CN101583123B

CN101583123B - Handover method among packet switching domain systems, device and system

Info

Publication number: CN101583123B
Application number: CN2009100872979A
Authority: CN
Inventors: 马新友; 刘建军
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2009-06-15
Filing date: 2009-06-15
Publication date: 2011-06-08
Anticipated expiration: 2029-06-15
Also published as: WO2010145490A1; CN101583123A

Abstract

The embodiment of the invention relates to a handover method among packet switching domain systems, a device and a system. The method comprises: a BSS receives a handover request message through a first interface between the BSS and an SRNS, and the handover request message contains identification information of MS and relevant information of RAB; according to the identification information of theMS and the relevant information of the RAB, the BSS sets up a first communication link between the BSS and the SRNS and a second communication link between the BSS and the MS for the handover. In the embodiment of the invention, the BSS receives the handover request message which is sent by the SRNS and contains the identification information of the MS and the relevant information of the RAB thro ugh the first interface, and sets up the first communication link between the BSS and the SRNS and the second communication link between the BSS and the MS for the handover according to the identification information of the MS and the relevant information of the RAB. Compared with the technical proposal in the prior art, the interaction with a core network in the process of handover among the packet switching domain systems can be reduced, thus reducing signaling load of the core network and shortening time delay of the core network.

Description

Method, device and system for switching between packet domain systems

Technical Field

The embodiment of the invention relates to the technical field of mobile communication, in particular to a method, a device and a system for switching between Packet Switching (PS) domain systems.

Background

A third Generation digital communication (3rd Generation, 3G for short) network mainly includes two parts, an access network and a core network. A Wideband Code Division Multiple Access (WCDMA) is one of 3G, and an Access Network thereof is a Universal Mobile Telecommunications System (UMTS) terrestrial Radio Access Network (UTRAN). And the access networks of 2.5G communication systems include, but are not limited to: general Packet Radio Service (GPRS)/EDGE (EDGE) Radio Access Network (GSM EDGE Radio Access Network, GERAN) and other Radio Access networks for improving Data rate.

In the prior art, inter-system handover from UMTS to GPRS PS domain can be achieved through a cell reselection procedure. However, the inventor finds that the prior art has the following defects in the process of implementing the invention:

on one hand, a Serving GPRS Support Node (SGSN) in a core network needs to obtain a sequence number of a next Packet Data Unit (PDU) for uplink and downlink transmission through an SRNS context transfer flow between the Serving GPRS support node (SRNS) and a source Serving Radio Network Subsystem (SRNS), so that a signaling load of a system and a switching delay are increased; on the other hand, the packet data packet on the source SRNS needs to be forwarded to the SGSN to which the packet data packet belongs, and the SGSN forwards the packet data packet to a Base Station Subsystem (BSS), which also increases the time delay of handover.

It is understood that the foregoing has been described only with respect to PS domain intersystem handover from UMTS to GPRS, but that similar problems exist with PS domain intersystem handover from other 3G to 2.5G systems.

Disclosure of Invention

The embodiment of the invention provides a method, a device and a system for switching between PS domain systems, which are used for reducing signaling interaction with a core network and realizing reduction of signaling load of the core network and switching time delay.

The embodiment of the invention provides a switching method between PS domain systems, which comprises the following steps:

the BSS receives a switching request message sent by the SRNS through a first interface between the BSS and the SRNS, wherein the switching request message carries identification information of the MS and related information of the RAB;

and the BSS establishes a first communication link between the BSS and the SRNS and a second communication link between the BSS and the MS for the switching according to the identification information of the MS and the related information of the RAB.

An embodiment of the present invention further provides a BSS, including:

a receiving module, configured to receive a handover request message sent by the SRNS through a first interface between the SRNS and the receiving module, where the handover request message carries identification information of the MS and related information of an RAB;

and the establishing module is used for establishing a first communication link between the establishing module and the SRNS and a second communication link between the establishing module and the MS for the switching between the PS domain systems according to the identification information of the MS and the related information of the RAB.

