JP2011024013A - Wireless communication method and wireless sensor network system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless communication method and a wireless sensor network system for promptly and efficiently transmitting emergency information while avoiding interferences in the system. <P>SOLUTION: A terminal separately transmits in a time-division manner a regular transmission frame for regular data and an emergency transmission frame for emergency data by using the same frequency in an area. The wireless communication method and the wireless communication sensor network system use no emergency transmission frame when there is no emergency data, and further, transmit emergency data by the emergency transmission frame instead of the regular transmission frame in order of priority of emergency. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a wireless sensor network system, and more particularly to a wireless communication method and a wireless sensor network system capable of transmitting emergency information quickly and efficiently while avoiding interference in the system.

[Conventional technology]
[Overview of sensor network]
Services such as electricity, gas, water and sewage are provided in office buildings, factories, hotels, department stores, hospitals, etc., and sensors are connected to wireless terminals in order to monitor their provision status. Wireless sensor network systems that collect monitoring status data using signals are known.

  The wireless sensor network system not only monitors whether services such as electricity and gas are normally provided, but can also monitor fires and intrusions from the outside, and control it to provide services without waste. It has been in the limelight as a basic technology for energy conservation measures to control global warming.

[Related technologies]
As related prior art, Japanese Patent Laid-Open No. 2002-006937 “Equipment Management Method, Equipment Management System, and Equipment Management Relay Server” (Applicant: Tokyo Electric Power Company, Inc .: Patent Document 1), Japanese Patent Application Laid-Open No. 2007-184701. “Sensor Network System Maintenance / Maintenance Service System” (Applicant: Hitachi Electronic Service Co., Ltd .: Patent Document 2), JP 2007-243478 “Sensor Network System” (Applicant: Hitachi, Ltd .: Patent) There is literature 3).

  Patent Document 1 shows that in an equipment management system, information from sensors is aggregated in a gateway controller and transmitted to an equipment management relay server, and information is selected and transmitted to a server of a service provider. .

  Patent Document 2 shows that in a maintenance / maintenance service system for a sensor network system, when an operation policy is designed / changed by a policy control server, settings of a plurality of sensor nodes and wireless AP devices are collectively changed. Yes.

  In Patent Document 3, in a sensor network system, a measurement value detected by a sensor is transmitted as sensing data to a base station by wireless communication, and the base station converts the data into a network-usable format such as XML and transmits data. It is shown that sensing data with the meaning of is generated and transmitted to a network server.

JP 2002-006937 A JP 2007-184701 A JP 2007-243478 A

  However, in the conventional sensor network system, it is necessary to construct a system so that signals do not interfere with each other in its own system, and it is difficult to transmit emergency transmission data more quickly and efficiently with respect to scheduled transmission data. There was a problem that there was.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a wireless communication method and a wireless sensor network system capable of transmitting emergency information quickly and efficiently while avoiding interference in the own system.

  The present invention for solving the problems of the conventional example described above is that the access point receives data wirelessly transmitted from a terminal connected to a sensor provided in the area, and the data received from the access point is relayed by wireless communication. A wireless communication method for transmitting data to each terminal, wherein each terminal uses the same frequency for each area, and a period for transmitting data is determined in a time-sharing manner. Emergency transmission frame can be transmitted and the terminal determines whether it is urgent by comparing the data input from the connected sensor with the threshold stored internally. Sends data but does not use an emergency transmission frame. If it is an emergency, it sends emergency data using an emergency transmission frame, and sends a fixed transmission frame from the terminal. If the data cannot be received at the access point, the terminal transmits the scheduled data again in the scheduled transmission frame, and if the emergency data transmitted from the terminal in the emergency transmission frame cannot be received at the access point, the terminal again transmits the emergency transmission frame. And the access point transmits the received scheduled data and emergency data to the repeater at different timings.

  In the above wireless communication method, when the terminal makes an emergency determination on data input from a sensor, the emergency priority is determined. The emergency data is transmitted by an emergency transmission frame.

