JP4825915B2 - Channel change method and subnetwork configuration method in wireless network - Google Patents

Abstract

A method of performing handover in a wireless network and a device thereof are provided to supply communication without disconnection without respect to a situation of a specific device. The first device is selected as a new regulator. A handover request message is transmitted to the first device(S410). A response message about the handover request message is received from the device(S440). A beacon is broadcast(S480). The beacon includes ID of the first device and the number of beacons that the regulator transmits before handover. The first device broadcasts the beacon as the new regulator after the regulator broadcasts the last beacon(S570).

Description

  The present invention relates to a wireless network, and more particularly to a channel change method and a sub-network configuration method in a wireless network.

  In recent years, Bluetooth, wireless private networks that can form a wireless network between a relatively small number of digital devices in a limited space such as a home or small work place and exchange audio or video data between these devices. Network (WPAN: Wireless Personal Area Network) technology has been developed. WPAN can be used to exchange information between a relatively small number of digital devices at relatively close distances, allowing low power and low cost communication between digital devices. IEEE 802.15.3 approved on June 12, 2003 (Wireless Medium Access Control (MAC) and Physical Layer (PHY) Specialties for High Rate Wireless Network) (MAC) and physical layer (PHY) specifications are defined.

  FIG. 1 is a diagram illustrating a configuration example of a WPAN. As shown in FIG. 1, WPAN is a network configured between personal devices (devices) in a limited space such as a home. The network is configured by direct communication between devices, and between applications (applications). Make it possible to exchange information without interruption. Referring to FIG. 1, the WPAN includes two or more user devices 11 to 15, one of which operates as a coordinator 11. The coordinator 11 provides basic timing of WPAN, and plays a role of controlling QoS (Quality of Service) requirements. Devices that can be used as devices include computers, PDAs, notebooks, digital TVs, camcorders, digital cameras, printers, microphones, speakers, headsets, barcode readers, displays, mobile phones, and any other digital Equipment is also available.

  The WPAN is not designed and built in advance, but is an ad hoc network (hereinafter referred to as a “piconet”) that is formed when necessary without the assistance of a central infrastructure. The process of forming one piconet will be specifically described as follows. A piconet begins when any device that can operate as a coordinator performs the function of a coordinator. All devices start a new piconet or scan before joining an existing piconet. Scanning refers to a process in which a device collects and stores channel information and checks whether an existing piconet is present. A device instructed to start a piconet from an upper layer forms a new piconet without joining a piconet already formed on any channel. The device starts a piconet by selecting a channel with less interference based on data acquired in the scanning process and broadcasting a beacon through the selected channel. Here, the beacon is control information that the coordinator broadcasts in order to control and manage the piconet, such as timing allocation information and information about other devices in the piconet.

  FIG. 2 is a diagram illustrating an example of a superframe used in a piconet. Timing control in a piconet is basically performed on the basis of a superframe. Referring to FIG. 2, each super frame begins with a beacon transmitted from the coordinator. A contention period (CAP) is used by a device to transfer commands and asynchronous data on a contention-based basis. The channel time allocation section may include a management channel time block (MCTB) and a channel time block (CTB). The MCTB is a section in which control information can be transferred between the coordinator and the device or between the devices and the device, and the CTB is the asynchronous or isochronous data between the device and the coordinator or between other devices. This is a section that can be transferred. In each superframe, the number, length, and position of CAP, MCTB, and CTB are determined by the coordinator and transferred to other devices in the piconet through a beacon.

  If any device in the piconet needs to transfer data to the coordinator or other device, this device requests the channel time for data transfer from the coordinator, and the coordinator uses the available channel resources. Allocate channel time to devices within range. If there is a race interval in the superframe and the coordinator grants data transfer in this race zone, the device can transfer a small amount of data through the race zone without receiving channel time from the coordinator. .

  When the number of devices in the piconet is small, there is no special problem in channel time allocation because each device has enough channel resources to transfer data, but there are many devices because of the large number of devices. If a specific device continues to occupy a channel and transfers a large amount of data such as a moving image even if the number of devices is insufficient, the other device has data to transfer. However, channel resources cannot be received, and a situation where communication is impossible can occur. Moreover, even if channel resources can be received, a situation may occur in which only channel resources that are smaller than the capacity of stored data can be received.

