WO2006056125A1

WO2006056125A1 - A method for routing area updating after cutting over bsc/pcu

Info

Publication number: WO2006056125A1
Application number: PCT/CN2005/001945
Authority: WO
Inventors: Danming Zhou; Wei Gu
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2004-11-25
Filing date: 2005-11-17
Publication date: 2006-06-01
Also published as: CN100389633C; CN1780476A

Abstract

A method is for routing area updating after cutting over BSC/PDU. The method comprises the following steps: A. Mobile station sends a routing area updating request to SGSN, the SGSN judges whether the routing of the mobile station before updating belong to this SGSN, if yes, performing step B, otherwise, performing the routing area updating processing flow between SGSNs, and ending this routing area updating flow; B. the SGSN adds 1 to the routing area updating request time, judges whether there is subscription information for the mobile station in the SGSN, if yes, performing step C, otherwise, the SGSN notifies the mobile station to initialize its state variable, then performing the subsequent flow of routing area updating in the SGSN, and ending this routing area updating flow; C. the SGSN notifies the mobile station that its routing area updating request has been accepted, and add 1 to the successful routing area updating time in SGSN, the mobile station then notifies the SGSN that the routing area updating has been completed.

Description

Method for updating routing area of service general packet radio service support node

The present invention relates to a general packet radio service (GPRS) routing area update technology, and more particularly to a base station controller/packet control unit cut-off service GPRS support node (SGSN) routing area update method. Background of the invention

GPRS is a communication system that is upgraded based on the Global System for Mobile Communications (GSM). It uses packet switching and uses statistical multiplexing and dynamic multiplexing techniques to enable each user in the GPRS network to select multiple wireless channels. And a wireless channel can also be shared by multiple users.

In the GPRS network shown in Figure 1, the SGSN is the main functional node, which is connected to the Gateway GPRS Support Node (GGSN) through the Gn interface, and is connected to the Home Location Register (HLR)/Authentication Center (AUC) through the Gr interface. 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 accessed via the Gs interface and the Mobile Switching Center (MSC) The location register (VLR) is connected, connected to the GPRS support node (GSN) in other public land mobile network (PLMN) through the Gp interface, connected to the GSM base station subsystem (BSS) through the Gb interface, and through the Ga interface and the charging gateway. (CG) connected.

In the GPRS network, in order to ensure mobility management between the mobile station (MS) and the SGSN, when the location and status of the MS changes, or the periodic routing area update timer in the MS expires, the MS initiates a routing area update. Only when the routing area is updated successfully, the MS can attach to the SGSN to access the GPRS network normally; otherwise, the MS will exit The phenomenon of falling off the net.

The GPRS routing area update includes two types of routing area update (Intra-SGSN RAU) in the SGSN and Inter-SGSN RAU between the SGSN. The Intra-SGSN RAU refers to the fact that the two routing areas before and after the MS update belong to the same SGSN. The er-SGSN RAU refers to the two routing areas before and after the MS update belong to different SGSNs. In order to measure the quality of the Intra-SGSN RAU, the 3GPP protocol specifies the Intra-SGSN RAU success rate, which is the ratio of the number of Intra-SGSN RAU successes to the number of Intra-SGSN AU initiations. The high success rate of the Intra-SGSN RAU indicates that the MS is more likely to access the GPRS network and is more likely to be attached to the SGSN, thereby obtaining high quality network services.

Each SGSN operating in a GPRS network has limited working capabilities, that is, the number of attached users and data traffic of each SGSN is limited. During the operation and maintenance of the GPRS network, there is often a phenomenon in which the burst traffic is unevenly distributed. That is, some areas under the jurisdiction of the SGSN become hotspots with a large number of MS users for a period of time. The SGSN is attached to the user. The number and data traffic are close to or reach the system specifications, and are in a state of full load or even overload operation; at the same time, other SGSNs are idle due to the small number of attached users. For example, the system specification capacity of SGSN1 and SGSN2 is 100,000 users. Under normal circumstances, the number of GPRS users attached to SGSN1 and SGSN2 is about 80,000. However, if a certain commercial activity or sporting event is held in the area under the jurisdiction of SGSN1, a large number of GPRS users originally attached to SGSN2 are aggregated to the area belonging to SGSN1, resulting in the number of attached users on SGSN1 reaching or exceeding 100,000 users. At the same time, the number of attached users on SGSN2 is greatly reduced, which makes SGSN2 in a relatively idle state. This situation leads to uneven distribution of traffic on SGSN1 and SGSN2.

