JP2008136164A - Communication base station apparatus and synchronization control method of communication base station apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To maintain synchronization between base stations even if a disaster such as an earthquake occurs and a server connected to a host network is disabled due to the disaster, whereby interference between the base stations can be prevented and communication can be established. <P>SOLUTION: A communication base station apparatus 1 can control synchronization between base stations suitably for the respective stations, based on shake information of an earthquake collected by the base stations. In addition, even if a synchronization reference signal from a host network is lost due to stop of function of a server, the apparatus can autonomously control synchronization between the base stations and assure the necessary number of communication lines. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a communication base station apparatus and a communication base station apparatus synchronization control method.

  In TDMA (time division multiplexing) wireless communication such as PHS (Personal Handy-phone System), a plurality of base stations operate in synchronization so that they operate at the same timing. Normally, all the base stations connected to the network use the timing based on the synchronization signal from the higher level network to which the base station is connected to transmit and receive communication signals while maintaining synchronization. In TDMA (Time Division Multiplex) wireless communication, a single frequency is divided and shared in the time axis direction between a base station and a plurality of users connected to the base station, and at predetermined time intervals (time slots). , Hereinafter referred to as a slot), control is performed to allocate a line to each user. FIG. 2 shows a communication frame in the case of performing time division multiplexing control in which the time axis is divided into 8 slots and the same slot is assigned to a specific user for each frame. In this case, four lines 1 to 4 can be used in pairs of a transmission slot and a reception slot. Normally, one line of slot A out of the four lines is used as a control physical channel.

  By the way, in areas where there is a large amount of communication calls, there is a growing need to accommodate a larger number of lines, and by arranging a plurality of base stations at the same location, there are areas where a greater number of lines are accommodated. FIG. 1 shows an image when a plurality of base stations are arranged at the same location. In this example, since the base stations 1-1 and 1-2 can receive radio waves from each other's base stations, if the communication frames shown in FIG. Therefore, the interference wave is transmitted to the other base station (which becomes an interference wave for the other base station), and normal communication cannot be performed. Therefore, as described above, the base stations maintain the synchronization between the base stations based on the synchronization reference signal from the upper network, and are controlled so that the collision of the slot timings in TDMA does not occur.

  In addition, in the event of a disaster such as an earthquake, many users call all at once to ensure urgent contact and safety, so communication exceeding the line capacity is required, and as a result, a state called communication congestion that prevents communication is generated. . In this case, data communication such as e-mail falls into a situation where it is difficult to communicate due to the influence of congestion.

Patent Document 1 listed below is a mobile phone having an Internet connection function and an e-mail transmission / reception function, and includes one or more types of means for detecting an abnormal situation or an emergency situation, and information on the detected abnormal situation or emergency situation. A technology related to a mobile phone that receives and transmits a message is disclosed. Further, in Patent Document 2 below, the base station transmits a communication restriction message for selectively prohibiting transmission via a broadcast channel to the mobile station, so that the mobile station prohibits transmission and “location registration”. A technique for transitioning to a regulation standby mode without performing the process is disclosed.
JP 2005-311995 A By the way, the PHS base station apparatus is small and light because of its small output, and is often installed outdoors such as a utility pole or the rooftop of a building. For this reason, it is more susceptible to external influences such as wind and earthquakes compared to devices installed indoors, and the failure rate is high.

  For this reason, some conventional base station apparatuses include a maintenance diagnosis unit in the base station apparatus. When the maintenance diagnosis unit monitors the internal state of the base station apparatus and detects the occurrence of a failure, it attempts to recover autonomously. The maintenance diagnosis unit also has a function of notifying the base station management device, which is a higher-level device, of information related to the occurrence or recovery of a failure.

  As described above, in the event of a disaster such as an earthquake, a state in which communication called congestion occurs is impossible because many users call all at once for emergency communication and ensuring safety.

Furthermore, synchronization between base stations cannot be maintained when a server connected to a higher level network fails due to an earthquake or the like. As a result, a large amount of interference occurs between the base stations, and communication is substantially impossible.

