CN101166300B - Service switching method and system - Google Patents

Abstract

The method for switching services includes steps: step S102, in procedure of voice call, when receiving signal tone for switching services from equipment at called user, the mobile station at the called party carries out service negotiation and hard switching through the base station controller at the called party to establish connection to network intercommunication function unit (NIFU) at the called party; step S106, through receiving in-band message, the base station controller at calling party starts switching services, establishes connection between the calling party and NIFU at the calling party so as to complete switching services. The invention also discloses the system for switching services. The invention also discloses another method and system for switching services. Without changing habit user uses, the invention implements function for switching IWF services between voice service and facsimile service so as to be convenient for user to do operations.

Description

Service switching method and system

technical field

The present invention relates to the communication field, and more particularly relates to a service switching method and system.

Background technique

The Interworking Function (IWF for short) is a device in the wireless network, which supports the circuit domain data service interworking function of the wireless network and other networks (such as PSTN, ISDN, Internet, and other PLMNs), and uses asynchronous data Perform services such as remote access, Email access, Intranet access, ISP access, public database retrieval, and interconnection of two data terminals.

According to the location of IWF resources, IWF can be divided into CDMA Interworking Function (CIWF for short) and Shared Interworking Function (SIWF for short). Among them, CIWF is the IWF function based on the base station controller (Base Station Controller, referred to as BSC), and the IWF device is connected to the BSC; SIWF is based on the IWF function of the Mobile Switch Center (MSC), and the IWF device is connected to the MSC. . Figure 1 and Figure 2 are the networking diagrams of CIWF and SIWF respectively.

At present, the IWF is mainly used for fax services. In the CDMA mobile communication system, the fax service mainly adopts the direct fax method, that is, the calling party enters a special prefix and the called user number, and the network side directly establishes a fax service call. In practical applications, there is a need to perform voice services first and then fax services. The main reasons are:

1) In the same call, it is impossible to notify the other party in advance to prepare for receiving faxes, and the other party's fax machine does not necessarily support automatic faxing;

2) If it is set to direct fax, the number and fax machine can only be used for fax business. If you want to make a phone call, you need to reset it.

3) The previous method can no longer be used after port A becomes IP. Before the A port was IP-based, it was carried by Time Division Multiplexing (TDM for short), and the BSC had a Transcoder (TC for short) resource to detect the fax signal tone on the core network side. After the port A becomes IP-based, the TC resources are moved up to the MSC core network, and there are no TC detection resources in the BSC, which cannot detect the fax signal when the voice is switched to fax; the BSC forwards the wireless side message to the Media Gateway (MGW for short); In addition, when the Transcoder FreeOperation (Transcoder FreeOperation) TrFO/Remote Transcoder Operation (Remote Transcoder Operation, RTO for short) is activated, there is no TC resource in the voice channel or the TC resource is not in the end office, The end office may not be able to detect, that is to say, in the case of TrFO, the MGW cannot detect the fax signal sent by the fax machine when the voice is switched to fax because there is no TC resource. Abbreviated as MS), there is no place to test. Therefore, previous business processes need to be changed.

Under the separation architecture, the MSC is divided into an MGC and an MGW. Figure 3 shows a schematic structural diagram of the MSC under the separation architecture.

The voice service has been switched to the fax service in the fixed communication network. The method is: the calling user dials the PSTN number of the called fax, and after the call is connected, the calling user informs the called user that he needs a fax, and the called user sends the fax on the fax machine Control signal, after receiving the fax control signal, the calling side presses the fax send key to send the fax, completing a voice-to-fax service switching process.

Since most fixed stations currently do not support IWF service negotiation initiated by the calling side, in the original TDM case, it is necessary to rely on the TC on the BSC side to detect the CED signal from the called party, so as to initiate the IWF service change process of the calling party. After the port A becomes IP-based, the switching of the voice and fax service is realized through the solution of the prior art 1, as follows:

In the case that the calling party of the fixed station cannot initiate service change, the user can initiate a FLASH operation (flashing) to initiate a FAX negotiation through out-of-band dialing, and BSC and MSC are required to support this out-of-band negotiation process.

By pressing the Flash key: [Flash key: There is a key called Flash key on the fax machine, and the function of this key is similar to that of a hook. Because the duration of normal hook-flash is uncertain, a relatively standard hook-flash time can be generated through the Flash button. Flashing the hook means that the phone hangs up for a short time during a call, and then goes off the hook. ]

After the A port is IP-based, the IP-BSC cannot detect the CED signal of the fax, and the calling MS cannot automatically complete the voice-to-fax handover. The current design for switching from voice to fax is to configure the flash prefix on the MGC and manually switch the flash from voice to fax. The current test found that this solution has the following two fatal flaws:

1) The operation does not conform to the habit:

After the voice is connected, when switching to the fax service, the called party can complete the voice-to-fax switching; the calling user must manually press the flash prefix + flash key + send to manually switch (if the fax machine does not have a flash key, you can only press the Fork switching), the customer operability of this scheme is poor.

