WO2012058932A1

WO2012058932A1 - Method and system for late forward processing

Info

Publication number: WO2012058932A1
Application number: PCT/CN2011/076136
Authority: WO
Inventors: 张红霞; 张强; 丁兆明
Original assignee: 中兴通讯股份有限公司
Priority date: 2010-11-03
Filing date: 2011-06-22
Publication date: 2012-05-10
Also published as: CN102469424B; CN102469424A

Abstract

The present invention discloses a method and a system for late forward processing. The method comprises that when a calling subscriber originates a call to a called subscriber, a gateway mobile switching center (GMSC) originates a route for the first time to the home location register (HLR) of the called subscriber (S402); when the called subscriber can not reply, the GMSC obtains the failure reason why the called subscriber can not reply, and originates a route for a second time to the HLR of the called subscriber according to the failure reason (S404); and the GMSC receives the forward information returned by the HLR of the called subscriber, and continues connecting the call originated by the calling subscriber to a forward subscriber designated in the forward information according to the forward information (S406). The session resources can be saved by employing the present invention.

Description

TECHNICAL FIELD The present invention relates to the field of communications, and in particular to a late forwarding processing method and system. BACKGROUND OF THE INVENTION With the rapid increase of communication services, inter-office round-tripping may occur in the following cases (assuming that the calling user is an A user, the called user is a B user, and the forwarding user is a C user): A user calls B user The B user has a late turn. When the B user's visited VMSC (Visit Mobile Switching Center) is different from the C user's visited VMSC, a voice path will occur. The forward forwarding refers to the forwarding service that occurs after the VMSC of the B user receives the IAM (Initial Address Message) message. The specific subdivision situation is more than 4, and the scene is as follows (not limited to the following scenarios):

1) The B user and the C user have the same attribution, the B user has roamed, the A user calls the B user, and the B user transfers to the C user later;

2) The B user and the C user belong to the same MSC (Mobile Switching Center), the C user roams, the B user does not roam, the A user calls the B user, and the B user transfers to the C user later;

3) The B user and the C user belong to the same MSC, and the B user and the C user roam and the VMSCs of the two visits are different. The A user calls the B user, and the B user transfers to the C user later;

4) The B user and the C user belong to the MSC. The B user and the C user do not roam. The A user calls the B user, and the B user transfers to the C user later.

5) The B user and the C user belong to the MSC. The B user and the C user roam and the VMSCs of the two are different. The A user calls the B user, and the B user transfers to the C user later.