The embodiment of the invention also provides a system for switching between PS domain systems, which comprises the BSS and the SRNS which is communicated with the BSS.

As can be seen from the foregoing technical solutions, in the embodiments of the present invention, the BSS receives, through the first interface between the BSS and the SRNS, the handover request message that is sent by the SRNS and carries the identification information of the MS and the related information of the RAB, and establishes the first communication link between the BSS and the SRNS and the second communication link between the BSS and the MS for the handover using the identification information of the MS and the related information of the RAB. Compared with the technical scheme in the prior art, the interaction between the PS domain system and the core network in the switching process is reduced, so that the signaling load of the core network and the switching time delay can be reduced.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a flowchart illustrating a handover method between PS domain systems according to an embodiment of the present invention;

fig. 2 is a flowchart illustrating a handover method between PS domain systems according to a second embodiment of the present invention;

fig. 3 is a schematic diagram of a user plane protocol stack of an Iur-g interface in the second embodiment of the present invention;

fig. 4 is a flowchart illustrating a handover method between PS domain systems according to a third embodiment of the present invention;

fig. 5 is a schematic diagram of a PS domain control plane protocol stack in the third embodiment of the present invention;

fig. 6 is a schematic structural diagram of a base station subsystem according to a fourth embodiment of the present invention;

fig. 7 is a schematic structural diagram of a base station subsystem according to a fifth embodiment of the present invention;

fig. 8 is a schematic structural diagram of a base station subsystem according to a sixth embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the embodiment of the present invention, a handover between PS domain systems from UMTS to GPRS by a Mobile Station (MS) in CELL _ FACH or CELL _ DCH state is taken as an example for description.

Fig. 1 is a flowchart illustrating a method for switching between PS domain systems according to an embodiment of the present invention, as shown in fig. 1, the method for switching between PS domain systems according to this embodiment may include the following steps:

step 101, a BSS receives a Handover Request (Handover Request) message sent by an SRNS through a first interface between the BSS and the SRNS, wherein the Handover Request message carries identification information of an MS and related information of a Radio Access Bearer (RAB for short);

step 102, the BSS establishes a first communication link between the BSS and the SRNS and a second communication link between the BSS and the MS for the handover according to the identification information of the MS and the related information of the RAB.

In this embodiment, the BSS receives, through the first interface between the BSS and the SRNS, a handover request message that is sent by the SRNS and carries identification information of the MS and related information of the RAB, and establishes a first communication link between the BSS and the SRNS and a second communication link between the BSS and the MS for the handover by using the identification information of the MS and the related information of the RAB. Compared with the technical scheme in the prior art, the switching method between the PS domain systems provided by this embodiment reduces interaction with the core network in the switching process between the PS domain systems, so as to reduce the signaling load of the core network and the time delay of switching.

Fig. 2 is a flowchart illustrating a handover method between PS domains according to a second embodiment of the present invention, where in this embodiment, it is assumed that an SGSN to which a source SRNS belongs and an SGSN to which a target BSS belongs are the same SGSN (handover in this scenario is to be performed without switching between SGSNs). It should be noted that the cross-SGSN procedure is only a procedure between the source SGSN and the target SGSN, and the inter-SGSN procedure is an existing technique, and is not described in detail in this embodiment.

As shown in fig. 2, the handover method between PS domain systems of this embodiment may include the following steps:

step 201, a source SRNS sends a Cell reselection command (Cell Change Order) message to an MS, stops sending a current downlink packet data packet, and buffers the downlink packet data packet;

in this step, when the MS performing the PS domain data service in the UMTS starts the compression mode to perform inter-system measurement, a measurement report including measurement results of neighboring GPRS cells is periodically reported to the source SRNS. When there is a measurement result of a GPRS Cell (i.e., a handover target Cell) that satisfies a Cell reselection trigger condition, the source SRNS may send a Cell reselection command (Cell Change Order) message to the MS to command the MS to start inter-system handover, stop sending a current downlink packet data packet, and buffer the downlink packet data packet. The triggering condition that satisfies the cell reselection is preset, for example: when a Received Signal Strength Indicator (RSSI) of a GPRS cell exceeds a system-defined threshold, it is determined that a cell reselection condition is satisfied.

