JP5365771B2 - Voice IP phone - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a speech IP telephone device that provides speech communication of high quality without altering an existent network. <P>SOLUTION: The speech IP telephone device includes an input/output device 10 including a display unit and an operation unit, a LAN interface 1 for communication with an opposite device through an IP network such as a local LAN and a home LAN, a codec unit 2 which encodes and compresses a voice signal to be transmitted, a decoding unit 3 which decodes received voice data, a communication monitor unit 4 which monitors communication through the LAN interface, a communication system selection unit 5 which selects a suitable communication system according to a monitoring result of a communication state, and a communication unit 6 which performs communication by the selected communication system. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a voice IP telephone apparatus, and more particularly to a voice IP telephone apparatus that adaptively switches a communication method according to the state of an IP network.

  In conventional telephone communication lines (analog, ISDN, etc.), the bandwidth used is secured, so the same communication control is fixedly performed regardless of the bandwidth usage. On the other hand, since it is difficult to secure the bandwidth used for voice communication using the IP network, the communication method can be adapted according to the state of the IP network, especially the bandwidth used, if sufficient call quality is to be maintained. It is desirable to control.

In voice communication using an IP network, VPN (Virtual Private Network) and RSVP (Resource reSerVation Protocol: resource reservation) are used to detect the bandwidth used or to ensure sufficient call quality by securing the bandwidth used. Patent Document 1 discloses a technique that employs a protocol.
JP 2001-285354 A

  In order to secure the bandwidth by the above-mentioned VPN or RSVP, it is necessary to add a special router device or the like corresponding to VPN or RSVP to the network, and it is necessary to change the existing network and to pay a large cost.

  An object of the present invention is to solve the above-described problems of the prior art and to provide a voice IP telephone device that enables a high-quality voice call without changing an existing network.

In order to achieve the above object, the present invention is characterized in that the following measures are taken.
(1) a LAN interface that communicates with a partner device via a LAN connected to the IP network, a monitoring unit that monitors the state of the IP network, a communication method selection unit that selects a communication method according to the state of the IP network, The communication apparatus includes a communication unit that executes communication using the selected communication method, and a storage unit that stores a communication history in the communication .
(2) If the communication history selection means does not store the outgoing call control signal or the incoming call control signal retransmission history in the previous communication in the communication history, the encoding is performed when the state of the IP network deteriorates from a predetermined reference state. It is characterized by switching to a highly efficient codec communication method, or restricting communication, or switching the communication path from the IP network via the LAN interface to the PSTN via the PSTN interface.
(3) The communication method selection means stores the retransmission history of the outgoing call control signal or the incoming call control signal in the previous communication in the communication history, and if the predetermined time or more has not passed since the previous outgoing or incoming call, Regardless of the state of the IP network, switch to a codec communication method with high coding efficiency, or restrict communication, or switch the communication path from the IP network via the LAN interface to the PSTN via the PSTN interface .

According to the present invention, the following effects are achieved.
(1) Communication control that the voice IP telephone device monitors the state of the IP network itself and switches the codec method to a method with high coding efficiency or restricts communication when the bandwidth of the IP network is low As a result, a high-quality voice call is possible without changing the existing network.
(2) If the PSTN interface that communicates with the other device via the PSTN is further provided and the IP network bandwidth is reduced, the communication via the IP network is switched to the PSTN, so the IP network bandwidth is reduced. Will be able to ensure high-quality communication.
(3) Records of retransmission of outgoing call control signals and retransmission of incoming call control signals and refers to them at the time of next outgoing call or incoming call, and the occurrence of retransmission of outgoing call control signals and retransmission of incoming call control signals is expected. In such a case, the codec method can be switched to a method with high coding efficiency, communication control via IP network can be switched to PSTN, or communication can be controlled immediately. Is possible.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the best embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a functional block diagram showing the configuration of the main part of a voice IP telephone apparatus according to the present invention. Here, the configuration unnecessary for the description of the present invention is omitted.

  The voice IP telephone apparatus according to the present invention includes an input / output device 10 including a display unit such as a liquid crystal display and an LED indicator, and an operation unit such as a key switch and an on-hook / off-hook switch, and a local LAN or a home LAN. The LAN interface 1 for communicating with the partner device via the IP network, the codec unit 2 for encoding and compressing the audio signal to be transmitted, the decoding unit 3 for decoding the received audio data, and the communication via the LAN interface are monitored. A communication monitoring unit 4 that predicts the state of the IP network, a communication method selection unit 5 that selects an optimal communication method according to the monitoring result of the communication state, and communication that performs communication using the selected communication method. Part 6. The codec unit 2, the decoding unit 3, the communication monitoring unit 4, the communication method selection unit 5, and the communication unit 6 can be configured by software.

