Wireless communication device and method

Abstract

To provide a wireless communication device and method capable of achieving power saving.SOLUTION: According to an embodiment, a wireless communication device is provided that forms a network with a plurality of other nodes and operates to receive data in a first slot of a plurality of slots in a first period. The wireless communication device includes first determination means, second determination means, and setting means. The first determination means determines whether data has been received in the first slot. The second determination means, when it is determined that data has not been received in the first slot, determines whether data has been received in a second slot that follows the first slot in the first period. When it is determined that data has been received in the second slot, the setting means sets the second slot as a slot for receiving data in a second period following the first period.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE Embodiments of the present invention relate to wireless communication devices and methods. [Background technology]

[0002] In recent years, it has become known to configure a network (hereinafter referred to as a sensor network) using a plurality of wireless communication devices equipped with sensors and an aggregation device.

[0003] In such a sensor network, for example, data measured by sensors mounted on multiple wireless communication devices (hereinafter referred to as sensor data) is collected by an aggregation device directly from the wireless communication devices or via other wireless communication devices. The sensor data collected by the aggregation device can be used to monitor the state of an object (an object on which the wireless communication devices are installed) where the sensor data was measured, for example.

[0004] However, when multiple wireless communication devices are installed in an environment where it is difficult to supply power, the wireless communication devices need to be operated using power supplied from a battery or the like, and therefore there is a demand for power saving in the wireless communication devices. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2016-54349 A [Patent Document 2] JP 2011-029990 A Summary of the Invention [Problem to be solved by the invention]

[0006] Therefore, an object of the present invention is to provide a wireless communication device and method capable of realizing power saving. [Means for solving the problem]

[0007] According to an embodiment, there is provided a wireless communication device that forms a network with a plurality of other nodes, and that operates to receive data transmitted from the other nodes in a first slot of a plurality of slots in a first period. The wireless communication device includes a first determination means, a second determination means, and a setting means. The first determination means determines whether data has been received in the first slot. When it is determined that data has not been received in the first slot, the second determination means determines whether data transmitted from the other nodes has been received in a second slot that is subsequent to the first slot in the first period. When it is determined that data has been received in the second slot, the setting means sets the second slot as a slot for receiving data transmitted from the other nodes in a second period following the first period. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing an example of a network configuration of a communication system according to a first embodiment. [Diagram 2] 1 is a schematic diagram illustrating a communication system in the form of a network topology. [Diagram 3] FIG. 1 is a diagram for explaining an example of an environment to which a communication system is applied. [Figure 4] FIG. 1 is a diagram for explaining an overview of slot communication performed in a communication system. [Diagram 5] 5A and 5B are diagrams for explaining the communication range of a wireless communication device that changes depending on the position of the wireless communication device; [Figure 6] FIG. 2 is a diagram showing an example of a hardware configuration of a wireless communication device. [Figure 7] FIG. 1 is a block diagram showing an example of a functional configuration of a wireless communication device. [Figure 8] 11 is a flowchart showing an example of a processing procedure of the wireless communication device. [Figure 9] FIG. 1 is a diagram for explaining a specific operation example of a wireless communication device. [Figure 10] FIG. 1 is a diagram for explaining a specific operation example of a wireless communication device. [Figure 11] FIG. 1 is a diagram for explaining a specific operation example of a wireless communication device. [Figure 12] FIG. 11 is a block diagram showing an example of the functional configuration of a wireless communication device according to a second embodiment. [Figure 13] 11 is a flowchart showing an example of a processing procedure of the wireless communication device. [Figure 14] FIG. 11 is a diagram for explaining a third slot change process. [Figure 15] FIG. 1 is a diagram showing an example of the location of a wireless communication device. [Figure 16] FIG. 11 is a diagram showing another example of the positions of wireless communication devices. [Figure 17] FIG. 11 is a block diagram showing an example of the functional configuration of a wireless communication device according to a third embodiment. [Figure 18] 11 is a flowchart showing an example of a processing procedure of the wireless communication device. [Figure 19] FIG. 1 illustrates a wireless communication device in motion. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Each embodiment will be described below with reference to the drawings. (First embodiment) First, a description will be given of a first embodiment. Fig. 1 shows an example of a network configuration of a communication system in this embodiment.

[0010] 1 includes an aggregation device 10 having a function of performing wireless communication (hereinafter, referred to as wireless communication function) and a plurality of wireless communication devices 20. In this embodiment, wireless communication based on, for example, a time division multiplexing system is performed between the aggregation device 10 and the plurality of wireless communication devices 20.

[0011] 1, the aggregation device 10 and the multiple wireless communication devices 20 configure a multi-hop network in which the multiple wireless communication devices 20 are wirelessly connected to the aggregation device 10 in a tree structure. According to the multi-hop network, the multiple wireless communication devices 20 that configure the multi-hop network transfer data in a bucket brigade format, thereby realizing long-distance communication to the aggregation device 10 that exceeds the communication range of each of the multiple wireless communication devices 20.

[0012] The aggregation device 10 and the multiple wireless communication devices 20 that configure the above-mentioned multi-hop network are called nodes in the multi-hop network.

[0013] Fig. 2 is a schematic diagram showing the communication system 1 shown in Fig. 1 in the form of a network topology. The "root" shown in Fig. 2 represents the aggregation device 10 (root node), and "A" to "P" represent each of the multiple wireless communication devices 20.

[0014] 2 indicate data transmission paths. The origin of the arrow indicates the node (child node) that is the data transmission source, and the tip of the arrow indicates the node (parent node) that is the data transmission destination.

[0015] Specifically, for example, the parent node of a wireless communication device 20 represented by "G" (hereinafter referred to as node G) is node E (wireless communication device 20 represented by "E"), which has one fewer hops from the root node than node G. Meanwhile, the child nodes of node G are node I (wireless communication device 20 represented by "I") and node L (wireless communication device 20 represented by "L"), which has one more hop from the root node than node G.

[0016] Although FIG. 2 shows a network topology in which node G is disposed between nodes L and E, the network topology may be such that nodes L and E are directly connected (communicate).

[0017] Furthermore, although it is assumed in FIG. 2 that each wireless communication device 20 transmits (sends) data to the aggregation device 10 (root node), it is also possible for the aggregation device 10 to transmit data to each wireless communication device 20.

[0018] 1 and 2, the communication system 1 is assumed to include, for example, 16 wireless communication devices 20, but in this embodiment, the number of the wireless communication devices 20 may be two or more.

[0019] The network topology and communication method of the communication system 1 in the present embodiment described here are merely examples, and other network topologies and communication methods may be adopted. Specifically, a tree-type network topology is shown in Fig. 2, but the communication system 1 may adopt, for example, a star-type, ring-type, or mesh-type network topology. In addition, the communication system 1 assumes a case in which communication is performed based on, for example, a time division multiplexing method as described above, but communication based on another communication method may be performed.

[0020] Here, in the communication system 1 of this embodiment, the multiple wireless communication devices 20 are equipped with sensors, and the sensors measure sensor data related to an object on which the sensors (wireless communication devices 20) are installed. For example, the sensor data measured by the sensors equipped in the multiple wireless communication devices 20 is collected by the aggregation device 10 directly from the wireless communication devices 20 or via other wireless communication devices 20. The sensor data collected by the aggregation device 10 in this manner is used to monitor the state of the object (for example, a structure or the natural environment) on which the sensor data was measured.

