Mobile station, time synchronization control device, cooperative operation control device, communication system, synchronization control method, control circuit, and storage medium

Abstract

The mobile station (13) includes a plurality of mobile stations capable of terminal-to-terminal communication, and in a network that realizes time-synchronized communication, the mobile station (13) operates as a master mobile station that transmits, by terminal-to-terminal communication, control information generated by a cooperative operation control device that controls a controlled device taking into account a transmission delay time in an information transmission path between the controlled device and the mobile station, and is provided with a scheduler unit (132) that determines and changes radio resources to be used in terminal-to-terminal communication with a remote mobile station that is a mobile station to which the controlled device, the destination of the control information, is connected, and a time synchronization unit (131) that checks whether the time position of the radio resource has changed when the scheduler unit changes the radio resource, and, if the time position has changed, notifies the time synchronization control unit (11) that calculates the transmission delay time of the amount of change in the time position.

Description

[Technical field]

[0001] The present disclosure relates to a mobile station, a time synchronization control device, a linkage operation control device, a communication system, a synchronization control method, a control circuit, and a storage medium that constitute a communication system that performs time-synchronized communication. [Background technology]

[0002] In recent years, systems have been developed that connect multiple industrial devices to a network and operate them in cooperation. Such systems are used in a wide range of applications. For example, a system has been put into practical use in which multiple robot arms are connected to a network in a factory production line, and they perform manufacturing in cooperation with time synchronization based on commands from a specific control device. There are many options for such networks, and multiple standards are provided under names such as fieldbus and industrial Ethernet (registered trademark). By connecting multiple devices to a network, it becomes possible to respond to emergencies and share sensor information, making it possible to build a safe and efficient system. Fieldbuses, industrial Ethernets, and the like require strict time synchronization between devices, so they are designed to minimize delays in signal transmission, and a standard called TSN (Time Sensitive Networking) that performs time synchronization is widely used.

[0003] Meanwhile, development of time-synchronized communication using wireless communication technology, known as TSC (Time Sensitive Communication), has begun to accommodate small-lot, high-mix production and to incorporate not only production lines but also moving objects such as AGVs (Automatic Guided Vehicles) into networks. One example is the 5GS (Fifth Generation System), which is being considered by 3GPP (Third Generation Partnership Project), which is standardizing mobile communication systems.

[0004] For example, Patent Document 1 discloses a technology for a TSC network that is composed of a core device, a base station that is a wireless access device, a mobile station that is a terminal device, a TSN translator, etc. Figure 2 of Patent Document 1 shows a configuration in which an End Station that is a network component device on a TSN working domain outside the core device and an End Station connected to a terminal device are connected via 5GS, and time-synchronized communication is performed between the two devices. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2021 / 059538 Summary of the Invention [Problem to be solved by the invention]

[0006] When connecting synchronously operating End Stations with 5GS and other wired networks, the 5GS providing the time synchronization service operates as a virtual TSN bridge from the perspective of the End Station. The virtual TSN bridge played by 5GS is expected to keep the delay time constant by providing a buffer that can hold data signals, such as a TSN translator.

[0007] Generally speaking, the scheduler function unit in a base station belonging to 5GS allocates the radio resources necessary for information transmission so that the propagation delay between the nodes that make up the virtual TSN is as constant as possible.

[0008] As one of the functions of a mobile communication system, a function for terminal devices to communicate directly with each other without going through a base station (hereinafter, sometimes referred to as terminal-to-terminal communication) has been standardized by 3GPP, and it is possible to apply this function to the above-mentioned synchronous operation. That is, there may be a case where a section in which terminal devices communicate directly with each other is included in a path for transmitting information for realizing synchronous operation to multiple end stations that operate synchronously. However, the allocation of radio resources used in terminal-to-terminal communication is usually performed between terminal devices, and the scheduler function unit in the base station is not involved. For this reason, it is difficult for the scheduler function unit in the base station to control the propagation delay between nodes that make up the virtual TSN to be as constant as possible.

[0009] The present disclosure has been made in consideration of the above, and aims to obtain a mobile station capable of achieving synchronous control of multiple devices connected via a network that includes sections in which terminal devices communicate directly with each other. [Means for solving the problem]

[0010] In order to solve the above-mentioned problems and achieve the object, the present disclosure is characterized in that in a network that includes a plurality of mobile stations capable of terminal-to-terminal communication and realizes time-synchronized communication, a mobile station operates as a master mobile station that transmits control information generated by a collaborative operation control device that controls a controlled device by taking into account a transmission delay time in an information transmission path between the controlled device, and is equipped with a scheduler unit that determines and changes radio resources to be used in terminal-to-terminal communication with a remote mobile station that is a mobile station to which the controlled device to which the control information is to be transmitted is connected, and a time synchronization unit that checks whether the time position of the radio resource has changed when the scheduler unit changes the radio resource, and if the time position has changed, notifies a time synchronization control unit that calculates the transmission delay time of the amount of change in the time position. Effect of the Invention

