JP2002325273A - Radio communication system, radio communication method, and radio station - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio communication system capable of packet transmission which ensures a low delay, low delay fluctuations, a high throughput, and a QoS in a multi-hop radio communication. SOLUTION: A radio station has a plurality of channels, and functions of a master station which controls transmission rights for each channel and a slave station which is under a control of the master station. When the radio station functions as the master station, it transmits a signal in accordance with the control of its own station, and when it functions as the slave station, it transmits a signal under the control of the master station. Any of the radio stations communicates with all other radio stations directly or via one or more other radio stations. For each radio channel, a centrally controlled access scheme and an autonomously distributed access scheme are split in accordance with time for application, thus communication is executed. In the case of the centralized control, the master station is determined for every channel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless communication system in a multi-hop wireless communication network constituted by a plurality of wireless stations.

[0002]

2. Description of the Related Art In a wireless packet transmission method such as a wireless LAN and a mobile communication system, a CSMA / CA (Carrier Sense Multiple Access Wi-Fi) is used as an autonomous distributed access method.
th Collision Avoidance) method. In this scheme,
Before transmitting a data packet, it is checked whether or not a channel scheduled to be transmitted for a certain period of time is free, so that packet collision can be reduced. The above method is based on ANSI
/ IEEE Std802.11 Wireless LAN Medium Access Control
As described in (MAC) and Physical Layer (PHY) specification, it has been adopted as the MAC protocol of the IEEE802.11 standard.

[0003]

However, if the autonomous decentralized CSMA / CA method is applied to a multi-hop wireless communication network, contention occurs on each link and retransmission must be performed. Large delay fluctuations occur. Also, when a wireless channel is used by another wireless station on an intermediate link, transmission cannot be performed until the wireless channel is free, so that the delay increases and the throughput deteriorates.

On the other hand, Poll which is a centralized control type access method
The Polling / CSMA method, which is an access method that applies the ing method or the centralized control type access method and the autonomous decentralized access method in a time-divided manner, has the effect that packet collisions occur because the master station manages the transmission of slave stations. No delay occurs, delay and delay fluctuation are reduced, throughput is improved, and QoS (Quality of Service
e) can be guaranteed. However, in a multi-hop wireless network, since a single master station cannot manage all the wireless stations, there is a problem that the conventional Polling scheme and Polling / CSMA scheme cannot be applied to the multi-hop wireless network.

[0005] The present invention improves the above-mentioned problems, and an object of the present invention is to provide a multi-hop wireless communication network.
An object of the present invention is to provide a wireless communication system for packet transmission that realizes low delay, low delay fluctuation, high throughput, and high QoS guarantee.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, an aspect of the present invention comprises a plurality of radio stations, each radio station having at least one radio channel for packet radio communications, and In a wireless communication system capable of communicating with other wireless stations directly or via at least one wireless station, each wireless station communicates with a nearby wireless station on a centralized control access basis for each wireless channel. Or, perform communication by autonomous decentralized access, and in the case of centralized control access, each wireless station adaptively controls a transmission right for each wireless channel and transmits a signal according to its own control, or a master station, or A wireless communication system that operates as a slave station that transmits a signal according to control of a master station, and wherein the centralized control access and the autonomous decentralized access are performed in a time-divided manner for each wireless station and for each wireless channel. A.

Preferably, from one radio station A ₁ to another radio station A _n (n is an integer of 2 or more), radio stations A ₂ , A ₃ ,.
A _k, when _{A k + 1, ... A n} -1 (k is the n-1 an integer 2 or more) transmit signals to the relay, the radio station A _k is A _k and A _{k + 1} of A radio channel between the master station and the slave station, or _Ak and _{Ak + 1}
A signal is transmitted via a wireless channel having a relationship between slave stations controlled by a common master station.

Preferably, when the radio station operates as a master station for centralized control access on a certain channel, the master station transmits a "start notification packet" indicating the start of the centralized control access, and the start notification packet is transmitted to the parent station. The start notification includes the address of the station, the addresses of all the slave stations belonging to the master station, and the time until each slave station transmits a “communication request packet” to the master station in response to the start notification packet. Each slave station that has received the packet transmits a “notification request packet” to the master station at the time specified by the start notification packet.

