Method and apparatus for relayed connections between nodes - Patents.com

Abstract

Techniques for a relayed connection between nodes are provided. For example, a method for a relayed connection between nodes includes sending a communication request message from a source node to a relay node to establish a connection to a target node via the relay node, and receiving a communication refusal message from the relay node at the source node indicating a refusal by the target node to establish the connection.

Description

[Technical Field]

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

[0002] Wireless telecommunication systems are continuously developing. Higher data rates and higher quality of service are required. Reliability requirements are constantly increasing, and methods and means are continuously being developed to ensure reliable connections and data traffic while minimizing transmission delays.

[0003] Standardization organizations such as the Third Generation Partnership Project (3GPP) are examining potential solutions for efficient operation of radio communications in new radio (NR) networks. 5G / NR, the next generation mobile radio communication system, will support various use cases and various deployment scenarios. In addition to typical mobile broadband use cases, NR is also being developed to support Machine Type Communication (MTC), Ultra Reliable Low Latency Communication (URLCC), sidelink device-to-device communication (D2D), and other use cases. Summary of the Invention [Problem to be solved by the invention]

[0004] It is an object of the present disclosure to improve direct communication services by providing a mechanism that facilitates improved relayed connections between nodes in a network. A method and apparatus for relayed connections between nodes for improving direct communication services are provided. [Means for solving the problem]

[0005] According to a first aspect of the present disclosure, there is provided a method for a relayed connection between nodes, the method including: 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 a communication rejection message from the relay node at the source node indicating a rejection of the establishment of the connection 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 establishment of the 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 starting a timer in response to receiving the communication rejection message, and sending another communication request message in response to the timer elapses.

[0008] In some examples of the first aspect, the method further includes, in response to receiving the communication rejection message, performing a relay reselection procedure to select another relay node, and sending a communication request message from the source node to the other relay node to establish 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 procedure to discover another target node with which to establish a connection via the relay node or another relay node.

[0010] In some examples of the first aspect, the method further includes sending a communication request message from the source node to the relay node to modify 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 the modification of the existing connection due to a rejection by the target node of the establishment of the connection.

[0011] In some examples of the first aspect, the method further includes sending a communication request message from the source node to the relay node to establish a connection to the target node by modifying an existing connection between the relay node and the target node, and receiving a communication rejection message at the source node from the relay node indicating a rejection to the establishment of the connection between the source node and the relay node due to the rejection to the modification of the existing connection between the relay node and the target node.

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

[0013] In some examples of the first aspect, the method further includes deriving, among the multiple target nodes, a target node to which the source node is attempting a connection that is causing the rejection, based on identification information indicating the target node.

[0014] In some examples of the first aspect, the communication request message to modify the connection includes a PROSE DIRECT LINK MODIFICATION REQUEST message, and / or the communication rejection message indicating a rejection to the modification of 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 cause values ​​indicating that the rejection is due to a 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 for signaling a cause value of a relay node in a communication rejection message.

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

[0018] In some examples of the first aspect, the communication request message to establish the connection includes a PROSE DIRECT LINK ESTABLISHMENT REQUEST message, and / or the communication rejection message indicating a rejection to the establishment of 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 one or more second relay nodes through which the source node connects 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 a second relay node among 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 for signaling a cause value of a relay node in a communication rejection message.

[0022] In some examples of the first aspect, the communication rejection message includes an additional information element for signaling a cause value of 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, there is provided a method for a relay connection between nodes, the method including: transmitting a communication request message from a source node to a relay node to modify an existing connection to the relay node to establish a connection to a target node through the relay node; and receiving a communication rejection message from the relay node at the source node indicating a rejection of the modification of the existing connection due to a rejection by the target node of the establishment of the connection.

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

[0026] According to a third aspect of the present disclosure, there is provided a method for a relay connection between nodes, the method including: transmitting, from a source node to a relay node, a communication request message for establishing a connection to a target node through 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 a rejection of the establishment of the connection between the source node and the relay node due to a rejection of the modification of 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 of the examples of the method according to the first aspect outlined above.

[0028] According to a fourth aspect of the present disclosure, there is provided a method for a relayed connection between nodes, the method including: receiving, at a relay node from a source node, a communication request message for establishing a connection to a target node via the relay node, establishing the connection to the target node, and, in response to receiving a refusal by the target node to establish the connection, transmitting a communication refusal message from the relay node to the source node indicating the refusal by the target node to establish the connection.

[0029] In some examples of the third aspect, the method further includes receiving, at the relay node from the source node, a communication request message to modify an existing connection to the relay node and establish a connection to the target node, and in response to receiving a refusal by the target node to establish the connection, transmitting a communication refusal message from the relay node to the source node indicating a refusal to modify the existing connection due to the refusal by the target node to establish the connection.

[0030] In some examples of the third aspect, the method further includes receiving, at a relay node from the source node, a communication request message to establish a connection to the target node by modifying an existing connection between the relay node and the target node, and transmitting, from the relay node to the source node, a communication rejection message indicating a rejection to the establishment of the connection between the source node and the relay node due to the rejection to the modification of the existing connection between the relay node and the target node.

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

[0032] In some examples of the third aspect, the method further includes deriving a source node causing the rejection among multiple 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 to modify the connection includes a PROSE DIRECT LINK MODIFICATION REQUEST message, and / or the communication rejection message indicating a rejection to the modification of 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 cause values ​​indicating that the rejection is due to a 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 for signaling a cause value of a relay node in a communication rejection message.

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

[0037] In some examples of the third aspect, the communication request message to establish the connection includes a PROSE DIRECT LINK ESTABLISHMENT REQUEST message, and / or the communication rejection message indicating a rejection to the establishment of 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 one or more second relay nodes through which the source node connects to the target node.

[0039] In some examples of the third aspect, the communication rejection message includes one or more cause values ​​indicating that the rejection is due to a rejection by a second relay node among 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 for signaling a cause value of a relay node in a communication rejection message.

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

[0042] In some examples of the third aspect, the method further includes, in response to receiving a rejection by the one or more second relay nodes, performing a relay reselection procedure 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, there is provided a method for a relayed connection between nodes, the method including: receiving, at a relay node from a source node, a communication request message to modify an existing connection to the relay node and establish a connection to a target node through the relay node; establishing the connection to the target node; and, in response to receiving a refusal by the target node to establish the connection, transmitting a communication refusal message from the relay node to the source node indicating a refusal to modify the existing connection due to the refusal by the target node to establish the connection.

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

[0046] According to a sixth aspect of the present disclosure, there is provided a method for a relayed connection between nodes, the method including: receiving, at a relay node from a source node, a communication request message for establishing a connection to a target node through the relay node by modifying an existing connection between the relay node and the target node, establishing the connection to the target node, and, in response to receiving a refusal to establish the connection by the target node, transmitting a communication refusal message from the relay node to the source node indicating a refusal to establish the connection between the source node and the relay node due to the refusal to modify 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 of the examples of the method according to the fourth aspect outlined above.

[0048] According to a seventh aspect of the present disclosure, a method for a relayed 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 target node via the first relay node, establishing the connection to the target node, and, in response to receiving a refusal by the target node to establish the connection, transmitting a communication refusal message from the first relay node to the second relay node indicating the refusal by the target node to establish the connection. Optionally, in some examples, the connection to the target 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 of the examples of the method according to the fourth aspect outlined above.

[0050] According to an eighth aspect of the present disclosure, a method for a relayed 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 target node through the first relay node; establishing the connection to the target node; and, in response to receiving a refusal by the target node to establish the connection, transmitting a communication refusal message from the second relay node to the first relay node indicating a refusal to modify the existing connection due to the refusal by the target node to establish the connection. Optionally, in some examples, the connection to the target 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 of the examples of the method according to the fourth aspect outlined above.

[0052] According to a ninth aspect of the present disclosure, a method for a relay 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 target node through 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 refusal by the target node to modify the existing connection, transmitting a communication refusal message from the first relay node to the second relay node indicating a refusal to establish the connection from the source node to the target node due to the refusal to modify the existing connection between the first relay node and the target node. Optionally, in some examples, the (existing) connection to the target node may be established via one or more additional relay nodes.

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

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

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

[0056] In some examples of the tenth embodiment, the computer program code, when executed on at least one processor, further causes the device or source node to start a timer in response to receiving the communication rejection message, and to send another communication request message in response to the timer elapses.

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

[0058] In some examples of the tenth embodiment, the computer program code, when executed on at least one processor, further causes the device or source node, in response to receiving the communication refusal message, to determine whether the refusal by the target node is permanent, and, in response to determining that the refusal is permanent, to perform a discovery procedure to discover another target with which to establish a connection via the relay node or another relay node.

[0059] In some examples of the tenth aspect, the computer program code, when executed by at least one processor, further causes the device or source node to send a communication request message to the relay node to modify an existing connection to the relay node and establish a connection to the target node, and receive a communication refusal message from the relay node indicating a refusal to modify the existing connection due to the target node's refusal to establish the connection.

[0060] In some examples of the tenth aspect, the computer program code, when executed on at least one processor, further causes the device or source node to send a communication request message to the relay node to establish a connection to the target 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 to establishing a connection between the source node and the relay node due to a rejection to modify the existing connection between the relay node and the target node.

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

[0062] In some examples of the tenth aspect, the computer program code, when executed on at least one processor, further causes the device or the source node to derive, among multiple target nodes, a target node to which the source node is attempting a connection that is causing the rejection, based on the identification information indicating the target node.

[0063] In some examples of the tenth aspect, the communication request message to modify the connection includes a PROSE DIRECT LINK MODIFICATION REQUEST message, and / or the communication rejection message indicating a rejection to the modification of 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 cause values ​​indicating that the rejection is due to a 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 for signaling a cause value of the relay node in the communication rejection message.

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

[0067] In some examples of the tenth aspect, the communication request message to establish the connection includes a PROSE DIRECT LINK ESTABLISHMENT REQUEST message, and / or the communication rejection message indicating a rejection to the establishment of 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 one or more second relay nodes through which the source node connects to the target node.

[0069] In some examples of the tenth aspect, the communication rejection message includes one or more cause values ​​indicating that the rejection is due to a rejection by a second relay node among 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 for signaling a cause value of the relay node in the communication rejection message.

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

[0072] According to an eleventh aspect of the present disclosure, there is provided a source node (e.g., a source user device or user equipment (UE)) or an apparatus at such a source node. The source node or apparatus according to the eleventh aspect comprises at least one processor and at least one memory containing computer program code. The computer program code, when executed on the at least one processor, causes the source node or apparatus to send a communication request message to the relay node to modify an existing connection to the relay node and establish a connection to a target node via the relay node, and to receive a communication rejection message from the relay node indicating a rejection of the modification of the existing connection due to the target node's refusal to establish the connection.

[0073] In some examples, the computer program code, when executed by at least one processor, causes a source node or device according to the eleventh aspect to perform one or more of the example methods according to the first aspect outlined above.

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

[0075] In some examples, the computer program code, when executed on at least one processor, causes a source node or device according to the twelfth aspect to perform one or more of the example methods according to the first aspect outlined above.

