JP2015032997A - Base station device, control method of the same, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure highly precise time synchronization between a master eNB and a slave eNB.SOLUTION: A base station device receives a first radio signal transmitted from another base station device, transmits a second radio signal after first predetermined time is elapsed since the first radio signal is received, acquires from another base station device information on propagation delay in a radio segment between the base station device and another base station device which is calculated on the basis of timing at which the first radio signal is transmitted, timing at which the second radio signal is received, and the first predetermined time in another base station device, and performs control so as to be synchronized in time with another base station device, in accordance with information on the propagation delay and information on the transmission time included in the radio signal from another base station device.

Description

  The present invention relates to a technology in which a mobile communication device communicates with a plurality of base station devices.

  In the 3rd Generation Partnership Project (3GPP), installing many small cells (small cells) that use different frequency bands (for example, higher frequency bands than those used in macro cells) within the coverage of large cells (macro cells) Has been discussed. For example, as in the example of FIG. 1, a plurality of small cells using the 3.5 GHz band frequency band are placed in the coverage area of the macro cell using the 2 GHz band frequency band.

  In LTE Release 12, discussions have begun on a technology called Dual Connectivity in which two types of base stations cooperate in a layer higher than the MAC (medium access control) layer in such an environment. Here, the two types of base stations are a master eNB (for example, a macro base station) and a slave eNB (for example, a small cell base station), where the master eNB leads communication control, and the slave eNB controls communication control. Operates based on. In Dual Connectivity, two types of base stations are connected by a wired or wireless backhaul line, and for example, traffic transmitted to a terminal is passed to a slave eNB via a master eNB. The passed signal is then transmitted as a radio signal from the slave eNB to the terminal. Moreover, the signal transmitted from the terminal to the slave eNB is transferred from the slave eNB to the master eNB. That is, all or most of the traffic passes through the master eNB once.

  Here, the backhaul line is required to have a large capacity such as 1 Gbps, for example, while the request for the delay is not relatively severe such as 10 msec or more. Therefore, as shown in FIG. 2, in dual connectivity, control data (C-plane) for maintaining mobility and data with high real-time properties such as voice call traffic are transmitted from the master eNB to the terminal. On the other hand, best-effort user data (U-plane) that does not require real-time performance such as Web browsing is transmitted from the slave eNB to the terminal. Thereby, it is possible to perform data offloading to the slave eNB without performing handover associated with connection to the slave eNB.

NTT DOCOMO, R1-132679, “Views on radio-IF based synchronization mechanisms”, 3GPP TSG RAN WG1 # 73, May 2013

  When the master eNB and the slave eNB perform advanced cooperation, high-accuracy time synchronization may be required. Here, in order to realize highly accurate time synchronization, time synchronization using GPS is widely used. However, since the location of the small cell base station is not limited to the outdoors, the GPS cannot always be used. In contrast, 3GPP discusses a method of time synchronization using a radio interface. For example, Non-Patent Document 1 proposes a method for realizing time synchronization by allowing a small cell base station to receive a downlink signal transmitted from a macro base station. However, this method has a problem that high-accuracy time synchronization including propagation delay is not easy.

  The present invention has been made in view of the above problems, and an object of the present invention is to ensure highly accurate time synchronization between a master eNB and a slave eNB.

  In order to achieve the above object, a base station apparatus according to the present invention includes a receiving means for receiving a first radio signal transmitted from another base station apparatus, and a first unit after receiving the first radio signal. A transmission means for transmitting a second radio signal after a predetermined time has elapsed; a timing at which the other base station apparatus transmits the first radio signal; a timing at which the second radio signal is received; Acquisition means for acquiring, from the other base station device, information on a propagation delay in a radio section between the base station device and the other base station device calculated based on a predetermined time of 1; Control means for controlling the base station apparatus so as to be time-synchronized with the other base station apparatus based on delay information.

