JP2006005843A - Communication control method and base station device utilizing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication control method for continuing communication between terminal devices connected to a base station device even in the situation that trouble occurs in the communication, and the base station device utilizing the communication control method. <P>SOLUTION: A routing control section 20 controls communication so that a terminal device 10 and a communication apparatus 16 can communicate with each other via a network 14. An IF section 22 is an interface between the routing control section 20 and the network 14. A storage section 26 stores information to be used for processing relating to an address in the routing control section 20. A fault detection section 24 monitors a state of the network 14 such as, for example, connection with a non-illustrated router connected to the network 14. If occurrence of a fault in the network 14 is detected, the routing control section 20 switches processing, in a radio communication section 18, relating to the address on the terminal device 10. Further, the routing control section 20 and the radio communication section 18 notify the terminal device 10 of switching to intra-area routing. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a communication control technique, and more particularly, to a communication control method for changing communication control when a predetermined state is reached, and a base station apparatus using the communication control method.

In a wireless communication system such as a mobile communication system, generally, a base station device connects a terminal device by wireless communication while connecting a network by wired communication. The terminal device communicates with the network via the base station device. Further, the base station apparatus is connected to an exchange or another base station apparatus via a network, or connected to the Internet. In this way, the base station device provides the voice communication service and data communication service to the terminal device. However, if a failure occurs in a part of the network connected to the base station apparatus, the terminal apparatus and the base station apparatus can communicate with each other, but the entire wireless communication system can provide voice communication services and data to the terminal apparatus. Communication service cannot be provided. For this purpose, a technology is proposed that secures communication between terminal devices by providing a pseudo master station inside the base station device and switching the communication target of the terminal device from the network to the pseudo master station if a failure occurs on the network side. (For example, refer to Patent Document 1).
Japanese Patent Laid-Open No. 6-209596

  Under such circumstances, the present inventor has come to recognize the following problems. When the wireless communication system is a mobile communication system, a terminal apparatus connected to one base station apparatus changes with time due to movement of the terminal apparatus. However, if the wireless communication system is not based on the movement of the terminal device as in a FWA (Fixed Wireless Access) system, the terminal device connected to one base station device is generally fixed. When telephone communication is performed between terminal apparatuses connected to different base station apparatuses, telephone communication is disconnected if a failure occurs on the network side.

  On the other hand, when telephone communication is made between terminal devices connected to the same base station device, even if a failure occurs on the network side, the communication path between each terminal device and the base station device is normal. Therefore, it is desirable to continue telephone communication. Therefore, it is only necessary to switch the communication in the form via the network to the communication not in the network due to a failure on the network side. By switching the control for such communication, some communication is continued even after the occurrence of the failure. However, in a wireless communication system that does not presuppose movement of a terminal device such as an FWA system, control switching in communication such as handover is not executed. Therefore, the function of notifying the terminal device of the switching is often omitted in order to improve transmission efficiency and simplify the operation sequence. In such a case, even if the control for communication is switched, the terminal device cannot continue communication.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a communication control method for continuing communication between terminal devices connected to a base station device even under circumstances that cause trouble in communication. And it is providing the base station apparatus using it.

  One embodiment of the present invention is a base station apparatus. This device has one end connected to a network and the other end connected to a plurality of communication devices, and monitors a state of the network and a communication unit that performs communication between each of the plurality of communication devices and the network. Control that instructs the communication unit to switch from communication between each of the plurality of communication devices to communication between the plurality of communication devices based on the monitoring unit and the result of monitoring the state of the network A part. According to this apparatus, the communication unit may notify each of the plurality of communication apparatuses that the communication has been switched to the communication between the plurality of communication apparatuses.

  Even when switching to communication between multiple communication devices according to the status of the network, the above devices notify the communication device that it has switched, so the communication device recognizes that it has switched and Communication can be continued.

  The monitoring unit monitors the occurrence of a network failure as the state of the network, and the control unit, with respect to the communication unit, detects each occurrence of a network failure when the monitoring unit detects the occurrence of a network failure. An instruction is given to switch from communication with the network to communication between the plurality of communication devices, and the communication unit indicates that the communication has been switched to communication between the plurality of communication devices, and causes the occurrence of a network failure to the plurality of communication devices. Each may be notified.

  “Network failure” indicates that the link of the network is disconnected, but further indicates that the communication function in the network is reduced, including the case where the throughput in the network is reduced.

The communication unit sets a broadcast channel for broadcasting predetermined information to each of the plurality of communication devices when the communication between each of the plurality of communication devices and the network is being performed. A plurality of communication devices may be notified of the fact that the channel has been switched to communication between the plurality of communication devices.
“Predetermined information” is information necessary for communication between the base station apparatus and the communication apparatus, and includes, for example, an identification number of the base station apparatus.

