JP6658828B1 - Wireless communication device, wireless communication program, and wireless communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare for an isolated node to transmit data without requiring a burden on the network such as providing a control packet for the isolated node and a transmission time. A wireless communication device according to the present invention is a wireless communication device in which an isolated node transmits a data signal, and the wireless receiving device and all communications that can be received by the wireless receiving device including those other than addressed to the own node. It is characterized by comprising network management means for intercepting a signal and wireless transmission means for transmitting a data signal addressed to a parent node, which is determined based on information included in the received communication signal. [Selection diagram] Fig. 1

Description

  The present invention relates to a wireless communication device, a wireless communication program, and a wireless communication method, and can be applied to, for example, a wireless communication device mounted on a node configuring a multi-hop wireless communication system.

  In a multi-hop wireless communication system, for example, when a node moves or a surrounding environment fluctuates, the wireless communication quality between nodes is affected, and the wireless communication quality between nodes changes every moment. .

  Therefore, even in the case of a node that was connectable in the past, communication may not be performed, and as a result, there is a possibility that a node having zero adjacent nodes (hereinafter, also referred to as an “isolated node”) may occur. is there.

  In a general multi-hop wireless communication system, a parent node that is a destination of data of the own node is determined by exchanging control packets. However, an isolated node cannot determine its parent node and cannot transmit data. Therefore, a mechanism for transmitting data even when the node becomes an isolated node has been researched and developed.

Patent Document 1, a method of isolation node transmits a packet to inform the neighboring nodes that isolated, detects the isolated node by being detected by the interference to other packet other nodes due to the packet Also, a method has been proposed in which a node receiving the packet itself transmits a control packet to an isolated node.

  According to Non-Patent Document 1, in a superframe, a packet for requesting data retransmission is transmitted to a node from which a base station cannot receive data, and the node receiving the packet transmits a control packet. There has been proposed a method of increasing the chance that an isolated node can receive a control packet.

  Here, the superframe indicates a time width divided at regular intervals, and in the superframe, the construction of a network path and the transmission of data are performed. Periodic data collection becomes possible by repeating the superframe.

JP 2010-505345 A

2013 IEEE 77th Vehicular Technology Conference, paper "Low-Power, End-to-End Reliable Collection using Glossy for Wireless Sensor".

  However, both Patent Literature 1 and Non-Patent Literature 1 require a mechanism in which all nodes participating in a network including a base station detect an isolated node, and in order to detect, each node transmits a control packet. In need.

  The transmission of control packets increases the load on the network, and in a network accommodating a large number of nodes and transmitting and receiving packets at a high frequency, the load cannot be ignored.

  In addition, Non-Patent Literature 1 provides a retransmission time for an isolated node, which causes deterioration in the time efficiency of the network.

  Further, both Patent Literature 1 and Non-Patent Literature 2 make use of the characteristic of wireless communication that the communication quality changes with the passage of time even if it is an isolated node, and re-communication becomes possible.

  In view of the above-described problems, a wireless communication device, a wireless communication program, and a wireless communication apparatus capable of transmitting data without requiring a load on the network such as providing a control packet and a transmission time for the isolated node are required. A wireless communication method is desired.

In order to solve such a problem, a wireless communication apparatus according to a first aspect of the present invention transmits a communication signal in which application layer information is encrypted, and layer information below a network layer is not encrypted to a base station. In a wireless communication device of each node of a multi-hop wireless communication system performing wireless communication by multi-hop , (1) wireless receiving means, and (2) information included in a path control signal received within a predetermined path construction period Network management means for creating a routing table based on the above, determining a parent node and performing wireless communication processing ; (3) wireless transmission means for transmitting a communication signal addressed to the parent node determined by the network management means ; 4) in accordance with the presence or absence of the reception of the route control signal in the path construction period, the own node is a isolation determination means that determines whether an isolated node, network When the isolation determining unit determines that the own node is an isolated node, the work management unit sets a timer until the start of the transmission period of the own node in a predetermined interception period, and sets the timer to the wireless reception unit. An interception command unit that issues a command to intercept all receivable communication signals including those not addressed to the node, and a parent node that determines a parent node based on source information of the communication signal received by the wireless reception unit during the interception period And a determining unit .

