Method, apparatus and computer program

Abstract

There is provided an apparatus comprising means for determining a communication request associated with relay discovery and selection for user equipment-to-network (U2N) relay connection establishment for a first user equipment (UE), and means for relaying the UE via at least one first user equipment-to-user equipment (U2U) based on the communication request, means for providing a communication request to the U2N relay UE using a relay chain established between the U2N relay UE and the second UE via the at least one first U2U relay UE.

Description

Technical Field

[0001] Various examples of the present disclosure relate to methods, apparatus, and computer programs for wireless communication systems. Background Art

[0002] A communication system may be a facility for enabling communication sessions between two or more entities (e.g., user terminals, base stations / access points, and / or other nodes) by providing a carrier between the various entities involved in the communication path. A communication system may be provided, for example, by a communication network and one or more compatible communication devices. A communication session may include data communications for carrying communications such as voice, email, text messages, multimedia, and / or content data. Some examples of the services provided include two-way or multi-way calls, data communications or multimedia services, and access to data network systems (e.g., the Internet). Summary of the invention

[0003] Some examples of the present disclosure are described for certain aspects. These aspects are not intended to indicate the key or essential features of the various examples, nor are they intended to be used to limit their scope. In view of the present disclosure, other features, aspects and elements will be easily understood by those skilled in the art. For example, it should be understood that further aspects can be provided by combining any two or more of the various aspects described below.

[0004] According to one aspect, an apparatus is provided, comprising: a means for determining a communication request associated with relay discovery and selection for establishing a user equipment to network (U2N) relay connection for a first user equipment (UE); and a means for providing the communication request to the U2N relay UE via at least one first user equipment to user equipment (U2U) relay UE, based on the communication request, using a relay chain established between the U2N relay UE and a second UE via the at least one first U2U relay UE.

[0005] In some examples, at least one of the first UE or the second UE is out--of--coverage of a serving cell.

[0006] In some examples, the communication request is a direct communication request.In an example, the first UE and the second UE are respectively remote UEs.

[0007] In some examples, the communication request associated with relay discovery and selection is associated with a U2N relay UE via at least one U2U relay UE, wherein the communication request is a request for a connection between the first UE and the U2N relay UE via the at least one U2U relay UE. In an example, the communication request includes information instructing the relay discovery and selection of the U2N relay UE to use the established relay chain.

[0008] In some examples, the component for determining the communication request includes one of: a component for receiving the communication request from at least one of the first user equipment or at least one second U2U relay UE, or a component for initiating the communication request.

[0009] In some examples, the communication request includes information associated with relay selection indicating that the established relay chain includes at least an identification of the U2N relay UE.

[0010] In some examples, the device includes: a component for determining whether the communication request includes information associated with relay selection; a component for selecting the U2N relay UE to use the established relay chain based on the information associated with relay selection when it is determined that the communication request includes information associated with relay selection; and a component for retrieving first information associated with relay selection from the established relay chain and inserting the first information into the communication request when it is determined that the communication request does not include information associated with relay selection, wherein the first information includes information indicating that the established relay chain includes at least the identification of the U2N relay UE.

[0011] In some examples, the established relay chain is part of a multi-hop user equipment to network relay connection of the second UE served by the U2N relay UE and at least one U2U relay UE including the at least one first U2U relay UE.

[0012] In some examples, the apparatus includes: a component for receiving an acceptance message associated with the communication request from the U2N relay UE directly or via at least one U2U relay UE, wherein the acceptance message indicates acceptance of the communication request; and a component for providing the acceptance message to the first user equipment.

[0013] In some examples, the device includes: a component for receiving a rejection message associated with the communication request, wherein the rejection message indicates a rejection of the communication request; a component for retrieving second information associated with relay selection from another established relay chain based on receiving the rejection message, replacing the first information with the second information in the communication request, and providing the communication request to another U2N relay UE using the other established relay chain, wherein the second information includes an identifier of the other U2N relay UE.

[0014] In some examples, the rejection message is received from one of: directly from the U2N relay UE, from the U2N relay UE via at least one U2U relay UE, directly from the U2U relay in the established relay chain, or from the U2U relay UE in the established relay chain via at least one other U2U relay UE in the established relay chain.

[0015] In some examples, the communication request includes a flag, wherein the flag indicates that the information associated with relay selection in the communication request was initiated by the first UE or the U2U relay UE.

[0016] In some examples, it is one of the following: the device is used for the first UE, the device is included in the first UE, the device is the first UE, the device is used for U2U relay user equipment, the device is included in U2U relay user equipment, and the device is U2U relay user equipment.

[0017] In some examples, it is one of the following: the device is used for a U2U relay UE of the established relay chain, or the device is used for the first UE and also for a U2U relay UE of the established relay chain.

[0018] According to one aspect, an apparatus is provided, comprising: a component for initiating a communication request associated with relay discovery and selection for establishing a user equipment to network (U2N) relay connection for a first user equipment (UE), wherein the communication request is a request for a connection between the first UE and the U2N relay UE via at least one first user equipment to user equipment (U2U) relay UE, wherein the communication request indicates that the at least one first U2U relay UE is allowed to perform relay selection for the connection; and a component for providing the communication request to the at least one U2U relay UE.

[0019] In some examples, the communication request includes information associated with relay selection, the information indicating the established relay chain between the U2N relay UE and the second UE via the at least one U2U relay UE, including at least an identifier of the U2N relay UE for the connection.

[0020] In some examples, the apparatus includes means for communicating with a network using the connection established between the first UE and the U2N relay via the at least one first U2U relay UE.

[0021] In some examples, one of the following is true: the device is used for the first UE, the device is included in the first UE, and the device is the first UE.

[0022] According to one aspect, an apparatus is provided, comprising: a component for receiving a communication request associated with relay discovery and selection from a user equipment to user equipment (U2U) relay user equipment (UE), wherein the communication request is a request for a connection between a first UE and a user equipment to network (U2N) relay UE via at least one U2U relay UE, wherein the communication request indicates that the at least one U2U relay UE is allowed to perform relay selection for the connection; and a component for providing a response to the communication request to the first UE via the U2U relay UE based on the communication request.

[0023] In some examples, the component for providing a response to the communication request to the first UE via the U2U relay UE based on the communication request includes: a component for determining, based on the communication request, whether to respond using one of the following: an acceptance message associated with the communication request, a rejection message associated with the communication request, or a relay discovery message associated with the communication request; and a component for providing the response to the first UE via the U2U relay UE based on the determination.

[0024] In some examples, the acceptance message is DCA, the rejection message is DCRj, and the relay discovery message associated with the communication request is DR.

[0025] In some examples, the apparatus includes means for selecting at least one U2U relay UE based on a flag included in the communication request.

[0026] In some examples, when it is determined to provide a rejection message associated with the communication request, the apparatus includes: a component for including a rejection flag and the rejection message associated with the communication request in the response, wherein the rejection flag indicates that the rejection message is initiated by the U2N relay UE.

[0027] In some examples, when it is determined to respond using the relay discovery message associated with the communication request, the device includes a component for selecting one or more U2U relay UEs from the at least one U2U relay UE; and a component for sending the response separately to the selected one or more U2U relay UEs.

[0028] In some examples, it is one of the following: the device is used for the U2N relay UE, the device is included in the U2N relay UE, and the device is the U2N relay UE.

[0029] According to one aspect, a method is provided, comprising: determining a communication request associated with relay discovery and selection for establishing a user equipment to network (U2N) relay connection for a first user equipment (UE); and based on the communication request, providing the communication request to the U2N relay UE via at least one first user equipment to user equipment (U2U) relay UE, using an established relay chain between the U2N relay UE and a second UE via the at least one first U2U relay UE.

[0030] In some examples, at least one of the first UE or the second UE is outside the coverage of a serving cell.

[0031] In some examples, the communication request is a direct communication request.In an example, the first UE and the second UE are respectively remote UEs.

[0032] In some examples, the communication request associated with relay discovery and selection is associated with a U2N relay UE via at least one U2U relay UE, wherein the communication request is a request for a connection between the first UE and the U2N relay UE via the at least one U2U relay UE. In an example, the communication request includes information instructing the relay discovery and selection of the U2N relay UE to use the established relay chain.

[0033] In some examples, the determining the communication request includes one of: receiving the communication request from at least one of the first user equipment or at least one second U2U relay UE, or initiating the communication request.

[0034] In some examples, the communication request includes information associated with relay selection indicating an established relay chain including at least an identification of the U2N relay UE.

[0035] In some examples, the method includes: determining whether the communication request includes information associated with relay selection; when it is determined that the communication request includes information associated with relay selection, selecting the U2N relay UE to use the established relay chain based on the information associated with relay selection; when it is determined that the communication request does not include information associated with relay selection, retrieving first information associated with relay selection from the established relay chain and inserting the first information into the communication request, wherein the first information includes information indicating that the established relay chain includes at least the identification of the U2N relay UE.

[0036] In some examples, the established relay chain is part of a multi-hop user equipment to network relay connection of the second UE served by the U2N relay UE and at least one U2U relay UE including the at least one first U2U relay UE.

[0037] In some examples, the method includes: receiving an acceptance message associated with the communication request from the U2N relay UE directly or via at least one U2U relay UE, wherein the acceptance message indicates acceptance of the communication request; and providing the acceptance message to the first user equipment.

[0038] In some examples, the method includes: receiving a rejection message associated with the communication request, wherein the rejection message indicates a rejection of the communication request; based on receiving the rejection message: retrieving second information associated with relay selection from another established relay chain, wherein the second information includes an identifier of another U2N relay UE; replacing the first information with the second information in the communication request; and providing the communication request to the other U2N relay UE using the other established relay chain.

[0039] In some examples, the rejection message is received from one of: directly from the U2N relay UE, from the U2N relay UE via at least one U2U relay UE, directly from the U2U relay in the established relay chain, or from the U2U relay UE in the established relay chain via at least one other U2U relay UE in the established relay chain.

[0040] In some examples, the communication request includes a flag, wherein the flag indicates that the information associated with relay selection in the communication request was initiated by the first UE or the U2U relay UE.

[0041] In some examples, the method is performed by the first UE or U2U relay user equipment.

[0042] In some examples, the method is performed by a U2U relay UE of the established relay chain, or by the first UE that is also configured as a U2U relay UE of the established relay chain.

[0043] According to one aspect, a method is provided, comprising: initiating a communication request associated with relay discovery and selection for establishing a user equipment to network (U2N) relay connection for a first user equipment (UE), wherein the communication request is a request for a connection between the first UE and the U2N relay UE via at least one first user equipment to user equipment (U2U) relay UE, wherein the communication request indicates that the at least one first U2U relay UE is allowed to perform relay selection for the connection; and providing the communication request to the at least one U2U relay UE.

[0044] In some examples, the communication request includes information associated with relay selection, the information indicating the established relay chain between the U2N relay UE and the second UE via the at least one U2U relay UE, including at least an identifier of the U2N relay UE for the connection.

