JPWO2016167121A1 - Wireless communication system, parent device, child device, and wireless connection method - Google Patents

Abstract

In a wireless communication system, a wireless communication system, a parent unit of the wireless communication system, a slave unit of the wireless communication system, and a wireless connection method executed in the wireless communication system, which suppress interference of a wireless channel between a plurality of wireless communication devices The purpose is to provide. The master unit of the radio communication system determines a radio channel in advance and transmits a notification signal including an identifier. The slave unit switches the radio channel to receive the notification signal, and the identifier included in the notification signal and the own device are set in advance. When the received identifier is equal, a response signal for wireless connection to the wireless communication network is transmitted to the parent device that is the source of the notification signal.

Description

  The present invention relates to a wireless communication system, a base unit of the wireless communication system, a slave unit of the wireless communication system, and a wireless connection method executed in the wireless communication system.

  In recent years, a wireless communication system in which a parent device that constructs a wireless communication network and a child device connected to the wireless communication network perform wireless communication has been widely used. Among them, for example, for the purpose of remotely sensing an object that is difficult for humans to directly sense, the communication standard IEEE 802.15. It is a specific low-power radio system defined by 4 / 4e / 4g (for example, Non-Patent Document 1). Hereinafter, the specific low power radio system is abbreviated as a special small radio system.

  Of the wireless communication devices that make up the extraordinary wireless system, a coordinator and a PAN are wirelessly connected to a master unit that constructs a communication standard IEEE 802.15.4 PAN (Personal Area Network), and the same PAN A slave that communicates with another wireless communication device connected to the host is called a host, and a device that performs wireless communication with the slave as an alternative to the master is called a router. Furthermore, the coordinator, the host, and the router are collectively referred to as a node.

  In the conventional extraordinary radio system, the procedure from when the coordinator and the host are activated until the host starts wireless connection to the PAN constructed by the coordinator is as follows. In the setting of the data link layer at the time of activation, the coordinator performs selection of a radio channel for constructing the PAN and determination of a PAN ID (PAN Identifier) for identifying the PAN. First, the coordinator checks available radio channels that are not detected in the surroundings or have a weak detected radio wave level. Then, the coordinator transmits a beacon request signal using the wireless channel. If there is no response to a beacon signal from another coordinator using the same radio channel in response to this beacon request signal, the coordinator that transmitted the beacon signal uses the same radio channel in the surrounding area. Is determined to exist, and the radio channel is selected. The coordinator determines the PANID along with the selection of the radio channel. Furthermore, the network ID is set in advance in the coordinator, and the beacon signal transmitted by the coordinator includes the network ID. On the other hand, the host detects a PAN and selects a radio channel in setting the data link layer at startup. The host sequentially switches to an available radio channel and transmits a beacon request signal in order to detect a PAN present in the surroundings. The coordinator receiving the beacon request signal from the host responds by transmitting a beacon signal. By receiving the beacon signal at this time, the host can detect the PAN and grasp the PANID and the wireless channel for connecting to the PAN. Then, the host obtains the network ID included in the beacon signal at this time, determines whether or not it is equal to the network ID that the host wants to connect to, and if it is equal, wirelessly connects to the coordinator constructing the PAN. Send a signal for.

TTC (Telecommunication Technology Committee) standard, JJ-300.10 Home network communication interface for ECHONET Lite

  As described above, in the conventional extra-small radio system, in order to wirelessly connect to the PAN of the coordinator, the host transmits a beacon request signal using all available radio channels. Therefore, for example, in a wireless communication system in which a host installed in a plurality of mobile units selects one from a plurality of coordinators and communicates, the host uses a wireless channel in a state where nodes are crowded as the mobile unit moves. When a beacon request signal is transmitted while switching, the beacon request signal is a signal that is broadcast or broadcast, so a node that uses the same radio channel as the beacon request signal causes interference to frequently retransmit the signal. There is a risk of it. This affects the wireless connection of other hosts and the wireless communication between nodes, such as delay.

  The above-described problem also applies to a wireless communication system that includes a parent device that constructs a wireless communication network while using a plurality of wireless channels, and a child device that performs wireless communication by connecting to the wireless communication network.

  The present invention is for solving the above-described problem, and suppresses radio channel interference between a plurality of radio communication apparatuses, a radio communication system, a radio communication system parent device, a radio communication system slave device, and radio An object is to provide a wireless connection method executed in a communication system.

  The present invention relates to a slave unit in which a first identifier is set in advance, a master unit that establishes a wireless communication network using a predetermined wireless channel and wirelessly communicates with the slave unit that is wirelessly connected to the wireless communication network, The base unit transmits a notification signal including a second identifier, the slave unit receives the notification signal by switching the radio channel, and the set first unit When one identifier is equal to the second identifier included in the notification signal, a response signal for wirelessly connecting to the wireless communication network is transmitted to the parent device that is the transmission source of the notification signal. A wireless communication system.

  In addition, the present invention is a parent device that constructs a wireless communication network of a wireless communication system and wirelessly communicates with a child device wirelessly connected to the wireless communication network, and a parent device communication unit that performs the wireless communication with the child device; A radio channel determination unit that predetermines a radio channel to be used in the base unit communication unit, and a broadcast signal generation unit that generates a broadcast signal including an identifier and transmits the broadcast signal via the base unit communication unit. It is a featured master unit.

  Further, the present invention is a slave unit that is wirelessly connected to a wireless communication network of a wireless communication system and wirelessly communicates with a parent device that has constructed the wireless communication network, and a storage unit that stores a preset first identifier; Notification signal from the master unit received via the slave unit communication unit, a slave unit communication unit that performs the wireless communication with the master unit, a radio channel switching unit that switches a radio channel used in the slave unit communication unit, and When the identifier determination unit that determines whether the second identifier included in the storage unit is equal to the first identifier stored in the storage unit and the identifier determination unit are equal, the transmission source of the notification signal A slave unit comprising: a response processing unit that transmits a response signal for wirelessly connecting to the wireless communication network to the master unit via the slave unit communication unit.

