Measurement system and time information correction method

Abstract

To provide a measurement system capable of improving accuracy of time at low cost with a simple configuration.SOLUTION: A measurement system includes: a measurement device 1 providing a 1PPS signal input part 11 for receiving a 1PPS signal generated by an external signal generation device 3 and outputting it to a PTP time control part 12, and a PTP time control part 12 for performing PTP time control by referring to the 1PPS signal from the 1PPS signal input part 11; and a control PC 2 for transmitting time information acquired from an NTP server 100 and processing delay estimation information to the PTP time control part 12 by user's operation onto an operation part 21, wherein the PTP time control part 12 corrects the time information received from the control PC 2 with including the processing delay estimation information by referring to the 1PPS signal from the 1PPS signal input part 11, and uses it as PTP time information.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a measurement system that simulates an O-RAN (Open-Radio Access Network) O-DU (O-RAN Distributed Unit). [Background technology]

[0002] In wireless communication networks, one architecture for the Radio Access Network (RAN) that is located between the core network and terminals and consists of base stations that control the wireless layer is the C-RAN (Centralized RAN), which extends multiple wireless units from the baseband processing unit of a centrally installed base station device and connects them via optical fiber or other means.

[0003] In C-RAN, there are insufficient standard specifications for the interface between the baseband processing unit and the radio unit, and many areas are specified independently by each vendor, making it difficult to achieve interoperability between baseband processing units and radio units from different vendors.

[0004] To solve these problems, the O-RAN fronthaul specification was formulated, which divides the functions of the radio access network into the O-DU, which acts as the baseband processing unit, and the O-RAN Radio Unit (O-RU), which acts as the radio unit, and specifies the functions of each.

[0005] The O-RAN fronthaul specifications include the C / U / S-Plane (Control, User and Synchronization Plane) specifications, which define the details of equipment operation, and the M-Plane (Management Plane) specifications.

[0006] High synchronization accuracy is required between the O-DU and O-RU to realize coordinated control that requires time synchronization between the O-RUs, such as Carrier Aggregation (CA) using multiple O-RUs and Multiple Input Multiple Output (MIMO).

[0007] For example, in order to establish a connection between a mobile station and a base station, high synchronization accuracy is essential for calculating the SFN (System Frame Number) required by the O-RAN standard (O-RAN.WG4.CUS(v11 Sec.11.7.2)).

[0008] The O-RAN fronthaul specifications support PTP (Precision Time Protocol) and SyncE (Synchronous Ethernet (registered trademark)) as S-Plane protocols, which achieve high synchronization accuracy on the O-RU side by synchronizing with the high-performance O-DU side clock.

[0009] Patent document 1 describes that a device is placed between the O-DU and the O-RU, which evaluates the first reference signal by comparing a first reference signal recovered using a synchronization signal received from the O-DU with a second reference signal generated from a time signal obtained from a satellite that constitutes the GNSS (Global Navigation Satellite System), generates a new synchronization signal based on the evaluation result, and transmits it to the O-RU, and then performs appropriate synchronization processing based on the synchronization signal. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Patent Publication No. 2022-40947 Summary of the Invention [Problem to be solved by the invention]

[0011] As described in Patent Document 1, one possible way to improve synchronization accuracy is to receive time signals from satellites that make up the GNSS. However, if a GNSS receiver is included in the configuration of the measuring instrument, the configuration becomes complicated, the measurement system becomes larger, and the cost also increases.

[0012] Furthermore, when using NTP (Network Time Protocol) for time synchronization, the accuracy is poor, on the order of milliseconds, and delays within the device must also be taken into consideration.

[0013] As a result, there was a problem in that the time accuracy criteria for measuring devices as specified in the O-RAN specifications could not be met.

