JP2021077954A - Radio communication system and radio node - Google Patents

Abstract

To provide a radio communication technology that enables a three-dimensional radio route including a height direction to be easily constructed and enables the constructed radio route to be easily removed.SOLUTION: A radio communication system comprises: a core node located on a first horizontal plane; a radio repeater located on a second horizontal plane different from the first horizontal plane; and a radio repeater located on a third horizontal plane. The core node comprises a first antenna that has directionality towards the radio repeater. The radio repeater includes: a second antenna that has directionality towards the core node; a third antenna; and a processing unit that performs at least one of a process of processing a downlink radio signal received by the second antenna and transmitting the signal from the third antenna to a radio, and a process of processing an uplink radio signal received by the third antenna and transmitting the signal from the second antenna to the core node.SELECTED DRAWING: Figure 1A

Description

The present invention relates to wireless communication systems and wireless nodes.

In a cellular communication system, a base station that provides a wireless access line for a user device and a backbone network (sometimes referred to as a core network) may be connected by a wired backhaul (BH) network.

Japanese Unexamined Patent Publication No. 2005-143046 International Publication No. 2011/105371

On the other hand, as one form of realizing a new generation of mobile communication, wireless communication (for example, wireless communication) is performed between a plurality of wireless devices (for example, a base station or an access point) that provide a wireless communication area having a radius of several tens of meters. Systems or networks connected by (multi-hop) are being considered. The "wireless device" may be referred to as a "wireless node" or a "wireless communication device".

Here, for example, at a construction site such as a construction site, when it is desired to temporarily (or provisionally) introduce a wireless communication environment for field workers on different floors of a building, how can the wireless communication environment be easily introduced? There is room for construction and removal.

One of the non-limiting objects of the present invention is to provide a radio communication technique in which a three-dimensional radio route including the height direction can be easily constructed and can be easily removed.

The wireless communication system according to one aspect includes a core node located on a first horizontal plane, a wireless repeater located on a second horizontal plane different from the first horizontal plane, and a radio located on a third horizontal plane, and the core node. The radio repeater includes a first antenna having directionality toward the radio repeater, and the radio repeater receives the second antenna, the third antenna, and the second antenna having directionality toward the core node. A process of processing the downlink radio signal and transmitting it from the third antenna to the radio, and a process of processing the uplink radio signal received by the third antenna and transmitting it from the second antenna to the core node. A processing unit that performs at least one of the above and the above.

The radio node according to one aspect is a radio node located in the first horizontal plane, and has a first antenna having directivity toward a core node located in a second horizontal plane different from the first horizontal plane, a second antenna, and the like. The process of processing the downlink radio signal received by the first antenna and transmitting it from the second antenna to the radio, and the process of processing the uplink radio signal received by the second antenna and transmitting from the first antenna. It includes a process of transmitting to the core node and a processing unit that performs at least one of the processes.

According to a non-limiting aspect of the present invention, it is possible to provide a wireless communication technique in which a three-dimensional wireless route including the height direction can be easily constructed and can be easily removed.

It is a figure which shows the 1st state of the introduction example of the wireless communication system which concerns on one Embodiment. It is a figure which shows the 1st state of the introduction example of the wireless communication system which concerns on one Embodiment. It is a figure which shows the 2nd state of the introduction example of the wireless communication system which concerns on one Embodiment. It is a figure which shows the 2nd state of the introduction example of the wireless communication system which concerns on one Embodiment. It is a block diagram which shows the hardware configuration example of the node which concerns on one Embodiment. It is a figure which shows the example of the directivity of the antenna of the node which concerns on one Embodiment. It is a block diagram which shows the functional configuration example of the node which concerns on one Embodiment. It is a block diagram which shows the functional configuration example of the control part illustrated in FIG. It is a flowchart which shows an example of the link setup procedure between nodes which concerns on one Embodiment. It is a figure which shows the 1st example of the mesh link in the wireless communication system shown in FIG. 1A and FIG. 1B. It is a figure which shows the 2nd example of the mesh link in the wireless communication system shown in FIG. 1A and FIG. 1B. It is a flowchart which shows the operation example of the core node (CN) including the tree route control on the mesh link which concerns on one Embodiment. It is a flowchart which shows the operation example of the slave node (SN) including the tree route control on the mesh link which concerns on one Embodiment. It is a figure which shows the example of the tree path constructed in the 1st example of the mesh link shown in FIG. It is a figure which shows the example of the tree path constructed in the 2nd example of the mesh link shown in FIG.

Hereinafter, embodiments will be described with reference to the drawings as appropriate. Unless otherwise specified, the same elements are designated by the same reference numerals throughout the present specification. The matters described below, along with the accompanying drawings, are intended to illustrate exemplary embodiments and not to indicate a sole embodiment. For example, when the order of operations is indicated in the embodiment, the order of operations may be appropriately changed as long as there is no contradiction in the overall operation.

When a plurality of embodiments and / or variants are exemplified, some configurations, functions and / or operations in the embodiments and / or variants are, to the extent that there is no contradiction, in other embodiments. And / or may be included in the modifications and / or may be replaced by the corresponding configurations, functions and / or operations of other embodiments and / or variants.

Further, in the embodiment, an unnecessarily detailed description may be omitted. For example, publicly known or well-known technical matters in order to avoid unnecessarily redundant explanations and / or obscure technical matters or concepts and facilitate understanding by those skilled in the art. The detailed description of the above may be omitted. In addition, duplicate description of substantially the same configuration, function, and / or operation may be omitted.

The accompanying drawings and the following description are provided to aid in understanding the embodiments and are not intended to limit the subject matter described in the claims. In addition, the terms used in the following description may be appropriately read as other terms to aid the understanding of those skilled in the art.

<Knowledge that led to the present invention>

By making the BH network, which is one of the mobile communication infrastructures, wireless by wireless multi-hop, it is possible to eliminate the need for laying a wired cable and reduce the laying cost required for introducing a mobile communication system. Therefore, for example, when a mobile communication system is temporarily (or provisionally) introduced, it is effective to make the BH network wireless by wireless multi-hop.

Here, for example, at a construction site such as a construction site, when a wireless communication environment is temporarily (or provisionally) introduced for site workers on different floors of a building, the wireless communication environment depends on the progress of the construction. May change from moment to moment.

For example, in a situation where the foundation work and skeleton work of a building have been completed but the outer wall work has not yet been carried out, the radio nodes installed outside the building and the radio nodes installed inside the building are in line of sight. , LOS) environment or an environment close to the LOS environment. Therefore, it is easy to secure the expected wireless communication quality between the wireless nodes.

However, for example, as the outer wall construction progresses, the wireless nodes approach a non-line of sight (NLOS) environment, so that the wireless communication quality may deteriorate depending on the progress of the construction.

For example, at a building construction site, skeleton construction and outer wall construction may be performed in order for each floor of the building. The radio waves of the wireless nodes installed outside the building reach the wireless nodes installed on the floor where the outer wall construction inside the building has not been completed. On the other hand, the radio waves of the wireless nodes installed outside the building are likely to be shielded as the outer wall construction progresses, so that the wireless nodes installed in the layer where the outer wall construction is completed may not reach.

Therefore, the inventor of the present application can easily construct, for example, a three-dimensional wireless route including the height direction according to the progress of construction by applying the technology of the wireless BH network, and can easily remove it. It led to the development of wireless communication technology.

According to such wireless communication technology, for example, it contributes to the construction of a provisional wireless environment at a construction site. Hereinafter, non-limiting examples will be described.

In the present invention, as in the above-mentioned example, even if the radio wave propagation environment between the wireless nodes changes before and after the outer wall construction, it is possible to suppress the deterioration of the wireless communication quality due to the change.

<System configuration example>
1A and 1B are diagrams showing a first state of an introduction example of the wireless communication system according to the embodiment. 1A and 1B show an example in which the wireless communication system 1 is introduced at a building construction site. 1A and 1B show an X-axis, a Y-axis, and a Z-axis representing a three-dimensional space, respectively. The XY plane indicates a horizontal plane defined along the ground surface. The Z axis defines the height direction (vertical direction). Further, FIG. 1A is a view seen from the negative direction of the Y axis, and FIG. 1B is a view seen from the positive direction of the Z axis.

1A and 1B show a building under construction with four floors from the first floor to the fourth floor. The 4th floor of the building is the floor where the outer wall construction has not been completed, and the 1st to 3rd floors of the building are the floors where the outer wall construction has been completed. Further, FIGS. 1A and 1B show a tower crane for carrying building materials carried by a construction vehicle to a high place, a work range which is a place (accumulation place) for carrying building materials on the ground surface, and a position for avoiding the work range. The power supply box provided in is shown.

