JP2017169005A - Ring back tone provision device and ring back tone provision method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of a situation in which a ring back tone RBT does not arrive at a user of a call origination terminal or a plurality of ring back tones are overlapped in a communication path being established, in the case that VoIP networks of a plurality of business companies are directly interconnected without using Public Switched Telephone Networks (PSTN).SOLUTION: On a gateway device 30 for performing interconnection between a plurality of business companies is mounted a function of a ring back tone provision device. The ring back tone provision device, which comprises a RBT sound source 31, determines the necessity of sending a ring back tone before establishing, by a call of a call origination terminal 11, a communication path between the call origination terminal 11 and a call incoming terminal 21; and, when sending a ring back tone is necessary, sends a ring back tone generated inside toward the call origination terminal 11. The necessity of sending a ring back tone is determined depending on whether or not a media packet comes from a call incoming side network 20. The determination is performed by monitoring actual media for a given time or on the basis of a content of a SIP header, SDP information, or the like.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a ringing tone providing apparatus and a ringing tone providing method, and relates to ringing tone control in a communication system that establishes a communication path between a plurality of networks.

  For example, a fixed telephone and a mobile phone are generally connected to a plurality of networks managed by different operators. Therefore, when a call is made between a fixed phone and a mobile phone, one network to which the fixed phone is connected and the other network to which the mobile phone is connected are connected to each other via a gateway. Then, a communication path (session) is established between the fixed phone and the mobile phone, and then the user starts a call.

  Also, when a call is made from a landline or mobile phone, an RBT (Ring Back Tone: ringing tone) is sent from the calling party to notify the caller that the caller is being called before establishing the communication path. Provided to the terminal. For example, a sound such as “Pururu ...” is used as the ringing tone RBT. At the time of mutual connection between conventional public switched networks (PSTN), it is common to provide a ring tone RBT by an exchange included in the called network.

  In addition, when interconnecting a plurality of VoIP (Voice over IP) networks, a connection via a public switched network (PSTN) is generally used, but in the future, an IP (Internet Protocol) based interconnect will be used. Transition to form is expected (see Non-Patent Document 1).

  Non-Patent Document 2 and Non-Patent Document 3 show examples of specific products of gateway devices arranged between networks when performing IP-based interconnection between networks. Note that none of the gateway devices of Non-Patent Literature 2 and Non-Patent Literature 3 has a special function as a ringing tone providing device.

Sakaya, Arai and Kanegae, “Standardization Activities for IP Interconnection Specifications”, NTT Technical Journal, July 1, 2014, Vol. 26, No. 7, p. 63-65. “Gateway between networks supporting NGN with high carrier grade reliability”, Business Communication, April 1, 2009, Volume 46, Number 4, p42-45. “Sonus SBC 5100”, [online], SONUS NETWORKS, INC., [Search January 25, 2016], Internet <URL: http: //www.sonus.net/en/products/session-border-controllers/ sonus-sbc-5100>

  By the way, when a plurality of networks are interconnected, there is no clear standard provision as to whether the ringing tone RBT is provided by the calling side network or the called side network. Therefore, in the IP network, the calling terminal may generate the ringing tone RBT, and the called network may generate the ringing tone RBT.

  For example, according to the document “JT-Q3402” defined by TTC (Information and Communication Technology Committee), the following matters are defined. “The calling terminal generates a sound source when receiving a 180 (Ringing) response that does not include SDP (Session Description Protocol)” Note that this standard is mainly applied to fixed terminals. Also, in the “GSMA IR92” standard, which is mainly used as a specification for mobile phone terminals, the ringing tone RBT is expected to be generated at the calling terminal.

  That is, when the standards of “TTC JT-Q3402” and “GSMA IR92” are adopted, it is not necessary for the network side to generate the ring tone RBT and send it to the calling terminal. However, in reality, there is a service that provides a sound (such as music) equivalent to the ring tone RBT to the calling terminal from the called network while calling the called party. In addition, depending on the policy of the operator, a case where a ringing tone is transmitted from the destination network is also assumed.

  Currently, when connecting between operator networks, a system is generally configured to pass through a public switched network PSTN. However, since PSTN equipment will eventually reach the limit of maintenance, the interconnection of IP networks is expected to progress in the future.

  However, since there is no clear definition as to whether the ringing tone RBT is provided by the calling side network or the called side network as described above, there is a high possibility that a problem will occur particularly when the IP networks are interconnected. In other words, both the equipment on the originating network and the equipment on the terminating network are in a situation where the other party expects the ringing tone RBT to be generated and transmitted, and the ringing tone RBT does not reach the user of the originating terminal. The situation is feared.

  As a result, the user of the calling terminal recognizes a silent state instead of the ringing tone RBT even though the calling is actually being performed. Then, the user of the calling terminal assumes that the connection has failed, and the connection is abandoned during the call. Therefore, communication is not established.

  In order to realize an IP network connection that does not cause a problem in the above situation, the function related to the transmission of the ring tone RBT must be modified in either the originating network or the terminating network. Requires renovation of the terminal or in-network device, which requires time and cost.

More specific contents of the above items will be described below with reference to the drawings.
Examples of a ringing tone transmission operation in a general communication system in which a plurality of networks are interconnected are shown in FIGS. 7, 8, and 9, respectively.

  The communication system shown in FIG. 7 is an example in which a ringing tone is generated at a calling terminal 53 corresponding to a fixed terminal. In this communication system, it is assumed that a calling terminal 53 corresponding to a fixed terminal is connected to the calling side network 51 and a called terminal 54 is connected to the called side network 52. Accordingly, the communication system is configured to interconnect the originating network 51 and the terminating network 52 in order to enable communication between the originating terminal 53 and the terminating terminal 54. Here, it is a general situation that the originating side network 51 and the terminating side network 52 are owned or managed by different communication carriers, for example.

