JP2009171407A - Radio network system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small-scaled network which reduces procedures required for being participated in the network and remarkably reduces loads in time and in resource required for establishing or operating a PAN. <P>SOLUTION: A radio network system includes a coordinator C and a plurality of nodes AP, ED being managed by the coordinator C. Each of the nodes AP, ED includes a plurality of fixed access points AP and an end device ED that is a mobile capable of making ad-hoc to these access points AP, and the nodes AP, ED and the coordinator C preset and prestore therein a PN ID that is such a network identification as recognizing the nodes AP, ED and the coordinator C each other, a communication condition such as an ID that is a device identification, and communication information. When or after the node AP, ED is initiated, the node calls the communication information ans the like, thereby being participated in a network NW without exchanging communication information with the coordinator C. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a wireless network system, such as a personal area network, which is configured to be as simple as possible by reducing the load on resources and to contribute to smooth communication.

Recently, one of personal area networks (hereinafter abbreviated as “PAN”) that enables short-range wireless communication is compliant with IEEE 802.15.4 as introduced in Patent Document 1. What is called Zigbee is known.
In this network system, a large number of nodes are usually connected wirelessly under a coordinator that manages the entire network. When the network is established, the coordinator and the node each execute a start function (start sequence), and then execute a sequence for exchanging communication information such as a device ID and a frequency channel necessary for control as illustrated in FIG. Yes.

  What is shown in the figure is a so-called non-beacon mode called pull-type data transmission.

  Here, first, the coordinator makes a beacon request on a frequency channel to be communicated as a scan (step T1). When receiving a beacon request on a frequency channel that can be received by the terminal, the terminal transmits a beacon (step T2).

  Then, the terminal makes a data request including information on its own address (Mac address) under a predetermined communication channel. The destination is a broadcast without specifying an address (step T3). This is because the coordinator's address is unknown at this point.

  When the coordinator receives this, it recognizes and stores the communication channel for the terminal and the address of the terminal, and returns an acknowledgment (hereinafter abbreviated as “Ack”) using the communication channel and address (step T4). ) Subsequently, the PAN ID and the coordinator address are transmitted (step T5).

  By receiving this, the terminal recognizes and stores the PAN ID and coordinator address, and returns Ack using the communication channel and address (step T6).

  The coordinator waits for Ack, assigns an ID to the terminal, and transmits a participation request (step T7).

  The terminal receives this and returns Ack (step T8).

  Through the above, the exchange sequence of the communication information such as the mutual ID and address is completed, and thereafter, the terminal can communicate with the coordinator.

In order to implement such a protocol related to startup and exchange of communication information, a control unit mainly composed of a microprocessor is mounted on a storage unit (including an OS kernel) including various RAMs and ROMs. The module is called and executed sequentially.
JP 2005-136984 A

  However, the operation of establishing such a PAN seems to be simple at first glance, but when there are many terminals (devices) and the communication conditions such as addresses and communication channels are unknown, a large number of communication information exchange sequences are used. It is necessary to scan the terminals, acquire them, and assign the device ID of each terminal. For this reason, there exists a problem which becomes a big load for a coordinator or a node.

  In addition, since the terminal is often created on the assumption that it moves, the communication capability is limited to a short distance. Therefore, even if the network is established once, there is a high possibility that the coordinator loses (lost) the terminal. Therefore, measures are taken when the terminal is lost, or on the contrary, a mechanism that allows new terminals to participate, for example, the coordinator periodically changes the channel and executes the scan command to reestablish the PAN. There is a problem that the resources of the terminal are further consumed for establishing the PAN. In addition, since it takes time to establish the PAN, there is a risk that communication may not be in time when many terminals are concentrated.

  As described above, this type of network reduces the load on the coordinator and nodes by limiting to short-distance communication. In particular, while expecting nodes to be inexpensive, power-saving, and operating for a long time, they are actually coordinators. In addition, it is necessary to mount a high-spec CPU and a large-capacity memory on each node, and it is difficult to say that size reduction and cost reduction are sufficiently achieved.

