Discovery and path selection for multi-hop relays

Abstract

A method includes receiving, by a first user equipment (UE), a first message from a second UE, including an indication of a request for multi-hop relaying, and first criteria for communicating via multi-hop relaying. A determination is performed to transmit the first message to a third UE. At least one criterion is generated of a second criteria and the first message is updated with the at least one criterion of the second criteria and the performance information of the first UE and transmitted to the third UE. The first UE receives a second message including information relating to a multi-hop relay to be established, the information relating to the multi-hop relay to be established including performance information for the third UE, and first selection information relating to the multi-hop relay to be established, updates and transmits the second message to the second UE.

Description

DISCOVERY AND PATH SELECTION FOR MULTI-HOP RELAYSFIELD

[0001] Various example embodiments relate generally to wireless networks and, more particularly, to a technique for discovery and path selection for multi-hop relays.BACKGROUND

[0002] Proximity Services (ProSe) is a device-to-device technology that allows devices to detect each other and to communicate directly. In user equipment (UE)-to-UE communication and UE-to-network communication, there are intermediate nodes that can be involved in a relay of a communication from a remote UE to a target UE or a network node (e.g., base station (BS)). Selecting the appropriate intermediate node(s) in a path between a remote UE and a target node (e.g., another UE or a network node), as well as maintaining the connection between the remote UE and the target node that may be subject to failure due to, for example, the mobility / failure of individual relay UEs, is challenging.SUMMARY

[0003] In an aspect of the present disclosure, a method includes receiving, by a first user equipment (UE), a first message from a second UE, the first message includes an indication of a request for multi-hop relaying, and first criteria for communicating via multi-hop relaying. The performance information of the first UE is determined. A determination is performed to transmit the first message to a third UE, the determining based on the performance information of the first UE and based on the first criteria being satisfied. A determination is performed that at least one criterion of the first criteria should be updated. At least one criterion is generated of a second criteria based on the performance information of the first UE and the first message, the first message is updated with the at least one criterion of the second criteria and the performance information of the first UE, and the first message is transmitted, after the updating of the first message, to the third UE, by the first UE. The first UE receives, from the third UE, a second message comprising information relating to a multi-hop relay to be established, the information relating to the multi-hop relay to be established including performance information for the thirdUE, and first selection information relating to the multi-hop relay to be established. The second message is updated by updating the first selection information with second selection information, and the first UE transmits to the second UE, the second message after the updating of the second message, the transmitting based on the performance information for the third UE and based on the first selection information being satisfied.

[0004] In an aspect of the method, the first criteria includes at least one criterion for extending or not extending the request for multi-hop relaying.

[0005] In an aspect of the method, the first criteria includes one or more of the following: radio link condition parameters, congestion parameters, quality of service (QoS) parameters, a maximum number of hops to a target device, a maximum duration of discovery procedure for multi-hop relaying, or a mobility profile of one or more candidate relay UEs.

[0006] In an aspect of the method, the radio link condition parameters include a threshold of a measured sidelink discovery reference signal received power (SD-RSRP).

[0007] In an aspect of the method, the congestion parameters include a threshold of a measured channel busy ration (CBR) value.

[0008] In an aspect of the method, the QoS parameters include one or more of the following: threshold of data rate, threshold of delay, or packet loss.

[0009] In an aspect of the method, the mobility profile of one or more candidate relay UEs include one or more of the following: a speed threshold of the one or more candidate relay UEs, a direction of the one or more candidate relay UEs, or a destination of the one or more candidate relay UEs.

[0010] In an aspect of the method, the performance information of the first UE includes parameters for communicating via multi-hop relaying.

[0011] In an aspect of the method, the second criteria include any one of the following: a location information of the first UE, timing information of the first UE, or mobility information of the first UE.

[0012] In an aspect of the method, the second criteria include any one of the following: measured radio link parameters, congestion parameters, mobility profile of the first UE, or QoS parameters at the first UE.

[0013] In an aspect of the method, the second criteria include an estimated QoS of the multihop path up to the first UE.

[0014] In an aspect of the method, the method further includes receiving, by the first UE, one or more other messages distinct from the first message, wherein each message of the one or more other messages includes an indication of a request for multi-hop relaying.

[0015] In an aspect of the method, the method further includes waiting, by the first UE, a predefined time for the receiving the one or more other messages; and determining which among the first message and the one or more other message is to be transmitted to the third UE.

[0016] In an aspect of the method, the first UE transmits the second message to the second UE based on the third criteria satisfying the first criteria.

[0017] In an aspect of the method, the method further includes receiving, by the first UE, one or more other messages distinct from the second message, wherein each message of the one or more other messages includes information relating to a multi-hop relay to be established.

[0018] In an aspect of the method, the method further includes waiting, by the first UE, a predefined time for the receiving the one or more other messages; and determining which among the second message and the one or more other messages is to be transmitted to the second UE.

[0019] In an aspect of the method, the first selection information includes the third criteria.

[0020] In an aspect of the method, the first selection information includes one or more of the following: an identifier of a candidate relay UE, measured radio link condition parameters, congestion parameters, QoS parameters at the candidate relay UE, a location of the candidate relay UE, or mobility information of the first UE.

[0021] In an aspect of the present disclosure, a user equipment includes at least one processor, and at least one memory storing instructions which, when executed by the at least one processor, cause the user equipment at least to perform any of the foregoing methods.

[0022] In an aspect of the present disclosure, a processor-readable medium storing instructions which, when executed by at least one processor of an apparatus, cause the apparatus at least to perform any of the foregoing methods.

[0023] According to some aspects, there is provided the subject matter of the independent claims. Some further aspects are defined in the dependent claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Some example embodiments will now be described with reference to the accompanying drawings.

[0025] FIG. 1 is a diagram of an example embodiment of wireless networking between a network system and a user equipment (UE) that includes multiple devices connected to the UE, according to one illustrated aspect of the disclosure;

[0026] FIG. 2 is a diagram of example components of a network system, according to one illustrated aspect of the disclosure;

[0027] FIG. 3A is a diagram of an example multi-hop communication between a remote UE and a target UE according to one illustrated aspect of the disclosure;

[0028] FIG. 3B is a diagram of an example multi-hop communication between a remote UE and network node according to one illustrated aspect of the disclosure;

[0029] FIG. 4 is a diagram of example signals and operations of a network system, according to one illustrated aspect of the disclosure; and

[0030] FIG. 5 is a diagram of example embodiment of components of a UE, connected device or of a network apparatus, according to one illustrated aspect of the present disclosure.DETAILED DESCRIPTION

[0031] In the following description, certain specific details are set forth in order to provide a thorough understanding of disclosed aspects. However, one skilled in the relevant art will recognize that aspects may be practiced without one or more of these specific details or with other methods, components, materials, etc. In other instances, well-known structures associated with transmitters, receivers, or transceivers have not been shown or described in detail to avoid unnecessarily obscuring descriptions of the aspects.

[0032] Reference throughout this specification to “one aspect” or “an aspect” means that a particular feature, structure, or characteristic described in connection with the aspect is included in at least one aspect. Thus, the appearances of the phrases “in one aspect” or “in an aspect” in various places throughout this specification are not necessarily all referring to the same aspect. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more aspects.

[0033] Embodiments described in the present disclosure may be implemented in wireless networking apparatuses, such as, without limitation, apparatuses utilizing Worldwide Interoperability for Microwave Access (WiMAX), Global System for Mobile communications (GSM, 2G), GSM EDGE radio access Network (GERAN), General Packet Radio Service (GRPS),Universal Mobile Telecommunication System (UMTS, 3G) based on basic wideband-code division multiple access (W-CDMA), high-speed packet access (HSPA), Long Term Evolution (LTE), LTE- Advanced, enhanced LTE (eLTE), 5G New Radio (5G NR), 5G Advance, 6G (and beyond) and 802.1 lax (Wi-Fi 6), among other wireless networking systems. The term ‘eLTE’ here denotes the LTE evolution that connects to a 5G core. LTE is also known as evolved UMTS terrestrial radio access (EUTRA) or as evolved UMTS terrestrial radio access network (EUTRAN).

