CN102111835B

CN102111835B - Method and device for processing non-access stratum message in handover process of network evolution

Info

Publication number: CN102111835B
Application number: CN2011100513189A
Authority: CN
Inventors: 张宏卓; 邱勇; 黄英; 王强
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2007-08-13
Filing date: 2007-11-29
Publication date: 2012-11-07
Anticipated expiration: 2027-11-29
Also published as: CN102111835A

Abstract

The invention provides a method for processing a non-access stratum (NAS) message in the handover process of network evolution, which comprises the following steps that: a source eNodeB (S-eNB) receives a direct-transfer message sent by a mobility management entity (MME) in an evolved packet core (EPC), wherein the direct-transfer message carries the NAS message sent to user equipment (UE) by the MME in the EPC; and the S-eNB sends a direct-transfer failure message or a direct-transfer response message to the MME in the EPC, wherein the direct-transfer failure message or the direct-transfer response message carries a cause value and the NAS message which is sent to the UE unsuccessfully and received from the MME in the EPC. In the method for processing the NAS message in the handover process of the network evolution, the S-eNB informs the MME in the EPC of the NAS message sent to the UE unsuccessfully by the S-eNB, so the MME in the EPC only needs to buffer the NAS message when the NAS message fails in transmission, and the consumption of a memory space of the EPC is reduced.

Description

The processing method of non-access layer information and device in the handoff procedure in the evolvement network

The present invention be submitted that Patent Office of the People's Republic of China, application number are 200710194669.9 on November 29th, 2007, denomination of invention is the division of the one Chinese patent application of " in the evolvement network in the handoff procedure processing method of non-access layer information and device ", requiring to submit on August 13rd, 2007 Patent Office of the People's Republic of China, application number is that to submit Patent Office of the People's Republic of China, application number on August 23rd, 200710140567.9 and 2007 be the priority of two patent applications of 200710147031.X.

Technical field

The present invention relates to the communications field, particularly Non-Access Stratum (NonAccess Stratum, NAS) processing method of message and device in the handoff procedure in the evolvement network.

Background technology

UMTS (Universal Mobile Telecommunications System; UMTS) be to adopt WCDMA to insert (Wideband Code Division Multiple Access; WCDMA) 3-G (Generation Three mobile communication system) of air interface technologies also calls the WCDMA communication system to the UMTS system usually.

UMTS has adopted and the similar structure of second generation GSM, comprise Radio Access Network (Radio Access Network, RAN), core network (Core Network, CN) and subscriber equipment (User Equipment, UE).Wherein RAN is used to handle all and wireless function associated; All voice calls are connected with data in the UMTS and CN handles; And the exchange of realization and external network and routing function; RAN in the UMTS system be land radio access web (UMTS TerritorialRadio Access Network, UTRAN).

Fig. 1 is the structural representation of UMTS; Wherein UTRAN comprises one and several RNSs (Radio Network Subsystem; RNS), (Radio Network Controller RNC) forms with one or more base stations (NodeB) each RNS by a radio network controller.RNC is connected with CN through the lu interface, and NodeB is connected through the lub interface with RNC, and interconnected through the lur interface between the RNC.RNC is used for distributing and is attached thereto with control or the Radio Resource of relevant NodeB, and NodeB then accomplishes the data flow conversion between lub interface and the Uu interface, and the while is also participated in a part of RRM.

The network architecture shown in Figure 1 is based on the 3GPP Re16 framework of version in the past; Consider the competitiveness of future network; 3GPP is studying a kind of brand-new evolution network framework to satisfy following mobile network's application demand; Comprise System Architecture Evolution (System Architecture Evolvement; SAE) and the Long Term Evolution of Access Network (Long Time Evolvement, LTE), the target of network evolution is to be desirable to provide a kind of low time delay, high data rate, high power system capacity and covering, low cost, IP-based network fully.

Fig. 2 is the evolution network framework sketch map, comprise in this network architecture UE, evolution land radio access web (Evolved UMTS Territorial Radio Access Network, E-UTRAN) and evolution block core (Evolved Packet Core, EPC).E-UTRAN is made up of evolution base station (eNodeB), connects through X2 interface between the eNodeB.Comprise among the EPC: mobile management entity (MobilityManagement Entity, MME), service SAE gateway (Serving SAE Gateway) and packet data network SAE gateway (Packet Date Network SAE Gateway).Wherein, MME is responsible for the mobile management of chain of command; Comprise the management of user's context and mobile status, distributing user temporary identity sign etc., be connected through the S3 interface, be connected through S1-MME interface with E-UTRAN with SGSN in the existing network; Be connected through S1-U interface with service SAE gateway, be provided with timer among the MME; Service SAE gateway is responsible for initiating paging for downlink data under the idle condition, and IP bearing parameter and the interior routing iinformation of network etc. are preserved in management; PDN SAE gateway then serves as the user plane anchor point between different access systems.Also comprised in the system shown in Figure 2 "Policy and Charging Rules Function entity (Policy andCharging Rule Function, PCRF) and home network server (Home Subscriber Server, HSS).

In the evolution network framework; There is the switching of X2 interface between the eNodeB; With the base station at the current place of UE be called the source evolution base station (Source eNodeB, S-eNB), with UE to switch to the base station be called purpose evolution base station (Target eNodeB; T-eNB), above-mentioned switching refers to, and to be exactly UE switch to the process the sub-district of T-eNB control from S-eNB.

Fig. 3 is the switching flow sketch map of X2 interface in the prior art evolvement network, and the step in this flow process comprises:

0) the UE context in the S-eNB includes the roaming restricted information, these information when connection is set up or the last time tracking area (Tracking Area is provided when TA) upgrading.

1) (the S-eNB decision switches to UE in the sub-district by T-eNB control for Radio ResourceManagement, RRM) information according to the measurement result of UE and the RRM of S-eNB.

2) S-eNB sends a handoff request (HANDOVER REQUEST) message to T-eNB; Transmit target side in the message and switch the necessary information when preparing, comprising: UE is in the X2 of S-eNB signaling context reference, and UE is in the context reference of the EPC of S1 interface signaling; Target Cell Identifier; Radio resource control (Radio Resource Control, RRC) context, SAE bearer context.T-eNB connects with reference to coming addressing S-eNB and EPC with the S1/X2 signaling of UE.The SAE bearer context comprises the address information of necessary wireless network layer and transport network layer, the service quality general picture that SAE carries, and possible access layer configuration information.The resource that the T-eNB configuration needs.