  According to the present invention, in the above wireless communication method, the communication method from the terminal to the access point is the first communication method, the communication method from the access point to the repeater is the second communication method, and the first communication method and the first communication method are the same. The communication method of 2 is a different communication method, the first communication method is a communication method that consumes less power than the second communication method, and the second communication method is a communication method that is less than the first communication method. It is characterized by a communication method with a long distance.

  The present invention relates to a relay device provided in a district having a plurality of areas, a terminal connected to a sensor provided in the area, and a relay device that receives data wirelessly transmitted from the terminal provided for each area. Wireless sensor network system having an access point for wireless transmission to a machine, the terminal uses the same frequency for each area, and a period for transmitting data is determined in a time-sharing manner. It is possible to send data with the scheduled transmission frame and emergency transmission frame for emergency data, and determine whether it is urgent by comparing the data input from the connected sensor with the threshold stored internally. , Do not use urgent transmission frame but send urgent data by urgent transmission frame in case of emergency, If the scheduled data sent in the hourly transmission frame cannot be received by the access point, send the scheduled data again in the scheduled transmission frame, and if the emergency data sent in the emergency transmission frame cannot be received by the access point, again in the emergency transmission frame The emergency data is transmitted, and the access point transmits the received scheduled data and emergency data to the repeater at different timings.

  In the wireless sensor network system, when the terminal makes an emergency determination on data input from the sensor, the priority of the emergency is determined, and if it is equal to or higher than a specific priority, it is replaced with a scheduled transmission frame. The emergency data is transmitted by an emergency transmission frame.

  The present invention provides the wireless sensor network system in which the communication method from the terminal to the access point is the first communication method, the communication method from the access point to the relay is the second communication method, The second communication method is a different communication method, the first communication method is a communication method with lower power consumption than the second communication method, and the second communication method is different from the first communication method. The communication system has a long communication distance.

  In the wireless sensor network system according to the present invention, when an access point is installed for a repeater, the access point transmits an installation signal, receives a response signal for the installation signal, and receives a response signal on the display unit. And the repeater returns a response signal to the installation signal from the access point.

  In the wireless sensor network system, when a terminal is installed in an area with respect to an access point, the terminal transmits an installation signal, receives a response signal for the installation signal, and receives a response signal on the display unit. And the access point returns a response signal to the installation signal from the terminal.

  According to the present invention, there is provided a wireless communication method in which an access point receives data wirelessly transmitted from a terminal connected to a sensor provided in an area, and transmits data received from the access point to a repeater by wireless communication. Thus, each terminal uses the same frequency for each area, and a period for transmitting data is determined in a time-sharing manner, and a scheduled transmission frame for scheduled data and an emergency transmission frame for emergency data can be transmitted within the period. Yes, the terminal compares the data input from the connected sensor with the threshold stored internally to determine whether it is urgent. If it is not urgent, the terminal transmits the scheduled data using the scheduled transmission frame. If it is not used and urgent, emergency data is transmitted using an emergency transmission frame. If it is not possible to transmit data, the terminal transmits the scheduled data again in the scheduled transmission frame. If the emergency data transmitted from the terminal in the emergency transmission frame cannot be received by the access point, the terminal transmits the emergency data again in the emergency transmission frame. In addition, since the access point has a wireless communication method and wireless sensor network system in which the received scheduled data and emergency data are transmitted to the repeater at different timings, the emergency information can be quickly and efficiently avoided by avoiding interference in its own system. Can be transmitted effectively.

  According to the present invention, when the terminal urgently determines the data input from the sensor, the terminal determines the priority of the emergency, and if it is equal to or higher than the specific priority, the emergency data is transferred to the emergency transmission frame instead of the scheduled transmission frame. Since the wireless communication method and the wireless sensor network system transmit by a transmission frame, emergency data can be transmitted by an emergency transmission frame instead of a regular transmission frame and determined in a time division manner if the priority is higher than a specific priority. Emergency data can be transmitted even in an emergency transmission frame, and emergency data can be transmitted reliably.

