EP4759060A1 - Resource selection or reselection for sidelink discontinuous reception operation on multi-hop wtru to wtru relays - Google Patents

Abstract

A wireless transmit/receive unit (WTRU) may determine that a sidelink (SL) logical channel is associated with an SL transmission to be relayed through a first RX WTRU to a second RX WTRU. The WTRU may determine a first SL discontinuous reception (DRX) configuration associated with the first RX WTRU and a second SL DRX configuration associated with the second RX WTRU. The first SL DRX configuration may indicate a first active time, and the second SL DRX configuration may indicate a second active time. Based on a priority value of the SL logical channel being lower than a threshold value, the WTRU may determine an SL resource for the SL transmission based on one or more of the first active time, the second active time, a relaying latency associated with the first RX WTRU, or a packet delay budget (PDB) associated with the SL logical channel.

Description

RESOURCE SELECTION OR RESELECTION FOR SIDELINK DISCONTINUOUS RECEPTION OPERATION ON MULTI-HOP WTRU TO WTRU RELAYS

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63/531 ,133, filed August 7, 2023 the contents of which is incorporated by reference herein.

BACKGROUND

[0002] Mobile communications using wireless communication continue to evolve. A fifth generation of mobile communication radio access technology (RAT) may be referred to as 5G new radio (NR). A previous (legacy) generation of mobile communication RAT may be, for example, fourth-generation (4G) long-term evolution (LTE). Wireless communication devices may establish communications with other devices and data networks, e.g., via an access network, such as a radio access network (RAN).

SUMMARY

[0003] Systems, methods, and instrumentalities are disclosed herein for determining a sidelink (SL) resource for an SL transmission.

[0004] In examples, a wireless transmit/receive unit (WTRU) may determine that an SL logical channel is associated with an SL transmission to be relayed through a first RX WTRU to a second RX WTRU. The WTRU may determine a first SL discontinuous reception (DRX) configuration associated with the first RX WTRU and a second SL DRX configuration associated with the second RX WTRU. The first SL DRX configuration may indicate a first active time, and the second SL DRX configuration may indicate a second active time. Based on a priority value of the SL logical channel being lower than a threshold value, the WTRU may determine an SL resource for the SL transmission based on one or more of the first active time, the second active time, a relaying latency associated with the first RX WTRU, or a packet delay budget (PDB) associated with the SL logical channel. The WTRU may send the SL transmission on the SL resource.

[0005] In examples, the first active time may be a first time period associated with a first starting time and a first ending time, and the second active time may be a second time period associated with a second starting time and a second ending time. The WTRU may determine an overlapping time period of the first time period and the second time period. The WTRU may determine an effective active time based on the overlapping time period and the relaying latency associated with the first RX WTRU. The WTRU may determine the SL resource within the effective active time. For example, the overlapping time period may start at a later one of the starting time of the first time period and the starting time of the second time period. The overlapping time period may end at an earlier one of the ending time of the first time period and the ending time of the second time period. The PDB may not exceed the effective active time. The WTRU may determine the SL resource via a resource reselection. The WTRU may perform the resource reselection based on a determination that a selected SL resource is outside the effective active time.

[0006] In examples, the WTRU may determine that data associated with one or more SL logical channels is to be included in the SL transmission relayed through the first RX WTRU to the second RX WTRU. The WTRU may be triggered to determine the SL resource if the WTRU determines that the data associated with the one or more SL logical channels is to be included in the SL transmission.

[0007] In examples, the WTRU may determine the SL resource via a resource reselection. The WTRU may perform the resource reselection based on a determination that a selected SL resource is outside the first active time.

[0008] In examples, the WTRU may establish a PC5 connection with the first RX WTRU. The WTRU may send, to the first RX WTRU, a message indicating that a PC5 connection associated with the first RX WTRU and the second RX WTRU is to be established.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG. 1 A is a system diagram illustrating an example communications system in which one or more disclosed embodiments may be implemented.

[0010] FIG. 1 B is a system diagram illustrating an example wireless transmit/receive unit (WTRU) that may be used within the communications system illustrated in FIG. 1A according to an embodiment.

[0011] FIG. 1 C is a system diagram illustrating an example radio access network (RAN) and an example core network (CN) that may be used within the communications system illustrated in FIG. 1 A according to an embodiment.

[0012] FIG. 1 D is a system diagram illustrating a further example RAN and a further example CN that may be used within the communications system illustrated in FIG. 1A according to an embodiment.

[0013] FIG. 2 illustrates an example of RLC channel configuration in V2X.

[0014] FIG. 3 illustrates an example user plane protocol stack for L2 WTRU to network relays.

[0015] FIG. 4 illustrates an example RLC channel configuration procedure in U2N relays. [0016] FIG. 5 illustrates an example architecture for L2 WTRU to WTRU relay.

[0017] FIG. 6 illustrates an example for different SL DRX configuration with two RX WTRUs (case #1).

[0018] FIG. 7 illustrates an example for different SL DRX configuration with two RX WTRUs (case #2).

[0019] FIG. 8 illustrates an example of an effective active time of the RX WTRU#2 (case #1).

[0020] FIG. 9 illustrates an example of an effective active time of the RX WTRU#2 (case #2).

[0021] FIG. 10 illustrates an example of an effective active time of the RX WTRU#2 (case #3).

[0022] FIG. 11 illustrates example criteria of an aligned SL DRX configuration.

[0023] FIG. 12 illustrates an example for determining an SL DRX active time based on buffering time.

[0024] FIG. 13 illustrates an example path (re-)selection based on an SL DRX of a relay WTRU.

DETAILED DESCRIPTION

[0025] FIG. 1A is a diagram illustrating an example communications system 100 in which one or more disclosed embodiments may be implemented. The communications system 100 may be a multiple access system that provides content, such as voice, data, video, messaging, broadcast, etc., to multiple wireless users. The communications system 100 may enable multiple wireless users to access such content through the sharing of system resources, including wireless bandwidth. For example, the communications systems 100 may employ 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), and the like.

[0026] As shown in FIG. 1A, the communications system 100 may include wireless transmit/receive units (WTRUs) 102a, 102b, 102c, 102d, a RAN 104/113, a ON 106/115, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, though it will be appreciated that the disclosed embodiments contemplate 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 wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 102d, any of which may be referred to as a “station” and/or a “ST A”, may be configured to transmit and/or receive wireless signals and may include a user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a cellular telephone, a personal digital assistant (PDA), a smartphone, a laptop, a netbook, a personal computer, a wireless sensor, a hotspot or Mi-Fi device, an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and/or other wireless devices operating in an industrial and/or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and/or industrial wireless networks, and the like. Any of the WTRUs 102a, 102b, 102c and 102d may be interchangeably referred to as a UE.

[0027] The communications systems 100 may also include a base station 114a and/or a base station 114b. Each of the base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks, such as the CN 106/115, the Internet 110, and/or the other networks 112. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a Node-B, an encode B, a Home Node B, a Home eNode B, a gNB, a NR NodeB, a site controller, an access point (AP), a wireless router, and the like. While the base stations 114a, 114b are each depicted as a single element, it will be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and/or network elements.

[0028] The base station 114a may be part of the 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), relay nodes, etc. The base station 114a and/or the base station 114b may be configured to transmit and/or receive wireless signals on one or more carrier frequencies, which may be referred to as a cell (not shown). These frequencies may be in licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide coverage for a wireless service to a specific geographical area that may be relatively fixed or that may change over time. The cell may further be divided into cell sectors. For example, the cell associated with the base station 114a may be divided into three sectors. Thus, in one embodiment, the base station 114a may include three transceivers, i.e., one for each sector of the cell. In an embodiment, the base station 114a may employ multiple-input multiple output (MIMO) technology and may utilize multiple transceivers for each sector of the cell. For example, beamforming may be used to transmit and/or receive signals in desired spatial directions.

[0029] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over an air interface 116, which may be any suitable wireless 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).

[0030] More specifically, as noted above, the communications system 100 may be a multiple access system and may employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. For example, the base station 114a in the RAN 104/113 and the WTRUs 102a, 102b, 102c may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may establish the air interface 115/116/117 using wideband CDMA (WCDMA). WCDMA may include communication protocols such as High-Speed Packet Access (HSPA) and/or Evolved HSPA (HSPA+). HSPA may include High-Speed Downlink (DL) Packet Access (HSDPA) and/or High-Speed UL Packet Access (HSUPA).

[0031] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface 116 using Long Term Evolution (LTE) and/or LTE-Advanced (LTE-A) and/or LTE-Advanced Pro (LTE-A Pro).

[0032] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR Radio Access, which may establish the air interface 116 using New Radio (NR).

[0033] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may implement LTE radio access and NR radio access together, for instance using dual connectivity (DC) principles. Thus, the air interface utilized by WTRUs 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., an eNB and a gNB).

[0034] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio 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), GSM EDGE (GERAN), and the like.

[0035] The base station 114b in FIG. 1 A may be a wireless router, Home Node B, Home eNode B, or access point, for example, and may utilize any suitable RAT for facilitating wireless connectivity in a localized area, such as a place of business, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a roadway, and the like. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish a picocell or femtocell. As shown in FIG. 1 A, the base station 114b may have a direct connection to the Internet 110. Thus, the base station 114b may not be required to access the Internet 110 via the CN 106/115.

[0036] The RAN 104/113 may be in communication with the CN 106/115, 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 of the WTRUs 102a, 102b, 102c, 102d. The data may have varying quality of service (QoS) requirements, such as differing throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, and the like. The CN 106/115 may provide call control, billing services, mobile location-based services, pre-paid calling, Internet connectivity, video distribution, etc., and/or perform high-level security functions, such as user authentication. Although not shown in FIG. 1A, it will be appreciated that the RAN 104/113 and/or the CN 106/115 may be in direct or indirect communication with other RANs that employ the same RAT as the RAN 104/113 or a different RAT. For example, in addition to being connected to the RAN 104/113, which may be utilizing a NR radio technology, the CN 106/115 may also be in communication with another RAN (not shown) employing a GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.

[0037] The CN 106/115 may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and/or the other networks 112. The PSTN 108 may include circuit- switched telephone networks that provide plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols, such as the transmission control protocol (TCP), user datagram protocol (UDP) and/or the internet protocol (IP) in the TCP/IP internet protocol suite. The networks 112 may include wired and/or wireless communications networks owned and/or operated by other service providers. For example, the networks 112 may include another CN connected to one or more RANs, which may employ the same RAT as the RAN 104/113 or a different RAT.

[0038] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communications system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks over different wireless links). For example, the WTRU 102c shown in FIG. 1A may be configured to communicate with the base station 114a, which may employ a cellular-based radio technology, and with the base station 114b, which may employ an IEEE 802 radio technology.

[0039] FIG. 1 B is a system diagram illustrating an example WTRU 102. As shown in FIG. 1 B, the WTRU 102 may include 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 source 134, a global positioning system (GPS) chipset 136, and/or other peripherals 138, among others. It will be appreciated that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment.

[0040] The processor 118 may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs) circuits, any other type of integrated circuit (IC), a state machine, and the like. The processor 118 may perform signal coding, data processing, power control, input/output processing, and/or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit/receive element 122. While FIG. 1 B depicts the processor 118 and the transceiver 120 as separate components, it will be appreciated that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0041] The transmit/receive element 122 may be configured to transmit signals to, or receive signals from, a base station (e.g., the base station 114a) over 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 an embodiment, the transmit/receive element 122 may be an emitter/detector configured to transmit and/or receive IR, UV, or visible light signals, for example. In yet another embodiment, the transmit/receive element 122 may be configured to transmit and/or receive both RF and light signals. It will be appreciated that the transmit/receive element 122 may be configured to transmit and/or receive any combination of wireless signals.

[0042] Although the transmit/receive element 122 is depicted in FIG. 1 B as a single element, 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 transmitting and receiving wireless signals over the air interface 116.

[0043] The transceiver 120 may be configured to modulate the signals that are to be transmitted by the transmit/receive element 122 and to demodulate the signals that are received by the transmit/receive element 122. As noted above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers for enabling the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11, for example.

[0044] The processor 118 of the WTRU 102 may be coupled to, and may receive user input data from, the speaker/microphone 124, the keypad 126, and/or the display/touchpad 128 (e.g., a liquid crystal display (LCD) display unit or organic light-emitting diode (OLED) display unit). 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, and store data in, any type of suitable memory, such as the non-removable memory 130 and/or the removable memory 132. 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, and store data in, memory that is not physically located on the WTRU 102, such as on a server or a home computer (not shown).

[0045] The processor 118 may receive power from the power source 134 and may be configured to distribute and/or control the power to the other components in the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power source 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, and the like.

[0046] The processor 118 may also be coupled to the 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 in lieu of, the information from the GPS chipset 136, the WTRU 102 may receive location information over the air interface 116 from a base station (e.g., base stations 114a, 114b) and/or determine its location based on the timing of the signals being received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information by way of any suitable locationdetermination method while remaining consistent with an embodiment.

[0047] The processor 118 may further be coupled to other peripherals 138, which may include one or more software and/or hardware modules that provide additional features, functionality and/or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an e-compass, a satellite transceiver, a digital camera (for photographs and/or video), 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 peripherals 138 may include one or more sensors, the sensors may be one or more of a gyroscope, an accelerometer, a hall effect sensor, a magnetometer, an orientation sensor, a proximity sensor, a temperature sensor, a time sensor; a geolocation sensor; an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, and/or a humidity sensor.

[0048] The WTRU 102 may include a full duplex radio for which transmission and reception of some or all of the signals (e.g., associated with particular subframes for both the UL (e.g., for transmission) and downlink (e.g., for reception) may be concurrent and/or simultaneous. The full duplex radio may include an interference management unit to reduce and or substantially eliminate self-interference via either hardware (e.g., a choke) or signal processing via a processor (e.g., a separate processor (not shown) or via processor 118). In an embodiment, the WRTU 102 may include a half-duplex radio for which transmission and reception of some or all of the signals (e.g., associated with particular subframes for either the UL (e.g., for transmission) or the downlink (e.g., for reception)).

[0049] FIG. 1 C is a system diagram illustrating the RAN 104 and the CN 106 according to an embodiment. As noted above, the RAN 104 may employ an E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0050] The RAN 104 may include eNode-Bs 160a, 160b, 160c, though it will be appreciated that the RAN 104 may include any number of eNode-Bs while remaining consistent with an embodiment. The eNode-Bs 160a, 160b, 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the eNode-Bs 160a, 160b, 160c may implement MIMO technology. Thus, the eNode-B 160a, for example, may use multiple antennas to transmit wireless signals to, and/or receive wireless signals from, the WTRU 102a.

[0051 ] Each of the eNode-Bs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and/or DL, and the like. As shown in FIG. 1 C, the eNode-Bs 160a, 160b, 160c may communicate with one another over an X2 interface.

[0052] The CN 106 shown in FIG. 1 C may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. While each of the foregoing elements is depicted as part of the CN 106, it will be appreciated that any of these elements may be owned and/or operated by an entity other than the CN operator.

[0053] The MME 162 may be connected to each of the eNode-Bs 160a, 160b, 160c in the RAN 104 via an S1 interface and may serve as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer activation/deactivation, selecting a particular serving gateway during an initial attach of the WTRUs 102a, 102b, 102c, and the like. The MME 162 may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as GSM and/or WCDMA.

