JP4646742B2 - Base station apparatus and synchronization timing shift detection method - Google Patents

Description

  The present invention relates to a base station apparatus and a synchronization timing shift detection method.

  Some mobile communication systems use GPS in order to establish synchronization between base station apparatuses (for example, Patent Document 1). In such a mobile communication system, each base station device includes a GPS receiver. The GPS receiver receives a GPS signal (for example, a 1-second pulse signal) transmitted from a GPS satellite. Each base station apparatus establishes synchronization timing with other base station apparatuses by using the received GPS signal as a synchronization signal serving as a reference for establishing synchronization. More specifically, the GPS receiver outputs a GPS signal as a timing signal. Each base station apparatus generates a timing according to a timing signal output from the GPS receiver and uses it as a synchronization timing. By doing so, each base station device can establish the synchronization timing with the GPS satellite, and as a result, the synchronization timing can be established with the other base station devices.

By the way, when a GPS receiver provided in the base station device fails, the GPS receiver detects its own failure and outputs a status signal for notifying the failure. The base station device detects a failure of the GPS receiver based on this status signal, stops using the GPS signal received by the failed GPS receiver as a synchronization signal, and is received by other devices. When a signal that is present can be used as a reference, the other signal is used as a synchronization signal. As signals received by other devices, when two GPS receivers are provided, the GPS signals received by another GPS receiver can be used, and other base stations can be used. A signal received from a station apparatus or an exchange can also be used. If the base station apparatus is provided with a high-accuracy crystal oscillator, a signal oscillated by the crystal oscillator can be used until the GPS receiver is restored.
JP-A-10-145845

  However, the GPS receiver may not be able to detect a slight timing shift of the timing signal output from itself as a failure. In such a case, since the status signal is not output from the GPS receiver, the base station device cannot switch the device that receives the synchronization signal used as a reference for establishing synchronization, and as a result, with other base station devices. Communication will be performed in a state where synchronization timing cannot be established.

  Accordingly, one of the objects of the present invention is to provide a base station apparatus and a synchronization timing shift detection method capable of detecting a timing shift of a timing signal output from a GPS receiver.

  A base station apparatus according to the present invention for solving the above problems is a base station apparatus used in a mobile communication system, and the mobile communication system includes a plurality of communication apparatuses including the base station apparatus. Each of the communication devices receives a synchronization signal serving as a reference for establishing synchronization, establishes a synchronization timing with the other communication devices based on the synchronization signal, and transmits a communication signal at the established synchronization timing. The base station apparatus includes a GPS receiver that receives a GPS signal as the synchronization signal and outputs a timing signal corresponding to the GPS signal. The base station apparatus generates a timing signal output from the GPS receiver. Based on synchronization establishment means for establishing synchronization timing with another communication device, and communication signal reception for receiving a communication signal from at least one of the communication devices. Timing deviation detection for detecting that there is a timing deviation in the timing signal based on the synchronization timing established by the means, the synchronization establishment means, and the timing according to the communication signal received by the communication signal receiving means Means.

  According to this, the base station apparatus is output from the GPS receiver based on the synchronization timing established based on the timing signal output from the GPS receiver and the communication signal transmitted by another communication apparatus. It is possible to detect that there is a timing shift in the timing signal.

  Further, in the base station apparatus, an apparatus for receiving a synchronization signal as a reference for establishing synchronization by the synchronization establishing means when the timing deviation detecting means detects that there is a timing deviation in the timing signal. Further, a synchronization signal receiving device switching means for switching to a device other than the GPS receiver that outputs the timing signal in which the timing deviation is detected may be further included.

  According to this, when it is detected that there is a timing shift in the signal output from the GPS receiver, the base station device can switch the device that receives the synchronization signal as a reference for establishing synchronization. become.

  Further, in each of the above base station apparatuses, the communication signal receiving means receives communication signals from a plurality of the communication apparatuses, and the timing deviation detecting means includes the synchronization timing established by the synchronization establishing means, and the communication signal receiving means It is good also as detecting that there is a timing gap in the timing signal based on the timing according to the communication signal transmitted by each of the plurality of communication devices received by.

