KR100374035B1 - Method for transmitting tone signal for voice over internet protocol system - Google Patents

Abstract

The present invention provides a method for minimizing loss or misrecognition of DTMF information while ensuring real-time when transmitting DTMF signals in a VOIP system. The method of the present invention for transmitting a DTMF signal in a VOIP system that transmits voice data through an RTP channel using a UDP public port, DTDT transmission port and DTMF using a predetermined UDP transmission port and UDP receiving port Set up the receiving port to prepare for DTMF transmission. After the VOIP call setup is completed according to the VOIP call request and the voice channel is allocated, when the DTMF signal is detected, the DTMF information message indicating the digit information of the detected DTMF signal is transmitted using UDP as the DTMF receiving port of the receiving VOIP system. send. When the receiving side receives the DTMF information message indicating the digit information through the DTMF receiving port, a DTMF signal corresponding to the digit information of the received DTMF information message is generated and sent to the receiving subscriber.

Description

Tone signal transmission method in voice over internet protocol system {METHOD FOR TRANSMITTING TONE SIGNAL FOR VOICE OVER INTERNET PROTOCOL SYSTEM}

The present invention relates to a Voice Over Internet Protocol (VOIP) system, and more particularly to a method of transmitting a tone signal.

VOIP is a core technology that enables Internet telephony. It uses IP (Internet Protocol) to transmit not only data but also voice through the Internet.

The configuration of a VOIP network for transmitting data and voice over the Internet using the VOIP is shown in FIG. 1. 1 shows an example in which two VOIP systems 102 and 104 transmit / receive data and voice over the Internet 100 using VOIP. A subscriber telephone 104 is connected to one VOIP system 102. In addition, the VOIP system 106 shows an example in which not only the subscriber phone 108 but also a system 110 such as an audio response system (ARS), a voice mailing system (VMS), a computer telephony integration (CTI), and the like are connected to the subscriber phone 108. .

In the VOIP systems 102 and 106 of FIG. 1, when call setup according to a VOIP call request is completed, actual voice data of a subscriber is transmitted through a Real Time Transfer (RTP) channel. At this time, the voice signal input from the subscriber is converted into PCM (Pulse Code Modulation) data, and the converted voice data is compressed and packetized by a compression method according to G711, G723.1, G729, and the like. The RTP channel used here uses UDP (User Datagram Protocol) ports using well-known ports recommended by H.323 and other standardization protocols.

However, unlike TCP / IP (Transmission Control Protocol / Internet Protocol), which communicates after establishing a connection with a partner prior to transmission, UDP checks the actual data for errors and attempts to retry. Do not take As a result, UDP is faster than TCP / IP, but data is less reliable.

Due to the characteristics of the Internet, the data transmitted through UDP may be reversed in sequence according to the delay or traffic amount of the network according to the transmission path, and may be lost during transmission. In this case, it is very difficult to recover because no retry is attempted. However, even when a small packet is lost or the sequence is reversed in voice data transmission, the data is analyzed before and after the corresponding packet to generate the voice data of the intermediate value, so that a human can understand. In addition, since the most demanded voice data transmission is real time, the voice data transmission in the VOIP uses a UDP port.

On the other hand, after the VOIP call setup is completed between the VOIP systems 102 and 106, the user of the subscriber telephone 104 presses the button of the telephone 104 to enter the extension number into the ARS / VMS / CTI system 110 or enters the social security number. In some cases, the authentication process may be required. In this case, the dual tone multi-frequency (DTMF) signal according to the digit information input by the user is passed through the VOIP system 102 and the ARS / VMS / CTI system through the Internet 100 and the VOIP system 106. 110).

At this time, since the ARS / VMS / CTI system 110 must accurately recognize the digit information according to the DTMF signal, accuracy is required unlike the voice signal. Despite this, if DTMF is transmitted with voice on a real network such as the Internet, that is, if it is transmitted through UDP port that compresses and divides into multiple packets and transmits voice data like voice data, DTMF also transmits packets. This may be lost or modulated differently when the packet sequence is restored as it is lost.

When the above phenomenon occurs, the false recognition rate of DTMF is increased in the ARS / VMS / CTI system 110 interworking with the VOIP system 106 on the destination side, and a normal call cannot be performed. That is, the DTMF according to the extension number or social security number input by the user is lost or tampered with and misrecognized by the ARS / VMS / CTI system 110 is a factor that prevents further call progress.

Meanwhile, according to the H.323 protocol established by the International Telecommunication Union-Telecommunication Standardization Sector (ITU-T), a TCP transmission method using an H.245 port is recommended as a method of transmitting DTMF. Therefore, if a packet carrying DTMF data is lost or a data fail occurs, retransmission is required. This can reduce DTMF's misperception, but it can be a factor that hinders real-time. However, the transmission of DTMF signals is as important as voice data.

As described above, if the VOIP system compresses and transmits information requiring accuracy such as DTMF signal through the RTP channel using UDP as voice data, its reliability is lowered, and when the TCP transmission scheme is adopted to improve the reliability, Real-time performance will be impaired. As a result, the VOIP system has a problem of interworking with a system such as ARS / VMS / CTI on a real network such as the Internet.