  As shown in FIG. 7, when establishing a communication path with the destination terminal 54 by a call of the source terminal 53, the source terminal 53 makes a SIP (Session Initiation Protocol: session) to the destination terminal 54 in the first sequence Q31. (Established protocol) request “INVITE with SDP (offer)” is sent to the originating network 51. The calling side network 51 relays this request “INVITE with SDP (offer)” in sequence Q32 toward the called side network 52 to which the called destination terminal 54 is connected.

  The destination network 52 relays this request “INVITE with SDP (offer)” to the destination terminal 54 in sequence Q33. As a result, the destination terminal 54 receives the SIP request “INVITE with SDP (offer)” from the calling terminal 53.

  The terminating terminal 54 returns a SIP response “180 without SDP” to the terminating network 52 in sequence Q34. The destination network 52 relays this response “180 without SDP” to the source network 51 in sequence Q35. The originating network 51 relays this response “180 without SDP” to the originating terminal 53 in sequence Q36. As a result, the calling terminal 53 receives the response “180 without SDP” from the called terminal 54.

  In the communication system shown in FIG. 7, the calling terminal 53 recognizes that the called terminal 54 is being called by the response “180 without SDP” received from the called terminal 54. Then, ringing tone RBT is generated in sequence Q37 using a sound source built in calling terminal 53 itself. This ringing tone RBT is output as a real sound from a speaker (not shown) of the calling terminal 53 so that it can be perceived by the user who operates the calling terminal 53, that is, the caller.

  For example, in a communication system that operates in accordance with the provisions of the TTC document “JT-Q3402”, the sequence shown in FIG. 7 is performed, so that the calling terminal 53 itself outputs the ring tone RBT. In this case, the destination network 52 does not need to send the ring tone RBT.

  The communication system shown in FIG. 8 is an example in which a ringing tone RBT is transmitted from a sound source server (not shown) of the destination network 62. Also in this communication system, when establishing a communication path with the called terminal 64 by a call from the calling terminal 63, the calling terminal 63 issues a SIP request “INVITE with SDP (offer)” in the first sequence Q41. Send to the side network 61. Receiving this, the originating network 61 relays this request “INVITE with SDP (offer)” to the called network 62 to which the called terminal 64 is connected in sequence Q42.

  The destination network 62 relays this request “INVITE with SDP (offer)” to the destination terminal 64 in sequence Q43. As a result, the destination terminal 64 receives the SIP request “INVITE with SDP (offer)” from the source terminal 63. The destination terminal 64 returns a SIP response “183 with SDP” to the destination network 62 in sequence Q44. The terminating network 62 relays the SIP response “183 with SDP” to the originating network 61 in sequence Q45. This response “183 with SDP” indicates that the destination network 62 intends to play some medium, in this case, the ringing tone RBT.

  The originating network 61 relays this response “183 with SDP” to the originating terminal 63 in sequence Q46. As a result, the calling terminal 63 receives the response “183 with SDP” from the called terminal 64. In addition, destination network 62 transmits a media packet of ringing tone RBT by a sound source server (not shown) in sequence Q47. This ringing tone RBT reaches the calling terminal 63 via the calling side network 61. Further, since the calling terminal 63 recognizes that the media packet has arrived by the received response “183 with SDP”, the calling terminal 63 processes and reproduces the media packet of the ring tone RBT received via the calling side network 61. The sound of the ring tone RBT is output from a speaker (not shown).

  On the other hand, the communication system shown in FIG. 9 is an example in which a ringing tone RBT is transmitted from the PSTN 72 which is a public exchange network. In this communication system, a calling terminal 73 corresponding to a fixed terminal is connected to a calling side network 71, and a called terminal (not shown) is connected to a called side network (not shown) different from the calling side network 71. Assume a connected situation. The communication system uses a PSTN 72, which is a public exchange network, to interconnect the originating network 71 and the terminating network. As shown in FIG. 9, when a plurality of networks are interconnected using the PSTN 72, it is common to provide a ringing tone RBT by an exchange included in the destination network.

  Also in the communication system shown in FIG. 9, when establishing a communication path with a destination terminal (not shown) by a call from the source terminal 73, the source terminal 73 makes an SIP request “INVITE with SDP” in the first sequence Q 51. (offer) ". Upon receiving this, the originating network 71 sends a message IAM (Initial Address Message) to the PSTN 72 in sequence Q52. This message IAM means that a line connection is requested to a designated partner, and includes a sender telephone number and a receiver telephone number as main information.

  The PSTN 72 exchanges messages with the called side network to which the called terminal is connected according to the message IAM received from the calling side network 71. Then, in sequence Q53, the PSTN 72 sends a message CPG (Call Progress) toward the originating network 71. This message CPG has a meaning of notifying the progress of a call or the like.

  In response to the message CPG received from the PSTN 72, the originating network 71 sends a response “183 with SDP” to the originating terminal 73 in sequence Q54. Further, since the ring tone RBT generated in the destination network is input to the PSTN 72, the PSTN 72 transfers the ring tone RBT to the originating network 71 in sequence Q55. This ringing tone RBT is further transferred from the calling side network 71 toward the calling terminal 73.

  Further, since the calling terminal 73 recognizes that the media packet arrives by the response “183 with SDP” received in the sequence Q54, the calling terminal 73 processes the media packet of the ring tone RBT received via the calling side network 71. It is reproduced and output as the sound of the ring tone RBT.

  When a plurality of networks are interconnected via the PSTN 72 as in the communication system shown in FIG. 9, there is no problem at present regarding the transmission of the ring tone RBT. However, as shown in Non-Patent Document 1, in a situation where a plurality of IP networks are interconnected without using the PSTN 72, for example, the communication system shown in FIG. 7 and the communication system shown in FIG. Are assumed to be mixed.

