Base station radio device, information processing method, and computer program

Abstract

To provide a base station radio device, an information processing method, and a computer program that calculate the propagation time of an analog communication signal between a base station master and a base station slave, and perform correction processing taking into account a delay parameter to synchronize the communication schedule of the base station.SOLUTION: A distributed MIMO base station radio device 100a adds the propagation time of an analog communication signal calculated from the difference between a transmission time and a reception time of the analog communication signal propagating between a mixed signal calculation device and a distributed antenna to the value of a signal delay time generated in the distributed MIMO base station radio device, and responds with the value of the signal delay time in response to a request from a CU (Central Unit) and a base station control device composed of a CU.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a method for time synchronization and schedule management of communication signals in a base station radio device. [Background technology]

[0002] In the fifth generation mobile communication system, radio waves in the high frequency range such as millimeter waves are used to achieve high speed and large capacity. As the radio wave frequency increases, its tendency to travel in a straight line increases, so it is desirable to perform high frequency wireless communication within line of sight. For this reason, the introduction of distributed MIMO (Multiple Input Multiple Output), which expands the area where line-of-sight communication can be performed by distributing base stations, is being considered. Since distributed MIMO requires the installation of many access points, it is required to construct access points at low cost and with low power consumption. For this reason, as shown in Fig. 1 in Non-Patent Document 1, for example, it is assumed that a device that was previously integrated as a radio device (RU: Radio Unit) will be separated into a distributed antenna (DA: Distributed Antenna) equipped mainly with an analog front end and an antenna, and a mixed signal processing unit (MSPU: Mixed Signal Processing Unit) equipped with digital signal processing such as modulation and demodulation, and communication signals of multiple distributed antennas will be processed by one mixed signal processing unit.

[0003] In the 5th generation mobile communication system, switching between transmission and reception is performed by time division duplex (TDD), which requires precise time control of communication schedules. To perform time division duplex and suppress radio interference between base stations while at the same time removing guard bands to increase the efficiency of radio resource usage, it is necessary to synchronize the timing of switching between transmission and reception between base stations. For this reason, synchronization with the International Atomic Time (TAI: Temps Atomique International) is required. Furthermore, high time synchronization accuracy is required depending on the communication technology being introduced, such as carrier aggregation and MIMO. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] Noriaki Tawa, Toshihide Kuwabara, Yasushi Maruta, Tomoya Kaneko, “28 GHz Distributed-MIMO Comprehensive Antenna Calibration for 5G Indoor Spatial Division Multiplex”, 2021 IEEE MTT-S International Microwave Symposium, June 2021. Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present disclosure is to provide a base station radio device, an information processing method, and a computer program capable of solving the above-mentioned technical problems. As an example, an object of the present disclosure is to provide a base station radio device, an information processing method, and a computer program capable of time synchronization in a base station. [Means for solving the problem]

[0006] One aspect of the base station radio device includes a calculation means for calculating a value representing a propagation time of an analog communication signal propagating between a base station slave unit and the base station parent unit based on an output time of a downlink signal output in an analog manner by a base station parent unit included in the base station radio device to a base station slave unit included in the base station radio device, and an input time of the downlink signal input to the base station slave unit, and a correction means for correcting a parameter representing a signal delay time within the base station radio device based on the value representing the propagation time of the analog communication signal.

[0007] One aspect of the information processing method involves a base station parent unit provided in a base station radio device calculating a propagation time of an analog communication signal propagating between the base station slave unit and the base station parent unit based on an output time of a downlink signal output in an analog manner to a base station slave unit provided in the base station radio device and an input time of the downlink signal input to the base station slave unit, and correcting a parameter representing a signal delay time within the base station radio device based on a value representing the propagation time of the analog communication signal.

[0008] One aspect of the computer program causes a computer to calculate a propagation time of an analog communication signal propagating between a base station slave unit and a base station master unit based on an output time of a downlink signal output in an analog manner by a base station master unit provided in a base station radio device to a base station slave unit provided in the base station radio device and an input time of the downlink signal input to the base station slave unit, and to correct a parameter representing a signal delay time within the base station radio device based on a value representing the propagation time of the analog communication signal. Effect of the Invention

[0009] According to each aspect of the above-mentioned base station radio device, information processing method, and computer program, the propagation time of the analog communication signal between the base station parent unit and the base station child unit is calculated and correction processing is performed taking into account the delay parameter, so that the communication schedule of the base station can be synchronized. [Brief description of the drawings]

[0010] [Figure 1] 1 is a block diagram showing an example of the configuration of a base station radio device according to the present disclosure. [Diagram 2] 1 is a block diagram showing an example of the configuration of a base station radio device according to the present disclosure. [Diagram 3] 1 is a diagram showing an example of a method for calculating an analog communication signal propagation time in a base station radio device according to the present disclosure. [Figure 4] A conceptual diagram of delay parameters managed by O-RAN. [Diagram 5]1 is a block diagram showing an example of the configuration of a base station radio device according to the present disclosure. [Figure 6] FIG. 13 is a diagram illustrating an example of the operation of a four-port switch in a base station radio device according to the present disclosure. [Figure 7] 1 is a diagram showing an example of a method for calculating an analog communication signal propagation time of a base station radio device according to the present disclosure. [Figure 8] 1 is a block diagram showing an example of the configuration of a base station radio device according to the present disclosure. [Figure 9] 1 is a block diagram showing an example of an internal structure of an RoF device provided in a base station radio device according to this disclosure. [Figure 10] 1 is a block diagram showing an example of the configuration of a base station radio device according to the present disclosure. [Figure 11] FIG. 2 illustrates an example of a method for synchronizing distributed antennas according to the present disclosure. [Figure 12] 1 is a block diagram showing an example of the configuration of a base station radio device according to the present disclosure. [Figure 13] FIG. 1 illustrates an issue related to synchronization between base stations. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments of a base station radio device, an information processing method, and a computer program will be described with reference to the drawings. [1: First embodiment]