  In order to achieve the above object, another base station apparatus according to the present invention includes: a transmitting unit that transmits a first radio signal; and the other base station apparatus, wherein the other base station apparatus is connected to the first base station apparatus. Receiving means for receiving a second radio signal to be transmitted after a predetermined time has elapsed since receiving the radio signal; timing for transmitting the first radio signal; timing for receiving the second radio signal; Calculating means for calculating a propagation delay of a radio section between the base station apparatus and the other base station apparatus based on the predetermined time, and transmitting the propagation delay information to the other base station apparatus And the other base station apparatus is controlled to be time-synchronized with the base station apparatus based on the propagation delay information.

  According to the present invention, highly accurate time synchronization can be ensured between a master eNB and a slave eNB.

The conceptual diagram which shows the example of arrangement | positioning of the macro cell and small cell which each use a different frequency band. The conceptual diagram which shows the example of communication between the terminal and multiple eNB by Dual Connectivity. The figure which shows the hardware structural example of a master eNB, a slave eNB, and a terminal. The block diagram which shows the function structural example of the master eNB. The block diagram which shows the function structural example of a slave eNB. The sequence chart which shows the operation example of a master eNB and a slave eNB.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

(System configuration)
The radio communication system according to the present embodiment includes, for example, a master eNB, a slave eNB, and a terminal as illustrated in FIG. Here, eNB is a base station apparatus, but the corresponding wireless communication system may be other than LTE. The terminal is a mobile unit or a fixed radio communication device, and may correspond to a radio communication system other than LTE. In the wireless communication system of the present embodiment, the master eNB performs communication using a first frequency band (for example, 2 GHz), and the slave eNB performs communication using a second frequency band (3.5 GHz). However, even if the master eNB and the slave eNB use the same frequency band, the following discussion is valid.

  In the present embodiment, the master eNB and the slave eNB are connected to each other via a wired or wireless communication line (backhaul line). Then, the master eNB and the slave eNB, for example, cooperate to transmit a downlink signal to the terminal at the same timing. At this time, highly accurate time synchronization may be required between the master eNB and the slave eNB. By ensuring highly accurate time synchronization, for example, signals from the master eNB and the slave eNB arrive with delay waves in a range not exceeding the guard interval (GI). For this reason, transmission data from the master eNB and the slave eNB can be simultaneously extracted by one FFT process.

  In this embodiment, in order to ensure such highly accurate time synchronization, the slave eNB receives the first radio signal from the master eNB. Here, the first radio signal may not be addressed to the slave eNB, and the slave eNB may intercept the radio signal transmitted to the terminal. Then, the slave eNB transmits the second radio signal to the master eNB after a predetermined time has elapsed after receiving the first radio signal. When the master eNB receives the second radio signal, based on the timing at which the first radio signal is transmitted, the timing at which the second radio signal is received, and the predetermined time described above, the master eNB and the slave eNB The propagation delay of the wireless section between is calculated. Thereafter, the master eNB notifies the slave eNB of the propagation delay using, for example, the X2 interface.

  Thereafter, the slave eNB performs time synchronization control with the master eNB using the notified propagation delay. Specifically, the slave eNB receives, for example, a radio signal from the master eNB including the transmission time, and the time obtained by subtracting the propagation delay from the reception time at the slave eNB and the transmission included in the radio signal The internal clock is controlled so that the time matches. Or slave eNB controls the timing which transmits a signal according to the timing which subtracted the propagation delay from the reception timing of the radio signal from master eNB. That is, the slave eNB acquires the transmission timing of the radio signal in the master eNB by subtracting the propagation delay from the reception timing of the radio signal, and transmits the radio signal in accordance with the transmission timing, Time synchronization. This process may be repeatedly executed a plurality of times.

  Thus, in this embodiment, the propagation delay between the master eNB and the slave eNB is calculated, and the slave eNB ensures time synchronization with the master eNB according to the result. According to this, since it becomes possible for the slave eNB to establish time synchronization based on the timing at which the master eNB actually transmits a signal, highly accurate time synchronization between the master eNB and the slave eNB is ensured. It becomes possible.

