire alarm 600e is capable of communicating with the third fire alarm 600c and the sixth fire alarm 600f.

[0054] The monitoring unit 626 monitors the reception of a monitoring signal in the monitoring time slot "N3" among the monitoring time slots "N3", "N2", and "N1" arranged on the time axis. The monitoring time slot "N3" is a monitoring time slot in which the third fire alarm device 600c or the sixth fire alarm device 600f can transmit a monitoring signal.

[0055] When the monitoring unit 626 does not detect the reception of a monitoring signal, the control unit 624 stops the reception process of the communication signal in the communication time slots "S3" and "S6". On the other hand, when the monitoring unit 626 detects the reception of a monitoring signal, the control unit 624 causes the monitoring signal to be transmitted in the monitoring time slot "N2". The control unit 624 also causes the communication signal to be received in the communication time slot "S3" or "S6". Furthermore, when the control unit 624 actually receives the communication signal, the control unit 624 causes the communication signal to be transferred in the communication time slot "S5". At that time, the control unit 624 also transmits a response signal to the third fire alarm 600c or the sixth fire alarm 600f in the communication time slot "S5".

[0056] The monitoring signals described above may be unmodulated signals, unlike communication signals. In this case, the fire alarm device 600 or relay device 700 that receives the monitoring signal repeats intermittent reception operation multiple times within the monitoring time slot, and confirms that the signal is a long signal (e.g., several tens of ms) from the fire alarm device 600 by determining whether the monitoring signal has been received.

[0057] In the following, in order to explain the effect of multiple monitoring time slots included in one frame, the operation of a comparative alarm system including one monitoring time slot in one frame will be explained. The comparative alarm system is of the same type as in Figures 1 and 2. Here, the fire alarm, relay device, and management device included in the comparative alarm system are also indicated as fire alarm 600, relay device 700, and management device 800. The frame and time slot in the comparative alarm system are also indicated as frame 1020 and time slot 1030.

[0058] An example of time slot allocation in a comparative alarm system is shown in Figure 8. Figure 8 is similar to Figure 4, but only one monitoring time slot is placed between the downstream communication time slots and the upstream communication time slots.

[0059] Figure 9 shows an overview of upstream communications in an alarm system. This shows the monitoring time slots and upstream communication time slots in Figure 8. "Monitor" indicates a monitoring time slot. Again, assume that the fire detection sensor 630 of the sixth fire alarm 600f detects the occurrence of a fire. The sixth fire alarm 600f transmits a monitoring signal in the monitoring time slot of frame 1020 "K", and transmits the detection result in time slot 1030 "S6".

[0060] The fifth fire alarm 600e receives a monitoring signal in the monitoring time slot of the frame 1020 "K" and receives a detection result in the time slot 1030 "S6". That is, the fifth fire alarm 600e monitors the reception of a monitoring signal in the monitoring time slot, and if it does not detect the reception of a monitoring signal, it stops the reception process of the communication signal in the time slots 1030 "S3" and "S6". On the other hand, if the fifth fire alarm 600e detects the reception of a monitoring signal, it receives a communication signal in the time slot 1030 "S3" or "S6". Following this, the fifth fire alarm 600e transmits a monitoring signal in the monitoring time slot of the frame 1020 "K+1" and transfers the detection result in the time slot 1030 "S5". The fifth fire alarm 600e also transmits a response signal to the sixth fire alarm 600f in the time slot 1030 "S5". The response signal may be included as a part of the synchronization signal.

[0061] The sixth fire alarm 600f receives a response signal in time slot 1030 "S5" of frame 1020 "K+1". The fourth fire alarm 600d receives a monitoring signal in the monitoring time slot of frame 1020 "K+1", and receives the detection result in time slot 1030 "S5". The fourth fire alarm 600d transmits a monitoring signal in the monitoring time slot of frame 1020 "K+2", transfers the detection result in time slot 1030 "S4", and transmits a response signal to the fifth fire alarm 600e.

[0062] The fifth fire alarm device 600e receives the response signal in time slot 1030 "S4" of frame 1020 "K+2". Although omitted in Fig. 12, the fifth fire alarm device 600e transmits a monitoring signal in the monitoring time slot of frame 1020 "K+3", and transfers the response signal from the fourth fire alarm device 600d to the sixth fire alarm device 600f in time slot 1030 "S5".

