JP2017212503A - Communication system and communication device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication system and a communication device capable of reducing power consumption as the entire system.SOLUTION: A master unit is configured to perform reception operation in a first waiting period T1 set intermittently. The master unit is configured to receive uplink data Du1 from a slave unit in a first reception period T10 after elapsing a first standby time Tw1 from the reception time point of a first request signal Si1, when the first request signal Si1 from the slave unit was received in the waiting period T1. The slave unit is configured to perform reception operation in a second waiting period T2 set intermittently. The slave unit is configured to receive downlink data from the master unit in a second reception period after elapsing a second standby time from the reception time point of a second request signal, when the second request signal from the master unit was received in the second waiting period T2.SELECTED DRAWING: Figure 3

Description

  The present invention relates generally to a communication system and a communication device, and more specifically, to a communication system including a first communication device and a second communication device capable of bidirectional communication, and as a first communication device or a second communication device. The present invention relates to a communication device.

  Conventionally, in a security system or the like, a communication system having one master unit and a plurality of slave units is used (see, for example, Patent Document 1).

  In the communication system (wireless communication system) described in Patent Document 1, the slave unit uses a primary battery or a secondary battery as a power source, and performs a reception operation intermittently rather than constantly in order to prevent battery consumption as much as possible. Then, when receiving the desired radio wave, the slave unit activates the slave unit receiver again after a predetermined standby time has elapsed. The standby time is set to be equal to or less than the time until the wireless signal is retransmitted from the parent device. Accordingly, since the slave unit reception unit is activated at least at the timing when the radio signal is retransmitted from the master unit, the slave unit reception unit can reliably receive the retransmitted radio signal.

JP2015-119351A

  In the conventional communication system as described above, the power consumption can be reduced by intermittently performing the reception operation for the slave unit. However, since the master unit always operates, the power consumption of the entire system is reduced. It is difficult to plan.

  This invention is made | formed in view of the said reason, and it aims at providing the communication system and communication apparatus which can aim at reduction of the power consumption as the whole system.

  A communication system according to an aspect of the present invention includes a first communication device and a second communication device capable of bidirectional communication. The first communication device is configured to perform a reception operation during a first standby period that is set intermittently. When the first communication device receives the first request signal from the second communication device during the first standby period, the first reception period after the first standby time elapses from the reception time of the first request signal. And receiving uplink data from the second communication device. The second communication device is configured to perform a reception operation during a second standby period that is set intermittently. When the second communication device receives the second request signal from the first communication device during the second standby period, the second reception period after the second standby time elapses from the reception time of the second request signal. And receiving downlink data from the first communication device.

  A communication apparatus according to an aspect of the present invention is used as the first communication apparatus or the second communication apparatus in the communication system.

  According to the present invention, there is an advantage that power consumption of the entire system can be reduced.

FIG. 1 is a block diagram showing a configuration of a communication system according to Embodiment 1 of the present invention. FIG. 2 is a schematic diagram showing the overall configuration of the above communication system. FIG. 3 is a timing chart showing an uplink data transmission operation of the above communication system. FIG. 4 is a timing chart showing the downlink data transmission operation of the above communication system. FIG. 5 is a timing chart showing an uplink data transmission operation of the communication system according to the second embodiment of the present invention. FIG. 6 is a timing chart showing the downlink data transmission operation of the above communication system.

(Embodiment 1)
(1) Overview of Communication System First, an overview of a communication system according to the present embodiment will be described with reference to FIG.

  The communication system 10 according to the present embodiment includes one first communication device (hereinafter also referred to as “parent device”) 1 and a plurality of (four in the example of FIG. 2) second communication devices (hereinafter “ .., 201), 202,.

  The master unit 1 is configured to be capable of bidirectional communication with each of the plurality of slave units 201, 202,. Moreover, the main | base station 1 is comprised so that communication is possible also between the monitoring apparatuses 3 different from the some subunit | mobile_unit 201,202, .... The master unit 1 and the plurality of slave units 201, 202,... Are provided in the building 4. The monitoring device 3 is provided in a place away from the building 4, that is, in a remote place of the building 4. In the following, when the plurality of slave units 201, 202,... Are not particularly distinguished, each of the plurality of slave units 201, 202,. In the present embodiment, the monitoring device 3 is not included in the components of the communication system 10, but the monitoring device 3 may be included in the components of the communication system 10.

  In the following description, a detached house is illustrated as an example of the building 4 to which the communication system 10 is applied. The building 4 to which the communication system 10 is applied is not limited to a detached house, but may be a house other than a detached house such as a dwelling unit of an apartment house, or a non-residential such as an office, a store, or a nursing facility. .

  In short, the parent device 1 has a communication function with each of the child device 2 provided in the same building 4 and the monitoring device 3 provided outside the building 4. In this embodiment, the subunit | mobile_unit 2 has functions, such as a human sensitive sensor, a camera, a fire detector, a temperature / humidity sensor, a window sensor, or a telephone apparatus, for example. Therefore, the parent device 1 can monitor the situation in the building 4 or control the child device 2 by communication with the child device 2, for example. Furthermore, the parent device 1 can transfer, for example, the state of the child device 2 to the monitoring device 3 or remotely control the child device 2 by the monitoring device 3 through communication with the monitoring device 3. As a result, the monitoring device 3 outside the building 4 can also monitor the situation inside the building 4.

  Base unit 1 is a battery-driven type, and is configured to be operable by receiving power supply from battery 15 (see FIG. 1).

  In the present embodiment, a radio communication method using radio waves as a medium is applied to communication between the parent device 1 and the child device 2. As a communication method between the parent device 1 and the child device 2, two types of communication methods of a specific low-power radio of 920 [MHz] band and Wi-Fi (registered trademark) are applied. These two types of communication methods may be used properly depending on the handset 2 or may be used properly depending on the scene with one handset 2.

  Further, as a communication method between the base unit 1 and the monitoring device 3, a carrier network (mobile phone network) 5 such as a 3G (third generation) line or an LTE (Long Term Evolution) line provided by a communication carrier is used. A wireless communication system is applied. That is, in the present embodiment, the base unit 1 is connected to the carrier network 5 and communicates with the monitoring device 3 via the carrier network 5.

  As a basic function, the master unit 1 has a function of transmitting a monitoring signal to the monitoring device 3 when a specific signal is received from the slave unit 2. The “specific signal” here is a specific signal received from the slave unit 2, for example, a notification signal from a human sensor, a fire detector and a window sensor, a video signal from a camera, and a temperature / humidity sensor. It is at least one of a measurement signal and a voice signal from the communication device. The “monitoring signal” is a signal generated by the master unit 1 using a specific signal as a trigger, and may include information included in the specific signal, or may include a fixed message or command corresponding to the specific signal. You may go out. Furthermore, the main | base station 1 has a function which receives operation of a user (resident of the building 4), a function which outputs various information by a display or an audio | voice, etc.