1 is a schematic diagram of a wireless sensor network system according to an embodiment of the present invention. It is a figure which shows the outline | summary of a district. It is a block diagram of an access point. It is a figure which shows a data format. It is a transmission time chart. It is explanatory drawing of the confirmation mode at the time of installation.

Embodiments of the present invention will be described with reference to the drawings.
[Outline of the embodiment]
A wireless sensor network system according to an embodiment of the present invention includes a repeater provided in a district having a plurality of areas, a terminal connected to a sensor provided in the area, and provided for each area. An access point that receives wirelessly transmitted data and wirelessly transmits the data to the relay station, the terminal uses the same frequency for each area, and a time period for transmitting data is determined in a time-sharing manner. , It is possible to transmit data in the regular transmission frame for regular data and the emergency transmission frame for emergency data, and determine whether it is urgent by comparing the data input from the connected sensor with the threshold held internally, If it is not urgent, send the scheduled data by the scheduled transmission frame, but do not use the urgent transmission frame. If the scheduled data sent in the scheduled transmission frame cannot be received by the access point, the scheduled data will be sent again in the scheduled transmission frame. If the emergency data sent in the emergency transmission frame cannot be received by the access point, the emergency data will be sent again. Emergency data is transmitted in a transmission frame, and the access point transmits the received scheduled data and emergency data to the repeater at different timings, and the emergency information can be promptly and efficiently avoided by avoiding interference in its own system. Can be sent to.

  Further, in the wireless sensor network system according to the embodiment of the present invention, when the terminal urgently determines the data input from the sensor, the urgent priority is determined. Instead of the regular transmission frame, the emergency data is transmitted by the emergency transmission frame, and the emergency data can be transmitted reliably.

[Overall system configuration: Fig. 1]
A wireless sensor network system (this system) according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic diagram of a wireless sensor network system according to an embodiment of the present invention.
As shown in FIG. 1, this system includes a repeater 1, a router 2 corresponding to a district (a set of areas), an Internet network 3, a firewall 41, a router 42 for in-house intranets, a data server 43, A monitoring terminal 44, an in-house SMTP (Simple Mail Transfer Protocol) server 45, an ISP (Internet Service Provider) server 5, a mail recipient's PC (computer) 6, a server 7 such as a mobile operator, a mail It basically has a portable terminal 8 of the receiver.

The district-compatible router 2 is connected to the Internet network 3 via a VPN (Virtual Private Network) network, and an ISP server 5 and a server 7 such as a mobile operator are also connected to the Internet network 3.
In addition, the firewall 41 of the in-house intra network is connected to the external Internet network 3 and is also connected to the router 42 for in-house intra, the router 42 is connected to the data server 43 and the SMTP server 45, and the monitoring terminal 45 is Connected to the data server 43.

  Here, the SMTP server has been described for in-house use, but the SMTP server may be connected to the Internet network 3 for external use.

[System components]
Each part of this system will be specifically described.
[Repeater 1]
The repeater 1 has an IP address, receives a signal from a wireless terminal existing in the area, and outputs it to the router 20. The configuration of the repeater 1 and the arrangement of devices in the district will be described later.
[Router 2]
The router 2 transmits a signal from the repeater 1 to the data server 43 via the Internet network 3.

[In-house intranet]
The firewall 41 is a device for protecting computers and data in the in-house intra network against attacks from the outside via the Internet network 3.
The router 42 distributes data input from the firewall 41 to the data server 43 or the SMTP server 45, and outputs data from the data server 43 or the SMTP server 45 to the firewall 41.

The data server 43 inputs the measurement data collected in each district via the router 42, stores (accumulates) it in the storage means, and displays and outputs the measurement data in response to a request from the monitoring terminal 44.
In addition, the data server 43 stores a threshold value for determining an abnormality in the input measurement data in the storage unit, and compares the measurement data with the threshold value to determine an abnormality. 44 and the SMTP server 45.

The monitoring terminal 44 requests display of the measurement data stored in the data server 43 and displays the measurement data on the display device.
In addition, when a notification of an abnormal state is input from the data server 43, the monitoring terminal 44 displays information on the abnormal state on the display device.

