CN106211188A

CN106211188A - Method and system for replacing relay node, D2D user equipment and control node

Info

Publication number: CN106211188A
Application number: CN201510249223.6A
Authority: CN
Inventors: 黄莹; 陈琳; 谢峰
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2015-04-10
Filing date: 2015-05-15
Publication date: 2016-12-07

Abstract

The invention discloses a kind of method changing via node, including: a D2D UE receives and controls the D2D via node replacing instruction information that node sends；A described D2D UE changes instruction information according to described D2D via node, is communicated by new D2D via node.The present invention also discloses the another kind of replacing method and system of via node, D2D UE and control node.

Description

Method and system for replacing relay node, D2D user equipment and control node

Technical Field

The present invention relates to the technical field of Device-to-Device (D2D), and in particular, to a method and a system for replacing a relay node, a D2D User Equipment (UE), and a control node.

Background

With the development of wireless multimedia services, the demand for high data rate and user experience is increasing, and thus higher requirements are placed on the system capacity and coverage of the conventional cellular network. The popularity of social networking, close-range data sharing, local advertising, and like applications, on the other hand, has increased the need for people to know and communicate with people or things of interest nearby, which may be referred to as Proximity Services (Proximity Services). Against the background of the need for conventional cell-based cellular networks with significant limitations in terms of high data rates and support for proximity services, D2D technology, representing a new direction for future communication technology development, has emerged. The application of D2D technology can reduce the burden on the cellular network, reduce the battery power consumption of the user equipment, increase the data rate, and improve the robustness of the network infrastructure, well meeting the above requirements for high data rate services and proximity services.

The D2D technology may operate in licensed or unlicensed bands, allowing multiple D2D capable User Equipment (i.e., D2D User Equipment (D2D UE, D2D User Equipment)) to perform direct discovery/direct communication with or without network infrastructure. The application scenarios of D2D are mainly the following three:

1) as shown in mode 1 of fig. 1, UE1 and UE2 interact with data under the coverage of a cellular network, with user plane data not passing through the network infrastructure;

2) as shown in mode 2 of fig. 1, relaying transmissions by UEs in weak/no coverage areas allows the UE4 with poor signal quality to communicate with the network through the UE3 with nearby network coverage, which can help operators to extend coverage and increase capacity;

3) in the case of the cellular network not operating normally in the event of an earthquake or an emergency, the mode 3 shown in fig. 1 allows direct communication between devices, and the control plane and the user plane among the UE5, the UE6 and the UE7 can perform one-hop or multi-hop data communication without passing through the network infrastructure.

D2D technology generally includes D2D discovery technology and D2D communication technology; the D2D discovery technology refers to a technology for determining/determining that two or more D2D UEs are in proximity to each other (e.g., within a range where D2D direct communication is possible) or that a first user equipment is in proximity to a second user equipment. The D2D communication technology refers to a technology in which some or all of communication data between D2D UEs may be communicated directly without passing through a network infrastructure.

In the scenario corresponding to mode 2 and mode 3 shown in fig. 1, the D2D UE may act as a relay node, so that a remote D2D UE at the edge of or outside the coverage of the cellular network can perform cellular communication with the network through the relay node UE, and so that D2D UEs perform D2D communication through the relay node UE.

In the process of implementing the invention, the inventor finds that the existing D2D technology has at least the following defects:

if the status of the D2D UE or the D2D UE as the relay node changes, such as the D2D UE or the D2D UE as the relay node moves, the D2D UE needs to be changed to the serving relay node UE. The prior art does not provide a method for replacing the relay node UE in the D2D communication relay transmission mode, so that D2D communication between D2D UEs passing through the relay node UE cannot be performed smoothly.

Disclosure of Invention

In order to solve the existing technical problem, embodiments of the present invention provide a method and a system for replacing a relay node, a D2D UE, and a control node.

In order to achieve the above purpose, the technical solution of the embodiment of the present invention is realized as follows:

the embodiment of the invention provides a method for replacing a relay node, which comprises the following steps:

the first D2D UE receives D2D relay node replacement indication information sent by the control node;

the first D2D UE communicates through a new D2D relay node according to the D2D relay node replacement indication information.

In the foregoing solution, the performing communication through the new D2D relay node includes:

the first D2D UE accessing a cellular network for cellular communication through the new D2D relay node;

alternatively, the first D2D UE is in D2D communication with the second D2D UE through the new D2D relay node; the second D2D UE is a target D2D UE of the first D2D UE.

In the above scheme, before the first D2D UE performs D2D communication with the second D2DUE through the new D2D relay node, the method further includes:

the first D2D UE sending D2D relay node update information to the second D2D UE through the new D2D relay node; the D2D relay node update information is used for the second D2D UE to update self-maintained relay node information.

In the foregoing solution, the D2D relay node update information includes at least one of: identification information of the first D2D UE, identification information of the second D2D UE, identification information of the new D2D relay node, configuration information of D2D communication between the second D2D UE and the new D2D relay node.

In the foregoing solution, before receiving the D2D relay node replacement indication information sent by the control node, the method further includes:

the first D2D UE transmitting D2D relay node-related information to the control node; the D2D relay node related information is used by the control node to determine the new D2D relay node.

In the foregoing solution, the D2D relay node related information may include at least one of:

D2D relay node information detected by the first D2D UE, measurement result information of the first D2D UE on the received D2D relay node discovery message, geographical location information of the first D2D UE, identification information of the first D2D UE, communication service QoS requirement information of the first D2D UE, D2D security capability information of the first D2D UE, D2D security related parameter information of the first D2D UE, D2D communication group identification information of the first D2D UE, D2D relay type requested by the first D2D UE, identification information of the target D2D UE of the first D2D UE, priority information of the first D2D UE, priority information of the D2D communication group where the first D2D UE is located, and priority information of the communication service priority information of the first D2D UE.

In the foregoing solution, before the sending the D2D relay node related information to the control node, the method further includes:

the first D2D UE receiving configuration information related to discovery or measurement of a D2D relay node sent by the control node;

accordingly, the first D2D UE determines the D2D relay node related information according to configuration information.

In the foregoing solution, the configuration information related to discovery or measurement of the D2D relay node includes:

D2D used by the D2D relay node discovers time and/or frequency domain resources/resource pool information, identification information of the D2D relay node.

the first D2D UE receiving a D2D relay node discovery trigger threshold value sent by the control node; the D2D relay node discovery trigger threshold is a measurement threshold of the first D2D UE for the accessed original D2D relay node;

when the measurement value of the first D2D UE on the original D2D relay node is less than the D2D relay node discovery trigger threshold value, the first D2D UE turns on D2D relay node discovery.

In the foregoing scheme, after receiving the D2D relay node replacement indication information, the method further includes:

the first D2D UE replies to the control node with a D2D relay node change confirm message.

In the above scheme, the method further comprises:

the first D2D UE receives a D2D relay node update confirmation message replied by the second D2D UE through the new D2D relay node.

In the foregoing solution, the D2D relay node update confirmation information includes: identification information of the first D2D UE, identification information of the second D2D UE, identification information of the new D2D relay node.

In the foregoing solution, the D2D relay node replacement indication information includes at least one of: identification information of the first D2D UE, new D2D relay node identification information, identification information of the second D2D UE, configuration information of D2D communication between the D2D UE and a D2D relay node, a relay status indication, a relay suspension indication, a relay connection release indication, an IP address allocated by the new D2D relay node for the first D2D UE; wherein the second D2D UE is a target D2D UE of the first D2D UE.

The embodiment of the invention also provides a method for replacing the relay node, which comprises the following steps:

the control node transmits D2D relay node replacement indication information to the first D2D UE to enable the first D2D UE to communicate through a new D2D relay node according to the D2D relay node replacement indication information.

In the foregoing solution, the control node is a base station, a D2D relay node, a proximity service function entity (ProSe function), a proximity service (ProSe) application server, or a network element that performs management of a D2D relay node.

In the foregoing solution, the D2D relay node replacement indication information includes at least one of: identification information of the first D2D UE, new D2D relay node identification information, identification information of the second D2D UE, configuration information of D2D communication between the D2D UE and a D2D relay node, a relay status indication, a relay suspension indication, a relay connection release indication; wherein the second D2D UE is a target D2D UE of the first D2D UE.

In the foregoing solution, before the sending the D2D relay node replacement indication information to the first D2D UE, the method further includes:

the control node determines the new D2D relay node according to the acquired related information of the D2D relay node;

and/or, the control node determining that the first D2D UE is capable of relaying D2D communications through the new D2D relay node.

In the foregoing solution, before determining the new D2D relay node, the method further includes:

the control node receives the D2D relay node-related information sent by the first D2D UE.

In the foregoing solution, the D2D relay node related information includes at least one of:

In the foregoing solution, before the receiving the D2D relay node related information sent by the first D2D UE, the method further includes:

transmitting discovery or measurement related configuration information of a D2D relay node to the first D2D UE; the configuration information is for the first D2D UE to determine the D2D relay node-related information.

In the foregoing solution, the control node sends configuration information related to discovery or measurement of the D2D relay node to the first D2D UE through a Uu interface system message, an RRC dedicated signaling, or a PC5 interface.

transmitting a D2D relay node discovery trigger threshold value to the first D2D UE; the D2D relay node discovery trigger threshold is a measurement threshold of the first D2D UE for the accessed original D2D relay node; the D2D relay node discovery trigger threshold value is for the first D2D UE to turn on D2D relay node discovery.

In the above scheme, the determining, by the control node, that the first D2D UE can perform relay D2D communication through the new D2D relay node includes:

the control node determining, by interacting with a new D2D relay node, that the first D2D UE may relay D2D communications through the new D2D relay node; alternatively, after the control node interacts with the central control node and the new D2D relay node, it is determined that the first D2D UE may perform relay D2D communication through the new D2D relay node.

In the foregoing solution, the determining that the first D2D UE can relay the D2D communication through the new D2D relay node after interacting with the new D2D relay node includes:

the control node sends a relay access request to the new D2D relay node;

the control node receives a relay access response replied by the new D2D relay node when it determines that it is allowing the first D2D UE to communicate with D2D through the relay of the new D2D relay node.

In the above scheme, the relay access response includes: the new D2D relay node allocates an IP address for the D2D UE.

In the foregoing solution, after the control node interacts with the central control node and the new D2D relay node, determining that the first D2D UE can perform relay D2D communication through the new D2D relay node includes:

the control node sends a relay access request to the central control node;

the control node receives a relay access response sent by the central control node; the relay access response sent by the central control node is the relay access response received by the central control node; the relay access response received by the central control node is the relay access response sent by the central control node and received by the new D2D relay node, and the relay access response replied to the central control node when the D2D UE is allowed to perform D2D communication through the relay of the new D2D relay node is determined.

In the above scheme, the relay access response includes: the new D2D relay node allocating an IP address for the first D2D UE.

In the foregoing solution, the relay access request includes at least one of the following:

identification information of the first D2D UE, identification or identification list information of the second D2D UE, communication service QoS requirement information of the first D2D UE, D2D security capability information, D2D security related parameter information, D2D communication group identification information of the first D2D UE, a D2D relay type requested by the first D2D UE, priority information of the first D2D UE, priority information of a D2D communication group in which the first D2D UE is located, priority information of D2D communication service of the first D2D UE, and configuration information of D2D communication between the first D2D UE and a D2D relay node; wherein the second D2D UE is a target D2D UE of the first D2D UE.

In the foregoing solution, the configuration information communicated by D2D includes: bearer configuration information for D2D communication between the first D2D UE and the D2D relay node, and security related configuration information.

In the above scheme, the D2D relay type is UE-to-UE relay, or UE-to-network relay.

In the foregoing solution, the relay access response includes at least one of:

identification information of the first D2D UE, identification information of the second D2D UE reachable through the new D2D relay node, configuration information of D2D communications between the first D2D UE and the new D2D relay node.

In the foregoing solution, after sending the D2D relay node replacement indication information, the method further includes:

receiving a D2D relay node change confirm message replied by the first D2D UE.

In the above scheme, the method further comprises:

the control node transmitting D2D relay node update information to the second D2D UE; the D2D relay node update information is used for the second D2D UE to update self-maintained relay node information; wherein the second D2D UE is a target D2D UE of the first D2D UE.

An embodiment of the present invention further provides a D2D UE, including: a receiving module and a communication module; wherein,

the receiving module is configured to receive D2D relay node replacement indication information sent by a control node;

the communication module is configured to perform communication through a new D2D relay node according to the D2D relay node replacement indication information.

In the foregoing solution, the communication module is specifically configured to: accessing a cellular network for cellular communication through the new D2D relay node;

In the foregoing solution, the communication module is further configured to send, by the new D2D relay node, D2D relay node update information to a second D2D UE before performing D2D communication with the second D2D UE through the new D2D relay node; the D2D relay node update information is used for the second D2DUE to update of relay node information maintained by itself.

In the foregoing solution, the UE further includes: a sending module, configured to send D2D relay node-related information to the control node; the D2D relay node related information is used by the control node to determine the new D2D relay node.

In the foregoing solution, the receiving module is further configured to receive configuration information related to discovery or measurement of a D2D relay node sent by a control node before sending information related to the D2D relay node to the control node;

accordingly, the sending module determines the D2D relay node related information according to configuration information.

In the above scheme, the UE further includes a discovery module; wherein,

the receiving module is further configured to receive a D2D relay node discovery trigger threshold value sent by a control node before sending D2D relay node related information to the control node; the D2D relay node discovery trigger threshold is a measurement threshold of the first D2D UE for the accessed original D2D relay node;

the discovery module is configured to turn on D2D relay node discovery by the first D2D UE when the measurement value of the original D2D relay node is smaller than the D2D relay node discovery trigger threshold value.

In the foregoing solution, the sending module is further configured to send a D2D relay node replacement confirmation message to the control node after receiving the D2D relay node replacement indication information.

In the foregoing solution, the receiving module is further configured to receive D2D relay node update confirmation information replied by the second D2D UE through the new D2D relay node.

An embodiment of the present invention further provides a control node, including: a storage unit and a transmission unit; wherein,

the storage unit is used for storing D2D relay node replacement indication information;

the transmitting unit is configured to transmit the D2D relay node replacement indication information to the first D2D UE, so that the first D2D UE communicates through a new D2D relay node according to the D2D relay node replacement indication information.

In the foregoing solution, the control node further includes: a determining unit, configured to determine the new D2D relay node according to the obtained D2D relay node-related information; and/or determine that the first D2D UE is capable of relaying D2D communications through the new D2D relay node.

In the foregoing solution, the control node further includes: a receiving unit, configured to receive the D2D relay node related information sent by the first D2D UE before determining the new D2D relay node.

In the foregoing solution, the sending unit is further configured to send configuration information related to discovery or measurement of a D2D relay node to the first D2D UE before receiving the D2D relay node related information sent by the first D2D UE; the configuration information is for the first D2D UE to determine the D2D relay node-related information.

In the foregoing solution, the sending unit is further configured to send a D2D relay node discovery trigger threshold value to the first D2D UE before receiving the D2D relay node related information sent by the first D2D UE; the D2D relay node discovery trigger threshold is a measurement threshold of the first D2D UE for the accessed original D2D relay node; the D2D relay node discovery trigger threshold value is used for the first D2 DUE-ON D2D relay node discovery.

In the foregoing solution, the receiving unit is further configured to receive a D2D relay node change confirmation message replied by the first D2D UE after sending the D2D relay node change indication information.

In the foregoing solution, the sending unit is further configured to send D2D relay node update information to the second D2D UE; the D2D relay node update information is used for the second D2D UE to update self-maintained relay node information; wherein the second D2D UE is a target D2DUE for the first D2D UE.