[0014] SUMMARY OF THE INVENTION An object of the present invention is to provide a measurement system that can improve the accuracy of time at low cost with a simple configuration. [Means for solving the problem]

[0015] The measurement system of the present invention is a measurement system comprising a measurement instrument that simulates an O-RAN O-DU and an external device that controls the measurement instrument to perform measurements, wherein the measurement instrument comprises a PTP time control unit that performs PTP time control between the measurement instrument and an O-RAN O-RU, and the external device transmits to the PTP time control unit processing delay expected information including a processing delay time that occurs when transmitting information from the preset external device to the PTP time control unit, and time information acquired from an NTP server, and the PTP time control unit corrects the time information received from the external device, including the processing delay expected information, by referring to a 1PPS signal input from outside, and uses the corrected time information as PTP time information.

[0016] With this configuration, the time information obtained from the NTP server is corrected by referencing the externally input 1PPS signal, including information on expected processing delays, and used as the PTP time information. This makes it possible to improve time accuracy inexpensively with a simple configuration.

[0017] In addition, the time information correction method of the present invention is a time information correction method for a measurement system that includes a PTP time control unit that performs PTP time control between an O-RU of an O-RAN, a measurement instrument that simulates an O-DU of an O-RAN, and an external device that controls the measurement instrument to perform measurements, and includes the steps of: the external device transmitting to the PTP time control unit estimated processing delay information including a processing delay time that occurs when transmitting information from the preset external device to the PTP time control unit, and time information acquired from an NTP server; and the PTP time control unit correcting the time information received from the external device, including the estimated processing delay information, by referring to a 1PPS signal input from outside, and using the corrected time information as PTP time information.

[0018] With this configuration, the time information obtained from the NTP server is corrected by referencing the externally input 1PPS signal, including information on expected processing delays, and used as the PTP time information. This makes it possible to improve time accuracy inexpensively with a simple configuration. [Effects of the Invention]

[0019] The present invention can provide a measurement system that can improve the accuracy of time at low cost with a simple configuration. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a block diagram of a measurement system according to one embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing an example of a GNSS time setting button of a measurement system according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, a measurement system according to an embodiment of the present invention will be described in detail with reference to the drawings.

[0022] In FIG. 1, a measurement system according to one embodiment of the present invention includes a measurement device 1 and a control PC 2 as an external device.

[0023] The measuring device 1 is connected to a control PC 2 and operates under the control of the control PC 2. Note that the measuring device 1 may incorporate the functions of the control PC 2 to form an integrated measuring device 1.

[0024] The measuring instrument 1 is configured by a computer unit that includes, for example, a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), flash memory, a hard disk drive, an input port, and an output port.

[0025] This computer unit is configured so that the CPU can control devices connected to the input and output ports by executing an OS (Operating System) stored in a hard disk drive, for example.

[0026] The measuring device 1 includes a 1PPS signal input unit 11, a PTP time control unit 12, and an SFN calculation unit 13.

[0027] The 1PPS signal input unit 11 receives a 1PPS (1 Pulse Per Second) signal generated by an external signal generating device 3 and outputs it to the PTP time control unit 12 .

[0028] The PTP time control unit 12 performs PTP time control by referring to the 1PPS signal from the 1PPS signal input unit 11.

[0029] The control PC 2 is configured by a computer unit including, for example, a CPU, a RAM, a ROM, a flash memory, a hard disk drive, an input port, an output port, an operation unit 21, and a display unit 22.

[0030] The operation unit 21 is configured with input devices such as a keyboard, a mouse, and a touch panel, and outputs information input by operation to the CPU.

[0031] The display unit 22 is configured, for example, with an image display device such as a liquid crystal display, and displays images for inputting information necessary for setting up the test, images showing the status during the test, and the like.

[0032] This computer unit is configured so that the CPU can control devices connected to the input and output ports by executing an OS stored in the hard disk drive.

[0033] The control PC 2 obtains time information from an NTP server 100 that distributes time information by NTP.

