COMMUNICATION METHOD, COMMUNICATION SYSTEM, AND COMMUNICATION DEVICE

Abstract

To provide a technology enabling routing construction for stable data communication in a communication network.SOLUTION: A communication method to be executed by a first communication apparatus having a first identifier includes: receiving, at a first frequency, a connection request signal that is transmitted by a second communication apparatus having a second identifier and includes the second identifier; on the basis of comparison between the first identifier and the second identifier, determining whether or not the first communication apparatus is a manager for managing data transmission of the second communication apparatus; and, when it is determined that the first communication apparatus is the manager, transmitting, at the first frequency, a connection response signal including frequency information showing a second frequency that differs from the first frequency and is to be used for the data transmission.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] FIELD OF THE INVENTION Embodiments of the present invention relate to a communication method, a communication system, and a communication device. [Background technology]

[0002] In wireless networks such as autonomous distributed wireless networks, there is a concern that unwanted electromagnetic interference may affect communication media such as desired wireless communications, resulting in communication failures. To address this issue, it has been proposed to use multipath network transmission paths so that the network can be maintained even if a communication failure occurs partially.

[0003] In an autonomous distributed wireless network, all wireless devices generally communicate data based on the same algorithm for determining transmission power, transmission frequency, and transmission timing. In an autonomous distributed wireless network with multipath transmission paths, a large number of wireless hops are possible, but the traffic volume is expected to increase, making routing difficult. Furthermore, the transmission state of the communication path between wireless devices is unstable, and data communication that cannot be corrected for errors may require a retransmission request. Frequent data retransmission requests place a heavy load on the network.

[0004] In communication networks such as wireless networks, there is a demand for efficient routing construction that ensures stable data communication. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2019-153990 Summary of the Invention [Problem to be solved by the invention]

[0006] The problem to be solved by the present invention is to provide a technique that enables the construction of routing that ensures stable data communication in a communication network. [Means for solving the problem]

[0007] In one embodiment, a communication method performed by a first communication device having a first identifier comprises receiving, at a first frequency, a connection request signal transmitted by a second communication device having a second identifier and including the second identifier; determining whether the first communication device is an administrator that manages data transmission of the second communication device based on a comparison between the first identifier and the second identifier; and, if it is determined that the first communication device is the administrator, transmitting, at the first frequency, a connection response signal including frequency information indicating a second frequency to be used for the data transmission, the second frequency being different from the first frequency. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing a wireless system according to an embodiment. [Figure 2] FIG. 2 is a diagram showing the hardware configuration of a wireless device according to an embodiment. [Figure 3] 3 is a diagram showing the configuration of a transmission circuit included in the communication module shown in FIG. 2. [Figure 4] FIG. 2 is a block diagram showing the functional configuration of a wireless device according to the embodiment. [Figure 5] FIG. 5 is a block diagram showing the configuration of a communication control unit shown in FIG. [Figure 6] 10 is a flowchart showing a call process according to the embodiment. [Figure 7] FIG. 2 is a diagram showing a call sequence according to the embodiment. [Figure 8] FIG. 2 is a diagram showing a call sequence according to the embodiment. [Figure 9] 10 is a flowchart showing a data transmission process according to the embodiment. [Figure 10] 10 is a flowchart showing a data transmission process according to the embodiment. [Figure 11]FIG. 2 is a diagram showing a data transmission sequence according to the embodiment. [Figure 12] FIG. 2 is a diagram showing a data transmission sequence according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described with reference to the drawings. In order to avoid repetition of explanation, similar components are designated by similar reference numerals throughout the drawings. In addition, in some drawings, subscripts are added to the reference numerals to distinguish individual components.

[0010] FIG. 1 schematically illustrates a wireless system 10 according to one embodiment. The wireless system 10 illustrated in FIG. 1 is a wireless ad-hoc network constructed by a plurality of nodes 14, each of which communicates wirelessly directly with surrounding nodes 14. In the wireless system 10, data communication is performed by broadcast. The nodes 14 are wireless devices such as special-purpose radios and mobile communication terminals (e.g., smartphones). In the embodiment described herein, a mobile object known as a drone will be described as an example of a node.

[0011] In the wireless system 10, information such as location information is shared among the nodes 14, and each node 14 moves autonomously based on the shared information so that the network transmission paths are multipath. In this way, a distributed wireless network with multipath transmission paths is constructed.

[0012] The topology of the wireless system 10 changes over time. For example, one of the nodes 14 may leave the wireless system 10 due to movement or failure. Also, a new node 14 may be deployed and join the wireless system 10.

[0013] The wireless system 10 may include multiple wireless networks 12 (three wireless networks 12 in the example of FIG. 1). The terms "system" and "network" are used interchangeably herein. When the wireless system 10 is referred to as a wireless network, the wireless networks 12 may be referred to as wireless subnetworks, etc.

[0014] Each wireless network 12 includes one node 14 that acts as a master (administrator) that manages data transmission in that wireless network 12, and one or more nodes 14 that act as slaves that transmit data under the control of the master. Hereinafter, a node that acts as a master may be referred to as a master node, and a node that acts as a slave may be referred to as a slave node.

[0015] Each node 14 is assigned a unique identifier (hereinafter referred to as a unique ID). For example, the unique ID may be an identifier prepared for the wireless system 10. The unique ID may be, for example, a media access control (MAC) address of a wireless module included in the node. In the embodiment described here, a node 14 with a smaller unique ID has the authority to become an administrator. In this case, in each wireless network 12, the master node 14 has a unique ID that is smaller than the unique ID of each of the slave nodes 14. In other embodiments, a node 14 with a larger unique ID may have the authority to become an administrator. Note that a node 14 may be a master in one wireless network 12 and a slave in another wireless network 12.

