Wireless communication system and method for controlling the wireless communication system

Abstract

When an application system uses a wireless communication system to acquire necessary data, the system aims to reduce power consumption while enabling the application system to acquire the latest data values ​​at predetermined system cycles. [Solution] The application system is required to acquire the latest data value at predetermined system cycles. The data is transmitted from slave devices 30A, 30B, 40A, 40B, and 50A to the master device 20. The master device and slave devices are configured to communicate wirelessly multiple times within the system cycle. When the application system successfully acquires data during the predetermined number of wireless communication sessions, the master device transmits success information to the slave devices. Upon receiving the success information, the slave devices stop the remaining wireless communication sessions.

Description

Technical Field

[0001] The present disclosure relates to a wireless communication system used for a predetermined application system to acquire necessary data, and a control method for the wireless communication system.

Background Art

[0002] For example, Patent Document 1 describes a technique for reducing the power consumption of a communication system operating with a finite power source. In the communication system of this Patent Document 1, a sleep control unit of an access point estimates the remaining amount of the battery after BLE communication by subtracting the unit power amount, which is the power amount required for one BLE communication, from the remaining amount of the battery of the access point. Based on the estimated remaining amount, the sleep control unit refers to a correspondence table and calculates the charging time required for the remaining amount of the battery to increase to the unit power amount. The correspondence table shows the remaining amount of the battery when charged for various charging times from various estimated remaining amounts. The sleep control unit determines the calculated charging time as the shortest sleep period.

[0003] The access point shifts to the sleep state during the determined shortest sleep period to charge the battery. As a result, the access point can return from the sleep state in a state where at least one BLE communication can be performed. Further, the access point includes the determined shortest sleep period in the communication signal of the BLE communication and transmits it to the wireless terminal. The wireless terminal enters the sleep state during the received shortest sleep period. Thus, since the wireless terminal also enters the sleep state during the shortest sleep period, the power consumption in the wireless terminal can also be reduced.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

[0005] As described above, the communication system described in Patent Document 1 determines the shortest sleep period based on the remaining charge of the battery in the access point, and the access point and wireless terminal enter a sleep state during that shortest sleep period.

[0006] In this scenario, a wireless communication system may be used to obtain data required by a specific application system. In this case, the wireless communication system includes a master node and at least one slave node, and data may be transmitted from the slave node to the master node. The application system may then be required to obtain the latest data via wireless communication between the master node and the slave node at predetermined system cycles to perform monitoring, warning, or other processing, depending on the circumstances at the time.

[0007] However, if the communication system technology described in Patent Document 1 is used to save power in a wireless communication system while a predetermined application system acquires the necessary data, the sleep period is determined based on the remaining battery charge. As a result, the application system may not be able to acquire the latest data values ​​at predetermined system cycles.

[0008] This disclosure is made in view of the above-mentioned points, and aims to provide a wireless communication system and a control method for a wireless communication system that enable an application system to acquire the latest data values ​​at predetermined system cycles while reducing power consumption, when the application system uses the wireless communication system to acquire the necessary data. [Means for solving the problem]

[0009] To achieve the above objective, the wireless communication system provided in this disclosure is a wireless communication system used by a predetermined application system to acquire necessary data, At least one master node (20), It includes at least one slave node (30A, 30B, 40A, 40B, 50A), The master node and slave node are used for bidirectional wireless communication. The data is sent from the slave node to the master node. The application system is required to acquire the latest data values ​​at predetermined system cycles. The master node and slave node are configured to communicate wirelessly multiple times within the system cycle. The master node, after a predetermined number of wireless communication attempts, transmits success information to the slave node when the application system successfully acquires data. Upon receiving success information, the slave node stops the remaining radio communications in a series of radio communications.

[0010] Furthermore, the control method for a wireless communication system provided in this disclosure is a control method for a wireless communication system used by a predetermined application system to acquire necessary data, The wireless communication system comprises at least one master node (20) and at least one slave node (30A, 30B, 40A, 40B, 50A), The master node and slave node are used for bidirectional wireless communication. The data is sent from the slave node to the master node. The application system is required to acquire the latest data values ​​at predetermined system cycles. The master node and slave node are configured to communicate wirelessly multiple times within the system cycle. The master node transmits success information to the slave node when the application system successfully acquires data during a predetermined number of wireless communications, and The slave node includes the ability to stop the remaining radio communications of multiple radio communications upon receiving success information.

[0011] According to the wireless communication system and control method for the wireless communication system described herein, the master node and the slave node are configured to communicate wirelessly multiple times within a system cycle. Although wireless communication is more prone to communication errors than wired communication, multiple wireless communication attempts increase the probability that the application system can obtain the latest data values ​​at each system cycle.

[0012] Furthermore, according to the wireless communication system and control method of the wireless communication system disclosed herein, the master node transmits success information to the slave node when the application system successfully acquires data during a predetermined number of wireless communication sessions. The slave node then stops the remaining wireless communication sessions in response to receiving the success information. As a result, the application system can acquire the latest data values ​​at predetermined system cycles while reducing power consumption in the slave node.

[0013] The reference numbers in parentheses above are merely examples of correspondences with specific configurations in embodiments described later, in order to facilitate understanding of this disclosure, and are not intended to limit the scope of this disclosure in any way.

[0014] Furthermore, technical features described in each claim of the patent claims, other than those described above, will become clear from the description of the embodiments and the accompanying drawings, which will be discussed later. [Brief explanation of the drawing]

[0015] [Figure 1]It is a configuration diagram showing an example of the configuration of an in-vehicle system equipped with a plurality of application systems that operate using a wireless communication system. [Figure 2] It is a schematic configuration diagram schematically showing the software and hardware configurations of various application systems. [Figure 3] It is a diagram showing an example of the relationship between the system cycle and the communication cycle of wireless communication between the master device and the slave device. [Figure 4] It is a flowchart showing an example of the processing executed in an application system including a wireless communication system. [Figure 5] It is a flowchart showing an example of the details of the transmission frame creation process in the flowchart of FIG. 4. [Figure 6] It is a diagram showing an example of a transmission frame. [Figure 7] It is a flowchart showing an example of the details of the standby availability determination process in the flowchart of FIG. 4. [Figure 8] It is a flowchart showing an example of the processing for transmitting to the master side when an abnormality is detected in the slave-side application. [Figure 9] It is a diagram showing an example of instructing any one of the standby state, the sleep state, and the deep sleep state to the slave-side communication software / hardware according to the number of remaining cycles.

Mode for Carrying Out the Invention

[0016] Hereinafter, preferred embodiments of the present disclosure will be described with reference to the drawings. Note that for the same or similar configurations, the same reference numerals may be given in multiple drawings, and the description may be omitted in some cases. When only a part of the configuration is described in each embodiment, the configuration of the other part of the said configuration can apply the configuration of other embodiments described previously. Also, not only the combinations of configurations explicitly shown in the description of each embodiment, but also the configurations of multiple embodiments can be partially combined with each other as long as there is no problem with the combination.