  In addition, the present invention provides a network construction process in which a parent device constructs a wireless communication network using a predetermined radio channel, and a notification signal transmission step in which the parent device transmits a notification signal including a second identifier; An identifier setting step for presetting a first identifier in the slave unit, a notification signal receiving step in which the slave unit receives the notification signal by switching the radio channel, and the slave unit is set in the first When it is determined in the identifier determination step that determines that the identifier and the second identifier included in the received notification signal are equal, and in the identifier determination step that the first identifier and the second identifier are equal, A response signal transmitting step in which the slave unit transmits a response signal for performing a wireless connection to the wireless communication network to the master unit that is a transmission source of the notification signal. It is a connection method.

  According to the present invention, in a radio communication system, a master unit determines a radio channel in advance and transmits a notification signal including an identifier, and a slave unit switches the radio channel to receive the notification signal and is included in the notification signal. When the identifier and the identifier set in advance in the own device are equal, a response signal for wireless connection to the wireless communication network can be transmitted to the parent device that is the transmission source of the notification signal. As a result, when the slave unit is wirelessly connected to the wireless communication network of the master unit, the slave unit switches to a wireless channel that can be used by the slave unit and does not notify the master unit of signals, and the slave units that do not interfere with each other. Since signals can be transmitted / received to / from the base unit using the radio channel, an effect of suppressing radio channel interference can be obtained.

  The objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description and the accompanying drawings.

1 is a system configuration diagram showing a door opening / closing system in Embodiment 1. FIG. It is a block block diagram which shows the function part of a coordinator. It is a block block diagram which shows the function part of a host. It is a sequence diagram which shows a process until a host is wirelessly connected to PAN of a coordinator. It is a frame block diagram which shows the structure of the MAC frame of the beacon request signal which a coordinator transmits. FIG. 10 is a sequence diagram showing processing until the host wirelessly connects to the PAN of the coordinator in the second embodiment. It is a frame block diagram which shows the structure of the MAC frame of the beacon signal which a coordinator transmits. FIG. 10 is a system configuration diagram showing a door opening / closing system in a third embodiment.

<Embodiment 1>
An example in which Embodiment 1 of the present invention is applied to a station platform and a train door opening and closing system will be described. FIG. 1 is a system configuration diagram showing a door opening and closing system in the first embodiment. The door opening and closing system is a system that opens and closes the platform door and the train door when the train stops on the platform or when the train departs from the platform. In the door opening and closing system, the train crew and station staff start the door opening and closing control based on the information that the fixed position stop sensor installed on the platform detects the stop of the train, and according to this door opening and closing control, the platform door and It opens and closes in conjunction with the train door.

  In FIG. 1, platforms P <b> 1 to P <b> 4 are station platforms that get on and off the train. In FIG. 1, the platform P1 indicates that the train R1 has stopped, the platform P2 indicates that the train R2 is about to stop, the platform P3 indicates that the train R3 passes, and the platform P4 indicates that the train is passing. Indicates a situation that does not exist. It is assumed that the direction indicated by the traveling direction U in the figure is the upward direction of the train, the train R1 and the train R3 are traveling in the upward direction, and the train R2 is traveling in the downward direction.

  The home door G1 is a home door installed on the platform P1, and the home door G2 is a home door installed on the platform P2. The home door G1 shows an open state, and the home door G2 shows a closed state.

  The train door E1 is a door installed on the right side in the traveling direction of the train R1, and the train door E2 is a door installed on the left side in the traveling direction of the train R1. The train door E3 is a door installed on the right side in the traveling direction of the train R2. Train door E1 shows an open state, and train doors E2 and E3 show a closed state.

  The fixed position stop sensors D1 to D4 are sensors installed on the platforms P1 to P4, respectively, for detecting information regarding the displacement of the train, and notifying that the train has stopped at a fixed position or is about to stop. Can do.

  The coordinator 1 is a wireless communication device that operates as a parent device installed in each platform, and the host 2 is a wireless communication device that operates as a child device installed in each train. In FIG. 1, a coordinator 1 is installed on each of the platforms P1 to P4, and a host 2 is installed on each of the trains R1 to R3. The coordinator 1 and the host 2 that perform wireless communication are installed at positions where the mutual radio waves reach. The radio channel used by the coordinator 1 is set so as not to interfere with other coordinators 1.

  As described above, the coordinator 1 constructs a PAN that is a wireless communication network, and the host 2 can connect to the PAN to perform wireless communication with a node belonging to the PAN. The node here refers to a coordinator, a router, and a host.

  2 and 3 are block configuration diagrams showing functional units of a wireless communication device that constitutes the door opening and closing system. FIG. 2 is a block configuration diagram showing functional units of the coordinator 1. FIG. 3 is a block configuration diagram showing functional units of the host 2.

  The coordinator 1 includes a coordinator control unit 3, a coordinator communication unit 4, a radio channel determination unit 6, a notification signal generation unit 7, a connection processing unit 8, and a ground communication unit 9.

  The coordinator control unit 3 is a functional unit for controlling each functional unit of the coordinator 1 and performing an operation as a master unit. The door opening / closing system of the present invention detects door stop by a fixed position stop sensor installed on a platform and performs door opening / closing control. The coordinator 1 is used when a train stops or stops. When it is near, transmission of a notification signal for prompting the host 2 to establish a wireless connection to the PAN is started.

  A coordinator communication unit (which is an example of a parent device communication unit) 4 is a functional unit for performing wireless communication with other nodes such as the host 2. Connected to an antenna 5 for transmitting and receiving radio waves.

