NR relay method for multipath detection, relay selection, and network reporting

Abstract

A wireless transmit / receive unit (WTRU) may receive configuration information that may indicate one or more parameters for operating as a WTRU-to-network mobile relay. The parameters may include a first reference signal power (RSRP) threshold and / or a second RSRP threshold. The WTRU may perform RSRP measurements of a serving cell to determine the RSRP value. The WTRU may determine whether to indicate support for one or more of single-path operation and multipath operation in a sidelink discovery message based on the RSRP value. The WTRU may indicate support for multipath relay operation based on the RSRP value satisfying the second RSRP threshold. The WTRU may indicate support for single-path relay operation based on the RSRP value satisfying the first RSRP threshold. The WTRU may transmit a sidelink discovery message indicating support for single-path relay operation and / or multipath relay operation based on the RSRP value.

Description

Technical Field

[0001] (Cross - reference to related applications) This application claims the benefit of U.S. Provisional Patent Application No. 63 / 327,578, filed Apr. 5, 2022; U.S. Provisional Patent Application No. 63 / 410,817, filed Sep. 28, 2022; and U.S. Provisional Patent Application No. 63 / 445,332, filed Feb. 14, 2023, the entire contents of which are incorporated herein by reference.

Background Art

[0002] New Radio (NR) side - link relay can be implemented. For example, wireless - to - network (W2N) relay from a wireless transmit / receive unit (WTRU) to a network and / or WTRU - to - WTRU (W2W) relay can be used based on PC5 (e.g., side - link).

[0003] NR side - link can be focused on supporting vehicle - to - everything (V2X) related road safety services. For example, support for broadcast communication, group - cast communication, and / or unicast communication in both out - of - coverage scenarios and in - network - coverage scenarios can be provided. Considering a wider range of applications and services, a side - link - based relay function can be considered to expand side - link / network coverage and improve power efficiency.

[0004] W2N coverage can be extended. Uu coverage reachability can be useful for a WTRU to reach a server within a PDN network or a corresponding WTRU outside a proximity area. However, current solutions for W2N relay may be limited to EUTRA - based technologies and thus may not be applicable to an NR - based system for both NG - RAN and NR - based side - link communication.

[0005] W2W coverage can be extended. Proximity reachability may be limited to single-hop sidelink links via either EUTRA-based or NR-based sidelink technology. However, given the limited single-hop sidelink coverage, this may not be sufficient in scenarios where Uu coverage is absent. Sidelink connectivity can be further extended within the NR framework to support enhanced quality of service (QoS) requirements. [Overview of the Initiative]

[0006] Discover transmissions may be performed. A WTRU may support and / or request one or more relay services. A WTRU may perform discover-relay-service message transmissions. A WTRU may receive (pre)configurations for discover-relay-service transmissions. A WTRU may indicate its supported relay service capabilities to the network. A WTRU may receive instructions from the network indicating the type of relay (e.g., what type of relay it should be). A WTRU may request resources for discover-relay-service transmissions. A WTRU may perform discover-relay-service message transmissions. A WTRU may determine which discover-relay-service message to send. A WTRU may determine the quality of service associated with a discover-relay-service message. A WTRU may determine the resource pool for sending discover-relay-service messages. A WTRU may determine the transmission parameters for a discover-relay-service message. A WTRU may determine the information to include in a discover message.

[0007] Relay selection may be performed. The WTRU may trigger relay selection. The WTRU may determine which relays should be (re)selected. The WTRU may determine whether relay reselection should be performed and / or whether the set of relays detected should be reported to the network.

[0008] A WTRU may report a set of discovered remote WTRUs and / or a set of discovered relays. A WTRU may request resources for a discover-relay-service transmission. A WTRU may receive instructions to send a discover-relay-service message. A WTRU may trigger cell reselection. A WTRU may determine which cells should be prioritized / reported.

[0009] In the example, a WTRU (e.g., a relay WTRU) may determine which discover-relay-service message to send, one or more discover-transmit parameters, and one or more resource pools to send the discover-message to, based on the Uu reference signal receive power (RSRP), relay load, and / or WTRU relay capability.

[0010] For example, a WTRU may be (pre)configured with conditions for sending multipath and / or singlepath discovery messages (e.g., via a dedicated RRC or SIB). Alternatively or additionally, a WTRU may receive conditions for sending multipath and / or singlepath discovery messages (e.g., via a dedicated RRC or SIB). A discovery message may include one or more of the following: Uu RSRP ranges for single-path discovery (e.g., minimum and maximum Uu RSRP), (e.g., different) minimum Uu RSRPs for multipath discovery, relay capabilities (e.g., may include support for single-path and / or multipath relays), and / or quality of service (QoS) (e.g., priority), and one or more of the transmission resource pools for one or more (e.g., each) types of discovery messages. A WTRU may determine which type of discovery message to send based on one or more of its measured Uu RSRP, relay load, and WTRU capabilities to support multipath and / or single-path relays. In the example, a WTRU may allow sending single-path discoveries (e.g., only) in high-load cases (e.g., network expansion may be prioritized). A WTRU may select a resource pool for sending discovery messages based on the discovery type. A WTRU may use the (pre)configured QoS for discovery messages to determine the transmission parameters for discovery messages. A WTRU may include the discovery type (e.g., single-path and / or multipath), Uu RSRP (for example, for a remote WTRU to perform relay selection) and / or one or more of the QoS of the discovery message within the discovery message may be indicated. The WTRU may perform discovery transmission.

[0011] In the example, a WTRU (e.g., a remote WTRU) may determine whether to transmit single-path discovery and / or multipath discovery based on one or more of the following: its measured Uu RSRP, receipt of SLRB / LCH configuration for multipath, and / or incoming data from a set of SLRB / LCH into a buffer. When transmitting multipath discovery, the WTRU may select / report (e.g., to the gNB) a set of relays that support multipath and have appropriate Uu RSRP.

[0012] For example, a WTRU (e.g., a remote WTRU) may be (pre) configured with conditions for sending discovery messages, or may receive conditions (e.g., via a dedicated RRC or SIB). A discovery message may include one or more of the following: a maximum Uu RSRP for single-path discovery, a range of Uu RSRPs for multipath discovery (e.g., minimum and (e.g., different) maximum Uu RSRPs), a set of SLRB / LCHs to trigger multipath discovery, and / or the minimum Uu RSRP for each relay per SLRB / LCH. When an SLRB / LCH configuration is received and / or SLRB / LCH data arrives that satisfies the configured conditions for multipath relaying, the WTRU may trigger a discovery transmission, perform relay response reception, and / or perform relay selection, or select a set of relays to announce to the network that satisfy the following conditions: supporting multipath, supporting established SLRB / LCHs, and the relay's Uu RSRP is higher than a threshold that can be obtained based on the remote WTRU's SLRB / LCH. For example, if the Uu threshold for single-path transmission is not met but the threshold for multipath discovery is met, the WTRU may, upon receiving an SLRB / LCH configuration and / or when SLRB / LCH data arrives that meets the configured conditions for multipath relay, trigger a discovery transmission, perform a relay response reception and / or perform a relay selection, or select a set of relays to advertise to the network that meet the following conditions: support multipath, support an established SLRB / LCH, and the relay's Uu RSRP is higher than the threshold that can be obtained based on the remote WTRU's SLRB / LCH.

[0013] A relay WTRU may determine which set of discovered remote WTRUs should be reported to the network. Additionally or alternatively, a WTRU (e.g., a relay WTRU) may determine which set of discovered relays should be reported to the network. A relay WTRU may indicate (e.g., send) information in its discovery message. A remote WTRU may indicate (e.g., send) its Uu connection status in its discovery service message. A WTRU may decide to send a discovery-relay-service message. A WTRU may determine whether a cell supports one or more relay services. A WTRU may determine whether to send a discovery-relay-service message based on instructions from the cell. A WTRU may determine whether to respond to (e.g., send) a remote WTRU. A WTRU may determine its load.

[0014] A WTRU (e.g., a first WTRU) may monitor one or more discovery messages. These discovery messages may be from one or more second WTRUs. The WTRU may, for example, determine a set of one or more second WTRUs based on the discovery messages. The WTRU may report this set of second WTRUs to the network, for example. The set of one or more second WTRUs may be based on their support type. The support type may include one or more of single-path and multi-path services. The WTRU may compare the reference signal received power (RSRP) of a second WTRU to a threshold. The WTRU may determine the support type based on the comparison of the second WTRU RSRP with the threshold. For example, if the second WTRU RSRP is below the threshold, the WTRU may determine that the support type is single-path service. In another example, if the second WTRU RSRP is below the threshold, the WTRU may determine that the support type is single-path service. The WTRU may determine its support type based on the connectivity status of the second WTRU. The WTRU may compare the quality of service (QoS) of the second WTRU to a threshold.

[0015] A WTRU (e.g., a relay WTRU) may receive configuration information. This configuration information may include one or more parameters. These one or more parameters may be necessary for the WTRU to operate as a mobile relay between networks. Additionally or alternatively, the parameters may include a first reference signal power (RSRP) threshold and / or a second RSRP threshold.

[0016] A WTRU may, for example, perform an RSRP measurement to determine the RSRP value. For example, a WTRU may receive a signal from a network (e.g., a serving cell of the network) and perform an RSRP measurement on the received signal. A WTRU may determine whether it supports one or more of single-path and multi-path operations. For example, a WTRU may determine whether it supports one or more of single-path and multi-path operations in a sidelink discovery message based on the RSRP value. A WTRU may indicate support for multi-path relay operation based on the RSRP value meeting a second RSRP threshold. Additionally or alternatively, a WTRU may indicate support for single-path relay operation based on the RSRP value meeting a first RSRP threshold. A WTRU may, for example, send a sidelink discovery message indicating support for one or more of single-path and multi-path relay operations. For example, a WTRU may send a sidelink discovery message indicating support for one or more of single-path and multi-path relay operations based on the RSRP value.

[0017] The parameters may include the relay load range. WTRU may indicate support for multipath relay operation based on, for example, whether the current relay load of the WTRU is below the relay load range. The parameters may include an indication for a first resource pool and / or a second resource pool. The first resource pool may be, for example, a resource pool for sending a first sidelink discovery message indicating support for single-path relay operation. The second resource pool may be, for example, a resource pool for sending a second sidelink discovery message indicating support for multipath relay operation. The sidelink discovery message may indicate an RSRP value. WTRU may indicate support for single-path relay operation when the RSRP value is greater than or equal to a first RSRP threshold. Additionally or alternatively, WTRU may indicate support for single-path relay operation when the RSRP value is less than a second RSRP threshold.

[0018] A WTRU may indicate support for multipath relay operation when the RSRP value is equal to or greater than a second RSRP threshold. A WTRU may, for example, send a report to the network based on the RSRP value. The report may indicate one or more second WTRUs. For example, the report may indicate one or more second WTRUs requesting single-path relay operation when the RSRP value meets the first RSRP threshold. Additionally or alternatively, the report may indicate that one or more second WTRUs are requesting multipath relay operation when the RSRP value meets the second RSRP threshold. [Brief explanation of the drawing]

[0019] [Figure 1A] This is a system diagram illustrating an exemplary communication system in which one or more disclosed embodiments may be implemented. [Figure 1B] This is a system diagram illustrating an exemplary wireless transmit / receive unit (WTRU) that may be used in a communication system illustrated in Figure 1A, according to one embodiment. [Figure 1C]This is a system diagram illustrating an exemplary radio access network (RAN) and an exemplary core network (CN) that may be used in a communication system illustrated in Figure 1A according to one embodiment. [Figure 1D] This is a system diagram illustrating a further exemplary RAN and a further exemplary CN that may be used in the communication system illustrated in Figure 1A according to one embodiment. [Figure 2] This document illustrates an exemplary user-plane radio protocol stack for an L2-evolved WTRU-to-network relay (e.g., PC5). [Figure 3] This example illustrates a control plane radio protocol stack for an L2 evolved WTRU-to-network relay (e.g., PC5). [Figure 4] This section provides an example of a WTRU (Write-Through Rule) used to determine whether to send a single-path discovery versus multi-path discovery and a single-path request versus a multi-path request. [Figure 5] This illustrates an example where a remote WTRU prioritizes a relay WTRU associated with a gNB that has a measured Uu RSRP above a threshold. [Figure 6] This example illustrates a relay WTRU that determines whether to send a single-path discovery versus multi-path discovery based on whether the measured Uu RSRP is above a threshold. [Modes for carrying out the invention]

[0020] Exemplary network for embodiments of the present invention FIG. 1A is a diagram illustrating an exemplary communication system 100 in which one or more of the disclosed embodiments may be implemented. The communication system 100 may be a multiple access system that provides content such as voice, data, video, messaging, broadcast, etc. to a plurality of wireless users. The communication system 100 may enable a plurality of wireless users to access such content through sharing of system resources including wireless bandwidth. For example, the communication system 100 may use one or more channel access methods such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), zero-tail unique-word DFT-Spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, filter bank multicarrier (FBMC), etc.

[0021] As shown in Figure 1A, the communication system 100 may include radio transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, RAN 104 / 113, CN 106 / 115, public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, but it will be understood that the disclosed embodiments intend any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a radio environment. For example, WTRU102a, 102b, 102c, 102d, any of which may be referred to as “station” and / or “STA”, may be configured to transmit and / or receive radio signals and may include user equipment (UE), mobile stations, fixed subscriber units or mobile subscriber units, subscriber-based units, pagers, mobile phones, personal digital assistants (PDAs), smartphones, laptops, netbooks, personal computers, radio sensors, hotspots or Mi-Fi devices, Internet of Things (IoT) devices, watches or other wearable devices, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., for remote surgery), industrial devices and applications (e.g., robots and / or other radio devices operating in an industrial and / or automated processing chain context), consumer electronics devices, devices operating on commercial radio networks and / or industrial radio networks, etc. WTRU102a, 102b, 102c, and 102d can all be referred to as UE for compatibility purposes.

[0022] The communication system 100 may also include base station 114a and / or base station 114b. Each of base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks such as CN106 / 115, the Internet 110, and / or other network 112. By way of example, base stations 114a, 114b may be a base transceiver station (BTS), Node B, eNode B, home Node B, home eNode B, gNB, NR Node B, site controller, access point (AP), wireless router, etc. Although base stations 114a, 114b are each depicted as a single element, it will be understood that base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0023] Base station 114a may be part of RAN 104 / 113, which may also include other base stations and / or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), and relay nodes. Base station 114a and / or base station 114b may be configured to transmit and / or receive radio signals on one or more carrier frequencies, which may be referred to as cells (not shown). These frequencies may be licensed spectra, unlicensed spectra, or combinations of licensed and unlicensed spectra. Cells may provide coverage of radio services to a particular geographic area that may be relatively fixed or change over time. Cells may be further divided into cell sectors. For example, a cell associated with base station 114a may be divided into three sectors. Thus, in one embodiment, base station 114a may include three transceivers, i.e., one transceiver per sector of the cell. In one embodiment, the base station 114a may employ multiple-input multiple output (MIMO) technology and utilize multiple transceivers for each sector of the cell. For example, beamforming may be used to transmit and / or receive signals in a desired spatial direction.

[0024] Base stations 114a and 114b may communicate with one or more WTRUs 102a, 102b, 102c, and 102d via an air interface 116, which may be any suitable radio communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

[0025] More specifically, as described above, the communication system 100 may be a multiple access system, but may use one or more channel access schemes such as CDMA, TDMA, FDMA, OFDMA, and SC-FDMA. For example, base stations 114a and WTRUs 102a, 102b, and 102c within RAN 104 / 113 may implement radio technologies such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may use wideband CDMA (WCDMA) to establish air interfaces 115 / 116 / 117. WCDMA may include communication protocols such as High-Speed ​​Packet Access (HSPA) and / or Advanced HSPA (HSPA+). HSPA may include High-Speed ​​Downlink Packet Access (HSDPA) and / or High-Speed ​​UL Packet Access (HSUPA).

[0026] In one embodiment, base stations 114a and WTRUs 102a, 102b, and 102c may implement radio technologies such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish an air interface 116 using Long Term Evolution (LTE) and / or LTE-Advanced (LTE-A) and / or LTE-Advanced Pro (LTE-A Pro).

[0027] In one embodiment, base station 114a and WTRU 102a, 102b, 102c may implement radio technologies such as NR radio access, which can establish an air interface 116 using New Radio (NR) technology.

[0028] In one embodiment, base station 114a and WTRU 102a, 102b, 102c may implement multiple radio access technologies. For example, base station 114a and WTRU 102a, 102b, 102c may implement LTE radio access and NR radio access together, for example, using the dual connectivity (DC) principle. Thus, the air interface utilized by WTRU 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions sent to / from multiple types of base stations (e.g., eNB and gNB).

[0029] In other embodiments, base stations 114a and WTRUs 102a, 102b, and 102c may implement wireless technologies such as IEEE 802.11 (i.e., Wireless Fidelity, WiFi), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access, WiMAX), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), and GSM EDGE (GERAN).

[0030] The base station 114b in Figure 1A may be, for example, a wireless router, home node B, home e-node B, or access point, and may utilize any suitable RAT to facilitate wireless connectivity in localized areas such as businesses, homes, vehicles, campuses, industrial facilities, aerial corridors (for use by drones, for example), roads, etc. In one embodiment, the base station 114b and WTRU 102c, 102d may establish a wireless local area network (WLAN) by implementing wireless technologies such as IEEE 802.11. In another embodiment, the base station 114b and WTRU 102c, 102d may establish a wireless personal area network (WPAN) by implementing wireless technologies such as IEEE 802.15. In yet another embodiment, the base station 114b and WTRU 102c, 102d may establish a picocell or femtocell using a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.). As shown in Figure 1A, base station 114b may have a direct connection to the internet 110. Therefore, base station 114b may not need to access the internet 110 via CN106 / 115.

