JP6508594B2 - Communication node, communication method and wireless communication system - Google Patents

Description

  The present invention relates to a communication node, a communication method, and a wireless communication system, and more particularly, to a communication node performing multi-hop communication, a communication method, and a wireless communication system.

  Conventionally, a network system for performing multi-hop wireless communication between a base station node device and a plurality of child node devices has been proposed (for example, see Patent Document 1).

JP, 2013-74355, A

  Generally, in a communication network, when data transmitted by one node is received by another node, the receiving node transmits an ACK to the transmitting node. Therefore, the node on the transmitting side controls the wireless transmission / reception unit to a state in which the ACK can be received until the predetermined reception waiting time elapses after transmitting the data, and if the ACK can not be received during this time You are retransmitting data. Therefore, if the data transmitted by one node is not received by another node, the data is not retransmitted unless the reception waiting time has elapsed since the data transmission time. Therefore, when data retransmission occurs at each node from the source node to the final destination node, it takes time for the data to reach the final destination node.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a communication node, a communication method, and a wireless communication system capable of shortening the time required for data to reach the final destination node.

Communication node Bei Eteiru and a controller wireless communication section that performs wireless communication. The control unit, when no communication path from the local node to the final destination node is established, transmits data to the other nodes in the broadcast, the destination is communication route from the own node to the final destination node is established in a state where the node is determined, it controls the wireless communication unit to transmit the data in unicast to the destination node. Further, the control unit controls the wireless communication unit to receive an ACK from another node or the determined destination node. The data includes first measurement data and second measurement data measured after a predetermined time has elapsed since the first measurement data was measured. Then, the control unit, from any of the nodes that received the first measurement data transmitted by broadcast, based on the final destination information, information indicating that the communication path from the own node to the final destination node has been established. The transmission destination node is determined by receiving an ACK including the first measurement data in a broadcast and before the first time elapses, and the second measurement data next time When transmitting, the second measurement data is transmitted by unicast to the destination node, and the second measurement data is transmitted by unicast, and then a second time shorter than the first time If the transmission of the second measurement data to the destination node is unsuccessful because the ACK can not be received from the destination node until the elapse of Characterized in that the measured data is configured to control the wireless communication unit to retransmit.

Communication method includes the step of transmitting the data by broadcast to the wireless communication unit when no communication path from the local node to the final destination node is established, the communication route from the own node to the final destination node is established in a state where the cage destination node is determined, which of the steps of transmitting the data in unicast to the destination node in the wireless communication unit, the node which received the data sent by the broadcast From that point on, based on the final destination information, an ACK indicating that the communication path from the own node to the final destination node has been established is received between the transmission of the data by broadcast and the elapse of the first time. To the node of the transmission destination determined by the above, and for the node of the transmission destination determined when transmitting the data next time In the step of transmitting the data by unicast, and after the data is transmitted by unicast, the ACK can not be received during a time until a second time shorter than the first time elapses, the transmission destination Controlling the wireless communication unit to retransmit the data if the transmission of the data to the node fails .

Radio communications system includes a source node having a wireless communication function, the final destination node and, a plurality of relay having a function of relaying radio communication between the source node and the final destination node having a wireless communication function And a node. The transmission source node and the relay node transmit the data to other nodes by broadcast in a state where the communication path of data from the own node to the final destination node is not established. Also, the source node and the relay node, to the node which decided destination by a communication route is established, and transmits the data in unicast, from the other node or determined the destination node Receive an ACK. The data includes the first measurement data and the second measurement data measured after a predetermined time has elapsed since the first measurement data was measured. The transmission source node and the relay node establish the communication path from the own node to the final destination node based on the final destination information from any of the nodes having received the first measurement data transmitted by broadcast. A transmission destination node is determined by receiving an ACK to the effect that the first measurement data has been transmitted by broadcast and before the first time has elapsed, and the second measurement data is transmitted next time When the second measurement data is transmitted by unicast to the destination node and the second measurement data is transmitted by unicast, a second time shorter than the first time elapses until that, if it fails to transmit the second measurement data to the destination node can not receive the ACK, it retransmits the second measurement data And wherein the door.

  According to the communication node, the communication method, and the wireless communication system of the present invention, when data is transmitted by unicast, the reception waiting time in which an ACK can be received can be shortened compared to the case where data is transmitted by broadcast. doing. Therefore, when data is transmitted by unicast, when it is not possible to receive ACK and retransmits the data, the time taken to retransmit the data is reduced, so from the source node to the final destination node It can reduce the time it takes for data to arrive.

It is explanatory drawing of the communication procedure by the radio | wireless communications system of embodiment. It is a block diagram of the child machine of an embodiment. It is a block diagram of a parent machine of an embodiment. It is a block diagram of a repeater of an embodiment. It is explanatory drawing of another communication procedure by the radio | wireless communications system of embodiment. It is explanatory drawing of another communication procedure by the radio | wireless communications system of embodiment. It is a time chart explaining operation of a radio communications system of an embodiment. It is a time chart explaining another operation of the radio communications system of an embodiment. It is a time chart explaining another operation of the radio communications system of an embodiment. It is a time chart explaining another operation of the radio communications system of an embodiment.

  Embodiments of a communication node and a wireless communication system according to the present invention will be described based on the drawings. However, the configuration described below is merely an example of the present invention. The present invention is not limited to the following embodiments, and various modifications can be made according to the design and the like without departing from the technical concept of the present invention.

  FIG. 1 shows a schematic configuration of a wireless communication system according to the present embodiment. The wireless communication system according to the present embodiment includes, as a communication node, a plurality of slaves (transmission source nodes) 10 that are data transmission sources, a plurality of masters (final destination nodes) 20 that are final transmission destinations of data, The relay unit (relay node) 30 is provided (for example, three in FIG. 1). In the wireless communication system of the present embodiment, the number of handsets 10 and the number of base units 20 is one, but the number of handsets 10 and the number of base units 20 is not limited to one, and a plurality may be provided. In addition, although the number of relays 30 is three in the wireless communication system of the present embodiment, the number of relays 30 can be appropriately changed according to the number of slaves 10, the installation location, and the like.

  The slave unit 10, the master unit 20, and the relay unit 30 each have a wireless communication unit that does not require a wireless license (for example, a specified low-power wireless module, a wireless communication unit compliant with the IEEE 802.15.1 standard, IEEE 802.15. And a wireless communication unit conforming to the 4 standards. Here, if the handset 10 and the base unit 20 are within the communication range of each other and the communication environment between the handset 10 and the base unit 20 is good, wireless communication between the handset 10 and the base unit 20 is possible. Communication takes place directly. However, if the slave 10 and the master 20 are separated so that they can not directly communicate with each other, or if they can communicate, the communication environment is not good, the relay phone 30 may be used between the slave 10 and the master 20. Wireless communication is performed. Therefore, the plurality of relays 30 are arranged such that other adjacent relays 30 are present within the communication range so as to be able to relay the wireless communication between the slave 10 and the master 20, A relay communication network is constructed by 10, a master unit 20 and a plurality of relay units 30. The slave unit 10, the master unit 20, and the plurality of relay units 30 are communication nodes constituting a wireless communication network, and each communication node is an individual node number for identifying an individual node in the wireless communication network. Is granted. In the wireless communication system according to the present embodiment, the node number of the master unit 20 is set to “0”, and the node numbers “1” to “3” are respectively set to each of the three relay units 30. The node number of "11" is set to. In the explanatory views of FIG. 1, FIG. 5 and FIG. 6, the numbers in the square box showing each of the slave unit 10, the master unit 20 and the relay unit 30 are the numbers of the slave unit 10, the master unit 20 and the relay unit 30. The node numbers assigned to each are shown.

