JP4988937B2 - Communication 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 wireless communication, and more specifically to a communication method for handover and implicit handover in a wireless network.

  Various devices are often used in the vicinity, and it may be necessary to use these devices in conjunction with each other. However, it is somewhat inconvenient to connect a large number of devices to each other by wire, and the applications of the devices are often not compatible with each other. If wireless technology is used for communication, it is possible to remove cables such as cables between the devices, and these devices can form a network and exchange data information directly through the wireless network between the devices. become. Any digital device such as a computer, PDA, notebook, digital TV, camcorder, digital camera, printer, microphone, speaker, headset, barcode reader, display, mobile phone can be used as a device that can communicate over a wireless network. Is possible.

  Further, in order to communicate through a wireless network, an apparatus that functions to control resource allocation and distribution between devices constituting the network is required. When the control device cannot perform such a control function, a process for making the control function performed by another device constituting the network is required. In addition, even when a device having better conditions for performing the control function than the current control device joins the network, a process of transferring the control function to the newly joined device is necessary.

  In addition, before the process of transferring the control function is finished, there may be a situation in which the power supply of the control device is suddenly interrupted, or the control device moves and moves out of the network formation distance. In such a situation, if there is no device that can continue the above control function, it cannot respond to a resource allocation request of a device that is communicating on the network, and timing control becomes impossible. As a result, a device communicating through the network cannot transmit or receive any more data, which eventually leads to a fatal problem that the network is not maintained.

  In view of the above-described problems of the conventional technology, the present invention provides a method for continuously maintaining a control function so that smooth wireless communication is performed.

  In addition, in view of the above-described problems of the conventional technology, the present invention provides a method for continuously maintaining a network adjustment function so that smooth wireless communication can be performed.

  A device attempting to communicate over a wireless network searches for a channel in a band for performing communication, and checks whether or not an existing network exists. This device can communicate by joining an existing network, or can create a new network by itself. In the case of forming a new network, the device selects a channel having a better environment based on the information acquired in the search and investigation processes, and broadcasts a control information packet through the selected channel.

  Even if a network including the control device is already formed, the control device may not be able to perform the control function depending on the user's needs and surrounding circumstances. In such a case, smooth communication of the network must be ensured through the process of transferring the control function to another device. Further, even when a device more suitable for performing the control function than the current control device joins the network, it is preferable to transfer the control function to the newly joined device for smoother communication.

  The transfer of the control function to another device after the network is formed as described above is called a handover. According to an embodiment of the present invention, a handover method is provided. In particular, a method is provided for determining a device that requests a handover according to a priority order for a predetermined control function.

  Further, according to another embodiment of the present invention, when a device that controls communication resources of each device in a wireless network system ends the function without performing the process of transferring the control function, the control function is restored. A method for enabling continued communication is disclosed. In the present embodiment, when the control function is suddenly terminated, the recovery or the implicit handover means that the control function in the network is maintained and restored.