  The communication unit notifies each of the plurality of communication devices that the communication channel is switched to the communication between the plurality of communication devices using the notification channel, and then notifies the new information to each of the plurality of communication devices. A different broadcast channel may be further set. The information storage part which memorize | stores the information which should be alert | reported by a new alerting | reporting channel is further provided, and a communication part alert | reports the information memorize | stored using the new alerting | reporting channel to each of several communication apparatuses.

  The content of “new information” may be arbitrary, but includes information to be notified from a base station apparatus to a plurality of communication apparatuses and information to be notified from one of a plurality of communication apparatuses to the rest.

When the communication unit switches to communication between a plurality of communication devices, a detection unit that detects information related to a target to which the signal is transmitted from a signal received from a predetermined communication device, and the detected information transmits a signal When one of a plurality of communication devices is specified as a target to be transmitted, the received signal is transmitted to the specified communication device, and the detected information specifies a plurality of communication devices as a target to which the signal is to be transmitted. A transmission unit that transmits the received signal to each of the plurality of communication devices. The detection unit detects the value of the flag included in the received signal as information on the target to which the signal is to be transmitted, and transmits the value of the flag included in the received signal to the designated communication device, or Any of transmissions to a plurality of communication devices may be supported.
“Information related to a target to be transmitted” is information necessary for transmitting a signal, such as an address of a communication device to be transmitted and a transmission method.

  One embodiment of the present invention is a communication control method. The method includes the steps of executing communication between each of the plurality of communication devices and the network, monitoring the state of the network, and each of the plurality of communication devices based on the result of monitoring the state of the network. A step of switching from communication with a network to communication between a plurality of communication devices, and a step of notifying each of the plurality of communication devices of switching to communication between the plurality of communication devices.

  The monitoring step monitors the occurrence of a network failure as a network state, and the switching step is performed between each of the plurality of communication devices and the network when the occurrence of the network failure is detected in the monitoring step. The step of instructing and notifying the communication to switch to communication between a plurality of communication devices notifies each of the plurality of communication devices of the occurrence of a network failure on the assumption that the communication has been switched to communication between the plurality of communication devices. May be.

  The step of executing communication sets a broadcast channel for broadcasting predetermined information to each of the plurality of communication devices when communication between each of the plurality of communication devices and the network is being performed. The notifying step may notify each of the plurality of communication devices that the communication channel has been switched to the communication using the notification channel.

  The step of communicating is to notify each of the plurality of communication devices of new information after each of the plurality of communication devices is notified that the communication channel has been switched to communication between the plurality of communication devices. The new broadcast channel may be further set. The method may further include a step of storing information to be broadcast on the new broadcast channel, and the step of communicating may broadcast the information stored using the new broadcast channel to each of the plurality of communication devices.

  In the communication step, when switching to communication between a plurality of communication devices, a step of detecting information related to a target to which the signal is transmitted from a signal received from a predetermined communication device, and the detected information transmits a signal. When one of a plurality of communication devices is specified as a target to be transmitted, the received signal is transmitted to the specified communication device, and the detected information specifies a plurality of communication devices as a target to which the signal is to be transmitted. And transmitting the received signals to a plurality of communication devices.

  The step of detecting detects the value of the flag included in the received signal as information on the object to which the signal is to be transmitted, and transmits the value of the flag included in the received signal to the designated communication device, Or you may respond to either of the transmission with respect to a some communication apparatus.

  It should be noted that any combination of the above-described constituent elements and a conversion of the expression of the present invention between a method, an apparatus, a system, a recording medium, a computer program, etc. are also effective as an aspect of the present invention.

  According to the present invention, communication between terminal devices connected to a base station device can be continued even under a situation that hinders communication.

  Before describing the present invention in detail, an outline will be described. An embodiment of the present invention relates to a wireless communication system in which a plurality of terminal devices communicate with a base station device. Here, although an FWA system is targeted as a wireless communication system, the FWA system is also referred to as a WLL (Wireless Local Loop) system. The terminal device according to the present embodiment is connected to the network via the base station device. Furthermore, the terminal device executes telephone communication such as an IP phone with a predetermined communication device connected to the network, or executes data communication if the network is the Internet.

  In these cases, the network generally includes an exchange or a router (hereinafter collectively referred to simply as a “router”), and data transmitted from a communication device or the Internet is accurately received by the terminal device by the router. Control is performed so that the data transmitted from the terminal device is accurately received by the communication device or the Internet. At that time, the base station device relays data communicated between the router and the terminal device. In addition, when the communication protocol in the wireless communication system is IP, the base station apparatus may convert a global IP address used in the network and a private IP address used in the terminal apparatus.