[0017] (First Embodiment) The wireless communication system according to this embodiment includes at least one master device (also referred to as a master node) and at least one slave device (also referred to as a slave node). At least one of the master device and the slave device may be mounted on a vehicle. In this case, at least the slave device may operate using power supplied by a battery. Vehicles include, for example, automobiles, trucks, construction vehicles, motorcycles, and railway vehicles.

[0018] Figure 1 shows an example of the configuration of an in-vehicle system 100 equipped with multiple application systems that operate using a wireless communication system 10 according to this embodiment. As shown in Figure 1, in the in-vehicle system 100, the wireless communication system 10 can be applied to various application systems. In this case, each of the multiple slave devices 30A, 30B, 40A, 40B, and 50A is associated with one of the application systems.

[0019] For example, the wireless communication system 10 can be applied as one of the application systems to a battery monitoring system that monitors the status of batteries mounted as battery packs in electric vehicles such as electric vehicles, hybrid vehicles, and plug-in hybrid vehicles. When the wireless communication system 10 is applied to a battery monitoring system, for example, at least one master device 20 is connected to a first application control device 1 which has the function of a monitoring and control device. In addition, multiple first application slave devices 30A, 30B are provided in each of the multiple battery stacks that make up the battery pack and are connected to first application devices 35A, 35B which have the function of detection devices. In this case, the multiple first application slave devices 30A, 30B operate using power supplied from the corresponding battery stacks. Both the master device 20 and the multiple first application slave devices 30A, 30B are mounted in the vehicle.

[0020] Each battery stack is equipped with a detection device (first application device 35A, 35B) that detects battery information such as the voltage and current of each battery cell in the corresponding battery stack, and the temperature of the battery stack, using various sensors. Then, upon receiving a packet requesting battery information from the first application control device 1, which is a monitoring and control device, via the wireless communication system 10, the first application devices 35A, 35B transmit a packet containing the detected battery information to the first application control device 1 via the wireless communication system 10.

[0021] The first application control device 1 calculates the total state of charge (SOC) of the battery stack based on the received battery information, and determines whether it is necessary to drive the heating / cooling mechanism to adjust the temperature of the battery pack to an appropriate range, and whether it is necessary to perform a so-called equalization process to equalize the voltage of each battery cell in the battery stack. For example, if the first application control device 1 determines that equalization processing is necessary in at least one battery stack, it can instruct the corresponding first application devices 35A and 35B to perform the equalization process via the wireless communication system 10. In addition, the first application devices 35A and 35B perform processing to determine abnormalities in various sensors and abnormalities in their own operation, and if an abnormality is detected, they can transmit the abnormality information to the first application control device 1 via the wireless communication system 10.

[0022] Furthermore, the wireless communication system 10 according to this embodiment can be applied to other application systems, such as a smart key (registered trademark, hereinafter the same) system or a tire pressure monitoring system. When the wireless communication system 10 is applied to a smart key system, for example, the master device 20 is mounted on a vehicle and connected to a second application control device 2 which has the function of an in-vehicle unit that controls the locking and unlocking of vehicle doors and the on / off switching of power sources such as the vehicle's engine. The second application slave device 40A is mounted on an electronic key, which is a second application device 45A. In this case, the second application slave device 40A operates using power supplied from a battery built into the electronic key, for example.

[0023] When the second application device 45A receives a request signal from the second application control device 2, it sends a response signal back via the second application slave device 40A. In the smart key system, this response signal is the data required by the application system. Based on this response signal, the second application control device 2 can estimate the distance to the electronic key.

[0024] Furthermore, multiple other second application slave devices 40B may be positioned at various locations on the vehicle, such as the front, sides, and rear. The multiple second application slave devices 40B positioned at various locations on the vehicle have the function of intercepting communication between the master device 20 and the second application slave device 40A mounted on the electronic key, and transmitting the intercepted communication results to the master device 20. The multiple second application slave devices 40B may be wired to the master device 20. The second application control device 2 can detect the position of the electronic key with high precision using positioning techniques such as multi-sided surveying or polygonal surveying, based on the positions of the multiple second application slave devices 40B, the time at which the multiple second application slave devices 40B intercepted communications, and / or the arrival angles of the communication signals in the multiple second application slave devices 40B.

[0025] When the wireless communication system 10 is applied to a tire pressure monitoring system, the master device 20 is connected to a third application control device 3 mounted on the vehicle, which functions as a monitoring unit that displays tire pressure and provides warnings if the pressure is abnormal. Multiple third application slave devices 50A are connected by wire or wireless to tire pressure detection devices (third application equipment 55A) installed in each tire. In this case, the multiple third application slave devices 50A operate using power supplied from batteries built into each of them, for example. The air pressure detected by the third application equipment 55A is then transmitted to the third application control device 3 via the wireless communication system 10 in response to a data request command from the third application control device 3. Based on the received air pressure, the third application control device 3 can display the tire pressure and provide warnings if the air pressure is abnormal.

[0026] Note that the configuration shown in Figure 1 is merely one example of this disclosure. For example, the in-vehicle system 100 according to this disclosure does not need to include all application systems for the battery monitoring system, smart key system, and tire pressure monitoring system, and may have a configuration with at least one application system. Also, in the configuration shown in Figure 1, a wireless communication system 10 is provided for multiple application systems, including one master device 20 and multiple slave devices 30A, 30B, 40A, and 50A. However, the wireless communication system 10 may also include multiple master devices 20. If multiple master devices 20 are provided, the multiple master devices 20 may communicate with different slave devices 30A, 30B, 40A, and 50A for each application system, for example. Alternatively, multiple master devices 20 may communicate with the same multiple slave devices 30A, 30B, 40A, and 50A. Furthermore, in the configuration shown in Figure 1, the control devices 1, 2, and 3 for the multiple application systems are provided separately, but the functions of two or more control devices may be integrated into a single control device.

[0027] The following describes the configuration of a wireless communication system 10 applied to a battery monitoring system, which is one of the application systems. Wireless communication systems 10 applied to other application systems can be configured similarly.

[0028] The wireless communication system 10 applied to the battery monitoring system comprises a master device 20 and first application slave devices 30A and 30B. The master device 20 and the first application slave devices 30A and 30B can communicate wirelessly, for example, in accordance with the Bluetooth Low Energy (Bluetooth is a registered trademark, the same applies hereinafter, and hereinafter Bluetooth Low Energy will be referred to as Bluetooth LE) communication standard. When communicating wirelessly in accordance with the Bluetooth LE communication standard, the details of the communication method related to communication connection and encrypted communication may be carried out in accordance with the sequence specified in the Bluetooth LE standard. However, the master device 20 and the first application slave devices 30A and 30B may communicate wirelessly in accordance with other wireless communication standards, such as ultra-wideband (UWB) wireless communication or Wi-Fi® wireless communication.