  In addition, the base station does not have a function of detecting shaking such as an acceleration sensor, and information relating to shaking is collected from the Japan Meteorological Agency or the like via an upper network. Until the synchronization reference is restored, autonomously predictive inter-base station synchronization holding control cannot be performed at all. Therefore, despite the occurrence of a disaster and great damage, many people cannot be contacted for rescue or safety confirmation and are isolated.

  The present invention has been made in view of the above-described conventional problems, and in particular, environmental information in which the base station apparatus collected by the base station apparatus itself at the time of a disaster that causes the base station apparatus to shake, such as an earthquake or a typhoon, An object of the present invention is to provide a base station apparatus and a base station apparatus synchronization control method capable of performing inter-base station synchronization control suitable for the base station apparatus on the basis of information on shaking and securing a communication line even in the event of a disaster. And

  In order to achieve the above object, a communication base station apparatus according to the present invention is used in a communication system in which a plurality of communication terminals and a plurality of communication base station apparatuses communicate with each other in a time division multiplexing manner. An environment information acquisition unit that acquires environment information, a synchronization unit that controls synchronization between the communication base station apparatuses, and a synchronization maintenance control unit that controls the synchronization unit according to the acquired environment information. And

  In one aspect of the present invention, the synchronization maintaining control unit determines whether to start according to the acquired environment information.

  In one aspect of the present invention, a synchronization signal detection unit that detects a synchronization signal from another device is provided, and the synchronization unit detects a synchronization signal generated by the synchronization signal detection unit when the synchronization maintenance control unit is activated. The synchronization target is changed in accordance with the detection state.

  Further, in one aspect of the present invention, when the synchronization maintaining control unit is activated, the synchronization unit sets the synchronization source as its own base station when no synchronization signal is detected by the synchronization signal detection unit. It is characterized by.

  And it comprises the random number control means which determines whether a synchronization origin is made into a self-base station using a random number, It is characterized by the above-mentioned.

  In one aspect of the present invention, the environment information acquisition unit is a vibration sensor that detects vibration information.

  In one aspect of the present invention, the vibration information includes a seismic intensity at the time of occurrence of the earthquake.

  Further, the present invention is a synchronization control method in a communication system including a plurality of communication base station apparatuses that communicate with a plurality of communication terminals in a time division multiplexing method, and an environment for acquiring environment information of the communication base station apparatus The information acquisition step includes a synchronization step for controlling the synchronization between the communication base station devices, and a synchronization maintenance control step for controlling the synchronization means according to the acquired environment information.

  According to the synchronization control method for a base station apparatus and a communication base station apparatus in the present invention, it is possible to perform inter-base station synchronization maintaining control suitable for the base station based on the earthquake shake information collected by the base station itself. . Further, even when the synchronization reference signal from the upper network is lost due to a server function stop or the like, the synchronization maintaining control between base stations can be autonomously performed, and the number of lines can be secured. As a result, the line can be secured and urgent communication and safety confirmation can be performed.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment of the invention will be described with reference to the drawings. FIG. 3 is a functional block diagram of the base station apparatus 1. The base station apparatus 1 includes an external interface unit 11, a signal processing unit 12, a radio unit 14, a synchronization maintenance control unit 16, an acceleration calculation unit 17, and an acceleration sensor 18. The control unit 19 includes a synchronization detection unit 191, a synchronization control unit 192, and a status determination unit 193. Furthermore, it includes an operation management unit, a radio control unit, and a line control unit (not shown), and includes a CPU, a memory, and the like, and performs control related to the operation of the entire base station apparatus 1.

    The wireless communication unit 14 includes an antenna 15 and is connected to the external interface unit 11 via the signal processing unit 12. The radio unit 14 receives a signal from each communication device 2 received by the antenna 15, performs demodulation, error correction, and the like in the signal processing unit 12, converts the data into a data signal such as a packet or voice, and then transmits the data The signal is output to the external interface unit 11. The signal processing unit 12 performs error correction and modulation processing on a plurality of data signals such as packets and voices input from the external interface unit 11 and sends the data signals to the radio unit 14. The wireless unit 14 transmits a data signal that can be transmitted as a radio wave to each communication device 2 via the antenna 15.

