Proximity services with layer-3 multi-hop relays

Abstract

Systems and methods are disclosed for enabling Proximity Services (ProSe) with Layer- 3 multi-hop relays in a Mobile Ad-hoc Network (MANET). The apparatus includes a user equipment (UE) configured to act as a relay, collecting and advertising the list of reachable UEs. The method involves a discovery procedure where the relay gains awareness of nearby UEs and propagates this information using a Discovery Info message. The Discovery Info message includes the identities of reachable UEs, the relay's identity, and optional security information. The method also supports multi-hop UE-to-UE and UE-to-network relays, allowing for the establishment of communication paths through multiple relays.

Description

PROXIMITY SERVICES WITH LAYER-3 MULTI-HOP RELAYSPRIORITY CLAIM

[0001] This application claims the benefit of priority to United States Provisional Patent Application Serial No. 63 / 554,070, filed February 15, 2024, and United States Provisional Patent Application Serial No. 63 / 676,788, filed luly 29, 2024, each of which is incorporated herein by reference in its entirety.TECHNICAL FIELD

[0002] Embodiments pertain to wireless networks and wireless communications. Some embodiments relate to a multi-hop user equipment (UE)-to-UE Relay and multi-hop UE-to-Network Relay in a Proximity Service (ProSe) environment.BACKGROUND

[0003] Mobile communication has evolved significantly from early voice systems to highly sophisticated integrated communication platform. Nextgeneration (NG) wireless communication systems, including 5thgeneration (5G) and sixth generation (6G) or new radio (NR) systems, are to provide access to information and sharing of data by various users (e.g., user equipment (UEs)) and applications. NR is to be a unified network / system that is to meet vastly different and sometimes conflicting performance dimensions and services driven by different services and applications. As such, the complexity of such communication systems, as well as interactions between elements within a communication system, has increased. For example, the complexity of ProSe communications increases substantially when direct Layer-3 UE-UE communications are unavailable, that is, when more ProSe communications include multiple Layer-3 hops.BRIEF DESCRIPTION OF THE DRAWINGS

[0004] The present disclosure is illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like references indicate similar elements and in which:

[0005] FIG. 1 A illustrates an architecture of a network, in accordance with some aspects.

[0006] FIG. IB illustrates a non-roaming 5G system architecture in accordance with some aspects.

[0007] FIG. 1C illustrates a non-roaming 5G system architecture in accordance with some aspects.

[0008] FIG. 2 illustrates a block diagram of a communication device in accordance with some embodiments.

[0009] FIG. 3 illustrates Layer-3 multi-hop U2U Relay support in accordance with some embodiments.

[0010] FIG. 4 illustrates a ProSe UE-to-UE (U2U) Relay in accordance with some embodiments.

[0011] FIG. 5 illustrates ProSe U2U Relay Discovery in accordance with some embodiments.

[0012] FIG. 6 illustrates Layer-2 link establishment via 5G ProSe Layer- 3 UE-to-UE Relay in accordance with some embodiments.

[0013] FIG. 7 illustrates a Mobile Ad-hoc Network (MANET) network in accordance with some embodiments.

[0014] FIG. 8 illustrates MANET routers with ProSe U2U Relay functionality in accordance with some embodiments.

[0015] FIG. 9 illustrates signaling for connection establishment using the MANET routers of FIG. 8 in accordance with some embodiments.DESCRIPTION

[0016] The following description and the drawings sufficiently illustrate specific embodiments to enable those skilled in the art to practice them. Other embodiments may incorporate structural, logical, electrical, process, and other changes. Portions and features of some embodiments may be included in orsubstituted for, those of other embodiments. Embodiments outlined in the claims encompass all available equivalents of those claims.

[0017] FIG. 1 A illustrates an architecture of a network in accordance with some aspects. The network 140 A includes 3 GPP LTE / 4G and NG network functions that may be extended to 6G functions. Accordingly, although 5G will be referred to, it is to be understood that this is to extend as able to 6G structures, systems, and functions. A network function may be implemented as a discrete network element on a dedicated hardware, as a software instance running on dedicated hardware, and / or as a virtualized function instantiated on an appropriate platform, e.g., dedicated hardware or a cloud infrastructure.

[0018] The network 140 A is shown to include user equipment (UE) 101 and UE 102. The UEs 101 and 102 are illustrated as smartphones (e.g., handheld touchscreen mobile computing devices connectable to one or more cellular networks) but may also include any mobile or non-mobile computing device, such as portable (laptop) or desktop computers, wireless handsets, drones, or any other computing device including a wired and / or wireless communications interface. The UEs 101 and 102 may be collectively referred to herein as UE 101, and UE 101 may be used to perform one or more of the techniques disclosed herein.

[0019] Any of the radio links described herein (e.g., as used in the network 140 A or any other illustrated network) may operate according to any exemplary radio communication technology and / or standard. Any spectrum management scheme including, for example, dedicated licensed spectrum, unlicensed spectrum, (licensed) shared spectrum (such as Licensed Shared Access (LSA) in 2.3-2.4 GHz, 3.4-3.6 GHz, 3.6-3.8 GHz, and other frequencies and Spectrum Access System (SAS) in 3.55-3.7 GHz and other frequencies). Different Single Carrier or Orthogonal Frequency Domain Multiplexing (OFDM) modes (CP-OFDM, SC-FDMA, SC-OFDM, filter bank-based multicarrier (FBMC), OFDMA, etc.), and in particular 3 GPP NR, may be used by allocating the OFDM carrier data bit vectors to the corresponding symbol resources.

[0020] In some aspects, any of the UEs 101 and 102 can comprise an Internet-of-Things (loT) UE or a Cellular loT (CIoT) UE, which can comprise anetwork access layer designed for low-power loT applications utilizing shortlived UE connections. In some aspects, any of the UEs 101 and 102 can include a narrowband (NB) loT UE (e.g., such as an enhanced NB-IoT (eNB-IoT) UE and Further Enhanced (FeNB-IoT) UE). An loT UE can utilize technologies such as machine-to-machine (M2M) or machine-type communications (MTC) for exchanging data with an MTC server or device via a public land mobile network (PLMN), Proximity-Based Service (ProSe) or device-to-device (D2D) communication, sensor networks, or loT networks. The M2M or MTC exchange of data may be a machine-initiated exchange of data. An loT network includes interconnecting loT UEs, which may include uniquely identifiable embedded computing devices (within the Internet infrastructure), with short-lived connections. The loT UEs may execute background applications (e.g., keepalive messages, status updates, etc.) to facilitate the connections of the loT network. In some aspects, any of the UEs 101 and 102 can include enhanced MTC (eMTC) UEs or further enhanced MTC (FeMTC) UEs.

[0021] The UEs 101 and 102 may be configured to connect, e.g., communicatively couple, with a radio access network (RAN) 110. The RAN 110 may be, for example, an Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN), a NextGen RAN (NG RAN), or some other type of RAN.

[0022] The UEs 101 and 102 utilize connections 103 and 104, respectively, each of which comprises a physical communications interface or layer (discussed in further detail below); in this example, the connections 103 and 104 are illustrated as an air interface to enable communicative coupling, and may be consistent with cellular communications protocols, such as a Global System for Mobile Communications (GSM) protocol, a code-division multiple access (CDMA) network protocol, a Push-to-Talk (PTT) protocol, a PTT over Cellular (POC) protocol, a Universal Mobile Telecommunications System (UMTS) protocol, a 3GPP Long Term Evolution (LTE) protocol, a 5G protocol, a 6G protocol, and the like.

[0023] In an aspect, the UEs 101 and 102 may further directly exchange communication data via a ProSe interface 105. The ProSe interface 105 may alternatively be referred to as a sidelink (SL) interface comprising one or morelogical channels, including but not limited to a Physical Sidelink Control Channel (PSCCH), a Physical Sidelink Shared Channel (PSSCH), a Physical Sidelink Discovery Channel (PSDCH), a Physical Sidelink Broadcast Channel (PSBCH), and a Physical Sidelink Feedback Channel (PSFCH).

[0024] The UE 102 is shown to be configured to access an access point (AP) 106 via connection 107. The connection 107 can comprise a local wireless connection, such as, for example, a connection consistent with any IEEE 802.11 protocol, according to which the AP 106 can comprise a wireless fidelity (WiFi®) router. In this example, the AP 106 is shown to be connected to the Internet without connecting to the core network of the wireless system (described in further detail below).

[0025] The RAN 110 can include one or more access nodes that enable the connections 103 and 104. These access nodes (ANs) may be referred to as base stations (BSs), NodeBs, evolved NodeBs (eNBs), Next Generation NodeBs (gNBs), RAN nodes, and the like, and can comprise ground stations (e.g., terrestrial access points) or satellite stations providing coverage within a geographic area (e.g., a cell). In some aspects, the communication nodes 111 and 112 may be transmission / reception points (TRPs). In instances when the communication nodes 111 and 112 are NodeBs (e.g., eNBs or gNBs), one or more TRPs can function within the communication cell of the NodeBs. The RAN 110 may include one or more RAN nodes for providing macrocells, e.g., macro RAN node 111, and one or more RAN nodes for providing femtocells or picocells (e.g., cells having smaller coverage areas, smaller user capacity, or higher bandwidth compared to macrocells), e.g., low power (LP) RAN node 112.

[0026] Any of the RAN nodes 111 and 112 can terminate the air interface protocol and may be the first point of contact for the UEs 101 and 102. In some aspects, any of the RAN nodes 111 and 112 can fulfill various logical functions for the RAN 110 including, but not limited to, radio network controller (RNC) functions such as radio bearer management, uplink and downlink dynamic radio resource management and data packet scheduling, and mobility management. In an example, any of the nodes 111 and / or 112 may be a gNB, an eNB, or another type of RAN node.

[0027] The RAN 110 is shown to be communicatively coupled to a core network (CN) 120 via an SI interface 113. In aspects, the CN 120 may be an evolved packet core (EPC) network, a NextGen Packet Core (NPC) network, or some other type of CN (e.g., as illustrated in reference to FIGS. 1B-1C). In this aspect, the SI interface 113 is split into two parts: the Sl-U interface 114, which carries traffic data between the RAN nodes 111 and 112 and the serving gateway (S-GW) 122, and the Sl-mobility management entity (MME) interface 115, which is a signaling interface between the RAN nodes 111 and 112 and MMEs121.

