WO2025034901A1

WO2025034901A1 - Methods and systems for sidelink resource selection in shared uu and sidelink resources

Info

Publication number: WO2025034901A1
Application number: PCT/US2024/041337
Authority: WO
Inventors: Aata EL HAMSS; Tuong Hoang; Tao Deng; Moon Il Lee
Original assignee: InterDigital Patent Holdings Inc
Current assignee: InterDigital Patent Holdings Inc
Priority date: 2023-08-07
Filing date: 2024-08-07
Publication date: 2025-02-13
Anticipated expiration: 2026-02-07

Abstract

The present disclosure is directed to systems and methods for sidelink resource selection and management, particularly for shared Uu and sidelink resources. In one aspect, a device such as user equipment (UE) is configured to monitor downlink control channels in one or more slots also configured for sidelink transmissions in unlicensed channels. Upon detecting a transmission from a base station or gNB, the UE may send a transmission comprising a sidelink resource reservation to indicate the resource reserved by the gNB on the shared channel.

Description

METHODS AND SYSTEMS FOR SIDELINK RESOURCE SELECTION IN SHARED UU AND SIDELINK RESOURCES

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority to and the benefit of U S. Provisional Application Nos. 63/518,061 , entitled “Methods and Systems for Sidelink Resource Selection in Shared Uu and Sidelink Resources,” filed August 7, 2023; 63/518,065, entitled “Methods and Systems for Indirect Sidelink Resource Reservation,” filed August 7, 2023; and 63/518,067, entitled “Methods and Systems for Sidelink Resource Reservation,” filed August 7, 2023, the contents of each of which is incorporated herein by reference.

BACKGROUND

[0002] The unlicensed spectrum comprises frequency resources that are free for use by different operators or devices, including with different radio technologies. Devices may utilize the unlicensed spectrum if channel access protocols succeed, such as if a listen-before-talk (LBT) protocol is successful. When LBT fails, the device may back off or wait for a predetermined duration, and re-attempt to access the channel at a later time. The device may continue trying until the channel is idle, in some implementations. While this may provide additional bandwidth and throughput, congestion may cause delays for transmissions, and particularly may add uncertainty as to when a transmission will successfully be delivered. This may particularly impair real-time applications, such as voice or video conferencing, navigation, or other time sensitive systems.

[0003] In some 5G new radio (NR) implementations, a sidelink channel may be utilized. A sidelink channel allows a device, such as user equipment (UE) including mobile devices, to act as a proxy gateway for additional devices accessing a cellular network. This may allow the additional devices to access the network without their own direct connections to a base station or gNB.

[0004] In many implementations, NR sidelink supports two resource allocation modes: in a first mode, the gNB is responsible for allocating resources for sidelink transmissions; and in a second mode, the transmitter UE autonomously selects resources for sidelink transmissions. For mode 1, the UE requests resources for sidelink data transmission using a Buffer Status Report (BSR) in a medium access control (MAC) control element (CE) indicating the logical channel groups (LCG) for the requested grant. The UE then receives a downlink control information (DCI) message, scheduling a sidelink grant from the gNB. The DCI message indicates a physical uplink control channel (PUCCH) resource on which the UE will report the hybrid automatic repeat request (HARQ) status of the sidelink grant transmission For mode 2, the UE autonomously selects resources for transmission using a sensing technique. The resources semi-statically configured for sidelink transmission/reception are time division multiplexed (TDM) with Uu or air interface resources.

[0005] In cases where a device is using both a sidelink and NR in the unlicensed spectrum, to increase the resource utilization, the gNB and sidelink UE may share the same time and frequency resources and potentially can compete for the same resource. This raises an issue of how to avoid blocking/interference between Uu transmissions and sidelink UE transmissions in shared time/frequency resources (e.g. when a gNB is transmitting DL transmissions in the unlicensed spectrum, or a UE transmitting U L in the unlicensed spectrum). In particular, such instances may result in interference between the Uu and sidelink transmissions when the resources are shared for the licensed and unlicensed spectrum.

SUMMARY

[0006] The present disclosure is directed to systems and methods for sidelink resource selection and management, particularly for shared Uu and sidelink resources. In one aspect, a device such as user equipment (UE) is configured to monitor downlink control channels in one or more slots also configured for sidelink transmissions in unlicensed channels. Upon detecting a transmission from a base station or gNB, the UE may send a transmission comprising a sidelink resource reservation to indicate the resource reserved by the gNB on the shared channel.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] 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:

[0008] FIG. 1A is a system diagram illustrating an example communications system in which one or more disclosed embodiments may be implemented;

[0009] FIG. 1 B is a system diagram illustrating an example wireless transmit/receive unit (WTRU) that may be used within the communications system illustrated in FIG. 1A according to an embodiment;

[0010] 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;

[0011] 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. 1A according to an embodiment;

[0012] FIG. 2 is a flow chart of an embodiment of a method for sidelink resource management;

[0013] FIG. 3 is a flow chart of another embodiment of a method for sidelink resource management; and

[0014] FIG. 4 is a flow chart of another embodiment of a method for sidelink resource management. DETAILED DESCRIPTION

[0015] Table 1 is a non-exhaustive list of acronyms that may be used herein.

Table 1 [0016] 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), singlecarrier 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.

[0017] 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 itwill 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.

[0018] 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.

[0019] 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.

[0020] 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).

[0021] 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).

[0022] 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). [0023] 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.

[0024] 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).

[0025] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE 802.11 (i.e , Wireless Fidelity (WiFi), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), and the like. [0026] The base station 114b in FIG 1A 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 CN 106.

[0027] The RAN 104 may be in communication with the CN 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.

[0028] The CN 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.

[0029] 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 cellularbased radio technology, and with the base station 114b, which may employ an IEEE 802 radio technology.

[0030] FIG. 1 B is a system diagram illustrating an example WTRU 102. As shown in FIG. 1 B, the WTRU 102 may include a processor 118, a transceiver 120, a transmit/receive element 122, a speaker/microphone 124, a keypad 126, a display/touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and/or other peripherals 138, among others. It will be appreciated that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment.

[0031] 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.

[0032] 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.

[0033] Although the transmit/receive element 122 is depicted in FIG. 1 B as a single element, the WTRU 102 may include any number of transmit/receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit/receive elements 122 (e g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116. [0034] 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.

[0035] The processor 118 of the WTRU 102 may be coupled to, and may receive user input data from, the speaker/microphone 124, the keypad 126, and/or the display/touchpad 128 (e.g., a liquid crystal display (LCD) display unit or organic light-emitting diode (OLED) display unit) The processor 118 may also output user data to the speaker/microphone 124, the keypad 126, and/or the display/touchpad 128. In addition, the processor 118 may access information from, and store data in, any type of suitable memory, such as the non-removable memory 130 and/or the removable memory 132. The non-removable memory 130 may include random-access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, and the like. In other embodiments, the processor 118 may access information from, and store data in, memory that is not physically located on the WTRU 102, such as on a server or a home computer (not shown).

[0036] 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.

[0037] 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

[0038] 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.

[0039] 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 self-interference via either hardware (e.g., a choke) or signal processing via a processor (e.g., a separate processor (not shown) or via processor 118). In an embodiment, the 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)).

[0040] FIG. 1C 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 CN 106.

[0041] 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.

[0042] Each of the eNode-Bs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and/or DL, and the like. As shown in FIG. 1 C, the eNode-Bs 160a, 160b, 160c may communicate with one another over an X2 interface.

[0043] 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.

[0044] 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

[0045] 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.

[0046] 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. [0047] The CN 106 may facilitate communications with other networks For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional land-line communications devices. For example, the CN 106 may include, or may communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to the other networks 112, which may include other wired and/or wireless networks that are owned and/or operated by other service providers. [0048] Although the WTRU is described in FIGS. 1A-1 D as a wireless terminal, it is contemplated that in certain representative embodiments that such a terminal may use (e.g., temporarily or permanently) wired communication interfaces with the communication network.

