JP2003087175A - Radio station communication mesh system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio station communication mesh system capable of easily performing time synchronization between radio stations. SOLUTION: In this radio station communication mesh system, a time synchronizing reference radio station 10, having a GPS receiver and synchronizing with a UTC (coordinated universal time), makes radio stations A 11 to 14 connected to the time synchronization reference radio station 10 through a radio transmission path, calculates the time error from conventional time information through radio communication and establishes time synchronization. The radio stations A 11 to A 14 which have established synchronization further apply synchronization establishment based on the time information of the radio stations A 11 to A 14 to radio stations B 15 to 18 which are connected through a radio transmission line and in which synchronization has not been established, before.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a mesh type wireless station communication system in which wireless stations are arranged in a mesh type,
In particular, the present invention relates to a mesh type wireless station communication system capable of easily performing highly accurate time synchronization between wireless stations.

[0002]

2. Description of the Related Art In a wireless station communication system composed of a plurality of wireless stations, it is necessary for communication to establish synchronization between wireless stations. In particular, it is necessary that synchronization be established between the base stations in the radio calling method during simultaneous transmission at the same frequency, and in the mobile phone method during handover or base station identification.

A method of establishing synchronization in a conventional radio station communication system will be described with reference to FIGS. 7 and 8. Figure 7
8 and 9 are diagrams showing a synchronization method in a conventional radio station communication system, FIG. 7 is a radio paging system which is a star type radio communication system, and FIG.
CDMA (Narrow-band Code Division Multiple Acces
s) It shows a synchronization method in a mobile phone system in a communication system.

First, a method for establishing synchronization using a wired transmission path will be described with reference to FIG. In FIG. 7, the base stations 71 to 74 have a function of transmitting a calling signal to the mobile stations 75 to 77, and the mobile stations 75 to 77 have only a function of receiving the calling signal. Further, the central station 70 is connected to each base station by a wired transmission line and a wireless transmission line,
It communicates with each base station. In FIG. 7, solid arrows indicate wired transmission lines, and broken arrows indicate wireless transmission lines.

In the radio paging communication system, the base stations 71 to 71
Since the 74 transmits the call signal at the same frequency to the mobile stations 75 to 77, it is necessary to make the transmission timing of the call signal uniform in each base station. In the wireless station communication system of FIG. 7, each base station receives a signal transmitted from the central station 70 via the wired transmission path and the wireless transmission path, extracts the reception timing of each transmission path, and obtains the time difference between them. Is corrected by the own delay circuit. By performing such control, the radio signal transmission timing from the base stations 71 to 74 to the mobile stations 75 to 77 is aligned with the radio signal transmission timing in the central station 70, and synchronization between the base stations is established. .

Next, GPS (Global Positioning System)
A synchronization establishment method using m) will be described with reference to FIG. Here, time synchronization using GPS will be briefly described. GPS satellites are equipped with atomic clocks such as cesium and rubidium, and UTC at 6 o'clock on January 6, 1980 UTC.
The GPS time has started in synchronization with (Coordinated Universal Time). 198 GPS satellites
The number of weeks from 0:00 on January 6, 0 to the reception time, the reference time of the orbital element (the number of seconds from 0:00), the GPS time correction parameter, and the time synchronization pattern are two frequencies 1575 called L band by radio waves. .42 MHz (L1), 12
It is transmitting at 27.60 MHz (L2). The GPS receiver uses this information to synchronize the time with the satellite clock. Currently available GPS receivers are UTC
Since it is possible to obtain the pulse signal (clock signal) and the time information per second synchronized within about ± 100 ns, it can be an effective means for base station synchronization.

On the other hand, in an N-CDMA communication system, a base station is identified by a pilot PN (Pseudorandom Noi).
se) Because the phase offset of the sequence is used, the phase offset cannot be specified unless the base stations are synchronized in time, and the base stations cannot be identified. Will be needed. In addition, since radio waves of the same frequency are transmitted from multiple base stations to one mobile station in order to realize soft handoff between base stations (a mobile station moves to a base station without interruption), each base station It is necessary to synchronize the transmission signal generation timing in. Therefore, by establishing synchronization using GPS, N-C
It is possible to establish synchronization of time and transmission signal generation timing of each base station in the DMA communication system.

In the wireless communication station system shown in FIG.
Each of the base stations 81 to 84 is equipped with a GPS receiver. Each base station receives a GPS signal from a GPS satellite 19 to generate a GPS clock signal and a GPS time signal, and synchronizes with these signals within the station. By operating the circuit of, it is possible to establish time synchronization between the base stations. By such control operation, the base stations 81 to 84
In wireless communication with a mobile station (not shown) and a central station 80 which is a relay station for wireless communication, it is possible to establish synchronization of time and generation timing of a transmission signal.