According to a second aspect of the present invention, there is provided a wireless communication program for performing multi-hop wireless communication of a communication signal to a base station, wherein information of an application layer is encrypted, and layer information below a network layer is not encrypted. In a wireless communication program of each node of the hop wireless communication system , a computer is configured to execute a routing table based on (1) wireless receiving means and (2) information included in a route control signal received within a predetermined route construction period. create and network management means for performing radio communication processing to determine the parent node, and a wireless transmitting means for transmitting a communication signal addressed to the parent node determined by (3) a network management unit, (4) route construction period depending on the presence or absence of the reception of the route control signal at an internal, to function in an isolated judging means for judging the own node is whether isolated node When the isolation determining means determines that the own node is an isolated node, the network management means sets a timer until the start of the transmission period of the own node in a predetermined interception period, An interception command unit that issues a command to intercept all of the receivable communication signals including those not addressed to the node, and a parent that determines a parent node based on transmission source information of the communication signal received by the wireless reception unit during the interception period. It is characterized by functioning as a node determination unit .

In the wireless communication method according to the third aspect of the present invention, the information of the application layer is encrypted, and the layer information below the network layer is not encrypted. In the wireless communication method of each node of the hop wireless communication system , (1) a network management unit creates a routing table based on information included in a routing control signal received within a predetermined routing period, and a parent node. And (2) wireless transmission means transmits a communication signal addressed to the parent node determined by the network management means , and (3) isolation control means performs route control within the route construction period. It is determined whether or not the own node is an isolated node according to whether or not the signal has been received. If it is determined that the node is in the communication mode, a timer is set until the start of the transmission period of the own node in a predetermined interception period, and all the above-mentioned communication that can be received by the wireless receiving means including those not addressed to the own node is set. A command is issued to intercept the signal, and the parent node is determined based on the transmission source information of the communication signal received by the wireless reception unit during the interception period .

  ADVANTAGE OF THE INVENTION According to this invention, an isolated node can transmit data, without requiring load on a network, such as providing a control packet and transmission time for an isolated node.

FIG. 2 is an internal configuration diagram illustrating an example of an internal configuration of a wireless communication device of the node according to the embodiment. FIG. 1 is an overall configuration diagram illustrating an example of an overall configuration of a wireless communication system according to an embodiment. FIG. 2 is a diagram illustrating a node arrangement in the wireless communication system according to the embodiment. 6 is a flowchart illustrating a wireless communication process in the mobile station according to the embodiment.

(A) Main Embodiment Hereinafter, embodiments of a wireless communication device, a wireless communication program, and a wireless communication method according to the present invention will be described in detail with reference to the drawings.

(A-1) Configuration of Embodiment [Overall Configuration of System]
FIG. 2 is an overall configuration diagram showing an example of the overall configuration of the wireless communication system (wireless communication network) according to this embodiment.

  2, a wireless communication system 1 according to this embodiment includes a base station 10 and a plurality (five in FIG. 2) of mobile stations 20 (20-1 to 20-5).

  In addition, the numbers of the base stations 10 and the mobile stations 20 are not limited. Hereinafter, the base station 10 and each mobile station 20 may be collectively referred to as a “station” or a “node”.

  In this embodiment, each mobile station 20 is equipped with one or more sensors, acquires sensor data sensed by each sensor, and transmits each mobile station 20 to the base station 10 as necessary. Assume the system. That is, the case where each mobile station 20 transmits sensing data to the base station 10 and the base station 10 collects sensing data from each mobile station 20 is exemplified.

  For example, when a specific low-power radio is used in a sensor network system, a sufficient communication distance may not be ensured due to the characteristics of a frequency band to be used and restrictions on transmission output. Therefore, not all nodes within the area (radio wave reach range) managed by one base station cannot always directly communicate with the base station 10.