  It is an object of the present invention to provide a wireless network system that effectively solves these problems.

  In order to achieve this object, the present invention takes the following measures.

  That is, the wireless network system of the present invention comprises a wireless network by a coordinator and a plurality of nodes managed by the coordinator, and each of the nodes is installed at a plurality of fixed access distances that can be hopped. Communication conditions and communication information including network identification and device identification, etc., which can be mutually recognized between the node and the coordinator. Can be set and stored in advance in each node and coordinator so that the node can participate in the network without exchanging communication information with the coordinator by calling up the communication information at the time of starting or after starting. It is characterized by comprising. The device identification includes a Mac address and the like in addition to the device ID.

  With this configuration, it is not necessary to exchange communication information for participating in the network between the coordinator and the node at the time of activation or after activation, and the activation can be speeded up. In addition, since the activation sequence is simplified, it is possible to effectively reduce resources for that purpose. In addition, a multi-hop network is usually configured such that all nodes are fixed or movable, but the present invention includes a node consisting of an access point that is a fixed node and an end device that is a mobile node, and the end device is the largest. Since it is possible to ad hoc to the nearby access point at any time, it is possible to effectively reduce the risk that the coordinator loses sight of the end device while assuming that the end device moves and using the multi-hop function.

  In order to obtain the above basic effects, the end device can be configured to exchange communication information between the access point and the end device each time when ad hoc to the access point. The access point is arranged so as to form a tree topology with the coordinator as a base point, and the access point stores in advance communication information necessary for communication with an adjacent access point. There is a configuration in which communication information regarding an adjacent access point is received from the access point when the point is ad hoc, and ad hoc to the adjacent access point is realized at the destination based on the communication information.

  The communication information in this case can be ad hoc as long as the adjacent access point is identified, but in order to enable quick ad hoc, the adjacent access point can receive the communication information with the adjacent access point. It is preferable to include information on the frequency channel.

  When communication information of the next access point is given by such a relay, it is impossible to have information for ad hoc to the access point first. Therefore, in order for some of the access points to function as reception access points when the end devices first ad hoc, communication conditions unique to the reception access points are set in advance, and the end devices Reception communication information for communicating with the reception access point is stored in advance, and when the communication request is made after the end device is activated, the end device extracts the reception communication information, and based on this, the end access information is sent to the reception access point. It is effective that the communication request is made.

  Such reception access points are preferably interspersed intermittently among many access points.

  In this case, if the communication condition is set for each reception access point, it is unclear what communication condition the nearest reception access point is. In order to solve this problem, it is desirable to set common communication conditions for all the access points for reception.

  In the case of a tree structure, each access point has two adjacent access points on the upstream side and the downstream side except for the end. In this case, in order to solve the problem that it is unclear which access information the access point gives communication information about which adjacent access point, or which communication information the end device uses, the access point is connected to the end device. On the other hand, the first mode for assigning communication information related to the upstream adjacent access point and the second mode for assigning communication information related to the adjacent adjacent access point on the downstream side can be configured to operate the end device. It is effective to switch between the first and second modes according to the characteristics.

  And as one aspect | mode of the concrete implementation for this mode switching, what is comprised so that the coordinator may transmit the switching command for switching a mode according to time with respect to each access point is mentioned. .

  Alternatively, as another aspect of the specific implementation for the mode switching, among the reception access points that first receive a communication request from the end device, the reception access point that belongs to the downstream side of the tree is the first one A flag representing the mode is generated, and the reception access point belonging to the upstream side of the tree generates a flag representing the second mode, and this flag is chained to the adjacent access point via the end device, An adjacent access point may be configured to selectively give communication information related to an upstream access point or communication information related to a downstream access point to an end device according to the flag.