[0016] Assume that the first node 14 does not have a data link, and that the second node 14 is located near the first node 14. Here, the data link indicates a master-slave relationship between nodes. The first node 14 periodically issues a call (connection request). Specifically, the first node 14 periodically transmits (broadcasts) a connection request packet requesting the establishment of a data link. The connection request packet includes the unique ID of the first node 14. The second node 14 receives the connection request packet transmitted by the first node 14 and compares its own unique ID with the unique ID contained in the connection request packet. If the second node 14's own unique ID is smaller than the unique ID contained in the connection request packet, the second node 14 recognizes that the second node 14 is the administrator of the wireless network 12 including the first node 14 and the second node 14, i.e., the second node 14 is the administrator that manages data transmission by the first node 14. The second node 14 transmits a connection response packet in response to the connection request packet. The connection response packet includes the unique ID of the second node 14, the unique ID of the first node 14, and frequency information indicating the frequency to be used for data communication. The first node 14 receives the connection response packet transmitted by the second node 14. As a result, a data link is established between the first node 14 and the second node 14, with the second node 14 being the master and the first node 14 being the slave.

[0017] In the embodiment described here, only the master node and nodes without a data link make calls autonomously, and slave nodes do not make calls autonomously.

[0018] In the wireless system 10, data communication is performed at a frequency different from that used for calling. Hereinafter, the frequency used for calling is referred to as the calling frequency, and the frequency used for data communication is referred to as the data frequency.

[0019] The master node 14 schedules data transmission in the wireless network 12 and transmits a scheduling packet. Data transmission in the wireless network 12 is based on the TDMA (Time Division Multiple Access) method. Each slave node 14 determines its own transmission timing based on the scheduling packet transmitted by the master node 14, and transmits a data packet at the determined transmission timing.

[0020] The node 14 can switch between short-range communication, in which it transmits at low transmission power, and long-range communication, in which it transmits at high transmission power. For example, the master node 14 may use short-range communication to transmit to slave nodes 14 in its own wireless network 12 and long-range communication to transmit to master nodes 14 in other wireless networks 12.

[0021] When adjacent wireless networks 12 are small (for example, when the number of nodes belonging to each wireless network 12 is below a predetermined threshold), the master nodes 14 of these wireless networks 12 may coordinate to perform scheduling so that the data frequencies of these wireless networks 12 are the same and all nodes belonging to these wireless networks 12 are scheduled.

[0022] According to the wireless system 10 having the above-described configuration, routing becomes easy. This reduces the load on network management. Furthermore, the overall data traffic volume is reduced. As a result, it becomes possible to establish routing that ensures stable data communication.

[0023] 2 to 5, a wireless device corresponding to one of the nodes 14 shown in Figure 1 will be described. The other nodes 14 shown in Figure 1 may have the same or similar configuration as that described in connection with Figures 2 to 5.

[0024] 2 schematically illustrates an example of the hardware configuration of a wireless device 100 according to an embodiment. As illustrated in FIG. 2, the wireless device 100 includes, as hardware components, a main body 101, a mobile device 102, a processor 103, a memory 104, a wireless module 105, an observation device 106, a gyro sensor 107, and a satellite positioning system such as a GPS (Global Positioning System) device 108. The wireless device 100 further includes a battery (not shown) that supplies power to the mobile device 102, the processor 103, the memory 104, the wireless module 105, the observation device 106, the gyro sensor 107, and the GPS device 108.

[0025] The main body 101 houses a mobile device 102, a processor 103, a memory 104, a wireless module 105, an observation device 106, a gyro sensor 107, a GPS device 108, and a battery.

[0026] The mobile device 102 is a device that enables the movement and change of attitude of the wireless device 100. As an example, the mobile device 102 includes a plurality of propellers and a plurality of motors that rotate the plurality of propellers.

[0027] The processor 103 is electrically connected to and controls the mobile device 102, memory 104, wireless module 105, observation device 106, gyro sensor 107, GPS device 108, and battery. The processor 103 is a general-purpose circuit such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit).

[0028] The memory 104 stores a control program and data. The control program includes a plurality of computer-executable instructions. When executed by the processor 103, the control program causes the processor 103 to perform a series of processes described below.

[0029] The processor 103 may be a dedicated circuit configured to perform a series of processes described below, such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array).

[0030] The wireless module 105 includes a circuit for transmitting and receiving wireless signals. The observation device 106 is a directional observation device such as a camera, radio wave radar, or laser radar, and observes an observation target in the direction of its direction to obtain observation information (e.g., image data). The gyro sensor 107 and GPS device 108 are used to detect the position and attitude of the wireless device 100.

[0031] Fig. 3 shows a schematic configuration example of the transmission circuit 110 included in the wireless module 105. A part of the transmission circuit 110 is shown in Fig. 3. As shown in Fig. 3, the transmission circuit 110 includes four slots 111-1 to 111-4 arranged in parallel, and a combining circuit 112 connected to the slots 111-1 to 111-4.

[0032] Each of the slots 111-1 to 111-4 corresponds to an analog-to-digital converter (ADC), which modulates a carrier wave with a packet (digital signal) to be transmitted to generate a modulated wave. Each of the slots 111-1 to 111-4 can switch the frequency of the carrier wave between two or more frequencies (for example, 16 frequencies F0 to F15).