An embodiment of the present invention further provides a system for replacing a relay node, including: a control node, a first D2D UE, and a new D2D relay node; wherein,

the control node to transmit D2D relay node replacement indication information to the first D2D UE;

the first D2D UE, configured to receive D2D relay node replacement indication information sent by a control node; and communicating through the new D2D relay node according to the D2D relay node replacement indication information.

In the foregoing solution, the control node is further configured to determine the new D2D relay node according to the acquired D2D relay node-related information before sending the D2D relay node replacement indication information to the first D2D UE; and/or determine that the first D2D UE is capable of relaying D2D communications through the new D2D relay node.

In the foregoing solution, the control node is further configured to receive, before determining the new D2D relay node, the D2D relay node related information sent by the first D2D UE.

In the foregoing solution, the control node is further configured to send configuration information related to discovery or measurement of a D2D relay node to the first D2D UE before receiving the information related to the D2D relay node sent by the first D2D UE;

the first D2D UE, further to determine the D2D relay node related information according to the configuration information.

In the foregoing solution, the control node is further configured to send a D2D relay node discovery trigger threshold value to the first D2D UE before receiving the D2D relay node related information sent by the first D2D UE; the D2D relay node discovery trigger threshold is a measurement threshold of the first D2D UE for the accessed original D2D relay node;

the first D2D UE further configured to turn on D2D relay node discovery when a measurement value of the original D2D relay node is less than the D2D relay node discovery trigger threshold value.

In the foregoing solution, the control node is specifically configured to determine, after interacting with a new D2D relay node, that the first D2D UE can perform relay D2D communication through the new D2D relay node; or,

the system further comprises: a central control node; wherein,

the control node is specifically configured to determine, after interaction with a central control node and the new D2D relay node, that the first D2D UE may perform relay D2D communication via the new D2D relay node.

In the above scheme, the central control node is assumed by the D2D relay node, and the central control node is configured to obtain relay-related information of the D2D relay node in the vicinity of the central control node.

In the foregoing solution, the central control node is specifically configured to: the relay related information of the relay node nearby the relay node is obtained by monitoring the relay node discovery message or the broadcast information, or the corresponding relay related information is obtained from the relay node.

In the foregoing solution, the first D2D UE is further configured to reply a D2D relay node change confirmation message to the control node after receiving the D2D relay node change indication information;

correspondingly, the control node is further configured to receive the D2D relay node replacement confirmation message.

In the foregoing solution, the first D2D UE is specifically configured to: accessing a cellular network for cellular communication through the new D2D relay node; or,

the system further comprises: a second D2D UE; wherein,

the D2D UE is specifically configured to:

D2D communications with a second D2D UE through the new D2D relay node; the second D2DUE is a target D2D UE of the first D2D UE.

In the foregoing solution, the first D2D UE is further configured to send, by the new D2D relay node, D2D relay node update information to the second D2DUE before performing D2D communication with the second D2D UE through the new D2D relay node;

the second D2D UE, further configured to update the relay node information maintained by the second D2D UE according to the received D2D relay node update information.

In the above solution, the system further includes: a second D2D UE; the second D2D UE is a target D2D UE of the first D2D UE; wherein,

the control node further to transmit D2D relay node update information to the second D2D UE;

the second D2D UE, configured to update relay node information maintained by the second D2D UE according to the received D2D relay node update information;

or,

the new D2D relay node further to send D2D relay node update information to the second D2D UE;

and the second D2D UE is configured to update the relay node information maintained by the second D2D UE according to the received D2D relay node update information.

In the foregoing solution, the second D2D UE is further configured to reply with a D2D relay node update confirmation message to the new D2D relay node after receiving the D2D relay node update message.

In the above solution, the system further includes an original D2D relay node, configured to release the connection between the first D2D UE and the first D2D UE after the first D2D UE communicates through the new D2D relay node.

In the foregoing solution, the original D2D relay node is specifically configured to: releasing a connection between itself and the first D2D UE1 after a self-maintained timer expires; or after receiving the relay connection release indication information sent by the first D2D UE, releasing the connection between the first D2D UE and the D2D UE; or, the original D2D relay node releases the connection between itself and the first D2D UE after receiving the relay connection release indication information sent by the control node.

In the foregoing solution, the original D2D relay node is further configured to start or restart the timer upon receiving the D2D communication data sent by the first D2D UE or sending the D2D communication data to the first D2D UE 162.

In the foregoing solution, the relay connection release indication information at least includes one of the following:

the release indication, identification information of the first D2D UE, identification information of the second D2D UE, a release reason; wherein the second D2D UE is a target D2D UE of the first D2D UE.

In the foregoing solution, the control node is further configured to receive, before sending the relay connection release indication information to the original D2D relay node, the D2D relay node replacement confirmation information sent by the first D2D UE; or receiving the D2D UE access completion indication information sent by the new D2D relay node.

According to the method and the system for replacing the relay node, the D2D UE and the control node, the control node sends D2D relay node replacement indication information to the first D2D UE; the first D2D UE receiving D2D relay node replacement indication information sent by a control node; the first D2D UE communicates through a new D2D relay node according to the D2D relay node replacement indication information, so that the problem that the D2D UE replaces the relay node in the D2D communication relay transmission mode is solved, the D2D UE can be timely accessed to a proper relay node, and smooth D2D communication is guaranteed.

Drawings

In the drawings, which are not necessarily drawn to scale, like reference numerals may describe similar components in different views. Like reference numerals having different letter suffixes may represent different examples of similar components. The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments discussed herein.

FIG. 1 is a schematic diagram of an application mode of D2D technology;

fig. 2 is a schematic view of a scenario in which a central control node exists in a relay mode of D2D according to an embodiment of the present invention;

fig. 3 is a flowchart illustrating a method for replacing a relay node according to an embodiment of the present invention;

fig. 4 is a flowchart illustrating a method for replacing a relay node according to a second embodiment of the present invention;

fig. 5 is a flowchart illustrating a method for replacing a relay node according to a third embodiment of the present invention;

fig. 6 is a flowchart illustrating a method for replacing a relay node according to a fourth embodiment of the present invention;

fig. 7 is a flowchart illustrating a method for replacing a relay node according to an embodiment of the present invention;

fig. 8 is a flowchart illustrating a method for replacing a relay node according to a sixth embodiment of the present invention;

fig. 9 is a flowchart illustrating a method for replacing a relay node according to a seventh embodiment of the present invention;

fig. 10 is a flowchart illustrating a method for replacing a relay node according to an eighth embodiment of the present invention;

fig. 11 is a flowchart illustrating a method for replacing a relay node according to a ninth embodiment of the present invention;

fig. 12 is a flowchart illustrating a method for replacing a relay node according to a tenth embodiment of the present invention;

fig. 13 is a flowchart illustrating an eleventh method for replacing a relay node according to an embodiment of the present invention;

fig. 14 is a schematic structural diagram of a twelve D2D UE according to an embodiment of the present invention;

FIG. 15 is a diagram illustrating a twelve control node structure according to an embodiment of the present invention;

fig. 16 is a schematic diagram of a system for twelve replacing relay nodes according to an embodiment of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples.

It should be noted that: in various embodiments of the present invention, a relay node may be referred to as a relay UE (relay UE), or referred to as a D2D access point (AP, access point) (DP for short), and the relay node may provide a function of D2D communication or cellular communication data forwarding for a D2D UE. Some Relay nodes in the Relay UE may act as a central control node (may be referred to as a DP head) and perform some control management functions. Fig. 2 is a schematic diagram of a scenario in which a central control node exists in the D2D relay mode. As shown in fig. 2, the D2D relay node is called relay UE, and may also be called D2D AP, the D2D relay node may interface with the central control node through a PC5, and the D2D relay nodes may also interact with each other through a PC5 interface. The central control node may be connected to the base station over the air interface. In addition, the central control node and the D2D relay node may also be out of the coverage of the base station, and in this scenario, the D2D relay node may also be connected to a nearby D2D relay node or the central control node through a PC5 interface. The central control node can obtain the relay related information of other relay nodes near the central control node (within the coverage area), including: relay type, relay status, location information, accessed D2D UE information, and load information, etc. Specifically, the central control node may obtain the relay-related information of the relay node in the vicinity of the central control node by monitoring the relay node discovery message or the broadcast information, or the central control node may obtain the relay-related information of the corresponding relay node from the relay node through the PC5 interface.

In various embodiments of the invention: the control node transmitting D2D relay node replacement indication information to the first D2D UE; the first D2D UE receiving D2D relay node replacement indication information sent by a control node; the first D2D UE communicates through a new D2D relay node according to the D2D relay node replacement indication information.

Example one

The embodiment provides a method for replacing a relay node, which is applied to a first D2D UE side, and the method includes:

Wherein the control node may be: a base station, a D2D relay node, a ProSe function, a ProSe application server, or a network element performing D2D relay node management.

The D2D relay node replacement indication information includes at least one of: identification information of the first D2D UE, new D2D relay node identification information, identification information of the second D2D UE, configuration information of D2D communication between the D2D UE and a D2D relay node, a relay status indication, a relay suspension indication, a relay connection release indication, an IP address allocated by the new D2D relay node for the first D2D UE; wherein the second D2D UE is a target D2D UE of the first D2D UE.

The communication through the new D2D relay node specifically includes:

alternatively, the first D2D UE communicates with the second D2D UE through the new D2D relay node in D2D.

Wherein, prior to the first D2D UE communicating with the second D2D UE through the new D2D relay node in D2D, the method may further comprise:

the first D2D UE sending D2D relay node update information to the second D2D UE through the new D2D relay node; the D2D relay node update information is used for the second D2D UE to update self-maintained relay node information;

or, the control node transmits D2D relay node update information to the second D2D UE; the D2D relay node update information is used for the second D2D UE to update self-maintained relay node information;

alternatively, the new D2D relay node sends D2D relay node update information to the target D2D UE of the D2D UEs; the D2D relay node update information is used for the second D2D UE to update self-maintained relay node information.

Wherein the D2D relay node update information may include at least one of: identification information of the first D2DUE, identification information of the second D2D UE, identification information of the new D2D relay node, configuration information of D2D communication between the second D2D UE and the new D2D relay node.

In practice, after the second D2D UE receives the D2D relay node update information, it replies D2D relay node update confirmation information to the first D2D UE through the new D2D relay node. In other words, the first D2D UE receives D2D relay node update confirmation information replied by the second D2D UE through the new D2D relay node.

Wherein the D2D relay node update confirmation information may include: identification information of the first D2D UE, identification information of the second D2D UE, and identification information of the new D2D relay node.

After receiving the D2D relay node update information, the second D2D UE communicates with the first D2D UE over the relay of the new D2D relay node in D2D.

In practical application, before receiving the D2D relay node replacement indication information sent by the control node, the method may further include:

sending D2D relay node related information to the control node; the D2D relay node related information is used by the control node to determine the new D2D relay node.

Wherein the D2D relay node related information may be D2D relay node discovery results or measurement information.

The D2D relay node related information may include at least one of:

Before the sending the D2D relay node-related information to the control node, the method may further include:

receiving configuration information related to discovery or measurement of a D2D relay node sent by the control node;

accordingly, the D2D relay node related information is determined according to configuration information.

After receiving the D2D relay node replacement indication information, the method may further include:

replying to the control node a D2D relay node replacement acknowledgement message.

Wherein the configuration information related to discovery or measurement of the D2D relay node may include:

D2D used by the D2D relay node discovers time and/or frequency domain resources (or resource pool information), and D2D relay node identification information.

receiving a D2D relay node discovery trigger threshold value sent by the control node; the D2D relay node discovery trigger threshold is a measurement threshold of the first D2D UE for the accessed original D2D relay node;

the first D2D UE turns on D2D relay node discovery when the measurement of the original D2D relay node is less than the D2D relay node discovery trigger threshold value.

The embodiment also provides a method for replacing a relay node, which is applied to a control node, and the method includes:

the control node transmits D2D relay node replacement indication information to a first D2D UE to enable the first D2D UE to communicate through a new D2D relay node according to the D2D relay node replacement indication information.

Before the transmitting the D2D relay node replacement indication information to the first D2D UE, the method may further include:

Before the determining the new D2D relay node, the method may further include:

The D2D relay node related information may be a D2D relay node discovery result or measurement information, and specifically may include at least one of the following: D2D relay node information detected by the first D2D UE, measurement result information of the first D2D UE on the received discovery message of D2D relay node; the D2D relay node related information may further include at least one of: geographical location information of the first D2D UE, identification information of the first D2D UE, communication service QoS requirement information of the first D2D UE, D2D security capability information of the first D2D UE, D2D security-related parameter information of the first D2D UE, D2D communication group identification information of the first D2D UE, a D2D relay type requested by the first D2D UE, identification information of the second D2D UE, priority information of the first D2D UE, priority information of a D2D communication group where the first D2D UE is located, and priority information of a D2D communication service of the first D2D UE.

Wherein the D2D relay node information detected by the first D2D UE may be obtained from the D2D relay discovery message received by the first D2D UE.

Before the receiving the D2D relay node-related information sent by the first D2D UE, the method may further include:

In practical application, the control node may send discovery or measurement related configuration information of the D2D relay node to the first D2D UE through a Uu interface system message, or RRC dedicated signaling, or a PC5 interface.

In practical application, before the receiving the D2D relay node-related information sent by the first D2D UE, the method may further include:

The determining, by the control node, that the first D2D UE can perform relay D2D communication through the new D2D relay node may specifically include:

Wherein, the method can also comprise:

the control node transmitting D2D relay node update information to the second D2D UE; the D2D relay node update information is used for the second D2D UE to update self-maintained relay node information.

The D2D relay node update information includes at least one of: identification information of the first D2D UE, identification information of the second D2D UE, identification information of the new D2D relay node, configuration information of D2D communication between the second D2D UE and the new D2D relay node.

The D2D relay node may act as a central control node, and the central control node may obtain relay-related information of its nearby D2D relay node, for example: relay type, relay status, location information, accessed D2DUE information, and load information, etc. The central control node may obtain relay-related information of relay nodes in its vicinity by listening to the relay node discovery message or broadcast information, or the central control node may obtain its relay-related information from the relay nodes.

The determining that the first D2D UE may relay the D2D communication through the new D2D relay node after interacting with the new D2D relay node specifically includes:

the control node sends a relay access request to the new D2D relay node;

Wherein, the relay access response may include: the new D2D relay node allocates an IP address for the D2 DUE.

After the control node interacts with the central control node and the new D2D relay node, determining that the first D2D UE can perform relay D2D communication through the new D2D relay node specifically includes:

the control node sends a relay access request to the central control node;

the control node receives a relay access response sent by the central control node; the relay access response sent by the central control node is the relay access response received by the central control node; the relay access response received by the central control node is the relay access response sent by the central control node and received by the new D2D relay node, and the relay access response replied to the central control node when the first D2D UE is allowed to carry out D2D communication through the relay of the new D2D relay node is determined.

Wherein, the relay access request includes at least one of the following:

identification information of the first D2D UE, identification or identification list information of the second D2D UE, communication service QoS requirement information of the first D2D UE, D2D security capability information, D2D security related parameter information, D2D communication group identification information of the first D2D UE, a D2D relay type requested by the first D2D UE, priority information of the first D2D UE, priority information of a D2D communication group in which the first D2D UE is located, priority information of a D2D communication service of the first D2D UE, and configuration information of D2D communication between the first D2D UE and a D2D relay node.

Wherein the configuration information of the D2D communication includes: bearer configuration information, safety-related configuration information and the like of the D2D communication between the first D2D UE and the D2D relay node.

The relay access response may include: the new D2D relay node allocates an IP address for the first D2 DUE.