For example, when the power supply work for constructing an environment for supplying electric power to the electric equipment is not performed, the power supply box is installed in a corner of the construction site to supply electric power to the electric equipment used at the construction site. For example, the power supply box is installed near the construction work area at a position where it can be connected to the system power supply and does not obstruct the passage of construction vehicles (or construction machinery). Therefore, for example, the power supply box is installed at a predetermined distance from the construction area.

In order to tow the material by the tower crane, the material is accumulated on the ground surface within the working range of the crane directly under the tower crane. Since the tower crane sequentially pulls the accumulated materials to a high place, the working range of the tower crane is secured. Therefore, the power supply box is installed at the construction site, for example, avoiding the working range of the tower crane. The work range may be referred to as an "approach range" in which the construction vehicle enters.

At the construction site, at least one of the plurality of wireless nodes constituting the provisional BH network may be connected to, for example, a power supply box by wire to receive power from the power supply box.

In FIG. 1A, which is a side view of the XZ plane viewed from the side (negative direction of the Y axis), configurations of different positions in the Y axis direction are shown on the same surface. Further, in FIG. 1B, which is a bird's-eye view of the XY plane viewed from above (in the positive direction of the Z-axis), configurations of different positions in the Z-axis direction are shown on the same surface.

The state in which the outer wall construction on the first to third floors of the building has been completed and the outer wall construction on the fourth floor has not been completed, as shown in FIGS. 1A and 1B, may be described as "first state" below. is there.

The wireless communication system 1 shown in FIGS. 1A and 1B includes, for example, a plurality of wireless nodes (hereinafter, may be abbreviated as “nodes”) 3. In FIGS. 1A and 1B, as a non-limiting example, seven nodes 3 indicated by node numbers # 0 to # 6 are illustrated. The number of nodes 3 may be 2 or more and less than 7, or 8 or more.

A part of the nodes 3 among the plurality of nodes 3 may be connected to the backbone network 5 by wire. 1A and 1B illustrate an embodiment in which node # 0 is wiredly connected to the backbone network 5. For example, a LAN cable or an optical fiber cable may be applied to the wired connection.

Node # 0 wiredly connected to the backbone network 5 may be referred to as a "core node (CN)". Of the plurality of nodes 3 forming the BH network, each node 3 excluding CN # 0 may be referred to as a “slave node (SN)”.

In the wireless communication system 1 shown in FIGS. 1A and 1B, CN # 0 and SN # 1 are provided at specific positions.

For example, CN # 0 is provided in the vicinity of the power supply box on the ground surface (for example, within a range that can be connected by a power cable), and power is supplied from the power supply box. The XY plane on which CN # 0 is provided may be referred to as the "first horizontal plane". The position where CN # 0 is provided is not limited to the vicinity of the power supply box. CN # 0 may be provided at a position where a wired connection with the backbone network 5 is made.

SN # 1 is located in the vicinity of the side surface of the building facing CN # 0, which is located in the power supply box and is on the floor where the outer wall construction has not been completed in the building under construction. SN # 1 is provided, for example, at the swivel base of a tower crane. The swivel base may correspond to a portion that does not swivel, for example, when the tower crane pulls the material and swivels to bring the material into the building. The XY plane on which SN # 1 is provided may be referred to as a "second horizontal plane".

Tower cranes are used to tow materials and the like for pumping up the skeleton of a building under construction, and are typically placed above the top layer of the completed skeleton. Then, as the upper skeleton is completed, the tower crane is rearranged above the uppermost layer to be constructed next, and pulls the material used for the next uppermost skeleton.

As will be described later, since SN # 1 directly receives radio waves from CN # 0, it is desirable that there is no shield between CN # 0 and SN # 1. From this point of view, the swivel base of the tower crane is located at the uppermost layer of the building under construction regardless of the progress of the building work (for example, the height of the building). Therefore, the swivel base of the tower crane is suitable for mounting the SN # 1. Furthermore, the tower crane has a swivel structure that swivels the operating part, but when SN # 1 is placed in the swivel part, the reception strength of radio waves fluctuates according to the operation of the crane, and communication is unstable. There is a possibility that Therefore, it is more preferable to install the SN # 1 at a position facing CN # 0 of the swivel base than to install the SN # 1 at the swivel portion.

As an example, CN # 0 and SN # 1 are provided on the same XZ plane (see the dotted line L1 in FIG. 1B). In other words, in the present embodiment, as an example, the X-axis and the Y-axis are defined so that CN # 0 and SN # 1 are provided on the same XZ plane. Since the positions of the X-axis and the Y-axis are relative to the positions of CN # 0 and SN # 1, the positional relationship of these nodes is not limited to the shown positional relationship.

SN # 2 and SN # 3 will be located on the 4th floor of the building. SN # 4 to SN # 6 are provided on the 3rd to 1st floors of the building, respectively. Here, the XY plane on which SN # 2 is provided may be regarded as an example of the “third horizontal plane”. The third horizontal plane may be the same as the second horizontal plane described above. Further, for example, SN # 2 may be provided on an XZ plane different from CN # 0 and SN # 1 (see the dotted line L2 in FIG. 1B).

Each node 3 is an example of a wireless device capable of wireless communication. Therefore, each of the nodes 3 may be referred to as a "radio node 3". For wireless communication, a communication protocol compliant with (or based on) a wireless LAN (Local Area Network) related standard such as IEEE802.11b / g / a / n / ac / ad / ay may be applied.

Each node 3 forms an area where wireless communication is possible. The "area where wireless communication is possible" may be referred to as a "wireless communication area", a "wireless area", a "communication area", a "service area", a "coverage area", a "coverage area", or the like. The wireless communication area formed by the node 3 conforming to or based on the wireless LAN related standard may be regarded as corresponding to the "cell" which is the name in cellular communication. For example, the wireless communication area formed by each node 3 may be regarded as corresponding to a "femtocell" classified as a "small cell".

When each of the nodes 3 is located in the service area of the other node 3, it is possible to wirelessly communicate with the other node 3. The plurality of nodes 3 form, for example, a wireless backhaul (BH) network that wirelessly relays communication between the backbone network and the terminal device 7. The "wireless BH network" may be abbreviated as "wireless" and may be referred to as a "BH network".

The "BH network" may be referred to as a "relay network". Each node 3 that is an entity of the BH network may be referred to as a "relay node".

The path or section in which the wireless signal is transmitted in the BH network is mutually with the "wireless BH communication path", "wireless BH transmission path", "wireless BH line", "wireless BH connection", or "wireless BH channel". It may be read as. In these terms, "radio" may be omitted and "BH" may be read as "relay."

The wireless BH line may include at least one of a "downline" in the direction from the core node 3 to the slave node 3 and an "upline" in the direction from the slave node 3 to the core node 3. The "downlink" and "uplink" may be referred to as "downlink (DL)" and "uplink (UL)", respectively, following the names in cellular communication.

For example, when information is notified (notified) from the backbone network 5 to one or more slave nodes 3 via the core node 3, the wireless BH line may include a downlink line and may not include an uplink line. Further, when information is notified (notified) from one or more slave nodes 3 to the backbone network 5 via the core node 3 and the information is aggregated in the backbone network 5, the wireless BH line includes an uplink line. It does not have to include the backbone line. Even in the case of one-way information transmission between the uplink and the downlink, the configuration of the present embodiment includes them.

The flow of signals (downstream signals) in the "downstream" may be referred to as "downstream", and the flow of signals (upstream signals) in the "upstream" may be referred to as "upstream". Each of the "downlink signal" and the "uplink signal" may include a control signal and a data signal. The "control signal" may include a signal that does not correspond to the "data signal". Further, the "downlink signal" and "uplink signal" which are radio signals may be referred to as "downlink radio signal" and "uplink radio signal", respectively.

It should be noted that the "child node" may be regarded as corresponding to a node (downstream node) connected by a wireless link downstream of a certain node when focusing on the "downlink". When focusing on the downlink, a node connected to the upstream of a certain node by a wireless link may be referred to as a "parent node" or an "upstream node". When focusing on the "uplink", the relationship between the "child node" (downstream node) and the "parent node" (upstream node) is reversed.

On the other hand, for example, a section in which a wireless signal is transmitted between the terminal device 7 and the BH network may be referred to as a "wireless access line" or a "wireless access channel". In these terms, "radio" may be omitted.