  Therefore, in such a wireless communication system 1, a node transmits data to a node existing in an area where the node can directly communicate (hereinafter, also referred to as an “adjacent node”), and further, the node that has received the data transmits the data. Data transmission is performed by multi-hop communication in which data is transmitted to an adjacent node. This wireless communication system is hereinafter referred to as a multi-hop wireless communication system.

  The wireless communication system 1 constitutes a tree-structured multi-hop wireless communication system in which the base station 10 is a “root”, and each mobile station 20 is a “node” and a “leaf”.

  Each station (each node) configuring the multi-hop wireless communication system can be, for example, one that can support the wireless communication method of IEEE 802.15.4. The wireless communication system is not limited to IEEE 802.15.4 as long as multi-hop wireless communication is possible between the stations.

  The mobile body fixing each mobile station 20 is not particularly limited, and may be, for example, a human, a car, a bicycle, a movable robot, an unmanned aerial vehicle, and the like. Further, the type of sensor mounted on each mobile station 20 is not particularly limited, and may be, for example, a temperature / humidity sensor or an acceleration sensor. For example, when the mobile object that fixes the mobile station 20 is a human, a sensor that senses pulse data, heart rate data, and the like of the human body may be used.

  A unique address (for example, a MAC address, a short address, an IP address, etc.) on the network is assigned to the base station 10 and each mobile station 20. Communication is performed between the base station 10 and each mobile station 20, but no communication is performed between the mobile stations 20. That is, each mobile station 20 transmits a unicast data packet destined for the base station 10 as a final destination, but transmits a unicast data packet destined for another mobile station 20 as a final destination. No transmission is performed. If communication between the mobile stations 20 is required, the communication may be performed by relaying the base station 10.

  For example, when the base station 10 and each mobile station 20 perform wireless communication, communication quality may be affected if an obstacle exists between the stations. For example, when a human body exists between the stations, the human body may become an obstacle, and the communication quality may deteriorate. Further, for example, when a mobile object fixing the mobile station 20 is a human, the person's body fixing the mobile station 20 may become an obstacle. As a result, the number of adjacent nodes may become “0” and the own node may be isolated from the network, even though a certain mobile station 20 exists within a connectable range with another node. The reason why an isolated node occurs is not limited to the above example.

[Base station 10 and each mobile station 20]
The base station 10 is a fixedly arranged wireless communication device (wireless device), and manages the entire wireless communication system 1. The base station 10 is also called a fixed station. The base station 10 collects data by receiving information (packets) including data from each mobile station 20 by multi-hop wireless communication. The data collected by the base station 10 may be stored in the base station 10, or may be provided to an information processing device that is connected to the base station 10 wirelessly or by wire. This embodiment does not particularly limit the use of the collected data.

  Each mobile station 20 (20-1 to 20-5) is a wireless communication device (wireless device) attached to a mobile object. Each mobile station 20 is also called a radio station. Each mobile station 20 has a sensor. The sensor measures the measurement target constantly or intermittently (meaning includes periodic and periodic), and each mobile station 20 transmits a packet including data measured by the sensor of its own node to the base station 10. As a final destination by multi-hop radio transmission.

  Each mobile station 20 has a sensor, whereas the base station 10 does not have a sensor. The functions of the mobile station 20 and the base station 10 are different from each other. Good. Hereinafter, the internal configuration of the wireless communication device of each node (each mobile station 20 or base station 10) will be described with reference to FIG.

  FIG. 1 is an internal configuration diagram illustrating an example of an internal configuration of a wireless communication device of a node according to this embodiment.

  In FIG. 1, the node (the mobile station 20 or the base station 10) of this embodiment has a wireless communication device 100 and an external system 111.

  The wireless communication device 100 includes an antenna unit 101, a wireless signal receiving unit 102, a data processing unit 103, a network management unit 104, a storage unit 105, an isolation determining unit 106, a timer unit 107, a packet generating unit 108, a wireless signal transmitting unit 109, and an antenna unit 110.

