JP2001053759A - Dynamic radio base station system and synchronizing method between dynamic radio base stations - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a dynamic radio base station system and a synchronizing method between dynamic radio base stations capable of counting sound/control signal transmission delay time to be generated on a signal transmission line and compensating transmission delay to automatically perform delay compensation for improvement of maintenability of a mobile telephone communication system. SOLUTION: In this dynamic radio base station system connected by ATM transmission having at least radio base stations 9 to 12 and a mobile telephone exchange station 13, the mobile telephone exchange station 13 is provided with a counting part to count ATM cell transmission delay time with each radio base station of the radio base stations 9 to 12 and a deciding part to decide a transmitted frame number based on a counting result obtained by the counting part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a dynamic radio base station system and a method for synchronizing dynamic radio base stations. More specifically, the present invention measures a transmission delay time of a voice / control signal generated on a signal transmission path and automatically corrects the transmission delay to improve the maintainability of a mobile telephone communication system. The present invention relates to a dynamic radio base station system and a method of synchronizing between dynamic radio base stations.

[0002]

2. Description of the Related Art FIG. 2 shows a conventional dynamic radio base station synchronization system. Conventional mobile telephone communication system 100
0 is composed of a switching network 900 and a plurality of wireless base stations 9 to 12 that establish communication with mobile terminals.

[0003] Within the switching network 900, there is a mobile telephone exchange 13 which performs communication connection between a mobile subscriber and a public telephone network subscriber or between mobile subscribers, and further performs channel connection switching control. Also, the signal transmission paths 300 to 302 and 40 are provided to the radio base stations 9 to 12.
0 is provided with an ATM switching device 15 which is connected by the ATM transmission method via the "0". The radio base stations 9 to 12 are:
Air format / ATM cell converter 1
6 and 17 are provided.

In a mobile telephone communication system 1000, a switching network 900 and radio base stations 9 to 12 are provided.
And ITU-T Recommendations (I.150, I.3
The ATM transmission method specified in 61) is adopted.
FIG. 2 shows a call signal transmission sequence between the mobile telephone exchange 13 and the radio base station 9 or the mobile telephone exchanges 13 and 10.

First, a case where a call 1r is generated from the mobile telephone terminal 1 to the mobile telephone terminal 2 in the conventional base station system will be described. The call 1r is received by the nearest wireless base station 9, and is converted into an ATM cell signal by the air format / ATM cell converter 16 in the wireless base station 9. The call 1r converted into an ATM cell signal is an ATM call.
The data is transmitted to the mobile telephone exchange 13 via the cell transmission line 300. In the mobile telephone exchange 13 which has received the call 1r, the central control unit 18 determines the mobile telephone terminal 1 from the destination number.
When it is confirmed that the other party of the call is the mobile telephone terminal 2, A
ATM switching device 15 to ATM cell transmission line 30
The call 1r converted into an ATM cell signal is transmitted to the radio base stations 9 and 10 covering the area where the mobile telephone terminal 2 is located via 0 and 301. The radio base stations 9 and 10 receiving the call 1r converted into the ATM cell signal are transmitted to the call 1r by the air format / ATM cell converters 16 and 17.
Is converted to an air format signal, and a reference clock (for example, a GPS (Global Positioning System) is used in the system so that a phase shift does not occur between both wireless base stations.
m: Global positioning system) Time or call 5r converted into an air format signal at the same timing (see FIG. 2) at the same timing (refer to FIG. 2) by synchronizing using time or highly accurate master clock from mobile telephone exchange 13. , 6r to the mobile telephone terminal 2.

In such a conventional invention, in order to improve the maintainability of the entire mobile telephone communication system, a voice / control signal transmission delay time generated on a signal transmission path as described below is measured and the delay correction is performed. Was given.

[0007]

As described above, in the transmission delay correction sequence in the mobile telephone communication system shown in FIG. 2, each ATM shown in FIG.
The transmission distances of the cell transmission lines 300 to 302 and 400 are artificially measured, and the respective ATM cell transmission lines 300 to 302 and
A value obtained by dividing the transmission distance of 00 by the signal transmission speed is defined as a transmission delay time, and based on the maximum transmission delay time among the transmission delay times derived in each of the ATM cell transmission lines 300 to 302 and 400, A procedure for determining a timing value at which an ATM cell signal is transmitted from the ATM cell generation device 6 before the time when the stations 9 to 12 wirelessly transmit to each mobile telephone terminal is shown.