[0021] The sensors mounted on the wireless communication devices 20 include, for example, an acceleration sensor, a temperature sensor, a moisture meter sensor, a water level sensor, and a humidity sensor. When the sensors mounted on the wireless communication devices 20 are acceleration sensors, it is possible to use the sensor data (acceleration data) measured by the acceleration sensor to monitor, for example, the shaking of an elevator, a dam, or the like when an earthquake occurs. When the sensors mounted on the wireless communication devices 20 are temperature sensors, it is possible to use the sensor data (temperature data) measured by the temperature sensor to monitor the abnormal operation of an equipment whose temperature becomes higher than necessary. When the sensors mounted on the wireless communication devices 20 are moisture meter sensors, it is possible to use the sensor data (moisture content data) measured by the moisture meter sensor to monitor the occurrence of a landslide (presence or absence of a landslide) in accordance with the moisture content of the soil in a forest, etc. When the sensors mounted on the wireless communication devices 20 are water level sensors, it is possible to use the sensor data (water level data) measured by the water level sensor to monitor the occurrence of a flood (presence or absence of a flood) in accordance with the water level of a river, etc. In addition, if the sensors installed in the multiple wireless communication devices 20 are humidity sensors, the sensor data (humidity data) measured by the humidity sensor can be used in combination with temperature data, etc., to enable efficient plant cultivation.

[0022] Incidentally, when sensor data is used to monitor the state of a structure or the natural environment as described above, the wireless communication device 20 equipped with a sensor that measures the sensor data may be installed in an environment where it is difficult to supply power from, for example, a commercial power source, etc. In this case, the wireless communication device 20 needs to be driven by power supplied from, for example, a battery, and a mechanism for driving the wireless communication device 20 in a power-saving manner is useful.

[0023] For this reason, the wireless communication device 20 performs communication using slots separated by time division (hereinafter referred to as slot communication), transmitting and receiving data only when necessary, and sleeping at other times, thereby achieving power saving.

[0024] In addition, at least one of the multiple wireless communication devices 20 in this embodiment may be a wireless communication device that operates only as a relay node that relays sensor data measured by a sensor mounted on another wireless communication device 20 from the other wireless communication device 20 to another wireless communication device 20 or the aggregation device 10.

[0025] Hereinafter, with reference to FIG. 3, an example of an environment to which the communication system 1 in this embodiment is applied will be described.

[0026] In Fig. 3, it is assumed that the communication system 1 in this embodiment is applied to an elevator system. As shown in Fig. 3, an elevator 101 (car) connected to one end of a main rope and a counterweight 102 connected to the other end of the main rope are arranged in a hoistway 100, and the elevator 101 can be raised and lowered by driving a hoist (not shown) around which the main rope is wound.

[0027] 3, it is assumed that the aggregation device 10 and two wireless communication devices 20-1 and 20-2 are installed in the above-mentioned elevator shaft 100. Specifically, it is assumed that the aggregation device 10 is installed near an upper floor of a building in which the elevator 101 is installed, the wireless communication device 20-1 is installed near a middle floor of the building, and the wireless communication device 20-2 is installed near a lower floor of the building.

[0028] Further, a wireless communication device 20-3 is installed in the elevator 101 that moves in the hoistway 100 (moves up and down in the hoistway 100). In this case, the wireless communication device 20-3 is assumed to be equipped with an acceleration sensor that measures acceleration data for monitoring the sway of the elevator 101. In Fig. 3, the wireless communication device 20-3 is installed in the elevator 101, but from the viewpoint of monitoring the sway of the elevator 101 as described above, a wireless communication device (acceleration sensor) may be installed in the counterweight 102 that moves up and down in conjunction with the elevator 101.

[0029] 3, the wireless communication devices 20-1 and 20-2 are wireless communication devices that operate only as relay nodes for relaying, for example, sensor data, etc. In this case, the wireless communication devices 20-1 and 20-2 do not need to be equipped with sensors.

[0030] 3, wireless communication devices 20-1 and 20-2 are shown as wireless communication devices 20 operating as relay nodes, but the number of relay nodes may be changed depending on the size of a building in which elevator 101 is installed. Furthermore, in the example shown in FIG 3, for example, wired communication may be performed between aggregation device 10 and wireless communication device 20-1, and wired communication may be performed between wireless communication device 20-1 and wireless communication device 20-2.

[0031] Here, with reference to Fig. 4, an overview of slot communication performed in the communication system 1 applied to the elevator system as shown in Fig. 3 will be described. Note that, here, the wireless communication device 20-3 is driven by power supplied from a cell or battery as described above (i.e., power saving is required), but the aggregation device 10 and the wireless communication devices 20-1 and 20-2 are driven by power supplied from, for example, a commercial power source, and are not subject to power saving in this embodiment.

[0032] 4, in slot communication, a plurality of slots SL1 to SL10 are prepared in a predetermined cycle (hereinafter referred to as a communication cycle) that is repeated, for example, every second, and the aggregation device 10 and the wireless communication devices 20-1 to 20-3 operate to transmit and receive data (perform transmission processing and reception processing) in the predetermined slots. Note that a plurality of time periods into which the communication cycle is divided are assigned to the plurality of slots SL1 to SL10.

[0033] Specifically, the aggregation device 10 operates to transmit data in (the time period assigned to) slot SL6 in the communication cycle, and to receive data in (the time periods assigned to) other slots SL1 to SL5 and SL7 to SL10. In the following description, a slot in which the aggregation device 10 transmits data (a slot in which a time period in which the data can be transmitted is assigned) is referred to as the transmission slot of the aggregation device 10, and a slot in which the aggregation device 10 receives data (a slot in which a time period in which the data can be received is assigned) is referred to as the reception slot of the aggregation device 10.

[0034] Moreover, the wireless communication device 20-1 operates to transmit data in slot SL7 in a communication cycle, and to receive data in the other slots SL1 to SL6 and SL8 to SL10. In the following description, the slots through which the wireless communication device 20-1 transmits data are referred to as the transmission slots of the wireless communication device 20-1, and the slots through which the wireless communication device 20-1 receives data are referred to as the reception slots of the wireless communication device 20-1.

[0035] Furthermore, the wireless communication device 20-2 operates to transmit data in slot SL8 in the communication cycle, and to receive data in the other slots SL1 to SL7, SL9, and SL10. In the following description, the slots through which the wireless communication device 20-2 transmits data are referred to as the transmission slots of the wireless communication device 20-2, and the slots through which the wireless communication device 20-2 receives data are referred to as the reception slots of the wireless communication device 20-2.

[0036] On the other hand, the wireless communication device 20-3 operates to transmit data in slot SL2 in the communication cycle, receive data in slot SL6, and sleep in the other slots SL1, SL3 to SL5, and SL7 to SL10. In the following description, the slots through which the wireless communication device 20-3 transmits data are referred to as the transmission slots of the wireless communication device 20-3, and the slots through which the wireless communication device 20-3 receives data are referred to as the reception slots of the wireless communication device 20-3. In this case, there may be multiple wireless communication devices that operate in a power-saving manner similar to the wireless communication device 20-3. Also, any slot between SL1 to SL5 may be used as the transmission slot. However, a slot specific to each wireless communication device is used as the transmission slot.

