Method and apparatus for relay connection between nodes

Abstract

Techniques for relay connection between nodes are provided. For example, a method for relay connection between nodes includes transmitting a communication request message from a source node to a relay node for establishing a connection to a target node via the relay node; and receiving, at the source node, a communication rejection message from the relay node indicating a rejection of establishing the connection by the target node.

Description

Technical Field

[0001] The present disclosure relates generally to wireless communication systems, and more particularly to wireless communication systems that allow connections between nodes via relay nodes. More particularly, the present disclosure provides methods and apparatus for relay connections between nodes. Background Art

[0002] Wireless communication systems are constantly evolving. Higher data rates and higher quality of service are required. Reliability requirements are increasing, and methods and means to ensure reliable connections and data throughput while minimizing transmission delays are also under development.

[0003] Standardization bodies such as the 3rd Generation Partnership Project (3GPP) are studying potential solutions for efficient operation of wireless communications in New Radio (NR) networks. The next-generation mobile wireless communication system, 5G / NR, will support a diverse set of use cases and deployment scenarios. In addition to typical mobile broadband use cases, NR is being developed to support machine-type communications (MTC), ultra-reliable low-latency communications (URLCC), sidelink device-to-device (D2D), and other use cases. Summary of the Invention

[0004] The present disclosure aims to provide a mechanism that helps improve relay connections between nodes in a network, thereby improving direct communication services. A method and apparatus for relay connections between nodes are provided to improve direct communication services.

[0005] According to a first aspect of the present disclosure, a method for relaying a connection between nodes is provided. The method comprises: sending a communication request message from a source node to a relay node for establishing a connection to a target node via the relay node; and receiving, at the source node, a communication rejection message from the relay node indicating rejection of the connection establishment by the target node.

[0006] In some examples of the first aspect, the method further includes, in response to receiving the communication rejection message, retrying to establish a connection to the target node by sending another communication request message from the source node to the relay node for establishing a connection to the target node via the relay node.

[0007] In some examples of the first aspect, the method further includes: in response to receiving the communication rejection message, starting a timer; and in response to expiration of the timer, sending another communication request message.

[0008] In some examples of the first aspect, the method further includes: in response to receiving the communication rejection message, performing a relay reselection process to select another relay node; and sending a communication request message from the source node to the other relay node for establishing a connection to the target node via the other relay node.

[0009] In some examples of the first aspect, the method further includes: in response to receiving the communication rejection message, determining whether the rejection by the target node is permanent; and in response to determining that the rejection is permanent, performing a discovery process to discover another target node to establish a connection with via the relay node or another relay node.

[0010] In some examples of the first aspect, the method also includes: sending a communication request message from the source node to the relay node for modifying an existing connection to the relay node to establish a connection to the target node; and receiving a communication rejection message from the relay node at the source node indicating a rejection of modifying the existing connection due to a rejection of establishing the connection by the target node.

[0011] In some examples of the first aspect, the method also includes: sending a communication request message from the source node to the relay node for establishing a connection to the target node by modifying the existing connection between the relay node and the target node; and receiving a communication rejection message from the relay node at the source node indicating a rejection of establishing a connection between the source node and the relay node due to a rejection of modifying the existing connection between the relay node and the target node.

[0012] In some examples of the first aspect, the communication rejection message indicating rejection of connection modification includes identification information indicating a source node and / or identification information indicating a target node.

[0013] In some examples of the first aspect, the method further includes: deriving the target node that caused the rejection from the plurality of target nodes that the source node is attempting to connect to based on identification information indicating the target node.

[0014] In some examples of the first aspect, the communication request message for modifying the connection includes a PROSE DIRECT LINK MODIFICATION REQUEST message, and / or the communication rejection message indicating rejection of modifying the connection includes a PROSE DIRECT LINK MODIFICATION REJECT message.

[0015] In some examples of the first aspect, the communication rejection message includes one or more reason values ​​indicating that the rejection is due to rejection by the target node.

[0016] In some examples of the first aspect, the one or more cause values ​​are included in an existing information element in the communication rejection message for signaling a cause value to the relay node.

[0017] In some examples of the first aspect, the communication rejection message includes an additional information element for signaling a cause value to the target node.

[0018] In some examples of the first aspect, the communication request message for establishing the connection includes a PROSE DIRECT LINK ESTABLISHMENT REQUEST message, and / or the communication rejection message indicating rejection of establishing the connection includes a PROSE DIRECT LINK ESTABLISHMENT REJECT message.

[0019] In some examples of the first aspect, the communication rejection message indicates a rejection by the one or more second relay nodes via which the source node is to be connected to the target node.

[0020] In some examples of the first aspect, the communication rejection message includes one or more cause values ​​indicating that the rejection is due to rejection by a second relay node of the one or more second relay nodes.

[0021] In some examples of the first aspect, the one or more cause values ​​are included in an existing information element in the communication rejection message for signaling a cause value to the relay node.

[0022] In some examples of the first aspect, the communication rejection message includes an additional information element for signaling a cause value to the second relay node.

[0023] In some examples of the first aspect, the source node includes a user equipment (UE).

[0024] According to a second aspect of the present disclosure, a method for relaying a connection between nodes is provided. The method comprises: sending, from a source node to a relay node, a communication request message for modifying an existing connection to the relay node so as to establish a connection to a target node via the relay node; and receiving, at the source node, a communication rejection message from the relay node indicating rejection of modifying the existing connection due to rejection of establishing the connection by the target node.

[0025] In some examples, the method according to the second aspect includes one or more examples of the method according to the first aspect as described above.

[0026] According to a third aspect of the present disclosure, a method for relaying a connection between nodes is provided. The method includes: sending, from a source node to a relay node, a communication request message for establishing a connection to a target node via the relay node by modifying an existing connection between the relay node and the target node; and receiving, at the source node, from the relay node, a communication rejection message indicating rejection of establishing a connection between the source node and the relay node due to rejection of modifying the existing connection between the relay node and the target node.

[0027] In some examples, the method according to the third aspect includes one or more examples of the method according to the first aspect as described above.

[0028] According to a fourth aspect of the present disclosure, a method for relaying a connection between nodes is provided. The method comprises: receiving, at a relay node, a communication request message from a source node for establishing a connection to a target node via the relay node; establishing a connection to the target node; and, in response to receiving a rejection of the connection establishment by the target node, sending, from the relay node to the source node, a communication rejection message indicating the rejection of the connection establishment by the target node.

[0029] In some examples of the third aspect, the method also includes: receiving, at the relay node, a communication request message from the source node for modifying an existing connection to the relay node to establish a connection to the target node; and in response to receiving a rejection of establishing the connection by the target node, sending a communication rejection message from the relay node to the source node indicating a rejection of modifying the existing connection due to the rejection of establishing the connection by the target node.

[0030] In some examples of the third aspect, the method also includes: receiving, at the relay node, a communication request message from the source node for establishing a connection to the target node by modifying the existing connection between the relay node and the target node; and sending, from the relay node to the source node, a communication rejection message indicating a rejection of establishing a connection between the source node and the relay node due to a rejection of modifying the existing connection between the relay node and the target node.

[0031] In some examples of the third aspect, the communication rejection message indicating rejection of modifying the connection includes identification information indicating a source node and / or identification information indicating a target node.

[0032] In some examples of the third aspect, the method further includes: deriving the source node that caused the rejection from a plurality of source nodes to which the target node is connected based on identification information indicating the source node.

[0033] In some examples of the third aspect, the communication request message for modifying the connection includes a PROSE DIRECT LINK MODIFICATION REQUEST message, and / or the communication rejection message indicating rejection of modifying the connection includes a PROSE DIRECT LINK MODIFICATION REJECT message.

[0034] In some examples of the third aspect, the communication rejection message includes one or more reason values ​​indicating that the rejection is due to rejection by the target node.

[0035] In some examples of the third aspect, the one or more cause values ​​are included in an existing information element in the communication rejection message for signaling a cause value to the relay node.

[0036] In some examples of the third aspect, the communication rejection message includes an additional information element for signaling a cause value to the target node.

[0037] In some examples of the third aspect, the communication request message for establishing the connection includes a PROSE DIRECT LINK ESTABLISHMENT REQUEST message, and / or the communication rejection message indicating rejection of establishing the connection includes a PROSE DIRECT LINK ESTABLISHMENT REJECT message.

[0038] In some examples of the third aspect, the communication rejection message indicates a rejection by the one or more second relay nodes via which the source node is to be connected to the target node.

[0039] In some examples of the third aspect, the communication rejection message includes one or more reason values ​​indicating that the rejection is due to rejection by a second relay node of the one or more second relay nodes.

[0040] In some examples of the third aspect, the one or more cause values ​​are included in an existing information element in the communication rejection message for signaling a cause value to the relay node.

[0041] In some examples of the third aspect, the communication rejection message includes an additional information element for signaling a cause value to the second relay node.

[0042] In some examples of the third aspect, the method further includes: in response to receiving a rejection by one or more second relay nodes, performing a relay reselection process to select another second relay node; and establishing a connection to the target node via the another second relay node.

[0043] In some examples of the third aspect, the relay node includes a user equipment (UE).

[0044] According to a fifth aspect of the present disclosure, a method for relaying a connection between nodes is provided. The method comprises: receiving, at a relay node, a communication request message from a source node for modifying an existing connection to the relay node to establish a connection to a target node via the relay node; establishing a connection to the target node; and, in response to receiving a rejection of the connection establishment by the target node, sending, from the relay node to the source node, a communication rejection message indicating a rejection of modifying the existing connection due to the rejection of the connection establishment by the target node.

[0045] In some examples, the method according to the fifth aspect includes one or more examples of the method according to the fourth aspect as described above.

[0046] According to a sixth aspect of the present disclosure, a method for relaying a connection between nodes is provided. The method includes: receiving, at a relay node, a communication request message from a source node for establishing a connection to a target node via the relay node by modifying an existing connection between the relay node and the target node; establishing a connection to the target node; and, in response to receiving a rejection of the connection establishment by the target node, sending, from the relay node to the source node, a communication rejection message indicating a rejection of establishing a connection between the source node and the relay node due to the rejection of modifying the existing connection between the relay node and the target node.

[0047] In some examples, the method according to the sixth aspect includes one or more examples of the method according to the fourth aspect as described above.

[0048] According to a seventh aspect of the present disclosure, a method for relaying a connection between nodes is provided. The method includes: receiving, at a first relay node, from a second relay node, a communication request message for establishing a connection from a source node to a destination node via the first relay node; establishing a connection to the destination node; and, in response to receiving a rejection of the connection establishment by the destination node, sending, from the first relay node to the second relay node, a communication rejection message indicating the rejection of the connection establishment by the destination node. Optionally, in some examples, the connection to the destination node may be established via one or more additional relay nodes.

[0049] In some examples, the method according to the seventh aspect includes one or more examples of the method according to the fourth aspect as described above.

[0050] According to an eighth aspect of the present disclosure, a method for relaying a connection between nodes is provided. The method includes: receiving, at a first relay node, from a second relay node, a communication request message for modifying an existing connection to the first relay node to establish a connection from a source node to a destination node via the first relay node; establishing a connection to the destination node; and, in response to receiving a rejection of the destination node for establishing the connection, sending, from the second relay node to the first relay node, a communication rejection message indicating a rejection of modifying the existing connection due to the rejection of the destination node for establishing the connection. Optionally, in some examples, the connection to the destination node may be established via one or more additional relay nodes.

[0051] In some examples, the method according to the eighth aspect includes one or more examples of the method according to the fourth aspect as described above.

[0052] According to a ninth aspect of the present disclosure, a method for relaying connections between nodes is provided. The method comprises: receiving, at a first relay node, from a second relay node, a communication request message for establishing a connection from a source node to a target node via the first relay node by modifying an existing connection between the first relay node and the target node; modifying the existing connection to the target node; and in response to receiving a rejection of modifying the existing connection by the target node, sending, from the first relay node to the second relay node, a communication rejection message indicating a rejection of establishing a connection from the source node to the target node due to a rejection of modifying the existing connection between the first relay node and the target node. Optionally, in some examples, the (existing) connection to the target node can be established via one or more additional relay nodes.

[0053] In some examples, the method according to the ninth aspect includes one or more examples of the method according to the fourth aspect as described above.

[0054] According to a tenth aspect of the present disclosure, a source node (e.g., a source user equipment or user equipment (UE)) or an apparatus in such a source node is provided. The source node or apparatus according to the tenth aspect includes at least one processor and at least one memory including computer program code. The computer program code, when executed by the at least one processor, causes the source node or apparatus to: send a communication request message to a relay node for establishing a connection to a target node via the relay node; and receive a communication rejection message from the relay node indicating a rejection by the target node of establishing the connection.

[0055] In some examples of the tenth aspect, the computer program code, when executed using the at least one processor, also causes the device or source node to: in response to receiving a communication rejection message, retry establishing a connection to the target node by sending another communication request message to the relay node for establishing a connection to the target node via the relay node.

[0056] In some examples of the tenth aspect, the computer program code, when executed using the at least one processor, further causes the apparatus or source node to: start a timer in response to receiving a communication rejection message; and send another communication request message in response to expiration of the timer.

[0057] In some examples of the tenth aspect, the computer program code, when executed using the at least one processor, further causes the device or source node to: in response to receiving a communication rejection message, perform a relay reselection process to select another relay node; and send a communication request message to the other relay node for establishing a connection to the target node via the other relay node.

[0058] In some examples of the tenth aspect, the computer program code, when executed using the at least one processor, further causes the apparatus or source node to: in response to receiving a communication rejection message, determine whether the rejection by the target node is permanent; and in response to determining that the rejection is permanent, perform a discovery process to discover another target to which a connection is established via the relay node or another relay node.

[0059] In some examples of the tenth aspect, the computer program code, when executed by the at least one processor, further causes the apparatus or source node to: send a communication request message to the relay node for modifying an existing connection to the relay node to establish a connection to the target node; and receive a communication rejection message from the relay node indicating a rejection of modifying the existing connection due to a rejection of establishing the connection by the target node.

[0060] In some examples of the tenth aspect, the computer program code, when executed using the at least one processor, further causes the apparatus or source node to: send a communication request message to the relay node for establishing a connection to the target node by modifying the existing connection between the relay node and the target node; and receive a communication rejection message from the relay node indicating a rejection of establishing a connection between the source node and the relay node due to a rejection of modifying the existing connection between the relay node and the target node.