  Next, configurations of the slave unit 10, the master unit 20, and the relay unit 30 will be described based on FIGS.

  As shown in FIG. 2, the slave unit 10 includes an MCU (Micro Control Unit) 100, a storage unit 101, a wireless communication unit 102, an antenna 103, a wired communication unit 104, an operation unit 105, and a display unit 106. , A power supply unit 107, and a measurement unit 108. The slave unit 10 wirelessly transmits the data measured by the measurement unit 108 to the master unit 20 at predetermined time intervals.

  The MCU 100 implements a function as a control unit by executing a program stored in the storage unit 101. The program executed by the MCU 100 may be provided through a telecommunication line, or may be stored and provided in a recording medium such as a memory card.

  The wireless communication unit 102 includes, for example, a wireless module conforming to the communication standard of the specified low power wireless, and transmits or receives a wireless signal via the antenna 103. The wireless communication unit 102 also has a function of measuring the received signal strength of the received signal.

  The storage unit 101 includes a ROM, a RAM, and the like. The storage unit 101 may include an electrically rewritable non-volatile memory such as an EEPROM (electrically erasable and programmable read only memory). The storage unit 101 stores a program executed by the MCU 100. The storage unit 101 stores identification information (address or node number) assigned to the child device 10, measurement data by the measurement unit 108, information on communication paths, and the like. In addition, the storage unit 101 stores an ACK reception waiting time and a specified number of times and a maximum number of times of retransmission in the case of retransmitting data. Here, the ACK reception waiting time refers to the time for the wireless communication unit 102 to operate in a state where an ACK can be received after data transmission. In the present embodiment, the storage unit 101 includes, as the ACK reception waiting time, a first time which is a reception waiting time when data is transmitted by broadcast, and a reception waiting time when data is transmitted by unicast. Store two hours and a third time. The second time is a time shorter than the first time, and is set to the maximum time taken by the wireless communication unit 102 to transmit data in unicast to the destination node and to receive an ACK. It should just be. The third time may be set to be longer than the second time and shorter than the first time.

  The wired communication unit 104 is connected to, for example, a device such as a setting device via a communication line, and performs communication by a wired communication method.

  The operation unit 105 is used by the user to set, for example, the lower limit value and the upper limit value of the measurement range by the measurement unit 108, the measurement interval, and the transmission interval of the measurement data. The operation unit 105 is also used for the user to set an ACK reception waiting time, and a specified number of times and a maximum number of times of retransmission when retransmitting data.

  The display unit 106 includes, for example, one or more light emitting diodes, and the MCU 100 controls lighting / extinguishing.

  The power supply unit 107 supplies power necessary for operation to the internal circuit of the slave unit 10 using, for example, a battery as a power supply.

  The measuring unit 108 is, for example, for measuring a temperature, includes a thermistor whose electric resistance changes according to the ambient temperature, and measures the ambient temperature by measuring the resistance value of the thermistor. The measurement target of the measurement unit 108 is not limited to the temperature, and it is sufficient to measure a physical quantity according to the purpose of use or application, such as ambient humidity or illuminance.

  As shown in FIG. 3, the parent device 20 has an MCU 200, a storage unit 201, a wireless communication unit 202, an antenna 203, a wired communication unit 204, an operation unit 205, a display unit 206, and a power supply unit 207. Is equipped.

  The MCU 200 implements the function as the parent device 20 by executing the program stored in the storage unit 201. The program executed by the MCU 200 may be provided through a telecommunication line, or may be stored and provided in a recording medium such as a memory card.

  The wireless communication unit 202 includes, for example, a wireless module conforming to the communication standard of the specified low power wireless, and transmits or receives a wireless signal via the antenna 203. The wireless communication unit 202 also has a function of measuring the received signal strength of the received signal.

  The storage unit 201 includes a ROM, a RAM, and the like. The storage unit 201 may include an electrically rewritable non-volatile memory such as an EEPROM. The storage unit 201 stores a program executed by the MCU 200. The storage unit 201 stores identification information assigned to the parent device 20, measurement data collected from the child device 10, information on communication paths, and the like. In addition, the storage unit 201 stores an ACK reception waiting time when the parent device 20 transmits data as a transmission source, and a specified number of times and a maximum number of retransmissions when data is retransmitted. In the storage unit 201, as a reception waiting time of ACK, a first time which is a reception waiting time when data is transmitted by broadcast, a second time which is a reception waiting time when data is transmitted by unicast, and Three hours are stored. The second time is a time shorter than the first time, and is set to the maximum time taken by the wireless communication unit 202 to transmit data in unicast to the destination node and to receive an ACK. It should just be. The third time may be set to be longer than the second time and shorter than the first time.

  The wired communication unit 204 is connected to, for example, a server via a communication line, and transmits data collected from the slave 10 to the server by a wired communication method.

  The operation unit 205 is used, for example, for the user to set the operation of the parent device 20. The operation unit 205 is also used to set an ACK reception waiting time when the parent device 20 transmits data as a transmission source, and a specified number of times and a maximum number of retransmissions when data is retransmitted.

  The display unit 206 includes, for example, one or more light emitting diodes, and the MCU 200 controls lighting / extinguishing.

  The power supply unit 207 receives supply of power from, for example, a commercial power supply, and supplies power necessary for operation to the internal circuit of the parent device 20.

  The relay unit 30 has a function of relaying wireless communication between the slave unit 10 and the master unit 20. As shown in FIG. 4, the relay unit 30 includes an MCU 300, a storage unit 301, a wireless communication unit 302, an antenna 303, a wired communication unit 304, an operation unit 305, a display unit 306, a power supply unit 307, and the like. Is equipped.

  The MCU 300 implements the function as the relay device 30 by executing the program stored in the storage unit 301. The program executed by the MCU 300 may be provided through a telecommunication line, or may be provided by being stored in a recording medium such as a memory card.

  The storage unit 301 includes a ROM, a RAM, and the like. The storage unit 301 may include an electrically rewritable non-volatile memory such as an EEPROM. The storage unit 301 stores a program that the MCU 300 executes. The storage unit 301 stores identification information assigned to the own device, data received by the wireless communication unit 302, data transmitted by the wireless communication unit 302 in the past, information on communication paths, and the like. In addition, the storage unit 301 stores an ACK reception waiting time, and a specified number of times and a maximum number of times of retransmission when retransmitting data. In the storage unit 301, as a reception waiting time of ACK, a first time which is a reception waiting time when data is transmitted by broadcast, and a second time and a third time which is a reception waiting time when data is transmitted by unicast The time is stored. The second time is a time shorter than the first time, and is set to the maximum time taken by the wireless communication unit 302 to transmit data in unicast to the destination node and to receive an ACK. It should just be. The third time may be set to be longer than the second time and shorter than the first time.

