WO2007041963A1

WO2007041963A1 - A method for establishing, optimizing bearer path and apparatus thereof

Info

Publication number: WO2007041963A1
Application number: PCT/CN2006/002688
Authority: WO
Inventors: Fang You; Wenyu Liu; Jie Xu; Yunfei Li
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2005-10-14
Filing date: 2006-10-12
Publication date: 2007-04-19

Abstract

A method for establishing, optimizing bearer path and apparatus thereof is provided, the method comprises: determine if the data coding formats of the bearer connection endpoints at both sides of the corresponding media gateway in the bearer path are identical, if the data coding formats of the bearer connection endpoints at both sides of the said media gateway are identical, then subtract the media gateway from the said bearer path, and update the bearer parameter at the bearer connection endpoint adjacent to the media gateway. Additionally, a respective bearer path management apparatus is also provided. The invention subtracts the respective media gateway from the said bearer path, and updates the bearer parameter at the bearer connection endpoint adjacent to the media gateway, or establishes a bearer path directly between the calling side access equipment and the called side access equipment, so as to optimize the bearer path, and releases the bearer resource of the media gateway after updating the bearer path, so that decreases the intermediate processing link of the media data stream, and therefore saves the bearer resource of the media gateway, thus improves the overall efficiency and performance of the network.

Description

Bearer path establishment, optimization method and device

Technical field

The present invention relates to the field of mobile communication technologies, and in particular, to a bearer path establishment and optimization method and apparatus under a bearer control separation architecture. Background technique

The mobile communication network is evolving to an all-IP network. At present, the architecture of the carrier and the control separation has been introduced in the circuit domain network. The original mobile switching center (MSC) is divided into a mobile softswitch (MSCe) and a media gateway (MGW, Media Gateway). Both devices are used for signaling control and bearer processing. In addition, after the A interface is IP, the Alp interface signaling between the base station (BS, Base Station) and the MSCe and the A2p interface data between the BS and the MGW are carried on the IP network, and the network location and interface connection of the relevant functional entity are Relationship, as shown in Figure 1, the MGW is also connected to the Public Switch Telephone Network (PSTN). According to the existing protocol, A2p not only provides a bearer path between the BS and the MGW, but also an IP bearer path between the base stations BS is provided by A2p.

After the voice bearer between the mobile switching center and the access device adopts IP, the routing TDM circuit bearer between the MGW and the access device is changed to an IP bearer. After the IP bearer is built, the access device and the MGW allocate their IP addresses and port numbers, and the MSCe exchanges the IP addresses and port numbers of the two entities and establishes a bearer. As shown in Figure 2, the routing TDM circuit bearer between the MGW and the BSC is changed to an IP bearer. Through the message interaction of the MSCe, the BSC and the MGW know the IP address, the port number, the codec of both parties, and complete the bearer establishment between the MGW and the BSC. After the bearer is established, if the codec capability of the calling side access device and the called side access device are different, the MGW performs codec conversion. If the MGW does not perform any conversion, the received media stream is directly transparently transmitted. However, when the codec capability of the calling side access device (which may also be referred to as a source access device) and the called side access device (which may also be referred to as a target access device) are the same, the MGW receives the media stream it receives. Direct pass-through will increase the intermediate processing of the media stream and occupy the resources of the MGW.

As shown in Figure 3, the IP bearer is used in the inter-office. The IP address of the two ends is negotiated through SIP signaling. The calling office notifies the MGW to establish an IP bearer through the ADD message. The MGW returns the allocation. IP endpoint information, the calling office carries the IP endpoint information of the local MGW in the INVITE message, and the supported CODEC list; the called office informs the MGW to establish an IP bearer through the ADD message (with the IP endpoint information allocated by the calling office MGW: The MGW returns the assigned IP endpoint information, the called office has the IP endpoint information of the local MGW in the 180 or 200 message, and the selected CODEC; the calling office MSCe notifies the local end of the IP endpoint information of the called office MGW through the MODIFY message. MGW, establishes an IP bearer.

Figure 4 takes a typical interoffice call flow as an example to describe the existing technical solution. For convenience, it is assumed that the A2p bearer parameters of the calling side BS are transmitted to the main in the Connection Management Service Request message. The called side MSCe, the A2p bearer parameter of the called side BS is transmitted to the called side MSCe in the Paging Response message, and the ring back tone is provided by the called party, and the home location register (HLR) is omitted in the message flow. The process of interacting with called routes. The specific call setup process is as follows:

1. The MSCel receives the CM Service Request message sent by the BS1, and carries the A2p bearer parameter, which mainly includes the expected encoding format list on the BS1 side, and the IP address and port number of the connection endpoint on the BS1;

2. The MSCel sends an ADD (add) message to the MGW1, requesting to allocate two RTP (Real Time Transport Protocol) type endpoints, corresponding to the bearer connection endpoints on the BS1 side and the called side respectively;

3. The MSCel receives the REPLY (Response) message returned by the MGW1, and carries the SDP (Session Descriptor Protocol) information of the two RTP endpoints, which respectively include the encoding format supported by the MGW1 and the IP address of each endpoint. And port number;

4. The MSCel sends an INVITE message to the MSCel, and carries the SDP corresponding to the RTP endpoint of the called side of the MGW1;

5. The MSCel sends an Assignment Request message to the BS1 to request the allocation of the air interface resource, and carries the A2p bearer parameter of the RTP endpoint corresponding to the BS1 side of the MGW1. 6. After the establishment of the air interface resource, the MSCel receives the Assignment sent by the BS1.

Complete (Assignment Completed) message;

7. After finding the location of the called party, MSCe2 sends a Paging Request message to BS2, which may carry a list of encoding formats obtained from the calling side;

8. MSCe2 receives the Paging Response message returned by BS2, which carries the BS2 side. The A2p parameter, including the encoding format accepted by the BS2 side, the IP address of the connection endpoint on the BS2, and the port number;

9. MSCe2 sends an ADD message to MGW2, requesting to allocate two RTP type endpoints, corresponding to the connection terminal of the BS2 side and the calling side respectively;

10. The MSCe2 receives the REPLY message returned by the MGW2, and carries the SDP information of the two RTP endpoints that are applied for, respectively, including the coding format supported by the MGW2, the IP address and port number of each endpoint;

11. The MSCe2 sends an Assignment Request message to the BS2 to request the allocation of the air interface resource, and carries the A2p bearer parameter of the RTP endpoint corresponding to the BS2 side of the MGW2;

12. After the establishment of the air interface resource, MSCe2 receives the Assignment sent by BS2.

Complete message;

13. The MSCel receives the 180 message returned by the MSCe2, and carries the SDP corresponding to the endpoint on the calling side of the MGW2.

14. MSCe2 sends a MODIFY (modify) message to MGW2, requesting to put back a ring tone to the RTP endpoint near the calling side;

15. The MSCe2 receives the REPLY message returned by the MGW2.

16. The MSCel sends a 180 PRACK (temporary response confirmation) message to the MSCe2;

17. The MSCel receives a 200 OK response of the PRACK message returned by the MSCe2.

18. The MSCel sends a MODIFY message to the MGW1, and updates the Remote (remote) SDP of the called side endpoint to the MGW2 brought in the 180 message near the calling side endpoint.

SDP;

19. MSCel receives the REPLY message returned by MGW1.

20. The one-way ring back tone data flow of the MGW2 to the calling user is established;

21, MSCe2 receives the Connect (Connect) message of BS2, indicating that the called user answers; 22. MSCe2 sends a MODIFY (Modify) message to MGW2, requesting to stop playing the ring back tone to the RTP endpoint near the calling side;

23. The MSCe2 receives the REPLY message returned by the MGW2.

24. The MSCel receives the 200 OK response of the INVITE message returned by the MSCe2.

25. MSCel sends a MODIFY message to MGW1, and the media stream of the called endpoint is sent. The attribute is modified to be bidirectional;

26. The MSCel receives the REPLY message returned by the MGW1.

27. MSCel returns an ACK (acknowledgement) message to MSCe2;

28. The establishment of the bidirectional bearer channel between the calling and called users is completed;

29. After the call ends, the called user hangs up, and MSCe2 receives the Clear Request sent by BS2.

(clear request) message;

30, MSCe2 sends a Clear Command message to BS2;

31. MSCel receives the BYE (disconnection) message sent by MSCe2;

32. MSCel sends a Clear Command message to BS1.

33. MSCel receives the Clear Complete message returned by BS1.

34, MSCel sends a BYE 200 OK response message to MSCe2;

35. The MSCel sends a SUBSTRACT message to the MGW1 to release the RTP endpoint occupied by the call.

36. The MSCel receives the REPLY message returned by the MGW1.

37. The MSCe2 receives the Clear Complete message returned by the BS2.

38. The MSCe2 sends a SUBSTRACT message to the MGW2 to release the RTP endpoint occupied by the call.

39. MSCe2 receives the REPLY message returned by MGW2.

In the network architecture in which the circuit domain network bears and controls the separation and the interface between the access network and the core network is IP, the MGW has the DTMF (Dual Tone Multi-Frequency) detection and insertion in the network. In addition to the media resource operation functions such as conference resources, another important function is to convert the codec format. It can be noted that within the IP-based circuit domain network, the function of the MGW for codec format conversion is gradually weakened, especially for the purpose of improving the voice quality and reducing the codec conversion process for the codec-free operation (TrFO, Transcoder). The support and application of Free Operation and Remote Transcoder Operation (RTO) accelerates this trend. As shown in FIG. 5, TrFO means that within the packet transmission network, if the same codec type is obtained by using out-of-band signaling negotiation, the voice codec is not required, and the compressed voice is directly transmitted from the end to the end. RTO means that only the same codec format can be obtained at both ends. One codec conversion. The agreement stipulates that after the TrFO and RTO have been tried successively, the encoding formats of the two ends cannot be matched. Only two codecs are used, and both formats are converted into a common transmission format (such as G.711) for interworking. In Figure 5, the EVRC (Enhanced Variable Rate Code) is an enhanced variable rate codec format, assuming that a codec (TC, TransCoder) exists on the MGW.

