JP3052030B2 - Mutual synchronization between base stations linked to the telephone network - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication network system comprising a plurality of base stations and a large number of mobile stations such as portable telephones. Related to each other.

[0002]

2. Description of the Related Art A time division multiple access system (hereinafter, TDMA)
The communication is performed by allocating a plurality of channels obtained by cutting out a time axis into a plurality of blocks that are periodically repeated, to each station. In this TDMA system, it is important that the channels on the time axis allocated in each base station are synchronized. If the synchronization is not established, the timing of the transmission signals from each station overlaps, and Efficiency decreases.

Conventionally, in this type of technology, there is a method of transmitting a synchronization signal from a central station to each base station in a hard manner. However, this method requires a large transmission power and also requires a remote base station and a near base station. There is a problem in that the difference in radio wave propagation time between the base station and another base station becomes a problem, and it is necessary to change the control for each base station in a different system. To solve these problems, there is one disclosed in Japanese Patent Application Laid-Open No. Hei 4-287532. In this method, each base station receives a signal corresponding to a synchronization signal of another base station without installing a central station, and each of the base stations compares the received signal with a transmission signal of its own station. In this method, synchronization between base stations is established in a self-sustained and distributed manner by a method of correcting the synchronization deviation.

[0004]

However, in the above-mentioned autonomous decentralized system, a plurality of receiving devices are required to receive the radio waves of another base station at different timings while maintaining the timing of transmitting its own radio waves. become. In addition, since its own transmission timing is shifted so as to converge the deviation of synchronization, there is a possibility that deviation of synchronization with a mobile station (slave unit) that is talking in synchronization with the base station may occur. . Further, there is a problem that the correction of the transmission timing for achieving the convergence of the synchronization causes a new synchronization deviation, and the deviation of the synchronization causes undulation-like oscillation, and it takes a long time for the convergence of the synchronization.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and in order to eliminate the above-mentioned problems, a base station synchronized with a telephone network for establishing a synchronization relationship by sequentially specifying a base station to be synchronized from a central office. An object of the present invention is to provide a mutual synchronization method.

[0006]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention uses radio in a service area in which a plurality of base stations connected to a telephone network in which a central office for general management is installed are arranged. A mutual synchronization system between base stations linked to a telephone network for mutually synchronizing base stations in a system for performing time division multiple access mobile communication, wherein the base station controls synchronization of a radio signal. And the radio signal
Communication with the central office through the telephone network
To a communication unit, central office through a telephone network a plurality of the specific base station from the base <br/> land station designated as a master base station, the radio signal of the master base station to other base stations in the vicinity To synchronize, and the instructed base station is designated
Received the radio signal of the master base station
Sending synchronization of the radio signals of the own station by the synchronization means, the next central station radio signal by specifying the counterpart synchronization with the base station in the vicinity of the base station with a good of the synchronous synchronization the phases were commanded, the base station which has received the command is specified to take
The radio signal of the hand is received, the radio signal of the own station is synchronized with the radio signal by the synchronizing means, and thereafter, the central station repeatedly repeats the command sequentially through the telephone network in the same manner. It is characterized by synchronizing signals.

[0007]

According to the present invention, by adopting the above structure, the designated base station to be synchronized is designated from the central station, and the designated base station can communicate with the designated base station without externally supplying a hard synchronization signal. To realize synchronization of a plurality of base stations sequentially by receiving a radio wave such as a control radio wave for a normal service of a station and synchronizing with a radio wave of a partner base station by using a synchronizer 1-2. Can be done.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 2 is a diagram showing a telephone system and a calling procedure according to the present invention. As shown in the figure, in this system, a plurality of base stations 25, 26 and 27 are provided in a service area 24, and these base stations are connected via a telephone network 20 to a central office 21 and a switching office 22 which are managed collectively. Is a system for performing wireless telephone communication with a mobile station 28 in a service area 24.

FIG. 1 is a block diagram showing the configuration of a mutual synchronization system between base stations linked to a telephone network according to the present invention.
As shown in the figure, a base station 1 used in the present system includes a control unit 1-1 including a microprocessor and the like, and a synchronizer 1 that synchronizes the transmission and reception timing of the own station with the transmission and reception of radio waves.
2. Transmitter 1-4 for transmitting and receiving radio signals, and receiver 1
-3, a communication interface for connecting to a telephone network
The receiving antenna 2 receives a signal from another base station and transmits a synchronized transmission signal from the antenna 3.

The control unit 1-1 is constituted by a microcomputer or the like and analyzes transmission / reception data of the base station of the synchronization partner and controls the synchronization device 1-2.
This is a device for synchronizing the radio signal transmitted from the own station with the radio signal of the synchronization partner base station received in 3. The receiving unit 1-3 converts the radio wave received by the receiving antenna 2 into reception data at the timing controlled by the synchronizer 1-2, and converts the radio wave into the receiving data.
1 and the transmission unit 1-4 transmits the transmission data from the control unit 1-1.
The signal is converted into a radio wave at the timing controlled by the synchronization device 1-2 and transmitted from the transmission antenna 3. The communication interface 1-5 is for receiving commands from the central office through the telephone network.

The calling procedure will be described with reference to FIG. When dialing the mobile station 28 from a general telephone, the exchange 22 makes a call request a to the central office 21 when dialing. The central office 21 makes a call b to the base stations 25, 26 and 27. The base station 25 in which the mobile station 28 is in its own radio wave area sends a reply c to the central station 21, and the central station 21
The number 5 is sent to the exchange 22. The exchange 22 is connected to the base station 25, and the ordinary telephone 23 can talk to the mobile station 28.