[0008] The transmission delay correction value between the mobile telephone exchange 13 and the radio base stations 9 and 10 for the call 1r generated from the mobile telephone terminal 1 to the mobile telephone terminal 2 is based on the traffic fluctuation and the logical path route. The transmission delay correction value calculated as described above is used regardless of a change or the like. Therefore, call 1
After the occurrence of r, the traffic rapidly increases, and the transmission delay time increases due to the transmission fluctuation generated in the ATM switching device 15. When the increased transmission delay time in the ATM switching device 15 exceeds the maximum transmission delay time before the traffic suddenly increases, the call 1r is transmitted from the ATM cell generation device 6 to the radio base stations 9 and 10. However, by the actual air transmission time (see FIG. 2), the radio base stations 9 and 10 cannot receive the signals, and therefore the radio base stations 9 and
There is a problem that the timing of transmission from the mobile phone terminal 10 to the mobile telephone terminal 2 is missed.

When the radio base station 11 is newly added, first, the ATM from the ATM cell generation device 6 in the mobile telephone exchange 13 to the newly added radio base station 11 is changed.
The cell transmission distance 302 is measured. Then, the measured transmission distance is divided by the signal transmission speed to obtain a transmission delay time 1 between the ATM cell generator 6 in the mobile telephone exchange 13 and the newly added radio base station 11. Next, the obtained transmission delay time 1 is compared with the maximum transmission delay time used so far, and whether the transmission delay time 1 is smaller than the maximum transmission delay time,
Alternatively, even if the transmission delay time 1 is longer than the maximum transmission delay time, if the maximum transmission delay time up to that time is within any of the above ranges, or if the newly measured mobile telephone exchange 13 If the transmission delay time between the ATM cell generating device 6 and the newly added wireless base station 11 is the same as any one of the above-mentioned ranges of the maximum transmission delay time, the transmission delay correction value The system can be operated as it is without changing.

However, the transmission delay time 1
However, if the maximum transmission delay time is greater than the maximum transmission delay time and the maximum transmission delay time exceeds any of the above ranges, it is necessary to set a transmission delay correction value again. In addition, when setting a transmission delay correction value again, a field test using an actual device is performed, and a troublesome man-hour for checking whether transmission timing synchronization between the respective radio base stations is normally obtained is newly calculated based on the transmission delay correction value. Will occur.

Further, there is a daisy-chain system (a system in which ATM nodes are connected / added in multiple stages) in which a radio base station 12 is connected to the end of the radio base station 10 in FIG. In this system, it is also possible to adopt a complicated ATM cell transmission route from the ATM cell generating device 6 to the wireless transmitting station 12 via two ATM nodes, the ATM switching device 15 and the wireless base station 10. In such a system, the ATM cell transmission path 30
A method of calculating the transmission delay time 2 of 1,400 and adding the calculated transmission delay time 2 to the estimated transmission delay time as follows is adopted. The estimated transmission delay time is determined by two times of the TM switching device 15 and the wireless base station 10.
It is obtained by calculating the estimated transmission delay time in one ATM node.

[0012] However, in a complicated ATM cell transmission route through two ATM nodes,
Accurate calculation of the value of the transmission delay time cannot be expected, and after all, it is necessary to set a transmission delay correction value having a sufficient margin to maintain synchronous transmission between the radio base stations. Therefore, there has been a problem that the communication quality of the entire system is reduced.

The main object of the present invention is that even if the traffic fluctuates and the transmission delay time fluctuates due to the transmission fluctuation generated in the ATM switching device 15 in FIG. Even if a wireless base station (ATM node) is newly added to the network or a daisy-chain system is added to the ATM node so that a new ATM node is newly added and connected, the mobile telephone exchange 13 Accordingly, an object of the present invention is to provide synchronous transmission between wireless base stations that can constantly stabilize by constantly monitoring the ATM cell transmission delay time on each ATM cell transmission line and deriving an accurate transmission delay correction value.

