CN100401807C - A Method for Establishing Shared Links in Digital Trunking System - Google Patents

Abstract

The present invention discloses a method for establishing a shared link in a digital cluster system. The method comprises: a) after receiving an establishing request of a cluster call, a wireless access network (RAN) judges that whether the current call is the first time call in the current call cluster group; if yes, a link is established for the current call, and the current processing is ended; otherwise, step b is performed; b) the wireless access network judges that whether the cluster group establishes a link; if yes, the information of the current call is added in the information of the established link, and the current processing is ended: otherwise, the current call is cached; c) the wireless access network judges that if the current link is established successfully or not; the cached call information is added to the successfully established link information; if failing, the wireless access network releases the current cached call. The method of the present invention can reduce loss probability and avoid the repetition establishment of the shared link, and accordingly the present invention improves the quality of service.

Description

A Method for Establishing Shared Links in Digital Trunking System

technical field

The invention relates to the realization technology of the service link in the digital trunking system, in particular to the establishment method of the shared link in the digital trunking system.

Background technique

At present, the push-to-talk (PTT, Push-to-Talk) service applied to collaborative work and communication among teams, working groups, and groups refers to real-time point-to-point and point-to-multipoint voice communication. This service adopts half-duplex mode, that is, only one person can speak at the same time, and the calling party can initiate a call to one person or a group by pressing a special key, without dialing and waiting for the other party to pick up the phone, and the call is connected immediately. Thus quickly establishing a conversation group.

When implementing digital trunking services in CDMA, CDMA 2000 or CDMA 1X systems, the trunking service data is transmitted through the packet network, and the mobile terminal (MS) interacts with the packet network for signaling and data through the radio access network (RAN). In order to realize the transmission of data between the RAN and the packet network, it is necessary to establish data links between entities inside the RAN and between entities of the RAN and the packet network during the signaling interaction process of call establishment. Within the RAN, entities related to processing cluster services mainly include: Base Station Controller (BSC) and Packet Control Function (PCF) entities; and functional entities related to cluster service processing on the packet network are PTT servers (PS, PTTServer). Among them, the BSC is responsible for receiving signaling and data from the MS side into packet data packets, and sending them to the PCF. At the same time, it also receives packet data packets from the PCF and assembles them into service frames for distribution to each MS; the PCF is responsible for packet data services. Signaling and data processing, and overall management and control of the data link; PS, as the control center of the trunking service, controls the trunking service call, and is responsible for media stream distribution and other work.

Since the trunking service adopts the half-duplex communication mode, only one person can speak at the same time. In order to realize one person speaking and multiple people listening, it is necessary to send the speaker's voice data to the PS dedicated to processing the trunking service, and the PS transmits the voice data through the RAN distributed to individual listeners. In this way, in a call of the same cluster group, the same data is sent on the reverse link from the talker MS to the PS, and on each forward link from the PS to each listener MS. Therefore, in order to save link resources and speed up call establishment, when the RAN receives a trunk call, it will establish a shared link for calls of the same trunk group.

In the existing cluster call shared link establishment process, the BSC inside the RAN judges after receiving the cluster call establishment request: whether the current call is the first cluster call establishment request of the cluster group under the BSC, if so , the BSC interacts with the PCF, assigns a new A8 link identifier, and establishes an A8 link; otherwise, the current call information is added to the A8 link information that the BSC has established for the cluster group; and, the PCF in the RAN receives After the A8 link establishment request, it is judged whether the current call is the first A8 link establishment request of the cluster group, if so, the PCF interacts with the PS, assigns a new GMP link identifier, and establishes a GMP link; otherwise, the current The call information is added to the GMP link information that the PCF has established for the cluster group.

Wherein, when the BSC and the PCF establish a new A8 link, the BSC sends an A8 link establishment request to the PCF, such as A9 establishes an A8 message A9-Setup-A8, and until the BSC successfully receives the A8 link connection response returned by the PCF, For example, when A9 connects with A8 message A9-Connect-A8, the A8 link is successfully established. If the BSC does not receive the A9-Connect-A8 message within the specified time, it means that the A8 link is not successfully established.

Thus, problems arise when multiple users of the same cluster group initiate call setup requests at the same time. For example: after BSC sends A9-Setup-A8 to PCF for the first call of the trunk group, BSC receives the second call of the trunk group without receiving the A9-Connect-A8 message returned by PCF At this time, the BSC will decide not to establish the A8 link for this second call establishment request, and the second call will share the same A8 link with the first call; but if the BSC does not The A9-Connect-A8 message corresponding to the first call is received, indicating that the A8 link of the first call has not been successfully established. At this time, the second call and subsequent calls of the trunk group will also have no usable link , which will cause a large number of call losses for the cluster group.