Accordingly, an object of the present invention is to provide a method for minimizing loss or misrecognition of DTMF information while guaranteeing real time when transmitting DTMF signals in a VOIP system.

1 is a typical VOIP network configuration,

2 is a configuration diagram of a software task according to an embodiment of the present invention;

3 is a process flow diagram in accordance with an embodiment of the present invention.

The method of the present invention for achieving the above object is a method for transmitting a DTMF signal in a VOIP system for transmitting voice data through an RTP channel using a UDP public port, DTMF using a predetermined UDP transmission port and UDP receiving port Set the sending port and DTMF receiving port to prepare for DTMF transmission. After the VOIP call setup is completed according to the VOIP call request and the voice channel is allocated, when a DTMF signal is detected from the signal to be transmitted, a DTMF information message indicating the digit information of the detected DTMF signal is transmitted to the DTMF receiving port of the receiving VOIP system. Send using. When the receiving side VOIP system receives the DTMF information message indicating the digit information through the DTMF receiving port, a DTMF signal corresponding to the digit information of the DTMF information message is generated and sent to the receiving subscriber.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description and the annexed drawings, detailed descriptions of well-known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted.

As described above, processing data transmission requiring accuracy such as DTMF together with voice causes problems such as misrecognition and data loss. In order to solve this problem, the present invention transmits a more stable network path in the case of information requiring accuracy and real time, such as DTMF. That is, in the VOIP system, another UDP public port is set separately from voice data using the UDP public port defined in the standardization protocol, and is used as a dedicated transmission path for DTMF data. To do this, first, an independent path must be set to send and receive DTMF information to each VOIP system, and an independent task to control DTMF data is required. Such tasks are referred to as DTMF sending tasks and DTMF receiving tasks in the present invention.

FIG. 2 illustrates a software task configuration diagram according to an embodiment of the present invention with respect to FIG. 1 as described above. The task configuration of each of the VOIP systems 102 and 106 shows only the tasks necessary for the description of the present invention. Figure 2 also illustrates the signal flow between tasks in the case of transmitting voice and DTMF information from telephone 104 to telephone 108 via VOIP system 102 and the Internet 100 and VOIP system 106. Showed. Accordingly, in the VOIP system 102, the digital signal processor (DSP) manager task 200, the voice packet processing task 204, the H.323 main control task 206, and the DTMF transmission task 208 were shown. 106) shows the DSP task 216, voice packet processing task 212, H.323 main control task 214 and DTMF receive task 210. If the transmission direction is reversed as shown in FIG. 2, the VOIP system 102 becomes like the VOIP system 106 while the VOIP system 106 becomes like the VOIP system 102. In addition, in an actual application in which the VOIP systems 102 and 106 transmit bidirectionally to each other, each of the VOIP systems 102 and 106 may have both a DTMF transmission task and a DTMF reception task.

Referring now to Figure 3, which shows a process flow diagram according to an embodiment of the present invention in steps 300 and 310, the VOIP system 102, 106 generates a DTMF transmit / receive task in step 300 at initialization. A DTMF transmission / reception port is prepared by opening a socket using a predetermined UDP transmission / reception port and setting a DTMF transmission / reception port. At this time, the UDP transmit / receive port sets a predetermined private port. The DSP manager tasks 200 and 216 prepare to exchange messages with the DTMF sending task 208 and the DTMF receiving task 210, respectively. Here, the DTMF send / receive task means a DTMF send task and a DTMF receive task. Likewise, a UDP send / receive port means a UDP send port and a UDP receive port, and a DTMF send / receive port means a DTMF send port and a DTMF receive port.

Thereafter, when the VOIP call setup is completed according to the VOIP call request in step 302 and the voice channel is allocated, voice data is transmitted between the VOIP systems 102 and 106 shown in FIG. 1. In this state, for example, as shown in FIG. 2, a DTMF signal is generated from the telephone 104 and input to the VOIP system 102. The DTMF signal is detected by the DSP manager task 200. As such, when the DTMF signal is detected from the signal to be transmitted to the counterpart, in step 304, the DSP manager task 200 sends the information about the H.323 main control task 206 through the internal message (IPC: Interprocess Communication). Is sent to the DTMF send task 208. Then, in step 306, the DTMF transmission task 208 transmits a DTMF information message indicating the digit information of the detected DTMF signal to the DTMF receiving port of the receiving VOIP system 106 by using UDP. At this time, the DTMF transmission task 208 creates and transmits one DTMF information message for each digit detected by the DSP manager task 200.

In the VOIP system 106 that receives the DTMF information message transmitted from the VOIP system 102 as described above, the process proceeds from step 304 to step 308 to indicate the DTMF information message indicating the digit information to the DTMF receiving port. In step 310, a DTMF signal corresponding to the digit information of the DTMF information message is generated and transmitted to the receiving subscriber 108 in step 310. At this time, the DTMF receiving task 210 analyzes the message received through the corresponding UDP receiving port and transmits it to the DSP manager task 216 if it is digit information so that a DTMF signal corresponding thereto is generated. At this time, a voice RTP channel, that is, a UDP port for transmitting voice data, receives a DTMF signal processed like a voice as in the prior art.

