WO2016046869A1

WO2016046869A1 - Communication quality measurement method and communication system

Info

Publication number: WO2016046869A1
Application number: PCT/JP2014/074987
Authority: WO
Inventors: 中野　亮; 博貴森部; 原田　諭; 達矢副島
Original assignee: 株式会社日立製作所
Priority date: 2014-09-22
Filing date: 2014-09-22
Publication date: 2016-03-31

Abstract

The communication qualities among terminals are measured in detail in a short time at very short time intervals. Further, in a case where there exists a terminal the communication quality for which is desirably measured in an intensive manner, an intensive measurement related to the particular terminal is performed without increasing the communication amount, while the measurements for the other terminals are being maintained. Each of a gateway and a plurality of terminals on a network records, upon reception of radio waves transmitted nearby, information of the transmission source and the communication quality at the time of the reception into its own nearby terminal management table regardless of the communication destination. The gateway designates a communication path and sends a packet for requesting each of the terminals to provide a notification of nearby terminal information, and the terminal having received the request sends back the recorded information of its nearby terminal management table. In a case where there exists a terminal the communication quality for which is desirably measured, when the gateway transmits the request packet to the terminals, the gateway designates a communication path passing through that terminal or communication paths passing through nearby terminals that can directly communicate with that terminal, thereby increasing the number of radio wave receptions by that terminal, thereby performing an intensive measurement.

Description

Communication quality measuring method and communication system

The present invention relates to a method for measuring communication quality between terminals in a communication system.

Along with the spread and diversification of network usage, in the field of sensor networks and the like, many systems have been constructed that accommodate multiple terminals under the gateway and collect data from the terminals using wireless communication. . However, even if a terminal is installed in the field, even if communication is not possible due to radio wave shielding by obstacles, or communication with other terminals is possible, the communication quality is poor and the desired communication requirements can be achieved. There are cases where it is not possible. In such a case, it is necessary to supplement the radio wave coverage and stabilize the communication quality by installing a repeater. Therefore, it is necessary to identify terminals that cannot meet the communication requirements required for the system, such as isolated terminals that are not able to communicate with other terminals and terminals that have only poor quality communication links. A method for measuring the communication quality of the network is required.

Measures communication quality between terminals by instructing a specific terminal to broadcast a measurement packet and inquiring all terminals about the reception result of the packet as a prior art for measuring communication quality between terminals. There exists a technique to perform (Patent Document 1). By instructing each terminal to transmit the measurement packet in turn, and inquiring the reception result of the packet to all terminals each time, the communication quality between the terminals at the time of receiving the measurement packet can be measured. Is possible.

Patent No. 5103324

However, in the method of Patent Document 1, the opportunity to measure the communication quality is limited only to the time of receiving the measurement packet, so that only the instantaneous communication quality at a certain time can be observed. For example, if the communication quality when the measurement packet is received is good even though the communication quality is originally poor and the communication requirement is difficult to achieve, the terminal can achieve the communication requirement. As a result, there is a risk of making an erroneous determination. Since communication quality in wireless communication varies with time, it is desirable to perform measurement capable of following the time variation. For example, even in the method of Patent Document 1, a certain time fluctuation is caused with respect to communication quality by repeating a measurement packet transmission command for the same terminal a plurality of times and inquiring the reception result of the measurement packet to all terminals every time. Can be observed. However, it takes a certain amount of time to instruct a specific terminal to transmit a measurement packet and inquire all the terminals about the reception result of the packet, so it is difficult to follow the communication quality that varies in a short time. .

On the other hand, when a certain number of measurement processes for each terminal were completed, it was determined whether or not the communication requirements of each terminal could be achieved, and in the subsequent measurement processes, it was not possible to sufficiently determine whether or not it could be achieved with the existing measurement results alone It is effective to measure the terminal with priority. As a result, it is possible to reduce the time required to determine whether or not the communication requirements can be achieved for all terminals. However, even if the terminal has already judged whether or not the communication requirements can be met, the communication quality may have been good by chance for a certain period of time. It is desirable to continue.

The present invention has been made in view of the above, and an object thereof is to measure the communication quality between terminals in a short time and in fine time intervals. In addition, when there is a terminal that you want to measure intensively, while maintaining the measurement for other terminals, the number of measurements related to the terminal is efficiently increased, and detailed measurement of communication quality is realized .

In order to solve the above problems, the present invention has the following configuration.

A plurality of terminals connected by a network, and a gateway, wherein the terminal stores a radio wave transmission source and a neighboring terminal management table including communication quality of communication with the transmission source; When the communication is received, the sender and the communication quality at the time of reception are recorded in the neighboring terminal management table as neighboring terminal information, and when the neighboring terminal information transmission request is received, the neighboring terminal management table is referred to, and the requesting source Is realized by a communication system including a neighboring terminal information management unit that transmits neighboring terminal information.

It is possible to measure the communication quality between each terminal in detail at fine time intervals, and it is possible to collect more communication quality information in a short time.

It is an example of the block diagram explaining the structure of the communication system in an Example. It is an example of the hardware block diagram of the terminal in an Example. It is an example of the hardware block diagram of the gateway in an Example. It is an example of the neighborhood terminal management table which the terminal and gateway in an Example hold | maintain. It is an example of the flowchart which shows the whole process in the communication quality measurement in an Example. It is an example of the sequence diagram which shows the neighboring terminal information collection process which concerns on 1st Example in an Example. It is explanatory drawing which shows the operation example of the neighboring terminal information collection process in an Example. It is an example of the flowchart which shows the operation | movement at the time of the packet reception in an Example. It is an example of the flowchart which shows the change process of the designated communication path | route by the gateway in an Example. It is explanatory drawing which shows the example of a change of the communication path in an Example. It is explanatory drawing which shows the example of a display of the communication quality measurement result in an Example. It is an example of the flowchart which shows determination / display processing of the necessity of installation of a repeater in an Example. It is explanatory drawing which shows the example of a display of the repeater installation necessity in an Example. It is an example of the flowchart which shows the communication interruption detection and cause analysis / warning display process in an Example. It is explanatory drawing which shows the warning display example at the time of the communication interruption in an Example. It is an example of the sequence diagram which shows the neighboring terminal information collection process which concerns on 2nd Example in an Example.

First, when measuring the communication quality, each terminal receives the radio wave transmitted by other terminals, and records the radio wave source and the communication quality at the time of reception regardless of whether the communication is addressed to itself. It shall be. Hereinafter, the table used for this recording is referred to as a neighboring terminal management table. Due to the characteristics of wireless communication, when a terminal transmits a packet, the radio wave propagates spatially, so if it is located within the radio wave reachable range, peripheral terminals other than the specified destination can also receive the radio wave. is there. Generally, when a packet is received, the destination is referred to, and if the communication is not addressed to itself, the packet is discarded. At this time, in the present invention, the transmission source information and the communication quality at the time of reception are recorded in the neighboring terminal management table. Process.

Under this condition, the gateway first designates a specific terminal to identify which terminal is in the vicinity of each terminal and how much communication quality each communicates with. Send an information request packet. At this time, the gateway specifies not only the final destination of the neighboring terminal information request packet but also a communication path through which the packet is transferred. When the terminal designated as the final destination receives the neighbor terminal information request packet, the response request packet is transmitted by broadcast. The neighboring terminal that has received the response request packet returns a response packet to the transmission source. When the terminal that transmitted the response request packet receives this response, the transmission source of the response packet and the communication quality at the time of reception are recorded in the neighboring terminal management table.

