JPH11112410A - Synchronization evaluating system for base station of mobile object communication network - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely execute synchronization evaluation based on absolute time with respect to the base station of a mobile object communication network by detecting the timing signal of absolute time provided for the radio wave of an artificial satellite and measuring the step-out of synchronization from absolute time. SOLUTION: A reference time and frequency generator 10 receives the radio wave (GPS radio wave) of an artificial satellite and generates absolute time data Tref, a timing signal UTC1pps generated each second by synchronizing with this absolute time information and a clock fclk synchronizing with it. A mobile station receiving part 20 receives the radio wave of the control channel frequency of the base station of the mobile object communication network STi, detects the slot of a communication frame and generate-outputs a timing signal Tfi. A time interval measuring device 30 receives the timing signal UTC1 pps to start the counting of the clock fclk, receives the timing signal Tfi to stop counting and supplies time difference data Tdi to a signal processing means 40, which calculates an absolute synchronization step-out quantity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a radio wave transmitted by a mobile communication network base station, which stores an absolute time at which frame timing to be transmitted is synchronized or a difference between base stations at an arbitrary place (field). The present invention relates to a mobile communication network base station synchronization evaluation system which can be easily measured and evaluated.

[0002]

2. Description of the Related Art PHS (Personal Han) is a mobile communication.
In the dy phone system, the base station synchronizes frames to improve the frequency use efficiency of a small number of channels, so that frame synchronization control is performed between adjacent base stations. However, in an area where radio waves from a plurality of base stations and different carriers overlap, there is no synchronization standard, which may cause unnecessary confusion. Therefore, an accurate evaluation apparatus for frame synchronization is required.

FIG. 4 shows a TDMA used in a mobile communication network.
1 is an example of a communication frame configuration. PHS is TDM that divides 5 milliseconds of one frame into 8 slots and transmits them in a time-division manner.
A (Time Division Multiple Access) communication method. In this frame, four slots are used for downlink communication and four slots are used for uplink communication. The carriers include a control carrier and a communication carrier. By the way, the control carrier carrying various identification codes uses the same frequency for both downlink and uplink. As shown in the frame mapping of FIG. 4A, the control information is repeated with a cycle of 100 milliseconds of 20 frames. Sent. The control information transmitted and output by the base station uses four downlink slots out of eight slots per frame. Each downlink slot is assigned a different slot position that does not cause a collision between adjacent base stations STi (i = 1 to n), and each base station sequentially transmits and outputs control information to the corresponding slot in a time-division manner. By receiving and demodulating the control information of this slot, the identification code of each base station STi can be obtained. Note that the identification code includes a PS call code, a system call code, and a carrier identification code for wireless monitoring, and a base station ID for identifying a base station and a communication carrier can be identified from these.

Conventionally, as means for evaluating the synchronization of a mobile communication base station, a relative synchronization relationship between a plurality of base stations has been evaluated. That is, as shown in, for example, FIG. 4B, the base station IDs of the corresponding base stations ST1 and ST2 are obtained from the control information of the control carrier of at least two base stations in the field.
When the information is received, the slot of the corresponding frame is detected, and at the timing when the matching of the corresponding base station ID is detected, ST1,
It generates and outputs timing signals Tf1 and Tf2 of ST2. In response to the calculation, the time difference in this section is measured by a counter, and the time difference data TD2 is divided by 5/8 milliseconds, which is the slot unit time, to obtain the remaining time value (5).
/ 8 milliseconds) is obtained as a relative synchronization shift amount. According to the above-described measurement method, a method of determining whether the relative synchronization relationship between the two base stations is within a normal range has been adopted.
The normal range of the amount of synchronization deviation is, for example, ± 10
The standard is within microseconds.

[0005]

As described above, in the conventional method, since the amount of synchronization deviation obtained is a relative deviation, it is difficult to identify which base station is causing the synchronization deviation. is there. As a matter of course, a synchronization shift due to reception by a single base station cannot be detected from the above measurement principle. In addition, since there is no reference time between base stations of different mobile communication network operators, pass / fail cannot be determined, and the same frequency band may be shared. As described above, in the conventional method, it was impossible to evaluate the frame synchronization shift state of the base station based on the absolute time. Accordingly, the problem to be solved by the present invention is to use an absolute time, measure and realize a synchronization deviation from the absolute time, and perform accurate synchronization evaluation based on the absolute time for one or more mobile communication network base stations. It is an object of the present invention to provide a mobile communication network base station synchronization evaluation system that can perform the above.

