WO2014141439A1

WO2014141439A1 - Radio communication device and wireless multihop network system

Info

Publication number: WO2014141439A1
Application number: PCT/JP2013/057238
Authority: WO
Inventors: 芳樹松浦; 悠一五十嵐; 弘起佐藤
Original assignee: 株式会社日立製作所
Priority date: 2013-03-14
Filing date: 2013-03-14
Publication date: 2014-09-18

Abstract

Provided is a radio communication device constituting a tree-shaped wireless multihop network, the radio communication device having: a synchronization unit for synchronizing time-related timing between the radio communication device and another radio communication device; a transmission data management unit for managing data to be transmitted to the other radio communication device in correlation with priority of the data; a transmission unit for transmitting prescribed data stored in the transmission data management unit to the other radio communication device; a receiving unit for receiving data transmitted from the other radio communication device; and a transmission/reception control unit for switching, at prescribed timing, to a radio communication channel correlated with the priority of the data, and controlling the transmission or reception of data having the priority concerned.

Description

Wireless communication apparatus and wireless multi-hop network system

The present invention relates to a technology of a wireless communication device and a wireless multi-hop network system.

In recent years, wireless communication using narrowband frequencies for automatic meter reading systems that monitor power consumption remotely, equipment remote monitoring systems that monitor the status of equipment in factories, or systems that collect information from equipment distributed over a wide area Is being considered. Narrowband frequencies using the 920 MHz band and the like are advantageous for obstacle avoidance and long-distance communication, although the communication speed is relatively slow.

Construction of the above system using a plurality of wireless communication devices (hereinafter sometimes referred to as “nodes”) is being studied. In the system, a plurality of nodes transmit sensor information, device information, and the like to the management node. Here, a node whose wireless communication does not reach the management node directly transmits these information to the management node via other nodes. That is, it is considered to construct a wireless multi-hop network system in which a plurality of nodes are connected in a tree shape by wireless communication.

In such a system, data is not always transmitted from a plurality of nodes to the management node. For example, in the event of a node failure or emergency, the management node sends a control command or the like to a predetermined node to inquire about the situation. The predetermined node notifies the management node of information relating to the abnormal state. It is desirable that data including such urgent information is preferentially communicated with respect to data that is normally transmitted and received.

For example, Patent Document 1 describes that a communication time for preferential data and a communication time for normal data are divided in advance. Patent Document 2 describes that different frequencies are used for preferential data communication and normal data communication.

JP 2000-253017 A Japanese Patent No. 4,904,849

For example, when data including urgent information is set as priority data, the priority data is not frequently transmitted / received, and the rate at which normal data is transmitted / received is most. Therefore, unless the transmission / reception between the preferential data and the normal data is performed in a well-balanced manner, the efficiency of the normal data transmission / reception may be greatly reduced.

Therefore, an object of the present invention is to provide a wireless communication apparatus and a wireless multi-hop network system that perform preferential data communication and normal data communication in a balanced manner. Another object of the present invention is to provide a wireless communication apparatus and a wireless multi-hop network system that allow high priority data to reach a transmission destination in as short a time as possible.

A wireless communication apparatus according to an embodiment of the present invention is a wireless communication apparatus that constitutes a tree-shaped wireless multi-hop network, and a synchronization unit that synchronizes timing with other wireless communication apparatuses, A transmission data management unit that manages data to be transmitted to the wireless communication device in association with the priority of the data, and predetermined data stored in the transmission data management unit is transmitted to another wireless communication device. A transmission unit, a reception unit that receives data transmitted from another wireless communication device, and at a predetermined timing, switches to a wireless communication channel associated with the priority of the data, and transmits data of the priority or A transmission / reception control unit for controlling reception;

According to the present invention, preferential data communication and normal data communication can be performed in a balanced manner. In addition, high priority data can reach the transmission destination in as short a time as possible.

1 is a configuration example of a wireless multi-hop network system. The hardware structural example of a radio | wireless communication apparatus. Hardware configuration example of the gateway. The data structural example of transmission data management information. The data structural example of self-node transmission timing information. Data configuration example of node information. The data structural example of reception flag information. The data structural example of all node transmission timing information. Configuration example of superframe. Example of frame configuration. A configuration example of a time slot. An operation example when it is determined that data is transmitted / received in each divided time slot. Packet data configuration example. The flowchart example of the process in a transmission / reception control part. The flowchart example of the process of the transmission data acquisition part in a radio | wireless communication apparatus. The flowchart example of the process of the transmission data acquisition part in a gateway. The flowchart example of the transmission process of a transmission part. The flowchart example of the reception process of a receiving part. An example of the operation of each node when data with a high priority is transmitted from the node A to the node e when the frame of the node c is executed. The operation example of each node in the case where data having a high priority is transmitted from the node e to the node A when the frame of the node d is executed. The operation example of each node in the case where data of priority “high” is transmitted from the node e to the node A when the frame of the node f is executed. An example of the operation of each node when data of priority “high” is transmitted from the node A to the node h when the frame of the node d is executed. 10 is a configuration example of a wireless multi-hop network system in which an obstacle exists in part according to the second embodiment. An example of a time slot related to transmission / reception of high priority data. 6 shows an example data structure of an address packet and a data packet. 10 is a flowchart example of a transmission process of a transmission unit according to the second embodiment. 10 is a flowchart example of a reception process of a reception unit according to the second embodiment.

Hereinafter, a wireless communication apparatus and a wireless multi-hop network system that transmit and receive data by switching wireless communication channels at a predetermined timing based on data priority will be described with reference to the drawings.

FIG. 1 shows a configuration diagram of a wireless multi-hop network system. A wireless multihop network system (hereinafter referred to as “wireless network”) 100 includes a gateway 101A and a plurality of wireless communication devices 102a to 102j. The wireless network 100 has a structure in which, for example, a plurality of wireless communication devices 102a to 102j are connected by wireless communication in a tree shape with the gateway 101A as the highest level. In the wireless network 100 shown in FIG. 1, a solid line connecting the wireless communication devices indicates a communication path capable of wireless communication. Hereinafter, the wireless communication devices 102a to 102j may be collectively referred to as the wireless communication device 102. The gateway 101A and the wireless communication device 102 may be referred to as nodes.

The gateway 101A is directly or indirectly connected to each wireless communication device 102. The gateway 101A is connected to the control server 130 via the network 120. The gateway 101A manages the communication timing of the wireless communication apparatus 102 and relays between the wireless communication apparatus 102 and the control server 130. For example, the gateway 101 </ b> A receives data transmitted from each wireless communication device 102 located at a lower rank in the network topology, and transmits the data to the control server 130. The gateway 101 </ b> A transmits a control command or the like transmitted from the control server 130 to the wireless communication apparatus 102. The gateway 101 </ b> A receives response data for the control command transmitted from the wireless communication apparatus 102 and transmits the response data to the control server 130.

The wireless communication device 102 transmits data (for example, sensor information or device state information) generated by itself to another wireless communication device 102. The wireless communication device 102 transfers the data received from the other wireless communication device 102 to another wireless communication device 102 (or gateway 101A) different from the data.

The control server 130 has a function of managing the entire wireless network. For example, the control server 130 manages various information collected from the wireless communication apparatus 102 via the gateway 101A, or transmits a control command to the wireless communication apparatus 102 via the gateway 101A.

The network 120 is a network different from the wireless network 100. The network 120 includes, for example, the Internet and / or a LAN (Local Area Network).

In the wireless network 100, a certain node can transmit / receive data only to / from neighboring nodes existing within a wireless communication possible range. Accordingly, data generated by a certain node is relayed (transferred) in a bucket relay manner by another node and is carried to a destination (destination) node.

For example, when the node A shown in FIG. 1 receives data having the node e as the transmission destination from the control server 130, the data is first transferred to the node a capable of wireless communication. The data transferred to the node a is then transferred to the node b and node c and carried to the destination node e. In this way, transmitting data from the higher rank to the lower rank may be referred to as transmitting data in the “downward” direction.

On the contrary, when the node e generates data having the node A as a transmission destination, the data is first transferred to the node c capable of wireless communication. The data transferred to the node c is then transferred to the node b and the node a and carried to the destination node A. As described above, transmitting data from a lower rank to an upper rank may be referred to as transmitting data in the “upward” direction.

FIG. 2 shows a hardware configuration of the wireless communication apparatus 102. The wireless communication device 102 has a function of performing wireless communication with another wireless communication device 102 and / or the gateway 101A. The wireless communication device 102 includes, for example, a storage unit 201, a sensor unit 202, a central control device 203, a power supply circuit 204, and an RFIF (Radio Frequency Interface) 205. These elements 201 to 205 are connected by a bus 230 capable of transmitting and receiving data in both directions. The wireless communication device 102 may be an embedded device or an independent device.