6) The B user and the C user belong to the MSC. One of the B users and the C user roams and the VMSCs of the two are different. The A user calls the B user, and the B user transfers to the C user later. The application scenario of 6) is taken as an example for description. FIG. 1 is a schematic diagram of the path routing of the existing home subscriber calling the called subscriber, and the call forwarding is forwarded to the home subscriber, including the following steps: Step S102: The calling user calls the local called user, and the called user roams to another country or region, and the routing end office of the calling party is connected to the local originating caller/the forwarded user's provincial gateway. Step 4: S, the call is connected to the home international gateway; Step S106, the call is connected to the international gateway of the called roaming; Step S108, the call is connected to the long distance of the roaming user of the called roaming; Step S110 The call is connected to the end office where the called roaming roaming user is located; Step S112, the called user has a late forwarding, and the user is forwarded to the home location, and the call routing roaming roaming user's end office is connected to the called roaming end. The remote roaming station where the user roams; the step 4 gathers S 114, the call is connected to the long-distance bureau where the roaming user of the called roaming station is connected to the international gateway office of the called roaming place; step S 116, the call is connected to the international gateway office of the attribution; step S 118 The call is connected to the provincial exchange where the user is forwarded; step S120, the call is connected to the end office where the user is forwarded. It can be seen that a voice path is formed between step S102 and step S120 in the session. A route optimization method is mentioned in the related art. As shown in FIG. 2, for convenience of illustration, in FIG. 2, the GMSC (Gateway Mobile Switching Center) of the visited network where the calling user is located is represented by GMSC. The HLR (Home Location Register) of the called user is represented as HLRB, the VLR of the called user's roaming place is represented as VLRB, the VMSC of the called user is represented as VMSCB, and the VMSC of the forwarded user is represented as VMSCC. The method includes: Step S202: The calling user calls the local called user, and the called user roams to other countries, and the GMSC sends a routing request message to the HLRB, where the preferred routing related information is carried; Step S204, the HLRB sends the PRN to the VLRB (Providing Roaming) Number, providing a roaming number request) message, carrying preferred routing related information; Step S206, the VLRB returns a PRN ACK (Provide Roaming Number Acknowledge) message to the HLRB, which carries the preferred routing related information; Step S208, the HLRB returns a routing request confirmation message to the GMSC, where the preferred routing related information is carried; Step S210: The GMSC sends an IAM message to the VMSCB. Step S212: The VMSCB sends an incoming call request message to its corresponding VLRB. Step S214: The VLRB sends an incoming call confirmation message to its corresponding VMSCB. Step S216: The VMSCB obtains the forward forwarding information according to the obtained information. Sending a continuation call processing message to the GMSC, instructing the GMSC to perform a preferred routing process; Step S218, the GMSC sends a routing request message requesting forwarding information to the HLRB after receiving the preferred routing processing message; Step S220, the HLRB sends a routing request confirmation message to the GMSC; S222. The GMSC determines that the calling user and the forwarding user are in the same country, and sends a continuation call processing confirmation message to the VMSCB where the original called user is roaming. Step S224: The GMSC sends a release message to the VMSCB where the original called user roams; Step S226, GMSC Find the way based on the number you are forwarding Forward transfer user's VMSCC send the IAM. FIG. 3 is a schematic diagram of the voice route of the route optimization method shown in FIG. 2, including the following steps: Step S302: The local route of the call originating user of the call originating to the home caller/going forward user Step S304: The call is forwarded to the end office where the user is located. It can be seen from the above description that the preferred routing function provided by the related art can save the voice path, but the function needs to be supported in both the visited place and the attribution place. In actual operation, the visited place cannot be guaranteed to support the preferred routing function, that is, The applicability of the related art to the route optimization method for the forward call is not high. In practical applications, the problem of session detour in the session cannot be avoided, resulting in waste of session resources. In view of the inability of the related art to avoid the occurrence of session detours in the session and the waste of session resources, an effective solution has not been proposed yet. SUMMARY OF THE INVENTION A primary object of the present invention is to provide a method and system for processing a late forwarding process to at least solve the above problem of avoiding the occurrence of session detour in a session and causing waste of session resources. According to an aspect of the present invention, a late forwarding processing method is provided, including: when a calling user initiates a call to a called user, a gateway mobile switching center (GMSC) sends a home location register to the called user ( HLR) initiates a first route; when the called user is unable to answer, the GMSC acquires a failure reason that the called user cannot answer, and initiates the HLR to the called user according to the failure reason a second routing; the GMSC receives the forwarding information returned by the HLR of the called user, and connects the call initiated by the calling user to the forwarding specified in the forwarding information according to the forwarding information user. Preferably, the failure reason that the called user cannot answer includes one of the following: the called user is inaccessible, the called user is busy, and the called user has no response. Preferably, when the called user is unable to answer, the GMSC obtains the failure reason that the called user cannot answer from the release message, and initiates the first request to the HLR of the called user according to the failure reason. The secondary method, the method further includes: when the called mobile switching center (VMSC) of the called user finds that the called user cannot answer, the VMSC of the called user sends the release message to the GMSC, indicating If the call fails, the release message carries the cause of the failure; the GMSC sends a route request message to the HLR of the called user according to the failure reason, and the route request message carries the failure reason. Preferably, the release message includes: a ringing message or a call progress message. Preferably, when the called user is inaccessible, the called user is busy, or the called user does not answer, the VMSC of the called user sends the release message to the GMSC. Preferably, when the called user is not timely, the inserted user data request message sent by the VLR of the called user does not carry forwarding data, where the forwarding data includes a forwarding number. Preferably, the reason why the GMSC obtains the failure of the called user to be unsuccessful comprises: the GMSC obtaining, from the release message, a reason for the failure of the called user to be unresponsive. Preferably, before the GMSC obtains the failure reason that the called user cannot answer, the method further includes: the calling user calling the called user, and the GMSC sending a routing request to the HLR of the called user. a message: the HLR of the called user sends a Roaming Number Request (PRN) message to the VLR of the called user; the VLR of the called user sends a roaming number confirmation (PRN ACK) to the HLR of the called user. a message; the HLR of the called user sends a route request confirmation message to the GMSC; the GMSC sends an initialization address message to the VMSC of the called user. Preferably, after the GMSC initiates the first routing to the HLR of the called user, and before the second routing is initiated to the HLR of the called user according to the failure reason, the method further includes: the HLR of the called user is The first route confirmation message carries the forward query flag. According to another aspect of the present invention, a late forwarding processing system is provided, including a gateway mobile switching center (GMSC) and a home location register (HLR) of a called user: the GMSC is set as a calling party pair When the called user initiates a call, initiates a first route to the HLR of the called user; when the called user cannot answer, obtains a failure reason that the called user cannot answer, and according to the failure The reason is that a second route is initiated to the HLR of the called user; receiving forwarding information returned by the HLR of the called user, and connecting the call initiated by the calling user to the forwarding information according to the forwarding information The forwarded user specified in the call; the HLR of the called user is set to send the forwarding information to the GMSC during the second routing. Preferably, the system further includes a visited mobile switching center (VMSC) of the called user: the VMSC of the called user is configured to send a release message to the GMSC when the called user cannot find the response, indicating If the call fails, the release message carries the cause of the failure; the GMSC is further configured to send a route request message to the HLR of the called user according to the failure reason, where the route request message carries the failure reason. Preferably, the GMSC is further configured to: when the called user cannot answer, obtain a failure reason that the called user cannot answer from the release message. Preferably, the release message includes: a ringing message or a call progress message. Preferably, the GMSC is further configured to: when the calling user calls the called user, send a routing request message to the HLR of the called user; send an initialization address message to the VMSC of the called user; The HLR of the called user is further configured to send a roaming number request PRN message to the VLR of the called user; send a routing request confirmation message to the GMSC; Also included is a visited location register (VLR) of the called user, the VLR of the called user being configured to send a roaming number confirmation PRN ACK message to the HLR of the called user. In the embodiment of the present invention, the switch of the called user is not required to perform any special processing, so that the session is directly connected between the calling user and the forwarded user, and does not need to be bypassed by the VMSC of the called user. Can save the channel resources. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are set to illustrate,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, In the drawings: FIG. 1 is a schematic diagram of a call route in which a calling party calls a local called user according to the related art, and the called user has a late turn forward and forwards to a forward user, wherein the forward user and the forward call user Figure 2 is a flowchart of a route optimization method for the application scenario of Figure 1 according to the related art; Figure 3 is a schematic diagram of the voice route of the route optimization method for the application scenario of Figure 1 according to the related art. 4 is a process flow diagram of a method for optimizing a forward forwarding route according to an embodiment of the present invention; FIG. 5 is a flowchart of a second routing initiated by a GMSC according to an embodiment of the present invention; A flowchart of a process for a called user to obtain an updated roaming address according to an embodiment of the present invention; FIG. 7 is a diagram of a user belonging to a HLR not visiting a user when roaming to a visited network that does not support the call forwarding route optimization function according to an embodiment of the present invention; FIG. 8 is a flowchart of a process before a GMSC acquires a failure reason that a called user cannot respond, according to an embodiment of the present invention; FIG. FIG. 10 is a flow chart showing a location update process of a late turn processing method according to an embodiment of the present invention; FIG. 11 is a schematic diagram of a location update process according to an embodiment of the present invention; A first structural schematic diagram of a late turn processing system of an embodiment; Fig. 12 is a second schematic structural view of a late turn processing system according to an embodiment of the present invention; Fig. 13 is a third structural diagram of a late turn processing system according to an embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict. It is mentioned in the prior art that there is a problem that the call