WO2005122542A1

WO2005122542A1 - Method and system for providing ringback tones

Info

Publication number: WO2005122542A1
Application number: PCT/IB2005/001593
Authority: WO
Inventors: Steve Hazelwood
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2004-06-07
Filing date: 2005-06-06
Publication date: 2005-12-22

Abstract

A system and method in a telecommunications network for providing audible ringback tones to a calling party while the calling party waits for a called party to answer a call. A Service Switching Point, SSP, (11) establishes a temporary connection with an Intelligent Peripheral, IP, (14) which provides the ringback tones to the calling party utilizing the temporary connection. A Service Control Point, SCP, (12) then instructs the SSP to initiate call setup to the called party. The SSP then obtains a roaming number for the called party from a Mobile Switching Center/Visitor Location Register, MSC/VLR, (15) where the called party is operating, and utilizes the roaming number to establish a call connection between the SSP and the MSC/VLR. When it is determined that the called party has answered the call, the temporary connection between the SSP and the IP is released, and the calling and called parties are connected to the SSP.

Description

METHOD AND SYSTEM FOR PROVIDING RINGBACK TONES

TECHNICAL FIELD OF THE INVENTION The present invention relates to digital wireless communication systems. More particularly, and not by way of limitation, the present invention is directed to a method and system for providing the audible ringback tones presented to a calling party while the calling party waits for a called party to answer the call.

DESCRIPTION OF RELATED ART Ringback tones are the audio sounds heard by a calling party while waiting for a connection to a called party to be completed. An Intelligent

Peripheral (IP) associated with one of the switches serving the called party, a switch serving the calling party, or an intermediate switch may generate the audible ringing tone. In existing standards and procedures, there has not been a defined multi-vendor call-control procedure defining how ringback tones are to be provided in an openly defined network. Some manufacturers have utilized proprietary protocols to interface a manufacturer-specific switch and an IP, or have utilized undesirable procedures in which a first connection is made to the

IP, and the IP dials out another connection for playing the ringback tones. Such procedures are undesirable because of the network resources required. In order to eliminate the requirement to set up two connections with the IP, an Intelligent Network solution has been proposed. However, there are no standardized multi-vendor call-control procedures for providing ringback tones in the context of an Intelligent Network. The following protocol abbreviations are utilized herein: CAP V2 CAMEL Application Part Version 2 ISUP ISDN User Part MAP Mobile Application Part BICC Bearer Independent Call Control DSS1 Digital Subscriber Signalling 1 The following network node abbreviations are utilized herein: SSP Service Switching Point SCP Service Control Point MSC Mobile Switching Centre HLR Home Location Register IP Intelligent Peripheral The following MAP protocol abbreviations are utilized herein: SRI Send Routing Information PRN Provide Roaming Number TCSI Terminating CAMEL Service Information The following CAP_V2 protocol abbreviations are utilized herein: IDP Initial Detection Point RRB Request Report BCSM Event [see GSM TS 03.78] ETC Establish Temporary Connection ARI Assist Request Instructions [see GSM TS 03.78] CTR Connect to Resource PA Play Announcement ERB Event Report BCSM CUE Continue DFC Disconnect Forward Connection SRR Specialized Resource Request The following ISUP protocol abbreviations are utilized herein: 1AM Initial Address Message ACM Address Complete Message ANM Answer Message REL Release RLC Release Complete

SUMMARY OF THE INVENTION In one aspect, the present invention is directed to a method in a telecommunications network for providing audible ringback tones to a calling party while the calling party waits for a called party to answer a call. The method includes initiating the call from the calling party to the called party; establishing a temporary connection between a gateway switch and an Intelligent Peripheral (IP); and providing by the IP, audible ringback tones to the calling party utilizing the temporary connection. A Service Control Point (SCP) then instructs the gateway switch to initiate call setup to the called party. The gateway switch then obtains a roaming number for the called party from a terminating switch where the called party is operating, and utilizes the roaming number to establish a call connection between the gateway switch and the terminating switch. When it is determined that the called party has answered the call, the temporary connection between the gateway switch and the IP is released, and a connection is provided between the calling party and the called party. In another aspect, the present invention is directed to a system for providing audible ringback tones to a calling party while the calling party waits for a called party to answer a call. The system includes an IP for generating the audible ringback tones, a gateway switch, and an SCP in communication with the gateway switch. The gateway switch includes means for establishing a temporary connection with the IP, wherein the audible ringback tones are provided by the IP to the calling party utilizing the temporary connection; and means for performing call setup from the calling party to the called party. The