[0063] The first relay device 700a receives a monitoring signal in the monitoring time slot of frame 1020 "K+2", and receives a detection result in time slot 1030 "S4". As before, the first relay device 700a transmits a monitoring signal in the monitoring time slot of frame 1020 "K+3", and transmits a response signal in time slot 1030 "M". The response signal is transferred by the fourth fire alarm device 600d and the fifth fire alarm device 600e, and is received by the sixth fire alarm device 600f.

[0064] When the first relay device 700a receives the detection result from the fourth fire alarm device 600d, it transmits the detection result to the management device 800. When the management device 800 receives the detection result, it identifies the fire alarm 600 to be activated based on the identification information included in the detection result. The correspondence between the identification information and the information of the fire alarm 600 to be activated is stored in advance in the management device 800. The management device 800 transmits an instruction to activate the fire alarm to the first relay device 700a, with the identified fire alarm 600 as the final destination.

[0065] That is, when one monitoring time slot is included in one frame 1020, the detection result is delayed by multiple frames 1020 in order to transfer the detection result. On the other hand, when multiple monitoring time slots are included in one frame 1020 as in this embodiment, the detection result is transferred within one frame 1020.

[0066] The subject of the device, system, or method in the present disclosure includes a computer. The computer executes a program to realize the function of the subject of the device, system, or method in the present disclosure. The computer includes a processor that operates according to a program as a main hardware configuration. The type of the processor does not matter as long as it can realize the function by executing the program. The processor is composed of one or more electronic circuits including a semiconductor integrated circuit (IC) or an LSI (Large Scale Integration). The multiple electronic circuits may be integrated into one chip or may be provided on multiple chips. The multiple chips may be integrated into one device or may be provided on multiple devices. The program is recorded on a non-transitory recording medium such as a computer-readable ROM, an optical disk, or a hard disk drive. The program may be stored in the recording medium in advance, or may be supplied to the recording medium via a wide area communication network including the Internet.

[0067] According to this embodiment, since the frame 1020 of the multi-hop network includes a monitoring time slot, if a monitoring signal is not received in the monitoring time slot, the reception process in the upstream communication time slot is stopped, so that the power consumption of the fire alarm 600 and the relay device 700 can be reduced. Furthermore, since the power consumption of the fire alarm 600 and the relay device 700 is reduced, the frequency of battery replacement can be reduced even if the fire alarm 600 and the relay device 700 are battery-powered. Furthermore, since the frequency of battery replacement is reduced, the convenience of the user can be improved. Furthermore, since a plurality of monitoring time slots are included in the frame 1020 of the multi-hop network, transfer from the lowest-level fire alarm 600 to the relay device 700 can be performed within one frame 1020. Furthermore, since transfer from the lowest-level fire alarm 600 to the relay device 700 is performed within one frame 1020, the delay time of transfer can be reduced. Furthermore, since a plurality of monitoring time slots are included in frame 1020 of the multi-hop network, it is possible to reduce the delay time of transfer in the multi-hop network while reducing power consumption.

[0068] Moreover, since a response signal is also transmitted in the communication time slot in which the communication signal should be transferred, the transmission of the response signal can be executed efficiently. Moreover, since the number of monitoring time slots is set according to the maximum number of hops with the relay device 700 in the multi-hop network, it is possible to cause the fire alarm devices 600 with different hop counts to use different monitoring time slots. Moreover, since the fire alarm devices 600 with different hop counts are caused to use different monitoring time slots, it is possible to prevent collision of monitoring signals from the fire alarm devices 600 with different hop counts. Moreover, since one or more fire alarm devices 600 with the same hop count are assigned to the same monitoring time slot, it is possible to suppress an increase in the number of monitoring time slots. Moreover, since the communication signal includes information regarding an abnormality, it is possible to notify the relay device 700 or the management device 800 of the abnormality.

[0069] Furthermore, since multiple time slots 1030 are included in the frame 1020 of the multi-hop network and each time slot 1030 is assigned to a fire alarm 600, the occurrence of signal collisions can be suppressed. Furthermore, since the fire alarm 600 is assigned to the time slots 1030 in an order according to the number of hops from the relay device 700, transfer can be performed efficiently. Furthermore, since the presence or absence of a monitoring signal is determined by repeated intermittent reception multiple times, erroneous determinations due to short-term noise (signals that have the same frequency but are not the desired wave) can be eliminated. Furthermore, since erroneous determinations due to short-term noise are eliminated, even if short-term noise is (erroneously) applied to a monitoring time slot, further transmission of the monitoring signal or reception operation in the upstream communication time slot can be stopped.