A preliminary handover process may be performed before performing a handover or recovery operation. The preliminary handover process is a method in which a current coordinator transmits information necessary for handover and / or information necessary for performing a coordination function (coordinator relevant information) to a device to be handed over, and a device that receives the information. It means a process of storing information necessary for the handover and / or information necessary for performing the adjustment function.
For example, the present invention provides the following items.
(Item 1)
A communication method in the coordinator of a wireless network including a coordinator and at least one device (Device), comprising:
Transmitting a message requesting handover to a device having the highest priority for the coordination function among the at least one device;
Transmitting information necessary for performing the adjustment function (Coordinator relevant information) to the device;
Receiving a response message including information for accepting handover in response to the handover request message;
Broadcasting a beacon including information notifying that the device has become a new coordinator;
Including a communication method.
(Item 2)
In the step of transmitting a message requesting handover to the device, the device is a device newly joined to the network, and the coordinator receives information on the priority of the device from the newly joined device. The communication method according to item 1, wherein a message requesting the handover is transmitted to the device when the priority is higher than the priority of the coordinator.
(Item 3)
Information necessary for performing the adjustment function includes devices that make up the current network, including reserved channel time information (current requests for devices for CTBs), device performance, device ID, and device power storage status (power save status). The communication method according to item 1, comprising at least one of information relating to the priority order of each device and information relating to the priority order of each device.
(Item 4)
The communication method according to item 1, wherein the beacon includes at least one of information on a new adjuster and information on a time remaining until the adjustment function of the adjuster ends.
(Item 5)
Item 4 further comprising the step of receiving a beacon broadcasted by the device after the last beacon is broadcasted among the beacons broadcasted during the remaining time until the adjustment function of the coordinator ends. The communication method described in 1.
(Item 6)
The method further includes rejecting a predetermined request message transferred by a device constituting the network from the time when the coordinator transfers the first beacon to the time when the device transfers the second beacon. The communication method described in 1.
(Item 7)
A communication method in a wireless network including a coordinator, comprising:
When a device joins the network, receiving information about the priority of the device;
If the priority is higher than the priority of the coordinator, a handover request message including information necessary for performing the coordinating function (Coordinator relevant information) is transferred to the device;
Receiving a response message including information for accepting the handover as a response to the handover request message;
Broadcasting a beacon containing information notifying that the device has become a new coordinator;
Including a communication method.
(Item 8)
8. The communication method according to item 7, wherein the priority order is determined by at least one of the device and the coordinator according to a predetermined evaluation criterion including an apparatus characteristic of the device and a network status.
(Item 9)
Information necessary for performing the adjustment function includes devices that make up the current network, including reserved channel time information (current requests for devices for CTBs), device performance, device ID, and device power storage status (power save status). Item 8. The communication method according to Item 7, including at least one of information on the device and information on the priority order of each device.
(Item 10)
Item 7 further comprising the step of receiving a beacon broadcasted by the device after the last beacon is broadcasted among the beacons broadcasted during the remaining time until the adjustment function of the coordinator ends. The communication method described in 1.
(Item 11)
A method of communicating with a coordinator of a wireless network including a coordinator and at least one device comprising:
Transferring a message requesting a first handover including information necessary for performing an adjustment function (Coordinator relevant information) to a first device having the highest priority among the at least one device;
Receiving a response message including information rejecting handover in response to the first handover request message;
Transferring a second handover request message to a second device having a second priority among the at least one device;
Including a communication method.
(Item 12)
A method of communicating with a coordinator of a wireless network including a coordinator and at least one device comprising:
Transferring a message requesting a first handover including information necessary for performing an adjustment function (Coordinator relevant information) to a first device having the highest priority among the at least one device;
Transferring a second handover request message to a second device having a second priority among the at least one device when a response message to the first handover request message is not received for a certain period of time;
Including a communication method.
(Item 13)
A communication method in a coordinator of a wireless network including a coordinator and at least one device comprising:
Selecting a device having the highest priority among the devices joined to the wireless network as an alternative coordinator;
Sending a message notifying that the device with the highest priority has been designated as an alternate coordinator;
Transmitting the information necessary for performing the adjustment function (Coordinator relevant information) to the device having the highest priority;
Including
A communication method in which a device selected as the alternative coordinator operates as a new coordinator in the wireless network when the beacon cannot be received from the coordinator at the expected beacon reception time.
(Item 14)
Item 13. The item according to Item 13, wherein the device characteristics for determining the priority include at least one of the number of other devices accessible to the device, the time during which the power of the device is maintained, and the transfer power. Communication method.
(Item 15)
A method of communicating with a specific device of a wireless network including a coordinator and at least one device comprising:
Receiving a backup message from the coordinator indicating that it has been selected as an alternative coordinator;
If the beacon cannot be received from the coordinator at the expected beacon reception time, transferring the beacon to the wireless network; and
Including a communication method.
(Item 16)
After receiving the above backup message,
Receiving a beacon including information (Coordinator relevant information) necessary for performing the adjustment function from the coordinator;
The communication method according to item 15, further comprising: storing information necessary for performing the adjustment function.
(Item 17)
16. The communication method according to item 15, wherein the specific device is determined based on a priority order for the adjustment function.
(Item 18)
Item 18. The item according to Item 17, wherein the device characteristics for determining the priority include at least one of the number of other devices accessible to the device, the time during which the power of the device is maintained, and the transfer power. Communication method.
(Item 19)
Item 18. The communication method according to Item 17, wherein the beacon broadcasted by the alternative coordinator includes information on the new coordinator.
(Item 20)
A method of communicating with a specific device of a wireless network including a coordinator and at least one device comprising:
Receiving a backup message from the coordinator indicating that it has been selected as an alternative coordinator;
If the beacon cannot be received from the coordinator at the expected beacon reception time, a message is sent to the coordinator to confirm whether the coordinator can continue the adjustment function;
Broadcasting a beacon to the wireless network if a message responding to the confirmation message cannot be received within a predetermined time; and
Including a communication method.
(Item 21)
Item 21. The communication method according to Item 20, wherein the predetermined time is a random access time block (RATB).
(Item 22)
A wireless network communication method including a coordinator and one or more devices,
Receiving a priority list for adjustment functions from the coordinator;
When the device having the highest priority in the priority list cannot receive a beacon at a set timing, broadcasting a beacon to the network at the next beacon transfer timing;
Including a communication method.
(Item 23)
23. A method according to item 22, wherein the broadcast beacon includes information about a new coordinator.

  According to an embodiment of the present invention, communication can be smoothly performed over a wireless network. In particular, there is an effect that communication can be performed without interruption without being greatly affected by the situation of the specific device. In addition, the device that performs the adjustment function is not limited to a specific device, and an effect that the device can be flexibly changed depending on the situation is obtained. Also. A new adjuster is selected in consideration of the priority order for the adjustment function, and the optimum device can be operated as a new adjuster.

  Further, according to another embodiment of the present invention, it is possible to perform communication smoothly over a wireless network. In particular, there is an effect that communication can be performed without interruption without being greatly affected by the situation of the specific device. Further, in determining an alternative adjuster, it is possible to select a more suitable device and to achieve efficient communication.

It is a figure which shows the example of WVAN comprised by many devices. It is a figure which shows the protocol hierarchical structure embodied in the device of WVAN. 4 is a flowchart illustrating a process according to a preferred embodiment of the present invention. FIG. 5 shows a process according to another preferred embodiment of the present invention. 6 is a flowchart illustrating an example of an alternative adjuster determination method according to another preferred embodiment of the present invention. 6 is a flowchart illustrating another example of an alternative regulator determination method according to another preferred embodiment of the present invention.

  According to an embodiment of the present invention, a communication method in the coordinator of a wireless network including a coordinator and at least one device (Device) has the highest priority for the coordinating function among the at least one device. Transmitting a message requesting handover to a higher device, transmitting information necessary for performing a coordination function (Coordinator relevant information) to the device, and information accepting handover for the handover request message Receiving a response message including: and broadcasting a beacon including information indicating that the device has become a new coordinator.

