WO2007131397A1

WO2007131397A1 - Data redundancy transmitting method and system

Info

Publication number: WO2007131397A1
Application number: PCT/CN2006/003179
Authority: WO
Inventors: Hu Li
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2006-05-17
Filing date: 2006-11-27
Publication date: 2007-11-22
Also published as: CN101047604A

Abstract

A data redundancy transmitting method and system in 3GPP network redundantly encodes the UP user plane protocol head into a payload type which is required and transmits it to the media gateway by the media gateway controller after the media gateway controller negotiates with the media gateway and determines the connection message payload type based on ITU G711 protocol. The present invention solves the data reliability problem of circuit field data service in IP network in wireless networks, thereby increases the service success rate and service quality of data transmission.

Description

Data redundancy transmission method and system

The present invention relates to a data redundancy transmission method and system, and more particularly to a method and system for redundantly transmitting wireless circuit domain data services in a core network. Scenery technology

IWF (Interworking Function) is a device that conceals physical link and network technology when protocol conversion in circuit domain data service between wireless network and heterogeneous network. It is GSM WCDMA (Global System for Mobile Communications/ Wide) -band Code Division Multiple Access; global mobile communication system/wideband code division multiple access system) and PSTN (public switched telphone network; public switched telephone network), ISDN (Integrated Services Digital Network), PSPDN ( Packet Switched Public Data Network; A switching function device for circuit domain data service interworking. The IWF's services in the circuit domain are divided into 3.1 khz, UDI (unresctricted digital information) and two bearer capabilities, of which 3.1khz bearer capability can support Modem/Fa services.

In GSM, because no packet domain is defined, data services can only be carried out through the IWF. If a user wants to access the Internet through a mobile phone, it can only dial in to the PSTN/ISDN access server through the IWF and then access the Internet through the access server. After the emergence of GPRS (General Packet Radio Service), there are two ways to access the Internet through mobile phones. Sending faxes to PSTN and ISDN fax machines via GSM and GPRS is an important function of IWF. There are no other functions that can be replaced.

In the 3G era, the functions of the IWF were gradually weakened into some point-to-point services: fax, remote monitoring, remote maintenance, etc. However, the IWF is a must-have function for gateway devices to access the network. Otherwise, the gateway device cannot access the network and inherit the original service. In addition, it is also a function that is very popular in countries such as Russia. In the wireless core network, after the circuit domain data service passes the IWF, the Modem/Fax/UDI service is currently processed as a 64Kbps code stream, wherein the 64Kbps code stream uses the G711 coding scheme, and the R4 standard needs to be used for the user plane data. The N up (Nb interface User Plane) frame processing mode is supported as a user layer protocol. In the existing 3GPP R4/5/6 version, the 3GPP protocols 29.007, 23.910 and other specifications are defined as follows: Section 11.5.2 of 29007, after IWF transmission, Modem signal to PCM (pulse code modulation) The method performs G711 coding and 64 Kbit/s code stream bandwidth transmission. The protocol unit is 40 bytes in size, 5ms is sent in time interval, and the user plane uses the UP (User Plane; User Plane) protocol in support mode. The scheme is similar to the G711 5ms packing mode in the fixed network to transmit the Modem/Fax service, but the UP protocol header is added. There are similar definitions in 23.910.

Because ATM (Asynchronous Transfer Mode) network quality is reliable, this solution has no problem in the ATM network, but in the IP (internet protocol) network, packet loss occurs due to unreliable IP network quality. , out of order and other issues. The out-of-order problem can be solved by a certain depth of JB (Jitter Buffer). For the packet loss problem, although there is no serious problem in voice, but for Modem/fax/UDI service, there will be serious business impact. Because Modem/Fax/UDI is sensitive to packet loss, the implementation of the IWF core network currently defined by 3GPP (3rd Generation Partnership Project) is feasible in the ATM core network, but It is not feasible in IP networks.

Practice has proved that when the 5ms G711 transmits Modem/Fax services over the IP network, the quality of the service can only be guaranteed if the IP network quality is good. For 1%, 40ms jitter IP network, Modem/fax/UDI service quality cannot be guaranteed. Modem and Fax are easy to re-negotiate, but in the end they often fail because of too many negotiation times. For the UDI service, only the retransmission of the link layer can guarantee the quality of the service. For the non-retransmission service, it is difficult to guarantee the quality of the service.