Step 202, the source SRNS sends a handover request (handover request) message to the target BSS through the Iur-g interface, wherein the handover request message carries identification information of the MS and related information of the RAB;

the identification information of the MS may be a temporary mobile Station Identity (P-TemporaryMobile Station Identity, P-TMISI for short) in the PS domain.

The related information of the RAB may include: RAB id, RAB Quality of service (QoS) parameters, transport layer address, etc.

Step 203, the target BSS receives the handover request message, and establishes a first communication link between the target BSS and the source SRNS and a second communication link between the target BSS and the MS according to the relevant information of the RAB and the identification information of the MS;

in this step, the first communication link and the second communication link established by the target BSS may be used for signaling interaction for subsequent routing area update, specifically, the target BSS may perform signaling interaction for routing area update with the source SRNS and the MS through the first communication link and the second communication link, respectively, and after the routing area update is completed, the target BSS sends a handover response message to the source SRNS through the first communication link (Iur-g interface connection).

Step 204, the MS receives the cell reselection command message, and sends a Routing Area Update Request (Routing Area Update Request) message to the target BSS through the second communication link, where the Routing Area Update Request message carries identification information of the MS;

step 205, the target BSS receives the routing area update request message, associates the routing area update request message to the first communication link according to the identification information of the MS, and forwards the routing area update request message to the source SRNS through the first communication link;

step 206, the source SRNS receives the routing area update request message, and sends the routing area update request message to the SGSN through a third communication link (Iu-PS interface connection);

step 207, the SGSN receives the Routing Area update request message, verifies that the MS establishes a Mobility Management (MM) context and a Packet Data Protocol (PDP) context for the MS after a new Routing Area (RA for short) is legal;

step 208, the SGSN returns a Routing Area Update Accept (Routing Area Update Accept) message to the source SRNS through a third communication link (Iu-PS interface connection);

step 209, the source SRNS receives the routing area update accept message, and forwards the routing area update accept message to the target BSS through the first communication link;

step 210, the target BSS receives the routing area update accept message, and sends the routing area update accept message to the MS through the second communication link;

step 211, the MS receives the Routing Area Update accept message, and sends a Routing Area Update Complete (Routing Area Update Complete) message to the target BSS through the second communication link;

step 212, the target BSS receives the routing area update completion message, and forwards the routing area update completion message to the source SRNS through the first communication link;

step 213, the source SRNS receives the routing area update complete message, and sends the routing area update complete message to the SGSN through a third communication link (Iu-PS interface connection);

step 214, after the update of the routing area is completed, the target BSS sends a handover acknowledgement (handover acknowledge) message to the source SRNS through the first communication link (Iur-g interface connection);

step 215, the source SRNS receives the handover response message, and sends the cached downlink packet data packet to the target BSS through the first communication link;

in step 202, the handover request message sent by the source SRNS to the target BSS through the Iur-g interface may also carry a context of the SRNS, so that the target BSS can send the downlink packet data packet to the MS through the second communication link. The SRNS context stores a Packet Data Unit (PDU) sequence number of a GPRS Tunneling Protocol (GTP for short) to be transmitted next, and stores a PDCP sequence number of a Packet Data Convergence Protocol (PDCP) to be transmitted next for a Packet Data Convergence Protocol (PDCP) procedure.

Step 216, the target BSS receives the downlink packet data packet, and sends the downlink packet data packet to the MS through the second communication link according to the context of the source SRNS.