[0054] The SGW 164 may be connected to each of the eNode Bs 160a, 160b, 160c in the RAN 104 via the S1 interface. The SGW 164 may generally route and forward user data packets to/from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions, such as anchoring user planes during inter- eNode B handovers, triggering paging when DL data is available for the WTRUs 102a, 102b, 102c, managing and storing contexts of the WTRUs 102a, 102b, 102c, and the like.

[0055] The SGW 164 may be connected to the PGW 166, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0056] The CN 106 may facilitate communications with other networks. For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional land-line communications devices. For example, the CN 106 may include, or may communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to the other networks 112, which may include other wired and/or wireless networks that are owned and/or operated by other service providers.

[0057] Although the WTRU is described in FIGS. 1 A-1 D as a wireless terminal, it is contemplated that in certain representative embodiments that such a terminal may use (e.g., temporarily or permanently) wired communication interfaces with the communication network.

[0058] In representative embodiments, the other network 112 may be a WLAN.

[0059] A WLAN in Infrastructure Basic Service Set (BSS) mode may have an Access Point (AP) for the BSS and one or more stations (STAs) associated with the AP. The AP may have an access or an interface to a Distribution System (DS) or another type of wired/wireless network that carries traffic in to and/or out of the BSS. Traffic to STAs that originates from outside the BSS may arrive through the AP and may be delivered to the STAs. Traffic originating from STAs to destinations outside the BSS may be sent to the AP to be delivered to respective destinations. Traffic between STAs within the BSS may be sent through the AP, for example, where the source STA may send traffic to the AP and the AP may deliver the traffic to the destination STA. The traffic between STAs within a BSS may be considered and/or referred to as peer-to- peer traffic. The peer-to-peer traffic may be sent between (e.g., directly between) the source and destination STAs with a direct link setup (DLS). In certain representative embodiments, the DLS may use an 802.11e DLS or an 802.11 z tunneled DLS (TDLS). A WLAN using an Independent BSS (I BSS) mode may not have an AP, and the STAs (e.g., all of the STAs) within or using the IBSS may communicate directly with each other. The IBSS mode of communication may sometimes be referred to herein as an “ad- hoc” mode of communication.

[0060] When using the 802.11 ac infrastructure mode of operation or a similar mode of operations, the AP may transmit a beacon on a fixed channel, such as a primary channel. The primary channel may be a fixed width (e.g., 20 MHz wide bandwidth) or a dynamically set width via signaling. The primary channel may be the operating channel of the BSS and may be used by the STAs to establish a connection with the AP. In certain representative embodiments, Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) may be implemented, for example in in 802.11 systems. For CSMA/CA, the STAs (e.g., every STA), including the AP, may sense the primary channel. If the primary channel is sensed/detected and/or determined to be busy by a particular STA, the particular STA may back off. One STA (e.g., only one station) may transmit at any given time in a given BSS.

[0061] High Throughput (HT) STAs may use a 40 MHz wide channel for communication, for example, via a combination of the primary 20 MHz channel with an adjacent or nonadjacent 20 MHz channel to form a 40 MHz wide channel.

[0062] Very High Throughput (VHT) STAs may support 20MHz, 40 MHz, 80 MHz, and/or 160 MHz wide channels. The 40 MHz, and/or 80 MHz, channels may be formed by combining contiguous 20 MHz channels. A 160 MHz channel may be formed by combining 8 contiguous 20 MHz channels, or by combining two non-contiguous 80 MHz channels, which may be referred to as an 80+80 configuration. For the 80+80 configuration, the data, after channel encoding, may be passed through a segment parser that may divide the data into two streams. Inverse Fast Fourier Transform (IFFT) processing, and time domain processing, may be done on each stream separately. The streams may be mapped on to the two 80 MHz channels, and the data may be transmitted by a transmitting STA. At the receiver of the receiving STA, the above described operation for the 80+80 configuration may be reversed, and the combined data may be sent to the Medium Access Control (MAC).

[0063] Sub 1 GHz modes of operation are supported by 802.11af and 802.11 ah. The channel operating bandwidths, and carriers, are reduced in 802.11 af and 802.11 ah relative to those used in 802.11 n, and 802.11 ac. 802.11 af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in the TV White Space (TVWS) spectrum, and 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non- TVWS spectrum. According to a representative embodiment, 802.11 ah may support Meter Type Control/Machine-Type Communications, such as MTC devices in a macro coverage area. MTC devices may have certain capabilities, for example, limited capabilities including support for (e.g., only support for) certain and/or limited bandwidths. The MTC devices may include a battery with a battery life above a threshold (e.g., to maintain a very long battery life).

[0064] WLAN systems, which may support multiple channels, and channel bandwidths, such as 802.11 n, 802.11 ac, 802.11 af, and 802.11 ah, include a channel which may be designated as the primary channel. The primary channel may have a bandwidth equal to the largest common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and/or limited by a STA, from among all STAs in operating in a BSS, which supports the smallest bandwidth operating mode. In the example of 802.11 ah, the primary channel may be 1 MHz wide for STAs (e.g., MTC type devices) that support (e.g., only support) a 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. If the primary channel is busy, for example, due to a STA (which supports only a 1 MHz operating mode), transmitting to the AP, the entire available frequency bands may be considered busy even though a majority of the frequency bands remains idle and may be available.

[0065] In the United States, the available frequency bands, which may be used by 802.11 ah, are from 902 MHz to 928 MHz. In Korea, the available frequency bands are from 917.5 MHz to 923.5 MHz. In Japan, the available frequency bands are from 916.5 MHz to 927.5 MHz. The total bandwidth available for 802.11 ah is 6 MHz to 26 MHz depending on the country code.

[0066] FIG. 1 D is a system diagram illustrating the RAN 113 and the CN 115 according to an embodiment. As noted above, the RAN 113 may employ an NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 113 may also be in communication with the CN 115.

[0067] The RAN 113 may include gNBs 180a, 180b, 180c, though it will be appreciated that the RAN 113 may include any number of gNBs while remaining consistent with an embodiment. The gNBs 180a, 180b, 180c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the gNBs 180a, 180b, 180c may implement MIMO technology. For example, gNBs 180a, 108b may utilize beamforming to transmit signals to and/or receive signals from the gNBs 180a, 180b, 180c. Thus, the gNB 180a, for example, may use multiple antennas to transmit wireless signals to, and/or receive wireless signals from, the WTRU 102a. In an embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation technology. For example, the gNB 180a may transmit multiple component carriers to the WTRU 102a (not shown). A subset of these component carriers may be on unlicensed spectrum while the remaining component carriers may be on licensed spectrum. In an embodiment, the gNBs 180a, 180b, 180c may implement Coordinated Multi-Point (CoMP) technology. For example, WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and/or gNB 180c).

[0068] The WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using transmissions associated with a scalable numerology. For example, the OFDM symbol spacing and/or OFDM subcarrier spacing may vary for different transmissions, different cells, and/or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using subframe or transmission time intervals (TTIs) of various or scalable lengths (e.g., containing varying number of OFDM symbols and/or lasting varying lengths of absolute time).

[0069] The gNBs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in a standalone configuration and/or a non-standalone configuration. In the standalone configuration, WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c without also accessing other RANs (e.g., such as eNode-Bs 160a, 160b, 160c). In the standalone configuration, WTRUs 102a, 102b, 102c may utilize one or more of gNBs 180a, 180b, 180c as a mobility anchor point. In the standalone configuration, WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using signals in an unlicensed band. In a non-standalone configuration WTRUs 102a, 102b, 102c may communicate with/connect to gNBs 180a, 180b, 180c while also communicating with/connecting to another RAN such as eNode-Bs 160a, 160b, 160c. For example, WTRUs 102a, 102b, 102c may implement DC principles to communicate with one or more gNBs 180a, 180b, 180c and one or more eNode-Bs 160a, 160b, 160c substantially simultaneously. In the non-standalone configuration, eNode-Bs 160a, 160b, 160c may serve as a mobility anchor for WTRUs 102a, 102b, 102c and gNBs 180a, 180b, 180c may provide additional coverage and/or throughput for servicing WTRUs 102a, 102b, 102c.

[0070] Each of the gNBs 180a, 180b, 180c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and/or DL, support of network slicing, dual connectivity, interworking between NR and E- UTRA, routing of user plane data towards User Plane Function (UPF) 184a, 184b, routing of control plane information towards Access and Mobility Management Function (AMF) 182a, 182b and the like. As shown in FIG. 1 D, the gNBs 180a, 180b, 180c may communicate with one another over an Xn interface.

[0071] The CN 115 shown in FIG. 1 D may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one Session Management Function (SMF) 183a, 183b, and possibly a Data Network (DN) 185a, 185b. While each of the foregoing elements are depicted as part of the CN 115, it will be appreciated that any of these elements may be owned and/or operated by an entity other than the CN operator.

[0072] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via an N2 interface and may serve as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, support for network slicing (e.g., handling of different PDU sessions with different requirements), selecting a particular SMF 183a, 183b, management of the registration area, termination of NAS signaling, mobility management, and the like. Network slicing may be used by the AMF 182a, 182b in order to customize CN support for WTRUs 102a, 102b, 102c based on the types of services being utilized WTRUs 102a, 102b, 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, services for machine type communication (MTC) access, and/or the like. The AMF 182 may provide a control plane function for switching between the RAN 113 and other RANs (not shown) that employ other radio technologies, such as LTE, LTE-A, LTE-A Pro, and/or non-3GPP access technologies such as WiFi.

[0073] The SMF 183a, 183b may be connected to an AMF 182a, 182b in the CN 115 via an N11 interface. The SMF 183a, 183b may also be connected to a UPF 184a, 184b in the CN 115 via an N4 interface. The SMF 183a, 183b may select and control the UPF 184a, 184b and configure the routing of traffic through the UPF 184a, 184b. The SMF 183a, 183b may perform other functions, such as managing and allocating UE IP address, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notifications, and the like. A PDU session type may be IP-based, non-IP based, Ethernetbased, and the like.

[0074] The UPF 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via an N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to packet- switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPF 184, 184b may perform other functions, such as routing and forwarding packets, enforcing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering downlink packets, providing mobility anchoring, and the like.

[0075] The CN 115 may facilitate communications with other networks. For example, the CN 115 may include, or may communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves as an interface between the CN 115 and the PSTN 108. In addition, the CN 115 may provide the WTRUs 102a, 102b, 102c with access to the other networks 112, which may include other wired and/or wireless networks that are owned and/or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, 102c may be connected to a local Data Network (DN) 185a, 185b through the UPF 184a, 184b via the N3 interface to the UPF 184a, 184b and an N6 interface between the UPF 184a, 184b and the DN 185a, 185b.

[0076] In view of Figures 1A-1 D, and the corresponding description of Figures 1A-1 D, one or more, or all, of the functions described herein with regard to one or more of: WTRU 102a-d, Base Station 114a-b, eNode-B 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMF 182a-b, UPF 184a-b, SMF 183a-b, DN 185a-b, and/or any other device(s) described herein, may be performed by one or more emulation devices (not shown). The emulation devices may be one or more devices configured to emulate one or more, or all, of the functions described herein. For example, the emulation devices may be used to test other devices and/or to simulate network and/or WTRU functions. [0077] The emulation devices may be designed to implement one or more tests of other devices in a lab environment and/or in an operator network environment. For example, the one or more emulation devices may perform the one or more, or all, functions while being fully or partially implemented and/or deployed as part of a wired and/or wireless communication network in order to test other devices within the communication network. The one or more emulation devices may perform the one or more, or all, functions while being temporarily implemented/deployed as part of a wired and/or wireless communication network. The emulation device may be directly coupled to another device for purposes of testing and/or may performing testing using over-the-air wireless communications.

[0078] The one or more emulation devices may perform the one or more, including all, functions while not being implemented/deployed as part of a wired and/or wireless communication network. For example, the emulation devices may be utilized in a testing scenario in a testing laboratory and/or a non-deployed (e.g., testing) wired and/or wireless communication network in order to implement testing of one or more components. The one or more emulation devices may be test equipment. Direct RF coupling and/or wireless communications via RF circuitry (e.g., which may include one or more antennas) may be used by the emulation devices to transmit and/or receive data.

[0079] Systems, methods, and instrumentalities are disclosed herein for determining a sidelink (SL) resource for an SL transmission.

[0080] In examples, a wireless transmit/receive unit (WTRU) may determine that an SL logical channel is associated with an SL transmission to be relayed through a first RX WTRU to a second RX WTRU. The WTRU may determine a first SL discontinuous reception (DRX) configuration associated with the first RX WTRU and a second SL DRX configuration associated with the second RX WTRU. The first SL DRX configuration may indicate a first active time, and the second SL DRX configuration may indicate a second active time. Based on a priority value of the SL logical channel being lower than a threshold value, the WTRU may determine an SL resource for the SL transmission based on one or more of the first active time, the second active time, a relaying latency associated with the first RX WTRU, or a packet delay budget (PDB) associated with the SL logical channel. The WTRU may send the SL transmission on the SL resource.

[0081] In examples, the first active time may be a first time period associated with a first starting time and a first ending time, and the second active time may be a second time period associated with a second starting time and a second ending time. The WTRU may determine an overlapping time period of the first time period and the second time period. The WTRU may determine an effective active time based on the overlapping time period and the relaying latency associated with the first RX WTRU. The WTRU may determine the SL resource within the effective active time. For example, the overlapping time period may start at a later one of the starting time of the first time period and the starting time of the second time period. The overlapping time period may end at an earlier one of the ending time of the first time period and the ending time of the second time period. The PDB may not exceed the effective active time. The WTRU may determine the SL resource via a resource reselection. The WTRU may perform the resource reselection based on a determination that a selected SL resource is outside the effective active time.

[0082] In examples, the WTRU may determine that data associated with one or more SL logical channels is to be included in the SL transmission relayed through the first RX WTRU to the second RX WTRU. The WTRU may be triggered to determine the SL resource if the WTRU determines that the data associated with the one or more SL logical channels is to be included in the SL transmission.

[0083] In examples, the WTRU may determine the SL resource via a resource reselection. The WTRU may perform the resource reselection based on a determination that a selected SL resource is outside the first active time.

[0084] In examples, the WTRU may establish a PC5 connection with the first RX WTRU. The WTRU may send, to the first RX WTRU, a message indicating that a PC5 connection associated with the first RX WTRU and the second RX WTRU is to be established.

[0085] Systems, methods, and instrumentalities are disclosed herein for determining, by a TX wireless transmit-receive unit (WTRU) (e.g., a source WTRU), a sidelink (SL) resource for a UE to UE (U2U) relay and/or for determining to trigger an SL resource (re-)selection based on an active time associated with a first RX WTRU and a second RX WTRU (e.g., an active time associated with the first RX WTRU and an active time associated with the second RX WTRU).

