CN102724722B - A kind of switched system, method, device and relevant device - Google Patents

Abstract

The invention discloses a switching system, method, device and related equipment, which are used to reduce the overhead of relay processing resources, reduce switching delay and improve switching efficiency. Wherein, the handover system includes: a relay and at least two donor base stations of the relay, wherein: the donor base station is configured to select a target base station for the user terminal to perform handover when the user terminal needs to perform handover, Sending a first handover instruction message to the relay that manages the user terminal; the relay is configured to determine that the target base station is its own donor base station according to the base station identification information carried in the received first handover instruction message , sending a second handover instruction message to the user terminal, instructing the user terminal to maintain the connection with the relayed data channel according to the connection maintenance identification information carried in the second handover instruction message, and according to the The base station identification information switches the control channel to the target base station.

Description

A switching system, method, device and related equipment

technical field

The present invention relates to the field of mobile communication, in particular to a switching system, method, device and related equipment.

Background technique

A relay (RS, RelayStation) is an intermediate node added between a base station and a user terminal (UE, UserEquipment). The relay processes the transmission signal sent by the base station, and then forwards it to the UE. According to the implementation strategy, relays can be divided into Type I (TypeI) relays and Type II (TypeII) relays.

In the existing Type II relay system, one relay corresponds to one base station, or multiple relays correspond to one base station. The base station corresponding to the relay can be called the host base station of the relay. In the prior art, a relay can only correspond to A host base station. As shown in Figure 1, it is a schematic diagram of the relationship between TypeII relays and base stations in the prior art, assuming that each base station has at least one terminal at the edge of the cell (UE1 belongs to base station 1, that is, base station 1 is the serving base station of UE1 ; UE2 belongs to base station 2, that is, base station 2 is the serving base station of UE2), base station 1 is the host base station of relay 1, and base station 2 is the host base station of relay 2. Base station 1 and base station 2 send the data channel to relay 1 and relay 2 respectively; relay 1 and relay 2 forward the data channel to UE1 and UE2 respectively. The control channels of UE1 and UE2 are directly sent by base station 1 and base station 2 to UE1 and UE2 respectively. When UE1 is far away from base station 1 and close to base station 2, the communication cannot be completed due to the serious degradation of the quality of the control channel and data channel. At this time, the problem of poor quality of the control channel and data channel can be solved by handover.

As shown in FIG. 2, it is a schematic flow diagram of UE handover in the prior art, including the following steps:

S201, the UE measures the Reference Signal Received Power (RSRP, ReferenceSignalReceivingPower) of the signal sent by the base station 1 and neighboring base stations adjacent to the base station 1, and the serving base station of the UE is the base station 1, then the base station 1 is the source base station when the UE performs handover ;

S202. When the RSRP of signals sent by base station 1 and neighboring base stations adjacent to base station 1 meets the reporting condition, the UE reports the measured RSRP of signals sent by neighboring base stations adjacent to base station 1 to relay 1;

S203. The relay 1 forwards the received RSRP to the base station 1;

S204, the base station 1 selects the target base station to which the UE will handover according to the received RSRP (for the convenience of description, it is assumed that the selected target base station is the base station 2);

S205. Base station 1 sends a handover request to base station 2;

S206. Base station 2 returns a handover confirmation message to base station 1;

S207. Base station 1 sends a handover instruction message to relay 1;

S208. The relay 1 forwards the received handover indication message to the UE;

S209, the UE terminates the connection with the relay 1, and sends an uplink synchronization signal to the base station 2;

S210, the base station 2 sends a feedback signal of the uplink synchronization signal to the UE, and the feedback signal carries the uplink resources allocated for the UE1 and an advance time (TA, TimeAdvanced) value;

S211. The UE sends a handover completion message to the base station 2.

After the handover is completed, the UE establishes a connection with the base station 2, and will forward the data channel through the relay 2.

From the above handover process, it can be seen that during the handover process, the UE must first interrupt the data channel connection with the relay in the source base station, and then connect to the relay in the target base station after switching the control channel to the target base station. The relay of the source base station buffers the data sent to the UE by the source base station. Therefore, after switching to the target base station, the relay of the target base station needs to re-download this part of the data and forward it to the UE. In this way, the overhead of relay processing resources is increased. In addition, since the UE also needs to perform relay handover while performing handover, the handover delay is relatively large and the handover efficiency is low.