[0033] Combining circuit 112 combines the modulated waves output from slots 111-1 to 111-4 to generate a composite modulated wave. The composite modulated wave output from combining circuit 112 is radiated as a radio signal from an antenna (not shown) connected to radio module 105.

[0034] In the embodiment described here, it is assumed that slots 111-1 and 111-2 are used for calling, and slots 111-3 and 111-4 are used for data transmission. Furthermore, it is assumed that frequencies F0 and F1 are used for calling, and frequencies F2 to F15 are used for data communication.

[0035] The transmitting circuit 110 may use one slot for short-distance communication and two slots for long-distance communication. For example, the same frequency (e.g., frequency F0) is set to slots 111-1 and 111-2, and the same packet is input to slots 111-1 and 111-2. In this case, the modulated waves output from slots 111-1 and 111-2 will be the same. The modulated waves output from slots 111-1 and 111-2 are combined by the combining circuit 112, and as a result, the radio signal carrying the packet is transmitted at high power.

[0036] Fig. 4 schematically illustrates an example of a functional configuration of the wireless device 100 according to the embodiment. As illustrated in Fig. 4, the wireless device 100 includes a transmitter 151, a receiver 152, a communication controller 153, a memory 154, and a data processor 155. The transmitter 151 and the receiver 152 may be implemented by the wireless module 105. The communication controller 153 may be implemented by the wireless module 105, the processor 103, or a combination of the wireless module 105 and the processor 103. The data processor 155 may be implemented by the processor 103. The memory 104 may be implemented by the memory 104.

[0037] Transmitting unit 151 wirelessly transmits (broadcasts) packets such as connection request packets, connection response packets, data packets, etc. Communication control unit 153 controls packet transmission by transmitting unit 151. Communication control unit 153 will be described later with reference to FIG.

[0038] Receiving unit 152 receives packets transmitted by other nodes (other wireless devices). The data packets received by receiving unit 152 are temporarily stored in storage unit 154 and sent to data processing unit 155. Data processing unit 155 extracts data from the data packets received by receiving unit 152. The data includes, for example, location information of other nodes and / or observation information obtained by other nodes.

[0039] Data processing unit 155 generates a data packet containing data to be transmitted as a payload. The data to be transmitted includes, for example, location information of wireless device 100 and / or observation information obtained by observation device 106. The data to be transmitted may also include information related to other nodes obtained from the data packet received by receiver 152. The data packet generated by data processing unit 155 is temporarily stored in storage unit 154 and transmitted by transmitter 151 at a timing determined by communication control unit 153.

[0040] 5 shows a schematic configuration example of the communication control unit 153. As shown in FIG. 5, the communication control unit 153 includes a transmission control unit 161, a classification unit 162, a determination unit 163, an allocation unit 164, a management unit 165, and a scheduling unit 166.

[0041] The classification unit 162 classifies packets received by the receiving unit 152. Packet types include, for example, data packets, connection request packets, connection response packets, scheduling packets, and release packets. Type information indicating the packet type is stored, for example, in the packet header. The classification unit 162 classifies packets based on the type information included in the packet header. If the received packet (a packet received by the receiving unit 152) is a data packet, the classification unit 162 sends the received packet to the storage unit 154. If the received packet is a connection request packet, the classification unit 162 sends the received packet to the determination unit 163. If the received packet is a connection response packet, scheduling packet, or release packet, the classification unit 162 sends the received packet to the management unit 165.

[0042] The determination unit 163 determines whether the wireless device 100 is an administrator that manages data transmission of the node that transmitted the connection request packet based on a comparison between the unique ID of the wireless device 100 and the unique ID included in the connection request packet, and sends the determination result to the management unit 165. If the unique ID of the wireless device 100 is smaller than the unique ID included in the connection request packet, the determination unit 163 determines that the wireless device 100 is an administrator. The determination unit 163 notifies the allocation unit 164 that it has determined that the wireless device 100 is an administrator. If the unique ID of the wireless device 100 is larger than the unique ID included in the connection request packet, the determination unit 163 determines that the wireless device 100 is not an administrator, and that the node that transmitted the connection request packet is an administrator that manages data transmission of the wireless device 100.

[0043] Upon receiving the notification from the determination unit 163, the allocation unit 164 allocates a data frequency to the node that transmitted the connection request packet and sends the allocation result to the management unit 165. The allocation unit 164 allocates any one of the data frequencies F2 to F15 to the node that transmitted the connection request packet. As an example, the allocation unit 164 may select a relatively idle data frequency as the data frequency to be allocated to the node that transmitted the connection request packet. For example, the allocation unit 164 observes the usage status of the data frequencies F2 to F15 by the other wireless network 12 and obtains the usage frequency for each of the data frequencies F2 to F15. The allocation unit 164 may select the data frequency with the lowest usage frequency or a data frequency below a predetermined threshold from among the data frequencies F2 to F15. The threshold value may be a fixed value or a variable value such as the average value of the usage frequencies of the data frequencies F2 to F15. As an alternative, the allocation unit 164 may select the data frequency with the lowest usage frequency from among the data frequencies used by the wireless device 100. For example, if the data frequency F2 is set in slot 111-3, the data frequency F3 is set in slot 111-4, the usage frequency of the data frequency F2 by the other wireless network 12 is M, and the usage frequency of the data frequency F3 by the other wireless network 12 is N (M < N), the allocation unit 164 allocates the data frequency F2 to the node that transmitted the connection request packet. By allocating a relatively idle data frequency, the possibility of overreach interference can be reduced.

[0044] The management unit 165 manages the data link. The management unit 165 holds a data table in which the unique ID of the node with which the data link is established is associated with information indicating whether it is a master or a slave and information indicating the data frequency.