[0028] In this aspect, the CN 120 comprises the MMEs 121, the S-GW122, the Packet Data Network (PDN) Gateway (P-GW) 123, and a home subscriber server (HSS) 124. The MMEs 121 may be similar in function to the control plane of legacy Serving General Packet Radio Service (GPRS) Support Nodes (SGSN). The MMEs 121 may manage mobility aspects in access such as gateway selection and tracking area list management. The HSS 124 may comprise a database for network users, including subscription-related information to support the network entities' handling of communication sessions. The CN 120 may comprise one or several HSSs 124, depending on the number of mobile subscribers, on the capacity of the equipment, on the organization of the network, etc. For example, the HSS 124 can provide support for routing / roaming, authentication, authorization, naming / addressing resolution, location dependencies, etc.

[0029] The S-GW 122 may terminate the SI interface 113 towards the RAN 110, and routes data packets between the RAN 110 and the CN 120. In addition, the S-GW 122 may be a local mobility anchor point for inter-RAN node handovers and also may provide an anchor for inter-3GPP mobility. Other responsibilities of the S-GW 122 may include a lawful intercept, charging, and some policy enforcement.

[0030] The P-GW 123 may terminate an SGi interface toward a PDN. The P-GW 123 may route data packets between the CN 120 and external networks such as a network including the application server 184 (alternatively referred to as application function (AF)) via an Internet Protocol (IP) interface 125. The P-GW 123 can also communicate data to other external networks131 A, which can include the Internet, IP multimedia subsystem (IPS) network, and other networks. Generally, the application server 184 may be an element offering applications that use IP bearer resources with the core network (e.g., UMTS Packet Services (PS) domain, LTE PS data services, etc.). In this aspect, the P-GW 123 is shown to be communicatively coupled to an application server 184 via an IP interface 125. The application server 184 can also be configured to support one or more communication services (e.g., Voice-over-Internet Protocol (VoIP) sessions, PTT sessions, group communication sessions, social networking services, etc.) for the UEs 101 and 102 via the CN 120.

[0031] The P-GW 123 may further be a node for policy enforcement and charging data collection. Policy and Charging Rules Function (PCRF) 126 is the policy and charging control element of the CN 120. In a non-roaming scenario, in some aspects, there may be a single PCRF in the Home Public Land Mobile Network (HPLMN) associated with a UE's Internet Protocol Connectivity Access Network (IP-CAN) session. In a roaming scenario with a local breakout of traffic, there may be two PCRFs associated with a UE's IP-CAN session: a Home PCRF (H-PCRF) within an HPLMN and a Visited PCRF (V-PCRF) within a Visited Public Land Mobile Network (VPLMN). The PCRF 126 may be communicatively coupled to the application server 184 via the P-GW 123.

[0032] In some aspects, the communication network 140 A may be an loT network or a 5G or 6G network, including 5G new radio network using communications in the licensed (5G NR) and the unlicensed (5G NR-U) spectrum. One of the current enablers of loT is the narrowband-IoT (NB-IoT). Operation in the unlicensed spectrum may include dual connectivity (DC) operation and the standalone LTE system in the unlicensed spectrum, according to which LTE-based technology solely operates in unlicensed spectrum without the use of an “anchor” in the licensed spectrum, called MulteFire. Further enhanced operation of LTE systems in the licensed as well as unlicensed spectrum is expected in future releases and 5G systems. Such enhanced operations can include techniques for sidelink resource allocation and UE processing behaviors for NR sidelink V2X communications.

[0033] An NG system architecture (or 6G system architecture) can include the RAN 110 and a 5G core network (5GC) 120. The NG-RAN 110 caninclude a plurality of nodes, such as gNBs and NG-eNBs. The CN 120 (e.g., a 5G core network / 5GC) can include an access and mobility function (AMF) and / or a user plane function (UPF). The AMF and the UPF may be communicatively coupled to the gNBs and the NG-eNBs via NG interfaces. More specifically, in some aspects, the gNBs and the NG-eNBs may be connected to the AMF by NG-C interfaces, and to the UPF by NG-U interfaces. The gNBs and the NG-eNBs may be coupled to each other via Xn interfaces.

[0034] In some aspects, the NG system architecture can use reference points between various nodes. In some aspects, each of the gNBs and the NG- eNBs may be implemented as a base station, a mobile edge server, a small cell, a home eNB, and so forth. In some aspects, a gNB may be a primary node (MN) and NG-eNB may be a secondary node (SN) in a 5G architecture.

[0035] FIG. IB illustrates a non-roaming 5G system architecture in accordance with some aspects. In particular, FIG. IB illustrates a 5G system architecture 140B in a reference point representation, which may be extended to a 6G system architecture. More specifically, UE 102 may be in communication with RAN 110 as well as one or more other 5GC network entities. The 5G system architecture 140B includes a plurality of network functions (NFs), such as an AMF 132, session management function (SMF) 136, policy control function (PCF) 148, application function (AF) 150, UPF 134, network slice selection function (NSSF) 142, authentication server function (AUSF) 144, and unified data management (UDM) / home subscriber server (HSS) 146.

[0036] The UPF 134 can provide a connection to a data network (DN) 152, which can include, for example, operator services, Internet access, or third- party services. The AMF 132 may be used to manage access control and mobility and can also include network slice selection functionality. The AMF 132 may provide UE-based authentication, authorization, mobility management, etc., and may be independent of the access technologies. The SMF 136 may be configured to set up and manage various sessions according to network policy. The SMF 136 may thus be responsible for session management and allocation of IP addresses to UEs. The SMF 136 may also select and control the UPF 134 for data transfer. The SMF 136 may be associated with a single session of a UE 101 or multiple sessions of the UE 101. This is to say that the UE 101 may havemultiple 5G sessions. Different SMFs may be allocated to each session. The use of different SMFs may permit each session to be individually managed. As a consequence, the functionalities of each session may be independent of each other.

[0037] The UPF 134 may be deployed in one or more configurations according to the desired service type and may be connected with a data network. The PCF 148 may be configured to provide a policy framework using network slicing, mobility management, and roaming (similar to PCRF in a 4G communication system). The UDM may be configured to store subscriber profiles and data (similar to an HSS in a 4G communication system).

[0038] The AF 150 may provide information on the packet flow to the PCF 148 responsible for policy control to support a desired QoS. The PCF 148 may set mobility and session management policies for the UE 101. To this end, the PCF 148 may use the packet flow information to determine the appropriate policies for proper operation of the AMF 132 and SMF 136. The AUSF 144 may store data for UE authentication.

[0039] In some aspects, the 5G system architecture 140B includes an IP multimedia subsystem (IMS) 168B as well as a plurality of IP multimedia core network subsystem entities, such as call session control functions (CSCFs). More specifically, the IMS 168B includes a CSCF, which can act as a proxy CSCF (P-CSCF) 162B, a serving CSCF (S-CSCF) 164B, an emergency CSCF (E-CSCF) (not illustrated in FIG. IB), or interrogating CSCF (I-CSCF) 166B. The P-CSCF 162B may be configured to be the first contact point for the UE 102 within the IM subsystem (IMS) 168B. The S-CSCF 164B may be configured to handle the session states in the network, and the E-CSCF may be configured to handle certain aspects of emergency sessions such as routing an emergency request to the correct emergency center or PSAP. The I-CSCF 166B may be configured to function as the contact point within an operator's network for all IMS connections destined to a subscriber of that network operator, or a roaming subscriber currently located within that network operator's service area. In some aspects, the I-CSCF 166B may be connected to another IP multimedia network 170B, e.g., an IMS operated by a different network operator.

[0040] In some aspects, the UDM / HSS 146 may be coupled to an application server 184, which can include a telephony application server (TAS) or another application server (AS) 160B. The AS 160B may be coupled to the IMS 168B via the S-CSCF 164B or the I-CSCF 166B.

[0041] A reference point representation shows that interaction can exist between corresponding NF services. For example, FIG. IB illustrates the following reference points: N1 (between the UE 102 and the AMF 132), N2 (between the RAN 110 and the AMF 132), N3 (between the RAN 110 and the UPF 134), N4 (between the SMF 136 and the UPF 134), N5 (between the PCF 148 and the AF 150, not shown), N6 (between the UPF 134 and the DN 152), N7 (between the SMF 136 and the PCF 148, not shown), N8 (between the UDM 146 and the AMF 132, not shown), N9 (between two UPFs 134, not shown), N10 (between the UDM 146 and the SMF 136, not shown), Ni l (between the AMF 132 and the SMF 136, not shown), N12 (between the AUSF 144 and the AMF 132, not shown), N13 (between the AUSF 144 and the UDM 146, not shown), N14 (between two AMFs 132, not shown), N15 (between the PCF 148 and the AMF 132 in case of a non-roaming scenario, or between the PCF 148 and a visited network and AMF 132 in case of a roaming scenario, not shown), N16 (between two SMFs, not shown), and N22 (between AMF 132 and NSSF 142, not shown). Other reference point representations not shown in FIG. IB can also be used.

[0042] FIG. 1C illustrates a 5G system architecture 140C and a servicebased representation. In addition to the network entities illustrated in FIG. IB, system architecture 140C can also include a network exposure function (NEF) 154 and a network repository function (NRF) 156. In some aspects, 5G system architectures may be service-based and interaction between network functions may be represented by corresponding point-to-point reference points Ni or as service-based interfaces.

[0043] In some aspects, as illustrated in FIG. 1C, service-based representations may be used to represent network functions within the control plane that enable other authorized network functions to access their services. In this regard, 5G system architecture 140C can include the following service-based interfaces: Namf 158H (a service-based interface exhibited by the AMF 132),Nsmf 1581 (a service-based interface exhibited by the SMF 136), Nnef 158B (a service-based interface exhibited by the NEF 154), Npcf 158D (a service-based interface exhibited by the PCF 148), a Nudm 158E (a service-based interface exhibited by the UDM 146), Naf 158F (a service-based interface exhibited by the AF 150), Nnrf 158C (a service-based interface exhibited by the NRF 156), Nnssf 158 A (a service-based interface exhibited by the NSSF 142), Nausf 158G (a service-based interface exhibited by the AUSF 144). Other service-based interfaces (e.g., Nudr, N5g-eir, and Nudsf) not shown in FIG. 1C can also be used.