[0011] A mobile station according to the present disclosure has an effect of enabling synchronization control of a plurality of devices connected via a network that includes a section in which terminal devices communicate directly with each other. [Brief description of the drawings]

[0012] [Figure 1] A diagram showing information used for packet control in time-synchronized communication. [Diagram 2] FIG. 1 is a diagram illustrating an example of a use case of a communication system according to a first embodiment. [Diagram 3] FIG. 1 shows an example of a network configuration assumed in a first embodiment. [Figure 4] FIG. 1 is a diagram showing a configuration example of a communication system according to a first embodiment; [Diagram 5] A diagram showing an example of a frame format used when a mobile station communicates with another mobile station in 5GS [Figure 6] FIG. 1 is a diagram illustrating an example of a transmission operation of control information in the communication system according to the first embodiment; [Figure 7] FIG. 1 is a diagram illustrating a first operation example of the communication system according to the first embodiment. [Figure 8] FIG. 11 is a diagram illustrating a second operation example of the communication system according to the first embodiment. [Figure 9] 1 is a flowchart showing an example of an operation of the communication system according to the first embodiment. [Figure 10] FIG. 1 is a diagram illustrating an example of a processing circuit for implementing a mobile station constituting a communication system according to a first embodiment, in the case where the processing circuit is implemented by a processor and a memory. [Figure 11] FIG. 1 is a diagram illustrating an example of a processing circuit for implementing a mobile station in a communication system according to a first embodiment, the processing circuit being configured with dedicated hardware; [Figure 12] FIG. 1 is a diagram illustrating a configuration example of a communication system according to a second embodiment. [Figure 13] FIG. 11 is a diagram illustrating an example of a transmission operation of sensor information in the communication system according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A mobile station, a time synchronization control device, a cooperation operation control device, a communication system, a synchronization control method, a control circuit, and a storage medium according to embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0014] Embodiment 1 First, as a comparative example, a method for achieving synchronous control via a network that does not include a section in which terminal devices communicate directly with each other will be described.

[0015] As described above, in 5GS that provides time synchronization services, the scheduler function unit in the base station allocates radio resources so that the propagation delay between nodes is as constant as possible. However, due to the influence of the frequency offset between the grandmaster clock on the TSN working domain to which the End Station belongs and the clock source that the 5GS has independently, and the traffic conditions of other users to which the 5GS simultaneously provides services, there is a problem that the propagation delay does not match, such as the arrival timing of the information packet from the End Station and the allocation timing of the radio resource not matching. To solve this problem, a mechanism for adjusting the timing error has also been introduced. For example, in Table 5.27.2-1 of 3GPP TS23.501 V17.2.0 (2021-09), TSCAI (Time Sensitive Communication Assistance Information) shown in Figure 1 is specified as information for controlling TSC packets. In the comparative example system that realizes the time synchronization service, the transmission delay time is shortened by specifying the period of the information packet transmitted by the End Station and the arrival timing to the 5GS in TSCAI. A part of the information of the TSCAI is passed from the AMF (Access and Mobility Management Function), which is a part of the core function, to the (R)AN and the UE (User Equipment), and is used for radio transmission scheduling. An example of using the TSCAI for (R)AN scheduling is also disclosed in paragraph 0058 of the above-mentioned Patent Document 1. The UE is also called a terminal device or a mobile station.

[0016] The above-mentioned method of reducing latency using TSCAI requires the existence of the 5GS core function unit, and therefore cannot be applied to systems that include sections where terminal devices communicate directly with each other. Therefore, it is desirable to realize a method that does not require the 5GS core function unit.

[0017] Next, a communication system according to the present embodiment will be described. FIG. 2 is a diagram showing an example of a use case of the communication system according to the first embodiment. FIG. 2 shows an example of a cooperative transport device that transports one piece of luggage 150 with a plurality of driving devices. In this use case, each end station under four UEs is connected to a motor constituting a driving device and controls the moving speed and direction. In this case, in order to transport the luggage 150 well, the speed and direction must be precisely matched among the four driving devices, and communication with lower latency is required. In other words, in an application such as servo control that is conventionally directly connected by wire and controlled with a fixed delay time, the wiring is replaced with a wireless line. In this embodiment, the wireless line to replace the wiring is realized by terminal-to-terminal communication.