[0006]

First, a means for solving the above-mentioned problem is to receive a radio wave of a control channel transmitted by a base station of a mobile communication network and to adjust a slot timing of a communication frame of the base station. Detects and receives GPS radio waves from an artificial satellite with a built-in atomic frequency standard, detects a timing signal generated every second of the absolute time of the GPS signal, measures the time difference between the two timing signals, and determines the absolute value of the base station. This is a means for detecting the amount of synchronization deviation. As a result, a synchronization evaluation system for a mobile communication network base station can be realized. According to the above invention, the absolute time is used, the synchronization deviation from the absolute time is measured and realized, and accurate synchronization evaluation based on the absolute time for the mobile communication network base station can be performed.

FIG. 1 and FIG. 2 show a solution according to the present invention. Second, in order to solve the above-mentioned problem, in the configuration of the present invention, a radio wave of a control channel transmitted by a single base station of a mobile communication network is received and a slot timing signal Tf of a communication frame of the single base station is received. And base station I
A mobile station receiving unit 20 for demodulating and outputting D, a highly stable timing signal UTC 1 pps generated every second synchronized with the absolute time, and a reference time / frequency generator 10 for generating time data; Reference time / frequency generator 1
Timing signal UTC 1pps generated every second from 0
And a time interval measuring unit 30 for measuring time difference data TD between the slot timing signal Tf of the communication frame from the mobile station receiving unit 20 and the time interval data TD (5/8 ms) There is a configuration unit that includes a unit that detects the remaining value divided by the above as the absolute synchronization deviation amount from the absolute time. According to the above-mentioned invention, accurate synchronization evaluation based on the absolute time for a single mobile communication network base station can be realized by using the absolute time and measuring and realizing the synchronization deviation from the absolute time.

Thirdly, in order to solve the above-mentioned problem, in the configuration of the present invention, a radio wave of a control channel transmitted by a plurality of target base stations STi (i = 1 to n) of a mobile communication network is received. And a mobile station receiving section 20 for sequentially detecting a slot timing signal Tfi (i = 1 to n) of a communication frame of each base station, demodulating and outputting a base station ID, for one second synchronized with the absolute time. Highly stable timing signal UTC1pp generated every time
Reference time / frequency generator 1 for generating s and time data
0, and time intervals for measuring the time difference data TDi between the timing signal UTC 1 pps generated every second from the reference time / frequency generator 10 and the slot timing signal Tfi of the communication frame from the mobile station receiver 20. Means comprising a measuring device 30 for detecting a residual value obtained by dividing the time difference data TDi of each base station by a slot cycle time (5/8 millisecond) of a communication frame as an absolute synchronization deviation amount from an absolute time of each base station. There is a configuration means provided with: According to the above-described invention, accurate synchronization evaluation based on the absolute time for a plurality of mobile communication network base stations can be realized by using the absolute time and measuring and realizing the synchronization deviation from the absolute time.

Further, the means of the storage medium 45 for storing the absolute synchronization deviation of the single or plural base stations STi measured many times over a long time together with the base station IDi and the absolute time data Tref at the time of acquiring the time difference data TDi are moved as described above. There is a configuration provided in a synchronization evaluation system for a mobile communication network base station.

The measured single or plural base stations S
The absolute synchronization deviation amount of Ti is calculated based on the base station IDi and the time difference data T.
Along with the absolute time data Tref at the time of obtaining Di, the network management center 90 via external communication means (for example, the mobile communication means itself, other wireless communication means, wired communication means, etc.).
There is a configuration in which means for transmitting to a mobile communication network base station synchronization evaluation system is provided. In this case, each base station ST
Remote monitoring functions such as abnormalities and trends in timing between i and base stations, trends in reference frequency of each base station STi, and identification of abnormal base stations can be realized. In addition, from the time-dependent change of the amount of synchronization deviation many times, there is an advantage that the change of the reference frequency, which is the oscillation source built in each base station STi, can be individually found.