In order to use the network resources more effectively and guarantee the service shield, when the SGSN traffic volume is uneven, the number of attached users on different SGSNs needs to be adjusted and reallocated. The specific method is as follows: The SGSN in the overload state is under the jurisdiction of the SGSN. Part of the BSC/PCU cutover to On the idle SGSN. As shown in Figure 2, SGSN1 governs BSC PCU1 to BSC/PCUn, and SGSN2 governs BSC/PCUt to BSC/PCUt + m. Since SGSN1 has many attached users and SGSN2 has fewer attached users, the traffic distribution is uneven. By cutting the BSC/PCUn from the SGSN1 to the SGSN2, the MS belonging to the BSC/PCUn is attached to the SGSN2, thereby reducing the load on the SGSN1 and making full use of the resources of the SGSN2. After the cutover is completed, the scope governed by SGSN1 becomes BSC/PCU1 to BSC/PCUn-1, the jurisdiction of SGS becomes BSC/PCUn and the BSC/PCUt to BSC/PCUt+m.

After completing the cutover of the BSC/PCU, when the routing area of the cut MS is changed or its periodic routing area update timer expires, the 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 routing area update.

The RAU Request message sent by the MS carries the packet temporary mobile subscriber identity (P-TMSI) and the original routing area identifier (OLD RAI) cell representing the routing area information before the MS is updated - steps 302 ~ 303. Whether the former routing area belongs to the SGSN, and if yes, performs the Intra-SGSN RAU processing flow; otherwise, the SGSN performs the Inter-SGSN RAU processing flow.

Here, the SGSN determines whether the pre-updated routing area belongs to the jurisdiction of the SGSN according to the OLD RAI cell carried in the received RAU Request message.

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

Step 401. The SGSN increments the number of Intra-SGSN RAU requests by one.

Since the SGSN determines that the routing area where the MS is located before and after the routing area update belongs to its own jurisdiction, the number of times of the Mra-SGSN RAU request is increased by one at the beginning of the Intra-SGSN RAU process, as the success rate of the Intra-SGSN RAU. Calculate the denominator in the formula. Step 402. The SGS determines whether there is subscription information of the MS. If yes, step 403 is performed; otherwise, step 406 is performed.

The SGSN can query the subscription information of the MS according to the P-TMSI cell carried in the received RAU Request message. If the subscription information exists, the MS can continue to access the SGSN; otherwise, the MS cannot Access to the SGSNo

Steps 403 ~ 405. The SGSN sends a RAU Accept (RAU Accept) message to the MS, and adds 1 to the number of successes of the ra-SGSN RAU. After receiving the RAU accept message, the MS sends a RAU Complete (RAU Complete) message to the SGSN.

When the SGSN finds the MS subscription information, the RAU Accept message is sent to the MS, indicating that the routing area update of the MS is accepted, and the number of successes of the Intra-SGSN RAU is increased by one; after receiving the RAU Accept message of the SGSN, the MS updates. The location and identity information stored in the MS, and returning the RAU Complete message to the SGSN; the SGSN receives the RAU Complete message, and learns that the routing area update of the MS has been completed.

Steps 406 ~ 407. The SGSN sends a RAU Reject message to the MS, and then increments the number of ra-SGSN RAU failures by one.

In the case that 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 the current routing area update is Implicitly Detached. After receiving the RAU Reject message, the MS analyzes the reason for the rejection. When the reason for the rejection is Implicitly Detached, the MS re-initiates the attach procedure specified by the 3GPP protocol. At the same time, since the SGSN rejects the MS update request, the number of Intra-SGSN RAU failures is increased by one.