[0045] When the receiver 152 receives the connection request packet and the determiner 163 determines that the wireless device 100 is the administrator, the manager 165 adds an entry to the data table, the entry including the unique ID included in the connection request packet, information indicating that the wireless device 100 is a slave, and information indicating the data frequency assigned by the assigner 164. The node that sent the connection request packet is added to the wireless network 12 in which the wireless device 100 operates as a master.

[0046] When the receiving unit 152 receives a connection response packet, the management unit 165 adds an entry to the data table, the entry including the unique ID of the node that sent the connection response packet, information indicating that it is the master, and information indicating the data frequency indicated by the frequency information included in the connection response packet.

[0047] When the receiver 152 receives a scheduling packet, the manager 165 determines whether or not the unique ID of the wireless device 100 is included in slave information (described later) included in the scheduling packet. If the unique ID of the wireless device 100 is included in the slave information included in the scheduling packet, the manager 165 transfers the scheduling packet to the transmission controller 161.

[0048] When the receiving unit 152 receives the release packet, the management unit 165 determines whether the unique ID included in the release packet is the same as the unique ID of the wireless device 100. If the unique ID included in the release packet is the same as the unique ID of the wireless device 100, the management unit 165 deletes the entry corresponding to the master node that transmitted the release packet from the data table. The wireless device 100 leaves the wireless network 12 of the master node that transmitted the release packet.

[0049] Furthermore, if the receiving unit 152 does not receive a scheduling packet from the master node for a predetermined period of time, the management unit 165 determines that the data link has been disconnected, and deletes the entry corresponding to the master node from the data table.

[0050] The scheduling unit 166 schedules data transmission in the wireless network 12. Data transmission in the wireless network 12 is based on the TDMA method. The scheduling unit 166 determines a transmission cycle for switching the node that performs data transmission, depending on the number of nodes that belong to the wireless network 12 in which the wireless device 100 operates as a master. For example, the scheduling unit 166 determines the transmission cycle so that the transmission cycle becomes shorter as the number of nodes increases.

[0051] When there are multiple data frequencies, the scheduling unit 166 schedules data transmission for each data frequency. For example, when scheduling data transmission using data frequency F2 in the wireless network 12, the scheduling unit 166 determines the transmission period depending on the number of nodes included in the wireless network 12 and assigned data frequency F2.

[0052] The transmission control unit 161 transmits packets such as data packets via the transmitting unit 151. When the scheduling unit 166 determines the transmission period, the transmission control unit 161 generates and transmits a scheduling packet including the unique ID of the wireless device 100, the transmission period determined by the scheduling unit 166, and slave information indicating nodes that can transmit data. The slave information includes the unique IDs of the nodes that can transmit data. The slave information may further include information indicating an allocation number, which is the number of nodes that can transmit data.

[0053] When the receiving unit 152 receives a scheduling packet, the transmission control unit 161 determines the transmission timing of the wireless device 100 based on the scheduling packet and transmits data packets at the determined transmission timing. For example, the transmission control unit 161 determines the order in which the wireless device 100 will transmit data based on the unique IDs of nodes that can transmit data, which are included in the scheduling packet. Specifically, the transmission control unit 161 determines the transmission order based on the largest unique ID of the wireless device 100 among the unique IDs included in the scheduling packet. In the embodiment described here, the smaller the unique ID, the earlier the transmission order. For example, if the unique ID of the wireless device 100 is the smallest among the unique IDs included in the scheduling packet, the transmission control unit 161 recognizes that the transmission order of the wireless device 100 is first. The transmission control unit 161 calculates the transmission timing based on the transmission period included in the scheduling packet and the transmission order of the wireless device 100.

[0054] If wireless device 100 does not have a data link, transmission control unit 161 periodically transmits a connection request packet. If wireless device 100 does not have a data link for a predetermined period of time, transmission control unit 161 transmits a connection request packet using long-distance communication.

[0055] The transmission control unit 161 transmits a release packet to the node where the data transmission has become abnormal, instructing the node to release the data link. The release packet includes the unique ID of the node where the data transmission has become abnormal.

[0056] If there are many wireless devices in close proximity, the network will become saturated. Therefore, if it is determined that a data link cannot be established at the calling frequency F0 and the transmission power of the other wireless device is high, the transmission control unit 161 changes the calling frequency F1 from normal mode to weak mode, which has weaker transmission power, and performs calls using only the calling frequency F1 for a specified period of time. However, communication between administrators uses the calling frequency F0.

[0057] Next, the operation of the wireless system 10 will be described.

[0058] Fig. 6 shows an example of a procedure for call processing executed by the wireless device 100 shown in Fig. 5. Here, a case where the wireless device 100 receives a connection request from another wireless device will be described. A wireless device that does not have a data link and makes a connection request is called a target wireless device.

[0059] 6, the receiver 152 receives a connection request packet transmitted by the target wireless device on the calling frequency. The connection request packet includes the unique ID of the target wireless device.

[0060] In step S12, the decision unit 163 compares the unique ID of the wireless device 100 with the unique ID of the target wireless device contained in the received connection request packet.

[0061] If the unique ID of wireless device 100 is smaller than the unique ID of the target wireless device (step S12; Yes), the process proceeds to step S13. In step S13, determination unit 163 determines that wireless device 100 is an administrator that manages data transmission of the target wireless device. Specifically, determination unit 163 determines that wireless device 100 is an administrator that manages data transmission in the wireless network including wireless device 100 and the target wireless device.

