JP2526803B2 - Radio base station synchronization method and mobile communication system - Google Patents

Abstract

PURPOSE:To establish the synchronization of radio frames among plural radio base stations in a short time. CONSTITUTION:When a mobile machine 50-1 communicates with the radio base station 10-1 adjacent to the radio base station 10-2, the radio base station 10-2 receives transmission signals from the mobile machine 50-1 and measures the delay amount d1 of reception signals in a delay detection circuit. Similarly, when the radio base station 10-(n-1) communicates with the mobile machine 50-(n-1) the radio base station 10-n receives the transmission signals from the mobile machine 50-(n-1) and measures the delay amount d(n-1) of the reception signals. A delay amount set value is calculated by a delay amount arithmetic circuit 15 based on the obtained delay amount. When a clock 16 reaches the predetermined time, the delay amount d1 is transmitted to the radio base station 10-2, the delay amount (d1-d2) is transmitted to the radio base station 10-3 and (d1-d2...d(n-1)) is transmitted to the radio base station 10-n by a delay amount set signal transmission circuit 15.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a plurality of radio base stations,
It is composed of a radio exchange station which is connected to each of these radio base stations via a communication line, and a plurality of mobile devices which communicate via time division multiplex radio lines within the radio service area of these radio base stations. Mobile communication system.

[0002]

2. Description of the Related Art Conventionally, as a radio base station synchronization method for synchronizing the transmission timing to a mobile unit between radio base stations, all radio base stations receive a transmission signal transmitted from an adjacent radio base station. Has a dedicated receiver, one is the reference station, the other is the adjustment station, the adjustment station receives the radio signal sent from the reference station, establishes synchronization between the radio base stations,
Since then, a method has been known in which a plurality of radio base stations are phase-dependently adjusted. As another method, as shown in FIG. 6, a reference signal for establishing synchronization between wireless base stations is transmitted from the reference base station 41, and the wireless base station 40-2 causes the wireless base station 40-2 to adjoin the adjacent wireless base station 40-1. The radio base station 40-2 subordinately adjusts the radio frame signal to be transmitted to the mobile device 50 by receiving the signal from the mobile device 50 communicating with the mobile device 50 and measuring the time difference between the received signal and the reference signal. The method of doing is also proposed.

[0003]

The above-mentioned conventional method for establishing synchronization between radio base stations is for establishing synchronization between radio base stations.
One serves as a reference station and the other serves as a coordinating station, and the coordinating station receives a radio signal from the reference station and establishes synchronization between the radio base stations. In the case of such a method, for example, as shown in FIG. 6, when the readjustment of the synchronization between the radio base stations 40-1 and 40-2 in a system in which a plurality of radio base stations are subordinately installed , Radio base station 40-
There is a need to readjust the synchronization between Nos. 2 and 40-3, and thereafter, it becomes necessary to readjust the synchronization between the radio base stations in a dependent manner. In such a case, it takes a considerable amount of time to complete the synchronization readjustment between all the wireless base stations, and it is necessary to perform the synchronization adjustment between the wireless base stations regardless of the time zone when the communication call volume is high. . Therefore, when the wireless base station and the mobile device are communicating, if the wireless base station suddenly adjusts the phase synchronization,
The time position of the signal received by the mobile device may be momentarily shifted, and the communication between the mobile device and the wireless base station may be interrupted momentarily.

An object of the present invention is to provide a mobile communication system for establishing radio frame synchronization between a plurality of radio base stations in a short time.

[0005]

According to the inter-radio base station synchronization method of the present invention, a radio base station receives a signal from a mobile station communicating with an adjacent radio base station and determines the delay amount of the received signal. The relative delay amount difference to the reference wireless base station is calculated from the delay amounts thus obtained between the adjacent wireless base stations, and the relative delay amount difference is set to the delay amount set value for each wireless base station. At a predetermined time, the wireless switching center sends the delay amount set value to each wireless base station almost simultaneously as a delay time signal for adjusting the cycle between the wireless base stations.

