JP2003116163A - Slave wireless station and master wireless station - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wireless packet communication system capable of simply setting a channel even in the case of presence of a plurality of installed base stations and connection of a mobile station to other base station. SOLUTION: The wireless packet communication system of this invention comprises base stations (mobile stations) 1a, 1b connected to a wired sub network 3a; mobile stations (slave stations) 2a, 2b for making wireless communication with the base station 1a; and mobile stations (slave stations) 2c, 2d for making wireless communication with the base station 1b. The base station 1a uses a channel Ch1 to make wireless communication with the mobile stations 2a, 2b belonging to the base station 1a and the mobile stations 2a, 2b use the channel Ch1 for their inter-communication. Similarly, the base station 1b uses a channel Ch2 to make wireless communication with the mobile stations 2c, 2d and the mobile stations 2c, 2d use the channel Ch2 for their inter-communication. The mobile stations 2a, 2b, the mobile stations 2c, 2d and the base stations 1a, 1b can respectively change the channels Ch1, Ch2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a wireless packet communication system for wirelessly communicating with a plurality of child wireless stations according to a channel setting selected by a parent wireless station,
More specifically, the present invention relates to a child wireless station and a parent wireless station of a wireless packet communication system in which a plurality of parent wireless stations and a plurality of child wireless stations respectively send and receive control packets to and from other stations to change and set a channel.

[0002]

2. Description of the Related Art Conventionally, as a wireless packet communication system of this type, for example, a document (DraftStandard) has been used.
IEEE802.11, P802.11D2.0, W
airless LAN Medium Access C
ontrol and Physical Layer S
those listed in "Specifications".

In this wireless packet communication system, one wireless link is shared by one base station and a plurality of mobile stations connected to a wired network, and the propagation environment and communication traffic of each base station are changed. The channels are fixedly allocated based on the prediction. In the mobile station, the user manually sets the channel used by the wireless link to which the mobile station belongs.

[0004]

In the case of the above-mentioned wireless packet communication system, if a plurality of base stations are installed, if the propagation environment or communication traffic changes during operation, the layout of channels to be allocated to the base stations is redesigned. In addition to this, when the mobile station moves and connects to another base station, the user needs to check the channel used by the destination base station and manually reset it, so for the user There is a problem that inconvenience in use is accompanied when the use condition changes.

The present invention has been made to solve such a problem, and its technical problem is to easily set a channel when installing a plurality of base stations or connecting a mobile station to another base station. It is intended to provide a wireless packet communication system capable of setting.

[0006]

According to the present invention, a plurality of parent radio stations managing a plurality of radio sub-networks respectively set one channel selected from a plurality of radio frequency channels, In a wireless packet communication system that wirelessly communicates with a plurality of child wireless stations connected to a wireless subnetwork, the plurality of parent wireless stations and the plurality of child wireless stations each send and receive control packets to and from other stations. By doing so, it is possible to obtain a wireless packet communication system that automatically sets the channel based on the result of detecting the movement of the own station and the interference between a plurality of wireless sub-networks.

Further, according to the present invention, in the above-mentioned wireless packet communication system, each of the plurality of parent wireless stations and the plurality of child wireless stations receives a channel switching request packet as a control packet from another station. A wireless packet communication system that reselects channels is obtained.

Further, according to the present invention, in the wireless packet communication system, the plurality of parent wireless stations each transmit a channel use notification packet as a control packet at regular time intervals, and the plurality of child wireless stations A wireless packet communication system that reselects a channel when a channel use notification packet from a specific one of a plurality of parent wireless stations to which the local station is connected has not been received for a certain period of time.

In addition, according to the present invention, in the above-mentioned wireless packet communication system, the plurality of parent wireless stations are each one of the plurality of wireless sub-networks which is associated with a particular station from another station associated with another station. A wireless packet communication system that reselects a channel when a channel use notification packet is received is obtained.

In these wireless packet communication systems, a plurality of parent wireless stations are connected to one of a plurality of wireless sub-networks managed by the local station when reselecting a channel and switching the channel. It is preferable to notify the corresponding newly selected channel of the child wireless stations of the newly selected channel.