[0034] The present disclosure may use the term “serving network device” to refer to a network node or network device (or a portion thereof) that services a UE. As used herein, the terms “transmit to,” “receive from,” and “cooperate with,” (and their variations) include communications that may or may not involve communications through one or more intermediate devices or nodes. The term “acquire” (and its variations) includes acquiring in the first instance or reacquiring after the first instance. The term “connection” may mean a physical connection or a logical connection.

[0035] The present disclosure uses 5G NR as an example of a wireless network and may use smartphones as an example of UEs. It is intended and shall be understood that such examples are merely illustrative, and the present disclosure is applicable to other wireless networks and user equipment.

[0036] FIG. 1 is a diagram depicting an example of wireless networking between a network system 100 and a user equipment (UE) 150. The network system 100 may include one or more network nodes 120, one or more servers 110, and / or one or more network equipment 130 (e.g., test equipment). The network nodes 120 will be described in more detail below. As used herein, the term “network apparatus” may refer to any component of the network system 100, such as the server 110, the network node 120, the network equipment 130, any component(s) of the foregoing, and / or any other component(s) of the network system 100. Examples of network apparatuses include, without limitation, apparatuses implementing aspects of 5G NR, among others. The present disclosure describes embodiments related to 5GNR and embodiments that involve aspects defined by 3rd Generation Partnership Project (3GPP). However, it is contemplated that embodiments relating to other wireless networking technologies are encompassed within the scope of the present disclosure.

[0037] The network system 100 may include one or more network nodes 120, one or more servers 110, and / or one or more network equipment 130 (e.g., test equipment). The network nodes 120 will be described in more detail below. As used herein, the term “network apparatus” mayrefer to any component of the network system 100, such as the server 110, the network node 120, the network equipment 130, any component(s) of the foregoing, and / or any other component(s) of the network system 100. Examples of network apparatuses include, without limitation, apparatuses implementing aspects of 5G NR, among others. The present disclosure describes embodiments related to 5G NR and embodiments that involve aspects defined by 3rd Generation Partnership Project (3 GPP). However, it is contemplated that embodiments relating to other wireless networking technologies are encompassed within the scope of the present disclosure.

[0038] The following description provides further details of examples of network nodes. In a 5G NR network, a gNodeB (also known as gNB) may include, e.g., a node that provides NR user plane and control plane protocol terminations towards the UE and that is connected via a NG interface to the 5G core (5GC), e.g., according to 3GPP TS 38.300 V16.6.0 (2021-06) section 3.2, which is hereby incorporated by reference herein.

[0039] A gNB supports various protocol layers, e.g., Layer 1 (LI) - physical layer, Layer 2 (L2), and Layer 3 (L3).

[0040] The layer 2 (L2) of NR is split into the following sublayers: Medium Access Control (MAC), Radio Link Control (RLC), Packet Data Convergence Protocol (PDCP) and Service Data Adaptation Protocol (SDAP), where, e.g.: o The physical layer offers to the MAC sublayer transport channels; o The MAC sublayer offers to the RLC sublayer logical channels; o The RLC sublayer offers to the PDCP sublayer RLC channels; o The PDCP sublayer offers to the SDAP sublayer radio bearers; o The SDAP sublayer offers to 5GC quality of service (QoS) flows; o Control channels include broadcast control channel (BCCH) and physical control channel (PCCH).

[0041] Layer 3 (L3) includes, e.g., radio resource control (RRC), e.g., according to 3GPP TS 38.300 VI 6.6.0 (2021-06) section 6, which is hereby incorporated by reference herein.

[0042] A gNB central unit (gNB-CU) includes, e.g., a logical node hosting, e.g., radio resource control (RRC), service data adaptation protocol (SDAP), and packet data convergence protocol (PDCP) protocols of the gNB or RRC and PDCP protocols of the en-gNB, that controls the operation of one or more gNB distributed units (gNB-DUs). The gNB-CU terminates the Flinterface connected with the gNB-DU. A gNB-CU may also be referred to herein as a CU, a central unit, a centralized unit, or a control unit.

[0043] A gNB Distributed Unit (gNB-DU) includes, e.g., a logical node hosting, e.g., radio link control (RLC), media access control (MAC), and physical (PHY) layers of the gNB or en- gNB, and its operation is partly controlled by the gNB-CU. One gNB-DU supports one or multiple cells. One cell is supported by only one gNB-DU. The gNB-DU terminates the Fl interface connected with the gNB-CU. A gNB-DU may also be referred to herein as DU or a distributed unit.

[0044] As used herein, the term “network node” may refer to any of a gNB, a gNB-CU, or a gNB-DU, or any combination of them. A RAN (radio access network) node or network node such as, e.g., a gNB, gNB-CU, or gNB-DU, or parts thereof, may be implemented using, e.g., an apparatus with at least one processor and / or at least one memory with processor-readable instructions (“program”) configured to support and / or provision and / or process CU and / or DU related functionality and / or features, and / or at least one protocol (sub-)layer of a RAN (radio access network), e.g., layer 2 and / or layer 3. Different functional splits between the central and distributed unit are possible. An example of such an apparatus and components will be described in connection with FIG. 5 below.

[0045] The gNB-CU and gNB-DU parts may, e.g., be co-located or physically separated. The gNB-DU may even be split further, e.g., into two parts, e.g., one including processing equipment and one including an antenna. A central unit (CU) may also be called baseband unit / radio equipment controller / cloud-RAN / virtual-RAN (BBU / REC / C-RAN / V-RAN), open-RAN (O- RAN), or part thereof. A distributed unit (DU) may also be called remote radio head / remote radio unit / radio equipment / radio unit (RRH / RRU / RE / RU), or part thereof. Hereinafter, in various example embodiments of the present disclosure, a network node, which supports at least one of central unit functionality or a layer 3 protocol of a radio access network, may be, e.g., a gNB-CU. Similarly, a network node, which supports at least one of distributed unit functionality or a layer 2 protocol of the radio access network, may be, e.g., a gNB-DU.

[0046] A gNB-CU may support one or multiple gNB-DUs. A gNB-DU may support one or multiple cells and, thus, could support a serving cell for a user equipment (UE) or support a candidate cell for handover, dual connectivity, and / or carrier aggregation, among other procedures.

[0047] The user equipment (UE) 150 may be or include a wireless or mobile device, an apparatus with a radio interface to interact with a RAN (radio access network), a smartphone, an in-vehicle apparatus, an loT device, or a M2M device, among other types of user equipment. Such UE 150 may include: at least one processor; and at least one memory including program code; where the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to perform certain operations, such as, e.g., RRC connection to the RAN. An example of components of a UE will be described in connection with FIG. 5. In embodiments, the UE 150 may be configured to generate a message (e.g., including a cell ID) to be transmitted via radio towards a RAN (e.g., to reach and communicate with a serving cell). In embodiments, the UE 150 may generate and transmit and receive RRC messages containing one or more RRC PDUs (packet data units). Persons skilled in the art will understand RRC protocol as well as other procedures a UE may perform.

[0048] With continuing reference to FIG. 1, in the example of a 5G NR network, the network system 100 provides one or more cells, which define a coverage area of the network system 100. As described above, the network system 100 may include a gNB of a 5G NR network or may include any other apparatus configured to control radio communication and manage radio resources within a cell. As used herein, the term “resource” may refer to radio resources, such as a resource block (RB), a physical resource block (PRB), a radio frame, a subframe, a time slot, a sub-band, a frequency region, a sub-carrier, a beam, etc. In embodiments, the network node 120 may be called a base station.

[0049] FIG. 1 provides an example and is merely illustrative of a network system 100 and a UE 150. Persons skilled in the art will understand that the network system 100 includes components not illustrated in FIG. 1 and will understand that other user equipment may be in communication with the network system 100.

