CN101577897B - Method for informing IMS about belonging network of PDN GW allocated to UE - Google Patents

Abstract

The invention provides a method for informing IMS about belonging network of PDN GW allocated to UE. The method comprises the following steps that: user equipment UE is attached to a system architecture evolution SAE network; the SAE network establishes an IP bearer for the UE and returns the information of a belonging network of a packet data network gateway PDN GW allocated to the UE to the UE; the UE receives the information of the belonging network of the PDN GW and then stores the information in a local position; the UE carries the information of the belonging network of the PDN GW to an IP multimedia subsystem IMS network through session initiation protocol SIP signaling; and the IMS network judges the belonging network of the PDN GW according to the information of the belonging network of the PDN GW. Through the method provided by the invention, the IMS network can be informed whether a current media routing mode of the UE is an LBO mode, and converts the media routing mode of the UE from the LBO mode to an HR mode according to need.

Description

IMS is known as the method for the belonging network of the PDN GW that UE distributes

Technical field

The present invention relates to the communications field, more specifically, relate to a kind of under roaming condition, UE (UserEquipment, subscriber equipment) by LTE/SAE (Long term Evolution/System ArchitectureEvolution, Long Term Evolution/System Architecture Evolution) access network is registered to IMS (the IPMultimedia Core Network Subsystem of home network, IP Multimedia System) network, IMS is known as the method for the belonging network of the PDN GW (Packet Data Network Gateway, packet data network gateway) that UE distributes.

Background technology

The IMS system is the core of communication network of new generation, its distinguishing feature is to have adopted Session initiation Protocol (Session Initiation Protocol, be called for short SIP) system, communication is irrelevant with access, can possess multiple media business controlled function and separate with bearing capacity, calls out and separates with session, application separates with service, business and network detach, and multiple abilities such as mobile network and internet service fusion, the trend of communication network fusion development has been complied with in the proposition of IMS.

Development along with network architecture flattening, and the appearance of the removable access way of multiple high-speed wideband also impels mobile communications network to propose the framework theory of future generation of LTE/SAE, comprise and make the wireless communication system of evolution that higher transmission rate can be provided, shorter transmission delay, lower cost, support 3GPP (3rd Generation Partnership Project simultaneously, third generation partner program) mobility between the inner connecting system, and the mobility between 3GPP connecting system and the non-3GPP connecting system or the like.Simultaneously, LTE/SAE also will impel the IMS framework to be able to evolution and development as a kind of access means in IMS territory.

In the SAE research process, roaming is an important use scene, along with roaming use more and more general, how to improve the utilization ratio of roaming scence lower network, reduces the circuitous of unnecessary medium route, becomes an important topic of SAE research.

In order to solve the continuity problem of signaling under the roaming condition, the 3GPP tissue has proposed to adopt mobile IP technology to realize that the uninterrupted signaling from home network to the visit net connects.But the introducing of mobile IP technology, the Media Stream that has produced visit ground must travel back across the triangle routing issue of home network, causes media transmission efficiency greatly to reduce.

Because mobile IP introduces the triangle routing issue that is brought, the 3GPP tissue has proposed this locality of medium routes and has produced pattern (Local Breakout is called for short the LBO pattern) in order to solve.Under the LBO pattern, medium turnover visit net all need not to travel back across home network.With respect to the LBO pattern be the home network route pattern (Home Routed, be called for short HR pattern) of medium route, promptly Media Stream must travel back across home network.

In order to realize the LBO pattern, the 3GPP tissue has proposed some kinds of concrete application models, wherein a kind of being referred to as: two IP patterns.That is, when UE roamed in the visit net, visit net and home network were UE and set up the IP carrying, the IP carrying of visit net is used for away the medium route, the IP of home network carrying is used for away signaling control, and promptly signaling adopts mobile IP technology through home network, and medium produce from visit net this locality.Under this pattern, home network, visit net are UE and have distributed an IP address, and that wherein home network is that UE distributed is mobile IP.This pattern can realize the continuity of signaling control under roaming condition, can solve the low efficiency problem that the medium route travels back across home network again.Under this pattern, require to distribute P-CSCF, the S-CSCF of home network into UE.

Another application model is single IP pattern: be that UE sets up the IP carrying only promptly by the visit net, and the distributing IP address, the medium route directly produces from visit net this locality.

