JP7283057B2 - Communication device, communication method and program - Google Patents

Description

The present invention relates to a communication device, communication method and program.

Voice call services based on VoIP (Voice over Internet Protocol) technology often use communication using the RTP (Real Time Transport Protocol) protocol disclosed in Non-Patent Document 1. At that time, in communication (network) through which RTP packets flow, gateway devices are often installed at the boundaries of communication networks such as networks of different types or communication networks between operators to realize packet communication.

Here, in a call service, a DTMF (Dual-Tone Multi-Frequency) signal (see Non-Patent Document 2) is assigned to each push button of a user terminal and used for services such as a call center. For the DTMF signal, one frequency is selected from four types of low group frequencies (697 Hz, 770 Hz, 852 Hz, 941 Hz) and four types of high group frequencies (1209 Hz, 1336 Hz, 1477 Hz, 1633 Hz) and added. is the signal generated by

In various services such as call centers, DTMF signals are treated as "deemed voice". In other words, the DTMF signal is transmitted and received on the network as RTP packets conforming to the RTP protocol (communication by deemed voice RTP packets).

Alternatively, the DTMF signal is one type of RTP packet in which information (digit number, signal level, etc.) related to the DTMF signal described in RFC (Request for Comments) 4733 (see Non-Patent Document 3) is stored in a predetermined field. may be sent and received as

It should be noted that the signal length of the DTMF signal corresponds to the number of RTP packets that are continuously transmitted, regardless of whether the communication is "deemed voice RTP packet communication" or the format according to RFC4733. In "communication using deemed voice RTP packets", one RTP packet may include a plurality of voice frames encoded by the voice encoding method to be used or a plurality of DTMF signal information. In such a case, the DTMF signal length corresponds to the number of encoded speech frames, not the number of RTP packets.

Non-Patent Document 4 discloses RTCP-XR (Real-time Transport Control Protocol-extended report) regarding RTP statistical information and communication quality. Further, Patent Literature 1 discloses a frequency analysis method for determining whether or not an RTP packet contains a DTMF signal.

JP-A-2000-324519

H. Schulzrinne, S. Casner, R. Frederick, V. Jacobson, "RTP: A Transport Protocol for Real-Time Applications", RFC3550, July 2003, [searched on October 25, 2018], Internet <URL: http http://www.ietf.org/rfc/rfc3550.txt> ITU-T "MULTIFREQUENCY PUSH-BUTTON SIGNAL RECEPTION", Q.24, [Searched on October 25, 2018], Internet <URL: https://www.itu.int/rec/T-REC-Q.24 /en> H. Schulzrinne and T. Taylor, "RTP Payload for DTMF Digits, Telephony Tones, and Telephony Signals", RFC4733, December 2006, [searched on October 25, 2018], Internet <URL: http://www.ietf .org/rfc/rfc4733.txt> T. Friedman, R. Caceres, A. Clark, "RTP Control Protocol Extended Reports (RTCP XR)", RFC3611, November 2003, [searched on October 25, 2018], Internet <URL: http://www. ietf.org/rfc/rfc3611.txt>

In addition, each disclosure of the above prior art documents is incorporated into this document by reference. The following analysis was made by the inventors.

As noted above, RTP packets may contain DTMF signals. At that time, if the DTMF signal is transmitted with a sufficiently long signal length (DTMF signal length), the destination device can easily recognize the presence of the signal.

On the other hand, in communication in which DTMF signals are transmitted and received, voice communication is also performed, so it is not preferable to transmit DTMF signals with excessively long signal lengths unless there is a special reason. Also, ITU-T Q.2003 disclosed in Non-Patent Document 2 as a specification for DTMF signals. 24, etc., and there are transmission devices that have strict operating specifications for devices that detect DTMF signals, such as transmission with a signal length close to the lower defined value of the DTMF signal length.

However, due to fluctuations and packet loss due to congestion and failures in the IP (Internet Protocol) communication network through which RTP packets pass, there are situations where it is difficult for the destination device to detect and recognize the specified DTMF signal. there's a possibility that.

For example, consider the network system (communication system) shown in FIG. The network shown in FIG. 2 includes gateway devices 101a and 101b which are provided with communication networks for communicating with user terminals 102 represented by mobile terminals, etc., and which are arranged at connection boundaries with other IP communication networks. be

In the destination gateway device (or the communication device at the destination) that is the destination of the RTP packet shown in FIG. Detection and recognition can be difficult. Therefore, it is conceivable that the gateway device 101a (or the user terminal 102, which is the base point of VoIP communication), which is the transmission source of the RTP packet, executes transmission control. In other words, it is conceivable to execute transmission control aimed at reducing non-detection or erroneous recognition of the DTMF signal at the destination device (for example, the gateway device 101b serving as the destination) due to the influence of the network.

However, it is assumed that the transmission source device cannot recognize the quality of the transmission destination device or the IP communication network beyond it, or the detection status of the DTMF signal at the transmission destination device. It can be difficult to understand the circumstances required for

A main object of the present invention is to provide a communication device, a communication method, and a program that contribute to making it possible to easily confirm the existence of a DTMF signal.

According to the first aspect of the present invention or disclosure, an RTP transmission/reception unit that transmits and receives RTP (Real time Transport Protocol) packets and a communication network that transmits RTP packets determine whether quality deterioration has occurred. and an analysis control unit, wherein the analysis control unit analyzes a dual-tone multi-frequency (DTMF) signal stored in an RTP packet and transmitted/received when it is determined that quality deterioration has occurred in the communication network. A communication device is provided that controls RTP packets to increase the signal length.

According to a second aspect of the present invention or disclosure, in a communication device, a step of transmitting and receiving RTP (Real time Transport Protocol) packets, and determining whether quality deterioration has occurred in a communication network that transmits the RTP packets a step of controlling the RTP packet so that the signal length of the DTMF (Dual-Tone Multi-Frequency) signal stored in the RTP packet and transmitted/received is increased when it is determined that the quality of the communication network is degraded; A method of communication is provided, comprising the steps of:

According to a third aspect of the present invention or disclosure, whether quality deterioration has occurred in the process of transmitting and receiving RTP (Real time Transport Protocol) packets to a computer installed in a communication device and in the communication network that transmits the RTP packets. When it is determined that the quality deterioration has occurred in the communication network, the signal length of the DTMF (Dual-Tone Multi-Frequency) signal stored in the RTP packet and transmitted and received is increased. A program for executing a process of controlling RTP packets is provided.
This program can be recorded in a computer-readable storage medium. The storage medium can be non-transient such as semiconductor memory, hard disk, magnetic recording medium, optical recording medium, and the like. The invention can also be embodied as a computer program product.

According to each aspect of the present invention and disclosure, there are provided a communication device, a communication method, and a program that contribute to making it possible to easily confirm the existence of a DTMF signal.

1 is a diagram for explaining an overview of an embodiment; FIG. 1 is a diagram illustrating an example of a schematic configuration of a communication system according to a first embodiment; FIG. It is a figure which shows an example of the processing structure of the gateway apparatus which concerns on 1st Embodiment. FIG. 10 is a diagram for explaining the conversion operation of the U-Plane data processing unit; FIG. 4 is a diagram for explaining the definition of APP types of RTCP packets; FIG. 4 is a diagram showing an example of information stored in a U-Plane statistical information accumulation unit; 4 is a flow chart showing an example of the operation of the gateway device according to the first embodiment; FIG. 10 is a diagram illustrating an example of a processing configuration of a user terminal according to the second embodiment; FIG. It is a figure which shows an example of the hardware constitutions of a gateway apparatus.