The sensor unit 202 senses various information. For example, the wireless communication device 102 periodically notifies the control server 103 of sensor information including various sensed information.

The central control device 203 executes various computer programs stored in the storage unit 201. Thereby, various functions of the wireless communication apparatus 102 are realized.

The power supply circuit 204 supplies power to the wireless communication apparatus 102. Thereby, the wireless communication apparatus 102 operates.

RFIF 205 mutually converts a digital signal and a radio signal. That is, the RFIF 205 transmits the generated digital data on a wireless signal to be transmitted to another node, or extracts the digital data from a wireless signal received from another node.

The storage unit 201 includes, for example, a ROM (Read-Only Memory) 210 and a RAM (Random Access Memory) 220. The ROM 210 is configured by, for example, a read-only semiconductor memory.

The ROM 210 stores, for example, various computer programs that are executed in the wireless communication apparatus 102. The ROM 210 stores programs and data such as a transmission / reception control unit 211, a transmission data acquisition unit 212, a transmission unit 213, a reception unit 214, a synchronization unit 215, a path management unit 216, and an application processing unit 217.

The synchronization unit 215 synchronizes timing related to time with another wireless communication apparatus 102. For example, the synchronization unit 215 performs synchronization so that the time has an error of a predetermined value or less between the nodes. This is because if there is an error in the time, the timing of data transmission / reception between nodes differs, and data cannot be transmitted / received correctly.

The route management unit 216 manages the route of the wireless network 100. For example, the path management unit 216 manages in which position the wireless node 100 is located, and which other node is connected to the wireless network 100 in terms of the network topology.

Application processing unit 217 generates data having predetermined information. For example, the application processing unit 217 generates data based on the sensor information acquired from the sensor unit. The generated data is notified to the control server 130, for example.

The transmission unit 213 transmits predetermined data stored in the transmission data management information 222 to other nodes by wireless communication. Details of the transmission unit 213 will be described later.

The receiving unit 214 receives data transmitted from other nodes. Details of the receiving unit 214 will be described later.

The RAM 220 is configured by a rewritable semiconductor memory or the like. The RAM 220 stores data necessary for program execution. The RAM 220 stores programs and data such as a priority queue 221, transmission data management information 222, own node transmission timing information 223, node information 224, and reception flag information 225, for example.

The priority queue 221 manages data to be transmitted as a queue for each priority. The priority queue 221 includes, for example, a queue that manages data with high priority, a queue that manages data with high priority, and a queue that manages data with low priority. .

The transmission data management information 222 manages data to be transmitted to other wireless communication apparatuses 102 in association with priorities. Details of the transmission data management information 222 will be described later.

The own node transmission timing information 223 includes information regarding a timing at which the own node can transmit data. Details of the own node transmission timing information 223 will be described later.

The node information 224 includes information on the network topology position of the wireless network 100 of the own node and the connection relationship with other nodes. Details of the node information 224 will be described later.

The reception flag information 225 includes a flag for managing completion / non-completion of processing for each priority. Details of the reception flag information 225 will be described later.

The transmission / reception control unit 211 switches to a wireless communication channel associated with the priority of data at a predetermined timing, and controls transmission or reception of data with the priority.

The transmission / reception control unit 211 switches to a wireless communication channel corresponding to a certain priority at a predetermined timing, causes the reception unit 214 to wait for reception of data for a predetermined standby time, and A) receives data within the standby time. If not, switch to a wireless communication channel corresponding to a priority lower than a certain priority, and B) If reception of data is started within the waiting time, the same wireless communication channel until reception of the data that has started reception is completed May then be switched to a wireless communication channel corresponding to a priority lower than a certain priority.

After the transmission / reception control unit 211 switches to a wireless communication channel corresponding to a priority lower than a certain priority, the transmission / reception control unit 211 again causes the reception unit 214 to wait for reception of data for a predetermined standby time, and the above A) and B) This determination may be repeated until the time slot, which is a predetermined time, is completed.

When transmitting / receiving data to be transmitted, the transmission / reception control unit 211 first transmits preceding data including an address of a transfer destination of the data to be transmitted (for example, the address packet 1300 illustrated in FIG. 25), and then transmits the data. When the preceding data is not received within the waiting time in the above A) when transmitting the data to be transmitted and waiting for the data reception, or the transfer destination address included in the preceding data is its own wireless communication device If it does not indicate 102, the wireless communication channel corresponding to a priority lower than a certain priority is switched, and in B), the preceding data is received within the waiting time and the transfer included in the preceding data is performed. If the destination address indicates the wireless communication device 102 of the own device, the same wireless communication channel is maintained, and the data to be transmitted after that is transmitted. Receiving the data, then, it may be Kaee cut a wireless communication channel corresponding to a lower priority than some priority.

The transmission / reception control unit 211 identifies data to be transmitted from the transmission data management information 222, and corresponds to the priority of data to be transmitted at a predetermined timing in a time slot in which the wireless communication apparatus 102 can transmit data. The data to be transmitted may be transmitted to the transmission unit 213 by switching to a wireless communication channel.

The transmission / reception control unit 211 can transmit the data to be transmitted when reception of data having a priority higher than the priority of the data to be transmitted is started within the standby time before the timing for transmitting the data to be transmitted. Time slots may be delayed by a certain number of time slots.

The data to be transmitted / received includes a rank 94 indicating a hierarchy in the tree shape of a node that is a transmission source of the data, and a transmission direction 95 indicating whether the data is transmitted in an up or down direction of the tree shape. (See FIG. 13), the transmission / reception control unit 211 includes the transmission direction 95 included in the received data, and the positional relationship between the rank 94 included in the received data and the rank of its own wireless communication device. Based on this, the number of time slots to be delayed may be determined.

When the transmission direction 95 included in the received data is down and the rank 94 included in the received data is higher than the rank of the own wireless communication device 102, the transmission / reception control unit 211 determines the number of time slots. B) If the transmission direction 95 included in the received data is upstream and the rank included in the received data is the same as the rank of the own wireless communication device 102, the number of time slots is set to 1. C) If the transmission direction 95 included in the received data is upstream and the rank 94 included in the received data is lower than the rank of its own wireless communication device 102, the number of time slots is two. It may be delayed.

When switching to a wireless communication channel corresponding to the lowest priority at a predetermined timing, the transmission / reception control unit 211 performs carrier sense on the wireless communication channel, and then transmits data corresponding to the lowest priority to the transmission unit. 213 may be transmitted. Further details of the transmission / reception control unit 211 will be described later.

FIG. 3 shows the hardware configuration of the gateway 101A. The gateway 101A has a function of performing wireless communication with the wireless communication apparatus 102. The gateway 101 </ b> A has a function of communicating with the control server 130 via the network 120.

The gateway 101A includes, for example, a storage unit 301, a sensor unit 302, a central control device 303, a power supply circuit 304, an RFIF 305, and a network IF 306. These elements 301 to 306 are connected by a bus 330 capable of bidirectional data transmission / reception.

The storage unit 301, the sensor unit 302, the central control device 303, the power supply circuit 304, and the RFIF 305 have the same functions as the storage unit 201, the sensor unit 202, the central control device 203, the power supply circuit 204, and the RFIF 205 shown in FIG. Therefore, explanation is omitted.

The network IF 306 is an IF for connecting to the network 120 and transmitting / receiving data to / from the control server 130, for example.

The storage unit 301 includes, for example, a ROM 310 and a RAM 320. The ROM 310 and the RAM 320 have the same functions and configurations as the ROM 210 and the RAM 220 shown in FIG.

The ROM 310 stores programs and data such as a transmission / reception control unit 311, a transmission data acquisition unit 312, a transmission unit 313, a reception unit 314, a synchronization unit 315, a path management unit 316, and an application processing unit 317.

The transmission / reception control unit 311, transmission data acquisition unit 312, transmission unit 313, reception unit 314, synchronization unit 315, and path management unit 316 are the transmission / reception control unit 211, transmission data acquisition unit 212, transmission unit 213, reception shown in FIG. Since the functions are the same as those of the unit 214, the synchronization unit 215, and the route management unit 216, description thereof is omitted.

Application processing unit 317 generates data having predetermined information. For example, the application processing unit 317 generates data based on the sensor information acquired from the sensor unit 302. The generated data is notified to the control server 130, for example. The application processing unit 317 may create data for transmission / reception with the control server 130.

The RAM 320 stores programs and data such as a priority queue 321, transmission data management information 322, all node transmission timing information 323, node information 324, and reception flag information 325, for example.