After that, as the neighboring terminal information, the information of the neighboring terminal management table recorded so far is stored in the neighboring terminal information response packet, and the communication path to be passed is designated and transmitted to the gateway. As described above, it is assumed that the gateway transmits a neighboring terminal information request packet and performs a series of processes for collecting information in the neighboring terminal management table from the terminal for each terminal. In addition, about this series of processing,
(1) Processing for transferring a neighboring terminal information request packet from the gateway to the terminal of the final destination,
(2) Processing for transmitting a response request packet by broadcast,
(3) Processing for returning a response packet to the transmission source of the response request packet;
(4) In the process of transferring the neighboring terminal information response packet from the terminal to the gateway, each terminal has an opportunity to receive the transmission radio waves of other terminals.

At this time, as described above, even when the communication is not addressed to itself, the information at the time of reception is recorded in the neighboring terminal management table, and the recorded information is collectively transmitted when the terminal transmits the neighboring terminal information to the gateway. It shall be. In this way, by recording the reception result every time when the transmission radio waves of other terminals are received, each terminal can record information on communication quality at finer time intervals, and gateways can be recorded more in a short time. Communication quality information can be acquired. Moreover, by displaying the collected communication quality information as necessary, it is possible to visually grasp the communication quality between the terminals.

Then, when the series of processes related to the collection of neighboring terminal information described above is completed for each terminal a predetermined number of times, it is determined whether or not the communication requirement can be achieved for each terminal based on the collected information. As a result, if the communication quality varies greatly over time, or if the communication quality continues to fluctuate within a range close to the criteria for determining whether or not it can be achieved, the existing collection information alone can be used to determine whether the communication requirements can be met. Extract unusable terminals.

The terminal extracted here is the target of priority measurement in the subsequent measurement processing. Thereafter, a series of processes relating to the collection of neighboring terminal information is again performed for each terminal a predetermined number of times. At this time, when transmitting a neighbor terminal information request packet from the gateway to each terminal, as a communication path through which the data is transferred, a communication path that passes through the terminal of the priority measurement target, or a neighbor that can directly communicate with the terminal of the priority measurement target Change to a communication path via the terminal. By changing to such a communication path, it is possible to continue collecting neighboring terminal information for each terminal and increase the number of times the terminal subject to priority measurement receives radio waves in the process. It becomes possible to perform detailed measurement with respect to.

When the collection process is completed a certain number of times for each terminal again, it is determined again whether or not the communication requirement can be achieved. In this way, the process of collecting the neighboring terminal information recorded in the neighboring terminal management table and the judgment process regarding whether or not the communication requirement can be achieved are repeatedly performed, and finally the communication requirement can be achieved for all the terminals. End the quality measurement process.

Embodiments relating to a communication system according to the present invention and communication quality measurement processing will be described below with reference to FIGS. A first embodiment will be described with reference to FIGS. 1 to 15 and a second embodiment will be described with reference to FIG.

Embodiment 1 describes an embodiment that realizes a communication quality measurement process when a communication path that each terminal can use is known in advance. For example, this embodiment corresponds to a case where a communication path between terminals installed in the field is designed in advance and the path information is stored in the terminal in advance at the time of installation.

First, the configuration of the communication system, the terminal, and the gateway will be described with reference to FIGS. Next, the neighboring terminal management table will be described with reference to FIG. Thereafter, the flow of communication quality measurement processing and its operation example will be described with reference to FIGS. Furthermore, display examples regarding communication quality measurement results and processing contents associated with the display will be described with reference to FIGS.

The configuration of the communication system will be described with reference to FIG. In FIG. 1, the communication system 1 includes an application server 100, a gateway 300, and a plurality of terminals 200. Although FIG. 1 shows a case where the gateway 300 is connected to the application server 100 wirelessly or by wire, the functions of the application server 100 are integrated into the gateway 300 without separating the gateway 300 and the application server 100. It doesn't matter. On the other hand, sensor data measured by the terminal 200 is transmitted to the gateway 300 using wireless communication. At this time, if the terminal 200 cannot directly communicate with the gateway 300, the other terminal 200 is relayed to transmit data to the gateway in a bucket relay manner. When the gateway 300 and the application server 100 are connected as shown in FIG. 1, the gateway 300 transfers the data collected from the terminal 200 to the application server 100. In addition, as shown in FIG. 1, a network composed of the gateway 300 and the terminal 200 is referred to as a Field AreaＦＡNetwork (hereinafter referred to as FAN).

Referring to FIG. 2, the hardware configuration of the terminal will be described. The terminal 200 is an embedded device having a communication function with the gateway 300 or another terminal 200.

In FIG. 2, the terminal 200 includes a storage device 201, a central control device 206, a power supply circuit 207, and an RF peripheral circuit 208. The storage device 201 includes a communication processing unit 202, a route management unit 203, a neighboring terminal information management unit 204, and a neighboring terminal management table 205. The communication processing unit 202 implements transmission / reception processing in communication. Specifically, packet analysis processing such as packet assembly processing such as designation of a transmission destination at the time of transmission and determination of whether or not the packet is addressed to the own terminal at the time of reception is performed. The route management unit 203 manages route information in communication within the network.

The neighboring terminal information management unit 204 manages information related to other terminals and gateways that exist in a range where communication with the terminal 200 and information related to communication quality with each communication partner can be performed. And response processing when the neighboring terminal information is requested. The storage device 201 includes, for example, a storage device composed of a read-only semiconductor memory and a storage device composed of a rewritable semiconductor memory element, etc., and includes computer programs and management information for realizing the various processes described above. Stores relevant data.

The central control device 206 executes various computer programs stored in the storage device 201. As a result, various functions of the terminal 200 are realized. The power supply circuit 207 supplies power to the terminal 200. Thereby, the terminal 200 operates. The RF peripheral circuit 208 mutually converts a digital signal and a radio signal, converts the generated digital data into a radio signal and transmits it to another terminal or gateway, and a radio signal received from the other terminal or gateway. Consists of a receiver that extracts digital data. Note that the terminal 200 may be an independent device instead of an embedded device.

Referring to FIG. 3, the hardware configuration of the gateway will be described. The hardware configuration of the gateway 300 is that the external network connection circuit 312 and the output unit 313 are mounted, and the storage device 301 includes a path calculation unit 306, a repeater necessity determination unit 307, and a failure detection / analysis unit 308. The configuration is the same as that of the terminal 200.

The gateway 300 communicates with the terminal 200 and the application server 100, collects data from the terminal 200, manages neighboring terminal information related to the terminal 200, and the like. The external network connection circuit 312 is a function for using an external network such as Ethernet (registered trademark), WiFi (registered trademark), an optical line, and a telephone network. However, when the gateway 300 assumes the function of the application server 100, the external network connection circuit 312 is not necessarily installed. The output unit 313 is a function for outputting a communication quality measurement result and the like. The output screen may be mounted on the gateway 300 or externally connected. On the other hand, when the gateway 300 is connected to the application server 100, the output data may be transferred to the application server 100 and displayed on the server side or on a mobile terminal that can access the server.

The neighboring terminal information management unit 304 of the gateway 300 manages and stores not only information about the terminals 200 that can communicate with the gateway 300 but also neighboring terminal information collected from all the terminals 200 existing in the FAN. To do.

Also, the neighboring terminal information management unit 304 performs a request for neighboring terminal information to the terminal 200 and a determination process for determining whether or not communication requirements can be achieved based on the collected information. On the other hand, the route calculation unit 306 provided in the storage device 301 performs a process of calculating a communication route from the gateway 300 to the specific terminal 200 based on the neighboring terminal information collected from the terminal 200 in the FAN. The repeater necessity determination unit 307 performs processing for determining whether or not it is necessary to install a repeater for each terminal 200 based on the collected neighboring terminal information. The failure detection / analysis unit 308 performs communication failure detection and failure cause analysis processing based on the collected neighboring terminal information.

The neighboring terminal management tables 205 and 305 held by the terminal and the gateway will be described with reference to FIG. The neighboring terminal management table shown in FIG. 4 is managed by the neighboring terminal

information management units

204 and 304 of the terminals and gateways that hold the table, and relates to terminals and gateways that can communicate with themselves among the terminals and gateways existing in the FAN. Information and the communication quality with each communication partner are managed. ID 401 in FIG. 4 indicates an identifier of a terminal and a gateway that can communicate with itself.