[0034] The control PC2 stores information about expected processing delays when transmitting information to the PTP time control unit 12. The expected processing delay information is information about the expected total processing delay that will occur in the control PC2 and the PTP time control unit 12. The expected processing delay information includes at least either a fixed processing delay calculated in advance as a hardware specific value for each of the control PC2 and the PTP time control unit 12, or an actually measured processing delay that varies depending on the processing load of each of the hardware of the control PC2 and the PTP time control unit 12. The actual measurement may be, for example, calculating the time difference between the GNSS time and an uncorrected state with no expected processing delay. Examples of the GNSS include GPS (Global Positioning System), GLONASS, BeiDou, Galileo, and Michibiki.

[0035] When the time setting function is selected by the user operating the operation unit 21, the control PC 2 causes the display unit 22 to display, for example, a GNSS time setting button 23 as shown in FIG.

[0036] When the GNSS time setting button 23 is selected by the user operating the operation unit 21, the control PC 2 transmits the expected processing delay information together with the time information acquired from the NTP server 100 to the PTP time control unit 12.

[0037] The PTP time control unit 12 corrects the time information received from the control PC 2, including the expected processing delay information, by referring to the 1PPS signal from the 1PPS signal input unit 11, and uses the corrected time information as PTP time information.

[0038] To establish a connection between a mobile station and a base station, the SFN must be calculated based on accurate time information. The SFN calculation unit 13 calculates the SFN based on the PTP time information. The calculated SFN is stored as an information element in a communication packet with the O-RU 4.

[0039] As described above, in the embodiment described above, the control PC 2 stores estimated processing delay information when transmitting information to the PTP time control unit 12, and when the GNSS time setting button 23 is selected by a user operating the operation unit 21, the control PC 2 transmits the estimated processing delay information to the PTP time control unit 12 along with the time information acquired from the NTP server 100. The PTP time control unit 12 corrects the time information received from the control PC 2, including the estimated processing delay information, with reference to the 1PPS signal from the 1PPS signal input unit 11, and uses the corrected information as PTP time information.

[0040] This allows the time information obtained from the NTP server 100 to be corrected, including the expected processing delay information, by referring to the 1PPS signal. This allows the time accuracy to be improved inexpensively with a simple configuration. Therefore, in order to establish a connection between a mobile device and a base station, the SFN can be calculated based on the correct time information.

[0041] While an embodiment of the present invention has been disclosed, it will be apparent to one skilled in the art that modifications may be made thereto without departing from the scope of the present invention, and it is intended that all such modifications and equivalents be included in the following claims. [Explanation of symbols]

[0042] 1 Measuring instrument 2 Control PC (external device) 3 Signal generation device 4 O-RU 11 1PPS signal input section 12 PTP time control section 13 SFN calculation part 21 Control section 22 Display section 23 GNSS time setting button 100 NTP servers

Claims

1. A measurement system comprising a measuring device (1) that simulates an O-DU of an O-RAN, and an external device (2) that controls the measuring device to perform measurements, The measuring device includes a PTP time control unit (12) that performs PTP time control between the measuring device and an O-RU (4) of an O-RAN, The external device transmits to the PTP time control unit processing delay expected information including a processing delay time that occurs when transmitting information from the external device to the PTP time control unit, and time information acquired from an NTP server (100); The PTP time control unit corrects the time information received from the external device by referring to a 1PPS signal input from the outside, including information on expected processing delays, and uses the corrected time information as PTP time information.

2. A time information correction method for a measurement system including a PTP time control unit (12) that performs PTP time control between an O-RAN O-RU (4), a measurement device (1) that simulates an O-RAN O-DU, and an external device (2) that controls the measurement device to perform measurements, The external device transmits to the PTP time control unit processing delay expected information including a processing delay time that occurs when transmitting information from the external device to the PTP time control unit, which is preset, and time information acquired from an NTP server (100); A time information correction method comprising a step in which the PTP time control unit corrects the time information received from the external device by referring to a 1PPS signal input from the outside, including information on expected processing delays, and uses the corrected time information as PTP time information.

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