[0050] FIG. 2 is a block diagram of example components of the network system 100 of FIG. 1. A 5G NR network may be described as an example of the network system 100, and it is intended that aspects of the following description shall be applicable to other types of network systems, as well. The network system may operate in accordance with the signals and connections shown in FIG. 1 such that the UE 150 is in communication with the network system 100 through the radio access network 225. Additionally, the network system may be divided into user plane components and functions and control plane components and functions, as shown and described herein. Unlessindicated otherwise, the terms “component”, “function”, and “service” may be used interchangeably herein, and they may refer to and be implemented by instructions executed by one or more processors.

[0051] Example functions of the components are described below. The example functions are merely illustrative, and it shall be understood that additional operations and functions may be performed by the components described herein. Additionally, the connections between components may be virtual connections over service-based interfaces such that any component may communicate with any other component. In this manner, any component may act as a service “producer,” for any other component that is a service “consumer,” to provide services for network functions.

[0052] For example, a core network 210 is described in the control plane of the network system. The core network 210 may include an authentication server function (AUSF) 211, an access and mobility function (AMF) 212, and a session management function (SMF) 213. The core network 210 may also include a network slice selection function (NSSF) 214, a network exposure function (NEF) 215, a network repository function (NRF) 216, and a unified data management function (UDM) 217, which may include a uniform data repository (UDR) 224.

[0053] Additional components and functions of the core network 210 may include an application function (AF) 218, policy control function (PCF) 219, network data analytics function (NWDAF) 220, analytics data repository function (ADRF) 221, management data analytics function (MDAF) 222, and operations and management function (0AM) 223.

[0054] The user plane includes the UE 150, a radio access network (RAN) 225, a user plane function (UPF) 226, and a data network (DN) 227. The RAN 225 may include one or more components described in connection with FIG. 1, such as one or more network nodes. However, the RAN 225 may not be limited to such components. The UPF 226 provides connection for data being transmitted over the RAN 225. The DN 226 identifies services from service providers, Internet access, and third party services, for example.

[0055] The AMF 212 processes connection and mobility tasks. The AUSF 211 receives authentication requests from the AMF 212 and interacts with UDM 217 to authenticate and validate network responses for determination of successful authentication. The SMF 213 conducts packet data unit (PDU) session management, as well as manages session context with the UPF 226.

[0056] The NSSF 214 may select a network slicing instance (NSI) and determine the allowed network slice selection assistance information (NSSAI). This selection and determination is utilized to set the AMF 212 to provide service to the UE 150. The NEF 215 secures access to network services for third parties to create specialized network services. The NRF 216 acts as a repository to store network functions to allow the functions to register with and discover each other.

[0057] The UDM 217 generates authentication vectors for use by the AUSF 211 and ADM 212 and provides user identification handling. The UDM 217 may be connected to the UDR 224 which stores data associated with authentication, applications, or the like. The AF 218 provides application services to a user (e.g., streaming services, etc.). The PCF 219 provides policy control functionality. For example, the PCF 219 may assist in network slicing and mobility management, as well as provide quality of service (QoS) and charging functionality.

[0058] The NWDAF 220 collects data (e.g., from the UE 150 and the network system) to perform network analytics and provide insight to functions that utilize the analytics in the providing of services. The ADRF 221 allows the storage, retrieval, and removal of data and analytics by consumers. The MDAF 222 provides additional data analytics services for network functions. The 0AM 223 provides provisioning and management processing functions to manage elements in or connected to the network (e.g., UE 150, network nodes, etc.).

[0059] FIG. 2 is merely an example of components of a network system, and variations are contemplated to be within the scope of the present disclosure. In embodiments, the network system may include other components not illustrated in FIG. 2. In embodiments, the network system may not include every component illustrated in FIG. 2. In embodiments, the components and connections may be implemented with different connections than those illustrated in FIG. 2. Such and other embodiments are contemplated to be within the scope of the present disclosure.

[0060] In order to extend network coverage in a wireless communication system, improve connection range, and / or to improve quality of service (QoS) for wireless communications, communication / messaging between UEs in the network may be utilized. Proximity Services (ProSe) is a device-to-device technology that allows devices to detect each other and to communicate directly. For example, in some cases, a UE may not be located within a desirable range of a network apparatus (e.g., base station). Accordingly, in such a situation, the UE maytransmit its messages through one or more additional UEs for eventual transmission to the network. The UE-UE messaging may be referred to as “ProSe” communication, or ProSe messaging.

[0061] To effect such ProSe messaging, various example techniques may be utilized. In one example, single-hop ProSe messaging may be utilized that includes enabling sidelink (e.g., PC5) communication between two remote UEs via a relay UE, the single hop referring to the communication passing via a single relay UE. In another example, ProSe single-hop UE to network relaying may be utilized, which may enable indirect communication between a network device (e.g., 5G network) and UEs via a relay UE. For example, for UEs that are out of coverage of the network, providing the relaying functionality may support connectivity to the network for a ProSe remote UE.

[0062] Another example technique for ProSe messaging may include multi-path (MP) singlehop UE to network relay UEs. In this example, using one direct network communication path and one indirect relayed network communication path via a UE to network relay UE may be used to improve reliability or data rates for the remote UE that is transmitting / receiving messages with the network. A multi-path relay UE may include example configurations such as, duplicated connectivity, where the same data packets are transmitted over both paths to ensure the required reliability (e.g., packet loss, bit error rate (BER)), split connectivity, where the data packets are split between the different paths that constitute the multi-path and the goal is to increase the throughput (e.g., data rate), and / or resiliency in using an alternative transmission path if a current transmission path becomes unusable.

[0063] As used herein, the term “initiating UE” and “remote UE” may refer to a UE initiating a request for multi-path communication. The term “target UE” and “UE-to-NW relay” may refer to a UE that can potentially serve as a UE that provides a connection to the network for a remote UE. The terms “UE-to-UE Relay” and “Relay UE” may refer to an intermediate UE that communicates with another UE in a communication path between a remote UE and a target UE. The term “candidate UE” may refer to a UE that may be considered a candidate for inclusion in a communication path between the remote UE and the network. A candidate UE, in various embodiments, may include a relay UE or a target UE.

[0064] As used herein, the term “hop” may refer to a communication path between a single pair of UEs in communication chain. For example, in various embodiments, the term “first hop”may refer to the communication path between a remote UE and a relay UE, and so on, where an “wth hop” may refer to a hop between a relay UE and an eventual target UE.

[0065] With respect to an example embodiment of multi-hop communication, FIG. 3A is a diagram of an example multi-hop path 300A between a remote UE and a target UE according to one illustrated aspect of the disclosure. FIG. 3B is a diagram of an example multi-hop path 300B between a remote UE and base station according to one illustrated aspect of the disclosure.

[0066] As shown in FIG. 3 A, a plurality of UEs 150 may be in communication with one another over, for example, a PC5 interface. In some example embodiments, a UE 150 may be a remote UE initiating communication to a target UE via one or more intermediary UEs (referred to also as relay UEs). The relay UEs may receive communications from one another and transmit the communications to another relay UE as part of a communication chain from the remote UE initiating communication to the target UE.

[0067] Similar to FIG. 3 A, FIG. 3B depicts a plurality of UEs 150 that may be in communication with one another over, for example, a PC5 interface. In some example embodiments, the UE 150 may be a remote UE initiating communication to a network node (e.g., base station) 120 via one or more intermediary UEs (relay UEs). The relay UEs may receive communications from one another and transmit the communications to another relay UE as part of a communication chain from the remote UE initiating communication to the base station 120. The terms “path”, “multi-hop path”, and “multi-hop relay” may be used interchangeably and refer to a plurality of intermediate relay UEs through which communications pass while traversing from a remote UE initiating the communications to a target UE or network node, with each hop being passage via a relay UE.