[0045] In some examples, the method includes communicating with a network using the connection established between the first UE and the U2N relay via the at least one first U2U relay UE.

[0046] In some embodiments, the method is performed by the first UE.

[0047] According to one aspect, a method is provided, comprising: receiving a communication request associated with relay discovery and selection from a user equipment to user equipment (U2U) relay user equipment (UE), wherein the communication request is a request for a connection between a first UE and a user equipment to network (U2N) relay UE via at least one U2U relay UE, wherein the communication request indicates that the at least one U2U relay UE is allowed to perform relay selection for the connection; and providing a response to the communication request to the first UE via the U2U relay UE based on the communication request.

[0048] In some examples, providing a response to the communication request to the first UE via the U2U relay UE includes: determining, based on the communication request, whether to respond using one of the following: an acceptance message associated with the communication request, a rejection message associated with the communication request, or a relay discovery message associated with the communication request; and providing the response to the first UE via the U2U relay UE based on the determination.

[0049] In some examples, the acceptance message is DCA, the rejection message is DCRj, and the relay discovery message associated with the communication request is DR.

[0050] In some examples, the method includes selecting at least one U2U relay UE based on a flag included in the communication request.

[0051] In some examples, when it is determined to provide a rejection message associated with the communication request, the method includes: including a rejection flag together with the rejection message associated with the communication request in the response, wherein the rejection flag indicates that the rejection message is initiated by the U2N relay UE.

[0052] In some examples, when determining to respond using the relay discovery message associated with the communication request, the method includes: selecting one or more U2U relay UEs from the at least one U2U relay UE; and sending the response separately to the selected one or more U2U relay UEs.

[0053] In some examples, the method is performed by a U2N relay UE.

[0054] According to one aspect, a device is provided, comprising: at least one processor, and at least one memory storing instructions, wherein the instructions, when executed by the at least one processor, cause the device to perform: determining a communication request associated with relay discovery and selection for establishing a user equipment to network (U2N) relay connection for a first user equipment (UE); and based on the communication request, providing the communication request to the U2N relay UE via at least one first user equipment to user equipment (U2U) relay UE, using a relay chain established between the U2N relay UE and a second UE via the at least one first U2U relay UE.

[0055] In some examples, at least one of the first UE or the second UE is outside the coverage of a serving cell.

[0056] In some examples, the communication request is a direct communication request.In an example, the first UE and the second UE are respectively remote UEs.

[0057] In some examples, the communication request associated with relay discovery and selection is associated with a U2N relay UE via at least one U2U relay UE, wherein the communication request is a request for a connection between the first UE and the U2N relay UE via the at least one U2U relay UE. In an example, the communication request includes information instructing the relay discovery and selection of the U2N relay UE to use the established relay chain.

[0058] In some examples, the determining the communication request includes one of: receiving the communication request from at least one of the first user equipment or at least one second U2U relay UE, or initiating the communication request.

[0059] In some examples, the communication request includes information associated with relay selection indicating that the established relay chain includes at least an identification of the U2N relay UE.

[0060] In some examples, the device is caused to perform: determining whether the communication request includes information associated with relay selection; when it is determined that the communication request includes information associated with relay selection, selecting the U2N relay UE to use the established relay chain based on the information associated with relay selection; when it is determined that the communication request does not include information associated with relay selection: retrieving first information associated with relay selection from the established relay chain and inserting the first information into the communication request, wherein the first information includes information indicating that the established relay chain includes at least the identifier of the U2N relay UE.

[0061] In some examples, the established relay chain is part of a multi-hop user equipment to network relay connection of the second UE served by the U2N relay UE and at least one U2U relay UE including the at least one first U2U relay UE.

[0062] In some examples, the apparatus is caused to perform: receiving an acceptance message associated with the communication request from the U2N relay UE directly or via at least one U2U relay UE, wherein the acceptance message indicates acceptance of the communication request; and providing the acceptance message to the first user equipment.

[0063] In some examples, the device is caused to perform: receiving a rejection message associated with the communication request, wherein the rejection message indicates a rejection of the communication request; based on receiving the rejection message: retrieving second information associated with relay selection from another established relay chain, wherein the second information includes an identifier of another U2N relay UE; replacing the first information with the second information in the communication request, and providing the communication request to the other U2N relay UE using the other established relay chain.

[0064] In some examples, the rejection message is received from one of: directly from the U2N relay UE, from the U2N relay UE via at least one U2U relay UE, directly from the U2U relay in the established relay chain, or from the U2U relay UE in the established relay chain via at least one other U2U relay UE in the established relay chain.

[0065] In some examples, the communication request includes a flag, wherein the flag indicates whether the information associated with relay selection in the communication request is initiated by the first UE or the U2U relay UE.

[0066] In some examples, it is one of the following: the device is used for the first UE, the device is included in the first UE, the device is the first UE, the device is used for U2U relay user equipment, the device is included in U2U relay user equipment, and the device is U2U relay user equipment.

[0067] In some examples, it is one of the following: the device is used for a U2U relay UE of the established relay chain, or the device is used for the first UE and also for a U2U relay UE of the established relay chain.

[0068] According to one aspect, a device is provided, comprising: at least one processor, and at least one memory storing instructions, wherein the instructions, when executed by the at least one processor, cause the device to perform: initiating a communication request associated with relay discovery and selection for establishing a user equipment to network (U2N) relay connection for a first user equipment (UE), wherein the communication request is a request for a connection between the first UE and the U2N relay UE via at least one first user equipment to user equipment (U2U) relay UE, wherein the communication request indicates that the at least one first U2U relay UE is allowed to perform relay selection for the connection; and providing the communication request to the at least one U2U relay UE.

[0069] In some examples, the communication request includes information associated with relay selection, the information indicating the established relay chain between the U2N relay UE and the second UE through the at least one U2U relay UE, including at least an identifier of the U2N relay UE for the connection.

[0070] In some examples, the apparatus is caused to perform: communicating with a network using the connection established between the first UE and the U2N relay via the at least one first U2U relay UE.

[0071] In some examples, one of the following is true: the device is used for the first UE, the device is included in the first UE, and the device is the first UE.

[0072] According to one aspect, a device is provided, comprising: at least one processor, and at least one memory storing instructions, wherein the instructions, when executed by the at least one processor, cause the device to perform: receiving a communication request associated with relay discovery and selection from a user equipment to user equipment (U2U) relay user equipment (UE), wherein the communication request is a request for a connection between a first UE and a user equipment to network (U2N) relay UE via at least one U2U relay UE, wherein the communication request indicates that the at least one U2U relay UE is allowed to perform relay selection for the connection; and providing a response to the communication request to the first UE via the U2U relay UE based on the communication request.

[0073] In some examples, providing a response to the communication request to the first UE via the U2U relay UE includes: determining, based on the communication request, whether to respond using one of: an acceptance message associated with the communication request, a rejection message associated with the communication request, or a relay discovery message associated with the communication request; and providing the response to the first UE via the U2U relay UE based on the determination.

[0074] In some examples, the acceptance message is DCA, the rejection message is DCRj, and the relay discovery message associated with the communication request is DR.

[0075] In some examples, the apparatus is caused to perform: selecting at least one U2U relay UE based on a flag included in the communication request.

[0076] In some examples, when it is determined to provide a rejection message associated with the communication request, the device is caused to execute: including a rejection flag together with the rejection message associated with the communication request in the response, wherein the rejection flag indicates that the rejection message is initiated by the U2N relay UE.

[0077] In some examples, when it is determined to respond using the relay discovery message associated with the communication request, the device is caused to execute: selecting one or more U2U relay UEs from the at least one U2U relay UE; and sending the response separately to the selected one or more U2U relay UEs.

[0078] In some examples, it is one of the following: the device is used for the U2N relay UE, the device is included in the U2N relay UE, and the device is the U2N relay UE.

[0079] According to one aspect, a computer program is provided comprising instructions which, when executed by an apparatus, cause the apparatus to perform at least the following: determine a communication request associated with relay discovery and selection for establishing a user equipment to network (U2N) relay connection for a first user equipment (UE); and based on the communication request, provide the communication request to the U2N relay UE via at least one first user equipment to user equipment (U2U) relay UE, using an established relay chain between the U2N relay UE and a second UE via the at least one first U2U relay UE.

[0080] According to one aspect, a computer program is provided comprising instructions, which, when executed by an apparatus, cause the apparatus to perform at least the following items: initiating a communication request associated with relay discovery and selection for establishing a user equipment to network (U2N) relay connection for a first user equipment (UE), wherein the communication request is a request for a connection between the first UE and the U2N relay UE via at least one first user equipment to user equipment (U2U) relay UE, wherein the communication request indicates that the at least one first U2U relay UE is allowed to perform relay selection for the connection; and providing the communication request to the at least one U2U relay UE.

[0081] According to one aspect, a computer program is provided comprising instructions, which when executed by an apparatus cause the apparatus to perform at least the following items: receiving a communication request associated with relay discovery and selection from a user equipment to user equipment (U2U) relay user equipment (UE), wherein the communication request is a request for a connection between a first UE and a user equipment to network (U2N) relay UE via at least one U2U relay UE, wherein the communication request indicates that the at least one U2U relay UE is allowed to perform relay selection for the connection; and providing a response to the communication request to the first UE via the U2U relay UE based on the communication request.

[0082] According to one aspect, a device is provided, comprising a circuit configured to perform the following operations: determine a communication request associated with relay discovery and selection for establishing a user equipment to network (U2N) relay connection for a first user equipment (UE); and a circuit configured to perform the following operations: based on the communication request, provide the communication request to the U2N relay UE via at least one first user equipment to user equipment (U2U) relay UE, using a relay chain established between the U2N relay UE and a second UE via the at least one first U2U relay UE.

[0083] According to one aspect, an apparatus is provided, comprising a circuit configured to perform the following operations: initiating a communication request associated with relay discovery and selection for establishing a user equipment to network (U2N) relay connection for a first user equipment (UE), wherein the communication request is a request for a connection between the first UE and the U2N relay UE via at least one first user equipment to user equipment (U2U) relay UE, wherein the communication request indicates that the at least one first U2U relay UE is allowed to perform relay selection for the connection; and a circuit configured to perform the following operations: providing the communication request to the at least one U2U relay UE.

[0084] According to one aspect, an apparatus is provided, comprising circuitry configured to: receive a communication request associated with relay discovery and selection from a user equipment to user equipment (U2U) relay user equipment (UE), wherein the communication request is a request for connection between a first UE and a user equipment to network (U2N) relay UE via at least one U2U relay UE, wherein the communication request indicates that the at least one U2U relay UE is allowed to perform relay selection for the connection; and circuitry configured to: provide a response to the communication request to the first UE via the U2U relay UE based on the communication request. A computer product stored on a medium enables an apparatus to perform the method described herein.

[0085] A non-transitory computer readable medium comprising program instructions which, when executed by an apparatus, cause the apparatus to perform the method described herein.

[0086] An electronic device may include the apparatus described herein.