  The base station apparatus according to the present embodiment monitors the state of the network to which the base station apparatus is connected, particularly the state of the link with the router. When the link is disconnected, communication between the router and the terminal device is usually impossible, and the terminal device cannot execute telephone communication or data communication. On the other hand, there are cases where telephone communication or data communication is executed between two terminal devices connected to one base station device. In particular, the situation described above is assumed when telephone communication such as IP telephone is being executed. Furthermore, when the wireless communication system is not a system based on movement of a terminal device such as a mobile communication system, but is a system based on use at a fixed location such as an FWA system, the terminal device is Continue to be connected to the base station device. Therefore, it is desirable that telephone communication be continued between two terminal devices connected to one base station device regardless of before or after the link is disconnected.

  When the base station apparatus detects link disconnection, the routing controlled by the router enables the communication between the terminal apparatuses connected to the base station apparatus (hereinafter referred to as “intra-area routing”). Switch to. Further, the base station apparatus notifies the terminal apparatus that the routing has been switched. Upon receiving the notification, the terminal device transmits data to the terminal device connected to the base station device, and if there is data to be notified to all the terminal devices connected to the base station device, Data to be transmitted is transmitted to the base station apparatus. The base station apparatus broadcasts the data to all terminal apparatuses.

  FIG. 1 shows a configuration of a communication system 100 according to an embodiment of the present invention. The communication system 100 includes a first terminal device 10 a, a second terminal device 10 b, an M-th terminal device 10 m, a base station device 12, a network 14, and a communication device 16 that are collectively referred to as the terminal device 10. Further, the base station apparatus 12 includes a first antenna 30a, an Nth antenna 30n, which are collectively referred to as an antenna 30, a routing control unit 20, an IF unit 22, a failure detection unit 24, a storage unit 26, and a device control unit 28. In addition, the wireless side digital signal 200, the network side digital signal 202, the storage unit signal 204, the detection signal 206, and the wireless side analog signal 208 are included as signals.

  The terminal device 10 is connected to the base station device 12 and communicates with another terminal device 10 connected to the same base station device 12 or connected to another base station device 12 not shown via the network 14. It communicates with another terminal device 10 or communicates with the communication device 16. The communication device 16 is connected to the network 14 and communicates with any of the terminal devices 10 as described above.

  The antenna 30 transmits and receives radio signals to and from the terminal device 10. Although the number of antennas 30 may be one, here, it is assumed that N antennas 30 are provided and each has a different directivity.

  N wireless communication units 18 are provided corresponding to the N antennas 30, and each connects the terminal device 10. Each of the plurality of wireless communication units 18 is assumed to multiplex the terminal device 10 by CDMA or TDMA. Here, a signal between the radio communication unit 18 and the antenna 30 is a radio side analog signal 208, and a signal between the radio communication unit 18 and a routing control unit 20 described later is a radio side digital signal 200. Note that processing in the upper layer of the communication protocol for data transmitted and received by the wireless communication unit 18 is performed by the routing control unit 20.

  The routing control unit 20 controls communication so that the terminal device 10 and the communication device 16 can communicate via the network 14. Here, processing relating to the address of the terminal device 10 and the address of the communication device 16 is performed. For example, when the communication protocol used in the communication system 100 is an IP protocol, a router (not shown) provided in the network 14 assigns a global IP address to one of the terminal devices 10 to be communicated. The routing control unit 20 controls the terminal device 10 corresponding to the assigned global IP address so that the wireless communication unit 18 corresponding to the terminal device 10 transmits and receives data. When a private IP address is assigned to the terminal device 10 without using the global IP address as it is, the routing control unit 20 performs address conversion between the global IP address and the private IP address. The above is the operation of the routing control unit 20 in the normal state (hereinafter referred to as “normal operation” or “normal operation”), but other operations will be described later.

The IF unit 22 is an interface between the routing control unit 20 and the network 14. The IF unit 22 is not limited to a physical interface, and may be an interface corresponding to an upper layer of a communication protocol. Here, data transmitted between the routing control unit 20 and the network 14 is referred to as a network-side digital signal 202.
The storage unit 26 stores information to be used for processing related to the address in the routing control unit 20. Details of the information stored in the storage unit 26 will be described later. The device control unit 28 controls the timing of the base station device 12 and the like.

  The failure detection unit 24 monitors the state of the network 14, for example, the connection with a router (not shown) connected to the network 14. In other words, the failure detection unit 24 monitors the connection with the router and detects the occurrence of a failure in the network 14 that has been disconnected from the router. The state of the network 14 may be other than the connection with the router. For example, the data throughput in the network 14 may be measured. In that case, when the measured throughput becomes lower than a predetermined threshold value, a failure of the network 14 occurs. Here, a signal transmitted from the failure detection unit 24 when the failure detection unit 24 detects the occurrence of a failure in the network 14 is referred to as a detection signal 206.

