JP2005184256A - Communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication system for achieving improved quality in sound signals even if a plurality of communication devices having an echo canceler for canceling echoes to a sound signal in the same direction are interposed on a channel. <P>SOLUTION: When a first communication device determines that the plurality of communication devices having the echo canceler are interposed on the call path between terminals for establishing the call path, the first communication device stops the echo canceler that the first communication device itself mounts, and transmits the stop request of the echo canceler that the second communication device mounts to the second communication device for removing echo components in the opposite direction. The second communication device stops the echo canceler of its own by receiving the stop request. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a communication system, and can be applied to a communication system in which, for example, a VoIP section for transmitting a voice signal by an IP packet exists on a communication path across an analog section for transmitting a voice signal by an analog voice signal. .

  In recent years, the popular VoIP technology has become widespread by consolidating data and voice by converting voice signals into IP packets, thereby reducing network costs and communication costs, and calls using broadband VoIP networks. There are various types of connections between terminals.

  For example, as shown in FIG. 2, a telephone for public telephone network (hereinafter referred to as a general telephone) 1 is connected to a VoIP network 7 via an ISDN connection device 2 and a VoIP network connection device 3, and the other is There is also a connection configuration in which the wireless IP terminal 4 is accommodated in the IP terminal accommodating device 5 and the IP terminal accommodating device 5 is connected to the VoIP network 7 via the VoIP network connecting device 6.

  Here, the telephone 1 and the VoIP network connection device 3 are in an analog section for transmitting voice signals as analog voice signals, and the VoIP network connection devices 3 and 6 are in a VoIP section for transmitting voice signals in IP packets. The VoIP network connection device 6 and the IP terminal accommodating device 5 are analog sections, and the space between the IP terminal accommodating device 5 and the wireless IP terminal 4 is a VoIP section.

  In IP packet transmission, the delay time is large, and if the influence of echo is superimposed, the sound quality may be further deteriorated. Therefore, an echo canceller is installed in an apparatus that terminates an IP packet.

  For example, if the wireless IP terminal 4 is an ISDN network connection terminal and a call is made via the IP terminal accommodating device 5 having the IP terminal accommodating function, the wireless IP terminal 4 and the IP terminal accommodating device 5 perform echo. The canceller is operated, and the echo component of the voice signal directed to the wireless IP terminal 4 is removed by the IP terminal accommodating device 5, while the echo component in the voice signal from the wireless IP terminal 4 is removed by the wireless IP terminal 4.

  Also, for example, when VoIP network connection devices 3 and 6 having an ISDN interface (S / T point interface) function are connected by subordinate devices 2 and 5, respectively, an echo canceller is operated to cancel the call echo. doing.

  Therefore, the audio signal from the wireless IP terminal 4 to the telephone set 1 is canceled by the wireless IP terminal 4 and is also canceled by the VoIP network connection device 6. The audio signal from the telephone 1 to the wireless IP terminal 4 is canceled by the VoIP network connection device 3, canceled by the wireless IP terminal 4, and also echoed by the IP terminal accommodating device 5. Canceled.

  That is, when an audio signal from the wireless IP terminal 4 to the telephone set 1 reaches the telephone set 1, the echo component is removed twice by removing the echo component by the wireless IP terminal 4 and removing the echo component by the VoIP network connection device 6. By removing the echo component by the VoIP network connection device 6 in the subsequent stage, the quality of the voice signal is lowered. Although the echo canceller is adaptively operated, it takes a long time for the echo canceller of the VoIP network connection apparatus 6 in the subsequent stage to operate so as not to substantially remove the echo component, and in the period up to that point, unnecessary echoes Cancel continues. Similarly, when an audio signal from the telephone 1 to the wireless IP terminal 4 reaches the wireless IP terminal 4, the echo component removal by the VoIP network connection device 3 and the echo component removal by the IP terminal accommodating device 5 are performed twice. The echo component is removed, and the quality of the voice signal is lowered by the removal of the echo component by the IP terminal accommodating device 5 in the subsequent stage.

  Therefore, there is a demand for a communication system that can achieve good quality of audio signals even when a plurality of communication devices having echo cancellers that perform echo cancellation for audio signals in the same direction are present on the speech path.