[0061] In some examples of the tenth aspect, the communication rejection message indicating rejection of modifying the connection includes identification information indicating a source node and / or identification information indicating a target node.

[0062] In some examples of the tenth aspect, the computer program code, when executed using the at least one processor, further causes the apparatus or source node to: derive, based on identification information indicating the target node, a target node that caused the rejection from a plurality of target nodes that the source node is attempting to connect to.

[0063] In some examples of the tenth aspect, the communication request message for modifying the connection includes a PROSE DIRECT LINK MODIFICATION REQUEST message, and / or the communication rejection message indicating rejection of modifying the connection includes a PROSE DIRECT LINK MODIFICATION REJECT message.

[0064] In some examples of the tenth aspect, the communication rejection message includes one or more reason values ​​indicating that the rejection is due to rejection by the target node.

[0065] In some examples of the tenth aspect, the one or more cause values ​​are included in an existing information element in the communication rejection message for signaling a cause value to the relay node.

[0066] In some examples of the tenth aspect, the communication rejection message includes an additional information element for signaling a cause value to the target node.

[0067] In some examples of the tenth aspect, the communication request message for establishing the connection includes a PROSE DIRECT LINK ESTABLISHMENT REQUEST message, and / or the communication rejection message indicating rejection of establishing the connection includes a PROSE DIRECT LINK ESTABLISHMENT REJECT message.

[0068] In some examples of the tenth aspect, the communication rejection message indicates a rejection by the one or more second relay nodes via which the source node is to be connected to the target node.

[0069] In some examples of the tenth aspect, the communication rejection message includes one or more reason values ​​indicating that the rejection is due to rejection by a second relay node of the one or more second relay nodes.

[0070] In some examples of the tenth aspect, the one or more cause values ​​are included in an existing information element in the communication rejection message for signaling a cause value to the relay node.

[0071] In some examples of the tenth aspect, the communication rejection message includes an additional information element for signaling a cause value to the second relay node.

[0072] According to an eleventh aspect of the present disclosure, a source node (e.g., a source user equipment or user equipment (UE)) or an apparatus in such a source node is provided. The source node or apparatus according to the eleventh aspect includes at least one processor and at least one memory including computer program code. The computer program code, when executed by the at least one processor, causes the source node or apparatus to: send a communication request message to a relay node for modifying an existing connection to the relay node to establish a connection to a target node via the relay node; and receive a communication rejection message from the relay node indicating a rejection of modifying the existing connection due to a rejection of establishing the connection by the target node.

[0073] In some examples, the computer program code, when executed using the at least one processor, causes the source node or device according to the eleventh aspect to perform one or more examples of the method according to the first aspect as described above.

[0074] According to a twelfth aspect of the present disclosure, a source node (e.g., a source user device or user equipment (UE)) or an apparatus in such a source node is provided. The source node or apparatus according to the twelfth aspect includes at least one processor and at least one memory including computer program code. The computer program code, when executed by the at least one processor, causes the source node or apparatus to: send a communication request message to a relay node for establishing a connection to a target node via the relay node by modifying an existing connection between the relay node and the target node; and receive a communication rejection message from the relay node indicating a rejection of establishing a connection between the source node and the relay node due to a rejection of modifying the existing connection between the relay node and the target node.

[0075] In some examples, the computer program code, when executed using the at least one processor, causes the source node or device according to the twelfth aspect to perform one or more examples of the method according to the first aspect as described above.

[0076] According to a thirteenth aspect of the present disclosure, a relay node (e.g., a relay user equipment or user equipment (UE)) or an apparatus in such a relay node is provided. The relay node or apparatus according to the thirteenth aspect comprises at least one processor and at least one memory comprising computer program code. The computer program code, when executed by the at least one processor, causes the relay node or apparatus to: receive a communication request message from a source node for establishing a connection to a target node via the relay node; establish a connection to the target node; and, in response to receiving a rejection of the establishment of the connection by the target node, send a communication rejection message to the source node indicating the rejection of the establishment of the connection by the target node.

[0077] In some examples of the thirteenth aspect, the computer program code, when executed using the at least one processor, further causes the device or relay node to: receive a communication request message from a source node for modifying an existing connection to the relay node to establish a connection to a target node; and in response to receiving a rejection of establishing the connection by the target node, send a communication rejection message to the source node indicating a rejection of modifying the existing connection due to the rejection of establishing the connection by the target node.

[0078] In some examples of the thirteenth aspect, the computer program code, when executed using the at least one processor, further causes the device or relay node to: receive a communication request message from a source node for establishing a connection to a target node by modifying an existing connection between the relay node and the target node; and send a communication rejection message to the source node indicating a rejection of establishing a connection between the source node and the relay node due to a rejection of modifying the existing connection between the relay node and the target node.

[0079] In some examples of the thirteenth aspect, the communication rejection message indicating rejection of modifying the connection includes identification information indicating the source node and / or identification information indicating the target node.

[0080] In some examples of the thirteenth aspect, the computer program code, when executed by the at least one processor, further causes the device or relay node to: derive the source node that caused the rejection from the multiple source nodes to which the target node is connected based on identification information indicating the source node.

[0081] In some examples of the thirteenth aspect, the communication request message for modifying the connection includes a PROSE DIRECT LINK MODIFICATION REQUEST message, and / or the communication rejection message indicating rejection of modifying the connection includes a PROSE DIRECT LINK MODIFICATION REJECT message.

[0082] In some examples of the thirteenth aspect, the communication rejection message includes one or more reason values ​​indicating that the rejection is due to rejection by the target node.

[0083] In some examples of the thirteenth aspect, the one or more cause values ​​are included in an existing information element in the communication rejection message for signaling a cause value to the relay node.

[0084] In some examples of the thirteenth aspect, the communication rejection message includes an additional information element for signaling a cause value to the target node.

[0085] In some examples of the thirteenth aspect, the communication request message for establishing the connection includes a PROSE DIRECT LINK ESTABLISHMENT REQUEST message, and / or the communication rejection message indicating rejection of establishing the connection includes a PROSE DIRECT LINK ESTABLISHMENT REJECT message.

[0086] In some examples of the thirteenth aspect, the communication rejection message indicates a rejection by the one or more second relay nodes via which the source node is to be connected to the target node.

[0087] In some examples of the thirteenth aspect, the communication rejection message includes one or more cause values ​​indicating that the rejection is due to rejection by a second relay node of the one or more second relay nodes.

[0088] In some examples of the thirteenth aspect, the one or more cause values ​​are included in an existing information element in the communication rejection message for signaling a cause value to the relay node.

[0089] In some examples of the thirteenth aspect, the communication rejection message includes an additional information element for signaling a cause value to the second relay node.

[0090] In some examples of the thirteenth aspect, the computer program code, when executed using the at least one processor, further causes the device or relay node to: in response to receiving a rejection by one or more second relay nodes, perform a relay reselection process to select another second relay node; and establish a connection to the target node via the another second relay node.

[0091] According to a fourteenth aspect of the present disclosure, a relay node (e.g., a relay user equipment or user equipment (UE)) or an apparatus in such a relay node is provided. The relay node or apparatus according to the fourteenth aspect includes at least one processor and at least one memory including computer program code. The computer program code, when executed by the at least one processor, causes the relay node or apparatus to: receive a communication request message from another relay node for establishing a connection from a source node to a target node via the relay node; establish a connection to the target node; and in response to receiving a rejection of the establishment of the connection by the target node, send a communication rejection message to the other relay node indicating the rejection of the establishment of the connection by the target node. Optionally, in some examples, the connection to the target node may be established via one or more additional relay nodes.

[0092] In some examples, the computer program code, when executed by the at least one processor, causes the relay node or device according to the fourteenth aspect to perform one or more examples of the method according to the fourth aspect as described above.

[0093] According to a fifteenth aspect of the present disclosure, a relay node (e.g., a relay user equipment or user equipment (UE)) or an apparatus in such a relay node is provided. The relay node or apparatus according to the fifteenth aspect includes at least one processor and at least one memory including computer program code. The computer program code, when executed by the at least one processor, causes the relay node or apparatus to: receive a communication request message from another relay node for modifying an existing connection to the relay node to establish a connection from a source node to a target node via the relay node; establish a connection to the target node; and in response to receiving a rejection of establishing the connection by the target node, send a communication rejection message to another relay node indicating a rejection of modifying the existing connection due to the rejection of establishing the connection by the target node. Optionally, in some examples, the connection to the target node may be established via one or more additional relay nodes.

[0094] In some examples, the computer program code, when executed using the at least one processor, causes the relay node or device according to the fifteenth aspect to perform one or more examples of the method according to the fourth aspect as described above.

[0095] According to the sixteenth aspect of the present disclosure, a relay node (e.g., a relay user equipment or user equipment (UE)) or an apparatus in such a relay node is provided. The relay node or apparatus according to the sixteenth aspect includes at least one processor and at least one memory including computer program code. When the computer program code is executed using the at least one processor, the relay node or apparatus causes the relay node or apparatus to: receive from another relay node a communication request message for establishing a connection from a source node to a target node via the relay node by modifying an existing connection between the relay node and the target node; modify the existing connection to the target node; and in response to receiving a rejection of the modification of the existing connection by the target node, send to another relay node a communication rejection message indicating a rejection of establishing a connection from the source node to the target node due to the rejection of modifying the existing connection between the relay node and the target node. Optionally, in some examples, the (existing) connection to the target node can be established via one or more additional relay nodes.

[0096] In some examples, the computer program code, when executed using the at least one processor, causes the relay node or device according to the sixteenth aspect to perform one or more examples of the method according to the fourth aspect as described above.

[0097] According to a seventeenth aspect of the present disclosure, a source node (e.g., a source user equipment or user equipment (UE)) or an apparatus in such a source node is provided. The source node or apparatus according to the seventeenth aspect includes: a component (sending module) for sending a communication request message for establishing a connection to a target node via the relay node to a relay node; and a component (receiving module) for receiving a communication rejection message from the relay node indicating rejection of the target node to establish the connection.

[0098] In some examples of the seventeenth aspect, the source node or device also includes components or modules for performing one or more examples according to the first aspect.

[0099] According to an eighteenth aspect of the present disclosure, a source node (e.g., a source user equipment or user equipment (UE)) or an apparatus in such a source node is provided. The source node or apparatus according to the eighteenth aspect includes: a component (sending module) for sending a communication request message to a relay node for modifying an existing connection to the relay node to establish a connection to a target node via the relay node; and a component (receiving module) for receiving from the relay node a communication rejection message indicating rejection of modifying the existing connection due to rejection of establishment of the connection by the target node.

[0100] In some examples of the eighteenth aspect, the source node or device also includes components or modules for performing one or more examples according to the first aspect.

[0101] According to a nineteenth aspect of the present disclosure, a source node (e.g., a source user equipment or user equipment (UE)) or an apparatus in such a source node is provided. The source node or apparatus according to the nineteenth aspect includes: a component (sending module) for sending a communication request message to a relay node for establishing a connection to a target node via the relay node by modifying an existing connection between the relay node and the target node; and a component (receiving module) for receiving from the relay node a communication rejection message indicating rejection of establishing a connection between the source node and the relay node due to rejection of modifying the existing connection between the relay node and the target node.

[0102] In some examples of the nineteenth aspect, the source node or device also includes components or modules for performing one or more examples according to the first aspect.

[0103] According to the twentieth aspect of the present disclosure, a relay node (e.g., a relay user equipment or user equipment (UE)) or an apparatus in such a relay node is provided. The relay node or apparatus according to the twentieth aspect includes: a component (receiving module) for receiving a communication request message for establishing a connection to a target node via the relay node from a source node; a component (establishing module) for establishing a connection to the target node; and a component (sending module) for sending a communication rejection message indicating the rejection of the connection establishment by the target node to the source node in response to receiving the rejection of the connection establishment by the target node.

[0104] In some examples of the twentieth aspect, the relay node or device further includes components or modules for performing one or more examples according to the fourth aspect.

[0105] According to the twenty-first aspect of the present disclosure, a relay node (e.g., a relay user equipment or user equipment (UE)) or an apparatus in such a relay node is provided. The relay node or apparatus according to the twenty-first aspect includes: a component (receiving module) for receiving a communication request message for establishing a connection from a source node to a target node via the relay node from another relay node; a component (establishing module) for establishing a connection to the target node; and a component (sending module) for sending a communication rejection message indicating the rejection of the connection establishment by the target node to the other relay node in response to receiving the rejection of the connection establishment by the target node.

[0106] In some examples of the twenty-first aspect, the relay node or device also includes components or modules for performing one or more examples according to the fourth aspect.

[0107] According to the twenty-second aspect of the present disclosure, a relay node (e.g., a relay user equipment or user equipment (UE)) or an apparatus in such a relay node is provided. The relay node or apparatus according to the twenty-second aspect includes: a component for receiving, from another relay node, a communication request message for modifying an existing connection to the relay node to establish a connection from a source node to a target node via the relay node; establishing a connection to the target node (receiving module); and a component for sending, to another relay node in response to receiving a rejection of the target node for establishing the connection, a communication rejection message indicating a rejection of modifying the existing connection due to the rejection of the target node for establishing the connection (sending module).

[0108] In some examples of the twenty-second aspect, the relay node or device also includes components or modules for performing one or more examples according to the fourth aspect.

[0109] According to the twenty-third aspect of the present disclosure, a relay node (e.g., a relay user equipment or user equipment (UE)) or an apparatus in such a relay node is provided. The relay node or apparatus according to the twenty-third aspect includes: a component (receiving module) for receiving a communication request message for establishing a connection from a source node to a target node via a relay node by modifying an existing connection between the relay node and the target node from another relay node; a component (modifying module) for modifying the existing connection to the target node; and a component (sending module) for sending a communication rejection message to another relay node indicating a rejection of establishing a connection from the source node to the target node due to the rejection of modifying the existing connection between the relay node and the target node in response to receiving a rejection of modifying the existing connection by the target node.

[0110] In some examples of the twenty-third aspect, the relay node or device also includes components or modules for performing one or more examples according to the fourth aspect.

[0111] According to the twenty-fourth aspect of the present disclosure, a computer program product includes program instructions stored on a computer-readable medium to perform the steps of any one of the examples of the method according to the first to ninth aspects described above when the program is executed on a computer.