The prior art also provides another method for establishing a trunked call shared link, which is similar to the above-mentioned shared link establishment process, the difference being that the judgment is: the BSC judges whether it has successfully established the trunking group for the current call An A8 link; the PCF judges whether it has successfully established a GMP link for the current call trunking group.

Problems can also arise when using this shared link establishment method to establish a trunked call. For example: when the BSC sends A9-Setup-A8 to the PCF for the first call of the trunk group, and does not receive the A9-Connect-A8 message returned by the PCF, the BSC receives the second call setup of the trunk group At this time, since the BSC has not successfully established the A8 link for the trunking group, it will decide to establish the A8 link for the second call; but then if the BSC receives the corresponding The A9-Connect-A8 message indicates that the A8 link of the first call is successfully established. At this time, the second call, and possibly even subsequent calls of the cluster group, have started to establish the A8 link. In this way, the BSC will repeatedly establish the A8 link for the calls of the same trunk group, which cannot truly realize the link sharing of the trunk call and waste system link resources.

When the GMP link between the PCF and the PS is established, a similar problem to the above-mentioned A8 link establishment process will also occur.

It can be seen that the current method for establishing a shared link in a digital trunking system is likely to cause a large number of call losses or repeated establishment of a shared link when multiple trunking calls are centralized, which seriously affects the quality of trunking services and cannot effectively utilize system resources. .

Contents of the invention

In view of this, the main purpose of the present invention is to provide a method for establishing a shared link in a digital trunking system, which can ensure that each call of the trunking service can have an available link, and avoid repeated establishment of the shared link, thereby improving service quality and save link resources.

In order to achieve the above object, technical solution of the present invention is achieved in that way:

The invention discloses a method for establishing a shared link in a digital trunking system. The method includes:

a. After the RAN receives the cluster call establishment request, it judges whether the current call is the first call of the current call cluster group, if yes, establishes a link for the current call, and ends the current processing; otherwise, execute step b;

b. Determine whether the cluster group has established a link, if so, add the current call information in the information of the established link, and end the current processing; otherwise, cache the current call;

c. Judging whether the current link establishment is successful or failed, if successful, adding the cached call information to the information of the successfully established link; if failing, releasing the currently cached call.

In step c, before releasing the current cached call, the method further includes:

c1. Determine whether the number of link establishment times has reached the preset threshold of link establishment times, if yes, release the remaining calls buffered, and end the current processing; otherwise, execute step c2.

c2. Extract a call from the cached calls, establish a link for the call, and record the number of link establishments;

c3. Judging whether the link establishment described in step c2 is successful or failed, if successful, adding the buffered remaining call information to the information of the successfully established link; if failed, returning to step c1.

Wherein, the established link is: a GMP link between the PCF in the RAN and the external PS;

In step a: the cluster call setup request received by the RAN is the A8 link setup request received by the PCF; the judgment is: the PCF judges whether the current call is the first A8 link setup request of the cluster group; Alternatively, it is judged whether the current call is the first A8 link establishment request of the trunk group under the BSC of the current call.

Wherein, the established link is: the A8 link between the RAN internal BSC and the PCF;

In step a: the trunking call establishment request is the trunking call establishment request received by the BSC; the judgment is: the BSC judges whether the current call is the first trunking call establishment request of the trunking group under the BSC.

Wherein, when establishing the A8 link, the method further includes: the PCF and the PS establish a GMP link for the current call requesting to establish the A8 link.

Wherein, when establishing the A8 link, the method further includes:

a11. PCF judges whether the A8 link currently requested to be established is the first A8 link requested by the trunking group, if yes, PCF and PS establish a GMP link for the call currently requesting to establish an A8 link, and end the current process ; Otherwise execute step b11;

b11.PCF judges whether a GMP link has been established for the cluster group, if yes, adds the current call information to the information corresponding to the GMP link of the cluster group, and ends the current processing; otherwise, caches the current call information;

c11. The PCF judges whether the establishment of the current GMP link succeeds or fails, and if successful, adds the cached call information to the information of the successfully established GMP link; if it fails, releases the currently cached call.