  In order to solve such a problem, the present invention provides a communication system in which a plurality of communication apparatuses having echo cancellers that perform echo cancellation for audio signals in the same direction can intervene on a communication path. (1) Between terminals that establish a communication path Then, it is judged that there are a plurality of communication devices having echo cancellers on the communication path, and the echo canceller mounted on the communication path is stopped, and other communication devices that remove the echo component in the reverse direction are A first communication device that sends a request to stop the installed echo canceller; and (2) a second communication device that stops its own echo canceller upon reception of the stop request from the first communication device. It is characterized by having.

  According to the present invention, when the first communication device determines that there are a plurality of communication devices having echo cancellers on the speech path between the terminals that establish the speech path, the first communication device stops the echo canceller installed by itself. A request to stop the echo canceller installed in the second communication device is sent to the second communication device that removes the echo component in the reverse direction so that the echo canceller of the second communication device is also stopped. As a result, it is possible to prevent the echo component removal operation from being performed repeatedly, and to suppress deterioration in communication quality.

(A) Embodiment Hereinafter, an embodiment of a communication system according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing a connection form of each device of the communication system according to this embodiment, and the same reference numerals are given to the corresponding parts to FIG. 2 described above.

  1, the communication system of this embodiment also includes a telephone 1, an ISDN connection device 2, a VoIP network connection device 3, a wireless IP terminal 4, an IP terminal accommodation device 5, and a VoIP network connection device 6 as components.

  In the case of this embodiment, one VoIP network connection device 6 accommodates not only a VoIP line with the VoIP network 7 but also a lifeline using a public telephone network (PSTN) 8 or an ISDN line. That is, the VoIP network connection device 6 alone accommodates a lifeline in order to cope with a lifeline call such as an emergency call (110, 119, etc.).

  In the case of this embodiment, as shown in FIG. 3, the VoIP network connection device 6 having the ISDN interface and the IP terminal accommodating device 5 having the ISDN interface are connected by the S / T interface.

  As shown in FIG. 4, the IP terminal accommodating apparatus 5 is configured such that the call sequence control unit 10 can perform on / off control of the operation of the echo canceller 11 that removes the echo component of the audio signal directed to the wireless IP terminal 4. As shown in FIG. 5, the VoIP network connection device 6 also allows the call sequence control unit 20 to perform on / off control of the operation of the echo canceller 21 that removes the echo component of the voice signal directed to the VoIP network 7.

  FIG. 6 is an explanatory diagram of the position of the echo canceller interposed during a call between the telephone set 1 and the wireless IP terminal 4.

  The echo canceller 31 of the VoIP network connection device 3 and the echo canceller 11 of the IP terminal accommodating device 5 are interposed on the path of the audio signal from the telephone set 1 to the wireless IP terminal 4. The echo canceller 30 of the wireless IP terminal 4 and the echo canceller 21 of the VoIP network connection device 6 are interposed on the path of the audio signal from the telephone 1 to the telephone 1.

  In this embodiment, at the time of a call between the telephone 1 and the wireless IP terminal 4, the echo canceling operation of the echo canceller 11 of the IP terminal accommodating device 5 and the echo canceller 21 of the VoIP network connection device 6 is stopped (off), and each direction The number of echo cancellers that operate effectively on the voice signal path is controlled by one (31, 30).

  FIG. 7 is an explanatory diagram of the position of the echo canceller interposed during the lifeline call by the wireless IP terminal 4.

  Since the lifeline is an analog section, the echo canceller 21 of the VoIP network connection device 6 does not intervene in this route, and only the echo canceller 11 of the IP terminal accommodating device 5 functions in the voice signal route to the wireless IP terminal 4. In the voice signal path from the wireless IP terminal 4, only the echo canceller 30 of the wireless IP terminal 4 functions.

  As described above, since the echo canceller to function differs depending on the other party or the like, the echo cancellers 11 and 21 are controlled to be turned on / off for each call through the call sequence for establishing the communication path.