[0018] FIG. 3 is a diagram showing an example of the configuration of a network assumed in the first embodiment. The network assumed in this embodiment is composed of a plurality of UEs and a direct communication path between the UEs, which is a section where terminal-to-terminal communication is performed. This network is called a local UE-to-UE wireless TSC network. For example, in the use case shown in FIG. 2 above, one of the UEs becomes a master mobile station (Master UE) and transmits control information to the master mobile station (Master UE) and other remote mobile stations (Remote UE) that are under its control (sometimes called controlled devices) 301-303, 311-313, 321-323, thereby realizing a desired operation in the entire TSC network. In 3GPP, a link for terminal-to-terminal communication is called a SideLink (SL). In FIG. 3, a two-way arrow labeled "SL" indicates a link for terminal-to-terminal communication.

[0019] Fig. 4 is a diagram showing a configuration example of a communication system 100 according to the first embodiment. Note that a mobile station is denoted as "UE" in Fig. 4. This also applies to the drawings used in the following description.

[0020] The communication system 100 according to this embodiment includes one master mobile station 13 and multiple remote mobile stations 23 (remote mobile stations 23-1 and 23-2 are shown in FIG. 4). A network consisting of the master mobile station 13 and the multiple remote mobile stations 23 realizes time-synchronized communication. The master mobile station 13 and the remote mobile station 23 have an inter-terminal communication function and can directly communicate with other mobile stations without going through a base station. In the communication system 100, the master mobile station 13 directly communicates with each of the remote mobile stations 23-1 and 23-2.

[0021] An application control unit 10 that controls applications to be realized by a time synchronization network, which is a network formed by the master mobile station 13 and the remote mobile stations 23-1 and 23-2, is connected to the master mobile station 13 via a DS-TT (Device Side Tsn Translator) 12. DS-TT is specified in the above-mentioned document "3GPP TS23.501 V17.2.0 (2021-09)" and performs processing for realizing a time synchronization function. In addition, a controlled device 15 that can be controlled without a wireless line is connected to the application control unit 10.

[0022] The master mobile station 13 includes a time synchronization unit 131 that controls the TSC function as a mobile station, a scheduler unit 132 that determines radio resources to be used in terminal-to-terminal communication, and a radio function unit 133 that performs transmission and reception processing of radio signals. A grandmaster clock (GM) 14 that provides a reference clock for this time synchronization network is connected to the master mobile station 13. The reference clock does not necessarily need to be an independent functional block, and time information reproduced by a GPS receiver or time information generated by an oscillator built into the mobile station may be used.

[0023] In addition, between the master mobile station 13 and the application control unit 10, a time synchronization control unit 11 that controls the TSC function of the entire system including the master mobile station 13 and the multiple remote mobile stations 23 is provided.

[0024] The remote mobile stations 23-1 and 23-2 have the same configuration as the master mobile station 13, but different reference numerals are used for corresponding components in Fig. 4. The remote mobile stations 23-1 and 23-2 each include a time synchronization unit 231 having a function similar to that of the time synchronization unit 131 of the master mobile station 13, a scheduler unit 232 having a function similar to that of the scheduler unit 132 of the master mobile station 13, and a wireless function unit 233 having a function similar to that of the wireless function unit 133 of the master mobile station 13. The remote mobile station 23 is connected to the controlled device 25 via a DS-TT 22 that performs the same process as the above-mentioned DS-TT 12. In 3GPP, a wireless interface on SL is called PC5.

[0025] The application control unit 10 and the time synchronization control unit 11 are provided in, for example, a control device that controls the operations of the controlled devices 15 and 25 .

[0026] Although FIG. 4 shows an example in which a controlled device is not connected to master mobile station 13, a configuration in which a controlled device is connected to master mobile station 13 may be used, similar to the example shown in FIG.

[0027] Next, the operation of the communication system 100 according to the first embodiment will be described. The application control unit 10 generates control information for operating a desired application. As an example, the cooperative transport device shown in FIG. 2 is taken up. In this example, the application control unit 10 generates control information such as speed, direction, and torque for the controlled device 15 under its control and the controlled device 25 under each of the multiple remote mobile stations 23. This control information can be expressed in various ways, and for example, it is possible to notify angle information of each motor at a specific time, and the content of the control information is not limited. In this embodiment, the purpose is to fix the delay time of the control information, which is the time required from when the application control unit 10 outputs the control information until the control information arrives at the controlled devices 15 and 25. For this reason, the application control unit 10 generates and outputs the control information taking into account the delay time of the control information. In order to transmit this control information from the application control unit 10 to the controlled device 25 under the remote mobile station 23, a specific communication session is set, radio resources are allocated, and the control information is transmitted.

[0028] Fig. 5 is a diagram showing an example of a frame format used when a mobile station performs terminal-to-terminal communication in 5GS. A part of UL (UpLink) resources reserved for transmission from a mobile station to a base station in communication between the mobile station and the base station is allocated to the SL. Resources that can be allocated to the SL are an area designated by a time and frequency range called the SL Resource Pool. This area may be arranged quite discretely in terms of time.