  Here, the hardware of the wireless communication device 100 includes, for example, a CPU, a ROM, a RAM, an EEPROM, an input / output interface, a communication device, and the like. ). The wireless communication program may be installed to establish wireless communication. Even in such a case, each function of the wireless communication program may be represented as each processing unit of the wireless communication device 100 in FIG. Can be.

  The external system 111 performs functions other than the wireless communication processing. For example, when the node in FIG. 1 is the mobile station 20, the external system 111 may be a sensor or the like. When the node in FIG. 1 is the base station 10, the external system 111 may be a functional unit (application) that performs processing using sensor data collected from each mobile station 20.

  The antenna unit 101 captures an incoming radio wave, converts a radio wave into an electric signal, and supplies the electric signal to the radio signal receiving unit 102. The antenna unit 110 transmits a transmission signal from the radio signal transmission unit 109 on a radio wave. Here, the case where the receiving antenna unit 101 and the transmitting antenna unit 110 are physically different is illustrated, but a shared antenna unit for transmitting and receiving may be used.

  Radio signal receiving section 102 performs demodulation processing and the like of the signal from antenna section 101, and supplies the received packet data to data processing section 103.

  The data processing unit 103 processes the packet data obtained by the wireless signal receiving unit 102. The data processing unit 103 determines the type of the packet, and if the received packet is a control packet, gives the control packet to the network management unit 104. When the received packet is a data packet and is to be transmitted to the base station 10, the data processing unit 103 transmits the data packet to the network management unit 1 to transfer the data packet to another node by multi-hop. -4. Further, when the node is the base station 10 and the received packet is a data packet, the data processing unit 103 gives the data packet to the external system 111.

  The network management unit 104 manages the wireless communication processing of the own node based on information included in the packet acquired from the data processing unit 103. The network management unit 104 includes a route construction unit 104a, an intercept command unit 104b, and a parent node determination unit 104c.

  The route construction unit 104a creates a route table from the data processing unit 103 to a parent node based on information included in a control packet (hereinafter, also referred to as a “route control packet”) related to route construction. This embodiment exemplifies a case in which a proactive routing protocol is applied. Various protocols can be applied as long as the protocol is a proactive type routing protocol. For example, OLSR (Optimized Link State Routing), TBRPF (Topology Broadcast Based on-Reverse-Path Forwarding), LAN MAR, FSR, etc. are widely applied. it can. Periodically, routing packets are flooded to all nodes. The route construction unit 104a of each node recognizes another node (adjacent node) adjacent to the own node based on information included in the route control packet, and creates a route table to the base station 10. When the own node transmits a data packet, it performs multi-hop wireless transmission to the next transfer destination node using this routing table.

  Under the control of the isolation determining unit 106, the intercepting command unit 104b instructs the wireless signal receiving unit 102 and the data processing unit 103 to intercept the data packet transmitted by another node. As described later, the isolation determination unit 106 determines whether or not the own node has become an isolated node based on whether or not the route control packet has been received within the route construction period (that is, the adjacent node is ("0"). Then, the intercepting command unit 104b enables all data packets transmitted by other nodes to be received based on the determination result that the own node has been isolated by the isolation determining unit 106. In other words, a node that has become an isolated node can receive all receivable data packets including data packets addressed to other nodes.

  At this time, the network management unit 104 stores information on the transmission source node included in the data packet transmitted by the other node in the storage unit 105. Specifically, the information on the transmission source node is, for example, address information (for example, a MAC address or the like) of the transmission source node. When receiving the data packet transmitted by each of the plurality of other nodes, the network management unit 104 stores information on the transmission source node of each data packet in the storage unit 105. Thus, when the own node becomes an isolated node, the source node of the data packet that the own node can receive can be stored.