Fig. 1 shows a kind of main framework of realizing the LBO pattern under the SAE network, and this framework can be supported two IP patterns and single IP pattern simultaneously.UE is linked into the IMS business by the SAE Access Network net is provided.Wherein, the SAE network is arranged in visited network, and the bottom access service is provided, and the IMS service network is arranged in home network, and business service is provided.

In Fig. 1, the main network element of SAE network comprises:

E-UTRAN (Evolved UTRAN, the wireless access network of evolution): follow-on wireless access network can provide higher up-downgoing speed, lower transmission delay and reliable more wireless transmission.Wherein the main network entity of E-UTRAN is eNodeB;

MME (Mobility Management Entity, mobile management entity): the chain of command functional entity, be in charge of and store the UE context (such as the UE/ user ID, mobility management states, user security parameters etc.), for the user distributes temporary mark, when quartering at this tracing area or this network, is responsible for UE this user is carried out authentication;

SAE GW (SAE Gateway, SAE gateway): the user plane functions entity, be responsible for the user face data route and handle, be divided into Serving GW (gateway is called for short S-GW) and two kinds of SAE GW of PDN GW.S-GW is mobile anchor point between SAE system and traditional 3GPP system and the mobile anchor point between the E-UTRAN.PDN GW be used to the terminate downlink data of the UE that is in idle state when the downlink data that mails to UE arrives, is initiated paging, and the context of management and storage UE, such as IP bearer service parameter and network internal routing iinformation etc.

The main network element of IMS business network comprises:

Home subscriber server (Home Subscriber Server is called for short HSS): the data of being in charge of CS territory, packet domain (PS) and IMS territory;

CSCF (CallSession Control Function, be called for short CSCF): the core network element of control conversation procedure, comprise: Proxy Call Session Control Function (Proxy-CSCF, abbreviation P-CSCF), query call conversation control function (Interrogating-CSCF, abbreviation I-CSCF), service call conversation control function (Serving-CSCF is called for short S-CSCF);

"Policy and Charging Rules Function (Policy and Charging Rules Function, be called for short PCRF): be the function point of the connection of control medium, medium flow, execution charging etc., a part that belongs to PCC (Policy andCharging Control, the strategy and the control of chargeing) function structure.

In framework shown in Figure 1,, then can realize two IP patterns if the PDN GW (Visited PDN GW is called for short V-PDN GW) of the PDN GW of home network (Home PDN GW is called for short H-PDN GW), visit net is UE distributing IP address.If, then be single IP pattern only by V-PDN GW distributing IP address.Referring to Fig. 1,, then be home network route pattern (HR) if the path of medium route is " UE-E-UTRAN-S-GW-H-PDN GW "; If the path of medium route is " UE-E-UTRAN-S-GW-V-PDN GW ", then produce pattern (LBO) for visit net this locality.

Owing to use the mode of two IP to realize that this locality of medium route produces, its technical scheme more complicated, so the leading mode of using single IP of 3GPP normal structure realizes that this locality of medium route produces.When using single IP to realize that this locality of medium route is produced, how to realize that the medium route from the conversion of LBO pattern to the HR pattern, is the problem that need discuss.Media routing mode is from the conversion of LBO pattern to the HR pattern, and its demand may be because home network requires to carry out Lawful Interception, perhaps because the needs that some particular service is handled, as the initiation of convention business.

Fig. 2 shows under single IP pattern, how to realize the LBO pattern of medium route, and to the process of HR mode switch.In Fig. 2, PDN GW is positioned at the visit net, can distribute the IP address that belongs to the visit net for UE.P-CSCF is positioned at home network, and P-CSCF also can be positioned at the visit net certainly, does not influence overall architecture.By the control of P-CSCF, on the path of medium route, seal in IMS IAD (IMS Access Gateway is called for short IMS AGW), can be the HR pattern from the LBO mode switch with the medium route.

But, under the framework of Fig. 2, P-CSCF must at first know the medium route of UE current whether be the LBO pattern, can require the medium route is the HR pattern from the LBO mode switch.Otherwise if the current media route of UE outlet is home network (being the HR pattern), but P-CSCF and not knowing the medium route then can occur and transfer the HR pattern to from the HR pattern, conversion invalid and waste promptly occurred.