[0049] In representative embodiments, the other network 112 may be a WLAN.

[0050] 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.

[0051] 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.

[0052] 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. [0053] Very High Throughput (VHT) STAs may support 20MHz, 40 MHz, 80 MHz, and/or 160 MHz wide channels The 40 MHz, and/or 80 MHz, channels may be formed by combining contiguous 20 MHz channels. A 160 MHz channel may be formed by combining 8 contiguous 20 MHz channels, or by combining two noncontiguous 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).

[0054] 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 802.11 af and 802.11ah relative to those used in 802.11n, and 802.11ac. 802.11 af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in the TV White Space (TVWS) spectrum, and 802.11 ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum. According to a representative embodiment, 802.11 ah may support Meter Type Control/Machine- Type Communications (MTC), such as MTC devices in a macro coverage area. MTC devices may have certain capabilities, for example, limited capabilities including support for (e.g , only support for) certain and/or limited bandwidths The MTC devices may include a battery with a battery life above a threshold (e.g., to maintain a very long battery life).

[0055] WLAN systems, which may support multiple channels, and channel bandwidths, such as 802 11 n, 802.11ac, 802.11 af, and 802.11 ah, include a channel which may be designated as the primary channel. The primary channel may have a bandwidth equal to the largest common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and/or limited by a STA, from among all STAs in operating in a BSS, which supports the smallest bandwidth operating mode. In the example of 802.11 ah, the primary channel may be 1 MHz wide for STAs (e.g., MTC type devices) that support (e.g., only support) a 1 MHz mode, even if the AP, and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and/or other channel bandwidth operating modes. Carrier sensing and/or Network Allocation Vector (NAV) settings may depend on the status of the primary channel. If the primary channel is busy, for example, due to a STA (which supports only a 1 MHz operating mode) transmitting to the AP, all available frequency bands may be considered busy even though a majority of the available frequency bands remains idle.

[0056] 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 802.11ah is 6 MHz to 26 MHz depending on the country code. [0057] FIG. 1 D 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 the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0058] 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).

[0059] 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).

[0060] 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.

[0061] 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.

[0062] The CN 106 shown in FIG. 1 D may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one Session Management Function (SMF) 183a, 183b, and possibly a Data Network (DN) 185a, 185b. While 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] In view of FIGs. 1A-1 D, and the corresponding description of FIGs. 1A-1 D, one or more, or all, of the functions described herein with regard to one or more of: WTRU 102a-d, Base Station 114a-b, eNode-B 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMF 182a-b, UPF 184a-b, SMF 183a-b, DN 185a-b, and/or any other device(s) described herein, may be performed by one or more emulation devices (not shown). The emulation devices may be one or more devices configured to emulate one or more, or all, of the functions described herein. For example, the emulation devices may be used to test other devices and/or to simulate network and/or WTRU functions.

[0068] 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.

[0069] 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.

[0070] In some 5G new radio (NR) implementations, a sidelink channel may be utilized. A sidelink channel allows a device, such as user equipment (UE) including mobile devices, to act as a proxy gateway for additional devices accessing a cellular network. This may allow the additional devices to access the network without their own direct connections to a base station or gNB.

[0071] In many implementations, NR sidelink supports two resource allocation modes: in a first mode, the gNB is responsible for allocating resources for sidelink transmissions; and in a second mode, the transmitter UE autonomously selects resources for sidelink transmissions. For mode 1 , the UE requests resources for sidelink data transmission using a Buffer Status Report (BSR) in a medium access control (MAC) control element (CE) indicating the logical channel groups (LCG) for the requested grant. The UE then receives a downlink control information (DCI) message, scheduling a sidelink grant from the gNB. The DCI message indicates a physical uplink control channel (PUCCH) resource on which the UE will report the hybrid automatic repeat request (HARQ) status of the sidelink grant transmission For mode 2, the UE autonomously selects resources for transmission using a sensing technique. The resources semi-statically configured for sidelink transmission/reception are time division multiplexed (TDM) with Uu or air interface resources.

[0072] In cases where a device is using both a sidelink and NR in the unlicensed spectrum, to increase the resource utilization, the gNB and sidelink UE may share the same time and frequency resources and potentially can compete for the same resource. This raises an issue of how to avoid blocking/interference between Uu transmissions and sidelink UE transmissions in shared time/frequency resources (e.g. when a gNB is transmitting DL transmissions in the unlicensed spectrum, or a UE transmitting U L in the unlicensed spectrum). In particular, such instances may result in interference between the Uu and sidelink transmissions when the resources are shared for the licensed and unlicensed spectrum.

[0073] The present disclosure is directed to systems and methods for sidelink resource selection and management, particularly for shared Uu and sidelink resources. In one aspect, a device such as user equipment (UE) is configured to monitor downlink control channels in one or more slots also configured for sidelink transmissions in unlicensed channels. Upon detecting a transmission from a base station or gNB, the UE may send a transmission comprising a sidelink resource reservation to indicate the resource reserved by the gNB on the shared channel.

[0074] In brief overview, a sidelink UE may be configured with a sidelink resource pool that spans multiple resource block (RB) sets in a frequency domain. The sidelink slot(s) can be used by either Uu (e.g., for PDCCH transmissions) or for sidelink transmissions. The sidelink UE is also configured to monitor a given frequency range or one or more channels of a control resource set (CORESET) within flexible slots that can be used by Uu and sidelink transmissions. PDCCH monitoring occasions can collide with PSSCH/PSCCH monitoring occasions (e.g. having the same or overlapping temporal durations, utilizing some or all of the same frequency ranges or channels, etc.).

[0075] The sidelink UE is pre-configured with one or more of the following triggers to transmit sidelink resource reservation for Uu transmission:

• a configuration by the network to transmit a “gNB resource reservation” and a sidelink control information (SCI) resource to transmit such a reservation;

• measured RSRP from the gNB is below a configured threshold;

• gNB indicates that sending sidelink resource reservation is activated. For example, the gNB is not capable of PC5 communication and indicates using the SIB(s) information that sending sidelink resource reservation is activated;

• SL UE is scheduled to transmit uplink and/or sidelink data transmission or receive downlink transmission; and/or

• measurements on sidelink channels indicate sidelink activity from other sidelink UEs. [0076] The sidelink UE can blindly detect the presence of PDCCH and/or sidelink transmissions. Upon detecting downlink control information (DOI) (e.g., group common DCI such as slot format indicators (SFI)) indicating the slot(s) to be used by the gNB for Uu transmission and when triggered to transmit a sidelink resource reservation based on the pre-configured triggers discussed above, the SL UE may send a resource reservation to other sidelink UEs using a SCI transmission after PDCCH reception. The SCI indicating resource reservation can be transmitted in a RB set that is different from the RB set(s) reserved by the gNB in some implementations, or in other implementations, the gNB can share its channel occupancy time (COT) with the SL UE to transmit such reservation. The broadcast sidelink resource reservation or SCI may indicate the set of slots to be used for Uu transmissions In some implementations, the sidelink UE can re-use an existing SCI format to transmit a sidelink resource reservation that indicates Uu transmission.

[0077] In more detail, the intention of having a sidelink UE transmit a sidelink resource reservation on a sidelink channel is to inform other sidelink UEs (e.g., Mode 2 sidelink UEs that are not scheduled by the gNB) that the gNB is using the channel, so that the other sidelink UEs can stop transmitting and the interference can be avoided. As the other sidelink UEs may not be in direct contact or communication with the gNB, they may not know when or what frequencies or channels the gNB is using, and thus may inadvertently schedule transmissions that interfere. Providing this resource reservation information in advance allows the devices to avoid utilizing those frequencies or channels or avoid broadcasts during a given time period.