  According to this, the base station device is based on the synchronization timing established by establishing synchronization with the signal output from the GPS receiver, and the communication signal transmitted by each of a plurality of other communication devices, It can be detected with higher accuracy that there is a timing shift in the timing signal output from the GPS receiver.

  Further, in each of the above base station apparatuses, another communication apparatus establishment synchronization timing which is a synchronization timing established by the communication apparatus that has transmitted the communication signal based on a timing according to the communication signal received by the communication signal receiving means. The other communication device establishment synchronization timing acquisition means for acquiring, the timing deviation detection means, by comparing the synchronization timing established by the synchronization establishment means and the other communication device establishment synchronization timing, It may be detected that there is a timing shift in the timing signal. Further, in this base station apparatus, the communication signal receiving means receives communication signals from a plurality of the communication apparatuses, and the other communication apparatus establishment synchronization timing acquisition means sets other communication apparatus establishment synchronization timing for each of the communication apparatuses. The timing deviation detection means acquires and determines that the timing signal has a timing deviation when the synchronization timing established by the synchronization establishment means is different from any of the plurality of other communication apparatus establishment synchronization timings. It's good.

  Further, in each of the above base station apparatuses, the timing deviation detecting means predicts the timing at which a signal is received by the communication signal receiving means based on the synchronization timing established by the synchronization establishing means, and the prediction When the communication signal received by the communication signal receiving means is not received at the timing to be received, the synchronization timing established by the communication device that transmitted the communication signal is different from the synchronization timing established by the synchronization establishment means The timing deviation detecting means includes a synchronization timing established by the communication device that has transmitted the signal indicated by the signal received by the communication signal receiving means by the determining means; When it is determined that the synchronization timing established by the synchronization establishment means is different , It is determined that there is a timing offset to said timing signal, it is also possible.

  Further, in each of the above base station devices, the communication signal receiving means may receive a communication signal from at least one of the other base station devices.

  According to this, the base station apparatus detects that there is a timing shift in the signal output from the GPS receiver by receiving a communication signal (for example, a notification signal) transmitted by another base station apparatus. be able to.

  A synchronization timing deviation detection method according to the present invention is a synchronization timing deviation detection method for detecting a synchronization timing deviation in a base station device used in a mobile communication system, and the mobile communication system includes: A plurality of communication devices including the base station device, wherein each of the communication devices receives a synchronization signal as a reference for establishing synchronization, and synchronizes with the other communication devices based on the synchronization signal; A GPS receiver that establishes timing, transmits and receives a communication signal at the established synchronization timing, receives the GPS signal as the synchronization signal, and outputs a timing signal corresponding to the GPS signal A synchronization establishment step for establishing synchronization timing with the other communication device based on a timing signal output from Based on a communication signal receiving step for receiving a communication signal from at least one of the communication devices, a synchronization timing established in the synchronization establishment step, and a timing according to the communication signal received in the communication signal reception step And a timing shift detection step for detecting that there is a timing shift in the timing signal.

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

  FIG. 1 is a system configuration diagram of a mobile communication system 1 according to the present embodiment. As shown in FIG. 1, the mobile communication system 1 includes a base station device 10, an exchange 20, and a mobile station device 30. The mobile communication system 1 includes a plurality of base station devices 10. Each base station apparatus 10 includes one or more GPS receivers 11, and each GPS receiver 11 receives a GPS signal (described later) transmitted from a GPS satellite 40.

  The base station device 10 includes a CPU and a memory, and is a communication device that performs wireless communication with one or a plurality of mobile station devices 30. The base station apparatus 10 has a range in which radio communication with the mobile station apparatus 30 is possible (a geographical range in which radio waves transmitted to each other can reach), and this range is called a cell. The cells of each base station apparatus 10 have overlapping portions, and radio waves transmitted to each other may arrive between the base station apparatuses 10.

  Further, as will be described in detail later, the base station apparatus 10 receives a synchronization signal that is a reference for establishing synchronization, and communicates with other communication apparatuses included in the mobile communication system 1 based on the synchronization signal. Thus, synchronization timing is established, and communication signals are transmitted and received at the established synchronization timing. The base station apparatus 10 uses a GPS signal (described later) received by the GPS receiver 11 as one of synchronization signals.