In this embodiment, after receiving the handover request message, the target BSS establishes a first communication link between the target BSS and the source SRNS and a second communication link between the target BSS and the MS according to the identification information of the MS and the related information of the RAB carried in the handover request message. The target BSS interacts with the MS and the source SRNS, then the source SRNS interacts with the SGSN, relevant information of the MS and the SGSN in a routing area updating process is transferred through the second communication link, the first communication link and the third communication link so as to complete the updating of the routing area, and the target BSS returns a switching response message to the source SRNS after the routing updating is successful. And then, the source SRNS sends the downlink packet data packets cached by the source SRNS to the target BSS through the first communication link, and the target BSS sends the downlink packet data packets to the MS through the second communication link.

In this embodiment, through the established first communication link between the target BSS and the source SRNS, the source SRNS can directly perform signaling interaction with the target BSS without passing through the SGSN to which the source SRNS belong, thereby reducing interaction with the core network during the inter-system handover in the PS domain, and reducing the signaling load of the core network and the time delay of the handover; through the established first communication link between the target BSS and the source SRNS, the downlink packet data packet on the source SRNS can be directly transmitted to the target BSS through the first communication link without being forwarded to the SGSN to which the downlink packet data packet belongs, and the time delay of handover is further reduced.

In the second embodiment of the present invention, the transfer of the handover request message and the handover response message is supported by extending a Radio network subsystem Application Part (RNSAP for short) protocol of a signaling plane (a signaling plane of the first communication link) of an Iur-g interface between the source SRNS and the target BSS. It is also possible to support the forwarding of the buffered downlink packet data packets on the source SRNS directly to the target BSS through the newly added user plane of the Iur-g interface (user plane of the first communication link), and after the handover, the uplink packet data packets of the MS are forwarded by the source SRNS to the SGSN directly through the Iur-g interface connection. Fig. 3 is a schematic diagram of a user plane Protocol stack of an Iur-g interface in the second embodiment of the present invention, and as shown in fig. 3, a processing Protocol of the user plane is a GPRS Tunneling Protocol (GTP-U for short) of the user plane, a GTP-U layer, a UDP layer, an IP layer, an L2 layer, and an L1 layer may be configured on the BSS and the SRNS (interfaces of the BSS and the SRNS are Iur-g interfaces), and specific protocols adopted may include a GTP-U Protocol, a UDP Protocol, an IP Protocol, an L2 Protocol, and an L1 Protocol, for example: from top to bottom, GTP-U/UDP/IP/L2/L1 can be used. The target BSS needs to support processing of a 2G network user plane, and a function of a Logical Link Control (LLC)/subnet related Convergence Protocol (SNDCP) Protocol originally implemented on the SGSN needs to be moved down to the target BSS for implementation. In the protocol processing process of the target BSS, the SNDCP compresses a sub-network related convergence protocol packet data unit (SN-PDU) from an LLC layer and then delivers the compressed SN-PDU as a network protocol packet data unit (N-PDU) to a GTP-U for processing.

Fig. 4 is a flowchart illustrating a handover method between PS domains according to a third embodiment of the present invention, where in this embodiment, it is assumed that an SGSN to which a source SRNS belongs and an SGSN to which a target BSS belongs are the same SGSN (handover in this scenario is to be performed without switching between SGSNs). It should be noted that the cross-SGSN procedure is only a procedure between the source SGSN and the target SGSN, and the inter-SGSN procedure is an existing technique, and is not described in detail in this embodiment.

As shown in fig. 4, the handover method between PS domain systems of this embodiment may include the following steps:

step 401, the source SRNS sends a cell reselection command message to the MS, stops sending the current downlink packet data packet, and buffers the downlink packet data packet;

in this step, when the MS performing the PS domain data service in the UMTS starts the compression mode to perform inter-system measurement, a measurement report including measurement results of neighboring GPRS cells is periodically reported to the source SRNS. When there is a measurement result of a GPRS cell (i.e., a handover target cell) satisfying a cell reselection trigger condition, the source SRNS may send a cell reselection command message to the MS to command the MS to start inter-system handover, stop sending a current downlink packet data packet, and buffer the downlink packet data packet. The triggering condition that satisfies the cell reselection is preset, for example: and when the RSSI of the GPRS cell exceeds a threshold value defined by a system, the cell reselection condition is considered to be met.