[0014]

According to a first aspect of the present invention, there is provided a dynamic radio base station system having at least a radio base station and a mobile telephone exchange station connected by ATM transmission. The mobile telephone exchange, comprising: a measuring unit for measuring an ATM cell transmission delay time between each of the radio base stations and each of the radio base stations; and A dynamic radio base station system having a determining unit for determining a frame number is obtained.

According to the second aspect of the present invention, the dynamic wireless base station system further includes:
A dynamic radio base station system is provided, wherein the mobile telephone exchange has a notifying unit for notifying the radio base station of a transmission frame number from the determining unit.

According to a third aspect of the present invention, there is provided a dynamic radio base station system connected by ATM transmission having at least a radio base station and a mobile telephone exchange. The mobile telephone exchange includes a transmitting unit that transmits the OAM cell to the radio base station, a measuring unit that measures a cell transmission time from a time of receiving the received OAM response receiving cell from the radio base station and a time of transmitting the OAM cell. And a dynamic wireless base station system characterized by having the following.

According to a fourth aspect of the present invention, in the third aspect of the present invention, the mobile telephone switching center further comprises a voice communication unit based on the cell transmission time from the measuring unit. 4. The dynamic radio base station system according to claim 3, further comprising a number generation unit that generates a transmission frame number when transmitting a signal and / or a control signal.

According to a fifth aspect of the present invention, the mobile switching center is the mobile switching center according to any one of the first and second aspects and the second aspect. And a dynamic wireless base station system characterized by further comprising:

According to the sixth aspect of the present invention, the first step of measuring the ATM cell transmission delay time with each radio base station, and the measurement result of the cell transmission delay time in the first step. A dynamic inter-base-station synchronization method including a second step of determining a transmission frame number and a step of notifying the radio base station of the transmission frame number obtained in the second step is obtained.

According to the invention described in claim 7, the mobile telephone exchange transmits the OAM cell of the ATM maintenance operation management cell to the radio base station, and the OA from the radio base station.
Receiving an M response cell, and measuring the cell transmission time required from OAM cell transmission to OAM response cell reception when the OAM response cell is received, based on the measured cell transmission time. A method of synchronizing between dynamic radio base stations, wherein a transmission frame number is generated when transmitting a voice signal and / or a control signal.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION The dynamic radio base station system according to the present invention automatically increases the transmission delay time due to transmission fluctuations in an ATM switching device and the appearance of a new ATM node. AT, which is one of the ATM functions,
An M maintenance operation management cell (hereinafter, referred to as an OAM cell) is used.

In the mobile telephone exchange, a time stamp 1 synchronized with the system reference clock is added to the OAM cell, and the OAM cell is transmitted to each radio base station. When each radio base station receives an OAM cell to which a time stamp 1 is added, a time stamp 2 at the time of receiving the OAM cell is received.
Is compared with the time stamp 1 added at the time of transmission, and the difference between the time stamps 1 and 2 at the time of transmission and reception is added again as a time stamp 3 to the OAM response cell, and the OAM response cell is transmitted to the mobile switching center. I do.

The mobile telephone exchange has means for deriving a transmission delay correction value from the maximum ATM cell transmission delay time, using the time stamp 3 added at each radio base station as the ATM cell transmission delay time. In such a mobile telephone exchange, the ATM cell transmission delay time between the mobile telephone exchange and each radio base station is constantly measured by causing the OAM cell to be transmitted back to each radio base station at regular time intervals, AT
A means for monitoring a change in the ATM cell transmission delay time on the M cell transmission line is provided.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a mobile telephone communication system 1000 according to a first embodiment of the present invention. As shown in FIG.
Transmission routes 500 to when the OAM cells generated by the TM cell generation device 6 are transmitted to a plurality of radio base stations 9, 10,...
503 is shown.

FIG. 3 shows a mobile telephone exchange 13 shown in FIG. 1 and radio base stations 9 and 9 under its control using OAM cells.
Each ATM cell transmission delay time between 10 and 10 is measured, a transmission delay correction value is obtained based on the measurement result, and the delay correction value is added to the first byte of the ATM cell payload as a transmission frame number. (See 13 in FIGS. 5 to 7) shows a sequence until a communication signal is wirelessly transmitted from the wireless base station based on the air transmission time indicated by the transmission frame number.

