Management method of multicast users in mobile network

Multicast user management method in mobile network

Technical field

The invention relates to a method for managing multicast users in a mobile communication network.

The key to solving the above problems is to determine the topological distribution of group users in the network and determine the distribution path. On the Internet, the system regularly sends query packets and receives response messages to establish the topological relationship of multicast groups on the network. If the mobile network adopts a similar method, it can establish a multicast user distribution table by periodically querying the current status of the groups under each node. In this way, if the current location and status of each user is determined through paging, as the number of group users increases, the occupation of system network resources and wireless resources will increase sharply; if each node in the network queries the local database to determine the multicast path, it will follow With the increase of the number of nodes in the network, the query request broadcasted by the entire network will also rapidly increase the occupation of network resources. At the same time, each node has to process query requests, and its processing efficiency will decrease with the increase in the number of groups; for mobile users, it is difficult to immediately learn the changes in the distribution of current group users, and the distribution path of multicast data cannot be obtained. Adjust immediately accordingly. At the same time, due to the movement of users, it is not easy to determine the number of users under each network node. In this way, on the wireless interface side, it is impossible to determine whether the wireless interface adopts a point-to-multipoint channel or a point-to-point channel based on the change in the number of users under the current node.

It can be seen from the above that there is no better solution for how to apply the multicast service on the mobile network.

In order to achieve the above objective, a method for managing multicast users in a mobile network provided by the present invention includes: (1) Dividing data related to multicast services into multicast related record data and multicast routing data, where multicast Relevant record data is stored in the system for multicast service query, and the multicast routing data is divided into multiple levels and stored in the system to determine how to distribute the multicast data; (2) When a user joins a multicast group or more When the broadcast user exits the multicast group, adaptively modify the multi-level multicast routing data and multicast-related record data in the above-mentioned system;

(3) When a multicast user performs location registration and location update in the network, adaptively update the multi-level multicast routing data in the above system.

The method also includes: determining the topological structure of the mobile network so that each node in the network has a tree structure from the upper layer to the lower layer when performing multicast services, that is, making each General Packet Radio Support Protocol (GPRS) in the network The service support node (SGSN) may correspond to one or more radio access networks (RAN), and each RAN corresponds to only one SGSN.

In step (1), the multicast routing data is divided into multiple levels and stored in the system, which is to divide the multicast routing data into two levels. The first level is stored in the GGSN node and is used to record how the received multicast data is sent to The SGSN distributes multicast data; the second level is stored in the SGSN node, used to record how the received multicast data distributes the multicast data to the user cell, and as a reference for the multicast data distribution method.

The present invention also includes: establishing a GGSN multicast routing table in the GGSN node to record how the received multicast data distributes the multicast data to the SGSN. The table includes the following fields: multicast group group number, used for storage The multicast group that the GGSN can broadcast; the service node is used to store the destination SGSN where the GGSN can broadcast the multicast data; the update flag is used to mark whether the record has been updated.

The SGSN multicast routing table is established in the SGSN node to record how the received multicast data distributes the multicast data to the user cell and the reference of the multicast data distribution method. The table includes the following fields: multicast group group number , Used to store the multicast group that the SGSN can broadcast; gateway node, used to store the GGSN corresponding to the multicast group; cell, used to store the destination cell where the SGSN can broadcast multicast data;

Number of users, this field is optional, used to store the number of users of the multicast group in the destination cell; update flag, used to mark whether this record has been updated.

The present invention uses the multicast routing data to be divided into multiple levels and stored in the system to determine how to distribute the multicast data and to determine the cell where the multicast data is distributed, and when a user joins a multicast group or a multicast user exits the multicast group When broadcasting a group, adaptively modify the multicast record data and multi-level multicast routing data in the above-mentioned system. At the same time, when the multicast user performs location registration and location update in the network, the multi-level multi-level information in the above system is modified. The solution of adaptive update of broadcast routing data makes the present invention have the following advantages: 1. When the multicast user performs location registration or location update method, the multicast routing data in the system is adaptively updated without additional Occupy wireless resources and network resources. As the number of nodes or the number of groups increases, network resources and wireless resources will not be rapidly consumed, so the system network resources and wireless resources are less occupied.

2. When the multicast user location is updated, the multicast routing table data is updated in time. Therefore, the multicast routing table data can dynamically reflect the changes of the multicast group users. Compared with the method of regular query, it can ensure that the multicast routing table can reflect the topology changes of the multicast group users in a timely manner.