In addition, Japanese Patent Laid-Open No. 2 (1999) published on January 21, 2000
No. 000-23245 “Time synchronization method in CDMA system” (applicant: Fujitsu Limited, inventor: Mitsuru Seta) provides high accuracy only to a base station control device connected to each base station device by a wired transmission line. GPS receiver installed, G
A GPS clock signal and a GPS time signal are generated from the GPS signal received by the PS receiver, the reference clock of the base station control device and the reference time are synchronized, and the transmission delay time via the wired transmission path with each base station device In view of the above, a method for establishing synchronization between base stations is described.

[0010]

However, the above-mentioned conventional radio communication station system has various problems.
In a wireless communication station system that establishes base station synchronization by using a conventional wired transmission line, it is necessary to install a wired transmission line between the central station and each base station, resulting in high equipment costs. There is.

Further, in a wireless communication station system in which a GPS receiver is installed in each base station to establish synchronization of the base stations, the GP
There is a problem in that the installation cost is the same as the number of S receivers, and if a spare GPS receiver is installed as a countermeasure against a failure, the cost further increases.

On the other hand, as a network topology of a wireless communication system, a mesh type is widely known in addition to a star type and a ring type. This is a form of a network configured by combining other network topologies and is used in a large-scale network such as a public network and the Internet. Actual wireless communication systems often have a mesh type configuration. The mesh type configuration in the present invention means a point-to-point (PP) type one-to-one.
Since multiple wireless links are combined and one wireless station has links with multiple wireless stations, not only synchronization for each wireless link is necessary in order to configure a mesh type wireless station communication system. , It is desirable to establish time synchronization for all configured wireless stations.

In a wireless communication system in which wireless stations are arranged in a mesh type, it is not possible to provide one device with a function for synchronizing wireless stations, as in the base station control device in the above-mentioned prior art. However, due to the mesh type configuration, it may be necessary to perform synchronization control via a wireless station (relay station) in the middle, and at this time, relay error accumulates due to the number of relays, so highly accurate time synchronization is required. There is a problem that it cannot be established.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a mesh type wireless station communication system capable of easily establishing time synchronization between wireless stations.

[0015]

SUMMARY OF THE INVENTION The present invention for solving the above-mentioned problems of the prior art includes a time synchronization reference radio station having a GPS receiver, and a plurality of radio stations. In a mesh type wireless station communication system connected via a wireless transmission path to a time synchronization reference wireless station or a wireless station connected to the time synchronization reference wireless station via a wireless transmission path, the time synchronization reference wireless station is a GPS G received from satellite
A GPS time signal and a GPS clock signal are generated based on the PS signal, a GPS time signal and a time signal and a clock signal respectively synchronized with the GPS clock signal are generated, and reference time information is generated based on the time signal and the clock signal. , The wireless station that transmits to the wireless station connected to the time synchronization reference wireless station and that connects to the time synchronization reference wireless station calculates the wireless propagation time from the difference between the time information at which the reference time information was received and the reference time information. , The radio propagation time is transmitted to the time synchronization reference radio station together with transmission time information in the radio station,
The time synchronization reference wireless station calculates the error time by subtracting the sum of the wireless propagation time and the transmission time information from the reference time information, and transmits it to the wireless station as time error information, and the wireless station is based on the time error information. It is characterized by correcting the time information and establishing synchronization with the reference time information.
Time synchronization between wireless stations can be easily established.

Further, in the mesh type wireless station communication system of the present invention, the wireless station which is connected to the time synchronization reference wireless station and establishes the synchronization with the reference time information establishes the time synchronization through the wireless transmission path. The time information that is synchronized with the reference time information is transmitted to the wireless station with which synchronization has not been established, and the wireless station with which synchronization has not been established has the time information that received the synchronized time information,
The wireless propagation time is calculated from the difference with the synchronized time information, and the wireless propagation time is transmitted to the wireless station with the time synchronization establishment together with the transmission time information at the wireless station, and the wireless station with the time synchronization establishment uses the reference time information. , The error time is calculated by subtracting the sum of the radio propagation time and the transmission time information, and the error time is transmitted as time error information to the wireless station that has not established synchronization, and the wireless station that has not established synchronization uses the time information based on the time error information. Is corrected and the synchronization is established for the synchronized time information, and the time synchronization between the wireless stations can be easily established.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings. The function realizing means described below may be any circuit or device as long as it can realize the function, and part or all of the function can be realized by software. is there. Further, the function realizing means may be realized by a plurality of circuits, or the plurality of function realizing means may be realized by a single circuit.

