JP4661430B2 - Mobile communication system, base station controller, phase shift correction method used therefor, and program thereof - Google Patents

Description

  The present invention relates to a mobile communication system, a base station control device, a phase shift correction method used therefor, and a program thereof, and more particularly to correction of a phase shift between a radio base station and a base station control device.

  A mobile communication system represented by a mobile phone has become an information transmission means indispensable in today's information society. In a mobile communication system, user data such as voice / packet transmitted from a mobile terminal arrives at a base station controller via a radio base station. At that time, since the area where one radio base station can receive data is limited, it is possible to perform mobile communication from any location by installing a plurality of radio base stations.

  Therefore, in the above mobile communication system, when a mobile terminal moves to an area covered by another radio base station beyond the area covered by a specific radio base station during communication, the mobile terminal It will be necessary to communicate using a station. At that time, in order to avoid the temporary interruption of communication at the moment when the radio base station is switched, if the mobile terminal exists near the boundary of the coverage area of a plurality of radio base stations, A technique that enables a terminal to communicate simultaneously with a plurality of radio base stations is used (see FIG. 7).

  That is, in FIG. 7, when the mobile terminal 7 exists near the boundary between the cover area 101 of the radio base station (A) 6-1 and the cover area 102 of the radio base station (B) 6-2, the mobile terminal 7 can communicate simultaneously with the radio base station (A) 6-1 and the radio base station (B) 6-2. In this case, user data from the mobile terminal 7 is sent to the base station controller 5 through the radio base station (A) 6-1 and the radio base station (B) 6-2, and the base station controller 5 sends a core network. (Core Network) 4 is transmitted.

  The time at which the user data transmitted from the plurality of radio base stations (A) 6-1 and (B) 6-2 to the base station control device 5 reaches the base station control device 5 is the radio base station (A) 6- 1, (B) 6-2 and the base station controller 5 depend on the transmission delay time, so the base station controller 5 starts from each radio base station (A) 6-1 and (B) 6-2. User data is received at different timings.

The base station controller 5 receives user data from the radio base stations (A) 6-1 and (B) 6-2 and the base station controller 5 with the radio base stations (A) 6-1 and (B) 6-2. The user data is transmitted to the core network 4 after the maximum transmission delay time elapses. At this time, the transmission timing after the lapse of the maximum transmission delay time is
Base station controller transmission time (C)
= Radio base station transmission time (A)
+ Phase difference between radio base station and base station controller (α)
+ Maximum transmission delay (β) (1)
(See FIG. 8).

  Here, the “radio base station transmission time” is the time when the radio base stations (A) 6-1 and (B) 6-2 transmit user data to the base station control device 5, and together with the user data, the base station It is transmitted to the control device 5. The “phase difference between the radio base station and the base station controller” (hereinafter referred to as phase difference) is the time recognized by the radio base stations (A) 6-1 and (B) 6-2 and the base station controller 5. Is the difference from the recognized time, measured by the synchronization process when the system is started, and thereafter held by the base station control device 5.

  As shown in the above equation (1), when the base station controller 5 transmits user data to the core network 4, the radio base stations (A) 6-1 and (B) 6 are used by using the phase difference. -2 is performed to convert the time recognized by -2 into the time recognized by the base station controller 5.

In this case, in FIG. 8, the base station controller 5 adds the phase difference (α) to the radio base station transmission time (A) given to the received user data, so that the user data is transmitted to the radio base station (A). 6-1 (B) The time (B) transmitted from 6-2 is
Time when user data was transmitted from the radio base station (B)
= Radio base station transmission time (A) + phase difference (α)
... (2)
Calculate with the following formula.

Next, the base station controller 5 adds the maximum transmission delay amount (β) to the time (B) when the user data is transmitted from the radio base station, thereby obtaining the base station controller transmission time (C),
Base station controller transmission time (C)
= Time when user data is transmitted from the radio base station (B)
+ Maximum transmission delay (β) (3)
Calculate with the following formula. The above equation (1) is derived from these equations (2) and (3).