Whether the medium route of judging UE is the LBO pattern, judges that promptly whether the current medium outlet pathway of UE is at the visit net.Because PDN GW is responsible for the Media Stream of process user, and the medium of UE outwards produce from PDN GW, therefore judge the medium route outlet of UE, are equivalent to be judged as the PDN GW that UE distributes and are positioned at visit net or home network.

Therefore, P-CSCF is necessary to know the belonging network of the PDN GW that distributes for UE, and under the current techniques, P-CSCF can't be known as the belonging network of the PDN GW of UE distribution.

Under prior art, need be linked into the IMS territory of home network when being positioned at visited network under the UE roaming condition by the SAE Access Network.UE can ask to set up the SAE network and distribute PDN GW for it when being attached to the SAE network, sets up the IP carrying.In this process, UE has finally obtained an IP address from network, but and do not know the belonging network of the PDN GW that this IP address is associated, promptly which network the associated PDN GW in this IP address belongs to.

Fig. 3 shows under the prior art, and UE is linked into the SAE network, and the process of carrying out network attachment, distributing PDN GW, IP carrying to set up mainly may further comprise the steps:

S301, UE initiates the network attachment request in order to be linked into the SAE network to eNodeB, has wherein carried the sign of UE, the network accessibility of UE, the information such as indication of request distributing IP;

S302, eNodeB are that UE selects a MME of service for it, and will adhere to and ask to be forwarded to this MME, and the important informations such as sign with UE also carry to this MME simultaneously;

S303, MME sends position updating request to the HSS of home network, carries the sign of MME, the sign of UE in the message, to inform the current zone of being inserted of UE;

S304, HSS finds out the user data of UE according to the sign of UE, send to MME, in these certain customers' data of UE, mainly comprise: whether allow to be linked into this visit net, default APN (Access Point Name, be called for short APN), information such as amount of bandwidth, if HSS decision UE uses the PDN GW of home network, then comprise the address information of this home network PDN GW simultaneously;

In this step, at the distribution of PDN GW, HSS adopts dual mode to indicate MME how to obtain the address of PDN GW:

(1) mode 1: the concrete address of specifying an APN title and a PDN GW;

(2) mode 2: specify an APN title, and an indication is to select the home network or the PDN GW of visit net in order to indication MME.

If employingmode 1, HSS specifies the specific address (address of APN and PDN GW) of the PDN GW of a home network, and MME obtains the PDN GW of home network clearly then according to the address of the indicated PDN GW of HSS, and promptly HSS replaces MME to select.

If employing mode 2, then the HSS indication is selected PDN GW by MME, the mechanism that MME selects PDNGW is extended to a shape as a domain name form " APN.MNC.MCC.XXYY " based on: MME with APN, asks dns server this domain name mapping to be become the address of a concrete PDNGW then.Wherein, MNC is mobile network No. (Mobile Network Code is called for short MNC), and in order to identify a concrete mobile network, the visit net has different mobile network No.s with home network; MCC is mobile national number (Mobile Country Code is called for short MCC), belongs to that country in order to the sign mobile network.XXYY is a COS title, is that this APN is the concrete COS of a GPRS service such as " GPRS " expression.

For having adopted mode 2, and HSS indication MME need distribute the PDN GW of home network, then HSS need provide the mobile operator sign (APN Operator Identifier is called for short APN-OI) of an APN, and this APN-OI is exactly the word string of a shape as " APN.MNC.MCC ".If MME receives this indication of HSS, then MME will be replaced with this APN-OI by the appropriate section in the domain name " APN.MNC.MCC.XXYY " that APN expanded, and promptly can ask the dns server of home network to resolve the PDN GW address of home network according to this domain name then.

For having adopted mode 2, and the situation that HSS indication MME distributes visit network PDN GW, then generate the domain name of shape according to self moving network No., resolve the PDN GW address of local network according to the dns server of this domain name request local network as " APN.MNC.MCC.XXYY " by MME.

Be compared to mode 2, inmode 1, APN is the identifier that does not comprise OI part (Operator Identifier, Operator ID), does not promptly comprise the part of " MNC.MCC ".

