JPH0955979A - Delay time adjusting system for mobile communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the occupied time of a transmission line and a radio transmission line and the signal processing load of a central station, which are used for measuring a delay time for adjusting the transmission timing of a radio signal. SOLUTION: The central station 1 delays a delay measuring instruction signal S1m by a delay time Di and sends it to the line transmission line 4i and a specified radio base station 2i. At the time of receiving the delay measuring instruction signal S1m addressed to itself from the line transmission line 4i, the radio base station 2i sends back a signal S1r to the central station 1 through the line transmission line 4i in return. The central station 1 receives the returned signal S1r to measure a signal transmission time Ti from the sending of the delay measuring instruction signal S1m to the reception of the returned signal S1r. The central station 1 is capable of simultaneously measuring this signal transmission time Ti concerning all the radio base stations S2. In order to synchronize the transmission timings of the radio signals S2 transmitted by the radio base stations 2 to each other, the central station 1 sets or updates the delay time Di based on the measured signal transmission time Ti.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a plurality of radio base stations that communicate with mobile stations in the area using radio signals whose transmission timings are synchronized with each other, and a central station that controls these radio base stations through a line transmission line. The present invention relates to a delay time adjustment method for a mobile communication system.

[0002]

2. Description of the Related Art A conventional delay time (phase) adjusting method for this type of mobile communication system is disclosed in Japanese Patent Laid-Open No. 145469/1993. As shown in the block diagram of FIG. 7, this mobile communication system includes a central station 56 having a wireless transmission function as a reference station, and a plurality of peripheral stations (radio base stations) 57 connected to the central station 56 by transmission lines 62. And a phase difference (delay time difference) measuring station 58 installed at a position where the radio waves S63 from these peripheral stations 57 can be received.

The central station 56 has a function of generating a synchronization confirmation signal at regular time intervals and sending it to each peripheral station 57 through the transmission line 62, and a phase synchronization execution command from the phase difference measuring station 58 through the transmission line 65. A function of receiving and analyzing, generating a control command signal including a phase synchronization signal for instructing the start and stop of the transmitter of the peripheral station 57, and transmitting the control command signal to each peripheral station 57, for measuring the phase difference as a reference station of the peripheral station 57. Radio wave S carrying a reference signal
According to the function of transmitting 64 from the transmitting antenna 60 and the phase difference information received from the phase difference measuring station 58, the sending time (transmission timing) of all signals sent to each of the peripheral stations 57 via the transmission path 62 is adjusted. Have a function.

Each of the peripheral stations 57 has a function of receiving the signal from the central station 56 through the transmission line 62, transmitting it on the radio wave S63 and transmitting it by the transmitting antenna 59. In parallel with this, the control command signal is decoded and the radio wave is transmitted. It has a function of performing execution and stop control of S63 transmission.

The phase difference measuring station 58 receives the radio wave S63 including the synchronization confirmation signal transmitted from the peripheral station 57 at a constant time interval. If the reception is not successful, the central station 5
A phase synchronization execution command signal is sent to the signal No. 6. Central station 5
When receiving the phase synchronization execution command signal from the phase difference measuring station 58, 6 generates a peripheral station control command signal including the phase synchronization signal and sends it to the peripheral station 57, and itself receives a reference signal as a reference from the transmitting antenna 60. The transmitted radio wave S64 is transmitted. In the peripheral station 57, only the peripheral station 57 that performs the measurement receives the radio wave S63 including the phase synchronization signal according to the control command from the central station 56.
Is transmitted, and the other peripheral stations 57 stop transmitting the radio wave S63. The phase difference measuring station 58 receives the radio wave S364 including the reference signal and the radio wave S63 including the phase synchronization signal by the receiving antenna 61, measures the phase difference, and sends the information to the central office 56. Upon receiving the information, the central station 56 adjusts the signal transmission time to the peripheral station 56 whose phase difference is measured according to the information, and executes the phase synchronization operation for the next peripheral station 57. The central station 56 similarly performs sequential measurement and transmission time adjustment for all peripheral stations 57,
The synchronization of radio signals transmitted from all peripheral stations 57 is realized.