[0068] Accordingly, in multi-hop UE-to-UE relay communication and UE-to-network relay communication, there may exist multiple intermediate nodes (e.g., relay UEs) that may receive and re-transmit a message from a remote UE to the target UE or network node. Selecting the appropriate intermediate node(s) in a path between a remote UE and a target node (e.g., another UE or a network node), as well as maintaining the connection between the remote UE and the target node that may be subject to failure due to, for example, the mobility / failure of individual relay UEs, is challenging. Accordingly, features relating to UE-to-UE relays (i.e., UEs that act as relay between a first UE and a second UE) and UE-to-network (NW) relays (i.e., UEs that act as relay between a first UE and a network node) may aid in establishing connections during a pathdiscovery process. It may therefore be beneficial to select appropriate intermediate nodes (e.g., relay UE or relay UEs) as well as to maintain the connection between a remote UE and a target node (e.g., another UE or a network node), which is established over more than one relay hops, in order to minimize the impact of the mobility and / or failure of individual relay UEs in the communication chain.

[0069] The following description refers to criteria relating to the discovery process of multihop relaying, performance information of UEs, and selection information relating to the path selection process of a multi-hop relay to be established. Certain aspects of the criteria, performance information, and selection information may overlap. For example, certain parameters, measurements, or quantities may be performance information for a UE, may be involved in a criterion for a path discovery process, and / or may be selection information for a path selection process. Accordingly, unless stated otherwise, any parameter, measurement, and / or quantity described herein may be criteria for a discovery process, may be performance information of a UE, and / or may be selection information for a path selection process.

[0070] Accordingly, for effective multi -hop communication, the path discovery process may take into consideration features that multi-hop relays have in order to increase the effectiveness of the discovery process. In various embodiments, it may be desirable to reduce unnecessary forwarding of discovery solicitation and response messages in all possible directions so as to avoid flooding issues and preserve resources, signaling, and time for the establishment of multi-hop relays. In various embodiments, determining, or considering, the stability of multi-hop paths during the discovery process may avoid the need for continuous re-establishments of multi-hop relays. In various embodiments, path discovery may include discovering one or more possible communication paths between an initiating UE and a target UE that the initiating UE would like to communicate with to access a network. In various embodiments, a path discovery process may include a determination of multiple paths between an initiating UE and a target UE to determine one of the multiple paths for communication.

[0071] Therefore, various example embodiments are described herein directed toward “on- the-fly” and hop-by-hop adaptation of criteria for a multi-hop relay discovery procedure for a discovery solicitation message in the direction from an initiator UE (e.g., remote UE) toward a UE-to-network relay UE (UE-to-NW relay UE) or UE-to-UE relay UE in what may be described as an “uplink” communication direction. In various example embodiments, hop-by-hop adaptationof criteria for a multi-hop relay path selection procedure for discovery response messages are described herein, in the direction from the UE-to-NW relay UE or UE-to-UE relay UE toward the remote UE in what may be described as a “downlink” communication direction. In various embodiments, the direction may be described by a set of locations, by a trajectory, and / or by a location area. In various embodiments, a reduction of unnecessary forwarding of the discovery solicitation and response messages and avoiding of flooding issues may be effected, increasing multi-hop path robustness.

[0072] As used herein, the term “signals” may refer to communication signals between the UE 150 as well as communication signals between the UE 150 and the network system 100. In addition, the term “signals” may refer to communication signals between components resident in a single device, such as signals between components resident with the UE 150, or signals between components resident in one of the devices 160. Persons skilled in the art will understand that the term “signals” may refer to additional communication signals between components of a single device / apparatus or between multiple devices / apparatuses and that signals may encompass a variety of example transmission techniques, including, but not limited to radio frequency (RF) signals, electrical signals, and / or electromagnetic (EM) radiation signals.

[0073] As used herein, the term “downlink” may refer to flow of information toward a remote UE. The term “uplink” may refer to flow of information from the remote UE. As used herein “relay” and “relay UE” may be used interchangeably.

[0074] FIG. 4 is a diagram of example signals and operations of a network system 400, according to one illustrated aspect of the disclosure. The following paragraphs will describe various signals and operations. It will be understood that a described signal may have associated operations performed with respect to the described signal and a described operation may have associated signals in performance of the described operation.

[0075] At operation 401.1, the remote UE initiates a multi-hop UE-to-network discovery procedure. In various embodiments, the remote UE may set a waiting timer (Tin) to wait for reception of multi-hop discovery messages at operation 401.2. The waiting timer may indicate a maximum amount of time the remote UE will wait before discontinuing the multi-hop UE-to- network discovery procedure. While FIG. 4 is described in the context of a multi-hop UE-to- network discovery procedure, similar procedures may be utilized in a multi-hop UE-to-UE discovery procedure.

[0076] At operation 402, the remote UE transmits a UE-to-network relay discovery solicitation message to at least one UE-to-UE relay UE and the at least one UE-to-UE relay UE receives the discovery solicitation message. In various embodiments, the discovery solicitation message is broadcast by the remote UE and may be received by more than one UE-to-UE relay UE. In various embodiments, the discovery solicitation message includes criteria for communicating via multihop relaying. In various embodiments, for example, the discovery solicitation message may indicate that multi-hop relays are allowed and include the UE-to-NW relay service code (RSC) for UE-to-NW relay UE communication and may include the identifiers (IDs) of authorized public land mobile networks (PLMNs) of the remote UE.

[0077] In various embodiments, the discovery solicitation message may include information to enable a UE (or UEs) to facilitate an enhanced discovery process and reduce flooding issues by providing criteria in the discovery solicitation message to aid an intermediary UE (e.g., UE-to-UE relay UE) or a target UE (e.g., UE-to-NW relay UE) to determine a communication path between an initiating UE and the target UE. In various embodiments, the discovery solicitation message may be pre-configured to UEs based on a capability of those UEs. In various embodiments, the information may include criteria such as a descriptor / configuration of a multi-hop relay. For example, the criteria and / or performance information may include the type of requested multi-hop relay, requirements such as QoS requirements, priority in latency formation, location and / or mobility profile of the initiator (remote) UE and timing information corresponding to the time the multi-hop UE-to-network relay discovery procedure is initiated.

[0078] In various embodiments, criteria for communicating via multi-hop relaying may be included in the discovery solicitation message including criteria and / or information relating to extending or not extending the multi-hop discovery procedure. For example, in various embodiments, the criteria may include a sidelink radio link condition (e.g., threshold of measured sidelink discovery reference signal received power (SD-RSRP) at the receiving UE (e.g., at the candidate relay UE) related to a transmitting UE. The criteria may include different thresholds for each hop (e.g., in the case that a more robust link is required at specific part (e.g., one or more hops) of the path). The criteria may also include, in various embodiments, a threshold sidelink congestion (e.g., threshold of measured channel busy ration (CBR) values at the candidate relay UE), a sidelink QoS threshold (e.g., threshold of data rate, packet loss, and / or threshold delay - whether locally, cumulatively, or both locally and cumulatively), a maximum number of hops fromthe remote UE up to the target node (e.g., UE-to-NW / UE-to-UE relay UE), a maximum duration of discovery time for the multi-hop relay, and / or a mobility profile of a candidate relay UE (e.g., speed of candidate UEs, direction or the destination of a candidate UE). In various embodiments, a candidate relay UE may include a relay UE that may be a candidate to form part of or be in a communication path between the initiating UE and the target UE, based on the candidate UE’s ability to meet the criteria provided in the discovery solicitation message (or updated discovery solicitation message as described below).

[0079] At operation 403, a relay UE that receives the discovery solicitation message from the remote UE (e.g., 1sthop) determines whether to forward the discovery solicitation message. In various embodiments, the UE-to-UE relay UE at the first hop determines its availability to undertake the role of a relay UE in a multi-hop path for the remote UE to the target. That is, a relay UE that receives the discovery solicitation message determines whether it should forward the discovery solicitation message. In various embodiments, the determination may be based on the ability of relay UE to satisfy the criteria included in the discovery solicitation message received from the remote UE. For example, the 1sthop UE-to-UE relay determines whether the sidelink radio thresholds, sidelink congestion thresholds, sidelink QoS thresholds, maximum number of hops for the multi-hop relay, the maximum duration of discovery time for the multi-hop relay, mobility profile of involved UEs set forth in the criteria received from the remote UE can be satisfied.