It can be seen from the above call flow that in the call process, even if the two ends of the call have negotiated the same coding format (the MGW is not required to provide the TC function), or the TC can be converted using the TC less than the number of MGWs. All MGWs are also always present in the bearer path, and the endpoints on the MGW cannot be released until the call is released.

Currently, the BS already supports the IP interface. However, in the prior art, even if the same coding format (TrFO) is used at both ends of the call within the packet transmission network, the bearer path in the call must pass through the MGW, which increases the delay of the data packet. This is not conducive to the improvement of voice quality. As more and more operators tend to use the unified coding format in the network, this shortcoming is becoming more and more obvious.

Most ordinary calls enter a stable (and possibly long-term) two-way conversation after the ringback tone is placed back to the caller. When both ends use the same coding format or the number of TCs is less than the number of MGWs passing through, the entire call is used. Carrying unnecessary MGWs during the call process will inevitably result in waste of resources (RTP endpoints) on the MGW.

When the calling party and the called party in the same encoding format are in the same BS, the bearer may be routed back through the MGW, and the IP transmission resource is wasted. Summary of the invention

The object of the present invention is to provide a bearer path establishment and optimization method and device to reduce route bypass and improve resource utilization.

A method for optimizing a bearer path according to the present invention includes:

The calling user calls the called user, and after establishing the bearer path of the current call, it is determined whether the data encoding format of the bearer connection endpoints on both sides of the corresponding media gateway in the bearer path is the same.

If the data encoding format of the connection endpoints on both sides of the media gateway is the same, the media gateway is deleted from the bearer path, and the bearer parameters of the bearer connection endpoint adjacent to the media gateway are updated. When the call is a call in the same exchange, and it is determined that the data encoding format of the bearer connection endpoints on both sides of the corresponding media gateway is the same, the media gateway is deleted from the bearer path, and the calling side or/and the called party are updated. The side access network device corresponds to the bearer parameter of the bearer connection end point on the network side, so that the bearer between the calling side and the called side access network device is directly interconnected.

When the call is an inter-exchange call, when the data encoding format of the connection endpoints on both sides of the calling side or/and the called side media gateway is the same, the corresponding calling side or/and the called side media gateway are slaved. The path is deleted, and the bearer parameters of the bearer connection endpoint on the relevant network side are updated.

When the data encoding format of the connection endpoints on both sides of the called media gateway is the same, and the data encoding format of the connection endpoints on both sides of the calling media gateway is different, the media gateway of the called side is deleted from the bearer path, and the called party is updated. The bearer connection endpoints on the network side and the bearer connection endpoints on the called side of the calling side media interface directly connect the bearer side access network device and the calling side media gateway.

If the data encoding format of the connection endpoints on both sides of the media gateway corresponding to the media gateway is the same, the called media gateway and the calling media gateway are respectively deleted from the bearer path, and the calling and called corresponding networks are updated. The bearer parameters of the bearer connection endpoints are such that the bearers between the calling and called access network devices are directly interconnected.

The call is an inter-office call through the tandem office. After the inter-office bearer path is established, it is determined whether the data encoding format of the bearer connection endpoints on both sides of the intermediate media gateway on the bearer path is the same. The media gateway is deleted from the bearer path;

Sending an update request message to the mobile softswitch corresponding to the intermediate media gateway.

The update request message is transmitted by the mobile softswitch corresponding to the upper-level media gateway to the mobile softswitch corresponding to the next-level media gateway;

The mobile softswitch at each level determines whether the data encoding formats of the endpoints on the two sides of the corresponding media gateway are the same. If they are the same, the corresponding media gateway is deleted in the bearer path.

Preferably, the method further comprises:

Before the bearer path is established, the codec capability of the access device on the calling side and the called side is compared, and if the same codec capability exists, the bearer connection is directly established between the calling device on the calling side and the access device on the called side. Establishing a playback channel between the calling side access device and the media gateway; otherwise, establishing a bearer connection between the primary and the called side access devices through the media gateway on the network side; The bearer connection includes: establishing a voice channel directly between the calling side access device and the called side access device, and a sound playing channel established between the calling side access device and the media gateway.

According to the present invention, there is also provided a bearer path management device, which is generally disposed in a central office device, and includes:

a bearer establishing module, configured to acquire information of the calling side access device and the called side access device, and control the call side access device, the called side access device, and the media gateway to establish a bearer; the determining module is configured to compare and determine the call Whether the coding and decoding capabilities of the side access device and the called side access device are the same and/or determining whether the data encoding format of the connection endpoints on both sides of the media gateway is the same, and transmitting the judgment result information to the bearer update module;

The bearer update module controls the bearer path adjustment between the call side access device and the called side access device according to the judgment result information of the judging module.

The device also includes:

The resource management module controls, according to the bearer path adjustment information, the bearer resource established between the corresponding media gateway and the source access device and the called side access device.

Preferably, when the determining module determines that the data encoding format of the bearer connection endpoints on both sides of the media gateway in the bearer path is the same, the bearer update module deletes the media gateway from the bearer path, and updates with the media gateway. The neighboring parameter that carries the connection endpoint.

Preferably, when the determining module determines that the coding capability of the calling side access device is the same as that of the called side access device, the bearer update module separately sends the endpoint information of the called side access device to the calling side access device, and The called side access device sends the endpoint information of the source access device, and controls the direct connection between the calling side access device and the called side access device.

According to another aspect of the present invention, a method for call connection is provided, comprising the steps of: comparing a codec capability list of a primary called side access device, and if the same codec exists, directly establishing a calling and called side Bearer between access devices;

Otherwise, the bearer between the calling and called access devices is established through the media gateway MGW on the network side.

The directly establishing the bearer between the access device and the access device includes: establishing a voice channel between the access device on the calling and called sides, and establishing a sound channel between the MGW and the access device.

The primary and the called side access devices are within the same MSCe coverage, and the MSCe compares the main A list of codec capabilities of the called side access device.

Preferably, when the same codec capability exists, the MSCe carries the IP endpoint information of the called side access device and the code supported by the calling and the called side access device in the bearer information sent to the calling side access device. The decoding capability is to establish a voice channel and carry the IP endpoint information of the MGW to establish a playback channel.

Preferably, when the same codec capability exists, the MSCe carries the IP endpoint information of the calling side access device and the code supported by the calling and side access devices in the bearer information sent to the called side access device. Decoding capability to establish a voice channel.

Preferably, after the deleting the playback channel between the calling side access device and the MGW, the following steps are included:

The calling side MSCe releases the IP endpoint resources on the calling side MGW;

The calling side MSCe notifies the called side MSCe to release the playback channel;

The called side MSCe releases the IP endpoint resource on the called side MGW.

According to still another aspect of the present invention, a method for implementing inter-office handover is provided, including: when a mobile station switches from a source office to a target office, the source-side mobile switching center requests a source-side media gateway according to a handover request of the source-side base station. Allocating a first IP endpoint, and sending the information of the first IP endpoint and the codec list provided by the source office to the target side mobile switching center;

The target side mobile switching center directly establishes an IP bearer between the IP endpoint of the target side base station and the first IP endpoint.

In summary, in the case that the data encoding formats of the connection endpoints on both sides of the media gateway in the bearer path are the same, the corresponding media gateway is deleted from the bearer path, and the bearer adjacent to the media gateway is updated. The bearer parameter of the connection endpoint, or the bearer format of the call side access device and the called side access device is directly established, and the bearer path is directly established between the call side access device and the called side access device, The bearer resource is optimized, and the bearer resource of the media gateway is released after the bearer path is updated, thereby reducing the intermediate processing link of the media data stream, and saving the bearer resources of the media gateway, thereby improving the overall efficiency and performance of the network.

