CN100389633C - A Routing Area Update Method for Supporting Nodes Serving General Packet Radio Service - Google Patents

Abstract

The invention discloses a routing area update method, including: A. The mobile station sends a routing area update request to the SGSN, and the SGSN judges whether the routing area of the mobile station before the update belongs to the SGSN, and if yes, execute step B; otherwise, perform the SGSN Routing area update processing flow, and end this process; B.SGSN adds 1 to the number of routing area update requests in the SGSN, and judges whether there is subscription information of the mobile station in the SGSN, if yes, execute step C, otherwise, SGSN passes Send the logical link GPRS mobile management reset request message to the mobile station to notify the mobile station to initialize its own state variables, and then perform the follow-up process of routing area update in the SGSN, and end this process; C.SGSN notifies the mobile station of its routing area update The request has been accepted, and the number of successful routing area updates in the SGSN is increased by 1, and the mobile station notifies the SGSN of the completion of the routing area update.

Description

A Routing Area Update Method for Supporting Nodes Serving General Packet Radio Service

technical field

The invention relates to a GPRS routing area update technology, in particular to a SGSN routing area update method after a base station controller/packet control unit cutover.

Background technique

General Packet Radio Service (GPRS) is a communication system upgraded on the basis of Global System for Mobile Communications (GSM). It uses packet switching and uses statistical multiplexing and dynamic multiplexing technologies to enable each user in the GPRS network to Multiple wireless channels are selected, and one wireless channel can also be shared by multiple users.

In the GPRS network shown in Figure 1, the Serving GPRS Support Node (SGSN) is the main function node, which is connected with the Gateway GPRS Support Node (GGSN) through the Gn interface, and connected with the Home Location Register (HLR)/authentication through the Gr interface. Connected to the authority center (AUC), connected to the short message center (SMC) through the Gd interface, connected to the service control node (SCP) through the Ge interface, connected to the gateway mobile location center (GMLC) through the Lg interface, and connected to the mobile switching center through the Gs interface Center (MSC)/Visitor Location Register (VLR), connected with GPRS Support Node (GSN) in other public land mobile network (PLMN) through Gp interface, connected with GSM Base Station Subsystem (BSS) through Gb interface, and through The Ga interface is connected to a charging gateway (CG).

In the GPRS network, in order to ensure the mobility management between the mobile station (MS) and the SGSN, when the location and status of the MS change, or the periodic routing area update timer in the MS expires, the MS will initiate a routing area update. Only when the routing area is successfully updated, can the MS attach to the SGSN and access the GPRS network normally; otherwise, the MS will be disconnected from the network.

GPRS routing area update includes two types: intra-SGSN routing area update (Intra-SGSN RAU) and routing area update between SGSNs (Inter-SGSN RAU). Among them, Intra-SGSN RAU means that the two routing areas before and after the MS update belong to the same SGSN; and Inter-SGSN RAU means that the two routing areas before and after the MS update belong to different SGSNs. In order to measure the quality of Intra-SGSN RAU, the 3GPP protocol stipulates the performance index of Intra-SGSN RAU success rate, which means the ratio of the number of Intra-SGSN RAU successes to the number of Intra-SGSN RAU initiations. The high success rate of Intra-SGSN RAU indicates that it is easier for MS to access the GPRS network and attach to the SGSN, thereby obtaining high-quality network services.

Each SGSN working in the GPRS network has a limited working capacity, that is, the number of attached users and data traffic flow of each SGSN are limited. During the operation and maintenance of the GPRS live network, there is often a phenomenon of uneven distribution of sudden traffic, that is, some areas under the jurisdiction of the SGSN become hot spots with a large number of MS users for a period of time. The data and data service flow have approached or reached the system specifications, and are in a state of full load or even overload operation; at the same time, other SGSNs are in an idle state due to the small number of attached users. For example, the system specification capacity of SGSN1 and SGSN2 is 100,000 users, and the number of GPRS users attached to SGSN1 and SGSN2 is about 80,000 under normal circumstances. However, if some commercial activity or sports event is held in the area under the jurisdiction of SGSN1, a large number of GPRS users originally attached to SGSN2 will gather in the area belonging to SGSN1, causing the number of attached users on SGSN1 to reach or exceed 100,000 users At the same time, the number of attached users on SGSN2 is greatly reduced, making SGSN2 in a relatively idle state. The above situation leads to uneven traffic distribution on SGSN1 and SGSN2.