Preferably, when a radio station operating in a relationship between a master station and a slave station for centralized control access on a certain channel ends the centralized control access and switches to autonomous decentralized access, the master station performs centralized control access. The end notification packet indicates the end time of the centralized control access, the time until the next start notification packet is transmitted, and the slave station that has received the end notification packet. The slave station receiving the end notification packet includes information on whether or not the end notification packet should be relayed to another slave station, and the slave station receiving the end notification packet transmits the “end notification packet” at the end time notified by the end notification packet to the master station. To switch from centralized control access to autonomous decentralized access.

Preferably, each radio station performs carrier sensing for a certain period of time for each channel, and when receiving a start notification packet from the master station, operates as a slave station subordinate to the master station on the channel, When a communication request packet from a slave station is received without receiving a start notification packet from the station, the station operates as a transmission prohibiting station that prohibits transmission during the centralized control access by the master station in the channel. After that, when an end notification packet is received from the master station or the slave station, transmission is performed by autonomous distributed access until the time of the next start notification packet described in the end notification packet, and a start notification packet from the master station is transmitted. When the communication request packet is not received and the communication request packet is not received,
It operates as a master station for centralized control access on the channel.

Preferably, when the first wireless station does not receive the start notification packet from the master station and does not receive the communication request packet, the second wireless station connected to the wireless station via another channel is not required. The first radio station operates as a master station on the channel and the second radio station operates as a slave station subordinate to the master station, or
Wireless station operates as a master station, and the first wireless station operates as a slave station subordinate to the master station.

Another feature of the present invention is that in a wireless station device in a wireless network constituted by a plurality of wireless stations, each wireless station device has at least one channel for wireless communication, and each wireless station device has The wireless station device is operable as a master station having jurisdiction over a transmission right in centralized control access, a slave station managed by the master station, or a transmission prohibition station, and is also operable with autonomous distributed access.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing a channel configuration for packet relay in the present invention. Note that the method of determining the route between wireless stations is the AODV method (Adhoc On-demand Dista
This is known as a nce vector.

Using four wireless channels from channel a to channel d, the wireless station 1 as a transmitting station is relayed in the order of wireless station 2, wireless station 3,..., Wireless station 6, and wireless station 7 as a destination station. It shows the case of transmitting up to. Each radio station is a master station, a slave station, or a transmission prohibition station in centralized control access for each channel. As shown in FIG. 1, when performing communication with a wireless station 2, a wireless station 1 uses a channel c or a channel d having a relationship between a master station and a slave station between the wireless station 1 and the wireless station 2 to perform centralized control. The communication is performed by the access method described above. Channel c
, The wireless station 1 is a slave station and the wireless station 2 is a master station. On the other hand, in the channel d, the wireless station 1 is a master station and the wireless station 2 is a slave station.
Similarly, when the wireless station 2 communicates with the wireless station 3, the channel b having a relationship between the master station and the slave station between the wireless station 2 and the wireless station 3.
Alternatively, communication is performed by a centralized control type access method using channel c. Thereafter, similarly, communication is performed up to the wireless station 7 using a channel having a relationship between the master station and the slave station. After all,
Communication from the wireless station 1 to the wireless station 7 can be performed by a centralized access method, and QoS between the wireless station 1 and the wireless station 7 can be guaranteed.

The above embodiment is an embodiment in which centralized control access is performed on all links. In some links,
Communication may be performed by autonomous decentralized access that has no relationship between the master station and slave stations.

Next, an example of centralized control access will be described with reference to FIGS. 2A and 2B. In this embodiment, there are slave stations 22, 23, and 24 within the service area 61 of the master station 21.

The radio station 21 performs a centralized control cycle with respect to the slave stations (the radio stations 22, 23 and 24) subordinate to the radio station 21 on the channel in which the radio station 21 operates as a master station. A start notification packet 101 indicating the start of the communication is transmitted. The start notification packet 101 describes the addresses of the wireless stations 21, 22, 23 and 24 and the time at which each slave station should transmit a communication request packet.