[0044] NR-V2X architectures may support high-reliability low latency sidelink communications with a variety of traffic patterns, including periodic and aperiodic communications with random packet arrival time and size. Techniques disclosed herein may be used for supporting high reliability in distributed communication systems with dynamic topologies, including sidelink NR V2X communication systems.

[0045] FIG. 2 illustrates a block diagram of a communication device in accordance with some embodiments. The communication device 200 may be a UE such as a specialized computer, a personal or laptop computer (PC), a tablet PC, or a smart phone, dedicated network equipment such as an eNB, a server running software to configure the server to operate as a network device, a virtual device, or any machine capable of executing instructions (sequential or otherwise) that specify actions to be taken by that machine. For example, the communication device 200 may be implemented as one or more of the devices shown in FIGS. 1 A-1C. Note that communications described herein may be encoded before transmission by the transmitting entity (e.g., UE, gNB) for reception by the receiving entity (e.g., gNB, UE) and decoded after reception by the receiving entity.

[0046] Examples, as described herein, may include, or may operate on, logic or a number of components, modules, or mechanisms. Modules and components are tangible entities (e.g., hardware) capable of performing specified operations and may be configured or arranged in a certain manner. In an example, circuits may be arranged (e.g., internally or with respect to external entities such as other circuits) in a specified manner as a module. In an example,the whole or part of one or more computer systems (e.g., a standalone, client or server computer system) or one or more hardware processors may be configured by firmware or software (e.g., instructions, an application portion, or an application) as a module that operates to perform specified operations. In an example, the software may reside on a machine readable medium. In an example, the software, when executed by the underlying hardware of the module, causes the hardware to perform the specified operations.

[0047] Accordingly, the term “module” (and “component”) is understood to encompass a tangible entity, be that an entity that is physically constructed, specifically configured (e.g., hardwired), or temporarily (e.g., transitorily) configured (e.g., programmed) to operate in a specified manner or to perform part or all of any operation described herein. Considering examples in which modules are temporarily configured, each of the modules need not be instantiated at any one moment in time. For example, where the modules comprise a general -purpose hardware processor configured using software, the general -purpose hardware processor may be configured as respective different modules at different times. Software may accordingly configure a hardware processor, for example, to constitute a particular module at one instance of time and to constitute a different module at a different instance of time.

[0048] The communication device 200 may include a hardware processor (or equivalently processing circuitry) 202 (e.g., a central processing unit (CPU), a GPU, a hardware processor core, or any combination thereof), a main memory 204 and a static memory 206, some or all of which may communicate with each other via an interlink (e.g., bus) 208. The main memory 204 may contain any or all of removable storage and non-removable storage, volatile memory or non-volatile memory. The communication device 200 may further include a display unit 210 such as a video display, an alphanumeric input device 212 (e.g., a keyboard), and a user interface (UI) navigation device 214 (e.g., a mouse). In an example, the display unit 210, input device 212 and UI navigation device 214 may be a touch screen display. The communication device 200 may additionally include a storage device (e.g., drive unit) 216, a signal generation device 218 (e.g., a speaker), a network interface device 220, and one or more sensors, such as a global positioning system (GPS) sensor,compass, accelerometer, or another sensor. The communication device 200 may further include an output controller, such as a serial (e.g., universal serial bus (USB), parallel, or other wired or wireless (e.g., infrared (IR), near field communication (NFC), etc.) connection to communicate or control one or more peripheral devices (e.g., a printer, card reader, etc.).

[0049] The storage device 216 may include a non-transitory machine readable medium 222 (hereinafter simply referred to as machine readable medium) on which is stored one or more sets of data structures or instructions 224 (e.g., software) embodying or utilized by any one or more of the techniques or functions described herein. The non-transitory machine readable medium 222 is a tangible medium. The instructions 224 may also reside, completely or at least partially, within the main memory 204, within static memory 206, and / or within the hardware processor 202 during execution thereof by the communication device 200. While the machine readable medium 222 is illustrated as a single medium, the term "machine readable medium" may include a single medium or multiple media (e.g., a centralized or distributed database, and / or associated caches and servers) configured to store the one or more instructions 224.

[0050] The term “machine readable medium” may include any medium that is capable of storing, encoding, or carrying instructions for execution by the communication device 200 and that cause the communication device 200 to perform any one or more of the techniques of the present disclosure, or that is capable of storing, encoding or carrying data structures used by or associated with such instructions. Non-limiting machine-readable medium examples may include solid-state memories, and optical and magnetic media. Specific examples of machine-readable media may include non-volatile memory, such as semiconductor memory devices (e.g., Electrically Programmable Read-Only Memory (EPROM), Electrically Erasable Programmable Read-Only Memory (EEPROM)) and flash memory devices; magnetic disks, such as internal hard disks and removable disks; magneto-optical disks; Random Access Memory (RAM); and CD-ROM and DVD-ROM disks.

[0051] The instructions 224 may further be transmitted or received over a communications network using a transmission medium 226 via the networkinterface device 220 utilizing any one of a number of wireless local area network (WLAN) transfer protocols (e.g., frame relay, internet protocol (IP), transmission control protocol (TCP), user datagram protocol (UDP), hypertext transfer protocol (HTTP), etc.). Example communication networks may include a local area network (LAN), a wide area network (WAN), a packet data network (e.g., the Internet), mobile telephone networks (e.g., cellular networks), Plain Old Telephone (POTS) networks, and wireless data networks. Communications over the networks may include one or more different protocols, such as Institute of Electrical and Electronics Engineers (IEEE) 802.11 family of standards known as Wi-Fi, IEEE 802.16 family of standards known as WiMax, IEEE 802.15.4 family of standards, a Long Term Evolution (LTE) family of standards, a Universal Mobile Telecommunications System (UMTS) family of standards, peer-to-peer (P2P) networks, a next generation (NG) / 5thgeneration (5G) standards among others. In an example, the network interface device 220 may include one or more physical jacks (e.g., Ethernet, coaxial, or phonejacks) or one or more antennas to connect to the transmission medium 226.

[0052] Note that the term “circuitry” as used herein refers to, is part of, or includes hardware components such as an electronic circuit, a logic circuit, a processor (shared, dedicated, or group) and / or memory (shared, dedicated, or group), an Application Specific Integrated Circuit (ASIC), a field-programmable device (FPD) (e.g., a field-programmable gate array (FPGA), a programmable logic device (PLD), a complex PLD (CPLD), a high-capacity PLD (HCPLD), a structured ASIC, or a programmable SoC), digital signal processors (DSPs), etc., that are configured to provide the described functionality. In some embodiments, the circuitry may execute one or more software or firmware programs to provide at least some of the described functionality. The term “circuitry” may also refer to a combination of one or more hardware elements (or a combination of circuits used in an electrical or electronic system) with the program code used to carry out the functionality of that program code. In these embodiments, the combination of hardware elements and program code may be referred to as a particular type of circuitry.

[0053] The term “processor circuitry” or “processor” as used herein thus refers to, is part of, or includes circuitry capable of sequentially andautomatically carrying out a sequence of arithmetic or logical operations, or recording, storing, and / or transferring digital data. The term “processor circuitry” or “processor” may refer to one or more application processors, one or more baseband processors, a physical central processing unit (CPU), a single- or multi-core processor, and / or any other device capable of executing or otherwise operating computer-executable instructions, such as program code, software modules, and / or functional processes.

[0054] Any of the radio links described herein may operate according to any one or more of the following radio communication technologies and / or standards including but not limited to: a Global System for Mobile Communications (GSM) radio communication technology, a General Packet Radio Service (GPRS) radio communication technology, an Enhanced Data Rates for GSM Evolution (EDGE) radio communication technology, and / or a Third Generation Partnership Project (3GPP) radio communication technology, for example Universal Mobile Telecommunications System (UMTS), Freedom of Multimedia Access (FOMA), 3GPP Long Term Evolution (LTE), 3GPP Long Term Evolution Advanced (LTE Advanced), Code division multiple access 2000 (CDMA2000), Cellular Digital Packet Data (CDPD), Mobitex, Third Generation (3G), Circuit Switched Data (CSD), High-Speed Circuit- Switched Data (HSCSD), Universal Mobile Telecommunications System (Third Generation) (UMTS (3 G)), Wideband Code Division Multiple Access (Universal Mobile Telecommunications System) (W-CDMA (UMTS)), High Speed Packet Access (HSPA), High-Speed Downlink Packet Access (HSDPA), High-Speed Uplink Packet Access (HSUPA), High Speed Packet Access Plus (HSPA+), Universal Mobile Telecommunications System-Time-Division Duplex (UMTS-TDD), Time Division-Code Division Multiple Access (TD-CDMA), Time Division- Synchronous Code Division Multiple Access (TD-CDMA), 3rd Generation Partnership Project Release 8 (Pre-4th Generation) (3 GPP Rel. 8 (Pre-4G)), 3GPP Rel. 9 (3rd Generation Partnership Project Release 9), 3GPP Rel. 10 (3rd Generation Partnership Project Release 10) , 3GPP Rel. 11 (3rd Generation Partnership Project Release 11), 3GPP Rel. 12 (3rd Generation Partnership Project Release 12), 3GPP Rel. 13 (3rd Generation Partnership Project Release 13), 3GPP Rel. 14 (3rd Generation Partnership Project Release 14), 3GPP Rel.15 (3rd Generation Partnership Project Release 15), 3GPP Rel. 16 (3rd Generation Partnership Project Release 16), 3GPP Rel. 17 (3rd Generation Partnership Project Release 17) and subsequent Releases (such as Rel. 18, Rel. 19, etc ), 3GPP 5G, 5G, 5G New Radio (5G NR), 3GPP 5G New Radio, 3GPP LTE Extra, LTE- Advanced Pro, LTE Licensed-Assisted Access (LAA), MuLTEfire, UMTS Terrestrial Radio Access (UTRA), Evolved UMTS Terrestrial Radio Access (E-UTRA), Long Term Evolution Advanced (4th Generation) (LTE Advanced (4G)), cdmaOne (2G), Code division multiple access 2000 (Third generation) (CDMA2000 (3 G)), Evolution-Data Optimized or Evolution-Data Only (EV-DO), Advanced Mobile Phone System (1st Generation) (AMPS (1G)), Total Access Communication System / Extended Total Access Communication System (TACSZETACS), Digital AMPS (2nd Generation) (D-AMPS (2G)), Push-to-talk (PTT), Mobile Telephone System (MTS), Improved Mobile Telephone System (IMTS), Advanced Mobile Telephone System (AMTS), OLT (Norwegian for Offentlig Landmobil Telefoni, Public Land Mobile Telephony), MTD (Swedish abbreviation for Mobiltelefonisystem D, or Mobile telephony system D), Public Automated Land Mobile (Autotel / PALM), ARP (Finnish for Autoradiopuhelin, "car radio phone"), NMT (Nordic Mobile Telephony), High capacity version of NTT (Nippon Telegraph and Telephone) (Hicap), Cellular Digital Packet Data (CDPD), Mobitex, DataTAC, Integrated Digital Enhanced Network (iDEN), Personal Digital Cellular (PDC), Circuit Switched Data (CSD), Personal Handyphone System (PHS), Wideband Integrated Digital Enhanced Network (WiDEN), iBurst, Unlicensed Mobile Access (UMA), also referred to as 3GPP Generic Access Network, or GAN standard), Zigbee, Bluetooth(r), Wireless Gigabit Alliance (WiGig) standard, mmWave standards in general (wireless systems operating at 10-300 GHz and above such as WiGig, IEEE 802.1 lad, IEEE 802. Hay, etc.), technologies operating above 300 GHz and THz bands, (3GPP / LTE based or IEEE 802.1 Ip or IEEE 802.1 Ibd and other) Vehicle-to- Vehicle (V2V) and Vehicle-to-X (V2X) and Vehicle-to-Infrastructure (V2I) and Infrastructure-to-Vehicle (12 V) communication technologies, 3GPP cellular V2X, DSRC (Dedicated Short Range Communications) communication systems such as Intelligent-Transport-Systems and others (typically operating in 5850MHz to 5925 MHz or above (typically up to 5935 MHz following change proposals in CEPT Report 71)), the European ITS-G5 system (i.e. the European flavor of IEEE 802. l ip based DSRC, including ITS-G5 A (i.e., Operation of ITS-G5 in European ITS frequency bands dedicated to ITS for safety related applications in the frequency range 5,875 GHz to 5,905 GHz), ITS-G5B (i.e., Operation in European ITS frequency bands dedicated to ITS non-safety applications in the frequency range 5,855 GHz to 5,875 GHz), ITS-G5C (i.e., Operation of ITS applications in the frequency range 5,470 GHz to 5,725 GHz)), DSRC in Japan in the 700MHz band (including 715 MHz to 725 MHz), IEEE 802.1 Ibd based systems, etc.