Step 402, source SRNS sends switching request message to target BSS through Iur-g interface, the switching request message carries identification information of MS and related information of RAB;

the identification information of the MS may be P-TMISI.

The related information of the RAB may include RAB identification, RAB QoS parameters, transport layer address, and other parameters.

Step 403, the target BSS receives the handover request message, and establishes a first communication link between the target BSS and the source SRNS and a second communication link between the target BSS and the MS according to the relevant information of the RAB and the identification information of the MS;

in this step, the second communication link established by the target BSS may be used for signaling interaction for routing area update, and in subsequent steps, a fourth communication link between the target BSS and the SGSN may be established, specifically, the target BSS may perform signaling interaction for routing area update with the MS and the SGSN through the second communication link and the fourth communication link, respectively, and after the routing area update is completed, the target BSS sends a handover response message to the source SRNS through the first communication link (Iur-g interface connection).

Step 404, the MS receives the cell reselection command message, and sends a routing area update request message to the target BSS through the second communication link, where the routing area update request message carries identification information of the MS;

step 405, the target BSS receives the routing area update request message, establishes a fourth communication link (Iu-PS interface connection) between the target BSS and the SGSN, and forwards the routing area update request message to the SGSN through the newly established fourth communication link;

step 406, the SGSN receives the routing area update request message, verifies that the MS is legitimate in the new routing area, and establishes a Mobility Management (MM) context and a Packet Data Protocol (PDP) context for the MS;

step 407, the SGSN returns a routing area update accept message to the target BSS through a fourth communication link (Iu-PS interface connection);

step 408, the target BSS receives the routing area update accept message, and sends the routing area update accept message to the MS through the second communication link;

step 409, the MS receives the routing area update acceptance message and sends a routing area update completion message to the target BSS through the second communication link;

step 410, the target BSS receives the routing area update completion message, and forwards the routing area update completion message to the SGSN through the fourth communication link (Iu-PS interface connection);

step 411, after the update of the routing area is completed, the target BSS sends a handover response message to the source SRNS through the first communication link (Iur-g interface connection);

step 412, the source SRNS receives the handover response message, and sends the cached downlink packet data packet to the target BSS through the first communication link;

step 413, the target BSS receives the downlink packet data packet, and sends the downlink packet data packet to the MS through the second communication link according to the context of the source SRNS.

In step 402, the handover request message sent by the source SRNS to the target BSS through the Iur-g interface may also carry a context of the SRNS, so that the target BSS can send the downlink packet data packet to the MS through the second communication link. The SRNS context holds the GTPPDU sequence number to be transmitted next, and for lossless PDCP procedures, the SRNS context also holds the PDCP sequence number to be transmitted next.

In this embodiment, after receiving the handover request message, the target BSS establishes a first communication link between the target BSS and the source SRNS and a second communication link between the target BSS and the MS according to the identification information of the MS and the related information of the RAB carried in the handover request message. The target BSS interacts with the MS and the SGSN, related information of the MS and the SGSN in a routing area updating process is transferred through a second communication link and a fourth communication link (Iu-PS interface connection) between the target BSS and the SGSN, which is established by the target BSS, so as to complete the updating of the routing area, and the target BSS returns a switching response message to the source SRNS after the routing updating is successful. And then, the source SRNS sends the downlink packet data packets cached by the source SRNS to the target BSS through the first communication link, and the target BSS sends the downlink packet data packets to the MS through the second communication link.

Compared with the above two embodiments of the present invention, the route area update procedure in this embodiment is completed by the interaction between the target BSS and the MS and the SGSN, and the downlink packet data packet cached on the source SRNS is still transmitted through the first communication link and the second communication link, so that the characteristics of separation of the bearer and the control of the PS domain are realized, respective capacity expansion of the control plane and the user plane is supported, and the flexibility of networking is increased.