The relay access response includes at least one of:

identification information of the first D2D UE, identification (list) information of a target D2D UE of the D2D UE reachable through the new D2D relay node, configuration information of D2D communication between the first D2D UE and the new D2D relay node.

The D2D relay type may be classified as: UE to UE relay, UE to network relay.

After sending the D2D relay node replacement indication information, the method may further include:

receiving a D2D relay node change confirm message replied by the first D2D UE.

The present embodiment further provides a method for replacing a relay node, as shown in fig. 3, the method includes the following steps:

step 301: the control node transmitting D2D relay node replacement indication information to the first D2D UE;

here, the control node may be: a base station, a D2D relay node, a ProSe function, a ProSe application server, or a network element performing D2D relay node management.

Before the determining the new D2D relay node, the method may further include:

the control node transmitting discovery or measurement related configuration information of a D2D relay node to the first D2D UE;

the first D2D UE determining the D2D relay node-related information according to the configuration information.

the control node transmitting a D2D relay node discovery trigger threshold value to the first D2D UE; the D2D relay node discovery trigger threshold is a measurement threshold of the first D2D UE for the accessed original D2D relay node;

when the measurement of the original D2D relay node is less than the D2D relay node discovery trigger threshold value, the first D2D UE turns on D2D relay node discovery.

Among them, the D2D relay node may be used as a central control node, and the central control node may obtain relay-related information of its nearby D2D relay node, for example: relay type, relay status, location information, accessed D2D UE information, and load information, etc. The central control node may obtain relay-related information of relay nodes in its vicinity by listening to the relay node discovery message or broadcast information, or the central control node may obtain its relay-related information from the relay nodes.

the control node sends a relay access request to the new D2D relay node;

the new D2D relay node determining a relay access response to reply to the control node when itself allows the first D2D UE to conduct D2D communications through the relay of the new D2D relay node.

the control node sends a relay access request to the central control node;

the central control node sends a relay access request to a new D2D relay node;

the new D2D relay node replying a relay access response to the central control node when determining itself to allow the first D2D UE to conduct D2D communications through the relay of the new D2D relay node;

and after receiving the relay access response, the central control node replies and sends the relay access response to the control node.

Wherein, the relay access request includes at least one of the following:

The relay access response includes at least one of:

The D2D relay type may be classified as: UE to UE relay, UE to network relay.

Step 302: the first D2D UE receiving D2D relay node replacement indication information sent by a control node;

here, after receiving the D2D relay node replacement indication information, the method may further include:

Step 303: the first D2D UE communicates through a new D2D relay node according to the D2D relay node replacement indication information.

Here, the performing communication through the new D2D relay node specifically includes:

the first D2D UE accessing a cellular network for cellular communication through the new D2D relay node; or,

the first D2D UE sending D2D relay node update information to the second D2D UE through the new D2D relay node; and the second D2D UE updates the self-maintained relay node information according to the received D2D relay node updating information.

The method may further comprise:

the control node transmitting D2D relay node update information to the second D2D UE; the second D2D UE updates the self-maintained relay node information according to the received D2D relay node updating information; or,

the new D2D relay node sending D2D relay node update information to the second D2D UE; and the second D2D UE updates the self-maintained relay node information according to the received D2D relay node updating information.

The method may further comprise: the second D2D UE, after receiving the D2D relay node update information, replies a D2D relay node update confirmation information to the new D2D relay node.

Wherein the D2D relay node update confirmation information may include: identification information of the first D2D UE, identification information of the second D2D UE, identification information of the new D2D relay node.

After the first D2D UE communicates through the new D2D relay node, the method may further include:

the original D2D relay node of the first D2D UE releasing the connection between itself and the first D2D UE;

specifically, the original D2D relay node releases the connection between itself and the first D2D UE after the timeout of its own maintained timer; or, after receiving the relay connection release indication information sent by the first D2D UE, the original D2D relay node releases the connection between itself and the D2D UE; or, the original D2D relay node releases the connection between itself and the first D2D UE after receiving the relay connection release indication information sent by the control node.

Wherein the original D2D relay node starts or restarts the timer upon receiving the D2D communication data transmitted by the first D2D UE or transmitting the D2D communication data to the first D2D UE.

The relay connection release indication information includes at least one of:

the release indication, the identification information of the first D2D UE, the identification information of the second D2D UE, a release reason.

Before the control node sends relay connection release indication information to the original D2D relay node, the method may further include:

the control node receives D2D relay node replacement confirmation information sent by the first D2D UE; or,

the control node receives D2D UE access completion indication information sent by the new D2D relay node.

In the method for replacing a relay node provided by the embodiment of the invention, the control node sends D2D relay node replacement indication information to the first D2D UE; the first D2D UE receiving D2D relay node replacement indication information sent by a control node; the first D2D UE communicates through a new D2D relay node according to the D2D relay node replacement indication information, so that the problem that the D2D UE replaces the relay node in the D2D communication relay transmission mode is solved, the D2D UE can be timely accessed to a proper relay node, and smooth D2D communication is guaranteed.

Example two

The application scenario of this embodiment is as follows: D2D UE1, D2D UE2, relay UE1, and relay UE2 are all within cellular communication network coverage and are all D2D UEs; also, the relay UE1 and the relay UE2 may serve as relay nodes to provide relay services for other D2D UEs. It is noted that the D2D UE may connect to different relay UEs, and may send D2D data to different target D2DUE through different relay UEs.

In this embodiment, a method for replacing a relay node in a scenario from D2D UE to UE relay is shown in fig. 4, and includes the following steps:

step 401: D2D UE1 and D2D UE2 communicate D2D through relay UE1 as a relay node, and D2D UE1 determines that a replacement of the relay UE is required;

here, the manner in which the D2D UE1 determines that replacement of the relay UE is required may be any one of:

in the first mode, when the D2D UE1, the D2D UE2 or the relay UE1 moves, the D2D UE1 detects that the signal quality between the D2D UE1 and the relay UE1 is poor, and at this time, the D2D UE1 needs to search for a new relay node, the relay UE discovery and measurement process is executed;

second, the D2D UE1 may be triggered for relay UE replacement by the relay UE 1; for example, when the relay UE1 is low in power, the relay UE1 may send a low power, a relay suspension indication, a relay status indication, or a relay connection release indication to the D2D UE1 through D2D broadcast or unicast communication, so as to trigger the D2D UE1 to perform relay UE replacement, that is, trigger the D2DUE1 to perform a relay UE discovery and measurement procedure.

In a third mode, the base station sends a D2D relay node discovery trigger threshold value to a D2D UE 1; the D2D relay node discovery trigger threshold value is a measurement threshold value of the D2D UE1 for the accessed relay UE 1; when the measured value of relay UE1 is less than the D2D relay node discovery trigger threshold value, the D2DUE1 starts relay UE discovery.

In practical applications, in a first mode, before the D2D UE1 performs relay UE discovery and measurement procedures, the D2D UE1 may also obtain (for example, obtain through a System Information Block (SIB)) from the base station, through active transmission by the base station, the D2D discovery resource configuration Information used by the relay UE; or after determining that the relay UE discovery process needs to be executed, the D2D UE1 sends D2D relay UE discovery indication information to the base station, and after receiving the discovery indication information, the base station sends D2D discovery resource configuration information used by the relay UE to the D2D UE 1.

Here, the D2D discovery resource configuration information may include: frequency point, subframe, Physical Resource Block (PRB), and relay UE identity.

Step 402: D2D UE1 performed relay UE discovery and measurement procedures;

here, the relay UE discovery and measurement process can adopt two modes, i.e. Model a or Model B. In the Model A mode, a relay UE broadcasts a D2D discovery message; the D2D discovery message may include: identification information of the relay UE, Public Land Mobile Network (PLMN) Identification (ID) to which a radio carrier frequency used for D2D communication between the D2D UE and the relay UE belongs, connection related information (for identifying connection information that can be provided by the UE to the Network (UE-to-Network) relay UE, such as Access Point Name (APN) information, and relay status information (such as suspension of relay, insufficient power, etc.); in the Model B scheme, the D2D UE broadcasts the relay node discovery message, and the relay UE serving as the relay node receives the broadcasted relay node discovery message and then transmits a response message to the D2D UE.

In practical applications, the D2D UE1 may obtain discovery or measurement related resource configuration information used by the relay UE from the base station or from the prosecution before performing the relay UE discovery procedure. The resource configuration information may include: D2D used by the relay UE finds time domain and/or frequency domain resource information, identification information of the relay UE, and the like. The D2D UE1 may perform discovery or measurement of relay UEs according to the received resource configuration information.

Step 403: the D2D UE1 sends relay UE discovery results or measurement information to the base station;

here, the discovery result or the measurement information may include: relay node identification information (such as ProSe ID, etc.) of the D2D relay discovery message received by the D2D UE1, and measurement results (such as signal strength, etc.) of the D2D UE1 on the discovery message of the received relayaue.

In practical application, the D2D UE1 may also send its own geographical location information to the base station.

In practical application, the D2D UE1 may further send the identification information of the D2D UE1, the QoS requirement information of the communication service of the D2D UE1, the security capability information of the D2D, the security related parameter information of the D2D, the identification information of the D2D communication group of the D2D UE1, the priority information of the D2D UE1, the priority information of the D2D communication group where the D2D UE1 is located, the priority information of the D2D communication service of the D2D UE1, the requested D2D relay type, and the identification information of the target D2D UE to the base station. Wherein, the D2D relay type includes: UE-to-UE relay, and UE-to-network relay.

Step 404: the base station selects one or more relay UEs for the D2D UE1 as candidate new relay nodes according to the received relay UE discovery result or the measurement information;

for example, the base station selects relay UEs with better signal quality as candidate relay nodes from the relay UEs discovered by the UEs.

Here, it is assumed that the candidate new relay node is relay UE 2.

Step 405: the base station sends a relay access request message to the relay UE 2;

here, the relay access request message may include: identification information of D2D UE1, identification or identification list information of target D2D UE of D2D UE1 (e.g., identification of D2D UE2), communication service QoS requirement information of D2D UE, D2D security capability information, D2D security related parameter information, D2D communication group identification information of D2D UE1, D2D relay type requested by D2D UE1, priority information of D2D UE1, priority information of D2D communication group where D2D UE1 is located, priority information of D2D communication service of D2D UE1, and configuration information of D2D communication between D2D UE1 and relay UE2, etc.

The communication service QoS requirement information of the D2D UE may include: QoS Class Identifier (QCI), Allocation Reservation Priority (ARP), Guaranteed Bit Rate (GBR), GBR, and MBR.

The D2D relay types requested by the D2D UE1 may include: UE to UE relay, UE to network relay.

The configuration information for D2D communication between the D2D UE1 and the relay UE2 may include: D2D communicates bearer configuration information, security-related configuration information, and the like.

Step 406: after receiving the relay access request message, the relay UE2 needs to perform admission control to determine whether to allow the D2D UE1 to perform D2D communication with a target D2D UE (D2DUE2) of the D2D UE1 through relay of the relay UE 2;

specifically, the relay UE2 may determine whether to allow the D2D UE1 access according to its own relay capability, transceiving capability, the number of D2D UEs that have accessed, priority information, and information such as the traffic QoS requirement of the D2D UE.

Optionally, the relay UE2 may detect a D2D UE nearby itself by monitoring the D2D discovery signal, and acquire identification information thereof; accordingly, the relay UE2 may determine whether D2D communication data of the D2D UE1 can be forwarded to the D2D UE2 according to the nearby D2D UE information detected by itself.

Step 407: the relay UE2 sends a relay access response message to the base station when the relay UE2 determines that the D2D UE1 is allowed to access and the relay UE2 can forward the D2D data to the D2D UE 2;

here, the relay access response message may include: identification information of the D2D UE1, identification or identification list information of the D2D UE2 that can be routed through the relay UE2, and configuration information of the D2D communication between the D2D UE1 and the relay UE2, an IP address allocated by the relay UE2 to the D2D UE1, and the like.

The configuration information of D2D communication between the D2D UE1 and the relay UE2 may include D2D communication bearer configuration information, security-related configuration information, and the like.

If the relay UE2 determines that the D2D UE1 is not allowed access, or the relay UE2 cannot forward the D2D data to the D2D UE2, then a reject message is replied to the base station, which may select other candidate relay UEs for the D2D UE 1.

Step 408: after receiving the relay access response message, the base station sends a relay UE replacement command to the D2D UE1 to command the D2D UE1 to access the new relay UE;

here, the relay UE change command may include: identification information of the new D2D relay node (i.e., relay UE2), identification information of D2D UE1, identification or identification list information of D2D UE2 that may be routed through the new D2D relay node, configuration information of D2D communications between D2D UE1 and relay UE2, and an IP address assigned by relay UE2 for D2D UE 1.

The configuration information of D2D communication between the D2D UE1 and the relay UE2 may include: D2D communication bearer configuration information, security related configuration information, and the like.

Step 409: when the D2D UE1 confirms that D2D communication is performed with the D2D UE2 through relay of the relay UE2, transmitting a relay UE replacement confirmation to the base station;

step 410: after receiving the change confirmation of the relay UE, the base station sends a relay connection release message to the original relay UE (namely, relay UE1) of the D2D UE 1; accordingly, the relay UE1 releases the relevant context information of the relay UE1 after receiving the relay connection release message;

here, the relay connection release message may include: a release indication, identification information of the D2D UE1, identification information of a target D2D UE of the D2D UE1 (i.e., D2D UE2), and a release reason, etc.

In practical application, after receiving the relay connection release message, the relay UE1 may send a relay connection release message to the D2D UE1 to instruct the D2D UE1 to release the connection between the relay UE1 and the UE 1; alternatively, the relayaue 1 may also determine whether to release its connection with the D2D UE1 based on a self-maintained timer. Specifically, the relay UE1 starts/restarts the timer each time it receives a D2D communication packet sent by the D2D UE1, releases its connection with the D2D UE1 when the timer expires, and deletes the D2D UE1 related context.

Step 411: the D2D UE1 sends relay UE update information to the D2D UE2 through a new D2D relay node (relay UE2) for updating relay node information maintained at the target D2D UE (i.e., D2D UE 2);

wherein, the D2D relay node update information may include: identification information of the D2D UE1, identification information of a target D2D UE of the D2D UE1 (i.e., D2D UE2), identification information of a new D2D relay node (i.e., relay UE2), and configuration information of D2D communication between the relay UE2 and the D2D UE 2.

Step 412: after receiving the relay UE update information, the D2D UE2 updates the relay node information maintained by itself, and sends relay UE update confirmation information to the D2D UE1 through a new D2D relay node (relay UE 2).

Wherein the relay UE update confirmation information may include: identification information of D2D UE1, identification information of a target D2D UE of D2D UE1 (i.e., D2D UE2), and identification information of a new D2D relay node (i.e., relayUE 2).

The D2D UE2 subsequently communicates with the D2D UE1 in D2D via the relay of the new D2D relay node (i.e., relay UE 2).

It should be noted that: the method of the embodiment is also applicable to the relay scenario from the UE to the network. When the scheme of the present embodiment is used in the UE-to-network relay scenario, the message of the above step does not need to include the target D2D UE identification information of the relay UE1, and the relay UE update procedure, i.e., steps 411 and 412, does not need to be performed.

EXAMPLE III

The application scenario of this embodiment is as follows: D2D UE1, D2D UE2, relay UE1, and relay UE2 are all within cellular communication network coverage and are all D2D UEs; also, the relay UE1 and the relay UE2 may serve as relay nodes to provide relay services for other D2D UEs. Note that the D2D UE may connect to different relay UEs, sending D2D data to different target D2D UEs through the different relay UEs.