[0070] An overview of one aspect of the present disclosure is as follows: An alarm system (1000) of one aspect of the present disclosure comprises multiple alarm devices (600) that form a multi-hop network extending from a relay device (700). The multiple alarm devices (600) include a first alarm device (600), a second alarm device (600), and a third alarm device (600). The first alarm device (600) is capable of communicating with the relay device (700) over i (i is an integer equal to or greater than 1) hop counts, the second alarm device (600) and the third alarm device (600) are connected to the first alarm device (600) and are capable of communicating with the relay device (700) over i+1 hop counts, a first communication time slot in which the first alarm device (600) can transmit a communication signal, a second communication time slot in which the second alarm device (600) can transmit a communication signal, and a third communication time slot in which the third alarm device (600) can transmit a communication signal are arranged on the time axis, and before the first communication time slot, the second communication time slot, and the third communication time slot, there are a first monitoring time slot in which the first alarm device (600) scheduled to transmit a communication signal in the first communication time slot should transmit a monitoring signal, and a second alarm device (600) scheduled to transmit a communication signal in the second communication time slot, and In the third communication time slot, a second monitoring time slot in which a third alarm device (600) that is scheduled to transmit a communication signal should transmit a monitoring signal is aligned, the first monitoring time slot is aligned after the second monitoring time slot, and the first communication time slot is aligned after the second communication time slot and the third communication time slot, the first alarm device (600) monitors reception of a monitoring signal in the second monitoring time slot, and if it does not detect reception of a monitoring signal it stops reception processing of the communication signal in the second communication time slot and the third communication time slot, and if the first alarm device (600) detects reception of a monitoring signal, it transmits a monitoring signal in the first monitoring time slot, then receives a communication signal in the second communication time slot or the third communication time slot and transfers the communication signal in the first communication time slot.

[0071] When the first alarm device (600) receives a communication signal in the second communication time slot or the third communication time slot, it may also transmit a response signal to the second alarm device (600) or the third alarm device (600) in the first communication time slot in which the communication signal should be transferred.

[0072] The number of the multiple monitoring time slots including the first monitoring time slot and the second monitoring time slot may be set according to the maximum number of hops to the relay device (700) in the multi-hop network.

[0073] One or more alarms (600) with the same hop count may be assigned to the same monitoring timeslot.

[0074] The communication signal includes information regarding the abnormality.

[0075] The monitoring signal may be an unmodulated signal. The monitoring signal is an unmodulated signal, and the first alarm device (600) may determine whether or not reception of the monitoring signal has been detected by repeating intermittent reception a number of times in the second monitoring time slot.

[0076] Another aspect of the present disclosure is an alarm device (600). This alarm device (600) is one of multiple alarm devices (600) that make up a multi-hop network spreading out from a relay device (700), and has a communication section (620) that is capable of communicating with the relay device (700) over i (i is an integer of 1 or greater) hops, and is also capable of communicating with other alarm devices (600) that are capable of communicating with the relay device (700) over i+1 hops, and with further other alarm devices (600), a first communication time slot in which the alarm device (600) can transmit a communication signal, and a communication section (620) that is capable of communicating with other alarm devices (600) over i+1 hops. A second communication time slot in which an alarm device (600) can transmit a communication signal, and a third communication time slot in which another alarm device (600) can transmit a communication signal are arranged on the time axis, and before the first communication time slot, second communication time slot, and third communication time slot, there is a first monitoring time slot in which an alarm device (600) that is scheduled to transmit a communication signal in the first communication time slot should transmit a monitoring signal, and a second communication time slot in which an alarm device (600) that is scheduled to transmit a communication signal in the second communication time slot. and a second monitoring time slot in which another alarm device (600) that is to receive a communication signal in the third communication time slot, or a further alarm device (600) that is to transmit a communication signal in the third communication time slot, are lined up, and a monitoring unit (626) that monitors reception of a monitoring signal in the second monitoring time slot; and a control unit (624) in which the first monitoring time slot is lined up after the second monitoring time slot and the first communication time slot is lined up after the second communication time slot and the third communication time slot, and if the monitoring unit (626) does not detect reception of a monitoring signal, it stops reception processing of the communication signal in the second communication time slot and the third communication time slot, and if the monitoring unit (626) detects reception of a monitoring signal, it causes the monitoring signal to be transmitted in the first monitoring time slot, and then causes the communication signal to be received in the second communication time slot or the third communication time slot, and transfers the communication signal in the first communication time slot.