[0086] In examples, a WTRU (e.g., the TX WTRU) may receive configuration information associated with one or more SL logical channels associated with an SL transmission associated with the second RX WTRU (e.g., an SL transmission that is to be sent to the second RX WTRU via the first RX WTRU). The WTRU may receive an active time (e.g., an indication of a preferred active time) from the first RX WTRU and the second RX WTRU, for example, from the first RX WTRU, an active time associated with the first RX WTRU and, for the second RX WTRU, an active time associated with the second RX WTRU. The first RX WTRU may be, for example, a relaying WTRU. The second RX WTRU may be, for example, a target WTRU. The WTRU may configure or determine an SL discontinuous reception (DRX) configuration (e.g., an active time) for the first RX WTRU and/or the second RX WTRU. The WTRU may receive, for example, from the first RX WTRU, a latency associated with relaying (e.g., forwarding). The WTRU may determine an effective active time (e.g., a modified active time) associated with the second RX WTRU based on an active time associated with the second RX WTRU and the latency associated with relaying. For example, the effective active time for the second RX WTRU may be the active time of the second RX WTRU offset by the latency associated with relaying. In examples, the active time associated with the first RX WTRU may be a preferred active time received from the first RX WTRU, and the active time associated with the second RX WTRU may be a preferred active time received from the second RX WTRU.

[0087] The WTRU may determine one or more SL resources, for example, for SL data associated with the one or more SL logical channels, based on the active time associated with the first RX WTRU and the effective active time associated with the second RX WTRU. In examples, the WTRU may perform an SL resource selection (e.g., trigger the SL resource selection) based on the active time associated with the first RX WTRU and the effective active time associated with the second RX WTRU. The SL resource selection may include the determination of the one or more SL resources. The determined one or more SL resources may be used (e.g., by the first RX WTRU and/or the WTRU) to transmit the SL data associated with the one or more SL logical channels. For example, the WTRU may inform (e.g., send or indicate) the first RX WTRU and/or the second RX WTRU of the one or more SL resources, and the first RX WTRU may use the one or more SL resources to send (e.g., forward) the SL transmission including the SL data associated with the one or more SL logical channels to the second RX WTRU. The WTRU may trigger the SL resource selection, for example, on a condition that SL data is to be sent. For example, the WTRU may determine that a triggering condition to perform an SL resource selection has been satisfied and/or determine one or more SL resources based on the determination that the triggering condition to perform the SL resource selection has been satisfied. The WTRU may, for example, based on (e.g., upon) the triggering of the SL resource selection, determine one or more SL resources in the active time of the first RX WTRU and the effective active time of the second RX WTRU on a condition that SL data for transmission is associated with the one or more SL logical channels associated with the SL transmission associated with the second RX WTRU (e.g., the SL transmission that is to be sent to the second RX WTRU via the first RX WTRU).

[0088] The WTRU may establish, via the first RX WTRU, PC5 connections with the first RX WTRU and the second RX WTRU. The WTRU may receive configuration information indicating a priority threshold (e.g., reselection) for an SL logical channel of the one or more SL logical channels associated with the SL transmission associated with the second RX WTRU (e.g., to the second RX WTRU via the first RX WTRU). [0089] On a condition that an SL resource (re-)selection is triggered by the SL data associated with the one or more SL logical channels (e.g., the SL data that is from the one or more SL logical channels associated with the SL transmission associated with the second RX WTRU (e.g., to the second RX WTRU via the first RX WTRU)), the WTRU may determine whether to trigger the SL resource (re-)selection. For example, on a condition that a current (re-)selected SL resource is in the active time of the first RX WTRU and the effective active time of the second RX WTRU, the determination is not to trigger the SL resource (re-)selection and keep the current (re-)selected SL resource. On a condition that the current (re-)selected SL resource is outside of the active time of first RX WTRU, the determination is to trigger the SL resource (re-)selection. On a condition that the current (re-)selected SL resource is in the active time of the first RX WTRU and outside of the effective active time of the second RX WTRU, the determination is to trigger the SL resource (re-)selection on a condition that a priority value of the SL data is lower than the priority threshold (e.g., a configured threshold value) and a remaining packet delay budget (PDB) is within the effective active time of second RX WTRU, and the determination is not to trigger the SL resource (re- )selection and keep the current (re-)selected SL resource on a condition that the priority value of the SL data is equal to or higher than the priority threshold or the remaining PDB is not within the effective active time of second RX WTRU.

[0090] Systems, methods, and instrumentalities are disclosed herein for selecting, by a TX wireless transmit-receive unit (WTRU) (e.g., a source WTRU), a destination associated with a sidelink (SL) logical channel during performing a logical channel prioritization (LCP) procedure, for example, based on an active time associated with a first RX WTRU and a second RX WTRU (e.g., an active time associated with the first RX WTRU and an active time associated with the second RX WTRU).

[0091] In examples, a WTRU (e.g., the TX WTRU) may receive configuration information associated with one or more SL logical channels associated with an SL transmission that is to be sent to the second RX WTRU via the first RX WTRU. The WTRU may obtain a configured priority threshold value (e.g., reselection) for the one or more SL logical channels (e.g., for each SL logical channel of the one or more SL logical channels) associated with the SL transmission that is to be sent to the second RX WTRU via the first RX WTRU. The WTRU may receive, from the first RX WTRU, a latency associated with relaying (e.g., forwarding). The WTRU may obtain (e.g., receive or determine) an active time associated with the first RX WTRU and an active time (or an effective time) associated with the second RX WTRU. The first RX WTRU may be a relaying WTRU. The second RX WTRU may be a target WTRU. The WTRU may configure an SL discontinuous reception (DRX) configuration (e.g., an active time) for the first RX WTRU and/or the second RX WTRU. The WTRU may, for a selected SL grant, determine an SL destination and SL logical channel(s) to include in a medium access control (MAC) protocol data unit (PDU) associated the selected SL grant, for example, based on one or more of the active time associated with the first RX WTRU, the active time (or the effective time) associated with the second RX WTRU, or the configured priority threshold value. The WTRU may transmit SL data to the first RX WTRU, for example, using the selected SL grant.

[0092] For example, on a condition that SL data is available from an SL logical channel of the one or more SL logical channels associated with the SL transmission that is to be sent to the second RX WTRU via the first RX WTRU, the selected SL grant is within the active time of the first RX WTRU and the active time of the second RX WTRU, and a priority value of the one or more SL logical channels (e.g., the priority value of the SL logical channel) is below the configured priority threshold value, the WTRU may select a destination associated with the first RX WTRU, and first include data from SL logical channel(s) associated with the SL transmission associated with the second RX WTRU, for example, before other SL logical channels. On a condition that data is not available from the one or more SL logical channels associated with the SL transmission that is to be sent to the second RX WTRU via the first RX WTRU, the selected SL grant is not within the active time of the first RX WTRU and the active time of the second RX WTRU, and priority value(s) of the one or more SL logical channels (e.g., the priority value of the SL logical channel) is equal to or above the configured priority threshold value, the WTRU may select a destination having SL logical channel(s) with the highest priority and include SL data from SL logical channels according to an order of priority.

[0093] The WTRU may establish, via the first RX WTRU, PC5 connections with the first RX WTRU and the second RX WTRU. The active time associated with the first RX WTRU may be a preferred active time received from the first RX WTRU. The active time associated with the second RX WTRU may be a preferred active time received from the second RX WTRU.

[0094] Systems, methods, and instrumentalities are disclosed herein for determining, by a TX wireless transmit-receive unit (WTRU) (e.g., a source WTRU), an aligned sidelink (SL) discontinuous reception (DRX) configuration (e.g., one duration, SL DRX cycle) for RX WTRUs, for example, based on an end to end (E2E) packet delay budget (PDB) of SL data and/or a latency in relaying.

[0095] A WTRU (e.g., the TX WTRU) may receive an active time associated with a first RX WTRU and a second RX WTRU (e.g., an active time associated with the first RX WTRU and an active time associated with the second RX WTRU). The first RX WTRU may be a relaying WTRU, and the second RX WTRU may be a target WTRU. The WTRU may receive, from a base station, configuration information indicating a channel busy ratio (CBR)-dependent latency in relaying (e.g., a CBR-dependent maximum latency in relaying). The WTRU may determine a packet delay budget (PDB) (e.g., a minimum PDB) for an end to end (E2E) delivery based on quality of service (QoS) profiles (e.g., QoS profiles mapped to respective sidelink radio bearers (SLRBs) (e.g., QoS profiles mapped to each SLRB). The WTRU may determine aligned SL DRX configuration(s) for one or more (e.g., each) RX WTRU(s) (e.g., an aligned SL DRX configuration for the first RX WTRU and/or the second RX WTRU). In examples, the WTRU may select an SL DRX period and on duration such that (SL DRX period - on duration) < (minimum PDB for E2E delivery - maximum latency in relaying). The WTRU may transmit the aligned SL DRX configuration(s) to one or more (e.g., each) RX WTRU(s) (e.g., the first RX WTRU and/or the second RX WTRU).

[0096] The WTRU may establish, via the first RX WTRU, PC5 connections with the first RX WTRU and the second RX WTRU. The active time associated with the first RX WTRU may be a preferred active time received from the first RX WTRU, and the active time associated with the second RX WTRU may be a preferred active time received from the second RX WTRU.

[0097] Systems, methods, and instrumentalities are disclosed herein for determining, by a first RX wireless transmit-receive unit (WTRU) (e.g., a relay WTRU), an active time of a second RX WTRU (e.g., a target WTRU) and an updated/modified sidelink (SL) discontinuous reception (DRX) configuration based on a measured average buffering time change.

[0098] A first RX WTRU (e.g., a relay WTRU) may establish, via the first RX WTRU, PC5 connections with a TX WTRU (e.g., a source WTRU) and a second RX WTRU (e.g., a target WTRU), for example, a PC5 connection with the TX WTRU and a PC5 connection with the second RX WTRU. The first RX WTRU may receive an SL DRX configuration including a set of buffering times (e.g., on duration(s)) associated with one or more (e.g., each) active time(s) (e.g., a first active time). The first RX WTRU may measure a buffering time (e.g., an average buffering time), for example, as a time between a reception of a protocol data unit (PDU) and a transmission of the PDU (to the next hop). The first RX WTRU may obtain a configured threshold associated with a buffering time change (e.g., an average buffering time change). The first RX WTRU may perform a subsequent transmission based on the measured (e.g., average) buffering time. For example, the first RX WTRU may determine whether to use a second active time for the subsequent transmission based on the measured (e.g., average) buffering time and the configured threshold and perform the subsequent transmission based on the determination of whether to use the second active time for the subsequent transmission.

[0099] In examples, on a condition that the measured (e.g., average) buffering time changes above the configured threshold, the first RX WTRU may select the second active time (e.g., on duration) associated with the second RX WTRU based on the measured (e.g., average) buffering time and the received SL DRX configuration, send an updated/modified SL DRX configuration comprising the second active time to the second RX WTRU, and send the subsequent transmission to the second RX WTRU using the second active time.

[0100] Systems, methods, and instrumentalities are disclosed herein for determining, by a TX wireless transmit-receive unit (WTRU) (e.g., a source WTRU), a path (e.g., a direct path or an indirect path) based on an active time of a RX WTRU (e.g., a relay WTRU).

[0101] A WTRU (e.g., the TX WTRU) may establish, via a first RX WTRU, a PC5 connection with a RX WTRU. The RX WTRU may be a relay WTRU. The WTRU may send a sidelink (SL) discontinuous reception (DRX) configuration to the RX WTRU. The WTRU may receive a configured channel busy ratio (CBR) threshold for a path (re-)selection. The WTRU may determine whether to use an indirect path or a direct path (e.g., for an uplink (UL) transmission), based on an active time associated with the SL DRX configuration, for example, on a condition that data is triggered in one or more SL logical channels associated with the UL transmission via a split bearer over multipath (e.g., using Uu transmission(s) and/or SL transmission(s)).

[0102] In examples, the direct path may be determined to be used on a condition that the RX WTRU is outside an active time associated with the SL DRX configuration, a latency associated with an indirect path (e.g., an indirect transmission) does not satisfy an end to end quality of service (E2E QoS), and a measured CBR value is above (or equal to) the configured CBR threshold. The indirect path may be determined to be used on a condition that the RX WTRU is within the active time associated with the SL DRX configuration, the latency associated with the indirect path satisfies the E2E QoS, and the measured CBR value is below the configured CBR threshold. The WTRU may transmit the data (e.g., via UL or SL) based on the determined indirect or direct path.

[0103] A WTRU may carry on an SL DRX operation.

[0104] V2X (e.g., NR V2X) may support SL DRX for one or more of the following: unicast, groupcast, and/or broadcast. One or more parameters (e.g., parameters similar to parameters for Uu (e.g., a radio interface between UE and base station) such as on-duration, inactivity-timer, retransmission-timer, and/or cycle) may be defined for SL, for example, to determine an SL active time for SL DRX. During the SL active time, a WTRU may perform sidelink control information (SCI) monitoring for data reception (e.g., 1 ^st stage SCI on physical SL control channel (PSCCH) and 2^nd stage SCI on physical sidelink shared channel (PSSCH)). The WTRU may skip monitoring for the SCI for the data reception during SL DRX inactive time.

[0105] An active time of an RX WTRU (e.g., the SL active time of an RX WTRU) may include one or more times in which one or more of its applicable SL on-duration timer(s), SL inactivity-timer(s), or SL retransmission timer(s) (e.g., for any of unicast, groupcast, or broadcast) are running. In some examples, the slots associated with periodic transmissions by the TX WTRU (e.g., announced periodic transmissions by the TX WTRU) and/or the time in which a WTRU is expecting a CSI report, for example, following a CSI request (e.g., for unicast), may be considered as the active time of the RX WTRU. The time for a unicast link establishment procedure and/or the time for a PC5- radio resource control (RRC) reconfiguration with an initial SL DRX configuration procedure may be considered as the active time of the RX WTRU.

[0106] A TX WTRU (e.g., a source WTRU) may maintain a set of timers (e.g., a set of timers corresponding to the SL DRX timers in the RX WTRU(s) for each pair of source/destination L2 1 D (s) for unicast or destination L2 ID for groupcast/broadcast). When data is available for transmission (s) to one or more RX WTRU(s) configured with SL DRX, the TX WTRU may select resources, for example, considering the active time(s) of the RX WTRU(s) (e.g., determined by the timers maintained at the TX WTRU). [0107] SL DRX may be used for unicast. For unicast, SL DRX may be configured, for example, per pair of source Layer-2 identity (L2 ID) and destination L2 ID.

[0108] A WTRU may maintain a set of SL DRX timers for a direction (e.g., for each direction) per pair of source L2 ID and destination L2 ID. An SL DRX configuration for a pair of source/destination L2 IDs for a direction may be negotiated between the WTRUs, for example, in the access stratum (AS) layer. For a SL DRX configuration of one or more directions (e.g., each direction), where one WTRU is the TX WTRU and the other is the RX WTRU, one or more of the following may apply: the RX WTRU may send assistance information (e.g., including one or more of the following: its desired SL on-duration timer, an SL DRX start offset, and SL DRX cycle) to the TX WTRU and the mode 2 TX WTRU may use it to determine the SL DRX configuration for the RX WTRU; the TX WTRU, e.g., in RRCJDLE/RRCJNACTIVE/Out of Coverage (OOC), or in an RRC_CONNECTED state and using mode 2 resource allocation, may determine the SL DRX configuration for the RX WTRU (e.g., regardless of whether assistance information is provided or not); for a TX WTRU (e.g., a source WTRU) in an RRC_CONNECTED state and using mode 1 resource allocation, the SL DRX configuration for the RX WTRU may be determined by a base station (e.g., the serving gNB of the TX WTRU); the TX WTRU may send the SL DRX configuration to be used by the RX WTRU, to the RX WTRU; the RX WTRU may accept or reject the SL DRX configuration.