The priority queue 321, transmission data management information 322, node information 324, and reception flag information 325 have the same functions as the priority queue 221, transmission data management information 222, node information 224, and reception flag information 225 shown in FIG. Since there is, description is abbreviate | omitted.

The all node transmission timing information 323 manages data transmission timing of all nodes. Details of the all-node transmission timing information 323 will be described later.

FIG. 4 shows an example of the data structure of the transmission data management information 222 (322). The transmission data management information 222 (322) is a so-called buffer for waiting for data to be transmitted until the actual transmission timing. In other words, the predetermined data stored in the priority queue 221 (321) is temporarily stored in the transmission data management information 222 (322) until the timing at which the own node can transmit is reached. Then, when it is time for the own node to transmit, the predetermined data stored in the transmission data management information 222 (322) is transmitted. The transmission data management information 222 (322) includes a time slot waiting number 401, a priority 402, data 403, and a transmission direction 404 as data items.

The time slot waiting number 401 stores the number of time slots that should be waited until the data waiting to be transmitted can be transmitted within the frame. The value of the time slot waiting number 401 is normally subtracted by “1” when one time slot ends.

The priority 402 stores the priority of data. For example, the priority 402 stores information of “high”, “medium”, or “low” indicating the high priority. For example, the priority “low” is normally transmitted / received data, the priority “high” is data to be transmitted urgently, and the “medium” priority is data to be transmitted as soon as possible. That is, most data transmitted and received in the wireless network 100 has a low priority.

The data 403 stores data that is actually transmitted. In the transmission direction 404, information indicating the direction of the transmission destination is stored. For example, in the transmission direction 404, either “down” indicating transmission to the lower rank or “up” indicating transmission to the upper rank in the tree-shaped wireless network 10 is stored.

For example, in the row 411a, the data to be transmitted in which the number of timeslot waiting is “0”, the priority 402 is “high”, the data 403 is “POWER_OFF”, and the transmission direction 404 is “downlink” is transmitted data management information 222 ( 322).

FIG. 5 shows an example of the data structure of the own node transmission timing information 223. The wireless communication apparatus 102 holds the own node transmission timing information 223.

The own node transmission timing information 223 holds the frame number that the own node can transmit. The own node transmission timing information 223 has a frame number 411 as a data item. For example, when the frame number assigned to the own node is “1”, “1” is stored in the frame number 411. In this case, when the frame number is in the order of “1” in the transmission / reception schedule, the own node tries to transmit the data generated by the own node.

FIG. 6 shows an example of the data structure of the node information 224 (324). The node information 224 (324) stores information for wireless communication.

The node information 224 (3240 is a data item including a node ID (identification) 421, a parent node ID 422, a child node ID 423, and a rank 424. The node ID 421 stores a value that uniquely identifies the own node. The node ID 422 stores the ID of the node that is the parent of the own node (upward), and the child node ID 423 stores the ID of the node that is a child of the own node (downward). Stores a value indicating which layer on the network topology the node is in.

For example, in the case of the wireless communication apparatus 102a in FIG. 1, as shown in a row 463a, “a” is represented in the node ID 421, “A” representing the gateway is represented in the parent node ID 422, and the child node ID 423 is one level below the own node. “1” is stored in the rank 424 for the node “b, h” connected to.

FIG. 7 shows an example of the data structure of the reception flag information 225 (325). The reception flag information 225 (325) stores a flag for determining whether or not data corresponding to each priority can be received in one frame. The reception flag information 225 (325) has a priority 431 and a flag 432 as data items.

In the priority 431, the height of each priority operated in the wireless network 100 is stored. For example, “high”, “medium”, and “low” indicating the high priority are stored in the priority 431. And then. A value of “TRUE” or “FALSE” is stored for each priority level. “TRUE” indicates that data of the priority can be received in one frame. “FALSE” indicates that data of the priority is not received in the one frame. When the processing shifts to the next frame, all the flags 432 are initialized (reset) to “TRUE”.

FIG. 8 shows an example of the data configuration of all node transmission timing information 323. All node transmission timing information 323 is held by the gateway 101A.

In the all node transmission timing information 323, information on transmission timings of all nodes existing in the wireless network 100 is stored. The all-node transmission timing information 323 has a node ID 501, a rank 502 and a frame number 503 as data items.

The node ID 501 stores the ID of each node. The rank 502 stores the rank of each node. The frame number 503 stores the frame number assigned to each node. That is, the all-node transmission timing information 323 includes information indicating in which frame number 503 each node can transmit data.

For example, the row 465b indicates that the rank 502 of the node ID 501 “b” (that is, the node b) is “2”, and the frame number 503 assigned to the node b is “2”.

Next, a schedule relating to communication in the wireless network 100 (hereinafter referred to as “communication schedule”) will be described with reference to FIGS. The communication schedule indicates at what timing each node should transmit or receive data. That is, each node transmits or receives data at an appropriate timing (time) according to this communication schedule.

FIG. 9 shows the configuration of the super frame 50. The super frame 50 indicates a one-cycle communication schedule for the entire wireless network 100. That is, the communication schedule indicated by the super frame 50 is repeatedly executed in the entire wireless network 100.

The super frame 50 is composed of a plurality of frames 51 arranged in a predetermined order. The frame 51 indicates which node can transmit data in the frame. That is, as shown in FIG. 8, a node is assigned to each frame, and each node can transmit data when the current frame number is the frame number assigned to itself. For example, in the frame 51a in FIG. 9, the node a is in a state where data can be transmitted.

Basically, in one superframe 50, a frame is allocated to all nodes included in the wireless network 100. That is, the super frame 50 includes frames that are equal to or more than the number of nodes included in the wireless network 100. Usually, the super frame 50 is configured by adding a plurality of spare frames to the number of nodes included in the wireless network 100.

Thus, when the super frame 50 is executed for one cycle, all the nodes included in the wireless network 100 normally complete data transmission. In other words, normally, when the super frame 50 is executed for one cycle, the control server 130 can acquire data from all nodes included in the wireless network 100.

FIG. 10 shows the configuration of the frame 51. The frame 51 is composed of a plurality of time slots 52. The time slot 52 indicates a predetermined time at equal intervals. Each node can transmit or receive data during the time slot 52 with other nodes adjacent in the network topology.

Usually, the number of time slots 52 included in one frame 51 is equal to or greater than the number of hops required to transfer data from the lowest rank node to the highest rank node in the network topology.

For example, in the frame 51a allocated to the node a shown in FIG. 10, data is transmitted from the node a to the adjacent upstream node A in the first time slot 52a-1. Since this data reaches the node A in one time slot, the remaining time slots 52a-2 to 52a-6 constituting the frame 51a become standby time as a spare.

For example, in the frame 51d assigned to the node d shown in FIG. 10, data is transmitted from the node d to the adjacent upstream node c in the first time slot 52d-1. Then, data is transmitted from the node c to the node b in the second time slot 52d-2. Then, data is transmitted from the node b to the node a in the third time slot 52d-3. Then, data is transmitted from the node a to the node A in the fourth time slot 52d-4. Here, since the data reaches the node A, the remaining time slots 52d-5 to 52d-6 constituting the frame 51d become standby time as a spare.

FIG. 11 shows the structure of the time slot 52. The time slot 52 is divided into one or more times. Hereinafter, this divided time is referred to as “division time”. A different wireless communication channel (that is, a different frequency band) is assigned to each of the division times. Further, each of the different wireless communication channels is assigned a process for data having a different priority. In the time slot 52 shown in FIG. 11, processing with a priority “high” is assigned to the division time 61, processing with a priority “medium” is assigned to the division time 62, and processing with a priority “low” is assigned to the division time 63. Is assigned.

The node determines the presence / absence of transmission / reception of priority data corresponding to the division time in each division time of the time slot 52. That is, the node switches to the wireless communication channel corresponding to the division time, and determines whether or not data with priority corresponding to the division time is transmitted / received. The time slot 52 has a switching time 60 for switching the wireless communication channel before each divided time.

For example, in the time slot 52 shown in FIG. 11, the switching time 60a is a time for switching to the wireless communication channel corresponding to the priority “high”. The division time 61 is a time for determining transmission / reception of data with high priority. The switching time 60b is a time for switching to the wireless communication channel corresponding to the priority “medium”. The division time 62 is a time for determining transmission / reception of data with the priority “medium”. The switching time 60c is a time for switching to the wireless communication channel corresponding to the priority “low”. The division time 63 is a time for determining transmission / reception of data with a low priority.

FIG. 12 is a diagram for explaining processing when it is determined that data is transmitted / received at each divided time of the time slot.

FIG. 12A shows processing in the time slot when it is determined to transmit / receive data with high priority. When it is determined that the data of the priority “high” is transmitted / received at the division time 61 of the time slot 52 shown in FIG. 11, the processing in the time slot is shown in FIG. That is, when transmission / reception of data having a high priority occurs in the division time 61, the division time 61 is extended until transmission / reception of packet data having a high priority is completed (see the division time 61a).