[0006]

However, in the above-mentioned conventional delay time adjusting method for the mobile communication system, the phase difference measuring station receives the radio waves from a plurality of radio base stations having the same frequency in parallel and individually. Is impossible, so
The central station has a drawback that only one signal phase difference (signal delay time) from one radio base station can be measured by transmitting the synchronization confirmation signal once. In order to solve this, it is possible to measure the delay time of each radio base station using radio waves of individual frequency, but this method impairs the advantage of the mobile communication system by the small radio zone of effective use of the frequency band. It will be.

Further, in the conventional delay time adjustment method, it is impossible to identify the radio base station in which the phase shift (transmission time difference) of the radio wave signal to be transmitted has occurred, and every radio base station fails every time a failure occurs. There was a problem that it was necessary to measure the phase (delay time) for the station.

Therefore, in the conventional delay time adjusting method,
A great deal of time and load was imposed on this mobile communication system in measuring the delay time between a plurality of radio base stations.

Therefore, an object of the present invention is to improve the above-mentioned disadvantages of the prior art and to connect a central station and a radio base station used for delay time measurement for adjusting transmission timing of radio signals, and The object is to reduce the occupied time of the wireless transmission path used by the wireless base station and the load on the central station, and also to shorten the time during which the wireless signal transmitted from the wireless base station is transmitted in a transmission timing shift state.

[0010]

One of the delay time adjusting methods of a mobile communication system according to the present invention is to communicate with a mobile station within a range by using radio signals which are respectively arranged in a plurality of radio zones and whose transmission timings are synchronized with each other. And a central station that connects each of the wireless base stations by a line transmission path, and each of the wireless base stations is sent from the central station via the line transmission path. In the delay time adjusting method for a mobile communication system for converting a predetermined signal into the radio signal and transmitting the radio signal, the central station transmits the predetermined signal designating a destination radio base station and the delay measurement command signal to the corresponding line transmission. Signal transmission means for delaying each of the radio base stations by a set delay time and transmitting the signals, and a loopback signal from each of the radio base stations. Return signal receiving means for receiving the return signal from each of the radio base stations, and a signal transmission time from supply of the delay measurement command signal to the line transmission path to reception of the return signal by the return signal receiving means. The signal whose measured delay time is set in the signal transmitting means so that the signal transmission time measuring means for each measurement and the transmission timing of the wireless signal transmitted from each of the wireless base stations are synchronized Delay time management means for updating based on the transmission time, each of the radio base station, when receiving the delay measurement command signal addressed to itself from the line transmission path, the delay measurement command signal to the return signal And a line switching means for sending back to the central office via the line transmission path.

In the delay time adjusting system of the mobile communication system, the central station controls central station control means for instructing generation of the delay measurement command signal and the predetermined signal, and the delay measurement command signal corresponding to the generation command. And signal generation means for generating the predetermined signal and supplying it to the signal transmission means, wherein the delay time management means sets the delay time set in the signal transmission means for each of the radio base stations. An individual storage means for storing each of them, the central station control means obtains the set delay time from the delay time management means for all the radio base stations, and stores the total storage means; A storage information detecting means for detecting the disappearance of the information of the delay time stored in all the storage means; Can be the structure further comprising a delay time measuring station determining means for the generation instruction of the delay measurement command signal containing the specified the radio base station-out delivery destination delay measurement command signal.