In the mobile communication system of the present invention, at least one radio base station among a plurality of radio base stations is defined as a reference station, and the first radio base station is used by an adjacent second radio base station. At least one wireless signal receiving unit capable of setting at least one of the existing wireless channels; a delay amount detecting unit detecting a delay amount of a received signal from the mobile device;
And a sending time adjusting means for adjusting a sending time of a wireless frame transmission signal sent from the wireless base station to the mobile device, wherein the wireless switching center is a synchronization signal serving as a reference for synchronizing a plurality of wireless stations. A synchronization signal generating means, a delay amount receiving means for receiving output signals of the delay amount detecting means of the plurality of wireless base stations, a time counting means, and a delay amount detecting means received from the plurality of wireless base stations. Based on the output signal of the above, the delay amount calculation means for calculating the relative delay amount difference with the reference station, and the calculation result of the relative delay amount difference to each radio base station at a predetermined time by the output of the time counting means. It is characterized in that it has a delay amount setting signal transmitting means for transmitting.

[0007]

The radio base station receives a signal from a mobile station communicating with an adjacent radio base station and measures the delay amount of the received signal. In this way, the relative delay amount difference from the reference wireless base station is obtained from the delay amounts obtained between the adjacent wireless base stations, and this relative delay amount difference is set as the delay amount set value for each wireless base station. . When the predetermined time arrives, the wireless switching center sends a delay time signal (delay amount set value) for synchronization adjustment between the wireless base stations to the respective wireless base stations almost at the same time. Therefore, the phase synchronization between the radio base stations can be established in a short time, and the phase can be adjusted during a time period when the call volume is low, and the interference to the line during communication between the mobile station and the radio base station can be minimized. be able to.

[0008]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a block diagram of a mobile communication system according to an embodiment of the present invention, and FIG. 2 is radio base stations 10-1, 10-2 ,.
, 10-n is a block diagram.

This mobile communication system uses a radio base station 10-
1, 10-2, 10-3, ..., 10-n, a wireless switching center 11 connected to each of these wireless base stations 10-1 to 10-n via a communication line, and these wireless stations. Mobile stations 50-1, 5 that perform communication via time division multiplex wireless lines within the wireless service areas of the base stations 10-1 to 10-n.
0-2, 50-3, ... The wireless switching center 11 is connected to a wireless frame synchronization signal transmission circuit 12, a delay amount storage circuit 13, a delay amount calculation circuit 14, a delay amount setting signal transmission circuit 15 and a clock 16. The wireless switching center 11 includes wireless base stations 10-1, 10-2, 10-3, ...
., 10-n and communication lines, respectively. The radio frame synchronization signal transmission circuit 12 transmits a radio frame synchronization signal which serves as a reference for synchronizing a plurality of radio base stations. The delay amount storage circuit 13 includes radio base stations 10-1 to 10-1.
The delay amount signal sent from 0-n is stored. The delay amount calculation circuit 14 performs a calculation process based on the delay amount signals received from the plurality of radio base stations stored in the delay amount storage circuit 13 to obtain the delay amounts of the respective radio base stations 10-1 to 10-n. Ask for. The delay amount setting signal transmission circuit 15 causes the radio base stations 10-1 to 10-10 to operate when the clock 16 reaches a predetermined time.
Send the delay amount setting signal to -n.

Next, the radio base stations 10-1 to 10-n will be described. The multiplexing / demultiplexing circuit 34 is connected to the wireless switching center 11 via a communication line, separates a signal (primary group interface signal) transmitted from the wireless switching center 11 and outputs a wireless frame synchronization signal to the wireless frame receiving circuit 31. ,
The 64 Kbps signal is output to the transceivers 20-1 to 20-m, the delay amount setting signal is output to the delay amount setting circuit 33, and the 64 Kbps transmitted from the transceivers 20-1 to 20-m.
A signal is input, converted into a primary group interface signal, and transmitted to the wireless switching center 11. The radio frame reception circuit 31 extracts a radio frame synchronization signal. The delay circuit 32 delays the radio frame synchronization signal extracted by the radio frame receiving circuit 31 by a fixed time set in the delay amount setting circuit 33, and outputs the signal to the transceivers 20-1 to 20-m.