Thereafter, the wireless communication channel is switched to the low priority wireless communication channel at the switching time 60c, and the remaining time 63 until the time of the time slot 52a ends is assigned to the processing related to transmission / reception of the low priority data. When transmission / reception of data with a high priority occurs in the time slot 52a, processing related to transmission / reception of data with a priority of “medium” is not executed.

FIG. 12B shows the structure of the time slot when it is determined to transmit / receive data with the priority “medium”. In the time slot 52 shown in FIG. 11, when it is determined not to transmit / receive priority “high” data and when it is determined to transmit / receive priority “medium” data at the split time 62, Is the process shown in FIG. That is, if transmission / reception of data with priority “high” does not occur during the division time 61 and transmission / reception of data with priority “medium” occurs during the division time 62, transmission / reception of packet data with priority “medium” is performed. The division time 62 is extended until completion (see the division time 62a).

Thereafter, the wireless communication channel is switched to the low priority wireless communication channel at the switching time 64c, and the remaining time 63 until the time of the time slot 52b ends is assigned to processing related to transmission / reception of the low priority data.

FIG. 12C shows the structure of the time slot when it is determined to transmit / receive data with a priority “low”. When it is determined that the data of priority “high” and “medium” are not transmitted / received at the divided

times

61 and 62 of the time slot 52 shown in FIG. 11, the processing shown in FIG. Become. In other words, when transmission / reception of data with the priority “high” and “medium” does not occur in the

division times

61 and 62, respectively, the wireless communication channel is switched to the wireless communication channel with the priority “low” at the switching time 60c. Then, the remaining time until the time slot ends is assigned to the determination of whether or not data with a low priority is transmitted / received. If transmission / reception of data with a priority “low” occurs during the division time 63a, packet data with a priority “low” is transmitted / received in the remaining time.

When transmitting data with a low priority, CS (career sense) 67 is executed after the switching time 60c. In the transmission of data with the priority “high” shown in FIG. 12A and the priority “medium” shown in FIG. 12B, the CS 67 is not executed. This is because the transmission of the data with the priority “high” and the priority “medium” is managed and configured so that no interference occurs in the entire wireless network 100. In other words, the transmission timing between the nodes of the data with the priority “high” and “medium” is managed and controlled in the entire wireless network 100 according to the communication schedule. That is, the wireless network 100 guarantees the bandwidth of transmission of data with priority “high” and “medium”.

On the other hand, CS67 is executed in advance in the transmission of the data with the priority “low” shown in FIG. This is because transmission of data with a low priority is not managed so that interference does not occur in the entire wireless network 100. In other words, before transmitting data with low priority, execute CS67, and other nodes are not transmitting / receiving data with low priority on the wireless communication channel with low priority. Confirm. In other words, the timing of transmission of data with low priority between nodes may not be managed and controlled in the entire wireless network. That is, the wireless network 100 may make transmission / reception of data with a low priority “best effort”.

FIG. 13 shows an example of the structure of packet data. The packet data 80 includes, for example, a header 81, a payload 82, and inspection data 83.

The header 81 includes, for example, a transfer destination address 91, a transfer source address 92, a transmission destination address 85, a transmission source address 86, a packet length 93, a rank 94, and a transmission direction 95.

The transfer destination address 91 stores an address (for example, an IP address) of a transfer destination node of the packet data 80 (hereinafter also referred to as “transfer destination node”). The transfer source address 92 stores an address of a transfer source node of the packet data 80 (hereinafter also referred to as “transfer source node”).

In the transmission destination address 85, an address of a node that finally receives the packet data 80 is stored. Hereinafter, the node of the transmission destination address may be referred to as “transmission destination node”. The source address 86 stores the address of the node that first transmitted the packet data 80. Hereinafter, the node of the source address may be referred to as “source node”.

In the packet length 93, the length (data size) of the packet data 80 is stored. The packet length 93 stores, for example, the length of subsequent data including the packet length 93 itself.

In rank 84, a value indicating a hierarchy in the wireless network 100 of the transmission source node of the packet data 80 is stored. That is, the value stored in the rank 424 of the node information 224 (324) is stored in the rank 814.

In the transmission direction 815, as described above, a value indicating whether the packet data 80 should be transmitted in the uplink or downlink direction from the transmission source node is stored. For example, “1” may be stored in the transmission direction 815 when the packet data 80 is transmitted in the upstream direction, and “0” may be stored in the transmission direction 815 when the packet data 80 is transmitted in the downstream direction.

In the payload 82, data (for example, application data) carried by the packet data 80 is stored.

In the inspection data 83, a value used for determining whether or not an error has occurred in the packet data 80 and / or correcting the error is stored. This is because the packet data 80 may cause an error due to the influence of noise or the like on wireless communication. The inspection data 830 stores, for example, CRC (Cyclic Redundancy Check).

FIG. 14 shows an example of a flowchart of processing in the transmission / reception control unit 211 (311). FIG. 14 shows processing in one frame.

The transmission / reception control unit 211 (311) sets (initializes) all the flags included in the reception flag information 225 (325) to “TRUE” when it is time to start frame processing (S101). Next, the transmission data acquisition unit 212 (312) performs transmission data acquisition processing (S102). Although details of the transmission data acquisition process (S102) will be described later, in brief, the transmission data acquisition unit 212 (312) stores transmission data in the priority queue 221 (321), and this time When the frame is the transmission timing of the own node, the transmission data is stored in the transmission data management information 222 (322) (S102).

Next, the transmission / reception control unit 211 (311) sets “high” to a flag (hereinafter referred to as “target priority”) indicating the priority of the current processing target (S103), and corresponds to the priority “high”. Switch to the wireless communication channel (S104).

Next, the transmission / reception control unit 211 (311) has a priority corresponding to the target priority among the data stored in the transmission data management information 222 (322) in step S102, and the time slot waiting number 401 is set. It is determined whether or not “0” data exists (S105).

When there is data having a priority corresponding to the target priority and the time slot waiting number 401 is “0” (S105: YES), the transmission / reception control unit 211 (311) transmits the transmission unit 213 (313). To execute the transmission process (S106), and then proceeds to step S113. Although details of the transmission process (S106) will be described later, in this process, the flag corresponding to the priority in the process of the reception flag information 225 (325) is changed to “FALSE”.

No data is stored in the transmission data management information 222 (322), or there is no data corresponding to the target priority (that is, data matching the target priority and the priority), or the time slot waiting number 401 is “ When the data “0” does not exist (S105: NO), the transmission / reception control unit 211 (311) proceeds to the next step S108.

In step S108, the transmission / reception control unit 211 (311) refers to the reception flag information 225 (325) and determines whether the flag corresponding to the target priority is “TRUE” or “FALSE” (S108). .

When the flag corresponding to the target priority is “FALSE” (S107: FALSE), the transmission / reception control unit 211 (311) turns off the reception function (S107), and proceeds to step S109. That is, it is assumed that priority level data corresponding to the target priority level is not received during the current division time.

When the priority flag corresponding to the target priority is “TRUE” (S107: TRUE), the transmission / reception control unit 211 (311) sends the current target to the reception unit 214 (314) during the current division time. The reception of data corresponding to the priority is waited (S109).

When reception of data corresponding to the current priority is started during the current divided time (S109: YES), the transmission / reception control unit 211 (311) performs reception processing (S922) on the reception unit 214 (314). After that, proceed to step S113. Although details of the reception process (S922) will be described later, in this process, the flag corresponding to the target priority is changed to “FALSE” in the reception flag information 225 (325).

If the data corresponding to the current target priority is not received during the current divided time (S109: NO), the transmission / reception control unit 211 (311) lowers the target priority by one (S909), and the step Proceed to S112. That is, if the current target priority is “high”, it is changed to “medium”, and if the current target priority is “medium”, it is changed to “low”.

In step S112, the transmission / reception control unit 211 (311) determines whether or not the target priority is “low” (S112). When the target priority is not “low” (S112: NO), the transmission / reception control unit 211 (311) returns to step S104. That is, the transmission / reception control unit 211 (311) executes the processes of steps S104 to S112 with the target priority lowered by one.

When the target priority is “low” (S112: YES), the transmission / reception control unit 211 (311) switches to a wireless communication channel corresponding to the priority “low” (S113). Then, the transmission / reception control unit 211 (311) waits for reception of data with a priority “low” for the remaining time of the time slot (that is, until the time slot ends). Or the transmission / reception control part 211 (311) performs the transmission process of the data of a priority "low" (S114).