First, an overview of one embodiment will be described. It should be noted that the drawing reference numerals added to this outline are added to each element for convenience as an example to aid understanding, and the description of this outline does not intend any limitation. Also, connecting lines between blocks in each figure include both bi-directional and uni-directional. The unidirectional arrows schematically show the flow of main signals (data) and do not exclude bidirectionality. Furthermore, in the circuit diagrams, block diagrams, internal configuration diagrams, connection diagrams, etc. disclosed in the present application, an input port and an output port exist at the input end and the output end of each connection line, respectively, although not explicitly shown. Input/output interfaces are similar.

A communication device 10 according to one embodiment includes an RTP (Real time Transport Protocol) transmission/reception unit 11 and an analysis control unit 12 (see FIG. 1). The RTP transmission/reception unit 11 transmits and receives RTP packets. The analysis control unit 12 determines whether quality deterioration has occurred in the communication network that transmits the RTP packets. Furthermore, when the analysis control unit 12 determines that quality deterioration has occurred in the communication network, the signal length of the DTMF (Dual-Tone Multi-Frequency) signal stored in the RTP packet and transmitted/received is increased. It controls RTP packets.

For example, the communication device 10 is placed in a VoIP communication environment in which DTMF signals are transmitted and received as RTP packets in "deemed voice" or "RFC4733 format" via an IP communication network. When the communication device 10 analyzes recognition information of DTMF signals and network quality (eg, packet loss rate) in other communication devices (eg, downstream communication devices) and determines that the quality is degraded, It performs transmission control related to RTP packets. For example, the communication device 10 instructs the transmission source device (upstream communication device) of the RTP packet to perform transmission control such as increasing the time length of the DTMF signal when transmitting the RTP packet. Specifically, the communication device 10 instructs the transmission source device to increase the number of RTP packets in which DTMF signals are stored and which are continuously transmitted. Alternatively, the communication device 10 performs a conversion operation to increase the time length of the DTMF signal in an internal module of the communication device 10 and controls transmission of the RTP packet.

In this way, the communication device 10 feeds back information to the transmission source device based on the statistical information indicating the network quality and the authentication information of the DTMF signal in other devices, and prompts the implementation of appropriate transmission control for the RTP packet. . As a result, the RTP packet in which the DTMF signal output by the transmission source device is stored can be reliably transmitted to the downstream communication device.

Specific embodiments will be described in more detail below with reference to the drawings. In addition, the same code|symbol is attached|subjected to the same component in each embodiment, and the description is abbreviate|omitted.

[First Embodiment]
The first embodiment will be described in more detail with reference to the drawings.

FIG. 2 is a diagram illustrating an example of a schematic configuration of a communication system according to the first embodiment; Referring to FIG. 2, the communication system includes two gateway devices 101a and 101b and a user terminal 102. FIG. It is needless to say that FIG. 2 is an example and is not intended to limit the configuration of the system.

The two gateway devices 101a and 101b shown in FIG. 2 each have the same function, and are simply referred to as "gateway device 101" unless there is a particular reason to distinguish them.

FIG. 3 is a diagram showing an example of the processing configuration of the gateway device 101 according to the first embodiment. Referring to FIG. 3, the gateway device 101 includes a call control unit 201, a plurality of U-Plane (User-Plane) processing units 202a to 202n, a U-Plane statistical information storage unit 210, a U-Plane analysis/control and a part 211 . In the following description, the U-Plane processing units 202a to 202n are simply referred to as "U-Plane processing units 202" unless there is a particular reason to distinguish them.

The U-Plane processing unit 202 includes a first RTP transmission/reception unit 203, a first RTCP (Real-time Transport Control Protocol) transmission/reception unit 204, a U-Plane data processing unit 205, a statistical information storage unit 206, It includes an analysis/control unit 207 , a second RTP transmission/reception unit 208 , and a second RTCP transmission/reception unit 209 .

Each of the U-Plane processing units 202a to 202n includes the above units.

The call control unit 201 terminates call control with a higher-level call control device or an opposite communication device. The call control unit 201 performs setting, control, resource management, etc. related to call connection to the subordinate U-Plane processing unit 202 according to the content of the call control so that communication of the call can be performed. Note that FIG. 3 is a configuration example assuming that a plurality of communication sessions can be implemented by the number of U-Plane processing units 202 (a to n).

The U-Plane processing unit 202 performs setting and control for performing U-Plane communication for each functional unit (each processing module) in accordance with instructions from the call control unit 201, and performs U-Plane processing for the call of the target communication. Realize communication.

The first RTP transmission/reception unit 203 transmits/receives RTP packets. Specifically, the first RTP transmission/reception unit 203 transmits/receives the RTP packet of the target call arriving from the IP circuit network. The first RTP transmitting/receiving unit 203 outputs U-Plane data (user data) included in the received RTP packet to the U-Plane data processing unit 205 .

Regarding the reverse direction, the first RTP transmitting/receiving unit 203 configures an RTP packet based on the packet data information acquired from the U-Plane data processing unit 205, and directs the configured RTP packet to the communication device ahead of the IP line. to send.

The first RTP transmission/reception unit 203 calculates statistical information indicating the quality of the communication network (IP line network) from the received RTP packets. For example, the first RTP transmitting/receiving unit 203 calculates packet loss rate, jitter value, etc. as the statistical information. The first RTP transmission/reception unit 203 stores the calculated statistical information in the U-Plane statistical information storage unit 210 .

Furthermore, the first RTP transmission/reception unit 203 calculates statistical information in response to a request from the first RTCP transmission/reception unit 204 . The calculated statistical information is output to the first RTCP transceiver 204 (the first RTP transceiver 203 responds to the request).

In addition, the first RTP transmission/reception unit 203 is information acquired from the first RTCP transmission/reception unit 204, and is RTP statistical information (packet loss rate, jitter value, etc.) included in the RTCP packet transmitted from the opposite device. ) is used to perform RTP transmission/reception control (RTP transmission/reception control of its own device).

The first RTCP transmitting/receiving section 204 transmits/receives RTCP packets of the target communication call. The first RTCP transmitting/receiving unit 204 transfers various statistical information included in the received RTCP packet to the first RTP transmitting/receiving unit 203 . First RTCP transmitting/receiving section 204 outputs control information included in the received RTCP packet to analysis/control section 207 .

The first RTCP transmitting/receiving unit 204 periodically acquires statistical information about RTP from the first RTP transmitting/receiving unit 203, constructs an RTCP packet based on the information, and transmits the RTCP packet. The first RTCP transmitting/receiving unit 204 may construct an RTCP packet in response to information or instructions from the first RTP transmitting/receiving unit 203 or the analysis/control unit 207, and transmit the RTCP packet to the IP network. be.

The U-Plane data processing unit 205 performs predetermined conversion processing on the U-Plane data included in the received RTP packet. Specifically, the U-Plane data processing unit 205 adds the U-Plane data to the setting/control content from the call control unit 201 or the instruction content from the analysis/control unit 207 for the U-Plane data. Convert. The converted data is output to the second RTP transmission/reception section 208 .

Also, the U-Plane data processing unit 205 analyzes the acquired U-Plane data. Specifically, the U-Plane data processing unit 205 analyzes whether the U-Plane data is a DTMF signal. That is, the U-Plane data processing unit 205 determines and analyzes whether or not a DTMF signal is stored in the received RTP packet.

Furthermore, when the U-Plane data processing unit 205 determines that the U-Plane data is a DTMF signal, the U-Plane data processing unit 205 stores the information (the U-Plane data is a DTMF signal) in the statistical information storage unit 206 . That is, the U-Plane data processing unit 205 stores the fact that the DTMF signal has been detected (DTMF signal detection history) in the statistical information storage unit 206 .