3) T-eNB accomplishes access control to improve the possibility of handover success according to the SAE bearer quality of service general picture of receiving.If T-eNB can satisfy the resource requirement that SAE carries; Then distribute respective resources according to the SAE bearer quality of service general picture of receiving; Reserve simultaneously cell-radio network temporary identity sign (Cell Radio Network Temporary Idetifier, C-RNTI).

4) T-eNB sends handoff request to S-eNB and replys (HANDOVER REQUESTACKNOLEDGE) message; Comprise newly assigned C-RNTI in the message; And possible parameter; Like access parameter, set up to transmit the wireless network layer used in the tunnel (Radio Network Level, RNL) and/or transport network layer (Transfer Network Level, TNL) information etc.

5) UE receives switching command (HANDOVER COMMAND) message that S-eNB sends, and this information order UE accomplishes handoff procedure.Comprise newly assigned C-RNTI in the message, the possible time started etc.

6) in a single day successfully insert Target cell, UE sends switching affirmation (HANDOVERCONFIRM) message to T-eNB and representes to switch completion, whether the C-RNTI in this message of T-eNB inspection is distributed by oneself.

7) T-eNB send to switch accomplishes (HANDOVER COMPLETE) message to EPC, and notice UE is changing district more, and EPC switches to T-eNB with data path, and discharges the relevant user plane of S-eNB and the resource of transport network layer.

8) EPC sends to switch to accomplish to T-eNB and replys (HANDOVER COMPLETE ACK) message, confirms to switch and accomplishes.

9) T-eNB sends resource release (RELEASE RESOURCE) message to S-eNB, triggers S-eNB and discharges resource.

10) receive resource release message after, S-eNB discharges and the resource of context-sensitive Radio Resource of UE and chain of command.

In practical application, EPC need send NAS message to UE through evolution base station, to realize the business of corresponding UE, sends the moment and the blanking time of NAS message, and is different according to different service.

Handle the scheme of NAS message when having at present two kinds of handover success to above-mentioned X2 interface.Fig. 4 shows the schematic flow sheet of first kind of scheme, and this flow process comprises:

Step 401:UE receives the switching command that S-eNB sends.

Step 402:S-eNB receives the direct-sending message from EPC, carries the NAS message that mails to UE in this direct-sending message.

Step 403:S-eNB judgement UE just in handoff procedure, then sends the failed message that direct transfers to EPC, and carries suitable cause value.

Step 404:EPC suspends the message to UE transmission NAS.

Step 405:UE sends switch acknowledgment message to T-eNB, the expression handover success.

Step 406:T-eNB sends handoff completion message to EPC.

Step 407: when UE sent NAS message, EPC sent to T-eNB and carries the direct-sending message of NAS message at needs.

Step 408:T-eNB gives UE through downstream message with the NAS forwards.

Through above-mentioned steps 401～step 408, when can be implemented in handover success, EPC correctly sends NAS message to UE.

Fig. 5 shows the schematic flow sheet of second kind of scheme, and this flow process comprises:

Step 501:UE receives the switching command that S-eNB sends.

Step 502:S-eNB receives the NAS message that EPC mails to UE.

Step 503:S-eNB judges that UE switches, and the T-eNB that switches to UE transmits the NAS message that receives.

Step 504:UE sends switch acknowledgment message to T-eNB.

After step 505:UE switches completion, T-eNB will send to UE from the NAS message that S-eNB receives.

Through above-mentioned steps 501～step 505, can in the UE handoff procedure, NAS message be forwarded to T-eNB earlier from S-eNB, behind the UE handover success, NAS message is being sent to UE by T-eNB.

And when the handoff failure, how EPC handles the NAS message that sends to UE, does not also have clear and definite scheme at present.

There is a kind of refusal re-transmission scheme that utilizes retransmission timer to realize, but also do not provide the clear and definite scheme of using retransmission timer in the prior art.

It is thus clear that, the processing scheme of prior art NAS message, in handoff procedure failure, when promptly UE came back in the coverage of S-eNB, EPC can't in time be notified, can't be correct NAS message is sent to UE; In the scheme of retransmission timer is arranged, do not provide concrete implementation method yet.In addition, the forwarding scheme of passing through X2 interface that provides during handover success in the prior art does not provide concrete forwarding implementation.

Summary of the invention

One aspect of the present invention provides in a kind of evolvement network the processing method of non-access layer information in the handoff procedure; Comprise: source evolution base station S-eNB receives the direct-sending message that the mobile management entity MME among the evolution block core EPC is sent, and carries the non access stratum NAS message that MME among the above-mentioned EPC issues user equipment (UE) in this direct-sending message; The MME of above-mentioned S-eNB in above-mentioned EPC sends the direct transfer failed message or the response message that direct transfers, and that carries in this direct transfer failed message or the response message that direct transfers that cause value and the MME from above-mentioned EPC receive sends successful NAS message to above-mentioned UE.

The present invention provides a kind of evolution base station eNB on the other hand; Comprise: Transmit-Receive Unit; Be used for receiving the direct-sending message that the mobile management entity MME of evolution block core EPC is sent, carry the non access stratum NAS message that MME among the above-mentioned EPC issues user equipment (UE) in this direct-sending message; Also be used for sending the direct transfer failed message or the response message that direct transfers to the MME of above-mentioned EPC, that carries in this direct transfer failed message or the response message that direct transfers that cause value and the MME from above-mentioned EPC receive sends successful NAS message to above-mentioned UE.

Further aspect of the present invention provides the mobile management entity in a kind of mobile management core; Comprise: Transmit-Receive Unit; Be used for sending direct-sending message, carry the non access stratum NAS message that MME among the above-mentioned EPC issues user equipment (UE) in the above-mentioned direct-sending message to evolution base station eNB; Also be used to receive the direct transfer failed message or the response message that direct transfers that above-mentioned eNB sends, that carries in this direct transfer failed message or the response message that direct transfers that cause value and the MME from above-mentioned EPC receive sends successful NAS message to above-mentioned UE.

Further aspect of the present invention also provides a kind of evolvement network, comprises aforesaid eNB and aforesaid mobile management entity.

It is thus clear that; The processing method of NAS message and device in the handoff procedure in the evolvement network that the embodiment of the invention provides; S-eNB informs that carrying S-eNB in the message that the EPC current UE switching sends successful NAS message to UE; Thereby EPC only need be when NAS message transmits failure this NAS message of buffer memory, reduced the consumption of EPC memory space.