  In the mobile communication system described above, a GPS receiver that generates a reference time based on a signal from a GPS (Global Positioning System) satellite is provided in the base station control device, and the base station control device is based on the reference time. A method has been proposed in which the time of each radio base station is synchronized with the time of the base station controller by creating time reference information and sending it to each radio base station (see, for example, Patent Document 1).

  In the mobile communication system, the downlink data from the base station controller is transmitted to the radio base station having the longest transmission delay time with the buffer time “0”, and is transmitted to other radio base stations. On the other hand, a method of transmitting by applying a buffer time corresponding to the degree of relative shortness of the transmission delay time has been proposed (see, for example, Patent Document 2).

JP 2000-023245 A JP 2003-333647 A

  Therefore, in the above-described conventional mobile communication system, the base station controller holds the synchronization processing failure at the time of system setting or a clock shift between the radio base station and the base station controller after the system setting. When a difference occurs between the phase difference and the actual phase difference, there arises a problem that the base station control device cannot correctly determine the user data transmission timing to the core network.

  Further, in the conventional mobile communication system, when the phase difference held by the base station control device is smaller than the actual phase difference, the transmission timing is advanced, so that transmission is performed before frame reception as shown in FIG. The problem of reaching timing occurs.

  In FIG. 9, the phase difference (α) is the actual phase difference between the radio base station and the base station controller, and the phase difference error (γ) is the phase difference recognized by the base station controller and the actual phase difference. Difference. That is, the base station controller recognizes the phase difference as “phase difference (α) + phase difference error (γ)”. Originally, the time (B) of the base station controller corresponding to the radio base station transmission time (A) is “radio base station transmission time (A) + phase difference (α)”. Since time calculation is performed based on “base station transmission time (A) + phase difference (α) + phase difference error (γ)”, a phase difference error (γ) shift occurs at time (B) of the base station controller. .

  Furthermore, in the conventional mobile communication system, when the phase difference held by the base station control device is larger than the actual phase difference, the transmission timing is delayed. Therefore, as shown in FIG. Data from the radio base station is awaited more than necessary, resulting in a transfer delay. These problems cannot be solved even by the techniques described in Patent Documents 1 and 2 above.

  Here, in FIG. 10, the phase difference (α) is the actual phase difference between the radio base station and the base station controller, and the phase difference error (γ) is the phase difference recognized by the base station controller and the actual level. It is the difference from the phase difference. That is, the base station controller recognizes the phase difference as “phase difference (α) + phase difference error (γ)”. Originally, the time (B) of the base station controller corresponding to the radio base station transmission time (A) is “radio base station transmission time (A) + phase difference (α)”. Since time calculation is performed based on “base station transmission time (A) + phase difference (α) + phase difference error (γ)”, a phase difference error (γ) shift occurs at time (B) of the base station controller. .

  Therefore, the object of the present invention is to solve the above-mentioned problems, to maintain the user data transmission time at an appropriate value, and to prevent data transmission due to occurrence of data transmission delay due to unnecessary buffering and shortening of standby time. It is to provide a mobile communication system, a base station control device, a phase shift correction method used therefor, and a program for the same, which can avoid communication and improve communication quality.

A mobile communication system according to the present invention is a mobile communication system that transmits user data from a mobile terminal received by a base station controller through a radio base station to a core network,
The base station control device includes a storage unit that holds a phase difference from the radio base station, a reception time of the user data when the user data is received, and a predefined reception timing of the user data. And a phase error detection means for determining whether the difference between the two exceeds a predetermined time, and a position held in the storage means when it is determined that the difference between the two exceeds a predetermined time. A correction unit that performs a phase difference correction process; and a unit that determines a transmission timing to the core network based on the phase difference corrected by the correction unit.