The wireless access lines include a "downline" in the direction from the node 3 included in the BH network to the terminal device 7, and an "upline" in the direction from the terminal device 7 to the node 3 included in the BH network. At least one of the above may be included. Here, the node 3 may be a node for which a wireless connection with the terminal device 7 has been established.

For example, when information is notified (notified) from the backbone network 5 to the terminal device 7 via one or more nodes 3, the wireless BH line and the wireless access line include the downlink line and do not include the uplink line. It's okay. Further, when information is notified (notified) from the terminal device 7 to the backbone network 5 via one or more nodes 3 and the information is aggregated in the backbone network 5, the wireless BH line and the wireless access line go up. It may include a line and may not include a downlink. Even in the case of one-way information transmission between the uplink and the downlink, the configuration of the present embodiment includes them.

The BH network may have one or more tree structures (may be referred to as "tree topology") with one CN3 (# 0) as the root node.

For example, a tree-structured route (tree topology) in a BH network may be constructed based on, for example, a metric of a route from CN3 to a specific SN3 (hereinafter, may be abbreviated as “route metric”). As the route metric, an index (hereinafter referred to as "propagation quality index") indicating the quality or performance of radio wave propagation in the radio section from CN3 to a specific SN3 may be used.

Non-limiting examples of propagation quality indicators include received power or reception strength (for example, RSSI; Received Signal Strength Indicator) of a radio signal, radio wave propagation loss, propagation delay, and the like.

For example, by transmitting a signal (for example, a control signal) starting from CN3, the radio wave propagation loss of the radio section is transmitted to the receiving node 3 for each radio section between the transmitting node 3 and the receiving node 3 of the control signal. You can ask.

Then, each of the receiving nodes 3 includes the obtained information on the radio wave propagation loss in the control signal and transmits the information, so that the information on the cumulative radio wave propagation loss in the radio section in which the control signal is propagated (in other words, cumulative). Value) can be transmitted between nodes 3.

For example, each node 3 calculates a route metric based on the cumulative radio wave propagation loss for each upstream node candidate that is a source of the control signal, and the route metric indicates, for example, the minimum among the upstream node candidates. Select one node 3. As a result, a tree-structured route that minimizes radio wave propagation loss is constructed.

In the examples of FIGS. 1A and 1B, since SN # 2 and CN # 0 are in a line-of-sight environment (LOS environment), they have a positional relationship in which a wireless BH line can be constructed. In this way, when SN # 2 and CN # 0 are in the positional relationship shown in FIGS. 1A and 1B, SN # 2 and CN # 0 can communicate directly with each other, or via SN # 1. It is also possible to communicate with. In the present embodiment, the direct communication between SN # 2 and CN # 0 and the communication via SN # 1 are compared according to the radio wave condition at the time of communication, and a route with good radio wave condition is selected. To do. The route selection will be described later.

Here, for example, when the outer wall construction is completed on the 4th floor where SN # 2 is provided, SN # 2 and CN # 0 become a non-line-of-sight environment (NLOS environment).

The state in which the outer wall construction on the fourth floor of the building is completed, as shown in FIGS. 2A and 2B, may be described as "second state" below.

2A and 2B are diagrams showing a second state of the introduction example of the wireless communication system according to the embodiment. 2A and 2B show an example in which the wireless communication system 1 is introduced at the construction site of a building, similarly to FIGS. 1A and 1B. In addition, in FIGS. 2A and 2B, the outer wall construction on the 4th floor, which was incomplete in FIGS. 1A and 1B, has been completed, and the floor (5th floor) on which the outer wall construction has not been completed is one floor above the 4th floor. Is provided. Further, in FIGS. 2A and 2B, SN # 7 is provided on the fifth floor. Further, FIGS. 2A and 2B show a state in which the tower crane extends in the height direction (Z-axis direction) as compared with FIGS. 1A and 1B.

As shown in FIGS. 2A and 2B, when the outer wall construction is completed on the 4th floor where SN # 2 is provided, SN # 2 and CN # 0 become a non-line-of-sight environment (NLOS environment), so that the wireless BH It is no longer possible to build a line directly. Therefore, the constructed wireless BH line is likely to be disconnected.

In the present embodiment, in order to avoid disconnection of the constructed wireless BH line, a system design is performed in which the wireless BH line between SN # 1 and CN # 0 is preferentially constructed.

For example, in a wireless BH line, radio wave propagation loss between SN # 1 and CN # 0 is different from that of SN # 1 (for example, SN # 2 and SN # 7) and radio wave propagation between CN # 0. It has a configuration that keeps the state lower than the loss.

For example, the antenna of CN # 0 has directivity toward SN # 1, and the antenna of SN # 1 has directivity toward CN # 0.

The antenna having directivity may be a single flat antenna or an antenna whose directivity is controlled by a plurality of antenna arrays. The directivity of the antenna may be adjusted manually or automatically. For example, the directivity of the antenna may be adjusted by mechanically adjusting the orientation of the antenna, or the directivity may be adjusted by signal processing of signals transmitted and received by the antenna.

In the example of FIG. 1A, the antenna of CN # 0 is directed in the direction in which SN # 1 is provided (for example, _{the direction of θ 1 with} respect to the positive direction of the X axis) in the XZ plane. Further, among the antennas of SN # 1, the antenna that wirelessly communicates with the node (CN # 0) on the upstream side is in the direction in which CN # 0 is provided (for example, the negative direction of the X axis) in the XZ plane. Directivity is directed to the reference (direction of θ _1).

The angle defined in the XZ plane may be referred to as an "elevation angle" or a "depression angle". Further, the angle defined in the XY plane may be referred to as an "azimuth angle".

Antennas commonly used to build BH networks are designed to radiate radio waves in a horizontal plane to connect the nodes 3 to each other in a mesh. On the other hand, as in the present embodiment, in the radio wave radiation in the height direction (Z-axis direction in the figure) such that the CN # 0 installed on the ground surface and the uppermost layer SN # 1 are wirelessly connected. , Gives strong directivity to radio waves radiated by an antenna array that can control directivity. For example, by directing the directivity in _{the direction of θ 1} , the wireless communication environment between CN # 0 and SN # 1 can be optimized.

Further, in the example of FIG. 1A, the antenna that wirelessly communicates with the downstream node (SN # 2) among the antennas of SN # 1 is in the direction in which SN # 2 is provided (for example, in the XY plane). Directivity is directed in the direction _{of θ 2 with} respect to the positive direction of the X-axis.

An antenna that does not have directivity (for example, an omnidirectional antenna) emits radio waves that are weaker than the horizontal plane but have a strength that can withstand practical use if the elevation angle (or depression angle) from the horizontal plane is in the range of about 20 to 30 degrees. It can be radiated. Therefore, good communication may be ensured while the angle (elevation angle) between SN # 1 and SN # 2 is 30 degrees or less. However, as described above, since the SN # 1 installed on the tower crane is rearranged (moved) to the uppermost layer as the construction progresses, the elevation angle between the SN # 1 and the SN # 2 is increased. It can exceed 30 degrees. In such a case, wireless communication between SN # 1 and SN # 2 with an antenna having no directivity becomes difficult. Therefore, it is preferable to give directivity to the radio wave between SN # 1 and SN # 2. For example, it is preferable that the antenna of SN # 1 has directivity in the elevation angle direction.

Instead of giving the antenna of SN # 1 directivity in the elevation angle direction, the antenna of SN # 2 may have directivity in the elevation angle direction. Alternatively, both the antennas of SN # 1 and SN # 2 may have directivity in the elevation angle direction.

Further, the antenna of the SN3 provided on each floor of the building may or may not have directivity. For example, when a plurality of SN3s are provided on each floor of a building, a wireless mesh may be constructed for each floor. In this case, a specific SN3 of each layer may be set as a node that is a starting point of the wireless mesh of the layer.

In the examples of FIGS. 1A and 1B, SN # 3 arranged in the same layer as SN # 2 may communicate with SN # 1 via SN # 2. That is, the route from SN # 3 to CN # 0 may take a route connecting SN # 3 to SN # 2 and SN # 1 to reach CN # 0. A directional antenna emits less radio waves to a range other than the directional range than a normal antenna. Therefore, for example, when SN # 2 is set to the node that is the starting point of the wireless mesh on the 4th floor, SN # 3 (and other SN3s existing on the 4th floor (not shown)) is a normal antenna having no directivity. Is more suitable for constructing a wireless mesh in this hierarchy. That is, in each layer under construction, a specific SN3 having a directivity of transmission / reception in the directivity direction of SN # 1 is arranged in the directivity range of SN # 1 and becomes a node serving as a starting point of the wireless mesh of each layer. May be set. Then, an SN3 having an antenna that radiates radio waves widely in a horizontal plane may be arranged in an area where a specific SN3 does not cover in each layer.

