CN103220735A

CN103220735A - User plane building method after RN moves

Info

Publication number: CN103220735A
Application number: CN201210016689.8A
Authority: CN
Inventors: 王弘; 许丽香
Original assignee: Beijing Samsung Telecommunications Technology Research Co Ltd; Samsung Electronics Co Ltd
Current assignee: Beijing Samsung Telecommunications Technology Research Co Ltd; Samsung Electronics Co Ltd
Priority date: 2012-01-18
Filing date: 2012-01-18
Publication date: 2013-07-24
Also published as: WO2013109063A1

Abstract

The invention discloses a user plane building method after an RN moves. Tunnel building between a target DeNB of the moving RN and a gateway serving the RN is carried out in the switching process of S1 or X2 or after switching is finished. When an S1 interface is built after the switching is finished, tunnel building between the moving RN and the target DeNB is carried out. The method can achieve building of a user plane when the RN moves to the new DeNB, and enables the switching process to be open to UE so as to guarantee continuity of data transmission.

Description

Method for establishing user plane after RN moves

Technical Field

The invention relates to the field of mobile communication systems, in particular to a method for establishing a user plane after RN moves.

Background

Fig. 1 is a schematic diagram of an LTE structure supporting a Relay (RN) in the prior art, as shown in fig. 1, in a radio access network of an LTE system, a radio resource management entity includes a macro base station (eNB)101 and a relay 102, and the RN accesses a core network through another macro base station (DeNB) 103. Wherein, the eNBs 101 are connected through an X2 interface, and each eNB 101 is connected with a Mobile Management Entity (MME) and a service network management (S-GW)104 in a core network through an S1 interface; RN 102 accesses DeNB 103 through a Un interface. DeNB 103 provides X2 proxy (proxy) functionality between RN 102 and other enbs. DeNB 103 provides S1 proxy (proxy) functionality between RN 102 and MME/S-GW 104. The proxy functions of S1 and X2 include the transport of UE-specific X2 and S1 signaling between RN 102 and eNB 101, RN 102 and MME 104, and between RN 102 and S-GW 104.

Fig. 1 is a block diagram of a current fixed relay. The S1, X2 and Un interfaces terminate in fixed relays. DeNB provides proxy functionality between RN and DeNB, RN and other nodes, such as MME, other enbs, S1 and X2. The Proxy functions include: UE-specific S1 and X2 messages are transmitted over S1 and X2 interfaces, GTP packets between RNs and denbs, RNs and other network nodes are transmitted. Due to proxy functionality, the DeNB appears to the RN as a combination of the functionality of the MME, other enbs and S-GW.

The process of RN connection to DeNB is divided into two phases.

Stage one: pre-configuration phase of RN.

The RN is taken as a UE and attached to the E-UTRAN/EPC, the attaching process is the same as that of the ordinary UE, and the MME takes the RN as the ordinary UE to select the S-GW and the P-GW for the RN. And the MME serving the RN is called RN-MME, and obtains the most initial configuration parameters from the operation maintenance of the RN, wherein the configuration parameters at least comprise a list of DeNB cells to which the RN can be connected. When the process is finished, the RN leaves the network through the detach process, and enters the stage two.

And a second stage: and (5) working phase of RN.

And the RN selects one DeNB from a cell list of the pre-configured DeNB to start entering a normal working state. And when the DeNB initiates S1/X2 bearer establishment, the RN initiates S1/X2 bearer establishment between the RN and the DeNB. The DeNB may initiate an RRC reconfiguration procedure of the RN to update parameters of the RN.

After S1 establishment, if the configuration parameters change, the DeNB initiates an eNB configuration update procedure of S1. After the X2 interface is established, the DeNB initiates an X2 eNB configuration update procedure to update the configuration information of the cell. At this stage, the cell identity ECGI of the RN is configured by the RN OAM.

In phase two, the DeNB provides the function of S-GW/P-GW of RN, including: and establishing a session and management bearer for the RN, and providing the function of S11. The functions of the P-GW above the DeNB also include the allocation of an IP address to the RN, and the communication between the RN and the OAM. This address may be different from the IP address of the DeNB.

The RN and DeNB are to map signaling and data onto the EPS bearer established for the RN. The mapping mechanism is based on the currently defined Qos mechanism between the UE and the P-GW.

Fig. 2 shows the attachment procedure of RN. This procedure is essentially the same as the normal UE attach procedure, except that:

in the process that the DeNB establishes an S1 interface with the MME, the DeNB knows which MME support the RN function through an S1 establishment response message;

2. in step 1, the RN and the DeNB establish the RRC connection process, and the RN sends an RN instruction to the DeNB;

3. in step 4b, in an initial UE message in the process of establishing the context of the UE with the S1 interface, the DeNB needs to send an RN instruction and the IP address of the S-GW/P-GW to the MME;

4. in the attaching process, the EPC checks whether the RN is authenticated, only when the RN is the authenticated RN, the EPC accepts the attaching process and establishes a context with the DeNB; otherwise, the EPC rejects the attach procedure.

The UE is attached to the network through the RN, the MME serving the UE is called UE-MME, and the RN-MME and the UE-MME can be the same MME or different MMEs. The GW of RN, including SGW and PGW, is currently in the same entity as DeNB. The SGW and PGW implement different functions, which are collectively referred to as the GW of the RN for simplicity of description, and actually contain two different functions.

Relays are currently defined for fixed location and do not support relay mobility between different cells. The current mechanism is not suitable for the scenario of trains moving at high speed. High-speed trains are rapidly developed, the moving speed is high, for example, 250-. The service quality provided by the existing relay can not meet the requirements of operators, and the mobile relay aims to solve the problems of the existing relay, improve the quality of the service provided by a high-speed train and better meet the requirements of users.

The mobile relay and the fixed relay are different in that the DeNB of the mobile relay changes during the moving process, and during the handover, the bearer, the context, and the user of the mobile relay all need to be handed over to the destination DeNB, and the data continuity needs to be ensured. The current protocol does not discuss how this aspect is supported. A user plane for transmitting UE information needs to be established between the destination DeNB and the RN-GW, the establishment of an S1 interface between the mobile RN and the destination DeNB is implemented, the user plane between the mobile RN and the destination DeNB is established, and the switching process of the RN is guaranteed to be transparent to the UE as much as possible.

The invention relates to how RN switches from DeNB to DeNB when RN moves, how UE switches to DeNB along with RN, how to establish new connection with DeNB, how to ensure continuous data reception, and reduce message interaction in switching process, wherein switching process is as transparent as possible to UE and core network.

Disclosure of Invention

The invention provides a method for supporting group switching and continuous data receiving, which can reduce unnecessary signaling flow and network congestion in a high-speed mobile environment.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method for establishing a tunnel between a DeNB of a mobile relay and a gateway of the mobile relay, when the mobile Relay (RN) is switched to a new DeNB through an S1 interface, the method comprises the following steps:

A. a source DeNB of the mobile RN sends a switching required message to a mobile management entity (RN-MME) serving the RN, wherein the message contains the identification of each UE served by the mobile RN and uplink tunnel information distributed to the UE by a gateway (RN-GW) of the mobile RN;

B. the RN-MME sends a switching request message to a destination DeNB of the mobile RN, wherein the message contains the identification of each UE served by the mobile RN and uplink tunnel information distributed by the RN-GW for the corresponding UE;

C. the target DeNB sends a switching response message to the RN-MME, wherein the message comprises: the destination DeNB distributes an S1 interface new identifier and downlink tunnel information for each UE served by the mobile RN;

D. and the RN-MME or the destination DeNB sends an S1 interface new identifier and downlink tunnel information distributed by the destination DeNB for each UE served by the mobile RN to the RN-GW.

Preferably, the step D is: the RN-MME sends a request for changing the bearing establishment to the RN-GW, wherein the message contains an S1 interface new identifier and downlink tunnel information which are distributed by the target DeNB for each UE served by the mobile RN;

or,

and the destination DeNB sends a path updating message to the RN-GW, wherein the path updating message comprises an S1 interface new identifier and downlink tunnel information which are distributed by the destination DeNB for each UE served by the RN.

