JP2003298759A - Communication apparatus and its system and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication apparatus that can surely transmit and receive prescribed information within a prescribed period when a prescribed condition is met when transmitting and receiving the information by radio, by using a single channel for which a radio communication period is assigned to each communication apparatus on a time-division basis. <P>SOLUTION: The communication apparatus has a UWB transmitting-receiving section 41 which performs transmission and reception by using the single channel for which a communication frame is assigned to each communication apparatus on a time-division basis, and a microcomputer 44 which specifies an exclusive reception frame assigned to the channel based on a received control slot, and controls the transmitting-receiving section 41 to perform reception or to wait for reception in the other situation than an emergency situation and to notify emergency when the emergency situation occurs. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication device for performing wireless transmission / reception using a channel in which a wireless communication period is allocated to each communication device in a time division manner, a system thereof and a method thereof.

[0002]

2. Description of the Related Art For example, in Japanese Unexamined Patent Publication No. 2001-103581 and Japanese Unexamined Patent Publication No. 2001-245364, various devices in a home are provided with an information transmission function, and the state of the device and the state detected by the device are described. A system for wirelessly transmitting information to another device is disclosed. UWB (Ultra Wide Band) communication, which uses a pulse having a pulse width of 1 ns or less and uses an ultra-wide band over several GH, is known as such a wireless communication means.
Such UWB communication consumes less power during transmission,
Since it can be easily incorporated into various devices such as at home, it is useful for constructing a home network.
In the UWB communication described above, it is practically impossible to set a plurality of channels by frequency multiplexing, and normally, a single channel is assigned to each communication device in frame units for transmission and reception.

[0003]

However, for example, when a communication device transmits emergency information, it may take time until a frame is assigned to the communication device, and the emergency information may not be immediately transmitted. There's a problem.

The present invention has been made in view of the above circumstances, and an object thereof is to meet predetermined conditions when performing wireless transmission / reception using a channel in which a wireless communication period is allocated to each communication device in a time division manner. An object of the present invention is to provide a communication device, a system thereof, and a method thereof that can reliably transmit and receive predetermined information within a predetermined period when satisfied.

[0005]

In order to achieve the above object, a communication device according to a first aspect of the present invention includes a communication circuit for performing wireless transmission / reception using a channel in which a wireless communication period is allocated to each communication device in a time division manner. The communication circuit specifies a reception-only communication period assigned to the channel based on the management data received by the communication circuit, and the communication circuit waits or waits for reception when a predetermined condition is not satisfied in the reception-only communication period. And a control circuit that controls the communication circuit to perform transmission when a predetermined condition is satisfied.

The operation of the communication device of the first invention is as follows. The communication circuit performs wireless transmission / reception using a channel in which a wireless communication period is assigned to each communication device in a time division manner. Then, the control circuit specifies the reception-only communication period assigned to the channel based on the management data received by the communication circuit. Then, the control circuit controls such that the communication circuit waits for reception or waits for reception when a predetermined condition is not satisfied during the reception-only communication period. Further, the control circuit controls so that the communication circuit performs transmission when a predetermined condition is satisfied during the reception-only communication period.

Further, in the communication device of the first invention, preferably, the control circuit transmits the notification to another communication device when the communication circuit receives a predetermined notification during the reception-only communication period. The communication circuit is controlled to do so. Further, in the communication device of the first aspect of the invention, preferably, the communication circuit performs wireless transmission / reception on a frame-by-frame basis using the channel to which the wireless communication period is assigned to each communication device. The communication device of the first invention is preferably
The reception-only communication period is defined at predetermined time intervals. Further, in the communication device of the first invention, preferably, the communication circuit performs wireless communication by spread spectrum.

A communication device according to a second aspect of the present invention includes a communication circuit that performs wireless transmission using a channel in which a wireless communication period is assigned to each communication device in a time division manner and a reception-only communication period is provided at a predetermined time interval, If the specified conditions are met,
And a control circuit that controls the communication circuit to continuously transmit a predetermined notification for at least the predetermined time interval.

The operation of the communication device of the second invention is as follows. The communication circuit performs wireless transmission using a channel in which a wireless communication period is assigned to each communication device in a time division manner and a reception-only communication period is provided at predetermined time intervals. Then, when the control circuit satisfies a predetermined condition, the communication circuit controls the communication circuit to continuously transmit the predetermined notification for at least the predetermined time interval.