Next, the transceivers 20-1 to 20-m will be described. The receiver 21 receives a signal from the mobile device. The decoder 22 performs decoding processing such as error correction on the signal from the mobile device, and the synchronization detection circuit 23 and the signal control circuit 2
Output to 7. The synchronization detection circuit 23 detects the synchronization signal included in the received signal. The TDM timing generation circuit 26 generates a timing signal for processing the radio frame synchronization signal output from the delay circuit 32, and the signal control circuit 2
7 and the delay detection circuit 24. Delay detection circuit 24
Detects the time difference between the wireless frame synchronization signal sent from the wireless switching center 11 and the received signal sent from the mobile device. The signal control circuit 27 outputs the output of the decoder 22 to 64K.
It is converted into a bps signal and sent to the multiplexing / demultiplexing circuit 34, and a 64 Kbps signal from the multiplexing / demultiplexing circuit 34 is input and converted into a radio frame signal. The encoder 26 adds an FEC check bit or the like to the radio frame synchronization signal.
The transmitter 25 modulates the output of the encoder 26 and then sends it to the mobile device.

Next, the operation of this embodiment will be described.
First, the wireless frame synchronization signals are transmitted from the wireless frame synchronization signal transmission circuit 12 connected to the wireless switching center 11 so that the wireless frame synchronization can be established among the plurality of wireless base stations 10-1 to 10-n. Sent to. FIG. 3 shows an interface between the wireless switching center 11 and the wireless base station 1.
The next group transmission line is shown. The radio frame synchronization signal is transmitted using the 8th bit (MF) of the time slot TS1, and the MF bit is set or reset at a constant cycle. In FIG. 2, the primary group digital signal from the wireless switching center 11 is demultiplexed into time slots by the multiplexing / demultiplexing circuit 34, and the wireless frame receiving circuit 31 causes the wireless switching center 1
The radio frame synchronization signal from 1 is extracted. The radio frame synchronization signal sent from the radio frame receiving circuit 31 is delayed by the delay circuit 32 for a predetermined time, and the transceiver 20-
1 to 20-m. The delay amount setting circuit 33 receives the delay amount setting signal sent from the delay amount setting signal sending circuit 15, controls the delay circuit 32, and outputs the radio frame synchronization signal output from the radio frame receiving circuit 31 for a predetermined time. Delay.

The operation of the transceiver 20-1 of FIG. 2 will be described in detail. The signal from the mobile device is received by the receiver 21 and demodulated, then decoded by the decoder 22 such as error correction, converted into a 64 Kbps signal by the signal control circuit 27 and input to the multiplexing / demultiplexing circuit 34. It is converted to a primary group interface signal and sent to the wireless switching center 11. On the other hand, the communication signal from the wireless switching center 11 is input to the demultiplexing / demultiplexing circuit 34 as a primary group interface signal, and 64 Kbp.
The signal is converted into an s signal, input to the signal control circuit 27, converted into a radio frame signal, further added with an FEC check bit or the like by the encoder 26, modulated by the transmitter 25, and then transmitted to the mobile device. In the delay circuit 32, the delay amount setting circuit 3
The TDM timing generation circuit 28 generates a timing signal for generating a radio frame, and the radio frame synchronization signal delayed by the time designated by 3 is supplied to the signal control circuit 27 and input to the delay detection circuit 24. ing. If the radio channel used in the adjacent radio base station is set in the receiver 21 in advance, the receiver 21 receives the transmission signal from the mobile station communicating in the service area of the adjacent radio base station. can do. The signal from the mobile device is decoded by the decoder 22, the synchronization signal included in the received signal is detected by the synchronization detection circuit 23, and the output of the synchronization detection circuit 23 is input to the delay detection circuit 24. The delay detection circuit 24 detects the time difference between the wireless frame synchronization signal transmitted from the wireless switching center 11 and the synchronization signal transmitted from the mobile device. This time difference signal (delay amount signal) passes through the signal control circuit 27 and the wireless switching center 1
Sent to 1.