In the scheme specified in the load format RFC2198 specification for encoding redundant audio data when using RTP (Real Time Transport Protocol), the specification defines the redundancy mode of the audio data service in the fixed network, by adding Redundant RTP payloads increase anti-drop capability. When a packet loss occurs, the subsequent packet carries the previous packet, and the receiver fills in the lost packet, thus ensuring the continuous integrity of the data stream. The number of redundant packets can be controlled by the signaling plane H.248 protocol. RFC 2198 defines redundancy based on the PT (payload type) of the RTP.

The number of redundant data packets is generally determined according to the network quality. If the network quality is good, use one. If the network quality is poor, use two. This process is documented in IETF RFC 2198. The maximum number of messages that can be recovered is three. The signaling plane determines the indication of several redundancy through the corresponding QoS (Quality of Service) indicator. Redundant data transmission technology Although it can prevent packet loss and improve data transmission reliability and service quality, this technology cannot be directly used in wireless environments.

In summary, there is no advantage of the redundant data transmission technology that can utilize the RPC2198 protocol to meet the defects of the wireless circuit domain data service defined in the wireless protocol in the core network, so that the wireless service can be in the IP network. normal operation. SUMMARY OF THE INVENTION

The present invention provides a data redundancy transmission method for solving the advantages of the redundant data transmission technology that cannot utilize the RFC2198 protocol, so as to satisfy the defect that the wireless circuit domain data service defined in the wireless protocol is transmitted in the core network, so that The problem that wireless services can operate normally in an IP network.

A data redundancy sending method of the present invention includes the following steps:

A. The media gateway controller negotiates with the media gateway to connect the payload type of the packet;

B. The media gateway sends a packet carrying the required payload type to the media gateway controller.

C. The media gateway controller sends the payload type required for the redundancy of the UP user plane protocol header to the media gateway according to the payload type required by the media gateway.

Preferably, the media gateway controller in step A negotiates the connection message payload type with the media gateway in real time.

Preferably, the message in step A is a message of the ITU G711 coding scheme.

Preferably, the media gateway controller and the media gateway negotiate to send by using an IP bearer control protocol. Message.

Preferably, the media network gateway and the media gateway negotiate to send a message through a control plane.

Preferably, wherein the redundant coding in step C is performed on a real-time transport protocol layer. Preferably, the number of redundancy of the UP user plane protocol header in step C is determined by the signaling plane through a corresponding network quality of service indicator.

Preferably, the number of the redundancy is '2 or 3.

The present invention also provides a data redundancy transmission system, including a media gateway controller and a media gateway, and a data redundancy coding module, configured to negotiate a connection message based on the ITU G711 protocol by the media gateway controller and the media gateway. After the payload type, the UP user plane protocol header is redundantly encoded into the required payload type and sent by the media gateway controller to the media gateway.

The invention treats the redundant transmission method in the ITU protocol by using the UP header as a dynamic coding in the G711 coding scheme, thereby solving the data reliability problem of the circuit domain data service in the wireless network on the IP network. Thereby improving the service success rate and service quality of data transmission. DRAWINGS

1 is a schematic structural diagram of a protocol stack on an IP core network according to an embodiment;

2 is a schematic flowchart of an implementation process of redundancy transmission according to an embodiment;

FIG. 3 is a schematic diagram of a data packet defined by the RTP audiovisual framework [3] according to the embodiment. detailed description

Specific embodiments of the present invention will be described below with reference to the accompanying drawings.

For the case where the quality of data transmission over IP networks is difficult to guarantee, an improvement is needed specifically for IP networks. The invention is considered to be solved by means of packet redundancy. Since in terms of circuit domain, 3GPP packetization includes IP and ATM, and 3GPP2 packetization has only one all-IP method. There is no UP protocol in the IP core network of 3GPP2. Therefore, the IP modes of the two system circuit domains are basically the same. Therefore, the solution for transmitting Modem/Fax UDI services on the IP core network in 3GPP can also be used in the IP core network of 3GPP2. . In the existing 3GPP R4/5/6 version, after IWF transmission, the Modem signal is transmitted in PCM mode (G711), 64Kbit/s code stream bandwidth, the user plane uses the UP mode of the support mode, and the G711 in the fixed network. The 5ms packet mode transmits the Modem/Fax service. The difference is that the UP protocol header is added. Therefore, the ITU protocol can be extended, and the G711 with the UP protocol header is redundant to ensure the normal operation of the service in the IP network, that is, the G711 with the UP protocol header. It is viewed as a dynamically encoded content for transmission purposes.