[0112] According to the twenty-fifth aspect of the present disclosure, a non-transitory computer-readable medium containing computer-executable instructions, which, when executed on one or more processors, can perform the steps of any one of the examples of the method according to the first to ninth aspects as described above.

[0113] Depending on the desired configuration, the above aspects and features can be implemented in systems, apparatuses, methods, articles and / or non-transitory computer-readable media. The present disclosure can be implemented in and / or used with a variety of different types of devices, including but not limited to cellular phones, tablet computers, wearable computing devices, portable media players, and any of a variety of other computing devices.

[0114] This summary is intended to provide a brief overview of some aspects and features of the present disclosure. Therefore, it should be understood that the above features are merely examples and should not be construed as narrowing the scope of the present disclosure in any way. Other features, aspects, and advantages of the present disclosure will become apparent from the following detailed description, accompanying drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0115] A better understanding of the present disclosure may be obtained when considering the following detailed description of various embodiments in conjunction with the following drawings, in which:

[0116] Figure 1A schematic diagram illustrating an example wireless network is shown;

[0117] Figure 2 A schematic diagram illustrating an example wireless device is shown;

[0118] Figure 3 A schematic diagram of an example network node is shown;

[0119] Figure 4 illustrates an exemplary reference architecture as described in 3GPP TS 23.304 for Release 18;

[0120] Figure 5 illustrates an example of a procedure for 5G ProSe communication via a 5G ProSe UE-to-UE relay as described in 3GPP TS 23.304 for Release 18;

[0121] Figure 6 illustrates a method of relaying a connection between nodes performed at a source node according to some embodiments;

[0122] Figure 7 illustrates a method of relaying a connection between nodes performed at a relay node according to some embodiments;

[0123] Figure 8 The diagram shows some embodiments according to the present disclosure. Figure 6 and Figure 7 An exemplary message sequence chart corresponding to the method of relaying connections between nodes shown in ;

[0124] Figure 9 illustrates a method of relaying a connection between nodes performed at a source node according to some embodiments;

[0125] Figure 10 illustrates a method of relaying a connection between nodes performed at a relay node according to some embodiments;

[0126] Figure 11 The diagram shows some embodiments according to the present disclosure. Figure 9 and Figure 10 An exemplary message sequence chart corresponding to the method of relaying connections between nodes shown in ;

[0127] Figure 12 illustrates a method of relaying a connection between nodes performed at a source node according to some embodiments;

[0128] Figure 13 illustrates a method of relaying a connection between nodes performed at a relay node according to some embodiments;

[0129] Figure 14The diagram shows some embodiments according to the present disclosure. Figure 12 and Figure 13 An exemplary message sequence chart corresponding to the method of relaying connections between nodes shown in ; and

[0130] Figure 15 An exemplary message sequence chart corresponding to a method of relaying a connection between nodes according to some embodiments of the present disclosure (multi-hop scenario) is illustrated. DETAILED DESCRIPTION

[0131] The examples and embodiments set forth below represent information that will enable those skilled in the art to practice the present disclosure. After reading the following description with reference to the accompanying drawings, those skilled in the art will understand the concepts in this description and will recognize applications of these concepts not specifically addressed herein. It should be understood that these concepts and applications fall within the scope of this description.

[0132] In the following description, numerous specific details are set forth. However, it should be understood that the embodiments can be practiced without these specific details. In other instances, well-known circuits, structures, and techniques are not shown in detail in order not to obscure the understanding of this description. With the included description, one of ordinary skill in the art will be able to implement appropriate functionality without undue experimentation.

[0133] References in this specification to "one embodiment," "an embodiment," and "an example embodiment" indicate that the described embodiment may include a particular feature, structure, or characteristic, but not every embodiment must include the particular feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Furthermore, when a particular feature, structure, or characteristic is described in conjunction with an embodiment, those skilled in the art recognize that it is within the knowledge of those skilled in the art to implement such feature, structure, or characteristic in conjunction with other embodiments, whether or not explicitly described.

[0134] As used herein, "plurality" means two or more, while "a" means one or more. As used herein, a collection of items may include one or more such items. As used herein, whether in the present disclosure or in the claims, the terms "comprising," "including," "carrying," "having," "containing," "involving," and the like should be understood as open-ended, i.e., meaning including but not limited to. Only the transition phrases "consisting of" and "consisting mainly of" are closed or semi-closed transition phrases with respect to the claims, respectively. The use of ordinal terms such as "first," "second," and "third" to modify elements in the claims or in the present disclosure does not, by itself, indicate any priority, precedence, or order of one element relative to another, nor does it indicate the temporal order in which the acts of the method are performed, but is merely used as a label to distinguish an element with a particular name from another element with the same name (but using ordinal terms) to distinguish these elements. As used herein, "and / or" and "at least one of" indicate that the listed items are alternatives, but alternatives also include any combination of the listed items.

[0135] Before explaining the examples according to the present disclosure in detail, Figures 1 to 3 Certain general principles of wireless communication systems are briefly explained to aid understanding of the technology on which the described examples are based.

[0136] Figure 1 An example of a wireless network 100 that can be used for wireless communications is illustrated. The wireless network 100 includes wireless devices, such as UEs 110 (e.g., 110A, 110B, 110C), and network nodes, such as radio access nodes 120 (e.g., 120A, 120B) (e.g., eNBs, gNBs, etc.), connected to one or more network nodes 130 via an interconnection network 125. The network 100 can use any suitable deployment scenario. Each of the UEs 110 within a coverage area 115 can communicate directly with the radio access node 120 via a wireless interface. In some embodiments, the UEs 110 can also communicate with each other via D2D communications. For example, UE 110A can communicate with UE 110C via UE 110B. In this scenario, UE 110B acts as a relay, such that the communication between UE 110A and UE 110C is indirect (relay) communication.

[0137] Furthermore, UE 110A may communicate with radio access node 120A via a wireless interface. That is, UE 110A may send wireless signals to and / or receive wireless signals from radio access node 120A. The wireless signals may include voice traffic, data traffic, control signals, and / or any other suitable information.

[0138] As used herein, the term "user equipment" (UE) has the full breadth of its ordinary meaning and may refer to any type of wireless device that can communicate with a network node and / or another UE in a cellular or mobile or wireless communication system. Examples of UEs are target devices, D2D UEs, machine type UEs or UEs capable of machine-to-machine (M2M) communication, personal digital assistants, tablet computers, mobile terminals, smartphones, laptop embedded devices (LEEs), laptop mounted devices (LMEs), USB dongles, ProSe UEs, vehicle-to-vehicle (V2V) UEs, V2X UEs, MTC UEs, eMTC UEs, FeMTC UEs, UE Cat 0, UE Cat M1, narrowband IoT (NB-IoT) UEs, UE Cat NB1, etc. Reference is made below to Figure 2 Example embodiments of the UE are described in more detail.

[0139] In some embodiments, the wireless signal coverage area 115 associated with the radio access node 120 may be referred to as a cell. However, particularly with respect to 5G concepts, beams may be used instead of cells, and therefore, it is important to note that the concepts described herein apply equally to both cells and beams.

[0140] The interconnection network 125 may refer to any interconnection system capable of transmitting audio, video, signals, data, messages, etc., or any combination thereof. The interconnection network 125 may include all or part of the following: a public switched telephone network (PSTN), a public or private data network, a local area network (LAN), a metropolitan area network (MAN), a wide area network (WAN), a local, regional, or global communication or computer network (such as the Internet), a wired or wireless network (such as a public land mobile network (PLMN)), 4G and 5G networks, an enterprise intranet, or any other suitable communication link (including combinations thereof).

[0141] In some embodiments, network node 130 may be a core network node that manages establishment of communication sessions and various other functions for UE 110. UE 110 may use a non-access stratum (NAS) layer to exchange certain signals with network node 130. In non-access stratum signaling, signals between UE 110 and network node 130 may be transparently transferred through a radio access network.

[0142] As used herein, the term "network node" has the full breadth of its ordinary meaning and may correspond to any type of radio access node (or radio network node) or any network node that may communicate with a UE and / or with another network node in a cellular, mobile or wireless communication system. Examples of network nodes are NodeB, MeNB, SeNB, a network node that may belong to an MCG or an SCG, a base station (BS), a multi-standard radio (MSR) radio access node (such as an MSR BS), an eNodeB, a network controller, a radio network controller (RNC), a base station controller (BSC), a relay, a base transceiver station (BTS), an access point (AP), a transmission point, a transmission node, a core network node (e.g., an MSC, an MME, etc.), etc. Reference is made below to Figure 3 Example embodiments of network nodes are described in further detail.

[0143] In some embodiments, the radio access node 120 may be a distributed radio access node. The components of the radio access node 120 and their associated functions may be separated into two main units (or sub-radio network nodes), which may be referred to as a central unit (CU) and a distributed unit (DU). Different distributed radio network node architectures are possible. For example, in some architectures, the DU may be connected to the CU via a dedicated wired or wireless link (e.g., a fiber optic cable), while in other architectures, the DU may be connected to the CU via a transport network. In addition, the manner in which the various functions of the radio access node 120 are separated between (multiple) CUs and (multiple) DUs may vary depending on the selected architecture.

[0144] An exemplary wireless communication system is an architecture standardized by the Third Generation Partnership Project (3GPP). Developments based on the latest 3GPP are generally referred to as the Long Term Evolution (LTE) of the Universal Mobile Telecommunications System (UMTS) radio access technology (RAT). The various stages of development of the 3GPP specifications are referred to as releases. The latest development of LTE is generally referred to as Advanced LTE (LTE-A). LTE (LTE-A) uses a radio mobile architecture called the Evolved Universal Terrestrial Radio Access Network (E-UTRAN) and a core network called the Evolved Packet Core (EPC). The base stations of such systems are called evolved or enhanced Node Bs (eNBs) and provide E-UTRAN features towards communication devices, such as user plane packet data convergence / radio link control / media access control / physical layer protocols (PDCP / RLC / MAC / PHY) and control plane radio resource control (RRC) protocol termination. Other RAT examples include those provided by base stations of systems based on technologies such as WLAN and / or Worldwide Interoperability for Microwave Access (WiMax). A base station can provide coverage for an entire cell or similar radio service area. Core network elements include the Mobility Management Entity (MME), the Serving Gateway (S-GW), and the Packet Gateway (P-GW).

[0145] Examples of suitable communication systems are 5G or NR concepts. The network architecture in NR can be similar to LTE-A. The base stations of NR systems can be referred to as next-generation Node Bs (gNBs). Changes in network architecture can be driven by the need to support various radio technologies and more refined quality of service (QoS) support, as well as some on-demand requirements for QoS levels to support quality of experience (QoE) from the user's perspective. NR can use multiple-input multiple-output (MIMO) antennas, more base stations or nodes than LTE (the so-called small cell concept), including macro sites operating in cooperation with smaller sites, and perhaps also various radio technologies for better coverage and enhanced data rates.

[0146] Future networks may utilize network function virtualization (NFV), which is a network architecture concept that proposes virtualizing network node functions into "building blocks" or entities that can be operationally connected or linked together to provide services. A virtualized network function (VNF) may include one or more virtual machines that use standard or general-purpose servers rather than custom hardware to run computer program code. Cloud computing or data storage may also be utilized. In radio communications, this may mean that node operations may be performed at least in part in a server, host, or node that is operably coupled to a remote radio head. Node operations may also be distributed among multiple servers, nodes, or hosts. It should also be understood that the workload distribution between core network operations and base station operations may be different from that of LTE, or even non-existent.

[0147] An example 5G core network (CN) includes functional entities. The CN is connected to the UE via the radio access network (RAN). The UPF (User Plane Function), whose role is called PSA (PDU Session Anchor), can be responsible for forwarding frames back and forth between the DN (Data Network) and the tunnel established over 5G, which is destined for the UE exchanging traffic with the Data Network (DN). The UPF is controlled by the SMF (Session Management Function), which receives policies from the PCF (Policy Control Function). The CN may also include the AMF (Access and Mobility Function).

[0148] Figure 2 is a schematic diagram of an example wireless device, UE 110, according to certain embodiments. UE 110 includes a transceiver 210, a processor 220, a memory 230, and a network interface 240. In some embodiments, transceiver 210 facilitates the transmission and reception of wireless signals to and from radio access node 120 (e.g., via transmitter(s) (Tx), receiver(s) (Rx), and antenna(s). Processor 220 executes instructions to provide some or all of the functionality described herein as provided by UE 110, and memory 230 stores instructions executed by processor 220. In some embodiments, processor 220 and memory 230 form processing circuitry.

[0149] The processor 220 may include any suitable combination of hardware for executing instructions and manipulating data to perform some or all of the functions described for a wireless device, such as the functions described herein for the UE 110. In some embodiments, the processor 220 may include, for example, one or more computers, one or more central processing units (CPUs), one or more microprocessors, one or more application specific integrated circuits (ASICs), one or more field programmable gate arrays (FPGAs), and / or other logic.

[0150] The memory 230 is generally operable to store instructions, such as computer programs, software, applications (including one or more of the following: logic, rules, algorithms, code, tables, etc.), and / or other instructions that can be executed by the processor 220. Examples of the memory 230 include computer memory (e.g., random access memory (RAM) or read-only memory (ROM)), mass storage media (e.g., hard disk), removable storage media (e.g., compact disk (CD) or digital video disk (DVD)), and / or any other volatile or non-volatile, non-transitory computer-readable and / or computer-executable memory device that stores information, data and / or instructions that can be used by the processor 220 of the UE 110. For example, the memory 230 includes instructions that enable the processor 220 to execute instructions according to the following references. Figures 4 to 15The method described is performed by processing computer program code.

[0151] The network interface 240 is communicatively coupled to the processor 220 and may refer to any suitable device operable to receive input for the UE 110, send output from the UE 110, perform appropriate processing of the input or output or both, communicate with other devices, or any combination thereof. The network interface 240 may include appropriate hardware (e.g., a port, a modem, a network interface card, etc.) and software (including protocol conversion and data processing capabilities) to communicate over a network.