When the end time of the time slot is reached, the transmission / reception control unit 211 (311) subtracts “1” from the number of time slot standbys stored in the transmission data management information 222 (322) (S115). Then, the transmission / reception control unit 211 (311) determines whether or not the frame end time has come (S116).

If it is not the end time of the frame (S116: NO), the transmission / reception control unit 211 (311) advances the time slot by one and returns to the process of step S103. That is, the transmission / reception control unit 211 (311) repeats the above-described processing for the next time slot.

When the frame end time is reached (S116: YES), the transmission / reception control unit 211 (311) ends the process. That is, the transmission / reception control unit 211 (311) ends the process of the current frame and proceeds to the process of the next frame.

Here, when priority “high” and priority “medium” can be transmitted in a frame, data of priority “high” may be preferentially transmitted in the first time slot. Then, after transmitting the high priority data, the medium priority data may be transmitted in the next time slot. The high priority data and the medium priority data may be adjusted in the transmission data management information 222 (322) so that they are not transmitted in the same time slot. For example, the time slot waiting number 401 may be adjusted, or the time slot waiting number 401 may be updated before the end of the time slot.

FIG. 15 is an example of a flowchart showing processing of the transmission data acquisition unit 212 in the wireless communication apparatus 102.

The transmission data acquisition unit 212 determines whether or not data with a priority “high” exists in the priority queue 221 (S201). When data with a priority “high” exists (S201: YES), the transmission data acquisition unit 212 acquires data with a priority “high” from the priority queue 221 (S202), and sets the priority to “high”. The data is set and stored in the transmission data management information 222 (S203), and the process proceeds to step S204. If no data with high priority exists (S201: NO), the transmission data acquisition unit 212 proceeds directly to step S204.

The transmission data acquisition unit 212 determines whether or not data with a priority “medium” exists in the priority queue 221 in step S204 (S204). When data with a priority “medium” exists (S204: YES), the transmission data acquisition unit 212 determines whether or not the current frame matches the value stored in the local node transmission timing information 223 ( S205). If the value matches the value stored in the own node transmission timing information 223 (S205: YES), the transmission data acquisition unit 212 determines that the own node can transmit data, and determines the priority from the priority queue 221. The “medium” data is acquired (S206), the priority is set to “medium” and stored in the transmission data management information 222 (S207), and the process ends.

If there is no data with priority “medium” in step S204, or if the data does not match the value stored in the local node transmission timing information 223 in step S205 (S205: NO), the transmission data acquisition unit 212 performs step S208. Proceed to

In step S208, the transmission data acquisition unit 212 confirms whether or not data with a priority “low” exists in the priority queue 221 (S208). When data with a priority “low” exists (S208: YES), the transmission data acquisition unit 212 acquires data with a priority “low” from the priority queue 221 (S209), and sets the priority to “low”. The data is set and stored in the transmission data management information 222 (S210), and the process ends.

If there is no data with a priority “low” in step S208 (S208: NO), the transmission data acquisition unit ends the process.

Through the above processing, when data to be transmitted in the current frame exists in the priority queue 221, the data is stored in the transmission data management information 222. The data stored in the transmission data management information 222 is in a state of waiting for transmission in the frame. That is, the preparation for transmitting data within the frame is completed.

FIG. 16 is an example of a flowchart showing processing of the transmission data acquisition unit 312 in the gateway 101A.

The transmission data acquisition unit 312 determines whether or not data with a priority “high” exists in the priority queue 321 (S301). When data with a priority “high” exists (S301: YES), the transmission data acquisition unit 312 acquires data with a priority “high” from the priority queue 231 (S302). Then, the transmission data acquisition unit 312 refers to the all-node transmission timing information 323 and determines whether or not the rank of the node assigned to the current frame is an even number (S303).

If the rank of the node assigned to the current frame is not an even number (S303: NO), the transmission data acquisition unit 312 proceeds to step S305.

When the rank of the node assigned to the current frame is an even number (S303: YES), the transmission data acquisition unit 312 sets the acquired data to the transmission data management information 322 with the priority set to “high”. Store. Further, the transmission data acquisition unit 312 changes the time slot waiting number of the stored data to “1” (S304), and proceeds to step S305. That is, the stored data is transmitted not in the current time slot but in the next time slot. As a result, it is possible to prevent interference of data having a high priority.

The processing of steps S305 to S311 is almost the same as the processing of steps S204 to S210 shown in FIG.

FIG. 17 is an example of a flowchart showing a transmission process of the transmission unit 213 (313).

The transmission unit 213 (313) acquires data from the transmission data management information 222 (322) (S401). Next, the transmission unit 213 (313) generates packet data from the acquired data, the transmission direction of the data, the node information 224 (324), and the like (S402). Next, the transmission unit 213 (313) transmits the generated packet data by wireless communication (S403). Next, the transmission unit 213 (313) changes the target priority flag of the reception flag information 225 (325) to “FALSE” (S404), and ends the processing.

Through the above processing, the data stored in the transmission data management information 222 (322) is transmitted to the next node.

FIG. 18 is an example of a flowchart showing the reception process of the reception unit 214 (314).

When the packet data is received, the transmission / reception control unit 211 (311) analyzes the received packet data (hereinafter also referred to as “received data”) (S501), and whether or not the received data needs to be relayed (transferred). Is determined (S502). For example, the transmission / reception control unit 211 (311) determines whether it is necessary to relay (transfer) the packet data based on the transfer destination address 91 included in the received data. Here, when the transfer destination address 91 does not match the address of the own node, or when the transmission destination address 85 matches the address of the own node, the transmission / reception control unit 211 (311) determines that transfer of the received data is unnecessary. (S502: NO). In this case, the transmission / reception control unit 211 (311) changes the reception flag corresponding to the priority of the reception data to “FALSE” (S503), and if the transfer destination address 91 does not match the address of the own node, the reception data If the transmission destination address 85 matches the address of its own node, the received data is passed to the application processing unit 217 (317), and the processing is terminated.

When the transfer destination address 91 matches the address of the own node, the transmission / reception control unit 211 (311) determines that the received data needs to be transferred (S502: YES), and proceeds to step S504.

In step S504, the transmission / reception control unit 211 (311) generates packet data for transfer based on the received data, and stores the packet data in the transmission data management information 222 (322) (S504).

Next, the transmission / reception control unit 211 (311) determines whether or not data with a priority “medium” exists in the transmission data management information 222 (322) (S505), and if it does not exist (S505: NO), The process ends.

When there is data with priority “medium” in the transmission data management information 222 (322) (S505: YES), the transmission / reception control unit 211 (311) further determines whether the priority of the received data is “high”. Is determined (S506). When the priority of the received data is not “high” (S506: NO), the transmission / reception control unit 211 (311) ends the process.

When the priority of the received data is “high” (S506: YES), the transmission / reception control unit 211 (311) determines whether the transmission direction 95 of the received data is “up” or “down” ( S507).

First, the case where the transmission direction 95 of received data is “downlink” (S507: downlink) will be described.

The transmission / reception control unit 211 (311) determines how the rank 94 (that is, the rank of the transmission source node) included in the received data is related to the rank of the own node (S508). When the rank 94 included in the received data is “lower” or “equivalent” than the rank of the own node (S508: lower or equivalent), the transmission / reception control unit 211 (311) ends the process.

When the rank 94 included in the received data is “higher” than the rank of the own node (S508: higher), the transmission / reception control unit 211 (311) has the priority “medium” of the transmission data management information 222 (322). “1” is added to the time slot waiting number 401 of the data (S509), and the process ends.

Next, the case where the transmission direction of the received data is “uplink” (S507: uplink) will be described.

The transmission / reception control unit 211 (311) determines how the rank 94 (that is, the rank of the transmission source node) included in the received data is related to the rank of the own node (S510). When the rank 94 included in the received data is “higher” than the rank of the own node (S510: higher), the transmission / reception control unit 211 (311) ends the process.

When the rank 94 included in the received data is “equivalent” to the rank of the own node (S510: peer), the transmission / reception control unit 211 (311) is similar to the above-described step S509 in the transmission data management information 222 (322). “1” is added to the number of time slot waits for the data with the priority “medium” (S509), and the process is terminated.

When the rank 94 included in the received data is “lower” than the rank of the own node (S510: lower), the transmission / reception control unit 211 (311) has the priority “medium” of the transmission data management information 222 (322). “2” is added to the time slot waiting number of data (S511), and the process is terminated.

Through the above processing, relays (transfers) with high priority and medium priority are appropriately controlled. For example, when it is necessary to relay received data with a high priority, if transmission data with a priority “medium” is stored in the transmission data management information 222 (322), the transmission timing of this transmission data Delay. As a result, received data with a high priority can be relayed preferentially.