  The present invention is to solve the above-described problems of the prior art, and an object of the present invention is to provide a communication method that can efficiently use channel resources in a wireless network.

  Another object of the present invention is to provide a method for allowing a device belonging to an existing wireless network to easily form another wireless network using another channel.

  A channel change method in a wireless network according to an aspect of the present invention is a channel change method of a first device in a wireless network comprising a first coordinator and at least one device, wherein the channel change method is in use in the wireless network. Searching for availability of other channels other than the first channel; changing the channel to a second channel of at least one of the available channels as a result of the search; and second through the second channel. Transferring data to a device and receiving data from the second device.

  A channel change method in a wireless network according to another aspect of the present invention is a channel change method in a wireless network including a coordinator, and the channel change method in response to a channel resource allocation request in a channel being used in the wireless network. Receiving a rejection response from the coordinator, searching for availability of a channel other than the current channel, and requesting the coordinator to change the channel to a specific channel among at least one usable channel. And a step of changing the channel to the specific channel when the coordinator permits the channel change.

  According to still another aspect of the present invention, a channel change method in a wireless network is a channel change method of a first device in a first wireless network that performs communication through a first channel and a second channel, and for channel change. Searching for a channel other than the first channel and the second channel, changing the channel to the third channel and the fourth channel selected according to the search result, and broadcasting a beacon through the fourth channel And a stage including

  According to still another aspect of the present invention, a method for configuring a sub-network in a wireless network searches for availability of a channel other than the first channel being used in the first wireless network including the coordinator, As a result of the search, the configuration includes a step of changing the channel to the second channel of at least one usable channel and a step of configuring a sub-network through the second channel.