The U-Plane data processing unit 205 similarly applies U-Plane data acquired from the second RTP transmission/reception unit 208 to the U-Plane according to the instruction content from the call control unit 201 or the analysis/control unit 207. Predetermined conversion processing is performed on the data. After that, the U-Plane data processing unit 205 outputs the U-Plane data to the first RTP transmitting/receiving unit 203, analyzes whether the U-Plane data in the corresponding direction is a DTMF signal, and determines that the U-Plane data is a DTMF signal. information storage processing.

The statistical information storage unit 206 includes each processing unit (first RTP transmission/reception unit 203, first RTCP transmission/reception unit 204, U-Plane data processing unit 205, second RTP transmission/reception unit 208, second RTCP transmission/reception unit 209 ) (statistical information, information on DTMF signals; DTMF detection history). The statistical information storage unit 206 outputs the information in response to a request from the analysis/control unit 207 .

The analysis/control unit 207 analyzes various information and controls each unit of the U-Plane processing unit 202 . Specifically, the analysis/control unit 207 determines whether quality deterioration has occurred in the communication network that transmits the RTP packets. Furthermore, when the analysis/control unit 207 determines that quality deterioration has occurred in the communication network, it controls the RTP packet so that the signal length of the DTMF signal stored in the RTP packet and transmitted/received is increased.

The analysis/control unit 207 performs analysis based on the statistical information extracted from the statistical information storage unit 206 and the information on the DTMF signal. Based on the analysis result, the analysis/control unit 207 determines whether information notification (information feedback) to the source of the RTP packet is necessary.

As a result of analysis, when it is determined that feedback to the transmission source is necessary, analysis/control section 207 outputs control information to first RTCP transmission/reception section 204 or second RTCP transmission/reception section 209 . Specifically, when the DTMF signal is stored as "deemed voice" based on a combination of predetermined frequencies, the analysis/control unit 207 sends the signal stored in the RTP packet to another communication device (transmission source device). command to lengthen the signal length of the DTMF signal.

Alternatively, as a result of the analysis, when it is determined that the U-Plane data regarding the DTMF signal needs to be converted by the apparatus itself, the analysis/control section 207 outputs a conversion instruction to the U-Plane data processing section 205 . Specifically, when the DTMF signal is stored in the RTP packet in the format of RFC4733, the analysis/control unit instructs the U-Plane data processing unit 205 to extend the signal length of the DTMF signal. Instruct the data to be transformed.

The second RTP transmitter/receiver 208 and the second RTCP transmitter/receiver 209 have the same functions as the first RTP transmitter/receiver 203 and the first RTCP transmitter/receiver 204, respectively. Regarding the description of the second RTP transceiver 208 and the second RTCP transceiver 209, the first RTP transceiver 203 is the second RTP transceiver 208, and the first RTCP transceiver 204 is the second RTCP transceiver. 209, the IP circuit network can be read as the other IP circuit network.

The U-Plane statistical information storage unit 210 stores call information (IP address, UDP (User Datagram Protocol) port number, etc.) acquired from the call control unit 201, RTP statistical information from each of the U-Plane processing units 202a to 202n, DTMF Accumulates signal detection/recognition history. U-Plane statistical information storage unit 210 outputs the accumulated information in response to a request from U-Plane analysis/control unit 211 .

The U-Plane analysis/control unit 211 performs analysis based on the information extracted from the U-Plane statistical information storage unit 210 . Specifically, when the U-Plane analysis/control unit 211 determines that information notification (information feedback) to the transmission source is necessary, at least one of the U-Plane processing units 202a to 202n is controlled. Output instructions.

[Explanation of operation]
Next, the operation of the gateway device according to the first embodiment will be described with reference to FIG. Note that the gateway device 101a in FIG. 2 will be described as the source of the RTP packet, and the gateway device 101b as the destination.

[Operation as destination device (RTP packet receiving device)]
The call control unit 201 of the gateway device 101b receives call information (IP address, UDP port number, voice encoding method to be used, RTP payload type value, etc.) determined by communication with a higher-level call control device or an opposing communication device. ), the U-Plane processing unit 202 is set up and instructed to enable RTP communication.

The U-Plane processing unit 202 realizes desired RTP communication by controlling each function unit included therein (first RTP transmitting/receiving unit 203, etc.) according to the call setup/instruction from the call control unit 201. FIG. For RTP communication, RTP packets arriving from one IP communication network are received by the first RTP transmission/reception unit 203 .

The first RTP transmitting/receiving unit 203 extracts the U-Plane data in the received RTP packet, uses the RTP header information (for example, the RTP sequence number and time stamp described in Non-Patent Document 1) as accompanying information, and converts the U - Hand over to the U-Plane data processing unit 205 together with the Plane data.

The U-Plane data processing unit 205 performs predetermined processing on the U-Plane data and accompanying information according to the call setup contents, and outputs the result to the second RTP transmission/reception unit 208 . The second RTP transmission/reception unit 208 converts the U-Plane data into RTP packets again and outputs them to the other communication network.

Note that the predetermined processing by the U-Plane data processing unit 205 described above corresponds to, for example, transparent transfer in which U-Plane data is transferred without being processed when the input and output are of the same audio encoding method. Alternatively, in the case of audio encoding schemes with different input and output, conversion processing such as decoding U-Plane data and encoding it by another audio encoding scheme corresponds to the predetermined processing.

Also, when receiving an RTP packet in the RFC4733 format, the U-Plane data processing unit 205 transmits RTP header information (for example, payload type value, sequence number, time stamp value, etc.) to the receiving IP communication network and the transmitting IP communication network. etc.), the accompanying information is also rewritten.

According to the series of flows described above, the U-Plane data in the RTP packet arriving from one IP communication network is output to the other IP communication network. At that time, (from the perspective of the destination device) the first RTP transmission/reception unit 203, the U-Plane data processing unit 205, the second RTP transmission/reception unit 208, and the second RTCP transmission/reception unit 209 operate as follows. also do

<First RTP transmission/reception unit 203>
The first RTP transmission/reception unit 203 calculates statistical information (for example, jitter value, packet loss rate, etc.) regarding received RTP packets. Also, the first RTP transmission/reception unit 203 responds with the calculated statistical information in response to the request from the first RTCP transmission/reception unit 204 . At that time, the first RTP transmission/reception unit 203 stores the statistical information in the statistical information storage unit 206 and the U-Plane statistical information storage unit 210. FIG.

<U-Plane data processing unit 205>
The U-Plane data processing unit 205 analyzes the RTP header information of the received RTP packet and the U-Plane data, and determines whether or not the U-Plane data contains a DTMF signal.

For example, the U-Plane data processing unit 205 checks the payload type of the RTP header information and determines whether the corresponding RTP packet is a deemed voice packet or an RFC4733 format RTP packet.

When the RTP packet is determined to be a voice packet, the U-Plane data processing unit 205 determines whether the packet is a "deemed voice RTP packet" containing a DTMF signal. Specifically, the U-Plane data processing unit 205 decodes the U-Plane data using a predetermined (corresponding) audio encoding method, and then performs frequency component analysis to determine whether the DTMF signal is included in the received RTP packet. determine whether or not As a frequency component analysis method, for example, a method using a fast Fourier transform or the Goertzel algorithm described in Patent Document 1 or the like can be adopted. However, the above analysis method is not limited to these.

When it is determined that a DTMF signal is included, the U-Plane data processing unit 205 stores the information of the DTMF signal (eg, detected digit number, signal length, signal level, noise level, detection time, etc.) as statistical information. Stored in unit 206 .