  The external interface unit 11 is connected to a communication network via an ISDN (Integrated Service Digital Network) line, Ethernet (registered trademark), or the like, and connects the base station apparatus 1 and a communication network that is an upper network to each other. The interface unit 11 outputs various data such as packets input from the communication network to the signal processing unit 12 in accordance with instructions from the control unit 19. In addition, data such as a plurality of packets input from the signal processing unit 12 is output to the communication network.

  Further, the base station apparatus 1 includes a maintenance diagnosis unit (all not shown) including a failure monitoring unit (tilt notification unit), an antenna diagnosis unit, a line diagnosis unit, and a tilt diagnosis unit. The maintenance diagnosis unit monitors the operating state of each functional block of the base station device 1 and attempts to recover autonomously when it detects the occurrence of a failure. Further, as necessary, the base station management device that is a host device or an online center including the base station management device is notified of information related to the occurrence or recovery of a failure. The failure monitoring unit is connected to the antenna diagnosis unit, the line diagnosis unit, and the inclination diagnosis unit, monitors the diagnosis result input from each diagnosis unit, and notifies the base station management device etc. of information related to the failure etc. as necessary. To do. The antenna diagnosis unit is connected to the failure monitoring unit and to the signal processing unit 12 and the radio unit 14. And while diagnosing the state of the signal processing part 12, the radio | wireless part 14, and the antenna 15, a diagnostic result is output to a failure monitoring part. The line diagnosis unit is connected to the failure monitoring unit and to the external interface unit 11. Then, the state of the line connected to the base station apparatus 1 is diagnosed, and the diagnosis result is output to the failure monitoring unit. In addition, the maintenance diagnosis unit notifies the information on the gravitational acceleration vector acquired by the acceleration sensor 18 and calculated by the acceleration calculation unit 17, which will be described later, to the base station management device that is the host device or an online center including the base station management device. To do.

  The acceleration sensor 18 is a vibration sensor that detects vibration information. The acceleration calculation unit 17 calculates a gravitational acceleration vector applied to the base station apparatus 1 measured by the acceleration sensor 18 and acquires a correspondence with the time axis of the calculated gravitational acceleration vector. That is, a change in the time direction of the gravitational acceleration vector is acquired. Further, the acquired data on the change in the time direction of the gravitational acceleration vector is stored in a storage unit (not shown). The acceleration sensor 18 is fixed to the base station apparatus 1 and measures the acceleration applied to the base station apparatus 1. The acceleration sensor 18 is a sensor that measures the magnitude of acceleration applied to the attached object. Specifically, the acceleration sensor 18 measures the magnitude and direction of the gravitational acceleration (gravity acceleration vector) and uses the acceleration sensor 18 as a reference. The x, y, and z direction components of the gravitational acceleration vector in the coordinate system are acquired. In the present embodiment, each component of the gravitational acceleration vector measured by the acceleration sensor 18 is used as an acceleration applied to the base station apparatus 1. Here, when the base station apparatus shakes due to an earthquake or the like, the acceleration acquired by the acceleration calculating unit 17 may be an average value of values measured by the acceleration sensor 18 at a predetermined sampling period. By so doing, variations in measurement values related to the gravitational acceleration vector by the acceleration sensor 18 are reduced, and the measurement accuracy is improved.

  The synchronization maintaining control unit 16 determines whether or not to activate the synchronization maintaining control for the base station apparatus 1 based on the gravitational acceleration vector calculated by the acceleration calculating unit 17, and activates the synchronization maintaining operation when the predetermined shaking is exceeded. .