[0152] Other embodiments of UE 110 may include Figure 2 Additional components beyond those shown may be responsible for providing certain aspects of the functionality of the wireless device, including any functionality described herein and / or any additional functionality (including any functionality required to support mechanisms according to the present disclosure). As an example, the UE 110 may include input devices and circuits, output devices, and one or more synchronization units or circuits, which may be part of the processor 220. The input devices include mechanisms for entering data into the UE 110. For example, the input devices may include input mechanisms such as a microphone, an input element, a display, etc. The output devices may include mechanisms for outputting data in audio, video, and / or hard copy formats. For example, the output devices may include speakers, a display, etc.

[0153] In some embodiments, the wireless device UE 110 may include a series of modules configured to implement the functionality of the wireless device described herein.

[0154] It should be understood that the various modules may be implemented as a combination of hardware and software, e.g. Figure 2 The processor, memory, and transceiver(s) of UE 110 are shown in FIG. Some embodiments may also include additional modules that support additional and / or optional functionality.

[0155] Figure 33 is a schematic diagram of an example radio access node 120 or network node 130. The example radio access node 120 or network node 130 may include one or more of the following: a transceiver 310, a processor 320, a memory 330, and a network interface 340. In some embodiments, the transceiver 310 facilitates the transmission and reception of wireless signals to and from wireless devices, such as the UE 110 (e.g., via transmitter(s) (Tx), receiver(s) (Rx), and antenna(s)). The processor 320 executes instructions to provide some or all of the functionality described herein as provided by the radio access node 120 or network node 130, and the memory 330 stores instructions executed by the processor 320. In some embodiments, the processor 320 and the memory 330 form processing circuitry. The network interface 340 may transmit signals to backend network components, such as a gateway, a switch, a router, the Internet, a public switched telephone network (PSTN), a core network node, or a radio network controller.

[0156] The processor 320 may include any suitable combination of hardware that executes instructions and manipulates data to perform some or all of the functions of the radio access node 120 or the network node 130, such as those described herein. In some embodiments, the processor 320 may include, for example, one or more computers, one or more central processing units (CPUs), one or more microprocessors, one or more application specific integrated circuits (ASICs), one or more field programmable gate arrays (FPGAs), and / or other logic.

[0157] The memory 330 is generally operable to store instructions, such as computer programs, software, applications (including one or more of the following: logic, rules, algorithms, codes, tables, etc.), and / or other instructions that can be executed by the processor 320. Examples of the memory 330 include computer memory (e.g., random access memory (RAM) or read-only memory (ROM)), mass storage media (e.g., hard disk), removable storage media (e.g., compact disk (CD) or digital video disk (DVD)), and / or any other volatile or non-volatile, non-transitory computer-readable and / or computer-executable memory device that stores information. For example, the memory 330 includes instructions that enable the processor 320 to execute instructions according to the following references. Figure 11 The method described is performed by processing computer program code.

[0158] In some embodiments, the network interface 340 is communicatively coupled to the processor 320 and may refer to any suitable device operable to receive input for the radio access node 120 or the network node 130, send output from the radio access node 120 or the network node 130, perform appropriate processing of the input or output or both, communicate with other devices, or any combination of the foregoing. The network interface 340 may include appropriate hardware (e.g., a port, a modem, a network interface card, etc.) and software (including protocol conversion and data processing capabilities) to communicate over a network.

[0159] Other embodiments of the radio access node 120 or the network node 130 may include Figure 3 , which additional components may be responsible for providing certain aspects of the functionality of the node, including any functionality described herein and / or any additional functionality (including any functionality required to support the solutions described herein). Various different types of radio access nodes or network nodes may include components having the same physical hardware but configured (e.g., via programming) to support different radio access technologies, or may represent partial or completely different physical components.

[0160] With reference Figure 3 Similar processors, interfaces, and memories to those described may be included in other nodes such as UE 110, radio access node 120, etc. Other nodes may optionally include or not include a wireless interface such as Figure 3 transceiver described in ).

[0161] In some embodiments, the radio access node 120 or the network node 130 may include a series of modules configured to implement the functionality of the radio access node 120 or the network node 130 described herein.

[0162] It will be understood that the various modules may be implemented as a combination of hardware and software, e.g. Figure 3 The processor, memory and transceiver(s) of the radio access node 120 or network node 130 are shown in FIG. Some embodiments may also include additional modules that support additional and / or optional functionality.

[0163] In reference Figures 6 to 15 Before describing the method of relaying connections between nodes according to some embodiments of the present disclosure, some background information and aspects related to the present disclosure will be provided.

[0164] In 3GPP TS 23.304 for Release 18 (V18.0.0, Version 2022-12) (incorporated herein by reference), Proximity-Based Services (ProSe) features in 5GS are specified. These 5G ProSe features include 5G ProSe UE-to-UE relay, which enables indirect communication between two 5G ProSe terminals (also referred to herein as a relay connection between nodes).

[0165] An exemplary reference architecture as described in 3GPP TS 23.304 for Release 18 is Figure 4 More specifically, the exemplary reference architecture shows a layer 2 and layer 3 5G ProSe UE-to-UE relay reference architecture.

[0166] exist Figure 4 In the figure, two 5G ProSe terminals UE are shown, which communicate with each other via a 5G ProSe UE-to-UE relay. Each 5G ProSe terminal UE and the 5G ProSe UE-to-UE relay can have subscriptions from the same public land mobile network (PLMN) or different PLMNs. 3GPP TS 23.304 for Release 18 specifies the PC5 reference point between UEs that support 5G ProSe requirements and associated procedures (referred to as ProSe-enabled UEs), such as each 5G ProSe terminal UE and the 5G ProSe UE-to-UE relay. The PC5 reference point is used for the control and user planes for procedures adopted by a 5G ProSe-enabled UE: discovering other 5G ProSe-enabled UEs in its vicinity based on direct radio transmission between two UEs using NR technology (referred to as 5G ProSe direct discovery); communicating between two or more neighboring 5G ProSe-enabled UEs through user plane transmission using NR technology via a path that does not pass through any network nodes (referred to as 5G ProSe direct communication); providing a 5G ProSe-enabled UE that supports connectivity between 5G ProSe terminal UEs (referred to as 5G ProSe UE-to-UE relay); and / or providing a 5G ProSe-enabled UE that supports connectivity to a network for a 5G ProSe-enabled UE communicating with a data network (DN) via a 5G ProSe UE-to-network relay (referred to as 5G ProSe UE-to-network relay).

[0167] 3GPP TS 23.304 for Release 18 also specifies that any 5G ProSe-enabled UE may support the following: procedures for 5G ProSe direct communication over the PC5 reference point, including 5G ProSe direct communication in broadcast, multicast, and unicast modes; procedures for acting as a 5G ProSe Layer 2 UE-to-UE relay; procedures for acting as a 5G ProSe Layer 3 UE-to-UE relay; procedures for acting as a 5G ProSe Layer 2 terminating UE; and procedures for acting as a 5G ProSe Layer 3 terminating UE.

[0168] Examples of procedures for 5G ProSe communication via 5G ProSe UE-to-UE relay are described in 3GPP TS 23.304 for Release 18 and in Figure 5 is shown in the figure.

[0169] like Figure 5 As shown in , a source 5G ProSe layer 3 terminal UE (i.e., source node) communicates with a target 5G ProSe layer 3 terminal UE (i.e., target node) via a 5G ProSe layer 3 UE-to-UE relay (i.e., relay node). The source 5G ProSe layer 3 terminal UE, the target 5G ProSe layer 3 terminal UE, and the 5G ProSe layer 3 UE-to-UE relay may be connected to the same PLMN or different PLMNs.

[0170] In step 1, service authorization and configuration are performed for the source 5G ProSe layer 3 terminal UE, the target 5G ProSe layer 3 terminal UE and the 5G ProSe layer 3 UE-to-UE relay. The procedures for service authorization and configuration to the UE are described in 3GPP TS 23.304 for Release 18.

[0171] In step 2, the source 5G ProSe layer 3 terminal UE performs discovery of 5G ProSe layer 3 UE-to-UE relays. The discovery process is described in 3GPP TS 23.304 for Release 18.

[0172] In step 3, the source 5G ProSe layer 3 terminal UE sends a direct communication request message to initiate a unicast layer 2 link establishment procedure with the 5G ProSe layer 3 UE-to-UE relay. The source layer 2 ID of the direct communication request message is self-assigned by the source 5G ProSe layer 3 terminal UE, and the destination layer 2 ID is set to the source layer 2 ID of the discovery message of the 5G ProSe layer 3 UE-to-UE relay.

[0173] In step 4, if the user information ID of the target 5G ProSe layer 3 terminal UE and the user information ID of the 5G ProSe layer 3 UE-to-UE relay are included in the direct communication request message, the 5G ProSe layer 3 UE-to-UE relay responds by establishing security with the source 5G ProSe layer 3 terminal UE. When security protection is enabled, the source 5G ProSe layer 3 terminal UE sends IP address configuration and QoS information to the 5G ProSe layer 3 UE-to-UE relay. The source layer 2 ID used for the security establishment procedure is assigned by the 5G ProSe layer 3 UE-to-UE relay, and the destination layer 2 ID is set to the source layer 2 ID of the received direct communication request message. After receiving the security establishment procedure message, the source 5G ProSe layer 3 terminal UE obtains the layer 2 ID of the 5G ProSe layer 3 UE-to-UE relay for future communications, for signaling and data traffic for this unicast link.

[0174] In step 5, after the security establishment procedure is completed, the 5G ProSe layer 3 UE-to-UE relay sends a direct communication request message to initiate a unicast layer 2 link establishment procedure with the target 5G ProSe layer 3 terminal UE. The source layer 2 ID of the direct communication request message is allocated by the 5G ProSe layer 3 UE-to-UE relay, and the destination layer 2 ID is the unicast layer 2 ID of the target 5G ProSe layer 3 terminal UE associated with the user information ID of the target 5G ProSe layer 3 terminal UE.

[0175] In step 6, if the user information ID of the target 5G ProSe layer 3 terminal UE is included in the direct communication request message, the target 5G ProSe layer 3 terminal UE responds by establishing security with the 5G ProSe layer 3 UE-to-UE relay. When security protection is enabled, the 5G ProSe layer 3 UE-to-UE relay sends the IP address configuration and QoS information to the target 5G ProSe layer 3 terminal UE. The source layer 2 ID used for the security establishment procedure is self-assigned by the target 5G ProSe layer 3 terminal UE, and the destination layer 2 ID is set to the source layer 2 ID of the received direct communication request message. After receiving the security establishment procedure message, the 5G ProSe layer 3 UE-to-UE relay obtains the layer 2 ID of the target 5G ProSe layer 3 terminal UE for future communications, for signaling and data traffic for this unicast link.

[0176] In step 7, the target 5G ProSe layer 3 terminal UE sends a direct communication accept message to the 5G ProSe layer 3 UE-to-UE relay for which security has been successfully established.

[0177] Optionally, for Internet Protocol (IP) traffic, in step 8, an IP address is allocated for the target 5G ProSe layer 3 terminal UE.

[0178] In step 9, after receiving the direct communication accept message from the target 5G ProSe layer 3 terminal UE, the 5G ProSe layer 3 UE-to-UE relay sends a direct communication accept message to the source 5G ProSe layer 3 terminal UE for which security has been successfully established.

[0179] Optionally, for IP traffic, in step 10, the IP address of the source 5G ProSe layer 3 terminal UE is used, and the 5G ProSe layer 3 UE-to-UE relay and the source 5G ProSe layer 3 terminal UE exchange domain name service (DNS) messages (steps 11a and 11b).

[0180] In step 12, the source 5G ProSe layer 3 terminal UE communicates with the target 5G ProSe layer 3 terminal UE via the 5G ProSe layer 3 UE-to-UE relay. That is, the source 5G ProSe layer 3 terminal UE is performing relay communication with the target 5G ProSe layer 3 terminal UE via the 5G ProSe layer 3 UE-to-UE relay.

[0181] Signaling messages for direct communication between a source 5G ProSe layer 3 terminal UE and a target 5G ProSe layer 3 terminal UE over the PC5 reference point are described in the 5G ProSe direct link establishment procedure of 3GPP TS 24.554 for Release 17 (Version V17.3.02022-12) (incorporated herein by reference). According to the 5G ProSe direct link establishment procedure, an initiating UE (e.g., a source 5G ProSe layer 3 terminal UE) sends a PROSE DIRECT LINK ESTABLISHMENT REQUEST message to a target UE (e.g., a 5G ProSe layer 3 UE-to-UE relay). The target UE may accept the direct link establishment request by returning a PROSE DIRECT LINK ESTABLISHMENT ACCEPT message to the initiating UE, or may reject the direct link establishment request by returning a PROSE DIRECT LINK ESTABLISHMENT REJECT message to the initiating UE. Figure 5 Steps 3 and 9 represent the 5G ProSe direct link establishment procedure between the source 5G ProSe layer 3 terminal UE as the initiating UE and the 5G ProSe layer 3 UE-to-UE relay as the target UE. Figure 5Steps 5 and 7 represent the 5G ProSe direct link establishment procedure between the 5G ProSe layer 3 UE-to-UE relay as the target UE and the target 5G ProSe layer 3 terminal UE as the target UE.

[0182] According to 3GPP TS 24.554 for Release 17, the target UE may reject the 5G PROSE direct link establishment request by sending a PROSE DIRECT LINK ESTABLISHMENT REJECT message to the initiating UE. To inform the initiating UE of the reason for rejecting the 5G PROSE DIRECT LINK ESTABLISHMENT REQUEST, as described in 3GPP TS 24.554 for Release 17, the PROSE DIRECT LINK ESTABLISHMENT REJECT message includes an information element "PC5 signaling protocol cause" that reserves the protocol cause for the rejection.

[0183] The initiating UE uses the "PC5 signaling protocol cause" information to decide whether the failure (i.e., rejection) is permanent or temporary and take appropriate next steps. Based on the protocol cause for the rejection, the initiating UE decides to retry connection establishment with the same target UE or whether the initiating UE needs to perform a relay reselection procedure to find another relay UE.

