CN103037456A

CN103037456A - Method, associated equipment and system for controlling relay node switchover

Info

Publication number: CN103037456A
Application number: CN2011103027765A
Authority: CN
Inventors: 王可; 彭炎
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2011-10-09
Filing date: 2011-10-09
Publication date: 2013-04-10

Abstract

The invention discloses a method, associated equipment and a system for controlling relay node switchover. The method for controlling the relay node switchover comprises ensuring whether a target base station and / or a target community can support radio navigation (RN) switchover of the relay nodes through a source base station, if the target base station and / or the target community can support the RN switchover, then the source base station can switch the RN according to the RN switchover pattern. The method the associated equipment and the system for controlling the relay node switchover are beneficial for guaranteeing reliability of the RN switchover.

Description

Method, related equipment and system for controlling relay node switching

Technical Field

The present invention relates to the field of communications technologies, and in particular, to a method, a related device, and a communication system for controlling relay node handover.

Background

In a conventional network, a base station and a User Equipment (UE) communicate directly, and the network is a single-hop network with the base station as a center. After a Relay Node (RN) is introduced, communication between a base station and a UE may sometimes be performed indirectly through the RN, that is, there is a case of multi-hop transmission.

In an Evolved Universal radio access Network (E-UTRAN), an access link Uu is an air interface link between a UE and an RN, and a relay link Un is an air interface link between an RN and an Evolved base station (eNB, Evolved NB).

The working state of RN can be divided into two types: UE status and Relay status. When the RN is in the UE state, the RN does not start the Relay function, and at the moment, no UE is attached to the RN. When the RN is in the Relay state, the RN starts a Relay function, at this time, several UEs may be attached to the RN, and the RN may provide service transmission services for the attached UEs.

With the development of mobile communication technology, the RN may also have mobility, which requires that the RN can perform Handover (HO) between base stations, and therefore, how to ensure the reliability of RN Handover as much as possible is a problem to be solved.

Disclosure of Invention

The embodiment of the invention provides a method for controlling relay node switching, related equipment and a communication system, so as to ensure the reliability of RN switching.

An embodiment of the present invention provides a method for controlling relay node switching, including:

the source base station determines whether the target base station and/or the target cell support the RN switching;

and if the target base station and/or the target cell support RN switching, the source base station switches the RN according to the RN switching mode.

Another aspect of the embodiments of the present invention provides a method for controlling relay node switching, including:

the method comprises the steps that a Relay Node (RN) receives a switching command which is sent by a source base station and indicates to be switched to a target base station in an RN switching mode, wherein the switching command is sent by the source base station after the target base station and/or a target cell support RN switching;

and the RN switches to the target base station in an RN switching mode.

Another aspect of the embodiments of the present invention provides a base station, including:

a determining unit, configured to determine whether a target base station and/or a target cell supports RN handover;

and the switching control unit is used for switching the RN according to the RN switching mode when the determining unit determines that the target base station and/or the target cell supports the RN switching.

Another aspect of the embodiments of the present invention provides a relay node, including:

a receiving unit, configured to receive a handover command that is sent by a source base station and instructs to handover to a target base station in a relay node RN handover mode, where the handover command is sent by the source base station after it is determined that the target base station and/or a target cell support RN handover;

and the switching unit is used for switching to the target base station in the RN switching mode.

Another aspect of the embodiments of the present invention provides a communication system, including:

the base station according to the embodiments, or the relay node according to the embodiments.

As can be seen from the above, the source base station in the embodiment of the present invention first determines whether the target base station and/or the target cell supports the RN handover; if the target base station and/or the target cell support the RN switching, the source base station switches the RN according to the RN switching mode, and the source base station switches the RN according to the RN switching mode when the target base station and/or the target cell support the RN switching.

Drawings

Fig. 1 is a schematic diagram of a network architecture according to an embodiment of the present invention;

fig. 2 is a schematic flowchart of a relay node handover control method according to an embodiment of the present invention;

fig. 3 is a schematic flowchart of another relay node handover control method according to an embodiment of the present invention;

fig. 4 is a schematic flowchart of another relay node handover control method according to an embodiment of the present invention;

fig. 5 is a flowchart illustrating a method for a source base station to determine whether a target base station and/or a target cell supports RN handover according to an embodiment of the present invention;

fig. 6 is a flowchart illustrating a method for a source base station to determine whether a target base station and/or a target cell supports RN handover according to another embodiment of the present invention;

fig. 7 is a flowchart illustrating a method for a source base station to determine whether a target base station and/or a target cell supports RN handover according to another embodiment of the present invention;

fig. 8 is a flowchart illustrating a method for a source base station to determine whether a target base station and/or a target cell supports RN handover according to another embodiment of the present invention;

fig. 9 is a flowchart illustrating a method for a source base station to determine whether a target base station and/or a target cell supports RN handover according to another embodiment of the present invention;

fig. 10 is a schematic diagram of a base station according to an embodiment of the present invention;

fig. 11 is a schematic diagram of another base station according to an embodiment of the present invention;

fig. 12 is a schematic diagram of a relay node according to an embodiment of the present invention.

Detailed Description

The embodiment of the invention provides a method for controlling relay node switching, a related device and a communication system.

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

The following are detailed by specific examples.

Fig. 1 is a schematic diagram of a network architecture according to an embodiment of the present invention. One or more RNs, such as RN1, RN2 or RN3, may access the network through a Donor evolved base station (DeNB, Donor eNB), and the procedure of the RN accessing the network is similar to the procedure of the UE performing initial network access, that is, establishing an access link Un. In the process of accessing the network, the RN may establish a connection with a Mobility Management Entity (MME), a Serving Gateway (S-GW), and the like. The RN then activates a Relay (Relay) function so that one or more UEs, e.g., UE1, UE2, UE3, or UE4, may also access the network through the RN.

One embodiment of the method for controlling relay node switching of the present invention may include: the source base station determines whether the target base station and/or the target cell support RN switching; and if the target base station and/or the target cell support RN switching, the source base station switches the RN according to the RN switching mode.

Referring to fig. 2, a method for controlling a relay node to switch according to an embodiment of the present invention may include:

201. the source base station determines whether the target base station and/or the target cell support RN switching;

the source base station may be, for example, a DeNB in a multi-hop network; the target cell is the cell served by the target base station.