  Here, functional blocks related to the synchronization maintaining control operation according to the base station apparatus 1 will be described. As described above, the synchronization maintaining operation is started when the synchronization maintaining control unit 16 determines that the shaking obtained by the acceleration sensor 18 and the acceleration calculating unit 17 exceeds a predetermined shaking. The synchronization detection unit 191 determines whether there is a synchronization reference signal from the upper network, and further monitors the control physical channel in signals from other base stations. The control physical channel refers to the A slot in the communication frame of FIG. The status determination unit 193 detects a status indicating the synchronization state transmitted by the other base station from the control physical channel received by the synchronization detection unit 191. Furthermore, the status of the own base station is also determined and the status is raised to the control physical channel to be transmitted. The synchronization control unit 192 synchronizes its own base station according to the synchronization signal detected by the synchronization detection unit 192. Specifically, if a synchronization reference signal can be received from the higher level network, the reference signal can be received. If synchronization cannot be received from the higher level network but synchronization by the control physical channel of another base station is possible, synchronization based on the control physical channel is possible. I do. In the status determination performed by the status determination unit 193, status A: when a reference for synchronization is obtained from a higher-level network. Status B: The case where the reference to synchronize from the upper network is lost and the base station is subordinately synchronized with another base station. Status C: There are three cases in which the base station that is subordinately synchronized is further subordinately synchronized. If the status of another base station cannot be detected, the base station loses synchronization and determines that it is in a function stop state. If the base station is in the same state, the status is not raised.

Next, the synchronization holding control operation of the base station apparatus 1 will be described based on the flowchart of FIG.
First, a base station is installed and normal operation is performed (S10). When a shake such as an earthquake occurs, it is determined whether the gravitational acceleration vector applied to the base station calculated by the acceleration calculation unit 17 is equal to or greater than a specified value (S20). If it is not over the limit, return to normal operation. If it exceeds the limit, the synchronization maintaining control unit 16 is activated (S30). Then, the control unit 19 is instructed to detect the synchronization signal information by the synchronization detection unit 191. If the synchronization signal can be received from the upper network (S40 Yes), the status determination unit 193 determines the status of the own base station, and transmits the status through the control physical channel transmitted from the own base station (S50, S60). . Then, the synchronization control unit 192 continues to maintain the inter-base synchronization maintaining operation (S70). Thereafter, if a holding operation cancellation instruction is received from the upper network (S80 Yes), the normal operation is resumed (S90). If there is no instruction to cancel the holding operation in S80 (No), the process returns to S70, and the inter-base synchronization holding operation is continuously maintained.

  In S40, when the synchronization signal cannot be received from the upper network (No in S40), the synchronization detector 191 monitors the signal of the control physical channel of another base station (S100). And it is confirmed whether the status determination part 193 can determine the status of another base station (S110). If it can be confirmed (Yes), the synchronization control unit 192 starts synchronization control using the control physical channel of the other base station, and at the same time, the status determination unit 193 determines the status of the other base station by determining the synchronization level (S120). If the status of the other base station can be determined (Yes), then the status determination unit 193 transmits the status of the own base station through the control physical channel transmitted from the own base station (S130). Then, the control unit 19 constructs a network with the base station that is the source of synchronization (S140). As a result, a local network can be formed with the synchronization source base station, and communication between users in the cells of the base stations becomes possible. Subsequently, the synchronization detection unit 191 checks whether or not the synchronization reference signal from the host network can be detected. If the synchronization reference signal can be detected (Yes in S150), the normal operation is restored (S90). If it cannot be detected (No at S150), the control unit 19 checks whether there is an instruction to cancel the holding operation from the upper network (Yes at S160), and returns to normal operation (S90). If not (S160 No), the process returns to S150. If the status of the other base station cannot be confirmed in S110, the control unit 19 determines that it is impossible to continue the operation, and the operation ends.

  Subsequently, a second embodiment of the present invention will be described with reference to the drawings. In the second embodiment, when the status of the other base station cannot be confirmed in S110 of FIG. 4 in the first embodiment, the communication function is performed without using the own base station as a synchronization source instead of ending the operation. Recovery. As shown in FIG. 6, when the status of another base station cannot be confirmed in S110, a process called random synchronization control (S200) is performed.