[0080] In various embodiments, the 1sthop UE-to-UE relay may use its measured radio and / or congestion parameters (e.g., performance information of the 1sthop UE-to-UE relay) and compare them with received criteria (e.g., RSRP is above a threshold or CBR below a threshold) to decide if it should extend the discovery process.

[0081] If the 1sthop UE-to-UE relay determines to extend the discovery solicitation message, at operation 404, the 1sthop UE-to-UE relay updates the discovery solicitation message with additional criteria and transmits the updated discovery solicitation message to one or more 2ndhop UE-to-UE relays, and the one or more 2ndhop UE-to-UE relays receive the updated discovery solicitation message. It should be noted that in various embodiments, the updated discovery solicitation message is a broadcast message and may be received by more than one 2ndhop UE-to UE relays.

[0082] In various embodiments, the updated information included in the updated discovery solicitation message may include the identifier of the remote UE, a UE-to-NW RSC, the descriptor / configuration of the multi-hop relay, criteria for deciding extending or not extending the multi-hop discovery procedure, based on the updated information from the 1sthop UE-to-UE relay. In various embodiments, the information may include an identifier of 1sthop UE-to-UE relay UE, location and timing information that a candidate relay UE decides to extend the discovery procedure, measured radio link information, congestion, QoS parameters (e.g., performance information of the 1sthop UE-to-UE relay), at the 1sthop UE-to-UE relay UE, and / or estimated QoS of the path up to this point in the multi-hop discovery procedure.

[0083] As mentioned above, since multiple 1sthop UE-to-UE relays may be receiving the discovery solicitation message from the remote UE, each 1sthop UE-to-UE relay UE may perform operations 403 and 404.

[0084] At operation 405, the 2ndhop UE-to-UE relay UE determines whether to forward the discovery solicitation message received from the 1sthop UE-to-UE relay UE. In various embodiments, the 2ndhop UE-to-UE relay UE may utilize a similar determination as described above for the 1sthop UE-to-UE relay UE. That is, the 2ndhop UE-to-UE relay UE may perform comparisons and measurements (e.g., using performance information of the 2ndhop UE-to-UE relay) similar to those described at operation 403 from the perspective of the 2ndhop UE-to-UE relay UE.

[0085] If the 2ndhop UE-to-UE relay UE determines to extend the discovery solicitation message, at operation 406, the 2ndhop UE-to-UE relay UE updates the discovery solicitation message with additional or different criteria and transmits the updated discovery solicitation message to one or more next hop (e.g., nthhop) UE-to-UE relays, and the one or more nthhop UE- to-UE relays receive the updated discovery solicitation message. In various embodiments, updating the discovery solicitation message may involve adding at least one criterion, replacing at least one criterion with at least one different criterion, modifying at least one criterion, and / or deleting at least one criterion. It should be noted that in various embodiments, the updated discovery solicitation message is a broadcast message and may be received by more than one nthhop UE-to-UE relays. Although the nthhop UE-to-UE relay UEs shown in FIG. 4 are, for example, 3rdhop UE-to-UE relays, it should be noted that the nthhop UE-to-UE relay UEs may be at any point in the multi-hop path.

[0086] In various example embodiments, the 2ndhop UE-to-UE relay UE may receive multiple updated discovery solicitation messages from multiple 1sthop UE-to-UE relay UEs. In order to reduce the number of transmitted messages, the 2ndhop UE-to-UE relay UE may apply one or more of the following procedures: transmits, only once, the multi-hop UE-to-network relay discovery solicitation message the first time it has received a solicitation message from another UE (e.g., the first 1sthop UE-to-UE relay UE it receives the message from), waits for a time Tu (i.e., from the moment that it received the first discovery solicitation message) to receive other multi-hop UE-to-network relay discovery solicitation messages, before deciding which previous relay IDs could be added as information for the next transmission, and / or retransmits a maximum number (Max Txs) of discovery solicitation messages, according to the transmission criteria (e.g., lowest number of hops, in the range of measured SL / SD-RSRP at the last hop, measured radio and / or congestion and / or QoS parameters, timing, etc.).

[0087] Further, in various embodiments the updated discovery solicitation message transmitted at operation 406 includes information from the perspective of the 2ndhop UE-to-UE relay UE. For example, the updated discovery solicitation message transmitted at operation 406 includes information similar to the information at operation 404, but from the perspective of the 2ndhop UE-to-UE relay UE.

[0088] As mentioned above, since multiple 2ndhop UE-to-UE relays may be receiving the discovery solicitation message from the 1sthop UE-to-UE relay UE, each 2ndhop UE-to-UE relay UE may perform operations 405 and 406.

[0089] As shown in FIG. 4, one or more nthhop UE-to-UE relay UEs receive the updated discovery solicitation message from the 2ndhop UE-to-UE relay. However, this is an example number of relays in the multi-hop path, and additional UE-to-UE relays may exist between the 2ndhop UE-to-UE relay and the nthhop UE-to-UE relay UE. Further, as shown in FIG. 4, the nthhop UE-to-UE relay UE is the UE-to-NW relay UE that includes a connection to the base station (BS) of the wireless network.

[0090] Accordingly, at operation 407, the nthhop UE-to-UE relay UE determines whether it meets the criteria of the received updated discovery solicitation message from the 2ndhop UE-to- UE relay UE. For example, in various embodiments, the nthhop UE-to-UE relay UE determines whether the RSC, any target information, and any other multi-hop criteria set by the remote UE(or pre-configured by the network (e.g., radio link parameters of PC5 and / or Uu interface), can be satisfied.

[0091] If the nthhop UE-to-UE relay UE determines that the criteria can be satisfied, at operation 408, the nthhop UE-to-UE relay UE transmits a discovery response message to the UE- to-UE relay (e.g., the 2ndhop UE-to-UE relay UE) and the UE-to-UE relay receives the discovery response message.

[0092] The discovery response message, in various embodiments, may include one or more of the following criteria and / or selection information: the type of discovery message, the remote UE (Discoverer) ID, discovery information (e.g., UE-to-NW relay ID) and RSC, a list of IDs of the candidate relay UEs that were traversed to reach the UE-to-NW relay UE, locations of each candidate relay UE in the list of candidate relay UEs that were traversed to reach the UE-to-NW relay UE, a total time of the discovery procedure, an estimated QoS of the multi-hop path, a measured PC5 Radio link (e.g., SL / SD-RSRP), congestion (e.g., CBR, CR) and QoS parameters (e.g., threshold data rate, packet loss, threshold delay) at the candidate UE-to-NW relay UE with the reception of the UE-to-network relay discovery solicitation message, Uu interface radio measurements (e.g., Uu RSRP), the location of the candidate UE-to-NW relay UE, and / or mobility information of UE-to-NW relay UE.

[0093] If the list of candidate relay UEs is provided by the UE-to-NW relay UE (with one candidate relay UE per hop), then, in various example embodiments, the discovery response message could be sent using the candidate relay UE’s L2 ID so that the response message is sent as unicast, instead of using a broadcast transmission and thus further reduce the flooding. In various examples, there may not be a need to have any determination steps for forwarding the discovery response message described below.

[0094] As mentioned above, each nthhop UE-to-UE relay UEs may receive multiple updated discovery solicitation messages from the same remote UE. Accordingly, in various embodiments, the UE-to-NW relay UE may determine which multi-hop UE-to-network relay discovery solicitation messages should be replied to with a discovery response message.