Preferably, after said step D, the method further comprises the step E: the RN-MME sends a UE context release command message to the source DeNB, wherein the message contains the identification of all UE served by the mobile RN, and the source DeNB releases the context information of the mobile RN and the context information of all UE served by the mobile RN after receiving the UE context release command message.

Preferably, after the step E, the method further comprises: and establishing an S1 interface between the mobile RN and the destination DeNB, and keeping the context information of all the UE served by the mobile RN unchanged.

Preferably, after the switching of S1 is completed, the method further includes:

for each UE served by the mobile RN, the destination DeNB sends the identifier of the corresponding UE and the S1 interface new identifier allocated by the destination DeNB for the corresponding UE to a (UE-MME) serving the corresponding UE, and the UE-MME is used for updating the UE information on the UE-MME; the UE-MME allocates an S1 interface new identifier for the corresponding UE and informs the target DeNB;

and the UE-MME or the destination DeNB sends S1 interface new identification which is allocated by the UE-MME for each UE served by the mobile RN to the RN-GW.

Preferably, the handover required message in step a further includes information that the mobile RN is used as a UE, where the information includes an S1 interface old identifier of the mobile RN between a source DeNB and an RN-MME;

the handover request message in step B further includes an S1 interface new identifier allocated by the RN-MME to the mobile RN and uplink tunnel information allocated by the RN-GW to the mobile RN;

the handover response message in step C further includes an S1 interface new identifier allocated by the RN-MME for the mobile RN, an S1 interface new identifier allocated by the destination DeNB for the mobile RN, and downlink tunnel information;

after the step C and before the step D, the method further comprises the following steps: the RN-MME sends switching command information to the source DeNB, wherein the switching command information comprises an S1 interface new identifier distributed by the mobile RN and an S1 interface new identifier distributed by a target DeNB for the mobile RN;

the step D further comprises the following steps: and the RN-MME sends downlink tunnel information distributed by the destination DeNB for the mobile RN to the RN-GW.

A tunnel establishment method between a DeNB and a mobile relay gateway of a mobile relay, when the mobile Relay (RN) is switched to a new DeNB through an X2 interface, the method comprises the following steps:

A. a source DeNB of the mobile RN sends a switching request message to a target DeNB, wherein the message contains the identification of each UE served by the mobile RN and uplink tunnel information distributed to the UE by a gateway (RN-GW) of the mobile RN;

B. the target DeNB sends a switching response message to the source DeNB, wherein the message contains a new identifier and downlink tunnel information which are distributed by the target DeNB for each UE served by the mobile RN;

C. and the destination DeNB forwards the SI interface new identification and the downlink tunnel information which are distributed by the destination DeNB for each UE served by the mobile RN to the RN-GW through a mobile management entity (RN-MME) serving the RN.

Preferably, after said step C, the method further comprises the step D of: the RN-MME sends a UE context release command message to the source DeNB, wherein the message contains the identification of all UE served by the mobile RN, and the source DeNB releases the context information of the mobile RN and the context information of all UE served by the mobile RN after receiving the UE context release command message.

Preferably, after the step D, the method further comprises: and establishing an S1 interface between the mobile RN and the destination DeNB, and keeping the context information of all the UE served by the mobile RN unchanged.

Preferably, after the X2 handover is completed, the method further comprises:

for each UE served by the mobile RN, the destination DeNB sends the identifier of the corresponding UE and the S1 interface new identifier allocated by the destination DeNB for the corresponding UE to a (UE-MME) serving the UE, and the identifier and the new identifier are used for updating the information of the corresponding UE stored in the UE-MME;

the UE-MME sends an identifier of corresponding UE, an S1 interface new identifier distributed by a target DeNB for the corresponding UE, and an S1 interface new identifier distributed by the UE-MME for the corresponding UE to the RN-GW, and is used for updating the information of the corresponding UE stored in the RN-GW;

and the UE-MME sends the S1 interface new identification allocated by the UE-MME for the corresponding UE to the destination DeNB.

Preferably, the handover request message in step a further includes information that the mobile RN is used as UE, where the information includes an old identifier of the mobile RN on a source DeNB and uplink tunnel information allocated to the mobile RN by the RN-GW;

the switching response message of the step B also comprises an old identifier of the mobile RN on a source DeNB, a new identifier of the mobile RN on a target DeNB and downlink tunnel information distributed by the target DeNB for the mobile RN;

and C, when the target DeNB forwards the UE information to the RN-GW through the RN-MME in the step C, forwarding downlink tunnel information distributed for the mobile RN by the target DeNB to the RN-GW through the RN-MME, and sending a new identifier of the mobile RN on the target DeNB to the RN-MME.

A method for establishing a tunnel between a DeNB of a mobile relay and the mobile relay, after the mobile Relay (RN) is switched to a new DeNB, the method comprises the following steps:

A. the mobile RN sends an S1 establishment request message to the DeNB, wherein the message contains an S1 interface new identifier distributed by the DeNB for each UE during switching and current context information of each UE;

B. and the DeNB sends an S1 establishment response message to the mobile RN, wherein the message comprises the S1 interface new identification and uplink tunnel information which are distributed by the DeNB for each UE.

Preferably, the S1 setup request message in step a further includes a base station identifier of the mobile RN and supported TAI text information;

the S1 setup response message in step B includes the new identifier of the S1 interface and the uplink tunnel information allocated by the destination DeNB to each UE.

A method for establishing a tunnel between a DeNB and a mobile relay gateway of a mobile relay, after the mobile Relay (RN) is switched to a new DeNB, the method comprises the following steps:

A. the DeNB sends an S1 interface new identifier and downlink tunnel information distributed by the DeNB for the UE when switching to a gateway (RN-GW) of the mobile RN through an MME (UE-MME) of the UE; the UE serving each UE of the mobile RN;

B. and the RN-GW sends uplink tunnel information distributed by the RN-GW for the UE to the DeNB through the UE-MME.

Preferably, the step a is: the DeNB sends a path switching request message to the UE-MME, the UE-MME sends a bearer change request message to the RN-GW, and the path switching request message and the bearer change request message comprise an S1 interface new identifier and downlink tunnel information distributed by the DeNB for corresponding UE;

the step B is as follows: and the RN-GW sends a bearer change response message to the UE-MME, the UE-MME sends a path switching request confirmation message to the DeNB, and the bearer change response message and the path switching request confirmation message contain uplink tunnel information distributed by the RN-GW for the corresponding UE.

Preferably, the bearer change request message in step a further includes an S1 interface new identifier allocated by the UE-MME to the corresponding UE;

and B, the path switching request acknowledgement message in step B further includes an S1 interface new identifier allocated by the UE-MME to the corresponding UE.

Preferably, when the mobile RN is handed over to the DeNB through S1, before the S1 handover is completed, the method further comprises:

the method comprises the steps that a handover required message sent by a handover source DeNB to a mobile management entity (RN-MME) serving the mobile RN contains information of the mobile RN as UE, wherein the handover required message contains an S1 interface old identifier of the mobile RN between the source DeNB and the RN-MME;

the switching request message sent by the RN-MME to the DeNB also comprises an S1 interface new identifier distributed by the RN-MME for the mobile RN and uplink tunnel information distributed by the RN-GW for the mobile RN;

the handover response message sent by the DeNB to the RN-MME also includes an S1 interface new identifier allocated by the RN-MME for the mobile RN, an S1 interface new identifier allocated by the DeNB for the mobile RN, and downlink tunnel information;

the switching command message sent by the RN-MME to the source DeNB comprises an S1 interface new identifier allocated by the mobile RN and an S1 interface new identifier allocated by the DeNB for the mobile RN;

and the change bearer request message sent by the RN-MME to the RN-GW contains downlink tunnel information distributed by the DeNB for the mobile RN.