[0087] In the above, various aspects are described. Various other aspects and further examples are described in the following detailed description and claims.

[0088] According to some aspects, the subject matter of the independent claims is provided. Some further aspects are defined in the dependent claims. Embodiments that do not fall within the scope of the claims should be interpreted as examples that aid in understanding the disclosure.

[0089] List of abbreviations:

[0090] AF: Application Function

[0091] AMF: Access and Mobility Management Function

[0092] AN: Access Network

[0093] BS: Base Station

[0094] CN: Core Network

[0095] DL: Downlink

[0096] DCA: Direct Communications Acceptance

[0097] DCR: Direct Communication Request

[0098] DCRj: Direct Communication Rejection

[0099] DR: Discovery Response

[0100] DS: Discovery Request

[0101] eNB: eNode B

[0102] E2E: End to End

[0103] gNB: gNode B

[0104] IC: Covered

[0105] IIoT: Industrial Internet of Things

[0106] LTE: Long Term Evolution

[0107] NEF: Network Open Function

[0108] NG--RAN: Next Generation Radio Access Network

[0109] NF:Network Function

[0110] NR: New Radio

[0111] NRF: Network Repository Function

[0112] NW:Network

[0113] MS: Mobile Station

[0114] MH: Multi-hop

[0115] OoC: Out of Coverage

[0116] PCF: Policy Control Function

[0117] PLMN: Public Land Mobile Network

[0118] RAN: Radio Access Network

[0119] RD: Relay Discovery

[0120] RF: Radio Frequency

[0121] RSRP: Reference Signal Received Power

[0122] SMF: Session Management Function

[0123] SL: Sidechain

[0124] SH: Single Hop

[0125] UE: User Equipment

[0126] UDR: Unified Data Repository

[0127] UDM: Unified Data Management

[0128] UL: Uplink

[0129] UPF: User Plane Function

[0130] Uu: The air interface between the UE and the BS (e.g., between the UE and the eNB / gNB in ​​the 3GPP standard)

[0131] U2N: UE to Network

[0132] U2U: UE to UE

[0133] 3GPP: Third Generation Partnership Project

[0134] 5G: Fifth Generation

[0135] 5GC: 5G Core Network

[0136] 5G--AN: 5G Radio Access Network

[0137] 5GS: 5G System BRIEF DESCRIPTION OF THE DRAWINGS

[0138] Some examples will now be described with reference to the accompanying drawings, in which:

[0139] Figure 1 A schematic diagram of a 5G system is shown;

[0140] Figure 2 shows a schematic diagram of the control device;

[0141] Figure 3 shows a schematic diagram of a terminal;

[0142] Figure 4 A schematic diagram of a relay chain for multi-hop sidechain communication is shown;

[0143] Figure 5 a to 5d are schematic diagrams showing different scenarios for remote user equipment;

[0144] Figure 6 shows an example signaling diagram for establishing a multi-hop relay connection;

[0145] Figure 7shows an example signaling diagram for establishing a multi-hop relay connection;

[0146] Figure 8 Another example signaling diagram for establishing a multi-hop relay connection is shown;

[0147] Fig. 9 A flow chart of an example method performed by an apparatus is shown;

[0148] Fig.10 Another example method flow chart performed by the apparatus is shown;

[0149] Fig.11 Another example method flow chart performed by the apparatus is shown; and

[0150] Fig.12 A schematic diagram of a non-volatile storage medium storing instructions that, when executed by a processor, allow the processor to perform Figures 9 to 11 One or more steps of the method described. DETAILED DESCRIPTION

[0151] In the following, various examples of the present disclosure are explained with reference to a mobile communication device capable of communicating via a wireless cellular system and a mobile communication system providing services for such mobile communication devices. Figures 1 to 3 Certain general aspects of wireless communication systems and mobile communication devices are briefly explained to aid understanding of the technology on which the described examples are based.

[0152] Figure 1 A schematic diagram of a wireless communication system 100 is shown. The wireless communication system 100 includes one or more devices 102, such as user equipment (UE) or terminals. The wireless communication system 100 includes a 5G system (5GS). The 5GS includes a 5G radio access network (5G--RAN) 106, a 5G core network (5GC) 104 including one or more network functions (NFs), one or more application functions (AFs) 108, and one or more data networks (DNs) 110 (or parts thereof).

[0153] The 5G-RAN 106 may include one or more gNodeB (gNB) distributed unit (DU) functions connected to one or more gNodeB (gNB) centralized unit (CU) functions.

[0154] 5GC 104 includes access and mobility management function (AMF) 112, session management function (SMF) 114, authentication server function (AUSF) 116, user data management (UDM) 118, user plane function (UPF) 120, network open function (NEF) 122 and / or other NFs. Some examples shown may apply to 3GPP 5G standards. However, some examples may also apply to 6G, 5G--Advanced, 4G, 3G and other 3GPP standards.

[0155] In e.g. Figure 1 In the wireless communication system 100 shown in , radio access is provided for mobile communication devices / terminals or user equipment, and / or user equipment (UE), and / or machine type communication devices through at least one base station or similar wireless transmission and / or reception node or point. Appropriate signal receiving and transmission devices can be provided for the terminal to communicate, which can, for example, enable (or otherwise facilitate) access to the communication network or communication directly with other devices. The communication device can access the carrier provided by the base station or access point and send and / or receive communications on the carrier.

[0156] Figure 2 An example of a control device 200 is shown. The control device 200 may be used to control the functions of one or more network entities / network functions, such as Figure 1 Entity of 5G--RAN 106 or 5GC 104 shown. The control device 200 includes at least one random access memory (RAM) 211a, at least one read-only memory (ROM) 211b, at least one processor 212, 213 and an input / output interface 214. At least one processor 212, 213 is coupled to RAM 211a and ROM 211b. At least one processor 212, 213 can be configured to execute appropriate software code 215. The software code 215 can, for example, allow one or more steps to be executed to perform one or more aspects or examples. The software code 215 can be stored in ROM 211b. The control device 200 can be interconnected with another control device 200 that controls another entity / function of 5G--RAN 106 or 5GC 104. In some examples, each function of 5G--RAN 106 or 5GC 104 includes a control device 200. In an alternative example, two or more functions of 5G--RAN 106 or 5GC 104 may share the control device 200. The control device 200 may include one or more circuits or circuit systems (circuitry) (not shown), which may be configured to perform one or more aspects or examples.

[0157] Figure 3 An example of a communication device 300 is shown, for example Figure 1 . The communication device 300 can be provided by any device capable of sending and receiving radio signals. In some examples, the communication device is a user equipment, a mobile station (MS) or a mobile device (e.g., a mobile phone or a so-called "smart phone"), a computer equipped with a wireless interface card or other wireless interface facilities (e.g., a USB dongle), a personal data assistant (PDA) or tablet computer equipped with wireless communication capabilities, a machine type communication (MTC) device, a cellular Internet of Things (cIoT) device, or any combination of these devices or similar devices. The communication device 300 can provide, for example, communication of data for carrying communication. The communication can be one or more of voice, electronic mail (email), text message, multimedia, data, machine data, etc.

[0158] The communication device 300 may receive signals via the air or radio interface 307 by appropriate means for receiving and may transmit signals by appropriate means for transmitting radio signals. Figure 3 In the mobile device, the transceiver arrangement is schematically indicated by block 306. The transceiver arrangement 306 may be provided, for example, by a radio part and an associated antenna arrangement. The antenna arrangement may be arranged internally and / or externally to the mobile device.

[0159] The communication device 300 may be equipped with at least one processor 301, at least one ROM 302a, at least one RAM 302b, and other possible components 303 for software and hardware assistance to perform the tasks it is designed to perform, including controlling access to and communication with access systems and other communication devices. At least one processor 301 is coupled to RAM 302b and ROM 302a. At least one processor 301 may be configured to execute appropriate software code 308. Software code 308 may, for example, allow execution of one or more aspects. Software code 308 may be stored in ROM 302a. The communication device 300 may include one or more circuits or circuit systems (not shown) that may be configured to perform one or more aspects or examples.

[0160] The processor, memory and other related control devices may be provided on an appropriate circuit board and / or in a chipset. This feature is indicated by reference numeral 304. In some examples, the device may optionally be equipped with a user interface, such as a keyboard 305, a touch screen or touchpad, a combination thereof, etc. In some examples, one or more of a display, a speaker and a microphone may be optionally provided depending on the type of device.

[0161] One or more of the following examples are related to device-to-device communications, such as New Radio (NR) sidelink (SL) communications. Sidelink is a feature of 5G systems that supports (or otherwise facilitates) direct communication between two devices without the need for a base station to be involved in the transmission and reception of data traffic. For sidelink-based communications, there may be single-hop (SH) or multi-hop (MH) UE-to-network (U2N) relay communications.

[0162] Single-hop (SH) U2N relay based on NR SL uses a single UE-to-network (U2N) relay UE between the remote UE and the serving network. MH U2N relay can be viewed as an extension of SH U2N relay, where the SHSL between the remote UE and the U2N relay UE can be extended to MH SL using SH or MH UE-to-UE (U2U) relay between the remote UE and the U2N relay UE. That is, the MH SL between the remote UE and the U2N relay UE is based on using SH U2U relay via a single U2U relay UE or using MH U2U relay via more than one U2U relay UE. U2N relay and U2U relay can be based on layer 2 (L2) or L3 relay solutions. In MH U2N relay, U2N relay and U2U relay may not necessarily be based on the same L2 or L3 relay solution. For example, the remote UE may connect to the serving gNB using an L2U2N relay UE via one or more L3U2U relay UEs between the remote UE and the L2U2N relay UE. In this case, the U2N relay connection between the remote UE and the serving gNB (via the L2U2N relay UE) is based on the L2U2N relay solution, and the extended SL connection between the remote UE and the L2U2N relay UE (via one or more L3U2N relay UEs) is based on the L3U2U relay solution.

[0163] Figure 4 A schematic diagram of a relay chain for multi-hop sidechain communication is shown.

[0164] A remote UE 401 is provided that is not directly connected to the network or base station. In other words, the remote UE 401 is beyond the coverage of the cell of the base station. A first U2U relay UE1 403, a second U2U relay UE2 405, and a third U2U relay UE3 407 are provided. A U2N relay UE 409 is also provided, which is connected to the gNB 411 (and within the coverage of the gNB 411). There is an extended end-to-end (E2E) side chain connection using multiple hops of the first, second and third U2U relay UEs 403, 405, 407 between the remote UE 401 and the U2N relay UE 409. Since there are multiple U2U relay UEs in the relay chain, this is called multi-hop.

[0165] In this way, Figure 4An SL-based L2MH U2N relay connection from a remote UE 401 to a serving gNB 411 via an L2U2N relay UE 409 is shown, wherein the SL-based connection between the remote UE 401 and the L2U2N relay UE 409 is provided via three U2U relay UEs 403, 405, 407.