  The radio channel determination unit 6 is a functional unit that determines a radio channel used by the coordinator 1. After the apparatus is activated, a series of processes for determining a radio channel, such as radio wave detection of a radio channel used by surrounding nodes and transmission of a beacon request signal on the selected radio channel, are performed. Here, each time the apparatus is activated, the radio channel may be selected again and determined, or the same radio channel as that at the previous activation may be selected and determined. Alternatively, the wireless channel to be used may be set in advance, and the wireless channel may be determined by reading the setting at startup.

  The notification signal generation unit 7 is a functional unit that generates a beacon request signal that is a notification signal. The generated beacon request signal includes an identifier for connecting another node to the PAN. As the identifier at this time, information that can be commonly identified between the coordinator 1 and other nodes, such as a host identifier for identifying the host 2 with which the coordinator 1 wants to perform wireless communication, a network identifier for identifying the network, or the like is used. In the present invention, a host identifier is used for each of the first and second identifiers. In addition, the notification signal generation unit 7 may generate a beacon request signal when the radio channel determination unit 6 determines a radio channel to be transmitted.

  The connection processing unit 8 is a functional unit that receives a beacon signal transmitted as a response signal by the host 2 that has received the beacon request signal from the coordinator 1 and performs a series of processes related to the wireless connection of the host 2 to the PAN. is there.

  The ground communication unit 9 is a functional unit for communicating with a ground external device 10 installed outside the coordinator 1.

  The ground external device 10 manages and controls the coordinator 1, notifies the information related to the PAN constructed by the coordinator 1, notifies the information indicating the stop state of the train detected by the fixed position stop sensor, and the coordinator 1 includes the beacon request signal. Notification of a host identifier and transmission / reception of a control signal for performing door opening / closing control are performed. The ground external device (which is an example of the first external device) 10 may be connected to a plurality of coordinators 1 and perform the above-described processing such as management and control on each of the coordinators 1.

  The host 2 includes a host control unit 11, a host communication unit 12, a wireless channel switching unit 14, a storage unit 15, an identifier determination unit 16, a response processing unit 17, and an on-vehicle communication unit 18.

  The host control unit 12 is a functional unit for controlling each functional unit of the host 2 to operate as a slave unit. In the present invention, when the host 2 receives the notification signal from the coordinator 1 and determines that the host identifier included in the notification signal is the same as the host identifier set in the own device, the wireless communication to the PAN is performed. Start the connection.

  A host communication unit (which is an example of a slave unit communication unit) 12 is a functional unit for performing wireless communication with other nodes such as the coordinator 1. It connects to an antenna 13 for transmitting and receiving radio waves.

  The wireless channel switching unit 14 is a functional unit that switches a wireless channel used by the host 2. In order to wirelessly connect to the PAN constructed by the coordinator 1, the wireless channel is sequentially switched to receive a beacon request signal from the coordinator 1. When the identifier determination unit 16 described later determines that the host identifier included in the received beacon request signal is equal to the host identifier set in the own device, the wireless channel switching unit 14 stops switching the wireless channel. Wireless communication is performed using the wireless channel. The procedure for switching the radio channel at this time will be described later. In addition, after the wireless channel switching is completed, the operation returns to the first wireless channel.

  The storage unit 15 is a functional unit that stores a host identifier for identifying the host 2.

  The identifier determination unit 16 is a functional unit that determines whether the host identifier included in the beacon request signal received from the coordinator 1 is equal to the host identifier stored in the storage unit 15. If it is determined that the identifier determination unit 16 is equal, the process proceeds to a process of starting wireless connection to the PAN constructed by the coordinator 1 that is the transmission source of the beacon request signal.

  When the response processing unit 17 receives the beacon request signal and determines that the identifier determination unit 16 is equal, the response processing unit 17 generates a response signal for wireless connection to the PAN constructed by the coordinator 1 that transmits the beacon request signal, It is a functional unit that performs a series of processes related to the subsequent wireless connection.

  The on-vehicle communication unit 18 is a functional unit for communicating with an on-vehicle external device 19 installed outside the host 2.

  An on-vehicle external device (which is an example of a second external device) 19 performs management and control of the host 2, notification of a host identifier stored in the storage unit 15 of the host 2, and transmission / reception of a control signal for performing door opening / closing control. Do. The on-vehicle external device 19 may be connected to a plurality of hosts 2 and perform the above-described processing such as management and control on each host 2.

  FIG. 4 is a sequence diagram showing processing until the host 2 wirelessly connects to the PAN of the coordinator 1. In FIG. 4, the hosts H1 and H2 perform wireless connection to the PANs of the coordinators C1 and C2. The radio channels used by the coordinators C1 and C2 may be set in advance.

  For the sake of explanation, in FIG. 4, the radio channel is represented as CH. The host identifier is expressed as HostID. For example, if the host identifier is 10, it is described as HostID (10). Also, the beacon request signal is expressed as Enhanced Beacon Request (CH, HostID). For example, if the wireless channel that transmitted the beacon request signal is channel 1 and the host identifier is 10, Enhanced Beacon Request (CH (1), HostID). (10)). Also, the beacon signal is expressed as Enhanced Beacon (CH), and for example, if the radio channel that transmitted the beacon signal is channel 1, it is described as Enhanced Beacon (CH (1)). In addition, a series of PANA (Protocol for Carrying Authentication for Network Access) signals transmitted and received between the coordinator 1 and the host 2 is expressed by description starting with “PANA”.

  In process S31, the coordinators C1 and C2 determine the radio channel used by the own device. The procedure for determining the radio channel is as described above. Here, the coordinator C1 determines the radio channel to be used as CH (1), and the coordinator C2 determines the radio channel to be used as CH (3). Note that determination of PANID is omitted. In addition, the hosts H1 and H2 set host identifiers for identifying their own devices. The procedure for setting the host identifier is as described above. Here, the host H1 sets the host identifier to HostID (10), and the host H2 sets the host identifier to HostID (20).

