JP3451233B2 - Multi-hop wireless networks and radio stations - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is based on the fact that each wireless station has a relay function in a star type wireless network in which a plurality of wireless stations such as mobile communication and wireless LAN access the same base station. The present invention relates to a multi-hop wireless network in which wireless stations existing outside the communication area of the base station can relay the wireless stations to access the base station.

In particular, the present invention relates to a multi-hop wireless network and a wireless station for autonomously constructing a relay path from each wireless station to a base station.

[0003]

2. Description of the Related Art In mobile communication such as PDC and PHS,
In order to access the communication network, each wireless station once accesses the base station directly connected to the communication network. These systems have a star-type wireless network configuration in which a plurality of wireless stations access the same base station, and the communication area of each base station becomes the communication service available area of the system as it is.

Here, in the case of PDC, since the communication area of the base station covers a radius of several kilometers, it is possible to provide a wide range of communication services with a small number of base stations, but in the case of PHS, the communication area of the base station is several hundreds. Therefore, it is necessary to arrange a large number of base stations in order to provide a wide range of communication services. In addition, with the increasing demand for higher transmission speeds in the future, it is possible to use base stations that use high frequency bands such as wireless LANs for mobile communications, and the transmission / reception area will be even larger than that of PHS base stations. It may be narrowed.

In such a system in which the communication area of the base station is small, as a method of expanding the service providing area, there is a method of forming a multi-hop wireless network between the wireless stations. What is a multi-hop wireless network?
This is a network configuration in which each wireless station has a relay function, and a plurality of wireless stations existing between the wireless stations that cannot directly communicate with each other relay a signal, so that the wireless stations can communicate with each other.

When this multi-hop wireless network is applied to the star type wireless network described above, for example, a function of relaying a signal transmitted from a wireless station outside the communication area of a certain base station (hereinafter referred to as "outside area wireless station") When a nearby wireless station (hereinafter referred to as "relay wireless station") that receives the signal is received, this relay wireless station transfers the received signal to a relay wireless station closer to the base station (hereinafter referred to as "upper"), and this relay The wireless station transfers the received signal to a higher relay wireless station, and then sequentially transfers the received signal to the base station via the higher relay wireless station. This allows the base station to receive the signal transmitted from the out-of-area wireless station. Also, the signal transmitted from the base station can be received by the out-of-area wireless station by following a route that is completely opposite to the above.

Therefore, by forming a multi-hop wireless network between the wireless stations, wireless stations outside the communication area of the base station can communicate with the base station. As a result, even in a system such as a wireless LAN where the communication area of the base station is narrow, it is possible to autonomously expand the service providing area of the base station among the wireless stations.

In a general multi-hop wireless network, a relay path must be established between a source wireless station and a destination wireless station in order to deliver a signal from an arbitrary wireless station to a destination wireless station. There is. However, in the above star-type wireless network, the destination of the signal transmitted from each wireless station is always the base station, so each wireless station only needs to establish a relay path to the base station. That is, since each wireless station establishes only one relay path, it is sufficient to determine one upper connection destination wireless station (relay wireless station, base station) to which each wireless station relays and transfers signals. . In other words, if each wireless station uniquely determines the upper connection destination wireless station, the signal from any wireless station is transferred to the base station by each wireless station transferring to the upper connection destination wireless station. Become.

Therefore, in order to apply the multi-hop wireless network to the above star type wireless network, the base station is the highest station between the base stations and the wireless stations, and each wireless station has a unique upper connection destination wireless station. A structure (hereinafter referred to as "star-type multi-hop wireless network") defined in 1) may be constructed. Here, FIG. 1 shows a configuration example of a star-type multi-hop wireless network in which a base station is the highest station. In the figure, S is a base station, M is a wireless station, and an arrow indicates a higher-level connection destination wireless station.

As a conventional method of constructing a star type multi-hop wireless network, there is a centralized control method by the highest station. This is because each wireless station notifies the top station of all the other wireless stations that it can connect to, and it understands all the star-type multi-hop wireless network configurations that the top station can realize, and then selects the optimal one. This is a construction method in which a star-type multi-hop wireless network configuration is selected and the connection destination is instructed to each wireless station.

[0011]

Such a centralized control construction method needs to be reconstructed when a certain radio station cannot perform the relay function due to a failure or movement.
In order for the top station to know that a broken or moved radio station can no longer carry the relay function, the radio stations connected to that radio station first notify the top station. However, upon receiving this notification, the highest-level station must once again determine the optimum connection destination wireless station for each wireless station due to the reconstruction of the star-type multi-hop wireless network, and notify all wireless stations of it. The same operation is required when a new wireless station is added.

Therefore, according to the centralized control construction method, when a certain wireless station cannot be relayed due to a failure or movement, or when a new wireless station is added, the star type multi-hop wireless network is re-established. There was a problem that the time required for construction became long and the network configuration could not be changed immediately. In addition, there is a problem that control traffic such as change notification traffic and broadcast traffic for change is increased.

According to the present invention, each radio station does not control all the construction of the star type multi-hop radio network by the highest-level station (base station), but each radio station finds an optimal connection destination radio station. An object is to provide a multi-hop wireless network and a wireless station that can be autonomously constructed.

[0014]

The invention according to claim 1 shows a method for constructing a multi-hop wireless network. That is, when the hop number information acquisition means of each wireless station acquires the hop number information from the connectable wireless stations and the upper connection destination wireless station selection means can directly connect to the base station, the base station is set as the upper connection destination wireless station. If it is not possible to connect directly to the base station, select one connectable wireless station that has the minimum number of hops obtained from the hop number information from the connectable wireless stations as the upper connection destination wireless station, and transfer the signal. Each wireless station autonomously constructs a multi-hop wireless network by transferring the transmission signal or the signal received from the child wireless station to the upper connection destination wireless station, or to the base station if directly connectable to the base station can do.

Although this is premised on that each wireless station recognizes the hop number of its own wireless station in advance, if it is undecided, it is determined in order from the side closer to the base station. That is, the hop number information acquisition means of the wireless station which can be directly connected to the base station sets the hop number of its own wireless station to 1, and the hop number information acquisition means of the other wireless stations is selected by the upper connection destination wireless station selection means. By setting the hop count of the upper connection destination wireless station plus 1, as the hop count of the own wireless station, the hop count of each wireless station forming the multi-hop wireless network is determined in order from the one closest to the base station. (Claim
2, 7) . Then, by selecting one upper connection destination wireless station for each wireless station, each wireless station can autonomously construct a multi-hop wireless network.