SCP includes service logic for instructing the gateway switch to initiate call setup to the called party; service logic for instructing the gateway switch to establish the temporary connection with the IP; service logic for instructing the IP to play the audible ringback tone; service logic for instructing the gateway switch to release the temporary connection with the IP upon determining that the called party has answered the call; and service logic for instructing the gateway switch to connect the calling party and the called party after the temporary connection with the IP has been released. In other aspects, the present invention provides ringback tones and call control procedures when events affecting the procedures occur. For example, the present invention provides ringback tones and call control procedures when the connection to the IP cannot be established. The invention also provides ringback tones and call control procedures when the connection to the IP is initially established, but is released due to an IP failure before the called party answers. If the calling party disconnects before the called party answers, the invention provides ringback tones until the disconnection, and provides call control procedures for tearing down the call thereafter.

BRIEF DESCRIPTION OF THE DRAWINGS The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself however, as well as preferred modes of use, further objects and advantages thereof, will best be understood by reference to the following detailed description of illustrative embodiments when read in conjunction with the accompanying drawings, wherein: Figure 1 is a simplified block diagram illustrating a network configuration and supported interworking protocols, in accordance with a preferred embodiment of the system of the present invention; Figure 2 is a signaling diagram illustrating signaling messages sent between network nodes when providing a successful ringback tone call according to a preferred embodiment of the method of the present invention; Figure 3 is a signaling diagram illustrating signaling messages sent between network nodes when providing a ringback tone call in accordance with the present invention, and a connection to an Intelligent Peripheral (IP) cannot be established; Figure 4 is a signaling diagram illustrating signaling messages sent between network nodes when providing a ringback tone call in accordance with the present invention, and the connection to the IP is released before the called party answers; and Figure 5 is a signaling diagram illustrating signaling messages sent between network nodes when providing a ringback tone call in accordance with the present invention, and the calling party disconnects before the called party answers. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS In the following description, for purposes of explanation and not limitation, specific details are set forth such as particular architectures, interfaces, techniques, etc. in order to provide a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. In other instances detailed descriptions of well-known devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail. Figure 1 is a simplified block diagram illustrating a network configuration and supported interworking protocols, in accordance with a preferred embodiment of the system of the present invention. A Service Switching Point (SSP) 1 1 serves as a gateway for the network. A Service Control Point (SCP) 12 provides intelligent network services, and a Home Location Register (HLR) 13 provides subscriber profile information and subscriber location information. An Intelligent Peripheral (IP) 14 provides ringback tones to the calling party. A Mobile Switching Center/Visitor Location Register (MSCΛ LR) 15 provides terminating switching services for the called party. The interface between the SSP and the SCP (CAP_V2+) utilizes CAP_V2 as the base protocol with enhancements that enable the functionality described below. Figure 2 is a signaling diagram illustrating signaling messages sent between network nodes when providing a successful ringback tone call according to a preferred embodiment of the method of the present invention. The calling party is referred to herein as the A-party, and the called party is referred to as the B-party. An incoming call to the SSP 1 1 causes the SSP 12 to send a Send Routing Information (SRI) message to the HLR 13. This triggers a Terminating CAMEL Service Information (TCSI) operation and an Initial Detection Point (IDP) operation to the SCP 12. The SCP requests the SSP to monitor events (B-Answer, A-Abandon, B-Busy, and B-NoAnswer) with one or more Request Report BCSM Event (RRB) operations (one RRB may be used to arm multiple events). The SCP sends an Establish Temporary Connection (ETC) operation to the SSP to establish a connection from the SSP to the IP 14. This ETC operation has an indication that "Bothway Path" is not required because this prevents the start of charging the call up to the SSP. The SSP 11 then establishes an ISUP connection to the IP 14 (IAM, ACM, and ANM messages). The IP requests instructions from the SCP using, for example, an Assist Request Instructions (ARI) operation, and the SCP instructs the IP to play the corresponding ringback tone using a Play Announcement (PA) operation. Alternatively, the SCP 12 may send either a ETC operation or a Connect to Resource (CTR) operation to the SSP 11 to establish a connection from the