  In process S32, the hosts H1 and H2 perform radio channel switching in order to receive the beacon request signal. Here, the radio channel is first switched to CH (1).

  In process S33, the coordinators C1 and C2 transmit beacon request signals. Since the radio channel of the coordinator C1 is CH (1), the beacon request signal of the coordinator C1 can be received by the hosts H1 and H2. The host H1 determines that the host identifier of the beacon request signal received at this time is equal to the host identifier set in the own device, and starts wireless connection to the PAN of the coordinator C1. On the other hand, the host H2 determines that the host identifier of the beacon request signal received at this time is not equal to the host identifier set in its own device, and discards the received beacon request signal. Further, since the radio channel of the coordinator C2 is CH (3), the beacon request signal of the coordinator C2 cannot be received by the hosts H1 and H2.

  In the process S34, the host H1 transmits a beacon signal, which is a response signal, to the coordinator C1 using CH (1). Subsequently, the host H1 transmits a PANA signal to the coordinator C1. Thereafter, a series of signals for wireless connection to the PAN is transmitted / received between the coordinator C1 and the host H1. When wireless connection is established, wireless communication can be performed between the coordinator C1 and the host H1.

  In the process S35, the host H2 switches to the next wireless channel CH (2) since a predetermined time for switching the wireless channel has elapsed. The coordinator C2 transmits a beacon request signal. Since the radio channel of the coordinator C2 is CH (3), the beacon request signal of the coordinator C2 cannot be received by the hosts H1 and H2 as in the process S33.

  In the process S36, the host H2 switches to the next wireless channel CH (3) since a predetermined time for switching the wireless channel has elapsed. The coordinator C2 transmits a beacon request signal. Since the radio channel of the coordinator C2 is CH (3), the beacon request signal of the coordinator C2 can be received by the host H2. The host H2 determines that the host identifier of the beacon request signal received at this time is equal to the host identifier set in the own device, and starts wireless connection to the PAN of the coordinator C2. On the other hand, the beacon request signal of the coordinator C2 cannot be received by the host H1 as in the process S33.

  In the process S37, the host H2 transmits a beacon signal, which is a response signal, to the coordinator C2 using CH (3). Subsequently, the host H2 transmits a PANA signal to the coordinator C2. Thereafter, a series of signals for wireless connection to the PAN is transmitted / received between the coordinator C2 and the host H2. When wireless connection is established, wireless communication can be performed between the coordinator C2 and the host H2.

  FIG. 5 is a frame configuration diagram showing a configuration of a MAC (Media Access Control) frame of a beacon request signal transmitted by the coordinator 1. The frame configuration F1 is a MAC header portion, the frame configuration F2 is a MAC payload portion, and the frame configuration F3 is a MAC footer portion.

  In the MAC frame of FIG. 5, the position where the coordinator 1 includes the host identifier for identifying the host 2 is “Sub−” following “Type” in the “IE Content” field included in the “Payload IEs” of the MAC payload portion F2. IE Content ", which is the position shown in the frame configuration F4. In the prior art, the position of the frame configuration F4 is unused, but in the present invention, the host identifier is included in order to identify the host 2 with which the coordinator 1 wants to communicate. Note that the frame configuration in FIG. 5 is merely an example, and it is desirable that compatibility with the prior art is maintained even when the frame configuration is different or the host identifier is included at a different position.

  By making the first embodiment of the present invention as described above, the problems of the prior art can be solved.

  First, in the prior art, if the broadcast signal is transmitted while the host 2 does not know the radio channel of the coordinator 1 that performs radio communication and the radio channels are sequentially switched, radio channel interference occurs between nodes. For this interference, it is possible to retransmit a signal that could not be transmitted due to the interference by using a method such as CSMA / CA (Carrier Sense Multiple Access / Collision Avoidance). In particular, when the nodes are densely populated, radio channel interference becomes significant, and there is a first problem that a delay occurs on the order of 100 milliseconds for successful signal transmission.

  Next, when trying to perform wireless communication with a specific host 2 from the side of the coordinator 1, the coordinator 1 needs a means for starting a wireless connection to the PAN of the coordinator 1 with respect to the specific host 2. The technology has a second problem in that there is no means for the coordinator 1 to initiate a specific host 2 wireless connection to the PAN.

  In the present invention, the first problem is that the nodes are in a dense state, and the host 2 does not have a means for preliminarily knowing the radio channel of the coordinator 1 that performs radio communication. The signal is switched and the coordinator 1 transmits a signal using a radio channel different from that of the other coordinator 1 determined in advance. Therefore, the signal is transmitted using the radio channel of the coordinator 1 that the host 2 does not communicate with. Therefore, it is possible to suppress radio channel interference between nodes.

  When the present invention is applied to a door opening and closing system, for example, a coordinator 1 that fixes and uses a preselected radio channel is installed on each platform of each station whose position is fixed. By installing a host 2 that switches channels, the coordinator 1 of each platform at each station transmits a notification signal without interfering with the radio channel, and the host 2 of each train that enters the station switches the radio channel. However, since the notification signal is received and wireless connection is made, even if the host 2 of the stopped train connects wirelessly to the PAN of the coordinator 1 of the platform on the platform of the station where the nodes are densely packed, the coordinator of the platform 1 and the train host 2 perform wireless communication for door opening / closing control. Even Rutoki without signal receiving interference from broadcast signals of the other nodes is delayed, it is possible to operate stably.

  Further, according to the second problem, the coordinator 1 transmits to the host 2 a notification signal including information on a host identifier held by a specific host 2 that wants to perform wireless communication. It becomes possible to start the wireless connection to the PAN for the specific host 2 that has received the message.