[0095] Accordingly, the UE-to-NW relay UE may apply one or more criteria and / or performance information, such as a lowest number of hops between the remote UE and the UE- to-NW relay UE, what measurements are in a certain range of measured SL / SD-RSRP and / or other criteria defined by the remote UE and / or the previous relay UE, among other possible criteria andperformance information. The UE-to-NW relay UE may define the list of the candidate relay UEs that the discovery response message should traverse to reach the remote UE where more than one path is available. One or more candidate relay UEs may be used for each hop, for example. In various embodiments, one or more UE-to-Network relay discovery response messages can be transmitted for each pair of remote UE and UE-to-NW relay UEs, considering the available paths between the two and the defined selection criteria.

[0096] As mentioned above, since multiple nthhop UE-to-NW relays may be receiving the discovery solicitation message from the 2ndhop UE-to-UE relay UE, each nthhop UE-to-NW relay UE may perform operations 407 and 408.

[0097] At operation 409.1 , the 2ndhop UE-to-UE relay UE determines whether to forward the discovery response message after receiving it at operation 408. In various embodiments, the 2ndhop UE-to-UE relay UE determines how to extend the multi-hop path selection procedure (e.g., which multi-hop UE-to-network relay discovery response message should be transmitted back to the previous hop (i.e., backward direction towards the remote UE). In case that two or more response messages have been received for the same initiator / remote UE or from the same UE-to- NW relay UE to reduce the number of transmitted messages by applying one or more of the following procedures: transmits only once the multi-hop UE-to-network relay discovery response message, e.g., the first time it has received a response message), waits for time Tr (i.e. from the moment that received the first discovery response message) to receive other multi-hop UE-to- network relay discovery response messages, before deciding which candidate relay UE IDs could be added in the response, retransmits a maximum number (Max Tx,) of discovery response messages, and / or according to defined transmission criteria (e.g., measured radio and / or congestion and / or QoS parameters, timing, etc.). In various embodiments, discovery response messages received from a number of hops larger than a threshold (e.g., N+l hops) are not forwarded.

[0098] At operation 410.1 , the 2ndhop UE-to-UE relay UE updates and transmits the updated discovery response message to one or more 1sthop UE-to-UE relay UEs. The discovery response message may be updated by, e.g., updating one or more selection information in the discovery response message. Various examples of selection information are described above. The 2ndhop UE-to-UE relay UE may transmit the updated discovery response message according to the list of IDs of the candidate relay UEs that have been discovered in the previous steps (i.e., during theprocess of transmission of discovery solicitation messages). The 2ndhop UE-to-UE relay UE may update the discovery response message with selection information including one or more of the following: candidate relay UE ID, measured radio link information (e.g., RSRP), congestion (e.g., CBR, CR) and QoS parameters (e.g., threshold data rate, packet loss, threshold delay) at the candidate relay UE, the location of candidate UE-to-UE relay UE, and mobility information of the candidate UE-to-UE relay UE.

[0099] As mentioned above, since multiple 2ndhop UE-to-UE relays may be receiving the discovery response message from the nthhop UE-to-NW relay UE, each 2ndhop UE-to-UE relay UE may perform operations 409.1 and 410.1.

[0100] At operation 409.2, in various embodiments the 1sthop UE-to-UE relay UE determines whether to forward the discovery response message after receiving it at operation 410.1. In various embodiments, the 1sthop UE-to-UE relay UE may utilize a similar determination as described above for the 2ndhop UE-to-UE relay UE at operation 409.1.

[0101] Accordingly, at operation 410.2, the 1sthop UE-to-UE relay UE updates and transmits the updated discovery response message to the remote UE and the remote UE receives the updated discovery response message. In various embodiments, the 1sthop UE-to-UE relay UE may update and transmit the discovery response message as described above for the 2ndhop UE-to-UE relay UE at operation 410.1.

[0102] As mentioned above, since multiple 2ndhop UE-to-UE relays may be receiving the discovery response message from the nthhop UE-to-NW relay UE, each 2ndhop UE-to-UE relay UE may perform operations 409.1 and 410.1.

[0103] As mentioned above, since multiple 1sthop UE-to-UE relays may be receiving the discovery response message from the 2ndhop UE-to-NW relay UE, each 1sthop UE-to-UE relay UE may perform operations 409.2 and 410.2.

[0104] At operation 411, the remote UE selects a multi-hop path for effecting multi-hop communications. In various embodiments, the remote UE may determine the multi-hop path based on the criteria received in the updated discovery response message received from the 1sthop UE- to-UE relay.

[0105] In various embodiments, the remote UE may select a multi-hop path on expiration of the waiting timer (Tm) or due to other triggered criteria (e.g., number of received discovery response messages, quality of received discovery response messages in terms of radio / QoS1 parameters) and / or select the multi-hop path based on one or more of the following selection information: the received information (e.g., end to end information, the time it took for the discovery response message to reach the remote UE, the number of hops the discovery response message has traveled to reach the remote UE, next-hop information, etc.), and / or the type of the multi-hop relay.

[0106] At operation 412, the remote UE establishes the multi-hop path by establishing the first hop (i.e., 1sthop UE-to-UE relay UE), according to the selected multi-hop relay UE-to-network relay UE.

[0107] Accordingly, FIG. 4 describes signal and operations involving various UEs, including a remote UE, a UE-to-UE relay UE, and a UE-to-NW relay UE. The following will describe operations from the perspective each of the UEs.

[0108] The following describes operations from the perspective of the remote UE. From such a perspective, a method may include receiving, by a first user equipment (UE), a first message from a second UE, the first message includes an indication of a request for multi-hop relaying, and first criteria for communicating via multi-hop relaying. The performance information of the first UE is determined. A determination is performed to transmit the first message to a third UE, the determining based on the performance information of the first UE and based on the first criteria being satisfied. A determination is performed that at least one criterion of the first criteria should be updated. At least one criterion is generated of a second criteria based on the performance information of the first UE and the first message, the first message is updated with the at least one criterion of the second criteria and the performance information of the first UE, and the first message is transmitted, after the updating of the first message, to the third UE, by the first UE. The first UE receives, from the third UE, a second message comprising information relating to a multihop relay to be established, the information relating to the multi-hop relay to be established including performance information for the third UE, and first selection information relating to the multi-hop relay to be established. The second message is updated by updating the first selection information with second selection information, and the first UE transmits to the second UE, the second message after the updating of the second message, the transmitting based on the performance information for the third UE and based on the first selection information being satisfied.

[0109] The following describes operations from the perspective of the UE-to-UE relay UE. From such a perspective, a method may include transmitting, by a first user equipment (UE), to a second UE, a first message including an indication of a request for multi-hop relaying, and first criteria for communicating via multi-hop relaying. The first UE receives, from the second UE, a second message comprising information relating to a multi-hop relay to be established, the second message comprising selection information relating to the multi-hop relay to be established, and transmits to the second UE, a third message, the transmitting of the third message based on the selection information relating to the multi-hop relay to be established satisfying the first criteria.

[0110] The following describes operations from the perspective of the UE-to-NW relay UE. From such a perspective, a method may include receiving, by a first user equipment (UE), from a second UE, a first message comprising first criteria for communicating via multi-hop relaying, and transmitting, by the first UE, to the second UE, a second message comprising selection information relating to a multi-hop relay to be established, the transmitting based on the first criteria being satisfied.

[0111] The signals and operations of FIG. 4 are merely illustrative, and variations are contemplated to be within the scope of the present disclosure. In embodiments, the signals and operations may include others not illustrated in FIG. 4. In embodiments, the signals and operations may not include every signal and operation illustrated in FIG. 4. In embodiments, the signals and operations may be implemented in a different order than that illustrated in FIG. 4. Such and other embodiments are contemplated to be within the scope of the present disclosure.