As mobile communication networks continue to evolve to all-IP networks, more and more operators tend to use a uniform coding format, and the possibility that both ends of the call can negotiate the same coding format is increasing, by adopting the bearer of the present invention. Path optimization to avoid user data passing through unnecessary MGW, It can effectively reduce the network load, reduce the packet delay, improve the call quality, reduce the occupation of resources on the MGW during long-distance calls, and reduce the possibility of routing bypass. DRAWINGS

1 is a schematic diagram of a network entity connection in which a control bearer separation architecture is used in the prior art, and an interface between the access network and the core network is IP;

2 is a schematic diagram of bearer loading after IP porting of port A in the prior art;

3 is a schematic diagram of inter-office IP bearer in the prior art;

4 is a flow chart of inter-office call signaling in the prior art;

5 is a schematic diagram of a data encoding format conversion function provided by a media gateway in the prior art; FIG. 6 is a schematic flowchart of a method in a specific embodiment of the present invention;

7 is a schematic flow chart of a method in another embodiment of the present invention;

8 is a schematic flow chart of a method in still another embodiment of the present invention;

FIG. 9 is a schematic flowchart of a method for a call passing through a tandem office according to an embodiment of the present invention; FIG. 10 is a flow chart of a method for performing bearer path optimization after a bearer update according to the present invention;

11 is a signaling flowchart of re-enabling a media gateway for service processing after performing bearer path optimization according to the present invention;

12 is a flow chart of a method for performing bearer path optimization in a call connection process according to the present invention;

13 is a schematic structural diagram of establishing a dual channel under an inter-office IP bearer in a preferred embodiment of the present invention;

14 is a flow chart of call setup signaling under an interoffice IP bearer according to the present invention; FIG. 15 is a flow chart of a method for optimizing end-to-end bearer path according to the present invention; FIG. 16 is a flowchart for implementing inter-office handover of a user according to the present invention. Time-out method for carrying out path update;

FIG. 17 is a schematic structural diagram of a bearer path management apparatus according to an embodiment of the present invention. detailed description

The invention is applied to a mobile communication network in which an interface between an access network and a core network is IP-based under a bearer control separation architecture, and the basic method is: establishing a two-way user data bearer path between the calling party and the called party After the path, the mobile softswitch determines whether the data encoding format of the bearer connection endpoints on both sides of the corresponding media gateway in the bearer path is the same. If yes, the media gateway is deleted from the bearer path, and the bearer path is updated with the media gateway. The bearer parameters of the neighboring bearer connection endpoint.

During the call setup process, the bearer is built through the media gateway, and the host and the called access network device are directly built to bear the bearer, mainly by playing the voice through the media gateway.

After the call is established, in most cases, the media gateway does not need to play the caller again. If the data encoding formats on both sides are the same, the media gateway performs transparent transmission, so the media gateway can be deleted from the bearer path.

In order to make the principles, features and advantages of the present invention clearer, the present invention will be described below based on different inter-network call conditions and media gateway conditions that need to be deleted.

Example 1

The primary called party belongs to a call within the same exchange.

For intra-office calls, when the calling party is in the same exchange, the situation is relatively simple; when the called party answers, if the mobile softswitch determines that the data encoding format of the bearer connection endpoints on both sides of the media gateway (MGW) is the same, that is, the calling party If the inbound data encoding format is the same as the data format of the called access side, the MGW controlled by the local office is deleted from the bearer path, and the bearer parameters of the bearer connection endpoint corresponding to the network side of the base station to which the calling party is called are updated, so that the calling party and the called party are The bearer is directly interconnected between the subordinate base stations.

Example 2

The caller belongs to a call in a different exchange under the same tandem office, and the called side media gateway is deleted.

Referring to FIG. 6, it is assumed that the data encoding format of the calling access side is EVRC, and the data encoding format of the media gateway and the called access side are both 13 Κ. In this case, the called side media gateway is deleted, and the specific process is as follows: :

1. The MSCe2 receives the Connect message of the BS2, and instructs the called user to respond;

2. MSCe2 determines that the data encoding format of the called media gateway MGW2 is the same, and can delete the MGW2 to perform the bearer path optimization, and send an UPDATE request message to the MSCel, where the SDP information corresponding to the network side endpoint 7 of the BS2 is carried;

3. The MSCel receives the SDP information of the endpoint 7 of the network side corresponding to the BS2, and determines the calling party medium. The data encoding format of the two sides of the body gateway MGW1 is different, indicating that the bearer path optimization of the MSG1 cannot be deleted, and the 200 OK response is returned to the MSCe2, and the SDP information of the endpoint 4 of the called side of the MGW1 is still carried.

4. The MSCe2 sends a Bearer Update Request message to the BS2, and converts the SDP information of the MGW1 corresponding to the endpoint 4 of the called side into a bearer parameter and carries it to the BS2;

5. The BS2 updates the peer IP address and port number saved by the bearer according to the bearer parameters in the Bearer Update Request message, and returns a Bearer Update Response message.

6. The MSCel receives the 200 OK response of the INVITE message returned by the MSCe2.

7. The MSCel sends a MODIFY message to the MGW1, and updates the RemoteSDP of the endpoint 4 on the called side of the MGW1 to the SDP information of the endpoint on the network side of the BS2;

8. MSCel receives the REPLY message returned by MGW1.

9. MSCe2 sends a SUBSTRACT message to MGW2, releasing two endpoints 5 and 6 assigned to the call on MGW2;

10. MSCe2 receives the REPLY message returned by MGW2.

11. MSCel returns ACK to MSCe2;

12. The establishment of the bidirectional bearer channel between the calling and called users is completed;

13. After the call ends, the called user hangs up, and MSCe2 receives the Clear Request message sent by BS2.

14. MSCe2 sends a Clear Command message to BS2.

15. The MSCel receives the BYE message sent by the MSCe2.

16. MSCel sends a Clear Command message to BS1;

17. MSCel receives the Clear Complete message returned by BS1;

18. The MSCel sends a BYE 200 OK response message to the MSCe2;

19. The MSCel sends a SUBSTRACT message to the MGW1, releasing the two endpoints 3 and 4 assigned to the call on the MGW1;

20. The MSCel receives the REPLY message returned by the MGW1.

21. MSCe2 receives the Clear Complete message returned by BS2.

According to the above description of the process, in the process, the MDM1 on the calling side is updated to the RemoteSDP corresponding to the endpoint on the called side, and the SDP is the corresponding endpoint on the network side of the called BS2. Update the peer address information stored in the called BS2 to update the SDP information of the called side endpoint of the MGW1 on the calling side, and delete the MGW on the called side from the call bearer path established by the calling party to implement the bearer. Path optimization.

Example 3

The caller belongs to a call in a different exchange under the same gateway, and deletes the caller-side media gateway.

Referring to FIG. 7, it is assumed that the data encoding format between the data format of the calling access side and the media gateway is EVRC, and the data encoding format of the called access side is 13K. In this case, the calling side media gateway is deleted. The specific process is as follows:

1. MSCe2 receives the Connect message of BS2, indicating that the called user answers.

2. It is determined that the data encoding format between the calling side MGW1 and the called side MGW2 is different from the data encoding format of the called access side, and the carrying path optimization of the MGW2 cannot be deleted, and an UPDATE message is sent to the MSCel, where the bearer is carried. The calling side MGW corresponds to the SDP information of the calling side endpoint 5;

3. After receiving the UPDATE message, the MSCel learns between the gateways: according to the encoding format, and compares with the encoding format of the calling access side, and finds that the two are the same, indicating that the bearer path optimization of the MSG1 can be deleted, and 200 OK for UPDATE is sent. The message arrives at MSCe2, where the BS1 carries the SDP information corresponding to the endpoint 2 on the called side;

4. MSCe2 sends a MODIFY message to MGW2, and updates the RemoteSDP modification of endpoint 5 to 200. The SDP information of BS 1 carried in the OK message is corresponding to the endpoint 2 of the called side.

5. MSCe2 receives the REPLY message returned by MGW2.

6. MSCe2 returns a 200 OK response of the INVITE;

7. MSCel sends an ACK message to MSCe2;

8. The MSCel sends a Bearer Update Request message to the BS1, and converts the SDP information of the MGW2 corresponding to the calling end endpoint 5 into the bearer parameter and carries it to the BS1;

9. BS1 updates its saved peer IP address and port number according to the bearer parameters in the Bearer Update Request message, and returns a Bearer Update Response message.

10. MSCel sends a SUBSTRACT message to MGW1, releasing MGW1 on the present Two endpoints 3 and 4 of the secondary call assignment;

11. MSCel receives the REPLY message returned by MGW1.

12. MSCel returns an ACK to MSCe2;

13. The two-way 7|c-bearing channel between the calling and called users is established;

14. After the call ends, the called user hangs up, and MSCe2 receives the Clear Request message sent by BS2.

15. MSCe2 sends a Clear Command message to BS2.

16. The MSCel receives the BYE message sent by the MSCe2.

17. MSCel sends a Clear Command message to BS1;

18. The MSCe 1 receives the Clear Complete message returned by the BS 1;

19. The MSCel sends a BYE 200 OK response message to the MSCe2;

20. MSCe2 sends a SUBSTRACT message to MGW2, releasing two endpoints 5 and 6 of the call distribution;

21. The MSCe2 receives the REPLY message returned by the MGW2.

11. MSCe2 receives the Clear Complete message returned by BS2.

According to the foregoing flow description, in the process, the RemoteSDP corresponding to the calling side endpoint of the called MGW2 is updated to the SDP information of the endpoint corresponding to the network side of the calling BS1, and the saved peer is saved in the calling BS1. The address information is updated to the SDP information of the MGW2 on the called side corresponding to the calling side endpoint, and the MGW on the calling side is deleted from the call bearer path established by the calling party to implement the bearer path optimization.

