Communication device, communication device control method and program

Abstract

To stably realize time synchronization of predetermined accuracy.SOLUTION: A communication device that constitutes a network between communication devices comprises: determination means that determines whether or not a base station existing outside of the network corresponds to time synchronization having a predetermined accuracy; time synchronization processing means that synchronizes time of the communication device with time of the base station when the base station corresponds to time synchronization having the predetermined accuracy; and control means that controls the communication device. The control means operates the communication device as a time synchronization source for the other communication device within the network when the time of the communication device synchronizes with the time of the base station.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a communication device, a control method for a communication device, and a program. [Background technology]

[0002] When forming a network between devices to perform time synchronization, one device within the network may obtain time information from a device outside the network and use that obtained time information to perform time synchronization within the network.

[0003] For example, a network is formed between multiple cameras, and one camera acquires time information from outside the network. Then, by synchronizing the time between the cameras in the network, it becomes possible to organize multiple images taken by multiple users in chronological order, thereby improving the efficiency of editing work. Specific examples of devices outside the network that can receive synchronization signals include GPS, radio-controlled clocks, and high-precision clocks via wired connections (Patent Document 1).

[0004] Additionally, studies are currently underway to enable highly accurate time synchronization at 5G base stations using the Precision Time Protocol (PTP) that complies with the IEEE (Institute of Electrical and Electronics Engineers) (registered trademark) 1588 standard. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-111654 Summary of the Invention [Problem to be solved by the invention]

[0006] In Patent Document 1, a synchronization signal is received from a GPS or radio-controlled clock, or from a high-precision clock via a wired connection. However, GPS cannot perform time synchronization indoors because it cannot measure positioning. Furthermore, it is unclear whether the accuracy of the received time is acceptable to the user.

[0007] Furthermore, while connecting to a 5G base station that supports the aforementioned PTP enables highly accurate time synchronization, connecting to a base station that does not support PTP will not achieve highly accurate time synchronization, even though the connection to the base station was made in the hope of achieving this.

[0008] The present invention has been made in view of the above-mentioned problems, and aims to provide a technique for stably realizing time synchronization with a predetermined accuracy. [Means for solving the problem]

[0009] A communication device according to one aspect of the present invention that achieves the above object comprises: A communication device that configures a network between communication devices, Located outside the network 3GPP (Third Generation Partnership Project) standard a determination means for determining whether a base station supports time synchronization with a predetermined accuracy based on information related to time synchronization received from the base station; a time synchronization processing means for synchronizing the time of the communication device with the time of the base station when the base station supports time synchronization with the predetermined accuracy; a control means for controlling the communication device; communication means for communicating with the base station; Equipped with When the time of the communication device is synchronized with the time of the base station, the control means causes the communication device to operate as a time synchronization source for other communication devices within the network. 、 The determining means determines that the base station supports time synchronization with the predetermined accuracy when TimeInfo is included in an SIB (System Information Block) 9 received from the base station via the communication means. It is characterized by the following. [Effects of the Invention]

[0010] According to the present invention, time synchronization with a predetermined accuracy can be stably achieved. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a block diagram illustrating an example of a hardware configuration of a communication device according to an embodiment. [Figure 2] FIG. 2 is a block diagram illustrating an example of a software configuration of a communication device according to an embodiment. [Figure 3] FIG. 1 is a diagram illustrating an example of the configuration of a communication system according to an embodiment. [Figure 4] 10 is a flowchart illustrating a procedure of a process performed by a communication device according to an embodiment when a grandmaster is established in a local network. [Figure 5] 10 is a flowchart illustrating a procedure of a process performed by a communication device according to an embodiment after a grandmaster is established in a local network. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the claimed invention. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0013] <Hardware configuration> 1 is a block diagram illustrating an example of a hardware configuration of a communication device according to an embodiment. The communication device 100 includes a control unit 101, a storage unit 102, an operation unit 103, a display unit 104, a wireless communication unit 105, and a speaker 106.