FIG. 4 is a diagram showing an ATM layer OAM cell format used in the present invention specified in the ITU-T Recommendation (I.610). As shown in FIG. 4, this type of function of the OAM cell format is a so-called performance test function. That is, OAM Type area
"0010" in the function type area (Function
"0000" is added to Type area) as a fixed value. Function specific fiel
As for d), since the OAM type is a performance test function as described above, the internal format is as shown in FIG. The time stamp when the OAM cell is transmitted is represented by a time stamp field (TS: Time stamp f).
ield).

FIG. 8 shows that the time stamp added to the time stamp field in the OAM cell used in the present invention is a value obtained by the counter circuit 14 synchronized with the system reference clock. I have.
In this figure, the AT is transmitted to the ATM cell transmission line at a certain time interval.
It also shows that it is transmitted by the M cell generator.

Next, the operation of the embodiment of the present invention will be described.
This will be described in detail below with reference to FIG. 1 and FIGS. As shown in FIGS. 1 and 5 to 7, in all the calls, the ATM cell generator 6 in the mobile telephone exchange 13 shown in FIG.
The cell is transmitted at the cell transmission timing interval.
Also, the calls converted into the air format signal are transmitted at intervals of Δt to.

As shown in FIG. 1, a call 1r converted from an ATM cell signal transmitted from the ATM cell generator 6 at intervals of .DELTA.t.
Considering the ATM cell transmission delay time generated in the ATM cell transmission lines 300 and 301 and the ATM switching device 15, etc., the transmission time from the radio base stations 9 and 10 to the mobile telephone terminal 2 is calculated. , NΔt (n is an integer, in particular 1, 2 or 3: the same applies hereinafter) before being sent from the ATM cell generator 6. From the time wirelessly transmitted from the radio base stations 9 to 12 to each mobile telephone terminal, nΔ
The ATM cell transmission timing transmitted from the ATM cell generation device 6 before the time t is determined by the respective ATM cell transmission lines 300 to 302.
Or from the transmission distance of 400 and the signal transmission speed, each ATM
The transmission delay time of the cell transmission lines 300 to 302 and 400 is obtained. If the maximum delay time among the plurality of transmission delay times is within Δt, the ATM cell generator 6 determines
The transmission timing of the ATM cell signal transmitted at intervals of t is set to be Δt before the time of wireless transmission from the radio base stations 9 to 12 to each mobile telephone terminal. If the maximum delay time is within Δt to 2Δt, the transmission timing of the ATM cell signal transmitted from the ATM cell generation device 6 at intervals of Δt is determined by radio transmission from the radio base stations 9 to 12 to each mobile telephone terminal. 2Δt before the time. Further, if the maximum delay time is not less than 2Δt and less than 3Δt, AT
The transmission timing of the ATM cell signal transmitted from the M cell generation device 6 at intervals of Δt is 3Δ according to the time of radio transmission from the radio base stations 9 to 12 to each mobile telephone terminal.
t before.

The timing at which an ATM cell signal is transmitted from the ATM cell generation device 6 before the time when radio transmission is performed from the radio base stations 9 to 12 to each mobile telephone terminal is determined by the central control device 18 in FIG. Is generated on the basis of the transmission delay correction value notified to the ATM cell generation device 6 from the. ATM
The transmission delay correction value calculated from the cell transmission distance and the transmission speed is registered in the central control unit 18 (see FIG. 2).
When the TM cell generator 6 enters the service enabled state,
The central controller 18 notifies the ATM cell generator 6 (see PR in FIG. 2).

An ATM node (the radio base station 1 in FIG. 1)
1 and 12) are newly added, the ATM cell transmission delay time between the ATM cell generation device 6 and each of the radio base stations 11 and 12 is calculated from the transmission distance and the signal transmission speed. Register the correction value.