Example 4:

The caller belongs to a call in a different exchange under the same gateway, and deletes the situation of the called side and the calling side media gateway.

Referring to FIG. 8, it is assumed that the data bearer coding format between the calling access side and the called access side and the MGW is EVRC. In this case, the called side and the calling side media gateway can be deleted at the same time. as follows:

2. The MSCe2 determines that the data encoding format between the calling side MGW and the called side MGW is the same as the data encoding format of the called access side, and the carrying path of the MGW2 can be deleted. And sending an UPDATE (Update) request message to the MSCel, where the SDP information corresponding to the network side endpoint 7 of the BS2 is carried;

3. After receiving the UPDATE message, the MSCel determines that the data encoding format on both sides of the calling media gateway MGW1 is the same, indicating that the bearer path optimization of the MSG1 can be deleted, and the 200 OK response is returned to the MSCe2, and the SDP corresponding to the network side endpoint 2 of the BS1 is carried. information;

4. The MSCel sends a Bearer Update Request message to the BS1, and converts the SDP information of the endpoint 7 on the network side of the BS2 into a bearer parameter and carries it to the BS1;

5. BS1 updates its saved peer IP address and port number according to the bearer parameters in the Bearer Update Request message, and returns a Bearer Update Response message.

6. The MSCe2 sends a Bearer Update Request message to the BS2, and converts the SDP information of the endpoint 2 corresponding to the network side of the BS1 into a bearer parameter and carries it to the BS2;

7. The BS2 updates the peer IP address and port number saved according to the bearer parameters in the Bearer Update Request message, and returns a Bearer Update Response message.

8. The MSCel receives a 200 OK response of the INVITE message returned by the MSCe2.

9. The MSCel sends a SUBSTRACT message to the MGW1, releasing the two endpoints 3 and 4 assigned to the call on the MGW1;

10. MSCel receives the REPLY message returned by MGW1.

11. MSCe2 sends a SUBSTRACT message to MGW2, releasing two endpoints 5 and 6 assigned to the call on MGW2;

12. The MSCe2 receives the REPLY message returned by the MGW2.

13. MSCel returns ACK to MSCe2;

14. The two-way ^^ channel is established between the calling and called users;

15. After the call ends, the called user hangs up, and MSCe2 receives the Clear Request message sent by BS2.

16. MSCe2 sends a Clear Command message to BS2;

17. The MSCel receives the BYE message sent by the MSCe2.

18. MSCel sends a Clear Command message to BS1;

19. The MSCel receives the Clear Complete message returned by the BS1. 20, MSCel sends a BYE 200 OK response message to MSCe2;

21. MSCe2 receives the Clear Complete message returned by BS2.

According to the foregoing process description, in the process, the IP address and port number information of the endpoint corresponding to the edge of the peer BS are saved in the call bearer path established by the calling party and the called party in the calling side and the called side BS, respectively. The MGWs on the calling side and the called side are deleted to optimize the bearer path.

Example 5

The calling and called calls belong to different tandem offices, and the MGW that does not provide the media format conversion function is deleted from the bearer path.

Referring to FIG. 9, it is assumed that the bearer access side, the bearer coding format of the calling MGW and the MGW controlled by the gateway is EVRC (Enhanced Variable Rate Codec), and the MGW and the called party controlled by the tandem office The bearer coding format of the called MGW is 13K voice. The TC mentioned later refers to the MGW that provides the codec conversion function. The MGW provides the TC to indicate that the MGW code formats are different. The specific process is as follows:

1. MSCe3 receives the Connect message of BS3, indicating that the called user answers.

2. The MSCe3 judges that the controlled MGW3 does not provide the TC in the call path (the MGW3 has the same end coding format on both sides of the call:), and can delete the MGW3 from the call path and send an UPDATE (Update) request message to the MSCe2, where Carrying the SDP information corresponding to the network side endpoint 9 of the BS3; if the MSCe3 determines that the controlled MGW3 provides the TC in the call path, the same is sent to the MSCe2, which carries the SDP information corresponding to the calling end end point 7 of the MGW3;

3. If the MSCe2 receives the UPDATE message and determines that the controlled MGW2 provides the TC, it returns a 200 OK response of the UPDATE, where the MGW2 carries the SDP information corresponding to the endpoint 6 of the called side; generally, if the non-calling access side MSCe receives The UPDATE message is sent to the next MSCe on the calling side. If the MGW controlled by the MSCe does not provide the TC, that is, the controlled MGW can be deleted from the bearer path, the SDP information carried in the received UPDATE is used. As the SDP in the sent UPDATE message, the sent UPDATE message carries the SDP of the calling side endpoint of the controlled MGW, and returns a 200 OK response of the UPDATE message, where the controlled MGW carries the SDP information corresponding to the called side endpoint; The calling access side MSCe receives the UPDATE message and directly returns 200 OK. SDP information or BS side endpoint SDP information;

4. MSCe2 sends a MODIFY message to MGW2, and updates the RemoteSDP of the called end side 6 on the MGW2 to the SDP information of the endpoint 9 on the network side of the BS3;

5. MSCe2 receives the REPLY message returned by MGW2;

6. The MSCe2 sends an UPDATE (Update) request message to the MSCel, where the MGW2 carries the SDP information corresponding to the endpoint 5 of the calling side;

7. The MSC1 receives the UPDATE message, and determines that the MGW1 is the primary access side MSCe and the controlled MGW1 does not provide the TC in the call path, and returns a 200 OK response of the UPDATE, where the BS1 carries the SDP information corresponding to the called end 2 of the called side;

8. MSCe2 sends a MODIFY message to MGW2, and updates the RemoteSDP of the calling side endpoint 5 on the MGW2 to the SDP information of the endpoint 2 of the network side corresponding to BS1;

9. MSCe2 receives the REPLY message returned by MGW2;

10. MSCe3 sends a 200 OK response message of the INVITE request to MSCe2; l l. MSCe2 sends a 200 OK response message of the INVITE request to MSCel;

12. MSCel returns an ACK message to MSCe2;

13. MSCe2 returns an ACK message to MSCe3;

14. The MSCe3 sends a Bearer Update Request message to the BS3, and converts the SDP information of the MGW2 corresponding to the called end endpoint 6 into a bearer parameter and carries it to the BS3;

15. BS3 updates the peer information stored by the peer according to the bearer parameters in the Bearer Update Request message, and returns a Bearer Update Response message;

16. The MSCel sends a Bearer Update Request message to the BS1, and converts the SDP information of the MGW2 corresponding to the calling end endpoint 5 into a bearer parameter and carries it to BS1;

17. BS1 updates the stored end information of the bearer according to the bearer parameters in the Bearer Update Request message, and returns a Bearer Update Response message;

18. The establishment of the bidirectional bearer channel between the calling and called users is completed;

19. After the call ends, the called user hangs up, and MSCe3 receives the Clear Request message sent by BS3.

20. MSCe3 sends a Clear Command message to BS3; 21. MSCe2 receives the BYE message sent by MSCe3;

22. MSCe2 sends a BYE message to MSCel;

23. MSCel sends a Clear Command message to BS1;

24. MSCel receives the Clear Complete message returned by BS1;

25. MSCel sends a BYE 200 OK response message to MSCe2;

26. MSCe2 sends a BYE 200 OK response message to MSCe3;

27. MSCe2 sends a SUBSTRACT message to MGW2, releasing the two endpoints 5 and 6 assigned to the call on MGW2;

28. MSCe2 receives the REPLY message returned by MGW2;

29. MSCe3 receives the Clear Complete message returned by BS3.

Take the call through a gateway that controls the media gateway as an example to show how to remove the MGW that does not provide the voice codec (TC) from the bearer path. In practical applications, it is also possible to pass through multiple gateways and multiple intermediate media gateways, and the signaling control principle is similar. The update request message (UPDATE) is transmitted by the mobile softswitch corresponding to the upper-level MGW to the next-level MGW. Corresponding mobile softswitch; The mobile softswitch of each level determines whether the data encoding formats of the endpoints of the corresponding MGW are the same, and if so, the corresponding MGW is deleted in the bearer path.

After the media gateway is deleted, if the neighboring media gateway that still holds the bearer connection endpoint in the bearer path has been deleted, the bearer parameters of the bearer connection endpoint are updated, so that the base station to which the caller belongs and the bearer path are not deleted. The bearer is interconnected between the media gateway and the base station to which the called party belongs.

It should be noted that if the gateway only performs signaling and does not control the media gateway during the call, it only transmits the incoming and outgoing UPDATE messages and the 200 OK response of the UPDATE message, and does not judge or perform other operations.