  FIG. 10 shows a specific example in a case where trouble is caused in providing a ringing tone in a general communication system in which a plurality of networks are interconnected without using PSTN. In the communication system shown in FIG. 10, a calling terminal 83 corresponding to a fixed terminal is connected to the calling network 81 and a called terminal 84 corresponding to a mobile phone terminal is connected to the called network 82. Is assumed. Accordingly, the communication system is configured to interconnect the calling side network 81 and the called side network 82 without using PSTN in order to enable communication between the calling terminal 83 and the called terminal 84. Here, the calling side network 81 and the called side network 82 are owned or managed by different communication carriers, for example. Therefore, each of the calling side network 81 and the called side network 82 cannot know the status of the other party's terminal, except for the items defined by the standard.

  As shown in FIG. 10, when establishing a communication path with the destination terminal 84 by the call of the source terminal 83, in sequence Q60, on the line between the destination terminal 84 and the destination side network 82, Resources for media transfer are not secured. At this time, the calling terminal 83 sends a SIP request “INVITE with SDP (no offer, no precondition)” to the called terminal 84 toward the calling side network 81 in the first sequence Q61. Receiving this, the originating network 81 relays the request “INVITE with SDP (offer, no precondition)” in sequence Q 62 toward the called network 82 to which the called destination terminal 84 is connected.

  The destination network 82 relays this request “INVITE with SDP (no offer, no precondition)” to the destination terminal 84 in sequence Q63. As a result, the destination terminal 84 receives the SIP request “INVITE with SDP (without offer, precondition)” from the source terminal 83. The destination terminal 84 sends an SIP response “183 with SDP (answer)” to the input request toward the destination side network 82 in sequence Q64.

  The destination network 82 relays this response “183 with SDP (answer)” to the source network 81 in sequence Q65. In addition, the originating network 81 relays this response “183 with SDP (answer)” to the originating terminal 83 in sequence Q66. As a result, the calling terminal 83 receives the response “183 with SDP (answer)” from the called terminal 84.

  In the communication system shown in FIG. 10, since the calling terminal 83 includes “183 with SDP (answer)” in the response received in sequence Q66, some medium, that is, the ringing tone RBT is not transmitted to the destination network 82. It is expected to be transmitted from the illustrated sound source server.

  In order to enable transfer of some media, a resource for media transfer is secured on the line between the called terminal 84 and the called network 82 in sequence Q67. However, in the example shown in FIG. 10, it is assumed that there is no intention to send the ring tone RBT to the destination network 82. Therefore, the destination terminal 84 sends a response “180 without SDP” in sequence Q68. This response “180 without SDP” is expected to generate the ring tone RBT on the calling terminal 83 side.

  The destination network 82 relays this response “180 without SDP” to the source network 81 in sequence Q69. Further, the originating network 81 relays this response “180 without SDP” to the originating terminal 83 in sequence Q70. As a result, the calling terminal 83 receives the response “180 without SDP” from the called terminal 84.

  The calling terminal 83 operates in accordance with the provisions of the TTC document “JT-Q3402”. Since this calling terminal 83 receives the response “183 with SDP (answer)” in sequence Q66 before receiving the response “180 without SDP” in sequence Q70, the ringing tone RBT is transmitted from the destination network 82. Expect to be. Therefore, the calling terminal 83 itself does not generate the ring tone RBT internally.

  However, since the called terminal 84 actually operates in accordance with the regulations of “GSMA IR92”, the called terminal 84 does not send out the ringing tone RBT. Therefore, even though the calling terminal 83 is calling the called terminal 84, the ringing tone RBT is not output, and the user recognizes that there is no sound. For this reason, the user assumes that the call has failed and cancels the call.

The ring tone RBT problem occurs in the communication system shown in FIG. 10 due to a difference in policy between operators of each network and a difference in communication standards.
For example, in the standard of “GSMA IR.92-IMS Profile for Voice and SMS (v9.0)” that is mainly referred to by mobile phone terminals, in summary, as an important matter in the situation like the sequence Q64 in FIG. The following items are stipulated.

(1) When receiving the request “INVITE”, it is necessary to transmit a response “183 (Session Progress)” including the SDP.
(2) When receiving the request “INVITE”, the response “180 (Ringing)” must not be transmitted until the resource is secured.

  On the other hand, according to the standard of “TTC JT-Q.3402” that is mainly referred to by the fixed terminal, in summary, as an important matter corresponding to the situation of the calling terminal 83 that has received the responses of the sequences Q66 and Q70 of FIG. The following items are stipulated.

(3) When the response “180 (Ringing)” not including the SDP is received, the ringing tone must be generated from its own sound source from that point.
(4) When the terminal receives the response “1xx” including the SDP, the terminal must be able to establish early media by connecting paths. Thereafter, the terminal must continue to play the received media regardless of the presence or absence of the SDP regardless of the response “1xx” received in the same dialog. That is, the media replacement process should not be performed.

  In the communication system shown in FIG. 10, the destination terminal 84 transmits a response “183” including the SDP in sequence Q64 in accordance with the above-mentioned rule (1). In addition, the destination terminal 84 transmits a response “180” without SDP in sequence Q68 after succeeding in securing the resource in accordance with the provision of (2) above. In addition, when the destination terminal 84 transmits the response “180” without SDP, the calling terminal 83 expects that the calling terminal 83 generates its own ringing tone RBT according to the provision of (3) above. Sound RBT is not sent out.

  However, the calling terminal 83 shown in FIG. 10 operates in accordance with the provision of the above (4) since the SDP is included in the response “183” received in the sequence Q66. That is, even if the response “180” is received in the next sequence Q70, it is expected that the media packet of the ringing tone RBT is transmitted from the destination network 82, and the calling terminal 83 itself generates the ringing tone RBT. Absent. As a result, as shown in FIG. 10, the calling terminal 83 becomes silent during a call.

  The present invention has been made in view of the above situation, and even when there is no clear agreement regarding a ringing tone transmission policy among a plurality of networks connected to each other, the present invention is issued when a called terminal is called. An object of the present invention is to provide a ringing tone providing apparatus and a ringing tone providing method capable of reliably giving a ringing tone to a user of a terminal.