In order to use network resources more effectively and ensure service quality, when there is uneven SGSN traffic, it is necessary to adjust and redistribute the number of attached users on different SGSNs. Some base station controllers BSC or packet control units PCU are switched over to idle SGSNs. For the convenience of description below, "BSC/PCU" is used to represent "base station controller or packet control unit". As shown in Figure 2, SGSN1 governs BSC/PCU1 to BSC/PCUn, and SGSN2 governs BSC/PCUt to BSC/PCUt+m. Since there are many users attached to SGSN1 and few users attached to SGSN2, the traffic distribution is uneven. At this time, by switching BSC/PCUn from SGSN1 to SGSN2, the MS belonging to BSC/PCUn is attached to SGSN2, thereby reducing the load of SGSN1 and making full use of the resources of SGSN2. After the cutover is completed, the jurisdiction of SGSN1 changes from BSC/PCU1 to BSC/PCUn-1, and the jurisdiction of SGSN changes to BSC/PCUn and from BSC/PCUt to BSC/PCUt+m.

After the cutover of the BSC/PCU is completed, when the routing area of the cutover MS changes or its periodic routing area update timer times out, the above-mentioned MS will initiate a routing area update. As shown in Figure 3, the routing area update in the GPRS system includes the following steps:

Step 301. The MS sends a RAU Request message to the SGSN, requesting to initiate a routing area update.

In the RAU Request message sent by the MS, it carries the Packet Temporary Mobile Subscriber Identity (P-TMSI) and the old routing area identifier (OLD RAI) information element representing the information of the routing area where the MS was before updating.

Steps 302-303. Determine whether the routing area before the update belongs to the SGSN, and if so, execute the Intra-SGSN RAU processing flow; otherwise, the SGSN executes the Inter-SGSN RAU processing flow.

Here, the SGSN judges whether the routing area before the update belongs to the jurisdiction of the SGSN according to the OLD RAI information element carried in the received RAU Request message.

As shown in Figure 4, the Intra-SGSN RAU processing flow includes the following steps:

Step 401. The SGSN adds 1 to the number of Intra-SGSN RAU requests.

Since the SGSN has determined that the routing area where the MS is located before and after the routing area update belongs to its own jurisdiction, it adds 1 to the number of Intra-SGSN RAU requests at the beginning of the Intra-SGSN RAU process as the Intra-SGSN RAU success rate Calculates the denominator in the formula.

Step 402 . The SGSN judges whether it has the subscription information of the MS, and if yes, executes step 403 ; otherwise, executes step 406 .

According to the P-TMSI information element carried in the received RAU Request message, the SGSN inquires the subscription information of the MS on its own. If there is subscription information, it indicates that the MS can continue to access the SGSN; otherwise, the MS cannot access the SGSN. SGSN.

Steps 403-405. The SGSN sends a RAU Accept (RAU Accept) message to the MS, and adds 1 to the number of successful Intra-SGSN RAUs. After receiving the RAU Accept message, the MS sends a RAU Complete (RAU Complete) message to the SGSN.

When the SGSN finds the subscription information of the MS, it sends a RAU Accept message to the MS, indicating that it accepts the routing area update of the MS, and adds 1 to the number of successful Intra-SGSN RAUs; after receiving the RAU Accept message from the SGSN, the MS updates The MS stores the location and identity information, and returns the RAU Complete message to the SGSN; the SGSN knows that the MS's routing area update has been completed by receiving the RAU Complete message.

Steps 406-407. The SGSN sends a RAU Reject (RAU Reject) message to the MS, and then adds 1 to the number of Intra-SGSN RAU failures.

If the MS subscription information is not found, the SGSN sends a RAU Reject message to the MS, and indicates in the message that the reason for rejecting this routing area update is implicitly detached (ImplicitlyDetached). After receiving the RAU Reject message, the MS analyzes the reasons for the rejection. When the rejection reason is Implicitly Detached, the MS will re-initiate the attach process specified in the 3GPP protocol; at the same time, since the SGSN rejects the update request of the MS, the number of Intra-SGSN RAU failures will be increased by 1.

