KR100849759B1

KR100849759B1 - Method for providing a ring-back tone in a wcdma network

Info

Publication number: KR100849759B1
Application number: KR20070035344A
Authority: KR
Inventors: 최창빈
Original assignee: 엘지노텔 주식회사
Priority date: 2007-04-11
Filing date: 2007-04-11
Publication date: 2008-07-31

Abstract

A method for providing a ring-back tone in a WCDMA network is provided to prevent unnecessary transcoding for a ring-back tone transmitted to a calling terminal in calling a called terminal belonging to a WCDMA MSC, in which a ring-back service is registered, thereby providing a ring-back tone of good quality. A method for providing a ring-back tone in a WCDMA(Wideband Code Division Multiple Access) network comprises the following steps of: allowing a calling terminal to attempt a call to a called terminal belonging to an MSC(Mobile Switching Center)(110) on the WCDMA network; allowing the calling terminal to perform signaling between a ring-back tone server(120) and the MSC to set a bearer connection section between the ring-back tone server and the MSC when the called terminal is registered in a ring-back tone service; activating a TFO(Tandem Free Operation) function for exchanging codec information respectively in the ring-back tone server and the MSC; transceiving a TFO message through the set bearer connection section between transcoders included respectively in the ring-back tone server and the MSC to perform codec negotiation; and allowing the ring-back tone server to transmit an encoded ring-back tone without additional transcoding to the calling terminal through the MSC when it is checked that the same codec is supported.

Description

METHOD FOR PROVIDING A RING-BACK TONE IN A WCDMA NETWORK}

1 is a diagram showing the configuration of a WCDMA Mobile Switching Center (MSC) system according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a transcoding process using a Tandem Free Operation (TFO) function in the WCDMA MSC system shown in FIG.

110: WCMA MSC

120: ringback tone server

130: outgoing network

140: called terminal

150: calling terminal

160: transcoder

170: Node B

180: RNC (Radio Network Controller)

The present invention relates to a ring-back tone providing method in a wideband code division multiple access (WCDMA) communication network.

In the recent mobile communication service, when attempting to make a call to the other party's terminal, a so-called ringback tone service (eg, domestic mobile) that provides sound source data such as music or sound effects designated by the subscriber of the called terminal to the calling terminal instead of the general basic ringback tone. Among telecom operators, SK Telecom's coloring services and KTF's ring-to-yu services are being implemented. The ring back tone service may be provided in a WCDMA network, which is a third generation communication network. This is not only when the called terminal belongs to the same WCDMA network, but also when the called terminal belongs to a heterogeneous network. The present invention may also be applied to a conventional second generation network or a case belonging to a public switched telephone network (PSTN).

In the conventional ringback tone service, when an originating subscriber attempts to call a ringing subscriber (ringback service subscriber) of a WCDMA mobile switching center (MSC), the WCDMA MSC may send the ringback tone to the calling subscriber. It must be connected to the ringback tone server. To this end, signaling for establishing a bearer connection interval between the WCDMA MSC and the ringback tone server must be performed. In general, signaling between a WCDMA MSC and a ringback tone server is performed by using an ISDN User Part (ISP), and a bearer is connected to a PCM interval based on time-division multiplexing (TDM). In the signaling process using ISUP, IAM (Initial Address Message) and ACM (Address Complete Message) are exchanged between ring backtone server and WCDMA MSC, and between WCDMA MSC and originating subscriber network. The call progress message (CPG) is delivered to the calling network.

As such, when a bearer connection interval is established between the WCDMA MSC and the ringback tone server, transcoding is performed to change the coding scheme of the ringback tone stored in the ringback tone server to be compatible with the transmission network to which the ringback tone is transmitted. do. If the calling subscriber is a subscriber of the WCDMA network, transcoding between the adaptive multi-rate (AMR) codec commonly used in the WCDMA network and the PCM (Pulse Code Modulation) codec mainly used for storing sound in the ringback tone server It is performed by a transcoder included in the vocoder of the WCDMA MSC. If the originating subscriber is a subscriber of 2nd generation network or PSTN network, two vocoders included in WCDMA MSC and ringback tone server are used for transcoding between PCM codec and AMR codec for codec compatibility between 2nd generation / PSTN network and WCDMA network. Since transcoding between the AMR codec and the PCM codec is necessary for codec compatibility between the ringback tone server and the WCDMA network, a total of two transcodings are performed.