Example 6

Referring to FIG. 10, it is assumed that the original two-way call bearer access side data encoding format is EVRC, the data encoding format between the media gateways is G.711, and the data encoding format of the called access side is 13K, after the call The bearer parameter change occurs, the data format of the calling access side data becomes SMV (Selectable Mode Vocoders), the data encoding format between the media gateways becomes SMV, and the data encoding format of the called access side is still 13K:

1. The establishment of the bidirectional bearer channel between the calling and called users is completed; 2, 3, bearer parameter negotiation modification process, the same as the prior art;

4. The MSCel determines that the data encoding format of the calling access side is the same as the data encoding format between the calling side MGW and the called side MGW, and can perform the bearer path optimization of deleting the MGW1, and send a re-I VITE message to the MSCe2. The SDP information of the endpoint 2 of the calling side BS is carried. 5. After receiving the re-INVITE message, the MSCe2 learns the data encoding format between the gateways and compares with the encoding format of the called access side, and finds that the two are different, indicating that the two cannot be performed. Deleting the bearer path optimization of the MGW2, sending a 200 OK for re-INVITE message to the MSCel, where the SDP information of the endpoint 5 corresponding to the calling side of the called side MGW2 is carried;

6. MSCel returns ACK to MSCe2 _;

7. The MSCel sends a Bearer Update Request message to the BS 1 , and converts the SDP information of the MGW 2 corresponding to the calling end endpoint 5 into a bearer parameter and carries it to the BS 1;

8. The BS1 updates the information of the peer 7 stored by the bearer according to the bearer parameter in the Bearer Update Request message, and returns a Bearer Update Response message.

9. MSCel sends a SUBSTRACT message to MGW1, releasing the two endpoints 3 and 4 of the call distribution;

10. MSCel receives the REPLY message returned by MGW1.

11. MSCe2 sends a MODIFY message to the MGW2, and updates the RemoteSDP modification of the endpoint 5 to 200. The SDP information of the BS 2 carried in the OK message is corresponding to the endpoint 2 of the called side.

12. MSCe2 receives the REPLY message returned by MGW2.

13. The calling party and the called party are still in the process of two-way conversation;

15. MSCe2 sends a Clear Command message to BS2.

16. The MSCel receives the BYE message sent by the MSCe2.

17. The MSCe 1 sends a Clear Command message to the BS 1;

18. MSCel receives the Clear Complete message returned by BS1.

19. The MSCel sends a BYE 200 OK response message to the MSCe2;

20. The MSCe2 receives the Clear Complete message returned by the BS2. 21, MSCe2 sends a SUBSTRACT message to MGW2, releasing the two endpoints 5 and 6 of the call distribution;

22. MSCe2 receives the REPLY message returned by MGW2.

According to the foregoing process description, in the process, after the one or a plurality of bearer coding formats that are carried by the service driver or other reasons are changed, the bearer path may be optimized by deleting the TC in the bearer path.

Example 7

In some cases, after the bearer optimization, the service may be required to perform playback, DTMF detection, and conference resource insertion. The operation is different. The MSCe processing is similar: Send an ADD message to the corresponding MGW. Apply for the corresponding endpoint. For the conference, you need to apply for the number of conference participants. Then, the SIP-based signaling and the Alp interface signaling are used to update the bearer parameters on the BS. The endpoints on the MGW are re-incorporated into the bearer path. The corresponding endpoint performs resource operations to complete the playback during the call, the DTMF detection report, and the insertion of conference resources. At the end of the call, each endpoint requested on the MGW will be released. Referring to Figure 11, after the bearer optimization is performed, the calling MSCe controls the internal tone of the calling party to be briefly described as an example. The processing flow is as follows:

1. The calling party and the called party enter the two-way call state, and the BS directly bears the interconnection, and no MGW exists in the bearer path;

2. The MSCel sends an ADD message to the MGW1, requesting to allocate two RTP endpoints, corresponding to the bearer connection endpoints on the BS1 side and the called side respectively;

3. The MSCel receives the REPLY message returned by the MGW1, and carries the SDP information of the two RTP endpoints that are applied for, respectively, including the coding format supported by the MGW1, the IP address and port number of each endpoint;

4. The MSCel sends a Bearer Update Request message to the BS1, and converts the SDP information corresponding to the BS1 endpoint of the MGW1 into a bearer parameter and carries it to the BS1;

5. The BS1 updates the peer IP address and port number saved according to the bearer parameters in the Bearer Update Request message, and returns a Bearer Update Response message.

6. The MSCel sends a re-INVITE message to the MSCe2, and carries the SDP parameter corresponding to the called terminal 4 on the MGW1. 7. The MSCe2 sends a Bearer Update Request message to the BS2, and converts the SDP information of the MGW1 corresponding to the called end endpoint 4 into a bearer parameter and carries it to the BS2;

8. The BS2 updates the peer IP address and port number saved by the bearer according to the bearer parameters in the Bearer Update Request message, and returns a Bearer Update Response message.

9. The MSCe2 returns a 200 OK response of the re-INVITE message to the MSCel, and carries the SDP information of the BS2 near the endpoint 7 of the calling side;

10. MSCel sends an ACK message to MSCe2.

11. The MSCel sends a MODIFY message to the MGW1, and updates the RemoteSDP corresponding to the called side end point 4 of the MGW1 to the SDP information of the end point Ί of the network side of the called BS2;

12. The MSCel receives the REPLY message returned by the MGW1.

13. MSCel sends a MODIFY message to MGW1 to play the sound in endpoint 3;

14. The MSCel receives the REPLY message returned by the MGW1.

15. The one-way bearer establishment of the MGW1 to the calling user;

16. MSCel sends a MODIFY message to MGW1 to stop playback of endpoint 3;

17. The MSCel receives the REPLY message returned by the MGW1.

18. At the end of the playback, the calling party and the called party re-enter the two-way call state.

It can be seen from the above specific example process that when the primary called party establishes a two-way user data bearer path through a normal call procedure or changes a certain or a certain number of bearer codes in the bearer path, the mobile softswitch initiates the bearer path. The removal of the media gateway (MGW) that does not provide the voice codec from the bearer path can reduce the packet delay and improve the call quality. During the long-term two-way call, the MGW endpoint can be fully utilized to improve the utilization of the MGW resource.

Example 8

In the call setup process, bearers can also be established directly between the primary and the called access network devices. However, two bearer channels need to be built: one directly establishes a bearer between the primary and the called access network devices, and the other is a playback channel between the media gateway and the calling access network device (for playback:).

The mobile access softswitch controls the calling access network device to activate, deactivate, and release the channel. During the call setup process, the playback channel is activated, and the master and the called are deactivated; W

-21 - After the call is connected, the playback channel is released, and the bearer channel between the master and the called party is activated.

In order to save intermediate processing links during the call connection process, thereby saving system resources, referring to FIG. 12, the bearer path optimization is performed in the call connection process according to the present invention, and the call connection process includes the following steps:

Sl, the calling side access device initiates a call.

52. The MSCe compares the codec capability list of the access device on the calling and the called side. If the same codec exists, the process proceeds to step S3. Otherwise, the media gateway MGW on the network side establishes the connection between the access device on the calling and the called side. .

53. Establish a voice channel directly.

S4. The MSCe controls the attributes of the channel to complete the ringing to answering conversion.

S5. After the two-way conversation, release the playback resources of the MGW.

For the intra-office call, the MSCe compares the codec capability list of the access device on the calling side. If the same codec capability exists, the calling side establishes two channels: a playback bearer between the access device and the MGW. Channel, used for playback; a voice bearer channel between the calling side access device and the called side access device, used for; The called side only establishes a voice bearer channel between the calling side access device and the called side access device for carrying voice. During the establishment of the bearer, the playback channel is activated and the voice channel is deactivated. After the called party answers, delete the playback channel on the calling side and activate the voice bearer channel.

When inter-office call is connected, an inter-office negotiation process is required. Referring to FIG. 13 and FIG. 14, the SIP protocol is extended. The prior art only carries bearer information of one channel, and the method of the present invention carries bearer information of two channels (ie, voice channel and sound channel). The INVITE message sent by the calling side to the called side carries the IP endpoint information of the calling side BSC and the codec capability list supported by the calling side BSC, and has the IP endpoint information of the calling side MGW and the calling side MGW support. A list of codec capabilities. The called side MSCe compares the codec capability list of the called side BSC and the calling side BSC. If the same codec capability exists, the bearer information sent to the called side BSC directly carries the IP endpoint information of the calling side BSC. Instead of carrying the IP endpoint information of the MGW, that is, the voice channel between the calling and called BSCs is directly established without the MGW. Then, the MGW is built to the calling channel of the calling party.

In this embodiment, the interoffice call connection includes the following specific steps: Step S201: The calling side access device initiates a call.

1. The calling side BSC sends a CM Service Req message to the calling side MSCe, where the message carries the IP address, port number and supported CODEC list carried by the calling side BSC.