Next, each embodiment of the present invention will be described in detail with reference to a flowchart. FIG. 2 is a flowchart showing the operation of changing the codec system according to the state of the IP network according to the present invention (particularly, the transmission side) , and FIG. 3 is a sequence flow thereof. Here, the operation when making a call from IP telephone apparatus A to IP telephone apparatus B will be described mainly focusing on the operation of IP telephone apparatus A on the caller side.

  When a transmission operation is performed on the input / output device 10 of the IP telephone apparatus A, and this is detected in step S11, the number Ns of retransmissions of the outgoing call control signal managed by the communication monitoring unit 4 is reset in step S12. The In step S13, a transmission operation is executed by the communication unit 6, and a transmission message destined for the IP telephone apparatus B is transmitted via the LAN interface. At this time, the standard communication method is selected in the communication method selection unit 5, and in response to this, G711 is selected as the codec method in the codec unit 2.

  If a response packet is returned from IP telephone apparatus B of the communication partner and this is detected in step S14, the process proceeds to a predetermined session establishment procedure. On the other hand, if a time-out occurs before a response is detected, the process proceeds to step S15, and the number Ns of retransmissions of the outgoing call control signal is incremented. In step S16, the communication method selection unit 5 compares the number Ns of retransmissions of the outgoing call control signal with a reference value Nref1. Initially, since it is determined that the number of retransmissions Ns of the outgoing call control signal is smaller than the reference value Nref1, the process returns to step S13, and the outgoing call control signal is retransmitted from the communication unit 6. After step S14, the same processing as described above is repeated. If there is no response, the number Ns of retransmissions of the outgoing call control signal continues to be incremented in step S15.

  Thereafter, when Ns> Nref1 is determined in step S16, the process proceeds to step S17, and the codec change is instructed from the communication method selection unit 5 to the codec unit 2 via the communication unit 6. In step S18, the codec change is notified from the communication unit 6 to the input / output device 10, and a message notifying the codec change is displayed on the display unit of the input / output device 10. In step S19, the codec unit 2 changes the codec system from the current G711 to G729 having a higher compression rate in response to the codec change command. In step S20, IP telephone apparatus B is transmitted again using the changed codec method.

According to FIGS. 2 and 3 , when the shortage of the IP network is predicted, the codec method is switched to a method with higher encoding efficiency, so that a call with a smaller bandwidth is possible.

FIG. 4 is a flowchart showing the operation of communication restriction (especially the transmission side) according to the state of the IP network in the present invention, and FIG. 5 is a sequence flow thereof. Here again, the operation when making a call from IP telephone apparatus A to IP telephone apparatus B will be described mainly focusing on the operation of IP telephone apparatus A on the caller side.

  When a call operation is performed on the input / output device 10 of the IP telephone apparatus A and this is detected in step S21, the number Ns of retransmissions of the outgoing call control signal managed by the communication monitoring unit 4 is reset in step S22. The In step S23, the call operation is executed by the communication unit 6, and a call message destined for the IP telephone apparatus B is transmitted via the LAN interface.

  If a response packet is returned from IP telephone apparatus B of the communication partner and this is detected in step S24, the process proceeds to a predetermined session establishment procedure. On the other hand, if a time-out occurs before a response is detected, the process proceeds to step S25, and the number Ns of retransmissions of the outgoing call control signal is incremented. In step S26, the communication method selection unit 5 compares the number Ns of retransmissions of the outgoing call control signal with a reference value Nref2. Initially, since it is determined that the number of retransmissions Ns of the outgoing call control signal is smaller than the reference value Nref2, the process returns to step S23, and the outgoing call control signal is retransmitted from the communication unit 6. In step S24 and subsequent steps, the same processing as described above is repeated. If there is no response, the number Ns of retransmissions of the outgoing call control signal continues to be incremented in step S25.

  Thereafter, when it is determined in step S26 that Ns> Nref2, the process proceeds to step S27, where the communication method selection unit 5 instructs the communication unit 6 to restrict outgoing calls. In step S <b> 28, the call restriction is notified from the communication unit 6 to the input / output device 10, and a message notifying the call restriction is displayed on the display unit of the input / output device 10. In step S29, the communication unit 6 performs a call restriction process in response to the call restriction, thereby restricting the call.