[0112] Referring now to FIG. 5, there is shown a block diagram of example components of a UE, connected device, or a network apparatus (e.g., of a RAN or a core network). The apparatus includes an electronic storage 510, a processor 520, a network interface 540, and a memory 550. The various components may be communicatively coupled with each other. The processor 520 may be and may include any type of processor, such as a single-core central processing unit (CPU), a multi-core CPU, a microprocessor, a digital signal processor (DSP), a System-on-Chip (SoC), or any other type of processor. The memory 550 may be a volatile type of memory, e.g., RAM, or a non-volatile type of memory, e.g., NAND flash memory. The memory 550 includes processor- readable instructions that are executable by the processor 520 to cause the apparatus to perform various operations, including those mentioned herein, such as the operations shown and described in connection with FIGS. 3-4.

[0113] The electronic storage 510 may be and include any type of electronic storage used for storing data, such as hard disk drive, solid state drive, and / or optical disc, among other types of electronic storage. The electronic storage 510 stores processor-readable instructions for causing the apparatus to perform its operations and stores data associated with such operations, such as storing data relating to 5G NR standards, among other data. The network interface 540 may implement wireless networking technologies such as 5G NR and / or other wireless networking technologies.

[0114] The components shown in FIG. 5 are merely examples, and persons skilled in the art will understand that an apparatus includes other components not illustrated and may include multiples of any of the illustrated components. Such and other embodiments are contemplated to be within the scope of the present disclosure.

[0115] Further embodiments of the present disclosure include the following examples.

[0116] Example 1.1. A user equipment (UE), comprising: means for receiving, by a first user equipment (UE), a first message from a second UE, the first message comprising: an indication of a request for multi-hop relaying, and first criteria for communicating via multi-hop relaying; means for determining performance information of the first UE; means for determining to transmit the first message to a third UE, the determining based on the performance information of the first UE and based on the first criteria being satisfied; means for determining that at least one criterion of the first criteria should be updated, and: means for generating at least one criterion of a second criteria based on the performance information of the first UE and the first message; means for updating the first message with the at least one criterion of the second criteria and the performance information of the first UE; and means for transmitting the first message, after the updating of the first message, to the third UE, by the first UE; means for receiving, by the first UE, from the third UE, a second message comprising information relating to a multi-hop relay to be established, the information relating to the multihop relay to be established comprising: performance information for the third UE, andfirst selection information relating to the multi-hop relay to be established; means for updating the second message by updating the first selection information with second selection information; and means for transmitting, by the first UE, to the second UE, the second message after the updating of the second message, the transmitting based on the performance information for the third UE and based on the first selection information being satisfied.

[0117] Example 1.2. The UE of example 1.1, wherein the first criteria comprise at least one criterion for extending or not extending the request for multi-hop relaying.

[0118] Example 1.3. The UE of example 1.2, wherein the first criteria comprise one or more of the following: radio link condition parameters, congestion parameters, quality of service (QoS) parameters, a maximum number of hops to a target device, a maximum duration of discovery procedure for multi-hop relaying, or a mobility profile of one or more candidate relay UEs.

[0119] Example 1.4. The UE of example 1.3, wherein the radio link condition parameters comprise a threshold of a measured sidelink discovery reference signal received power (SD- RSRP).

[0120] Example 1.5. The UE of example 1.3, wherein the congestion parameters comprise a threshold of a measured channel busy ration (CBR) value.

[0121] Example 1.6. The UE of example 1.3, wherein the QoS parameters comprise one or more of the following: threshold of data rate, threshold of delay, or packet loss.

[0122] Example 1.7. The UE of example 1.3, wherein the mobility profile of one or more candidate relay UEs comprises one or more of the following: a speed threshold of the one or more candidate relay UEs, a direction of the one or more candidate relay UEs, or a destination of the one or more candidate relay UEs.

[0123] Example 1.8. The UE of example 1.1, wherein the performance information of the first UE comprises parameters for communicating via multi-hop relaying.

[0124] Example 1.9. The UE of example 1.8, wherein the second criteria comprise any one of the following: a location information of the first UE, timing information of the first UE, or mobility information of the first UE.

[0125] Example 1.10. The UE of example 1.8, wherein the second criteria comprise any one of the following: measured radio link parameters, congestion parameters, mobility profile ofthe first UE, or QoS parameters at the first UE.

[0126] Example 1.11. The UE as in any one of examples 1.8-1.10, wherein the second criteria comprise an estimated QoS of the multi-hop path up to the first UE.

[0127] Example, 1.12. The UE of example 1.1, further comprising: means for receiving, by the first UE, one or more other messages distinct from the first message, wherein each message of the one or more other messages comprises an indication of a request for multi-hop relaying.

[0128] Example 1.13. The UE of example 1.12, further comprising: means for waiting, by the first UE, a predefined time for the receiving the one or more other messages; and means for determining which among the first message and the one or more other message is to be transmitted to the third UE.

[0129] Example 1.14. The UE of example 1.1, wherein the first UE transmits the second message to the second UE based on the third criteria satisfying the first criteria.

[0130] Example 1.15. The UE of example 1.1, further comprising: means for receiving, by the first UE, one or more other messages distinct from the second message, wherein each message of the one or more other messages comprises information relating to a multi-hop relay to be established.

[0131] Example 1.16. The UE of example 1.15, further comprising: means for waiting, by the first UE, a predefined time for the receiving the one or more other messages; and

[0132] determining which among the second message and the one or more other messages is to be transmitted to the second UE.

[0133] Example 1.17. The UE of example 1.1, wherein the first selection information comprises the third criteria.

[0134] Example 1.18. The UE of example 1.17, wherein the first selection information comprises one or more of the following: an identifier of a candidate relay UE, measured radio link condition parameters, congestion parameters, QoS parameters at the candidate relay UE, a location of the candidate relay UE, or mobility information of the first UE.

[0135] Example 2.1. A method comprising: transmitting, by a first user equipment (UE), to a second UE, a first message comprising: an indication of a request for multi-hop relaying, and first criteria for communicating via multi-hop relaying; receiving, by the first UE, from the second UE, a second message comprising information relating to a multi-hop relay to be established, the second message comprising selection information relating to the multi-hop relay to be established; and transmitting, by the first UE, to the second UE, a third message, the transmitting of the third message based on the selection information relating to the multi-hop relay to be established satisfying the first criteria.

[0136] Example 2.2. The method of example 2.1, wherein the first criteria comprise at least one criterion for extending or not extending the request for multi-hop relaying.

[0137] Example 2.3. The method of example 2.2, wherein the first criteria comprise one or more of the following: radio link condition parameters, congestion parameters, quality of service (QoS) parameters, a maximum number of hops to a target device, a maximum duration of discovery time for multi-hop relaying, or a mobility profile of one or more candidate relay UEs.

[0138] Example 2.4. The method of example 2.3, wherein the radio link condition parameters comprise a threshold of a measured sidelink discovery reference signal received power (SD-RSRP).

[0139] Example 2.5. The method of example 2.3, wherein the congestion parameters comprise a threshold of a measured channel busy ration (CBR) value.

[0140] Example 2.6. The method of example 2.3, wherein the QoS parameters comprise one or more of the following: threshold of data rate, threshold of delay, or packet loss.

[0141] Example 2.7. The method of example 2.3, wherein the mobility profile of one or more candidate relay UEs comprise a speed threshold of the one or more candidate relay UEs, a direction of the one or more candidate relay UEs, or a destination of the one or more candidate relay UEs.

[0142] Example 2.8. The method of example 2.1, wherein the selection information comprises one or more of the following: an identifier of a candidate relay UE, measured radio link condition parameters, congestion parameters, QoS parameters at the candidate relay UE, alocation of the candidate relay UE, or a mobility information of the first UE.

[0143] Example 2.9. The method of example 2.1, further comprising selecting, by the first UE, a multi-hop path for the multi-hop relay to be established.

[0144] Example 2.10. The method of example 2.1, further comprising waiting, by the firstUE, a predefined time for receiving the second message before transmitting the third message to the second UE.

[0145] Example 3.1. A method, comprising: receiving, by a first user equipment (UE), from a second UE, a first message comprising first criteria for communicating via multi-hop relaying; and transmitting, by the first UE, to the second UE, a second message comprising selection information relating to a multi-hop relay to be established, the transmitting based on the first criteria being satisfied.