[0076] According to a thirteenth aspect of the present disclosure, there is provided a relay node (e.g., a relay user device or user equipment (UE)) or an apparatus in such a relay node. The relay node or apparatus according to the thirteenth aspect comprises at least one processor and at least one memory containing computer program code. The computer program code, when executed on 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 the connection to the target node, and, in response to receiving a refusal by the target node to establish the connection, send a communication rejection message to the source node indicating the refusal by the target node to establish the connection.

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

[0078] In some examples of the thirteenth aspect, the computer program code, when executed on at least one processor, causes an apparatus or a relay node to receive a communication request message from a source node to establish a connection to the 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 to the establishment of the connection between the source node and the relay node due to the rejection to the modification of the existing connection between the relay node and the target node.

[0079] In some examples of the thirteenth aspect, the communication refusal message indicating a refusal to modify 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 on at least one processor, further causes the device or relay node to derive a source node causing the rejection among 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 to modify the connection includes a PROSE DIRECT LINK MODIFICATION REQUEST message, and / or the communication rejection message indicating a rejection to the modification of 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 cause values ​​indicating that the rejection is due to a 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 for signaling a cause value of the relay node in the communication rejection message.

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

[0085] In some examples of the thirteenth aspect, the communication request message to establish the connection includes a PROSE DIRECT LINK ESTABLISHMENT REQUEST message, and / or the communication rejection message indicating a rejection to the establishment of 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 one or more second relay nodes through which the source node connects 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 a rejection by a second relay node among 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 for signaling a cause value of the relay node in the communication rejection message.

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

[0090] In some examples of the thirteenth aspect, the computer program code, when executed on at least one processor, further causes the device or relay node, in response to receiving a rejection by one or more second relay nodes, to perform a relay reselection procedure 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, there is provided a relay node (e.g., a relay user device or user equipment (UE)) or an apparatus in such a relay node. The relay node or apparatus according to the fourteenth aspect comprises at least one processor and at least one memory including computer program code. The computer program code, when executed on the at least one processor, 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, establish the connection to the target node, and, in response to receiving a refusal by the target node to establish the connection, transmit a communication refusal message to the other relay node indicating a refusal by the target node to establish the connection. 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 on at least one processor, causes a relay node or apparatus according to the fourteenth aspect to perform one or more of the example methods according to the fourth aspect outlined above.

[0093] According to a fifteenth aspect of the present disclosure, there is provided a relay node (e.g., a relay user device or user equipment (UE)) or an apparatus in such a relay node. The relay node or apparatus according to the fifteenth aspect comprises at least one processor and at least one memory including computer program code. The computer program code, when executed on the at least one processor, causes the relay node or apparatus to: receive a communication request message from another relay node to modify an existing connection to the relay node to establish a connection from the source node to a target node via the relay node; establish the connection to the target node; and, in response to receiving a refusal to establish the connection by the target node, transmit a communication refusal message to the other relay node indicating a refusal to modify the existing connection due to the refusal to establish 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 on at least one processor, causes a relay node or apparatus according to the fifteenth aspect to perform one or more of the example methods according to the fourth aspect outlined above.

[0095] According to a sixteenth aspect of the present disclosure, a relay node (e.g., a relay user device or user equipment (UE)) or an apparatus in such a relay node is provided. The relay node or apparatus according to the sixteenth aspect comprises at least one processor and at least one memory including computer program code. When executed on the at least one processor, the computer program code 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 refusal by the target node to modify the existing connection, transmit a communication refusal message to the other relay node indicating a refusal to establish the connection from the source node to the target node due to the refusal to modify the existing connection between the relay node and the target node. Optionally, in some examples, the (existing) connection to the target node may be established via one or more additional relay nodes.

[0096] In some examples, the computer program code, when executed on at least one processor, causes a relay node or apparatus according to the sixteenth aspect to perform one or more of the example methods according to the fourth aspect outlined above.

[0097] According to a seventeenth aspect of the present disclosure, there is provided a source node (e.g., a source user device or user equipment (UE)) or an apparatus in such a source node, comprising: means (a transmitting module) for transmitting a communication request message to a relay node to establish a connection to a target node via the relay node; and means (a receiving module) for receiving a communication rejection message from the relay node indicating a rejection of the establishment of the connection by the target node.

[0098] In some examples of the seventeenth aspect, the source node or apparatus further comprises means or modules for performing one or more of the examples according to the first aspect.

[0099] According to an eighteenth aspect of the present disclosure, there is provided a source node (e.g., a source user device or user equipment (UE)) or an apparatus in such a source node, comprising: means (a transmitting module) for transmitting a communication request message to a relay node to modify an existing connection to the relay node and establish a connection to a target node via the relay node; and means (a receiving module) for receiving a communication rejection message from the relay node indicating a rejection of the modification of the existing connection due to the target node's rejection of the establishment of the connection.

[0100] In some examples of the eighteenth aspect, the source node or apparatus further comprises means or modules for performing one or more of the examples according to the first aspect.

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

[0102] In some examples of the nineteenth aspect, the source node or apparatus further comprises means or modules for performing one or more of the examples according to the first aspect.

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

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

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

[0106] In some examples of the twenty-first aspect, the relay node or apparatus further comprises means or modules for performing one or more of the examples according to the fourth aspect.

[0107] According to a twenty-second aspect of the present disclosure, there is provided a relay node (e.g., a relay user device or user equipment (UE)) or an apparatus in such a relay node. The relay node or apparatus according to the twenty-second aspect includes: means (a receiving module) 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, and receiving a communication request message for establishing the connection to the target node from another relay node; and means (a transmitting module) for transmitting, in response to receiving a refusal by the target node to establish the connection, to another relay node, a communication refusal message indicating a refusal to modify the existing connection due to the target node's refusal to establish the connection.

[0108] In some examples of the twenty-second aspect, the relay node or apparatus further comprises means or modules for performing one or more of the examples according to the fourth aspect.

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

[0110] In some examples of the twenty-third aspect, the relay node or apparatus further comprises means or modules for performing one or more of the examples according to the fourth aspect.

[0111] According to a twenty-fourth aspect of the present disclosure, a computer program product includes program instructions stored on a computer-readable medium, which, when said program is executed on a computer, performs steps according to any one of the example methods according to the first to ninth aspects outlined above.

[0112] According to a twenty-fifth aspect of the present disclosure, a non-transitory computer-readable medium contains computer-executable instructions that, when executed on one or more processors, perform steps according to any one of the example methods according to the first to ninth aspects outlined above.

[0113] The above aspects and features may be implemented in a system, apparatus, method, article, and / or non-transitory computer-readable medium, depending on the desired configuration. The present disclosure may be implemented in and / or used with many different types of devices, including, but not limited to, mobile 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 of the aspects and features according to the present disclosure. Accordingly, it will be understood that the above-described features are merely examples and should not be construed to narrow 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, drawings, and claims.

[0115] The present disclosure can be better understood from the following detailed description of various embodiments when considered in conjunction with the following drawings. [Brief explanation of the drawings]

[0116] [Figure 1] 1 is a schematic diagram of an example wireless network. [Figure 2] 1 is a schematic diagram of an example wireless device. [Figure 3] FIG. 1 is a schematic diagram of an example network node. [Figure 4] FIG. 1 illustrates an exemplary reference architecture described in 3GPP TS 23.304, Release 18. [Figure 5] FIG. 1 is a diagram illustrating an example of a procedure for 5G ProSe Communication via 5G ProSe UE-to-UE Relay, as described in 3GPP TS23.304, Release 18. [Figure 6] FIG. 1 illustrates a method for relaying connections between nodes according to some embodiments, implemented at a source node. [Figure 7] FIG. 2 illustrates a method of relayed connection between nodes according to some embodiments, implemented in a relay node. [Figure 8] 6 and 7, which are exemplary message sequence diagrams corresponding to methods of relayed connections between nodes according to some embodiments of the present disclosure. [Figure 9] FIG. 1 illustrates a method for relaying connections between nodes according to some embodiments, implemented at a source node. [Figure 10] FIG. 2 illustrates a method of relayed connection between nodes according to some embodiments, implemented in a relay node. [Figure 11] 9 and 10 are exemplary message sequence diagrams corresponding to methods of relayed connections between nodes according to some embodiments of the present disclosure. [Figure 12] FIG. 1 illustrates a method for relaying connections between nodes according to some embodiments, implemented at a source node. [Figure 13] FIG. 2 illustrates a method of relayed connection between nodes according to some embodiments, implemented in a relay node. [Figure 14] 12 and 13 are exemplary message sequence diagrams corresponding to a method of relayed connection between nodes according to some embodiments of the present disclosure. [Figure 15]1 is an exemplary message sequence diagram corresponding to a method of relayed connection between nodes (multi-hop scenario) according to some embodiments of the present disclosure. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0117] The examples and embodiments set forth below represent information to enable those skilled in the art to practice the present disclosure. Upon reading the following description in light of the accompanying drawing figures, those skilled in the art will understand the concepts described therein and recognize applications of these concepts not specifically addressed herein. It should be understood that these concepts and applications are within the scope of this specification.

[0118] In the following description, numerous specific details are set forth. However, it should be understood that embodiments may be practiced without these specific details. In other instances, well-known circuits, structures, and techniques have not been shown in detail in order to avoid obscuring an understanding of this specification. Those skilled in the art will be able to use the included description to implement appropriate functionality without undue experimentation.

[0119] References herein to "one embodiment," "an embodiment," "an exemplary embodiment," etc., indicate that the described embodiment may include a particular feature, structure, or characteristic, but that not all embodiments necessarily 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 connection with one embodiment, it should be considered within the knowledge of one skilled in the art to implement such feature, structure, or characteristic in connection with other embodiments, whether or not explicitly described.

[0120] As used herein, "plurality" means two or more, and "a" means one or more. As used herein, a "set" of items may include one or more of such items. As used herein, whether in the disclosure or the claims, the terms "comprising," "including," "carrying," "having," "containing," "involving," and the like, are to be understood to be open-ended, i.e., meaning including but not limited to. Only the transitional phrases "consisting of" and "consisting essentially of," respectively, are closed or semi-closed transitional phrases with respect to the claims. The use of ordinal numbers such as "first," "second," "third," etc. to modify elements in the claims or this disclosure does not, in itself, imply a priority, ranking, or order of one element relative to another, or a temporal order in which method acts are performed, but is merely used as a label to distinguish one element having a certain name from another element having the same name (except in the case of ordinal numbers) so as to distinguish the elements. As used herein, "and / or" means that the listed items are in the alternative, but that the alternative includes any combination of the listed items.

[0121] Before describing examples according to the present disclosure in detail, certain general principles of wireless communication systems will be briefly explained with reference to Figures 1-3 to aid in understanding the technology behind the described examples.