[0031] RAN104 / 113 can communicate with CN106 / 115, which may be any type of network configured to provide voice, data, applications, and / or Voice over Internet Protocol (VoIP) services to one or more WTRU102a, 102b, 102c, and 102d. The data may have various quality of service (QoS) requirements, such as different throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, and mobility requirements. CN106 / 115 may provide call control, billing services, mobile location-based services, prepaid calls, internet connectivity, video distribution, etc., and / or implement high-level security functions such as user authentication. Although not shown in Figure 1A, it will be understood that RAN104 / 113 and / or CN106 / 115 may communicate directly or indirectly with other RANs employing the same or different RAT as RAN104 / 113. For example, in addition to being connected to RAN104 / 113 which can utilize NR radio technology, CN106 / 115 can also communicate with another RAN (not shown) using GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0032] CN106 / 115 may also function as a gateway for WTRU102a, 102b, 102c, 102d to access PSTN108, the Internet 110, and / or other networks 112. PSTN108 may include a circuit-switched telephone network providing plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices, which use common communication protocols such as the transmission control protocol (TCP), the user datagram protocol (UDP), and / or the Internet protocol (IP) of the TCP / IP Internet Protocol suite. Network 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, network 112 may include another CN connected to one or more RANs, which may use the same RAT as RAN104 / 113 or a different RAT.

[0033] Some or all of the WTRUs 102a, 102b, 102c, and 102d in the communication system 100 may include multimode functionality (for example, WTRUs 102a, 102b, 102c, and 102d may include multiple transceivers for communicating with different radio networks via different radio links). For example, WTRU 102c shown in Figure 1A may be configured to communicate with base station 114a, which may employ cellular-based radio technology, and base station 114b, which may employ IEEE 802 radio technology.

[0034] Figure 1B is a system diagram illustrating an exemplary WTRU 102. As shown in Figure 1B, the WTRU 102 may include, among other things, a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power supply 134, a global positioning system (GPS) chipset 136, and / or other peripherals 138. It will be understood that the WTRU 102 may include any partial combination of the aforementioned elements while maintaining consistency with one embodiment.

[0035] The processor 118 may be a general-purpose processor, a dedicated processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) circuit, any other type of integrated circuit (IC), a state machine, etc. The processor 118 may perform signal coding, data processing, power control, input / output processing, and / or any other functions that enable the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to a transceiver 120 which can be coupled to a transmit / receive element 122. Figure 1B depicts the processor 118 and the transceiver 120 as separate components, but it will be understood that the processor 118 and the transceiver 120 can be integrated together in an electronic package or chip.

[0036] The transmit / receive element 122 may be configured to transmit or receive signals to and from a base station (e.g., base station 114a) via the air interface 116. For example, in one embodiment, the transmit / receive element 122 may be an antenna configured to transmit and / or receive RF signals. In one embodiment, the transmit / receive element 122 may be an emitter / detector configured to transmit and / or receive, for example, IR signals, UV signals, or visible light signals. In yet another embodiment, the transmit / receive element 122 may be configured to transmit and / or receive both RF signals and optical signals. It will be understood that the transmit / receive element 122 may be configured to transmit and / or receive any combination of radio signals.

[0037] Although the transmit / receive element 122 is depicted as a single element in Figure 1B, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for sending and receiving radio signals via the air interface 116.

[0038] The transceiver 120 may be configured to modulate the signal transmitted by the transmit / receive element 122 and demodulate the signal received by the transmit / receive element 122. As described above, the WTRU 102 may have multimode capabilities. Therefore, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11.

[0039] The processor 118 of the WTRU102 may be coupled to a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light-emitting diode (OLED) display unit) and may receive user input from these. The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. In addition, the processor 118 may access information from any suitable type of memory, such as non-removable memory 130 and / or removable memory 132, and store data in such memory. The non-removable memory 130 may include random-access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, and the like. In other embodiments, the processor 118 may access information from memory not physically located on the WTRU 102, such as on a server or home computer (not shown), and store data in that memory.

[0040] The processor 118 may be configured to receive power from the power supply 134 and distribute and / or control power to other components in the WTRU 102. The power supply 134 may be any suitable device for supplying power to the WTRU 102. For example, the power supply 134 may include one or more dry cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0041] The processor 118 may also be coupled to a GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to, or instead of, the information from the GPS chipset 136, the WTRU 102 may determine its location based on receiving location information from base stations (e.g., base stations 114a, 114b) via the air interface 116 and / or based on the timing of signals received from two or more nearby base stations. It will be understood that the WTRU 102 may acquire location information by any preferred location determination method while maintaining consistency with one embodiment.

[0042] The processor 118 may be further coupled to other peripherals 138, which may include one or more software and / or hardware modules that provide additional features, functions, and / or wired or wireless connectivity. For example, peripherals 138 may include an accelerometer, an electronic compass, a satellite transceiver, a digital camera (for photos and / or videos), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands-free headset, a Bluetooth® module, a frequency modulated (FM) radio unit, a digital music player, a media player, a video game player module, an internet browser, a virtual reality and / or augmented reality (VR / AR) device, an activity tracker, and the like. The peripheral device 138 may include one or more sensors, which may be one or more of the following: gyroscope, accelerometer, Hall effect sensor, magnetometer, compass sensor, proximity sensor, temperature sensor, time sensor, geolocation sensor, altimeter, light sensor, touch sensor, magnetometer, barometer, gesture sensor, biometric sensor, and / or humidity sensor.

[0043] WTRU102 may include a full-duplex radio in which the transmission and reception of some or all of the signals associated with specific subframes for both UL (e.g., for transmission) and downlink (e.g., for reception) may be in parallel and / or simultaneous. The full-duplex radio may include an interference management unit 139 for reducing and / or substantially eliminating self-interference via either hardware (e.g., chokes) or signal processing via a processor (e.g., via a separate processor (not shown) or processor 118). In one embodiment, WRTU102 may include a half-duplex radio for the transmission and reception of any of the signals (e.g., associated with specific subframes for either UL (e.g., for transmission) or downlink (e.g., for reception)).

[0044] Figure 1C is a system diagram illustrating RAN104 and CN106 according to one embodiment. As described above, RAN104 may employ E-UTRA radio technology to communicate with WTRU102a, 102b, and 102c via the air interface 116. RAN104 may also communicate with CN106.

[0045] RAN104 may include e-nodes B160a, 160b, and 160c, but it will be understood that RAN104 may include any number of e-nodes B while maintaining consistency with one embodiment. Each of e-nodes B160a, 160b, and 160c may include one or more transceivers for communicating with WTRU102a, 102b, and 102c via the air interface 116. In one embodiment, e-nodes B160a, 160b, and 160c may implement MIMO technology. Thus, e-node B160a may, for example, use multiple antennas to transmit radio signals to and / or receive radio signals from WTRU102a.

[0046] Each of the e-nodes B160a, 160b, and 160c may be associated with a specific cell (not shown) and may be configured to handle wireless resource management decisions, handover decisions, user scheduling in UL and / or DL, etc. As shown in Figure 1C, the e-nodes B160a, 160b, and 160c may communicate with each other via the X2 interface.

[0047] The CN106 shown in Figure 1C may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. Although each of the aforementioned elements is depicted as part of CN106, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0048] The MME162 can be connected to each of the e-nodes B162a, 162b, and 162c in RAN104 via the S1 interface and can function as a control node. For example, the MME162 may perform roles such as authenticating users of WTRU102a, 102b, and 102c, activating / deactivating bearers, and selecting a specific serving gateway during the initial attachment of WTRU102a, 102b, and 102c. The MME162 may provide control plane functionality for switching between RAN104 and other RANs (not shown) employing other radio technologies such as GSM and / or WCDMA.

[0049] The SGW164 can be connected to each of the e-nodes B160a, 160b, and 160c in RAN104 via the S1 interface. The SGW164 can generally route and forward user data packets to and from WTRU102a, 102b, and 102c. The SGW164 can perform other functions, such as anchoring the user plane during e-node B handovers, triggering paging when DL data is available to WTRU102a, 102b, and 102c, and managing and remembering the context of WTRU102a, 102b, and 102c.

[0050] SGW164 may be connected to PGW166, which may provide WTRU102a, 102b, and 102c with access to a packet-switched network such as the Internet 110 to facilitate communication between WTRU102a, 102b, and 102c and IP-enabled devices.

[0051] CN106 can facilitate communication with other networks. For example, CN106 can provide WTRU102a, 102b, and 102c with access to a circuit-switched network such as PSTN108 to facilitate communication between WTRU102a, 102b, and 102c and conventional terrestrial line communication devices. For example, CN106 may include, or communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that functions as an interface between CN106 and PSTN108. In addition, CN106 may provide WTRU102a, 102b, and 102c with access to another network 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0052] Although the WTRU is described as a wireless terminal in Figures 1A to 1D, in certain representative embodiments, such a terminal is intended to be able to use a wired communication interface with a communication network (for example, temporarily or permanently).

[0053] In a typical embodiment, the other network 112 may be a WLAN.

[0054] A WLAN in Infrastructure Basic Service Set (BSS) mode may have access points (APs) of the BSS and one or more stations (STAs) associated with the APs. APs may have access to or interfaces with other types of wired / wireless networks that carry traffic entering and / or leaving the Distribution System (DS) or BSS. Traffic originating outside the BSS and destined for an STA may reach and be delivered to the STA via an AP. Traffic originating from an STA and destined for an outside BSS destination may be sent to the AP so that it is delivered to its respective destination. Traffic between STAs within the BSS may be sent, for example, via an AP, where the source STA can send traffic to the AP, and the AP can deliver the traffic to the destination STA. Traffic between STAs within the BSS may be considered and / or referred to as peer-to-peer traffic. Peer-to-peer traffic may be sent between the source STA and the destination STA (for example, directly between them) using a direct link setup (DLS). In certain representative embodiments, the DLS may use 802.11e DLS or 802.11z tunneled DLS (TDLS). A WLAN using Independent BSS (IBSS) mode may not have APs, and STAs within or using IBSS (e.g., all STAs) may communicate directly with one another. The IBSS mode of communication may be referred to herein as “ad hoc” communication mode.

[0055] When using the 802.11ac infrastructure operating mode or a similar operating mode, an AP may transmit beacons on a fixed channel, such as the primary channel. The primary channel may be of a fixed width (e.g., a 20 MHz bandwidth) or a width dynamically set via signaling. The primary channel may be the operating channel of the BSS, but may be used by an STA to establish a connection with the AP. In a particular representative embodiment, for example, in an 802.11 system, Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA) may be implemented. In the case of CSMA / CA, an STA, including the AP (e.g., all STAs), may sense the primary channel. If the primary channel is sensed / detected and / or determined to be busy by a particular STA, that STA may be backed off. A single STA (e.g., only one station) may transmit at any given time in a given BSS.

[0056] High-throughput (HT) STAs may use a 40 MHz wide channel for communication, which may be formed, for example, through a combination of a primary 20 MHz channel and adjacent or non-adjacent 20 MHz channels.

[0057] Very High Throughput (VHT) STAs can support channels with widths of 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz. 40 MHz and / or 80 MHz channels can be formed by combining multiple adjacent 20 MHz channels. 160 MHz channels can be formed by combining eight consecutive 20 MHz channels, or by combining two non-adjacent 80 MHz channels, which may be referred to as an 80+80 configuration. In the 80+80 configuration, after channel coding, the data can pass through a segment parser that can split the data into two streams. Inverse Fast Fourier Transform (IFFT) processing and time-domain processing can be performed separately for each stream. The streams may be mapped to two 80 MHz channels, and the data can be transmitted by a transmitting STA. At the receiver of the receiving STA, the operation described above for the 80+80 configuration may be reversed, and the combined data may be sent to Medium Access Control (MAC).

[0058] Sub-1 GHz operating modes are supported by 802.11af and 802.11ah. Channel operating bandwidth and carrier are reduced in 802.11af and 802.11ah compared to those used in 802.11n and 802.11ac. 802.11af supports bandwidths of 5 MHz, 10 MHz, and 20 MHz in the TV White Space (TVWS) spectrum, while 802.11ah supports bandwidths of 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz using the non-TVWS spectrum. According to a typical embodiment, 802.11ah may support meter-type control / machine-type communications, such as MTC devices within a macro communication range area. MTC devices may have limited performance, including certain performance characteristics, e.g., support for certain and / or limited bandwidths (e.g., supporting only these). MTC devices may include batteries with battery life exceeding a threshold (e.g., to maintain very long battery life).

[0059] A WLAN system capable of supporting multiple channels and channel bandwidths such as 802.11n, 802.11ac, 802.11af, and 802.11ah includes a channel that can be designated as the primary channel. The primary channel may have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and / or limited by an STA from among all STAs operating in a BSS that support the minimum bandwidth operating mode. In an 802.11ah embodiment, the primary channel may be 1 MHz wide for an STA (e.g., an MTC type device) that supports (e.g., only) the 1 MHz mode, even if the AP and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and / or other channel bandwidth operating modes. Carrier sensing and / or Network Allocation Vector (NAV) settings may depend on the status of the primary channel. For example, if the primary channel is operational due to an STA (which only supports 1MHz operating mode) transmitting to the AP, the entire available frequency band may be considered operational, even though a large portion of the frequency band remains idle and could potentially be available.

[0060] In the United States, the available frequency band that can be used by 802.11ah is 902MHz to 928MHz. In South Korea, the available frequency band is 917.5MHz to 923.5MHz. In Japan, the available frequency band is 916.5MHz to 927.5MHz. The total bandwidth available for 802.11ah is 6MHz to 26MHz, depending on the country code.

[0061] Figure 1D is a system diagram illustrating RAN113 and CN115 according to one embodiment. As described above, RAN113 may employ NR radio technology to communicate with WTRU102a, 102b, and 102c via the air interface 116. RAN113 may also communicate with CN115.

[0062] RAN113 may include gNB180a, 180b, and 180c, but it will be understood that RAN113 may include any number of gNBs while maintaining consistency with one embodiment. Each of gNB180a, 180b, and 180c may include one or more transceivers for communicating with WTRU102a, 102b, and 102c via the air interface 116. In one embodiment, gNB180a, 180b, and 180c may implement MIMO technology. For example, gNB180a and 108b may use beamforming to transmit signals to and / or receive signals from gNB180a, 180b, and 180c. Thus, gNB180a may, for example, use multiple antennas to transmit and / or receive radio signals to and from WTRU102a. In one embodiment, gNB180a, 180b, and 180c may implement carrier aggregation technology. For example, gNB180a may transmit multiple elemental carriers to WTRU102a (not shown). A subset of these elemental carriers may be on the unlicensed spectrum, while the remaining elemental carriers may be on the licensed spectrum. In one embodiment, gNB180a, 180b, and 180c may implement coordinated multi-point (CoMP) technology. For example, WTRU102a may receive coordinated transmissions from gNB180a and gNB180b (and / or gNB180c).

[0063] WTRU102a, 102b, and 102c may communicate with gNB180a, 180b, and 180c using transmissions associated with scalable neurology. For example, OFDM symbol intervals and / or OFDM subcarrier intervals may vary for different transmissions, different cells, and / or different portions of the radio transmission spectrum. WTRU102a, 102b, and 102c may communicate with gNB180a, 180b, and 180c using subframes or transmission time intervals (TTIs) of varying or scalable lengths (e.g., containing varying numbers of OFDM symbols and / or having varying absolute time durations).

[0064] gNB180a, 180b, and 180c can be configured to communicate with WTRU102a, 102b, and 102c in standalone and / or non-standalone configurations. In a standalone configuration, WTRU102a, 102b, and 102c can communicate with gNB180a, 180b, and 180c without accessing other RANs (e.g., e-nodes B160a, 160b, and 160c). In a standalone configuration, WTRU102a, 102b, and 102c can utilize one or more of gNB180a, 180b, and 180c as mobility anchor points. In a standalone configuration, WTRU102a, 102b, and 102c can communicate with gNB180a, 180b, and 180c using signals in unauthorized bands. In a non-standalone configuration, WTRU102a, 102b, and 102c can communicate with and connect to gNB180a, 180b, and 180c, while also communicating with and connecting to other RANs such as enodes B160a, 160b, and 160c. For example, WTRU102a, 102b, and 102c can implement DC principles for substantially simultaneous communication with one or more gNB180a, 180b, and 180c and one or more enodes B160a, 160b, and 160c. In a non-standalone configuration, e-nodes B160a, 160b, and 160c can function as mobility anchors for WTRU102a, 102b, and 102c, and gNB180a, 180b, and 180c can provide additional coverage and / or throughput to service WTRU102a, 102b, and 102c.

[0065] Each of the gNB180a, 180b, and 180c may be associated with a specific cell (not shown) and may be configured to handle wireless resource management decisions, handover decisions, user scheduling in UL and / or DL, support for network slicing, dual connectivity, interworking between NR and E-UTRA, routing of user plane data to User Plane Functions (UPFs) 184a and 184b, routing of control plane information to Access and Mobility Management Functions (AMFs) 182a and 182b, and so on. As shown in Figure 1D, the gNB180a, 180b, and 180c may communicate with each other via the Xn interface.

[0066] The CN115 shown in Figure 1D may include at least one AMF182a, 182b, at least one UPF184a, 184b, at least one Session Management Function (SMF)183a, 183b, and optionally a Data Network (DN)185a, 185b. Although each of the aforementioned elements is depicted as part of the CN115, it will be understood that any of these elements may be owned and / or operated by entities other than the CN operator.

[0067] AMF182a and 182b can be connected to one or more gNB180a, 180b, and 180c in RAN113 via the N2 interface and can function as control nodes. For example, AMF182a and 182b may perform roles such as user authentication for WTRU102a, 102b, and 102c, support network slicing (e.g., handling different PDU sessions with different requirements), selection of specific SMF183a and 183b, management of registration areas, termination of NAS signaling, and mobility management. Network slicing can be used by AMF182a and 182b to customize CN support for WTRU102a, 102b, and 102c based on the type of service utilizing WTRU102a, 102b, and 102c. For example, different network slices may be established for different use cases, such as services relying on ultra-reliable low latency (URLLC) access, services relying on enhanced massive mobile broadband (eMBB) access, and services for machine type communication (MTC) access. AMF162 may provide control plane functionality for exchange between RAN113 and other RANs (not shown) using other radio technologies such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies such as WiFi.