  In the step of transmitting a message requesting handover to the device, the device is a device newly joined to the network, and the coordinator receives information on the priority of the device from the newly joined device. If the priority is higher than the priority of the coordinator, a message requesting the handover can be transmitted to the device.

  In addition, the information necessary for performing the adjustment function configures the current network including reserved channel time information (current requests for devices for CTBs), device performance, device ID, and device power saving status (power save status). At least one of information on a device to be performed and information on priority of each device.

  In addition, the beacon may include at least one of information on a new adjuster and information on a time remaining until the adjustment function of the adjuster ends.

  Here, the method further includes receiving a beacon broadcasted by the device after the last beacon broadcasted during the remaining time until the adjustment function of the coordinator ends. be able to.

  The method may further include rejecting a predetermined request message transferred by a device configuring the network from the time when the coordinator transfers the first beacon to the time when the device transfers the second beacon.

  As another embodiment of the present invention, a communication method in a wireless network including a coordinator includes receiving information on the priority of the device when the device joins the network, and the priority is a priority of the coordinator. If it is higher than the rank, a handover request message including information necessary for performing an adjustment function is transferred to the device, and a response message including information for accepting the handover is received as a response to the handover request message. And broadcasting a beacon including information notifying that the device has become a new coordinator.

  Here, the priority order may be determined according to a predetermined evaluation criterion including at least one of the device and the coordinator including device characteristics and network status of the device.

  In addition, the information necessary for performing the adjustment function configures the current network including reserved channel time information (current requests for devices for CTBs), device performance, device ID, and device power saving status (power save status). At least one of information on a device to be performed and information on priority of each device.

  The method may further include receiving a beacon broadcasted by the device after the last beacon is broadcast among the beacons broadcast during the remaining time until the adjustment function of the coordinator ends. Can do.

  According to another embodiment of the present invention, a communication method in the coordinator of a wireless network including a coordinator and at least one device is performed by adjusting the first device having the highest priority among the at least one device. Transferring a message requesting a first handover including information necessary for performing a function; receiving a response message including information rejecting a handover with respect to the first handover request message; and Transferring a second handover request message to a second device having the second priority among the devices.

  According to another embodiment of the present invention, a communication method in the coordinator of a wireless network including a coordinator and at least one device is performed by adjusting the first device having the highest priority among the at least one device. Transferring a message for requesting a first handover including information necessary for performing a function, and a response message for the first handover request message is not received for a certain period of time, a second priority among the at least one device. Transferring a second handover request message to a second device having a priority.

  According to another embodiment of the present invention, in a communication method using a coordinator and a coordinator of a wireless network including at least one device, a device having the highest priority among the devices joined to the radio network is substituted for adjustment. Selecting a device, transmitting a message notifying that the device having the highest priority is designated as an alternative coordinator, and providing information necessary for performing the adjustment function to the device having the highest priority. The device selected as the alternative coordinator operates as a new coordinator in the wireless network if it cannot receive the beacon at the expected beacon reception time from the coordinator.

  Here, the device characteristics for determining the priority may include at least one of the number of other devices that can be accessed by the device, the time during which the power of the device is maintained, and the transfer power.

  In still another embodiment of the present invention, a communication method in a specific device of a wireless network including a coordinator and at least one device receives a backup message indicating that the coordinator has been selected as an alternative coordinator. And transferring a beacon to the wireless network if the beacon cannot be received from the coordinator at the expected beacon reception time.

  Here, after receiving the backup message, the method includes receiving a beacon including information necessary for performing the adjustment function from the coordinator, and storing information necessary for performing the adjustment function. Further can be included.

  Here, the specific device may be determined based on a priority order for the adjustment function. The characteristics of the device that determines the priority may include at least one of the number of other devices that can be accessed by the device, the time during which the power of the device is maintained, and the transfer power. In addition, the beacon broadcast by the alternative coordinator may include information regarding the new coordinator.

  In still another embodiment of the present invention, a communication method in a specific device of a wireless network including a coordinator and at least one device receives a backup message indicating that the coordinator has been selected as an alternative coordinator. And if the beacon cannot be received from the coordinator at the expected beacon reception time, transmitting a message confirming whether the coordinator can maintain the adjustment function to the coordinator; and the confirmation message for a predetermined time. Broadcasting a beacon to the wireless network if a message that responds to cannot be received. Here, the predetermined time may be a Random Access Time Block (RATB).

  As yet another embodiment of the present invention, a communication method in a wireless network including a coordinator and one or more devices includes receiving a priority list for an adjustment function from the coordinator, Broadcasting a beacon to the network at the next beacon transfer timing when a device having a high priority cannot receive a beacon at a set timing. Here, the broadcast beacon may include information on a new coordinator.

(Example)
The above-described objects, configurations and other features of the present invention will become apparent from the following detailed description based on the accompanying drawings. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiment described below is an example in which the technical features of the present invention are applied to a WVAN (Wireless Video Area Network) which is a kind of wireless network. WVAN is a wireless network that provides a throughput of 4.5 Gbps or more so that a 1080p A / V stream can be transferred without compression at a short distance of 10 m or less using a frequency band of 60 GHz.

  FIG. 1 is a diagram illustrating a WVAN made up of a large number of devices. WVAN is a network configured for data exchange between devices located in a certain space. The WVAN includes two or more devices 10 to 14, and one of these devices operates as a coordinator 10. In configuring a wireless network between these devices, a large number of devices must share a predetermined radio resource. In order to allow these devices to share radio resources without collision, the coordinator 10 performs radio resource allocation and scheduling.