As described above, even with a normal antenna, communication can be ensured if it is about 30 degrees from the horizontal plane. Therefore, in the present invention, as in the present embodiment, the angle formed by the core node CN # 0 arranged on the ground surface and the SN # 2 which is a wireless repeater which is supposed to directly wirelessly communicate with CN # 0 ( It is preferably carried out when the direction of θ _{1) is 30 degrees or more.}

In this embodiment, in the communication between the slave nodes, the optimum route is selected according to the radio wave condition. Therefore, if there is no shield between SN # 1 and SN # 3 and the elevation angle (or depression angle) is not large, the route from SN # 1 to SN # 2 and SN # 3 (first). Route) and the radio wave condition of the route from SN # 1 to SN # 3 (second route) are compared, and if the second route has better radio wave condition than the first route, the first route is used. Two routes may be selected. When the second route is selected, it is possible to reduce the load on SN # 2.

In this embodiment, the method of installing (mounting) SN # 1 on the tower crane is not limited. For example, installing SN # 1 on a tower crane does not have to be completely fixed. For example, a method may be adopted in which a fixing member (not shown) is fixed to the base of the tower crane, and SN # 1 is detachably attached to the fixing member. For example, the fixing member is threaded and is fixed by bolts that penetrate the exterior of SN # 1. Since the tower crane is exposed to wind and rain during the construction period, it is desirable that the SN # 1 be firmly mounted in order to prevent the SN # 1 from coming off or changing the direction of the SN # 1. Is done. On the other hand, if the SN # 1 is completely fixed, when the tower crane is rearranged, a huge crane will be moved with the SN # 1 attached. In this case, in the moving work, a large load may be unintentionally applied to the SN # 2, and the precision instrument SN # 2 may be damaged. Further, when the antenna of SN # 2 has an array configuration, the mutual positional relationship of the antenna arrays may deviate from the desired mutual positional relationship. Therefore, it is preferable that the SN # 1 is attached to the tower crane in a detachable manner. Also, in order to prevent adverse effects on radio waves, it is better to avoid using strong magnets such as neodymium magnets.

Then, when the transition from the first state shown in FIGS. 1A and 1B to the second state shown in FIGS. 2A and 2B, the directivity of the antenna and the arrangement position of the node serving as the starting point of each layer are changed. May be adjusted.

For example, in the example of FIG. 2A, the antenna of CN # 0 is directed in the direction in which SN # 1 is provided (for example, _{the direction of θ 3 with} respect to the positive direction of the X axis) in the XZ plane. Be done. Further, among the antennas of SN # 1, the antenna that wirelessly communicates with the node (CN # 0) on the upstream side is in the direction in which CN # 0 is provided (for example, the negative direction of the X axis) in the XZ plane. Directivity is directed to the reference (direction of θ _3).

Further, in the example of FIG. 2A, the antenna that wirelessly communicates with the downstream node (SN # 7) among the antennas of SN # 1 is in the direction in which SN # 7 is provided (for example, in the XZ plane). Directivity is directed in the direction _{of θ 4 with} respect to the positive direction of the X-axis.

Further, the antenna of the node 3 is not limited to the directivity in the XY plane, and may have the directivity in the XY plane. In other words, the antenna of the node 3 may have directivity in both the XY plane and the XY plane, so-called three-dimensional directivity.

For example, in the example of FIG. 1B, the antenna that wirelessly communicates with the downstream node (SN # 2) among the antennas of SN # 1 is in the direction in which SN # 2 is provided (for example, in the XZ plane). directivity in phi ₁ direction) in the positive direction to the reference of the X-axis is directed. Then, when transitioning from the first state to the second state, the antenna that wirelessly communicates with the downstream node (SN # 7) among the antennas of SN # 1 is SN # in the XZ plane. 7 is a direction (e.g., phi ₂ direction relative to the positive direction of the X axis) which is provided directivity can be directed to.

As described above, since the antenna has directivity, the wireless BH line between SN # 1 and CN # 0 is preferentially constructed in order to avoid disconnection of the constructed wireless BH line.

<Configuration example of node 3>
(Hardware configuration example of node 3)
Next, a hardware configuration example of the node 3 will be described with reference to FIG. The configuration example illustrated in FIG. 3 may be common to CN3 and SN3. As shown in FIG. 3, the node 3 includes, for example, a processor 31, a memory 32, a storage 33, an input / output (I / O) device 34, a wireless IF 35 and 36, a wired IF 37, a wired IF 39, and a bus 38. Good.

In the hardware configuration example illustrated in FIG. 3, the hardware may be increased or decreased as appropriate. For example, addition or deletion of arbitrary hardware blocks, division, integration in any combination, addition or deletion of bus 38, and the like may be appropriately performed.

The processor 31, the memory 32, the storage 33, the input / output devices 34, the wireless IFs 35 and 36, and the wired IFs 37 and 39 can be connected to, for example, the bus 38 and communicate with each other. The number of buses 38 may be one or plural.

A plurality of processors 31 may be provided in the node 3. Further, the processing in the node 3 may be executed by one processor 31 or may be executed by a plurality of processors 31. In one or more processors 31, a plurality of processes may be executed simultaneously in parallel or sequentially, or may be executed by other methods. The processor 31 may be a single-core processor or a multi-core processor. The processor 31 may be mounted using one or more chips.

One or more functions possessed by the node 3 are typically realized by causing hardware such as a processor 31 and a memory 32 to load predetermined software. Note that "software" may be read interchangeably with other terms such as "program", "application", "engine", or "software module".

For example, the processor 31 reads and executes a program by controlling one or both of reading and writing of data stored in one or both of the memory 32 and the storage 33. The program may be provided to the node 3 by communication via a telecommunication line by, for example, at least one of the wireless IF35, the wireless IF36, and the wired IF37.

The program may be a program that causes the computer to execute all or part of the processing at the node 3. Depending on the execution of the program code included in the program, one or more functions of the node 3 are realized. All or part of the program code may be stored in memory 32 or storage 33, or may be described as part of an operating system (OS).

For example, the program may include program code that embodies the functional blocks described below in FIGS. 5 and 6. A program containing such a program code may be referred to as a "radio route control program" for convenience.

The processor 31 is an example of a processing unit, and for example, operates an OS to control the entire computer. The processor 31 may be configured by using a central processing unit (CPU) including an interface with a peripheral device, a control device, an arithmetic unit, a register, and the like.

Further, the processor 31 reads, for example, one or both of the program and the data from the storage 33 into the memory 32 and executes various processes.

The memory 32 is an example of a computer-readable recording medium, and may be configured by using at least one of, for example, a ROM, an EPROM, an EEPROM, a RAM, and an SSD. "ROM" is an abbreviation for "Read Only Memory", and "EPROM" is an abbreviation for "Erasable Programmable ROM". "EEPROM" is an abbreviation for "Electrically Erasable Programmable ROM", "RAM" is an abbreviation for "Random Access Memory", and "SSD" is an abbreviation for "Solid State Drive".

The memory 32 may be referred to as a register, cache, main memory, work memory, or main storage device.

The storage 33 is an example of a computer-readable recording medium, and is an optical disk such as a CD-ROM (Compact Disc ROM), a hard disk drive (HDD), a flexible disk, an optical magnetic disk (for example, a compact disk, a digital versatile disk, etc.). It may be configured using at least one Blu-ray® disc), smart card, flash memory (eg, card, stick, key drive), flexible disc, magnetic strip, and the like. The storage 33 may be referred to as an auxiliary storage device. The recording medium described above may be, for example, a database, server or other suitable medium including one or both of the memory 32 and the storage 33.

The input / output (I / O) device 34 is an example of an input device that receives a signal input from the outside of the node 3 and an output device that outputs a signal from the node 3 to the outside. The input device may optionally include one or more of a keyboard, mouse, microphone, switches, buttons, and sensors. Output devices may typically include one or more of a display, a speaker, and a light emitting device such as an LED (Light Emitting Diode).