A mesh type radio station communication system according to an embodiment of the present invention has a GPS receiver, and is provided with one time synchronization time synchronization reference radio station which is synchronized with UTC time. The station wirelessly communicates with the wireless stations connected by the wireless transmission path, calculates the time difference from the reference time information based on the wireless propagation time, and corrects the time of the wireless station based on the time error. This is to establish synchronization, which makes it possible to easily establish time synchronization between wireless stations.

Further, the wireless station with which the time synchronization has been established performs the synchronization establishment process with respect to the wireless station connected with the wireless transmission line and having no synchronization, by using the time information of the wireless station with which the time synchronization has been established. As a result, time synchronization between wireless stations can be easily established.

Further, the wireless station which has established the synchronization in the synchronization establishing process uses the time information of the wireless station which has established the time synchronization for the wireless station which is connected to the wireless transmission line and which has not yet established the synchronization. By doing so, time synchronization between wireless stations can be easily established.

The configuration of the mesh type wireless station communication system according to the embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an overall configuration diagram of a mesh type wireless station communication system according to an embodiment of the present invention. As shown in FIG. 1, a mesh type wireless station communication system (hereinafter, a mesh type wireless station communication system of the present invention) according to an embodiment of the present invention includes a time synchronization reference wireless station 10 and wireless stations A11 to A14.
And wireless stations B15 to B18. The mesh type wireless station communication system of the present invention is a time synchronization reference wireless station 10.
Are wireless stations A11 to 14, and wireless station A11 is a wireless station B15.
, 16 and wireless station A12 are wireless stations B15 and 17,
The wireless station A13 has wireless stations B16 and 18, and the wireless station A14.
Are connected to wireless stations B17 and B18 via wireless transmission paths, respectively, and have a mesh type network configuration. In FIG. 1, a wireless transmission path is indicated by a dashed arrow.

The time synchronization reference radio station 10 is a GPS satellite 1
9 has a built-in GPS receiver for receiving the GPS signal transmitted from the GPS receiver, generates a GPS clock signal and a GPS time signal based on the GPS signal received by the GPS receiver, and further synchronizes with the reference time information. Is generated and transmitted to the wireless stations A11 to A14. In addition, wireless stations A11 to 14
When the temporary propagation time information and the time information at the time of transmission of the information in the wireless station A are received from the time synchronization reference wireless station 1
0 calculates the time error information of the source wireless station A based on these information and the time information at the time of receiving the information, and transmits it to the source wireless station A.

Upon receiving the reference time information from the time-synchronization reference wireless station 10, the wireless stations A11 to A14 are based on the received reference time information and the time information at the time of reception of the information at their own stations, and the tentative propagation time. Is calculated and stored, and is transmitted to the time synchronization reference wireless station 10 as temporary propagation time information together with the time information at the time of transmission at the own station. When the time error information is received from the time synchronization reference wireless station 10, the wireless station A11
14 to 14 correct the time information of their own station based on the received time error information and establish synchronization with the reference time information.

Radio stations A11 to A1 synchronized with the reference time information
4 is connected via a wireless transmission path and transmits time information synchronized with the reference time information to the wireless stations B15 to B18 that are not synchronized with the reference time information. Also, radio station B
Upon receiving the wireless propagation time information and the transmission time information of the wireless station B from 15 to 18, the wireless stations A11 to 14 obtain the time error information of the wireless station B of the transmission source based on these information and the time information of the own station. It is calculated and transmitted to the wireless station B of the transmission source.

When the wireless stations B15 to B18 receive the time information synchronized with the reference time information from the connected wireless stations A11 to A14, they are tentative on the basis of the received time information and the reception time information at the own station. Calculate and store the propagation time,
As the temporary propagation time information, it is transmitted to the originating wireless stations A11 to 14 together with the time information at the time of transmission at the local station. When receiving the time difference information from the connected wireless stations A11 to A14, the wireless stations B15 to 18 correct the time information of the own station based on the received time difference information and synchronize with the reference time information. Establish.

FIG. 2 is a schematic block diagram of the time synchronization reference radio station 10 and the radio station A11.
3A and 3B are block diagrams of detailed configurations of a time synchronization reference wireless station 10 and a wireless station A11, respectively. Time synchronization reference radio station 10
As shown in FIG. 2, the wireless unit 21 and the modem unit 22
And a timing generator 23 and a time controller 24. Furthermore, as shown in FIG. 3, the time control unit 24 includes a GPS receiver 241, a time generation unit 242, an oscillator 243, a reference clock 244, and a time information generation unit 245.
And an input / output unit 246 and a time error processing unit 247.