[0014] The control unit 101 is, for example, one or more CPUs (Central Processing Units), and controls the operation of each component of the communication device 100 in accordance with input signals and programs described below. Note that instead of the control unit 101 controlling the entire device, the entire device may be controlled by a plurality of hardware devices sharing the processing. The storage unit 102 stores one or more control programs executed by the control unit 101, as well as various information such as communication parameters and captured image data. The control unit 101 executes the control programs stored in the storage unit 102 to perform various operations described below.

[0015] The operation unit 103 is used to receive instructions from a user for the communication device 100. For example, it is a physical operation unit such as a keyboard or physical buttons. Alternatively, when the display unit 104 functions as a touch panel that receives touch operations, the display unit 104 can also be used as the operation unit.

[0016] The operation unit 103 accepts a selection operation to operate the communication device 100 as either a master device operating as a wireless LAN access point or a slave device operating as a station. The operation unit 103 can also accept a setting of a first mode (power saving mode) in which the communication device 100 operates in a power saving state or a second mode (normal operation mode) in which the communication device 100 does not operate in a power saving state.

[0017] The display unit 104 is a display unit that displays various types of information, and has a function of outputting visually perceptible information such as an LCD (Liquid Crystal Display) or an LED (Light Emitting Diode).

[0018] The wireless communication unit 105 performs wireless LAN communication in accordance with the 3GPP (Third Generation Partnership Project) (registered trademark) standard or the IEEE (Institute of Electrical and Electronics Engineers) (registered trademark) 802.11a / b / g / n / ac / ax (registered trademark) standard. The speaker 106 is an alarm unit capable of outputting sound information.

[0019] <Software configuration> 2 is a block diagram illustrating an example of a software configuration of a communication device 100 according to an embodiment. The communication device 100 includes a signal receiving unit 201, a signal transmitting unit 202, a data storage unit 203, and a display control unit 204. The communication device 100 also includes a master / slave determination unit 205, a BMCA processing unit 206, a PTP compatibility determination unit 208, a time synchronization processing unit 209, an operation mode confirmation unit 210, and a time error calculation unit 211. The BMCA processing unit 206 includes a Priority1 value setting unit 207.

[0020] The signal receiving unit 201 and the signal transmitting unit 202 respectively receive and transmit signals over a wireless LAN in accordance with the 3GPP (registered trademark) standard or the IEEE802.11a / b / g / n / ac / ax (registered trademark) standard between the opposing device. The signal receiving unit 201 and the signal transmitting unit 202 correspond to the wireless communication unit 105. The data storage unit 203 stores and holds the software itself and information such as authentication information, and corresponds to the storage unit 102.

[0021] A display control unit 204 controls the screen displayed on the display unit 104. A master / slave determination unit 205 determines whether the device itself is operating as a master device or a slave device within the network. A master device operates as an access point of a wireless LAN, and a slave device operates as a station of the wireless LAN.

[0022] The BMCA processing unit 206 operates based on the Best Master Clock Algorithm (BMCA), which automatically determines the optimal grandmaster from among multiple grandmaster candidates. The BMCA processing unit 206 includes a Priority 1 value setting unit 207. This Priority 1 value is information that is compared first among multiple grandmaster candidates when determining a grandmaster based on BMCA. The possible range of Priority 1 values ​​is from 0 to 255, with the one with the smallest value becoming the grandmaster.

[0023] The PTP support determination unit 208 determines whether the base station 500 (described later) supports IEEE (registered trademark) 1588. The time synchronization processing unit 209 performs time synchronization processing with the base station 500 (described later) and the communication devices 300 and 301. Specifically, the time synchronization processing is performed in accordance with the IEEE (registered trademark) 1588 standard or RFC (Request for Comments) (registered trademark) 1305.

[0024] The operation mode confirmation unit 210 confirms the operation mode of the own device. Specifically, the operation mode is one of a plurality of operation modes including a power saving mode that reduces power consumption and a normal mode that does not. The time error calculation unit 211 calculates the time error between the own device and a base station 500, which will be described later.