S305, MME receives user data, checks whether UE is allowed access to network, returns to HSS and receives user's response;

In this step, the indication how to select PDN GW that MME returns according to HSS in the above-mentioned steps, determining being to select home network PDN GW, or visit network PDN GW.In a concrete flow process, only can select a PDN GW, can not select the PDN GW of home network and visit net simultaneously.

S306, HSS send to MME and confirm position renewal response;

S307, MME are that UE selects a S-GW, and the request of setting up default bearing to its transmission.In this request, MME inform sign, the MME of the information of S-GW necessity: UE sign, be the indication of UE distributing IP address, default bandwidth information, PDN GW address, APN etc.;

S308, S-GW sends the request set up default bearing to PDN GW, and in this request, S-GW informs the address of the information of PDN GW necessity: APN, S-GW, default bandwidth information, for the indication of UE distributing IP address etc.;

S309 (optional), if necessary, PDN GW is this UE institute's configured strategy and charging regulation, decision information to PCRF request;

S310, PDN GW sets up default bearer according to strategy and charging decision information that PCRF returns, and returns carrying to S-GW and set up response, sets up in the response in carrying, is included as UE IP address allocated information;

S311, S-GW sends the response that default bearing is set up to MME, sets up in the response in this carrying, is included as UE IP address allocated information;

S312, MME send to eNodeB and adhere to response, show that the request that is attached to network of UE is received.In this response, comprise: APN, for UE IP address allocated information etc.Do not comprise network number and country number among this APN, promptly do not comprise the suffix portion of shape such as MNC.MCC.XXXX;

S313, eNodeB sends voice bearer to UE and sets up request, requires UE to preserve the important information that carrying is set up, and open corresponding ports, in this message, carried: bearer network ID, PDN GW address, the IP address of distributing to UE, bandwidth information, APN etc.;

S314, UE sends voice bearer to eNodeB and sets up response;

S315, eNodeB notice MME attaching process is finished;

S316, MME sends more new bearer request to S-GW, notifies sign, address into the eNodeB of UE service;

S317, S-GW sends more new bearer response to MME;

S318, if PDN GW is not the HSS appointment, then MME sends position updating request to HSS, is notified to the address information that HSS is the PDN GW that UE served, HSS upgrades this information.

In step S312, the S313 of Fig. 3 flow process, MME returns to the APN information of UE by eNodeB, might be not comprise operator's sign (OI), just, do not comprise ' MNC.MCC ' such network number, therefore, the PDN GW that also just can not the district office distributes of UE be home network or the visit net.

When shown in Figure 3 adhere to, after the IP loading establishing process finishes, UE promptly is attached to the SAE network on visit ground, is linked into a PDN and has set up an IP carrying.

After UE had been assigned with the IP address, UE used this IP address to initiate the IMS registration process to home network.In registration process, UE can inform the network No. of the network that IMS inserts, but the network that UE inserted and distribute the PDN network of PDN GW for UE, might not be same, therefore, IMS operation layer (particularly being meant P-CSCF, S-CSCF) does not also know that the PDN GW of UE is (being to visit net or home network) that belongs to which network, therefore just can't know whether UE current media route pattern is the LBO pattern yet.

And then, under the LBO of single IP framework, because IMS layer (P-CSCF/S-CSCF) does not also know that the outlet (being the PDN GW that UE distributes) of the medium route of UE is positioned at visit net or home network, therefore when handling specific demand (requiring to carry out Lawful Interception), can't judge that media routing mode should be the HR pattern from the LBO mode switch as home network.

This shows, under prior art, when the IMS operation layer requires the medium route implementing when the LBO mode conversion is the HR pattern, because it is which network allocation (being that visit net or home network are distributed) that the IMS operation layer can't be known the PDN GW of UE, lack basic judgement information, thereby can't learn whether current media routing mode is the LBO pattern, and then can't require the conversion of media routing mode.

Summary of the invention

The technical problem to be solved in the present invention provides the method that a kind of IMS is known as the belonging network of the PDN GW that UE distributes, realize under the roaming condition, UE is linked into the SAE network, IMS operation layer (P-CSCF/S-CSCF) can be judged the current media routing mode of UE according to the belonging network of the PDN GW of the UE of being known, thereby can carry out the conversion of media routing mode as required.