Preferably, when the mobile RN is handed over to the DeNB through X2, before the X2 handover is completed, the method further comprises:

the method comprises the steps that a switching request message sent to a DeNB by a switching source DeNB contains information of a mobile RN as UE, wherein the information contains an old identifier of the mobile RN on the source DeNB and uplink tunnel information distributed by an RN-GW for the mobile RN;

the switching response message sent by the DeNB to the source DeNB includes the old identifier of the mobile RN on the source DeNB, the new identifier of the mobile RN on the DeNB and the uplink tunnel information which is accepted by the DeNB and allocated for the mobile RN;

and in a path switching message sent by the DeNB to the RN-MME and a bearer change request message sent by the RN-MME to the RN-GW, the downlink tunnel information allocated by the DeNB to the mobile RN is included, and the path switching message includes a new identifier of the mobile RN on the DeNB.

According to the technical scheme, in the invention, in the switching process of S1 or X2 or after the switching is finished, the tunnel between the target DeNB of the mobile RN and the gateway of the service RN is established; when the interface S1 is established after the handover is completed, a tunnel is established between the mobile RN and the destination DeNB. By applying the user plane establishing method of the invention, the establishment of the user plane can be realized when the RN moves to a new DeNB, the switching process is transparent to the UE, and the continuity of data transmission is ensured.

Drawings

Fig. 1 is a schematic diagram of an LTE structure supporting a Relay (RN) in the prior art;

FIG. 2 is a simplified procedure for attachment of conventional RN;

FIG. 3 is a first schematic diagram of the present invention;

FIG. 4 is a second schematic diagram of the present invention;

FIG. 5 is a third schematic diagram of the present invention;

FIG. 6 is a fourth schematic diagram of the operation of the present invention;

fig. 7 is a flowchart of a first embodiment of the RN switching to the destination DeNB through S1;

fig. 8 is a flowchart of the operation of the second embodiment in which the RN switches to the destination DeNB through S1;

fig. 9 is a flowchart of the operation of the third embodiment in which the RN switches to the destination DeNB through X2;

fig. 10 is a flowchart of the operation of the fourth embodiment in which the RN switches to the destination DeNB through X2.

Detailed Description

For the purpose of making the objects, technical means and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings.

The invention provides a user plane establishment method after a mobile RN is switched to a target DeNB, which comprises a user plane of the RN and a user plane of UE served by the RN, wherein the user plane establishment can be realized in an S1 switching process or an X2 switching process, and the user plane establishment can also be realized after the mobile RN completes the switching.

Meanwhile, the invention also provides a tunnel establishment method for transmitting UE data between the DeNB of the mobile RN and the mobile RN, and the process can be completed when the S1 interface is established. Next, the method provided by the present invention will be described in detail.

The user plane comprises three tunnels from UE-GW to RN-GW, between RN-GW and DeNB and between DeNB and RN. The tunnel between the UE-GW and the RN-GW is not changed in the switching process, so that the switching process of the RN is transparent to the UE. Fig. 3 depicts a flow of a method for implementing tunnel establishment between the DeNB and the RN-GW during S1 handover. The method flow describes that when the RN is handed over to the destination DeNB, an S1 handover process is initiated, and a handover required message carries identification information, bearer information, and the like of an S1 interface of the UE to establish a tunnel with an SGW/PGW (hereinafter referred to as RN-GW) of the RN for transmitting data of the UE. As shown in fig. 3, the process includes:

step 301: a source DeNB sends a switching required message to an MME, wherein the message comprises RN information and information of each UE served by the RN, and specifically, the UE information comprises UE identification and uplink tunnel information distributed by an RNGW;

step 302: the MME sends a switching request message to a target DeNB, wherein the message comprises RN information and RN-served UE information, and specifically, the UE information comprises UE identification and RNGW-allocated uplink tunnel information;

step 303: the target DeNB sends a switching response message to the MME, wherein the message comprises RN information and UE information, and specifically, the UE information comprises an identifier of the UE on an S1 interface and downlink tunnel information distributed by the T-DeNB;

step 304: and the MME or the target DeNB sends the RN information and the UE information to the RN-GW, wherein the UE information specifically comprises an S1 interface new identifier and downlink tunnel information which are distributed to the UE by the target DeNB.

It should be noted that a tunnel between the DeNB and the RN-GW may also be established after the S1 handover, and at this time, only the UE identification information and the UE context information are transferred to the T-DeNB during the S1 handover.

Fig. 4 is a flow of a method for establishing a tunnel between a DeNB and an RN-GW in an X2 handover process according to the present invention. The method flow describes that when the RN is switched to the target DeNB, the switching process of the X2 is initiated, and the switching request message carries the identification information, the bearing information and the like of the S1 interface of the UE to establish a tunnel with the SGW/PGW of the RN for transmitting the data of the UE. As shown in fig. 4, the process includes:

step 401: a source DeNB sends a switching request message to a target DeNB, wherein the message comprises RN information and RN-served UE information, specifically, the UE information comprises UE identification and RN GW-allocated uplink tunnel information;

step 402: the target DeNB sends a switching response message to the source DeNB, wherein the message comprises RN information and RN-served UE information, and specifically, the UE information comprises a new identifier and downlink tunnel information which are allocated by the target DeNB for each UE served by the mobile RN;

step 403: the target DeNB sends a message to the MME, the MME sends a message to the RN-GW, and the message comprises the information of the UE, specifically, the information of the UE comprises a new identifier of the UE at an S1 interface and downlink tunnel information distributed by the target DeNB;

step 404: and the RN-GW sends a message to the MME, and the MME sends a message to a target DeNB, wherein the message comprises the information of the UE, specifically, the information of the UE comprises a new identifier of the UE at an S1 interface and uplink tunnel information distributed by the target RN-GW.

It should be noted that a tunnel between the DeNB and the RN-GW may also be established after the handover, at this time, in the process of the X2 handover, only the identification information of the UE and the context information of the UE may be transferred to the T-DeNB, or the context information of the UE may not be transferred in the handover process, or the context information of the UE may be transferred to the T-DeNB in the flow shown in fig. 6. If the context of the UE is transferred to the T-DeNB during the RN handover procedure, the RN is not required to transfer the context information of the UE to the T-DeNB in the procedure shown in fig. 6.

Fig. 5 is a flow of a method for establishing a tunnel between a DeNB and an RN-GW after S1 handover or X2 handover is completed according to the present invention. The procedure describes that when the RN switches to the target DeNB, a switching process of S1 or X2 is initiated, and after the switching is completed, a tunnel between the T-DeNB and the SGW/PGW of the RN is established for transmitting the data of the UE. As shown in fig. 5, the process includes:

step 501: the DeNB sends a message to the UE-MME, the UE-MME sends a message to the RN-GW, and the message contains an S1 interface new identifier distributed by the DeNB for the UE and downlink tunnel information distributed by the DeNB for the UE; wherein, the UE refers to the UE served by the mobile RN;

step 502: and the RN-GW sends a message to the UE-MME, and the UE-MME sends a message to the DeNB, wherein the message contains the uplink tunnel information distributed by the RN-GW for the UE. A tunnel between the RN-GW and the DeNB is established.

Through the above processing in fig. 3, 4 and 5, the destination DeNB allocates a new S1 interface identifier and downlink tunnel information to the UE under the mobile RN and notifies the RN-GW, and meanwhile, the destination DeNB also acquires uplink tunnel information allocated to the UE before the RN-GW through the source DeNB and the RN-MME, so that a tunnel for transmitting UE data can be established between the destination DeNB and the RN-GW.

Fig. 6 is a flow chart of the method for establishing the S1 interface between the DeNB and the RN after the S1 handover or the X2 handover is completed according to the present invention. The process describes that when the RN switches to the destination DeNB, a switching process of S1 or X2 is initiated, and after the switching is completed, an S1 interface between the DeNB and the RN is established, and tunnel information between the DeNB and the mobile RN is transmitted at the same time. As shown in fig. 6, the process includes:

step 601: the RN sends S1a request message for establishing to a destination DeNB, the message contains information of each UE served by the mobile RN, specifically, the UE information contains new identification of an S1 interface of the UE and current context information when the DeNB is switched;

step 602: the DeNB sends S1a response message to the RN, wherein the message contains the information of each UE served by the mobile RN; specifically, the UE information includes UE context information such as UE identity, bearer information, and the like on the S1 interface.