[0122] 1 illustrates an example of a wireless network 100 that may be used for wireless communication. The wireless network 100 includes wireless devices, such as UEs 110 (e.g., 110A, 110B, 110C), and network nodes (e.g., eNBs, gNBs, etc.), such as radio access nodes 120 (e.g., 120A, 120B), which are connected to one or more network nodes 130 via an interconnection network 125. The network 100 may use any suitable deployment scenario. The UEs 110 within a coverage area 115 may each be able to communicate directly with the radio access nodes 120 over the air interface. In some embodiments, the UEs 110 may also be able to communicate with each other via device-to-device (D2D) communication. For example, UE 110A may communicate with UE 110C through UE 110B. In this scenario, UE 110B is acting as a relay device such that communication between UE 110A and UE 110C is indirect (relayed) communication.

[0123] The UE 110A may also communicate with the radio access node 120A over the air interface. That is, the UE 110A may transmit wireless signals to and / or receive wireless signals from the radio access node 120A. The wireless signals may contain voice traffic, data traffic, control signals, and / or any other suitable information.

[0124] As used herein, the term "user equipment (UE)" has the full scope of its ordinary meaning and may refer to any type of wireless device capable of communicating with a network node and / or with another UE in a cellular or mobile or wireless communication system. Examples of UEs include a target device, a D2D UE, a machine-type UE or a UE capable of machine-to-machine (M2M) communications, a personal digital assistant, a tablet, a mobile terminal, a smartphone, a laptop embedded equipment (LEE), a laptop mounted equipment (LME), a USB dongle, a ProSe UE, a vehicle-to-vehicle (V2V) UE, a V2X UE, an MTC UE, an eMTC UE, an FeMTC UE, a UE Cat 0, a UE Cat M1, a narrowband IoT (NB-IoT) UE, a UE Cat NB1, etc. Exemplary embodiments of a UE are described in more detail below with respect to FIG. 2.

[0125] In some embodiments, a radio signal coverage area 115 associated with a radio access node 120 may be referred to as a "cell." However, it is important to note that, particularly with regard to 5G concepts, a beam may be used instead of a cell, and therefore the concepts described herein are equally applicable to both cells and beams.

[0126] Interconnect network 125 may refer to any interconnect system capable of transmitting voice, video, signals, data, messages, etc., or any combination of the foregoing. Interconnect network 125 may include all or a portion of 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 telecommunications or computer network such as the Internet, a public land mobile network (PLMN), a wired or wireless network such as 4G and 5G networks, a corporate intranet, or any combination thereof.

[0127] In some embodiments, network node 130 may be a core network node that manages the establishment of communication sessions for UE 110 and various other functions. UE 110 may exchange certain signals with network node 130 using layers of the Non-Access Stratum (NAS). In Non-Access Stratum signaling, signals between UE 110 and network node 130 may pass transparently through the radio access network.

[0128] As used herein, the term "network node" has the full scope of its ordinary meaning and may correspond to any type of radio access node (or radio network node) or any network node capable of communicating with a UE and / or with another network node in a cellular or mobile or wireless communication system. Examples of network nodes include a NodeB, an MeNB, an SeNB, a network node that may belong to an MCG or an SCG, a base station (BS), an 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 station (BTS), an access point (AP), a transmission point, a transmitting node, a core network node (e.g., MSC, MME, etc.). Exemplary embodiments of network nodes are described in more detail below with respect to FIG. 3.

[0129] 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). Various 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., fiber optic cable), while in other architectures, the DU may be connected to the CU via a transport network. Also, how the various functions of the radio access node 120 are separated between the CU and the DU may vary depending on the architecture chosen.

[0130] An exemplary wireless communication system is an architecture standardized by the 3rd Generation Partnership Project (3GPP). The latest 3GPP-based development is often referred to as the Long Term Evolution (LTE) of the Universal Mobile Telecommunications System (UMTS) radio access technology (RAT). Various development stages of the 3GPP specifications are called releases. More recent developments of LTE are often referred to as LTE-Advanced (LTE-A). LTE (LTE-A) employs a wireless mobile architecture known as the Evolved Universal Terrestrial Radio Access Network (E-UTRAN) and a core network known as the Evolved Packet Core (EPC). The base stations in such systems are known as evolved or enhanced Node Bs (eNBs) and provide E-UTRAN functionality, such as user-plane Packet Data Convergence, Radio Link Control, Medium Access Control, and Physical layer protocols (PDCP, RLC, MAC, and PHY) and control-plane Radio Resource Control (RRC) protocol termination, for communication devices. Examples of other RATs include those provided by base stations in 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 a Mobility Management Entity (MME), a Serving Gateway (S-GW), and a Packet Gateway (P-GW).

[0131] An example of a suitable communication system is the 5G or NR concept. The network architecture in NR may be similar to that of LTE-A. Base stations in NR systems may be known as next-generation Node Bs (gNBs). Changes to the network architecture may depend on the need to support various radio technologies and more granular 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 may use multiple-input multiple-output (MIMO) antennas and more base stations or nodes than LTE (the so-called small cell concept), including macro sites that operate in conjunction with small stations and possibly also employ various radio technologies for better coverage and enhanced data rates.

[0132] Future networks may utilize network function virtualization (NFV), a network architecture concept that proposes virtualizing network node functions into "building blocks" or entities that can be operatively connected or linked together to provide services. A virtualized network function (VNF) may include one or more virtual machines that run computer program code using standard or generic types of servers instead of customized hardware. Cloud computing or data storage may also be utilized. In wireless communications, this may mean that node operations are performed, at least in part, in a server, host, or node operatively coupled to a remote radio head. It is also possible that node operations may be distributed among multiple servers, nodes, or hosts. It should also be understood that the distribution of labor between core network operations and base station operations may differ from or even exist in LTE.

[0133] An exemplary 5G Core Network (CN) includes functional entities. The CN is connected to the UE via a Radio Access Network (RAN). A User Plane Function (UPF), whose role may be referred to as a PDU Session Anchor (PSA), is responsible for forwarding frames back and forth between a Data Network (DN) and a tunnel established over 5G for the UE that exchanges traffic with the Data Network (DN). The UPF is controlled by a Session Management Function (SMF), which receives policies from a Policy Control Function (PCF). The CN may also include an Access & Mobility Function (AMF).

[0134] 2 is a schematic diagram of an exemplary wireless device, UE 110, in accordance with a particular embodiment. UE 110 includes a transceiver 210, a processor 220, a memory 230, and a network interface 240. In some embodiments, transceiver 210 facilitates transmission of wireless signals to and reception of wireless signals from radio access node 120 (e.g., via a transmitter (Tx), a receiver (Rx), and an antenna). Processor 220 executes instructions for providing 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 a processing circuit.

[0135] The processor 220 may include any suitable combination of hardware for executing instructions and manipulating data to perform some or all of the functions of the described wireless device, e.g., the functions of the UE 110 described herein. 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.

[0136] Memory 230 is generally operable to store instructions for computer programs, software, applications, etc., including one or more of logic, rules, algorithms, codes, tables, etc., and / or other instructions executable by processor 220. Examples of memory 230 include computer memory (e.g., Random Access Memory (RAM) or Read Only Memory (ROM)), mass storage media (e.g., hard disks), 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 devices that store information, data, and / or instructions that may be used by processor 220 of UE 110. For example, memory 230 includes computer program code that causes processor 220 to perform processing according to the methods described below with respect to FIGS. 4-15.

[0137] Network interface 240 may refer to any suitable device communicatively coupled to processor 220 and operable to receive input to UE 110, send output from UE 110, perform suitable processing on the input or output or both, communicate to other devices, or any combination thereof. Network interface 240 may include appropriate hardware (e.g., ports, modems, network interface cards, etc.) and software, including protocol conversion and data processing capabilities, for communicating over a network.

[0138] Other embodiments of the UE 110 may include additional components, in addition to the components shown in FIG. 2, that may be responsible for providing certain aspects of the wireless device's functionality, including any of the functionality described herein and / or any additional functionality (including any functionality necessary 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 inputting 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 hardcopy form. For example, the output devices may include a speaker, a display, etc.

[0139] In some embodiments, wireless device UE 110 may comprise a series of modules configured to implement the functionality of the wireless device described herein.

[0140] It will be appreciated that the various modules may be implemented as a combination of hardware and software, such as the processor, memory, and transceiver of the UE 110 shown in Figure 2. Some embodiments may also include additional modules to support additional and / or optional functionality.

[0141] 3 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 a transceiver 310, a processor 320, a memory 330, and a network interface 340. In some embodiments, the transceiver 310 facilitates transmission of wireless signals to and reception of wireless signals from a wireless device, such as a UE 110 (e.g., via a transmitter (Tx), a receiver (Rx), and an antenna). 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 can communicate signals to back-end network components, such as gateways, switches, routers, the Internet, a Public Switched Telephone Network (PSTN), a core network node, or a radio network controller.

[0142] The processor 320 may include any suitable combination of hardware for executing instructions and manipulating data to perform some or all of the described 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.

[0143] Memory 330 is generally operable to store instructions for computer programs, software, applications, etc., including one or more of logic, rules, algorithms, codes, tables, etc., and / or other instructions executable by processor 320. Examples of memory 330 include computer memory (e.g., Random Access Memory (RAM) or Read Only Memory (ROM)), mass storage media (e.g., hard disks), 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, memory 330 includes computer program code that causes processor 320 to perform processing according to the methods described below with respect to FIG. 11.

[0144] In some embodiments, network interface 340 may refer to any suitable device communicatively coupled to processor 320 and operable to receive input to radio access node 120 or network node 130, send output from radio access node 120 or network node 130, perform suitable processing on the input or output or both, communicate to other devices, or any combination of the foregoing. Network interface 340 may include appropriate hardware (e.g., ports, modems, network interface cards, etc.) and software, including protocol conversion and data processing capabilities, for communicating over a network.

[0145] Other embodiments of the radio access node 120 or network node 130 may include additional components in addition to the components shown in Figure 3 that may be responsible for providing certain aspects of the node's functionality, including any of the functionality described herein and / or any additional functionality (including any functionality necessary to support the solutions described herein). Various different types of radio access nodes or network nodes may have the same physical hardware but include components that are configured (e.g., by programming) to support different radio access technologies, or may represent different physical components in part or in whole.

[0146] Processors, interfaces, and memories similar to those described with respect to Figure 3 may be included in other nodes (such as the UE 110, the radio access node 120, etc.), which may or may not optionally include a radio interface (such as the transceiver described in Figure 3).

[0147] In some embodiments, the radio access node 120 or the network node 130 may comprise a series of modules configured to implement the functionality of the radio access node 120 or the network node 130 described herein.

[0148] It will be understood that the various modules may be implemented as a combination of hardware and software, such as the processor, memory, and transceiver of the radio access node 120 or network node 130 shown in Figure 3. Some embodiments may also include additional modules to support additional and / or optional functionality.

[0149] Before describing methods of relayed connections between nodes according to some embodiments of the present disclosure with reference to FIGS. 6-15, certain background information and aspects related to the present disclosure are provided.

[0150] 3GPP TS23.304, Release 18 (version V18.0.0, 2022-12), which is incorporated herein by reference, specifies Proximity-based Service (ProSe) features in 5G LTE. These 5G ProSe features include, among other things, 5G ProSe UE-to-UE Relay, which enables indirect communication between two 5G ProSe End UEs (also referred to herein as a relay connection between nodes).