  Since the present invention is configured as described above, the access point is arranged along the school commuting path, the end device is carried or attached to the child, and the end device and the end device each time the end device is ad hoc to the access point. By configuring the data including the device ID of the access point to be sent to the coordinator, the coordinator can effectively collect data related to whereabouts at the time of attending school by simply giving the child an end device with few resources. It is possible to secure communication effectively even if school children are crowded when going to and from school.

  Since the present invention has the configuration described above, the PAN can be reduced by first reducing the procedure until joining the network, and by providing a certain communication law when a specific pattern exists in the movement of the terminal. A new and useful wireless network system that greatly reduces the time and resource load required for establishment and operation of the network and thereby achieves the purpose and effect of the small-scale network described above is newly provided. be able to.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  This embodiment is applied to an elementary school commuting path and aims to manage the movement of a child with a school management server through a node and a coordinator in order to confirm the safety of the child.

Therefore, the wireless network system of this embodiment is
In accordance with the E E E 80 2.1 5.4 standard specification, as shown in FIG. 1, a number of nodes are connected wirelessly under a single coordinator C that manages the entire network NW. Build a to peer WPAN. The node has a large number of fixed access point APs (AP100, AP101,... AP200, AP201...) Equipped with a relay function necessary for multihop to the coordinator C, and a large number of movements that can be ad hoc to these access points AP. The role is shared with the end device ED which is the body. Hereinafter, the term “node” refers to both the access point AP and the end device ED. The coordinator C, nodes AP, and ED hold communication information such as frequency channels and IDs necessary for communication with the communication partner when performing communication management after the start sequence (start function) is executed. It will be necessary. In this embodiment, the nodes AP and ED are immediately connected to the network instead of executing a communication information acquisition sequence starting with device ID assignment and frequency channel information acquisition as shown in FIG. Establishing a system capable of participating in NW, omits exchange sequence of communication information such as ID and frequency channel.

  Hereinafter, specific description will be given with reference to the drawings. 2 to 4 functionally illustrate the resources of the coordinator C, the access point AP, and the end device ED.

A device 1 to be a coordinator C shown in FIGS. 1 and 2 is arranged in a school. In this network, there is only one coordinator C, I
EE EE 80 2.1 5.4 A storage unit consisting of various RAMs and ROMs that store various programs and data, PAN IDs, etc. necessary for them to play the role of network management as a PAN coordinator compliant with the standard specifications 11, a control unit 12 mainly composed of a microprocessor that calls a module (part of program or program) or data from the storage unit 11 and executes predetermined sequence processing, etc., and transmission / reception as an interface for transmission / reception with the outside Part 13. At the time of activation, the control unit 12 calls the activation module (activation function) 1a stored in the storage unit 11. Then, the communication management module 1b for managing communication with the nodes AP and ED is started up after activation. In the case of a normal coordinator configuration, according to the communication management module, the nodes AP and ED are scanned as shown in FIG. 8 to execute a communication information exchange sequence such as the frequency channel and ID of each node AP and ED, After storing the acquired communication information, a state is established in which communication with each of the nodes AP and ED is possible on the PAN.

  On the other hand, in the device 1 constituting the coordinator C of this embodiment, all or a part of the modules that execute sequences relating to acquisition of frequency channels, ID allocation, etc., are deleted or stopped in the communication management module 1b. Instead, it is necessary to set a fixed ID and a predetermined frequency channel in the coordinator C, access point AP and end device ED in advance, and include device identification and channel identification such as ID for each node AP and ED. Communication information is stored in the storage unit 11. When the communication management module 1b performs a communication operation, communication information such as the frequency channel and ID of the corresponding device is extracted. For this reason, the control part 12 can establish immediately the communication possible state with node AP, ED only by calling the communication management module 1b.

  Such a communication management module 1b is usually incorporated in a protocol stack portion for a data link layer, a network layer, and a transport layer, which are located in a relatively lower layer of the OSI reference model. Here, the communication management module 1b is described in what is generally referred to as an application programming interface or the like, and the function can be stopped, deleted, or changed by rewriting a part thereof. The same method is used for communication modules 2b and 3b in the access point AP and end device ED described later when the function is stopped, deleted, or changed.