According to the provisions of the 3GPP TS 04.64 V8.7.0 protocol, the SGSN and the MS generally use unacknowledged information mode (UI) frames for signaling interaction and data transmission, and the user unacknowledged transmission status variable V is stored in both the MS and the SGSN. (U) and receive the value of the state variable V(UR). The value ranges of V(U) and V(UR) are both 0 to 511, and they are reversed within this range. V(U) records the sequence number of the next UI frame to be sent, and V(UR) records the sequence number of the next received UI frame. Regardless of whether it is an SGSN or an MS, every time a UI frame is sent, its own V(U) is incremented by 1; every time a UI frame is received, V(UR) is updated to N(U)+1, where N(U) is the UI frame The serial number of the UI frame, and the value of N(U) is equal to the V(U) value of the sender of the UI frame. In addition, for the MS, if the value of N(U) in the received UI frame is within the range of (V(UR)-32)≤N(U)<V(UR), and if the MS has received If a UI frame with the same value of N(U) has been received, the UI frame received this time is discarded.

The V(U) and V(UR) of the cutover MS in the new SGSN are both initial values of 0, but the V(U) and V(UR) saved by the MS are consistent with those before the cutover. If the N(U) carried in the UI frame delivered by the SGSN is within the range (V(UR)-32)≤N(U)<V(UR), the MS will directly discard the UI frame.

For example: MS was originally attached to SGSN1, and had interacted with SGSN1 in UI frames. Assuming that the MS has received 10 downlink UI frames with N(U) values from 0 to 9 sent by SGSN 1, the V(UR) value of the MS before the cutover is 10. After BSC/PCU cutover, the MS is cutover to SGSN2. At this time, the initial value of V(U) and V(UR) for the MS on SGSN2 is 0, and the value of N(U) in the UI frame sent by SGSN2 to the MS also starts from 0, while V(U) on the MS side and V(UR) remain the values before the cutover. After MS receives the downlink UI frame of SGSN2, it obtains N(U) in it. For the first 10 UI frames sent by SGSN2, its N(U) value ranges from 0 to 9, since the value of V(UR) in the MS is 10, the N(U) of these 10 UI frames The values are all within the range of (V(UR)-32)≤N(U)<V(UR); in addition, because the MS has received UI frames with N(U) values from 0 to 9 sent by SGSN1 , which is the same as the N(U) value of the first 10 frames delivered by SGSN2. Therefore, the MS directly discards the first 10 UI frames delivered by SGSN2.

In this case, if the first 10 UI frames sent by SGSN2 contain the RAU Reject message, and because the MS directly discards the above message, the MS considers that the network has not responded to the RAURequest message sent by it. According to the 3GPP agreement, the MS will repeat the Intra-SGSN RAU process judged as failed by SGSN2 for a period of time, so the number of Intra-SGSN RAU failure processes will be increased, which will seriously affect the success rate index and increase the system signaling burden.

In order to overcome the shortcomings of the above solutions, the Intra-SGSN RAU process shown in Figure 5 is usually used, which includes the following steps:

The description and processing method of steps 501-505 are exactly the same as the description and processing method of steps 401-405 in the method shown in FIG. 4 .

Step 506. The SGSN sends an Identity Request (Identity Request) message to the MS, requesting the MS's International Mobile Subscriber Identity (IMSI), and at the same time starts waiting for the Identity Response (IdentityResponse) message timer T3370.

Step 507. The SGSN judges whether the Identity Response message is received before the timer for the identity recognition response message expires, and if yes, returns to step 503; otherwise, performs step 508.

Step 508. The SGSN judges whether the maximum number of retransmissions of the Identity Request message has been reached, and if yes, execute step 509; otherwise, return to execute step 506.

In the GPRS system, network maintenance personnel can pre-set the maximum number of retransmissions of the Identity Request message of the SGSN, and each time the SGSN sends an Identity Request message, the number of times the message is sent will be increased by 1.

When the waiting timer for the Identity Response message has expired and the SGSN has not received the IdentityResponse message, in this step the SGSN decides whether to send the Identity Request message to the MS again according to the relationship between the number of times the Identity Request message has been sent and the maximum number of retransmissions. IdentityRequest message.

Steps 509-510. The SGSN sends a RAU Reject message to the MS, and then the SGSN adds 1 to the number of Intra-SGSN RAU failures.

When the number of retransmissions of the Identity Request message reaches the preset maximum number of retransmissions, the SGSN sends a RAU Reject message to the MS, and indicates in the message that the reason for rejecting this routing area update is Implicitly Detached; then the SGSN sends the Intra - SGSN RAU failure times increased by 1.