According to FIGS. 4 and 5 , when a shortage of bandwidth in the IP network is predicted, a further shortage of bandwidth can be prevented beforehand by restricting communication, so it is possible to prevent a reduction in call quality in an established session. It becomes like this.

FIG. 6 is a flowchart showing the operation of changing the codec system according to the state of the IP network according to the present invention (particularly the incoming side) , and FIG. 7 is a sequence flow thereof. Here, the operation when IP telephone apparatus A receives a call from IP telephone apparatus B will be described mainly focusing on the operation of IP telephone apparatus A on the receiving side.

  If an incoming call is detected by the communication unit 6 in step S31, the number of retransmissions Nr of the incoming call control signal managed by the communication monitoring unit 4 is reset in step S32. In step S33, when a response due to off-hook or the like is detected, in step S34, the apparatus stands by in preparation for session establishment.

  Thereafter, when retransmission of the incoming call control signal is detected in step S35, the process proceeds to step S36, and the number of retransmissions Nr of the incoming call control signal is incremented. In step S37, the communication method selection unit 5 compares the number Nr of retransmissions of the incoming call control signal with a reference value Nref3. Initially, since it is determined that the number of retransmissions Nr of the incoming call control signal is smaller than the reference value Nref3, the process returns to step S33.

  Thereafter, every time the retransmission of the incoming call control signal is detected in step S35, the number of retransmissions Nr of the incoming call control signal is continuously incremented in step S36. If Nr> Nref3 is determined in step S37, the process proceeds to step S38. In step S <b> 38, the codec change is instructed from the communication method selection unit 5 to the codec unit 2 through the communication unit 6. In step S39, the codec change is notified from the communication unit 6 to the input / output device 10, and a message notifying the codec change is displayed on the display unit of the input / output device 10. In step S40, the codec unit 2 changes the codec method from the current G711 to G729 having a higher compression rate in response to the codec change command. In step S41, the changed codec system is notified to IP telephone apparatus B, and in IP telephone apparatus B, the codec system is similarly changed.

According to FIGS. 6 and 7 , when the shortage of the IP network bandwidth is predicted, the codec method is switched to a method with higher encoding efficiency, so that a call with a smaller bandwidth is possible.

FIG. 8 is a flowchart showing the operation of communication restriction (especially the incoming side) according to the state of the IP network in the present invention, and FIG. 9 is a sequence flow thereof. Here, the operation when IP telephone apparatus A receives a call from IP telephone apparatus B will be described mainly focusing on the operation of IP telephone apparatus A on the receiving side.

  When an incoming call is detected by the communication unit 6 in step S51, the number of retransmissions Nr of the incoming call control signal managed by the communication monitoring unit 4 is reset in step S52. In step S53, when a response due to off-hook or the like is detected, in step S54, the apparatus stands by in preparation for session establishment.

  Thereafter, when retransmission of the incoming call control signal is detected in step S55, the process proceeds to step S56, where the number of retransmissions Nr of the incoming call control signal is incremented. In step S57, the communication method selection unit 5 compares the number Nr of retransmissions of the incoming call control signal with a reference value Nref4. Initially, since it is determined that the number Nr of retransmissions of the incoming call control signal is smaller than the reference value Nref4, the process returns to step S53.

  Thereafter, every time the retransmission of the incoming call control signal is detected in step S55, the number of retransmissions Nr of the incoming call control signal is continuously incremented in step S56. If Nr> Nref4 is determined in step S57, the process proceeds to step S58. In step S <b> 58, call restriction is instructed from the communication method selection unit 5 to the communication unit 6. In step S <b> 59, the call restriction is notified from the communication unit 6 to the input / output device 10, and a message notifying the call restriction is displayed on the display unit of the input / output device 10. In step S60, the communication unit 6 performs call restriction in response to the call restriction command. In step S61, a busy response is returned to the partner terminal.

According to FIGS. 8 and 9 , when a shortage of bandwidth in the IP network is predicted, a further shortage of bandwidth can be prevented beforehand by restricting communication, so it is possible to prevent a reduction in call quality in an established session. It becomes like this.

FIG. 10 is a flowchart showing the operation of the first embodiment of the present invention. Here, the operation in the case where a call is made from IP telephone apparatus A to IP telephone apparatus B is mainly performed by IP telephone apparatus A on the calling side. The description will be given focusing on the operation.