[0037] According to the operation of the wireless communication device 20-3 described above, the wireless communication device 20-3 executes reception processing only at limited times (i.e., minimizes the reception range) compared to the aggregation device 10 and the wireless communication devices 20-1 and 20-2, thereby enabling power saving.

[0038] 4, the transmission slot of the wireless communication device 20-3 is slot SL2, so the wireless communication device 20-3 transmits data in the slot SL2. The data transmitted from the wireless communication device 20-3 in slot SL2 is, for example, sensor data measured by a sensor mounted on the wireless communication device 20-3 (for example, acceleration data measured by an acceleration sensor), etc.

[0039] For example, when the aggregation device 10, for which slot SL2 is a receiving slot, is within the communication range of the wireless communication device 20-3, as described above, the data transmitted from the wireless communication device 20-3 in slot SL2 is received by the aggregation device 10. Since slot SL2 is also a receiving slot for the wireless communication devices 20-1 and 20-2, when the wireless communication devices 20-1 and 20-2 are within the communication range of the wireless communication device 20-3, the wireless communication devices 20-1 and 20-2 can also receive the data transmitted from the wireless communication device 20-3 in the same manner.

[0040] As described above, when the aggregation device 10 receives data transmitted from the wireless communication device 20-3 in slot SL2, the aggregation device 10 transmits data corresponding to the received data in slot SL6, which is the transmission slot of the aggregation device 10. The data transmitted from the aggregation device 10 in slot SL6 is, for example, data including acknowledgement information for the sensor data transmitted from the wireless communication device 20-3. Since the reception slot of the wireless communication device 20-3 is slot SL6, when the aggregation device 10 is within the communication range of the wireless communication device 20-3, the wireless communication device 20-3 can receive the data transmitted from the aggregation device 10 in slot SL6 and can continue to operate appropriately.

[0041] It is assumed that the transmission slots and reception slots (i.e., the timing at which the transmission process is executed and the timing at which the reception process is executed) of each of the aggregation device 10 and the wireless communication devices 20-1 to 20-3 described above are preset based on, for example, the arrangement of the aggregation device 10 and the wireless communication devices 20-1 to 20-3.

[0042] Also, the communication cycle may be composed of a plurality of subcycles. In this case, for example, if the time period allocated to the slots SL1 to SL5 corresponds to the first subcycle and the time period allocated to the slots SL6 to SL10 corresponds to the second subcycle, it becomes possible to determine the transmission slot of the wireless communication device 20-3 from the slots SL1 to SL5, and to determine the transmission slots of the aggregation device 10 and the relay nodes (wireless communication devices 20-1 and 20-2) from the slots SL6 to SL10 (that is, to manage the transmission slots for each subcycle).

[0043] Incidentally, assuming that the wireless communication device 20-3 is installed in the elevator 101 as shown in Fig. 3 above, the position of the wireless communication device 20-3 (i.e., the distance from, for example, the aggregation device 10, etc.) changes as the elevator 101 ascends and descends (moves up and down) in the hoistway 100 as shown in Fig. 5. Hereinafter, for example, when the wireless communication device 20-3 is in the position shown in Fig. 5, it is assumed that the aggregation device 10 and the wireless communication device 20-1 are not within the communication range of the wireless communication device 20-3, and the wireless communication device 20-2 is within the communication range of the wireless communication device 20-3.

[0044] As described above, when the elevator 101 moves and the aggregation device 10 is outside the communication range of the wireless communication device 20-3, the data transmitted by the wireless communication device 20-3 in the slot SL2 is not directly received by the aggregation device 10, but is received by the wireless communication device 20-2 in the communication range of the wireless communication device 20-3, for example, in the slot SL2, which is the reception slot, and is transmitted from the wireless communication device 20-2 in the slot SL8, which is the transmission slot of the wireless communication device 20-2. The data transmitted from the wireless communication device 20-2 in this way is received by the wireless communication device 20-1 in the communication range of the wireless communication device 20-2, for example, in the slot SL8, which is the reception slot, and is transmitted from the wireless communication device 20-1 in the slot SL7 of the next communication period, which is the transmission slot of the wireless communication device 20-1. The data transmitted from the wireless communication device 20-1 in this way is received by the aggregation device 10 in which the slot SL7 is the reception slot.

[0045] In this way, even if the elevator 101 moves so that the aggregation device 10 is outside the communication range of the wireless communication device 20-3, the data transmitted from the wireless communication device 20-3 is relayed by the wireless communication devices 20-1 and 20-2 and collected by the aggregation device 10.

[0046] On the other hand, when the aggregation device 10 receives data from the wireless communication device 20-3 as described above, the aggregation device 10 transmits data corresponding to the received data in slot SL6, which is the transmission slot of the aggregation device 10. However, when the elevator 101 moves as described above and the aggregation device 10 is out of the communication range of the wireless communication device 20-3, for example, the wireless communication device 20-3 cannot receive the data transmitted from the aggregation device 10 in slot SL6.

[0047] In addition, the data transmitted from the aggregation device 10 is relayed by the wireless communication devices 20-1 and 20-2. However, even if the data is transmitted from the wireless communication device 20-2 in slot SL8, which is the transmission slot of the wireless communication device 20-2, the data cannot be received by the wireless communication device 20-3 because the slot SL8 is not the reception slot of the wireless communication device 20-3.

[0048] In this way, if the data (eg, delivery confirmation information, etc.) transmitted from the aggregation device 10 is not received by the wireless communication device 20-3, the wireless communication device 20-3 may not be able to continue to operate appropriately.

[0049] As described above, when the wireless communication device 20-3 does not receive data transmitted from the aggregation device 10, the wireless communication device 20-3 must search for another node (here, the wireless communication device 20-2) within the communication range of the wireless communication device 20-3 and change (the setting of) the reception slot of the wireless communication device 20-3 in order to receive the data from the aggregation device 10. However, if a search is performed to execute reception processing in all slots (i.e., the search takes a long time), this hinders power saving in the wireless communication device 20-3.

[0050] In addition, it is possible to receive data in a number of predetermined slots (transmission slots of multiple candidate data transmission sources) so as to eliminate the need for searching, but if reception processing is always performed in multiple slots, it becomes difficult to achieve power saving in the wireless communication device 20-3.

[0051] Therefore, in this embodiment, a configuration is described in which, when a wireless communication device 20 installed in a moving body (e.g., an elevator 101) does not receive data transmitted from other nodes, the receiving slot setting is efficiently changed (i.e., the receiving timing is changed) to achieve power saving.

[0052] Note that the wireless communication device 20 described below is intended to be, for example, the wireless communication device 20-3 described in FIG. 3 and the like, but may be one of the multiple wireless communication devices 20 shown in FIG.

[0053] Fig. 6 shows an example of a hardware configuration of the wireless communication device 20. As shown in Fig. 6, the wireless communication device 20 includes a microcomputer 20a, a wireless communication module 20b, a sensor 20c, and the like.