  In this embodiment, control of the echo canceller 11 of the IP terminal accommodating apparatus 5 and the echo canceller 21 of the VoIP network connection apparatus 6 can be uniquely defined by the user of the circuit switching call control procedure (TTC standard JT-Q931). Use the message protocol.

  FIG. 8 is an explanatory diagram of the control contents of the echo canceller, FIG. 8 (A) shows the control contents from the IP terminal accommodating apparatus 5 to the VoIP network connection apparatus 6, and FIG. 8 (B) is the VoIP network connection apparatus. 6 shows notification contents (control contents) for the IP terminal accommodating apparatus 5.

  When the IP terminal accommodating device 5 issues a “VoIP connection confirmation request” to the VoIP network connecting device 6, the VoIP network connecting device 6 displays a “VoIP line connection display” to the IP terminal accommodating device 5 when the VoIP line is connected. Return it. However, when the corresponding call number does not exist or when the lifeline is connected, the VoIP network connection device 6 ignores the “VoIP connection confirmation request”.

  When the IP terminal accommodating device 5 issues a “start request” to the VoIP network connection device 6, the VoIP network connection device 6 starts the echo canceller 21 that is stopped. However, when the corresponding call number does not exist or is received during operation, the VoIP network connection device 6 ignores the “activation request”.

  Further, when the IP terminal accommodating device 5 issues a “stop request” to the VoIP network connection device 6, the VoIP network connection device 6 stops the echo canceller 21 in operation. However, the VoIP network connection device 6 ignores the “stop request” when the corresponding call number does not exist or is received while the call is stopped.

  Furthermore, when the IP terminal accommodating device 5 issues a “reset request” to the VoIP network connection device 6, the VoIP network connection device 6 resets the active echo canceller 21 (restarts echo cancellation from the initial state). ). However, the VoIP network connection device 6 ignores the “reset request” when the corresponding call number does not exist or is received while the call is stopped.

  When the “VoIP line connection display” described above is received from the VoIP network connection device 6 to the IP terminal accommodation device 5, the IP terminal accommodation device 5 performs the following control. When the IP terminal accommodating device 5 receives this notification after setting the call, it starts the echo canceller control to the VoIP network connection device 6, and the echo canceller 11 of itself (IP terminal accommodating device 5) stops until the call is restored. Let If the IP terminal accommodating device 5 does not receive the “VoIP line connection indication” in response to the “VoIP connection confirmation request”, the IP terminal accommodating device 5 does not execute the echo canceller control to the VoIP network connecting device 6 and itself (IP terminal accommodating device). The echo canceller 11 of 5) is normally operated.

  As shown in the first column of FIG. 9A, the VoIP network connection device 6 displays “VoIP connection display” when receiving a “VoIP connection confirmation request” from the IP terminal accommodating device 5 during VoIP connection. The IP terminal accommodating device 5 is notified.

  In addition, as shown in the second column of FIG. 9A, the VoIP network connection device 6 has an IP terminal in which the current operation state is when a call call is connected by VoIP and the echo canceller 21 is stopped by VoIP connection. When an “echo canceller activation request” is received from the storage device 5, the echo canceller 21 is activated.

  Further, as shown in the third column of FIG. 9 (A), the VoIP network connection device 6 has an IP terminal that is currently operating when the VoIP connection call is ended and the echo canceller 21 is activated in the VoIP connection. When the “echo canceller stop request” is received from the storage device 5, the echo canceller 21 is stopped.

  Furthermore, when the VoIP network connection device 6 receives an “echo canceller reset request” from the IP terminal accommodating device 5 during activation of the echo canceller 21, as shown in the fourth column of FIG. The echo canceller 21 is reset.

  As shown in FIG. 9 (B1), the IP terminal accommodating apparatus 5 sends a “call setting acceptance” (CALL PROC) message from the VoIP network connecting apparatus 6 at the time of transmission from the accommodated wireless IP terminal 4. When receiving, a “VoIP connection confirmation request” message is sent to the VoIP network connection device 6, and if it is an incoming call to the accommodated wireless IP terminal 4, a “call setting” is sent from the VoIP network connection device 6. When a (SETUP) message is received, a “VoIP connection confirmation request” message is sent to the VoIP network connection device 6.