[0029] As shown in Figure 1, the master device 20 includes a control circuit (CNT) 21, a wireless communication circuit (WC) 22, and an antenna 23. In addition to the elements described above, the master device 20 may also include input / output interfaces and bus lines for wired or wireless communication with devices other than the first application slave devices 30A and 30B.

[0030] The control circuit 21 is, for example, a computer comprising a processor 211 and memory 212. The memory 212 includes, for example, RAM and ROM. RAM is an abbreviation for Random Access Memory. ROM is an abbreviation for Read Only Memory. In the control circuit 21, the processor 211 executes software processing related to wireless communication, such as connection establishment processing between the master device 20 and the first application slave devices 30A and 30B, encryption processing and decryption processing, by executing a program stored in ROM while using RAM as a temporary storage area. The processor 211 may be singular or plural. The program storage medium is not limited to ROM. Various storage media such as HDDs and SSDs can be used. HDD is an abbreviation for Hard-disk Drive. SSD is an abbreviation for Solid State Drive.

[0031] The processor 211 can be, for example, a CPU, MPU, GPU, or DFP. CPU is an abbreviation for Central Processing Unit. MPU is an abbreviation for Micro-Processing Unit. GPU is an abbreviation for Graphics Processing Unit. DFP is an abbreviation for Data Flow Processor. The control circuit 21 may be implemented by combining multiple types of processing units, such as a CPU, MPU, and GPU. Alternatively, the control circuit 21 may be implemented as an SoC. SoC is an abbreviation for System on Chip. The control circuit 21 may also be implemented using an ASIC or FPGA. ASIC is an abbreviation for Application Specific Integrated Circuit. FPGA is an abbreviation for Field-Programmable Gate Array.

[0032] The wireless communication circuit 22 includes an RF circuit (not shown) for wirelessly transmitting and receiving packets. The wireless communication circuit 22 has a transmitting function that modulates the transmission signal and oscillates at the frequency of the RF signal. The wireless communication circuit 22 also has a receiving function that demodulates the received signal. RF is an abbreviation for radio frequency.

[0033] More specifically, the wireless communication circuit 22 modulates a packet containing data output from the control circuit 21 and transmits it to the first application slave devices 30A and 30B via the antenna 23 using an RF circuit. The control circuit 21 outputs a packet containing data such as a request command, encrypted using, for example, encryption information exchanged during the connection establishment process, to the wireless communication circuit 22. Encryption enhances the confidentiality of the data. However, the connection establishment process and / or encryption process do not have to be performed. For example, the control circuit 21 of the master device 20 may synchronize the communication timing with the first application slave devices 30A and 30B and perform transmission and reception at that communication timing. Alternatively, the master device may transmit a packet containing data such as a request command without performing encryption.

[0034] The wireless communication circuit 22 can add data necessary for wireless communication (e.g., communication control information) to the transmission packets. This data may include, for example, an identifier (ID), a sequence number, the next sequence number, and an error detection code. The wireless communication circuit 22 may also control the data size, communication format, schedule, and error detection for communication between the master device 20 and the first application slave devices 30A and 30B. These communication-related controls may be performed by the control circuit 21.

[0035] Furthermore, the wireless communication circuit 22 receives packets containing data transmitted from the first application slave devices 30A and 30B via the antenna 23 and demodulates them. It then transmits the demodulated packets to the control circuit 21. The control circuit 21 can extract data from the demodulated packets by performing decoding and other processing. The antenna 23 converts electrical signals into radio waves and radiates them into space. The antenna 23 also receives radio waves propagating in space and converts them into electrical signals.

[0036] Multiple slave devices 30A and 30B for the first application each have the same configuration. Therefore, the configuration and operation of the slave device 30A for the first application will be described below as a representative example.

[0037] As shown in Figure 1, the slave device 30A for the first application includes a control circuit (CNT) 31, a wireless communication circuit (WC) 32, and an antenna 33. In addition to the elements described above, the slave device 30A for the first application may also include input / output interfaces and bus lines for wired or wireless communication with devices other than the master device 20. The control circuit 31 has a configuration similar to the control circuit 21 of the master device 20. The control circuit 31 includes, for example, a processor 311 and a memory 312. The memory 312 includes, for example, RAM and ROM.

[0038] The control circuit 31 can extract request commands and other information from packets acquired via the wireless communication circuit 32 by performing decryption processing, etc. The extracted request commands are sent to the first application device 35A. This allows the first application device 35A to perform the requested processing (such as response processing, such as acquiring and returning the requested data, or execution processing of the requested processing) based on the request commands. For example, if the request command contained in the received packet is a request to transmit battery information, the first application device 35A detects the battery information of the corresponding battery stack and transmits the detected battery information to the control circuit 31. Then, as a response to the request command, the control circuit 31 transmits a packet containing encrypted data using encrypted information including the detected battery information to the wireless communication circuit 32. Even in this case, encryption processing does not necessarily have to be performed.

[0039] The wireless communication circuit 32 includes an RF circuit (not shown) for wirelessly transmitting and receiving packets. Similar to the wireless communication circuit 22, the wireless communication circuit 32 has both transmitting and receiving functions. The wireless communication circuit 32 receives packets transmitted from the master device 20 via the antenna 33 and demodulates them. It then transmits the demodulated packets to the control circuit 31. The wireless communication circuit 32 modulates packets containing data transmitted from the control circuit 31 and transmits them back to the master device 20 via the antenna 33. The wireless communication circuit 32 can add data necessary for wireless communication, such as communication control information, to the transmitted packets. The wireless communication circuit 32 may control the data size, communication format, schedule, and error detection of communication between the master device 20 and the first application slave device 30A. These communication-related controls may be performed by the control circuit 31. The antenna 33 converts electrical signals into radio waves and radiates them into space. The antenna 33 also receives radio waves propagating through space and converts them into electrical signals.

[0040] As described above, the first application control device 1 and the first application device 35A, which constitute the battery monitoring system, utilize bidirectional wireless communication in the wireless communication system 10. The first application control device 1 then acquires battery information and other data necessary for the battery monitoring system from the first application device 35A.

[0041] Figure 2 schematically shows the software and hardware configurations of various application systems. In Figure 2, the "application" on the master side corresponds to, for example, the software of the first application control device 1. The "communication software" on the master side corresponds to the software executed by the control circuit 21 of the master device 20. The "hardware" on the master side corresponds to the wireless communication circuit 22. Furthermore, the "application" on the slave side corresponds to, for example, the software of the first application device 35A. The "communication software" on the slave side corresponds to, for example, the software executed by the control circuit 31 of the first application slave device 30A. The "hardware" on the slave side corresponds to, for example, the wireless communication circuit 32 of the first application slave device 30A.