  The plurality of slave units 2 are all battery-driven, and are configured to be operable by receiving power supply from the battery 25 (see FIG. 1).

  The subunit | mobile_unit 2 which has the function of a human sensitive sensor detects the presence or absence of the person in the monitoring area (for example, living rooms, such as a living room) in the building 4, and transmits a notification signal to the main | base station 1 when a person exists. . The subunit | mobile_unit 2 which has a function of a camera images the imaging area in the building 4, and transmits the imaged image | video to the main | base station 1 as a video signal. The subunit | mobile_unit 2 which has a function of a fire detector detects the presence or absence of the occurrence of the fire in the building 4, and transmits a notification signal to the main | base station 1 when a fire occurs. The subunit | mobile_unit 2 which has a function of a temperature / humidity sensor measures the temperature and humidity in the building 4, and transmits a measurement result to the main | base station 1 as a measurement signal. The subunit | mobile_unit 2 which has the function of a window sensor detects opening / closing of the window of the building 4, and transmits a notification signal to the main | base station 1 when a window opens. The handset 2 having the function of a calling device has a speaker and a microphone, and can communicate with the monitoring device 3 via the parent device 1 by transmitting and receiving audio signals to and from the parent device 1. And In addition, the subunit | mobile_unit 2 which has a function of a camera may have a structure which has a microphone and transmits an audio | voice signal to the main | base station 1 with a video signal.

  In the example of FIG. 2, the slave unit 201 has a “human sensor” function, the slave unit 202 has a “camera” function, the slave unit 203 has a “fire detector” function, The machine 204 has a function of a “temperature / humidity sensor”. However, the present invention is not limited to this example, and a plurality of the same type of child devices 2 may be provided, or an air conditioner, a lighting device, or the like may be provided as the child devices 2.

  These slave units 2 have a function of not only unilaterally transmitting signals to the master unit 1 but also receiving signals from the master unit 1. The signal received by the slave unit 2 from the master unit 1 includes, for example, a signal for alive check (survival confirmation) of the slave unit 2, a signal for inquiring the status of the slave unit 2, and a control for controlling the slave unit 2 There are signals and signals for changing the setting of the slave unit 2. The control of the slave unit 2 includes switching of the operation mode of the slave unit 2 such as operation (operation) / stop (standby). That is, the master unit 1 not only collects specific signals from the slave unit 2 but also functions as a controller for controlling the slave unit 2 and the like.

  The monitoring device 3 is provided in a facility owned by a service provider (such as a security company) using the communication system 10, and is connected to the carrier network 5. As a basic function, the monitoring device 3 has a function of outputting information included in the monitoring signal by display or sound when receiving the monitoring signal from the parent device 1. Furthermore, the monitoring device 3 has a function of not only unilaterally receiving signals from the parent device 1 but also transmitting signals to the parent device 1. The signal transmitted from the monitoring device 3 to the parent device 1 includes, for example, a signal for alive check (survival confirmation) of the parent device 1 and the child device 2, a signal for inquiring the state of the child device 2, There are signals for control, signals for changing the settings of the master unit 1 and the slave unit 2, and the like.

  In addition, the monitoring device 3 actually sets a monitoring target group including a plurality of buildings 4 as a monitoring target. In this case, when the parent device 1 provided in the plurality of buildings 4 belonging to the monitoring target group communicates with one monitoring device 3, the monitoring device 3 and the parent device 1 have a one-to-many relationship. However, in the following, for the sake of simplicity of explanation, a case where the monitoring target of the monitoring device 3 is one building 4, that is, a case where the monitoring device 3 and the parent device 1 are in a one-to-one relationship will be described as an example.

(2) Configuration of Communication Device Next, in the communication system 10 according to the present embodiment, a specific configuration of a communication device used as the parent device 1 (first communication device) or the child device 2 (second communication device). A description will be given with reference to FIG. In FIG. 1, only one slave unit 2 among the plurality of slave units 2 is illustrated, but the other slave units 2 have the same configuration.

  As shown in FIG. 1, the communication device (first communication device) used as the base unit 1 includes a first communication unit 11, a first control unit 12, a power supply unit 13, an external communication unit 14, and an input unit. 16 and an output unit 17.

  The 1st communication part 11 is a communication module for communication with the subunit | mobile_unit 2 (2nd communication part 21), Comprising: The 1st control part 12 controls. The first communication unit 11 includes a first transmission unit 111 that transmits a signal to the child device 2 and a first reception unit 112 that receives a signal from the child device 2. In the present embodiment, as described above, since two types of communication methods are applied as the communication method between the parent device 1 and the child device 2, the parent device 1 has 2 types corresponding to the two communication methods. One first communication unit 11 may be provided. One communication method is a specific low-power radio, and the other communication method is Wi-Fi (registered trademark). The specific low-power radio here is a low-power radio that does not require a license. For specific low-power radio, specifications such as the frequency band to be used and the antenna power are specified in each country depending on the application.

  The external communication unit 14 is a communication module for communication with the monitoring device 3 (see FIG. 2), and is controlled by the first control unit 12. The external communication unit 14 includes a transmission unit 141 that transmits a signal to the monitoring device 3 and a reception unit 142 that receives a signal from the monitoring device 3. The transmission unit 141 and the reception unit 142 can operate individually, and the external communication unit 14 can operate only the reception unit 142 without operating the transmission unit 141, for example.

  The power supply unit 13 receives power supply from the battery 15 and generates operating power for the first communication unit 11, the external communication unit 14, the first control unit 12, and the like. The battery 15 is a primary battery stored in the casing of the parent device 1. The battery 15 may be included in the components of the parent device 1 or may not be included in the components of the parent device 1.

  The first control unit 12 controls the first communication unit 11 and the external communication unit 14. In the present embodiment, the first control unit 12 is configured by a microcomputer having a CPU (Central Processing Unit) and a memory as main components. In other words, the first control unit 12 is realized by a computer having a CPU and a memory, and the computer functions as the first control unit 12 when the CPU executes a program stored in the memory. The program is recorded in advance in the memory of the first control unit 12 here, but may be provided through a telecommunication line such as the Internet or recorded in a recording medium such as a memory card.

  Further, the first control unit 12 includes a storage unit 121 and a clock unit 122. The storage unit 121 stores schedule information. The clock unit 122 has a function of measuring the current time (including year, month, day), and is, for example, an RTC (Real-Time Clock). The schedule information is information indicating the timing (date and time) at which a signal is transmitted from the monitoring device 3 to the parent device 1. The schedule information is shared between the monitoring device 3 and the parent device 1.