[0055] Aspects described herein may be used in the context of any spectrum management scheme including dedicated licensed spectrum, unlicensed spectrum, license exempt spectrum, (licensed) shared spectrum (such as LSA = Licensed Shared Access in 2.3-2.4 GHz, 3.4-3.6 GHz, 3.6-3.8 GHz and further frequencies and SAS = Spectrum Access System / CBRS = Citizen Broadband Radio System in 3.55-3.7 GHz and further frequencies). Applicable spectrum bands include IMT (International Mobile Telecommunications) spectrum as well as other types of spectrum / bands, such as bands with national allocation (including 450 - 470 MHz, 902-928 MHz (note: allocated for example in US (FCC Part 15)), 863-868.6 MHz (note: allocated for example in European Union (ETSI EN 300 220)), 915.9-929.7 MHz (note: allocated for example in Japan), 917-923.5 MHz (note: allocated for example in South Korea), 755-779 MHz and 779-787 MHz (note: allocated for example in China), 790 - 960 MHz, 1710 - 2025 MHz, 2110 - 2200 MHz, 2300 - 2400 MHz, 2.4-2.4835 GHz (note: it is an ISM band with global availability and it is used by Wi-Fi technology family (1 Ib / g / n / ax) and also by Bluetooth), 2500 - 2690 MHz, 698-790 MHz, 610 - 790 MHz, 3400 - 3600 MHz, 3400 - 3800 MHz, 3800 - 4200 MHz, 3.55- 3.7 GHz (note: allocated for example in the US for Citizen Broadband Radio Service), 5.15-5.25 GHz and 5.25-5.35 GHz and 5.47-5.725 GHz and 5.725-5.85 GHz bands (note: allocated for example in the US (FCC part 15), consists four U-NII bands in total 500 MHz spectrum), 5.725-5.875 GHz (note: allocated for example in EU (ETSI EN 301 893)), 5.47-5.65 GHz (note: allocated for example in South Korea, 5925-7125 MHz and 5925-6425MHz band (note: underconsideration in US and EU, respectively. Next generation Wi-Fi system is expected to include the 6 GHz spectrum as operating band, but it is noted that, as of December 2017, Wi-Fi system is not yet allowed in this band. Regulation is expected to be finished in 2019-2020 time frame), IMT-advanced spectrum, IMT-2020 spectrum (expected to include 3600-3800 MHz, 3800 - 4200 MHz, 3.5 GHz bands, 700 MHz bands, bands within the 24.25-86 GHz range, etc.), spectrum made available under FCC's "Spectrum Frontier" 5G initiative (including 27.5 - 28.35 GHz, 29.1 - 29.25 GHz, 31 - 31.3 GHz, 37 - 38.6 GHz, 38.6 - 40 GHz, 42 - 42.5 GHz, 57 - 64 GHz, 71 - 76 GHz, 81 - 86 GHz and 92 - 94 GHz, etc.), the ITS (Intelligent Transport Systems) band of 5.9 GHz (typically 5.85-5.925 GHz) and 63-64 GHz, bands currently allocated to WiGig such as WiGig Band 1 (57.24-59.40 GHz), WiGig Band 2 (59.40-61.56 GHz) and WiGig Band 3 (61.56-63.72 GHz) and WiGig Band 4 (63.72-65.88 GHz), 57-64 / 66 GHz (note: this band has near-global designation for Multi-Gigabit Wireless Systems (MGWS) / WiGig . In US (FCC part 15) allocates total 14 GHz spectrum, while EU (ETSI EN 302 567 and ETSI EN 301 217-2 for fixed P2P) allocates total 9 GHz spectrum), the 70.2 GHz - 71 GHz band, any band between 65.88 GHz and 71 GHz, bands currently allocated to automotive radar applications such as 76-81 GHz, and future bands including 94-300 GHz and above. Furthermore, the scheme may be used on a secondary basis on bands such as the TV White Space bands (typically below 790 MHz) where in particular the 400 MHz and 700 MHz bands are promising candidates. Besides cellular applications, specific applications for vertical markets may be addressed such as PMSE (Program Making and Special Events), medical, health, surgery, automotive, low-latency, drones, etc. applications.

[0056] As above, enabling multi-hop Layer-3 ProSe communications may be complex; architecture enhancements may be used to support a ProSe multi-hop Layer-3 U2U Relay over a NR PC5 reference point that supports direct communications for both in coverage and out of coverage operation. In particular, aspects for a single hop ProSe U2U Relay such as support for relay discovery, selection, authorization, connection establishment, and data transfer may be enhanced to support multi -hop scenarios. While 3GPP TS 23.304 defines a Layer-2 ProSe U2U Relay and a Layer-3 U2U Relay, only the Layer-3U2U Relay is discussed herein. FIG. 3 illustrates Layer-3 multi-hop U2U Relay support in accordance with some embodiments. As shown in the general diagram of FIG. 3, two end UEs (which do not provide the functionality of U2U ProSe Relays within the MANET) are connected by a network of relays. FIG. 4 illustrates a ProSe UE-to-UE Relay in accordance with some embodiments. In FIG. 4, End UE A and End UE B are communicatively coupled by a U2U Relay. The End UEs (End UE A and End UE B) are out of each other’ s coverage, but each is within the coverage of the U2U Relay. The U2U Relay performs ProSe Discovery (see TS 23.304, clause 6.3.2.4.2) of other UEs in proximity and obtains the User Info ID of the discovered UEs (per the Relay Service Code (RSC)). RSC indicates the connectivity service that the ProSe U2U Relay provides to ProSe End UEs. The U2U Relay starts announcing the list of discovered User Info IDs (per RSC) using a U2U Relay Discovery Announcement message. FIG. 5 illustrates ProSe UE-to-UE Relay Discovery in accordance with some embodiments. FIG. 5 describes a Model A ProSe UE-to- UE Relay Discovery procedure in which:

[0057] 1. The 5G ProSe UE-to-UE Relay has discovered other UEs in proximity and obtains the Direct discovery set from other UEs in proximity per RSC (e.g., via a previous 5G ProSe UE-to-UE Relay Discovery or via secure PC5 connection between 5G ProSe U2U Relay and 5G ProSe End UE (refer to TS 33.503)).

[0058] 2. The 5G ProSe UE-to-UE Relay sends a UE-to-UE RelayDiscovery Announcement message. The UE-to-UE Relay Discovery Announcement message contains the Type of Discovery Message, User Info ID of the 5G ProSe UE-to-UE Relay, RSC and Direct discovery set including list of protected user info (i.e., Application Layer ID) received from the 5G ProSe End UEs supporting RSC. The UE-to-UE Relay Discovery Announcement message is sent using the Source Layer-2 ID and Destination Layer-2 ID as described in clause 5.8.4. The 5G ProSe UE-to-UE Relay shall only announce user info (i.e. Application Layer ID) of other UEs in proximity that did not include an Announce Prohibited Indication when they were previously discovered. The 5G ProSe UE-to-UE Relay announces Direct discovery set from other UEs in proximity only if their PC5 signal strength measured by the 5G ProSe UE-to-UERelay is above configured signal strength threshold as specified in TS 38.331. A 5G ProSe End UE monitors announcement messages from a 5G ProSe UE-to- UE Relay. The 5G ProSe End UEs determine the Destination Layer-2 ID for signaling reception as specified in TS 23.304 clause 5.1.

[0059] The U2U Relay discovery based on announcement messages as illustrated in FIG. 5 is referred to as ProSe Discovery Model A. For completeness, ProSe Discovery Model B based on a solicitation / response paradigm may instead be used, as indicated in TS 23.304 clause 6.3.2.4.3.