  When a call origination operation is performed on the input / output device 10 of the IP telephone apparatus A, and this is detected in step S70, the call history is referred to in step S71, and the outgoing call control signal is transmitted at the previous call to the same destination. It is determined whether retransmission has been performed. If the outgoing call control signal has been retransmitted, the process proceeds to step S81, and it is determined whether or not the elapsed time from the previous outgoing call is equal to or longer than a predetermined time. If it is not longer than the predetermined time, the process proceeds to step S77, and the codec change is instructed from the communication method selection unit 5 to the codec unit 2 via the communication unit 6.

  In step S78, the codec change is notified from the communication unit 6 to the input / output device 10, and a message notifying the codec change is displayed on the display unit of the input / output device 10. In step S79, the codec unit 2 changes the codec method from the current G711 to G729 having a higher compression rate in response to the codec change command. In step S80, IP telephone apparatus B is transmitted again using the changed codec method. If retransmission does not occur in the transmission operation by the changed codec system, the retransmission history of the outgoing call control signal is reset, so that the codec system is returned to G711 at the next transmission.

  On the other hand, if it is determined in step S71 that the outgoing call control signal is not retransmitted at the time of the previous call, or if a predetermined time or more has passed since the previous call in step S81. If it is determined, the process proceeds to step S72. Similar to the first embodiment, at first, the transmission operation is repeated by the standard communication method, and when the number of retransmissions Ns of the outgoing call control signal exceeds the reference value Nref5, step S77 and subsequent steps. The codec system is changed in the same way.

  According to the present embodiment, the retransmission history of the outgoing call control signal is recorded and referred to at the next outgoing call, and when the occurrence of retransmission of the outgoing call control signal is expected, the codec method is more encoded. Since the system can be switched to a highly efficient system, it is possible to quickly cope with a codec system with a small bandwidth.

  Further, according to the present embodiment, even if the outgoing call control signal is retransmitted at the time of the previous outgoing call, if a predetermined time or more has passed since then and the possibility that the situation has improved is high, it is normal Since the transmission operation is performed, encoding by an appropriate encoding method becomes possible.

FIG. 11 is a flowchart showing the operation of the second embodiment of the present invention. Here, the operation in the case where a call is made from IP telephone apparatus A to IP telephone apparatus B is mainly performed by IP telephone apparatus A on the calling side. The description will be given focusing on the operation.

  When a call operation is performed on the input / output device 10 of the IP telephone apparatus A, and this is detected in step S90, the call history is referred to in step S91, and the outgoing call control signal is retransmitted at the previous call to the same call destination. It is determined whether or not the operation has been performed. If the outgoing call control signal has been retransmitted, the process proceeds to step S89, and it is determined whether or not the elapsed time from the previous outgoing call is equal to or longer than a predetermined time. If it is not longer than the predetermined time, the process proceeds to step S97, where the communication method selection unit 5 instructs the communication unit 6 to restrict outgoing calls. In step S <b> 98, transmission restriction is notified from the communication unit 6 to the input / output device 10, and a message notifying transmission restriction is displayed on the display unit of the input / output device 10. In step S99, the communication unit 6 performs transmission restriction processing in response to the transmission restriction, thereby restricting transmission.

  In contrast, in step S91, it is determined that the outgoing call control signal has not been retransmitted at the time of the previous call, or in step S89, a predetermined time or more has elapsed since the previous call. If it is determined, step S92 follows. Similar to the second embodiment, the transmission operation is initially repeated by the standard communication method, and when the number of retransmissions Ns of the outgoing call control signal exceeds the reference value Nref6, step S97 is performed. Proceeding thereafter, outgoing calls are similarly regulated.

  According to the present embodiment, the retransmission history of the outgoing call control signal is recorded and referred to at the time of the next outgoing call, and the outgoing call restriction is performed when the occurrence of the outgoing call control signal retransmission is expected. A quick response to the prevention of further lack of bandwidth becomes possible.

  Further, according to the present embodiment, even if the outgoing call control signal is retransmitted at the time of the previous outgoing call, if a predetermined time or more has passed since then and the possibility that the situation has improved is high, it is normal Since the transmission operation is performed, appropriate transmission regulation is possible.

FIG. 12 is a flowchart showing the operation of the third embodiment of the present invention. Here, the operation when IP telephone apparatus A receives an incoming call from IP telephone apparatus B is mainly performed by the IP telephone apparatus A on the receiving side. The description will be given focusing on the operation.