In an actual network, the RN may perform measurement reporting periodically or aperiodically, or perform measurement reporting under the trigger of a source base station or an event trigger, and if the source base station finds that the RN meets a handover condition according to the measurement reporting, for example, the channel quality of a current cell in which the RN is located drops to a set threshold, or the channel quality of a neighboring cell of the current cell in which the RN is located is better than the set threshold of the channel quality of the current cell in which the RN is located, and the like, the source base station may select whether the RN is handed over or not and a target cell to be handed over according to information reported by the handover.

The source base station may determine whether the target base station and/or the target cell supports RN handover in a variety of ways. The source base station may determine by displaying an indication, for example, whether the target base station and/or the target cell supports RN handover may be determined by type information of the target base station and/or the target cell. If the type information includes an RN handover capability indication indicating whether the target base station and/or the target cell supports RN handover, the source base station may determine whether the target base station and/or the target cell supports RN handover according to the RN handover capability indication included in the acquired type information of the target base station and/or the target cell, where the RN handover capability indication may be carried by an Information Element (IE), that is, a dedicated IE for carrying the RN handover capability indication is extended from the type information, and different RN handover capabilities may be indicated by different values. Or, the source base station may also determine whether the target base station and/or the target cell supports the RN handover in a default indication manner, for example, if an IE carrying the RN handover capability indication exists in the type information of the target base station and/or the target cell, it indicates that the target base station and/or the target cell supports the RN handover, and the source base station may determine that the target base station and/or the target cell supports the RN handover according to the IE; if the type information does not have the dedicated IE for bearing the RN handover capability indication, indicating that the target base station and/or the target cell do not support the RN handover, the source base station may determine that the target base station and/or the target cell do not support the RN handover accordingly. Or, the source base station may also determine whether the target base station and/or the target cell supports the RN handover in an implicit indication manner, for example, the source base station may indirectly indicate whether the target base station and/or the target cell supports the RN handover by using an IE which carries other information and is included in the type information of the target base station and/or the target cell, for example, an IE which is used to indicate that the type of the target base station is a DeNB or a general eNB, where if the type information includes indication information indicating that the target base station is a DeNB, the source base station may determine that the target base station supports the RN handover accordingly, and if the type information includes indication information indicating that the target base station is a general eNB, the source base station may determine that the target base station does not support the RN handover accordingly, and so on.

In the embodiment of the present invention, the source base station may obtain the type information of the target base station and/or the target cell from the target base station or other neighboring base stations. For example, the source base station may obtain type information of the target base station and/or the target cell from the target base station or other neighboring base stations based on the X2 traffic flow. Alternatively, the source base station may also obtain the type information of the target base station and/or the target cell from the MME, for example, the source base station may obtain the type information of the target base station and/or the target cell from the MME based on the S1 service flow. Alternatively, the source base station may acquire the type information of the target base station and/or the target cell from the RN, for example, the source base station may receive a measurement report message sent by the RN, where the measurement report message includes the type information of the target base station and/or the target cell. Alternatively, the source base station may also obtain a neighbor Relation list (NRT) from an Operation Administration and Maintenance (OAM) system, and obtain attribute information from the neighbor Relation list, where the attribute information may indicate whether the target base station and/or the target cell support RN handover. Alternatively, the source base station may determine whether the target base station and/or the target cell supports the RN handover by other means, which is not illustrated herein.

202. And if the target base station and/or the target cell support RN switching, the source base station switches the RN according to the RN switching mode.

In the embodiment of the present invention, the RN may perform a handover in an RN handover mode, or may perform a handover in a UE handover unit. The RN switches in the UE switching mode, that is, the RN switches in the UE state, and at this time, the RN switches in the UE identity, and does not have the Relay function. The process of the RN switching in the UE switching mode may be similar to the conventional UE switching process, and is not described herein again. The RN handover mode is different from the UE handover mode, i.e. the handover mode in which the RN performs handover in a Relay state and maintains service continuity of the UE attached to the RN during the handover process. The operation of reconfiguration of the Un interface between the RN and the target base station, context migration of the UE served by the RN, and the like can also be included in the RN handover mode.

In the embodiment of the present invention, if the source base station determines that the target base station and/or the target cell can support RN handover, the source base station may perform the RN handover according to the RN handover mode. The RN may be switched in the RN switching mode by the source base station based on different interfaces, and it can be understood that the manner in which the RN is switched in the RN switching mode by the source base station may be various, as long as the RN can be switched in the Relay state and the service continuity of the UE attached to the RN is maintained in the switching process.

For example, the procedure of handing over the RN in the RN handover mode based on the X2 interface may include: firstly, a source base station initiates a switching request to a target base station, wherein the switching request can carry the context information of an RN and the context information of UE attached to the RN; the target base station sends a switching request confirmation to the source base station; a source base station switches a command to the RN to indicate the RN to switch; after the RN is switched to the target base station, a relay link between the RN and the target base station is established; the target base station instructs the MME to transfer the S1 path of the RN and the attached UE under the RN from the source base station to the target base station.

It should be noted that, in the RN handover mode, the RN may also be handed over from the source base station to the target base station in other various manners, which is not illustrated here.

If the target base station and/or the target cell do not support RN handover, the source base station may handover the RN according to the UE handover mode, that is, the RN is used as the UE for handover, or the source base station may not handover the RN to the target base station or the target cell. The source base station may, for example, choose not to switch the RN on its own, or may reselect to switch the RN to other target cells that support the RN's handover.

As can be seen from the above, the source base station of this embodiment first determines whether the target base station and/or the target cell supports the RN handover; if the target base station and/or the target cell support the RN switching, the source base station switches the RN according to the RN switching mode, and the source base station switches the RN according to the RN switching mode when the target base station and/or the target cell support the RN switching.

In the above embodiments, the description is mainly given by taking as an example that the source base station first determines whether the target base station and/or the target cell supports the RN handover, and if so, the source base station may perform a handover control mechanism for the RN according to the RN handover mode. Another handover control mechanism is introduced below, where the source base station may not determine whether the target base station and/or the target cell supports the RN handover, but may default that the target base station and/or the target cell supports the RN handover, and initiate the RN handover, and the target base station controls the subsequent handover process of the RN according to whether the target base station and/or the target cell supports the RN handover.