  The input unit 16 is connected to the operation unit and outputs an input signal corresponding to a user operation on the operation unit to the first control unit 12. The output unit 17 is connected to a display unit, an audio output unit (speaker), and the like, receives an output signal from the first control unit 12, displays various information on the display unit, and outputs audio from the audio output unit. Or When the base unit 1 receives the specific signal from the handset 2 and transmits the monitoring signal to the monitoring device 3, the output unit 17 performs a predetermined display and audio output. Thereby, when the main | base station 1 receives a specific signal from the subunit | mobile_unit 2, not only the monitoring apparatus 3 but the notification in the user in the building 4 is attained. The input unit 16 and the output unit 17 may be connected to an operation unit, a display unit, or the like as a user interface provided in the parent device 1, or a terminal (smart phone, tablet terminal, or the like) different from the parent device 1. And may be connected by communication.

  On the other hand, the communication device (second communication device) used as the slave unit 2 includes a second communication unit 21, a second control unit 22, a power supply unit 23, and a functional module 24 as shown in FIG. doing.

  The 2nd communication part 21, the 2nd control part 22, and the power supply part 23 in the subunit | mobile_unit 2 are the structures corresponding to the 1st communication part 11, the 1st control part 12, and the power supply part 13 in the main | base station 1, respectively. Therefore, in the following, among the configurations of the respective units of the slave unit 2, the description of the configurations similar to the configurations of the respective units of the corresponding master unit 1 will be omitted as appropriate.

  The function module 24 is a module that realizes functions other than communication with the parent device 1 in the child device 2. If it is the subunit | mobile_unit 2 which has a function as sensors, such as a human sensitive sensor, the function module 24 will have a function of a sensor. If it is the subunit | mobile_unit 2 which has a function as a telephone apparatus, the function module 24 will have a function as a telephone apparatus. That is, the slave unit 2 has a configuration in which a communication function with the master unit 1 is added to the function of the functional module 24.

  The second communication unit 21 is a communication module for communication with the parent device 1 (first communication unit 11), and is controlled by the second control unit 22. The second communication unit 21 includes a second transmission unit 211 that transmits a signal to the parent device 1 and a second reception unit 212 that receives a signal from the parent device 1.

  The power supply unit 23 receives power supply from the battery 25 and generates operating power for the second communication unit 21, the functional module 24, the second control unit 22, and the like. The battery 25 is a primary battery stored in the housing of the child device 2. The battery 25 may be contained in the component of the subunit | mobile_unit 2, and does not need to be contained in the component of the subunit | mobile_unit 2. FIG.

  The second control unit 22 is configured by a microcomputer, and controls the second communication unit 21 and the functional module 24. Here, a program for causing the microcomputer to function as the second control unit 22 is recorded in advance in the memory of the second control unit 22, but is recorded through a telecommunication line such as the Internet or a recording medium such as a memory card. May be provided.

  By the way, the main | base station 1 (1st communication part 11) and the subunit | mobile_unit 2 (2nd communication part 21) are comprised so that communication (synchronous communication) of a synchronous system may be performed. Specifically, the base unit 1 transmits a beacon periodically (for example, once every 10 minutes) to a plurality of handset units 2 so that the base unit 1 communicates with the plurality of handset units 2 that have received the beacon. Perform synchronization processing to synchronize. By performing such synchronization processing periodically, the parent device 1 and the child device 2 are synchronized.

(3) Operation Hereinafter, the operation of the communication system 10 according to the present embodiment will be described with reference to FIGS. 3 and 4. Here, communication between one master unit 1 and one slave unit 2 will be described as an example. In FIG. 3 and FIG. 4, “Tx” of “parent device” indicates the operation of the first transmission unit 111 of the parent device 1 (the hatched portion is during transmission operation), and “Rx” of “parent device” is the parent device 1. The operation of the first receiving unit 112 (the shaded area is during the receiving operation). In FIG. 3 and FIG. 4, “Tx” of “child device” indicates the operation of the second transmission unit 211 of the child device 2 (the hatched portion is during transmission operation), and “Rx” of “child device” is the child device. The operation of the second receiving unit 212 of the machine 2 (the shaded area is during the receiving operation) is shown.

(3.1) Standby State In the communication system 10 according to the present embodiment, in the standby state in which neither uplink data nor downlink data is transmitted, as shown in FIG. Operates intermittently. Here, “uplink data” means data transmitted from the slave unit 2 to the master unit 1. “Downlink data” means data transmitted from the parent device 1 to the child device 2. That is, the standby state indicates a state in which neither the parent device 1 nor the child device 2 transmits data in communication between the parent device 1 and the child device 2.

  That is, in the standby state, the base unit 1 performs the reception operation of the first communication unit 11 intermittently during the first standby period T1. Specifically, during a period other than the first standby period T <b> 1 that is set intermittently, the first control unit 12 stops the power supply to the first reception unit 112, thereby first communication unit 11. Stop receiving operation. In the first standby period T1, the first control unit 12 activates the first reception unit 112 to cause the first communication unit 11 to perform a reception operation.

  On the other hand, the handset 2 receives the second communication unit 21 intermittently during the second standby period T2 in the standby state. Specifically, in a period other than the second standby period T <b> 2 that is set intermittently, the second control unit 22 stops the power supply to the second reception unit 212, thereby causing the second communication unit 21 to stop. Stop receiving operation. In the second standby period T2, the second control unit 22 activates the second reception unit 212 to cause the second communication unit 21 to perform a reception operation.

  In the example of FIG. 3, each of the first standby period T1 and the second standby period T2 is set periodically at regular intervals. However, the first standby period T1 and the second standby period T2 may have different time intervals, and each of the first standby period T1 and the second standby period T2 is set irregularly. May be.

(3.2) Uplink Next, an operation at the time of transmission of “uplink data” from the slave unit 2 to the master unit 1 will be described with reference to FIG.

  When transmitting the uplink data Du1 to the master unit 1, the slave unit 2 transmits a first request signal Si1 for activating the first reception unit 112 before transmitting the uplink data Du1. The first request signal Si1 is, for example, dummy data composed of an empty packet having no specific meaning. That is, for example, when a specific event occurs in the child device 2 such as when the child device 2 having a human sensor function detects the presence of a person, it is necessary to transmit the upstream data Du1 to the parent device 1. . In this case, the slave unit 2 transmits the first request signal Si1 in accordance with the timing of the first standby period T1 after the occurrence of a specific event (“Ev” in FIG. 3), and then the upstream data Du1. Send. Here, since the parent device 1 and the child device 2 are synchronized by the periodic synchronization processing as described above, in the child device 2, the transmission timing of the first request signal Si1 is set to the first standby period T1. It is possible to match.