[0078] In some implementations, a sidelink UE can be configured with a resource pool that has time slots overlapping with a Uu unlicensed link (i.e , overlapping with downlink and/or uplink slots). Such sidelink UEs can be under network coverage and being scheduled by the gNB to transmit on sidelink resources (e.g., Mode 1 UE in NR sidelink). For example, a sidelink UE can be configured with a resource pool that consists of: a first set of slots dedicated for sidelink transmission and/or reception; a second set of slots dedicated for downlink and/or uplink transmission; and a third set of slots that can be used by either sidelink transmission or downlink/uplink transmission (other implementations may be utlized). The transmission on the third set of slots can be accessed by the gNB, UE or sidelink UE(s). Such resource pools can span a single RB set or multiple RB sets in the frequency domain The UE can be configured using radio resource control (RRC) signalling with a first bitmap that indicates the first set of slots (i.e., dedicated for sidelink unlicensed transmission), second bitmap that indicates the second set of slots (i.e., dedicated for downlink/uplink unlicensed transmission), and third bitmap that indicates the third set of slots (i.e., shared between sidelink and downlink/uplink transmission). In another implementation, a sidelink UE can be configured with a resource pool that has all slots shared with Uu transmission (e.g., downlink and/or uplink transmission). The configuration of such resource pools can be in unlicensed spectrum or in licensed spectrum.

[0079] The UE can be configured with a CORESET/search space set for PDCCH monitoring that has symbol(s)/slot(s) within a set of slots shared between sidelink and downlink/uplink transmission. In some implementations, the search space set configuration in the frequency domain can include a group of interlaces (e g. channel resource allocation units) that are multiplexed with sidelink unlicensed interlaces. For example, interlaces may comprise any suitable number of consecutive or non-consecutive subcarriers in the frequency domain. Such interlaces configured for a search space set can be contiguous or non-contiguous interlaces. For example, in one such implementation, an RB set may have N interlaces in which a search space set can be configured in N1 interlaces, with N2 interlaces configured for sidelink transmission (N1+N2 being less or equal to N}. In another implementation, the search space set can be configured in some symbols of the slot while sidelink transmissions can be configured in different symbols of the same slot. For example, the first K symbols of a slot can be configured for search space set and the remaining symbols can configured for sidelink transmission/reception. In another implementation, the sidelink UE can be configured with a CO ESET/search space set that is overlapping with resources for sidelink transmission (i.e., not time or frequency division multiplexing within a slot). The UE can blindly monitor the presence of PDCCH and PSSCH/PSCCH in a resource that is configured for both Uu and sidelink transmission.

[0080] As discussed above, a sidelink UE can be configured to transmit a sidelink resource reservation on sidelink channels upon detecting gNB transmission on a shared resource between Uu and sidelink transmission. For example, when the sidelink UE detects a PDCCH transmission from the gNB, the SL UE may send a sidelink resource reservation to other sidelink UEs to indicate the resource reserved by the gNB. In some solutions, the sidelink UE can be pre-configured with one or more of the following conditions/triggers to transmit a sidelink resource reservation (i.e., sidelink resource reservation that indicates gNB’s transmission on sidelink channels):

• The sidelink UE may be configured by the network to transmit a sidelink resource reservation when the UE detects PDCCH transmission on a shared resource between Uu and sidelink;

• The sidelink UE may be configured by the network with sidelink control resource (e.g., PSSCH) to transmit a sidelink resource reservation;

• A measured RSRP from the gNB is above a configured threshold. For example, a sidelink UE may transmit a resource reservation on sidelink channels if the measured RSRP from downlink reference signals transmitted by the gNB is above a configured threshold. This can avoid cell edge UEs transmitting sidelink resource reservations because in the cell edge, interference may be tolerated;

• A gNB indication that it is not capable of PC5 (LTE-V2X) communication. If the gNB is not capable of PC5 communication, the sidelink UE can transmit a sidelink resource reservation. For example, the gNB can indicate in the broadcasted SIB(s) whether it is capable of PC5 communication;

• A gNB transmission enabling sidelink resource reservation. For example, the gNB can indicate in the broadcasted SIB(s) if sidelink resource reservation transmission is enabled;

• The sidelink UE is scheduled to receive a downlink data/control transmission;

• The sidelink UE is scheduled to transmit uplink and/or sidelink data transmission;

• Measurements on sidelink channels indicate sidelink activity from other sidelink UEs (e.g., a transmission from another sidelink UE). For example, a sidelink UE can be configured to measure a Channel Busy Ratio (CBR) on the sidelink channel and if the measured CBR is above a configured threshold, the UE can transmit a sidelink resource reservation if it detects a gNB transmission. The measurements on sidelink can include one or more of the following: Channel Busy Ratio (CBR) measurements; sidelink reference signal measurements for sidelink data/control transmission; and/or Sidelink control signaling measurements;

• The slots occupied by Uu transmission are overlapping with at least K sidelink slots, where K is a pre-configured number; and/or

• The number of slots occupied by Uu transmission are above a configured threshold.

[0081] Responsive to one or more triggers or conditions being satisfied, and/or responsive to receiving a downlink transmission from a gNB, a sidelink UE can be configured to transmit a sidelink resource reservation. The downlink transmission may include a PDCCH and/or PDSCH transmission. For example, the sidelink UE can receive a PDCCH transmission scheduling a data transmission on the sidelink or via an uplink transmission channel (PSSCH or PUSCH). The sidelink UE may then transmit a sidelink resource reservation to indicate that a sidelink resource is being reserved by a Uu transmission. In another example, the sidelink UE can receive a PDSCH transmission. The sidelink UE may then transmit a sidelink resource reservation to indicate that a sidelink resource is being reserved by the Uu transmission.

[0082] The sidelink UE can blindly detect the presence of PDCCH on the configured CORESET/search space set. Upon detecting a group common PDCCH or UE specific PDCCH, the UE determines the slot(s) that will be occupied by Uu transmission(s). For example, the sidelink UE can receive group common DCI indicating Slot Format Information (SFI). SFI carries the set of slots to be used for downlink and the set of slots to be used for uplink transmission. If one of the pre-configured conditions/triggers to transmit sidelink resource reservation is satisfied, the sidelink UE may send a resource reservation to other sidelink UEs using SCI transmission after receiving PDCCH.

[0083] In some implementations, a sidelink UE can include in a sidelink resource reservation an identification of the set of slots that will be used by the gNB for Uu transmission (either downlink or uplink). The sidelink UE can determine the set of slots to be used by the gNB from the group common DCI that is received from the gNB For example, the UE may receive a group common DCI carrying a slot format indicator that indicates the set of slots reserved by the gNB for Uu transmission. The UE may then transmit this information in the sidelink resource reservation to other sidelink UEs The UE can indicate in the sidelink resource reservation a number of slots that will be used by the gNB. In some implementations, the sidelink UE can be pre-configured with a number of possible slots and select specific slots based on the indicated number from SFI. The sidelink UE can use a bitmap in the sidelink resource reservation, where a bit value of “1” indicates Uu transmission and “0” indicate no Uu transmission (or vice versa, depending on implementation). The sidelink UE can use a broadcast destination ID to transmit such sidelink resource reservation, such as a broadcast destination ID dedicated to transmitting this type of sidelink resource reservation.