  The mobile station device 30 includes a CPU and a memory, and is a communication device that communicates with another mobile station device 30 or a communication device (such as a telephone) via the base station device 10 and the exchange 20. is there. When the user designates a communication partner in the mobile station device 30 and makes a call, the mobile station device 30 is connected to the exchange 20 via the base station device 10. The exchange 20 enables exchange of communication signals between the mobile station device 30 and the communication device of the communication partner by performing an exchange process for connecting to the designated communication partner.

  In addition, when a call specifying the mobile station device 30 is made in another communication device, an exchange process for connecting to the mobile station device 30 is performed in the exchange 20. Specifically, the exchange 20 determines which base station device 10 is the base station device 10 that can communicate with the mobile station device 30 and via the base station device 10 that can communicate with the mobile station device 30, Make a general call. In response to this simultaneous call, the mobile station device 30 performs incoming call notification processing such as ringing of the bell, and when the user goes off-hook, transmission / reception of communication signals between the mobile station device 30 and the communication device of the communication partner is started. The

  In order to perform such outgoing / incoming processing, the base station device 10 transmits a notification signal including predetermined notification information to the mobile station device 30. The broadcast signal is one of the communication signals, but is unilaterally transmitted from the base station apparatus 10 to one or a plurality of mobile station apparatuses 30 existing in the cell. The broadcast information specifically includes base station apparatus identification information for identifying the base station apparatus 10, a general call signal for the general call, and the like.

  The exchange 20 includes a CPU and a memory, and is a communication device that enables communication of the mobile station device 30 by performing the above-described exchange processing. Similar to the base station apparatus 10, the exchange 20 receives a synchronization signal serving as a reference for establishing synchronization, and synchronizes with other communication apparatuses included in the mobile communication system 1 based on the synchronization signal. Timing is established and communication signals are transmitted and received at the established synchronization timing. The exchange 20 is supplied with a reference clock signal from a clock generator (not shown) having a standard clock, and uses this reference clock signal as one of synchronization signals.

  The GPS satellite 40 transmits a GPS signal. This GPS signal includes a signal called 1PPS (1 second pulse signal). This 1PPS is a pulse signal every second, and 1 second indicated by 1PPS is considered to be extremely accurate. In the mobile communication system 1, each base station apparatus 10 establishes synchronization based on this 1PPS, so that synchronization timing can be established between communication apparatuses included in the mobile communication system 1. .

  Hereinafter, the function of the base station apparatus 10 used in the mobile communication system 1 having the above configuration will be described in detail.

  FIG. 2 is a diagram illustrating functional blocks of the base station apparatus 10. As shown in the figure, the base station device 10 functionally includes three GPS receivers 11 (GPS receiver 11-A, GPS receiver 11-B, GPS receiver 11-C), and each Three synchronization timing generation units 12 (a synchronization timing generation unit 12-A, a synchronization timing generation unit 12-B, and a synchronization timing generation unit 12-C) corresponding to the GPS receiver 11, a synchronization control unit 13, and radio signal transmission / reception The unit 14 and the signal transmitting / receiving unit 15 are included. The synchronization control unit 13 further includes a synchronization signal switching unit 13a and a timing shift detection unit 13b, the radio signal transmission / reception unit 14 includes a synchronization timing acquisition unit 14a, and the signal transmission / reception unit 15 includes a synchronization timing acquisition unit 15a. Composed.

  The GPS receiver 11 receives the GPS signal as a synchronization signal and outputs a timing signal corresponding to the GPS signal. This timing signal is 1 PPS here.

  The synchronization timing generation unit 12 performs a process of generating a synchronization timing (synchronization timing generation process) based on the timing signal input from the GPS receiver 11. FIG. 3 is an explanatory diagram of a specific example of the synchronization timing generation processing. As shown in the figure, the timing signal output from the GPS receiver 11 is a pulse signal every second. In synchronization with the head of the pulse signal, the synchronization timing generator 12 generates the timing (synchronization timing) of the transmission (Tx) and reception (Rx) time slots. Here, the base station apparatus 10 performs TDD (time division duplex) that divides transmission and reception on the time axis. That is, the base station apparatus 10 exchanges transmission and reception every predetermined number of time slots (three time slots in FIG. 3). In addition, the base station apparatus 10 makes transmission and reception communication speeds asymmetric, and the length of the time slot on the time axis differs between transmission and reception. The synchronization timing generation unit 12 inputs the generated synchronization timing to the synchronization control unit 13.