In addition, when it is not necessary to relay the received data, it is possible to suppress the reception of data having the same priority as the received data within the current frame. As a result, reception of data transmitted from the adjacent node can be suppressed, and unnecessary time slot waiting time can be reduced.

Next, an example where the wireless multi-hop network system operates based on the method described above will be described.

FIG. 19 shows an example of the operation of each node when data with a high priority is transmitted from the node A to the node e during the frame execution in the node c.

In FIG. 19, the horizontal axis indicates the time transition of the time slot included in the frame of the node c. The vertical axis shows the operation of each node. The hatched divided time indicates that the wireless communication channel corresponding to the priority “high” is tuned. The mottled splitting time indicates that the wireless communication channel corresponding to the priority “medium” is tuned. The white division time indicates that the wireless communication channel with the priority “low” is tuned. The slash of the division time indicates that the priority data is not transmitted / received in the frame. The same applies to FIGS. 20 to 22 below.

In the first time slot 601, the node A transmits data of the priority “high” to the node a (S11). Similarly, in the first time slot 601, the node c transmits data of priority “medium” to the node b (S12). At this time, the data with the medium priority transmitted from the node c is received by the adjacent nodes d and e (R11, R12). However, the node d and the node e determine that relaying is not necessary based on the transfer destination address 91 of the data, and change the priority flag “medium” in the reception flag information 225 to “FALSE”.

Suppose that node A and node c do not process data with the same priority as that processed once in the same frame. Therefore, the node A changes the flag of the priority “high” in the reception flag information 325 to “FALSE”. The node c changes the priority flags “high” and “medium” in the reception flag information 225 to “FALSE”.

In the second time slot 602, the node a transfers the data of the priority “high” received from the node A to the node b (S13). After that, the node a changes the flag of the priority “high” in the reception flag information 225 to “FALSE” in the same manner as described above. Similarly, in the second time slot 602, the node b should transfer the data of the priority “medium” received from the node c and stored in the transmission data management information 222 to the node a. No transfer is made this time (S14). This is because the node “b” first receives data of the priority “high” from the node “a” (S13). Therefore, the node b adds “1” to the time slot waiting number 401 of the data of the priority “medium” stored in the transmission data management information 222 after receiving the data of the priority “high”.

In the third time slot 603, the node b stores the data of the priority “high” and the data of the priority “medium” in the transmission data management information 222. In this case, in the third time slot 603, the node “b” first transfers the data with the priority “high”, which is the smaller number of time slot standbys 401 (S15, S16). After the transfer, the node b changes the flag of the priority “high” in the reception flag information 222 to “FALSE”.

In the fourth time slot 604, the node c transfers the data with the priority “high” to the node e (S17). As a result, the data with high priority reaches the transmission destination node e. The node c and the node e change the priority “high” flag of the reception flag information 225 to “FALSE”. Further, the node d adjacent to the node c receives the high priority data transferred from the node c (R13), but determines that the received data is not addressed to the own node and discards the received data. To do. Further, the node d determines that the data having the high priority in the current frame is irrelevant to the own node, and changes the flag having the high priority in the reception flag information 225 to “FALSE”.

Here, the node b is located within the reach of the radio signal transmitted from the node c (R14). However, since the node “b” has already set the “high” priority flag of the reception flag information 225 to “FALSE”, the node “b” does not react to the above-described high priority data transferred from the node c to the node e. Thereby, in the same fourth time slot, the node b can transfer the data of the priority “medium” to the node a (S18).

In the fifth time slot 605, the node “a” transfers the data of the priority “medium” received from the node “b” to the node A (S19). As a result, data with the priority “medium” also reaches the transmission destination node.

In the sixth time slot, since there is no data to be transmitted / received with the priority “high” or “medium”, basically all the nodes are in a standby state.

As described above, high priority data can be transmitted and transferred with priority. That is, data with a high priority can be made to reach the destination node in a time slot corresponding to the number of hops from the source node to the destination node.

In addition, it is possible to cause the data with the priority “medium” to reach the destination node in the time slot of the number of times “2” added to the number of hops from the source node to the destination node.

FIG. 20 shows an example of the operation of each node when data having a high priority is transmitted from the node e to the node A during frame execution at the node d. FIG. 20 shows an example in which the node e that has received the high priority data in FIG. 19 returns the response data.

In the first time slot, the node e transmits data of the priority “high” to the node c (S21). After the transmission, the node e changes the priority flag of the reception flag information 225 to “FALSE”.

Since the node d adjacent to the node e is executing the frame assigned to the own node, the node d wants to transmit the data with the medium priority stored in the transmission data management information 222. However, the node d first receives the high priority data transmitted from the node e (R21). Therefore, the node d determines that the received data of the priority “high” is the data transmitted in the upstream direction from the node e of rank 4 that is the same as that of the node d. “1” is added to the time slot waiting number 401. That is, the node d sees off transmission of data with the priority “medium” for one time slot (S22).

Further, the node d determines that the data of the priority “high” transmitted from the node e is not related to the own node in the current frame, and sets the flag of the priority “high” in the reception flag information 225 to “ Change to "FALSE".

In the second time slot, the node c transfers the high priority data received from the node e to the node b (S23). After the transfer, the node c changes the flag of the priority “high” in the reception flag information 225 to “FALSE”.

Similarly, secondly, in the time slot, the node d confirms the time slot waiting number 401 of the data with the priority “medium” stored in the transmission data management information 222. However, the time slot waiting number 401 of the data with the priority “medium” is not “0” yet because “1” is added in the above. Therefore, the node d subtracts “1” from the time slot waiting number 401 of the data with the priority “medium”, and does not transmit this data in the current second time slot (S24).

In the third time slot, the node b transfers the high priority data received from the node c to the node a (S25). After the transmission, the node b changes the flag of the priority “high” in the reception flag information 225 to “FALSE”.

Since the time slot waiting number 401 of the data with the priority “medium” is “0”, the node d transmits the data with the priority “medium” to the node c (S26). After the transmission, the node d changes the flag of the priority “medium” in the reception flag information 225 to “FALSE”.

Similarly, the node e adjacent to the node d in the third time slot receives the data of the priority “medium” transmitted from the node d (R22), but discards the data after completion of reception because it is not addressed to its own node. The flag of the priority “medium” in the reception flag information 225 is changed to “FALSE”.

In the fourth time slot, the node a transfers the data of the priority “high” received from the node b to the node A (S27). As a result, data with high priority reaches the transmission destination node. After the transfer, the node a and the node A respectively change the priority flag “high” in the

reception flag information

225 and 325 to “FALSE”.

Similarly, in the fourth time slot, the node c transfers the data of the priority “medium” received from the node d to the node b (S28). After the transfer, the node c changes the flag of the priority “medium” in the reception flag information 225 to “FALSE”.

In the fifth time slot, the node b transfers the data of the priority “medium” received from the node c to the node a (S29). After the transfer, the node b changes the flag of the priority “medium” in the reception flag information 225 to “FALSE”.

In the sixth time slot, the node a transfers the data of the priority “medium” received from the node b to the node A (S30). As a result, data with the priority “medium” reaches the destination node.

As described above, when the data with the priority “high” and the priority “medium” are transferred in the same upstream direction, the data with the priority “high” is transferred with priority. That is, data with high priority can be reached in a time slot corresponding to the number of hops from the transmission source node to the transmission destination node.

This also makes it possible to suppress interference between data with a priority “medium” and data with a priority “high”. That is, data with a priority of “medium” can be reached in the time slot time obtained by adding “2” to the number of hops from the transmission source node to the transmission destination node.

FIG. 21 shows an example of the operation of each node when data of priority “high” is transmitted from the node e to the node A when the frame of the node f is executed. FIG. 21 shows an example in which the node e that has received the high priority data in FIG. 19 returns the response data and receives the high priority data from the lower rank nodes. .

In the first time slot, the node e transmits the data of the priority “high” to the node c (S31). After the transmission, the node e changes the priority flag of the reception flag information 225 to “FALSE”.

Since node f is executing a frame assigned to itself, it wants to transmit data with a medium priority stored in the transmission data management information 222. However, the node f first receives the high priority packet transmitted from the node e (R31). Therefore, the node f determines that the received high priority data is data transmitted from the node e of the rank 4 lower than the own node in the uplink direction, and has the medium priority. “2” is added to the data time slot waiting number 401. In other words, the node f sees transmission of data with the priority “medium” for two time slots (S32).

Further, the node f determines that the data of the priority “high” transmitted from the node e is not related to the own node in the current frame, and sets the flag of the priority “high” in the reception flag information 225 to “ Change to "FALSE".