The communication device of the second invention preferably further comprises a power supply circuit, and the control circuit supplies power to the communication circuit by the power supply circuit when the predetermined condition is not satisfied. Is stopped, the power supply by the power supply circuit to the communication circuit is started when the predetermined condition is satisfied, and the communication circuit is controlled to transmit the predetermined notification.

The communication device of the third invention is a communication circuit for performing wireless transmission using a channel in which a wireless communication period is assigned to each communication device in a time division manner and a reception-only communication period is provided at predetermined time intervals. And a control circuit that, when a predetermined condition is satisfied, controls the communication circuit to transmit a predetermined notification at an interval corresponding to the wireless communication period so as to continuously transmit at least the predetermined time interval. Have.

The operation of the communication device of the third invention is as follows. The communication circuit performs wireless transmission using a channel in which a wireless communication period is assigned to each communication device in a time division manner and a reception-only communication period is provided at predetermined time intervals. Then, when the control circuit satisfies a predetermined condition, the communication circuit controls the communication circuit to transmit a predetermined notification continuously at least for the predetermined time interval at an interval corresponding to the wireless communication period. To do.

A communication system according to a fourth aspect of the present invention is a communication system which has a plurality of communication devices, and performs wireless transmission / reception using a channel to which a plurality of communication devices are assigned time-division wireless communication periods. The communication device specifies a reception-only communication period assigned to the channel based on management data received by the communication device, and the communication circuit receives the reception-only communication period when a predetermined condition is not satisfied in the reception-only communication period. Alternatively, it waits for reception, and when a predetermined condition is satisfied, the communication circuit transmits a predetermined notification.

A communication method according to a fifth aspect of the invention is a communication method performed by a communication device that performs wireless transmission / reception using a channel in which a wireless communication period is allocated to each communication device in a time division manner, based on received management data. When the dedicated communication period assigned to the channel is specified, and when the predetermined condition is not satisfied in the specified dedicated communication period, the communication circuit waits or waits for reception, and when the predetermined condition is satisfied. Then, the communication circuit transmits a predetermined notification.

A communication method according to a sixth aspect of the present invention is a communication method performed by a communication device, which uses a channel in which a wireless communication period is allocated to each communication device in a time division manner and a reception-only communication period is provided at a predetermined time interval. Wirelessly, and when a predetermined condition is satisfied, the communication circuit continuously transmits a predetermined notification for at least the predetermined time interval.

A communication method according to a seventh aspect of the invention is a communication method performed by a communication device, which uses a channel in which a wireless communication period is allocated to each communication device in a time division manner and a reception-only communication period is provided at a predetermined time interval. Wireless transmission, and when a predetermined condition is satisfied, the communication circuit gives a predetermined notification,
At least the predetermined time interval is continuously transmitted at intervals corresponding to the wireless communication period.

[0017]

DETAILED DESCRIPTION OF THE INVENTION A communication system according to an embodiment of the present invention will be described below. FIG. 1 is an overall configuration diagram of a communication system 1 of this embodiment. As shown in FIG. 1, the communication system 1 includes, for example, an STB (Set Top Box).
11, TV receiver 12, telephone 13, printer 14, P
C (Personal Computer) 15, sensor 16, refrigerator 17
And a wall clock 18, which are arranged in the home.

STB 11, TV receiver 12, telephone 1
3, the printer 14 and the PC 15 have a UWB transmission / reception function and correspond to the communication device of the first invention of the present invention. The UWB transmission / reception is performed using a single channel. UWB transmission / reception is one of wireless communications, and spread spectrum spreads the frequency to 1 GHz or more (for example, 2 to 3 GHz
Transmission and reception are performed by spreading the signal in the wide frequency band of z). At this time, since the transmitted / received signal is as strong as noise, it does not interfere with a wireless device using the same frequency band and consumes less power.