[0077] Yet another aspect of the present disclosure is a transfer method. This method is a forwarding method in an alarm device (600) of multiple alarm devices (600) that make up a multi-hop network spreading out from a relay device (700), in which the alarm device (600) is able to communicate with the relay device (700) over i (i is an integer equal to or greater than 1) hop counts, and is also able to communicate with other alarm devices (600) that are able to communicate with the relay device (700) over i+1 hop counts, and further other alarm devices (600), a first communication time slot in which the alarm device (600) can transmit a communication signal, a second communication time slot in which the other alarm devices (600) can transmit a communication signal, and a third communication time slot in which the further other alarm devices (600) can transmit a communication signal are arranged on the time axis, and a first monitoring time slot in which an alarm device (600) that is scheduled to transmit a communication signal in the first communication time slot should transmit a monitoring signal, and a second communication time slot in which the other alarm devices (600) can transmit a communication signal are arranged before the first communication time slot, the second communication time slot, and the third communication time slot. the first monitoring timeslot is arranged after the second monitoring timeslot and the first communication timeslot is arranged after the second communication timeslot, and the first communication timeslot is arranged after the second communication timeslot and the third communication timeslot, and if reception of a monitoring signal is not detected, reception processing of the communication signal in the second communication timeslot and the third communication timeslot is stopped, and if reception of a monitoring signal is detected, a monitoring signal is transmitted in the first monitoring timeslot, and then a communication signal is received in the second communication timeslot or the third communication timeslot, and the communication signal is transferred in the first communication timeslot.

[0078] The present disclosure has been described above based on the embodiments. These embodiments are merely illustrative, and it will be understood by those skilled in the art that various modifications are possible in the combination of each component or each treatment process, and that such modifications are also within the scope of the present disclosure.

[0079] In this embodiment, the relay device 700 is connected to a fire alarm 600 that has both a fire detection function and an alarm sound generation function. However, the present invention is not limited to this, and the fire alarm 600 may have only a fire detection function. Also, instead of the fire alarm 600, a sensor that detects not only fire but also flood damage, earthquakes, gas leaks, and CO (carbon monoxide) generation due to incomplete combustion may be used. According to this modification, the degree of freedom of the configuration can be improved. [Explanation of symbols]

[0080] 600 fire alarm (alarm), 620 communication section, 622 processing section, 624 control section, 626 monitoring section, 630 fire detection sensor, 632 buzzer, 700 relay device, 800 management device, 1000 alarm system.

Claims

1. Equipped with multiple alarm devices that form a multi-hop network extending from a relay device, the plurality of alarm devices include a first alarm device, a second alarm device, and a third alarm device, the first alarm device is capable of communicating with the relay device over a number of hops of i (i is an integer equal to or greater than 1); the second alarm device and the third alarm device are connected to the first alarm device, and are capable of communicating with the relay device over an i+1 hop count, a first communication time slot in which the first alarm device can transmit a communication signal, a second communication time slot in which the second alarm device can transmit a communication signal, and a third communication time slot in which the third alarm device can transmit a communication signal are arranged on a time axis, a first monitoring time slot in which the first alarm device that is to transmit the communication signal in the first communication time slot should transmit a monitoring signal, and a second monitoring time slot in which the second alarm device that is to transmit the communication signal in the second communication time slot, or the third alarm device that is to transmit the communication signal in the third communication time slot, are arranged before the first communication time slot, the second communication time slot, and the third communication time slot, the first monitoring time slot is arranged behind the second monitoring time slot, and the first communication time slot is arranged behind the second communication time slot and the third communication time slot; the first alarm device monitors reception of the monitoring signal in the second monitoring time slot, and if reception of the monitoring signal is not detected, stops reception processing of the communication signal in the second communication time slot and the third communication time slot; When the first alarm device detects reception of the monitoring signal, it transmits the monitoring signal in the first monitoring time slot, then receives the communication signal in the second communication time slot or the third communication time slot, and transfers the communication signal in the first communication time slot. Alarm system.

2. The alarm system according to claim 1, wherein, when the first alarm device receives the communication signal in the second communication time slot or the third communication time slot, it also transmits a response signal to the second alarm device or the third alarm device in the first communication time slot in which the communication signal should be transferred.

3. 3. The alarm system according to claim 1, wherein the number of monitoring time slots including the first monitoring time slot and the second monitoring time slot is set according to a maximum number of hops to the relay device in the multi-hop network.

4. 4. The alarm system according to claim 3, wherein one or more of the alarm devices having the same hop number are assigned to the same monitoring time slot.

5. 5. The alarm system according to claim 1, wherein the communication signal includes information regarding an abnormality.

6. the supervisory signal is an unmodulated signal, The alarm system according to any one of claims 1 to 5, wherein the first alarm device determines whether or not reception of the monitoring signal has been detected by repeating intermittent reception a number of times in the second monitoring time slot.