[0042] In this embodiment, the slave-side "application," for example, the first application device 35A, outputs a standby command, which causes the slave-side "communication software" and "hardware," for example, the control circuit 31 and wireless communication circuit 32 of the first application slave device 30A, to switch to standby mode and stop their respective operations. When the control circuit 31 and wireless communication circuit 32 of the first application slave device 30A switch to standby mode, it becomes possible to reduce the power consumption of the first application slave device 30A.

[0043] Here, the various application systems described above are required to obtain the latest values ​​of the data they need at predetermined system cycles via wireless communication between the master device 20 and the slave devices 30A, 30B, 40A, 40B, and 50A in order to monitor, warn, or perform other processing depending on the circumstances at the time. The predetermined system cycle may differ for each application system. Generally, if the data to be monitored or warned about changes in a short period of time, the system cycle may be set shorter compared to if it changes over a longer period of time. Also, the greater the impact on vehicle operation and safety, the shorter the system cycle may be set. In other words, application systems that require high reliability of the data may have a shorter system cycle than application systems that can tolerate lower reliability.

[0044] To obtain the data required by various application systems, the master device 20 and each of the slave devices 30A, 30B, 40A, 40B, and 50A communicate via bidirectional wireless communication. Wireless communication is more prone to communication errors than wired communication. Therefore, in this embodiment, the master device 20 and each of the slave devices 30A, 30B, 40A, 40B, and 50A are configured to communicate wirelessly multiple times within the system cycle of the corresponding application system. This increases the probability that various application systems can obtain the latest data values ​​for each system cycle.

[0045] Furthermore, the number of wireless communications per system cycle may vary depending on the type of application system. For example, an application system that requires high data reliability may have a higher number of wireless communications per system cycle compared to an application system that only requires low reliability.

[0046] Figure 3 shows an example of the relationship between the system cycle and the communication cycle of wireless communication between the master device 20 and each of the slave devices 30A, 30B, 40A, 40B, and 50A. Figure 3 shows an example in which three wireless communications are performed within one system cycle. In each communication cycle, the master device 20 first sends a packet containing a request command. Each of the slave devices 30A, 30B, 40A, 40B, and 50A receives the packet containing the request command and sends back the requested data.

[0047] As shown in the "Comparative Example" in the upper part of Figure 3, if the application system successfully acquires the necessary data during the first communication cycle of wireless communication, the application will have already acquired the latest data for that system cycle. Therefore, as shown in the "Comparative Example" in Figure 3, there is little need for the slave devices 30A, 30B, 40A, 40B, and 50A to transmit further data in subsequent communication cycles.

[0048] Therefore, in the wireless communication system 10 according to this embodiment, the master device 20 is configured to transmit success information to the slave devices 30A, 30B, 40A, 40B, and 50A when the application system successfully acquires data in a predetermined number of wireless communication sessions. The slave devices 30A, 30B, 40A, 40B, and 50A are configured to switch to a standby state and stop the remaining wireless communication sessions in the multiple wireless communication sessions upon receiving the success information. This allows the application system to acquire the latest data values ​​at predetermined system cycles while reducing the power consumption of the slave devices 30A, 30B, 40A, 40B, and 50A. As a result, when the slave devices 30A, 30B, 40A, 40B, and 50A are powered by batteries, the operating time of the slave devices 30A, 30B, 40A, 40B, and 50A can be extended.

[0049] The "Example" section in the lower part of Figure 3 shows an example of a communication sequence using the wireless communication system 10 according to this embodiment. In the "Example" in Figure 3, if the application system successfully acquires the necessary data during the first communication cycle of wireless communication, success information is transmitted from the master device 20 during the second communication cycle of wireless communication. Figure 3 also shows an example where slave devices 30A, 30B, 40A, 40B, and 50A return an acknowledgment upon receiving the success information. However, this return of an acknowledgment is not required.

[0050] In the "Example" shown in Figure 3, since success information was received during the second communication cycle of wireless communication, the slave devices 30A, 30B, 40A, 40B, and 50A remain in standby mode during the third communication cycle. Therefore, they neither receive request commands from the master device 20 nor transmit data. In this way, the slave devices 30A, 30B, 40A, 40B, and 50A cease all operations related to transmission and reception.

[0051] Figure 3 shows the communication sequence when the master device 20 communicates with one slave device 30A, 30B, 40A, 40B, 50A. When the master device 20 communicates with multiple slave devices 30A, 30B, 40A, 40B, 50A, for example, a communication period (sub-communication cycle) can be assigned to each of the multiple slave devices 30A, 30B, 40A, 40B, 50A that need to communicate during each communication cycle.

[0052] As described above, the wireless communication system 10 according to this embodiment requires two communication cycles for sending and receiving data required by the application system and for sending and receiving success information. Therefore, the slave devices 30A, 30B, 40A, 40B, and 50A can enter a standby state from the third communication cycle at the earliest. For this reason, in this embodiment, the number of communication cycles per system cycle is set to three or more.

[0053] Next, an example of processing performed in the application system including the wireless communication system 10 will be explained with reference to the flowchart in Figure 4. The processing shown in the flowchart in Figure 4 is performed at each communication cycle. Furthermore, if multiple application systems are installed in the vehicle, the processing shown in the flowchart in Figure 4 is performed in each application system.

[0054] Furthermore, when the master device 20 and the slave devices 30A, 30B, 40A, 40B, and 50A perform wireless communication according to, for example, the Bluetooth LE communication standard, a connection establishment process may be performed before executing the process shown in the flowchart of Figure 4. In the connection establishment process, for example, the slave devices 30A, 30B, 40A, 40B, and 50A perform an advertising operation, sending an advertising signal via an advertising communication channel. The master device 20 performs a scan operation to scan for the advertising signal. The advertising communication channel includes multiple communication channels (for example, three in the case of Bluetooth LE). When the master device 20 receives an advertising signal on any of the communication channels through the scan operation, it sends a connection request to the slave devices 30A, 30B, 40A, 40B, and 50A that sent the advertising signal. When this connection request is received by the slave devices 30A, 30B, 40A, 40B, and 50A, a communication connection is established between the master device 20 and the slave devices 30A, 30B, 40A, 40B, and 50A.

[0055] After a communication connection is established, the master device 20 and the slave devices 30A, 30B, 40A, 40B, and 50A exchange connection information. In this exchange of connection information, the master device 20 and the slave devices 30A, 30B, 40A, 40B, and 50A can exchange encryption information used for wireless communication and share initial information regarding frequency channel hopping. The initial information includes, for example, a hopping pattern or a function for hopping.