[0184] In some examples, a direct communication (i.e., connection) between a source 5G ProSe layer 3 terminal UE and a 5G ProSe layer 3 UE-to-UE relay and / or between a 5G ProSe layer 3 UE-to-UE relay and a target 5G ProSe layer 3 terminal UE may already be established and may be used. In this case, a PROSE DIRECT LINK MODIFICATION REQUEST message may be used to modify the (existing) direct communication, possibly in a modified manner. If the modification of the (existing) direct communication is accepted, a PROSE DIRECT LINK MODIFICATION ACCEPT message may be used, whereas if the modification is rejected, a PROSE DIRECT LINK MODIFICATION REJECT message may be used. In order to inform the initiating UE about the reason for rejecting the 5G ProSe direct link modification request, the PROSE DIRECT LINK MODIFICATION REJECT message includes the information element "PC5 signaling protocol cause", which reserves the protocol cause for the rejection, similar to the PROSE DIRECT LINK ESTABLISHMENT REJECT message.

[0185] However, if a failure / rejection occurs between the 5G ProSe Layer 3 UE-to-UE relay and the target 5G ProSe Layer 3 terminal UE, a problem arises because the source 5G ProSe Layer 3 terminal UE is not notified of the cause for the failure / rejection from the target 5G ProSe Layer 3 terminal UE. Therefore, the source 5G ProSe Layer 3 terminal UE cannot utilize information about the failure / rejection that occurred between the 5G ProSe Layer 3 UE-to-UE relay and the target 5G ProSe Layer 3 terminal UE, and therefore cannot take appropriate subsequent actions.

[0186] The present disclosure provides a mechanism for relaying connections between nodes (i.e., a source 5G ProSe terminal UE and a target 5G ProSe terminal UE) that helps solve the above-mentioned problem. The present disclosure addresses this problem and thus enables the source 5G ProSe terminal UE to utilize information about failures / rejections that occur between the 5G ProSe UE-to-UE relay and the target 5G ProSe terminal UE, so that the source 5G ProSe terminal UE can take appropriate subsequent actions in the event of failures / rejections.

[0187] Now, an exemplary method of relaying connections between nodes according to some embodiments of the present disclosure will be described.

[0188] Figure 6 Illustrated is a method 600 of relaying connections between nodes according to some embodiments.

[0189] The method 600 is performed by a source node such as a user equipment (e.g., user equipment (UE)) or by an apparatus used in a source node. The source node includes a 5G ProSe-enabled UE and represents a source 5G ProSe terminal UE as described above. In some examples, the source node can be represented by any one of the wireless devices, such as the wireless device described above. Figure 1 The UE 110A of the wireless network 100, or the ... Figure 2 The wireless device 110.

[0190] The relay node may be a user equipment (e.g., user equipment (UE)) or an apparatus for use in a relay node. The relay node includes a 5G ProSe-enabled UE and represents a 5G ProSe UE-to-UE relay as described above. In some examples, the relay node may be represented by any one of the wireless devices, such as those described above with reference to Figure 1 The UE 110B of the wireless network 100, or the ... Figure 2 The wireless device 110.

[0191] The target node may also be a user equipment (e.g., user equipment (UE)) or an apparatus for use in a target node. The target node includes a 5G ProSe-enabled UE and represents a target 5G ProSe terminal UE as described above. In some examples, the target node may be represented by any one of the wireless devices, such as the wireless device described above. Figure 1 The UE 110C of the wireless network 100, or the ... Figure 2 The wireless device 110.

[0192] The source node, relay node, and target node are connected to and served by the network 100. More specifically, the source node, relay node, and target node are located in an area (i.e., cell 115) served by a base station (e.g., gNB 120A, 120B) and use services provided or supported by the network 100. For example, the network 100 may support Proximity-Based Services (ProSe), which enables 5G ProSe communication via a 5G ProSe UE-to-UE relay (i.e., indirect / relay communication via a relay). As described above, the source node, relay node, and target node may be connected to the same PLMN or different PLMNs.

[0193] The method 600 begins at block 610. At block 610, a source node sends a communication request message to a relay node for establishing a connection to a target node via the relay node. Using the communication request message, the source node requests to establish a first direct connection (also referred to as a first hop) between the source node and the relay node, and a second direct connection (also referred to as a second hop) between the relay node and the target node, thereby establishing an indirect connection from the source node to the target node via the relay node.

[0194] In some examples, the communication request message for establishing the connection includes a PROSE DIRECT LINK ESTABLISHMENT REQUEST message.

[0195] Additionally, the source node may start a timer (e.g., T5080) in response to sending a communication request message to the relay node. The timer indicates a time period within which the source node will receive a response (acceptance or rejection) to the communication request message from the target node. If the timer expires without receiving a response, the source node may resend the communication request message to the relay node if a connection to the target node is still to be established.

[0196] At block 620, the source node receives a communication rejection message from the relay node indicating the destination node's rejection of establishing a connection. Using the communication rejection message, the relay node indicates to the source node, and thus informs the source node, that the destination node refuses to establish the second direct connection. In other words, establishing the second direct connection resulted in a failure or rejection, such that the second hop cannot be established. Due to the failure or rejection, the connection requested by the source node to the destination node is not established.

[0197] In some examples, the communication rejection message indicating rejection of establishing the connection includes a PROSE DIRECT LINK ESTABLISHMENT REJECT message.

[0198] In some examples, the communication rejection message includes a cause value (i.e., one or more cause values) for indicating rejection by the target node. For example, a PROSE DIRECT LINK ESTABLISHMENT REJECT message may include a PC5 failure cause that indicates to the source node that the establishment of the connection was rejected and therefore failed due to a connection rejection from the target node, rather than a rejection from the relay node. As will be described in more detail below, the new PC5 failure cause may be used to indicate to the source 5G ProSe terminal UE that "the failure was due to a connection rejection from the target 5G ProSe terminal UE, rather than a rejection from the 5G ProSe UE-to-UE relay itself."

[0199] In some examples, a cause value indicating a rejection by the target node may be included in an existing information element (IE) in a communication rejection message that is used to signal a cause value to a relay node. For example, a PROSE DIRECT LINK ESTABLISHMENT REJECT message includes an IE (e.g., a PC5 signaling protocol cause IE) that indicates a cause value from the relay node to the source node. The above IE may be used to indicate a rejection by the target node and, therefore, may also be extended to indicate a cause value for the target node. As described below, a new PC5 failure cause may be provided in an existing PC5 signaling protocol cause IE that is used to signal a rejection cause for 5G ProSe UE-to-UE relaying.

[0200] Additionally or alternatively, in some examples, the communication rejection message may include an additional IE for signaling a cause value for the target node. The additional IE is used to indicate a rejection by the target node and provides additional details (i.e., a cause value) indicating to the source node why the connection establishment was rejected by the target node. The additional IE may be optional and is included in the communication rejection message if an existing IE indicates a rejection by the target node. That is, in some examples, an existing IE for signaling a cause value for the relay node in the communication rejection message indicates to the source node that the failure is due to a connection rejection from the target node, while the additional IE provides a cause value indicating the cause for the connection rejection by the target node. As described below, an additional PC5 terminal UE failure cause IE may be included in the PROSEDIRECT LINK ESTABLISHMENT REJECT message. The PC5 terminal UE failure cause IE carries the rejection cause provided by the target node (i.e., the target 5G ProSe terminal UE itself) and is included when a new PC5 failure cause is provided by the PC5 signaling protocol cause IE. When generating a PROSE DIRECT LINK ESTABLISHMENT REJECT message, the relay node (i.e., 5G ProSe UE to UE relay) includes an additional PC5 terminal UE failure cause IE and sets the rejection cause value (i.e., one or more rejection cause values) provided by the target node (i.e., target 5G ProSe terminal UE). Based on the rejection cause values ​​in the PC5 signaling protocol cause IE and the PC5 terminal UE failure cause IE, the source node (i.e., source 5G ProSe terminal UE) is informed of the reason why the target node (i.e., target 5G ProSe terminal UE) has rejected the establishment of the connection (i.e., the PC5 connection between the relay node and the target node).

[0201] In some examples, an existing information element (IE) used to signal a cause value to a relay node in a communication rejection message can also be extended to signal a rejection cause value to a target node. That is, the existing PC5 signaling protocol cause IE in a PROSE DIRECT LINK ESTABLISHMENT REJECT message can be extended by adding multiple additional cause values ​​representing failure situations from the target node (i.e., the target 5G ProSe terminal UE).

[0202] Additionally, in some examples, the source node may stop a timer (eg, T5080) in response to receiving a communication rejection message from the relay node. Before stopping the timer, the source node may check whether the communication rejection message is received before expiration of the timer.

[0203] In some examples, if the source node receives a communication rejection message indicating a rejection by the target node to establish a connection (block 620), the source node may perform a process for processing or coping with the rejection by the target node (block 630). Examples of the above process include a retry process for retrying to establish a connection, a relay reselection process for selecting another relay node via which to establish a connection, and a discovery process for discovering another target node to which to establish a connection.

[0204] In some examples, if the source node receives a communication rejection message indicating a rejection by the target node to establish a connection (block 620), the source node may retry establishing a connection to the target node by sending another communication request message for establishing a connection to the target node via the relay node (block 630A). The process for sending another communication request message corresponds to sending the communication request message of block 610. Preferably, the source node may begin performing retry attempts after a timer expires. For example, in response to receiving the communication rejection message (block 620), the source node may start a timer. When the timer expires, and if a connection to the target node is still to be established, the source node sends another communication request message as a retry to establish a connection to the target node via the relay node.

[0205] In some examples, if the source node receives a communication rejection message indicating a rejection of the target node's request to establish a connection (block 620), the source node may perform a relay reselection process to select another relay node and send a new communication request message for establishing a connection to the target node via the other relay node (block 630B). The process for sending the new communication request message corresponds to sending the communication request message of block 610, but the communication request message is sent to another relay node selected by the relay reselection process instead of being sent to the relay node. To decide whether to perform the relay reselection process, the source node may consider the reason (e.g., one or more reason values) for rejecting the request to establish a connection by the target node, as provided in the communication rejection message.

[0206] In some examples, if the source node receives a communication rejection message (block 620) indicating a rejection of the establishment of a connection by the target node, the source node may also determine whether the rejection by the target node is permanent (block 630C). This determination may be based on the reason (e.g., one or more reason values) for the rejection of the establishment of a connection by the target node as provided in the communication rejection message. If the source node determines that the rejection is permanent, the source node may perform a discovery process to discover another target node to which a connection is established via the relay node or another relay node. In response to discovering the other target node, the source node sends a new communication request message to the relay node or another relay node for establishing a connection to the other target node via the relay node or via another relay node. The process for sending the new communication request message corresponds to sending the communication request message of block 610, but the communication request message is sent toward the other target node.

[0207] Utilizing the method 600, the source node is notified of a refusal due to a refusal by the target node to establish a connection (ie, the second hop) between the relay node and the target node.

[0208] Figure 7 Illustrated is a method 700 of relaying connections between nodes according to some embodiments.

[0209] The method 700 is performed by a relay node such as a user equipment (e.g., user equipment (UE)) or by an apparatus used in a relay node. The relay node includes a 5G ProSe-enabled UE and represents a 5G ProSe UE-to-UE relay as described above. In some examples, the relay node can be represented by any one of the wireless devices, such as the wireless devices described above. Figure 1 The UE 110B of the wireless network 100, or the ... Figure 2 The wireless device 110.

[0210] The source node may be a user equipment (e.g., user equipment (UE)) or an apparatus for use in a source node. The source node includes a 5G ProSe-enabled UE and represents a source 5G ProSe terminal UE as described above. In some examples, the source node may be represented by any one of the wireless devices, such as the wireless device described above. Figure 1 The UE 110A of the wireless network 100, or the ... Figure 2 The wireless device 110.

[0211] The target node may also be a user equipment (e.g., user equipment (UE)) or an apparatus for use in a target node. The target node includes a 5G ProSe-enabled UE and represents a target 5G ProSe terminal UE as described above. In some examples, the target node may be represented by any one of the wireless devices, such as the wireless device described above. Figure 1 The UE 110C of the wireless network 100, or the ... Figure 2 The wireless device 110.

[0212] As described above, the source node, relay node, and target node are connected to and served by the network 100, and may be connected to the same PLMN or different PLMNs.

[0213] The method 700 begins at block 710. At block 710, the relay node receives a communication request message from a source node for establishing a connection to a target node via the relay node. Using the communication request message, the source node requests to establish a first direct connection (i.e., a first hop) between the source node and the relay node, and to establish a second direct connection (i.e., a second hop) between the relay node and the target node, thereby establishing an indirect connection from the source node to the target node via the relay node.

[0214] In some examples, the communication request message for establishing the connection includes a PROSE DIRECT LINK ESTABLISHMENT REQUEST message.

[0215] At block 720, the relay node attempts to establish a connection to the target node (i.e., the second hop). More specifically, the relay node initiates a process for establishing a connection to the target node. For example, the relay node may send a communication request message (e.g., a PROSE DIRECT LINK ESTABLISHMENT REQUEST message) for establishing a connection to the target node and receive a communication acceptance message (e.g., a PROSE DIRECT LINK ESTABLISHMENT ACCEPT message) from the target node to establish a connection between the relay node and the target node, or receive a communication rejection message (e.g., a PROSE DIRECT LINK ESTABLISHMENT REJECT message) from the target node indicating the target node's rejection of establishing the connection.

[0216] If the relay node receives a communication rejection message (i.e., a rejection of the connection establishment by the target node), the relay node sends a communication rejection message to the source node requesting communication to the target node via the relay node, indicating the rejection of the connection establishment by the target node (block 730). With the communication rejection message, the relay node indicates to the source node, and thus informs the source node, that the target node rejects the establishment of the second direct connection. In other words, the establishment of the second direct connection results in a failure or rejection, such that the second hop cannot be established. As a result, due to the failure or rejection, the connection to the target node requested by the source node is not established.

[0217] The details of the indication of the rejection of the connection establishment by the target node in the communication rejection message sent by the relay node to the source node are described above in conjunction with the method 600. Therefore, repetition of the above details is omitted here.

[0218] Figure 8 The diagram shows some embodiments of the present disclosure. Figure 6 and Figure 7 The exemplary message sequence diagram corresponding to the method of relay connection between nodes. More specifically, Figure 8 The exemplary message sequence chart of FIG. 1 relates to 5G ProSe communication via 5G ProSe UE-to-UE relay using a direct link establishment procedure in case of failure / rejection by a target node (eg, a target 5G ProSe terminal UE).

[0219] Figure 8 Steps 1, 2, and 4 shown in Figure 5 Therefore, detailed explanation is omitted here to avoid repetition.