According to the 3GPP TS 04.64 V8.7.0 protocol, non-acknowledgment information mode (UI) frames are generally used for signaling interaction and data transmission between the SGSN and the MS, and user unacknowledged transmission state variables V are stored in both the MS and the SGSN. ( U ) and the value of the receive state variable V ( UR ). V ( U ) and V ( UR ) have values ranging from 0 to 511 and are turned within this range. Turn. V (U) records the serial number of the next transmitted UI frame, and V (UR) records the serial number of the next received UI frame. Regardless of whether it is SGSN or MS, each 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. Serial number, N (U) is equal to the sender of the UI frame

V (U) value. In addition, for the MS, if the N (U) value in the received UI frame is within the range of (V (UR) - 32 ) < N (U) <V (UR), and if the MS has received If the UI frame of the same N (U) value is used, the UI frame received this time is discarded.

The V (U) and V (UR) of the cut MS in the new SGSN are both initial 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 sent by the SGSN is in the range (V(UR) -32) < N (U) <V (UR), the MS will directly discard the UI frame.

For example: MS originally attached to SGSN1 and has interacted with SGSN1 over UI frames. Suppose the MS has received 10 downlink UI frames from 0 to 9 sent by SGSN1. The V (UR) of the MS before the cutover is 10. After the BSC/PCU is cut, the MS is cut to SGSN2. At this time, the V ( U ) and the MS on the SGSN2

V (UR) is the initial value of 0, and the N ( U ) value of the UI frame sent by SGSN2 to the MS also starts from 0, while the V (U) and V (UR) on the MS side remain the values before the cutover. . After receiving the downlink UI frame of SGSN2, the MS obtains N (U). For the first 10 UI frames delivered by SGSN2, the N(U) value is from 0 to 9. Since the value of V (UR) in the MS is 10, the N (U) of the 10 UI frames The value is in the range of (V (UR) -32) < N (U) <V (UR). In addition, since the MS has received the UI frame of N (U) value 0 to 9 delivered by SGSN1 The N(U) value of the first 10 frames delivered by SGSN2 is the same. Therefore, the MS discards the first 10 UI frames delivered by the SGSN2.

In this case, if the first 10 UI frames sent by the SGSN2 include the RAU Reject message, and the MS discards the message directly, the MS considers that the network does not respond to the message. The RAU Request message sent. According to the 3GPP protocol, the MS will repeatedly repeat the Intra-SGSN RAU process that is determined to be failed by the SGSN2 for a period of time, thus increasing the number of Intra-SGSN RAU failure processes, seriously affecting the success rate indicator, and increasing the system's Signaling burden.

In order to overcome the shortcomings of the foregoing solution, an Intra-SGSN RAU process as shown in FIG. 5 is generally adopted, and the process includes the following steps:

The descriptions and processing methods of steps 501 ~ 505 are exactly the same as the descriptions and processing methods of steps 401 ~ 405 in the method shown in FIG.

Step 506. The SGSN sends an Identity Request message (IMS) to the MS, requests the International Mobile Subscriber Identity (IMSI) of the MS, and starts a Waiting Identity Response (ID Response) message timer T3370.

Step 507. The SGSN determines whether to receive the Identity Response message before waiting for the identity recognition response message timer to expire. If yes, return to step 503; otherwise, go to step 508.

Step 508. The SGSN determines whether the maximum number of retransmissions of the Identity Request message is reached. If yes, step 509 is performed; otherwise, the process returns to step 506.

In the GPRS system, the network maintenance personnel can preset 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 is increased by one.

In the case that the waiting identity response message timer has expired and the SGSN has not received the Identity Response message, the SGSN determines, according to the relationship between the number of times the Identity Request message has been sent and the maximum number of retransmissions, to the MS. Send an Identity Request 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 an RAU Reject message to the MS, and indicates in the message that the reason for rejecting the update of the routing area is Implicitly Detached; then the SGSN will intra - SGSN RAU failures plus one.