  As shown in FIG. 1, a management server SV is connected to the coordinator C via a telecommunication network such as Ethernet (registered trademark) E, and various settings, operations, and management for the coordinator C and nodes AP and ED are performed. To be able to do that. The server SV has general hardware resources.

  On the other hand, the access points AP shown in FIG. 1 and FIG. 3 are arranged at a hoppable distance so as to form a cluster tree topology with respect to the coordinator C and based on the electric field strength. The tree is set so as to extend radially from the school along the school route of the child. In the figure, two trees extend from the coordinator C, but the number is not limited, and there may naturally be a branching point as shown. Particularly in recent years, school routes are often limited and patterned from the viewpoint of crime prevention, and the root of the tree along the school route is relatively easy to establish.

The device 2 serving as the access point AP is
EE EE 80 2.1 5.4 In order to play a role as a router compliant with the standard specifications, a storage unit 21 including various RAMs and ROMs storing various programs and data necessary for the router, and the storage unit 21 A control unit 22 mainly composed of a microprocessor that calls programs and data from and executes predetermined sequence processing and the like, and a transmission / reception unit 23 serving as an interface for transmission / reception with the outside. At the time of activation, the control unit 22 calls the activation module 2a (activation function) stored in the storage unit 21. And the communication module 2b for starting communication with the coordinator C is started after starting. In the case of a normal router configuration, according to the communication module, as shown in FIG. 8, it is necessary to correspond to the exchange sequence of communication information such as device ID assignment and transmission of PAN ID and coordinator C ID performed by the coordinator C. At this time, the communication information such as the PAN ID and the ID of the coordinator C is acquired and stored, and then a state in which communication with the coordinator C can be established on the WPAN is established.

  On the other hand, in the device 2 constituting the access point AP of this embodiment, all or part of the modules that execute processing corresponding to the communication information exchange sequence performed by the coordinator C in the communication module 2b are deleted or functioned. Instead, communication information such as the frequency channel of the coordinator C, the ID, and the PAN ID is stored in the storage unit 21 in addition to the preset device ID. When the communication module 2b performs a communication operation, communication information such as a frequency channel and ID is extracted. Thereby, the control part 22 can establish the communication possible state immediately with the coordinator C only by calling this communication module 2b.

  The access point AP not only transmits / receives its own message as a router, but also includes a relay module 2c in the storage unit 21 for relaying messages from other nodes AP and ED. In the case of a normal access point configuration, the relay module incorporates a module related to a routing table for establishing a route to the coordinator C through route search, but the relay module 2c of this embodiment is a dynamic module. The function related to the routing function is stopped or deleted. Instead, data originating from other nodes AP and ED is relayed upstream, that is, toward the coordinator C, and data originating from the coordinator C is always relayed downstream, ie, away from the coordinator C. A module part for executing a sequence for performing the relay function is incorporated. For this purpose, at least each access point AP stores communication information such as IDs and frequency channels related to adjacent access points AP located upstream and downstream in advance.

The relay module 2c includes a sequence related to communication when the end device ED is ad hoc. In this embodiment, the relay module 2c performs an operation of delivering the communication information related to the adjacent access point AP to the end device ED. This will be described below after describing the configuration of the end device ED. I
In the E E E 80 2.1 5.4 standard specification, 16 channels are prepared as frequency channels, and a reception frequency channel is set for each access point AP.

  Further, in this embodiment, among the many access points AP shown in FIG. 1, the access point AP (AP100, AP114, AP124, AP200...) Surrounded by the double line is first ad hoced by the end device ED. Is set as a reception access point APx. The reception access points APx are installed so as to be intermittently scattered in a tree composed of a large number of access points AP, and the access point APx at the uppermost stream of the tree is arranged at the school gate. In other words, the reception access point APx has unique communication conditions such as an ID and a frequency channel when ad hoc the end device ED among the relay functions described above are different from those of other general access points AP. It is set. This condition is common to all reception access points APx in the present embodiment. This will also be described below after describing the configuration of the end device.

