Measurement-Based Carrier Selection in Multi-Carrier Sidelink

Abstract

A wireless transmit / receive unit (WTRU) may be configured to prioritize carriers with available sensing results from inter-UE coordination (IUC) during carrier selection and logical channel prioritization (LCP). The WTRU may be configured to identify carriers and determine that the carriers have associated IUC information, which may include sensing measurements. The WTRU may select a carrier from multiple carriers based on the carriers with associated IUC information. The WTRU may prioritize selection of a carrier over other carriers in the selection based on the IUC information associated with the carrier. The WTRU may associate a first CBR threshold with the carrier based on the IUC information associated with the carrier. The WTRU may select data for transmission based on the first CBR threshold associated with the carrier.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of U.S. Provisional Patent Application No. 63 / 395,475, filed August 5, 2022, the disclosure of which is incorporated herein by reference in its entirety. [Background technology]

[0002] Mobile communications using radio communications continues to evolve. The fifth generation is sometimes referred to as 5G. Previous (traditional) generations of mobile communications may be, for example, fourth generation (4G) long term evolution (LTE). Summary of the Invention

[0003] A system, method, and means for measurement-based carrier selection is disclosed.

[0004] A wireless transmit and receive unit (WTRU) may receive inter-UE coordination (IUC) information that may identify a first carrier and a second carrier and that may be associated with one of the carriers. The WTRU may receive data for transmission, where the data may have an associated data priority. On the condition that the data priority exceeds a priority threshold and the WTRU determines that the first carrier is associated with the IUC information, the WTRU may determine that a first channel busy ratio (CBR) associated with the first carrier meets a first CBR threshold and may determine that the first carrier is available for selection.

[0005] If the data priority exceeds the priority threshold and the WTRU determines that the second carrier is not associated with the IUC information, the WTRU may determine that the second CBR associated with the second carrier satisfies the second CBR threshold and may determine that the second carrier is available for selection. The first CBR threshold may be higher than the second CBR threshold.

[0006] The WTRU may select a sidelink grant on a first carrier. Provided that the WTRU determines that a first CBR associated with the first carrier is above a second CBR threshold, the WTRU may select data associated with a data priority above a priority threshold for transmission on the first carrier. Provided that the WTRU determines that the first CBR associated with the first carrier is not above the second CBR threshold, the WTRU may select data from the highest priority channel for transmission on the first carrier. The WTRU may send the selected data using a sidelink grant on the first carrier.

[0007] The WTRU may determine that a third carrier is associated with the IUC information and that a fourth carrier is not associated with the IUC information. The WTRU may receive second data having an associated second data priority. On a condition that the WTRU determines that the second data priority is less than a priority threshold, the WTRU may determine that the third carrier is available for selection based on a third CBR associated with the third carrier satisfying the second CBR threshold. The WTRU may determine that the fourth carrier is available for selection based on a fourth CBR associated with the fourth carrier satisfying the second CBR threshold. The WTRU may select a sidelink grant on the third carrier and may send data of any priority on the third carrier.

[0008] The WTRU may be configured to prioritize carriers that have available sensing results from the IUC during carrier selection and logical channel prioritization (LCP). The WTRU may be configured to identify a carrier and determine that the carrier has associated IUC information that may include sensing measurements. The WTRU may select a carrier from multiple carriers based on the carrier that has associated IUC information. The WTRU may prioritize selection of a carrier over other carriers in the selection based on the IUC information associated with the carrier.

[0009] The WTRU may operate in an autonomous resource allocation mode, e.g., Mode 2. The WTRU may receive new data on a logical channel. In response to receiving the data, the WTRU may trigger carrier and resource reselection for a new HARQ process. The WTRU may determine whether it has received, e.g., recently received, an IUC that includes a set of preferred / non-preferred resources for one or more carriers.

[0010] The WTRU may determine a priority associated with the newly received data. If the WTRU determines that the priority of the data may exceed a threshold, the WTRU may determine to use a different (e.g., higher) CBR threshold for carrier selection for carriers for which IUC information may be available compared to carriers for which IUC information may not be available. If the WTRU determines that the priority of the data may not exceed the threshold, the WTRU may determine to use a single, e.g., the same, CBR threshold for carrier selection for both carriers for which IUC information may be available and carriers for which IUC information may not be available.

[0011] The WTRU may be configured to start with a carrier for which IUC information may be available, and then select one or more allowed carriers in order of increasing CBR level. The WTRU may first select a carrier that has associated IUC information.

[0012] The WTRU may be configured to select a sidelink grant on a selected carrier. The WTRU may be configured to determine whether the grant occurs on a carrier with an associated CBR that may be higher than a threshold associated with a carrier that does not have associated IUC information. If the grant occurs on a carrier with an associated CBR that may be higher than a threshold associated with a carrier that does not have associated IUC information, the WTRU may select data from a highest priority logical channel that has available data and whose priority may be above the threshold. If the WTRU determines that the grant occurs on a carrier with an associated CBR that may not be higher than the threshold, the WTRU may determine to select data from a highest priority logical channel that has available data. [Brief explanation of the drawings]

[0013] [Figure 1A] FIG. 1 is a system diagram illustrating an example communication system in which one or more disclosed embodiments may be implemented. [Figure 1B] 1B is a system diagram illustrating an exemplary wireless transmit / receive unit (WTRU) that may be used within the communication system illustrated in FIG. 1A, according to one embodiment. [Figure 1C] 1A is a system diagram illustrating an example radio access network (RAN) and an example core network (CN) that may be used within the communication system illustrated in FIG. 1A, according to one embodiment. [Figure 1D]1B is a system diagram illustrating a further exemplary RAN and a further exemplary CN that may be used within the communication system illustrated in FIG. 1A, according to one embodiment. [Figure 2] FIG. 1 is a diagram of an example implementation of carrier selection. DETAILED DESCRIPTION OF THE INVENTION

[0014] A more detailed understanding may be had from the following description, given by way of example in conjunction with the accompanying drawings, in which:

[0015] 1A is a diagram illustrating an example communication system 100 in which one or more disclosed embodiments may be implemented. Communication system 100 may be a multiple-access system that provides content, such as voice, data, video, messaging, broadcasts, etc., to multiple wireless users. Communication system 100 may enable multiple wireless users to access such content through sharing of system resources, including wireless bandwidth. For example, the communication system 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-tailed unique word discrete Fourier transform (DFT) spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, filter bank multicarrier (FBMC), etc.