[0068] SMF183a and 183b can be connected to AMF182a and 182b in CN115 via the N11 interface. SMF183a and 183b can also be connected to UPF184a and 184b in CN115 via the N4 interface. SMF183a and 183b can select and control UPF184a and 184b and configure the routing of traffic through UPF184a and 184b. SMF183a and 183b can perform other functions such as managing and allocating UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, and providing downlink data notifications. PDU session types can be IP-based, non-IP-based, Ethernet-based, etc.

[0069] UPF184a and 184b may be connected via the N3 interface to one or more gNB180a, 180b, and 180c in RAN113, thereby providing WTRU102a, 102b, and 102c with access to a packet-switched network such as the Internet 110 to facilitate communication between WTRU102a, 102b, and 102c and IP-enabled devices. UPF184 and 184b may perform other functions such as routing and forwarding packets, enforcing user plane policies, supporting multiple home PDU sessions, handling user plane QoS, buffering downlink packets, and providing mobility anchoring.

[0070] CN115 can facilitate communication with other networks. For example, CN115 may include, or communicate with, an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that functions as an interface between CN115 and PSTN108. In addition, CN115 may provide WTRU102a, 102b, 102c with access to another network 112, which may include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, WTRU102a, 102b, 102c may be connected to the local data network (DN) 185a, 185b via UPF184a, 184b through an N3 interface to UPF184a, 184b, and an N6 interface between UPF184a, 184b and DN185a, 185b.

[0071] In view of Figures 1A to 1D and their corresponding descriptions, one or more of the functions described herein with respect to one or more of the WTRU102a to d, base stations 114a and b, e-nodes-B160a to c, MME162, SGW164, PGW166, gNB180a to c, AMF182a to ab, UPF184a and b, SMF183a and b, DN185a and b, and / or any other devices described herein, may be implemented by one or more emulation devices (not shown). An emulation device may be one or more devices configured to emulate one or more of the functions described herein. For example, an emulation device may be used to test other devices and / or simulate network and / or WTRU functions.

[0072] Emulation devices may be designed to implement testing of one or more other devices in a laboratory and / or carrier network environment. For example, one or more emulation devices may perform one or more or all functions while fully or partially implemented and / or deployed as part of a wired and / or wireless network to test other devices in a communications network. One or more emulation devices may perform one or more or all functions while temporarily implemented / deployed as part of a wired and / or wireless network. Emulation devices may be directly coupled to another device for testing purposes and / or may perform testing using terrestrial wireless communication.

[0073] One or more emulation devices may perform one or more functions, including all of the above, while not implemented / deployed as part of a wired and / or wireless communication network. For example, an emulation device may be used in a test laboratory test scenario, and / or in a wired and / or wireless communication network that is not deployed (e.g., for testing purposes), to implement testing of one or more components. One or more emulation devices may be test equipment. Direct RF coupling and / or wireless communication via RF circuitry (e.g., which may include one or more antennas) may be used by the emulation device to transmit and / or receive data.

[0074] Discovery transmissions may be performed. A WTRU may support and / or request one or more relay services. A WTRU may perform discovery-relay-service message transmissions. A WTRU may receive (pre)configurations for discovery-relay-service transmissions. A WTRU may indicate its supported relay service(s) capabilities to the network. A WTRU may receive instructions from the network indicating the type of relay (e.g., what type of relay it should be). A WTRU may request resources for discovery-relay-service transmissions. A WTRU may perform discovery-relay-service message transmissions. A WTRU may determine which discovery-relay-service message to send. A WTRU may determine the quality of service associated with a discovery-relay-service message. A WTRU may determine resource pools for sending discovery-relay-service messages. A WTRU may determine discovery-relay-service parameters. A WTRU may determine information to include in a discovery message.

[0075] Relay selection may be performed. The WTRU may trigger relay selection. The WTRU may determine which relay to (re)select. The WTRU may determine whether relay reselection should be performed and / or whether the set of relays detected should be reported to the network.

[0076] A WTRU may report a set of discovered remote WTRUs and / or a set of discovered relays. A WTRU may request resources for a discover-relay-service transmission. A WTRU may receive instructions to send a discover-relay-service message. A WTRU may trigger cell reselection. A WTRU may determine which cells should be prioritized / reported.

[0077] In the example, a WTRU (e.g., a relay WTRU) may determine which discover-relay-service message to send, one or more discover-transmit parameters, and one or more resource pools to send the discover-message to, based on the Uu reference signal received power (RSRP), relay load, and / or WTRU relay capability.

[0078] For example, a WTRU may be (pre)configured with conditions for sending multipath and / or singlepath discovery messages (e.g., via a dedicated RRC or SIB). Alternatively or additionally, a WTRU may receive conditions for sending multipath and / or singlepath discovery messages (e.g., via a dedicated RRC or SIB). A discovery message may include one or more of the following: Uu RSRP ranges for single-path discovery (e.g., minimum and maximum Uu RSRP), (e.g., different) minimum Uu RSRPs for multipath discovery, relay capabilities (e.g., may include support for single-path and / or multipath relays), and / or quality of service (QoS) (e.g., priority), and one or more of the transmission resource pools for one or more (e.g., each) types of discovery messages. A WTRU may determine which type of discovery message to send based on one or more of its measured Uu RSRP, relay load, and WTRU capabilities to support multipath and / or single-path relays. In the example, a WTRU may allow sending single-path discoveries (e.g., only) in high-load cases (e.g., network expansion may be prioritized). A WTRU may select a resource pool for sending discovery messages based on the discovery type. A WTRU may use the (pre)configured QoS for discovery messages to determine the transmission parameters for discovery messages. A WTRU may include the discovery type (e.g., single-path and / or multipath), Uu RSRP (for example, for a remote WTRU to perform relay selection) and / or one or more of the QoS of the discovery message within the discovery message may be indicated. The WTRU may perform discovery transmission.

[0079] In the example, a WTRU (e.g., a remote WTRU) may determine whether to transmit single-path discovery and / or multipath discovery based on one or more of the following: its measured Uu RSRP, receipt of SLRB / LCH configuration for multipath, and / or incoming data from a set of SLRB / LCH into a buffer. When transmitting multipath discovery, the WTRU may select / report (e.g., to the gNB) a set of relays that support multipath and have appropriate Uu RSRP.

[0080] For example, a WTRU (e.g., a remote WTRU) may be (pre) configured with conditions for sending discovery messages, or may receive conditions (e.g., via a dedicated RRC or SIB). A discovery message may include one or more of the following: a maximum Uu RSRP for single-path discovery, a range of Uu RSRPs for multipath discovery (e.g., minimum and (e.g., different) maximum Uu RSRPs), a set of SLRB / LCHs to trigger multipath discovery, and / or the minimum Uu RSRP for each relay per SLRB / LCH. When an SLRB / LCH configuration is received and / or SLRB / LCH data arrives that satisfies the configured conditions for multipath relays, the WTRU may trigger a discovery transmission, perform relay response reception, and / or perform relay selection, or select a set of relays to advertise to the network that satisfy the following conditions: supporting multipath, supporting established SLRB / LCHs, and the relay's Uu RSRP is higher than a threshold that can be obtained based on the remote WTRU's SLRB / LCH. For example, if the Uu threshold for single-path transmission is not met but the threshold for multipath discovery is met, the WTRU may, upon receiving an SLRB / LCH configuration and / or when SLRB / LCH data arrives that meets the configured conditions for multipath relay, trigger a discovery transmission, perform a relay response reception and / or perform a relay selection, or select a set of relays to advertise to the network that meet the following conditions: support multipath, support established SLRB / LCH, and the relay's Uu RSRP is higher than the threshold that may be obtained based on the remote WTRU's SLRB / LCH.

[0081] A relay WTRU may determine which set of discovered remote WTRUs should be reported to the network. Additionally or alternatively, a WTRU (e.g., a relay WTRU) may determine which set of discovered relays should be reported to the network. A relay WTRU may indicate (e.g., send) information in its discovery message. A remote WTRU may indicate (e.g., send) its Uu connection status in its discovery service message. A WTRU may decide to send a discovery-relay-service message. A WTRU may determine whether a cell should support one or more relay services. A WTRU may determine whether to send a discovery-relay-service message based on instructions from the cell. A WTRU may determine whether to respond to (e.g., send) a remote WTRU. A WTRU may determine its load.

[0082] A WTRU (e.g., a first WTRU) may monitor one or more discovery messages. These discovery messages may be from one or more second WTRUs. The WTRU may, for example, determine a set of one or more second WTRUs based on the discovery messages. The WTRU may report this set of second WTRUs to the network, for example. The set of one or more second WTRUs may be based on their support type. The support type may include one or more of single-path and multi-path services. The WTRU may compare the reference signal received power (RSRP) of a second WTRU to a threshold. The WTRU may determine the support type based on the comparison of the second WTRU RSRP with the threshold. For example, if the second WTRU RSRP is below the threshold, the WTRU may determine that the support type is single-path service. In another example, if the second WTRU RSRP is below the threshold, the WTRU may determine that the support type is single-path service. The WTRU may determine its support type based on the connectivity status of the second WTRU. The WTRU may compare the quality of service (QoS) of the second WTRU to a threshold.

[0083] A WTRU (e.g., a relay WTRU) may receive configuration information. This configuration information may include one or more parameters. These one or more parameters may be necessary for the WTRU to operate as a mobile relay between networks. Additionally or alternatively, the parameters may include a first reference signal power (RSRP) threshold and / or a second RSRP threshold.

[0084] The WTRU may perform RSRP measurements. For example, the WTRU may perform RSRP measurements on a serving cell to determine the RSRP value. The WTRU may determine whether it supports one or more of single-path and multi-path operations. For example, the WTRU may determine whether it supports one or more of single-path and multi-path operations in a sidelink discovery message based on the RSRP value. The WTRU may indicate support for multi-path relay operations based on the RSRP value meeting a second RSRP threshold. Additionally or alternatively, the WTRU may indicate support for single-path relay operations based on the RSRP value meeting a first RSRP threshold. The WTRU may send a sidelink discovery message indicating support for one or more of single-path and multi-path relay operations. For example, the WTRU may send a sidelink discovery message indicating support for one or more of single-path and multi-path relay operations based on the RSRP value.

[0085] The parameters may include the relay load range. WTRU may indicate support for multipath relay operation based on, for example, whether the current relay load of the WTRU is below the relay load range. The parameters may include an indication for a first resource pool and / or a second resource pool. The first resource pool may be, for example, a resource pool for sending a first sidelink discovery message indicating support for single-path relay operation. The second resource pool may be, for example, a resource pool for sending a second sidelink discovery message indicating support for multipath relay operation. The sidelink discovery message may indicate an RSRP value. WTRU may indicate support for single-path relay operation when the RSRP value is greater than or equal to a first RSRP threshold. Additionally or alternatively, WTRU may indicate support for single-path relay operation when the RSRP value is less than a second RSRP threshold.

[0086] A WTRU may indicate support for multipath relay operation when the RSRP value is equal to or greater than a second RSRP threshold. A WTRU may, for example, send a report to the network based on the RSRP value. The report may indicate one or more second WTRUs. For example, the report may indicate one or more second WTRUs requesting single-path relay operation when the RSRP value meets the first RSRP threshold. Additionally or alternatively, the report may indicate that one or more second WTRUs are requesting multipath relay operation when the RSRP value meets the second RSRP threshold.

[0087] Figure 2 illustrates an exemplary system 200 illustrating a user-plane radio protocol stack for a Layer 2 evolved WTRU-to-network relay (e.g., PC5). For example, Figure 2 illustrates a remote WTRU 202, an L2 relay WTRU 204, an eNB 206, and a core network (CN) 208. The PC5 interface between the remote WTRU 202 and the L2 relay WTRU 204 may be associated with (e.g., lower) layers, including, for example, one or more of the physical layer (PHY), MAC layer, and radio link control (RLC) layer. The Uu interface between the L2 relay WTRU 204 and the eNB 206 may be associated with (e.g., lower) layers, including, for example, one or more of the adaptation layer, physical layer (PHY), MAC layer, and radio link control (RLC) layer. The interface between eNB206 and CN208 (e.g., S1-U / S5 / S8) can be associated with L1 / L2.

[0088] Figure 3 illustrates an exemplary system 300 illustrating a control plane radio protocol stack for an L2 evolved WTRU-to-network relay (e.g., PC5). For example, Figure 3 illustrates a remote WTRU 302, an L2 relay WTRU 304, an eNB 306, and a core network (CN) 308. The PC5 interface between the remote WTRU 302 and the L2 relay WTRU 304 may be associated with a (e.g., lower) layer, including, for example, one or more of the Physical Layer (PHY), MAC layer, and Radio Link Control (RLC) layer. The Uu interface between the L2 relay WTRU 304 and the eNB 306 may be associated with a (e.g., lower) layer, including, for example, one or more of the Adaptation Layer, Physical Layer (PHY), MAC layer, and Radio Link Control (RLC) layer. The interface between the eNB 306 and the CN 308 (e.g., S1-MME) may be associated with L1 / L2.

[0089] The ProSe WTRU-to-network relay can perform relaying (for example, it can be used as a relay). For example, the ProSe WTRU-to-network relay can be used as a relay to extend network coverage to out-of-coverage WTRUs by using PC5(D2D) between the out-of-coverage WTRU and the WTRU-to-network relay.

[0090] A ProSe WTRU-to-Network relay may provide forwarding functionality. For example, a ProSe WTRU-to-Network relay may provide general-purpose L3 forwarding functionality. This forwarding functionality may relay any type of IP traffic between the remote WTRU and the network. One-to-one and one-to-many sidelink communications may be sent between the remote WTRU and the ProSe WTRU-to-Network relay. For both the remote WTRU and the relay WTRU, single-carrier (e.g., public safety ProSe carrier) operation (e.g., only) may be supported (e.g., Uu and PC5 must be the same carrier for the relay / remote WTRU). The remote WTRU may be authorized. For example, the remote WTRU may be authorized by one or more higher layers. Alternatively or additionally, the remote WTRU may reside within the coverage of the public safety ProSe carrier and / or outside the coverage on any supported carrier, including the public safety ProSe carrier for WTRU-to-Network relay discovery, (re)selection, and / or communications. ProSe WTRU-inter-network relays may (for example, always) be within the coverage of EUTRAN. ProSe WTRU-inter-network relays and remote WTRUs may perform sidelink communication and / or sidelink discovery as described in one or more specifications.

[0091] Relay selection may be performed for WTRU-to-network relays. For example, relay selection / re-selection may be performed for ProSe WTRU-to-network relays. Relay selection may be based on one or more of the AS Layer Quality Measurement (RSRP) and / or higher-layer criteria. For example, an eNB may control whether a WTRU can be a ProSe WTRU-to-network relay. ProSe WTRU-to-network relay operation may be supported in a cell. ProSe WTRU-to-network relay operation may be supported in a cell if the eNB broadcasts information associated with the ProSe WTRU-to-network relay operation (e.g., arbitrary information). The eNB may provide transmit resources. Transmit resources may be transmit resources for ProSe WTRU-to-network relay discovery. Additionally or alternatively, transmit resources may use broadcast signaling for the RRC_IDLE state and / or dedicated signaling for the RRC_CONNECTED state, and / or receive resources for ProSe WTRU-to-network relay discovery using broadcast signaling.

[0092] The eNB may broadcast minimum and / or maximum Uu Link Quality (RSRP) thresholds. These minimum and / or maximum Uu Link Quality (RSRP) thresholds may be thresholds that a ProSe WTRU-to-Network relay can satisfy before initiating the WTRU-to-Network relay discovery procedure. The WTRU may use the thresholds to autonomously start and / or stop the WTRU-to-Network relay discovery procedure. For example, in RRC_IDLE, when the eNB broadcasts the transmit resource pool, the WTRU may use the thresholds to autonomously start or stop the WTRU-to-Network relay discovery procedure. The WTRU may use the thresholds to determine whether the WTRU can indicate its relay WTRU status (e.g., that the WTRU is a relay WTRU) to the eNB and / or whether it can (e.g., wants to) initiate ProSe WTRU-to-Network relay discovery. For example, in RRC_CONNECTED, the WTRU may use thresholds to determine whether it can indicate its relay WTRU status (e.g., that the WTRU is a relay WTRU) to the eNB and / or whether it can (e.g., wants to) initiate ProSe WTRU-to-network relay discovery. The WTRU may, for example, take these (e.g., broadcast) thresholds into consideration and initiate a request for ProSe WTRU-to-network relay discovery resources via dedicated signaling. For example, if the eNB does not broadcast a transmit resource pool for ProSe-WTRU-to-network relay discovery, the WTRU may, for example, take these broadcast thresholds into consideration and initiate a request for ProSe-WTRU-to-network relay discovery resources via dedicated signaling.

[0093] A ProSe WTRU-Network relay may perform sidelink communication (e.g., sidelink communication for ProSe WTRU-Network relay operation). For example, a ProSe WTRU-Network relay may perform sidelink communication for ProSe WTRU-Network relay operation in RRC_CONNECTED. A ProSe WTRU-Network relay may indicate to the eNB that it is a ProSe WTRU-Network relay and can (e.g., intends to) perform ProSe WTRU-Network relay sidelink communication. After receiving a Layer 2 link establishment request and / or TMGI monitoring request (e.g., a higher layer message) from a remote WTRU, a ProSe WTRU-Network relay may indicate to the eNB that it is a ProSe WTRU-Network relay and / or can (e.g., intends to) perform ProSe WTRU-Network relay sidelink communication. The eNB may provide resources for ProSe WTRU-Network relay communication.

