JP2000115171A - Radio communication network - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication network for realizing inexpensive and easy data communication by using radio communication. SOLUTION: Radio terminals 2 are distributed and installed in a mesh shape with a specified interval and a radio mesh 1 is constituted. The radio terminals 2 adjacent to each other are communicable, and by transferring and relaying packet data between the adjacent radio terminals 2, data are transferred between optional terminals. Also, as a congestion processing, the radio terminal 2 changes a transmission speed corresponding to a data amount inside a network and changes a transfer speed by a transmission destination. Further, at the time of data transmission, directivity is provided. Also, for the collision of counter radio waves, plural channels are provided and the data are transmitted from the two or more channels. Further, the respective radio terminals 2 are provided with a function for selecting the closest one of plural connection points. Also, a server for maintenance management can be connected to the radio mesh 1 as well.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless communication network technology in which a plurality of devices transmit and receive data by wireless communication, and more particularly, a source wireless terminal connected to a wireless communication network transmits various types of information to packets. The present invention relates to a technique used in a system that transmits a call to a destination wireless terminal while repeating transmission by another wireless terminal while repeating the relay.

[0002]

2. Description of the Related Art In recent years,
The demand for data communication is increasing exponentially, and the purpose of its use is also diversifying. As a result, various data communication methods using existing facilities such as telephone lines or new infrastructure have been proposed and put into practical use. However, these have high communication costs and require a great deal of cost for maintenance and maintenance of the infrastructure.

[0003] However, with an increase in communication demand, there is a need for a communication network that has lower communication costs than existing ones and that can easily install and maintain equipment, depending on the purpose of use of the communication network. In particular, there is a growing need for a data communication system that can be easily installed and maintained and that is easy to operate, for use by local businesses as part of public services.

[0004] It is an object of the present invention to provide a communication network which uses radio communication, realizes easy data communication with low cost of introduction and maintenance of equipment, low communication cost and low maintenance cost of infrastructure. .

[0005]

A wireless communication network system according to the present invention comprises a plurality of wireless terminals for performing wireless data communication, and each of the wireless terminals is directly or via one or more other wireless terminals. It is assumed that communication with all other wireless terminals is possible.

According to a first aspect of the present invention, each of the wireless terminals includes a traffic amount measuring means for measuring a data receiving interval from another wireless terminal, and data transfer when the receiving interval is narrowed. And a data transfer rate adjusting means for lowering the rate. With this configuration, the amount of data flowing through the entire network is adjusted.

Further, according to a second aspect of the present invention, the first wireless terminal which is one of the wireless terminals is a second wireless terminal having a direct communication path to itself. When transmitting data to the first wireless terminal, the data is transmitted at a speed higher than a normal communication speed, and when transmitting data to the first wireless terminal, the transmission speed is reduced. Thereby, it is possible to cope with concentration of traffic to a specific wireless terminal in the network.

According to a third aspect of the present invention, in the wireless terminal, the wireless terminal measures a communication frequency of a communication path set for itself, and a communication path for transferring received data. And a communication path determining means for determining the communication frequency based on the communication frequency, thereby preventing traffic from concentrating on a specific portion in the network.

Further, in the invention according to claim 4 of the present invention, the wireless terminal has a plurality of communication channels as communication paths with an adjacent wireless terminal, and data transmission is performed from two or more of the communication channels. The transmission is characterized by this, and it is possible to cope with collision of wireless data.

[0010] In the invention according to claim 5 of the present invention, in the invention according to claim 4, the wireless terminal includes:
When data is received, the channel is sequentially switched while confirming the presence or absence of a radio wave, whereby data transmitted from the wireless terminal can be reliably received.

According to a sixth aspect of the present invention, in the fourth or fifth aspect, the head of the data to be transmitted has a preamble at the beginning thereof. Data can be received without receiving from the beginning of the packet.

Further, the invention according to claim 7 of the present invention is characterized in that the wireless terminal performs wireless output with directivity at the time of data transmission, and this configuration reduces the distance between the wireless terminals. It is possible to take a large amount and to reduce power consumption.

[0013] According to the invention described in claim 8 of the present invention, in the invention described in claim 7, the wireless terminal includes:
In this configuration, the wireless terminal receives data output from another wireless terminal while changing the reception directivity at the time of idle, and obtains the direction of the wireless terminal from the radio wave intensity of the received data. You can know the direction of the terminal.