<Second RTCP transmitting/receiving unit 209>
The second RTCP transmitting/receiving unit 209 extracts RTP statistical information (jitter value, number of packet losses) contained in RTCP packets arriving from the other IP communication network, and stores the RTP statistical information in the U-Plane statistical information storage unit 210. Store.

<Statistical information storage unit 206>
The statistical information storage unit 206 accumulates various statistical information for each call. For example, the statistical information storage unit 206 accumulates the following statistical information collected from each processing unit.
- RTP statistical information (for example, jitter value, packet loss rate) input from the first RTP transmitting/receiving unit 203 .
• DTMF signal information input from the U-Plane data processing unit 205 (for example, detected digit number, signal length, signal level, noise level, detection time, etc.).
- RTP statistical information (for example, jitter value, packet loss rate) included in the RTCP packet received from the destination of the RTP packet input from the second RTCP transmitting/receiving unit 209 (as seen from the gateway device 101b).

<Analysis/control unit 207>
Analysis/control unit 207 performs at least one of the following analyzes/instructions/operations (from the standpoint of the destination device) based on various statistical information retrieved from statistical information storage unit 206 .

Action a1:
If at least one of the following cases 1 to 3 applies, the analysis/control unit 207 gives the following instruction (a1-1) or (a1-2). More specifically, the analysis/control unit 207 uses the RTP statistical information calculated when the RTP packet is received, or the RTCP packet included in the RTCP packet received from the other IP communication network that is the destination based on the own device. As a result of analyzing the RTP statistical information, confirm whether one of the following cases 1 to 3 applies.

Case 1:
When the jitter value or packet loss rate is higher than a preset index (threshold). The analysis/control unit 207 gives the following instructions (a1-1) or (a1-2) when the communication quality deteriorates. In other words, the analysis/control unit 207 determines quality deterioration of the communication network based on statistical information calculated by its own device or another communication device, and issues one of the following two instructions.

Case 2:
The detection history of the most recent N (N is a positive integer, hereinafter the same) DTMF signals detected and recognized by the own device, and the DTMF contained in the RTCP packet that arrives from the other IP communication network that is the destination based on the own device When the difference between the signal detection history (when the transmission destination performs operation a2 described later) and the difference between the two exceeds a preset number of mismatches (threshold). If the difference between the number of DTMF signal detections detected by the device itself and the number of DTMF signal detections detected by the destination exceeds a predetermined number of times, the analysis/control unit 207 issues the following instruction (a1- 1) or (a1-2) is performed. In this manner, the analysis/control unit 207 determines the quality deterioration of the communication network based on the detection history of DTMF signals detected by its own device and the detection history of DTMF signals detected by other communication devices. Based on the determination result, the analysis/control unit 207 controls the RTP packet so that the signal length of the DTMF signal stored in the RTP packet and transmitted/received is increased.

Case 3:
When the signal length of the DTMF signal length detected and recognized by the own device is observed as a signal very close to the reference value described in Non-Patent Document 2. In other words, the analysis/control unit 207 determines quality deterioration of the communication network based on the DTMF signal detected by its own device and the standard value (reference value described in Non-Patent Document 2) regarding the DTMF signal. The analysis/control unit 207 performs one of the following two instructions based on the analysis result.

The analysis/control unit 207 performs the following instruction (a1-1) or (a1-2) when the analysis result corresponds to any of the cases 1 to 3 above.

Instruction a1-1:
If the DTMF signal is stored in the RTP packet as “deemed voice”, the analysis/control unit 207 instructs the first RTCP transmission/reception unit 204 . Specifically, the analysis/control unit 207 sends a request to lengthen the DTMF signal length, or information on the signal length specifically desired to be lengthened, to the transmission source device (for example, the gateway device 101a). An instruction is given to the RTCP transmission/reception unit 204 .

Upon receipt of the instruction, the first RTCP transmission/reception unit 204 stores the above information (request to lengthen the DTMF signal length, specific DTMF signal length) in the APP format of the RTCP packet, and sends the RTCP packet to the transmission source device. Send a packet. In addition to the request or specific DTMF signal length information, the effective time of the request may also be transmitted in the RTCP packet.

As for the packet format of the RTCP packet to be used, for example, it is assumed that the RTCP packet is transmitted using an APP type (see Non-Patent Document 1) that can be defined on the application side. However, the format is not limited to this format. For example, information related to the detected DTMF signal may be newly defined as one type of RTCP-XR (see Non-Patent Document 4) and transmitted to the transmission source.

Instruction a1-2:
Analysis/control unit 207 instructs U-Plane data processing unit 205 to convert the U-Plane data so that the DTMF signal length becomes longer when the DTMF signal is transmitted and received as RTP packets of RFC4733 format.

Upon receipt of the instruction, the U-Plane data processing unit 205 operates according to the above instruction when handling the U-Plane data extracted from the RTP packet of RFC4733 format and associated information. Specifically, the U-Plane data processing unit 205 performs conversion processing to replace the U-Plane data extracted from the RTP packets of the RFC4733 format that are continuously received and the accompanying information so that the DTMF signal length becomes longer.

The converted U-Plane data and accompanying information are output to the second RTP transmission/reception section 208 . The second RTP transmission/reception unit 208 converts the U-Plane data into RTP packets according to the acquired U-Plane data and accompanying information, and transmits the packets to the other IP communication network. The conversion process may be stopped when the deterioration of communication quality is resolved, or may be continued until the call is disconnected.

The above instructions (a1-1) and (a1-2) may be selected according to call information determined by communication with a higher-level call control device or an opposite communication device, or It may be set by a setting file or the like of the transmission destination device. For example, even if the DTMF signal is stored in the RTP packet in the RFC4733 format, the analysis/control unit 207 may instruct the transmission source device to lengthen the signal length of the DTMF signal.

Action a2:
The analysis/control unit 207 provides the detection history to the first RTCP transmission/reception unit 204 so as to transmit the detection history of the most recent N DTMF signals to the transmission source device (for example, the gateway device 101a) as an RTCP packet, give the instructions. The first RTCP transmitting/receiving unit 204 that has received the instruction stores the above information (DTMF signal detection history) in the APP format of the RTCP packet in the same manner as the above instruction (a1-1), and sends the RTCP packet to the transmission source device. Send a packet.

Subsequently, the conversion processing of the instruction (a1-2) will be described with reference to the drawings.

4A and 4B are diagrams for explaining the conversion operation of the U-Plane data processing unit 205. FIG. FIG. 4(a) is a diagram showing an example of an RTP packet in a normal state (during non-conversion operation) output from the gateway device. FIG. 4(b) is a diagram showing an example of an RTP packet output from the gateway device during the conversion operation.

FIG. 4 shows RTP header information and RFC4733 information. In FIG. 4, the sequence number (denoted as SN (Sequence Number) in the figure) and the time stamp value (denoted as TS (Time Stamp) in the figure) of the RTP header are information that fluctuates according to time series. For the sake of convenience, specific numerical values are used. Of course, it is not intended to limit these values, such as jitter values, to those disclosed in FIG.

Each column in FIG. 4 indicates information contained in one RTP packet, and the values described in each column are examples of notation assuming that the sampling period is 8 KHz and the RTP packetization period is 20 ms for the audio encoding method used. .

In FIG. 4A, columns #1 to #2 and columns #10 to #12 are voice RTP packets (payload type is 100). Columns #3 to #9 are RTP packets in RFC4733 format, that is, RTP packets corresponding to the DTMF signal portion (payload type is 101).

In addition, the DTMF signal length is equivalent to four columns #3 to #7 (4 columns = 20 ms × 4 = 80 ms, and columns #8 and #9 are indicated as retransmission packets according to Non-Patent Document 3; end bit becomes 1).