[0056] In step S100 of the flowchart in Figure 4, the master application (for example, the control device 1 for the first application) executes the process of creating a transmission frame. An example of the details of the transmission frame creation process is shown in the flowchart in Figure 5. The transmission frame creation process will be explained below with reference to the flowchart in Figure 5.

[0057] As described above, the master application sends a request command to the application requesting the data required by the application system. In the transmission frame creation process, a transmission frame is created that includes the request command as shown in Figure 6, and if the master application successfully acquires the data, it also includes success information, and further includes the number of remaining communication cycles that the slave devices 30A, 30B, 40A, 40B, and 50A can stop operating. The format of the transmission frame is not limited to the example shown in Figure 6. For example, it is also possible for the master to directly create packets to send to the slave devices 30A, 30B, 40A, 40B, and 50A without creating a transmission frame.

[0058] In step S500 of the flowchart in Figure 5, the master application determines whether or not data acquisition has been successful. The data acquisition success determination is performed in step S140 of the flowchart in Figure 4, which will be described later. If it is determined that data acquisition has been successful, the master application proceeds to step S510. On the other hand, if it is determined that data acquisition has not been successful, the master application proceeds to step S520.

[0059] In step S510, the master application writes a "1" to the success information bit of the transmission frame to indicate that data acquisition was successful. On the other hand, in step S520, the master application writes a "0" to the success information bit of the transmission frame to indicate that data acquisition has not yet been successful.

[0060] In step S530, the master application performs communication for a total of N communications. cnt This counts the number of communications. For example, if it is the first communication cycle since the system cycle began, the number of communications would be N. cnt = counted as 1. In step S540, the master application calculates the remaining cycle X, which is the number of remaining communication cycles that slave devices 30A, 30B, 40A, 40B, and 50A can stop operating. For example, if the number of communication cycles per system cycle is N thr Therefore, the remaining period X can be calculated by the following formula 1. The processing in steps S530 and S540 corresponds to the calculation unit of this disclosure. (Math 1)X=N thr -N cnt -1 The reason for subtracting 1 is that in the next communication cycle, the master device 20 will send success information to the slave devices 30A, 30B, 40A, 40B, and 50A, and therefore the number of communication cycles in which the slave devices 30A, 30B, 40A, 40B, and 50A can stop operating needs to be reduced accordingly.

[0061] In step S550, the master application determines whether the remaining period X is greater than 0. If it determines that the remaining period X is greater than 0, the master application proceeds to step S560. On the other hand, if it determines that the remaining period X is 0, the master application proceeds to step S570.

[0062] In step S560, the master application writes the calculated remaining period "X" to the remaining period bit of the transmission frame. On the other hand, in step S570, the master application writes "0" to the remaining period bit of the transmission frame.

[0063] In the flowchart in Figure 5, the remaining period X was calculated and written to the remaining period bit of the transmission frame, regardless of whether the data acquisition success determination had been made. However, it is also possible to calculate the remaining period X and write the calculated remaining period X to the remaining period bit only if the data acquisition success determination has been made. In this case, if the data acquisition success determination has not been made, a constant value that does not represent the remaining period, such as "0", may be written to the remaining period bit. Also, in the flowchart in Figure 5, an example was shown in which the master application counts up the number of communication cycles Ncnt for each communication performed. However, the master application counts up the number of communication cycles per system cycle N for each communication performed. thr You can also count down from that point. In this case, the remaining period X can be found by subtracting 1 from the number of steps after the countdown.

[0064] Returning to the flowchart in Figure 4, let's continue the explanation. In step S110, the master application instructs the master communication software / hardware (corresponding to the master device 20) to send the created transmission frame to the corresponding slave devices 30A, 30B, 40A, 40B, and 50A.

[0065] In step S200, the master-side communication software / hardware receives a transmission instruction, including the transmission frame, from the master-side application. In step S210, the master-side communication software / hardware creates a packet based on the transmission frame. Then, the master-side communication software / hardware modulates the created packet and transmits it.

[0066] In step S300, the slave-side communication software / hardware (corresponding to slave devices 30A, 30B, 40A, 40B, and 50A) demodulates and receives packets transmitted from the master-side communication software / hardware. In step S310, the slave-side communication software / hardware forwards the received packets to the slave-side application.

[0067] In step S400, the slave application receives the forwarded packet. Then, in step S410, the slave application determines whether to transition to the standby state based on the success information bits contained in the received packet. An example of the details of this standby status determination process is shown in the flowchart of Figure 7. The standby status determination process will now be explained with reference to the flowchart in Figure 7.

[0068] In step S600, the slave application determines whether the value of the success information bit in the received packet is "1". If it determines that the value of the success information bit is "1", the slave application proceeds to step S610. On the other hand, if it determines that the value of the success information bit is not "1", the slave application proceeds to step S640.

[0069] In step S610, the slave application obtains the remaining period X from the remaining period bits contained in the received packet. In step S620, the slave application determines whether the obtained remaining period X is greater than 0. If it determines that the remaining period X is greater than 0, the slave application proceeds to step S630. On the other hand, if it determines that the remaining period X is 0, the slave application proceeds to step S640.

[0070] In step S630, the slave application determines that it can transition to standby mode. On the other hand, in step S640, the slave application determines that it cannot transition to standby mode.

[0071] Returning to the flowchart in Figure 4, let's continue the explanation. In step S420, the slave application determines whether to transition to the standby state based on the result of the standby feasibility determination process. If it determines that it is possible to transition to the standby state, the slave application proceeds to step S430. On the other hand, if it determines that it is not possible to transition to the standby state, the slave application proceeds to the process in step S440.

[0072] In step S430, the slave application outputs a standby command to the slave communication software / hardware. At this time, the slave application instructs the slave communication software / hardware on the duration of the standby state based on the remaining cycle X. This allows the slave communication software / hardware to remain in a standby state until the next system cycle begins. The slave application may also instruct the slave communication software / hardware to send an acknowledgment to the master to notify it that it has successfully received a packet with a success information bit of "1".

[0073] In step S440, the slave application obtains data corresponding to the requested command. In step S450, the slave application instructs the communication software / hardware to send the obtained data to the master.

[0074] In step S320, the slave-side communication software / hardware determines whether or not it has received a standby command from the slave-side application. If it determines that it has received a standby command, the slave-side communication software / hardware proceeds to the process in step S330. On the other hand, if it determines that it has not received a standby command, the slave-side communication software / hardware proceeds to the process in step S350.

[0075] In step S330, the slave's communication software / hardware changes settings such as timers and configurations in preparation for transitioning to standby mode. Then, in step S340, the slave's communication software / hardware transitions to standby mode until the next system cycle begins.

[0076] In step S350, the slave-side communication software / hardware receives a transmit command from the slave-side application. In step S360, the slave-side communication software / hardware modulates the packet containing the data acquired by the slave-side application toward the master side and transmits it.