Contents of the invention

Embodiments of the present invention provide a handover system, method, device and related equipment, which are used to reduce overhead of relay processing resources, reduce handover delay, and improve handover efficiency.

An embodiment of the present invention provides a handover system, including a relay and at least two donor base stations of the relay, wherein:

The master base station is configured to select a target base station for the user terminal to perform handover when the user terminal needs to be handed over, and send a first handover indication message to a relay that manages the user terminal, and the first handover indication message includes carrying the base station identification information of the target base station;

The relay is configured to send a second handover instruction message to the user terminal when it is determined that the target base station is its own donor base station according to the base station identification information carried in the received first handover instruction message, so that The second indication message carries the base station identification information and the connection maintenance identification information, instructs the user terminal to maintain the connection with the relay data channel according to the connection maintenance identification information, and according to the base station identification information Handing over a control channel to the target base station.

An embodiment of the present invention provides a switching method, including:

The relay receives a first handover indication message sent by the source base station of the user terminal, where the first handover indication message carries the base station identification information of the target base station to which the user terminal is to be handed over;

When the relay determines that the target base station is its own donor base station according to the base station identification information of the target base station, the relay sends a second handover instruction message to the user terminal, and the second handover instruction message carries The base station identification information and the connection maintenance identification information, instructing the user terminal to maintain a connection with the relay data channel according to the connection maintenance identification information, and to switch the control channel to the target according to the base station identification information base station.

An embodiment of the present invention provides a switching device, including:

The receiving unit is configured to receive a first handover indication message sent by a source base station of the user terminal, where the first handover indication message carries base station identification information of a target base station to which the user terminal is to be handed over;

a judging unit, configured to judge whether the target base station is its own donor base station according to the base station identification information;

A first sending unit, configured to send a second handover instruction message to the user terminal when the judging result of the judging unit is yes, and the second handover instruction message carries the base station identification information and the connection maintenance identifier information, instructing the user terminal to maintain the connection with the relayed data channel according to the connection maintenance identification information, and to switch the control channel to the target base station according to the base station identification information.

An embodiment of the present invention provides a relay device, including the foregoing switching device.

An embodiment of the present invention provides a user terminal, including:

The first receiving unit is configured to receive a first handover instruction message sent by the relay, where the first handover instruction message carries the base station identification information and connection maintenance identification information of the target base station when the user terminal performs handover;

a connection maintaining unit, configured to maintain a connection with the relay data channel according to the connection maintaining identification information;

A first switching unit, configured to switch the control channel to the target base station according to the base station identification information.

In the handover system, method, device and related equipment provided by the embodiments of the present invention, when a user terminal performs handover, the source base station sends a first handover instruction message to the relay connected to the user terminal, and the handover instruction message carries the user terminal The base station identification information of the target base station to be handed over to, so that the relay can judge whether the target base station is its own donor base station according to the base station identification information of the target base station. When the judgment result is yes, the relay sends the second The handover instruction message carries the base station identification information and connection maintenance identification information of the target base station, so that the user terminal performs control channel connection while maintaining the connection with the relay data channel according to the received second handover instruction message. Handover, thereby reducing the overhead of relay processing resources, reducing the handover delay, and improving the handover efficiency.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Description of drawings

FIG. 1 is a schematic diagram of the relationship between a Type II relay and a base station in the prior art;

FIG. 2 is a schematic flow diagram of UE handover in the prior art;

FIG. 3 is a schematic diagram of the relationship between a TypeII relay and a base station in an embodiment of the present invention;

FIG. 4 is a schematic structural diagram of a switching system in an embodiment of the present invention;

FIG. 5 is a schematic diagram of an implementation flow of a handover method in an embodiment of the present invention;

FIG. 6 is a schematic diagram of an implementation flow of handover by a user terminal in an embodiment of the present invention;

FIG. 7 is a schematic diagram of a possible structure of a switching device in an embodiment of the present invention;

FIG. 8 is a schematic diagram of a possible structure of a user terminal in an embodiment of the present invention.

detailed description

In order to reduce overhead of relay processing resources, reduce handover delay during handover, and improve handover efficiency, embodiments of the present invention provide a handover system, method, device, and related equipment.