SSP to the IP 14 or another mechanism in the network capable of generating ringback tones. When the connection is made to the IP or other mechanism, the ringback tones are automatically generated, and the ARI and PA operations are not required. The SCP 12 then initiates a call to the original called party by sending a

Continue (CUE) operation to the SSP 11. This sequence is illegal according to the CAP_V2 protocol, and under existing call flow procedures, the SSP would reject the CUE operation, causing the call setup to fail. In the present invention, however, enhancements to the CAP_V2 protocol cause the CUE operation to trigger the SSP to perform additional call-setup functions. First, the SSP sends an SRI message to the HLR 13 with a "Suppress TCSI" parameter in order to suppress TCSI in the HLR for this interrogation. This causes the HLR to send a Provide Roaming Number (PRN) operation to the MSC/VLR 15. The MSC/VLR returns the roaming information to the HLR, and the HLR sends the roaming information to the SSP in an SRI-ack message. When the SSP receives the roaming information, the SSP establishes an ISUP connection from the SSP to the MSC/VLR (IAM and ACM messages). When the called party answers, an ANM message is sent over the ISUP connection to the SSP, which reports the event in an Event Report BCSM (ERB) operation to the SCP 12. The SCP orders the release of the connection from the SSP 11 to the IP 14 with a

Disconnect Forward Connection (DFC) operation. The SSP then releases the ISUP connection to the IP (REL and RLC), thus stopping the ringback tones. The SCP orders a cancellation of event monitoring with a CAN operation, and then orders a reconnection of the calling and called parties to the SSP using another CUE operation. Figure 3 is a signaling diagram illustrating signaling messages sent between network nodes when providing a ringback tone call in accordance with the present invention, and a connection to the IP cannot be established. An incoming call to the SSP 1^*1 causes the SSP to send an SRI message to the HLR 13. This triggers a TCSI operation and an IDP operation to the SCP 12. The SCP requests the SSP to monitor events (B-Answer, A-Abandon, B-Busy, and B-NoAnswer) with one or more RRB operations (one RRB may be used to arm multiple events). The SCP sends an ETC operation to the SSP to establish a connection from the SSP to the IP 14. This ETC operation has an indication that "Bothway Path" is not required because this prevents the start of charging the call up to the SSP. The SSP attempts to establish an ISUP connection to the

IP, but in this example, the connection is released (IAM and REL). The present invention recognizes this event and in response, reverts to legacy ringback procedures. The SSP reports the failure event to the SCP using an ETC "Error" indication (ETCFailed), and the SCP orders a cancellation of event monitoring with a CAN operation. The SCP then orders normal call processing by sending a CUE operation to the SSP. The SSP sends an SRI to the HLR 13 with a "Suppress TCSI" parameter in order to suppress TCSI in the HLR for this interrogation. This causes the HLR to send a PRN operation to the MSC/VLR 15. The MSCVLR returns the roaming information to the HLR, and the HLR sends the roaming information to the SSP in an SRI-ack message. When the SSP receives the roaming information, the SSP establishes an ISUP connection from the SSP to the MSC/VLR (IAM and ACM messages). The MSCΛ LR begins providing ringback tones to the calling party. When the called party answers, the MSC/VLR sends an ANM message over the ISUP connection to the SSP, and the calling and called parties are connected. Figure 4 is a signaling diagram illustrating signaling messages sent between network nodes when providing a ringback tone call in accordance with the present invention, and the connection to the IP is released before the called party answers. An incoming call to the SSP 11 causes the SSP to send an SRI message to the HLR 13. This triggers a TCSI operation and an I DP operation to the SCP 12. The SCP requests the SSP to monitor events (B-Answer, A- Abandon, B-Busy, and B-NoAnswer) with one or more RRB operations (one RRB may be used to arm multiple events). The SCP sends an ETC operation to the SSP to establish a connection from the SSP to the IP 14. This ETC operation has an indication that "Bothway Path" is not required because this prevents the start of charging the call up to the SSP. The SSP then establishes an ISUP connection to the IP (IAM, ACM, and ANM messages), and the IP plays the corresponding ringback tone using operations ARI and PA. The SCP then initiates a call to the original called party using a CUE operation. This sequence is illegal according to the CAP_V2 protocol, and under existing call flow procedures, the SSP would reject the CUE operation, causing the call setup to fail. In the present invention, however, the CUE operation triggers the SSP to perform additional call-setup functions. First, the SSP sends an SRI to the HLR 13 with a "Suppress TCSi" parameter in order to suppress TCSI in the HLR for this interrogation. This causes the HLR to send a PRN operation to the MSC/VLR 15. The MSC/VLR returns the roaming information to the HLR, and the HLR sends the roaming information to the SSP in an SRI-ack message. When the SSP receives the roaming information, the SSP establishes an ISUP connection from the SSP to the MSC/VLR (IAM and ACM messages). In this example, an error then occurs in the IP 14, which sends a PA