[0166] In MH U2N relay, the U2N relay UE 409 is in good (e.g., direct) Uu coverage of the serving gNB / network 411 (e.g., DL RSRP at the U2N relay UE 409 is above a threshold). This is called the In-Coverage (IC) state. The remaining UEs (including the remote UE 401 and the U2U relay UEs 403, 405, 407) may be outside the direct Uu coverage of the serving network 409. This is called the Out-of-Coverage (OoC) state.

[0167] For L2MH U2N relay, after establishing the U2N relay connection to the gNB 411 for the remote UE 401, at least the remote UE 401 and the serving U2N relay UE 409 are in the RRC_CONNECTED state of the serving gNB 411. The remaining UEs (including at least one U2U relay UE 403, 405, 407) may be in any state of their serving network (e.g., RRC_IDLE / INACTIVE or RRC_CONNECTED towards the same or different serving gNB of the same or different serving network compared to the remote UE 401 and the U2N relay UE 409) or remain in the OoC state and the DETACHED state.

[0168] For L3MH U2N relay, the U2N relay UE 409 will be in the RRC_CONNECTED state serving the gNB 411. Other UEs (including the remote UE 401) may not be in the RRC_CONNECTED state.

[0169] Figure 5 5a to 5d are schematic diagrams showing different scenarios of remote user equipment.

[0170] exist Figure 5 In a, a remote UE 501, a U2U relay UE1 503, a U2U relay UE2 505, and a U2N relay UE 507 are provided. The U2N relay UE 507 is within the coverage of the gNB 509. Figure 5In a, there is no connection established between UEs 501, 503, 505, 507 (including the remote UE 501 of interest) or between UEs 503, 505, 507 and the network / gNB 509. In this case, the remote UE 501 may need to perform general or blind MH U2N relay discovery and selection to find and connect to a suitable U2N relay UE through one or more U2U relay UEs. The suitability here may include at least some upper layer criteria (e.g., the remote UE 501 and the serving U2N relay UE 507 are from authorized PLMNs). For example, the blind MH U2N relay discovery and selection can be initiated by the remote UE 501 broadcasting a blind MH U2N relay discovery (RD) request to find a suitable U2N relay UE 507 that can serve the remote UE 501 to connect to, for example, a target PLMN. If certain conditions are met, a U2U relay UE (e.g., U2U relay UE1 503) may further forward a blind MH U2NRD request (from a remote UE or another U2U relay UE) of a remote UE 501 by broadcasting after receiving it. For example, the reference signal received power (RSRP) on the received blind MH U2N relay discovery (RD) request is higher than a threshold, and the maximum number of hops or delay budget for forwarding based on the received blind MH U2N relay discovery (RD) request is still allowed. If the blind MH U2N RD request reaches a U2N relay UE 507, the U2N relay UE 507 may select one or more U2U relay UEs 505 (from which the blind MH U2N RD request is received and the RSRP is higher than the threshold) to send a MH U2N RD response to them. This triggers a similar U2U relay selection to forward the MH U2N RD response from the U2U relay UE2 505 to the U2U relay UE1 503 and then forwarded back to the downstream remote UE 501. The remote UE 501 may then select a U2N relay UE to first establish an end-to-end (E2E) MH U2U relay connection with the selected U2N relay UE 507. The remote UE 501 may then communicate with the selected U2N relay UE 507 to establish an MH U2N relay connection with the serving network 509 through the selected U2N relay UE 507. However, this process is associated with some issues. For example, blind multi-hop (MH) U2N relay discovery and selection includes two stages, including: (i) MH U2N relay discovery; and (ii) MH U2N relay selection and E2E sidelink (SL) MH relay connection establishment between the remote UE and the selected U2N relay UE via multiple selected U2U relay UEs. These may take considerable time, ie high latency. Furthermore, broadcasting blind MH U2N Relay Discovery (RD) requests may result in unnecessary forwarding of requests in all possible directions further away from the coverage of the target PLMN.This is called the message flooding problem.

[0171] Figure 5 b shows an example where the remote UE 501 is located near the U2U relay UE1 503 , which provides services for the E2E SL connection 511 between the remote UE1 513 and the U2N relay UE 507 .

[0172] Figure 5 c shows an example where the remote UE 501 is identical to (ie, the same UE as) the U2U relay UE1 503 , which provides services for the E2E SL connection 511 between the remote UE1 513 and the U2N relay UE 507 .

[0173] Figure 5 d shows that in addition to Figure 5 c is an example in which the U2U relay UE2 505 is providing service for another E2E SL connection 515 between the remote UE2 517 and the U2N relay UE2 519 .

[0174] However, for Figure 5 The scenarios shown in b to 5d can also be used with Figure 5 A similar relay discovery and selection process is used in a. However, as mentioned above, this process can have high latency and is prone to message flooding problems.

[0175] In some systems, when a remote UE needs to find and connect to a U2N relay UE to possibly access the network, the remote UE may perform U2N relay discovery and selection. In these systems, after discovering and selecting a U2N relay UE, the remote UE may perform a SL connection establishment with the selected U2N relay UE. The SL connection establishment is initiated by the remote UE sending a direct communication request (DCR) to the selected U2N relay UE using unicast. U2U relay discovery and selection may be integrated in the SL connection establishment process, or based on the use of a discovery process.

[0176] In some systems, for U2U relay discovery and selection, it is assumed that the remote UE has prior knowledge of information about the target UE (e.g., a U2N relay UE), and the remote UE needs to find a U2U relay UE to connect to the target UE. The remote UE may not always know this, because the remote UE may need to discover relay UE candidates for both U2U relay and U2N relay (e.g., in Figure 55a and 5b). That is, the remote UE may not know in advance which U2N relay UE may be selected. In this regard, extending these systems to MH U2N relay, i.e., the remote UE initiates a DCR integrated with U2U and U2N relay discovery and selection, is not straightforward. Furthermore, in these systems, the first message from the remote UE (e.g., a DCR or a discovery request (DS)) is broadcast and is therefore "flooded" by the remote UE and subsequent U2U relay UEs.

[0177] The following one or more examples are intended to address one or more of the problems set forth above, as well as other issues that would be apparent to one of ordinary skill in the art in light of the present disclosure.

[0178] In some examples, an apparatus is provided that is configured to determine a communication request associated with relay discovery and selection for a user equipment to network (U2N) relay connection establishment for a first user equipment (UE). The apparatus is also configured to provide the communication request to the U2N relay UE based on the communication request, via at least one first user equipment to user equipment (U2U) relay UE, using an established relay chain between the U2N relay UE and a second UE via at least one first U2U relay UE.

[0179] In some examples, if an existing MH U2N relay connection (such as Figure 5 b to 5d), the MH U2N relay discovery and selection of the remote UE will be faster and more efficient.

[0180] One or more of the following examples may address how to enable and facilitate utilization of an existing multi-hop U2N relay connection for a remote UE. In addition, what to do if an attempt to utilize such an existing multi-hop U2N relay connection fails.

[0181] Some of the following examples illustrate integrated MH U2N relay discovery and selection. During MH U2N relay discovery and selection, the use of broadcasts is minimized (e.g., reduced as much as possible) to speed up the establishment of an E2ESL connection between a remote UE and a selected U2N relay UE. This can reduce message flooding overhead (e.g., caused by broadcasts). Some of the examples illustrate that the remote UE and / or the involved U2U relay UEs use relay selection at any suitable hop or stage in the MH U2N relay discovery and selection for the remote UE. Since relay selection can be performed at any hop or stage in the relay chain, relay selection can be described as "proactive" relay selection. Proactive relay selection is based on using an existing MH U2N relay connection (also called a relay chain) with the remote UE and / or the involved U2U relay UE, and therefore uses SL unicast. For example, in Figure 5In b, the remote UE# is located near the U2U relay UE1 that currently serves the relay chain for the remote UE1. In this case, after determining that it is a relay UE candidate serving the remote UE#, the U2U relay UE1 can be allowed to perform (active) relay selection for the remote UE# by requesting the U2N relay UE1 for an MH U2U relay connection using its existing relay chain.

[0182] exist Figure 5 c, the remote UE# that is the same as the U2U relay UE1 serving the existing relay chain for the remote UE1 can be configured to perform relay selection for itself. This can also be applied to Figure 5 d. In addition, when Figure 5 When the relay selection of U2N relay UE1 initiated by the remote UE# in d fails and the failure is caused by U2N relay UE1 (for example, if it is unable or unwilling to act as the U2N relay UE for the remote UE#, or if it has reached its capacity limit), U2U relay UE2 can be allowed to use the second relay chain it is serving / belonging to to perform subsequent active relay (re)selection of U2N relay UE2 for the remote UE#.

[0183] In some examples, Figure 5 In scenario d, the U2U relay UE2 can overwrite the relay selection initiated by the remote UE# (for example, rewrite the information in the request), or use the second relay chain to perform parallel active relay selection for the remote UE# after receiving, for example, a DCR from the remote UE# (requesting to use the first relay chain to establish an E2E connection with the U2U relay UE1).

[0184] The remote UE or U2U relay UE may perform relay selection (or "active" relay selection) for an MH U2N relay request from the remote UE. For example, relay selection may include that the U2U relay UE may retry to perform relay selection when a previous relay selection failed for the same or ongoing MH U2N relay request of the remote UE. Thus, this avoids the need for the remote UE to initiate a new MH U2N relay request.

[0185] In some examples, a DCR process for optimizing (e.g., integrated, fast, and / or efficient) MH U2N relay discovery and selection is provided. The DCR process / DCR message may be described as an "open" DCR. An "open" DCR allows a remote UE or U2U relay UE to discover (or serve) a remote UE when acting as a U2U relay UE by utilizing (e.g., Figure 5c and 5d) or an established relay chain being served by a U2U relay UE to perform MH U2N relay discovery and selection. An "open" DCR also allows a U2U relay UE to add (or modify) relay selection information (e.g., add or modify information associated with a relay chain established in the DCR). In an "open" DCR, the remote UE may not provide information of a specific target UE (e.g., a selected U2N relay UE) from the beginning of relay connection establishment. During U2N relay UE discovery and selection of a MH U2N relay requested by the remote UE, this information may remain "open" to be determined by the U2U relay UE performing relay selection and subsequently included in the DCR. In some examples, when the target UE's information is initially included in an "open" DCR, the U2U relay UE performing relay selection of the remote UE's DCR may be allowed to rewrite the information to enhance the robustness of the DCR and relay selection. A request (e.g., an open DCR) may indicate that the U2U relay UE is allowed to perform relay selection for the connection. In other examples, the type (or format) of the message (eg, DCR) may indicate (eg, implicitly) that the U2U relay UE is allowed to perform relay selection for the connection.

[0186] In some examples, the DCR is provided by the remote UE, wherein the DCR is associated with the relay connection establishment. It should be understood that this is given as an example only. In other examples, at least one of the following may be used: a communication request, a communication request message, a request or a request message. In further examples, any suitable message or request message may be used.