3. Since the number of users in each cell is stored in the multicast routing table, the wireless resource distribution method can be directly determined. Compared with the usual method of estimating the number of users in a cell through pre-paging, the problem of rapid increase in wireless resource consumption as the number of users increases will not occur.

4. Hierarchical storage of multicast data and an update method at the same time, so that any node failure in the network can automatically restore the data, thereby improving the reliability and security of the multicast routing table. At the same time, the hierarchical management of the routing table reduces the complexity of processing and managing the routing table of each node, and improves the processing efficiency of each node and the accuracy of the routing table.

5. Since the multicast routing table does not include other multicast related data of the multicast user, other multicast data is processed separately from the multicast routing table data, so that there is no need to query user data during routing distribution, which greatly improves the performance of each node. Processing efficiency. At the same time, it also avoids the problem of excessive waste of network resources by the traditional method of sharing queries.

Refer to Figures 2 and 3 in the mobile network to which the present invention is applied. The network shown in the figure usually includes a GPRS Gateway Support Node (GGSN) 2, a GPRS Service Support Node (SGSN) 3, a Radio Access Network (RAN) 4, and a mobile station. 5; From the SGSN side, each specific multicast group can be considered to be always associated with a specific GGSN group. In practice, the GGSN node 2 receives the multicast data through the external network 1 and distributes it to each SGSN node 3 in the mobile network, and then the SGSN node 3 sends the multicast data to the mobile station 5 through the RAN node 4. In order to prevent the SGSN from receiving the same multicast data from multiple GGSNs and wasting network resources, various optimization strategies can be adopted to ensure that for a specific multicast group, a certain SGSN is only associated with a specific GGSN. Refer to Figure 2 for the topology of the associated mobile network. For Figure 3, due to the many-to-many relationship between SGSN and RAN, in practice, for multicast data, the same group of multicast data may come from different SGSN nodes, resulting in RAN receiving from multiple different nodes. The same data of the node. If the network topology is not simplified, and the above-mentioned methods are used to manage the multicast data and routing, it will inevitably cause waste of system resources and confusion in management. For this reason, the relationship between the nodes in Figure 3 must be improved logically. Through a certain strategy, the many-to-many relationship between SGSN and RAN is simplified to a one-to-many relationship. Refer to Figure 2. By determining the topological structure of the mobile network, each node in the network has a tree structure from the upper layer to the lower layer when performing multicast services, that is, each SGSN node in the network can correspond to one or more RANs. Each RAN node corresponds to only one SGSN node. Taking Figure 3 as an example, it is necessary to resolve the mesh topology relationship into a tree topology relationship.

For example, for normal point-to-point data transmission, users registered in the E-node RAN can usually transmit through the SGSN of the B node, the SGSN of the C node, or the SGSN of the D node according to their initial registration node. For multicast data, users registered in the RAN of the E node can only transmit through the SGSN of the B node. Therefore, through this method, each RAN node can be uniquely associated with an SGSN node, thereby transforming the mesh topology relationship in FIG. 3 into the tree topology relationship as in FIG. 1. In this way, the user registered in the RAN of the E node may correspond to two nodes: the SGSN of the C node and the SGSN of the B node, where the SGSN of the C node is used to process normal services, and the SGSN of the B node is used to process multicast services. At this time, the SGSN used for multicast transmission can be called a multicast SGSN, and the SGSN used for normal data transmission can be called a registered SGSN to distinguish between the two.

Fig. 1 is a flowchart of an embodiment of the method of the present invention. According to Figure 1, the present invention divides the data related to the multicast service into two types in the first step: one is the user's multicast related record data, which records the related information of the user joining the multicast group. The data is not used for multicast data distribution, but only for multicast service query. By querying the data, the distribution of specific users in the group can be determined. This data is recorded separately in the HLR and SGSN to avoid repeated queries to the HLR, which will cause the HLR to be overburdened. The second is multicast routing data. It is used to determine how each node distributes data on the network topology. The multicast routing data is used to determine the distribution route of the data, and the hierarchical storage method is adopted in the present invention. The basic idea of managing multicast routing data is to use the characteristics of the mobile network. Each user needs to do location registration and location updates when location changes occur to maintain and update the multicast routing data. Multicast routing data only cares about the topological distribution of group users on the network, and does not care about the situation of each specific user in the group.