[0016] 1A, communications system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, RANs 104 / 113, CNs 106 / 115, public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, although it will be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of 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 "STA," may be configured to transmit and / or receive wireless signals and may include user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a mobile phone, 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 (IoT) device, a watch or other wearable device, a head-mounted display (HMD), a vehicle, a drone, a medical device and application (e.g., for remote surgery), an industrial device and application (e.g., a robot and / or other wireless device operating in an industrial and / or automated processing chain context), a consumer electronics device, a device operating on a commercial wireless network and / or an industrial wireless network, etc. Any of the WTRUs 102a, 102b, 102c, and 102d may be referred to interchangeably as a UE.

[0017] The communications system 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 communications networks, such as the CN 106 / 115, the Internet 110, and / or other networks 112. By way of example, the base stations 114a, 114b may be a Base Transceiver Station (BTS), a Node B, an eNodeB (eNB), a Home Node B, a Home eNodeB, a gNodeB (gNB), an NR Node B, a site controller, an Access Point (AP), a wireless router, etc. Although the base stations 114a, 114b are each depicted as a single element, it will be understood that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0018] 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 base station 114b may be configured to transmit and / or receive radio signals on one or more carrier frequencies, which may be referred to as a cell (not shown). These frequencies may be licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide wireless service coverage for a particular geographic area, which may be relatively fixed or may change over time. A cell may be further 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 transceiver for each sector of the cell. In one embodiment, the base station 114a may employ multiple-input multiple output (MIMO) technology and may utilize multiple transceivers per sector of the cell, for example, using beamforming to transmit and / or receive signals in desired spatial directions.

[0019] 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).

[0020] More specifically, as noted above, the communications system 100 may be a multiple-access system, but may employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, the base station 114 a and the WTRUs 102 a, 102 b, 102 c in the RAN 104 / 113 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 communications 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 Packet Access (HSUPA).

[0021] In one 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).

[0022] In one 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).

[0023] In one 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 jointly implement LTE radio access and NR radio access, e.g., using dual connectivity (DC) principles. Thus, the air interface utilized by the WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions sent to and from multiple types of base stations (e.g., eNBs and gNBs).

[0024] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement a wireless technology 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), or the like.

[0025] 1A may be, for example, a wireless router, a Home NodeB, a Home eNodeB, or an access point and may utilize any suitable RAT to facilitate wireless connectivity in a local area such as a business, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a road, etc. 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 one 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 establish a picocell or a femtocell using a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.). 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 need to access the Internet 110 through the CN 106 / 115.

[0026] The RAN 104 / 113 may communicate with the CN 106 / 115, which may be any type of network configured to provide voice, data, application, and / or voice over internet protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have various quality of service (QoS) requirements, such as different throughput, latency, error tolerance, reliability, data throughput, mobility, etc. The CN 106 / 115 may provide call control, billing services, mobile location-based services, prepaid 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 understood that the RAN 104 / 113 and / or the CN 106 / 115 may communicate directly or indirectly with other RANs employing the same RAT as the RAN 104 / 113 or a different RAT. For example, the CN 106 / 115, in addition to being connected to the RAN 104 / 113, which may utilize NR radio technology, may also communicate with another RAN (not shown) employing GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0027] 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 other networks 112. The PSTN 108 may include a circuit-switched telephone network providing plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices, which use common communication protocols such as the transmission control protocol (TCP), the user datagram protocol (UDP), and / or the internet protocol (IP) of the TCP / IP Internet protocol suite. The network 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, the network 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.

[0028] 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 a base station 114a, which may employ a cellular-based wireless technology, and a base station 114b, which may employ an IEEE 802.2 wireless technology.

[0029] 1B is a system diagram illustrating an example WTRU 102. As shown in FIG. 1B, the WTRU 102 may include, among other things, a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and / or other peripherals 138. It will be understood that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment.

[0030] The processor 118 may be a general-purpose processor, a special-purpose processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) circuit, any other type of integrated circuit (IC), a state machine, etc. The processor 118 may perform signal coding, data processing, power control, input / output processing, and / or any other 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. 1B depicts the processor 118 and the transceiver 120 as separate components, it will be understood that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0031] The transmit / receive element 122 may be configured to transmit or receive signals to or from a base station (e.g., 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 one embodiment, the transmit / receive element 122 may be an emitter / detector configured to transmit and / or receive IR signals, UV signals, 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 signals and light signals. It will be understood that the transmit / receive element 122 may be configured to transmit and / or receive any combination of wireless signals.

[0032] 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.

[0033] The transceiver 120 may be configured to modulate signals transmitted by the transmit / receive element 122 and demodulate signals 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 to enable the WTRU 102 to communicate via multiple RATs, such as, for example, NR and IEEE 802.11.

[0034] The processor 118 of the WTRU 102 may be coupled to and may receive user-entered data from a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light-emitting diode (OLED) display unit). The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. Additionally, the processor 118 may access information from and store data in any type of suitable memory, such as non-removable memory 130 and / or 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, etc. 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 home computer (not shown).

[0035] The processor 118 may receive power from the power source 134 and may be configured to distribute and / or control the power to other components in the WTRU 102. The power source 134 may be any suitable device for providing power to the WTRU 102. For example, the power source 134 may include one or more dry batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0036] The processor 118 may also be coupled to a GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to, or instead of, information from the GPS chipset 136, the WTRU 102 may receive location information from base stations (e.g., base stations 114a, 114b) over the air interface 116 and / or determine its location based on the timing of signals 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.

[0037] 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 electronic compass, a satellite transceiver, a digital camera (for photos and / or videos), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands-free headset, a Bluetooth module, a frequency modulated (FM) radio unit, a digital music player, a media player, a video game player module, an internet browser, a virtual reality and / or augmented reality (VR / AR) device, an activity tracker, etc. The peripheral device 138 may include one or more sensors, which may be one or more of a gyroscope, an accelerometer, a Hall effect sensor, a magnetometer, a direction 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.

[0038] The WTRU 102 may include a full-duplex radio where transmission and reception of some or all of the signals associated with a particular subframe (e.g., for both the UL (e.g., for transmission) and downlink (e.g., for reception)) may be parallel and / or simultaneous. The full-duplex radio may include an interference management unit to reduce and or substantially eliminate self-interference through either hardware (e.g., a choke) or signal processing via a processor (e.g., via a separate processor (not shown) or processor 118). In one embodiment, the WTRU 102 may include a half-duplex radio for transmission and reception of either some or all of the signals (e.g., associated with a particular subframe for either the UL (e.g., for transmission) or downlink (e.g., for reception)).

[0039] 1C is a system diagram illustrating the RAN 104 and the CN 106, according to one embodiment. As noted above, the RAN 104 may employ E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also communicate with the CN 106.

[0040] The RAN 104 may include eNode-Bs 160a, 160b, and 160c, although it will be understood that the RAN 104 may include any number of eNode-Bs while remaining consistent with an embodiment. The eNode-Bs 160a, 160b, and 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, and 102c over the air interface 116. In one embodiment, the eNode-Bs 160a, 160b, and 160c may implement MIMO technology. Thus, the eNode-B 160a may, for example, use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a.