An embodiment of the present invention provides another method for controlling relay node handover, which may include:

a target base station receives a switching request message, wherein the switching request message contains an RN switching mode indication; if the target base station and/or the target cell support the RN switching mode, the target base station switches the RN according to the RN switching mode, otherwise, the RN can be switched according to the UE switching mode or the RN can be rejected for switching.

Referring to fig. 3, another method of controlling a relay node handover may include:

301. the target base station receives the switching request message;

the RN handover request message may include an RN handover mode indication, for example, indicating that the RN is ready to perform a handover in an RN handover mode.

In practical applications, the target base station may receive an X2 handover request message sent by the source base station, for example, the X2 handover request message may include an RN handover mode indication; alternatively, the target base station may receive an S1 handover request message sent by the mobility management network element, where the S1 handover request message may include an RN handover mode indication. At this time, the source base station may, for example, default that the target base station and/or the target cell support RN handover, so that the source base station may request RN handover in the RN handover mode.

302. If the target base station and/or the target cell support RN switching, the target base station switches the RN according to the RN switching mode, otherwise, the target base station switches the RN according to the UE switching mode or rejects the switching of the RN.

As can be seen from the above, after the target base station receives the handover request message including the RN handover mode indication, if the target base station and/or the target cell supports the RN handover mode, the target base station switches the RN according to the RN handover mode, otherwise, the RN may be switched or the RN may be rejected according to the UE handover mode.

The following description is from the perspective of a relay node.

Another embodiment of the method for controlling relay node handover of the present invention may include: the method comprises the steps that a Relay Node (RN) receives a switching command which is sent by a source base station and indicates to be switched to a target base station in an RN switching mode, wherein the switching command is sent by the source base station after the target base station and/or a target cell support RN switching; the RN performs handover to the target base station in the RN handover mode.

Referring to fig. 4, another method for controlling a relay node to switch provided in the embodiment of the present invention may include:

401. the RN receives a switching command which indicates that the source base station is switched to a target base station in an RN switching mode;

the handover command is sent by the source base station after determining that the target base station and/or the target cell supports RN handover, where a specific manner for the source base station to determine whether the target base station and/or the target cell supports RN handover may refer to related descriptions in the above embodiments, and details are not repeated here.

In an actual network, the RN may perform measurement reporting periodically or aperiodically, or perform measurement reporting under the trigger of a source base station or an event trigger, and if the source base station finds that the RN meets a handover condition according to the measurement reporting, for example, the channel quality of a current cell in which the RN is located drops to a set threshold, or the channel quality of a neighboring cell of the current cell in which the RN is located is better than the set threshold of the channel quality of the current cell in which the RN is located, and the like, the source base station may select whether the RN is handed over or not and a target cell to be handed over according to information reported by the handover. The source base station may select a suitable target cell for handover according to a measurement report message (the measurement report message may include measurement results for multiple cells) reported by the RN. Particularly, if the RN only indicates one DeNB cell in the measurement report, the source base station may also perform handover directly according to the reported DeNB cell. If the target base station and/or the target cell support the RN handover, the source base station may send a handover command indicating that the RN is handed over to the target base station in the RN handover mode to the RN.

402. And the RN switches to the target base station in the RN switching mode.

In the process of switching to the target base station, the RN can be synchronized to the target base station firstly and then can be accessed to the target base station based on a random access mechanism, the RN can inform the source base station of being successfully switched to the target base station after being successfully accessed to the target base station, and a relay link between the RN and the target base station is established after the RN is switched to the target base station;

the target base station may instruct the MME to move the S1 path of the RN and the attached UEs under the RN from the source base station to the target base station.

As can be seen from the above, in this embodiment, after determining that the target base station and/or the target cell supports RN handover, the source base station instructs the RN to perform handover according to the RN handover mode. The mechanism is beneficial to ensuring the reliability of RN switching, and further can ensure the service continuity of UE attached to the RN in the Relay state in the switching process.

In order to better understand and implement the above-mentioned scheme of the embodiment of the present invention, a specific implementation manner of the source base station determining whether the target base station and/or the target cell supports RN handover in the above-mentioned embodiment is described below by taking several specific application scenarios as examples.

Referring to fig. 5, in the method for a source base station to determine whether a target base station and/or a target cell supports RN handover according to an embodiment of the present invention, the source base station may acquire type information of the target base station and/or the target cell from the target base station, so as to determine whether the target base station and/or the target cell supports RN handover according to the type information, where the method may include:

501. the source base station sends an X2 setup request message to the target base station.

The source base station may carry indication information, such as Relay Mobility Support, of whether the source base station supports RN handover in the X2 setup request message, so that the target base station may also know whether the source base station supports RN handover, and subsequently, if there is an RN request handover, the target base station may handover the RN to the source base station supporting RN handover.

In one embodiment, the format of the X2 setup request message may be, for example, as follows:

wherein, the font bold part in the format is the extension content,

therein

And the message format indicates that the base station supports the RN switching mode and indicates that the base station does not support the RN switching mode, and the like.

502. The source base station receives the X2 setup response message sent by the target base station.

The target base station may carry type information of the target base station and/or the target cell in the X2 setup response message, where the type information may include indication information of whether the target base station and/or the target cell supports RN handover.

In one embodiment, the format of the X2 setup response message may be, for example, as follows:

wherein, the font bold part in the request format is the extension content,

wherein in the above-mentioned format

That is, the message format indicating that the base station supports the relay station handover mode and the message format indicating that the base station does not support the RN handover mode may be analogized.

After receiving the X2 establishment response message sent by the target base station, the source base station may analyze the X2 establishment response message, and further learn whether the target base station and/or the target cell support RN handover according to the type information carried therein.

The above solution of this embodiment mainly extends a dedicated IE in the X2 setup request message and the X2 setup response message to indicate the RN handover capability of the base station. In addition, the RN handover capability of the base station may also be indicated by an implicit indication manner, for example, a special eNB ID and an ECGI value may be defined, or other IEs capable of characterizing whether the target base station is a DeNB identity are used to indirectly indicate whether the target base station and/or the target cell supports the RN handover, for example, if the base station is a DeNB, it indicates that the base station supports the RN handover, and if the base station is a normal eNB, it indicates that the base station does not support the RN handover.