Another delay time adjusting method for a mobile communication system according to the present invention is a radio base station which is arranged in each of a plurality of radio zones and which communicates with a mobile station in the area using radio signals synchronized with each other. A central station connecting each of the radio base stations by a line transmission path, and each of the radio base stations transmits the predetermined signal transmitted from the central station via the line transmission path to the radio signal. In the delay time adjustment method of a mobile communication system for converting and transmitting to a central station, the central station instructs the generation of the predetermined signal and the delay measurement command signal designating a destination wireless base station, and the generation. When a signal generation unit that generates the delay measurement command signal and the predetermined signal corresponding to an instruction and the delay measurement command signal and the predetermined signal addressed to itself are received, these signals are generated. Radio transmission provided for each of the radio base stations that transmits the delayed measurement command signal via the line transmission line while transmitting the signal to the connected line transmission line after delaying by a predetermined delay time. A station connection unit, signal transmission time measuring means for measuring the signal transmission time from the supply of the delay measurement command signal to the line transmission path to the reception of the return signal for each of the radio base stations, and the radio transmission A delay time for updating the delay time set for each of the wireless transmission station connection units based on the measured signal transmission time so that the transmission time of the wireless signal from each base station is synchronized. With management means,
When each of the radio base stations receives the delay measurement command signal addressed to itself from the connected line transmission line, the delay measurement command signal is used as the folding signal to the central station via the line transmission line. A line switching circuit for sending back is provided.

In the delay time adjusting method of the mobile communication system, the delay time management means further comprises individual storage means for storing the set delay time for each of the radio base stations, and the central station. The control unit obtains all the set delay times from the delay time management unit and stores them, and an individual storage unit and an information loss of the delay time stored in all the storage units. Delay time information detecting means for detecting, and delay time measuring station determining means for deciding the radio base station for transmitting the delay measurement command signal according to a state of information loss of the delay time and notifying the signal generating means. Can be further provided.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a delay time adjustment system for a mobile communication system according to the present invention.

The mobile communication system shown in FIG. 1 is a small zone mobile communication system such as a cellular car telephone system, and has n service areas (n is a plurality).
Is divided into wireless zones. n wireless base stations 2
a, 2b, 2c, ..., 2 (i-1), 2i, 2 (i +
1), ..., 2 (n-1) and 2n are respectively arranged in the corresponding wireless zones. i represents an arbitrary number from 1 to n. Each of the radio base stations 2a to 2n has radio signals S2a and S2 whose transmission signal timings are synchronized with each other.
b, S2c, ..., S2 (i-1), S2i, S2 (i +
1), ..., S2 (n-1) and S2n are used to communicate with a mobile station (not shown) in the area. In addition, the radio base stations 2a to 2n are connected to the line transmission lines 4a, 4b, 4
c, ..., 4 (i-1), 4i, 4 (i + 1), ..., 4
(N-1) and 4n are connected to the central office 1, respectively. The central station 1 controls the radio base stations 2a to 2n. Hereinafter, the wireless base stations 2a to 2n and the line transmission path 4 will be described.
When any one of a to 4n and radio signals S2a to S2a is shown, the reference numeral is suffixed with i, and when the whole is shown, the reference numeral is not suffixed. Now, when the radio base station 2i communicates with the mobile station, the central station 1 transmits a predetermined signal to the radio base station 2i via the line transmission line 2i, and the radio base station 2i transmits the predetermined signal to the radio signal. To the mobile station. Note that each of the radio base stations 2 uses only the radio transmission station (TX) 30i in the delay time adjustment method in the present embodiment, so that the central station 1 receives signals from the mobile stations.
The illustration of a wireless receiving station that sends a signal corresponding to this signal is omitted.

Now, the delay time adjusting method according to this embodiment will be described.
1 m is transmitted to each of the line transmission paths 2i from the wireless transmission station connection unit, which is a connection circuit to each of the wireless base station 2i (wireless transmission station 30i), almost simultaneously, and the signal S1m has a delay time (signal transmission time). ) Is further sent to the radio base station 2i to be measured. The wireless base station 2i whose delay time is to be measured may be the entire wireless base station 2 or only one wireless base station 2. Also, the transmission timing of the delay measurement command signal S1m is delayed and transmitted by the delay time Di set for each of the wireless transmission station connection units, that is, for each of the wireless base stations 2. Upon receiving the delay measurement command signal S1m from the line transmission line 4i, the radio base station 2i loops back the delay measurement command signal S1m at the line switching unit and outputs it as the loopback signal S1r.
Sent back to the central office 1 via. The central office 1 receives the loopback signal S1r from the line transmission line 4i, and approximately the signal round-trip time Tli and the delay time D through the line transmission line 4i from the transmission of the delay measurement command signal S1m to the reception of the loopback signal S1r.
The signal transmission time Ti, which is the sum of two times i, is measured. Then, the central station 1 transmits the radio signal 4i from each of the radio base stations 2i based on the measured signal transmission time Ti.
The delay time Di set in each of the wireless transmission station connection units is updated so that the signal timings of the above are synchronized with each other.