[0016]

Further, the hop number information acquisition means of the wireless station according to the invention of claim 1 simultaneously transmits the broadcast message at a transmission timing based on the hop number of its own wireless station as the hop number information, and The configuration is such that the hop count information of the connectable wireless station is acquired according to the reception timing of the notification message. The invention according to claims 8 and 9
Shows another configuration of the hop count information acquisition means of the wireless station.
That is, the hop count information acquisition means of the wireless station according to claim 8.
Is a broadcast that includes the number of hops of its own wireless station as hop number information.
The message is always sent in a broadcast
Information on hop count of connectable wireless stations
Is a configuration for acquiring.

The hop count information acquiring means of the radio station according to claim 9 transmits a signal requesting the connectable radio station to notify the hop count information, and the connectable radio station which has received the request signal itself. This is a configuration in which a signal for replying the hop count information of the wireless station is transmitted to the connectable wireless station that has requested the response, and the wireless station that receives this response signal acquires the hop number information for the connectable wireless station.

In any of the above configurations, the hop count information acquisition means can acquire the hop count information from the connectable wireless stations, and the hop count becomes the minimum 1
If one connectable wireless station is selected as the upper connection destination wireless station, a multi-hop wireless network is autonomously constructed.

The invention according to claim 3 or claim 10 shows a configuration when a new wireless station enters a multi-hop wireless network. The hop number information acquisition means of the wireless station receives the notification message from the connectable wireless station and acquires the hop number information, or acquires the hop number information according to the reception timing of the notification message from the connectable wireless station. Alternatively, by transmitting a request signal to the connectable wireless station, receiving a response signal corresponding to the request signal, and acquiring the hop count information, one connectable wireless station having the minimum hop count is connected to the upper connection destination wireless station. And can join the multi-hop wireless network.

The invention described in claims 4 , 5 and 6 shows a configuration for reconstructing a multi-hop wireless network. That is, the hop count information acquisition means and the upper connection destination radio station selection means of the radio station according to claim 4 minimizes the hop count from the connectable radio stations at a predetermined timing after the multi-hop radio network is constructed. This is a configuration in which one connectable wireless station is selected, and when the connectable wireless station and the current upper connected wireless station do not match, the connectable wireless station is selected as a new upper connected wireless station.

When the hop count information acquisition means and the upper connection destination wireless station selection means of the wireless station according to claim 5 cannot connect to the upper connection destination wireless station after constructing the multi-hop wireless network, the new connection is newly made. This is a configuration in which one connectable wireless station having the smallest hop count is selected as the upper connection destination wireless station from the connectable wireless stations, excluding the child wireless stations.

The hop count information acquisition means and the upper connection destination wireless station selection means of the wireless station according to claim 6 , when it becomes impossible to connect to the upper connection destination wireless station after constructing the multi-hop wireless network, To the child radio station by a connection unacceptable signal, and after the announcement, one connectable radio station with the smallest number of hops is selected from the connectable radio stations as the upper connection destination wireless station, and the upper connection destination wireless station is selected. A wireless station that has received a connection-disabled signal from a station similarly notifies the slave wireless station of the connection-disabled signal and selects a new higher-level connection-destination wireless station.

[0024] The invention according to claim 11 to 20 shows a configuration of a radio station corresponding to the multi-hop wireless network of claim 1-10.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiments of the Invention According to Claims 1, 2, 11 and 12 ) FIG. 2 shows an embodiment of a wireless station which constitutes a multi-hop wireless network of the present invention. In the figure, the wireless station is
A hop number information acquisition unit 11 that acquires hop number information from a connectable wireless station, and an upper connection destination wireless station that selects a higher connection destination wireless station to be a relay destination from the connectable wireless stations according to the hop number information. The selection means 12 and the signal transfer means 13 for transferring the transmission signal or the signal received from the child radio station to the higher-order connection destination radio station or base station are provided.

FIG. 3 shows a basic processing procedure of the upper connection destination radio station selection means 12. First, when the wireless station can directly connect to the base station, the base station is selected as the higher-level connection destination wireless station (a1). Next, when it is not possible to directly connect to the base station, the hop number information of the connectable wireless stations acquired by the hop number information acquiring unit 11 is input (a2), and the hop number information of each connectable wireless station is compared. One of the connectable wireless stations having the smallest number of hops is selected from among them as the upper connection destination wireless station (a3). The upper connection destination wireless station selected here is notified to the signal transfer means 13 and becomes the transfer destination of the signal received from the child wireless station.

When the upper connection destination wireless station is selected (a3), the hop number plus 1 is recognized as the hop number of the own wireless station, and the hop number information is the hop of the connectable wireless station. The number information acquisition means 11 is notified (a4).
The hop count information acquisition unit 11 notifies the connectable wireless station of the hop count information by the method described below. Note that the hop number information acquisition unit 11 of the wireless station that can be directly connected to the base station recognizes the hop number of its own wireless station as 1,
The hop count information acquisition unit 11 of the other wireless stations recognizes the hop count of the upper connection destination wireless station selected by the upper connection destination wireless station selection unit plus one as the hop number of the own wireless station. Also, treat the base station as one wireless station,
The number of hops of the base station may be defined as 0.

FIG. 4 shows an example of a process in which a multi-hop wireless network is constructed by the wireless stations of the present invention.
In the figure, the hop number 1 is set in the hop number information acquisition means 11 of the wireless station M1 that can be directly connected to the base station S.
Next, when the wireless station M1 is determined, the wireless stations that can be connected to this wireless station select one wireless station M1 as a higher-level connection destination wireless station, thereby forming a tree shape for each wireless station M1. The wireless station M2 having a hop count of 2 is determined. Similarly, the wireless stations M3, M4, ..., Mk are sequentially determined. Here, Mk indicates a wireless station whose number of hops is k.

Now, it is assumed that the radio station Mx newly enters the network. The wireless station Mx selects one wireless station M2 having the smallest number of hops from the wireless stations M2, M3, and M4 that are connectable wireless stations, and selects this as the higher-level connection destination wireless station. As a result, the number of hops of the wireless station Mx becomes 3, and one wireless station Mx is set as the higher-level connection destination wireless station.
2 will be connected. In this way, each wireless station determines only one upper connection destination wireless station. As a result, each wireless station is connected to the upper connection destination wireless station, and a multi-hop wireless network is formed between the base station and each wireless station, with the base station as the highest-level station.

FIG. 5 shows a basic processing procedure of the signal transfer means 13. FIG. 5A shows a processing procedure of the signal transfer means 13 in the transmission source wireless station. When the transmission signal addressed to the base station is generated (b1), the signal transfer means 13 in the transmission source wireless station transmits the transmission signal to the higher-level connection destination wireless station (b2). FIG. 5B shows a processing procedure of the signal transfer means 13 in the relay wireless station. When the signal transfer means 13 in the relay wireless station receives the signal from the child wireless station (c1),
The received signal is transmitted to the upper connection destination wireless station (c2).