According to the protocol, each time the SGSN sends a downlink signaling, the N(U) carried in the UI frame is incremented by 1, and when the Intra-SGSN RAU is performed from step 501 to step 510, each time the Identity Request message is sent, N(U) plus 1. Therefore, by resending the Identity Request message, the value of N(U) can quickly jump out of the range of (V(UR)-32)≤N(U)<V(UR), so that the MS can process and respond to the SGSN normally The issued message reduces the number of failures of the Intra-SGSN RAU and improves the success rate of the process. However, this method still has the following shortcomings:

1. Since the SGSN resends the Identity Request message to the MS multiple times through the BSC/PCU when there is no MS subscription information in the SGSN, the signaling traffic burden of the SGSN and the BSC/PCU is heavy at the initial stage of cutover. Affect the performance of GPRS system;

2. Before the MS can normally process the messages sent by the SGSN, it still has to go through many failed Intra-SGSN RAU processes, which cannot fundamentally solve the problem of the low success rate of the Intra-SGSN RAU.

Contents of the invention

In view of this, the purpose of the present invention is to provide a routing area update method after BSC/PCU cutover, improve the success rate of Intra-SGSN RAU.

In order to achieve the above object, the invention provides a routing area update method after a BSC/PCU cutover, the method may further comprise the steps:

A. After the mobile station sends a routing area update request to the SGSN, the SGSN judges whether the routing area before the mobile station is updated belongs to the SGSN, if yes, then execute step B, otherwise, perform the routing area update process between SGSNs, and end The routing area update process;

B. SGSN adds 1 to the number of routing area update requests in the SGSN, and then judges whether there is subscription information of the mobile station in the SGSN, if yes, then execute step C, otherwise, the SGSN resets the mobile management by sending a logic link GPRS to the mobile station Request a message to notify the mobile station to initialize its own state variable, then perform the follow-up process of updating the routing area in the SGSN, and end the updating process of the routing area;

C. The SGSN notifies the mobile station that its routing area update request has been accepted, and adds 1 to the number of successful routing area updates in the SGSN, and the mobile station notifies the SGSN that the routing area update is complete after learning that the routing area update request is accepted.

The follow-up process of updating the routing area in the SGSN described in step B includes the following steps:

B11.SGSN notifies the mobile station that its routing area update request is rejected, and adds 1 to the number of routing area update failures in the SGSN;

B12. The mobile station notifies the SGSN that the initialization of its own state variables has been completed, and then the mobile station starts the attach procedure.

The follow-up process of updating the routing area in the SGSN described in step B includes the following steps:

B21.SGSN notifies the mobile station to report the identity information;

B22. The mobile station notifies the SGSN that the initialization of its own state variables has been completed, and sends its own identity information to the SGSN;

B23. The SGSN notifies the mobile station that its routing area update request has been accepted, and adds 1 to the number of successful routing area updates in the SGSN, and the mobile station notifies the SGSN of the completion of the routing area update after learning that the routing area update request is accepted.

The identity recognition switch is set in advance, then the follow-up process of the routing area update in the SGSN described in step B includes the following steps:

B31.SGSN judges whether the identification switch is turned on, if yes, execute step B32, otherwise, execute step B35;

B32.SGSN notifies the mobile station to report the identity information;

B33. The mobile station notifies the SGSN that the initialization of its own state variables has been completed, and sends its own identity information to the SGSN;

B34.SGSN notifies the mobile station that its routing area update request has been accepted, and adds 1 to the number of successful routing area updates in the SGSN. After the mobile station learns that the routing area update request is accepted, it notifies the SGSN that the routing area update is complete, and then ends the routing area update. process;

B35.SGSN notifies the mobile station that its routing area update request is rejected, and adds 1 to the number of routing area update failures in the SGSN;

B36. The mobile station notifies the SGSN that the initialization of its own state variables has been completed, and then the mobile station executes the attach procedure.

The state variables at least include: non-confirmed sending state variables and receiving state variables.

The method for the mobile station to notify the SGSN that the initialization of its own state variables has been completed is as follows: the mobile station sends a logic link GPRS mobile management reset confirmation message to the SGSN.