[0012] A base station radio device, an information processing method, and a computer program according to a first embodiment will be described. In the following, a base station radio device, an information processing method, and a computer program according to a first embodiment will be described using a base station radio device 100 according to this disclosure. [1-1: Configuration of base station radio device 100]

[0013] Fig. 1(a) is a block diagram showing the configuration of a base station radio device 100 according to this disclosure. As shown in Fig. 1(a), the base station radio device 100 includes a calculation unit 11 and a correction unit 12. The base station radio device 100 also includes a base station master device and a base station slave device, and provides a wireless communication environment for communication terminals. [1-2: Information Processing Operation Performed by the Base Station Radio Equipment 100]

[0014] The information processing operation performed by the base station radio device 100 will be described with reference to Fig. 1(b). As shown in Fig. 1(b), the calculation unit 11 calculates the propagation time of an analog communication signal propagating between the base station slave and the base station master based on the output time of a downlink signal output by the base station master to the base station slave in an analog manner and the input time of a downlink signal input to the base station slave (step S11). Since the base station slave does not perform digital signal processing, the communication signal exchanged between the base station master and the base station slave is an analog communication signal such as an IF (Intermediate Frequency) signal, an RF (Radio Frequency) signal, or a baseband signal.

[0015] The correction unit 12 corrects a parameter representing a signal delay time in the base station radio equipment based on a value representing the propagation time of the analog communication signal (step S12). The base station radio equipment 100 operates according to the corrected parameter (step S13). The base station radio equipment 100 may start operating according to the corrected parameter. [1-3: Technical Effects of the Base Station Radio Equipment 100]

[0016] One of the issues facing distributed MIMO base stations is time synchronization between base stations. In a distributed MIMO base station radio device, the digital signal processing unit and the analog front-end unit are arranged separately. For this reason, for example, as shown in Fig. 13, the signal propagation time between the mixed signal processing unit and the distributed antennas may differ for each distributed antenna. When the signal propagation times differ, the communication schedules of the base stations may not be synchronized unless the signal propagation times are corrected. This can cause radio interference.

[0017] Information about the communication schedule is sent to the mixed signal processor via the fronthaul connection. In the fronthaul connection, the time required for signal processing in the wireless device 300 is shared as a delay parameter and used to manage the communication schedule. However, since the length of the communication cable between the mixed signal processor and the distributed antenna varies depending on the installation layout of the base station, a mechanism is required to check the propagation time of the communication signal between the mixed signal processor and the distributed antenna and incorporate it into the delay parameter. Time synchronization between base stations is based on the antenna end where the communication radio waves are emitted, so corrections are required that include the calculation processing performed in the base station and the signal propagation time.

[0018] In response to this, the base station radio device 100 according to this disclosure calculates the propagation time of an analog communication signal propagating between the base station slave device and the base station master device, and corrects a parameter representing a signal delay time within the base station radio device based on a value representing the propagation time of the analog communication signal. This allows the base station radio device 100 to perform time synchronization and control the schedule of the communication radio waves output from the base station slave device at accurate time. [2: Second embodiment]

[0019] A second embodiment of the base station radio device, the information processing method, and the computer program will be described below. In the following, the second embodiment of the base station radio device, the information processing method, and the computer program will be described using the distributed MIMO base station radio device 100a according to this disclosure. In the second and subsequent embodiments, a case in which the distributed MIMO base station radio device provides a wireless communication environment by distributed MIMO to a communication terminal will be described as an example. However, this disclosure is applicable to base stations other than distributed MIMO in which the base station master and the base station slave are configured separately. [2-1: Configuration of Distributed MIMO Base Station Radio Device 100a]

[0020] 2 is a block diagram showing a configuration of a distributed MIMO base station radio device 100a according to this disclosure. As shown in FIG. 2, the distributed MIMO base station radio device 100a includes a mixed signal calculation device 110 as a base station master device and a distributed antenna 120 as a base station slave device.

[0021] The mixed signal processing device 110 receives communication information through a fronthaul connection of an O-RAN (Open Radio Access Networks), converts the information into an analog communication signal, and inputs and outputs the information. The mixed signal processing device 110 includes a clock 111 and a signal processing unit 112. The clock 111 performs precise time synchronization with a reference time such as the International Atomic Time by utilizing a Global Navigation Satellite System (GNSS), a Precision Time Protocol (PTP), or an atomic clock. The signal processing unit 112 generates a first analog communication signal based on communication data of a User Plane (U-Plane) and a Control Plane (C-Plane) obtained through the fronthaul, and transmits the first analog communication signal to the distributed antenna 120. When the signal processing unit 112 generates the first analog communication signal, the mixed signal processing device 110 records the rising (or falling) time of the analog communication signal as a first transmission / reception switching time. That is, the mixed signal calculation device 110 records the time when the transmission and reception of the analog communication signal is switched as the first transmission and reception switch time.