  The wireless communication unit 302 includes, for example, a wireless module conforming to the communication standard of the specified low power wireless, and transmits or receives a wireless signal via the antenna 303. The wireless communication unit 302 also has a function of measuring the received signal strength of the received signal.

  The wired communication unit 304 is connected to, for example, a device such as a setting device via a communication line, and performs communication by a wired communication method.

  The operation unit 305 is used, for example, for the user to set the operation of the relay unit 30. The operation unit 305 is also used by the user to set an ACK reception waiting time, and a specified number of times and a maximum number of times of retransmission when retransmitting data.

  The display unit 306 includes, for example, one or more light emitting diodes, and the MCU 300 controls lighting / extinguishing.

  The power supply unit 307 supplies power necessary for operation to the internal circuit of the relay device 30 using, for example, a battery as a power supply. Since the relay unit 30 uses a battery as a power source, the relay unit 30 can be installed and used at a free place. The power supply unit 307 may receive power supply from a commercial power supply and supply power necessary for operation to the internal circuit of the relay device 30.

  Next, in the wireless communication system of this embodiment, processing for transmitting data (for example, measurement data) from the child device 10 to the parent device 20 in a state where the communication path between the child device 10 and the parent device 20 is not established. Will be described with reference to FIG. 1, FIG. 5 and FIG. Note that separate node numbers are assigned to each of the slave unit 10, the master unit 20, and the plurality of relay units 30, and in the following, the node numbers are used to distinguish and describe the plurality of relay units 30. To explain. For example, the relay unit 30 with the node number “2” is described as the second relay unit 30. Further, arrow lines in FIG. 1, FIG. 5 and FIG. 6 indicate communication between nodes, solid arrow lines indicate data transmission processing, and dotted arrow lines indicate ACK transmission processing.

  A communication procedure in the case where the child device 10 transmits measurement data for the first time in a state where a communication path for transmitting data from the child device 10 to the parent device 20 is not established will be described with reference to FIG.

  The MCU 100 of the slave unit 10 starts from the sleep mode at a predetermined sampling interval (for example, an interval of several seconds to several minutes) and causes the measuring unit 108 to measure the temperature. The MCU 100 stores the measurement data of the measurement unit 108 and the individual sequence numbers assigned to the transmission data, and uses the destination address as the broadcast address, and the source address and the data source address as the address (for example, node number) of the own device. Create transmission data. The MCU 100 controls the wireless communication unit 102 to transmit the created transmission data by broadcast, and the transmission data is wirelessly transmitted from the slave 10 by broadcast (processing T1 in FIG. 1).

  In the example of FIG. 1, three repeaters 30 having node numbers 1 to 3 exist in the communication range of handset 10, and data transmitted from handset 10 is wirelessly transmitted from these three repeaters 30. It is received by the communication unit 302. The MCU 300 of each relay device 30 extracts the measurement data, the sequence number, the destination address (broadcast address), the source address, and the data source address from the received data. Each of the first to third repeaters 30 having received the data from the slave 10 transmits an ACK (acknowledgement) to the slave 10 of the transmission source. Here, when receiving data, the MCU 300 of each relay device 30 sets a wait time until transmitting an ACK to a random time. The MCUs 300 of the first to third repeaters 30 respectively control the wireless communication unit 302 after the elapse of the wait time from the time of data reception to transmit an ACK to the slave unit 10 of the transmission source (the process of FIG. 1) T2). In addition, since the wait time is set to a random time, the possibility that ACKs are simultaneously transmitted from the plurality of relay devices 30 is low, and a communication error due to a data collision is less likely to occur.

  The MCU 100 of the slave unit 10 controls the wireless communication unit 102 so that the wireless communication unit 102 can receive an ACK while a certain reception waiting time elapses from the time of transmitting data by broadcast. . If the MCU 100 of the slave unit 10 can receive the ACK transmitted from any of the relay units 30 after the data transmission, it determines that the data transmission is successful, and before the reception waiting time elapses from the data transmission time. Even in the sleep mode, the power consumption is reduced.

  In the example of FIG. 1, the wait time of the first repeater 30 is shorter than the wait times of the other repeaters 30. Therefore, the first relay device 30 transmits an ACK to the slave device 10 earlier than the other relay devices 30 after the wait time has elapsed. Here, when the wireless communication unit 102 receives an ACK from the first relay device 30, the MCU 100 of the slave device 10 determines that the transmission of the data D1 is successful, and shifts to the sleep mode. Therefore, when the second and third repeaters 30 transmit an ACK to the slave 10, the slave 10 has shifted to the sleep mode, and the slave 10 receives the second and third repeaters 30. I can not receive ACK. Although the handset 10 can not receive ACKs from the second and third relays 30, it can be determined that transmission of the data D1 is successful by receiving the ACK from the first relay 30, so there is a particular problem. There is no. The MCU 100 of the slave unit 10 determines that the data transmission has failed if the wireless communication unit 102 can not receive the ACK during the period from when the data is transmitted to when the reception waiting time elapses. In this case, the MCU 100 of the slave unit 10 may shift to the sleep mode after performing retransmission processing of the data for which transmission failed, or may shift to the sleep mode and transmit the current data together at the next data transmission. You may

  When each relay unit 30 receives data transmitted by broadcast from a lower node, it receives an ACK transmitted from another relay unit 30 for the same data before transmitting an ACK for this data, The relay transmission to the upper node is configured not to be performed. In the example of FIG. 1, since the first relay station 30 first transmits an ACK to the slave 10, only the first relay station 30 relays data. The second and third relays 30 receive the ACK transmitted from the first relay 30 before transmitting the ACK, and therefore only transmit the ACK without performing relay transmission of data. When the second and third repeaters 30 receive the data transmitted from the slave 10 and receive an ACK transmitted from the other repeater 30 to the slave 10 for the same data, Neither relay transmission of data nor transmission of ACK to the slave 10 may be performed. That is, when the relay device 30 receives the data transmitted from the slave device 10, only the relay device 30, which transmitted the first ACK to the slave device 10, transmits the ACK to the slave device 10, and Relay transmission of data to the node may be performed.

  When the MCU 300 of the first relay device 30 receives the data D1 transmitted from the child device 10 in process T1, the MCU 300 of the transmission data received from the child device 10 measures the measurement data, the sequence number, the destination address, the transmission source address, and the data source. Get address Then, the MCU 300 of the first relay device 30, including the measurement data and the sequence number, sets the destination address as the broadcast address, the transmission source address as the own device address, and the data source address as the 11th slave device 10 address. Create transmission data. Then, the MCU 300 of the first relay device 30 controls the wireless communication unit 302 to transmit the transmission data by broadcast when the transmission waiting time has elapsed since the data reception (process T3 in FIG. 1). Here, the transmission waiting time may be a predetermined time set in advance or may be a random time. In addition, the transmission waiting time is preferably set to a time longer than a waiting time from reception of data to transmission of ACK, and data to be relayed and transmitted by the first relay device 30, second and third The possibility of collision with the ACK transmitted from the relay station 30 of the No. 3 is reduced.