2) The timing of manual switching is very difficult to grasp:

If the calling party switches manually too early, the calling party will release the fax service without waiting for the called DIS fax signal. If the switch is too late, the called party will release the fax service if they cannot wait for the calling party's DCS fax signal. After testing dozens of times in the laboratory and looking for the time point of switching, only a few times can be successfully switched, so the success rate is very low. However, DIS and DCS messages are different for different fixed stations and facsimile machines, so the actual commercial use is certainly impossible.

In the second prior art, the voice-fax switching method is supported through the extension mode of the signaling plane. Here, by changing the codec message to carry the IWF service information, the BSC switches its codec to the corresponding codec of the IWF. The BSC initiates the process of notifying the MS of service switching, and then notifies the MSC of the switching request, and then the MSC inserts the IWF. This method can be applied to CDMA IP-based networks, including A-port IP-based and core network IP-based.

It mainly includes the synthesis of the following processes: air interface service negotiation process and hard handover process, bearer handover process between MGCs, and codec handover (service handover) process.

The second prior art needs to extend the signaling plane and introduce the extension of the SDP. The message content between MSC and BS needs to be extended.

Contents of the invention

The purpose of the present invention is, in the mobile communication system, such as in the CDMA mobile communication system, after the A port is changed to IP, realize the switching function of the voice service to the IWF service of the fax service, and can make the user unable to perceive the change of the network, so The invention provides a service switching method and system.

According to one aspect of the present invention, a service switching method is proposed. The method includes: step S102, during the voice call, when the called party mobile station receives the service switching signal tone of the called user equipment, it performs service negotiation and hard handover through the called party base station controller, and establishes the called party The connection with the network interworking functional unit; step S106, the calling party base station controller starts service switching by receiving the in-band message, establishes the connection between the calling party and the calling party network interworking functional unit, and completes the service switching; When both the calling party and the called party have respectively established connections to the calling party/called party network interworking functional unit, when the calling party and the called party are at the same end During office hours, the media gateway controller of the called party and/or the calling party, according to the service request received from the base station controller of the called party and/or the calling party or the media gateway of the called party and/or the calling party message to determine the direction of the fax; and when the calling party and the called party are in different end offices, the called party and/or the calling party media gateway controller according to whether the calling party and/or Or the service request message of the called party determines the fax sender.

In the above service switching method, between step S102 and step S106, including: step S104, the called party MSC initiates a bearer switch request to the calling party MSC, and the calling party MSC performs the bearer switch.

Optionally, in the above-mentioned service switching method, step S106 includes the following steps: the base station controller of the calling party judges the calling and called direction of the fax by receiving the in-band message, and sends a switching request message to the mobile switching center of the calling party; The called party's mobile switching center initiates a bearer switching request to the calling party's mobile switching center, and the calling party's mobile switching center performs the bearer switching; and, after receiving a response from the calling party's mobile switching center, the calling party's base station controller begins to perform Service switching, establishing the connection between the calling party and the calling party's network interworking functional unit, and completing the service switching.

In the above service switching method, step S102 further includes the following steps: before the network interworking function unit of the called party is activated, the base station controller of the called party forms the CED fax tone message sent by the mobile station of the called party into a message, Send it to the called party's mobile switching center through the media layer; or, after the called party's network interworking function unit is activated, the media gateway will send the fax tone sent by the called party's network interworking function unit into a message and send it to the calling party's base station controller.

In the above service switching method, the packet is at least one of 2833/ced, 2833/v21flag, and 2833/cng.

In the above service switching method, in step S104, by describing the bearer information required by the fax in the bearer switching, it is indicated to switch to the bearer type suitable for the fax service, which at least includes the following description method: in the description of the extended session description protocol Attribute description, using the description in the V152 protocol, and adding a private description in the description of the extended session description protocol.

In the above service switching method, step S106 includes: step S1062, after receiving the bearer switching request, the calling party's mobile switching center switches the bearer; step S1064, the calling party's base station controller Calling direction, send switching request message to calling party mobile switching center; The connection of the network interworking functional unit completes the service switching.