Further, in these wireless packet communication systems, each of the plurality of child wireless stations transmits a channel use notification packet from a parent wireless station of another wireless sub-network that is not connected to a particular one of the plurality of parent wireless stations. It is preferable to check the connection with the parent wireless station to which the local station is connected when receiving, and reselect the channel when the connection with the parent wireless station cannot be confirmed. Furthermore, in this wireless packet communication system, each of the plurality of child wireless stations uses a channel from another station that is connected to a parent wireless station of another wireless sub-network that is not connected to a particular one of the plurality of parent wireless stations. It is preferable to confirm the connection with the parent wireless station to which the local station is connected when the notification packet is received, and reselect the channel when the connection with the parent wireless station cannot be confirmed.

On the other hand, in any one of these wireless packet communication systems, the plurality of child wireless stations are each connected to a channel from a parent wireless station of another wireless sub-network which is not connected to a particular one of the plurality of parent wireless stations. When it receives a usage notification packet, it confirms the connection with the parent wireless station to which it is connected, and when the connection with the parent wireless station is confirmed, the other wireless sub-stations of the plurality of parent wireless stations A channel switching request packet is transmitted to a network-related one, and a plurality of child wireless stations are transmitted from parent wireless stations of other wireless sub-networks that are not connected to a particular one of the plurality of parent wireless stations. When the channel use notification packet is received, the connection with the parent wireless station to which the local station is connected is confirmed, and when the connection with the parent wireless station is confirmed, the plurality of child wireless stations Sending a channel switch request packet to those of the parent radio station other wireless subnetwork out is preferred.

On the other hand, in any one of these wireless packet communication systems, the plurality of child wireless stations are connected to the parent wireless stations of other wireless sub-networks which are not connected to the specific one of the plurality of parent wireless stations. When receiving a channel switching request packet from another station, it is preferable to transmit the channel switching request packet to the parent wireless station to which the local station is connected.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The wireless packet communication system of the present invention will be described below in detail with reference to the accompanying drawings.

First, the basic configuration of the wireless packet communication system of the present invention will be briefly described. In this wireless packet communication system, a plurality of parent wireless stations managing each of a plurality of wireless sub-networks set one channel selected from a plurality of wireless frequency channels and are connected to the corresponding wireless sub-network. Wireless communication with a plurality of child wireless stations, and the plurality of parent wireless stations and the plurality of child wireless stations automatically move their own stations by transmitting and receiving control packets to and from other stations. The channel change setting is performed based on the result of detection of interference between a plurality of wireless sub-networks.

Here, each of the plurality of parent wireless stations and the plurality of child wireless stations can reselect a channel when its own station receives a channel switching request packet as a control packet from another station. . In addition, each of the plurality of parent wireless stations transmits a channel use notification packet as a control packet at regular time intervals, and each of the plurality of child wireless stations specifies a particular one of the plurality of parent wireless stations to which the own wireless station is connected. The channel can be reselected when the channel use notification packet from the source has not been received for a certain period of time. Further, each of the plurality of parent wireless stations corresponds to one of the plurality of child wireless stations connected to the one of the plurality of wireless sub-networks managed by itself when reselecting the channel and switching the channel. It is possible to notify one of the newly selected channel.

In such a wireless packet communication system,
Each of the plurality of child wireless stations is a parent to which the own station is connected when it receives a channel use notification packet from a parent wireless station of another wireless subnetwork that is not connected to a particular one of the plurality of parent wireless stations. Check the connection with the wireless station,
If the connection with the parent wireless station cannot be confirmed, the channel may be selected again, and the plurality of child wireless stations may be connected to other wireless sub-networks that are not connected to a particular one of the plurality of parent wireless stations. When a channel use notification packet is received from another station connected to the parent wireless station, the connection with the parent wireless station to which the local station is connected is confirmed, and if the connection with the parent wireless station cannot be confirmed, the channel is It is preferable to reselect.

In any one of these wireless packet communication systems, the plurality of child wireless stations are each connected to a channel from a parent wireless station of another wireless sub-network which is not connected to a particular one of the plurality of parent wireless stations. When it receives a usage notification packet, it confirms the connection with the parent wireless station to which it is connected, and when the connection with the parent wireless station is confirmed, the other wireless sub A channel switching request packet is transmitted to a network-related one, and a plurality of child wireless stations are transmitted from parent wireless stations of other wireless sub-networks that are not connected to a particular one of the plurality of parent wireless stations. When the channel use notification packet is received, the connection with the parent wireless station to which the local station is connected is confirmed, and when the connection with the parent wireless station is confirmed, multiple child wireless stations Against those of the parent radio station other wireless subnetwork out may be to transmit a channel switching request packet.