Therefore, in the related art, voice data and DTMF data are all transmitted using one UDP port. However, in the present invention, DTMF data itself is transmitted while using a separate UDP dedicated port different from the UDP port for transmitting voice data. Instead, the message indicating the digit information is transmitted, and the receiving side generates a DTMF signal according to the digit information of the received message. In this case, since the DTMF signal corresponding to one digit is transmitted as one message rather than being divided into several packets as in the related art, loss of DTMF data can be minimized because the packet loss rate is lowered.

Therefore, the method of transmitting using UDP is the same as voice data transmission, but the accuracy is much higher because it is transmitted as UDP packet instead of the actual DTMF signal, which is converted into a message indicating the digit information according to the DTMF signal, and recommended by ITU-T. Unlike DTMF transmission using TCP, real-time performance is not impaired.

Meanwhile, in the above description of the present invention, specific embodiments have been described, but various modifications can be made without departing from the scope of the present invention. In particular, in the embodiment of the present invention, as well as transmitting and receiving DTMF signals in one VOIP system as an example, the transmission and reception may be applied separately. Therefore, the scope of the invention should not be defined by the described embodiments, but should be defined by the equivalent of claims and claims.

As described above, the present invention replaces the DTMF signal with a message indicating the digit information according to the DTMF signal and transmits the UDP packet using a separate UDP port instead of the UDP port for transmitting voice data. At the same time, there is an advantage in that it is possible to obtain an effect that guarantees real time.

Claims (9)

In a method for transmitting a DTMF signal in a VOIP system for transmitting voice data through an RTP channel using a UDP public port, Preparing a DTMF transmission by setting a DTMF transmission port and a DTMF reception port using a predetermined UDP transmission port and a UDP reception port; After the VOIP call setup is completed according to the VOIP call request and the voice channel is allocated, when a DTMF signal is detected from the signal to be transmitted, a DTMF information message indicating the digit information of the detected DTMF signal is transmitted to the DTMF receiving port of the receiving VOIP system. Tone signal transmission method comprising the step of transmitting using. The method of claim 1, wherein the DTMF preparation process is performed. Generating a DTMF receiving task for creating and transmitting the DTMF information message, a DTMF receiving task for confirming digit information of the DTMF information message by analyzing a message received through the DTMF receiving port; And the DTMF transmitting task and the DTMF receiving task are configured to open the socket by setting the DTMF transmitting port and the DTMF receiving port using the UDP port. The tone signal transmission method according to claim 1, wherein the DTMF transmission port and the DTMF reception port are set to a separate UDP dedicated port different from the UDP public port for transmitting the voice data. In a method for transmitting a DTMF signal in a VOIP system for transmitting voice data through an RTP channel using a UDP public port, Preparing a DTMF transmission by setting a DTMF transmission port and a DTMF reception port using a predetermined UDP transmission port and a UDP reception port; After receiving the DTMF information message indicating the digit information from the DTMF receiving port in the state where the VOIP call setup is completed according to the VOIP call request, the DTMF signal corresponding to the digit information of the received DTMF information message is generated to the receiving subscriber. Tone signal transmission method comprising the step of transmitting. The method of claim 4, wherein the DTMF transmission preparation process, Generating a DTMF receiving task for creating and transmitting the DTMF information message, a DTMF receiving task for confirming digit information of the DTMF information message by analyzing a message received through the DTMF receiving port; And the DTMF transmitting task and the DTMF receiving task are configured to open the socket by setting the DTMF transmitting port and the DTMF receiving port using the UDP port. 5. The tone signal transmission method according to claim 4, wherein the DTMF transmission port and the DTMF reception port are set to a separate UDP dedicated port different from the UDP public port for transmitting the voice data. In a method for transmitting a DTMF signal in a VOIP system for transmitting voice data through an RTP channel using a UDP public port, Preparing a DTMF transmission by setting a DTMF transmission port and a DTMF reception port using a predetermined UDP transmission port and a UDP reception port; After the VOIP call setup is completed according to the VOIP call request and the voice channel is allocated, when a DTMF signal is detected from the signal to be transmitted, a DTMF information message indicating the digit information of the detected DTMF signal is transmitted to the DTMF receiving port of the receiving VOIP system. Using the transmission process, And receiving a DTMF information message indicating digit information from the DTMF receiving port, generating a DTMF signal corresponding to the digit information of the received DTMF information message, and transmitting the DTMF signal to a receiving subscriber. Way. The method of claim 7, wherein the DTMF transmission preparation process, Generating a DTMF receiving task for creating and transmitting the DTMF information message, a DTMF receiving task for confirming digit information of the DTMF information message by analyzing a message received through the DTMF receiving port; And the DTMF transmitting task and the DTMF receiving task are configured to open the socket by setting the DTMF transmitting port and the DTMF receiving port using the UDP port. 8. The tone signal transmission method according to claim 7, wherein the DTMF transmission port and the DTMF reception port are set to a UDP dedicated port separate from the UDP public port for transmitting the voice data.