[0220] In step 3, the source 5G ProSe terminal UE sends a direct communication request message to initiate a link establishment procedure with the 5G ProSe UE to UE relay. Step 3 corresponds to sending a communication request message for establishing a connection to the target node via the relay node (i.e., Figure 6 Frame 610 and Figure 7 710).

[0221] For example, the direct communication request message may include a PROSE DIRECT LINK ESTABLISHMENT REQUEST message.

[0222] In response to receiving the direct communication request message, the 5G ProSe UE-to-UE relay sends a direct communication request message to initiate a link establishment procedure with the target 5G ProSe terminal UE (step 5). Using the direct communication request message sent in step 5, the relay node attempts to establish a connection to the target node (i.e., Figure 7 720).

[0223] For example, the direct communication request message may include a PROSE DIRECT LINK ESTABLISHMENT REQUEST message.

[0224] The link establishment procedure may fail due to a failure at the 5G ProSe terminal UE or rejection by the 5G ProSe terminal UE, and the target 5G ProSe terminal UE sends a direct communication rejection message to the 5G ProSe UE-to-UE relay. The direct communication rejection message includes an indication of the rejection by the target 5G ProSe terminal UE.

[0225] For example, a direct communication rejection message (e.g., a PROSE DIRECT LINK ESTABLISHMENT REJECT message) may include an information element for signaling a cause value, such as a PC5 signaling protocol cause IE. The PC5 signaling protocol cause IE may include a cause value (i.e., one or more cause values) indicating the rejection cause of the target 5G ProSe terminal UE (e.g., Figure 8 The value X shown in ).

[0226] In response to receiving the direct communication reject message from the target 5G ProSe terminal UE, the 5G ProSe UE-to-UE relay sends a direct communication reject message to the source 5G ProSe terminal UE (step 7). Step 7 corresponds to sending a communication reject message indicating the rejection of the connection establishment by the target node (i.e., Figure 6 Box 620 and Figure 7 The direct communication rejection message includes an indication of rejection by the target 5G ProSe terminal UE.

[0227] For example, the direct communication rejection message may include a PROSE DIRECT LINK ESTABLISHMENT REJECT message indicating a failure from the target 5G ProSe terminal UE. More specifically, the direct communication rejection message (e.g., the PROSE DIRECT LINK ESTABLISHMENT REJECT message) may include an information element for signaling a cause value for 5G ProSe UE-to-UE relay, such as an (existing) PC5 signaling protocol cause IE. The (existing) PC5 signaling protocol cause IE may be extended to provide an indication of the rejection by the target 5G ProSe terminal UE to the source 5G ProSe terminal UE. For example, the (existing) PC5 signaling protocol cause IE may indicate that the rejection is due to a failure or rejection from the target 5G ProSe terminal UE. Additionally, the direct communication rejection message (e.g., PROSE DIRECT LINK ESTABLISHMENT REJECT message) may further include a new PC5 signaling protocol cause IE (also referred to as PC5 UE failure cause IE) for signaling a cause value of the target 5G ProSe terminal UE. The new PC5 signaling protocol cause IE may be optional and is included if the (existing) PC5 signaling protocol cause IE indicates rejection by the target 5G ProSe terminal UE. The new PC5 signaling protocol cause IE may include one or more cause values ​​(e.g., Figure 8 The value X shown in ), is similar to the cause value indicating the rejection cause of 5G ProSe UE-to-UE relay.

[0228] In response to receiving the direct communication rejection message from the 5G ProSe UE to the UE relay, the source 5G ProSe terminal UE may decide on the next steps based on the rejection indication by the target 5G ProSe terminal UE (e.g., one or more cause values ​​provided in the existing PC5 signaling protocol cause IE and the new PC5 signaling protocol cause IE) (step 8). The next steps in step 8 may include the following: Figure 6 The process corresponding to box 630.

[0229] Figure 9 Illustrated is a method 900 of relaying connections between nodes according to some embodiments.

[0230] As described above, the method 900 is performed by a source node such as a user equipment (e.g., user equipment (UE)) or by an apparatus used in the source node (e.g., a source 5G ProSe terminal UE). As described above, the relay node and the target node can each be a user equipment (e.g., user equipment (UE)) or an apparatus used therein (e.g., a 5G ProSe UE-to-UE relay and a target 5G ProSe terminal UE, respectively).

[0231] In method 900, the source node has an established connection to the relay node (ie, an existing connection at the first hop). For example, the existing connection to the relay node may have been established as a result of performing methods 600 and 700 as described above.

[0232] At block 910, the source node sends a communication request message to the relay node for modifying an existing connection between the source node and the relay node to establish a connection to the target node. With the communication request message, the source node requests to modify the existing direct connection (i.e., the first hop) between the source node and the relay node and to establish a direct connection (i.e., the second hop) between the relay node and the target node, thereby establishing an (indirect) connection from the source node to the target node via the relay node.

[0233] In some examples, the communication request message for modifying an existing connection includes a PROSE DIRECT LINK MODIFICATION REQUEST message.

[0234] At block 920, the source node receives a communication rejection message from the relay node indicating a rejection of modifying the existing connection due to the rejection of the target node's rejection of establishing the connection. Using the communication rejection message, the relay node indicates to the source node, and thus informs the source node, that the target node refuses to establish a direct connection between the relay node and the target node. In other words, establishing the direct connection resulted in a failure or rejection, such that the second hop cannot be established.

[0235] In some examples, the communication rejection message indicating rejection of establishing the connection includes a PROSE DIRECT LINK MODIFICATION REJECT message.

[0236] Indication of refusal to modify an existing connection due to refusal by the target node to establish a connection in conjunction with the above Figure 6 The above-mentioned indication of the refusal of establishing a connection by the target node corresponds to the above-mentioned indication of the refusal of establishing a connection. Therefore, repetition of the details is omitted here.

[0237] In some examples, if the source node receives a communication rejection message indicating a rejection of modifying an existing connection due to a rejection of establishing a connection by the target node (block 920), the source node may perform a process(es) for handling or responding to the rejection by the target node (block 930). Figure 6 Block 630 describes .

[0238] Utilizing the method 900 described above, the source node is notified that the rejection is due to a rejection by the target node to establish a connection (ie, the second hop) between the relay node and the target node.

[0239] In some examples, the source device may attempt to connect or may be connected to multiple target nodes. In such an example, the communication rejection message indicating the rejection of the modification connection may include identification information indicating the target node among the multiple target nodes that caused the rejection. Based on the identification information, the source node may derive the target node that caused the rejection. That is, the source node may derive the identity of the target node. In some examples, the communication rejection message may include target terminal UE information indicating the user information ID of the target node (i.e., 5G ProSe terminal UE) when the rejection occurs in the first hop due to the rejection of establishing a connection on the second hop. This allows the source node to be guided to know which target node is refusing to establish a connection when the source node is trying to establish a connection with multiple target nodes.

[0240] Figure 10 Illustrated is a method 1000 of relaying connections between nodes according to some embodiments.

[0241] As described above, method 1000 is performed by a relay node such as a user equipment (e.g., user equipment (UE)) or by an apparatus used in a relay node (e.g., 5G ProSe UE-to-UE relay). As described above, the source node and the target node may each be a user equipment (e.g., user equipment (UE)) or an apparatus therefor (e.g., a source 5G ProSe terminal UE and a target 5G ProSe terminal UE, respectively).

[0242] In method 1000, the source node has an established connection to the relay node (ie, an existing connection at the first hop). For example, the existing connection to the relay node may have been established as a result of performing methods 600 and 700 as described above.

[0243] At block 1010, the relay node receives a communication request message from a source node for modifying an existing connection between the source node and the relay node to establish a connection to a target node. With the communication request message, the source node requests to modify the existing direct connection (i.e., the first hop) between the source node and the relay node and to establish a direct connection (i.e., the second hop) between the relay node and the target node, thereby establishing an (indirect) connection from the source node to the target node via the relay node.

[0244] In some examples, the communication request message for modifying an existing connection includes a PROSE DIRECT LINK MODIFICATION REQUEST message.

[0245] At block 1020, the relay node establishes or attempts to establish a connection to the target node (i.e., the second hop). More specifically, the relay node performs a process for establishing a connection to the target node. For example, the relay node may send a communication request message (e.g., a PROSE DIRECT LINK ESTABLISHMENT REQUEST message) for establishing a (direct) connection to the target node and receive a communication acceptance message (e.g., a PROSE DIRECT LINK ESTABLISHMENT ACCEPT message) from the target node to establish a connection between the relay node and the target node, or receive a communication rejection message (e.g., a PROSE DIRECT LINK ESTABLISHMENT REJECT message) from the target node indicating a rejection of the target node's request to establish the connection.

[0246] If the relay node receives a communication rejection message (i.e., a rejection of the establishment of a connection by the target node), the relay node sends a communication rejection message to the source node requesting to establish communication to the target node via the relay node, indicating a rejection of modifying the existing connection due to the rejection of the establishment of the connection by the target node (block 1030). Using the communication rejection message, the relay node indicates to the source node, and thus informs the source node, that the target node rejects the establishment of the second direct connection. In other words, the establishment of the second direct connection results in a failure or rejection, such that the second hop cannot be established.

[0247] In some examples, the communication rejection message indicating rejection of establishing the connection includes a PROSE DIRECT LINK MODIFICATION REJECT message.

[0248] Combined with the above Figure 6The method 600 describes details about the indication of rejection in the communication rejection message sent by the relay node to the source node. Therefore, repetition of the details is omitted here.

[0249] Figure 11 The diagram shows some embodiments of the present disclosure. Figure 9 and Figure 10 The exemplary message sequence diagram corresponding to the method of relay connection between nodes. More specifically, Figure 11 The exemplary message sequence chart relates to 5G ProSe communication via 5G ProSe UE-to-UE relay using a direct link modification procedure on the first hop in case of failure / rejection by a target node (e.g., a target 5G ProSe terminal UE).

[0250] The source 5G ProSe terminal UE and the 5G ProSe UE-to-UE relay have an (existing) connection, for example, resulting from performing the link establishment procedure as described above.

[0251] Figure 11 Steps 1 and 2 shown in Figure 5 Step 1 in corresponds to step 2. Therefore, detailed explanation is omitted here to avoid repetition.

[0252] In step 3, the source 5G ProSe terminal UE sends a direct modification request message to initiate a link modification procedure with the 5G ProSe UE to UE relay. That is, the source 5G ProSe terminal UE sends a direct modification request message to modify an existing connection. Step 3 corresponds to sending a communication request message for modifying an existing connection to the relay node to establish a connection to the target node (i.e., Figure 9 Frame 910 and Figure 10 1010).

[0253] For example, the direct modification request message may include a PROSE DIRECT LINK MODIFICATION REQUEST message.

[0254] In response to receiving the Direct Modify Request message, the 5G ProSe UE-to-UE relay sends a Direct Communication Request message to initiate a link establishment procedure with the target 5G ProSe terminal UE (step 4). Using the Direct Communication Request message, the relay node attempts to establish a connection to the target node (i.e., Figure 10 More specifically, the 5G ProSe UE-to-UE relay initiates a link establishment procedure to establish a connection with the target 5G ProSe terminal UE.

[0255] For example, the direct communication request message may include a PROSE DIRECT LINK ESTABLISHMENT REQUEST message.

[0256] Due to a failure at the target 5G ProSe terminal UE or a rejection by the target 5G ProSe terminal UE, the link establishment procedure may fail, and the target 5G ProSe terminal UE sends a direct communication reject message to the 5G ProSe UE-to-UE relay. The direct communication reject message includes an indication of the rejection by the target 5G ProSe terminal UE. For example, the direct communication reject message (e.g., PROSE DIRECT LINK ESTABLISHMENT REJECT message) may include an information element used to signal a cause value, such as a PC5 signaling protocol cause IE. The PC5 signaling protocol cause IE may include a cause value (i.e., one or more cause values) indicating the cause of the rejection by the target 5G ProSe terminal UE (e.g., Figure 11 The value X shown in ).

[0257] In response to receiving the direct communication reject message from the target 5G ProSe terminal UE, the 5G ProSe UE-to-UE relay sends a direct modification reject message to the source 5G ProSe terminal UE (step 6). Step 6 corresponds to sending a communication reject message indicating a rejection of modifying an existing connection due to a rejection of establishing a connection by the target node (i.e., Figure 9 The frame 920 and Figure 10 The directly modified rejection message includes an indication of rejection by the target 5G ProSe terminal UE.

[0258] For example, the direct modification reject message may include a PROSE DIRECT LINK MODIFICATION REJECT message indicating a failure from the target 5G ProSe terminal UE. More specifically, the direct modification reject message (e.g., the PROSE DIRECT LINK MODIFICATION REJECT message) may include an information element for signaling a cause value for the 5G ProSe UE-to-UE relay, such as an (existing) PC5 signaling protocol cause IE. The (existing) PC5 signaling protocol cause IE may be extended to provide an indication of the rejection by the target 5G ProSe terminal UE to the source 5G ProSe terminal UE. For example, the (existing) PC5 signaling protocol cause IE may indicate that the rejection is due to a failure or rejection from the target 5G ProSe terminal UE. Additionally, the direct communication rejection message (e.g., PROSE DIRECT LINK ESTABLISHMENT REJECT message) may further include a new PC5 signaling protocol cause IE (i.e., PC5 UE failure cause IE) for signaling a cause value of the target 5G ProSe terminal UE. The new PC5 signaling protocol cause IE may be optional and is included if the (existing) PC5 signaling protocol cause IE indicates rejection by the target 5G ProSe terminal UE. The new PC5 signaling protocol cause IE may include one or more cause values ​​(e.g., Figure 11 The value X shown in ), is similar to the cause value indicating the rejection cause of 5G ProSe UE-to-UE relay.

[0259] As described above, the direct modification rejection message may further include identification information indicating the target node (i.e., the target terminal UE information shown in step 6) to indicate the user information ID of the target 5G ProSe terminal UE among the multiple target 5G ProSe terminal UEs with which the source 5G ProSe terminal UE is attempting to perform 5G ProSe communication.

[0260] In response to receiving the direct modification rejection message from the 5G ProSe UE to the UE relay, the source 5G ProSe terminal UE may decide on the next steps (step 7) based on the rejection indication by the target 5G ProSe terminal UE (e.g., one or more cause values ​​provided in the existing PC5 signaling protocol cause IE and the new PC5 signaling protocol cause IE). The next steps in step 7 may include Figure 9 The process corresponding to box 930.