According to a ninth aspect of the present invention, when the wireless terminal has a plurality of destinations in the network, the wireless terminal selects a destination having the smallest number of hops. The destination with the least number of times is selected.

According to a tenth aspect of the present invention, the wireless terminal includes a communication frequency measuring means for measuring a communication frequency of a communication path set for itself, and a communication path to the destination. When there are a plurality of communication channels, a communication path determination unit that determines the communication path based on the communication frequency is provided, which prevents traffic from concentrating on a specific portion in the network.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. First, a network configuration in the present embodiment will be described.

FIG. 1 is an image diagram of a wireless communication network in the present embodiment. In the present embodiment, wireless devices are distributed and installed at specific intervals in a specific area. Each wireless device can communicate with a wireless device adjacent to each other, and can transfer packetized data between adjacent wireless devices, and by repeating this, can transfer data between arbitrary terminals. In the following description, this group of wireless devices is called a wireless mesh. Also, a wireless device constituting a wireless mesh is called a wireless terminal, and a terminal device used by a user to connect to a network is called a terminal device.

Each network user can use this network by connecting wirelessly or by wire from one of his / her own terminal devices 3 and 4 to one of the wireless terminals 2 constituting the wireless mesh 1. A wireless terminal is connected to a telephone line or the Internet, and data communication with another network can be performed via the wireless terminal 5.

Since the communication between the terminal devices 3 and 4 and the wireless terminal 2 and the communication between the wireless terminals 2 are packet exchanges, the connection between the terminal devices 3 and 4 and the network occupies a line like a telephone line. Because it is not something that keeps it connected,
Although the communication speed becomes slow as the traffic increases, a very large number of terminal devices 3 and 4 can be connected.

This wireless mesh is provided, for example, by placing wireless terminals on a telephone pole or the like at a distance of about 300 m in a specific area on a telephone pole, for example, to provide a population of about 150,000 and an area of about 3
Assuming that Hino City is 0 km ^2, the entire city can be covered by installing about 300 wireless terminals.

Since the installation of the wireless terminal can be performed simply by placing the wireless terminal around, the construction cost can be reduced as compared with the installation of a wired cable such as a telephone line. Also, the price of the wireless terminal alone is low, and the maintenance of the infrastructure can be performed at a lower cost than other network systems of the same scale.

Further, in the case of a telephone line or the like, failure and maintenance cannot be handled by an amateur, but in the network of this embodiment,
Since repairs and maintenance only require replacement of the wireless terminal, no special specialist for maintenance is required. Therefore, the maintenance work is hardly required, and the operation cost is very low. Therefore, the operation cost is reduced, and the communication fee can be suppressed to a low level.

Further, since this network system is a distributed network system and does not have a structure in which control is concentrated on a specific portion, even if a part of the wireless mesh is lost, the whole network does not go down and operates normally. The wireless terminals connected to the part of the wireless mesh being connected can communicate with each other. Therefore, by securing a power source by, for example, mounting a battery or a solar cell in each wireless terminal, the wireless terminal can be used as an emergency communication system for disasters such as earthquakes. 1. Basic operation of network A communication method using the wireless mesh will be described.

First, setting of a communication path and selection of a relay route in the wireless mesh will be described. FIG. 2 is an explanatory diagram of a method of setting a communication path between the installed wireless terminals. In the drawing, A to J indicate wireless terminals distributed and installed in the area.

Each of the radio terminals A to J transmits a presence notification packet including an identifier for identifying each transmission source terminal at a predetermined period, and the communication terminal receiving this can directly communicate with the communication terminal. Recognize that there is sex.

In FIG. 2, radio terminals A, B, D, E, F
Receives the presence notification packet transmitted by the wireless terminal C, and recognizes that it has a possibility of directly communicating with the wireless terminal C. Similarly, the wireless terminals F, G,
By receiving the presence notification packet transmitted by the wireless terminal I, H and J recognize that they have a possibility of directly communicating with the wireless terminal I.

As described above, each of the wireless terminals A to J transmits the presence notification packet at a fixed period, and the adjacent wireless terminal receives the packet, whereby the direct communication according to the radio wave propagation state at that time is performed. Can recognize each other.