After the above-mentioned X2 service flow interaction, the source base station knows whether the target base station and/or the target cell supports RN handover, and the subsequent source base station can select a suitable target cell for the RN according to the measurement report reported by the RN, so as to satisfy the service continuity of the UE attached to the RN as much as possible. For example, if the target base station and/or the target cell supports RN handover, the source base station may perform a handover to the RN according to the RN handover pattern. In addition, if the target base station and/or the target cell do not support the RN handover, the source base station may perform the RN handover according to the UE handover mode, or the source base station may not perform the RN handover to the target base station or the target cell, and may select its target cell supporting the RN handover to perform the handover.

In the embodiment of the present invention, the base station with the relay function may further turn on or turn off the function of supporting the RN handover, for example, according to actual needs or based on configuration and requirements of an operator, that is, a certain base station may support the RN handover in some periods, and may not support the RN handover in other periods. The DeNB may inform, for example, a neighbor base station having an X2 interface with the DeNB through an X2enb configuration Update procedure, where the DeNB has turned on or off a function of supporting RN handover of the DeNB, so that the neighbor base station can process handover of the relay station according to the information. Alternatively, the DeNB may inform, for example, through an X2eNB configuration update procedure, a neighbor base station having an X2 interface with the DeNB whether the DeNB currently supports RN handover. For example, the target base station may send a base station configuration update message to the source base station, where the base station configuration update message carries type information of the target base station and/or the target cell, where the type information may include indication information of whether the target base station and/or the target cell support RN handover; after receiving the base station configuration update message from the target base station, the source base station learns whether the target base station and/or the target cell supports the RN handover according to the base station configuration update message, and the source base station may send a base station configuration update confirmation message to the target base station, where the base station configuration update confirmation message may also carry type information of the source base station, where the type information may include indication information whether the source base station supports the RN handover, and the target base station may also learn whether the source base station supports the RN handover according to the type information.

As can be seen from the above, the source base station and the target base station of this embodiment interact whether they support RN handover through the X2 service flow; if the target base station and/or the target cell are determined to support RN switching, the source base station switches the RN according to the RN switching mode subsequently, the mechanism is favorable for ensuring the reliability of RN switching, and further the service continuity of UE attached to the RN in the Relay state in the switching process can be ensured.

Referring to fig. 6, another method for a source base station to determine whether a target base station and/or a target cell support RN handover according to an embodiment of the present invention, in the method, the source base station may acquire a neighbor relation list from an OAM system to determine whether the target base station and/or the target cell support RN handover according to the neighbor relation list, where the method may include:

601. and the source base station acquires the neighbor relation list from the network OAM system.

Since the network OAM system stores the deployment information of other base stations in the area where the active base station is located, the source base station can also obtain the type information of the neighboring base stations and/or neighboring cells from the network OAM system. The DeNB may acquire the neighbor relation list NRT from the network OAM system.

The neighbor relation list maintained by each cell defines the allowable operation between the cell and a certain neighboring cell, and for example, the following attributes may be added to the neighbor relation list:

No RN HO：If checked，the Neighbor cell Relation shall not be used bythe eNB for RN handover reasons。

wherein, the attribute of No RN HO in the neighbor relation table indicates that the target base station/target cell supports RN handover; if the target base station/target cell does not support RN handover, the neighbor relation table may not carry the No RN HO attribute, and the source base station defaults to indicate that the target base station/target cell does not support RN handover.

602. And the source base station acquires the attribute information from the neighbor relation list.

If the source base station can acquire No RN HO attribute information from the neighbor relation list, the attribute information comprises indication information indicating that the target base station/target cell supports RN handover, and the source base station can acquire that the target base station/target cell supports RN handover according to the attribute information, and if the source base station does not acquire No RN HO attribute information from the neighbor relation list or acquires other attribute information indicating that the target base station/target cell does not support RN handover, the source base station can determine that the target base station/target cell does not support RN handover according to the attribute information.

The source base station acquires whether the target base station and/or the target cell supports RN handover or not through interaction with a network OAM system, and the subsequent source base station can select a relatively suitable target cell for the RN according to a measurement report reported by the RN so as to meet the service continuity of the UE attached to the RN as much as possible. For example, if the target base station and/or the target cell supports RN handover, the source base station may perform a handover to the RN according to the RN handover pattern. In addition, if the target base station and/or the target cell do not support the RN handover, the source base station may handover the RN according to the UE handover mode, or the source base station may not handover the RN to the target base station or the target cell, and may select its target cell supporting the RN handover to perform the handover.

It can be seen from the above that, in this embodiment, the source base station determines whether the target base station and/or the target cell supports RN handover by interacting with the network OAM system, and if so, the source base station switches the RN according to the RN handover mode.

Referring to fig. 7, another method for a source base station to determine whether a target base station and/or a target cell supports RN handover according to an embodiment of the present invention is provided, in which the source base station may acquire type information of the target base station and/or the target cell from a RN, so as to determine whether the target base station and/or the target cell supports RN handover according to the type information, and the method may include:

701. a source base station receives a measurement report message sent by an RN;

in an actual application scenario, the RN may acquire distribution information of all accessible denbs around from a network OAM system, and the RN may notify a source base station, which of a plurality of target base stations is a DeNB and which is an eNB, where the DeNB may generally support RN handover and the eNB does not support RN handover.

The Measurement Report Message (Measurement Report Message) carries a Measurement result of a target base station (DeNB or eNB) and type information of the target base station and/or the target cell, where the type information includes indication information for indicating whether the target base station and/or the target cell supports RN handover.

The type information of the target base station and/or the target cell may be indicated by a dedicated information element (explicit indication), or may be indirectly indicated by the type information of the target base station and/or the target cell (implicit indication) while indicating other information.

In addition, in addition to reporting the measurement report, the RN may notify the source base station of the type information of the target base station and/or the target cell through dedicated signaling, which may be, for example, an RRC message, an S1 message, or an X2 message.

In one embodiment, the format of the Measurement Report message reported by the RN may be as follows:

examples of the "MeasResults" information element in the message format may be as follows:

wherein, the above

The font bold part in the cell is the extension content;

wherein,

indicating that the target Cell is a DeNB Cell, which is equivalent to indicating that the target base station and/or the target Cell supports RN handover, and indicating that the target base station and/or the target Cell does not support the measurement report message format of the RN handover mode, and so on.