  The end device ED shown in FIGS. 1 and 4 is used by being carried by a child or attached to a bag or the like.

The device 3 to be the end device ED is I
EE EE 80 2.1 5.4 In order to play a role as an end device compliant with standard specifications, a storage unit 31 including various RAMs and ROMs storing various programs and data necessary for the end device, and the storage unit A control unit 32 mainly including a microprocessor that calls programs and data from 31 to execute predetermined sequence processing and the like, and a transmission / reception unit 33 serving as an interface for transmission / reception with the outside are provided. At the time of activation, the control unit 32 calls the activation module (activation function) 3a stored in the storage unit 31. And the communication module 3b for starting communication with the coordinator C is started after starting. If it is a normal end device, according to the communication module, as shown in FIG. 8, the process corresponding to the device ID assignment and the exchange sequence of communication information such as PAN ID and coordinator ID performed by the coordinator C is executed. When PAN ID and coordinator communication information are acquired and stored, a state in which communication with the coordinator can be established on the WPAN is established.

  On the other hand, in the device 3 constituting the end device ED of this embodiment, all or a part of the modules that execute processing corresponding to the exchange sequence of communication information performed by the coordinator C is deleted or stopped. Instead, communication information relating to network identification and device identification such as the frequency channel, ID, and PAN ID of the coordinator C is stored in the storage unit 31 starting with its own device ID. When the communication module 3b performs a communication operation, the frequency channel and ID are extracted.

  The communication module 3b includes a module portion that executes a sequence necessary for ad hoc to the access point AP. The ad hoc procedure includes a sequence for first ad hoc to the reception access point AP 100 and the like in FIG. 1 and a sequence for switching the ad hoc destination from the access point AP 100 to the access point AP 101 → AP 102. In preparation for the former case, the end device ED stores in advance the communication information corresponding to the above-mentioned unique ID and frequency channel in the storage unit 31 as reception communication information for communication with the reception access point APx. I'm allowed. When the communication module 3b performs a communication operation, communication information such as frequency channels and IDs and reception communication information are extracted. For this reason, the control unit 32 can establish a communicable state with the coordinator C by immediately ad hoc to the access point AP (including APx) simply by calling the communication module 3b. This end device ED can communicate with only the access point AP (including APx) or the coordinator C, and does not have a communication function between the end devices ED.

  FIG. 5 schematically shows a startup procedure of the end device ED. When started, the activation module 3b is called (step 101), and then the communication module is called (step 102). At this point, the device enters a state where it participates in WPAN, and is in a communicable state, that is, an activation end. The activation operation of the access point AP is basically the same.

  The end device ED of this embodiment includes a vibration detection unit 34 to be activated by vibration as shown in FIG. 4, and the control unit 32 enters the activation sequence upon receiving a detection signal from the vibration detection unit 34. In addition, sleep is set when the detection signal from the vibration detection unit 34 is interrupted for a predetermined time or more.

  FIG. 6 shows a sequence based on the above configuration, in which the end device ED ad hoc to the access point AP after activation and switches the ad hoc destination one after another.

  First, the control unit 32 of the end device ED detects a vibration and executes an activation sequence (step S1). This includes calling the activation module 3a and starting the communication module 3b. Next, the frequency channel and ID, which are communication information of the accepting access point APx, are extracted from the storage unit 31, and based on this, a data request is made and a return of Ack is awaited (step S2). The requested data is the frequency channel and ID of the next adjacent access point AP. When the Ack wait timeout is reached, the data request is made again.