[0187] In some examples, even if the remote UE does not have a previously selected target U2N relay UE, the serving network may configure the remote UE to determine and initiate a DCR in the uplink direction for MH U2N relay discovery and selection. This "open" DCR initiated by the remote UE may include information associated with relay selection utilizing a known U2N relay UE and an associated relay chain. The relay selection information may include, for example, an ID of the target U2N relay UE and / or an ID of an associated remote UE of an associated relay chain. When the (L2) IDs of the target U2N relay UE and the associated remote UE are included, a single relay chain to be used is selected. When one of the (L2) IDs of the target U2N relay UE and the associated remote UE is included, any path associated with the target U2N relay UE or the remote UE may be selected and used. It is assumed that the DCR may include further information, such as an MH U2N relay activation indication, the remote UE's associated UE ID and authorized PLMN ID, the maximum allowed number of hops, timing information (e.g., the expiration time of the DCR), etc.

[0188] When the DCR does include relay selection information (e.g., the remote UE is already a member of an existing MH U2N chain): the remote UE sends the DCR to the neighboring U2U relay UEs in the associated relay chain using SL unicast (e.g., see Figure 5 c and 5d). When the DCR does not include relay selection information: the remote UE uses SL broadcast to send an "open" DCR, allowing the upstream U2U relay UE to perform relay selection for the remote UE's DCR (see, for example Figure 5 a and 5b). The DCR without relay selection information allows a U2U relay UE participating in MH U2N relay discovery and selection for a remote UE to add or change the relay selection information in a received DCR before forwarding the DCR further. This may be under the control of the remote UE, for example, by providing control information or setting constraints or restrictions in the DCR initiated by the remote UE. In order to distinguish active relay selection initiated by the remote UE from active relay selection initiated by the U2U relay UE, a first indication (e.g., a 1-bit flag) may be included with the relay selection information. For example, if the relay selection information is initiated by the remote UE, the first indication is set to 1 (true), and vice versa.

[0189] In response to the DCR, the U2N relay UE that has received the DCR (also referred to as the receiving U2N relay UE) may provide a direct communication acceptance (DCA), a direct communication rejection (DCRj), or a discovery response (DR). The remote UE may receive multiple DCAs for the DCR initiated by it from different neighboring U2U relay UEs (SL--RSRP or RD--RSRP is above a configured threshold). This means that multiple possible relay chains to different U2N relay UEs may be established for the remote UE. In this case, the remote UE may select one of them and release the rest. The subsequent DCR that the remote UE retries after receiving DCRj may include a list of non-preferred or excluded U2N relay UEs and / or U2U relay UEs that rejected the remote UE's previous open DCR. The L2ID of the source relay UE of DCRj may be included in DCRj. The L2ID of the U2N relay UE or U2U relay UE that rejected the remote UE's DCR may be included in DCRj to be sent back to the remote UE in the downlink direction.

[0190] In some examples, the serving network can configure the U2N relay UE to determine whether and how to respond to the DCR in the downlink direction after receiving one or more instances of the remote UE's DCR from one or more U2U relay UEs (whose SL--RSRP or RD--RSRP is above a configured threshold), as shown below.

[0191] The U2N relay UE may determine whether to respond using DCA, DCRj, or DR. This may be determined by the implementation of the U2N relay UE. In some examples, the U2N relay UE determines to use DCA or DCRj to respond to the DCR of the remote UE after receiving a DCR including relay selection information (in this case, an open DCR is sent / received using unicast). The U2N relay UE selects one of the one or more U2U relay UEs, prioritizing the U2U relay UE that sends the DCR with relay selection information. This determination may be based on the first indication (as described above). The U2N relay UE then sends the DCA or DCRj to the selected U2U relay UE (to be forwarded to the remote UE). DCRj may include a second indication (e.g., a 1-bit flag) to indicate whether the DCRj is initiated from the U2N relay UE or the U2U relay UE. If the DCRj is initiated by the U2N relay UE, the second indication is set to, for example, 1 (true).

[0192] In some examples, the U2N relay UE determines to respond with a DR after receiving a DCR without relay selection information (in this example, the DCR may be sent / received using broadcast). The U2N relay UE may select up to a configured maximum number of U2U relay UEs from one or more U2U relay UEs. The U2N relay UE then sends the DR to the selected U2U relay UEs individually (to be forwarded to the remote UE).

[0193] In some examples, the U2U relay UE can be configured by the serving network and / or controlled by the remote UE to determine to perform one or more of the following operations after receiving one or more instances of the remote UE's DCR (from the remote UE and / or other U2U relay UEs) where the SL--RSRP or RD--RSRP is above a configured threshold.

[0194] In some examples, when one or more received instances of a DCR include relay selection information associated with at least one U2N relay UE, and when the U2U relay UE is able to accept the DCR of the remote UE: the U2U relay UE selects one of the received DCR instances having relay selection information for each corresponding U2N relay UE. The U2U relay UE may prioritize the relay selection information initiated by the remote UE (as indicated by a first indication set to true). In some examples, the U2U relay UE may be configured to select one of the received DCR instances having relay selection information across all corresponding U2N relay UEs to further reduce overhead. The selection may be based on a SL condition (RSRP rank between the U2U relay UE and its neighbors from which the DCR instances were received), or randomly selected, provided that all selectable options should satisfy a predefined SL condition (RSRP above a threshold). The U2U relay UE then forwards the selected DCR instance to at least one corresponding U2N relay UE using SL unicast, utilizing the associated relay chain indicated in the relay selection information of the selected instance of the open DCR.

[0195] In some examples, when the U2U relay UE cannot accept the DCR from the remote UE, the U2U relay UE may determine whether to send DCRj. This may be left to the implementation of the U2U relay UE, at least in response to a DCR with relay selection information initiated by other U2U relay UEs rather than the remote UE. This means that if the U2U relay UE cannot accept the DCR with relay selection information initiated by the remote UE, it may be configured to send DCRj. In some examples, a DCRj initiated from an intermediate U2U relay UE in the relay chain may help trigger a retry of a DCR initiated from the remote UE for MH U2N relay discovery and selection. In some examples, when the U2U relay UE determines to send DCRj: the U2U relay UE may send DCRj to each sender of at least one receiving instance of the DCR with relay selection information or one or more selected senders. In this example, the second indication is set to 0 (false). In addition, the ID of the U2U relay UE may be included in the DCRj to identify the source U2U relay UE of the DCRj. The remote UE can use this to avoid selecting a relay UE of a failed relay chain.

[0196] In some examples, when the DCR does not include relay selection information and the U2U relay UE is able to accept the open DCR of the remote UE, the U2U relay UE can determine whether the U2U relay UE is currently serving the relay chain of another remote UE. In some examples, when the U2U relay UE is serving at least one relay chain of the same serving network to the remote UE (e.g., an ongoing established / existing relay chain for another remote UE), then at least one relay chain is available for the remote UE (e.g., Figure 5 b). The U2U relay UE determines relay selection information associated with one of the at least one relay chains and adds the relay selection information to the DCR of the remote UE. In this example, the first indication can be set to 0 (false) (because it is the U2U relay UE that adds the relay selection information associated with the relay chain to the DCR). In some examples, the relay selection information associated with the relay chain can be the ID of the U2N relay UE serving the relay chain and / or the ID of other remote UEs using the relay chain.

[0197] After adding the relay selection information associated with the relay chain to the DCR, the U2U relay UE forwards the remote UE's DCR to the selected U2N relay UE using SL unicast using the relay chain indicated in the relay selection information.

[0198] In some examples, when the U2U relay UE determines that the U2U relay UE receiving the DCR (without relay selection information) from the remote UE does not provide services for any relay chain of other remote UEs, the U2U relay UE may forward the DCR of the remote UE using SL broadcast. Forwarding by broadcast may depend on other settings / information included in the DCR, such as maximum number of hops, timing information.

[0199] In some examples, when the DCR received at the U2U relay UE does not include relay selection information but the U2U relay UE cannot accept the open DCR of the remote UE, the U2U relay UE may ignore the DCR of the remote UE.

[0200] In some examples, the U2U relay UE can be configured by the serving network and / or controlled by the remote UE to determine whether and how to further respond to the remote UE's DCR upon receiving a response associated with the remote UE's DCR in the downlink direction from a U2N relay UE or a neighboring U2U relay UE (where the SL--RSRP or RD--RSRP is above a configured threshold).

[0201] In some examples, when the received response associated with the remote UE's DCR is a DCA, the U2U relay UE may send (or forward) a DCA to the remote UE. The sending may be: directly to the remote UE if the U2U relay UE receives the DCR from the remote UE, or through a selected neighboring U2U relay UE from which the remote UE's DCR was received. The selection of the selected neighboring U2U relay UE gives priority to U2U relay UEs that send DCRs with relay selection information. When the relay selection information is initiated by the remote UE (as indicated by the first indication), this may be applied using the same relay chain used to send the DCR.

[0202] In some examples, when the received response associated with the remote UE's DCR is DCRj and DCRj is initiated by a U2N relay UE (based on the second indication and the ID of the U2N relay UE), the receiving U2U relay UE can determine whether it is serving another relay chain toward a different U2N relay UE for another remote UE. In some examples, when the U2U relay UE is serving other relay chains for different U2N relay UEs available to the remote UE (compared to the relay chain associated with the received DCRj) (e.g., see Figure 5 d), the U2U relay UE determines the relay selection information associated with the other relay chains for the DCR of the remote UE for retrying. The U2U relay UE then includes the relay selection information associated with the other relay chains in the DCR of the remote UE. This may include replacing / overwriting the failed relay selection information. The U2U relay UE then forwards the DCR to the (re)selected U2N relay UE using SL unicast using the other relay chains indicated in the relay selection information.

[0203] If a timer or counter (associated with the DCR) allows, a determination to retry establishing a relay connection for the remote UE may occur, which means that the U2U relay UE may only perform a retry within the time limit set by the remote UE for MH relay discovery and selection for the remote UE. This is referred to as the timing information mentioned above. A maximum number of retries may also be configured for the DCR. For example, a maximum number of 2 retries may be allowed before the process ends. In other examples, more or less than 2 retries may be allowed / configured.

[0204] In some examples, the U2U relay UE sends / forwards the DCRj to the remote UE, directly to the remote UE if the DCR is received from the remote UE, or through a selected neighboring U2U relay UE from which the open DCR of the remote UE is received. The selection of the selected neighboring U2U relay UE gives priority to U2U relay UEs that send DCRs with relay selection information. Specifically, when the remote UE initiates the relay selection information (as indicated by the first indication), the same relay chain used to send the DCR is preferentially used.

[0205] In some examples, DCRj may include a third indication (e.g., a 1-bit flag) to indicate at least one retry (or retry) to perform relay (re)selection. Therefore, based on the third indication, the subsequent U2U relay UE or remote UE may skip the additional retry. Based on DCRj, the subsequent U2U relay UE or remote UE may know that regardless of the retry result, its selected U2N relay UE (in the relay selection information) is not available. After receiving DCRj, the subsequent U2U relay UE or remote UE may also initiate a retry (excluding the U2N relay UE that initiated DCRj) while monitoring the result of the retry initiated by the U2U relay UE.