  When the base unit 1 receives the first request signal Si1 from the handset 2 in any of the first standby periods T1 in the standby state described above, the first standby time from the reception point of the first request signal Si1. In the first reception period T10 after Tw1 elapses, the uplink data Du1 is received from the slave unit 2. In the example of FIG. 3, the parent device 1 receives the first request signal Si1 from the child device 2 in the fourth first standby period T1. Here, the first standby time Tw1 is set to be approximately the same as the time interval from when the handset 2 transmits the first request signal Si1 to when the upstream data Du1 is transmitted. That is, the first standby period T1 is a period for waiting for the first request signal Si1, and the uplink data Du1 transmitted from the slave unit 2 to the master unit 1 is transmitted from the slave unit 2 as the uplink data Du1. Received in the first reception period T10 set in accordance with the timing.

  In the present embodiment, base unit 1 determines whether or not first request signal Si1 has been received by performing a radio wave check during first standby period T1. That is, base unit 1 has received first request signal Si1 depending on whether or not the signal reception strength (RSSI: Received Signal Strength Indicator) in first communication unit 11 in the first standby period T1 is greater than or equal to a threshold value. Judge whether or not. If the reception intensity of the signal received by the first communication unit 11 in the first standby period T1 is equal to or greater than the threshold value, the base unit 1 determines that the first request signal Si1 has been received regardless of the content of the signal. On the other hand, if the reception intensity is less than the threshold value, base unit 1 determines that first request signal Si1 has not been received regardless of the content of the signal.

  Then, only when receiving the first request signal Si1, the base unit 1 sets the first reception period T10 to receive the uplink data Du1, and receives the first communication unit 11 during the first reception period T10. Make it work. Specifically, when the base unit 1 receives the first request signal Si1 during the first standby period T1, the power supply to the first receiving unit 112 at the end of the first standby period T1. Is temporarily stopped to stop the reception operation of the first communication unit 11. When the first standby time Tw1 elapses from the end of the first standby period T1 and the first reception period T10 is reached, the base unit 1 activates the first reception unit 112 again to activate the first communication unit 11. Start receiving. On the other hand, when the first request signal Si1 is not received in the first standby period T1, the base unit 1 continues the intermittent reception operation in the first standby period T1. That is, base unit 1 does not activate first receiving unit 112 even when first standby time Tw1 has elapsed from the end of first standby period T1.

  As a result, the base unit 1 receives the first communication unit 11 in accordance with the timing at which the upstream data Du1 is transmitted from the handset 2 while intermittently receiving the first communication unit 11 in the standby state. The upstream communication Du1 can be received by the first communication unit 11.

(3.3) Downlink Data Next, an operation at the time of transmitting “downlink data” from the parent device 1 to the child device 2 will be described with reference to FIG. Here, the operations of the master unit 1 and the slave unit 2 when transmitting the downlink data Dd1 are the same as those of the master unit 1 and the slave unit 2 when transmitting the uplink data Du1. This is the same as the reverse operation.

  That is, when the base unit 1 transmits the downlink data Dd1 to the slave unit 2, the base unit 1 transmits the second request signal Si2 for activating the second reception unit 212 before the transmission of the downlink data Dd1. The second request signal Si2 is, for example, dummy data composed of an empty packet having no specific meaning. For example, when a specific event occurs due to a user's operation on the operation unit or the like in the parent device 1, it is necessary to transmit the downlink data Dd1 to the child device 2. In this case, after the occurrence of a specific event (“Ev” in FIG. 4), base unit 1 transmits second request signal Si2 in accordance with the timing of second standby period T2, and then transmits downlink data Dd1. Send. Here, since the parent device 1 and the child device 2 are synchronized by the periodic synchronization processing as described above, in the parent device 1, the transmission timing of the second request signal Si2 is set to the second standby period T2. It is possible to match.

  When the handset 2 receives the second request signal Si2 from the base unit 1 in any of the second waiting periods T2 in the above-described standby state, the handset 2 receives the second waiting time from the time when the second request signal Si2 is received. In the second reception period T20 after the lapse of Tw2, the downlink data Dd1 is received from the parent device 1. In the example of FIG. 4, the handset 2 receives the second request signal Si2 from the base unit 1 in the fourth second standby period T2. Here, the second standby time Tw2 is set to be approximately the same as the time interval from when the parent device 1 transmits the second request signal Si2 to when the downlink data Dd1 is transmitted. That is, the second standby period T2 is a period for waiting for the second request signal Si2, and the downlink data Dd1 transmitted from the parent device 1 to the child device 2 is transmitted from the parent device 1 as the downlink data Dd1. Is received in the second reception period T20 set in accordance with the timing.

  In this embodiment, the subunit | mobile_unit 2 determines whether the 2nd request signal Si2 was received by performing a radio wave check in the 2nd standby | waiting period T2, similarly to the main | base station 1. FIG. That is, the subunit | mobile_unit 2 judges whether the 2nd request signal Si2 was received by whether the receiving intensity of the signal in the 2nd communication part 21 in 2nd standby | waiting period T2 is more than a threshold value. If the reception intensity of the signal received by the second communication unit 21 in the second standby period T2 is greater than or equal to the threshold value, the handset 2 determines that the second request signal Si2 has been received regardless of the signal content. On the other hand, if the reception intensity is less than the threshold value, handset 2 determines that second request signal Si2 has not been received regardless of the content of the signal.

  And the subunit | mobile_unit 2 sets 2nd receiving period T20 in order to receive downlink data Dd1, and receives the 2nd communication part 21 in 2nd receiving period T20, only when receiving 2nd request signal Si2. Make it work. Specifically, when the handset 2 receives the second request signal Si2 in the second standby period T2, the power supply to the second receiving unit 212 at the end of the second standby period T2 Is temporarily stopped, the reception operation of the second communication unit 21 is temporarily stopped. When the second standby time Tw2 elapses from the end of the second standby period T2 and the second reception period T20 is reached, the slave unit 2 activates the second reception unit 212 again to activate the second communication unit 21. Start receiving. On the other hand, when the second request signal Si2 is not received in the second standby period T2, the slave unit 2 continues the intermittent reception operation in the second standby period T2. That is, the subunit | mobile_unit 2 does not start the 2nd receiving part 212, even if 2nd standby | waiting time Tw2 passes since the end time of 2nd standby | waiting period T2.

  Accordingly, the slave unit 2 receives the second communication unit 21 in accordance with the timing at which the downlink data Dd1 is transmitted from the master unit 1 while the second communication unit 21 is intermittently receiving in the standby state. The second communication unit 21 can receive the downlink data Dd1.

(3.4) Communication Between Base Unit and Monitoring Device Next, communication between the base unit 1 (external communication unit 14) and the monitoring device 3 will be briefly described.