  This coordinator can transmit and receive data through at least one channel as a normal device, in addition to the function of allocating resources so that the devices constituting the network can communicate. In addition, functions such as clock synchronization, network association, and maintaining bandwidth resources can be performed.

  WVAN supports two types of physical layers (PHYs). That is, WVAN supports HRP (high-rate physical layer) and LRP (low-rate physical layer). 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 to transfer isochronous data streams, asynchronous data, MAC commands, and A / V control data through unicast connection. . The LRP supports a directional or omni-directional mode, and is used to transfer beacons, asynchronous data, MAC command words including beacons through unicast or broadcast. The HRP channel and the LRP channel share a frequency band and are used by being divided by the TDM method.

  Hereinafter, an example of a super frame structure used in the above-described WVAN will be described. Each super frame includes an area in which a beacon is transferred, a reserved channel time block, and an unreserved channel time block. A beacon is periodically transmitted to identify the introduction part of each superframe. This beacon packet includes management and control information of scheduled timing information WVAN. The devices can exchange data on the network through timing information and management / control information included in the beacon. In addition, for the purpose of transferring an emergency control / management message, a contention-based control period (CBCP) is included following the beacon. This competition-based control section is also referred to as a random access time block (RATB). The section length of the RATB is set so as to set a certain critical value (mMAXCBCPLen) and not exceed this critical value.

  FIG. 2 is a diagram illustrating a protocol layer structure implemented in a WVAN device. Referring to FIG. 2, each device included in the WVAN can be divided into at least two layers according to its functions, and generally includes a PHY layer 21 and a MAC layer 20. The device includes an individual that manages each layer, and an individual that manages the MAC layer is referred to as MLME (MAC Layer Management Entity) 200, and an individual that manages the PHY layer is referred to as PLME (PHY Layer Management Entity) 210. The device also includes a device management entity (DME) 220 that collects status information of each device and plays a role of a control path between the host and the wireless device. Messages exchanged between different hierarchies are called primitives.

  WVAN begins with the coordinator broadcasting a beacon. The device can communicate by receiving a channel time block for data exchange through a subscription procedure with the coordinator.

  Next, a method for performing communication for handover according to an embodiment of the present invention will be described first.

  FIG. 3 is a flowchart illustrating a process according to a preferred embodiment of the present invention.

  An arbitrary device forms a network by broadcasting a beacon, and becomes a coordinator in the network. If this coordinator leaves the network or the power is cut off and no further adjustment functions can be performed, a handover is performed. The coordinator selects other devices that make up the network. In this case, the selected device must be capable of at least the adjustment function.

  When selecting whether to request handover from any of the devices constituting the network, it is possible to determine the priority of each device and select a device in a better environment. That is, the coordinator receives information on the priority order for the adjustment function of the devices included in the network, uses the priority order information for the adjustment function at the time of handover, and selects a device in an optimal situation as a new coordinator. . The priority for the adjustment function is determined by determining evaluation criteria for time and place, and taking into consideration the characteristics of the device with respect to the evaluation criteria.

  That is, how long each device is operated (long-life time feature), how much power is left, whether it is a battery or AC power, how many devices can transfer control messages, etc. (network- Each device can determine a priority number for its own adjustment function in consideration of a coverage frame). The coordinator receives priority information (number) for the adjustment function of each device, forms a list, and stores the list. A list constructed using the priority order information for the adjustment function can be referred to as a CCD (Coordinator Capable Device) list.

  It is preferable that the coordinator transfers the request message to the device with the highest priority as described above, rather than transferring the request message to any device when transferring the handover request message. That is, when the handover request message is preferentially transferred to a device having a higher priority according to the priority for the adjustment function, the adjustment function can be performed within a range where an optimum device is possible.

The DME of the coordinator sends MLME_COORDINATOR-HANDOVER. The req primitive is transferred (S300). Then, the MLME of the coordinator transfers a handover request message (Coordinator-handover request) to the MLME of the selected device (S310).
After transferring the handover request message, the coordinator can transfer information necessary for handover (Handover relevant information) and / or information necessary for performing the coordination function (Coordinator relevant information).

  For example, the channel time information reserved in the current network (the current request from the device for CTBs), information on the time remaining until the current coordinator passes the adjustment function (for example, the number of remaining beacons or the beacon interval) Number of devices), device performance, device ID, and information on the devices that make up the current network including the power save status of the devices (power save status), information on the adjustment function priority of each device, etc. were selected along with the handover request message It can be transferred to a device and used when deciding whether or not this device will perform a handover. In addition to these pieces of information, any information necessary for handover can be transferred together with a message requesting handover.

  Even when there is no request by the device, transferring the handover request message and the information necessary for performing the handover together not only reduces the amount of packets (data) to be transferred but also simplifies the procedure. There is. An example of the MAC command word format included in this handover request message is shown in Table 1 below.

Through the 'Breaking-in period' field of Table 1, information about the time remaining until the device that has received the handover request message starts operating as a new coordinator can be found. Then, through the 'Timeout' field, information regarding a certain period of time during which the device that has received the handover request message must transfer the handover response message to the handover request message is known. In addition, information on reserved channel time is provided through the 'Reserved Schedule' field in Table 1, information on devices constituting the network is provided through the 'Device List' field, and priority information for the adjustment function is provided through the 'CCD List' field. Recognize.