path is not avoided in the session, and the session resources are wasted. In order to solve the above technical problem, the embodiment of the present invention provides a late forwarding processing method, which is shown in FIG. The method includes: Step S402: When the calling user initiates a call to the called user, the gateway mobile switching center GMSC initiates a first routing to the called user's home location register HLR; Step S404, when the called user cannot answer, the GMSC obtains The reason why the called user cannot answer the failure, and initiates the second routing request forwarding information to the HLR of the called user according to the failure reason; wherein, the GMSC can obtain the failure reason from the release message sent by the VMSC of the called user to the GMSC. Step S406: The GMSC receives the forwarding information returned by the HLR of the called user, including information such as the forwarding number, and connects the call initiated by the calling user to the forwarding user specified in the forwarding information according to the forwarding information. Preferably, the precondition for step S404 is that the HLR carries the forward query flag in the first routing confirmation message. In the embodiment of the present invention, even if the switch of the called user roaming does not support the route optimization function of the related technology, the embodiment of the present invention can make the session directly connected between the calling user and the forward user without going through the Calling the user's visited place VMSC back, can save the channel resources. When implemented, the embodiment of the present invention is applicable not only to mobile call mobile users, but also to fixed users calling mobile users, and the forwarded users may be mobile users or fixed users. In the implementation, the reasons for the failure of the called user to answer include a variety of situations, such as the inability to page the called user, the called user is inaccessible, the called user is busy, the called user has no response, etc., depending on the actual situation. Happening. In the implementation, when the called user is unable to answer, the GMSC obtains the failure reason that the called user cannot answer, and initiates a second routing to the HLR of the called user according to the failure reason. The processing flow is as shown in FIG. 5, including: Step S502: When the called user's visited mobile switching center VMSC finds that the called user cannot answer, the VMSC of the called user sends a release message to the GMSC, indicating that the call fails, and the release message carries the reason for the failure; Step S504, the GMSC according to the failure reason The HLR of the called user sends a route request message, and the route request message carries the reason for the failure. In implementation, the release message may have various implementation means. For example, the ringing message or the call progress message may be used as the release message, and of course other messages may be used, and is not limited to the ringing message or the call progress message. In the implementation, when the called user is not timely, the inserted user data request message sent by the VLR of the called user does not carry the forwarding data, wherein the forwarding data includes the forwarding number. As shown in FIG. 6, the process for the called user to obtain the updated visited address includes: Step S602: The visited location register VLR of the called user sends a location update message to the HLR of the called user; Step S604, the HLR of the called user Sending a user data request message to the VLR of the called user, where the inserted user data request message does not carry the forwarding information; Step 4 S606, the VLR of the called user returns an insert user data confirmation message to the HLR of the called user; Step S608, the HLR of the called user returns a location update confirmation message to the VLR of the called user's roaming place. Considering the compatibility with related technology call forwarding and call forwarding route optimization, when the called user's visited network does not support call forwarding route optimization, in order to avoid the call forwarding directly in the visited network, instead of directly returning to release The following further solutions are provided in the embodiment of the present invention: Solution 1: When a user roams to a visited network that does not support the call forwarding route optimization function, the user home HLR does not insert the forwarding information into the user visited network, and the processing flow is as shown in the figure. As shown in 7, including: Step S702, the user's visit location register VLR sends a location update message to the user's HLR. Step S704, the user's HLR sends a first insert user data request message to the user's visited network VLR, where the first insert user data request message is not Carrying the forwarding information; Step S706, the VLR of the user returns an insertion user data confirmation message to the HLR of the user, where the message carries an indication that the visited network supports the call routing optimization function; Step S708: The user's HLR checks whether the user visited the network supports call routing. The optimization function, if not supported, the HLR does not insert the user forwarding information into the user visited network in the subsequent insertion user data request message. After the download user data is completed, the HLR returns a location update confirmation message to the VLR of the user's roaming place. In the implementation, the GMSC obtains the failure reason that the called user cannot answer, and performs the operation shown in FIG. 8 differently from the route optimization method mentioned in the related art: Step S802, the calling user calls the called user, and the GMSC calls the called party. The HLR of the user sends a routing request message, where the message carries the indication information of whether the GMSC supports enhanced route optimization. Step S804: The HLR of the called user sends a roaming number request PRN message to the VLR of the called user to visit the location; Step S806, The VLR of the calling user sends a roaming number confirmation PRN ACK message to the HLR of the called user. Step S808: The HLR of the called user checks whether the GMSC supports the enhanced route optimization function provided by the present invention by using the indication information in the routing request message, if the GMSC If not, the HLR inserts the forwarding information into the visited network of the called user, including the