FIG. 4 shows a radio frame used between a radio base station and a mobile device. Upon receiving the signal T1 from the wireless base station, the mobile device sends the signal T1 at the reception timing R1 of the wireless base station after Tx time. The mobile device adjusts the time Tx so that the reception timing R1 of the radio base station is accurately timed. In the radio base station, the relationship between the signal transmission time to the mobile device and the signal reception time from the mobile device is generated by the TDM timing generation circuit 28 of FIG. For example, the wireless base station 10-1 and the mobile device 50-1
The mobile device 50-1 adjusts the time Tx during communication, so that the radio base station 10-1 and the mobile device 50-1 are synchronized. Further, since the distance between the wireless base station 10-1 and the wireless base station 10-2 is different from the wireless exchange station 11 and the reception timing of the wireless frame synchronization signal is different, the wireless base station 10-1 communicates with the wireless base station 10-1. Mobile 5
The signal transmission timing of 0-1 does not match the reception timing of the wireless base station 10-2. This state shows a state in which the radio base stations 10-1 and 10-2 are not synchronized with each other.

FIG. 5 shows the time relationship of the radio frame synchronization signals from the radio switching center 11. Since the distance between the wireless switching center 11 and the wireless base stations 10-1 and 10-2 is different, the reception time of the wireless frame synchronization signal transmitted from the wireless switching center 111 is different. The radio base stations 10-1 to 10-n transmit the radio frame signal in synchronization with the radio frame synchronization signal. The radio base station 10-2 adjusts the radio channel of the receiver 21 to the radio channel used by the radio base station 10-1 to establish synchronization with the radio base station 10-1, and the radio base station 10- 1 receives the signal from the mobile device 50 among the communication signals between the mobile device 50 and the mobile device 50 so that the received signal from the mobile device 50 matches the reception timing of the wireless base station 10-1. Adjust the timing of. As a result, the time position of the time slot T1 of the radio base station 10-1 and the time position of the time slot T1 of the radio base station 10-2 come to coincide with each other.

The delay amount signal transmitted from the wireless base station is input to the delay amount storage circuit 13 via the wireless switching center 11. In this way, the delay amount signals from the plurality of radio base stations are stored in the delay amount storage circuit 13. The delay amount calculation circuit 14 performs a calculation process based on the delay amount signals received from the plurality of radio base stations stored in the delay amount storage circuit 13 to obtain the delay amount of each radio base station. The transmission circuit 15 transmits the calculated delay amount to each radio base station. That is, the delay amount calculation circuit 14 determines that the wireless base station 10
The delay amount d1 between the radio base stations 10-1 and 10-2 is obtained using -1 as the reference station. Similarly, the radio base stations 10-2 and 1
0-3 delay amount d2, ..., Radio base station 10- (n
The delay amount between -1) and 10-n can be obtained as d (n-1). Therefore, d1 for the radio base station 10-2 and (d1-d2) for the radio base station 10-3.
, ..., for the radio base station 10-n, (d1-d
2 -... d (n-1)) is obtained as the delay amount set value. The delay amount setting signal transmitting circuit 15 sets these delay amount setting values when the clock 16 reaches a predetermined time.
It transmits to each radio base station almost at the same time. The wireless base station multiplexes / demultiplexes the delay amount setting signal from the wireless switching center 11
It is received by the delay amount setting circuit 33 via 4 and the delay setting amount is input to the delay circuit 32. As a result, the output (radio frame synchronization signal) of the radio frame receiving circuit 31 is delayed by the delay circuit 32.
Is delayed for a predetermined time and input to the TDM timing generation circuit 28. The timing of the radio frame signal is T
Since it is generated by the DM timing generation circuit 28, the wireless frame to the mobile device is adjusted and the phase of the wireless frame between the wireless base stations is adjusted.