In this embodiment, a method for replacing a relay node in a scenario from D2D UE to UE relay is shown in fig. 5, and includes the following steps:

step 501: D2D UE1 and D2D UE2 communicate D2D through relay UE1 as a relay node, and D2D UE1 determines that a replacement of the relay UE is required;

second, relay UE1 may trigger a relay UE change of D2D UE1, for example, when the power of relay UE1 is insufficient, the relay UE1 may send the power shortage, or suspend the relay indication, or relay status indication, or relay connection release indication through D2D broadcast or unicast communication.

In practical applications, in the first mode, before the D2D UE1 performs relay UE discovery and measurement procedures, the D2D UE1 may also obtain (e.g., obtain through SIB) the D2D discovery resource configuration information used by the relay UE from the base station through active transmission by the base station; or after determining that relay UE discovery needs to be performed, the D2D UE1 sends D2D relay UE discovery indication information to the base station, and the base station sends D2D discovery resource configuration information used by the relay UE to the D2D UE1 after receiving the discovery indication information.

Here, the D2D discovery resource configuration information may include: frequency point, subframe, PRB, and relayUE identity.

Step 502: D2D UE1 performed relay UE discovery and measurement procedures;

here, the relay UE discovery and measurement process can adopt two modes, i.e. Model a or Model B. In the Model A mode, a relay UE broadcasts a D2D discovery message; the D2D discovery message may include: identification information of the relay UE, PLMN ID to which a radio carrier frequency used for D2D communication between the D2D UE and the relay UE belongs, connection related information (for identifying connection information, such as APN information, which can be provided by the UE-to-network relay UE), and relay state information (such as suspension of relay, insufficient power, etc.); in the Model B scheme, the D2D UE broadcasts the relay node discovery message, and relay UEs that can act as relay nodes receive the relay node discovery message and then transmit response messages to the D2D UE.

In practical applications, the D2D UE1 acquires relay node discovery or measurement related configuration information from the base station or prose before performing the relay UE discovery procedure. Wherein, the configuration information may include: D2D used by the relay UE finds time domain and/or frequency domain resource information, identification information of the relay UE, and the like. The D2D UE1 may perform discovery or measurement of relay UEs according to the received configuration information.

Step 503: the D2D UE1 sends relay UE discovery results or measurement information to the base station;

here, the discovery result or the measurement information may include: relay node identification information (such as ProSe ID, etc.) of the D2D relay discovery message received by the D2D UE1, and measurement results (such as signal strength, etc.) of the D2D UE on the discovery message of the received relay UE.

In practical application, the D2D UE1 may further send identification information of the D2D UE1, QoS requirement information of the communication service of the D2D UE, D2D security capability information, D2D security-related parameter information, D2D communication group identification information of the D2D UE1, priority information of the D2D UE1, priority information of a D2D communication group where the D2D UE1 is located, priority information of the D2D communication service of the D2D UE1, a requested D2D relay type, and identification (or identification list) information of the target D2D UE to the base station. Wherein, the D2D relay type includes: UE-to-UE relay, and UE-to-network relay.

Step 504: the base station selects one or more relay UEs for the D2D UE1 as candidate new relay nodes according to the received relay UE discovery result or the measurement information;

Here, it is assumed that the candidate new relay node is relay UE 2.

Step 505: the base station sends a relay access request message to the relay UE 2;

here, the relay access request message may include: identification information of D2D UE1, identification or identification list information of target D2D UE of D2D UE1 (e.g., identification of D2D UE2), communication service QoS requirement information of D2D UE, D2D security capability information, D2D security-related parameter information, D2D communication group identification information of D2D UE1, D2D relay type requested by D2D UE1, priority information of D2D UE1, priority information of D2D communication group where D2D UE1 is located, priority information of D2D communication service of D2D UE1, configuration information of D2D communication between D2D UE1 and relay UE2, and the like.

The communication service QoS requirement information of the D2D UE may include: QCI, ARP, whether GBR, and MBR.

The D2D relay type requested by the D2D UE may include: UE-to-UE relay, UE-to-network relay.

Step 506: after receiving the relay access request message, the relay UE2 needs to perform admission control to determine whether to allow the D2D UE1 to perform D2D communication with the D2D UE2 through the relay of the relay UE 2;

Optionally, the relay UE2 may detect a D2D UE nearby itself by listening to the D2D discovery signal and acquire its identification information; accordingly, the relay UE2 may determine whether D2D communication data of the D2D UE1 can be forwarded to the D2D UE2 according to the nearby D2D UE information detected by itself.

Step 507: the relay UE2 sends a relay access response message to the base station when the relay UE2 determines that the D2D UE1 is allowed to access and the relay UE2 can forward the D2D data to the D2D UE 2;

Step 508: after receiving the relay access response message, the base station sends a relay UE replacement command to the D2D UE1 to command the D2D UE1 to access the new relay UE;

here, the relay UE change command may include: identification information of a new D2D relay node (i.e., relay UE2), identification information of D2D UE1, identification or identification list information of D2DUE2 that can be routed through the new D2D relay node, configuration information of D2D communication between D2D UE1 and relay UE2, and an IP address allocated by the relay UE2 for the D2D UE 1.

Step 509: if the D2D UE1 confirms that D2D communication is carried out with the D2D UE2 through the relay of the relay UE2, sending a relay UE replacement confirmation to the base station;

step 510: after the D2D UE1 sends a relay UE replacement confirmation to the base station, it sends a relay connection release message to the original relay UE (i.e. relay UE1) of the D2D UE1 to release the connection between itself and the relay UE 1; accordingly, the relay UE1 releases the relevant context information of the relay UE1 after receiving the relay connection release message;

here, the relay connection release message may include: a release indication, identification information of the D2D UE1, identification information of a target D2D UE (i.e., D2D UE2) of the D2D UE1, and a release reason, etc.

In practical applications, after receiving the relay connection release message, the relay UE1 may send a relay connection release message to the D2D UE1, instructing the D2D UE1 to release its connection with the relay UE 1.

Step 511: a new D2D relay node (relay UE2) of the D2D UE1 sends relay UE update information to target D2D UEs (including at least D2D UE2) of the D2D UE1 for updating relay node information maintained at the target D2D UEs (i.e., D2D UE 2);

Step 512: after receiving the D2D relay node update information, the D2D UE2 updates the relay node information maintained by itself, and sends relay UE update confirmation information to the relay UE 2.

It should be noted that: the method of the embodiment is also applicable to the relay scenario from the UE to the network. When the scheme of the present embodiment is used in the UE-to-network relay scenario, the target D2D UE identification information of the relay UE1 need not be included in the message of the above step, and the relay UE update procedure need not be performed, i.e., steps 511 and 512 need not be performed.

Example four

In this embodiment, a method for replacing a relay node in a scenario from D2D UE to UE relay is shown in fig. 6, and includes the following steps:

step 601: D2D UE1 and D2D UE2 communicate D2D through relay UE1 as a relay node, and D2D UE1 determines that a replacement of the relay UE is required;

Step 602: D2D UE1 performed relay UE discovery and measurement procedures;

here, the relay UE discovery and measurement process can adopt two modes, i.e. Model a or Model B. In the Model A mode, a relay UE broadcasts a D2D discovery message; the D2D discovery message may include: identification information of the relay UE, PLMN ID to which a radio carrier frequency used for D2D communication between the D2D UE and the relay UE belongs, connection related information (for identifying connection information, such as APN information, which can be provided by the UE-to-network relay UE), and relay state information (such as suspension of relay, insufficient power, and the like); in the Model B scheme, the D2D UE broadcasts the relay node discovery message, and relay UEs that can act as relay nodes receive the relay node discovery message and then transmit response messages to the D2D UE.

In practical applications, the D2D UE1 acquires the relay node discovery or measurement related resource configuration information from the base station or the prose function before performing the relay UE discovery procedure. The resource configuration information may include: D2D used by the relay UE finds time domain and/or frequency domain resource information, identification information of the relay UE, and the like. The D2D UE1 may perform discovery or measurement of relay UEs according to the received resource configuration information.

Step 603: the D2D UE1 sends relay UE discovery results or measurement information to the base station;

here, the discovery result and the measurement information may include: relay node identification information (such as ProSe ID, etc.) of the D2D relay discovery message received by the D2D UE1, and measurement results (such as signal strength, etc.) of the D2D UE on the discovery message of the received relay UE.

Step 604: the base station selects one or more relay UEs for the D2D UE1 as candidate new relay nodes according to the received relay UE discovery result or the measurement information;

Here, it is assumed that the candidate new relay node is relay UE 2.

Step 605: the base station sends a relay access request message to the relay UE 2;

Step 606: after receiving the relay access request message, the relay UE2 needs to perform admission control to determine whether to allow the D2D UE1 to perform D2D communication with the D2D UE2 through the relay of the relay UE 2;

Step 607: the relay UE2 sends a relay access response message to the base station when the relay UE2 determines that the D2D UE1 is allowed to access and the relay UE2 can forward the D2D data to the D2D UE 2;

Step 608: after receiving the relay access response message, the base station sends a relay UE replacement command to the D2D UE1 to command the D2D UE1 to access the new relay UE;

Step 609: when the D2D UE1 confirms that D2D communication is performed with the D2D UE2 through relay of the relay UE2, transmitting a relay UE replacement confirmation to the base station;

step 610: after the D2D UE1 sends a relay UE replacement confirmation to the base station, it sends a relay connection release message to the original relay UE (i.e. relay UE1) of the D2D UE1 to release the connection between itself and the relay UE 1; accordingly, the relay UE1 releases the relevant context information of the relay UE1 after receiving the relay connection release message;

Step 611: after receiving the relay UE replacement confirmation of the D2D UE1, the base station sends relay UE update information to target D2D UE (including at least D2D UE2) of the D2D UE1, wherein the relay UE update information is used for updating relay node information maintained at the target D2DUE (namely D2D UE 2);

It should be noted that: this step may occur before or after step 510.

Step 612: and after receiving the relay UE update information, the D2D UE2 updates the relay node information maintained by itself and sends relay UE update confirmation information to the base station.

It should be noted that: the method of the embodiment is also applicable to the relay scenario from the UE to the network. When the scheme of the present embodiment is used in the UE-to-network relay scenario, the message of the above step does not need to include the target D2D UE identification information of the relay UE1, and the relay UE update procedure, i.e., steps 611 and 612, does not need to be performed.

EXAMPLE five

In this embodiment, a method for replacing a relay node in a scenario from D2D UE to UE relay is shown in fig. 7, and includes the following steps:

step 701: D2D UE1 and D2D UE2 communicate D2D through relay UE1 as a relay node, and D2D UE1 determines that a replacement of the relay UE is required;

Step 702: D2D UE1 performed relay UE discovery and measurement procedures;

here, the relay UE discovery and measurement process can adopt two modes, i.e. Model a or Model B. In the Model A mode, a relay UE broadcasts a D2D discovery message; the D2D discovery message may include: identification information of the relay UE, PLMN ID to which the radio carrier frequency used for D2D communication between the D2D UE and the relay UE belongs, connection related information (for identifying connection information, such as APN information, which can be provided by the UE-to-Network relay UE), and relay state information (such as suspension of relay, insufficient power, etc.); in the Model B scheme, the D2D UE broadcasts the relay node discovery message, and relay UEs that can act as relay nodes receive the relay node discovery message and then transmit response messages to the D2D UE.

Step 703: the D2D UE1 sends relay UE discovery results or measurement information to the base station;

Step 704: the base station selects one or more relay UEs for the D2D UE1 as candidate new relay nodes according to the received relay UE discovery result or the measurement information;

Here, it is assumed that the candidate new relay node is relay UE 2.

Step 705: the base station sends a relay access request message to the relay UE 2;

The D2D relay types requested by the D2D UE1 may include: UE-to-UE relay, UE-to-network relay.

Step 706: after receiving the relay access request message, the relay UE2 needs to perform admission control to determine whether to allow the D2D UE1 to perform D2D communication with the D2D UE2 through the relay of the relay UE 2;

In practice, step 606 may not be executed first, i.e. step 607 is executed directly after step 605 is completed.

Step 707: the relay UE2 sends a relay access response message to the base station when the relay UE2 determines that the D2D UE1 is allowed to access and the relay UE2 can forward the D2D data to the D2D UE 2;

Step 708: after receiving the relay access response message, the base station sends a relay UE replacement command to the D2D UE1 to command the D2D UE1 to access the new relay UE;

Step 709: after receiving the relay UE replacement command, the D2D UE1 initiates a relay access request process to the relay UE2, namely, sends a relay access request message to the relay UE 2;

here, the relay access request message may include: identification information of the D2D UE1, identification information of target D2D UEs (including at least D2D UE2) of the D2D UE1, communication service QoS requirement information of the D2D UEs, D2D security capability information, D2D security-related parameter information, D2D communication group identification information of the D2D UE1, D2D relay type requested by the D2D UEs, priority information of the D2D UEs 1, priority information of D2D communication groups where the D2D UEs 1 are located, priority information of D2D communication services of the D2D UEs 1, and configuration information of D2D communication between the D2D UEs 1 and relay UEs 2.

The D2D relay type requested by the D2D UE may include: UE to UE relay, UE to network relay.

After the relay UE2 receives the relay access request message, if the relay UE2 does not perform step 506, it needs to perform corresponding admission control, i.e. perform the operation of step 506. In other words, after receiving the relay access request message, the relay UE2 needs to determine whether to allow the D2D UE1 to communicate with the D2DUE2 through the relay of the relay UE2 in the D2D. Specifically, the relay UE2 may determine whether to allow the D2D UE1 access according to the relay capability, the transceiving capability, the number of the accessed D2D UEs, the priority information, and the information such as the communication service QoS requirement of the D2D UE, and perform the D2D communication with the D2D UE2 through the relay of the relay UE 2.

Step 710: when the relay UE2 determines that the relay UE1 is allowed to access, a relay access response message is sent to the D2D UE 1;

here, the relay access response message may include: identification information of the D2D UE1, identification information of a target D2D UE of the D2D UE1 (i.e., D2D UE2), and configuration information of D2D communication between the D2D UE1 and the relay UE 2. The configuration information of D2D communication between the D2D UE1 and the relay UE2 may include D2D communication bearer configuration information, security-related configuration information, and the like.

Step 711: after determining that the D2D UE1 is allowed to access, the relay UE2 sends relay UE update information to a target D2DUE (including at least D2D UE2) of the D2D UE1, so as to update relay node information maintained at the target D2D UE (i.e., D2D UE 2);

wherein the relay UE update information may include: identification information of the D2D UE1, identification information of a target D2D UE of the D2D UE1 (i.e., D2D UE2), identification information of a new D2D relay node (i.e., relay UE2), and configuration information of D2D communication between the relay UE2 and the D2D UE 2.

Step 712: after receiving the D2D relay node update information, the D2D UE2 updates the relay node information maintained by itself, and sends relay UE update confirmation information to the relay UE 2;

Step 713: after the D2D UE1 accesses the relay UE2, the relay UE2 sends a D2D UE access completion message to the base station;

here, the D2D UE access completion message may include: identification information of the D2D UE1, identification information of a target D2D UE of the D2DUE1 (i.e., D2D UE2), and identification information of a new D2D relay node (i.e., relay UE 2).

Step 714: after receiving the D2D UE access completion message, the base station sends a relay connection release message to an original D2D relay node (i.e., relay UE1) of the D2D UE1 to release the connection between the D2D UE1 and the relay UE 1; accordingly, the relay UE1 releases the relevant context information of the relay UE1 after receiving the relay connection release message;

here, the relay connection release message may include: a release indication, identification information of the D2D UE1, identification information of a target D2D UE of the D2D UE1 (i.e., D2D UE2), and a release reason. Optionally, the relay UE1, after receiving the relay connection release message, may send a relay connection release message to the D2D UE1, instructing the D2D UE1 to release its connection with the relay UE 1.