7. An alarm device among multiple alarm devices that make up a multi-hop network spreading out from a relay device, a communication unit that is capable of communicating with the relay device over i (i is an integer equal to or greater than 1) hop counts, and is also capable of communicating with other alarm devices that are capable of communicating with the relay device over i+1 hop counts, and with further alarm devices; a first communication time slot in which the alarm device can transmit a communication signal, a second communication time slot in which the other alarm device can transmit a communication signal, and a third communication time slot in which the further other alarm device can transmit a communication signal are arranged on the time axis, and also, arranged before the first communication time slot, the second communication time slot and the third communication time slot are a first monitoring time slot in which the alarm device scheduled to transmit the communication signal in the first communication time slot should transmit a monitoring signal, and a second monitoring time slot in which the other alarm device scheduled to transmit the communication signal in the second communication time slot or the further other alarm device scheduled to transmit the communication signal in the third communication time slot should transmit a monitoring signal; and a monitoring unit that monitors reception of the monitoring signal in the second monitoring time slot. a control unit which, when the monitoring unit does not detect reception of the supervisory signal, stops reception processing of the communication signal in the second communication time slot and the third communication time slot, and, when the monitoring unit detects reception of the supervisory signal, transmits the supervisory signal in the first monitoring time slot, and then receives the communication signal in the second communication time slot or the third communication time slot, and transfers the communication signal in the first communication time slot; An alarm equipped with:

8. A forwarding method in an alarm device among multiple alarm devices that make up a multi-hop network spreading from a relay device, comprising: the alarm device is capable of communicating with the relay device over i (i is an integer equal to or greater than 1) hop counts, and is also capable of communicating with other alarm devices that are capable of communicating with the relay device over i+1 hop counts, and further with other alarm devices; a step of monitoring reception of the monitoring signal in the second monitoring timeslot, in which a first communication timeslot in which the alarm device can transmit a communication signal, a second communication timeslot in which the other alarm device can transmit a communication signal, and a third communication timeslot in which the further other alarm device can transmit a communication signal are arranged on the time axis, and also arranged before the first communication timeslot, the second communication timeslot and the third communication timeslot are a first monitoring timeslot in which the alarm device scheduled to transmit the communication signal in the first communication timeslot should transmit a monitoring signal, and a second monitoring timeslot in which the other alarm device scheduled to transmit the communication signal in the second communication timeslot or the further other alarm device scheduled to transmit the communication signal in the third communication timeslot should transmit a monitoring signal; the first monitoring time slot is arranged behind the second monitoring time slot, and the first communication time slot is arranged behind the second communication time slot and the third communication time slot, when reception of the monitoring signal is not detected, stopping reception processing of the communication signal in the second communication time slot and the third communication time slot, when reception of the monitoring signal is detected, transmitting the monitoring signal in the first monitoring time slot, and then receiving the communication signal in the second communication time slot or the third communication time slot, and transferring the communication signal in the first communication time slot; A transfer method comprising:

9. A program to be executed by an alarm device among a plurality of alarm devices that make up a multi-hop network extending from a relay device, the alarm device is capable of communicating with the relay device over i (i is an integer equal to or greater than 1) hop counts, and is also capable of communicating with other alarm devices that are capable of communicating with the relay device over i+1 hop counts, and further with other alarm devices; a step of monitoring reception of the monitoring signal in the second monitoring timeslot, in which a first communication timeslot in which the alarm device can transmit a communication signal, a second communication timeslot in which the other alarm device can transmit a communication signal, and a third communication timeslot in which the further other alarm device can transmit a communication signal are arranged on the time axis, and also arranged before the first communication timeslot, the second communication timeslot and the third communication timeslot are a first monitoring timeslot in which the alarm device scheduled to transmit the communication signal in the first communication timeslot should transmit a monitoring signal, and a second monitoring timeslot in which the other alarm device scheduled to transmit the communication signal in the second communication timeslot or the further other alarm device scheduled to transmit the communication signal in the third communication timeslot should transmit a monitoring signal; the first monitoring time slot is arranged behind the second monitoring time slot, and the first communication time slot is arranged behind the second communication time slot and the third communication time slot; if reception of the monitoring signal is not detected, stopping reception processing of the communication signal in the second communication time slot and the third communication time slot; if reception of the monitoring signal is detected, transmitting the monitoring signal in the first monitoring time slot, then receiving the communication signal in the second communication time slot or the third communication time slot, and transferring the communication signal in the first communication time slot.

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