[0029] Fig. 6 is a diagram showing an example of a control information transmission operation in the communication system 100 according to the first embodiment. Fig. 6 shows an example of transmitting control information from the application control unit 10 to the controlled device 25 under the remote mobile station 23 at a control period of 5 ms. The vertically long rectangles in the upper row indicate resources for wireless communication. "U" indicates UL resources and "D" indicates DL (DownLink) resources. Also, "●" indicates resources allocated for terminal-to-terminal communication.

[0030] For applications that perform periodic control as shown in FIG. 6, resource allocation called semi-persistent scheduling is performed. The scheduler unit 132 of the master mobile station 13 continuously secures radio resources at 5 ms intervals as shown in FIG. 6. Specifically, the application control unit 10 issues an information transmission request at 5 ms intervals to the time synchronization control unit 11, and the time synchronization control unit 11 instructs the time synchronization unit 131 of the master mobile station 13 to secure resources at 5 ms intervals for terminal-to-terminal communication with the remote mobile station 23. The time synchronization unit 131 instructs the scheduler unit 132 to secure appropriate resources, taking into consideration conflicts with communication resources used in other sessions. In FIG. 6, the master DS-TT corresponds to the DS-TT 12 shown in FIG. 4, and the remote DS-TT corresponds to the DS-TT 22 shown in FIG. 4.

[0031] In the case of the control information transmission operation of the example shown in FIG. 6, the application control unit 10 generates control information at time Ts and transmits the control information to the controlled device 25 via the master DS-TT (DS-TT 12), the master UE (master mobile station 13), the remote UE (remote mobile station 23), and the remote DS-TT (DS-TT 22). Note that the time Ts is assumed to be a relative time from the head timing of the 5GS radio frame or a relative time from any timing corresponding to the 5GS radio frame, but may be an absolute time outside the 5GS such as Universal Time. If the transmission delay time in the 5GS is Td1, the application control unit generates and transmits control information for the controlled device 25 at time Ts+Td1 at time Ts. In the example shown in FIG. 6, the next information transmission timing is Ts+5 ms. Since the transmission delay time Td1 in the 5GS is different for each session, the application control unit 10 generates and transmits control information at different timing for each session. When multiple controlled devices 25 exist under one remote mobile station 23, multiple sessions may be established between the master mobile station 13 and the remote mobile station 23. In this case, even if the controlled devices 25 are under the same remote mobile station 23, the control information is generated and transmitted at different timings for each controlled device 25.

[0032] Here, according to the 5GS standard, it is mandatory to periodically change the position where the SL resource is reserved for the terminal-to-terminal communication for a specific session. This is an operation called "resource reselection". When the radio resource can be reserved at a different frequency position in the slot of the same timing at the time of resource reselection, there is no problem, but the radio resource may be reserved in a different slot. FIG. 7 is a diagram showing a first operation example of the communication system 100 according to the first embodiment. FIG. 7 shows a transmission operation of control information when resource reselection is performed in the terminal-to-terminal communication. FIG. 7 shows an operation example when a slot of a different timing than before is reserved in the resource reselection, specifically, an operation example when the position of the reserved radio resource is shifted 2 slots behind. In this example, the timing of the radio resource reserved for the control information transmission is delayed by 1 ms relative to the transmission timing of the application control. The delay time fluctuation is absorbed to some extent by the buffering of the DS-TT22, but when the buffer amount is reduced to reduce the delay, the transmission delay time in the 5GS is changed from Td1 to Td2. This leads to discrepancies in the control information.

[0033] A process for preventing such a problem from occurring is performed in the communication system 100 according to the present embodiment. Specifically, in the communication system 100, the time synchronization unit 131 detects a change in the time position of the radio resource due to resource reselection, and notifies the time synchronization control unit 11 of the difference, i.e., the amount of change, as, for example, a BAT (Burst Arrival Time) offset. The time synchronization control unit 11 calculates a new transmission delay time Td2 within 5GS based on the offset information, which is the BAT offset notified from the time synchronization unit 131, and notifies the application control unit 10 of all or part of the information on the current BAT (=Ts), the transmission delay time within 5GS, and the BAT offset. The calculation of the transmission delay time Td2 may be performed by the time synchronization unit 131. In this case, the new transmission delay time Td2 is notified to the time synchronization control unit 11 from the time synchronization unit 131 together with the BAT offset.

[0034] When the application control unit 10 receives a notification of the information from the time synchronization control unit 11 that has calculated the new transmission delay time Td2 within 5GS, the application control unit 10 implements one of the following two types of countermeasure methods.