[0022] The distributed antenna 120 receives the analog communication signal output from the mixed signal arithmetic device 110 and performs wireless communication with a communication terminal. The distributed antenna 120 includes a directional coupler 121, an analog front end 122, a power meter 123, a microprocessor 124, and a clock 125.

[0023] The directional coupler 121 splits the analog communication signal sent from the mixed signal calculation device 110 into two signals. Specifically, the directional coupler 121 splits the first analog communication signal input to the distributed antenna 120 into a second analog communication signal and a third analog communication signal.

[0024] The analog front end 122 amplifies the first output signal of the directional coupler 121 and transmits radio waves. That is, the analog front end 122 receives the second analog communication signal, performs frequency conversion and amplification, and outputs radio waves.

[0025] The power meter 123 measures the power of the second output signal of the directional coupler 121. That is, the power meter 123 receives the third analog communication signal and outputs a voltage proportional to the signal power of the third analog communication signal.

[0026] The microprocessor 124 observes the output of the power meter 123. Based on the measurement result of the power meter 123, the microprocessor 124 records the time when the transmission and reception of the analog communication signal is switched as a second transmission and reception switching time.

[0027] The clock 125 provides time information to the microprocessor 124. The clock 125 performs precise time synchronization with a reference time using GNSS, PTP, or an atomic clock. The microprocessor 124 combines the output of the power meter 123 with the time information obtained from the clock 125, and records the time when the third analog communication power exceeds (or falls below) a predetermined threshold as the second transmission / reception switching time.

[0028] The microprocessor 124 notifies the mixed signal calculation device 110 of the second transmission / reception switching time. The mixed signal calculation device 110 calculates a value obtained by subtracting the first transmission / reception switching time as the first time from the second transmission / reception switching time as the second time as the analog communication signal propagation time. The mixed signal calculation device 110 adds the analog communication signal propagation time to a part of a delay parameter managed by O-RAN. The mixed signal calculation device 110 may add the analog communication signal propagation time to a delay parameter of an M-Plane (Management Plane). It can be understood that the operation of the calculation unit 11 and the operation of the correction unit 12 realized in the base station radio device 100 in the first embodiment are realized by the mixed signal calculation device 110.

[0029] With the above configuration, distributed MIMO base station radio apparatus 100a can create a communication schedule that takes into account the signal propagation time between mixed signal calculation apparatus 110 and distributed antenna 120, thereby enabling synchronization between base stations.

[0030] When the clock 125 is time-synchronized by PTP, the clock 125 and the mixed signal arithmetic device 110 may be connected via a communication line to perform time synchronization. However, since the purpose of this time synchronization is to synchronize with a reference time, the clock 125 may synchronize with a device other than the mixed signal arithmetic device 110 as long as it is a PTP network device. There is no problem with operation even if the clock 125 synchronizes with a device other than the mixed signal arithmetic device 110. [2-2: Time difference between signals in distributed MIMO base station radio device 100a]

[0031] 3 illustrates a time difference between the first analog communication signal output by the signal processing unit 112, the first analog communication signal input to the distributed antenna 120, and the signal observed by the microprocessor 124. As illustrated in FIG. 3, there is a delay time from the actual rise (or fall) of the first analog communication signal input to the distributed antenna 120 until the microprocessor 124 detects the rise (or fall) of the signal. The delay time until the signal is detected is a fixed value determined by the design of the distributed antenna 120. Therefore, a design value or an actual measurement value can be stored in the microprocessor 124 in advance and used when calculating the second transmission / reception switching time. Specifically, the time obtained by going back by the detection delay time from the time of the rise (or fall) of the output signal of the power meter 123 detected by the microprocessor 124 is set as the second transmission / reception switching time. [2-3: Delay parameters managed by O-RAN]

[0032] Figure 4 shows a conceptual diagram of delay parameters managed by O-RAN. A base station controller consisting of a CU (Central Unit) and a DU (Distributed Unit) manages the time to switch between transmitting and receiving wireless communication and determines the communication frame configuration. Therefore, if the base station controller does not know the total signal processing delay time beyond the DU shown in Figure 4, it cannot accurately manage the time to switch between transmitting and receiving wireless signals output from the antenna.

[0033] The two types of delay parameters used in M-Plane are effective as delay parameters that are corrected based on the analog communication signal propagation time. One is a parameter that adjusts the external antenna propagation delay, and the other is a parameter that adjusts the RU (Radio Unit) signal processing delay. The analog communication signal propagation time is added to one of the adjustment parameters.

[0034] The external antenna propagation delay adjustment parameter is a parameter that assumes the time required for a signal to propagate from the analog front end to the antenna end. The RU signal processing delay adjustment parameter is a parameter for inputting the time required for C / U-Plane signal processing in the base station radio equipment, and the signal processing times of signal processing unit 112 and analog front end 122 are input in advance. The RU signal processing delay adjustment parameter is defined separately for the downlink and uplink, and it is necessary to add the analog communication signal propagation time to both the downlink and uplink.