[0109] In examples, when the TX WTRU is in an RRC_CONNECTED state and using mode 1 resource allocation, the TX WTRU may report the received assistance information or the received SL DRX configuration reject information to a base station (e.g., its serving gNB supporting SL DRX) and may send the SL DRX configuration to the RX WTRU, for example, upon receiving the SL DRX configuration in dedicated RRC signaling from the gNB. When the RX WTRU is in an RRC_CONNECTED state and using mode 1 resource allocation, the RX WTRU may report the received SL DRX configuration to a base station (e.g., its serving gNB supporting SL DRX), for example, for alignment(s) of the Uu and SL DRX configurations.

[0110] One or more of SL on-duration timer(s), SL inactivity-timer(s), SL HARQ RTT timer(s), and/or SL HARQ retransmission timer(s) may be supported in unicast. SL HARQ RTT timer(s) and/or SL HARQ retransmission timer(s) may be maintained per SL process, for example, at the RX WTRU. An SL HARQ RTT timer value may be derived from the retransmission resource timing when SCI indicates more than one transmission resources, for example, in addition to (pre)configured values for one or more (e.g., each) of these timers. An SL HARQ RTT timer may be set to different values, for example, to support both HARQ enabled and HARQ disabled transmissions.

[0111] SL DRX medium access control (MAC) control element (CE) may be introduced for an SL DRX operation (e.g., in unicast only). [0112] An example logical channel prioritization (LCP) procedure may be implemented. A MAC entity may (e.g., for each SCI corresponding to a new transmission), if sl-BWP-DiscPoolConfig or sl-BWP- DiscPoolConfigCommon is not configured, select a destination associated to one of unicast, groupcast and broadcast, that is in the SL active time for the SL transmission occasion if SL DRX is applied for the destination, and having at least one of the MAC CE and the logical channel with the highest priority, among the logical channels that satisfy one or more (e.g., all) of the following conditions and MAC CE(s), if any, for the SL grant associated to the SCI:SL data is available for transmission; SBj > 0, in case there is one or more (e.g., any) logical channel having SBj > 0; sl-configuredGrantType1 Allowed, if configured, is set to true in case the SL grant is a Configured Grant Type 1; and sl-AllowedCG-List, if configured, includes the configured grant index associated to the SL grant; and/or sl-HARQ-FeedbackEnabled is set to disabled, if PSFCH is not configured for the SL grant associated to the SCI. If multiple destinations have the logical channels satisfying one or more (e.g., all) conditions above with the same highest priority or if multiple destinations have either the MAC CE and/or the logical channels satisfying all conditions above with the same priority as the MAC CE, which destination is selected among them may be determined.

[0113] An RLC channel configuration procedure in V2X may be used.

[0114] Vehicle-to-everything (V2X) (e.g., NR V2X) may support configuration procedure(s) for one or more of unicast, groupcast, and/or broadcast. In one or more (e.g., all) cases, a TX WTRU may determine an SL bearer configuration (e.g., one or more of packet data convergence protocol (PDCP), radio link control (RLC), MAC, etc configuration parameters), for example, from the QoS profile of a QoS flow initiated by the upper layers of the TX WTRU.

[0115] Determination of the bearer configuration may depend on, for example, the RRC state of the TX WTRU. When the TX WTRU is in an RRCJDLE/RRCJNACTIVE state, or out of network coverage (OOC), the WTRU may obtain the bearer configuration to use from system information block (SIB) or preconfiguration respectively. The SI B/preconfiguration may contain a list of bearer configurations (e.g., an exhaustive list of bearer configurations to be used for each QoS profile). If a QoS profile is not contained in the SIB/preconfiguration, the WTRU may use a default bearer configuration and/or map that QoS flow to the default bearer. For RRC_CONNECTED WTRU(s), the WTRU(s) may send the QoS profile of the QoS flow to the network (e.g., when the flow is initiated) and may receive the bearer configuration for the QoS flow, for example, from dedicated RRC signaling.

[0116] In mode 1 , the network may manage the scheduling of the resources to the TX WTRU (e.g., so that the latency requirements of each transmission are met). In mode 2, since the WTRU performs the scheduling, managing the latency may be built into a resource selection procedure. For example, when data triggers a resource selection procedure, the WTRU may select resource(s) with a resource selection window (e.g., a resource selection window defined by the PDB of the highest priority data available for transmission). This way, the latency requirements associated with that data may be met. The network may not be involved in defining the PDB (e.g., in the logical channel), for example, since the PDB may be determined based on the QoS profile (e.g., known to the TX WTRU from the QoS profile). FIG. 2 illustrates an example of an RLC channel configuration in V2X.

[0117] An RLC channel configuration procedure in user-to-network (U2N) relays may be used. FIG. 3 shows an example user plane protocol stack for L2 WTRU(s) to network relays.

[0118] With Uu (e.g., normal Uu), a WTRU may receive bearer configuration(s) from the network, for example, in dedicated RRC signaling. In some examples, for WTRU to network relays, the network may configure (e.g.., need to configure) not only the end-to-end service data adaptation protocol (SDAP) and PDCP to a remote WTRU, but also the sidelink relay adaptation protocol (SRAP) at the remote WTRU and the relay WTRU, and the RLC (and layer(s) below RLC at the remote WTRU (e.g., MAC/PHY) and below). Configuration may be performed by the network using dedicated radio resource control (RRC) signaling, for example, since the remote WTRU (eg., apart from communicating to the network via a relay) may be treated like a normal WTRU in Uu. For example, the remote WTRU may receive its data radio bearer (DRB) configuration using dedicated signaling (e.g., a RRCReconfiguration message), for example, like it does in Uu, except that it is received via a relayed signaling radio bearer (SRB).

[0119] In WTRU to network relays, the network may configure (e.g., need to configure) the adaptation layer (e.g., SRAP). The SRAP at the relay WTRU may handle the multiplexing of PC5 RLC channel(s) to Uu RLC channels (in uplink) and vice versa (in downlink). For example, the network may multiplex one or more PC5-RLC channels in uplink to the same Uu RLC channel. Based on the mapping, the adaptation layer may perform the routing, for example, upon the reception of packets at the relay WTRU.

[0120] For WTRU to network relays (e.g., and specifically for the transmission(s) on SL), the remote WTRU may be in mode 2 (e.g., by definition). For UL transmission(s), the latency associated with a remote WTRU’s transmission(s) may include (e.g., consist of) an SL part and a Uu part. The network may control the latency on the Uu part, and the WTRU (e.g., through resource selection) may control the SL part. Some coordination(s) may be used or needed (e.g., given the network controls the latency on the Uu part and the WTRU controls the SL part) so that the sum of the latencies meets the PDB associated with the packet. For example, the PDB associated to the packet may give the end-to-end latency, and, in some examples, may not be used for determining the resource selection window (e.g., as it did in V2X). To do so, the network may configure the PDB split (e.g., namely, the network may provide the remote WTRU, for each SL LCH which is relayed by the relay, a PDB that is used for the resource selection procedure in mode 2). FIG. 4 illustrates an example RLC channel configuration procedure in U2N relays. [0121] WTRU to WTRU relays may be used in one or more examples herein. FIG. 5 illustrates an example architecture for an L2 WTRU to WTRU relay. In WTRU-to-WTRU relays, one or more (e.g., any) of the WTRUs involved (e.g., source WTRU(s), destination WTRU(s), and relay(s)) may be in coverage or out of coverage, and may also be in any RRC state.

[0122] In examples (e.g., the current 3GPP specification), a TX WTRU (e.g., a source WTRU) may determine an SL DRX configuration associated with an RX WTRU. The SL DRX configuration may include one or more parameters related to SL active time (e.g., on duration time, SL DRX cycle, etc.). During a configured SL active time, the RX WTRU may perform SCI monitoring for an SL data reception. In some examples, the RX WTRU may skip monitoring for the SL data reception during an SL DRX cycle outside the configured SL active time (e.g., inactive time).

[0123] In a U2U relay operation, a source WTRU (e.g., a TX WTRU) may establish link(s) (e.g., a PC5 unicast link) with RX WTRU#1 (e.g., a relay WTRU) and RX WTRU#2 (e.g., a target WTRU) via the RX WTRU#1. The RX WTRU#1 may perform an SL data relaying operation from the source WTRU to the target WTRU (e.g., from the TX WTRU to the RX WTRU#2). If multiple RX WTRUs (e.g., the RX WTRU#1 and the RX WTRU#2) are associated with different SL DRX configurations, latency(ies) (e.g., addition latency(ies) such as latency(ies) for or due to different SL DRX configuration(s), latency(ies) in relaying, etc.) may occur in some instances. The source WTRU may select an SL resource in the active time of both the RX WTRU#1 and the RX WTRU #2 or align the SL DRX configurations for RX WTRUs, for example, to avoid such latency(ies). FIG. 6 illustrates an example for different SL DRX configurations associated with two RX WTRUs (Case #1). FIG. 6 shows a link 602 as a first link (e.g., link #1) and a link 604 as a second link (e.g., link 2). The first link and the second link may be associated with different SL DRX configurations. In FIG. 6, for example, a first SL DRX configuration 606 (SL DRX configuration #1) may be used in association with Link 1 , and a second SL DRX configuration 608 (e.g., SL DRX configuration #2) may be used in association with Link 2. Latency(ies) may occur on the link 602. FIG. 7 illustrates an example for different SL DRX configurations with two RX WTRUs (Case #2). FIG. 7 shows a link 702 as a first link (e.g., link #1) and a link 704 as a second link (e.g., link 2). The first link and the second link may be associated with different SL DRX configurations. In FIG. 7, for example, a first SL DRX configuration 706 (e.g., SL DRX configuration #1) may be used in association with Link 1, and a second SL DRX configuration 708 (e.g., SL DRX configuration #2) may be used in association with Link 2. Latency(ies) may occur on the link 704.

[0124] Latency(ies) may occur on one or more of the first link or the second link. For example, in case #1, latency(ies) may occur on link 1 (e.g., the link between a source WTRU (e.g., a TX WTRU) and a U2U relay WTRU). In case #2, latency(ies) may occur on link 2 (e.g., the link between a U2U relay WTRU and a target WTRU).

[0125] Resource selection(s) and/or resource reselection(s) aassociated with an U2U relay operation may be performed. For example, a TX WTRU (e.g., a source WTRU) may determine an SL resource for an U2U relay operation and/or determine to trigger an SL resource (re)selection based on the active time of the RX WTRU#1 and/or the active of the RX WTRU#2.

[0126] An example resource selection procedure may be used. A TX WTRU (e.g., a source WTRU) may establish PC5 connections with RX WTRU#1 (e.g., a relay WTRU) and RX WTRU#2 (a target WTRU) via the RX WTRU#1 . In examples, the WTRU may establish a PC5 connection with the first RX WTRU. The WTRU may send, to the first RX WTRU, a message indicating that a PC5 connection associated with the first RX WTRU and the second RX WTRU is to be established. For example, when SL data is triggered from the TX WTRU and the triggered SL data of an SL logical channel (e.g., according to a configuration) is associated with the RX WTRU#1 and the RX WTRU#2, the TX WTRU may indicate to the RX WTRU#1 that a link (e.g., a PC5) with the RX WTRU#2 for data relaying is to be established. For example, an indication of WTRU to WTRU relay (e.g., the PC5 connection may be established with first RX WTRU and second RX WTRU).

[0127] The TX WTRU may be configured with one or more SL logical channels associated with SL transmission to the RX WTRU#2 via the RX WTRU#1. In examples, the TX WTRU may determine that an SL logical channel is associated with an SL transmission to be relayed through a first RX WTRU to a second RX WTRU.

[0128] The TX WTRU may be configured with a (e.g., one) priority threshold (e.g., a threshold value associated with a resource reselection) for a SL logical channel (e.g., each of the SL logical channels) associated with the SL transmission to the RX WTRU#2 via the RX WTRU#1 .

[0129] The TX WTRU may receive preferred active time from RX WTRU#1 and RX WTRU#2. The TX WTRU may configure an SL DRX configuration (e.g., active time) for the RX WTRU#1 and RX WTRU#2. In examples, the TX WTRU may determine a first SL DRX configuration associated with the first RX WTRU and a second SL DRX configuration associated with the second RX WTRU. The first SL DRX configuration may indicate a first active time, and the second SL DRX configuration may indicate a second active time.

[0130] The TX WTRU may receive a latency in relaying (e.g., forwarding), for example, from the RX WTRU#1. The TX WTRU may determine an effective active time (e.g., an effective active time of the RX WTRU#2 as the active time of RX WTRU#2 offset in time by the latency of relaying). If triggering (e.g., upon triggering) SL resource selection(s), the TX WTRU may determine one or more SL resources within the active time of RX WTRU#1 and the effective active time if SL data for transmission is associated with the one or more SL logical channels associated with the SL transmission to the RX WTRU#2 via the RX WTRU#1.

[0131] Resource (re-)selection checking may be performed. In examples, based on a priority value of the SL logical channel being lower than a threshold value, the WTRU may determine an SL resource for the SL transmission based on one or more of the first active time, the second active time, a relaying latency associated with the first RX WTRU, or a PDB associated with the SL logical channel. The TX WTRU may determine whether or not to trigger the SL resource reselection, for example, if SL resource (re-)selection is triggered by an SL data and the SL data from the configured one or more SL logical channels associated with the SL transmission to the RX WTRU#2 via the RX WTRU#1 as one or more of the following: if the (re-elected resource is within the active time of RX WTRU#1 and effective active time of RX WTRU#2, the TX WTRU may keep the current SL resource. If the (re-)selected resource is outside of the active time of RX WTRU#1 , the WTRU (e.g., the TX WTRU) may trigger the resource (re-)selection; if the (re-)selected resource is within the active time of the RX WTRU#1 and outside the effective active time of the RX WTRU#2, the WTRU may trigger the resource (re-)selection or keep the current SL resource. For example, if the priority value of the SL data is lower than the configured threshold value and the remaining PDB is within the effective active time of RX WTRU 2, the WTRU may trigger the resource (re-)selection. If the priority value of the SL data is not lower than the configured threshold value or the remaining PDB is not within the effective active time of RX WTRU 2, the WTRU may keep the current SL resource.

[0132] LCP enhancements associated with a U2U relay may be made. For example, a TX WTRU (e.g., a source WTRU) may select a destination associated with an SL logical channel during performing an LCP procedure based on the active time(s) of multiple RX WTRUs (e.g., RX WTRU#1 and RX WTRU#2).

[0133] A TX WTRU (e.g., a source WTRU) may establish PC5 connections with the RX WTRU#1 (e.g., a relay WTRU) and the RX WTRU#2 (e.g., a target WTRU) via the RX WTRU#1 . The TX WTRU may be configured with one or more SL logical channels associated with an SL transmission to the RX WTRU#2 via the RX WTRU#1 . The TX WTRU may be configured with a priority threshold for an SL logical channel (e.g., a priority threshold for each of the SL logical channels) associated with the SL transmission to the RX WTRU#2 via the RX WTRU#1 . The TX WTRU may receive a latency in relaying (e.g., forwarding), for example, from the RX WTRU#1 . The TX WTRU may obtain (e.g., receive or determine) preferred active time(s) from the RX WTRU#1 and the RX WTRU#2. The TX WTRU may configure SL DRX configuration(s) (e.g., active time) for the RX WTRU#1 and RX WTRU#2. The TX WTRU may, for a selected SL grant, determine an SL destination and one or more SL logical channels to include in the MAC PDU for the grant as one or more of the following: if data is available from one of the SL logical channels associated with the SL transmission to RX WTRU#2 via RX WTRU#1, and the selected SL grant is within the active time of both the RX WTRU#1 and RX WTRU#2, and the priority value of the one or more SL logical channels is below the configured priority threshold value, the TX WTRU may select a destination associated with the RX WTRU#1, and first include data from SL logical channel(s) associated with the SL transmission to the RX WTRU#2 before other SL logical channels; otherwise, the TX WTRU may select the destination having the SL logical channel(s) with the highest priority and include SL data from the SL logical channels in order of priority. The TX WTRU may transmit the SL data to the RX WTRU#1 using the selected grant.