Description of drawings

Fig. 1 is a UMTS system configuration sketch map;

Fig. 2 is an evolvement network framework sketch map;

Fig. 3 is based on the switching flow sketch map of X2 interface in the prior art evolvement network;

Fig. 4 is the process flow sketch map of first kind of NAS message during handover success in the prior art evolvement network;

Fig. 5 is the process flow sketch map of second kind of NAS message during handover success in the prior art evolvement network;

Fig. 6 is the process flow sketch map of first kind of NAS message in the handoff procedure in the embodiment of the invention evolvement network;

Fig. 7 is first kind of preferred embodiments schematic flow sheet of flow process shown in Figure 6;

Fig. 8 is second kind of preferred embodiments schematic flow sheet of flow process shown in Figure 6;

Schematic flow sheet during handover success that Fig. 9 further comprises for flow process shown in Figure 6;

Figure 10 is the process flow sketch map of second kind of NAS message in the handoff procedure in the embodiment of the invention evolvement network;

Figure 11 is the preferred embodiments schematic flow sheet of flow process shown in Figure 10;

Figure 12 is the retransmission method schematic flow sheet of NAS message in the handoff procedure in the embodiment of the invention evolvement network;

Figure 13 is the schematic flow sheet of first kind of preferred embodiments of flow process shown in Figure 12;

Figure 14 is the schematic flow sheet of second kind of preferred embodiments of flow process shown in Figure 12;

Figure 15 can also receive the schematic flow sheet that S-eNB uses the NAS message of tunnel transmission for T-eNB in the flow process shown in Figure 12;

Figure 16 is the schematic flow sheet of first kind of preferred embodiments of flow process shown in Figure 15;

Figure 17 is the schematic flow sheet of second kind of preferred embodiments of flow process shown in Figure 15;

Figure 18 is sent to NAS message by S-eNB first kind of preferred embodiments schematic flow sheet of UE during for flow process handoff failure shown in Figure 15;

Figure 19 is sent to NAS message by S-eNB second kind of preferred embodiments schematic flow sheet of UE during for flow process handoff failure shown in Figure 15;

Figure 20 is the MME structural representation among first kind of EPC of the embodiment of the invention;

Figure 21 is the MME structural representation among first kind of EPC of the embodiment of the invention;

Figure 22 is the structural representation of first kind of evolution base station of the embodiment of the invention;

Figure 23 is the structural representation of second kind of evolution base station of the embodiment of the invention;

Figure 24 is the structural representation of the third evolution base station of the embodiment of the invention.

Embodiment

For the purpose, the advantage that make the embodiment of the invention is clearer, the embodiment of the invention is done detailed explanation below in conjunction with accompanying drawing.

At first, introduce in the embodiment of the invention evolvement network processing method of NAS message in the handoff procedure, said method comprises two kinds.

Fig. 6 is the process flow sketch map of first kind of NAS message in the handoff procedure in the embodiment of the invention evolvement network, and this flow process comprises:

The message that the UE that step 601:EPC reception S-eNB sends is switching, the NAS message that buffer memory sends to UE.

In this step; The message that EPC receives the S-eNB transmission can comprise before: EPC sends direct-sending message to S-eNB; Carry the NAS message that sends to UE in this direct-sending message; In this case; Message that S-eNB sends can be the direct transfer failed message or the response message that direct transfers, and can carry cause value in this direct transfer failed message or the response message that direct transfers, and is switching like UE etc.; Can also carry the NAS message that S-eNB receives from EPC in this direct transfer failed message or the response message that direct transfers. this NAS message can be the NAS message that before UE sends switching command, receives from EPC at S-eNB, also can be the NAS message that after UE sends switching command, receives from EPC at S-eNB; Perhaps, S-eNB is after sending switching command to UE, and EPC does not send NAS message, and S-eNB directly sends handoff notification message to EPC, and EPC knows directly that in this case UE switches.

If handoff failure, UE return the S-eNB coverage, S-eNB sends to EPC with the message that UE returns self coverage.

Step 602: if handoff failure, the UE that EPC reception S-eNB sends returns the message of S-eNB coverage,

Step 603: when UE sent NAS message, EPC sent NAS message through S-eNB to UE at needs.

In this step, after EPC knows that in step 602 current UE is returned the S-eNB coverage, when UE sends NAS message, send NAS message to UE through S-eNB at needs.The method of sending can for: EPC sends to S-eNB and carries the direct-sending message that EPC issues the NAS message of UE, and (Radio Resource Control, RRC) the descending direct-sending message of message sends to UE with NAS message to S-eNB through radio resource control again.

Through step 601～step 603, the process flow of first kind of NAS message end in the handoff procedure in the embodiment of the invention evolvement network, this flow process is that S-eNB sends switching command to UE, promptly switches the processing method of beginning back NAS message.

In handoff procedure; Involved concrete reciprocal process is sent handoff request and T-eNB carries out access control etc. like S-eNB to T-eNB, is those skilled in the art's common practise; In embodiment of the invention said method and subsequent descriptions, all repeat no more.

The processing method of first kind of NAS message in the handoff procedure in the embodiment of the invention evolvement network; When handoff failure; EPC receives the message that UE that S-eNB sends returns the S-eNB coverage because EPC is known the definite position of current UE, at needs when UE sends NAS message; Can send NAS message to UE through S-eNB, correctly send NAS message to UE when having realized handoff failure.

Fig. 7 is the schematic flow sheet of first kind of preferred embodiments of flow process shown in Figure 6, and this flow process illustrates S-eNB and sends switching command to UE, to the complete procedure of switching beginning back NAS Message Processing.Flow process shown in Figure 7 comprises:

Step 701:UE receives the switching command message that S-eNB sends, and this information order UE accomplishes handoff procedure.

Step 702:EPC sends direct-sending message to S-eNB, carries the NAS message that sends to UE in this direct-sending message.

Step 703:S-eNB finds that UE not in the coverage of self, sends the direct transfer failed message or the response message that direct transfers to EPC, carries cause value in the message, and for example UE is switching etc.; Can also carry the NAS message that S-eNB receives from EPC in this direct transfer failed message or the response message that direct transfers. this NAS message can receive from EPC before UE sends switching command at S-eNB, also can after UE sends switching command, receive from EPC at S-eNB.

After step 704:EPC receives the direct transfer failed message or the response message that direct transfers, the NAS message that buffer memory sends.

Step 705:S-eNB detects handoff failure, or detects other abnormal conditions.

Step 706:S-eNB initiates the handover cancelling flow process to T-eNB.