Through the process shown in fig. 6, the S1 interface is established, and at the same time, tunnel information between the RN and the DeNB can be transmitted, so that UE data can be transmitted between the RN and the DeNB.

Example one

An embodiment is a flowchart of the RN switching to the destination DeNB through the S1 interface. The S/P GW of the RN is not changed. In the process of RN switching, a tunnel for transmitting data between the S/PGW and the T-DeNB of the RN is established for the UE. The RN is switched to the destination DeNB, and the MME served by the RN can also be switched to the new MME. Embodiment one the serving MME of RN (RN-MME) is not changed to an example. It also involves the transfer of messages between the source MME and the destination MME if the serving MME of the RN changes. Fig. 7 omits messages between the source MME and the destination MME. The following is a detailed description of fig. 7:

step 701: the RN measures the surrounding radio environment and transmits a measurement report to a serving DeNB (S-DeNB in the drawing). Based on the measurement report, the S-DeNB decides to switch the RN to the destination DeNB (T-DeNB in the figure) with better signal quality.

Step 702: the S-DeNB sends a handover required message to a serving MME of the RN, namely the RN-MME in the figure, wherein the handover required message comprises the existing information taking the RN as the UE. The RN includes as the existing information of the UE:

identification of the old S1 interface of the RN between the S-DeNB and the RN-MME: eNB UE S1 APID, MME UE S1AP ID;

-handover type, where handover type is a handover type of a mobile relay.

-destination address of handover, here identification of destination T-DeNB of handover, whereby identification MME can find T-DeNB.

-a container for transparent transmission of the source to the destination,

the handover required message further includes information of the UE served by the RN. This information is included in order to establish a tunnel for transmitting data for the UE between the gateway (SGW and PGW) of the RN and the T-DeNB. The UE information includes UE identity and tunnel information (the UE information may include one or more or all of the following):

identification of UE on old S1 interface between S-DeNB and UE-MME: eNB UE S1 APID, MME UE S1AP ID;

an identity of the UE, e.g. a temporary identity S-TMSI of the UE.

E-RAB information of the UE, e.g. E-RAB identity, uplink TEID and transport layer address allocated by the RN-GW, Qos information.

-context information of the UE, such as ciphering capability of the UE, access stratum capability information, maximum rate of the UE at the S1 interface; RRC context, handover restriction list, location reporting information.

The UE identity is an old identity of the UE before RN handover, and may be one or any combination of the above identities, and is used to identify the corresponding UE. Generally, the old UE identity appearing in the subsequently sent message is the same as the UE identity of this step. In addition, the S1 interface identification of the UE is divided into S1 interface identification allocated by DeNB eNB UE S1AP ID and S1 interface identification allocated by MME S1AP ID, and the S1 interface identification including RN as UE is also divided into the two types, when switching is carried out, the target DeNB allocates S1 interface new identification as new eNB UE S1AP ID for RN and UE, RN-MME allocates S1 interface new identification new MME UE S1AP ID for RN, and MME (UE-MME) serving the UE allocates S1 interface new identification new UE S1AP ID for UE.

Step 703: the RN-MME sends a handover request to the T-DeNB, and the message contains the existing information regarding the RN as the UE. If the RN-MME is changed, the old MME needs to forward the message to the target MME, and the process of forwarding the message by the two MMEs is omitted. The RN includes as the existing information of the UE:

identification of new S1 interface of RN between T-DeNB and RN-MME: new MME UES 1AP ID. This identity may reuse the identity allocated by the MME for the UE on the old S1 interface if the RN-MME has not changed. If the MME changes, the new MME will assign a new UE identity.

-handover type, where handover type is a handover type of a mobile relay.

-containers for transparent transmission of source to destination.

-list of E-RAB information to be established, e.g. E-RAB identity, uplink TEID and transport layer address allocated by the RN-GW, Qos information.

The handover request message also contains information of the UE served by the RN. This information is included to establish a tunnel for transmitting data for the UE between the gateway (SGW and PGW, RN-GW in the figure) of the RN and the T-DeNB. The information of the UE comprises the identification and the tunnel information of the UE:

identification of UE on old S1 interface between S-DeNB and UE-MME: MME UE S1 APID; eNB UE S1AP ID; (may contain only one of the identifiers).

An identity of the UE, e.g. a temporary identity S-TMSI of the UE.

List of E-RAB information of the UE, e.g. E-RAB identity, uplink TEID and transport layer address allocated by the RN-GW, Qos information.

Through the steps, the T-DeNB receives the uplink tunnel information distributed by the RN-GW for the UE before the mobile RN is switched.

Step 704: and the T-DeNB sends a switching response message to the RN-MME. The message contains existing information regarding the RN as a UE. The RN includes as the existing information of the UE:

identification of new S1 interface of RN between T-DeNB and RN-MME: new MME UES 1AP ID, new eNB UE S1AP ID.

-a container for transparent transmission of destination to source.

-a list of successfully established E-RAB information, including E-RAB information such as E-RAB identity, downlink TEID assigned by T-DeNB and transport layer address.

The handover response message also contains information of the UE served by the RN. This information is included in order to establish a tunnel for transmitting data for the UE between the gateway (SGW and PGW) of the RN and the T-DeNB. The UE information includes the S1 interface new identifier and tunnel information of the UE (the UE information may include one or more or all of the following), specifically:

identification of new S1 interface of UE between T-DeNB and UE-MME: new eNB UE S1AP ID;

identification of UE on old S1 interface between S-DeNB and UE-MME: MME UE S1 APID, eNB UE S1AP ID;

-an identity of the UE, e.g. a temporary identity of the UE, S-TMSI; (only one of the MME UE S1AP ID, eNB UE S1AP ID and UE ID can be included in the UE ID for the RN-MME to identify the corresponding UE);

-a list of E-RAB information for the UE, including E-RAB information such as E-RAB identity, downlink TEID assigned by the T-DeNB and transport layer address.

Through the step, the RN-MME receives the downlink tunnel information and the new S1 interface identifier allocated by the T-DeNB for the UE.

Step 705: and the RN-MME sends a switching command message to the S-DeNB. The message contains existing information regarding the RN as a UE. The RN includes as the existing information of the UE:

-a container for transparent transmission of destination to source.

-handover type, where handover type is a handover type of a mobile relay.

Step 706: and the S-DeNB sends an RRC message switching command to the RN, and the RN is switched to a target cell on the target DeNB. The messages are the same as the current RRC messages and are omitted here.

Step 707: and the RN is synchronous with the target cell and sends the uplink RRC message to complete the switching to the target DeNB. The messages are the same as the current RRC messages and are omitted here.

Step 708: the destination DeNB sends a path switch message to the RN-MME, the message containing existing information regarding the RN as the UE. The RN includes as the existing information of the UE:

identification of new S1 interface of RN between T-DeNB and RN-MME: MME UE S1 APID, eNB UE S1AP ID.

-an identity of the destination cell.

-target TAI.

Step 709: the RN-MME sends a change bearer request message to gateways (SGW and PGW) of the RN.

The change bearer request message contains existing information regarding the RN as a UE. The RN includes as the existing information of the UE:

-an E-RAB information list of the RN, containing E-RAB information, e.g. E-RAB identity, T-DeNB assigned downlink TEID, transport layer address.

The change bearer request message also contains information of the UE served by the RN. The UE information includes (one or more or all of):

-an identity of the UE, e.g. a temporary identity of the UE, S-TMSI;

E-RAB information of the UE, e.g. E-RAB identity, T-DeNB assigned downlink TEID and transport layer address.

Through this step, the RN-MME sends the downlink tunnel information allocated to the UE by the T-DeNB received in step 704 to the RN-GW.