The wireless station 22 sends a start notification packet from the wireless station 21.
When 101 is received, a communication request packet 201 is sent to the wireless station 21.
Send Next, the wireless station 23 transmits a communication request packet 202 to the wireless station 21. Next, the wireless station 24 transmits a communication request packet 203 to the wireless station 21.

The wireless station 21 first transmits a POLL packet 301 to the wireless station 22 after a lapse of time for completing reception of all communication request packets. The POLL packet is the same as the POLL packet in the known polling method, and includes a master station address and a slave station address. In response to the POLL packet 301, the wireless station 22 transmits a data packet 401 to the wireless station 21 and the wireless station 2
1 transmits a confirmation ACK for the data packet 401 and a POLL (ACK + POLL) packet 501 for the wireless station 23. In response, the wireless station 23 transmits a data packet 402.
When the transmission of the POLL packet to all the wireless stations is completed, the wireless station 21 transmits an end notification packet 601 indicating the end of the centralized control and an acknowledgment to the data packet 403 to the wireless stations 22, 24, and 24. I do. End notification packet
601 contains the end time of the centralized control access, and then the wireless station 21
The time until the next start notification packet is transmitted, and control information as to whether or not to relay the end notification packet to another slave station are described, and the slave station performs autonomous distributed control until the above time elapses. Communication can be performed.

In the above embodiment, since the master station receives the communication request packet of the slave station before starting the polling, the master station can perform the polling according to the information. Further, it is possible to relay the end notification packet to a wireless station outside the circle 61 where the radio wave of the wireless station 21 does not reach.

Next, referring to FIGS. 3A and 3B, a sequence for relaying the end notification packet to outside the service area of the master station will be described. In FIG. 3B, the wireless station 31 is a master station, and its service area is indicated by a circle 71, in which a slave station
There are 32, 33, and 34.

The radio station 31 has a radio station 32, a radio station 33, and a radio station inside a circle 71 capable of receiving a signal transmitted from the radio station 31 in a channel in which the radio station 31 operates as a master station.
It is assumed that communication is performed with central control access to 34. Centralized control access (111, 311, 411, 511, 41
2, 512, 413) is the same as the embodiment of FIG. 2A. Radio station 3
Reference numeral 1 denotes an end notification packet 611 when the centralized control access (Polling) to the wireless station 32, the wireless station 33, and the wireless station 34 ends.
Is transmitted to the wireless station 32, the wireless station 33, and the wireless station.

The end notification packet 611 describes the addresses of the wireless stations 31, 32, 33 and 34 and control information for relaying the end notification packet to another slave station. Upon receiving the end notification packet 611 from the wireless station 31, the wireless station 32 transmits an end notification packet 612 within a circle 72 capable of receiving a signal transmitted from the wireless station 32. Radio station 33
The wireless station 34 also transmits the end notification packets 613 and 614 within the circles 73 and 74. Therefore, the end notification packet is sent to the wireless station.
It is possible to transmit to a radio station outside the 31 service area circle 71.

The relayed end notification packets 612, 613, 61
4 can also be received by the master station 31.

The radio stations inside circles 72, 73 and 74 and outside circle 71 in FIG. 3B cannot receive signals from master station 31, but receive signals from slave stations 32, 33 or 34. be able to. When the master station 31 is performing centralized control access, these wireless stations become transmission prohibited stations, and the centralized control access by the master station 31 ends, and an end notification packet is sent from the slave station (32, 33 or 34). Upon reception, communication can be performed with the slave station by autonomous decentralized access.

Referring to FIGS. 4A and 4B, when there are slave stations 42 and 43 within the area 83 of the master station 41,
A sequence for registering a new station 44 within the range 83 as a slave station of the master station 41 will be described.

It is assumed that the wireless station 41 communicates with the wireless station 42 and the wireless station 43 by centralized control access on a wireless channel in which the wireless station 41 operates as a master station.
Here, it is assumed that the wireless station 44 within the circle 81 capable of receiving the signal transmitted from the wireless station 41 turns on the power and newly starts communication on a channel in which the wireless station 41 operates as a master station.