[0041] 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, etc. As shown in FIG. 1C, the eNode-Bs 160a, 160b, 160c may communicate with each other via an X2 interface.

[0042] 1C may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. Although each of the foregoing elements is depicted as part of the CN 106, it will be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0043] 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 function as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, activating / deactivating bearers, selecting a particular serving gateway during initial attach of the WTRUs 102a, 102b, 102c, etc. 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.

[0044] The SGW 164 may be connected to each of the eNodeBs 160a, 160b, 160c in the RAN 104 via an S1 interface. The SGW 164 may generally route and forward user data packets to and from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions, such as anchoring the user plane during inter-eNodeB handovers, triggering paging when DL data is available to the WTRUs 102a, 102b, 102c, and managing and storing the context of the WTRUs 102a, 102b, 102c.

[0045] The SGW 164 may be connected to a 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.

[0046] 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 landline communications devices. For example, the CN 106 may include or 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. Additionally, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0047] Although the WTRU is illustrated in FIGS. 1A-1D as a wireless terminal, it is contemplated that in certain representative embodiments, such a terminal may use a wired communication interface (e.g., temporarily or permanently) with the communication network.

[0048] In a representative embodiment, the other network 112 may be a WLAN.

[0049] A WLAN in infrastructure Basic Service Set (BSS) mode may have an access point (AP) of the BSS and one or more stations (STAs) associated with the AP. The AP may have access to or interface with a Distribution System (DS) or another type of wired / wireless network that carries traffic within and / or outside the BSS. Traffic originating from outside the BSS to a STA may arrive through the AP and be delivered to the STA. Traffic originating from a STA to a destination outside the BSS may be sent to the AP to be delivered to the respective destination. Traffic between STAs within the BSS may be sent, for example, through the AP, where the source STA may send traffic to the AP, and the AP may deliver the traffic to the destination STA. Traffic between STAs within the BSS may be considered and / or referred to as peer-to-peer traffic. Peer-to-peer traffic may be sent between (e.g., directly between) a source STA and a destination STA using a direct link setup (DLS). In certain representative embodiments, the DLS may use 802.11e DLS or 802.11z tunneled DLS (TDLS). A WLAN using an Independent BSS (IBSS) mode may not have an AP, and STAs within or using the IBSS (e.g., all of the STAs) may communicate directly with each other. The IBSS mode of communication may be referred to herein as an "ad hoc" communication mode.

[0050] When using the 802.11ac infrastructure mode of operation or a similar mode of operation, an AP may transmit beacons on a fixed channel, such as a primary channel. The primary channel may be a fixed width (e.g., a 20 MHz wide bandwidth) or a width that is dynamically set via signaling. The primary channel may be the operating channel of the BSS, but may also be used by STAs to establish a connection with the AP. In certain representative embodiments, for example, in an 802.11 system, Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA) may be implemented. With CSMA / CA, STAs (e.g., all STAs), including the AP, may sense the primary channel. If a particular STA senses / detects and / or determines that the primary channel is busy, the particular STA may back off. One STA (e.g., only one station) may transmit in a given BSS at any given time.

[0051] High Throughput (HT) STAs may use 40 MHz wide channels for communication, which may be formed, for example, through a combination of a primary 20 MHz channel and adjacent or non-adjacent 20 MHz channels.

[0052] A Very High Throughput (VHT) STA may support channels with widths of 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz. A 40 MHz and / or 80 MHz channel may be formed by combining multiple contiguous 20 MHz channels. A 160 MHz channel may be formed by combining eight 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, after channel encoding, the data may pass through a segment parser that may separate the data into two streams. Inverse Fast Fourier Transform (IFFT) processing and time-domain processing may be performed separately on each stream. The streams may be mapped to two 80 MHz channels, and the data may be transmitted by the transmitting STA. At the receiver of the receiving STA, the operations described above for the 80+80 configuration may be reversed, and the combined data may be sent to Medium Access Control (MAC).

[0053] Sub-1 GHz operating modes are supported by 802.11af and 802.11ah. Channel operating bandwidths and carriers are reduced in 802.11af and 802.11ah compared to those used in 802.11n and 802.11ac. 802.11af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in the TV White Space (TVWS) spectrum, while 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum. According to representative embodiments, 802.11ah may support meter-type control / machine-type communications, such as MTC devices, within a macro coverage area. MTC devices may have limited capabilities, including, for example, support for (e.g., only support for) certain specific and / or limited bandwidths. MTC devices may include batteries with above-threshold battery life (e.g., to maintain very long battery life).

[0054] WLAN systems that can support multiple channels and channel bandwidths, such as 802.11n, 802.11ac, 802.11af, and 802.11ah, include a channel that can be designated as a primary channel. The primary channel can have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel can be configured and / or limited by the STAs among all STAs operating in the BSS that support the minimum bandwidth operating mode. In an 802.11ah embodiment, the primary channel can be 1 MHz wide for STAs (e.g., MTC-type devices) that support (e.g., only) the 1 MHz mode, even if the AP and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and / or other channel bandwidth operating modes. Carrier sensing and / or Network Allocation Vector (NAV) configuration can depend on the status of the primary channel. For example, if the primary channel is busy due to STAs (that support (e.g., only) 1 MHz operating mode) transmitting to the AP, the entire available frequency band may be considered busy, even though most of the frequency band may remain idle and available.

[0055] In the United States, the available frequency band that can be used by 802.11ah is 902MHz to 928MHz. In South Korea, the available frequency band is 917.5MHz to 923.5MHz. In Japan, the available frequency band is 916.5MHz to 927.5MHz. The total bandwidth available for 802.11ah is 6MHz to 26MHz depending on the country code.

[0056] 1D is a system diagram illustrating the RAN 113 and the CN 115, according to one embodiment. As mentioned above, the RAN 113 may use NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 113 may also communicate with the CN 115.

[0057] The RAN 113 may include gNBs 180a, 180b, and 180c, although it will be understood that the RAN 113 may include any number of gNBs while remaining consistent with an embodiment. The gNBs 180a, 180b, and 180c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, and 102c over the air interface 116. In an embodiment, the gNBs 180a, 180b, and 180c may implement MIMO technology. For example, the gNB 180a, 180b may transmit signals to and / or receive signals from the gNBs 180a, 180b, and 180c using beamforming. Thus, the gNB 180a may transmit and / or receive wireless signals to and / or from the WTRU 102a using, for example, multiple antennas. In one 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 one embodiment, the gNBs 180a, 180b, 180c may implement Coordinated Multi-Point (CoMP) technology. For example, the WTRU 102a may receive coordinated transmissions from the gNBs 180a and 180b (and / or 180c).

[0058] The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using transmissions associated with 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 the gNBs 180a, 180b, 180c using subframes or transmission time intervals (TTIs) of different or scalable lengths (e.g., including different numbers of OFDM symbols and / or lasting different lengths of absolute time).

[0059] 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 a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c without accessing another RAN (e.g., eNode-Bs 160a, 160b, 160c, etc.). In a standalone configuration, the WTRUs 102a, 102b, 102c may utilize one or more of the gNBs 180a, 180b, 180c as mobility anchor points. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using signals in unlicensed bands. In a non-standalone configuration, the WTRUs 102a, 102b, 102c may communicate with and connect to gNBs 180a, 180b, 180c while also communicating with and connecting to another RAN, such as eNode-Bs 160a, 160b, 160c. For example, the 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 a non-standalone configuration, the eNode-Bs 160a, 160b, 160c may act as mobility anchors for the WTRUs 102a, 102b, 102c, and the gNBs 180a, 180b, 180c may provide additional coverage and / or throughput for serving the WTRUs 102a, 102b, 102c.

[0060] 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 for network slicing, dual connectivity, interworking between NR and E-UTRA, routing of user plane data to User Plane Functions (UPFs) 184a, 184b, routing of control plane information to Access and Mobility Management Functions (AMFs) 182a, 182b, etc. As shown in FIG. 1D, the gNBs 180a, 180b, 180c may communicate with each other via an Xn interface.

[0061] 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 each of the foregoing elements is depicted as part of the CN 115, it will be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0062] 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 function as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, supporting network slicing (e.g., handling different PDU sessions with different requirements), selecting a particular SMF 183a, 183b, managing registration areas, terminating NAS signaling, mobility management, etc. The network slicing may be used by the AMF 182a, 182b to customize the CN support of the WTRUs 102a, 102b, 102c based on the type of service utilizing the 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, etc. The AMF 162 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.

[0063] The SMFs 183a and 183b may be connected to the AMFs 182a and 182b in the CN 115 via an N11 interface. The SMFs 183a and 183b may also be connected to the UPFs 184a and 184b in the CN 115 via an N4 interface. The SMFs 183a and 183b may select and control the UPFs 184a and 184b and configure the routing of traffic through the UPFs 184a and 184b. The SMFs 183a and 183b may perform other functions such as managing and assigning IP addresses for UEs, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notification, etc. The PDU session type may be IP-based, non-IP-based, Ethernet-based, etc.

[0064] The UPFs 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 UPFs 184, 184b may perform other functions such as routing and forwarding packets, enforcing user plane policy, supporting multi-homed PDU sessions, handling user plane QoS, buffering downlink packets, providing mobility anchoring, etc.

[0065] The CN 115 may facilitate communication with other networks. For example, the CN 115 may include or communicate with an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that acts as an interface between the CN 115 and the PSTN 108. Additionally, the CN 115 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, 102c may be connected to local data networks (DNs) 185a, 185b through the UPFs 184a, 184b via an N3 interface to the UPFs 184a, 184b and an N6 interface between the UPFs 184a, 184b and the DNs 185a, 185b.

[0066] 1A-1D and their corresponding descriptions, one or more or all of the functions described herein with respect to one or more of the WTRUs 102a-d, base stations 114a and 114b, eNode-Bs 160a-c, MME 162, SGW 164, PGW 166, gNBs 180a-c, AMFs 182a and 182b, UPFs 184a and 184b, SMFs 183a and 183b, DNs 185a and 185b, and / or any other devices 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 simulate network and / or WTRU functions.

[0067] The emulation devices may be designed to implement one or more tests of other devices in a lab environment and / or a carrier network environment. For example, one or more emulation devices may perform one or more or all functions while fully or partially implemented and / or deployed as part of a wired and / or wireless communication network to test other devices in the communication network. One or more emulation devices may perform one or more or all functions while temporarily implemented / deployed as part of a wired and / or wireless communication network. The emulation devices may be directly coupled to another device for testing purposes and / or may perform testing using wireless communication over the air.

[0068] One or more emulation devices may perform one or more functions, inclusive, while not being implemented / deployed as part of a wired and / or wireless communication network. For example, the emulation devices may be utilized in test scenarios in a test lab and / or in an undeployed (e.g., test) wired and / or wireless communication network to implement testing of one or more components. One or more emulation devices may be test equipment. Direct RF coupling and / or wireless communication via RF circuitry (which may include, e.g., one or more antennas) may be used by the emulation devices to transmit and / or receive data.

[0069] This application discloses measurement-based carrier selection in a multi-carrier sidelink. The carrier selection may be applicable to new radio (NR) vehicle-to-everything (V2X) communications. A wireless transmit / receive unit (WTRU) may be configured to prioritize carriers with available sensing results during carrier selection, e.g., from inter-UE coordination (IUC) and logical channel prioritization (LCP), e.g., of FIG. 2 . The WTRU may be configured to identify a carrier and determine that the carrier has associated IUC information, which may include sensing measurements. The WTRU may select a carrier from multiple carriers based on the carrier with associated IUC information. The WTRU may prioritize selection of the carrier over other carriers in the selection based on the IUC information associated with the carrier. The WTRU may associate a first CBR threshold with the carrier based on the IUC information associated with the carrier. The WTRU may select a logical channel and data for transmission from the logical channel based on the first CBR threshold associated with the carrier.

[0070] A WTRU may receive data for transmission, where the data may have an associated data priority. On a condition that the data priority exceeds a priority threshold and the WTRU determines that a first carrier is associated with IUC information, the WTRU may determine that a first channel busy ratio (CBR) associated with the first carrier satisfies a first CBR threshold and may determine that the first carrier is available for selection. On a condition that the data priority exceeds a priority threshold and the WTRU determines that a second carrier is not associated with IUC information, the WTRU may determine that a second CBR associated with the second carrier satisfies a second CBR threshold and may determine that the second carrier is available for selection. The first CBR threshold may be higher than the second CBR threshold. The WTRU may select a sidelink grant on the first carrier. On a condition that the WTRU determines that the first CBR associated with the first carrier exceeds a second CBR threshold, the WTRU may select data associated with a data priority that exceeds the priority threshold for transmission on the first carrier. The WTRU may select data from the highest priority channel for transmission on the first carrier, provided that the WTRU determines that the first CBR associated with the first carrier does not exceed a second CBR threshold. The WTRU may send the selected data using a sidelink grant on the first carrier.

[0071] Vehicular communication may be a communication mode in which WTRUs can communicate with each other (e.g., directly with each other). Two scenarios for V2X operation may include: an in-coverage scenario and an out-of-coverage scenario. For the in-coverage scenario, the WTRU may receive assistance from the network and start transmitting and receiving V2X messages. For the out-of-coverage scenario, the WTRU may start transmitting and receiving V2X messages using pre-configured parameters.

[0072] V2X communication may relate to device-to-device (D2D) communication. V2X communication services may comprise (e.g., consist of) the following types (e.g., four different types): V2V (vehicle-to-vehicle), V2I (vehicle-to-infrastructure), V2N (vehicle-to-network), and V2P (vehicle-to-pedestrian). V2V (vehicle-to-vehicle) communication may involve vehicle WTRUs communicating with each other (e.g., directly with each other). V2I (vehicle-to-infrastructure) communication may involve vehicle WTRUs communicating with an RSU / eNB. V2N (vehicle-to-network) communication may include vehicle WTRUs communicating with a core network. V2P (vehicle-to-pedestrian) communication may involve vehicle WTRUs communicating with a WTRU that may be associated with a condition, e.g., a special condition, such as low battery capacity.

[0073] V2X communication may involve resource allocation. LTE may define two modes of operation for V2X communication. The first mode may be Mode 3, in which the network can provide a scheduling assignment for V2X sidelink transmissions to the WTRU. The second mode may be Mode 4, in which the WTRU can select (e.g., autonomously select) resources from a configured / preconfigured resource pool. V2X LTE may define two categories of resource pools. The first category may include a receive pool that can be monitored to receive V2X transmissions. The second category may include a V2X transmit pool that can be used by the WTRU to select transmission resources in Mode 4. The transmit pool may or may not be used by a WTRU configured in Mode 3.

[0074] In LTE, the resource pool may be semi-statically signaled to the WTRU via RRC signaling. In Mode 4, the WTRU may use sensing before selecting resources from the RRC-configured transmission pool. LTE V2X may or may not support dynamic resource pool reconfiguration. The pool configuration may be, e.g., only, conveyed via SIBs and / or dedicated RRC signaling.

[0075] New Radio (NR) may provide V2X resource allocation. NR may inherit two modes of resource allocation from LTE. Mode 1 resource allocation may correspond to scheduled resource allocation for the gNB. Mode 2 resource allocation may correspond to autonomous resource allocation for the WTRU. The concepts of resource pooling and sensing for Mode 2 resource allocation may also be inherited from LTE.

[0076] Multi-carrier SL transmission may be provided. Carrier aggregation (CA) in the sidelink may be supported for V2X sidelink communications. It may apply to both in-coverage and out-of-coverage WTRUs. For CA in the sidelink, neither a primary nor a secondary component carrier may be defined. Each configured, e.g., (pre-)configured, resource pool for transmitting or receiving V2X sidelink communications may be associated with a single carrier. If a WTRU supporting CA in the sidelink uses autonomous resource selection, the WTRU may perform carrier selection and select one or more carriers to be used for V2X sidelink communication transmission. Carrier selection may be performed at the MAC layer depending on the CBR of the configured, e.g., (pre-)configured carriers for V2X sidelink communications and the PPPP(s) of the V2X messages to be transmitted. Carrier reselection may be performed when resource reselection may be triggered, or may be triggered per sidelink process. To avoid frequent switching across different carriers, the WTRU may continue to use a carrier that may already have been selected for transmission if the measured CBR on this carrier may be lower than a (pre-)configured threshold. The selected carriers, e.g., all selected carriers, may have the same synchronization reference or the same synchronization priority configuration. For a WTRU using autonomous resource selection, logical channel prioritization may be performed for sidelink resources on a carrier depending on the measured CBR on the carrier and the PPPP of the sidelink logical channels.

[0077] In LTE, carrier aggregation may be supported for broadcast, e.g., only for broadcast. The transmission carrier may be selected by the transmitting WTRU based on the carrier configured by higher layers for the service being transmitted (e.g., L2 ID) and by taking CBR into consideration to ensure equal use of resources.

[0078] Selection in LTE may or may not take into account some of the enhancements made for unicast selection and / or resource selection in NR. The TX WTRU may use (or rely on) IUC (Inter-UE Coordination) information when performing resource selection. The TX WTRU may not have access to IUCs on all available carriers. For WTRUs that may not be able to perform sensing on carriers, IUC availability can be taken into account for carrier selection. Measurements available in unicast (SL CQI, SL RSRP) may be used to avoid selecting an inappropriate carrier for SL transmission.

[0079] Configuration for SL carrier aggregation may be provided. Carrier selection may be performed by the SL WTRU. The WTRU may employ criteria for carrier selection. A Mode 2 WTRU may perform a carrier selection procedure. Carrier selection may include determining allowable carriers for transmission of a particular L2 ID or IDs. The WTRU may determine the actual carriers to be used for transmission of a particular L2 ID or IDs at a given time. The WTRU may select the actual carriers for transmission from the set of allowable carriers. Carrier selection may include determining a particular carrier that can be used for unicast versus a carrier that can be used for broadcast / groupcast. Selection may also include determining the amount of time that one or several carriers can be used for transmission and selecting a set of carriers (e.g., a preferred carrier set) to be transmitted to a peer WTRU (e.g., in a unicast link).

[0080] A Mode 2 WTRU may select the carrier(s) for SL transmission using one or a combination of the following criteria: L2 ID, CBR, QoS and / or SLRB settings, SL measurements reported by peer WTRUs, availability and / or nature of sensing results which may be from IUC information, licensed versus unlicensed carriers, LBT results on unlicensed carriers, cast type, HARQ feedback, presence of PSFCH on the carrier, and / or presence of one or more resource pools configured on the carrier that meet pool-specific criteria. With respect to the L2 ID, the WTRU may determine whether the L2 ID can be allowed to be used on a carrier based on information from higher layers.

[0081] The CBR may be used as a criterion for selecting a carrier for SL transmission. The WTRU may determine whether a carrier can be admitted for transmission based on whether the measured CBR is above a priority-dependent threshold. The WTRU may determine the particular carrier to be used for transmission by, e.g., first selecting, a carrier with a particular CBR, such as the lowest or highest CBR. The criterion for carrier selection may use the CBR in conjunction with other factors. The WTRU may use one factor for selection under a first CBR condition and another factor for selection under a second CBR condition. The WTRU may determine the CBR threshold used for selection based on the result of another criterion, such as determining the number of carriers selected based on the CBR.

[0082] The QoS and / or SLRB configuration may be used as criteria for selecting a carrier for SL transmission. The WTRU may determine a CBR threshold for determining the allowed carrier based on the priority of the data available for transmission. The specific carrier, the number of allowed carriers, the acceptable CBR range for selection, the period a carrier may be maintained before reselection is triggered, etc. may be configured in the SLRB configuration or may be determined based on parameters associated with the SLRB configuration or the QoS flow mapped to the SLRB. Whether the criteria for selection (e.g., availability of sensing results from the IUC) are applied may not depend on the priority associated with the data available for transmission.

[0083] SL measurements reported by a peer WTRU may be used as criteria for selecting a carrier for SL transmission. SL measurements may include, for example, currently received measurements received from a peer WTRU, such as SL RSRP, SL CQI, etc., as well as other measurements that may be considered in the future. The WTRU may select the carrier with the highest SL RSRP from the set of allowed carriers. If a carrier may currently be used for unicast and the reported SL RSRP may be above a threshold, the carrier may be retained regardless of the measured CBR on the carrier. If a carrier may currently be used for unicast and the reported SL RSRP may be above a threshold, whether the carrier may be an allowed carrier may not be determined by a different threshold compared to carriers that may not be used for unicast or that may not have a reported SL RSRP above the threshold.

[0084] In some cases, the availability and / or nature of sensing results from the IUC information may be used as criteria for selecting a carrier for SL transmission. The WTRU may select a carrier based on whether sensing results are available, which may be obtained by the WTRU's own sensing or from sensing performed by other WTRUs (and may be transmitted in the IUC information). The WTRU may select a carrier based on the nature of the available sensing results, for example, as follows: Whether the sensing result may be associated with partial sensing, short-term partial sensing, periodic partial sensing, full sensing, etc., or other types of sensing that may represent the amount of sensed resources; whether the sensing may originate from the WTRU itself or may be received from another WTRU in the IUC information; whether the sensing result received from the IUC information may be received as a result of a request or as a result of a peer WTRU autonomously transmitting a result; whether the sensing result may be associated with preferred resources, non-preferred resources, or resources that may result in contention (e.g., the type of IUC information transmitted); the number of WTRUs from which the TX WTRU may have received IUC information associated with a particular carrier, in some cases; whether the IUC information may be received from a WTRU with which the TX WTRU may have a unicast link; and / or whether the IUC information may be received from a WTRU from which the TX WTRU may transmit, possibly as a result of carrier selection, or whether the TX WTRU has selected a carrier to transmit on.

[0085] Licensed carrier versus unlicensed carrier may be used as a criterion for selecting a carrier for SL transmission. The WTRU may select a licensed carrier before an unlicensed carrier. The WTRU may select a licensed carrier based on a criterion if a first condition may be met (e.g., the CBR may exceed a first threshold), and may select a licensed carrier based on the same or different criterion if a second condition may be met (e.g., the CBR may exceed a second threshold). The WTRU may select a licensed carrier before an unlicensed carrier (or vice versa) based on whether some other condition / criterion may be met (e.g., based on priorities set in one or more SLRBs, based on whether the SLRBs are configured to prioritize licensed or unlicensed, etc.).

[0086] The results of the LBT on an unlicensed carrier may be used as a criterion for selecting a carrier for SL transmission. The WTRU may exclude a carrier from selection if the LBT fails on the carrier, fails multiple times, and / or fails over a period of time. The WTRU may select a carrier based on the number of LBT failures on the carrier, possibly over a period of time.

[0087] The cast types may be used as criteria for selecting a carrier for SL transmission. The WTRU may use a first criterion or a condition associated with the criterion to determine the carrier selected when data may be available for the first cast type, and may use a second criterion or a condition associated with the criterion to determine the carrier selected when data may be available for the second cast type.

[0088] The HARQ feedback may be used as a criterion for selecting a carrier for SL transmission. The WTRU may select a carrier based on the ACK / NACK ratio received on a carrier, possibly associated with a particular destination. If the WTRU can receive several NACKs associated with an L2 ID on a carrier, e.g., consecutively and / or over a period of time, the WTRU may possibly select another carrier for that particular L2 ID. The WTRU may exclude a carrier from selection following reception of several NACKs / DTX, e.g., consecutively and / or over a period of time. Such exclusion may be maintained for a period of time.

[0089] The presence of a PSFCH on a carrier may be used to select a carrier for SL transmission. The WTRU may select or prioritize for selection a carrier with configured PSFCH resources if the WTRU may be configured for a unicast link and / or groupcast with HARQ feedback, or if the WTRU may have a logical channel with valid HARQ feedback configured.

[0090] The existence of one or more resource pools configured on a carrier that meet pool-specific criteria may be used to select a carrier for SL transmission. A carrier may be selected / prioritized if at least one pool or all pools on a carrier meet the criteria.

[0091] The criteria mentioned herein and elsewhere may, in some cases, be used to prioritize certain carriers over other carriers in selections triggered by the availability of data for particular destinations, bearers, priorities, etc. In the context of carrier selection, priority may include one or more of the following: given equal selection criteria, the WTRU may select a preferred carrier over a non-preferred carrier; the WTRU may use more lenient conditions (e.g., a higher CBR threshold) when determining whether to exclude a carrier from the set of allowed carriers, the set of selected carriers, or the carriers used for transmission; the WTRU may include more than the maximum allowable number of carriers in its selected carrier list if the carrier may be prioritized; the WTRU may select a preferred carrier (e.g., select it first) during carrier selection (possibly in an order defined by another criterion) before considering non-preferred carriers for selection. Example embodiments of the above criteria used in prioritization during carrier selection may be described herein.

[0092] The use of a carrier in a unicast link may result in prioritization of that carrier. A WTRU may prioritize the selection of a carrier that has been determined to be used, can be used, or is already in use for communications with a peer WTRU in a unicast link. An advantage of such processing may be that it may avoid the need for reconfiguration of the peer WTRU, which may possibly involve PC5-RRC signaling and may also affect the WTRU's carrier selection.

[0093] The quality measured by a peer WTRU on a carrier in a unicast link may result in prioritization of that carrier. The WTRU may prioritize the selection of a carrier on which the WTRU may have received measurements (e.g., CQI) from a peer WTRU and, in some cases, where such measurements meet a criterion (e.g., the measurements may be above a threshold). The WTRU may prioritize the selection of a carrier if the number of reports, or the number of WTRUs reporting on a carrier, is likely to exceed a certain number, possibly with the measurement criterion met. An advantage of such processing may be that more efficient use of SL resources on carriers with higher CBRs may be permitted.

[0094] The availability of sensing results received from IUC information for a carrier may result in prioritization of that carrier. The WTRU may prioritize selection of a carrier on which the WTRU can receive IUC information from another WTRU, may have recently received IUC information from another WTRU, and / or can request IUC information from another WTRU. The WTRU may set a validity timer associated with the received IUC information, and during resource selection, the WTRU may prioritize carriers for which the WTRU can have valid IUC information associated with that carrier. An advantage of such processing may be that overall collisions on the sidelink may be reduced by prioritizing the use of carriers for which sensing results may apply.

[0095] Carrier selection or removal may be prohibited for a certain period of time. Carrier selection or carrier removal may be prohibited for a certain period of time, possibly after a carrier selection procedure. Following one of the triggers / conditions for carrier selection (e.g., a HARQ NACK), the WTRU may maintain the selected carrier for at least a certain period of time. Such maintenance may further be conditioned on other criteria herein being satisfied throughout the period. Similarly, following carrier removal in carrier selection, the WTRU may continue to remove the carrier for a certain period of time.

[0096] Carrier selection and / or reselection may be triggered. The WTRU may trigger a carrier (re)selection procedure on any combination of the following events (e.g., A as a condition of B): an event related to the IUC, an event related to receiving measurements from a peer WTRU, an event related to unicast link establishment / maintenance, an event related to HARQ feedback, an event related to establishment / release of new QoS flows and / or SLRBs, an event related to unauthorized operation, an event related to a change in CBR, and an event related to a change in SL DRX or Uu DRX settings.

[0097] Events related to the IUC may be used to trigger carrier selection and / or reselection. The WTRU may trigger carrier (re)selection when it receives an IUC possibly related to the currently used carrier. The WTRU may trigger carrier (re)selection when the received IUC may be associated with a carrier that may not have IUC information. The WTRU may trigger carrier (re)selection when the validity of IUC information associated with a carrier may have expired. The WTRU may trigger carrier (re)selection when it is unable to receive IUC information for a carrier (possibly upon expiration of a timer associated with the validity).

[0098] Events related to receiving measurements (e.g., CQI, RSRP) from a peer WTRU, possibly associated with some conditions on those measurements, may be used to trigger carrier (re)selection. A WTRU may trigger carrier (re)selection when it receives a CQI report from a peer WTRU, possibly with a CQI value above or below a threshold.

[0099] Events related to unicast link establishment / maintenance may be used to trigger carrier (re)selection. A WTRU may trigger carrier (re)selection following establishment or release of a unicast link with a peer WTRU. A WTRU may trigger carrier (re)selection following reception of a sidelink reconfiguration message from a peer WTRU, possibly (re)configuring a set of carriers. A WTRU may trigger carrier (re)selection following completion of a sidelink reconfiguration application received from a peer WTRU. A WTRU may trigger carrier (re)selection following transmission / reception of a reconfiguration success / failure message. A WTRU may trigger carrier (re)selection following detection of an SL-RLF with a peer WTRU.

[0100] Events related to HARQ feedback may be used to trigger carrier (re)selection. A WTRU may trigger carrier (re)selection following reception (possibly consecutive and / or possibly occurring within a period of time) of one or more HARQ NACKs and / or HARQ DTXs from a peer WTRU.

[0101] Events related to the establishment / release of new QoS flows and / or SLRBs may be used to trigger carrier (re)selection. The WTRU may trigger carrier (re)selection following the establishment of a new SLRB if such establishment / release may result in a change in the carrier selected based on the carrier selection criteria herein.

[0102] An event related to unauthorized operation may be used to trigger a carrier (re)selection. The WTRU may trigger a carrier (re)selection following one or more LBT failures on a carrier.

[0103] Events related to changes in CBR may be used to trigger carrier (re)selection. The WTRU may trigger carrier (re)selection following a change in the measured CBR, possibly for a particular carrier, possibly by a certain amount.

[0104] Events related to changes in the SL DRX configuration or the Uu DRX configuration may be used to trigger carrier (re)selection. A WTRU may trigger carrier (re)selection following a change in the SL DRX configuration, possibly between two WTRUs.

[0105] The LCP may take into account the criteria used for carrier selection. The WTRU may be configured with LCP restrictions associated with mapping data on logical channels to particular carriers. The conditions associated with applying such LCP restrictions may be related to the criteria applied for carrier selection. For example, a grant on a carrier may be used, e.g., only for a particular logical channel, if the carrier could have been selected due to the presence of data available from that logical channel. If the conditions for selecting a carrier are met for carrier selection due to the presence of data from a logical channel, the WTRU may multiplex data associated with that logical channel, e.g., only data, onto the grant of the associated selected carrier. If the WTRU prioritizes one carrier over another for a particular logical channel, then only data from that particular logical channel may be mapped to the preferred carrier. If the conditions for selecting a carrier are met for carrier selection due to the presence of data from a logical channel, the WTRU may multiplex data associated with that logical channel, e.g., only data, onto the grant if the carrier meets the same conditions. If a condition for carrier selection may be met due to the presence of data from a logical channel, but the condition may not be met if data was not present on that logical channel, and if a carrier may meet the condition for the presence of a logical channel, but may not meet the condition for the absence of a logical channel, the WTRU may multiplex data associated with the logical channel, e.g., only data, onto that carrier.

[0106] If the WTRU may have data available for an SLRB with a priority above the priority threshold, the WTRU may use a first CBR threshold for carriers for which the WTRU may have sensing results from another WTRU (e.g., may select a carrier if the measured CBR is below the first threshold) and a second CBR threshold for carriers for which the WTRU may not have sensing results from another WTRU (e.g., may select a carrier if the measured CBR is below the second threshold), e.g., as shown in Figure 2. In such a case, when the WTRU selects / receives a grant associated with a carrier with a CBR below the first threshold but potentially above the second threshold, the WTRU may multiplex data, e.g., only data, associated with logical channels with a priority above the priority threshold.

[0107] A wireless transmit / receive unit (WTRU) may comprise a processor configured to identify a first carrier among a plurality of carriers, determine that inter-UE coordination (IUC) information is associated with the first carrier, and select the first carrier from the plurality of carriers based on the IUC information. The processor configured to select the first carrier from the plurality of carriers based on the IUC information may be configured to prioritize the carriers based on the IUC information. The processor may be further configured to determine a second carrier among the plurality of carriers, receive data having an associated priority, and associate a first CBR threshold with the first carrier and a second CBR threshold with the second carrier based on the IUC associated with the first carrier, on the condition that the associated priority is above the threshold. The first CBR threshold may be higher than the second CBR threshold. The processor configured to select the first carrier from the plurality of carriers may be configured to select the first carrier based on the IUC information and the first CBR threshold. The processor may be further configured to select a sidelink grant on the first carrier, select data having a priority based on a first CBR threshold associated with the first carrier, and send the data on the first carrier.

[0108] The WTRU may use the first CBR threshold for carrier selection if the carrier can be used to transmit unicast data, otherwise it may use the second CBR threshold. If the WTRU selects a grant on a carrier where the CBR on the carrier meets the conditions for selection in the unicast case but does not meet the conditions for selection in the broadcast / groupcast case, the WTRU may select unicast data for transmission on the grant / carrier. If the conditions for both unicast and groupcast are met on a carrier, the WTRU may not apply LCP restrictions.

[0109] A WTRU in unicast may select a primary carrier or may be assigned a primary carrier. A WTRU with a unicast link may select a primary carrier or be assigned a primary carrier (e.g., by a peer WTRU, by the network, etc.) when multiple carriers are configured / used between the WTRUs. A WTRU may use the criteria herein to select a primary carrier from a set of carriers used for transmission of data on a unicast link. For example, a WTRU may select the carrier with the smallest CBR as the primary carrier. A WTRU may select the carrier with the best CQI as the primary carrier. A WTRU may select the carrier with the largest number of sensing results received from other WTRUs.

[0110] The WTRU may use the primary carrier, e.g., associated with the unicast link, to perform the following: transmit PC5-RRC signaling, transmit PC5-S signaling, use the primary carrier when a single carrier, e.g., a condition occurs where only a single carrier may be used (e.g., the average CBR across all carriers is above a threshold), the WTRU may use the CBR of the primary carrier as an indication of the CBR of the carrier associated with the unicast link, transmit IUC information on the primary carrier, and / or IUC information may be provided to a peer WTRU for the primary carrier.

[0111] A WTRU may use the same carrier that may be used as its primary carrier by a peer WTRU. A WTRU may be assigned a primary carrier by a peer WTRU. A WTRU may (re)select a primary carrier when performing a carrier (re)selection procedure. The WTRU may, for example, alternatively be configured with a separate trigger (e.g., different from carrier (re)selection) for primary carrier determination.

[0112] Although the features and elements described herein are described in particular combinations, each feature or element may be used alone without the other features and elements of the preferred embodiments, or may be used in various combinations with or without the other features and elements.

[0113] The descriptions herein may be provided for illustrative purposes and in no way limit the applicability of the described systems, methods, and means to other radio technologies and / or radio technologies using different principles, when applicable. The term network in this disclosure may refer to one or more gNBs that may be associated with one or more Transmission / Reception Points (TRPs) and / or any other nodes in a radio access network.

[0114] While the implementations described herein may take into account 3GPP-specific protocols, it will be understood that the implementations described herein are not limited to this scenario and may be applicable to other wireless systems. For example, while the solutions described herein take into account LTE, LTE-A, New Radio (NR), or 5G-specific protocols, it will be understood that the solutions described herein are not limited to this scenario and may be applicable to other wireless systems.

[0115] The processes described herein may be implemented in a computer program, software, and / or firmware embodied 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 via wired and / or wireless connections) and / or computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, read-only memory (ROM), random-access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media 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.

Claims

1. 1. A wireless transmit / receive unit (WTRU), comprising: receiving data having an associated data priority; and, provided that the data priority is above a priority threshold and the first carrier is associated with Inter-UE Coordination (IUC) information; determining that a first channel busy ratio (CBR) associated with the first carrier meets a first CBR threshold; determining that the first carrier is available to be selected; provided that the data priority is above the priority threshold and a second carrier is not associated with IUC information; determining that a second CBR associated with the second carrier meets a second CBR threshold; A wireless transmit / receive unit (WTRU) comprising: a processor configured to determine that the second carrier is available for selection.

2. The WTRU of claim 1 , wherein the first CBR threshold is greater than the second CBR threshold.

3. The processor: selecting a sidelink grant on the first carrier; The WTRU of claim 1 or 2, further configured to select data associated with a data priority above the priority threshold for transmission on the first carrier.

4. The processor:

4. The WTRU of claim 3, further configured to send the data associated with a data priority above the priority threshold using the sidelink grant on the first carrier.

5. The processor:

4. The WTRU of claim 3, further configured to select data from a highest priority logical channel for transmission on the first carrier, provided that the first CBR associated with the first carrier does not exceed the second CBR threshold.

6. The WTRU of any one of claims 1 to 5, wherein the processor is further configured to receive the IUC information from a second WTRU.

7. The WTRU of claim 6 , wherein the processor is further configured to determine that the IUC information is received within a predetermined period of time.

8. The WTRU of claim 7 , wherein the processor is further configured to request the IUC information from the second WTRU.

9. The processor: determining that a third carrier is associated with the IUC information; receiving second data having an associated second data priority; 9. The WTRU of claim 1, further configured to determine that the third carrier is available for selection based on a third CBR associated with the third carrier satisfying the second CBR threshold, provided that the second data priority is below the priority threshold.

10. The processor: determining that the fourth carrier is not associated with the IUC information; receiving third data having a third data priority associated therewith; 10. The WTRU of claim 1, further configured to determine that the fourth carrier is available for selection based on a fourth CBR associated with the fourth carrier satisfying the second CBR threshold, provided that the third data priority is below the priority threshold.

11. 1. A method for career selection, comprising: receiving data having an associated data priority; and, provided that the data priority is above a priority threshold and the first carrier is associated with Inter-UE Coordination (IUC) information; determining that a first channel busy ratio (CBR) associated with the first carrier meets a first CBR threshold; determining that the first carrier is available to be selected; provided that the data priority is above the priority threshold and a second carrier is not associated with IUC information; determining that a second CBR associated with the second carrier meets a second CBR threshold; determining that the second carrier is available to be selected.

12. The method of claim 11 , wherein the first CBR threshold is greater than the second CBR threshold.

13. selecting a sidelink grant on the first carrier; and 13. The method of claim 11 or 12, further comprising: selecting data associated with a data priority above the priority threshold for transmission on the first carrier.

14. 14. The method of claim 13, further comprising sending the data associated with a data priority above the priority threshold using the sidelink grant on the first carrier.

15. The processor:

14. The method of claim 13, further configured to select data from a highest priority logical channel for transmission on the first carrier, provided that the first CBR associated with the first carrier does not exceed the second CBR threshold.

16. receiving the IUC information from a second WTRU; The method of any one of claims 11 to 15, further comprising: determining that the IUC information was received within a predetermined period of time of a current time.

17. 1. A wireless transmit / receive unit (WTRU), comprising: receiving data having an associated data priority; and, provided that the data priority is above a priority threshold and the first carrier is associated with Inter-UE Coordination (IUC) information; determining that a first channel busy ratio (CBR) associated with the first carrier meets a first CBR threshold; determining that the first carrier is available to be selected; selecting a sidelink grant on the first carrier; A wireless transmit / receive unit (WTRU) comprising: a processor configured to select data associated with a data priority above the priority threshold for transmission on the first carrier.

18. The processor:

20. The WTRU of claim 17, further configured to send the data associated with a data priority above the priority threshold using the sidelink grant on the first carrier.

19. The WTRU of claim 17 or 18, wherein the processor is further configured to receive the IUC information from a second WTRU.

20. 20. The WTRU of claim 19, wherein the processor is further configured to determine that the IUC information is received within a predetermined period of time.

21. The WTRU of claim 19 , wherein the processor is further configured to request the IUC information from the second WTRU.

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