[0035] The first countermeasure is to change the assumed transmission delay time within the 5GS. In the example shown in FIG. 7, this countermeasure is implemented. Specifically, when the time synchronization control unit 11 notifies the application control unit 10 of the BAT offset and the transmission delay time Td2, the application control unit 10 changes the transmission delay time in communication with the controlled device 25 under the remote mobile station 23 to Td2. That is, the application control unit 10 changes the transmission delay time to the controlled device 25 used when generating control information for the controlled device 25. After this, the application control unit 10 generates control information at the time Ts+Td2 and continues to control the system.

[0036] The second solution is to change Ts, which is the timing at which control information is transmitted from the application control unit 10 to the DS-TT 12. Naturally, it is preferable that the transmission delay time from the application control unit 10 to the controlled device 25 is short. This second solution will be described with reference to FIG. 8.

[0037] Fig. 8 is a diagram showing a second operation example of the communication system 100 according to the first embodiment. Fig. 8 shows a transmission operation of control information when resource reselection is performed in terminal-to-terminal communication, similar to Fig. 7. Fig. 8 shows an example in which the position of the radio resource secured in resource reselection is shifted two slots behind from the previous position, similar to Fig. 7.

[0038] If the transmission timing in the wireless line is delayed by 1 ms due to resource reselection, the application control unit 10 delays the BAT (=Ts) by 1 ms to minimize the transmission delay time. If the new transmission delay time in the 5GS is Td3, the application control unit 10 generates and transmits control information at the time point of Ts+Td3. Generally, Td1 and Td3 are considered to be close in length of time, but are not necessarily the same.

[0039] All of the functional units constituting the system, including the application control unit 10 and the time synchronization control unit 11, receive clock information synchronized with the GM 14 and are time-synchronized. This does not necessarily mean that they are driven by the same clock, but rather, they may be configured to achieve time synchronization by managing and correcting the frequency difference between the local clock and the GM clock. Clock information is distributed using PTP (Precision Time Protocol), ASTI (Access Stratum Timing Distribution System), etc.

[0040] Fig. 9 is a flowchart showing an example of the operation of the communication system 100 according to the embodiment 1. The flowchart in Fig. 9 shows the operation when resource reselection is executed in terminal-to-terminal communication.

[0041] In the communication system 100, first, the scheduler unit 132 of the master mobile station 13 executes resource reselection (step S11). Next, the time synchronization unit 131 checks whether or not the slot position has been changed, that is, whether or not the time position of the radio resource has been changed with the execution of resource reselection (step S12). If the slot position has not been changed (step S12: No), the operation ends. If the slot position has been changed (step S12: Yes), the application control unit 10 adjusts the transmission timing of the control information (step S13). In this step S13, the transmission timing is adjusted using the above-mentioned method of changing the transmission delay time Td assumed in 5GS (method shown in FIG. 7) or the method of changing the BAT (method shown in FIG. 8).

[0042] In this way, in the communication system 100 according to the present embodiment, when the master mobile station 13 performs resource reselection for terminal-to-terminal communication, it checks whether or not there has been a change in the slot position, and when there has been a change, it performs a change in the transmission delay time expected in 5GS or a change in the BAT. This makes it possible to realize synchronous control of a plurality of controlled devices even if the slot position has changed due to resource reselection for terminal-to-terminal communication in a network having a configuration including a section to which terminal-to-terminal communication is applied.

[0043] The application control unit 10 and the time synchronization control unit 11 may be provided in one device that controls a plurality of controlled devices using time-synchronized communication, or may be provided in different devices. For example, the application control unit 10 may be provided in the cooperation control device, and the time synchronization control unit 11 may be provided in the time synchronization control device. Also, the time synchronization unit 131 of the master mobile station 13 may be configured to have the functions of the time synchronization control unit 11, that is, the time synchronization unit 131 may also operate as the time synchronization control unit 11.

[0044] Next, the hardware configuration of each device in the communication system 100 will be described. The wireless function unit 133 of the master mobile station 13 and the wireless function unit 233 of the remote mobile stations 23-1 and 23-2 are realized by, for example, a transceiver. The time synchronization unit 131 and the scheduler unit 132 of the master mobile station 13 and the time synchronization unit 231 and the scheduler unit 232 of the remote mobile stations 23-1 and 23-2 are realized by a processing circuit. The processing circuit may be a processor and memory that executes a program stored in a memory, or may be dedicated hardware. The processing circuit is also called a control circuit.

[0045] FIG. 10 is a diagram showing an example of a processing circuit 90 in the case where a processing circuit for realizing a mobile station (master mobile station 13, remote mobile stations 23-1, 23-2) constituting the communication system 100 according to the first embodiment is realized by a processor 91 and a memory 92. The processing circuit 90 shown in FIG. 10 includes a processor 91 and a memory 92. Each function of the processing circuit 90 is realized by software, firmware, or a combination of software and firmware. The software or firmware is described as a program and stored in the memory 92. In the processing circuit 90, each function is realized by the processor 91 reading and executing the program stored in the memory 92. That is, the processing circuit 90 includes a memory 92 for storing a program that results in the processing of the mobile station constituting the communication system 100 being executed. This program can also be said to be a program for causing the mobile station to execute each function realized by the processing circuit 90. This program may be provided by a storage medium in which the program is stored, or may be provided by other means such as a communication medium.