The in-house SMTP server 45 inputs the notification of the abnormal state from the data server 43, and performs mail transmission in order to notify the administrator (mail recipient) of the abnormal state.
The mail created by the SMTP server 45 is sent to the PC 6 via the ISP server 5 if the mail address of the manager in charge stored in the SMTP server 45 is the destination, and the receiving terminal is a PC. If so, it is transmitted to the portable terminal 8 via the server 7 such as the portable operator.

[ISP system]
If the mail transmitted from the SMTP server 45 is managed by the provider, the ISP server 5 transmits a mail notifying the abnormal state to the PC 6 as the mail destination.
The PC 6 is a computer whose mail address is managed by the ISP server 5, and sends and receives mail via the ISP server 5.

[Mobile operator equipment]
If the mail transmitted from the SMTP server 45 is managed by the mobile operator, the server 7 such as the mobile operator transmits a mail notifying the abnormal state to the mobile terminal 8 that is the destination of the mail.
The mobile terminal 8 is a mobile phone or the like whose mail address is managed by the mobile operator etc. server 7, and sends and receives mail via the mobile operator etc. server 7.

  The firewall 41, the data server 43, the monitoring terminal 44, the SMTP server 45, the ISP server 5, the PC 6, the mobile operator, etc. server 7 described above are composed of computers, and a control unit (control means) that performs processing, a program And a storage unit (storage unit) for storing necessary data and an interface unit for connection to a network. These devices execute various processes by starting a program stored in a storage unit by a control unit.

[District overview: Figure 2]
Next, an outline of the district will be described with reference to FIG. FIG. 2 is a diagram showing an outline of the district.
As shown in FIG. 2, the district (for example, district A) is composed of a plurality of areas (areas A to C), and the repeater 1a is a repeater for the plurality of areas.
In the area, access points 11a to 11c are arranged in the area, and perform wireless communication with the terminals 12a to 12c in the area.
Each terminal 12 is connected to a sensor and monitors the provision of services such as gas.

The repeater 1a has an IP address and is connected to the router 2a to transmit measurement data in the sensor to the router 2a.
The router 2 a transmits the measurement data from the repeater 1 a to the in-house intra data server 43 via the Internet network 3.

Different frequencies are assigned to each area, and the terminals 12 in the same area transmit measurement data to the access point 11 in a time division manner using, for example, a weak radio wave communication method using the frequencies assigned to the areas.
The access point 11 temporarily stores the measurement data received from each terminal 12 in the storage unit.

In addition, each access point 11 transmits measurement data to the repeater 1a in a time division manner using, for example, a specific low power communication method using a frequency different from the frequency assigned to the area.
That is, each access point 11 transmits the measurement data stored in the storage unit to the repeater 1a during the assigned time zone.
Here, the weak radio wave communication method consumes less power than the specific low power communication method, and the specific low power communication method has a longer communication distance than the weak radio wave communication method.
Since the terminal 12 is connected to the sensor, many of them are battery driven, and it is preferable that the power consumption is smaller. Further, since a long distance is assumed between the access point 11 and the repeater 1a, a longer communication distance is suitable.

[Composition of each part in the district: Fig. 3]
Next, the configuration of each part in the district will be described.
First, the configuration of the access point will be described with reference to FIG. FIG. 3 is a block diagram of the access point.
As illustrated in FIG. 3, the access point 11 includes a reception antenna 111, a reception unit 112, a control unit 113, a storage unit 114, a transmission unit 115, and a transmission antenna 116.

  The reception antenna 111 receives weak radio waves, and the control unit 113 causes the reception unit 112 to perform a reception operation when it is time to receive a radio signal from the terminal 12. The reception unit 112 receives a signal from the reception antenna 111. Is received by a weak radio wave communication method and output to the control unit 113, and the control unit 113 stores the data received by the reception unit 112 in the storage unit 114.

  In addition, when the transmission time zone for the repeater 1a is reached, the control unit 113 outputs the data stored in the storage unit 114 to the transmission unit 115, and the transmission unit 115 performs a data transmission process using a specific low power communication method. The signal is transmitted to the transmission antenna 116, and the transmission antenna 116 transmits a signal of a specific low power communication method.