The radio station A11 also includes a radio unit 31, a modem unit 32, a timing generation unit 33, and a time control unit 34.
It consists of and. Further, as shown in FIG. 4, the time control unit 34 includes an input / output unit 341, a time correction unit 342,
Oscillator 343, reference clock 344, time information generation unit 3
45 and a time error processing unit 346.

In the time synchronization reference radio station 10 of FIG.
The wireless unit 21 controls transmission / reception of wireless signals in wireless communication with the wireless station A11. The wireless signal is transmitted to the wireless unit 21.
It is transmitted / received by the antenna connected with. The wireless unit 21 transmits the wireless signal converted by the modem unit 22 and outputs the wireless signal received by the antenna to the modem unit 22.

The modem section 22 performs mutual conversion between radio signals and digital data. When digital data such as time information is transmitted from the time synchronization reference wireless station 10, it is converted to a wireless signal and output to the wireless unit 21, and when a wireless signal is received, converted to digital data and time controlled. Output to the unit 24.

The timing generator 23 includes a time controller 24.
Various timing signals required by the modem unit 22 are generated based on the reference time and the reference clock signal generated in (1) and output to the modem unit 22.

The time control unit 24 generates reference time information synchronized with the time information and clock information included in the GPS signal received from the GPS satellite 19, and outputs it to the modem unit 22. The timing generation unit 2 also generates a reference time and a reference clock signal that are synchronized with the clock information of the GPS signal.
Output to 3. When the temporary propagation time information and the time information at the time of transmitting the temporary propagation time information in the wireless station A11 are received from the wireless station A11, the time control unit 24 causes the time synchronization reference wireless station 10 of the information and the information. The error time between the time synchronization reference wireless station 10 and the wireless station A11 is calculated based on the time at the time of reception, and is output to the modem unit 22 as time error information together with the time information at the time of transmission at the time synchronization reference wireless station 10.

As shown in FIG. 3, in the time control unit 24, the GPS receiver 241 sends the GPS time signal to the GPS time generation unit 242 based on the time information and the clock information included in the GPS signal received from the GPS satellite 19. , And outputs a GPS clock signal to the oscillator 243.

The time generation unit 242 has a GPS receiver 241.
A reference time signal is generated on the basis of the GPS time signal output from and is output to the reference clock 244.

The oscillator 243 generates a reference clock signal synchronized with the GPS clock signal output from the GPS receiver 241, and outputs it to the timing generation section 23 via the reference clock 244 and the input / output section 246.

The reference clock 244 is based on the reference time signal output from the time generation section 242 and the reference clock signal output from the oscillator 243, and the time synchronization reference radio station 10 is connected.
The time in is corrected and the reference time is generated. The reference time generated by the reference clock 244 can be referred to by each device in the time control unit 24. Further, the reference time is output to the timing generation unit 23 via the input / output unit 246.

The time information generating section 245 uses the reference clock 244.
The reference time information is generated on the basis of the reference time generated in the step (3) and output to the input / output unit 246.

The input / output unit 246 is a time information generating unit 245.
The reference time information output in step 3 is output to the modem unit 22.
Further, the input / output unit 246 outputs from the modem unit 22,
Temporary propagation time information from wireless station A11 and wireless station A11
The time information at the time of transmitting the temporary propagation time information in is output to the time error processing unit 247, and the time error information calculated and output by the time error processing unit 247 is output to the modem unit 22. Further, the input / output unit 246 outputs the reference time and the reference clock signal to the timing generation unit 23. In order to perform the control described above, the input / output unit 246 has a function of determining a data output destination based on the type of data. Further, according to the type of data, the input / output unit 246 stores the time at which the data was input, and outputs the time information at the time of transmission or reception together with the data to the modem unit 22 or the time error processing unit 247. To do.

The time error processing section 247 has an input / output section 246.
Provisional propagation time information from the wireless station A11 output from
The wireless station A11 is based on the time when the temporary propagation time information is transmitted and the time when the wireless station A11 receives the information.
The error time in 11 is calculated and output to the input / output unit 246 as time error information.

In the wireless station A11 of FIG. 2, the wireless unit 3
1, the configuration of the modem unit 32 and the timing generation unit 33,
Since it is the same as the corresponding device of the time synchronization reference wireless station 10, description thereof will be omitted.

The time control unit 34 includes the time synchronization reference radio station 1
Based on the reference time information received from 0, the temporary propagation time in wireless communication is calculated and stored, and is output to the modem unit 32 as temporary propagation time information together with the time information at the time of transmission in the wireless station A11. When the time error information is received from the time synchronization reference wireless station 10, the time control unit 34 corrects the time at the wireless station A11 based on the time error information,
Time information based on the corrected time is generated. Further, the time control unit 34 corrects the time and clock signal based on the time error information and outputs the corrected time and clock signal to the timing generation unit 33.