According to the agreement, the SGSN sends one downlink signaling, and the N(U) carried in the UI frame is incremented by 1. When the Intra-SGSN RAU is performed in steps 501 to 510, the Identity Request message is sent every time, N ( U ) plus 1. Therefore, by retransmitting 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 delivered message reduces the number of failures of the ra-SGSNRAU and improves the success rate of the process. However, this method still has the following shortcomings:

1. In the case that the method does not have the MS subscription information in the SGSN, the SGSN retransmits the Identity Request message to the MS multiple times through the BSC/PCU. Therefore, in the initial stage of the cutover, the signaling traffic burden of the SGSN and the BSC/PCU is heavy. Affect the performance of the GPRS system;

2. Before the MS sends the message sent by the SGSN, the MS still has to go through multiple failed Intra-SGSN RAU procedures, which cannot solve the problem that the Intra-SGSN RAU has a low success rate. Summary of the invention

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

To achieve the above objective, the present invention provides a routing area update method after a BSC/PCU cutover, the method comprising the following steps:

A. After the mobile station sends a routing area update request to the SGSN, the SGSN determines whether the routing area before the mobile station update belongs to the SGSN, and if yes, performs step B, otherwise, Routing area update processing flow between SGSNs, and ending the routing area update process;

B. The SGSN adds 1 to the number of routing area update requests in the SGSN, and determines whether there is subscription information of the mobile station in the SGSN. If yes, step C is performed. Otherwise, the SGSN notifies the mobile station to initialize its own state variable, and then performs SGSN. The subsequent process of updating the inner routing area, and ending the routing area update process;

C. The SGSN notifies the mobile station that its routing area update request has been accepted, and increases the number of successful routing update times in the SGSN by one. After the mobile station learns that the routing area update request is accepted, it notifies the SGSN that the routing area update is complete.

The following process of the routing area update in the SGSN includes the following steps:

Bll. The SGSN notifies the mobile station that its routing area update request is rejected, and increases the number of failed routing update times in the SGSN by one;

B12. Mobile Station Notification The SGSN has completed initialization of its own state variables, and then the mobile station initiates the attach procedure.

Step B: The subsequent process of routing area update in the SGSN includes the following steps:

B21. SGS informs the mobile station of the identity information;

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

■ B23. The SGSN informs the mobile station that its routing area update request has been accepted, and increments the number of successful routing area updates in the SGSN by one. After the mobile station learns that the routing area update request is accepted, it notifies the SGSN that the routing area update is complete.

The subsequent process of updating the routing area in the SGSN in step B includes the following steps:

B31. The SGSN determines whether the identity switch is turned on, and if so, step B32 is performed, otherwise, step B35 is performed;

B32. The SGSN notifies the mobile station to report the identity information; B33. The mobile station notifies the SGSN that the initialization of its own state variable has been completed, and sends its own identity information to the SGSN;

B34. The SGSN notifies the mobile station that its routing area update request has been accepted, and increases the number of successful routing area update times in the SGSN by one. After the mobile station learns that the routing area update request is accepted, it notifies the SGSN that the routing area update is completed, and then ends the routing area update. Process;

B35. The SGSN notifies the mobile station that its routing area update request is rejected, and increases the number of failed routing update times in the SGSN by one;

B36. Mobile Station Notification The SGSN has completed the initialization of its own state variables and then moves the station to perform the attach procedure.

The state variables include at least: a non-acknowledgment transmission state variable and a reception state variable. Step B: The method for the SGSN to notify the mobile station to initialize the state variable of the mobile station is: The SGSN sends a logical link GPRS mobility management reset request message to the mobile station.

The mobile station notifies the SGSN that the initialization of its own state variable has been completed: the mobile station sends a logical link GPRS dynamic management reset acknowledgement message to the SGSN.

Step A: The mobile station sends a routing area update request to the SGSN by: the mobile station sends a routing area update request message to the SGSN;

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

Step C: The mobile station notifies the SGSN that the routing area update is completed: the mobile station sends a routing area update complete message to the SGSN.

The method for the SGSN to notify the mobile station that the routing area update request is rejected is: The SGSN' sends a routing area update reject message to the mobile station.