[0094] A remote WTRU may decide when to begin monitoring for ProSe WTRU-Inter-Network Relay Discovery. A remote WTRU may send a ProSe WTRU-Inter-Network Relay Discovery request message. For example, a remote WTRU may send a ProSe WTRU-Inter-Network Relay Discovery request message while in RRC_IDLE and / or RRC_CONNECTED (depending on the configuration of resources for ProSe WTRU-Inter-Network Relay Discovery). The eNB may broadcast thresholds. Thresholds may be used by remote WTRUs. For example, thresholds may be used by a remote WTRU to determine whether it can send a ProSe WTRU-Inter-Network Relay Discovery request message and / or connect to or communicate with a ProSe WTRU-Inter-Network Relay WTRU. For example, a remote WTRU may use a broadcasted threshold to determine whether it can indicate to the eNB that it is a remote WTRU and / or can (or wishes to) participate in ProSe WTRU-Inter-Network Relay Discovery and / or communication. Additionally or alternatively, a remote WTRU may be an RRC_CONNECTED remote WTRU. An eNB may provide transmit resources using broadcast and / or dedicated signaling and / or receive resources. For example, an eNB may provide transmit resources using broadcast signaling for ProSe WTRU-inter-network relay operation. A remote WTRU may cease using ProSe WTRU-inter-network relay discovery and / or communication resources. For example, a remote WTRU may cease using ProSe WTRU-inter-network relay discovery and communication resources when the RSRP exceeds a broadcasted threshold.

[0095] The (e.g., exact) time for traffic switching from Uu to PC5 and / or from PC5 to Uu may depend on the layer (e.g., the upper layer).

[0096] A remote WTRU may perform radio measurements on the PC5 interface. The remote WTRU may use radio measurements for ProSe WTRU-to-network relay selection and / or reselection (e.g., in conjunction with higher-layer criteria). A ProSe WTRU-to-network relay may be selected (e.g., deemed suitable with respect to the radio criteria). For example, a ProSe WTRU-to-network relay may be selected if the PC5 link quality exceeds a configured threshold (e.g., a pre-configured threshold or a threshold provided by the eNB) (e.g., deemed suitable with respect to the radio criteria). The remote WTRU may select a ProSe WTRU-to-network relay from among one or more (e.g., all) suitable ProSe WTRU-to-network relays that meets the higher-layer criteria and has the best PC5 link quality.

[0097] A remote WTRU may trigger a ProSe WTRU-to-network relay reselection. For example, a remote WTRU may trigger a ProSe WTRU-to-network relay reselection when one or more of the following occur: the current PC5 signal strength of the ProSe WTRU-to-network relay falls below a configured signal strength threshold, and / or the remote WTRU receives a Layer 2 link (L2) release message (e.g., an upper layer message) from the ProSe WTRU-to-network relay.

[0098] WTRU-to-network relays may be used for wearables. For example, WTRU-to-network relays for commercial use cases (e.g., WTRU-to-network relays tailored to wearables and / or IoT devices) may be used. A WTRU-to-network relay for wearables may be an L2 relay (unlike ProSe WTRU-to-network relays, which may use L3 (e.g., IP layer) relay techniques). A WTRU-to-network relay for wearables may use one or more of the protocol stacks, for example, illustrated in Figures 2 and / or 3. Figure 2 illustrates an exemplary user-plane radio protocol stack for an L2-evolved WTRU-to-network relay (PC5). Figure 3 illustrates an exemplary control-plane radio protocol stack for an L2-evolved WTRU-to-network relay (PC5).

[0099] A single-hop W2N relay may be used. In the discovery model, one or more (e.g., two) models may be used for discovery and / or relay (re)selection. For example, in the first model, the W2N relay may send an announcement message. In the second model, the remote WTRU may send a request message to another relay WTRU to request relay service. The W2N relay may respond to the request message from the remote WTRU.

[0100] W2N relays can be used to extend network coverage. A WTRU may be configured with a Uu RSRP range [min_Uu_RSRP, max_Uu_RSRP] to send, for example, an outgoing discovery message (e.g., an outgoing discovery message for discovery transmission). A WTRU may be permitted to send a discovery message if max_Uu_RSRP ≥ Uu and / or RSRP ≥ min_Uu_RSRP.

[0101] Multipath relays may be used. For example, in a multipath scenario, a WTRU (e.g., a remote WTRU) may be able to connect to the same gNB (e.g., simultaneously) using a direct path (e.g., via a Uu) and / or an indirect path (e.g., via a W2N relay). Multipath scenarios may be intended to improve system reliability and / or throughput.

[0102] In multipath scenarios, a WTRU that does not satisfy max_Uu_RSRP (e.g., a WTRU close to the cell center) (e.g., a relay WTRU) may not be a good candidate for a remote WTRU in a single path, but (e.g., nevertheless) may be a good W2N relay for a remote WTRU in a multipath. Furthermore, a relay may be able to support multipath (e.g., as a secondary leg rather than a primary leg) and / or support single path (e.g., a Rel17 relay). Therefore, conditions for discovery and / or relay selection may be considered. In the case of a remote WTRU, the conditions for discovery transmission (e.g., Uu RSRP < threshold) may not be applicable to multipath in some examples. New conditions related to the need to set up multipath (e.g., reliability and throughput) and / or the need to guarantee QoS of network services may be useful (e.g., may be required). Therefore, new discovery and relay discovery procedures and / or relay selection procedures may be designed to support multipath scenarios.

[0103] As described herein, WTRU can be (pre)configured with parameters. The (pre)configuration of parameters may be within a range (e.g., [a,b]) for performing a particular behavior. One omitted boundary (either a or b) from the (pre)configuration may be equivalent to the boundary being (pre) configured with the maximum or minimum attainable values ​​of the parameters.

[0104] In this specification, the statement that a WTRU is (pre)configured with ~ can be used interchangeably with the statement that a WTRU is pre-configured with parameters, and / or that a WTRU is configured with parameters (e.g., from gNB via a dedicated RRC or SIB).

[0105] In this specification, the terms relay selection and relay re-selection may be used interchangeably.

[0106] One or more of the solutions described herein may be described in relation to discovery-relay-service messages. Alternatively or in addition, the solutions described herein may be used for any discovery message or any other type of message (e.g., direct communication request (DCR) message) and / or may be applicable to such messages.

[0107] Discovery transmissions may be carried out as described herein. For example, a WTRU may support one or more relay services.

[0108] A WTRU (for example, a relay WTRU) may support one or more of the following relay services: single-path relay service, multi-path relay service, single-hop relay service, multi-hop relay service, Layer 2 (L2) relay service, and / or Layer 3 (L3) relay service.

[0109] A WTRU may support single-path relay services. For example, in a single-path relay service, a WTRU (e.g., a relay WTRU) may support relaying Uu traffic from a remote WTRU in the uplink and / or downlink direction. A WTRU may also support monitoring the paging of a remote WTRU. A WTRU may support receiving system information (SI) requests from a remote WTRU and / or forwarding those requests to the network. A WTRU may support forwarding SI information (e.g., SI requests) to a remote WTRU.

[0110] A WTRU may support multipath relay services. For example, in a multipath relay service, a WTRU (e.g., a relay WTRU) may support relaying Uu traffic from a remote WTRU in the uplink and / or downlink direction. A WTRU may not support monitoring paging from a remote WTRU. In some examples, a WTRU may not support receiving SI requests from a remote WTRU. In some examples, a WTRU may not support forwarding SIs for a remote WTRU.

[0111] A WTRU may support single-hop relay services. Alternatively or additionally, a WTRU may support direct relaying of data from source to destination. For example, a relay WTRU that supports single-hop relay services may also support direct relaying of data from source to destination. In some examples, a WTRU may not support relaying data to and / or from intermediate nodes. The source may be a gNB and / or another WTRU. Additionally or alternatively, the destination may be a gNB and / or another WTRU.

[0112] A WTRU may support multi-hop relay services. For example, a relay WTRU supporting multi-hop relay services may support relaying data from / to intermediate nodes. Additionally or alternatively, a WTRU may support relaying data directly from source to destination. The source may be a gNB and / or another WTRU. Additionally or alternatively, the destination may be a gNB and / or another WTRU.

[0113] A WTRU may support L2 relay services. For example, a relay WTRU supporting L2 relay services may support receiving configurations for relay data from the network. A relay WTRU may support one or more of the following: paging monitoring, receiving SI requests, and / or forwarding SI information to a remote WTRU.

[0114] In the example, a relay WTRU may support single-path relay services (e.g., only), multi-path relay services (e.g., only), or both single-path and multi-path relay services. A WTRU may support single-hop relay services (e.g., only) or multi-hop relay services. A WTRU that supports multi-hop relay services may, in addition to or as an alternative, support single-hop relay services. A WTRU may support being a W2W relay (e.g., only), a W2N relay (e.g., only), or both W2W and W2N relays for a remote WTRU.

[0115] A WTRU may request one or more relay services. For example, a WTRU (e.g., a remote WTRU) may support one or more of the following relay services: single-path relay service, multi-path relay service, single-hop relay service, multi-hop relay service, Layer 2 (L2) relay service, and / or Layer 3 (L3) relay service.

[0116] A WTRU may request a single-path relay service. For example, a remote WTRU requesting a single-path relay service may request the relay to forward Uu data from and to the gNB to and from the remote WTRU. A WTRU may request a relay service. A relay service request may include monitoring paging for the remote WTRU, receiving SI requests, and / or forwarding SI information.

[0117] A WTRU may request multipath relay services. For example, a remote WTRU requesting multipath relay services may request a relay WTRU to forward Uu data from / to a gNB to / from a remote WTRU. In some cases, a WTRU may not request one or more relay WTRUs to monitor paging, receiving SI requests, and / or forwarding SI information for the remote WTRU.

[0118] A WTRU may request single-hop relay services. For example, a remote WTRU may request connection to a WTRU-to-network (W2N) relay (e.g., in a discover-relay-service message). The W2N relay may connect directly to a gNB, for example. A remote WTRU may request single-hop relay services. For example, a remote WTRU may request connection to a WTRU-to-network (U2N) relay (e.g., in a discover-relay-service message). The WTRU-to-network relay may connect directly to a gNB. In some examples, a remote WTRU may request single-hop relay services to connect to a WTRU-to-WTRU (U2U) relay. The U2U relay may connect to another WTRU.

[0119] A WTRU may request a multi-hop relay service, which may enable the WTRU to connect to, for example, a WTRU-WTRU (W2W) relay. A W2W relay may connect to the network via a W2N relay. A WTRU may implicitly and / or explicitly indicate that it is requesting to connect to a W2W relay. For example, a WTRU may implicitly and / or explicitly indicate that it is requesting to connect to a W2W relay in a discover-relay-service message. A remote WTRU may request a multi-hop relay service, which may enable a WTRU (e.g., another WTRU) to connect to, for example, a U2U relay. A U2U relay may connect to the network via a WTRU-network (U2N) relay. Alternatively or additionally, a WTRU may send a discover-service message that implicitly and / or explicitly indicates that the WTRU is requesting to connect to a U2U relay. A remote WTRU may request relay services without requesting single-hop or multi-hop relay services. A WTRU may connect to one or more single-hop relay services and multi-hop relay services (for example, after requesting a relay service).

[0120] A WTRU may request relay services, whether single-hop or multi-hop. A WTRU may connect to single-hop relay and / or multi-hop relay services. A remote WTRU may request L2 relay services, for example, in a discover-relay-service message. A remote WTRU may receive (or expect to receive) an SLRB configuration for L2 relay services from a gNB and / or relay WTRU.

[0121] A WTRU may request L2 relay services in a discover-relay-service message. A WTRU may expect to receive an SLRB configuration for L2 relay services from a gNB and / or relay WTRU.

[0122] A WTRU may request L3 relay services in a discover-relay-service message. In some cases, a WTRU may not expect to receive an SLRB configuration for relay services from a gNB and / or relay WTRU.

[0123] A WTRU may perform the act of sending a Discover-Relay-Service message. For example, a WTRU (e.g., a relay WTRU) may send a Discover-Relay-Service message (e.g., a Discover-Relay-Service Announcement). A Discover-Relay-Service message may be used to provide a remote WTRU with one or more of the following relay services: single-path relay service, multi-path relay service, single-hop relay service, multi-hop relay service, Layer 2 relay service, and / or Layer 3 relay service. In another example, a WTRU (e.g., a remote WTRU) may send a Discover-Relay-Service message (e.g., a Discover-Relay-Service Request Message). A Discover-Relay-Service message may be used to request relay service from one or more relay WTRUs. The WTRU may, in addition or alternatively, request one or more of the following relay services from one or more relay WTRUs: single-path relay service, multi-path relay service, single-hop relay service, multi-hop relay service, Layer 2 relay service, and / or Layer 3 relay service. As described herein, discover-relay-service messages may be used for one or more of the discover-relay-service announcements, discover-relay-service requests, and / or discover-relay-service response messages.

[0124] Network-scheduled discover transmissions may be performed. A WTRU may receive (pre)configuration for discover-relay-service transmissions. A WTRU may be (pre)configured with one or more parameters and / or conditions for discover-relay-service transmissions. For example, a WTRU may receive configuration from the network via SIB and / or dedicated RRC messages. Additionally or alternatively, a WTRU may be pre-configured with the following parameters and / or conditions for discover-relay-service transmissions for one or more types of discover-relay-service messages: Uu RSRP, a resource pool and / or resource pool type for transmitting a certain type of discover-relay-service message, parameters for discover-relay-service transmissions, and / or one or more of the minimum Uu RSRP for relays and / or minimum SL-RSRP / SD-RSRP for SLRB / LCH.

[0125] The parameters and / or conditions for discover-relay-service transmission may include Uu RSRP. The parameters and / or conditions for discover-relay-service transmission may include Uu RSRP ranges for one or more (e.g., each) types of discover-relay-service messages, as described herein. For example, a WTRU (e.g., a relay WTRU) may be (pre-configured) with a minimum Uu RSRP to transmit multipath discover-relay-service messages. For example, a WTRU may transmit a multipath discover-relay-service message if the measured Uu RSRP is greater than a configured minimum Uu RSRP threshold (e.g., min_Uu_RSRP). In some scenarios, if the measured Uu RSRP is less than min_Uu_RSRP, the WTRU may not transmit a multipath discover-relay-service message. In another example, a WTRU (e.g., a remote WTRU) may be (pre-configured) with a range of Uu RSRP (e.g., min_Uu_RSRP and max_Uu_RSRP). The range of the Uu RSRP can be used to send multipath discovery-relay-service messages. For example, a WTRU may send a multipath discovery-relay-service message if the measured Uu RSRP is within the configured range of the Uu RSRP. In some scenarios, if the measured Uu RSRP is outside the configured range, the WTRU may not send a multipath discovery-relay-service message.

[0126] The parameters and / or conditions for sending discover-relay-service messages may include resource pools and / or resource pool types for sending certain types of discover-relay-service messages. For example, a WTRU may be (pre-configured) with a dedicated resource pool for sending multipath discover-relay-service messages. For example, a WTRU may be (pre-configured) with a set of shared resource pools for sending multipath discover-relay-service messages.

[0127] The parameters and / or conditions for discover-relay-service transmission may include parameters for discover-relay-service transmission. For example, the parameters may include one or more of the following for each discover-relay-service message (e.g., a multipath discover-relay-service message): range transmit power, MCS, number of subchannels, number of retransmissions, and / or transmit periodicity.

[0128] Parameters and / or conditions for discovery-relay-service transmission may include the minimum Uu RSRP of the relay and / or the minimum SL-RSRP / SD-RSRP for the SLRB / LCH. For example, a WTRU (e.g., a remote WTRU or relay WTRU) may be (pre) configured with the minimum Uu RSRP and / or the minimum SL-RSRP / SD-RSRP of the relay WTRU to establish a multipath relay service for one or more SLRB / LCHs for a multipath relay service. For example, for an SLRB / LCH associated with a multipath relay service, the WTRU may establish a multipath connection with the relay if the relay's Uu RSRP is greater than or equal to a threshold and / or the SL-RSRP / SD-RSRP is greater than another threshold.

[0129] A WTRU can indicate to the network its supported relay service capabilities. For example, a WTRU may indicate to the network whether it supports one or more of the following relay services: single-path, multi-path, single-hop, multi-hop, Layer 2, and / or Layer 3 relay services.

[0130] A WTRU may receive instructions from the network indicating what type of relay it should operate as. The WTRU may then (for example,) send / receive discovery-relay-service messages associated with the relay type indicated by the network.

[0131] A WTRU may request resources for discovery resources. A WTRU may trigger a discovery-relay-service transmission for a certain type of discovery-relay-service message. A WTRU may request sidelink resources from the network for transmissions (e.g., such as). A WTRU may indicate what type of discovery-relay-service message (e.g., the type the WTRU wishes to transmit) to transmit. For example, a WTRU may be (pre)configured for each type of discovery-relay-service message with an LCG and / or destination ID / destination index. A WTRU may request the availability of discovery-relay-service data (e.g., via an SL BSR) using the LCG and / or destination ID / index. A WTRU may (e.g., then) expect to receive sidelink resources to transmit a type of discovery-relay-service message.

[0132] A WTRU (e.g., a relay WTRU) may report a set of remote WTRUs (e.g., discovered remote WTRUs). A set of remote WTRUs may include one or more remote WTRUs (e.g., one or more discovered remote WTRUs). A WTRU (e.g., a relay WTRU) may monitor discovery messages (e.g., solicitation messages) from one or more remote WTRUs. A WTRU may report a set of discovered remote WTRUs, for example, after monitoring discovery messages. A WTRU may be (pre)configured with an SD-RSRP threshold. An SD-RSRP threshold may be associated with a set of remote WTRUs (e.g., reporting a set of remote WTRUs). For example, a WTRU may report a set of discovered remote WTRUs if the SD-RSRP sent from a remote WTRU is greater than a (pre)configured threshold. A WTRU may be indicated in (e.g., each) solicitation message (e.g., a solicitation message associated with one or more types requesting relay services). For example, a WTRU may indicate whether a remote WTRU is requesting single-path relay services, multi-path relay services, single-hop relay services, and / or multi-hop relay services. A WTRU may transmit (e.g., indicate) to the network what type of relay service each reported remote WTRU is requesting. In some examples, a WTRU may report to the network a set of remote WTRUs requesting one type of relay service. For example, a WTRU may report a set of remote WTRUs requesting multipath relay service. For example, a WTRU may report a set of remote WTRUs requesting singlepath relay service.