In the absolute synchronization deviation amount obtained as described above, if the absolute synchronization deviation amount exceeds a predetermined time difference range, this is transmitted to the network management center 90 via external communication means. Is provided in the above-mentioned mobile communication network base station synchronization evaluation system. In this case, the abnormality is notified each time a synchronization deviation abnormality occurs in a plurality of base stations, so that abnormality monitoring of a large number of mobile communication network base stations can be easily realized.

As a reference time / frequency generator 10 for generating a highly stable timing signal UTC 1 pps synchronized with an absolute time in the above-mentioned mobile communication network base station synchronization evaluation system, an artificial satellite incorporating an atomic frequency standard is used. A means for receiving a radio wave from the controller and generating a highly stable timing signal UTC 1 pps synchronized with the absolute time can be applied.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings together with embodiments.

The present invention will be described below with reference to the system block diagram of FIG. 1, the diagram for explaining the amount of synchronization deviation measurement in FIG. 2, the example of the communication frame configuration in FIG. 4, and the block diagram of the reference frequency generator in FIG. explain. In FIG. 1, a plurality of base stations are STi (i = 1 to n). The configuration of FIG. 1 is a configuration example including a reference time / frequency generation device 10, a mobile station receiving unit 20, a time interval measuring device 30, a signal processing unit 40, a storage medium 45, and a display unit 60. is there.

The reference time / frequency generator 10 includes an absolute time data Tref, which is absolute time information, a high-precision timing signal UTC 1pps generated every second in synchronization with the absolute time information, and a clock fclk synchronized therewith. (For example, 10 MHz). This device is disclosed in Japanese Patent Application No. 06-31.
This is described in detail in "Reference Frequency Generator" of Japanese Patent No. 4192, and has a configuration example shown in FIG. Radio waves of artificial satellites with built-in atomic frequency standard using this technology (GPS radio waves)
Receiving the absolute time data Tref
(Year, month, day, hour, minute, second) and a 1-second unit timing signal UTC synchronized with the absolute time.
As a result, the timing signal UTC 1pps generates a timing signal based on the absolute time. Here, as the required accuracy required for the timing signal UTC 1 pps, an accuracy of 1e-7 is required, for example, assuming 100 ns per second. On the other hand, the reference time / frequency generator 10 of the present invention receives GPS radio waves and generates the timing signal UTC 1 pps from the absolute reference time signal, so that the time accuracy is sufficiently more stable than the required accuracy.

The mobile station receiving section 20 receives radio waves of the control channel frequency of a plurality of mobile communication network base stations STi in the same manner as in the prior art, and sequentially receives the base station IDi of the target base station every second. A slot of a communication frame that matches (i = 1 to n) is detected, and a predetermined timing signal Tfi (i = 1 to n) for detecting the base station IDi is generated and output (see FIG. 2A). This operation is performed by sequentially changing the base stations IDi for which coincidence is detected.

As shown in FIG. 2, the time interval measuring device 30 has a timing signal UTC1pp which is an absolute time signal generated every second from the reference time / frequency generating device 10.
s, the counting of time is started by a clock fclk, for example, a 10 MHz clock, and the counting is stopped by receiving the timing signal Tfi of the corresponding base station IDi from the mobile station receiving unit 20, and the counting period (see FIG. 2B) Is supplied to the signal processing means 40 as time difference data TDi. In this measurement operation, measurement is performed sequentially while changing the base station IDi.

The signal processing means 40 receives the time difference data TDi sent every one second as described above and, as shown in FIG. 2C, divides it by 5/8 milliseconds, which is the unit time of the frame slot, to obtain the remaining value. A certain time value (less than ／ millisecond) is obtained as an absolute synchronization shift amount with reference to the absolute time. As a result, there is obtained an advantage that only the timing signal Tfi of a single base station is received and an absolute synchronization deviation amount from an absolute time reference is obtained. Of course, it goes without saying that the relative synchronization deviation between the plurality of base stations STi can be easily obtained as the difference between the absolute synchronization deviations of the base stations STi as in the related art.