The preferred embodiments of the present invention will be described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described here are only used to illustrate and explain the present invention, and are not intended to limit the present invention, and in the absence of conflict, the present invention The embodiments and the features in the embodiments can be combined with each other.

As shown in Figure 3, a schematic diagram of the relationship between the relay and the base station provided for the implementation of the present invention, wherein, base station 1 provides services for user terminals in cell 1, cell 2, and cell 3; base station 2 provides services for cell 4, cell 5, and cell Cell 6 provides services; base station 3 provides services for user terminals in cells 7 , 8 , and 9 . The relay provides services for edge user terminals in Cell 3, Cell 5, and Cell 7, and Base Station 1, Base Station 2, and Base Station 3 are all host base stations of the relay.

As shown in FIG. 4 , it is a schematic diagram of a possible system structure of a handover system in an embodiment of the present invention, including a relay 401 and at least two donor base stations 402 of the relay, assuming that each donor base station 402 has at least one in a cell Edge user terminals. The donor base station 402 sends the data channel to the relay, and the relay forwards the data channel to the user terminal respectively; the donor base station 402 directly sends the control channel to the user terminal. in:

The host base station 402 is configured to select a target base station for the user terminal to perform handover when the user terminal needs to be handed over, and send a first handover instruction message to the relay 401 that manages the user terminal, and the first handover instruction message carries a target Base station identification information of the base station;

The relay 401 is configured to send a second handover instruction message to the user terminal when judging that the target base station is its own donor base station according to the base station identification information carried in the received first handover instruction message, in which the second handover instruction message contains Carrying the base station identification information and the connection maintenance identification information of the target base station, the second handover instruction message indicates that the user terminal maintains the connection with the data channel of the relay 401 according to the connection maintenance identification information, and controls the The channel is switched to the target base station.

In a specific implementation, the relay 401 is further configured to forward the first handover instruction message to the user terminal when judging that the target base station is not its own donor base station according to the base station identification information carried in the received first handover instruction message, Instructing the user terminal to switch the control channel to the target base station according to the base station identification information of the target base station carried in the first handover instruction message after disconnecting from its own data channel.

As shown in FIG. 5, it is a schematic diagram of the implementation flow of the handover method provided by the embodiment of the present invention, including the following steps:

S501. The relay receives the first handover indication message sent by the source base station of the user terminal, where the first handover indication message carries the base station identification information of the target base station to which the user terminal is to be handed over;

S502. According to the base station identification information of the target base station, when the relay determines that the target base station is its own donor base station, the relay sends a second handover instruction message to the user terminal, and the second handover instruction message carries the base station identification information of the target base station and the connection Keeping the identification information, instructing the user terminal to maintain the connection with the relayed data channel according to the connection keeping identification information, and to switch the control channel to the target base station according to the base station identification information of the target base station.

In the specific implementation, since the user terminal forwards the data channel with the source base station through the relay, that is, the source base station sends the user's data channel to the relay, and the relay forwards the received data channel to the user terminal, therefore, the The source base station of the user terminal must be the donor base station of the relay.

In specific implementation, in step S502, the relay judges whether the target base station is its own donor base station according to the following method:

The relay judges whether the base station identification information carried in the first handover indication message exists in the base station identification information corresponding to its own donor base station;

If the judgment result is yes, confirming that the target base station is its own donor base station;

If the determination result is no, it is confirmed that the target base station is not its own donor base station.

In a specific implementation, if the relay determines that the target base station is not its own donor base station, it forwards the received first handover instruction message to the user terminal, instructing the user terminal to terminate the connection with its own data channel, The control channel is handed over to the target base station according to the base station identification information of the target base station carried in the first handover instruction message.

In the handover method provided by the embodiment of the present invention, since one relay corresponds to multiple donor base stations, in this way, when the user terminal performs handover, if the target base station is the host base station of the relay, the user terminal does not need to interrupt the connection with the data channel of the relay In this way, the relay and the user terminal can continue to transmit data, that is, while maintaining the data channel to transmit data, complete the switching of the control channel, thereby reducing the overhead of relay processing resources, reducing the switching delay, and improving the switching efficiency .

In order to better understand the implementation manners of the embodiments of the present invention, the implementation process of the present invention will be described below through specific examples.