[0133] A relay WTRU may determine which set of detected remote WTRUs to report to the network. A WTRU (e.g., a relay UE) may determine which set of detected remote WTRUs to report to the network based on one or more of the following: A WTRU may determine which set of detected remote WTRUs to report to the network based on the (pre)configured relay type. For example, a WTRU may report a set of detected remote WTRUs based on its (pre)configured relay type. For example, if a WTRU is (pre)configured with a multipath relay type, it may report a set of remote WTRUs requesting multipath services. For example, if a WTRU is (pre)configured with a singlepath relay service, it may report a set of remote WTRUs requesting only singlepath relay services.

[0134] A WTRU may determine which set of detected remote WTRUs should report to the network based on the relay's Uu RSRP. For example, a WTRU may report a set of remote WTRUs requesting multipath relay if the Uu RSRP meets the (pre)configured Uu RSRP threshold for multipath relay (e.g., Uu RSRP is greater than the Uu RSRP threshold). Alternatively or additionally, a WTRU may report a set of remote WTRUs requesting single-path relay service if the Uu RSRP meets the (pre)configured Uu RSRP threshold for single-path relay (e.g., Uu RSRP is greater than one Uu RSRP threshold but less than another). In another example, a WTRU may report all detected remote WTRUs requesting relay service (e.g., both single-path and multipath) if the Uu RSRP meets the (pre)configured Uu RSRP thresholds for both single-path and multipath relay services.

[0135] A WTRU may report a set of relay WTRUs (e.g., detected relay WTRUs). A set of relay WTRUs may include one or more relay WTRUs (e.g., one or more detected relay WTRUs). A WTRU (e.g., a remote WTRU) may monitor one or more discovery messages from one or more relay WTRUs. A WTRU may report a set of detected relay WTRUs (e.g., then). A WTRU may be (pre)configured with an SD-RSRP threshold. An SD-RSRP threshold may be associated with a set of relay WTRUs (e.g., reporting a set of relay WTRUs). A WTRU may report detected relay WTRUs. For example, a WTRU may report detected relay WTRUs if the SD-RSRP sent from a relay WTRU is greater than a (pre)configured threshold. In each discovery message, a WTRU may transmit (e.g., indicate) the type of relay service (e.g., the relay service being provided). For example, a WTRU may transmit (e.g., indicate) whether a relay WTRU provides single-path relay service, multipath relay service, single-hop relay service, and / or multi-hop relay service. The WTRU may then indicate to the network (e.g., for reported relay WTRUs) what type of relay service the relay WTRU provides. In some examples, a WTRU may report to the network a set of relay WTRUs providing one or more (e.g., one) types of relay service. For example, a WTRU may report a set of relay WTRUs providing multipath relay service. For example, a WTRU may report a set of relay WTRUs providing single-path relay service.

[0136] A WTRU may determine which set of relay WTRUs (e.g., discovered relay WTRUs) should report to the network. A set of relay WTRUs may include one or more relay WTRUs (e.g., one or more discovered relay WTRUs). A WTRU (e.g., a remote WTRU) may monitor one or more discover-relay-service messages from one or more WTRUs. A WTRU may determine which set of discovered relay WTRUs should report to the network based on one or more of the conditions herein (e.g., the following conditions). A WTRU may determine which set of discovered relay WTRUs should report to the network based on the (pre)configured type of relay. For example, a WTRU may be (pre)configured to report one type of discovered relay (e.g., a relay supporting multipath services). A WTRU may (pre) report a set of relays (e.g., relays supporting multipath services) that support the (pre)configured type.

[0137] A WTRU may determine which set of detected relay WTRUs should report to the network based on the Uu RSRP of a remote WTRU. For example, if its Uu RSRP is greater than a threshold, the WTRU may report a set of relay WTRUs that support multipath services. In another example, if its Uu RSRP is less than a threshold, the WTRU may report all detected relays and / or relays that support single-path relay services.

[0138] A WTRU may determine which set of detected relay WTRUs should report to the network based on its connectivity status (for example, whether the WTRU is connected via a Uu or directly to the gNB via a U2N relay). For example, when connected to the gNB via a Uu, the WTRU may report the set of detected relays that support multipath relaying. In another example, when connected to the gNB via a different relay, the WTRU may report all detected relays, or the set of detected relays that support single-path relaying services.

[0139] A WTRU may determine which set of discovered relay WTRUs should be reported to the network based on the relay WTRU's Uu RSRP. The Uu RSRP may be indicated in the relay WTRU's discover-relay-service message. For example, a WTRU may be (pre)configured to monitor one or more discover-relay-service messages from relays in order to request multipath service. In some examples, a WTRU may report a set of relays with a Uu RSRP greater than a (pre)configured threshold. For example, a WTRU may be (pre)configured to monitor one or more discover-relay-service messages from one or more relay WTRUs. A WTRU may be (pre)configured to monitor one or more discover-relay-service messages from one or more relay WTRUs in order to request single-path relay service. A WTRU may report a set of relay WTRUs with a Uu RSRP greater than and / or below a threshold (e.g., a different threshold).

[0140] A WTRU may determine which set of detected relay WTRUs should report to the network, for example, based on the QoS of an established SLRB / LCH. For example, a WTRU may report relay WTRUs with a Uu RSRP higher than a threshold. The threshold may be a function of the QoS of the established SLRB / LCH. For example, for a first established SLRB / LCH, a WTRU may report relay WTRUs with a Uu RSRP greater than the first threshold. Additionally or alternatively, for a second established SLRB / LCH, a WTRU may report relay WTRUs with a Uu RSRP greater than the second threshold.

[0141] A relay WTRU may indicate information in discovery messages. For example, a relay WTRU may indicate Uu information in the network. A relay WTRU may indicate Uu information in the network to support remote WTRUs in relay selection. A WTRU may indicate one or more of the Uu information described herein (e.g., below). A WTRU may indicate the distance to the gNB. Additionally or alternatively, a WTRU may indicate the location of the WTRU. For example, a WTRU may indicate whether the WTRU is at a cell edge or at the center of the cell. In some examples, a WTRU may be assumed to support single-path and / or multi-path relay services (e.g., any of the relay services) when the relay is at a cell edge. Alternatively or additionally, when the relay WTRU is at the center of the cell, it may support multi-path relay services (e.g., only).

[0142] A remote WTRU may indicate its connection status in a discovery service message. For example, when a WTRU sends a discovery request message, it may indicate one or more of the following parameters in the discovery-service message: The remote WTRU may indicate the Uu connection status (e.g., whether the remote WTRU is connected to the gNB, and / or whether it is connected to the gNB via the Uu and / or another U2N relay). Alternatively or additionally, the remote WTRU may indicate the Uu RSRP. Alternatively or additionally, the remote WTRU may indicate the distance to the gNB.

[0143] A WTRU may request one or more resources for discovery-relay-service transmissions. For example, a WTRU may request a sidelink resource for discovery transmissions (e.g., a solicitation message or an announcement message). A WTRU may also indicate to the network, as an alternative or additional measure, the relay services it provides / requests. This approach can help the network appropriately schedule resources for the WTRU.

[0144] A WTRU may receive instructions to send a discovery-relay-service message. For example, the network may send a message to the WTRU indicating what type of relay service it needs to request / provide. For example, the network may indicate to the WTRU whether it should request / provide single-path, multipath, single-hop, and / or multi-hop relay services. The WTRU may then send a discovery message indicating to the network that the WTRU is providing / requesting. Alternatively or additionally, the WTRU may send a message to the network indicating what type of relay service it needs to request / provide. For example, the WTRU may indicate to the network whether it should request / provide single-path, multipath, single-hop, and / or multi-hop relay services.

[0145] A WTRU may report a set of discovered remote WTRUs. For example, a WTRU (e.g., a relay WTRU) may monitor discovery messages (e.g., solicitation messages) from remote WTRUs. The WTRU may then report a set of discovered remote WTRUs. A WTRU may be (pre)configured with an SD-RSRP threshold. Additionally or alternatively, a WTRU may report discovered remote WTRUs. For example, a WTRU may report discovered remote WTRUs if the SD-RSRP sent from a remote WTRU is greater than a (pre)configured threshold. In each solicitation message, the WTRU may indicate the type of relay service being requested. For example, the WTRU may indicate whether a remote WTRU is requesting one or more of the following: single-path relay service, multi-path relay service, single-hop relay service, and / or multi-hop relay service. For each reported remote WTRU, the WTRU may indicate to the network what type of relay service the remote WTRU is requesting. A WTRU may report to the network a set of remote WTRUs requesting one type of relay service. For example, a WTRU may report a set of remote WTRUs requesting multipath relay service. For example, a WTRU may report a set of remote WTRUs requesting singlepath relay service.

[0146] A relay WTRU may determine which set of remote WTRUs (e.g., detected remote WTRUs) should report to the network. A set of remote WTRUs may include one or more remote WTRUs (e.g., one or more detected remote WTRUs). A WTRU (e.g., a relay WTRU) may determine which set of detected remote WTRUs should report to the network based on one or more of the conditions specified herein (e.g., the following conditions). A WTRU (e.g., a relay WTRU) may determine which set of detected remote WTRUs should report to the network based on the (pre)configured relay type. For example, a WTRU may report a set of detected remote WTRUs based on its (pre)configured relay type. For example, a WTRU may report a set of remote WTRUs requesting multipath services if it is (pre)configured with a multipath relay type. For example, a WTRU may report a set of remote WTRUs requesting only singlepath relay services if it is (pre)configured with a singlepath relay service.

[0147] A WTRU (e.g., a relay WTRU) may determine which set of detected remote WTRUs should report to the network based on the relay's Uu RSRP. For example, a WTRU may report a set of remote WTRUs requesting multipath relay if the Uu RSRP meets the (pre)configured Uu RSRP threshold for multipath relay (e.g., Uu RSRP is greater than the Uu RSRP threshold). Alternatively or additionally, a WTRU may report a set of remote WTRUs requesting single-path relay service if the Uu RSRP meets the (pre)configured Uu RSRP threshold for single-path relay (e.g., Uu RSRP is greater than one Uu RSRP threshold and less than another). In another example, a WTRU may report all detected remote WTRUs requesting relay service (e.g., both single-path and multipath) if the Uu RSRP meets the (pre)configured Uu RSRP thresholds for both single-path and multipath relay services.

[0148] A WTRU may report a set of discovered relays. For example, a WTRU (e.g., a remote WTRU) may monitor discovery messages. A WTRU may monitor discovery messages from one or more relay WTRUs. A WTRU may report a set of discovered relay WTRUs (e.g., then). A WTRU may be (pre)configured with an SD-RSRP threshold. A WTRU may report discovered relay WTRUs using an SD-RSRP threshold. For example, a WTRU may report discovered relay WTRUs if the SD-RSRP sent from a relay WTRU is greater than a (pre)configured threshold. A WTRU may be indicated in one or more (e.g., each) discovery messages. For example, the type of relay service it provides may be indicated in one or more (e.g., each) discovery messages. In some examples, a WTRU may indicate whether a relay WTRU provides single-path relay service, multi-path relay service, single-hop relay service, and / or multi-hop relay service. Next, a WTRU may indicate (e.g., send / report) to the network (e.g., for each reported relay WTRU) which type of relay service it provides. A WTRU may report (e.g., send a report message) to the network a set of relay WTRUs providing one or more (e.g., one) types of relay service. For example, a WTRU may report a set of relay WTRUs providing multipath relay service. For example, a WTRU may report a set of relay WTRUs providing singlepath relay service.

[0149] A WTRU may determine which set of relay WTRUs (e.g., discovered relay WTRUs) should report to the network. A set of relay WTRUs may include one or more relay WTRUs (e.g., one or more discovered relay WTRUs). A WTRU (e.g., a remote WTRU) may monitor discover-relay-service messages from one or more relays (e.g., multiple relays). A WTRU may determine which set of discovered relay WTRUs should report to the network based on one or more of the following: A WTRU may determine which set of discovered relay WTRUs should report to the network based on the (pre)configured type of relay. For example, a WTRU may be (pre)configured to report discovered relays of one or more types (e.g., one relay) (e.g., relays supporting multipath services). A WTRU may (e.g.,) report a set of relays that support the (pre)configured type (e.g., relays supporting multipath services).

[0150] A WTRU may determine which set of detected relay WTRUs should report to the network based on the Uu RSRP of a remote WTRU. For example, a WTRU may report a set of relay WTRUs that support multipath services if its Uu RSRP (e.g., of a relay WTRU) is greater than a threshold. In another example, if its Uu RSRP is less than a threshold, a WTRU may report all detected relays or relays that support single-path relay services.

[0151] A WTRU may determine which set of detected relay WTRUs should report to the network based on its connectivity status (for example, whether the WTRU is connected via a Uu or directly to the gNB via a U2N relay). For example, when connected to the gNB via a Uu, the WTRU may report the set of detected relays that support multipath relaying. In another example, when connected to the gNB via a different relay, the WTRU may report all detected relays, or the set of detected relays that support single-path relaying services.

[0152] A WTRU may determine which set of discovered relay WTRUs should be reported to the network based on the relay WTRU's Uu RSRP. The relay WTRU's Uu RSRP may be indicated in the relay WTRU's discover-relay-service message. For example, a WTRU may be (pre)configured to monitor discover-relay-service messages from relays in order to request multipath services. A WTRU may report a set of relays with a Uu RSRP greater than a (pre)configured threshold. For example, a WTRU may be (pre)configured to monitor discover-relay-service messages from relays in order to request singlepath relay services. A WTRU may report a set of relay WTRUs with a Uu RSRP greater than (e.g., a first) threshold and / or less than another (e.g., a second) threshold.

[0153] A WTRU can determine which set of detected relay WTRUs should be reported to the network based on the QoS of the established SLRB / LCH. For example, a WTRU may report relay WTRUs with Uu RSRP exceeding a threshold. The threshold may be a function of the QoS of the established SLRB / LCH. For example, for a first established SLRB / LCH, a WTRU may report relays with Uu RSRP exceeding a first threshold. Additionally or alternatively, for a second established SLRB / LCH, a WTRU may report relays with Uu RSRP greater than a second threshold (e.g., a different threshold).

[0154] A WTRU may request one or more resources for discovery-relay-service transmissions. For example, a WTRU may request one or more sidelink resources for discovery transmissions (e.g., request messages and / or notification messages). A WTRU may also indicate to the network (e.g., transmit) the relay services it provides / requests. This WTRU may help the network schedule one or more resources to the WTRU.

[0155] A WTRU may receive instructions to send a discovery-relay-service message. For example, a WTRU may receive instructions from the network. The instructions may indicate what type of relay service the WTRU should request and / or provide. For example, the instructions may indicate whether the WTRU should request / provide single-path, multipath, single-hop, and / or multi-hop relay services. A WTRU may send one or more discovery messages. One or more discovery messages may include the type of relay service the WTRU is providing and / or requesting (e.g., indicated by the network).

[0156] A WTRU may send one or more autonomous discovery messages. For example, a WTRU may decide to perform a discovery-relay-service message transmission (e.g., send a discovery-relay-service message). A WTRU may trigger a discovery-relay-service transmission and / or relay (re)selection. For example, a WTRU may trigger a discovery-relay-service transmission and / or relay (re)selection based on one or any combination of the following events / conditions: Uu RSRP has a (pre)configured range, relay load, instructions from another node (e.g., gNB), reception of an SLRB / LCH configuration (e.g., an SLRB / LCH configuration including at least one SLRB / LCH that requires multipath relay service), arrival of data from a set of SLRB / LCHs into the buffer, the amount of data from a set of SLRB / LCHs is greater than or equal to a threshold, reception of a discovery-relay message from another WTRU, the CBR of the resource pool associated with the discovery-relay message transmission is less than a threshold, and / or the distance to the gNB is within a configured range.

[0157] A WTRU may trigger discover-relay-service transmissions and / or relay (re)selection based on whether the Uu RSRP is within a (pre)configured range. For example, a WTRU can be (pre)configured with a range of Uu-RSRP (e.g., min_Uu_RSRP, and / or max_Uu_RSRP) to send discover-relay-service messages. In some examples, a WTRU may trigger a discover-relay-service transmission if the measured Uu-RSRP is within a (pre)configured range. In other examples, if the measured Uu-RSRP is outside a (pre)configured range, the WTRU may not send a message.

[0158] A WTRU may trigger discover-relay-service transmissions and / or relay (re)selections based on relay load. For example, a WTRU (e.g., a relay WTRU) may be (pre) configured with a relay load range (e.g., to send discover-relay-service messages). The WTRU may then (e.g.,) send discover-relay-service messages if the load on the WTRU is within the (pre) configured range.

[0159] A WTRU may trigger a discover-relay-service transmission and / or relay (re)selection based on instructions from another node (e.g., a gNB). For example, another node (e.g., a gNB) may instruct and / or request a WTRU to perform a discover-relay-service transmission. The WTRU may then (for example,) transmit a discover-relay-service message (for example, based on a request and / or instruction from the node).

[0160] A WTRU may trigger a discover-relay-service transmission and / or relay (re)selection based, for example, on an SLRB / LCH configuration (e.g., its reception). An SLRB / LCH configuration may include one or more SLRB / LCHs that require multipath relay services. For example, a WTRU may receive an SLRB / LCH configuration from another node (e.g., a gNB) that may include one or more SLRB / LCHs that require multipath relay services (e.g., SLRB / LCHs with priority and / or reliability above a threshold). The WTRU may then trigger a discover-relay-service transmission. The WTRU may send a discover-relay-service message, which may request multipath relay services, for example.

[0161] A WTRU may trigger a discover-relay-service message and / or relay (re)selection based on the arrival of data from a set of SLRBs / LCHs into its buffer. For example, a WTRU (e.g., a remote WTRU) may be (pre)configured with one or more SLRBs / LCHs for multipath relay service. The WTRU may then trigger the transmission of a discover-relay-service message. The discover-relay-service message may request multipath relay service.

[0162] A WTRU may trigger a discover-relay-service transmission and / or relay (re)selection based on whether the amount of data from a set of SLRBs / LCHs is above a threshold. For example, a WTRU (e.g., a remote WTRU) may (pre)configure one or more SLRBs / LCHs for multipath relay services. The WTRU may (pre)configure a minimum amount of data from a set of SLRBs / LCHs for multipath relays to trigger a discover-relay-service transmission. The WTRU may then trigger a discover-relay-service message transmission requesting multipath relay services if the amount of data in the set of SLRBs / LCHs is above a threshold. The threshold may (pre)configure.