In addition to the functions described above, the time control unit 34
In the time synchronization process with the wireless station B15 or 16 performed after the synchronization with the reference time information is established, the time information in the wireless station A11 is used instead of the reference time information, and the time control unit 24 in the time synchronization reference wireless station 10 is used. Perform the same control. Therefore, in the time synchronization processing with the wireless station B15 or 16, the wireless station A11 plays the same role as the time synchronization reference wireless station 10. In the time control unit 34, the control performed in the time synchronization processing with the time synchronization reference wireless station 10 and the time synchronization processing with the wireless station B15 or 16 are different. Therefore, the wireless station A11 monitors whether or not the synchronization with the reference time information is established, and when the synchronization is established, a control switching means (not shown) for switching control to the time control unit 34 is provided. There is. This control switching means is used as the input / output unit 341.
It may be provided inside.

As shown in FIG. 4, in the time control unit 34, the input / output unit 341 outputs from the modem unit 32,
The reference time information from the time synchronization reference wireless station 10 is output to the time error processing unit 346. Further, the time error processing unit 346
The temporary propagation time information calculated and output in
Further, the input / output unit 341 outputs the time and clock signal to the timing generation unit 33.

In the time synchronization processing with the radio station B15 or 16, the input / output unit 341 performs the same control as the input / output unit 246 of the time synchronization reference radio station 10. Also, the input / output unit 341
Like the input / output unit 246, has a function of determining the output destination of data based on the type of data, and when data is input, the time information at the time of data input is stored and transmitted. The time or the time information at the time of reception is output to the modem unit 32 or the time error processing unit 346 together with the data.

The time correction unit 342 generates time correction information based on the time error information output from the input / output unit 341 and outputs it to the oscillator 343 and the reference clock 344.

The oscillator 343 is continuously operated by the reference clock 344.
To the reference clock 344 and each device in the wireless station A11. When the time correction information is output from the time correction unit 342, the clock signal is corrected,
The corrected clock signal is output.

The reference clock 344 generates time based on the clock signal output from the oscillator 343. The reference clock 344 corrects the time in the wireless station A11 based on the time correction information output from the time correction unit 342 and the clock signal output from the oscillator 343 to generate the time.

The time information generating section 345 uses the reference clock 344.
Time information is generated on the basis of the time generated in step S1, and output to the input / output unit 341. The time information generation unit 345 continuously outputs the time information to the input / output unit 341 at regular intervals.

The time error processing unit 346 includes an input / output unit 341.
Tentative propagation time is calculated based on the reference time information from the time-synchronization reference wireless station 10, the time information when the information is transmitted, and the time information when the information is received,
It is output to the input / output unit 341 as provisional propagation time information. In the time synchronization processing with the wireless station B15 or 16, the time error processing unit 346 performs the same control as the time error processing unit 247 of the time synchronization reference wireless station 10, that is, the wireless station B15 or 16
And the time error information is calculated and output.

In the mesh type wireless communication station system of the present invention, the other wireless stations A12-14 and wireless stations B15-18 in FIG. 1 are also the wireless station A11 shown in FIG. 2 and FIG.
Since the configuration is the same as that of 1, the description of the configuration of these wireless stations will be omitted.

Next, the time synchronization reference radio station 10 and the radio station A11 in the mesh type radio station communication system of the present invention.
The operation of the time synchronization processing with and will be described with reference to FIGS. First, the time synchronization reference radio station 10 uses the GPS satellite 19 in the GPS receiver 241 of the time control unit 24.
The GPS signal transmitted from is received. GPS receiver 2
41 based on the time information and the clock information included in the received GPS signal, the GPS time generation unit 242 receives the GP information.
The S time signal and the GPS clock signal are output to the oscillator 243.

The time generator 242 generates a reference time signal based on the GPS time signal and outputs it to the reference clock 244. Further, the oscillator 243 generates a reference clock signal synchronized with the GPS clock signal and outputs it to the reference clock 244 and each device in the time synchronization reference radio station 10.

The reference clock 244 generates the reference time based on the reference time signal and the reference clock signal output from the time generation unit 242 and the oscillator 243, respectively. Specifically, the reference clock 244 synchronizes with the reference clock signal and corrects the time based on the reference time signal, thereby
A reference time synchronized with C with high accuracy is generated.

The time information generation unit 245 generates reference time information based on the reference time generated by the reference clock 244 when performing the time synchronization processing with other wireless stations, and outputs it to the input / output unit 246. . The input / output unit 246 outputs the reference time information to the modem unit 22. The reference time information output to the modem unit 22 is converted into a radio signal and transmitted to the radio station A11 via the radio unit 21. Also, the input / output unit 246
Is a timing generation unit 2 that determines the reference clock signal generated by the oscillator 243 and the reference time generated by the reference clock 244.
Output to 3. The timing generation unit 23 outputs various timing signals to the modem unit 22 based on the reference clock signal and the reference time. As a result, the modem unit 22
Data transmission / reception operations are performed based on the reference time and the reference clock signal.