Next, each wireless terminal transmits a communication path diagnosis packet, diagnoses the reliability of the communication path between each wireless terminal having the possibility of direct communication recognized by the presence notification packet, and The one having reliability is set as an effective communication path.

Thereafter, each wireless terminal stores system configuration information in order to recognize through which wireless terminal having a direct communication path with itself all other wireless terminals constituting the system. To send a presence notification packet.

The system configuration information is information relating to the number of times of communication from the terminal and the terminating terminal. Each terminal holds, together with the system configuration information for itself, the system configuration information of an adjacent wireless communication terminal capable of direct communication. ,to manage.

FIG. 3 shows the system configuration information of the wireless terminal A when the network configuration has a topology as shown in FIG. The system configuration information of FIG. 3 shows the relationship between each destination wireless terminal and the minimum number of communication times to reach the wireless terminal when a network line having a topology as shown in FIG. 4 is set. ing. Here, the number of communication times (hop number) indicates the number of times that a packet transmitted by the wireless terminal A as the transmission source is communicated between the wireless terminals until the packet reaches the destination wireless terminal. From the system configuration information, it can be understood that there are B, C, and D in the wireless terminals to which the wireless terminal A can transfer the packet in one communication.
In addition, it can be seen that wireless terminals that require at least two times of communication to transfer a packet including the communication by the relay wireless terminal include E and F. Similarly, G, H, and I have at least 4 for wireless terminals requiring at least 3 communications.
It can be seen that J is present in the wireless terminal that requires communication twice.

Each wireless terminal stores the system configuration information as shown in FIG. 3 in the presence notification packet in the idle state and transmits it to the adjacent wireless terminal at regular intervals. Then, it updates its own system configuration information based on the system configuration information received from the adjacent wireless terminal.

Each wireless terminal holds and manages system configuration information of an adjacent wireless terminal in addition to its own system configuration information. FIG. 5 is managed by the wireless terminal A in FIG.
The configuration information of the wireless terminals B, C, and D in which the wireless terminal A has a direct communication path is shown. The wireless terminal A includes, in addition to its own system configuration information shown in FIG. 3, the wireless terminals B, C,
D also manages the system configuration information.

As an example of communication using this system configuration information, a case is considered where wireless terminal A sends a packet to wireless terminal E. Referring to the system configuration information in FIG. 5, it can be seen that a packet can be transferred from the wireless terminal B to the wireless terminal E in one communication. Similarly,
It can be seen that the transfer can be performed once from the wireless terminal C and twice from the wireless terminal D. As a result, the wireless terminal A sends a packet whose destination is the wireless terminal E to either the wireless terminal B or C. The wireless terminal B or C that has received the packet from the wireless terminal A sends the packet to the wireless terminal with the least number of communication with the destination of the packet from the system configuration information held and managed by itself,
Thereafter, by the same processing, the packet is relayed in the network and reaches the destination wireless terminal. 2. Congestion Processing Each wireless terminal includes a plurality of reception buffers in order to adjust the amount of data flowing in the network. In addition, the data reception interval is measured, and when the communication frequency is high and data is frequently received from another wireless terminal, the data transfer speed is reduced and the data transfer interval is increased.

FIG. 6 is a diagram showing the change of the transfer speed by the wireless terminal. As shown in FIG. 6A, each wireless terminal normally receives data and sequentially processes and outputs the data. However, when the data reception interval is narrowed, the wireless terminal determines that the amount of data flowing in the network is large, and adjusts the transfer interval of the received data using the reception buffer so that it becomes a certain size or more. . When the data reception interval becomes short, the wireless terminal determines that the amount of data flowing in the network has become small, returns the transmission speed, and upon receiving the data, sequentially processes and transfers the data.

As described above, by adjusting the data transfer rate according to the amount of data flowing in the network by each wireless terminal, it is possible to prevent the occurrence of a communication failure due to congestion.

The data transfer speed in the wireless mesh may be determined depending on the destination to which the data is transferred. FIG. 7 shows an example. For example, if a configuration is adopted in which position information indicating which wireless terminal is connected to a terminal device wirelessly connected to the wireless mesh is registered in one or more wireless terminals in the wireless mesh, traffic concentrates on this wireless terminal. There is a possibility of doing. Alternatively, communication data concentrates on a wireless terminal connected to a specific line like the wireless terminal 4 in FIG. Such concentration of traffic to a specific portion causes a reduction in the capacity of the entire network and a communication failure.