Further, in any one of these wireless packet communication systems, the plurality of child wireless stations are connected to the parent wireless stations of other wireless sub-networks which are not connected to a particular one of the plurality of parent wireless stations. When a channel switching request packet is received from another station, the channel switching request packet may be transmitted to the parent wireless station to which the local station is connected.

Therefore, some embodiments will be specifically described below.

(Embodiment 1) FIG. 1 is a block diagram showing a basic configuration of a wireless packet communication system according to Embodiment 1 of the present invention.

This wireless packet communication system includes a base station (parent wireless station) 1 connected to a wired subnetwork 3a.
a, 1b, mobile stations (child radio stations) 2a, 2b that perform radio communication between the base station 1a, and mobile stations (child radio stations) 2c, 2d that perform radio communication between the base station 1b. Composed of.

The base station 1a performs radio communication with the mobile stations 2a and 2b belonging to the base station 1a by using the channel Ch1.
The channel Ch is also used when a and 2b wirelessly communicate with each other.
1 is used. Similarly, the base station 1b performs wireless communication with the mobile stations 2c and 2d using the channel Ch2, and the mobile stations 2c and 2d
The channel Ch2 is also used when the 2d wirelessly communicate with each other. The channels Ch1 and Ch2 of the mobile stations 2a and 2b and the mobile stations 2c and 2d and the base stations 1a and 1b can be changed and set, respectively. However, here, the base stations 1a and 1b and the mobile station 2
It is assumed that a to 2d all have unique addresses,
In such a case, the channels Ch1 and Ch2 may not be divided and used, but the same channel may be used.

FIG. 2 exemplifies a control packet transmitted by a wireless station of this wireless packet communication system. This control packet includes a destination address DA, a source address SA, a control command type CT, and a host type H.
T and the master station address PA.

Among these, the destination address DA includes the address of the partner wireless station or the broadcast address that all wireless stations receive. The source address SA includes the address of the own station, and the control command type C
T includes the type of control packet. Further, the control command type CT includes a response request, a response, a channel use notification, a channel switching request, and the like. The host type HT includes the type of the transmission source wireless station, which is the master station or the slave station. The master station address PA includes the address of the master station that manages the wired subnetwork 3a connected when the own station is a slave station. It should be noted that such a control packet can be transmitted alone, but can also be a part of another data packet or the like.

FIG. 3 is a flow chart showing the procedure of communication control in the mobile stations 2a and 2b and the mobile stations 2c and 2d in this radio packet communication system.

Here, the control during communication in the mobile stations 2a and 2b and the mobile stations 2c and 2d when the base stations 1a and 1b are transmitting channel use notification packets at a constant cycle will be described first. 2a, 2b and mobile station 2
It is assumed that c and 2d hold the addresses of the base stations 1a and 1b of the currently connected wireless sub-network as CP control.

The mobile stations 2a, 2b and the mobile stations 2c, 2d start a communication and start a timer (step S1) to monitor the reception of control packets and determine whether or not control packets are received (step S2). As a result, if no control packet is received, it is determined whether or not a time-out has occurred (step S5). If a time-out has occurred, channel selection (step S6) is performed, and then the process returns before the timer start (step S1). stand by. This process may be repeated a predetermined number of times.

When the control packet is received in the judgment as to whether or not the control packet is received (step S2), HT =
It is determined whether or not it is PH (step S3), and HT = P
If it is H, it is determined whether SA = CP so that the received packet is regarded as a packet transmitted from the base stations 1a and 1b and the source address SA of the received packet is read out (step S4). As a result, if SA = CP, the received packet is the mobile station 2a, 2b or the mobile station 2c, 2
Since it cannot be regarded as the packet transmitted from d, it returns and waits before the timer start (step S1), but if SA = CP, the received packet is the mobile station 2a,
Since it can be regarded as a packet transmitted from the mobile station 2b or the mobile stations 2c and 2d, the master station address PA is read and it is determined whether or not PA = CP by comparing with the CP of the local station (step S7).
To do. As a result, if PA = CP, the process returns and waits before the timer start (step S1).

Next, it is judged whether or not SA = CP (step S4), and when SA = CP is not satisfied, that is, the received control packet of the base station 1a or the base station 1b to which the own station is connected. Regarding processing when the control packet is from a packet other than the corresponding one, the mobile stations 2a and 2b and the mobile station 2
c and 2d confirm the connection with the master station registered by the own station (step S8), and the connection with the master station registered by the own station is O.
It is determined whether it is K (step S9). As a result, if the connection is confirmed to be OK, the channel switching request packet is transmitted (step S11) to the base station 1a or base station 1b which has transmitted the control packet, and before the timer start (step S1). Return to and wait, but if the connection is not OK, select the channel (step S
10) and then timer start (step S1)
Return before and wait.