[0035] The O-RAN standard stipulates that the delay parameters of the M-Plane are output from the distributed MIMO base station radio apparatus 100a to the DU in response to a request from the DU. As a result, the delay parameters of the C / U-Plane communication data that the distributed MIMO base station radio apparatus 100a obtains through the fronthaul are corrected so that the communication schedule of the C / U-Plane communication data can be synchronized with that of other base station radio apparatuses. Therefore, with the above configuration, the distributed MIMO base station radio apparatus 100a can synchronize the communication schedule and prevent radio interference with other base station radio apparatuses.

[0036] The O-RAN standard is published on the O-RAN Alliance website, and the delay parameters are described in the WG4: Open Fronthaul Interfaces Workgroup documents O-RAN.WG4.CUS.0-R003-v11.00 and O-RAN.WG4.MP.0-R003-v11.00. Delay parameters that are adjusted within the O-RAN standard include T2a, Ta3, Tda, and Tau.

[0037] The delay parameter corrected based on the analog communication signal propagation time may be a delay parameter representing a fronthaul propagation delay between the DU and the mixed signal calculation device 110. It may also be a delay parameter representing a DU signal processing delay. Radio interference with other base station radio devices can also be prevented by adding the analog communication signal propagation time to these delay parameters.

[0038] The distributed MIMO base station radio apparatus 100a of the present disclosure can also finely adjust the time corresponding to the RU signal processing delay in response to a request from the DU. This can be achieved by temporarily storing and delaying the communication data of the C / U-Plane received by the distributed MIMO base station radio apparatus 100a for an arbitrary period of time before performing signal processing.

[0039] When implementing the distributed MIMO base station radio apparatus 100a of the present disclosure, a low-pass filter or a hysteresis comparator may be inserted between the power meter 123 and the microprocessor 124. These modifications are expected to increase the stability of the circuit operation.

[0040] 2 illustrates an example in which the power of the first analog communication signal is monitored by placing the directional coupler 121 and the power meter 123 in front of the analog front end 122. However, the directional coupler 121 and the power meter 123 may be placed inside the analog front end 122 to monitor the power. Also, the power of the signal output from the analog front end 122 may be monitored. Since it is sufficient for the directional coupler 121 and the power meter 123 to monitor the power of the analog communication signal flowing in the direction from the signal processing unit 112 to the analog front end 122, their placement can be changed on the signal propagation path. [3: Third embodiment]

[0041] A base station radio device, an information processing method, and a computer program according to a third embodiment will be described. In the following, a base station radio device, an information processing method, and a computer program according to a third embodiment will be described using a distributed MIMO base station radio device 100b according to this disclosure. [3-1: Configuration of distributed MIMO base station radio device 100b]

[0042] 5 is a block diagram showing a configuration of a distributed MIMO base station radio apparatus 100b according to this disclosure. As shown in FIG. 5, the distributed MIMO base station radio apparatus 100b includes a mixed signal calculation device 210 and a distributed antenna 220.

[0043] The mixed signal calculation device 210 includes a clock 211, a downlink signal processing unit 212, and an uplink signal processing unit 213. The clock 211 performs precise time synchronization with a reference time such as the International Atomic Time by utilizing GNSS, PTP, or an atomic clock. The mixed signal calculation device 210 obtains communication data of the U-Plane and C-Plane through the fronthaul. The downlink signal processing unit 212 generates an analog communication signal based on the communication data of the U-Plane and C-Plane. The mixed signal calculation device 210 transmits the generated analog communication signal to the distributed antenna 220.

[0044] The distributed antenna 220 includes a four-port switch 221, an analog front-end 222, and a microprocessor 223. The analog front-end 222 has a downlink signal input terminal and an uplink signal output terminal. An analog communication signal input to the distributed antenna 220 is input to a first port of the four-port switch 221. A second port of the four-port switch 221 is connected to a downlink signal input terminal of the analog front-end 222. A fourth port of the four-port switch 221 is connected to an uplink signal output terminal of the analog front-end 222. A third port of the four-port switch 221 is connected to the outside of the distributed antenna 220 and is connected to an uplink signal processing unit 213 of the mixed signal calculation device 210.

[0045] The analog front-end 222 performs at least one of frequency conversion, phase conversion, and gain adjustment on the signal output from the second port of the 4-port switch 221, and outputs the result as a radio wave. The analog front-end 222 also performs at least one of frequency conversion, phase conversion, and gain adjustment on the received radio wave, and outputs the result to the fourth port of the 4-port switch 221. [3-2: Operation of 4-port switch 221]

[0046] 6 shows the operation of the 4-port switch 221. The 4-port switch 221 can be in two types of operation states. In a first operation state 221a, the first port and the second port are connected, the third port and the fourth port are connected, and the other port combinations are released. In a second operation state 221b, the first port and the third port are connected, and the other port combinations are released. The 4-port switch 221 and the microprocessor 223 switch between the first operation state 221a and the second operation state 221b. The microprocessor 223 switches the connection of the 4-port switch 221 in response to an instruction from the mixed signal arithmetic device 210.