  Hereinafter, configurations and operations of the master eNB and the slave eNB will be described in detail.

(Base station and terminal hardware configuration)
FIG. 3 is a diagram illustrating a hardware configuration example of the master eNB and the slave eNB. For example, the master eNB and the slave eNB have the same hardware configuration as illustrated in FIG. 3, and include, for example, a CPU 301, a ROM 302, a RAM 303, an external storage device 304, and a communication device 305. In the master eNB and the slave eNB, for example, a program that realizes each function of the master eNB and the slave eNB shown below, which is recorded in any of the ROM 302, the RAM 303, and the external storage device 304, is executed by the CPU 301. Then, the master eNB and the slave eNB use the communication device 305 to perform communication between the master eNB or slave eNB and the terminal, or inter-eNB communication between the master eNB and the slave eNB. In FIG. 3, the master eNB and the slave eNB have one communication device 305. However, for example, a communication device for communication between eNBs and a communication device with a terminal may be included.

  Note that the master eNB and the slave eNB may be provided with dedicated hardware that executes each function described below, or a part that is executed by the hardware and the other part is executed by a computer that operates the program. May be. Further, all the following functions may be executed by a computer and a program.

(Functional configuration of master eNB)
FIG. 4 is a block diagram illustrating a functional configuration example of the master eNB. The master eNB includes, for example, a wireless communication unit 401, a wired communication unit 402, and a propagation delay calculation unit 403.

  The wireless communication unit 401 is a functional unit that transmits wireless signals and receives wireless signals transmitted from other wireless communication devices. In the present embodiment, the radio communication unit 401 transmits, for example, a first radio signal (for example, a synchronization signal) received by the terminal and the slave eNB, and a second radio signal (for example, the master eNB) transmitted by the slave eNB. PRACH using a sequence designated by the user is received. Then, the wireless communication unit 401 notifies the propagation delay calculation unit 403 of the timing at which the first wireless signal is transmitted and the timing at which the second wireless signal is received, for example. Note that the propagation delay calculation unit 403 may acquire the timing at which the first radio signal is transmitted and the timing at which the second radio signal is received by monitoring the radio communication unit 401.

  The wired communication unit 402 is a functional unit that performs wired communication with another base station device via, for example, an X2 interface. In the present embodiment, the wired communication unit 402 performs wired communication with the slave eNB, and transmits, for example, information specifying a sequence to be used for transmission of the second radio signal. In this case, when a wireless signal using the specified sequence is received, the wireless communication unit 401 determines that the wireless signal is the second wireless signal, and calculates the propagation delay of the timing at which the wireless signal is received. Notification to the unit 403. On the other hand, since the wireless signal that does not use the designated sequence is not the second wireless signal, the wireless communication unit 401 can ignore the wireless signal even if the wireless signal is received. Note that the second radio signal may be a predetermined signal, and in this case, the wired communication unit 402 may not notify the slave eNB of information related to the second radio signal.

  Further, the wired communication unit 402 may notify the slave eNB of what kind of signal the first wireless signal is (for example, a synchronization signal) before transmitting the first wireless signal. Further, the wired communication unit 402 may notify the slave eNB of information related to the timing at which the first radio signal is transmitted before the transmission of the first radio signal.

  The propagation delay calculation unit 403 is configured to transmit the first radio signal, the reception timing of the second radio signal, and the predetermined time until the slave eNB transmits the second radio signal after receiving the first radio signal. Based on the time, the propagation delay of the radio section to the slave eNB is calculated. Specifically, the propagation delay calculation unit 403 sets the propagation delay z to z = (y, where t is the transmission timing of the first radio signal, y is the reception timing of the second radio signal, and x is the predetermined time. -T-x) / 2.

(Functional configuration of slave eNB)
FIG. 5 is a block diagram illustrating a functional configuration example of the slave eNB. The slave eNB includes, for example, a wireless communication unit 501, a wired communication unit 502, and a time synchronization control unit 503.