According to another aspect of the present invention, a service switching system is provided, the system includes: a called party connection establishment device, located at the called party side, used for, during a voice call, when the called party mobile station receives the When calling the user equipment’s service switching signal tone, the base station controller of the called party performs service negotiation and hard handover, and establishes the connection between the called party and the network interworking function unit of the called party; The calling party side is used to enable the calling party base station controller to start service switching by receiving an in-band message, establish a connection between the calling party and the calling party network interworking functional unit, and complete the service switching; and/or the called party has established a connection to the calling party/called party network interworking functional unit, when the calling party and the called party are in the same end office, the called party And/or the media gateway controller of the calling party judges the fax direction according to the service request message received from the base station controller of the called party and/or the called party or the media gateway of the called party and/or the calling party; and when the When the calling party and the called party are in different end offices, the media gateway controller of the called party and/or the calling party The request message identifies the sender of the fax.

In the above service switching system, it includes: a bearer switching request initiating device, located between the calling party and the called party, for making the mobile switching center of the called party initiate a bearer switching request to the mobile switching center of the calling party, and the calling party The mobile switching center performs bearer switching.

Optionally, in the above-mentioned service switching system, the device for establishing the connection of the calling party includes: a service triggering module of the calling party, which is used to enable the base station controller of the calling party to judge the direction of the calling party and the called party of the fax by receiving an in-band message, and send The calling party's mobile switching center sends a service switching request; the calling party's bearer switching request initiation module is used to make the called party's mobile switching center initiate the calling party's mobile switching center after the calling party's base station controller triggers the service switching process bearer switch request, the calling party mobile switching center performs bearer switch; The connection between the calling party and the calling party's network interworking functional unit completes the service switching.

In the above service switching system, the called party connection establishment device further includes: a base station controller message sending module, which is used to make the called party base station controller send the mobile station over before the called party network interworking function unit is activated. The CED fax tone message is sent to the called party's mobile switching center through the media layer; or, the media gateway message sending module is used to enable the media gateway to send the called party's The facsimile tone sent by the network interworking function unit is converted into a message and sent to the base station controller of the calling party.

In the above service switching system, the base station controller of the calling party receives at least one of the following messages: 2833/ced, 2833/v21flag, and 2833/cng.

In the above service switching system, the caller bearer switching request initiation device indicates switching to a bearer type suitable for the fax service by describing the corresponding bearer information required by the fax in the bearer switching, which at least includes the following description method: extending the session Describe the attribute description in the protocol description, adopt the description in the V152 protocol, and add a private description in the extended session description protocol description.

In the above service switching system, the calling party connection establishment device includes: the calling party bearer switching request module, which is used to switch the bearer after the calling party mobile switching center receives the bearer switching request; the calling party service trigger module uses It is used to enable the calling party base station controller to judge the calling and called direction of the fax by receiving the in-band message, and send a service switching request to the calling party mobile switching center; and the calling party service switching module is used to control After receiving the response from the mobile switching center of the calling party, the device starts to switch the service, establishes the connection between the calling party and the network interworking function unit of the calling party, and completes the service switching.

The present invention also provides another service switching method, including: step S702, during the voice call, when the called party mobile station receives the service switching signal tone of the called user equipment, the called party base station controller performs Service negotiation and hard handover, establishing the connection between the called party and the network interworking functional unit of the called party; step S704, the calling party's mobile switching center and the called party's mobile switching center perform bearer switching, and when the switching is completed and the called party's network is activated After the interworking function unit, the base station controller of the called party inserts the codec resource to detect the fax tone signal of the IP side; and step S706, after the base station controller of the calling party detects the fax tone signal of the IP side, the base station controller of the calling party Initiate service switching, establish the connection between the calling party and the calling party network interworking function unit, and complete the service switching.

The present invention also provides another service switching system, including: a called party connection establishment device, located at the called party side, used for when the called party's mobile station receives a service switching request from the called user equipment during a voice call. In case of signal tone, business negotiation and hard handover are performed through the base station controller of the called party, and the connection between the called party and the network interworking functional unit of the called party is established; the fax tone signal detection device on the IP side is used for the calling party and the called party The mobile switching center performs bearer switching. After the switching is completed and the network interworking function unit of the called party is activated, the base station controller of the called party inserts codec resources to detect the fax tone signal on the IP side; and the connection establishment device of the calling party is located in the On the party side, when the base station controller of the calling party detects the fax tone signal on the IP side, the base station controller of the calling party initiates service switching, establishes the connection between the calling party and the network interworking functional unit of the calling party, and completes the Business switching.