[0084] In some implementations, the sidelink UE can re-use an existing SCI format to transmit a sidelink resource reservation that indicates a Uu transmission. To differentiate between the existing SCI format that carries existing SCI information and a sidelink resource reservation for Uu transmission, in some implementations, a bitfield or flag in the existing SCI format information can indicate that the SCI format is carrying sidelink resource reservation from gNB. For example, a value of 1 in a predetermined bit can indicate that the SCI format is carrying sidelink resource reservation information for Uu transmission. A value of 0 can indicate that the SCI format is carrying the existing SCI format information (or vice versa). Such bitfield or predetermined bit can be pre-configured to the UE. In another solution, the sidelink UE can use the destination ID to differentiate between an existing SCI format information and an SCI format carrying sidelink resource reservation information for Uu transmission. For example, when a broadcast destination ID dedicated to transmit sidelink resource reservation for Uu is used by sidelink UE, other sidelink UEs can determine that the bitfield carried by the SCI are indicating a sidelink resource reservation for Uu.

[0085] In some implementations, a sidelink UE can be configured with a sidelink control resource (i.e., SCI resource) that can be used to transmit sidelink resource reservation that indicates Uu transmission. Such resource can be periodic and can be used depending on whether the sidelink UE is triggered to transmit the sidelink resource reservation. In another implementations, the sidelink UE can request the gNB to allocated SCI resource to transmit sidelink resource reservation that indicates Uu transmission. The SCI indicating resource reservation can be transmitted in different RB set from the RB set(s) reserved by the gNB or alternatively the gNB can share its channel occupancy time with the sidelink UE to transmit such a reservation. [0086] FIG. 2 is a flow chart of an implementation of a method 200 for resource reservation. At 202, a sidelink UE may be configured with a sidelink resource pool that spans single or multiple RB sets in the frequency domain The sidelink slot(s) can be used by either Uu (e.g., PDCCH transmission) or sidelink transmissions. As discussed above, the sidelink resource pool may have time slots overlapping with a Uu unlicensed link (i.e., overlapping with downlink and/or uplink slots). Such sidelink UEs can be under network coverage and being scheduled by the gNB to transmit on sidelink resources (e.g., Mode 1 UE in NR sidelink). The UE can be configured using radio resource control (RRC) signalling with a first bitmap that indicates the first set of slots (i.e., dedicated for sidelink unlicensed transmission), second bitmap that indicates the second set of slots (i.e., dedicated for downlink/u plin k unlicensed transmission), and third bitmap that indicates the third set of slots (i e., shared between sidelink and downlink/uplink transmission). In another implementation, a sidelink UE can be configured with a resource pool that has all slots shared with Uu transmission (e.g., downlink and/or uplink transmission). The configuration of such resource pools can be in unlicensed spectrum or in licensed spectrum.

[0087] At 204, the sidelink UE is configured with CORESET/search space monitoring within the flexible slots that can be used by Uu and sidelink transmissions PDCCH monitoring occasion can collide with PSSCH/PSCCH monitoring. The search space set configuration in the frequency domain can include a group of interlaces (e.g. channel resource allocation units) that are multiplexed with sidelink unlicensed interlace, and the interlace may comprise contiguous or non-contiguous subcarriers or resources.

[0088] At 206, the sidelink UE is pre-configured with one or more of the following triggers to transmit sidelink resource reservation for Uu transmission: configuration by the network to transmit “gNB resource reservation” and SCI resource to transmit such reservation; measured RSRP from the gNB is below a configured threshold; gNB indicates that sending sidelink resource reservation is activated. For example, the gNB is not capable of PC5 communication and indicates using the SIB(s) information that sending sidelink resource reservation is activated; SL UE is scheduled to transmit uplink and/or sidelink data transmission or receive downlink transmission; and/or Measurements on sidelink channels is indicating sidelink activity from other sidelink UEs. [0089] At 208, the sidelink UE blindly detects the presence of PDCCH and sidelink transmission, and at 210 determines whether a pre-configured trigger condition is satisfied. As discussed above, such trigger conditions may include detection of a PDCCH transmission on a shared resource; measured RSRP from a gNB exceeding a threshold; a gNB indication that it is not capable of PC5 communications; a gNB transmission enabling sidelink resource reservation; etc. Upon detecting DCI (e.g., group common DCI such as SFI) indicating the slot(s) to be used by the gNB for Uu transmission and triggered to transmit sidelink resource reservation based on the pre-configured triggers, at 212 the SL UE sends resource reservation to other sidelink UEs using SCI transmission after PDCCH reception. Otherwise, the UE may return to monitoring for trigger conditions and/or PDCCH and sidelink transmissions.

[0090] An SCI indicating resource reservation can be transmitted in different RB set from the RB set(s) reserved by the gNB or the gNB can share its COT with the SL UE to transmit such reservation. The SCI may be broadcasted and may indicate the set of slots to be used by Uu. As discussed above, in some implementations, the sidelink UE can re-use the existing SCI formats to transmit sidelink resource reservation that indicates Uu transmission.

[0091] Accordingly, the present disclosure is directed to systems and methods for sidelink resource selection and management, particularly for shared Uu and sidelink resources. In one aspect, a device such as user equipment (UE) is configured to monitor downlink control channels in one or more slots also configured for sidelink transmissions in unlicensed channels. Upon detecting a transmission from a base station or gNB, the UE may send a transmission comprising a sidelink resource reservation to indicate the resource reserved by the gNB on the shared channel.

[0092] In some implementations, the methods include monitoring, by a user equipment (UE) device, a communication channel with a base station, the communication channel shared for Uu transmissions and sidelink transmissions. The methods also include determining, by the UE, that a condition of the communication channel satisfies a sidelink resource reservation trigger. The methods also include detecting, by the UE, a transmission from the base station via the communication channel. The methods also include, responsive to detecting the transmission from the base station and the condition of the communication channel satisfying the sidelink resource reservation trigger, transmitting, by the UE to one or more additional UEs, data comprising a sidelink resource reservation.

[0093] In some implementations, the transmission from the base station comprises a physical downlink control channel (PDCCH) transmission. In some implementations, the transmission from the base station comprises an identification of a first one or more slots to be utilized for Uu transmission of a plurality of slots of the communication channel In a further implementation, the sidelink resource reservation identifies the first one or more slots.

[0094] In some implementations, determining that the condition of the communication channel satisfies the sidelink resource reservation trigger comprises detecting a resource reservation transmitted by the base station comprising a sidelink control information (SCI) resource. In some implementations, determining that the condition of the communication channel satisfies the sidelink resource reservation trigger comprises determining that a measured reference signal received power (RSRP) from the base station is below a threshold. In some implementations, determining that the condition of the communication channel satisfies the sidelink resource reservation trigger comprises detecting a transmission by the base station indicating that a side link resource reservation is activated. In some implementations, determining that the condition of the communication channel satisfies the sidelink resource reservation trigger comprises determining that a scheduled transmission time of the UE is occurring. In some implementations, determining that the condition of the communication channel satisfies the sidelink resource reservation trigger comprises detecting transmissions via the communication channel from the one or more additional UEs.

[0095] In another aspect, the present disclosure is directed to systems and methods for sidelink resource selection and management, particularly for shared Uu and sidelink resources. A sidelink UE is configured to monitor sidelink resource reservations transmitted by other sidelink UEs. Upon detecting a resource reservation in a sidelink channel which satisfies a pre-configured criteria, the SL UE indicates the resource reservation to the gNB using uplink control information and adjusts PDCCH monitoring accordingly.

[0096] In brief overview, a SL UE may be configured with sidelink resource pool that has multiple resource block (RB) sets in the frequency domain. Some sidelink slots can be used either by Uu (e.g., PDCCH transmission) or sidelink transmissions. The SL UE is also configured with one or more of the following criteria or triggers, satisfaction of which causes the UE to report a detected sidelink resource reservation to the gNB:

• High priority sidelink resource reservation;

• The reserved sidelink resource are overlapping with a pre-configured slots indicated by the gNB. The SL UE is pre-configured with slots to report if sidelink resource reservation is transmitted (e.g., the reserved sidelink resources are overlapping with PDCCH resources); and/or

• Measured RSRP from the UE transmitting a sidelink resource reservation is below a configured threshold.