[0146] Example 3.2. The method of example 3.1, wherein the first criteria comprise at least one criterion for extending or not extending the request for multi-hop relaying.

[0147] Example 3.3. The method of example 3.2, wherein the first criteria comprise one or more of the following: radio link condition parameters, congestion parameters, quality of service (QoS) parameters, a maximum number of hops to a target device, a maximum duration of discovery time for multi-hop relaying, or a mobility profile of one or more candidate relay UEs.

[0148] Example 3.4. The method of example 3.3, wherein the radio link condition parameters comprise a threshold of a measured sidelink discovery reference signal received power (SD-RSRP).

[0149] Example 3.5. The method of example 3.3, wherein the congestion parameters comprise a threshold of a measured channel busy ration (CBR) value.

[0150] Example 3.6. The method of example 3.3, wherein the QoS parameters comprise one or more of the following: threshold of data rate, threshold of delay, or packet loss.

[0151] Example 3.7. The method of example 3.3, wherein the mobility profile of one or more candidate relay UEs comprise a speed threshold of the one or more candidate relay UEs, a direction of the one or more candidate relay UEs, or a destination of the one or more candidate relay UEs.

[0152] Example 3.8. The method of example 3.1, wherein the selection information comprise one or more of the following: identifiers of candidate relay UEs, locations of the candidate relay UEs, a total time of discovery procedure, or mobility information of the first UE.

[0153] The embodiments and aspects disclosed herein are examples of the present disclosure and may be embodied in various forms. For instance, although certain embodiments herein are described as separate embodiments, each of the embodiments herein may be combined with one or more of the other embodiments herein. Specific structural and functional details disclosed herein are not to be interpreted as limiting, but as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present disclosure in virtually any appropriately detailed structure. Like reference numerals may refer to similar or identical elements throughout the description of the figures.

[0154] The phrases “in an aspect,” “in aspects,” “in various aspects,” “in some aspects,” or “in other aspects” may each refer to one or more of the same or different aspects in accordance with this present disclosure. The phrase “a plurality of’ may refer to two or more.

[0155] The phrases “in an embodiment,” “in embodiments,” “in various embodiments,” “in some embodiments,” or “in other embodiments” may each refer to one or more of the same or different embodiments in accordance with the present disclosure. A phrase in the form “A or B” means “(A), (B), or (A and B).” A phrase in the form “at least one of A, B, or C” means “(A); (B); (C); (A and B); (A and C); (B and C); or (A, B, and C) ”

[0156] Any of the herein described methods, programs, algorithms or codes may be converted to, or expressed in, a programming language or computer program. The terms “programming language” and “computer program,” as used herein, each include any language used to specify instructions to a computer, and include (but is not limited to) the following languages and their derivatives: Assembler, Basic, Batch files, BCPL, C, C+, C++, Delphi, Fortran, Java, JavaScript, machine code, operating system command languages, Pascal, Perl, PL1, Python, scripting languages, Visual Basic, metalanguages which themselves specify programs, and all first, second, third, fourth, fifth, or further generation computer languages. Also included are database and other data schemas, and any other meta-languages. No distinction is made between languages which are interpreted, compiled, or use both compiled and interpreted approaches. No distinction is made between compiled and source versions of a program. Thus, reference to a program, where the programming language could exist in more than one state (such as source, compiled, object, orlinked) is a reference to any and all such states. Reference to a program may encompass the actual instructions and / or the intent of those instructions.

[0157] While aspects of the present disclosure have been shown in the drawings, it is not intended that the present disclosure be limited thereto, as it is intended that the present disclosure be as broad in scope as the art will allow and that the specification be read likewise. Therefore, the above description should not be construed as limiting, but merely as exemplifications of particular aspects. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.

Claims

WHAT IS CLAIMED IS:

1. A method comprising: receiving, by a first user equipment (UE), a first message from a second UE, the first message comprising: an indication of a request for multi-hop relaying, and first criteria for communicating via multi-hop relaying, wherein the first criteria comprise at least one criterion for extending or not extending the request for multi-hop relaying, wherein the at least one criterion comprise one or more of the following: radio link condition parameters, congestion parameters, quality of service (QoS) parameters, a maximum duration of discovery procedure for multi-hop relaying, or a mobility profile of one or more candidate relay UEs; determining performance information of the first UE; determining to transmit the first message to a third UE, the determining based on the performance information of the first UE and based on the first criteria being satisfied; determining that at least one criterion of the first criteria should be updated, and: generating at least one criterion of a second criteria based on the performance information of the first UE and the first message; updating the first message with the at least one criterion of the second criteria and the performance information of the first UE; and transmitting the first message, after the updating of the first message, to the third UE, by the first UE; receiving, by the first UE, from the third UE, a second message comprising information relating to a multi-hop relay to be established, the information relating to the multi-hop relay to be established comprising: performance information for the third UE, and first selection information relating to the multi-hop relay to be established; updating the second message by updating the first selection information with second selection information; andtransmitting, by the first UE, to the second UE, the second message after the updating of the second message, the transmitting based on the performance information for the third UE and based on the first selection information being satisfied.

2. The method according to claim 1, wherein the radio link condition parameters comprise a threshold of a measured sidelink discovery reference signal received power (SD-RSRP).

3. The method according to claim 1, wherein the congestion parameters comprise a threshold of a measured channel busy ration (CBR) value.

4. The method according to claim 1, wherein the QoS parameters comprise one or more of the following: threshold of data rate, threshold of delay, or packet loss.

5. The method according to claim 1, wherein the mobility profile of one or more candidate relay UEs comprises one or more of the following: a speed threshold of the one or more candidate relay UEs, a direction of the one or more candidate relay UEs, or a destination of the one or more candidate relay UEs.

6. The method according to claim 1, wherein the performance information of the first UE comprises parameters for communicating via multi-hop relaying.

7. The method according to claim 6, wherein the second criteria comprise any one of the following: a location information of the first UE, timing information of the first UE, or mobility information of the first UE.

8. The method according to claim 6, wherein the second criteria comprise any one of the following: measured radio link parameters, congestion parameters, mobility profile of the first UE, or QoS parameters at the first UE.

9. The method according to any one of claims 6 to 8, wherein the second criteria comprise an estimated QoS of the multi-hop path up to the first UE.

10. The method according to claim 1, further comprising: receiving, by the first UE, one or more other messages distinct from the first message, wherein each message of the one or more other messages comprises an indication of a request for multi-hop relaying.

11. The method according to claim 10, further comprising: waiting, by the first UE, a predefined time for the receiving the one or more other messages; and determining which among the first message and the one or more other message is to be transmitted to the third UE.

12. The method according to claim 1 , wherein the first UE transmits the second message to the second UE based on the third criteria satisfying the first criteria.

13. The method according to claim 1, further comprising: receiving, by the first UE, one or more other messages distinct from the second message, wherein each message of the one or more other messages comprises information relating to a multi-hop relay to be established.

14. The method according to claim 13, further comprising: waiting, by the first UE, a predefined time for the receiving the one or more other messages; and determining which among the second message and the one or more other messages is to be transmitted to the second UE.

15. The method according to claim 1, wherein the first selection information comprises the third criteria.

16. The method according to claim 15, wherein the first selection information comprises one or more of the following: an identifier of a candidate relay UE, measured radio link conditionparameters, congestion parameters, QoS parameters at the candidate relay UE, a location of the candidate relay UE, or mobility information of the first UE.

17. A user equipment (UE, comprising: at least one processor; and at least one memory storing instructions which, when executed by the at least one processor, cause the user equipment at least to perform a method according to any one of claims 1 to 16.

18. A processor-readable medium storing instructions which, when executed by at least one processor of an apparatus, cause the apparatus at least to perform a method according to any one of claims 1 to 16.

19. A computer program comprising instructions which, when executed by an apparatus, cause the apparatus at least to perform a method according to any one of claims 1 to 16.

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