It should be noted that, the manner of carrying the type information of the target base station and/or the target cell in the measurement report message is only an example, as long as the source base station can distinguish the target cell as a denbc cell or a common eNB cell through the measurement report, or distinguish the target base station as a DeNB or a common eNB, and the method is not particularly limited herein.

702. The source base station determines whether the target base station and/or the target cell supports RN handover.

If the source base station determines that the target base station is a DeNB and/or the target cell is a DeNB cell according to the type information of the target base station and/or the target cell carried in the measurement report message, the source base station may determine that the target base station and/or the target cell supports RN handover accordingly, and otherwise, the source base station may determine that the target base station and/or the target cell does not support RN handover.

If the target base station and/or the target cell support RN switching, the source base station can select the target cell with relatively good channel quality indicated by the measurement report reported by the RN, and the RN is switched according to an RN switching mode; if the target base station and/or the target cell do not support the RN handover, the source base station may perform the handover or temporarily not perform the handover to the RN according to the UE handover mode, or the source base station may select another target cell indicated by the measurement report reported by the RN and having relatively good channel quality, and perform the handover to the RN according to the RN handover mode or the UE handover mode.

It can be understood that the above-mentioned procedure of this embodiment is mainly to notify the source base station whether the target base station and/or the target cell supports RN handover by the RN using the measurement report message. Of course, the RN may also inform the source base station whether the target base station and/or the target cell supports RN handover in various ways. For example, the RN may send a Radio Resource Control (RRC) message to the source base station, where the RRC message carries indication information for indicating whether the target base station and/or the target cell support RN handover; or, the RN may send an S1 message to the source base station, where the S1 message carries indication information for indicating whether the target base station and/or the target cell support RN handover; or, the RN may send an X2 message to the source base station, where the X2 message may carry indication information for indicating whether the target base station and/or the target cell support RN handover. Of course, the RN may also notify the source base station whether the target base station and/or the target cell supports the RN handover in other manners. The source base station can know whether the target base station and/or the target cell support the RN handover according to the information.

As can be seen from the above, the RN of this embodiment determines whether the target base station and/or the target cell supports the RN handover; and informing the source base station whether the target base station and/or the target cell support the RN switching or not, so that the source base station can know whether the target base station and/or the target cell support the RN switching or not, and if the target base station and/or the target cell support the RN switching, the source base station can switch the RN subsequently according to the RN switching mode. The mechanism is beneficial to ensuring the reliability of RN switching, and further can ensure the service continuity of UE attached to the RN in the Relay state in the switching process.

Referring to fig. 8, in the method for determining whether a target base station and/or a target cell supports RN handover by a source base station according to an embodiment of the present invention, the source base station may obtain type information of the target base station and/or the target cell from an MME, so as to determine whether the target base station and/or the target cell supports RN handover according to the type information, where the method may include:

801. the source base station sends S1 switching request information to the MME;

the S1 handover request message may include a RN HO mode indicator (RN HO indicator) indicating that the RN is ready to perform a handover in the RN mode.

The RN handover mode indication may be carried by a dedicated IE (explicit indication) or may be indicated by means of an implicit indication.

802. The MME sends S1 switching request information to the target base station;

the S1 handover request message includes a RN HO mode indicator (RN HO indicator) indicating that the RN is ready to perform a handover in the RN handover mode.

803. The target base station transmits an S1 handover Request response (S1 HO Request ACK) message to the MME;

if the target base station is a DeNB, the target base station may recognize the RN HO indicator and other information that may be carried in the S1 handover Request message, and may feed back an S1 HO Request ACK message to the MME, where the S1 HO Request ACK message may carry an acknowledgement indication corresponding to the RN HO indicator (the source base station may also know that the target base station is a DeNB and supports RN handover), and of course, the S1 HO Request ACK message may also carry other information or indication required for RN handover. If the target base station is a normal eNB, the target base station may ignore the RN HO indicator carried in the S1 handover Request message, default that the RN is a UE, and feedback an S1 HO Request ACK message (the format and content of the HO Request ACK message may be the same as those of the S1 HO Request ACK message corresponding to the UE) to the MME, where the S1 HO Request ACK message does not include an acknowledgement indication of the corresponding RN HO indicator (from which the source base station may also know that the target base station is an eNB, which does not support RN handover).

804. The MME sends an S1 handover Command (S1 HO Command) message to the source base station;

if the S1 HO Request ACK message carries the acknowledgement indication of the corresponding RN HO indicator, the MME may identify the acknowledgement indication of the corresponding RN HO indicator, and may carry the acknowledgement indication of the corresponding RN HO indicator in an S1 HO Command message sent to the source base station, of course, the S1 HO Command message may also carry other information or indication required for RN handover. The source base station can also know that the target base station is the DeNB which supports the RN switching, and the source base station can execute the subsequent RN switching operation according to the RN switching mode.

The acknowledgement indication of the corresponding RN HO indicator may be carried by a dedicated IE (explicit indication), or may also be indicated by an implicit indication manner.

In addition, if the S1 HO Request ACK message does not carry the acknowledgement indication of the corresponding RN HO indicator, the MME may identify that the target base station is the normal eNB accordingly, and the S1 HO Command message sent by the MME to the source base station does not carry the acknowledgement indication of the corresponding RN HO indicator, and of course, the S1 HO Command message may also carry other information or indication required for RN handover. The source base station can also know that the target base station is a common eNB and does not support RN switching, and the source base station can execute subsequent RN switching operation according to the UE switching mode.

As can be seen from the above, in the handover process of S1, the source base station of this embodiment first determines, by the MME, whether the target base station and/or the target cell support the relay node RN handover; if the target base station and/or the target cell are determined to support RN switching, the source base station performs subsequent switching on the RN according to the RN switching mode, the mechanism is favorable for ensuring the reliability of RN switching, and further the service continuity of UE attached to the RN in the Relay state in the switching process can be ensured.

Referring to fig. 9, another method for a source base station to determine whether a target base station and/or a target cell supports RN handover according to an embodiment of the present invention is provided, in which the source base station may obtain type information of the target base station and/or the target cell from the target base station, so as to determine whether the target base station and/or the target cell supports RN handover according to the type information, and the method may include:

901. the source base station initiates an X2 handover request message to the target base station.

The RN handover mode indication may be carried by a dedicated IE (explicit indication) or may be indicated by an implicit indication.