The reference time information transmitted from the time synchronization reference wireless station 10 to the wireless station A11 via the wireless transmission path is received by the wireless unit 31 in the wireless station A11 and is then received by the modem unit 32.
After being converted into digital data by, it is output to the input / output unit 341 of the time control unit 34. The input / output unit 341 monitors the time when the reference time information is input, and outputs this time as the reception time together with the reference time information to the time error processing unit 346.

The data operation processing method associated with the synchronization establishment processing will be described below with reference to FIG. FIG. 6 is a flow chart of data calculation of synchronization establishment processing in the mesh type wireless station communication system of the present invention. First, the reference time information T1 from the time synchronization reference wireless station 10 is transferred to the wireless station A1.
1 is transmitted (S11), and the wireless station A11 receives this and outputs it to the time error processing unit 346 together with the received time t1 (S21). The time error processing unit 346 calculates the wireless propagation time between wireless stations based on the reference time information T1 and the received time t1 (S22). The radio propagation time Δ is obtained by Δ = t1−T1 (1). It is assumed that the wireless station A11 has an error in time, and the value obtained by the equation (1) is temporarily stored in the time error processing unit 346 as a temporary propagation time (S2).
3).

Next, the wireless station A11 transmits Δ to the time synchronization reference wireless station 10 as temporary propagation time information with the temporary propagation time (S24). Specifically, the time error processing unit 346
Outputs the temporary propagation time Δ to the input / output unit 341. The input / output unit 341 recognizes that the tentative propagation time Δ has been input, monitors the time at which the tentative propagation time Δ is input, and sets this time as the transmission time t2. It is output to the modem unit 32 together with the time Δ. The modem unit 32 converts these data into wireless communication data, and transmits the data as temporary propagation time information and transmission time information to the time synchronization reference wireless station 10 via the wireless unit 31.

The tentative propagation time information and the transmission time information are received by the radio section 21 of the time synchronization reference radio station 10 (S12), converted into digital data by the modem section 22, and then input / output of the time control section 24. It is output to the unit 246.
The input / output unit 341 monitors the time when the reference time information is input, and sets this time as the reception time T2.
The information is output to the time error processing unit 247 together with the received information.

The time error processing section 247 first compares T2 with Δ + t2 based on the input information. As a result of the comparison, if T2 = Δ + t2 is established, the time synchronization is established, and thereafter the synchronization establishment process ends. If not,
The time error processing unit 247 calculates the time error (S1
3). The time error is calculated by time error = | Δ + t2-T2 | / 2 (2). According to the equation (2), the time synchronization reference radio station 1
The true time error between 0 and the wireless station A11 is calculated.

Next, the time synchronization reference radio station 10 transmits the time error calculated in S13 to the radio station A11 as time error information (S14). Specifically, the time error processing unit 24
7 outputs the time error to the input / output unit 246, and the input / output unit 24
6 is output to the modem unit 22. The modem unit 22 converts the time difference into wireless communication data and transmits it as time difference information to the wireless station A11 via the wireless unit 21.

Upon receiving the time error information (S25), the wireless station A11 outputs it to the time correction unit 342 via the input / output unit 341 of the time control unit 34. Time correction unit 342
Generates time correction information based on the input time error information and corrects the reference time (S26). The time correction unit 342 outputs the generated time correction information to the oscillator 343 and the reference clock 344. The clock signal and the time of the oscillator 343 and the reference clock 344 are respectively corrected based on the time correction information. As a result, the time synchronization between the time synchronization reference wireless station 10 and the wireless station A11 is established.

When the time synchronization with the time synchronization reference radio station 10 is established, the radio station A11 switches the control of the time control unit 34 by the control switching means and is connected by the radio transmission line.
A process for establishing synchronization with the wireless station B15 or 16 for which synchronization has not been established is performed. Specifically, the radio station A11 receives the time information from the radio station A11 by performing the same processing operation as that of the time synchronization reference radio station 10 described above using the time information of its own station instead of the reference time information. Radio station B15 or 16
Performs the same process as the above-described wireless station A11, thereby performing the process of establishing synchronization with the wireless station B15 or 16.

In the mesh type wireless station communication system of the present invention, the process of establishing synchronization with the wireless stations A12 to A14 is performed in the same manner as in the case of the wireless station A11. In addition, wireless station B15-
When the wireless station having the same configuration as the wireless station A11 is connected to the wireless station A11, the above-described synchronization establishing process is performed by the wireless stations B15 to B18 to which the synchronization has been established.