As described above, when the calling subscriber attempts to call a called subscriber (ringback service subscriber) of a specific WCDMA MSC, the calling subscriber belongs to the ringback tone transmitted from the ringback tone server to the calling subscriber through the incoming WCDMA network. Transcoding was performed to change the coding method irrespective of the type, and in particular, when the type of the network is different, transcoding is repeatedly performed in both the WCDMA MSC and the ringback tone server, resulting in ringback tone sound quality. It leads to the problem of deterioration.

It is an object of the present invention to provide a method for delivering ringback tones of improved sound quality in a WCDMA communication network.

Another object of the present invention is to transmit a good ringback tone by avoiding unnecessary transcoding by using a TFO (Tandem Free Operation) function when transmitting a ringback tone from a ringback tone server to an originating terminal through an incoming WCDMA MSC. To provide a way.

According to one embodiment of the present invention, a method for providing a ringback tone in a WCDMA network is provided. When a call is attempted from a calling terminal to a called terminal belonging to an MSC of the WCDMA network, when the called terminal is registered in a ringback tone service, signaling is performed between a ringback tone server for providing a ringback tone to the calling terminal and the MSC. A bearer connection interval is established between the ring back tone server and the MSC. After the TFO function for exchanging codec information in the ringback tone server and the MSC is activated, the codec is transmitted and received through the set bearer connection interval between the ringback tone server and the transcoder included in the MSC. Carry out negotiations. If it is confirmed that the same codec can be supported as a result of the codec negotiation, the ringback tone is transmitted from the ringback tone server to the calling terminal through the MSC without additional transcoding.

According to another embodiment of the present invention, signaling between the MSC and the ringback tone server is made through an ISUP.

According to another embodiment of the present invention, the bearer is delivered through a PCM interval based on TDM.

According to another embodiment of the present invention, when the calling terminal belongs to the same MSC as the called terminal or the WCDMA network, the codec is an AMR codec.

According to another embodiment of the present invention, when the calling terminal belongs to the second generation network or the PSTN, the codec is a PCM codec.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings. However, it will be apparent that these embodiments may be practiced without some or all of the specific details. In other words, well known procedural steps or elements have not been described in detail in order to avoid unnecessarily obscuring in describing exemplary embodiments of the present invention.

1 is a diagram schematically illustrating a configuration of a WCDMA MSC system according to an embodiment. The called terminal 140 is connected to the WCDMA MSC 110 through the Node B 170 and the RNC 180, and the WCDMA MSC 110 transmits the ringback tone to the calling terminal 150 through the PCM section. It is connected to the ringback tone server 120. WCDMA MSC 110 includes transcoder 160 for codec conversion. The calling terminal 150 belongs to the calling network 130, and the calling network 130 may be the same as the WCDMA network to which the called terminal 140 belongs or a conventional second generation network or a public switched telephone network (PSTN). .

Looking at the process of providing a ringback tone service in the system shown in Figure 1 as follows. When the calling terminal 150 belonging to the calling network 130 attempts to make a call to the called terminal 140 registered in the ringback tone service, signaling is performed between the ringback tone server 120 and the WCDMA MSC 110. The bearer connection interval is set to the PCM interval. When the ringback tone server 120 and the WCDMA MSC 110 are connected through a bearer connection interval, codec negotiation between the WCDMA MSC 110 and the ringback tone server 120 is performed by a Tandem Free Operation (TFO). Is performed using the function.

As a result of the negotiation, if a ringback tone corresponding to the codec is determined, information on the ringback tone is stored in the ringback tone server 120, and then the ringback tone is transmitted through the WCDMA MSC 110 without transcoding. Therefore, unlike the prior art in which the transcoding for unconditionally changing the coding scheme is performed on the ringback tone transmitted from the ringback tone server to the calling subscriber via the incoming WCDMA network, regardless of the type of the network to which the calling subscriber belongs, the ringback tone Since duplicate transcoding does not occur in the server 120 and the WCMA MSC 110, a high quality ringback tone may be provided to the calling terminal 150 without degrading sound quality.