[0047] The distributed MIMO base station radio device 100b can be in an operation state in which normal wireless communication is performed with a user terminal, and an operation state in which a signal propagation time between the mixed signal arithmetic device 210 and the distributed antenna 220 is measured. When the distributed MIMO base station radio device 100b is performing normal wireless communication with a user terminal, the 4-port switch 221 is in a first operation state 221a. As a result, the downlink signal processing unit 212 and the uplink signal processing unit 213 are each connected to the analog front end 222 via the 4-port switch 221. On the other hand, when the distributed MIMO base station radio device 100b measures the signal propagation time between the mixed signal arithmetic device 210 and the distributed antenna 220, the 4-port switch 221 is in a second operation state 221b. As a result, the downlink signal processing unit 212 is connected to the uplink signal processing unit 213 via the 4-port switch 221. [3-3: Operation of measuring communication signal propagation time by distributed MIMO base station radio device 100b]

[0048] 7, a description will be given of an operation of the distributed MIMO base station radio apparatus 100b when measuring an analog communication signal propagation time between the mixed signal arithmetic device 210 and the distributed antenna 220. When measuring a signal propagation time between the mixed signal arithmetic device 210 and the distributed antenna 220, the distributed MIMO base station radio apparatus 100b transmits and receives calibration data between the mixed signal arithmetic device 210 and the distributed antenna 220.

[0049] When the downlink signal processing unit 212 converts the data for calibration into an analog communication signal, the mixed signal processing device 210 records the start time of the conversion process as a third time. Similarly, when the uplink signal processing unit 213 converts the received analog communication signal into data for calibration, the mixed signal processing device 210 records the end time of the conversion process as a fourth time. As a result, the elapsed time can be calculated by subtracting the third time from the fourth time. The elapsed time includes the processing time of the downlink signal and the processing time of the uplink signal. The processing time of the downlink signal and the processing time of the uplink signal are determined when the mixed signal processing device 210 is designed, so the numerical values ​​are known in advance. Therefore, the round-trip signal propagation time between the mixed signal processing device 210 and the distributed antenna 220 can be calculated by subtracting the processing time of the downlink signal and the processing time of the uplink signal from the elapsed time. Since it can be assumed that the signal propagation time is the same on the outbound and return routes, the one-way signal propagation time is calculated by calculating half of the round-trip signal propagation time. This one-way signal propagation time corresponds to the analog communication signal propagation time described in the second embodiment.

[0050] The analog communication signal propagation time calculated in the third embodiment is processed as a part of the delay parameters managed by O-RAN, as in the second embodiment. As a result, the C / U-Plane communication data received by the distributed MIMO base station radio device 100b through the fronthaul becomes communication data in which the delay parameters have been corrected so that the communication schedule can be synchronized with that of other base station radio devices. Therefore, with the above configuration, the distributed MIMO base station radio device 100b can perform time synchronization and prevent radio interference with other base station radio devices.

[0051] The distributed MIMO base station radio device 100b of the present disclosure can also fine-tune the time corresponding to the RU signal processing delay in response to a request from the DU. The fine-tuning can be realized by temporarily storing and delaying the communication data of the C / U-Plane received by the distributed MIMO base station radio device 100b for an arbitrary time period before performing signal processing. [4: Fourth embodiment]

[0052] A fourth embodiment of a base station radio device, an information processing method, and a computer program will be described. Hereinafter, a fourth embodiment of a base station radio device, an information processing method, and a computer program will be described using a distributed MIMO base station radio device 100c according to this disclosure. [4-1: Configuration of distributed MIMO base station radio device 100c]

[0053] FIG. 8 is a block diagram showing a configuration of a distributed MIMO base station radio apparatus 100c according to this disclosure. The distributed MIMO base station radio apparatus 100c includes a mixed signal calculation device 210, a distributed antenna 220, and an RoF device 230. The distributed MIMO base station radio apparatus 100c differs from the distributed MIMO base station radio apparatus 100b in that the analog communication signal is propagated by RoF (Radio over Fiber). Other features of the distributed MIMO base station radio apparatus 100c may be the same as other features of the distributed MIMO base station radio apparatus 100b. Therefore, in the following, only the parts that differ from the embodiments already described will be described in detail, and the description of other overlapping parts will be omitted as appropriate. [4-2: Internal structure of RoF device 230]

[0054] FIG. 9 shows an example of the internal structure of the RoF device 230. The RoF device 230 has a first electrical-optical converter 231, a first optical-electrical converter 232, a second electrical-optical converter 233, a second optical-electrical converter 234, a first wavelength filter 235, and a second wavelength filter 236. An analog communication signal output from the downlink signal processing unit 212 is input to the first electrical-optical converter 231 and converted from an electrical signal to an optical signal of a first wavelength. The optical signal of the first wavelength output from the first electrical-optical converter 231 is input to the first wavelength filter 235 and multiplexed with optical signals of other wavelengths. The optical signal of the first wavelength multiplexed with optical signals of other wavelengths by the first wavelength filter 235 is output to the second wavelength filter 236 through an optical fiber. The second wavelength filter 236 extracts the optical signal of the first wavelength and outputs it to the first optical-electrical converter 232. The first optical-electrical converter 232 converts the input optical signal of the first wavelength into an electrical signal and outputs it to the first port of the four-port switch 221. The electrical signal output from the third port of the four-port switch 221 is input to the second electrical-optical converter 233 and converted into an optical signal of the second wavelength. The optical signal of the second wavelength output from the second electrical-optical converter 233 is input to the second wavelength filter 236 and multiplexed with optical signals of other wavelengths. The optical signal of the second wavelength multiplexed with optical signals of other wavelengths by the second wavelength filter 236 is output to the first wavelength filter 235 through the optical fiber. The first wavelength filter 235 extracts the optical signal of the second wavelength and outputs it to the second optical-electrical converter 234. The second optical-electrical converter 234 converts the input optical signal of the second wavelength into an electrical signal and outputs it to the uplink signal processing unit 213. [5: Fifth embodiment]