As shown in FIG. 1, when the mobile telephone communication system 1000 starts operation, first, the central control unit 18 in the mobile telephone exchange 13 sends the ATM cell generator 6.
, An OAM cell transmission request signal PR2 is transmitted. OA
The ATM cell generation device 6 in the mobile telephone exchange 13 which has received the M cell transmission request signal sends the radio base stations 9 and 10 under the mobile telephone exchange 13 as shown in FIG.
An OAM cell conforming to the OAM cell format is transmitted. At this time, the counter value obtained from the counter circuit 14 (equipped in the ATM cell generator 6 and all the radio base stations 9, 10,..., 12) synchronized with the system reference clock is added as a time stamp 1 to the time stamp field. Then, the OAM cell is transmitted to the radio base stations 9, 10,.
C3, C4, etc.) (the wireless base station 9 in FIG. 1 corresponds to 9 in FIG. 3, and the wireless base station 10 in FIG. 1 corresponds to 10 in FIG. 3).
Others are similarly represented. ). When the radio base stations 9 and 10 shown in FIG. 1 receive the OAM cell to which the time stamp 1 is transmitted from the ATM cell generator 6, the added time stamp 1 and the system reference provided in each radio base station are received. OA obtained from the counter circuit 14 synchronized with the clock
The counter value (time stamp 2) at the time of receiving the M cell is compared, and the difference obtained from these comparisons is compared with the time stamp 3
To the time stamp field of the return OAM response cell. OAM response cell (C5, C5 in FIG. 3)
6) is received by the ATM cell generator 6 in the mobile telephone exchange 13 shown in FIG. 1, and the time stamp 3 added to the time stamp field in each received OAM response cell is added to the ATM cell generator 6. And each radio base station 9, 1
The transmission delay time between 0 is reported to the central control unit 18 in the mobile telephone exchange 13 (PR3 in FIG. 3). The central controller 18 receiving this report adopts the maximum transmission delay time among the two transmission delay times, and if the value is smaller than Δt shown in FIGS. Is greater than or equal to Δt and less than 2Δt, “2” is represented by 2Δt or greater and 3Δ
If it is less than t, "3" is used as the transmission delay correction value, and AT
It notifies the M cell generation device 6 (PR4 in FIG. 3).

A call 1r destined for the mobile telephone terminal 2 generated from the mobile telephone terminal 1 shown in FIG. 1 is received by the radio base station 9 and is sent to the air format / ATM cell conversion device 16.
Is converted into an ATM cell signal. This ATM cell signal is transmitted via the ATM transmission line 300, the ATM switching device 15 in the mobile telephone exchange 13, and the ATM cell signal.
The data is transmitted to the M cell generation device 6. ATM cell generator 6
When the mobile phone terminal 2 receives information from the central controller 18 that the mobile telephone terminal 2 is located in, for example, both the coverage areas of the radio base station 9 and the radio base station 10, two types of the same logical channel are used. Generate an ATM cell signal. At this time, if the transmission delay correction value notified from the central controller 18 is “1”, the first byte in the ATM cell payload shown in FIG. 13 as “N + 1” (N = 0, 1, 2, 3,...: Transmission timing number).

The above two types of ATM cell signals are shown in FIG.
As shown in (1), the ATM cell generator 6 transmits the data to the radio base station 9 or 10 via the ATM cell transmission path 300 or 301 at intervals Δt before the actual air transmission time Δt (C7 in FIG. 3). C8 and FIG. 5). The wireless base stations 9 and 10 confirm the actual air transmission time from the transmission frame number in the transmitted ATM cell signal, and the wireless base stations 9 and 10 both call 5r and 6r at the same timing.
To each.

When traffic increases during transmission during a call between the mobile telephone terminals 1 and 2 and transmission fluctuation occurs in the ATM switching device 15, the ATM cell is lost to the ATM user cell at a certain time interval. As a result, the time from when the OAM cell transmitted from the ATM cell generating device 6 is transmitted to when it is received by each of the radio base stations 9 and 10 increases (the time stamp 3 increases). The central control unit 18 receiving the report of the transmission delay time obtained by the OAM cell folding back by the central control unit 18 makes the maximum transmission delay time more than Δt and 2Δ
When it is determined that the value has increased within the range of less than t, "2" is immediately notified to the ATM cell generator 6 as a transmission delay correction value from the central controller 18, and the ATM cell generator 6 performs the operation shown in FIG. 1 in the ATM cell payload shown in
"N + 2" is added to the byte as the transmission frame number, and the ATM is transmitted at intervals of Δt before 2Δt before the actual air transmission time.
The cell signal is transmitted from the ATM cell generator 6 to each radio base station 9,
10 is transmitted. Then, it is confirmed that the transmission fluctuation in the ATM switching device 15 has been eliminated.
The central control unit 18 makes a determination based on the transmission delay time obtained by the OAM cell folding, and if the maximum transmission delay time after eliminating the transmission fluctuation in the ATM switching device 15 is smaller than Δt, the central control unit 18 18 notifies the ATM cell generator 6 of "1" as a transmission delay correction value. In the ATM cell generator 6 which has received "1" as the transmission delay correction value, the first byte in the above-mentioned ATM cell payload shown in FIG.
1 "is set as the transmission frame number.
The M cell signal is transmitted to each of the radio base stations 9 and 10 via the ATM cell transmission line 300 or 301 at intervals Δt before the actual air transmission time (11 in FIG. 4) Δt. Will be done.