  The first control unit 12 is configured to perform a reception operation at a timing based on the schedule information for the external communication unit 14. That is, during the period until the current time represented by the clock unit 122 matches the date and time represented by the schedule information, the first control unit 12 stops the operation of the receiving unit 142 by stopping the power supply to the receiving unit 142. Let When the current time represented by the clock unit 122 coincides with the date and time represented by the schedule information, the first control unit 12 activates the receiving unit 142 to receive the external communication unit 14 for a predetermined time (for example, 1 minute).

  Accordingly, the first control unit 12 can cause the external communication unit 14 to perform reception operation in accordance with the transmission timing from the monitoring device 3 while intermittently performing the reception operation of the external communication unit 14. The signal can be received by the external communication unit 14.

(4) Effect As described above, the communication system 10 according to the present embodiment includes the parent device 1 (first communication device) and the child device 2 (second communication device) capable of bidirectional communication. The base unit 1 is configured to perform a reception operation during the first standby period T1 set intermittently. When the base unit 1 receives the first request signal Si1 from the handset 2 during the first standby period T1, the base unit 1 enters the first reception period T10 after the first standby time Tw1 has elapsed since the reception of the first request signal Si1. It is configured to receive the upstream data Du1 from the slave unit 2. The subunit | mobile_unit 2 is comprised so that reception operation may be performed in the 2nd standby period T2 set intermittently. When the handset 2 receives the second request signal Si2 from the base unit 1 during the second standby period T2, the handset 2 enters the second reception period T20 after the second standby time Tw2 has elapsed since the reception of the second request signal Si2. It is configured to receive downlink data Dd1 from base unit 1.

  According to this configuration, since base unit 1 performs a reception operation intermittently, power required for reception in the standby state (power consumption of first reception unit 112) is reduced compared to a case in which reception is always performed. be able to. Moreover, the master unit 1 can receive the uplink data Du1 from the slave unit 2 by performing a reception operation in the first reception period T10 in accordance with the timing at which the uplink data Du1 is transmitted from the slave unit 2. Similarly, since the subunit | mobile_unit 2 performs reception operation intermittently, compared with the case where it always performs reception operation, the electric power (power consumption of the 2nd receiving part 212) required for reception in a standby state can be restrained small. . Moreover, the slave unit 2 can receive the downlink data Dd1 from the master unit 1 by performing a reception operation in the second reception period T20 in accordance with the timing at which the downlink data Dd1 is transmitted from the master unit 1. As a result, according to the communication system 10 according to the present embodiment, the power consumption of the entire system can be reduced. Therefore, for example, when both the parent device 1 and the child device 2 are battery-driven, the consumption of the electric energy of the battery related to communication between the parent device 1 and the child device 2 is suppressed, and the operations of the parent device 1 and the child device 2 are performed. The time can be extended. Therefore, for example, when the resident of the building 4 is away for a long period of time due to travel, business trip, evacuation due to a disaster, etc., even when the breaker of the distribution board is cut off, and at the time of power failure of the system power source, The machine 2 can communicate continuously.

  In addition, the communication device according to the present embodiment is used as the parent device 1 (first communication device) or the child device 2 (second communication device) in the communication system 10. According to this configuration, the power consumption of the entire system can be reduced.

  Further, as in the present embodiment, it is preferable that the base unit 1 intermittently performs the receiving operation not only on the first communication unit 11 but also on the external communication unit 14. According to this configuration, in the base unit 1, not only the first communication unit 11 but also the external communication unit 14 operates in a low consumption state. The time can be further extended. In particular, when the external communication unit 14, which consumes more power than the first communication unit 11, operates in a low consumption state, the effect of suppressing the electric energy consumption of the battery 15 is great.

  Further, as in the present embodiment, if both the parent device 1 and the child device 2 are battery-driven, and the communication method between the parent device 1 and the child device 2 is a wireless communication method, the communication system 10 (master unit 1 and slave unit 2) can be constructed wirelessly. If the entire communication system 10 can be constructed wirelessly, the communication system 10 can be easily introduced and removed.

(5) Modified Example The configuration of the first embodiment is merely an example of the present invention, and the present invention is not limited to the first embodiment, and the technical idea according to the present invention is not limited to the first embodiment. As long as it does not deviate from the above, various changes can be made according to the design and the like. Below, the modification of Embodiment 1 is enumerated.

  In the communication system 10, it is not essential that a plurality of slave units 2 serving as communication partners of the master unit 1 are provided, and only one slave unit 2 may be provided. That is, the communication system 10 may be configured by one master unit 1 and one slave unit 2.

  In the first embodiment, the parent device 1 and the child device 2 are composed of communication devices having different configurations. However, the present invention is not limited to this, and the parent device 1 and the child device 2 are communication devices having the same structure. Also good.

  In addition, the fact that the master unit 1 and the plurality of slave units 2 are all battery-driven is not an essential configuration for the communication system 10, and at least a part of the master unit 1 and the plurality of slave units 2 is supplied from an external power source. It may be configured to operate by receiving the power supply. The external power source here is, for example, a system power source (commercial power source) or a distributed power source such as a solar power generation facility. Furthermore, for example, the power supply unit 13 of the base unit 1 is configured to be able to switch between a battery driving mode in which an operating power is generated with the power of the battery 15 and an external power mode in which an operating power is generated with the power of the external power. May be. In this case, the first control unit 12 is preferably configured to switch the control of the first communication unit 11 depending on whether the power supply unit 13 is in the battery drive mode or the external power supply mode. For example, the first control unit 12 intermittently receives the first communication unit 11 only in the battery drive mode in which the operation power is generated by the power of the battery 15, and always operates the first communication unit 11 in the external power supply mode. Start receiving. Similarly, the power supply unit 23 of the child device 2 may be configured to be switchable between the battery drive mode and the external power supply mode.

  In addition, when the base unit 1 receives the first request signal Si1 during the first standby period T1, the first standby time Tw1 elapses after the end of the first standby period T1. It is not essential for the communication system 10 to temporarily stop the reception operation of the communication unit 11. That is, the base unit 1 may continue the reception operation in the first communication unit 11 from the first standby period T1 that has received the first request signal Si1 to the first reception period T10. Similarly, the subunit | mobile_unit 2 may continue reception operation | movement in the 2nd communication part 21 from 2nd standby period T2 which received 2nd request signal Si2 to 2nd reception period T20.

  Further, the determination as to whether or not the first request signal Si1 has been received by the parent device 1 and the determination as to whether or not the second request signal Si2 has been received by the child device 2 are based on the signal reception strength (RSSI). It is not necessarily done. For example, whether or not the first request signal Si1 (or the second request signal Si2) has been received may be determined based on the length of time when the signal is received or the content of the received signal.

  In addition, the provision of the handset 2 in the building 4 is not an essential configuration for the communication system 10, and at least some of the handset 2 may be installed outside the building 4 (outer wall or the like). .