[0206] In some examples, if the U2U relay UE does not find another relay chain for retry or the retry also fails, the U2U relay UE forwards the DCRj to the remote UE.

[0207] In some examples, when DCRj has been initiated by another U2U relay UE (e.g., based on the second indication and the ID of the source U2U relay UE of DCRj), the U2U relay UE may determine whether to further send DCRj to the remote UE. Additionally or alternatively, the U2U relay UE may determine whether to perform a retry of relay (re)selection. This may be left to the implementation of the U2U relay UE.

[0208] In some examples, when the response to the DCR associated with the remote UE is a DR, the U2N relay UE may send a DR to the remote UE. If the U2U relay UE receives a DCR from the remote UE, the DR may be sent directly to the remote UE or through a selected neighboring U2U relay UE of the maximum number from which the remote UE's DCR was received. The remote UE or the serving network may set / configure the maximum number of U2U relay UEs in the DCR.

[0209] These examples and related aspects are discussed below. Figures 6 to 8 Describe together in more detail.

[0210] Figure 6 An example signaling diagram for establishing a multi-hop relay connection is shown. Figure 6 and Figure 5 Related to the example scenario provided in b.

[0211] At S600, there is an ongoing / established relay chain for a first remote UE (referred to as "remote UE1") served by a first U2U relay UE (referred to as "U2U relay UE1"), a second U2U relay UE (referred to as "U2U relay UE2"), and a U2N relay UE (referred to as "L2U2N relay UE1"). L2U2N relay UE1 is connected to the network and has a serving gNB. The relay chain may also be referred to as an extended SL connection or MH SL between a remote UE and a U2N relay UE in an MH U2N relay connection for the remote UE, which is being served by one or more U2U relay UEs.

[0212] At S601, a remote UE (referred to as "remote UE#") is provided. The remote UE# is beyond the coverage of the network / gNB. The remote UE# initiates MH U2N relay discovery and selection in order to obtain network access.

[0213] At S602, the remote UE# provides a request message associated with MH U2N relay connection establishment. In this way, the request message can be associated with MH U2N relay discovery and selection. The request message can be a connection request or a DCR. The connection request (or DCR) can be integrated with MH U2N relay discovery and selection, the latter of which can also be referred to as an "open" DCR.

[0214] As described above, the open DCR enables (or otherwise facilitates) active MH U2N relay discovery and selection performed by the remote UE or by a U2U relay UE candidate that receives the open DCR of the remote UE using the established relay chain. The remote UE or U2U relay UE candidate is aware of the established relay chain, for example because the remote UE or U2U relay UE candidate is serving the relay chain as a U2U relay UE, or due to an earlier discovery process, etc. Based on performing active MH U2N relay discovery and selection, relay selection information including information associated with the established relay chain may be included in the open DCR from the beginning by the remote UE (that initiates the open DCR), or by the U2U relay UE candidate that receives and forwards the open DCR of the remote UE for MH U2N relay connection establishment.

[0215] In some examples, the request message may include information associated with the established relay chain. For example, the information may include an identification (ID) of the U2N relay UE and / or an ID of a remote UE associated with the relay chain. The information may also include an ID of a U2U relay UE associated with the relay chain.

[0216] exist Figure 6 In the example (with Figure 5 b), the remote UE# has not previously established a SL connection with any U2U relay UE or U2N relay UE. Therefore, the request message does not include information associated with an established relay chain, also called relay selection information. In other words, the remote UE# avoids including information associated with an established relay chain. This may be because the remote UE# is not aware of any established relay chain that the remote UE# may have established with its MH U2N relay connection. It should be noted that the remote UE# may act as a U2U relay UE in a (separate) established relay chain for other remote UEs, such as Figure 5 c and 5d. The request message can be broadcast by the remote UE#. Assume that the request message reaches the remote UE1 and the U2U relay UE1, which are located near the remote UE#, such as Figure 5 As shown in b.

[0217] In some examples, the request message may include information indicating that the request message is an "open" DCR with integrated MH U2N relay discovery and selection. The indicative information may be referred to as an MH U2N relay enabled indication. The indicative information may include at least one of the following: a relevant UE ID of the remote UE (the remote UE may also act as a U2U relay UE for other remote UEs), an authorized PLMN ID of the remote UE, a maximum allowed number of hops of the MH U2N relay requested by the remote UE, timing information (e.g., an expiration time of the DCR), or a maximum allowed number of retries for active relay (re)selection of a U2U relay UE candidate of the remote UE.

[0218] At S603, the U2U relay UE1 receives a request message from the remote UE#. The U2U relay UE1 may determine to provide a service for the request. Based on the request message, the U2U relay UE1 determines whether to perform relay selection.

[0219] The U2U relay UE1 determines whether the request message includes information associated with the established relay chain. In this way, the U2U determines whether to perform relay selection on the request message (eg, open DCR) of the remote UE#.

[0220] When the request message includes information associated with the established relay chain, the U2U relay UE1 uses the information to forward the request message using the established relay chain. For example, the request message includes the ID of the U2N relay UE1.

[0221] When the request message does not include information associated with established relay chains, the U2U relay UE1 determines / discovers one or more established relay chains available for the request of the remote UE.

[0222] exist Figure 6In this example, U2U relay UE1 has an established relay chain with U2N relay UE1 to serve remote UE1. U2U relay UE1 retrieves (or determines) information of the established relay chain, wherein the information includes the ID of U2N relay UE1 and / or the ID of remote UE1. Information about the established relay chain is available to U2U relay UE1. In this way, the information is associated with relay selection information. U2U relay UE1 inserts the information into the request message. In this way, U2U relay UE1 can insert the information into the open DCR. In other words, U2U relay UE1 updates the request message to include the information. After the insertion, the request includes information associated with relay selection, indicating that the established relay chain includes at least the identity of the U2N relay UE.

[0223] At S604a, the U2U relay UE1 provides a request message to the U2N relay UE1 through the U2U relay UE2. The request message is provided by unicast using the established relay chain.

[0224] In order to distinguish the relay selection initiated by the remote UE from the relay selection initiated by the U2U relay UE, a first indication and the information may be provided in the request message. The indication may be included by the U2U relay UE1. The indication may be, for example, a flag. For example, when the relay selection information is provided by the remote UE# (e.g., the relay selection is initiated by the remote UE#), the first indication is set to 1 (e.g., true), or when the relay selection information is provided by the U2U relay UE1 (e.g., the relay selection is initiated by the U2U relay UE1), the first indication is set to 0 (e.g., false). In other examples, the two options of the first indication are switched.

[0225] In this example, the request message includes a first indication which is set to “false”. This indicates that the relay selection information is provided by the U2U relay UE1.

[0226] At S605, the U2N relay UE1 receives the request message. The U2N relay UE1 determines whether to accept the request message. The U2N relay UE1 may determine whether to respond with a direct communication acceptance (DCA), a direct communication rejection (DCRj), or a discovery response (DR). This may be determined based on the implementation of the U2N relay UE1.

[0227] In this example, U2N relay UE1 determines to accept the request from remote UE#.

[0228] At S606a to S606c, a message (eg, DCA) accepting the request is provided to the remote UE# via the U2U relay UE2 and the U2U relay UE1.

[0229] At S607 , an E2E SL MH relay connection is established for the remote UE# and the U2N relay UE1 .

[0230] Figure 7 An example signaling diagram for establishing a multi-hop relay connection is shown. Figure 7 and Figure 5 c.

[0231] Figure 7 Shown with Figure 6 The example is similar to the example in , except that the remote UE# (which requests the relay connection) is the same as the U2U relay UE (which provides services for the established relay chain for another remote UE). In other words, the remote UE# has been configured as part of the relay chain of another remote UE (e.g., remote UE1). The remote UE# acts as the U2U relay UE1 of the relay chain between the remote UE1 and the U2N relay UE1.

[0232] At S700, there is an ongoing / established relay chain for a first remote UE (referred to as "remote UE1") served by a first U2U relay UE (referred to as "U2U relay UE1"), a second U2U relay UE (referred to as "U2U relay UE2"), and a U2N relay UE (referred to as "L2U2N relay UE1"). L2U2N relay UE1' is connected to the network and has a serving gNB. The relay chain may be referred to as an extended SL connection. The relay chain may be referred to as an MH SL between the remote UE and the U2N relay UE in the MH U2N relay connection.

[0233] At S701, the remote UE# initiates MH U2N relay discovery and selection in order to obtain network access. The remote UE# initiates a request message associated with MH U2N relay connection establishment. In this way, the request message can be associated with MH U2N relay discovery and selection. The request message can be a connection request. The request message can be a DCR integrated with MH U2N relay discovery and selection (also known as an open DCR).

[0234] In some examples, the request message includes information associated with the established relay chain. For example, the information may include an identification (ID) of the U2N relay UE and / or an ID of a remote UE associated with the relay chain. Since the remote UE# has acted as a U2U relay UE for the remote UE1, the remote UE# is aware of the established relay chain.

[0235] The remote UE # inserts the information associated with the relay chain into the request message. After the insertion, the request includes information associated with the relay selection, indicating the established relay chain, including at least the identity of the U2N relay UE.

[0236] At S702a, the remote UE# / U2U relay UE1 uses the established relay chain to provide a request message to the U2N relay UE1 through the U2U relay UE2. The request message is provided using unicast. The U2N relay UE1 is identified based on the information.

[0237] In order to distinguish between the relay selection initiated by the remote UE and the relay selection initiated by the U2U relay UE, a first indication and the information may be provided in the request message. The indication may be, for example, a flag. For example, when the relay selection information is provided by the remote UE# (e.g., the relay selection is initiated by the remote UE#), the first indication is set to 1 (e.g., true), or when the relay selection information is provided by the U2U relay UE1 (e.g., the relay selection is initiated by the U2U relay UE1), the first indication is set to 0 (e.g., false). In other examples, the two options of the first indication are switched.

[0238] In this example, the request message includes a first indication set to "true". This indicates that the relay selection information is provided by the remote UE# (same as the U2U relay UE1).

[0239] At S703, the U2N relay UE1 receives the request message. The U2N relay UE1 determines whether to accept the request message. The U2N relay UE1 may determine whether to respond with a direct communication acceptance (DCA), a direct communication rejection (DCRj), or a discovery response (DR). This may be determined based on the implementation of the U2N relay UE1.

[0240] In this example, U2N relay UE1 determines to accept the request from remote UE#.

[0241] At S704a to S704b, the U2U relay UE2 provides a message (eg, DCA) accepting the request to the remote UE#.

[0242] At S705 , an E2E SL MH relay connection is established between the remote UE# and the U2N relay UE1 .

[0243] Figure 8 Another example signaling diagram for establishing a multi-hop relay connection is shown. Figure 8 and Figure 5 d.