Specifically, it is a field that describes the addresses and host names of terminals and gateways. The identifier described in this field conforms to the method adopted in the communication system. If the terminal or gateway is identified by an IP address, a MAC address or a unique identifier, those identifiers may be described. RSSI (1) 402 and RSSI (2) 403 indicate received radio wave strengths (hereinafter referred to as RSSI (Received Signal Signal Strength Indicator)) when receiving radio waves from the terminal or gateway described in ID 401.

The RSSI when the radio wave is received for the first time is recorded in RSSI (1) 402, and the RSSI when the radio wave is received for the second time is recorded in RSSI (2) 403. Although not shown in FIG. 4, the neighboring terminal management tables 205 and 305 for terminals and gateways are provided with a field for recording RSSI for any N times according to the storage area capacity of the terminals and gateways. Good. When all the N fields have been described, the old information is deleted in order, and a new RSSI is recorded. If the terminal or gateway manages time information, the time when RSSI is recorded may be managed by the neighboring terminal management tables 205 and 305. Further, statistical information such as the average value, the maximum value, and the minimum value of RSSI observed in the past may be managed by the neighboring terminal management tables 205 and 305. In FIG. 4, RSSI is taken as an example of an index indicating communication quality. However, when information such as a packet loss rate is managed as an index of communication quality, these are similarly used for the neighboring terminal management table 205 and You may manage by 305.

Referring to FIG. 5, the overall processing flow in communication quality measurement performed by the gateway will be described. In measuring the communication quality between the terminals, the information of the neighboring terminal management table 205 held by each terminal is collected as neighboring terminal information according to the process of FIG. Thereafter, based on the collected neighboring terminal information, it is determined whether or not the communication requirement can be achieved for each terminal.

In FIG. 5, step S501 is a process of specifying a terminal existing in the FAN by the neighboring terminal information management unit 304 of the gateway and collecting neighboring terminal information from the designated terminal. Details of the neighboring terminal information collection processing in step S501 will be described later with reference to FIG. By collecting information in the neighboring terminal management table 205 held by each terminal as neighboring terminal information, it is possible to grasp the neighboring terminals with which each terminal can communicate and the respective communication quality. At this time, the neighboring terminal information management unit 304 of the gateway counts the number of times that the collection process is performed on each terminal. When the process of step S501 ends, the process proceeds to step S502.

Step S502 is processing for determining whether or not the neighboring terminal information collection processing in step S501 has been performed for each terminal a predetermined number of times in the neighboring terminal information management unit 304 of the gateway. If the predetermined number of processes have been performed for each terminal (YES), the process proceeds to step S503. If the process has not reached the predetermined number (NO), the process returns to step S501 and the neighboring terminal information collection process is continued.

Step S503 is a process of determining whether or not each terminal can achieve the communication requirements required of the system by the neighboring terminal information management unit 304 of the gateway based on the collected neighboring terminal information. The criterion for determining whether or not the communication requirement can be achieved may be set according to an application operating in the communication system. For example, when RSSI recorded in the neighboring terminal management tables 205 and 305 of the terminal and the gateway is used as an index, RSSI that is equal to or higher than the threshold value X is observed among RSSIs observed between neighboring terminals on the communication path. If the number of times exceeds a certain ratio, it can be determined that sufficiently good communication quality is obtained and the terminal determines that the communication requirement can be achieved.

On the other hand, if the number of times RSSI less than or equal to the threshold Y is observed exceeds a certain ratio, it is determined that the communication quality is poor, and the terminal can determine that the communication requirement cannot be achieved. If neither condition is met, it is determined that it is not possible to determine whether or not the communication requirement can be achieved by using only the information collected at the present time, and the terminal is selected as a priority measurement target terminal in the subsequent processing. Here, the example of the determination standard using RSSI as an index has been described. However, in an application operating in a communication system, when other indexes such as a packet loss rate are emphasized, these indexes are used to determine whether or not communication requirements can be achieved. You may set suitably the adopted criterion.

In addition to statically defining this standard in advance, this standard holds various threshold values that serve as the standard as variable parameters, and a user can appropriately select the standard on a screen that displays the measurement results of communication quality described later. It may be dynamically defined. When the determination process regarding whether or not the communication requirement is achieved is completed, the process proceeds to step S504.

In step S504, based on the determination result in step S503, the neighboring terminal information management unit 304 of the gateway determines whether or not there is a terminal that has not been able to determine whether or not the communication requirement can be achieved only with the existing collection information. It is processing. If there is a terminal that has not been able to determine whether or not the communication requirement can be achieved (YES), additional information regarding the communication quality is required, and thus the process proceeds to step 505. On the other hand, when it is possible to determine whether or not the communication requirements can be achieved for all terminals (NO), the processing of the flowchart shown in FIG.

Step S505 is a process of changing the communication path designated by the gateway in the subsequent neighboring terminal information collection process in the gateway path calculation unit 306. Specifically, the communication path is changed to a communication path that passes through the terminal of the priority measurement target for which it was not possible to determine whether or not the communication requirement can be achieved in step S503, or to a communication path that passes through a neighboring terminal that can directly communicate with the terminal. Details of this processing will be described later with reference to FIG. 9, and a specific example will be described later with reference to FIG. When this process ends, the process proceeds to step S506.

Step S506 is a process of resetting the number of executions of the process counted by the neighboring terminal information management unit 304 of the gateway in order to perform the neighboring terminal information collecting process for each terminal again a predetermined number of times. When this process ends, the process returns to step S501 to restart the neighboring terminal information collection process for each terminal. In addition, when performing the neighboring terminal information collection process a predetermined number of times for each terminal again, the number of times of performing this collection process does not necessarily have to be uniform for each terminal, for example, a terminal that has been able to determine whether or not communication requirements can be achieved As for, the number of times may be reduced. However, it is desirable to continue the collection process at a certain frequency even if the terminal has already judged whether or not the communication requirements can be met, because the communication quality may have been good or poor for a certain period of time. .

With reference to FIG. 6, the flow of the neighboring terminal information collection process performed in step S501 of FIG. 5 will be described. When the gateway collects information of the neighboring terminal management table 205 held by each terminal as neighboring terminal information, the processing of FIG. 6 is performed.

Step S601 is processing in which the gateway selects a terminal from which the neighboring terminal information is to be collected by the neighboring terminal information management unit 304 and transmits a neighboring terminal information request packet to the terminal. The neighboring terminal information request packet is a packet that requests a specified terminal to transmit information of the neighboring terminal management table 205 held by the terminal. At this time, in addition to setting the final destination of the packet to the collection target terminal, the gateway also specifies a transfer path from the gateway to the target terminal. Before performing the determination process regarding whether or not the communication requirement can be achieved in step S503 in FIG. 5, a default communication route recorded in advance in the route management unit 303 of the gateway is designated.

On the other hand, after the determination process in step S503 is performed, the communication path changed in step S505 in FIG. 5 is designated. Information on the designated communication path is stored in the neighboring terminal information request packet. This is because the relay terminal of the packet can grasp the next transfer destination. The packet assembly process is performed by the gateway communication processing unit 302 as described above.

In step S602, when the relay terminal on the transfer route receives the neighboring terminal information request packet, the communication processing unit 202 of the terminal refers to the route information stored in the packet, and sends the neighboring terminal information to the next forwarding destination. This is a process for transferring a request packet. Specifically, the communication processing unit 202 of the terminal rewrites the destination of the neighboring terminal information request packet to the information of the next transfer destination and performs transmission.

In step S603, the terminal specified as the final destination of the neighboring terminal information request packet receives the packet, the communication processing unit 202 of the terminal refers to the final destination of the packet, and the local terminal is notified of the neighboring terminal information. It is a process to confirm that it is requested. At this time, the communication processing unit 202 of the terminal notifies the neighboring terminal information management unit 204 that neighboring terminal information is requested.