902. The target base station sends an X2 handover request response message (X2 HO RequestACK) to the source base station;

if the target base station is a DeNB, the target base station may recognize the RN HO indicator and other information that may be carried in the X2 handover Request message, and may feed back an X2 HO Request ACK message to the source base station, where the X2 HO Request ACK message may carry an acknowledgement indication corresponding to the RN HO indicator (the source base station may also know that the target base station is a DeNB and supports RN handover), and of course, the S1 HO Request ACK message may also carry other information or indication required for RN handover. If the target base station is a normal eNB, the target base station may ignore the RN HO indicator carried in the X2 handover Request message, default that the RN is a UE, and the target base station may feed back an X2 HO Request ACK message (the format and content of the X2 HO Request ACK message may be the same as the X2 HO Request ACK message corresponding to the UE) to the source base station, where the X2 HO Request ACK message does not include an acknowledgement indication of the corresponding RN HO indicator (the source base station may also know that the target base station is an eNB according to this, and does not support RN handover).

The acknowledgement indication of the corresponding RN HO indicator may be carried by a dedicated IE (display indication), or may also be indicated by an implicit indication manner.

The source base station receives the X2 handover response message sent by the target base station.

If the X2 HO Request ACK message carries a confirmation indication corresponding to the RN HO indicator, the source base station may also know that the target base station is a DeNB based on this, which supports RN handover, the source base station may perform a subsequent RN handover operation according to the RN handover mode, and the target base station may also perform the RN handover with the source base station according to the RN handover mode.

In addition, if the X2 HO Request ACK message does not carry the acknowledgement indication of the corresponding RN HO indicator. The source base station can also know that the target base station is a common eNB and does not support RN switching, the source base station can execute subsequent RN switching operation according to the UE switching mode, and the target base station can also perform RN switching according to the UE switching mode and the source base station and take the RN as UE for switching. Alternatively, the source base station may not perform handover temporarily, or the source base station may choose to handover the RN to another target cell supporting the RN handover.

As can be seen from the above, in the process of the X2 handover, the source base station of this embodiment first determines, through the target base station, whether the target base station and/or the target cell supports the relay node RN handover; if the target base station and/or the target cell are determined to support RN switching, the source base station performs subsequent switching on the RN according to the RN switching mode, the mechanism is favorable for ensuring the reliability of RN switching, and further the service continuity of UE attached to the RN in the Relay state in the switching process can be ensured.

To facilitate a better implementation of the above-described method of an embodiment of the present invention, the following also provides a related apparatus for implementing the above-described method.

Referring to fig. 10, an embodiment of the present invention provides a base station 1000, which may include: a determination unit 1010 and a switching control unit 1020.

A determining unit 1010, configured to determine whether the target base station and/or the target cell support relay node RN handover;

a handover control unit 1020, configured to switch the RN according to the RN handover mode when the determining unit 1010 determines that the target base station and/or the target cell supports RN handover.

The determining unit 1010 may determine whether the target base station and/or the target cell supports RN handover in various ways. The determining unit 1010 may determine by displaying an indication, for example, whether the target base station and/or the target cell supports RN handover may be determined by type information of the target base station and/or the target cell. If the type information includes an RN handover capability indication indicating whether the target base station and/or the target cell supports RN handover, the determining unit 1010 may determine whether the target base station and/or the target cell supports RN handover according to the RN handover capability indication included in the acquired type information of the target base station and/or the target cell, where the RN handover capability indication may be carried by an IE, that is, a dedicated IE for carrying the RN handover capability indication is extended from the type information, and different RN handover capabilities may be indicated by different values. Alternatively, the determining unit 1010 may also determine whether the target base station and/or the target cell supports the RN handover in a default indication manner, for example, if an IE carrying the RN handover capability indication exists in the type information of the target base station and/or the target cell, it indicates that the target base station and/or the target cell supports the RN handover, and the determining unit 1010 may determine that the target base station and/or the target cell supports the RN handover accordingly; if the type information does not include the dedicated IE for carrying the RN handover capability indication, which indicates that the target base station and/or the target cell do not support the RN handover, the determining unit 1010 may determine that the target base station and/or the target cell do not support the RN handover accordingly. Alternatively, the determining unit 1010 may also determine whether the target base station and/or the target cell supports the RN handover by means of implicit indication, for example, the determining unit 1010 may indirectly indicate whether the target base station and/or the target cell supports the RN handover by using an IE carrying other information included in the type information of the target base station and/or the target cell, for example, an IE used for indicating that the type of the target base station is a DeNB or a general eNB, where if the type information includes indication information indicating that the target base station is a DeNB, the determining unit 1010 may determine that the target base station supports the RN handover accordingly, if the type information includes indication information indicating that the target base station is a general eNB, the determining unit 1010 may determine that the target base station does not support the RN handover accordingly, and so on.

In an application scenario, the determining unit 1010 may be specifically configured to obtain type information of the target base station and/or the target cell based on an X2 service flow, and determine whether the target base station and/or the target cell supports RN handover according to the type information, where the type information includes indication information used for indicating whether the target base station and/or the target cell supports RN handover.

The determining unit 1010 may include, for example:

a first sending subunit, configured to send an X2 setup request message to a target base station;

the first receiving subunit is used for receiving an X2 establishment response message sent by the target base station; wherein, the X2 setup response message contains type information of the target base station and/or the target cell;

alternatively, the determining unit 1010 may include, for example:

and the second receiving subunit is configured to receive a base station configuration update message sent by the target base station, where the base station configuration update message includes type information of the target base station and/or the target cell.

In another application scenario, the determining unit 1010 may be specifically configured to obtain a neighboring cell relation list from a network operation management system; obtaining attribute information from the neighbor relation list; determining whether the target base station and/or the target cell support the RN handover according to the attribute information, wherein the attribute information comprises indication information used for indicating whether the target base station and/or the target cell support the RN handover;

in another application scenario, the determining unit 1010 may be specifically configured to send an S1 handover request message to the MME; receiving an S1 handover command message sent by the MME, wherein the S1 handover command message includes type information of a target base station and/or a target cell; and determining whether the target base station and/or the target cell support the RN handover or not according to the type information, wherein the type information comprises indication information used for indicating whether the target base station and/or the target cell support the RN handover or not.