FIG. 3 is a diagram showing communication between a base station and a mobile station using a communication channel. As shown in the figure, in the TDMA system, a channel has a transmission frame and a reception frame of 2.5 ms.
Each frame is divided into four slots. The transmitting and receiving frames are synchronized,
Communication can be performed using one slot. In the example of FIG. 3, multiplex communication of four calls is possible using one frequency.

Therefore, it is, of course, necessary to synchronize the transmission and reception frames of the base station and the mobile station. However, as shown in FIG. 2, a plurality of base stations 25 and 2 are located in the same service area 24.
Since 6 and 27 are installed and communicate with mobile stations on the same frequency,
It is necessary to synchronize transmission and reception frames between a plurality of base stations in the service area. For this reason,
Synchronous control is performed using a control channel that is constantly transmitted during normal service.

FIG. 4 is a diagram showing a configuration of slots of a control channel and a communication channel. As shown in the figure, the control slot is a transient response ramp time R of 4 bits, a start symbol SS of 2 bits, and a preamble P of 62 bits.
R, a 32-bit synchronization word UW, and a 124-bit control signal CAC, which are used to allocate communication channels to mobile stations. Further, since the control signal CAC includes the ID number of the base station, the receiving station can determine the source base station.

FIG. 5 is a diagram showing a flow of synchronization of a base station in a service area. Description will be made with reference to FIG. As described above, the central station for overall management selects one base station A from the service area # 1 via the telephone network and designates it as the master base station. Next, it instructs the base stations B and C to synchronize with the base station A.

FIG. 6 is a diagram showing a method in which the slave base station performs frame synchronization with the master base station. As shown in the figure, the slave base stations B and C each receive the radio wave from the master base station A at the receiving section, confirm the control channel signal at the control section, and determine the offset time by the synchronizer (see FIG. 1). It adjusts the transmission timing of its own station, and synchronizes the frame with the master-base station A and transmits it.

Similarly, the central station instructs the base stations D and E to synchronize with the base station B, and further instructs the base stations F and G to synchronize with the base station C. In this way, the server
The base stations A to G in the service area # 1 can be synchronized around the master-base station A.

Similarly, the service area # 2 is synchronized around the master base station H. Here, it is possible to easily change or integrate the service areas. For example, when the base station G and the base station K in FIG. 5 cause interference due to being close, the service areas # 1 and # 2 are integrated. Then, the synchronization within the service area can be maintained by re-starting from the designation of the master base station and re-establishing the synchronization.

FIG. 7 is a diagram showing the arrangement of base stations in the service area and the flow of synchronization. The central station designates a base station near the center of the service area as the master base station # 1, designates a base station within a radio wave reach centered on the base station as the slave base station, and instructs it to synchronize. . Thereafter, by sequentially instructing each base station to synchronize with the other base station, all the master base stations # 1 to slave base stations # 1 in the service area are provided.
3-7 can be synchronized.

[0020]

As described above, according to the present invention, the following excellent effects are expected. (1) By designating a partner base station to be synchronized from the central station, the designated base station can be used for control of the partner station for normal services without the supply of a hard synchronization signal from the outside. By receiving a radio wave such as a radio wave and synchronizing with a radio wave of a partner base station using a synchronization device, synchronization of a plurality of base stations can be realized sequentially.

(2) Since there is only one partner base station for synchronizing, the receiving device only needs to perform reception at one timing, and can be shared with the transmitting device of the normal service. The internal configuration is simplified.

[0022] (3) After that there is a time synchronization, there is no worry of the out-of-sync with the mobile station for the synchronization does not vary significantly during normal service.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a mutual synchronization system between base stations linked to a telephone network according to the present invention.

FIG. 2 is a diagram showing a telephone system and a calling procedure of the present invention.

FIG. 3 is a diagram illustrating communication between a base station and a mobile station using a communication channel.

FIG. 4 is a diagram illustrating a configuration of slots of a control channel and a communication channel.

FIG. 5 is a diagram showing a flow of synchronization of a base station in a service area.

FIG. 6 is a diagram illustrating a method of acquiring frame synchronization between base stations.

FIG. 7 is a diagram showing an arrangement of base stations in a service area and a flow of synchronization.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base station 1-1 Control part 1-2 Synchronization device 1-3 Receiving part 1-4 Transmitting part 1-5 Communication interface 2 Receiving antenna 3 Transmitting antenna 20 Telephone network 21 Central station 22 Switching station 23 General telephone 24 -Service area 25 Base station 26 Base station 27 Base station 28 Mobile station

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H04B 7/26 H04Q ⁷ /00-7/38

Claims (1)

(57) [Claims] 1. A base station in a system for performing time-division multiple access mobile communication using radio within a service area in which a plurality of base stations connected to a telephone network in which a central office for general management is installed are arranged. A mutual synchronization method between base stations linked to a telephone network that mutually synchronizes the stations, wherein the base station controls synchronization of a radio signal,
And receiving means for transmitting and receiving radio signals, a communication means for communicating with the medium <br/> Hisashikyoku through the telephone network, specifying a particular base station as the master base station wherein the central station from the plurality of base stations through the telephone network and to instruct the synchronization with respect to other base stations in the vicinity in the radio signal of the master base station, the commanded base stations is designated master
Sending synchronization of the radio signals of the own station by the synchronization means in the radio wave signal receiving radio signals over the base station, then the central station to the base station in the vicinity of the base station with a good of the synchronous Instructs to synchronize the radio signal by designating the partner to be synchronized, and the base station receiving the command transmits the radio signal of the designated partner.
Receiving the radio signal and synchronizing the radio signal of the own station with the synchronizing means, and thereafter, the central station repeats the command sequentially through the telephone network in the same manner to synchronize the radio signal of all the base stations. A method of mutual synchronization between base stations linked to a telephone network.