  When the detection signal 206 from the failure detection unit 24 is input to the routing control unit 20, that is, when the occurrence of a failure in the network 14 is detected, the routing control unit 20 responds to the terminal device 10 in the wireless communication unit 18. Switch processing related to addresses. As described above, the routing control unit 20 controls communication so that the terminal device 10 and the network 14 can communicate until the detection signal 206 is input. However, in response to the input of the detection signal 206, the routing control unit 20 switches to communication control that allows communication between the terminal apparatuses 10, that is, as described above, to intra-area routing. Furthermore, the routing control unit 20 and the wireless communication unit 18 notify the terminal device 10 that switching to intra-area routing has been performed. Note that it is only necessary to notify the terminal device 10 that the switching has been performed, and the signal transmitted from the wireless communication unit 18 to the terminal device 10 may be a signal indicating the occurrence of a network 14 failure.

  This configuration can be realized in terms of hardware by a CPU, memory, or other LSI of an arbitrary computer, and in terms of software, it is realized by a program having a reservation management function loaded in memory. The functional block realized by those cooperation is drawn. Accordingly, those skilled in the art will understand that these functional blocks can be realized in various forms by hardware only, software only, or a combination thereof.

  FIG. 2 shows channel transitions in the communication system 100. Here, only radio channels necessary for the description of the present embodiment will be described. The base station apparatus 12 broadcasts a broadcast channel on the downlink (S10). The broadcast channel includes information regarding the base station apparatus 12, and the terminal apparatus 10 recognizes the presence of the connectable base station apparatus 12 by receiving the broadcast channel. The terminal device 10 that requests connection to the base station device 12, that is, the terminal device 10 that requests execution of voice communication or data communication, transmits a random access channel to the base station device 12 on the uplink (S12). The base station apparatus 12 that has received the random access channel from the terminal apparatus 10 confirms the existence of the terminal apparatus 10 that requests connection. However, since the random access channel is transmitted by a plurality of terminal apparatuses 10 that request connection to the base station apparatus 12, the timings at which these plurality of terminal apparatuses 10 transmit may be simultaneous, and in such a case However, the base station apparatus 12 does not receive it correctly. In such a case, the terminal device 10 transmits the random access channel again.

  When the base station apparatus 12 receives the random access channel from the terminal apparatus 10 and determines the connection of the terminal apparatus 10, that is, when it determines data communication or voice communication with the terminal apparatus 10, it acquires and displays on the downlink. The channel is transmitted (S14). The terminal device 10 that has received the acquired display channel transmits and receives a predetermined control signal for performing voice communication or data communication with the base station device 12, but the description thereof is omitted here. When the terminal apparatus 10 performs data communication with the base station apparatus 12, the base station apparatus 12 transmits a downlink data channel to the terminal apparatus 10 (S16). The data channel corresponds to the aforementioned burst signal, and is not transmitted periodically, but is transmitted as necessary, such as generation of data to be transmitted. On the other hand, when the terminal apparatus 10 performs voice communication with the base station apparatus 12, the base station apparatus 12 allocates a call channel for uplink and downlink to the terminal apparatus 10 (S16). The speech channel periodically transmits voice data between the terminal device 10 and the base station device 12.

  In the present embodiment, the base station apparatus 12 notifies the terminal apparatus 10 that the switching to the above-described intra-area routing is performed using the broadcast channel. Since this broadcast channel is received by the terminal device 10 even when the terminal device 10 and the network 14 are in communication, the broadcast channel is received by the terminal device 10 as long as the broadcast channel is switched to intra-area routing. . Further, although not shown in FIG. 2, the base station device 12 notifies the terminal device 10 that the intra-area routing has been switched using the broadcast channel, and then a new broadcast channel (hereinafter referred to as “broadcast channel”) that is different from the broadcast channel. , “Emergency notification channel”).

  FIG. 3 shows a configuration of the first wireless communication unit 18a. The first wireless communication unit 18a includes a switching unit 40, a transmission RF unit 42, a modulation unit 44, a reception RF unit 46, a demodulation unit 48, and a baseband processing unit 50.

  The switching unit 40 changes signal input / output depending on whether the first wireless communication unit 18a performs transmission processing or reception processing. When the first wireless communication unit 18a performs reception processing, the switching unit 40 outputs the input wireless-side analog signal 208 to the reception RF unit 46, and when the first wireless communication unit 18a performs transmission processing, The switching unit 40 outputs the signal output from the transmission RF unit 42 as the wireless-side analog signal 208.

  The reception RF unit 46 converts the frequency of the radio side analog signal 208 from a radio frequency to a frequency processed by the demodulation unit 48, for example, baseband, and performs AD conversion on the signal converted to baseband, Convert to digital signal. In addition, the reception RF unit 46 includes a low noise amplifier and amplifies the radio side analog signal 208.