(1) Installed in a gateway that interconnects the first network to which the calling terminal is connected and the second network to which the called terminal is connected; A ringing tone providing apparatus for providing a predetermined ringing sound indicating that the calling terminal is being called to the calling terminal before establishing a communication path with the terminal,
A ring tone generator for generating a ring tone;
Before establishing a communication path between the calling terminal and the called terminal by a call of the calling terminal, it is determined whether or not a ringing tone needs to be sent from the ringing tone generation unit, and when a ringing tone needs to be sent Is a ringing tone transmission control unit that transmits a ringing tone from the ringing tone generation unit to the calling terminal;
Is provided.

  According to this ringing tone providing apparatus, when the second network on the called side does not send out a ringing tone, the ringing tone generated by the ringing tone generation unit under the control of the ringing tone transmission control unit is transmitted from the gateway. It can be sent to the calling terminal. In addition, when the second network on the called side transmits a ringing tone, the ringing tone is not transmitted from the ringing tone generation unit, and therefore the ringing tone of the second network is preferentially delivered to the calling terminal. be able to.

(2) The ringing tone transmission control unit monitors the presence / absence of a media packet input from the second network after receiving a predetermined response from the second network to the communication path establishment request, If the media packet is not detected within a predetermined time, it is determined that the ringing tone needs to be transmitted.
The ringing tone providing apparatus according to (1) above.

  According to this ringing tone providing apparatus, it is possible to determine whether or not the second network on the called side is sending out a ringing tone by monitoring the presence or absence of a media packet. If a media packet is not detected within a predetermined time, it is highly likely that the second network on the callee side will not send out a ringing tone, so that the ringing tone generated by the ringing tone generation unit is transmitted from the gateway to the source. It is necessary to send it to the terminal.

(3) When the ringing tone transmission control unit receives a predetermined response from the second network in response to the communication path establishment request, the ringing tone transmission unit is configured to respond to the content of the specific information included in the response. Determining whether it is necessary to send a ringing tone from the generator;
The ringing tone providing apparatus according to (1) above.

  According to this ringing tone providing apparatus, since it is determined whether or not it is necessary to send out the ringing tone from the ringing tone generation unit according to the content of the specific information included in the response, the identification result immediately after receiving the response Can be obtained. Therefore, it is possible to shorten the waiting time from when the call of the called terminal is started until the ringing tone is transmitted.

(4) When receiving a predetermined response from the second network in response to the communication path establishment request, the ringing tone transmission control unit is based on the content of a predetermined database that holds information about the called terminal. Determining whether or not it is necessary to send a ring tone from the ring tone generator;
The ringing tone providing apparatus according to (1) above.

  According to this ringing tone providing apparatus, since it is determined whether or not it is necessary to send the ringing tone from the ringing tone generation unit based on the contents of the database, an identification result can be obtained immediately after receiving the response. Therefore, it is possible to shorten the waiting time from when the call of the called terminal is started until the ringing tone is transmitted.

(5) The response is any one of SIP (Session Initiation Protocol) 180 response, 181 response, 182 response, and 183 response.
The ringing tone providing device according to (3) or (4) above.

  According to this ringing tone providing apparatus, it is determined whether or not it is necessary to send a ringing tone based on a SIP 18x response, or information on the necessity of sending a ringing tone is obtained by obtaining information on the destination terminal when receiving this response. Can be acquired.

(6) When the ringing tone transmission control unit recognizes that the ringing tone transmission from the ringing tone generation unit is unnecessary, the ringing tone transmission control unit transfers a media packet input from the second network to the first network.
The ringing tone providing apparatus according to (1) above.

  According to the ringing tone providing apparatus, when the ringing tone is transmitted as a media packet from the second network on the called side, the ringing tone can be delivered to the calling terminal by transferring the media packet as it is. . Therefore, the user of the calling terminal can use not only the ringing tone generated by the ringing tone providing apparatus itself but also the special ringing tone provided as a unique service by the second network on the called side.

(7) controlling a communication system including a first network to which the calling terminal is connected, a second network to which the called terminal is connected, and a gateway interconnecting them, and calling the calling terminal The ringing tone providing method for providing the calling terminal with a predetermined ringing sound indicating that the calling terminal is being called before establishing a communication path between the calling terminal and the called terminal Because
Before establishing a communication path between the calling terminal and the called terminal by a call of the calling terminal, the gateway determines whether or not a ringing tone needs to be transmitted. Sending the generated ringing tone toward the calling terminal;
It is characterized by that.

  According to this ringing tone providing method, the ringing tone generated by the gateway can be transmitted from the gateway toward the calling terminal when the second network on the called side does not transmit the ringing tone. When the second network on the called side sends a ringing tone, the gateway itself does not generate a ringing tone, so that the ringing tone of the second network can be preferentially delivered to the calling terminal. it can.

  According to the ringing tone providing apparatus and ringing tone providing method of the present invention, even when there is no clear agreement regarding the ringing tone transmission policy among a plurality of networks connected to each other, the ringing tone providing method is provided when a called terminal is called. A ringing tone can be reliably given to the user of the terminal. That is, when the second network on the called side does not transmit a ringing tone, the ringing tone generated by the gateway can be automatically transmitted from the gateway to the calling terminal. When the second network on the called side sends a ringing tone, the gateway itself does not generate a ringing tone, so that the ringing tone of the second network can be preferentially delivered to the calling terminal. it can.