  In addition, as shown in FIG. 9 (B2), the IP terminal accommodating apparatus 5 receives a “response” (CONNECT) message from the VoIP network connecting apparatus 6 at the time of transmission from the accommodated wireless IP terminal 4. Until reception, a “VoIP connection indication” message from the VoIP network connection device 6 is awaited, and if it is an incoming call to the accommodated wireless IP terminal 4, a “response confirmation” (CONNECT ACK) from the VoIP network connection device 6 is received. ) Wait until the “VoIP connection display” message from the VoIP network connection device 6 is received before the message is received. If the “VoIP connection display” message does not arrive even after the standby period has been exceeded, Do.

  Echo cancellers for controlling the echo canceller 21 to the VoIP network connection device 6 such as “VoIP connection confirmation request” message, “VoIP connection display” message, “start request”, “stop request”, “reset request”, etc. The control messages and the like follow the message format of the circuit-switched call control procedure (TTC standard JT-Q931), and examples of each are shown in FIG. 10, FIG. 11, and FIG.

  10-12, by inserting the additional information “INFORMATION” into the message type field, the unique information of the “VoIP connection confirmation request” message, the “VoIP connection display” message, and the echo canceller control message is inserted. Trying to get. The information element is defined by a variable length information element using “fixed shift: code group 7 (user-specific information element)”.

  A supplementary explanation will be given of the control message of the echo canceller. As shown in FIG. 12A, a field ECC for echo canceller control is provided as a user-specific information element, and a control bit (2 bits) CB representing the echo canceller control content is also prepared. For example, as shown in FIG. 12B, “00” in the control bit CB means “no control”, “01” in the control bit CB means “stop request”, and the control bit CB “10” means “start-up request”, and “11” in the control bit CB means “reset request”.

  Next, a call sequence at the time of call establishment (speech path establishment) between the IP terminal accommodating apparatus 5 and the VoIP network connection apparatus 6 at the time of transmission from the wireless IP terminal 4 will be described with reference to the sequence diagram of FIG.

  When receiving a “call setup” (SETUP) message (not shown) from the wireless IP terminal 4, the IP terminal accommodating apparatus 5 sends a “call setup” (SETUP) message to the VoIP network connection apparatus 6 ( S1). In response to this, the VoIP network connection device 6 transmits VoIP to the VoIP network 7 and returns a “call setting acceptance” (CALL PROC) message to the IP terminal accommodating device 5 (S2).

  At this time, the IP terminal accommodating apparatus 5 sends a “VoIP connection confirmation request” message, which is one of information (INFO) messages, to the VoIP network connecting apparatus 6 (S3), and the VoIP network connecting apparatus 6 is in VoIP connection. Therefore, a “VoIP connection display” message, which is one of information (INFO) messages, is returned to the IP terminal accommodating apparatus 5 (S4). Note that, when the lifeline is connected, the VoIP network connection device 6 does not return a “VoIP connection display” message.

  The VoIP network connection device 6 sends a “call” (ALERT) message to the IP terminal accommodating device 5 in response to a notification (not shown) during the other party's call from the VoIP network 7 (S5). In response to a partner response (not shown) from the network 7, a “response” (CONNECT) message is sent to the IP terminal accommodating apparatus 5 (S6). At this time, the IP terminal accommodating apparatus 5 returns a “response confirmation” (CONNECT ACK) message to the VoIP network connecting apparatus 6 (S7).

  Upon receipt of the “response confirmation” message, the VoIP network connection device 6 autonomously turns on the echo canceller 21 once the call connection is established.

  The IP terminal accommodating apparatus 5 turns off its own echo canceller 11 by establishing a VoIP connection via the VoIP network 7 and sends an echo canceller control message of “stop request”, which is one of information (INFO) messages, to the VoIP. It transmits to the network connection device 6 (S8). At this time, the VoIP network connection device 6 turns off (stops) the echo canceller 21 that has been turned on by receiving the echo canceller control message of “stop request”.

  Through the call sequence as shown in FIG. 13, among the echo cancellers 11, 21, 30, and 31 located as shown in FIG. 6, the echo cancellers 11 and 21 stop operating, and one each for each direction. Only the respective echo cancellers 30 and 31 execute the operation of removing the echo component of the audio signal.