  The demodulator 48 demodulates the signal input from the reception RF unit 46. Here, it is assumed that any one of QPSK (Quadrature Phase Shift Keying), 16QAM (Quadrature Amplitude Modulation), and 64QAM is used as the modulation method. The modulation unit 44 modulates a signal that is input from the baseband processing unit 50 and to be transmitted. The transmission RF unit 42 performs DA conversion on the signal input from the modulation unit 44 and further converts the signal to a radio frequency. In addition, the transmission RF unit 42 includes a high output amplifier, and amplifies a signal to be output to the switching unit 40.

  The baseband processing unit 50 performs predetermined processing on the baseband signal before modulation and the baseband signal after demodulation. For example, error correction encoding is performed on the baseband signal before modulation, and error correction decoding is performed on the demodulated baseband signal. Further, processing corresponding to a higher layer in the communication protocol, for example, a MAC layer or an RLC (Radio Link Control) layer is also performed.

  FIG. 4 shows the configuration of the routing control unit 20. The routing control unit 20 includes a first switching unit 60, a network routing unit 62, an in-area routing unit 64, and a second switching unit 66. The intra-area routing unit 64 includes a detection unit 68 and a transmission destination determination unit 70.

  The first switching unit 60 and the second switching unit 66 select one of the network routing unit 62 and the in-area routing unit 64 according to the detection signal 206. When the fact that switching to intra-area routing has not been input by the detection signal 206, the first switching unit 60 and the second switching unit 66 switch signals so that the network routing unit 62 operates. On the other hand, when the fact that switching to the intra-area routing is input by the detection signal 206, the first switching unit 60 and the second switching unit 66 switch the signals so that the intra-area routing unit 64 operates.

  The network routing unit 62 controls communication so that the terminal device 10 and the communication device 16 can communicate with each other via the network 14 in the normal operation. In this case, the radio side digital signal 200 and the network side digital signal 202 are set as signals to be processed. Since the operation of the network routing unit 62 has already been described, detailed description is omitted here, but the network routing unit 62 executes communication control based on the information stored in the storage unit 26 of FIG. FIG. 5 shows a data structure of information related to a routing target device stored in the storage unit 26. “Address” indicates an address assigned to the first terminal device 10a, the communication device 16, and the like of FIG. Here, for the sake of simplicity of explanation, addresses are indicated by “A”, “B”, “C”, “X”, etc., but these are, for example, IP addresses “192.168.0.1” and the like. Equivalent to.

  The “device name” is a name of a device to be processed, and is indicated here as “first terminal device”, “second terminal device”, “third terminal device”, and “communication device”. These correspond to identification numbers that can specify each device such as a MAC address, for example. The “connection destination” is a name of a member that inputs / outputs data corresponding to the “device name”. For example, data for the first terminal device 10a is input / output to / from the first wireless communication unit 18a, data for the second terminal device 10b is input / output to / from the first wireless communication unit 18a, and data for the third terminal device 10c (not shown) is input. Input / output to / from the second wireless communication unit 18 b and input / output data for the communication device 16 to the IF unit 22. These pieces of information are not only unilaterally read from the storage unit 26 by the network routing unit 62 but also written from the storage unit 26 according to the information change. The network routing unit 62 uses the storage unit signal 204 to transmit such information to and from the storage unit 26.

  Returning to FIG. The intra-area routing unit 64 performs intra-area routing. As described above, intra-area routing controls communication between a plurality of terminal apparatuses 10 connected to the base station apparatus 12 of FIG. 1, so that the information stored in the storage unit 26 shown in FIG. Among these, the terminal device 10 whose “connection destination” is the wireless communication unit 18 is targeted. The intra-area routing unit 64 and the wireless communication unit 18 (not shown) perform intra-area routing when switching to intra-area routing as described above, that is, when switching from the operation of the network routing unit 62 to the operation of the intra-area routing unit 64. Send a signal to the effect of switching.

  FIGS. 6A to 6C show the data structure of the broadcast channel transmitted by the base station apparatus 12. FIG. 6A shows a data structure of a broadcast channel transmitted when the network routing unit 62 is operating, that is, in a normal case. “System information 1” to “system information K” are predetermined information, and include, for example, the identification number of the base station apparatus 12, the identification number of the antenna 30, and the information of the surrounding base station apparatuses 12. Here, the last added information is an emergency notification flag, and the case of “0” as shown in the figure corresponds to the case where the network routing unit 62 is operating. FIG. 6B shows a data structure of a broadcast channel transmitted when the intra-area routing unit 64 is operating, that is, when operating in intra-area routing.

  In FIG. 6B, unlike FIG. 6A, the emergency notification flag is “1”, and “emergency notification information” is added corresponding to “1” of the emergency notification flag. Here, “1” of the emergency notification flag corresponds to a signal indicating that the above-described intra-area routing has been switched. That is, the terminal device 10 receives the broadcast channel and checks the value of the “emergency broadcast flag” included in the received broadcast channel. If the “emergency notification flag” is “0”, the terminal device 10 recognizes the normal operation, and if the “emergency notification flag” is “1”, the terminal device 10 recognizes the intra-area routing operation.