Fig. 5 is a schematic diagram of a PS domain control plane protocol stack in the third embodiment of the present invention, as shown in fig. 5, an LLC layer, a Radio Link Control (RLC) layer, a Medium Access Control (MAC) layer, and a physical Radio Frequency (RF) layer may be configured on an MS and a BSS (the interface between the MS and the BSS is a Um interface), and the specific protocols adopted may include an LLC protocol, an RLC protocol, a MAC protocol, and an RF protocol, for example: LLC/RLC/MAC/RF can be from top to bottom; radio Access Network Application Part (RANAP) layer, Signaling Connection Control Part (SCCP) layer, Signaling Bearer (Signaling Bearer) layer, L2 layer, and L1 layer may be configured on SGSN and BSS (interfaces of both are Iu-PS interfaces), and the specific protocols used may include RANAP protocol, SCCP protocol, Signaling Bearer protocol, L2 protocol, and L1 protocol, for example: from top to bottom, RANAP/SCCP/Signaling bearer/L2/L1 can be used. In the third embodiment of the present invention, Gb interface signaling between the target BSS and the SGSN of the core network is unified into Iu-PS interface signaling, the target BSS interacts with the MS and the SGSN, and the second communication link is connected to the Iu-PS interface between the target BSS and the SGSN of the core network to transfer related information of the MS and the SGSN in the route area update procedure, so as to complete the route area update.

It should be noted that: the above embodiments of the present invention only describe the transmission of the downlink packet data packet on the source SRNS in the PS domain inter-system handover process from UMTS to GPRS, and after successful handover to GPRS, the communication link for the transmission of the uplink packet data packet of the MS and the communication link for the transmission of the downlink packet data packet are the same, but the directions are opposite, and are not described herein again.

It should be noted that: while, for purposes of simplicity of explanation, the foregoing method embodiments have been described as a series of acts or combination of acts, it will be appreciated by those skilled in the art that the present invention is not limited by the illustrated ordering of acts, as some steps may occur in other orders or concurrently with other steps in accordance with the invention. Further, those skilled in the art should also appreciate that the embodiments described in the specification are preferred embodiments and that the acts and modules referred to are not necessarily required by the invention.

In the foregoing embodiments, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.

Fig. 6 is a schematic structural diagram of a base station subsystem according to a fourth embodiment of the present invention, and as shown in fig. 6, the base station subsystem according to this embodiment may include a receiving module 61 and an establishing module 62. The receiving module 61 receives a handover request message sent by the SRNS through a first interface between the receiving module and the SRNS, where the handover request message carries identification information of the MS and related information of an RAB, and the establishing module 62 establishes a first communication link between the receiving module and the SRNS and a second communication link between the receiving module and the MS for handover between PS domain systems according to the identification information of the MS and the related information of the RAB.

The BSS in the first embodiment of the present invention, the BSS in the second embodiment of the present invention, and the BSS in the third embodiment of the present invention may all be implemented by the BSS provided in this embodiment.

In this embodiment, the receiving module receives, through the first interface between the BSS and the SRNS, a handover request message that is sent by the SRNS and carries identification information of the MS and related information of the RAB, and the establishing module establishes, for the current PS-domain inter-system handover, a first communication link between the BSS and the SRNS and a second communication link between the BSS and the MS by using the identification information of the MS and the related information of the RAB. Compared with the technical scheme in the prior art, the BSS provided by the embodiment reduces interaction with the core network in the handover process between the PS domain systems, so that the signaling load of the core network and the handover delay can be reduced.

Fig. 7 is a schematic structural diagram of a base station subsystem according to a fifth embodiment of the present invention, as shown in fig. 7, in this embodiment, the first communication link and the second communication link established by the establishing module 62 are used for signaling interaction of routing area update, and the BSS of this embodiment may further include a first updating module 71 and a first responding module 72. The first updating module 71 performs signaling interaction of routing area update with the SRNS and the MS through the first communication link and the second communication link established by the establishing module 62, and the first responding module 72 sends a handover response message to the SRNS through the first interface after the routing area update is completed.