In the embodiment of the present invention, it is preferable that each device of the wireless network newly formed by the channel change grasps the state of the conventional wireless network. For this reason, each device of the new wireless network needs to return to the conventional wireless network during a certain interval on the superframe. In particular, it is preferable to receive the channel of the conventional wireless network during a beacon transfer interval or a non-reserved interval of the conventional wireless network.
For example, the present invention provides the following items.
(Item 1)
A method of changing a channel of a first device in a wireless network comprising a first coordinator and at least one device comprising:
Searching for availability of channels other than the first channel being used in the wireless network;
As a result of the search, changing the first channel to a second channel of at least one available channel;
Operating as a second coordinator on the second channel and transferring a second beacon;
Transferring data to the second device through the second channel and receiving data from the second device;
Including channel change method.
(Item 2)
2. The channel change method according to item 1, further comprising receiving a first beacon transferred from the first coordinator by returning to the first channel.
(Item 3)
Item 3. The channel change method according to Item 2, wherein the first channel is received in a predetermined time interval based on channel interval information included in the first beacon.
(Item 4)
Item 2. The channel change method according to Item 1, wherein the second beacon includes channel interval information in the second channel determined based on channel interval information included in the first beacon.
(Item 5)
Item 5. The channel change method according to Item 4, wherein data is transmitted / received through the second channel in a data transfer interval defined by channel interval information included in the second beacon.
(Item 6)
2. The channel changing method according to item 1, wherein the second beacon includes information notifying that the second channel is a temporary channel.
(Item 7)
A method for channel change of a first device in a wireless network comprising a coordinator comprising:
Receiving a rejection response from the coordinator in response to a channel resource allocation request on a channel in use in the wireless network;
Searching for availability of channels other than the current channel;
Requesting the coordinator to change the channel to a specific channel among at least one of the available channels;
If the coordinator grants a channel change, changing the channel to the specific channel;
Including channel change method.
(Item 8)
8. The channel changing method according to item 7, further comprising: generating a second wireless network through the specific channel.
(Item 9)
The second wireless network generation stage includes
Transferring a beacon through the specific channel;
Transmitting or receiving data in the data transfer section indicated by the channel section information included in the beacon;
The channel changing method according to item 8, characterized by comprising:
(Item 10)
Item 8. The channel change method according to Item 7, wherein the first device registers that the first device has changed the channel to the specific channel in the adjuster.
(Item 11)
A method of changing a channel of a first device in a first wireless network that communicates through a first channel and a second channel, comprising:
Searching for a channel other than the first channel and the second channel for channel change;
Changing the channel to the third channel and the fourth channel selected according to the search result;
Broadcasting a beacon through the fourth channel;
A channel change method in a wireless network including:
(Item 12)
12. The method of changing a channel in a wireless network according to item 11, further comprising: transferring data to the second device through the fourth channel or receiving data from the second device.
(Item 13)
Item 12. The channel change method in the wireless network according to Item 11, wherein the third channel and the fourth channel are located in the same frequency band.
(Item 14)
12. The method of changing a channel in a wireless network according to item 11, further comprising receiving a beacon transferred from the coordinator of the first wireless network by returning to the second channel.
(Item 15)
15. The channel in a wireless network according to item 14, wherein the first channel or the second channel is received in a predetermined time interval according to channel interval information included in a beacon received from the coordinator of the first wireless network. Modification method.
(Item 16)
12. The channel change method in the wireless network according to item 11, wherein the beacon transmitted through the fourth channel includes information notifying that the third channel and the fourth channel are channels temporarily used. .
(Item 17)
Search for availability of channels other than the first channel including the first low-speed physical channel and the first high-speed physical channel that are in use in the first wireless network including the coordinator and exist in the same frequency band. And the stage of
As a result of the search, changing the channel to a second channel including a second high-speed physical channel and a second low-speed physical channel existing in the same frequency band among at least one usable channel;
Configuring a sub-network through the second channel group;
A sub-network configuration method including:
(Item 18)
The subnetwork configuration stage
Item 18. The subnetwork configuration method according to Item 17, further comprising the step of transferring a beacon through the second low-speed physical channel.
(Item 19)
19. The subnetwork configuration method according to item 17 or 18, further comprising the step of returning to the second low-speed physical channel and receiving a beacon transferred from the coordinator of the first wireless network.
(Item 20)
Item 17, wherein the first high-speed physical channel or the first low-speed physical channel is received in a predetermined time interval according to channel interval information included in a beacon transmitted from the coordinator of the first wireless network. Subnetwork configuration method.
(Item 21)
Item 18. The subnetwork configuration method according to Item 17, wherein the beacon transmitted through the second low-speed physical channel includes information notifying that the subnetwork is a network configured temporarily.

  Advantageous Effects of Invention According to the present invention, channel resources can be used efficiently in a wireless network, and an effect that a device belonging to an existing wireless network can easily form another wireless network using another channel can be obtained. .

It is a figure which shows the structural example of WPAN. It is a figure which shows an example of the super-frame (superframe) used with a piconet. It is a figure which shows an example of a structure of WVAN. It is a figure for demonstrating the frequency band of the HRP channel and LRP channel which are used by WVAN. It is a figure which shows an example of the structure of the super frame used by WVAN. 5 is a flowchart illustrating a process according to a preferred embodiment of the present invention. FIG. 6 is a diagram illustrating an example of a process in which a device operates after a channel change according to an exemplary embodiment of the present invention. FIG. 6 is a diagram illustrating another example of a process in which a device operates after a channel change according to an exemplary embodiment of the present invention. 5 is a flowchart illustrating a process according to another preferred embodiment of the present invention.

  The configuration, operation, and other features of the present invention can be easily understood through embodiments of the present invention described below with reference to the accompanying drawings. The following embodiments are examples in which the technical features of the present invention are applied to a WVAN (Wireless Video Area Network) which is a kind of wireless private network (WPAN).