As described above, in the present embodiment, the node 3 has a function as a simple PC having a processor 31, a memory 32, and the like. With such a configuration, a so-called edge computing environment is realized, and by storing some information in one of the nodes 3, SN # 1 via CN # 0 → external It is also possible to perform typical tasks without reading data over the Internet (eg, backbone network 5). In the case of this embodiment, since CN # 0 and SN # 1 which is a wireless repeater serve as a route for communication of almost all slave nodes 3 other than SN # 1, data that is always used, for example, man-hour management. It is also preferable to store the sheet and / or the work process manual or the like in any of the nodes 3. For example, by storing the data used in each layer in the node 3 which is the starting point of each layer arranged in each layer, it is possible to complete the data communication in the corresponding layer. From this point of view, the storage 33 mounted on the SN # 1 may have a larger capacity than the storage 33 of the node (SN # 2 in FIG. 1A) which is the starting point of each layer. Further, the storage 33 of the node 3 that is the starting point of each layer may have a larger capacity than the storage 33 of the slave node 3 (SN # 3 in FIG. 1A) that is connected to the node 3 that is the starting point.

Buttons may include, for example, a power button and / or a reset button. The power button is operated, for example, to start and shut down node 3. The reset (or reroute) button is operated, for example, to instruct an intentional reset and / or rebuild (or reroute) of the tree path.

The input / output device 34 may have a separate configuration for input and output. Further, the input / output device 34 may have an integrated configuration of input and output, such as a touch panel type display.

The wireless IF 35 typically transmits and receives radio signals on an access line to and from the terminal device 7. The radio IF35 may include, for example, one or more antennas 350, a baseband (BB) signal processing circuit, a MAC processing circuit, an upconverter, a downconverter, and an amplifier, which are not shown.

The BB signal processing circuit of the wireless IF35 includes, for example, a coding circuit and a modulation circuit for encoding and modulating a transmission signal, and a demodulation circuit and a decoding circuit for demodulating and decoding a received signal. It's okay.

The radio IF36 typically transmits and receives radio signals to and from other SN3s on a BH line. Like the wireless IF35, the wireless IF36 may include one or more antennas 360, a BB signal processing circuit (not shown), a MAC processing circuit, an upconverter, a downconverter, and an amplifier.

The BB signal processing circuit of the wireless IF36 includes, for example, a coding circuit and a modulation circuit for encoding and modulating a transmission signal, and a demodulation circuit and a decoding circuit for demodulating and decoding a received signal. It's okay.

In CN # 0 and SN # 1 illustrated in FIGS. 1A to 2B, the antenna 360 of the wireless IF36 has directivity. For example, the antenna 360 of the wireless IF36 may be an antenna array whose directivity can be controlled. Beamforming may be performed by an antenna array having a plurality of directional antennas.

By way of example, the wired IF 37 transmits and receives a wired signal to and from the backbone network 5 and / or the upstream node 3. Further, the wired IF 39 typically transmits and receives a wired signal to and from the terminal device 7 and / or the downstream node 3. For the wired IFs 37 and 39, for example, a network interface conforming to the Ethernet (registered trademark) standard may be used. The wired IFs 37 and 39 may be provided in at least CN3 and may not be provided in SN3 (in other words, they may be optional for SN3). However, when a part of the BH line is connected by wire, the wired IFs 37 and 39 may be used for the wired connection.

Node 3 may be configured to include hardware such as a microprocessor, DSP, ASIC, PLD, and FPGA. For example, the processor 31 may be implemented including at least one of these hardware. The hardware may realize a part or all of each functional block described later in FIGS. 5 and 6.

In addition, "DSP" is an abbreviation for "Digital Signal Processor", and "ASIC" is an abbreviation for "Application Specific Integrated Circuit". "PLD" is an abbreviation for "Programmable Logic Device", and "FPGA" is an abbreviation for "Field Programmable Gate Array".

(Example of antenna directivity of node 3)
Next, an example of the directivity of the antenna 360 of the radio IF36 of each node 3 between CN # 0 and SN # 1 shown in FIGS. 1A and 1B is shown.

FIG. 4 is a diagram showing an example of the directivity of the antenna of the node according to the embodiment. FIG. 4 shows an example of the directivity of CN # 0, SN # 1, SN # 2, and the antenna of each node in the wireless communication system 1 shown in FIGS. 1A and 1B.

The antenna 360 of CN # 0 has directivity toward SN # 1, which is a node 3 on the downstream side. The antenna 360-1 of the SN # 1 has directivity toward the node 3 on the upstream side, CN # 0. With this configuration, the line condition of the wireless link between CN # 0 and SN # 1 can be made better than the line condition of the wireless link between the SN different from SN # 1 and CN # 0.

Further, the antenna 360-2 possessed by SN # 1 may have directivity toward SN # 2, which is a node 3 on the downstream side. With this configuration, the line condition of the wireless link between SN # 1 and SN # 2 can be made better than the line condition of the wireless link between SN different from SN # 2 and SN # 1.

(Example of functional configuration of node 3)
Next, a functional configuration example of the node 3 will be described with reference to FIGS. 5 and 6. FIG. 5 is a block diagram showing a functional configuration example of the node 3 according to the embodiment, and FIG. 6 is a block diagram showing a functional configuration example of the control unit illustrated in FIG.

As shown in FIG. 5, when focusing on the functional configuration, the node 3 has a wireless communication unit 301 for a wireless access line, a wireless communication unit 302 for a wireless BH line, a wired communication unit 303, a control unit 304, and , The storage unit 305 may be provided.

The wireless communication unit 301 for the wireless access line is a functional block including the wireless IF 35 and the access line antenna 350 illustrated in FIG. The wireless communication unit 302 for the wireless BH line is a functional block including the wireless IF36 and the BH line antenna 360 illustrated in FIG.

The wired communication unit 303 is a functional block including the wired IFs 37 and 39 illustrated in FIG. Further, the storage unit 305 is a functional block including one or both of the memory 32 and the storage 33 illustrated in FIG.

The wireless communication unit 301 is, for example, a transmission processing unit that transmits a control signal and / or a data signal addressed to the terminal device 7, and a reception processing unit that receives a control signal and / or a data signal transmitted by the terminal device 7. It may have at least one.

In other words, the wireless communication unit 301, which is an example of the processing unit, has at least one of processing of the downlink radio signal transmitted from the antenna 350 to the terminal device 7 and processing of the uplink radio signal received by the antenna 350. May be done.

The wireless communication unit 302 includes, for example, a transmission processing unit that transmits a control signal and / or a data signal to a BH line linked up with another node 3, and a control signal and / or a data signal from the linked wireless link. It may be provided with at least one of a reception processing unit for receiving the data.

In other words, the wireless communication unit 302, which is an example of the processing unit, processes the downlink radio signal received by the antenna 360 and transmits it from the antenna 360 to the downstream node 3, and the uplink radio signal received by the antenna 360. At least one of the process of processing and transmitting from the antenna 360 to the upstream node 3 may be performed. Here, the antenna 360 that receives the downlink radio signal and the antenna 360 that transmits the uplink radio signal may be the same or different from each other.

The processing of the wireless communication unit 301 and / or the wireless communication unit 302 may be different for each node 3. For example, CN3 and SN3 may be processed differently from each other. Further, the processing of the wireless communication unit 301 and / or the wireless communication unit 302 may be changed depending on the direction and / or use of information transmission of the wireless network.

The wireless communication unit 301 and / or the wireless communication unit 302 may have a MIMO function. For example, when the wireless communication unit 302 has a MIMO function, the wireless communication unit 302 operates for transmitting and receiving signals with the upstream node on the BH line, and / or signals with the downstream node on the BH line. Part of the transmission / reception operation may be performed at the same time.

For example, in the above-mentioned SN # 1, the wireless communication unit 302 has an antenna 360-1 having directivity toward CN # 0 (see FIG. 4) and an antenna 360-2 having directivity toward SN # 2. It may be provided for each of (see FIG. 4). SN # 1 may include transmission / reception circuits for two systems, a signal transmitted / received by the antenna 360-1 and a signal transmitted / received by the antenna 360-2. For example, by having the above-mentioned wireless communication unit 302 of SN # 1 having a MIMO function, it can be realized by a transmission / reception circuit for one system (for example, wireless communication unit 302).

The wired communication unit 303 may include, for example, a transmission unit that transmits a control signal and / or a data signal to the backbone network 5, and a reception unit that receives a control signal and / or a data signal from the backbone network 5.

The control unit 304 comprehensively controls the operation of the node 3. For example, the control unit 304 gives a control signal to any one or more of the wireless communication unit 301, the wireless communication unit 302, and the wired communication unit 303, so that the wireless access line, the wireless BH line, and the wired line can be connected. Control communication via any one or more.

The control unit 304 is realized, for example, by the processor 31 shown in FIG. 3 reading a program stored in the storage unit 305 and executing the read program.

The storage unit 305 stores, for example, the node identification information described above and the route metric described later. As will be described later, when the transmission power value of the source node 3 is not included in the route construction packet, the transmission power value of the source node 3 may be stored in the storage unit 305.