  In FIG. 3, the configuration of the access point 11 is shown, but the configuration of the terminal 12 is the same. The output from the sensor is input to the reception unit by wire or wireless instead of the reception antenna, and the transmission unit is a weak radio wave. The transmission antenna transmits a weak radio wave by performing a transmission process using the above communication method.

  The configuration of the repeater 1a is also almost the same as that of the access point 11, and the receiving unit and the receiving antenna perform a receiving operation using a specific low power communication method, and the output is sent to the router 2a instead of the transmitting antenna. The signal is output from the transmission unit to the router 2a.

  As will be described later, the data transmission timing by the control unit of the terminal 12, the transmission / reception timing by the control unit of the access point 11, and the reception timing by the control unit of the repeater 1a are features in this embodiment.

[Data format: Fig. 4]
Next, a data format transmitted from the terminal 12 to the access point 11 in this system will be described with reference to FIG. FIG. 4 is a diagram illustrating a data format.
As shown in FIG. 4, the data format is a unit of 8 bits of terminal ID information (terminal identification information), followed by 4 bits of status display information, 20 bits of time information, and 48 bits of 16 bits of sensing data. Configured as data.

A threshold value for determining normality / abnormality of the measurement data is set in the storage unit of the terminal 12, and a state corresponding to the threshold value is output as state display information.
When there is no abnormality in the status display, information transmission is performed in a regular transmission frame.
When there is an abnormality in the status display, information is transmitted as an emergency transmission frame.

As status display information, as shown in FIG. 4, “1111”, “1110”, “1101”, and “1100” have the highest priority and indicate emergency transmission frames as indicating the occurrence of an external trigger.
In addition, “1011”, “1010”, “1001”, “1000” indicates the next highest priority order as an internal trigger occurrence, and “0111” indicates a battery voltage drop as an emergency transmission with the same priority order. It becomes a frame.

“0001” indicates time correction, and “0000” indicates transmission of a regular transmission frame at normal time. Other state display information is used as a spare.
The fixed-time transmission frame transmits 48-bit unit data 10 times (data for the past 10).

[Transmission time chart: Fig. 5]
Next, the transmission timing in the district will be described with reference to FIG. FIG. 5 is a transmission time chart. In FIG. 5, “ASC” indicates a terminal in area A, “AAP” indicates an access point in area A, “BSC” indicates a terminal in area B, and “BAP” indicates an area. B indicates an access point in B, “CSC” indicates a terminal in area C, “CAP” indicates an access point in area C, and “J-AP” indicates a repeater. Further, the horizontal axis of FIG. 5 indicates time and is expressed in seconds.

[Area A transmission processing]
As shown in FIG. 5, the transmission timing in the area is as follows. In area A, data transmission is performed as a scheduled transmission frame from the first terminal (ASC1) in area A in 0 to 8 seconds, and the access point in area A (AAP) receives the data.

  If ASC1 does not receive a reception response (ACK) from AAP, or if it receives a response (NACK) indicating that it could not be received, ASC1 transmits data again in 10 to 18 seconds. Receive.

  And AAP transmits the data received from ASC1 to J-AP in 20 to 21 seconds. The reason why the transmission time from the access point to the relay station is shorter than the transmission time from the terminal to the access point is because a communication method with a high transmission speed is adopted.

If there is emergency data in ASC1, the spontaneous data is transmitted to the AAP as an emergency transmission frame in 30 to 38 seconds. The AAP receives the spontaneous data.
When ACK is not obtained from AAP or when NACK is received, ASC1 performs data transmission again in 40 to 48 seconds, and AAP receives it.
And AAP transmits the data received from ASC1 to J-AP in 50 to 51 seconds.

If there is no emergency data, data transmission for 30 to 38 seconds and 40 to 48 seconds is not performed.
Whether or not there is urgent data is determined by comparing the threshold value stored in the storage unit in the terminal with the measured data, and when the control unit in the terminal determines that the threshold value has been exceeded, urgent data is generated. become.

