CN1878405A - Method for A-Flex circuit domain network realizing switching between bureaus and its system - Google Patents

Abstract

The invention discloses a method and system for realizing inter-office handover in an A-Flex circuit domain network. The method includes the following steps: a. After the handover function entity HF receives the inter-office handover request message from the mobile switching center MSC According to the information carried in the handover request message, establish a handover session, and select the target side core network node to send the interoffice handover request message to it; b. the target side core network node receives the interoffice After the handover request message, the handover is completed. The method of the present invention effectively reduces the number and complexity of switching paths and data configurations required for in-pool and out-of-pool switching, and facilitates capacity expansion and data maintenance. Adding MSCs in the pool only needs to increase the switching path from the MSC to the HF And related data, the external connection relationship and data configuration remain unchanged, that is, it is transparent to other pools, effectively reducing the complexity of operation and maintenance.

Description

A method and system for implementing inter-office handover in an A-Flex circuit domain network

technical field

The present invention relates to the technical field of A-Flex, in particular, to the technology of inter-office handover under the A-Flex architecture.

Background technique

In a network that does not support flexible interfaces between the access network and the core network, one mobile switching center (MSC) can connect to multiple base station controllers (BSC), but one base station controller can only connect to one mobile switching center. The connection relationship between the MSC and the BSC in the CDMA2000 circuit domain network under this architecture is shown in Figure 1 .

This 1:N relationship between the mobile switching center and the base station controller restricts the flexibility of the networking. First, the user capacity of the MSC is getting larger and larger. When an MSC is shut down for maintenance, is seriously overloaded or fails , all the BSCs connected to the MSC will lose their function, and the users within the wireless range covered by all the BSCs connected to the MSC will not be able to communicate with the circuit business, which will have a great impact on the users and cannot be tolerated by the operator; secondly, If it is necessary to add an MSC node to the existing network due to user capacity expansion, at least one BSC device must be added at the same time (even if the access network coverage and user processing capacity are sufficient), otherwise the new MSC will not work.

Under the A-Flex (Ainterface Flexibility A interface flexible) architecture, a BSC can connect to multiple MSCs at the same time. After an MSC device is upgraded and maintained, overloaded or crashed, other available MSCs connected to it will be covered by the BSC. user services within. The A-Flex mechanism itself makes it possible to redistribute and balance the load among multiple MSC nodes, and it can also effectively avoid the overload of a single node.

The A-Flex networking is shown in Figure 2, where the scope of the pool (pool) consists of the wireless coverage of at least one (usually multiple) BSCs, and the multiple BSCs are shared by all MSCs (at least two) in the pool Serve. You can see that each BSC in the pool is connected to all MSCs in the pool, and you can choose among all MSCs. In the figure, MSC5 and its connected BSC7 and BSC8 represent MSC and BSC nodes outside the pool that do not support the A-Flex feature.

In the A-Flex network, when a certain MS roams in the pool, all the core network processing processes are carried out on a specific CN (core network) node in the pool, that is, for a single MS, there is only one "ownership" in the pool "CN processing node, this method can avoid frequent location updates; and for all MSs in the pool, they are divided into different "home" CN nodes, so the load is shared.

In the field of WCDMA technology, Iu-Flex (Iu interface Flexibility Iu interface flexibility, corresponding to the A-Flex mentioned above, is the flexibility of the interface between the access network and the circuit domain core network) has become a standardized technology. In the core network of CDMA2000 circuit domain, A-Flex technology can also be used.

In a pool supported by A-Flex, any MSC is connected to all BSCs in the pool, so the handover between two BSCs in the pool becomes an intra-office handover, and only the handover between two BSCs across the pool becomes an inter-office handover .

In order to ensure the handover between BSCs across pools, the WCDMA technical standard stipulates that each MSC in a pool is connected to at least one MSC in another pool where it may be handed over, and the relevant handover data is configured; in order to ensure that the BSCs in the pool For handover with BSCs outside the pool that do not support A-Flex features, it is also required that each MSC in the pool be connected with all MSCs outside the pool that do not support A-Flex features but may be handed over, and configure relevant handover data. The specific connection relationship is shown in Figure 3:

In order to complete the handover from BSC6 to the adjacent BSC0, it is necessary to configure No. Data, configure switching path No. 4 and related data on MSC1, configure switching path No. 5 and related data on MSC2; switch from BSC3 to BSC7, configure switching path No. 6 and related data on MSC0, configure switching path No. 7 and For related data, switch path No. 8 and related data are configured on MSC2. Similarly, for switching from BSC7 to BSC3, switch path No. 9 and related data need to be configured on MSC5. Only one realizable configuration is shown in the figure, and the MSC connection switching paths in the selection pool are all optional, so there are many other configuration combinations.