2. The calling side MSCe sends an ADD Req message to the calling side MGW, requesting to apply for 2 IP endpoints; an IP endpoint is the IP endpoint (IP endpoint 3) of the calling side BSC, which contains the IP address of the calling side BSC. The port number and the CODEC supported by the calling side BSC and the calling side MGW; the other IP endpoint is the interoffice IP endpoint (IP End 4).

3. After the calling party MGW allocates the IP endpoint, it returns the assigned IP endpoint information to the calling side MSCe, and the calling side MSCe records the returned IP endpoint information.

4. The calling side MSCe sends an Assignment Request message to the calling side BSC, where the message carries the IP address, the port number of the IP endpoint 3 allocated by the calling side MGW, and the CODEC supported by the calling side BSC and the calling side MGW.

5. The calling side MSCe sends an INVITE message to the called side MSCe, where the message carries two channel information: one channel is the information of the IP endpoint 2 of the calling side BSC and the CODEC list supported by the calling side BSC; one channel is The information of the IP endpoint 4 of the calling side MGW and the CODEC list supported by the calling side MGW.

6. The called side MSCe sends a paging message to the called side BSC.

7. After the calling side BSC establishes the air interface channel and the IP bearer, the calling side BSC sends an Assignment Complete message to the calling side MSCe, and the playback channel between the calling side BSC and the calling side MGW is completed.

8. The called side BSC sends a paging response message to the called side MSCe, where the message carries the IP endpoint information (IP endpoint Ί) carried by the called side BSC and the CODEC list supported by the called side BSC.

At this time, the called side MSCe has learned the capability information of the primary and called side BSCs, and compares the CODEC list supported by the primary and called side BSCs. If the same codec exists, the end-to-end negotiation passes, and the process proceeds to step S203. Otherwise, according to the existing process, the 7?c load between the calling and called BSCs is established by the MGW.

Step S203: Establish a voice channel directly.

9. The called side MSCe sends an ADD Req message to the called side MGW to apply for one. The IP endpoint (IP endpoint 5) to be played to the user, the message carrying the IP endpoint information (IP endpoint 4) of the calling side MGW, and indicating to the IP endpoint 5 to put back the ring tone.

10. The called side MGW allocates the IP endpoint 5 and returns it to the called side MSCe. The called side MSCe records the IP address and port number of the called side MGW.

11. The called side MSCe sends an Assignmet Request message to the called side BSC, where the message carries the information of the IP endpoint 2 of the calling side BSC and the CODEC jointly supported by the calling and called parties.

12. The called side MSCe sends a 180 message to the calling side MSCe, where the message carries the endpoint information of the two channels: one is the IP endpoint information (IP endpoint Ί) of the called side BSC and the CODEC jointly supported by the calling and called sides , used to establish a voice channel between the calling and called BSCs; a message for the called side interoffice IP endpoint 5, used to establish a playback channel.

15. The calling side MSCe sends a MODIFY message to the calling side MGW, and the information of the IP address 5 of the end office of the 4th station informs the IP end point 4 that the inter-office playback bearer channel is established by the calling side MGW.

16. The calling side MGW returns a response message.

17. After the playback bearer is built, the called party will return the ring tone to the caller.

18. The calling side MSCe sends a BEARER UPDATE REQUEST message to the calling side BSC, where the message carries two IP endpoint information, and the first IP endpoint information includes: information of the IP endpoint 3, the IP endpoint is a playback endpoint, and the attribute is The second IP endpoint information includes: information of the IP endpoint 7, the endpoint is a voice endpoint (ie, the IP endpoint of the called side BSC), and the CODEC supported by the calling and called parties, and the attribute is deactivated.

19. The calling side BSC sends a BEARER UPDATE RESPONSE message to the calling side MSCe.

20. After the called side BSC establishes the air interface channel and the IP bearer, it sends an Assignment Complete message to the called side MSCe.

Step S204: The MSCe controls the attributes of the channel to complete the ringing to answering conversion. 21. After the called party answers, the called side BSC sends a CONNECT message to the called side MSCe.

22. The called side MSCe sends a 200 message to the calling side MSCe, where the message carries the IP endpoint information (IP endpoint Ί) of the called side BSC.

23. The calling side MSCe sends a BEARER UPDATE REQUEST message to the calling side BSC, informing the calling side BSC to delete the playback channel and activate the voice channel. 24. The calling side BSC releases the playback channel, activates the voice channel, and sends a BEARER UPDATE RESPONSE message to the calling side MSCe.

25. The calling side MSCe sends an ACK message to the called side MSCe, where the message carries the IP endpoint information (IP endpoint 2) of the calling side BSC.

Step S205: Release the playback resource of the MGW after the two-way conversation.

26. The calling side BSC releases the playback channel, activates the voice channel, and sends a BEARER UPDATE RESPONSE message to the calling side MSCe, and the calling side MSCe notifies the calling side MGW to release the network side playback channel.

28. The called side MSCe notifies the called side MGW to release the network side playback channel after receiving the calling party ACK.

Example 9

In addition, according to the present invention, an end-to-end bearer path optimization method can be provided, and the bearer can be directly established between the primary and the called access network devices without using the media gateway, and the called terminal directly plays the sound to the calling side. Referring to Figure 15, specifically:

1. The calling BSC sends a CM Service Req message to the MSCe, which is carried by the BSC side.

IP address, port number, list of supported Codec;

2. The MSCe sends a paging request message to the called side BSC;

3. The called BSC gives the MSCe paging response message, with the IP address and port number carried by the BSC side, and the supported Codec list; and the flag supports the called terminal to support returning the ring tone to the calling party;

4. The MSCe determines the Codec list of the primary and the called BSC. If there is a commonly supported Codec, the MME does not request the IP endpoint to be carried. The MSCe sends an assignment request message to the calling side BSC, with the IP of the called side BSC. Address, port number, common supported Codec;

5. The MSCe sends an assignment request to the called BSC, with the IP address and port number of the calling side BSC, and the commonly supported Codec; the primary and the called BSC directly interact to establish a DP bearer. At the same time, the parameter in the assignment request message requires the called terminal to directly put back the ring tone to the calling terminal.

6. 7. The master and the called party send the assignment completion message to the MSCe.

8. After the bearer between the air interface channel and the BSC is established, the called terminal directly returns the ring to the calling party. 9. The called party answers, the called terminal stops putting back the ring tone, and the master and the called party make a normal call. The primary and the called BSC interact directly, which reduces unnecessary intermediate processing links, especially when the primary and the called are in the same BSC, which can improve the voice quality.

When the called party is connected, it is no longer necessary to modify the bearer, and the situation that the called party is not able to hear the sound for a short period of time is avoided. The called party directly plays the calling party, and the user can set the characteristic ring back tone for different calling users on the terminal.

Example 10

A bearer path update scheme when an inter-office handover of a user is implemented in a mobile communication system according to the present invention.

In the talk state, the user switches, and the bearer needs to be built from the new access network device.

First, the source side BS sends a handover request to the source side MSCe, and the source side MSCe requests the source side MGW to allocate a first IP endpoint, such as the IP endpoint 7, to establish a bearer with the target office, and the information and source of the first IP endpoint. The codec (CODEC) list provided by the office is sent to the target side MSCe. Refer to Figure 16, as follows:

Step 1: The source side BS sends a request for handover to the source side MSCe (HANDOFF)

REQUIRED ) message, the message includes a hard handover candidate cell list;

Step 2: The source side MSCe establishes bearer information on the source side MGW by sending an ADD command, and requires the source side MGW to allocate the first IP endpoint 7 for contacting the target office. Step 3: The source side MGW sends a reply (Reply) The message confirms the join result, the reply message includes the assigned IP address and port number of the first IP endpoint 7; 'Step 4, the source side MSCe sends a FACDIR2 ( Facilities Directive2 INVOKE device indication) message to the target office MSCe;

Step 5: The source side MSCe sends an initial call (INVITE) message to the target office MSCe, where the initial call message carries the information (including the IP address and port number) of the first IP endpoint 7 of the source side MGW and the CODEC list provided by the source office.

Next, in step 6-12, an IP bearer is established directly between the source side MGW and the target side BS. In this process, the target side BS selects the CODEC from the CODEC list provided by the source office. among them: Step 6: After receiving the FACDIR2 message and the initial call message sent by the source side MSCe, the target side MSCe sends a handover request (HANDOFF REQUEST) message to the target side BS, where the handover request message carries information of the first IP endpoint 7 of the source side MGW. ;

Step 7, the target side BS sends the information of its IP endpoint 10 and its CODEC list to the target side MSCe through the handover request response message; after receiving the handover request response message, the target side MSCe sets the CODEC list of the target side BS therein. The CODEC list provided by the source office compares, if the same CODEC exists, then selects the same CODEC, step 8, the target side MSCe sends a facdir2 ( Facilities Directive2 RETURN RESULT device indication response) message to the source side MSCe;

Step 9, the target side MSCe sends the information of the IP endpoint 10 of the target side BS and the CODEC selected by the target side BS directly to the source side MSCe via the 200 OK message;

Step 10: The source side MSCe sends the information of the IP endpoint 10 of the target side BS to the source side MGW by using a modify (MODIFY) message, and updates the bearer information of the MGW.