In the second time slot 602, the node c transfers the high priority data received from the node e to the node b (S33). After the transfer, the node c changes the flag of the priority “high” in the reception flag information 225 to “FALSE”.

Similarly, in the second time slot, the node f confirms the time slot waiting number 401 of the data with the priority “medium” stored in the transmission data management information 222. However, the time slot waiting number 401 of the data with the priority “medium” is not yet “0” because “2” is added in the above. Therefore, the node d subtracts “1” from the time slot waiting number 401 of the data with the priority “medium”, and does not transmit this data in the current second time slot 602 (S34).

In the third time slot 603, the node b transfers the high priority data received from the node c to the node a (S35). After the transfer, the node b changes the flag of the priority “high” in the reception flag information 225 to “FALSE”.

Similarly, in the third time slot 603, the node f confirms the time slot waiting number 401 of the data with the priority “medium” stored in the transmission data management information 222. However, the time slot waiting number 401 of the data of the priority “medium” is not “0” yet because “2” is added in the above. Therefore, the node d subtracts “1” from the time slot waiting number of the data with the priority “medium”, and does not transmit this data in the current second time slot (S36).

In the fourth time slot 604, the node a transfers the data of the priority “high” received from the node b to the node A (S37). As a result, data with high priority reaches the transmission destination node. After the transfer, the node a and the node A respectively change the priority flag “high” in the

reception flag information

225 and 325 to “FALSE”.

Similarly, in the fourth time slot 604, since the time slot waiting number 401 of the data with the priority “medium” is “0”, the node f transmits the data with the priority “medium” to the node b ( S38). After the transmission, the node f changes the flag of the priority “medium” in the reception flag information 225 to “FALSE”.

Similarly, the node e adjacent to the node f in the fourth time slot 604 receives the medium priority data transmitted from the node f (R32), but discards the data after the reception is completed because it is not addressed to the own node. Then, the priority “medium” flag of the reception flag information 225 is changed to “FALSE”.

Since the fifth time slot 605 and the sixth time slot 606 are the same as those in FIG. 20, the description thereof is omitted (S39, S40).

As described above, this is a case where data of priority “high” and priority “medium” is transferred in the uplink direction, and when data of priority “high” is received from a lower rank node. However, data with a high priority is preferentially transferred. That is, data with high priority can be reached in a time slot corresponding to the number of hops from the transmission source node to the transmission destination node.

This also makes it possible to suppress interference between data with a priority “medium” and data with a priority “high”. That is, the data with the priority “medium” can be reached in the time slot in which “3” is added to the number of hops from the transmission source node to the transmission destination node.

FIG. 22 shows an example of the operation of each node when priority “high” data is transmitted from the node A to the node h when the frame of the node d is executed.

In the first time slot 601, the node A holds data with a priority “high”. However, since the frame assigned to the rank d node d, which is an even number, is being executed this time, the node A waits for transmission of the data with the high priority (S41). That is, when the node A acquires the data of the priority “high” from the priority queue 321 and stores it in the transmission data management information 222, as shown in step S304 of FIG. Is changed to “1”.

Since node d is executing a frame of its own node, data of priority “medium” is transmitted to node c (S42). After the transmission, the node d changes the flag of the priority “medium” in the reception flag information 225 to “FALSE”.

In the second time slot 602, since the time slot waiting number 401 of the data with the priority “high” is “0”, the node A transmits the data with the priority “high” to the node a (S43). After the transmission, the node A changes the flag of the priority “high” in the reception flag information 225 to “FALSE”.

In the same second time slot, the node c transfers the data of the priority “medium” received from the node d to the node b (S44). After the transfer, the node c changes the flag of the priority “medium” in the reception flag information 225 to “FALSE”.

In the third time slot, the node a transfers the data of the priority “high” received from the node A to the node h (S45). As a result, the data with high priority reaches the transmission destination node. After the transfer, the node a changes the flag of the priority “high” in the reception flag information 225 to “FALSE”.

In the same third time slot, the node b wants to transmit the packet with the medium priority stored in the transmission data management information 222. However, the node b first receives the data with the priority “high” from the node a. Therefore, the node b determines that the received data with the high priority is data transmitted in the downstream direction from the node A of rank 0 higher than the own node, and has the medium priority. “1” is added to the number of timeslot waiting for data. That is, the node b defers transmission of data with the priority “medium” for one time slot (S46). Further, the node “b” determines that the data of the priority “high” transmitted from the node “a” is not related to the own node in the current frame, and sets the flag of the priority “high” in the reception flag information 225 to “ Change to "FALSE".

In the fourth time slot 604, the node b confirms the time slot waiting number 401 of the data with the priority “medium” stored in the transmission data management information 222. However, the time slot waiting number 401 of the data with the priority “medium” is not “0” yet because “1” is added in the above. Therefore, the node d subtracts “1” from the time slot waiting number 401 of the data with the priority “medium”, and does not transmit this data in the current fourth time slot 604 (S47).

In the fifth time slot 605, the node b transmits the data with the priority “medium” to the node a because the time slot waiting number 401 of the data with the priority “medium” is “0” (S48). ). After the transmission, the node b changes the flag of the priority “medium” in the reception flag information 225 to “FALSE”.

In the sixth time slot 606, the node a transfers the data of the priority “medium” received from the node b to the node A (S49). As a result, data with the priority “medium” reaches the destination node.

When data of priority “high” is transmitted from the gateway 101A and data of priority “medium” is transmitted from an even-ranked node, a hidden terminal problem in wireless communication occurs. Data of priority “medium” is lost. However, as described above, the transmission of data having a high priority from the gateway 101A is shifted by one time slot to prevent the hidden terminal problem in the wireless communication, and the medium priority from the node having an odd rank. Similarly to the case where the data of “5” is transmitted, in the five time slots in one frame, both the data of the priority “high” and the priority “medium” can be transferred.

According to the first embodiment, a plurality of data having different priorities can be transmitted and received within one frame. Furthermore, data with high priority can be reached at the destination node in a shorter time. That is, it is possible to reduce the number of times high priority data is kept waiting in the time slot and to reach the transmission destination node with a smaller number of time slots.

In the wireless network 100 shown in FIG. 1, it is desirable to arrange nodes having two or more ranks away from each other so as not to receive radio waves. However, after building the wireless network 100 due to, for example, movement of obstacles, flow of people, or changes in weather, the radio wave environment changes, and nodes that are separated by two or more ranks transmit radio waves to each other. It is also possible to receive it. In the second embodiment, the configuration and processing in such a case will be described.

FIG. 23 shows an example of the configuration of a wireless multi-hop network system 1000 in which some obstacles exist according to the second embodiment.

The wireless network 1000 includes a gateway 1001A (node A), a wireless communication device 1002a (node a), and a wireless communication device 1002b (node b). Initially, it is assumed that an obstacle 1003 exists between the gateway 1001A and the wireless communication device 1002b, and no radio wave arrives between the gateway 1001A and the wireless communication device 1002b. That is, initially, it is assumed that the gateway 100A and the wireless communication device 1002a are wirelessly connected, and the wireless communication device 1002a and the wireless communication device 1002b are wirelessly connected.

Here, for example, when the obstacle 1003 is eliminated, the radio wave arrives between the gateway 1001A and the wireless communication device 1002b.

FIG. 24 shows an example of a time slot related to transmission / reception of data with high priority. In the second embodiment, the super frame 50, the frame 51, and the time slot 52 are the same as those in the first embodiment. However, the second embodiment is different from the first embodiment in the data transmission / reception process in the time slot. In FIG. 24, a process of transmitting / receiving data with high priority will be described as an example.

FIG. 24 (a) shows a time slot 1100a in the case of transmitting data with high priority.

When the start timing of the time slot 1100a is reached, the node first switches to the wireless communication channel with the priority “high” at the switching time 60a. Next, the node transmits packet data including the destination address (hereinafter referred to as “address packet”) at time 1101, and after waiting for a predetermined time 1102, transmits data of high priority. Hereinafter, the data transmitted after the transmission of the address packet is referred to as a “data packet”. Details of the address packet 1300 and the data packet 1400 will be described later (see FIG. 25).

After that, the node switches to the wireless communication channel with the priority “low” at the switching time 60 c and executes processing related to transmission / reception of the data with the priority “low” during the division time 63.

FIG. 24 (b) shows a time slot 1100b in the case of receiving data with the priority “high” in FIG. 24 (a).

When the start timing of the time slot 1100b is reached, the node first switches to the wireless communication channel with the priority “high” at the switching time 60a. Next, the node waits for reception of the address packet 1300 at time 1201. Here, when the address packet 1300 is received, and the transfer destination address 91 included in the address packet 1300 is addressed to the own node, data of high priority is received after waiting for a predetermined time 1202. .