[0060] If End UE A wishes to establish a connection with End UE B, with which End UE A does not have a direct communication link, End UE A starts listening to the announcement messages of neighboring U2U Relays (Model A) or solicits potential neighboring relays for response (Model B). When End UE A determines that a neighboring U2U Relay is advertising the User Info of End UE B, End UE A initiates a Direct Communication procedure as described in TS 23.304 clause 6.7.1.1. FIG. 6 illustrates Layer-2 link establishment via 5G ProSe Layer-3 UE-to-UE Relay in accordance with some embodiments. FIG. 6 describes a Layer-2 link establishment in which:

[0061] 1. Service authorization and provisioning are performed for source 5G ProSe Layer-3 End UE, target 5G ProSe Layer-3 End UE and 5G ProSe Layer-3 UE-to-UE Relay as described in clause 6.2.

[0062] 2. The source 5G ProSe Layer-3 End UE performs discovery of a5G ProSe Layer-3 UE-to-UE Relay as described in clause 6.3.2.4.

[0063] 3. The source 5G ProSe Layer-3 End UE sends a DirectCommunication Request message to initiate the unicast Layer-2 link establishment procedure with the 5G ProSe Layer-3 UE-to-UE Relay. The parameters included in the Direct Communication Request message are described in clause 6.4.3.7.

[0064] The Source Layer-2 ID of the Direct Communication Request message is self-assigned by the source 5G ProSe Layer-3 End UE and the Destination Layer-2 ID is set to the Source Layer-2 ID of the discovery message of the 5G ProSe Layer-3 UE-to-UE Relay.

[0065] The source 5G ProSe Layer-3 End UE gets application information and optional ProSe Application Requirements from ProSeapplication layer, and determines the end-to-end QoS parameters as described in clause 5.6.3.1.

[0066] 4. If the User Info ID of 5G ProSe Layer-3 UE-to-UE Relay in the Direct Communication Request message matches the 5G ProSe UE-to-UE Relay's User Info ID and RSC in the Direct Communication Request matches one RSC that the relay is (pre)configured with, as specified in clause 5.1.5.1, the 5G ProSe Layer-3 UE-to-UE Relay responds by establishing the security with the source 5G ProSe Layer-3 End UE. When the security protection is enabled, the source 5G ProSe Layer-3 End UE sends the parameters as described in clause 6.4.3.7 to the 5G ProSe Layer-3 UE-to-UE Relay.

[0067] If the Ethernet MAC address of source 5G ProSe Layer-3 End UE is already used by another 5G ProSe Layer-3 End UE, then the 5G ProSe Layer- 3 UE-to-UE Relay rejects the direct link establishment indicating that the MAC address is not unique.

[0068] The Source Layer-2 ID used for the security establishment procedure is self-assigned by the 5G ProSe Layer-3 UE-to-UE Relay and the Destination Layer-2 ID is set to the Source Layer-2 ID of the received Direct Communication Request message.

[0069] The 5G ProSe Layer-3 UE-to-UE Relay shall choose different Source Layer-2 IDs for PC5 links of different types of traffic, i.e., IP traffic, Ethernet traffic and Unstructured traffic.

[0070] If the PC5 link is used for transferring Unstructured traffic, the5G ProSe Layer-3 UE-to-UE Relay shall choose different Source Layer-2 IDs for different pair of source and target 5G ProSe Layer-3 End UEs.

[0071] Upon receiving the security establishment procedure messages, the source 5G ProSe Layer-3 End UE obtains the 5G ProSe Layer-3 UE-to-UE Relay's Layer-2 ID for future communication, for signaling and data traffic for this unicast link.

[0072] 5. After the Security Establishment procedure in step 4 is completed, the 5G ProSe Layer-3 UE-to-UE Relay decides whether to use an existing unicast Layer-2 link between itself and the target 5G ProSe End UE for the required service. If there is no existing unicast Layer-2 link of the required RSC with the target 5G ProSe Layer-3 End UE, the 5G ProSe Layer-3 UE-to-UERelay sends a Direct Communication Request message to initiate the unicast Layer-2 link establishment procedure with the target 5G ProSe Layer-3 End UE. The parameters included in the Direct Communication Request message are described in clause 6.4.3.7.

[0073] The Source Layer-2 ID of the Direct Communication Request message is self-assigned by the 5G ProSe Layer-3 UE-to-UE Relay and the Destination Layer-2 ID may be broadcast or unicast Layer-2 ID. Unicast Layer-2 ID is used only if the Layer-2 ID of the target 5G ProSe Layer-3 End UE associated with the user info (i.e. Application Layer ID) is known to the 5G ProSe Layer-3 UE-to-UE Relay.

[0074] The 5G ProSe Layer-3 UE-to-UE Relay shall choose different Source Layer-2 IDs for PC5 links of different types of traffic, i.e., IP traffic, Ethernet traffic and Unstructured traffic.

[0075] If the PC5 link is used for transferring Unstructured traffic, the 5G ProSe Layer-3 UE-to-UE Relay shall choose different Source Layer-2 IDs for different pair of source and target 5G ProSe Layer-3 End UEs.

[0076] 6. If RSC included in the Direct Communication Request matches the target UE's RSC that the target UE is (pre)configured with as specified in clause 5.1.5.1 and if the user info included in the Direct Communication Request matches the target UE's user info, the target 5G ProSe Layer-3 End UE responds by establishing the security with the 5G ProSe Layer-3 UE-to-UE Relay. When the security protection is enabled, the 5G ProSe Layer-3 UE-to-UE Relay sends the parameters as described in clause 6.4.3.7 to the target 5G ProSe Layer-3 End UE.

[0077] The Source Layer-2 ID used for the security establishment procedure is self-assigned by the target 5G ProSe Layer-3 End UE and the Destination Layer-2 ID is set to the Source Layer-2 ID of the received Direct Communication Request message.

[0078] Upon receiving the security establishment procedure messages, the 5G ProSe Layer-3 UE-to-UE Relay obtains the target 5G ProSe Layer-3 End UE's Layer-2 ID for future communication, for signaling and data traffic for this unicast link.

[0079] 7. The target 5G ProSe Layer-3 End UE sends a DirectCommunication Accept message to the 5G ProSe Layer-3 UE-to-UE Relay that has successfully established security with. The parameters included in the Direct Communication Accept message are described in clause 6.4.3.7.

[0080] The 5G ProSe Layer-3 UE-to-UE Relay can detect that the Ethernet MAC address of target 5G ProSe Layer-3 End UE is already used by another 5G ProSe Layer-3 End UE when it receives the Direct Communication Accept message.

[0081] 8. For IP traffic, IPv6 prefix or IPv4 address is allocated for the target 5G ProSe Layer-3 End UE as defined in clause 5.5.1.4.

[0082] 9. After receiving the Direct Communication Accept message from the target 5G ProSe Layer-3 End UE, the 5G ProSe Layer-3 UE-to-UE Relay sends a Direct Communication Accept message to the source 5G ProSe Layer-3 End UE that has successfully established security with. The parameters included in the Direct Communication Accept message are described in clause 6.4.3.7.

[0083] 10. For IP traffic, IPv6 prefix or IPv4 address is allocated for the source 5G ProSe Layer-3 End UE as defined in clause 5.5.1.4.

[0084] 11. For IP communication, the 5G ProSe Layer-3 UE-to-UERelay may store an association of user info (i.e. Application Layer ID) and the IP address of target 5G ProSe Layer-3 End UE into its Domain Name System (DNS) entries and the 5G ProSe Layer-3 UE-to-UE Relay may act as a DNS server to other UEs. The source 5G ProSe Layer-3 End UE may send a DNS query to the 5G ProSe Layer-3 UE-to-UE Relay to request IP address of target 5G ProSe Layer-3 End UE after step 10 if the IP address of target 5G ProSe Layer-3 End UE is not received in step 9 and the 5G ProSe Layer-3 UE-to-UE Relay returns the IP address of the target 5G ProSe Layer-3 End UE to the source 5G ProSe Layer-3 End UE.

[0085] For Ethernet communication, the 5G ProSe Layer-3 UE-to-UE Relay maintains the association between PC5 links and Ethernet MAC addresses received from the 5G ProSe Layer-3 End UE.

[0086] For Unstructured traffic communication, for each pair of source and target 5G ProSe Layer-3 End UEs, the 5G ProSe Layer-3 UE-to-UE Relaymaintains the 1 : 1 mapping between the PC5 link with source 5G ProSe Layer-3 End UE and the PC5 link with target 5G ProSe Layer-3 End UE.

[0087] 12. The source 5G ProSe Layer-3 End UE communicates with the target 5G ProSe Layer-3 End UE via the 5G ProSe Layer-3 UE-to-UE Relay.

[0088] In the case of one source 5G ProSe Layer-3 End UE communicates with multiple target 5G ProSe Layer-3 End UEs, the PC5 link between the source 5G ProSe Layer-3 End UE and the 5G ProSe Layer-3 UE-to- UE Relay can be shared for multiple target 5G ProSe Layer-3 End UEs per RSC while the PC5 links may be established individually between the 5G ProSe Layer-3 UE-to-UE Relay and target 5G ProSe Layer-3 End UEs per RSC. For the shared PC5 link, the Layer-2 link modification procedure shall be used, replacing the step 3 to 4 and 9 to 10 of the procedure in Figure 6.7.1.1-1. The parameters used in the Layer-2 link modification procedure are described in clause 6.4.3.7.

[0089] In the case of multiple source 5G ProSe Layer-3 End UEs communicate with one target 5G ProSe Layer-3 End UE, the PC5 link between the 5G ProSe Layer-3 UE-to-UE Relay and the target 5G ProSe Layer-3 End UE can be shared per RSC while the PC5 links may be established individually between the source 5G ProSe Layer-3 End UEs and the 5G ProSe Layer-3 UE- to-UE Relay per RSC. For the shared PC5 link, the Layer-2 link modification procedure shall be used, replacing the step 5 to 8 of the procedure in Figure 6.7.1.1-1. The parameters used in the Layer-2 link modification procedure are described in clause 6.4.3.7.