Step S604 is a process in which the neighboring terminal information management unit 204 receives a notification that the neighboring terminal information is requested and transmits a response request packet by broadcast. The response request packet is a packet that requests a terminal that has received the packet to return a response packet.

In step S605, a response request packet broadcast by a terminal located around the transmission source terminal of the response request packet is received, the communication processing unit 202 analyzes the packet, and requests a response from the neighboring terminal information management unit 204 This is a process of notifying that it has been performed.

Step S606 is a process of receiving a notification that the neighboring terminal information management unit 204 is requesting a response and transmitting a response packet to the request source. The response packet is a packet that responds to the request source that the response request packet has been received. Since the response request packet is transmitted by broadcast, radio interference may occur when a plurality of terminals receive the response request packet and each terminal transmits the response packet at the same time. Therefore, processing such as insertion of random time jitter may be added before transmission of a response packet as necessary.

In step S607, the terminal that transmitted the response request packet in step S604 receives a response packet from a neighboring terminal located in the vicinity, analyzes the packet by the communication processing unit 202, and sends a response to the neighboring terminal information management unit 204. This is a process for notifying that it has been received. Note that the processing related to transmission / reception of the response request packet and response packet in steps S604 to S607 in FIG. 6 is not essential, and may be performed a plurality of times. The number of times may be set arbitrarily. When the number is set to a small number, the time required for the neighboring terminal information collection process can be shortened. On the other hand, when the number of times is increased, it is possible to detect terminals existing in the vicinity with high accuracy.

In step S608, the terminal that has received the neighboring terminal information request packet in step S603 refers to the information in the neighboring terminal management table 205 in the neighboring terminal management information management unit 204, and transmits the neighboring terminal information response packet to the gateway. It is processing. The neighboring terminal information response packet is a packet for notifying the gateway of the neighboring terminal information of the own terminal, and stores information of the neighboring terminal management table 205 held by the own terminal as the neighboring terminal information. The neighboring terminal information management unit 204 notifies the communication processing unit 202 of information in the neighboring terminal management table 205 held by the own terminal, and assembles a neighboring terminal information response packet storing the information. Note that it is not always necessary to store the information of all fields in the neighboring terminal management table 205. If neighboring terminal information has been transmitted to the gateway at least once in the past, only the portion that has been added or updated since the previous transmission is used. It may be selected and stored in the neighboring terminal information response packet.

At the time of transmission, a gateway is set as the final destination of the neighboring terminal information response packet, and a path opposite to the communication path specified by the neighboring terminal information request packet is designated as the transfer path of the packet. Since the information on the communication path designated by the gateway is stored in the neighboring terminal information request packet, even if the designated communication path is changed in step S505 in FIG. It is possible to grasp the designated communication path.

In step S609, when the relay terminal on the transfer path specified in step S608 receives the neighboring terminal information response packet, the communication processing unit 202 of the terminal refers to the path information stored in the packet. This is a process of transferring the neighboring terminal information response packet to the transfer destination. Specifically, the communication processing unit 202 of the terminal rewrites the destination of the neighboring terminal information response packet to the information of the next transfer destination and performs transmission.

Step S610 is a process in which the gateway receives the neighboring terminal information response packet, analyzes the packet by the communication processing unit 302, and notifies the neighboring terminal information management unit 304 that the neighboring terminal information has been received from the terminal. It is.

In step S611, in response to the notification that the neighboring terminal information management unit 304 has received the neighboring terminal information, the neighboring terminal information stored in the neighboring terminal information response packet is recorded as the neighboring terminal information of the terminal specified in step S601. It is processing.

When this process is finished, the neighboring terminal information collection process of FIG. 6 is finished.

Note that when the communication path designated by the gateway is changed in step S505 in FIG. 5, a path with good communication quality is not necessarily selected. Along with this, there may occur a case in which packet loss occurs between the gateway requesting the neighboring terminal information from the specific terminal and receiving a response, and the collection of the neighboring terminal information fails.

Therefore, if a response is not obtained even after a lapse of a certain time after the gateway transmits the neighbor terminal information request packet, retransmission processing may be performed as appropriate. Further, when the neighboring terminal information collection process cannot be executed due to packet loss in the communication path changed in step S505, the retransmission process may be performed by re-designating the communication path before the change.

In the processing of FIG. 6, in the transmission of the neighboring terminal information request packet, the transmission of the response request packet, the transmission of the response packet, and the transmission of the neighboring terminal information response packet, various types of terminals and gateways are used regardless of whether the communication is addressed to itself. An opportunity to receive the packet is obtained. At this time, as described above, the terminal and the gateway record the information on the transmission source and the communication quality at the time of reception in the neighboring terminal management tables 205 and 305 that are held respectively. The operation at the time of reception will be described later with reference to FIG.

Referring to FIG. 7, an example of operation of neighboring terminal information collection processing will be described. FIG. 7 shows an example of collecting neighboring terminal information from the terminal 200-C. In FIG. 7, the reachable range of the transmission radio wave by the terminal 200 and the gateway 300 is indicated by a dotted line, and is indicated as the radio wave

reachable areas

201 and 301. The radio wave transmission source is the terminal 200 or the gateway 300 located at the center of the radio wave reachable range.

FIG. 7A shows a state in which the neighboring terminal information request packet is transmitted from the gateway 300 to the final destination terminal 200-C in steps S601 and S602 of FIG. At this time, the gateway 300 designates a communication path of gateway 300 → terminal 200-A → terminal 200-C as a transit path in the transfer. When the gateway 300 transmits to the terminal 200-A, the terminal 200-B is included in the radio wave reachable range 301, and the terminal 200-B receives the transmission radio wave of the gateway 300 although it is not designated as a destination. Things are possible.

Similarly, when the terminal 200-A transmits to the terminal 200-C, the gateway 300 and the terminal 200-D are included in the radio wave reachable range 201-A, and receive the radio waves transmitted from the terminal 200-A. Is possible. As long as it is within the radio wave reachable range, it is possible to receive radio waves even if the communication is not addressed to itself. Therefore, according to the reception process described later in FIG. Record the reception results in the tables 205 and 305.

FIG. 7B shows a state in which the terminal 200-C that has received the neighboring terminal information request packet transmits a response request packet by broadcast in step S604. In the example of FIG. 7B, the response request packet transmitted by the terminal 200-C is received by the three terminals 200-A, 200-D, and 200-F. Each of these terminals also records the reception result in the neighboring terminal management table 205 held by itself when receiving the response request packet.

FIG. 7C shows a state where the terminal that has received the response request packet transmits the response packet to the terminal 200-C that is the response request source in step S606. The terminal 200-C that received the response records the reception result in the neighboring terminal management table 205 of the own terminal. Since the terminal 200-A, the terminal 200-D, and the terminal 200-F transmit the response packet, the terminal 200-G and the gateway 300 existing within the radio wave reach range also receive the radio wave. Are recorded in the neighboring terminal management tables 205 and 305 held by.

FIG. 7 (d) shows a state in which the neighboring terminal information response packet is transmitted from the terminal 200-C to the gateway 300 in steps S608 and 609 in FIG. Since the neighboring terminal information request packet has been transferred through the communication path of gateway 300 → terminal 200-A → terminal 200-C, terminal 200-C has terminal 200-C → terminal 200-A → gateway in the opposite direction to the communication path. A communication path of 300 is designated. When the terminal 200-C and the terminal 200-A transmit the neighboring terminal information response packet, the terminal 200-D and the terminal 200-F existing within the radio wave coverage also receive the transmission radio wave. Record in the neighboring terminal management table 205 held by the terminal. As described above, the gateway can collect the neighboring terminal information from the terminal 200-C through the communication shown in FIGS. 7 (a) to (d). Also, recording of the terminal and gateway in the neighboring terminal management tables 205 and 305 is performed with the reception of the packet generated in the process.