  In urban areas where multiple communication infrastructures are in place, there is no problem even if the function is temporarily stopped if it is difficult to restore the communication function as in the first embodiment. There is a case where only one type of communication infrastructure is provided, and in such an area, it is given priority to restore the communication function of the damaged communication infrastructure in the event of a disaster. The second embodiment assumes such a situation.

In the second embodiment, a random number control unit 194 is provided in the control unit 19 as shown in FIG. The random number control unit 194 determines whether or not the own base station is a synchronization source using a random number.
The random number control unit 194 includes a predetermined value setting unit (not shown), a random number generation unit, and a random number comparison unit. The predetermined value setting unit stores a predetermined value Rx in a memory (not shown) in advance. The predetermined value Rx is not limited to one value, and a different range may be set according to the earthquake damage status (seismic intensity). For example, when the seismic intensity is 4 to 5, 0 <Rx <100, and when the seismic intensity is 6 to 7, 0 <Rx <1000. The random number generation unit generates a random number R according to an instruction from the control unit 19. The random number comparison unit compares the random number R obtained by the random number generation unit with a predetermined value Rx to compare whether R is included in Rx, and if the random number R is included in the predetermined value Rx, Decide to be. Specifically, if the random number R is included in the predetermined value Rx, the synchronization control unit 192 is instructed to generate a synchronization burst.

  By using a random number as described above, it is possible to vary the timing for determining that each base station apparatus is a synchronization source, and to prevent a plurality of base station apparatuses from simultaneously becoming a synchronization source. In addition, by varying the range of the predetermined value Rx according to the damage situation, the time until the restoration of the communication function is shortened as the damage situation becomes vast when the synchronization by the upper network or another base station apparatus cannot be obtained. can do.

Next, random synchronization control processing (S200) in the synchronization holding control operation of the base station apparatus 1 based on the second embodiment will be described based on the flowchart of FIG.
If the status of the other base station cannot be confirmed in S110 of FIG. 6 (No), it is confirmed whether or not a timer (not shown) is started (S210). If not started (No), the timer is started (S220), and the next process is started. This timer is included in the control unit 19 and is used for waiting to some extent whether the synchronization operation by the higher-level network or the synchronization operation from another base station (which originally becomes the synchronization reference station) is not restored. For example, wait for about 10 to 15 minutes. If the timer has started (S210 Yes), the control unit determines whether or not a predetermined time has elapsed (S230). If the predetermined time has not elapsed (No), the process jumps to “A” in FIG. 6 (before S40) and proceeds to a flow for confirming the synchronization information from the upper network. On the other hand, when the predetermined time has elapsed (Yes), the predetermined value setting unit in the random number control unit 194 sets the predetermined value Rx (S240). At this time, the predetermined value setting unit sets a value in a different range according to the earthquake damage status (seismic intensity) based on the gravitational acceleration vector calculated by the acceleration calculation unit 17. Next, the random number generator in the random number controller 194 generates a random number R (S250). Then, the random number comparison unit in the random number control unit 194 compares whether the random number R obtained by the random number generation unit is included in Rx with respect to the predetermined value Rx (S260). If the random number R is not included in the predetermined value Rx (No), the process returns to S250. On the other hand, if the random number R is included in the predetermined value Rx (Yes), the random number comparison unit determines that the own base station is a synchronization source and instructs the synchronization control unit 192 to generate a synchronization burst. The synchronization control unit 192 generates and transmits a synchronization burst in accordance with an instruction from the random number comparison unit (random number control unit) (S270). At this time, the synchronization burst may be transmitted a plurality of times instead of once.