[0134] SL DRX configuration alignment may be based on a PDB and/or a latency in relaying. For example, a TX WTRU (e.g., a source WTRU) may determine an aligned SL DRX configuration (e.g., on duration, SL DRX cycle) for RX WTRUs. The aligned SL DRX configuration may be determined based on E2E PDB of SL data and/or latency(ies) in relaying.

[0135] A TX WTRU (e.g., a source WTRU) may establish PC5 connections with RX WTRU#1 (e.g., a relay WTRU) and RX WTRU#2 (e.g., a target WTRU) via the RX WTRU#1 . The TX WTRU may receive a preferred active time from the RX WTRU#1 and a preferred active time from the RX WTRU#2, respectively. The TX WTRU may be configured with a CBR-dependent maximum latency in relaying, for example, by the network. The TX WTRU may determine a minimum PDB for E2E delivery, for example, based on or from the QoS profiles mapped to one or more (e.g., each) sidelink radio bearers (SLRBs). The TX WTRU may determine aligned SL DRX configuration(s) for a RX WTRU (e.g., each of the RX WTRUs) using one or more of the following conditions: the TX WTRU may select a SL DRX period and on duration, for example, such that the following is satisfied, (SL DRX period - on duration) < (minimum PDB for E2E delivery - maximum latency in relaying). The TX WTRU may transmit the aligned SL DRX configuration(s) to a RX WTRU (e.g., each of the RX WTRUs).

[0136] An active time may be determined based on buffering time. For example, an RX WTRU (e.g., a relay WTRU) may determine an active time of the RX WTRU (e.g., a target WTRU) and a different (e.g., new or modified) SL DRX configuration based on a measured average buffering time change.

[0137] A WTRU (e.g., a relay WTRU such as RX WTRU#1) may establish PC5 connections with a TX WTRU (e.g., a source WTRU) and RX WTRU#2 (e.g., a target WTRU) via the RX WTRU#1 . The WTRU may receive an SL DRX configuration comprising a set of buffering time associated with one or more (e.g., each) active time (e.g., on duration). The WTRU may measure an averaged buffering time as the time between reception of a PDU and transmission of that PDU to the next hop. The WTRU may be configured with a threshold for an average buffering time change. If the measured average buffering time change(s) is above the configured threshold, the WTRU may select the active time (e.g., on duration) associated with the RX WTRU#2 based on the measured buffering time and the received SL DRX configuration, send the different SL DRX configuration (e.g., the new SL DRX configuration or the updated/modified SL DRX configuration) to the RX WTRU 2, and/or perform subsequent transmission(s) to the RX WTRU 2 based on the different active time (e.g., the new active time or the updated/modified active time).

[0138] Path selection may be performed based on SL DRX for U2N relay(s). For example, a TX WTRU (e.g., a source WTRU) may determine a path (e.g., a direct path or an indirect path) based on the active time of an RX WTRU (e.g., a relay WTRU).

[0139] A TX WTRU (e.g., a source WTRU) may establish PC5 connections with RX WTRU#1 (e.g., a relay WTRU). The TX WTRU may configure an SL DRX configuration to the RX WTRU. The TX WTRU may be configured with a CBR threshold for a path (re-)selection. The TX WTRU may, for example, upon triggering data (e.g., a new data) in one or more SL logical channels associated with uplink transmission via a split bearer over multipath (e.g., using Uu transmission or SL transmission), determine an indirect path or a direct path for the uplink transmission: the TX WTRU may determine the direct path, if the RX WTRU#1 is outside the active time, and if the latency of the indirect transmission does not satisfy E2E QoS, and if the measured CBR value is above the configured CBR threshold. The TX WTRU may determine the indirect path, if the RX WTRU#1 is within active time, and if the latency of the indirect transmission satisfies the E2E QoS, and if the measured CBR value is below the configured CBR threshold. The TX WTRU may transmit the data via the uplink or SL based on the determined path.

[0140] One or more of the following aspects may be applicable to one or more examples herein.

[0141] In one or more examples herein, U2U relay with two RX WTRUs may be used for simplicity. These examples may be applicable to other scenarios with more than two RX WTRUs. For example, one or more examples herein may be applied and/or extended to a scenario for N multiple RX WTRU#N (N > 2) with multi-hop U2U (N > 2) relays.

[0142] A source WTRU (e.g., a TX WTRU) may be notified (e.g., know) one or more (e.g., all) RX WTRU’s desired SL DRX configurations, for example, via SL WTRU assistance information. In examples, on a condition or given that a source WTRU (e.g., a TX WTRU) may learn one or more (e.g., all) RX WTRUs’ desired SL DRX configurations (e.g., on duration, cycle of SL DRX) via the SL WTRU assistance information, the source WTRU may consider the received desired SL DRX configuration(s), for example, when the source WTRU determines the SL DRX for an RX WTRU (e.g., when the source WTRU determines the SL DRX for an RX WTRU, received desired SL DRX configuration considered).

[0143] One or more SL logical channels may be configured.

[0144] A TX WTRU (e.g., a source WTRU) may be configured with SL bearer mapping, for example, by a SRAP sublayer. In examples, when the TX WTRU (e.g., the source WTRU) is configured with SL bearer mapping by a SRAP sublayer, the SRAP sublayer may perform SL bearer mapping end-to-end U2U bearers. For example, a PC5 SRAP sublayer at an L2 U2N remote WTRU may support UL bearer mapping between L2 U2N remote WTRU end-to-end Uu radio bearers and/or egress PC5 relay RLC channels. The PC5-SRAP sublayer may perform bearer mapping and/or data multiplexing end-to-end radio bearers (e.g., SRBs or DRBs) of WTRUs (e.g., the source WTRU to RX WTRU#1 and RX WTRU#1 to RX WTRU#2) for U2U relay.

[0145] Based on the SRAP sublayer configuration of SL logical channels, the source WTRU (e.g., the TX WTRU) may be configured with one or more SL logical channels and/or associated with SL transmission(s) for multiple receivers (e.g., RX WTRU#1 and/or RX WTRU#2). Given that the source WTRU may connect to the multi-hops with multiple RX WTRUs (e.g., RX WTRU#1, RX WTRU#2,.„ RX WTRU#N), the source WTRU may be configured with one or more SL logical channels and/or associated with SL transmission(s) for multiple receivers (e.g., RX WTRU#1, RX WTRU#2,.., RX WTRU#N).

[0146] The source WTRU may receive the configuration(s) of SL logical channel(s), for example, via a cell specific RRC message or a dedicated RRC message, or (pre)configured (e.g., be preconfigured with the configuration(s) of SL logical channel(s)). The source WTRU may receive a list of configurations of one or more SL logical channels associated with an SL transmission as one or more of the followings: one or more SL logical channels and associated the SL transmission from a source WTRU to RX WTRU#1; one or more SL logical channels and associated the SL transmission from the source WTRU to RX WTRU#2 via the RX WTRU#1;...; one or more SL logical channels and associated the SL transmission from the source WTRU to RX WTRU#N via from the RX WTRU#1 to RX WTRU#N-1 .

[0147] Latency may occur in relaying. In U2U relay, a TX WTRU (e.g., a source WTRU) may set up a PC5-RRC connection with a RX WTRU#1 (e.g., a relay WTRU) and/or may set up a PC5-RRC connection with a RX WTRU#2 (e.g., a target WTRU) via the RX WTRU#1 .

[0148] In U2U relay, an additional latency from a TX WTRU (e.g., a source WTRU) to the RX WTRU#2 may be considered between the TX WTRU (e.g., a source WTRU) and the RX WTRU#2 via the RX WTRU#1. For example, when the TX WTRU transmits an SL data to the RX WTRU#1 (e.g., a relay WTRU), the RX WTRU#1 may, for example, upon receiving the transmitted SL data, forward the received SL data to the RX WTRU#2 (e.g., a target WTRU). A value (e.g., msec) of latency in relaying from the TX WTRU to the RX WTRU#2 via the RX WTRU#1 may include one or more following: a forwarding delay from RX WTRU#1 to RX WTRU#2; and/or a propagation delay (e.g., a TX WTRU (e.g., a source WTRU) -> the RX WTRU#1-> the RX WTRU#2); and/or a retransmission delay (e.g., a TX WTRU (e.g., source WTRU) -> the RX WTRU#1; and/or the RX WTRU#1-> the RX WTRU#2) based on NACK (e.g., MAC, RLC); and/or a decoding and/or processing delay in the RX WTRU#1 and/or the RX WTRU#2 (e.g., receiving 1^st stage SCI and 2^nd stage SCI and PSSCH).

[0149] The latency in relaying may be configured to the TX WTRU (e.g., the source WTRU). [0150] In examples, the TX WTRU may receive a value of latency (e.g., maximum and/or minimum) in relaying from the RX WTRU#1. The RX WTRU#1 may determine the latency in relaying (e.g., based on the RX WTRU#Ts capability, sidelink discovery reference signal received power (SD-RSRP), a distance (e.g., between the RX WTRU#1 and the RX WTRU#2)). Based on the received value of latency, the TX WTRU may determine an E2E latency in relaying.

[0151] In examples, the TX WTRU may receive a value of latency (e.g., maximum and/or minimum) in relaying from one or more RX WTRUs (e.g., a RX WTRU#N). The RX WTRU#N may determine the latency in relaying (e.g., based on the RX WTRU#N’s capability, SD-RSRP, a distance (e.g., between the RX WTRU#N and a RX WTRU#N+1)). Based on the received value of latency, the TX WTRU may determine an E2E latency in relaying.

[0152] In examples, the TX WTRU may be configured with a value of latency in relaying as a time (e.g., maximum and/or minimum) in relaying from the network. The latency value may be associated with one or more relay WTRU operations. For example, the network may configure the value of the latency in relaying via a cell-specific message, or dedicated RRC message.

[0153] In examples, the TX WTRU may be configured with a latency in relaying as an offset value (e.g., maximum and/or minimum). The latency offset value may be associated with one or more relay WTRUs. The TX WTRU may be configured with the offset value (e.g., to the TX WTRU). For example, the network may configure the value of offset, for example, via a cell-specific message, or dedicated RRC message, or the TX WTRU (e.g., a source WTRU) may be (pre-)configured.

[0154] A value (e.g., msec) of latency in relaying (e.g., in examples extended to N RX WTRUs) may include one or more of the following: a forwarding delay from RX WTRU#1 to RX WTRU#N; and/or a propagation delay (e.g., a TX WTRU (e.g., a source WTRU) -> the RX WTRU#1-> the RX WTRU#2->the RX WTRU#N); and/or a retransmission delay (e.g., a TX WTRU (e.g., a source WTRU) -> the RX WTRU#1; and/or the RX WTRU#1-> the RX WTRU#2; and/or the RX WTRU#N-1 -> the RX WTRU#N) based on NACK (e.g., MAC, RLC); and/or a decoding and/or processing delay in the RX WTRU#1, the RX WTRU#2, and/or the RX WTRU#N (e.g., receiving 1^st stage SCI and 2^nd stage SCI and PSSCH).

[0155] In one or more examples herein, “Network” may include gNB or NG-RAN. “SL LC” and “Sidelink logical channel” may be used interchangeably in one or more examples herein. “A priority” and “SL priority” may be used interchangeably in one or more examples herein.

[0156] Resource (re-)selection for U2U relay may be performed. For example, a TX WTRU (e.g., a source WTRU) may determine an SL resource for U2U relay and/or determine to trigger an SL resource (re-)selection, for example, based on active time(s) of RX WTRU#1 and RX WTRU#2. [0157] Resource selection may be performed. A TX WTRU (e.g., a source WTRU) may establish PC5 connections with RX WTRU#1 (e.g., a relay WTRU) and RX WTRU#2 (e.g., a target WTRU) via the RX WTRU#1. The TX WTRU may be configured with one or more SL logical channels associated with SL transmission(s) to the RX WTRU#2 via the RX WTRU#1 . The TX WTRU may be configured with one priority threshold (e.g., reselection) for one or more (e.g., each) of the SL logical channels associated with SL transmission(s) to the RX WTRU#2 via the RX WTRU#1 .The TX WTRU may receive preferred active time(s) from the RX WTRU#1 and the RX WTRU#2.The TX WTRU may configure SL DRX configuration(s) (e.g., active time(s)) for the RX WTRU#1 and the RX WTRU#2. The TX WTRU may receive a latency in relaying (e.g., forwarding) from the RX WTRU#1. The TX WTRU may determine an effective active time for the RX WTRU#2 as the active time of the RX WTRU#2 offset in time by the latency of relaying.

[0158] If triggering (e.g., upon triggering) SL resource selection(s), the TX WTRU may determine one or more SL resources in the active time of the RX WTRU#1 and an effective active time of the RX WTRU#2, for example, if an SL data for transmission is associated with the one or more SL logical channels associated with SL transmission(s) to the RX WTRU#2 via the RX WTRU#1 .

[0159] Resource (re-)selection checking may be performed. In examples, if SL resource (re-)selection is triggered by an SL data and the SL data from the configured one or more SL logical channels associated with SL transmission(s) to the RX WTRU#2 via the RX WTRU#1 , the TX WTRU may determine whether or not to trigger the SL resource reselection as one or more of the following: if the (re-)selected resource is in the active time of the RX WTRU#1 and an effective active time of the RX WTRU#2, the TX WTRU may keep the current SL resource; if the (re-)selected resource is outside of the active time of the RX WTRU#1, the TX WTRU may trigger the resource (re-)selection; if the (re-)selected resource is in the active time of the RX WTRU#1 and outside of the effective active time of the RX WTRU#2, the TX WTRU may trigger the resource (re-)selection if the priority value of the SL data is lower than the configured threshold value and the remaining PDB is within the effective active time of the RX WTRU #2, and, otherwise, the TX WTRU may keep the current SL resource.

[0160] Configurations of one or more examples herein may be used. The TX WTRU may be configured with (e.g., by receiving configuration information) one or more SL logical channels according to one or more examples (e.g., examples on configuration of SL logical channel) herein. The TX WTRU may be configured with (e.g., by receiving configuration information) a latency in relaying according to one or more examples (e.g., examples on latency in relaying) herein.

[0161] Resource selection considering active time may be associated with certain logical channels (e.g., tied to specific logical channels). For example, an SL resource may be selected for an SL transmission of data associated with an SL logical channel based on active time(s) associated with one or more RX WTRUs if the SL logical channel is associated with a relay RX WTRU.