[0046] The processor 91 is, for example, a central processing unit (CPU), a processing device, an arithmetic unit, a microprocessor, a microcomputer, or a digital signal processor (DSP). The memory 92 is, for example, a non-volatile or volatile semiconductor memory such as a random access memory (RAM), a read only memory (ROM), a flash memory, an erasable programmable ROM (EPROM), or an electrically EPROM (EEPROM (registered trademark)).

[0047] Fig. 11 is a diagram showing an example of a processing circuit 93 in the case where the processing circuit for implementing the mobile station constituting the communication system 100 according to the first embodiment is implemented by dedicated hardware. The processing circuit 93 shown in Fig. 11 corresponds to, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination of these. The processing circuit may be partially implemented by dedicated hardware and partially implemented by software or firmware. In this way, the processing circuit can implement each of the above-mentioned functions by dedicated hardware, software, firmware, or a combination of these.

[0048] Embodiment 2 In a control application as shown in Fig. 2, it is generally necessary not only to send control information one-way but also to obtain the state of the controlled device by a sensor and feed it back to the control device. Therefore, in this embodiment, a communication system that realizes feedback from the controlled device is disclosed.

[0049] Fig. 12 is a diagram showing a configuration example of a communication system 100a according to the second embodiment. In Fig. 12, components common to the communication system 100 according to the first embodiment shown in Fig. 4 are given the same reference numerals as those in the communication system 100. Descriptions of components given the same reference numerals as those in the communication system 100 are omitted.

[0050] The communication system 100a includes a master mobile station 13 and a plurality of remote mobile stations 23a (remote mobile stations 23a-1 and 23a-2 are illustrated in FIG. 12). The remote mobile station 23a includes a time synchronization unit 231a, a scheduler unit 232, and a wireless function unit 233. The communication system 100a also includes an application control unit 10a and a time synchronization control unit 11a.

[0051] A sensor 26 is attached to each of the controlled devices 25. Sensor information output by the sensor 26 is transmitted to the application control unit 10a via the DS-TT 22, the remote mobile station 23a, the master mobile station 13, and the DS-TT 12.

[0052] Next, a description will be given of the operation of the communication system 100a according to the embodiment 2. The operation of transmitting control information from the master mobile station 13 to the remote mobile station 23a in the communication system 100a is similar to that in the communication system 100 according to the embodiment 1, and therefore the description will be omitted.

[0053] The sensor 26 is responsible for measuring the state of the controlled device 25 and notifying the application control unit 10a. If the sensor 26 is a high-performance sensor, a timestamp of the measurement time is added to the measurement information to create sensor information, and the sensor information is transmitted. In this case, the application control unit 10a can adjust the processing timing, etc., based on the timestamp included in the sensor information. On the other hand, in the conventional sensors, all the information transmission paths are connected by wire, and many of them are processed on the premise of a fixed delay time. In addition, it is assumed that a new timestamp cannot be added due to the relationship of the transmission format. For this reason, in this embodiment, a communication system 100a that does not require a timestamp, that is, a communication system 100a that enables information transmitted from the sensor 26 to the application control unit 10a to be used for synchronous control of the controlled device 25 without using a timestamp, is described.

[0054] Fig. 13 is a diagram showing an example of a transmission operation of sensor information in the communication system 100a according to the second embodiment. Fig. 13 shows an example of the timing when information is transmitted from the sensor 26 to the application control unit 10a. It is assumed that the sensor 26 generates information every 5 ms.

[0055] In the example shown in FIG. 13, sensor information occurs at a relative time Ts from some reference timing of a radio frame, and the information is transmitted to the application control unit 10a via the DS-TT 22, the remote mobile station 23a, the master mobile station 13, and the DS-TT 12. The arrival time of the sensor information at the application control unit 10a is the time obtained by adding the assumed transmission delay time within 5GS to the relative time Ts of the sensor information. In this case, if the transmission delay time within 5GS is Td4, the application control unit 10a can recognize that the received sensor information is from the time Ts based on the information on the transmission delay time Td4 provided by the time synchronization control unit 11a. If the radio resource secured by the remote mobile station 23a shifts backward by 2 slots (=1 ms) in the resource reselection, the time synchronization unit 231a detects the shift in slot position, and the difference is notified to the time synchronization control unit 11a as, for example, a BAT offset. The time synchronization control unit 11a calculates a new transmission delay time Td5 within 5GS from this information, and notifies the application control unit 10a of all or part of the information on the current BAT (=Ts), the transmission delay time within 5GS, and the BAT offset. The calculation of the transmission delay time Td5 may be performed by the time synchronization unit 231a. In this case, the new transmission delay time Td5 is notified to the time synchronization control unit 11a together with the BAT offset.