In this embodiment, the first update module interacts with the MS and the source SRNS, and relays related messages between the MS and the SGSN in the routing area update procedure through the second communication link and the first communication link established by the establishment module, so as to complete the routing area update.

Further, the handover request message received by the receiving module 61 also carries a context of the SRNS, and the BSS of this embodiment may further include a first transmitting module 73, configured to receive, according to the context of the SRNS, the buffered downlink packet data packet sent by the SRNS through the first communication link established by the establishing module 62, and send the downlink packet data packet to the MS through the second communication link established by the establishing module 62.

In this embodiment, by establishing the first communication link between the target BSS and the source SRNS, which is established by the establishing module, the source SRNS can directly perform signaling interaction with the target BSS without passing through the SGSN to which the source SRNS belong, thereby reducing interaction with the core network during the inter-system handover process in the PS domain, and reducing the signaling load of the core network and the time delay of the handover; through the first communication link between the target BSS and the source SRNS established by the establishing module, the downlink packet data packet on the source SRNS can be directly transmitted to the target BSS through the first communication link without being forwarded to the SGSN to which the downlink packet data packet belongs, and the time delay of handover is reduced.

Fig. 8 is a schematic structural diagram of a base station subsystem according to a sixth embodiment of the present invention, as shown in fig. 8, in this embodiment, the second communication link established by the establishing module 62 is used for signaling interaction of routing area update, and a fourth communication link exists between the BSS and the SGSN, and the BSS of this embodiment may further include a second updating module 81 and a second response module 82. The second updating module 81 performs signaling interaction for updating the routing area with the MS and the SGSN through the second communication link and the fourth communication link established by the establishing module 62, and the second responding module 82 sends a handover responding message to the SRNS through the first interface after the routing area is updated.

In this embodiment, the second updating module interacts with the MS and the SGSN, and relays related messages of the MS and the SGSN in the routing area updating process through the second communication link established by the establishing module and a fourth communication link (Iu-PS interface connection) between the target BSS and the SGSN established by the target BSS, so as to complete the routing area updating. Compared with the fifth embodiment of the present invention, the second update module in this embodiment is a routing area update procedure completed through interaction with the MS and the SGSN, and the downlink packet data packet cached on the source SRNS is still transmitted through the first communication link and the second communication link, so that the characteristics of separation of bearer and control in the PS domain are realized, respective capacity expansion of the control plane and the user plane is supported, and the flexibility of networking is increased.

Further, the handover request message received by the receiving module 61 also carries a context of the SRNS, and the BSS of this embodiment may further include a first transmitting module 83, configured to receive, according to the context of the SRNS, the buffered downlink packet data packet sent by the SRNS through the first communication link established by the establishing module 62, and send the downlink packet data packet to the MS through the second communication link established by the establishing module 62.

An embodiment of the present invention may further provide a system for handover between PS domains, including a BSS and an SRNS, where the BSS is provided in the fourth embodiment of the present invention, the fifth embodiment of the present invention, and the sixth embodiment of the present invention, and the SRNS communicates with the BSS. The SRNS may include a sending module, configured to send the handover request message to the BSS through a first interface with the BSS. The handover request message may further carry a context of the SRNS, and accordingly, the SRNS may further include a second transfer module, configured to send the buffered downlink packet data packet to the BSS through the first communication link established by the BSS establishing module.

In this embodiment, through the first communication link between the target BSS and the source SRNS established by the target BSS, the source SRNS can directly perform signaling interaction with the target BSS without passing through the SGSN to which the source SRNS belong, thereby reducing interaction with the core network during the inter-system handover in the PS domain, and reducing the signaling load of the core network and the time delay of the handover; through a first communication link between a target BSS and a source SRNS established by the target BSS, a downlink packet data packet on the source SRNS can be directly transmitted to the target BSS through the first communication link without being forwarded to an SGSN to which the downlink packet data packet belongs, and the time delay of handover is reduced.