  FIG. 3 is a diagram illustrating an example of the configuration of the WVAN. As shown in FIG. 1, the WVAN includes two or more user devices 31 to 35, and one of the devices operates as a coordinator 31. The coordinator 31 provides basic timing of WVAN, and plays a role of controlling QoS (Quality of Service) requirements. One of the differences between the WVAN shown in FIG. 3 and the WPAN in FIG. 1 is that it supports two types of physical layers (PHYs). That is, the WVAN in FIG. 3 supports high-rate physical layer (HRP) and low-rate physical layer (LRP) as physical layers. HRP is a physical layer that can support a data transfer rate of 1 Gb / s or more, and LRP is a physical layer that supports a data transfer rate of several Mb / s. HRP is highly directed and is used for isochronous data stream, asynchronous data, MAC command, and A / V control data transfer through unicast connection. The LRP supports a directional or omni-directional mode, and is used for beacon, asynchronous data, MAC command transfer, etc. through unicast or broadcast.

  FIG. 4 is a diagram for explaining the frequency bands of the HRP channel and the LRP channel used in the WVAN. HRP uses four channels with a 2.0 GHz bandwidth in the 57-66 GHz band, and LRP uses three channels with a 92 MHz bandwidth. As shown in FIG. 4, the HRP channel and the LRP channel share a frequency band and are used by being divided by the TDMA method.

  FIG. 5 is a diagram illustrating an example of a superframe structure used in WVAN. Referring to FIG. 5, each super frame is allocated by a coordinator, a beacon transfer area (beacon region), a reserved area (reserved region) allocated to an arbitrary device by a coordinator according to a device request. And unreserved regions that transmit and receive data between the coordinator and the device or between the devices and the device in a contention-based manner, and each region is time-divided. The The beacon includes timing allocation information in the corresponding superframe and WVAN management / control information. The reserved area is used to transfer data to other devices by the coordinator allocating channel time in response to a channel time allocation request from the device. Command words, data streams, asynchronous data, etc. can be transferred through the reserved area. The HRP channel is used when a specific device transfers data to other devices through the reserved area, and the LRP channel is used when a device receiving data transfers an acknowledgment (ACK / NACK) signal for the received data. use. The non-reserved area can be used to transfer control information, MAC command words, asynchronous data, and the like between the coordinator and the device or between the devices. In order to prevent data collision between devices in a non-reserved area, a CSMA (Carrier Sense Multiple Access) method or a slotted Aloha method can be applied. In the non-reserved area, data can be transferred only through the LRP channel. If there are many control information and command words to be transferred, it is possible to set a reserved area in the LRP channel. The length and number of reserved and non-reserved areas in each superframe can vary from one superframe to another and is controlled by the coordinator.

  FIG. 6 is a flowchart illustrating a process according to a preferred embodiment of the present invention. In the figure, it is assumed that the coordinator, the first device, the second device, and many other devices constitute one WVAN through a specific HRP channel and an LRP channel. However, for convenience of explanation, devices other than the first device and the second device are omitted in the drawings.

  Referring to FIG. 6, the coordinator broadcasts a beacon in the WVAN so that a device in the WVAN can receive the beacon [S61]. The first device and the second device acquire channel time allocation information and WVAN management or control information in the corresponding superframe through the received beacon. If there is data to be transferred to the second device or data to be received from the second device, the first device requests channel resource assignment from the coordinator [S63]. The coordinator determines whether there is a channel resource to be allocated to the first device in response to the channel resource allocation request of the first device. If there is no channel resource to be allocated to the first device [S64], the coordinator transfers a message rejecting the channel allocation request of the first device to the first device [S65].

  The first device that has received the rejection message for the channel assignment request performs a scanning operation on the coordinator to search for a usable channel among channels other than the channel being used in the current WVAN. This is reported [S66]. The first device and the second device perform scanning in order to select the most suitable channel to use from among the available channels [S67]. The scanning operation may be performed by either the first device or the second device, or may be performed by both the first device and the second device. As the scanning order, first, the channel status of the LRP channel is checked, an LRP channel having a good channel status is selected, and the channel status of the HRP channel corresponding to the selected LRP channel is determined, and the best HRP is selected. The method of selecting can be considered. Conversely, it is also possible to select an LRP channel from the selected HRP channel by first scanning the HRP channel. When the scanning operation is completed, the first device selects a channel to move through negotiation based on the scanning result [S68]. That is, the first device and the second device select the most appropriate set from among all the HRP channel and LRP channel sets. In selecting a channel, it is preferable to select a channel having the least interference with a channel used in an existing WVAN.