[0090] The Direct Communication Request message over the first hop PC5 reference point includes: User Info ID of source 5G ProSe End UE: the identity of the source 5G ProSe End UE requesting relay operation; User Info ID of 5G ProSe UE-to-UE Relay: the identity of the UE-to-UE Relay provided to the source 5G ProSe End UE during 5G ProSe UE-to-UE Relay Discovery procedure; User Info ID of target 5G ProSe End UE: the identity of the target 5G ProSe End UE provided to the source 5G ProSe End UE during UE-to-UE Relay Discovery procedure; (optional) Destination Layer-2 ID of target 5G ProSe End UE: the unicast destination Layer-2 ID of the target 5G ProSe End UE determined by the source 5G ProSe End UE; ProSe Service Info: the informationabout the ProSe identifier(s) requesting Layer-2 link establishment; RSC: the connectivity service provided by the 5G ProSe UE-to-UE Relay as requested by the source 5G ProSe End LE; and Security Information: the information for the establishment of security for the first hop PC5 link establishment.

[0091] The Direct Communication Request message over the second hop PC5 reference point includes: User Info ID of source 5G ProSe End UE; User Info ID of target 5G ProSe End UE; User Info ID of 5G ProSe UE-to-UE Relay; ProSe Service Info: the information about the ProSe identified s); RSC: the connectivity service provided by the 5G ProSe UE-to-UE Relay as requested by the source 5G ProSe End UE; Security Information: the information for the establishment of security for the second hop PC 5 link establishment.

[0092] The Direct Communication Accept message over the second hop PC5 reference point includes the User Info ID of target 5G ProSe End UE.

[0093] The Direct Communication Accept message over the first hop PC5 reference point includes the User Info ID of target 5G ProSe End UE and the User Info ID of 5G ProSe UE-to-UE Relay.

[0094] Rel-18 specifications support only a single-hop U2U Relay. To support a Multi-hop U2U Relay, Multi-hop ProSe UE-to-UE Relays that have a collocated MANET router functionality that connect with neighboring MANET routers are used to establish a mobile ad hoc network as defined in MANET.The Multi-hop ProSe UE-to-UE Relay with collocated MANET router relies on a new MANET message to exchange information about discovered ProSe End UEs. ProSe UE-to-UE Relays also exchange point-to-point signaling messages (related to ProSe Direct Communication establishment and release) with each other over the MANET.

[0095] FIG. 7 illustrates a MANET network in accordance with some embodiments. FIG. 7 depicts a simple MANET network that includes five routers (A, B, C, D and E). The participating routers establish links with neighboring routers and perform the MANET Neighborhood Discovery Protocol (NHDP) by exchanging Hello messages with each adjacent MANET router as defined in IETF RFC 6130. The Hello messages are enhanced as defined in the MANET specification per IETF RFC 7181.

[0096] Based on the information exchanged in the Hello messages, the participating routers may select a set of “flooding multi-point relays” (flooding MPRs) and a set of “routing multi-point relays” (routing MPRs) to achieve flooding reduction and topology reduction, respectively. Only flooding MPRs forward control messages flooded through the MANET, thus effecting a flooding reduction, an optimization of the flooding mechanism, known as MPR flooding. Routing MPRs are used to provide a topology reduction in the MANET. If no such reduction is required, then a router can select all of its relevant neighbors as routing MPRs.

[0097] IETF RFC 7181 defines a second type of MANET message referred to as a Topology Control (TC) message that carries selected topology (link state) information. Contrary to the Hello messages that are exchanged locally between two adjacent MANET routers, the TC messages are diffused throughout the MANET, preferably by using MPR flooding.

[0098] FIG. 8 illustrates MANET routers with ProSe UE-to-UE Relay functionality in accordance with some embodiments. That is, FIG. 8 illustrates the diffusion of TC message generated by Router E using MPR flooding. In this example Router E has selected Router D and Router A, but not Router C, as MPRs. The MPR flooding is an optional feature. As above, the MANET network in FIG. 8 includes MANET routers that also have collocated ProSe UE- to-UE Relay functionality, as defined by 3GPP.