[0261] Figure 12 Illustrated is a method 1200 of relaying connections between nodes according to some embodiments.

[0262] As described above, the method 1200 is performed by a source node such as a user equipment (e.g., user equipment (UE)) or by an apparatus used in the source node (e.g., a source 5G ProSe terminal UE). As described above, the relay node and the target node can each be a user equipment (e.g., user equipment (UE)) or an apparatus used therein (e.g., a 5G ProSe UE-to-UE relay and a target 5G ProSe terminal UE, respectively).

[0263] In method 1200, the relay node has an established connection to the target node (ie, an existing connection at the second hop). For example, as a result of performing methods 600 and 700 as described above, the existing connection to the relay node may have been established.

[0264] At block 1210, the source node sends a communication request message to the relay node for establishing a connection to the target node by modifying the existing connection between the relay node and the target node. With the communication request message, the source node requests to establish a direct connection between the source node and the relay node (i.e., the first hop), and to modify the existing direct connection between the relay node and the target node (i.e., the second hop), thereby establishing an (indirect) connection from the source node to the target node via the relay node.

[0265] In some examples, the communication request message for establishing the connection includes a PROSE DIRECT LINK ESTABLISHMENT REQUEST message.

[0266] At block 1220, the source node receives a communication rejection message from the relay node indicating a rejection of establishing a connection between the source node and the relay node due to a rejection of modifying the existing connection between the relay node and the target node. Using the communication rejection message, the relay node indicates to the source node and notifies the source node that the target node refuses to modify the existing connection between the relay node and the target node. In other words, modifying the existing connection would result in a failure or rejection, such that the second hop cannot be modified.

[0267] In some examples, the communication rejection message indicating rejection of establishing the connection includes a PROSE DIRECT LINK ESTABLISHMENT REJECT message.

[0268] The indication of a refusal to establish a connection between the source node and the relay node due to a refusal to modify an existing connection between the relay node and the target node is combined with the above Figure 6The above-mentioned indication of the refusal of establishing a connection by the target node corresponds to the above-mentioned indication of the refusal of establishing a connection. Therefore, repetition of the details is omitted here.

[0269] In some examples, if the source node receives a communication rejection message indicating a rejection of establishing a connection between the source node and the relay node due to a rejection of modifying an existing connection between the relay node and the target node (block 1220), the source node may perform a process(es) for handling or responding to the rejection by the target node (block 1230). Figure 6 Block 630 of describes an example of such a process.

[0270] Utilizing the method 1200, the source node is notified that a rejection is due to a rejection by the target node to establish a connection (ie, the second hop) between the relay node and the target node.

[0271] Figure 13 Illustrated is a method 1300 of relaying connections between nodes according to some embodiments.

[0272] As described above, the method 1300 is performed by a relay node such as a user equipment (e.g., user equipment (UE)) or by an apparatus used in a relay node (e.g., 5G ProSe UE-to-UE relay). As described above, the source node and the target node may each be a user equipment (e.g., user equipment (UE)) or an apparatus therefor (e.g., a source 5G ProSe terminal UE and a target 5G ProSe terminal UE, respectively).

[0273] In method 1200, the relay node has an established connection to the target node (ie, an existing connection at the second hop). For example, as a result of performing methods 600 and 700 as described above, the existing connection to the relay node may have been established.

[0274] At block 1310, the relay node receives a communication request message from a source node for establishing a connection to the target node by modifying an existing connection between the relay node and the target node. With the communication request message, the source node requests to establish a direct connection between the source node and the relay node (i.e., a first hop), and modifies the existing direct connection between the relay node and the target node (i.e., a second hop), thereby establishing an (indirect) connection from the source node to the target node via the relay node.

[0275] In some examples, the communication request message for establishing the connection includes a PROSE DIRECT LINK ESTABLISHMENT REQUEST message.

[0276] At block 1320, the relay node modifies or attempts to modify an existing connection to the target node (i.e., the second hop). More specifically, the relay node performs a process for modifying the existing connection to the target node. For example, the relay node may send a communication request message (e.g., a PROSE DIRECTLINK MODIFICATION REQUEST message) to modify the existing connection to the target node and receive a communication accept message (e.g., a PROSE DIRECT LINK MODIFICATION ACCEPT message) from the target node to modify the existing connection between the relay node and the target node, or receive a communication reject message (e.g., a PROSE DIRECT LINK MODIFICATION REJECT message) from the target node indicating the target node's rejection of modifying the existing connection.

[0277] If the relay node receives a communication rejection message (i.e., a rejection by the target node to modify an existing connection), the relay node sends a communication rejection message to the source node requesting to establish communication to the target node via the relay node, indicating a rejection of establishing a connection between the source node and the relay node due to the rejection of modifying the existing connection between the relay node and the target node (block 1330). Using the communication rejection message, the relay node indicates to the source node and notifies the source node that the target node refuses to modify the existing direct connection. In other words, modifying the existing direct connection will result in a failure or rejection, so that the second hop cannot be modified.

[0278] In some examples, the communication rejection message indicating a rejection to establish a connection between the source node and the relay node due to a rejection to modify an existing connection between the relay node and the target node comprises a PROSE DIRECT LINK ESTABLISHMENT REJECT message.

[0279] Combined with the above Figure 6 The details of the indication of rejection in the communication rejection message have been described, and therefore, repetition of the details is omitted here.

[0280] In some examples, multiple source devices may attempt to connect or may be connected to the target node. In such an example, a communication rejection message indicating a rejection of establishing a connection between the source node and the relay node due to a rejection of modifying an existing connection between the relay node and the target node includes identification information of a source node among the multiple source devices indicating the request to establish a connection to the target node. Based on the identification information, the relay node can derive the source node that is attempting to connect to the target node and to which the communication rejection message is to be sent. That is, the source node can derive the identity of the target node. In some examples, the communication rejection message may include source terminal UE information indicating the user information ID of the source node (i.e., the source 5G ProSe terminal UE) when the rejection of the modification process occurs in the second hop. This allows the relay node to know which connection on the first hop (i.e., which source 5G ProSe terminal UE) is rejected when multiple source nodes are attempting to establish a connection with the same target node.

[0281] Figure 14 The diagram shows some embodiments of the present disclosure. Figure 12 and Figure 13 The exemplary message sequence diagram corresponding to the method of relay connection between nodes. More specifically, Figure 14 The exemplary message sequence chart relates to 5G ProSe communication via 5G ProSe UE-to-UE relay using a direct link modification procedure on the second hop in case of failure / rejection by a target node (e.g., a target 5G ProSe terminal UE).

[0282] The 5G ProSe UE-to-UE relay and the target 5G ProSe terminal UE have an (existing) connection, for example, resulting from performing the link establishment procedure as described above.

[0283] Figure 11 Steps 1 and 2 shown in Figure 5 , which corresponds to step 1 and step 2. Therefore, detailed explanation is omitted here to avoid repetition.

[0284] In step 3, the source 5G ProSe terminal UE sends a direct communication request message to initiate a link establishment procedure with the 5G ProSe UE to UE relay. Step 3 corresponds to sending a communication request message for establishing a connection to the relay node (i.e., Figure 12 Box 1210 and Figure 13 1310).

[0285] For example, the direct communication request message may include a PROSE DIRECT LINK ESTABLISHMENT REQUEST message.

[0286] In response to receiving the direct communication request message, the 5G ProSe UE-to-UE relay sends a direct modification request message to initiate a link modification procedure with the target 5G ProSe terminal UE (step 4). Using the direct modification request message, the relay node attempts to modify the existing connection to the target node (i.e., Figure 13 1320).

[0287] For example, the direct modification request message may include a PROSE DIRECT LINK MODIFICATION REQUEST message.

[0288] The link modification procedure may fail due to a failure at the target 5G ProSe terminal UE or a rejection by the target 5G ProSe terminal UE, and the target 5G ProSe terminal UE sends a direct modification reject message to the 5G ProSe UE-to-UE relay (step 5). The direct modification reject message includes an indication of the rejection by the target 5G ProSe terminal UE. For example, the direct modification reject message (e.g., PROSE DIRECT LINK MODIFICATION REJECT message) may include an information element used to signal a cause value, such as a PC5 signaling protocol cause IE. The PC5 signaling protocol cause IE may include a cause value (i.e., one or more cause values) indicating the cause of the rejection by the target 5G ProSe terminal UE (e.g., Figure 14 The value X shown in ).

[0289] As described above, the direct modification rejection message may further include identification information indicating the source node (i.e., the source terminal UE information shown in step 5) to indicate the user information ID of the source 5G ProSe terminal UE when multiple source 5G ProSe terminal UEs are attempting to perform 5G ProSe communication to the target 5G ProSe terminal UE.

[0290] In response to receiving the direct modification reject message from the target 5G ProSe terminal UE, the 5G ProSe UE-to-UE relay sends a direct communication reject message to the source 5G ProSe terminal UE (step 6). Step 6 corresponds to sending a communication reject message indicating a rejection of establishing a connection between the source node and the relay node due to a rejection of modifying the existing connection between the relay node and the target node (i.e., Figure 12 Box 1220 and Figure 13 The direct communication rejection message may include an indication of rejection by the target 5G ProSe terminal UE.

[0291] For example, the direct communication rejection message may include a PROSE DIRECT LINK ESTABLISHMENT REJECT message indicating a failure from the target 5G ProSe terminal UE. More specifically, the direct modification rejection message (e.g., the PROSE DIRECT LINK ESTABLISHMENT REJECT message) may include an (existing) PC5 signaling protocol cause IE for signaling a cause value for 5G ProSe UE-to-UE relay. The (existing) PC5 signaling protocol cause IE may be extended to provide an indication of the rejection by the target 5G ProSe terminal UE to the source 5G ProSe terminal UE. For example, the (existing) PC5 signaling protocol cause IE may indicate that the rejection is due to a failure or rejection from the target 5G ProSe terminal UE. Additionally, the direct communication rejection message (e.g., PROSE DIRECT LINK ESTABLISHMENT REJECT message) may further include a new PC5 signaling protocol cause IE (i.e., PC5 UE failure cause IE) for signaling a cause value of the target 5G ProSe terminal UE. The new PC5 signaling protocol cause IE may be optional and is included if the (existing) PC5 signaling protocol cause IE indicates rejection by the target 5G ProSe terminal UE. The new PC5 signaling protocol cause IE includes one or more cause values ​​(e.g., Figure 14 The value X shown in ), is similar to the cause value indicating the rejection cause of 5G ProSe UE-to-UE relay as described above.

[0292] In response to receiving the direct communication rejection message from the 5G ProSe UE to the UE relay, the source 5G ProSe terminal UE may decide on the next steps (step 7) based on the rejection indication by the target 5G ProSe terminal UE (e.g., one or more cause values ​​provided in the existing PC5 signaling protocol cause IE and the new PC5 signaling protocol cause IE). The next steps in step 7 may include Figure 12 The process corresponding to box 1230.

[0293] In some exemplary methods of relay connections between nodes as described above, a connection to a target node may be established via multiple relay nodes (i.e., more than one 5G ProSe UE-to-UE relay) (referred to herein as a multi-hop scenario). For example, the connections to be established include a first (direct) connection between a source node and a first relay node (e.g., a relay node as described above), a second (direct) connection between the first relay node and a second relay node, and a third (direct) connection between the second relay node and the target node. In order to establish a connection between the source node and the target node, if (multiple) (direct) connections between the nodes do not yet exist, they may be established; or if (multiple) (direct) connections between the nodes already exist, they may be modified. In order to provide the source node with an indication of which (intermediate) relay node rejected the establishment / modification of the connection, the communication rejection message received at the source node includes an indication of the (intermediate) relay node that caused the rejection of the connection to the target node. For example, the (existing) information element in the communication rejection message may include one or more reason values ​​indicating that the rejection was due to rejection by the (intermediate) relay node. Additionally or alternatively, the communication rejection message may comprise an additional information element for signaling one or more cause values ​​to the (intermediate) relay node.

[0294] Figure 15 An exemplary message sequence chart corresponding to a method for relaying a connection between nodes according to some embodiments of the present disclosure is illustrated. More specifically, Figure 15 The exemplary message sequence chart relates to the multi-hop scenario as described above in case of failure / rejection by the (intermediate) relay node (e.g., 5G ProSe UE to UE Relay 3).

[0295] like Figure 15 As shown in , a connection from a source node (ie, source 5G ProSe terminal UE) to a target node (ie, target 5G ProSe terminal UE) is established via multiple relay nodes (ie, 5G ProSe UE to UE Relays 1-3).

[0296] In step 1, the source 5G ProSe terminal UE sends a direct communication request message to initiate a link establishment process with the 5G ProSe UE to UE relay 1. The direct communication request message sent in step 1 is combined with the following Figure 6 Frame 610 and Figure 7 The communication request message for establishing a connection to the target node via the relay node corresponds to block 710 .

[0297] In response to receiving the direct communication request message, 5G ProSe UE-to-UE relay 1 sends a direct communication request message to initiate a link establishment procedure with 5G ProSe UE-to-UE relay 2 (step 2). In response to receiving the direct communication request message, 5G ProSe UE-to-UE relay 2 sends a direct communication request message to initiate a link establishment procedure with 5G ProSe UE-to-UE relay 3 (step 2). Using the direct communication request messages sent in steps 2 and 3, the relay nodes initiate a procedure for establishing a direct connection between relay nodes.

[0298] The link establishment procedure may fail due to a failure at the 5G ProSe UE-to-UE relay 3 or a rejection by the 5G ProSe UE-to-UE relay 3, and the 5G ProSe UE-to-UE relay 3 sends a direct communication reject message to the 5G ProSe UE-to-UE relay 2 (step 4). The direct communication reject message includes an indication of the rejection by the 5G ProSe UE-to-UE relay 3. For example, the direct communication reject message (e.g., PROSE DIRECT LINKESTABLISHMENT REJECT message) may include an information element used to signal a cause value, such as a PC5 signaling protocol cause IE. The PC5 signaling protocol cause IE may include a cause value (i.e., one or more cause values) indicating the cause of the rejection by the 5G ProSe UE-to-UE relay 3 (e.g., Figure 15 The value X shown in ).