Step 715: the relay UE1 replies to the base station with a relay connection release confirm message.

Here, in practical application, this step is an optional step.

It should be noted that: the method of the embodiment is also applicable to the relay scenario from the UE to the network. When the scheme of the present embodiment is used in the UE-to-network relay scenario, the target D2D UE identification information of the relay UE1 need not be included in the message of the above step, and the relay UE update procedure, i.e., steps 710 and 711, need not be performed.

EXAMPLE six

The application scenario of this embodiment is as follows: D2D UE1, D2D UE2, relay UE1, and relay UE2 are D2D UEs, which are located inside or outside the coverage of the cellular communication network; the relay UE1 and the relay UE2 may serve as relay nodes to provide relay services for other D2D UEs, and in the method of the embodiment, the replacement of the relay UE does not involve signaling interaction with the base station. Note that the D2D UE may connect to different relay UEs, sending D2D data to different target D2DUE through different relay UEs.

In this embodiment, a method for replacing a relay node in a scenario from D2D UE to UE relay is shown in fig. 8, and includes the following steps:

step 801: D2D UE1 and D2D UE2 communicate D2D through relay UE1 as a relay node, and D2D UE1 determines that a replacement of the relay UE is required;

In practical applications, in the first mode, before the D2D UE1 performs the relay UE discovery and measurement procedure, the D2D UE1 may obtain the D2D discovery resource configuration information used by the relay UE from the base station (for example, obtained through SIB) through active transmission by the base station or from ProSe function through a pre-configuration mode.

Step 802: D2D UE1 performed relay UE discovery and measurement procedures;

Step 803: the D2D UE1 determining one or more candidate new relay UEs from the received relay UE discovery message, or measurements of the discovery message;

for example, the D2D UE1 selects relay UEs with better signal quality among the discovered relay UEs as candidate relay nodes.

Here, the D2D UE1 determines the relay UE2 as a candidate new relay node in the present embodiment.

Step 804: D2D UE1 initiates a relay access request procedure to relay UE2, i.e., sends a relay access request message to relay UE 2;

here, the relay access request message may include: identification information of D2D UE1, identification or identification list information (e.g., identification of D2D UE2) of target D2D UE of D2D UE1, communication traffic QoS requirement information of D2DUE, D2D security capability information, D2D security related parameter information, D2D communication group identification information of D2D UE1, D2D relay type requested by D2D UE1, priority information of D2D UE1, priority information of D2D communication group where D2D UE1 is located, priority information of D2 686 2D communication traffic of D2D UE1, and configuration information of D2D communication between D2D UE1 and relay UE 2.

The D2D relay type requested by the D2D UE includes: UE-to-UE relay, and UE-to-network relay.

Step 805: relay UE2 performs corresponding admission control;

specifically, after receiving the relay access request message, the relay UE2 determines whether to allow the D2D UE1 to perform D2D communication with the D2D UE2 through relaying of the relay UE 2.

Here, the relay UE2 may determine whether to allow the D2D UE1 access according to its own relay capability, transceiving capability, the number of D2D UEs that have accessed, priority information, and information such as traffic QoS requirements of the D2D UEs.

In practical application, the relay UE2 may detect a D2DUE near itself by monitoring the D2D discovery signal, and acquire identification information thereof; accordingly, the relay UE2 may determine from its detected nearby D2D UE information whether D2D communication data of the D2D UE1 can be forwarded to a target D2D UE of the D2D UE 1.

Step 806: the relay UE2 sends a relay access response message to the D2D UE1 when determining that the D2D UE1 is allowed to access and the relay UE2 can forward the D2D data to a target D2D UE of the D2D UE 1;

here, the relay access response message may include: identification information of the D2D UE1, identification or identification list information of a target D2D UE (e.g., D2D UE2) of the D2D UE1 that may be routed through the relay UE2, and configuration information of D2D communications between the D2D UE1 and the relay UE 2.

In practice, if the relay UE2 determines that the D2D UE1 is not allowed to access, or the relay UE2 cannot forward the D2D data to the target D2D UE of the D2D UE1, then a reject message is replied to the D2D UE 1.

Step 807: after receiving the relay UE access response message, the D2D UE1 sends a relay UE connection release message to the original D2D relay node (relay UE1) to release the connection between the relay UE and the relay UE 1; accordingly, the relay UE1 releases the relevant context information of the relay UE1 after receiving the relay connection release message;

Step 808: the D2D UE1 sends relay UE update information to the D2D UE2 through a new D2D relay node (relay UE2) for updating relay node information maintained at the target D2D UE (i.e., D2D UE 2);

In practice, this step may occur before or after step 807.

Step 809: after receiving the relay UE update information, the D2D UE2 updates the relay node information maintained by itself, and sends relay UE update confirmation information to the D2D UE1 through a new D2D relay node (relay UE 2).

It should be noted that: the method of the embodiment is also applicable to the relay scenario from the UE to the network. When the scheme of the present embodiment is used in the UE-to-network relay scenario, the message of the above step does not need to include the target D2D UE identification information of the relay UE1, and the relay UE update procedure, i.e., steps 808 and 809, does not need to be performed.

EXAMPLE seven

The application scenario of this embodiment is as follows: the D2D UE1, D2D UE2, relay UE1, relay UE2, and relay UE3 are all within cellular communication network coverage and are D2D UEs, and the relay UE1, relay UE2, and relay UE3 may serve as relay nodes to relay other D2D UEs. Among them, the relay UE3 may serve as a central control node to which a plurality of relay UEs (e.g., relay UE1, relay UE2) are connected. The central control node may obtain relay-related information of relay nodes in its vicinity by listening to the relay node discovery message or broadcast information, or the central control node may obtain its relay-related information from the relay nodes. Note that the D2D UE may connect to different relay UEs, sending D2D data to different target D2D UEs through different relay UEs.

In this embodiment, a method for replacing a relay node in a scenario from D2D UE to UE relay is shown in fig. 9, and includes the following steps:

step 901: D2D UE1 and D2D UE2 communicate D2D through relay UE1 as a relay node, and D2D UE1 determines that a replacement of the relay UE is required;

In a third mode, the central control node sends a D2D relay node discovery trigger threshold value to a D2D UE 1; the D2D relay node discovery trigger threshold value is a measurement threshold value of the D2D UE1 for the accessed relay UE 1; when the measurement value of the relay UE1 is less than the D2D relay node discovery trigger threshold value, the D2D UE1 turns on relay UE discovery.

Step 902: D2D UE1 performed relay UE discovery and measurement procedures;

Step 903: the D2D UE1 sends relay UE discovery results or measurement information to the base station;

Step 904: the base station determines that the relay UE needs to be replaced for the D2DUE1 according to the received relay UE discovery result or the received measurement information;

here, optionally, the base station selects one or more relay UEs for the D2D UE1 as candidate new relay nodes according to the received relay UE discovery result or measurement information.

Step 905: the base station sends a relay selection (access) request message to a relay UE3 (central control node);

here, the message may contain the discovery result or measurement information received by the base station from the D2D UE1 in step 803.

In practical application, the message may further include one or a combination of the following: identification information of D2D UE1, identification or identification list information of target D2D UEs of D2D UE1 (e.g., identification of D2D UE2), target (candidate) relay UE identification information selected for D2D UE1, communication traffic QoS requirement information of D2D UEs, D2D security capability information, D2D security-related parameter information, D2D communication group identification information of D2D UE1, D2D relay type requested by D2D UE1, priority information of D2D UE1, priority information of D2D communication group where D2D UE1 is located, priority information of D2D communication traffic of D2D UE1, and configuration information of D2D communication between D2D UE1 and relay UE 2.

Step 906: the base station does not select a new candidate relay UE for the D2D UE1, the relay UE3 selects a new candidate relay UE according to the information received in step 905;

for example, the relay UE3 selects a relay UE with better signal quality as a candidate relay node among the relay UEs discovered by the UE.

Step 907: the relay UE3 transmits a relay access request message to a candidate new relay UE (relay UE 2);

here, the relay access request message may include: identification information of D2D UE1, identification or identification list information (e.g., identification of D2D UE2) of target D2D UEs of D2D UE1, communication traffic QoS requirement information of D2D UEs, D2D security capability information, D2D security-related parameter information, D2D communication group identification information of D2D UE1, D2D relay type requested by D2D UE1, priority information of D2D UE1, priority information of D2D communication group in which D2D UE1 is located, priority information of D2D communication traffic of D2D UE1, and configuration information of D2D communication between D2D UE1 and relay UE 2.

Step 908: after receiving the relay access request message, the relay UE2 needs to perform admission control to determine whether to allow the D2D UE1 to perform D2D communication with a target D2D UE of the D2D UE1 through the relay of the relay UE 2;

specifically, the relay UE2 may determine whether to allow the D2DUE1 access according to its own relay capability, transceiving capability, the number of D2DUE that have been accessed, priority information, communication traffic QoS requirement of the D2D UE, and other information.

In practical application, relay UE may detect a D2DUE nearby itself by monitoring a D2D discovery signal, and acquire identification information thereof; accordingly, the relay UE2 may determine from the detected nearby D2D UE information whether D2D communication data of the D2D UE1 can be forwarded to a target D2D UE of the D2D UE 1.

Step 909: the relay UE2 sends a relay access response message to the relay UE3 when determining that the D2D UE1 is allowed to access and the relay UE2 can forward the D2D data to a target D2D UE of the D2D UE 1;

here, the relay access response message may include: identification information of the D2D UE1, identification or identification list information of a target D2D UE (e.g., D2D UE2) of the D2D UE1 that may be routed through the relay UE2, and configuration information of D2D communication between the D2D UE1 and the relay UE2, an IP address allocated by the relay UE2 for the D2D UE 1.

If the relay UE2 determines that the D2D UE1 is not allowed access, or the relay UE2 is unable to forward the D2D data to the target D2D UE of the D2D UE1, then a reject message is replied to the relay UE 3.

Step 910: after receiving the relay access response message, relay UE3 sends a relay selection (access) confirmation message to the base station;

here, the acknowledgement message may include: identification information of the D2D UE1, target relay UE identification information, identification or identification list information of target D2D UEs (e.g., D2D UE2) of the D2D UE1 that can be routed through the relay UE2, and configuration information of D2D communication between the D2D UE1 and the relay UE2, IP addresses allocated by the relay UE2 for the D2D UE 1.

Step 911: the base station sends a relay UE change command to the D2D UE1 to command the D2D UE1 to access the new relay UE;

here, the relay UE change command may include: identification information of the new D2D relay node, identification information of the D2DUE1, identification or identification list information of a target D2D UE (e.g., D2D UE2) of the D2D UE1 that can be routed through the new D2D relay node, and configuration information of D2D communication between the D2D UE1 and the relay UE2, an IP address allocated by the relay UE2 for the D2D UE 1.

Step 912: transmitting a relay UE change confirm message to the base station if the D2D UE1 confirms D2D communication with the D2D UE2 through the relay of the relay UE 2;

step 913: the base station sends a relay connection release message to the original relay UE (namely, relay UE1) of the D2D UE1 after receiving the relay UE replacement confirmation; accordingly, the relay UE1 releases the relevant context information of the relay UE1 after receiving the relay connection release message;

specifically, the relay connection release message may include: a release indication, identification information of the D2D UE1, identification information of a target D2D UE (i.e., D2D UE2) of the D2D UE1, a release reason.

In actual application, the relay connection release message may also be sent to the relay UE1 by the relay UE 3; or, the base station sends a relay connection release message to the relay UE3, and the relay UE3 sends the relay connection release message to the relay UE 1.

Optionally, the relay UE1 may send a relay connection release message to the D2D UE1 after receiving the relay connection release message, and instruct the D2D UE1 to release the connection between the D2D UE1 and the relay UE 1; alternatively, the relay UE1 may also determine whether to release its connection with the D2D UE1 based on a self-maintained timer. Specifically, the relay UE1 starts/restarts the timer each time it receives a D2D communication packet sent by the D2D UE1, releases its connection with the D2D UE1 when the timer expires, and deletes the D2D UE1 related context.

Step 914: the D2D UE1 sends relay UE update information to the D2D UE2 through the new D2D relay node relay UE2 for updating the relay node information maintained at the target D2D UE (i.e., D2D UE 2);

Step 915: after receiving the D2D relay node update information, the D2D UE2 updates the relay node information maintained by itself, and sends relay UE update confirmation information to the D2D UE1 through a new D2D relay node relay UE 2.

It should be noted that: the method of the embodiment is also applicable to the relay scenario from the UE to the network. When the scheme of the present embodiment is used in the UE-to-network relay scenario, the target D2D UE identification information of the relay UE1 need not be included in the message of the above step, and the relay UE update procedure need not be performed, i.e., steps 914 and 915 need not be performed.

Example eight

The application scenario of this embodiment is as follows: the D2D UE1, the D2D UE2, the relay UE1, the relay UE2 and the relay UE3 are all D2D UEs, and the relay UE1, the relay UE2 and the relay UE3 can all serve as relay nodes to provide relay services for other D2D UEs. Among them, the relay UE3 may serve as a central control node to which a plurality of relay UEs (e.g., relay UE1, relay UE2) are connected. The central control node may obtain relay-related information of relay nodes in its vicinity by listening to the relay node discovery message or broadcast information, or the central control node may obtain its relay-related information from the relay nodes. Note that the D2D UE may connect to different relay UEs, sending D2D data to different target D2D UEs through the different relay UEs. It should be noted that: the central control node may be served by a relay UE (relay UE3 in this embodiment) or may be served by a base station. In this embodiment, the relay UE3 is taken as a central control node as an example.

In this embodiment, a method for replacing a relay node in a scenario from D2D UE to UE relay is shown in fig. 10, and includes the following steps:

step 1001: D2D UE1 and D2D UE2 communicate D2D through relay UE1 as a relay node, and D2D UE1 determines that a replacement of the relay UE is required;

In practical application, in the first mode, before the D2D UE1 performs the relay UE discovery and measurement process, the D2D UE1 obtains the D2D discovery resource configuration information used by the relay UE from the relay UE1 through the active transmission of the relay UE 1; or after the D2D UE1 determines that the relay UE discovery and measurement process needs to be performed, the D2D relay UE discovery indication information is sent to the relay UE1, and the relay UE1 sends the D2D discovery resource configuration information used by the relay UE to the D2D UE1 after receiving the discovery indication information. The D2D discovery resource configuration information used by the relay UE1 is obtained from the relay UE1, and may include, for example, information such as frequency point, subframe, PRB, and relay UE identity.

Step 1002: D2D UE1 performed relay UE discovery and measurement procedures;

Step 1003: the D2D UE1 sends relay UE discovery results or measurement information to the relay UE 1;

here, the discovery result or the measurement information may include: relay node identification information (e.g., ProSe ID, etc.) of D2D relay discovery message received by D2D UE1, measurement results (e.g., signal strength, etc.) of discovery message of D2D UE1 on received D2D relay node.

In practice, the D2D UE1 may also send its own geographical location information to the relay UE 1.

In practical application, the D2D UE1 may further transmit identification information of the D2D UE1, QoS requirement information of communication service of the D2D UE, D2D security capability information, D2D security-related parameter information, D2D communication group identification information of the D2D UE1, priority information of the D2D UE1, priority information of a D2D communication group where the D2D UE1 is located, priority information of D2D communication service of the D2D UE1, a requested D2D relay type, and identification information of a target D2D UE to the relay UE 1.

Wherein, the D2D relay type includes: UE to UE relay, UE to network relay.