[0163] A WTRU may trigger a discover-relay-service transmission and / or relay (re)selection based on whether the amount of data from the set of SLRBs / LCHs is greater than a threshold (e.g., exceeds a threshold). For example, a WTRU (e.g., a remote WTRU) may be (pre) configured with one or more SLRBs / LCHs for multipath relay services. A WTRU may be (pre) configured with a minimum amount of data from the set of SLRBs / LCHs for multipath relays to trigger a discover-relay-service transmission. A WTRU may then (e.g.,) trigger a discover-relay-service message transmission. A discover-relay-service message may contain a multipath relay service request. For example, a discover-relay-service message may contain a multipath relay service request if the amount of data in the set of SLRBs / LCHs is greater than or equal to a threshold. The threshold may be (pre) configured.

[0164] A WTRU may trigger a discover-relay-service send and / or relay (re)selection based on the reception of a discover relay message from another WTRU. For example, a WTRU may determine whether to send a discover message based on the reception of a discover message providing (e.g., the same) relay service. For example, a WTRU may monitor one or more discover messages from one or more other relay WTRUs. A WTRU may determine whether to send a discover message based on whether it should receive a discover message (e.g., any) that has an SD-RSRP greater than, for example, a threshold. In some examples, if a WTRU detects a discover message that provides the same relay service and has an SD-RSRP greater than a (pre-configured) threshold, the WTRU may not send a discover message. In other examples, a WTRU may send a discover message (e.g., otherwise).

[0165] A WTRU may trigger discovery-relay-service transmission and / or relay (re)selection based on whether the resource pool's CBR is below a threshold. For example, the resource pool's CBR may be associated with discovery relay messages. A WTRU may be (pre)configured, for example, with dedicated resource pools for transmitting one or more types of discovery messages for one or more types of relay services. A WTRU may decide to transmit a discovery message, for example, if the resource pool's CBR is below a threshold. In other examples (e.g., cases other than those described above), a WTRU may not transmit a discovery message.

[0166] A WTRU may trigger discover-relay-service transmissions and / or relay (re)selection based on its distance to the gNB. For example, a WTRU may trigger discover-relay-service transmissions and / or relay (re)selection based on whether the distance to the gNB is within a configured range. For example, a WTRU (e.g., a relay WTRU) may determine whether to send a particular discover-relay message based on its distance to the gNB. In some examples, a WTRU may be (pre)configured with a range of distances to the gNB to send, for example, a multipath discover-relay-service message. In some examples, a WTRU may trigger a discover transmission if the distance between the WTRU and the gNB is within a (pre)configured range.

[0167] A WTRU may decide to send one or more discover-relay-service messages (e.g., discover-relay-service messages). For example, a WTRU (e.g., a relay WTRU) may be (pre-configured) with a Uu RSRP range (e.g., [Uu RSRP threshold 1, Uu RSRP threshold 2]). The Uu RSRP range may be associated with sending discover-relay-service messages. In one example, if a WTRU supports single-path relay services, it may send a discover-relay-service message if the WTRU's Uu RSRP is within the range. In another example, if a WTRU supports multi-path relay services, it may ignore the upper limit of the (pre-configured) Uu RSRP threshold range and send a discover-relay-service message. For example, a WTRU may send a discover-relay-service message if the Uu RSRP is greater than the Uu RSRP threshold (e.g., Uu RSRP > Uu RSRP threshold 1).

[0168] A WTRU may determine whether a cell supports one or more relay services (e.g., one relay service). For example, a WTRU may determine whether a cell supports a particular relay service (e.g., a multipath relay service). A WTRU may receive an SIB. An SIB may implicitly or explicitly indicate whether a relay service is supported (e.g., an SIB may implicitly or explicitly indicate whether a multipath relay service is supported).

[0169] A WTRU may determine whether to send one or more discover-relay-service messages (e.g., discover-relay-service messages) based on one or more instructions from a cell. For example, a WTRU may be (pre)configured with a Uu RSRP range (e.g., [Uu RSRP threshold 1, Uu RSRP threshold 2]). The Uu RSRP range may be associated with sending discover-relay-service messages. A WTRU may have a Uu RSRP that exceeds a second Uu RSRP threshold (e.g., Uu RSRP threshold 2). A WTRU may then determine whether to send a discover message based on whether the cell supports multipath relay services. For example, if the cell supports multipath relay services, the WTRU may send a discover-relay-service message. In another example, if the cell does not support multipath relay services, the WTRU may not send a discover-relay-service message.

[0170] A WTRU may determine whether it should respond to a remote WTRU. A WTRU (e.g., a relay WTRU) may, for example, perform one or more of the actions described herein (e.g., the following actions) to respond to a remote WTRU upon detection / reception of a discover-relay-service message. A WTRU (e.g., a relay WTRU) may perform resource allocation and / or send a response message to the remote WTRU. In another example, a WTRU (e.g., a relay WTRU) may request sidelink resources to respond to a remote WTRU. As an addition or alternative, a WTRU (e.g., a relay WTRU) may report the discovered remote WTRU to the network.

[0171] A relay WTRU supporting a multipath relay service may determine whether to respond to a remote WTRU based on one or more conditions as defined herein (for example, the following conditions). A WTRU may determine whether to respond to a remote WTRU based on its Uu RSRP. For example, a WTRU may be (pre)configured with a Uu RSRP threshold to be a multipath relay. For example, a WTRU may respond to a remote WTRU if the Uu RSRP exceeds the threshold. In another example, a WTRU may not respond to a remote WTRU if the Uu RSRP does not exceed the threshold.

[0172] A relay WTRU may determine whether to respond to a remote WTRU based on one or more types of relay services requested. For example, a WTRU may not respond to a remote WTRU requesting single-path relay services. A WTRU may respond to a remote WTRU requesting multi-path relay services. Additionally or alternatively, a relay WTRU may determine whether to respond to a remote WTRU based on whether the cell supports multi-path relay services. For example, a WTRU may not respond to a remote WTRU requesting multi-path services. For example, a WTRU may respond to a remote WTRU requesting single-path relay services if the relay WTRU supports both multi-path and single-path relay services.

[0173] A WTRU may determine which discover-relay-service message to send. For example, a WTRU (e.g., a relay WTRU) may decide to send a discover-relay-service message. A WTRU may determine which type of discover-relay-service message to send based on one or more of the following: measured Uu RSRP, relay load, relay capacity, requested relay service, intended relay service to support, instructions from another node (e.g., gNB), priority associated with each discover-relay-service message, predefined transmission order of each discover-service message, and / or distance to the gNB.

[0174] A WTRU may determine which type of discover-relay-service message to send based on the measured Uu RSRP. In some examples, a WTRU (e.g., a relay WTRU) may be (pre)configured with a range of Uu RSRP (e.g., min_Uu_RSRP, and / or max_Uu_RSRP) to send (e.g., each) type of discover-relay-service message. For example, a WTRU may be pre-configured with one or more (e.g., two) ranges of Uu RSRP thresholds and / or receive (e.g., via RRC and / or SIB). A first range (e.g., a first range of Uu RSRP thresholds) may be associated with single-path relay services, and / or a second range (e.g., a second range of Uu RSRP thresholds) may be associated with multi-path relay services. The WTRU may then determine (e.g., which) discover-relay-service message to send based on whether the Uu RSRP is within (e.g., which) pre-configured range. For example, a WTRU may be (pre-configured) with two Uu RSRP ranges, one of which may be associated with single-path relay services and the other with multipath relay services. A WTRU may decide (for example, then) to send a single-path discover-relay-service message if, for example, the Uu RSRP is within the range (pre-configured) for single-path relay. A WTRU may decide to send a multipath discover-relay-service message if, for example, the measured Uu RSRP is within the range (pre-configured) for multipath relay services. In some examples, if a WTRU satisfies two Uu RSRP ranges (e.g., a first range and a second range), it may send a preferred discover-relay-service message. A WTRU may be (pre-configured) with which type of discover service message is preferred. For example, a WTRU may be (pre-configured) to prefer single-path discover service messages. Alternatively or additionally, the WTRU may be (pre-configured) to prioritize multipath discovery service messages.In some cases, a WTRU may send a discovery-service message that implicitly and / or explicitly indicates that the WTRU supports both single-path relay services and multi-path relay services.

[0175] For example, a WTRU (e.g., a remote WTRU) may be (pre) configured with one or more (e.g., two) ranges of the Uu RSRP threshold, where the first range may be associated with requests for single-path relay services and / or the second range may be associated with requests for multi-path relay services. The WTRU may then (e.g.,) determine which request message to send based on whether the Uu RSRP is within the first and / or second range of the Uu RSRP. In some examples, the WTRU may send a request for single-path relay services if the Uu RSRP is within the first range, and / or send a request message for multi-path relay services if the Uu RSRP is within the second range. If the Uu RSRP satisfies both ranges, the WTRU may, in some examples, send a preferred request message. Alternatively or additionally, if the Uu RSRP satisfies both ranges, the WTRU may send a request message for, for example, single-path and / or multi-path relay services (e.g., either one).

[0176] A WTRU may determine, based on the relay load, what type of discover-relay-service message it should send. A WTRU (e.g., a relay WTRU) may be (pre-configured) with one or more (e.g., two) relay load ranges to send discover-relay-service messages. One (e.g., one) relay load range may be used for single-path relaying, and / or another (e.g., another) relay load range may be used for multi-path relaying services. If the relay load is within the first relay load range, the WTRU may send a single-path discover-relay-service message. In other examples (e.g., not mentioned above), if the relay load is within the second relay load range, the WTRU may send a multi-path discover-relay-service message.

[0177] A WTRU may determine which type of discover-relay-service message to send based on its relay capabilities (e.g., a relay WTRU). For example, a WTRU (e.g., a relay WTRU) may determine which discover-relay-service message to send based on its relay capabilities. In some examples, a WTRU may satisfy the conditions for sending multiple types of discover-relay-service messages. A WTRU may determine which message to send based on its capabilities (e.g., then). For example, a WTRU may satisfy the conditions for sending a single-path discover-relay-service message and / or a multi-path discover-relay-service message (e.g., either). A WTRU may send a single-path discover-relay-service message if, for example, it supports single-path relay services (e.g., only). In other examples (e.g., otherwise), a WTRU may send a multi-path discover-relay-service message if it supports multi-path relay services (e.g., only).

[0178] A WTRU may determine which type of discovery-relay-service message to send based on the requested relay service. In some cases, a WTRU may send a multipath discovery-relay-service message if it is requested to perform multipath discovery-relay-service message transmission (for example, from another node or from the WTRU's application layer).

[0179] A WTRU may determine which type of discover-relay-service message to send based on the relay services it intends to support. For example, a WTRU may determine which relay services it should support. A WTRU may then determine which discover-relay-service message to send based on the relay services it has decided to support (for example, desired). In some cases, a WTRU may decide to support single-path relay (for example, become a single-path relay) and / or a WTRU may send a single-path discover-relay-service message. In other cases, a WTRU may decide to support multi-path relay (for example, become a multi-path relay) and / or a WTRU may send a multi-path discover-relay-service message.

[0180] A WTRU may determine what type of discovery-relay-service message to send based on instructions and / or requests from another node (e.g., a gNB). In some examples, a WTRU may (for example, first) indicate to the network the relay capabilities it supports. The WTRU may (for example, then) receive instructions from the network. These instructions may indicate which (one or more) relay services it should support. Based on the instructions from the network regarding which relay services it should support, the WTRU may determine what discovery-relay-service message to send.

[0181] A WTRU may determine which type of discover-relay-service message to send based on the priority associated with each discover-relay-service message. For example, a WTRU may be pre-configured with the priority associated with each discover-relay-service message. In some examples, a WTRU may decide to send a discover message with a higher priority if the conditions for sending multiple discover-relay-service messages are met. For example, a WTRU may be pre-configured so that single-path relay service messages have a higher priority than multi-path relay service messages. A WTRU may then decide to send a single-path discover-relay-service message if the conditions for sending both single-path and multi-path discover-relay-service messages are met. For example, a WTRU may be pre-configured so that multi-path relay service messages have a higher priority than single-path relay service messages. A WTRU may then decide to send a multi-path discover-relay-service message if the conditions for sending multi-path discover-relay-service messages are met.

[0182] A WTRU may determine which type of discover-relay-service message to send based on a predefined transmission order of each discover-relay-service message. A WTRU may be (pre)configured with the transmission order of (each) discover-relay-service messages, for example, when other conditions for sending multiple discover-relay-service messages are met. In some examples, a WTRU may send a single-path discover-relay-service message if the conditions for sending a single-path discover-relay-service message and / or a multi-path discover-relay-service message (e.g., both) are met. For example, a WTRU may send a multi-hop discover-relay-service message if the conditions for sending a single-hop and / or multi-hop discover-relay-service message (e.g., both) are met.

[0183] A WTRU may determine which type of discovery-relay-service message to send based on the distance to the gNB. For example, a WTRU may be (pre)configured using one or more (e.g., multiple) ranges of distance to the gNB. Each range may be associated with one type of relay service message (e.g., one range may be associated with a single-path relay service message, another with a multi-path relay service message). The WTRU may then determine (e.g., which) relay service message to send based on the distance to the gNB.

[0184] Figure 4 illustrates an exemplary system 400 illustrating WTRUs that determine whether to send a single-path discovery versus (e.g., and / or) multipath discovery and a single-path request versus a multipath request. As shown in Figure 4, relay WTRU 406 may determine, based on Uu RSRP, whether to send a single-path discovery versus (e.g., and / or) multipath discovery service message. Additionally or alternatively, remote WTRU 402 may decide, based on Uu RSRP, to send a single-path request versus (e.g., and / or) multipath request message. For example, relay WTRU 406 may send a multipath discovery message if Uu RSRP is greater than Uu RSRP threshold 1 (e.g., a first threshold), and / or relay WTRU 404 may decide (e.g., send) a single-path discovery if Uu RSRP is between Uu RSRP threshold 1 (e.g., a first threshold) and Uu RSRP threshold 2 (e.g., a second threshold). The Uu RSRP threshold 2 (e.g., a second threshold) may be used to indicate coverage boundaries. Remote WTRU 408 may send one or more solicitation messages for multipath. For example, remote WTRU 408 may send one or more solicitation messages for multipath if its Uu RSRP is greater than Uu RSRP threshold 2 (e.g., a second threshold), and / or remote WTRU 402 may send one or more single-path solicitation messages if its Uu RSRP is less than Uu RSRP threshold 2 (e.g., a second threshold) and greater than Uu RSRP threshold 3 (e.g., a third threshold). Remote WTRU 402 and remote WTRU 408 may be the same WTRU and may, for example, move further away from or closer to gNB 410. Relay WTRU 406 and relay WTRU 404 may be the same WTRU and may, for example, move further away from or closer to gNB 410.

[0185] A WTRU may determine the QoS (e.g., priority) associated with a discover-relay-service message. The QoS (e.g., priority of a discover message) may be determined based on one or more of the (pre-)configuration of the discover-relay-service message, the resource pool, and / or the type of the resource pool (e.g., shared vs. dedicated). For example, a WTRU may be (pre-)configured with the priorities associated with each type of discover-relay-service message. A WTRU may determine the priority of a message based on (e.g., then) the type of discover-relay-service message that the WTRU sends. In some examples, a WTRU may be (pre-)configured with the priorities associated with one or more single-path discover-relay-service messages, and / or another priority associated with one or more multi-path discover-relay-service messages. A WTRU may determine the priority of a discover message based on (e.g., then) whether the discover-relay-service message is single-path or multi-path. In another example, a WTRU may be (pre-)configured with one or more (e.g., two) priorities for multipath discover-relay-service messages, based on whether the discover-relay-service message is sent in a shared resource pool and / or a dedicated resource pool. For example, if the message is sent in a dedicated resource pool, the WTRU may use one priority (e.g., first priority). If the message is sent in a shared resource pool, the WTRU may use another priority (e.g., second priority).

[0186] A WTRU may determine one or more resource pools for sending discover-relay-service messages. For example, a WTRU may be (pre-configured) with one or more dedicated resource pools for discover messages and / or with a shared resource pool that also handles other sidelink data transmissions for sending discover-relay-service messages.

[0187] The WTRU may determine which resource pool and / or which type of resource pool (e.g., a dedicated resource pool or a shared resource pool) sends discover-relay-service messages based on, for example, one or more of the following: the type of discover-relay-service message, the QoS of the discover-relay-service message, and / or the resource pool's CBR.

[0188] A WTRU may determine which resource pool and / or which type of resource pool (e.g., a dedicated resource pool or a shared resource pool) should send a discover-relay-service message based on the type of discover-relay-service message. For example, a WTRU may be (pre-configured) with one or more resource pools to send discover-relay-service messages. Additionally or alternatively, a WTRU may be (pre-configured) with one or more resource pools to send discover-relay-service messages of (e.g., each) type. A WTRU may determine which resource pool to send a discover-relay-service message to, based on (e.g.,) the type of discover message the WTRU is sending. For example, a WTRU may be (pre-configured) to use a dedicated resource pool for single-path discover-relay-service messages. A WTRU may be (pre-configured) to use a multipath discover-relay-service resource pool for WTRU multipath discover-relay-service messages. A WTRU may determine which type of resource pool to send to, based on (e.g.,) the type of discover-relay-service message the WTRU is sending. For example, WTRU may use a dedicated resource pool for single-path discovery messages and / or a shared resource pool for multi-path discovery messages.

[0189] A WTRU may determine which resource pool and / or which type of resource pool (e.g., a dedicated resource pool or a shared resource pool) should send a discover-relay-service message based on the QoS of the discover-relay-service message. For example, a WTRU may be (pre-configured) with one or more priorities (e.g., a set of priorities) to send discover messages in a resource pool of a certain type (e.g., one). A WTRU may determine which resource pool should send a discover message based, for example, on the priority associated with the discover message. In some examples, a WTRU may be (pre-configured) to use a dedicated resource pool with a priority of 1 (e.g., the highest priority) for discovering messages. A WTRU may be (pre-configured) to use a shared resource pool with a different priority (e.g., a priority value greater than 1 / a lower priority) for discovering messages. A WTRU may, for example, decide (e.g., send) a discovering message in a dedicated resource pool if the resource pool's priority is 1. In some examples (e.g., other than those mentioned above), a WTRU may send a discovering message in a shared resource pool.