It can be seen that only considering the handover between adjacent BSC3 and BSC7, and between BSC6 and BSC0, many handover path connections and configurations are required. If the adjacent BSCs of other BSCs are also considered, the number of connections and configurations It is very large; and after the number configuration is completed, if the network expands and an MSC is added in a pool, it is necessary to increase the connection and configuration with adjacent pools, which will not only affect the connection relationship of the pool, but also affect the adjacent pools. It is very inconvenient to maintain; in addition, the flexibility and diversity of configuration combinations also bring considerable difficulties to modify data.

Contents of the invention

The purpose of the present invention is to provide a method and system for implementing inter-office handover in an A-Flex circuit domain network, so as to solve the problem of complicated operation and maintenance of the existing inter-office handover system.

In order to achieve the above object, the technical solution provided by the present invention is as follows: A method for realizing inter-office handover in an A-Flex circuit domain network, the method includes the following steps:

a. After receiving the inter-office handover request message from the mobile switching center MSC, the handover functional entity HF establishes a handover session according to the information carried in the handover request message, and selects the core network node on the target side and sends the office handover request to it. switching request message;

b. The core network node at the target side completes the handover after receiving the inter-office handover request message.

The steps before step a also include: configuring handover data between the HF and the MSC under the softswitch architecture, and configuring handover data and switching circuits between the HF and the MSC under the traditional circuit switching architecture.

Wherein step a specifically includes:

a1. When receiving the inter-office handover request message sent by the MSC on the source side, the HF analyzes the handover target address in the inter-office handover request message, and forwards the inter-office handover signaling to the HF after addressing the target side;

Wherein step b specifically includes:

b1. The HF in the target pool selects the MSC in the pool according to the policy to perform the handover process, and forwards the inter-office handover request message to it;

b2. The selected MSC determines the target BSC and sends a handover request message to it to complete the handover.

The selection of MSCs in the pool according to the strategy in step b1 specifically refers to selection of MSCs in the pool according to load balancing round-robin or optional or according to the geographic location where the target BSC is located.

Wherein step a specifically includes:

a1. When receiving the inter-office handover request message sent by the MSC on the source side, the HF analyzes the handover target address in the inter-office handover request message, and forwards the inter-office handover signaling to it after addressing the target MSC;

Wherein step b specifically includes:

After receiving the inter-office handover request message, the MSC determines the target BSC, and sends the handover request message to it to complete the handover.

Under the traditional circuit switching architecture, the inter-office handover request message is the mobile application part MAP inter-office handover request message, and under the softswitch architecture, the inter-office handover request message is the MAP inter-office handover associated with the virtual circuit number vCIC Request message and Session Initiation Protocol SIP Session Request message.

Wherein, before step a1, it also includes: the MSC on the source side receives a handover request message sent by the BSC, the message carries the target MSC identity and cell information, and the MSC judges that the target MSC is not in the pool, then sends the message to the the HF.

The above method further includes: after the HF receives the message related to the subsequent inter-office handover, forwarding the message according to the information of the established handover session.

The handover session information established by the HF includes: the source-side core network node information, the target-side core network node information, and the current handover user identifier.

The present invention also provides an A-Flex circuit domain network system for realizing inter-office handover, including an A-Flex pool composed of a BSC and an MSC, and the A-Flex pool also includes a handover functional entity HF connected to the MSC, It is used for addressing and forwarding the inter-office handover signaling after parsing the inter-office handover signaling and performing handover session management.

The HF described therein also has a media gateway management function when used in time division multiple access TDM and IP hybrid networking.

Among them, multiple HFs are configured in one A-Flex pool, which are mutual backups, and there are interfaces between the HFs, which are used to synchronize information from the active HF to the standby HF.

The information that the active HF synchronizes with the standby HF specifically refers to data or data and handover session information.