[0056] The application control unit 10a receives the transmission delay time Td5 from the time synchronization control unit 11a and calculates the time Ts when the sensor information was generated. That is, if the sensor information is passed from the DS-TT 12 to the application control unit 10a at time Tr, the application control unit 10a can estimate the time when the sensor information was generated by Ts = Tr - Td5. Note that the time synchronization control unit 11a may directly pass Ts to the application control unit 10a.

[0057] In general, it is desirable that the sensor information obtained by the application control unit 10a is as new as possible. That is, it is desirable to change the generation timing of the sensor information and minimize the BAT offset. For this reason, the application control unit 10a or the time synchronization control unit 11a notifies the sensor 26 of a new transmission timing (BAT) of the sensor information that can minimize the BAT offset. In the sensor 26, the transmission timing Ts from the sensor 26 is calculated and updated based on the BAT. The time synchronization control unit 11a calculates the 5GS delay time from the DS-TT22 to the DS-TT12 based on the new transmission timing Ts, and notifies the application control unit 10a. The application control unit 10a that receives this notification changes the 5GS delay time used in the generation process of the control information for the controlled device 25 to the 5GS delay time notified from the time synchronization control unit 11.

[0058] As described above, in the communication system 100a according to the present embodiment, the application control unit 10a acquires the transmission delay time expected in 5GS from the time synchronization control unit 11a, and calculates the time when the sensor information acquired from the sensor 26 connected to the remote mobile station 23a was transmitted based on the acquired transmission delay time. When the remote mobile station 23a performs resource reselection for terminal-to-terminal communication, it checks whether or not the slot position has been changed, and if there has been a change, the time synchronization control unit 11a changes the transmission delay time expected in 5GS, and the application control unit 10a uses the changed transmission delay time to calculate the time when the sensor information was transmitted. In addition, the time synchronization control unit 11a determines a new transmission timing of the sensor information and notifies the sensor 26 of the new transmission timing. The sensor 26 changes the transmission timing of the sensor information to the notified transmission timing. As a result, even if the slot position changes due to resource reselection for terminal-to-terminal communication in a network configuration including a section to which terminal-to-terminal communication is applied, the application control unit 10a can grasp the time at which the sensor information was transmitted from the remote mobile station 23a to the application control unit 10a, thereby realizing synchronous control of multiple controlled devices.

[0059] The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies, or the embodiments may be combined with each other. Also, parts of the configurations may be omitted or modified without departing from the spirit of the invention. [Explanation of symbols]

[0060] 10,10a application control unit, 11,11a time synchronization control unit, 12,22 DS-TT, 13 master mobile station, 14 grandmaster clock, 15,25 controlled device, 23-1,23-2,23a-1,23a-2 remote mobile station, 26 sensor, 100,100a communication system, 131,231,231a time synchronization unit, 132,232 scheduler unit, 133,233 wireless function unit, 150 luggage, 301 to 303, 311 to 313, 321 to 323 controlled device.

Claims

1. In a network including a plurality of mobile stations capable of terminal-to-terminal communication and realizing time-synchronized communication, a mobile station operates as a master mobile station that transmits control information generated by a cooperative operation control device that controls a controlled device by taking into account a transmission delay time in an information transmission path between the controlled device and the mobile station, a scheduler unit that determines and changes radio resources to be used in the terminal-to-terminal communication with a remote mobile station that is a mobile station to which the controlled device, which is a destination of the control information, is connected; a time synchronization unit that checks whether a time position of the wireless resource has been changed when the scheduler unit changes the wireless resource, and notifies a time synchronization control unit that calculates the transmission delay time of an amount of change in the time position when the time position has been changed; A mobile station comprising:

2. In a network including a plurality of mobile stations capable of terminal-to-terminal communication and realizing time-synchronized communication, a mobile station operates as a master mobile station that transmits control information generated by a cooperative operation control device that controls a controlled device by taking into account a transmission delay time in an information transmission path between the controlled device and the mobile station, a scheduler unit that determines and changes radio resources to be used in the terminal-to-terminal communication with a remote mobile station that is a mobile station to which the controlled device, which is a destination of the control information, is connected; a time synchronization unit that, when the scheduler unit changes the wireless resource, checks whether a time position of the wireless resource has been changed, and, if the time position has been changed, calculates the transmission delay time based on an amount of change in the time position and notifies the cooperative operation control device of the calculated transmission delay time; A mobile station comprising:

3. In a network including a plurality of mobile stations capable of terminal-to-terminal communication and realizing time-synchronized communication, a controlled device is connected to the network, and a mobile station that operates as a remote mobile station receives control information generated by a cooperative operation control device that controls the controlled device by taking into account a transmission delay time in an information transmission path between the controlled device and the mobile station, a scheduler unit that determines and changes radio resources to be used in the inter-terminal communication when transmitting information to the collaboration control device; a time synchronization unit that checks whether a time position of the wireless resource has been changed when the scheduler unit changes the wireless resource, and notifies a time synchronization control unit that calculates the transmission delay time of an amount of change in the time position when the time position has been changed; A mobile station comprising:

4. A time synchronization control device constituting a communication system together with the mobile station according to claim 1 and operating as the time synchronization control unit, when notified of the amount of change from the time synchronization unit, calculates the transmission delay time based on the amount of change, and notifies the calculated transmission delay time and the amount of change to the collaboration control device. A time synchronization control device comprising:

5. The cooperation control device constituting a communication system together with the mobile station according to claim 3, When the transmission delay time calculated based on the change amount is notified from the time synchronization control unit, the notified transmission delay time is changed so as to be used in the generation process of the control information. A cooperative operation control device comprising:

6. A communication system including a plurality of mobile stations capable of terminal-to-terminal communication, forming a network for realizing time-synchronized communication, a master mobile station which is the mobile station that transmits control information for controlling a controlled device through the inter-terminal communication; a plurality of remote mobile stations which are mobile stations to which the controlled device, which is a destination of the control information, is connected; an application control unit that generates the control information and transmits the control information to the controlled device via the master mobile station and the remote mobile station; a time synchronization control unit that calculates a transmission delay time when the control information is transmitted from the application control unit to the controlled device; Including, the master mobile station determines and changes a radio resource to be used in the terminal-to-terminal communication with the remote mobile station to which the controlled device to which the control information is to be transmitted is connected, and when a time position of the radio resource is changed in the radio resource change process, notifies the time synchronization control unit of an amount of change in the time position; when the time synchronization control unit is notified of the change amount from the time synchronization control unit, the time synchronization control unit recalculates the transmission delay time based on the notified change amount and notifies the application control unit; the application control unit changes a transmission delay time used when generating the control information to the transmission delay time notified by the time synchronization control unit, or changes a timing for transmitting the control information based on the transmission delay time notified by the time synchronization control unit. A communication system comprising:

7. The network is a star topology network with the master mobile station at the center.

7. The communication system according to claim 6.

8. In a network including a plurality of mobile stations capable of terminal-to-terminal communication and realizing time-synchronized communication, a synchronization control method is executed by a mobile station operating as a master mobile station that transmits control information generated by a cooperative operation control device that controls a controlled device by taking into account a transmission delay time in an information transmission path between the controlled device and the mobile station, the synchronization control method comprising: A first step of determining and changing a radio resource to be used in the terminal-to-terminal communication with a remote mobile station which is a mobile station to which the controlled device, which is a destination of the control information, is connected; a second step of checking whether a time position of the wireless resource has been changed when the wireless resource has been changed in the first step, and notifying a time synchronization control unit that calculates the transmission delay time of an amount of change in the time position if the time position has been changed; A synchronization control method comprising:

9. In a network including a plurality of mobile stations capable of terminal-to-terminal communication and realizing time-synchronized communication, a control circuit controls a mobile station that operates as a master mobile station to transmit control information generated by a cooperative operation control device that controls a controlled device by terminal-to-terminal communication, taking into account a transmission delay time in an information transmission path between the controlled device and the cooperative operation control device, A first step of determining and changing a radio resource to be used in the terminal-to-terminal communication with a remote mobile station which is a mobile station to which the controlled device, which is a destination of the control information, is connected; a second step of checking whether a time position of the wireless resource has been changed when the wireless resource has been changed in the first step, and notifying a time synchronization control unit that calculates the transmission delay time of an amount of change in the time position if the time position has been changed; A control circuit for causing the mobile station to execute the above steps.

10. In a network including a plurality of mobile stations capable of terminal-to-terminal communication and realizing time-synchronized communication, a storage medium stores a program for controlling a mobile station that operates as a master mobile station that transmits control information generated by a cooperative operation control device that controls a controlled device by taking into account a transmission delay time in an information transmission path between the controlled device and the mobile station, The program is A first step of determining and changing a radio resource to be used in the terminal-to-terminal communication with a remote mobile station which is a mobile station to which the controlled device, which is a destination of the control information, is connected; a second step of checking whether a time position of the wireless resource has been changed when the wireless resource has been changed in the first step, and notifying a time synchronization control unit that calculates the transmission delay time of an amount of change in the time position if the time position has been changed; A storage medium for causing the mobile station to execute the above.

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