[0151] An exemplary reference architecture described in 3GPP TS23.304, Release 18 is shown in Figure 4. More specifically, the exemplary reference architecture illustrates a reference architecture for 5G ProSe UE-to-UE Relay at Layer-2 and Layer-3.

[0152] Figure 4 shows two 5G ProSe End UEs communicating with each other via a 5G ProSe UE-to-UE Relay. Each 5G ProSe End UE and 5G ProSe UE-to-UE Relay may have a subscription from the same Public Land Mobile Network (PLMN) or from a different PLMN. 3GPP TS 23.304, Release 18, specifies the PC5 reference point between UEs that support 5G ProSe requirements and related procedures (referred to as ProSe-capable UEs), such as each 5G ProSe End UE and 5G ProSe UE-to-UE Relay. The PC5 reference point is used for the control and user plane of a procedure used by a 5G ProSe-enabled UE to discover other 5G ProSe-enabled UEs in its vicinity based on direct wireless transmission between the two UEs using NR technology (called 5G ProSe Direct Discovery), communication between two or more nearby 5G ProSe-enabled UEs via a path that does not traverse any network nodes and is performed by user plane transmission using NR technology (called 5G ProSe Direct Communication), and 5G ProSe-enabled UEs that provide functionality to support connectivity between 5G ProSe End UEs (called 5G ProSe UE-to-UE Relay) and / or to support network connectivity for 5G ProSe-enabled UEs that communicate with a Data Network (DN) via a 5G ProSe UE-to-Network Relay (called 5G ProSe UE-to-Network Relay).

[0153] 3GPP TS 23.304, Release 18 further specifies that any 5G ProSe-capable UE may support, among other things, procedures for 5G ProSe Direct Communication over the PC5 reference point, including 5G ProSe Direct Communication in Broadcast, Groupcast, 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 End UE, and procedures for acting as a 5G ProSe Layer-3 End UE.

[0154] An example of a procedure for 5G ProSe Communication via 5G ProSe UE-to-UE Relay is described in 3GPP TS23.304, Release 18, and is shown in FIG. 5.

[0155] As shown in Figure 5, a source 5G ProSe Layer-3 End UE (i.e., a source node) communicates with a target 5G ProSe Layer-3 End UE (i.e., a target node) via a 5G ProSe Layer-3 UE-to-UE Relay (i.e., a relay node). The source 5G ProSe Layer-3 End UE, the target 5G ProSe Layer-3 End UE, and the 5G ProSe Layer-3 UE-to-UE Relay may be connected to the same PLMN or different PLMNs.

[0156] In step 1, service authorization and provisioning is performed for the source 5G ProSe Layer-3 End UE, the target 5G ProSe Layer-3 End UE, and the 5G ProSe Layer-3 UE-to-UE Relay. The procedure for service authorization and provisioning for the UE is described in 3GPP TS23.304, Release 18.

[0157] In step 2, the source 5G ProSe Layer-3 End UE performs 5G ProSe Layer-3 UE-to-UE Relay discovery. The discovery procedure is described in 3GPP TS23.304, Release 18.

[0158] In step 3, the source 5G ProSe Layer-3 End 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-allocated by the source 5G ProSe Layer-3 End UE, and the Destination Layer-2 ID is set to the Source Layer-2 ID of the 5G ProSe Layer-3 UE-to-UE Relay discovery message.

[0159] In step 4, if the User Info ID of the target 5G ProSe Layer-3 End UE and the User Info 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 End UE. If security protection is enabled, the source 5G ProSe Layer-3 End UE sends IP Address Configuration and QoS Info to the 5G ProSe Layer-3 UE-to-UE Relay. The Source Layer-2 ID used for the security establishment procedure is self-allocated 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. Upon receiving the security establishment procedure message, the source 5G ProSe Layer-3 End UE obtains the Layer-2 ID of the 5G ProSe Layer-3 UE-to-UE Relay for future communication for signaling and data traffic on this unicast link.

[0160] 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 End UE. The source Layer-2 ID of the Direct Communication Request message is self-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 End UE associated with the User Info ID of the target 5G ProSe Layer-3 End UE.

[0161] In step 6, if the User Info ID of the target 5G ProSe Layer-3 End UE is included in the Direct Communication Request message, the target 5G ProSe Layer-3 End UE responds by establishing security with the 5G ProSe Layer-3 UE-to-UE Relay. If security protection is enabled, the 5G ProSe Layer-3 UE-to-UE Relay sends IP Address Configuration and QoS Info to the target 5G ProSe Layer-3 End UE. The Source Layer-2 ID used in the security establishment procedure is self-allocated by the target 5G ProSe Layer-3 End UE, and the Destination Layer-2 ID is set to the Source Layer-2 ID of the received Direct Communication Request message. Upon 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 End UE for future communication for signaling and data traffic on this unicast link.

[0162] In step 7, the target 5G ProSe Layer-3 End UE sends a Direct Communication Accept message to the 5G ProSe Layer-3 UE-to-UE Relay with which security has been successfully established.

[0163] Optionally, for Internet Protocol (IP) traffic, in step 8, an IP address is assigned to the target 5G ProSe Layer-3 End UE.

[0164] In step 9, after receiving the Direct Communication Accept message from the target 5G ProSe Layer-3 End UE, the 5G ProSe Layer-3 UE-to-UE Relay sends a Direct Communication Accept message to the source 5G ProSe Layer-3 End UE with which security has been successfully established.

[0165] Optionally, for IP traffic, in step 10, the 5G ProSe Layer-3 UE-to-UE Relay and the source 5G ProSe Layer-3 End UE exchange Domain Name Service (DNS) messages for the IP address for the source 5G ProSe Layer-3 End UE (steps 11a and 11b).

[0166] In step 12, the source 5G ProSe Layer-3 End UE communicates with the target 5G ProSe Layer-3 End UE via a 5G ProSe Layer-3 UE-to-UE Relay, i.e., the source 5G ProSe Layer-3 End UE performs relay communication with the target 5G ProSe Layer-3 End UE via the 5G ProSe Layer-3 UE-to-UE Relay.

[0167] Signaling messages for Direct Communication over the PC5 reference point between a source 5G ProSe Layer-3 End UE and a target 5G ProSe Layer-3 End UE are described in the 5G ProSe Direct Link Establishment procedure of 3GPP TS24.554, Release 17 (Version V17.3.0, 2022-12), which is incorporated herein by reference. According to the 5G ProSe Direct Link Establishment procedure, an initiating UE (e.g., a source 5G ProSe Layer-3 End 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 request by returning a PROSE DIRECT LINK ESTABLISHMENT REJECT message. Steps 3 and 9 in Figure 5 represent the 5G ProSe direct link establishment procedure between the source 5G ProSe Layer-3 End UE as the initiating UE and the 5G ProSe Layer-3 UE-to-UE Relay as the target UE. Steps 5 and 7 in Figure 5 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 End UE as the target UE.

[0168] According to 3GPP TS24.554, 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 about the cause of rejecting the 5G ProSe direct link establishment request, the PROSE DIRECT LINK ESTABLISHMENT REJECT message includes the information element "PC5 Signaling Protocol Cause", which carries the protocol cause of the rejection as described in 3GPP TS24.554, Release 17.

[0169] The initiating UE utilizes the "PC5 signaling protocol cause" information to determine whether the failure (i.e., rejection) is permanent or temporary and takes appropriate next action. Based on the protocol cause of the rejection, the initiating UE decides to retry the connection establishment with the same target UE, or whether the initiating UE needs to perform a relay reselection procedure to discover another relay UE.

[0170] In some examples, direct communication (i.e., connection) between the source 5G ProSe Layer-3 End UE and the 5G ProSe Layer-3 UE-to-UE Relay and / or between the 5G ProSe Layer-3 UE-to-UE Relay and the target 5G ProSe Layer-3 End UE may already be established and available. In this case, the 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, and if the modification is rejected, a PROSE DIRECT LINK MODIFICATION REJECT message may be used. To inform the initiating UE about the cause of rejecting the 5G ProSe Direct Link Modification Request, the PROSE DIRECT LINK MODIFICATION REJECT message includes the information element "PC5 Signaling Protocol Cause" which holds the protocol cause of the rejection, similar to the PROSE DIRECT LINK ESTABLISHMENT REJECT message.

[0171] However, a problem arises when a failure / rejection occurs between the 5G ProSe Layer-3 UE-to-UE Relay and the target 5G ProSe Layer-3 End UE because the source 5G ProSe Layer-3 End UE is not notified by the target 5G ProSe Layer-3 End UE about the cause of this failure / rejection. Therefore, the source 5G ProSe Layer-3 End 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 End UE and therefore cannot take appropriate next action.

[0172] The present disclosure provides a mechanism for relay connection between nodes (i.e., a source 5G ProSe End UE and a target 5G ProSe End UE) to contribute to solving the above-mentioned problem. By addressing this problem, the present disclosure enables a source 5G ProSe End UE to utilize information about a failure / rejection that occurred between a 5G ProSe UE-to-UE Relay and a target 5G ProSe End UE so that the source 5G ProSe End UE can take appropriate next action in the event of a failure / rejection.

[0173] An exemplary method of relaying connections between nodes according to some embodiments of the present disclosure will now be described.

[0174] FIG. 6 illustrates a method 600 for relaying connections between nodes according to some embodiments.

[0175] Method 600 is performed by a source node, such as a user device (e.g., user equipment (UE)), or by an apparatus used at a source node. The source node includes a 5G ProSe-enabled UE and represents the source 5G ProSe End UE described above. In some examples, the source node may be represented by any of the UEs 110A of wireless network 100 described above with reference to FIG. 1 or wireless devices such as wireless device 110 described above with reference to FIG. 2.

[0176] A relay node may be a user device (e.g., user equipment (UE)) or a device used in a relay node. A relay node includes a 5G ProSe-enabled UE, representing the 5G ProSe UE-to-UE Relay described above. In some examples, a relay node may be represented by any of the UEs 110B of wireless network 100 described above with respect to FIG. 1 or wireless devices such as wireless device 110 described above with respect to FIG. 2.

[0177] The target node may be a user device (e.g., user equipment (UE)) or a device used at the target node. The target node includes a 5G ProSe-enabled UE and represents the target 5G ProSe End UE described above. In some examples, the target node may be represented by any of the UEs 110C of the wireless network 100 described above with respect to FIG. 1 or wireless devices such as the wireless device 110 described above with respect to FIG. 2.

[0178] The source node, relay node, and target node are connected to and served by network 100. More specifically, the source node, relay node, and target node are located within an area (i.e., cell 115) served by a base station (e.g., gNB 120A, 120B) and use services provided or supported by network 100. For example, network 100 may support Proximity-based Services (ProSe), which enables 5G ProSe Communication via 5G ProSe UE-to-UE Relay (i.e., indirect / relay communication via a relay device). As mentioned above, the source node, relay node, and target node may be connected to the same PLMN or different PLMNs.

[0179] Method 600 begins at block 610. In block 610, a source node sends a communication request message to a relay node to establish a connection to a target node through the relay node. With the communication request message, the source node requests to establish an indirect connection from the source node to the target node through the relay node by establishing 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.