[0054] The microcomputer 20a is composed of a processor (CPU) and a memory that controls the operation of each component in the wireless communication device 20. The wireless communication module 20b is configured to transmit and receive data, and includes, for example, an antenna. The sensor 20c is configured to measure sensor data as described above.

[0055] 7 is a block diagram showing an example of a functional configuration of the wireless communication device 20. As shown in FIG. 7, the wireless communication device 20 includes a transmission / reception processing unit 21, a determination unit 22, and a slot setting unit .

[0056] In this embodiment, some or all of the units 21 to 23 shown in FIG. 7 may be realized by causing the microcontroller 20a (processor) shown in FIG. 6 to execute a predetermined program (i.e., software), or may be realized by hardware such as an IC (Integrated Circuit), or may be realized by a configuration that combines software and hardware.

[0057] The transmission and reception processing unit 21 executes a process of transmitting data in a transmission slot (data transmission process) based on, for example, a preset transmission slot of the wireless communication device 20. Note that, when the data transmitted in the transmission process executed by the transmission and reception processing unit 21 is the above-mentioned sensor data, the sensor data may be acquired from the sensor 20c shown in Fig. 6. Note that the data transmitted in the transmission process executed by the transmission and reception processing unit 21 may be data other than the sensor data.

[0058] Furthermore, the transmission / reception processing unit 21 executes a process of receiving data in a reception slot (data reception process) based on a preset reception slot of the wireless communication device 20. Note that the data received in the reception process executed by the transmission / reception processing unit 21 is assumed to be data including the above-mentioned delivery confirmation information, but may be, for example, control data (data for controlling the wireless communication device 20) transmitted from the aggregation device 10.

[0059] The determination unit 22 determines whether or not data has been received in the reception slot of the wireless communication device 20.

[0060] If the determining unit 22 determines that no data is being received, the slot setting unit 23 changes the setting of the receiving slot of the wireless communication device 20 (that is, controls the receiving slot).

[0061] Hereinafter, an example of a processing procedure of the wireless communication device 20 will be described with reference to the flowchart of Fig. 8. In the following description, the wireless communication device 20 that executes the processing shown in Fig. 8 will be referred to as the target wireless communication device 20. In addition, "other nodes" in the following description include wireless communication devices 20 other than the aggregation device 10 and the target wireless communication device 20.

[0062] First, the transmission / reception processing unit 21 included in the target wireless communication device 20 transmits data (e.g., sensor data) destined for the aggregation device 10 in a transmission slot of the target wireless communication device 20 in a predetermined communication period, for example. The data transmitted in step S1 is assumed to be added with identification information indicating the target wireless communication device 20 as source information indicating the source, and identification information for identifying the aggregation device 10 as destination information indicating the destination.

[0063] When the aggregating device 10 is within the communication range of the target wireless communication device 20, the data transmitted in step S1 is directly received by the aggregating device 10. On the other hand, when the aggregating device 10 is not within the communication range of the target wireless communication device 20, the data transmitted in step S1 is received by the aggregating device 10 via another wireless communication device 20 other than the target wireless communication device 20.

[0064] When data from the target wireless communication device 20 is received at the aggregation device 10, the aggregation device 10 transmits data corresponding to the data (e.g., data including delivery confirmation information for the sensor data) in the transmission slot of the aggregation device 10. The data transmitted from the aggregation device 10 is assumed to be added with identification information for identifying the aggregation device 10 as source information indicating the source, and identification information for identifying the target wireless communication device 20 as destination information indicating the destination. The data transmitted from the aggregation device 10 may further be added with slot information indicating the transmission slot in which the data is transmitted, etc.

[0065] Here, the transmission / reception processing unit 21 included in the target wireless communication device 20 executes reception processing in the reception slot of the target wireless communication device 20 (step S2). In this case, for example, if the reception slot of the target wireless communication device 20 is the same as the transmission slot of the aggregation device 10 and the aggregation device 10 is within the communication range of the target wireless communication device 20, the processing of step S2 is executed, so that the data transmitted from the aggregation device 10 can be received. On the other hand, even if the reception slot of the target wireless communication device 20 is the same as the transmission slot of the aggregation device 10, if the aggregation device 10 is not within the communication range of the target wireless communication device 20, the data transmitted from the aggregation device 10 cannot be received even if the processing of step S2 is executed. Here, the data transmitted from the aggregation device 10 has been described, but the same applies to data transmitted from another wireless communication device 20 that relays data from the aggregation device 10.

[0066] When the process of step S2 is executed, the determination unit 22 determines whether or not data has been received (step S3).

[0067] If it is determined that no data has been received (NO in step S3), the transmission and reception processing unit 21 extends the range of the reception slots of the target wireless communication device 20 and continues to execute the reception process (step S4).

[0068] In this case, the target wireless communication device 20 (the transmission / reception processing unit 21) operates to perform reception processing also in slots following the reception slot of the target wireless communication device 20 in the communication cycle in which the reception processing was performed in step S2 (hereinafter referred to as the target communication cycle).

[0069] For example, the slot setting unit 23 included in the target wireless communication device 20 manages (slot information indicating) transmission slots of other nodes (aggregation device 10 and other wireless communication devices 20). In this case, the slot in which the reception process is continuously executed in step S4 (the slot following the reception slot of the target wireless communication device 20) may be the slot immediately following the reception slot in the target communication cycle, or may be the slot closest to the reception slot among the transmission slots of the other nodes.

[0070] Next, the determination unit 22 determines whether or not data has been received in the reception process executed in step S4 (step S5).

[0071] If it is determined that data has been received (YES in step S5), the slot setting unit 23 executes a first slot change process (step S6).

[0072] Here, when it is determined in step S5 that data has been received, this means that another node, for which the slot in which the receiving process was performed in step S4 (i.e., the slot in which the data was received) is a transmission slot, is within the communication range of the target wireless communication device 20.

[0073] Therefore, in the first slot change process, the slot in which the reception process was executed in step S4 is newly set as the reception slot of the target wireless communication device 20 (i.e., the reception slot of the target wireless communication device 20 is changed to the slot in which data was received).

[0074] On the other hand, if it is determined that no data has been received (NO in step S5), the slot setting unit 23 determines whether the slot in which the receiving process was executed in step S4 is the last slot in the target communication cycle (step S7). Note that the last slot in the target communication cycle may be the slot located at the end of the multiple slots in the target communication cycle (the slot to which the last time slot constituting the target communication cycle is assigned), or may be the last slot of the transmission slots of other nodes.

[0075] If it is determined that the slot in which the reception process was performed is not the last slot (NO in step S7), the process returns to step S4 and is repeated. In this case, the reception process is continued in the slot following the slot in which the reception process was last performed.

[0076] On the other hand, if it is determined that the slot in which the reception process has been executed is the last slot (YES in step S7), the slot setting unit 23 executes a second slot change process (step S8).

[0077] Here, if it is determined in step S7 that the slot in which the receiving process was performed is the last slot (i.e., data is not received until the last slot), there is a high possibility that another node whose transmitting slot is a slot preceding the receiving slot of the target wireless communication device 20 is within the communication range of the target wireless communication device 20.

[0078] Therefore, in the second slot change process, the slot M before the receiving slot of the target wireless communication device 20 is newly set as the receiving slot of the target wireless communication device 20 (i.e., the receiving slot of the target wireless communication device 20 is changed to the slot M before the receiving slot).