"Error" indication to the SCP 12 indicating the error. This error may occur earlier in the sequence since the PA operation is sent during the process of connecting to the IP. When the ISUP connection with the MSCΛ LR 15 is established, the announcement has already been playing for some time, so if there is a problem with executing PA in the IP, the error may be reported earlier. This error could be caused by a hardware failure, missing translations, or a resource shortage. In response, the SCP sends a DFC operation to the SSP to order the release of the connection from the SSP 11 to the IP. The SSP then releases the ISUP connection to the IP (REL and RLC). The SCP then orders a cancellation of event monitoring with a CAN operation, and orders normal call processing by sending a CUE operation to the SSP. In response, the SSP establishes the call to the MSC/VLR, which begins providing ringback tones to the calling party. When the called party answers, an ANM message is sent over the ISUP connection to the SSP. The MSCΛ LR stops sending the ringback tones to the calling party, and the calling and called parties are connected. Figure 5 is a signaling diagram illustrating signaling messages sent between network nodes when providing a ringback tone call in accordance with the present invention, and the calling party disconnects before the called party answers. An incoming call to the SSP 11 causes the SSP to send an SRI message to the HLR 13. This triggers a TCSI operation and an IDP operation to the SCP 12. The SCP requests the SSP to monitor events (B-Answer, A-

Abandon, B-Busy, and B-NoAnswer) with one or more RRB operations (one RRB may be used to arm multiple events). The SCP sends an ETC operation to the SSP to establish a connection from the SSP to the IP 14. This ETC operation has an indication that "Bothway Path" is not required because this prevents the start of charging the call up to the SSP. The SSP then establishes an ISUP connection to the IP (IAM, ACM, and ANM messages), and the IP plays the corresponding ringback tone using operations ARI and PA. The SCP then initiates a call to the original called party using a CUE operation. This sequence is illegal according to the CAP_V2 protocol, and under existing call flow procedures, the SSP would reject the CUE operation, causing the call setup to fail. In the present invention, however, the CUE operation triggers the SSP to perform additional call-setup functions. First, the SSP sends an SRI to the HLR 13 with a "Suppress TCSI" parameter in order to suppress TCSI in the HLR for this interrogation. This causes the HLR to send a PRN operation to the MSC/VLR 15. The MSC/VLR returns the roaming information to the HLR, and the HLR sends the roaming information to the SSP in an SRI-ack message. When the SSP receives the roaming information, the SSP establishes an ISUP connection from the SSP to the MSC/VLR (IAM and ACM messages). In this example, the calling party disconnects at this point, which causes the SSP 11 to report the event in an ERB operation to the SCP 12. The SSP then releases the IP connection (REL and RLC). This leads to a predefined call disconnection procedure in which the SSP then releases the ISUP connection to the MSC/VLR (REL and RLC). The present invention may of course, be carried out in other specific ways than those herein set forth without departing from the essential characteristics of the invention. For example, instead of using an IP to generate the ringback tones as described above, an operator may also utilize another playing mechanism in the network to generate audible ringback tones. The SSP may generate ringback tones utilizing an integrated gsmSRF (Specialized Resource Function). Using an external gsmSRF, a connection may be established between the SSP and an external gsmSRF using ISUP or DSS1. The IP may also be utilized with external gsmSRF. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.