[0162] When an SL resource selection is triggered (e.g., by an arrival of SL data), a TX WTRU (e.g., MAC layer) may request from the PHY layer (e.g., of the TX WTRU) a subset of SL resources for an PSCCH and/or PSSCH transmission. For example, a determination may be made that SL data is available (e.g., for an SL transmission), and an SL resource selection may be performed based on the determination that the SL data is available. The WTRU (e.g., physical layer (PHY)) may receive, e.g., from MAC layer of the WTRU, the SL DRX active time regarding the destination. For example, an SL DRX configuration associated with a target RX WTRU may be received, and/or the SL DRX configuration may indicate the SL DRX active time.

[0163] The TX WTRU may consider an active time of a RX WTRU while determining a set (e.g., a subset) of SL resources for the TX WTRU (e.g., if SL DRX is configured to the RX WTRU). For example, the TX WTRU may determine an SL resource based on an active time of a RX WTRU. In some examples, if the TX WTRU may select one or more SL resources, for example, for SL transmission(s) outside an active time of the RX WTRU, the RX WTRU may not receive SL data transmitted via the SL transmission(s) (e.g., because the RX WTRU may skip monitoring (e.g., a PSCCH/PSSCH transmission) for the transmitted SL data during a time outside the active time). In examples, time outside the active time may include time before the start of the active time and the time after the end of the active time. In examples, a TX WTRU (e.g., a source WTRU) may consider the active time(s) of multiple WTRUs in a resource selection (e.g., 2 or more WTRUs) when data is available for certain logical channels. Certain SL logical channels (e.g., specific SL logical channels) may be configured for transmission(s) via a U2U relay. When SL data is available for transmission(s) for these SL logical channels, the TX WTRU may determine (e.g., select) one or more SL resources for SL transmission(s) within the active time(s) (e.g., slots/subframes) of one or more (e.g., all) RX WTRUs. For example, if SL DRX configurations are configured for the RX WTRU(s) (e.g., the RX WTRUs for all destinations), the TX WTRU may determine the SL resources for the SL transmission(s) based on the active time(s) of the RX WTRU(s). For example, the TX WTRU may determine one or more SL resources for the SL transmission(s) based on (e.g., within) one or more active times (e.g., active time(s) associated with one or more SL logical channels according to configuration(s) from an SRAP layer as described in one or more examples herein) as one or more of the following: the TX WTRU may determine the one or more SL resources based on the active time of the RX WTRU#1 when the SL resource selection is triggered by SL data associated with the one or more SL logical channels associated with SL transmission(s) to the RX WTRU#1; and/or, the TX WTRU may determine the one or more SL resources based on the active time(s) of the RX WTRU#1 and RX WTRU#2, when the SL resource selection is triggered by SL data associated with the one or more SL logical channels associated with SL transmission(s) to the RX WTRU#2 via the RX WTRU#1 .

[0164] An effective SL active time may be used to determine an SL resource. In examples, the RX WTRU#2 may be associated with an effective SL active time. When an SL resource selection is triggered by SL data associated with (e.g. belonging to/from) the one or more SL logical channels associated with SL transmission(s) to the RX WTRU#2 via the RX WTRU#1 (e.g., one or more SL logical channels configured for SL transmission(s) to be relayed through the RX WTRU#1 to the RX WTRU#2) , the TX WTRU may determine the one or more SL resources based on an effective active time (e.g., an effective active time associated with the RX WTRU#1 and the RX WTRU#2). For example, the effective active time may be determined based on an active time associated with the RX WTRU #1, an active time associated with the RX WTRU #2, and a relaying latency. When the SL data is transmitted from the TX WTRU to the RX WTRU#2 via the RX WTRU#1 (e.g., as a relay WTRU), a latency in relaying may be considered in the determination of the effective active time (e.g., as the effective active time of the RX WTRU#2).

[0165] In some examples, the latency (e.g., due to the relaying from the RX WTRU#1) may have an impact on the active time of the RX WTRU#2. For example, if an SL resource may be determined from the end of the active time of the RX WTRU#1 (e.g., the end of both active time(s) of RX WTRU#1 and RX WTRU#2), the active time of the RX WTRU #2 may end before data relayed though the RX WTRU #1 to the RX WTRU #2 is received by the RX WTRU #2 (e.g., the active time of the RX WTRU #2 may end, and the RX WTRU#2 may not receive the data due to the latency in relaying). For example, an effective active time (e.g., an effective active time of the RX WTRU#2) may be determined as an active time with a consideration of a latency in relaying from the RX WTRU#1 to the RX WTRU#2. For example, an effective active may be determined based on at least overlapped time of the active time of the RX WTRU#1 and RX WTRU#2 and a relaying latency (e.g., excluding the latency of relaying from the end of the active time of the RX WTRU#2 within the overlapped time). In examples, the first active time may be a first time period associated with a first starting time and a first ending time, and the second active time may be a second time period associated with a second starting time and a second ending time. The WTRU may determine an overlapping time period of the first time period and the second time period. The WTRU may determine an effective active time based on the overlapping time period and the relaying latency associated with the first RX WTRU. For example, the overlapping time period may start at a later one of the starting time of the first time period and the starting time of the second time period. The overlapping time period may end at an earlier one of the ending time of the first time period and the ending time of the second time period. In some examples, the effective active time (e.g., the effective active time of the RX WTRU#2) may be the overlapping time period (e.g., equal to the overlapping time period) or may be a time period that is shorter (e.g., as shown in FIG. 9) than the overlapping time period of the RX WTRU#1 and RX WTRU#2.

[0166] For example, the TX WTRU may determine the effective active time (e.g., the effective active time of the RX WTRU#2) using one or more of the following. In examples (e.g., case #1), when the active time (e.g., on duration) of the RX WTRU#1 and the active time of RX WTRU#2 end at the same time, the TX WTRU may select the overlapping time period associated with the active time of the RX WTRU#1 and the active of the RX WTRU#2 and/or then exclude the latency of relaying from the end of the active time of the RX WTRU#2. FIG. 8 illustrates an example of an effective active time of the RX WTRU#2 (case #1). As shown in FIG. 8, the overlapping period ends at time 804, and the effective active time ends at time 802. The difference between the time 802 and the time 804 is the latency of relaying.

[0167] In examples (e.g., case #2)), when the active time (e.g., on duration) of the RX WTRU#1 ends later than the active time of the RX WTRU#2, the TX WTRU may select the overlapping time period associated with the active time of the RX WTRU#1 and the active time of the RX WTRU#2 and/or then exclude the latency of relaying from the end of the active time of the RX WTRU#2. FIG. 9 illustrates an example of an effective active time of the RX WTRU#2 (case #2). As shown in FIG. 9, the overlapping time period ends at time 904, and the effective active time ends at time 902. The difference between the time 902 and the time 904 is the latency of relaying.

[0168] In examples (e.g., case #3)), when the active time (e.g., on duration) of the RX WTRU#1 ends earlier than the active time of the RX WTRU#2 ends, the TX WTRU may select the overlapping time period associated with the active time of the RX WTRU#1 and the active time of the RX WTRU#2. FIG. 10 illustrates an example of an effective active time of the RX WTRU#2 (case #3). As shown in FIG. 10, the overlapping period ends at time 1004, the same time as the effective active time ends.

[0169] Resource (re-)selection may be performed. In examples, a TX WTRU (e.g., a source WTRU) may be (pre-)configured a threshold value for a priority to determine SL resource reselection. Based on a priority value of an SL logical channel being lower than the threshold value, the TX WTRU may perform the resource (re-)selection. The network may configure the threshold value for a priority, for example via a cellspecific message, or a dedicated RRC message to the TX WTRU, or the TX WTRU may be (pre- Jconfigured.

[0170] In some examples, a TX WTRU (e.g., a source WTRU) may determine one or more SL resources (e.g., by performing a resource reselection) for SL transmission(s) when a condition for a resource reselection is satisfied (e.g., when an SL resource selection is triggered as the result of the TX resource (re-)selection checking conditions). The TX WTRU may not trigger an SL resource reselection if a condition for a resource reselection is not satisfied. If an SL resource (re-)selection is triggered by an SL data associated with the one or more SL logical channels associated with the SL transmission(s) to the RX WTRU#2 via the RX WTRU#1 , the TX WTRU may trigger the SL resource (re-)selection or may not trigger the SL resource (re-)selection, according to one or more examples as described herein.

[0171] The TX WTRU may determine to perform an SL resource (re-)selection for one or more of the following cases: if the (re-)selected SL resource is outside the active time of the RX WTRU#1 (e.g., the RX WTRU#1 being the destination for the TX WTRU); or if the (re-)selected resource is within the active time of the RX WTRU#1 and outside the effective active time of the RX WTRU#2 (e.g., if the priority value of the SL data is lower than the (pre-)configured threshold value (e.g., the priority value is smaller (indicating higher priority) than the configured threshold value) and/or if the remaining PDB is smaller than the effective active time of the RX WTRU#2). In examples, the TX WTRU may determine that a first SL resource that has been selected is outside the effective active time of the RX WTRU#2 (and with the active time of the RX WTRU#1). The TX WTRU may determine that the priority value of the SL logical channel is lower than the configured threshold value. The TX WTRU may determine that the remaining PDB is within the effective active time of the RX WTRU#2. The TX WTRU may select a second SL resource for transmitting the data associated with an SL logical channel (e.g., by performing an SL resource reselection) based on the determination that the first SL resource is outside the effective active time of the RX WTRU#2, the determination that the priority value of the SL logical channel is lower than the configured threshold value and the determination that the remaining PDB is within the effective active time of the RX WTRU#2.

[0172] The TX WTRU may determine to keep the currently selected SL resource(s) (e.g., without performing an SL resource (re-)selection) in one or more of the following cases: if the (re-)selected resource is within the active time of RX WTRU#1 and the effective active time (e.g., the effective active time of RX WTRU#2); or if the (re-)selected resource is in the active time of the RX WTRU#1 and outside the effective active time of the RX WTRU#2 and if the priority value of the SL data is higher than the configured threshold value (e.g., the priority value is bigger (indicating lower priority) than the configured threshold value) and/or if the remaining PDB is smaller than the effective active time of the RX WTRU#2. [0173] Resource (re-)selection procedure may be extended to multi-hop U2U relays.

[0174] In examples, a TX WTRU (e.g., a source WTRU) may perform an SL resource selection for the number of RX WTRUs. For example, the TX WTRU may connect to multi-hops with multiple RX WTRUs (e.g., RX WTRU#1, RX WTRU#2,.„ RX WTRU#N). Given that the TX WTRU may connect to the multihops with multiple RX WTRUs (e.g., RX WTRU#1, RX WTRU#2,.„ RX WTRU#N), if the SL resource selection is triggered by an SL data belonging to/from the one or more SL logical channels associated with SL transmission(s) to the RX WTRU#N via from the RX WTRU#1 to RX WTRU#N-1 (e.g., configured from one or more examples herein, for example, examples on configuration of SL logical channel) then, the TX WTRU may determine the one or more SL resources based on active time(s) of the one or more (e.g., all) RX WTRUs (e.g., RX WTRU#1, RX WTRU#2,.„ RX WTRU#N). In this case, the TX WTRU may perform the following behaviors: in some examples, the TX WTRU (e.g., a source WTRU) may perform an SL resource selection until the TX WTRU may determine one or more SL resources with active time(s) (e.g., including effective active times) of one or more (e.g., all) WTRUs. When the TX WTRU may not determine one or more SL resources with actives (e.g., including effective active times) of the (e.g., all) RX WTRUs (e.g., from RX WTRU#2 to RX WTRU#N), the TX WTRU may report (e.g., one or more destinations of the RX WTRUs), for example, to the RRC layer. The TX WTRU may release (or reconfigure) one or more SL DRX configurations to the RX WTRUs which are associated with reported or reporting one or more destinations.

[0175] LCP enhancement(s) for U2U relay may be implemented. For example, a TX WTRU (e.g., a source WTRU) may select a destination associated with SL logical channel(s) during performing an LCP procedure based on the active time(s) of both RX WTRUs (e.g., RX WTRU#1, RX WTRU#2).

[0176] In examples, a TX WTRU (e.g., a source WTRU) may establish PC5 connections with RX WTRU#1 (e.g., a relay WTRU) and RX WTRU#2 (e.g., a target WTRU) via the RX WTRU#1. The TX WTRU may be configured with one or more SL logical channels associated with SL transmission(s) to the RX WTRU#2 via the RX WTRU#1 . The TX WTRU may be configured with a priority threshold for one or more (e.g., each) of the SL logical channels associated with SL transmission(s) to the RX WTRU#2 via the RX WTRU#1 . The TX WTRU may receive a latency in relaying (e.g., forwarding), for example, from the RX WTRU#1. The TX WTRU may receive preferred active time(s) from RX WTRU#1 and RX WTRU#2. The TX WTRU may configure SL DRX configuration(s) (e.g., active time(s)) for the RX WTRU#1 and the RX WTRU#2. For an SL grant (e.g., a selected SL grant), the TX WTRU may determine the SL destination(s) and/or SL logical channel(s) to include in the MAC PDU for the grant as one or more of the following: if data is available from one of the SL logical channels associated with transmission(s) to the RX WTRU#2 via the RX WTRU#1, and the selected SL grant is within the active time(s) of both the RX WTRU#1 and RX WTRU#2, and the priority value(s) of the one or more SL logical channel(s) is below the configured priority threshold value, the TX WTRU may select destination(s) associated with the RX WTRU#1, and first include data from SL logical channels associated with transmission(s) to the RX WTRU#2 before other SL logical channels; otherwise, the TX WTRU may select the destination(s) having the SL logical channel(s) with the highest priority and include an SL data from SL logical channels in the order of priority. The TX WTRU may transmit the SL data to the RX WTRU#1 using the selected grant. [0177] Configurations of one or more examples herein may be used. The TX WTRU may be configured with one or more SL logical channels according to one or more examples herein. The TX WTRU may be configured with a latency in relaying according to one or more examples herein.

[0178] Priority threshold(s) for SL logical channel(s) may be used.

[0179] In examples, a TX WTRU (e.g., a source WTRU) may be (pre-)configured a threshold value for an SL priority for one or more (e.g., each) SL logical channel (e.g., an SL logical channel associated with transmission(s) to RX WTRU#1 (or RX WTRU#2 via RX WTRU#1). For example, the network may configure the threshold value(s) for an SL priority to the TX WTRU via a cell-specific message, or dedicated RRC message to the TX WTRU, or the TX WTRU may be (pre-)configured. This configured priority value may be used (e.g. may be beneficial to be used) to prioritize SL logical channels associated with transmission(s) to the RX WTRU#2 (e.g., due to latency in relaying) while an SL data is available from one or more SL logical channels associated with transmission(s) to the RX WTRU#2 via a RX WTRU (e.g., the RX WTRU#1).

[0180] One or more LCP enhancement(s) may be implemented.

[0181] In examples, after one more SL grants are selected (e.g., on the SL), the TX WTRU may perform an LCP for the selected one or more SL grants. The TX WTRU may determine a destination associated with RX WTRU#1 and/or include firstly SL data from one or more SL logical channels (e.g., configuration from SRAP layer in one or more examples herein) associated with transmission to RX WTRU#2 when one or more (e.g., all) of the following conditions are satisfied: if an SL data is available from one or more SL logical channels associated with transmission(s) to the RX WTRU#2 via the RX WTRU#1; and if the selected SL grant is within the active time(s) of both the RX WTRU#1 and the RX WTRU#2 (e.g., an effective active time of the RX WTRU#2); and if a threshold value for an SL priority is (pre-)configured, and the SL priority value of the one or more SL logical channel is below the (pre-)configured threshold.