  The MLME of the device that has received the handover request message notifies MLME-COODIATOR-HANDOVER. The ind primitive is transferred to the DME (S320). The selected device determines whether to perform an adjustment function on the handover request message and forwards the handover response message. That is, the DME of the selected device is sent to MLME as MLME-COODINATOR-HANDOVER. The rsp primitive is transferred (S330). The MLME of the selected device transfers the handover response message (Coordinator-Handover response) to the MLME of the coordinator (S340). An example of the format of the MAC command word included in the handover response message is shown in Table 2.

The command format for the handover response message in Table 2 includes a 'Reason code' field. This reason code represents information regarding whether or not to accept to become a new coordinator for the handover request message. The coordinator knows the success / failure of the handover request message using the reason code.

  It is preferable that a handover response message corresponding to the handover request message is received within a predetermined time after the handover request message is transferred. Accordingly, the coordinator transfers a handover request message and activates a timer set for a certain time, and stops the timer operation when a response message is received before the timer is completed (S350). The coordinator can transfer a handover request message including information on a certain time, and a device that has received the handover request message can transfer a handover response message within a certain time (see Table 1). . However, if the response message is not received until the timer is completed, the handover request is unsuccessful. Therefore, the handover request message is transferred again to another device configuring the network. The MLME of the coordinator informs the DME that the handover response message has been received by MLME-COODINATOR-HANDOVER. The cfm primitive is transferred (S360).

  The DME of this coordinator sends MLME-BEACON. The req primitive is transferred (S370). Then, MLME of the coordinator broadcasts a beacon to the network (S380). When the coordinator succeeds in the handover request, the coordinator transmits information including information on the new coordinator, the CCD list, and the performance of the devices constituting the current network when the next beacon is transferred.

  An example of an information element (IE) format relating to information transferred by being included in a beacon will be described as follows. Depending on the MAC command word or beacon configuration, it can be transferred including information on which IE to use, and the message is transferred in the form of a defined IE. IE format indicating information indicating priority number (CCD list), IE format indicating information on device capability (capability) constituting the current network (Device Capability list), information on new coordinator and determined device (New coordinator) An example of an IE format representing (Information) will be described with reference to the following table.

  Table 3 shows an example of an IE format representing information (prioritized CCD list) representing priority numbers.

The IE format representing the prioritized CCD list includes information indicating the length of the IE format (IE length). This length is n if the number of devices capable of performing the adjustment function (coordinator capable devices: CCD) is n. ^* 2 (octets). Table 4 shows an example of the CCD list block field configuration in detail.

Referring to Table 4, the CCD list block field includes a CCD list block including identification information (CCD ID) of each CCD and information regarding the priority number of the corresponding kCCD.

  Table 5 is an example of an IE format that represents information (Device Capability list) related to the performance of the devices constituting the current network.

The IE format in Table 5 also includes information indicating the length of the IE format (IE length). This length is n ^* 3 (octets) if the number of devices (CCDs) that can be adjusted is n. Can be. Table 6 shows an example of the MAC Capability Block field configuration in detail.

Referring to Table 6, the MAC Capability Block field includes device identification information (Device ID) and a MAC performance bitmap (MAC Capability Bitmap) including information on device performance for the devices constituting the network. An example of this MAC Capability Bitmap configuration will be described in detail using Table 7.

Referring to Table 7, MAC Capability Bitmap is assigned bit by bit to represent information on channel time reservation and information for fast connection (Fast Link Recommendation). Each bit is assigned to represent the transmitting / receiving side of HRP (High Rate PHY) channel communication.

  Table 8 is an example of an IE format representing information (New Coordinator Information) about a new coordinator and a determined device.

In the case of this IE format, information indicating the length of the IE format (IE length), identification information of the new coordinator and the determined device (New coordinator)
ID) and information about the time remaining until the current coordinator transmits the last beacon (eg, Remaining Breaking-in period).

The beacon relates to the time remaining until the new coordinator operates to inform when the new coordinator and the determined device will perform the coordinating function or when the new coordinator performs the coordinating function. Information can be transferred. In this case, a 'Remaining Breaking-in period' field can be used. If the coordinator receives a handover response message and the remaining breaking-in period is n until the coordinating function is finished, it transmits a beacon including information of 'breaking-in period = n', and the next Beacon is' br
A beacon including information of eaking-in period = n−1 ′ is transferred. The last beacon includes information “breaking-in period = 0”, and the new coordinator receiving this information transmits the beacon from the next beacon transfer timing.

  These pieces of information are included in the beacon and transferred by the current coordinator according to the IE format described above. An example of a beacon message format including these pieces of information is shown in Table 9 below.

Referring to Table 9, the beacon message includes not only information related to beacon control information and CBCP end time, but also IE format information related to information necessary for the remaining fields, and these necessary information can also be transferred. For example, the IE shown in Table 8 may be inserted into the IE1 field, and information regarding the new coordinator and the determined device (New Coordinator Information) may be transferred. In addition, the IE shown in Table 3 above can be inserted into the IEm field to transfer the information indicating the priority number (prioritized CCD list). Information (Device Capability list) can be transferred.

  The MLME of the device that received this beacon notifies MLME_BEACON.NET to inform the DME that the beacon has been received. The ind primitive is transferred (S390, S395). After receiving the last beacon transmitted by the current coordinator, the DME of the new coordinator receives MLME-BEACON. The req primitive is transferred to the MLME (S396). Then, MLME of the new coordinator broadcasts a beacon to the network (S397). Upon receiving this beacon, the current coordinator notifies MLME-BEACON. The ind primitive is transferred to the DME (S398).