It can be seen from the above that the multicast related data and the multicast routing data are complementary to each other, which can determine the topological distribution of the group in the network node, and also determine the distribution of specific users in the network node. Thereby ensuring the efficiency and effectiveness of multicast data distribution. Since the user's multicast-related record data management is relatively simple in practice, the present invention mainly relates to how to manage the multicast routing data.

Specifically, in order to better manage the multicast routing data, the multicast routing data is divided into two levels. The first level is stored in the GGSN node and used to record how the received multicast data distributes the multicast data to the SGSN. The second level is stored in the SGSN node and is used to record how the received multicast data distributes the multicast data to the user cell. The multicast data recorded in the SGSN can also include the number of users in each cell, so that based on the number of users, the system can determine that when sending multicast messages in each corresponding cell, the air interface that should be used is point-to-point. Multipoint channels are still point-to-point channels.

To this end, a GGSN multicast routing table needs to be established in the GGSN node to record how the received multicast data distributes the multicast data to the SGSN. The table includes the following fields: multicast group group number, used to store the GGSN Multicast group that can be broadcast; service node, used to store the destination SGSN that the GGSN can broadcast multicast data.

Update mark: used to mark whether this record has been updated.

The SGSN multicast routing table is established in the SGSN node to record how the received multicast data distributes the multicast data to the user cell. The table includes the following fields: multicast group group number, used to store the SGSN can broadcast Multicast group; gateway node: used to store the GGSN corresponding to the multicast group; cell, used to store the destination cell where the SGSN can broadcast multicast data; the number of users, used to store the destination cell where the multicast data can be broadcast The number of users; update flag: used to mark whether it has been updated.

For example, two users joining the group number 100 are located in the SGSN1 and SGSN2 areas, and the corresponding GGSN of the group 100 in the SGSN area is determined to be GGSN1 according to the optimization strategy, then the following GGSN multicast routing table is established on GGSN1:

The following SGSN multicast routing table will be added on SGSN1:

In this way, GGSN1 queries its own GGSN multicast routing table for the received multicast data with group number 100, and learns that users with multicast group number 100 are only distributed on SGSN1 and SGSN2, then GGSN1 will multicast the data Distributed to SGSN1 and SGSN2. SGSN1 receives the multicast data with the group number of 100. SGSN1 queries its own multicast routing table and determines to send the multicast data to cells C1 and C2. At the same time, it can also determine the airborne data used according to the number of users in the cell. Interface delivery method. If the SGSN finds that the number of users in the relevant cell is large, it can notify the RAN to use the group number as an identifier to allocate a point-to-multipoint service channel. If the SGSN finds that the number of users in the relevant cell is small, it searches for users in the cell and allocates an independent point-to-point service channel for each user. In this way, users distributed in cells C1 and C2 can receive the multicast message.

It should be noted that the SGSN multicast routing table does not need to include the user's individual digit field, which can simplify the complexity of the data management of the multicast routing table. At this time, for the SGSN, it is just unable to determine the data distribution method adopted by the wireless interface, and has no effect on the multicast data distribution on the network side. At this time, the SGSN delivers the multicast data to the relevant cell, and the cell decides the wireless The method of distributing multicast data on the interface.

In step 2, when it is determined whether any user joins the multicast group or the multicast user exits the multicast group, if so, in step 3, the multi-level multicast routing data in the above system is adaptively modified. That is, each SGSN node first determines whether the routing table entry related to the user exists in the process of establishing the above-mentioned routing table. If it does not exist, the entry must be added to the routing table, and at the same time, it is determined whether it is necessary to notify the GGSN to modify the multicast routing data table ; If it already exists, make an updated mark; if the number of users in each cell needs to be counted in the SGSN routing table, the user number data entry in the SGSN multicast routing table needs to be modified. Through the above method, each routing table can be established and maintained in each node of the SGSN and GGSN one by one.

When a user exits a multicast group, if the number of users is not recorded in the SGSN multicast routing table, neither the SGSN multicast routing table nor the GGSN multicast routing table will be modified, and only the user multicast related record data on the SGSN will be modified. , And notify the HLR to modify the users multicast-related record data. For the possible modification of the multicast routing table data of each node, the modification is completed through the subsequent location registration step. If the SGSN multicast routing table contains a number of users, in addition to the above operations, it is also necessary to determine whether to delete related entries and notify the GGSN node of the GGSN multicast routing according to the number of users in the updated SGSN multicast routing table The table is updated.