Further, when PA = CP is judged (step S7), if PA = CP is not satisfied, that is, the received control packet corresponds to the base station 1a or the base station 1b to which the own control station is connected. Regarding processing in the case of packets from mobile stations 2a, 2b and mobile stations 2c, 2d connected to other than those
2d determines whether or not the received packet is a channel switching request packet (step S12), and if it is a channel switching request packet, transmits the channel switching request packet to the base station 1a or base station 1b to which the local station is connected. After (step S17), the process returns and waits before the timer start (step S1), but if the packet is not a channel switching request packet, the connection with the master station registered by the own station is confirmed (step S13). After that, it is determined whether or not the connection with the master station registered by the own station is OK (step S
14) Do. As a result, if the connection is confirmed as OK, a channel switching request packet is transmitted to the mobile stations 2a and 2b and mobile stations 2c and 2d which have transmitted the control packet (step S16), and then a timer is started (step S16). It returns and waits before S1), but if the connection is not OK, it returns and waits before the timer start (step S1) after channel selection (step S15).

FIG. 4 is a flowchart showing a procedure of communication control processing in the base station 1a and the base station 1b in this wireless packet communication system.

The base station 1a and the base station 1b judge the reception of the control packet based on whether or not the control packet is received (step S1). If the control packet is not received, the base station 1a and the base station 1b return and stand by before this processing. If so, in order to read the host type HT of the received packet, it is determined whether or not HT = PH (step S2). As a result, HT = PH
If the received packet is a packet from other than the corresponding one of the base station 1a and the base station 1b (other base station), it is determined whether the control packet is received after the channel selection (step S4) is performed. Before returning to the standby state (step S1), but if HT = PH and the received packet is not a packet from another base station, it is determined whether or not there is a channel switching request packet (step S1).
3) Do. As a result, if there is no channel switching request packet, the process returns and waits before determining whether or not the control packet is received (step S1), but if there is a channel switching request packet, channel selection (step S4).
After performing the above step, the process returns and waits before determining whether the control packet is received (step S1).

FIG. 5 shows that the mobile stations 2a and 2b and the mobile stations 2c and 2d in this radio packet communication system are the base stations 1.
It is the flowchart which showed the processing procedure when confirming the connection with a and the base station 1b. However, it is assumed here that the base station 1a or the base station 1b transmits a response packet when it receives a response request packet from the mobile station 2a, 2b or the mobile station 2c, 2d connected to itself.

The mobile stations 2a, 2b and the mobile stations 2c, 2d transmit a response request packet to the base station 1a or the base station 1b to which they are connected at the time of confirming the connection (step S1) and then start the timer ( After performing step S2), it is determined whether a response packet is received (step S3).
As a result, if no response packet is received, it is determined whether or not a timeout has occurred (step S4), and if it is not a timeout, then it is determined whether or not a response packet is received (step S3).
Before returning, the process waits until the time-out for the reception of the response packet, but if the time-out occurs, it is determined that the connection confirmation is impossible (step S5), and the process is terminated. Further, it is determined whether or not the response packet is received (step S3), and if the response packet is received, it is determined that the connection is confirmed (step S6), and then the process is ended.

FIG. 6 shows the mobile stations 2a and 2b and the mobile station 2 which are connected to the base station 1a and the base station 1b in the wireless packet communication system when they select a new channel.
It is the flowchart which showed the processing procedure when notifying the newly selected channel with respect to c and 2d.

The base station 1a and the base station 1b first select a new channel (step S1) and then assign the number of the newly selected channel using the channel used before the selection to the mobile stations 2a and 2b. The data is transmitted to the mobile stations 2c and 2d (step S2). Next, communication is started using the newly selected channel (step S3). Mobile stations 2a, 2b
When receiving the notification from the base station 1a or the base station 1b, the mobile stations 2c and 2d switch to the new channel notified by the base station 1a or the base station 1b to perform communication.

(Embodiment 2) FIG. 7 is a block diagram showing the basic configuration of a radio packet communication system according to Embodiment 2 of the present invention.

This wireless packet communication system includes a mobile station 2 that does not include a base station connected to a wired subnetwork.
The wireless sub-network is composed of only e, 2f, 2g, 2h, 2i and 2j. In such a configuration, an arbitrary mobile station serves as a master station to manage the wireless sub-network, and mobile stations other than the master station communicate using the channel selected by the master station.