With reference to FIG. 8, the operation at the time of packet reception in the neighboring terminal

information management units

204 and 304 of the terminal and the gateway will be described. When the terminal receives the packet, the reception result is recorded in the neighboring terminal management table 205 held by the terminal regardless of whether or not the packet is addressed to the terminal according to the processing of FIG. The same applies to the gateway. When a packet is received, the reception result is recorded in the neighboring terminal management table 305 held by itself according to the processing of FIG. Here, assuming the reception of a packet by the terminal, the flowchart of FIG. 8 will be described.

Step S801 is a process indicating reception of a packet transmitted by a gateway or another terminal. If it is confirmed that the packet is received from the RF peripheral circuit 208, the process proceeds to step S802.

Step S802 is processing for determining whether or not the information about the transmission source of the received packet has been recorded in the neighboring terminal management table 205 held by the own terminal in the neighboring terminal information management unit 204. As described above, the contents of the packet such as the transmission source information of the received packet are analyzed by the communication processing unit 202. If the sender information has been recorded in the ID column of the neighboring terminal management table 205 held by the terminal itself (YES), the process proceeds to step S804. If not recorded (NO), the process proceeds to step 803.

Step S803 is processing in which the neighboring terminal information management unit 204 adds the transmission source information of the received packet to the neighboring terminal management table 205 held by the own terminal. When the sender ID is recorded in the ID column of the neighboring terminal management table 205, the process proceeds to step S804.

Step S804 is processing in which the neighboring terminal information management unit 204 records the RSSI at the time of packet reception in the RSSI entry column corresponding to the transmission source of the neighboring terminal management table 205 held by the own terminal. If communication quality information other than RSSI is also managed on the table, recording may be performed as appropriate in this processing. When this process ends, the process proceeds to step S805.

Step S805 is processing for performing a predetermined operation according to the contents of the received packet. Specifically, the final destination information of the packet analyzed by the communication processing unit 202 is referred to. When the final destination is set to the broadcast address or the own terminal, an operation according to the type of the packet is performed. For example, when the received packet is a response request packet, a predetermined process such as returning a response packet is executed. On the other hand, if the destination of the packet is set to the own terminal, but the terminal is not set to the final destination, the packet must be transferred to the next transfer destination, so the specified communication path stored in the packet And rewrite the destination to the next transfer destination. If the packet destination is not set to the terminal itself, the received packet is discarded. When this process ends, the flowchart of FIG. 8 ends.

Referring to FIG. 9, the designated communication path changing process in step S505 in FIG. 5 performed by the gateway path calculation unit 306 will be described. In order to perform intensive measurement for the terminal that has not been determined whether or not the communication requirement can be achieved in step S503 in FIG. 5, the gateway executes the designated communication path change process in the path calculation unit 306 according to the process in FIG. 9. Specifically, while referring to neighboring terminal information collected from each terminal, the route calculation unit 306 calculates a possible communication route for delivering a packet from the gateway to each terminal, and there is a communication route suitable for the change. In this case, the changed communication path information is added to the path management unit 303.

By performing the designated communication path changing process of FIG. 9, in the process of transmitting the neighboring terminal information request packet from the gateway to the terminal and the process of transmitting the neighboring terminal information response packet from the terminal to the gateway, the terminal subject to priority measurement It is possible to obtain more reception opportunities and to record more information on communication quality in a short time.

Step S901 is processing in which the route calculation unit 306 selects a terminal as a final destination from terminals existing in the FAN. When this process ends, the process proceeds to step S902.

In step S902, among the communication paths that can be used to deliver a packet from the gateway to the final destination terminal in the path calculation unit 306, a terminal that is a priority measurement target, that is, a terminal that has not yet been determined whether or not the communication requirement can be achieved is used. This is a process for determining whether or not there is a route through. If at least one of the routes exists (YES), the process proceeds to step S903, and if not (NO), the process proceeds to step S904. The route calculation unit 306 calculates a communication route that can be used to deliver a packet from the gateway to the final destination terminal based on the neighboring terminal information collected from each terminal managed by the neighboring terminal information management unit 304 of the gateway. I can do it.

For example, referring to neighboring terminal information collected in the past from the final destination terminal in step S901, a terminal that can communicate with the terminal is extracted. Specifically, the terminal described in the ID column of the neighboring terminal management table 205 held by the terminal is applicable. When this terminal is the terminal a, referring to the neighboring terminal information collected from the terminal a, next, a terminal that can communicate with the terminal a is extracted. In this way, it is possible to search for a terminal that can communicate with the final destination terminal as a starting point, and calculate a communication path from the gateway to the final destination terminal when the finally communicable partner becomes a gateway. It becomes possible.

In step S903, the route calculation unit 306 changes the communication route specified when collecting neighboring terminal information from the final destination terminal in step S901 to a route that passes through a terminal that has not yet been determined whether the communication requirement can be achieved. It is. Specifically, the changed communication route information calculated by the route calculation unit 306 is added to the route management unit 303. At this time, there may be a case where there are a plurality of corresponding routes. In this case, one route is selected. For example, a method of selecting a route that passes through more undetermined terminals is conceivable. Further, in order to avoid loss of the neighboring terminal information request packet and the neighboring terminal information response packet, a method of excluding a communication path including a poor quality communication link is also conceivable. The selection criterion for the communication path is not limited to a specific method, and may be selected according to an arbitrary criterion. When this process ends, the process proceeds to step S906.

In step S904, among the communication paths that can be used by the path calculation unit 306 to deliver the packet from the gateway to the final destination terminal, there is a path that passes through a neighboring terminal that can directly communicate with a terminal that has not yet been determined whether the communication requirements can be achieved. This is a process for determining whether or not it exists. If there is at least one route (YES), the process proceeds to step 905. If it does not exist (NO), the process proceeds to step S906 without changing the communication path for the final destination terminal selected in step S901. In FIG. 9, the process proceeds to step S904 after the determination process in step S902. However, the order of both steps may be reversed.

In step S905, the route calculation unit 306 passes the communication route specified when collecting the neighboring terminal information from the final destination terminal in step S901 via a neighboring terminal that can directly communicate with a terminal that has not yet been determined whether the communication requirements can be achieved. It is processing to change to the route to be. A case where a plurality of corresponding routes exist is also assumed. In this case, one route is selected as in step S903. When this process ends, the process proceeds to step S906.

Step S906 is processing for determining whether or not the route calculation unit 306 has performed the change processing of the designated communication route with all terminals existing in the FAN as final destination terminals. When all terminals have been selected as final destinations (YES), the designated communication path changing process of FIG. 9 is terminated, and when there are terminals that have not yet been selected as final destinations (NO), the process returns to step S901. Is selected as the final destination.

Referring to FIG. 10, an example of changing the communication path specified in the neighboring terminal information collection process will be described. FIG. 10 shows a communication path when the final destination is designated to the terminal 200-F. FIG. 10 (a) shows the communication path before execution of the designated communication path change process, and FIG. 10 (b) shows the communication path after execution. Show. At this time, it is assumed that the terminal 200-G has unstable communication quality and has not yet been able to determine whether or not the communication requirement can be achieved.

In FIG. 10A before changing the designated communication path, a communication path of gateway 300 → terminal 200-A → terminal 200-C → terminal 200-F is used as a path from the gateway to terminal 200-F. Yes. However, even if a packet is transmitted through this communication path, the terminal 200-G is not included in any radio wave arrival range, and the terminal 200-G cannot receive the packet even once. That is, in the process of collecting the neighboring terminal information from the terminal 200-F, it is impossible to perform the measurement related to the terminal 200-G that should be preferentially measured.