[0180] In some examples, the communication request message to establish a connection includes a PROSE DIRECT LINK ESTABLISHMENT REQUEST message.

[0181] Additionally, the source node may start a timer (e.g., T5080) in response to sending the communication request message to the relay node. The timer indicates a period during which the source node must 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 retransmit the communication request message to the relay node if a connection to the target node is still to be established.

[0182] In block 620, the source node receives a communication refusal message from the relay node indicating a refusal to establish a connection by the target node. With the communication refusal message, the relay node indicates to the source node that the target node has refused to establish a second direct connection, thereby notifying the source node. In other words, the second hop was not established due to a failure or refusal to establish the second direct connection. Due to the failure or refusal, the connection to the target node requested by the source node was not established.

[0183] In some examples, the communication refusal message indicating the refusal to establish a connection includes a PROSE DIRECT LINK ESTABLISHMENT REJECT message.

[0184] In some examples, the communication rejection message includes a cause value (i.e., one or more cause values) to indicate the rejection by the target node. For example, the PROSE DIRECT LINK ESTABLISHMENT REJECT message may include a PC5 failure cause that indicates to the source node that the connection establishment was rejected and therefore failed due to a connection rejection from the target node, rather than a rejection from a relay node. As described in more detail below, the new PC5 failure cause may be used to indicate to the source 5G ProSe End UE that the failure was due to a connection rejection from the target 5G ProSe End UE, rather than a rejection from the 5G ProSe UE-to-UE Relay itself.

[0185] In some examples, an existing information element (IE) for signaling a cause value of a relay node in a communication rejection message may include a cause value indicating a rejection by the target node. For example, the PROSE DIRECT LINK ESTABLISHMENT REJECT message includes an IE (e.g., a PC5 signaling protocol cause IE) for indicating a cause value from a relay node to a source node. Because the above IE may be used to indicate a rejection by a target node, it may be extended to indicate the cause value of the target node as well. As described below, a new PC5 failure cause may be provided in the existing PC5 signaling protocol cause IE used to signal a rejection cause for 5G ProSe UE-to-UE Relay.

[0186] Additionally or alternatively, in some examples, the communication rejection message may include an additional IE for signaling a cause value of the target node. The additional IE indicates the rejection by the target node and is used to provide additional details (i.e., a cause value) that indicate to the source node why establishing the connection was rejected by the target node. The additional IE may be optional and is included in the communication rejection message if the existing IE indicates the rejection by the target node. That is, in some examples, the existing IE for signaling a cause value of 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, and the additional IE provides a cause value that indicates the reason for the connection rejection by the target node. As described below, an additional PC5 end UE failure cause IE may be included in the PROSE DIRECT LINK ESTABLISHMENT REJECT message. The PC5 end UE failure cause IE holds the rejection cause provided by the target node (i.e., the target 5G ProSe End UE itself) and is included when a new PC5 failure cause is provided by the PC5 signaling protocol cause IE. When generating the PROSE DIRECT LINK ESTABLISHMENT REJECT message, the relay node (i.e., 5G ProSe UE-to-UE Relay) includes an additional PC5 End 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 End UE). Based on the rejection cause values ​​in the PC5 signaling protocol cause IE and the PC5 End UE Failure Cause IE, the source node (i.e., source 5G ProSe End UE) is notified about the reason why the target node (i.e., target 5G ProSe End UE) rejected the establishment of the connection (i.e., the PC5 connection between the relay node and the target node).

[0187] In some examples, an existing information element (IE) for signaling a cause value of a relay node in a communication rejection message may also be extended to signal a rejection cause value of a target node, i.e., the existing PC5 signaling protocol cause IE in a PROSE DIRECT LINK ESTABLISHMENT REJECT message may be extended by adding multiple additional cause values ​​that represent failure situations by the target node (i.e., target 5G ProSe End UE).

[0188] Additionally, in some examples, the source node may stop a timer (e.g., T5080) in response to receiving a communication rejection message from the relay node. Before stopping the timer, the source node may check whether a communication rejection message was received before the timer expired.

[0189] In some examples, if the source node receives a communication refusal message indicating a refusal by the target node to establish a connection (block 620), the source node may implement a procedure to handle or address the refusal by the target node (block 630). Example procedures include a retry procedure to retry establishing the connection, a relay reselection procedure to select another relay node through which to establish the connection, and a discovery procedure to discover another target node to establish a connection with.

[0190] In some examples, if the source node receives a communication rejection message indicating a rejection of the establishment of a connection by the target node (block 620), the source node may retry establishing a connection to the target node by sending another communication request message to establish a connection to the target node via a relay node (block 630A). The procedure of sending another communication request message corresponds to the sending of the communication request message of block 610. Preferably, the source node may initiate a retry 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 a connection to the target node should still 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.

[0191] In some examples, if the source node receives a communication rejection message indicating a refusal by the target node to establish a connection (block 620), the source node may perform a relay reselection procedure to select another relay node and send a new communication request message to establish a connection to the target node through the other relay node (block 630B). The procedure of sending the new communication request message corresponds to sending the communication request message of block 610, but the communication request message is sent not to the relay node but to the other relay node selected by the relay reselection procedure. To determine whether to perform the relay reselection procedure, the source node may consider the reason (e.g., one or more cause values) for the refusal by the target node to establish the connection as provided in the communication rejection message.

[0192] In some examples, if the source node receives a communication rejection message indicating a rejection of the establishment of a connection by the target node (block 620), 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 cause values) for the rejection of the establishment of the 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 procedure to discover another target node with which to establish a connection via a relay node or another relay node. In response to discovering the other target node, the source node transmits a new communication request message to the relay node or other relay device to establish a connection to the other target node via the relay node or other relay device. The procedure for transmitting the new communication request message corresponds to transmitting the communication request message of block 610, but the communication request message is transmitted directed to the other target node.

[0193] In method 600, the source node is notified that the denial is due to a denial caused by the target node to establish a connection (ie, a second hop) between the relay node and the target node.

[0194] FIG. 7 illustrates a method 700 of relayed connections between nodes according to some embodiments.

[0195] Method 700 is performed by a relay node, such as a user device (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 the 5G ProSe UE-to-UE Relay described above. In some examples, the relay node may be represented by any of the UEs 110B of the wireless network 100 described above with reference to FIG. 1 or wireless devices such as the wireless device 110 described above with reference to FIG. 2.

[0196] The source node may be a user device (e.g., user equipment (UE)) or a device used at the source node. The source node includes a 5G ProSe-enabled UE and represents the source 5G ProSe End UE described above. In some examples, the source node may be represented by any of the UEs 110A of the wireless network 100 described above with respect to FIG. 1 or wireless devices such as the wireless device 110 described above with respect to FIG. 2.

[0197] The target node may also be a user device (e.g., user equipment (UE)) or a device used at the target node. The target node includes a 5G ProSe-enabled UE and represents the target 5G ProSe End UE described above. In some examples, the target node may be represented by any of the UEs 110C of the wireless network 100 described above with reference to FIG. 1 or wireless devices such as the wireless device 110 described above with reference to FIG. 2.

[0198] 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.

[0199] Method 700 begins at block 710. At block 710, a relay node receives a communication request message from a source node to establish a connection to a target node via the relay node. With the communication request message, the source node requests to establish an indirect connection from the source node to the target node via the relay node by establishing a first direct connection (i.e., first hop) between the source node and the relay node and a second direct connection (i.e., second hop) between the relay node and the target node.

[0200] In some examples, the communication request message to establish a connection includes a PROSE DIRECT LINK ESTABLISHMENT REQUEST message.

[0201] At block 720, the relay node attempts to establish a connection (i.e., a second hop) to the target node. More specifically, the relay node initiates a procedure 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) to establish a connection to the target node, and establish a connection between the relay node and the target node by receiving a communication accept message (e.g., a PROSE DIRECT LINK ESTABLISHMENT ACCEPT message) from the target node, or receive a communication rejection message (e.g., a PROSE DIRECT LINK ESTABLISHMENT REJECT message) indicating a rejection of the establishment of the connection by the target node.

[0202] If the relay node receives a communication refusal message (i.e., a refusal by the target node to establish a connection), the relay node sends a communication refusal message to the source node that requested the establishment of communication to the target node via the relay node, indicating the refusal by the target node to establish a connection (block 730). With the communication refusal message, the relay node indicates to the source node that the target node has refused to establish a second direct connection, thereby notifying the source node. In other words, the second hop was not established due to the failure or refusal to establish the second direct connection. As a result, the connection to the target node requested by the source node was not established due to the failure or refusal.

[0203] Details regarding the indication of refusal to establish a connection by the target node in the communication refusal message sent by the relay node to the source node are described above in connection with method 600. Therefore, a repetition of those details will be omitted here.

[0204] Figure 8 shows an example message sequence diagram corresponding to the method of relay connection between nodes according to some embodiments of the present disclosure, as described above with respect to Figures 6 and 7. More specifically, the example message sequence diagram of Figure 8 relates to 5G ProSe Communication via 5G ProSe UE-to-UE Relay using a Direct Link Establishment procedure in case of failure / rejection by the target node (e.g., target 5G ProSe End UE).

[0205] Steps 1, 2, and 4 shown in Figure 8 correspond to steps 1, 2, and 4 in Figure 5. Therefore, to avoid repetition, detailed descriptions will be omitted here.

[0206] In step 3, the source 5G ProSe End 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 to establish a connection to the target node via the relay node (i.e., block 610 in FIG. 6 and block 710 in FIG. 7).

[0207] For example, the Direct Communication Request message may include a PROSE DIRECT LINK ESTABLISHMENT REQUEST message.

[0208] 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 End UE (step 5). The Direct Communication Request message sent in step 5 causes the relay node to attempt to establish a connection to the target node (i.e., block 720 of FIG. 7).

[0209] For example, the Direct Communication Request message may include a PROSE DIRECT LINK ESTABLISHMENT REQUEST message.

[0210] If the link establishment procedure fails due to a failure or rejection by the 5G ProSe End UE, the target 5G ProSe End 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 End UE.

[0211] For example, a Direct Communication Reject message (e.g., a PROSE DIRECT LINK ESTABLISHMENT REJECT message) may include an information element such as a PC5 signaling protocol cause IE used to signal a cause value. The PC5 signaling protocol cause IE may include a cause value (i.e., one or more cause values) indicating the cause of the rejection of the target 5G ProSe End UE (e.g., value X shown in FIG. 8).

[0212] In response to receiving the Direct Communication Reject message from the target 5G ProSe End UE, the 5G ProSe UE-to-UE Relay sends a Direct Communication Reject message to the source 5G ProSe End UE (step 7). Step 7 corresponds to sending a communication rejection message indicating a rejection of the establishment of the connection by the target node (i.e., block 620 of FIG. 6 and block 730 of FIG. 7). The Direct Communication Reject message includes an indication of the rejection by the target 5G ProSe End UE.