  In the example of FIG. 1, since the handset 10 and the base unit 20 and the second relay 30 are present within the communication range of the first relay 30, the broadcast is transmitted from the first relay 30 The data is received by the wireless communication unit 202 of the parent device 20 and the wireless communication unit 302 of the second relay device 30. Since the slave 10 is in the sleep mode after data transmission, the data transmitted from the first relay 30 is not received by the slave 10.

  When the wireless communication unit 202 of the parent device 20 receives the transmission data from the first relay device 30, the MCU 200 of the parent device 20 measures the measurement data, the sequence number, the destination address, the transmission source address, and the data source from the received data. Take out the address. When the MCU 200 of the parent device 20 receives the transmission data from the first relay device 30, the MCU 200 transmits an ACK to which the final destination information is added to the first relay device 30 that is the transmission source without providing a wait time (FIG. 1 Processing T4). The final destination information is information indicating that the communication node of the transmission source is a communication node capable of communicating with the parent device 20, and in the present embodiment, the final destination information is the number of relay hops to the parent device 20. Therefore, the base unit 20 transmits an ACK added with “1” of data, which is the number of relay hops to the base unit 20, to the first relay station 30. When the first to third repeaters 30 transmit an ACK in process T2, the first to third repeaters 30 do not receive the final destination information from the upper node, so the first to third repeaters 30 do not receive the final destination information. The final destination information is not added to the ACK transmitted from the relay device 30. In other words, data indicating that the number of relay hops is zero is added to the ACKs transmitted from the first to third relay stations 30 in process T2. In the present embodiment, if the slave 10 and the relay 30 receive the ACK to which the final destination information is added from the upper node (the master 20 or the relay 30), the slave 10 and the relay 30 transmit the ACK to which the final destination information is added. The higher node is determined as the destination node.

  Further, when the wireless communication unit 302 of the second relay device 30 receives the transmission data from the first relay device 30, the MCU 300 of the second relay device 30 obtains measurement data, a sequence number, and a destination address from the received data. And fetch source address and data source address. When receiving the transmission data from the first relay device 30, the MCU 300 of the second relay device 30 transmits an ACK to the first relay device 30 that is the transmission source after the wait time has elapsed (processing T5 in FIG. 1). ).

  Here, the MCU 300 of the first relay device 30 operates the wireless communication unit 302 in the reception state until the first time which is the reception waiting time of the ACK elapses from the time of data transmission, and the first time elapses. All ACKs sent until then are received. Here, the first time is set to a time in which all ACKs can be received when ACKs for the number of relays 30 are continuously transmitted, and is set to, for example, 30 milliseconds in this embodiment. ing. In the example of FIG. 1, since the first relay station 30 receives the ACK to which the final destination information is added from the parent device 20, the parent device 20 is determined as the transmission destination node, and the next time data transmission is performed Send data to 20 by unicast. Further, since the first relay device 30 also receives an ACK from the second relay device 30, the second relay device 30 is stored in the storage unit 301 as a transmission destination candidate node.

  Next, a communication procedure in the case where slave unit 10 transmits measurement data for the second time will be described with reference to FIG. A communication procedure common to the communication procedure described with reference to FIG. 1 will be briefly described.

  The MCU 100 of the slave unit 10 starts from the sleep mode when the next transmission timing comes. The MCU 100 of the slave unit 10 controls the wireless communication unit 102 to transmit transmission data storing the measurement data and the sequence number measured by the measurement unit 108 by broadcast (processing T11 in FIG. 5).

  In the example of FIG. 5, the first to third repeaters 30 receive the data transmitted from the slave 10, and transmit an ACK to the slave 10 of the transmission source (processing T12 of FIG. 5). The MCU 100 of the slave unit 10 operates the wireless communication unit 102 in a reception state after data transmission, and an ACK from the first relay station 30 which has first transmitted an ACK among the first to third relay stations 30. When it receives, it shifts to sleep mode. Here, since the ACK to which the final destination information is added is transmitted from the first relay station 30, the slave unit 10 stores the final address information transmitted from the first relay station 30 in the storage unit 101. . The slave unit 10 determines the first relay station 30 as the transmission destination node, and transmits data in unicast to the first relay station 30 at the next data transmission. Further, in the example of FIG. 5, since the first relay station 30 first transmits an ACK, only the first relay station 30 relays data. Since the second and third relays 30 receive the ACK transmitted from the first relay 30 before transmitting the ACK, they do not perform relay transmission of data but only transmit ACK. When the second and third repeaters 30 receive the data transmitted from the slave 10 and receive an ACK transmitted from the other repeater 30 to the slave 10 for the same data, Neither relay transmission of data nor transmission of ACK to the slave 10 may be performed.

  The MCU 300 of the first relay device 30 takes in the measurement data, the sequence number, the destination address, the transmission source address, and the data source address from the data transmitted from the child device 10 in process T11. Then, the MCU 300 of the first relay device 30 includes the measurement data and the sequence number, and the destination address is the address of the parent device 20, the transmission source address is the own device address, and the data source address of the 11th child device 10 Create send data with address. Then, the MCU 300 of the first relay device 30 controls the wireless communication unit 302 to unicast the transmission data to the master device 20 when the transmission waiting time has elapsed since the data reception (FIG. 5). Processing T13).

  The data transmitted in unicast from the first relay device 30 to the master device 20 is received by the wireless communication unit 202 of the master device 20. When the wireless communication unit 202 of the parent device 20 receives the transmission data from the first relay device 30, the MCU 200 of the parent device 20 does not provide the wait time, and transmits the final destination information to the first relay device 30 which is the transmission source. The added ACK is transmitted (processing T14 in FIG. 5). Thus, the process of transmitting data from the slave unit 10 to the master unit 20 is completed.

  Since the MCU 300 of the first relay device 30 transmits data in unicast, the reception waiting time of ACK is set to a second time shorter than the first time in the case of transmitting data by broadcast. The MCU 300 of the first relay device 30 transmits the wireless communication unit 102 so that the wireless communication unit 102 can receive an ACK during the period from the time when the data is transmitted by unicast until the second time elapses. Control. In the case of transmitting data by unicast, since the transmission destination node is determined, the time until ACK is transmitted is shorter than in the case of transmitting data by broadcast. Therefore, in the present embodiment, the second time is set to a predetermined time (for example, 2 milliseconds) shorter than the first time.

  After the communication path from the handset 10 to the base unit 20 is established as described above, thereafter, the handset 10 → the first relay station 30 → the base unit 20 communication route from the handset 10 to the base unit 20 Data is sent by cast. The communication process in this case will be described according to FIG. A communication procedure common to the communication procedure described with reference to FIGS. 1 and 5 will be briefly described.

  At the next transmission timing, the MCU 100 of the slave 10 starts from the sleep mode, and causes the measuring unit 108 to measure the temperature. The MCU 100 of the slave 10 controls the wireless communication unit 102 to transmit transmission data storing the measurement data and the sequence number measured by the measurement unit 108 to the first relay device 30 by unicast (FIG. 6). Processing T21). The MCU 100 of the slave unit 10 controls the wireless communication unit 102 so that the wireless communication unit 102 can receive an ACK after data transmission.

  When the first relay device 30 receives the data transmitted in unicast from the slave 10, it transmits an ACK to the slave 10 of the transmission source (processing T22 in FIG. 6).