  In step S100, when an incoming call is detected by the communication unit 6, the incoming call history is referred to in step S101, and it is determined whether or not the incoming call control signal has been retransmitted at the previous incoming call from the same source. If the incoming call control signal has been retransmitted, the process proceeds to step S112, and it is determined whether or not the elapsed time from the previous incoming call is a predetermined time or more. If it is not longer than the predetermined time, the process proceeds to step S108, and the codec change is instructed from the communication method selection unit 5 to the codec unit 2 via the communication unit 6. In step S109, the codec change is notified from the communication unit 6 to the input / output device 10, and a message notifying the codec change is displayed on the display unit of the input / output device 10. In step S110, the codec unit 2 changes the codec method from the current G711 to G729 having a higher compression rate in response to the codec change command. In step S111, the changed codec system is notified to IP telephone apparatus B, and the codec system is similarly changed in IP telephone apparatus B.

  On the other hand, if it is determined in step S101 that the incoming call control signal has not been retransmitted at the previous incoming call, or if a predetermined time or more has passed since the previous incoming call at step S112. If it is determined, the process proceeds to step S102. Similar to the third embodiment, the incoming call operation is initially repeated in the standard communication method, and only when the number of retransmissions Nr of the incoming call control signal exceeds the reference value Nref3, Proceeding to S108 and thereafter, the codec method is changed in the same manner.

  According to the present embodiment, the retransmission history of the incoming call control signal is recorded and referred to at the next incoming call, and when the occurrence of the retransmission of the incoming call control signal is expected, the codec method is more encoded. Since the system can be switched to a highly efficient system, it is possible to quickly cope with a codec system with a small bandwidth.

FIG. 13 is a flowchart showing the operation of the fourth embodiment of the present invention. Here, the operation when IP telephone apparatus A receives an incoming call from IP telephone apparatus B is mainly performed by IP telephone apparatus A on the receiving side. The description will be given focusing on the operation.

  If an incoming call is detected by the communication unit 6 in step S113, the incoming call history is referred to in step S114, and it is determined whether or not the incoming call control signal has been retransmitted at the previous incoming call from the same source. If the incoming call control signal has been retransmitted, the process proceeds to step S125, and it is determined whether or not the elapsed time from the previous incoming call is a predetermined time or more. If it is not longer than the predetermined time, the process proceeds to step S121, and the communication method selection unit 5 instructs the communication unit 6 to restrict the call. In step S122, communication restriction is notified from the communication unit 6 to the input / output device 10, and a message notifying the call restriction is displayed on the display unit of the input / output device 10. In step S123, the communication unit 6 performs call restriction in response to the call restriction command. In step S124, a busy response is returned to the partner terminal.

  On the other hand, if it is determined in step S114 that the incoming call control signal has not been retransmitted when the previous call is received, or if a predetermined time or more has elapsed since the previous call in step S125. If it is determined, the process proceeds to step S115, and similarly to the fourth embodiment, the incoming call operation is initially repeated by the standard communication method, and only when the number of retransmissions Nr of the incoming call control signal exceeds the reference value Nref4, Proceeding to S121 and thereafter, outgoing call restriction is performed in the same manner.

  According to the present embodiment, the history of retransmission of the incoming call control signal is recorded and referred to at the time of the next incoming call, and when the occurrence of retransmission of the incoming call control signal is expected, the outgoing call restriction is implemented. This enables a quick response to the prevention of further lack of bandwidth.

FIG. 14 is a flowchart showing another operation of changing the codec method according to the state of the IP network in the present invention, and FIG. 15 is a sequence flow thereof. Here, the explanation will be made focusing on the operation of IP telephone apparatus A from the state where IP telephone apparatus A and IP telephone apparatus B are communicating.

  In step S131, the communication monitoring unit 4 determines whether or not the fluctuation of the received packet is equal to or greater than a predetermined reference value. If it is equal to or greater than the reference value, it is determined that the bandwidth is insufficient and the process proceeds to step S133. On the other hand, if the fluctuation is less than the predetermined reference value, the process proceeds to step S132, and the communication monitoring unit 4 determines whether or not the loss of the received packet is greater than or equal to the predetermined reference value. If it is equal to or greater than the reference value, it is determined that the bandwidth is insufficient, and the process proceeds to step S133.