As shown in FIG. 6, it is a schematic diagram of the implementation flow of the handover of the user terminal in the embodiment of the present invention, including the following steps:

S601. The user terminal measures the RSRP of signals sent by the source base station and neighboring base stations adjacent to the source base station;

S602, the user terminal judges whether the RSRP of the signal sent by the source base station and neighboring base stations adjacent to the source base station meets the reporting condition, if yes, execute step S603, if not, execute step S601;

S603. Report the measured RSRPs of the signals sent by neighboring base stations adjacent to the source base station to the relay;

S604. The relay forwards the received RSRPs sent by neighboring base stations adjacent to the source base station to the source base station;

S605. The source base station selects a target base station to which the user terminal is to handover according to the received RSRP of signals sent by neighboring base stations;

S606. The source base station terminal sends a handover request to the selected target base station;

S607. The source base station receives the handover confirmation message returned by the target base station;

S608. The source base station sends a first handover indication message to the relay;

Specifically, in the first handover indication message, the base station identification information of the target base station to which the user terminal is to be handed over is carried.

S609, the relay judges whether the target base station is its own donor base station, if yes, execute step S610, if not, execute step S612;

Specifically, the relay may store in advance a list of base station identification information corresponding to its own donor base station locally, and after receiving the first handover instruction message, confirm whether the base station identification information of the target base station is in the locally stored base station corresponding to its own donor base station In the identification information list, if yes, it is confirmed that the target base station is its own donor base station; if not, it is confirmed that the target base station is not its own donor base station.

S610. The relay sends a second handover indication message to the user terminal;

Specifically, the relay carries the base station identification information and the connection maintenance identification information of the target base station in the second handover instruction message sent to the user terminal, and instructs the user terminal to maintain the connection with the data channel of the relay according to the connection maintenance identification information, And switch the control channel to the target base station according to the base station identification information of the target base station.

Specifically, the relay can set a flag bit in the second handover instruction message to instruct the user terminal to maintain a connection with its own data channel, and when the relay determines that the target base station is its own donor base station, it can set the flag bit to "1 ", instructing the user terminal to maintain the connection with its own data channel.

S611. The user terminal maintains the connection with the relayed data channel according to the connection maintenance identification information carried in the second handover indication message, and executes step S614;

S612. The relay forwards the received first handover indication message to the user terminal;

Specifically, after receiving the first handover instruction message forwarded by the relay, the user terminal interrupts the connection with the control channel of the relay, and switches the control channel to target base station.

S613. The user terminal interrupts the connection with the data channel of the relay;

S614. The user terminal switches the control channel to the target base station according to the base station identification information of the target base station.

Specifically, if the user receives the second handover instruction message sent by the relay, the user terminal maintains the connection with the data channel of the relay according to the connection maintenance identification information carried in the received second handover instruction message. In this way, the user terminal There is no need to interrupt and relay the data currently being transmitted; at the same time, send an uplink synchronization signal to the target base station according to the base station identification information of the target base station carried in the second indication information, and receive a feedback signal of the uplink synchronization signal sent by the target base station, and the feedback signal includes Indicates the uplink resource and TA value allocated for the user to send the control channel; if the user receives the first handover indication message forwarded by the relay, it will interrupt the connection with the data channel of the relay and send an uplink synchronization message to the target base station The signal receives the feedback signal of the uplink synchronization signal sent by the target base station, and the feedback signal indicates the uplink resource and TA value allocated to the user for sending the control channel.

After switching the channel of the control system to the target base station, the user terminal will send a handover completion message to the target base station. Specifically, if the target base station is the host base station of the relay, the user terminal sends a handover completion message to the relay, and the relay forwards it to the target base station; if the target base station is not the host base station of the relay, the user terminal directly sends a handover message to the target base station. Complete message. After the user terminal establishes a control channel connection with the target base station, if the user terminal interrupts the connection with the data channel of the original relay, the target base station allocates uplink resources for the user terminal to transmit the data channel. If the user terminal is located in the center of the cell, Then the target base station directly transmits the data channel to the user terminal; if the user terminal is located at the edge of the cell, the target base station forwards the data channel of the user terminal through its own relay.

Based on the same inventive concept, the embodiments of the present invention also provide a switching system, device, equipment and a user terminal. Since the problem-solving principles of these systems, devices and related equipment are similar to the switching method, these systems, devices and For the implementation of related devices, reference may be made to the implementation of the handover method above, and repeated descriptions will not be repeated.