As shown in FIG. 7 (a), for the communication terminal which may cause traffic concentration, data going to the radio terminal 11 and radio terminal 11 as shown in FIG.
The data transfer speed is changed as shown in FIG.

For example, when the wireless terminal 11 is connected to the Internet, in many cases, data directed to the wireless terminal 11 is small and less important data such as key presses. Conversely, data transmitted from another wireless terminal adjacent to the wireless terminal 11 is large data such as content such as image data and audio data. Therefore, the data collected in one wireless terminal 11 as shown in FIG.
And is distributed from one wireless terminal 11 as described above, and is distinguished by a method such as attaching a specific code in a data packet. Then, as shown in FIG.
The ones gathered at the same time are transmitted at a slow speed with an interval between reception and transmission, and the ones emitted from the wireless terminal 11 are set so that the interval from reception to transmission is shorter than the interval between other wireless terminals. To increase the transfer speed. By adjusting the time from reception to transmission, the wireless terminal 11 can cope with the concentration of traffic on a specific part.

As a method of coping with congestion, there is a method of selecting a communication route according to the frequency of data passing through each communication path. As described above, the selection of the data transfer route in the wireless mesh is performed based on the system configuration information held by each wireless terminal, so that the route that minimizes the number of communication times (hop count) to the destination is selected. Is done. However, in general, there are countless routes in the wireless mesh to the same destination, and there are many routes having the same hop number. Therefore, by selecting the route with the least communication frequency from among the communication routes with the least number of hops to the destination and relaying the data, it is possible to prevent traffic from concentrating at a certain location.

As a method of realizing this, each wireless terminal measures the number of times data passes through a communication path set for itself within a specific time, and assigns a priority level to each communication path based on the value. Set. As this priority level, a value based on the communication frequency of the communication path is set, and a high priority level is set for a communication path with a small data passing amount. Then, as shown in FIG. 8, as the route of the received data to the destination, the number of hops is used to determine the communication route 25 to the wireless terminal 22, the communication route 26 to the wireless terminal 23, and the communication route 27 to the wireless terminal 24. If it is possible to go through two communication paths,
The priority level set for each communication path is checked, and the communication path with the highest priority level is selected. In the case of FIG. 9, priority levels 1, 3, and 3 are set for the communication paths 25, 26, and 27, respectively, and the communication path 25 with the highest priority level is selected, and data transmission is performed. .

As described above, when the other conditions are the same, the communication path is selected according to the frequency of passing data, so that it is possible to prevent traffic from being concentrated on a specific portion in the wireless mesh. 3. Multiplexing of Communication Channels As shown in FIG. 9A, when data is simultaneously transmitted from a plurality of adjacent wireless terminals 32 and 33 to one wireless terminal 31, these wireless data collide and the wireless terminal 31
Then, there is a strong possibility that data from any wireless terminal cannot be received. Therefore, in order to avoid this, each wireless terminal has a plurality of channels that are changed by changing a frequency, a time, or a spreading code and a combination of two or more of them. The channel division method is arbitrary such as frequency division, time division, spreading code division, or a combination thereof.

When the communication channels are multiplexed by a plurality of channels, the wireless terminals 32 and 33 on the transmitting side can transmit data from the plurality of channels as shown in FIG. 9B. The channel selection method on the transmission side is arbitrary, such as a method of performing carrier sensing before transmission, a random method, a method based on a specific rule, and the like.
Increasing the number of channels almost eliminates the possibility that all output data will collide with outputs from other wireless terminals.

The channel selection method of the wireless terminal 31 changes the receiving channel while confirming the presence / absence of radio waves in order. If the wireless terminal 32 or 33 waits on one of a plurality of channels transmitted, Thus, the transmitted data can be reliably received. In FIG. 9B, the wireless terminal 32
And 33, the wireless terminal 31 cannot receive data transmitted from channel 1 due to collision, but can receive data transmitted from channels 2 and 3.

In order to reliably receive data, a preamble is provided at the head of the packet as shown in FIG. The reception method of the wireless terminal 31 is a method in which the reception channel is sequentially changed and the reception channel is fixed when the detection of the output of the radio wave of the channel is performed. Not always. Therefore, by adopting a packet configuration in which a preamble of an appropriate size is provided before the transmission data, the receiving-side wireless terminal 31 can detect the radio wave at the time of transmitting the preamble even if it cannot receive from the beginning of the packet. To receive the subsequent data, and all necessary transmission data can be received. 4. Directivity at the time of reception by each wireless terminal Each wireless terminal in the wireless mesh has non-directionality when receiving data and has directivity when transmitting data.