Claims

CLAIMS:

1. In a telecommunications network, a method of providing audible ringback tones to a calling party while the calling party waits for a called party to answer a call, said method comprising: initiating the call from the calling party to the called party; establishing a temporary connection between a gateway switch (11) and an Intelligent Peripheral, IP (14); providing by the IP, audible ringback tones to the calling party utilizing the temporary connection; sending a message from a Service Control Point, SCP, (12) to the gateway switch, instructing the gateway switch to initiate call setup to the called party; obtaining by the gateway switch (11), a roaming number for the called party from a terminating switch (15) where the called party is operating; utilizing the roaming number to establish a call connection between the gateway switch (11) and the terminating switch (15); determining that the called party has answered the call; releasing the temporary connection between the gateway switch (11) and the IP (14); and providing a connection between the calling party and the called party.

2. The method of claim 1 , wherein the step of providing audible ringback tones to the calling party includes providing the ringback tones by the IP utilizing Assist Request Instructions, ARI, and Play Announcement, PA, operations.

3. The method of claim 1 , wherein the step of providing audible ringback tones to the calling party includes automatically providing the ringback tones by the IP when the temporary connection is established.

4. The method of claim 1 , wherein the step of obtaining a roaming number for the called party includes the steps of: sending by the gateway switch, a Send Routing Information, SRI, message to the called party's Home Location Register, HLR, (13) wherein the SRI message includes a parameter causing the HLR to suppress Terminating

CAMEL Service Information, TCSI, operation in the HLR; sending a Provide Roaming Number, PRN, message from the HLR to the terminating switch; sending the roaming number for the called party from the terminating switch to the HLR; and sending the roaming number from the HLR to the gateway switch.

5. The method of claim 4, wherein the step of determining that the called party has answered the call includes the steps of: sending an answer message from the terminating switch to the gateway switch; and sending from the gateway switch to the SCP, a report that the called party has answered.

6. The method of claim 5, wherein the step of releasing the temporary connection between the gateway switch and the IP includes the steps of: sending a release instruction from the SCP to the gateway switch; and in response to the release instruction, releasing the temporary connection between the gateway switch and the IP, thus stopping the ringback tones.

7. The method of claim 6, wherein the step of sending a release instruction from the SCP to the gateway switch includes sending a Disconnect Forward Connection, DFC, message from the SCP to the gateway switch.

8. The method of claim 1 , wherein the step of providing a connection between the calling party and the called party includes the steps of: sending a message from the SCP to the gateway switch ordering a cancellation of event monitoring; and providing the connection between the calling party and the called party by sending a Continue message to the gateway switch.

9. In a telecommunications network, a method of providing audible ringback tones to a calling party while the calling party waits for a called party to answer a call, said method comprising: initiating the call from the calling party to the called party; attempting to establish a temporary connection between a gateway switch (11) and an Intelligent Peripheral, IP (14); determining that the temporary connection between the gateway switch (11) and the IP (14) cannot be established; and completing call setup utilizing legacy ringback procedures.

10. The method of claim 9, wherein the step of completing call setup utilizing legacy ringback procedures includes the steps of: sending an error report from the gateway switch (11) to a Service Control

Point, SCP (12), reporting that the temporary connection between the gateway switch and the IP could not be established; initiating a call to the called party by the SCP (12), by sending a Continue message to the gateway switch (11); obtaining by the gateway switch (11), a roaming number for the called party from a terminating switch (15) where the called party is operating; utilizing the roaming number to establish a call connection between the gateway switch (11 ) and the terminating switch (15); providing legacy ringback tones to the calling party by the terminating switch (15); determining that the called party has answered the call; ceasing to provide legacy ringback tones to the calling party by the terminating switch (15); and providing a connection between the calling party and the called party.