As shown in Figure 7, it is a possible structural schematic diagram of the switching device provided by the present invention, including:

The receiving unit 701 is configured to receive a first handover indication message sent by a source base station of the user terminal, where the first handover indication message carries base station identification information of a target base station to which the user terminal is to be handed over;

A judging unit 702, configured to judge whether the target base station is its own donor base station according to the base station identification information of the target base station;

The first sending unit 703 is configured to send a second handover instruction message to the user terminal when the judgment result of the judging unit 702 is yes, the second handover instruction message carries the base station identification information and the connection maintenance identifier of the target base station The information indicates that the user terminal maintains the connection with the relayed data channel according to the connection maintenance identification information, and switches the control channel to the target base station according to the base station identification information of the target base station.

In a specific implementation, the judging unit 702 may include:

A judging subunit, configured to judge whether the base station identification information carried in the first handover instruction message exists in the base station identification information corresponding to the master base station of the handover device;

The first confirming subunit is configured to confirm that the target base station is the host base station of the handover device when the judgment result of the judging subunit is yes;

The second confirming subunit is configured to confirm that the target base station is not the host base station of the handover device when the judgment result of the judging subunit is negative.

In specific implementation, the switching device also includes:

The second sending unit 704 is configured to forward the first switching instruction message received by the receiving unit 701 to the user terminal when the judgment result of the judging unit 702 is negative, indicating that the user terminal is interrupting the connection with the relayed data channel Afterwards, the control channel is switched to the target base station according to the base station identification information of the target base station.

For the convenience of description, each part of the above switching device is divided into modules (or units) according to their functions and described separately. Certainly, when implementing the present invention, the functions of each module (or unit) can be implemented in one or more pieces of software or hardware.

In the embodiment of the present invention, the switching device is generally set in the relay device. It should be noted that setting the above-mentioned switching device in the relay device is only a preferred implementation manner, and in specific implementation, the above-mentioned switching device can be set in other devices or newly added devices according to actual needs.

As shown in FIG. 8, it is a schematic structural diagram of a possible user terminal provided by the embodiment of the present invention, including:

The first receiving unit 801 is configured to receive a first handover instruction message sent by the relay, where the first handover instruction message carries the base station identification information and the connection maintenance identification information of the target base station when the user terminal performs handover;

A connection maintaining unit 802, configured to maintain the connection with the relayed data channel according to the connection maintaining identification information;

The first switching unit 803 is configured to switch the control channel to the target base station according to the base station identification information of the target base station.

In specific implementation, the user terminal also includes:

The second receiving unit is configured to receive a second handover instruction message sent by the relay, where the second handover instruction message carries the base station identification information of the target base station when the user terminal performs handover;

a connection interrupting unit, configured to interrupt the connection with the relayed data channel according to the second handover indication message received by the second receiving unit;

The second switching unit is configured to switch the control channel to the target base station according to the base station identification information of the target base station.

In the handover system, method, device and related equipment provided by the embodiments of the present invention, when a user terminal performs handover, the source base station sends a first handover instruction message to the relay connected to the user terminal, and the handover instruction message carries the user terminal The base station identification information of the target base station to be handed over to, so that the relay can judge whether the target base station is its own donor base station according to the base station identification information of the target base station. When the judgment result is yes, the relay sends the second The handover instruction message carries the base station identification information and connection maintenance identification information of the target base station, so that the user terminal performs control channel connection while maintaining the connection with the relay data channel according to the received second handover instruction message. Handover, thereby reducing the overhead of relay processing resources, reducing the handover delay, and improving the handover efficiency.

Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

Claims (11)

1. a switched system, is characterized in that, comprises at least two host base station of relaying and this relaying, wherein:

Described host base station, during for needing to switch at user terminal, for described user terminal selecting carries out the target BS that switches, the relaying to this user terminal of management sends the first switch indicating information, carries the base station identification information of described target BS in described first switch indicating information;

Described relaying, for the base station identification information of carrying in the first switch indicating information that basis receives, when judging that described target BS is the host base station of self, the second switch indicating information is sent to described user terminal, carry described base station identification information in described second switch indicating information and keep identification information with being connected, indicate described user terminal to keep identification information to keep the connection with the data channel of described relaying according to described connection, and according to described base station identification information, control channel is switched to described target BS.