[0190] A WTRU may determine, based on the resource pool's CBR, which resource pool and / or which type of resource pool (e.g., dedicated or shared resource pool) should send discover-relay-service messages. For example, a WTRU may be pre-configured to use a shared resource pool and / or a dedicated resource pool to send (e.g., one) type of discover message. Additionally or alternatively, a WTRU may be pre-configured to use a dedicated resource pool if the resource pool's CBR is below a threshold. In some cases (e.g., other than those mentioned above), a WTRU may use a shared resource pool. A WTRU may determine, based on the dedicated resource pool's CBR, whether to use a dedicated and / or shared resource pool. For example, a WTRU may use a dedicated resource pool if the resource pool's CBR is below a threshold. In another case (e.g., other than those mentioned above), a WTRU may use a shared resource pool if the dedicated resource pool's CBR is above a threshold. A CBR threshold may be pre-configured for each resource pool.

[0191] A WTRU may determine one or more transmission parameters of a discover-relay-service message. For example, a WTRU may determine one or more of the following discover-relay-service message transmission parameters: MCS, transmit power, the number of subchannels used for one or more (e.g., each) transmissions, the minimum, real, and / or maximum number of retransmissions for one or more (e.g., each) messages, and / or the frequency of discover-relay-service transmissions (e.g., discover transmission periodicity).

[0192] One or more of the discovery-relay-service message transmission parameters may be determined based on one or more of the following: the type of discovery-relay-service message, the resource pool for sending the discovery-relay-service message, the QoS associated with the discovery message, and / or the CBR of the resource pool.

[0193] One or more of the discover-relay-service message transmission parameters may be determined based on the type of discover-relay-service message. For example, a WTRU may be (pre-configured) with one or more ranges of one or more transmission parameters for one or more (e.g., each) types of discover-relay-service messages. The WTRU may then determine the transmission parameters of a discover-relay-service message based on, for example, the type of discover-relay-service message. In another example, a WTRU may be (pre-configured) with transmission power levels for one or more (e.g., each) types of discover-relay-service messages. The WTRU may then determine which transmission power level should be used based on the type of discover-relay-service message.

[0194] One or more of the discover-relay-service message transmission parameters may be determined based on the resource pool used to send the discover-relay-service message. For example, the WTRU may be (pre)configured with a range of one or more parameters for discover-relay-service transmissions per resource pool. The WTRU may then determine the transmission parameters of the discover-relay-service message based on, for example, the resources used to send the message.

[0195] One or more of the discover-relay-service message transmission parameters may be determined based on the QoS associated with the discover message. For example, a WTRU may be (pre-configured) with a QoS parameter (e.g., priority) (e.g., one) for each type of discover message. A WTRU may be (pre-configured) in a resource pool with a range of one or more transmission parameters for a discover message based on the message's QoS (e.g., priority). A WTRU may then (e.g.,) determine the transmission parameters of a discover-relay-service message based on the associated QoS (e.g., priority) of the discover-relay-service message.

[0196] A WTRU may determine which information should be included in one or more discovery messages. For example, a WTRU may decide to include one or more of the following in a discovery message: the type of discovery-relay-service message, the set of SLRB / LCHs to be supported and / or QoS, the maximum and / or minimum data rate, the measured Uu RSRP, the type of node (e.g., relay node vs. remote node), the minimum Uu RSRP and / or the minimum SL-RSRP / SD-RSRP, the WTRU's coverage status, and / or the WTRU's serving cell / gNB.

[0197] A WTRU may decide to include the type of discover-relay-service message in its discover message (e.g., send). For example, a WTRU (e.g., a relay WTRU) may indicate the type of discover-relay-service message in its message. A WTRU may implicitly and / or explicitly indicate in its discover-relay-service message what type of relay service it provides. For example, a WTRU may indicate whether it supports single-path relay service, multi-path relay service, single-hop relay service, and / or multi-hop relay service. In another example, a WTRU (e.g., a remote WTRU) may indicate the type of discover-relay-service in its message. A WTRU may implicitly and / or explicitly indicate what type of relay service it requests. For example, a WTRU may indicate whether it requests single-path relay service, multi-path relay service, single-hop relay service, and / or multi-hop relay service.

[0198] A WTRU may decide to include the set of SLRB / LCHs and / or QoS to be supported in the discovery message. For example, a remote WTRU may indicate the SLRB / LCHs and / or data QoS to be supported for a multipath service. The WTRU may indicate the QoS (e.g., priority, reliability, latency) of the data that triggers the discovery-relay-service transmission. In another example, a relay WTRU may indicate the SLRB / LCHs and / or data QoS to be supported for a multipath service. The WTRU may indicate the QoS (e.g., priority, reliability, latency) of the data that the relay WTRU can support.

[0199] A WTRU may decide to include (e.g., send) its maximum and / or minimum data rates in a discovery message. For example, a remote WTRU may indicate the maximum and / or minimum data rates required for the remote WTRU in a discovery message, for example, to support the relay WTRU when responding to its discovery-relay-service message. In another example, a relay WTRU may indicate the maximum and / or minimum data rates supported by the relay WTRU in a discovery message. Discovery messages may be used for remote WTRUs when performing relay (re)selection. A relay WTRU may indicate the current and / or instantaneous data rates for active relay connections when sending a discovery message, for example. Current and / or instantaneous data rate information may be used by the remote WTRU, along with (e.g., in conjunction with) the maximum and / or minimum data rates supported by the relay WTRU, when performing relay (re)selection.

[0200] A WTRU may decide to include (e.g., send) its measured Uu RSRP in the discovery message. For example, a WTRU (e.g., a relay WTRU) may indicate its measured Uu RSRP in a discovery-relay-service message. The measured Uu RSRP may be used to support remote WTRUs in relay (re)selection.

[0201] The WTRU may decide to include the node type (e.g., relay node vs. remote node) in the discovery message. For example, the WTRU may indicate whether it is a relay WTRU or a remote WTRU.

[0202] A WTRU may decide to include the minimum Uu RSRP and / or minimum SL-RSRP / SD-RSRP in its discover message. For example, a WTRU (e.g., a remote WTRU) may indicate the minimum Uu RSRP and / or minimum SL-RSRP / SD-RSRP in its discover-relay-service message, for example, to establish a multipath relay connection.

[0203] A WTRU may decide to include its coverage status in the discovery message. For example, a remote WTRU may indicate whether it is within and / or outside network coverage.

[0204] A WTRU may decide to include its serving cell and / or gNB in ​​its discovery message. For example, a remote and / or relay WTRU may indicate its cell and / or gNB in ​​its discovery message. This indication of the cell and / or gNB may help the WTRU prioritize relay WTRUs that support multipathing within the same cell and / or gNB.

[0205] Relay selection may be performed. For example, a WTRU may trigger relay (re)selection. In some examples, a WTRU may trigger relay (re)selection to select a relay (e.g., by itself). A WTRU may report the selected relay to the network (e.g., then). In another example, a WTRU (e.g., a remote WTRU) may trigger reporting to the network a set of relays discovered. In some examples, a WTRU (e.g., a relay WTRU) may trigger reporting a set of remote WTRUs discovered (e.g., a set of remote WTRUs sending discover-relay-service messages with SD-RSRP above a threshold). A WTRU may trigger one or more of the sets of relay selection, relay WTRU reports, and / or remote WTRU reports (e.g., remote WTRU reports to the network) based on one or more of the following: Uu RSRP is within a (pre)configured range, relay load, instructions from another node (e.g., a gNB), and / or arrival of data into the buffer from a set of SLRB / LCHs, or the amount of data from a set of SLRB / LCHs is above a threshold.

[0206] A WTRU may trigger one or more of the following actions based on, for example, whether the Uu RSRP is within a (pre)configured range: relay selection, reporting of a set of relay WTRUs, and / or reporting of a set of remote WTRUs (e.g., reporting to the network). For example, a remote WTRU may be triggered to report a set of detected relay WTRUs based on the Uu RSRP. In one example, if the Uu RSRP is within a (pre)configured range, the WTRU may report a set of detected relay WTRUs to the network (e.g., then). In another example, a remote WTRU may trigger relay selection if the Uu RSRP is within a threshold range.

[0207] A WTRU can trigger one or more actions based on relay load, for example, relay selection, reporting of a set of relay WTRUs, and / or reporting of a set of remote WTRUs (e.g., reporting to the network). For example, a relay WTRU might trigger reporting of a set of detected remote WTRUs to the network if the relay load is below a threshold. In another example, a relay WTRU might trigger reporting of a set of detected remote WTRUs to the network if the relay load is above a threshold.

[0208] A WTRU may trigger one or more of the following actions based on instructions from another node (e.g., a gNB): relay selection, reporting a set of relay WTRU reports, and / or reporting a set of remote WTRUs (e.g., reporting to the network). For example, a remote WTRU may be triggered to report a set of discovered relay WTRUs to the network based on a request from the network. The network may request the remote WTRU to report a set of discovered WTRUs (e.g., using a dedicated RRC message). The WTRU may then perform the reporting of the set of discovered relay WTRUs.

[0209] A WTRU may trigger one or more of the following actions based on, for example, the arrival of data from a set of SLRBs / LCHs into the buffer and / or the amount of data from the set of SLRBs / LCHs being above a threshold: relay selection, reporting of a set of relay WTRUs, and / or reporting of a set of remote WTRUs (e.g., reporting to the network). For example, a WTRU (e.g., a remote WTRU) may trigger relay selection and / or report to the network a set of detected relay WTRUs if the WTRU has data from a set of SLRBs / LCHs in its buffer and / or the amount of data from the set of SLRBs / LCHs is above a threshold. In another example, a WTRU (e.g., a remote WTRU) may trigger (re)selection if there is a change in the status of the buffered data (e.g., the amount of data associated with a set of existing SLRBs / LCHs increases). A change in the status of the buffered data may indicate, for example, an insufficient rate of depletion of the buffered data due to the currently selected relay. (Re)selection may be triggered by a second threshold. The initial arrival of data from the SLRB / LCH set can trigger and select a relay. Additionally, or alternatively, an increase in data exceeding a second threshold can trigger a (re)selection event. A (re)selection event can result in a change of the relay WTRU selected by the remote WTRU.

[0210] A WTRU can determine its load. A WTRU (e.g., a relay WTRU) can determine its load based on one or more of the conditions specified herein (e.g., the following conditions). For example, a WTRU (e.g., a relay WTRU) can determine its load based on its channel occupancy (CR). In another example, a WTRU (e.g., a relay WTRU) can determine its load based on the number of connected links. A WTRU (e.g., a relay WTRU) can determine its load based on its buffer status. In yet another example, a WTRU (e.g., a relay WTRU) can determine its load based on the number of connected remote WTRUs.

[0211] A WTRU may determine which relay to (re)select and / or which detected relay to report to the network based on one or more of the following: the relay WTRU's Uu RSRP, relay type, supported SLRB / LCH, relay WTRUs that support dual connectivity, relay WTRUs that support multipath within the same cell, and / or relay WTRUs in a cell / gNB that have a measured Uu RSRP above a threshold.

[0212] A WTRU may determine which relay to (re)select and / or which detected relay to report to the network based on the relay WTRU's Uu RSRP. For example, a WTRU may select a relay with a Uu RSRP and / or SD-RSRP above a threshold and / or report the detected relay to the network. The threshold may be a function of the WTRU's established SLRB / LCH.

[0213] A WTRU may determine, based on the relay type, which relay to (re)select and / or which detected relay to report to the network. For example, a WTRU may select and / or report relay WTRUs that support multipath relay services.

[0214] A WTRU may determine, based on the supported SLRB / LCH, which relay to (re)select and / or which detected relay to report to the network. For example, a WTRU may select and / or report relay WTRUs that support its established SLRB / LCH.

[0215] A WTRU may determine which relay to (re)select and / or which detected relay to report to the network, based on relay WTRUs that support dual connectivity. For example, a WTRU may prioritize selecting relay WTRUs that support dual connectivity.

[0216] A WTRU may determine which relay to (re)select and / or which detected relay to report to the network, based on relay WTRUs that support multipath within the cell and / or gNB (e.g., the same cell and / or gNB). For example, a WTRU (e.g., a remote WTRU) may prefer to select relay WTRUs that connect to the same cell and / or gNB as its serving cell and / or gNB.

[0217] A WTRU may determine which relay to (re)select and / or which discovered relay to report to the network based on relay WTRUs in the cell and / or gNB that have measured Uu RSRP above a threshold. For example, a WTRU may receive discovery messages from relay WTRUs that indicate a serving cell and / or gNB. A WTRU may perform measurements (e.g., Uu RSRP) of the serving cell and / or relay's gNB. The WTRU may then (for example,) prioritize a relay if the measured Uu RSRP is above a threshold. In some examples, a WTRU may prioritize a relay that has SD-RSRP above a threshold and the highest Uu RSRP. In another example, a WTRU may prioritize a relay WTRU with the highest SD-RSRP, where the serving cell and / or gNB's Uu RSRP is above a threshold. SD-RSRP and / or Uu RSRP thresholds may be (pre)configured.

[0218] A WTRU may determine which relay to (re)select and / or which detected relay to report to the network based on its distance to the gNB. For example, if a WTRU is (pre)configured to select a single-hop relay service, it may select and / or report relay WTRUs whose distance to the gNB is within a certain range. The range can be (pre)configured. Alternatively or additionally, if a WTRU is (pre)configured to select a multipath relay service, it may select and / or report relay WTRUs whose distance to the gNB is greater than or equal to a threshold (e.g., a (pre)configured threshold). If both relays meet the (pre)configured distance to the gNB condition, the WTRU may prefer one or more relay WTRUs that are closer to the network (e.g., shorter).

[0219] Figure 5 illustrates an exemplary system 500 that illustrates that remote WTRU 504 takes precedence over relay WTRU 502 associated with gNB 510 whose measured Uu RSRP is above a threshold. For example, as shown in Figure 5, if remote WTRU 504 is outside the coverage of gNB1 508, remote WTRU 504 may discover relay 1 502 and / or relay 2 506. The SD-RSRP of relay 2 506 may be greater than the SD-RSRP of relay 1 502. In the discovery message, relay 1 502 may indicate the ID of gNB2 510, and / or relay 2 506 may indicate the ID of gNB3 512. Remote WTRU 504 may perform Uu RSRP measurements of gNB2 510 and / or gNB3 512. As an addition or alternative, the remote WTRU 504 may determine that the Uu RSRP of gNB3 512 is below a threshold. The WTRU may then (for example,) preferentially select relay 1 502 for multipath connectivity with relay 1 502 and gNB2 510.

[0220] A WTRU may determine whether resource reselection should be performed. In the example, a WTRU may have multipath links to a gNB. One link may be a Uu link, and / or another may be a relay link. A relay link may satisfy one or more of the conditions for relay reselection (e.g., the WTRU detects an RLF with the current relay, the SL-RSRP is less than a threshold, and / or the WTRU receives a release message from the relay WTRU). Based on the WTRU's RRC status and / or Uu RSRP, the WTRU may determine whether relay reselection should be performed.

[0221] A WTRU may determine whether to perform a reselection based on its RRC status. For example, if the WTRU is in an RRC connected state and / or in an RRC inactive state, the WTRU may perform a relay reselection and / or report the set of relays detected to the network. For example, if the WTRU is in an RRC idle state, the WTRU may not perform a relay reselection and / or report the set of relays detected to the network.

[0222] A WTRU can determine whether relay reselection should be performed based on the Uu RSRP. For example, a WTRU may trigger relay reselection if the Uu RSRP is less than a threshold. A WTRU can be connected to a multipath relay. For example, a WTRU may trigger a switch to a singlepath relay if the Uu RSRP is below a threshold. In another example, a WTRU may trigger relay reselection if the Uu RSRP is greater than or equal to a threshold. For example, a WTRU can be connected to a singlepath relay. A WTRU may trigger a switch to a multipath relay if the Uu RSRP is greater than or equal to a threshold.

[0223] A WTRU may determine whether to perform relay reselection and / or report the detected set of relays to the network. A WTRU may connect to the gNB via the Uu and / or relay WTRU. A WTRU may detect that the current relay is no longer the preferred relay (e.g., the RSRP with the current relay is below a threshold). Based on the Uu RSRP, a WTRU may determine whether to perform relay reselection and / or report the status of the current relay to the network. A WTRU may report an event to the network if the Uu RSRP is above a threshold. For example, a WTRU may report an event to the network if it has good Uu connectivity to the network. In another example (e.g., other than the above), if the Uu RSRP is below a threshold, a WTRU may perform autonomous relay reselection. A WTRU may reselect a WTRU that supports single-path relaying.

[0224] Cell reselection may be performed for multipath relays. For example, a WTRU may trigger cell reselection. A WTRU may trigger cell reselection and / or report the set of cells detected to the network, or support the network in a handover procedure, for example. A WTRU may trigger cell reselection and / or report the set of cells detected to the network based on one or more of the following: the WTRU detects a relay with an SD-RSRP greater than or equal to a threshold; the WTRU detects a relay with an SD-RSRP that is offset greater than the SD-RSRP / SL-RSRP of the current relay; and / or the SL-RSRP / SD-RSRP of the current relay and / or the Uu-RSRP of the current cell are below a threshold.

[0225] A WTRU may trigger cell reselection and / or report the set of detected cells to the network based on the WTRU detecting a relay with an SD-RSRP above a threshold. For example, a WTRU may detect a relay with an SD-RSRP above a threshold. If the relay WTRU is in another cell and / or gNB, the WTRU may measure the Uu RSRP of the serving cell of the detected relay. The WTRU may then report the detected cell / gNB to the network. The WTRU may reselect the cell associated with the relay if, for example, the Uu RSRP of the current gNB is below a threshold and / or the WTRU detects a Uu RLF with the current gNB.