  In addition, the communication method between the parent device 1 and the child device 2 is not limited to the method described above, for example, a specific low-power radio in the 426 [MHz] band, DECT (registered trademark, Digital Enhanced Cordless Telecommunications), Bluetooth (registered trademark). Etc. Furthermore, the communication method between the parent device 1 and the child device 2 is not limited to wireless communication using radio waves as a medium, but may be infrared communication, wired communication, or the like. Similarly, the communication method between the parent device 1 and the monitoring device 3 is not limited to the method described above, and may be, for example, wired communication using a dedicated line, a telephone line for a fixed telephone, or the like. However, in any case, in order to secure communication between the parent device 1 and the child device 2 in battery driving, it is preferable to use a communication path that can be used even during a power failure.

  Further, the battery 15 and the battery 25 are not limited to primary batteries and may be secondary batteries. Further, the battery 15 and the battery 25 may be large-capacity capacitors such as an electric double layer capacitor.

(Embodiment 2)
The communication system 10 according to the present embodiment is implemented in that a time division multiple access (TDMA) system is applied in communication between one master unit 1 and a plurality of slave units 2. This is different from the communication system 10 according to the first embodiment. Hereinafter, the same configurations as those of the first embodiment are denoted by common reference numerals, and description thereof is omitted as appropriate. Regarding the operation, the same points as in the first embodiment will not be described as appropriate.

(6) Operation The operation of the communication system 10 according to the present embodiment will be described with reference to FIGS. Here, communication between one master unit 1 and two slave units 201 and 202 will be described as an example. In FIG. 5 and FIG. 6, “Tx” of “parent device” indicates the operation of the first transmission unit 111 of the parent device 1 (the hatched portion is during transmission operation), and “Rx” of “parent device” is the parent device 1. The operation of the first receiving unit 112 (the shaded area is during the receiving operation). In FIG. 5 and FIG. 6, “Slave unit A” and “Slave unit B” correspond to the slave units 201 and 202, respectively, and “Tx” indicates the operation of the second transmission unit 211 (the hatched portion is during transmission operation). “Rx” indicates the operation of the second receiving unit 212 (the shaded area is during the receiving operation). 5 and 6, “TS” conceptually represents a time slot related to communication between the parent device 1 and the child device 2, and “d” represents the parent device 1 to the child device 2. A time slot for uplink communication to “”, “u” represents a time slot for downlink communication from the handset 2 to the base unit 1. Further, the numbers “0” to “47” in the time slots represent slot numbers assigned to the respective time slots, and “−” represents dummy time slots to which no slot numbers are assigned.

(6.1) Standby State Also in the communication system 10 according to the present embodiment, in a standby state in which neither uplink data nor downlink data is transmitted, as shown in FIG. Both receive intermittently.

  That is, in the standby state, the base unit 1 causes the first communication unit 11 to perform reception operation intermittently during the first standby period T1. On the other hand, in the standby state, the slave unit 2 causes the second communication unit 21 to receive data intermittently during the second standby period T2. In this embodiment, the dummy time slot for uplink communication corresponds to the first standby period T1, and the dummy time slot for downlink communication corresponds to the second standby period T2.

(6.2) Uplink Data Next, an operation at the time of transmitting “uplink data” from the plurality of slave units 2 (201, 202) to the master unit 1 will be described with reference to FIG.

  In the present embodiment, when receiving the upstream data Du1, the master unit 1 receives the first request signal Si1 from the plurality of slave units 2 during the first standby period T1. Then, base unit 1 sets a plurality of time slots TS1 to TS47 corresponding to the plurality of slave units 2 in the first reception period T10, and receives uplink data Du1 from each of the plurality of slave units 2 And received in the corresponding time slots TS1 to TS47. Here, transmission of the upstream data Du1 from the two slave units 201 and 202 to the master unit 1 will be described as an example, but the time slots TS1 to TS47 are set to be compatible with a maximum of 47 slave units 2. . That is, in the first reception period T10, 47 time slots from the time slot TS1 with the slot number “1” to the time slot TS47 with the slot number “47” are set. These 47 time slots TS1 to TS47 correspond to the 47 slave units 2 on a one-to-one basis. The maximum number of slave units 2 that can be handled is not limited to 47, but can be changed as appropriate depending on the number of time slots.

  That is, when the master unit 1 receives the first request signal Si1 from the slave unit 2 in any of the first standby periods T1 in the standby state, the first standby time from the reception point of the first request signal Si1. In the first reception period T10 after Tw1 elapses, the uplink data Du1 is received from the slave unit 2. If the base unit 1 receives the first request signal Si1 from at least one slave unit 2 in the first standby period T1 (dummy time slot for uplink communication), the first reception is performed in the first reception period T10. The unit 112 is activated to cause the first communication unit 11 to perform a receiving operation. Here, when receiving the first request signal Si1, base unit 1 sets a plurality of time slots TS1 to TS47 in the first reception period T10, and performs the first reception in each of the plurality of time slots TS1 to TS47. The unit 112 is activated to cause the first communication unit 11 to perform a receiving operation. Thereby, the main | base station 1 performs reception operation | movement intermittently within 1st reception period T10.

  The subunit | mobile_unit 2 which transmits the uplink data Du1 with respect to the main | base station 1 transmits the 1st request signal Si1 according to the timing of the 1st standby period T1 before transmission of the uplink data Du1. And the subunit | mobile_unit 201 transmits the uplink data Du1 according to the time slot TS1 corresponding to the subunit | mobile_unit 201 within 1st reception period T10. The subunit | mobile_unit 202 transmits the uplink data Du1 according to time slot TS2 corresponding to the subunit | mobile_unit 202 among 1st receiving periods T10. That is, the subunit | mobile_unit 2 transmits the upstream data Du1 when the waiting time according to the corresponding slot number has passed, after progress of 1st waiting time Tw1 from the transmission time of 1st request signal Si1. Thereby, in the main | base station 1, the uplink data Du1 from each of the some subunit | mobile_unit 201,202 can be received by corresponding time slot TS1, TS2. That is, transmission of the uplink data Du1 from the plurality of slave units 2 (201, 202) to the master unit 1 is performed by a time division multiple access (TDMA) system.

  Further, when receiving the first request signal Si1 during the first standby period T1, the main unit 1 receives the first request signal Si1 and before the start of the first reception period T10. Is configured to transmit a synchronization signal Ss1 (beacon) for synchronization. Here, the “synchronization signal” is a signal different from the beacon transmitted from the parent device 1 during the synchronization process performed periodically. Specifically, base unit 1 uses the downlink communication time slot whose slot number is “0” after the first standby period T1 (dummy time slot for uplink communication) for transmission of synchronization signal Ss1. To do. After transmitting the first request signal Si1, the slave unit 2 that transmits the uplink data Du1 to the master unit 1 activates the second reception unit 212 in the downlink communication time slot with the slot number “0”. Then, the second communication unit 21 is operated to receive. Thus, synchronization can be established between the slave unit 2 and the master unit 1 that have received the synchronization signal Ss1, and the synchronization accuracy in the subsequent communication using the time division multiple access (TDMA) system is improved.