If the user is detached, and the user is a group user, a process similar to that of the user exiting the group can be adopted.

In this way, when the GGSN receives a group of multicast data from the external network, the GGSN queries the GGSN multicast routing table of the first layer, and forwards the multicast data to the corresponding SGSN. After the relevant SGSN receives the multicast data, it queries the second-layer SGSN multicast routing table to determine the corresponding group distribution, and then delivers it to the corresponding location cell to complete the multicast data delivery. If there is a record of the number of users in each cell in the SGSN multicast routing table of the second layer, the SGSN can also determine the wireless interface distribution mode of the multicast data. If the number of users in the cell is large, the SGSN can correlate the group identification to notify the RAN to establish a point-to-multipoint channel. If the number of users in the cell is small, the SGSN can use the user identification to notify the RAN to establish a point-to-point channel.

In this step, the process of the user joining the multicast group may include the following steps, refer to FIG. 4.

First, in step 11, the user sends a request to join the multicast group including the number of the multicast group to be added to the SGSN; then in step 12, the SGSN uniquely parses out a corresponding GGSN according to the multicast group number and optimization strategy , And forward the users joining request to the GGSN; in step 13, the GGSN executes the relevant process according to the users request to determine whether the user can join the multicast group. If the GGSN determines that the user can join the multicast group according to the relevant processing process For example, query the multicast records of HLR users to determine whether the user has the relevant authority, and then return a multicast group activation instruction to the SGSN; in step 14, the SGSN receives the multicast activation instruction, and notifies the RAN to join the multicast group. Related operations, such as sending multicast parameters, etc., and feedback the operation results to the SGSN. The SGSN will modify the corresponding user multicast record data and the SGSN multicast routing table according to the current location of the user to reflect that the user has joined the multicast group and the topological distribution of the group users in the area under the jurisdiction of the SGSN ; In step 15, the SGSN feeds back a multicast activation response message to the GGSN, and the GGSN modifies the GGSN multicast routing table according to the message; finally in step 16, the SGSN notifies the HLR that the user has joined the group, and the HLR modifies the user The multicast record data of to reflect that the user has joined the relevant group.

When it is determined in step 2 that no user has joined the multicast group or the multicast user has exited the multicast group, step 4 is performed.

In step 4, it is judged whether the multicast user is performing location registration and location update in the network. If so, in step 5, the multi-level multicast routing data in the above system is adaptively updated, otherwise it ends.

Since the status of the user in the network changes dynamically, for example, the user is shut down, especially abnormally. At this time, because there is no normal signaling interaction between the user and the network, if the multicast routing data cannot reflect the change of the user's status, then It may lead to a great waste of network resources. Therefore, the multicast routing table in the system must be able to reflect the dynamic changes of the group users in each node and be automatically adjusted at the same time.

The adaptive update of the multi-level multicast routing data in the system described in step 5 can be performed during the location registration of the user terminal. Usually, the network node can confirm that the terminal is still within the jurisdiction of the node after receiving the location registration information of the terminal, and at the same time, it can also confirm whether the user's current location record is correct. If the network detects that the terminal has not registered the location for several consecutive cycles, it can confirm that the user cannot be connected temporarily due to various reasons.

Because when a user joins a multicast group, the related record data of the user's multicast group has been added to the SGSN and HLR nodes. Therefore, each time a user performs location registration, the SGSN can query the local database to learn the multicast group that the user currently joins according to the user ID. Then the SGSN updates the SGSN multicast routing table according to the multicast group that the user has joined. The steps are as follows: (21) If there is no entry corresponding to the group user in the SGSN multicast routing table, this may be due to The users initial attachment, SGSN failure or other causes of data inconsistency, therefore need to add this entry, and determine whether it is necessary to notify the GGSN to update the related GGSN multicast routing table. If it is judged that there is no routing information related to the multicast group on the SGSN, an update notification needs to be sent to the GGSN; (22) If the number of users is included in the SGSN multicast routing table, the SGSN can also use the location registration process of the terminal to trigger and make certain statistics. The number of users in each cell in the node within the time, and according to the statistical value, the SGSN multicast routing table is revised to accurately reflect the number of group users in each cell at present; (23) If within a long enough time, SGSN multicast routing If the relevant entries in the table have not been updated, it can be considered that the group users of the cell cannot be connected due to various reasons or the data is inconsistent. At this time, the SGSN multicast group routing table deletes the entry and determines whether it needs to be notified. The GGSN node updates the relevant multicast routing table if it needs to be updated, and if it needs to be updated, it sends an update notification.