  The synchronization control unit 13 establishes synchronization with another communication device with reference to a GPS signal (synchronization signal) received by any GPS receiver 11. Specifically, the synchronization control unit 13 synchronizes with other communication devices included in the mobile communication system 1 based on the synchronization timing input from any of the plurality of synchronization timing generation units 12. Establish. More specifically, the synchronization control unit 13 selects one synchronization timing generation unit 12 from the plurality of synchronization timing generation units 12, and transmits the synchronization timing input from the selected synchronization timing generation unit 12 as a radio signal transmission / reception. Output to the unit 14 and the signal transmitting / receiving unit 15. As will be described later, the wireless signal transmission / reception unit 14 and the signal transmission / reception unit 15 transmit a communication signal in accordance with the input synchronization timing.

  The timing shift detection unit 13b detects that there is a timing shift in the synchronization timing input from the synchronization timing generation unit 12. That is, it detects that there is a timing shift in the timing signal input from the GPS receiver 11 to the synchronization timing generator 12. The synchronization signal switching unit 13a switches the synchronization timing generation unit 12 selected by the synchronization control unit 13 when the timing shift detection unit 13b detects that there is a timing shift in the timing signal. That is, the synchronization signal switching unit 13a switches the device that receives the synchronization signal used as a reference for establishing synchronization by the synchronization control unit 13 to a device other than the GPS receiver 11 that has been used as a reference. Details of these will be described later.

  The radio signal transmission / reception unit 14 receives a communication signal to be transmitted to the mobile station device 30 from a communication control unit (not shown). The wireless signal transmission / reception unit 14 wirelessly transmits the input communication signal at a timing according to the synchronization timing input from the synchronization control unit 13. That is, the radio signal transmission / reception unit 14 matches the transmission time of each time slot included in the communication signal input from the communication control unit with the synchronization timing input from the synchronization control unit 13. Further, the radio signal transmission / reception unit 14 receives a communication signal that has arrived from the mobile station device 30 or another base station device 10 and outputs the communication signal to the communication control unit.

  The synchronization timing acquisition unit 14a detects the time slot of the communication signal received by the radio signal transmission / reception unit 14, and among the received communication signals, the notification signal transmitted by the other base station apparatus 10 The synchronization timing established by the base station apparatus 10 is acquired. That is, the other base station apparatus 10 establishes a synchronization timing similarly to the base station apparatus 10 and transmits a communication signal at a timing according to the established synchronization timing. Therefore, the synchronization timing acquisition unit 14a acquires the timing according to the received communication signal, that is, the reception timing indicated by the reception time of each time slot included in the received communication signal, and the synchronization timing (others) of the received communication signal Is output to the synchronization control unit 13 as communication device establishment synchronization timing).

  Note that the radio signal transmission / reception unit 14 may receive broadcast signals from a plurality of base station devices 10 depending on the positional relationship with other base station devices 10. In this case, each broadcast signal is identified from which base station device 10 is received by the base station device identification information included in the broadcast signal. The synchronization timing acquisition unit 14 a acquires the other communication apparatus establishment synchronization timing for each base station apparatus 10 and outputs the acquired other communication apparatus establishment synchronization timing to the synchronization control unit 13.

  The signal transmission / reception unit 15 receives a communication signal to be transmitted to the exchange 20 from a communication control unit (not shown). The signal transmission / reception unit 15 transmits the input communication signal at a timing according to the synchronization timing input from the synchronization control unit 13. That is, the signal transmission / reception unit 15 matches the transmission time of each time slot included in the communication signal input from the communication control unit with the synchronization timing input from the synchronization control unit 13. Further, the signal transmission / reception unit 15 receives the communication signal transmitted by the exchange 20 and outputs it to the communication control unit.

  The synchronization timing acquisition unit 15a detects the time slot of the communication signal received by the signal transmission / reception unit 15, and acquires the synchronization timing established by the exchange 20 from the received communication signal. That is, the exchange 20 also establishes the synchronization timing as described above, and transmits a communication signal at a timing according to the established synchronization timing. Therefore, the synchronization timing acquisition unit 15a acquires the timing according to the received communication signal, that is, the reception timing indicated by the reception time of each time slot included in the received communication signal, and the synchronization timing (others) of the received communication signal Is output to the synchronization control unit 13 as communication device establishment synchronization timing).