(Configuration example of control unit 304)
As shown in FIG. 6, the control unit 304 may optionally include a scan processing unit 341, a node management unit 342, a tree route control unit 343, and an IPT control unit 344.

For example, the scan processing unit 341 scans and discovers the existence of another node 3 located in the vicinity (neighborhood) of the node 3 in response to the activation of the node 3. The scan may be a passive scan or an active scan. Taking a passive scan as an example, a beacon signal is generated in the scan processing unit 341 and transmitted to the surrounding area through the wireless communication unit 302.

The node 3 existing at a position where the beacon signal can be received is referred to as a "neighboring node 3" or a "neighboring node 3".

The beacon signal typically includes information that explicitly or implicitly indicates the SSID (Service Set Identifier) or BSSID (Basic SSID), the transmission cycle of the beacon signal, and the available channels (frequency), respectively. You can. For convenience, this information may be referred to as "BSS (Basic Service Set) related information".

In the case of active scanning, the probe request signal may be generated by the scan processing unit 341 and transmitted to the peripheral area through the wireless communication unit 302. The probe request signal is used, for example, to prompt the peripheral node 3 to transmit a beacon signal. An active scan may be performed if the beacon signal is not received within a certain period of time in the passive scan.

The node management unit 342 stores, for example, information on peripheral nodes 3 (for example, node identification information and BSS-related information) found by scanning by the scan processing unit 341 in the storage unit 305. In each node 3, the information of the peripheral node 3 (hereinafter, may be abbreviated as "peripheral node information") is stored in the storage unit 305, so that, as will be described later, a plurality of nodes 3 are connected to each other in the BH network. A mesh link that links in a mesh shape is constructed by a wireless link.

Even if it is understood that "mesh link construction" means that a plurality of available wireless links are established or linked up between the nodes 3 located in the area where wireless communication is possible with each other. Good. Therefore, the peripheral node information may be regarded as indicating the information of the wireless link available between the nodes 3. The "wireless link information" may be abbreviated as "link information" for convenience.

The tree route control unit 343 controls the construction and update of the tree route on the mesh link by transmitting the route control packet on the mesh link.

The IPT control unit 344 controls the packet transmission timing by the wireless communication unit 302 for the BH line according to the transmission cycle according to the frequency reuse interval, for example.

(Configuration example of tree route control unit 343)
As illustrated in FIG. 6, the tree route control unit 343 may include, for example, a route control packet generation unit 3431, a route metric calculation unit 3432, and a tree route update unit 3433.

The route control packet generation unit 3431 generates a route control packet. The route control packet is an example of a control signal generated in CN3 and propagated to each node 3 starting from CN3 in the BH network.

For example, the CN3 floods the control signal to each of the wireless links linked up in the CN3. When the SN3 receives a control signal from any of the wireless links linked up in the SN3, the SN3 floods the control signal to each of the wireless links linked up in the SN3. In this way, the control signal transmitted from CN3 propagates or transmits the mesh link sequentially or in a chain.

Similarly, the SN3 waits for the arrival (reception) of the control signal while maintaining the link-up state of the wireless link with the CN3 or another SN3. Then, when the control signal is received from the wireless link in the link-up state, the control signal is transmitted to another wireless link in which the link-up state is maintained.

The SN3 may add information to be transmitted to the other SN3 to the control signal transmitted to the other wireless link whose link-up state is maintained. A non-limiting example of the information added to the control signal is the route metric calculated by the route metric calculation unit 3432. Further, the SN3 may exclude the wireless link that has received the control signal from the candidates for the transmission destination of the control signal among the wireless links linked up in the SN3. This makes it possible to prevent the control signal from being transmitted unnecessarily or redundantly through the mesh link.

The route control packet may include, for example, a route construction packet and a reset packet. The types of these packets may be identified, for example, by the type value of the packet header.

The route construction packet is, for example, a packet transmitted when constructing or updating a tree route. The route construction packet may cumulatively include the route metrics calculated at each of the nodes 3 to which the route construction packet has propagated. For example, the node 3 may include the route metric from the core node to the node immediately before the own node in the route construction packet and transmit it.

Upon receiving the route construction packet, the SN3 selects the information of the wireless link to be registered in the tree route from the wireless links that form a mesh link and can be used with the peripheral node 3 based on the cumulative route metric. ..

The reset packet is, for example, a packet transmitted when CN3 requests SN3 to clear the tree path constructed in the mesh link. Upon receiving the reset packet, the SN3 deselects the information of the wireless link selected for the tree path.

The route metric calculation unit 3432 calculates, for example, the propagation quality index of the radio link with the peripheral node 3 that is the source of the received route construction packet, and sets the route metric included in the received route construction packet. The new route metric is obtained by adding the calculation result.

As an example, RSSI (Received Signal Strength Indicator) may be used as the propagation quality index of the radio link between the nodes 3.

For example, when the new route metric calculated by the route metric calculation unit 3432 is smaller than the old route metric, the tree route update unit 3433 can use the upstream radio link corresponding to the new route metric in the peripheral node information as a valid tree route. Select to.

For example, in SN3, when route construction packets are received from each of the different routes, the route metric of one or more radio links propagated by each of the route construction packets is calculated by the route metric calculation unit 3432 for each of the different routes. Will be done.

The tree route update unit 3433 data signals the radio link corresponding to one of the different routes that received the route construction packet among the radio links linked up in the SN based on the route metric calculated separately for the different routes. Select the route used for transmission.

Since the tree path constructed in the mesh link has a tree structure, there is always one upstream node 3 for each SN3. Therefore, the tree route update unit 3433 determines, for example, whether the wireless link (link information) with the upstream node 3 in the mesh link is selected as the wireless link registered in the tree route or deselected. You can build or update routes.

<Operation example>
Hereinafter, an operation example of the wireless communication system 1 described above will be described.

(Link setup procedure)
FIG. 7 is a flowchart showing an example of a link setup procedure between the nodes 3 (in other words, a wireless BH line in the BH network) according to the embodiment.

As illustrated in FIG. 7, in the BH network, each of the nodes 3 including the CN and the SN has a node (hereinafter sometimes referred to as a “peripheral node”) 3 existing in the periphery by, for example, IBSS mode, depending on the activation. Scan (S11).

"IBSS" is an abbreviation for "Independent Basic Service Set". The IBSS mode is sometimes referred to as an ad hoc mode. The "startup" of the node 3 may include turning on the power of the node 3 and restarting by resetting the node 3. Further, the "startup" of the node 3 may include a restart triggered by addition, deletion, change of position, etc. of the node 3 in the wireless communication system 1.

For example, in the scan process S11, each of the nodes 3 starts transmitting the beacon signal to the peripheral area according to the activation. The beacon signal is generated, for example, by the scan processing unit 341 of the control unit 304 and transmitted from the BH line antenna 360 (wireless communication unit 302).

In the scan process S11 in the IBSS mode, in order to avoid collision between the beacon signals, each of the activated nodes 3 alternately transmits the beacon signal (for example, at the timing managed by the node 3 in a pseudo-random number). You can do it.

The node 3 that has received the beacon signal transmitted by the other node 3 stores the information included in the received beacon signal in, for example, the storage unit 305 (S12). The transmission and reception of the beacon signal may be performed for each channel on which the node 3 operates (in other words, an available channel).

Therefore, the scan process (S11) may be referred to as a "channel scan". The node 3 that has received the beacon signal may stop transmitting the beacon signal for the channel that has received the beacon signal.

Information on peripheral nodes 3 (hereinafter referred to as "peripheral node information") that can be communicated by a wireless link by storing BSS-related information included in a beacon signal received from each of the other nodes 3. There is) can be managed. By storing and managing peripheral node information, the individual nodes 3 manage the available wireless links (which may be read as "channels") in the individual nodes 3, for example, as shown in FIG. As a result, the link setup of the wireless BH line is completed, and the mesh link is linked up in the BH network.

As described above, a mesh-shaped wireless link using the IBSS mode is formed (or constructed) between the nodes 3. As described above, the mesh-like wireless link constructed by using the IBSS mode may be referred to as an IBSS mesh link.

As described above, in the examples of FIGS. 1A and 1B, the antenna 360 of CN # 0 in the node 3 has directivity toward SN # 1, which is the node 3 on the downstream side. The antenna 360-1 of the SN # 1 has directivity toward the node 3 on the upstream side, CN # 0. Therefore, in the link setup procedure, the beacon signal transmitted by CN # 0 does not have to be received by SN # 1 and by a node 3 different from SN # 1. Further, the beacon signal transmitted by SN # 1 may be received by CN # 0.