[0055] A fifth embodiment of a base station radio device, an information processing method, and a computer program will be described. Hereinafter, a fifth embodiment of a base station radio device, an information processing method, and a computer program will be described using a distributed MIMO base station radio device 100d according to this disclosure. [5-1: Configuration of distributed MIMO base station radio device 100d]

[0056] Fig. 10 is a block diagram showing a configuration of a distributed MIMO base station radio apparatus 100d according to this disclosure. As shown in Fig. 10, the distributed MIMO base station radio apparatus 100d may have n (n is a natural number of 2 or more) distributed antennas 320 connected to one mixed signal arithmetic device 310. The distributed MIMO base station radio apparatus 100d described in the fifth embodiment has a mixed signal arithmetic device 310 having a clock 311 and a first signal processing unit 312-1 to an n-th signal processing unit 312-n, and a first distributed antenna 320-1 to an n-th distributed antenna 320-n.

[0057] The k-th distributed antenna 320-k (k is a natural number between 1 and n) and the k-th signal processor 312-k shown in Fig. 10 can be replaced with the distributed antenna 120 and the signal processor 112 shown in Fig. 2. In the fifth embodiment, the analog communication signal propagation time is calculated by the method described in the second embodiment. That is, the k-th distributed antenna 320-k returns the time when it received the analog communication signal to the mixed signal arithmetic device 310, and calculates the analog communication signal propagation time between them by comparing the time when the mixed signal arithmetic device 310 transmitted the analog communication signal.

[0058] Similarly, the k-th distributed antenna 320-k shown in FIG. 10 can be replaced with the distributed antenna 220 shown in FIG. 5 and FIG. 8, and the k-th signal processor 312-k can be replaced with a combination of the downlink signal processor 212 and the uplink signal processor 213. In this configuration, the k-th distributed antenna 320-k switches between an operation state in which normal wireless communication is performed with a user terminal and an operation state in which the analog communication signal propagation time between the mixed signal processor 310 and the k-th distributed antenna 320-k is measured according to the procedure described in the third and fourth embodiments. That is, as shown in FIG. 7, the one-way analog communication signal propagation time is calculated from the time it takes to travel back and forth between the mixed signal processor 310 and the k-th distributed antenna 320-k.

[0059] Fig. 11 illustrates a method for synchronizing the timing of outputting radio waves from the distributed antennas 320 of the distributed MIMO base station radio apparatus 100d of the fifth embodiment. The analog communication signal propagation time between the mixed signal calculation apparatus 310 and the k-th distributed antenna 320-k is referred to as the k-th signal propagation time. The distributed MIMO base station radio apparatus 100d calculates the analog communication signal propagation time for each of the n distributed antennas, and obtains a different value for each. Fig. 11 illustrates a case in which the analog communication signal propagation time of the p-th distributed antenna 320-p (p is a natural number between 1 and n) is the longest.

[0060] As described in the second embodiment, the distributed MIMO base station radio device 100d synchronizes with other base stations by adding the analog communication signal propagation time to a part of the delay parameter managed by O-RAN. The distributed MIMO base station radio device 100d has n types of analog communication signal propagation times, and adds the longest p-th signal propagation time among them to a part of the delay parameter managed by O-RAN. The other q-th signal propagation times (q is a natural number between 1 and n, and q is a value different from p) are shorter than the p-th signal propagation time, so correction is required to align the timing of radio wave emission from the distributed antennas. The mixed signal calculation device 310 performs this correction. As shown in FIG. 11, when generating an analog communication signal to be sent to the q-th distributed antenna 320-q, the mixed signal calculation device 310 temporarily stores the C / U-Plane signal received from the fronthaul, delays it by the correction time, and then starts generating the analog communication signal in the q-th signal processing unit 312-q. The correction time corresponds to the difference between the pth signal propagation time and the qth signal propagation time.

[0061] As shown in FIG. 12, the base station radio apparatus 100 according to the present disclosure (and each of the distributed MIMO base station radio apparatuses 100a to 100d) may include an information processing apparatus 1001 and a storage apparatus 1002.

[0062] The information processing device 1001 may include at least one of a central processing unit (CPU), a graphic processing unit (GPU), and a field programmable gate array (FPGA). The information processing device 1001 may read a computer program. For example, the information processing device 1001 may read a computer program stored in a storage device 1002. For example, the information processing device 1001 may read a computer program stored in a computer-readable storage medium using a storage medium reading device (not shown). The information processing device 1001 may acquire (i.e., download or read) a computer program from a device (not shown) disposed outside the base station radio device 100 via a communication device (not shown). The information processing device 1001 executes the read computer program. As a result, a logical function block for executing the operation to be performed by the base station radio device 100 is realized in the information processing device 1001. Specifically, a logical function block for executing the above-mentioned information processing operation is realized in the information processing device 1001. In other words, the information processing device 1001 can function as a controller for implementing logical functional blocks for executing the operations that the base station radio device 100 should perform.