In the wireless network, after the circuit domain data service passes through the IWF, it is transmitted on the IP network by means of Modem/Fax or UDI 64 kbps PCM. For Modem/Fax's 64Kbps PCM signal, it is actually a G711 a rate or a u rate code. For UDI's 64Kbps PCM stream, it is actually a byte stream, there is no a rate, u rate. Figure 1 is a schematic diagram of the structure of the IP core network protocol stack. The structure of the IP core network protocol stack is as shown in the figure, including G711 40-byte payload, UP protocol header 4 bytes, RTP protocol header, UDP protocol header, IP protocol header, Ethernet protocol header.

If any packet is lost, the Modem/fax/UDI signal will be lost, causing the Modem/Fax UDI to renegotiate or slow down. If the number of times is too large, the call will be removed and the service success rate will be reduced.

The redundancy of the RTP payload is used at the RTP level after the redundancy mechanism is used. Therefore, the content on the RTP protocol layer is redundantly repeated. The message format is as follows:

RTP header + 2198 headers (9B) + UP headers 1 + G711 40Bytes + UP headers 2 + G711 40bbytes + UP headers 3 + G711 40Bytes.

Among them, the UP protocol header refers to the UP protocol part. The UP header 1/2/3 is used to indicate the UP header of three packets according to the method specified by the UP protocol; the redundancy information is carried in the RTP header, and the number of redundancy is controlled by (Media Gateway Controller; Media Gateway Controller). It is indicated in the RTP header and is reflected in the payload; the UP header 1/2/3 indicates the corresponding redundant packet.

For G711, there are two types of payload: a rate, u rate. However, in the wireless environment, because the UP protocol layer is added, when the G711 has the UP protocol header, the G711 payload type can no longer be used, and the dynamically negotiated payload type must be uniformly used. When extended use is required, the control plane should specify the RTP payload type, and there are two ways to negotiate the RTP payload type in the wireless environment. Use IPBCP (IP Bearer Control Protocol) negotiation and control plane designation.

For the control of the number of redundant packets: it can be controlled by many schemes, which are generally divided into: MGC control and MGW (Media Gateway; Media Gateway) to control or configure itself.

For the mode of controlling redundant packets, you can also use the method of configuring the entire network: that is, the entire network is considered to be the MGW of a certain manufacturer, so that both sides of the transmitted message format can be identified and processed. You can also use the identity detection method: that is, to identify whether the other party is the MGW of the own manufacturer by a private method, and then decide whether to send such a redundant message.

The following describes a specific implementation of controlling the redundant message through the control interface between the MGW and the MGC using the MGC.

2 is a schematic flowchart of the implementation of the redundant packet sending according to the present invention. As shown in the figure, the method includes: Step 201: The MGC media gateway controller negotiates with the MGW media gateway to connect the payload type of the packet;

Step 202: The MGW media gateway sends a packet carrying the required payload type to the MGC media gateway controller.

Step 203: The MGC media gateway controller sends the UP user plane protocol header to the required payload type to the MGW media gateway according to the payload type required by the MGW media gateway.

According to the same principle, the present invention also provides an implementation manner of a data redundancy sending system. The system includes a body gateway controller and a media gateway in a 3GPP network, and further includes a data redundancy coding module, which is used in the MGC media gateway. After the controller negotiates with the MGW media gateway to determine the payload type of the connection message based on the ITU G711 protocol, the UP user plane protocol header is redundantly encoded into the required payload type, and is sent by the MGC media gateway controller to the MGW media gateway.

In this embodiment, the payload type determined by the IPBCP method is described.