  The first device or the second device requests the coordinator to change the channel to the selected HRP channel and LRP channel [S69]. At this time, the first device provides the coordinator with the index of the selected HRP channel and the LRP channel and the identifier (ID) information of the device that changes the channel to the selected channel, that is, the second device. When the coordinator permits the channel change of the first device and the second device, the channel change fact is registered [S70], and a message for approving the channel change is transferred to the first device and the second device [S71]. In this case, the coordinator may transmit a message for approving the channel change to the first device that requested the channel change, and the first device may communicate the channel change approval fact to the second device. The coordinator can create and store a list of devices that change channels and inform other devices periodically or aperiodically. When the first device and the second device receive the channel change approval message from the coordinator, the channel is changed to the selected HRP channel and LRP channel [S72].

  After the channel change, the first device and the second device constitute a sub-network, and either one operates as a coordinator on the changed new channel. Various methods can be considered as a method for determining which device operates as a regulator. For example, it can be considered that a device (first device in FIG. 6) that requests a channel change from the coordinator operates as a coordinator. Alternatively, a method of determining a device that operates as a coordinator according to a predetermined priority (priority) can be considered. In other words, some devices may not be suitable for operating as a coordinator that manages and controls one WVAN. Therefore, priorities that take into account various characteristics of the device are set in advance, If each device shares priority information of all devices, it can be easily determined whether the device should operate as a regulator. Device characteristics that can be considered when determining priorities include whether video display is possible, whether the power is on continuously, proximity to other devices, output power, etc. be able to.

  FIG. 6 is an example in which the first device operates as a coordinator, and the first device transfers a beacon through the changed channel. FIG. 7 is a diagram illustrating an example of a process in which a device operates after a channel change according to an exemplary embodiment of the present invention. In FIG. 7, channel #i is a channel before channel change, and channel #j is a channel after channel change. Both channel #i and channel #j include an HRP channel and an LRP channel. It can be assumed that a new WVAN is formed on channel #j by the first device broadcasting a beacon after changing the channel to channel #j. However, the new WVAN can be said to be an auxiliary WVAN formed temporarily using another channel because a device on the existing WVAN could not secure sufficient channel resources on the existing WVAN. The first device includes the identification information informing the new WVAN that it is an auxiliary network of the existing WVAN in the beacon transmitted by the first device, so that the newly joining device selects the existing WVAN or the new WVAN. It is preferable to be able to join.

  Referring to FIG. 7, when the first device and the second device that have formed a new WVAN need to know the status of the existing WVAN, they return to the original channel (#i) periodically or aperiodically, An LRP channel or an HRP channel can be received during a certain period. For example, the first device and / or the second device grasps in advance transfer section information on a superframe from a beacon transferred by an existing WVAN adjuster (hereinafter referred to as a “first adjuster”), A beacon and / or an unreserved region transferred from the first coordinator on channel #i when necessary or periodically can be received. In this case, it is preferable that the first device and the second device receive a beacon transmitted from the first coordinator and a non-reserved area following the beacon.

  The new WVAN coordinator (first device, hereinafter referred to as the “second coordinator”) can forward the beacon in the new WVAN in synchronization with the beacon transmitted by the first coordinator. The beacon in the new WVAN may be transferred regardless of the beacon transmitted by the first coordinator. In FIG. 7, the second coordinator transfers its beacon in synchronization with the beacon transmitted by the first coordinator. Since the beacon transmitted by the first coordinator includes channel section information of the superframe of the channel used in the existing WVAN, the second coordinator has the beacon region, reserved region, and non-reserved channel of the channel #i. The area can be divided. Based on the above information, the second coordinator sets a beacon area to be assigned to channel #j, a reserved area, and a hopping area to channel #i in its own beacon. All devices that have moved to (the second device in FIG. 6) use channel #j or hop to channel #i to share the non-reserved region of channel #i, thereby Control and management information can be sent and received through When the first device and the second device finish receiving the non-reserved area, the channel is changed again according to the beacon information received through the channel #i, the channel #j is switched to the transmission / reception mode, and the beacon transferred by the second adjuster The communication scheduled by is performed. If the first coordinator confirms from the beacon transmitted by the first coordinator that there is data to be transferred to the first device or the second device through the reserved area of the channel #i, the first device or the second device may change the channel as necessary. Data can be received after switching to #i.