As described above, FIG. 4B shows an example of RTP packet transmission when the conversion processing of instruction (a1-2) is performed. In FIG. 4B, columns #1 to #2 and #12 are voice RTP packets, and columns #3 to #11 are DTMF signal portions. In FIG. 4(b), there are six DTMF signal lengths in columns #3 to #9.

As shown in FIG. 4, the DTMF signal length is lengthened by transmitting RFC4733 format RTP packets in columns #10 and #11 in place of voice RTP packets in columns #10 and #11. Note that the audio RTP packets in columns #10 and #11 shown in FIG. 4(a) are the analysis results of the conversion processing shown in FIGS. Using the digit number and signal level information of the DTMF signal included in the received RF4733 packet, the RTP packet of the RFC4733 format in columns #10 and #11 shown in FIG. 4B is replaced. In the example of FIG. 4, the transmission time (Duration) of the DTMF signal is increased from 80 ms (20 m×4 packets) to 120 ms (20×6 packets). In this manner, the U-Plane data processing unit 205 replaces the RTP packets so that the transmission time of the DTMF signal becomes longer.

The U-Plane data processing unit 205 rewrites the payload type of the audio RTP packet following the RTP packet containing the DTMF signal to be converted to the payload type of the RFC4733 format to lengthen the DTMF signal length. The U-Plane data processing unit 205 also rewrites the sequence number, time stamp value, end bit, etc. in addition to the payload type.

Next, a definition example of the APP type of the RTCP packet will be described with reference to Non-Patent Documents 1 and 4 and FIG. FIG. 5 shows an example in which multiple pieces of information are stored in the APP type of one RTCP packet.

An identification ID (Identification) is defined for each piece of information to be placed in the range A portion of FIG. Various information is stored in areas (DATA_1, DATA_2, . . . ) following the ID.

For example, DATA_1 stores request information or a specific DTMF signal length value requested from the sender. DATA_2 stores the expiration date of the information of DATA_1. DATA_3 stores the time information that is the starting point of the validity period described above. DATA_4 stores the detection history of the most recently detected DTMF signals.

Although FIG. 5 is an example in which a plurality of pieces of information are listed, the field definition including the bit allocation of the field is not limited to the field definition in FIG. 5, and another definition may be used.

The U-Plane statistical information storage unit 210 collects, accumulates, and updates call information from the call control unit 201 and RTP statistical information for each call output from a plurality of U-Plane processing units 202 .

An example of information management by the U-Plane statistical information storage unit 210 is shown in FIG. FIG. 6 shows, from the left, a management ID, target IP communication networks (the two IP communication networks are denoted by A and B), communication partner information, call type, statistical value 1, statistical value 2, and DTMF detection of the device itself.・Recognition history etc. are illustrated. In the first embodiment, since each gateway device 101 is connected to the input and output IP communication networks, the input side is distinguished by the branch number "01" and the output side is "02".

In FIG. 6, two columns of statistical values are provided per row. The statistical value 1 stores the packet loss rate as the RTP statistical value received by the own device, and the statistical value 2 stores the RTP statistical information contained in the RTCP packet received from the opposite device (which is the destination from the viewpoint of the own device). It is assumed that the packet loss rate is stored as

The U-Plane analysis/control unit 211 divides the communication calls into groups and analyzes the communication quality for each group. Further, the U-Plane analysis/control unit 211 performs control on RTP packets so that the signal length of the DTMF signals stored in and transmitted and received in RTP packets belonging to the group determined to have degraded communication quality is increased. That is, the U-Plane analysis/control unit 211 groups the opposed devices, and when a quality problem is detected in the group, determines that a similar quality problem has occurred in the sessions in the group, and outputs the DTMF signal control so that the detection of is easily detectable.

Based on the statistical information retrieved from the U-Plane statistical information storage unit 210, the U-Plane analysis/control unit 211 performs at least one analysis/judgment operation out of the following two operations (from the standpoint of the destination device): conduct.

Action b1:
The U-Plane analysis/control unit 211 groups communication calls and analyzes the quality status of each group. Depending on the analysis result, the U-Plane analysis/control unit 211 performs the following (b1-1) or (b1-2) operation.

The above grouping corresponds to, for example, grouping by IP address, by call type, by provided service, etc., and is given from the outside according to the connection relationship.

An example will be explained. The U-Plane analysis/control unit 211 groups the opposite IP addresses used for call connection within the IP communication network by network address. In the example of FIG. 6, on the IP communication network A side, management IDs 202A-01, 202B-1, and 202D-01 are classified into the same group, and 202C-01 and 202E-01 are classified into the same group.

After grouping, the U-Plane analysis/control unit 211 analyzes the RTP statistical information of the communication calls belonging to each group. Specifically, the U-Plane analysis/control unit 211, when the number of calls exceeding a preset criterion for the index value exceeds the specified number (when the threshold is exceeded), the U-Plane analysis/control unit 211 determines that the network address group is subjected to "quality deterioration occurrence”.

As a result of the analysis, when it is determined that "quality deterioration has occurred", the U-Plane analysis/control unit 211 performs one of the following two operations.

Action (b1-1):
The U-Plane analysis/control unit 211 sends a request to lengthen the signal length of the DTMF signal or a signal length value specifically desired to be lengthened to the transmission source device using an RTCP packet, and requests the call belonging to the corresponding group. An instruction is given to the U-Plane processing unit 202 that is controlling. Upon receipt of the instruction, the U-Plane processing section 202 performs the same operation as the first RTCP transmitting/receiving section 204 explained in the instruction (a1-1) for calls belonging to the corresponding group.

Action (b1-2):
When the DTMF signal is communicated by RTP in the RFC4733 format, the U-Plane analysis/control unit 211 controls calls belonging to the corresponding group so as to convert the DTMF signal length to be longer. An instruction is given to the processing unit 202 . The U-Plane processing unit 202 that has received the instruction performs the same operation as the U-Plane data processing unit 205 and the second RTP transmission/reception unit 208 described in the instruction (a1-2) for calls belonging to the corresponding group. I do.

The operation of the gateway device 101 as a transmission destination is summarized as shown in the flow chart of FIG.

The gateway device 101 determines whether or not the RTP packet contains a DTMF signal (step S01).

If the RTP packet does not contain a DTMF signal (step S01, No branch), the gateway device 101 repeats the process of step S01.

If the RTP packet contains a DTMF signal (step S01, Yes branch), the gateway device 101 analyzes the statistical information or the DTMF detection history, and determines whether or not quality deterioration has occurred in the IP communication network ( step S02).

If quality deterioration has not occurred (step S02, No branch), the gateway device 101 terminates the process.

If quality deterioration has occurred (step S02, Yes branch), the gateway device 101 determines the format (type) in which the DTMF signal is stored in the RTP packet (step S03).

If the storage type is "deemed voice", the gateway device 101 instructs other communication devices to lengthen the signal length of the DTMF signal (step S04).

If the storage type is "RFC4733 format", the gateway apparatus 101 converts the RTP packet so that the signal length of the DTMF signal becomes longer in the internal module of the own apparatus (step S05).

[Operation as a transmission source device (RTP packet transmission device)]
Next, the operation of the transmission source device will be described with respect to the points that differ from the operation contents of the transmission destination device described above.

As described above, consider the gateway device 101a as the source device and the gateway device 101b as the destination device.

Assume that the source device (gateway device 101a) receives an RTCP packet from the destination device (gateway device 101b) in the second RTCP transmission/reception unit 209 . At this time, if the received RTCP packet contains request information indicating that the signal length of the DTMF signal is desired to be lengthened, or a specific signal length value desired to be lengthened, the second RTCP transmission/reception unit 209 The information is output to the analysis/control unit 207 .

