CN1413037A - Method for implementing facsimile service in mobile telecommunication system - Google Patents

Abstract

The method for implement facsimile service by utilizing universal mobile tele-communication system includes the following steps: using several facsimile processes to implement facsimile service in universal telecommunication system, the described several facsimile processes include wireless facsimile process, Internet protocol (IP) facsimile process and public switched telecommunication network (PSTN) facsimile process.

Description

A Method for Realizing Fax Service in Universal Mobile Telecommunication System

technical field

The present invention relates to a method for realizing facsimile service in Universal Mobile Telecommunications System (UMTS), more particularly to a method for realizing facsimile service in the Internet Protocol (IP) core network-based universal mobile telecommunication system.

Background technique

In the standard specification of 3GPP R4, fax is a mandatory telecommunication service for UMTS system. The UMTS fax service is implemented through the circuit domain. The signal generated by the fax device (FAX) is transmitted through the mobile terminal (MT), received by the radio access network (RAN) and transmitted to the mobile switching center/interworking function unit (MSC/IWF ), and then transmitted to the fax equipment (FAX) at the receiving end through the public land mobile network (PLMN), public switched telecommunication network (PSTN) or integrated services digital network (ISDN).

According to the 3GPP TS23.416 standard describing the implementation method of UMTS fax service, the implementation method of its fax service is: the fax packet message passes through Iu (Iu is the connection point between the UMTS radio access network and the core network, and is also regarded as A reference point) The protocol stack when the interface transmits to the core network Mobile Switching Center/Interworking Function Unit (MSC/IWF) is: Internet Fax Protocol/Fax User Datagram Protocol Transport Layer Protocol/User Datagram Protocol/Internet Protocol/ Point-to-Point Protocol/Layer 2 Relay Character-Oriented Protocol/Radio Link Protocol/Iu Interface User Plane Protocol/Asynchronous Transfer Mode Adaptation Layer Type 2 Protocol/Asynchronous Transfer Mode (IFP/UDPTL/UDP/IP/PPP/L2RCOP/RLP /IuUP/AAL2/ATM). Among them, the Internet Fax Protocol/Fax User Datagram Protocol Transport Layer Protocol (IFP/UDPTL) carries the fax image information, and is implemented based on the ITU-T-T.38 protocol, which is the same as the fixed-line Internet Protocol (IP) real-time fax protocol. The essential function of User Datagram Protocol/Internet Protocol/Point-to-Point Protocol (UDP/IP/PPP) is to carry Internet Fax Protocol (IFP), and it does not have the function of routing and forwarding. Its User Datagram Protocol (UDP) port number, IP Addresses etc. are meaningless. Layer 2 Relay Character Oriented Protocol/Radio Link Protocol (L2RCOP/RLP) is the radio link adaptation layer protocol; Iu UP is the user plane protocol of the Iu interface, asynchronous transfer mode adaptation layer type 2 protocol/asynchronous transfer mode (AAL2/ATM) is the bearer protocol of Iu UP. For MSC/IWF, it is necessary to realize the processing of all the above-mentioned protocol stacks, and convert the fax image information (ITU-T T.4 protocol description) carried in the IFP into the fax protocol of PSTN network (ITU-TT.30 protocol description), and supports various fax modem (MODEM) protocols (such as ITU-TV.17, V.29, V.27ter, V.21) to communicate with PSTN fax equipment through a time division multiple access (TDM) interface.

In the 3GPP R4 specification, the network structure has undergone great changes, and the core network can be based on IP transmission. Therefore, the above-mentioned traditional implementation method has brought many problems:

For the voice service, the mobile switching center/media gateway (MSC/MGW) of the end office only needs to export the IP interface, and the intercommunication with the PSTN can be converged to the mobile switching center/media gateway (GMSC/MGW) of the gateway office to complete, and the GMSC/MGW The MGW unifies the TDM interface to communicate with the PSTN. In order to realize the fax service, the MSC/MGW of the end office needs to realize all IWF functions, so the TDM interface must also be provided. In this way, in order to realize the fax service, the MSC/MGW of the end office needs two interfaces of IP and TDM, which increases the complexity of equipment implementation and the complexity of networking. In addition, compared with the IP interface, the density of the TDM interface is usually lower, which affects the integration degree of the equipment.

In order to realize the intercommunication of the fax service to the PSTN, the MSC/MGW of the end office needs to implement the MODEM protocol. Since the MODEM protocol usually needs to be implemented by a hardware MODEM chip, the implementation cost is relatively high.