In step c11, before releasing the currently cached call, the method further includes:

c111. Determine whether the number of GMP link establishment times has reached the preset threshold of link establishment times, if yes, release the remaining calls buffered, and end the current processing; otherwise, execute step c112.

c112. Extract a call from the cached call, set up a GMP link for the call, and record the number of GMP link establishments;

c113. Determine whether the establishment of the GMP link described in step c112 is successful or failed, if successful, add the cached remaining call information to the information of the successfully established GMP link; if failed, return to step c111.

Wherein, the method for judging whether the establishment of the GMP link is successful or failed is: PCF receives the GMP link establishment confirmation message returned by the PS within the specified time of the agreement, and the cause value carried in the message indicates that the link establishment is successful, Determine whether the currently established GMP link is successful or failed; or,

The PCF judges that the current GMP link establishment is successful based on receiving the GMP link establishment confirmation message from the PS within the time specified in the protocol, and the cause value carried in the message indicates that the link establishment is successful; according to the GMP link establishment confirmation message from the PS , and the cause value carried in the message indicates that the link establishment failed, and it is judged that the current GMP link establishment fails.

Wherein, the method for judging whether the establishment of the A8 link is successful or failed is: the BSC judges whether the currently established A8 link is successful or failed according to whether it receives the A8 link connection response returned by the PCF within the specified time of the agreement; or,

The BSC judges that the current A8 link is established successfully according to receiving the A8 link connection response from the PCF within the time specified in the agreement; and judges that the current A8 link fails to be established according to the A8 link release completion message from the PCF.

Wherein, the method for judging whether the establishment of the GMP link is successful or failed is: PCF receives the GMP link establishment confirmation message returned by the PS within the specified time of the agreement, and the cause value carried in the message indicates that the link establishment is successful, Determine whether the currently established GMP link is successful or failed; or,

The PCF judges that the current GMP link establishment is successful based on receiving the GMP link establishment confirmation message from the PS within the time specified in the protocol, and the cause value carried in the message indicates that the link establishment is successful; according to the GMP link establishment confirmation message from the PS , and the cause value carried in the message indicates that the link establishment failed, and it is judged that the current GMP link establishment fails.

As can be seen from the above scheme, the key of the present invention is: when the RAN establishes a shared link, if the current call is called for the first time by a non-trunk group, and it does not successfully establish a link for the trunk group, it will first The call is cached; then, when the cluster group successfully establishes a link, the call information cached by itself is added to the successfully established link information, and when the cluster group fails to establish a link, it is cached for itself The call establishes the link.

Therefore, the establishment method of the shared link in the digital trunking system provided by the present invention can avoid the repeated establishment of the shared link, and can make the trunking group call have an available link when sharing the link, so as to truly realize the same trunking Group calls share one service link, and the call loss rate is greatly reduced, which can effectively use system resources to achieve high-quality trunking services.

Description of drawings

Fig. 1 sets up a preferred embodiment processing flow schematic diagram of shared A8 link in the method of the present invention;

Fig. 2 is a schematic diagram of the processing flow of a preferred embodiment of the cached call setting up A8 link in Fig. 1;

Fig. 3 is a schematic diagram of the processing flow of a preferred embodiment of setting up a shared GMP link in the method of the present invention;

FIG. 4 is a schematic diagram of a processing flow of a preferred embodiment of the call establishment GMP link cached in FIG. 3 .

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

The method for establishing a shared link in a digital trunking system disclosed by the present invention can be applied to the establishment process of a shared A8 link and/or a shared GMP link, wherein the shared A8 link is established for calls of the same trunking group under the same BSC , to establish a shared GMP link for calls of the same cluster group under the same PCF. The A8 and/or GMP shared link establishment process of the method of the present invention will be described in detail below in conjunction with the accompanying drawings.

FIG. 1 is a schematic diagram of a processing flow of a preferred embodiment of establishing a shared A8 link in the method of the present invention. Among them, the A8 link is the service link between the BSC and the PCF, and the BSC mainly includes a call control unit (CC) and a resource management unit (RM); Send a call establishment request, send a resource application/release request to RM, and exchange messages with external entities. The cluster group ID and user information are stored in the CC. The RM is responsible for the allocation and management of business processing resources and A8 link resources, and saves Cluster group information. The A8 link establishment process shown in Figure 1 is jointly completed by the CC, RM, and PCF in the BSC, and the specific processing steps include:

Step 101: After receiving the cluster call setup request from the MS, the CC sends a Resource Apply Request to the RM. Here, the trunking call setup request may be a call origination request, a paging response, or a group call joining request, etc., and the trunking call setup request and the ResourceApply Request message include information such as a trunking group identifier and a user identifier.