[0062] In step S14, the allocation unit 164 allocates a data frequency to the target wireless device. For example, the allocation unit 164 allocates a relatively vacant data frequency to the target wireless device.

[0063] In step S15, transmitter 151 transmits a connection response packet in response to the connection request packet on the call frequency. The connection response packet includes the unique ID of wireless device 100, the unique ID of the target wireless device, and frequency information indicating the data frequency assigned to the target wireless device. As a result, a data link is established between wireless device 100 and the target wireless device, with wireless device 100 acting as the master and the target wireless device acting as the slave.

[0064] If the unique ID of wireless device 100 is greater than the unique ID of the target wireless device (step S12: No), the process proceeds to step S16. In step S16, determination unit 163 determines that the target wireless device is an administrator that manages data transmission of wireless device 100. Specifically, determination unit 163 determines that the target wireless device is an administrator that manages data transmission in the wireless network that includes wireless device 100 and the target wireless device.

[0065] In step S17, transmitter 151 transmits a connection request packet including the unique ID of wireless device 100 at the calling frequency. The target wireless device receives the connection request packet transmitted by wireless device 100 and determines that the target wireless device is an administrator that manages data transmissions of wireless device 100. The target wireless device assigns a data frequency to wireless device 100 and transmits a connection response packet including frequency information indicating the assigned data frequency at the calling frequency. In step S18, receiver 152 receives the connection response packet transmitted by the target wireless device at the calling frequency. As a result, a data link is established between wireless device 100 and the target wireless device, with wireless device 100 being the slave and the target wireless device being the master.

[0066] In step S15 or step S17, the transmitter 151 may transmit a connection response packet or a connection request packet after waiting a time calculated based on the difference between the unique ID of the wireless device 100 and the unique ID of the target wireless device. For example, in step S15, the transmission controller 161 calculates a wait time based on the difference obtained by subtracting the unique ID of the target wireless device from the unique ID of the wireless device 100, and transmits the connection response packet when the wait time has elapsed since the target wireless device completed transmission of the connection request packet. For example, the smaller the difference, the shorter the wait time. If there are multiple wireless devices around the target wireless device, packet collisions will occur if the multiple wireless devices simultaneously transmit packets (connection response packets or connection request packets) in response to the connection request of the target wireless device. By transmitting packets after waiting a time calculated based on the difference between the unique ID of the wireless device 100 and the unique ID of the target wireless device, such packet collisions can be avoided or suppressed.

[0067] The target wireless device may receive connection response packets from multiple wireless devices. In one embodiment, the target wireless device may select the wireless device with the smallest unique ID from among the wireless devices that have transmitted the connection response packets, and transmit a confirmation packet on the calling frequency indicating that the selected wireless device will become the manager. The confirmation packet includes the unique ID of the target wireless device and the unique ID of the selected wireless device. This establishes a data link between the target wireless device and the wireless device selected by the target wireless device as the manager. In this embodiment, the wireless device may perform frequency allocation after being selected as the manager by the target wireless device (i.e., after receiving the confirmation packet).

[0068] 7 is a schematic diagram showing a call sequence when the unique ID of wireless device A is larger than the unique ID of wireless device B. As shown in FIG. 7, wireless device A transmits a connection request packet including its unique ID.

[0069] Wireless device B receives the connection request packet transmitted by wireless device A. Wireless device B acquires the unique ID of wireless device A, which is the sender of the connection request packet, from the received packet and compares the unique ID of wireless device B with the unique ID of wireless device A. Wireless device B recognizes that the unique ID of wireless device B is smaller than the unique ID of wireless device A and determines that wireless device B is the administrator of the wireless network including wireless devices A and B. Wireless device B determines the data frequency to be assigned to wireless device A. Wireless device B transmits a connection response packet including the unique ID of wireless device B, the unique ID of wireless device A, and frequency information indicating the determined data frequency. Wireless device B shifts to the data frequency determined by itself. For example, wireless device B sets the slot used for data transmission included in the transmission circuit (e.g., slot 111-3 shown in FIG. 3) to the data frequency determined by itself.

[0070] Wireless device A receives the connection response packet transmitted by wireless device B. Wireless device A shifts to the data frequency indicated by the frequency information included in the received connection response packet.

[0071] 8 is a schematic diagram showing a call sequence when the unique ID of wireless device A is smaller than the unique ID of wireless device B. As shown in FIG. 8, wireless device A transmits a connection request packet including its unique ID.

[0072] Wireless device B receives the connection request packet transmitted by wireless device A. Wireless device B obtains the unique ID of wireless device A, the sender of the received connection request packet, from the packet and compares the unique ID of wireless device B with the unique ID of wireless device A. Wireless device B recognizes that the unique ID of wireless device B is larger than the unique ID of wireless device A and determines that wireless device A is the administrator that manages data transmissions of wireless device B. Wireless device B transmits a connection request packet including the unique ID of wireless device B.

[0073] Wireless device A receives a connection request packet sent by wireless device B. Wireless device A determines that wireless device A is the administrator managing data transmission for wireless device B, and determines a data frequency to allocate to wireless device B. Wireless device A transmits a connection response packet including the unique ID of wireless device A, the unique ID of wireless device B, and frequency information indicating the determined data frequency. Wireless device A shifts to the data frequency it has determined. Wireless device B receives the connection response packet sent by wireless device A. Wireless device B shifts to the data frequency indicated by the frequency information included in the received connection response packet.

[0074] Fig. 9 schematically illustrates an example method for transmitting data in a wireless network, performed by wireless device 100 shown in Fig. 5. The flow illustrated in Fig. 9 is performed when wireless device 100 operates as a master node.