[0244] Figure 8 and Figure 7Similarly, because the remote UE# (which requests the relay connection) is the same as the U2U relay UE (which provides services for the established relay chain for another remote UE). In other words, the remote UE# has been configured as part of the relay chain for another remote UE (e.g., remote UE1). The remote UE# acts as the U2U relay UE1 of the relay chain between the remote UE1 and the U2N relay UE1.

[0245] At S800a, there is an ongoing / established relay chain for a first remote UE (referred to as "remote UE1") served by a first U2U relay UE (referred to as "U2U relay UE1"), a second U2U relay UE (referred to as "U2U relay UE2"), and a U2N relay UE (referred to as "L2U2N relay UE1"). L2U2N relay UE1' is connected to the network and has a serving gNB. The relay chain may be referred to as an extended SL connection. The relay chain may also be referred to as an MHSL between a remote UE and a U2N relay UE in an MH U2N relay connection.

[0246] At S800b , there is another established relay chain for remote UE2 served by U2U relay UE2 , U2U relay UE3 , and L2U2N relay UE2 .

[0247] In this way, in Figure 8 In the example of , there is an established relay chain for remote UE1, and another established relay chain for remote UE2.

[0248] At S801, the remote UE# initiates MH U2N relay discovery and selection to obtain network access. The remote UE# initiates a request message associated with MH U2N relay connection establishment. In this way, the request message may be associated with MH U2N relay discovery and selection. The request message may be a connection request. The request message may be a DCR integrated with MH U2N relay discovery and selection (also known as an open DCR).

[0249] In some examples, the request message includes information associated with the established relay chain. For example, the information may include an identification (ID) of the U2N relay UE and / or an ID of a remote UE associated with the relay chain. Since the remote UE# has acted as a U2U relay UE for the remote UE1, the remote UE# is aware of the established relay chain.

[0250] Remote UE # inserts information associated with the relay chain into the request message. In this example, it includes the ID of U2N relay UE1. After the insertion, the request includes information associated with relay selection, indicating the established relay chain, including at least the identity of the U2N relay UE.

[0251] At S802a, the remote UE# / U2U relay UE1 uses the established relay chain to provide a request message to the U2N relay UE1 through the U2U relay UE2. The request message is provided using unicast. The U2N relay UE1 is identified based on the information.

[0252] In order to distinguish the relay selection initiated by the remote UE from the relay selection initiated by the U2U relay UE, a first indication and the information may be provided in the request message. The indication may be, for example, a flag. For example, when the relay selection information is provided by the remote UE# (e.g., the relay selection is initiated by the remote UE#), the first indication is set to 1 (e.g., true), or when the relay selection information is provided by the U2U relay UE1 (e.g., the relay selection is initiated by the U2U relay UE1), the first indication is set to 0 (e.g., false). In other examples, the two options of the first indication are switched.

[0253] In this example, the request message includes a first indication set to "true". This indicates that the relay selection information is provided by the remote UE# (same as the U2U relay UE1).

[0254] At S803, the U2N relay UE1 receives the request message. The U2N relay UE1 determines whether to accept the request message. The U2N relay UE1 may determine whether to respond with a direct communication acceptance (DCA), a direct communication rejection (DCRj), or a discovery response (DR). This may be determined based on the implementation of the U2N relay UE1.

[0255] In this example, U2N relay UE1 determines to reject the request from remote UE#. The rejection message may be DCRj.

[0256] When the request is to be rejected, the rejection (e.g., DCRj) may include a second indication to indicate whether the DCRj is initiated from a U2N relay UE or a U2U relay UE. The second indication may be, for example, a 1-bit flag. For example, when the DCRj is initiated by a U2N relay UE, the second indication is set to 1 (true). When the DCRj is initiated by a U2U relay UE, the second indication is set to 0 (false). In other examples, the two options are switched.

[0257] At S804a , the U2N relay UE1 provides a rejection message to the U2U relay UE2 , in which the second indication is set to 1 (true).

[0258] At S804b, the U2U relay UE2 receives the rejection message and determines to resend the request for MH U2N relay establishment for the remote UE#. In other examples, the U2U relay UE2 receives the rejection message and determines to resend the open DCR with relay reselection for MH U2N relay establishment for the remote UE#. In other words, the U2U relay UE2 determines to retry establishing the MH U2N relay connection for the remote UE#.

[0259] The U2U relay UE2 is part of another established relay chain of the remote UE2.

[0260] At S804c, the U2U relay UE2 provides a rejection message to the remote UE# / U2U relay UE1. The rejection message includes a second indication.

[0261] The rejection message (e.g., DCRj) may also include a third indication to indicate that at least one retry of active relay (re)selection is performed for the open DCR of the remote UE. The third indication may be, for example, a 1-bit flag. The third indication is set to 1 (true) when a retry has been attempted. Based on the third indication, subsequent retries by the U2U relay UE or remote UE may be skipped. Based on the rejection message, the receiving U2U relay UE or remote UE# may know that its selected U2N relay UE1 is unavailable (regardless of the result of the retry).

[0262] At S804d, the U2U relay UE2 uses another established relay chain to provide a request message to the U2N relay UE2 through the U2U relay UE3 (S804e). The request message is sent by unicast. The request message includes information associated with another established relay chain. For example, the ID of the U2N relay UE2 and / or the ID of the remote UE2. In the request message, the first indication is set to 0 (false).

[0263] At S805a, the remote UE# receives the rejection message and determines the result of waiting for the retry. The remote UE# knows the retry according to the third indication set to true. In some examples, the subsequent U2U relay UE or remote UE may also initiate a retry after receiving the DCRj, excluding the U2N relay UE that initiated the DCRj, while monitoring the result of the retry initiated by the U2U relay UE. In another example, if the U2U relay UE2 does not find another relay chain for retry or the retry also fails, it only forwards the DCRj to the remote UE#.

[0264] At S805b, the U2N relay UE2 receives the request message. The U2N relay UE2 determines whether to accept the request message. The U2N relay UE2 may determine whether to respond using direct communication acceptance (DCA), direct communication rejection (DCRj), or discovery response (DR). This may be determined based on the implementation of the U2N relay UE2.

[0265] In this example, U2N relay UE2 determines to accept the request from remote UE#.

[0266] At S806a to S806c, a message (eg, DCA) accepting the request is provided to the remote UE# via the U2U relay UE3 and the U2U relay UE2.

[0267] At S807 , an E2E SL MH relay connection is established between the remote UE# and the U2N relay UE2.

[0268] It should be understood that in some examples, Figures 6 to 8 One or more of the signaling steps in any of may not be performed, or may be performed in a different order. In some examples, Figures 6 to 8 One or more signaling steps in any of can be combined. In some examples, Figures 6 to 8 One or more intermediate signaling steps are performed between the signaling shown in any of the above.

[0269] In some examples, the remote UE may control the relay selection of the U2U relay UE via a corresponding control information element included in the DCR for subsequent retries of the remote UE's DCR. The control information element may indicate whether to enable or disable relay selection of the U2U relay UE. The control information element may indicate whether to enable or disable retry or retry of relay (re)selection by the U2U relay UE with an open DCR for the remote UE. The control information element may also indicate whether to enable or disable parallel retry or retry of relay (re)selection by the U2U relay UE with an open DCR for the remote UE. The control information element may set the maximum number of hops of the MH U2N relay connection for the remote UE, which may be used for relay selection of the U2U relay UE. The control information element may set a counter limit for the number of retries of relay (re)selection for the same U2U relay UE.

[0270] In some examples, at least some control information elements may be configured by a serving network common to all relevant UEs using a system information block (SIB), dedicated signaling, or pre-configuration to support IC and OoC operations.

[0271] In some examples, the remote UE may indicate an end timer of the DCR procedure in the DCR message. The "end timer" may be a timer, a counter, etc. Based on the end timer, the U2U relay UE or the U2N relay UE may determine whether to participate in the request or release its participation in the DCR serving the remote UE. The end timer may be considered as part of the timing information included in the request message, i.e., the open DCR.

[0272] In some examples, a DCA initiated from a U2N relay UE in response to a remote UE's DCR may indicate an instance number of a DCR that the U2N relay UE has received. The instance number represents an alternative connection to the U2N relay UE, and thus the remote UE may use the instance number to select a U2N relay UE and an associated relay chain if multiple relay chains via different U2N relay UEs are established.

[0273] In some examples, different DCR messages sent by different remote UEs may be combined by the U2U relay UE into a single DCR to be forwarded to the next U2U relay UE or U2N relay UE. Combining may occur when the U2U relay UE receives different DCR messages for different remote UEs and determines that multiple DCRs in the received DCR are involved. The same applies to different DCA messages or different DCRj messages.

[0274] In some examples, at least a U2U relay UE member of an existing / established MH U2N relay connection or relay chain may, for example, advertise or announce the existence of the relay chain in a discovery announcement message, and optionally include information about the relay chain. The information about the relay chain may include at least one of the following: an ID of the U2N relay UE in the discovery announcement message, an ID of a remote UE, an ID of the U2U relay UE, an ID of a serving PLMD, an ID of a serving cell, a number of hops, etc. The U2U relay UE member may send this announcement message by broadcasting. Therefore, another remote UE that receives such an announcement from one or more U2U relay UEs may use the received announcement to discover an established relay chain that can be used to quickly and efficiently establish a MH U2N relay connection.

[0275] In some examples, a system information block (SIB), such as SIB1 of the serving cell of the U2N relay UE, may be provided with a response message sent by the U2N relay UE to the remote UE (in response to the DCR from the remote UE). The response may be DCA, DCRj or DR.

[0276] In some examples, the reason (or reasons) for rejecting the open DCR from the remote UE is included in the DCRj from the U2N relay UE. The reason / reason can be selected from a preconfigured list of predefined reasons associated with corresponding cause values. Examples of cause values ​​can be: bandwidth of the U2N or U2U relay UE, and Uu or SL congestion. This will help the nearest U2U relay UE receiving this DCRj to make a "mitigation" decision. For example, a load problem at the U2N relay may trigger a search for an alternative U2N relay served by the same gNB. In another example, Uu congestion (e.g., core network congestion) may trigger a search for an alternative U2N relay served by another gNB.

[0277] One or more of the examples discussed above provide a mechanism by which a remote UE can use an established or existing relay chain for MH U2N relays to find or establish a MH U2N relay connection. This has the following advantages: faster establishment of the MH U2N relay connection for the remote UE and reduced message flooding issues in MH U2N relay discovery and selection.

[0278] Fig. 9 An example method flow performed by an apparatus is shown. In some examples, the apparatus is used for a first UE. In some examples, the apparatus is included in the first UE. In an example, the apparatus is a first UE. In some examples, the apparatus is used for a U2U relay UE. In some examples, the apparatus is included in a U2U relay UE. In some examples, the apparatus is a U2U relay UE. In some examples, the apparatus is used for a U2U relay UE with a relay chain established. In some examples, the apparatus is used for the first UE and also for a U2U relay UE with a relay chain established.