Through the present invention, in the CDMA mobile communication environment, in the case of IP-based A port or IP-based core network, the switching function of the IWF service from the voice service to the fax service is realized, and the user's usage habits are not changed, which greatly facilitates user action.

Description of drawings

The accompanying drawings described here are used to provide a further understanding of the present invention and constitute a part of the application. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations to the present invention. In the attached picture:

Fig. 1 is a block diagram showing the CIWF networking structure;

Fig. 2 is a block diagram showing the SIWF networking structure;

Figure 3 shows a schematic structural diagram of MSC under the separation architecture;

Fig. 4 is a flowchart illustrating a service switching method according to the present invention;

Fig. 5 is a flowchart showing a service switching method of a specific embodiment of the present invention;

Fig. 6 is a block diagram showing a service switching system according to the present invention;

Fig. 7 is a flowchart illustrating another service switching method according to the present invention; and

Fig. 8 is a block diagram showing another service switching system according to the present invention.

Detailed ways

The specific implementation manners of the present invention will be described in detail below with reference to the accompanying drawings.

Referring to Fig. 4, the service switching method according to the present invention is illustrated. The method includes: step S102. During the voice call, when the called party mobile station receives the service switching signal tone of the called user equipment, it performs service negotiation and hard handover through the base station controller of the called party, and establishes the called The connection between the party and the network interworking functional unit; and step S106, the calling party's base station controller starts service switching by receiving the in-band message, establishes the connection between the calling party and the calling party's network interworking functional unit, and completes the service switching .

Wherein, between step S102 and step S106, including: step S104, the called party MSC initiates a bearer switching request to the calling party MSC, and the calling party MSC performs bearer switching.

Optionally, step S106 includes the following steps: the base station controller of the calling party judges the calling and called direction of the fax by receiving the in-band message, and sends a switching request message to the calling party's mobile switching center; The calling party's mobile switching center initiates a bearer switching request, and the calling party's mobile switching center performs bearer switching; The connection with the network interworking function unit of the calling party completes the service switching.

Wherein, step S102 further includes the following steps: before the network interworking function unit of the called party is activated, the base station controller of the called party forms a fax tone message such as CED sent by the mobile station of the called party into a message, and sends it through the media layer to the mobile switching center of the called party; or, after the network interworking function unit of the called party is activated, the media gateway converts the fax tone sent by the network interworking function unit into a message and sends it to the base station controller of the calling party.

Wherein, the packet is at least one of 2833/ced, 2833/v21flag, and 2833/cng.

Wherein, in step S104, by describing the corresponding bearer information required by fax in the bearer switch, it is indicated to switch to the bearer type suitable for the fax service, which at least includes the following description methods: attribute description in the extended session description protocol description, using The description in the V152 protocol and the private description added in the description of the extended session description protocol.

Wherein, step S106 includes the following steps: step S1062, after receiving the bearer switching request, the calling party's mobile switching center switches the bearer; step S1064, the calling party's base station controller judges the calling and called direction of the fax by receiving the inband message, Send a handover request message to the calling party's mobile switching center; and step S1066, after the calling party's base station controller receives the response from the calling party's mobile switching center, it starts to perform service switching, and establishes the network interworking function between the calling party and the calling party Unit connection to complete service switching.

Among them, in the case that both the calling party and the called party have respectively established connections to the calling party/called party network interworking functional unit: when the calling party and the called party are in the same end office, the called party and the called party /or the media gateway controller of the calling party judges the fax direction according to the service request message received from the base station controller of the called party and/or the calling party or the media gateway of the called party and/or the calling party; and when the calling party When the party and the called party are in different end offices, the media gateway controller of the called party and/or the calling party determines the fax sender according to whether the service request message of the calling party and/or the called party is received.

A specific embodiment of the present invention will be described below with reference to FIG. 5 . Figure 5 is a flow diagram of the BSC triggering the handover process by detecting the 2833/CED tone to realize the voice-to-IWF service handover, including the following steps:

Both parties are in a voice call:

1) The called party MS receives the CED tone sent by the fax machine, recognizes that the voice service needs to switch the fax service, sends a message to the called BSC to notify the detection of the fax tone, and requests service switching;

2) The called MS notifies the BS that the CED tone is detected, and requests service switching;

3) The called BS receives the service switching message sent by the called MS, recognizes that the voice service needs to switch to the fax service, and responds to the service switching response message;

4) The called BS sends a Service Request (service request) message to the called MS to initiate a service negotiation process;

5) The called MS sends a Service Response message to the called BS to accept the fax data service option;

6) The called BS sends a HandoffRequired (handover request) message to the called MSC, and initiates a hard handover process. The target cell is the current active set, and the service option is fax data service;