When configuring an independent network composed of only such mobile stations, the control performed by the base station 1a and the base station 1b in the system of the first embodiment is performed by the mobile station which is the master station. When the mobile station serving as the master station moves between the wireless sub-networks, another mobile station becomes a new master station in the original wireless sub-network. This allows
Even in a wireless subnetwork where there is no base station,
Interference between wireless sub-networks can be avoided,
The mobile station can automatically select the channel used at the destination.

(Third Embodiment) FIG. 8 is a block diagram showing a basic configuration of a radio packet communication system according to a third embodiment of the present invention.

This wireless packet communication system is a form in which the system of the first embodiment and the system of the second embodiment are mixed, and the mobile station 2k that performs wireless communication with the base station 1c connected to the wired network 3b. , 2l, and a mobile station 2o, mobile stations 2p, 2q that perform wireless communication independently of each other,
It is composed of mobile stations 2m and 2n that perform wireless communication with the base station 1d connected to the wired network 3b, and mobile stations 2r, 2s and 2t that independently perform wireless communication with each other.

As in this configuration, the base station 1c and the base station 1
In a situation where the wireless sub-network in which d exists and the wireless sub-network in which the base station 1c and the base station 1d do not exist are mixed, the processing performed by the base station 1a and the base station 1b in the first embodiment is performed by the base station 1c. In the wireless sub-network in which the base station 1d and the base station 1d exist, these base stations 1c and 1d
In the wireless sub-network in which the base station 1c or the base station 1d does not exist, the mobile station which is the master station performs. As a result, even in a situation in which the wireless sub-network in which the base station 1c or the base station 1d exists and the wireless sub-network in which the base station 1c or the base station 1d does not exist are mixed, the system of the first embodiment or the system of the second embodiment. Similarly, interference between wireless sub-networks can be avoided, and the mobile station can automatically select the channel used at the movement destination.

[0044]

As described above, according to the wireless packet communication system of the present invention, each wireless station transmits / receives a control packet so that when the wireless station moves between wireless sub-networks, It becomes possible to detect movement and dynamically select the channel used in the wireless subnetwork of the movement destination, and also to be able to dynamically switch channels while avoiding interference between wireless subnetworks. Become. This eliminates the need to reconfigure the channel when the wireless station moves, and eliminates the need to redo the channel layout design when the wireless subnetwork layout, propagation environment, and communication traffic changes. It is possible to automatically switch the channels used in each wireless sub-network according to the propagation environment and communication traffic.

[Brief description of drawings]

FIG. 1 is a block diagram showing a basic configuration of a wireless packet communication system according to a first embodiment of the present invention.

FIG. 2 illustrates a control packet transmitted by a wireless station of the wireless packet communication system shown in FIG.

FIG. 3 is a flowchart showing a procedure of communication control in a mobile station in the wireless packet communication system shown in FIG.

FIG. 4 is a flowchart showing a processing procedure of communication control in a base station in the wireless packet communication system shown in FIG.

5 is a flowchart showing a processing procedure when a mobile station confirms a connection with a base station in the wireless packet communication system shown in FIG.

6 is a flowchart showing a processing procedure when a base station in the wireless packet communication system shown in FIG. 1 notifies a mobile station connected to itself of a newly selected channel when the base station selects the new channel. Is.

FIG. 7 is a block diagram showing a basic configuration of a wireless packet communication system according to a second embodiment of the present invention.

FIG. 8 is a block diagram showing a basic configuration of a wireless packet communication system according to a third embodiment of the present invention.

[Explanation of symbols]

1a, 1b, 1c, 1d base station 2a to 2d, 2e to 2j, 2k to 2t mobile stations 3a, 3b Wired network

Continued front page    F-term (reference) 5K033 AA09 CC01 DA02 DA17 DB16                       EA03                 5K067 AA11 AA21 BB02 BB21 DD19                       DD34 DD51 EE02 EE10 EE41                       EE63 FF03 GG01 GG11 JJ11                       JJ31 JJ76

Claims (14)