The mesh type wireless station communication system of the present invention has a GPS receiver and is provided with one time synchronization reference wireless station which is synchronized with UTC time, and the time synchronization reference wireless station is connected by a wireless transmission line. The wireless station that transmits the reference time information to the wireless station and receives the reference time information transmits the propagation time information and the transmission time information, and the time synchronization reference wireless station that receives the propagation time information and the transmission time information Information and the time at the time of reception of the information, the time error is calculated and transmitted to the wireless station, and the wireless station corrects the time and the clock signal based on the received time error information. This has the effect of easily establishing highly accurate time synchronization. In particular, in the mesh type wireless station communication system of the present invention, synchronization establishment processing is performed using a wireless transmission path, and it is not necessary to install a GPS receiver in each wireless station, so that the cost of equipment can be reduced as compared with the related art. You can

Further, the wireless station with the time synchronization established establishes the time synchronization with the wireless station connected with the wireless transmission line and the synchronization not established, based on the time information of the wireless station with the time synchronization established. By performing the processing, it is possible to easily establish highly accurate time synchronization between the wireless stations even in the mesh type wireless communication system. That is, the time synchronization reference radio station does not establish synchronization with all radio stations, but the radio station with established synchronization is synchronized with the radio station connected via the radio transmission path and with unestablished synchronization. Since the establishment process is performed, accumulation of relay error due to the number of relays does not occur, and highly accurate time synchronization can be established in any wireless station on the network.

In the mesh type wireless station communication system according to the present invention, the wireless station connected to the wireless transmission line is connected to the wireless station which has not established the time synchronization to establish the synchronization of the time information. By repeating the test mode of continuously transmitting data, the time synchronization can be established more reliably. FIG. 5 is a time chart diagram in the test mode in the mesh type wireless station communication system of the present invention. In FIG. 5, first, the time synchronization reference radio station 1
0 is in the test mode in which the reference time information is transmitted to the wireless station A11 for a certain period. In FIG. 5, reference time information in which one Tx is continuous is shown. Further, in FIG. 5, the test mode is performed three times at intervals. After finishing all the test modes, the wireless station A11 transmits the provisional propagation time Δ and the time t2 at the time of transmission to the time synchronization reference wireless station 10 in synchronization with the timing of the test mode. By repeating the test mode in this way, it is possible to instantly respond to changes in time error. Also,
When confirming synchronization, add time information to the transmission data instead of test mode, without interrupting normal communication,
It is desirable to be able to maintain time synchronization.

Even after the synchronization with each radio station is established, there is a possibility that a clock error may occur because no GPS receiver is installed except for the time synchronization reference radio station 10. In order to deal with such a situation, time information is periodically added to transmission data during normal wireless communication, time synchronization is determined by the above process, and time correction is performed if a time error occurs. Therefore, it becomes possible to maintain highly accurate time synchronization.

The mesh type wireless station communication system of the present invention is effective in establishing new time synchronization or resynchronization, such as when a new wireless station is started up or when the wireless station is restarted during operation. Also, in a mesh type wireless station communication system in which a wireless station having the same configuration as the wireless station A11 is used and connected in multiple stages via a wireless transmission path, the present invention provides the above effects to all wireless stations. It is compatible.
The mesh type wireless station communication system of the present invention can be implemented regardless of the type of wireless communication means.

[0068]

According to the present invention, a time synchronization reference radio station having a GPS receiver and a plurality of radio stations are provided, and the plurality of radio stations are the time synchronization reference radio station or the time synchronization reference radio station. In a mesh type wireless station communication system connected via a wireless transmission path to a wireless station connected via a wireless transmission path, a time synchronization reference wireless station uses a GPS time signal and a GPS time signal based on a GPS signal received from a GPS satellite. Generates a GPS clock signal, generates a GPS time signal, a time signal and a clock signal respectively synchronized with the GPS clock signal, generates reference time information based on the time signal and the clock signal, and connects to the time synchronization reference radio station. The wireless station that transmits to the wireless station and connects to the time synchronization reference wireless station calculates the wireless propagation time from the difference between the time information when the reference time information was received and the reference time information. , The radio propagation time is transmitted to the time synchronization reference radio station together with the transmission time information in the radio station, and the time synchronization reference radio station subtracts the sum of the radio propagation time and the transmission time information from the reference time information to obtain an error. The time is calculated and transmitted as time error information to the wireless station, and the wireless station corrects the time information based on the time error information and establishes synchronization with the reference time information, so that the time synchronization between the wireless stations is achieved. There is an effect that can be easily established.