Further, data transmission is performed as a scheduled transmission frame from the second terminal (ASC2) in area A in 60 to 68 seconds, and the AAP receives the data.
When ACK is not obtained from AAP or when NACK is received, ASC2 performs data transmission again in 70 to 78 seconds, and AAP receives it.
And AAP transmits the data received from ASC2 to J-AP in 80 to 81 seconds.

[Transmission processing of area B]
In area B, data transmission is performed as a scheduled transmission frame from the first terminal (BSC1) in area B in 10 to 18 seconds, and the access point (BAP) in area B receives the data.

When BSC1 cannot receive ACK from BAP or receives NACK, BSC1 performs data transmission again in 20 to 28 seconds, and BAP receives it.
And BAP transmits the data received from BSC1 to J-AP in 30 to 31 seconds.

Further, if there is emergency data in BSC1, the spontaneous data is transmitted to the BAP as an emergency transmission frame in 40 to 48 seconds. The BAP receives the spontaneous data.
When BSC1 cannot receive ACK from BAP or receives NACK, BSC1 performs data transmission again in 50 to 58 seconds, and BAP receives it.
And BAP transmits the data received from BSC1 to J-AP in 60 to 61 seconds.
If there is no urgent data, data transmission for 40 to 48 seconds and 50 to 58 seconds is not performed.

Further, data transmission is performed as a scheduled transmission frame from the second terminal (BSC2) in area B in 70 to 78 seconds, and the BAP receives the data.
When BSC2 cannot receive ACK from BAP or receives NACK, BSC2 performs data transmission again in 80 to 88 seconds, and BAP receives it.
And BAP transmits the data received from BSC2 to J-AP in 90 to 91 seconds.

[Area C transmission processing]
In area C, data is transmitted as a scheduled transmission frame from the first terminal (CSC1) in area C in 20 to 28 seconds, and the access point (CAP) in area C receives the data.

When ACK is not obtained from CAP or when NACK is received, CSC1 performs data transmission again in 30 to 38 seconds, and CAP receives it.
And CAP transmits the data received from CSC1 to J-AP in 40 to 41 seconds.

If there is urgent data in CSC1, the spontaneous data is transmitted to the CAP as an urgent transmission frame in 50 to 58 seconds. The CAP receives the spontaneous data.
When ACK is not obtained from CAP or when NACK is received, CSC1 performs data transmission again in 60 to 68 seconds, and CAP receives it.
And CAP transmits the data received from CSC1 to J-AP in 70 to 71 seconds.
When there is no urgent data, data transmission for 50 to 58 seconds and 60 to 68 seconds is not performed.

[Effect of transmission timing]
In this way, for each terminal, a scheduled transmission frame and an emergency transmission frame are divided, and for each, a transmission interval is provided when the access point cannot normally receive transmission data such as an ACK not being received. Transmission data and emergency transmission data can be reliably transmitted from the terminal to the access point.

[Application examples of transmission timing]
In addition, when AAP does not receive ACK from a relay station about the data transmitted in 20-21 seconds, or when NACK is received, you may make it resend the said data in 50-51 seconds.
Similarly, when the BAP does not receive ACK from the relay station for data transmitted in 30 to 31 seconds or receives NACK, the BAP may retransmit the data in 60 to 61 seconds.

  In this way, when the data transmitted in the scheduled transmission frame from the terminal is not normally transmitted from the access point to the repeater, the data that has not been transmitted at the timing of transmitting the data of the emergency transmission frame that follows is transmitted to the access point. By transmitting to the repeater, transmission from the access point to the repeater can be performed reliably.

Further, the terminal may transmit the data of the scheduled transmission frame as the data of the emergency transmission frame according to the priority order of the emergency data.
Specifically, emergency data with high priority, for example, status display information indicating the occurrence of an external trigger, can be transmitted in an emergency transmission frame instead of a regular transmission frame.