Step 707:S-eNB sends the message that comprises the UE current location to EPC, informs that promptly UE returns the S-eNB coverage.

Step 708: when UE sent NAS message, EPC sent to the NAS message of UE to S-eNB at needs.

Step 709:S-eNB utilizes the descending direct-sending message of RRC message to give UE with the NAS forwards that EPC sends.

Above-mentioned steps 702 can take place before step 701. and be that step 701 and step 702 do not have strict execution sequence relation.

Above-mentioned steps 706 can be optional step, promptly can not comprise step 706 in this preferred embodiments.Comprising under the situation of step 706 that step 706 and step 707 do not have strict execution sequence relation.

In the above-mentioned steps 707, S-eNB can utilize existing S1 interface message to the message that comprises the UE current location that EPC sends, and also can be a new message, informs that the EPC current UE returned the S-eNB coverage as long as can accomplish.Table one has provided a kind of form of above-mentioned message.

Cell/group name		The type reference	Denotational description
				Type of message	Essential
The identify label of MME applying portion agreement	Essential	The integer character constant string	The receiving terminal of Indication message
				The evolution base station identify label	Essential	The integer character constant string	The evolution base station self identification
Reason	Optional	Integer is enumerated	Cause value

Table one

In this preferred embodiment, S-eNB sends the message that comprises the UE current location to EPC, makes EPC when handoff failure, can correctly know the position of UE.

Fig. 8 is the schematic flow sheet of second kind of preferred embodiments of flow process shown in Figure 6, and this flow process illustrates from initiating switching, to the complete process of switching beginning back NAS Message Processing.Flow process shown in Figure 8 comprises:

Step 801 is identical with step 701.

Step 802:S-eNB sends handoff notification message to EPC, and notice EPC current UE switches.

After step 803:EPC receives handoff notification message, the NAS message that buffer memory sends.

Step 804～step 808 is identical with step 705～step 709 respectively.

Identical with first kind of preferred embodiments, step 805 is that S-eNB also is optional step to T-eNB initiation handover cancelling flow process, and the execution sequence of step 805 and step 806 does not have strict regulations.

And in step 806, the same with step 707, S-eNB can utilize existing S1 interface message to the message that comprises the UE current location that EPC sends, and also can be a new message, informs that the EPC current UE returned the S-eNB coverage as long as can accomplish.The form of message also can be shown in table one.

In step 802, S-eNB can have multiple form to the handoff notification message that EPC sends, and table two has provided a kind of concrete form of above-mentioned handoff notification message.

Table two

The difference of above-mentioned flow process shown in Figure 8 and flow process shown in Figure 7 comprises: in flow process shown in Figure 8; S-eNB adopts directly and notifies UE just in switching way to EPC; Rather than after EPC sends direct-sending message, switch with the response message notice UE that direct transfers behind the failed message that direct transfers again.Thereby when the handoff failure, inform the position of EPC current UE with direct mode,, inform that through direct transfer failed message or the response message that direct transfers that return to EPC the position of EPC current UE is easier again than receiving the main message that passes that EPC sends earlier.

In the flow process shown in Figure 6, the handling process when can further include handover success, the complete process flow when Fig. 9 shows this handover success, this flow process comprises:

Step 901～step 903 is identical with step 801～step 803.

Step 904:UE sends switch acknowledgment message to T-eNB, and completion is switched in expression.

Step 905:T-eNB sends handoff completion message to EPC, and notice EPC UE has accomplished switching.

Step 906: when UE sent NAS message, EPC sent direct-sending message to T-eNB at needs, had carried the NAS message of issuing UE in this direct-sending message.

Step 907:T-eNB utilizes the descending direct-sending message of RRC will issue the NAS message of UE, sends to UE.

With respect to the situation of handoff failure, during above-mentioned handover success, send handoff completion message to EPC by T-eNB, be equivalent to inform that the EPC current UE has got into the T-eNB coverage, make EPC send NAS message to UE through T-eNB.

What more than introduce is in the processing method of first kind of NAS message when switching in the embodiment of the invention evolvement network, the flow process of two kinds of preferred embodiments.

Figure 10 is the process flow sketch map of second kind of NAS message in the handoff procedure in the embodiment of the invention evolvement network, and this flow process comprises:

The message that the UE that step 1001:EPC reception S-eNB sends is switching starts retransmission timer.

In this step; The message that EPC receives the S-eNB transmission can comprise before: EPC sends direct-sending message to S-eNB, carries the NAS message that sends to UE in this direct-sending message, in this case; The message that S-eNB sends can for: the failed message or the response message that direct transfers direct transfer; Can carry cause value in this direct transfer failed message or the response message that direct transfers, switch etc., can also carry the NAS message that S-eNB receives from EPC in this direct transfer failed message or the response message that direct transfers like UE.This NAS message can receive from EPC before UE sends switching command at S-eNB, also can after UE sends switching command, receive from EPC at S-eNB.

EPC receive message that S-eNB sends can also for: need not to send under the situation of direct-sending message at EPC, the handoff notification message that the S-eNB of reception directly sends, EPC knows directly that in this case UE switches.In this step, the retransmission timer of startup can (S1 Application Part, S1-AP) retransmission timer also can be other retransmission timer for S1 Application of Interface part agreement.

Step 1002: if handover success, EPC receives the handoff completion message that T-eNB sends, and stops retransmission timer, when UE sends NAS message, sends NAS message through T-eNB to UE at needs.

Step 1003: if handoff failure, after retransmission timer was overtime, when UE sent NAS message, EPC sent NAS message through S-eNB to UE at needs.

In this step, after retransmission timer was overtime, EPC did not receive the message of UE handover success, thought that then UE still is in the S-eNB coverage, in this case, when needs when UE sends NAS message, EPC can send NAS message to UE through S-eNB.The method of sending can for: EPC sends to S-eNB and carries the direct-sending message of the NAS message of issuing UE, and S-eNB through the descending direct-sending message of RRC message, sends to UE with NAS message again.

The processing method of second kind of NAS message in the handoff procedure is provided with retransmission timer, during handoff failure in the embodiment of the invention evolvement network in EPC; EPC can when UE sends NAS message, correctly send NAS message to UE at needs after retransmission timer is overtime; During handover success; EPC stops retransmission timer after receiving handoff completion message, and sends NAS message through T-eNB.