The method for the mobile station in step A to send a routing area update request to the SGSN is: the mobile station sends a routing area update request message to the SGSN;

The method for the SGSN in step C to notify the mobile station that its routing area update request has been accepted is: the SGSN sends a routing area update acceptance message to the mobile station;

The method for the mobile station to notify the SGSN of the completion of the update of the routing area in step C is: the mobile station sends a message of completion of the update of the routing area to the SGSN.

The method for the SGSN to notify the mobile station that its routing area update request is rejected is as follows: the SGSN sends a routing area update rejection message to the mobile station.

The method for the SGSN to notify the mobile station to report the identification information is as follows: the SGSN sends an identification request message to the mobile station;

The method for the mobile station to send its own identity information to the SGSN is: the mobile station sends an identity response message carrying its own identity information to the SGSN.

By applying the present invention, the GPRS system can rapidly increase the success rate of Intra-SGSNRAU after BSC/PCU cutover. Specifically, the present invention has the following beneficial effects:

1. Using the method of the present invention, in the Intra-SGSN RAU process after the BSC/PCU cutover, if there is no subscription information of the MS in the SGSN, then the SGSN sends the LLGMM-RESET-REQ message to the MS, requiring the MS to V(U) and V(UR) are set to an initial value of 0 to ensure that the MS will not discard SGSN messages, reduce the number of Intra-SGSN RAU failures, and increase the Intra-SGSN RAU success rate after BSC/PCU cutover, thereby improving the overall performance of the system;

2. The present invention can make the MS after the cutover successfully complete the Intra-SGSN RAU quickly and attach to the SGSN, avoiding the continuous retransmission of messages, effectively reducing the signaling flow burden of the GPRS system, and saving system resources ;

3. Since the MS after cutover in the present invention can successfully complete Intra-SGSNRAU in a short time, the unstable time of the system after BSC/PCU cutover is shortened, thereby improving the network service quality;

4. The present invention adds a few steps on the basis of the original Intra-SGSN RAU process, and the implementation is relatively simple.

Description of drawings

Figure 1 is a structural diagram of the GPRS network.

Fig. 2 is a schematic diagram of BSC/PCU cutover in the GPRS network.

Fig. 3 is a flow chart of routing area update after BSC/PCU cutover in GPRS network.

Fig. 4 is the flow chart of the Intra-SGSN RAU after the cutover of the existing BSC/PCU.

Figure 5 is a flow chart of the improved Intra-SGSN RAU after the cutover of the existing BSC/PCU.

Fig. 6 is a flow chart of Intra-SGSN RAU improved on the basis of Fig. 4 in Embodiment 1 of the present invention.

Fig. 7 is the flow chart of Intra-SGSN RAU improved on the basis of Fig. 5 in Embodiment 2 of the present invention

Fig. 8 is a flow chart of the Intra-SGSN RAU after the improved BSC/PCU cutover by combining Fig. 4 and Fig. 5 according to Embodiment 3 of the present invention.

Detailed ways

In order to make the purpose and technical solution of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and examples.

The present invention is a routing area update method after a BSC/PCU cutover, and its basic idea is: if there is no subscription information of the MS in the SGSN after the cutover, then introduce a logical link GPRS mobile management reset request (LLGMM- RESET-REQ) message and Logical Link Control Reset (LLC RESET) process of Logical Link GPRS Mobility Management Reset Confirmation (LLGMM-RESET-CNF) message, so that MS sets its own V(U) and V(UR) to The initial value is 0, so as to keep consistent with the SGSN again, so as to ensure that the MS can normally process the messages sent by the SGSN, and improve the success rate of Intra-SGSN RAU after cutover.

The present invention can respectively optimize the Intra-SGSNRAU process after the cutover of the existing BSC/PCU shown in Figure 4 or Figure 5, and can also combine the two Intra-SGSN RAU processes after the cutover of the existing BSC/PCU optimize.

Embodiment 1: Introduce the LLC RESET process in the simple Intra-SGSN RAU process after the cutover of the existing BSC/PCU.

As shown in Figure 6, this embodiment adds an LLC RESET process on the basis of Figure 4. At this time, the Intra-SGSN RAU process after BSC/PCU cutover includes the following steps:

The description and processing method of steps 601-605 are exactly the same as the description and processing method of steps 401-405 in the method shown in FIG. 4 .

Step 606. The SGSN sends an LLGMM-RESET-REQ message to the MS to negotiate parameters with the MS.