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

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

By applying the invention, the GPRS system can quickly improve the success rate of the Intra-SGSN RAU after the BSC/PCU is cut and connected. 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, the SGSN sends an LLGMM-RESET-REQ message to the MS, requesting the MS to V ( U ) and V ( U ) are set to an initial value of 0 to ensure that the MS does not discard the SGSN message, reduce the number of failures of the Intra-SGSN RAU, and improve the success rate of the ra-SGSN RAU after the BSC/PCU cutover. Improve the overall performance of the system;

2. The present invention enables the cut-and-route MS to successfully complete the Intra-SGSN RAU and attach it to the SGSN, thereby avoiding frequent retransmission of messages, effectively reducing the signaling traffic burden of the GPRS system, and saving System resources;

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

4. The present invention adds a few steps to the original ra-SGSN RAU process basis, which is relatively simple. BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows the structure of the GPRS network.

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

Figure 3 is a flow chart showing the routing area update after the BSC PCU is cut in the GPRS network.

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

FIG. 5 is a flow chart of an improved Mra-SGSN RAU after the existing BSC/PCU cutover. Figure 6 is a diagram showing an improved Mira-SGSN RAU in Figure 4 of Embodiment 1 of the present invention. flow chart.

7 is a flow chart of the Mra-SGSN RAU improved on the basis of FIG. 5 according to Embodiment 2 of the present invention.

FIG. 8 is a flow chart of the Mra-SGSN RAU after the BSC/PCU cutover is improved by combining FIG. 4 and FIG. 5 according to Embodiment 3 of the present invention. Mode for carrying out the invention

In order to make the objects and technical solutions of the present invention more comprehensible, the present invention will be further described in detail below with reference to the accompanying drawings.

The invention is a routing area update method after the BSC/PCU cutover, and the basic idea is: if the MS subscription information does not exist in the cut SGSN, the logical link GPRS mobility management reset request is introduced (LLGMM- RESET-REQ) Message and Logical Link GPRS Mobility Management Reset Acknowledgement (LLGMM-RESET-C F ) Message Logical Link Control Reset ( LLC RESET ) flow, causing MS to set its own V ( U ) and V ( UR ) The initial value is 0, so that the SGSN is consistent with the SGSN to ensure that the MS can process the message sent by the SGSN normally, and improve the success rate of the cut-off ra-SGSN AU.

The present invention can optimize the existing Intra-SGSN RAU. process after the existing BSC/PCU cutover shown in FIG. 4 or FIG. 5, and can also cut the ra-SGSN RAU process after the two existing BSC/PCU cutovers. Optimized after combining.

The method of the present invention is described below by three embodiments.

Embodiment 1: The IXC RESET procedure is introduced in the Intra-SGSN RAU procedure after a simple existing BSC/PCU cutover.

As shown in FIG. 6, this embodiment adds a LLC RESET flow to FIG. The ra-SGSN RAU process after the BSC/PCU cutover includes the following steps:

The description and processing method of steps 601-605 and steps 401-405 of the method shown in FIG. The description and processing methods are identical.

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

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

Step 607 - 610. The SGSN sends a RAU Reject message to the MS, and adds 1 to the number of failures of the Mra-SGSN RAU. After the MS sends the LLGMM-RESET-C P message to the SGSN, the attach procedure is started. In this embodiment, the SGSN adopts a method of directly rejecting the update of the MS routing area, that is, sending an RAU Reject message with the Implicitly Detached reason to the MS, and the SGSN adds 1 to the number of failures of the Mra-SGSNRAU.

For the MS, the LLGMM-RESET-CNF message is first sent to the SGS, indicating that the MS side has completed the initialization of V(U) and V(UR); then, the MS restarts the attach procedure specified by the 3GPP protocol, that is, the MS sends the SGS to the SGS. After carrying the Attach Request message of the IMSI cell, the SGSN obtains the subscription information of the MS from the HLR according to the IMSI cell, and returns an Attach Accept message to the MS, and then the MS sends the attach complete to the SGSN. (Attach Complete) message indicating that the MS has successfully attached to the SGSN.