The present invention also provides a functional entity HF for realizing inter-office handover under the A-Flex framework, characterized in that the entity is connected to the MSC in the A-Flex pool to resolve the inter-office handover signaling and then address and forward the Inter-office handover signaling and handover session management.

The present invention overcomes the deficiencies of the prior art. By adding a handover functional entity HF in the A-Flex pool, the handover functional entity is connected with the mobile switching center or other handover functional entities in the network, and is used for analyzing inter-office handover signaling, addressing and forwarding Inter-office handover signaling and handover session management function. Effectively reduce the number and complexity of handover paths and data configuration required for in-pool and out-of-pool handover, facilitate capacity expansion and data maintenance, add MSCs in the pool, only need to add handover paths and related data from the MSC to the HF, external connection relationship and The data configuration remains unchanged, that is, it is transparent to other pools, effectively reducing the complexity of operation and maintenance.

Description of drawings

Figure 1 is a schematic diagram of the connection relationship between MSC and BSC in the existing CDMA2000 circuit domain;

Figure 2 is a schematic diagram of the A interface connection relationship between the MSC and the BSC under the A-Flex architecture;

FIG. 3 is a schematic diagram of a handover path in the prior art across pools;

Fig. 4 is a system diagram of the present invention;

Fig. 5 is a system diagram of configuring standby HF in the present invention;

FIG. 6 is a flowchart of Embodiment 1 of the present invention;

FIG. 7 is a flowchart of Embodiment 2 of the present invention;

Fig. 8 is a flow chart of the third embodiment of the invention.

Detailed ways

The basic principle of the present invention is to configure a handover function entity (HandooffFunction, HF) in each A-Flex pool for the processing of cross-pool handover. The handover target address in the inter-office handover request message is addressed to the target HF or MSC according to the configuration. When the HF receives the inter-office handover message from other HFs, it selects an MSC in the pool according to the strategy. The inter-office handover message of the HF interacts with the target BSC according to the existing flow to complete the handover.

The system diagram of technical solution of the present invention is as shown in accompanying drawing 4:

Among them, each A-Flex pool is configured with a handover functional entity HF, which is connected to the MSC in the pool and interconnected with HFs in other pools. MSC5, BSC7, and BSC8 represent MSCs and BSCs outside the pool that do not support A-Flex. , at this time HF is directly connected with MSC5.

To complete the handover between BSC6 and BSC0, it is necessary to configure No. 1 handover path and related data between MSC3 and HF0, configure No. 2 handover path and related data between MSC4 and HF0, and configure No. 7 handover between HF0 and HF1 Paths and related data, No. 3 switching path and related data are configured between MSC0 and HF1, No. 4 switching path and related data are configured between MSC1 and HF1, No. 5 switching path and related data are configured between MSC2 and HF1; BSC3 and BSC7 To switch between MSC5 and HF1, it is necessary to configure No. 6 switch path and related data between MSC5 and HF1. When it is necessary to add an MSC in the domain, it only needs to increase the switching path connection and related data with the HF in the local pool, without affecting the external performance. Because the connection relationship is fixed, all the switching paths shown in the figure are bidirectional.

The handover function entity has functions of analyzing inter-office handover signaling, addressing and forwarding inter-office handover signaling and handover session management according to the handover target address therein. When it is connected with Circuit-Switched MSC (traditional circuit-switched mobile switching center), it also has the function of managing switching circuits in the case of TDM networking.

The HF described in the present invention can be configured with two in each A-Flex pool, and they are mutual backups, as shown in Figure 5: initially, HF0 and HF1 are respectively active in the two pools, and when the active one fails, Then the standby is automatically upgraded to the active one. If HF0 is normal and HF1 is faulty, when BSC6 to BSC0 cross-pool handover, if HF1 fault is detected, HF0 will send an inter-office handover request message to the standby handover entity HF1', and HF1' will assist in completing the cross-pool handover. If HF0 is faulty and HF1 is normal, when the cross-pool handover from BSC6 to BSC0 is detected, the handover anchor MSC will send an inter-office handover request message to the standby handover entity HF0', and HF0' will assist in completing the cross-pool handover. The other fault condition combinations are similar. There is an interface between the active HF and the standby HF for synchronizing information from the active to the standby. There are two cases here:

1) Only the backup data configuration is synchronized from the master to the backup, and only when the master data changes, the backup is notified for backup. When the master fails, the ongoing switchover will be affected

2) In addition to synchronizing backup data configuration to the backup, the master also synchronizes switching session information in real time. When the master fails, the backup can take over from the master to process the current switching.