By such an operation of the signal transfer means 13 of the wireless station, a signal transmitted from a wireless station existing outside the communication area of the base station can also be transferred to the base station. The state of this signal transfer is shown in FIG.

In FIG. 6, when the wireless station Mk existing outside the communication area of the base station S transmits a signal to the base station, first, the signal is sent to the wireless station Mk-1 which is the upper connection destination wireless station. To send. The radio station Mk-1 that received this signal
Similarly, the received signal is transferred to the wireless station Mk-2 which is the higher-level connection destination wireless station. Hereinafter, each wireless station transfers the received signal to the upper connection destination wireless station, and finally the wireless station M1 transmits the received signal to the base station S.
Forward the received signal to. When a signal is transmitted from the base station S to the wireless station Mk, the transfer can be performed by following this route in reverse.

By the above procedure, each wireless station can select the upper connection destination wireless station and autonomously construct the multi-hop wireless network with the base station as the highest station. In addition, since each wireless station selects the wireless station with the minimum number of hops from the connectable wireless stations as the upper connection destination wireless station, a multi-hop wireless network with the minimum number of hops is automatically constructed. . In addition, each wireless station transfers the signal received from the child wireless station to the higher-level connection destination wireless station, so that the signal transmitted from the wireless station existing outside the communication area of the base station is transmitted via one or more relay wireless stations. It is possible to automatically establish a relay path for transfer to the base station.

(Embodiment of the Invention According to Claims 8 and 18 ) In this embodiment, the hop count information acquisition means 11 of each radio station is used.
Sends a broadcast message incorporating the number of hops of its own wireless station (hereinafter referred to as "hop number message"), and also receives this hop number message to obtain the number of hops of connectable wireless stations. Is. When the base station similarly transmits the hop count message by broadcast, the hop count of the base station is defined as 0. It is assumed that the carrier for the hop count message is predetermined in this network.

FIG. 7 shows a hop number information acquisition means 1 of the wireless station.
1 shows the first embodiment of the processing procedure of 1 and the upper connection destination radio station selection means 12. In the figure, when the hop number information acquisition means 11 of each wireless station tries to acquire the hop number of the connectable wireless station, first, the search time t of the hop number message is set (d1), and the flag indicating the initial state is set. 0 is set (d2).

Next, while monitoring whether or not the search time t has elapsed (d3), the carrier for the hop number message is searched (d4) to determine whether or not a signal having a reception level equal to or higher than the threshold L is received. Judge (d5). When a signal whose reception level is equal to or higher than the threshold value L is received, this signal is demodulated to determine whether or not it is a hop number message (d.
6). The threshold value L is a criterion for judging whether or not the own wireless station can connect to the wireless station transmitting this signal, and is specifically the minimum reception level for selecting a connectable wireless station. On the other hand, when the reception level is less than the threshold L,
Search carrier for hop count message (d3, d4)
Return to.

If the received signal is a hop count message, the hop count and the source radio station ID are read from it to obtain the hop count of the connectable radio station (d7). On the other hand, when the received signal is not the hop count message, the search for the hop count message carrier (d3, d
Return to 4). Next, it is determined whether or not the flag is 0 as to whether or not the acquired number of hops of the connectable wireless station is the first (d8). Since the flag is 0 at the beginning, the acquired hop number of the connectable wireless station is stored (d9), the flag 1 is set (d10), and the process returns to the hop number message carrier search (d3, d4).

When the next hop number message is received, it becomes No at d8 due to the flag 1 and is compared with the hop number of the connectable wireless station already stored (d11). If the newly acquired connectable wireless station hop count is less than the stored hop number, the stored connectable wireless station hop count is deleted and the newly acquired connectable wireless station hop count. Is stored (d12). On the other hand, if the newly acquired hop count of the connectable wireless station is greater than or equal to the stored hop count, the stored hop number of the connectable wireless station is left unchanged and the hop count message carrier is re-established. Return to search (d3, d4). If the number of hops of the newly acquired connectable wireless station is equal to the stored number of hops, the number of hops of the newly acquired connectable wireless station may be replaced, or the reception levels may be compared. The larger one may be selected and stored. As a result, the minimum hop count of the acquired connectable wireless stations is always stored.

During the search, it is constantly monitored whether or not the search time t has been exceeded since the start of the search (d3).
If the search time t has not elapsed, the search for the hop count message carrier is continued (d4). On the other hand, when the search time t has elapsed, the search for the hop count message carrier is terminated, and it is determined that the currently stored hop count of the connectable wireless station is the minimum (d1).
3).

By the above processing, each wireless station can recognize the wireless station having the minimum hop number from the hop number acquired from the hop number message of the connectable wireless station. Then, this wireless station is selected as the upper connection destination wireless station (see FIG. 3).
A3). For a wireless station that has been able to select one upper connection destination wireless station from the connectable wireless stations, add 1 to the number of hops of the upper connection destination wireless station as the number of hops of its own wireless station, and incorporate that number of hops. Then, the hop count message is transmitted by broadcast (a4 in FIG. 3).

(The hop count information acquisition according to claims 1 and 11
Embodiment of Obtaining Means ) In this embodiment, the hop count information obtaining means 11 of each wireless station is used.
However, at the transmission timing based on the number of hops of its own wireless station, a notification message (hereinafter "hop number timing message"
Is transmitted in a broadcast manner, and the hop count of the connectable wireless station is recognized based on the reception timing of this hop count timing message. When the base station similarly broadcasts the hop count timing message at a predetermined transmission timing, the hop count of the base station is defined as 0 and the transmission timing is set accordingly. The carrier for the hop count timing message is assumed to be predetermined in this network.

FIG. 8 shows an example of the timing when the base station and each wireless station transmit the hop count timing message. In the figure, the time axis is the broadcast time zone L in which the base station and each wireless station transmit the hop count timing message.
Then, the base station and each wireless station are divided into a notification time interval D in which no hop count timing message is transmitted, and this is repeated in a notification cycle T. However, the notification time interval D needs to be set larger than the notification time zone L.

The broadcast time zone L is divided into each layer broadcast time zone in which wireless stations having the same hop count transmit a hop count timing message. For example, only the base station can transmit the hop count timing message P0 in the first layer broadcast time zone, only the wireless station having the hop count of 1 can transmit the hop count timing message P1 in the next layer broadcast time zone, and so on. Number of hops for each layer announcement time zone 2,
Only the wireless stations of 3, ...
2, P3, ... Can be transmitted. The base station and each wireless station transmit a hop count timing message in each broadcast period T in each layer broadcast time zone corresponding to each hop count.

