JP6767044B2 - Communication device - Google Patents

Description

The present invention relates to a communication device that constitutes a network with a mesh structure.

In a network having a mesh structure, each device may form a hierarchy with the root device at the apex. In such a form, each device has a parent device one level higher, and a parent-child relationship is established by exchanging control signals between the corresponding devices. The information to be reached to the root device is packet-transmitted from each device while relaying the parent device in sequence (= multi-hop).

On the other hand, in network communication with a mesh structure, the communication partners at the upper and lower levels of the hierarchy are determined based on the predetermined communication quality, communication cost, connection quality, route cost (connection success rate, received power, SNR), etc. The network is completed by confirming). Once the communication partner is confirmed, stable communication is possible by continuing to use the confirmed route unless an error occurs.

By the way, when the communication path is determined by the route cost or the like, the communication path converges to the optimum solution, resulting in a substantially tree structure. In a tree-structured network, the more communication devices are connected below the self, the more communication traffic that passes through the self and flows to the upper level. In other words, there are more opportunities to relay communication traffic that is not addressed to you. In addition, although there are originally multiple routes that can be communicated, they are fixed, and as a whole network, there is a difference in power consumption between communication devices that frequently generate communication traffic and communication devices that do not. It ends up. This is because, especially in a form in which a communication device is driven by a battery or the like, only the power consumption of a specific communication device increases, which causes a network disconnection due to a decrease in the remaining battery level of the communication device, and improves the communication efficiency of the entire network. There is a risk of lowering it.

Japanese Unexamined Patent Publication No. 2013-191358

As described above, the conventional communication device has a problem that the power consumption differs between the communication devices when the network having a mesh structure is configured. The present invention has been made to solve such a problem, and an object of the present invention is to provide a communication device capable of equalizing power consumption between communication devices constituting a network.

In order to solve the above-mentioned problems, the communication device of the embodiment is a communication device in a network having a hierarchical structure with the root device as the apex, and has its own identifier and self-hierarchical information indicating its own hierarchy in the hierarchical structure. The hierarchical storage unit that stores the data, the identifier of the adjacent device, the adjacent hierarchical information indicating the hierarchy of the adjacent device in the hierarchical structure, the communication quality information between the adjacent devices, and the count information indicating the number of routings to the adjacent device. When a routing event occurs for the adjacent device storage unit that stores the adjacent device information including a plurality of each and the device located higher than itself in the hierarchical structure, the adjacent hierarchical information and communication of each adjacent device included in the adjacent device information. A candidate extraction unit that extracts candidate devices as routing destination candidates from adjacent devices based on quality information, and a routing destination device is selected based on count information corresponding to each candidate device included in the adjacent device information. It includes a device selection unit and an update unit that updates the count information corresponding to the selected device in the adjacent device information.

According to the present invention, it is possible to provide a communication device capable of making power consumption uniform between communication devices constituting a network.

It is a block diagram which shows the structure of the communication apparatus which concerns on embodiment. It is a figure which shows the example of the adjacent device information of the communication device which concerns on embodiment. It is a flowchart which shows the autonomous network construction operation by the communication device which concerns on embodiment. It is a figure explaining the autonomous network construction by the communication device which concerns on embodiment. It is a figure which shows the example of the network configuration by the communication device which concerns on embodiment. It is a flowchart which shows the routing operation in the communication apparatus which concerns on embodiment. It is a figure which shows the state of the routing operation by the communication device which concerns on embodiment.

Hereinafter, the communication device according to the embodiment will be described in detail with reference to the drawings. As shown in FIG. 1, the communication device 1 of the embodiment constitutes a network NW having a mesh structure, and is directly or indirectly with an upper parent device P, a lower child device C, and a sibling device S in the same layer as itself. Is connected. The communication device 1 includes a transmission / reception unit 10 to which the antenna 15 is connected, a routing setting unit 20, a layer setting unit 30, a layer storage unit 35, an adjacent device registration unit 40, an adjacent device storage unit 45, and a condition determination unit 50. .. The parent device P, the sibling device S, and the child device C each have the same configuration as the communication device 1.