Various methods can be applied to the interception method by the interception instruction unit 104b as long as all receivable data packets can be received. For example, the intercepting command unit 104b may set the operation mode to a promiscuous mode (promiscuous mode). In a general wireless communication process, a packet addressed to the own node is received from the incoming packets and notified to a higher-level system. On the other hand, the promiscuous mode is an operation mode in which not only packets addressed to the own node but also all incoming packets including packets not addressed to the own node (addressed to other nodes) are received indiscriminately and notified to the upper system. It is . This Kodewa that although the case where the promiscuous mode, but is not limited thereto.

  The parent node determination unit 104c determines a parent node to which a data packet is to be transmitted. When a route control packet has been received within the route construction period, the parent node determination unit 104c determines a parent node based on the routing table. Further, when the route control packet cannot be received within the route construction period, the data packet transmitted by the other node can be intercepted, so that the parent node determining unit 104c determines the node address stored in the storage unit 105. The parent node is determined based on the information. The address information of the parent node determined by the parent node determination unit 104c is provided to the packet generation unit 108.

  The isolation determining unit 106 acquires information on the adjacent node obtained by the route construction processing by the network management unit 104, and determines whether the own node has become an isolated node.

  The isolation determining unit 106 determines that the own node is an isolated node when the number of adjacent nodes of the own node becomes “0” by the route construction processing, and otherwise determines that the own node is not an isolated node. More specifically, when no route control packet is received within the route construction period, the latest route table cannot be created, and the number of nodes adjacent to the own node becomes “0”. Therefore, the isolation node 106 may determine that the own node is an isolated node when no route control packet is received within the route construction period.

  The timer unit 107 counts a predetermined time under the control of the isolation determination unit 106. The timer unit 107 measures the time until the end time of the route construction time according to the instruction of the isolation determination unit 106, and notifies the isolation determination unit 106 of the timing end time after the completion of the time measurement. Similarly, the timer unit 107 measures the time until the start timing of the data transmission time of the own node according to the instruction of the isolation determination unit 106, and notifies the isolation determination unit 106 of the timing end timing after the completion of the time measurement.

  The packet generation unit 108 generates a data packet to be transmitted by the own node, and provides the data packet to the radio signal transmission unit 109. For example, when the own node transmits sensor data, the packet generation unit 108 acquires sensor data from the external system 111 functioning as a sensor, and generates a data packet including the sensor data. At this time, the packet generation unit 108 generates a packet with the address information of the parent node determined by the parent node determination unit 104c of the network management unit 104 as a transmission destination. Further, for example, when the own node functions as a multi-hop relay node, it acquires data to be relayed from the network management unit 104 and generates a packet including the relay data.

  Radio signal transmitting section 109 receives the packet data from packet generating section 108, performs modulation processing and the like, and provides the result to antenna section 110.

(A-2) Operation of Embodiment Next, the operation of the wireless communication process according to this embodiment will be described in detail with reference to the drawings.

  FIG. 3 is a diagram showing a node arrangement in the wireless communication system 1 according to this embodiment.

  As illustrated in FIG. 3, the wireless communication system 1 includes one base station (BS) 10 and five mobile stations 20-1 to 2-5 managed by the base station 10. .

  Hereinafter, for convenience of explanation, the mobile station 20-1 will be referred to as "node A" or the like, for example, using the alphabets shown in FIG.

  In FIG. 3, a solid line connecting the nodes indicates that the nodes at both ends of the straight line are in a communicable state, and a dotted line indicates that the nodes at both ends are within the connectable range, but during the route construction period. Indicates that communication was not possible.

  FIG. 4 is a flowchart showing a wireless communication process in the mobile station 20 according to this embodiment.

  The wireless communication system 1 employs a proactive routing protocol. It is assumed that the base station 10 periodically transmits a route control packet so that the route control packet is distributed to all the nodes A to E, and a network topology is constructed. In other words, it is assumed that a network topology has been established in each node until a data transmission request is generated. A period for constructing the network topology is called a route construction period. A period during which each node performs data transmission is called a data transmission period.

  When the route construction period starts, the isolation determining unit 106 sets a timer to notify the end of the route construction period (S101).