Centralized control access by the master station 41 to the slave stations 42 and 43 (121,221,222,321,421,521,422,621)
Is the same as the sequence in FIG. 2A or FIG. 3A.

The new wireless station 44 performs carrier sense for a certain period of time, and upon receiving the start notification packet 121 from the wireless station 41, transmits a registration request packet 721 to the wireless station 41 (master station). The registration request packet includes the address of the own station, the address of the relay station if there is a relay station, and the address of the master station. The time at which the registration request packet 721 is transmitted may be after a random time, or may be a time specified by the master station 41 in advance. Upon receiving the registration request packet 721 from the wireless station 44, the wireless station 41 transmits a registration confirmation packet 821 to the wireless station 44 when the wireless station 44 can operate as a slave station of the wireless station 44. The registration confirmation packet includes the address of the own station, the address of the relay station if there is a relay station, and the address of the master station. Radio station 44 is a radio station
Upon receiving the registration confirmation packet 821 from 41, it operates as a slave station of the wireless station 41 on the channel thereafter. As described above, a new wireless station capable of receiving a signal transmitted from the master station can be registered in the master station.

Referring to FIGS. 5A and 5B, when the slave stations 52 and 53 are within the area 91 of the master station 51, the new station 54 outside the area 91 of the master station 51 is assigned to the master station 51. The registration sequence will be described.

The wireless station 54 that is outside the circle 91 that can receive the signal transmitted from the wireless station 51 and that is within the circle 93 that can receive the signal transmitted from the wireless station 53 is the parent station of the wireless station 51. In the above channel operating as a station, the wireless station 54 turns on the power.
It is assumed that communication is newly started.

The centralized control by the master station 51 on the slave stations 52 and 53 is the same as in FIGS. 2A, 3A and 4A. The new wireless station 54 performs the carrier sense for a certain period of time, and when the communication request packet 232 is received from the wireless station 53 without receiving the start notification packet 131 from the wireless station 51, the registration request packet 731 is sent to the wireless station 53 after a random time. Send. Radio station 53
Receives the registration request packet 731 from the wireless station 54,
When transmission is possible, a registration confirmation packet 831 is sent to the wireless station 54.
Send

In this case, the new radio station 54 is registered as a transmission prohibited station. Thereafter, upon receiving the end notification packet 632 from the wireless station 51, the wireless station 53 relays the end notification packet 633 to the wireless station 54. The end notification packet 633 describes the time until the wireless station 51 transmits the next start notification packet in the channel. Upon receiving the end notification packet 633 from the wireless station 53, the wireless station 54 can perform communication in an autonomous decentralized manner until the next start notification packet described in the end notification packet 633. As described above, transmission of a new radio station that cannot receive a signal transmitted from a master station and that can receive a signal transmitted from a slave station is prohibited, and when the centralized control by the master station is completed, the new radio station is terminated. Can recognize the end of the centralized control of the master station through the transmission of the slave station, and can perform communication using the autonomous decentralized method until the next centralized control is started.

FIG. 6 shows an example of the arrangement of radio channels according to the present invention. By performing the above-described sequence, a wireless channel is allocated to each wireless station as shown in FIG. FIG.
When a wireless channel is allocated to each wireless station as shown in FIG.
It is possible to perform communication from the transmitting station to the destination station using a centralized control type access method or an access method that applies a centralized control type access method and an autonomous decentralized access method in a time-divided manner. Guarantee can be realized.

FIG. 7 is a flowchart showing the operation when a new wireless station not participating in the centralized control access registers as a master station or a slave station in the centralized control access.

When there are a plurality of radio stations to be registered by a new radio station, the selection of which radio station to register depends on one or a combination of the following criteria A.

[0037]Standard A  (A1) Up to the gateway connected to the wired network
Are selected in the order of the wireless station with the smallest number of hops. (A2) Radio station with large received power in new radio station
Select in order. (A3) The wireless stations with the smaller interference amount are selected in order. (A4) A wireless station with a small number of already connected wireless stations
Select in order. (A5) Required C / I (Carrier to Interference Ratio)
In the order of the amount of interference that can be added until it does not fall below
To choose.