The central station 1 stores the delay times D1 to Dn of all the radio base stations 2 in the memory of the built-in central station control unit, and the radio base stations 2i corresponding to each of the radio transmission station connection units are stored. The delay time Di is stored in each memory of the wireless transmission station connection unit. The central station control unit
When the disappearance of the delay times D1 to Dn stored in its own memory and the delay times D1 to Dn stored in the memory of the wireless transmission station connection unit is detected, the disappearance of the delay times D1 to Dn to be stored is detected. The delay measurement command signal S1m is transmitted from the wireless transmission station connection unit according to the state. The wireless base station 2i to which the delay measurement command signal S1m is sent at this time may be all stations or only one station. After this delay time measurement, the delay time Di is updated in the same manner as described above to adjust the delay time between the radio base stations 2i.

As described above, in the delay time adjustment method for the mobile communication system according to the present embodiment, the signal delay time difference between the radio base stations 2i is measured based on the instruction of the central station control unit in the central station 1 and the line transmission. The delay measurement command signal passing through the path 4i and its return signal can be used for all the radio base stations 2 at once. Thus, by simultaneously measuring the signal transmission time Ti for all the radio base stations 2, the occupied time of the line transmission path 4 for adjusting the delay time between the radio signals S2i and the load of the central station 1 are adjusted. Can be reduced.

The delay time Di obtained by measuring the signal transmission time Ti is stored and managed separately in the wireless transmission station connecting section and the central station control section. Therefore, the central station control section
The delay time Di stored separately is detected at a constant time interval to detect a failure related to the transmission timing synchronization of the wireless signal S2 and to identify the wireless base station 2i in which the failure has occurred, and a method according to the failure method is automatically detected. Can be determined and executed. Therefore, in the present embodiment, even if a transmission timing shift occurs between the radio signals S2i for some reason, it is possible to shorten the time until the restoration.

FIG. 2 shows a central station 1 used in the embodiment of FIG.
It is a block diagram of. FIG. 3 is a block diagram of the wireless transmission station connection unit 12i used in the central office 1.

The operation of the central station 1 when measuring and adjusting the delay time between the central station 1 and the radio base station 2 will be described below.

The central station control unit 10 of the central station 1 measures the first signal transmission time Ti (delay time difference measurement) as follows.
The delay measurement command S11a, which is a simultaneous measurement command designating delay time measurement of all the radio base stations 2, is output to the signal generation unit 11. The signal transmission time Ti is measured when the central station 1 does not need to send and receive a predetermined signal for communication between the wireless base station 2 and the mobile station. When the radio base station 2i communicates with the mobile station, the central station control unit 10 outputs a command for generating the above-mentioned predetermined signal to the signal generation unit 11, and the signal generation unit 11 generates the predetermined signal to generate the radio base station. Will be supplied to the station 2i. Upon receiving the delay measurement command S11a, the signal generator 11
The delay measurement command signals S12a to which the ID numbers of all the radio base stations 2 are added are transmitted to all (n) radio transmission station connection units 12
, 12i, ..., 12n. The signal generator 11 may generate the delay measurement command signal S12a at a preset time by controlling the timepiece 13.

The wireless transmission station connection unit 12i receives the delay measurement command signal S12a in the variable delay unit 21. Variable delay unit 21
Sends the delay measurement command signal S12a after delaying it by the delay time Di set by the delay time setting signal S23 from the CPU (control unit) 25. This delay time Di may be any time as an initial value. The variable delay unit 21 transmits / receives the delay measurement command signal S21a obtained by delaying the delay measurement command signal S12a by the delay time Di (SIO (serial I / O)).
O) 22. The transmission / reception SIO 22 receives the delay measurement command signal S21a, the delay measurement command signal S24a adapted to the interface of the CPU 25, and the delay measurement command signal S2.
The delay measurement command signal S22m, which is the same signal as 1a, is generated.