The display means 60 displays the specified base station IDi, the absolute time data, the absolute synchronization deviation amount, and the relative synchronization deviation amount on the display device. In addition, you may display in the form of a graph so that the transition of each change with time can be visually recognized. Further, when an abnormal value in which the value of the absolute synchronization deviation amount or the relative synchronization deviation amount exceeds a predetermined time difference range is detected, a display form for notifying and displaying the abnormality value may be provided. In the case where a communication unit with the outside described later is provided, the display unit 60 may be deleted as desired.

If desired, a storage medium 45 such as a semiconductor memory or a magnetic recording device is provided, and the absolute synchronization deviation amount of the plurality of base stations STi measured many times over a long period of time can be used to obtain the base station IDi and the absolute synchronization deviation when the time difference data TDi is obtained. A configuration for temporarily storing the data together with the time data Tref is added. Then, the stored data may be read out a large number of times, and as shown in the transition diagram of FIG. 7, the transition of the amount of synchronization deviation of the evaluation target base station STi over time may be statistically displayed. The change in the statistical display has a new remarkable advantage that the change in the reference frequency, which is the oscillation source built in each base station STi, can be individually found. For example, in the base station ST3 in FIG. 7, ΔT = 10 hours = 36000 seconds, Δ
The frequency deviation of the oscillation source when S = 6 microseconds is Δ
It can be easily calculated as S / ΔT = 1.67e−10. Here, e is an exponential expression. From this frequency deviation value, each base station S
It is possible to evaluate the oscillation source incorporated in Ti.

Further, there is a configuration including communication means and a network management center 90 shown in the system block diagram of FIG. In this case, the network management center 9 together with the absolute synchronization deviation amount data from the signal processing means 40 or the absolute synchronization deviation amount data read from the storage medium 45 and the corresponding base station IDi and absolute time data Tref.
Communicate to 0. This allows the network management center 9
In the case of 0, data received from a plurality of synchronization evaluation systems is analyzed to analyze abnormalities and trends in timing between base stations STi and base stations, deviations and trends in reference frequency of each base station STi, identification of abnormal base stations, and the like. The advantage that remote monitoring becomes possible is obtained.

According to the above-mentioned invention, an artificial satellite having a built-in atomic frequency standard is detected by receiving a radio wave of a control channel transmitted by a base station of a mobile communication network, detecting a slot timing of a communication frame of the base station. By detecting the GPS signal, detecting the timing signal generated every second of the absolute time of the GPS signal, measuring the time difference between the two timing signals, and detecting the absolute synchronization deviation amount of the base station, Since it is possible to detect the absolute synchronization deviation amount from the absolute time of each base station STi, there is obtained an advantage that accurate synchronization evaluation for the mobile communication network base station can be performed. Of course, accurate measurement and evaluation based on absolute time can be performed even for base stations of different communication network operators. In addition, accurate evaluation can be performed in a congested area where several tens of base stations can receive, and it is possible to detect a communication trouble related to a synchronization shift. By these means, it is possible to improve the frequency use efficiency and quality by using radio waves of the same control channel in a time-division manner.

In the above description of the embodiment, the timing signal UTC 1pps is generated in units of one second in the configuration example of FIG. 5, but if necessary, as shown in the configuration example of FIG. Timing signal UTC1pp
Synchronous reset at s, clock fc with down count value generated at 5 ms cycle or 5/8 ms cycle
A frequency dividing means for dividing the lk clock to a predetermined frequency is provided, and the output is supplied to the time interval measuring device 30 as a timing signal UTC1pps.
pps time interval measuring device 30 and signal processing means 40
Alternatively, a configuration may be adopted in which a plurality of base stations can be measured in a short time.

In the description of the above-described embodiment, a PHS communication base station has been described as a specific example. However, the same applies to other communication modes in which the same frame synchronization is desired between a plurality of base stations. It can be applied by a measurement method based on absolute time.