When the wireless station to be registered is not the master station, the selection of the new wireless station or the registered partner station as the master station depends on one of the following criteria B or a combination thereof.

[0039]Standard B  (B1) A new wireless station is set as a master station. (B2) The wireless station of the registration partner is the master station. (B3) In the case of a mobile radio station, the radio station with the larger battery capacity
Is the master station. (B4) Select a wireless station that uses a smaller number of channels
Be the master station. (B5) The wireless station with the smaller amount of interference is the master station.

In FIG. 7, a radio station to be newly registered performs carrier sensing for all frequency channels for a certain period of time (F1). If the received signal levels of the start notification packet, the transmission request packet, and the end notification packet exceed the threshold value as a result of performing the carrier sense, the information is written to the frequency channel and the connected wireless station table. In this table, the received power level from the radio station on the channel, the interference power level from other radio stations on the channel, and whether the radio station is operating as a master station managing the frequency on the channel Is written as whether it is operating as a slave station that is not the master station. As a result, it is detected whether or not there is a master station in the vicinity (F3). When a plurality of master stations are detected (F5), one master station is selected based on the criterion A (F7).

Next, it is determined whether or not the new wireless station can operate as a slave station on the channel of the selected master station, for example, by measuring whether or not the amount of interference is equal to or less than an allowable value ( F9, F15). If it can operate as a slave station, it is registered as a slave station (F11, F17), and the registration flow ends (F19).

If it is determined in F9 that the operation as a slave station is impossible, if the search for all master stations has not been completed (F13), F
9. The operations of F11 and F11 are repeated, and if a master station that can be registered as a slave station is detected, the master station is registered as a slave station.

When there are a plurality of master stations near the new registration station, and all the master stations want to register on each channel, they are registered as slave stations in F11 and then terminated (F1).
9) Instead of proceeding to F13, try registration with another master station by F9 and F11.

When a parent station is not detected in the vicinity by the carrier sense of F1, when it is determined that the operation as a child station is impossible in F15, and when all the parent stations are searched in F13, it is registered as a child station. If not, proceed to F21 to search for nearby wireless stations and their free channels. This search is performed by detecting a communication request packet or an end notification packet.
Here, when a plurality of wireless stations are detected, one wireless station is selected based on the criterion A.

If a nearby wireless station and a vacant channel are detected in F21, it is determined whether or not communication is possible using the vacant channel, for example, by measuring the amount of interference (F23). F
When it is determined that communication is possible in step 23, the process proceeds to step F29, in which whether the new wireless station is to be a master station or a slave station is determined based on the reference B, and registration is performed in step F17.

When it is determined in F23 that communication is impossible, it is determined whether communication with another wireless station through a channel is possible (F23, F25). If communication with all wireless stations is not possible on the channel, registration fails (F27).

[0047]

According to the present invention, when an autonomous decentralized access method is used in a multi-hop wireless packet communication network in which a plurality of wireless stations exist, delay, delay fluctuation and throughput are deteriorated, and QoS cannot be guaranteed. According to the present invention, by applying a centralized control access method or an access method in which a centralized control access method and an autonomous decentralized access method are time-divided and applied to multi-hop wireless packet communication using a plurality of channels, It is possible to determine a master station for performing centralized control for each channel, thereby reducing delay and delay fluctuation, improving throughput, and guaranteeing QoS.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a channel for packet relay in the present invention.

FIG. 2A is a first packet processing sequence example in the present invention.

FIG. 2B is an example of the arrangement of transmitting and receiving radio stations corresponding to FIG. 2A.

FIG. 3A is an example of a second packet processing sequence in the present invention.

FIG. 3B is an example of the arrangement of transmitting and receiving radio stations corresponding to FIG. 3A.

FIG. 4A is a third packet processing sequence example in the present invention.

FIG. 4B is an example of arrangement of transmitting and receiving radio stations corresponding to FIG. 4A.