Embodiment 1: Traditional circuit domain TDM networking, the flow chart of handover between pools is shown in Figure 6:

At this time, switching circuits are configured between MSC4 and HF1, between HF1 and HF2, and between HF2 and MSC5, and HF has the function of switching circuit management.

1. MSC4 receives the Handoff Required (handover request) message from BSC6, which carries target MSC information and cell information;

2. MSC4 judges that the target MSC is not in its own pool, then sends an interoffice handover message FACDIR2 (device indication) to the handoff functional entity Handoff Function 1 (HF1) of this pool, and FACDIR2 carries the interoffice handoff circuit identifier CIC1 allocated by MSC4;

3. Handoff Function 1 receives the FACDIR2 message, analyzes the target MSCID (mobile switching center identifier), and judges that it belongs to the pool where Handoff Function 2 is located, then forwards the message to HandoffFunction2, which carries the inter-office handover circuit identifier CIC2 allocated by HF, and Handoff Function1 needs to be established Handover session, the record includes source side MSC4 information, target side HF2 information and current handover user identification, such as the user's International Mobile Subscriber Identity IMSI and other handover session information, in order to realize the forwarding of this handover follow-up message;

4. Handoff Function 2 selects MSC0 in the pool for this handover process according to the policy (according to load balancing round-robin or optional or according to the geographical location of the target BSC), and forwards the inter-office handover message to MSC0, which carries the inter-office handover circuit Identify CIC3, and establish a handover session, record including source side HF1 information, target side MSC0 information, current handover user identification, such as IMSI and other handover session information, in order to realize the forwarding of subsequent messages of this handover;

5. MSC0 finds the target BSC according to the cellID (cell identifier), and sends a HandoffRequest message to BSC0;

6. BSC0 returns a Handoff Request ACK (handoff request response) message to MSC0;

7. MSC0 returns the facdir2 message to Handoff Fundion 2;

8. Handoff Function 2 returns facdir2 message to Handoff Function 1;

9. Handoff Function 1 returns facdir2 message to MSC4;

10. MSC4 sends a Handoff Command message to BSC6;

11. BSC6 sends a Handoff Commenced message to MSC4 to start the handover:

12. After the handover is completed, MSC0 receives the Handoff Complete message from BSC0;

13. MSC0 returns MSONCH (mobile station access channel) message to Handoff Function 2;

14. Handoff Function 2 returns MSONCH message to Handoff Function 1;

15. Handoff Function 1 returns MSONCH message to MSC4;

16-17. MSC4 removes the call at the source side;

18. After switching, the communication between the target side and the remote end continues;

19. The handover target side initiates a disconnection process, and MSC0 receives the Clear Request (clear request) message from BSC0;

20. MSC0 sends a FACREL (equipment release) message to HF2;

21. HF2 forwards the FACREL message to HF1 according to the recorded switching session information;

22. HF1 forwards the FACREL message to MSC4 according to the recorded switching session information;

23. MSC4 sends a Clear Command (clear command) message to BSC6 to remove the remote end (this process assumes that the remote end user is also under BSC6);

24. BSC6 returns a Clear Complete message to MSC4;

25-27. Facrel returns to MSC0 according to the original route sent by FACRE;

28. MSC0 sends a Clear Command message to BSC0;

29. BSC0 returns a Clear Complete message to MSC0;

Embodiment 2: Under the mobile softswitch architecture, the process of switching from the MSCe in the pool to the MSCe outside the pool that does not support the A-Flex feature is shown in Figure 7, wherein the process of MSCe managing the media gateway belongs to the prior art, and in the figure and Not reflected in the corresponding explanatory text:

In order to complete the handover between MSCe2 (mobile softswitch center) in the pool and MSCe5 outside the pool that does not support the A-Flex feature, the handover data is configured between HF1, MSCe2 and MSCe5, when it is applied to the softswitch after the inter-office signaling interface is IP-based When connecting to the network, the HF must also have the ability to process SIP signaling related to inter-office handover.