[0025] <System configuration> 3 is a diagram showing an example of the configuration of a communication system according to an embodiment. The communication system according to this embodiment includes communication devices 100, 300, and 301, a public network 400, and a base station 500. The communication device 100 communicates with the public network 400 in accordance with the 3GPP (registered trademark) standard, while communicating with the communication devices 300 and 301 in accordance with Wi-Fi (registered trademark). Note that the communication devices 300 and 301 have the same configuration as the communication device 100, and therefore a description thereof will be omitted.

[0026] <Processing> 4 is a flowchart showing the procedure of processing when the communication device 100 is established as a grandmaster in a network formed between communication devices in this embodiment. When the operation unit 103 of the communication device 100 accepts an operation to set whether the device operates as a master device or a slave device, a notification is sent to the control unit 101.

[0027] The control unit 101 determines whether the communication device 100 has been selected as a master device using the master / slave determination unit 205 (S401). If selected as a master device, the communication device 100 operates as an access point of the wireless LAN. The control unit 101 activates the wireless communication unit 105, sets the Priority1 value to 255 using the Priority1 value setting unit 207, and then starts communication with the base station 500 in accordance with the 3GPP standard (registered trademark) (S402).

[0028] Here, the Priority1 value is set to the maximum value of 255 in order to prevent the communication device 100 from becoming a grandmaster in the network formed by the base station 500 through BMCA when connected to a base station 500 outside the network. When the wireless communication unit 105 receives system information transmitted as a broadcast signal from the base station 500 or an RRC (Radio Resource Control) message exchanged with the base station 500, the wireless communication unit 105 notifies the control unit 101.

[0029] The control unit 101 checks whether a parameter called "TimeInfo" (described later) is included in SIB (System Information Block) 9, which is one of the blocks making up the received system information, using the PTP compatibility determination unit 208. Furthermore, the control unit 101 checks whether "AbsoluteTimeInfo" (described later) is included in the received RRC message (S403).

[0030] TimeInfo contains four items: "TimeInfoUTC" (required), "DayLightSavingTime" (optional), "LeapSeconds" (optional), and "LocalTimeOffset" (optional). If only the required items are included, UTC (Coordinated Universal Time) time information can be obtained. If the optional items are also included, time with the same accuracy as GPS can be obtained. However, the time included in TimeInfo does not include the communication delay required between the base station 500 and the communication device 100. AbsoluteTimeInfo refers to absolute time consisting of year, month, day, hour, minute, and second.

[0031] If the control unit 101 confirms TimeInfo or AbsoluteTimeInfo, it determines that time synchronization with a base station 500 located outside the network with a predetermined accuracy is possible, and starts time synchronization (S404). In this case, the control unit 101 uses the time synchronization processing unit 209 to perform time synchronization processing with the base station 500 via the wireless communication unit 105 in accordance with the IEEE (registered trademark) 1588 standard. The control unit 101 stores information indicating that the communication device 100 is a master device and a grandmaster in the network formed between the communication devices in the storage unit 102 (S405). Thereafter, the communication device 100 operates as a master and grandmaster device in the network formed between the communication devices. In other words, if the time of the communication device 100 is synchronized with the time of the base station 500, the control unit 101 causes the communication device 100 to operate as a time synchronization source for the other communication devices 300 and 301 in the network.

[0032] The control unit 101 waits for the communication devices 300 and 301 to connect to the communication device 100 via the wireless communication unit 105 (S406). Once the communication devices 300 and 301 are connected, the control unit 101 performs time synchronization processing with the communication devices 300 and 301 via the wireless communication unit 105 using the time synchronization processing unit 209 (S407). This completes time synchronization between the communication devices.

[0033] On the other hand, if neither TimeInfo nor AbsoluteTimeInfo can be confirmed in S403, the process proceeds to S408. Then, the control unit 101 determines that time synchronization processing in accordance with the IEEE (registered trademark) 1588 standard with the base station 500 is impossible, and notifies the user of the determination result via the display unit 104 (S408). The display control unit 204 controls the display unit 104 to display information indicating that time synchronization processing in accordance with the IEEE (registered trademark) 1588 standard is impossible, and information for allowing the user to select whether or not to still perform time synchronization with the base station 500. Alternatively or in addition to this, the notification may be made by voice using the speaker 106.

[0034] Then, the control unit 101 determines whether to perform time synchronization based on the user's selection (S409). If the user wishes to perform time synchronization with the base station 500, the user uses the operation unit 103 to select time synchronization, and the control unit 101 is notified of the selection result. The control unit 101 uses the time synchronization processing unit 209 to perform time synchronization processing with the base station 500 via the wireless communication unit 105 in accordance with RFC (registered trademark) 1305 (S410). Thereafter, the same processing as that from S405 to S407 is performed.

[0035] Furthermore, if the communication device 100 is selected as a slave device in S401, the process proceeds to S411. Then, the communication device 100 operates as a slave device in the network formed between the communication devices (S411). In this case, the communication device 100 operates as a station of the wireless LAN. Thereafter, the control unit 101 searches for a communication device (e.g., communication device 300 or communication device 301) that will become the master device via the wireless communication unit 105 (S412). If a communication device that will become the master device is detected, the process proceeds to S413. The control unit 101 uses the time synchronization processing unit 209 to perform time synchronization processing with the communication device that will become the master device via the wireless communication unit 105 (S413).

[0036] If the user selects not to synchronize the time with the base station 500 in S409, the operation unit 103 notifies the control unit 101. Upon receiving the notification, the control unit 101 stops the wireless communication unit 105. This completes the series of processes shown in FIG.

[0037] It is also possible to extract the time information from either TimeInfo or AbsoluteTimeInfo acquired in S403 and set it in the time synchronization processing unit 209 without performing time synchronization with the base station 500 in S404 or S410. However, in this case, an error may occur due to the communication time required between the communication device 100 and the base station 500.

[0038] Next, FIG. 5 is a flowchart showing a procedure of processing after the communication device 100 is established as a grandmaster in a network formed between communication devices according to an embodiment.

[0039] The operation unit 103 can accept the setting of a first mode (power saving mode) in which the communication device 100 operates in a power saving state, or a second mode (normal operation mode) in which the communication device 100 does not operate in a power saving state. When the operation mode of the communication device 100 (for example, the power saving mode, the normal operation mode, etc.) is set by the operation unit 103, the control unit 101 stores the operation mode in the storage unit 102. Note that the setting of the operation mode may be performed before the communication device 100 is selected to operate as a grandmaster.

[0040] The control unit 101 uses the operation mode check unit 210 to determine whether the operation mode currently set in the communication device 100 is a power saving mode that reduces power consumption (S501). If the power saving mode is set, the control unit 101 performs time synchronization with the base station 500 via the wireless communication unit 105 using the time synchronization processing unit 209 after a certain time T1 has elapsed (S502).

[0041] Here, the fixed time T1 is, for example, a first predetermined time counted from the time when the previous time synchronization was performed. The control unit 101 uses the time error calculation unit 211 to check the error E between the time of the communication device 100 before the time synchronization in S502 and the time of the communication device 100 after the time synchronization, and stores the error E in the storage unit 102 (S503). After checking, the control unit 101 stops the function of the wireless communication unit 105 to communicate according to the 3GGP standard (S504).

[0042] The control unit 101 continues to suspend the operation of the wireless communication unit 105 until the time error with the base station 500 exceeds the allowable value Z (S505). That is, it determines whether or not the time error has exceeded the allowable value Z, and waits until it does. More specifically, the control unit 101 uses the time error calculation unit 211 to calculate the time error per unit time with the base station 500, T1 / E=Y, from the fixed time T1 required in S502 and the time error E confirmed in S503. Then, since the time error increases by Y for each unit time, the control unit 101 uses the time error calculation unit 211 to confirm whether or not the total value of the error that has increased over time has exceeded the allowable value Z.

[0043] In this way, the control unit 101 calculates the value of the time error occurring per unit time based on the fixed time T1 and the time error E occurring as the fixed time T1 elapses, calculates the current time error based on this value and the time elapsed since time synchronization was performed, and then determines whether the current time error exceeds the allowable value Z.