[0299] In response to receiving the direct communication rejection message from the 5G ProSe UE to UE relay 3, the 5G ProSe UE to UE relay 2 may decide the next steps (step 4a) based on the rejection indication by the 5G ProSe UE to UE relay 3 (e.g., one or more cause values ​​provided in the existing PC5 signaling protocol cause IE and the intermediate PC5 signaling protocol cause IE). Examples of the next steps in step 4a may include the above reference Figure 6 For example, the 5G ProSe UE-to-UE relay 2 may decide to find another 5G ProSe UE-to-UE relay and retry to establish a connection to the other 5G ProSe UE-to-UE relay 3.

[0300] In response to receiving the direct communication rejection message from the 5G ProSe UE-to-UE relay 3, the 5G ProSe UE-to-UE relay 2 sends a direct communication rejection message to the 5G ProSe UE-to-UE relay 1 (step 5). The direct communication rejection message includes an indication of rejection by the 5G ProSe UE-to-UE relay 3. In other words, the 5G ProSe UE-to-UE relay 2 propagates the indication of rejection by the 5G ProSe UE-to-UE relay 3 to the 5G ProSe UE-to-UE relay 1.

[0301] For example, the direct communication rejection message may include a PROSE DIRECT LINK ESTABLISHMENT REJECT message indicating a failure from the 5G ProSe UE to the UE relay 3. More specifically, the direct modification rejection message (e.g., the PROSE DIRECT LINK ESTABLISHMENT REJECT message) may include an information element for signaling a cause value for the 5G ProSe UE to UE relay, such as an (existing) PC5 signaling protocol cause IE. The (existing) PC5 signaling protocol cause IE may be extended to provide an indication of the rejection by the 5G ProSe UE to the UE relay 3. For example, the (existing) PC5 signaling protocol cause IE may indicate that the rejection is due to a failure or rejection from the 5G ProSe UE to the UE relay 3 (i.e., a failure in the UE to UE relay). Additionally, the direct communication rejection message (e.g., PROSE DIRECT LINK ESTABLISHMENT REJECT message) may further include a new PC5 signaling protocol cause IE (i.e., intermediate PC5 signaling protocol cause IE) for signaling a cause value for the (intermediate) 5G ProSe UE to UE relay (such as 5G ProSe UE to UE relay 3). The new PC5 signaling protocol cause IE may be optional and is included if the (existing) PC5 signaling protocol cause IE indicates rejection by the (intermediate) 5G ProSe UE to UE relay 3. The new PC5 signaling protocol cause IE may include one or more cause values ​​(e.g., Figure 15 The value X shown in ), is similar to the cause value indicating the rejection cause of 5G ProSe UE-to-UE relay.

[0302] In some examples, the direct communication rejection message may also include identification information indicating the relay node (i.e., relay UE information) to indicate the user information ID of the (intermediate) 5G ProSe UE to UE relay 3 among the multiple 5G ProSe UE to UE relays involved in the relay connection from the source 5G ProSe terminal UE relay to the target 5G ProSe terminal UE.

[0303] In response to receiving the direct communication rejection message from the 5G ProSe UE-to-UE Relay 2, the 5G ProSe UE-to-UE Relay 1 sends a direct communication rejection message to the source 5G ProSe terminal UE (step 6). The direct communication rejection message includes an indication of rejection by the 5G ProSe UE-to-UE Relay 3. In other words, the 5G ProSe UE-to-UE Relay 1 propagates the indication of rejection by the 5G ProSe UE-to-UE Relay 3 to the source 5G ProSe terminal UE.

[0304] In response to receiving the direct communication rejection message from the 5G ProSe UE to the UE relay 1, the source 5G ProSe terminal UE may decide the next steps (step 7) based on the rejection indication by the 5G ProSe UE to the UE relay 3 (e.g., one or more cause values ​​provided in the existing PC5 signaling protocol cause IE and the intermediate PC5 signaling protocol cause IE). The next steps in step 7 may include the steps described above with reference to Figure 6 The process described in box 630 of .

[0305] It should be understood that Figure 15 In the exemplary message sequence chart of , (multiple) existing connections between the nodes may exist, so that a process for modifying such existing connections may be performed instead of establishing a (new) connection.

[0306] It should be understood that these devices may include or be coupled to other units or modules used in / for transmission and / or reception, such as radio components or radio heads. Although these devices are described as one entity, different modules and memories may be implemented in one or more physical or logical entities.

[0307] Note that while the embodiments have been described with respect to LTE and 5G NR, similar principles can also be applied to other networks and communication systems that require forced fast connection reestablishment. Thus, while certain embodiments have been described above by way of example with reference to certain example architectures for wireless networks, technologies, and standards, the embodiments can be applied to any other suitable form of communication system other than those shown and described herein.

[0308] It is also noted herein that while the above describes exemplary embodiments, there are numerous variations and modifications which may be made to the disclosed solution without departing from the scope of the present disclosure.

[0309] In general, various exemplary embodiments may be implemented in hardware or dedicated circuitry, software, logic, or any combination thereof. Some aspects of the present disclosure may be implemented in hardware, while other aspects may be implemented in firmware or software, which may be executed by a controller, microprocessor, or other computing device, although the present disclosure is not limited thereto. Although various aspects of the present disclosure may be shown and described as block diagrams, flow charts, or using some other graphical representation, it is well understood that, as non-limiting examples, the blocks, devices, systems, techniques, or methods described herein may be implemented in hardware, software, firmware, dedicated circuitry or logic, general-purpose hardware or a controller or other computing device, or some combination thereof.

[0310] The example embodiments of the present disclosure may be implemented by computer software executable by a data processor of a mobile device (such as in a processor entity), or by hardware, or by a combination of software and hardware. Computer software or programs (also referred to as program products, including software routines, applets and / or macros) may be stored in a data storage medium readable by any device, and they include program instructions for performing specific tasks. A computer program product may include one or more computer executable components that are configured to perform an embodiment when the program is running. One or more computer executable components may be at least one software code or a portion thereof.

[0311] In addition, it should be noted in this respect that any block of the logic flow as shown in the figure can represent a program step, or interconnected logic circuits, blocks and functions, or a combination of program steps and logic circuits, blocks and functions. The software can be stored on a physical medium such as a memory chip or a memory block implemented in a processor, a magnetic medium (such as a hard disk or a floppy disk), and an optical medium (such as a DVD and its data variant CD). Physical media is a non-transient medium.

[0312] The memory may be of any type suitable for the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and removable memory. The data processor may be of any type suitable for the local technical environment, and may include, by way of non-limiting example, one or more of the following: a general-purpose computer, a special-purpose computer, a microprocessor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), an FPGA, a gate-level circuit, and a processor based on a multi-core processor architecture.

[0313] Example embodiments of the present disclosure can be practiced in various components such as integrated circuit modules. The design of integrated circuits is generally a highly automated process. Complex and powerful software tools are available to convert logic-level designs into semiconductor circuit designs for etching and formation on semiconductor substrates.

[0314] The foregoing description has provided by way of non-limiting examples a complete and informative description of exemplary embodiments of the present disclosure. However, various modifications and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description when read in conjunction with the accompanying drawings and the appended claims. Nevertheless, all such and similar modifications of the teachings of this invention will still fall within the scope of the present disclosure as defined in the appended claims. Indeed, additional embodiments exist including combinations of one or more embodiments with any other embodiments previously discussed.

Claims

1. A method for relaying a connection between nodes, comprising: - sending a communication request message from the source node to the relay node for establishing a connection to the target node via the relay node; as well as - receiving, at the source node, a communication rejection message from the relay node, the communication rejection message indicating a rejection by the target node of establishing the connection; wherein the communication rejection message includes: one or more reason values ​​indicating that the rejection is due to rejection by the target node; and The communication rejection message includes an additional information element for signaling a cause value to the target node.

2. A method for relaying connections between nodes, comprising: - receiving, at a relay node, a communication request message from a source node for establishing a connection to a target node via the relay node; - establishing said connection to said target node; as well as - in response to receiving a refusal by the destination node to establish the connection, sending a communication refusal message from the relay node to the source node, the communication refusal message indicating the refusal by the destination node to establish the connection; wherein the communication rejection message includes: one or more reason values ​​indicating that the rejection is due to rejection by the target node; and The communication rejection message includes an additional information element for signaling a cause value to the target node.

3. A device in a source node, comprising: at least one processor; as well as at least one memory comprising computer program code, wherein the computer program code, when executed by the at least one processor, causes the apparatus to: - sending a communication request message to a relay node for establishing a connection to a target node via said relay node; and - receiving a communication rejection message from the relay node, the communication rejection message indicating a rejection by the target node of establishing the connection; wherein the communication rejection message includes: one or more reason values ​​indicating that the rejection is due to rejection by the target node; and The communication rejection message includes an additional information element for signaling a cause value to the target node.

4. The apparatus of claim 3 , wherein the computer program code, when executed by the at least one processor, further causes the apparatus to: - in response to receiving the communication rejection message, retrying to establish the connection to the target node by sending to the relay node another communication request message for establishing the connection to the target node via the relay node.

5. The apparatus of claim 4 , wherein the computer program code, when executed by the at least one processor, further causes the apparatus to: - in response to receiving the communication rejection message, starting a timer; and - in response to expiry of said timer, sending said further communication request message.

6. The apparatus according to any one of claims 3 to 5, wherein the computer program code, when executed by the at least one processor, further causes the apparatus to: - in response to receiving the communication rejection message, performing a relay reselection process to select another relay node; and - sending a communication request message to the further relay node for establishing the connection to the target node via the further relay node.

7. The apparatus according to any one of claims 3 to 6, wherein the computer program code, when executed by the at least one processor, further causes the apparatus to: - in response to receiving the communication rejection message, determining whether the rejection by the target node is permanent; and - in response to determining that the rejection is permanent, performing a discovery process to discover another target with which to establish the connection via the relay node or another relay node.

8. The apparatus according to any one of claims 3 to 7, wherein the computer program code, when executed by the at least one processor, further causes the apparatus to: - sending a communication request message to the relay node, the communication request message being used to modify an existing connection to the relay node to establish the connection to the target node; and - receiving a communication rejection message from the relay node, the communication rejection message indicating a rejection of modifying the existing connection due to a rejection of establishing the connection by the target node.

9. The apparatus according to any one of claims 3 to 7, wherein the computer program code, when executed by the at least one processor, further causes the apparatus to: - sending a communication request message to the relay node, the communication request message being used to establish the connection to the target node by modifying the existing connection between the relay node and the target node; and - receiving a communication rejection message from the relay node, the communication rejection message indicating a rejection of establishing the connection between the source node and the relay node due to a rejection of modifying the existing connection between the relay node and the target node.

10. The apparatus of claim 8 or 9, wherein the communication rejection message indicating the rejection of modifying the connection comprises: Indicates identification information of the source node and / or indicates identification information of the target node.

11. The apparatus of claim 10, wherein the computer program code, when executed by the at least one processor, further causes the apparatus to: - deriving the target node from a plurality of target nodes to which the source node is attempting to connect based on the identification information indicating the target node.

12. The apparatus according to any one of claims 8 to 11, wherein the communication request message for modifying the connection comprises: The Proximity Service (PROSE) Direct Link Modify Request message, and / or the communication reject message indicating the rejection of modifying the connection comprises a PROSE Direct Link Modify Reject message.

13. The apparatus according to any one of claims 3 to 12, wherein the communication rejection message indicates a rejection by the source node of one or more second relay nodes via which the source node is to connect to the destination node.

14. The apparatus according to claim 13, wherein the communication rejection message comprises: One or more reason values ​​indicating that the rejection is due to rejection by a second relay node of the one or more second relay nodes.

15. The apparatus according to claim 14, wherein the communication rejection message comprises: An additional information element for signaling a cause value to the second relay node.

16. A device in a relay node, comprising: at least one processor; as well as at least one memory comprising computer program code, wherein the computer program code, when executed by the at least one processor, causes the apparatus to: - receiving a communication request message from a source node for establishing a connection to a target node via the relay node; - establishing said connection to said target node; as well as - in response to receiving a refusal by the target node to establish the connection, sending a communication refusal message to the source node, the communication refusal message indicating the refusal by the target node to establish the connection; wherein the communication rejection message includes: one or more reason values ​​indicating that the rejection is due to rejection by the target node; and The communication rejection message includes an additional information element for signaling a cause value to the target node.

17. The apparatus of claim 16, wherein the computer program code, when executed by the at least one processor, further causes the apparatus to: - receiving a communication request message from the source node, the communication request message being used to modify an existing connection to the relay node in order to establish the connection to the target node; - in response to receiving a refusal by the target node to establish the connection, sending a communication refusal message to the source node, the communication refusal message indicating a refusal to modify the existing connection due to the refusal by the target node to establish the connection.

18. The apparatus of claim 16, wherein the computer program code, when executed by the at least one processor, further causes the apparatus to: - receiving a communication request message from the source node, the communication request message being used to establish the connection to the target node by modifying an existing connection between the relay node and the target node; and - sending a communication rejection message to the source node, the communication rejection message indicating a rejection of establishing the connection between the source node and the relay node due to a rejection of modifying the existing connection between the relay node and the target node.

19. The apparatus of claim 16 or 17, wherein the communication rejection message indicating the rejection of modifying the connection comprises: Indicates identification information of the source node and / or indicates identification information of the target node.

20. The apparatus of claim 19, wherein the computer program code, when executed by the at least one processor, further causes the apparatus to: - deriving the source node from a plurality of source nodes that are attempting to connect to the target node based on the identification information indicating the source node.

21. The apparatus according to any one of claims 16 to 20, wherein the communication rejection message indicates a rejection by the source node of one or more second relay nodes via which to connect to the destination node.

22. The apparatus according to claim 21, wherein the communication rejection message comprises: One or more reason values ​​indicating that the rejection is due to rejection by a second relay node of the one or more second relay nodes.

23. The apparatus of claim 22, wherein the communication rejection message comprises: An additional information element for signaling a cause value to the second relay node.

24. The apparatus according to any one of claims 21 to 23, wherein the computer program code, when executed by the at least one processor, further causes the apparatus to: - in response to receiving said rejection by one or more second relay nodes, performing a relay reselection procedure to select another second relay node; and - establishing said connection to said target node via said further second relay node.

25. A computer program product comprising program instructions stored on a computer-readable medium for performing the method according to any one of claims 1 to 2 when the program is executed on a computer.

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