The analysis/control unit 207 determines/instructs one of the following two operations. It should be noted that which operation is selected can be selected according to call information determined by communication with a higher-level call control device of the transmission source device or the opposite communication device. However, if it is known in advance whether the transmission source is compatible with DTMF signal decompression control and transmission control, a mechanism may be adopted in which selection can be made by a setting file or the like of the transmission destination device.

Action c1:
When the generation point of the DTMF signal is the source viewed from the device (for example, in FIG. 2, the source viewed from the gateway device 101a is the user terminal), or when it is difficult for the device to change the signal length of the DTMF signal. In this case, the analysis/control unit 207 performs the same operation as the operation (a1-1) described above.

Action c2:
When the generation point of the DTMF signal is the device itself, the analysis/control unit 207 instructs to generate an RTP packet so that the signal length of the DTMF signal becomes longer as in (a1-2) above. . Specifically, audio data is generated so that the transmission time of the DTFM signal stored in the RTP packet as "deemed audio" is long, and is stored in the RTP packet by an RTP packet generating means (for example, an audio input unit described later). 502) is instructed.

As described above, the gateway device 101 according to the first embodiment observes and aggregates packet loss occurrence conditions associated with IP communication network congestion, failures, and the like, and performs analysis in consideration of DTMF signal detection conditions. After that, the gateway device 101 feeds back a transmission control request and the like regarding the DTMF signal to the transmission source communication device. Based on the request, the transmission source device (or the further transmission source device where the DTMF signal is generated) performs transmission control such as extending the DTMF time length. As a result, in communications that transmit and receive DTMF signal information in RTP packets, the DTMF signal is not detected at the destination device due to deterioration in the quality of the communication network (for example, an increase in the jitter value or packet loss rate), and services based on the DTMF signal accompanying the detection become unusable. Reduction (avoidance) of quality deterioration is realized.

In addition, in the first embodiment, it is expected that non-detection of DTMF signals can be reduced or avoided in preparation for the possibility of deterioration in communication quality in the future for communication calls with no problem in communication quality. can. In the first embodiment, a transmission partner (source/destination device seen from its own device) is analyzed for each group (for example, grouped by IP network address), and the quality of a plurality of communication calls belonging to the group is analyzed. This is for checking and controlling whether or not there is a bad thing. In the first embodiment, when deterioration of communication quality regarding a certain communication call is detected, the sender is prompted to control the transmission of DTMF signals for another communication call belonging to the same IP network address, and the entire group preemptively avoids problems with DTMF signals that may arise in

[Second embodiment]
Next, a second embodiment will be described in detail with reference to the drawings.

The disclosure of the present application may be applied not only between gateway devices, but also, for example, in FIG. 2, where the source device is the user terminal 102 and the destination device is the gateway device 101a, and it may be applied to a control method therebetween. In the second embodiment, the above configuration and operation will be described.

The configuration, operation, etc. of the gateway device 101 of the destination device are the same as those of the destination device described in the first embodiment.

FIG. 8 is a diagram showing an example of the processing configuration of the user terminal 102 according to the second embodiment. Referring to FIG. 8, user terminal 102 includes second call control unit 501, voice input unit 502, second U-Plane data processing unit 503, third RTP transmission/reception unit 504, and third An RTCP transmission/reception unit 505 , an audio output unit 506 , a screen control unit 507 and a control unit 508 are provided.

The second call control unit 501 terminates call control with the opposite communication device, and becomes capable of communicating with subordinate units (voice input unit 502 to control unit 508) according to the contents of the call control. Set and control call information.

The speech input unit 502 acquires the user's speech and outputs it to the second U-Plane data processing unit 503 as U-Plane data.

It should be noted that when the user presses the push button during communication, the call information of the second call control unit 501 can be used to convey the DTMF signal as "deemed voice". In this case, the voice input unit 502 generates a DTMF signal assigned in advance to each push button, and outputs U-Plane data to the second U-Plane data processing unit 503 as "deemed voice".

In the case of communication in which a DTMF signal is transmitted in the RFC4733 format according to the instruction of the second call control unit 501, the voice input unit 502 receives the acquired U-Plane data, as well as the DTMF signal assigned to each button in advance. Signal information is also output to the second U-Plane data processing unit 503 as accompanying information.

The information of the DTMF signal is information such as the digit number, signal level, time length, etc., which can be used as the basis for finally constructing the RTP packet of RFC4733 in the third RTP transmitting/receiving section 504 . Note that when the voice input unit 502 transmits a DTMF signal, the voice input unit 502 outputs it to the control unit 508 as a “DTMF signal transmission history”.

In addition, the voice input unit 502 performs operations described later when receiving an instruction from the control unit 508 .

The second U-Plane data processing unit 503 encodes the U-Plane data input from the voice input unit 502 according to the call information input from the second call control unit 501 using a predetermined voice encoding method. become The encoded U-Plane data is output to third RTP transmission/reception section 504 . Further, when accompanying information exists together with the U-Plane data, second U-Plane data processing section 503 also outputs the accompanying information to third RTP transmitting/receiving section 504 .

In addition, as an operation in the opposite direction, the second U-Plane data processing unit 503 receives the encoded U-Plane data input from the third RTP transmission/reception unit 504, and processes the encoded U-Plane data. - Decode the Plane data and output the obtained U-Plane data to the audio output unit 506 . If accompanying information is present in the input from the third RTP transmitting/receiving section 504 , the accompanying information is also output to the audio output section 506 .

The third RTP transmitting/receiving unit 504 converts the encoded U-Plane data input from the second U-Plane data processing unit 503 into RTP packets and transmits them to the opposite communication partner. Further, U-Plane data obtained as a result of jitter buffer control and packet analysis regarding RTP packets received from the opposite communication partner is output to second U-Plane data processing section 503 .

The third RTP transmission/reception unit 504 calculates statistical information related to RTP packet transmission/reception and outputs it as a response to the request from the third RTCP transmission/reception unit 505 . The third RTP transmitting/receiving unit 504 utilizes RTP statistical information (for example, packet loss rate, jitter value, etc.) included in RTCP packets received from the opposite communication partner, which is input from the third RTCP transmitting/receiving unit 505. , RTP transmission/reception control.

The third RTCP transmitting/receiving unit 505 outputs various statistical information contained in the RTCP packets arriving from the IP communication network to the third RTP transmitting/receiving unit 504, and outputs control information to the control unit 508, respectively. The third RTCP transmitting/receiving unit 505 periodically transmits RTCP packets, forms RTCP packets based on information/instructions from the control unit 508, and transmits the RTCP packets to the IP communication network.

The audio output unit 506 outputs (reproduces) the U-Plane data input from the second U-Plane data processing unit 503 as audio to the user. Alternatively, if there is accompanying information, the audio output unit 506 refers to this information as information relating to RFC4733 (DTMF signal), and generates and reproduces the designated DTMF signal. The audio output unit 506 performs predetermined control operations according to instructions from the control unit 508 .

Screen control unit 507 displays the start/end of communication in accordance with instructions from second call control unit 501 , or performs predetermined screen display in accordance with instructions from control unit 508 and voice input unit 502 .

[Explanation of operation]
Next, operation of the system according to the second embodiment will be described.

The operation of the transmission destination device is the same as that of the first embodiment, and will be explained as the operation of the transmission source device. For the user terminal 102, the second call control unit 501 uses the call information (IP address, UDP port number, voice coding method to be used, RTP payload type value, etc.) determined by communication with the communication device on the other end to perform RTP In order to enable communication, setting and control for starting/ending communication are performed for each included processing module.