[0079] In addition, the slot M before the receiving slot of the target wireless communication device 20 may be the slot M before the receiving slot among multiple slots in the communication period, or it may be the slot M before the receiving slot among the transmitting slots of another node.

[0080] When the processing of step S6 (first slot change processing) or the processing of step S8 (second slot change processing) described above is executed, slot information indicating the newly set receiving slot is output from the slot setting unit 23 to the transmission / reception processing unit 21, and the transmission / reception processing unit 21 executes receiving processing in the communication cycle next to the target communication cycle based on the slot information (the receiving slot indicated by the slot information).

[0081] In the above steps S3 and S5, when data to which identification information for identifying the target wireless communication device 20 is added as destination information is received, it is determined that the data has been received. In other words, even when data has been received, if identification information for identifying the target wireless communication device 20 is not added to the data (i.e., the data is not data destined for the target wireless communication device 20), it is determined in steps S3 and S5 that the data has not been received. When data to which identification information for identifying the target wireless communication device 20 is not added (i.e., data to which identification information for identifying another wireless communication device 20 is added) is received, the transmission / reception processing unit 21 transmits (transfers) the data in the transmission slot of the target wireless communication device 20.

[0082] In addition, assuming that data including delivery confirmation information for sensor data from the target wireless communication device 20 is expected to be received in the receiving slot of the target wireless communication device 20, if data not including the delivery confirmation information is received, it may be determined in steps S3 and S5 that the data has not been received.

[0083] If it is determined in step S3 that data has been received (YES in step S3), it is presumed that another node, whose reception slot is a transmission slot of the target wireless communication device 20, is within the communication range of the target wireless communication device 20 (that is, the reception slot is set to receive data transmitted from another node within the communication range of the target wireless communication device 20). In this case, the process shown in FIG. 8 is terminated without changing (the setting of) the reception slot of the target wireless communication device 20.

[0084] Hereinafter, a specific example of the operation of the wireless communication device 20 according to the present embodiment will be described with reference to FIGS.

[0085] First, assume that the aggregation device 10 and wireless communication devices 20-1 to 20-3 shown in Fig. 3 are performing transmission and reception processing based on the transmission slots and reception slots shown on the left side of Fig. 9. Note that the left side of Fig. 9 is the same as Fig. 4 except that the communication cycle shown in Fig. 4 is written as the first communication cycle, so detailed description thereof will be omitted here.

[0086] Here, for example, it is assumed that data (e.g., sensor data) is transmitted from the wireless communication device 20-3 (target wireless communication device) in slot SL2 in the first communication cycle, and data corresponding to the data (data including delivery confirmation information) is transmitted from the aggregation device 10 in slot SL6.

[0087] In this case, when the aggregation device 10 is within the communication range of the wireless communication device 20-3 (i.e., when the elevator 101 is near an upper floor), the wireless communication device 20-3 can receive data transmitted from the aggregation device 10 in slot SL6, which is the receiving slot of the wireless communication device 20-3.

[0088] On the other hand, if the aggregation device 10 is not within the communication range of the wireless communication device 20-3 due to the movement of the elevator 101 in which the wireless communication device 20-3 is installed, the wireless communication device 20-3 cannot receive the data transmitted from the aggregation device 10 in slot SL6. When the wireless communication device 20-3 does not receive data in this way, as shown in the center of Fig. 9, the wireless communication device 20-3 extends the reception slot to slot SL7 and continues the reception process.

[0089] As described above, the wireless communication device 20-3 cannot receive data transmitted from the aggregation device 10 in slot SL6, but the wireless communication device 20-1 operates to receive data transmitted from the aggregation device 10 in slot SL6 and transmit (transfer) the data in slot SL7.

[0090] According to this, when the wireless communication device 20-1 is within the communication range of the wireless communication device 20-3 (i.e., the elevator 101 is near a middle floor), the wireless communication device 20-3 can receive data transmitted from the wireless communication device 20-1 in the slot SL7. When the wireless communication device 20-3 receives data in the slot SL7 in this way, the slot SL7 is newly set as a receiving slot for the wireless communication device 20-3.

[0091] In this case, as shown on the right side of Figure 9, in the second communication cycle following the first communication cycle, the wireless communication device 20-3 operates to perform reception processing in slot SL7, and is therefore able to receive data transmitted from the wireless communication device 20-1.

[0092] In addition, in Fig. 9, the case where the elevator 101 is near a middle floor has been described, but if the elevator 101 is near a lower floor and the wireless communication device 20-1 is not within the communication range of the wireless communication device 20-3, the wireless communication device 20-3 cannot receive the data transmitted from the wireless communication device 20-1 in slot SL7. In this way, when the wireless communication device 20-3 does not receive data, as shown in the left side of the lower part of Fig. 10, the wireless communication device 20-3 extends the reception slot to slot SL8 and continues the reception process. Note that the left and right sides of the upper part of Fig. 10 are the same as the left and center of Fig. 9, and show that the reception slot of the wireless communication device 20-3 is extended to slot SL7.

[0093] As described above, wireless communication device 20-3 cannot receive data transmitted from wireless communication device 20-1 in slot SL7, but wireless communication device 20-2 operates to receive data transmitted from wireless communication device 20-1 in slot SL7 and transmit (transfer) the data in slot SL8.

[0094] According to this, when the wireless communication device 20-2 is within the communication range of the wireless communication device 20-3 (i.e., the elevator 101 is near a low floor), the wireless communication device 20-3 can receive data transmitted from the wireless communication device 20-2 in the slot SL8. When the wireless communication device 20-3 receives data in the slot SL8 in this way, the slot SL8 is newly set as a receiving slot for the wireless communication device 20-3.

[0095] In this case, as shown in the lower right side of Figure 10, in the second communication cycle following the first communication cycle, the wireless communication device 20-3 operates to perform receiving processing in slot SL8, and is therefore able to receive data transmitted from the wireless communication device 20-2.

[0096] 11, after slot SL8 is set as the receiving slot of wireless communication device 20-3, data is transmitted from wireless communication device 20-3 in slot SL2 in the second communication cycle, and data corresponding to the data is transmitted from aggregation device 10 in slot SL6. The data transmitted from aggregation device 10 in slot SL6 is received by wireless communication device 20-1, and transmitted (transferred) from wireless communication device 20-1 in slot SL7. Moreover, the data transmitted from wireless communication device 20-1 in slot SL7 is received by wireless communication device 20-2, and transmitted (transferred) from wireless communication device 20-2 in slot SL8.

[0097] In the example shown on the left side of Figure 11, wireless communication device 20-3 performs receiving processing in slot SL8, but if wireless communication device 20-2 is not within the communication range of wireless communication device 20-3, for example because wireless communication device 20-3 moves, wireless communication device 20-3 cannot receive the data transmitted from wireless communication device 20-2 in slot SL8.

[0098] If the above-mentioned slot SL8 is the last slot among the transmission slots of the other nodes in the second communication cycle, the slot M before the slot SL8 (the reception slot of the wireless communication device 20-3) is newly set as the reception slot of the wireless communication device 20-3. Specifically, for example, the slot SL7 one before the slot SL8 can be set as the reception slot of the wireless communication device 20-3.