In this step, the SGSN prompts the MS to set V(U) and V(UR) to the initial value 0 by sending the LLGMM-RESET-REQ message.

Steps 607-610. The SGSN sends a RAU Reject message to the MS, and adds 1 to the number of Intra-SGSNRAU failures; the MS starts the attach process after sending the LLGMM-RESET-CNF message to the SGSN.

In this embodiment, the SGSN adopts the method of directly rejecting the update of the MS routing area, that is, sending the MS a RAU Reject message whose rejection reason is Implicitly Detached, and the SGSN adds 1 to the number of Intra-SGSN RAU failures.

For the MS, it first sends the LLGMM-RESET-CNF message to the SGSN, indicating that the MS side has completed the initialization of V(U) and V(UR); then, the MS starts the attachment procedure stipulated in the 3GPP protocol, that is, the MS sends a message to the SGSN After carrying the Attach Request (AttachRequest) message with the IMSI information element, the SGSN obtains the subscription information of the MS from the HLR according to the IMSI information element, and returns an Attach Accept (Attach Accept) message to the MS, and then the MS sends an Attach Complete ( Attach Complete) message, indicating that the MS has successfully attached to the SGSN.

Similarly, since both V(U) and V(UR) of the MS are cleared, the MS thinks that it has never received any UI frame; in addition, because the V(U) and V(UR) are all 0, then when the SGSN and the MS exchange UI frames for the first time, N(U) is also equal to 0, and at this time N(U) is not located in the agreement (V(UR)-32)≤N(U)<V( within the range of UR). Therefore, the MS can normally receive the message from the SGSN after initialization, and will not discard it directly.

After the above steps 607 to 610, although the MS's Intra-SGSN RAU failed this time, when the MS initiates a routing area update request again, since the MS's subscription information has been saved on the SGSN, the MS will be able to successfully complete the Intra-SGSN RAU. -SGSN RAU.

Embodiment 2: Introduce the LLC RESET process in the improved Intra-SGSN RAU process after the cutover of the existing BSC/PCU.

As shown in Figure 7, this embodiment adds an LLC RESET process on the basis of Figure 5. At this time, the Intra-SGSN RAU process after BSC/PCU cutover includes the following steps:

The description and processing method of steps 701-705 are exactly the same as the description and processing method of steps 401-405 in the method shown in FIG. 4 .

Step 706. The SGSN sends an LLGMM-RESET-REQ message to the MS to negotiate parameters with the MS.

In this step, the SGSN prompts the MS to set V(U) and V(UR) to the initial value 0 by sending the LLGMM-RESET-REQ message.

Steps 707-709. SGSN sends Identity Request message to MS, and then MS sends LLGMM-RESET-CNF message and Identity Response message to SGSN in turn, and returns to step 703.

Here, the SGSN first requests to obtain the IMSI of the MS by sending an Identity Request message to the MS; then, the MS sends the LLGMM-RESET-CNF message to the SGSN, indicating that the MS has completed the initialization of V(U) and V(UR); then , the MS sends an IdentityResponse message to the SGSN, and uploads the IMSI of the MS to the SGSN; after the SGSN obtains the subscription information of the MS from the HLR according to the IMSI information element, the SGSN returns to step 703, and continues the follow-up process of the Intra-SGSNRAU.

In this embodiment, when there is no MS subscription information in the SGSN, since both V(U) and V(UR) of the MS are cleared, the MS considers that it has never received any UI frame; in addition, because Both V(U) and V(UR) in the SGSN and MS are 0, then when the SGSN and the MS exchange messages for the first time, N(U) is also equal to 0, and at this time N(U) is not within the specified (V( UR)-32)≤N(U)<V(UR) range. Therefore, the MS can normally receive the message from the SGSN after initialization, and will not discard it directly.

Embodiment 3: Introduce the LLC RESET process after combining the two existing Intra-SGSN RAU processes after BSC/PCU cutover.

In this embodiment, an identity recognition switch is added to the SGSN, so that the SGSN can determine the manner of subsequent interaction with the MS by judging the state of the identity recognition switch.

As shown in Figure 8, the method for improving the Intra-SGSN RAU success rate after the BSC/PCU cutover in this embodiment includes the following steps:

The description and processing method of steps 801-805 are exactly the same as the description and processing method of steps 401-405 in the method shown in FIG. 4 .