  Next, a call sequence at the time of call establishment (speech path establishment) between the IP terminal accommodating apparatus 5 and the VoIP network connection apparatus 6 at the time of incoming to the wireless IP terminal 4 will be described with reference to the sequence diagram of FIG.

  When the VoIP network connection device 6 is notified of a VoIP incoming call from the VoIP network 7 (not shown), it sends a “call setup” (SETUP) message to the IP terminal accommodating device 5 (S11). In response to this, the IP terminal accommodating apparatus 5 sends an incoming call notification to the wireless IP terminal 4 (not shown) and returns a “call setting acceptance” (CALL PROC) message to the VoIP network connection apparatus 6. (S12).

  Thereafter, the IP terminal accommodating apparatus 5 sends a “VoIP connection confirmation request” message, which is one of information (INFO) messages, to the VoIP network connecting apparatus 6 (S13), and the VoIP network connecting apparatus 6 is in a VoIP connection state. Since it is reception, a “VoIP connection display” message which is one of information (INFO) messages is returned to the IP terminal accommodating apparatus 5 (S14). Note that, when the lifeline is connected, the VoIP network connection device 6 does not return a “VoIP connection display” message.

  The IP terminal accommodating device 5 sends a “call” (ALERT) message to the VoIP network connection device 6 in response to a notification (not shown) during the call from the wireless IP terminal 4 (S15). Upon notification of an off-hook response (not shown) from the IP terminal 4, a “response” (CONNECT) message is sent to the VoIP network connection device 6 (S16). Upon receiving the “response” message, the VoIP network connection device 6 autonomously turns on the echo canceller 21 once and establishes a response to the VoIP network 7 side. After waiting for the notification (not shown), a “response confirmation” (CONNECT ACK) message is returned to the IP terminal accommodating apparatus 5 (S17).

  The IP terminal accommodating apparatus 5 turns off its own echo canceller 11 by establishing a VoIP connection via the VoIP network 7 and sends an echo canceller control message of “stop request”, which is one of information (INFO) messages, to the VoIP. It transmits to the network connection device 6 (S18). At this time, the VoIP network connection device 6 turns off (stops) the echo canceller 21 that has been turned on by receiving the echo canceller control message of “stop request”.

  Through the call sequence as shown in FIG. 14, among the echo cancellers 11, 21, 30, and 31 located as shown in FIG. 6, the echo cancellers 11 and 21 stop operating, and one for each direction. Only the respective echo cancellers 30 and 31 execute the operation of removing the echo component of the audio signal.

  As described above, in order to avoid redundant operation of the echo canceller, it is necessary to stop both the local VoIP network connection device 6 and the echo canceller of the IP terminal accommodating device 5.

  However, when a call is made with a terminal other than the IP terminal accommodated in the IP terminal accommodating apparatus 5, the echo canceller is not operated in the IP terminal accommodating apparatus 5, so it is necessary to operate the echo canceller of the VoIP network connection apparatus 6. is there.

  In order to satisfy these conditions, when the IP terminal accommodating apparatus 5 is connected to the VoIP network connection apparatus 6, the operation of the echo canceller of the VoIP network connection apparatus 6 is controlled (operated / stopped) according to the type of the terminal that performs the call. There is a need.

  On the other hand, when the VoIP network connection device 6 accommodates a lifeline in addition to the VoIP line, when the VoIP network connection device 6 makes a call connection using the lifeline, the VoIP network depends on the type of the terminal that performs the call. It is not necessary to control the echo canceller 21 of the connection device 6, and it is necessary to perform the same operation as that of the conventional IP terminal accommodating device 5.

  In order to realize this, as described above, it is necessary to notify the IP terminal accommodating device 5 from the VoIP network connecting device 6 at the time of outgoing / incoming calls, and accordingly, the IP terminal accommodating device is notified. 5 controls the echo canceller of the VoIP network connection device 6.