  For stable handover, the current coordinator confirms that a beacon broadcast by the new coordinator is received for a certain period of time after transferring the last beacon. That is, after transferring the last beacon, the beacon broadcast by the new coordinator is preferably received within a certain time. Therefore, the current coordinator forwards the last beacon and activates a timer that is set for a certain period of time, stops the timer operation if a beacon message is received before this timer completes, and takes the role of coordinator. The process ends (S399). However, if the beacon message is not received until the timer is completed, it means that the handover process has failed, and therefore, the handover request message is forwarded again to other devices constituting the network, and the handover process is resumed. Do. Even when a handover request or a handover process fails, it is preferable to select another device using information on priority. That is, it is preferable to send the handover request message again to the device with the second highest priority.

  The current coordinator rejects a request message (for example, a channel time allocation request message, a join request message, etc.) transferred by another device during the time from when the handover permission response message is received until the last beacon is transferred. It is preferable to do.

  Hereinafter, according to another embodiment of the present invention, when a control function is suddenly terminated, a recovery or an implicit handover method that allows the control function in the network to be maintained and recovered. explain.

An example of the recovery method is a method in which a new control device is determined in advance before the recovery process is performed, and then the new control device performs recovery. Hereinafter, a device determined to be a new control apparatus is referred to as an alternative controller or an alternative coordinator (SCD). If the alternative coordinator notices that the control function is abnormal, it forwards a request message that can confirm whether the original control device is continuing or has completed its function. If the response message cannot be received from the original control device even after the lapse of the predetermined time, the alternative coordinator newly functions as a control device in the network.

  FIG. 4 is a flowchart illustrating a process according to another preferred embodiment of the present invention. As shown in FIG. 1, the WVAN includes a large number of devices 10 to 14, and any one of these devices operates as a regulator 10. In FIG. 4, only some devices are shown for the sake of clarity.

  Referring to FIG. 4, the coordinator DME requests MLME-BEACON. The req primitive is transferred (S400). Then, the MLME of the coordinator transfers the beacon to the MLME of the device configuring the WVAN (S401). The MLME of the device that has received the beacon notifies MLME-BEACON.NET that notifies the DME of each device that the beacon has been transferred. The ind primitive is transferred (S402, S403). Through this beacon scheduling information, the devices constituting the WVAN can exchange data with other devices. When the power of the current coordinator is cut off (S404), or when the current coordinator is out of the WVAN area and beacon broadcasting is not possible any more, the devices in the WVAN will beacon at the scheduled timing. It becomes impossible to receive (S405, S406). A case where a scheduled beacon is not transferred is expressed as 'beacon lost'.

  In WVAN communication, a substitute coordinator (SCD) is determined in advance in case the coordinator suddenly becomes unable to perform the adjustment function. If the device determined as the alternative coordinator (hereinafter referred to as “alternative coordinator”) cannot receive the beacon (S406), the DME of the alternative coordinator transmits a confirmation request message to the MLME. Request CTB-TIME-IE. The req primitive is transferred (S407). Then, the MLME of the alternative coordinator responds to the MLME of the current coordinator with a confirmation request message CTB-TIME-IE. req is transferred (S408).

  In other words, the alternative coordinator transmits a confirmation request message when the beacon cannot be received from the current coordinator. The alternative coordinator may determine that the current coordinator cannot perform its coordinating function if no response message for the request message is received.

  It waits for a predetermined time until a response to the confirmation request message is received (S409). If no response message is transferred from the current coordinator at this predetermined time, the alternative coordinator starts to operate as a new coordinator for WVAN. The DME of the alternative coordinator is MLME-BEACON. For transferring a beacon to MLME at the next beacon transfer timing as a new coordinator. The req primitive is transferred (S410). Then, MLME of the alternative coordinator broadcasts a beacon on the network (S411). The beacon that is transferred first may be configured to include information about the new coordinator (S411). This broadcast beacon is received by the MLME of each device, and MLME-BEACON. The ind primitive is transferred to the DME of each device (S412).

  An embodiment of a time standard for transferring the confirmation request message (CTB-TIME-IE.req) and waiting for a response message will be described in detail as follows. A predetermined timer function can be used. That is, it is possible to set a waiting time, a timer is operated before or after the confirmation request message is transferred, and the timer is ended after the set time has elapsed.

  Also, preferably, the coordinator can use the above super frame structure for timing control information related to channel time resources. If the alternate coordinator does not receive the beacon at the timing when the beacon must be transmitted, the timing is sent to the current coordinator during RATB (S409) to request timing information known from the beacon that has not been received. Forward the information request message. Also in the recovery process, the confirmation request message (CTB-TIME-IE.req) is transferred using RATB (S409). If the alternative coordinator does not receive the beacon at the timing when the beacon must be transferred, the confirmation request message (CTB-TIME-IE.req) is transferred during the RATB (S409) (S408).

  FIG. 5 is a flowchart illustrating an example of an alternative adjuster determination method according to another preferred embodiment of the present invention. Hereinafter, an example of how the current coordinator determines an alternative coordinator prior to the recovery process will be described with reference to FIG. Such a method of determining an alternative coordinator prior to the recovery process can be regarded as an example of a pre-handover process.