In order to address the above problem, the invention provides the method that a kind of IMS is known as the belonging network of the PDN GW that UE distributes, may further comprise the steps:

User equipment (UE) is attached to System Architecture Evolution SAE network, described SAE network is that described UE sets up the IP carrying, and being returned as the belonging network information of the packet data network gateway PDN GW that UE distributes to described UE, described UE is kept at this locality after receiving the belonging network information of described PDN GW;

Described UE carries the network to IP Multimedia System IMS by Session initiation Protocol SIP signaling with the belonging network information of described PDN GW, and the belonging network information of the network based described PDN GW of described IMS is judged the belonging network of described PDN GW;

Wherein, the belonging network information of described PDN GW is: carry the APN APN information of Network Recognition information or independently PDN network identification mark or be indicated as the identification information that PDN GW that UE distributes belongs to home network or visit net;

The network based described belonging network information of described IMS is judged the belonging network of described PDN GW in the following ways:

If described belonging network information is described APN information of carrying Network Recognition information, then judge that according to described Network Recognition information is whether consistent with the home network network number of described UE described PDN GW belongs to home network or visit net;

If described belonging network information is the network identification mark of described independently PDN, then judge that according to described network identification mark is whether consistent with the home network network number of described UE described PDN GW belongs to home network or visit net;

If described belonging network information is described identification information, then directly judges described PDN GW and belong to home network or visit net according to described identification information.

Further, described UE asks to be its distributing IP address when initiating to adhere to request to described SAE network;

Described SAE network will send to described UE for described UE IP address allocated is included in to adhere in the response, and in the described belonging network information of carrying the PDN GW that distributes into described UE in the response of adhering to.

Further, the mobile management entity MME of described SAE network receives that described UE initiates described adhere to request after, initiate position updating request to home network home subscriber server HSS;

Described HSS is handed down to described MME with the user data of described UE, comprises how described MME distributes PDN GW for UE indication in described user data;

After described MME receives described user data, distribute the PDN GW of home network or the PDN GW of visit net according to the described UE of being designated as in the described user data, and the belonging network information of the PDNGW that will distribute for described UE is included in to adhere to and sends to described UE in the response.

Further, if described UE is not assigned with the IP address in the process that is attached to described SAE network, then described UE is its distributing IP address by the request of dynamic host configuration protocol DHCP mechanism after being attached to described SAE network;

Described SAE network will send to described UE for described UE IP address allocated is included in the dhcp response, and will carry the belonging network information of the PDN GW that distributes into described UE in described dhcp response.

Further, described SIP signaling comprises: the register requirement that described UE initiates when being registered to described IMS network perhaps is being registered to the session invitation request of initiating behind the described IMS network.

Further, described APN APN information of carrying Network Recognition information comprises operator sign OI, promptly comprises network number, country number;

This PDN network identification mark is the network identification mark for the PDN GW of UE distribution.

Further, the belonging network of the network based described PDN GW of described IMS is judged the media routing mode that described UE is current, if described PDN GW belongs to the visit net, then judges the current media routing mode of described UE and produces pattern for visit net this locality.

Further, Proxy Call Session Control Function P-CSCF in the described IMS network, service call conversation control function S-CSCF and application server AS after the register requirement or session invitation request of receiving the belonging network information of carrying described PDN GW that described UE initiates, are preserved the belonging network information of the described PDN GW that wherein carries respectively.

Further, described SAE network is positioned at visit net or home network.

By method provided by the present invention, can solve as IMS and will make a strategic decision the medium route when producing mode switch from visit net this locality and being the home network route pattern, lack whether the basic current UE of judging is the foundation of LBO pattern, thereby cause the problem of making a strategic decision and normally to carry out.

Description of drawings

Fig. 1 is in the prior art, and UE is linked into the configuration diagram of home network IMS domain by the SAE access network under roaming scence;

Fig. 2 is in the prior art, realizes the configuration diagram of LBO pattern by single IP;

Fig. 3 shows in the prior art, and UE is linked into the SAE network, carries out the process that network attachment and IP carrying is set up;

The UE that Fig. 4 shows embodiments of the invention is linked into the SAE network, and network is returned as the process of the belonging network information of the PDN GW that UE distributes;

The UE that Fig. 5 shows embodiments of the invention uses DHCP mechanism to be known as the process of the belonging network information of the PDNGW that UE distributes;

The UE that Fig. 6 shows embodiments of the invention is registered to the IMS network, and the belonging network information of the PDN GW that will distribute for UE is carried the process to the IMS network.