  When Ack is returned, an ad hoc state is set (step S3), and the frequency channel and ID of the adjacent access point AP to be communicated next are transmitted (step S4). The communication information relating to the next adjacent access point AP is assigned on the upstream side when going to school, and on the downstream side when leaving school. This function will be described later. When the end device ED returns Ack to this (step S5), the next data request is then made based on the new frequency channel and ID (step S6). Similar to the above, the data request is made again when the Ack wait times out. When Ack is returned from the next access point, it becomes an ad hoc state (S7), and when the frequency channel and ID of the adjacent access point AP are further acquired (S8), Ack is returned to this (S9). Based on this, connection with the next adjacent access point AP is attempted.

  Thus, the end device ED starts from the initial ad hoc to the reception access point APx, and moves along the tree while switching the ad hoc destination to the next access point AP one after another.

  In this embodiment, during this period, at least ad-hoc destination access point AP of the end device ED is configured to transmit at least position data including the IDs of the end device ED and the access point AP to the coordinator C every ad hoc. It is.

  The management server SV connected to the coordinator C stores in advance data relating to the relationship between the ID of each access point and the absolute position of the geography, and the management server SV stores the end device ED and the ad hoc destination access point AP. Both IDs are received, and the data representing the location of the end device ED and the geographical absolute position data are stored or displayed in association with each other.

  In addition, regarding the provision of the communication information related to the next adjacent access point AP described above, in this embodiment, the first mode in which the access point AP provides the communication information related to the upstream adjacent access point AP to the end device ED. Alternatively, a sequence is incorporated in the communication module 2b of the device 2 so that the access point AP operates in any one of the second modes in which the communication information regarding the adjacent access point AP on the downstream side is given. The device 1 of the coordinator C in FIG. 2 incorporates mode switching means (module) 14 that transmits a switching command S for switching the mode according to time to each access point AP. For example, on the basis of noon and midnight, a switching command S such as the first mode is transmitted from midnight to noon, and the second mode is transmitted from noon to midnight.

  Therefore, the access point AP stores the mode information in the storage unit 21 in response to the switching command S transmitted from the coordinator C at a predetermined time, and when there is a data request from the end device ED as shown in FIG. In step S201, the mode information is extracted from the storage unit 21 to determine whether the mode is the first mode or the second mode (step S202). If it is the first mode, the communication information of the upstream access point AP is determined as the end device. If it is the second mode, the communication information of the downstream access point AP is transmitted to the end device ED (step S204).

  As described above, the wireless network system according to the present embodiment includes the coordinator C and the plurality of nodes AP and ED managed by the coordinator C. Each of the nodes AP and ED includes a plurality of fixed access points AP and an end device ED that is a mobile that can be ad hoc to these access points AP, and between the nodes AP and ED and the coordinator C. Are set and stored in advance in each node AP, ED, and coordinator C, such as PAN ID, which is a network identification that can be recognized by each other, and ID, which is a device identification. However, by calling these communication information at the time of activation or after activation, the network NW can be joined without exchanging communication information with the coordinator C.

  With this configuration, it is possible to start immediately from the data request without executing a communication information exchange sequence for participating in the network NW between the coordinator C and the nodes AP and ED at the time of activation or after activation. , It is possible to speed up the activation. In particular, when a large number of terminals are concentrated, access to the coordinator in a concentrated manner is avoided, so that a situation where communication is not in time can be effectively eliminated. In addition, since the protocol stack is dieted and the activation sequence is simplified, it is possible to effectively reduce resources for that purpose.

  In addition, since the end device ED can only communicate with the access point AP (including APx) or the coordinator C and does not originally have a communication function between the end devices ED and ED, the functions are limited, and the resources of the microprocessor are limited. Is poor. In such an end device, the diet of the protocol keeps the load on the microprocessor small, can be implemented at low cost, and enters the sleep mode when it does not communicate without having a relay transfer function. As a drive, it can be operated effectively over a long period of time.

  Further, a multi-hop network is usually configured by whether all nodes AP and ED are fixed or movable. In this embodiment, the nodes AP and ED are connected to an access point AP that is a fixed node. Since the end device ED is a mobile node, and the end device ED can ad hoc at any time to the nearest access point AP, it is assumed that the end device ED moves and the coordinator C uses the multi-hop function. Can effectively reduce the risk of losing sight of the end device ED.