  When the present invention is applied to a door opening / closing system, for example, the coordinator 1 installed on the platform P1 in FIG. 1 transmits a notification signal including a host identifier that identifies the host 2 installed on the train R1, and the specific host 2 The wireless connection with can be started. In the door opening / closing system, as an advantage of performing wireless communication by specifying the host 2 from the coordinator 1 side, for example, a fixed position stop sensor is installed on the platform, and the coordinator 1 installed on the platform is the fixed position stop sensor. It is easier to determine when to start communication with the host 2 by using the information of the above, and the platform, which is a ground facility, better understands the operation status of each train than a moving train. It is easy and it is possible to obtain more reliably which train stops on which platform.

  Furthermore, the coordinator 1 controls door opening / closing such as which door of the platform is opened / closed, which door on the left / right side of the train stopped on the platform is opened / closed, and the timing of opening / closing the platform / train doors. Is established by establishing wireless communication with a specific host 2, and the ground external device 10 transmits / receives a control signal to / from a specific on-vehicle external device 19.

  In addition, the fact that the train has left the platform may be detected using the information of the fixed position stop sensor, and communication between the coordinator 1 and the host 2 or the ground external device 10 and the vehicle external device 19 is established. You may judge by the health check performed accompanying it having stopped.

  As described above, in the first embodiment of the present invention, the door opening / closing system has been described as an example. However, the present invention is not limited to the door opening / closing system, and the coordinator 1 installed in a fixed position and the vicinity of the coordinator 1 The present invention can be applied to a wireless communication system that performs wireless communication with a host 2 installed on a moving body that moves or stops. Here, the vicinity is the distance that radio communication radio waves reach. By applying the present invention to such a wireless communication system, the ground external device 10 can suppress the interference of the wireless channel even in a situation where a plurality of nodes exist densely and a plurality of wireless channels are used. Based on the desired conditions, wireless communication is established with the specific host 2 from the coordinator 1 side, and the ground external device 10 and the specific on-vehicle external device 19 are operated in conjunction (in an example of realizing the interlocking means). Is possible).

  In FIG. 2, it has been described that the wireless channel switching unit 14 of the host 2 receives a signal from the coordinator 1 while switching the wireless channel. The procedure for the host 2 to switch the radio channel at this time includes the radio channel switching order and the switching time.

  As the switching order of the wireless channels, for example, it is conceivable to select available wireless channels in ascending order of channel numbers. Further, according to the IEEE 802.15.4 standard, the wireless channel switching time is derived from the calculation formula of 15.36 × (2 to the power of 2 + 1) [milliseconds]. . Here, n is a duration and 0 ≦ n ≦ 14. Depending on the system, taking into account various delays in frame processing, the time obtained by multiplying the time derived from the calculation formula by k may be used as the radio channel switching time. For example, when n = 5 and k = 1.25, 633.6 [milliseconds] obtained by multiplying 506.88 [milliseconds] derived from the calculation formula by 1.25 is set as the radio channel switching time.

  However, if the switching time at this time is long, it takes a long time for the wireless channel of the coordinator 1 scheduled to perform wireless communication to go around. Conversely, if the switching time is short, the notification from the coordinator 1 The signal is missed. Therefore, it is necessary to adjust the switching time so as to establish a wireless connection within a time range permitted by the system based on the number of usable wireless channels and the number of nodes.

  In general, it is desirable that the time required for the host 2 to establish a wireless connection is short. According to the present invention, since radio channel interference between the nodes is suppressed, the wireless connection of the host 2 can be more reliably performed even when the radio channel switching time is shorter than in the conventional technique.

  Further, if the host 2 can grasp in advance the wireless channel used by the coordinator 1 that performs the next wireless communication, the host 2 may preferentially switch to the wireless channel and receive the signal. The time for switching to the radio channel may be longer than that for other radio channels. As a means for the host 2 to grasp the wireless channel of the coordinator 1 in advance, for example, when using a separate communication means between the ground and the train, or when the coordinator 1 and the host 2 perform wireless communication, It is conceivable that the station and the platform where the train of the host 2 stops next is known, and the coordinator 1 notifies the host 2 of the wireless channel to be used in the next wireless communication in advance.

  By grasping the wireless channel to be switched preferentially in this way, for example, switching to the preferential wireless channel first, switching the wireless channel to a preferential wireless channel once every two times, or preferential wireless By taking a longer time for switching to the channel, the time required for the host 2 to establish a wireless connection can be shortened.

  As described above, the present invention suppresses radio channel interference between the nodes and shortens the time required for the host 2 to establish a radio connection as compared with the prior art. Therefore, communication between the coordinator 1 and the host 2 is possible. Can be applied to systems that require immediateness.

  According to Embodiment 1, in a wireless communication system, a master unit determines a wireless channel in advance and transmits a notification signal including an identifier, and a slave unit switches the wireless channel to receive the notification signal and When the included identifier is equal to the identifier set in advance in the own device, a response signal for wireless connection to the wireless communication network can be transmitted to the parent device that is the transmission source of the notification signal. As a result, when the slave unit is wirelessly connected to the wireless communication network of the master unit, the slave unit switches to a wireless channel that can be used by the slave unit and does not notify the master unit of signals, and the slave units that do not interfere with each other. Since signals can be transmitted / received to / from the base unit using the radio channel, an effect of suppressing radio channel interference can be obtained.

  Further, according to the first embodiment, the wireless communication system is a specific low power wireless system, the wireless communication network is a PAN of the specific low power wireless system, the parent device is the coordinator 1 of the specific low power wireless system, and the slave device is A wireless communication system can be configured as the host 2 of the specific low power wireless system. As a result, an effect of constructing a system that communicates with low power utilizing the advantages of the IEEE 802.15.4 standard can be obtained.

  Further, according to the first embodiment, the parent device transmits a notification signal including a host identifier for identifying the child device to the child device, and the child device transmits the host identifier included in the received notification signal to the own device. A response signal can be transmitted by determining whether or not a host identifier that identifies a slave set in advance is equal. As a result, it is possible to obtain an effect that the parent device designates a specific child device and performs wireless communication.