[0226] The WTRU may trigger cell reselection and / or report the set of detected cells to the network based on the detection of a relay whose SD-RSRP offset is greater than or equal to the current relay's SD-RSRP and / or SL-RSRP. For example, the WTRU may detect a relay whose SD-RSRP offset is greater than or equal to a threshold. For example, if the relay WTRU is in another cell and / or gNB, the WTRU may measure the Uu RSRP of the serving cell of the detected relay. The WTRU may then report the detected cell and / or gNB to the network. The WTRU may reselect the cell associated with the relay if, for example, the Uu RSRP of the current gNB is less than a threshold and / or the WTRU detects a Uu RLF with the current gNB.

[0227] The WTRU may trigger cell reselection and / or report the set of detected cells to the network based on whether the current relay's SL-RSRP / SD-RSRP and / or the current cell's Uu RSRP are below a threshold. For example, if the current relay's SD-RSRP and / or SL-RSRP are below a threshold, the WTRU may trigger relay reselection and / or cell selection to select a different relay and / or cell.

[0228] The WTRU may determine which cells should be prioritized and / or reported. In the example, the WTRU may trigger cell reselection and / or report the set of detected cells to the network in order to support the network in a handover procedure. The WTRU may determine which cells should be reselected and / or reported to the network based on one or more of the following: the cell WTRU supports multipath, and / or the cell / gNB has an SD-RSRP above a threshold in the measured SD-RSRP of the relays within the cell.

[0229] A WTRU may determine which cells should be re-selected and / or reported to the network based on the cell WTRUs that support multipath. For example, a WTRU (e.g., a remote WTRU) may prioritize selecting cells that support multipath. Additionally or alternatively, a WTRU may perform Uu RSRP and / or SD-RSRP measurements (e.g., both). The WTRU may then prioritize cells with relays where both Uu RSRP and SD-RSRP are above their respective thresholds.

[0230] A WTRU may determine which cell should be reselected and / or reported to the network based on whether the cell and / or gNB have an SD-RSRP above a threshold in the measured SD-RSRP of the relays within the cell. For example, a WTRU may receive discovery messages from relay WTRUs. Discovery messages may indicate a serving cell and / or gNB. A WTRU may perform a measurement (e.g., Uu RSRP) of the serving cell and / or relay's gNB. The WTRU may then (for example,) prioritize a cell if the measured SD-RSRP is above a threshold. In some examples, a WTRU may prioritize a cell that has a Uu RSRP above a threshold and the highest SD-RSRP of the relays within the cell. For example, a WTRU may prioritize a cell WTRU with the highest Uu RSRP when the SD-RSRP relay is above a threshold. SD-RSRP and / or Uu RSRP thresholds may be (pre)configured.

[0231] A relay WTRU may perform one or more discover transmissions. For example, a WTRU (e.g., a relay WTRU) may determine which type of discover-relay-service message to send, the resource pool for sending the discovery message, and / or one or more parameters of the discover-relay-service transmission. Additionally or alternatively, a WTRU may determine which type of discover-relay-service message to send, the resource pool for sending the discovery message, and / or one or more parameters of the discover-relay-service transmission based on one or more of the WTRU's measured Uu RSRP, relay load, and / or relay capacity.

[0232] A WTRU may receive configurations and / or conditions for one or more types of discover-relay-service messages (e.g., multipath vs. singlepath) via, for example, a SIB or a dedicated RRC. The conditions may include one or more of the following: Uu RSRP ranges for singlepath discoveries (e.g., minimum and maximum Uu RSRP), different min_Uu RSRPs for multipath discover-relay-service, relay capabilities (e.g., relay capabilities that may include supporting singlepath and / or multipath relay), and / or QoS (e.g., priority) and transmit resource pools for one or more types of discoveries messages.

[0233] The WTRU may then determine which type of discover-relay-service message to send based on one or more of the measured Uu RSRP, relay load, and / or the ability to support multipath and / or single-path relay. The WTRU may select a resource pool for sending discoveries based on the discoveries type. The WTRU may use (pre)configured QoS for discoveries to determine, for example, the sending parameters for discoveries messages.

[0234] The WTRU may, for example, then, indicate in the discovery message the discovery-relay-service type (e.g., single-path and / or multi-path), the Uu RSRP (e.g., Uu RSRP for the remote WTRU to perform relay selection), and / or the QoS of the discovery message (e.g., priority). The WTRU may, for example, then, perform discovery transmission.

[0235] A remote WTRU may perform one or more discover-relay-service transmissions. A WTRU (e.g., a remote WTRU) may determine whether to send a discover message and / or the type of discover-relay-service message (e.g., single-path discover or multipath discover) based on one or more of the following: its measured Uu RSRP, the reception of the SLRB configuration for multipath, and / or incoming data from a set of SLRB / LCHs into a buffer. A WTRU may perform relay selection and / or report a set of relay WTRUs to the network based on, for example, the supported relay services of the discovered relays, and the Uu RSRP of the remote WTRU and / or the Uu RSRP of the remote WTRU.

[0236] A WTRU may receive conditions (e.g., via RRC and / or SIB) for sending one or more discover-relay-service messages. A discover-relay-message may include one or more of the following: a maximum Uu RSRP for single-path discoveries, a range of Uu RSRPs for multipath discoveries (e.g., a minimum Uu RSRP and / or (different) maximum Uu RSRPs), a set of SLRBs / LCHs to trigger multipath discoveries, and / or a minimum Uu RSRP for relays per SLRB / LCH.

[0237] A WTRU may trigger a discovery transmission. For example, a WTRU may trigger a discovery transmission based on one or more of the following: the Uu threshold for sending a multipath discovery is met; it receives an SLRB / LCH configuration (e.g., an SLRB / LCH configuration that satisfies the configured conditions for multipath relay); and / or it receives SLRB / LCH data (e.g., SLRB / LCH data that satisfies the configured conditions for multipath relay). A WTRU may perform relaying of one or more response receptions. A WTRU may perform relay selection and / or select a set of relays to notify the network. For example, a WTRU may perform relay selection and / or select a set of relays that satisfy one or more of the following conditions (e.g., conditions): namely, that they support multipath, that they support an established SLRB / LCH, and / or that the relay's Uu RSRP is greater than or equal to a threshold (e.g., a threshold that may be based on the SLRB / LCH of a remote WTRU).

[0238] A relay WTRU may determine which set of discovered remote WTRUs should be reported to the network. Additionally or alternatively, the WTRU may determine which set of discovered relays should be reported to the network. A relay WTRU may indicate (e.g., send) information in its discovery message. A remote WTRU may indicate (e.g., send) its Uu connection status in its discovery service message. A WTRU may decide to send a discovery-relay-service message. A WTRU may determine whether a cell supports one or more relay services. A WTRU may determine whether to send a discovery-relay-service message based on instructions from the cell. A WTRU may determine whether to respond to (e.g., send) a remote WTRU. A WTRU may determine its load.

[0239] A WTRU (e.g., a first WTRU) may monitor one or more discovery messages. These discovery messages may be from one or more second WTRUs. The WTRU may, for example, determine a set of one or more second WTRUs based on the discovery messages. The WTRU may report this set of second WTRUs to the network, for example. The set of one or more second WTRUs may be based on their support type. The support type may include one or more of single-path and multi-path services. The WTRU may compare the second WTRU reference signal received power (RSRP) to a threshold. The WTRU may determine the support type based on the comparison of the second WTRU RSRP to the threshold. For example, if the second WTRU RSRP is below the threshold, the WTRU may determine the support type is single-path service. In another example, if the second WTRU RSRP is below the threshold, the WTRU may determine the support type is single-path service. The WTRU may determine the support type based on the connectivity status of the second WTRUs. WTRU can be compared to a second WTRU Quality of Service (QoS) threshold.

[0240] A WTRU (e.g., a relay WTRU) may receive configuration information. This configuration information may include one or more parameters. These one or more parameters may be necessary for the WTRU to operate as a mobile relay between networks. Additionally or alternatively, the parameters may include a first reference signal power (RSRP) threshold and / or a second RSRP threshold.

[0241] The WTRU may perform RSRP measurements. For example, the WTRU may perform RSRP measurements on a serving cell to determine the RSRP value. The WTRU may determine whether it supports one or more of single-path and multi-path operations. For example, the WTRU may determine whether it supports one or more of single-path and multi-path operations in a sidelink discovery message based on the RSRP value. The WTRU may indicate support for multi-path relay operations based on the RSRP value meeting a second RSRP threshold. Additionally or alternatively, the WTRU may indicate support for single-path relay operations based on the RSRP value meeting a first RSRP threshold. The WTRU may send a sidelink discovery message indicating support for one or more of single-path and multi-path relay operations. For example, the WTRU may send a sidelink discovery message indicating support for one or more of single-path and multi-path relay operations based on the RSRP value.

[0242] The parameters may include the relay load range. WTRU may indicate support for multipath relay operation based on, for example, whether the current relay load of the WTRU is below the relay load range. The parameters may include an indication for a first resource pool and / or a second resource pool. The first resource pool may be, for example, a resource pool for sending a first sidelink discovery message indicating support for single-path relay operation. The second resource pool may be a resource pool for sending a second sidelink discovery message, or an example indicating support for multipath relay operation. The sidelink discovery message may indicate an RSRP value. WTRU may indicate support for single-path relay operation when the RSRP value is greater than or equal to a first RSRP threshold. Additionally or alternatively, WTRU may indicate support for single-path relay operation when the RSRP value is less than a second RSRP threshold.

[0243] A WTRU may indicate support for multipath relay operation when the RSRP value is equal to or greater than a second RSRP threshold. A WTRU may, for example, send a report to the network based on the RSRP value. The report may indicate one or more second WTRUs. For example, the report may indicate one or more second WTRUs requesting single-path relay operation when the RSRP value meets the first RSRP threshold. Additionally or alternatively, the report may indicate that one or more second WTRUs are requesting multipath relay operation when the RSRP value meets the second RSRP threshold (e.g., equal to or greater than the second RSRP threshold).

[0244] Figure 6 illustrates an exemplary system 600 illustrating relay WTRUs 602, 606 that determine whether to send single-path discovery versus multipath discovery based on whether the measured Uu RSRP is above a threshold. For example, as shown in Figure 6, relay WTRUs 602 and / or 606 may receive a configuration (e.g., a configuration in the SIB and / or RRC) indicating whether to send a single-path discovery service message versus (e.g., and / or) a multipath discovery service message based on the Uu RSRP. The configuration may additionally or alternatively include a relay load for sending multipath discovery, and / or a resource pool for multipath discovery and / or single-path discovery. For example, the instruction on whether to send a single-path discovery versus (e.g., and / or) multipath discovery service message may additionally or alternatively be based on a relay load for sending multipath discovery and / or a resource pool for multipath discovery and / or single-path discovery. Relay WTRUs 602 and / or 606 may receive a configuration from the gNB 610. For example, relay WTRU602 may send a multipath discovery message if Uu RSRP is greater than Uu RSRP threshold 1 (e.g., a first threshold), and / or relay WTRU606 may decide (e.g., send) a single-path discovery message if Uu RSRP is between Uu RSRP threshold 1 (e.g., a first threshold) and Uu RSRP threshold 2 (e.g., a second threshold). Uu RSRP threshold 2 (e.g., a second threshold) may be used to indicate a coverage boundary. Relays WTRU602 and / or WTRU606 may measure Uu RSRP and / or check Uu RSRP conditions for multipath discovery and / or single-path discovery. Relays WTRU602 and / or WTRU606 may check relay load conditions for multipath discovery and / or single-path discovery. Relay WTRU602 and / or Relay WTRU606 may, for example, send single-path discovery messages and / or multi-path discovery messages in a (pre-configured) resource pool (for example, if certain conditions are met).For example, relay WTRU602 and / or relay WTRU606 may indicate the discovery type (e.g., single-path and / or multi-path) in their discovery message. Remote WTRU604 may send one or more solicitation messages for multi-path. For example, remote WTRU604 may send one or more solicitation messages for multi-path if its Uu RSRP is greater than Uu RSRP threshold 2 (e.g., second threshold), and / or remote WTRU608 may send one or more single-path solicitation messages if its Uu RSRP is less than Uu RSRP threshold 2 (e.g., second threshold) and greater than Uu RSRP threshold 3 (e.g., third threshold, not shown). Remote WTRU608 and remote WTRU604 may be the same WTRU and may, for example, move further away from or closer to gNB610. Relays WTRU602 and WTRU606 may be the same WTRU and may, for example, move further away from or closer to gNB610.

[0245] The processes and means described herein may be applied in any combination. Additionally or alternatively, the processes and means described herein may be applied to other wireless technologies and / or other services.

[0246] A WTRU may refer to user identification information, such as physical device identification information and / or subscription-related identification information (e.g., MSISDN, SIP URI, etc.). Additionally or alternatively, a WTRU may refer to application-based identification information (e.g., a username that may be used on an application-by-application basis).

[0247] The processes described above may be implemented, for example, in computer programs, software, and / or firmware embedded in computer-readable media for implementation by a computer and / or processor. Examples of computer-readable media include, but are not limited to, electronic signals (transmitted, for example, via wired and / or wireless connections) and / or computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, read-only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media (e.g., internal hard disks and removable disks), magneto-optical media, and / or optical media (e.g., CD-ROM discs and / or digital versatile disks (DVDs)). For example, a radio frequency transceiver for use in one or more of the following may be implemented using a processor associated with software: a WTRU, UE, terminal, base station, RNC, and / or any host computer.

Claims

1. A first wireless transmit / receive unit (WTRU) equipped with a processor, wherein the processor is Receive configuration information indicating parameters for operating as a WTRU-inter-network mobile relay, wherein the parameters include a first reference signal received power (RSRP) threshold and a second RSRP threshold. To determine the RSRP value, the RSRP of the serving cell is measured. Based on the RSRP value, it is determined whether the sidelink discovery message indicates support for one or more of single-path relay operations or multi-path relay operations, with support for multi-path relay operations being determined based on the RSRP value satisfying the second RSRP threshold, and support for single-path relay operations being determined based on the RSRP value satisfying the first RSRP threshold. The second WTRU receives the sidelink discovery message indicating support for one or more of the single-path relay operation or the multi-path relay operation. The first WTRU is configured as follows.

2. The first WTRU according to claim 1, wherein the parameter includes a relay load threshold, and the processor is configured to determine that support for the multipath relay operation is indicated based on the relay load of the first WTRU being less than the relay load threshold.

3. The aforementioned parameters are, A first resource pool for sending a first sidelink discovery message, wherein the first sidelink discovery message includes instructions for support relating to the single-path relay operation, A second resource pool for sending a second sidelink discovery message, wherein the second sidelink discovery message includes instructions relating to the multipath relay operation, The first WTRU according to claim 1, comprising:

4. The first WTRU according to claim 1, wherein the side link discovery message includes an indication of the RSRP value.

5. The first WTRU according to claim 1, wherein the processor is configured to determine that support for the single-pass relay operation is indicated when the RSRP value is greater than the first RSRP threshold.

6. The first WTRU according to claim 1, wherein the processor is configured to determine that support for the single-path relay operation is indicated when the RSRP value is less than the second RSRP threshold.

7. The first WTRU according to claim 1, wherein the processor is configured to determine that support for the multipath relay operation is indicated when the RSRP value is greater than the second RSRP threshold.

8. The first WTRU according to claim 1, wherein the processor is configured to determine in the sidelink discovery message that it supports the single-path relay operation and the multipath relay operation.

9. The first WTRU according to claim 1, wherein the processor is configured to send a report to the network when the RSRP value satisfies the first RSRP threshold, the report including instructions for one or more second WTRUs requesting the single-path relay operation.

10. The first WTRU according to claim 1, wherein the processor is configured to send a report to the network when the RSRP value satisfies the second RSRP threshold, the report including instructions for one or more second WTRUs requesting the multipath relay operation.

11. A method performed by a first wireless transmit / receive unit (WTRU), Receiving configuration information indicating parameters for operating as a WTRU-inter-network mobile relay, wherein the parameters include a first reference signal received power (RSRP) threshold and a second RSRP threshold. To determine the RSRP value, the RSRP of the serving cell is measured, Based on the RSRP value, it is determined whether the sidelink discovery message indicates support for one or more of the single-path relay operation or multi-path relay operation, wherein support for the multi-path relay operation is determined based on the RSRP value satisfying the second RSRP threshold, and support for the single-path relay operation is determined based on the RSRP value satisfying the first RSRP threshold. Sending the sidelink discovery message to the second WTRU indicating support for one or more of the single-path relay operation or the multi-path relay operation, Methods that include...

12. The method according to claim 11, wherein the parameter includes a relay load threshold, and the method comprises determining to indicate support for the multipath relay operation based on the relay load of the first WTRU being less than the relay load threshold.

13. The aforementioned parameters are, A first resource pool for sending a first sidelink discovery message, wherein the first sidelink discovery message includes instructions for support relating to the single-path relay operation, A second resource pool for sending a second sidelink discovery message, wherein the second sidelink discovery message includes instructions relating to the multipath relay operation, The method according to claim 11, including the method described in claim 11.

14. The method according to claim 11, wherein the side link discovery message includes an indication of the RSRP value.

15. The method according to claim 11, further comprising determining that if the RSRP value is greater than the first RSRP threshold, it indicates support for the single-pass relay operation.

16. The method according to claim 11, further comprising determining that if the RSRP value is less than the second RSRP threshold, it indicates support for the single-pass relay operation.

17. The method according to claim 11, further comprising determining that if the RSRP value is greater than the second RSRP threshold, it indicates support for the multipath relay operation.

18. The method according to claim 11, further comprising determining that the side link discovery message indicates support for the single-path relay operation and the multi-path relay operation.

19. The method according to claim 11, wherein the method comprises sending a report to the network when the RSRP value satisfies the first RSRP threshold, the report including instructions for one or more second WTRUs requesting the single-path relay operation.

20. The method according to claim 11, wherein the method comprises sending a report to the network when the RSRP value satisfies the second RSRP threshold, the report including instructions for one or more second WTRUs requesting the multipath relay operation.

21. The first WTRU according to claim 1, wherein the multipath relay operation includes a multihop relay operation.

22. The method according to claim 11, wherein the multipath relay operation includes a multihop relay operation.

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