[0097] Upon detecting sidelink control information (SCI) reserving a sidelink resource and determining that the pre-configured criteria or triggers have been satisfied, the SL UE reports to the gNB the reserved resources using an uplink control transmission. The SL UE may be configured with PUCCH resources in multiple RB set(s) to report the sidelink resource reservation to the gNB. In other implementations, the SL UE uses a PUCCH resource (in the same RB set or a different RB set from the RB set(s) reserved by sidelink UEs). SL UE determines which PUCCH resource to use based on the reserved RB set. [0098] In more detail, a UE may be (pre)configured with a SL resource pool and the frequency resources of the SL resource pool may be included in a SL BWP (pre)configured in a carrier. A UE may also be (pre)configured with a number of CORSETs for PDCCH monitoring in one or more DL BWP(s) (pre)configured in the same carrier. A licensed and/or unlicensed carrier shared by Uu and SL operation by a UE may be referred as a shared carrier, shared spectrum, shared bandwidth, or by similar terms. A shared carrier may be in a licensed or unlicensed spectrum.

[0099] In some implementations, a UE may be (pre)configured with some or all of the following information for PSCCH monitoring and decoding in the SL resource pool:

• A PSCCH time and frequency resource in a PSCCH monitoring slot; and

• One or more set(s) of PSCCH monitoring slots.

[0100] In some implementations, a PSCCH time resource may be a number of symbols in a PSCCH monitoring slot, e.g. the two symbols after the automatic gain control (AGC) symbol. A PSCCH frequency resource may be one or more RB(s) and/or sub-carrier(s) in a sub-channel, e g. RB(s) and/or sub-carrier(s) with the lowest RB and/or sub-carrier index(es) in a sub-channel. The number of RB(s) and/or sub-carriers of a sub-channel may be (pre)configured in a resource pool and/or a RB set.

[0101] In some implementations, a PSCCH frequency resource in a resource pool may overlap with the frequency allocation of CORESET. For example, a UE may be (pre)configured PSCCH and CORESET frequency resources in overlapping sub-carriers, RBs and/or sub-channels a same RB set.

[0102] In some implementations, a UE may be (pre)configured to monitor PSCCH and PDCCH in a same carrier, e.g. an unlicensed carrier and/or a licensed carrier. In PSCCH monitoring slot (pre)configuration, a SL slot in a SL resource pool may be assigned as one of the following three types of monitoring slots:

• PSCCH monitoring slot PpsccH.sbt. A UE may monitor PSCCH at the (pre)configured PSCCH resource in a PSCCH monitoring slot and decode SCI format when a PSCCH is detected;

• PDCCH monitoring slot PPDCCHJM A UE may monitor PDCCH at the (pre)configured COREST(s) in a PDCCH monitoring slot and decode a DCI format when a PDCCH is detected; or

• Flexible monitoring slot PPSCCH_PDCCH_SU. A UE may perform PSCCH and/or PDCCH monitoring as discussed above. A UE may dynamically determine which control information to monitor in the PSCCH and PDCCH monitoring slot based on (pre)configured conditions.

[0103] The assignment (pre)configuration may be indicated, e.g., using a bit map in a resource pool. In some implementations, a periodical pattern including different types of monitoring slots may be indicated in a resource pool In some implementations, a UE may determine to monitor a PSCCH in a flexible monitoring slot when the UE is indicated by gNB in a DCI to monitor PSCCH in the flexible monitoring slot. In another implementation, a UE may determine to monitor a PSCCH in a flexible monitoring slot when the flexible monitoring slot is reserved for SL transmission intended for the UE. The reserved SL transmission may be a semi-statically reserved initial transmission for a SL TB and/or an one-time reserved transmission for a re- transmission of a SL TB. In some implementations, a UE may determine to monitor a PSCCH in a flexible monitoring slot when the UE is indicated by gNB to skip PDCCH monitoring in the flexible monitoring slot.

[0104] In some implementations, when a UE detects a PSCCH in a PSCCH resource or monitoring slot, the UE may decode a SCI carried in a detected PSCCH and receive some or all of the following resource reservation information:

• One or more slot(s) reserved for future SL transmission(s): A UE may determine one or more reserved slot(s) based on an indication of a reservation interval, e.g. in terms of ms or number of slots;

• Frequency resource(s) reserved in the reserved slot(s): A UE may determine a reserved frequency resource based on an indication including a resource pool, one or more RB set(s), one or more sub-channel(s) , one or more RB(s) and/or one or more sub-carrier(s);

• A priority associated with the resource reservation: A UE may determine the priority associated with the resource reservation based on an L1 priority value indicated in the decoded SCI;

• A CAPC configuration associated with the resource reservation: A UE may determine the priority associated with the resource reservation based on an CAPC configuration indicated in the decoded SCI. A UE may determine a LBT Type 1 channel access using the indicated CAPC configuration may be performed to acquire channel access for transmission(s) within the reserved resources A UE may determine a maximum COT (mCOT) duration based on the indicated CAPC configuration;

• Remaining COT duration: A UE may determine the duration of further transmissions scheduled in the current COT after the detected PSCCH transmission. The remaining COT duration may be indicated in a unit of ms or slots;

• Transmit power parameter: A UE may determine one or more transmit power parameter(s) associated with resource reservation, i.e. the power parameters to be applied in the future SL transmission in the reserved resource(s). In one example, the transmit power parameter may be a transmit power value to be used for the future SL transmission. In another example, the transmit power parameter may be a (pre)configured transmit power mode Each transmit power mode may have a range of allowed transmit power setting, e.g., a maximum power. In a further example, a transmit power mode may indicate a (pre)configured fixed power, e.g. a very low power (VLP mode); and/or

• UE ID information: A UE may determine a UE ID, e.g., a SL source and/or destination ID associated with the resource reservation. The UE ID(s) may be indicated in the received SCI.

[0105] In some implementations, a UE may perform a SL RSRP measurement of the DMRS associated with the detected PSCCH and/or the associated PSSCH in the same transmission. A UE may associate the SL RSRP measurement with the reservation information received in the SCI carried in the detected PSCCH.

[0106] In some implementations, a UE may determine to perform a reporting of the received SL resource reservation information to gNB based on one or more of the following:

• The reserved slots in the received SL resource reservation; • The (pre)configured PDCCH monitoring slots and/or flexible monitoring slots;

• A priority value associated with the received SL resource reservation;

• A CAPC configuration associated with the resource reservation;

• One or more associated transmit power parameter(S) indicated in the received SL resource reservation;

• A SL RSRP measurement value associated with the received SL resource reservation;

• A DL RSRP measurement;

• A measured CBR value of the SL resource pool; and/or

• A (pre)configured time threshold for reporting transmission.

[0107] In one example, a UE determines an expected PSCCH and PDCCH monitoring conflict when one or more slots reserved for future SL transmission(s) may overlap with one or more (pre)configured PDCCH monitoring slots and/or flexible monitoring slots. A UE may not be able to monitor both PSCCH and PDCCH in the reserved slots. In this example, a UE may be triggered to perform a reporting of the received SL resource reservation information to gNB when one or more of the following conditions are satisfied:

• A priority value associated with the received SL resource reservation may be lower than a (pre)configured threshold, i e. the priority of the SL transmission may be higher than that denoted by the threshold;

• A CAPC configuration associated with the resource reservation may be lower than a (pre)configured threshold, i.e. the channel access priority may be higher than that denoted by the threshold;

• The associated transmit power parameter being higher than a (pre)configured threshold. In another option, a UE may not be triggered for reporting transmission when the resource reservation is associated with a very low power mode;

• The associated SL RSRP measurement value being higher than a (pre)configured threshold;

• The DL RSRP measurement value being lower than a (pre)configured threshold;

• The associated SL RSRP measurement value being higher than a (pre)configured threshold and the DL RSRP measurement value being lower than (pre)configured respective thresholds;

• The associated SL RSRP measurement value being higher than the DL RSRP measurement value by a difference higher than a (pre)configured threshold;

• A measured CBR of the resource pool being higher than a (pre)configured threshold; and/or

• The time between the SL resource reservation information and the first overlapping PDCCH and/or flexible monitoring slot being larger than a (pre)configured time threshold for reporting transmission. This is to ensure sufficient time for gNB to receive the reporting and adjust scheduling accordingly.