FIG. 9 shows a hop count information acquisition unit 1 of the wireless station.
2 shows a second embodiment of the processing procedure of 1 and the upper connection destination radio station selection means 12. In the figure, when the hop count information acquisition unit 11 of each wireless station tries to acquire the hop count of a connectable wireless station, a flag 0 indicating the initial state is set (f1), and the reception confirmation of the hop count timing message is confirmed. The number of times N is set (f2).

Next, the carrier for the hop count timing message is searched (f3), and it is determined whether or not a signal having a reception level equal to or higher than the threshold L is received (f4). When a signal whose reception level is equal to or higher than the threshold L is received, this signal is demodulated and it is determined whether or not it is a hop count timing message (f5). The threshold value L is a criterion for judging whether or not the own wireless station can connect to the wireless station transmitting this signal, and is specifically the minimum reception level for selecting a connectable wireless station. On the other hand, when the reception level is less than the threshold value L, or when the received signal is not the hop count timing message, the process returns to the search for the hop count timing message carrier (f3).

When the received signal is the hop count timing message, it is determined whether the flag is 0 (f
6). Since the flag is 0 at the beginning, the current time is set as the time T ₀ when the hop count timing message is first received (f7), and the transmission source radio station ID is acquired from the received hop count timing message and stored (f8). ). Next, the flag 1 is set (f9), and the received hop count timing message is set to n = 1, which indicates that the hop count timing message was received first in the broadcast time zone L and the hop count timing message was received for the first time. (F10), and again searches for carrier for hop count timing message (f3)
Return to.

When the next hop count timing message is received, it becomes No at f6 due to flag 1 and the reception time T of the previously received hop count timing message is received.
It is determined whether the elapsed time from ₀ is equal to or longer than the notification time zone L (f11). If this elapsed time is not equal to or longer than L (No in f11), it is determined that the received hop count timing message is not the first received in the broadcast time zone L, the reception is ignored, and the hop count timing message is received again. Return to search for carrier (f3). On the other hand, if the elapsed time from the previous reception time T ₀ is L or more (Yes in f11)
s), it is determined that the received hop count timing message is the first reception in the broadcast time zone L, and the following processing is performed.

First, the time T ₀ is reset to the current time (f
12), the transmission source wireless station ID is acquired from the received hop count timing message (f13), and this transmission source wireless station ID
It is determined whether or not the transmission source wireless station IDs stored as are the same (f14). If they match,
The received hop count timing message is the broadcast time zone L.
Since it was the first message received in the above, and the previous hop count timing message was received again in this notification period, 1 is added to n (f15), and n reaches the confirmation count N. It is determined whether or not (f16). If n has not reached the confirmation number N, the process returns to the search (f3) of the carrier for the hop number timing message. on the other hand,
If n has reached the confirmation count N, it is determined that the received hop count timing message is the first received in the broadcast time zone L, and the stored transmission source radio station ID can be connected. It is recognized that the wireless station has the minimum number of hops (f17).

When the source wireless station ID and the stored source wireless station ID do not match (No in f14), the received hop count timing message is different from the previous one and the previous notification time period It can be recognized that the message is received at a timing different from the hop count timing message received first in L. Therefore, the stored transmission source wireless station ID is erased, and the transmission source wireless station ID read from the hop number timing message just received is newly stored (f18). After that, it is initialized to n = 1 (f1
9) Then, the process returns to the search (f3) of the carrier for the hop count timing message.

FIG. 10 shows a specific operation example of the second embodiment. In the figure, in the first notification cycle Ta, the hop count timing messages P3 and P4 are continuously received at the timing corresponding to the hop counts 3 and 4, but P3 is the first one received in the notification time zone L. Yes, the connectable wireless station is stored as a wireless station with the minimum number of hops (f
8). Then, P4 that is continuously received is ignored since it is within the notification time zone L from the reception time T _{0 of} P3 (f
No in 11).

Next, the hop count timing message received from the reception time T _{0 of} P3 in the broadcast time zone L or more is monitored. That is, it is monitored whether or not the hop count timing message is received in the next broadcast cycle Tb, and here, the hop count timing message P corresponding to the hop count 2 is received.
Since 2 is received, the connectable wireless station is stored as a wireless station having the minimum number of hops (Yes in f11, f18). P3 and P4 in the notification period Tb are ignored (N in f11)
o).

Next, the hop count timing message received in the broadcast time zone L or more from the reception time T _{0 of} P2 is monitored. That is, in the next notification cycle Tc, it is monitored whether or not the hop count timing message is received, and here, P2 is received again (Yes in f11, Yes in f14).
When this P2 is similarly received N times, the connectable wireless station that has transmitted P2 is determined as the wireless station having the minimum hop count (f17).

Through the above processing, each wireless station monitors the reception timing of the hop count timing message, and the wireless station that first transmitted from the connectable wireless stations in the broadcast time zone L, that is, the hop count is the smallest. Can recognize wireless stations. Further, by providing the number of confirmations, it is possible to confirm the wireless station that first transmitted the hop count timing message within the notification time period, a plurality of times. Then, this wireless station is selected as the upper connection destination wireless station (see FIG. 3).
A3).

In the wireless station that has been able to select one upper connection destination wireless station from the connectable wireless stations, the hop number of the own wireless station is obtained by adding 1 to the number of hops of the upper connection destination wireless station, and the hop The hop count timing message is transmitted by broadcast at the transmission timing corresponding to the number (a4 in FIG. 3). This specific processing procedure will be described with reference to FIG.

In FIG. 11, when each wireless station selects an upper connection destination wireless station (g1), based on the reference time O, the upper connection destination wireless station transmits the hop count timing message in each layer broadcast time zone. It is judged whether it is done (g2). This determination is based on the fact that if each wireless station has previously recognized the time length of each layer broadcast time zone, the time when the hop count timing message is received from the upper connection destination wireless station is measured from the reference time O and the time length is calculated. It is possible by calculating the double. If each layer broadcast time zone in which the upper-level connection destination wireless station is transmitting the hop count timing message is known, the hop count timing message of the own wireless station is transmitted in each subsequent layer broadcast time zone (g3).

When there are a plurality of wireless stations that transmit the hop number timing message in the same layer broadcast time zone, the hop number timing message of the own wireless station is transmitted at a timing when it is not transmitted from another wireless station due to carrier sense or the like. To send. As a result, each wireless station can transmit a hop number timing message at a transmission timing (each layer broadcast time zone) corresponding to the hop number, and notify the connectable wireless station of information corresponding to the hop number. .

In this embodiment, each wireless station can recognize the wireless station having the minimum hop number among the connectable wireless stations only by adjusting the transmission timing of the broadcast message by each wireless station. Therefore, even if the number of hops cannot be incorporated in the broadcast message, it can be applied to any communication system in which each wireless station can recognize the reference time O of the broadcast message. For example, like PHS,
It can be applied to a communication system in which each wireless station is synchronized with an existing broadcast message in advance.