[0077] In step S220, the master's communication software / hardware demodulates and receives the packets transmitted from the slave's communication software / hardware. In step S230, the master's communication software / hardware forwards the received packets to the master's application.

[0078] In step S120, the master application receives the forwarded packet. Then, in step S130, the master application determines whether the data contained in the received packet is normal or not. For example, the master application may store a normal range of data values ​​in advance and determine that the acquired data is normal if it falls within the normal range, and abnormal if it deviates from it. Alternatively, the master application may determine that the change from the previous data is normal if it is within a predetermined value, and abnormal if it exceeds it.

[0079] Furthermore, the master application may also determine that the data contained in the received packet is abnormal if the master's communication software / hardware determines, based on the error detection code contained in the received packet, that the packet was not received correctly.

[0080] If the data is determined to be normal in step S130, the master application proceeds to step S140. In step S140, the master application performs a data acquisition success determination because it has successfully acquired the data. This data acquisition success determination result is referenced in the transmission frame creation process in step S100, as described above. On the other hand, if the data is determined to be abnormal in step S130, the master application terminates the process shown in the flowchart of Figure 4 without performing a data acquisition success determination.

[0081] As described above, the slave devices 30A, 30B, 40A, 40B, and 50A transition to a standby state and stop the remaining wireless communications of multiple wireless communications upon receiving success information from the master side. However, in this embodiment, as shown in Figure 3, even when the slave devices 30A, 30B, 40A, 40B, and 50A are in a standby state, the master device 20 maintains a state in which it can communicate with the slave devices 30A, 30B, 40A, 40B, and 50A. This is to enable the slave-side application (corresponding to application devices 35A, 35B, 45A, and 55A) to transmit abnormal information to the master side if it detects abnormalities in various sensors or abnormalities in its own operation.

[0082] The flowchart in Figure 8 shows an example of the process for sending a notification to the master side when a slave application detects an anomaly. In step S700, the slave application determines whether it has detected a sensor anomaly or an anomaly in its own operation. If an anomaly is detected, the slave application proceeds to the process in step S710. On the other hand, if no anomaly is detected, the slave application terminates the process shown in the flowchart in Figure 8.

[0083] In step S710, it is determined whether the communication software / hardware on the slave side is in standby mode. If it is determined to be in standby mode, the slave application proceeds to step S720. On the other hand, if it is determined not to be in standby mode, the slave application proceeds to step S730.

[0084] In step S720, the slave application outputs a start command to the slave communication software / hardware. This causes the slave communication software / hardware to return from standby to a state where wireless communication is possible. In step S730, the slave application instructs the slave communication software / hardware to transmit abnormal information indicating the detected abnormality.

[0085] While preferred embodiments of this disclosure have been described above, this disclosure is not limited in any way to the embodiments described above and can be implemented in various modified forms without departing from the spirit of this disclosure.

[0086] (Variation 1) In the embodiment described above, when the slave application receives success information from the master, it causes the slave communication software / hardware to switch to a standby state. In the standby state, the slave communication software / hardware stops its respective operations, thus reducing the power consumption of the slave communication software / hardware. However, the slave application may also instruct the slave communication software / hardware to switch to a sleep state instead of a standby state. In this sleep state, for example, power is stopped to the control circuit 31 and at least some of the circuits of the wireless communication circuit on the slave side. This makes it possible to further reduce the power consumption of the slave communication software / hardware.

[0087] (Modification 2) Whether the slave application instructs the slave communication software / hardware to enter a standby or sleep state may be determined based on the number of remaining cycles X. Specifically, the slave application may instruct the slave communication software / hardware to enter a state such that the power consumption of the slave communication software / hardware decreases as the number of remaining cycles X increases.

[0088] For example, Figure 9 shows an example where the communication software / hardware on the slave side is instructed to enter either a standby state, a sleep state, or a deep sleep state depending on the number of remaining cycles X. The difference between the sleep state and the deep sleep state is the range of the circuit over which power is stopped. In the deep sleep state, power to the circuit is stopped over a wider range than in the sleep state. In this way, by switching the state of the communication software / hardware on the slave side according to the remaining cycle X, a greater reduction in power consumption can be obtained as the remaining cycle X increases.

[0089] Furthermore, power consumption decreases in the order of standby, sleep, and deep sleep states, while the time it takes for the slave's communication software / hardware to return to a communication-ready state increases. From this perspective, it is preferable to use the standby state when the remaining period X is short, as this shortens the time it takes to return to a communication-ready state, and to use the sleep or deep sleep state when the remaining period X is longer than that.

[0090] (Variation 3) In the embodiment described above, an example was explained in which the master application calculates the remaining cycle X, which is the number of remaining communication cycles in which the slave communication software / hardware can stop operating. However, instead of calculating the remaining cycle X, the master application may calculate the stop-time in which the slave communication software / hardware can stop operating. The master application can calculate the stop-time in which the slave communication software / hardware can stop operating from the number of remaining cycles and the length of the communication cycle.

[0091] In this case, the slave application may decide whether to instruct the slave's communication software / hardware to enter a standby or sleep state depending on the length of the downtime. Specifically, the slave application may instruct the slave's communication software / hardware to enter a state such that the longer the downtime, the lower the power consumption of the slave's communication software / hardware.

[0092] (Modification 4) In the embodiments and modification 3 described above, an example was explained in which the master-side application calculates the remaining period X and the stop time during which the slave-side communication software / hardware can stop operating. However, it is also possible for the slave-side application to calculate the remaining period X and the stop time during which the slave-side communication software / hardware can stop operating.

[0093] (Variation 5) In modified examples 2 and 3, the slave application determined whether to instruct the slave communication software / hardware to enter standby or sleep mode based on the remaining cycle X or the available downtime. In addition to this, or alternatively, the slave application may also determine whether to instruct the slave communication software / hardware to enter standby or sleep mode based on the vehicle's state, including at least driving and parking. Furthermore, the application system may change the length of the system cycle based on the vehicle's state, including at least driving and parking.

[0094] For example, if the application system is a battery monitoring system, when the vehicle is running, charging and discharging occur in each battery stack of the battery pack due to power supply to the drive motor and power regeneration by the regenerative motor. As a result, the voltage, current, temperature, etc. of each battery stack change moment by moment. For this reason, when the vehicle is running, it is preferable for the application system to shorten the system cycle in order to grasp the measured values ​​of each battery stack without delay. Furthermore, it is preferable for the wireless communication system 10 to be able to quickly recover from the stopped state when the operation of the slave-side communication software / hardware is stopped. Accordingly, when the vehicle is running, it is preferable for the slave-side application to instruct to switch to a standby state when the slave-side communication software / hardware becomes capable of stopping operation.