Sensor 16, refrigerator 17 and wall clock 1
8 has a UWB transmission function, and corresponds to the communication device of the second invention of the present invention. The STB 11 functions as a base station for UWB communication, transmits a control signal to a communication device such as a television receiver 12, a telephone 13, a printer 14 and a PC 15, and allocates the wireless communication period defined by the communication frame to the communication device. (Source allocation of wireless section),
The communication device is controlled to perform UWB communication using the allocated communication frame. The communication frame cycle is, for example, 2 ms. In the present embodiment, as shown in FIG. 2, in the communication frame, in addition to the normal communication frame to which the transmission authority is assigned by the STB 11, for example, a receive-only frame (receive-only communication period of the present invention) is provided at predetermined time intervals. It is prescribed. In the reception-only frame, each communication device receives or waits for reception when a predetermined condition is not satisfied, for example, when no emergency has occurred, and when the predetermined condition is satisfied, for example, an emergency has occurred. In some cases, a predetermined emergency notification is given. That is,
In the reception-only frame, each communication device is only permitted to transmit an emergency notification. The receive-only frame is, for example, 100
Exists once in a communication frame. The predetermined conditions include, in addition to the occurrence of an emergency, detection of a preset state of the communication device, that the communication device is not assigned a normal communication period at that time, or For example, the communication device may be set to allow data transmission in the reception-only frame. Each communication device specifies the timing of the receive-only frame based on the management data (management data of the present invention) in the control slot in each communication frame.

Further, the sensor 16, the refrigerator 17, and the wall clock 18 have the UWB transmission function turned off in the normal state, and when an emergency occurs in the internal state, the UWB transmission function is turned on to cause the emergency situation. The emergency notification for notifying is transmitted continuously for a period corresponding to 100 communication frames, for example. For example, as shown in FIG.
Transmits the emergency notification by UWB, and the television receiver 12 receives the emergency notification in a receive-only frame. Then, the television receiver 12 UWs the received emergency notification to the PC 15.
B is transmitted, and the PC 15 displays an emergency notification on the screen.

The components shown in FIG. 1 will be described below. [STB11] FIG. 4 is a functional block diagram of the STB11 shown in FIG. As shown in FIG. 4, the STB 11 has, for example, an antenna 30, a UWB transmitting / receiving unit 31, an STB function unit 32, a liquid crystal display 33, and a microcomputer 34. Here, the UWB transceiver 31 is the first
Corresponding to the communication circuit of the present invention, the microcomputer 34
Corresponds to the control circuit of the first invention.

The UWB transmission / reception unit 31 performs UWB transmission / reception with another communication device via the antenna 30. The STB function unit 32 realizes a normal STB function. The liquid crystal display 33 displays a screen according to the display signal from the microcomputer 34. Microcomputer 34
Transmits a control signal to another communication device via the UWB transmitting / receiving unit 31, and manages UWB communication using the communication frame shown in FIG. Further, the microcomputer 34 uses the receive-only frame defined by the control slot in the communication frame to receive or receive the UWB transmitter / receiver 31 when no emergency occurs (when the predetermined condition of the present invention is not satisfied). When controlling to wait for reception and an emergency occurs (when the predetermined condition of the present invention is satisfied),
The UWB transmission / reception unit 31 sends an emergency notification to notify the emergency.
UWB transmission via. Further, when the UWB transmitting / receiving unit 31 receives an emergency notification from another communication device, the microcomputer 34 transmits the emergency notification to the other communication device via the UWB transmitting / receiving unit 31.

[Television Receiver 12] FIG. 5 is a functional block diagram of the television receiver 12 shown in FIG. As shown in FIG. 5, the television receiver 12 includes, for example, an antenna 40,
It has a UWB transmitting / receiving unit 41, a television function unit 42, and a microcomputer 44. Here, the UWB transceiver unit 4
1 corresponds to the communication circuit of the first invention, and the microcomputer 44 corresponds to the control circuit of the first invention.

The UWB transmitting / receiving unit 41 performs UWB transmission / reception with another communication device via the antenna 40. The TV function unit 42 realizes a normal TV image receiving function. The microcomputer 44 specifies the receive-only frame based on the control slot in the communication frame received by the UWB transceiver 41, and when no emergency occurs during the receive-only communication period (predetermined in the present invention). If the condition is not satisfied), the UWB transmitter / receiver unit 41 controls to receive or wait for reception, and when an emergency occurs (when the predetermined condition of the present invention is satisfied), the emergency is notified. UW with emergency notification together with ID of TV function unit 42
UWB transmission is performed via the B transmission / reception unit 41. Further, the microcomputer 44, when the UWB transceiver unit 41 receives an emergency notification from another communication device, the UWB transceiver unit 4
The emergency notification is transmitted to another communication device via 1.

The printer 14 and the PC 15 have the same functions as the television receiver 12 shown in FIG. 6 except for the television function section 42.