[0075] 9, the scheduling unit 166 schedules data transmission in the wireless network. For example, the scheduling unit 166 identifies nodes belonging to the wireless network in which the wireless device 100 operates as a master as nodes capable of transmitting data, and determines a transmission cycle according to the number of nodes capable of transmitting data. The transmission control unit 161 generates a scheduling packet including the transmission cycle determined by the scheduling unit 166 and the unique IDs of the nodes identified by the scheduling unit 166 to be capable of transmitting data.

[0076] In step S22, the transmitter 151 transmits, at the data frequency, the scheduling packet generated by the transmission controller 161. Each of the nodes identified as nodes capable of transmitting data transmits data in accordance with the scheduling packet.

[0077] In step S23, the management unit 165 determines whether the data transmission was successful. For example, the management unit 165 determines whether the receiving unit 152 was able to receive data packets from all nodes to which data can be transmitted. The management unit 165 determines that the data transmission was successful if the receiving unit 152 was able to receive data packets from all nodes, and determines that the data transmission was abnormal if the receiving unit 152 was unable to receive a data packet from any node. If the data transmission was successful (step S23; No), the process ends.

[0078] If there is a node whose data transmission was abnormal (step S23; Yes), the process proceeds to step S24. In step S24, the transmission control unit 161 generates a release packet including the unique ID of the node whose data transmission was abnormal, and transmits the packet at the data frequency.

[0079] Fig. 10 schematically illustrates an example method for transmitting data in a wireless network performed by wireless device 100 shown in Fig. 5. The flow illustrated in Fig. 10 is performed when wireless device 100 operates as a slave node.

[0080] 10, the receiving unit 152 receives a scheduling packet transmitted by the master node at the data frequency. The scheduling packet includes a transmission period and a unique ID of a node that is allowed to transmit data.

[0081] In step S32, the transmission control unit 161 determines the transmission timing of the wireless device 100 based on the received scheduling packet. For example, the transmission control unit 161 determines the transmission order of the wireless device 100 from the unique IDs of the nodes that can transmit data, which are included in the received scheduling packet. Specifically, the transmission control unit 161 determines the transmission order of the wireless device 100 based on the largest unique ID of the wireless device 100 among the unique IDs of the nodes that can transmit data. Next, the transmission control unit 161 calculates the transmission timing from the transmission period included in the received scheduling packet and the determined transmission order.

[0082] In step S33, the transmitter 151 broadcasts the data packet at the transmission timing determined by the transmission control unit 161 using the data frequency.

[0083] In step S34, the management unit 165 determines whether or not a cancellation packet has been received by the receiving unit 152. If the receiving unit 152 has not received a cancellation packet (step S34; No), the process ends.

[0084] If the receiving unit 152 receives a release packet (step S34; Yes), the process proceeds to step S35. In step S35, the management unit 165 recognizes the release of the data link and proceeds to calling. For example, the management unit 165 determines whether the unique ID included in the release packet matches the unique ID of the wireless device 100. If the unique ID included in the release packet matches the unique ID of the wireless device 100, the management unit 165 recognizes the release of the data link and proceeds to calling.

[0085] Fig. 11 shows an example of a data transmission sequence according to the embodiment. In the example shown in Fig. 11, wireless device A is the master node, wireless devices B, C, and D are slave nodes, and the same data frequency is assigned to wireless devices B, C, and D. The unique ID of wireless device B is smaller than the unique ID of wireless device C, and the unique ID of wireless device C is smaller than the unique ID of wireless device D.

[0086] Wireless device A transmits a scheduling packet including the unique ID of wireless device A, the transmission period determined by wireless device A, slave information, and data of wireless device A. The master node may transmit the data to be transmitted using the scheduling packet. Wireless devices B, C, and D are identified as nodes capable of transmitting data, and the slave information includes the unique IDs of wireless devices B, C, and D. The time when wireless device A completes transmission of the scheduling packet is defined as T0, the time when a time corresponding to the transmission period has elapsed since time T0 is defined as T1, the time when a time corresponding to the transmission period has elapsed since time T1 is defined as T2, and the time when a time corresponding to the transmission period has elapsed since time T2 is defined as T3.

[0087] Each of wireless devices B, C, and D determines its own transmission timing based on the scheduling packet. Of the unique IDs included in the slave information, wireless device B's unique ID is the smallest, and therefore wireless device B recognizes that it is first in the transmission order. Wireless device B broadcasts data packets during the period from time T0 to time T1. For example, wireless device B starts transmitting data packets after a predetermined time has elapsed from time T0.

[0088] Among the unique IDs included in the slave information, the unique ID of wireless device C is the second smallest, and therefore wireless device C recognizes that it is second in the transmission order. Wireless device C broadcasts data packets during the period from time T1 to time T2. For example, wireless device C starts transmitting data packets after a predetermined time has elapsed from time T1.

[0089] Of the unique IDs included in the slave information, the unique ID of wireless device D is the third smallest, and therefore wireless device D recognizes that it is third in the transmission order. Wireless device C broadcasts data packets during the period from time T2 to time T3. For example, wireless device C starts transmitting data packets after a predetermined time has elapsed from time T2.

[0090] Fig. 12 is a schematic diagram illustrating another example of a data transmission sequence according to the embodiment. The data transmission sequence illustrated in Fig. 12 is executed when wireless device C is abnormal in the data transmission sequence illustrated in Fig. 11.