In the above-mentioned steps 1001; In the message that the UE that EPC receives is switching; Can also carry temporal information, if the time between S-eNB and EPC is synchronous, then this temporal information can be S-eNB sends the moment from switching command to UE; Or S-eNB receives the moment of direct-sending message, or the failed message that direct transfers moment of replying etc.; If the time between S-eNB and EPC is asynchronous, then this temporal information can be that S-eNB sends switching command and receives the time interval between the direct-sending message to UE.In this case, in the step 1001, can confirm the length of retransmission timer earlier according to temporal information, restart retransmission timer, thereby determine the length of retransmission timer accurately.

The processing method of second kind of NAS message in the handoff procedure provides a kind of preferred embodiments in the embodiment of the invention evolvement network, and Figure 11 shows the preferred embodiments flow process of flow process shown in Figure 10, the handling process when this flow process is handoff failure, and this flow process comprises:

Step 1101:UE receives the switching command message that S-eNB sends, and this information order UE accomplishes handoff procedure.

Step 1102:EPC sends direct-sending message to S-eNB, carries the NAS message of issuing UE in this direct-sending message.

Step 1103:S-eNB discovery UE not in the coverage of self, sends the direct transfer failed message or the response message that direct transfers to EPC, carries cause value and temporal information in this direct transfer failed message or the response message that direct transfers.Can also carry the NAS message that S-eNB receives from EPC in this direct transfer failed message or the response message that direct transfers. this NAS message can receive from EPC before UE sends switching command at S-eNB, also can after UE sends switching command, receive from EPC at S-eNB.Step 1104: if life period information in the message; The time span switched according to direct transfer temporal information in the failed message or the response message that direct transfers and the UE that utilizes empirical value to confirm of EPC then; Confirm the length of retransmission timer, start retransmission timer, suspend and send NAS message.

Step 1105:S-eNB detects handoff failure, or detects other abnormal conditions.

Step 1106:S-eNB initiates the handover cancelling flow process to T-eNB.

Retransmission timer among the step 1107:EPC is overtime.

Step 1108: when UE sent NAS message, EPC sent direct-sending message to S-eNB at needs, carried the NAS message of issuing UE in this direct-sending message.

Step 1109:S-eNB utilizes the descending direct-sending message of RRC message that NAS message is sent to UE.

Above-mentioned steps 1102 can take place before step 1101.Be that step 1101 and step 1102 do not have strict execution sequence

Above-mentioned steps 1106 is an optional step, and step 1106 and step 1107～step 1108 do not have strict execution sequence.

In step 1103, S-eNB has not only carried cause value in the direct transfer failed message or the response message that direct transfers that EPC sends, also carried temporal information, and table three has provided a kind of message format of this direct transfer failed message or the response message that direct transfers.

Cell/group name		The type reference	Denotational description
				Type of message	Essential
The identify label of MME applying portion agreement	Essential	The integer character constant string	The receiving terminal of Indication message
				The evolution base station identify label	Optional	The integer character constant string	The sign of evolution base station self
Reason	Optional	Integer is enumerated	Cause value
				Temporal information	Essential	The integer character constant string	Temporal information
Timestamp	Optional	The integer character constant string	Timestamp
				The time interval	Optional	Integer	The time interval

Table three

In above-mentioned flow process shown in Figure 11; Also can be after UE begins to switch; Directly switch by S-eNB, and after needn't waiting S-eNB to receive the direct-sending message that EPC sends, inform that through the direct transfer failed message or the response message that direct transfers the EPC current UE switches again to EPC announcement current UE.Can make process simplification like this.

Secondly, introduce in the embodiment of the invention evolvement network retransmission method of NAS message in the handoff procedure.

Figure 12 is the retransmission method schematic flow sheet of NAS message in the handoff procedure in the embodiment of the invention evolvement network, and this flow process comprises:

Step 1201:S-eNB receives the NAS message that EPC sends.This NAS message can receive from EPC before UE sends switching command message at S-eNB, also can after UE sends switching command message, receive from EPC at S-eNB.

Step 1202:T-eNB receives the NAS message that S-eNB uses X2 interface control protocol message or tunnel to send.S-eNB can be carried at this NAS message in the RRC message and send, and like the descending direct-sending message of RRC, can also directly send.

Step 1203: if handoff failure, S-eNB sends to UE with said NAS message.

Step 1204: if handover success, T-eNB sends to UE with said NAS message.

The retransmission method of NAS message in the handoff procedure in the embodiment of the invention evolvement network; Can use X2 interface control protocol message bearing NAS message; And pass through the X2 interface control messages and between S-eNB and T-eNB, transmit NAS message; Also can transmit NAS message through the tunnel between S-eNB and the T-eNB, transmitting at X2 interface for NAS message provides concrete implementation.

Above-mentioned X2 interface control protocol message; Different selection modes can be arranged; Be example with X2-AP control protocol message and GTP-C control protocol message respectively below, provide in first kind of evolvement network of the embodiment of the invention two kinds of preferred embodiments of the retransmission method of NAS message in the handoff procedure.

Figure 13 is the schematic flow sheet of first kind of preferred embodiments of flow process shown in Figure 12, and this flow process comprises:

Step 1301:UE receives the switching command message that S-eNB sends, and this information order UE accomplishes handoff procedure.

Step 1302:EPC sends descending direct-sending message to S-eNB, carries the NAS message that will issue UE in this descending direct-sending message.

Step 1303:S-eNB sends the said NAS message receive to T-eNB, and the concrete grammar of transmission does, the NAS message bearing in X2-AP control protocol message, is sent to T-eNB with the form of cell.This NAS message can be carried in the RRC message and forward, and like the descending direct-sending message of RRC, can also directly forward.

Step 1304:UE sends switch acknowledgment message to T-eNB.

Step 1305:T-eNB sends handover success message to EPC, and notice EPC UE has accomplished switching.

Step 1306:EPC sends to switch to T-eNB and accomplishes response message, confirms to switch and accomplishes.

Step 1307:T-eNB utilizes the descending direct-sending message of RRC message, and NAS message is sent to UE.

In the flow process shown in Figure 13, step 1302 also can be carried out before step 1301.

In the flow process shown in Figure 13, step 1307 also can be in step 1304, or carries out at once after the step 1305.

X2-AP control protocol message in the step 1303 can be the special application layer messages that increases on X2 interface, and table four has provided a kind of message structure of this message.