(Embodiment of the Invention According to Claims 9 and 19) In this embodiment, the hop count information acquisition means 11 of each radio station is used.
Sends a signal requesting the connectable wireless station to notify its hop count information (hop count message, hop count timing message), and the connectable wireless station receiving this request signal indicates the hop count of its own wireless station. A signal for responding information is transmitted to the connectable wireless station that has requested the information, and the wireless station that has received this response signal acquires the hop count information of the connectable wireless station.

FIG. 12 shows a third embodiment of the processing procedure of the hop count information acquisition means 11 and the upper connection destination radio station selection means 12 of the radio station of the present invention. In the figure, when the hop number information acquisition means 11 of each wireless station tries to acquire the hop number information of a connectable wireless station, first, a hop number information request signal is transmitted to neighboring wireless stations in a broadcast manner. (H
1). The peripheral wireless station that has received the hop count information request signal determines whether the reception level is equal to or higher than the threshold L (i1). The wireless station that has received the hop count information request signal when the reception level is equal to or higher than the threshold value L becomes a connectable wireless station to the source wireless station (i2). The threshold value L is a criterion for judging whether or not the own wireless station can connect to the wireless station transmitting this signal, and is specifically the minimum reception level for selecting a connectable wireless station.

Hop number information acquisition means 1 of connectable wireless stations
1 transmits a response signal for notifying the source wireless station of the hop number information of its own wireless station (i3). The response signal may be a hop count message incorporating the hop count, or may be a hop count timing message transmitted at a transmission timing corresponding to the hop count.

The hop number information acquisition means 11 of the wireless station that has transmitted the hop number information request signal can receive the response signal to establish connection by the configuration shown in the first embodiment or the second embodiment. The wireless station with the minimum number of hops is recognized from the wireless stations (h2).

Through the above processing, each wireless station can recognize the wireless station with the smallest hop number among the connectable wireless stations. Then, this wireless station is selected as the upper connection destination wireless station (a3 in FIG. 3). A wireless station that has been able to select one upper connection destination wireless station from the connectable wireless stations recognizes the hop number of the upper connection destination wireless station plus one as the hop number of its own wireless station, and hop number information. In response to the request signal, the connectable wireless station broadcasts the hop number information (a4 in FIG. 3).

In the present embodiment, the message notifying the hop number is transmitted only when each wireless station receives the hop number information request signal. Therefore, unlike the first or second embodiment described above, it is not necessary to constantly transmit the signal for notifying the hop number information in a broadcast manner, so that the traffic can be suppressed.

In the embodiment of the processing procedure of the hop number information acquisition means 11 of the wireless station and the upper connection destination wireless station selection means 12 shown above, a new wireless station newly joining the multi-hop wireless network can be connected to a wireless connection. It can be applied when trying to obtain hop count information of a station ( Claims)
3,10,13,20 ). As a result, the upper connection destination wireless station for the new wireless station is determined, and it becomes possible to enter the multi-hop wireless network. Further, it may be applied when each wireless station tries to acquire the hop count information of the connectable wireless station at a predetermined timing after constructing the multi-hop wireless network. This makes it possible to reconstruct a multi-hop wireless network. Hereinafter, a characteristic processing procedure in the reconstruction of the multi-hop wireless network will be described.

(Embodiment of the Invention According to Claims 4 and 14 ) FIG. 13 shows the hop count information acquisition means 11 of the wireless station of the present invention.
And a fourth processing procedure of the upper connection destination radio station selection means 12
2 shows an embodiment of the present invention. In the figure, after each wireless station selects the upper connection destination wireless station (j1), the hop count information acquisition unit 11 searches again as a wireless station having the smallest hop count from the connectable wireless stations, as a time. The stop time Ts is set (j2). Next, when the search stop time Ts elapses (j3), the wireless station having the smallest number of hops is recognized again from the connectable wireless stations (j4). Then, it is determined whether or not the re-recognized wireless station having the minimum number of hops matches the current upper connection destination wireless station (j5). If they match, the upper connection destination wireless station is not changed and the search stop time Ts is set again (j2).

On the other hand, when the re-recognized minimum hop number wireless station and the current upper connection destination wireless station do not match, a connectable wireless station having a smaller number of hops than the upper connection destination wireless station has appeared. Then, the upper connection destination wireless station is switched to the wireless station with the smallest number of re-recognized hops (j6).

The method of re-recognizing the wireless station having the minimum hop number among the connectable wireless stations is the same as in the first embodiment.
The processing procedure shown in the third embodiment is adopted. Further, when the processing procedure shown in the first embodiment or the third embodiment is adopted, the number of hops of the re-recognized minimum hop radio station and the current hop of the upper connection destination radio station The numbers may be compared, and when the former is smaller, the upper connection destination wireless station may be switched to the wireless station having the smallest number of re-recognized hops.

Through the above processing, each wireless station can always select the wireless station having the minimum hop number among the connectable wireless stations as the upper connection destination wireless station. Therefore, when a new wireless station enters the network, if the number of hops of the new wireless station is smaller than the number of hops of the upper connection destination wireless station of its own wireless station, this wireless station autonomously connects to the upper layer. The destination wireless station can be switched to the new wireless station. In this way, even when a new wireless station enters this network, or when the upper connected wireless station changes due to the movement of wireless stations, the star-type multi-hop wireless network with the minimum number of hops is also used. Can be rebuilt.

(Embodiment of the Invention According to Claims 5 and 15 ) In this embodiment, after the multi-hop wireless network is constructed, the upper connection destination is caused by the movement of the own wireless station or the movement or failure of the upper connection destination wireless station. A multi-hop wireless network is reconstructed by selecting a new upper connection destination wireless station from a wireless station that cannot connect to the wireless station. In this embodiment, it is assumed that each wireless station recognizes a child wireless station. As a specific recognition method, when each wireless station sets the upper connection destination wireless station, it notifies the upper connection destination wireless station of that fact, or the child wireless station when receiving a signal from the child wireless station. There are ways to check.

FIG. 14 shows a fifth embodiment of the processing procedure of the hop count information acquisition means 11 and the upper connection destination radio station selection means 12 of the radio station of the present invention. In the figure, when each wireless station cannot connect to the upper connection destination wireless station due to movement of its own wireless station, movement of the upper connection destination wireless station, or failure after selecting the upper connection destination wireless station (k1), This wireless station newly selects an upper connection destination wireless station (k2). The method of recognizing that the wireless station cannot connect to the upper connection destination wireless station is that the notification message from the upper connection destination wireless station cannot be received, or when the communication signal is transmitted to the upper connection destination wireless station. It should be recognized that the response signal is not returned. In addition, when the wireless station selects a higher-level connection destination wireless station, the method described in each of the above embodiments can be used. However, when the hop count information from the child radio station is received, this is discarded (k2).