  Further, according to the first embodiment, it is possible to wirelessly connect the slave unit to the radio communication network of the master unit using the notification signal as a beacon request signal and the response signal as a beacon signal. As a result, the use of signals handled by the IEEE 802.15.4 standard provides an effect that the slave unit can be wirelessly connected to the base unit's wireless communication network while ensuring compatibility with the IEEE 802.15.4 standard. .

  Further, according to Embodiment 1, the base unit can include the identifier in the Sub-IE Content of IE Content that is a part of the MAC payload of the beacon request signal. As a result, since an identifier is included in an unused position of a signal handled in the IEEE 802.15.4 standard, a slave unit is wirelessly connected to the base unit's wireless communication network while ensuring compatibility with the IEEE 802.15.4 standard. The effect that can be obtained.

  Further, according to the first embodiment, the base unit is installed with the position fixed, the slave unit is installed on a moving body that moves or stops in the vicinity of the master unit, and the ground external device 10 and the slave that communicate with the master unit The on-vehicle external device 19 that communicates with the machine can be operated in an interlocked manner via wireless communication between the parent machine and the child machine based on conditions desired by the ground external apparatus 10. As a result, wireless communication is established between the parent device and the specific child device triggered by the desired conditions of the ground external device 10, and the ground external device 10 is connected to the specific vehicle via the established wireless communication. An effect of operating in conjunction with the external device 19 is obtained.

  In addition, according to the first embodiment, the master unit is installed on the platform of the station, the slave unit is installed on the train entering the platform on which the master unit is installed, and the ground external device 10 (state grasping) that communicates with the master unit It is possible to control the platform and the train door in conjunction with each other on the basis of the train operation state grasped by (which is an example of means). As a result, on the platform of a station where nodes are densely packed, there is an effect that the parent device and the child device can communicate stably without being affected by the interference of the notification signal from another node. In addition, when the train stops, wireless communication is established between the master unit and the specific slave unit, and the platform and the specific door of the train are linked from the ground or the train via the established wireless communication. Can be opened and closed.

  Further, according to the first embodiment, when the slave unit wirelessly communicates with the parent device wireless channel in advance and receives a notification signal from the parent device, the wireless channel of the parent device that has been previously grasped is given priority. It is possible to switch. As a result, it is easy to receive a notification signal from the parent device that performs wireless communication, and an effect of shortening the time required for establishing wireless communication between the parent device and the child device can be obtained.

<Embodiment 2>
In the first embodiment, a notification signal transmitted from the coordinator 1 to the host 2 is used as a beacon request signal, and a host identifier is included in an unused frame position of the beacon request signal so that a specific host 2 starts a wireless connection. It was. In Embodiment 2 of the present invention, the notification signal transmitted by the coordinator 1 is a beacon signal, and the host identifier is included in the frame position including the network identifier of the beacon signal.

  FIG. 6 is a sequence diagram showing processing until the host 2 wirelessly connects to the PAN of the coordinator 1 in the second embodiment. In FIG. 6, as in FIG. 4, the hosts H1 and H2 make wireless connections to the PANs of the coordinators C1 and C2.

  For the sake of explanation, in FIG. 6, the beacon signal is represented as Enhanced Beacon (CH, HostID). For example, if the wireless channel that transmitted the beacon signal is channel 1 and the host identifier is 10, Enhanced Beacon (CH (1) , HostID (10)). The description of a series of PANA signals, radio channels, and host identifiers transmitted and received between the coordinator 1 and the host 2 is the same as in FIG.

  The process S51 is the same as the process S31 in FIG.

  In process S52, the hosts H1 and H2 perform switching of radio channels in order to receive beacon signals. Here, the radio channel is first switched to CH (1).

  In process S53, the coordinators C1 and C2 are transmitting beacon signals. Since the radio channel of the coordinator C1 is CH (1), the beacon signal of the coordinator C1 can be received by the hosts H1 and H2. The host H1 determines that the host identifier of the beacon signal received at this time is equal to the host identifier set in its own device, and starts the wireless connection to the PAN of the coordinator C1. On the other hand, the host H2 determines that the host identifier of the beacon signal received at this time is not equal to the host identifier set in its own device, and discards the received beacon signal. Further, since the radio channel of the coordinator C2 is CH (3), the beacon signal of the coordinator C2 cannot be received by the hosts H1 and H2.

  In step S54, the host H1 transmits a PANA signal, which is a response signal, to the coordinator C1 using CH (1). Thereafter, a series of signals for wireless connection to the PAN is transmitted / received between the coordinator C1 and the host H1. When wireless connection is established, wireless communication can be performed between the coordinator C1 and the host H1.

  In the process S55, the host H2 switches to the next wireless channel CH (2) since a predetermined time for switching the wireless channel has elapsed. The coordinator C2 transmits a beacon signal. Since the radio channel of the coordinator C2 is CH (3), the beacon signal of the coordinator C2 cannot be received by the hosts H1 and H2 as in the process S53.

  In the process S56, the host H2 switches to the next wireless channel CH (3) since a predetermined time for switching the wireless channel has elapsed. The coordinator C2 transmits a beacon signal. Since the radio channel of the coordinator C2 is CH (3), the beacon signal of the coordinator C2 can be received by the host H2. The host H2 determines that the host identifier of the beacon signal received at this time is equal to the host identifier set in the own device, and starts the wireless connection to the PAN of the coordinator C2. On the other hand, the beacon signal of the coordinator C2 cannot be received by the host H1 similarly to the process S53.

  In the process S57, the host H2 transmits a PANA signal, which is a response signal, to the coordinator C2 using CH (3). Thereafter, a series of signals for wireless connection to the PAN is transmitted / received between the coordinator C2 and the host H2. When wireless connection is established, wireless communication can be performed between the coordinator C2 and the host H2.