Therefore, it is possible to change to the communication path as shown in FIG. 10B, for example, by performing the designated communication path change process of FIG. In FIG. 10B, a communication path of gateway 300 → terminal 200-A → terminal 200-D → terminal 200-F is used. Here, the communication path is changed to the communication path via the terminal 200-D that can directly communicate with the terminal 200-G, and the terminal 200-G can receive the radio wave transmitted by the terminal 200-D. In the process of collecting neighboring terminal information from F, it is possible to simultaneously measure the terminal 200-G. In addition to the communication path shown in FIG. 10B, for example, when the terminal 200-G and the terminal 200-F can communicate directly, the gateway 300 → the terminal 200-A → the terminal 200-D → the terminal 200 The communication path may be changed to pass through the terminal 200-G, such as −G → terminal 200-F.

Referring to FIG. 11, a display example of the communication quality measurement result output via the gateway output unit 313 will be described. As shown in FIG. 11, based on the neighboring terminal information collected from each terminal, the communication quality between the terminals is displayed on the screen via the gateway output unit 313, thereby visually grasping the communication quality in the FAN. Things will be possible.

First, the display example 1101 is an example in which the communication quality of the gateway and each terminal existing in the FAN is collectively displayed. By referring to neighboring terminal information collected from each terminal, it is possible to grasp from which transmission source each terminal has received a packet with what communication quality. Therefore, the communication quality of each link can be displayed as shown in display example 1101 by notifying the output unit 313 of the neighboring terminal information managed by the neighboring terminal information management unit 304 of the gateway.

Also, neighboring terminal information cannot be collected from a specific terminal, and a record of receiving a packet from the terminal is not described in any of the neighboring terminal information collected from other terminals, that is, each terminal holds If no information of the terminal is recorded in any of the neighboring terminal management tables 205, communication quality cannot be displayed as “E” (terminal 200-E) in the display example 1101, and communication is impossible. It is possible to visually grasp that it is an isolated terminal.

In the display example 1101, the start point of the arrow is the transmission source, the end point of the arrow is the reception source, and the RSSI is displayed in three levels. The RSSI to be displayed may be arbitrarily set such as the latest value, the average value, the maximum value, or the minimum value observed in the past. It is not always necessary to display the RSSI divided into levels, and a specific numerical value may be displayed. In addition, the display content is updated at an arbitrary timing such as when the neighboring terminal information of each terminal managed by the gateway is managed by the neighboring terminal information management unit 304 or when the user instructs updating. It doesn't matter.

Subsequently, a display example 1102 is an example in which a change transition related to communication quality in a specific section is displayed. A display example 1102 displays the RSSI fluctuation transition when “Node A” (terminal 200-A) receives from “Node-C” (terminal 200-C). In this case, by referring to the RSSI record related to the terminal 200-C among the neighboring terminal information collected from the terminal 200-A, a display like the display example 1102 can be performed. By making it possible for the user to specify the transmission source and the reception source on the screen, it is possible to grasp the change in the communication quality in an arbitrary section that could not be expressed by the display example 1101 alone. In the display example 1102, the change transition of the communication quality is displayed in a graph format, but a table format or the like may be used. Note that, in the display examples 1101 and 1102, when communication quality information other than RSSI is managed by the terminal and gateway neighboring terminal management tables 205 and 305, these information may be displayed in the same manner.

Referring to FIG. 12, a description will be given of the determination / display processing of whether or not each terminal needs to install a repeater, which is performed by the repeater necessity determination unit 307 of the gateway. By performing the processing of FIG. 12, it is possible to visually confirm to which terminal it is necessary to install the repeater, and it is also possible to grasp the priority regarding the repeater installation. When the number of repeaters that can be prepared is limited, more efficient installation can be realized by installing repeaters in order from the terminal with the highest priority. In the processing of FIG. 12, based on the neighboring terminal information collected from each terminal, the relay repeater necessity determination unit 307 of the gateway determines the necessity of installing a repeater for each terminal and the priority, and finally outputs it. The determination result is output via the unit 313.

Step S1201 is a process in which the repeater necessity determination unit 307 selects one terminal to be determined whether a repeater is necessary from among terminals existing in the FAN. When this process ends, the process proceeds to step S1202.

In step S1202, the repeater necessity determination unit 307 refers to the neighboring terminal information of each terminal managed by the neighboring terminal information management unit 304, and the information on the terminal selected in step S1201 is described as neighboring terminal information. This is a process for determining whether or not there is any. Here, if there is no description about the terminal in the neighboring terminal information of all terminals (YES), the process proceeds to step S1203, and if there is a description (NO), the process proceeds to step S1204.

Step S1203 is a process in which the repeater necessity determination unit 307 determines that the selected terminal in step S1201 is a terminal in which repeater installation is indispensable, that is, a terminal having a high priority of repeater installation. If the information about the terminal is not described in all of the neighboring terminal information collected from the terminal, that is, if it is not recorded in any of the neighboring terminal management tables 205 held by each terminal, the terminal is an isolated terminal. Therefore, it can be determined that the installation of a repeater is essential. When this process ends, the process proceeds to step S1207.

In step S1204, the repeater necessity determination unit 307 refers to the neighboring terminal information of each terminal managed by the neighboring terminal information management unit 304, and the communication quality when the packet is received from the terminal selected in step S1201. This is a process for determining whether or not RSSI is below the threshold value. About this threshold value, you may set to arbitrary values according to the communication requirements etc. which are calculated | required by the system. If both are below the threshold (YES), the process proceeds to step S1205, and if there is an RSSI exceeding the threshold (NO), the process proceeds to step S1206. If communication quality other than RSSI is also emphasized as a communication requirement, these may be appropriately adopted as determination criteria.

Step S1205 is processing in which the repeater necessity determination unit 307 determines that the selected terminal in step S1201 is a terminal in which repeater installation is desirable, that is, a low-priority terminal. Since there are other terminals that can communicate with the terminal, it is not always necessary to install a repeater, but it is not possible to communicate with sufficiently good communication quality, so it is desirable to improve communication quality by installing a repeater Can be judged. When this process ends, the process proceeds to step S1207.

Step S1206 is processing in which the repeater necessity determination unit 307 determines that the selected terminal in step S1201 is a terminal that does not require installation of a repeater. Since there is another terminal capable of communicating with good communication quality exceeding the threshold set in step S1204, it can be determined that no repeater installation is necessary. When this process ends, the process proceeds to step S1207.

Step S1207 is a process of determining whether or not the repeater necessity determination unit 307 has determined whether or not the repeater is necessary for all terminals. If the determination for all terminals has been completed (YES), the process proceeds to step S1208. If not yet completed (NO), the process returns to step S1201, and another terminal is selected again to determine whether a repeater is required. Continue.

Step S1208 is processing for notifying the necessity of installing a repeater of each terminal and the determination result of the priority from the repeater necessity determination unit 307 to the output unit 313 and outputting the result. A specific display example will be described with reference to FIG. When this process ends, the determination / display process for determining whether or not the repeater is installed in FIG. 12 ends.

Referring to FIG. 13, an example of display regarding whether or not a repeater is required for each terminal to be output via the gateway output unit 313 will be described.

In FIG. 13, the display example 1101 of FIG. 11 is applied via the output unit 313 of the gateway to display terminals determined to have repeater installation essential (high priority) or desirable to install repeaters (low priority). It is carried out. First, since “E” (terminal 200-E) is an isolated terminal that cannot communicate with other terminals, it is determined in step S1203 in FIG. Therefore, the fact that the priority for installing the repeater is high is displayed on the screen.