1 1. In a telecommunications network, a method of providing audible ringback tones to a calling party while the calling party waits for a called party to answer a call, said method comprising: initiating the call from the calling party to the called party; establishing a temporary connection between a gateway switch (1 1) and an Intelligent Peripheral, IP (14); providing by the IP (14), audible ringback tones to the calling party utilizing the temporary connection; initiating a call to the called party by a Service Control Point, SCP (12), by sending a Continue message to the gateway switch; obtaining by the gateway switch (1 1), a roaming number for the called party from a terminating switch (15) where the called party is operating; utilizing the roaming number to establish a call connection between the gateway switch (11) and the terminating switch (15); determining before the called party answers, that an error has occurred in the IP (14) causing the audible ringback tones to fail; sending an error report from the gateway switch (1 1) to the SCP (12), reporting that the IP has failed; releasing the temporary connection between the gateway switch (1 1) and the IP (14); sending a message from the SCP (12) to the gateway switch (11), instructing the gateway switch to continue call setup; providing a connection between the calling party and the called party; providing legacy ringback tones to the calling party by the terminating switch (15); determining that the called party has answered the call; and ceasing to provide legacy ringback tones to the calling party by the terminating switch (15).

12. In a telecommunications network, a method of providing audible ringback tones to a calling party while the calling party waits for a called party to answer a call, said method comprising: initiating the call from the calling party to the called party; establishing a temporary connection between a gateway switch (1 1 ) and an Intelligent Peripheral, IP (14); providing by the IP (14), audible ringback tones to the calling party utilizing the temporary connection; initiating a call to the called party by a Service Control Point, SCP (12), by sending a Continue message to the gateway switch (1 1 ); obtaining by the gateway switch (1 1), a roaming number for the called party from a terminating switch (15) where the called party is operating; utilizing the roaming number to establish a call connection between the gateway switch (11 ) and the terminating switch (15); determining that the calling party has abandoned the call; sending a report from the gateway switch (1 1) to the SCP (12), reporting that the calling party has abandoned the call; releasing the temporary connection between the gateway switch (1 1) and the IP (14); and releasing the call connection between the gateway switch (11 ) and the terminating switch (15).

13. In a telecommunications network, a system for providing audible ringback tones to a calling party while the calling party waits for a called party to answer a call, said system comprising: an Intelligent Peripheral, IP, (14) for generating the audible ringback tones; a gateway switch (1 1), comprising: means for establishing a temporary connection with the IP, wherein the audible ringback tones are provided by the IP to the calling party utilizing the temporary connection; and means for performing call setup from the calling party to the called party; and a Service Control Point, SCP, (12) in communication with the gateway switch, said SCP including: service logic for instructing the gateway switch (1 1) to initiate call setup to the called party; service logic for instructing the gateway switch (11 ) to establish the temporary connection with the IP (14); service logic for instructing the IP (14) to play an audible ringback tone; service logic for instructing the gateway switch (11) to release the temporary connection with the IP (14) upon determining that the called party has answered the call; and service logic for instructing the gateway switch (1 1) to connect the calling party and the called party after the temporary connection with the IP (14) has been released.

14. In a telecommunications network, a method of providing audible ringback tones to a calling party while the calling party waits for a called party to answer a call, said method comprising: initiating the call from the calling party to the called party; establishing a temporary connection between a gateway switch (11) and a playing mechanism for generating audible ringback tones (14); providing by the playing mechanism, audible ringback tones to the calling party utilizing the temporary connection; sending a message from a Service Control Point, SCP, (12) to the gateway switch, instructing the gateway switch to initiate call setup to the called party; obtaining by the gateway switch (11), a roaming number for the called party from a terminating switch (15) where the called party is operating; utilizing the roaming number to establish a call connection between the gateway switch (11 ) and the terminating switch (15); determining that the called party has answered the call; releasing the temporary connection between the gateway switch (11) and the playing mechanism (14); and providing a connection between the calling party and the called party.

15. The method of claim 14, wherein the step of establishing a temporary connection between the gateway switch and a playing mechanism includes establishing a temporary connection with an external Specialized Resource Function, gsmSRF, using ISUP, BICC, or DSS1 protocol.

16. The method of claim 14, wherein the step of establishing a temporary connection between the gateway switch and a playing mechanism includes establishing a temporary connection with an integrated Specialized Resource Function, gsmSRF, within the gateway switch.