[0213] For example, the Direct Communication Reject message may include a PROSE DIRECT LINK ESTABLISHMENT REJECT message indicating a failure from the target 5G ProSe End UE. More specifically, the Direct Communication Reject message (e.g., a PROSE DIRECT LINK ESTABLISHMENT REJECT message) may include an information element such as a (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 End UE to the source 5G ProSe End 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 End UE. Furthermore, the Direct Communication Reject message (e.g., a PROSE DIRECT LINK ESTABLISHMENT REJECT message) may further include a new PC5 signaling protocol cause IE (also referred to as a PC5 end UE failure cause IE) for signaling a cause value of the target 5G ProSe End UE. The new PC5 signaling protocol cause IE may be optional and may be included when the (existing) PC5 signaling protocol cause IE indicates a rejection by the target 5G ProSe End UE. The new PC5 signaling protocol cause IE may include one or more cause values ​​(e.g., the value X shown in FIG. 8) for indicating a rejection cause of the target 5G ProSe End UE, similar to the cause values ​​indicating the rejection cause of 5G ProSe UE-to-UE Relay.

[0214] In response to receiving the Direct Communication Reject message from the 5G ProSe UE-to-UE Relay, the source 5G ProSe End UE may determine a next step (step 8) based on the indication of rejection by the target 5G ProSe End 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 step in step 8 may include procedures corresponding to block 630 of FIG. 6.

[0215] FIG. 9 illustrates a method 900 of relayed connections between nodes according to some embodiments.

[0216] Method 900 is performed by a source node such as a user device (e.g., user equipment (UE)) or by an apparatus used in the source node (e.g., source 5G ProSe End UE) as described above. The relay node and target node may each be a user device (e.g., user equipment (UE)) or an apparatus used in the user device (e.g., 5G ProSe UE-to-UE Relay and target 5G ProSe End UE, respectively), as described above.

[0217] In method 900, the source node has an established connection to the relay node (i.e., 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 described above.

[0218] In block 910, the source node sends a communication request message to the relay node to modify 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 establish an (indirect) connection from the source node to the target node via the relay node by modifying an existing direct connection (i.e., first hop) between the source node and the relay node and establishing a direct connection (i.e., second hop) between the relay node and the target node.

[0219] In some examples, the communication request message to modify an existing connection includes a PROSE DIRECT LINK MODIFICATION REQUEST message.

[0220] In block 920, the source node receives a communication refusal message from the relay node indicating a refusal to modify the existing connection due to the target node's refusal to establish the connection. With the communication refusal message, the relay node indicates to, and thus notifies, the source node that the target node has refused to establish a direct connection between the relay node and the target node. In other words, the second hop was not established due to the failure or refusal to establish the direct connection.

[0221] In some examples, the communication refusal message indicating the refusal to establish the connection includes a PROSE DIRECT LINK MODIFICATION REJECT message.

[0222] The instruction to refuse to modify an existing connection due to a refusal by the target node to establish a connection corresponds to the instruction to refuse to establish a connection by the target node described above in relation to Figure 6. Therefore, a repetition of the details will be omitted here.

[0223] In some examples, if the source node receives a communication refusal message indicating a refusal to modify an existing connection due to a refusal by the target node to establish the connection (block 920), the source node may implement procedures to handle or address the refusal by the target node (block 930), examples of such procedures are described above in connection with block 630 of FIG.

[0224] According to the method 900 described above, the source node is notified that the denial is due to a denial caused by the target node to the establishment of a connection (i.e., a second hop) between the relay node and the target node.

[0225] In some examples, a source device may attempt to connect to or be connected to multiple target nodes. In such examples, a communication rejection message indicating a refusal to modify a connection may include identification information indicating a target node among the multiple target nodes that caused the refusal. The source node may derive the target node that caused the refusal based on the identification information. That is, the source node may derive the identity of the target node. In some examples, the communication rejection message may include target end UE information to indicate the user information ID of the target node (i.e., 5G ProSe End UE) when the refusal occurred in the first hop due to a refusal to establish a connection in the second hop. This allows the source node to know which target node is refusing to establish a connection when the source node is attempting to establish a connection with multiple target nodes.

[0226] FIG. 10 illustrates a method 1000 of relayed connections between nodes according to some embodiments.

[0227] Method 1000 is performed by a relay node such as a user device (e.g., user equipment (UE)) or by an apparatus used in the relay node (e.g., 5G ProSe UE-to-UE Relay) described above. The source node and the target node may each be a user device (e.g., user equipment (UE)) or an apparatus used in the user device (e.g., source 5G ProSe End UE and target 5G ProSe End UE, respectively).

[0228] In method 1000, the source node has an established connection to the relay node (i.e., 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 described above.

[0229] In block 1010, the relay node receives a communication request message from the source node to establish a connection to the target node by modifying an existing connection between the source node and the relay node. The communication request message causes the source node to request the establishment of an (indirect) connection from the source node to the target node via the relay node by modifying an existing direct connection (i.e., first hop) between the source node and the relay node and establishing a direct connection (i.e., second hop) between the relay node and the target node.

[0230] In some examples, the communication request message to modify an existing connection includes a PROSE DIRECT LINK MODIFICATION REQUEST message.

[0231] In block 1020, the relay node establishes or attempts to establish a connection (i.e., a second hop) to the target node. More specifically, the relay node performs a procedure for establishing a connection to the target node. For example, the relay node sends a communication request message (e.g., a PROSE DIRECT LINK ESTABLISHMENT REQUEST message) to establish a (direct) connection to the target node and receives a communication accept message (e.g., a PROSE DIRECT LINK ESTABLISHMENT ACCEPT message) from the target node, thereby establishing a connection between the relay node and the target node, or receives a communication rejection message (e.g., a PROSE DIRECT LINK ESTABLISHMENT REJECT message) indicating the target node's rejection of the establishment of the connection.

[0232] If the relay node receives a communication refusal message (i.e., a refusal by the target node to establish a connection), the relay node sends a communication refusal message to the source node that requested establishing communication to the target node through the relay node indicating a refusal to modify the existing connection due to the target node's refusal to establish the connection (block 1030). With the communication refusal message, the relay node indicates to the source node that the target node has refused to establish a second direct connection, thereby notifying the source node. In other words, the second hop was not established due to the failure or refusal to establish the second direct connection.

[0233] In some examples, the communication refusal message indicating the refusal to establish the connection includes a PROSE DIRECT LINK MODIFICATION REJECT message.

[0234] Details regarding the indication of refusal in the communication refusal message sent by the relay node to the source node are described above in connection with method 600 of Figure 6. Therefore, a repetition of those details will be omitted here.

[0235] Figure 11 illustrates an example message sequence diagram corresponding to a method for relayed connection between nodes according to some embodiments of the present disclosure, as described above with respect to Figures 9 and 10. More specifically, the example message sequence diagram of Figure 11 relates to 5G ProSe Communication over 5G ProSe UE-to-UE Relay using a Direct Link Modification procedure in the first hop in case of failure / rejection by the target node (e.g., target 5G ProSe End UE).

[0236] The source 5G ProSe End UE and the 5G ProSe UE-to-UE Relay have an (existing) connection brought about by, for example, performing the link establishment procedure described above.

[0237] Steps 1 and 2 shown in Figure 11 correspond to steps 1 and 2 in Figure 5. Therefore, detailed descriptions are omitted here to avoid repetition.

[0238] In step 3, the source 5G ProSe End UE initiates a link modification procedure with the 5G ProSe UE-to-UE Relay by sending a Direct Modification Request message. That is, the source 5G ProSe End UE sends a Direct Modification Request message to modify the existing connection. Step 3 corresponds to sending a communication request message to modify the existing connection to the relay node and establish a connection to the target node (i.e., block 910 in FIG. 9 and block 1010 in FIG. 10).

[0239] For example, the Direct Modification Request message may include a PROSE DIRECT LINK MODIFICATION REQUEST message.

[0240] In response to receiving the Direct Modification Request message, the 5G ProSe UE-to-UE Relay initiates a link establishment procedure with the target 5G ProSe End UE by sending a Direct Communication Request message (step 4). The Direct Communication Request message causes the relay node to attempt to establish a connection to the target node (i.e., block 1020 of FIG. 10). More specifically, the 5G ProSe UE-to-UE Relay initiates a link establishment procedure to establish a connection with the target 5G ProSe End UE.

[0241] For example, the Direct Communication Request message may include a PROSE DIRECT LINK ESTABLISHMENT REQUEST message.

[0242] The link establishment procedure may fail due to a failure or rejection by the target 5G ProSe End UE, and the target 5G ProSe End 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 End UE. For example, the Direct Communication Reject message (e.g., a PROSE DIRECT LINK ESTABLISHMENT REJECT message) may include an information element such as a PC5 signaling protocol cause IE used to signal a cause value. The PC5 signaling protocol cause IE may include a cause value (i.e., one or more cause values) that indicates the rejection cause of the target 5G ProSe End UE (e.g., the value X shown in FIG. 11).

[0243] In response to receiving the Direct Communication Reject message from the target 5G ProSe End UE, the 5G ProSe UE-to-UE Relay sends a Direct Modification Reject message to the source 5G ProSe End UE (step 6). Step 6 corresponds to sending a communication rejection message indicating a rejection to the modification of the existing connection due to the target node's rejection to the establishment of the connection (i.e., block 920 of FIG. 9 and block 1030 of FIG. 10). The Direct Modification Reject message includes an indication of the rejection by the target 5G ProSe End UE.

[0244] For example, the Direct Modification Reject message may include a PROSE DIRECT LINK MODIFICATION REJECT message indicating a failure from the target 5G ProSe End UE. More specifically, the Direct Modification Reject message (e.g., a PROSE DIRECT LINK MODIFICATION REJECT message) may include an information element such as a (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 End UE to the source 5G ProSe End 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 End UE. Furthermore, the Direct Communication Reject message (e.g., a PROSE DIRECT LINK ESTABLISHMENT REJECT message) may further include a new PC5 signaling protocol cause IE (i.e., a PC5 end UE failure cause IE) for signaling a cause value of the target 5G ProSe End UE. The new PC5 signaling protocol cause IE may be optional and may be included if the (existing) PC5 signaling protocol cause IE indicates a rejection by the target 5G ProSe End UE. The new PC5 signaling protocol cause IE may include one or more cause values ​​(e.g., the value X shown in FIG. 11) for indicating a rejection cause of the target 5G ProSe End UE, similar to the cause values ​​indicating a rejection cause by the 5G ProSe UE-to-UE Relay.

[0245] As mentioned above, the Direct Modification Reject message may further include identification information indicating the target node (i.e., the target end UE information shown in step 6), and may indicate the user information ID of the target 5G ProSe End UE with which the source 5G ProSe End UE is attempting to perform 5G ProSe Communication, among multiple target 5G ProSe End UEs.

[0246] In response to receiving the Direct Modification Reject message from the 5G ProSe UE-to-UE Relay, the source 5G ProSe End UE may determine a next step (step 7) based on the indication of rejection by the target 5G ProSe End 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 step in step 7 may include procedures corresponding to block 930 of FIG. 9.

[0247] FIG. 12 illustrates a method 1200 of relayed connections between nodes according to some embodiments.