Because the facsimile information is transformed into a 64K TDM signal at the MSC/MGW, the transmission efficiency is very low. Especially in the case of long-distance calls, the transmission costs are high.

In order to activate the fax service, large-scale coverage must be achieved, and a large number of end office MSCs/MGWs need to implement the fax IWF function. Moreover, because the user groups of the fax service are distributed unevenly, it is difficult to allocate network resources, and the above-mentioned contradiction is even more prominent.

In the traditional fax implementation method, each MSC/MGW of the end office needs to be connected to the PSTN through a TDM interface, and at the same time, an IP interface is also obtained to connect to the mobile switching center/media gateway (GMSC/MGW) of the gateway office to realize voice services, resulting in network The structure is very confusing.

Contents of the invention

On the premise of not increasing the overall implementation complexity, the present invention transmits the IP real-time fax protocol in the core network of the UMTS system by distributing the wireless fax protocol and sharing the IWF, and the gateway mobile switching center/media gateway (GMSC/MGW ) A method for realizing facsimile service in a universal mobile telecommunication system by uniformly outputting a TDM interface. It can simplify the network structure, rationally allocate resources, reduce implementation costs, and improve transmission efficiency. If the operator has fixed-line IP phone/IP fax (IP PHONE/IP FAX) services, it can conveniently form a joint network with the fixed-line IP FAX gateway to save long-distance transmission costs and provide more high-quality, low-cost fax business.

A method for realizing the fax service in the general telecommunication system of the present invention is realized through the following technical solutions, and the method includes the steps: realizing the fax service in the general telecommunication system through a plurality of facsimile processes, the multiple facsimile processes Includes wireless fax procedures, Internet Protocol (IP) fax procedures, and public switched telecommunications network (PSTN) fax procedures.

The wireless facsimile process includes the user unit (UE) loading the facsimile image signal into the Internet Fax Protocol (IFP), and layer 2 relay character-oriented protocol/radio link protocol/Iu interface user plane protocol/asynchronous transmission Mode Adaptation Layer Type 2 Protocol/Asynchronous Transfer Mode/Fax User Datagram Protocol Transport Layer Protocol/User Datagram Protocol/Internet Protocol/Point-to-Point Protocol (L2RCOP/RLP/IuUP/AAL2/ATM/UDPTL/UDP/IP/ PPP) together form a data packet sent to the Mobile Switching Center/Media Gateway (MSC/MGW), and the Layer 2 relay character-oriented protocol/wireless link in the data packet is sent by the Mobile Switching Center/Media Gateway (MSC/MGW) Protocol/Iu Interface User Plane Protocol/Asynchronous Transfer Mode Adaptation Layer Type 2 Protocol/Asynchronous Transfer Mode (L2RCOP/RLP/IuUP/AAL2/ATM) for processing.

Described Internet Protocol (IP) facsimile process is exactly that Mobile Switching Center/Media Gateway (MSC/MGW) will facsimile User Datagram Protocol Transport Layer Protocol/User Datagram Protocol/Internet Protocol/Point-to-Point Protocol (UDPTL/UDP/IP /PPP) to the gateway mobile switching center/media gateway (GMSC/MGW) for processing.

The described public switched telecommunications network (PSTN) facsimile process is to convert the facsimile image information carried by the IFP into the T.30 facsimile protocol on the PSTN network and send it to the third type of facsimile equipment (G3).

In the method adopted in the present invention, voice and facsimile services are uniformly carried, the end office MSC/MGW only needs to go out the IP interface, and the TDM interface is unified by the gateway office mobile switching center/media gateway (GMSC/MGW) to connect with the PSTN, and the network structure is more It is clear, optimizes the network structure, simplifies the equipment form, and simplifies the design of MSC/MGW, saves hardware cost, and makes the function distribution more reasonable.

Description of drawings

The substantive features and advantages of the method of the present invention will be further described below in conjunction with the accompanying drawings.

Fig. 1 is the network structural diagram that the facsimile service realizes;

Fig. 2 is a schematic diagram of a traditional implementation method of a facsimile service;

Fig. 3 is a schematic diagram of the implementation method of the facsimile service of the present invention;

Fig. 4 is the networking structural diagram of the traditional realization method of facsimile service;

Fig. 5 is a network structure diagram of the method for realizing the facsimile service of the present invention;

Fig. 6 is a list diagram of the hardware cost of the traditional implementation method of the fax service;

Fig. 7 is a list diagram of the hardware cost of the implementation method of the present invention;

Fig. 8 is a list diagram of the bandwidth statistics occupied by one fax of the method of the present invention;

FIG. 9 is a schematic diagram of implementing a fax service through a combined network of mobile and fixed networks.