  The coordinator selects an arbitrary device from among a large number of devices constituting the WVAN. However, the selected device must be a device that can perform at least the adjustment function. The DME of the coordinator sends MLME-BACKUP. The req primitive is transferred (S500). Then, the MLME of the coordinator transfers the backup request message (Back-up Request) transfer to the MLME of the selected device (S502). This backup request message is a message for requesting that the current coordinator select an arbitrary device, and that the device performs recovery as an alternative coordinator. Table 10 below shows a format of a MAC command (command) that can be used when transferring the backup request message.

The command format for the backup request message in Table 10 includes a field related to the device list. This device list is an information list related to devices constituting the current network. By transferring the device list in the backup request message, it can be used to determine whether the selected device is an alternative coordinator.

  Since a response message to the backup request message is preferably received within a certain time, the elapse of the certain time can be checked using a timer. That is, a timer with a fixed time is activated before transferring the backup request message (S501). This timer may be activated at the same time as or after the request message is transferred. The activated timer completes its operation when a set time has elapsed and informs that a certain time has elapsed. In addition, the current coordinator may transfer a backup request message including information related to a predetermined time, and the device that has received the backup request message may transfer the backup response message within a predetermined time.

  The DME of the device that has received the backup request message before the timer is completed, that is, before the predetermined time elapses, transmits an MLME-BACKUP. Transfer rsp primitive. (S504). The MLME of this device transfers a backup response message (back-up Response) to the MLME of the coordinator (S505). The format of the MAC command word that can be used when transferring this backup response message is presented in Table 11 below.

The command format for the backup response message in Table 11 includes a field related to the reason code. This reason code represents a result of whether or not to accept the backup request message as an alternative coordinator. The current coordinator knows the success / failure of the backup request message using the reason coat.

When this backup response message is received, the timer stops operating before it is completed (S511). The coordinator MLME then notifies the DME that the backup response message has been received. The cfm primitive is transferred (S506). If a successful backup response message is forwarded, the device is determined to be an alternate coordinator. The MLME of the coordinator forwards the beacon to the MLME of the device determined as the alternative coordinator (S508). The device determined as the alternative coordinator stores information included in the transferred beacon so that the coordinating function can be performed as a new coordinator after the recovery process is completed (S510).
According to another embodiment, rather than selecting an arbitrary device from among a large number of devices and transferring a backup request message, the priority for the adjustment function of the device is determined and selected in consideration of this priority. It is more preferable. Each device has a different degree of suitability as a regulator depending on the nature and characteristics of the device. Therefore, the priority order for the adjustment function can be set through information on the characteristics of each device from the devices constituting the network. The set priority information can be made known to the coordinator, or can be shared by the devices constituting the network, so that it is possible to more appropriately determine which device is more suitable as the coordinator.

  According to yet another embodiment, the coordinator receives priority information for adjustment functions from the device and constructs a priority list for these adjustment functions. The priority list for the configured adjustment function is transferred to each device through a notification message. Alternatively, the coordinator receives a message requesting a list from each device and transmits a priority list for the coordinating function through a response message to the message requesting the list. The device that knows the priority list for the transferred adjustment function stores information necessary for performing the adjustment function by itself as an alternative adjuster in case a beacon loss occurs. The device that has become the alternative coordinator can inform the coordinator that the alternative coordinator has been determined through the notification message. If the alternate coordinator fails to receive a beacon from the coordinator, it will forward the beacon itself and act as a new coordinator.

  Features that can be taken into account in determining the priorities may include the number of other devices accessible by the location of each device, the duration of the power source, the output power, and the like.

  FIG. 6 is a flowchart illustrating a process of an alternative regulator determination method according to still another preferred embodiment of the present invention. The selection method shown in FIG. 6 is a case where a successful backup response message for the backup request message transferred by the coordinator is not transferred. In FIG. 6, for the sake of simplicity, the hierarchical structure of each device is not shown, but only the MLME transfer message of the device is shown. Similarly, in this case, there is a need to exchange signals between the hierarchical structures. It is self-explanatory.

  Referring to FIG. 6, the coordinator transmits a backup request message (Back-up Request) to an arbitrary first device (S601). The method for checking whether the backup response message is transferred from the first device for a certain period of time is the same as the method presented in FIG. That is, the timer operates before transferring the backup request message, and the timer is completed when a predetermined time elapses (S600, S602). In addition, the coordinator can transfer a backup request message including information about a predetermined time, and a device that has received the backup request message can transfer a backup response message within a predetermined time. If the backup response message cannot be received from the first device within a certain time or if a backup response message of “failure” is received, the alternative coordinator result process for the first device has failed. The coordinator transfers the backup request message (Back-ip Request) to the other second device again (S604). The subsequent determination method for the second device may be the same as the method presented in FIG. 4 (S603 to S608).

  Also in this case, the priority order information for the adjustment function between the devices can be used. That is, the backup request message is first transferred to the device having the highest priority, and if the backup response message cannot be received or if a failed backup response message is received, the device having the second highest priority. The backup request message (Back-up Request) is transferred to the server again. In this way, the alternative coordinator can be selected in consideration of the priority order for the coordinating function, and communication between networks can be performed more efficiently.

  According to an embodiment of the present invention, communication can be smoothly performed over a wireless network. In particular, there is an effect that communication can be performed without interruption without being greatly affected by the situation of a specific device. The device performing the adjustment function is not limited to any specific device, and there is an effect that it can be flexibly changed depending on the situation. In addition, there is an effect that a new adjuster is selected in consideration of the priority order for the adjustment function, and an optimum device can operate as a new adjuster.