7) The called MSC completes the relevant processing, and sends a HANDOFFREQUEST response message to the same called BS;

8) The called BS types the fax tone messages such as CED sent by the called MS into a 2833/CED message and sends it to the called MSC through the media layer; or after the called IWF is activated, the fax tone sent by the called IWF is sent by The MGW sends a 2833/ced|V21flag message to the BS. See step (27) (the called MS completes the service plane signaling interaction between the voice-to-fax handover between the called BS and the called IWF through the called BS);

9) The called MSC completes the establishment of the service path to the called IWF network element;

10) The called MSC initiates a bearer switching request to the calling MSC;

11) The calling MSC waits for the calling BSC to initiate a handover request;

12) When the calling BS receives the 2833/CED message, it thinks that it has received the corresponding fax tone from the media layer, judges the calling and calling direction of the fax, and triggers it to start the service switching process;

13) The calling BS initiates a service switching request to the calling MS;

14) The calling MS responds to the calling BS service switching request response;

15) The calling BS sends a Handoff Required message to the MSC, initiates a hard handover process, the target cell is the current active set, and the service option is fax data service;

16) The calling MSC responds to the handover request response;

17) Continue to describe the calling situation below: the calling BS returns a HandoffRequest Ack message to the calling MSC;

18) The calling MSC sends a Handoff Command message to the calling BS; (the follow-up is to describe the calling situation);

19) The calling BS sends a UHDM message to the calling MS, carrying a fax service configuration record;

20) The calling MS returns a confirmation message to the calling BS;

21) The calling BS sends a Handoff Commenced message to the calling MSC to notify the MSC that the mobile station starts switching;

22) The calling MS successfully switches to the target traffic channel, and sends a HandoffCompletion message to the calling BS;

23) The calling BS sends a HandoffComplete message to the calling MSC;

24) The calling MSC sends a Clear Command to the calling BS to release the source side;

25) The calling BS sends a Clear Complete message to the calling MSC after releasing the source side;

26) The calling MS completes the service plane signaling interaction of the voice-to-fax handover between the calling IWF and the calling IWF through the calling BS;

27) After both the calling and called parties complete the signaling interaction on the service plane to the IWF, the calling and called MSs enter the fax service data transmission state.

The present invention is aimed at the bearer switching in the core network, wherein, in the bearer switching, the corresponding bearer information required by the fax is described to indicate switching to the bearer type suitable for the fax service, and the description method is as follows:

1. Extend the attribute description a=fax in the SDP description or adopt the description in the V152 protocol:

This method is the existing NGN technology, which is not applied in CDMA network. In order to be compatible with the intercommunication between CDMA network and NGN, the same description method as NGN is adopted.

m=audio 3456RTP/AVP 98

a=fax

Or the description in the V152 protocol

m=audio 3456RTP/AVP 98

a=rtpmap:98PCMU/8000

a=gpmd:98vbd=yes

2. In the extended SDP description, add a private description:

m=audio 3456RTP/AVP 98

a=fax,

a=fmtp:98CED or a=fmtp:98CNG or a=fmtp:98V21flag

m=audio 3456RTP/AVP 98

a=rtpmap:98PCMU/8000

a=gpmd:98vbd=yes

a=fmtp:98CED or a=fmtp:98CNG or a=fmtp:98V21flag

Method: By extending the description of SDP, fmtp is described in the SDP protocol as follows:

Attribute = fmtp: format Format specific parameters

By defining CED, CNG, and V21flag in the specific parameters, the corresponding detected fax signals are indicated between the MGCs, and the peer office judges whether it is the fax calling party or the called party. Among them, CNG: refers to the fax calling party; CED: refers to the fax called party; V21flag: refers to the first detected fax calling party. For the following properties:

a＝fmtp:<format><format specific parameters>

This attribute allows format specific parameters to be passed in a way that the SDP does not understand. The format (format) must be specified in the media description (m=).

It can be seen that, for the MGC to notify the BSC to perform service switching, the present invention extends the existing codec switching process.

When the core network receives the instruction of the fax service, it can notify the calling end office to switch the service. See the above for the notification method. When the end office MSC receives the service switching request, it first switches the bearer, and then waits for the calling BSC to perform service switching (switching to the fax service state). After receiving the in-band 2833/CED or 2833/V21flag message, the BSC notifies the MSC to perform service switching, and notifies the MS to perform service switching. The subsequent process is the same as that when the A port is a TDM interface.

Processing of fax direction when MGC activates IWF: For intra-office, MGC can know the fax direction according to the signal reported by BSC/MGW; for inter-office, end-office MGC can determine the fax sender according to the detected fax signal reported by BS.