forwarding forwarding data of the user such as the forwarding number; Step S810, the HLR of the called user sends a routing request confirmation message to the GMSC; Step S812, the GMSC calls to the called party. The user's VMSC sends an initialization address message. Preferably, after step S804, before step S806, if the VLR sends a restore user data request (Restore) to the HLR, the method for the HLR to insert user data into the VLR in the Restore process is the same as the method of inserting user data in FIG. Solution 2: Regardless of whether the visited network that the user roams supports the route optimization function of the related technology, the HLR does not insert the user forwarding information into the user visited network. The difference between the subsequent call processing and the first one is that if the GMSC supports the enhanced route optimization function provided by the embodiment of the present invention, the HLR needs to further check whether the user visited the network supports the prior art route optimization function, and if the user visits the network to support the existing technology route, For the optimization function, the HLR needs to insert the user forwarding information into the user visited network to ensure that the route optimization function of the related technology takes precedence. Preferably, the user visited the network to carry an indication of whether the route optimization function is supported in the PRN ACK response message, and the HLR determines, according to the indication information, whether the user visited the network supports the route optimization function of the related technology. Preferably, if the VLR sends a restore user data request (Restore) to the HLR during the call, the HLR does not insert the user forward to the user visited network during the Restore process, regardless of whether the visited network of the roaming user supports the route optimization function of the related technology. information. Solution 3: The user home HLR inserts the user forward data information into the visited network that normally roams to the user when processing the location update process. In the subsequent call processing, the called user belongs to the HLR after the PRN ACK response message, and determines whether the GMSC supports the enhanced route optimization function of the present invention and whether the visited network in which the user roams supports the route optimization function of the related technology. If the GMSC supports the enhanced route optimization function of the present invention, and whether the visited network that the user roams does not support the route optimization function of the prior art, the HLR deletes the user data message to the visited network where the user roams, and deletes the user saved in the user visited network VLR. Forward data information. Preferably, the user visited the network to carry an indication of whether the route optimization function is supported in the PRN ACK response message, and the HLR determines, according to the indication information, whether the user visited the network supports the route optimization function of the related technology. In order to facilitate comparison with the route optimization method provided by the related art, the method for processing the night turnaround provided by the embodiment of the present invention is represented by a flowchart similar to that of FIG. 2, see FIG. 9: Step S902, Calling by the calling party The local called user, the called user roams to other countries, and the GMSC of the visited user of the calling user sends a routing request message to the HLR of the called user. Step S904: The HLR of the called user sends the VLR of the called user to the VLR of the called user. a PRN message; Step S906, the VLR of the called user's visited place sends a PRN ACK message to the HLR of the called user; Step S908, the HLR of the called user sends a route request confirmation message to the GMSC of the called user's home location; Step S910, the GMSC of the called user's home location sends an initialization address message to the called user's visited VMSC; Step S912, the called user The visited VMSC finds that the called user is busy or the paging is unresponsive or has no response; Step S914, the called user VMSC sends a release message (ringing message or call progress message) to the GMSC of the home location, indicating that the call fails; S916, the GMSC of the called user's home location sends a routing request message to the HLR of the called user according to the reason for the release (ie, the reason for the failure) (the reason for carrying the failure); Step S918, the HLR of the called user according to the routing request The reason for the failure of the GMSC in the message is to return the corresponding forwarding information to the GMSC to be routed. Step S920: The GMSC connects the call to the user indicated in the forwarding information according to the forwarding information in the HLR routing response message. In the implementation, the method for processing the forward forwarding according to the embodiment of the present invention is different from the processing method mentioned in the related art, and correspondingly, the charging criteria are not completely the same. The interaction processing with the charging criteria in the existing route optimization technology is described. When the GMSC determines that the current routing status meets the charging criteria in the existing route optimization technology, the process proceeds to step S920, and the current routing condition does not satisfy the existing route. It is up to the operator to decide whether to perform step S920 or release the call when optimizing the charging criteria in the technology. FIG. 10 is a schematic diagram of a location update process using the late forwarding processing method provided by the first or second aspect of the embodiment of the present invention, including the following steps: Step S 1002: A VLR of a user visited location sends a location update request message to a user's HLR. Step S1004: The user's HLR sends the insert user data request message to the visited VLR without carrying forward information; Step S1006: The visited VLR returns an insert user data confirmation message to the user's HLR; Step S1008, the user The HLR returns a location update confirmation message to the VLR of the roaming place. Based on the same inventive concept, the embodiment of the present invention further provides a late forwarding processing system, including a gateway mobile switching center GMSC 1101 and a home location register HLR 1102 of the called user. For the structure, please refer to FIG. 11 :