  FIG. 7 is a frame configuration diagram showing the configuration of the MAC frame of the beacon signal transmitted by the coordinator 1. The frame configuration F5 is a MAC header portion, the frame configuration F6 is a MAC payload portion, and the frame configuration F7 is a MAC footer portion.

  In the MAC frame of FIG. 7, the position where the coordinator 1 includes the host identifier for identifying the host 2 is “Sub−” following “Type” in the “IE Content” field included in “Payload IEs” in the MAC payload portion F6. IE Content ", which is the position shown in the frame configuration F8. In the prior art, the network identifier is included in the position of the frame configuration F8, but in the present invention, the host identifier is included in order to identify the host 2 with which the coordinator 1 wants to communicate. Note that the frame configuration in FIG. 7 is merely an example, and it is desirable that compatibility with the prior art is maintained even when a different frame configuration is used or a host identifier is included at a different position.

  In addition, in the wireless LAN (Local Area Network) of IEEE802.11 standard, the information for identifying the mobile station with which the wireless connection has been established is added to the beacon signal from the base station, thereby entering the sleep state. There is a method for canceling sleep for a certain mobile station. On the other hand, the host identifier to be included in the notification signal of the present invention is one in which the master unit specifies an unconnected slave unit to perform wireless connection, and in this way, other nodes of different radio channels can be connected. Produces an effect of avoiding interference with a notification signal transmitted by the.

  According to the second embodiment, the slave unit can be wirelessly connected to the master unit's wireless communication network using the notification signal as a beacon signal and the response signal as a PANA signal. As a result, the use of signals handled by the IEEE 802.15.4 standard provides an effect that the slave unit can be wirelessly connected to the base unit's wireless communication network while ensuring compatibility with the IEEE 802.15.4 standard. .

  Further, according to the second embodiment, the master unit can include the identifier in the Sub-IE Content of IE Content that is a part of the MAC payload of the beacon signal. As a result, since the position including the network identifier of the signal handled in the IEEE802.15.4 standard is used, the slave unit is wirelessly connected to the wireless communication network of the parent unit while ensuring compatibility with the IEEE802.15.4 standard. The effect that can be obtained.

<Embodiment 3>
In the door opening and closing systems of the first and second embodiments, one coordinator 1 is installed on each platform, and one host 2 is installed on each train. In Embodiment 3 of the present invention, in the door opening and closing system, a plurality of coordinators 1 are installed on each platform, and a plurality of hosts 2 are installed on each train.

  FIG. 8 is a system configuration diagram showing a door opening and closing system in the third embodiment. In the door opening / closing system of FIG. 8, the hosts 2 are respectively provided in the two vehicles at both ends of the train R1, and the coordinators 1 are respectively provided at the positions of the platforms P1 corresponding to the two hosts 2 of the stopped train R1. Here, the location of the platform corresponding to the host 2 of the stopped train changes because the number of vehicles differs depending on the train, or the host 2 is installed on the three vehicles near both ends and the center of the train, so it is installed on the platform. The number and position of the coordinators 1 to be arranged do not have to be as shown in FIG. 8, and are appropriately installed according to the system.

  As shown in FIG. 8, when a plurality of hosts 2 are installed in accordance with the length of the entire train and the number of vehicles connected, and a plurality of coordinators 1 are installed on the platform corresponding to the hosts 2, for example, between the coordinators 1 and 2 The distance becomes shorter and wireless communication can be performed more stably. In addition, the coordinator 1 and the host 2 that perform wireless communication can be selected in accordance with an increase or decrease in the number of connected trains. In addition, since the wireless communication path can be made redundant, the operation can be continued without stopping in the event of maintenance or failure of the apparatus.

  At this time, the plurality of coordinators 1 installed on the same platform may use the same radio channel or different radio channels. Similarly, a plurality of hosts 2 installed on the same train may use the same radio channel or different radio channels. When the same radio channel is used, radio channel interference can be avoided or a plurality of hosts 2 can be prevented by stopping the transmission of one of the notification signals of the plurality of coordinators 1 so as not to cause radio channel interference. The power consumption may be suppressed without wirelessly connecting any of the above.

  If interference does not occur even if the same radio channel is used on the same platform, a plurality of routers are installed instead of a plurality of coordinators 1 on each platform, and the coordinator 1 communicates with each router. The router may perform wireless communication with each specific host 2 in place of the coordinator 1.

  Management and control of the above-described plurality of nodes are performed by the ground external device 10 and the vehicle external device 19.

  According to the third embodiment, a plurality of slave units are installed in a mobile unit, a plurality of master units are installed corresponding to the slave units, and wireless communication is performed according to the position of the slave unit installed in the mobile unit. It becomes possible to select a parent machine and a child machine. As a result, the distance between the parent device and the child device can be shortened, and an effect of performing wireless communication more stably can be obtained. Further, it is possible to obtain an effect of selecting a parent device and a child device that perform wireless communication according to a change in the shape of the moving body. In addition, the wireless communication path can be made redundant so that the system operation can be continued without stopping in the event of maintenance or failure of the apparatus.

  It should be noted that the present invention can be freely combined with each embodiment and each modification within the scope of the invention, and each embodiment and each modification can be appropriately modified and omitted.

  Although the present invention has been described in detail, the above description is illustrative in all aspects, and the present invention is not limited thereto. It is understood that countless variations that are not illustrated can be envisaged without departing from the scope of the present invention.

  DESCRIPTION OF SYMBOLS 1 Coordinator, 2 Host, 3 Coordinator control part, 4 Coordinator communication part, 5, 13 Antenna, 6 Radio channel determination part, 7 Broadcast signal generation part, 8 Connection processing part, 9 Ground communication part, 10 Terrestrial external apparatus, 11 Host Control unit, 12 host communication unit, 14 wireless channel switching unit, 15 storage unit, 16 identifier determination unit, 17 response processing unit, 18 on-vehicle communication unit, 19 on-vehicle external device, P1-P4 platform, R1-R3 train, G1, G2 Home door, E1-E3 Train door, D1-D4 Fixed position stop sensor.