  Further, the first relay device 30 extracts the measurement data, the sequence number, the destination address, the transmission source address, and the data source address from the data received from the slave 10. The first relay station 30, including the measurement data and the sequence number, creates transmission data with the destination address as the address of the parent device 20, the transmission source address as the own device address, and the data source address as the address of the child device 10. Do. Then, when the transmission waiting time has elapsed since the data reception, the first relay device 30 transmits the transmission data to the parent device 20 by unicast (processing T23 in FIG. 6).

  When the master device 20 receives data transmitted by unicast from the first relay device 30, it transmits an ACK to the first relay device 30, which is the transmission source, without providing a wait time (the process of FIG. 6) T24). Thus, the process of transmitting data from the slave unit 10 to the master unit 20 is completed.

  As described above, the relay device 30 according to the present embodiment is the ACK reception waiting time when data is transmitted by broadcast when the second time which is the reception waiting time of ACK when data is transmitted by unicast. It is set to a time shorter than the first time. The relay device 30 changes the reception waiting time of ACK between the time of communication by broadcast and the time of communication by unicast, and this operation will be described based on FIG.

  In FIG. 7, an operation in the case where the fourth relay device 30 which is the lower communication node transmits data to the first relay device 30 which is the upper communication node will be described.

  In the state where the node of the transmission destination is not determined, the fourth relay station 30 transmits data by broadcast, and sets an ACK reception waiting time after data transmission to the first time DT1. When the fourth relay station 30 broadcasts the data D1, the data D1 transmitted from the fourth relay station 30 is received by the first to third relay stations 30. The MCU 300 of the fourth relay device 30 controls the wireless communication unit 302 so that the wireless communication unit 302 can receive an ACK until the first time DT1 elapses from time t1 at which data is transmitted by broadcast. In the example of FIG. 7, the fourth relay station 30 receives an ACK (A11, A21, A31) from the first, second, and third relay stations 30 during the time when the first time DT1 elapses from time t1. Receive As a result, the fourth relay station 30 determines the first relay station 30 that received the first ACK as a transmission destination node, and determines the second and third relay stations 30 as transmission destination candidate nodes. Do. The first relay device 30 transmits the data D11 to the upper node at time t2 when the transmission waiting time has elapsed from the time of receiving the data D1.

  Thereafter, when the fourth relay station 30 receives the data transmitted from the lower node, the relay station 30 transmits the data D2 created based on the received data to the first relay station 30 by unicast. The MCU 300 of the fourth relay device 30 controls the wireless communication unit 302 such that the wireless communication unit 302 can receive an ACK until the second time DT2 elapses from the time of data transmission (time t11). If the MCU 300 of the fourth relay device 30 can receive the ACK (A12) from the first relay device 30 during the time when the second time DT2 elapses from time t11, it determines that the data transmission has succeeded and the data End relay processing of. The first relay device 30 transmits the data D12 to the upper node at time t12 when the transmission waiting time has elapsed from the time of receiving the data D2.

  When the fourth relay station 30 receives the data transmitted from the lower node, the fourth relay station 30 transmits the data D3 created based on the received data to the first relay station 30 by unicast. The MCU 300 of the fourth relay device 30 controls the wireless communication unit 302 such that the wireless communication unit 302 can receive an ACK until the second time DT2 elapses from the time of data transmission (time t13). The MCU 300 of the fourth relay device 30 determines that the data transmission has failed if the wireless communication unit 302 can not receive an ACK during the time from the time t13 to the elapse of the second time DT2. Then, the fourth relay station 30 retransmits the data D3 by unicast to the first relay station 30 when the retransmission waiting time elapses after judging that the data transmission has failed. As described above, in the unicast communication, since the ACK reception waiting time is set to the second time DT2, it is possible to transmit data as compared with the case where the ACK reception waiting time is set to the first time DT1. It reduces the time it takes to resend data if it fails. The fourth relay station 30 relays the first relay station 30 while the second time DT2 elapses from the time (time t14) at which the data D3 is retransmitted in unicast to the first relay station 30. If ACK (A13) can be received from S30, the data retransmission process is ended.

  In the wireless communication system of the present embodiment, when a sensor for measuring a physical quantity to be measured (temperature, humidity, illuminance, etc.) is connected to the relay unit 30, the master unit 20 is a sensor for the relay unit 30. There are also cases where request data that requests measurement data is transmitted. Further, there are also cases where the master unit 20 transmits request data for requesting measurement data of the sensor to the slave unit 10. In this case, the master unit 20 becomes a transmission source node, and the relay unit 30 or slave unit 10 for which measurement data is requested becomes a final destination node.

  Moreover, in the present embodiment, if the handset 10 can receive an ACK after data transmission, it shifts to the sleep mode, but as in the case of the relay unit 30, radio is performed from the time of data transmission until the reception waiting time elapses. The communication unit 102 may be able to receive an ACK. The slave unit 10 transmits the data in the second time DT2 in which the wireless communication unit 102 can receive the ACK when transmitting data by unicast, and the wireless communication unit 102 can receive the ACK when transmitting data by broadcast. It may be set to a time shorter than the first time when it is in the normal state.

  As described above, the control unit (MCU 100, 200, 300) of the communication node (the slave unit 10, the master unit 20, the relay unit 30) wirelessly transmits data by broadcast in the state where the communication path is not established. The communication unit (wireless communication units 102, 202, 302) is controlled. Then, when the transmission destination node is determined by establishing at least a part of the communication path to the final destination node, the control unit transmits the data to the transmission destination node in unicast so as to transmit the data to the transmission destination node. Control. Since the communication node determined by the transmission destination node transmits data in unicast to the transmission destination node, the number of ACKs to be transmitted is reduced as compared with the case of transmitting data by broadcast. Therefore, the amount of communication is reduced, and the possibility of collision of transmission data is reduced. Furthermore, the control unit of the communication node is a reception waiting time when data is transmitted by broadcast, the reception waiting time when the wireless communication unit can receive an ACK when the data is transmitted by unicast. The second time DT2, which is shorter than the time DT1, is set. As a result, when the communication node fails to transmit data in unicast, the time to retransmit the data becomes shorter than that in data transmission by broadcast, and the arrival time required for the data to reach the final destination node It can be shortened. In particular, when the number of relay hops to the final destination node is large, the time until data is resent at each relay node becomes short, so the effect of shortening the arrival time taken for data to reach the final destination node Becomes larger.

  Further, in the present embodiment, the control unit of each communication node stores, in the storage unit as candidate nodes, all nodes that have transmitted ACK when the wireless communication unit transmits data by broadcast. When data transmission from the wireless communication unit to the transmission destination node fails, the control unit of each communication node transmits data in unicast to candidate nodes other than the transmission destination node among the candidate nodes stored in the storage unit. The wireless communication unit may be controlled to do so.

  Here, the first to fourth relay devices 30 are provided, and the fourth relay device 30 determines the first relay device 30 as a transmission destination node, and the second and third relay devices 30 are candidate nodes. The operation in the case of the above will be described based on FIG.