Step 102: The RM reads the cluster group identifier in the Resource Apply Request message described in step 101, and judges whether the currently received cluster call setup request is the cluster group's No. A cluster call setup request, if yes, go to step 106; otherwise go to step 103.

Step 103: The RM judges whether the BSC has established an A8 link for the cluster group according to the cluster group information saved by the RM, and if yes, executes step 104; otherwise, executes step 105.

Here, it can be seen from the background technology that when establishing a shared link of trunking services, according to the trunking group information saved respectively, the BSC can know whether the current call is the first call establishment request for the trunking group, and whether the call has been established for the trunking group. If the group establishes an A8 link, the PCF can also know whether the current call is the first A8 link establishment request of the trunk group, and whether a GMP link has been established for the trunk group, so the specific judgment method will not be described in detail in this article.

Step 104: Add current call information in the A8 link information that the cluster group has established in itself, such as: add the user of the current call in the user information corresponding to the A8 link that the cluster group has established, so that Make the current call share this A8 link; and return a Resource ApplyConfirm message to the CC, which indicates that the CC does not need to establish a new A8 link for this cluster group, and ends the current processing.

Step 105: Buffer the current call information, and end the current processing. After receiving the link establishment result of the trunk group A8, the BSC will process the cached call information accordingly. Here, the cached call information includes: a cluster group ID, a user ID, and the like.

Wherein, in order to facilitate the management of call establishment, the call information is usually stored as a first-in first-out queue. There are many ways of caching, such as: opening up a static call information array for caching call information according to the number of users in the cluster group; or dynamically caching call information in the form of a linked list, etc., which call information caching is used specifically The manner is related to the realization of the system and the size of the cluster group, and is not limited by the present invention.

Step 106: The RM returns a Resource Apply Confirm message to the CC, through which the CC is instructed to establish an A8 link for the cluster group, so that the CC sends an A9-Setup-A8 message to the PCF to which the BSC is connected, requesting the establishment of an A8 link.

Here, the method for indicating whether the CC establishes an A8 link for the cluster group through the Resource Apply Confirm message may include: 1. Indicating by filling the message with an invalid or valid A8 link identifier (A8 Traffic ID) 2. Set a flag bit in the message to indicate, etc. There are many methods for specific indication, which are not limited by the present invention.

It can be seen from Figure 1 that when the BSC receives a group call, if the current call is the first call establishment request of the group under the BSC, the BSC sends an A8 link establishment request to the PCF, thereby starting to establish a link for the current group. Call establishment A8 link; if the current call is not the first call establishment request, and the BSC has successfully established an A8 link for the trunk group, the current call will share the established A8 link; if the current call is not The first call setup request, and the BSC has not successfully established the A8 link for the trunk group, the BSC caches the current call information until the result of the A8 link setup for the trunk group is known, and then the cached call to process.

FIG. 2 is a schematic diagram of the processing flow of a preferred embodiment of the call establishment A8 link cached in FIG. 1 . As shown in Figure 2, when the A8 link is established successfully, step 201 to step 205 are performed; when the A8 link fails to be established, step 201' to step 205' is performed.

When the A8 link is established successfully, the specific processing includes:

Steps 201 to 202: PCF returns A9-Connect-A8 message to CC after allocating resources for A8 link, and CC sends Resource Affirm Request to RM

Steps 203 to 204: After RM receives the ResourceAffirm Request message in step 202 within the specified time, it means that the current A8 link is successfully established, and then adds the cached cluster to the newly established A8 link information Group call information, such as user information, etc., so that the group call cached by the RM can share the A8 link. At the same time, the RM returns a Resource Affirm Confirm message to the CC to complete the A8 link establishment process.

Among them, when the BSC establishes the A8 link, the timing starts from sending the A8-Setup-A9 message to the PCF. If the A9-Connect-A8 message returned by the PCF is received within the time specified in the agreement, it means that the current A8 link is established successfully; otherwise It indicates that the A8 link fails to be established. Therefore, the BSC usually starts a timer when sending the A8-Setup-A9 message, and the timeout threshold of the timer is set to the time specified in the protocol. If the BSC receives the A9-Connect-A8 message before the timer expires, it will It can be determined that the establishment of the A8 link is successful; otherwise, it is determined that the establishment of the A8 link fails. The timer is usually started by the CC, and the CC sends a Resource Affirm Request message to the RM when judging that the A8 link is established successfully, and sends a Resource Release Request message to the RM when judging that the A8 link establishment fails.

Here, in order to determine whether the RM has successfully received the message from the CC, it also needs to start a timer when sending the Resource ApplyConfirm message. The duration of the timer is determined according to the internal implementation of the BSC. If the RM receives the Resource Affirm Request message, then it can be judged that the establishment of the A8 link is successful; otherwise, it is judged that the establishment of the A8 link fails, or when the Resource Release Request message is received, it is judged that the establishment of the A8 link fails.

In addition, it is also possible to only set a timer in the RM, and judge whether the A8 link is successfully established according to whether the Resource Affirm Request message from the CC is received before the timer expires. What kind of implementation mode of the timer is used specifically is not a problem solved by the present invention, and will not be described in detail here.

Step 205: The RM returns a Resource Apply Confirm message to the CC, through which it replies to the Resource Apply Request message previously sent by the CC, and instructs the CC not to establish an A8 link for the cluster group.

Wherein, the above-mentioned messages in step 201, step 202, and step 204 are messages related to the establishment of the first call of the cluster group, while the messages in steps 203 and 205 are for the processing of the current buffered call of the cluster group. Therefore, the Resource Apply Confirm message returned in step 205 should correspond to the current cached cluster group call one by one, and the RM will return the Resource Apply Confirm message for each cached call in turn.

When the A8 link fails to be established, the specific handling includes:

Step 201'～step 202': When the A8 link fails to be established, the PCF returns the A8 link release completion message to the CC, such as A9 releasing A8 to complete the A9-Release-A8 Complete message, which carries the current A8 link that failed to be established The information such as the A8 Traffic ID of the CC indicates that the current A8 link establishment of the CC fails. The CC sends a Resource Release Request message to the RM, which also carries information such as the cause value and the A8Traffic ID in the A9-Release-A8 Complete message described in step 201'.

Step 203': RM releases the A8 Traffic ID saved by itself according to the received Resource Release Request message, thereby releasing the A8 link resource, and returns a Resource Release Confirm message to CC to complete the failed A8 link establishment Road resource release.

Because, if RM does not receive the Resource Affirm Request message within the specified time, it can also judge that the current A8 link fails to be established. Therefore, the RM can start the timer when sending the Resource Apply Confirm message, and the timeout threshold of the timer is set to this The duration of the specified time, if the RM does not receive the Resource Affirm Request message before the timer expires, indicating that the current A8 link fails to be established, then the RM is directly triggered to perform the above step 203'.

Steps 204'～205': According to the cause value in the Resource Release Request message in step 202', the RM knows that this is the A8 link release request triggered by the A8 link establishment failure, so it extracts a call from the call information cached by itself , send a Resource ApplyConfirm message to the CC according to the call information, reply to the Resource Apply Request message previously sent by the CC for the call, and instruct the CC to start establishing the A8 link through the message, and then the CC sends the A9-Setup-A8 to the PCF, An A8 link is established for this call.

Then, as shown in Figure 2, the BSC decides to add the remaining call information cached by itself to the successfully established A8 link information or to extract the cached next call to set up the call based on the known result of the A8 link establishment as shown in Figure 2. A8 link, or release the remaining call information cached by itself.

Here, the A8 link establishment times threshold can be set in advance, and the initial value of the A8 link establishment times is set to zero. Before extracting the cached call each time, it is judged whether the number of A8 link establishment times for the cached call reaches the link establishment times Threshold, if yes, BSC will release the remaining call information in the cache, and end the trunking call establishment process; otherwise, extract a call from the cache, establish an A8 link for the call, and record the number of A8 link establishments. Like this, before above-mentioned step 204 ', further comprise: judge whether the A8 link setup number of times reaches the link setup times threshold set, if yes, release the call of current cache, end current processing; Otherwise execute step 204'.

In this embodiment, when the establishment of the A8 link for the first call of the trunk group fails, the BSC will continue to set up one or more A8 links for the cached call. Although this can minimize the call loss, it will make the trunk The call setup delay is too long and consumes a lot of system resources. The present invention also proposes another implementation mode: if the A8 link of the first call of the trunking group fails to be established, the BSC will release all the calls cached by itself, and notify the trunking group user to re-initiate the call establishment request, then the steps 204' and step 205' need not be executed. Adopting this method not only shortens the time delay of trunking call establishment, but also saves system resources. Here, when the RM releases the buffered call, the ResourceApply Confirm message returned by the RM to the CC carries the cause value indicating that the establishment of the A8 link failed, indicating that the CC does not need to establish the A8 link, and notifies the MS that the call establishment fails.

Wherein, the above-mentioned step 201', step 202', and step 203' are messages related to the first call establishment of the cluster group, and step 204' is the processing for the current buffered cluster group call . Therefore, when the RM is releasing the cached call, the ResourceApply Confirm message returned by step 204' is in one-to-one correspondence with the current cached cluster group call, and the number of the message is the same as the cached call quantity.

When the method of the present invention is applied to the establishment of the shared GMP link, its processing is basically the same as that of the shared A8 link. FIG. 3 is a schematic diagram of a processing flow of a preferred embodiment of establishing a shared GMP link in the method of the present invention. As shown in Figure 3, the specific steps include:

Step 301: After the PCF receives the A9-Setup-A8 message sent by the BSC, it judges whether the A9-Setup-A8 message is the first A8 link establishment request of the trunk group currently called, and if so, executes step 302; Otherwise, execute step 303 .

Step 302: The PCF sends a GMP link establishment request Link Setup Request message to the PS, thereby establishing a GMP link for the current call, and ending the current processing.

Step 303: The PCF judges whether it has established a GMP link for the cluster group according to the cluster group information stored by itself, and if yes, executes step 304; otherwise, executes step 305.

Step 304: Add current call information to the established GMP link information of the cluster group saved by itself, for example: add the A8 Traffic newly allocated by the PCF or BSC to the information of the established GMP link of the cluster group ID, etc., so that the A8 link requested to be established this time can share the GMP link, and the current processing ends.

Step 305: Buffer the current call information, and end the current processing. After learning the result of establishing the GMP link of the trunk group, the BSC will process the cached call information accordingly. Here, the cached call information includes information such as cluster group ID and A8 Traffic ID.

It can be seen from Figure 3 that when the PCF receives a cluster call, if the current call is the first A8 link establishment request of the cluster group under the PCF, the PCF sends a GMP link establishment request to the PS, thereby starting to establish a link for the current The A8 link requested to be established establishes a GMP link; if the current call is not the first A8 link establishment request, and the PCF has successfully established a GMP link for the cluster group, the A8 link currently requested to be established will share The established GMP link; if the current call is not the first A8 link establishment request, and the PCF has not successfully established a GMP link for the cluster group, the PCF caches the current call information until the cluster is known The group establishes the result of the GMP link, and then processes the buffered call.

When the processing described in FIG. 3 above is applied to trunking call establishment, all calls of the same trunking group under the same PCF can share the same GMP link. In the actual networking process of the trunking system, one PCF is usually connected to one or more BSCs. Therefore, according to the needs of system implementation, the PCF can also only establish a shared GMP link for calls of the same trunking group under the same BSC. The process of setting up this shared GMP link is basically the same as that shown in Figure 3, the difference being: the judgment in step 301 is that the PCF judges whether the A9-Setup-A8 The message is the first A8 link establishment request of the cluster group under the BSC.

FIG. 4 is a schematic diagram of a processing flow of a preferred embodiment of the call establishment GMP link cached in FIG. 3 . As shown in Figure 4, when the GMP link is established successfully, step 401 and step 402 are performed; when the GMP link fails to be established, step 401' and step 402' are performed.

When the GMP link is established successfully, the specific processing includes:

Step 401: After the PS allocates resources for the GMP link, the PS returns a GMP link establishment confirmation Link Setup Confirm message to the PCF. The message carries reason values such as link establishment success and other information, indicating that the current GMP link has been successfully established.

Step 402: After the PCF receives the Link SetupConfirm message described in step 401 within the time specified in the protocol, it determines that the current GMP link is established successfully, and then adds the group call that it has cached in the newly established GMP link information Information, such as: A8 Traffic ID, etc., so that the group call cached by the PCF can share the GMP link.

Here, the PCF starts a timer when sending a Link Setup Request, and the timeout threshold of the timer is set to the time specified in the above agreement. If a LinkSetup Confirm message is received before the timer expires, and the message carries a reason value such as link establishment Success and other information, it is determined that the cluster group has successfully established a GMP link, and the message triggers the PCF buffered A8 link requested by the cluster group to share the successfully established GMP link.

When the GMP link fails to be established, the specific handling includes:

Step 401': When the GMP link establishment fails, the PS returns a Link Setup Confirm message to the PCF, which carries reason values such as link establishment failure, and information such as the GMP link identification of the current establishment failure, thereby indicating the current GMP link of the PCF. Link establishment failed.

Step 402': According to the cause value in the Link Setup Confirm message described in step 401', the PCF knows that this is the GMP link establishment confirmation message triggered by the GMP link establishment failure, so it extracts a request for establishment from the call information cached by itself. A8 link information, send a Link Setup Request message to the PS according to the A8 link information, and establish a GMP link for the A8 link established by the request.