[Sensor 16] FIG. 6 is a functional block diagram of the sensor 16 shown in FIG. As shown in FIG. 6, the sensor 16 includes, for example, an antenna 50, a UWB transmitter 51,
It has a sensor function unit 52, a microcomputer 54, a battery 55 and a power supply IC 56. Where UWB
The transmitter / receiver 51 corresponds to the communication circuit of the second invention, and the microcomputer 54 corresponds to the control circuit of the second invention.

The UWB transmitter 51 performs UWB transmission to another communication device via the antenna 50. Sensor function part 5
Reference numeral 2 denotes, for example, an intruder detection sensor, which outputs a detection signal indicating the fact to the microcomputer 54 when an intruder is detected. The battery 55 supplies electric power for driving the UWB transmitter 51. Power IC 56
Controls the power supply from the battery 55 to the UWB transmitter 51 based on the control signal from the microcomputer 54. When the detection signal indicating that an intruder has been detected is input from the sensor function unit 52, the microcomputer 54 causes the battery 55 to supply the power IC 56 to the power IC 56.
Turn on the power supply to the. Then, the microcomputer 54 sends an emergency notification to notify the sensor 16 of an emergency.
With the ID of, for example, the UWB transmitter 5 at random continuously for a period (100 × 2 ms) corresponding to 100 communication frames, which is a time interval to which a receive-only frame is assigned.
1 to send multiple times.

Hereinafter, an operation example of the communication system 1 shown in FIG. 1 will be described. [First Operation Example] In the operation example, a case where the television receiver 12 shown in FIG. 1 detects an emergency is described. In the following operation, the television receiver 12 and the PC 15 specify the timing of the receive-only frame, if necessary, based on the control slot in the received frame shown in FIG.
FIG. 7 is a flowchart for explaining the operation example. Step ST1: When the microcomputer 44 of the television receiver 12 shown in FIG. 5 detects some emergency such as an abnormality of the television function unit 42, step S1:
The process proceeds to T2. Step ST2: The microcomputer 44 of the television receiver 12 identifies the next receive-only frame based on the control slot in the communication frame received by the UWB transceiver 41. Step ST3: For example, the microcomputer 44 generates an emergency notification indicating the content of the abnormality, and transmits the emergency notification via the UWB transceiver 41 using the reception-only frame specified in step ST2. In the period corresponding to the reception-only frame, STB 11, telephone 13, printer 14, and PC 15 receive or wait for reception. The emergency notification is received by, for example, the UWB transmitting / receiving unit 31 of the STB 11 shown in FIG.

Step ST4: The microcomputer 34 of the STB 11 shown in FIG.
The UWB transmitter / receiver 3 sends the emergency notification received by the transmitter / receiver 31.
1 to PC15. Microcomputer 34
The transfer of the emergency notification by the above may be performed using the normal frame shown in FIG. 2 or may be performed using the reception-only frame.

Step ST5: The PC 15 executes the step S
If the emergency notification received at T4 indicates that a failure has occurred in the television receiver 12, for example, W of the failure repair service
The eb page is automatically accessed and a screen corresponding to the web page is displayed. Step ST6: The PC 15 transmits an emergency notification reception confirmation indicating that the emergency notification has been received to the STB 11. The emergency notification reception confirmation is received by the UWB transmitting / receiving unit 31 of the STB 11 shown in FIG. Step ST7: The microcomputer 34 of the STB 11 shown in FIG. 4 transfers the emergency notification reception confirmation received in step ST6 from the UWB transceiver 31 to the television receiver 12.

[Second Operation Example] In this operation example, a case where the sensor 16 detects an emergency will be described. FIG. 8 is a flowchart for explaining the operation example. In the initial state, the power supply from the battery 55 to the UWB transmitter 51 via the power IC 56 shown in FIG. 6 is stopped, and the UWB transmitter 51 is inactive.

Step ST11: Sensor 16 shown in FIG.
When the sensor function unit 52 detects the intruder, for example, a detection signal indicating that is output to the microcomputer 54. Based on the detection signal, the microcomputer 54 determines that an emergency situation has been detected, and proceeds to step ST1.
Proceed to the process of 2. Step ST12: The microcomputer 54 outputs a start signal for the power IC 56. As a result, the power supply IC 56 supplies power from the battery 55 to the UWB transmitter 51, and the UWB transmitter 51 is activated. Step ST13: The microcomputer 54 causes the UWB transmitter 51 to continuously transmit an emergency notification for notifying an emergency, for example, for a period corresponding to 100 communication frames. The emergency notification is, for example, in a reception-only frame, the UWB transmission / reception unit 41 of the television receiver 12 shown in FIG.
Will be received at. At this time, since there is always one reception-only frame between 1000 communication frames, the emergency notification is transmitted and received without fail. After transmitting the emergency notification, the microcomputer 54 controls the power IC 56 to stop the power supply from the battery 55 to the UWB transmitter 51, and deactivates the UWB transmitter 51.