  When the fourth relay station 30 transmits the data D4 received from the lower node to the first relay station 30 at time t15, if the first relay station 30 fails to receive the data D4 due to a communication error, The ACK is not transmitted from the first relay station 30 to the fourth relay station 30. Therefore, the wireless communication unit 302 of the fourth relay device 30 can not receive an ACK from the first relay device 30 until the second time DT2 elapses from the transmission time point of the data D4. Since the MCU 300 of the fourth relay device 30 can not receive the ACK from the first relay device 30, it determines that communication with the first relay device 30 has failed, and the candidate node (stored in the storage unit 301 ( One of the second and third repeaters 30) is determined as the transmission destination node. Here, measured values of received signal strength are stored in the storage unit 301 of the fourth repeater 30 for each of the second and third repeaters 30 that are candidate nodes. The MCU 300 of the fourth repeater 30 is a node having a higher received signal strength among the second and third repeaters 30 based on the reception signal strength stored in the storage unit 301, for example, the second repeater Determine 30 as the destination node. Then, at time t16, the MCU 300 of the lower level relay device 30 controls the wireless communication unit 302 to unicast the data D4 for which transmission has failed to the second number relay device 30. When the wireless communication unit 302 receives an ACK (A22) from the second relay device 30 after transmitting the data D4 in unicast, the MCU 300 of the fourth relay device 30 determines that the data D4 has been successfully transmitted. Communication processing is terminated.

  Thereafter, when the MCU 300 of the fourth repeater 30 receives the data D5 from the lower node, the MCU 300 controls the wireless communication unit 302 to unicast the received data D5 to the second repeater 30 (time t17). ). The MCU 300 of the fourth relay device 30 controls the wireless communication unit 302 in a state in which the wireless communication unit 302 can receive an ACK from the time when the data D5 is transmitted by unicast until the second time DT2 elapses. .

  When the second relay station 30 fails to receive the data D5 due to a communication error or the like, the wireless communication unit 302 of the fourth relay station 30 takes a period of time from the transmission of the data D4 to the elapse of the second time DT2. The ACK from the second relay station 30 can not be received. Since the MCU 300 of the fourth relay device 30 can not receive the ACK from the second relay device 30, it determines that communication with the second relay device 30 has failed, and the candidate node stored in the storage unit 301 The third relay station 30 is determined as the transmission destination node. Then, at time t18, the MCU 300 of the fourth relay device 30 controls the wireless communication unit 302 to unicast the data D5 for which transmission has failed to the third relay device 30. If the wireless communication unit 302 of the fourth relay device 30 receives an ACK (A32) from the third relay device 30 while the second time DT2 elapses from the time of transmission of the data D5 (time t18), 4 The MCU 300 of the relay device 30 determines that the transmission of the data D5 is successful. When the transmission of the data D5 is successful, the MCU 300 of the fourth relay device 30 ends the communication processing.

  As described above, when each communication node (the slave unit 10, the master unit 20, or the relay unit 30) fails to transmit data to the destination node, it transmits the data to the candidate node by unicast, The time required to reconstruct the communication path to the final destination node can be shortened. Moreover, since the control unit of the communication node shortens the ACK reception waiting period to the second time T2 also when retransmitting data to the candidate node, it is possible to transmit data as compared to retransmitting data by broadcast. The time to retransmit the data in case of failure is shortened. Therefore, it is possible to shorten the arrival time required for data to reach from the source node to the final destination node.

  By the way, the second time DT2 is set to the maximum time taken for the wireless communication unit (wireless communication units 102, 202, 302) to transmit data to the transmission destination node in unicast and to receive an ACK. Is preferred. The control unit of each communication node stores, for example, the time taken for the wireless communication unit to transmit data to the transmission destination node in unicast after receiving data in a data collection period of about several hours. It records in the part 101, 201, 301). Then, the control unit of each communication node may set the maximum time of the times stored in the storage unit to the second time DT2. As a result, when data transmission in unicast from each communication node to the destination node is normally performed, the ACK transmitted from the destination node can be reliably received. The second time DT2 may be set for each node of the transmission destination because the time from the transmission of data to the reception of the ACK may differ depending on the transmission destination node.

  Further, in the wireless communication system according to the present embodiment, the control unit of each communication node performs wireless communication so as to retransmit data to the transmission destination node when the wireless communication unit fails to transmit data to the transmission destination node. You may control the department. Then, when the number of retransmissions for retransmitting data to the transmission destination node becomes equal to or greater than the specified number, the control unit of each communication node sets the reception waiting time in the case of transmitting data by unicast to the third time. Good. Here, the third time may be longer than the second time DT2 and shorter than the first time DT1.

  For example, communication processing in a case where the fourth relay station 30 sets the first relay station 30 as a transmission destination node will be described based on FIG.

  The MCU 300 of the fourth repeater 30 receives the data from the lower node, transmits the transmission data D6 created based on the received data to the first repeater 30 by unicast, and transmits the transmission data D6 to the first repeater 30. It controls (time t21). The MCU 300 of the fourth relay device 30 controls the wireless communication unit 302 in a state in which the wireless communication unit 302 can receive an ACK until the second time DT2 elapses from the time of transmitting the data D6 by unicast. .

  Here, when the first relay device 30 fails to receive the data D6 due to a communication error or the like, the wireless communication unit 302 of the fourth relay device 30 continues until the second time DT2 elapses from the transmission time point of the data D6. Can not receive an ACK from the first relay station 30 during the period. Since the MCU 300 of the fourth repeater 30 can not receive the ACK from the first repeater 30, it determines that communication with the first repeater 30 has failed, and the data D6 is sent to the first repeater 30. The wireless communication unit 302 is controlled to retransmit by unicast (time t22). The MCU 300 of the fourth relay device 30 keeps the wireless communication unit 302 in a state in which the wireless communication unit 302 can receive an ACK until the second time DT2 elapses from the time (time t22) at which the data D6 is transmitted by unicast. Control 302;

  When the first relay station 30 fails to receive the data D6 again due to a communication error or the like, the wireless communication unit 302 of the fourth relay station 30 waits until the second time DT2 elapses from the transmission time point of the data D6. Can not receive an ACK from the first relay station 30. Since the MCU 300 of the fourth repeater 30 can not receive the ACK from the first repeater 30, it determines that communication with the first repeater 30 has failed, and the data D6 is sent to the first repeater 30. The wireless communication unit 302 is controlled to retransmit by unicast (time t23). The MCU 300 of the fourth relay station 30 counts the number of retransmissions for retransmitting data to the destination node, and when the number of retransmissions is equal to or greater than a prescribed number (for example, two), the reception waiting time is set to the second time DT2 A third time DT31 is set which is longer than the first time DT1 and shorter than the first time DT1. Since the reception waiting time is extended to the third time DT31, the radio wave repeatedly strikes the obstacle on the communication path between the fourth relay station 30 and the first relay station 30, and the ACK is the fourth relay station. Even if it takes a long time to reach the aircraft 30, it becomes easy to receive an ACK.

  Also, when the number of retransmissions for retransmitting data to the transmission destination node becomes equal to or greater than the specified number, the control unit of each communication node receives the reception waiting time when data is transmitted by unicast as the number of retransmissions increases. 3 hours may be extended gradually.