  FIG. 6C shows the data structure of the “emergency notification information” shown in FIG. The “system information type” is information indicating emergency notification information, and is used to distinguish it from information used other than emergency notification information. The “emergency notification channel number” is information related to the emergency notification channel when the base station apparatus 12 sets the emergency notification channel as described above after transmitting the “emergency notification information”, for example, the emergency notification channel number. This is a signal for notifying the terminal device 10 of the identification number, frequency, and spreading code. “Modulation method” and “data length” indicate the modulation method and data length of “emergency notification additional information” arranged in the subsequent stage. “Emergency notification additional information” is information to be notified from the base station apparatus 12 to the terminal apparatus 10, and when the terminal apparatus 10 receives the information, for example, the information is displayed on the display apparatus.

  FIGS. 7A to 7B show displays on the terminal device 10 that has received the “emergency notification additional information”. Information indicating that the router is disconnected as shown in FIG. 7A may be included in the “emergency notification additional information”, and the terminal device 10 may display the information as shown in FIG. Moreover, the information regarding an evacuation place like FIG.7 (b) may be included in "emergency alert additional information", and the terminal device 10 may display as shown in FIG.7 (b). It is assumed that these pieces of information are stored in advance in the storage unit 26 of FIG.

  Returning to FIG. The intra-area routing unit 64 uses the detection unit 68 and the transmission destination determination unit 70 to execute intra-area routing. When the intra-area routing unit 64 is performing intra-area routing, the detection unit 68 detects information related to a target to which the signal is to be transmitted from a signal received from a predetermined terminal device 10. Here, the information regarding the target to which the signal is to be transmitted corresponds to the transmission destination of the signal. FIG. 8 shows a data structure of a signal received by the base station apparatus 12. The “broadcast flag” indicates whether all of the terminal devices 10 to which the base station device 12 is connected are notified or transmitted to a predetermined terminal device 10.

  Returning to FIG. The transmission destination determination unit 70 determines the transmission destination of the signal based on the broadcast flag detected by the detection unit 68. That is, if the “broadcast flag” in FIG. 8 is “1”, the base station device 12 has connected “data” transmitted from the terminal device 10 of “source address” regardless of the “destination address”. All terminal devices 10 are notified. On the other hand, if the “broadcast flag” is “0”, the “data” transmitted from the terminal device 10 of “source address” is notified to the terminal device 10 corresponding to the “destination address”. 7A to 7B, the data to be included in the “emergency notification additional information” has been described. However, the information corresponding to FIGS. 7A to 7B is stored in the storage unit 26 in FIG. And may be included in the “data” of FIG. By defining such a signal, predetermined information can be shared among a plurality of terminal apparatuses 10 connected to one base station apparatus 12.

  FIG. 9 is a flowchart showing a communication procedure of the base station apparatus 12. In a state where the wireless communication unit 18 is connected to the terminal device 10 and the IF unit 22 is connected to the network 14 and is communicating with each other, the failure detection unit 24 monitors the link with the network 14 (S20). ). If the link detection is detected by the failure detection unit 24 (Y in S22), the base station apparatus 12 notifies the emergency notification information through the notification channel (S24), and further sets the emergency notification channel (S26). ). The routing control unit 20 switches the communication control to intra-area routing (S28). Note that the operation of step 28 may be arranged before the operation of step 24. In this case, after switching to intra-area routing by the routing control unit 20, the emergency notification information is notified through the notification channel.

  The wireless communication unit 18 receives data from the terminal device 10 (S30). The transmission destination determination unit 70 identifies the transmission destination of data (S32). If the transmission destination is within the area (Y in S34), that is, if it is any of the terminal devices 10 connected to the base station device 12, and if the transmission destination is all the terminal devices 10 in the area (Y in S36), the base station apparatus 12 transmits the received information using the emergency notification channel (S38). On the other hand, if the destination is not all the terminal devices 10 in the area (N in S36), if there is an empty call channel (Y in S42), the base station device 12 transmits the received information using the call channel. (S44). If the transmission destination is not in the area (N in S34) or there is no free call channel (N in S42), the base station apparatus 12 transmits a message indicating that transmission is impossible to the terminal apparatus 10 that is the transmission source (S46). ). If the link disconnection is not detected based on the link state monitored by the failure detection unit 24 (N in S22), the base station apparatus 12 performs a normal operation (S40).