It is a sequence diagram which shows the outline | summary of a structure and operation | movement of a communication system including the ringing tone provision apparatus in embodiment of this invention. It is a flowchart which shows the characteristic operation | movement (1) of the gateway apparatus contained in the communication system shown in FIG. It is a sequence diagram which shows the operation | movement procedure of a system in case a gateway apparatus implements the operation | movement (1) of FIG. It is a flowchart which shows the characteristic operation | movement (2) of the gateway apparatus contained in the communication system shown in FIG. It is a sequence diagram which shows the operation | movement procedure of a system in case a gateway apparatus implements the operation | movement (2) of FIG. FIG. 5 is a schematic diagram illustrating a specific example of a SIP message transferred when the gateway device performs the operation (2) of FIG. 4 and the determination operation of the gateway device. It is a sequence diagram which shows the example of transmission operation | movement of the ringing tone in the general communication system (1) which mutually connected the some network. It is a sequence diagram which shows the example of transmission operation | movement of the ringing tone in the general communication system (2) which mutually connected the some network. It is a sequence diagram which shows the example of transmission operation | movement of the ringing tone in the general communication system (3) which mutually connected the some network. It is a sequence diagram which shows the specific example in case a trouble arises in provision of a ringing tone in the general communication system which mutually connected the some network.

Embodiments of the present invention will be described below with reference to the drawings.
<Outline of configuration and operation of communication system>
<Description of configuration>
FIG. 1 shows an outline of the configuration and operation of a communication system including a ring tone providing apparatus according to an embodiment of the present invention. The communication system shown in FIG. 1 includes a calling terminal 11, a calling side network 10, a gateway (GW) device 30, a called side network 20, and a called terminal 21. Further, the gateway device 30 includes an RBT sound source 31 and a ringing tone transmission control unit 32.

  Each of the calling terminal 11 and the receiving terminal 21 is a terminal corresponding to, for example, a fixed telephone that is a fixed terminal, a mobile phone that is a mobile phone terminal, a smartphone, or the like, and has a voice call function. In the example shown in FIG. 1, the calling terminal 11 that is a fixed terminal is connected to the calling side network 10, and the called terminal 21 that is a mobile phone terminal is connected to the called side network 20.

  In this example, it is assumed that the calling side network 10 and the called side network 20 are owned or managed by different communication carriers. Therefore, these are interconnected using the gateway device 30 so that communication is possible between the originating network 10 and the terminating network 20 that are independent of each other. The gateway device 30 shown in FIG. 1 is assumed to be deployed as part of the equipment of the originating network 10, but the gateway device 30 may be deployed as part of the equipment of the terminating network 20. .

  The gateway device 30 shown in FIG. 1 has the function of the ringing tone providing device of the present invention. Further, an RBT sound source 31 is connected to the gateway device 30. The RBT sound source 31 is a device that generates a ring tone RBT indicating that a call is being made on the called side, for example, a signal corresponding to a sound such as “Pururu ...”.

  Each part of the communication system shown in FIG. 1 is configured as an IP (Internet Protocol) network. Each of the calling side network 10 and the called side network 20 has a function for providing a VoIP (Voice over Internet Protocol) communication service. As described above, when the IP networks are directly connected to each other without going through the public switched network (PSTN), there is a possibility that the problem as shown in FIG. 10 occurs when the ringing tone RBT is provided. Therefore, in order to avoid the problem, the gateway device 30 has the function of the ringing tone providing device.

<Description of operation>
When the user of the calling terminal 11 performs a calling operation of the calling terminal 11 in order to make a call with the user of the called terminal 21, the sequence shown in FIG. 1 is executed in a predetermined procedure. That is, using the session establishment protocol SIP, a communication path for making a call between the calling terminal 11 and the called terminal 21 is established, and then the call is started. A series of sequences shown in FIG. 1 shows a call operation before a communication path is established.

  When the user of the calling terminal 11 performs a calling operation for calling the called terminal 21, the calling terminal 11 sends a SIP request “INVITE with SDP (no offer, no precondition)” in the first sequence Q1. To send. The originating network 10 relays this request “INVITE with SDP (no offer, no precondition)” to the gateway device 30 in sequence Q2.

  When the gateway device 30 receives the request from the calling terminal 11 via the calling side network 10, it sends the request “INVITE with SDP (offer) in sequence Q3 toward the called side network 20 to which the called terminal 21 is connected. , No precondition) ”. The destination network 20 relays the request “INVITE with SDP (no offer, precondition)” in sequence Q4 to the destination terminal 21 corresponding to the telephone number specified by the received request. As a result, the destination terminal 21 receives the request “INVITE with SDP (no offer, no precondition)” from the source terminal 11.

  In response to the received request, the destination terminal 21 sends an SIP response “183 with SDP (answer)” indicating that the call is being made to the destination network 20 in sequence Q5. The destination network 20 relays this response “183 with SDP (answer)” to the gateway device 30 in sequence Q6.

  When the gateway device 30 receives a response from the called terminal 21 via the called side network 20, the gateway device 30 sends a response “183 with SDP (answer)” toward the calling side network 10 in sequence Q7. The originating network 10 relays this response “183 with SDP (answer)” to the originating terminal 11 in sequence Q8. As a result, the calling terminal 11 receives the response “183 with SDP (answer)” from the called terminal 21.

  Further, as a characteristic control, when receiving the response of sequence Q6 from the destination network 20, the gateway device 30 determines whether or not it is necessary to send out the ring tone RBT in the next sequence Q9. If necessary, the ringing tone RBT generated by the RBT sound source 31 is sent as a media packet from the gateway device 30 to the originating network 10 in the next sequence Q10 if necessary. The media packet of the ring tone RBT is delivered to the calling terminal 11 via the calling side network 10. Therefore, the calling terminal 11 can reproduce the received media packet as sound and output the ringing tone RBT so that the user can hear it.

  In sequence Q9, the gateway device 30 determines whether or not a media packet flows from the direction of the destination network 20 when the response “183 with SDP (answer)” is received. There are a plurality of types of specific determination methods, and any one of the plurality of types is used. Details of the determination method will be described later.