A mobile telephone communication system 1 shown in FIG.
When the wireless base station 11 is newly added while the 000 is operating, the mobile telephone exchange 1
The PR2 of FIG. 3 is transmitted from the central control device 18 in FIG. 3 as a request signal to transmit an OAM cell to be transmitted to the radio base station 11 at a fixed time interval. The above request signal P
The ATM cell generator 6 having received R2 adds the radio base station 11 to the OAM cell transmission destination list, and transmits the OAM cell to the radio base station 11 via the ATM cell transmission line 302. .

The OAM is performed by each of the radio base stations 9 to 11.
ATM cell generating device 6 that has received a time-stamped process at the time of cell transmission and reception and has returned an OAM response cell
Then, the time stamp 3 added to the time stamp field in each OAM cell is reported to the central control unit 18 as the transmission delay time of each ATM transmission line. The central controller 18 receiving the report derives the maximum transmission delay time from the plurality of transmission delay times. The newly obtained maximum transmission delay time exceeds the range in which the maximum transmission delay time has been applied (for example, less than Δt) and is equal to or more than Δt and 2Δt
If it is less, the central controller 18 notifies the ATM cell generator 6 of "2" as the transmission delay correction value. As a result, the transmission timing of the ATM cells transmitted from the ATM cell generating device 6 to the respective radio base stations 9, 10, 11 and 12 via the ATM cell transmission lines 300, 301 and 302 is as shown in FIG. It is before 2Δt of the actual air transmission time.

Similarly, when the radio base station 12 is newly added under the control of the radio base station 10 while the mobile telephone communication system 1000 shown in FIG. The control device 18 transmits to the ATM cell generation device 6 a request signal for transmitting an OAM cell transmitted at a constant period to the radio base station 12 as a request signal. The ATM cell generator 6 having received the request signal,
The wireless base station 12 is newly added to the OAM cell transmission destination list, wirelessly transmitted via the ATM cell transmission line 301, via the air format / ATM cell conversion device 17 in the wireless base station 10, and further via the ATM cell transmission line 400. The OAM cell is transmitted to the base station 12. Each of the radio base stations 9 to 12 performs a time stamp process when transmitting and receiving the OAM cell. Then, the ATM cell generating device 6 which has received the returned OAM response cell, the time stamp 3 added to the time stamp field in each OAM response cell.
To the central control unit 18 as the transmission delay time of each ATM transmission line. At the central controller 18 receiving the report,
In this way, the maximum transmission delay time is derived from the plurality of transmission delay times. Assuming that the newly obtained maximum transmission delay time exceeds the range to which the maximum transmission delay time has been applied, for example, not less than 2Δt and less than 3Δt, the central control unit 18 determines that the ATM cell generation unit 6
, "3" is notified as a transmission delay correction value. Thereby, the ATM cell generating device 6 sends the ATM cell transmission line 3
The transmission timing of the ATM cell transmitted to each of the radio base stations 9, 10, 11, 12 via 00, 301, 302 and 400 is earlier than the actual air transmission time 3Δt, as shown in FIG. It is possible to always maintain stable synchronous transmission between wireless base stations. It should be noted that the present invention is not limited to the above embodiments, and it is clear that each embodiment can be appropriately modified within the scope of the technical idea of the present invention.