  According to the above embodiment, when the IP terminal accommodating apparatus 5 and the VoIP network connecting apparatus 6 communicate via the VoIP network 7 through the message exchange during the call sequence of the IP terminal accommodating apparatus 5 and the VoIP network connecting apparatus 6, Since the echo cancellers 11 and 21 are stopped, for each of the methods, it is possible to prevent a plurality of echo cancellers from operating, and to prevent deterioration in voice communication quality due to the presence of the plurality of echo cancellers. it can.

  Further, not only the IP terminal accommodating device 5 but also other devices may be connected under the VoIP network connection device 6, and the VoIP network connection device 6 may connect the lifeline communication path. In such a situation, the echo canceller control can be appropriately executed by the IP terminal accommodating apparatus 5 taking the initiative and performing the echo canceller control.

(B) Other Embodiments In FIG. 1, it is described that the IP terminal accommodating device 5 accommodates only one wireless IP terminal 4, but the IP terminal accommodating device 5 includes a plurality of wireless IP terminals 4. It may be accommodated and function like a PBX. The IP terminal accommodating device 5 and the wireless IP terminal 4 are realized as, for example, a home device.

  Further, the IP terminal accommodating device 5 may be connected to the IP terminal (6) by wire.

  Unlike the configuration in FIG. 1, the configuration on the telephone 1 side in FIG. 1 is also a combination of an IP terminal accommodating device (corresponding to 5) and a VoIP network connection device 3. Also, the echo canceller may be stopped between the VoIP network connection devices 3 by performing processing similar to the above call sequence.

  In the embodiment described above, the present invention is applied to a communication system via the VoIP network 7, but the present invention can also be applied to other communication systems in which similar echo canceller problems occur. . For example, even in the case of international communication using artificial satellites, the type of each section in the communication path between terminals is different, and the echo cancellers of the respective parts operate redundantly, so that the present invention can be applied.

It is a block diagram which shows the example of a connection form between the terminals provided for a telephone call using the VoIP network of embodiment. It is a block diagram which shows an example of the connection form between the terminals used for a telephone call using a VoIP network for conventional problem description. It is explanatory drawing of the interface between the IP terminal accommodating apparatus and VoIP network connection apparatus of embodiment. It is a block diagram which shows the principal part structure inside the IP terminal accommodating apparatus of embodiment. It is a block diagram which shows the principal part structure inside the VoIP network connection apparatus of embodiment. It is explanatory drawing of the echo canceller position interposed when using the VoIP network of embodiment. It is explanatory drawing of the echo canceller position interposed at the time of the lifeline call of embodiment. It is explanatory drawing of the control content of the echo canceller of embodiment. It is explanatory drawing of the control conditions of the echo canceller of embodiment. It is explanatory drawing which shows the example of a format of the "VoIP connection confirmation request" message of embodiment. It is explanatory drawing which shows the example of a format of the "VoIP connection display" message of embodiment. It is explanatory drawing which shows the example of a format of the "echo canceller control" message of embodiment. It is a call sequence diagram between the IP terminal accommodating apparatus and the VoIP network connection apparatus at the time of transmission from the wireless IP terminal of the embodiment. It is a call sequence diagram between the IP terminal accommodating apparatus and the VoIP network connection apparatus at the time of incoming to the wireless IP terminal of the embodiment.

Explanation of symbols

3, 6 ... VoIP network connection device (second communication device), 4 ... wireless IP terminal, 5 ... IP terminal accommodating device (first communication device), 11, 21, 30, 31 ... echo canceller.

Claims (3)

In a communication system in which a plurality of communication apparatuses having an echo canceller that performs echo cancellation for an audio signal in the same direction can be interposed on a speech path,
It is determined that there are a plurality of communication devices having echo cancellers on the communication path between terminals that establish the communication path, and the echo canceller installed by itself is stopped and another communication apparatus that removes the echo component in the reverse direction is used. On the other hand, a first communication device that sends a stop request for an echo canceller installed in another communication device;
And a second communication device that stops its own echo canceller upon reception of a stop request from the first communication device.   The communication system according to claim 1, wherein the first communication device is a device closer to the terminal than the second communication device when viewed from the network. The communication system according to claim 1 or 2, wherein the network used for communication between the terminals is a VoIP network.

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