Step ST14: The microcomputer 44 of the television receiver 12 shown in FIG.
The transfer request for the emergency notification received in 3 is transmitted to the STB 11. The emergency notification is transmitted using, for example, the normal communication frame shown in FIG. Step ST15: In step ST14, the microcomputer 34 of the STB 11 shown in FIG.
UWB transfer permission notification for the transfer request received from
The transmission / reception unit 31 transmits to the television receiver 12. The transfer permission notification is transmitted using, for example, the normal communication frame shown in FIG.

Step ST16: The microcomputer 44 of the television receiver 12 shown in FIG.
The UWB transmitter 41 transfers the emergency notification received from the sensor 16 in step 4 to the STB 11. The transfer of the transfer permission notification is performed using, for example, the normal communication frame illustrated in FIG. Step ST17: The microcomputer 34 of the STB 11 shown in FIG.
The emergency notification received from 2 is transferred from the UWB transmitting unit 31 to the PC 15. The transfer of the transfer permission notification is performed using, for example, the normal communication frame illustrated in FIG.

Step ST18: When the emergency notification received in step ST17 indicates, for example, intruder detection, the PC 15 accesses the server device of the security company, performs a process of notifying it, and outputs an alarm. To do. Step ST19: The PC 15 transmits an emergency notification reception confirmation indicating that the emergency notification has been received to the STB 11. The transmission of the emergency notification reception confirmation is performed using, for example, the normal communication frame shown in FIG. Step S20: The microcomputer 34 of the STB 11 shown in FIG. 4 transfers the emergency notification reception confirmation received in step ST19 from the UWB transmitting / receiving unit 31 to the television receiver 12. The transmission of the emergency notification reception confirmation is performed using, for example, the normal communication frame shown in FIG.

As described above, according to the communication system 1, when the communication device in the home performs the low power consumption wireless communication of 1 channel by UWB, each communication device uses the receive-only frame for other communication. It is possible to reliably send and receive an emergency notification to the device within a predetermined time. In the communication system 1, by using the reception-only frame in this way, the transmission / reception of the emergency notification does not affect the communication between the communication devices using the normal frame. This is particularly effective for AV transmission that requires real-time processing. Further, according to the sensor 16 of the communication system 1, the battery 55 to the UWB transmitter 51
Since the power supply to the sensor function unit 52 is performed only when the sensor function unit 52 detects an emergency, the battery 55 can be downsized. Therefore, the emergency notification transmission function can be easily incorporated into various devices.

The present invention is not limited to the above embodiments. For example, in the above-described embodiment, the microcomputer 54 shown in FIG. 6 exemplifies a case where the UWB transmitting unit 51 continuously transmits the emergency notification for a period corresponding to 100 communication frames, which is a time interval to which the reception-only frame is allocated. However, the microcomputer 54, for example,
When holding the period (2ms) of the communication frame,
The emergency notification may be transmitted continuously every 2 ms for a period of 100 communication frames. In this case, the sensor 1
6 corresponds to the third invention.

Further, in the above-described embodiment, steps ST14, ST15, ST16, ST17, S shown in FIG.
Although the case where T19 and ST20 are performed using the normal communication frame has been illustrated, the timing of the reception-only frame may be specified and the reception-only frame may be used.

[0039]

As described above, according to the present invention,
A communication device capable of reliably transmitting and receiving predetermined information within a predetermined period when a predetermined condition is satisfied when performing wireless transmission and reception using a channel in which a wireless communication period is allocated to each communication device in a time division manner, and a system thereof. And a method therefor can be provided.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a communication system according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining a communication frame used in the communication system shown in FIG.

FIG. 3 is a diagram for explaining an operation example of the communication system of the present embodiment shown in FIG.

FIG. 4 is a functional block diagram of the STB shown in FIG.

FIG. 5 is a functional block diagram of the television receiver shown in FIG.

FIG. 6 is a functional block diagram of the sensor shown in FIG.

7 is a flowchart for explaining a case where the television receiver detects an emergency in the communication system shown in FIG.

8 is a flowchart for explaining a case where a sensor detects an emergency in the communication system shown in FIG.