Claims (17)

A handset whose first identifier is set in advance;
A base unit that establishes a wireless communication network using a predetermined wireless channel and wirelessly communicates with the slave unit wirelessly connected to the wireless communication network;
With
The base unit is
Transmitting a notification signal including the second identifier;
The slave is
Switch the radio channel to receive the notification signal;
When the set first identifier is equal to the second identifier included in the notification signal, a response signal for wireless connection to the wireless communication network is transmitted to the parent device that is the transmission source of the notification signal To
A wireless communication system. The wireless communication system is a specific low-power wireless system;
The wireless communication network is a PAN of the specific low power wireless system;
The base unit is a coordinator of the specific low power radio system,
The slave is a host of the specific low-power radio system;
The wireless communication system according to claim 1.   The wireless communication system according to claim 1, wherein the first identifier and the second identifier are identifiers for identifying the slave units. The base unit is
A base unit communication unit for performing wireless communication with the slave unit;
A radio channel determination unit that predetermines the radio channel used in the base unit communication unit;
A notification signal generation unit that generates the notification signal including the second identifier and transmits the notification signal through the base unit communication unit;
A connection processing unit that receives the response signal transmitted by the slave unit via the master unit communication unit;
With
The slave is
A storage unit for storing the first identifier;
A slave unit communication unit for performing wireless communication with the master unit;
A radio channel switching unit for switching the radio channel used in the slave unit communication unit;
An identifier determination unit that determines whether or not the second identifier included in the notification signal received via the slave unit communication unit is equal to the first identifier stored in the storage unit;
A response processing unit that transmits the response signal to the parent device that is the transmission source of the notification signal, via the child device communication unit, when the identifier determination unit determines that they are equal;
Comprising
The wireless communication system according to claim 1, wherein the wireless communication system is a wireless communication system. The notification signal is a beacon request signal;
The response signal is a beacon signal.
The wireless communication system according to claim 1, wherein the wireless communication system is a wireless communication system. The notification signal is a beacon signal;
The response signal is a PANA signal.
The wireless communication system according to claim 1, wherein the wireless communication system is a wireless communication system. The second identifier is included in a Sub-IE Content of IE Content that is a part of the MAC payload of the beacon request signal.
The wireless communication system according to claim 5. The second identifier is included in a Sub-IE Content of IE Content that is a part of the MAC payload of the beacon signal.
The wireless communication system according to claim 6. The base unit is installed with a fixed position,
The slave unit is installed in a moving body that moves or stops in the vicinity of the master unit,
A first external device communicating with the master unit;
A second external device communicating with the slave unit;
Based on conditions desired by the first external device, interlocking means for operating the first external device and the second external device via the wireless communication between the parent device and the slave device;
Further comprising
The wireless communication system according to claim 1, wherein the wireless communication system is a wireless communication system. A plurality of the slave units are installed on the mobile body,
A plurality of the master units are installed corresponding to the slave units of the mobile body,
According to the position of the slave unit installed in the mobile body, the master unit and the slave unit that perform wireless communication are selected.
The wireless communication system according to claim 9. The master unit is installed on a station platform,
The slave is installed on a train entering the platform,
The first external device has state grasping means for grasping an operation state of the train,
The interlocking means is
Based on the state grasped by the state grasping means of the first external device, the platform and the train door are controlled in conjunction with each other via the wireless communication.
The wireless communication system according to claim 9. The slave is
It further has channel grasping means for grasping in advance the wireless channel of the parent device for wireless communication,
When receiving the notification signal, preferentially switch to the radio channel grasped by the channel grasping means;
The wireless communication system according to claim 1, wherein the wireless communication system is a wireless communication system. A base unit that constructs a wireless communication network of a wireless communication system and wirelessly communicates with a slave unit that is wirelessly connected to the wireless communication network,
A base unit communication unit for performing wireless communication with the slave unit;
A radio channel determination unit that predetermines a radio channel to be used in the base unit communication unit;
A notification signal generating unit that generates a notification signal including an identifier and transmits the notification signal via the base unit communication unit;
A master unit characterized by comprising.   14. The master unit according to claim 13, wherein the identifier is an identifier for identifying the slave unit. A wireless device wirelessly connected to a wireless communication network of a wireless communication system and wirelessly communicating with a parent device that has constructed the wireless communication network,
A storage unit for storing a first identifier set in advance;
A slave unit communication unit for performing wireless communication with the master unit;
A radio channel switching unit that switches a radio channel used in the slave unit communication unit;
An identifier determination unit that determines whether the second identifier included in the notification signal from the parent device received via the slave unit communication unit is equal to the first identifier stored in the storage unit;
Response processing for transmitting a response signal for performing wireless connection to the wireless communication network to the parent device that is the transmission source of the notification signal via the child device communication unit when the identifier determination units are determined to be equal And
It is provided with the cordless handset.   The slave unit according to claim 15, wherein the first identifier and the second identifier are identifiers for identifying the slave units. A network construction process in which the master unit constructs a wireless communication network using a predetermined wireless channel;
A notification signal transmission step in which the parent device transmits a notification signal including a second identifier;
An identifier setting step for presetting the first identifier in the slave unit;
A notification signal receiving step in which the slave unit receives the notification signal by switching the wireless channel;
An identifier determination step for determining that the slave sets the set first identifier and the second identifier included in the received notification signal;
When it is determined in the identifier determining step that the first identifier and the second identifier are equal, the slave unit establishes a wireless connection to the wireless communication network with respect to the master unit that is the transmission source of the notification signal. A response signal transmission step of transmitting a response signal to be performed;
A wireless connection method comprising:

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