The delay measurement command signal S24a is supplied to the CPU 25, and the delay measurement command signal S22m is sent to the modem (M /
D) 23 is supplied. If the delay measurement command signal S24a has the destination of the number of the wireless transmission station 2i stored in the memory 26 in advance or is a simultaneous measurement command, the CPU 25 activates the timer 24 at this time t1 to transmit the signal. Start measuring the time Ti. Also, the delay measurement command signal S
22m is modulated by the modem 23 and the delay measurement command signal S1
m, and the delay measurement command signal S1m is converted into the line transmission line 4
It is supplied to the wireless transmission station 30i of the wireless transmission station 2i through i.

The delay measurement command signal S1m is transmitted to the wireless transmission station 30.
The return signal S1r returned by i is input from the line transmission line 4i to the modem 23 of the wireless transmission station connection unit 12i. The modem 23 demodulates the return signal S1r to generate a return signal S22r, and the signal S22r is transmitted and received.
It is supplied to IO22. The transmission / reception SIO 22 generates a return signal S24b suitable for the interface of the CPU 25 from the return signal S22r, which is the signal S24b.
26.

CPU 26 during measurement of signal transmission time Ti
Stops the timer 25 at the time t2 when the return signal S24b is received, and receives the signal transmission time Ti from the timer 25, which is the elapsed time from the start time t1 to the stop time t2. As described above, the CPU 26 sends the delay measurement command signal S1m from the wireless transmission station connection unit 12i to the line transmission line 4i.
Signal transmission time T until the return signal S1r is received from the wireless transmission station 2i via the line transmission path 4i.
Measure i. When the delay measurement command signal S12a sent from the signal generation unit 11 is a simultaneous measurement command, the measurement of the signal transmission time Ti is executed by all the wireless transmission station connection units 2a to 2n.

On the other hand, all the wireless transmission station connection units 12 receive the wireless signals S from all the wireless transmission stations 30 after the reference delay time T0 seconds has elapsed since the predetermined signal was transmitted from the signal generation unit 11.
In order to transmit 2, the reference delay value T0 is stored in the memory 26 in advance. The CPU 25 sets the delay time Di to Di =
It is calculated as (T0-Ti / 2), and this delay time Di is updated and set in the variable delay unit 21. The reference delay value T
0 corrects the transmission time of the predetermined signal from the line switching unit of the wireless transmission station connection unit 12i other than the variable delay unit 21 and the wireless transmission station 30i to the transmission antenna. Further, each CPU 25 of the wireless transmission station connection unit 12 stores the delay time Di in the memory 26, and the delay time D
i is reported to the central office control unit 10 by the delay time report S13e. The central station control unit 10 stores the delay time Di reported from each of the wireless transmission station connection units 2 in the memory 10a.
To memorize.

Therefore, each of the radio base stations 2 in the present embodiment can transmit the radio signal S2 all together T0 seconds after the signal generation unit 11 of the central station 1 transmits the above-mentioned predetermined signal. Therefore, it becomes possible to synchronize the respective transmission signal timings of the radio signal S2 transmitted to the service area of the mobile communication system of the present embodiment.

FIG. 4 is a block diagram of the wireless transmission station 30i with the built-in wireless base station 2i used in the embodiment of FIG. Further, FIG. 5 shows the line switching unit 3 used in the wireless transmission station 30i.
It is a figure which shows the state transition of 2, and (a) has shown the switching state when delay time measurement is not being performed, and (b) is showing the delay time measurement.

The operation of the wireless transmission station 30i at the time of measuring and adjusting the delay time between the central station 1 and the wireless base station 2i will be described below.