A base station control device according to the present invention is a base station control device that transmits user data from a mobile terminal received through a radio base station to a core network,
The storage means for holding the phase difference between the wireless base station and the reception time of the user data when the user data is received are compared with the reception expectation timing of the user data defined in advance. Phase error detection means for determining whether or not the difference exceeds a predetermined time, and correction for correcting the phase difference held in the storage means when it is determined that the difference between the two exceeds a predetermined time. And a means for determining a transmission timing to the core network based on the phase difference corrected by the correction means.

A phase shift correction method according to the present invention is a phase shift correction method used in a mobile communication system that transmits user data from a mobile terminal received by a base station controller through a radio base station to a core network,
The base station control device holds a phase difference with the radio base station in a storage means, and the user data reception time and the user defined in advance when the user data is received A second process for comparing the data reception expectation timing to determine whether or not the difference between the two exceeds a predetermined time; and when it is determined that the difference between the two exceeds a predetermined time, the storage means A third process for correcting the held phase difference and a fourth process for determining the transmission timing to the core network based on the phase difference corrected by the third process are executed.

  A program for a phase shift correction method according to the present invention is a program for a phase shift correction method used in a mobile communication system that transmits user data from a mobile terminal received by a base station control device through a radio base station to a core network. In the computer of the base station control device, a first process for storing a phase difference with the radio base station in a storage unit, and a reception time of the user data when the user data is received are defined in advance. A second process of comparing the user data reception expectation timing to determine whether the difference between the two exceeds a predetermined time, and when it is determined that the difference between the two exceeds a predetermined time A third process for correcting the phase difference held in the storage means and the phase difference corrected by the third process are transferred to the core network. And to execute a fourth processing for determining the transmission timing.

  That is, in the mobile communication system of the present invention, when the user data is received from the radio base station in the base station control device, the “user data reception time (A)” is used as a method for avoiding the above problems. “User data reception expected timing (B)” is compared, and if the difference between the two exceeds a certain time, it is determined that the retained phase difference is incorrect, and the base station controller autonomously detects the phase difference. After that, the transmission timing is determined based on the corrected phase difference, so that the user data buffer time of the base station controller can be kept at an appropriate time.

  In the mobile communication system of the present invention, the base station controller defines an expected reception timing for user data transmitted from the radio base station before phase difference correction, and the actual reception user data is received with the expected reception timing. The difference from the time is monitored, and the phase difference between the radio base station and the base station control device held by the base station control device is autonomously corrected when the difference is greater than or equal to a certain value.

  In the mobile communication system of the present invention, the base station controller uses the corrected phase difference when determining the transmission timing of the user data received from the radio base station to the network side after the phase difference correction. ing. Through the above processing, in the mobile communication system of the present invention, it is possible to keep the buffer time of user data in the base station control device at an appropriate time.

  Thereby, in the mobile communication system of the present invention, it is possible to keep the user data transmission time in the base station control device at an appropriate value even when an error occurs in the phase difference between the radio base station and the base station control device. It becomes. Therefore, in the mobile communication system of the present invention, it is possible to avoid the occurrence of data transmission delay due to unnecessary buffering and the loss of data due to shortened standby time, and the communication quality can be improved. .

  When the above phase difference correction method is not applied, the communication quality deteriorates as the phase error generated in the base station control apparatus increases, so that high clock accuracy is required for the base station control apparatus. . On the other hand, when the above-described phase difference correction method is applied, the phase error between the radio base station and the base station controller is corrected autonomously, so that high clock accuracy is not required for the base station controller. Become. Therefore, in the mobile communication system of the present invention, the cost can be reduced by reducing the clock accuracy.

  In the present invention, the user data transmission time can be maintained at an appropriate value by adopting the configuration and operation as described below, which results from the occurrence of data transmission delay due to unnecessary buffering and the reduction of standby time. Data omission can be avoided and communication quality can be improved.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a schematic operation of a mobile communication system according to an embodiment of the present invention. FIG. 1A shows the operation before the phase difference correction, and FIG. 1B shows the operation after the phase difference correction. Since the mobile communication system according to the embodiment of the present invention has the same configuration as the conventional mobile communication system shown in FIG. 7, the description thereof is omitted.