By the above processing, the wireless stations that cannot connect to the upper connection destination wireless station due to movement or failure of the upper connection destination wireless station select the upper connection destination wireless station excluding the child wireless stations, and perform multi-hop. The wireless network can be reconstructed. As a result, it is possible to avoid a loop between the own wireless station and the child wireless station, which is caused by selecting the child wireless station as the upper connection destination wireless station. It is also possible for each wireless station to select a child wireless station (hereinafter referred to as "grandchild wireless station") as a new upper connection destination wireless station, but the wireless station with the smallest number of hops among the connectable wireless stations. In the configuration of the present invention in which is selected as the upper connection destination wireless station, the own wireless station and the grandchild wireless station cannot connect, and there is no fear of that. That is, in the present embodiment, even if each wireless station cannot connect to the higher-level connection destination wireless station, a new higher-level connection destination wireless station is selected while preventing a loop, and multi-hop wireless communication is autonomously performed between normal wireless stations. The network can be rebuilt.

(Embodiment of the Invention According to Claims 6 and 16 ) In this embodiment, after the multi-hop wireless network is constructed, the upper connection destination is caused by the movement of the own wireless station or the movement or failure of the upper connection destination wireless station. A multi-hop wireless network is reconstructed by selecting a new upper connection destination wireless station from a wireless station that cannot connect to the wireless station. In this embodiment, it is assumed that each wireless station recognizes a child wireless station.

FIG. 15 shows a sixth embodiment of the processing procedure of the hop count information acquisition means 11 and the upper connection destination radio station selection means 12 of the radio station of the present invention. FIG. 15 (a) is a processing procedure of a wireless station that cannot connect to a higher-level connection destination wireless station.
FIG. 15B shows the processing procedure of the child radio station.

In the figure, when each wireless station cannot connect to the upper connection destination wireless station due to movement of its own wireless station, movement of the upper connection destination wireless station, or failure after selecting the upper connection destination wireless station ( m1), this wireless station transmits, to the child wireless station, a connection disable signal indicating that the wireless station itself cannot connect to the upper connection destination wireless station (m2). Then, a new upper connection destination wireless station is newly selected (m3).

On the other hand, when the child wireless station receives the connection disable signal from the upper connection destination wireless station (n1), it is similarly informed to the child wireless station that the own wireless station cannot connect to the upper connection destination wireless station. A connection disable signal is transmitted (n2). And
A new upper connection destination wireless station is selected (n3). Similarly, the wireless station that has received the connection disable signal from the upper connection destination wireless station transmits the connection disable signal to its child wireless station and selects a new upper connection destination wireless station. In addition, when the wireless station selects the upper connection destination wireless station, the method described in each of the above embodiments can be used.

When the wireless station cannot connect to the upper connection destination wireless station due to the movement or failure of the upper connection destination wireless station by the above processing, it is called as the child wireless station and the child wireless station together with the own wireless station. As described above, all the wireless stations under the control of the own wireless station perform the process of selecting a new upper connection destination wireless station. Thereby, the multi-hop wireless network can be reconstructed.

FIG. 16 shows a specific operation example of the sixth embodiment. In the figure, it is assumed that in the initial multi-hop wireless network, wireless stations Ma-1, Ma, Ma + 1, Ma + 2 were sequentially connected. Here, it is assumed that the wireless station Ma-1 and the wireless station Ma cannot be connected. When the wireless station Ma cannot connect to the wireless station Ma-1, the wireless station Ma and the wireless stations Ma + 1 and Ma + 2 under the wireless station Ma also newly select the upper connection destination wireless station. As a result, the wireless stations Ma and Ma + 2 cannot select a new upper connection destination wireless station, and the wireless station Ma +
It is assumed that only 1 is able to select a new upper connection destination wireless station Mb. At this time, the number of hops of the wireless station Ma + 1 is b + 1 and is represented as Mb + 1. Then, the wireless stations Ma, Ma + 2
Are wireless stations Mb + 1 as new upper connection destination wireless stations, respectively.
Is selected, the multi-hop wireless network is reconstructed as the wireless station Mb + 2.

As described above, not only the wireless station that cannot connect to the upper connection destination wireless station newly selects the upper connection destination wireless station, but also all the wireless stations under the upper connection destination wireless station do not select the upper connection destination wireless station. By reselecting, it is possible to dynamically reconstruct the multi-hop wireless network.

[0079]

As described above, the multi-hop wireless network and the wireless station of the present invention acquire the hop count information of the connectable wireless stations, and select one of the connectable wireless stations having the smallest hop number. Select the wireless station as the upper connection destination wireless station. Also, when the upper connection destination wireless station is selected, the hop number added with 1 is taken as the hop number of the own wireless station, and the hop number information is notified to each connectable wireless station. As a result, each wireless station can autonomously select a higher-level connection destination wireless station, and thus a multi-hop wireless network with the minimum number of hops can be autonomously constructed.

In addition, there is a wireless station that newly joins after the construction of the multi-hop wireless network by always selecting the wireless station with the minimum number of hops among the connectable wireless stations as the upper connection destination wireless station. Alternatively, even when the upper connection destination wireless station changes due to the movement of the wireless station, the multi-hop wireless network can be quickly reconstructed. When a wireless station leaves the network due to movement or failure, the wireless station that used this wireless station as the upper connection destination wireless station autonomously selects a new upper connection destination wireless station while avoiding the loop structure. By doing so, it is possible to reconstruct a multi-hop wireless network in which a loop structure does not occur. In addition, not only the wireless station that used the disconnected wireless station as the upper connection destination wireless station, but also all wireless stations under its control autonomously select a new upper connection destination wireless station, thereby dynamically Reconstruction is possible. Therefore, the robustness of the reconstruction of the multi-hop wireless network against the departure of the wireless station can be enhanced.

As described above, in the multi-hop wireless network and the wireless station of the present invention, a star-type multi-hop wireless network in which the base station with the minimum hop count is always autonomously the highest station regardless of whether the wireless station joins or leaves. Can be built.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration example of a star-type multi-hop wireless network.

FIG. 2 is a block diagram showing an embodiment of a wireless station forming the multi-hop wireless network of the present invention.

FIG. 3 is a flowchart showing a basic processing procedure of an upper connection destination wireless station selection unit 12.

FIG. 4 is a diagram showing an example of a process in which a multi-hop wireless network is configured by the wireless station of the present invention.

5 is a flowchart showing a basic processing procedure of the signal transfer means 13. FIG.