2. the system as claimed in claim 1, is characterized in that,

Described relaying, also for according to the base station identification information of carrying in the first switch indicating information of receiving, when judging that described target BS is not the host base station of self, described first switch indicating information is transmitted to described user terminal, indicate described user terminal after interruption with the connection of the data channel of described relaying, according to described base station identification information, control channel is switched to described target BS.

3. a changing method, is characterized in that, comprising:

First switch indicating information of the source base station transmission of relay reception user terminal, carries the base station identification information of the target BS that described user terminal will be switched in described first switch indicating information;

Described relaying is according to the base station identification information of described target BS, when judging that described target BS is the host base station of self, the second switch indicating information is sent to described user terminal, carry described base station identification information in described second switch indicating information and keep identification information with being connected, indicate described user terminal to keep identification information to keep the connection with the data channel of described relaying according to described connection, and according to described base station identification information, control channel is switched to described target BS.

4. method as claimed in claim 3, is characterized in that, by following method, described relaying judges that whether described target BS is self host base station:

Described relaying judges, in the base station identification information that the host base station of self is corresponding, whether to there is the base station identification information of carrying in described first switch indicating information;

If the determination result is YES, then confirm that described target BS is self host base station;

If judged result is no, then confirm that described target BS is not the host base station of self.

5. method as claimed in claim 3, is characterized in that, also comprise:

Described relaying is according to the base station identification information of described target BS, when judging that described target BS is not the host base station of self, described first switch indicating information is transmitted to described user terminal, indicate described user terminal after interruption with the connection of the data channel of described relaying, according to described base station identification information, control channel is switched to described target BS.

6. be arranged at the switching device shifter in relaying, it is characterized in that, comprising:

Receiving element, the first switch indicating information that the source base station for receiving user terminal sends, carries the base station identification information of the target BS that described user terminal will be switched in described first switch indicating information;

Judging unit, for according to described base station identification information, judges that whether described target BS is the host base station of described relaying;

First transmitting element, for when the judged result of described judging unit is for being, the second switch indicating information is sent to described user terminal, carry described base station identification information in described second switch indicating information and keep identification information with being connected, indicate described user terminal to keep identification information to keep the connection with the data channel of described relaying according to described connection, and according to described base station identification information, control channel is switched to described target BS.

7. device as claimed in claim 6, it is characterized in that, judging unit specifically comprises:

Judgment sub-unit, for judging, in the base station identification information that the host base station of described switching device shifter is corresponding, whether to there is the base station identification information of carrying in described first switch indicating information;

First confirms subelement, for when the judged result of judgment sub-unit is for being, confirms that described target BS is the host base station of described switching device shifter;

Second confirms subelement, for when the judged result of judgment sub-unit is no, confirms that described target BS is not the host base station of described switching device shifter.

8. device as claimed in claim 6, is characterized in that, also comprise:

Second transmitting element, for when the judged result of described judging unit is no, described first switch indicating information is transmitted to described user terminal, indicate described user terminal after interruption with the connection of the data channel of described relaying, according to described base station identification information, control channel is switched to described target BS.

9. a trunking, is characterized in that, comprises the switching device shifter described in the arbitrary claim of claim 6 ~ 8.

10. a user terminal, is characterized in that, comprising:

First receiving element, for receiving the first switch indicating information that relaying sends, the base station identification information carrying target BS when described user terminal switches in described first switch indicating information keeps identification information with being connected, wherein, described first switch indicating information is that described relaying judges that described target BS sends when being the host base station of self;

Connect holding unit, for keeping identification information to keep the connection with the data channel of described relaying according to described connection;

First switch unit, for being switched to described target BS according to described base station identification information by control channel.

11. user terminals as claimed in claim 10, is characterized in that, also comprise:

Second receiving element, for receiving the second switch indicating information that relaying sends, the base station identification information of target BS when described user terminal switches is carried in described second switch indicating information, wherein, described second switch indicating information is that described relaying sends when judging that described target BS is not the host base station of self;

Disconnecting unit, for interrupting the connection with the data channel of described relaying according to described second switch indicating information;

Second switch unit, for being switched to described target BS according to described base station identification information by control channel.