Similarly, since both V (U) and V (U ) of the MS are cleared, the MS considers that it has never received any UI frames; in addition, due to V(U) and V in the SGSN and MS ( UR) is 0. When the SGSN interacts with the MS for the first time, the N (U) is also equal to 0. At this time, N (U) is not in the protocol (V (UR) -32) ≤ N (U) < Within the V (UR) range. Therefore, the MS can normally receive messages 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 is lost. If the MS initiates the routing area update request again, the MS will be able to successfully complete the Intra-SGSN RAU because the subscription information of the MS has been saved on the SGSN.

Embodiment 2: The IXC RESET procedure is introduced in the improved Intra-SGSN RAU procedure after the existing BSC/PCU cutover.

As shown in Fig. 7, this embodiment adds a LLC RESET flow to Fig. 5. The Intra-SGSN RAU process after the BSCPCU cutover at this time includes the following steps:

The descriptions and processing methods of steps 701 to 705 are exactly the same as those of step 401 405 in the method shown in FIG.

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

Steps 707 ~ 709. The SGSN sends an Identity Request message to the MS, and then the MS sends an LLGMM-RESET-CNF message and an Identity Response message to the 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 an LLGMM-RESET-CNF message to the SGSN, indicating that the MS has completed initialization of V (U) and V (UR); The MS sends an Identity Response message to the SGSN to upload 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 cell, the SGSN returns to step 703 to continue the subsequent process of the Intra-SGSN RAU.

In this embodiment, in the case that 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; When both V(U) and V(UH) in the SGSN and the MS are 0, when the SGSN and the MS first exchange messages, N (U) is also equal to 0, and N (U) is not at this time. Within the scope of (V ( UR ) - 32 ) < N ( U ) < V ( UR ) specified by the agreement. 'Therefore the MS can receive messages from the SGSN normally after initialization, instead of discarding it directly.

Embodiment 3: The Intra-SGSN RAU process after the cutover of two existing BSC/PCUs is combined and introduced into the LLC RESET process.

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

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

The descriptions and processing methods of steps 801 to 805 are exactly the same as the descriptions and processing methods of steps 401 to 40 ⁵ in the method shown in FIG.

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

In this step, the SGSN causes the MS to set V ( U ) and V ( UR ) to an initial value of 0 by sending a LLGMM-KESET-REQ message.

Step 807. The SGSN determines whether the identity switch is turned on. If yes, step 808 is performed; otherwise, step 811 is performed. In this step, the SGSN determines the manner of subsequent interaction with the MS by determining the status of the identity switch, that is, if the identity switch is turned on, the SGSN 釆 orientation MS requests its IMSI to continue to complete the routing area update process; otherwise, The SGSN takes the form of first rejecting the MS routing area update and then causing the MS to initiate the attach procedure.

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

Here, the SGSN first requests the acquisition by sending an Identity Request message to the MS. The IMSI of the MS; then, the MS sends an LLGMM-RESET-CNF message to the MS, indicating that the MS side has completed the initialization of V (U) and V (UR); then, the MS sends an Identity Response message to the SGSN again, the MS The MSI is uploaded to the SGSN. After the SGSN obtains the subscription information of the MS from the HLR according to the IMSI cell, the SGSN returns to step 803 to continue the subsequent process of the Intra-SGSN RAU.

Since both V (U) and V (UR) of the MS are cleared, the MS considers that it has never received any UI frames; in addition, since both V (U) and V (UR) in the SGSN and MS are 0 Then, when the SGSN interacts with the MS for the first time, N (U) is also equal to 0, and N (U) is not in the range of (V (UR) - 32 ) < N (U) <V (UR) specified by the protocol. Inside. Therefore, the MS can normally receive messages from the SGSN after initialization, instead of discarding it directly.

Steps 811 ~ 814. The SGSN sends a RAU Reject message to the MS, and adds 1 to the number of failures of the Mra-SGSN RAU. After the MS sends the LLGMM-RESET-CNF message to the SGS, the attach procedure is started.

Since the identity switch is not turned on, the SGSN adopts a method of directly rejecting the MS routing area update, that is, sending a RAU Reject message rejecting the reason to Implicitly Detached to the MS, and the SGSN increments the number of Intra-SGSN RAU failures by one.