As described above, according to this embodiment,
The phase difference between adjacent radio stations is measured, the relative delay time with the reference radio base station is calculated from the measurement results, and this result is set to each radio base station, so phase adjustment between radio base stations Can be done in a short time.

[0019]

As described above, according to the present invention, a radio base station receives a signal from a mobile station communicating with an adjacent radio base station and measures the delay amount of the received signal. Then, the relative delay amount difference with the reference wireless base station is obtained from the delay amount obtained between the adjacent wireless base stations, and this relative delay amount difference is set as the delay amount set value for each wireless base station, and the wireless exchange station When a predetermined time comes, by sending a delay time signal (delay amount setting value) for synchronization adjustment between the radio base stations to each radio base station almost at the same time,
Phase synchronization between the radio exchanges can be established in a short time, and the phase can be adjusted during periods of low call volume, minimizing interference with the line during communication between the mobile station and the radio exchange. There is an effect that can be done.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a mobile communication system according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of radio base stations 10-1 to 10-n.

FIG. 3 is a format diagram of a signal used between a wireless switching center 11 and a wireless base station.

FIG. 4 is a time relationship diagram of signal transmission / reception between a wireless base station and a mobile device.

FIG. 5 is a time relationship diagram of radio frame synchronization signals.

FIG. 6 is a configuration diagram of a conventional example of a mobile communication system.

[Explanation of symbols]

 10-1 to 10-n Radio base station 11 Radio exchange station 12 Radio frame synchronization signal transmission circuit 13 Delay amount storage circuit 14 Delay amount calculation circuit 15 Delay amount setting signal transmission circuit 16 Clock 21 Receiver 22 Decoder 23 Synchronization detection circuit 24 Delay Detection Circuit 25 Transmitter 26 Encoder 27 Signal Control Circuit 31 Radio Frame Reception Circuit 32 Delay Circuit 33 Delay Amount Setting Circuit 34 Multiplexing / Demultiplexing Circuit 40-1 to 40-m Radio Base Station 41 Reference Base Station 42 Radio Base Station Control device 50-1, 50-2, 50-3 Mobile device

Claims (2)

(57) [Claims] 1. A plurality of radio base stations, a radio exchange station connected to each of these radio base stations via a communication line, and a time division multiplex radio line within a radio service area of these radio base stations. In a mobile communication system composed of a plurality of mobile devices that perform communication, a wireless base station receives a signal from a mobile device that is communicating with an adjacent wireless base station, and measures the delay amount of the received signal,
In this way, the relative delay amount difference to the reference wireless base station is obtained from the delay amounts obtained between the adjacent wireless base stations, and the relative delay amount difference is set as the delay amount set value for each wireless base station, The wireless switching center is a method for synchronizing between wireless base stations, which, at a predetermined time, sends the delay amount set value to each wireless base station almost simultaneously as a delay time signal for synchronization adjustment between the wireless base stations. 2. A plurality of radio base stations, a radio exchange station connected to each of these radio base stations via a communication line, and a time division multiplex radio line within a radio service area of these radio base stations. In a mobile communication system configured with a plurality of mobile devices that perform communication, at least one radio base station among a plurality of radio base stations is defined as a reference station, and the first radio base station is an adjacent second radio. At least one radio signal receiving means capable of setting at least one of the radio channels used in the base station, delay amount detecting means for detecting the delay amount of the received signal from the mobile device, and first radio base station From the mobile station to the mobile station, the radio switching center adjusts the transmission time of the radio frame transmission signal, and the wireless switching center is configured to generate a synchronization signal serving as a reference for synchronizing a plurality of wireless stations. A signal generating means, a delay amount receiving means for receiving output signals of the delay amount detecting means of the plurality of wireless base stations, a time counting means, and an output signal of the delay amount detecting means received from the plurality of wireless base stations. Originally,
A delay amount calculating means for calculating a relative delay amount difference with respect to the reference station, and a delay amount setting signal for transmitting a calculation result of the relative delay amount difference to each radio base station at a predetermined time by the output of the time counting means. A mobile communication system having a sending means.