  The wireless communication unit 501 is a functional unit that transmits a wireless signal and receives a wireless signal transmitted from another wireless communication device. In the present embodiment, the radio communication unit 501 has the ability to receive the downlink signal of the master eNB and the ability to transmit the uplink signal that can be received by the master eNB.

  The radio communication unit 501 receives, for example, a first radio signal (for example, a synchronization signal, a common reference signal) transmitted from the master eNB, and a second radio signal (for example, a sequence designated by the master eNB) received by the master eNB. PRACH using Then, for example, the radio communication unit 501 receives a radio signal including transmission time information from the master eNB, and notifies the time synchronization control unit 503 of the transmission time information and the reception time information of the radio signal. . Further, the radio communication unit 501 may notify the time synchronization control unit 503 of information on the reception timing of the radio signal from the master eNB.

  The wired communication unit 502 is a functional unit that performs wired communication with another base station device via, for example, an X2 interface. In the present embodiment, the wired communication unit 502 performs wired communication with the master eNB, and acquires, for example, information related to the propagation delay in the wireless section between the master eNB and the slave eNB. Information on the propagation delay is notified to the time synchronization control unit 503.

  Further, the wired communication unit 502 may acquire information specifying a sequence to be used for transmitting the second wireless signal. In this case, when information on a sequence to be used for transmission is acquired, the radio communication unit 501 generates a second radio signal using the sequence and transmits the second radio signal to the master eNB. Note that the second wireless signal may be a predetermined signal. In this case, the wired communication unit 502 may not acquire such series of information.

  In addition, the wired communication unit 502 indicates what kind of signal the first wireless signal is (for example, a synchronization signal or a common reference signal) before the first wireless signal is transmitted from the master eNB. Information may be acquired from the master eNB. In this case, the wireless communication unit 501 transmits the second wireless signal to the master eNB after a predetermined time has elapsed after receiving the wireless signal specified by the acquired information. That is, the notification of the information of the first radio signal enables the slave eNB to know what type of radio signal is the trigger for time synchronization control. Further, when the slave eNB receives a radio signal different from the notified information, the slave eNB can know that this signal is irrelevant to the time synchronization control.

  Further, the wired communication unit 502 may acquire information related to the timing at which the first radio signal is transmitted from the master eNB before the first radio signal is transmitted. In this case, when the wireless communication unit 501 receives the first wireless signal before the second predetermined time different from the predetermined time (first predetermined time) described above from the timing, the wireless communication unit 501 receives the first wireless signal. After the first predetermined time has elapsed from the timing, the second radio signal is transmitted. Note that the first predetermined time and the second predetermined time may be the same length. Thus, the slave eNB is notified of the transmission timing of the first radio signal, and the signal received after the second predetermined time has elapsed from the transmission timing is irrelevant to the time synchronization control. Can know. For example, when the synchronization signal or the common reference signal transmitted periodically is the first radio signal, the second predetermined time is set to a time length equal to or shorter than the period, and the synchronization is performed within the second predetermined time. The signal or common reference signal will be received only once. Therefore, the slave eNB can identify which signal is the first radio signal that triggers time synchronization control.

  The time synchronization control unit 503 controls the slave eNB so that the slave eNB is time synchronized with the master eNB based on the propagation delay notified from the master eNB.

  For example, when the time synchronization control unit 503 acquires from the wireless communication unit 501 the information on the transmission time included in the radio signal from the master eNB and the information on the reception time at the slave eNB that has received the radio signal. The internal clock is controlled based on the information and the propagation delay. Specifically, when time synchronization between the master eNB and the slave eNB is ensured, the time obtained by subtracting the propagation delay from the reception time based on the clock of the slave eNB matches the transmission time included in the radio signal. It should be. For this reason, the time synchronization control unit 503 sets the clock inside the slave eNB to the inside of the master eNB based on the time obtained by subtracting the propagation delay from the reception time of the radio signal and the transmission time included in the radio signal. Control to match the clock. For example, when the time obtained by subtracting the propagation delay from the reception time is M milliseconds earlier than the transmission time included in the radio signal, the time synchronization control unit 503 delays the internal clock of the slave eNB by M milliseconds. Similarly, for example, when the time obtained by subtracting the propagation delay from the reception time is N milliseconds later than the transmission time included in the radio signal, the time synchronization control unit 503 delays the internal clock of the slave eNB by N milliseconds. . Thus, by matching the clocks of the master eNB and the slave eNB, for example, a predetermined process (for example, transmission of a downlink signal) specifying a time is synchronized between the master eNB and the slave eNB. It becomes possible to execute.