  In the example of FIG. 9, the MCU 300 of the fourth relay device 30 sets the ACK reception waiting time to the third time DT31 when the number of retransmissions of the data D6 becomes two (prescribed number of times). Then, when the number of retransmissions of the data D6 reaches three, the MCU 300 of the fourth relay device 30 sets the ACK reception waiting time to the third time DT32 (DT31 <DT32 <DT1). As described above, when the number of times of data retransmission is equal to or more than the specified number, the MCU 300 of the fourth relay device 30 gradually increases the ACK reception waiting time. Therefore, an electric wave repeatedly strikes an obstacle or the like on the communication path between the fourth repeater 30 and the first repeater 30 and the time for the ACK to reach the fourth repeater 30 becomes longer. In this case, it is easy to receive an ACK.

  In addition, when the number of retransmissions for retransmitting data to the destination node becomes equal to or greater than a prescribed number, the control unit of each communication node is in a state where the wireless communication unit can receive an ACK when data is transmitted by unicast. The reception waiting time may be set to the same time as the first time DT1.

  As described above, when the number of times of data retransmission is equal to or more than the specified number, the MCU 300 of the relay device 30 waits for an ACK, and the same time as the first time DT1 which is an ACK reception wait time for transmitting data by broadcast. I have to. As a result, radio waves are hit on an obstacle or the like on the communication path between the two repeaters 30 and the reflection is repeated, so that the ACK is received even when the time until the ACK reaches the sender repeater 30 becomes long. It becomes easy to do. Note that setting the reception waiting time to the same time as the first time DT1 is not limited to making the time identical to the first time, but there may be a slight time difference due to a manufacturing error or the like.

  Further, in the wireless communication system according to the present embodiment, the control unit of each communication node performs wireless communication so as to retransmit data to the transmission destination node when the wireless communication unit fails to transmit data to the transmission destination node. You may control the department. Then, the control unit of each communication node may control the wireless communication unit to transmit data by broadcast when the number of retransmissions for retransmitting data to the destination node reaches the maximum number of retransmissions.

  For example, communication processing in the case where the fourth relay device 30 sets the first relay device 30 as a transmission destination node will be described based on FIG.

  The MCU 300 of the fourth repeater 30 receives the data from the lower node, transmits the transmission data D7 created based on the received data to the first repeater 30 by unicast, and transmits the transmission data D7 to the first repeater 30. It controls (time t31). The MCU 300 of the fourth relay device 30 controls the wireless communication unit 302 in a state in which the wireless communication unit 302 can receive an ACK from the time when the data D7 is transmitted by unicast until the second time DT2 elapses. .

  Here, when the first relay device 30 fails to receive the data D7 due to a communication error or the like, the wireless communication unit 302 of the fourth relay device 30 continues until the second time DT2 elapses from the transmission time point of the data D7. Can not receive an ACK from the first relay station 30 during the period. Since the MCU 300 of the fourth repeater 30 can not receive the ACK from the first repeater 30, it determines that communication with the first repeater 30 has failed, and the data D7 is sent to the first repeater 30. The wireless communication unit 302 is controlled to retransmit by unicast (time t32). The MCU 300 of the fourth relay device 30 controls the wireless communication unit 302 in a state in which the wireless communication unit 302 can receive an ACK from the time when the data D7 is transmitted by unicast until the second time DT2 elapses. .

  When the first relay station 30 fails to receive the data D7 again due to a communication error or the like, the wireless communication unit 302 of the fourth relay station 30 waits until the second time DT2 elapses from the transmission time point of the data D7. Can not receive an ACK from the first relay station 30. Since the MCU 300 of the fourth repeater 30 can not receive the ACK from the first repeater 30, it determines that communication with the first repeater 30 has failed, and the data D7 is sent to the first repeater 30. The wireless communication unit 302 is controlled to retransmit by unicast (time t33).

  Here, the MCU 300 of the fourth relay station 30 counts the number of retransmissions for retransmitting data to the destination node, and when the number of retransmissions reaches the maximum number of retransmissions (for example, four), it broadcasts the data D7. The radio communication unit 302 is controlled to transmit the time t35 (time t35). In the example of FIG. 10, when handset 10 retransmits data at time t35, the number of retransmissions reaches the maximum number of retransmissions, so that MCU 300 of relay station 30 No. 4 transmits data D 7 by broadcast. The wireless communication unit 302 is controlled. The MCU 300 of the fourth repeater 30 transmits the data from the wireless communication unit 302 so that the wireless communication unit 302 can receive an ACK during the period from when the data is transmitted by broadcast until the first time DT1 elapses. Control.

  As described above, when the number of retransmissions for retransmitting data reaches the maximum number of retransmissions, the control unit of each communication node controls the wireless communication unit to transmit data by broadcast, so that any data communication node Is more likely to be received. Therefore, the probability of data reaching the final destination node is high, and data can be more reliably reached from the source node to the final destination node.

  In the example of FIG. 10, when the number of retransmissions reaches the maximum number of retransmissions, the control unit of each communication node controls the wireless communication unit to transmit data by broadcast, but the number of retransmissions is the maximum number of retransmissions. When reached, the control unit of each communication node may end the data retransmission process.

  If the number of retransmissions reaches the maximum number of retransmissions, it is expected that communication errors are likely to occur due to deterioration of the radio wave environment or malfunction of the destination node, etc. It is possible to avoid the case where the retransmission of is repeated again.

  In addition, when the control unit of each communication node controls the wireless communication unit to end the data retransmission process because the number of retransmissions reaches the maximum number of retransmissions, the control unit of the communication node transmits new data at the next transmission. The wireless communication unit may be controlled.

  For example, as shown in FIG. 10, when the number of retransmissions of data reaches the maximum number of transmissions, the M300 of the fourth relay device 30 controls the wireless communication unit 302 to transmit data D7 by broadcast. Then, the MCU 300 of the fourth relay device 30 causes the wireless communication unit 302 to be able to receive an ACK from the wireless communication unit 302 until the first time DT1 elapses from the time when the data D7 is transmitted by broadcast. Control 302; The MCU 300 of the fourth relay device 30 ends the transmission process of the data D7 when the first time DT1 elapses from the time of transmitting the data D7 by broadcasting. Then, when the MCU 300 of the fourth repeater 30 receives new data D8 from the lower communication node, the MCU 300 unicasts this data D8 to the first repeater 30, which is the transmission destination node at the previous transmission time. The wireless communication unit 302 is controlled so as to (step t36).

  As described above, the control unit of each communication node controls the wireless communication unit to end the data retransmission process when the number of data retransmissions reaches the maximum number of retransmissions, but the data retransmission process is completed. In this case, the wireless communication unit may be controlled to transmit new data at the next transmission. Thus, the control unit of each communication node can resume the process of transmitting data to the destination node.

  Further, in the wireless communication system of the present embodiment, the transmission source node and the relay node transmit data by broadcast in a state where a communication path for transmitting data from the transmission source node to the final destination node has not been established. Among the transmission source node and the relay node, a node whose transmission destination is determined by establishment of at least a part of the communication path transmits data by unicast. Then, the transmission source node and the relay node are capable of receiving an ACK upon receiving data by unicast, and are capable of receiving an ACK upon transmitting data by broadcast. Set the second time shorter than the time. In the present embodiment, when data is transmitted from the slave 10 to the master 20, the slave 10 is a transmission source node, the master 20 is a final destination node, and the relay 30 is a relay node. When data is transmitted from the master unit 20 to the slave unit 10, the master unit 20 is a transmission source node, the slave unit 10 is a final destination node, and the relay unit 30 is a relay node.