FIG. 6 is a diagram showing how a signal is transferred from a wireless station outside the communication area of the base station to the base station.

FIG. 7 is a flowchart showing a first embodiment of the processing procedure of the hop count information acquisition means 11 and the upper connection destination radio station selection means 12;

FIG. 8 is an example of timing of transmitting a hop count timing message of a base station and each wireless station.

FIG. 9 is a flowchart showing a second embodiment of the processing procedure of the hop count information acquisition means 11 and the upper connection destination radio station selection means 12.

FIG. 10 is a diagram showing a specific operation of the second embodiment.

FIG. 11 is a flowchart showing a transmission processing procedure of hop count information according to the second embodiment.

FIG. 12 is a flowchart showing a third embodiment of the processing procedure of the hop count information acquisition means 11 and the upper connection destination radio station selection means 12;

FIG. 13 is a flowchart showing a fourth embodiment of the processing procedure of the hop count information acquisition means 11 and the upper connection destination radio station selection means 12;

FIG. 14 is a flowchart showing a fifth embodiment of the processing procedure of the hop count information acquisition means 11 and the upper connection destination radio station selection means 12;

FIG. 15 is a flowchart showing a sixth embodiment of the processing procedure of the hop count information acquisition means 11 and the upper connection destination radio station selection means 12;

FIG. 16 is a diagram showing a specific operation example of the sixth embodiment.

[Explanation of symbols]

S base station M radio station 11 Hop count information acquisition means 12 Upper connection destination wireless station selection means 13 Signal transfer means

─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Eisuke Kudo 2-3-1, Otemachi, Chiyoda-ku, Tokyo Inside Nippon Telegraph and Telephone Corporation (72) Inventor Masashi Nakatsugawa 2-3-3, Otemachi, Chiyoda-ku, Tokyo No. 1 Inside Nippon Telegraph and Telephone Corporation (72) Inventor Akinori Shibuya 2-3-3 Otemachi, Chiyoda-ku, Tokyo No. 1 Inside Nippon Telegraph and Telephone Corporation (72) Tomoaki Ogawa 2-3-3 Otemachi, Chiyoda-ku, Tokyo No. 1 in Nippon Telegraph and Telephone Corporation (72) Inventor Masayoshi Nakayama 2-3-1, Otemachi, Chiyoda-ku, Tokyo Inside Nippon Telegraph and Telephone Corporation (56) Reference JP-A-9-83528 (JP, A) ( 58) Fields investigated (Int.Cl. ⁷ , DB name) H04B ^7/ 24-7/26 H04Q ⁷ /00-7/38

Claims (20)