  The timing deviation detection unit 13b is configured to receive a timing corresponding to a communication signal (communication signal reception timing) indicated by one or more other communication device establishment synchronization timings input from at least one of the synchronization timing acquisition unit 14a and the synchronization timing acquisition unit 15a. ) And the synchronization timing established by the synchronization control unit 13, the synchronization timing generation unit is detected from the GPS receiver 11 by detecting that there is a timing deviation in the synchronization timing input from the synchronization timing generation unit 12. 12 detects that there is a timing shift in the timing signal input to 12.

  Hereinafter, the timing shift detection process by the timing shift detector 13b will be described in more detail. In the following, for the sake of simplicity, the description will be made assuming that the timing shift is detected using only the other communication apparatus establishment synchronization timing established by the other base station apparatus 10 acquired by the synchronization timing acquisition unit 14a.

  The timing deviation detection unit 13b compares the synchronization timing established by the synchronization control unit 13 with one or a plurality of other communication device establishment synchronization timings, thereby causing a timing deviation in the timing signal output from the GPS receiver 11. Detect that there is. When a plurality of other communication device establishment synchronization timings are input, the timing deviation detection unit 13b has the synchronization timing established by the synchronization control unit 13 different from any of the plurality of other communication device establishment synchronization timings. If it is, it is determined that there is a timing shift in the timing signal. Thus, the timing shift detector 13b detects that there is a timing shift in the timing signal.

  FIG. 4 is an explanatory diagram showing a specific example of the timing shift detection process. In the figure, the synchronization timing established by the synchronization control unit 13 (generated based on the GPS signal received by the GPS receiver) is three other communication apparatus establishment synchronization timings (base station apparatus A, base station apparatus B). And those established by the base station apparatus C). In such a case, the timing shift detection unit 13b determines that there is a timing shift in the timing signal output from the GPS receiver 11 of the base station apparatus 10 itself.

  By performing the timing shift detection process as described above, the timing shift detector 13b detects that there is a timing shift in the timing signal. When the timing shift detector 13b detects that there is a timing shift in the timing signal, the synchronization signal switching unit 13a sets a device that receives a synchronization signal as a reference for establishing synchronization by the synchronization control unit 13 until then. The device is switched to a device other than the GPS receiver 11 that has been used as a reference (outputs a timing signal in which a timing shift is detected). For example, when a GPS signal received by the GPS receiver 11-A has been used as a synchronization signal, the GPS signal is received by another GPS receiver 11 (GPS receiver 11-B or GPS receiver 11-C). Switch to the GPS signal. That is, when the synchronization timing is established with another communication device according to the generated synchronization timing based on the timing signal output from the GPS receiver 11-A, the other GPS receiver 11 (GPS Based on the timing signal output from the receiver 11-B or the GPS receiver 11-C), the synchronization timing is reestablished according to the generated synchronization timing.

  By switching the GPS receiver 11 that receives the synchronization signal in this way, the synchronization control unit 13 does not attempt to establish synchronization based on synchronization timings that are out of timing.

  Hereinafter, the timing shift detection process in the base station apparatus 10 will be described in more detail again with reference to a process flowchart.

FIG. 5 is a diagram illustrating a processing flow of timing deviation detection processing. The base station apparatus 10, first, on the basis of the 1PPS the GPS receiver 11 is included in the GPS signal is a synchronization signal to be received, to establish synchronization timing _{T G} (S1). Moreover, the base station apparatus 10 acquires the synchronization timing established by the other base station apparatus 10 based on the notification signal received from the other base station apparatus 10 (S2). Here, it is assumed that the synchronization timing acquired in S2 is the synchronization timing T _A , the synchronization timing T _B , and the synchronization timing T _C.

The base station apparatus 10 compares the synchronization timing T _A , the synchronization timing T _B , and the synchronization timing T _C with the synchronization timing T _G, and the synchronization timing T _A , the synchronization timing T _B , and the synchronization timing T _C are all synchronized with the synchronization timing T _C. It is determined whether or not the timing is the same as _G (S3).