Those of ordinary skill in the art will understand that: all or part of the steps for implementing the method embodiments may be implemented by hardware related to program instructions, and the program may be stored in a computer readable storage medium, and when executed, the program performs the steps including the method embodiments; and the aforementioned storage medium includes: various media that can store program codes, such as ROM, RAM, magnetic or optical disks.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. A method for switching between packet domain systems, comprising:

a target base station subsystem receives a switching request message sent by a source service wireless network subsystem through a first interface between the target base station subsystem and the source service wireless network subsystem, wherein the switching request message carries identification information of a mobile station and related information of wireless access bearer;

the target base station subsystem establishes a first communication link between the target base station subsystem and the source service wireless network subsystem and a second communication link between the target base station subsystem and the mobile station for the switching according to the identification information of the mobile station and the related information of the wireless access bearer; wherein:

the first communication link and the second communication link are used for signaling interaction of routing area update; the method further comprises the following steps:

the target base station subsystem respectively carries out signaling interaction of routing area updating with the source service wireless network subsystem and the mobile station through the first communication link and the second communication link;

after the routing area is updated, the target base station subsystem sends a switching response message to the source service wireless network subsystem through the first communication link;

or

The second communication link is used for signaling interaction of routing area update, and a fourth communication link exists between the target base station subsystem and the serving general packet radio service support node; the method further comprises the following steps:

the target base station subsystem respectively carries out signaling interaction of routing area updating with the mobile station and the serving general packet radio service support node through the second communication link and the fourth communication link;

and after the routing area is updated, the target base station subsystem sends a switching response message to the source service wireless network subsystem through the first communication link.

2. The method of claim 1, wherein the handover request message further carries a context of an active serving radio network subsystem, and wherein the method further comprises:

and the target base station subsystem receives the cached downlink packet data packet sent by the source service wireless network subsystem through the first communication link according to the context of the source service wireless network subsystem, and sends the downlink packet data packet to the mobile station through the second communication link.

3. The method of claim 2, wherein the first interface is an Iur-g interface, and wherein a processing protocol of the first communication link is a general packet radio service tunneling protocol of a user plane.

4. A target base station subsystem, comprising:

a receiving module, configured to receive, through a first interface between the source serving radio network subsystem and the source serving radio network subsystem, a handover request message sent by the source serving radio network subsystem, where the handover request message carries identification information of a mobile station and related information of a radio access bearer;

an establishing module, configured to establish a first communication link with the source service radio network subsystem and a second communication link with a mobile station for inter-packet domain system handover according to the identification information of the mobile station and the related information of the radio access bearer; wherein:

the first communication link and the second communication link are used for signaling interaction of routing area update; the target base station subsystem further comprises:

a first updating module, configured to perform signaling interaction for updating a routing area with the source serving radio network subsystem and the mobile station through the first communication link and the second communication link, respectively;

the first response module is used for sending a switching response message to the source service wireless network subsystem through the first communication link after the updating of the routing area is finished;

or

The second communication link is used for signaling interaction of routing area update, and a fourth communication link exists between the target base station subsystem and the serving general packet radio service support node; the target base station subsystem further comprises:

a second updating module, configured to perform signaling interaction of routing area update with the mobile station and the serving gprs support node through the second communication link and the fourth communication link, respectively;

and the second response module is used for sending a switching response message to the source service wireless network subsystem through the first communication link after the routing area is updated.

5. The target base station subsystem of claim 4, wherein the handover request message further carries a context of an active serving radio network subsystem, and wherein the target base station subsystem further comprises:

and the first transmission module is used for receiving the cached downlink packet data packet sent by the source service wireless network subsystem through the first communication link according to the context of the source service wireless network subsystem and sending the downlink packet data packet to the mobile station through the second communication link.

6. A system for inter-system handover in a packet domain, comprising a target base station subsystem according to claim 4 or 5, and a source serving radio network subsystem in communication with the target base station subsystem; wherein,

the source service radio network subsystem comprises a sending module, which is used for sending the switching request message to the target base station subsystem through a first interface between the source service radio network subsystem and the target base station subsystem.