[0099] As illustrated in FIG. 8, every router except Router D is in proximity of a set of End UEs. By performing ProSe Discovery (Model A or Model B) as defined in TS 23.304, each of the U2U Relays discovers the UEs in proximity and obtains a list of locally discovered User Info IDs. Thus, as shown, U2U Relay A obtains a list of (User Info Al, User Info A2, User Info A3); U2U Relay B obtains a list of (User Info Bl, User Info B2); U2U Relay C obtains a list of (User Info Cl, User Info C2); U2U Relay D obtains an empty list; and U2U Relay E obtains a list of (User Info El).[000100] Suppose that UE Al wishes to discover UE El and establish point-to-point communication. Although UE El is reachable via the MANET by U2U Relay A, UE Al will not attempt a connection with U2U Relay A unless U2U Relay A advertises the availability of User Info El.[000101] To allow U2U Relay A to advertise the availability of User Info El, there the lists of discoverable UEs should be shared by all participating routers in the MANET. This can be done by defining a new MANET message called Discovery Info, as illustrated in FIG. 8. Upon reception of a Discovery Info message by a MANET router, the MANET router forwards a copy to the collocated U2U Relay. The U2U Relay updates the list of discovered User Info ID and advertises the updated list to End UEs in proximity.[000102] FIG. 9 illustrates signaling for connection establishment using the MANET routers of FIG. 8 in accordance with some embodiments. As shown by FIG. 9, once UE Al has determined that it can reach UE El via U2U Relay A, UE Al can send a Direct Communication Request to U2U Relay A, as illustrated with step 1 in FIG. 9. The Direct Communication Request is propagated to U2U Relay E (step 2 in FIG. 9) and delivered to UE El (step 3 in FIG. 9). Similar logic applies to the Direct Communication Accept message in the reverse direction (i.e., from UE El via U2U Relay E via U2U Relay A to UE Al).[000103] Point-to-point transport for signaling messages between a pair of U2U Relays is used to allow the propagation of Direct Communication messages over the MANET network. As a result of these enhancements, the entire MANET (with collocated U2U Relays) behaves as a single ProSe UE-to-UE Relay, with no impact on the End UEs.[000104] The Discovery Info message carries: Identity of the Relay that is originator of the Discovery Info message; List of locally discovered User Info IDs (per RSC); Signaling Endpoint Address (IP address and port number) that can be used for establishment of point-to-point signaling connection between a pair of U2U Relays over the MANET; and (optional) Security information related to establishment of point-to-point signaling connection between a pair of U2U Relays over the MANET.[000105] The Discovery Info message is diffused throughout the MANET using MPR flooding (as defined in IETF RFC 7181), if available. As an example, in reference to FIG. 8, by relying on MPR flooding, the Discovery Info is transmitted only on a subset of the network interfaces. If MPR is not available, then the Discovery Info message is diffused using simple flooding i.e., by transmitting a copy of the Discovery Info message on all interfaces (exceptthe one on which the message has been received). The 5G ProSe Multi-hop UE- to-UE Relay that has initiated transmission of the MANET Discovery Info message controls the propagation depth of the MANET Discovery Info message based on a configured parameter of "maximum number of hops per RSC." [000106] The Discovery Info message is formatted according to IETF RFC 5444. Specifically, the message originator address (<msg-orig-addr> in IETF RFC 5444) and the message sequence number (<msg-seq-num> in IETF RFC 5444) are used to enable the MPR flooding mechanism, as defined in IETF RFC 7181.[000107] Upon reception of a Discovery Info message, the MANET router forwards a copy to the collocated U2U Relay. The U2U Relay updates the list of User Info IDs that are reachable via the MANET network. For each stored User Info ID the U2U Relay keeps information of the U2U Relay that originated the information. In some embodiments, the same User Info ID can be associated with more than one U2U Relay (e.g., in case the UE was discovered by more than one U2U Relays).[000108] In an alternative embodiment, the content of the Discovery Info message described above may be carried as a new information element in the MANET TC message. In this case, however, the frequency of topology updates is different and unrelated from the frequency of End UE discovery events.[000109] In an alternative embodiment, the Discovery Info message is not a new MANET message, but is a part of a flooding-based signaling protocol that is defined on its own. In this case, however, this approach cannot readily re-use the MPR flooding mechanisms that are built-in features in MANET.[000110] The signaling protocol carrying the Direct Communication messages (as defined in 3GPP TS 23.304) between a pair of U2U Relays can be defined by 3GPP. The Discovery Info is to be able to carry the Signaling Endpoint Address (IP address and port number) that uniquely identifies the signaling endpoint of the U2U Relay functionality collocated with the MANET router.[000111] When the local U2U Relay (e.g., U2U Relay A) receives a Direct Communication Request from the source End UE and the target End UE has been discovered by more than one remote U2U Relay (e.g., U2U Relay B andU2U Relay C), the local U2U Relay chooses to which remote U2U Relay to forward the Direct Communication Request based on implementation.[000112] Upon reception of the Direct Communication Accept from the remote U2U Relay, the local U2U Relay forwards the Direct Communication Accept message to the source End UE.[000113] The IP subnet address / prefix that is used by U2U Relay to assign IP addresses to End UEs, as well as the Signaling Endpoint Address of the U2U Relay functionality, is advertised by the collocated MANET router via MANET TC messages ahead of time. This is to ensure the existence of stable routes prior to the establishment of a signaling connection between a pair of U2U Relays, or prior to the exchange of user plane packets between a pair of distant End UEs.[000114] If a MANET router happens to include a ProSe UE-to-Network functionality, the Discovery Info message indicates that the Relay that is originator of the Discovery Info message has UE-to-Network functionality and includes RSC of the collocated ProSe UE-to-Network Relay. RSC indicates the connectivity service that the ProSe UE-to-Network Relay provides to the Remote UE.[000115] In an alternative embodiment, the End UE establishes a Layer-2 link with the local U2U Relay without performing prior discovery, as described in steps 3, 4 and 9 of FIG. 6. At the end of the Layer-2 link establishment, the End UE is allocated an IP address / prefix, as described in step 10 of FIG. 6. At any time after the successful Layer-2 link establishment, the local U2U Relay initiates the sending of the Discovery Info message, as defined above, to update the other U2U Relays about the presence of a new End UE. The Discovery Info message additionally carries the IP address / prefix of the End UE.[000116] When a source End UE wishes to communicate with a target End UE, the source End UE performs a DNS query with the local U2U Relay to discover the IP address / prefix of the target End UE, as described in step 11 of FIG. 6.[000117] As described above, the information in the Discovery Info message can alternatively be propagated using the MANET TC message. Alternatively, the local U2U Relay can update all other U2U Relays using dynamic DNS updates (as defined in IETF RFC 2136).[000118] Examples[000119] Example 1 is an apparatus of a user equipment (UE) configured to act as a 5th generation (5G) Proximity Services (ProSe) multi-hop UE-to-UE Relay in a Mobile Ad-hoc Network (MANET), the apparatus comprising a processor that configures the apparatus to: obtain an Internet Protocol (IP) address / prefix of a target 5G ProSe End UE via Domain Name System (DNS) queries; and after obtaining the IP address / prefix of the target 5G ProSe End UE, use a dedicated MANET Discovery Info message to propagate DNS information of the target 5G ProSe End UE to at least one other 5G ProSe multi -hop UE-to- UE Relay of the MANET.[000120] In Example 2, the subject matter of Example 1 includes, wherein the processor further configures the apparatus to use Multipoint Relay flooding to diffuse the dedicated MANET Discovery Info message through the MANET. [000121] In Example 3, the subject matter of Examples 1-2 includes, wherein the processor further configures the apparatus to use simple flooding to diffuse the dedicated MANET Discovery Info message through the MANET by transmitting a copy of the dedicated MANET Discovery Info message on all PC5 interfaces of the 5G ProSe multi-hop UE-to-UE Relay except a PC5 interface on which the dedicated MANET Discovery Info message has been received.[000122] In Example 4, the subject matter of Examples 1-3 includes, wherein the processor further configures the apparatus to determine a propagation depth of the dedicated MANET Discovery Info message based on a configured maximum number of hops per Relay Service Code (RSC).[000123] In Example 5, the subject matter of Examples 1-4 includes, wherein the processor further configures the apparatus to, in response to reception of the dedicated MANET Discovery Info message, update a routing table in the 5G ProSe multi-hop UE-to-UE Relay to indicate routing to the target 5G ProSe End UE through other 5G ProSe multi -hop UE-to-UE Relays of the MANET.[000124] In Example 6, the subject matter of Example 5 includes, wherein the routing table comprises discovered User Info IDs and associated IPaddresses / prefixes, if available, of 5G ProSe End UEs with a 5G ProSe multihop UE-to-UE Relay identity through which each of the discovered User Info IDs is reachable.[000125] In Example 7, the subject matter of Examples 5-6 includes, wherein the processor further configures the apparatus to, in response to reception of the dedicated MANET Discovery Info message, trigger MANET signaling to the other 5G ProSe multi-hop UE-to-UE Relays to update a routing table in the other 5G ProSe multi-hop UE-to-UE Relays to indicate routing to the target 5G ProSe End UE.[000126] In Example 8, the subject matter of Example 7 includes, wherein the processor further configures the apparatus to, in response to reception of the dedicated MANET Discovery Info message, use the dedicated MANET Discovery Info message to the other 5G ProSe multi-hop UE-to-UE Relays to update DNS entries in the other 5G ProSe multi-hop UE-to-UE Relays.[000127] In Example 9, the subject matter of Examples 1-8 includes, wherein the processor further configures the apparatus to: perform ProSe Discovery of 5G ProSe End UEs in proximity of the 5G ProSe multi-hop UE-to- UE Relay and create a list of locally discovered User Info IDs; and announce to 5G ProSe UEs within range of the 5G ProSe multi-hop UE-to-UE Relay, via the dedicated MANET Discovery Info message, End UEs reachable by the 5G ProSe multi-hop UE-to-UE Relay for diffusion of the list of locally discovered User Info IDs via the MANET towards remote 5G ProSe multi-hop UE-to-UE Relays.[000128] In Example 10, the subject matter of Example 9 includes, wherein the dedicated MANET Discovery Info message comprises an identity of the 5G ProSe multi-hop UE-to-UE Relay that is originator of the dedicated MANET Discovery Info message, a Signaling Endpoint Address including IP address and port number that can be used for establishment of a point-to-point signaling connection between a pair of 5G ProSe multi-hop UE-to-UE Relays over the MANET, and security information for the establishment of the point-to-point signaling connection between the pair of 5G ProSe multi-hop UE-to-UE Relays over the MANET.[000129] In Example 11, the subject matter of Examples 9-10 includes, wherein the dedicated MANET Discovery Info message comprises, for each 5G ProSe End UE that has an established Layer-2 link with the 5G ProSe multi-hop UE-to-UE Relay, an IP address / prefix of the 5G ProSe End UE in association with User Info ID of the 5G ProSe End UE.[000130] In Example 12, the subject matter of Examples 1-11 includes, wherein the processor further configures the apparatus to: receive a Direct Communication Request from a source 5G ProSe End UE to establish communication with the target 5G ProSe End UE that is discovered by a remote 5G ProSe multi -hop UE-to-UE Relay; determine an identity of the remote 5G ProSe multi-hop UE-to-UE Relay based on stored information that includes a Signaling Endpoint Address; forward the Direct Communication Request to the remote 5G ProSe multi-hop UE-to-UE Relay using the stored Signaling Endpoint Address of the remote 5G ProSe multi-hop UE-to-UE Relay; and tunnel subsequent Direct Communication-related messages between the source 5G ProSe End UE and the target 5G ProSe End UE via a signaling connection established between the 5G ProSe multi-hop UE-to-UE Relay and the remote 5G ProSe multi -hop UE-to-UE Relay.[000131] In Example 13, the subject matter of Examples 1-12 includes, wherein: the 5G ProSe multi-hop UE-to-UE Relay has a collocated MANET router that connects with MANET functionality of neighboring MANET routers and establishes the MANET, and the processor further configures the collocated MANET router to use MANET Topology Control (TC) messages to advertise: an IP subnet address / prefix used by the 5G ProSe multi-hop UE-to-UE Relay to assign IP addresses to End UEs, and a signaling Endpoint Address of the 5G ProSe multi -hop UE-to-UE Relay.[000132] In Example 14, the subject matter of Examples 1-13 includes, wherein the dedicated MANET Discovery Info message indicates that an originating 5G ProSe multi-hop UE-to-UE Relay that is an originator of the dedicated MANET Discovery Info message has UE-to-Network functionality, the dedicated MANET Discovery Info message comprising a Relay Service Code (RSC) of the originating 5G ProSe multi-hop UE-to-UE Relay.[000133] In Example 15, the subject matter of Examples 1-14 includes, wherein content of the dedicated MANET Discovery Info message is diffused through the MANET using new information elements in MANET Topology Control (TC) messages.[000134] Example 16 is a non-transitory computer-readable storage medium that stores instructions for execution by one or more processors of an apparatus of a user equipment (UE) configured to act as a 5th generation (5G) Proximity Services (ProSe) multi-hop UE-to-UE Relay in a Mobile Ad-hoc Network (MANET), the instructions, when executed, configured to cause the apparatus to: establish multiple Layer-2 links with other 5G ProSe multi -hop UE-to-UE Relays supporting a same Relay Service Code (RSC); obtain an Internet Protocol (IP) address / prefix of a target 5G ProSe End UE, each 5G ProSe End UE associated with the RSC having a unique IP address / prefix; and use a dedicated MANET Discovery Info message to propagate User Info ID and the IP address / prefix of the target 5G ProSe End UE to the other 5G ProSe multi -hop UE-to-UE Relays.[000135] In Example 17, the subject matter of Example 16 includes, wherein the instructions, when executed, configure the apparatus to use Multipoint Relay flooding to diffuse the dedicated MANET Discovery Info message through the MANET.[000136] In Example 18, the subject matter of Examples 16-17 includes, wherein the instructions, when executed, configure the apparatus to use simple flooding to diffuse the dedicated MANET Discovery Info message through the MANET by transmitting a copy of the dedicated MANET Discovery Info message on all PC5 interfaces except a PC5 interface on which the dedicated MANET Discovery Info message has been received.[000137] Example 19 is an apparatus of a user equipment (UE) configured to act as a 5th generation (5G) Proximity Services (ProSe) multi-hop UE-to-UE Relay in a Mobile Ad-hoc Network (MANET), the apparatus comprising a processor that configures the apparatus to: establish multiple Layer-2 links with other 5G ProSe multi -hop UE-to-UE Relays supporting a same Relay Service Code (RSC); establish a Layer-2 link with a source 5G ProSe End UE; after establishment of the Layer-2 link with the source 5G ProSe End UE, update arouting table in the 5G ProSe multi-hop UE-to-UE Relay to include, connectivity of the 5G ProSe multi -hop UE-to-UE Relay with the source 5G ProSe End UE, the routing table including routing in the MANET to a target 5G ProSe End UE; use a dedicated MANET Discovery Info message to update Domain Name System (DNS) entries in the other 5G ProSe multi-hop UE-to-UE Relays to indicate the connectivity of the 5G ProSe multi-hop UE-to-UE Relay with the source 5G ProSe End UE; receive a DNS query from the source 5G ProSe End UE for the target 5G ProSe End UE; and after the DNS query, forward packets between the source 5G ProSe End UE and the target 5G ProSe End UE based on the routing table.[000138] In Example 20, the subject matter of Example 19 includes, wherein the processor further configures the apparatus to, after establishment of the Layer-2 link with the source 5G ProSe End UE, use MANET signaling to update a routing table in the other 5G ProSe multi-hop UE-to-UE Relays to indicate the connectivity of the 5G ProSe multi-hop UE-to-UE Relay with the source 5G ProSe End UE.[000139] Example 21 is at least one machine-readable medium including instructions that, when executed by processing circuitry, cause the processing circuitry to perform operations to implement of any of Examples 1-20.[000140] Example 22 is an apparatus comprising means to implement of any of Examples 1-20.[000141] Example 23 is a system to implement of any of Examples 1-20.[000142] Example 24 is a method to implement of any of Examples 1-20.[000143] Although an embodiment has been described with reference to specific example embodiments, it will be evident that various modifications and changes may be made to these embodiments without departing from the broader scope of the present disclosure. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense. The accompanying drawings that form a part hereof show, by way of illustration, and not of limitation, specific embodiments in which the subject matter may be practiced. The embodiments illustrated are described in sufficient detail to enable those skilled in the art to practice the teachings disclosed herein. Other embodiments may be utilized and derived therefrom, such that structural andlogical substitutions and changes may be made without departing from the scope of this disclosure. This Detailed Description, therefore, is not to be taken in a limiting sense, and the scope of various embodiments is defined only by the appended claims, along with the full range of equivalents to which such claims are entitled.[000144] The subject matter may be referred to herein, individually and / or collectively, by the term “embodiment” merely for convenience and without intending to voluntarily limit the scope of this application to any single inventive concept if more than one is in fact disclosed. Thus, although specific embodiments have been illustrated and described herein, it should be appreciated that any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description. [000145] In this document, the terms "a" or "an" are used, as is common in patent documents, to indicate one or more than one, independent of any other instances or usages of "at least one" or "one or more." In this document, the term "or" is used to refer to a nonexclusive or, such that "A or B" includes "A but not B," "B but not A," and "A and B," unless otherwise indicated. In this document, the terms "including" and "in which" are used as the plain-English equivalents of the respective terms "comprising" and "wherein." Also, in the following claims, the terms "including" and "comprising" are open-ended, that is, a system, UE, article, composition, formulation, or process that includes elements in addition to those listed after such a term in a claim are still deemed to fall within the scope of that claim. Moreover, in the following claims, the terms "first," "second," and "third," etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. As indicated herein, although the term “a” is used herein, one or more of the associated elements may be used in different embodiments. For example, the term “a processor” configured to carry out specific operations includes both a single processor configured to carry out all of the operations as well as multiple processors individually configured to carry out some or all of the operations (which mayoverlap) such that the combination of processors carry out all of the operations. Further, the term “includes” may be considered to be interpreted as “includes at least” the elements that follow.[000146] The Abstract of the Disclosure is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, it may be seen that various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment.