  In the mobile communication system according to the embodiment of the present invention, the base station controller defines an expected reception timing for user data transmitted from the radio base station before phase difference correction, and the expected reception timing and the actual user The difference between the time when the data is received is monitored, and the phase difference between the radio base station and the base station controller held by the base station controller is autonomously corrected when the difference is greater than a certain value. [See FIG. 1 (a)].

  Further, in the mobile communication system according to the embodiment of the present invention, the base station control device determines the transmission timing of the user data received from the radio base station after the phase difference correction when determining the transmission timing to the network side. The phase difference is used [see FIG. 1 (b)]. With the above processing, in the mobile communication system according to the embodiment of the present invention, the buffer time of user data in the base station control device can be maintained at an appropriate time.

  Thereby, in the mobile communication system according to the embodiment of the present invention, even when an error occurs in the phase difference between the radio base station and the base station controller, the user data transmission time in the base station controller is set to an appropriate value. Can keep. Therefore, in the mobile communication system according to the embodiment of the present invention, it is possible to avoid occurrence of data transmission delay due to unnecessary buffering and data omission due to shortened standby time, and improve communication quality. it can.

  When the above phase difference correction method is not applied, the communication quality deteriorates as the phase error generated in the base station control apparatus increases, so that high clock accuracy is required for the base station control apparatus. . On the other hand, when the above-described phase difference correction method is applied as in the embodiment of the present invention, the base station control is performed to autonomously correct the phase error between the radio base station and the base station controller. High clock accuracy is not required for the device. Therefore, in the mobile communication system according to the embodiment of the present invention, the cost can be reduced by reducing the clock accuracy.

  FIG. 2 is a diagram showing data reception / transmission timing when a phase error occurs in one embodiment of the present invention, FIG. 3 is a diagram showing a phase difference correction amount according to one embodiment of the present invention, and FIG. It is a figure which shows the data reception and transmission timing after the phase error correction by one Example of invention. The operation of the mobile communication system according to one embodiment of the present invention will be described with reference to FIGS. The mobile communication system according to one embodiment of the present invention has the same configuration as that of the conventional mobile communication system shown in FIG.

  In FIG. 2, there is a difference between the phase difference between the radio base station and the base station controller (hereinafter referred to as phase difference) held by the base station controller in one embodiment of the present invention and the actual phase difference. The relationship between user data reception timing and user data transmission timing is shown. Here, α is the actual phase difference between the base station and the base station controller, β is the maximum transmission delay amount for waiting for user data from the radio base station, and γ is the phase difference held by the base station controller. And the actual phase difference (hereinafter referred to as phase difference error), and the phase difference held by the base station controller is “phase difference α + phase difference error γ”.

  The base station control device converts the transmission time A to the time axis of the base station control device by adding the phase difference α to the transmission time A given to the user data transmitted from the radio base station. Originally, this conversion should be calculated as “transmission time A + phase difference α”. However, as shown in FIG. 2, when the base station controller misrecognizes the phase difference α, “B = Since transmission time A + phase difference α + phase difference error γ ”(B is a radio base station transmission time recognized by the base station controller) is erroneously calculated, phase difference error γ is used for recognizing the radio base station transmission time. A minute shift occurs. As a result, since the base station controller transmits user data to the network side at the time after the maximum transmission delay amount β has elapsed from the erroneous radio base station transmission time A, the user data is buffered more than necessary. It will be.

In the present embodiment, the user data reception expected time E is set by the base station controller, and when user data is received, the user data reception expected time E is compared with the actual user data reception time D, and the difference between them is compared. 3 exceeds a certain amount (phase error detection threshold), it is determined that the base station controller is erroneously recognizing, and phase difference correction as shown in FIG. 3 is performed. Here, the user data reception expected time E is the radio base station transmission time A given to the user data,
(Base station transmission time A + phase difference α held by the base station controller)
<User data reception expected time E
<(Base station transmission time A
+ Phase difference α held by the base station controller
+ Maximum transmission delay β) (4)
It is set like this.