  As a specific configuration, the access point AP is arranged to form a tree topology with the coordinator C as a base point, and the access point AP stores in advance communication information necessary for communication with the adjacent access point AP. When the end device ED ad hoc to one access point AP, the end device ED receives communication information related to the adjacent access point AP from the access point AP, and the ad hoc to the adjacent access point AP at the destination based on the communication information. It is configured to realize.

  That is, since the end device ED of the present embodiment can specify a movement path to some extent, by arranging the access points AP so as to form a tree topology along the path, the end device ED can access each access point AP along the tree. You can expect to go through. Then, since the end device ED acquires the communication information of the next access point AP in advance, it is possible to perform an operation of quickly switching the ad hoc destination.

  In particular, since the information on the frequency channel that can be received by the adjacent access point AP is included in the communication information with the adjacent access point AP, the occurrence of congestion is reduced by changing the frequency channel between the adjacent access points AP and AP. In such a case, the end device ED can be quickly synchronized with the frequency channel AP.

  In addition, in order for some of the access points AP to function as reception access points APx when the end device ED first ad hoc, communication conditions specific to frequency channels, IDs, and the like are preset in the reception access points APx. In addition, reception communication information for communicating with the reception access point AP is stored in the end device ED in advance, and the end device ED is used for the reception when a communication request is made after the end device ED is activated. The communication information is taken out, and based on this information, a communication request is made to the reception access point APx.

  That is, at the time of the first ad hoc, communication information for the next access point AP has not been acquired yet. Therefore, the reception access point APx that communicates based on the specific communication condition as described above is installed, and the reception access information APx that corresponds to the specific communication condition is given to the end device ED, and the reception access point APx is set. If it is made to search, it can be made to ad hoc effectively to the access point AP for reception first.

  Since a common communication condition is set for all reception access points AP, the end device ED can ad hoc to the nearest reception access point AP using the same reception communication information. The configuration and procedure for the can be simplified.

  Furthermore, the first mode in which the access point AP gives communication information related to the upstream adjacent access point AP to the end device ED, and the second mode in which communication information related to the downstream adjacent access point AP is given. Since the first and second modes are switched according to the dynamic characteristics of the end device ED, there is a certain pattern for the movement of the end device ED as in this embodiment. When it can be expected, by setting the system to any mode through such a switching function, switching of the ad hoc destination can be performed more simply.

  In addition, since the coordinator C is configured to issue a switching command for switching the mode according to the time to each access point AP, it is effective for the purpose and application in which the movement pattern of the end device changes depending on the time. Can be adapted.

  Then, the access point AP is arranged along the school route, and the end device ED and the access point AP are identified each time the end device ED is ad hoc to the access point AP. Since the data including the URL is transmitted to the coordinator, the child SV is effectively collected in the server SV via the coordinator C only by holding the end device with few resources to the child. Even if school children are crowded at the time of going to and from school, it is possible to ensure communication and use it for grasping the current location and movement history of the child to effectively demonstrate the child monitoring function.

  The specific configuration of each part is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

  For example, for setting and storing communication conditions and communication information, a Mac address can be directly used in addition to the device ID. In the above embodiment, the network is constructed in conformity with IEEE 802.15.4. However, if the node can be multi-hopped to the coordinator based on the communication conditions and communication information given by default, the specification is limited to such specifications. It is not a thing.

  Further, the communication information can be freely incorporated into the module or called from another ROM or RAM.

  Furthermore, in the above-described embodiment, information on the adjacent access point AP received by the ad hoc end device ED is unknown at a location where the route branches downstream (for example, access point AP102 → access point AP113, AP123). Therefore, it is effective to identify the school route by the device ID of the end device ED. Then, the access point AP at the branch point determines the next access point AP based on the information from the end device ED based on the device ID, and gives communication information such as a corresponding channel and ID. Just keep it.