Radio transmission station 30i through line transmission line 4i
The delay measurement command signal S1m passed to the modem is a modem (M / D)
The delay measurement command signal S demodulated by 23 and demodulated
31 is passed to the line switching unit 41. Here, during normal processing, the line switching unit 41 receives the received signal (that is, the delay measurement command signal S31 as shown in FIG. 5A).
= S33 and the above predetermined signal) are passed to the transmission unit 33 and the reception SIO 43. When the received signal is the predetermined signal, the transmission unit 33 converts the predetermined signal S38 into a radio signal and supplies the radio signal to the transmission antenna 34, and the transmission antenna 33 generates the radio signal S2i from the central office 1. Part 11
Will be transmitted T0 seconds after the above predetermined signal is transmitted.

The reception SIO 35 receives the delay measurement command signal S3.
3 generates a delay measurement command signal S36 which is interface compatible with the CPU 37, and supplies this signal S36 to the CPU (control unit) 37. The CPU 37 decodes the delay measurement command signal S36, and if the ID number given to the signal S36 matches the ID number of the wireless transmission station 2i stored in the memory 38, or if the signal S36 is a simultaneous measurement command,
The line switching unit 32 is controlled by the control command S35 as shown in FIG.
To the state shown in FIG. 5B. As a result, the delay measurement command signal S31 is looped back by the line switching unit 32 to become the loopback signal S32, and the delay measurement command signal S31 is also returned.
The transmission of the radio signal due to 1 from the transmission antenna 34 is blocked. The return signal S32 is modulated by the modem 23 and becomes a return signal S1r. The loopback signal S1r loops back through the line transmission path 4i and is returned to the wireless transmission station connection unit 12i. The CPU 37 uses the delay measurement command signal S36.
When it is confirmed that is addressed to itself, the line switching unit 41 is returned to the state of FIG.

Next, referring to FIGS. 2 and 3, the central office 1
A method for detecting a setting deviation of the delay time Di and recovering it will be described. There are three possible deviations in the setting of the delay time Di.

In the first case, the memory 1 of the central office control unit 10
This is a case where the information of the delay time Di stored in 0a is lost. In this case, the central station control unit 10 sends to the signal generation unit 11 a delay measurement command S11b (that is, a simultaneous measurement command) that orders all the wireless transmission station connection units 12 to measure the signal transmission time Ti at the same time. Send out. When the signal generator 10 receives the signal S11b which is the simultaneous measurement command, it generates a delay measurement command signal S12b corresponding to this command and sends it to all the wireless transmission station connection units 12. Then, similarly to the above, the measurement of the signal transmission time Ti is executed, and the central station control unit 10 receives the delay time Di from all the wireless transmission station connection units 12, whereby the wireless signal S2 transmitted from the wireless base station 2 is received. Transmission timing synchronization is achieved.

The second case is a case where the information of the delay time Di stored in the memory 26 of the wireless transmission station connection unit 12i is lost. In this case, the wireless transmission station connection unit 12i notifies the central station control unit 10 by the report signal S13e that the information of the delay time Di set in the variable delay unit 21 of itself has been lost.
Report to. Then, the central station control unit 10 specifies the delay measurement command S11b specifying the ID number of the corresponding radio base station 2i.
Is output to the signal generator 10. The signal generation unit 11 generates a delay measurement command signal S12b designating the ID number of the wireless base station 2i according to this command S11b and sends it to the wireless transmission station connection unit 12i. Then, the delay time Di measurement is executed, and the central office control unit 10 receives the delay time Di from the measured and executed wireless transmission station connection unit 12i, whereby the transmission timing synchronization of the wireless signal S2 is achieved.

In the third case, the memory 1 of the central control unit 10
0a and the delay time Di stored in the wireless transmission station connection unit 12
This is a case where the delay times Di stored in the memory 26 of i and i are different from each other. The central office control unit 10 sends a delay time report command S13r to each of the wireless transmission station connection units 2 at fixed time intervals, and requests each of the wireless transmission station connection units 2 to present the delay time Di. Each of the connections 2 has a report signal S
The delay time Di is reported to the central office control unit 10 by 13e. The central office control unit 10 compares the information on the reported delay time Di with the information on the delay time Di that it has. If there is no difference in all information, the central station control unit 1
0 takes no action. When the first difference is found in the information of the delay time Di, the central office control unit 10 continues the comparison of the delay time Di. If there is only one difference, the central station control unit 10 outputs to the signal generation unit 11 an individual measurement command S11b of the signal transmission time Ti for the wireless base station 2i in which the difference is found. If the second difference is found in the delay time Di, the central station control unit 10 outputs the simultaneous measurement command S11b to the signal generation unit 11 without further comparison at that time.