[0063] The storage device 1002 can store desired data. For example, the storage device 1002 may temporarily store a computer program executed by the information processing device 1001. The storage device 1002 may temporarily store data that is temporarily used by the information processing device 1001 when the information processing device 1001 is executing a computer program. The storage device 1002 may store data that the base station radio device 100 stores for a long period of time. The storage device 1002 may include at least one of a RAM (Random Access Memory), a ROM (Read Only Memory), a hard disk device, a magneto-optical disk device, an SSD (Solid State Drive), and a disk array device. [6: Notes]

[0064] The following supplementary notes are further disclosed regarding the above-described embodiment. [Appendix 1] a calculation means for calculating a value representing a propagation time of an analog communication signal propagating between the base station slave unit and the base station master unit, based on an output time of a downlink signal output in an analog manner from a base station master unit included in a base station radio device to the base station slave unit included in the base station radio device, and an input time of the downlink signal input to the base station slave unit; a correction means for correcting a parameter representing a signal delay time within said base station radio equipment based on a value representing a propagation time of said analog communication signal; A base station radio device comprising: [Appendix 2] The base station radio device operates in accordance with the corrected parameters. 2. A base station radio device as claimed in claim 1. [Appendix 3] The base station radio device provides a wireless communication environment using distributed MIMO (Multiple Input Multiple Output) to the communication terminal. 2. A base station radio device as claimed in claim 1. [Appendix 4] The base station master unit includes: a first clock that is synchronized with a reference time; a signal processing unit that outputs the downlink signal; 4. A base station radio device as claimed in claim 3. [Appendix 5] The signals communicated by the base station radio equipment adopt a time division duplex system, The base station slave unit includes: a directional coupler that divides the input downlink signal into a first distribution signal and a second distribution signal; an analog front end that amplifies the first distribution signal and outputs a radio wave; a power meter that detects the power of the second distribution signal and outputs an output signal; a microprocessor that monitors the output signal of the power meter; a second clock that is synchronized with a reference time and provides time to the microprocessor; the base station master records a rise or fall time of the downlink signal output by the signal processing unit as a first time; the microprocessor records a rise or fall time of the output signal of the power meter as a second time; The calculation means calculates the difference between the second time and the first time as the propagation time of the analog communication signal. 5. A base station radio device as claimed in claim 4. [Appendix 6] The base station master unit includes: The signal processing unit includes a downlink signal processing unit that performs transmission processing of the downlink signal, and an uplink signal processing unit that performs reception processing of an uplink signal, The base station slave unit includes: an analog front end for transmitting and / or receiving wireless communication signals; a 4-port switch, a first port of which is connected to the downlink signal processing unit, a second port of which is connected to a transmission port of the analog front-end, a third port of which is connected to the uplink signal processing unit, and a fourth port of which is connected to a reception port of the analog front-end; A microprocessor that switches the operation of the 4-port switch according to an instruction from the base station master unit; when communicating with the communication terminal, connecting the first port and the second port of the 4-port switch, connecting the third port and the fourth port of the 4-port switch, and isolating other combinations; When measuring the propagation time of the downlink signal, the first port and the third port of the 4-port switch are connected and other combinations are isolated; The calculation means calculates, as a propagation time of the analog communication signal, half of a difference between a third time when the uplink signal processing unit receives a downlink signal for calibration and a fourth time when the downlink signal processing unit transmits the downlink signal for calibration. 5. A base station radio device as claimed in claim 4. [Appendix 7] There are N base station slave units (N is a natural number of 2 or more), The base station master unit has N signal processing units, The N base station slave devices and the N signal processing units each have a signal line for one-to-one communication of downlink signals, Calculating the propagation time of one of the analog communication signals for each of the N base station slave units; Add the longest value of the propagation times of the analog communication signals calculated for each of the N base station slave units to the parameter; For the N-1 base station slave devices corresponding to the propagation time of the analog communication signal other than that added to the parameter, a downlink signal is generated by delaying the signal by a difference between the longest value in the base station master device and the propagation time of the analog communication signal of the base station slave device itself. 7. A base station radio device according to claim 4, [Appendix 8] a base station master unit included in a base station radio device calculates a propagation time of an analog communication signal propagating between the base station slave unit and the base station master unit based on an output time of a downlink signal output in an analog manner to the base station slave unit included in the base station radio device and an input time of the downlink signal input to the base station slave unit; A parameter representing a signal delay time in the base station radio equipment is corrected based on a value representing a propagation time of the analog communication signal. An information processing method comprising the steps of: [Appendix 9] a base station master unit included in a base station radio device calculates a propagation time of an analog communication signal propagating between the base station slave unit and the base station master unit based on an output time of a downlink signal output in an analog manner to the base station slave unit included in the base station radio device and an input time of the downlink signal input to the base station slave unit; A parameter representing a signal delay time in the base station radio equipment is corrected based on a value representing a propagation time of the analog communication signal. A computer program for causing a computer to operate in such a manner.