  Further, according to another embodiment of the present invention, communication can be performed smoothly over a wireless network. In particular, there is an effect that communication can be performed without interruption without being greatly affected by the situation of a specific device. In addition, there is an effect that a more suitable device can be selected in determining an alternative adjuster, and efficient communication becomes possible.

  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.

  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.

  The present invention is applicable to wireless communication. More specifically, the present invention can be applied during communication for handover and implicit handover in a wireless network.

Claims (13)

A method of performing handover in a regulator in a wireless network, in the wireless network, high-speed physical channel and slow physical channel is used for communication, including a single device even the wireless network without small, said method Is
Receiving information related to device priority from the device when the device joins the wireless network;
Based on the information received from the device, the priority of the device is higher than the priority of the regulator, and transmitting a handover request message to the device,
Receiving a response to the handover request message from the device;
Broadcasting a first beacon on the low-speed physical channel, the first beacon identifying information indicating that the device will become a new coordinator of the wireless network, and the handover occurs Including a number of information indicating the number of beacons previously broadcast by the coordinator;
Broadcasting one or more beacons corresponding to the number indicated by the number information on the low-speed physical channel , each of the one or more beacons including an updated number of information. the number of information the update, the said regulator before the handover occurs indicates the number of remaining beacons transmitted is the update contained in the last beacon in said one or more beacons And the number of information is set to “0”. Priority of said device, based on the characteristics of the device, is determined by the least even before Symbol device or the regulator, the method according to claim 1. The handover request message includes a handover-related information, the handover-related information includes at least information associated with the stored channel time blocks, or information relating to the characteristics of devices including the wireless network The method of claim 1. Broadcast the last beacon in multiple beacon, after the regulator has completed the adjustment function of the regulator, further comprising a receiving child a second beacon broadcast by the device, according to claim The method according to 1. The response, the device, the includes information indicating that it is ready to take over as the new coordinator of the wireless network, the method described in 請 Motomeko 1. The method of claim 1, wherein the number of information is included in a field of an information element included in each of the one or more beacons. A method for performing handover in a device in a wireless network, wherein a high speed physical channel and a low speed physical channel are used for communication in the wireless network, the wireless network including a coordinator and at least one device, The method is
Sending information related to the priority of the device to the coordinator when the device joins the wireless network;
And that based on the information sent to the regulator, the priority of the device, wherein when higher than the priority of the regulator, which receives a handover request message from the coordinator,
Sending a response to the handover request message to the coordinator;
Receiving a first beacon on the low-speed physical channel, the first beacon identifying information indicating that the device will become a new coordinator of the wireless network, and before the handover occurs Including a number of information indicating the number of beacons broadcast by the coordinator,
Receiving one or more beacons broadcast by the coordinator on the low-speed physical channel, wherein the number of the one or more beacons corresponds to the number of beacons indicated by the number information; and, each of said one or more beacons comprises a number of updated information, the updated number of information indicates the number of remaining beacons the regulator before the handover takes place are transmitted And the updated number of information included in a last beacon among the one or more beacons is set to “0”. The handover request message includes a handover-related information, the handover-related information includes at least information associated with the stored channel time blocks, or information relating to the characteristics of devices including the wireless network The method according to claim 7. Receiving the last beacon in multiple beacon broadcast by the regulator, after the regulator has completed the adjustment function of the regulator, further comprising broadcasting a second beacon, claim 8. The method according to 7. The response, the device, the includes information indicating that it is ready to take over as the new coordinator of the wireless network, the method described in 請 Motomeko 7. The method of claim 7, wherein the number of information is included in a field of an information element included in each of the one or more beacons. A coordinator in a wireless network, wherein a high speed physical channel and a low speed physical channel are used for communication in the wireless network, the wireless network including at least one device, the coordinator comprising:
Receiving information related to device priority from the device when the device joins the wireless network;
Based on the information received from the device, the priority of the device is higher than the priority of the regulator, and transmitting a handover request message to the device,
Receiving a response to the handover request message from the device;
Broadcasting a first beacon on the low-speed physical channel, the first beacon identifying information indicating that the device will become a new coordinator of the wireless network, and the handover occurs Including a number of information indicating the number of beacons previously broadcast by the coordinator;
Broadcasting one or more beacons corresponding to the number indicated by the number information on the low-speed physical channel, each of the one or more beacons including an updated number of information. the number of information the update, the said regulator before the handover occurs indicates the number of remaining beacons transmitted is the update contained in the last beacon in said one or more beacons The number of information is set to “0”, and the regulator is configured to do the following. A device in a wireless network, wherein a high speed physical channel and a low speed physical channel are used for communication in the wireless network, the wireless network including a coordinator and at least one device, the device comprising:
Sending information related to the priority of the device to the coordinator when the device joins the wireless network;
And that based on the information sent to the regulator, the priority of the device, wherein when higher than the priority of the regulator, which receives a handover request message from the coordinator,
Sending a response to the handover request message to the coordinator;
Receiving a first beacon on the low-speed physical channel, the first beacon identifying information indicating that the device will become a new coordinator of the wireless network, and before the handover occurs Including a number of information indicating the number of beacons broadcast by the coordinator,
Receiving one or more beacons broadcast by the coordinator on the low speed physical channel, wherein the number of the one or more beacons corresponds to the number indicated by the number information ; each of the one or more beacons comprises a number of updated information, the updated number of information shows the number of remaining beacons the regulator before the handover takes place are transmitted, The updated number of information included in a last beacon among the one or more beacons is set to “0”.