GMSC 1101, when the calling user initiates a call to the called user, initiates a first routing to the called user's HLR 1102; when the called user cannot answer, obtains the failed reason that the called user cannot answer, and then 艮According to the reason for failure, a second route is initiated to the HLR 1102 of the called user; the forwarding information returned by the HLR 1102 of the called user is received, and the call initiated by the calling user is connected to the forwarding information according to the forwarding information. Forwarding user; The called user's HLR 1102, is set to send forwarding information to the GMSC 1101 during the second routing. In an embodiment, referring to FIG. 12, the forward-to-forward processing system further includes a visited mobile switching center VMSC 1201 of the called user: the VMSC 1201 of the called user is set to send to the GMSC 1101 when the called user cannot be answered. The release message indicates that the call fails, and the release message carries the release reason. The GMSC 1101 is further configured to send a route request message to the HLR 1002 of the called user according to the release reason, and the route request message carries the release reason. In one embodiment, the called user's HLR 1102 is further configured to: obtain the visited address of the called user after updating. In one embodiment, referring to FIG. 13, the forward-forward processing system further includes a visited location register VLR 1301 of the called user: the VLR 1301 of the called user, configured to send a location update message to the HLR 1102 of the called user; Receiving the inserted user data request message sent by the called user's HLR 1102, returning the inserted user data confirmation message to the called user's HLR 1102; the called user's HLR 1102 is also set to send the insertion to the called user's VLR 1301. a user data request message, where the inserted user data request message does not carry forwarding information; after receiving the inserted user data confirmation message, the location update confirmation message is returned to the VLR 1301 of the called user. In an embodiment, the GMSC is further configured to send a routing request message to the HLR 1102 of the called user when the calling user calls the called user; send an initialization address message to the VMSC 1301 where the called user is roaming; The HLR 1102 is further configured to send a roaming number request PRN message to the VLR 1201 where the called user is roaming; send a routing request confirmation message to the GMSC 1101; the called user's VLR 1301 is also set to the called user's HLR 1102. Send a roaming number to confirm the PRN ACK message. From the above description, it can be seen that the present invention achieves the following technical effects: In the embodiment of the present invention, the switch of the called user is not required to perform any special processing, so that the session is forwarded to the calling user and forwarded. The direct connection between users does not need to go through the VMSC of the called user's visited place, which can save the channel resources. Obviously, those skilled in the art should understand that the above modules or steps of the present invention can be implemented by a general-purpose computing device, which can be concentrated on a single computing device or distributed over a network composed of multiple computing devices. Alternatively, they may be implemented by program code executable by the computing device, such that they may be stored in the storage device by the computing device and, in some cases, may be different from the order herein. The steps shown or described are performed, or they are separately fabricated into individual integrated circuit modules, or a plurality of modules or steps are fabricated as a single integrated circuit module. Thus, the invention is not limited to any specific combination of hardware and software. The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the scope of the present invention are intended to be included within the scope of the present invention.