  If base unit 1 normally receives upstream data Du1 from at least one slave unit 2, it transmits response signal Sa1 to a plurality of slave units 2. A plurality of response signals Sa1 are transmitted from the base unit 1 in the downlink communication time slot having the slot number “0” in the same procedure as the downlink data transmission described in the column “(6.3) Downlink data”. It is broadcast to the slave unit 2 at the same time. That is, the master unit 1 transmits the response signal Sa1 to the plurality of slave units 2 simultaneously after transmitting the second request signal Si2 during the second standby period T2.

(6.3) Downlink Data Next, an operation at the time of transmission of “downlink data” from the master unit 1 to the plurality of slave units 2 (201, 202) will be described with reference to FIG. Here, at the time of transmission of the downlink data Dd1, a plurality of slave units 2 (201, 202) that have received the downlink data Dd1 transmit a response signal Sa2 (ACK: ACKnowledgement) from the plurality of slave units 2 to the time division multiple. A connection (TDMA) scheme is applied.

  In the present embodiment, when transmitting the downlink data Dd1 to the slave unit 2, the master unit 1 transmits the second request signal Si2 to the plurality of slave units 2 during the second standby period T2, and the second reception period T20. The downlink data Dd1 is transmitted to a plurality of slave units 2. The master unit 1 sets a plurality of time slots TS1 to TS47 corresponding to the plurality of slave units 2 on a one-to-one basis after the end of the second reception period T20, and each of the plurality of slave units 2 that have received the downlink data Dd1 Is received in the corresponding time slots TS1 to TS47.

  That is, when transmitting the downlink data Dd1, the master unit 1 transmits the second request signal Si2 to the plurality of slave units 2 at the same time during the second standby period T2. And the main | base station 1 transmits downlink data Dd1 simultaneously with respect to the several subunit | mobile_unit 2 in 2nd reception period T20. Here, both the second request signal Si2 and the downlink data Dd1 are transmitted from the parent device 1 to the plurality of child devices 2 by multicast (or broadcast). In the present embodiment, the time slot for downlink communication whose slot number is “0” corresponds to the second reception period T20.

  In the standby state, the slave unit 2 receives the second request signal Si2 from the master unit 1 in any second standby period T2, and the second standby time Tw2 has elapsed since the reception of the second request signal Si2. In the subsequent second reception period T20, the downlink data Dd1 from the parent device 1 is received. If the handset 2 receives the second request signal Si2 from the base unit 1 during the second standby period T2 (dummy time slot for downlink communication), the handset 2 will receive the second reception period T20 (downlink with the slot number “0”). In the communication time slot), the second reception unit 212 is activated to cause the second communication unit 21 to perform a reception operation.

  And if the main | base station 1 transmits the downlink data Dd1 in 2nd reception period T20, after that, several time slot TS1-TS47 corresponding to the several subunit | mobile_unit 2 will be set to one to one. Here, transmission of the downlink data Dd1 from the parent device 1 to the two child devices 201 and 202 will be described as an example, but the time slots TS1 to TS47 are set to be compatible with a maximum of 47 child devices 2. . Here, base unit 1 activates first receiving unit 112 in each of a plurality of time slots TS1 to TS47 to cause first communication unit 11 to perform a receiving operation. Thereby, the main | base station 1 performs reception operation | movement intermittently after transmitting downlink data Dd1.

  The subunit | mobile_unit 2 which received the downlink data Dd1 from the main | base station 1 transmits response signal Sa2 with respect to the main | base station 1 after reception of the downlink data Dd1. At this time, the slave unit 201 transmits a response signal Sa2 in accordance with the time slot TS1 corresponding to the slave unit 201. The subunit | mobile_unit 202 transmits response signal Sa2 according to time slot TS2 corresponding to the subunit | mobile_unit 202. FIG. That is, the slave unit 2 transmits the response signal Sa2 when the waiting time corresponding to the corresponding slot number has elapsed after receiving the downlink data Dd1. Thereby, in the main | base station 1, the response signal Sa2 from each of the some subunit | mobile_unit 201,202 can be received by corresponding time slot TS1, TS2. That is, the response signal Sa2 is transmitted from the plurality of slave units 2 (201, 202) to the master unit 1 by the time division multiple access (TDMA) method.

  Further, when the base unit 1 transmits the second request signal Si2 during the second standby period T2, the base unit 1 transmits the second request signal Si2 and transmits the second request signal Si2 until the start of the plurality of time slots TS1 to TS47. A synchronization signal (beacon) for synchronizing with the machine 2 is transmitted. Here, the “synchronization signal” is a signal different from the beacon transmitted from the parent device 1 during the synchronization process performed periodically. In the present embodiment, base unit 1 uses a downlink communication time slot (second reception period T20) having a slot number “0” for transmission of a synchronization signal. That is, the downlink data Dd1 transmitted in the second reception period T20 includes a synchronization signal. As a result, synchronization can be established between the slave unit 2 and the master unit 1 that have received the synchronization signal, and the synchronization accuracy in subsequent communication using the time division multiple access (TDMA) system is improved.

(7) Effect As described above, in the communication system 10 according to the present embodiment, a plurality of slave units 2 (second communication devices) are provided. When receiving the upstream data Du1, the parent device 1 (first communication device) receives the first request signal Si1 from the plurality of child devices 2 during the first standby period T1. Then, base unit 1 sets a plurality of time slots TS1 to TS47 corresponding to the plurality of slave units 2 in the first reception period T10, and receives uplink data Du1 from each of the plurality of slave units 2 , It is configured to receive in the corresponding time slots TS1 to TS47. According to this configuration, the transmission of the uplink data Du1 from the plurality of slave units 2 to the master unit 1 is performed by the time division multiple access (TDMA) method, so the uplink data Du1 from the plurality of slave units 2 Collisions between each other can be avoided. As a result, when the upstream data Du1 is transmitted from the plurality of slave units 2 to the master unit 1 at the same time, the time required to complete the transmission of the upstream data Du1 can be reduced.