[0182] When one or more (e.g., all) of the above conditions are satisfied, the TX WTRU may prioritize one or more SL logical channels associated with transmission(s) to the RX WTRU#2, for example, for the selected SL grant. The TX WTRU may include firstly SL data from SL logical channels associated with transmission(s) to the RX WTRU#2 before including other SL logical channels, while including an SL MAC PDU (e.g., selecting SL logical channels) with the selected SL grant. When one or more (e.g., all) of the above conditions are satisfied, the TX WTRU may prioritize a selection of the RX WTRU#1 as the destination over other destinations which may have higher priority data available. If the one of the above conditions is not satisfied, the TX WTRU may determine to select having the SL logical channels with the highest SL priority and/or include data from SL logical channels in the order of SL priority (e.g., via the legacy SL LCP without enhancement). [0183] One or more LCP enhancement(s) may be extended to multi-hop U2U relays.

[0184] In examples, after one or more SL grants are selected, the TX WTRU may perform an LCP for the selected one or more SL grants. The TX WTRU may determine a destination associated with RX WTRU#1 and/or include firstly SL data from SL logical channels associated with transmission (s) from RX WTRU#2 to RX WTRU#N when one or more (e.g., all) of the following conditions are stratified: if data is available from one or more SL logical channels and associated with the SL transmission(s) from the TX WTRU to the RX WTRU#N via from the RX WTRU#1 to the RX WTRU#N; and if the selected SL grant is within the active time(s) of one or more (e.g., all) of the RX WTRUs (e.g., an effective active time of the RX WTRU#2); and if a threshold value for an SL priority is (pre-)configured, and the SL priority value of the SL data is below the threshold value (e.g., the (pre-)configured threshold value).

[0185] When one or more (e.g., all) of the conditions are satisfied for the one or more SL grants, the TX WTRU may prioritize SL logical channels associated with transmission(s) to the RX WTRU#2 while including the SL MAC PDU with the selected one or more SL grants. For example, the TX WTRU may include firstly SL data from the SL logical channels associated with transmission(s) to the RX WTRU#N (e.g., N=2/3/4/. . ,/N) sequentially (e.g., if available) before including other SL logical channels. If one of the above conditions is not satisfied, the TX WTRU may determine to select having the SL logical channels with the highest SL priority and/or include data from SL logical channels in the order of SL priority (e.g., via the legacy SL LCP without enhancement).

[0186] SL DRX configuration alignment may be based on PDB and/or latency in relaying. For example, a TX WTRU (e.g., a source WTRU) may determine an aligned SL DRX configuration (e.g., one duration, SL DRX cycle, etc.) for RX WTRUs. The aligned SL DRX configuration may be determined, for example, based on E2E PDB of the SL data and/or a latency in relaying.

[0187] In examples, a TX WTRU (e.g., a source WTRU) may establish PC5 connections with RX WTRU#1 (e.g., a relay WTRU) and RX WTRU#2 (e.g., a target WTRU) via the RX WTRU#1 . The TX WTRU may receive preferred active time(s) from the RX WTRU#1 and the RX WTRU#2, respectively. The TX WTRU may be configured with a CBR-dependent latency in relaying (e.g., a CBR-dependent maximum latency in relaying) by the network. The TX WTRU may determine a minimum PDB for E2E delivery, for example, from the QoS profiles mapped to one or more (e.g., each) SLRB. The TX WTRU may determine aligned SL DRX configuration(s) for one or more (e.g., each) of the RX WTRUs using one or more of the following conditions: the TX WTRU may select an SL DRX period and/or on duration such that the following is satisfied (e.g., SL DRX period - on duration) < (minimum PDB for E2E delivery - maximum latency in relaying). The TX WTRU may transmit the aligned SL DRX configuration(s) to one or more (e.g., each) of the RX WTRUs. [0188] In some examples, a TX WTRU (e.g., a source WTRU) may perform SL DRX alignment(s) for one or more (e.g., all) the RX WTRUs (e.g., RX WTRU#1, RX WTRU#2) in a centralized manner. When an SL data (e.g., periodic) is triggered, the TX WTRU may determine aligned SL DRX configuration(s) (e.g., a single aligned DRX configuration indicating on duration time, SL DRX cycle, etc.) for one or more (e.g., all) RX WTRUs.

[0189] Configurations of one or more examples herein may be used. The TX WTRU may be configured with one or more SL logical channels according to one or more examples herein. The TX WTRU may be configured with a latency in relaying according to one or more examples herein.

[0190] A CBR-dependent latency may be configured.

[0191] In examples, a TX WTRU (e.g., a source WTRU) may be configured with a CBR-dependent latency (e.g., a mapping of a set (e.g., one or more) of maximum latencies with relaying associated with each CBR value). This mapping may be appliable to a relaying operation (e.g., per hop). This mapping may be applicable to multi-hop relaying.

[0192] The TX WTRU may be configured, for example, with a CBR-dependent latency, for example, via a cell-specific message, or dedicated RRC message to the TX WTRU, or the TX WTRU may be (preconfigured, or the TX WTRU may derive or be derived from RX WTRU#1 based on exchanged capability signaling. Based on the (pre-)configured the CBR-dependent latency, the TX WTRU (e.g., a source WTRU) may determine, for example, the maximum latency in relaying associated with a measured CBR value. For this, the RX WTRU#1 may deliver the measured CBR value (e.g., between the RX WTRU#1 and RX WTRU#2 or from the RX WTRU#1 to the RX WTRU#2 ) to the TX WTRU. The TX WTRU may determine the maximum latency in relaying based on the CBR.

[0193] The TX WTRU may determine the latency (e.g., the relaying latency) using one or more of other factors. For example, the TX WTRU may be configured with a mapping between SL-RSRP and the latency. The TX WTRU may receive the latency from the relay WTRU (e.g., in a PC5-RRC message). The relay WTRU may determine a relaying latency based on the number of ingress/egress RLC channels (e.g., at the adaptation layer) and/or the QoS (e.g., PBR) configured for one or more (e.g., each) RLC channel.

[0194] Criteria of the aligned SL DRX configuration may be used.

[0195] In examples, the TX WTRU may determine the aligned SL DRX configuration when an SL data is triggered for an SL transmission. The TX WTRU may determine an SL DRX configuration (e.g., on duration, SL DRX cycle), for example, by taking into account the relaying latency. The TX WTRU may determine a PDB of the SL transmission based on an SL data of the configured one or more SL logical channels (e.g., configuration from an SRAP layer in one or more examples herein, for example, as described in the examples on configuration of SL logical channel). The TX WTRU may determine a minimum PDB for an E2E delivery (e.g., a source WTRU to a target WTRU) for the triggered SL data of the SL transmission as one or more of the following: the SL data of the PDB (e.g., msec) may be determined based on (e.g. may be known to the TX WTRU from) the QoS profile; the QoS profiles may be mapped to one or more (e.g., each) configured SL radio bearer (e.g., which SL radio bearer is associated with an SL logical channel), and, for example, the SL logical channel may be associated with the SL transmission from the source WTRU to the target WTRU (E2E).

[0196] To perform an SL DRX alignment, the TX WTRU may consider an SL DRX cycle and/oron duration based on, for example, the determined minimum PDB for an E2E delivery and/or the determined maximum latency of relaying. The TX WTRU may determine the maximum latency in relaying with a measured CBR value. The TX WTRU may determine the aligned SL DRX configuration (e.g., on duration) for one or more (e.g., each) RX WTRU. The TX WTRU may determine the SL DRX configuration (e.g., on duration, SL DRX cycle) for the SL transmission when the following condition is satisfied: (SL DRX period - on duration) < (minimum PDB for E2E delivery - maximum latency in relaying).

[0197] FIG. 11 illustrates example criteria of the aligned SL DRX configuration.

[0198] If receiving (e.g., upon receiving) the aligned SL DRX configuration, one or more (e.g., all) RX WTRUs may be configured with an (e.g., the same single) aligned SL DRX configuration.

[0199] A TX WTRU (e.g., a source WTRU) may further configure an offset in the DRX configuration for one or more (e.g., each) of the RX WTRUs. For example, the offset in the DRX configuration may represent the latency in relaying determined as described in one or more examples herein. The TX WTRU may use an increasing offset of one or more (e.g., each) of the RX WTRUs associated with multi-hop (e.g., an offset that increases based on a latency in relaying associated with an RX WTRU).

[0200] A WTRU may use fallback SL DRX configuration(s) (e.g., fall back to legacy SL DRX configuration(s)).

[0201] In examples, the TX WTRU may not configure (or be configured to) the aligned SL DRX configuration to RX WTRUs based on a certain condition, for example, if the following condition is satisfied: (SL DRX period - on duration) < (minimum PDB for E2E delivery - maximum latency in relaying with RX WTRU#1).

[0202] In some examples, the TX WTRU may not perform the SL DRX alignment based on the above condition. The TX WTRU may configure one or more SL DRX configurations per (e.g., each) RX WTRU (or per destination(s)) (e.g., RX WTRU#1, RX WTRU#2), for example, via a fallback SL DRX configuration (e.g., the legacy SL DRX configuration).

[0203] Aligned SL DRX configuration(s) may be extended to multi-hop U2U relays. [0204] In examples, a TX WTRU (e.g., a source WTRU) may perform an SL DRX alignment for the number of RX WTRUs. The TX WTRU may connect to the multi-hops with multiple RX WTRUs (e.g., RX WTRU#1, RX WTRU#2,.., RX WTRU#N). Given that the TX WTRU may connect to the multi-hops with multiple RX WTRUs (e.g., RX WTRU#1, RX WTRU#2,.„ RX WTRU#N), a latency in relaying from the TX WTRU to a target WTRU, in this case, may be accumulated and/or increased (e.g., due to the number of hops/RX WTRUs (e.g., a relay WTRU)), for example, latency relaying with RX WTRU#1 + latency relaying with RX WTRU#2 + latency relaying with RX WTRU3... + latency relaying with RX WTRU#N. The latency in relaying for multiple RX WTRUs may be configured according to one or more examples (e.g., examples on latency in relaying) herein (e.g., one or more offsets)

[0205] In some examples, the TX WTRU may not configure (or be configured to) the aligned SL DRX configuration to one or more (e.g., all) the RX WTRUs based on a certain condition, for example, if the following condition is satisfied: (SL DRX period - on duration) < (minimum PDB for E2E delivery - maximum latency in relaying with multiple RX WTRUs).

[0206] A WTRU may fall back to certain SL DRX configuration(s) (e.g., legacy SL DRX configuration(s)).

[0207] In examples, the TX WTRU may not perform the SL DRX alignment based on the above condition. The TX WTRU may not configure one or more SL DRX configurations per RX WTRU(s) (or per destination(s)) (e.g., RX WTRU#1, RX WTRU#2,.. „ RX WTRU#N). The TX WTRU may not configure a (e.g., any) SL DRX configuration to one or more (e.g., all) RX WTRUs.

[0208] Active time may be determined based on buffering time. For example, a RX WTRU (e.g., a relay WTRU) may determine an active time of the RX WTRU (e.g., a target WTRU) and different SL DRX configuration(s) (e.g., new SL DRX configuration(s) or updated/modified SL DRX configuration(s)), for example, based on a measured average buffering time change.

[0209] A WTRU (e.g., a relay WTRU) may establish PC5 connections with a TX WTRU (e.g., a source WTRU) and RX WTRU#2 (e.g., a target WTRU) via the RX WTRU#1 . The WTRU may receive an SL DRX configuration including a set of buffering times associated with one or more (e.g., each) active times (e.g., on duration). The WTRU may measure an averaged buffering time as the time between a reception of a PDU and the transmission of that PDU to the next hop. The WTRU may be configured with a threshold for an average buffering time change. If a measured average buffering time changes above the configured threshold, one or more of the followings may occur: the WTRU may select the active time (e.g., on duration) associated with the RX WTRU#2, for example, based on the measured buffering time and/or the received SL DRX configuration; the WTRU may send the different SL DRX configuration (e.g., the new SL DRX configuration or the updated/modified SL DRX configuration) to the RX WTRU #2; the WTRU may perform subsequent transmission(s) to the RX WTRU #2 based on the different active time (e.g., the new active time or the updated/modified active time). FIG. 12 illustrates an example for determining an SL DRX active time based on buffering time.

[0210] In examples, a RX WTRU#1 (e.g., a relay WTRU) may perform SL DRX alignment(s) for RX WTRU#2 (e.g., next hop) in the hop (e.g., between the RX WTRU#1 and the RX WTRU#2) in a distributed manner. The relay WTRU may determine an SL DRX configuration (e.g., a new active time) to send to an RX WTRU based on a received DRX configuration from a previous WTRU and/or its currently measured buffering time (e.g., change dynamically).

[0211] SL DRX configuration(s) may be based on buffering time.

[0212] In examples, a RX WTRU#1 (e.g., a relay WTRU) may receive, from a TX WTRU (e.g., a source WTRU), a SL DRX configuration for a RX WTRU#2 (e.g., during PC5-RRC connection setup with the TX WTRU and the RX WTRU#1). The SL DRX configuration may include a set of buffering times (e.g., an average measured buffering time) associated with one or more (e.g., each) active time for the RX WTRU#2 (e.g., the target WTRU). For example, a set of expected buffering times with the RX WTRU#1 (e.g., buffering time may include or be a time between a reception of a PDU and a transmission of the PDU to the next hop).

[0213] In some examples, the RX WTRU#1 may transmit the SL DRX configuration with buffering time and related threshold(s) for the RX WTRU#2 to align with the RX WTRU#Ts buffering time and/or the active time of the RX WTRU#2. For example, the RX WTRU#1 may request this alignment during an PC5- RRC connection setup. For example, the RX WTRU#1 may request when the SL transmission fails (e.g., due to the buffering time of the RX WTRU#1).

[0214] The RX WTRU#1 may be configured with a threshold value for an average buffering time change (e.g., msec) of one or more active times for the RX WTRU#2. For example, this threshold may indicate the allowable averaged buffering time change of one or more active times of the RX WTRU#2.

[0215] Another active time for the RX WTRU#2 may be selected.

[0216] In examples, when s measured average buffering time changes above the configured the threshold, the RX WTRU#1 may select another active time (e.g., on-duration, inactivity-timer, retransmission-timer, cycle, etc.) and/or send the different active time (e.g., the new active time or the updated/modified active time) to the RX WTRU#2 based on the SL DRX configuration associated with an (e.g., each) active time. In some examples, the RX WTRU#1 may select another active time based on a time gap between time stamps. For example, a gap may be derived between a time stamp of a reception of a PDU and a time stamp of the transmission of the PDU to the RX WTRU#2.

[0217] After selecting another active time for the RX WTRU#2, the RX WTRU#1 may send a different DRX configuration (e.g., a new DRX configuration or an updated/modified DRX configuration) (or delta signaling) to the RX WTRU#2. The RX WTRU#1 may transmit an indication (e.g., delta) via a signal or a message, for example, via an indication in the PHY signaling, or via a field in the MAC CE, or a message via the RRC message (e.g., PC5-RRC message). The RX WTRU#1 may select a longer active time (e.g., longer than the current active time) for the RX WTRU#2 when the measured average buffering time is larger than a threshold. Based on the updated/modified SL DRX configuration, the RX WTRU#2 may receive an SL data from the RX WTRU#1 during the active time.