Referring to Fig. 6, the service switching system according to the present invention will be described below. The system includes: a called party connection establishment device 610, located at the called party side, used for, during a voice call, when the called party mobile station receives the service switching signal tone of the called user equipment, through the called party's The base station controller performs service negotiation and hard handover, and establishes a connection between the called party and the called party's network interworking functional unit; Receive the in-band message to start service switching, establish the connection between the calling party and the network interworking functional unit of the calling party, and complete the service switching.

Wherein, the above-mentioned service switching system includes: a bearer switching request initiation device (not shown), located between the calling party and the called party, for making the called party's mobile switching center initiate the bearer switching center to the calling party's mobile switching center request, the calling party's mobile switching center performs bearer switching.

Optionally, the calling party connection establishment device 620 includes: a calling party service trigger module (not shown), which is used to enable the calling party base station controller to judge the direction of the fax calling and calling party by receiving the inband message, and send The calling party's mobile switching center performs a service switching request; the calling party's bearer switching request initiation module (not shown), is used to make the called party's mobile switching center send the calling party's mobile switching center to the calling party after the calling party's base station controller triggers the service switching process The mobile switching center of the calling party initiates a bearer switching request, and the mobile switching center of the calling party performs the switching of the bearer; After answering, start to switch the service, establish the connection between the calling party and the network interworking function unit of the calling party, and complete the service switching.

Wherein, the called party connection establishment device 610 further includes: a base station controller message sending module (not shown), which is used to make the called party base station controller send the mobile station message before the called party network interworking function unit is activated. Facsimile tone messages such as CED that come over are marked into messages and sent to the called party's mobile switching center through the media layer; or the media gateway message sending module (not shown), is used to use The media gateway converts the fax tone sent by the network interworking function unit into a message and sends it to the base station controller of the calling party.

Wherein, the base station controller of the calling party receives at least one of the following messages: 2833/ced, 2833/v21flag, and 2833/cng.

Wherein, the calling party bearer switching request initiating device indicates to switch to the bearer type suitable for the fax service by describing the corresponding bearer information required by the fax in the bearer switching, which at least includes the following description method: in the description of the extended session description protocol Attribute description, using the description in the V152 protocol, and adding a private description in the description of the extended session description protocol.

Optionally, the calling party connection establishment device 620 includes: a calling party bearer switching request module (not shown), which is used to switch the bearer after the calling party mobile switching center receives the bearer switching request; Module (not shown), is used to make the calling party's base station controller judge the calling and called direction of the fax by receiving the in-band message, and perform a service switching request to the calling party's mobile switching center; and the calling party's service switching module ( not shown), used to start service switching after the calling party’s base station controller receives the response from the calling party’s mobile switching center, establish a connection between the calling party and the calling party’s network interworking functional unit, and complete the service switching.

Wherein, when both the calling party and/called party have established connections to the calling party/called party network interworking functional unit, when the calling party and the called party are in the same end office, the called party and the called party / or the calling party media gateway controller judges the fax direction according to the service request message received from the called party and / or the called party base station controller or the called party and / or the calling party media gateway; and when the calling party and When the called party is in different end offices, the media gateway controller of the called party and/or the calling party determines the fax sender according to whether the service request message of the calling party and/or the called party is received.

It can be seen from the above that during the voice call, the calling user notifies the called user to send a fax control signal on the terminal equipment (TE), that is, to send fax tones such as CED on the traffic channel. After the MS where the called user is located detects fax tones such as CED, it notifies the called party BSC to initiate a service request, and the side where the called party BSC and MGC are connected triggers a handover process, and triggers the process of service negotiation on the side of the air interface. The interface and the air interface establish a connection to the IWF. At this time, the MGC notifies the IWF to establish the called mode. At this time, the MGC can switch the bearer until reaching the calling user, and then, the calling side MGC notifies the calling party BSC to initiate the service switching to fax. The follow-up process is the same as the process before port A becomes IP. In this way, both the calling and called users establish connections to the IWF, start to perform fax services, and realize voice-to-fax service switching.

Fig. 7 is a flowchart showing another service switching method according to the present invention, the method includes the following steps: Step S702, during the voice call, when the called party mobile station receives the service switching signal of the called user equipment Tone, carry out service negotiation and hard handover through the base station controller of the called party, and establish the connection between the called party and the network interworking function unit of the called party; step S704, the mobile switching center of the calling party and the mobile switching center of the called party carry out the bearer Handover, when the handover is completed and the network interworking function unit of the called party is activated, the base station controller inserts codec resources to detect the fax tone signal on the IP side; and step S706, when the base station controller detects the fax tone signal on the IP side, the main The calling party's base station controller initiates service switching, establishes a connection between the calling party and the calling party's network interworking function unit, and completes the service switching.