  In step S133, the communication method selection unit 5 instructs the codec unit 2 to change the codec via the communication unit 6. In step S134, the codec change is notified from the communication unit 6 to the input / output device 10, and a message notifying the codec change is displayed on the display unit of the input / output device 10. In step S135, the codec unit 2 changes the codec system from the current G711 to G729 having a higher compression rate in response to the codec change command. In step S136, the changed codec is notified to IP telephone apparatus B, and the codec system is similarly changed in IP telephone apparatus B.

According to FIGS. 14 and 15 , when the shortage of the IP network bandwidth is predicted, the codec method is switched to a method with higher coding efficiency, so that a call with a smaller bandwidth is possible.

Next, an operation when an IP network or a PSTN is selected according to the state of the IP network in the present invention will be described. FIG. 16 is a functional block diagram showing the configuration of the main part of the voice IP telephone apparatus in this case, and the same reference numerals as those in FIG. 1 represent the same or equivalent parts. Here, a PSTN interface 7 for communicating with a partner apparatus via a PSTN (Public Switched Telephone Networks) is provided so that communication can be selectively performed in either the IP network or the PSTN according to the bandwidth of the IP network . .

FIG. 17 is a flowchart showing the operation when selecting an IP network or PSTN according to the state of the IP network according to the present invention (particularly, the transmission side) , and FIG. 18 is a sequence flow thereof. Here, the operation when making a call from IP telephone apparatus A to IP telephone apparatus B will be described mainly focusing on the operation of IP telephone apparatus A on the caller side.

  When a transmission operation is performed on the input / output device 10 of the IP telephone apparatus A, and this is detected in step S141, the number Ns of retransmissions of the outgoing call control signal managed by the communication monitoring unit 4 is reset in step S142. The In step S143, a transmission operation is executed by the communication unit 6, and a transmission message addressed to the IP telephone apparatus B is transmitted via the LAN interface.

  If a response packet is returned from IP telephone apparatus B of the communication partner and this is detected in step S144, the process proceeds to a predetermined session establishment procedure. On the other hand, if a time-out occurs before a response is detected, the process proceeds to step S145, where the number Ns of retransmissions of the outgoing call control signal is incremented. In step S146, the communication method selection unit 5 compares the number Ns of retransmissions of the outgoing call control signal with a reference value Nref8. Initially, since it is determined that the number of retransmissions Ns of the outgoing call control signal is smaller than the reference value Nref8, the process returns to step S143, and the outgoing call control signal is retransmitted from the communication unit 6. In step S144 and subsequent steps, the same processing as described above is repeated. If there is no response, the number Ns of retransmissions of the outgoing call control signal continues to be incremented in step S145.

  Thereafter, when it is determined in step S146 that Ns> Nref8, the process proceeds to step S147, and the path switching is instructed from the communication method selection unit 5 to the communication unit 6. In step S148, the communication unit 6 notifies the input / output device 10 of the route switching, and a message for switching the route to the PSTN is displayed on the display unit of the input / output device 10. In step S149, in response to the path switching instruction, the communication unit 6 executes a path switching process for switching the path from the packet switching network via the LAN interface to the circuit switching network via the PSTN interface. In step S150, IP telephone apparatus B is transmitted again via the PSTN via the PSTN interface 7.

According to FIGS. 17 and 18 , when a shortage of IP network bandwidth is predicted, communication via the IP network is switched to PSTN, so high-quality communication is ensured even if the IP network bandwidth is low. become able to.

FIG. 19 is a flowchart showing the operation when the IP network or PSTN is selected according to the state of the IP network according to the present invention (particularly, the receiving side) . Here, IP telephone apparatus A receives an incoming call from IP telephone apparatus B. The operation in this case will be described mainly focusing on the operation of the IP telephone device A on the receiving side.

  When a call operation is performed on the input / output device 10 of the IP telephone apparatus A and this is detected in step S153, the call history is referred to in step S154, and whether or not the call control signal has been retransmitted at the previous call. Is determined. If the outgoing call control signal has been retransmitted, the process proceeds to step S160 where the communication method selection unit 5 instructs the communication unit 6 to switch the route.

  In step S <b> 161, path switching is notified from the communication unit 6 to the input / output device 10, and a message informing the path switching is displayed on the display unit of the input / output device 10. In step S162, in response to the path switching command, the communication unit 6 executes a path switching process for switching the path from the packet switching network via the LAN interface to the circuit switching network via the PSTN interface. In step S163, IP telephone apparatus B is transmitted again through the switched route.