Step 11: The source side MGW establishes an IP bearer between the first IP endpoint 7 and the IP endpoint 10 of the target side BS, and notifies the source side MSCe by using a Reply message.

Step 12: The source side MSCe sends an acknowledgement (ACK) message to the target side MSCe to notify the IP bearer between the source side MSCe source side MGW first IP end point 7 and the target side BS IP end point 10.

After the IP bearer between the source office and the target office is established, in step 13-20, the handover adjustment of the mobile station from the source side BS to the target side BS is completed. among them:

Step 13: The source side MSCe sends a HANDOFF COMMAND message to the source side BS and causes the MS to switch through the BS.

Step 14, when the MS has started the handover, the source side BS sends a HANDOFF COMMENCED message to the source side MSCe;

Step 15. After the MS switches to the target office, the target side BS sends the handover completion.

( HANDOFF COMPLETE ) message to the target side MSCe;

Step 16, the target side MSCe sends the mobile station entry channel to the source side MSCe (Mobile On Channel, MSONCH) message, to indicate that the handover of the target office is completed; Step 17, when the source side MSCe receives the MSONCH mobile station incoming channel message, the handover succeeds, and the source side MSCe sends a subtract (SUBTRACT) command to the source side MGW. Let it be removed to the bearer path of the IP endpoint 5 of the source side MGW;

The bearer path before handover is: the IP endpoint on the access side 6 to the IP endpoint 5 on the MGW, the IP endpoint 5 on the MGW to the IP endpoint 4, and the IP endpoint 4 interacts with the other party on the call.

After the handover is completed, IP endpoint 4 is connected to IP endpoint 7, and IP endpoint 7 is to the new access side IP endpoint 10. Access device IP endpoint 6 and IP endpoint 5 on the MGW are no longer needed and should be removed.

Step 18, after the handover is completed (step 16), the source side MSCe sends a clear command.

(CLEAR COMMAND) to the source side BS;

Step 19: The source side MGW sends a reply message to the source side MSCe, and confirms that the bearer path of the IP end point 5 has been removed;

Step 20: The source side BS sends a CLEAR COMPLETE message to the source side MSCe in response to the clear command.

As shown in FIG. 17, in the embodiment of the present invention, a bearer path management device 01 is generally provided in the central office device, and specifically includes:

The bearer establishing module 02 is configured to acquire the information of the calling side access device and the called side access device, and control the call side access device, the called side access device, and the media gateway to establish a bearer; Comparing and determining whether the coding and decoding capabilities of the calling side access device and the called side access device are the same and/or determining whether the data encoding format of the bearer connection endpoints on both sides of the media gateway is the same, and transmitting the judgment result information to the bearer update module;

The bearer update module 04 controls the bearer path adjustment between the call side access device and the called side access device according to the judgment result information of the judging module.

The device also includes:

The resource management module 05 controls, according to the bearer path adjustment information, the bearer resources established between the corresponding media gateway and the source access device and the called side access device.

When the determining module determines the number of connection endpoints carried on both sides of the media gateway in the bearer path According to the same encoding format, the bearer update module deletes the media gateway from the bearer path, and updates relevant parameters of the bearer connection endpoint adjacent to the media gateway.

When the determining module determines that the encoding capability of the calling side access device is the same as that of the called side access device, the bearer update module sends the endpoint information of the called side access device to the calling side access device, and connects to the called party. The inbound device sends the endpoint information of the source access device, and controls the direct connection between the calling side access device and the called side access device.

When the mobile station switches between the source side office and the target station, the mobile station exchanges the bearer information of the source side media gateway and the target side base station through the target side mobile switching center, directly between the source side media gateway and the target side base station. The IP bearer is set up, and the IP bearer is not required to be established between the source-side media gateway and the target-side media gateway and the target-side media gateway, so that the source-side media gateway can directly interact with the target-side base station without using the target-side media gateway. Therefore, the bearer processing is optimized, the intermediate processing link is reduced, the media stream information transmission quality is improved, and the target side media gateway bearer resources are saved.

The above embodiments are presented to illustrate and explain the principles of the invention. It will be understood that the specific embodiments of the present invention are not limited thereto. Various changes and modifications may be made without departing from the spirit and scope of the invention.

Claims

Rights request

A method for optimizing a bearer path, comprising:

If the data encoding format of the connection endpoints on both sides of the media gateway is the same, the media gateway is deleted from the bearer path, and the bearer parameters of the bearer connection endpoint adjacent to the media gateway are updated.

2. The method according to claim 1, wherein the call is a call in the same exchange, and the data encoding format of the bearer connection endpoints on both sides of the corresponding media gateway is determined to be the same, then the media gateway is from the The bearer path is deleted, and the bearer parameters of the bearer connection end point corresponding to the network side of the calling side access device or the called side access network device are updated, so that the bearer between the calling side and the called side access network device is directly interconnected.

3. The method according to claim 1, wherein the call is an inter-exchange call, and when the data encoding format of the connection endpoints on both sides of the calling side or/and the called side media gateway is the same, the corresponding call is performed. The calling side or/and the called side media gateway are deleted from the bearer path, and the bearer parameters of the bearer connection end point on the relevant network side are updated.

The method according to claim 3, wherein when the data encoding format of the connection endpoints on both sides of the called media gateway is the same, and the data encoding formats of the connection endpoints on both sides of the calling media gateway are different, The called side media gateway is deleted from the bearer path, and the bearer connection end point corresponding to the network side and the bearer connection end point of the calling media gateway corresponding to the called side are updated, so that the called side access network device and the calling side are The media gateways carry direct interconnections between them.

The method of claim 4, wherein the deleting the called side media gateway and updating the bearer parameters comprises the following steps:

The called side mobile softswitch sends an update request message to the calling side mobile softswitch, and carries the session description protocol SDP information corresponding to the network side endpoint of the called side base station BS;

The calling side mobile softswitch returns a response message to the called side mobile softswitch, and 'carrying the calling side media gateway corresponding to the SDP information of the called side endpoint;

The called side mobile softswitch sends a media update request message to the called side base station BS, carrying the main The called side media gateway corresponds to the bearer parameter of the SDP information converted by the called side end point; the called side base station BS updates the saved peer address information by using the bearer parameter carried in the media update request message;

The calling side softswitch sends a modification message to the calling side media gateway, and updates the remote SDP corresponding to the called side endpoint to the SDP information of the network side endpoint corresponding to the called side base station BS; the called side mobile softswitch sends the delete message. To the called side media gateway, the two endpoints allocated by the called side media gateway for the call are forwarded, and the called side media gateway is deleted from the bearer path; the called side base station BS corresponds to the network side endpoint and the calling side media. The gateway is directly interconnected with the called side endpoints.

The method according to claim 3, wherein when the data encoding format of the connection endpoints on both sides of the called media gateway is different, and the data encoding formats of the connection endpoints on both sides of the calling media gateway are the same, The calling side media gateway is deleted from the bearer path, and the bearer connection end point corresponding to the network side of the calling party and the bearer connection end point corresponding to the calling side of the called side media gateway are updated, so that the calling side access network device and the called party are called. The side media gateways carry direct interconnections between them.

The method according to claim 6, wherein the deleting the calling side media gateway and updating the bearer parameters specifically includes the following steps:

The calling side mobile softswitch sends a re-request message to the called side mobile softswitch, and carries the SDP information of the network side endpoint corresponding to the calling side BS;

The called side mobile softswitch determines a return response message, and carries the SDP information corresponding to the calling side endpoint of the called side media gateway;

The called side mobile softswitch sends a modification message to the called side media gateway, and updates the remote SDP corresponding to the calling side endpoint on the MGW to the SDP information of the network side endpoint corresponding to the calling side base station BS;

The calling side mobile softswitch sends a media update request message to the calling side base station BS, and carries the bearer parameter converted by the SDP information of the calling side end point corresponding to the calling side media gateway;

The calling side base station BS updates the saved peer address information by using the bearer parameter carried in the media update request message sent by the calling side mobile softswitch;

The calling side mobile softswitch sends a delete message to the calling side media gateway, releasing the calling side medium The two endpoints allocated for the call on the body gateway are deleted from the bearer path of the calling side media gateway; the network side endpoint of the calling side base station BS and the calling side endpoint corresponding to the called side media gateway are directly interconnected.

The method according to claim 3, wherein if the data encoding format of the connection endpoints on both sides of the media gateway corresponding to the called side and the calling side is the same, the called side media gateway and the calling side media gateway are The bearer parameters of the bearer connection endpoints on the network side of the calling party and the called party are updated respectively, so that the bearers between the calling party and the called access network device are directly interconnected.