If the determination result in S3 is affirmative, the base station apparatus 10 determines that the synchronization timing _TG has not shifted, and returns the process to S1. On the other hand, if the determination result in S3 is negative, the base station apparatus 10 further determines whether only the synchronization timing _TG is different from the others (S4).

If the determination result in S4 is affirmative, the base station device 10 determines that the synchronization timing _TG is shifted, and sends a device that receives a synchronization signal as a reference for establishing synchronization to another GPS receiver 11. Switch (S5). If this switching is successful, the base station apparatus 10 returns the process to S1, and if it fails, the base station apparatus 10 notifies the maintenance center (not shown) of the mobile communication system 1 that a “communication timing abnormality” has occurred (S6). , S7).

  In addition, when switching fails in S5, there are the following cases. That is, there is only one GPS receiver 11 that can be used at the time of switching. When the base station apparatus 10 switches the apparatus that receives the synchronization signal in the process of S5, the switching source, that is, the GPS receiver 11 determined that the timing signal is shifted is stored in the memory as being in failure. To do. Similarly, the GPS receiver 11 indicated by the status signal as being in failure is also stored in the memory as being in failure. In this way, the base station device 10 is configured such that the GPS receiver 11 that is stored in the memory as being in failure is not the switching destination in S5. For this reason, even if the base station apparatus 10 includes a plurality of GPS receivers 11, there may be only one GPS receiver 11 that can be used. In such a case, the switching in S5 fails.

  If the determination result in S4 is negative, the base station device 10 indicates that another communication station device 10 or a “communication timing error” has occurred in the base station device 10 is the maintenance center of the mobile communication system 1. (Not shown) is notified (S7).

  Upon receiving the notification in S7, the maintenance center analyzes the cause of the “communication timing abnormality” and takes appropriate processing. Note that the base station apparatus 10 preferably sends information indicating the determination results of S3, S4, and S6 to the maintenance center. This facilitates the cause analysis of the “communication timing abnormality”.

  When the maintenance center is notified from the base station apparatus 10 to the other base station apparatus 10 that the “communication timing abnormality” has occurred, the maintenance center notifies the base station apparatus 10 in which this “communication timing abnormality” has occurred. Then, the abnormality information indicating that the “communication timing abnormality” has occurred is transmitted. The base station apparatus 10 that has received this abnormality information switches the GPS receiver 11 that receives a synchronization signal as a reference for establishing synchronization, as described above.

  As described above, according to the present invention, the base station device 10 can synchronize with the synchronization timing established based on the timing signal output from the GPS receiver 11 and one or more other communication devices (such as the exchange 20 or the like). The timing signal output from the GPS receiver 11 can be detected based on the timing according to the communication signal transmitted by the base station apparatus 10).

  In addition, when it is detected that the signal output from the GPS receiver 11 has a timing shift, the base station device 10 changes a device that receives a synchronization signal as a reference for establishing synchronization to another device (for example, It becomes possible to switch to another GPS receiver 11).

  The present invention is not limited to the above embodiment. For example, the timing shift detection process can be performed as follows.

  That is, the timing shift detection unit 13 b predicts the timing at which a signal is received by the radio signal transmission / reception unit 14 or the signal transmission / reception unit 15 based on the synchronization timing established by the synchronization control unit 13. The timing shift detection unit 13b determines whether a communication signal is received by the wireless signal transmission / reception unit 14 or the signal transmission / reception unit 15 at the predicted timing. When a communication signal from one or a plurality of base station devices 10 is not received at the predicted timing, the timing shift detection unit 13b is connected to another communication device established by the base station device 10 with the synchronization timing established by the synchronization control unit 13. It is determined that the establishment synchronization timing is different. If the timing shift detector 13b determines that these are different, the timing shift detector 13b determines that there is a timing shift in the timing signal. Even in this case, it is possible to detect a timing shift of the timing signal.

  In the above embodiment, when switching the device that receives the synchronization signal, the GPS signal is switched to another GPS receiver 11, but the communication signal receiving device that receives the communication signal received from the exchange 20, for example, is switched. Also good. In this case, the synchronization control unit 13 establishes synchronization timing with other communication devices included in the mobile communication system 1 based on the other communication device establishment synchronization timing acquired based on the communication signal. Become.