  In addition, for example, when the time synchronization control unit 503 acquires information on the reception timing of the radio signal from the master eNB from the radio communication unit 501, the radio communication unit 501 according to the result of subtracting the propagation delay from the reception timing. Controls the timing of transmitting radio signals. That is, the time synchronization control unit 503 controls the timing at which the radio communication unit 501 transmits a radio signal to be synchronized with the timing at which the radio communication unit 401 of the master eNB transmits a radio signal. Specifically, the time synchronization control unit 503 controls the transmission timing so that the start timing of the frame of the transmission signal of the master eNB matches the start timing of the frame of the transmission signal of the slave eNB. In this case, the time synchronization control unit 503 can synchronize the signal transmission timing of the master eNB and the signal transmission timing of the slave eNB without adjusting the clock inside the slave eNB.

(Processes executed in the wireless communication system)
Then, the process performed between the master eNB and the slave eNB is demonstrated with reference to FIG. In FIG. 6, inter-eNB communication using the X2 interface is indicated by a dashed arrow between the master eNB and the slave eNB, and transmission of a radio signal between the master eNB and the slave eNB is indicated by a solid arrow. Indicates reception.

  As an initial state, it is assumed that the master eNB and the slave eNB have established rough synchronization using a radio signal such as a synchronization signal or a common reference signal by the master eNB (S601). For example, when the transmission time is included in these radio signals, the slave eNB performs coarse synchronization by adjusting the internal clock assuming that the time when the radio signal is received is the transmission time. It is possible to take. When a plurality of radio waves arrive due to reflection, diffraction, etc., the slave eNB may take coarse synchronization with reference to the radio wave that has arrived first among these radio waves. For example, the slave eNB can synchronize the reception timing of the frame (10 ms unit) and the subframe (1 ms unit) by using a primary synchronization signal (PSS) or a secondary synchronization signal (SSS).

  Thereafter, the master eNB and the slave eNB start adjustment of time synchronization. First, the master eNB notifies the slave eNB of at least one of information on the first radio signal and information on the second radio signal, for example, using the X2 interface (S603). For example, the master eNB notifies the slave eNB of what kind of signal the first radio signal used for time synchronization adjustment is (synchronization signal, common reference signal, etc.). If the slave eNB knows what kind of signal the first radio signal is, this notification may not be necessary. Moreover, the master eNB may notify the slave eNB of the transmission timing of the first radio signal. When the first radio signal is a common reference signal, information on which subframe is used as the first radio signal may be notified as information on transmission timing. In addition, the master eNB may notify the slave eNB of information (for example, information on a sequence to be used) regarding the second radio signal transmitted by the slave eNB. Note that, by storing a plurality of sequence candidates in advance in the slave eNB, the master eNB can notify specific information specifying one of them as information on a sequence to be used. For example, when the slave eNB knows information on a sequence to be used for the second radio signal, this information may not be notified.

  Thereafter, the master eNB transmits the first radio signal, and the slave eNB receives the first radio signal (S604). At this time, the master eNB stores transmission time information t. Note that the first radio signal to be transmitted is, for example, a synchronization signal or a common reference signal. In this case, the master eNB does not transmit a radio signal for time synchronization, although it is not a signal transmitted to the slave eNB. It may be prepared separately and the radio signal may be transmitted to the slave eNB.