Alternatively, step 709 may be replaced with the following two steps:

firstly, the method comprises the following steps: the RN-MME sends a change bearer request message to gateways (SGW and PGW) of the RN. The change bearer request message contains existing information regarding the RN as a UE. The RN includes as the existing information of the UE:

II, secondly: the T-DeNB sends a path update message to the RN-GW, wherein the message contains the information of the UE served by the RN. The UE information includes (the UE information may include one or more or all of the following):

-an identity of the UE, e.g. a temporary identity of the UE, S-TMSI;

Step 710: and the gateway (SGW and PGW) of the RN sends a change bearer response message to the RN-MME. The message contains information of the RN and the UE served by the RN:

an E-RAB information list of the RN, containing E-RAB information, such as E-RAB identity, TEID of the RN-GW assigned uplink, transport layer address.

-an identity of the UE, e.g. a temporary identity of the UE, S-TMSI;

E-RAB information of the UE, e.g. E-RAB identity, uplink TEID assigned by the RN-GW, transport layer address.

Like step 709, if step 709 is implemented with two messages, step 710 is also implemented with two response messages.

The response message one: and the gateway (SGW and PGW) of the RN sends a change bearer response message to the RN-MME. The message contains the information of the RN:

And a response message II: the gateways (SGW and PGW) of the RN send path update response messages to the T-DeNB. The message contains information of the UE served by the RN:

an identity of the UE, e.g. a temporary identity S-TMSI of the UE.

And when the transmission of the uplink and downlink tunnel information between the T-DeNB and the RN-GW is finished, tunnel establishment can be carried out.

Step 711: and the RN-MME sends a UE context release command message to the S-DeNB and releases the context information which is stored on the S-DeNB and has a relationship with the RN and the UE on the RN. The message contains the identities eNB S1AP ID and MME S1AP ID of the UE on the old S1, or only the MMEs 1AP ID, and the message also contains the reason for release, which differs from the presently defined message in that the message may contain context information for multiple UEs by including in the message the identities on the S1 interface for a group of UEs.

Step 712: and the S-DeNB sends a UE context release completion message to the RN-MME.

Step 713: an S1 interface is established between the RN and the T-DeNB. After handover, the T-DeNB becomes a new DeNB for the RN, which is still referred to as the T-DeNB for descriptive convenience. The RN transmits S1a setup request message to the T-DeNB. The message contains the base station identification of the RN and the TAI supported by the RN. The message also contains the information of the UE above the RN, and the information of the UE contains the following information:

-GUMMEI information of UE services.

The UE' S old S1 interface identity between RN and S-DeNB: eNB UE S1AP ID.

identification of UE on old S1 interface between S-DeNB and UE-MME: MME UE S1 APID;

-context information of the UE, such as ciphering capability of the UE, access stratum capability information, maximum rate of the UE at the S1 interface, E-RAB information to be established, RRC context, handover restriction list, location reporting information;

-other information, e.g. history information of the UE, depending on the activation information.

The information of the UE above the RN may also be transmitted to the T-DeNB through a separate message after being established at S1.

Step 714: the T-DeNB sends S1a setup response message, which contains the T-DeNB as the information that the MME should transmit to the RN:

-a list of Served GUMMEI information, GUMMEI information comprising PLMN identity, MME group identity, MME code.

-indication that MME supports RN.

-capability information of the MME.

The S1 setup response message also contains information about UEs above the RN, including

Identification of the new S1 interface of the UE between RN and T-DeNB: new eNB UE S1AP ID, new MME UE S1AP ID.

A list of E-RAB information for the UE, including E-RAB information, such as E-RAB identity, TEID and transport layer address of the uplink assigned by the T-DeNB.

In accordance with step 614, the UE information on the RN may also be sent to the T-DeNB through a separate message response after being established at S1.

And the S1 interface is established, and the tunnel information transmission between the RN and the T-DeNB is realized in the interface establishing process. Or, after the interface setup of S1 is completed, tunnel information between the RN and the T-DeNB may be transmitted.

Next, the UE identity on the UE-MME and the RN-GW is updated.

Step 715: the T-DeNB finds the service MME of the UE and sends a message to update the information of the UE stored on the service MME, wherein the message comprises

Old identity of the UE at the S1 interface between the S-DeNB and the MME: MME UE S1AP ID, eNB UE S1AP ID;

new identification of the S1 interface of the UE between the T-DeNB and the MME, new eNB UE S1AP ID

Step 716: and the serving MME of the UE sends a message to the T-DeNB to update the identity of the UE. The message may contain information of a group of UEs, the information of one UE containing:

new identity of UE S1 interface between T-DeNB and MME, new eNB UE S1AP ID, new MME UE S1AP ID.

-encryption information.

Step 717: updating the UE identity stored on the RN-GW may be accomplished in several ways.

Firstly, the method comprises the following steps: the T-DeNB sends an information updating message to the RN-GW, wherein the message comprises:

old identity of the UE at the S1 interface between the S-DeNB and the MME: MME UE S1AP ID, eNB UE S1AP ID. (ii) a

New identity of UE at S1 interface between T-DeNB and MME: new MME UE S1 APID, new eNB UE S1AP ID.

II, secondly: UE-MME sends information updating information to RN-GW, the information includes:

new identity of UE S1 interface between T-DeNB and MME, new MME UE S1AP ID, new eNB UE S1AP ID.

In the above procedure, the corresponding information may include old S1 interface identifier (MME UEs 1AP ID, eNB UEs S1AP ID) of the UE and/or unique UE identifier (e.g. temporary UE identifier), which are collectively referred to as UE identifier, and is used to identify the corresponding UE.

Example two

Embodiment two is a flowchart of the RN switching to the destination DeNB through the S1 interface. The S/P GW of the RN is not changed. After the RN switching process, a tunnel used for transmitting data between the S/PGW of the RN and the T-DeNB is established for the UE, and a tunnel used for transmitting data is established between the RN and the T-DeNB. The RN is switched to the destination DeNB, and the MME served by the RN can also be switched to the new MME. Embodiment two serving MME with RN is not changed to example. It also involves the forwarding of messages between the source MME and the destination MME if the serving MME of the RN changes. Fig. 8 omits messages between the source MME and the destination MME. The following is a detailed description of fig. 8:

step 801: the RN measures the surrounding radio environment and transmits a measurement report to a serving DeNB (S-DeNB in the drawing). Based on the measurement report, the DeNB decides to switch the RN to the destination DeNB (T-DeNB in the figure) with better signal quality.

Step 802: the S-DeNB sends a handover required message to a serving MME of the RN, namely the RN-MME in the figure, wherein the handover required message comprises the existing information taking the RN as the UE. The RN includes as the existing information of the UE:

-handover type, where handover type is a handover type of a mobile relay.

-destination address of handover, here identity of T-DeNB of handover destination, whereby identity MME can find T-DeNB.

Containers for transparent transmission of source to destination

The message also contains information of the UE served by the RN. Some information of the UE served by the RN needs to be handed over to the destination DeNB during the handover process, and may include information of a plurality of UEs, where the information of each UE includes (the information of the UE may include one or more or all of the following):

identification of the S1 interface of the UE between the S-DeNB and the UE-MME: eNB UE S1AP ID, MME UE S1AP ID;

-context information of the UE, such as ciphering capability of the UE, access stratum capability information, maximum rate of the UE at the S1 interface, E-RAB information to be established; RRC context, handover restriction list, location reporting information.

Step 803: the RN-MME sends a handover request to the T-DeNB, and the message contains the existing information regarding the RN as the UE. If the RN-MME is changed, the old MME needs to forward the message to the target MME, and the process of forwarding the message by the two MMEs is omitted. The RN includes as the existing information of the UE:

-handover type, where handover type is a handover type of a mobile relay.

-containers for transparent transmission of source to destination.

Step 804: and the T-DeNB sends a switching response message to the RN-MME. The message contains existing information regarding the RN as a UE. The RN includes as the existing information of the UE:

-a container for transparent transmission of destination to source.