In addition, if the PCF does not receive the Link Setup Confirm message within the time specified in the protocol, it can also judge that the current GMP link establishment fails. Therefore, the PCF can start a timer when sending the Link Setup Request, and the timeout threshold of the timer is set to this If the PCF does not receive the LinkSetup Confirm message carrying information such as the success of the link establishment before the timer expires, indicating that the GMP link establishment fails, the PCF is directly triggered to perform step 402'.

Then, according to the result of the GMP link establishment as shown in Figure 4, the PCF decides whether to add the remaining call information cached by itself to the successfully established GMP link information, or to establish a GMP link for the next cached call, or to release The remaining calls cached by itself.

Here, the threshold for the number of times to establish a GMP link can be set in advance, and the initial value of the number of times for setting up a GMP link is zero. The number of times threshold, if yes, the PCF will release the remaining call information in the cache, and end the trunking call establishment process; otherwise, extract a call from the cache, establish a GMP link for the call, and record the number of GMP link establishment. Like this, before above-mentioned step 402 ', further comprise: judge whether the number of times of GMP link establishment reaches the link establishment number of times threshold that is set, if yes, release the call of current cache, end current processing; Otherwise execute step 402 '.

In this embodiment, when the first GMP link establishment of the cluster group fails, the PCF will continue to establish one or more GMP links for the cached call, which is the same as the establishment process of the above-mentioned A8 link. In order to shorten the cluster call The PCF can also release all the calls cached by itself when the first GMP link establishment of the trunk group fails, and return the call establishment failure message to the trunk group user through the BSC. To make the user re-initiate the call setup request, the step 402' does not need to be executed.

The above-mentioned Figures 1 to 4 respectively describe the establishment process of the shared A8 link and the shared GMP link in the method of the present invention, and the present invention can also be combined with the methods of Figures 1 to 4 to simultaneously establish a shared A8 link and a shared GMP link. That is to say: the CC in the BSC receives the cluster call establishment request, and starts to execute the processing described in Figure 1 and Figure 2, and after the PCF receives the A8 link establishment request, it also starts to execute the processing described in Figure 3 and Figure 4 , so that the RAN and the PS can establish a shared A8 link for the call of the same trunk group under the same BSC, and establish a shared GMP link for the A8 link of the same trunk group under the same PCF.

Here, since the shared A8 link is established for the users of the same cluster group under the same BSC, when the PCF receives the A8 link establishment request, it must not have established a GMP link for the cluster group under the BSC. Therefore, when The networking mode of the system is that one PCF corresponds to one BSC, or when a shared GMP link needs to be established for calls of the same cluster group under the same BSC, for a PCF, the A8 link and the GMP link form a one-to-one correspondence , it can be known that the currently received A8 link establishment request is the first A8 link establishment request of the cluster group under the BSC without judgment, and the cluster group has only this A8 link establishment request under the BSC Therefore, the PCF does not need to prepare the information of the A8 link established by the cache request, so that when establishing a shared GMP link, the process adopted is the same as that of the prior art, namely: step 301, step 303, step 304, and Step 305, step 402 and step 402' described in FIG. 4 do not need to be executed.

Because, the call that the problem solved by the present invention is aimed at: the non-first call that BSC/PCF receives when the A8/GMP link that cluster group does not have successful establishment at present; And for the cluster that BSC/PCF receives For the first call of the group and the non-first call received by the BSC/PCF when the trunking group currently has a successfully established A8/GMP link, the establishment of the shared A8/GMP link adopts the existing technology. Belong to the problem that the present invention relates to, so this paper will not go into detail.

In summary, the application of the method of the present invention can solve problems such as repeated establishment of shared links and call loss due to no available links that often occur in the prior art when establishing shared A8 and/or GMP links, and can be truly effective Use system resources to share links, ensure a reasonable success rate of trunking service call establishment, and improve service quality.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present invention are included in the protection scope of the present invention.

Claims (10)

1. A method for establishing a shared link in a digital trunking system, the method comprising:

a. after receiving the cluster call establishment request, the radio access network RAN judges whether the current call is the first call of the current call cluster group, if so, establishes a link for the current call, and ends the current processing; otherwise, executing the step b;

b. judging whether the cluster group establishes a link, if so, adding current call information in the information of the established link, and ending the current processing; otherwise, caching the current call;

c. judging whether the current link is successfully established or failed, if so, adding the cached call information into the information of the successfully established link; if the call fails, the currently cached call is released.