In another application scenario, the determining unit 1010 may be specifically configured to receive a measurement report message sent by the RN; and determining whether the target base station and/or the target cell support the RN handover according to the measurement report message, wherein the measurement report message comprises indication information used for indicating whether the target base station and/or the target cell support the RN handover.

In an application scenario, the handover control unit 1020 may be further configured to, when the determining unit 1010 determines that the target base station and/or the target cell do not support RN handover, handover the RN according to a UE handover mode, or not handover the RN to the target base station or the target cell.

It can be understood that the base station 1000 in this embodiment may be the source base station in the foregoing method embodiment, and it may be configured to implement all technical solutions in the foregoing method embodiment in a matching manner, and the functions of each functional unit may be implemented specifically according to the method in the foregoing method embodiment, and the specific implementation process may refer to the relevant description in the foregoing embodiment, which is not described herein again.

As can be seen from the above, the source base station of this embodiment first determines whether the target base station and/or the target cell supports the RN handover; if the target base station and/or the target cell support RN switching, the source base station switches the RN according to the RN switching mode, and the source base station switches the RN according to the RN switching mode when the target base station and/or the target cell support RN switching, so that the mechanism is favorable for ensuring the reliability of RN switching, and further the service continuity of UE (user equipment) attached below the RN in the Relay state in the switching process.

Referring to fig. 11, an embodiment of the present invention provides a base station 1100, which may include: a receiving unit 1110 and a handover control unit 1120.

The receiving unit 1110 is configured to receive a handover request message, where the handover request message includes a relay node RN handover mode indication;

a handover control unit 1120, configured to, when the base station 1100 supports RN handover, handover the RN according to an RN handover mode, otherwise, handover the RN according to a UE handover mode or reject the RN handover.

In practical applications, the receiving unit 1110 may receive an X2 handover request message sent by the source base station, for example, the X2 handover request message may include an RN handover mode indication; alternatively, the receiving unit 1110 may receive an S1 handover request message sent by the mobility management network element, where the S1 handover request message may include an RN handover mode indication. At this time, the source base station may, for example, default that the target base station and/or the target cell support RN handover, so that the source base station may request RN handover in the RN handover mode.

Referring to fig. 12, an embodiment of the present invention provides a relay node 1200, including: a receiving unit 1210 and a switching unit 1220.

The receiving unit 1210 is configured to receive a handover command sent by a source base station and instructing to handover to a target base station in a relay node RN handover mode, where the handover command is sent by the source base station after it is determined that the target base station and/or a target cell support RN handover;

a handover unit 1220, configured to perform handover to the target base station in the RN handover mode.

During the process of switching to the target base station, the switching unit 1220 may synchronize to the target base station first, and then may access to the target base station based on a random access mechanism, and the switching unit 1220 may notify the source base station of successful switching to the target base station after successfully accessing to the target base station, and establish a relay link between the RN and the target base station after the RN is switched to the target base station;

in an actual network, the relay node 1200 may perform measurement reporting periodically or aperiodically, or perform measurement reporting under a trigger of a source base station or an event trigger, and if the source base station finds that the relay node 1200 meets a handover condition according to the measurement reporting, for example, the channel quality of the current cell in which the relay node 1200 is located drops to a set threshold, or the channel quality of a neighboring cell of the current cell in which the relay node 1200 is located is better than the set threshold of the channel quality of the current cell in which the relay node 1200 is located, and the like, the source base station may select whether to perform handover for the relay node 1200 and a target cell for the handover according to information reported by the handover. The source base station may select a suitable target cell for handover according to the measurement report message (which may include measurement results for multiple cells) reported by the relay node 1200. Specifically, if the relay node 1200 only indicates one DeNB cell in the measurement report, the source base station may also directly perform handover according to the reported DeNB cell. If the target base station and/or the target cell support RN handover, the source base station may send a handover command indicating to handover to the target base station in the RN handover mode to the relay node 1200.

In an application scenario, the relay node 1200 may further include: a determination unit and a notification unit (not shown in the figure).

The determining unit is used for determining whether the target base station and/or the target cell support RN handover;

and the informing unit is used for informing the source base station whether the target base station and/or the target cell support the RN switching.

In an application scenario, the notification unit may include:

a first notification subunit, configured to send a measurement report message to a source base station, where the measurement report message carries indication information used to indicate whether the target base station and/or the target cell support RN handover;

or,

a second notification subunit, configured to send an RRC message to the source base station, where the RRC message carries indication information used to indicate whether the target base station and/or the target cell support RN handover;

or,

a third notification subunit, configured to send an S1 message to the source base station, where the S1 message carries indication information used for indicating whether the target base station and/or the target cell support RN handover;

or,

a fourth notification subunit, configured to send an X2 message to the source base station, where the X2 message carries indication information used to indicate whether the target base station and/or the target cell support RN handover.

It can be understood that the relay node 1200 in this embodiment may be the relay node in the above method embodiment, and it may be configured to cooperate with all technical solutions in the above method embodiment to implement the functions of the functional units in the above method embodiment specifically, and the specific implementation process may refer to the relevant description in the above embodiment, which is not described herein again.

As can be seen from the above, the RN of the present embodiment may determine whether the target base station and/or the target cell supports the RN handover; and informing the source base station whether the target base station and/or the target cell support the RN switching or not, so that the source base station can know whether the target base station and/or the target cell support the RN switching or not, and if the target base station and/or the target cell support the RN switching, the source base station can switch the RN subsequently according to the RN switching mode. The mechanism is beneficial to ensuring the reliability of RN switching, and further can ensure the service continuity of UE attached to the RN in the Relay state in the switching process.

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

base station 1000, base station 1100, or relay node 1200.

the source base station is used for determining whether the target base station and/or the target cell support the RN handover; and if the target base station and/or the target cell support RN switching, the source base station switches the RN according to the RN switching mode.

The relay node is used for receiving a switching command which is sent by the source base station and indicates to be switched to a target base station in an RN switching mode, wherein the switching command is sent by the source base station after the target base station and/or a target cell support RN switching; and switching to the target base station in the RN switching mode.

It can be understood that the source base station and the relay node in this embodiment may be the source base station and the relay node in the foregoing method embodiment, and they may be configured to implement all technical solutions in the foregoing method embodiment in a coordinated manner, and the functions of each functional unit may be implemented specifically according to the method in the foregoing method embodiment, and the specific implementation process may refer to the relevant description in the foregoing embodiment, and is not described herein again.