Detailed ways

Fig. 1 is a network structural diagram for realizing the fax service. As shown in Figure 1, in the standard specification of 3GPP R4 of type 3 fax equipment (G3), fax is a mandatory telecommunication service for the UMTS system. The UMTS fax service is implemented through the circuit domain. The signal generated by the fax device (FAX) is transmitted through the mobile terminal (MT), received by the radio access network (RAN) and transmitted to the mobile switching center/interworking function unit (MSC/IWF ), and then transmitted to the fax equipment (FAX) at the receiving end through the public land mobile network (PLMN) or public switched telecommunication network (PSTN) or integrated services digital network (ISDN).

Fig. 2 is a schematic diagram of a traditional implementation method of a facsimile service. As shown in Figure 2, the figure is divided into upper and lower parts, the upper part is the network structure diagram, and the lower part is the corresponding protocol used by the part corresponding to the upper part. The protocol stack when the fax packet message is transmitted to the core network mobile switching center/interworking function unit (MSC/IWF) through the Iu interface is: Internet fax protocol/fax user data message protocol transport layer protocol/user data message protocol/Internet Protocol/Point-to-Point Protocol/Layer 2 Relay Character-Oriented Protocol/Radio Link Protocol/Iu Interface User Plane Protocol/Asynchronous Transfer Mode Adaptation Layer Type 2 Protocol/Asynchronous Transfer Mode (IFP/UDPTL/UDP/IP/PPP/L2RCOP /RLP/IuUP/AAL2/ATM). Among them, the Internet Fax Protocol/Fax User Datagram Protocol Transport Layer Protocol (IFP/UDPTL) carries the fax image information, and is implemented based on the ITU-T-T.38 protocol, which is the same as the fixed-line Internet Protocol (IP) real-time fax protocol. The essential function of User Datagram Protocol/Internet Protocol/Point-to-Point Protocol (UDP/IP/PPP) is to carry the Internet Fax Protocol (IFP), and it does not have the function of routing and forwarding, and its UDP port number and IP address are meaningless. Layer 2 Relay Character-Oriented Protocol/Radio Link Protocol (L2RCOP/RLP) is a radio link adaptation layer protocol; IuUP is a user plane protocol for the Iu interface, and Asynchronous Transfer Mode Adaptation Layer Type 2 Protocol/Asynchronous Transfer Mode ( AAL2/ATM) is the bearer protocol of Iu UP. For MSC/IWF, it is necessary to realize the processing of all the above-mentioned protocol stacks, and convert the fax image information carried in the IFP (ITU-TT.4 protocol description) into the PSTN network fax protocol (ITU-TT.30 protocol description ), and supports various fax modem (MODEM) protocols (such as ITU-TV.17, V.29, V.27ter, V.21) to communicate with PSTN fax equipment through the TDM interface. The meanings of the abbreviations in this figure are explained in the accompanying description of abbreviations.

Fig. 3 is a schematic diagram of the implementation method of the facsimile service of the present invention. In the common telecommunication system, a fax service is implemented through multiple fax processes, and the multiple fax processes include a wireless fax process, an Internet Protocol (IP) fax process, and a public switched telecommunications network (PSTN) fax process. The wireless facsimile process includes the user unit (UE) loading the facsimile image signal into the Internet Fax Protocol (IFP), and layer 2 relay character-oriented protocol/radio link protocol/Iu interface user plane protocol/asynchronous transmission Mode Adaptation Layer Type 2 Protocol/Asynchronous Transfer Mode/Fax User Datagram Protocol Transport Layer Protocol/User Datagram Protocol/Internet Protocol/Point-to-Point Protocol (L2RCOP/RLP/IuUP/AAL2/ATM/UDPTL/UDP/IP/ PPP) together form a data packet sent to the Mobile Switching Center/Media Gateway (MSC/MGW), and the Layer 2 relay character-oriented protocol/wireless link in the data packet is sent by the Mobile Switching Center/Media Gateway (MSC/MGW) Protocol/Iu Interface User Plane Protocol/Asynchronous Transfer Mode Adaptation Layer Type 2 Protocol/Asynchronous Transfer Mode (L2RCOP/RLP/IuUP/AAL2/ATM) for processing. Described Internet Protocol (IP) facsimile process is exactly that Mobile Switching Center/Media Gateway (MSC/MGW) will facsimile User Datagram Protocol Transport Layer Protocol/User Datagram Protocol/Internet Protocol/Point-to-Point Protocol (UDPTL/UDP/IP /PPP) to the gateway mobile switching center/media gateway (GMSC/MGW) for processing. The described public switched telecommunications network (PSTN) facsimile process is to convert the facsimile image information carried by the IFP into the T.30 facsimile protocol on the PSTN network and send it to the third type of facsimile equipment (G3).