For the MS, the LLGMM-RESET-CNF message is first sent to the SGSN, indicating that the MS side has completed the initialization of its own V (ϋ) and V (UR); then, the MS restarts the attach procedure specified by the 3GPP protocol, that is, the MS direction After the SGSN sends the Attach Request message carrying the MSI cell, the SGSN obtains the subscription information of the MS from the HLR according to the IMSI. The cell returns an Attach Accept message to the MS, and then the MS sends an Attach Complete message to the SGSN to indicate the MS. The SGSN has been successfully accessed.

Similarly, since both V (U) and V (UR) of the MS are cleared, the MS considers that it has never received any UI frames; in addition, due to V(U) and V(UR) in the SGSN and MS If both are 0, the N(U) is also equal to 0 when the SGSN interacts with the MS for the first time. At this time, N (U) is not in the protocol (V (UR) - 32) < N (U) <V (UR ) within the scope. Therefore, the MS can normally receive messages from the SGSN after initialization without directly discarding it.

After the above-mentioned step 811 to step 814, although the Intra-SGSN RAU of the current MS fails, when the MS initiates the routing area update request again, the MS will successfully complete the subscription information of the MS already stored on the SGSN. Intra-SGSN RAU.

It can be seen from the above process that, when the identity switch is turned on, the MS after the BSC/PCU cutover can successfully implement the Intra-SGSN RAU in the new SGSN; and in the case that the identity switch is turned off, the cutover is performed. The MS needs to go through a failed Intra-SGSN RAU process before it can successfully attach to the SGSN.

By using the method of the present invention, the MS can successfully attach to the SGSN in the attaching process immediately after the first Intra-SGSN RAU process initiated after the cutover or the first Intra-SGSN RAU failure, which greatly reduces the after-cutting of the Mra-SGSNRAU. The number of failures, which effectively improves the success rate of the Cutover Intra-SGSNRAU.

The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalents, improvements, etc., which are made within the spirit and principles of the present invention, should be included in the present invention. Within the scope of protection.

Claims

Claim

A method for updating a routing area after a BSC PCU cutover, characterized in that the method comprises the following steps:

A. After the mobile station sends a routing area update request to the SGSN, the SGSN determines whether the routing area before the mobile station update belongs to the SGSN, and if yes, performs step B, otherwise, performs a routing area update processing process between SGS, and ends. The routing area update process;

2. The method according to claim 1, wherein the subsequent process of updating the routing area in the SGSN in step B comprises the following steps:

The method according to claim 1, wherein the subsequent process of the routing area update in the SGSN includes the following steps:

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

B22. The mobile station notifies the SGSN that the initialization of its own state variable 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 increases the number of successful routing area update times in the SGSN by one. After the mobile station learns that the routing area update request is accepted, it notifies the SGSN that the routing area update is completed.

The method of claim 1, wherein the identification process is performed in advance, and the subsequent process of updating the routing area in the SGSN in step B comprises the following steps:

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

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

B36. Mobile Station Notification The SGSN has completed initialization of its own state variables, and then the mobile station performs the attach procedure.

The method according to any one of claims 1 to 4, characterized in that the state variables include at least: a non-acknowledgment transmission state variable and a reception state variable.

The method according to claim 1, wherein the step SG: the SGSN notifies the mobile station to initialize the state variable of the mobile station: the SGSN sends a logical link GPRS mobility management reset request message to the mobile station.

7. The method according to claim 2, 3 or 4, wherein the mobile station notifies the SGSN that the initialization of its own state variable has been completed: the mobile station sends a logical link GPRS mobility management reset acknowledgement message to the SGSN. .

The method according to claim 1, wherein the method for the mobile station 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 according to claim 2 or 4, wherein the SGSN notifies the mobile station that the routing area update request is rejected: the SGSN sends a routing area update reject message to the mobile station.

The method according to claim 3 or 4, wherein the method for the SGSN to notify the mobile station to report the identity identification information is: the SGSN sends an identity identification request message to the mobile station;

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