Step 1004: the relay UE1 determines that the relay UE needs to be replaced for the D2D UE1 according to the received relay UE discovery result or the measurement information, and the relay UE1 sends a relay UE replacement request message to a central control node (relay UE 3);

here, the relay UE1 may select one or more relay UEs as candidate new relay nodes for the D2D UE1 according to the relay UE discovery result or measurement information. For example, the relay UE1 selects a relay UE with better signal quality as a candidate relay node among the relay UEs discovered by the UE.

The relay UE change request message may include the discovery result and measurement information received by the relay UE1 from the D2D UE1 in step 903.

The relay UE change request message may further include one or a combination of the following: identification information of D2D UE1, identification or identification list information of target D2D UEs of D2D UE1 (e.g., identification of D2D UE2), target (candidate) relay UE identification information selected for D2D UE1, communication traffic QoS requirement information of D2D UEs, D2D security capability information, D2D security-related parameter information, D2D communication group identification information of D2D UE1, D2D relay type requested by D2D UE1, priority information of D2D UE1, priority information of D2D communication group where D2D UE1 is located, priority information of D2D communication traffic of D2D UE1, and configuration information of D2D UE1 and D2D communication between relay UE 2.

Step 1005: the relay UE1 does not select a candidate new relay UE for the D2D UE1, then the central control node (relay UE3) selects a candidate new relay UE according to the information received in step 904;

Step 1006: the relay UE3 transmits a relay access request message to a candidate new relay UE (relay UE 2);

The communication service QoS requirement information of the D2D UE may include QCI, ARP, GBR, MBR, and other information.

The D2D relay types requested by the D2D UE include: UE to UE relay, UE to network relay.

Step 1007: after receiving the relay access request message, the relay UE2 needs to perform admission control to determine whether to allow the D2D UE1 to perform D2D communication with a target D2D UE of the D2D UE1 through the relay of the relay UE 2;

specifically, the relay UE2 may determine whether to allow the D2D UE1 to access according to the relay capability, the transceiving capability, the number of the accessed D2D UEs, the priority information, the communication service QoS requirement of the D2D UE, and other information.

In practical application, the relay UE2 may detect a D2DUE near itself by monitoring the D2D discovery signal, and acquire identification information thereof; accordingly, the relay UE2 may determine whether it is possible to forward D2D communication data of the D2D UE1 to a target D2D UE of the D2D UE1 according to the nearby D2D UE information detected by itself.

Step 1008: the relay UE2 sends a relay access response message to the relay UE3 when determining that the D2D UE1 is allowed to access and the relay UE2 can forward the D2D data to a target D2D UE of the D2D UE 1;

here, the relay access response message may include: identification information of the D2D UE1, identification or identification list information of a target D2D UE (e.g., D2D UE2) of the D2D UE1 that may be routed through the relay UE2, configuration information of D2D communications between the D2D UE1 and the relay UE2, an IP address allocated by the relay UE2 for the D2D UE 1.

If the relay UE2 does not allow the D2D UE1 access, or the relay UE2 cannot forward the D2D data to the target D2D UE of the D2D UE1, a reject message is replied to the relay UE 3.

Step 1009: after receiving the relay access response message, the relay UE3 sends a relay UE replacement confirmation message to the relay UE 1;

here, the relay UE change confirm message may include identification information of the D2D UE1, target relay UE identification information, identification or identification list information of a target D2D UE (e.g., D2D UE2) of the D2D UE1 that may be routed through the relay UE2, and configuration information of D2D communication between the D2D UE1 and the relay UE2, an IP address allocated by the relay UE2 for the D2D UE 1.

Step 1010: the relay UE1 sends a relay UE change command to the D2D UE1 to command the D2D UE1 to access the new relay UE;

Step 1011: when the D2D UE1 confirms that D2D communication is performed with the D2D UE2 through relay of the relay UE2, transmitting a relay UE replacement confirmation message to the relay UE 1;

step 1012: the relay UE1 releases the connection with the D2D UE1 after receiving the relay UE replacement confirmation;

here, in actual use, the relay UE1 may send a relay connection release message to the D2D UE 1; alternatively, the D2D UE1 or relay UE1 releases the connection between the relay UE1 and the D2DUE1 after the self-maintained timer expires.

Specifically, the relay UE1/D2D UE1 starts/restarts the timer each time it receives a D2D communication data packet sent by the D2D UE1/relay UE1, releases the connection between the relay UE1 and the D2D UE1 when the timer expires, and deletes the context related to the D2D UE 1.

The relay connection release message may include: a release indication, identification information of the D2D UE1, identification information of a target D2D UE of the D2D UE1 (i.e., D2D UE2), a release reason. Alternatively, the relay connection release message may be sent by the central control node (relay UE3) to the relay UE1, and then by the relay UE1 to the D2D UE 1.

Step 1013: the D2D UE1 sends relay UE update information to the D2D UE2 through the new D2D relay node relay UE2 for updating the relay node information maintained at the target D2D UE (i.e., D2D UE 2);

Step 1014: after receiving the D2D relay node update information, the D2D UE2 updates the relay node information maintained by the D2D UE, and sends relay UE update confirmation information to the D2D UE1 through a new D2D relay node relay UE 2.

Wherein the relay UE update confirmation information includes: identification information of the D2D UE1, identification information of a target D2D UE of the D2D UE1 (i.e., D2D UE2), identification information of a new D2D relay node (i.e., relay UE 2).

It should be noted that: the method of the embodiment is also applicable to the relay scenario from the UE to the network. When the scheme of the present embodiment is used in the UE-to-network relay scenario, the target D2D UE identification information of the relay UE1 need not be included in the message of the above step, and the relay UE update procedure need not be performed, i.e., steps 1013 and 1014 need not be performed.

Example nine

The application scenario of this embodiment is as follows: the D2D UE1, D2D UE2, relay UE1 and relay UE2 are D2D UEs, and the relay UE1 and the relay UE2 can serve as relay nodes to provide relay service for other D2D UEs. Note that the D2D UE may connect to different relay UEs, sending D2D data to different target D2D UEs through the different relay UEs.

In this embodiment, a method for replacing a relay node in a scenario from D2D UE to UE relay is shown in fig. 11, and includes the following steps:

step 1101: D2D UE1 and D2D UE2 communicate D2D through relay UE1 as a relay node, and D2D UE1 determines that a replacement of the relay UE is required;

Step 1102: D2D UE1 performed relay UE discovery and measurement procedures;

Step 1103: the D2D UE1 sends relay UE discovery results or measurement information to the relay UE 1;

here, the discovery result or the measurement information may include: relay node identification information (e.g., ProSe ID) of the D2D relay discovery message received by the D2D UE, and measurement results (e.g., signal strength) of the D2D UE on the discovery message of the received D2D relay node.

Optionally, the D2D UE1 may also send its own geographical location information to the relay UE 1.

Optionally, the D2D UE1 may further send the identification information of the D2D UE1, the communication service QoS requirement information of the D2D UE, the D2D security capability information, the D2D security-related parameter information, the D2D communication group identification information of the D2D UE1, the priority information of the D2D UE1, the priority information of the D2D communication group where the D2D UE1 is located, the priority information of the D2D communication service of the D2D UE1, the requested D2D relay type, and the identification information of the target D2D UE to the relay UE 1.

Wherein, the D2D relay type includes: UE to UE relay, UE to network relay.

Step 1104: the relay UE1 determines that the relay UE needs to be replaced for the D2D UE1 according to the relay UE discovery result or the measurement information;

optionally, the relay UE1 selects one or more relay UEs as candidate new relay nodes for the D2D UE1 according to the relay UE discovery result or measurement information received from the D2D UE 1. For example, the relay UE1 selects a relay UE with better signal quality as a candidate relay node among the relay UEs discovered by the UE.

Among them, the Relay UE1 may detect Relay UEs nearby itself and acquire their identification information by listening to the D2D discovery signal.

Step 1105: the relay UE1 transmits a relay access request message to a candidate new relay UE (relay UE 2);

here, the relay access request message may contain the discovery result or measurement information that the relay UE1 received from the D2D UE1 in step 1003.

The relay access request message may also contain one or a combination of the following: identification information of D2D UE1, identification or identification list information of target D2D UEs of D2D UE1 (e.g., identification of D2D UE2), identification information of target (candidate) relay UEs selected for D2D UE1, communication traffic QoS requirement information of D2D UEs, D2D security capability information, D2D security-related parameter information, D2D communication group identification information of D2D UE1, D2D relay type requested by D2D UE1, priority information of D2D UE1, priority information of D2D communication group where D2DUE1 is located, priority information of D2D communication traffic of D2D UE1, and configuration information of D2D communication between D2D UE1 and relay UE 2.

Step 1106: after receiving the relay access request message, the relay UE2 needs to perform admission control to determine whether to allow the D2D UE1 to perform D2D communication with a target D2D UE of the D2D UE1 through the relay of the relay UE 2;

specifically, the relay UE2 may determine whether to allow the D2D UE1 to access according to the relay capability, the transceiving capability, the number of the D2D UEs that have accessed, the priority information, and the communication service QoS requirement of the D2D UE.

Optionally, the relay UE2 may detect a D2D UE nearby itself by monitoring the D2D discovery signal, and acquire identification information thereof; accordingly, the relay UE2 may determine from its detected nearby D2D UE information whether D2D communication data of the D2D UE1 can be forwarded to a target D2D UE of the D2D UE 1.

Step 1107: the relay UE2 sends a relay access response message to the relay UE1 when determining that the D2D UE1 is allowed to access and the relay UE2 may forward the D2D data to a target D2D UE of the D2D UE 1;

here, the relay access response message may include: identification information of the D2D UE1, identification or identification list information of a target D2D UE (e.g., D2D UE2) of the D2D UE1 that can be routed through the relay UE2, and configuration information of D2D communication between the D2D UE1 and the relay UE2, an IP address allocated by the relay UE2 for the D2D UE 1.

If the relay UE2 determines that the D2D UE1 is not allowed access, or the relay UE2 cannot forward the D2D data to the target D2D UE of the D2D UE1, then a reject message is replied to the relay UE 1.

Step 1108: after receiving the relay UE access response message, the relay UE1 sends a relay UE replacement command message to the D2D UE1 to command the D2D UE1 to access the new relay UE;

Step 1109: when the D2D UE1 confirms that D2D communication is performed with the D2D UE2 through relay of the relay UE2, transmitting a relay UE replacement confirmation message to the relay UE 1;

step 1110: the relay UE1 releases the connection between itself and the D2D UE1 after receiving the relay UE replacement confirmation;

here, optionally, the relay UE1 may send a relay connection release message to the D2D UE 1. Alternatively, the D2D UE1 or relay UE1 releases the connection between the relay UE1 and the D2D UE1 after the self-maintained timer expires. Specifically, the relay UE1/D2D UE1 starts/restarts the timer each time it receives a D2D communication data packet sent by the D2D UE1/relay UE1, releases the connection between the relay UE1 and the D2DUE1 after the timer expires, and deletes the context related to the D2D UE 1.

Wherein the relay connection release message may include: a release indication, identification information of the D2D UE1, identification information of a target D2D UE of the D2D UE1 (i.e., D2D UE2), and a release reason.

Step 1111: the D2D UE1 sends relay UE update information to the D2D UE2 through the new D2D relay node relay UE2 for updating the relay node information maintained at the target D2D UE (i.e., D2D UE 2);

Step 1112: after receiving the D2D relay node update information, the D2D UE2 updates the relay node information maintained by itself, and sends relay UE update confirmation information to the D2D UE1 through a new D2D relay node relay UE 2;

wherein the relay UE update confirmation information includes: identification information of the D2D UE1, identification information of a target D2D UE of the D2D UE1 (i.e., D2D UE2), and identification information of a new D2D relay node (i.e., relay UE 2).

It should be noted that: the method of the embodiment is also applicable to the relay scenario from the UE to the network. When the scheme of the present embodiment is used in the UE-to-network relay scenario, the message of the above step does not need to include the target D2D UE identification information of the relay UE1, and the relay UE update procedure does not need to be performed, i.e., steps 1111 and 1112 do not need to be performed.

Example ten

The application scenario of this embodiment is as follows: D2D UE1, relay UE1, and relay UE2 are all within cellular communication network coverage and are all D2D UEs; also, the relay UE1 and the relay UE2 may serve as relay nodes to provide relay services for other D2D UEs.

In this embodiment, a method for replacing a relay node in a scenario from D2D UE to UE relay is shown in fig. 12, and includes the following steps:

step 1201: the D2D UE1 accesses the network for cellular communication through the relay UE1 as a relay node, and the D2D UE1 determines that replacement of the relay UE is required;

in the first mode, when the D2D UE1 or relay UE1 moves, the D2D UE1 detects that the signal quality between the D2D UE1 and the relay UE1 is poor, and at this time, the D2D UE1 needs to search for a new relay node, then the relay UE discovery and measurement process is executed;

in a second manner, the relay UE1 may trigger a relay UE replacement of the D2D UE1, for example, when the power of the relay UE1 is insufficient, the relay UE1 may send the power shortage, or suspend the relay indication, or relay status indication, or relay connection release indication through the broadcast or unicast communication manner of the D2D, so as to trigger the D2D UE1 to perform the relay UE replacement, i.e., trigger the D2D UE1 to perform the relay UE discovery and measurement procedure.

In practical applications, in the first mode, before the D2D UE1 performs relay UE discovery and measurement procedures, the D2D UE1 may also obtain (e.g., obtain through SIB) the D2D discovery resource configuration information used by the relay UE from the base station through active transmission by the base station; or after determining that the relay UE discovery process needs to be executed, the D2D UE1 sends D2D relay UE discovery indication information to the base station, and after receiving the discovery indication information, the base station sends D2D discovery resource configuration information used by the relay UE to the D2D UE 1.

Here, the D2D discovery resource configuration information may include: information such as frequency point, subframe, PRB and relayUE identification

Step 1202: D2D UE1 performs a relay UE discovery procedure;

here, the relay UE discovery process may adopt Model a or Model B modes. In the model A mode, a relay UE broadcasts a D2D discovery message; the D2D discovery message may include identification information of the relay UE, a plmn id to which a radio carrier used for D2D communication between the D2D UE and the relay UE belongs, connection related information (for identifying connection information, such as APN information, that can be provided by the UE-to-Network relay UE), and relay status information (such as relay suspension, power shortage, etc.); in the Model B scheme, the D2D UE broadcasts the relay node discovery message, and the relay UE serving as the relay node receives the relay node discovery message and then transmits a response message to the D2D UE.

In practical applications, the D2D UE1 obtains discovery or measurement related resource configuration information used by the relay UE from the base station or prosecution before performing the relay UE discovery procedure. The resource configuration information may include: D2D used by the relay UE discovers time and/or frequency domain resource information, and identification information of the relay UE. The D2D UE1 may perform discovery or measurement of relay UEs according to the received resource configuration information.

Step 1203: the D2D UE1 sends relay UE discovery results or measurement information to the base station;

specifically, the discovery result or the measurement information may include: relay node identification information (e.g., ProSe ID) of D2D relay discovery message received by D2D UE1, measurement (e.g., signal strength) of discovery message of D2D relay node received by D2D UE 1.

Alternatively, the D2D UE1 may send its own geographical location information to the base station.

Optionally, the D2D UE1 may further send the identification information of the D2D UE1, the QoS requirement information of the communication service of the D2D UE1, the D2D security capability information, the D2D security-related parameter information, the D2D communication group identification information of the D2D UE1, the priority information of the D2D UE1, the priority information of the D2D communication group where the D2D UE1 is located, the priority information of the D2D communication service of the D2D UE1, and the requested D2D relay type to the base station. Wherein, the D2D relay type includes: UE to UE relay, UE to network relay.