Regarding the RTP transmission operation after the call connection is completed, the voice input unit 502 acquires the user's voice via a sound collecting unit such as a microphone, and outputs it as U-Plane data to the second U-Plane data processing unit 503. .

Note that when the user presses a push button, the setting from the second call control unit 501 is referred to, and in the case of a call in which the DTMF signal is transmitted by "deemed voice", the voice input unit 502 preliminarily A DTMF signal is created from the assigned DTMF signal information, and output to the second U-Plane data processing unit 503 together with the DTMF signal information as U-Plane data.

On the other hand, in the case of a call that transmits a DTMF signal in the RFC4733 format, the voice input unit 502 sends U-Plane data corresponding to silence and DTMF signal information as accompanying information to the second U-Plane data processing unit 503. Output.

The DTMF signal information is information such as the digit number, signal level, and signal time length corresponding to the pressed push button. information that can be used by

At the output timing when the DTMF signal is not transmitted, the voice input unit 502 makes the attached information null, for example, so that the subsequent processing unit can distinguish between DTMF transmission and non-transmission.

The second U-Plane data processing unit 503 encodes the U-Plane data and accompanying information input from the audio input unit 502 according to a predetermined audio encoding method, and encodes the U-Plane data. The received U-Plane data and associated information are output to the third RTP transmitting/receiving unit 504 .

The third RTP transmission/reception unit 504 performs one of the following two operations and outputs RTP packets to the IP communication network.

(1) When the accompanying information is empty, the third RTP transmitting/receiving section 504 converts the encoded U-Plane data into RTP.
(2) If there is accompanying information, the third RTP transmitting/receiving unit 504 converts the accompanying information into RTP packets in the RFC4733 format.

Further, regarding the RTCP packet transmission operation, the third RTCP transmission/reception unit 505 acquires RTP statistical information from the third RTP transmission/reception unit 504 at regular intervals, constructs RTCP packets based on the information, and transmits the RTCP packets to the IP communication network. output to

Regarding the RTP reception operation after the call connection is completed, the RTP packet received by the third RTP transmission/reception unit 504 is encoded U-Plane data or DTMF contained in RFC4733 as a result of jitter buffer control and packet analysis. The signal information is output to second U-Plane data processing section 503 as accompanying information.

In the second U-Plane data processing unit 503, if the data input from the third RTP transmitting/receiving unit 504 is encoded U-Plane data, it is decoded, and the obtained U-Plane data is output to an audio output unit. output to 506; At that time, if accompanying information is included, the second U-Plane data processing unit 503 outputs the information to the audio output unit 506 as well.

The audio output unit 506 reproduces the U-Plane data from the second U-Plane data processing unit 503, or if accompanying information exists, it also refers to the accompanying information and outputs the U-Plane data of the DTMF signal. Generate and play.

The RTCP packets received by the third RTCP transmitting/receiving unit 505 are subjected to packet analysis, and the obtained statistical information/control information is output to the third RTP transmitting/receiving unit 504 . These pieces of information are utilized for transmission/reception control of RTP packets.

The above description is an operation example of normal RTP/RTCP packet communication, but the features of the second embodiment will be described below.

When the third RTCP transmitting/receiving unit 505 analyzes the RTCP packet received from the remote device, the received RTCP packet contains a request indicating that the signal length of the DTMF signal is to be increased, as described in the first embodiment. If information, a signal length value specifically desired to be lengthened, or a detection history of a DTMF signal is included, the information is output to the control unit 508 .

The control unit 508 instructs/operates one of the following two operations according to the above information.

Action d1:
If the information indicating that the DTMF signal length is desired to be lengthened is included, or if the value of the signal length that is specifically desired to be lengthened is included, the control unit 508 sends the same information to the voice input unit 502. instruct.

Upon receipt of the instruction, the voice input unit 502 increases the signal length of the DTMF signal generated when the user presses the push button after receiving the instruction, if the above request can be met. Alternatively, it generates a DTMF signal according to the indicated value and outputs it to the second U-Plane data processing section 503 as U-Plane data. Note that if the expiration date and the time information that is the starting point of the expiration date are also included, the control unit 508 outputs the information to the voice input unit 502 together with this information.

Action d2:
If the detection history of the DTMF signal is included, the control unit 508 collates it with the accumulated transmission history of the most recent N times. In addition, considering the possibility that the user terminal 102 has just transmitted the "deemed voice" corresponding to the DTMF signal or the RTP packet in the RFC4733 format and the destination device has not detected it, the DTMF signal transmitted immediately before The transmission history may be excluded from the collation targets.

As a result of collation, if a predetermined number or more of inconsistent portions are confirmed in both histories, the control unit 508 instructs the voice input unit 502 to lengthen the signal length of the DTMF signal.

After receiving the instruction, the voice input unit 502 generates a DTMF signal with a value obtained by lengthening the signal length of the DTMF signal generated when the user presses the push button by a predetermined constant ratio, and converts the U-Plane data. , and output to the second U-Plane data processing unit 503 .

Note that if the expiration date or the time information that is the starting point of the expiration date is also included, the voice input unit 502 may return to the process of generating with the normal DTMF signal length after a certain period of time has elapsed according to the information, or may disconnect the call. You may continue until

Regarding the control unit 508, when performing a series of operations for lengthening the comparison result of the detection history and the transmission history and the DTMF signal length, the voice output unit 506 is instructed to reproduce an alarm sound, or the screen control unit 507 is instructed. However, it is also possible to display the progress of the detection status of the opposing device or to prompt the user to move to a stable communication area.

[Hardware configuration]
Next, the hardware configuration of each device included in the system will be described.

FIG. 9 is a diagram showing an example of the hardware configuration of the gateway device 101. As shown in FIG. The gateway device 101 has a configuration illustrated in FIG. For example, the gateway device 101 includes a CPU (Central Processing Unit) 301, a memory 302, a communication means such as a NIC (Network Interface Card) 303, etc., which are interconnected by an internal bus.

However, the configuration shown in FIG. 9 is not meant to limit the hardware configuration of the gateway device 101. FIG. The gateway device 101 may include hardware (not shown). The number of CPUs and the like included in the gateway device 101 is not limited to the example shown in FIG.

The memory 302 is a RAM (Random Access Memory), a ROM (Read Only Memory), an auxiliary storage device (such as a hard disk), or the like.

The functions of the gateway device 101 are implemented by the processing modules described above. The processing module is implemented by the CPU 301 executing a program stored in the memory 302, for example. Also, the program can be downloaded via a network or updated using a storage medium storing the program. Furthermore, the processing module may be realized by a semiconductor chip. In other words, the functions performed by the processing modules may be realized by some kind of hardware or software executed using hardware.

Note that the basic hardware configuration of the user terminal 102 can be the same as that of the gateway device 101, and since it is obvious to those skilled in the art, detailed description thereof will be omitted.

[Modification]
It should be noted that the configuration, operation, etc. of the communication system described in the above embodiment are examples, and are not meant to limit the configuration, operation, etc. of the system. For example, in the above embodiment, when lengthening the signal length of the DTMF signal of the RTP packet of the RFC4733 format, the voice RTP packet is converted (replaced) with the RTP packet containing the DTMF signal. Instead of such conversion, a new RFC4733 format RTP packet may be inserted (added) so as to increase the signal length of the DTMF signal. For example, referring to FIG. 4, RTP packets in the RFC4733 format of columns #10 and #11 of FIG. 4(b) may be inserted between columns #9 and 10 of FIG. 4(a). Even in this case, conversion (for example, conversion of columns #7 to #9 in FIG. 4(a)) is required to ensure consistency of the result of lengthening the signal length of the DTMF signal.