[0095] On the other hand, if the application system is a battery monitoring system, when the vehicle is stopped or parked, the changes in the state of each battery stack are small, so there is little need to acquire battery information as frequently as when the vehicle is running. For this reason, it is preferable for the application system to have a longer system cycle than when the vehicle is running. Also, when the wireless communication system 10 stops the operation of the slave-side communication software / hardware, it is preferable to obtain a greater power reduction effect by stopping the operation. Accordingly, when the vehicle is stopped or parked, it is preferable for the slave-side application to instruct the slave-side application to transition to a sleep state or deep sleep state when the slave-side communication software / hardware becomes capable of stopping its operation.

[0096] Furthermore, if the application system is a tire pressure monitoring system, the air pressure of the monitored tires affects the tire's driving condition when the vehicle is in motion. Therefore, when the vehicle is in motion, it is preferable for the application system to shorten its system cycle. Also, it is preferable for the wireless communication system 10 to be able to quickly recover from a stopped state if the communication software / hardware on the slave side stops operating. Accordingly, when the vehicle is in motion, it is preferable for the slave application to instruct the system to switch to a standby state when the communication software / hardware on the slave side becomes able to stop operating.

[0097] On the other hand, if the application system is a tire pressure monitoring system, there is little need to frequently acquire tire pressure when the vehicle is parked or stopped, since the tires do not rotate. Therefore, it is preferable for the application system to have a longer system cycle than when the vehicle is in motion. Furthermore, it is preferable for the wireless communication system 10 to obtain a greater power reduction effect when the communication software / hardware on the slave side stops operating. Accordingly, when the vehicle is parked or stopped, it is preferable for the slave application to be instructed to transition to a sleep state or deep sleep state when the communication software / hardware on the slave side becomes capable of stopping operation.

[0098] Furthermore, if the application system is a smart entry system, it is preferable for the master device 20 of the wireless communication system 10 to communicate with the smart key more frequently in order to detect with high accuracy the distance to the smart key when a user carrying the smart key approaches the vehicle while the vehicle is parked. For this reason, when the vehicle is parked and a user carrying the smart key approaches the vehicle, it is preferable for the application system to shorten the system cycle. Also, it is preferable for the wireless communication system 10 to be able to quickly recover from a stopped state if the communication software / hardware on the slave side stops operating. Accordingly, when the vehicle is parked and a user carrying the smart key approaches the vehicle, it is preferable for the slave application to instruct to switch to a standby state when the communication software / hardware on the slave side becomes able to stop operating.

[0099] On the other hand, if the application system is a smart entry system, once the vehicle starts moving, the smart key is inside the vehicle, so there is little need to communicate with the smart key frequently. Therefore, it is preferable for the application system to have a longer system cycle than when the vehicle is parked. Furthermore, when the wireless communication system 10 stops the operation of the slave-side communication software / hardware, it is preferable to achieve a greater power reduction effect by stopping that operation. Accordingly, after the vehicle starts moving, it is preferable for the slave-side application to be instructed to transition to a sleep state or deep sleep state when the slave-side communication software / hardware becomes capable of stopping its operation.

[0100] (Experimental variation 6) In Modification 5, the length of the system cycle was changed or the state (standby state or sleep state) of the slave-side communication software / hardware when it became possible to stop operation was changed depending on the state of the vehicle, including at least when it was in motion and when it was parked. Furthermore, the wireless communication system 10 may change the number of wireless communications performed within the system cycle depending on the state of the vehicle, including at least when it was in motion and when it was parked. For example, when the application system shortens the system cycle, it is preferable to change the number of wireless communications performed within the system cycle so that the number of wireless communications performed within the system cycle is greater than the number of wireless communications performed within the system cycle when the application system lengthens the system cycle. Generally, when the system cycle is shortened, a greater level of data reliability is required.

[0101] The features described in the above-described embodiments and each of the modified examples can be implemented in combination with the features described in other embodiments and each of the modified examples, except in cases where it is technically impossible to combine them.

[0102] Furthermore, for example, the devices, systems, and methods described in this disclosure may be implemented by a dedicated computer comprising a processor programmed to perform one or more functions embodied by a computer program. The devices and methods described in this disclosure may also be implemented using dedicated hardware logic circuits. The devices and methods described in this disclosure may also be implemented by one or more dedicated computers comprising a combination of a processor that executes a computer program and one or more hardware logic circuits. The processor may be any arithmetic core, such as a CPU, MPU, GPU, or DFP (Data Flow Processor). Some or all of the functions of the processor may be implemented by hardware. For example, some or all of the functions of the processor may be implemented using a system-on-a-chip (SoC), integrated circuit (IC), or field-programmable gate array (FPGA).

[0103] (Disclosure of technical ideas) Finally, this specification discloses several technical concepts described in the following sections. Some sections may be written in a polynomial form, selectively referencing several preceding sections. Furthermore, some sections may be written in a multiple polynomial form, referencing several sections, including other sections in a polynomial form. These sections written in polynomial and multiple polynomial forms define several technical concepts. Furthermore, the several technical concepts described in the following sections also apply to methods for controlling wireless communication systems.

[0104] (Technical thought 1) A wireless communication system used to acquire data required by a specified application system, At least one master node (20), It includes at least one slave node (30A, 30B, 40A, 40B, 50A), The master node and the slave node perform bidirectional wireless communication. The aforementioned data is transmitted from the slave node to the master node. The application system is required to acquire the latest value of the data at predetermined system cycles. The master node and the slave node are configured to communicate wirelessly multiple times within the system cycle. The master node transmits success information to the slave node when the application system successfully acquires the data during a predetermined number of wireless communications. A wireless communication system in which the slave node stops the remaining wireless communications of multiple wireless communications upon receiving the success information.

[0105] (Technical thought 2) The wireless communication system according to Technical Concept 1, wherein the master node and the slave node are configured to perform wireless communication three or more times within the system cycle.

[0106] (Technical Thought 3) The aforementioned slave node operates using power supplied from a battery, in the wireless communication system according to technical concept 1 or 2.

[0107] (Technical Thought 4) The master node has a calculation unit (S530, S540) that calculates the number of wireless communication attempts or the duration for which wireless communication can be stopped in the slave node. The master node transmits to the slave node, along with the success information, the number of times wireless communication can be stopped or the duration for which wireless communication can be stopped. The wireless communication system according to any one of Technical Ideas 1 to 3, wherein the slave node stops the wireless communication according to the number of received wireless communications or the duration for which the wireless communication can be stopped.

[0108] (Technical Thought 5) The wireless communication system according to technical concept 4, wherein the calculation unit counts the number of wireless communications performed between the master node and the slave node, and calculates the number of wireless communications that can be stopped or the amount of time that can be stopped based on the counted number of wireless communications.

[0109] (Technical Thought 6) The wireless communication system according to any one of Technical Concepts 1 to 5, wherein when the slave node stops wireless communication, it enters one of a plurality of low-power consumption states with different power consumption based on the number of wireless communication sessions or the duration for which wireless communication can be stopped.