[Explanation of symbols]

11 ... STB, 12 ... TV receiver, 13 ... Telephone, 14
... printer, 15 ... PC, 16 ... sensor, 17 ... refrigerator, 18 ... wall clock, 30 ... antenna, 31 ... UWB transmitting / receiving unit, 32 ... STB function unit, 33 ... liquid crystal display, 34 ... microcomputer, 40 ... antenna, 4
DESCRIPTION OF SYMBOLS 1 ... UWB transmission / reception part, 42 ... Television function part, 44 ... Microcomputer, 50 ... Antenna, 51 ... UWB transmission part, 52 ... Sensor function part, 54 ... Microcomputer, 55 ... Battery, 56 ... Power supply IC

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5K028 BB06 CC02 CC05 EE08 KK01                       KK12 LL12 LL22 RR02                 5K033 CA11 DA17 DB25                 5K067 AA33 BB21 CC04 CC10 EE71                       GG03 JJ20                 5K101 KK12 KK14 LL11 SS01

Claims (11)

[Claims] 1. A communication circuit for performing wireless transmission and reception using a channel in which a wireless communication period is allocated to each communication device in a time division manner, and a reception-only circuit allocated to the channel based on management data received by the communication circuit. The communication period is specified, and in the reception-only communication period, the communication circuit performs reception or waiting for reception when the predetermined condition is not satisfied, and the communication circuit performs transmission when the predetermined condition is satisfied. Device having a control circuit for controlling. 2. The control circuit, when the communication circuit receives a predetermined notification during the reception-only communication period, controls the communication circuit to transmit the notification to a predetermined communication device. The communication device according to 1. 3. The communication device according to claim 1, wherein the communication circuit performs wireless transmission / reception using the channel in which the reception-only communication period is assigned to each communication device in units of frames. 4. The communication device according to claim 1, wherein the reception-only communication period is defined at predetermined time intervals. 5. A communication circuit that performs wireless transmission using a channel in which a wireless communication period is assigned to each communication device in a time division manner and a reception-only communication period is provided at predetermined time intervals, and when a predetermined condition is satisfied. And a control circuit that controls the communication circuit to continuously transmit a predetermined notification for at least the predetermined time interval. 6. A power supply circuit is further provided, and the control circuit, when the predetermined condition is not satisfied,
The power supply by the power supply circuit to the communication circuit is stopped, and the power supply by the power supply circuit to the communication circuit is activated when the predetermined condition is satisfied, and the communication circuit transmits the predetermined notification. The communication device according to claim 5, which is controlled as follows. 7. A communication circuit that performs wireless transmission using a channel in which a wireless communication period is allocated to each communication device in a time division manner and a reception-only communication period is provided at a predetermined time interval, and when a predetermined condition is satisfied. And a control circuit that controls the communication circuit to continuously transmit a predetermined notification at least at an interval corresponding to the wireless communication period for the predetermined time interval. 8. A communication system comprising a plurality of communication devices, and performing wireless transmission / reception using a channel in which a wireless communication period is allocated to the plurality of communication devices, the communication device comprising: The reception-only communication period assigned to the channel is specified based on the management data received by the device, and in the reception-only communication period, the communication circuit performs reception or reception waiting when a predetermined condition is not satisfied, A communication system in which the communication circuit transmits a predetermined notification when the condition (1) is satisfied. 9. A communication method performed by a communication device that performs wireless transmission / reception using a channel in which a wireless communication period is allocated to each communication device in a time division manner, the communication method being allocated to the channel based on received management data. A reception-only communication period is specified, and in the specified reception-only communication period, the communication circuit waits for reception or reception when a predetermined condition is not satisfied, and when the predetermined condition is satisfied, the communication circuit determines a predetermined condition. A communication method that sends a notification. 10. A communication method performed by a communication device, wherein wireless communication is performed using a channel in which a wireless communication period is assigned to each communication device in a time division manner and a reception-only communication period is provided at predetermined time intervals, A communication method in which the communication circuit continuously transmits a predetermined notification for at least the predetermined time interval when a predetermined condition is satisfied. 11. A communication method performed by a communication device, wherein wireless communication is performed using a channel in which a wireless communication period is allocated to each communication device in a time division manner and a reception-only communication period is provided at predetermined time intervals, A communication method in which, when a predetermined condition is satisfied, the communication circuit continuously transmits a predetermined notification at an interval corresponding to the wireless communication period for at least the predetermined time interval.