  In addition, regarding the aspect in which the communication information related to the next adjacent access point AP from the ad hoc destination is given, the reception access point APx belonging to the downstream side of the tree among the reception access points APx that first receive a communication request from the end device ED. (For example, an access point arranged at the end of the school district) generates a flag representing the first mode, and an access point APx for reception belonging to the upstream side of the tree (for example, an access point APx arranged at the school gate) is the first one. It may be configured to generate a flag representing the two modes, and this flag may be provided in a chain manner to the adjacent access point AP via the end device ED. In this way, each adjacent access point AP clearly determines which of the communication information related to the upstream access point AP or the communication information related to the downstream access point AP should be given to the end device ED according to the flag. Therefore, it is possible to cope effectively even when the time of going to and from school is irregular.

The figure which shows the network topology of the radio | wireless network system which concerns on one Embodiment of this invention. The device block diagram of the coordinator which comprises the system. The device block diagram of the access point which comprises the system. The device block diagram of the end device which comprises the system. The flowchart which shows the starting procedure of the end device. FIG. 3 is a sequence diagram showing a procedure when the end device ad hoc to an access point. The flowchart which shows the procedure in which the access point delivers the communication information of an adjacent access point to an end device. The sequence diagram which shows the starting procedure of the conventional wireless network system.

Explanation of symbols

AP ... node (access point)
APx ... Reception access point C ... Coordinator ED ... Node (end device)
NW ... Network

Claims (9)

A wireless network is configured by a coordinator and a plurality of nodes managed by the coordinator,
Each node is composed of a plurality of fixed access points installed at a hop-capable distance and end devices that are ad hoc mobiles to these access points, and the nodes and the coordinator recognize each other. Communication conditions and communication information including possible network identification and device identification are set and stored in each node and coordinator in advance, and the node calls these communication information at startup or after startup so that the coordinator A wireless network system configured to be able to participate in a network without exchanging communication information with the network. The access point is arranged so as to form a tree topology with the coordinator as a base point, and the access point stores communication information necessary for communication with an adjacent access point in advance. 2. The wireless network according to claim 1, wherein when a point is ad hoc, communication information regarding an adjacent access point is received from the access point, and ad hoc to the adjacent access point is realized at a destination based on the communication information. system. The wireless network system according to claim 2, wherein the communication information with the adjacent access point includes information on a frequency channel that can be received by the adjacent access point. In order to function as a reception access point when the end device first ad hoc, a part of the access point has communication conditions specific to the reception access point set in advance, and the end device has Reception communication information for communicating with the access point is stored in advance, and when the communication request is made after the end device is activated, the end device extracts the reception communication information, and based on this, the end device communicates with the reception access point. 4. The wireless network system according to claim 2, wherein the wireless network system is configured to make a request. 5. The wireless network system according to claim 4, wherein a common communication condition is set for all reception access points. A configuration in which the access point can take a first mode in which communication information related to an upstream adjacent access point is given to an end device and a second mode in which communication information related to a downstream adjacent access point is given 6. The radio network system according to claim 4, wherein the first mode and the second mode are switched according to the dynamic characteristics of the end device. 7. The wireless network system according to claim 6, wherein the coordinator is configured to send a switching command for switching modes according to time to each access point. Of the reception access points that first receive a communication request from the end device, the reception access point that belongs to the downstream side of the tree generates a flag representing the first mode, and the reception access point that belongs to the upstream side of the tree A flag representing two modes is generated, and this flag is chained to the adjacent access point via the end device, and each adjacent access point communicates with the upstream access point or downstream according to the flag. The wireless network system according to claim 6, wherein the communication information regarding the access point is selectively given to the end device. The access point is placed along the school route, the end device is carried or attached to the child, and the data including the device ID of the end device and the access point is sent to the coordinator every time the end device ad hoc to the access point. The wireless network system according to claim 2, configured as described above.

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