[0248] Method 1200 is performed by a source node such as a user device (e.g., user equipment (UE)) or by an apparatus used in the source node (e.g., source 5G ProSe End UE) as described above. The relay node and target node may each be a user device (e.g., user equipment (UE)) or an apparatus used in the user device (e.g., 5G ProSe UE-to-UE Relay and target 5G ProSe End UE, respectively), as described above.

[0249] In method 1200, the relay node has an established connection to the target node (i.e., an existing connection at the second hop). For example, the existing connection to the relay node may have been established as a result of performing methods 600 and 700 described above.

[0250] In block 1210, the source node sends a communication request message to the relay node to establish 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 an (indirect) connection from the source node to the target node via the relay node by establishing a direct connection (i.e., first hop) between the source node and the relay node and modifying an existing direct connection (i.e., second hop) between the relay node and the target node.

[0251] In some examples, the communication request message to establish a connection includes a PROSE DIRECT LINK ESTABLISHMENT REQUEST message.

[0252] In block 1220, the source node receives a communication refusal message from the relay node indicating a refusal to establish a connection between the source node and the relay node due to a refusal to modify the existing connection between the relay node and the target node. With the communication refusal message, the relay node indicates to, and thus notifies, the source node that the target node has refused to modify the existing connection between the relay node and the target node. In other words, the second hop was not modified due to a failure or refusal to modify the existing connection.

[0253] In some examples, the communication refusal message indicating the refusal to establish a connection includes a PROSE DIRECT LINK ESTABLISHMENT REJECT message.

[0254] The indication of refusal to establish a connection between a source node and a relay node due to a refusal to modify an existing connection between the relay node and the target node corresponds to the indication of refusal to establish a connection by the target node, as described above in connection with Figure 6. Therefore, a repetition of details will be omitted here.

[0255] In some examples, if the source node receives a communication refusal message indicating 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 (block 1220), the source node may implement a procedure to handle or address the refusal by the target node (block 1230). Examples of such a procedure are described above in connection with block 630 of FIG. 6.

[0256] In method 1200, the source node is notified that the denial is due to a denial, caused by the target node, to the establishment of a connection (ie, second hop) between the relay node and the target node.

[0257] FIG. 13 illustrates a method 1300 of relayed connections between nodes according to some embodiments.

[0258] Method 1300 is performed by a relay node such as a user device (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 target node may each be a user device (e.g., user equipment (UE)) or an apparatus used in the user device (e.g., source 5G ProSe End UE and target 5G ProSe End UE, respectively), as described above.

[0259] In method 1200, the relay node has an established connection to the target node (i.e., an existing connection at the second hop). For example, the existing connection to the relay node may have been established as a result of performing methods 600 and 700 described above.

[0260] In block 1310, the relay node receives a communication request message from the source node to establish 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 an (indirect) connection from the source node to the target node via the relay node by establishing a direct connection (i.e., first hop) between the source node and the relay node and modifying the existing direct connection (i.e., second hop) between the relay node and the target node.

[0261] In some examples, the communication request message to establish a connection includes a PROSE DIRECT LINK ESTABLISHMENT REQUEST message.

[0262] In block 1320, the relay node modifies or attempts to modify the existing connection (i.e., the second hop) to the target node. More specifically, the relay node performs a procedure to modify the existing connection to the target node. For example, the relay node may send a communication request message (e.g., a PROSE DIRECT LINK MODIFICATION REQUEST message) to modify the existing connection to the target node, and modify the existing connection between the relay node and the target node by receiving a communication accept message (e.g., a PROSE DIRECT LINK MODIFICATION ACCEPT message) from the target node, or a communication rejection message (e.g., a PROSE DIRECT LINK MODIFICATION REJECT message) indicating the target node's refusal to modify the existing connection.

[0263] If the relay node receives a communication refusal message (i.e., a refusal by the target node to modify the existing connection), the relay node sends a communication refusal message to the source node that requested establishment of communication to the target node through the relay node indicating the refusal to establish a connection between the source node and the relay node due to the refusal to modify the existing connection between the relay node and the target node (block 1330). With this communication refusal message, the relay node indicates to the source node that the target node has refused to modify the existing direct connection, thereby notifying the source node. In other words, the failure or refusal to modify the existing direct connection resulted in the second hop not being modified.

[0264] In some examples, the communication rejection message indicating a rejection to establishment of a connection between the source node and the relay node due to a rejection to modification of an existing connection between the relay node and the target node comprises a PROSE DIRECT LINK ESTABLISHMENT REJECT message.

[0265] Details regarding the refusal instruction in the communication refusal message are described above in connection with Figure 6. Therefore, a repetition of details will be omitted here.

[0266] In some examples, multiple source devices may be attempting to connect to or connected to a target node. In such examples, a communication rejection message indicating a rejection of establishment of a connection between a source node and a relay node due to a rejection of modification of an existing connection between the relay node and the target node includes identification information indicating a source node, among multiple source devices, that requested establishment of a connection to the target node. Based on the identification information, the relay node may derive a source node that is attempting to connect to the target node and to which the communication rejection message should be sent. That is, the source node may derive the identity of the target node. In some examples, the communication rejection message may include source end UE information indicating a user information ID of the source node (i.e., source 5G ProSe End UE) when a rejection of the modification procedure occurs in the second hop. This allows the relay node to know which connection (i.e., which source 5G ProSe End UE) was rejected in the first hop when there are multiple source nodes attempting to establish a connection with the same target node.

[0267] Figure 14 shows an example message sequence diagram corresponding to a method of relayed connection between nodes according to some embodiments of the present disclosure, as described above with respect to Figures 12 and 13. More specifically, the example message sequence diagram of Figure 14 relates to 5G ProSe Communication over 5G ProSe UE-to-UE Relay using a Direct Link Modification procedure at the second hop in case of failure / rejection by the target node (e.g., target 5G ProSe End UE).

[0268] The 5G ProSe UE-to-UE Relay and the target 5G ProSe End UE have an existing connection, for example, resulting from the execution of the link establishment procedure described above.

[0269] Steps 1 and 2 shown in Figure 11 correspond to steps 1 and 2 in Figure 5. Therefore, to avoid repetition, detailed descriptions will be omitted here.

[0270] In step 3, the source 5G ProSe End 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 to establish a connection to the relay node (i.e., block 1210 in FIG. 12 and block 1310 in FIG. 13).

[0271] For example, the Direct Communication Request message may include a PROSE DIRECT LINK ESTABLISHMENT REQUEST message.

[0272] 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 End UE (step 4). The Direct Modification Request message causes the relay node to attempt to modify the existing connection to the target node (i.e., block 1320 of FIG. 13).

[0273] For example, the Direct Modification Request message may include a PROSE DIRECT LINK MODIFICATION REQUEST message.

[0274] The link modification procedure may fail due to a failure or rejection by the target 5G ProSe End UE, and the target 5G ProSe End 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 End UE. For example, the Direct Modification Reject message (e.g., a PROSE DIRECT LINK MODIFICATION REJECT message) may include an information element such as a PC5 signaling protocol cause IE used to signal a cause value. The PC5 signaling protocol cause IE may include a cause value (i.e., one or more cause values) that indicates the cause of the rejection of the target 5G ProSe End UE (e.g., the value X shown in FIG. 14).

[0275] As mentioned above, the Direct Modification Reject message may further include identification information indicating the source node (i.e., the source end UE information shown in step 5) to indicate the user information ID of the source 5G ProSe End UE when multiple source 5G ProSe End UEs are attempting to perform 5G ProSe Communication with the target 5G ProSe End UE.

[0276] In response to receiving the Direct Modification Reject message from the target 5G ProSe End UE, the 5G ProSe UE-to-UE Relay sends a Direct Communication Reject message to the source 5G ProSe End UE (step 6). Step 6 corresponds to sending a communication rejection message indicating a rejection to the establishment of a connection between the source node and the relay node due to a rejection to the modification of the existing connection between the relay node and the target node (i.e., block 1220 of FIG. 12 and block 1330 of FIG. 13). The Direct Communication Reject message may include an indication of the rejection by the target 5G ProSe End UE.

[0277] For example, the Direct Communication Reject message may include a PROSE DIRECT LINK ESTABLISHMENT REJECT message indicating a failure from the target 5G ProSe End UE. More specifically, the Direct Modification Reject message (e.g., a PROSE DIRECT LINK ESTABLISHMENT REJECT message) may include a (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 End UE to the source 5G ProSe End 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 End UE. Furthermore, the Direct Communication Reject message (e.g., a PROSE DIRECT LINK ESTABLISHMENT REJECT message) may further include a new PC5 signaling protocol cause IE (i.e., a PC5 end UE failure cause IE) for signaling a cause value of the target 5G ProSe End UE. The new PC5 signaling protocol cause IE may be optional and may be included when the (existing) PC5 signaling protocol cause IE indicates a rejection by the target 5G ProSe End UE. The new PC5 signaling protocol cause IE includes one or more cause values ​​(e.g., the value X shown in FIG. 14) for indicating a rejection cause of the target 5G ProSe End UE, similar to the cause values ​​indicating the rejection cause of the 5G ProSe UE-to-UE Relay described above.

[0278] In response to receiving the Direct Communication Reject message from the 5G ProSe UE-to-UE Relay, the source 5G ProSe End UE may determine a next step (step 7) based on the indication of rejection by the target 5G ProSe End 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 step in step 7 may include procedures corresponding to block 1230 of FIG. 12.

[0279] In some example methods of relayed connections between the nodes described above, the connection to the target node may be established via multiple relay nodes (i.e., two or more 5G ProSe UE-to-UE Relays) (referred to herein as a multi-hop scenario). For example, the established connection may include a first (direct) connection between the source node and a first relay node (e.g., a relay node 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. To establish a connection between the source node and the target node, a (direct) connection between the nodes may be established if it does not already exist, or a (direct) connection may be modified if it already exists. To provide the source node with an indication of which (intermediate) relay nodes rejected the establishment / modification of the connection, the communication rejection message received at the source node includes an indication of the (intermediate) relay nodes that caused the rejection of the establishment of the connection to the target node. For example, the (existing) information element in the communication rejection message may include one or more cause values ​​indicating that the rejection was due to a rejection by a (intermediate) relay node. Additionally or alternatively, the communication rejection message may include additional information elements for signaling one or more cause values ​​of the (intermediate) relay nodes.

[0280] 15 illustrates an example message sequence diagram corresponding to a method for relaying a connection between nodes according to some embodiments of the present disclosure. More specifically, the example message sequence diagram of FIG. 15 relates to the multi-hop scenario described above in case of failure / rejection by an (intermediate) relay node (e.g., 5G ProSe End UE-to-UE Relay 3).

[0281] As shown in FIG. 15, a connection from a source node (i.e., source 5G ProSe End UE) to a target node (i.e., target 5G ProSe End UE) is established via multiple relay nodes (i.e., 5G ProSe End UE-to-UE Relay1-3).

[0282] In step 1, the source 5G ProSe End UE sends a Direct Communication Request message to initiate a link establishment procedure with the 5G ProSe UE-to-UE Relay 1. The Direct Communication Request message sent in step 1 corresponds to the communication request message for establishing a connection to the target node via the relay node described in connection with block 610 of FIG. 6 and block 710 of FIG. 7 .