The transmission / reception unit 10 is a wireless interface that transmits and receives radio waves in the communication device of the embodiment. The transmission / reception unit 10 has not only the routing function described below, but also a function of transmitting / receiving specific data.

The routing setting unit 20 is an arithmetic block that executes a routing process in the network NW. The layer setting unit 30 is an arithmetic block that determines and updates the layer of the communication device 1 in the network NW. The hierarchical storage unit 35 stores its own identifier and the hierarchy in its own network NW. In the following description, the “hierarchy” is represented as a numerical value in which the communication device R located at the top of the hierarchical structure is set to “0” and the value increases by 1 as it goes down. The value of this layer can be defined as the value obtained by adding 1 to the layer of the adjacent device having the lowest route cost among all the adjacent devices.

The adjacent device registration unit 40 is an arithmetic block that sets and updates the parent device P that is one level higher in the network NW, the child device C that is one level lower, and the sibling device S that is on the same level as the adjacent device information. The adjacent device storage unit 45 stores the adjacent device information set and updated by the adjacent device registration unit 40.

FIG. 2 is an example of the adjacent device information stored in the adjacent device storage unit 45. As shown in FIG. 2, in the communication device of the embodiment, the address of each adjacent device, the hierarchy in the network NW of each adjacent device, the communication quality corresponding to each adjacent device, and each of the adjacent devices are set as the adjacent device information. A count value indicating the number of times of routing is associated.

Here, assuming that the hierarchy of the communication device 1 is "2", the communication device of the address R (referred to as the device R; the same applies hereinafter) has a hierarchy of "0", which is higher and higher than itself. It can be seen that it is a router device that is the top of the network NW as well as its own parent device. Similarly, since the device B, the device C, and the device G have a hierarchy of "1" and are higher than the self, they are their own parent devices. Since the device M has a hierarchy of "2" which is the same as that of the self, the sibling device, the device I, and the device J are child devices lower than the self because the hierarchy is "3".

The communication quality in the adjacent device information is the communication quality in communication with the corresponding device, and is also called LQT (Link Quality Threshold). LQT is a numerical value indicating the link quality, and the smaller the numerical value, the better the quality. For example, if the LQT for which the link is set is set to 4, routing is performed with a device having an LQT of 4 or less as a communication partner.

The count value in the adjacent device information is numerical information indicating how many times the routing to the corresponding device has been performed. In the example shown in FIG. 2, the communication device 1 uses a natural number as the count value, and the routing settings are set 101 times for the device R, 100 times for the device B, and 99 times for the device C. It is shown that.

The condition determination unit 50 is a calculation block for determining a partner device to be routed by the communication device 1. The condition determination unit 50 determines the routing partner device by using the hierarchy of the adjacent device information, the communication quality, and the count value.

Subsequently, the network construction operation of the communication device 1 of the embodiment will be described with reference to FIGS. 1 to 4. The network NW in the embodiment has a hierarchical structure with the router device R at the top of the hierarchy as the apex. Therefore, the network construction is started by the device R broadcasting the halo packet. Hereinafter, the communication device 1 of the embodiment will be described as being the device D in FIG.

As shown in FIG. 3, the transmission / reception unit 10 receives a halo packet broadcast-transmitted from the higher-level device C (step 100, hereinafter referred to as “S100”).

The routing setting unit 20 extracts the identifier and hierarchy information of the other party from the received packet. Here, since the layer of the communication device 1 is not set in the initial state (No in S105), the layer setting unit 30 sets the value obtained by adding 1 to the layer information of the other party taken out by the routing setting unit 20. It is set as the hierarchy of, and is stored in the hierarchy storage unit 35 (S110).

Further, since the received packet is transmitted by at least a device higher than itself, the adjacency device registration unit 40 sets the other device of the identifier taken out by the routing setting unit 20 as the parent device, and sets the adjacency device storage unit. It is stored in 45 (S115). As a result, it is determined that the device C that has transmitted the received packet is the parent device of the device D.