  In the operation shown in FIG. 1, the destination terminal 21 sends a response “180 without SDP” to the destination side network 20 in sequence Q11. This response means that the destination terminal 21 is calling. The destination network 20 relays this response “180 without SDP” to the gateway device 30 in sequence Q12.

  When the gateway device 30 receives the response of the sequence Q12 via the destination network 20, the gateway device 30 sends a response “180 without SDP” to the source network 10 in the sequence Q13. The originating network 10 relays this response “180 without SDP” to the originating terminal 11 in sequence Q14. As a result, the calling terminal 11 receives the response “180 without SDP” from the called terminal 21.

  However, the calling terminal 11 recognizes that a media packet is sent in advance by the response “183 with SDP (answer)” received in sequence Q8. Then, the calling terminal 11 receives the media packet of the ringing tone RBT delivered in sequence Q10, reproduces this ringing tone RBT as sound through a speaker (not shown), and provides it to the user.

  In the communication system shown in FIG. 1, the calling terminal 11 can provide the user with the ringing tone RBT using the media packet of the ringing tone RBT received by the calling terminal 11 in sequence Q10. However, if the gateway device 30 does not perform special control, the result is the same as the operation shown in FIG. 10, and the calling terminal 11 cannot reproduce the ringing tone RBT as sound. That is, the gateway device 30 can control the sequences Q9 and Q10 of FIG. 1 to avoid the occurrence of a problem and provide the ringing tone RBT to the user of the calling terminal 11.

<Explanation of operation details>
<Operation example (1)>
FIG. 2 shows a characteristic operation (1) of the gateway device 30 included in the communication system shown in FIG. FIG. 3 shows an operation procedure of the system when the gateway device 30 performs the operation (1) of FIG.

The operation of the gateway device 30 when executing the control of FIG. 2 will be described below.
When receiving the “18x” response with SDP from the destination network 20, the gateway device 30 proceeds from step S11 to step S12 in FIG. Here, the “18x” response means “180 Ringing” indicating that the call is in progress, “181 Call Is Being Forwarded” indicating that the call is being transferred, “182 Queued” indicating that the process is waiting, and “183 Session” indicating that the session has progressed. Any of “Progress”. Then, the gateway device 30 starts measuring the elapsed time Tx using the internal timer, and then proceeds to the next step S13.

  The gateway device 30 monitors the media packet coming from the destination network 20 in step S13. When the media packet reception is detected, the process proceeds from step S14 to step S15. When the media packet is not received, the process proceeds from step S14 to step S17.

  In step S15, the gateway device 30 transfers the media packet received from the destination network 20 to the source network 10 as it is. Further, the gateway device 30 identifies in step S16 whether or not the termination condition for the ringing tone transmission is satisfied, and continues the processing in step S15 until the termination condition is satisfied.

  In step S17, the gateway device 30 compares the elapsed time Tx from the time when step S12 was executed with a threshold value Tw having a predetermined time length. When the elapsed time Tx exceeds the threshold value Tw, that is, when a timeout is detected, Proceed to step S18. If the elapsed time Tx is within the threshold value Tw, the process returns from step S17 to step S13 and the same processing is repeated. As a specific example of the threshold value Tw, a value of about 1 to 5 seconds is assumed, but this value can be changed as necessary.

  In step S <b> 18, the gateway device 30 sends the media packet of the ring tone RBT generated by the RBT sound source 31 toward the originating network 10 within itself. In step S19, the gateway device 30 identifies whether or not a termination condition for sending a ringing tone is satisfied, and continues the process of step S18 until this termination condition is satisfied. For example, when the communication path between the calling terminal 11 and the called terminal 21 is successfully established, or when the calling terminal 11 cancels the call, the calling sound transmission end condition is satisfied.

  Also in the operation shown in FIG. 3, the sequences Q2, Q3, Q6, and Q7 are executed in the same manner as the operation shown in FIG. Then, in sequence Q9a shown in FIG. 3, gateway device 30 executes the processing shown in FIG.

  That is, in the sequence Q9a, the gateway device 30 monitors the presence / absence of a media packet coming from the destination network 20 over a certain monitoring period. That is, the gateway device 30 monitors the presence / absence of a media packet in step S13 of FIG. 2 over a monitoring period having a length corresponding to the threshold value Tw shown in FIG.

  When receiving the media packet from the destination network 20, the gateway device 30 transfers the media packet as it is to the source network 10 in step S15. If the gateway device 30 does not receive a media packet from the destination network 20 during the monitoring period, the gateway device 30 generates a ring tone RBT in step S18. Accordingly, the media packet of the ring tone RBT is transmitted from the gateway device 30 in the sequence Q10 of FIG.

<Operation example (2)>
FIG. 4 shows a characteristic operation (2) of the gateway device 30 included in the communication system shown in FIG. FIG. 5 shows an operation procedure of the system when the gateway device 30 performs the operation (2) of FIG.

The operation of the gateway device 30 when executing the control of FIG. 4 will be described below.
When receiving the “18x” response with SDP from the destination network 20, the gateway device 30 proceeds from step S21 to step S22 in FIG. Then, the gateway device 30 determines whether or not it is necessary to send its own ring tone RBT based on the SDP header or SDP information included in the received response.

  If the gateway device 30 determines that “transmission is required” in step S22, the process proceeds from step S23 to step S24. Then, the gateway device 30 sends the ringing tone RBT media packet generated by the internal RBT sound source 31 toward the originating network 10. The gateway device 30 identifies in step S25 whether or not the termination condition for sending the ringing tone is satisfied, and continues the processing in step S24 until this termination condition is satisfied. For example, when the communication path between the calling terminal 11 and the called terminal 21 is successfully established, or when the calling terminal 11 cancels the call, the calling sound transmission end condition is satisfied.

  If the gateway device 30 determines that “transmission is not required” in step S22, a media packet of the ringing tone RBT may be input from the destination network 20 side. When the media packet of the ring tone RBT is input, the gateway device 30 transfers the input media packet as it is toward the originating network 10 as in step S15 shown in FIG.