  As described above, when the transmission destination node is determined, the data is transmitted by unicast to the transmission destination node, so the number of ACKs to be transmitted is reduced compared to the case of transmitting the data by broadcast. Therefore, the amount of communication is reduced, and the possibility of collision of transmission data is reduced. Furthermore, when the data is transmitted by unicast, the reception waiting time in which the wireless communication unit can receive the ACK is shorter than the first time DT1, which is the reception waiting time when the data is transmitted by broadcasting. It is set to time DT2. As a result, when data transmission in unicast fails, the time to retransmit the data becomes shorter compared to data transmission in broadcast, and the arrival time required for the data to reach the final destination node can be shortened. In particular, when the number of relay hops to the final destination node is large, the time until data is resent at each relay node becomes short, so the effect of shortening the arrival time taken for data to reach the final destination node Becomes larger. The wireless communication system of the present embodiment can appropriately adopt the functions of the respective communication nodes described in the above embodiments.

  The communication method of the present embodiment is a communication method adopted by the above-described wireless communication system, and includes the following steps 1 to 3. Step 1 is a step of causing the wireless communication unit (the wireless communication units 102, 202, 302) to transmit data by broadcast in a state where the communication path to the final destination node is not established. Step 2 is a step of causing the wireless communication unit to transmit data in unicast to the destination node when the destination node is determined by establishing at least a part of the communication path to the final destination node. In step 3, the wireless communication unit becomes ready to receive an ACK when data is sent by broadcast when the wireless communication unit is ready to receive an ACK when transmitting data by unicast. It is a step which sets to the 2nd time shorter than the 1st time.

  By adopting such a communication method, it is possible to shorten the arrival time required for data to reach the final destination node. In addition, the communication method of this embodiment can employ | adopt suitably the various communication methods demonstrated by said embodiment.

10 handsets (communication node, source node)
20 parent machine (communication node, final destination node)
30 Repeater (communication node, relay node)
100, 200, 300 MCU (control unit)
101, 201, 301 storage unit 102, 202, 302 wireless communication unit DT1 first time DT2 second time DT31, DT32 third time

Claims (10)

A wireless communication unit for performing wireless communication and a control unit ;
The control unit
If the communication path from the own node to the final destination node has not been established , send data to other nodes by broadcast.
In a state in which a communication route from the own node to the final destination node is the destination node has been established it is determined to transmit the data in unicast to the destination node,
A communication node that controls the wireless communication unit to receive an ACK from the other node or the determined destination node ,
The data includes a first measurement data and a second measurement data measured after a prescribed time has elapsed since the first measurement data was measured,
The control unit
An ACK including information indicating that a communication path from the own node to the final destination node has been established based on the final destination information from any of the nodes that have received the first measurement data transmitted by broadcast. Determining the destination node by transmitting the first measurement data in a broadcast and receiving the first measurement data in a lapse of a first time,
When transmitting the second measurement data next time, the second measurement data is transmitted by unicast to the transmission destination node,
The node can not receive the ACK from the node of the transmission destination after the second measurement data is transmitted by unicast and until the second time shorter than the first time elapses, the node of the transmission destination can not be received Controlling the wireless communication unit to retransmit the second measurement data if the transmission of the second measurement data to the storage device fails.
Communication node. The storage unit is further provided,
Wherein the control unit, the wireless communication unit is stored in the storage unit every node having transmitted the ACK when transmitting the first measurement data broadcast as a candidate node,
Wherein, the radio if the communication unit fails to send the second measurement data to the destination node, the other than the node of the destination of the candidate nodes stored in the storage unit The communication node according to claim 1, wherein the wireless communication unit is controlled to transmit the second measurement data in unicast to a candidate node. The control unit is a maximum time taken from reception of the ACK by the wireless communication unit after transmitting the second measurement data in unicast to the transmission destination node in a prescribed data collection period. communication node according to claim 1 or 2, characterized in that it is configured to set as the second hour. Prior Symbol controller, when the number of the second measurement data has been retransmitted in unicast to the destination node is equal to or more than a specified number of times, longer than the second time, and, from the first hour The communication node according to any one of claims 1 to 3, wherein the new second time is set to a short third time. Prior Symbol controller, configuration when the number of re-transmitting the second measurement data in unicast to the destination node is equal to or more than a specified number of times, the second time to change to the first hour The communication node according to any one of claims 1 to 3, characterized in that: Prior Symbol controller, the number of retransmissions of re-transmitting the second measurement data to the destination node by unicast reaches the maximum number of retransmissions, the wireless to transmit the second measurement data broadcast The communication node according to any one of claims 1 to 5, which controls the communication unit. Prior Symbol controller, when the number of times of re-transmitting the second measurement data to the destination node by unicast reaches the maximum number of retransmissions, the wireless to end the retransmission process of the second measurement data The communication node according to any one of claims 1 to 5, which controls the communication unit. Wherein, when controlling the radio communication unit to terminate the retransmission process of the second measurement data, the controller controls the wireless communication unit to transmit the new the data at the next transmission The communication node according to claim 7, characterized in that: Causing the wireless communication unit to transmit data by broadcast in a state where a communication path from the own node to the final destination node has not been established;
In a state in which the final destination node until the communication route is the destination has been established node from the own node is determined, the step of transmitting the data in unicast to the destination node to the radio communication unit ,
The data is broadcasted by an ACK indicating that a communication path from the own node to the final destination node has been established based on the final destination information from any of the nodes that have received the data transmitted by broadcast. The node of the transmission destination is determined by receiving during the time when the first time elapses, and the data is unicasted to the node of the transmission destination determined when transmitting the data next time. Sending it,
In the case where transmission of the data to the transmission destination node fails because the ACK can not be received before the second time shorter than the first time elapses after the data is transmitted by unicast. Controlling the wireless communication unit to retransmit the data;
A communication method comprising: A source node having a wireless communication function;
A final destination node having a wireless communication function;
A plurality of relay nodes having a function of relaying wireless communication between the source node and the final destination node;
The source node and the relay node
When the communication path of data from the own node to the final destination node is not established, the data is transmitted to the other node by broadcast.
To the node which decided destination by pre Symbol communication route is established, and transmits the data in unicast,
A wireless communication system configured to receive an ACK from the other node or the determined destination node ,
The data includes a first measurement data and a second measurement data measured after a prescribed time has elapsed since the first measurement data was measured,
The source node and the relay node
From any of the nodes that have received the first measurement data transmitted by broadcast, broadcasts an ACK indicating that the communication path from the own node to the final destination node has been established based on final destination information, A destination node is determined by transmitting the first measurement data and receiving the first measurement data after the lapse of a first time,
Transmitting the second measurement data in unicast to the destination node when transmitting a next second measurement data,
It is not possible to receive the ACK after the second measurement data is transmitted by unicast and before the second time shorter than the first time elapses, the second to the destination node can not be received. Retransmitting the second measurement data if transmission of the measurement data fails;
A wireless communication system characterized in that.

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