In addition, to prevent the GGSN from inconsistent with the SGSN routing table data. The SGSN can report the group existence information to the relevant GGSN periodically or when the GGSN node restarts according to its stored multicast routing group information. If the GGSN does not receive the information within a certain period of time, it can be considered that the relevant routing table entry is invalid and can be deleted. If the group existence information received by the GGSN is new data in the GGSN, it can be considered that the data of the GGSN needs to be updated to reflect the topological distribution of the group and prevent inconsistencies between the multicast data tables.

The adaptive update of the multi-level multicast routing data in the system in step 5 also includes the process when the user terminal performs location update. For example, at a certain moment the SGSN needs to distribute multicast data to a certain cell, and at the next moment because all users of this cell move out of the cell, the SGSN should not distribute multicast data to this cell. Therefore, the maintained multicast group routing table must also reflect the dynamic changes of the user's location.

When the location switch of the multicast user occurs, the following steps can be referred to for adaptive update of the multicast routing data: (31) Determine whether the location update of the multicast user is a location switch within the SGSN. If so, the SGSN only needs to be based on the user. Update the SGSN multicast group routing table with the reported location and its multicast related record data. If the number of users needs to be counted in the table, the SGSN will update the corresponding user number table entries according to the user location update situation at this time.

(32) If the location is updated as a location switch between SGSNs, the terminal will report its original temporary mobile user identity code and obtain the original SGSN identity to the new SGSN. The new SGSN can obtain all the user data from the original SGSN according to these parameters. , Including the users current record data related to the multicast service; at the same time, the original SGSN updates the multicast routing table. If the number of users is recorded in the table, it must also determine whether to delete the relevant entries and notify the original according to the number of users after the update. The GGSN node updates the GGSN multicast routing table; the new SGSN determines whether it needs to update its SGSN multicast routing table according to the group number the user joins, the cell where the user is currently located, and whether the group the user joins supports roaming. If the group that the user joins supports roaming services, the SGSN must update the multicast routing table according to the current status of the SGSN multicast routing table in addition to updating the multicast routing table of the corresponding GGSN. It includes the following steps:

(41) If the user is in an idle state, the new SGSN selects a GGSN according to the current optimization strategy, and then the SGSN judges whether the entry in its SGSN multicast routing table already exists, and at the same time, it needs to judge whether to notify the selected GGSN to update the corresponding GGSN multicast routing table; (42) If the user is connected and the group that the user joins does not need to support continuous transmission, the new SGSN selects a GGSN according to the current optimization strategy, and then the SGSN judges its own SGSN multicast Whether the entry in the routing table already exists, and at the same time, it is necessary to determine whether to notify the selected GGSN to update the corresponding GGSN multicast routing table; (43) If the user is connected and the group that the user joins needs to support continuous transmission, then The new SGSN determines whether it needs to notify the original GGSN to update its GGSN multicast routing table to add the entry based on whether the entry already exists. If notification is required, it temporarily establishes a data channel between the original GGSN and the new SGSN to enable multicast data It can be continuously transmitted. When the multicast data transmission is completed, the new SGSN needs to notify the original GGSN multicast routing data table to delete the temporary entry, and then the new SGSN selects a GGSN according to the current optimization strategy, and then the SGSN judges its own SGSN multicast Whether the entry in the routing table already exists, and at the same time, it is necessary to determine whether to notify the selected GGSN to update the corresponding GGSN multicast routing table.

By adopting the above steps, it can be ensured that the above-mentioned multi-level multicast group routing table can be automatically adjusted, thereby ensuring that the content of each multicast routing table is consistent with the group user topology distribution at the moment, and the multicast group management is achieved. The purpose is to avoid data inconsistency and resource waste in multicast data distribution that may be caused by various abnormal conditions of users.

Finally, it needs to be explained: 1. The location registration of the user terminal according to the present invention includes two cases of initial attachment and regular location registration.

2. Since the structure of the circuit domain (CS) is basically the same as the structure of the packet (PS) domain, the multicast in the circuit domain can also use the method described in the present invention.