Fig. 8 is a block diagram showing another service switching system according to the present invention, the system includes: a called party connection establishment device 810, located at the called party side, used for calling the mobile station of the called party during a voice call When receiving the service switching signal tone of the called user equipment, perform service negotiation and hard switching through the base station controller of the called party, and establish a connection between the called party and the network interworking function unit of the called party; the IP side fax tone signal detection device 820 , used to enable the calling party and the called party mobile switching center to perform bearer switching. After the switching is completed and the network interworking function unit of the called party is activated, the base station controller inserts codec resources to detect the fax tone signal on the IP side; and the calling party Party connection establishment device 830, located on the calling party side, is used for when the base station controller detects the fax tone signal on the IP side, the calling party base station controller initiates service switching, and establishes the calling party and the calling party network interworking functional unit The connection between them completes the service switching.

It can be seen from the above that the present invention realizes the switching function of the voice service to the IWF service of the fax service in the case of IP-based A port under the CDMA mobile communication environment, and does not change the user's usage habits, which greatly facilitates the user's operation . And the process compatibility is very good. Fax signals are transmitted in-band, the fax is switched in time, and the success rate is improved.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (16)

1. A service switching method, characterized in that, comprising: Step S102, during the voice call, when the called party mobile station receives the service switching signal tone of the called user equipment, it performs service negotiation and hard handover through the called party base station controller, and establishes the called party and called party the connection of the calling party's Interworking Functional Unit; and Step S106, the base station controller of the calling party starts service switching by receiving the in-band message, establishes a connection between the calling party and the network interworking functional unit of the calling party, and completes the service switching; In the case that both the calling party and the called party have respectively established connections to the calling party/called party network interworking function unit, When the calling party and the called party are in the same end office, the media gateway controller of the called party and/or the calling party according to the base station controller of the called party and/or the calling party or The service request message received by the media gateway of the called party and/or the calling party determines the fax direction; and When the calling party and the called party are in different end offices, the media gateway controller of the called party and/or the calling party The request message identifies the sender of the fax. 2. The service switching method according to claim 1, characterized in that, between the step S102 and the step S106, comprising: In step S104, the called MSC initiates a bearer switching request to the calling MSC, and the calling MSC performs the bearer switching. 3. The service switching method according to claim 1, characterized in that the step S106 includes the following steps, The base station controller of the calling party judges the calling and called direction of the fax by receiving the in-band message, and sends a handover request message to the mobile switching center of the calling party; The called party's mobile switching center initiates a bearer switching request to the calling party's mobile switching center, and the calling party's mobile switching center performs the bearer switching; and After receiving the response from the calling party's mobile switching center, the calling party's base station controller starts to perform service switching, establishes a connection between the calling party and the calling party's network interworking function unit, and completes the service switching. 4. The service switching method according to claim 2, characterized in that the step S102 further comprises the following steps, Before the network interworking function unit of the called party is activated, the base station controller of the called party packs the CED fax tone message sent by the mobile station of the called party into a message, and sends it to the mobile switching center of the called party through the media layer; or After the network interworking function unit of the called party is activated, the media gateway converts the fax tone sent by the network interworking function unit of the called party into a message and sends it to the base station controller of the calling party. 5. The service switching method according to claim 4, wherein the message is at least one of 2833/ced, 2833/v21flag, and 2833/cng. 6. The service switching method according to claim 4, characterized in that, in the step S104, by describing the corresponding bearer information required by the fax in the bearer switching, it is indicated to switch to a bearer type suitable for the fax service, wherein Include at least the following description methods: Extend the attribute description in the description of the session description protocol, adopt the description in the V152 protocol, and add a private description in the description of the extended session description protocol. 7. The service switching method according to claim 6, characterized in that the step S106 comprises the following steps: Step S1062, after receiving the bearer switching request, the calling party's mobile switching center switches the bearer; Step S1064, the base station controller of the calling party judges the calling and called direction of the fax by receiving the in-band message, and sends a switching request message to the mobile switching center of the calling party; and Step S1066, after the base station controller of the calling party receives the response from the mobile switching center of the calling party, it starts to switch services, establishes a connection between the calling party and the network interworking function unit of the calling party, and completes Business switching. 