[0044] If the error exceeds the allowable value Z, time synchronization is necessary, so the control unit 101 activates the function of the wireless communication unit 105 to communicate in accordance with the 3GPP standard, and resumes communication with the base station 500 (S506).

[0045] The control unit 101 uses the time synchronization processing unit 209 to perform time synchronization with the base station 500 via the wireless communication unit 105 (S507). Thereafter, the control unit 101 uses the time synchronization processing unit 209 to perform time synchronization with the communication devices 300 and 301 within the communication device network via the wireless communication unit 105 (S508). Thereafter, the control unit 101 determines whether to end the processing (S510), and if not, returns to S501 and repeats the subsequent processing. The case where the processing ends can be, for example, when the power of the communication device 10 is turned off by a user operation or when an input to stop the time synchronization processing is received.

[0046] On the other hand, if it is determined in S501 that a mode other than the power saving mode (for example, the normal operation mode) is set in the communication device 100, the process proceeds to S509. After a predetermined time T2, which is shorter than the predetermined time T1 in S502, has elapsed, the control unit 101 performs time synchronization with the base station 500 via the wireless communication unit 105 using the time synchronization processing unit 209 (S509).

[0047] Here, the fixed time T2 is, for example, a second predetermined time counted from the time of the previous time synchronization, where T1>T2. That is, when operating in power saving mode, the frequency of time synchronization with the base station 500 can be reduced to achieve further power savings. On the other hand, when a mode other than power saving mode (for example, normal operation mode) is set, the frequency of time synchronization can be increased to maintain the time information of the communication device 100 at a more accurate value. Then, proceed to S508. The above is the series of processes shown in FIG. 5.

[0048] As described above, in this embodiment, when the communication device 100 performs time synchronization with the base station 500, the time synchronization is performed after determining whether or not time synchronization is possible with a predetermined time accuracy based on communication with the base station 500. This allows the user to confirm whether time synchronization with a desired accuracy is possible before performing time synchronization.

[0049] As described above, according to this embodiment, it is possible to stably achieve time synchronization with a predetermined accuracy. It is also possible to avoid a situation where a device is connected to a base station in the hope of achieving time synchronization with a predetermined accuracy, but is unable to achieve time synchronization with a predetermined accuracy.

[0050] (Other embodiments) The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program.The present invention can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0051] The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0052] 100: communication device, 101: control unit, 102: storage unit, 103: operation unit, 104: display unit, 105: wireless communication unit, 106: speaker, 300, 301: communication device, 400: public network, 500: base station

Claims

1. A communication device that configures a network between communication devices, a determination means for determining whether a base station conforming to the 3GPP (Third Generation Partnership Project) standard that exists outside the network supports time synchronization with a predetermined accuracy based on information related to time synchronization received from the base station; a time synchronization processing means for synchronizing the time of the communication device with the time of the base station when the base station supports time synchronization with the predetermined accuracy; a control means for controlling the communication device; communication means for communicating with the base station; the control means, when the time of the communication device is synchronized with the time of the base station, causes the communication device to operate as a time synchronization source for other communication devices within the network; The determination means determines that the base station supports time synchronization with the predetermined accuracy when TimeInfo is included in SIB (System Information Block) 9 received from the base station via the communication means.

2. The communication device described in Claim 1, characterized in that the network is a network based on a communication standard different from the 3GPP standard.

3. further comprising an operation means for accepting an operation from a user, 2. The communication device according to claim 1, wherein the operation means accepts a selection operation to operate the communication device as either a master device operating as an access point of a wireless LAN or a slave device operating as a station.

4. 4. The communication device according to claim 3, further comprising a communication means for communicating with the base station when the communication device is selected as the master device.

5. A communication device that configures a network between communication devices, a determination means for determining whether a base station outside the network supports time synchronization with a predetermined accuracy based on information about time synchronization received from the base station; a time synchronization processing means for synchronizing the time of the communication device with the time of the base station when the base station supports time synchronization with the predetermined accuracy; a control means for controlling the communication device; an operation means for receiving a selection operation from a user to operate the communication device as either a master device operating as an access point of a wireless LAN or a slave device operating as a station; a communication means for communicating with the base station when the communication device is selected as the master device, the control means, when the time of the communication device is synchronized with the time of the base station, causes the communication device to operate as a time synchronization source for other communication devices within the network; The communication device is characterized in that the communication means communicates with the base station by setting a Priority 1 value of PTP (Precision Time Protocol) to a maximum value of 255.