Also, in the flowchart used in the above description, a plurality of steps (processes) are described in order, but the execution order of the steps executed in each embodiment is not limited to the described order. In each embodiment, the order of the illustrated steps can be changed within a range that does not interfere with the content, such as executing each process in parallel. Moreover, each of the above-described embodiments can be combined as long as the contents do not contradict each other.

From the above description, the industrial applicability of the present invention is clear. It can be suitably applied to a media gateway device or the like arranged in a network.

Some or all of the above embodiments may also be described in the following additional remarks, but are not limited to the following.
[Appendix 1]
This is the same as the communication device according to the first aspect described above.
[Appendix 2]
The RTP transmission/reception unit calculates statistical information indicating the quality of the communication network from the received RTP packets,
Preferably, the communication device according to appendix 1, wherein the analysis control unit determines quality deterioration of the communication network based on the statistical information.
[Appendix 3]
Preferably, the communication according to appendix 1, wherein the analysis control unit determines quality deterioration of the communication network based on a detection history of DTMF signals detected by the own device and a detection history of DTMF signals detected by other communication devices. Device.
[Appendix 4]
Preferably, the communication device according to appendix 1, wherein the analysis control unit determines quality deterioration of the communication network based on the DTMF signal detected by the device itself and a standard value for the DTMF signal.
[Appendix 5]
5. Preferably, the communication device according to any one of Appendices 1 to 4, wherein the analysis control unit instructs another communication device to increase the signal length of the DTMF signal stored in the RTP packet.
[Appendix 6]
further comprising a data processing unit that performs a predetermined conversion process on user data contained in the received RTP packet,
The analysis control unit instructs the data processing unit to convert the user data so that the signal length of the DTMF signal becomes longer when the DTMF signal is stored in the RTP packet according to the RFC4733 format. , preferably according to any one of appendices 1 to 4.
[Appendix 7]
The data processing unit determines whether the DTMF signal is stored in the RTP packet as deemed voice, or whether the DTMF signal is stored in the RTP packet in accordance with RFC (Request for Comments) 4733 format, preferably as described in Appendix 6 Communication device as described.
[Appendix 8]
The communication call is divided into groups, the communication quality is analyzed for each group, and the signal length of the DTMF signal that is stored in the RTP packet that belongs to the group that is determined to have deteriorated in communication quality and is transmitted and received is made longer. 8. Preferably, the communication device according to any one of Appendices 1 to 7, further comprising a U-Plane (user plane) analysis control unit that performs control on RTP packets.
[Appendix 9]
Preferably, the communication device according to appendix 7 or 8, wherein the data processing unit performs frequency component analysis after decoding user data using a voice coding method, and determines whether or not a DTMF signal is included in an RTP packet.
[Appendix 10]
10. The communication device according to any one of Appendices 1 to 9, preferably, wherein the statistical information is at least one of packet loss rate and jitter value.
[Appendix 11]
This is the same as the communication method according to the second aspect described above.
[Appendix 12]
It is as the program related to the above-mentioned 3rd viewpoint.
Note that the form of Appendix 11 and the form of Appendix 12 can be developed into the form of Appendix 2 to the form of Appendix 10 in the same manner as the form of Appendix 1.

The disclosures of the cited patent documents and the like are incorporated herein by reference. Within the framework of the full disclosure of the present invention (including the scope of claims), modifications and adjustments of the embodiments and examples are possible based on the basic technical concept thereof. Also, various combinations or selections of various disclosure elements (including each element of each claim, each element of each embodiment or example, each element of each drawing, etc.) within the framework of the full disclosure of the present invention (including partial deletion) is possible. That is, the present invention naturally includes various variations and modifications that can be made by those skilled in the art according to the entire disclosure including claims and technical ideas. In particular, any numerical range recited herein should be construed to specifically recite any numerical value or subrange within that range, even if not otherwise stated.

10 communication device 11 RTP transmission/reception unit 12 analysis control units 101, 101a, 101b gateway device 102 user terminal 201 call control units 202, 202a to 202n U-Plane processing unit 203 first RTP transmission/reception unit 204 first RTCP transmission/reception unit 205 U-Plane data processing unit 206 Statistical information storage unit 207 Analysis/control unit 208 Second RTP transmission/reception unit 209 Second RTCP transmission/reception unit 210 U-Plane statistical information storage unit 211 U-Plane analysis/control unit 301 CPU (Central Processing Unit)
302 memory 303 NIC (Network Interface Card)
501 second call control unit 502 voice input unit
503 second U-Plane data processing unit 504 third RTP transmission/reception unit 505 third RTCP transmission/reception unit 506 audio output unit 507 screen control unit 508 control unit

Claims (10)

an RTP transmitting/receiving unit for transmitting/receiving RTP (Real time Transport Protocol) packets;
an analysis control unit that determines whether quality deterioration has occurred in a communication network that transmits RTP packets;
with
If the DTMF signal is stored in the RTP packet in accordance with the RFC4733 format, the analysis control unit determines that the quality of the communication network is degraded, and if the DTMF signal is stored in the RTP packet and transmitted/received ( Dual-Tone Multi-Frequency) A communication device that controls RTP packets so that the signal length of the signal is long. The RTP transmission/reception unit calculates statistical information indicating the quality of the communication network from the received RTP packets,
2. The communication device according to claim 1, wherein said analysis control unit determines quality deterioration of said communication network based on said statistical information. 2. The communication device according to claim 1, wherein said analysis control unit determines quality deterioration of said communication network based on a detection history of DTMF signals detected by said device and a detection history of DTMF signals detected by other communication devices. . 2. The communication device according to claim 1, wherein said analysis control unit determines quality deterioration of said communication network based on a DTMF signal detected by said device and a standard value for said DTMF signal. If the DTMF signal is stored in the RTP packet as "deemed voice", the analysis control unit, when determining that quality deterioration has occurred in the communication network, performs RTP 5. The communication device according to any one of claims 1 to 4, which instructs to increase the signal length of the DTMF signal stored in the packet. further comprising a data processing unit that performs a predetermined conversion process on user data contained in the received RTP packet,
The analysis control unit instructs the data processing unit to convert the user data so that the signal length of the DTMF signal becomes longer when the DTMF signal is stored in the RTP packet according to the RFC4733 format. A communication device according to any one of claims 1 to 4. 7. The data processing unit according to claim 6, wherein the data processing unit determines whether the DTMF signal is stored in the RTP packet as assumed voice or whether the DTMF signal is stored in the RTP packet in accordance with RFC (Request for Comments) 4733 format. communication equipment. The communication call is divided into groups, the communication quality is analyzed for each group, and the signal length of the DTMF signal that is stored in the RTP packet that belongs to the group that is determined to have deteriorated in communication quality and is transmitted and received is made longer. 8. The communication device according to any one of claims 1 to 7, further comprising a user plane analysis control unit that performs control on RTP packets. in a communication device,
sending and receiving RTP (Real time Transport Protocol) packets;
determining whether quality deterioration has occurred in a communication network that transmits RTP packets;
When it is determined that the quality of the communication network is degraded, and the DTMF signal is stored in the RTP packet in accordance with RFC4733 format, the DTMF (Dual-Tone Multi-Frequency ) controlling the RTP packet so that the signal length of the signal is long;
communication methods, including A computer installed in a communication device,
A process of transmitting and receiving RTP (Real time Transport Protocol) packets;
A process of determining whether quality deterioration has occurred in a communication network that transmits RTP packets;
When it is determined that the quality of the communication network is degraded, and the DTMF signal is stored in the RTP packet in accordance with RFC4733 format, the DTMF (Dual-Tone Multi-Frequency ) a process of controlling the RTP packet so that the signal length of the signal is long;
program to run.

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