For example, as a setting example of the user data reception expected time E,
Expected user data reception time E
= Base station transmission time A
+ Phase difference α held by the base station controller
+ Maximum transmission delay amount β / 2 (5)
There is an example of setting. The phase difference correction amount γ ′ is
Phase difference correction amount γ '
= User data reception expected time E
-User data reception time D (6)
It is calculated by the following formula.

  For subsequent received user data, it is possible to optimize the buffer time of the base station controller by determining the transmission time to the network based on the corrected phase difference as shown in FIG.

  FIG. 5 is a block diagram showing a configuration example of a base station control apparatus according to an embodiment of the present invention. In FIG. 5, a base station control apparatus according to an embodiment of the present invention includes a user data reception processing unit 1 and a storage device 2 that holds time information, maximum transmission delay amount β, phase difference α, and phase error detection threshold information. And a clock generation unit 3 that updates time information.

  The user data reception processing unit 1 uses the radio base station transmission time A given to the user data, the phase difference α held in the base station control apparatus, and the expected reception timing based on the maximum transmission delay amount β (/ 2). An expected reception timing calculation circuit 11 for calculating (user data expected reception time E), and a phase error is calculated from the expected reception timing and actual reception timing (user data reception time D) and compared with a phase error detection threshold. A phase error detection circuit 12, a phase correction circuit 13 for correcting the phase held in the storage device 2 when the phase error exceeds the phase error detection threshold, a radio base station transmission time A, a phase difference α (phase correction) The phase difference after phase correction), the transmission time calculation circuit 14 calculates the user data transmission time C to the network from the maximum transmission delay amount β.

  FIG. 6 is a flowchart showing the operation of the user data reception processing unit 1 of FIG. The operation of the user data reception processing unit 1 will be described with reference to FIGS.

When the base station controller receives user data from the radio base station, the expected reception timing calculation circuit 11 causes the phase difference between the radio base station and the base station controller (phase difference α + phase difference error γ), radio base station− Based on the maximum transmission delay β between base station controllers,
Expected reception timing E = base station transmission time A
+ Phase difference α
+ Phase difference error γ
+ Expected transmission delay (maximum transmission delay β / 2)
... (7)
The expected reception timing (expected user data reception time E) is calculated by the following equation (steps S1 and S2 in FIG. 6). In the above equation, the expected transmission delay amount is “maximum transmission delay amount β / 2”, but is an appropriate value within the range of “0” to “maximum transmission delay amount β”.

  Next, the phase error detection circuit 12 calculates a difference between the above reception expected timing (user data reception expected time E) and the actual user data reception time (user data reception time D), and the difference is the phase error. It is determined whether the detection threshold is exceeded. That is, the phase error detection circuit 12 acquires time information (user data reception time D) from the storage device 2 (step S3 in FIG. 6), acquires a phase error detection threshold from the storage device 2 (step S4 in FIG. 6), and It is determined whether the difference between the expected reception timing (expected user data reception time E) and the actual user data reception time (user data reception time D) exceeds the phase error detection threshold (| ED |> phase Error detection threshold) (step S5 in FIG. 6).

When the difference between the expected reception timing (user data reception expected time E) and the actual user data reception time (user data reception time D) exceeds the phase error detection threshold, the phase correction circuit 13
The phase difference is corrected based on the calculation result of the equation: phase difference after correction = phase difference before correction + timing difference. In this case, the phase correction circuit 13 calculates the phase difference correction amount γ ′ by the above equation (6) (step S6 in FIG. 6), and updates the phase difference stored in the storage device 2 with the calculation result (correction). Before: phase difference α + phase difference error γ, after correction: phase difference α + phase difference error γ + phase difference correction amount γ ′) (step S7 in FIG. 6).

  Here, the phase error detection threshold needs to be set to a value within a range that is larger than the maximum transmission delay amount β and smaller than the transfer delay time allowable in the base station controller. If the phase error detection threshold is too small, the phase difference correction process is frequently performed, the transmission timing from the base station controller to the network becomes unstable, and the processing capability of the base station controller may be compressed. Occurs. Conversely, if the phase error detection threshold is too large, there is a concern that the detection timing of the phase difference error will be delayed.