  When transmitting and receiving data between the first device (second coordinator) and the second device in the reserved area of channel #j, the receiving side uses the automatic retransmission method (ARQ) or the data packet transferred from the transmitting side. In some cases, an acknowledgment (ACK) or an acknowledgment (NACK) signal should be transferred by the hybrid automatic retransmission method (HARQ). At this time, the LRP region of channel #j is used. The second coordinator can perform communication while switching between the channel #i and the channel #j using the channel section information of the channel #i included in the beacon transferred by the first coordinator. In order for the second coordinator to share more non-reserved areas of channel #i, the reserved area of channel #i and the reserved area of channel #j are matched, or the reserved area of channel #j is It is preferable to make it smaller than the reserved area so that the second coordinator can receive all the non-reserved areas of channel #i.

  Referring to FIG. 6 again, when the data transfer through the channel #j is completed between the first device and the second device, the first device and the second device make a channel return request to the first adjuster [S76]. The first coordinator registers the channel return of the first device and the second device [S77], and forwards a message for approving the channel return [S78]. Upon receiving this channel return approval message, the first device and the second device return to channel #i, which is the original channel [S79].

  FIG. 8 is a diagram illustrating another example of a process in which a device operates after a channel change according to an exemplary embodiment of the present invention. In the embodiment of FIG. 6, after the first device and the second device change the channel [S72], they operate as a new WVAN unrelated to the existing WVAN. In the example of FIG. 7, the first device and the second device repeat the channel switch in order to grasp the state of the existing WVAN even after the channel is changed, and the non-reserved area of the channel #i that is the channel used by the existing WVAN In the example of FIG. 8, after the channel change, the first device and the second device independently form a new WVAN and perform communication. Accordingly, the second coordinator of the new WVAN can transfer its beacon without synchronizing with the beacon transmitted by the first coordinator of the existing WVAN. Further, since the reserved area and the non-reserved area can be separately used by using the HRP channel and the LRP channel in the new WVAN, it is possible for a new device to join the new WVAN. When communication is completed between the first device and the second device, the channel is switched to channel #i to return to the conventional WVAN, and the beacon transmitted by the first coordinator is received. When the first device and the second device make a channel return request to the first coordinator and receive an approval for the channel return request from the first coordinator, normal communication can be performed with the conventional WVAN.

  FIG. 9 is a flowchart illustrating a process according to another preferred embodiment of the present invention. Unlike the embodiment of FIG. 6, in the embodiment of FIG. 9, the first device and the second device perform the scanning process without requesting the channel resource allocation to the coordinator when the channel resource is requested [S83, S84]. ] After selecting a channel [S85], the channel is immediately changed to form an auxiliary WVAN. For example, it is necessary to continuously transfer a large-capacity data stream between the first device and the second device belonging to the existing WVAN while grasping the status of the existing WVAN. If it is necessary to quickly return to the existing WVAN, a new WVAN that assists the existing WVAN by using a channel other than the channel used in the existing WVAN by its own judgment without requesting channel resource allocation in the existing WVAN. Must be generated. The rest of the procedure is as described in FIG. 6 and FIG. 7 or FIG.

  The terms used above can be replaced with different ones. For example, the device can be a user device (or equipment), a station, etc., and the coordinator can be a coordinator (or control) device, coordinator (or control) device, coordinator (or control) station, coordinator. (Coordinator), PNC (piconet coordinator), and the like.

  In the above embodiment, the constituent elements and features of the present invention are combined in a predetermined form. Each component or feature should be considered optional unless stated otherwise. Each component or feature may be implemented in a form that is not combined with other components or features, and some components and / or features may be combined to form an embodiment of the present invention. The order of operations described in the embodiments of the present invention can be changed. Some configurations or features of one embodiment may be included in other embodiments, or may be replaced with corresponding configurations or features of other embodiments. In addition, it is obvious that claims which do not have an explicit citation relationship in the claims can be combined to constitute an embodiment, or can be included as new claims by amendment after application.