[0283] In response to receiving the Direct Communication Request message, 5G ProSe UE-to-UE Relay1 transmits a Direct Communication Request message to start a link establishment procedure with 5G ProSe UE-to-UE Relay2 (step 2). In response to receiving the Direct Communication Request message, 5G ProSe UE-to-UE Relay2 transmits a Direct Communication Request message to start a link establishment procedure with 5G ProSe UE-to-UE Relay3 (step 2). The Direct Communication Request messages transmitted in steps 2 and 3 cause the relay nodes to initiate a procedure for establishing a direct connection between the relay nodes.

[0284] The link establishment procedure may fail due to a failure or 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., a PROSE DIRECT LINK ESTABLISHMENT REJECT message) may include an information element such as a PC5 signaling protocol cause IE used to signal a cause value. The PC5 signaling protocol cause IE may include a cause value (i.e., one or more cause values) that indicates the rejection cause of the 5G ProSe UE-to-UE Relay 3 (e.g., the value X shown in FIG. 15).

[0285] In response to receiving the Direct Communication Reject message from the 5G ProSe UE-to-UE Relay 3, the 5G ProSe UE-to-UE Relay 2 may determine a next step (step 4a) based on an indication of rejection 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 step in step 4a may include the procedure described above with respect to block 630 of FIG. 6. For example, the 5G ProSe UE-to-UE Relay 2 may be a device for finding another 5G ProSe UE-to-UE Relay and retrying to establish a connection to the other 5G ProSe UE-to-UE Relay 3.

[0286] In response to receiving the Direct Communication Reject message from 5G ProSe UE-to-UE Relay 3, 5G ProSe UE-to-UE Relay 2 sends a Direct Communication Reject message to 5G ProSe UE-to-UE Relay 1 (step 5). The Direct Communication Reject message includes an indication of rejection by 5G ProSe UE-to-UE Relay 3. In other words, 5G ProSe UE-to-UE Relay 2 transmits an indication of rejection by 5G ProSe UE-to-UE Relay 3 to 5G ProSe UE-to-UE Relay 1.

[0287] For example, the Direct Communication Reject message may include a PROSE DIRECT LINK ESTABLISHMENT REJECT message indicating a failure from 5G ProSe UE-to-UE Relay 3. More specifically, the Direct Modification Reject message (e.g., a PROSE DIRECT LINK ESTABLISHMENT REJECT message) may include an information element such as 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 a rejection by 5G ProSe UE-to-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 5G ProSe UE-to-UE Relay 3 (i.e., a failure at the UE-to-UE Relay). Furthermore, the Direct Communication Reject message (e.g., a PROSE DIRECT LINK ESTABLISHMENT REJECT message) may further include a new PC5 signaling protocol cause IE (i.e., an intermediate PC5 signaling protocol cause IE) for signaling a cause value of an (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 be included when the (existing) PC5 signaling protocol cause IE indicates a 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., the value X shown in FIG. 15 ) indicating a rejection cause of the (intermediate) 5G ProSe UE-to-UE Relay 3, similar to the cause values ​​indicating the rejection cause of the 5G ProSe UE-to-UE Relay.

[0288] In some examples, the Direct Communication Reject message may further include identification information (i.e., relay UE information) that indicates to the relay node to indicate a user information ID of an (intermediate) 5G ProSe UE-to-UE Relay 3 involved in relaying the connection from the source 5G ProSe End UE to the target 5G ProSe End UE among multiple 5G ProSe UE-to-UE Relays.

[0289] In response to receiving the Direct Communication Reject message from 5G ProSe UE-to-UE Relay 2, 5G ProSe UE-to-UE Relay 1 sends a Direct Communication Reject message to the source 5G ProSe End UE (step 6). The Direct Communication Reject message includes an indication of rejection by 5G ProSe UE-to-UE Relay 3. In other words, 5G ProSe UE-to-UE Relay 1 transmits an indication of rejection by 5G ProSe UE-to-UE Relay 3 to the source 5G ProSe End UE.

[0290] In response to receiving the Direct Communication Reject message from 5G ProSe UE-to-UE Relay 1, the source 5G ProSe End UE may determine a next step (step 7) based on the indication of rejection (e.g., one or more cause values ​​provided in the existing PC5 signaling protocol cause IE and the intermediate PC5 signaling protocol cause IE) by 5G ProSe UE-to-UE Relay 3. The next step in step 7 may include the procedure described above with respect to block 630 of FIG.

[0291] It should be understood that in the example message sequence diagram of FIG. 15, existing connections between nodes may exist such that instead of establishing a (new) connection, a procedure may be performed to modify such an existing connection.

[0292] It should be understood that the apparatus may comprise or be coupled to other units or modules, such as radio components or radio heads used in or for transmission and / or reception. Although the apparatus is described as one entity, the different modules and memories may be implemented in one or more physical or logical entities.

[0293] It should be noted that although the embodiments are described in the context of LTE and 5G NR, similar principles are applicable in the context of other networks and communication systems where fast connection re-establishment is required to be performed. Thus, although certain embodiments are described above by way of example with respect to certain exemplary architectures, technologies, and standards of wireless networks, the embodiments may be applied to any other suitable forms of communication systems other than those shown and described herein.

[0294] Also, it should be noted that although the above describes exemplary embodiments herein, there are several variations and modifications that can be made to the disclosed solutions without departing from the scope of the present disclosure.

[0295] In general, various exemplary embodiments may be implemented in hardware or special purpose circuits, software, logic, or any combination thereof. Some aspects of the present disclosure may be implemented in hardware, and other aspects may be implemented in firmware or software that may be executed by a controller, microprocessor, or other computing device, although the present disclosure is not limited thereto. While various aspects of the present disclosure may be shown and described as block diagrams, flowcharts, or using some other graphical representation, it should be appreciated that these blocks, apparatus, systems, techniques, or methods described herein may be implemented in, by way of non-limiting example, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller, or other computing device, or some combination thereof.

[0296] Exemplary 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 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 on any device-readable data storage medium and include program instructions for performing specific tasks. A computer program product may comprise one or more computer-executable components configured to perform an embodiment when the program is executed. The one or more computer-executable components may be at least one software code or a portion thereof.

[0297] Further, in this regard, it should be noted that any block of logic flow as shown in the figures may represent a program step, or interconnected logic circuits, blocks, and functions, or a combination of program steps and logic circuits, blocks, and functions. Software may be stored on physical media, such as memory chips or memory blocks implemented within a processor, magnetic media such as hard disks or floppy disks, and optical media, e.g., DVDs and their data variants, CDs, etc. Physical media are non-transitory media.

[0298] The memory may be of any type suitable for the local technology 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 technology environment and may include, by way of non-limiting examples, one or more of 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.

[0299] Exemplary embodiments of the present disclosure may be practiced in a variety of components, such as integrated circuit modules. Integrated circuit design is generally a highly automated process. Complex and powerful software tools are available to convert logic-level designs into semiconductor circuit designs ready to be etched and formed on semiconductor substrates.

[0300] The foregoing description provides a complete and informative description of exemplary embodiments of the present disclosure, by way of non-limiting example. However, various modifications and adaptations may become apparent to those skilled in the art in light of the foregoing description, when read in conjunction with the accompanying drawings and the appended claims. However, all such and similar modifications of the teachings of this invention will still fall within the scope of the present disclosure, as defined by the appended claims. In fact, further embodiments exist that include combinations of one or more of the embodiments with any of the other embodiments discussed above.

Claims

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

2. 1. A method for relaying connections between nodes, comprising: receiving a communication request message from a source node at a relay node for establishing a connection to a target node via the relay node; Establishing a connection to a target node; In response to receiving the refusal by the target node to establish the connection, transmitting a communication refusal message from the relay node to the source node indicating the refusal by the target node to establish the connection; Including, the communication rejection message includes one or more cause values ​​indicating that the rejection is due to a rejection by the target node; The method, wherein the communication rejection message includes an additional information element for signaling a cause value of the target node.

3. An apparatus at a source node, comprising: at least one processor; at least one memory containing computer program code that, when executed by at least one processor, causes the apparatus to: sending a communication request message to the relay node to establish a connection to the target node via the relay node; receiving a communication refusal message from the relay node indicating a refusal by the target node to establish a connection; at least one memory for causing Equipped with the communication rejection message includes one or more cause values ​​indicating that the rejection is due to a rejection by the target node; The communication rejection message includes an additional information element for signaling a cause value of the target node.

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

5. The computer program code, when executed by at least one processor, causes the apparatus to: starting a timer in response to receiving the communication refusal message; transmitting another communication request message in response to the timer elapsed; The apparatus of claim 4 further comprising:

6. The computer program code, when executed by at least one processor, causes the apparatus to: In response to receiving the communication rejection message, performing a relay reselection procedure to select another relay node; sending a communication request message to another relay node to establish a connection to the target node via the other relay node; The apparatus according to any one of claims 3 to 5, further comprising:

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

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

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

10. 10. The device according to claim 8 or 9, wherein the communication refusal message indicating a refusal to modify the connection includes identification information indicating the source node and / or identification information indicating the target node.

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

12. 12. The apparatus of claim 8, wherein the communication request message to modify the connection comprises a PROXIMITY SERVICE, PROSE, DIRECT LINK MODIFICATION REQUEST message, and / or the communication rejection message indicating a rejection to modify the connection comprises a PROSE DIRECT LINK MODIFICATION REJECT message.

13. 13. The apparatus of claim 3, wherein the communication rejection message indicates a rejection by one or more second relay nodes through which the source node connects to the target node.

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

15. 15. The apparatus of claim 14, wherein the communication rejection message includes an additional information element for signaling a cause value of the second relay node.

16. 1. An apparatus at a relay node, comprising: at least one processor; at least one memory containing computer program code that, when executed by at least one processor, causes the apparatus to: receiving a communication request message from a source node to establish a connection to a target node via a relay node; Establishing a connection to a target node; in response to receiving the refusal by the target node to establish the connection, transmitting a communication refusal message to the source node indicating the refusal by the target node to establish the connection; at least one memory for causing Equipped with the communication rejection message includes one or more cause values ​​indicating that the rejection is due to a rejection by the target node; The communication rejection message includes an additional information element for signaling a cause value of the target node.

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

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

19. 18. The device according to claim 16 or 17, wherein the communication refusal message indicating a refusal to modify the connection comprises identification information indicating the source node and / or identification information indicating the target node.

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

21. 21. The apparatus of claim 16, wherein the communication rejection message indicates a rejection by one or more second relay nodes through which the source node connects to the target node.

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

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

24. The computer program code, when executed by at least one processor, causes the apparatus to: In response to receiving the rejection by one or more second relay nodes, performing a relay reselection procedure to select another second relay node; establishing a connection to the target node via another second relay node; 24. The apparatus of claim 21, further comprising:

25. A computer program product comprising program instructions stored on a computer readable medium, said program performing the method of claim 1 or 2 when said program is run on a computer.

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