  As a result, not only the specified emergency transmission frame but also emergency data with high priority can be transmitted as a regular transmission frame as an emergency transmission frame. It can be efficiently transmitted to the data server 43 based on a lot of emergency data.

In the example of FIG. 5, the regular transmission frame and the emergency transmission frame are equally allocated to the terminals in the area. However, the data transmission ratio may be increased depending on the importance of the terminals to which the sensor is connected.
Specifically, in the example of FIG. 5, a scheduled transmission frame and an emergency transmission frame are assigned to one terminal in 60 seconds, and three terminals make a round in 180 seconds, but the first terminal transmits. If the data is important, the first 60 seconds are assigned to the first terminal, the second 60 seconds are assigned to the second terminal, the third 60 seconds are assigned to the first terminal, the fourth May be allocated to the third terminal.
By making such assignment, there is an effect that highly important data can be transmitted with high frequency.

[Confirmation mode during installation: Fig. 6]
Next, a confirmation mode at the time of installation will be described with reference to FIG. FIG. 6 is an explanatory diagram of a confirmation mode at the time of installation.
As shown in FIG. 6, the confirmation mode at the time of installation is used when the area B is constructed. In the district where the repeater 1a is installed, the repeater 1a is set to “installation mode”. An access point 11b is installed at a specific position in area B.
In the installation mode in the repeater 1b, when an installation signal is received from the outside, the control unit returns an ACK signal.

Then, when the access point 11b transmits the installation signal (A), the repeater 1a returns an ACK signal (B) in response to the installation signal (A).
When receiving the ACK signal (b), the access point 11b displays the reception of the ACK signal on the display unit. As a result, the access point 11b is properly installed with respect to the repeater 1a.

Next, the access point 11b is set to “installation mode” and the terminal 12b is installed. This installation mode has the same function as the installation mode of the repeater 1a.
Then, the terminal 12b transmits an installation signal, and the access point 11b returns an ACK signal in response to the installation signal. When the terminal 12b receives the ACK signal, the terminal 12b displays the reception of the ACK signal on the display unit.

In this way, the access point 11b can be properly installed in the range where radio waves reach the repeater 1a, and the terminal 12b can also be properly installed in the range where radio waves reach the access point 11b. .
Note that the communication method from the access point 11b to the relay station 1a and the communication method from the terminal 12b to the access point 11b employ different communication methods.

[Time distribution function]
Since the communication between the access point 11b and the repeater 1a uses a time division method, the time of the clock built in each device needs to be accurate. The same applies to the communication between the terminal 12b and the access point 11b.
Therefore, when installation is performed, the access point 11b transmits a time request signal to the repeater 1a, and the repeater 1a returns time information of the built-in clock to the access point 11b.
The access point 11b adjusts the time of the built-in clock according to the received time information.

Similarly, when installation is performed, the terminal 12b transmits a time request signal to the access point 11b, and the access point 11b returns time information of the built-in clock to the terminal 12b.
The terminal 12b adjusts the time of the built-in clock according to the received time information.

Further, in order to adjust the time lag of the built-in clock, the time information of the built-in clock of the repeater is distributed from the repeater 1a at specific time intervals such as daily or weekly, and the time of the built-in clock at the access point 11b and the terminal 12b is distributed. Adjustments are made.
As a result, the internal clocks of the devices in the area and in the district are aligned, and time division communication can be performed normally.

[Effect of the embodiment]
According to this system, the scheduled transmission frame and the emergency transmission frame are separated to avoid interference in the own system, and further, emergency data is transmitted in the emergency transmission frame instead of the scheduled transmission frame according to the emergency priority. As a result, more emergency data can be efficiently transmitted.

  The present invention is suitable for a wireless communication method and a wireless sensor network system that can quickly and efficiently transmit emergency information while avoiding interference in the system itself.