  The slave eNB transmits the second radio signal to the master eNB after a predetermined time x has elapsed after receiving the first radio signal (S605). Note that the predetermined time x is known to the master eNB. The second radio signal is, for example, a physical random access channel (PRACH) that uses the sequence specified in S603. Further, the second radio signal may be a PRACH using a known sequence for the master eNB and the slave eNB, or a signal that indicates that the master eNB is the second radio signal. If it is, it may be another signal.

  When the master eNB receives the second radio signal, the master eNB acquires the reception time y. Then, the master eNB receives the reception time y, the transmission time x of the first radio signal, and the predetermined time x to wait until the second radio signal is transmitted after receiving the first radio signal in the slave eNB. From this, the propagation delay z is calculated (S606). Specifically, the master eNB calculates z = (y−t−x) / 2 to calculate the propagation delay z.

  Thereafter, the master eNB notifies the slave eNB of the information on the propagation delay z using the X2 interface (S607). Then, the slave eNB performs adjustment of the internal clock or adjustment of the transmission timing of the radio signal based on the notified propagation delay (S608).

  In this way, the slave eNB can ensure highly accurate time synchronization with the master eNB based on the radio signal from the master eNB. In addition, the process of above-mentioned S603-S608 may be repeated in multiple times. This makes it possible to recover even when an erroneous propagation delay is notified. The master eNB may repeat the processes of S603 to S606 a plurality of times, calculate the propagation delay z a plurality of times, calculate the average value thereof, and then notify the slave eNB of the average value. As a result, even if there is a temporary change in the propagation environment, it is possible to reduce the influence and establish accurate time synchronization.

Claims (16)