[0065] The present invention can be modified as appropriate within the scope that does not contradict the gist or idea of ​​the invention that can be read from the claims and the entire specification, and base station radio equipment, information processing methods, and computer programs that involve such modifications are also included in the technical idea of ​​the present invention. [Explanation of symbols]

[0066] 100 Base station radio equipment 100a,100b,100c,100d Distributed MIMO base station radio equipment 11 Calculation section 12 Correction section 110,210,310 Mixed signal processor 120,220,320 Distributed Antenna 121 Directional coupler 122,222 Analog Front End 123 Power measuring instrument 124,223 Microprocessors 111,125,211,311 Watches 112,312 Signal Processing Unit 212 Downlink signal processing section 213 Uplink signal processing section 221 4 port switch 230 RoF equipment 231 First electrical-optical converter 232 First optical-electrical converter 233 Second Electrical-Optical Converter 234 Second optical-electrical converter 235 First Wavelength Filter 236 Second Wavelength Filter

Claims

1. a calculation means for calculating a value representing a propagation time of an analog communication signal propagating between the base station slave unit and the base station master unit, based on an output time of a downlink signal output in an analog manner from a base station master unit included in a base station radio device to the base station slave unit included in the base station radio device, and an input time of the downlink signal input to the base station slave unit; a correction means for correcting a parameter representing a signal delay time within said base station radio equipment based on a value representing a propagation time of said analog communication signal; A base station radio device comprising:

2. The base station radio device operates in accordance with the corrected parameters.

2. A base station radio device according to claim 1.

3. The base station radio device provides a wireless communication environment using distributed multiple input multiple output (MIMO) to the communication terminal.

2. A base station radio device according to claim 1.

4. The base station master unit includes: a first clock that is synchronized with a reference time; a signal processing unit that outputs the downlink signal; 4. A base station radio device according to claim 3.

5. The base station radio equipment communicates signals using a time division duplex system, The base station slave unit includes: a directional coupler that divides the input downlink signal into a first distribution signal and a second distribution signal; an analog front end that amplifies the first distribution signal and outputs a radio wave; a power meter that detects the power of the second distribution signal and outputs an output signal; a microprocessor that monitors the output signal of the power meter; a second clock that is synchronized with a reference time and provides time to the microprocessor; the base station master records a rise or fall time of the downlink signal output by the signal processing unit as a first time; the microprocessor records a rise or fall time of the output signal of the power meter as a second time; The calculation means calculates the difference between the second time and the first time as the propagation time of the analog communication signal.

5. A base station radio device according to claim 4.

6. The base station master unit includes: The signal processing unit includes a downlink signal processing unit that performs transmission processing of the downlink signal, and an uplink signal processing unit that performs reception processing of an uplink signal, The base station slave unit includes: an analog front end for transmitting and / or receiving wireless communication signals; a four-port switch, a first port of which is connected to the downlink signal processing unit, a second port of which is connected to a transmission port of the analog front-end, a third port of which is connected to the uplink signal processing unit, and a fourth port of which is connected to a reception port of the analog front-end; a microprocessor that switches the operation of the 4-port switch in accordance with an instruction from the base station master unit; when communicating with the communication terminal, connecting the first port and the second port of the 4-port switch, connecting the third port and the fourth port of the 4-port switch, and isolating other combinations; When measuring the propagation time of the downlink signal, the first port and the third port of the four-port switch are connected and other combinations are isolated; The calculation means calculates, as a propagation time of the analog communication signal, half of a difference between a third time when the uplink signal processing unit receives a downlink signal for calibration and a fourth time when the downlink signal processing unit transmits the downlink signal for calibration.

5. A base station radio device according to claim 4.

7. There are N base station slave units (N is a natural number of 2 or more), The base station master unit has N signal processing units, The N base station slave devices and the N signal processing units each have a signal line for one-to-one communication of a downlink signal, Calculating a propagation time of one of the analog communication signals for each of the N base station slave units; Adding the longest value of the propagation times of the analog communication signals calculated for each of the N base station slave units to the parameter; For the N-1 base station slave devices corresponding to the propagation time of the analog communication signal other than that added to the parameter, a downlink signal is generated by delaying the signal by a difference between the longest value in the base station master device and the propagation time of the analog communication signal of the base station slave device itself.

7. A base station radio apparatus according to claim 4, wherein the base station radio apparatus is a base station radio apparatus.

8. a base station master unit included in a base station radio device calculates a propagation time of an analog communication signal propagating between the base station slave unit and the base station master unit based on an output time of a downlink signal output in an analog manner to the base station slave unit included in the base station radio device and an input time of the downlink signal input to the base station slave unit; A parameter representing a signal delay time in the base station radio equipment is corrected based on a value representing a propagation time of the analog communication signal. An information processing method comprising the steps of:

9. a base station master unit included in a base station radio device calculates a propagation time of an analog communication signal propagating between the base station slave unit and the base station master unit based on an output time of a downlink signal output in an analog manner to the base station slave unit included in the base station radio device and an input time of the downlink signal input to the base station slave unit; A parameter representing a signal delay time in the base station radio equipment is corrected based on a value representing a propagation time of the analog communication signal. A computer program for causing a computer to operate in such a manner.

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