After correcting the phase difference described above, the transmission time calculation circuit 14 calculates the transmission time to the network side.
User data transmission time C
= Base station transmission time A + corrected phase difference + maximum transmission delay amount β
Phase difference after correction = phase difference α + phase difference error γ + phase difference correction amount γ ′
... (8)
And is transferred to a user data transmission processing unit (not shown) (step S8 in FIG. 6).

If the difference between the reception expected timing E and the time D when the user data is actually received does not exceed the phase error detection threshold, the transmission time calculation circuit 14 calculates the transmission time to the network side.
User data transmission time C
= Base station transmission time A + phase difference before correction + maximum transmission delay β
Phase difference before correction = phase difference α + phase difference error γ
... (9)
And is transferred to the user data transmission processing unit (step S9 in FIG. 6).

  Thus, in the present embodiment, by applying the above-described phase difference correction method, even when an error occurs in the phase difference between the radio base station and the base station control device, the user data transmission time in the base station control device Can be kept at an appropriate value. As a result, in this embodiment, it is possible to avoid the occurrence of data transmission delay due to unnecessary buffering and the loss of data due to shortened standby time, thereby improving the communication quality.

  When the above-described phase difference correction method is not applied, the communication quality deteriorates as the phase error generated in the base station controller increases, so that high clock accuracy is required for the base station controller. . In contrast, in this embodiment, by applying the above-described phase difference correction method, the phase error between the radio base station and the base station controller is corrected autonomously. Accuracy becomes unnecessary. Therefore, in this embodiment, the cost can be reduced by reducing the clock accuracy.

(A) is a figure which shows the operation | movement before phase difference correction | amendment of the mobile communication system by embodiment of this invention, (b) shows the operation | movement after phase difference correction | amendment of the mobile communication system by embodiment of this invention. FIG. It is a figure which shows the data reception and transmission timing at the time of phase error generation of one Example of this invention. It is a figure which shows the phase difference correction amount by one Example of this invention. It is a figure which shows the data reception / transmission timing after the phase error correction | amendment by one Example of this invention. It is a block diagram which shows the structural example of the base station control apparatus by one Example of this invention. It is a flowchart which shows operation | movement of the user data reception process part of FIG. It is a block diagram which shows the structure of the conventional mobile communication system. It is a figure which shows the transmission timing when there is no phase error in the conventional base station control apparatus. It is a figure which shows the transmission timing when the phase error of the negative direction in the conventional base station control apparatus generate | occur | produces. It is a figure which shows the transmission timing when the phase error of the positive direction generate | occur | produces in the conventional base station control apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 User data reception process part 2 Memory | storage device 3 Clock generation part 11 Expected reception timing calculation circuit 12 Phase error detection circuit 13 Phase correction circuit 14 Transmission time calculation circuit

Claims (19)