Step 805: and the RN-MME sends a switching command message to the S-DeNB. The message contains existing information regarding the RN as a UE. The RN includes as the existing information of the UE:

identification of new S1 interface of RN between T-DeNB and RN-MME: new MME UES 1AP ID, new eNB UE S1AP ID;

-a container for transparent transmission of destination to source.

-handover type, where handover type is a handover type of a mobile relay.

Step 806: and the S-DeNB sends an RRC message switching command to the RN, and the RN is switched to a target cell on the target DeNB. The messages are the same as the current RRC messages and are omitted here.

Step 807: and the RN is synchronous with the target cell and sends the uplink RRC message to complete the switching to the target DeNB. The messages are the same as the current RRC messages and are omitted here.

Step 808: the destination DeNB sends a path switch message to the RN-MME, the message containing existing information regarding the RN as the UE. The RN includes as the existing information of the UE:

-an identity of the destination cell.

-target TAI.

Step 809: the RN-MME sends a change bearer request message to gateways (SGW and PGW) of the RN. The change bearer request message contains existing information regarding the RN as a UE. The RN includes as the existing information of the UE:

Step 810: and the gateway (SGW and PGW) of the RN sends a change bearer response message to the RN-MME. The change bearer response message contains existing information regarding the RN as the UE. The RN includes as the existing information of the UE:

-an E-RAB information list of the RN, including E-RAB information, e.g. E-RAB identity, TEID of uplink allocated by the RN SGW, transport layer address.

Step 811: and the RN-MME sends a UE context release command message to the S-DeNB and releases the context information which is stored on the S-DeNB and related to the RN. The message contains the identity of the RN and the reason for the release.

Step 812: and the S-DeNB sends a UE context release completion message to the RN-MME.

By step 812, the RN ends the handover procedure as a UE. In the above steps, tunnel information for transmitting RN data and radio bearer information of the Un interface between the RN and the DeNB are established between the T-DeNB and the RN-GW, but tunnel information for UE user data is not transmitted, and the tunnel information for the UE is transmitted after the handover is completed.

Step 813: an S1 interface is established between the RN and the T-DeNB. After handover, the T-DeNB becomes a new DeNB for the RN, and for convenience of description, it is still called as the T-DeNB. The RN transmits S1a setup request message to the T-DeNB. The message contains the base station identification of the RN and the TAI supported by the RN. The message also contains information of the UE above the RN, which contains the following information, (which may be one or more or all):

the UE' S old S1 interface identity between RN and S-DeNB: MME UE S1AP ID, eNB UE S1AP ID;

new S1 interface identification of UE between RN and T-DeNB: new eNB UE S1AP ID;

-GUMMEI information of UE services.

-identity of the UE, e.g. S-TMSI.

-other information, e.g. history information of the UE, depending on the activation information. The information of the UE above the RN may also be transmitted to the T-DeNB through a separate message after being established at S1.

Step 814: the T-DeNB sends S1a setup response message, which contains the T-DeNB as the information that the MME should transmit to the RN:

-indication that MME supports RN.

-capability information of the MME.

And the S1 interface is established, and the tunnel information transmission between the RN and the T-DeNB is realized in the interface establishing process.

In accordance with step 813, the UE information may also be sent to the RN through a separate response message established by the S1 interface.

It is noted that the 813 step and the 814 step can be used as separate processes and in combination with other methods, and are not limited to be used in combination with the steps in the present embodiment.

Step 815: the T-DeNB finds the service MME of the UE, sends a path switching request message to update the information of the UE stored on the service MME, and the message comprises

Old identity of the UE at the S1 interface between the S-DeNB and the MME: eNB UE S1AP ID, MME UE S1AP ID;

new identity of UE at S1 interface between T-DeNB and MME: new eNB UE S1 APID;

-a list of E-RAB information for the UE, including E-RAB information, e.g. E-RAB identity, T-DeNB assigned downlink TEID, transport layer address;

-address of RN GW.

Step 816: the UE-MME sends a request message for changing the bearing or a request message for establishing the bearing to a gateway of the RN, wherein the message comprises information of a group of UEs, and the information of each UE comprises:

-identity of the UE, e.g. S-TMSI of the UE.

Identification of the S1 interface of the UE between the S-DeNB and the UE-MME: new eNB S1AP ID, MME S1AP ID;

new identity of UE at S1 interface between T-DeNB and MME: new eNB UE S1 APID;

-a list of E-RAB information for the UE to be established, including E-RAB information, e.g. E-RAB identity, T-DeNB assigned downlink TEID, transport layer address.

Step 817: the gateway of the RN sends a bearer change response message to the UE-MME, the message comprises information of a group of UEs, and the information of each UE comprises:

-identity of the UE, e.g. S-TMSI of the UE.

-identity of the UE S1 interface between S-DeNB and UE-MME, eNB S1AP ID, MME S1AP ID.

New identity of UE S1 interface between T-DeNB and MME, new eNB UE S1AP ID, new MME S1AP ID.

-a list of E-RAB information for the UE to be established, including E-RAB information, e.g. E-RAB identity, uplink TEID assigned by RN GW, transport layer address.

Step 818: and the UE-MME sends a response message to the T-DeNB. Message containing

-identity of the new S1 interface of the UE between the T-DeNB and MME, new eNB UE S1AP ID, new MME UE S1AP ID.

-encryption information.

-UE E-RAB information list containing E-RAB information, e.g. E-RAB identity, RN GW assigned uplink TEID, transport layer address.

Step 815 + 818 realizes the transmission of the UE tunnel information between the T-DeNB and the RN-GW, so that the tunnel between the T-DeNB and the RN-GW may be established for transmitting the UE information.

Similarly to the first embodiment, the corresponding information of the above procedure may include old S1 interface identifiers (MME UE S1AP ID, eNB UE S1AP ID) of the UE and/or unique UE identifiers (e.g. temporary UE identifiers), which are collectively referred to as UE identifiers, and is used to identify the corresponding UE.

EXAMPLE III

Fig. 9 is a flowchart of the RN switching to the destination DeNB through the X2 interface. The S/P GW of the RN is not changed. In the process of RN switching, a tunnel for transmitting data between the S/PGW and the T-DeNB of the RN is established for the UE. The following is a detailed description of fig. 9:

step 901: the RN measures the surrounding radio environment and transmits a measurement report to a serving DeNB (S-DeNB in the drawing). According to the measurement report, the DeNB decides to switch the RN to a destination DeNB (T-DeNB in the figure) with better signal quality, an established X2 interface between the S-DeNB and the T-DeNB, and the S-DeNB initiates an X2 switch.

Step 902: the S-DeNB sends a handover request message to the T-DeNB, wherein the handover request message contains the existing information which takes the RN as the UE. The RN includes as the existing information of the UE:

-old UE identity of RN on S-DeNB: old eNB UE X2 AP ID;

handover cause, where handover cause is handover of a mobile relay.

-destination address of handover, where identity of the handover destination cell.

-identity of MME GUMMEI.

-RRC context

-information of the E-RAB to be established, e.g. E-RAB identity, TEID and transport layer address of the uplink allocated by the RN-GW, Qos information.

The handover request message also contains information of the UE served by the RN. The information of the UE may also be transmitted through a separate handover request message, and the information includes information of one or more UEs, and the information is included in order to establish a tunnel for transmitting data for the UE between the gateway (SGW and PGW) of the RN and the T-DeNB. The UE information includes UE identity and tunnel information (the UE information may include one or more or all of the following):

old UE identity of UE on S-DeNB: old eNB UE X2 AP ID;

-identity of MME of UE GUMMEI.

-context information of the UE, such as ciphering capability of the UE, access stratum capability information, maximum rate of the UE at the S1 interface, RRC context, handover restriction list, location reporting information.

In this embodiment, the UE identifier may be an old identifier eNB UE S1AP ID of an S1 interface, an MME UE S1AP ID, and an old identifier old eNB UE X2 AP ID of the UE on the S-DeNB, and may include one or any combination of the above identifiers in the message for identifying the corresponding UE. Generally, the old UE identity appearing in the subsequently sent message is the same as the UE identity of this step.

