WO2025034322A1

WO2025034322A1 - Carrier selection among licensed and unlicensed carriers

Info

Publication number: WO2025034322A1
Application number: PCT/US2024/036562
Authority: WO
Inventors: Martino Freda; Tuong Hoang; Aata EL HAMSS; Tao Deng; Virgile Garcia
Original assignee: InterDigital Patent Holdings Inc
Current assignee: InterDigital Patent Holdings Inc
Priority date: 2023-08-07
Filing date: 2024-07-02
Publication date: 2025-02-13
Anticipated expiration: 2026-02-07

Abstract

Methods and devices are disclosed for a wireless transmit receive unit (WTRU) to select at least one unlicensed carrier(s) for sidelink (SL) multicarrier transmission. A method for the WTRU to transmit sidelink (SL) data on multiple carriers may include receiving configuration information including one or more thresholds of prioritized bit rate (PBR), buffer status or constant bit rate (CBR) to determine whether to allow transmission on an unlicensed carrier for a SL radio bearer (SLRB), selecting at least one licensed carrier and one unlicensed carrier for multi-carrier transmission of SL data based on the configurated threshold and transmitting data on each of the selected carriers to a peer WTRU. Additional embodiments are disclosed.

Description

CARRIER SELECTION AMONG LICENSED AND UNLICENSED CARRIERS

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63/531,211, filed August 7, 2023, the contents of which are incorporated herein by reference.

BACKGROUND

[0002] Multicarrier has been specified for new radio (NR) sidelink (SL) in 3^rd generation partnership (3GPP) Release 18. Multicarrier is expected to use long term evolution (LTE) as a baseline, while potentially considering some differences to account for unicast transmission in NR. In addition, unlicensed operation for SL is also being specified and there are no expectations to have these two features interact. Specifically, multicarrier operation is considered for licensed carriers in the case of Rel18 user equipment (UE). Furthermore, unlicensed operation is being considered for a single carrier only. It is expected, however, that future releases will need to support UEs which operate over a combination of licensed and unlicensed carriers.

[0003] A number of areas specific to sidelink (SL) communication are being considered for operating licensed and unlicensed carriers in a multicarrier fashion, including carrier selection, discontinuous reception (DRX) and hybrid automatic repeat request (HARQ) radio link failure (RLF). Carrier selection based on priority and channel busy ratio (CBR) may not be appropriate when a mix of licensed and unlicensed carriers are present. Specifically, licensed and unlicensed carriers cannot be considered equal from the perspective of resource usage, maintenance of QoS, and access. DRX for SL is currently designed for single carrier only. Multicarrier DRX exists for uplink and downlink (i.e., Uu interface) based on DRX groups. However, defining DRX groups has the limitations, in the context of multicarrier licensed/unlicensed in SL, that a receive (RX) UE would need to monitor all carriers configured for transmission by a transmit (TX) UE, which may not be ideal from a power consumption perspective, particularly if some of these carriers are in an unlicensed band. Hybrid automatic repeat request (HARQ)-based RLF determination is also designed for single carrier only. In SL multicarrier, whether issues on one carrier warrant determination of SL RLF of the entire link or not may vary on the carriers themselves and/or potentially on whether they are licensed/unlicensed.

[0004] Carrier selection in LTE/NR for licensed carriers treats all carriers equally and considers CBR only. Unlicensed carriers, however, are clearly not applicable for certain types of traffic and only CBR-based approach to selecting carriers may result in selecting a set of carriers that may not meet QoS requirements. SUMMARY

[0005] According to certain aspects of the disclosure, one or more of the foregoing issues may be addressed by a UE, interchangeably referred to herein as a wireless transmit receive unit (WTRU), that selects at least one unlicensed carrier(s) for multicarrier transmission based on the QoS of data and/or amount of data available and/or the CBR on the licensed carriers.

[0006] In one example, a SL TX WTRU may be configured with one or more thresholds to determine whether to allow transmission on an unlicensed carrier for a SL radio bearer (SLRB), e.g., prioritized bit rate, buffer status threshold, CBR threshold, etc.. For each destination L2 ID configured for transmission on both licensed and unlicensed, a method may include: (I) establishing one or more SL radio bearers for transmission to the L2 IDs based on the established QoS flows; (ii) determining whether to select at least one unlicensed carrier based on the one or more configured parameters in the SL radio bearers and/or the buffer status associated with the one or more SL radio bearers allowed for unlicensed operation and/or the largest CBR on any of the selected licensed carriers; (iii) selecting, for the destination, a number of licensed carriers and a number of unlicensed carriers; and (iv) transmitting data for the L2 destination ID on each of the selected carriers.

[0007] In some aspects, determining whether to select at least one unlicensed carrier based on the one or more configured parameters in the SL radio bearers and/or the buffer status associated with the one or more SL radio bearers allowed for unlicensed operation and/or the largest CBR on any of the selected licensed carriers may include, for example, if a SL radio bearer (SLRB) is configured with a prioritized bit rate greater than the threshold, if the buffer status associated with one or more SLRBs is greater than the threshold for a configured period of time, and/or if the minimum CBR of any selected licensed carrier is greater than a CBR threshold. Additional embodiments are disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] A more detailed understanding may be had from the following description, given by way of example in conjunction with the accompanying drawings, wherein like reference numerals in the figures indicate like elements, and wherein:

[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. 1B is a system diagram illustrating an example wireless transmit/receive unit (WTRU) that may be used within the communications system illustrated in FIG. 1 A according to an embodiment; [0011] FIG. 1C 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. 1A according to an embodiment;

[0012] FIG. 1D 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. 1 A according to an embodiment; and

[0013] FIG. 2 is a flow diagram illustrating a method of carrier selection among licensed and unlicensed carriers according to an embodiment.

DETAILED DESCRIPTION

[0014] 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 discrete Fourier transform Spread OFDM (ZT-UW-DFT-S-OFDM), unique word OFDM (UW-OFDM), resource block-filtered OFDM, filter bank multicarrier (FBMC), and the like.

[0015] As shown in FIG. 1A, the communications system 100 may include wireless transmit/receive units (WTRUs) 102a, 102b, 102c, 102d, a radio access network (RAN) 104, a core network (ON) 106, 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 (STA), 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-Fl 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.

[0016] 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, 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 NodeB, an eNode B (eNB), a Home Node B, a Home eNode B, a next generation NodeB, such as a gNode B (gNB), a new radio (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.

[0017] The base station 114a may be part of the RAN 104, 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, and the like. 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.

[0018] 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).

[0019] 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 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 116 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 Uplink (UL) Packet Access (HSUPA).

[0020] 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).

[0021 ] 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 NR.

[0022] 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).

[0023] 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, CDMA20001 X, 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.

[0024] 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. 1A, 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 ON 106.

[0025] The RAN 104 may be in communication with the GN 106, 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 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 and/or the CN 106 may be in direct or indirect communication with other RANs that employ the same RAT as the RAN 104 or a different RAT. For example, in addition to being connected to the RAN 104, which may be utilizing a NR radio technology, the CN 106 may also be in communication with another RAN (not shown) employing a GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology. [0026] TheCN 106 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 or a different RAT.

[0027] 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. 1 A 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.

[0028] FIG. 1B is a system diagram illustrating an example WTRU 102. As shown in FIG. 1B, 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 subcombination of the foregoing elements while remaining consistent with an embodiment.

[0029] 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), 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.

[0030] 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.

[0031] Although the transmit/receive element 122 is depicted in FIG. 1B 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.

[0032] 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.

[0033] 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 unitor 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).

[0034] 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.

[0035] 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 location-determination method while remaining consistent with an embodiment.

[0036] 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, a humidity sensor and the like.

[0037] 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 DL (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 selfinterference 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 WTRU 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 DL (e.g., for reception)).

[0038] FIG. 10 is a system diagram illustrating the RAN 104 and the ON 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 ON 106.

[0039] 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.

[0040] 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. 1C, the eNode-Bs 160a, 160b, 160c may communicate with one another over an X2 interface.

[0041] The CN 106 shown in FIG. 1C may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (PGW) 166. While the foregoing elements are 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.

[0042] The MME 162 may be connected to each of the eNode-Bs 162a, 162b, 162c 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.

[0043] 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. [0044] 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.

[0045] The CN 106 may facilitate communications with other networks. For example, the ON 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 landline 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.

[0046] Although the WTRU is described in FIGS. 1A-1D 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.

[0047] In representative embodiments, the other network 112 may be a WLAN.

[0048] 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 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 802.11z tunneled DLS (TDLS). A WLAN using an Independent BSS (IBSS) 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.

[0049] When using the 802.11ac 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. 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 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.

[0050] 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.

[0051] Very High Throughput (VHT) STAs may support 20M Hz, 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).

[0052] Sub 1 GHz modes of operation are supported by 802.11 af and 802.11 ah. The channel operating bandwidths, and carriers, are reduced in 802.11af and 802.11 ah relative to those used in 802.11n, and 802.11 ac. 802.11af 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, 802.11ah may support Meter Type Control/Machine-Type Communications (MTC), such as MTC devices in a macro coverage area. MT C 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).

[0053] WLAN systems, which may support multiple channels, and channel bandwidths, such as 802.11n, 802.11ac, 802.11af, and 802.11ah, 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, all available frequency bands may be considered busy even though a majority of the available frequency bands remains idle.

[0054] 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.

[0055] FIG. 1D 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 NR radio technology to communicate with theWTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0056] The RAN 104 may include gNBs 180a, 180b, 180c, though it will be appreciated that the RAN 104 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).

[0057] 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 a varying number of OFDM symbols and/or lasting varying lengths of absolute time).

[0058] 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.

[0059] 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, DC, 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. 1D, the gNBs 180a, 180b, 180c may communicate with one another over an Xn interface.

[0060] The CN 106 shown in FIG. 1D 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 the foregoing elements are 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.

[0061] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 104 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 protocol data unit (PDU) sessions with different requirements), selecting a particular SMF 183a, 183b, management of the registration area, termination of non- access stratum (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 MTC access, and the like. The AMF 182a, 182b may provide a control plane function for switching between the RAN 104 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.

[0062] The SMF 183a, 183b may be connected to an AMF 182a, 182b in the CN 106 via an N11 interface. The SMF 183a, 183b may also be connected to a UPF 184a, 184b in the CN 106 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 DL data notifications, and the like. A PDU session type may be IP-based, non-IP based, Ethernet-based, and the like.

[0063] The UPF 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 104 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 DL packets, providing mobility anchoring, and the like.

[0064] The CN 106 may facilitate communications with other networks. 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. In one embodiment, the WTRUs 102a, 102b, 102c may be connected to a local 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.

[0065] In view of FIGs. 1A-1D, and the corresponding description of FIGs. 1A-1D, 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.

[0066] 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 performing testing using over-the-air wireless communications.

[0067] 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.

[0068] Solutions herein are disclosed for multicarrier operation by a SL WTRU where carriers can be licensed (i.e., access is via legacy SL) or unlicensed (i.e., access requires LBT-like operation). However, solutions can be extended to consider carriers having different properties apart from the access mechanism. In many cases, solutions can similarly be applied to multicarrier over multiple licensed carriers, where there may be some difference in the configuration or properties of such carriers. Finally, solutions are applicable also to operation over multiple bandwidth parts, multiple RB sets, etc., instead of consideration of multiple carriers.

[0069] Embodiments for carrier selection among licensed and unlicensed carriers are now described. As mentioned previously, carrier selection in LTE/NR for licensed carriers treats all carriers equally and considers channel busy ratio (CBR) only. Unlicensed carriers, however, are clearly not applicable for certain types of traffic and only CBR-based approach to selecting carriers may result in selecting a set of carriers that may not meet QoS requirements. [0070] In one example embodiment, a WTRU selects at least one unlicensed carrier(s) for multicarrier transmission based on the QoS of data and/or amount of data available and/or the CBR on the licensed carriers.

[0071] Referring to FIG. 2, an example method 200 for carrier selection among licensed and unlicensed carriers is shown. A SL TX WTRU may be configured 205 with one or more thresholds to determine whether to allow transmission on an unlicensed carrier for a SLRB (e.g prioritized bit rate (PBR), buffer status threshold, CBR threshold, etc.). For each destination L2 ID configured for transmission on both licensed and unlicensed carriers, the WTRU may establish 210 one or more SL radio bearers for transmission to the L2 IDs based on the established QoS flows. Next, the TX WTRU determines 215 whether to select at least one unlicensed carrier based on the one or more configured parameters in the SL radio bearers and/or the buffer status associated with the one or more SL radio bearers allowed for unlicensed operation and/or the largest CBR on any of the selected licensed carriers. Based on determination 215, the TX WTRU selects 220, for the destination, a number of licensed carriers and a number of unlicensed carriers. The TX WTRU may then transmit 225 data for the L2 destination ID on each of the selected carriers.

[0072] In determining 215 whether to select at least one unlicensed carrier based on the one or more configured parameters in the SL radio bearers and/or the buffer status associated with the one or more SL radio bearers allowed for unlicensed operation and/or the largest CBR on any of the selected licensed carriers, examples may include: if a SLRB is configured with prioritized bit rate is greater than the threshold; if the buffer status associated with one or more SL radio bearers is greater than the threshold for a configured period of time; and/or if the minimum CBR of any selected licensed carrier is greater than the CBR threshold.

[0073] Carrier (re)selection behavior may be similar to legacy LTE V2X. Specifically, a SL WTRU may perform any of the following: (i) for each HARQ process, trigger carrier ( re-election based on certain conditions related to resource (re-election; (ii) for each L2 destination ID, select a number of carriers on which to transmit from the carriers that are configured for each L2 destination ID; (ill) select resources independently on each carrier per HARQ process; (iv) for a given grant on a carrier, perform a logical channel prioritization (LCP) procedure taking in account the L2 destinations which are allowed on the carrier; and/or (v) transmit the medium access control (MAC) packet data unit (MPDU) on the carrier.

[0074] Carrier (re— election conditions considerations for licensed or unlicensed carriers. In one family of solutions, a WTRU may perform carrier (re)selection by considering licensed and unlicensed carriers differently. The WTRU actions related to carrier (re-election may include any one, or a combi nation , of determining: (i) the number of carriers to select; (ii) the number of carriers of a given type to select; (iii) whether to include a carrier of a given type in the selected carriers; (iv) when/whether to trigger carrier ( re-election; (v) whether to select carriers of one type before another type; and/or (vi) whether to prioritize a carrier of one type (e.g . , licensed) over a carrier of another type (e.g., unlicensed).

[0075] Considering the type (e.g., licensed vs. unlicensed) of carrier during carrier (re)selection may include any of the following when performing the above determinations: performing the determination differently (e.g., using different conditions herein) when the carrier(s) are licensed compared to unlicensed; considering the type (licensed or unlicensed) of the currently selected carriers when performing the determination (e.g., based on some conditions herein being met); and/or performing the determination, possibly with conditions herein, while using a different condition, or a different factor when checking the conditions to perform the determination.

[0076] Conditions for (re-electing licensed and/or unlicensed carriers. In the above embodiments, the conditions for (re-electing carriers may include any one, or a combination of conditions relating to bearer configuration, configuration of the resource pool, QoS, cast type of the transmission, modulation and coding rate (MCR), enabled/disabled HARQ feedback, listen-before- talk (LBT) failure, channel busy ratio (CBR), channel occupancy rate (CR) and/or received signal strength indicator (RSSI) as described further below.

[0077] Conditions of bearer configuration may include: whether a bearer or logical channel is configured explicitly for some behavior or not; how the WTRU receives its bearer configuration (e.g., pre-configuration, system information block (SIB), or dedicated radio resource control (RRC) signaling); whether the bearer is a network (Uu) bearer or a SL bearer; and/or whether the bearer is a default bearer or not.

[0078] Conditions for configuration of the resource pool may encompass any factor related to the PHY channels configured for that resource pool/carrier, such as whether a PHY channel (e.g., physical sidelink feedback channel (PSFCH)) is configured or the amount/density of PSFCH configured.

[0079] QoS considerations may relate to any condition associated with a parameter related to QoS, possibly of a specific bearer, such as priority, reliability, maximum bit rate (MBR) or guaranteed bit rate (GBR), and/or prioritized bit rate of a logical channel (LCH).

[0080] Cast type may include any condition associated with whether the WTRU is transmitting by way of un icast/ g rou pcast/broadcast, such that at least one sidelink radio bearer (SLRB) is established for a specific type of cast, the WTRU’s transmissions are of a specific cast, and/or the amount of data available for transmission for a specific cast is above a threshold.

[0081] Conditions related to modulation coding rate (MCR) may include any conditions associated with the value of the MCR (e.g., compared to a threshold), whether MCR is configured, or the difference in MCR between two transmissions/bearers, etc.

[0082] Conditions related to HARQ feedback enabled/disabled may include whether an LCH has HARQ feedback enabled/disabled, whether a transmission has HARQ feedback enabled/disabled, and/or whether a WTRU is configured with HARQ resources (e.g., PSFCH, physical uplink control channel (PUCCH), etc.).

[0083] Conditions related to LBT failure may include whether LBT failure has been declared, potentially over a period of time, potentially on a carrier or one or more resource block (RB) set(s) associated with a carrier, and/or the number of times, potentially consecutive, where LBT failure has occurred, potentially on a carrier or one or more RB set(s) associated with a carrier.

[0084] Conditions related to channel busy ratio (CBR) may include the CBR being above or below a threshold, the CBR increasing/decreasing by a threshold amount and/or the CBR of one carrier being above/below the CBR of another carrier, possibly by a configured amount.

[0085] Conditions related to channel occupancy rate (CR) may include the CR being above or below a threshold, the CR increasing/decreasing by a threshold amount, and/or the CR of one carrier being above/below the CR of another carrier, possibly by a configured amount

[0086] Conditions related to received signal strength indicator (RSSI) may include the RSSI being above or below a threshold, the RSSI increasing/decreasing by a threshold amount, and/or the RSSI of one carrier being above/below the CR of another carrier, possibly by a configured amount.

[0087] In certain embodiments, a WTRU determines whether to select at least one (or a configured number) of carriers of a type. In one solution, a WTRU may determine whether to select one (or a configured number, or a configured percentage of the total usable) of licensed/unlicensed carriers during carrier selection, based on one or more of the above-described conditions. For example, a SL WTRU may be configured with a threshold buffer status, possibly associated with one or more of its established sidelink radio bearers (SLRBs). During carrier selection, a WTRU may be allowed to select at least one (or at least N, where N can be preconfigured) unlicensed carriers if the buffer status at the time of carrier selection trigger, is above a threshold.

[0088] In one example, a WTRU may trigger carrier (re)selection if the buffer status is below a threshold, possibly for a specified period of time, and the WTRU last selected (or is currently using) at least one (at least N) unlicensed carriers. Similarly, a WTRU may trigger carrier (re)selection if the buffer status is above a threshold, possibly for a period of time, and the WTRU last selected (or is currently using) no unlicensed carriers or less than N unlicensed carriers.

[0089] In one example, a SL WTRU may be configured with a CBR/CR threshold associated with any of the available/selected licensed carrier(s). If the CBR/CR of one/a configured number/all of the avai lable/selected licensed carrier(s) is above a threshold, the WTRU may select at least one (at least N) unlicensed carriers. Similarly, the WTRU may consider the minimum/maximum CR/CBR of the licensed carriers. Similarly, the WTRU may consider the average CBR/CR of the licensed carriers. For example, a SL WTRU may be configured with a CBR/CR threshold associated with carrier reselection. Specifically, if the CBR/CR of one/a configured number/all of the selected licensed carrier(s) is above a threshold, potentially for a specified period of time, and the WTRU has not selected any unlicensed carriers, the WTRU may trigger reselection. Similarly, if the CBR/CR of one/a configured number/all of the selected licensed carrier(s) is below a threshold, e.g ., for a period of time, and the WTRU is currently using an unlicensed carrier, the WTRU may trigger carrier reselection.

[0090] In one example embodiment, a SL WTRU may be configured with an indication in the SLRB configuration of whether a specific bearer allows selection of one or more unlicensed carriers. If the WTRU has such a SLRB established, the WTRU may select at least one (at least N) unlicensed carriers. Alternatively, if the WTRU has data available for transmission on at least one such established SLRB, the WTRU may select at least one (at least N) unlicensed carriers. For example, a SL WTRU may be configured with an indication in the SLRB configuration of the type of carrier that is preferred. A WTRU may select at least one unlicensed/licensed carrier if all/a configured number/none of the SLRB configurations indicate that unlicensed/licensed is preferred.

[0091] In another example embodiment, a SL WTRU may be configured with a threshold guaranteed bit rate (GBR), a prioritized bit rate (PBR), maximum bit rate (MBR), or similar QoS parameter related to a data rate. If the WTRU has established SLRB(s) for which the (potentially total) configured value of the QoS profile is above a threshold, the WTRU may select at least one (at least N) unlicensed carriers.

[0092] As another example, a SL WTRU may be configured with an RSSI threshold, or alternatively, a similar threshold related to measuring the amount of WiFi activity in an unlicensed carrier. Such a threshold may be configured per SLRB. If the number of unlicensed carriers in which the measured RSSI is below a threshold is above a number of carrier threshold, the WTRU may select at least one (at least N) unlicensed carriers. [0093] In some embodiments, a SL WTRU may select a carrier type based on the cast type of its transmissions. For example, if the WTRU has broadcast transmissions, it may select only (or prioritize selection of) licensed carriers. A SL WTRU may select a number of unlicensed carriers and/or licensed carriers to take into account the number of PSFCH resources configured for the carriers (i.e., select a number of carriers or the carriers which have at least a threshold number of PSFCH resources).

[0094] Although features and elements are described above in particular combinations, one of ordinary skill in the art will appreciate that each feature or element can be used alone or in any combination with the other features and elements. In addition, the methods described herein may be implemented in a computer program, software, or firmware incorporated in a computer-readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted over wired or wireless connections) and 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 internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks, and digital versatile disks (DVDs). A processor in association with software may be used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer.

Claims

CLAIMS What is Claimed:

1. A method for a wireless transmit and receive unit (WTRU), the method comprising: receiving configuration information including one or more thresholds for prioritized bit rate (PBR), buffer status or channel busy ratio (CBR), to determine whether to allow transmission on an unlicensed carrier for a sidelink (SL) radio bearer (SLRB); for a destination layer 2 (L2) ID configured for transmission on both licensed and unlicensed carriers, establishing one or more SLRBs for transmission for the L2 ID based on established quality of service (QoS) flows; selecting at least one licensed carrier and at least one unlicensed carrier for multicarrier transmission of SL data for the L2 ID based on the configured one or more thresholds; and transmitting data on each of the selected carriers for the L2 ID to a peer WTRU.

2. The method of claim 1 , wherein the at least one unlicensed carrier is selected based on the one or more SLRBs being configured with a PBR greater than the configured PBR threshold.

3. The method of claim 1 , wherein the at least one unlicensed carrier is selected based on a buffer status associated with the one or more SLRBs being greater than the configured buffer status threshold for a configured period of time.

4. The method of claim 1 , wherein the at least one unlicensed carrier is selected based on a minimum CBR of the at least one licensed carrier being greater than the configured CBR threshold.

5. The method of claim 1 , wherein the at least one unlicensed carrier is selected based on a cast type for transmission of the data not being a broadcast type.

6. The method of claim 1 , wherein selecting at least one licensed carrier and at least one unlicensed carrier is further based on a number of physical sidelink feedback channel (PSFCH) resources configured for the respective carriers.

7. The method of claim 1 , wherein selecting the at least one licensed carrier is based on a first set of conditions and selecting the at least one unlicensed carrier is based on a second set of conditions, different than the first set of conditions.

8. The method of claim 7, wherein the first set of conditions and the second set of conditions related to at least one of a bearer configuration, resource pool configuration, QoS parameter, listen- before-talk (LBT) failure, hybrid automatic repeat request (HARQ) feedback mode, received signal strength indicator (RSSI).

9. The method of claim 7, wherein selecting at least one licensed carrier and at least on unlicensed carrier is based on a ratio of licensed carriers to unlicensed carriers.

10. A wireless transmit and receive unit (WTRU) comprising: a transceiver and a processor in communication with the transceiver, the transceiver and processor configured to: receive configuration information including one or more thresholds for prioritized bit rate (PBR), buffer status or channel busy ratio (CBR), to determine whether to allow transmission on an unlicensed carrier for a sidelink (SL) radio bearer (SLRB); for a destination layer 2 (L2) ID configured for transmission on both licensed and unlicensed carriers, establish one or more SLRBs for transmission for the L2 ID based on established quality of service (QoS) flows; select at least one licensed carrier and at least one unlicensed carrier for multicarrier transmission of SL data for the L2 ID based on the configured one or more thresholds; and transmit data on each of the selected carriers for the L2 ID to a peer WTRU.

11. The WTRU of claim 10, wherein the at least one unlicensed carrier is selected based on the one or more SLRBs being configured with a PBR greater than the configured PBR threshold.

12. The WTRU of claim 10, wherein the at least one unlicensed carrier is selected based on a buffer status associated with the one or more SLRBs being greater than the configured buffer status threshold for a configured period of time.

13. The WTRU of claim 10, wherein the at least one unlicensed carrier is selected based on a minimum CBR of the at least one licensed carrier being greater than the configured CBR threshold.

14. The WTRU of claim 10, wherein the at least one unlicensed carrier is selected based on a cast type for transmission of the data not being a broadcast type.

15. The WTRU of claim 10, wherein selecting at least one licensed carrier and at least one unlicensed carrier is further based on a number of physical sidelink feedback channel (PSFCH) resources configured for the respective carriers.

16. The WTRU of claim 10, wherein selecting the at least one licensed carrier is based on a first set of conditions and selecting the at least one unlicensed carrier is based on a second set of conditions different than the first set of conditions.

17. The WTRU of claim 16, wherein the first set of conditions and the second set of conditions related to at least one of a bearer configuration, resource pool configuration, QoS parameter, listen- before-talk (LBT) failure, hybrid automatic repeat request (HARQ) feedback mode, received signal strength indicator (RSSI).

18. The WTRU of claim 10, wherein selecting at least one licensed carrier and at least on unlicensed carrier is based on a ratio of licensed carriers to unlicensed carriers.