FIG. 11A shows a state in which the wireless terminal receives data.
FIG. 11B is a diagram showing the directional characteristics at the time of data transmission. The wireless terminal 41 constituting the wireless mesh does not have directivity as shown in FIG.
No. 4 45 receives data uniformly from any direction.

At the time of data transmission, the transmission destination can be specified. Therefore, as shown in FIG. 11B, the wireless terminal 41 that performs data transmission has directivity in the direction of the transmission destination wireless terminal 44. Since the partner to which the wireless terminal 41 transmits data changes every time data is transmitted, the transmission direction is changed by using an adaptive array antenna as a transmission antenna, or the transmission is performed by mechanically rotating the directional antenna. Change direction.

In order for each wireless terminal to have directivity when transmitting data, it is necessary to know the direction in which the adjacent wireless terminals 42 to 44 are installed. Hereinafter, the detection method will be described.

The wireless terminal transmits a presence notification packet in the idle state, and each wireless terminal detects the direction of the adjacent wireless terminal by receiving the presence notification packet while changing the directivity at the time of reception.

FIG. 12 is a diagram for explaining the detection of the direction of the adjacent wireless terminal. Since the presence notification packet includes the identifier for identifying the wireless terminal, the wireless terminal 51 that has received this can recognize that the transmission source of the presence notification packet is the wireless terminal 52. Therefore, the wireless terminal 5
1 can track the presence notification packet output from the wireless terminal 52. Therefore, by measuring the radio wave intensity of this presence notification packet while changing the directivity at the time of reception, the directivity having the highest radio wave intensity can be obtained. In the direction, it can be determined that the wireless terminal that is the output source of the presence notification packet exists.

Using the direction of the adjacent wireless terminal obtained in this way, the transmission data is output to the target adjacent wireless terminal at the time of the data transmission described above. By giving directivity at the time of transmission in this manner, radio waves can be transmitted farther than in the case of the same output, so that the interval between wireless terminals constituting the wireless mesh can be increased. In addition, when radio waves reach the same distance, only small output is required, so that power consumption during data output can be suppressed. 5. Selection of destinations when there are multiple destinations Regarding selection of destinations when there are multiple destinations, FIG.
This will be described with reference to FIG.

For example, when connecting to the Internet using this network, if the wireless mesh 61 is connected to the Internet at a plurality of locations, the wireless mesh 61 may be connected to the Internet via any of the connection points.

For example, in FIG. 13, the wireless terminals 63 and 6
When the three wireless terminals 4 and 65 are gateway-connected to the Internet, the terminal device 69 communicating with the wireless terminal 62 can connect to the Internet via any of the wireless terminals.

In such a case, the terminal device 62 checks the number of hops to the terminal devices 63, 64 and 65 from the system configuration information held by the terminal device 62, and determines, as the data transfer destination, the one having the smallest number of hops Is set as the destination. In FIG. 13, the number of hops between the wireless terminals 63, 64, and 65 is 4, 4, and 3, respectively, so the wireless terminal 65 having the smallest number of hops is selected as the data transmission destination.
As a result, the closest one of the destinations is automatically selected.

As a communication route from the wireless terminal 62 to the wireless terminal 65, the wireless terminal 62
There are three channels to 8 and 69. No matter which of these three, the wireless terminal 65 can be reached with three hops. In such a case, the communication path is selected based on the priority level based on the communication frequency set in the above-described communication path.

FIG. 14 is a diagram for explaining the selection of the communication path. A communication path 71 to the wireless terminals 67, 68 and 69;
Priority levels 3, 2, and 2 are set to 72 and 73, respectively, based on the data passing amount. Wireless terminal 6
2 selects the communication path 71 based on this priority level and transmits data. 6. Network Maintenance Management Function The wireless communication network according to the present embodiment may be configured to further include a network maintenance management server.

FIG. 15 shows the configuration of a wireless communication network provided with this maintenance management server. This maintenance management server 8
Reference numeral 3 is connected to one of the wireless terminals constituting the wireless mesh, and each wireless terminal notifies the maintenance management server of its own operation record at regular intervals.