  When a route control packet is received from another node during the route construction period (S102, S103), the parent node is determined according to the routing algorithm, and the data packet is transmitted to the parent node. Specifically, in the network management unit 104, the route construction unit 104a creates a route table (S104). When data transmission occurs, the parent node determination unit 104c determines a parent node by referring to the routing table, and the packet generation unit 108 generates a data packet addressed to the determined parent node and transmits the data packet ( S105).

  When a route control packet is not received from another node during the route construction period, that is, when a route control packet is not received before the end timing notification of the route construction period is provided from the timer unit 107 to the isolation determination unit 106 (S102, S103), the isolation determination unit 106 determines that the own node is an isolated node, and the process proceeds to S106.

  For example, in FIG. 3, the node E exists in a connectable range with the node C or the node D. However, for example, when there is no reception of a route control packet within the route construction period, the node E is determined to be an isolated node because, for example, an obstacle exists between the nodes during the route construction period. You.

  When determining that the own node is an isolated node, the isolation determining unit 106 instructs the network management unit 104 to intercept data communication of another node. In response to this, the interception instruction unit 104b of the network management unit 104 instructs the wireless signal reception unit 102 to intercept the data communication of another node (S106).

  Here, in this embodiment, the period during which the data communication of the other node is intercepted is, for example, before the data transmission period of the own node. In other words, for example, each node continuously intercepts data communication until the data transmission period of the own node starts. Accordingly, in order to know the start timing of the data transmission period of the own node, the isolation determining unit 106 sets a timer until the start timing of the data transmission period of the own node (S107).

  The wireless signal receiving unit 102 receives (intercepts) a data signal transmitted from another node (S108), and a data packet from the other node is provided to the data processing unit 103. The data processing unit 103 analyzes the data packet of the other node, and gives information on the source node described in the data packet to the network management unit 104. The network management unit 104 stores the information on the source node in the storage unit. This is stored in the storage 105 (S109).

  Here, when intercepting a packet that is not addressed to its own node, generally, only the transceiver of the packet can often demodulate the packet due to security or other restrictions. However, in the multi-hop wireless communication system to which this embodiment is applied, for example, information of an APL (application) layer is encrypted, but information of an NWK (network) layer is not encrypted and belongs to the same network. It is assumed that a node that is capable of intercepting packets and collecting information necessary for network management, such as enabling demodulation of packets up to the NWK layer, is possible. Therefore, the data processing unit 103 can extract information on the source node described in the received packet.

  For example, in the example of FIG. 3, it is assumed that the nodes C and D have transmitted data packets before the start of the data transmission period of the node E. In this case, since the node E exists within the transmission range of the nodes C and D, the node E can intercept the data packets of the nodes C and D.

  For example, the data packet of the node C includes the address information of the node C as information about the source node, and the information about the destination node includes the address information of the base station 10 as the final destination. I have. Although the data packet of the node C is not destined for the node E, the data processing unit 103 of the node E does not discard the data packet of the node C, but rather, discards the network information (that is, the transmission source) included in the data packet. The address information of the node C, which is information on the node, is extracted, and the network information is provided to the network management unit 104. The same applies to the data packet of the node D.

  When the isolation determining unit 106 receives the notification of the start timing of the data transmission period of the own node from the timer unit 107, the isolation determining unit 106 instructs the network management unit 104 to determine the parent node. In response to this, in the network management unit 104, the parent node determination unit 104c determines the parent node with reference to the information on the source node of the data packet of the other node stored in the storage unit 105 (S111). .

  The packet generation unit 108 generates a data packet with the address information of the parent node determined by the parent node determination unit 104c as a transmission destination, and transmits the data packet to the parent node (S112).

  For example, in the case of the example of FIG. 3, the storage unit 105 stores the address information of the node C and the address information of the node D. Therefore, the parent node determination unit 104c determines either the node C or the node D as a parent node, and provides the address information of the parent node to the packet generation unit 108. As a result, the node E can transmit a data packet to either the node C or the node D. As a result, the data packet of the node E is transmitted by multi-hop communication to the base station 10 via either the node C or the node D.