Step 1204: the base station selects one or more relay UEs for the D2D UE1 as candidate new relay nodes according to the received relay UE discovery result or the measurement information;

Here, it is assumed that the candidate new relay node is relay UE 2.

Step 1205: the base station sends a relay access request message to the relay UE 2;

here, the relay access request message may include: identification information of D2D UE1, communication service QoS requirement information of D2D UE1, D2D security capability information, D2D security related parameter information, D2DUE 1D 2D communication group identification information, D2D relay type requested by D2D UE1, priority information of D2D UE1, priority information of D2D D2D communication group where UE1 is located, priority information of D2D communication service of D2D UE1, and configuration information of D2D communication between D2D UE1 and relay UE 2.

The QoS requirement information of the D2D UE may include QCI, ARP, GBR, MBR, and other information.

The D2D UE1 requested D2D relay types include: UE to UE relay, UE to network relay.

Step 1206: after receiving the relay access request message, the relay UE2 needs to perform admission control to determine whether to allow the D2D UE1 to perform D2D communication with a target D2D UE of the D2D UE1 through the relay of the relay UE 2;

Step 1207: when the relay UE2 determines that the D2D UE1 is allowed to access, sending a relay access response message to the base station;

here, the relay access response message may include: identification information of the D2D UE1, configuration information of D2D communication between the D2D UE1 and the relay UE2, and an IP address allocated by the relay UE2 for the D2D UE 1.

If the relay UE2 does not allow the D2D UE1 access, a reject message is replied to the base station, which may select other candidate relay UEs for the D2D UE 1.

Step 1208: after receiving the relay access response message, the base station sends a relay UE replacement command to the D2D UE1 to command the D2D UE1 to access the new relay UE;

here, the relay UE change command may include: identification information of a new D2D relay node (i.e., relay UE2), identification information of D2D UE1, configuration information of D2D communication between D2D UE1 and relay UE2, and an IP address allocated by the relay UE2 to the D2D UE 1.

Step 1209: D2D UE1 sending relay UE change confirmation to the base station when confirming cellular communication through the relay access network of relay UE 2;

step 1210: the base station sends a relay connection release message to the original relay UE (namely, relay UE1) of the D2D UE1 after receiving the replacement confirmation of the relay UE; accordingly, the relay UE1 releases the relevant context information of the relay UE1 after receiving the relay connection release message;

here, the relay connection release message may include: a release indication, identification information of the D2D UE1, a release reason, and the like.

Optionally, after receiving the relay connection release message, the relay UE1 may send a relay connection release message to the D2D UE1, instructing the D2D UE1 to release the connection between the relay UE1 and the UE 1; alternatively, the relay UE1 may also determine whether to release its connection with the D2D UE1 based on a self-maintained timer. Specifically, the relay UE1 starts/restarts the timer each time it receives a D2D communication packet sent by the D2D UE1, releases its connection with the D2D UE1 when the timer expires, and deletes the D2D UE1 related context.

EXAMPLE eleven

The application scenario of this embodiment is as follows: the relay UE1, the relay UE2 are both within cellular communication network coverage, the D2D UE is at the edge of or outside of cellular network coverage; also, the relay UE1 and the relay UE2 may serve as relay nodes to provide relay services for other D2D UEs.

In this embodiment, a method for replacing a relay node in a scenario from D2D UE to UE relay is shown in fig. 13, and includes the following steps:

step 1301: the D2D UE accesses the network for cellular communication through the relay UE1 as a relay node, and the D2D UE1 determines that replacement of the relay UE is required;

here, the manner in which the D2D UE determines that the relay UE needs to be replaced may be any one of the following:

in the first mode, when the D2D UE or the relay UE1 moves, the D2D UE detects that the signal quality between the D2D UE and the relay UE1 is poor, and the D2D UE needs to search for a new relay node, the relay UE discovery and measurement process is executed;

second, relay UE replacement of the D2D UE may be triggered by the relay UE1, for example, when the relay UE1 is low in power, the relay UE1 may send a low power, suspend relay indication, relay status indication, or relay connection release indication through D2D broadcast or unicast communication.

Step 1302: D2D UE performs relay UE discovery and measurement procedure;

here, the relay UE discovery and measurement process can adopt two modes, i.e. Model a or Model B. In the Model A mode, a relay UE broadcasts a D2D discovery message; the D2D discovery message may include identification information of the relay UE, PLMN ID to which a radio carrier used for D2D communication between the D2D UE and the relay UE belongs, connection related information (for identifying connection information, such as APN information, that can be provided by the UE-to-Network relay UE), relay status information (such as relay suspension, power shortage, etc.); in the model b scheme, the D2D UE broadcasts the relay node discovery message, and the relay UE serving as the relay node receives the relay node discovery message and then transmits a response message to the D2D UE.

Optionally, the D2D UE acquires configuration information related to relay node discovery or measurement from the base station or ProSe function before performing the relay UE discovery procedure. Specifically, the configuration information may include: D2D used by the D2D relay node discovers time and/or frequency domain resource information, identification information of the relay node UE, etc. The D2D UE1 may perform relay node discovery or measurement according to the received configuration information.

Step 1303: the D2D UE sends a relay access request message to a new relay node (i.e. relay UE 2);

here, the relay access request message may include: identification information of D2D UE, communication service QoS requirement information of D2D UE, D2D security capability information, D2D security related parameter information, D2D communication group identification information of D2DUE, D2D relay type requested by D2D UE, priority information of D2D UE, priority information of D2D communication group where D2D UE is located, priority information of D2D communication service of D2D UE, and configuration information of D2D communication between D2D UE and relay UE.

The traffic QoS requirement information of the D2D UE may include QCI, ARP, GBR, MBR, and other information.

The configuration information of D2D communication between the D2D UE and the relay UE2 may include D2D communication bearer configuration information, security-related configuration information, and the like.

Step 1304: after receiving the relay access request message, the relay UE2 needs to perform admission control to determine whether the D2D UE is allowed to perform cellular communication through the relay access network of the relay UE 2;

specifically, the relay UE2 may determine whether to allow the D2D UE to access according to its own relay capability, transceiving capability, the number of D2D UEs that have accessed, priority information, traffic QoS requirements of the D2D UEs, and other information.

Step 1305: when the relay UE2 determines that the D2D UE is allowed to access, the relay UE2 sends a relay access response message to the D2D UE;

here, the relay access response message may include: identification information of the D2D UE, configuration information of D2D communication between the D2D UE and the relay UE 2.

Among them, the configuration information of D2D communication between the D2D UE and the relay UE2 may include D2D communication bearer configuration information, security-related configuration information, etc.

If the relay UE2 does not allow the D2D UE access, then a reject message is replied to the D2D UE and the D2D UE may select other candidate relay UEs.

Step 1306: the D2D UE sends a relay connection release message to the original relay UE (namely, the relay UE1) after receiving the relay access response message; accordingly, the relay UE1 releases the relay UE1 related context information upon receiving the relay connection release message.

Here, the relay connection release message may include: release indication, identification information of D2D UE, release reason.

In practice, the relay UE1 may also determine whether to release its connection with the D2DUE based on a self-maintained timer. Specifically, the relay UE1 starts/restarts the timer each time it receives a D2D communication packet sent by the D2D UE, releases its connection with the D2D UE when the timer expires, and deletes the D2D UE-related context.

In practical application, the steps are optional.

Example twelve

To implement the method of the embodiment of the present invention, the embodiment provides a D2D UE, which is a first D2D UE, and as shown in fig. 14, the UE includes: a receiving module 141 and a communication module 142; wherein,

the receiving module 141 is configured to receive the D2D relay node replacement instruction information sent by the control node;

the communication module 142 is configured to perform communication through a new D2D relay node according to the D2D relay node replacement indication information.

The communication module 142 is specifically configured to: accessing a cellular network for cellular communication through the new D2D relay node; alternatively, D2D communication is conducted with a second D2D UE through the new D2D relay node.

Wherein the communication module is further configured to transmit, by the new D2D relay node, D2D relay node update information to a second D2D UE before D2D communication with the second D2D UE through the new D2D relay node; the D2D relay node update information is used for the second D2D UE to update self-maintained relay node information;

In practice, after the second D2D UE receives the D2D relay node update information, it replies D2D relay node update confirmation information to the first D2D UE through the new D2D relay node. In other words, the receiving module 141 is further configured to receive the D2D relay node update confirmation information replied by the second D2D UE through the new D2D relay node.

The UE may further include: a sending module, configured to send D2D relay node-related information to the control node; the D2D relay node related information is used by the control node to determine the new D2D relay node.

The D2D relay node related information may include at least one of:

The receiving module 141 is further configured to receive configuration information related to discovery or measurement of a D2D relay node sent by a control node before sending D2D relay node related information to the control node;

The UE may also include a discovery module; wherein,

The sending module is further configured to reply a D2D relay node replacement confirmation message to the control node after receiving the D2D relay node replacement indication information.

In practical application, the receiving module 141, the communication module 142, the sending module, and the discovery module may be implemented by a Central Processing Unit (CPU), a Microprocessor (MCU), a Digital Signal Processor (DSP), or a Programmable logic Array (FPGA) in the first D2D UE in combination with a transceiver.

To implement the method according to the embodiment of the present invention, this embodiment further provides a control node, as shown in fig. 15, where the control node includes: a storage unit 151 and a transmission unit 152; wherein,

the storage unit 151 is configured to store D2D relay node replacement instruction information;

the transmitting unit 152 is configured to transmit the D2D relay node replacement indication information to the first D2D UE, so that the first D2D UE communicates through a new D2D relay node according to the D2D relay node replacement indication information.

The control node may further include: a determining unit, configured to determine the new D2D relay node according to the obtained D2D relay node-related information; and/or determine that the first D2D UE is capable of relaying D2D communications through the new D2D relay node.

The control node may further include: a receiving unit, configured to receive the D2D relay node related information sent by the first D2D UE before determining the new D2D relay node.

The transmitting unit 151, further configured to transmit discovery or measurement related configuration information of a D2D relay node to the first D2D UE before receiving the D2D relay node related information transmitted by the first D2D UE; the configuration information is for the first D2D UE to determine the D2D relay node-related information.

In practical applications, the sending unit 151 may send the discovery or measurement related configuration information of the D2D relay node to the first D2D UE through a Uu interface system message, an RRC dedicated signaling, or a PC5 interface.

The sending unit 151, further configured to send a D2D relay node discovery trigger threshold value to the first D2D UE before receiving the D2D relay node related information sent by the first D2D UE; the D2D relay node discovery trigger threshold is a measurement threshold of the first D2D UE for the accessed original D2D relay node; the D2D relay node discovery trigger threshold value is for the first D2D UE to turn on D2D relay node discovery.

The determining that the first D2D UE can perform relay D2D communication through the new D2D relay node may specifically include:

the determining unit determines, by interacting with a new D2D relay node, that the first D2D UE may relay D2D communications through the new D2D relay node; alternatively, after the determining unit determines that the first D2D UE can perform relay D2D communication through the new D2D relay node through interaction with a central control node and the new D2D relay node.

Wherein the transmitting unit 151 is further configured to transmit D2D relay node update information to the second D2D UE; the D2D relay node update information is used for the second D2D UE to update self-maintained relay node information.

the determining unit sends a relay access request to the new D2D relay node;

the determining unit receives a relay access response replied by the new D2D relay node when itself determines that the first D2D UE is allowed to conduct D2D communications through the relay of the new D2D relay node.

After interacting with the central control node and the new D2D relay node, determining that the first D2D UE can perform relay D2D communication through the new D2D relay node specifically includes:

the determining unit sends a relay access request to the central control node;

the determining unit receives a relay access response sent by the central control node; the relay access response sent by the central control node is the relay access response received by the central control node; the relay access response received by the central control node is the relay access response sent by the central control node and received by the new D2D relay node, and the relay access response replied to the central control node when the first D2D UE is allowed to carry out D2D communication through the relay of the new D2D relay node is determined.

Wherein, the relay access request includes at least one of the following:

In practical application, the relay access response may include: the new D2D relay node allocating an IP address for the first D2D UE.

The relay access response includes at least one of:

The D2D relay type may be classified as: UE to UE relay, UE to network relay.

The receiving unit is further configured to receive a D2D relay node change confirmation message replied by the first D2D UE after sending the D2D relay node change indication information.

In practical applications, the storage unit 151 may be implemented by a memory in the control node, and the sending unit 152, the receiving unit, and the determining unit may be implemented by a CPU, an MCU, a DSP, or an FPGA in the control node in combination with a transceiver.

To implement the method according to the embodiment of the present invention, the embodiment provides a system for replacing a relay node, as shown in fig. 16, where the system includes: a control node 161, a first D2D UE162, and a new D2D relay node 163; wherein,

the control node 161 for transmitting D2D relay node replacement indication information to the first D2D UE 162;

the first D2D UE162, configured to receive D2D relay node replacement indication information sent by the control node 161; and communicates through the new D2D relay node 163 according to the D2D relay node replacement indication information.

Here, the control node 161 may be: a base station, a D2D relay node, a ProSe function, a ProSe application server, or a network element performing D2D relay node management.

The D2D relay node replacement indication information includes at least one of: identification information of the first D2D UE162, new D2D relay node 163 identification information, identification information of the second D2D UE, configuration information of D2D communications between the D2D UE and D2D relay node, a relay status indication, a relay suspension indication, a relay connection release indication, an IP address allocated by the new D2D relay node for the first D2D UE; wherein the second D2D UE is a target D2D UE of the first D2D UE 162.

The control node 161 is further configured to determine the new D2D relay node according to the acquired D2D relay node-related information before sending the D2D relay node replacement indication information to the first D2D UE 162; and/or determine that the first D2D UE is capable of relaying D2D communications through the new D2D relay node.

The control node 161 is further configured to receive the D2D relay node related information sent by the first D2D UE162 before determining the new D2D relay node.

The D2D relay node related information may be a D2D relay node discovery result or measurement information, and specifically may include at least one of the following: D2D relay node information detected by the first D2D UE162, measurement result information of the first D2D UE162 on the received discovery message of D2D relay node; the D2D relay node related information may further include at least one of: geographical location information of the first D2D UE162, identification information of the first D2D UE162, communication service QoS requirement information of the first D2D UE162, D2D security capability information of the first D2D UE162, D2D security-related parameter information of the first D2D UE162, D2D communication group identification information of the first D2D UE162, a D2D relay type requested by the first D2D UE162, identification information of the second D2D UE, priority information of the first D2D UE162, priority information of a D2D communication group where the first D2D UE162 is located, and priority information of D2D communication service of the first D2D UE 162.

Wherein the D2D relay node information detected by the first D2D UE162 may be obtained from the D2D relay discovery message received by the first D2D UE.

The control node 161 is further configured to send discovery or measurement related configuration information of a D2D relay node to the first D2D UE162 before receiving the D2D relay node related information sent by the first D2D UE;

the first D2D UE162 to further determine the D2D relay node related information according to the configuration information.

In practical applications, the control node 161 may send the discovery or measurement related configuration information of the D2D relay node to the first D2D UE162 through a Uu interface system message, an RRC dedicated signaling, or a PC5 interface.

In practical application, the control node 161 is further configured to send a D2D relay node discovery trigger threshold value to the first D2D UE before receiving the D2D relay node related information sent by the first D2D UE; the D2D relay node discovery trigger threshold is a measurement threshold of the first D2D UE for the accessed original D2D relay node;

the first D2D UE162 is further configured to turn on D2D relay node discovery when the measurement value of the original D2D relay node is less than the D2D relay node discovery trigger threshold value.