Claims

CLAIMSWhat is claimed is:

1. An apparatus of a user equipment (UE) configured to act as a 5thgeneration (5G) Proximity Services (ProSe) multi-hop UE-to-UE Relay in a Mobile Ad-hoc Network (MANET), the apparatus comprising a processor that configures the apparatus to: obtain an Internet Protocol (IP) address / prefix of a target 5G ProSe End UE via Domain Name System (DNS) queries; and after obtaining the IP address / prefix of the target 5G ProSe End UE, use a dedicated MANET Discovery Info message to propagate DNS information of the target 5G ProSe End UE to at least one other 5G ProSe multi -hop UE-to-UE Relay of the MANET.

2. The apparatus of claim 1, wherein the processor further configures the apparatus to use Multipoint Relay flooding to diffuse the dedicated MANET Discovery Info message through the MANET.

3. The apparatus of claim 1, wherein the processor further configures the apparatus to use simple flooding to diffuse the dedicated MANET Discovery Info message through the MANET by transmitting a copy of the dedicated MANET Discovery Info message on all PC5 interfaces of the 5G ProSe multihop UE-to-UE Relay except a PC5 interface on which the dedicated MANET Discovery Info message has been received.

4. The apparatus of claim 1, wherein the processor further configures the apparatus to, in response to reception of the dedicated MANET Discovery Info message, update a routing table in the 5G ProSe multi-hop UE-to-UE Relay to indicate routing to the target 5G ProSe End UE through other 5G ProSe multihop UE-to-UE Relays of the MANET.

5. The apparatus of claim 4, wherein the routing table comprises discovered User Info IDs and associated IP addresses / prefixes, if available, of 5G ProSeEnd UEs with a 5G ProSe multi -hop UE-to-UE Relay identity through which each of the discovered User Info IDs is reachable.

6. The apparatus of claim 4, wherein the processor further configures the apparatus to, in response to reception of the dedicated MANET Discovery Info message, trigger MANET signaling to the other 5G ProSe multi-hop UE-to-UE Relays to update a routing table in the other 5G ProSe multi-hop UE-to-UE Relays to indicate routing to the target 5G ProSe End UE.

7. The apparatus of claim 6, wherein the processor further configures the apparatus to, in response to reception of the dedicated MANET Discovery Info message, use the dedicated MANET Discovery Info message to the other 5G ProSe multi-hop UE-to-UE Relays to update DNS entries in the other 5G ProSe multi -hop UE-to-UE Relays.

8. The apparatus of claim 1, wherein the processor further configures the apparatus to determine a propagation depth of the dedicated MANET Discovery Info message based on a configured maximum number of hops per Relay Service Code (RSC).

9. The apparatus of claim 1, wherein the processor further configures the apparatus to: perform ProSe Discovery of 5G ProSe End UEs in proximity of the 5G ProSe multi-hop UE-to-UE Relay and create a list of locally discovered User Info IDs; and announce to 5G ProSe UEs within range of the 5G ProSe multi-hop UE- to-UE Relay, via the dedicated MANET Discovery Info message, End UEs reachable by the 5G ProSe multi-hop UE-to-UE Relay for diffusion of the list of locally discovered User Info IDs via the MANET towards remote 5G ProSe multi -hop UE-to-UE Relays.

10. The apparatus of claim 9, wherein the dedicated MANET Discovery Info message comprises an identity of the 5G ProSe multi-hop UE-to-UE Relay thatis originator of the dedicated MANET Discovery Info message, a Signaling Endpoint Address including IP address and port number that can be used for establishment of a point-to-point signaling connection between a pair of 5G ProSe multi-hop UE-to-UE Relays over the MANET, and security information for the establishment of the point-to-point signaling connection between the pair of 5G ProSe multi -hop UE-to-UE Relays over the MANET.

11. The apparatus of claim 9, wherein the dedicated MANET Discovery Info message comprises, for each 5G ProSe End UE that has an established Layer-2 link with the 5G ProSe multi-hop UE-to-UE Relay, an IP address / prefix of the 5G ProSe End UE in association with User Info ID of the 5G ProSe End UE.

12. The apparatus of claim 1, wherein the processor further configures the apparatus to: receive a Direct Communication Request from a source 5G ProSe End UE to establish communication with the target 5G ProSe End UE that is discovered by a remote 5G ProSe multi-hop UE-to-UE Relay; determine an identity of the remote 5G ProSe multi-hop UE-to-UE Relay based on stored information that includes a Signaling Endpoint Address; forward the Direct Communication Request to the remote 5G ProSe multi-hop UE-to-UE Relay using the stored Signaling Endpoint Address of the remote 5G ProSe multi-hop UE-to-UE Relay; and tunnel subsequent Direct Communication-related messages between the source 5G ProSe End UE and the target 5G ProSe End UE via a signaling connection established between the 5G ProSe multi-hop UE-to-UE Relay and the remote 5G ProSe multi-hop UE-to-UE Relay.

13. The apparatus of claim 1, wherein: the 5G ProSe multi-hop UE-to-UE Relay has a collocated MANET router that connects with MANET functionality of neighboring MANET routers and establishes the MANET, and the processor further configures the collocated MANET router to use MANET Topology Control (TC) messages to advertise:an IP subnet address / prefix used by the 5G ProSe multi-hop UE- to-UE Relay to assign IP addresses to End UEs, and a signaling Endpoint Address of the 5G ProSe multi-hop UE-to- UE Relay.

14. The apparatus of claim 1, wherein the dedicated MANET Discovery Info message indicates that an originating 5G ProSe multi-hop UE-to-UE Relay that is an originator of the dedicated MANET Discovery Info message has UE-to- Network functionality, the dedicated MANET Discovery Info message comprising a Relay Service Code (RSC) of the originating 5G ProSe multi-hop UE-to-UE Relay.

15. The apparatus of claim 1, wherein content of the dedicated MANET Discovery Info message is diffused through the MANET using new information elements in MANET Topology Control (TC) messages.

16. A computer-readable storage medium that stores instructions for execution by one or more processors of an apparatus of a user equipment (UE) configured to act as a 5thgeneration (5G) Proximity Services (ProSe) multi-hop UE-to-UE Relay in a Mobile Ad-hoc Network (MANET), the instructions, when executed, configured to cause the apparatus to: establish multiple Layer-2 links with other 5G ProSe multi-hop UE-to- UE Relays supporting a same Relay Service Code (RSC); obtain an Internet Protocol (IP) address / prefix of a target 5G ProSe End UE, each 5G ProSe End UE associated with the RSC having a unique IP address / prefix; and use a dedicated MANET Discovery Info message to propagate User Info ID and the IP address / prefix of the target 5G ProSe End UE to the other 5G ProSe multi -hop UE-to-UE Relays.

17. The computer-readable storage medium of claim 16, wherein the instructions, when executed, configure the apparatus to use Multipoint Relay flooding to diffuse the dedicated MANET Discovery Info message through the MANET.

18. The computer-readable storage medium of claim 16, wherein the instructions, when executed, configure the apparatus to use simple flooding to diffuse the dedicated MANET Discovery Info message through the MANET by transmitting a copy of the dedicated MANET Discovery Info message on all PC5 interfaces except a PC5 interface on which the dedicated MANET Discovery Info message has been received.

19. An apparatus of a user equipment (UE) configured to act as a 5thgeneration (5G) Proximity Services (ProSe) multi-hop UE-to-UE Relay in a Mobile Ad-hoc Network (MANET), the apparatus comprising a processor that configures the apparatus to: establish multiple Layer-2 links with other 5G ProSe multi-hop UE-to- UE Relays supporting a same Relay Service Code (RSC); establish a Layer-2 link with a source 5G ProSe End UE; after establishment of the Layer-2 link with the source 5G ProSe End UE, update a routing table in the 5G ProSe multi-hop UE-to-UE Relay to include connectivity of the 5G ProSe multi-hop UE-to-UE Relay with the source 5G ProSe End UE, the routing table including routing in the MANET to a target 5G ProSe End UE; use a dedicated MANET Discovery Info message to update Domain Name System (DNS) entries in the other 5G ProSe multi-hop UE-to-UE Relays to indicate the connectivity of the 5G ProSe multi-hop UE-to-UE Relay with the source 5G ProSe End UE; receive a DNS query from the source 5G ProSe End UE for the target 5G ProSe End UE; and after the DNS query, forward packets between the source 5G ProSe End UE and the target 5G ProSe End UE based on the routing table.

20. The apparatus of claim 19, wherein the processor further configures the apparatus to, after establishment of the Layer-2 link with the source 5G ProSe End UE, use MANET signaling to update a routing table in the other 5G ProSemulti-hop UE-to-UE Relays to indicate the connectivity of the 5G ProSe multihop UE-to-UE Relay with the source 5G ProSe End UE.

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