  On the other hand, if it is determined in step S154 that the outgoing call control signal has not been retransmitted at the time of the previous call, the process proceeds to step S155, and the standard communication method is initially used as in the fifth embodiment. When the calling operation is repeated and the number of retransmissions Ns of the outgoing call control signal exceeds the reference value Nref9, the process proceeds to step S160 and the same, and the path is switched in the same manner.

According to FIG. 19, when a retransmission history of an outgoing call control signal is recorded and referred to at the time of next outgoing call and retransmission of the outgoing call control signal is expected, communication via the IP network is performed via the PSTN. Therefore, even if the bandwidth of the IP network is reduced, it is possible to quickly respond to ensuring high-quality communication.

In the above, the number of retransmissions Ns of the outgoing call control signal representing the state of the network, the number of retransmissions Nr of the incoming call control signal, the fluctuation of the received packet, or the lost number of the received packet exceeds a predetermined reference value, respectively. However, the present invention is not limited to this, and each communication control may be executed in stages according to the state of the network. good.

FIG. 20 is a flowchart showing an operation when performing communication control stepwise according to the state of the IP network in the present invention. Here, control for executing each communication control stepwise according to the network state The procedure will be described mainly focusing on the operation of the IP telephone device A on the caller side, taking as an example the case of making a call from the IP telephone device A to the IP telephone device B.

  When a call operation is performed on the input / output device 10 of the IP telephone apparatus A, and this is detected in step S171, the number Ns of retransmissions of the outgoing call control signal managed by the communication monitoring unit 4 is reset in step S172. The In step S173, a transmission operation is executed by the communication unit 6, and a transmission message addressed to the IP telephone apparatus B is transmitted via the LAN interface. At this time, the standard communication method is selected in the communication method selection unit 5, and in response to this, G711 is selected as the codec method in the codec unit 2.

If a response packet is returned from IP telephone apparatus B of the communication partner and this is detected in step S174, the process proceeds to a predetermined session establishment procedure. On the other hand, if a time-out occurs before a response is detected, the process proceeds to step S175, and the number Ns of retransmissions of the outgoing call control signal is incremented. In steps S176, S180, and S184, the communication method selection unit 5 compares the number Ns of retransmissions of the outgoing call control signal with reference values Nref2, Nref8, and Nref1, respectively. Here, the magnitude relationship of each reference value is set to Nref2>Nref8> Nref1.

  Initially, since it is determined that the number of retransmissions Ns of the outgoing call control signal is smaller than the reference value Nref1, the process returns to step S173, and the outgoing call control signal is retransmitted from the communication unit 6. In step S174 and thereafter, the same processing as described above is repeated. If there is no response, the number Ns of retransmissions of the outgoing call control signal continues to be incremented in step S175.

  Thereafter, when it is determined in step S184 that Ns> Nref1, the process proceeds to step S185, where the codec unit 2 is instructed from the communication method selection unit 5 to the codec unit 2 via the communication unit 6. In step S186, the codec change is notified from the communication unit 6 to the input / output device 10, and a message notifying the codec change is displayed on the display unit of the input / output device 10. In step S187, the codec unit 2 changes the codec system from the current G711 to G729 having a higher compression rate in response to the codec change command.

  Thereafter, the process returns to step S173, and the outgoing call control signal is retransmitted from the communication unit 6 by the new codec method (G729). In step S174 and thereafter, the same processing as described above is repeated. If there is no response, the number Ns of retransmissions of the outgoing call control signal continues to be incremented in step S175.

  If the number Ns of retransmissions of the outgoing call control signal exceeds Nref8, and this is detected in step S180, the process proceeds to step S181, and the path switching is instructed from the communication method selection unit 5 to the communication unit 6. In step S182, the communication unit 6 notifies the input / output device 10 of the route switching, and a message for switching the route to the PSTN is displayed on the display unit of the input / output device 10. In step S183, in response to the route switching instruction, the communication unit 6 executes a route switching process for switching the route from the packet switching network via the LAN interface to the circuit switching network via the PSTN interface.

  Thereafter, the process returns to step S173, and the communication unit 6 transmits the IP telephone apparatus B again via the PSTN interface 7 via the PSTN. In step S174 and thereafter, the same processing as described above is repeated. If there is no response, the number Ns of retransmissions of the outgoing call control signal continues to be incremented in step S175.