As shown in Figure 3, the figure is divided into upper, middle, and lower parts. The upper part is the network structure diagram, the middle part is the corresponding protocol used by the part corresponding to the upper part, and the lower part represents the network structure diagram corresponding to the upper part. The corresponding fax process used by the corresponding part, that is, the wireless fax process, the IP fax process and the PSTN fax process. The invention adopts the method of realizing the wireless facsimile protocol in a distributed manner and sharing the IWF. On the MSC/MGW of the end office, only the protocol related to the Iu interface and the wireless link layer protocol are processed, that is, the L2RCOP/RLP/IuUP/AAL2/ATM protocol is terminated on the MSC/MGW, and the above IFP/UDPTL/UDP/IP The /PPP protocol is regarded as forwarding to the IP core network, and communicates with the GMSC/MGW through the IP fax process. It is worth pointing out that the IP fax protocol does not specify layer 2 technology, so when forwarding the IP FAX protocol on the IP core network, it is not necessary to use the PPP protocol, so the PPP protocol can also be terminated on the MSC/MGW and not forwarded to IP core network (in the following part of this article, only the forwarding of PPP on the IP core network is used as an example). Realize the IWF function on the GMSC/MGW and output the TDM interface, convert the fax image information carried by the IFP into the T.30 fax protocol on the PSTN network, and equip a processor that implements the MODEM protocol to realize the fax MODEM function, and G3 fax on the PSTN machine communication. Distributed implementation of wireless fax protocol, processing L2RCOP/RLP/IuUP/AAL2/ATM protocol on MSC/MGW close to RAN; conversion of fax service to PSTN on GMGW/MSC; between MSC/MGW and GMGW/MSC via T .38 protocol defined IP FAX process communication. At the same time, the MGW/MSC can also communicate with the fixed network IP FAX gateway, and realize the mobile fax service in conjunction with the 3G mobile network and the fixed IP phone/fax network.

FIG. 4 is a network structure diagram of a traditional method for implementing a fax service. As shown in Figure 4, in the traditional implementation method of the fax service, each MSC/MGW needs to connect to the PSTN through a TDM interface, and at the same time, it also needs to connect an IP interface to the GMSC/MGW to realize the voice service, resulting in a very confusing network structure.

Fig. 5 is a network structure diagram of the method for realizing the fax service of the present invention. As shown in Fig. 5, in the method adopted in the present invention, the voice and fax services are unifiedly carried, and the MSC/MGW only needs to output the IP interface, and the GMSC/MGW uniformly outputs the TDM interface to connect with the PSTN. The network structure is clearer, the function distribution is more reasonable, and the design of MSC/MGW is simplified. According to the method of the present invention, on the MSC/MGW close to the RAN, only the L2RCOP/RLP/IuUP/AAL2/ATM protocol is terminated, and the IFP/UDPTL/UDP/IP/PPP is forwarded to the IP core network, through the standard IP FAX process (T.38 protocol regulation) communicates with GMSC/MGW. Realize the IWF function on the GMSC/MGW, convert the fax image information carried by the IFP into the T.30 fax protocol on the PSTN network, equip the MODEM chip to realize the fax MODEM function, and communicate with the G3 fax machine on the PSTN.

Fig. 6 is a tabular diagram of hardware costs of the conventional implementation method of the fax service and Fig. 7 is a tabular diagram of the hardware cost of the implementation method of the present invention. As shown in Figures 6 and 7, due to the traditional implementation method, each MSC/MGW must be equipped with a processor that implements the fax MODEM protocol chip, and because the distribution of fax service user groups is uneven and fluctuates greatly, this decentralized configuration Will cause waste. The present invention centrally configures MODEM chips on the GMSC/MGW, which can be shared and used by multiple MSCs/MGWs, and the resources are used reasonably. Comparing the cost estimates in the above two tables, it can be seen that the cost of the method of the present invention is only 60% of that of the traditional method, thus saving the cost of hardware.

Fig. 8 is a tabular diagram of bandwidth statistics occupied by one fax in the method of the present invention. As shown in Fig. 8, the bandwidth of 64Kbit/s is needed for the one-way fax channel of the traditional implementation method; and the bandwidth occupied by one-way fax of the method of the present invention is occupied by 60ms/packet, in fact, one-way fax takes up 16kbps, which is only 1/2 of the traditional implementation method 4. Therefore, transmission resources are saved.