In other cases, it is possible to process as the above three complex events.

FIG. 6 shows the delay time D according to the embodiment of FIG.
It is a figure for demonstrating the delay time measurement process corresponding to the memory loss state of i.

FIG. 6 shows that the wireless transmission station 2 has 2a, 2i and 2
The processes of detecting and measuring the delay time Di in the case of three stations of n are summarized. When the central station control unit 10 loses data, the storage state of the delay time Di in each of the wireless transmission station connection units 12 may be any state.
Moreover, the information loss of the delay time Di of the wireless transmission station connection unit 12 cannot occur at two stations at the same time. Furthermore, when comparing the delay times Di, the state of the wireless transmission station connection unit 12 is treated as if it is different.

As described above, if the delay time Di is simultaneously measured, the central office control unit 10 will be temporarily loaded due to this reporting process.
By performing the update processing of the delay time Di in each of the two cases, the signal processing load on the central station 1 is reduced.

[0042]

As described above, according to the present invention, the central station sets the predetermined signal designating the destination radio base station among the plurality of radio base stations and the delay measurement command signal to the corresponding line transmission path. Each of the radio base stations is delayed by a set delay time and then sent out, and a return signal from each of the radio base stations is received via the line transmission path, and the line of the delay measurement command signal is received. The signal transmission time from the supply to the transmission path to the reception of the return signal is measured for each of the radio base stations, so that the transmission timing of the radio signal transmitted from each of the radio base stations is synchronized, When the delay time is updated based on the measured signal transmission time, and each of the radio base stations receives the delay measurement command signal addressed to itself from the line transmission line, the delay measurement command signal Since it is sent back to the central station via the line transmission line as the return signal, the line transmission line connecting the central station and the radio base station used for delay time measurement for delay time adjustment and the radio base station It is possible to reduce the occupied time of the wireless transmission path used by the wireless communication system and the load on the central station, and to shorten the time during which the wireless signal transmitted from the wireless base station is transmitted with a delay time shift. This has the effect of shortening the time from the occurrence of a delay time difference between wireless signals to the restoration.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a delay time adjustment method for a mobile communication system according to the present invention.

FIG. 2 is a block diagram of a central office 1 used in the embodiment of FIG.

FIG. 3 is a block diagram of a wireless transmission station 12i used in the central office 1 of FIG.

FIG. 4 is a block diagram of a wireless transmission station 30i with a built-in wireless base station 2i used in the embodiment of FIG.

5A and 5B are diagrams showing state transitions of the line switching unit 32 used in the wireless transmission station 30i of FIG. 4, where FIG. 5A shows the delay time measurement and FIG. 4B shows the delay time measurement. The switching state when the switch is on is shown.

FIG. 6 is a diagram for explaining a delay time measuring process corresponding to the state of memory loss of the delay time Di according to the embodiment of FIG.

FIG. 7 is a block diagram showing a mobile communication system for adjusting a delay time according to a conventional technique.