Step 903: the T-DeNB sends a handover response message to the S-DeNB, the message containing existing information regarding the RN as the UE. The RN includes as the existing information of the UE:

-new identity of RN at T-DeNB: new eNB UE X2 AP ID.

-old UE identity of RN on S-DeNB: old eNB UE X2 AP ID;

-the accepted E-RAB information comprises an E-RAB identification, an IP address of the T-DeNB and a tunnel identification, and is used for receiving the data sent by the RN-GW.

-a container for transparent transmission of destination to source.

The handover response message also contains information of the UE served by the RN. The information of the UE includes:

new identity of UE in T-DeNB: new eNB UE X2 AP ID.

Old UE identity of UE on S-DeNB: old eNB UE X2 AP ID;

Through the steps, the T-DeNB receives and receives the uplink tunnel information distributed by the RN-GW for the UE before the RN is switched, and the T-DeNB also distributes a tunnel for receiving downlink data to the user data.

Step 904: and the S-DeNB sends an RRC message switching command to the RN, and the RN is switched to a target cell on the target DeNB. The messages are the same as the current RRC messages and are omitted here.

Step 905: and the RN is synchronous with the target cell and sends the uplink RRC message to complete the switching to the target DeNB. The messages are the same as the current RRC messages and are omitted here.

Step 906: the destination DeNB sends a path switching request message to the RN-MME, wherein the message contains the existing information which takes the RN as the UE. The RN includes as the existing information of the UE:

identification of new S1 interface of RN between T-DeNB and RN-MME: new eNB UE S1AP ID

Identification of the old S1 interface of the RN between the S-DeNB and the RN-MME: MME UE S1 APID

E-RAB information for handover, e.g. E-RAB identity, T-DeNB assigned downlink TEID and transport layer address.

-destination cell identity.

-target TAI.

The path switch request message further includes information of UEs on the RN, which may include information of one or more UEs, where the information of each UE includes:

identification of UE on old S1 interface between S-DeNB and UE-MME: MME UE S1 APID, eNB UE S1AP ID.

-E-RAB information for handover. E.g., E-RAB identification, T-DeNB assigned downlink TEID and transport layer address.

Through the step, the RN-MME receives the downlink tunnel information distributed by the T-DeNB for the UE.

Step 907: the RN-MME sends a change bearer request message to gateways (SGW and PGW) of the RN. The change bearer request message contains existing information regarding the RN as a UE. The RN includes as the existing information of the UE:

-an identity of the RN. It can be a temporary identity, such as P-TMSI, allocated by the RN-MME to the RN.

The message also contains information of the UE served by the RN, which contains:

-an identity of the UE, e.g. a temporary identity P-TMSI of the UE.

Through this step, the RN-MME sends the downlink tunnel information allocated to the UE by the T-DeNB received in step 906 to the RN-GW.

Step 908: and the gateway (SGW and PGW) of the RN sends a change bearer response message to the RN-MME.

The message contains existing information regarding the RN as a UE. The RN includes as the existing information of the UE:

Identification of new S1 interface of RN between T-DeNB and RN-MME: new eNB UE S1AP ID.

An identity of the UE, e.g. a temporary identity S-TMSI of the UE.

Step 909: and the RN-MME sends a path switching confirmation message to the T-DeNB. The message contains the information of the RN and the identification of the UE, and carries the information. The RN includes as the existing information of the UE:

identification of new S1 interface of RN between T-DeNB and RN-MME: new eNB UE S1AP ID, new MME UE S1AP ID.

The information of the UE includes:

An identity of the UE, e.g. a temporary identity S-TMSI of the UE.

Step 910: and the RN-MME sends a UE context release command message to the S-DeNB and releases the context information which is stored on the S-DeNB and related to the RN. The message contains the identity of the UE and the reason for the release. Or the RN identification is contained, and the S-DeNB deletes the RN information and the UE information served by the RN together after receiving the RN identification.

Step 911: and the S-DeNB sends a UE context release completion message to the RN-MME.

Step 912: an S1 interface is established between the RN and the T-DeNB. After handover, the T-DeNB becomes a new DeNB for the RN, and for convenience of description, it is still called as the T-DeNB. The RN transmits S1a setup request message to the T-DeNB. The message contains the base station identification of the RN and the TAI supported by the RN. The message also contains information of the UE above the RN, which contains the following information, (which may be one or more or all):

the UE' S old S1 interface identity between RN and S-DeNB: eNB UE S1AP ID.

-GUMMEI information of UE services.

Identification of UE on old S1 interface between S-DeNB and UE-MME: new MME UES 1AP ID, new eNB UE S1AP ID.

Step 913: the T-DeNB sends S1a setup response message, which contains the T-DeNB as the information that the MME should transmit to the RN:

-indication that MME supports RN.

-capability information of the MME.

Identification of the new S1 interface of the UE between RN and T-DeNB: eNB UE S1AP ID, MME UE S1AP ID.

And the S1 interface is established, and the tunnel information transmission between the RN and the T-DeNB is realized in the interface establishing process. Next, the UE identity on the UE-MME and the RN-GW is updated.

Step 914: the T-DeNB finds the service MME of the UE and sends a message to update the information of the UE stored on the service MME, wherein the message comprises

Old identity of the UE at the S1 interface between the S-DeNB and MME, eNB UE S1AP ID, MME UE S1AP ID.

New identity of UE S1 interface between T-DeNB and MME, new eNB UE S1 APID.

Step 915: UE-MME sends a change bearing request message to a gateway of RN, wherein the message comprises:

an identity of the UE, e.g. a temporary identity S-TMSI of the UE.

Identification of the UE on the old S1 interface between SeNB and UE-MME: eNB UE S1AP ID, MME UE S1AP ID.

Step 916: the gateway of the RN sends a bearer change response message to the UE-MME, wherein the message comprises:

-an identity of the UE, e.g. a temporary identity P-TMSI of the UE.

Step 917: and the UE-MME sends a response message to the T-DeNB. Message containing

-encryption information.

Similarly to the embodiment, in the above procedure, the corresponding information includes old identifiers of the S1 interface of the UE (MME UE S1AP ID, eNB UE S1AP ID), old identifiers of the UE on the S-DeNB (old nb UE X2 AP ID) and/or unique identifiers of the UE (e.g. temporary identifiers of the UE), which are collectively referred to as UE identifiers, and is used to identify the corresponding UE.

Example four

Fig. 10 is a flowchart of the RN switching to the destination DeNB through the X2 interface. The S/P GW of the RN is not changed. After the RN switching process, a tunnel for transmitting data between the S/PGW and the T-DeNB of the RN is established for the UE. The following is a detailed description of fig. 10:

step 1001: the RN measures the surrounding radio environment and transmits a measurement report to a serving DeNB (S-DeNB in the drawing). According to the measurement report, the DeNB decides to switch the RN to a destination DeNB (T-DeNB in the figure) with better signal quality, an established X2 interface between the S-DeNB and the T-DeNB, and the S-DeNB initiates an X2 switch.

Step 1002: the S-DeNB sends a handover request message to the T-DeNB, wherein the handover request message contains the existing information which takes the RN as the UE. The RN includes as the existing information of the UE:

-old UE identity of RN on S-DeNB: old eNB UE X2 AP ID;

-handover reason.

-identity of MME GUMMEI.

-RRC context

-information of E-RABs to be established, e.g. E-RAB identity, TEID and transport layer address of the uplink allocated by the RN-PGW, Qos information.

The message also contains information of the UE served by the RN. Some information of the UE served by the RN needs to be handed over to the destination DeNB during the handover process, and may include information of a plurality of UEs, where the information of each UE includes:

Step 1003: the T-DeNB sends a handover message to the S-DeNB, the message containing existing information regarding the RN as a UE. The RN includes as the existing information of the UE:

-new identity of RN at T-DeNB: new eNB UE X2 AP ID.

-old UE identity of RN on S-DeNB: old eNB UE X2 AP ID;

-accepted E-RAB information comprising E-RAB identification.