FIG. 5A is a fourth packet processing sequence example in the present invention.

FIG. 5B is an example of the arrangement of transmitting and receiving radio stations corresponding to FIG. 5A.

FIG. 6 is an example of arrangement of wireless channels according to the present invention.

FIG. 7 shows a flow of an operation for registering a new wireless station in a network.

[Explanation of symbols]

 ad Radio channel 11-54 Radio station 61-93 Range of radio wave 101-131 Start notification packet 201-232 Communication request packet 301-331 POLL packet 401-432 Data packet 501-531 ACK + POLL packet 601-633 End Notification packet 711 to 731 Registration request packet 811 to 831 Registration confirmation packet

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hiroto Suda 2-3-1 Otemachi, Chiyoda-ku, Tokyo F-term in Nippon Telegraph and Telephone Corporation (reference) 5K033 BA08 CC01 DA01 DA19 5K067 AA13 BB21 CC04 CC08 DD17 EE02 EE06 EE10 HH31 JJ11

Claims (13)

[Claims] Claims 1. A plurality of wireless stations, each wireless station having at least one wireless channel for packet wireless communication, wherein each wireless station communicates directly with another wireless station or at least one wireless station. In a wireless communication system capable of communicating via a station, each wireless station communicates with a nearby wireless station for each wireless channel by centralized control access or autonomous decentralized access. Each radio station adaptively, for each radio channel, operates as a master station that controls a transmission right and transmits a signal under the control of its own station, or a slave station that transmits a signal under the control of the master station, A radio communication system wherein centralized control access and said autonomous distributed access are performed in a time-division manner for each radio station and for each radio channel. 2. A radio station A ₁ from another radio station A _n (n
, A ₂ , A ₃ ,... A _k , A _{k + 1} ,
.. A _n-1 (k is an integer of 2 or more and n-1 or less) when relaying and transmitting a signal, the radio station A _k is a master station and a slave station between A _k and A _{k + 1.} The wireless communication according to claim 1, wherein the signal is transmitted via a wireless channel having a relationship of (a) or a wireless channel having a relationship between slave stations controlled by a master station common to A _k and A _{k + 1.} system. 3. When a wireless station operates as a master station of centralized control access on a certain channel, the master station transmits a “start notification packet” indicating the start of centralized control access, and the start notification packet is transmitted to the master station. And the addresses of all slave stations belonging to the master station, and the time required for each slave station to transmit a “communication request packet” to the master station in response to the start notification packet. 3. The wireless communication system according to claim 1, wherein each of the slave stations that has received the notification transmits a “notification request packet” to the master station at a time designated by a start notification packet. 4. When a radio station operating in a relationship between a master station and a slave station for centralized control access on a certain channel ends centralized control access and switches to autonomous decentralized access, the master station establishes centralized control access. Transmitting an “end notification packet” indicating the end, the end notification packet indicating the end time of the centralized control access and the time until the next start notification packet is transmitted,
The slave station that has received the end notification packet includes information as to whether or not the end notification packet should be relayed to another slave station, and the slave station that has received the end notification packet determines whether the end station has received the end notification packet. At the time, the "end notification packet"
4. The wireless communication system according to claim 3, wherein the access point is transmitted to the master station to switch from centralized control access to autonomous decentralized access. 5. Each radio station performs carrier sense for a certain time for each channel, and when receiving a start notification packet from a master station, operates as a slave station subordinate to the master station in the channel, When a communication request packet from a slave station is received without receiving a start notification packet from the slave station, it operates as a transmission prohibition station that prohibits transmission while centralized control access is being performed by the master station on the channel. Thereafter, when an end notification packet is received from the master station or the slave station, transmission is performed by autonomous decentralized access until the time of the next start notification packet described in the end notification packet, and the start notification packet from the master station is transmitted. 2. The wireless communication system according to claim 1, wherein the wireless communication system operates as a master station for centralized control access on the channel when the communication request packet is not received and the communication request packet is not received. Stem. 6. When the first wireless station does not receive a start notification packet from the master station and does not receive the communication request packet, the second wireless station connected to the wireless station via another channel Selecting a radio station, wherein the first radio station operates as a master station on the channel and the second radio station operates as a slave station subordinate to the master station, or the second radio station operates as a master station. The wireless communication system according to claim 5, wherein the first wireless station operates as a station, and the first wireless station operates as a slave station subordinate to the master station. 