[0039]

As is apparent from the above description, according to the present invention, each ATM cell transmission is performed based on the basic configuration of measuring one transmission delay time of the maintenance operation management function by the OAM cell in the ATM. An automatic measurement of the ATM cell transmission delay time occurring on the road and a delay correction value derived based on the result of the automatic measurement are provided.
This prevents data transmission disconnection caused by a change in the transmission delay time on the ATM cell transmission line due to traffic fluctuation during a call, and prevents the radio base station (A
Prevent the occurrence of complicated man-hours due to the artificial setting of delay correction values due to the new addition of TM nodes) and complicated work man-hours such as field tests, etc., and always achieve stable synchronization between wireless base stations. It has an advantageous effect that it can be performed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a mobile communication system of the present invention.

FIG. 2 is a diagram showing a transmission delay correction value setting sequence in a conventional mobile communication system.

FIG. 3 is a diagram showing a transmission delay correction value setting sequence in the mobile communication system of the present invention.

Fig. 4 ATM layer O specified in ITU-T Recommendation (I.610)
AM cell format.

FIG. 5 is a diagram showing an ATM cell transmission timing sequence when a transmission delay correction value is “1”.

FIG. 6 is a diagram showing an ATM cell transmission timing sequence when the transmission delay correction value is “2”.

FIG. 7 is a diagram showing an ATM cell transmission timing sequence when the transmission delay correction value is “3”.

FIG. 8 is a diagram showing the positioning of a counter circuit synchronized with a reference clock in a system required for the present invention and the transmission timing of an OAM cell.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 mobile telephone terminal 2 mobile telephone terminal 3 mobile telephone terminal 4 mobile telephone terminal 6 ATM cell generator 9 wireless base station 10 wireless base station 11 wireless base station 12 wireless base station 13 mobile telephone exchange 14 system reference Clock Synchronous Counter Circuit 15 ATM Switching Device 16 Air Format / ATM Cell Converter 17 Air Format / ATM Cell Converter 18 Central Controller 900 Switching Network 1000 Mobile Telephone Communication System

Continuation of the front page F term (reference) 5K030 GA11 HA10 HB11 HC09 JA10 JL01 KA03 LA15 LE17 MB06 5K067 AA13 BB02 CC04 DD25 DD51 DD57 EE02 EE10 EE16 EE65 EE66 EE71 EE72 GG01 HH05 JJ04 JJ21

Claims (7)

[Claims] 1. A dynamic radio base station system connected by ATM transmission having at least a radio base station and a mobile telephone exchange, wherein the mobile telephone exchange is a radio base station of each of the radio base stations. A measurement unit for measuring an ATM cell transmission delay time, and a determination unit for determining the transmission frame number based on a measurement result obtained by the measurement unit. . 2. The dynamic radio base station according to claim 1, wherein the mobile telephone exchange has a notifying unit for notifying the radio base station of a transmission frame number from the determining unit. Bureau system. 3. A dynamic radio base station system connected by ATM transmission having at least a radio base station and a mobile telephone exchange, wherein the mobile telephone exchange transmits an OAM cell to the radio base station. A dynamic wireless base station system, comprising: a transmitting unit; and a measuring unit that measures a cell transmission time from a time of receiving an OAM response receiving cell from a received wireless base station and a time of transmitting the OAM cell. 4. The mobile telephone exchange according to claim 1, further comprising: a number generation unit configured to generate a transmission frame number for transmitting a voice signal and / or a control signal based on the cell transmission time from the measurement unit. 4. The method according to claim 3, wherein
3. The dynamic wireless base station system according to claim 1. 5. The mobile telephone exchange further comprises a mobile exchange according to any one of claims 1 to 2 and a mobile exchange according to any one of claims 2 to 4. Dynamic wireless base station system. 6. A first step of measuring an ATM cell transmission delay time with each radio base station, and a second step of determining a transmission frame number based on the measurement result of the cell transmission delay time in the first step. And a step of notifying the wireless base station of the transmission frame number obtained in the second step. 7. The mobile telephone switching center transmits an OAM cell of an ATM maintenance / operation management cell to a radio base station, receives an OAM response cell from the radio base station, and receives the OAM response cell. OAM cell transmission
Measuring a cell transmission time required until the AM response cell is received, and generating a transmission frame number when transmitting a voice signal and / or a control signal based on the measured cell transmission time. Dynamic radio base station synchronization method.