The maintenance management server 83 analyzes the operation record data collected via the wireless terminal 84, detects a concentrated portion of traffic in the network and a failed wireless terminal, and detects a wireless terminal with concentrated traffic or a failed wireless terminal. The other wireless terminals are instructed to avoid data transfer to the selected wireless terminal. In the case of a failure, the maintenance person of the network is notified of the location of the failure, the details of the failure, and the like, and the maintenance person repairs or replaces the failed wireless terminal based on the notification.

The function of the maintenance management server can be transferred to a portable computer 85 such as a notebook computer having a wireless communication function and capable of wireless communication.

When communication from the network becomes impossible, the maintenance management server 83 cannot determine whether this is due to the entire network being down or another cause such as a failure of the wireless terminal connected to the server. Therefore, the mobile computer 85 is moved to an appropriate place, connected to a network, and each wireless terminal is instructed to notify itself of the operation record, and the mobile computer 85 is used as a network maintenance management server. It is possible to determine whether the entire network is down or whether the maintenance management server has become unable to communicate due to other factors. In addition, by using the mobile computer for the maintenance management function and moving within the area to detect a failure location, it is possible to further narrow down the failure location in the network.

[0061]

According to the present invention, it is possible to provide a communication network in which equipment costs, construction costs, and maintenance costs are low, and no trouble is required for equipment maintenance. Therefore, the communication fee can be kept at a low level.

Further, since this wireless communication network is a distributed network, even if the network is partially lost, the entire network does not go down and is connected to a normally operating wireless mesh part. Wireless terminals can communicate with each other. Therefore, it can also be used as an emergency communication system for disasters such as earthquakes.

Further, in the wireless communication network according to the present invention, each wireless terminal constituting the network performs congestion processing based on the amount of data flowing on the network.
It is possible to prevent a communication failure due to congestion from occurring.

Communication between the wireless terminals is multiplexed, and the wireless terminals can cope with collision of output radio waves by transmitting data from a plurality of channels when transmitting data.

Further, since each wireless terminal has directivity at the time of data transmission, it is possible to reach radio waves farther with the same output, and therefore, the interval between each wireless terminal can be increased. In addition, when radio waves reach the same distance, only small output is required, so that power consumption during data output can be suppressed.

If there are a plurality of external connection points in the communication network, the closest connection point is selected. Further, by providing the maintenance management server in the network, it is possible to collect information on the communication state and the failure in the network.

[Brief description of the drawings]

FIG. 1 is an image diagram of a wireless communication network according to an embodiment.

FIG. 2 is a diagram illustrating a situation where wireless terminals C and I transmit a presence notification packet.

FIG. 3 is a diagram showing system configuration information of a wireless terminal A;

FIG. 4 is a diagram illustrating a topology example of a wireless communication network.

FIG. 5 is a diagram showing configuration information of wireless terminals B, C, and D having a direct communication path with the wireless terminal A, which is managed by the wireless terminal A.

FIG. 6 is a diagram illustrating a change of a transfer speed by a wireless terminal.

FIG. 7 is a diagram illustrating a change in data transfer speed depending on a destination to be transferred;

FIG. 8 is a diagram illustrating selection of a communication channel based on communication frequency.

FIG. 9 is a diagram illustrating multiplexing of communication paths.

FIG. 10 is a diagram illustrating a configuration example of a packet when multiplexing communication channels.

11A is a diagram illustrating the directional characteristics of a wireless terminal when receiving data, and FIG. 11B is a diagram illustrating the directional characteristics of the wireless terminal when transmitting data.

FIG. 12 is a diagram illustrating detection of a direction of an adjacent wireless terminal.

FIG. 13 is an explanatory diagram of a destination selection method when there are a plurality of destinations.

FIG. 14 is a diagram illustrating selection of a communication path.

FIG. 15 is a diagram illustrating a configuration example of a wireless communication network system including a maintenance management server.