The method of claim 8, wherein the deleting the called side media gateway and updating the bearer parameters specifically includes the following steps:

The called side mobile softswitch sends an update request message to the calling side mobile softswitch, and carries the session description protocol SDP information corresponding to the network side endpoint of the called side BS;

The calling side softswitch returns a response message to the called side softswitch, and carries the SDP information of the network side endpoint corresponding to the calling side BS;

The calling side mobile softswitch sends a media update request message to the calling side BS, carrying the called side

The bearer parameter corresponding to the SDP information converted by the network side endpoint;

The called side mobile softswitch sends a media update request message to the called side BS, and carries the bearer parameter of the SDP information converted by the calling side BS corresponding to the network side end point;

The called side base station BS updates the saved peer address information by using the bearer parameter carried in the media update request message sent by the called side mobile softswitch;

The calling side mobile softswitch sends a delete message to the calling side media gateway, and releases the two endpoints allocated for the call on the calling side media gateway, and deletes the calling side media gateway from the bearer path;

The called side mobile softswitch sends a delete message to the called side media gateway, releasing the two endpoints allocated for the call on the called side media gateway, and deleting the called side media gateway from the bearer path; the calling side base station BS The endpoints on the corresponding network side are directly interconnected with the endpoints on the network side corresponding to the called side base station BS.

The method according to claim 1, wherein the call is an inter-office call through the tandem office, and after the inter-office bearer path is established, determining that the intermediate media gateway on the bearer path carries the connection on both sides Whether the data encoding format of the endpoint is the same, if the same, the intermediate media gateway is deleted from the bearer path;

The method of claim 10, wherein the update request message is transmitted by a mobile softswitch corresponding to the upper-level media gateway to a mobile softswitch corresponding to the next-level media gateway;

12. The method of claim 1, further comprising:

Before the bearer path is established, the codec capability of the access device on the calling side and the called side is compared, and if the same codec capability exists, the bearer connection is directly established between the calling device on the calling side and the access device on the called side. Establishing a playback channel between the calling side access device and the media gateway; otherwise, establishing a bearer connection between the primary and the called side access devices through the media gateway on the network side;

The bearer connection includes: establishing a voice channel directly between the calling side access device and the called side access device, and a sound playing channel established between the calling side access device and the media gateway.

13. The method of claim 12, wherein

During the call setup process, the playback channel between the calling side access device and the media gateway is activated, and the bearer channel of the primary and the called access device is deactivated;

After the call is established, the playback channel is played and the bearer channel between the master and the called party is activated.

The method of claim 12, wherein the directly establishing a bearer connection between the calling and the called side access devices comprises:

The bearer information sent to the access device on the calling side carries the IP endpoint information of the access device on the called side and the codec supported by the access device on the called side, and the bearer information is sent to the access device on the called side. Carrying the IP endpoint information of the calling side access device and the codec supported by the calling and receiving side access devices to establish a voice channel;

The bearer information sent to the calling side access device carries the IP endpoint information of the corresponding media gateway to establish a playback channel.

15. The method of claim 14 wherein:

The bearer information sent to the calling side access device carries the playback channel attribute information between the calling side access device and the media gateway, and between the calling side access device and the called side access device. Voice channel attribute information.

16. A bearer path management device, comprising:

a bearer establishing module, configured to acquire information of the calling side access device and the called side access device, and control the call side access device, the called side access device, and the media gateway to establish a bearer; the determining module is used for comparing and determining Whether the coding and decoding capabilities of the calling side access device and the called side access device are the same and/or determining whether the data encoding format of the bearer connection endpoints on both sides of the media gateway is the same, and transmitting the judgment result information to the bearer update module;

17. The device of claim 16, further comprising:

18. Apparatus according to claim 16 wherein:

When the determining module determines that the data encoding format of the bearer connection endpoints on both sides of the media gateway in the bearer path is the same, the bearer update module deletes the media gateway from the bearer path, and updates the bearer connection adjacent to the media gateway. The relevant parameters of the endpoint.

19. Apparatus according to claim 16 wherein:

20. A method of call connection, characterized in that it comprises the following steps:

Comparing the codec capability list of the primary and the called side access devices, if there is the same codec, directly establishing the bearer between the primary and the called side access devices;

Otherwise, the media gateway MGW on the network side establishes the connection between the calling and the calling devices on the calling side.

The method according to claim 20, wherein the directly establishing the bearer between the access devices on the called and the called side comprises: establishing a voice channel between the access devices on the calling and called sides, and establishing an MGW and accessing Playback channel between devices.

The method according to claim 20, wherein the calling and called side access devices are within the same MSCe coverage, and the MSCe compares the codec capability list of the access device on the calling side.

The method according to claim 22, wherein, when the same codec capability exists, the MSCe carries the IP endpoint information of the called side access device in the bearer information sent to the calling side access device. The codec capability supported by the primary and secondary called side access devices to establish a voice channel and carry the IP endpoint information of the MGW to establish a playback channel.

The method according to claim 22, wherein, when the same codec capability exists, the MSCe carries the IP endpoint information of the calling side access device in the bearer information sent to the called side access device. The codec capability supported by the primary and secondary side access devices to establish a voice channel.

The method according to claim 23, further comprising: in the connection process, the bearer information sent by the MSCe to the calling side access device includes: placing between the calling side access device and the MGW The audio channel attribute is activated, and the voice channel attribute between the calling side access device and the called side access device is deactivated.

The method according to claim 24, further comprising: deleting the playback channel between the calling side access device and the MGW after the called party answers,

The MSCe releases the IP endpoint resources on the corresponding MGW.

The method according to claim 22, wherein, when the primary and the called side access devices are within different MSCe coverage, the called side MSCe compares the codec capability of the primary and the called side access devices. List.

The method according to claim 27, wherein the called side MSCe compares the codec capability list of the primary called side access device, and the following steps are included:

The bearer information sent by the calling side MSCe to the called side MSCe carries the IP endpoint information of the calling side access device and the codec capability list supported by the calling side access device, and the IP endpoint information and the main party of the calling side MGW. Calling the side MGW to support the codec capability list; The called side MSCe obtains the IP endpoint information of the called side access device and the codec capability list supported by the called side access device from the called side, and the IP endpoint information of the called side MGW and the called side MGW support codec. List of capabilities;

The called side MSCe completes the comparison of the codec capability list of the primary and the called side access devices.

The method according to claim 27, wherein when the same codec capability exists, the called side MSCe carries the IP endpoint of the calling side access device in the bearer information sent to the called side access device. Information and codec capabilities supported by the primary and secondary side access devices to establish a voice channel.

The method according to claim 27, wherein, when the same codec capability exists, the called side MSCe carries the IP endpoint information of the called side access device in the bearer information sent to the calling side MSCe. The codec capability supported by the primary and secondary side access devices is used to establish a voice channel; and the IP endpoint information carrying the MGW on the called side and the MGW on the calling and called sides jointly support the codec capability list to establish a playback channel.

The method according to claim 30, wherein the calling side MSCe sends the IP endpoint information of the called side access device sent by the called side MSCe and the codec capability supported by the calling and called access devices. Send to the calling side access device.

The method according to claim 29, 30 or 31, wherein, in the connection process, the bearer information sent by the calling side MSCe to the calling side access device includes: the calling side access device and the MGW The playback channel attribute between the activation is activated, and the voice channel attribute between the calling side access device and the called side access device is deactivated.

The method according to claim 29, 30 or 31, wherein after the called party answers, the bearer information sent by the calling side MSCe to the calling side access device comprises: deleting the calling side access device and The playback channel between the MGWs, and the voice channel attribute between the calling side access device and the called side access device are activated.

The method of claim 33, wherein after deleting the playback channel between the calling side access device and the MGW, the method includes the following steps:

The called side MSCe releases the IP endpoint resource on the called side MGW.

35. A method for implementing inter-office handover, comprising: when a mobile station switches from a source office to a target office, the source-side mobile switching center requires the source-side media gateway to allocate the first according to the handover request of the source-side base station. An IP endpoint, and sending the information of the first IP endpoint and the codec list provided by the source office to the target side mobile switching center;

The method of claim 35, further comprising: directly establishing an IP bearer between the IP endpoint of the target side base station and the first IP endpoint, specifically:

Receiving, by the target side base station, information of the first IP endpoint sent by the target side mobile switching center and a codec list provided by the source office;

The target side base station selects a codec from the codec list, and sends information of its IP endpoint and its selected codec to the target side mobile switching center;

The target side mobile switching center sends the received information of the target side base station IP endpoint and the codec selected by the target side base station to the source side mobile switching center;

Transmitting, by the source side mobile switching center, information of the target side base station IP endpoint to the source side media gateway;

The source side media gateway establishes a bearer between the first IP endpoint and the target side base station IP endpoint.

37. The method of claim 36, wherein

The information of the first IP endpoint is carried in a handover request message;

The information and the codec list of the target side base station IP endpoint are carried in the handover request response message.

38. The method of claim 36, wherein

The information of the target side base station IP endpoint and the codec selected by the target side mobile switching center are carried in a 200 OK message.

39. The method of claim 36, wherein

The information of the target side base station IP endpoint is carried in the modification message.

40. The method of claim 36, wherein

The information of the first IP endpoint includes at least an IP address and a port number of the first IP endpoint; and the information of the target side base station IP endpoint includes at least an IP address and a port number of the target side base station IP endpoint.