  DESCRIPTION OF SYMBOLS 1 ... Relay machine, 2 ... Router, 3 ... Internet network, 5 ... ISP server, 6 ... PC, 7 ... Server, such as a mobile operator, 8 ... Mobile terminal, 11 ... Access point, 12 ... Terminal, 41 ... Firewall, 42 ... router, 43 ... data server, 44 ... monitoring terminal, 45 ... SMTP server, 111 ... receiving antenna, 112 ... receiving unit, 113 ... control unit, 114 ... storage unit, 115 ... transmitting unit, 116 ... transmitting antenna

Claims (8)

A wireless communication method in which an access point receives data wirelessly transmitted from a terminal connected to a sensor provided in an area, and transmits the received data from the access point to a repeater by wireless communication,
Each terminal uses the same frequency for each area, and a period for transmitting data is determined in a time-sharing manner, and a scheduled transmission frame for regular data and an emergency transmission frame for emergency data can be transmitted within the period. Yes,
The terminal determines whether it is urgent by comparing the data input from the connected sensor with the threshold stored internally, and if it is not urgent, it transmits the scheduled data using the scheduled transmission frame but also uses the emergency transmission frame If it is urgent, send emergency data with an emergency transmission frame,
If the access point cannot receive the scheduled data transmitted in the scheduled transmission frame from the terminal, the terminal again transmits the scheduled data in the scheduled transmission frame,
When the emergency data transmitted from the terminal in the emergency transmission frame cannot be received by the access point, the terminal again transmits the emergency data in the emergency transmission frame,
The access point transmits the received scheduled data and emergency data to the repeater at different timings, respectively.   When the data input from the sensor is urgently determined, the terminal determines the priority of the emergency, and if the priority is higher than the specific priority, the terminal transmits the emergency data using the emergency transmission frame instead of the scheduled transmission frame. The wireless communication method according to claim 1.   The communication method from the terminal to the access point is the first communication method, the communication method from the access point to the repeater is the second communication method, and the first communication method and the second communication method are different. The first communication method is a communication method that consumes less power than the second communication method, and the second communication method has a longer communication distance than the first communication method. 3. The wireless communication method according to claim 1, wherein a communication method is used. A repeater provided in a district having a plurality of areas; a terminal connected to a sensor provided in the area; and the repeater provided for each area and receiving data wirelessly transmitted from the terminal A wireless sensor network system having an access point for wireless transmission to
The terminal uses the same frequency for each area, and a time period for transmitting data is determined in a time-sharing manner, and data is transmitted in a scheduled transmission frame for scheduled data and an emergency transmission frame for emergency data within the period. It is possible to determine whether or not it is urgent by comparing the data input from the sensor to be connected with a threshold value held internally, and if it is not urgent, it transmits the scheduled data by the scheduled transmission frame, but the emergency transmission Without using a frame, if it is urgent, send emergency data with the emergency transmission frame,
When the access point cannot receive the scheduled data transmitted in the scheduled transmission frame, the terminal transmits the scheduled data again in the scheduled transmission frame, and the emergency data transmitted in the emergency transmission frame is received by the access point. If not, send emergency data again in the emergency transmission frame,
The wireless sensor network system, wherein the access point transmits the received scheduled data and emergency data to the repeater at different timings.   When the data input from the sensor is urgently determined, the terminal determines the priority of the emergency, and if the priority is higher than the specific priority, the terminal transmits the emergency data using the emergency transmission frame instead of the scheduled transmission frame. The wireless sensor network system according to claim 4.   The communication method from the terminal to the access point is the first communication method, the communication method from the access point to the repeater is the second communication method, and the first communication method and the second communication method are different. The first communication method is a communication method that consumes less power than the second communication method, and the second communication method has a longer communication distance than the first communication method. 6. The wireless sensor network system according to claim 4, wherein the wireless sensor network system is a communication system. When installing an access point for a repeater, the access point transmits an installation signal, receives a response signal for the installation signal, displays a response signal reception on the display unit,
The wireless sensor network system according to claim 4, wherein the repeater returns a response signal to the installation signal from the access point. When installing a terminal in an area with respect to the access point, the terminal transmits an installation signal, receives a response signal for the installation signal, and displays a response signal reception on the display unit,
The wireless sensor network system according to claim 7, wherein the access point returns a response signal to the installation signal from the terminal.

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