1. MSCe2 receives the Handoff Required message from BSC3, which carries the target location area cell information;

2. MSCe2 judges that the target location area cell is not in its own pool, then sends the inter-office handover message FACDIR2 to the connected handoff function entity Handoff Function1, which carries vCIC for associating MAP (Mobile Application Part) messages and SIP (Session Initiation Protocol) messages (virtue CIC (virtual circuit number);

3. MSCe2 sends an INVITE (session invitation) message to HF1, which carries the local SDP1 (Session Description Protocol) and the association identifier vCIC;

4. Handoff Function 1 receives the FACDIR2 message, analyzes the cell information of the target location area, forwards the FACDIR2 message to the target mobile switching center MSCe5, and records handover session information (such as source MSC4 information, target side HF2 information and user identification), in order Realize the forwarding of subsequent messages of this handover;

5. Handoff Function 1 receives the INVITE message and forwards it to the target mobile switching center MSCe5;

6. MSCe5 finds the target BSC according to the found cell information, and sends a HandoffRequest message to BSC7;

7. BSC7 returns a Handoff Request ACK message to MSCe5;

8. MSCe5 returns facdir2 message to HF1;

9. MSCe5 returns a 200OK message to HF1, carrying the target SDP;

10. HF1 returns the facdir2 message to MSCe2;

11. HF1 returns a 200OK (successful response to the INVITE request) message to MSCe2, carrying the target side SDP;

12. MSCe2 returns an ACK message to HF1;

13. HF1 returns an ACK message to MSCe5;

14. MSCe2 sends a Handoff Command message to BSC3;

15. BSC3 sends a Handoff Commenced message to MSCe2 to start switching;

16. After the handover is completed, MSCe5 receives the Handoff Complete message from BSC7;

17. MSCe5 returns MSONCH message to HF1;

18. HF1 returns MSONCH message to MSCe2;

19-20. MSCe2 disconnects the source-side call;

21-32. The process of disconnecting the call after switching and the completion of the call.

Embodiment 3: In the case of mixed networking of traditional circuit switching and mobile softswitch equipment, the process of switching from the MSCe in the pool to the MSC outside the pool that does not support the A-Flex feature is shown in Figure 8, wherein the process of MSCe managing the media gateway belongs to Prior art, which is not reflected in the drawings and corresponding explanatory texts:

In order to complete the handover between the MSCe2 (Mobile Soft Switch Center) in the pool and the traditional circuit switching MSC5 outside the pool that does not support the A-Flex feature, the handover data is configured between HF1, MSCe2 and MSC5, and HF1 further needs to have a media gateway management and handover circuit management functions.

1. MSCe2 receives the Handoff Required message from BSC3, which carries the target location area cell information;

2. MSCe2 judges that the target location area cell is not in its own pool, then sends the interoffice handover message FACDIR2 to the connected handoff function entity Handoff Function 1, which carries information for associating MAP (Mobile Application Part) messages and SIP (Session Initiation Protocol) messages vCIC(virtue CIC(virtual circuit number);

3. MSCe2 sends an INVITE (session invitation) message to HF1, which carries the local SDP1 (Session Description Protocol) and the association identifier vCIC;

4. Handoff Function 1 receives the FACDIR2 message, analyzes the cell information of the target location area, judges that the mobile switching center on the target side is MSC5, interacts with the downlink media gateway MGW, and obtains the IP endpoint (corresponding to SDP2) and TDM endpoint (corresponding to CIC1) assigned by the MGW )

5. Handoff Function 1 forwards the FACDIR2 message to MSC5, which carries the switching circuit identifier CIC1, and establishes a switching session, records the switching session information including the source side MSCe2 information, the target side MSC5 information, and the current user ID, in order to realize the follow-up message of this switching forwarding;

6. MSC5 finds the target BSC according to the found cell information, and sends a HandoffRequest message to BSC7;

7. BSC7 returns a Handoff Request ACK message to MSC5;

8. MSC5 returns facdir2 message to HF1;

9. HF1 returns the facdir2 message to MSCe2;

10. HF1 returns a 200OK (successful response to the INVITE request) message to MSCe2, carrying the IP endpoint information SDP2 of the MGW;

11. MSCe2 returns an ACK message to HF1;

12. MSCe2 sends a Handoff Command message to BSC3;

13. BSC3 sends a Handoff Commenced message to MSCe2 to start switching;

14. After the handover is completed, MSC5 receives the Handoff Complete message from BSC7;

15. MSC5 returns MSONCH message to HF1;

16. HF1 returns MSONCH message to MSCe2;

17-18. MSCe2 removes the call at the source side;

19-29. The call after switching and the disconnection process after the call is completed.