  Here, the radio signal receiving unit 102 of the node E can continuously intercept the data packet until the data transmission period of the node E comes. Therefore, it is possible to intercept data packets from a plurality of adjacent nodes, and to store information (address information of adjacent nodes) on a plurality of transmission source nodes that have been successfully received.

  In such a case, the parent node determination unit 104c selects any of the information on the plurality of transmission source nodes as the parent node. Various indexes (metrics) related to the selection of the parent node can be applied.

  For example, the received signal strength of the packets received from the nodes C and D may be used as the metric. Specifically, a node having a high received signal strength may be set as the parent node. A high received signal strength, for example, often means that the distance to another node is short, and that the communication quality with the other node is good. Therefore, in order to transmit a data packet with good communication quality, the parent node determining unit 104c can select, as the parent node, information having a higher received signal strength from among information on a plurality of transmission source nodes. Further, for example, a packet whose arrival time at the node E is earlier may be set as the parent node.

  As described above, each node can transmit a data packet to the determined parent node at the timing of the data transmission period of the own node in the data communication period.

(A-3) Effects of the Embodiment As described above, according to this embodiment, even when an isolated node occurs, the control packet for the isolated node is not exchanged between the nodes, or The transmission of the data packet of the isolated node can be realized without preparing the time for requesting the retransmission of the node.

  That is, if an isolated node occurs and the isolated node is not rescued, the data collection rate in the base station will decrease, but the data collection rate can be improved without imposing a load on the network.

  In a network that implements a method that requires a control packet for an isolated node, nodes other than the isolated node also need to perform control for the isolated node. Therefore, the power of the node is consumed, the operating time of the node is shortened, and the life of the network is shortened.

  However, according to this embodiment, since it is not necessary to exchange control packets for isolated nodes between the nodes, power consumption of each node other than the isolated nodes can be suppressed, and node operating time can be secured. It is possible to extend the life of nodes and networks.

  Furthermore, according to this embodiment, the route construction period and the data communication period can be set longer as compared with a network in which a conventional isolated node countermeasure system is provided with a time for requesting retransmission of an isolated node. As a result, the number of accommodated nodes can be increased.

(B) Other Embodiments Although various modified embodiments have been described in the above-described embodiments, the present invention is also applicable to the following modified embodiments.

  (B-1) In the above-described embodiment, a case has been exemplified in which a network including a route construction period and a data communication period is adopted as a network applied to the present invention. However, in order to apply the present invention, the network does not necessarily have to be that type of network, and any network may be used as long as a route is established and another node performs data communication before the start timing of the data transmission period of the own node.

  (B-2) In the above-described embodiment, the operation in the case where the packet of another node has been successfully intercepted during the data communication period has been described. However, if the interception of the packet fails, the network topology may be considered as unchanged and may be sent to the parent node at the time of the previous transmission. Specifically, in S107 of FIG. 4, when the data signal of the other node cannot be received during the interception operation, the parent node determining unit 104c sets the node that transmitted the data packet immediately before or in the past as the parent node. It may be determined.

  (B-3) In the above-described embodiment, the operation of intercepting a packet of another node from the end of the route construction period to the start timing of the data transmission period of the own node has been described. However, between the time after the transmission of the own node data and the start of the next route construction period, the packet of another node may be intercepted and set as a candidate for the parent node of the next data packet transmission.

  (B-4) In the above-described embodiment, the present invention is applied to a specific node. However, the present invention may be applied to all nodes participating in a target multi-hop wireless network.

DESCRIPTION OF SYMBOLS 1 ... Wireless communication system, 10 ... Base station, 20 (20-1 to 20-5) ... Mobile station,
REFERENCE SIGNS LIST 100 wireless communication apparatus 101 antenna unit 102 wireless signal receiving unit 103 data processing unit 104 network management unit 105 storage unit 106 isolation determining unit 106 timer unit 108 packet generating unit , 109: a radio signal transmission unit, 110: an antenna unit, 104a: a route construction unit, 104b: an interception command unit, 104c: a parent node determination unit.