[0279] In S901 , the method includes determining a communication request associated with relay discovery and selection for a user equipment to network (U2N) relay connection establishment for a first user equipment (UE).

[0280] In S903, the method includes providing a communication request to a U2N relay UE via at least one first user equipment to user equipment (U2U) relay UE based on a communication request, using a relay chain established between the U2N relay UE and the second UE via at least one first U2U relay UE.

[0281] Fig.10 An example method flow performed by an apparatus is shown. In some examples, the apparatus is used for a first UE. In some examples, the apparatus is included in the first UE. In some examples, the apparatus is the first UE.

[0282] In S1001, the method includes initiating a communication request associated with relay discovery and selection for establishing a user equipment to network (U2N) relay connection for a first user equipment (UE), wherein the communication request is a request for a connection between the first UE and the U2N relay UE via at least one first user equipment to user equipment (U2U) relay UE, wherein the communication request indicates that at least one first U2U relay UE is allowed to perform relay selection for the connection.

[0283] In S1003 , the method includes providing a communication request to at least one U2U relay UE.

[0284] Fig.11 An example method flow performed by an apparatus is shown. In some examples, the apparatus is used for a U2N relay UE. In some examples, the apparatus is included in a U2N relay UE. In some examples, the apparatus is a U2N relay UE.

[0285] In S1101, the method includes receiving a communication request associated with relay discovery and selection from a user equipment to user equipment (U2U) relay user equipment (UE), wherein the communication request is a request for a connection between a first UE and a user equipment to network (U2N) relay UE via at least one U2U relay UE, wherein the communication request indicates that at least one U2U relay UE is allowed to perform relay selection for connection.

[0286] In S1103 , the method includes providing, based on the communication request, a response to the communication request to the first UE via the U2U relay UE.

[0287] Fig.12 A schematic diagram of a non-volatile storage medium 1200a (e.g., a Blu-ray Disc (BD), a computer disk (CD), or a Digital Versatile Disc (DVD)) and 1200b (e.g., a flash memory, a solid-state memory, a Universal Serial Bus (USB) memory stick) storing instructions and / or parameters 1202 that, when executed by at least one processor, allow the at least one processor to perform Fig. 9 , Fig.10 or Fig.11 One or more steps of a method.

[0288] It should be noted that although various examples are described above, many changes and modifications may be made to the various examples without departing from the scope of the present disclosure.

[0289] Therefore, the examples may vary within the scope of the present disclosure. Generally, some examples may be implemented in hardware or dedicated circuits, software, logic, or any combination thereof. For example, some examples may be implemented in hardware, while other examples may be implemented in firmware or software, which may be executed by a controller, microprocessor, or other computing device, but these examples are not limited thereto. Although various examples may be illustrated and described with block diagrams, flow charts, or using other graphical representations, it is fully understood that the blocks, devices, systems, techniques, or methods described herein may be implemented with hardware, software, firmware, dedicated circuits or logic, general hardware or controllers or other computing devices, or combinations thereof.

[0290] Examples may be implemented by computer software stored in a memory and executable by at least one data processor of the entity involved, or by hardware, or a combination of software and hardware. Furthermore, in this regard, it should be noted that any process may represent program steps, or interconnected logic circuits, blocks and functions, or a combination of program steps and logic circuits, blocks and functions. The software may be stored on physical media such as memory chips or memory blocks implemented within a processor, magnetic media (e.g., hard disk or floppy disk), and optical media (e.g., DVD and its data variant CD).

[0291] The term "non-transitory" as used herein is a limitation on the medium itself (eg, tangible, rather than a signal), rather than on the persistence of data storage (eg, RAM vs. ROM).

[0292] As used herein, "at least one of: " and "at least one of " and similar expressions, where a list of two or more elements is connected by "and" or "or", mean at least any one of the elements, or at least any two or more of the elements, or at least all of the elements. As used herein, the term "and / or" includes any and all combinations of one or more of the listed items.

[0293] As used herein, unless explicitly stated, performing a step "in response to A" does not necessarily mean that the step is performed immediately after "A" occurs, as one or more intermediate steps may be included.

[0294] The memory may be of any type suitable for the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and removable memory. The data processor may be of any type suitable for the local technical environment and may include 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), a gate-level circuit, and a processor based on a multi-core processor architecture, as non-limiting examples.

[0295] As used herein, the term "component for..." or "component configured to perform..." (or similar) may be any component suitable for performing the feature. A "component" may be configured to perform one or more functions and / or method steps previously described. For example, a "component" may include one or more of the following: at least one processor, at least one memory, transceiver circuitry, antenna circuitry, etc. It should be understood that these are provided herein as examples.

[0296] Additionally or alternatively, some examples may be implemented using a circuit system. The circuit system may be configured to perform one or more functions and / or method steps described previously. The circuit system may be provided in a base station and / or a communication device.

[0297] As used herein, the term "circuitry" may refer to one or more or all of the following examples:

[0298] (a) pure hardware circuit implementation (e.g., implementation only in analog and / or digital circuit systems);

[0299] (b) A combination of hardware circuits and software, such as:

[0300] (i) a combination of analog and / or digital hardware circuitry and software / firmware, and

[0301] (ii) any portion of a hardware processor (including a digital signal processor), software and memory with software that works together to enable a device such as a communication device or base station to perform the various functions described above, and

[0302] (c) Hardware circuits and / or processors (such as a microprocessor or portion of a microprocessor) that require software (such as firmware) for operation, but the software may not be present when it is not needed for operation.

[0303] This definition of circuitry applies to all uses of the term "component" herein, including in any claims. As another example, as used herein, the term circuitry also covers implementations of only a hardware circuit or processor (or multiple processors) or portions of a hardware circuit or processor and their (or their) accompanying software and / or firmware. The term circuitry also covers, for example, an integrated device. The term circuitry also covers, for example and where applicable to a particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device, or a similar integrated circuit in a server, cellular network device, or other computing or network device.

[0304] The foregoing description has provided a complete and informative description of some examples of the present disclosure by way of exemplary and non-limiting and illustrative examples. However, various modifications and adaptations will become apparent to those skilled in the relevant art when the foregoing description is read in conjunction with the accompanying drawings and claims. However, all such and similar modifications to the teachings will still fall within the scope of the present disclosure.

Claims

1. A device comprising: means for determining a communication request associated with relay discovery and selection for a User Equipment to Network (U2N) relay connection establishment for a first User Equipment (UE); as well as A component for providing the communication request to the U2N relay UE via at least one first user equipment to user equipment U2U relay UE based on the communication request, using a relay chain established between the U2N relay UE and a second UE via the at least one first U2U relay UE.

2. A device comprising: means for initiating a communication request associated with relay discovery and selection for a user equipment to network (U2N) relay connection establishment for a first user equipment (UE), wherein the communication request is a request for a connection between the first UE and a U2N relay UE via at least one first user equipment to user equipment (U2U) relay UE, wherein the communication request indicates that the at least one first U2U relay UE is allowed to perform relay selection for the connection; and Means for providing the communication request to the at least one U2U relay UE.

3. A device comprising: A means for receiving a communication request associated with relay discovery and selection from a user equipment to user equipment (U2U relay user equipment) UE, wherein the communication request is a request for a connection between a first UE and a user equipment to network (U2N relay UE) via at least one U2U relay UE, wherein the communication request indicates that the at least one U2U relay UE is allowed to perform relay selection for the connection; and means for providing, based on the communication request, a response to the communication request to the first UE via the U2U relay UE.

4. The device according to claim 3, wherein: The means for providing a response to the communication request to the first UE via the U2U relay UE based on the communication request includes: means for determining, based on the communication request, whether to respond using one of: an accept message associated with the communication request, a reject message associated with the communication request, or a relay discovery message associated with the communication request; and means for providing the response to the first UE via the U2U relay UE based on the determination.

5. The device according to claim 4, wherein: When determining to provide a rejection message associated with the communication request, the apparatus comprises: means for including in the response a reject flag together with the reject message associated with the communication request, wherein the reject flag indicates that the reject message was initiated by the U2N relay UE.

6. The device according to claim 4 or claim 5, wherein: When it is determined to respond using the relay discovery message associated with the communication request, the apparatus includes: a component for selecting one or more U2U relay UEs from the at least one U2U relay UE; and a component for separately sending the response to the selected one or more U2U relay UEs.

7. The device according to any one of claims 3 to 6, wherein: One of the following: the apparatus is used for the U2N relay UE, the apparatus is included in the U2N relay UE, or the apparatus is the U2N relay UE.

8. A method comprising: determining a communication request associated with relay discovery and selection for a user equipment to network (U2N) relay connection establishment for a first user equipment (UE); as well as Based on the communication request, the communication request is provided to the U2N relay UE via at least one first user equipment to user equipment U2U relay UE, using a relay chain established between the U2N relay UE and a second UE via the at least one first U2U relay UE.

9. A method comprising: initiating a communication request associated with relay discovery and selection for a user equipment to network U2N relay connection establishment for a first user equipment UE, wherein the communication request is a request for a connection between the first UE and a U2N relay UE via at least one first user equipment to user equipment U2U relay UE, wherein the communication request indicates that the at least one first U2U relay UE is allowed to perform relay selection for the connection; and The communication request is provided to the at least one U2U relay UE.

10. A method comprising: receiving a communication request associated with relay discovery and selection from a user equipment to user equipment (U2U) relay user equipment (UE), wherein the communication request is a request for a connection between a first UE and a user equipment to network (U2N) relay UE via at least one U2U relay UE, wherein the communication request indicates that the at least one U2U relay UE is allowed to perform relay selection for the connection; and Based on the communication request, a response to the communication request is provided to the first UE via the U2U relay UE.

11. A computer program comprising instructions which, when executed by a device, cause the device to perform at least the following operations: determining a communication request associated with relay discovery and selection for a user equipment to network (U2N) relay connection establishment for a first user equipment (UE); and Based on the communication request, the communication request is provided to the U2N relay UE via at least one first user equipment to user equipment U2U relay UE, using a relay chain established between the U2N relay UE and a second UE via the at least one first U2U relay UE.

12. A computer program comprising instructions which, when executed by a device, cause the device to perform at least the following operations: Initiating a communication request associated with relay discovery and selection for a user equipment to network U2N relay connection establishment for a first user equipment UE, wherein: The communication request is a request for a connection between the first UE and a U2N relay UE via at least one first user equipment to user equipment U2U relay UE, wherein the communication request indicates that the at least one first U2U relay UE is allowed to perform relay selection for the connection; and The communication request is provided to the at least one U2U relay UE.

13. A computer program comprising instructions which, when executed by a device, cause the device to perform at least the following operations: A U2U relay from a user equipment to a user equipment UE receives a communication request associated with relay discovery and selection, wherein: The communication request is a request for a connection between the first UE and a User Equipment to Network (U2N) relay UE via at least one U2U relay UE, wherein the communication request indicates that the at least one U2U relay UE is allowed to perform relay selection for the connection; and Based on the communication request, a response to the communication request is provided to the first UE via the U2U relay UE.

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