[0108] In some implementations, a UE may report the received SL resource reservation information in a PUCCH transmission. A UE may be (pre)configured with PUCCH resources in one or more (pre)configured RB set(s). A UE may determine which RB set for a PUCCH transmission based on the RB set indicated in the SL resource reservation information In one example, a UE may perform the PUCCH transmission in the resource (pre)configured in the same RB set.

[0109] The reported SL resource reservation may include an explicit indication of the reserved slots. For example, in some implementations, a UE may use the index of a slot in a SL resource pool to indicate each reserved slot. In another example, the index of the first slot of COT and the duration of the remaining COT duration may be included in the reservation information reporting. The number of reserved slots may be determined based on the slots included in the remaining COT duration.

[01 10] In some implementations, a UE may report the information of the PDCCH monitoring slots overlapping with the slots reserved in SL resource reservation. In one example, a UE may use a bit map corresponding to the PDCCH and flexible monitoring slot (pre)configuration. A UE may indicate a value of one at the bit corresponding to the PDCCH and/or flexible monitoring slot to indicate an overlapping with a SL resource reservation.

[01 11] In some implementations, a UE may indicate an expected PSCCH and PDCCH monitoring conflict to the UE who may transmit the SL resource reservation. A UE may transmit this indication in a PSFCH. A UE may determine the resource of the PSFCH based on a (pre)configured association with the resource of the PSCCH in which the UE has received the SL resource reservation information Thus, a PSFCH transmission in the resource associated with the PSCCH resource may indicate implicitly an expected PSCCH and PDCCH monitoring conflict caused by one or more slots reserved in the resource reservation information carried in the PSCCH. In another example, a UE may indicate which reserved slots may have the conflict in the PSFCH. A PSFCH bit field may include a number of bits with each bit corresponding to a reserved slot and a value of one may be used to indicate a conflict in the reserved slot.

[01 12] In some implementations, when a UE has performed the reporting transmission, a UE may skip PDCCH monitoring in the overlapping PDCCH and/or flexible monitoring slot. A UE may monitor PSCCH according to the received SL resource reservation in the overlapping PDCCH and/or flexible monitoring slot A UE may consider the serving gNB upon receiving the reporting transmission may avoid a PDCCH transmission of a DCI format in the overlapping PDCCH and/or flexible monitoring slot.

[01 13] In some implementations, when a UE has performed the reporting transmission, a UE may receive a DCI format in a PDCCH in a PDCCH and/or flexible monitoring slot preceding the overlapping PDCCH and/or flexible monitoring slot. A UE may be indicated in the DCI format to prioritize PDCCH monitoring in the overlapping slot In this case, the serving gNB upon receiving the reporting transmission may determine to transmit PDCCH in the overlapping slot(s) e.g., due to scheduling constraint.

[01 14] In some implementations, a UE may not perform a reporting transmission when the time between the SL resource reservation information and the first overlapping PDCCH and/or flexible monitoring slot is not larger than a (pre)configured time threshold for reporting transmission. In this case, a UE skip PDCCH monitoring in the overlapping PDCCH and/or flexible monitoring slot. [01 15] In some implementations, when a UE has performed a SL indication transmission in a PSFCH, a UE may perform PSCCH monitoring in the overlapping PDCCH and/or flexible monitoring slots.

[01 16] FIG. 3 is a flow chart of an implementation of a method 300 for sidelink resource management.

[01 17] At 302, an SL UE is configured with sidelink resource pool that has multiple RB sets in frequency domain. Some sidelink slots can be used either by Uu (e.g., PDCCH transmission) or sidelink transmissions.

[01 18] At 304, the sidelink UE is configured with CORESET/search space monitoring within the flexible slots that can be used by Uu and sidelink transmissions PDCCH monitoring occasion can collide with

PSSCH/PSCCH monitoring.

[01 19] At 306, the SL UE is pre-configured with one or more of the following criteria to report a detected sidelink resource reservation to the gNB:

• High priority sidelink resource reservation;

• The reserved sidelink resource are overlapping with a pre-configured slots indicated by the gNB. The SL UE is pre-configured with slots to report if sidelink resource reservation is transmitted e.g , the reserved sidelink resources are overlapping with PDCCH resources; and/or

• Measured RSRP from the UE transmitting sidelink resource reservation is below a configured threshold.

[0120] Upon detecting SCI reserving sidelink resource and satisfies the pre-configured criteria at 308, the SL UE determines if the triggers have been satisfied at 310, and if so, at 312 the SL UE reports to the gNB the reserved resources using an uplink control transmission. The SL UE is configured with PUCCH resources in multiple RB set(s) to report the sidelink resource reservation to the gNB. The SL UE uses a PUCCH resource (in the same RB set or a different RB set from the RB set(s) reserved by sidelink UEs). The SL UE determines the PUCCH resource to use based on the reserved RB set.

[0121] Accordingly, the present disclosure is also directed to systems and methods for sidelink resource selection and management, particularly for shared Uu and sidelink resources. In one aspect, a device such as user equipment (UE) is configured to monitor sidelink resource reservations transmitted by other sidelink UEs. Upon detecting a resource reservation in a sidelink channel which satisfies a pre-configured criteria, the UE may indicate the resource reservation to the gNB using uplink control information and adjust PDCCH monitoring accordingly

[0122] In some implementations, such methods include monitoring, by a user equipment (UE) device, a communication channel with one or more additional UEs, the communication channel shared for Uu transmissions and sidelink transmissions. The methods also include detecting, by the UE, a transmission from another UE of the one or more additional UEs, via the communication channel. The methods also include determining, by the UE, that a condition of the communication channel satisfies a sidelink resource reservation trigger. The methods also include, responsive to detecting the transmission from the another UE and the condition of the communication channel satisfying the sidelink resource reservation trigger, transmitting, by the UE to a base station, data comprising a sidelink resource reservation.

[0123] In some implementations, the transmission from the another UE comprises a physical sidelink control channel (PSCCH) transmission. In a further implementation, the PSCCH transmission comprises a sidelink control information (SCI) data field. In some implementations, monitoring the communication channel comprises monitoring one or both of a physical sidelink control channel (PSCCH) slot and a physical downlink control channel (PDCCH) slot. In some implementations, determining that the condition of the communication channel satisfies the sidelink resource reservation trigger comprises determining that a priority value identified in the transmission from the another UE exceeds a threshold associated with the communication channel. In some implementations, determining that the condition of the communication channel satisfies the sidelink resource reservation trigger comprises determining that a transmission power of the transmission from the another UE exceeds a threshold associated with the communication channel. In some implementations, determining that the condition of the communication channel satisfies the sidelink resource reservation trigger comprises determining that a reference signal received power (RSRP) from the another UE exceeds a threshold associated with the communication channel In some implementations, determining that the condition of the communication channel satisfies the sidelink resource reservation trigger comprises determining that a reference signal received power (RSRP) from the base station is lower than a threshold associated with the communication channel. In some implementations, determining that the condition of the communication channel satisfies the sidelink resource reservation trigger comprises determining that a channel busy ratio (CBR) of the communication channel exceeds a threshold. In some implementations, determining that the condition of the communication channel satisfies the sidelink resource reservation trigger comprises determining that a time between a sidelink reservation time identified in the transmission from the another UE and a subsequent monitoring time exceeds a threshold.