[0099] In this case, as shown on the right side of Figure 11, in the third communication cycle following the second communication cycle, the wireless communication device 20-3 operates to perform reception processing in slot SL7, and is therefore able to receive data transmitted from the wireless communication device 20-1.

[0100] In FIG. 11, it has been described that the slot SL7 immediately preceding slot SL8, which is the receiving slot of wireless communication device 20-3, is set as the receiving slot of wireless communication device 20-3. However, for example, the slot SL6 two slots preceding slot SL8 (the transmission slot of aggregation device 10, which is the first slot among the transmission slots of other nodes) may be set as the receiving slot of wireless communication device 20-3, or another slot preceding slot SL8 may be set as the receiving slot of wireless communication device 20-3.

[0101] As described above, in this embodiment, if it is determined that no data has been received in the first slot in the first communication cycle, it is determined whether data (second data) transmitted from another node has been received in the second slot following the first slot, and if it is determined that data has been received in the second slot, the second slot is set as the reception slot of the wireless communication device 20 in the second communication cycle following the first communication cycle (a slot for receiving data transmitted from another node).

[0102] In this embodiment, it is assumed that the wireless communication device 20 is installed in a moving object (e.g., elevator 101) that moves so that the distance to other nodes changes. It is also assumed that the wireless communication device 20 is installed in an environment where it is difficult to supply power from a commercial power source, for example, and is driven by power supplied from a cell or battery.

[0103] In this embodiment, with the above-mentioned configuration, even in an environment in which other nodes with which the wireless communication device 20 can communicate (i.e., other nodes within the communication range of the wireless communication device 20) change frequently as the wireless communication device 20 moves, it is possible to improve the power saving of the wireless communication device 20 by appropriately changing the reception slot of the wireless communication device 20. In other words, according to this embodiment, even if the wireless communication device 20 moves, it is possible to change the reception slot so that data transmitted in the transmission slot of another node with which the wireless communication device 20 can communicate is received, thereby minimizing the reception range and realizing power saving.

[0104] Furthermore, in this embodiment, if it is determined that no data is received in the second slot (the last slot of multiple slots in a communication cycle), a third slot before the first slot (the slot M slots before the reception slot of the wireless communication device 20) is newly set as the reception slot of the wireless communication device 20. In this embodiment, with such a configuration, if data is not received in the last slot, a slot in which data can be received in the next communication cycle can be re-set as the reception slot of the wireless communication device 20, thereby improving the efficiency of reception processing in the wireless communication device 20.

[0105] With regard to the above-mentioned M slots before, for example, when it is expected that the wireless communication device 20 will move a small amount, it may be possible to search for other nodes with which communication can be performed with fewer reception processes by setting the slot one slot before the reception slot of the wireless communication device 20 as the reception slot. On the other hand, for example, when the first slot of multiple slots is set as the reception slot of the wireless communication device 20, it is considered that it is possible to more reliably search for other nodes with which communication can be performed in the next communication cycle and to re-set the transmission slot of the other node as the reception slot of the wireless communication device 20. That is, M (number) of "M slots before" in this embodiment may be determined based on the type or characteristics of a moving body (for example, an object for measuring sensor data) on which the wireless communication device 20 is installed.

[0106] In addition, in this embodiment, it has been described that data including delivery confirmation information for the sensor data transmitted from the wireless communication device 20 is transmitted from the aggregation device 10 and the wireless communication device 20 receives the data, but the data may be other data (for example, control data that the aggregation device 10 issues instructions to the wireless communication device 20, etc.).

[0107] Furthermore, in this embodiment, it is determined whether data has been received, but the determination process may be performed based on whether the data includes delivery confirmation information. Specifically, for example, even if data has been received, if the data does not include delivery confirmation information, it may be determined that the data has not been received.

[0108] The determination process may be performed based on the received signal strength of the data. Specifically, for example, even if data is received, if the received signal strength of the data is less than a predetermined value, it may be determined that the data is not received.

[0109] In addition, the data is accompanied by, for example, destination information (identification information of the destination) indicating the destination of the data and slot information (slot information) indicating the transmission slot in which the data was transmitted, and the above-mentioned determination process may be performed using the destination information and slot information, etc.

[0110] Furthermore, the determination process may be performed based on the number of times data is received in a reception slot in each of a plurality of communication cycles (first cycles), for example. Specifically, it may be determined that data has been received when data has been received in a reception slot over a plurality of communication cycles (i.e., data has been successfully received a plurality of times), and it may be determined that data has not been received when the number of times the data has been successfully received is less than a predetermined number.

[0111] In this embodiment, the elevator 101 has been mainly described as an example of a moving body in which the wireless communication device 20 is installed, but the wireless communication device 20 may be installed in other moving bodies such as a train.

[0112] Second embodiment Next, a second embodiment will be described. Note that in this embodiment, detailed descriptions of the same parts as those in the first embodiment will be omitted.

[0113] This embodiment differs from the first embodiment described above in that the position of the wireless communication device (or the mobile object on which the wireless communication device is installed) is used when changing the settings of the reception slot of the wireless communication device.

[0114] The configuration of the wireless communication device according to this embodiment will be described below, but since the hardware configuration of the wireless communication device 20 is similar to that of the first embodiment described above, a detailed description thereof will be omitted here.

[0115] Fig. 12 is a block diagram showing an example of the functional configuration of a wireless communication device according to this embodiment. In Fig. 12, the same reference numerals are given to the same components as those in Fig. 7 described above, and detailed description thereof will be omitted.

[0116] 12, the wireless communication device 20 includes a location information acquisition unit 24. Note that the location information acquisition unit 24 may be realized by software, may be realized by hardware, or may be realized by a configuration in which software and hardware are combined.

[0117] The location information acquisition unit 24 acquires location information indicating the location of the wireless communication device 20. The location information can be acquired, for example, by using a GPS (Global Positioning System) function of the wireless communication device 20 (or a mobile object on which the wireless communication device is installed) or, in the case of an elevator, by using the position of the elevator car.

[0118] The location information acquired by the location information acquisition unit 24 is output to the slot setting unit 23 and is used when the slot setting unit 23 changes the setting of the reception slot of the wireless communication device 20 .

[0119] Hereinafter, an example of a processing procedure of the wireless communication device 20 will be described with reference to the flowchart of Fig. 13. In the following description, the wireless communication device 20 that executes the processing shown in Fig. 13 will be referred to as a target wireless communication device 20.

[0120] First, the processes of steps S11 to S17 corresponding to the processes of steps S1 to S7 shown in FIG. 8 described above are executed.

[0121] If it is determined that the slot in which the reception process has been executed is the last slot (YES in step S17), the slot setting unit 23 executes a third slot change process (step S18).

[0122] Here, in the first embodiment described above, it was explained that a second slot change process is executed in which a slot M slots before the receiving slot of the target wireless communication device 20 is newly set as the receiving slot of the target wireless communication device 20 (i.e., the receiving slot of the target wireless communication device 20 is changed to the slot M slots before the receiving slot), but in the third slot change process in this embodiment, a new receiving slot of the target wireless communication device 20 is set using location information indicating the location of the target wireless communication device 20 described above.