It should be noted that, for simplicity of description, the above-mentioned method embodiments are described as a series of acts or combination of acts, but those skilled in the art will recognize that the present invention is not limited by the order of acts, as some steps may occur in other orders or concurrently in accordance with the invention. Further, those skilled in the art should also appreciate that the embodiments described in the specification are preferred embodiments and that the acts and elements referred to are not necessarily required to practice the invention.

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

In summary, the source base station in the embodiment of the present invention first determines whether the target base station and/or the target cell supports the RN handover; if the target base station and/or the target cell support the RN switching, the source base station switches the RN according to the RN switching mode, and the source base station switches the RN according to the RN switching mode when the target base station and/or the target cell support the RN switching, so that the mechanism is favorable for ensuring the reliability of the RN switching, and further can ensure the service continuity of UE (user equipment) attached under the RN in the Relay state in the switching process as much as possible.

It will be understood by those skilled in the art that all or part of the steps in the method for implementing the above embodiments may be implemented by hardware that is related to instructions of a program, and the program may be stored in a computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, a magnetic disk or an optical disk, etc.

The method, the related device and the communication system for controlling the relay node handover provided by the present invention are described in detail above, and a person having ordinary skill in the art may change the specific implementation manner and the application scope according to the embodiments of the present invention.

Claims

1. A method for controlling relay node handover, comprising:

2. The method of claim 1,

the determining whether the target base station and/or the target cell support the RN handover includes:

acquiring type information of a target base station and/or a target cell based on an X2 service flow;

determining whether the target base station and/or the target cell support RN switching or not according to the type information;

wherein the type information comprises indication information for indicating whether the target base station and/or the target cell support RN handover.

3. The method of claim 2,

the acquiring of the type information of the target base station and/or the target cell based on the X2 service flow includes:

sending an X2 establishment request message to a target base station; receiving an X2 establishment response message sent by the target base station; wherein, the X2 setup response message contains type information of the target base station and/or the target cell;

or,

receiving a base station configuration update message sent by a target base station, wherein the base station configuration update message comprises type information of the target base station and/or a target cell.

4. The method of claim 3,

the X2 establishment request further includes type information of the source cell and/or the source base station, and the type information of the source base station and/or the source cell includes indication information for indicating whether the source base station and/or the source cell supports RN handover.

5. The method of claim 1,

the slave network operation management system acquires a neighbor relation list;

acquiring attribute information from the neighbor relation list;

determining whether the target base station and/or the target cell support RN switching or not according to the attribute information;

wherein the attribute information includes indication information for indicating whether the target base station and/or the target cell support RN handover.

6. The method of claim 1,

sending S1 a handover request message to a mobility management entity MME;

receiving an S1 handover command message sent by the MME, wherein the S1 handover command message contains type information of a target base station and/or a target cell;

wherein the type information includes indication information for indicating whether the target base station and/or the target cell supports the RN handover.

7. The method of claim 1,

a source base station receives a measurement report message sent by an RN;

determining whether the target base station and/or the target cell support RN switching or not according to the measurement report message;

wherein the measurement report message includes indication information for indicating whether the target base station and/or the target cell supports RN handover.

8. The method according to any one of claims 1 to 7,

and if the target base station and/or the target cell do not support RN switching, the source base station switches the RN according to the UE switching mode of the user equipment, or the source base station does not switch the RN to the target base station or the target cell.

9. A method for controlling relay node handover, comprising:

and the RN switches to the target base station in an RN switching mode.

10. The method of claim 9,

before the relay node RN receives a handover command which is sent by a source base station and indicates to be handed over to a target base station in an RN handover mode, the method further includes:

the RN determines whether the target base station and/or the target cell support RN switching;

and the RN informs the source base station whether the target base station and/or the target cell support RN switching.

11. The method of claim 10,

the informing the source base station whether the target base station and/or the target cell support the RN handover includes:

sending a measurement report message to a source base station, wherein the measurement report message carries indication information for indicating whether the target base station and/or the target cell support RN handover;

or,

sending a Radio Resource Control (RRC) message to a source base station, wherein the RRC message carries indication information for indicating whether the target base station and/or the target cell support RN switching;

or,

sending an S1 message to a source base station, wherein the S1 message carries indication information for indicating whether the target base station and/or the target cell support RN handover;

or,

and sending an X2 message to the source base station, wherein the X2 message carries indication information for indicating whether the target base station and/or the target cell support RN handover.

12. A base station, comprising:

13. The base station of claim 12,

the determining unit is specifically configured to acquire type information of a target base station and/or a target cell based on an X2 service flow, and determine whether the target base station and/or the target cell supports RN handover according to the type information, where the type information includes indication information used for indicating whether the target base station and/or the target cell supports RN handover;

or,

the determining unit is used for acquiring a neighbor relation list from a network operation management system; acquiring attribute information from the neighbor relation list; determining whether a target base station and/or a target cell supports RN handover according to the attribute information, wherein the attribute information comprises indication information used for indicating whether the target base station and/or the target cell supports RN handover;

or,

the determining unit is specifically configured to send an S1 handover request message to a mobility management entity MME; receiving an S1 handover command message sent by the MME, wherein the S1 handover command message contains type information of a target base station and/or a target cell; determining whether the target base station and/or the target cell support the RN handover or not according to the type information, wherein the type information comprises indication information used for indicating whether the target base station and/or the target cell support the RN handover or not;

or,

the determining unit is specifically configured to receive a measurement report message sent by the RN; and determining whether the target base station and/or the target cell support the RN handover according to the measurement report message, wherein the measurement report message comprises indication information used for indicating whether the target base station and/or the target cell support the RN handover.

14. A relay node, comprising:

15. The relay node of claim 14,

the relay node further comprises:

a determining unit, configured to determine whether the target base station and/or the target cell supports RN handover;

16. The relay node of claim 15,

the notification unit includes:

or,

a second notification subunit, configured to send a radio resource control RRC message to the source base station, where the RRC message carries indication information used to indicate whether the target base station and/or the target cell support RN handover;

or,

17. A communication system, comprising:

the base station of any of claims 12 to 13, or the relay node of any of claims 14 to 16.