[0124] In still another aspect, the present disclosure is directed to systems and methods for sidelink resource selection and management, particularly for shared Uu and sidelink resources. A sidelink UE is configured to monitor two types of gNB reservations in the sidelink resources: a first type prohibits the UE from transmitting on the sidelink, and a second type restricts the transmission power in the reserved resources.

[0125] In brief overview, in some implementations, a Sidelink UE may be configured with autonomous resource selection to transmit on sidelink channel. The sidelink UE may also be configured to monitor sidelink resource reservations transmitted by other sidelink UEs indicating gNB reservation. There may be two (or more) possible types of gNB reservation on sidelink resources: a first type of reservation prohibits the sidelink UE from transmitting on the reserved resource, and a second type of reservation restrict the transmission power on sidelink resource (e.g., very low power transmission). For the latter case, the UE may be configured with a maximum power transmission (i.e., very low power level) to use on such resources.

[0126] The sidelink UE may monitor the channel during a sensing or monitoring window to determine candidate resources for selection/re-selection If the sidelink UE starts the resource selection procedure, in some implementations, the UE may exclude any resource reserved with the first type of gNB reservation; and the UE may include as candidates (or not exclude) resources reserved with the second type of gNB reservation (but in some implementations may consider those resources with low priority for selection. If the sidelink UE selects a resource reserved with the second type of gNB reservation, the sidelink UE may transmit with very low power in some implementations (e.g. 50%, 20%, 10%, 1 % or any other such power level relative to normal transmission power levels).

[0127] If the sidelink UE has selected a sidelink resource from the candidate resources and receives an indication of gNB reservation on the selected resources, then in some implementations:

• The UE stops transmitting on the resource if the resource reservation indicates the first type of gNB reservation; or

• The UE reduces the transmission power to low power on the resource if the resource reservation indicates the second type of gNB reservation and based on the RSRP from the gNB/Mode 1 UE transmitting a gNB resource reservation. If RSRP from the gNB or Mode 1 UE is below a first threshold, the sidelink UE may transmit with full power If RSRP from the gNB or Mode 1 UE is below a second threshold and above the first threshold, the sidelink UE transmits with low power. If RSRP from the gNB or Mode 1 UE is below a third threshold and above the second threshold, the sidelink UE does not transmit.

[0128] In more detail, in some implementations, a UE (e.g., Mode 1 UE) may perform one or more sidelink transmissions to indicate to other UEs of a gNB reservation of a shared resource. The reserved resource may be used by the gNB for scheduling Uu transmission/reception or it also can be used by the gNB to schedule transmissions by the Mode 1 UE. The UE may indicate the gNB reservation in a sidelink control information (SCI) field in a sidelink transmission (e.g., first stage SCI and/or second stage SCI) to other UEs The SCI may implicitly or explicitly indicate the resource is for gNB reservation, depending on implementation. In some implementations, the UE may further indicate (e g., in SCI) one or any combination of the following types of resource reservation (e.g., gNB reservation):

• A first type of reservation prohibits sidelink UEs from transmitting on the reserved resource. For example, for this type of resource reservation, the UE may request another UE (e.g., Mode 2 UE) not to use the reserved resource. In some implementations, the another UE, upon detecting the first type of reservation, may not use the reserved resource for its transmission. Specifically, the another UE may exclude the reserved resource from the set of candidate resources for resource selection. In another implementation, the another UE may be configured with a RSRP threshold for the first type of reserved resource. The RSRP threshold may be configured based on a transmission priority (e g. with a plurality of thresholds corresponding to a plurality of priorities). The another UE, upon detecting the first type of reservation, may exclude the reserved resource from the set of candidate resources if the measured RSRP of the reserving signal is greater than the configured RSRP threshold. Otherwise, if the measured RSRP is greater than the configured RSRP threshold, the UE may not exclude the reserved resource from the set of candidate resources (or may include the reserved resources in the set of candidate resources); • A second type of reservation restricts the transmission power on the sidelink resource (e.g., very low power transmission). For example, for this type of resource reservation, the UE may request another UE (e.g., Mode 2 UE) to use very low power transmissions on the reserved resource (e.g. 50%, 25%, 10%, 5%, 1 %, or any other such value relative to a normal power transmission). Specifically, the another UE may be configured with a maximum transmission power (e.g., very low power level) to use the resource reserved by the second type of reservation. In some implementations, during a resource selection procedure, the another UE may not exclude the resource reserved by the second type of resource regardless of the measured RSRP of the reserving signal. In another implementation, the UE may be configured with another RSRP threshold for the second type of reserved resource. The UE may exclude the reserved resource if the measured RSRP is greater than the configured threshold.

[0129] The type of reservation may be indicated via a flag, string, predetermined bit, value in an options field, type value, or any other type and form of indicator within the resource reservation or SCI. For example, a flag may be set to a first value (e.g. 0) to indicate the first type of reservation and a second value (e.g. 1) to indicate the second type of reservation.

[0130] In some implementations, a UE (e.g., Mode 2 UE) may perform sensing to detect the potential resource reservation (e.g., gNB reservation). The UE may detect the first type and/or the second type of reservation (e.g., gNB reservation), which may be transmitted by another UE (e.g., Mode 1 UE). The type of reservation may be indicated in the SCI of a transmission. In one approach, the UE may determine whether to exclude a reserved resource based on the type of reservation regardless of measured RSRP. Specifically, if the UE detect the first type of reservation, the UE may exclude the reserved resource from the set of candidate resources. If the UE detects the second type of reservation, the UE may not exclude the reserved resource from the set of candidate resources. In another approach, the UE may determine whether to exclude a reserved resource based on the type of reservation considering measured RSRP. Specifically, the UE may be configured with two RSRP thresholds, in which the first RSRP threshold may be associated with the first type of reservation and the second RSRP threshold may be associated with the second type of reservation. The UE may exclude (e g., from the set of candidate resources) a resource reserved by the first type of reservation if the measured RSRP is greater than the first RSRP threshold. The UE may exclude (e.g , from the set of candidate resources) a resource reserved by the second type of reservation if the measured RSRP is greater than the second RSRP threshold.

[0131] In some implementations, the UE may select one or more resources from the set of candidate resources to perform transmission. The UE may perform a listen-before-talk (LBT) protocol on one or more selected resources. The UE may then determine the transmission power on the selected resource based on the type of the selected resource. Specifically, the UE may be configured with two (or more) maximum transmission power values, with a first value (e.g., a very low maximum transmission power) associated with the transmission in a resource reserved by the second type of reservation, and the second value (e.g., a normal maximum transmission power) associated with a resource not reserved by a second type of reservation. As used herein, “very low” and “normal” should be considered relative terms, such that the very low maximum transmission power is a fraction of the normal maximum transmission power (e.g. 50%, 25%, 10%, 5%, 1 %, or any other such value). If the UE selects a resource reserved by a second type of reservation, the UE may determine the transmission power to be smaller or equal then or equal to the first maximum transmission power. Alternatively, if the selected resource is not reserved by the second type of reservation, the UE may determine the transmission power to be smaller than or equal to the second maximum transmission power.

[0132] In some implementations, the UE may perform pre-emption checking to determine the availability of its selected and/or reserved resource before transmitting in the resource. The UE may detect a first type of reservation overlapping with its selected/reserved resource. The UE may stop transmitting in the selected/reserved resource regardless of the measured RSRP. The UE may reselect another resource to for transmission.