Step 806. The SGSN sends an LLGMM-RESET-REQ message to the MS to negotiate parameters with the MS.

In this step, the SGSN prompts the MS to set V(U) and V(UR) to the initial value 0 by sending the LLGMM-RESET-REQ message.

Step 807. The SGSN judges whether the identity recognition switch is turned on, and if so, executes step 808; otherwise, executes step 811.

In this step, the SGSN determines the subsequent interaction with the MS by judging the state of the identity recognition switch, that is, if the identity recognition switch is turned on, the SGSN will continue to complete the routing area update process after requesting its IMSI from the MS; otherwise, the SGSN will adopt The way of rejecting the MS routing area update first, and then prompting the MS to start the attach procedure.

Steps 808-810. SGSN sends Identity Request message to MS, and then MS sends LLGMM-RESET-CNF message and Identity Response message to SGSN in turn, and returns to step 803.

Here, the SGSN first requests to obtain the IMSI of the MS by sending an Identity Request message to the MS; then, the MS sends the LLGMM-RESET-CNF message to the MS, indicating that the initialization of V(U) and V(UR) has been completed on the MS side; Then, the MS sends an IdentityResponse message to the SGSN, and uploads the IMSI of the MS to the SGSN; after the SGSN obtains the subscription information of the MS from the HLR according to the IMSI information element, the SGSN returns to step 803 and continues the follow-up process of the Intra-SGSNRAU.

Since both V(U) and V(UR) of MS are cleared, MS thinks that it has never received any UI frame; in addition, since V(U) and V(UR) in SGSN and MS are both 0 , then when the SGSN and the MS exchange messages for the first time, N(U) is also equal to 0. At this time, N(U) is not within the range (V(UR)-32)≤N(U)<V(UR) stipulated in the protocol Inside. Therefore, the MS can normally receive the message from the SGSN after initialization, and will not discard it directly.

Steps 811-814. The SGSN sends a RAU Reject message to the MS, and adds 1 to the number of Intra-SGSNRAU failures; the MS starts the attach process after sending the LLGMM-RESET-CNF message to the SGSN.

Since the identity recognition switch is not turned on, the SGSN adopts the method of directly rejecting the MS routing area update, that is, sending a RAU Reject message to the MS with the rejection reason as Implicitly Detached, and the SGSN adds 1 to the number of Intra-SGSN RAU failures.

For the MS, it first sends the LLGMM-RESET-CNF message to the SGSN, indicating that the MS side has completed the initialization of its own V(U) and V(UR); then, the MS starts the attach procedure stipulated in the 3GPP protocol, that is, the MS sends a message to the SGSN After sending the Attach Request message carrying the IMSI information element, the SGSN obtains the subscription information of the MS from the HLR according to the IMSI information element, and returns an Attach Accept message to the MS, and then the MS sends an Attach Complete message to the SGSN, indicating that the MS has succeeded Access to SGSN.

Similarly, since both V(U) and V(UR) of the MS are cleared, the MS thinks that it has never received any UI frame; in addition, because the V(U) and V(UR) are all 0, then when the SGSN and the MS exchange messages for the first time, N(U) is also equal to 0, and at this time N(U) is not located in the agreement (V(UR)-32)≤N(U)<V(UR ) within the range. Therefore, the MS can normally receive the message from the SGSN after initialization, and will not discard it directly.

After the above steps 811 to 814, although the MS's Intra-SGSN RAU failed this time, when the MS initiates a routing area update request again, the MS will be able to successfully complete the Intra-SGSN RAU because the MS's subscription information has been saved on the SGSN. -SGSN RAU.

It can be seen from the above process that when the identity recognition switch is turned on, the MS after the BSC/PCU cutover can successfully implement Intra-SGSN RAU in the new SGSN immediately; The MS can successfully attach to the SGSN only after a failed Intra-SGSN RAU procedure.

Using the method of the present invention, the MS can successfully attach to the SGSN in the first Intra-SGSN RAU process initiated after the cutover or in the attaching process immediately after the first Intra-SGSN RAU failure, which greatly reduces the Intra-SGSN RAU after the cutover The number of failures, thus effectively improving the Intra-SGSN RAU success rate after cutover.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the present invention. within the scope of protection.