The control node 161, in particular, configured to determine, by interacting with a new D2D relay node, that the first D2D UE is capable of relaying D2D communications through the new D2D relay node; or,

the system may further comprise: a central control node; wherein,

the control node 161 is specifically configured to determine that the first D2D UE may perform relay D2D communication through the new D2D relay node after interacting with the central control node and the new D2D relay node.

the control node 161 sending a relay access request to the new D2D relay node;

After the control node 161 interacts with the central control node and the new D2D relay node, determining that the first D2D UE can perform relay D2D communication through the new D2D relay node specifically includes:

the control node 161 sends a relay access request to the central control node;

the central control node sends a relay access request to a new D2D relay node;

the new D2D relay node 163 replying to the central control node with a relay access response when determining itself to allow the first D2D UE to communicate D2D through the relay of the new D2D relay node;

and after receiving the relay access response, the central control node replies the relay access response to the control node 161.

Wherein, the relay access request includes at least one of the following:

identification information of the first D2D UE162, identification or identification list information of the second D2D UE, communication service QoS requirement information of the first D2D UE162, D2D security capability information, D2D security related parameter information, D2D communication group identification information of the first D2D UE162, a D2D relay type requested by the first D2D UE162, priority information of the first D2D UE162, priority information of a D2D communication group in which the first D2D UE162 is located, priority information of D2D communication service of the first D2D UE162, and configuration information of D2D communication between the first D2D UE162 and the D2D relay node.

Wherein the configuration information of the D2D communication includes: bearer configuration information, security related configuration information, and the like of the D2D communication between the first D2D UE162 and the D2D relay node.

The relay access response includes at least one of:

identification information of the first D2D UE162, identification (list) information of a target D2D UE of the D2D UE reachable through the new D2D relay node, configuration information of D2D communication between the first D2D UE162 and the new D2D relay node.

The D2D relay type may be classified as: UE to UE relay, UE to network relay.

The first D2D UE162 is further configured to reply a D2D relay node change confirm message to the control node 161 after receiving the D2D relay node change indication information;

accordingly, the control node 161 is further configured to receive the D2D relay node replacement confirmation message.

The first D2D UE is specifically configured to: accessing a cellular network for cellular communication through the new D2D relay node; or,

the system may further comprise: a second D2D UE; wherein,

the D2D UE162 is specifically configured to: D2D communications with a second D2D UE through the new D2D relay node; the second D2D UE is a target D2D UE of the first D2D UE 162.

Wherein the first D2D UE162 is further configured to send D2D relay node update information to the second D2D UE via the new D2D relay node 163 before D2D communication is conducted with the second D2D UE via the new D2D relay node 163;

The control node 161 further configured to send D2D relay node update information to the second D2D UE;

or,

the new D2D relay node 163 to send D2D relay node update information to the second D2D UE;

Wherein the D2D relay node update information may include at least one of: identification information of the first D2DUE 162, identification information of the second D2D UE, identification information of the new D2D relay node 163, configuration information of D2D communication between the second D2D UE and the new D2D relay node 163.

The second D2D UE, further configured to reply with a D2D relay node update confirm message to the new D2D relay node 163 after receiving the D2D relay node update message.

Wherein the D2D relay node update confirmation information may include: identification information of the first D2D UE162, identification information of the second D2D UE, identification information of the new D2D relay node 163.

The system may further comprise: an old D2D relay node for releasing the connection between itself and the first D2D UE after the first D2D UE162 communicates through the new D2D relay node 163;

specifically, the original D2D relay node releases the connection between itself and the first D2D UE162 after the timeout of its own maintained timer; or, after receiving the relay connection release indication information sent by the first D2DUE 132, the original D2D relay node releases the connection between itself and the D2 DUE; or, the original D2D relay node releases the connection between itself and the first D2D UE after receiving the relay connection release indication information sent by the control node 161.

Wherein the original D2D relay node starts or restarts the timer upon receiving the D2D communication data transmitted by the first D2D UE162 or transmitting the D2D communication data to the first D2D UE 162.

The relay connection release indication information includes at least one of:

The control node 161 is further configured to receive, before sending the relay connection release indication information to the original D2D relay node, the D2D relay node replacement confirmation information sent by the first D2D UE 162; or, receiving the D2D UE access completion indication information sent by the new D2D relay node 163.

In the solution provided by the embodiment of the present invention, the control node 161 sends D2D relay node replacement indication information to the first D2D UE 162; the first D2D UE162 receiving D2D relay node replacement indication information transmitted by a control node; the first D2D UE162 performs communication through the new D2D relay node 163 according to the D2D relay node replacement indication information, so as to solve the problem of D2DUE replacement of the relay node in the D2D communication relay transmission mode, and thus, the D2D UE can timely access the appropriate relay node, thereby ensuring smooth D2D communication.

As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of a hardware embodiment, a software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, optical storage, and the like) having computer-usable program code embodied therein.

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention.

Claims

1. A method of replacing a relay node, the method comprising:

2. The method of claim 1, wherein the communicating through the new D2D relay node comprises:

3. The method of claim 2, wherein prior to the first D2D UE communicating D2D with a second D2D UE through the new D2D relay node, the method further comprises:

4. The method of claim 3, wherein the D2D relay node update information comprises at least one of: identification information of the first D2D UE, identification information of the second D2D UE, identification information of the new D2D relay node, configuration information of D2D communication between the second D2D UE and the new D2D relay node.

5. The method according to claim 1, wherein before receiving the D2D relay node replacement indication information sent by the control node, the method further comprises:

6. The method of claim 5, wherein the D2D relay node related information comprises at least one of:

7. The method of claim 5, wherein before sending the D2D relay node related information to the control node, the method further comprises:

8. The method of claim 7, wherein the discovery or measurement related configuration information of the D2D relay node comprises:

9. The method of claim 5, wherein before sending the D2D relay node related information to the control node, the method further comprises:

10. The method according to claim 1, wherein after receiving the D2D relay node replacement indication information, the method further comprises:

11. The method of claim 3, further comprising:

12. The method of claim 11, wherein the D2D relay node update confirmation information comprises: identification information of the first D2D UE, identification information of the second D2D UE, identification information of the new D2D relay node.

13. The method of claim 1, wherein the D2D relay node replacement indication information comprises at least one of: identification information of the first D2D UE, new D2D relay node identification information, identification information of the second D2D UE, configuration information of D2D communication between the D2D UE and a D2D relay node, a relay status indication, a relay suspension indication, a relay connection release indication, an IP address allocated by the new D2D relay node for the first D2D UE; wherein the second D2DUE is a target D2D UE of the first D2D UE.

14. A method of replacing a relay node, the method comprising:

15. The method of claim 14, wherein the control node is a base station, a D2D relay node, a proximity services function entity, ProSe function, a proximity services ProSe application server, or a network element performing D2D relay node management.

16. The method of claim 14, wherein the D2D relay node replacement indication information comprises at least one of: identification information of the first D2D UE, new D2D relay node identification information, identification information of the second D2D UE, configuration information of D2D communication between the D2D UE and a D2D relay node, a relay status indication, a relay suspension indication, a relay connection release indication, an IP address allocated by the new D2D relay node for the first D2D UE; wherein the second D2D UE is a target D2D UE of the first D2D UE.

17. The method of claim 14, wherein prior to the sending the D2D relay node replacement indication information to the first D2D UE, the method further comprises:

18. The method of claim 17, wherein prior to said determining the new D2D relay node, the method further comprises:

19. The method of claim 17, wherein the D2D relay node related information comprises at least one of:

20. The method of claim 18, wherein prior to the receiving the D2D relay node-related information sent by the first D2D UE, the method further comprises:

21. The method of claim 20, wherein the controlling node sends discovery or measurement related configuration information of D2D relay nodes to the first D2D UE over a Uu interface system message, or RRC dedicated signaling, or a PC5 interface.

22. The method of claim 20, wherein the configuration information related to discovery or measurement of the D2D relay node comprises:

23. The method of claim 18, wherein prior to the receiving the D2D relay node-related information sent by the first D2D UE, the method further comprises:

24. The method of claim 17, wherein the control node determining that the first D2D UE is capable of relaying D2D communications through the new D2D relay node comprises:

25. The method of claim 24, wherein the determining that the first D2D UE may relay D2D communications through a new D2D relay node after interacting with the new D2D relay node comprises:

the control node sends a relay access request to the new D2D relay node;

26. The method of claim 25, wherein the relay access response comprises: the new D2D relay node allocates an IP address for the D2D UE.

27. The method of claim 24, wherein the determining, by the control node through interaction with a central control node and the new D2D relay node, that the first D2D UE may relay D2D communications through the new D2D relay node comprises:

the control node sends a relay access request to the central control node;

28. The method of claim 27, wherein the relay access response comprises: the new D2D relay node allocating an IP address for the first D2D UE.

29. The method according to claim 26 or 27, wherein the relay access request comprises at least one of:

30. The method of claim 29, wherein the configuration information communicated by the D2D comprises: bearer configuration information for D2D communication between the first D2D UE and the D2D relay node, and security related configuration information.

31. The method of claim 27, wherein the D2D relay type is UE-to-UE relay or UE-to-network relay.

32. The method of claim 27, wherein the relay access response comprises at least one of:

33. The method of claim 14, wherein after sending the D2D relay node replacement indication information, the method further comprises:

receiving a D2D relay node change confirm message replied by the first D2D UE.

34. The method of claim 17, further comprising:

35. The method of claim 34, wherein the D2D relay node update information comprises at least one of: identification information of the first D2D UE, identification information of the second D2D UE, identification information of the new D2D relay node, configuration information of D2D communication between the second D2D UE and the new D2D relay node.

36. A D2D UE, wherein the UE comprises: a receiving module and a communication module; wherein,

37. The UE of claim 36, wherein the communication module is specifically configured to: accessing a cellular network for cellular communication through the new D2D relay node;

38. The UE of claim 37, wherein the communication module is further configured to send D2D relay node update information to a second D2D UE via the new D2D relay node prior to D2D communication with the second D2D UE via the new D2D relay node; the D2D relay node update information is used for the second D2D UE to update self-maintained relay node information.

39. The UE of claim 36, wherein the UE further comprises: a sending module, configured to send D2D relay node-related information to the control node; the D2D relay node related information is used by the control node to determine the new D2D relay node.

40. The UE of claim 38, wherein the receiving module is further configured to receive discovery or measurement related configuration information for a D2D relay node sent by a control node before sending D2D relay node related information to the control node;

41. The UE of claim 38, further comprising a discovery module; wherein,

42. The UE of claim 36, wherein the sending module is further configured to reply to the control node with a D2D relay node change confirm message after receiving the D2D relay node change indication information.

43. The UE of claim 34, wherein the receiving module is further configured to receive a D2D relay node update confirmation replied by the second D2D UE through the new D2D relay node.

44. A control node, characterized in that the control node comprises: a storage unit and a transmission unit; wherein,

45. The control node according to claim 44, characterized in that it further comprises: a determining unit, configured to determine the new D2D relay node according to the obtained D2D relay node-related information; and/or determine that the first D2D UE is capable of relaying D2D communications through the new D2D relay node.

46. The control node according to claim 45, characterized in that it further comprises: a receiving unit, configured to receive the D2D relay node related information sent by the first D2D UE before determining the new D2D relay node.

47. The controlling node according to claim 45, wherein said transmitting unit is further configured to transmit discovery or measurement related configuration information of D2D relay nodes to the first D2DUE before receiving the D2D relay node related information transmitted by the first D2D UE; the configuration information is for the first D2D UE to determine the D2D relay node-related information.

48. The controlling node of claim 46, wherein the sending unit is further configured to send a D2D relay node discovery trigger threshold value to the first D2DUE before receiving the D2D relay node related information sent by the first D2D UE; the D2D relay node discovery trigger threshold is a measurement threshold of the first D2D UE for the accessed original D2D relay node; the D2D relay node discovery trigger threshold value is for the first D2D UE to turn on D2D relay node discovery.

49. The controlling node of claim 44, wherein the receiving unit is further configured to receive a D2D relay node change confirmation message replied by the first D2D UE after sending the D2D relay node change indication information.

50. The control node according to claim 45, wherein said transmitting unit is further configured to transmit D2D relay node update information to the second D2D UE; the D2D relay node update information is used for the second D2D UE to update self-maintained relay node information; wherein the second D2DUE is a target D2D UE of the first D2D UE.

51. A system for replacing a relay node, the system comprising: a control node, a first D2D UE, and a new D2D relay node; wherein,

52. The system according to claim 51, wherein said control node is further configured to determine said new D2D relay node based on the obtained D2D relay node related information, before sending D2D relay node change indication information to said first D2D UE; and/or determine that the first D2D UE is capable of relaying D2D communications through the new D2D relay node.

53. The system of claim 52, wherein the control node is further configured to receive D2D relay node related information sent by the first D2D UE before determining the new D2D relay node.

54. The system according to claim 53, wherein said control node is further configured to send D2D relay node discovery or measurement related configuration information to said first D2D UE before receiving D2D relay node related information sent by said first D2D UE;

55. The system of claim 53, wherein the control node is further configured to send a D2D relay node discovery trigger threshold to the first D2D UE before receiving the D2D relay node related information sent by the first D2D UE; the D2D relay node discovery trigger threshold is a measurement threshold of the first D2D UE for the accessed original D2D relay node;

56. The system according to claim 52, wherein said control node, in particular configured to determine, by interacting with a new D2D relay node, that said first D2D UE is capable of relaying D2D communications via said new D2D relay node; or,

the system further comprises: a central control node; wherein,

57. The system according to claim 56, wherein said central control node is hosted by a D2D relay node, said central control node being adapted to obtain relay related information for its own nearby D2D relay node.

58. The system according to claim 57, wherein said central control node is specifically configured to: the relay related information of the relay node nearby the relay node is obtained by monitoring the relay node discovery message or the broadcast information, or the corresponding relay related information is obtained from the relay node.

59. The system according to claim 51, wherein said first D2D UE is further configured to reply with a D2D Relay node Change acknowledgement message to the control node after receiving the D2D Relay node Change indication information;

60. The system according to claim 51, wherein the first D2D UE is specifically configured to: accessing a cellular network for cellular communication through the new D2D relay node; or,

the system further comprises: a second D2D UE; wherein,

the D2D UE is specifically configured to:

61. The system of claim 58, wherein the first D2D UE is further configured to send D2D relay node update information to a second D2D UE via the new D2D relay node prior to D2D communications with the second D2D UE via the new D2D relay node;

62. The system of claim 56, further comprising: a second D2D UE; the second D2D UE is a target D2D UE of the first D2D UE; wherein,

or,

63. The system according to claim 60 or 61, wherein said second D2D UE is further configured to reply with a D2D relay node update confirmation message to the new D2D relay node after receiving the D2D relay node update information.

64. The system of claim 51, further comprising an old D2D relay node configured to release the connection with the first D2D UE after the first D2D UE communicates through a new D2D relay node.

65. The system according to claim 64, wherein the old D2D relay node is specifically configured to: releasing a connection between itself and the first D2D UE1 after a self-maintained timer expires; or after receiving the relay connection release indication information sent by the first D2D UE, releasing the connection between the first D2D UE and the D2D UE; or, the original D2D relay node releases the connection between itself and the first D2D UE after receiving the relay connection release indication information sent by the control node.

66. The system of claim 65, wherein the original D2D relay node is further configured to start or restart the timer upon receiving D2D communication data sent by the first D2D UE or sending D2D communication data to the first D2DUE 162.

67. The system according to claim 65, wherein said relay connection release indication information comprises at least one of:

68. The system according to claim 65, wherein said control node is further configured to receive D2D Relay node Change acknowledgement information sent by said first D2DUE, before sending Relay connection Release indication information to said original D2D Relay node; or receiving the D2D UE access completion indication information sent by the new D2D relay node.