6. 6. The communication device according to claim 5, wherein the determination means determines that the base station supports time synchronization with the predetermined accuracy when TimeInfo is included in an SIB (System Information Block) 9 received from the base station via the communication means.

7. 5. The communication device according to claim 1, wherein the determining unit determines that the base station supports time synchronization with the predetermined accuracy when an RRC (Radio Resource Control) message received from the base station via the communication unit includes AbsoluteTimeInfo.

8. The communication device according to any one of claims 1 to 4, characterized in that when the determination means determines that the base station does not support time synchronization with the specified accuracy, the control means causes the display means to display information indicating that the base station does not support time synchronization with the specified accuracy.

9. A communication device as described in any one of claims 1 to 4, characterized in that when the time of the communication device is synchronized with the time of the base station, the control means causes the communication device to operate as a master device and a grand master in the network with respect to other communication devices in the network.

10. A communication device described in any one of claims 1 to 4, characterized in that the communication means communicates with the base station by setting the Priority 1 value of PTP (Precision Time Protocol) to the maximum value of 255.

11. A communication device that configures a network between communication devices, a determination means for determining whether a base station outside the network supports time synchronization with a predetermined accuracy based on information about time synchronization received from the base station; a time synchronization processing means for synchronizing the time of the communication device with the time of the base station when the base station supports time synchronization with the predetermined accuracy; a control means for controlling the communication device; an operation means for receiving an operation from a user, the control means, when the time of the communication device is synchronized with the time of the base station, causes the communication device to operate as a time synchronization source for other communication devices within the network; the operation means is capable of accepting setting of a first mode in which the communication device operates in a power saving state or a second mode in which the communication device does not operate in the power saving state; The time synchronization processing means When the communication device is operating as the time synchronization source in the first mode, performing time synchronization with the base station after a first predetermined time has elapsed; When the communication device is operating as the time synchronization source in the second mode, the communication device performs time synchronization with the base station after a second predetermined time shorter than the first predetermined time has elapsed.

12. The communication device according to claim 11, characterized in that the control means, after time synchronization with the base station performed after the first predetermined time has elapsed, checks a time error that has occurred between the base station and the communication device, and stops communication with the base station.

13. The control means calculating a value of a time error occurring per unit time based on the first predetermined time and a time error occurring as the first predetermined time elapses; Calculate the current time error based on this value and the elapsed time since time synchronization was performed, 13. The communication device according to claim 12, wherein when the current time error exceeds an allowable value, communication with the base station is resumed.

14. 14. The communication device according to claim 13, wherein the time synchronization processing means performs time synchronization with the base station when communication with the base station is resumed.

15. A control method for communication devices that form a network between communication devices, comprising: a determining step of determining whether a base station conforming to the 3GPP (Third Generation Partnership Project) standard that exists outside the network supports time synchronization with a predetermined accuracy based on information related to time synchronization received from the base station; a time synchronization process step of synchronizing the time of the communication device with the time of the base station when the base station supports time synchronization with the predetermined accuracy; a control step of controlling the communication device; a communication step of communicating with the base station, In the control step, when the time of the communication device is synchronized with the time of the base station, the communication device is operated as a time synchronization source for other communication devices in the network; In the determination step, if TimeInfo is included in SIB (System Information Block) 9 received from the base station via the communication step, it is determined that the base station supports time synchronization with the predetermined accuracy.

16. A program for causing a computer to function as the communication device according to any one of claims 1 to 14.

17. The communication device described in Claim 8, characterized in that the control means displays second information inquiring the user as to whether or not to perform time synchronization along with the information indicating incompatibility, and, upon receipt of a user operation not to perform time synchronization, further executes control to stop the communication means' function of communicating with a base station based on the 3GPP standard.

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