Cell/group name		The type reference	Denotational description
				Type of message	Essential
The S-eNB identify label	Essential		The receiving terminal of Indication message
				The T-eNB identify label	Essential	Self identification
NAS message	Essential	Character string	The NAS message of transmitting

Table four

Figure 14 is the schematic flow sheet of second kind of preferred embodiments of flow process shown in Figure 12, and this flow process comprises:

Step 1401～step 1402 is identical with step 1301～step 1302, and step 1404～step 1407 is also identical with step 1304～step 1307.

Flow process shown in Figure 14 and flow process shown in Figure 13, difference be, in the step 1403 of Figure 14, S-eNB sends the said NAS message that receives to T-eNB, and the concrete grammar of transmission does, with the NAS message bearing in GTP-C control protocol message.This NAS message can be carried in the RRC message and forward, and like the descending direct-sending message of RRC, can also directly transmit.

Above-mentioned GTP-C control protocol message can be the special user plane messages that increases on X2 interface, and table five has provided a kind of message format of this message.

Cell/group name		The type reference	Denotational description
				Type of message	Essential	The sign of newly-increased GTP-C message.
NAS message	Essential	String of binary characters	The NAS message of transmitting

Table five

In the flow process shown in Figure 12, T-eNB can also receive the NAS message that S-eNB uses the tunnel to send, and Figure 15 can also receive the schematic flow sheet that S-eNB uses the NAS message of tunnel transmission for T-eNB in the flow process shown in Figure 12, and this flow process comprises:

Step 1501:T-eNB sets up the tunnel from S-eNB to T-eNB to user plane IP address and Tunnel End Point Identifier that S-eNB sends corresponding T-eNB.

Step 1502:T-eNB receives the NAS message that S-eNB sends through the tunnel of said foundation.This NAS message can be carried in the RRC message and transmit, and like the descending direct-sending message of RRC, can also directly transmit.

Step 1503: if handover success, T-eNB sends to UE with NAS message.

The tunnel of above-mentioned foundation can be to be specifically designed to the dedicated tunnel of transmitting NAS message; Also can be to use the tunnel of transmitting user data to share forwarding NAS message; When difference just is to set up the tunnel; The Tunnel End Point Identifier that S-eNB sends to T-eNB is a Tunnel End Point Identifier of transmitting NAS message, or the Tunnel End Point Identifier of user data transmission, just can set up different tunnels respectively according to different Tunnel End Point Identifiers.Be example with these two kinds of tunnels respectively below, introduce in second kind of evolvement network of the embodiment of the invention two kinds of preferred embodiments of the retransmission method of NAS message in the handoff procedure.

The tunnel of above-mentioned foundation is the unidirectional tunnel from S-eNB to T-eNB, if the handoff procedure failure, T-eNB can also return to S-eNB again with NAS message, also need set up a tunnel from T-eNB to S-eNB in this case.

Figure 16 is the schematic flow sheet of first kind of preferred embodiments of flow process shown in Figure 15, and this flow process comprises:

Step 1601:S-eNB sends handoff request message to T-eNB.

If consider the situation of handoff failure in this flow process, T-eNB can return to S-eNB with NAS message, and at this moment the handoff request message in the above-mentioned steps 1601 can be carried the IP address and the Tunnel End Point Identifier that is used for carrying out the NAS forwards of the user plane of S-eNB.

Step 1602:T-eNB sends handoff request acknowledgment message to S-eNB, carries the IP address and the Tunnel End Point Identifier that is used for carrying out the NAS forwards of the user plane of carrying T-eNB in the message in this message.

Through step 1601～step 1602, NAS transmits the tunnel and sets up, and this tunnel can be unidirectional or bidirectional tunnel.

Step 1603:UE receives the switching command message that S-eNB sends, and this information order UE accomplishes handoff procedure.

Step 1604:EPC sends descending direct-sending message to S-eNB, carries the NAS message that will issue UE in this descending direct-sending message.

Step 1605:S-eNB sends to T-eNB with the tunnel of NAS message through the forwarding NAS message of step 1601 and step 1602 foundation.This NAS message can be carried in the RRC message and forward, and like the descending direct-sending message of RRC, can also directly transmit.

Step 1606:UE sends switch acknowledgment message to T-eNB.

Step 1607:T-eNB sends handover success message to EPC, and notice EPC UE has accomplished switching.

Step 1608:EPC sends to switch to T-eNB and accomplishes response message, confirms to switch and accomplishes.

Step 1609:T-eNB utilizes the descending direct-sending message of RRC message, and NAS message is sent to UE.

Above-mentioned steps 1609 also can be in step 1606, or carries out at once after the step 1607.

In above-mentioned flow process, if handoff failure, T-eNB can return to S-eNB with NAS message through the bidirectional tunnel that step 1601～step 1602 is set up, and sends NAS message by S-eNB to UE again.

Figure 17 is the schematic flow sheet of second kind of preferred embodiments of flow process shown in Figure 15, and this flow process comprises:

Step 1701:S-eNB sends handoff request message to T-eNB.

If consider the situation of handoff failure in this flow process, T-eNB can return to S-eNB with NAS message, and at this moment the handoff request message in the above-mentioned steps 1701 can be carried the IP address and the Tunnel End Point Identifier that is used for carrying out the NAS forwards of the user plane of S-eNB.

Step 1702:T-eNB sends handoff request acknowledgment message to S-eNB, carries the IP address and the Tunnel End Point Identifier that is used for carrying out user data transmission of the user plane of carrying T-eNB in the message in this message.

Through step 1701～step 1702, the user data transmission tunnel is set up, and this tunnel can be unidirectional or bidirectional tunnel.

Step 1703～step 1704 is identical with step 1603～step 1604.

Step 1705:S-eNB sends to T-eNB with the tunnel of NAS message through the user data transmission of step 1701 and step 1702 foundation.This NAS message can be carried in the RRC message and forward, and like the descending direct-sending message of RRC, can also directly transmit.Step 1706～step 1709 is identical with step 1606～step 1609.

Above-mentioned steps 1709 also can be in step 1706, or carries out at once after the step 1707.

Because in flow process shown in Figure 17; S-eNB transmits NAS message through the tunnel of user data transmission to T-eNB; Before forwarding, need to give this NAS message to add mark, so that T-eNB can discern the message that transmission comes from same user data transmission tunnel; Which is a user data, and which is a NAS message.This mark can adopt multiple mode to add, and for example, on the packet header of GTP-U agreement, increases a tag field.

The user data transmission tunnel of above-mentioned forwarding NAS message; Can be in many user data transmission tunnels of setting up between S-eNB and the T-eNB; Concrete which bar tunnel of selecting also carries out the forwarding of NAS message in transmitting user data, the multiple choices mode is arranged, for example can be according to selective sequential; Or according to the load sharing selection, or select at random etc.