7. A wireless station device in a wireless network constituted by a plurality of wireless stations, wherein each wireless station device has at least one channel for wireless communication, and each wireless station device has a transmission right in centralized control access. A wireless station device operable as a master station having jurisdiction over the mobile station, a slave station managed by the master station, or a transmission prohibition station, and further operable with autonomous distributed access. 8. A radio station, comprising: a plurality of radio stations, each radio station having at least one radio channel for packet radio communication, wherein each radio station communicates directly with another radio station or at least one radio channel; In a wireless communication method capable of communicating via a station, each wireless station communicates with a nearby wireless station for each wireless channel by centralized control access or autonomous decentralized access. Each radio station adaptively, for each radio channel, operates as a master station that controls a transmission right and transmits a signal under the control of its own station, or a slave station that transmits a signal under the control of the master station, A wireless communication method, wherein the centralized control access and the autonomous distributed access are performed in a time-divided manner for each wireless station and for each wireless channel. 9. A wireless station A ₁ to another wireless station A _n (n
, A ₂ , A ₃ ,... A _k , A _{k + 1} ,
.. A _n-1 (k is an integer of 2 or more and n-1 or less) when relaying and transmitting a signal, the radio station A _k is a master station and a slave station between A _k and A _{k + 1.} 9. The wireless communication according to claim 8, wherein the signal is transmitted via a wireless channel having a relationship of (1) or a wireless channel having a relationship between slave stations controlled by a master station common to A _k and A _{k + 1.} Method. 10. When a wireless station operates as a master station for centralized control access on a certain channel, the master station transmits a “start notification packet” indicating the start of centralized control access, and the start notification packet is transmitted to the master station. And the addresses of all slave stations belonging to the master station, and the time required for each slave station to transmit a “communication request packet” to the master station in response to the start notification packet. 10. The wireless communication method according to claim 8, wherein each of the slave stations that has received the notification transmits a “notification request packet” to the master station at a time designated by a start notification packet. 11. When a radio station operating in a relationship between a parent station and a child station for centralized control access on a certain channel ends the centralized control access and switches to autonomous decentralized access, the parent station performs the centralized control access. An “end notification packet” indicating the end is transmitted. The end notification packet includes the end time of the centralized control access, the time until the next start notification packet is transmitted, and the slave station that has received the end notification packet indicates the end. The slave station receiving the end notification packet includes information on whether or not the notification packet should be relayed to another slave station, and the slave station that has received the end notification packet sends the “end notification packet” to the master station at the end time notified by the end notification packet. The wireless communication method according to claim 10, wherein transmission is performed to switch from centralized control access to autonomous distributed access. 12. Each radio station performs carrier sense for a certain period of time for each channel, and when receiving a start notification packet from a master station, operates as a slave station subordinate to the master station in the channel, When a communication request packet from a slave station is received without receiving a start notification packet from the slave station, it operates as a transmission prohibition station that prohibits transmission while centralized control access is being performed by the master station on the channel. Thereafter, when an end notification packet is received from the master station or the slave station, transmission is performed by autonomous decentralized access until the time of the next start notification packet described in the end notification packet, and the start notification packet from the master station is transmitted. 9. The wireless communication according to claim 8, wherein when the communication request packet is not received and the communication request packet is not received, the wireless communication device operates as a master station of centralized control access on the channel. Method. 13. When the first wireless station does not receive the start notification packet from the master station and does not receive the communication request packet, the second wireless station connected to the wireless station through another channel Selecting a radio station, wherein the first radio station operates as a master station on the channel and the second radio station operates as a slave station subordinate to the master station, or the second radio station operates as a master station. The wireless communication method according to claim 12, wherein the first wireless station operates as a station and the first wireless station operates as a slave station subordinate to the master station.