If the self-layer has already been set (Yes in S105), and if the layer information taken out by the routing setting unit 20 and the self-layer stored in the layer storage unit 35 are the same (Yes in S120), the adjacent device is registered. The unit 40 sets the other device of the received identifier as a sibling device equivalent to itself, and stores it in the adjacent device storage unit 45 (S125). For example, considering the case where the HELLO packet from the device M shown in FIG. 4 is received, the layer of the other party is "2", so that it is the same as the device D. Therefore, the device M is a sibling device of the device D.

Further, when comparing the hierarchical information taken out by the routing setting unit 20 with its own hierarchy stored in the hierarchical storage unit 35 (S130), if the value of its own hierarchy is larger (Yes in S130), it is adjacent. The device registration unit 40 sets the other device of the received identifier as the parent device and stores it in the adjacent device storage unit 45 (S135). For example, considering the case where the HELLO packet from the device B shown in FIG. 4 is received, the layer of the other party is "1", so that it is higher than the communication device 1. Therefore, the device B is the parent device of the device D.

When the hierarchical information taken out by the routing setting unit 20 and the layer stored in the hierarchical storage unit 35 are compared (S130), if the own layer is smaller (No in S130), the adjacent device registration unit 40 The receiving partner is set as a child device and stored in the adjacent device storage unit 45 (S140). For example, considering the case where the HELLO packet from the device J shown in FIG. 4 is received, the layer of the other party is "3", so that it is lower than itself. Therefore, the device J is a child device of the device D.

When the hierarchy of the self and the remote device is determined, the routing setting unit 20 acquires the received communication quality information with the remote device (S145), and the adjacent device registration unit 40 uses the communication quality information as the address and hierarchy of the remote device. , Stored in the adjacent device storage unit in association with the communication quality (S150).

When the self-layer is determined, the transmission / reception unit 10 reads out the self-identifier and the layer from the layer storage unit 35 and transmits them as a hello packet (S155). Adjacent devices that have received the transmitted halo packet determine their respective layers according to the above procedure.

By sequentially performing these steps from the highest router device R, it is possible to establish a parent-child relationship and a sibling relationship with the devices within the communication range of each device, and it is possible to construct a network NW. it can.

It should be noted that the upper / lower relationship of the network NW does not have to be determined only by the autonomous operation described with reference to FIG. The upper / lower relationship may be set as appropriate based on the communication quality and the route cost.

Next, the routing operation in the communication device 1 of the embodiment will be described in detail.

In the mesh-structured network constructed as described above, various methods have been proposed for which parent device to perform routing, but in general, routing that realizes more efficient and economical communication is used. It has been adopted. However, when pursuing the route cost, the optimum solution for routing is converged into one, so that the communication route is converged into one even though there are multiple options.

FIG. 5 is an example of a network having a mesh structure, and has five layers from “0” (router device R) to “4” (device N). Taking device D as an example, it is connected to parent devices B, C and G, sibling devices M, and child devices I and J, and is in a state of being able to communicate with each other. Further, in the example shown in FIG. 5, a communication path is set directly from the device D to the router device R as well. In such a state, if routing is performed on the condition that the route cost is prioritized and the minimum number of layers and a predetermined communication quality (for example, LQT is 4 or less) are satisfied, the route converges to the route indicated by the thick line. That is, the packet from the device D is directly routed to the device R without passing through the parent devices B and C.

Since the device D has the devices I and J at the lower level, the communication traffic passing through the device D must also be transmitted to the higher device. On the other hand, the device B and the device C consume less power than the device D because there is no communication route sent from the lower level other than the own communication traffic (the routing indicated by the thick line does not exist). It is in a state of being finished. Then, as a whole network shown in FIG. 5, there is a high possibility that the battery of a specific device (device having a lot of communication traffic) will be consumed quickly and will be disconnected. In the communication device 1 of the embodiment, the routing destination is sequentially changed from the adjacent devices satisfying the communication quality to equalize the power consumption of each device in the network, thereby prolonging the operating time of the entire network. Is possible.

Specifically, the communication device 1 of the embodiment manages the routing destination device, the corresponding communication quality, and the number of routings (count value) in association with each other as the adjacent device information to be stored in the adjacent device storage unit 45. Figure 2). Then, the routing setting unit 20 determines the routing destination so that the number of routings becomes uniform.