In above-mentioned flow process, if handoff failure, T-eNB can return to S-eNB with NAS message through the bidirectional tunnel that step 1801～step 1802 is set up, and sends NAS message by S-eNB to UE again.

In the flow process shown in Figure 15; When handoff failure, by S-eNB NAS message is sent to UE, specifically can comprise two kinds of execution modes; Figure 18 sends to first kind of preferred embodiments schematic flow sheet of UE by S-eNB with NAS message during for flow process handoff failure shown in Figure 15, and this flow process comprises:

The NAS message that mails to UE that step 1801:S-eNB backup EPC sends.

Step 1802: if handoff failure, S-eNB sends the NAS message of said backup to UE.

In this preferred embodiments, S-eNB when the handoff failure, sends with the NAS message of backup NAS backup to UE, correctly send NAS message to UE when realizing handoff failure.

Above-mentioned S-eNB before UE sends, may further include the NAS message that is backed up: S-eNB initiates the handover cancelling flow process to T-eNB.

Figure 19 sends to second kind of preferred embodiments schematic flow sheet of UE by S-eNB with NAS message during for flow process handoff failure shown in Figure 15, and this flow process comprises:

Step 1901:S-eNB receives the NAS message that mails to UE that EPC sends, and said NAS message is sent to T-eNB.

Step 1902: if handoff failure, S-eNB receives the said NAS message that T-eNB sends.

Step 1903:S-eNB sends said NAS message to UE.

In this preferred embodiments, when UE switched, S-eNB gave T-eNB with the NAS forwards that receives; If handoff failure; T-eNB is transmitted to S-eNB again with NAS message, by S-eNB NAS message is sent to UE, when handoff failure; Through between S-eNB and T-eNB, transmitting NAS message, realized correctly sending NAS message to UE.

The said NAS message that above-mentioned S-eNB receives the T-eNB transmission further comprises before: S-eNB initiates the handover cancelling flow process to T-eNB.

Secondly, introduce in the embodiment of the invention evolvement network processing unit of NAS message in the handoff procedure, comprise two kinds of devices, the mobile management entity MME among evolution base station and the EPC, wherein the MME among the EPC comprises two kinds of situation again.

Figure 20 is the structural representation of the MME among first kind of EPC of the embodiment of the invention, comprises among this MME: information receiving and transmitting module 2001 and Executive Module 2002.

Information receiving and transmitting module 2001 is used to receive the message that UE that S-eNB sends is switching, and is transferred to Executive Module 2002; When handoff failure, the UE that receives the S-eNB transmission returns the information of S-eNB coverage, is transferred to Executive Module 2002.

Executive Module 2002 is used to receive the message that the UE of information receiving and transmitting module 2001 transmission is switching, the NAS message that buffer memory sends to UE; The UE that receives 2001 transmission of information receiving and transmitting module returns the information of S-eNB coverage,, when UE sends NAS message, the NAS message of issuing UE is sent to S-eNB at needs.

MME among first kind of EPC that the embodiment of the invention provides through the message that the UE that receives from S-eNB is switching, know that UE switches, thereby buffer memory sends NAS message to UE; During handoff failure,, when UE sends NAS message, continue to send NAS message to UE, realized when handoff failure, correctly sending NAS message to UE through S-eNB at needs through receiving the message that UE that S-eNB sends returns the S-eNB coverage.

Above-mentioned information receiving and transmitting module 2001 can also be used for when handover success; Receive the UE handoff completion message that T-eNB sends; Be transferred to Executive Module 2002, above-mentioned Executive Module 2002 can also be used to receive the UE handoff completion message that the T-eNB of information receiving and transmitting module transmission sends when handover success;, when UE sends NAS message, NAS message is sent to UE at needs.

Therefore, the MME among the EPC that the embodiment of the invention provides not only can be behind handoff failure; Need, UE correctly send NAS message to UE when sending NAS message through S-eNB, and can also be behind handover success; When needing to send NAS message, correctly send NAS message to UE through T-eNB.

Figure 21 is the structural representation of the MME among second kind of EPC of the embodiment of the invention, comprises among this MME: control module 2101, retransmission timer 2103 and Executive Module 2104.

Control module 2101 is used to receive the message that UE that S-eNB sends is switching, and starts retransmission timer 2103; Receive the handoff completion message that T-eNB sends, stop retransmission timer 2103.

Executive Module 2104 is used for the timing results according to retransmission timer 2103, after retransmission timer 2103 is overtime; When UE sends NAS message, send NAS message to S-eNB, at needs after retransmission timer 2103 stops; When UE sends NAS message, send NAS message at needs to T-eNB.

MME among second kind of EPC that the embodiment of the invention provides through the message that the UE that receives from S-eNB is switching, knows that UE switches, and starts retransmission timer; After retransmission timer is overtime, when UE sends NAS message, continue to send NAS message to UE through S-eNB at needs; When handover success; Stop retransmission timer, and send NAS message to UE, realized when handoff failure or success, correctly sending NAS message to UE through T-eNB.

Above-mentioned retransmission timer 2103 can be S1 Application of Interface part protocol retransmission timer.

Carry temporal information in the message that the UE that above-mentioned control module 2101 receives is switching; At this moment may further include calculation control module 2102 among this MME; Be used to resolve said temporal information; Length according to temporal information calculating retransmission timer 2103 is transferred to control module 2101 with result of calculation.

When in the message that UE is switching, carrying temporal information, MME can confirm the length of retransmission timer accurately according to this temporal information.

At last, introduce three kinds of evolution base stations that the embodiment of the invention provides in detail, Figure 22 is the structural representation of first kind of evolution base station of the embodiment of the invention, and this base station comprises: detection module 2201, hand-off process module 2202 and NAS message transmitting module 2203.

Detection module 2201 is used for detecting the abnormality that UE switches, and testing result is sent to hand-off process module 2202;

Hand-off process module 2202 is used for sending the message that UE is switching to EPC; According to the testing result that detection module 2201 sends, when the UE handoff failure, send the message of the current affiliated coverage of UE to EPC;

NAS message transmitting module 2203 is used to receive the NAS message that EPC sends, and is transmitted to UE.

In practical application, according to the concrete condition of using, evolution base station maybe be as S-eNB, also maybe be, so first kind of evolution base station providing of the invention described above embodiment as T-eNB, comprised the function when evolution base station is as S-eNB and T-eNB.