[Explanation of symbols]

1,61,81 Wireless mesh A to J, 2,5,11,21,22,23,31,3
2, 33, 41, 42, 43, 44, 45, 51, 5,
2, 62, 63, 64, 65, 66, 67, 68, 8
2, 84 Wireless terminal 3, 4, 69 Terminal device 25, 26, 27, 71, 72, 73 Communication path 83 Maintenance management server 85 Mobile computer

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazuhiro Tsuchiya 1-1 Tanabe Nitta, Kawasaki-ku, Kawasaki City, Kanagawa Prefecture Inside Fuji Electric Co., Ltd. (72) Inventor Taku Uchiyama 1st Tanabe Nitta, Kawasaki-ku, Kawasaki City, Kanagawa Prefecture No. 1 Fuji Electric Co., Ltd. (72) Inventor Hideaki Yanagihara 1-1, Tanabe Nitta, Kawasaki-ku, Kawasaki City, Kanagawa Prefecture Inside Fuji Electric Co., Ltd. (72) Satoshi Suzuki 1, Tanabe Nitta, Kawasaki-ku, Kawasaki City, Kanagawa Prefecture No. 1 Fuji Electric Co., Ltd. (72) Inventor Rika Tsukada 1-1, Tanabe Nitta, Kawasaki-ku, Kawasaki City, Kanagawa Prefecture Inside Fuji Electric Co., Ltd. (72) Koji Toshigami 1, Tanabe Nitta, Kawasaki-ku, Kawasaki City, Kanagawa Prefecture No. 1 Fuji Electric Co., Ltd. F term (reference) 5K033 AA04 CB01 CB06 CB17 CC01 DA01 DA19 DB18 EA07 EC03

Claims (10)

[Claims] 1. A wireless communication system comprising a plurality of wireless terminals performing wireless data communication, wherein any of the wireless terminals can communicate with all other wireless terminals directly or via one or more other wireless terminals. In the network system, each of the wireless terminals includes: a traffic amount measurement unit that measures a data reception interval from another wireless terminal; and a data transfer speed adjustment unit that reduces a data transfer speed when the reception interval is narrowed. A wireless communication network system, characterized in that: 2. A wireless communication system comprising a plurality of wireless terminals performing wireless data communication, wherein any of the wireless terminals can communicate with all other wireless terminals directly or via one or more other wireless terminals. In the network system, a first wireless terminal, which is one of the wireless terminals, transmits data to a second wireless terminal having a direct communication path with respect to the first wireless terminal. Wherein the second wireless terminal reduces the transmission speed when transmitting data to the first wireless terminal. 3. A wireless communication system comprising a plurality of wireless terminals performing wireless data communication, wherein any of the wireless terminals can communicate with all other wireless terminals directly or via one or more other wireless terminals. In the network system, each of the wireless terminals includes: a communication frequency measuring unit configured to measure a communication frequency of a communication channel set for itself; and a communication channel determining unit configured to determine a communication channel to transfer received data based on the communication frequency. A wireless communication network system comprising: 4. A wireless communication system comprising a plurality of wireless terminals performing wireless data communication, wherein any of the wireless terminals can communicate with all other wireless terminals directly or via one or more other wireless terminals. In the network system, the wireless terminal has a plurality of communication channels as communication paths with adjacent wireless terminals, and data transmission is performed from two or more of the communication channels. 5. The wireless communication network system according to claim 4, wherein the wireless terminal sequentially switches the channel while confirming the presence or absence of a radio wave when receiving data. 6. The wireless communication network system according to claim 4, wherein a head portion of the data to be transmitted has a preamble. 7. A wireless communication system comprising a plurality of wireless terminals performing wireless data communication, wherein any of the wireless terminals can communicate with all other wireless terminals directly or via one or more other wireless terminals. In the network system, the wireless terminal wirelessly outputs with directivity at the time of data transmission. 8. The wireless terminal receives data output by another wireless terminal while changing the reception directivity during an idle time, and obtains the direction of the wireless terminal from the radio wave intensity of the received data. The wireless communication network system according to claim 7, wherein 9. A wireless communication system comprising a plurality of wireless terminals performing wireless data communication, wherein any of the wireless terminals can communicate with all other wireless terminals directly or via one or more other wireless terminals. In the network system, the wireless terminal selects a destination with the smallest number of hops when there are a plurality of destinations in the network. 10. A communication frequency measuring means for measuring a communication frequency of a communication path set for itself, and when there are a plurality of communication paths to the destination, the wireless terminal sets the communication path based on the communication frequency. The wireless communication network system according to claim 9, further comprising: a communication path determining unit that determines the wireless communication network.