  In the operation shown in FIG. 5 as well, the sequences Q2, Q3, Q6, and Q7 are executed as in the operation shown in FIG. Then, in sequence Q9b shown in FIG. 5, gateway device 30 executes the process shown in FIG.

  That is, in sequence Q9b, gateway device 30 executes step S22 of FIG. 4, and based on the content of the SIP header or SDP information of response “183 with SDP (answer)” received in the immediately preceding sequence Q6. Determines whether or not it is necessary to send the ring tone RBT.

  The gateway device 30 executes step S24 in FIG. 4 when it is determined that “RBT transmission is required” in the sequence Q9b. Therefore, the media packet of the ring tone RBT generated by the RBT sound source 31 in the sequence Q10 shown in FIG. Is sent to the originating network 10.

<Specific example of determination method in operation example (2)>
A specific example of the SIP message transferred when the gateway device 30 performs the operation (2) of FIG. 4 and the determination operation of the gateway device 30 are shown in FIG.

  As in the communication system shown in FIG. 1, when a plurality of carriers' networks are interconnected and the communication path between the calling terminal 11 and the called terminal 21 is established using SIP, the current SIP With the standard specification alone, information necessary for determination by the sequence Q9b shown in FIG. 5 cannot be obtained. Therefore, in order to realize the sequence Q9b, it is necessary to make a new agreement in advance between operators of the originating network 10 and the terminating network 20 and add a special communication specification.

  The SIP message 40 shown in FIG. 6 includes information that embodies the special communication specifications described above. The SIP message 40 in FIG. 6 is sent from the destination network 20 in sequence Q20 and is input to the gateway device 30. This sequence Q20 corresponds to the sequence Q6 in FIG.

  The SIP message 40 shown in FIG. 6 is a response “183 with SDP (answer)” transferred in sequence Q20. The SIP message 40 includes a header part 41 and a body part (SDP) 42 as shown in FIG.

  The header part 41 of the SIP message 40 shown in FIG. 6 includes a description “P-Early-Media: sendonly” as the P early media header designation line 43. The communication system can use the P early media header designation line 43 as one of new arrangements for controlling the ring back tone RBT. For example, when there is an intention to send the ring tone RBT as early media to the destination network 20, the destination network 20 or the destination terminal 21 sends a SIP message 40 including a P early media header designation line 43 in the header portion 41. Send it out. On the other hand, when there is no intention to send the ring tone RBT as early media to the destination network 20, the P early media header designation line 43 is not described in the header section 41.

  When the above arrangement of the P early media header designation line 43 is adopted, the gateway device 30 executes the processing of [judgment example 1] shown in FIG. 6 in step S22 in FIG. 4 and sequence Q9b in FIG. . That is, the gateway device 30 determines whether or not the P early media header designation line 43 exists in the header portion 41 of the SIP message 40 of the response received from the destination network 20. If the P early media header designation line 43 exists, it is determined that there is an intention to provide the ringing tone RBT to the destination network 20. When the P early media header designation line 43 does not exist, it is determined that the gateway device 30 itself needs to generate the ring tone RBT.

  On the other hand, the body part (SDP) 42 of the SIP message 40 shown in FIG. 6 includes a description “a = content: g.3gpp.cat” as a CAT designation line 44. Here, “3gpp.cat” means “Customized Alerting Tones”. The communication system can use this CAT designation line 44 as one of the new arrangements for controlling the ring back tone RBT. For example, when there is an intention to send the ring tone RBT as early media to the destination side network 20, the destination side network 20 or the destination terminal 21 includes the SIP message 40 including the CAT designation line 44 in the body part (SDP) 42. Send it out. On the other hand, when there is no intention to send the ring tone RBT as early media to the destination network 20, the CAT designation line 44 is not described in the body part (SDP).

  When the above arrangement of the CAT designation line 44 is adopted, the gateway device 30 executes the processing of [judgment example 2] shown in FIG. 6 in step S22 of FIG. 4 and sequence Q9b of FIG. That is, the gateway device 30 determines whether or not the CAT designation line 44 exists in the body part (SDP) 42 of the response SIP message 40 received from the destination network 20. If the CAT designation line 44 exists, it is determined that there is an intention to provide a CAT (Customized Alerting Tones), that is, a ringing tone RBT, to the destination network 20. When the CAT designation line 44 does not exist, it is determined that the gateway device 30 itself needs to generate the ring tone RBT.

  Therefore, when the arrangement of the P early media header designation line 43 or the CAT designation line 44 as described above is made in advance, the response received by the gateway device 30 in the sequence Q6 shown in FIG. 5 is shown in FIG. Information such as the SIP message 40 is included. Therefore, when the gateway device 30 executes the sequence Q9b of FIG. 5, information necessary for [Judgment Example 1] or [Judgment Example 2] of FIG.

  Actually, any one of [Judgment Example 1] and [Judgment Example 2] in FIG. 6 may be adopted as necessary and agreed between the operators. Further, the gateway device 30 may control the ringing tone RBT by an arrangement other than the P early media header designation line 43 and the CAT designation line 44 shown in FIG.

<Operation example other than the above: operation example (3)>
For example, in the communication system shown in FIG. 1, whether or not the media packet of the ringing tone RBT flows from the destination network 20 to the gateway device 30 in sequence Q6 depends on the characteristics of the destination terminal 21 itself and the destination terminal 21. It is determined by the characteristics of the destination network 20 managed by the telecommunications carrier contracted by the user. Therefore, when the gateway device 30 determines whether or not RBT transmission is necessary in the sequence Q9 of FIG. 1, if specific information indicating the characteristics of the corresponding receiving terminal 21 is known, the RBT transmission necessity is determined for each receiving terminal 21. It can be estimated in advance.