[Explanation of symbols]

 1 Central Station 2a to 2n Radio Base Stations 4a to 4n Line Transmission Line 10 Central Station Control Unit 10a Memory 11 Signal Generation Unit 12a, 12b, 12i, 12n Radio Transmission Station Connection Unit 13 Clock 21 Variable Delay Unit 22 Transmit / Receive SIO Unit 23 Modem (M / D) 24 Timer 25 CPU (Control Unit) 26 Memory 30i Radio Transmission Station (TX) 31 Modem (M / D) 32 Line Switching Unit 33 Transmitting Unit 34 Transmitting Antenna 35 Receiving SIO 36 Transmitting SIO 37 CPU (Controlling Unit) ) 38 memory

Claims (4)

[Claims] 1. A radio base station that is placed in each of a plurality of radio zones and that communicates with a mobile station in the area using radio signals whose transmission timings are synchronized with each other, and each of the radio base stations by a line transmission path. With a central station to connect,
Each of the wireless base stations, in a delay time adjustment method of a mobile communication system for converting a predetermined signal sent from the central station via the line transmission path to the wireless signal and transmitting the signal, the central station A signal transmitting means for delaying and transmitting the predetermined signal designating the destination radio base station and the delay measurement command signal to the corresponding line transmission path by a delay time set for each of the radio base stations, A loopback signal receiving means for receiving a loopback signal from each of the radio base stations via the line transmission path, and a loopback signal by the loopback signal receiving means from the supply of the delay measurement command signal to the line transmission path. Signal transmission time measuring means for measuring the signal transmission time until reception of each of the wireless base stations, and the wireless transmission from each of the wireless base stations A delay time managing means for updating the delay time set in the signal sending means based on the measured signal transmission time so that the signal transmission timings are synchronized, each of the radio base stations, When the delay measuring command signal addressed to itself is received from the line transmission line, the delay measuring command signal is sent back to the central office via the line transmission line as the loopback signal. A delay time adjustment method for communication systems. 2. The central station control means for instructing the central station to generate the delay measurement command signal and the predetermined signal,
The delay measurement command signal and the predetermined signal corresponding to the generation instruction are further generated and supplied to the signal sending means, and the delay time managing means sets the delay set in the signal sending means. The central station control means obtains and stores the set delay time from the delay time management means for all the radio base stations. All storage means, storage information detection means for detecting loss of information of the delay time stored in the individual storage means and the full storage means, and the storage information detection means according to the information loss state of the detected delay time. A delay time measuring station determining unit for instructing generation of the delay measuring command signal including designation of the wireless base station to which the delay measuring command signal is transmitted. Delay time adjustment method of the mobile communication system according to claim 1, symptoms. 3. A radio base station which is placed in each of a plurality of radio zones and communicates with a mobile station in the area using radio signals whose transmission timings are synchronized with each other, and each of the radio base stations by a line transmission path. With a central station to connect,
Each of the wireless base stations, in a delay time adjustment method of a mobile communication system for converting a predetermined signal sent from the central station via the line transmission path to the wireless signal and transmitting the signal, the central station A central station control unit for instructing generation of the predetermined signal and delay measurement command signal designating a destination radio base station; and a signal generation unit for generating the delay measurement command signal and the predetermined signal corresponding to the generation command. , Receiving the delay measurement command signal addressed to itself and the predetermined signal,
For each of the radio base stations that delays these signals by the set delay time and sends them to the connected line transmission path and receives the return signal of the delay measurement command signal via the line transmission path. A wireless transmission station connection unit provided and signal transmission time measuring means for measuring the signal transmission time from the supply of the delay measurement command signal to the line transmission path to the reception of the return signal for each of the wireless base stations. And, so that the transmission timing of the radio signal from each of the radio base stations is synchronized, the delay time set for each of the radio transmission station connection units is based on the measured signal transmission time. Delay time management means for updating, and each of the radio base stations receives the delay measurement command signal addressed to itself from the connected line transmission line, and outputs the delay measurement command signal. A delay time adjusting method for a mobile communication system, comprising: a line switching circuit for sending back to the central station via the line transmission path as the return signal. 4. The delay time management means further comprises an individual storage means for storing the set delay time for each of the radio base stations, and the central station control unit controls all the set delay times. All storage means for obtaining and storing the delay time from the delay time management means; delay time information detection means for detecting loss of information of the delay time stored in the individual storage means and the all storage means; It further comprises: delay time measuring station determining means for determining the radio base station for transmitting the delay measurement command signal according to the state of information loss of the delay time and notifying the signal generating means. Item 3. A delay time adjustment method for a mobile communication system according to Item 3.