Further, according to the present invention, the wireless station that is connected to the time synchronization reference wireless station and has established the synchronization with the reference time information has the synchronization unestablished to connect via the wireless transmission path. The wireless station transmits the time information synchronized with the reference time information to the wireless station, and the wireless station with unestablished synchronization calculates the wireless propagation time from the difference between the time information when the synchronized time information is received and the synchronized time information, The wireless propagation time is transmitted to the wireless station with the time synchronization establishment together with the transmission time information in the wireless station,
The radio station with time synchronization establishment calculates the error time by subtracting the sum of the radio propagation time and the transmission time information from the reference time information, and transmits the time error information to the radio station with unestablished synchronization,
A wireless station that has not established synchronization has the effect of easily establishing time synchronization between wireless stations by correcting the time information based on the time error information and establishing synchronization with the synchronized time information.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a mesh type wireless station communication system according to an embodiment of the present invention.

FIG. 2 is a schematic block diagram of a time synchronization reference wireless station 10 and a wireless station A11.

FIG. 3 is a detailed configuration block diagram of a time synchronization reference wireless station 10.

FIG. 4 is a detailed configuration block diagram of a wireless station A11.

FIG. 5 is a time chart diagram in the test mode in the mesh radio station communication system according to the embodiment of the present invention.

FIG. 6 is a flowchart diagram of data calculation of synchronization establishment processing in the mesh type wireless station communication system according to the embodiment of the present invention.

FIG. 7 is a diagram showing a radio paging method synchronization method in a conventional radio station communication system.

FIG. 8 is an N-CD in a conventional radio station communication system.
It is the figure which showed the synchronization method in the mobile telephone system in MA communication system.

[Explanation of symbols]

10 ... Time synchronization reference radio station, 11, 12, 13, 14
... Wireless station A, 15, 16, 17, 18 ... Wireless station B, 1
9 ... GPS satellite, 21, 31 ... Radio unit, 22, 32
... Modem section, 23,33 ... Timing generation section, 2
4, 34 ... Time control unit, 70, 80 ... Central office, 7
1, 72, 73, 74, 81, 82, 83, 84 ... Base station, 75, 76, 77 ... Mobile station, 241 ... GPS receiver, 242 ... Time generation unit, 243, 343 ... Oscillator, 244, 344 ... Reference clock, 245, 345 ... Time information generating unit, 246, 341 ... Input / output unit, 24
7, 346 ... Time error processing unit, 342 ... Time correction unit

Continued front page    F term (reference) 2F002 AA05 BB00 BB04 DA00 FA16                       GA06                 5J062 AA08 AA13 CC07                 5K047 AA18 BB01 GG02 GG11 GG56                 5K067 AA41 DD25 DD57 EE10 GG01                       GG11 HH21

Claims (2)

[Claims] 1. A time synchronization reference radio station having a GPS receiver, and a plurality of radio stations, wherein the plurality of radio stations provide a radio transmission path to the time synchronization reference radio station or the time synchronization reference radio station. In a mesh type wireless station communication system connected to a wireless station connected via a wireless transmission path, the time synchronization reference wireless station receives G from a GPS satellite.
A GPS time signal and a GPS clock signal are generated based on the PS signal, a GPS time signal and a time signal and a clock signal respectively synchronized with the GPS clock signal are generated, and reference time information is generated based on the time signal and the clock signal. And transmits it to a radio station connected to the time synchronization reference radio station, and the radio station connected to the time synchronization reference radio station, the difference between the time information at which the reference time information is received and the reference time information. Wireless propagation time is calculated from, the wireless propagation time is transmitted to the time synchronization reference wireless station together with transmission time information in the wireless station, the time synchronization reference wireless station, from the reference time information, the wireless propagation time and An error time is calculated by subtracting the sum with the transmission time information, and the error time is transmitted to the wireless station as time error information. Wireless Mesh station communication system, characterized in that correcting the time information, to establish synchronization with respect to the reference time information based. 2. A wireless station that is connected to a time synchronization reference wireless station and has established synchronization with the reference time information is a wireless station that has not established synchronization and is connected to the wireless station through the wireless transmission path. Transmitting time information synchronized with the time information, the wireless station that has not yet established synchronization calculates the wireless propagation time from the difference between the time information that received the synchronized time information and the synchronized time information, and Transmitting the propagation time together with the transmission time information in the wireless station to the wireless station of the time synchronization establishment, the wireless station of the time synchronization establishment, from the reference time information,
An error time is calculated by subtracting the sum of the radio propagation time and the transmission time information, and the time error information is transmitted to the radio station with no synchronization established. The mesh type wireless station communication system according to claim 1, wherein time information is corrected based on the time information and synchronization is established with respect to the synchronized time information.