  Specifically, whether or not the destination network 20 to which the corresponding destination terminal 21 is connected sends a media packet of the ringing tone RBT to the gateway device 30 in association with the telephone number for each destination terminal 21. A database in which a list of information Dx to be represented is registered in advance is prepared. And this database is installed in the location which the gateway apparatus 30 can refer. In this case, the gateway device 30 can obtain the corresponding information Dx by referring to the database from the telephone number of the called terminal 21 in sequence Q9 in FIG. Therefore, based on the content of the acquired information Dx, gateway device 30 can immediately determine whether or not RBT transmission is necessary in sequence Q9 of FIG.

<Advantages of ringing tone providing device>
The gateway device 30 included in the communication system shown in FIG. 1 has a function of “ringing tone providing device”. That is, the gateway device 30 includes an RBT sound source 31 that generates a ringing tone and a ringing tone transmission control unit 32. The ringing tone transmission control unit 32 performs the control shown in FIG. 2 or the control shown in FIG. 4 to determine whether or not the ringing tone needs to be transmitted. A ringing tone RBT is transmitted toward. Therefore, it is possible to avoid a silent state during the calling of the called terminal 84, such as the state of the calling terminal 83 in the communication system shown in FIG. In addition, it is not necessary to make major modifications to the terminals and devices in the network. Therefore, when a plurality of networks are interconnected between different operators, the cost for connection can be reduced, and the time required for connection work can be shortened.

  Further, if the gateway device 30 is always in a state of transmitting the ringing tone RBT, as shown in FIG. 8, when the destination side network 62 transmits the ringing tone RBT, the ringing tone RBT transmitted by the destination side network 62 and The ringing tone RBT transmitted from the gateway device 30 overlaps. However, the gateway device 30 shown in FIG. 1 determines whether or not the ringing tone needs to be transmitted, and when the ringing tone needs to be transmitted, the gateway device 30 transmits the ringing tone RBT toward the calling terminal 11. The situation where duplicates are sent out does not occur.

  Further, when the gateway device 30 determines whether or not the ringing tone needs to be transmitted, when the control shown in FIG. 2 is performed, the media of the ringing tone RBT actually flowing is directly monitored. Even in a situation where there is a mismatch between the agreement between the parties and the actual network operation, it is possible to avoid a malfunction.

  Further, when the gateway device 30 determines whether or not it is necessary to send a ringing tone, it is not necessary to monitor the actual media flow when the control shown in FIG. The waiting time until it can be shortened.

  Further, when the gateway device 30 determines whether or not the ringing tone needs to be transmitted, it is not necessary to monitor the actual media flow even when using a predetermined database holding information on the called terminal 21. Thus, the waiting time until the transmission of the ring tone RBT can be shortened.

  Further, when the gateway device 30 recognizes that the ringing tone transmission is unnecessary, for example, the media packet input from the destination side network 20 in step S15 in FIG. 2 is sent to the source side network 10 as it is. The ringing tone RBT transmitted from 20 can also be used effectively. For example, when a predetermined melody or the like is used for the ring tone RBT in the destination network 20, this melody can be sent to the calling terminal 11 as it is.

10, 51, 61, 71, 81 Originating network 11, 53, 63, 73, 83 Originating terminal 20, 52, 62, 82 Terminating network 21, 54, 64, 84 Terminating terminal 30 Gateway (GW) equipment 31 RBT Sound source 32 Ringing tone transmission control unit 40 SIP message 41 Header unit 42 Body unit (SDP)
43 P early media header designation line 44 CAT designation line 72 PSTN
RBT ringer

Claims (7)

Installed in a gateway that interconnects the first network to which the calling terminal is connected and the second network to which the called terminal is connected, and the call of the calling terminal causes the calling terminal and the called terminal to A ringing tone providing apparatus for providing a predetermined ringing sound indicating that the calling terminal is being called to the calling terminal before establishing a communication path between the calling terminal and
A ring tone generator for generating a ring tone;
Before establishing a communication path between the calling terminal and the called terminal by a call of the calling terminal, it is determined whether or not a ringing tone needs to be sent from the ringing tone generation unit, and when a ringing tone needs to be sent Is a ringing tone transmission control unit that transmits a ringing tone from the ringing tone generation unit to the calling terminal;
A ringing tone providing apparatus. The ringing tone transmission control unit monitors the presence / absence of a media packet input from the second network after receiving a predetermined response from the second network in response to a communication path establishment request, and within a predetermined time If no media packet is detected, it is determined that ringing is necessary.
The ring tone providing apparatus according to claim 1. When the ringing tone transmission control unit receives a predetermined response from the second network in response to the communication path establishment request, the ringing tone transmission control unit determines whether the ringing tone generation unit To determine whether it is necessary to send
The ring tone providing apparatus according to claim 1. The ringing tone transmission control unit receives the predetermined response from the second network in response to the communication path establishment request, based on the content of a predetermined database that holds information about the called terminal. Determining whether it is necessary to send a ring tone from the ring tone generator;
The ring tone providing apparatus according to claim 1. The response is any one of SIP (Session Initiation Protocol) 180 response, 181 response, 182 response, and 183 response.
The ringing tone providing apparatus according to claim 3 or 4. The ringing tone transmission control unit transfers a media packet input from the second network to the first network when recognizing that the ringing tone transmission from the ringing tone generation unit is unnecessary.
The ring tone providing apparatus according to claim 1. A communication system including a first network to which the calling terminal is connected, a second network to which the called terminal is connected, and a gateway that interconnects the two is controlled, and the call is made by the call of the calling terminal. A ringing tone providing method for providing a predetermined ringing sound indicating that the calling terminal is being called to the calling terminal before establishing a communication path between the terminal and the called terminal. ,
Before establishing a communication path between the calling terminal and the called terminal by a call of the calling terminal, the gateway determines whether or not a ringing tone needs to be transmitted. Sending the generated ringing tone toward the calling terminal;
A method for providing a ringing tone.

Images