A mobile communication system for transmitting user data from a mobile terminal received by a base station controller through a radio base station to a core network,
The base station control device includes a storage unit that holds a phase difference from the radio base station, a reception time of the user data when the user data is received, and a predefined reception timing of the user data. And a phase error detection means for determining whether the difference between the two exceeds a predetermined time, and a position held in the storage means when it is determined that the difference between the two exceeds a predetermined time. A mobile communication system comprising: correction means for performing phase difference correction processing; and means for determining a transmission timing to the core network based on the phase difference corrected by the correction means.   The base station control device includes calculation means for calculating an expected reception timing of the user data based on a phase difference with the radio base station and a maximum transmission delay amount with the radio base station. The mobile communication system according to claim 1.   3. The calculation means according to claim 2, wherein the calculation unit calculates the reception expected timing of the user data by adding the transmission time of the radio base station, the phase difference, and a preset expected transmission delay amount. 4. Mobile communication system.   4. The mobile communication system according to claim 3, wherein the expected transmission delay amount is a value within a range of 0 to a maximum transmission delay amount with respect to the radio base station.   The correction means corrects the phase difference with a phase difference correction amount calculated based on an expected reception timing of the user data and a reception time of the user data. The mobile communication system according to any one of the above.   The fixed time is set to a value within a range larger than a maximum transmission delay amount with respect to the radio base station and smaller than a transfer delay time allowable in the base station controller. The mobile communication system according to any one of claims 1 to 5. A base station controller for transmitting user data from a mobile terminal received through a radio base station to a core network,
The storage means for holding the phase difference between the wireless base station and the reception time of the user data when the user data is received are compared with the reception expectation timing of the user data defined in advance. Phase error detection means for determining whether or not the difference exceeds a predetermined time, and correction for correcting the phase difference held in the storage means when it is determined that the difference between the two exceeds a predetermined time. Means for determining the transmission timing to the core network based on the phase difference corrected by the correcting means.   8. The calculation unit according to claim 7, further comprising a calculation unit that calculates an expected reception timing of the user data based on a phase difference with the radio base station and a maximum transmission delay amount with the radio base station. Base station controller.   9. The calculation means according to claim 8, wherein the calculation means adds the transmission time of the radio base station, the phase difference, and a preset expected transmission delay amount to calculate the expected reception timing of the user data. Base station controller.   The base station control apparatus according to claim 9, wherein the expected transmission delay amount is a value within a range of 0 to a maximum transmission delay amount with respect to the radio base station.   11. The correction means corrects the phase difference with a phase difference correction amount calculated based on an expected reception timing of the user data and a reception time of the user data. The base station control apparatus according to any one of the above.   8. The fixed time is set to a value within a range that is larger than a maximum transmission delay amount with respect to the radio base station and smaller than a transfer delay time allowable in the own device. Item 12. The base station control device according to any one of Items 11. A phase shift correction method used in a mobile communication system for transmitting user data from a mobile terminal received by a base station controller through a radio base station to a core network,
The base station control device holds a phase difference with the radio base station in a storage means, and the user data reception time and the user defined in advance when the user data is received A second process for comparing the data reception expectation timing to determine whether or not the difference between the two exceeds a predetermined time; and when it is determined that the difference between the two exceeds a predetermined time, the storage means Performing a third process for correcting the held phase difference and a fourth process for determining a transmission timing to the core network based on the phase difference corrected in the third process. A phase shift correction method.   The base station control device executes a fifth process of calculating an expected reception timing of the user data based on a phase difference with the radio base station and a maximum transmission delay amount with the radio base station. The phase shift correction method according to claim 13.   15. The fifth process according to claim 14, wherein the user data reception expectation timing is calculated by adding a transmission time of the radio base station, the phase difference, and a preset expected transmission delay amount. The phase shift correction method described.   16. The phase shift correction method according to claim 15, wherein the expected transmission delay amount is set to a value within a range of 0 to a maximum transmission delay amount with respect to the radio base station.   14. The third process according to claim 13, wherein the third process corrects the phase difference with a phase difference correction amount calculated based on an expected reception timing of the user data and a reception time of the user data. Item 17. The phase shift correction method according to any one of Items 16 above.   The fixed time is set to a value within a range larger than a maximum transmission delay amount with respect to the radio base station and smaller than a transfer delay time allowable in the base station controller. The phase shift correction method according to claim 13.   A program of a phase shift correction method used in a mobile communication system for transmitting user data from a mobile terminal received by a base station control device through a radio base station to a core network, the computer of the base station control device, A first process for storing a phase difference with the radio base station in a storage unit; a reception time of the user data when the user data is received; and a predetermined expected reception timing of the user data. A second process for determining whether or not the difference between the two exceeds a predetermined time, and the phase difference held in the storage means when it is determined that the difference between the two exceeds a predetermined time. A third process for performing a correction process and a fourth process for determining a transmission timing to the core network based on the phase difference corrected in the third process are executed. A program for causing.

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