It is a figure which shows the system configuration | structure of the mobile communication system which concerns on embodiment of this invention. It is a figure which shows the functional block of the base station apparatus which concerns on embodiment of this invention. It is explanatory drawing of the synchronous timing generation process which concerns on embodiment of this invention. It is explanatory drawing of the timing shift detection process which concerns on embodiment of this invention. It is a figure which shows the processing flow of the base station apparatus which concerns on embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Mobile communication system, 10 Base station apparatus, 11 GPS receiver, 12 Synchronization timing generation part, 13 Synchronization control part, 13a Synchronization signal switching part, 13b Timing deviation detection part, 14 Radio signal transmission / reception part, 14a Acquisition of synchronization timing Unit, 15 signal transmission / reception unit, 15a synchronization timing acquisition unit, 20 exchange, 30 mobile station device, 40 GPS satellite.

Claims (3)

A base station apparatus used in a mobile communication system,
The mobile communication system includes a plurality of communication devices including the base station device,
Each of the communication devices receives a synchronization signal as a reference for establishing synchronization, establishes a synchronization timing with the other communication devices based on the synchronization signal, and transmits a communication signal at the established synchronization timing. Send and receive,
The base station device
A GPS signal is received as the synchronization signal, and a plurality of GPS receivers that output timing signals according to the GPS signal are provided.
Synchronization establishment means for establishing synchronization timing with the other communication device based on a timing signal output from any of the plurality of GPS receivers;
A communication signal receiving means for receiving the communication instrumentation placed al communication signals,
Other communication apparatus establishment synchronization timing for acquiring another communication apparatus establishment synchronization timing that is a synchronization timing established by the communication apparatus that has transmitted the communication signal based on a timing according to a communication signal received by the communication signal receiving means Acquisition means;
Synchronization timing established by the synchronization establishment means, when are different from any other communication device establishing synchronization timing of the plurality of communication apparatuses acquired by the other communication device establishes synchronization timing acquisition means, the timing offset to said timing signal Timing deviation detection means for detecting the presence of
When the timing shift detecting means detects that the timing signal has a timing shift, the synchronization is switched to a GPS receiver other than the GPS receiver that has output the timing signal from which the timing shift has been detected. Signal receiving device switching means ,
including,
A base station apparatus. The base station apparatus according to claim 1,
The mobile communication system further comprises a maintenance center,
When the timing deviation detection means detects that there is a timing deviation in the other communication apparatus establishment synchronization timing of any of the plurality of communication apparatuses, the timing deviation of the communication apparatus in which the timing deviation is detected is detected. Notification means for notifying the maintenance center,
The base station apparatus further comprising: A synchronization timing deviation detection method for detecting a synchronization timing deviation in a base station device used in a mobile communication system,
The mobile communication system includes a plurality of communication devices including the base station device,
Each of the communication devices receives a synchronization signal as a reference for establishing synchronization, establishes a synchronization timing with the other communication devices based on the synchronization signal, and transmits a communication signal at the established synchronization timing. Send and receive,
The synchronization timing shift detection method is:
Synchronization that establishes synchronization timing with another communication device based on a timing signal output from a GPS receiver that receives a GPS signal as the synchronization signal and outputs a timing signal corresponding to the GPS signal An establishment step;
A communication signal receiving step of receiving a communication signal from the communication device;
Based on the timing according to the communication signal received in the communication signal receiving step, the other communication device establishment synchronization timing is obtained to obtain the other communication device establishment synchronization timing that is the synchronization timing established by the communication device that has transmitted the communication signal. Steps,
When the synchronization timing established in the synchronization establishment step is different from any of the other communication device establishment synchronization timings of the plurality of communication devices acquired in the other communication device establishment synchronization timing acquisition step, there is a timing shift in the timing signal. A timing shift detection step for detecting the presence,
When the timing signal is detected to have a timing error in the timing error detection step, the synchronization signal is switched to another GPS receiver other than the GPS receiver that has output the timing signal from which the timing error has been detected. A signal receiving device switching step ;
including,
A synchronization timing shift detection method characterized by the above.

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