For the manner in which IPBCP is used, the following embodiment uses the SDP protocol description as an example to illustrate a specific implementation.

m=audio $ RTP/AVP $

a=rtpmap:$ VND.3GPP.IU P/16000/1 a=Ptime: 5

Its meaning is: media notification = media format (audio) port number (selected by the media network port) transport protocol (RTP/AVP) media format (selected by the media gateway);

RTP/AVP - IETF uses the audio/video description of the real-time transport protocol carried over UDP. Media format - is the payload type defined in RTP/AVP;

Attribute = RTP mapping attribute: payload type (selected by the gateway) encoding type / clock frequency / encoding parameter;

Rtpmap - mapping attribute of rt V D.3GPRIUFP is a coding type used in 3GPP. 1600 is the clock frequency and is mono.

Attribute = packing time: duration

among them:

"m=,, the additional payload format defined in the field itself may also be a dynamic payload type, and once this is done, some additional attributes "a=" are needed to describe these dynamic load types.

To send a redundant stream, the sender has to know the recommended primary and second encoding. This information is explicit for the redundant format and is specified by using the additional attribute "fmtp", which conveys format-specific information. A session directory does not parse the value of the fmtp attribute, but simply forwards it. For redundancy, a list of format parameters for the RTP payload format is defined, separated by a slash " /,.

The RTP packet, as defined by the RTP audiovisual framework [3], can be as shown in Figure 3. Figure 3 is a diagram of the data packet defined by reference to the RTP audiovisual framework [3].

When sent, the MGW responds as:

m=audio 5432 RTP/AVP 100

a=rtpmap:100 V D.3GPP.IUFP/16000/1

a=Ptime: 5

The MGW selects the UDP port number and the payload type in the RTP mapping attribute to return to the MGC.

The MGC delivers the content selected by the MGW in the subsequent message sent to the MGW, and simultaneously carries the content. Bring the corresponding redundant codec type.

m=audio 5432 RTP/AVP 100 121

a=rtpmap:100 VND.3GPP.IUPP/16000/1

a=Ptime: 5

a=rtpmap:121 red/16000/1 (Description of redundant codec type) a=fmtp:121 100/100/100 (Description of redundancy mode)

The "rtpmap" attribute ij binds the payload type 121 to the codec "red", indicating that the codec is a redundant frame with a sampling rate of 16 kHz and is mono. When used in conjunction with SDP, the term "red" refers to the redundant format discussed in this article.

For implementations that do not use the IPBCP method:

m=audio $ RTP/AVP 121 100

a=rtpmap:100 VND.3GPP.IUFP/16000/1

a=Ptime: 5

a=rtpmap:121 red/16000/1

a=ftntp:121 100/100/100

At this time, the MGC directly informs the MGW to use the redundant codec mode, and delivers the payload type and redundancy mode information of the redundant codec.

It is apparent that those skilled in the art can make various modifications and variations to the invention without departing from the spirit and scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of the inventions

Claims

Rights request

A data redundancy sending method, comprising: the following steps:

(The media gateway controller sends the payload type required for the redundancy of the UP user plane protocol header to the media gateway according to the payload type required by the media gateway.

2. The method according to claim 1, wherein in step A, the media gateway controller negotiates a connection message payload type with the media gateway in real time.

The method according to claim 1, wherein the message in step A is a message of an ITU G711 coding scheme.

The method according to claim 1, wherein the media gateway controller and the media gateway negotiate to send a message by using an IP bearer control protocol.

5. The method according to claim 1, wherein the media gateway controller and the media gateway negotiate to send a message through a control plane.

6. The method of claim 1, wherein the redundant coding in step C is performed on a real-time transport protocol layer.

The method according to claim 1, wherein the number of redundancy of the UP user plane protocol header in step C is determined by the signaling plane through a corresponding network quality of service indicator.

The method according to claim 7, wherein the number of redundancy is two or three.

A data redundancy transmission system, comprising a media gateway controller and a media gateway, wherein the method further comprises:

The data redundancy coding module is configured to: after the media gateway controller negotiates with the media gateway to determine the payload type of the connection message based on the ITU G711 protocol, the UP user plane protocol header is redundantly coded into the required payload type, and the media gateway is configured by the media gateway. The controller sends to the media gateway.

10. The system according to claim 9, wherein the data redundancy coding module is located in a media gateway controller.