Claims (14)

1, a kind of A-Flex circuit-domain network realizes the method for inter-office switchover, it is characterized in that described method comprises following step:

A, handover (mih) functions HF receive behind the inter-office switchover request message of moving exchanging center MSC according to the information of carrying in the described handoff request message, set up and switch session, and send described inter-office switchover request message to it behind the select target side core net node;

After b, described target side core net node are received the inter-office switchover request message, finish switching.

2, method according to claim 1, it is characterized in that, wherein also comprise before the step a: under the soft-exchange construction, between HF and moving exchanging center MSC, dispose switch data, under the legacy circuit-switched framework, configuration switch data and commutation circuit between HF and moving exchanging center MSC, HF has the commutation circuit management function.

3, method according to claim 1 is characterized in that, wherein step a specifically comprises:

A1, when receiving the inter-office switchover request message that source MSC sends, HF resolves the switching target address in the inter-office switchover request message, is addressed to behind the target side HF hand off signaling between its reforwarding office;

Wherein step b specifically comprises:

HF carries out this hand-off process according to the MSC in the policy selection pond, handoff request message between its reforwarding office in b1, the object pool;

B2, described selected MSC determine to send handoff request message to it behind the target BS C, finish switching.

4, method according to claim 3 is characterized in that, wherein step b1 is described specifically refers to according to load balancing polling or optional or select MSC in the pond according to the geographical position at target BS C place according to the MSC in the policy selection pond.

5, method according to claim 1 is characterized in that, wherein step a specifically comprises:

A1, when receiving the inter-office switchover request message that source MSC sends, HF resolves the switching target address in the inter-office switchover request message, transmits described inter-office switchover signaling to it after being addressed to target MSC;

Wherein step b specifically comprises:

MSC determines target BS C after receiving described inter-office switchover request message, and sends described handoff request message to it, finishes switching.

6, method according to claim 1, it is characterized in that, under the legacy circuit-switched framework, described inter-office switchover request message is a MAP MAP inter-office switchover request message, under soft-exchange construction, described inter-office switchover request message is with the MAP inter-office switchover request message of virtual circuit vCIC association and Session initiation Protocol SIP conversation request message.

7, according to claim 3 or 5 described methods, it is characterized in that, wherein also comprise before the step a1: source MSC receives the handoff request message that BSC sends, carry target MSC sign and cell information information in the described message, MSC judges that target MSC not in the pond, then sends to described HF with described message.

8, method according to claim 1 is characterized in that, also comprises: HF transmits described message according to the information of the switching session of being set up after receiving follow-up inter-office switchover related news.

9, method according to claim 8 is characterized in that, the switching session information that described HF set up comprises: the user ID of described source core network nodes information, target side core network nodes information and current switching.

10, a kind of A-Flex circuit-domain network realizes the system of inter-office switchover, comprise the A-Flex pond of forming by BSC and MSC, it is characterized in that, also comprise the handover (mih) functions HF that links to each other with MSC in the described A-Flex pond, be used for resolving the inter-office switchover signaling after addressing transmit described inter-office switchover signaling and switch session management.

11, system according to claim 10 is characterized in that, described HF also has the media gateway management function when being used for time division multiple access TDM and IP mixed networking.

According to claim 10 or 11 described systems, it is characterized in that 12, described HF disposes a plurality of, backups each other, and has interface between the described HF in an A-Flex pond, use HF to standby HF synchronizing information with the cause master.

13, system according to claim 12 is characterized in that, described master it is believed that breath or data and switches session information to the concrete index of the synchronous information of standby HF with HF.

14, a kind of A-Flex framework is realized down the functional entity HF of inter-office switchover, it is characterized in that, described entity link to each other with MSC in the A-Flex pond be used for resolving the inter-office switchover signaling after addressing transmit described inter-office switchover signaling and switch session management.

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