The link setup procedure shown in FIG. 7 is an example of constructing a mesh link by transmitting and receiving a beacon signal between the nodes 3, but the present invention is not limited to this. For example, other signals may be used to construct the mesh link. Alternatively, the mesh link may be set manually according to the installation position of the node 3.

FIG. 8 is a diagram showing a first example of a mesh link in the wireless communication system shown in FIGS. 1A and 1B.

As shown in FIG. 8, the radio link available to CN # 0 may be identified as the radio link between CN # 0 and SN # 1. Further, each available wireless link of SN # 1 to SN # 6 may be determined by the reach of the beacon signal transmitted by each node 3.

Even when the antenna 360 of CN # 0 has directivity toward SN # 1, the beacon signal transmitted by CN # 0 may be received by a node 3 different from SN # 1. Further, the beacon signal transmitted by the node 3 different from the SN # 1 may be received by the CN # 0. In such a case, the wireless link available to CN # 0 may include a wireless link between node 3 and CN # 0, which is different from SN # 1.

FIG. 9 is a diagram showing a second example of the mesh link in the wireless communication system shown in FIGS. 1A and 1B.

Unlike FIG. 8, in FIG. 9, the wireless link available to CN # 0 may include a wireless link between CN # 0 and SN # 2.

(Tree route control over IBSS mesh link)
Next, the tree route control on the IBSS mesh link will be described.

(CN operation example)
FIG. 10 is a flowchart showing an operation example of CN3 including tree route control on the IBSS mesh link according to the embodiment. The flowchart of FIG. 10 may be regarded as being executed by the control unit 304 of CN3 (for example, the tree route control unit 343).

As shown in FIG. 10, the control unit 304 of CN3 monitors, for example, whether or not a specific event has been detected (S31; NO). The "specific event" may include, for example, that CN3 has been activated, that the reset button has been operated, and that a specific timing has arrived. An example of "specific timing" is, for example, a transmission timing set for transmitting a route control packet periodically or irregularly.

The transmission cycle when the route control packet is periodically transmitted may be constant, and the tree route constructed in the present embodiment is asymptotically stable. Therefore, it depends on the number of times the flowchart of FIG. 10 is executed. May be changed. Further, for example, as shown in FIGS. 1A and 1B and FIGS. 2A and 2B, when the construction of the outer wall of one floor is completed and the construction of the next floor is started, the height of the tower crane is increased. A predetermined time may be set to a "specific timing" so that the tree path is updated when it is changed or when the number of nodes 3 increases (or decreases) as the construction work progresses. , May be set by the user of the wireless communication system 1.

When a specific event is detected (S31; YES), the control unit 304 of the CN3 generates a route control packet, and the route control packet is sent to the peripheral SN3 identified based on the peripheral node information, for example, through the wireless communication unit 302. Is transmitted (broadcast) (S32).

For example, when the activation of CN3 is detected and the transmission timing of the route construction packet is detected, the route construction packet is transmitted to the peripheral SN3. When the operation of the reset button is detected and when the transmission timing of the reset packet is detected, the reset packet is transmitted to the peripheral SN3.

After transmitting the route control packet, the control unit 304 monitors, for example, whether or not a certain time has elapsed (timeout) (S33). If no timeout is detected (S33; NO), the control unit 304 may shift the process to S31.

On the other hand, when the passage of a certain time is detected (S33; YES), the control unit 304 may start transmitting the data packet (S34).

As described above, the CN3 transmits (broadcasts) a route control packet to each of the plurality of wireless links linked up with the peripheral node 3, thereby transmitting the route control packet to each of the SN3s constituting the BH network. Propagate.

As shown in FIG. 8, when the wireless link in which CN # 0 can be used is specified as the wireless link between CN # 0 and SN # 1, the peripheral node information of CN # 0 includes SN. # 1 is included, and SN different from SN # 1 is not included. In this case, the route control packet transmitted by CN # 0 may be received by SN # 1.

Further, as shown in FIG. 9, the wireless links that can be used by CN # 0 are the wireless link between CN # 0 and SN # 1 and the wireless link between CN # 0 and SN # 2. When is included, the peripheral node information of CN # 0 may include SN # 1 and SN # 2. In this case, the route control packet transmitted by CN # 0 may be received by SN # 1 and SN # 2. In the present embodiment, the antenna 360 of CN # 0 has directivity toward SN # 1, which is the node 3 on the downstream side, and the antenna 360-1 of SN # 1 has the directivity toward the node 3 on the upstream side. It has a directivity toward CN # 0. Therefore, the reception quality of the route control packet received by SN # 1 is higher than the reception quality of the route control packet received by SN # 2. For example, the radio wave propagation loss of the route control packet received by SN # 1 is smaller than the radio wave propagation loss of the route control packet received by SN # 2.

(Example of SN operation)
Next, an operation example of the SN3 will be described with reference to FIG. FIG. 11 is a flowchart showing an operation example of the SN3 including the tree route control on the IBSS mesh link according to the embodiment. The flowchart of FIG. 11 may be regarded as being executed by the control unit 304 of the SN3 (for example, the tree route control unit 343).

The SN3 monitors, for example, whether or not the route control packet is received by the wireless communication unit 302 (S51; NO).

When the reception of the route control packet is detected (S51; YES), the control unit 304 of the SN3 confirms the type of the route control packet. For example, the control unit 304 confirms whether the received route control packet is a reset packet or a route construction packet (S52 and S54).

When the received route control packet is a reset packet (S52; YES), the control unit 304 performs initialization processing (S53). The initialization process may include, for example, the following process.
-Deselect the link selected as a valid tree route in the peripheral node information-Initialize the stored route metric to the initial value (for example, maximum value)

After the initialization process, the control unit 304 transmits (floods) the received reset packet to the peripheral SN3 (S53a), for example. An identifier (ID) may be included in the reset packet. Each of the nodes 3 may store the ID included in the received reset packet.

When each of the nodes 3 indicates that the ID of the received reset packet matches the stored ID, in other words, it is a reset packet transmitted (transferred) in the past, further transmission of the reset packet is performed. Not performed. This prevents the reset packet from looping in the BH network.

On the other hand, when the received route control packet is not a reset packet (S52; NO), the control unit 304 confirms whether or not the route control packet is a route construction packet (S54).

When the received route control packet is a route construction packet (S54; YES), the control unit 304 refers to the peripheral node information (S55), and the propagation quality index (for example, radio wave propagation loss) of the link that received the route construction packet. Is calculated (S56).

Based on the calculated radio wave propagation loss, the control unit 304 calculates the route metric (S57). For example, the control unit 304 calculates the cumulative radio wave propagation loss as a new route metric by adding the calculated radio wave propagation loss and the propagation quality index included in the received route construction packet.

Then, the control unit 304 compares the new route metric with the old route metric stored before the new route metric is calculated, and determines whether or not the route metric needs to be updated (S58).

For example, the control unit 304 determines that the old route metric is updated to the new route metric when the new route metric is smaller than the old route metric (S58; YES). In response to this determination, the control unit 304 selects the upstream radio link corresponding to the new route metric in the peripheral node information as a valid tree route (update of selection link; S59).

In response to the update of the selection link, the control unit 304 transmits (broadcasts), for example, a route construction packet including the new route metric to the peripheral SN3 identified in the peripheral node information (S60).

After that, the control unit 304 monitors whether or not a certain time has elapsed (timeout) (S61). When the timeout is not detected (S61; NO), the control unit 304 may shift the process to the reception monitoring process (S51) of the route control packet. When a timeout is detected (S61; YES), the control unit 304 may start the data packet transmission process (S62).

When the received route control packet is neither a reset packet nor a route construction packet (S52 and S54; NO), the control unit 304 may shift the process to the reception monitoring process (S51) of the route control packet.

Further, even when the calculated new route metric is equal to or higher than the old route metric and it is determined that the update of the selected link is unnecessary (S58; NO), the control unit 304 shifts the processing to the reception monitoring process (S51) of the route control packet. You may migrate.

As described above, the SN3 selects one of the plurality of wireless links linked up with the peripheral node 3 based on the route metric in response to the reception of the route construction packet. As a result, a tree route based on the route metric is constructed and updated in the BH network to which the mesh link is linked up.

The tree route control shown in FIGS. 10 and 11 is an example, and the present invention is not limited thereto. For example, the construction and updating of tree routes may be controlled manually. For example, the administrator of the wireless communication system 1 may set a tree route in advance according to the respective positions of the nodes 3 and / or the radio wave condition of the nodes 3 after the nodes 3 are installed. In this case, the link setup procedure shown in FIG. 7 and the tree route control shown in FIGS. 10 and 11 need not be executed.