FIG. 9 is a schematic diagram of implementing a fax service through a combined network of mobile and fixed networks. As shown in Figure 9, for an operator that develops 3G mobile and IP phone/fax network services at the same time, it can conveniently combine 3G mobile network and fixed IP network to carry out IP fax service. For local calls, it can be connected to PSTN through local GMSC/MGW; for long-distance calls, it can be connected to local fixed network IPFAX gateway through IP backbone network, and connected to PSTN. At present, all mainstream operators in China, such as China Telecom, China Mobile, China Unicom, China Netcom, Jitong and Railcom, have opened IP phone/fax services and achieved large-scale nationwide coverage. Therefore, this 3G mobile and IP phone/fax joint networking method can borrow existing resources to achieve large-area coverage, save long-distance relay fees, and provide more attractive fax services. Therefore, adopting the method of the present invention is convenient for operators to form a network. Attachment: Description of abbreviations 1.UMTS: Universal Mobile Telecommunications System 2.FAX: Fax Equipment 3.MT: Mobile Terminal 4.RAN: Radio Access Network 5.MSC: Mobile Switching Center 6.IWF: Interworking Functional Unit 7.PLMN : Public Land Mobile Network 8.PSTN: Public Switched Telecommunications Network 9.ISDN: Integrated Services Digital Network 10.TAF: Terminal Adaptation Function 11.TE: Terminal Equipment 12.MODEM: Modem 13.MGW: Media Gateway 14. GMSC/MGW: Gateway Mobile Switching Center/Media Gateway 15.G3: Class 3 Fax Equipment 16.UDPTL: Fax User Datagram Protocol Transport Layer Protocol 17.UDP: User Datagram Protocol 18.IP: Internet Protocol 19 .PPP.: Point-to-Point Protocol 20.RTP: Real-Time Transport Protocol 21.AAL2: Asynchronous Transfer Mode Adaptation Layer Type 2 Protocol 22.E-T.38: Enhanced T.38 Protocol 23.IFP: Internet Fax Protocol 24.L2RCOP: 2 Layer Relay Character-Oriented Protocol 25. R-FA: Receiver Fax Adapter 26. RLC: Radio Link Control 27. RLP: Radio Link Protocol 28. R-TAF: Receiver Terminal Adaptation Function 29. T-FA : Transmitter fax adapter 30.T-TAF: Transmitter terminal adaptation function 31.2W: Second line 32.MAC: Media access control 33.CDMA: Code division multiple access 34.CONTP: Character-oriented non-transparent protocol 35.I /FCCT: circuit interface

Claims (4)

1, a kind of method that in Universal Mobile Telecommunications System, realizes facsimile service, it is characterized in that: the method comprising the steps of:

Realize facsimile service by a plurality of fax flow processs in generic telecommunications system, described a plurality of fax flow processs comprise radio facsimile flow process, Internet Protocol (IP) fax flow process and Public Switched Telephone Network (PSTN) fax flow process.

2, method according to claim 1, it is characterized in that: described radio facsimile flow process comprises that subscriber unit (UE) is loaded into the facsimile chart picture signals in the Internet Facsimile Protocol (IFP), form packet with the character-oriented agreement/radio link protocol of layer 2 relay/Iu User Plane agreement/adapting layer types of asynchronous transfer mode 2 agreements/asynchronous transfer mode/fax user datagram protocol transport layer protocol/user datagram protocol/Internet Protocol/point-to-point protocol (L2RCOP/RLP/IuUP/AAL2/ATM/UDPTL/UDP/IP/PPP) and send to mobile switching centre/media gateway (MSC/MGW), and the character-oriented agreement/radio link protocol of the layer 2 relay in the packet/Iu User Plane agreement/adapting layer types of asynchronous transfer mode 2 agreements/asynchronous transfer mode (L2RCOP/RLP/IuUP/AAL2/ATM) is handled by mobile switching centre/media gateway (MSC/MGW).

3, method according to claim 2 is characterized in that: described Internet Protocol (IP) fax flow process is exactly that mobile switching centre/media gateway (MSC/MGW) user datagram protocol transport layer protocol/user datagram protocol/Internet Protocol/point-to-point protocol (UDPTL/UDP/IP/PPP) of will faxing sends to gateway exchange mobile switching centre/media gateway (GMSC/MGW) and handles.

4, method according to claim 3 is characterized in that: described Public Switched Telephone Network (PSTN) fax flow process is exactly that the facsimile chart image information that IFP carries is converted to the online T.30 facsimile protocol of PSTN and sends to Group-3 fax equipment (G3).

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