Embodiment

The invention provides a kind of method, in order to realizing that UE is linked into the SAE network under the roaming condition, IMS operation layer (P-CSCF/S-CSCF/AS etc.) is known as the method for the belonging network of the PDN GW that UE distributes, mainly comprises following steps:

(1) under roaming scence, UE is attached to visit net SAE network, and the SAE network is that UE sets up the IP carrying, and is returned as the belonging network information of the PDN GW of UE distribution to UE, promptly this PDN GW belongs to home network and still visits net, and UE is kept at this locality with it after receiving this belonging network information;

(2) UE carries the network to IMS by the SIP signaling with described belonging network information, and network based this belonging network information of IMS judges whether this PDN GW belongs to the visit net.

The media routing mode that UE is current is if then judge the current media routing mode of UE and produce pattern for visit net this locality.

Further, described SIP signaling can comprise: the register requirement that UE initiates when being registered to the IMS network perhaps is being registered to the session invitation request of initiating behind this IMS network.

Further, the SAE network can return to UE by the belonging network information of adhering to the PDN GW that response message or dhcp response message will distribute for this UE.

Fig. 4 is the process of embodiments of the invention, and in order to describe under the roaming scence, UE is linked into the SAE network, and is retrieved as the process of belonging network of the PDN GW of its distribution.The step S401 of this process～S411 and step S414～S418 are identical with existing procedure described in Fig. 3 step S301～S311 and the step S314～S318 respectively, do not repeat them here.The main distinction of the existing procedure that itself and Fig. 3 describe is step S412, S413:

S412, MME send to eNodeB and adhere to response, in this response, are included as the belonging network information of the PDN GW of UE distribution, and promptly which network this PDN GW belongs to particularly;

The belonging network information of the PDN GW that distributes for UE, can adopt following multiple mode to express:

(A) APN information of carrying Network Recognition information, this information comprise operator sign (OI), promptly comprise network number, country number, become the complete description of shape such as APN.MNC.MCC.XXXX.

(B) network identification mark of PDN independently, this PDN network identification mark are the network identification mark of the PDN GW that distributes for UE, and comprising the network No. of this PDN network, country number, shape is as the form of ' MNC.MCC '.

(C) the PDN GW that identification information, this sign clearly are indicated as the UE distribution belongs to home network or visit net.

S413, eNodeB sends voice bearer to UE and sets up request, in this request, carries the IP address information into UE, and is the belonging network information of the PDN GW of UE distribution; Receive the belonging network information of the IP address information of network allocation and PDN GW from eNodeB as UE after, these information are kept at this locality.

If UE receives is the independently network identification mark of PDN of an APN information of carrying Network Recognition information or, UE can number compare the home network network of network of itself and UE, by judging whether to be positioned at home network or visit net with the consistent PDN of identification GW of network number of the home network of UE.That is, if both unanimities, then PDN GW is positioned at home network, otherwise is positioned at the visit net.

Might UE when being attached to the SAE network, be not assigned with the IP address, but ask the SAE network by DHCP (Dynamic Host Configuration Protocol, DHCP) mechanism in follow-up process is its distributing IP address.In this case, also can adopt and use the same method, in the response message of DHCP, not only carry the IP address of UE, also further carry the belonging network information of the PDN GW that distributes into UE, in order to discern the network of this concrete institute of PDN GW subordinate.

Fig. 5 has described UE and has used DHCP mechanism to obtain the flow process of IP address, and in this flow process, network returns to UE by dhcp response with the belonging network attribute of PDN GW.In this flow process, UE is not assigned with the IP address in the process that initially is attached to the SAE network, but the address of the Dynamic Host Configuration Protocol server that network can the distributing IP address in adhering to response returns to UE, and Dynamic Host Configuration Protocol server is served as by PDN GW in this flow process.

S501, UE sends the DHCP request to network, and requiring network is its distributing IP address, and the DHCP request at first is sent to eNodeB/MME;

S502, eNodeB/MME transmits the DHCP request to PDN GW, and PDN GW has served as the role of Dynamic Host Configuration Protocol server, is UE distributing IP address;

S503, PDN GW are UE distributing IP address, return dhcp response, save as the UE IP address allocated in response.Simultaneously, PDN GW comprises the belonging network information of this PDN GW in dhcp response, and this belonging network information can identify the network that this PDN GW is belonged to, and identification method is with described in Fig. 4;

S504, eNodeB/MME transmits dhcp response to UE, does not comprise the belonging network information of this PDN GW if MME finds PDN GW in dhcp response, then can add this information in dhcp response.