Claims

Claim

1. A late forwarding process, comprising:

When the calling user initiates a call to the called user, the gateway mobile switching center GMSC initiates a first routing to the called subscriber's home location register HLR;

When the called user is unable to answer, the GMSC acquires the failure reason that the called user cannot answer, and initiates a second routing to the HLR of the called user according to the failure reason;

The GMSC receives the forwarding information returned by the HLR of the called user, and connects the call initiated by the calling user to the forwarded user specified in the forwarding information according to the forwarding information.

2. The method according to claim 1, wherein the failure reason that the called user cannot answer includes one of the following: the called user is inaccessible, the called user is busy, and the called user does not answer. .

3. The method according to claim 1, wherein, when the called user is unable to answer, the GMSC acquires a failure reason that the called user cannot answer, and then according to the failure reason to the The user's HLR initiates a second route, including:

When the called mobile switching center VMSC of the called user finds that the called user cannot answer, the VMSC of the called user sends a release message to the GMSC, indicating that the call fails, where the release message carries the Reason for failure;

The GMSC sends a routing request message to the HLR of the called user according to the failure reason, where the routing request message carries the failure reason.

The method according to claim 1, wherein, when the called user is inaccessible, the called user is busy, or the called user does not answer, the VMSC of the called user sends a release to the GMSC. Message.

The method according to claim 1, wherein, when the called user is not timely, the inserted user data request message sent by the VLR of the called user does not carry forward data, wherein the forward data Includes forward number.

The method according to claim 1, wherein the failure of the GMSC to obtain the failed response of the called user includes:

The GMSC obtains the failure reason that the called user cannot answer from the release message.

7. The method of any of claims 3, 4, and 6, wherein the release message comprises: a ringing message or a call progress message.

The method according to any one of claims 1 to 6, wherein, before the GMSC acquires a failure cause that the called user cannot answer, the method further includes:

The calling user calls the called user, and the GMSC sends a routing request message to the HLR of the called user;

The HLR of the called user sends a roaming number request PRN message to the VLR of the called user;

The VLR of the called user sends a roaming number verification PRN ACK message to the HLR of the called user;

The HLR of the called user sends a routing request confirmation message to the GMSC; the GMSC sends an initialization address message to the VMSC of the called user.

The method according to any one of claims 1 to 6, wherein, after the GMSC initiates a first route to the HLR of the called user, the GMSC initiates the HLR according to the failure reason to the called user. Before the second routing, the method further includes: the HLR of the called user carries a forwarding query flag in the first routing confirmation message.

10. A late-forward processing system, including the gateway mobile switching center GMSC and the called subscriber's home location register HLR:

The GMSC, when the calling user initiates a call to the called user, initiates a first routing to the HLR of the called user; when the called user cannot answer, obtaining the called user cannot Responding to the reason for the failure, and initiating a second route to the HLR of the called user according to the failure reason; receiving the forwarding information returned by the HLR of the called user, and referring to the forwarding information And connecting the call initiated by the calling user to a forward user specified in the forwarding information;

The HLR of the called user is set to send the forwarding information to the GMSC during the second routing.

11. The system according to claim 10, wherein

The system further includes: the visited mobile switching center VMSC of the called user, configured to send a release message to the GMSC, indicating that the call fails, where the called user fails to answer, wherein the release message carries The reason for the failure;

The GMSC is further configured to send a routing request message to the HLR of the called user according to the failure reason, where the routing request message carries the failure reason.

12. The system according to claim 10, wherein

The GMSC is further configured to: when the called user cannot answer, obtain a failure reason that the called user cannot answer from the release message.

The method according to claim 10 or 11, wherein the release message comprises: a ringing message or a call progress message.

The system according to any one of claims 10 to 12, wherein the system further comprises a visitor location register VLR of the called user,

The GMSC is further configured to: when the calling user calls the called user, send a routing request message to the HLR of the called user; and send an initialization address message to the VMSC of the called user;

The HLR of the called user is further configured to send a roaming number request PRN message to the VLR of the called user; and send a routing request confirmation message to the GMSC;

The VLR of the called user is set to send a roaming number confirmation PRN ACK message to the HLR of the called user.