[Claims] 1. A plurality of parent wireless stations managing respective ones of a plurality of wireless sub-networks, each set with one channel selected from a plurality of wireless frequency channels and connected to the corresponding wireless sub-network. In a child wireless station in a wireless packet communication system that wirelessly communicates with another child wireless station, if a control packet from the parent wireless station to which the own station is connected has not been received for a certain period of time, channel selection processing is performed and other stations Control packet received from the control packet, the type of the control packet included in the control packet, the address of the wireless station that transmitted the control packet, the type of the wireless station that transmitted the control packet, or the control packet transmitted. Channel selection processing based on the connected master station address of the selected wireless station or a combination of these. Child radio station that the butterflies. 2. When the received control packet is transmitted from a parent wireless station of a wireless sub-network to which the own station is not connected, the connection confirmation with the parent wireless station to which the own station is connected is performed. The child radio station according to claim 1, wherein the channel selection process is performed when the connection with the parent radio station cannot be confirmed. 3. When the received control packet is transmitted from a child wireless station of a wireless sub-network that does not have a connection relationship with itself, the connection confirmation with the parent wireless station to which the own station is connected is performed. The child radio station according to claim 1, wherein the channel selection process is performed when the connection with the parent radio station cannot be confirmed. 4. When the received control packet is transmitted from a parent wireless station of a wireless sub-network to which the own station is not connected, the connection confirmation with the parent wireless station to which the own station is connected is performed. , If the connection with the parent wireless station is confirmed,
The slave wireless station according to claim 1, wherein the local station transmits a channel switching request packet to a wireless station of a wireless sub-network having no connection relationship. 5. When the received control packet is transmitted from a child wireless station of a wireless subnetwork to which the own station is not connected, the connection check with the parent wireless station to which the own station is connected is performed. , If the connection with the parent wireless station is confirmed,
The slave wireless station according to claim 1, wherein the local station transmits a channel switching request packet to a wireless station of a wireless sub-network having no connection relationship. 6. If the received control packet is a channel switching request packet transmitted from a child radio station of a radio sub-network to which the self station is not connected, the master radio station to which the self station is connected is sent. The slave radio station according to claim 1, which transmits the channel switching request packet. 7. A plurality of parent wireless stations managing respective ones of a plurality of wireless sub-networks, each set with one channel selected from a plurality of wireless frequency channels and connected to the corresponding wireless sub-network. In the parent wireless station in the wireless packet communication system that wirelessly communicates with the child wireless station, the type of the control packet included in the control packet or the wireless that transmitted the control packet in the parent wireless station A parent wireless station which performs channel selection processing based on the type of station or a combination thereof. 8. The parent wireless station according to claim 7, wherein when the received control packet is a channel switching request packet, channel selection processing is performed. 9. The channel selection process is performed when the received control packet is transmitted from a child radio station of a radio sub-network not managed by the own station. Parent radio station. 10. A plurality of parent wireless stations managing respective ones of a plurality of wireless sub-networks, each set with one channel selected from a plurality of wireless frequency channels and connected to a corresponding wireless sub-network. In the parent wireless station in the wireless packet communication system that wirelessly communicates with the child wireless station, when the channel selection processing is performed and the channel is switched, the wireless wireless communication system is connected to one of the plurality of wireless sub-networks managed by the local station. A parent wireless station, which notifies a newly selected channel to a corresponding one of a plurality of child wireless stations. 11. A plurality of parent wireless stations managing each of a plurality of wireless sub-networks, each set with one channel selected from a plurality of wireless frequency channels, and connected to the corresponding wireless sub-network. In a child wireless station in a wireless packet communication system that wirelessly communicates with another child wireless station, the one of the plurality of wireless sub-networks is managed by the parent wireless station when the parent wireless station performs channel selection processing and switches the channel. The newly selected channel for the corresponding one of the plurality of connected child radio stations is
A child radio station which is notified from the parent station and switches to the channel. 12. A plurality of parent wireless stations managing respective ones of a plurality of wireless sub-networks, each set with one channel selected from a plurality of wireless frequency channels and connected to a corresponding wireless sub-network. In the wireless packet communication system that wirelessly communicates with the child wireless station, it is determined whether or not to perform the channel selection process depending on whether or not a control packet is received from another station. Child radio station. 13. The slave radio station according to claim 12, wherein channel selection processing is performed when a control packet from the parent radio station to which the local station is connected has not been received for a certain period of time. 14. When a control packet from another station is received, the type of the control packet included in the control packet, the address of the wireless station that has transmitted the control packet, and the wireless station that has transmitted the control packet. 13. The slave radio station according to claim 12, wherein the channel selection process is performed based on the type, the master station address to which the radio station transmitting the control packet is connected, or a combination thereof.