A base station device,
Receiving means for receiving a first radio signal transmitted from another base station apparatus;
Transmitting means for transmitting a second radio signal after a first predetermined time has elapsed since receiving the first radio signal;
The base station apparatus calculated based on the timing at which the other base station apparatus transmits the first radio signal, the timing at which the second radio signal is received, and the first predetermined time, and the other base station apparatus An acquisition means for acquiring propagation delay information of a wireless section with the base station device from the other base station device;
Control means for controlling the base station apparatus so as to be time-synchronized with the other base station apparatus based on the propagation delay information;
A base station apparatus comprising: The acquisition means acquires information on the first radio signal from the other base station apparatus before receiving the first radio signal,
The transmission means receives the first radio signal based on information notified from the other base station apparatus, and after the first predetermined time has elapsed after the reception means has received the first radio signal, Send signal,
The base station apparatus according to claim 1. The acquisition means acquires information on timing at which the first radio signal is transmitted from the other base station device before receiving the first radio signal;
When the receiving unit receives the first radio signal from the other base station apparatus before the second predetermined time has elapsed from the notified timing, the transmitting unit receives the first radio signal. Transmitting the second wireless signal after the first predetermined time has elapsed since reception;
The base station apparatus according to claim 1 or 2, characterized in that The acquisition means acquires information on the second radio signal to be transmitted by the transmission means from the other base station apparatus,
The transmission means transmits the second radio signal based on the notified information.
The base station apparatus according to claim 1, wherein the base station apparatus is a base station apparatus. The control means is based on the reception time in the base station device and the transmission time when receiving a radio signal including information on the propagation delay and the transmission time from the other base station device, By controlling the clock inside the base station device so that the clock inside the base station device matches the clock inside the other base station device, the base station device is controlled by the other base station. Control to synchronize with the device,
The base station apparatus according to claim 1, wherein the base station apparatus is a base station apparatus. The control means controls the timing of transmitting a signal based on the timing of receiving a radio signal from the other base station device and the propagation delay, thereby controlling the base station device to the other base station device. Control to synchronize with time,
The base station apparatus according to claim 1, wherein the base station apparatus is a base station apparatus. A base station device,
Transmitting means for transmitting the first radio signal;
Receiving means for receiving a second radio signal transmitted from another base station apparatus after a predetermined time has elapsed since the other base station apparatus received the first radio signal;
Based on the timing at which the first radio signal is transmitted, the timing at which the second radio signal is received, and the predetermined time, a radio section between the base station device and the other base station device Calculating means for calculating the propagation delay of
Notifying means for notifying the propagation delay information to the other base station apparatus;
Have
The other base station apparatus is controlled to be time-synchronized with the base station apparatus based on the propagation delay information.
A base station apparatus. The notifying means notifies the other base station apparatus of information related to the first radio signal before transmission of the first radio signal;
The base station apparatus according to claim 7. The notification means notifies the other base station apparatus of information related to the transmission timing of the first radio signal before the transmission of the first radio signal.
The base station apparatus according to claim 7 or 8, wherein The notifying means notifies the other base station apparatus of information on the second radio signal to be transmitted by the other base station apparatus;
The base station apparatus according to any one of claims 7 to 9, wherein The calculation means has a timing when the first radio signal is transmitted as t, a timing when the second radio signal is received as y, the predetermined time as x, and the propagation delay as z.
z = (y−t−x) / 2
To calculate the propagation delay z,
The base station apparatus according to any one of claims 7 to 10, wherein: The calculating means calculates the propagation delay a plurality of times and calculates an average value thereof,
The notifying means notifies the other base station apparatus of the average value;
The base station apparatus according to claim 7, wherein the base station apparatus is a base station apparatus. A control method for a base station apparatus,
A receiving step for receiving a first radio signal transmitted from another base station device; and
A transmission step of transmitting a second radio signal after a first predetermined time has elapsed since the transmission means received the first radio signal;
The base station apparatus calculated by the acquisition means based on the timing at which the other base station apparatus transmits the first radio signal, the timing at which the second radio signal is received, and the first predetermined time An acquisition step of acquiring, from the other base station device, information on the propagation delay of the radio section between the other base station device, and
A control step for controlling the base station apparatus to be time-synchronized with the other base station apparatus based on the propagation delay information;
A control method characterized by comprising: A control method for a base station apparatus,
A transmitting step in which the transmitting means transmits the first radio signal;
A receiving step of receiving a second radio signal transmitted from another base station apparatus after a predetermined time has elapsed since the other base station apparatus received the first radio signal;
Based on the timing at which the calculating means transmits the first radio signal, the timing at which the second radio signal is received, and the predetermined time, the base station apparatus and the other base station apparatus A calculation step of calculating the propagation delay of the wireless section between,
A notifying step for notifying the other base station apparatus of the propagation delay information;
Have
The other base station apparatus is controlled to be time-synchronized with the base station apparatus based on the propagation delay information.
A control method characterized by that. In a computer provided in a base station apparatus having a receiving means for receiving a radio signal and a transmitting means for transmitting a radio signal,
Controlling the receiving means to receive a first radio signal transmitted from another base station device;
Controlling the transmitting means to transmit a second radio signal after a first predetermined time has elapsed since receiving the first radio signal;
The base station apparatus calculated based on the timing at which the other base station apparatus transmits the first radio signal, the timing at which the second radio signal is received, and the first predetermined time, and the other base station apparatus A step of acquiring information on propagation delay of a wireless section with the base station device from the other base station device;
Controlling the base station apparatus to be time-synchronized with the other base station apparatus based on the propagation delay information;
A program for running In a computer provided in a base station apparatus having a receiving means for receiving a radio signal and a transmitting means for transmitting a radio signal,
Controlling the transmitting means to transmit a first radio signal;
Controlling the receiving means from another base station apparatus so as to receive a second radio signal transmitted after a predetermined time has elapsed since the other base station apparatus received the first radio signal. When,
Based on the timing at which the first radio signal is transmitted, the timing at which the second radio signal is received, and the predetermined time, a radio section between the base station device and the other base station device Calculating a propagation delay of
Notifying the other base station apparatus of the propagation delay information;
And execute
The other base station apparatus is controlled to be time-synchronized with the base station apparatus based on the propagation delay information.
A program characterized by that.

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