[0123] The third slot change process will be described below. First, assume that the aggregation device 10 and the wireless communication devices 20-1 to 20-3 shown in Fig. 3 operate as shown in the left side of Fig. 14. Specifically, assume that the third slot change process is executed because no data is received in slot SL8 (the last slot), which is the reception slot of the wireless communication device 20-3 in the second communication cycle described in the first embodiment.

[0124] In this case, the position information acquisition unit 24 included in the wireless communication device 20-3 acquires position information (hereinafter, referred to as first position information) indicating the position of the wireless communication device 20-3. Here, as shown in Fig. 15, the position of the wireless communication device 20-3 indicated by the first position information is assumed to be a position near an upper floor of the building in which the elevator 101 is installed.

[0125] Here, it is assumed that the wireless communication device 20-3 internally holds in advance position information (hereinafter, referred to as second position information) indicating the positions of the other nodes (the aggregation device 10, the wireless communication devices 20-1 and 20-2).

[0126] In this case, the slot setting unit 23 identifies the aggregation device 10 as another node close to the location of the wireless communication device 20-3 based on the first and second location information. The slot setting unit 23 newly sets the slot SL6, which is the transmission slot of the aggregation device 10 thus identified, as the reception slot of the wireless communication device 20-3.

[0127] In this case, as shown on the right side of Figure 14, in the third communication cycle following the second communication cycle, the wireless communication device 20-3 operates to perform receiving processing in slot SL6, and is therefore able to receive data transmitted from the aggregation device 10.

[0128] Here, the position of the wireless communication device 20-3 indicated by the first position information has been described as being in the vicinity of an upper floor of a building, but when the position of the wireless communication device 20-3 is in the vicinity of a middle floor of the building as shown in Fig. 16, the wireless communication device 20-1 is specified as another node close to the position. In this case, the slot setting unit 23 newly sets the slot SL7, which is the transmission slot of the wireless communication device 20-1 thus specified, as the reception slot of the wireless communication device 20-3, thereby making it possible to receive data transmitted from the wireless communication device 20-1 in the third communication cycle.

[0129] As described above, in this embodiment, if it is determined that no data is received, for example, in the last slot (second slot) in a communication cycle, the position of the wireless communication device 20 is acquired, and the transmission slot of another node close to the acquired position (i.e., the third slot in which the other node transmits data) is set as the reception slot of the wireless communication device 20.

[0130] In this embodiment, compared to the configuration described in the first embodiment in which the reception slot is set to a slot M slots before the reception slot of the wireless communication device 20, the reception slot is set to a slot for receiving data from other nodes (i.e., other nodes assumed to have good communication quality) close to the position of the wireless communication device 20 in the next communication cycle. Therefore, it is considered that it is possible to reduce the time period during which reception processing is unnecessarily performed (i.e., to avoid increasing power consumption) even if the wireless communication device 20 (or the mobile body on which it is installed) moves.

[0131] In this embodiment, the third slot change process is executed when it is determined that the slot in which the reception process was executed in step S17 shown in Fig. 13 is the last slot (i.e., data is not received in the last slot), but the third slot change process may be executed when it is determined that data is not received in step S13. To explain this in detail using Fig. 3 and Fig. 4, for example, when the reception slot of wireless communication device 20-3 is slot SL6 and data is not received in slot SL6, and another node close to the position of wireless communication device 20-3 is wireless communication device 20-2, wireless communication device 20-3 may execute reception process in slot SL8 which is the transmission slot of wireless communication device 20-2.

[0132] In addition, in the configuration in which the third slot change process is executed when it is determined in step S13 that no data has been received, if data is not received in the newly set reception slot as a result of the execution of the third slot change process and there is a slot (a transmission slot of another node) after the reception slot, the process from step S14 onwards may be executed.

[0133] Furthermore, in this embodiment, for example, a GPS function is used to obtain location information indicating the location of the wireless communication device 20. However, the location information may be any information that can identify other nodes close to the wireless communication device 20.

[0134] Therefore, for example, when wireless communication device 20 is installed in elevator 101, information indicating the position (stop floor) of elevator 101 obtained from an elevator control device that controls elevator 101 may be obtained as position information. Also, position information may be obtained using, for example, an RFID tag attached in hoistway 100. Furthermore, position information may be obtained based on control information (information indicating the stop floor, etc.) that controls elevator 101 output from the elevator control device.

[0135] Furthermore, for example, when the wireless communication device 20 is installed on a train, the location information (location information indicating the location of the train) may be acquired from, for example, a traffic management system that manages the operation of the train.

[0136] In addition, in this embodiment, it has been described that location information indicating the locations of other nodes (aggregation device 10, wireless communication devices 20-1 and 20-2) is stored in advance inside wireless communication device 20-3, but the location information may be configured to be acquired (received) from an external device when the third slot change process is executed.

[0137] Third embodiment Next, a third embodiment will be described. Note that in this embodiment, detailed descriptions of the same parts as those in the first and second embodiments will be omitted.

[0138] This embodiment differs from the first and second embodiments described above in that, when changing the settings of the reception slots of a wireless communication device, consideration is given to whether the wireless communication device (or the mobile object in which it is installed) is moving.

[0139] The configuration of the wireless communication device according to this embodiment will be described below, but since the hardware configuration of the wireless communication device 20 is similar to that of the first and second embodiments described above, a detailed description thereof will be omitted here.

[0140] Fig. 17 is a block diagram showing an example of the functional configuration of a wireless communication device according to this embodiment. In Fig. 17, the same reference numerals are given to the same parts as in Fig. 7 and Fig. 12 described above, and detailed description thereof will be omitted.

[0141] 17, the wireless communication device 20 includes a movement detection unit 25. Note that the movement detection unit 25 may be realized by software, may be realized by hardware, or may be realized by a configuration in which software and hardware are combined.

[0142] The movement detection unit 25 detects whether the wireless communication device 20 is moving or not. Note that whether the wireless communication device 20 is moving or not can be detected based on acceleration data measured by an acceleration sensor mounted on the wireless communication device 20.

[0143] The detection result by the movement detection unit 25 is output to the slot setting unit 23 and is used when the slot setting unit 23 changes the setting of the reception slot of the wireless communication device 20 .

[0144] Hereinafter, an example of a processing procedure of the wireless communication device 20 will be described with reference to the flowchart of Fig. 18. In the following description, the wireless communication device 20 that executes the processing shown in Fig. 18 will be referred to as a target wireless communication device 20.

[0145] First, the processes of steps S21 to S27 corresponding to the processes of steps S1 to S7 shown in FIG. 8 described above are executed.

[0146] If it is determined that the slot in which the reception process was executed is the last slot (YES in step S27), the movement detection unit 25 included in the wireless communication device 20 detects whether the wireless communication device 20 is moving or not based on, for example, acceleration data measured by an acceleration sensor mounted on the wireless communication device 20. The slot setting unit 23 determines whether the wireless communication device 20 is moving or not based on the detection result by the movement detection unit 25 (step S28).

[0147] If it is determined that the wireless communication device 20 is moving (YES in step S28), the slot setting unit 23 executes the second slot change process (step S29). Note that the second slot change process is as described in the first embodiment, and therefore a detailed description thereof will be omitted here.