8. A service switching system, characterized in that it comprises, The called party connection establishment device is located at the called party side, and is used for, during the voice call, when the called party mobile station receives the service switching signal tone of the called user equipment, through the called party's base station controller Carry out service negotiation and hard handover, and establish a connection between the called party and the network interworking functional unit of the called party; and The calling party connection establishment device is located on the calling party side, and is used to enable the calling party's base station controller to start service switching by receiving an in-band message, and establish a connection between the calling party and the calling party's network interworking functional unit connection to complete service switching; In the case that both the calling party and/or the called party have established a connection to the calling party/called party network interworking function unit, When the calling party and the called party are in the same end office, the media gateway controller of the called party and/or the calling party The service request message received by the party and/or the media gateway of the calling party determines the fax direction; and When the calling party and the called party are in different end offices, the media gateway controller of the called party and/or the calling party The request message identifies the sender of the fax. 9. The service switching system according to claim 8, characterized in that it comprises: The bearer switching request initiating device is located between the calling party and the called party, and is used to make the mobile switching center of the called party initiate a bearer switching request to the mobile switching center of the calling party, and the mobile switching center of the calling party performs the bearer switching. 10. The service switching system according to claim 8, characterized in that, the calling party connection establishment device includes: The calling party service trigger module is used to enable the calling party base station controller to judge the calling and called direction of the fax by receiving the in-band message, and send a service switching request to the calling party mobile switching center; The calling party bearer switching request initiation module is used to make the called party mobile switching center initiate a bearer switching request to the calling party mobile switching center after the calling party base station controller triggers the service switching process, and the calling party mobile switching center performs bearer switching; and The calling party service switching module is used to start service switching after the calling party base station controller receives the response from the calling party mobile switching center, and establish the calling party and the calling party network The connection of the intercommunication functional units completes the service switching. 11. The service switching system according to claim 9, wherein the called party connection establishment device further comprises: The base station controller message sending module is used to make the base station controller of the called party type the CED fax tone message sent by the mobile station into a message and send it to the called party through the media layer before the network interworking function unit of the called party is activated a mobile switching center; or The media gateway message sending module is used to make the media gateway send the fax tone sent by the network interworking function unit of the called party into a message and send it to the base station controller of the calling party after the network interworking function unit of the called party is activated. 12. The service switching system according to claim 11, wherein the calling party base station controller receives at least one of the following messages: 2833/ced, 2833/v21flag, 2833/cng. 13. The service switching system according to claim 11, characterized in that, The calling party bearer switch request initiation device indicates to switch to the bearer type suitable for the fax service by describing the corresponding bearer information required by the fax in the bearer switch, which at least includes the following description methods: Extend the attribute description in the description of the session description protocol, adopt the description in the V152 protocol, and add a private description in the description of the extended session description protocol. 14. The service switching system according to claim 13, wherein the calling party connection establishment device comprises: The calling party bearer switching request module is used to switch the bearer after the calling party mobile switching center receives the bearer switching request; The calling party service triggering module is used to enable the calling party base station controller to judge the calling and called direction of the fax by receiving the in-band message, and send a service switching request to the calling party mobile switching center; and The calling party service switching module is used to start service switching after the calling party base station controller receives the response from the calling party mobile switching center, and establish the calling party and the calling party network The connection of the intercommunication functional units completes the service switching. 15. A service switching method, comprising: Step S702, during the voice call, when the called party mobile station receives the service switching signal tone of the called user equipment, it performs service negotiation and hard handover through the called party base station controller, and establishes the called party and called party The connection of the calling party's network interworking functional unit; Step S704, the mobile switching center of the calling party and the mobile switching center of the called party perform bearer switching. After the switching is completed and the network interworking function unit of the called party is activated, the base station controller of the called party inserts codec resources to detect the fax tone on the IP side Signal; as well as Step S706, when the base station controller of the calling party detects the fax tone signal on the IP side, the base station controller of the calling party initiates service switching, and establishes a connection between the calling party and the network interworking functional unit of the calling party to complete the service switching. 16. A service switching system, comprising: The called party connection establishment device is located on the called party side, and is used for performing service negotiation through the called party base station controller when the called party mobile station receives the service switching signal tone of the called user equipment during the voice call and hard handover, establishing a connection between the called party and the called party network interworking functional unit; The fax tone signal detection device on the IP side is used for bearer switching between the calling party and the called party mobile switching center. Fax tone signals on the side; and The calling party connection establishment device is located on the calling party side, and is used for when the calling party's base station controller detects the fax tone signal on the IP side, the calling party's base station controller initiates service switching, and establishes the calling party and the The connection between the network interworking functional units of the calling party is described, and the service switching is completed.

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