Here, the TFO function is a standard derived from the Global System for Mobile Communication (GSM), which is used in the second generation GSM and the third generation UMTS (WCDMA). The TFO function transmits and receives codec information on the in-band call path between the two systems in the GSM or UMTS system so that the voice quality is reduced by not transcoding in each system. Speak function to improve. Therefore, the third generation network (or GSM) is applied only to the third generation network in which the ringback tone server is interlocked, and the second generation network (or PSTN) and the ringback tone server are not linked to the network. Therefore, in the above embodiment, in order to achieve the object of the present invention, it is preferable to apply the above-described TFO function to both the WCDMA MSC 110 and the ringback tone server 120.

FIG. 2 illustrates in more detail a transcoding process using a Tandem Free Operation (TFO) function in the WCDMA MSC system shown in FIG. 1. As described above, when a call is attempted from the calling terminal 150 to the called terminal 140 belonging to the WCDMA MSC 110, if the called terminal 140 is registered in the ringback tone service, a ringback tone is sent to the calling terminal 150. WCDMA MSC 110 must be connected to ringback tone server 120 to provide it. To this end, a bearer connection interval is established between the WCDMA MSC 110 and the ringback tone server 120 through signaling. The signaling between the WCDMA MSC 110 and the ringback tone server 120 is performed through an ISUP, and the bearer Is preferably connected to a PCM interval based on TDM. As shown in FIG. 2, in the signaling process using ISUP, IAM and ACM are exchanged between the ringback tone server and the WCDMA MSC, and between the WCDMA MSC and the originating network to which the calling subscriber belongs, and the callback is transmitted from the ringback tone server via the WCDMA MSC. CPG is delivered to the network.

If a bearer connection interval is established between the WCDMA MSC and the ringback tone server through this process, the TFO function is activated in each of the WCDMA MSC 110 and the ringback tone server 120. In the case where both TFO functions are provided, a codec negotiation procedure is performed between each other, which includes a TFO message (TFO_REQ and TFO_ACK in FIG. 2) between the transcoder provided in the ringback tone server 120 and the WCDMA MSC 110, respectively. Is transmitted and received). If codec negotiation confirms that the same codec can be supported, bearer delivery is possible without transcoding. If the calling terminal 150 belongs to the own station or the same WCDMA network, the codec negotiation result will be the AMR codec since the default codec is the AMR codec. Therefore, the ringback tone server 120 transmits the ringback tone encoded by the AMR codec, and the WCDMA MSC 110 can transmit the ringback tone to the calling terminal 150 without transcoding, so that the sound quality due to transcoding The fall can be prevented.

On the other hand, if the calling terminal 150 belongs to a second generation network or another network such as a PSTN, the result of the codec negotiation will be the PCM codec. Therefore, the ringback tone server 120 transmits a ringback tone encoded by the PCM codec. In addition, the WCDMA MSC 110 can transmit the ringback tone to the calling terminal 150 without transcoding, thereby preventing sound quality degradation due to transcoding.

According to the present invention, when a ringback tone service attempts to make a call to a called terminal belonging to a registered WCDMA MSC, it is possible to provide an effective ringback tone because unnecessary transcoding is not performed on the ringback tone transmitted to the calling terminal. Can be.

Claims

A method for providing ringback tone in a WCDMA network,

Attempting a call from a calling terminal to a called terminal belonging to an MSC of the WCDMA network;

When the called terminal is registered with a ringback tone service, establishing a bearer connection interval between the ringback tone server and the MSC by performing signaling between a ringback tone server for providing a ringback tone to the calling terminal and the MSC; ;

Activating a TFO function for exchanging codec information at the ring back tone server and the MSC, respectively;

Performing codec negotiation by transmitting and receiving a TFO message between the ringback tone server and a transcoder included in the MSC through the set bearer connection interval; And

If it is determined that the same codec can be supported as a result of the codec negotiation, transmitting the encoded ringback tone without additional transcoding from the ringback tone server to the calling terminal through the MSC,

The bearer is delivered through a PCM interval based on TDM, ringback tone providing method.

The method of claim 1,

The signaling between the MSC and the ringback tone server is performed through ISUP.

delete

The method of claim 1,

If the calling terminal belongs to the same MSC as the called terminal or to the WCDMA network, the same codec is an AMR codec.

The method of claim 1,

If the originating terminal belongs to a second generation network or a PSTN, the same codec is a PCM codec.