FIG. 24C shows the time slot 110c when the address packet 1300 is received in the above, but the forwarding address 91 included in the address packet is not addressed to the own node.

When the start timing of the time slot 1100c is reached, the node first switches to the wireless communication channel with the priority “high” at the switching time 60a. Next, the node waits for reception of the address packet 1300 at time 1201. Here, when the address packet 1300 is received but the transfer destination address 91 included in the address packet 1300 is not addressed to the own node, the priority “medium” is set at the switching time 60b after waiting for the predetermined time 1202. Switch to the wireless communication channel. Thereafter, as in the case of the first embodiment, processing related to transmission / reception of data with priority “medium” and “low” is executed.

24A to 24C described the case where the priority is “high”. Similarly, in the case where the priority is “medium” as well, first, after waiting for transmission or reception of the address packet 1300, a predetermined time After that, the data packet 1400 having the medium priority is transmitted or received.

Thereby, it is possible to prevent only the node at the destination address from receiving the data packet 1400 and the node other than the destination address from which the radio wave arrives from receiving the data packet 1400 in vain.

FIG. 25 shows an example of the data structure of the address packet and the data packet.

FIG. 25A shows an example of the data structure of the address packet 1300. The address packet 1300 includes a header 1301 and inspection data 83.

The header 1301 includes a transfer destination address 91, a transfer source address 92, a packet length 93, and a packet type 1302. The description of the transfer destination address 91, the transfer source address 92, and the packet length 2413 is the same as that of the packet data 80 shown in FIG. Similarly, the description of the inspection data 83 is also omitted.

The packet type 1302 stores a value for identifying whether the packet is an address packet or a data packet. For example, the packet type 1302 of the address packet is determined in advance as “0” and the packet type 1302 of the data packet is determined as “1”.

FIG. 25 (b) shows an example of the data structure of the data packet 1400.

Similarly to the packet data 80 shown in FIG. 13 of the first embodiment, the data packet 1400 includes a header 1401, a payload 82, and inspection data 83.

Here, the difference from the packet data 80 shown in FIG. 13 of the first embodiment is that a packet type 1302 is added to the header 1401.

FIG. 26 illustrates an example of a flowchart of transmission processing of the transmission unit according to the second embodiment. The transmission process illustrated in FIG. 26 corresponds to the transmission process illustrated in FIG. 17 in the first embodiment.

The transmission unit acquires data to be transmitted from the transmission data management information 222 (322) (S701). Next, the transmission unit generates an address packet 1300 (S702). Next, the transmission unit wirelessly transmits the generated address packet 1300 (S703). Next, the transmission unit waits for a predetermined time (S704). Next, the transmission unit generates a data packet 1400 (S705). Next, the transmission unit wirelessly transmits the generated data packet 1400 (S706). Finally, the transmission unit changes the reception flag corresponding to the priority of the transmitted data to “FALSE” (S707), and ends the process.

That is, the transmission unit according to the second embodiment first transmits an address packet 1300 and then transmits a data packet 1400 corresponding to the packet data 80 of the first embodiment, as compared with the first embodiment.

FIG. 27 illustrates an example of a flowchart of the reception process of the reception unit according to the second embodiment. The reception process illustrated in FIG. 27 corresponds to the reception process illustrated in FIG. 18 in the first embodiment.

When receiving the address packet 1300, the receiving unit analyzes the address packet 1300 (S801), and determines whether or not the transfer destination address 91 is addressed to the own node (S802).

If the forwarding address 91 is not addressed to the own node (S802: NO), the receiving unit waits for a predetermined time (S805), and then proceeds to step S111 shown in FIG.

When the forwarding address 91 is addressed to the own node (S802: YES), the receiving unit waits for a predetermined time (S803), receives the data packet (S804), and proceeds to step S502 in FIG.

As a result, even when the radio wave reaches a node whose rank is two or more, as shown in the first embodiment, data with high priority is reduced in a shorter time (small number of time slots). Thus, the destination node can be reached.

The embodiments of the present invention described above are examples for explaining the present invention, and are not intended to limit the scope of the present invention only to those embodiments. Those skilled in the art can implement the present invention in various other modes without departing from the gist of the present invention.

100 ... Wireless multi-hop network system 101A ... Gateway 102 ... Wireless communication device

Claims

A wireless communication device constituting a tree-shaped wireless multi-hop network,
A synchronization unit that synchronizes timing with respect to other wireless communication devices;
A transmission data management unit for managing data to be transmitted to another wireless communication device in association with the priority of the data;
A transmission unit that transmits predetermined data stored in the transmission data management unit to another wireless communication device;
A receiving unit for receiving data transmitted from another wireless communication device;
At a predetermined timing, a transmission / reception control unit that switches to a wireless communication channel associated with the priority of the data and controls transmission or reception of the data of the priority,
A wireless communication device.
The transmission / reception control unit includes:
At the predetermined timing, switching to a wireless communication channel corresponding to a certain priority, predetermined reception time, let the reception unit wait to receive data,
A) If no data is received within the waiting time, switch to a wireless communication channel corresponding to a priority lower than the certain priority,
B) When reception of data is started within the waiting time, the same wireless communication channel is maintained until reception of the data that has started reception is completed, and thereafter, a priority lower than the certain priority is supported. The wireless communication apparatus according to claim 1, wherein the wireless communication channel is switched to a wireless communication channel.
The transmission / reception control unit includes:
After switching to a wireless communication channel corresponding to a priority lower than the certain priority, the reception unit waits for reception of data for a predetermined standby time, and performs the determination according to A) and B) The wireless communication apparatus according to claim 2, wherein the wireless communication device is repeated until a time slot that is a predetermined time is completed.
The transmission / reception control unit includes:
Specify data to be transmitted from the transmission data management unit, and switch to a wireless communication channel corresponding to the priority of the data to be transmitted at a predetermined timing in a time slot in which the wireless communication apparatus can transmit data. The wireless communication apparatus according to claim 2, wherein the data to be transmitted is transmitted to the transmission unit.
The transmission / reception control unit includes:
If the reception of data having a higher priority than the priority of the data to be transmitted is started within the waiting time before the timing to transmit the data to be transmitted, the time slot in which the data to be transmitted can be transmitted The wireless communication device according to claim 4, wherein the wireless communication device is delayed by a certain number of time slots.
The data to be transmitted / received includes a rank indicating the hierarchy in the tree shape of the node that is the transmission source of the data, and a transmission direction indicating whether the data is transmitted in the up or down direction of the tree shape. Included,
The transmission / reception control unit includes:
6. The number of time slots to be delayed is determined based on the transmission direction included in the received data, and a positional relationship between a rank included in the received data and a rank of the wireless communication device. Wireless communication device.
The transmission / reception control unit includes:
When the transmission direction included in the received data is downlink and the rank included in the received data is higher than the rank of its own wireless communication device, the number of the time slots is delayed by one,
When the transmission direction included in the received data is uplink and the rank included in the received data is the same as the rank of its own wireless communication device, the number of time slots is delayed by one,
The number of the time slots is delayed by two when the transmission direction included in the received data is uplink and the rank included in the received data is lower than the rank of the own wireless communication device. The wireless communication device described.
The transmission / reception control unit includes:
When switching to a wireless communication channel corresponding to the lowest priority at the predetermined timing, after performing carrier sense on the wireless communication channel, the transmission unit transmits data corresponding to the lowest priority. Item 8. The wireless communication device according to any one of Items 3 to 7.
The transmission / reception control unit includes:
When transmitting the data to be transmitted, first transmitting the preceding data including the transfer destination address of the data to be transmitted, then transmitting the data to be transmitted;
When waiting to receive data,
In A), when the preceding data is not received within the waiting time, or when the transfer destination address included in the preceding data does not indicate its own wireless communication device, Switch to a wireless communication channel that supports a priority lower than the priority,
In B), if the preceding data is received within the waiting time and the transfer destination address included in the preceding data indicates the own wireless communication device, the same wireless communication channel is maintained. The wireless communication apparatus according to claim 2, wherein the data to be transmitted thereafter is received and then switched to a wireless communication channel corresponding to a priority lower than the certain priority.
A tree-shaped wireless multi-hop network system configured by a plurality of wireless communication devices, each of the plurality of wireless communication devices,
A time synchronization unit that synchronizes timing related to time with other wireless communication devices;
A transmission data management unit for managing data to be transmitted to another wireless communication device in association with the priority of the data;
A transmission unit that transmits predetermined data stored in the transmission data management unit to another wireless communication device;
A receiving unit for receiving data transmitted from another wireless communication device;
At a predetermined timing, a transmission / reception control unit that switches to a wireless communication channel associated with the priority of the data and controls transmission or reception of the data of the priority,
A wireless multi-hop network system.