  Embodiments according to the present invention may be implemented by various means such as hardware, firmware, software, or a combination thereof. When implemented in hardware, embodiments of the present invention include one or more ASICs (application specific integrated circuits), DSPs (digital signal processors), DSPDs (digital signal processes), DSPS (digital signal processes), DSPS (digital signal processes). (Field programmable gate arrays), a processor, a controller, a microcontroller, a microprocessor, and the like.

  In the case of implementation by firmware or software, an embodiment of the present invention may be implemented in the form of a module, procedure, function, or the like that performs the functions or operations described above. The software code can be stored in a memory unit and driven by a processor. This memory unit is located inside or outside the processor and can exchange data with the processor by various known means.

  Those skilled in the art to which the present invention has been described can understand that the present invention can be implemented in other specific forms without changing the technical idea and essential features thereof. Accordingly, the embodiments described above are illustrative in all aspects and should not be construed as limiting. The scope of the present invention is defined not by the above detailed description but by the following claims, and accordingly, any changes or modifications derived from the meaning and scope of the claims and the equivalents thereof will be described. It should be construed as being included within the scope of the present invention.

Claims (10)

A method for establishing a sub-network by a device of a first wireless network, comprising:
Searching whether another channel other than the first channel including the first high speed physical channel and the first low speed physical channel is available, the first high speed physical channel and the A first low-speed physical channel is currently used in the first wireless network including a coordinator and is in a first frequency band;
Switching from the first channel to the second channel, the second channel comprising a second high speed physical channel and a second low speed physical channel, the second high speed physical channel and the A second slow physical channel is present in a second frequency band of at least one available channel based on the search results;
Establishing the subnetwork on the second channel to broadcast a beacon on the second low speed physical channel, wherein the coordinator establishes the subnetwork on the second channel. Continued broadcasting beacons on the first low-speed physical channel in the first wireless network after being
Periodically returning to the first channel for a period of time to receive a beacon transmitted from the coordinator and a non-reserved region following the beacon, wherein the device Returning to the second channel after receiving the beacon and the non-reserved region on the first channel to communicate with at least one device in the network;
Including a method. The method of claim 1, wherein a transmitted beacon broadcast by the coordinator of the subnetwork includes information indicating that the subnetwork is temporarily configured. The method of claim 1, further comprising providing an index of the second low speed physical channel and the second high speed physical channel to a coordinator of the first wireless network. The method of claim 1, further comprising providing device identification information for switching the first channel to the second channel. The method of claim 1, wherein the coordinator of the first wireless network notifies a device in the first wireless network of a list of devices that perform the channel switching. A device for use in a wireless network, the device comprising:
Searching whether another channel other than the first channel including the first high speed physical channel and the first low speed physical channel is available, the first high speed physical channel and the The first low speed physical channel is currently used in a first wireless network including a coordinator and is in a first frequency band;
Switching from the first channel to the second channel, the second channel comprising a second high speed physical channel and a second low speed physical channel, the second high speed physical channel and the A second slow physical channel is present in a second frequency band of at least one available channel based on the search results;
Broadcasting a beacon on the second low-speed physical channel in a subnetwork established on the second channel, wherein the coordinator is configured so that the subnetwork is established on the second channel. At a later time, continuing to broadcast beacons on the first low-speed physical channel in the first wireless network;
Periodically returning to the first channel for a period of time to receive a beacon transmitted from the coordinator and a non-reserved region following the beacon, wherein the device Returning to the second channel after receiving the beacon and the non-reserved region on the first channel to communicate with at least one device in the network;
Configured to do the device. The device of claim 6, wherein a transmitted beacon broadcast by the coordinator of the subnetwork includes information indicating that the subnetwork is temporarily configured. 7. The device of claim 6, further comprising providing an index of the second low speed physical channel and the second high speed physical channel to a coordinator of the first wireless network. The device of claim 6, further comprising providing device identification information for switching the first channel to the second channel. The device of claim 6, wherein the coordinator of the first wireless network notifies a device in the first wireless network of a list of devices that perform the channel switching.

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