On the other hand, when the RSSI threshold value in the determination of step S1204 in FIG. 12 is set to “−75 dBm”, “G” (terminal 200-G) has not obtained communication quality exceeding the threshold value with any terminal capable of communication. . In this case, since it is determined in step S1205 of FIG. 12 that the repeater installation is desirable, the fact that the priority of the repeater installation is low is displayed on the screen. On the other hand, the terminal that does not display the priority in FIG. 13 is a terminal that has been determined that the repeater installation is unnecessary in step S1206 of FIG. By performing the display as shown in FIG. 13, the user can visually confirm to which terminal the repeater should be installed based on the measurement result of the communication quality. However, the display method of FIG. 13 is an example, and is not necessarily limited to the format of FIG.

Referring to FIG. 14, communication failure detection and cause analysis and warning display processing performed by the gateway failure detection / analysis unit 308 will be described. In the process of collecting neighboring terminal information from each terminal, there is a possibility that communication disruption may occur due to a terminal failure or an obstacle that shields radio waves. Therefore, by periodically performing the processing of FIG. 14 and confirming the presence or absence of communication interruption and displaying the result as appropriate, it is possible to visually confirm the occurrence of the communication interruption and the cause thereof. Note that the cycle and timing for executing the processing of FIG. 14 may be arbitrarily set. In the processing of FIG. 14, the failure detection / analysis unit 308 of the gateway detects communication interruption and analyzes the cause based on the neighboring terminal information collected from each terminal, and finally the analysis result via the output unit 313. Output warnings according to.

In step S1401, the failure detection / analysis unit 308 refers to the neighboring terminal information of each terminal managed by the neighboring terminal information management unit 304, and the reception record from a certain neighboring terminal has been continuously interrupted for a certain period of time. Is a process for determining whether or not there exists. About this period, you may set arbitrarily, for example, by setting a short period, it becomes possible to detect communication interruption at an early stage. However, even if packet loss occurs continuously by accident, there is a risk of erroneous detection of communication interruption, so it is desirable to detect it for a certain period of time. If there is a terminal whose reception record from a specific terminal has been continuously interrupted for a certain period (YES), the process proceeds to step S1402, and if there is no corresponding terminal (NO), it is determined that the terminal is in a normal state. This flowchart is finished.

In step S1402, in the failure detection / analysis unit 308, the neighborhood terminal managed by the neighboring terminal information management unit 304 for all terminals that have received reception records in the past from the same transmission source terminal in which the reception record was interrupted in step S1401. This process refers to terminal information and determines whether or not reception recording is interrupted in any terminal. In any case, if reception recording is interrupted (YES), the process proceeds to step S1403, and if reception recording is continued in at least one terminal (NO), the process proceeds to step S1404.

Step S1403 is a process in which the failure detection / analysis unit 308 determines that the failure of the terminal is the cause of communication interruption, notifies the output unit 313 of the determination result, and outputs a warning that a terminal failure has occurred. is there. If the reception record from the terminal is uniformly interrupted regardless of the terminal, it is suspected that the communication function of the terminal is stopped, so that it can be estimated that the terminal is due to failure. When this process ends, the flowchart of FIG. 14 ends.

In step S1404, the failure detection / analysis unit 308 determines that the occurrence of the obstacle on the transmission path is the cause of the communication interruption, notifies the output unit 313 of the determination result, and outputs a warning that the obstacle has occurred. It is processing to do. If at least one terminal can continuously receive packets sent by the terminal, it can be confirmed that the communication function of the terminal is operating continuously, so it is estimated that an obstacle is the cause. I can do it. When this process ends, the flowchart of FIG. 14 ends.

In this way, by utilizing the neighboring terminal information collected from each terminal, it is possible not only to determine whether or not the communication requirement for each terminal can be achieved, but also to analyze the cause of the communication interruption.

Referring to FIG. 15, an example of a warning display at the time of communication interruption that is output via the output unit 313 of the gateway will be described. FIG. 15A shows an example of a normal screen display output via the gateway output unit 313. In the neighboring terminal information collected from “A” (terminal 200-A) at a certain timing, “ It is assumed that the reception record from “C” (terminal 200-C) has been interrupted for a certain period. At this time, referring to the neighboring terminal information of “D” (terminal 200-D) and “F” (terminal 200-F) in which reception from “C” was recorded in the past in step 1402 of FIG. Similarly, it is determined whether or not the reception record from “C” is interrupted. If the reception record is interrupted in any case, it is determined that the failure of “C” is the cause, and the display regarding the communication quality in the communication interruption section is turned off as shown in FIG. Display a warning that it has stopped.

On the other hand, if it is confirmed that at least “D” or “F” neighboring terminal information continues to be received from “C”, it is determined that the cause is the occurrence of an obstacle on the transmission path. For example, if only the terminal “A” has no record of reception from “C”, it is suspected that an obstacle has occurred between “C” and “A”. In this way, only the display related to the communication quality of the section is turned off, and a warning 1500 is output instead. In this way, by changing the display method according to the cause of the communication interruption, the user can visually grasp the cause, and can quickly determine the measure for eliminating the communication interruption. However, the display method of FIG. 15 is an example, and is not necessarily limited to the format of FIG. In addition, in order to construct a stable communication system in which each terminal satisfies communication requirements, after performing communication quality measurement processing based on the collection of neighboring terminal information described in this embodiment, after constructing a stable communication system once However, this measurement process is effective. Specifically, the neighboring terminal information collection process of FIG. 6 is repeatedly performed for each terminal at a fixed period, and the display as shown in FIG. 11 and FIG. Etc. can be quickly grasped.

Embodiment 2 describes an embodiment that realizes a communication quality measurement process when a communication path that can be used by each terminal cannot be grasped in advance. For example, a case where a terminal that does not store route information is installed in the field without performing prior design of the communication route corresponds to this embodiment. When the usable communication path cannot be grasped in advance, the gateway cannot calculate the communication path specified in the neighboring terminal information collection process until the neighboring terminal information is collected from each terminal at least once. Therefore, in the second embodiment, it is necessary to perform neighboring terminal information collection processing by a method different from that of the first embodiment shown in FIG.

The neighboring terminal information collection process according to the second embodiment will be described with reference to FIG. Note that steps that perform the same processing as the neighboring terminal information collection processing according to the first embodiment are denoted by the same reference numerals as in FIG. 6, and description thereof is omitted. Further, since various configurations and processes according to the second embodiment are the same as those of the first embodiment except for the neighboring terminal information collection process, description thereof will be omitted.

In FIG. 16, in step S1601, the gateway selects a terminal from which neighboring terminal information is collected by the neighboring terminal information management unit 304, sets the terminal as a final destination, and transmits a neighboring terminal information request packet by flooding. It is processing to do. In the flooding, all the terminals that have received a packet perform a relay process, and when the same packet is received again, it is discarded without relaying. By transmitting the packet by flooding, it is possible to deliver the packet to a desired final destination terminal even when the packet is scattered over a wide range and the communication path on the way is not grasped.

Step S1602 is a process in which the terminal that receives the neighboring terminal information request packet relays the packet by flooding. At this time, when the communication processing unit 202 of the own terminal refers to the final destination information of the packet and confirms that it is not the final destination terminal designated as the gateway, the own terminal information is added as the route information to the neighboring terminal information request packet. After that, relay processing by flooding is performed. This is because by adding the route information, it is possible for the terminal that has received the packet to know through which communication path it has been transmitted in the flooding process.

Thereafter, after the final destination terminal designated by the gateway receives the neighboring terminal information request packet, the response request packet and the response packet are transmitted / received (steps S603 to S607), and the process proceeds to step S1603.

In step S1603, the terminal that has received the neighboring terminal information request packet in step S603 refers to the information in the neighboring terminal management table 205 in the neighboring terminal management information management unit 204, and transmits the neighboring terminal information response packet to the gateway. It is processing. At this time, as in step S608 of FIG. 6, the information of the neighboring terminal management table 205 held by the own terminal is stored in the neighboring terminal information response packet, and the final destination of the packet is set to the gateway, and at the same time, the communication that passes Also specify the route. However, the communication path specified here is based on the route information stored in the flooding process in the neighboring terminal information request packet, and the communication route is specified in the form of reversing the route order. Since the neighboring terminal information request packet is transmitted by flooding, there may occur a case where the final destination terminal receives the packet a plurality of times and there are a plurality of specifiable communication paths.