  FIG. 10 is a flowchart illustrating a communication procedure of the terminal device 10. The terminal device 10 receives the broadcast channel transmitted from the base station device 12 (S50). If the emergency notification flag included in the notification channel is ON, that is, “1” (Y in S52), the terminal device 10 sets a spreading code or the like so that the emergency notification channel can be received (S54). Further, based on the information included in the broadcast channel, an urgent message is displayed as shown in FIGS. 7A to 7B (S56). When the terminal device 10 does not transmit data (N in S58) but receives data (S60), if the data is received through the emergency notification channel (Y in S62), the terminal device 10 Broadcast channel data is processed (S64). On the other hand, if the data is not received through the emergency notification channel (N in S62) and is not information that cannot be transmitted (N in S70), the terminal device 10 processes the data of the call channel (S72). If it is information that transmission is impossible (Y in S70), the terminal device 10 stops the transmission operation (S74).

  When the terminal device 10 transmits data (Y in S58), the data is transmitted through the call channel (S68). Note that if the emergency notification flag included in the notification channel is not ON, that is, “0” (N in S52), the terminal apparatus 10 performs a normal operation on the base station apparatus 12.

  The operation of the communication system 100 configured as above will be described with reference to FIG. FIG. 11 is a sequence diagram illustrating a communication procedure of the communication system 100. Here, it is assumed that the first terminal apparatus 10a and the second terminal apparatus 10b connected to one base station apparatus 12 are communicating. Further, a router connected to the network 14 will be described as the network 14. When transmitting data from the first terminal apparatus 10a to the second terminal apparatus 10b, the first terminal apparatus 10a transmits data to the base station apparatus 12 (S80), and via the network 14 (S82, S84), the base station The device 12 transmits data to the second terminal device 10b (S86). In addition, when transmitting data from the 2nd terminal device 10b to the 1st terminal device 10a, data are transmitted in the order opposite to the above. If the base station device 12 detects a failure with the network 14 (S88), the base station device 12 switches to intra-area routing (S90).

  The base station apparatus 12 transmits information indicating that switching to intra-area routing is performed to the first terminal apparatus 10a (S92), and further transmits to the second terminal apparatus 10b (S94). Although Step 92 and Step 94 are described as separate steps, actually, they are transmitted using the same broadcast channel. If data to be transmitted is generated (S96), the first terminal apparatus 10a transmits the data to the base station apparatus 12 (S98). The base station apparatus 12 confirms that the transmission destination of the received data is the second terminal apparatus 10b, and transmits the data to the second terminal apparatus 10b (S100). The second terminal device 10b executes reception processing (S102).

  According to the embodiment of the present invention, when the occurrence of a network failure is detected in a state where the terminal device is connected to one end and the network is connected to the other end, the terminal device is notified of the occurrence of the failure. Thus, the terminal device can recognize the switching and can reliably execute the communication between the terminal devices. Further, by detecting the occurrence of a network failure, it is possible to estimate the occurrence of a disaster and notify the terminal device. In addition, since the broadcast channel used during communication is used to notify the occurrence of a network failure, notification is reliably performed while suppressing an increase in the processing amount of the terminal device. In addition, since a new broadcast channel to be broadcast to terminal devices connected to one base station device is set, predetermined information can be shared between the terminal devices. In addition, since the signal to be notified can be detected based on the value of the flag included in the signal during intra-area routing, the process becomes simple. In addition, for the user, communication with a predetermined terminal device can be continued even if a failure occurs in the network. In addition, for a communication carrier, a predetermined communication service can be provided even if a failure occurs in the network.

  The present invention has been described based on the embodiments. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to combinations of the respective constituent elements and processing processes, and such modifications are also within the scope of the present invention. is there.

  In the embodiment of the present invention, the terminal device 10 is named a terminal device because it corresponds to a terminal device in communication with the base station device 12. However, the present invention is not limited to this. For example, the terminal device 10 connects another communication device using a communication method different from that between the base station device 12 and the terminal device 10, and data is transmitted between the communication device and the base station device 12. May have a function of relaying. That is, the terminal device 10 may correspond to a base station device in relation to another communication device. The communication method between the terminal device 10 and another communication device is not limited to wireless communication, and may be wired communication. According to this modification, the present invention can be applied to various communication forms. That is, it only needs to be connected to the base station apparatus 12.

  In the embodiment of the present invention, the failure detection unit 24 monitors the state of the network 14. However, the present invention is not limited to this. For example, the status of energization to the base station device 12 is also monitored, and the presence or absence of a disaster is detected according to the state of the network 14 and the status of energization to the base station device 12 and output to the routing control unit 20. May be. In that case, the base station apparatus 12 notifies the terminal apparatus 10 of the occurrence of a disaster. It is assumed that the base station apparatus 12 includes a battery or the like. According to this modification, it is possible to distinguish a simple failure of the network 14 from a disaster. That is, it is only necessary to identify the cause of the failure that has occurred in the network 14.