Claims (7)

Information of the application layer is encrypted, the communication signal following layer information network Leia unencrypted, to the base station, a wireless communication device for each node in the multi-hop wireless communication system for wireless communication in a multi-hop So ,
Wireless receiving means;
A network management unit that creates a routing table based on information included in a routing control signal received within a predetermined routing period, determines a parent node, and performs a wireless communication process ;
Wireless transmission means for transmitting the communication signal addressed to the parent node determined by the network management means ,
An isolation determining unit that determines whether the own node is an isolated node, depending on whether the route control signal is received within the route construction period ,
The above network management means,
When the isolation node determines that the own node is an isolated node, a timer is set for a predetermined interception period until the start of the transmission period of the own node. An interception command unit that issues a command to intercept all the communication signals that can be received, including
A parent node determining unit that determines a parent node based on source information of the communication signal received by the wireless reception unit during the interception period;
Radio communication apparatus characterized by having a. Said master node determining unit, based on information about the source node included in the received the communication signal by the radio reception means, according to claim 1, characterized in that to determine the source node as a parent node A wireless communication device according to claim 1. The network management unit stores information on each of the transmission source nodes of the one or more communication signals that has been successfully intercepted by the wireless reception unit, as a parent node candidate,
The parent node determination unit determines a parent node of the communication signal transmitted by the own node from one or a plurality of parent node candidates,
The wireless transmission means, wireless communication apparatus according to claim 1 or 2, characterized in that transmits the communication signal addressed to the parent node determined by the parent node determining unit. When the interception by the wireless reception unit fails, the parent node determination unit refers to the routing table, and as the parent node used for transmitting the communication signal of the own node in the past,
The wireless communication device according to any one of claims 1 to 3 , wherein the wireless transmission unit transmits the communication signal addressed to the parent node determined by the parent node determination unit. Said network management unit, a period of from after the end of the route construction period until the start of the communication signal transmission period of its own node, and or, from after completion of the communication signal transmission period of its own node to the start of the next route construction period The wireless communication device according to any one of claims 1 to 4 , wherein the wireless communication device is intercepted during the period. The information of the application layer is encrypted, and the layer information below the network layer is used in a wireless communication program of each node of the multi-hop wireless communication system that wirelessly communicates the unencrypted communication signal to the base station in a multi-hop manner . ,
Computer
Wireless receiving means;
A network management unit that creates a routing table based on information included in a routing control signal received within a predetermined routing period, determines a parent node, and performs a wireless communication process ;
Wireless transmission means for transmitting the communication signal addressed to the parent node determined by the network management means ,
Depending on the presence or absence of reception of the path control signal in the route construction period, the own node so that functions as the isolation determination means that determines whether an isolated node,
The above network management means,
When the isolation node determines that the own node is an isolated node, a timer is set for a predetermined interception period until the start of the transmission period of the own node. An interception command unit that issues a command to intercept all the communication signals that can be received, including
A parent node determining unit that determines a parent node based on source information of the communication signal received by the wireless reception unit during the interception period;
A wireless communication program characterized by functioning as: The information of the application layer is encrypted, and the layer information below the network layer is used in the wireless communication method of each node of the multi-hop wireless communication system in which the unencrypted communication signal is wirelessly communicated in multiple hops toward the base station . ,
A network management unit that creates a routing table based on information included in a routing control signal received within a predetermined routing period, determines a parent node, performs wireless communication processing ,
Wireless transmitting means for transmitting the communication signal addressed to the parent node determined by the network management means ,
Isolation determining means determines whether or not the own node is an isolated node, depending on whether or not the route control signal has been received within the route construction period,
The above network management means,
When the isolation node determines that the own node is an isolated node, a timer is set for a predetermined interception period until the start of the transmission period of the own node. Command to intercept all the communication signals that can be received, including
A wireless communication method comprising: determining a parent node based on transmission source information of the communication signal received by the wireless reception unit during the interception period .

Images