-a container for transparent transmission of destination to source.

In the above steps, the tunnel information of the RN is transmitted between the T-DeNB and the RN-GW, but the tunnel information of the UE is not transmitted, and the tunnel information of the UE is transmitted after the handover is completed.

Step 1004: and the S-DeNB sends an RRC message switching command to the RN, and the RN is switched to a target cell on the target DeNB. The messages are the same as the current RRC messages and are omitted here.

Step 1005: and the RN is synchronous with the target cell and sends the uplink RRC message to complete the switching to the target DeNB. The messages are the same as the current RRC messages and are omitted here.

Step 1006: the destination DeNB sends a path switching request message to the RN-MME, wherein the message contains the existing information which takes the RN as the UE. The RN includes as the existing information of the UE:

Identification of new S1 interface of RN between S-DeNB and RN-MME: new MME UES 1AP ID

-destination cell identity.

-target TAI.

Step 1007: the RN-MME sends a change bearer request message to gateways (SGW and PGW) of the RN. The change bearer request message contains existing information regarding the RN as a UE. The RN includes as the existing information of the UE:

Step 1008: and the gateway (SGW and PGW) of the RN sends a change bearer response message to the RN-MME.

Step 1009: and the RN-MME sends a UE context release command message to the S-DeNB and releases the context information which is stored on the S-DeNB and related to the RN. The message contains the identity of the UE and the reason for the release.

Step 1010: and the S-DeNB sends a UE context release completion message to the RN-MME.

Step 1011: an S1 interface is established between the RN and the T-DeNB. After handover, the T-DeNB becomes a new DeNB for the RN, and for convenience of description, it is still called as the T-DeNB. The RN transmits S1a setup request message to the T-DeNB. The message contains the base station identification of the RN and the TAI supported by the RN. The message also contains the information of the UE above the RN, and the information of the UE contains the following information:

the UE' S old S1 interface identity between RN and S-DeNB: eNB UE S1AP ID.

-GUMMEI information of UE services.

-context information of the UE, such as ciphering capability of the UE, access stratum capability information, maximum rate of the UE at the S1 interface, E-RAB information to be established; RRC context, handover restriction list, location reporting information,

Step 1012: the T-DeNB sends S1a setup response message, which contains the T-DeNB as the information that the MME should transmit to the RN:

-indication that MME supports RN.

-capability information of the MME.

Step 1013: the T-DeNB finds the service MME of the UE and sends a message to update the information of the UE stored on the service MME, wherein the message comprises

Old identity of the UE at the S1 interface between the S-DeNB and MME, eNB UE S1AP ID, MME UE S1AP ID. (may contain only the MME UE S1AP ID).

New identity of UE S1 interface between T-DeNB and MME, new eNB UE S1 APID.

A list of E-RAB information for the UE, including E-RAB information, e.g. E-RAB identity, TEID for T-DeNb assignment downlink, transport layer address.

Step 1014: the UE-MME sends a change bearer request message to the gateway of the RN, the message containing (one or more or all of):

an identity of the UE, e.g. a temporary identity S-TMSI of the UE.

-a list of E-RAB information for the UE, including E-RAB information, e.g. E-RAB identity, downlink TEID assigned by T-DeNB, transport layer address.

Step 1015: the gateway of the RN sends a bearer change response message to the UE-MME, wherein the message comprises:

-an identity of the UE, e.g. a temporary identity P-TMSI of the UE.

Step 1016: and the UE-MME sends a response message to the T-DeNB. Message containing

-encryption information.

The foregoing step 1013-1016 realizes the transmission of the UE tunnel information between the T-DeNB and the RN-GW, so that the tunnel between the T-DeNB and the RN-GW may be established for transmitting the data of the UE.

Similarly to the third embodiment, in the above procedure, the corresponding information includes old S1 interface identifiers of the UE (MME UE S1AP ID, eNB UE S1AP ID), old UE identifiers on the S-DeNB (old nb UE X2 AP ID) and/or unique UE identifiers (e.g. temporary UE identifiers), which are collectively referred to as UE identifiers, and is used to identify the corresponding UE.

By the method, the UE tunnel establishment between the T-DeNB and the RN-GW can be realized during the switching process of the mobile RN or after the switching is completed, and the UE tunnel establishment is used for transmitting the UE information; meanwhile, the tunnel information between the RN and the T-DeNB is transmitted while the RN is established at S1. In the above flow, the bearer information between the RN and the UE is not changed all the time, so even if the RN moves and performs handover, the handover process is transparent to the UE and can ensure continuous transmission of data.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. A method for establishing a tunnel between a DeNB of a mobile relay and a gateway of the mobile relay, wherein when the mobile Relay (RN) is handed over to a new DeNB through an S1 interface, the method comprises the following steps:

2. The method according to claim 1, wherein the step D is: the RN-MME sends a request for changing the bearing establishment to the RN-GW, wherein the message contains an S1 interface new identifier and downlink tunnel information which are distributed by the target DeNB for each UE served by the mobile RN;

or,

3. The method of claim 1, wherein after step D, the method further comprises step E: the RN-MME sends a UE context release command message to the source DeNB, wherein the message contains the identification of all UE served by the mobile RN, and the source DeNB releases the context information of the mobile RN and the context information of all UE served by the mobile RN after receiving the UE context release command message.

4. The method of claim 3, wherein after step E, the method further comprises: and establishing an S1 interface between the mobile RN and the destination DeNB, and keeping the context information of all the UE served by the mobile RN unchanged.

5. The method of claim 1, wherein after the S1 handover is completed, the method further comprises:

6. The method according to any of claims 1 to 5, wherein the handover required message of step A further includes information that the mobile RN is a UE, and includes an S1 interface old identifier of the mobile RN between a source DeNB and an RN-MME;

7. A method for establishing a tunnel between a DeNB and a mobile relay gateway of a mobile relay, wherein when the mobile Relay (RN) is handed over to a new DeNB through an X2 interface, the method comprises the following steps:

8. The method of claim 7, wherein after step C, the method further comprises step D: the RN-MME sends a UE context release command message to the source DeNB, wherein the message contains the identification of all UE served by the mobile RN, and the source DeNB releases the context information of the mobile RN and the context information of all UE served by the mobile RN after receiving the UE context release command message.

9. The method of claim 8, wherein after step D, the method further comprises: and establishing an S1 interface between the mobile RN and the destination DeNB, and keeping the context information of all the UE served by the mobile RN unchanged.

10. The method of claim 1, wherein after the X2 handover is completed, the method further comprises:

11. The method according to any of claims 7 to 10, wherein the handover request message of step a further includes information that the mobile RN is a UE, wherein the information includes an old identifier of the mobile RN on a source DeNB and uplink tunnel information allocated by the RN-GW to the mobile RN;

12. A method for establishing a tunnel between a DeNB of a mobile relay and the mobile relay, wherein after the mobile Relay (RN) is handed over to a new DeNB, the method comprises the following steps:

13. The method according to claim 12, wherein the S1 setup request message of step a further includes a base station identity and supported TAI text information of the mobile RN;

14. A method for establishing a tunnel between a DeNB of a mobile relay and a mobile relay gateway, wherein after the mobile Relay (RN) is handed over to a new DeNB, the method comprises:

15. The method of claim 14, wherein step a is: the DeNB sends a path switching request message to the UE-MME, the UE-MME sends a bearer change request message to the RN-GW, and the path switching request message and the bearer change request message comprise an S1 interface new identifier and downlink tunnel information distributed by the DeNB for corresponding UE;

16. The method according to claim 15, wherein the change bearer request message in step a further includes an S1 interface new identifier allocated by the UE-MME to the corresponding UE;

17. The method as claimed in claim 14, 15 or 16, wherein when the mobile RN is handed over to the DeNB through S1, before the S1 handover is completed, the method further comprises:

18. The method as claimed in claim 14, 15 or 16, wherein when the mobile RN is handed over to the DeNB through X2, before the X2 handover is completed, the method further comprises: