JP6351399B2 - Wireless communication apparatus and route construction method - Google Patents

Description

  The present invention relates to a wireless communication apparatus and a route construction method.

  Conventionally, in a cluster tree that is one of the topologies of wireless networks, a wireless protocol communicates with other wireless stations by a routing protocol standard RPL (Routing Protocol for Low Power and Lossy Networks), and routes between the wireless stations. There is a method of building.

  In RPL, each wireless station receives a DIOG (DODAG (Destination Oriented Directed Acyclic Graph) Information Object) message broadcast from surrounding wireless stations, compares the information contained in the DIO message, and selects an uplink path. . Each wireless station can select a path with more stable received power in response to changes in the wireless environment. The new radio station selects an uplink path from the received DIO message. The new radio station transmits a DAO (DODAG Advertisement Object) message to the existing radio station that is the selected route, and when the new radio station receives the message, it establishes an uplink route. The existing radio station that has received the DAO message further transmits the DAO message to the radio station on the upstream path. By repeating this, a route from the new radio station to the parent radio station is completed.

  Even after obtaining the uplink route, when a new radio station receives a DIO message from another radio station, the new radio station has a smaller uplink value Rank value compared to the DIO message of the current uplink route radio station. Follow the procedure to change the route to the station. One of the features of RPL is that the route can be changed at any time due to changes in the wireless environment.

  A normal radio station can change to a more stable route by constantly receiving a DIO message. On the other hand, a radio station connected to an external device for battery operation and subjected to sleep control cannot receive a DIO message during sleep. The wireless station that receives the sleep control is woken up at the timing of the external device and is requested to transmit data, but communication with the upstream wireless station may fail due to changes in the wireless environment. Since the radio station that receives the sleep control continues to use the uplink path selected in the past, a stable path may not be secured in the changing radio environment, and data transmission may fail. In addition, battery-powered radio stations are also required to reduce the burden of battery consumption due to an increase in communication messages in order to suppress the burden of battery replacement. The RPL described above does not target a wireless station that performs a sleep operation, but targets a wireless station that acts as a relay having a routing function.

  As a method of reducing the burden of battery consumption while ensuring a stable route in a changing wireless environment, for example, in Patent Document 1 below, the sensor node of a sensor network is in a dormant state during normal operation and is controlled by timer control. A technique for performing sensing and routing by transitioning to an activated state is disclosed.

JP 2010-050909 A

  However, according to the above-described conventional technology, the sensor node itself corresponding to the wireless station controls the wake-up and sleep with the initiative of the sensing operation timing corresponding to the user data message transmission. There is a problem that the control method in the case of a wireless station that receives a sleep control and data transmission request by an external device is not disclosed and cannot be applied.

  The present invention has been made in view of the above, and an object of the present invention is to obtain a wireless communication device and a route construction method capable of entering a wireless network system and periodically updating a route while receiving sleep control by an external device. To do.

To solve the above problems and achieve the object, the present invention includes a route construction control means for controlling the construction of the path of the other wireless communication device constituting the non-linear network system, the update time of the route comprising a route expiration monitoring means control to, the, the route construction control means waking from the sleep state to the update time that is set in the previous SL route expiration monitoring means, the route to the other wireless communication device Send a construction start message, accept a response message from the other wireless communication device to the route construction start message for a specified period, select an uplink wireless communication device based on information included in the response message, and select There rows route update by sending an uplink path notification message to the wireless communication device of uplink routes, repeatedly performing the route update, characterized in that.

  Advantageous Effects of Invention According to the present invention, it is possible to enter a wireless network system and periodically update a route while receiving sleep control from an external device.

FIG. 1 is a diagram illustrating a state where a constantly activated radio station newly enters. FIG. 2 is a sequence diagram illustrating a flow of messages between wireless stations until the path construction is completed in a newly activated constantly activated wireless station. FIG. 3 is a diagram illustrating a state in which the constantly activated radio station changes the route. FIG. 4 is a sequence diagram showing the flow of messages between wireless stations until the path change is completed in the constantly activated radio station that changes the path. FIG. 5 is a diagram illustrating a configuration example of a sleep operation radio station. FIG. 6 is a diagram illustrating a state in which a sleep operation radio station newly enters. FIG. 7 is a sequence diagram showing the flow of messages between wireless stations until the path construction is completed in the sleep operation wireless station that has newly entered. FIG. 8 is a diagram illustrating a state in which the sleep operating radio station changes the route. FIG. 9 is a sequence diagram illustrating the flow of messages between wireless stations until the path change is completed in the sleep-operation wireless station that changes the path.

  Embodiments of a wireless communication apparatus and a route construction method according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
A configuration of the wireless network system will be described. In a wireless network system, when a route is constructed by RPL, a parent radio station is at the highest level, and one or more child radio stations are wirelessly connected thereunder, and one is further provided under each child radio station. Alternatively, a plurality of other child radio stations are wirelessly connected to form a tree-shaped multistage system. All the radio stations (parent radio station and child radio station) have a routing table, and in sending and receiving messages, each refers to the routing information in the routing table and is used to make the message reach the target radio station. The wireless station to be the relay transfer destination of is determined. Thereby, in the wireless network system, the parent wireless station can relay and transfer the message to the target child wireless station.

  On the other hand, battery-powered radio stations intended for installation away from power supply facilities are woken up when an external device needs to send and receive messages in order to reduce battery consumption, and sleep otherwise. It is done. Hereinafter, a radio station that is subjected to sleep control by an external device is referred to as a sleep operation radio station in order to distinguish it from a radio station that is always activated (referred to as a constantly activated radio station).

  Next, the operation from the start of the normally activated radio station to the completion of the route construction will be described with reference to FIGS. FIG. 1 shows a state where three child radio stations 1C, 1B, and 1D have already built a route under the parent radio station 2 to form a wireless network, and a child radio station 1A that is a constantly activated radio station newly enters the network. FIG. FIG. 2 is a sequence diagram showing the flow of messages between the radio stations until the path construction is completed in the child radio station 1A of the newly activated constantly activated radio station. Here, the child radio stations 1A to 1D are always activated radio stations.

  First, the slave radio station 1A broadcasts and transmits a DIS (DODAG Information Solicitation) message to the neighboring slave radio stations 1 (step S1).

  Here, the child radio station 1B that has received the DIS message in the vicinity transmits a DIO message (step S2). If the slave radio station 1A receives the DIO message first without transmitting the DIS message, it may not transmit the DIS message.

  The child radio station 1A that has received the DIO message from the child radio station 1B unicasts the DAO message to the child radio station 1B (step S3).

  When the child radio station 1A confirms that the DAO message has arrived at the child radio station 1B, the child radio station 1B determines the child radio station 1B as an uplink route, and registers the route information in its own routing table (step S4).

  When receiving the DAO message from the child radio station 1A, the child radio station 1B stores the information of the child radio station 1A in the DAO message and transmits it to the child radio station 1C (step S5). In association therewith, its own routing table is updated (step S6).

  Similarly, when receiving the DAO message from the child radio station 1B, the child radio station 1C stores the information of the child radio station 1A in the DAO message and transmits it to the parent radio station 2 (step S7). Updates its own routing table in relation to the station 1A (step S8).

  When receiving the DAO message from the child radio station 1C, the parent radio station 2 updates its own routing table in relation to the child radio station 1A (step S9). Through the procedure from Steps S1 to S7, the path from the slave radio station 1A to the master radio station 2 is completed, and the slave radio station 1A can join the radio network.

  Next, the operation in which the constantly activated radio station performs route update will be described with reference to FIGS. FIG. 3 shows a state in which four child radio stations 1C, 1B, 1D, and 1A have already been constructed with the parent radio station 2 to form a wireless network, and the child radio station 1A that is a constantly activated radio station changes its route. FIG. FIG. 4 is a sequence diagram showing the flow of messages between radio stations until the path change is completed in the child radio station 1A of the normally activated radio station that changes the path.

  Here, each wireless station stores a parameter of the effective period of the downlink route called Lifetime in the DAO message to be transmitted. The upstream radio station monitors Lifetime for each subordinate radio station. When the next DAO message cannot be received within the Lifetime period, the upstream radio station deletes the radio station information about the DAO message from the routing table.

  On the other hand, each radio station includes a value called Rank indicating the relative position from the parent radio station 2 in the DIO message to be transmitted. When receiving a DIO message from a plurality of radio stations, the downlink radio station compares the Rank values and selects a radio station having a small Rank value as an uplink route candidate. A radio station that has not received a DIO message from an uplink radio station for a certain period of time due to a change in the radio environment after the previous path construction or update, selects another radio station that has received the DIO message as an uplink path, Send a DAO message.

  When receiving the DIO message periodically transmitted from the child radio station 1B (step S10), the child radio station 1A unicasts a DAO message to the child radio station 1B as a response (step S11).

  When the slave radio station 1A receives the DIO message from the slave radio station 1D (step S12), the slave radio station 1B compares the Rank value of the slave radio station 1B with the Rank value of the slave radio station 1D. When the Rank value of the child radio station 1D is superior to the Rank value of the child radio station 1B, the child radio station 1A changes the uplink path from the child radio station 1B to the child radio station 1D. In this case, the child radio station 1A transmits a DAO message to the child radio station 1D (step S13).

  Although the child radio station 1A has been described, the other child radio stations 1 perform the same procedure as steps S10 to S13. Although explanation is omitted in FIG. 4, each child radio station 1 can maintain the route information in its routing table periodically by continuing the procedure from step S10 to S13. An appropriate route can be maintained.

  However, the operations in steps S1 to S13 are for a normally activated radio station that always operates without going to sleep, and not for a sleep-operating radio station. In particular, a child radio station that is put to sleep by an external device cannot perform the operations of steps S10 to S13 during sleep.

  Next, operations of path construction and path update by the sleep operation radio station according to the present embodiment will be described. First, the configuration of the sleep operating radio station will be described. FIG. 5 is a diagram illustrating a configuration example of a slave radio station 1A ′ that is a sleep operation radio station. The slave radio station 1A ′ includes an antenna 11, a radio processing unit 12, a signal processing unit 13, a route construction control unit 16 including an operation control unit 14 and a route construction unit 15, a routing table 17, and a route expiration date monitor. Unit 18.

  The antenna 11 transmits / receives various messages to / from other wireless stations.

  The radio processing unit 12 performs control to transmit the transmission signal passed from the signal processing unit 13 to another radio station via the antenna 11, and controls to pass the reception signal received via the antenna 11 to the signal processing unit 13. I do.

  The signal processing unit 13 performs signal processing such as modulation on an external input signal input from an external device (not shown) and passes the signal to the wireless processing unit 12 as a transmission signal. On the other hand, it performs signal processing such as demodulation and outputs it to an external device as an external output signal. Further, the signal processing unit 13 passes various messages to the wireless processing unit 12 according to an operation instruction from the operation control unit 14, and information such as an operation state based on the various messages passed from the wireless processing unit 12 to the operation control unit 14. Notice. Further, the signal processing unit 13 notifies the operation control unit 14 of information on the input frequency of an external input signal input from an external device as an operation state notification.

  The operation control unit 14 instructs the signal processing unit 13 to transmit various messages in response to a route request from the route building unit 15, and sends information such as a route based on the various messages passed from the signal processing unit 13 to the route building unit. 15 is notified. In addition, the operation control unit 14 notifies the path expiration date monitoring unit 18 of information on the input frequency of the external input signal notified from the signal processing unit 13 as an operation state notification.

  The path construction unit 15 performs control to transmit a DIS message as a path request, set a path from a path notification based on the DIO message received as a response, and transmit a DAO message. The route construction unit 15 inputs / outputs route information to / from the routing table 17, registers route information in the routing table 17 when a new route is set, and routes in the routing table 17 when a route is changed. Update information. Further, the route construction unit 15 notifies the route expiration date monitoring unit 18 of the route information related to the own station (child radio station 1A ′), and the downlink route expiration date specified by the route expiration date monitoring unit 18 ( Based on Lifetime), the DAO message is transmitted.

  The route construction control unit 16 includes an operation control unit 14 and a route construction unit 15 and is route construction control means for controlling construction of a route with another wireless communication device (child radio station 1) constituting the wireless network system. .

  The routing table 17 accepts registration and update of route information from the route construction unit 15 and holds route information about other wireless stations in the wireless network system.

  The route expiration date monitoring unit 18 sets the expiration date based on the route information from the route construction unit 15 and the operation state notification from the operation control unit 14, determines the wake-up time (wake-up alarm) based on the expiration date, and the route Route expiration date monitoring means for controlling the update timing of The route expiration date monitoring unit 18 designates the expiration date to the route construction unit 15 and sets the wake-up time for the route construction control unit 16 (the operation control unit 14 and the route construction unit 15).

  Next, the operation from the start of the sleep operation radio station to the completion of the route construction will be described with reference to FIGS. FIG. 6 shows a state where three child radio stations 1C, 1B, and 1D have already built a path under the parent radio station 2 to form a wireless network, and a child radio station 1A ′ that is a sleep operation radio station newly enters the network. FIG. FIG. 7 is a sequence diagram showing the flow of messages between radio stations until the path construction is completed in the slave radio station 1A ′ of the newly entered sleep operation radio station. Here, the slave radio station 1A ′ is a sleep operation radio station, and the slave radio stations 1B to 1D are always activated radio stations.

  First, the child radio station 1A ′ broadcasts a DIS message to the neighboring child radio stations 1 under the control of the path construction unit 15 (step S21). The slave radio station 1A ′ broadcasts a DIS message by the operation of the operation control unit 14, the signal processing unit 13, the radio processing unit 12, and the antenna 11 under the control of the route request from the route construction unit 15. For the sake of brevity, the control subject will be described, and the same applies to the following description.

  The neighboring child radio stations 1B and 1D that have received the DIS message broadcast the DIO message (step S22).

  Under the control of the path construction unit 15, the slave radio station 1A ′ collects the DIO messages from the one or more slave radio stations 1 transmitted in the above-described step S22 for a specified period (step S23).

  In the child radio station 1A ′, the path construction unit 15 selects the optimum uplink child radio station 1 from among the collected DIO messages, for example, reception power is sufficiently high, or the rank value of the DIO message is superior. Then, the sub radio station 1D is selected and a DAO message is transmitted to the sub radio station 1D (step S24).

  In the child radio station 1A ', the path construction unit 15 registers the child radio station 1D in the routing table 17 as an uplink path after completion of the DAO message transmission (step S25).

  When receiving the DAO message from the child radio station 1A ′, the child radio station 1D stores the information of the child radio station 1A ′ in the DAO message and transmits the information to the child radio station 1C (step S26). It updates its own routing table in relation to 1A ′ (step S27).

  When the child radio station 1C receives the DAO message from the child radio station 1D, the child radio station 1C stores the information of the child radio station 1A ′ in the DAO message and transmits it to the parent radio station 2 (step S28). The own routing table is updated in relation to '(step S29). Then, when receiving the DAO message from the child radio station 1C, the parent radio station 2 updates its own routing table in relation to the child radio station 1A ′ (step S30). Thereby, the route from the child radio station 1A ′ to the parent radio station 2 is completed, and the child radio station 1A ′ can participate in the wireless network.

  After the route is constructed, in the child radio station 1A ′, the route expiration date monitoring unit 18 sets the wake-up time before the expiration time of the uplink route Lifetime, and is autonomous depending on the wake-up time even in the state of being put to sleep by an external device. It is set in a state where it can be woken up (step S31).

  The operation in which the sleep operation radio station performs route update will be described with reference to FIGS. In FIG. 8, four child radio stations 1C, 1B, 1D, and 1A ′ have already built a route under the parent radio station 2 to form a wireless network, and the child radio station 1A ′ of the sleep operation radio station changes the route. It is a figure which shows the state to do. FIG. 9 is a sequence diagram showing the flow of messages between radio stations until the path change is completed in the slave radio station 1A ′ of the sleep operation radio station whose path is changed.

  In the child radio station 1A ′, the route construction control unit 16 autonomously wakes up when the wake-up time set by the route expiration date monitoring unit 18 is reached (step S31), and is controlled by the route construction unit 15 in the same manner as described above. A DIS message is broadcasted to the child radio station 1 (step S21).

  The neighboring child radio stations 1B and 1D that have received the DIS message broadcast the DIO message (step S22).

  The child radio station 1A ′ collects the DIO messages from the one or more child radio stations 1 transmitted in the above-described step S22 for a predetermined period under the control of the path construction unit 15 (step S23). The optimum slave radio station 1B is selected from the DIO messages thus transmitted, and a DAO message is transmitted to the slave radio station 1B (step S24 ').

  In the slave radio station 1A ′, the path construction unit 15 updates the routing table 17 with the slave radio station 1B as the uplink path after completing the DAO message transmission (step S25 ′).

  When receiving the DAO message from the child radio station 1A ′, the child radio station 1B stores the information of the child radio station 1A ′ in the DAO message and transmits the information to the child radio station 1C (step S26 ′). The own routing table 17 is updated in relation to the station 1A ′ (step S27 ′). The subsequent steps S28 to S31 are the same as those in FIG.

  The radio environment changes, and the child radio station 1A ′ that is the sleep operating radio station, like the child radio station 1A that is always activated radio station (step S12 in FIG. 4), from the neighboring child radio stations 1 The route cannot be updated according to the DIO message transmitted from time to time. Therefore, even when the slave radio station 1A ′ is under sleep control by an external device, the slave radio station 1A ′ periodically wakes itself up with the set wake-up time as the update time, and confirms the radio environment for a certain period (step) In step S23, the optimum uplink child radio station 1 is selected (steps S24 and S24 '), and this is repeated, whereby an optimum route can be obtained.

  As described above, according to the present embodiment, in the wireless network system constructed by the normally activated radio station that performs the path construction by RPL, the slave radio station 1A ′ that receives the sleep control by the external device Even in the sleep state by the sleep control, the wake-up time is set, the autonomous wake-up is periodically performed, and the route update with other child radio stations 1 is performed. As a result, the child radio station 1A ′ that receives the sleep control is periodically configured so that the communication path does not remain damaged due to changes in the radio environment, whenever an external device requests transmission of a user data message. It is possible to wake up autonomously and secure an optimum route, and to reduce the occurrence of a situation such as delay or data discard due to retransmission at the time of data transmission.

Embodiment 2. FIG.
The configuration, operation, and path construction procedure of the slave radio station 1A ′ according to the present embodiment are the same as those in the first embodiment. In the child radio station 1A ′, the path expiration date monitoring unit 18 adjusts the value of Lifetime, which is a parameter of the effective period of the downlink, based on the interval at which the transmission request of the user data message is generated by the external device.

  As described in the first embodiment, the route expiration date monitoring unit 18 uses the signal processing unit 13 and the operation control unit 14 as information on the input frequency of an external input signal input from an external device (not shown) as an operation state notification. Is getting.

  When the period of the user data message transmission request by the external device is long, the route expiration date monitoring unit 18 sets the Lifetime value to be longer than the value before the change, and instructs the route construction unit 15 to set the Lifetime when updating the route. Control is performed to transmit a DAO message reflecting the value change to the child radio station 1 on the upstream path. In addition, the route expiration date monitoring unit 18 also extends the wake-up time for the route construction control unit 16 according to the increase in the value of Lifetime.

  On the other hand, the route expiration date monitoring unit 18 sets the value of Lifetime to be shorter than the value before the change when the cycle of the user data message transmission request by the external device is short, and instructs the route construction unit 15 to update the route. Control is performed to transmit a DAO message reflecting the change of the value of Lifetime to the child radio station 1 on the upstream path. Also, the route expiration date monitoring unit 18 shortens the wake-up time for the route construction control unit 16 in accordance with the shortened value of Lifetime.

  Thereby, in the sub radio station 1A ′, it is possible to update the route at an appropriate period according to the communication frequency of the external device, and it is possible to suppress waste of the packet transmission / reception amount related to the route update. In addition, the child radio station 1A ′ can suppress battery consumption by suppressing an increase in the amount of packet transmission / reception.

  As described above, the wireless communication apparatus and the path construction method according to the present invention are useful for a wireless network, and are particularly suitable for a cluster tree type.

  1A, 1B, 1C, 1D Child radio station (always activated radio station), 1A 'child radio station (sleep operation radio station), 2 parent radio station, 11 antenna, 12 radio processing unit, 13 signal processing unit, 14 operation control Unit, 15 route construction unit, 16 route construction control unit, 17 routing table, 18 route expiration date monitoring unit.

Claims (5)

A route construction control means for controlling the construction of the path of the other wireless communication device constituting the non-linear network system,
Route expiration date monitoring means for controlling the update timing of the route;
With
The route construction control means, before Symbol pathway waking from the sleep state to the update time that is set in the expiration date monitoring means sends a route construction start message to the other wireless communication device, the other wireless communication A response message from the device to the route construction start message is received for a specified period, an uplink wireless communication device is selected based on information included in the response message, and an uplink route notification message is sent to the selected uplink wireless communication device gastric row routing update transmit, repeatedly performing the route update,
A wireless communication apparatus. Before Symbol path expiration monitoring means, the control of the update time of the route, the prior expiration of the validity period is information including the uplink path notification message, it sets the wake-up time for the route construction control means for waking up,
The wireless communication apparatus according to claim 1. The route expiration date monitoring means controls the cycle of the route update based on the frequency of data transmission requests received from an external device connected to the wireless communication device .
The wireless communication apparatus according to claim 1 or 2, characterized in that. And route construction starts transmitting the route construction start message to other wireless communication device constituting the non-linear network system,
A response accepting step of accepting a response message from the other wireless communication device to the route construction start message for a specified period;
A selection step of selecting an uplink wireless communication device based on information included in the response message, and transmitting an uplink notification message to the selected uplink wireless communication device;
A wake-up time setting step for setting a wake-up time to wake up before expiration of the validity period, which is information included in the uplink route notification message;
After sleep, and wake-up step of waking from the sleep state to the wake-up time,
Including
In the route update process after waking up, the operations from the route construction start step to the waking step are repeatedly performed.
A path construction method characterized by that. In the wake-up time setting step, the wake-up time is set based on the frequency of data transmission requests received from an external device connected to the wireless communication device .
The route construction method according to claim 4 , wherein:

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