2. The method of claim 1, wherein before releasing the current buffered call in step c, the method further comprises:

c1. judging whether the link establishment frequency reaches a preset link establishment frequency threshold or not, if so, releasing the cached residual calls and ending the current processing; otherwise step c2 is performed.

c2. Extracting a call from the cached calls, establishing a link for the call, and recording the link establishment times;

c3. judging whether the link establishment is successful or failed in the step c2, and if the link establishment is successful, adding the cached remaining call information to the information of the link in the step c2 which is successfully established; if it fails, return to step c1.

3. The method according to claim 1 or 2, wherein the established link is: a group mapping protocol GMP link between a packet control function entity PCF in RAN and an external key, namely a service server PS;

in the step a:

the cluster call establishment request received by the RAN is an A8 link establishment request received by the PCF;

the judgment is as follows: the PCF judges whether the current call is a first A8 link establishment request of the cluster group; alternatively, it is determined whether the current call is the first A8 link establishment request of the cluster group under the base station controller BSC of the current call.

4. The method according to claim 1 or 2, wherein the established link is: an A8 link between the RAN internal base station controller BSC and the packet control function entity PCF;

in the step a:

the cluster call establishment request is a cluster call establishment request received by the BSC;

the judgment is as follows: the BSC judges whether the current call is a first cluster call establishment request of the cluster group under the BSC.

5. The method of claim 4, wherein when establishing the A8 link, the method further comprises: the PCF establishes a group mapping protocol, GMP, link with the push-to-talk service server PS for the call currently requesting establishment of the A8 link.

6. The method of claim 4, wherein when establishing the A8 link, the method further comprises:

PCF judges whether the A8 link requested to be established currently is the A8 link requested to be established for the first time in the cluster group, if so, the PCF and the PS establish a GMP link for the call of the A8 link requested to be established currently, and ends the current processing; otherwise, executing step b 11;

b11.PCF judges whether GMP link is established for the cluster group, if yes, current calling information is added in the information of GMP link corresponding to the cluster group, and current processing is finished; otherwise, caching the current call information;

the PCF judges whether the current GMP link establishment is successful or failed, if so, the cached calling information is added into the information of the successfully established GMP link; if the call fails, the currently cached call is released.

7. The method of claim 6, wherein before releasing the currently buffered call in step c11, the method further comprises:

c111. judging whether the GMP link establishment times reach a preset link establishment time threshold or not, if so, releasing the cached residual calls and ending the current processing; otherwise step c112 is performed.

c112. Extracting a call from the cached calls, establishing a GMP link for the call, and recording the establishment times of the GMP link;

c113. judging whether the GMP link establishment in step c112 is successful or unsuccessful, and if successful, adding the cached remaining call information to the information of the GMP link in step c112 that is successfully established; if not, return to step c111.

8. The method of claim 3, wherein the determining whether the GMP link establishment is successful or failed is: PCF judges whether the current established GMP link is successful or failed according to whether the GMP link establishment confirmation message returned by PS is received within the time specified by the protocol and the reason value carried by the message indicates that the link establishment is successful; or,

PCF receives GMP link establishment confirmation message from PS in the time specified by the protocol, and the reason value carried by the message indicates that the link establishment is successful, and judges that the current GMP link establishment is successful; and judging that the current GMP link establishment fails according to a GMP link establishment confirmation message from the PS and the reason value carried by the message indicates that the link establishment fails.

9. The method of claim 4, wherein the method for determining whether the A8 link establishment is successful or failed is as follows: the BSC judges whether the currently established A8 link is successful or failed according to whether an A8 link connection response returned by the PCF is received within the time specified by the protocol; or,

the BSC judges that the current A8 link is successfully established according to the A8 link connection response received from the PCF within the time specified by the protocol; and according to the A8 link release completion message from the PCF, judging that the current A8 link establishment fails.

10. The method of claim 6, wherein the determining whether the GMP link establishment is successful or failed is: PCF judges whether the current established GMP link is successful or failed according to whether the GMP link establishment confirmation message returned by PS is received within the time specified by the protocol and the reason value carried by the message indicates that the link establishment is successful; or,

PCF receives GMP link establishment confirmation message from PS in the time specified by the protocol, and the reason value carried by the message indicates that the link establishment is successful, and judges that the current GMP link establishment is successful; and judging that the current GMP link establishment fails according to a GMP link establishment confirmation message from the PS and the reason value carried by the message indicates that the link establishment fails.

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