  In this case, as in the present embodiment, when the base unit 1 receives the first request signal Si1 during the first standby period T1, the base unit 1 starts the first reception period T10 after receiving the first request signal Si1. In the meantime, it is preferable that the synchronization signal Ss1 is transmitted. The synchronization signal Ss1 here is a signal for synchronizing the master unit 1 and the slave unit 2. According to this configuration, synchronization can be established between the slave unit 2 and the master unit 1 that have received the synchronization signal Ss1, and the synchronization accuracy during transmission of the uplink data Du1 is improved. That is, since resynchronization between the master unit 1 and the slave unit 2 is performed immediately before the first reception period T10, the guard time between the plurality of time slots TS1 to TS47 is relatively shortened, so that the plurality of slave units 2 The time required for transmission of the uplink data Du1 from can be shortened. However, this configuration is not essential for the communication system 10, and the function of the master unit 1 transmitting the synchronization signal Ss1 after the reception of the first request signal Si1 and before the start of the first reception period T10 is omitted. May be.

  Moreover, it is preferable that a plurality of slave units 2 are provided as in the present embodiment. In this case, when transmitting the downlink data Dd1, the master unit 1 transmits the second request signal Si2 to the plurality of slave units 2 in the second standby period T2, and the plurality of slave units in the second reception period T20. 2 is preferably transmitted with downlink data Dd2. And it is preferable that the main | base station 1 sets several time slot TS1-TS47 corresponding to the several subunit | mobile_unit 2 one to one after completion | finish of 2nd reception period T20. The base unit 1 is preferably configured to receive the response signal Sa2 from each of the plurality of handset units 2 that have received the downlink data Dd1 in the corresponding time slots TS1 to TS47. According to this configuration, since the response signal Sa2 is transmitted from the plurality of slave units 2 to the master unit 1 by the time division multiple access (TDMA) method, the response signal Sa2 from the plurality of slave units 2 is transmitted. Collisions between each other can be avoided. As a result, when the downlink data Dd1 is transmitted from the master unit 1 to the plurality of slave units 2 at the same time, it is possible to shorten the time required to complete the reception of the response signal Sa2 from all the slave units 2. .

  In this case, as in the present embodiment, when the base unit 1 transmits the second request signal Si2 during the second standby period T2, the base unit 1 transmits a plurality of time slots TS1 to TS47 after the transmission of the second request signal Si2. It is preferable to be configured to transmit a synchronization signal before the start of. The synchronization signal here is a signal for synchronizing the master unit 1 and the slave unit 2. According to this configuration, synchronization can be established between the slave unit 2 and the master unit 1 that have received the synchronization signal Ss1, and the synchronization accuracy when the response signal Sa2 is transmitted is improved. That is, since resynchronization between the master unit 1 and the slave unit 2 is performed immediately before the plurality of time slots TS1 to TS47, the guard time between the plurality of time slots TS1 to TS47 is relatively shortened, so that The time required for transmitting the response signal Sa2 from the machine 2 can be shortened. However, this configuration is not an essential configuration for the communication system 10, and the function that the master unit 1 transmits the synchronization signal after the transmission of the second request signal Si2 and before the start of the plurality of time slots TS1 to TS47 is performed. It may be omitted.

(8) Modification The configuration of the second embodiment is merely an example of the present invention, and the present invention is not limited to the second embodiment, and the technical idea according to the present invention is not limited to the second embodiment. As long as it does not deviate from the above, various changes can be made according to the design and the like. Below, the modification of Embodiment 2 is enumerated.

  The configuration in which the parent device 1 transmits the synchronization signal Ss1 after the reception of the first request signal Si1 and before the start of the first reception period T10 is the same as that described in the first embodiment. The present invention can also be applied to a configuration in which one-to-one communication is performed. That is, even if the upstream data Du1 is not assumed to be transmitted by the time division multiple access (TDMA) method, the base unit 1 receives the first request signal Si1 and starts the first reception period T10. The configuration in which the synchronization signal Ss1 is transmitted until the time is applicable.

  Further, the communication system 10 transmits only the uplink data Du1 from the plurality of slave units 2 to the master unit 1 and the transmission of the response signal Sa2 from the plurality of slave units 2 to the master unit 1. A time division multiple access (TDMA) scheme may be applied. When the time division multiple access (TDMA) method is applied only to transmission of uplink data Du1 from a plurality of slave units 2 to master unit 1, for example, CSMA / CA (Carrier) is used for transmission of response signal Sa2. Sense Multiple Access / Collision Avoidance) is applied.

  The configuration (including the modification) described in the second embodiment can be applied in appropriate combination with the configuration (including the modification) described in the first embodiment.

1 Master unit (first communication device)
2, 201, 202, 203, 204 Slave unit (second communication device)
10 communication system Dd1 downlink data Du1 uplink data Sa2 response signal Si1 first request signal Si2 second request signal Ss1 synchronization signal T1 first standby period T2 second standby period T10 first reception period T20 second reception period TS1 to TS47 Time slot Tw1 First waiting time Tw2 Second waiting time

Claims (6)

A first communication device and a second communication device capable of bidirectional communication;
The first communication device is
When a reception operation is performed during the first standby period that is set intermittently and the first request signal is received from the second communication device during the first standby period, from the time when the first request signal is received. It is configured to receive uplink data from the second communication device in a first reception period after the first waiting time has elapsed,
The second communication device is
When a reception operation is performed during the second standby period that is set intermittently and the second request signal is received from the first communication device during the second standby period, from the time when the second request signal is received. A communication system configured to receive downlink data from the first communication device in a second reception period after the elapse of a second standby time. A plurality of the second communication devices are provided,
The first communication device is
When receiving the upstream data,
Receiving the first request signal from the plurality of second communication devices in the first standby period;
In the first reception period, a plurality of time slots corresponding to the plurality of second communication devices are set on a one-to-one basis, and uplink data from each of the plurality of second communication devices is received in the corresponding time slots. The communication system according to claim 1, wherein the communication system is configured to. The first communication device is
When the first request signal is received during the first standby period, synchronization with the second communication device is performed after the reception of the first request signal and before the start of the first reception period. The communication system according to claim 1, wherein the communication system is configured to transmit a synchronization signal for the communication. A plurality of the second communication devices are provided,
The first communication device is
When transmitting the downlink data,
Transmitting the second request signal to the plurality of second communication devices in the second standby period;
Transmitting the downlink data to the plurality of second communication devices in the second reception period;
A response signal from each of the plurality of second communication devices that has received the downlink data by setting a plurality of one-to-one time slots corresponding to the plurality of second communication devices after the end of the second reception period. The communication system according to any one of claims 1 to 3, wherein the communication system is configured to receive at a corresponding time slot. The first communication device is
When the second request signal is transmitted during the second standby period, synchronization with the second communication device is performed after the transmission of the second request signal and before the start of the plurality of time slots. The communication system according to claim 4, wherein the communication system is configured to transmit a synchronization signal.   The communication apparatus according to any one of claims 1 to 5, wherein the communication apparatus is used as the first communication apparatus or the second communication apparatus.

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