[0218] In some examples, the RX WTRU#1 may receive, from the TX WTRU, a set of DRX configurations for the RX WTRU#2 with corresponding buffering time. The RX WTRU#1 may send (e.g., during an initial configuration, or based on (e.g., upon) a change in the measured buffering time) the DRX configuration (e.g., the specific DRX configuration) associated with the current measured buffering time to the RX WTRU #2. In some examples, RX WTRU#1 may receive a DRX configuration (e.g., a single DRX configuration), from the TX WTRU, for the RX WTRU#2. The RX WTRU#1 may be configured by the network with a rule for modifying the received configuration based on its currently measured buffering time. When the buffering time changes, the RX WTRU#1 may send a different DRX configuration (e.g., a new DRX configuration or a modified DRX configuration) to the RX WTRU#2 by applying the configured rule to the DRX configuration received from the TX WTRU.

[0219] Another active time may be selected for RX WTRU#N.

[0220] In examples, the RX WTRU#N-1 may receive an SL DRX configuration for the RX WTRU#N, and the SL DRX configuration may include a set of buffering times (e.g., an average measured buffering time) associated with an (e.g., each) active time for the RX WTRU#N (e.g., when the RX WTRU#N-1 may receive an SL DRX configuration for the RX WTRU#N, the SL DRX configuration may include a set of buffering times associated with each active time for the RX WTRU#N).

[0221] In some examples, when a measured average buffering time of the active time (e.g., on duration) changes above the configured threshold, the RX WTRU#N-1 may select another active time (e.g., on- duration, inactivity-timer, retransmission-timer, cycle, etc.) to/for the RX WTRU#N, for example, based on the SL DRX configuration associated with an (e.g., each) active time.

[0222] Path selection may be based on SL DRX for U2N relay. For example, a TX WTRU (e.g., a source WTRU) may determine a path (e.g., a direct path or an indirect path) based on the active time of a RX WTRU (e.g., a relay WTRU).

[0223] In examples, a TX WTRU (e.g., a source WTRU) may establish PC5 connections with RX WTRU#1 (e.g., a relay WTRU). The TX WTRU may configure an SL DRX configuration to the RX WTRU. The TX WTRU may be configured with a CBR threshold for path (re-)selection. If (e.g., upon triggering) data (e.g., a new data) in one or more SL logical channels associated with uplink transmission(s) via a split bearer over multipath (e.g., using Uu transmission or SL transmission) is triggered, the TX WTRU may determine an indirect path or a direct path for the uplink transmission(s) based on one or more of the following: the TX WTRU may determine the direct path, if the RX WTRU#1 is outside of the active time, and if the latency of the indirect transmission has not satisfied E2E QoS, and if the measured CBR value is above the configured CBR threshold; the TX WTRU may determine the indirect path, if the RX WTRU#1 is active time, and if the latency of the indirect transmission has satisfied E2E QoS, and if the measured CBR value is below the configured CBR threshold. The TX WTRU may transmit the data via the UL or SL based on the determined path.

[0224] U2N relay operation over multipath may be implemented.

[0225] In U2N relay operation, a TX WTRU (e.g., a source WTRU) may support a multi-path operation (e.g., either a direct path to the network or an indirect path to the network via a relay WTRU). For a SL transmission via an indirect path, the TX WTRU may establish a PC5-RRC connection with a relay WTRU. For an UL transmission via a direct path, the TX WTRU may receive one or more uplink configurations by a network (e.g., a direct path).

[0226] The TX WTRU may be configured with one or more UL and/or SL logical channels associated with the indirect and/or direct UL transmissions: one or more SL logical channels associated with SL transmission(s); and/or one or more UL logical channels associated with UL transmission(s); and/or one or more UL/SL logical channels associated with UL transmission(s) via the relay WTRU (e.g., uplink transmission(s) via a split bearer over multipath).

[0227] When SL data (e.g., a new SL data) is triggered in the one or more UL/SL logical channels associated with uplink transmission(s) via the relay WTRU (e.g., via a split bearer over multipath), the TX WTRU may determine a direct path or an indirect path for the triggered SL data of the SL transmission(s). [0228] CBR threshold may be used for path (re-)selection.

[0229] In examples, a TX WTRU (e.g., a source WTRU) may be configured with a CBR threshold value for path (re-)selection. The network may configure the CBR threshold value, for example, via a cell-specific message, or dedicated RRC message to the TX WTRU, or the TX WTRU may be (pre-)configured. Based on the (pre-)configured CBR threshold value, the TX WTRU may determine an indirect path or a direct path. For example, the TX WTRU may determine an indirect path when a measured CBR value is below a pre-configured CBR threshold value. For example, the TX WTRU may determine a direct path when the measured CBR value is above the configured CBR threshold value.

[0230] E2E latency may be considered for path (re-)selection.

[0231] In examples, the TX WTRU may determine a minimum PDB for an E2E delivery (e.g., a source WTRU to target WTRU) as one or more of the following: the PDB (e.g., msec) may be determined based on (e.g., may be known to the TX WTRU from) the QoS profile; the QoS profiles may be mapped to one or more (e.g., each) configured SL radio bearers; the SL radio bearer(s) may be associated with an SL logical channel (e.g., the SL logical channel may be associated with the SL transmission from the source WTRU to the target WTRU (E2E)).

[0232] Path (re-)selection may be based on one or more conditions.

[0233] In examples, when SL data (e.g., a new SL data) is triggered in the one or more UL/SL logical channels associated with uplink transmission(s) via a relay WTRU (e.g., via a split bearer over multipath), the TX WTRU may determine to (re-)select a direct path when one or more of the following conditions are satisfied for the triggered UL transmission: if the RX WTRU#1 is outside of the active time for the triggered transmission; and if the latency of the indirect transmission has not satisfied E2E QoS; and if the measured CBR value is above the configured CBR threshold.

[0234] In some examples, when SL data (e.g., a new SL data) is triggered in the one or more UL/SL logical channels associated with uplink transmission(s) via s relay WTRU (e.g., via a split bearer over multipath), the TX WTRU may determine to (re-)select an indirect path when one or more of the following conditions are satisfied for the triggered UL transmission: if the RX WTRU#1 is within the active time for the triggered transmission; and if the latency of the indirect transmission has satisfied the E2E QoS; and if the measured CBR value is below the configured CBR threshold.

[0235] If the TX WTRU may not determine a direct or an indirect path since the above conditions are not satisfied, the TX WTRU may perform one or more of the following: the TX WTRU may keep the current path (e.g., indirect or direct); or the TX WTRU may select the path based on the values of measured RSRP signals (e.g., from synchronization signal block (SSB)/ physical broadcast channel (PBCH) or SL- SS reference signal received power (SS-RSRP) from physical sidelink broadcast channel (PSBCH) or SL- channel state information reference signal (CSI-RS)), and, for example, the TX WTRU may determine the direct path if the value of the measured Uu RSRP is above the value of the measured SL-RSRP, and the TX WTRU may determine the indirect path if the value of the measured Uu RSRP is below the value of measured the SL-RSRP. FIG. 13 illustrates an example path (re-)selection based on an SL DRX of a relay WTRU. The UE in one or more examples (e.g., the examples shown in one or more figures herein) may be interchangeably referred to as a WTRU.

[0236] Although features and elements described above are described in particular combinations, each feature or element may be used alone without the other features and elements of the preferred embodiments, or in various combinations with or without other features and elements.

[0237] Although the implementations described herein may consider 3GPP specific protocols, it is understood that the implementations described herein are not restricted to this scenario and may be applicable to other wireless systems. For example, although the solutions described herein consider LTE, LTE-A, New Radio (NR) or 5G specific protocols, it is understood that the solutions described herein are not restricted to this scenario and are applicable to other wireless systems as well. For example, while the system has been described with reference to a 3GPP, 5G, and/or NR network layer, the envisioned embodiments extend beyond implementations using a particular network layer technology. Likewise, the potential implementations extend to some or all types of service layer architectures, systems, and embodiments. The techniques described herein may be applied independently and/or used in combination with other resource configuration techniques.

[0238] The processes described herein may be implemented in a computer program, software, and/or firmware incorporated in a computer-readable medium for execution by a computer and/or processor. Examples of computer-readable media include, but are not limited to, electronic signals (transmitted over wired and/or wireless connections) and/or computer-readable storage media. Examples of computer- readable storage media include, but are not limited to, a read-only memory (ROM), a random access memory (RAM), a register, cache memory, semiconductor memory devices, magnetic media such as, but not limited to, internal hard disks and removable disks, magneto-optical media, and/or optical media such as compact disc (CD)-ROM disks, and/or digital versatile disks (DVDs). A processor in association with software may be used to implement a radio frequency transceiver for use in a WTRU, terminal, base station, RNC, and/or any host computer.

[0239] It is understood that the entities performing the processes described herein may be logical entities that may be implemented in the form of software (e.g., computer-executable instructions) stored in a memory of, and executing on a processor of, a mobile device, network node or computer system. That is, the processes may be implemented in the form of software (e.g., computer-executable instructions) stored in a memory of a mobile device and/or network node, such as the node or computer system, which computer-executable instructions, when executed by a processor of the node, perform the processes discussed. It is also understood that any transmitting and receiving processes illustrated in figures may be performed by communication circuitry of the node under control of the processor of the node and the computer-executable instructions (e.g., software) that it executes.

[0240] The various techniques described herein may be implemented in connection with hardware or software or, where appropriate, with a combination of both. Thus, the implementations and apparatus of the subject matter described herein, or certain aspects or portions thereof, may take the form of program code (e.g., instructions) embodied in tangible media including any other machine-readable storage medium wherein, when the program code is loaded into and executed by a machine, such as a computer, the machine becomes an apparatus for practicing the subject matter described herein. In the case where program code is stored on media, it may be the case that the program code in question is stored on one or more media that collectively perform the actions in question, which is to say that the one or more media taken together contain code to perform the actions, but that - in the case where there is more than one single medium - there is no requirement that any particular part of the code be stored on any particular medium. In the case of program code execution on programmable devices, the computing device generally includes a processor, a storage medium readable by the processor (including volatile and non-volatile memory and/or storage elements), at least one input device, and at least one output device. One or more programs that may implement or utilize the processes described in connection with the subject matter described herein, e.g., through the use of an API, reusable controls, or the like. Such programs are preferably implemented in a high level procedural or object-oriented programming language to communicate with a computer system. However, the program(s) can be implemented in assembly or machine language, if desired. In any case, the language may be a compiled or interpreted language and combined with hardware implementations.

[0241] Although example embodiments may refer to utilizing aspects of the subject matter described herein in the context of one or more stand-alone computing systems, the subject matter described herein is not so limited, but rather may be implemented in connection with any computing environment, such as a network or distributed computing environment. Still further, aspects of the subject matter described herein may be implemented in or across a plurality of processing chips or devices, and storage may similarly be affected across a plurality of devices. Such devices might include personal computers, network servers, handheld devices, supercomputers, or computers integrated into other systems such as automobiles and airplanes.

[0242] In describing the preferred embodiments of the subject matter of the present disclosure, as illustrated in the Figures, specific terminology is employed for the sake of clarity. The claimed subject matter, however, is not intended to be limited to the specific terminology so selected, and it is to be understood that each specific element includes all technical equivalents that operate in a similar manner to accomplish a similar purpose.

Claims

CLAIMS What is Claimed:

1 . A wireless transmit/receive unit (WTRU), comprising: a processor configured to: determine that a sidelink (SL) logical channel is associated with an SL transmission to be relayed through a first RX WTRU to a second RX WTRU; determine a first SL discontinuous reception (DRX) configuration associated with the first RX WTRU and a second SL DRX configuration associated with the second RX WTRU, wherein the first SL DRX configuration indicates a first active time and the second SL DRX configuration indicates a second active time; based on a priority value of the SL logical channel being lower than a threshold value, determine an SL resource for the SL transmission based on the first active time, the second active time, a relaying latency associated with the first RX WTRU, and a packet delay budget (PDB) associated with the SL logical channel; and send the SL transmission on the SL resource.

2. The WTRU of claim 1 , wherein the first active time is a first time period associated with a first starting time and a first ending time, and the second active time is a second time period associated with a second starting time and a second ending time, and wherein the processor is further configured to: determine an overlapping time period of the first time period and the second time period; and determine an effective active time based on the overlapping time period and the relaying latency associated with the first RX WTRU, wherein the SL resource is determined to be within the effective active time.

3. The WTRU of claim 2, wherein the overlapping time period starts at a later one of the starting time of the first time period and the starting time of the second time period and ends at an earlier one of the ending time of the first time period and the ending time of the second time period.

4. The WTRU of claim 2, wherein the PDB does not exceed the effective active time.

5. The WTRU of claim 2, wherein the SL resource is determined via a resource reselection, and the processor is further configured to perform the resource reselection based on a determination that a selected SL resource is outside the effective active time.

6. The WTRU of claim 1 , wherein the processor is further configured to determine that data associated with one or more SL logical channels is to be included in the SL transmission relayed through the first RX WTRU to the second RX WTRU, wherein the determination of the SL resource is triggered by the determination that the data associated with the one or more SL logical channels is to be included in the SL transmission.

7. The WTRU of claim 1 , wherein the SL resource is determined via a resource reselection, and the processor is further configured to perform the resource reselection based on a determination that a selected SL resource is outside the first active time.

8. The WTRU of claim 1 , wherein the processor is further configured to: establish a PC5 connection with the first RX WTRU; and send, to the first RX WTRU, a message indicating that a PC5 connection associated with the first RX WTRU and the second RX WTRU is to be established.

9. A method performed by a wireless transmit/receive unit (WTRU), comprising: determining that a sidelink (SL) logical channel is associated with an SL transmission to be relayed through a first RX WTRU to a second RX WTRU; determining a first SL discontinuous reception (DRX) configuration associated with the first RX WTRU and a second SL DRX configuration associated with the second RX WTRU, wherein the first SL DRX configuration indicates a first active time and the second SL DRX configuration indicates a second active time; based on a priority value of the SL logical channel being lower than a threshold value, determining an SL resource for the SL transmission based on the first active time, the second active time, a relaying latency associated with the first RX WTRU, and a packet delay budget (PDB) associated with the SL logical channel; and sending the SL transmission on the SL resource.

10. The method of claim 9, wherein the first active time is a first time period associated with a first starting time and a first ending time, and the second active time is a second time period associated with a second starting time and a second ending time, and wherein the method further comprises: determining an overlapping time period of the first time period and the second time period; and determining an effective active time based on the overlapping time period and the relaying latency associated with the first RX WTRU, wherein the SL resource is determined to be within the effective active time.

11 . The method of claim 10, wherein the overlapping time period starts at a later one of the starting time of the first time period and the starting time of the second time period and ends at an earlier one of the ending time of the first time period and the ending time of the second time period.

12. The method of claim 10, wherein the PDB does not exceed the effective active time.

13. The method of claim 10, wherein the SL resource is determined via a resource reselection, and the method further comprises performing the resource reselection based on a determination that a selected SL resource is outside the effective active time.

14. The method of claim 9, further comprising determining that data associated with one or more SL logical channels is to be included in the SL transmission relayed through the first RX WTRU to the second RX WTRU, wherein the determination of the SL resource is triggered by the determination that the data associated with the one or more SL logical channels is to be included in the SL transmission.

15. The method of claim 9, wherein the SL resource is determined via a resource reselection, and the method further comprises performing the resource reselection based on a determination that a selected SL resource is outside the first active time.