[0025]

According to the present invention, the following effects can be obtained from the above description. According to the configuration of the present invention, the radio wave of the control channel transmitted by the base station of the mobile communication network is received, the slot timing of the communication frame of the base station is detected, and the GPS of the artificial satellite incorporating the atomic frequency standard is detected.
Each radio base station receives a radio wave, detects a timing signal generated every second of the absolute time of the radio wave, measures a time difference between the two timing signals, and detects an absolute synchronization shift amount of the base station. Since the absolute synchronization deviation amount from the absolute time of the station STi can be detected, there is an advantage that accurate synchronization evaluation with respect to the mobile communication network base station can be performed. In addition, since the same absolute time can be obtained in any region or place, the GPS radio wave is convenient and has an advantage that it can be effectively used as a reference device for slot timing of a communication frame. Also, from the chronological transition of the amount of synchronization deviation many times,
An advantage is also obtained in that a change in the reference frequency, which is an oscillation source incorporated in each base station STi, can be found individually.

[Brief description of the drawings]

FIG. 1 is a system block diagram of the present invention.

FIG. 2 is an explanatory diagram of an absolute synchronization shift amount measurement of the present invention.

FIG. 3 is another system block diagram of the present invention.

FIG. 4 is an explanatory diagram of frame mapping and a conventional relative synchronization shift amount measurement.

FIG. 5 is a block diagram of a reference time / frequency generator used in the present invention.

FIG. 6 is a block diagram of another reference time / frequency generator used in the present invention.

FIG. 7 is an example of transition of an absolute synchronization shift amount according to the present invention.

[Explanation of symbols]

 STi base station 10 reference time / frequency generator 20 mobile station receiver 30 time interval measuring device 40 signal processing means 45 storage medium 60 display means 90 network management center

Claims (7)

[Claims] 1. A radio wave transmitted by a base station of a mobile communication network is received, a slot timing of a communication frame of the base station is detected, and a radio wave of an artificial satellite having a built-in atomic frequency standard is received. A synchronization evaluation system for a mobile communication network base station, characterized in that a timing signal of an absolute time of the base station is detected, and a time difference between the two timing signals is measured to obtain an absolute synchronization shift amount of the base station. 2. A mobile station that receives a radio wave transmitted by a single base station of a mobile communication network, detects a slot timing signal of a communication frame of the single base station, and demodulates and outputs the base station ID. A receiver, a reference time / frequency generator for generating a timing signal synchronized with the absolute time, a timing signal from the reference time / frequency generator, a slot timing signal of a communication frame from the mobile station receiver, A time interval measuring device for measuring the time difference data, and means for obtaining a remaining value obtained by dividing the time difference data by the slot cycle time of the communication frame as an absolute synchronization deviation amount from the absolute time. Mobile communication network base station synchronization evaluation system. 3. A radio wave transmitted by a plurality of target base stations of a mobile communication network is received, a slot timing signal of a communication frame of each base station is sequentially detected, and the base station ID is demodulated and output. A mobile station receiver, a reference time / frequency generator for generating a timing signal synchronized with the absolute time, a timing signal from the reference time / frequency generator, and a slot timing of a communication frame from the mobile station receiver. A time interval measuring device for measuring time difference data with respect to a signal; and means for detecting a remaining value obtained by dividing the time difference data by a slot cycle time of a communication frame as an absolute synchronization deviation amount from an absolute time. A synchronization evaluation system for a mobile communication network base station. And means for storing the absolute synchronization deviation amount of a single or a plurality of base stations measured a number of times together with the base station IDi (i = 1 to n) and the absolute time data at the time of obtaining the time difference data. The mobile communication network base station synchronization evaluation system according to claim 2 or 3. 5. A system for transmitting a measured absolute synchronization deviation of one or more base stations together with the base station IDi and the absolute time data at the time of acquiring the time difference data to a network management center via an external communication means. The system for evaluating synchronization of a mobile communication network base station according to claim 2 or 3. 6. A means for transmitting a notification to the network management center via an external communication means when the absolute synchronization deviation exceeds a predetermined time difference range in the obtained absolute synchronization deviation. The system for evaluating synchronization of a mobile communication network base station according to claim 2 or 3, wherein: 7. A reference time / frequency generator for generating a highly stable timing signal synchronized with an absolute time receives a radio wave from an artificial satellite having a built-in atomic frequency standard, and receives a highly stable signal synchronized with the absolute time. 4. The system for evaluating synchronization of a mobile communication network base station according to claim 2, wherein a timing signal is generated.