  When the number Nss of retransmissions of the outgoing call control signal exceeds Nref2, and this is detected in step S176, the process proceeds to step S177, and outgoing communication restriction is instructed from the communication method selection unit 5 to the communication unit 6. In step S178, transmission restriction is notified from the communication unit 6 to the input / output device 10, and a message notifying transmission restriction is displayed on the display unit of the input / output device 10. In step S179, the communication unit 6 responds to the outgoing call restriction and executes outgoing call restriction processing to restrict outgoing calls.

FIG. 2 is a functional block diagram showing a configuration of a voice IP telephone device according to the present invention. 6 is a flowchart showing an operation of changing a codec system according to the state of the IP network according to the present invention (especially, a transmission side) . Is a sequence flow showing the operation of FIG. 6 is a flowchart showing an operation of communication restriction (especially a transmission side) according to the state of the IP network in the present invention. Is a sequence flow showing the operation of FIG. 6 is a flowchart showing an operation of changing a codec system according to the state of the IP network according to the present invention (particularly, the receiving side) . 7 is a sequence flow showing the operation of FIG. 6 is a flowchart showing the operation of communication restriction (particularly the incoming side) according to the state of the IP network in the present invention. Is a sequence flow showing the operation of FIG. It is the flowchart which showed the operation | movement of 1st Embodiment of this invention. It is the flowchart which showed the operation | movement of 2nd Embodiment of this invention. It is the flowchart which showed the operation | movement of 3rd Embodiment of this invention. It is the flowchart which showed the operation | movement of 4th Embodiment of this invention. 6 is a flowchart showing another operation of changing the codec system according to the state of the IP network in the present invention. Is a sequence flow showing the operation of FIG. 14. Depending on the state of the IP network in the present invention is a functional block diagram showing the configuration of a voice over IP telephone apparatus in the case of selecting the IP network or PSTN. 6 is a flowchart showing an operation when an IP network or a PSTN is selected (especially a transmission side) according to the state of the IP network in the present invention. Is a sequence flow showing the operation of FIG. 17. 6 is a flowchart showing an operation when an IP network or a PSTN is selected according to the state of the IP network according to the present invention (particularly, the receiving side) . 6 is a flowchart showing an operation when performing communication control stepwise according to the state of the IP network in the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... LAN interface, 2 ... Codec part, 3 ... Decoding part, 4 ... Communication monitoring part, 5 ... Communication system selection part, 6 ... Communication part, 7 ... PSTN interface, 10 ... Input / output device

Claims (5)

A LAN interface that communicates with the other device via a LAN connected to the IP network;
Monitoring means for monitoring the state of the IP network;
A communication method selection means for selecting a communication method according to the state of the IP network;
Communication means for executing communication according to the selected communication method;
Including storage means for storing a communication history in communication;
If the communication history selection means does not store the outgoing call control signal or the incoming call control signal retransmission history in the previous communication in the communication history, the encoding is performed when the state of the IP network deteriorates from a predetermined reference state. Switch to a highly efficient codec communication method, or restrict communication, or switch the communication path from the IP network via the LAN interface to the PSTN via the PSTN interface, and the outgoing call control in the previous communication in the communication history The retransmission history of the signal or incoming call control signal is stored, and if the specified time or more has not passed since the previous call or incoming call, the codec communication system has high coding efficiency regardless of the IP network status. switching or regulating communication, or a communication path is switched from the IP network via the LAN interface to the PSTN via PSTN interface Voice IP telephone apparatus according to claim the door. The monitoring means monitors retransmission of an outgoing call control signal or an incoming call control signal , and the communication method selection means represents the state of the IP network by the number of retransmissions of the outgoing call control signal or the incoming call control signal. The voice IP telephone apparatus according to claim 1 . 2. The voice IP telephone apparatus according to claim 1 , wherein the monitoring unit monitors a fluctuation of a received packet, and the communication method selection unit represents the state of the IP network by the fluctuation. 2. The voice IP telephone apparatus according to claim 1 , wherein the monitoring unit monitors a lost number of received packets, and the communication method selecting unit represents the state of the IP network by the lost number. Before SL communication method selection means, the even communication history is stored in the retransmission history of outgoing call control signal or the incoming call control signal in the previous communication, if elapsed predetermined time from the last outgoing or incoming For example, regardless of the state of the IP network, switching to a codec communication method with low encoding efficiency, canceling communication restrictions, or switching a communication path to an IP network via a LAN interface The voice IP telephone apparatus according to any one of 1 to 4 .

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