(57) [Claims] 1. A base station and a plurality of wireless stations, each wireless station having a relay function, and a wireless station existing outside the communication area of the base station relays a predetermined wireless station to communicate with the base station. In a multi-hop wireless network, each of the wireless stations is a hop related to the number of relay wireless stations (hereinafter referred to as “the number of hops”) from another wireless station that can be directly connected (hereinafter referred to as “connectable wireless station”) to the base station. Hop number information acquisition means for acquiring the number information, when the base station can be directly connected to select the base station as a higher-level connection destination wireless station, if the base station can not be directly connected to the connectable wireless station The upper connection destination wireless station selection means for selecting, as a higher connection destination wireless station, one connectable wireless station having the minimum number of hops obtained from the hop number information, and a transmission signal or its own wireless station. Signal that is received from a lower-level wireless station selected as a higher-level connection-destination wireless station (hereinafter referred to as a "child wireless station"), or transferred to the higher-level connection-destination wireless station, or to the base station if directly connected to the base station. Transfer means, the hop count information acquisition means,
The broadcast message is sent at the transmission timing based on the number of hops of the own wireless station.
This message will be sent simultaneously with the broadcast message.
Depending on the reception timing of the
Multi-hop wireless , wherein each wireless station autonomously selects the upper connection destination wireless station and sets a relay path to the base station. network. 2. A hop count information acquisition unit of a wireless station that can be directly connected to the base station recognizes the hop count of its own wireless station as 1, and the hop number information acquisition unit of other wireless stations is the upper connection. The number of hops of the upper connection destination wireless station selected by the destination wireless station selection means is recognized as the number of hops of its own wireless station, and the number of hops of each wireless station along the relay path from the base station side is recognized. The multi-hop wireless network according to claim 1 , wherein the multi-hop wireless network is configured to sequentially add. 3. The hop count information acquisition means of a wireless station newly joining the network is connected to the wireless station newly connected to the hop count information acquisition means.
Hop depending on the reception timing of the notification message
Claim 1, characterized in that the configuration for acquiring the number information
The multi-hop wireless network described in. 4. The hop count information acquiring means and the upper connection destination radio station selecting means of the radio station construct the multi-hop radio network, and thereafter, the hop count is the smallest among the connectable radio stations at a predetermined timing. One connectable wireless station is selected, and if the connectable wireless station and the current upper connected wireless station do not match, the connectable wireless station is selected as a new upper connected wireless station. The multi-hop wireless network according to any one of claims 1 to 3 , characterized in that: 5. The hop count information acquisition means and the upper connection destination wireless station selection means of the wireless station, when a connection with the upper connection destination wireless station is no longer possible after the multi-hop wireless network is constructed, It claims 1-3, wherein the number of hops, except the terminal radio station from among the connectable radio station is configured to select one of the connectable radio station having the minimum as the upper connection-destination radio station Which of
Multi-hop wireless network of crab described. 6. A base station and a plurality of radio stations, each radio station having a relay function, and a radio station existing outside the communication area of the base station relays a predetermined radio station to communicate with the base station. In a multi-hop wireless network, each of the wireless stations is a hop number information acquisition unit that acquires hop number information regarding the hop number from the connectable wireless station, and if a direct connection to the base station is possible, a base station is connected to an upper layer. When it is not possible to directly connect to the base station by selecting it as the destination wireless station, one connectable wireless station having the minimum hop number obtained from the hop number information is selected from the connectable wireless stations as the upper connection destination wireless station. When the upper connection destination wireless station selection means to be selected as a station and the transmission signal or the signal received from the child wireless station can be directly connected to the upper connection destination wireless station or the base station And a signal transfer means for transferring to the earth station, the hop number information acquiring means and host connection-destination radio station selection
After the means to build a multi-hop wireless network
If the connection to the higher-level connection destination wireless station is no longer possible,
Is notified to the slave radio station by a signal indicating that connection is impossible.
However, after the notification, the ho
One connectable wireless station with the smallest number of connections
Selected as a wireless station, and from the upper-level connected wireless station
The wireless station that receives the connection disable signal will also be sent to the child wireless stations.
Informs the connection disabled signal and newly establishes a destination wireless connection
A multi-hop wireless network characterized by being configured to select stations . 7. The hop count information acquisition means of a wireless station that can be directly connected to the base station recognizes the hop count of its own wireless station as 1, and the hop count information acquisition means of other wireless stations is the upper connection. The number of hops of the upper connection destination wireless station selected by the destination wireless station selection means is recognized as the number of hops of its own wireless station, and the number of hops of each wireless station along the relay path from the base station side is recognized. 7. The multi-hop wireless network according to claim 6 , wherein the multi-hop wireless network is configured to sequentially add. 8. The hop count information acquisition means of the wireless station is
A notification message including the number of hops of its own wireless station is always transmitted as the hop number information, and the notification message is received to obtain the hop number information of the connectable wireless station. 6. The method according to claim 6,
Or a multi-hop wireless network according to claim 7 . 9. The hop count information acquisition means of the wireless station is
A connectable radio that transmits a signal requesting to notify the connectable radio station of the hop count information, and the connectable radio station that has received the request signal requests a signal that responds to the hop count information of its own radio station 8. The multi-hop wireless network according to claim 6 or 7 , wherein the wireless station which transmits the response signal to the station acquires the hop count information of the connectable wireless station. 10. A hop count information acquisition unit for a wireless station newly joining the network is provided from the connectable wireless station.
Receives the notification message and obtains hop count information
Or send a request signal to the connectable wireless station
Receives the response signal according to and acquires the hop count information
Multi-hop wireless network <br/> claim 8 or claim 9, characterized in that it is configured. 11. A base station and a plurality of wireless stations,
In a wireless station of a multi-hop wireless network in which each wireless station has a relay function, a wireless station existing outside the communication area of the base station relays a predetermined wireless station to communicate with the base station, from the connectable wireless station to the A hop number information acquisition unit that acquires hop number information regarding the number of hops, when the base station can be directly connected, the base station is selected as an upper connection destination wireless station, and when the direct connection cannot be made to the base station, the connection is made. Outer connection destination wireless station selection means for selecting, as an upper connection destination wireless station, one connectable wireless station having the smallest number of hops obtained from the hop number information from the available wireless stations; signal to the superordinate destination radio station received from a station, or if the direct connection to the base station and a signal transfer means for transferring to the base station, collected the hop count information Means, as the hop count information
The broadcast message is sent at the transmission timing based on the number of hops of the own wireless station.
This message will be sent simultaneously with the broadcast message.
Depending on the reception timing of the
A wireless station of a multi-hop wireless network, characterized in that the wireless station is configured to acquire the number of packets . 12. The hop count information acquisition means of a wireless station that can be directly connected to the base station recognizes the hop count of its own wireless station as 1, and the hop count information acquisition means of other wireless stations is the upper connection. The multi-hop wireless network according to claim 11 , wherein the destination wireless station selection means recognizes the hop number of the higher-level connection destination wireless station selected by 1 as the hop number of the own wireless station. Radio station. 13. A hop count information acquisition unit for a wireless station newly joining the network is provided from the connectable wireless station.
Depending on the reception timing of the notification message, the
Claims characterized in that it is configured to acquire information on the number of groups
11. The wireless station of the multi-hop wireless network according to item 11 . 14. The hop count information acquiring means and the upper connection destination radio station selecting means minimize the hop count among the connectable radio stations at a predetermined timing after constructing a multi-hop radio network. One connectable wireless station is selected, and if the connectable wireless station and the current upper connected wireless station do not match, the connectable wireless station is selected as a new upper connected wireless station. The wireless station of the multi-hop wireless network according to any one of claims 11 to 13 . 15. The hop count information acquiring means and the upper connection destination radio station selecting means can reconnect to the upper connection destination radio station if the connection cannot be established after the multi-hop wireless network is constructed. 14. A configuration in which one connectable wireless station having the smallest number of hops is selected as an upper connection destination wireless station from the wireless stations, excluding the child wireless stations, is selected .
Radio station of a multi-hop wireless network according to. 16. A base station and a plurality of wireless stations,
In a wireless station of a multi-hop wireless network in which each wireless station has a relay function, a wireless station existing outside the communication area of the base station relays a predetermined wireless station and communicates with the base station, from the connectable wireless station to the A hop number information acquisition unit that acquires hop number information regarding the number of hops, and if the base station can be directly connected, selects the base station as a higher connection destination wireless station, and if the direct connection to the base station is not possible, the connection is performed. Higher-destination wireless station selection means for selecting one connectable wireless station having the smallest hop number obtained from the hop number information as a higher-destination wireless station from the possible wireless stations, and a transmission signal or the slave wireless station. signal to the superordinate destination radio station received from a station, or if the direct connection to the base station and a signal transfer means for transferring to the base station, collected the hop count information Means and upper connection target radio station selection
After the means to build a multi-hop wireless network
If the connection to the higher-level connection destination wireless station is no longer possible,
Is notified to the slave radio station by a signal indicating that connection is impossible.
However, after the notification, the ho
One connectable wireless station with the smallest number of connections
Selected as a wireless station, and from the upper-level connected wireless station
The wireless station that receives the connection disable signal will also be sent to the child wireless stations.
Informs the connection disabled signal and newly establishes a destination wireless connection
A wireless station of a multi-hop wireless network, characterized in that the station is selected . 17. The hop count information acquisition means of a wireless station that can be directly connected to the base station recognizes the hop count of its own wireless station as 1, and the hop count information acquisition means of other wireless stations is the upper connection. 17. The multi-hop wireless network according to claim 16 , wherein the destination wireless station selection means recognizes a value obtained by adding 1 to the number of hops of the upper connection destination wireless station selected as the number of hops of the wireless station itself. Radio station. 18. The hop count information acquiring means always broadcasts a broadcast message including the hop count of its own wireless station as the hop count information, and receives the broadcast message to receive the connectable radio. claim 16 or, characterized in that it is configured to acquire the hop number information of stations
The radio station of the multi-hop radio network according to claim 17 . 19. The hop count information acquisition means transmits a signal requesting to notify the connectable radio station of the hop count information, and the connectable radio station receiving the request signal is the own radio station. transmitted to the connectable radio station that requested a signal responsive hop number information, or claim 16, wherein the radio station which has received the response signal is configured to acquire the hop number information of the connectable radio station The radio station of the multi-hop radio network according to claim 17 . 20. The hop number information acquiring means of a wireless station newly joining the network receives the notification message from the connectable wireless station to acquire the hop number information, or from the connectable wireless station. The hop count information is acquired according to the reception timing of the notification message, or the hop count information is acquired by transmitting a request signal to the connectable wireless station and receiving a response signal corresponding to the request signal. The wireless station of the multi-hop wireless network according to claim 18 or 19 .