[0091] Since wireless device A failed to receive a data packet from wireless device C in the previous data transmission sequence, it determines that the data link with wireless device C has been released. Wireless device A broadcasts a scheduling packet including the unique ID of wireless device A, the transmission period determined by wireless device A, slave information, and data of wireless device A. Wireless devices B and D are identified as nodes capable of transmitting data, and the slave information includes the unique IDs of wireless devices B and D. The time when wireless device A completes transmission of the scheduling packet is defined as T4, the time when a time corresponding to the transmission period has elapsed since time T4 is defined as T5, and the time when a time corresponding to the transmission period has elapsed since time T5 is defined as T6.

[0092] Each of wireless devices B and D determines its own transmission timing based on the scheduling packet. Of the unique IDs included in the slave information, wireless device B's unique ID is the smallest, and therefore wireless device B recognizes that it is first in the transmission order. Wireless device B broadcasts data packets during the period from time T4 to time T5. Of the unique IDs included in the slave information, wireless device D's unique ID is the second smallest, and therefore wireless device D recognizes that it is second in the transmission order. Wireless device D broadcasts data packets during the period from time T5 to time T6.

[0093] Each of the wireless devices B, C, and D recognizes from the slave information included in the scheduling packet that the wireless device C has left the wireless network. The wireless device C then returns to call processing.

[0094] As described above, in the wireless system 10, an administrator (master) that manages data transmission is determined for each wireless network 12, and a frequency different from the frequency used for data communication is used for the call process that determines the administrator. This makes routing easier, reduces the load on network management, and suppresses data traffic volume, enabling efficient data transmission. As a result, it becomes possible to establish routing that ensures stable data communication.

[0095] In the above-described embodiment, a unique ID assigned to a wireless device (node) is used as the identifier. In other embodiments, the remaining battery power of the wireless device may be used as the identifier. The master node performs both long-distance and short-distance communication, and therefore consumes a lot of power. When the remaining battery power of the wireless device is used as the identifier, the master will be replaced over time. As a result, power consumption is equalized between wireless devices. In addition, a rule may be used in which a node that is a node in routing according to the shortest path in the network becomes the administrator on a priority basis, or a rule in which a node with a large number of nodes within its communication range becomes the administrator.

[0096] In the above-described embodiment, an example is described in which the communication medium is radio waves. The communication medium is not limited to radio waves, but may be copper wires (e.g., telephone lines), optical fiber cables, coaxial cables, etc. In other words, the routing according to the embodiment is not limited to wireless communication systems, but can also be applied to wired communication systems or communication systems that combine wireless communication systems and wired communication systems. A wireless device is an example of a communication device.

[0097] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0098] 10...wireless system, 12...wireless network, 14...node, 100...wireless device, 101...main body, 102...mobile device, 103...processor, 104...memory, 105...wireless module, 106...observation device, 107...gyro sensor, 108...GPS device, 110...transmitting circuit, 111...slot, 112...synthesis circuit, 151...transmitting unit, 152...receiving unit, 153...communication control unit, 154...memory unit, 155...data processing unit, 161...transmission control unit, 162...classification unit, 163...judgment unit, 164...allocation unit, 165...management unit, 166...scheduling unit.

Claims

1. 1. A communication method performed by a first communication device having a first identifier, the method comprising: receiving a connection request signal at a first frequency transmitted by a second communication device having a second identifier and including the second identifier; determining whether the first communication device is an administrator that manages data transmissions of the second communication device based on a comparison of the first identifier and the second identifier; When it is determined that the first communication device is the administrator, transmitting a connection response signal at the first frequency, the connection response signal including frequency information indicating a second frequency to be used for the data transmission, the second frequency being different from the first frequency; determining a transmission period for switching a communication device that performs data transmission in accordance with the number of communication devices that belong to a wireless network including the second communication device and that are capable of transmitting data when the first communication device is determined to be the administrator; transmitting, at the second frequency, a scheduling signal including the determined transmission period and an identifier of the communication device capable of transmitting data; A communication method comprising:

2. 1. A communication method performed by a first communication device having a first identifier, the method comprising: receiving a connection request signal at a first frequency transmitted by a second communication device having a second identifier and including the second identifier; determining whether the first communication device is an administrator that manages data transmissions of the second communication device based on a comparison of the first identifier and the second identifier; When it is determined that the first communication device is the administrator, transmitting a connection response signal at the first frequency, the connection response signal including frequency information indicating a second frequency to be used for the data transmission, the second frequency being different from the first frequency; Equipped with transmitting the connection response signal calculating a wait time based on a difference between the first identifier and the second identifier; transmitting the connection response signal when the wait time has elapsed since the second communication device completed transmitting the connection request signal; Equipped with Communication method.

3. selecting, from among a plurality of second frequencies different from the first frequency, a second frequency that is least frequently used or that is below a threshold, as the second frequency to be used for the data transmission; The communication method according to claim 1 or 2, further comprising:

4. A communication method performed by a first communication device having a first identifier, comprising: receiving a connection request signal at a first frequency transmitted by a second communication device having a second identifier and including the second identifier; determining whether the first communication device is an administrator that manages data transmissions of the second communication device based on a comparison of the first identifier and the second identifier; When it is determined that the first communication device is the administrator, transmitting a connection response signal at the first frequency, the connection response signal including frequency information indicating a second frequency to be used for the data transmission, the second frequency being different from the first frequency; Equipped with The first identifier uses a remaining battery charge of the first communication device as the first identifier, and a remaining battery charge of the second communication device as the second identifier; each of the first communication device and the second communication device is capable of switching between short-distance communication in which transmission is performed at a first transmission power and long-distance communication in which transmission is performed at a second transmission power higher than the first transmission power, and uses both the short-distance communication and the long-distance communication when the first communication device is the administrator, and uses the short-distance communication when the second communication device is not the administrator; Communication method.