Fig. 6 has described after UE is assigned with the IP address, carry out the IMS registration process, pass through registration process, inform the belonging network information of the PDN GW that IMS operation layer (P-CSCF, S-CSCF, HSS, AS) distributes for UE, the IMS operation layer can judge that according to the belonging network information of this PDN GW UE is current whether under the LBO pattern.

S601, UE sends register requirement to P-CSCF, and in this request, UE has carried the belonging network information of the PDN GW that is distributed.

The belonging network information of the PDN GW that distributes for UE, can adopt following multiple mode to express:

(A) APN information of carrying Network Recognition information, this information comprise operator sign (OI), promptly comprise network number, country number, become the complete description of shape such as APN.MNC.MCC.XXXX.

(B) network identification mark of PDN independently, this PDN network identification mark are the network identification mark of the PDN GW that distributes for UE, and comprising the network No. of this PDN network, country number, shape is as the form of ' MNC.MCC '.

(C) identification information, this sign clearly are indicated as PDN GW that UE distributes, and to belong to home network still be the visit net.

S602, P-CSCF receives the register requirement of UE, preserve the information of UE in this locality, and after the belonging network information of the PDN GW that distributes for UE, find the S-CSCF that distributes into UE by I-CSCF, and to S-CSCF transmission register requirement, the belonging network information of wherein carrying the PDN GW that distributes into UE;

S603, S-CSCF receive the register requirement of UE, preserve the information of UE in this locality, and after the belonging network information of the PDN GW that distributes for UE, send user authentication request to HSS, alternatively, in described user authentication request, carry the belonging network information of the PDN GW that distributes into UE;

S604, HSS returns user authentication response to S-CSCF, has comprised authentication and the verify data of UE in the message, i.e. authentication vector;

S605, S-CSCF stores authentication vector, and constructs authentication parameter with authentication vector, initiates the authentication challenge to UE;

S606, UE compute authentication vector returns Authentication Response to S-CSCF;

S607～609, S-CSCF finishes the authentication to UE, searches user data from HSS;

S610～611, if carry out third-party registration, S-CSCF initiates register requirement to third party AS, carries the belonging network information of the PDNGW that distributes into UE in this register requirement; Third party AS finishes the registration of UE;

S612, the registration process success, S-CSCF sends the response of succeeding in registration of 200OK to UE.

In flow process shown in Figure 6, by step S601, S602, S610, the belonging network information of the PDN GW that UE can distribute for UE is sent to network elements such as P-CSCF, S-CSCF, AS by the SIP signaling, and these network elements can be kept at this locality with it.If the belonging network information of this PDN GW is independently PDN identifier of an APN who carries Network Recognition information or, then P-CSCF/S-CSCF/AS can extract network number wherein, compare with the network number of the home network of UE, consistent by judging whether with the home network network number of described UE, just can analyze the PDN GW that distributes for UE and be positioned at home network or be positioned at the visit net, thereby whether can know that UE is current is under the LBO pattern.In addition, if S-CSCF obtains this information, can also be notified to HSS by the IMS registration process, S603 describes as step, and after HSS obtained this information, a part that can be used as user data was preserved, and can be in the follow-up application server AS that needs that offers.

In the SIP signaling, carry the method for the belonging network information of the PDN GW that distributes into UE, can adopt following method:

(a) in field " P-Access-Network-Info " (access network information field), use additional son field.

(b) in field " Contact " (the contact address field of UE), use additional son field.

Certainly, in the SIP signaling, carry the method for the belonging network information of the PDN GW that distributes into UE, also can adopt other field to represent.

After above-mentioned flow performing was finished, the IMS operation layer can be known as the belonging network information of the PDN GW that UE distributes, thereby whether know that UE is current is positioned under the LBO pattern.

Though it is pointed out that the above embodiment of the present invention is the situation that roams into visit ground at UE, method of the present invention also can be applied to the situation of UE at home network, and can not cause the mistake of service logic.