First kind of evolution base station that the embodiment of the invention provides, when handoff failure to EPC send UE current under the message of coverage, make EPC realize correct sending NAS message to UE according to this message.

The structural representation of second kind of evolution base station that Figure 23 provides for the embodiment of the invention comprises in this evolution base station: detection module 2301, temporal information module 2302, hand-off process module 2303 and NAS message transmitting module 2304.

Detection module 2301 is used for detecting the abnormality that UE switches, and testing result is sent to hand-off process module 2303.

Temporal information module 2302 is used for the result according to hand-off process module 2303, UE is switched time information corresponding send to hand-off process module 2303.

Hand-off process module 2303 is used for sending the message that UE is switching to EPC, and the temporal information that temporal information module 2302 is provided is carried in the message that said UE switching; According to the testing result that detection module 2301 sends, when the UE handoff failure, send the message of the current affiliated coverage of UE to EPC.

Said NAS message transmitting module 2304 is used to receive the NAS message that EPC sends, and is transmitted to UE.

Second kind of evolution base station that the embodiment of the invention provides; Through carrying temporal information in the message of switching at the UE that sends to EPC, make EPC confirm the length of retransmission timer according to this temporal information; Utilize retransmission timer overtime, the correct NAS message of sending when the UE handoff failure.

The structural representation of the third evolution base station that Figure 24 provides for the embodiment of the invention comprises in this evolution base station: information receiving and transmitting module 2401 and message processing module 2402.

Information receiving and transmitting module 2401; Be used to receive the NAS message that mails to UE that EPC sends; The X2 interface control protocol message of carrying NAS message in the said NAS message processing module is sent to other base stations, and the said NAS message that maybe will receive is sent to other base stations through the tunnel; Receive the NAS message that other evolution base stations use X2 interface control protocol message or send through the tunnel; The NAS message that receives is sent to UE.

NAS message processing module 2402 is used for the NAS message with said information receiving and transmitting module 2401 receptions, is carried in the X2 interface control protocol message.

The third evolution base station that the embodiment of the invention provides; Use X2 interface control protocol message bearing NAS message; And pass through the X2 interface control messages and between evolution base station, transmit NAS message; Or the tunnel forwarding NAS message through setting up between the evolution base station, for NAS message provides concrete implementation in the X2 interface forwarding.

In the third evolution base station that the embodiment of the invention provides; Can also comprise that the tunnel sets up module 2403; Be used to receive the user plane IP address and the Tunnel End Point Identifier of corresponding other evolution base stations; User plane IP address and Tunnel End Point Identifier that self is corresponding send to said other evolution base stations, set up NAS forwarding tunnel or user data transmission tunnel between self and other evolution base stations.

If the user data transmission tunnel of above-mentioned foundation has more than one; Can also comprise selection module 2404 in tunnel in the third evolution base station that then embodiment of the invention provides, be used for selecting one and be used to transmit said NAS message from the user data transmission tunnel of said foundation.And can also comprise in this evolution base station that mark adds module 2405, when other evolution base stations send NAS message, be that the NAS message of being sent is added mark in the said user data transmission tunnel that passes through to set up.The purpose of above-mentioned interpolation mark is, when NAS message and user data were shared said user data transmission tunnel and sent, making the evolution base station of reception that which can correctly be discerned was NAS message.

In the third evolution base station that the embodiment of the invention provides, can also comprise backup module 2406, be used to back up the NAS message that mails to UE that said information receiving and transmitting module 2401 receives.Through increasing this backup module 2405, evolution base station can send the NAS message of backup when handoff failure to UE.

Three kinds of base stations that the invention described above embodiment provides have all comprised the function of this evolution base station as S-eNB and T-eNB respectively.

The processing method of NAS message and device in the handoff procedure in the evolvement network that the embodiment of the invention provides inform that the EPC current UE switches, and make the EPC buffer memory send NAS message to UE; When handoff failure, send the message that UE returns the S-eNB coverage by S-eNB to EPC, make EPC correctly send NAS message to UE; Retransmission timer perhaps is set; Inform that the EPC current UE switches, make EPC start retransmission timer, when handoff failure; EPC can correctly send NAS message to UE through S-eNB after retransmission timer is overtime; When handover success, EPC can stop retransmission timer, and sends NAS message through T-eNB to UE; Perhaps through X2 interface control protocol or tunnel with the NAS forwards to T-eNB, for the forwarding of NAS message through X2 interface provides concrete implementation.

In sum, more than being merely preferred embodiment of the present invention, is not to be used to limit protection scope of the present invention.All within spirit of the present invention and principle, any modification of being done, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims

1. the processing method of non-access layer information in the handoff procedure in the evolvement network is characterized in that this method comprises:

Source evolution base station S-eNB receives the direct-sending message that the mobile management entity MME among the evolution block core EPC is sent, and carries the non access stratum NAS message that MME among the said EPC issues user equipment (UE) in the said direct-sending message;

The MME of said S-eNB in said EPC sends the direct transfer failed message or the response message that direct transfers; That carries in said the direct transfer failed message or the response message that direct transfers that cause value and the MME from said EPC receive sends successful NAS message to said UE, and the cause value that carries in said the direct transfer failed message or the response message that direct transfers comprises that UE switches.

2. an evolution base station eNB is characterized in that, comprising:

Transmit-Receive Unit is used for receiving the direct-sending message that the mobile management entity MME of evolution block core EPC is sent, and carries the non access stratum NAS message that MME among the said EPC issues user equipment (UE) in the said direct-sending message; Also be used for sending the direct transfer failed message or the response message that direct transfers to the MME of said EPC; That carries in said the direct transfer failed message or the response message that direct transfers that cause value and the MME from said EPC receive sends successful NAS message to said UE, and the cause value that carries in said the direct transfer failed message or the response message that direct transfers comprises that UE switches.

3. the mobile management entity in the mobile management core is characterized in that, comprising:

Transmit-Receive Unit is used for sending direct-sending message to evolution base station eNB, carries the non access stratum NAS message that MME among the said EPC issues user equipment (UE) in the said direct-sending message; Also be used to receive the direct transfer failed message or the response message that direct transfers that said eNB sends; That carries in said the direct transfer failed message or the response message that direct transfers that cause value and the MME from said EPC receive sends successful NAS message to said UE, and the cause value that carries in said the direct transfer failed message or the response message that direct transfers comprises that UE switches.

4. an evolvement network is characterized in that, comprises eNB as claimed in claim 2 and mobile management entity as claimed in claim 3.