5. 1. A communication method performed by a first communication device having a first identifier, the method comprising: transmitting a connection request signal including the first identifier at a first frequency; receiving, at the first frequency, a connection response signal transmitted by a second communication device having a second identifier different from the first identifier in response to the connection request signal, the connection response signal including frequency information indicating a second frequency different from the first frequency to be used for data transmission; In response to the connection response signal, recognizing that the second communication device is an administrator managing data transmissions of the first communication device; receiving, at the second frequency, a scheduling signal transmitted by the second communication device, the scheduling signal including a transmission period for switching a communication device that performs data transmission and an identifier of a communication device that is capable of transmitting data; determining a transmission timing based on the transmission period and the identifier included in the received scheduling signal and the first identifier; transmitting a data signal at the second frequency at the determined transmission timing; A communication method comprising:

6. Determining the transmission timing includes: determining a transmission order based on the identifier and the first identifier included in the received scheduling signal; calculating the transmission timing from the transmission period included in the received scheduling signal and the determined transmission order; The communication method of claim 5 , comprising:

7. a first communication device having a first identifier; a second communication device having a second identifier; Equipped with the first communication device transmits a connection request signal including the first identifier at a first frequency; the second communication device, receiving the connection request signal transmitted by the first communication device at the first frequency; determining whether the second communication device is an administrator that manages data transmission of the first communication device based on a comparison between the first identifier and the second identifier; transmitting a connection response signal at the first frequency, the connection response signal including frequency information indicating a second frequency to be used for the data transmission, the second frequency being different from the first frequency, when the second communication device is determined to be the administrator; the first communication device, receiving the connection response signal transmitted by the second communication device at the first frequency; Recognizing that the second communication device is the administrator in response to the connection response signal; the second communication device, When it is determined that the second communication device is the administrator, determining a transmission cycle for switching a communication device that performs data transmission according to the number of communication devices that belong to the wireless network including the first communication device and that are capable of transmitting data; transmitting, at the second frequency, a scheduling signal including the determined transmission period and an identifier of the communication device capable of transmitting data; Communication system.

8. a first communication device having a first identifier; a second communication device having a second identifier; Equipped with the first communication device transmits a connection request signal including the first identifier at a first frequency; the second communication device, receiving the connection request signal transmitted by the first communication device at the first frequency; determining whether the second communication device is an administrator that manages data transmission of the first communication device based on a comparison between the first identifier and the second identifier; transmitting a connection response signal at the first frequency, the connection response signal including frequency information indicating a second frequency to be used for the data transmission, the second frequency being different from the first frequency, when the second communication device is determined to be the administrator; the first communication device, receiving the connection response signal transmitted by the second communication device at the first frequency; Recognizing that the second communication device is the administrator in response to the connection response signal; transmitting the connection response signal calculating a wait time based on a difference between the first identifier and the second identifier; transmitting the connection response signal when the wait time has elapsed since the second communication device completed transmitting the connection request signal; Equipped with Communication system.

9. a communication device having a first identifier, a receiving unit configured to receive, at a first frequency, a connection request signal transmitted by another communication device having a second identifier and including the second identifier; a determination unit that determines whether the communication device is an administrator that manages data transmission of the other communication device based on a comparison between the first identifier and the second identifier; a transmitter that, when it is determined that the communication device is the administrator, transmits, at the first frequency, a connection response signal including frequency information indicating a second frequency to be used for the data transmission, which is different from the first frequency; a scheduling unit that, when it is determined that the communication device is the administrator, determines a transmission period for switching a communication device that performs data transmission in accordance with the number of communication devices that belong to a wireless network including the other communication devices and that are capable of transmitting data; Equipped with the transmitting unit transmits, at the second frequency, a scheduling signal including the determined transmission period and an identifier of the communication device capable of transmitting data. Communication equipment.

10. a communication device having a first identifier, a receiving unit configured to receive, at a first frequency, a connection request signal transmitted by another communication device having a second identifier and including the second identifier; a determination unit that determines whether the communication device is an administrator that manages data transmission of the other communication device based on a comparison between the first identifier and the second identifier; a transmission control unit that calculates a wait time based on a difference between the first identifier and the second identifier; a transmitter that, when it is determined that the communication device is the administrator, transmits a connection response signal at the first frequency when the wait time has elapsed since the other communication device completed transmission of the connection request signal, the connection response signal including frequency information indicating a second frequency that is different from the first frequency and that is to be used for the data transmission; A communication device comprising:

11. a communication device having a first identifier, a transmitter that transmits a connection request signal including the first identifier at a first frequency; a receiving unit that receives, at the first frequency, a connection response signal that is transmitted by another communication device having a second identifier different from the first identifier in response to the connection request signal, and that includes frequency information indicating a second frequency that is different from the first frequency and that is used for data transmission; a management unit that, in response to the connection response signal, recognizes that the other communication device is a manager that manages data transmission of the communication device; Equipped with the receiving unit receives, at the second frequency, a scheduling signal transmitted by the other communication device, the scheduling signal including a transmission cycle for switching a communication device that performs data transmission and an identifier of a communication device that can transmit data; the communication device further includes a transmission control unit that determines a transmission timing based on the transmission period and the identifier included in the received scheduling signal and the first identifier; the transmitter transmits a data signal at the second frequency at the determined transmission timing. Communication equipment.

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