In this case, select one communication path. For example, a method of selecting the route information of the neighboring terminal information request packet received first, a method of selecting a route that can reach the gateway with the smallest number of hops, and the like can be considered. The communication path selection criterion is not limited to a specific method, and may be selected according to an arbitrary criterion. After transmitting the neighboring terminal information response packet, when the gateway receives the packet and finishes recording the neighboring terminal information (steps S609 to S611), the neighboring terminal information collecting process in FIG. 16 is terminated.

As described above, in the second embodiment, when the neighboring terminal information request packet is transmitted from the gateway to the terminal in the neighboring terminal information collection process, transmission is performed using flooding. As a result, even when the communication path that can be used by each terminal is not known in advance, the packet can be delivered to a desired terminal, and neighboring terminal information can be collected. When the neighboring terminal information is collected once from each terminal, the gateway can calculate the communication path to each terminal by the path calculation unit 306.

Therefore, in the second and subsequent neighboring terminal information collection processing, even in the second embodiment, the neighboring terminal information request packet may be transmitted by designating the route as shown in FIG. An advantage of transmitting the neighboring terminal information request packet by flooding is that more terminals can obtain a reception opportunity in one neighboring terminal information collection process. However, since all terminals perform flooding relay processing, the traffic load increases, and there is a possibility that the probability of occurrence of packet loss increases due to radio wave interference caused by simultaneous transmission of a plurality of terminals. It is possible to avoid interference to some extent by performing processing such as inserting random time jitter before relay processing, but it is completely avoided when many terminals are crowded. It is difficult to do.

In such a case, it is desirable to collect the neighboring terminal information from each terminal and change to the neighboring terminal information collecting process that does not use the flooding of FIG. 6 when the gateway can calculate the communication path.

1: communication system, 100: application server, 200: terminal, 201: storage device, 202: communication processing unit, 203: route management unit, 204: neighboring terminal information management unit, 205: neighboring terminal management table, 206: central control Device: 207: Power supply circuit, 208: RF peripheral circuit, 300: Gateway, 301: Storage device, 302: Communication processing unit, 303: Path management unit, 304: Neighboring terminal information management unit, 305: Neighboring terminal management table, 306 : Route calculation unit, 307: relay necessity determination unit, 308: failure detection / analysis unit, 309: central control unit, 310: power supply circuit, 311: RF peripheral circuit, 312: external network connection circuit, 313: output unit

Claims

Multiple devices connected to the network,
A gateway, the terminal is a radio wave transmission source, a storage area for storing a neighboring terminal management table including communication quality of communication between the transmission source,
When the own terminal receives communication, the transmission source, and the neighboring terminal information management unit that records the communication quality at the time of reception as neighboring terminal information in the neighboring terminal management table;
A communication system comprising: a communication processing unit that refers to the neighboring terminal management table when a transmission request for the neighboring terminal information is received and transmits the neighboring terminal information to a request source.
The gateway is
A communication processing unit that transmits a packet requesting information of the neighboring terminal management table to the terminal;
A route management unit that specifies the transfer route of the packet;
When there is a terminal whose communication quality is to be measured, a route calculation unit that calculates at least one of a route passing through the terminal or a route passing through a neighboring terminal capable of directly communicating with the terminal as a designated route is provided. The communication system according to claim 1.
The gateway is
Based on the information in the neighboring terminal management table collected from the terminal, determine whether each terminal can achieve the predetermined communication requirements,
When there is a terminal that cannot determine whether or not the communication requirement can be achieved by using only the information of the neighboring terminal management table collected in the past, a neighboring terminal information management unit that selects the terminal as a terminal for measuring communication quality is provided. The communication system according to claim 2.
The terminal
When the information of the neighboring terminal management table is requested, a packet requesting a response to the neighboring terminal is transmitted by broadcast,
The communication system according to claim 3, further comprising a communication processing unit that transmits a response packet to a response request source when a packet related to a response request is received from another terminal.
The gateway includes an output unit that refers to information in a neighboring terminal management table collected from a terminal and displays a communication quality between each terminal and the gateway, and a change transition of the communication quality in a specific section. 4. The communication system according to 4.
The gateway refers to the information in the neighboring terminal management table collected from the terminal, and there is an isolated terminal that does not have a communicable terminal and a terminal that can communicate, but the communication quality has not reached a predetermined value. A repeater necessity determination unit for determining a terminal;
6. The communication system according to claim 5, further comprising an output unit that displays whether or not a terminal needs to install a repeater and a priority related to the installation of the repeater.
The gateway refers to the information of the neighboring terminal management table collected from the terminal, and determines that the communication is broken when the reception record from the specific terminal is continuously broken for a predetermined period in the neighboring terminal management table of the terminal. ,
A failure detection analysis unit that refers to the neighboring terminal management table of other terminals, determines whether or not the reception record from the terminal is similarly interrupted, and analyzes the cause of the communication interruption;
The communication system according to claim 6, further comprising: an output unit that displays a message indicating the occurrence of communication interruption and a warning indicating the cause of the communication interruption.
Communication comprising a plurality of terminals connected by a network and a gateway, wherein the terminal includes a radio wave transmission source and a storage area for storing a neighboring terminal management table including communication quality of communication with the transmission source A system management method,
When the neighbor terminal information management unit receives the communication, the sender and the communication quality at the time of reception are recorded as neighbor terminal information in the neighbor terminal management table,
A communication system management method, comprising: referring to the neighboring terminal management table when a communication processing unit receives a transmission request for neighboring terminal information, and transmitting the neighboring terminal information to a request source.
The communication processing unit of the gateway transmits a packet requesting information of the neighboring terminal management table to the terminal,
The route manager specifies the transfer route of the packet,
When there is a terminal whose communication quality is to be measured by the route calculation unit, the route calculating unit calculates at least one of a route passing through the terminal or a route passing through a neighboring terminal capable of directly communicating with the terminal as a designated route. The communication system management method according to claim 8.
Based on information in the neighboring terminal management table collected from the terminal, the neighboring terminal information management unit of the gateway determines whether each terminal can achieve a predetermined communication requirement,
The terminal is selected as a terminal for measuring communication quality when there is a terminal for which it is not possible to determine whether or not the communication requirement can be achieved by only information in the neighboring terminal management table collected in the past. Management method of the communication system.
When the communication processing unit of the terminal is requested for information of the neighboring terminal management table, it broadcasts a packet requesting a response to the neighboring terminal, and
11. The management method for a communication system according to claim 10, wherein when a packet related to a response request is received from another terminal, a response packet is transmitted to a response request source.
The output unit of the gateway refers to the information of the neighboring terminal management table collected from the terminal, and displays the communication quality between each terminal and the gateway, and the change transition of the communication quality in a specific section. A management method of the communication system described.
The relay repeater necessity determination unit of the gateway refers to the information of the neighboring terminal management table collected from the terminal, and there is an isolated terminal that does not have a communicable terminal and a terminal that can communicate but the communication quality is determined in advance To determine which devices have not reached the given value,
13. The communication system management method according to claim 12, wherein the output unit displays whether or not the terminal needs to install a repeater and a priority regarding the repeater installation.
When the failure detection analysis unit of the gateway refers to the information of the neighboring terminal management table collected from the terminal and the reception record from the specific terminal in the neighboring terminal management table of the terminal is continuously interrupted for a predetermined period of time, Judged that communication was disrupted,
Refer to the neighboring terminal management table of other terminals, determine whether or not the reception record from the terminal is similarly interrupted, analyze the cause of the communication interruption,
The communication system management method according to claim 13, wherein the output unit displays a message indicating the occurrence of communication interruption and a warning indicating the cause of the communication interruption.