As shown in FIG. 8, when the wireless link in which CN # 0 can be used is specified as the wireless link between CN # 0 and SN # 1, SN # 1 is transmitted by CN # 0. Receive the route construction packet. In this case, SN # 1 selects the wireless link between CN # 0 and SN # 1 as a valid tree path, so that SN # 1 is selected as the downstream node (next hop destination) of CN # 0. Ru.

FIG. 12 is a diagram showing an example of a tree route constructed in the first example of the mesh link shown in FIG. By selecting the wireless link between CN # 0 and SN # 1 as a valid tree path, SN # 1 originates from CN # 0 and is a downstream node of CN # 0 (as shown in FIG. 12). A tree route with SN # 1 selected is constructed at the next hop destination).

Further, as shown in FIG. 9, the wireless links that can be used by CN # 0 are the wireless link between CN # 0 and SN # 1 and the wireless link between CN # 0 and SN # 2. When, both SN # 1 and SN # 2 may receive the route-building packet transmitted by CN # 0. In the present embodiment, the antenna 360 of CN # 0 has directivity toward SN # 1, which is the node 3 on the downstream side, and the antenna 360-1 of SN # 1 has the directivity toward the node 3 on the upstream side. It has a directivity toward CN # 0. Therefore, the reception quality of the route construction packet received by SN # 1 from CN # 0 is higher than the reception quality of the route construction packet received by SN # 2 from CN # 0. For example, the radio wave propagation loss of the route construction packet received by SN # 1 from CN # 0 is smaller than the radio wave propagation loss of the route construction packet received by SN # 2 from CN # 0.

In such cases, the route metric for the direct route between CN # 0 and SN # 2 includes the radio link between CN # 0 and SN # 1 and with CN # 0 via SN # 1. Greater than the route metric of the route to and from SN # 2. Therefore, SN # 2 does not select the radio link between CN # 0 and SN # 2 as a valid tree path, but instead chooses the radio path between CN # 0 and SN # 2 via SN # 1. Select a valid tree path.

FIG. 13 is a diagram showing an example of a tree route constructed in the second example of the mesh link shown in FIG. SN # 2 starts from CN # 0 and is CN, as shown in FIG. 12, by selecting the radio path between CN # 0 and SN # 2 via SN # 1 as a valid tree path. A tree route in which SN # 1 is selected is constructed at the downstream node (next hop destination) of # 0.

As described above, the wireless communication system 1 of the present embodiment has a plurality of nodes 3 including CN # 0, SN # 1, and SN # 2. The horizontal plane on which CN # 0 is located is different from the horizontal plane on which SN # 1 is located. CN # 0 includes an antenna 360 having directivity toward SN # 1. SN # 1 has an antenna 360-1 and an antenna 360-2. Antenna 360-1 has directivity towards CN # 0. The control unit 304 of the SN # 1 processes the downlink radio signal received by the antenna 360-1 and transmits the downlink radio signal from the antenna 360-2 to the SN # 2, and the uplink radio signal received by the antenna 360-2. At least one of the process of processing and the process of transmitting from 360-1 to CN # 0 is performed. With this configuration, CN # 0 establishes a wireless link with SN # 1, and CN # 0 communicates wirelessly with SN # 2, which is difficult to connect directly with CN # 0, via SN # 1. Therefore, a three-dimensional radio route including the height direction can be easily constructed.

Further, in the above-described embodiment, an example in which SN # 1 is provided on the tower crane has been described. Since the tower crane autonomously changes its height according to the progress of the construction work, even if the construction progresses to the upper floors by installing SN # 1 on the tower crane, for example. It is not necessary to newly set the installation position of SN # 1, and a three-dimensional wireless route can be easily constructed.

Further, in the above-described embodiment, since the antennas having the directivity of CN # 0 and SN # 1 have a degree of freedom in the direction of the directivity, CN # 0 and SN # 1 depend on the progress of the construction work. Even if there is a change in the positional relationship, the radio route can be maintained by fine-tuning the direction of directivity.

Further, in the above-described embodiment, the wireless communication environment can be constructed without connecting the nodes by wire. Therefore, for example, when the temporary (or provisional) wireless communication environment has finished its role, the removal is performed. It can be done easily.

The tower crane shown in the above-described embodiment shows an example of a so-called mast climbing type in which the pedestal of the tower crane is provided outside the area of the building, but the present disclosure is not limited to this. For example, the tower crane may be a so-called floor climbing type in which the pedestal of the tower crane exists inside the area of the building. In the case of the floor climbing type tower crane as well as the mast climbing type, since the swivel base of the tower crane is located above the top layer of the building, the SN3 is used as the swivel base as in the above-described embodiment. It may be provided.

Further, in the above-described embodiment, an example in which one tower crane is provided is shown, but a plurality of tower cranes may be provided. In this case, the SN3 may be provided on each of the plurality of tower cranes, may be provided on a part of the plurality of tower cranes, or one SN3 may be provided on the tower crane closest to the CN3. May be good. For example, in this case, the directivity of the antenna of the CN3 may be directed to the SN3 of the tower crane closest to the CN3, or may be directed to the SN3 of the tower crane having the best wireless communication environment with the CN3. .. For example, when the antenna of the CN3 has a configuration in which the directivity can be directed in a plurality of directions or the directivity can be switched in time, the directivity may be directed to each of the SN3s of the tower crane. Further, when SN3 is provided in a plurality of tower cranes, a wireless link between SN3 of one tower crane and SN3 of another tower crane may be included in the tree path.

In the above-described embodiment, the construction site of the building has been described as an example, but the present invention is not limited thereto. The present invention may be applied to an environment for constructing a three-dimensional radio route including the height direction. For example, the present invention may be applied to a site of civil engineering work such as mining an underground tunnel. Even when civil engineering work progresses underground, by applying the present invention, for example, a three-dimensional wireless route can be established between a CN provided above ground and an SN provided underground. Can be built.

1 Wireless communication system 3 Wireless node 5 Backbone network 7 Terminal equipment 31 Processor 32 Memory 33 Storage 34 Input / output (I / O) equipment 35, 36 Wireless interface (IF)
37,39 Wired Interface (IF)
38 Bus 301, 302 Wireless communication unit 303 Wired communication unit 304 Control unit 305 Storage unit 341 Scan processing unit 342 Node management unit 343 Tree route control unit 344 IPT control unit 350, 360 Antenna 3431 Route control packet generation unit 3432 Route metric calculation unit 3433 Tree route update section

Claims (9)

The core node located in the first horizontal plane and
A wireless repeater located on a second horizontal plane different from the first horizontal plane,
Equipped with a radio located on the third horizontal plane,
The core node
A first antenna having directivity toward the wireless repeater is provided.
The wireless repeater
A second antenna having directivity toward the core node,
With the third antenna
The process of processing the downlink radio signal received by the second antenna and transmitting it from the third antenna to the radio, and the process of processing the uplink radio signal received by the third antenna from the second antenna. A processing unit that performs at least one of the processing of transmitting to the core node, and
A wireless communication system equipped with. The third antenna has directivity toward the radio.
The wireless communication system according to claim 1. The processing unit has a transmission / reception circuit by MIMO (Multi-Input Multi-Output).
The wireless communication system according to claim 1 or 2. The processing unit
The radio repeater and the core node are subjected to processing based on information regarding propagation loss of each radio link between the radio repeater and the core node and between the radio repeater and at least one radio. Select the wireless link between them as a relay target,
The wireless communication system according to any one of claims 1 to 3. The core node is located outside a building for which at least some exterior wall construction has not been completed.
The second horizontal plane on which the wireless repeater is located corresponds to a position above the uppermost layer in the range where the outer wall construction of the building is completed.
The wireless communication system according to any one of claims 1 to 4. The wireless repeater is provided at a position above the building in a construction machine installed above or around the building.
The wireless communication system according to claim 5. The construction machine is a crane,
The wireless communication system according to claim 6. The third horizontal plane on which the radio is located is within the height of the floor where the outer wall construction of the building has been completed.
The wireless communication system according to claim 5 or 6. A wireless node located on the first horizontal plane
A first antenna having directivity toward a core node located in a second horizontal plane different from the first horizontal plane,
With the second antenna
The process of processing the downlink radio signal received by the first antenna and transmitting it from the second antenna to the radio, and the process of processing the uplink radio signal received by the second antenna from the first antenna. A processing unit that performs at least one of the processing of transmitting to the core node, and
Wireless node with.

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