  In the embodiment of the present invention, the detection unit 68 transmits data to one terminal device 10 based on a “broadcast flag” included in the data, or notifies a plurality of terminal devices 10. It was determined. However, the present invention is not limited to this. For example, a “broadcast flag” may not be provided in the data, and a broadcast address may be defined in advance for the destination address. In that case, the detection unit 68 determines whether to transmit the data to one terminal device 10 or to notify the plurality of terminal devices 10 based on the address of the transmission destination included in the data. According to this modification, the broadcast flag is not necessary. That is, it is only necessary to distinguish whether data is transmitted to one terminal device 10 or notified to a plurality of terminal devices 10.

It is a figure which shows the structure of the communication system which concerns on the Example of this invention. It is a figure which shows the transition of the channel in the communication system of FIG. It is a figure which shows the structure of the 1st radio | wireless communication part of FIG. It is a figure which shows the structure of the routing control part of FIG. It is a figure which shows the data structure of the information regarding the apparatus of routing object memorize | stored in the memory | storage part of FIG. FIGS. 6A to 6C are diagrams illustrating data structures of broadcast channels transmitted by the base station apparatus of FIG. FIGS. 7A and 7B are views showing display on the terminal device of FIG. It is a figure which shows the data structure of the signal which the base station apparatus of FIG. 1 receives. It is a flowchart which shows the communication procedure of the base station apparatus of FIG. It is a flowchart which shows the communication procedure of the terminal device of FIG. It is a sequence diagram which shows the communication procedure of the communication system of FIG.

Explanation of symbols

  10 terminal devices, 12 base station devices, 14 networks, 16 communication devices, 18 wireless communication units, 20 routing control units, 22 IF units, 24 fault detection units, 26 storage units, 28 device control units, 30 antennas, 40 switching units 42 transmitting RF unit, 44 modulating unit, 46 receiving RF unit, 48 demodulating unit, 50 baseband processing unit, 60 first switching unit, 62 network routing unit, 64 intra-area routing unit, 66 second switching unit, 68 detecting unit, 70 transmission destination determining unit, 100 communication system, 200 radio side digital signal, 202 network side digital signal, 204 storage unit signal, 206 detection signal, 208 radio side analog signal.

Claims (8)

One end is connected to a network, the other end is connected to a plurality of communication devices, and a communication unit that performs communication between each of the plurality of communication devices and the network,
A monitoring unit for monitoring the state of the network;
Based on the result of monitoring the state of the network, the communication unit is instructed to switch from communication between each of the plurality of communication devices to communication between the plurality of communication devices. A control unit,
The base station apparatus, wherein the communication unit notifies each of the plurality of communication apparatuses that the communication has been switched to communication between the plurality of communication apparatuses. The monitoring unit monitors the occurrence of a network failure as the state of the network,
When the occurrence of a failure in the network is detected in the monitoring unit, the control unit communicates the communication with the communication unit from communication between each of the plurality of communication devices and the network. Instructed to switch to communication between devices,
2. The base station apparatus according to claim 1, wherein the communication unit notifies the plurality of communication apparatuses of occurrence of a failure of the network as switching to communication between the plurality of communication apparatuses.   The communication unit sets a broadcast channel for broadcasting predetermined information to each of the plurality of communication devices when performing communication between each of the plurality of communication devices and the network. The base station apparatus according to claim 1, wherein the base station apparatus notifies the plurality of communication apparatuses that the communication channel has been switched to communication using the broadcast channel.   The communication unit notifies the plurality of communication devices that the communication channel is switched to communication between the plurality of communication devices using the broadcast channel, and then sends new information to each of the plurality of communication devices. The base station apparatus according to claim 3, further comprising setting a new broadcast channel for broadcasting. An information storage unit for storing information to be broadcast on the new broadcast channel;
The base station apparatus according to claim 4, wherein the communication unit broadcasts the stored information to each of the plurality of communication apparatuses using the new broadcast channel. The communication unit is
When switching to communication between the plurality of communication devices, from a signal received from a predetermined communication device, a detection unit that detects information on a target to which the signal is to be transmitted;
When the detected information designates one of the plurality of communication devices as a target to which a signal is to be transmitted, the received signal is transmitted to the designated communication device, and the detected information transmits a signal. When the plurality of communication devices are designated as targets to be transmitted, a transmission unit that transmits the received signals to the plurality of communication devices,
The base station apparatus according to claim 1, further comprising:   The detection unit detects a flag value included in the received signal as information on a target to which the signal is to be transmitted, and the flag value included in the received signal is the specified communication. The base station apparatus according to claim 6, wherein the base station apparatus corresponds to either transmission to an apparatus or transmission to the plurality of communication apparatuses. Performing communication between each of the plurality of communication devices and the network;
Monitoring the status of the network;
Based on the result of monitoring the state of the network, switching from communication between each of the plurality of communication devices and the network to communication between the plurality of communication devices;
Notifying each of the plurality of communication devices that the communication has been switched between the plurality of communication devices;
A communication control method comprising:

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