Claims (9)

1. the routing region updating method after base station controller BSC or the packet control unit PCU cutover is characterized in that this method may further comprise the steps:

A. travelling carriage is after service universal grouping wireless business supporting node SGSN sends the Routing Area Update request, SGSN judges whether the route district before this travelling carriage upgrades belongs to this SGSN, if, execution in step B then, otherwise, carry out Routing Area Update handling process between the SGSN, and finish this Routing Area Update flow process;

B.SGSN adds 1 with the intra-SGSN routing area update request number of times, judge the CAMEL-Subscription-Information that whether has travelling carriage among this SGSN then, if, execution in step C then, otherwise, SGSN notifies the state variable initialization of travelling carriage with self by send logical links general packet radio service gprs mobile management reset request message to travelling carriage, then carries out the follow-up flow process of intra-SGSN routing area update, and finishes this Routing Area Update flow process;

Its Routing Area Update request of C.SGSN notice travelling carriage is accepted, and the intra-SGSN routing area update number of success is added 1, and travelling carriage knows that the Routing Area Update request is accepted back notice SGSN Routing Area Update and finishes.

2. the method for claim 1 is characterized in that, the follow-up flow process of the described intra-SGSN routing area update of step B may further comprise the steps:

Its Routing Area Update request of B11.SGSN notice travelling carriage is rejected, and the intra-SGSN routing area update frequency of failure is added 1;

B12. travelling carriage notice SGSN has finished the initialization of oneself state variable, and travelling carriage starts attachment flow then.

3. the method for claim 1 is characterized in that, the follow-up flow process of the described intra-SGSN routing area update of step B may further comprise the steps:

B21.SGSN notice travelling carriage reports identification information;

B22. travelling carriage notice SGSN has finished the initialization of oneself state variable, and sends the identification information of self to SGSN;

Its Routing Area Update request of B23.SGSN notice travelling carriage is accepted, and the intra-SGSN routing area update number of success is added 1, and travelling carriage knows that the Routing Area Update request is accepted back notice SGSN Routing Area Update and finishes.

4. the method for claim 1 is characterized in that, sets in advance the identification switch, and then the follow-up flow process of the described intra-SGSN routing area update of step B may further comprise the steps:

B31.SGSN judges whether the identification switch is opened, if, execution in step B32 then, otherwise, execution in step B35;

B32.SGSN notice travelling carriage reports identification information;

B33. travelling carriage notice SGSN has finished the initialization of oneself state variable, and sends the identification information of self to SGSN;

Its Routing Area Update request of B34.SGSN notice travelling carriage is accepted, and the intra-SGSN routing area update number of success is added 1, and travelling carriage knows that the Routing Area Update request is accepted back notice SGSN Routing Area Update and finishes, and finishes this Routing Area Update flow process then;

Its Routing Area Update request of B35.SGSN notice travelling carriage is rejected, and the intra-SGSN routing area update frequency of failure is added 1;

B36. travelling carriage notice SGSN has finished the initialization of oneself state variable, and travelling carriage is carried out attachment flow then.

5. as claim 1,2,3 or 4 described methods, it is characterized in that described state variable comprises at least: non-affirmation send state variable and accepting state variable.

6. as claim 2,3 or 4 described methods, it is characterized in that the initialized method that described travelling carriage notice SGSN has finished the oneself state variable is: travelling carriage sends the logical links GPRS mobile management acknowledge message that resets to SGSN.

7. the method for claim 1 is characterized in that, the described travelling carriage of steps A to the method that SGSN sends the Routing Area Update request is: travelling carriage sends the Routing Area Update request message to SGSN;

The received method of described SGSN notice its Routing Area Update request of travelling carriage of step C is: SGSN sends Routing Area Update to travelling carriage and accepts message;

The method that the described travelling carriage notice of step C SGSN Routing Area Update is finished is: travelling carriage sends Routing Area Update to SGSN and finishes message.

8. as claim 2 or 4 described methods, it is characterized in that the unaccepted method of described SGSN notice its Routing Area Update request of travelling carriage is: SGSN issues Routing Area Update Reject message to travelling carriage.

9. as claim 3 or 4 described methods, it is characterized in that described SGSN notice travelling carriage reports the method for identification information to be: SGSN sends the identification request message to travelling carriage;

Described travelling carriage to the method that SGSN sends self identification information is: travelling carriage sends the identification response message that carries self identification information to SGSN.

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