  Subsequently, the synchronization detector 192 starts monitoring the control physical channel of another base station (S280). And it is confirmed whether the status determination part 193 can determine the status of another base station (S290). If it can be confirmed that the status of the other base station is dependent on the synchronization (Yes), then the status determination unit 193 transmits the synchronization base station (synchronization reference station (synchronization) through the control physical channel transmitted from the own base station. A status indicating that it is a source) is transmitted (S310). On the other hand, in S290, when the status of the other base station is not dependent on synchronization (No), that is, when the control physical channel cannot receive a synchronization signal (synchronization burst) from another base station, Is determined to be a synchronization reference station, the process jumps to FIG. 6A (before S40) and proceeds to a flow for confirming synchronization information from the higher-level network.

  After the process of S310, the control unit 19 constructs a network with another base station that becomes a synchronization dependent station (S320), and performs communication within the local network. As a result, a local network can be formed with a plurality of base stations including its own base station, and users in the cells of the base stations can communicate.

Further, the control unit 19 periodically determines whether or not it is possible to return to the normal operation mode, and if possible, returns to the normal operation mode (S330). Specifically, the determination is made according to whether or not the synchronization signal from the network can be received and whether or not there is an instruction to cancel the inter-base station synchronization holding control.

  According to the base station apparatus and the base station apparatus synchronization control method described above, it is possible to perform synchronization holding control suitable for the base station based on the shake information collected by the base station itself. In addition, it is possible to secure a line at the time of a disaster by performing inter-base station synchronization holding control.

It is an arrangement image figure when a plurality of base stations are arranged. It is a figure of the communication frame which concerns on embodiment of this invention. It is a functional block diagram of the base station apparatus which concerns on the 1st Embodiment of this invention. It is a flowchart which shows the operation | movement concerning the synchronous holding | maintenance control of the base station apparatus which concerns on the 1st Embodiment of this invention. It is a functional block diagram of the base station apparatus which concerns on the 2nd Embodiment of this invention. It is a flowchart which shows the operation | movement concerning the synchronous holding | maintenance control of the base station apparatus which concerns on the 2nd Embodiment of this invention. It is a part of flowchart which shows the operation | movement concerning the synchronous holding | maintenance control of the base station apparatus which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Base station apparatus, 2 External communication apparatus, 11 External I / F part, 12 Signal processing part, 14 Radio part, 15 Antenna, 16 Synchronization maintenance control part, 17 Acceleration calculation part, 18 Acceleration sensor, 19 Control part, 191 Synchronization detection unit, 192 Synchronization control unit, 193 Status determination unit, 194 Random number control unit.

Claims (8)

A communication base station apparatus in a communication system in which a plurality of communication terminals and a plurality of communication base station apparatuses communicate with each other in a time division multiplexing method,
Environmental information acquisition means for acquiring environmental information of the communication base station device;
Synchronization means for controlling synchronization between the communication base station devices;
Synchronization maintenance control means for controlling the synchronization means according to the acquired environment information;
A communication base station apparatus comprising: The synchronization maintenance control means determines whether to start according to the acquired environment information;
The communication base station apparatus according to claim 1. A synchronization signal detecting means for detecting a synchronization signal from another device;
The synchronization means, when the synchronization maintenance control means is activated, to change the synchronization source target according to the detection state of the synchronization signal by the synchronization signal detection means;
The communication base station apparatus according to claim 1 or 2. The synchronization means is a case where the synchronization maintenance control means is activated, and when the synchronization signal is not detected by the synchronization signal detection means, the synchronization source is the base station,
The communication base station apparatus according to any one of claims 1 to 3, wherein: Comprising a random number control means for determining whether or not to set the synchronization source as a base station using a random number;
The communication base station apparatus according to claim 4. The communication base station apparatus according to claim 1, wherein the environment information acquisition unit is a vibration sensor that detects vibration information. The communication base station apparatus according to claim 6, wherein the vibration information includes a seismic intensity when an earthquake occurs. A synchronization control method in a communication system comprising a plurality of communication base station devices that communicate with a plurality of communication terminals in a time division multiplexing method,
Environmental information acquisition step of acquiring environmental information of the communication base station device;
A synchronization step for controlling synchronization between the communication base station devices;
A synchronization maintaining control step for controlling the synchronization means according to the acquired environment information;
A synchronization control method for a communication base station apparatus, comprising:

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