[0110] (Technical Thought 7) The wireless communication system according to technical concept 6, wherein the more times wireless communication can be stopped, or the longer the time for which wireless communication can be stopped, the lower the power consumption of the slave node becomes.

[0111] (Technical Thought 8) The wireless communication system according to any one of technical ideas 1 to 7, wherein the master node is kept in a state where it can perform wireless communication with the slave node even when the slave node has stopped wireless communication.

[0112] (Technical Thought 9) The wireless communication system according to technical concept 8, wherein if an abnormality occurs that should be notified to the master node while the slave node has stopped wireless communication, the slave node resumes wireless communication and notifies the master node of the occurrence of the abnormality.

[0113] (Technical Thought 10) The aforementioned application system is a wireless communication system according to any one of the technical concepts 1 to 9, which is mounted on a vehicle.

[0114] (Technical Thought 11) The wireless communication system according to technical concept 10, wherein when the slave node stops wireless communication, it enters one of a plurality of low-power consumption states with different power consumption depending on the state of the vehicle, including at least while driving and while parked.

[0115] (Technical Thought 12) A wireless communication system according to technical concept 10 or 11, wherein the length of the system cycle varies depending on the state of the vehicle, including at least while driving and while parked.

[0116] (Technical Thought 13) A wireless communication system according to any one of technical ideas 10 to 12, wherein the number of wireless communications performed within the system cycle varies depending on the state of the vehicle, including at least while driving and while parked.

[0117] (Technical Thought 14) The vehicle is equipped with multiple application systems, A wireless communication system according to any one of the technical ideas 10 to 13, wherein the length of the system cycle and at least one of the number of wireless communications within the system cycle differ in a plurality of application systems.

[0118] (Technical Thought 15) An application system requiring high reliability for the aforementioned data is a wireless communication system according to technical concept 14, wherein the system cycle length is shorter and / or the number of wireless communication transmissions within the system cycle is greater compared to an application system where low reliability is sufficient.

[0119] (Technical Thought 16) A wireless communication system according to any one of Technical Ideas 1 to 15, wherein the master node and the slave node perform bidirectional wireless communication using encrypted packets. [Explanation of Symbols]

[0120] 1: Control device for the first application, 2: Control device for the second application, 3: Control device for the third application, 10: Wireless communication system, 20: Master device, 21: Control circuit, 22: Wireless communication circuit, 23: Antenna, 30A, 30B: Slave device for the first application, 31: Control circuit, 32: Wireless communication circuit, 33: Antenna, 35A, 35B: Equipment for the first application, 40A, 40B: Slave device for the second application, 45A: Equipment for the second application, 50A: Slave device for the third application, 55A: Equipment for the third application, 100: In-vehicle system

Claims

1. A wireless communication system used to acquire data required by a specified application system, At least one master node (20), It comprises at least one slave node (30A, 30B, 40A, 40B, 50A), The master node and the slave node perform bidirectional wireless communication. The aforementioned data is transmitted from the slave node to the master node. The application system is required to acquire the latest value of the data at predetermined system cycles. The master node and the slave node are configured to communicate wirelessly multiple times within the system cycle. The master node transmits success information to the slave node when the application system successfully acquires the data during a predetermined number of wireless communications. A wireless communication system in which the slave node stops the remaining wireless communications of multiple wireless communications upon receiving the success information.

2. The wireless communication system according to claim 1, wherein the master node and the slave node are configured to perform wireless communication three or more times within the system cycle.

3. The wireless communication system according to claim 1 or 2, wherein the slave node operates using power supplied from a battery.

4. The master node has a calculation unit (S530, S540) that calculates the number of wireless communication attempts or the duration for which wireless communication can be stopped in the slave node. The master node transmits to the slave node, along with the success information, the number of times wireless communication can be stopped or the duration for which wireless communication can be stopped. The wireless communication system according to claim 1 or 2, wherein the slave node stops the wireless communication according to the number of received wireless communications or the duration for which the wireless communication can be stopped.

5. The wireless communication system according to claim 4, wherein the calculation unit counts the number of wireless communications performed between the master node and the slave node, and calculates the number of wireless communications that can be stopped or the amount of time that can be stopped based on the counted number of wireless communications.

6. The wireless communication system according to claim 1 or 2, wherein when the slave node stops wireless communication, it enters one of a plurality of low-power consumption states with different power consumption based on the number of wireless communication sessions or the duration for which wireless communication can be stopped.

7. The wireless communication system according to claim 6, wherein the more times wireless communication can be stopped, or the longer the time for which wireless communication can be stopped, the lower the power consumption of the slave node becomes.

8. The wireless communication system according to claim 1 or 2, wherein the master node is kept in a state where it can perform wireless communication with the slave node even when the slave node has stopped wireless communication.

9. The wireless communication system according to claim 8, wherein if an abnormality occurs that should be notified to the master node while the slave node has stopped wireless communication, the slave node resumes wireless communication and notifies the master node of the occurrence of the abnormality.

10. The application system is a wireless communication system according to claim 1 or 2, mounted on a vehicle.

11. The wireless communication system according to claim 10, wherein when the slave node stops wireless communication, it enters one of a plurality of low-power consumption states with different power consumption depending on the state of the vehicle, including at least while driving and while parked.

12. The wireless communication system according to claim 10, wherein the length of the system cycle changes according to the state of the vehicle, including at least while driving and while parked.

13. The wireless communication system according to claim 10, wherein the number of wireless communications performed within the system cycle varies depending on the state of the vehicle, including at least while driving and while parked.

14. The vehicle is equipped with multiple application systems, The wireless communication system according to claim 10, wherein at least one of the length of the system cycle and the number of wireless communications within the system cycle differs among the multiple application systems.

15. The wireless communication system according to claim 14, wherein the application system requiring high reliability of the data has a shorter system cycle length and / or a larger number of wireless communication operations within the system cycle compared to the application system where low reliability is sufficient.

16. The wireless communication system according to claim 1 or 2, wherein the master node and the slave node perform bidirectional wireless communication using encrypted packets.

17. A control method for a wireless communication system used to acquire data required by a predetermined application system, The wireless communication system comprises at least one master node (20) and at least one slave node (30A, 30B, 40A, 40B, 50A), The master node and the slave node perform bidirectional wireless communication. The aforementioned data is transmitted from the slave node to the master node. The application system is required to acquire the latest value of the data at predetermined system cycles. The master node and the slave node are configured to communicate wirelessly multiple times within the system cycle. The master node transmits success information to the slave node when the application system successfully acquires the data in a predetermined number of wireless communications, and A control method for a wireless communication system, comprising: the slave node stopping the remaining wireless communication of multiple wireless communications in response to the receipt of the success information.

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