Hereinafter, the routing operation of the communication device 1 of the embodiment will be described with reference to FIGS. 6 and 7. In the following description, the communication device 1 is assumed to be the device D on the network shown in FIG. 7. In the first stage, the device D sets the device R as the routing destination (thick line in FIG. 7).

When a routing event occurs (S300), such as when a communication traffic occurs in the communication device 1, the condition determination unit 50 reads the adjacent device information from the adjacent device storage unit 45 and extracts a device that is a candidate for the routing destination. That is, a device whose hierarchy is higher than itself and whose predetermined communication quality is satisfied is extracted. In the examples shown in FIGS. 2 and 7, device R (address R), device B (same B), device C (same C), and device G (same G) are applicable. That is, a device having a hierarchy of 1 or 0 and a communication quality of 4 or less is extracted.

Next, the condition determination unit 50 selects the device having the smallest count value among the four selected devices (S305). In the example shown in FIG. 2, the device C is applicable.

When the device C is selected as the routing candidate, the routing setting unit 20 sets the device C as the routing destination (S310). As a result, the routing destination of the communication traffic is changed from the device R to the device C.

When the routing destination is determined to be the device C, the adjacent device registration unit 40 adds "1" to the count value of the device C among the adjacent device information stored in the adjacent device storage unit 45 (S315). That is, "1" is added to "99" in FIG.

When the addition process of the count value is completed, the adjacent device registration unit 40 stores the updated adjacent device information in the adjacent device storage unit 45 (S320). When the count value reaches the upper limit (for example, counting from 0 and 255), if the count value is reset and counted from "0" again, the same operation can be continued.

As a result of such an operation, the device D in FIG. 7 selects not only the device R but also the device B, the device C, and the device G as the routing destination (broken line in FIG. 7). By performing this operation in all the devices constituting the network, the routing destinations can be evenly distributed, and the power consumption of each device can be made uniform.

As described above, since the communication device 1 of the embodiment manages the information indicating the address, hierarchy, communication quality, and number of routings of the adjacent device in association with each other, the hierarchy and communication quality are not fixed without fixing the routing destination device. All devices that meet the requirements of the routing destination, such as, can be set as the routing destination evenly.

1 ... Communication device, 10 ... Transmission / reception unit, 20 ... Routing setting unit, 30 ... Hierarchical setting unit, 35 ... Hierarchical storage unit, 40 ... Adjacent device registration unit, 45 ... Adjacent device storage unit, 50 ... Condition determination unit, P ... Parent device, S ... brother device, C ... child device, NW ... network.

Claims (2)

A battery-powered communication device in a hierarchical network with the root device at the top.
A hierarchical storage unit that stores an identifier of itself and self-hierarchical information indicating its own hierarchy in the hierarchical structure, and
Adjacent including a plurality of identifiers of adjacent adjacent devices, adjacent hierarchical information indicating the hierarchy of the adjacent device in the hierarchical structure, communication quality information with the adjacent device, and count information indicating the number of routings to the adjacent device. Adjacent device storage unit that stores device information and
When a routing event occurs for a device located higher than itself in the hierarchical structure, the adjacent device of the adjacent device is based on the adjacent hierarchical information and the communication quality information of each of the adjacent devices included in the adjacent device information. A candidate extraction unit that extracts candidate devices that are routing destination candidates from the inside,
A device selection unit that selects a device as a routing destination based on the count information corresponding to each of the candidate devices included in the adjacent device information.
It includes an update unit that updates the count information corresponding to the selected device in the adjacent device information .
The adjacent device information includes a natural number value as the count information.
The update unit adds 1 to the count information each time the device selection unit selects the selected device as the routing destination, and resets the count value when the count information reaches the upper limit.
The device selection unit selects the device having the smallest value of the corresponding count information among the candidate devices.
A communication device characterized by . The claim is characterized in that the candidate extraction unit extracts a device whose hierarchy is higher than itself among the adjacent devices and whose communication quality information corresponds to a predetermined criterion is extracted as the candidate device. 1. The communication device according to 1.

Images