The present invention also has other multiple different embodiment, for example, UE does not inform that by the IMS registration process IMS operation layer is the belonging network information of the PDN GW of UE distribution, but by carrying this belonging network information in the signaling of when calling out, initiating such as SIP such as INVITE request grade, as the SIP header or therein in order to describe SDP (the Session Description Protocol of media negotiation form, Session Description Protocol) carry in the information, its basic principle is with identical by the IMS registration process.

Claims (9)

1. an IMS is known as the method for the belonging network of the PDN GW that UE distributes, it is characterized in that, may further comprise the steps:

User equipment (UE) is attached to System Architecture Evolution SAE network, described SAE network is that described UE sets up the IP carrying, and being returned as the belonging network information of the packet data network gateway PDN GW that UE distributes to described UE, described UE is kept at this locality after receiving the belonging network information of described PDN GW;

Described UE carries the network to IP Multimedia System IMS by Session initiation Protocol SIP signaling with the belonging network information of described PDN GW, and the belonging network information of the network based described PDN GW of described IMS is judged the belonging network of described PDN GW;

Wherein, the belonging network information of described PDN GW is: carry the APN APN information of Network Recognition information or independently PDN network identification mark or be indicated as the identification information that PDN GW that UE distributes belongs to home network or visit net;

The network based described belonging network information of described IMS is judged the belonging network of described PDN GW in the following ways:

If described belonging network information is described APN information of carrying Network Recognition information, then judge that according to described Network Recognition information is whether consistent with the home network network number of described UE described PDN GW belongs to home network or visit net;

If described belonging network information is the network identification mark of described independently PDN, then judge that according to described network identification mark is whether consistent with the home network network number of described UE described PDN GW belongs to home network or visit net;

If described belonging network information is described identification information, then directly judges described PDN GW and belong to home network or visit net according to described identification information.

2. the method for claim 1 is characterized in that,

Described UE asks to be its distributing IP address when initiating to adhere to request to described SAE network;

Described SAE network will send to described UE for described UE IP address allocated is included in to adhere in the response, and in the described belonging network information of carrying the PDN GW that distributes into described UE in the response of adhering to.

3. method as claimed in claim 2 is characterized in that,

The mobile management entity MME of described SAE network receives that described UE initiates described adhere to request after, initiate position updating request to home network home subscriber server HSS;

Described HSS is handed down to described MME with the user data of described UE, comprises how described MME distributes PDN GW for UE indication in described user data;

After described MME receives described user data, distribute the PDN GW of home network or the PDN GW of visit net according to the described UE of being designated as in the described user data, and the belonging network information of the PDNGW that will distribute for described UE is included in to adhere to and sends to described UE in the response.

4. method as claimed in claim 3 is characterized in that,

If described UE is not assigned with the IP address in the process that is attached to described SAE network, then described UE is its distributing IP address by the request of dynamic host configuration protocol DHCP mechanism after being attached to described SAE network;

Described SAE network will send to described UE for described UE IP address allocated is included in the dhcp response, and will carry the belonging network information of the PDN GW that distributes into described UE in described dhcp response.

5. as each described method of claim 1 to 4, it is characterized in that,

Described SIP signaling comprises: the register requirement that described UE initiates when being registered to described IMS network perhaps is being registered to the session invitation request of initiating behind the described IMS network.

6. method as claimed in claim 5 is characterized in that,

Described APN APN information of carrying Network Recognition information comprises operator sign OI, promptly comprises network number, country number;

This PDN network identification mark is the network identification mark for the PDN GW of UE distribution.

7. as claim 1 or 6 described methods, it is characterized in that,

The belonging network of the network based described PDN GW of described IMS is judged the media routing mode that described UE is current, if described PDN GW belongs to the visit net, then judges the current media routing mode of described UE and produces pattern for visit net this locality.

8. method as claimed in claim 5 is characterized in that,

Proxy Call Session Control Function P-CSCF in the described IMS network, service call conversation control function S-CSCF and application server AS after the register requirement or session invitation request of receiving the belonging network information of carrying described PDNGW that described UE initiates, are preserved the belonging network information of the described PDN GW that wherein carries respectively.

9. the method for claim 1 is characterized in that,

Described SAE network is positioned at visit net or home network.

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