[0148] However, when the second slot change process is executed in this embodiment, for example, as shown in FIG. 19, the wireless communication device 20 (wireless communication device 20-3) is moving, and it is difficult to identify other nodes (aggregation device 10, wireless communication devices 20-1, and 20-2) with which the wireless communication device 20 can communicate. For this reason, in the second slot change process executed in this embodiment, for example, the first slot of multiple slots (transmission slots of other nodes) is set as the reception slot of the wireless communication device 20. In other words, in the second slot change process in this embodiment, since there is a high possibility that other nodes with good communication quality (i.e., other nodes in the vicinity of the wireless communication device 20) will change, the reception slot is changed so that reception processing is started from the node with the earliest data transmission timing within the communication period so that reception processing can be executed in sequence in the transmission slots of all other nodes.

[0149] On the other hand, if it is determined that the wireless communication device 20 is not moving (NO in step S28), the slot setting unit 23 executes a third slot change process (step S30). Note that the third slot change process is as described in the second embodiment, and therefore a detailed description thereof will be omitted here.

[0150] As described above, in this embodiment, when it is determined that data is not received in the last slot (second slot) in a communication cycle, for example, it is determined whether or not the wireless communication device 20 is moving. Also, other than when it is determined that data is not received in the last slot, it may be determined whether or not the wireless communication device 20 is moving after step S23 or step S25, and slot change processing may be performed.

[0151] In this embodiment, when it is determined that the wireless communication device 20 is moving, the first slot of the multiple slots is set as the reception slot of the wireless communication device 20 (the slot for receiving data transmitted from other nodes in the second period).

[0152] Furthermore, in this embodiment, when it is determined that the wireless communication device 20 is not moving, the location of the wireless communication device 20 is acquired, and the transmission slot of another node close to the location of the wireless communication device 20 (the third slot in which the other node transmits data) is set as the reception slot of the wireless communication device 20.

[0153] In this embodiment, with such a configuration, when the wireless communication device 20 does not receive data, if the wireless communication device 20 is moving, there is a high possibility that other nodes that can properly receive data will change, so the reception slot is changed so that reception processing is performed for all other nodes, and if the wireless communication device 20 is not moving, the reception slot is changed so that data is received from other nearby nodes that are assumed to have good communication quality. With this, even if data cannot be received in the reception slot due to the wireless communication device 20 moving (i.e., a disconnection occurs), it is possible to change the reception slot according to the status of the wireless communication device 20 (the mobile body in which the wireless communication device 20 is installed) and avoid an increase in power consumption.

[0154] In this embodiment, it has been described that whether or not the wireless communication device 20 is moving is detected based on acceleration data measured by an acceleration sensor mounted on the wireless communication device 20. However, whether or not the wireless communication device 20 is moving may also be detected based on a change in the position of the wireless communication device 20 indicated by position information acquired using a GPS function, sensor data measured by another sensor mounted on the wireless communication device 20, or the like.

[0155] In addition, when the wireless communication device 20 is installed in an elevator 101, the wireless communication device 20 may be configured to detect whether or not the wireless communication device 20 installed in the elevator 101 is moving based on information indicating the operating status (moving status) of the elevator 101 obtained from an elevator control device.

[0156] Furthermore, when the wireless communication device 20 is installed on a train, the wireless communication device 20 may be configured to detect whether or not the wireless communication device 20 installed on the train is moving, based on information indicating the operation status (movement status) of the train obtained from an operation management system.

[0157] According to at least one of the embodiments described above, it is possible to provide a wireless communication device and method capable of realizing power saving.

[0158] Although some 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 embodiments can be implemented 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 in the scope of the invention and its equivalents described in the claims, as well as in the scope and spirit of the invention. [Explanation of symbols]

[0159] 1...communication system, 10...aggregation device, 20, 20-1 to 20-3...wireless communication device, 20a...microcontroller, 20b...wireless communication module, 20c...sensor, 21...transmission / reception processing unit, 22...determination unit, 23...slot setting unit, 24...position information acquisition unit, 25...movement detection unit, 100...hoistway, 101...elevator, 102...counterweight.

Claims

1. A wireless communication device that forms a network with a plurality of other nodes and operates to receive data transmitted from the other nodes in a first slot of a plurality of slots in a first period, a first determination means for determining whether data has been received in the first slot; a second determination means for determining whether data transmitted from another node has been received in a second slot subsequent to the first slot in the first period when it is determined that no data has been received in the first slot; a setting means for setting the second slot as a slot for receiving data transmitted from another node in a second period following the first period when it is determined that data has been received in the second slot; A wireless communication device comprising:

2. 2. The wireless communication device according to claim 1, wherein the wireless communication device is installed in a moving object that moves so that the distance between the wireless communication device and other nodes changes.

3. 3. The wireless communication device according to claim 2, wherein the wireless communication device is driven by power supplied from a cell or a battery.

4. 2. The wireless communication device according to claim 1, wherein the setting means sets a third slot, which is earlier than the first slot, as a slot for receiving data transmitted from another node in the second period when it is determined that no data is received in the second slot.

5. 5. The wireless communication device according to claim 4, wherein the third slot is the slot immediately preceding the second slot.

6. The wireless communication device according to claim 4 , wherein the third slot is a first slot of the plurality of slots.

7. and acquiring a position of the wireless communication device when it is determined that no data is received in the second slot; The setting means sets a third slot in which another node close to the acquired position transmits data as a slot for receiving data transmitted from the other node in the second period.

3. The wireless communication device according to claim 2.

8. a third determination means for determining whether the wireless communication device is moving when it is determined that no data has been received in the second slot; an acquisition means for acquiring a location of the wireless communication device when it is determined that the wireless communication device is not moving; Further comprising: The setting means is When it is determined that the wireless communication device is moving, a first third slot among the plurality of slots is set as a slot for receiving data transmitted from another node in the second period. When the position of the wireless communication device is acquired, a third slot in which another node close to the position of the wireless communication device transmits data is set as a slot for receiving data transmitted from the other node in the second period.

3. The wireless communication device according to claim 2.

9. The wireless communication device according to any one of claims 4 to 8, wherein the second slot is the last slot of the plurality of slots.

10. The wireless communication device according to claim 1 , wherein the data includes acknowledgement information for the data transmitted from the wireless communication device.

11. The first determination means determines whether the data has been received based on a received signal strength of the data received in the first slot, The second determination means determines whether the data has been received based on a received signal strength of the data received in the second slot.

2. The wireless communication device of claim 1.

12. The first determination means determines whether the data has been received based on the number of times the data has been received in the first slot in each of a plurality of first periods; The second determination means determines whether the data has been received based on the number of times the data has been received in the second slot in each of the plurality of first periods.

2. The wireless communication device of claim 1.

13. A method executed by a wireless communication device that is part of a network with a plurality of other nodes and that operates to receive data transmitted from the other nodes in a first slot of a plurality of slots in a first period, the method comprising: determining whether data is received in the first slot; when it is determined that data has not been received in the first slot, determining whether data transmitted from another node has been received in a second slot subsequent to the first slot in the first period; when it is determined that data has been received in the second slot, setting the second slot as a slot for receiving data transmitted from another node in a second period that is next to the first period; A method comprising the steps of:

Images