[0133] In some implementations, the UE may detect a second type of reservation (e.g., gNB reservation transmitted by Mode 1 UE) overlapping with its selected/reserved resource. The UE may then determine whether to stop transmission in the selected/reserved resource based on the measured RSRP of the reserving signal. Specifically, if the measured RSRP of the second type of reservation (e.g., gNB reservation transmitted by a UE), is greater than a configured threshold (e.g., the first RSRP threshold), the UE may stop its transmission in the selected/reserved resource. Otherwise, in some implementations, the UE may continue to transmit in the selected/reserved resource. In case the UE determines to continue transmitting in the selected/reserved resource, the UE may determine the transmission power on the resource based on the measured RSRP of the reserving signal. Specifically, the UE may determine to transmit in the selected resource using the first configured transmission power (e.g., full transmission power) if the measured RSRP of the reserving signal is smaller than another configured threshold (e.g., the second RSRP threshold). Otherwise, if the measured RSRP of the reserving signal is greater than the second configured threshold and greater than the first configured threshold, the UE may determine to transmit in the selected resource using the second configured transmission power (e.g., low transmission power).

[0134] FIG. 4 is a flow chart of an implementation of a method 400 for sidelink resource management.

[0135] At 402, a sidelink UE, such as a Mode 2 UE, may be configured with autonomous resource selection to transmit on sidelink channel. At 404, the sidelink UE is configured to monitor a channel for sidelink resource reservations transmitted by other sidelink UEs indicating gNB reservation. gNB reservations on sidelink resources may include a first type of reservation, receipt of which prohibits the sidelink UE from transmitting on the reserved resource; or a second type of reservation that restricts the UE’s transmission power on the sidelink resource (e g., restricting to very low power transmissions). The UE may be configured with a maximum power transmission level (i.e., very low power level) to use in such instances

[0136] At 406, the sidelink UE may monitor or sense the channel during a monitoring or sensing window to determine or select candidate resources for selection/re-selection . For example, the sidelink UE may perform measurements on the channel or channels for signal strength, noise, congestion, bandwidth, interference, or any other type and form of characteristic or attributes of the channel or resource.

[0137] To determine whether a resource should be included as a candidate for selection, the UE excludes any resource reserved with first type of gNB reservation at 412; and does not exclude resources reserved with second type of gNB reservation at 414 but considers those resource to have low priority for selection. If the sidelink UE selects a resource reserved with second type of gNB reservation (e.g. the reservation is not the first type of reservation at 410), then at 414 the sidelink UE transmits with very low power.

[0138] In some implementations, once a sidelink resource has been selected, if the UE receives an indication of gNB reservation on the selected resource at 408, then if the reservation indicates the first type of reservation at 410, then at 412 the UE stops transmitting on the resource. Otherwise, if the resource reservation indicates the second type of reservation at 410, then at 414 the UE reduces the transmission power to low power on the resource. In some implementations, this may further be responsive to an RSRP from the gNB or Mode 1 UE transmitting a gNB resource reservation. In such implementations, If the RSRP is below a first threshold, the sidelink UE transmits with full power; if the RSRP is below a second threshold and above the first threshold, the sidelink UE transmits with low power; and if the RSRP is below a third threshold and above the second threshold, the sidelink UE does not transmit.

[0139] Accordingly, the present disclosure also describes systems and methods for sidelink resource selection and management, particularly for shared Uu and sidelink resources. A sidelink UE is configured to monitor two types of gNB reservations in the sidelink resources: a first type prohibits the UE from transmitting on the sidelink, and a second type restricts the transmission power in the reserved resources.

[0140] In some implementations, such methods include monitoring, by a user equipment (UE) device, a communication channel utilized by a base station and one or more additional UEs, the communication channel comprising a plurality of resources shared for Uu transmissions and sidelink transmissions. The methods also include detecting, by the UE, a transmission from the base station or another UE of the one or more additional UEs, via the communication channel, the transmission indicating a resource reservation by the base station. The methods also include determining, by the UE, whether the resource reservation indicates that (i) the UE should not utilize the reserved resource, or (ii) the UE may utilize the reserved resource at a reduced power level relative to a normal transmission power level. The methods also include, responsive to the determination, respectively either (i) preventing transmission via the reserved resource for a predetermined time period, or (ii) transmitting data via the reserved resource at the reduced power level.

[0141] In some implementations, the transmission from the base station or another UE comprises a physical sidelink control channel (PSCCH) transmission In a further implementation, the PSCCH transmission comprises a sidelink control information (SCI) data field. In some implementations, monitoring the communication channel comprises monitoring one or both of a physical sidelink control channel (PSCCH) slot and a physical downlink control channel (PDCCH) slot. In some implementations, the resource reservation comprises a flag set to a first value indicating indicates that the UE should not utilize the reserved resource, or a second value indicating that the UE may utilize the reserved resource at a reduced power level relative to a normal transmission power level. In some implementations, the resource reservation indicates that the UE should not utilize the reserved resource, and further comprising excluding, by the UE, the reserved resource from a set of one or more candidate resources for transmitting data In some implementations, the resource reservation indicates that the UE may utilize the reserved resource, and further comprising reducing, by the UE, a priority of the reserved resource in a set of one or more candidate resources for transmitting data, each candidate resource having a corresponding priority In some implementations, the resource reservation indicates that the UE may utilize the reserved resource, and further comprising measuring, by the UE, a reference signal received power (RSRP) from the base station or the another UE. In a further implementation, the method includes transmitting data via the reserved resource at the normal power level, responsive to the measured RSRP being below a first threshold. In another further implementation, transmitting data via the reserved resource at the reduced power level is further responsive to the measured RSRP being above a first threshold and below a second threshold. In still another further implementation, the method includes preventing transmission of data via the reserved resource, responsive to the measured RSRP being above each of a first threshold and a second threshold, and below a third threshold.

[0142] 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, magnetooptical 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, comprising: monitoring, by a user equipment (UE) device, a communication channel with a base station, the communication channel shared for Uu transmissions and sidelink transmissions; determining, by the UE, that a condition of the communication channel satisfies a sidelink resource reservation trigger; detecting, by the UE, a transmission from the base station via the communication channel; and responsive to detecting the transmission from the base station and the condition of the communication channel satisfying the sidelink resource reservation trigger, transmitting, by the UE to one or more additional UEs, data comprising a sidelink resource reservation.

2. The method of claim 1 , wherein the transmission from the base station comprises a physical downlink control channel (PDCCH) transmission.

3. The method of claim 1 , wherein the transmission from the base station comprises an identification of a first one or more slots to be utilized for Uu transmission of a plurality of slots of the communication channel.

4. The method of claim 3, wherein the sidelink resource reservation identifies the first one or more slots.

5. The method of any preceding claim, wherein determining that the condition of the communication channel satisfies the sidelink resource reservation trigger comprises detecting a resource reservation transmitted by the base station comprising a sidelink control information (SCI) resource.

6. The method of any preceding claim, wherein determining that the condition of the communication channel satisfies the sidelink resource reservation trigger comprises determining that a measured reference signal received power (RSRP) from the base station is below a threshold.

7. The method of any preceding claim, wherein determining that the condition of the communication channel satisfies the sidelink resource reservation trigger comprises detecting a transmission by the base station indicating that a side link resource reservation is activated.

8 The method of any preceding claim, wherein determining that the condition of the communication channel satisfies the sidelink resource reservation trigger comprises determining that a scheduled transmission time of the UE is occurring.

9. The method of any preceding claim, wherein determining that the condition of the communication channel satisfies the sidelink resource reservation trigger comprises detecting transmissions via the communication channel from the one or more additional UEs.

10. A wireless transmit/receive unit (WTRU), comprising: one or more transceivers; and one or more processors; wherein the one or more processors are configured to: monitor, via the one or more transceivers, a communication channel with a base station, the communication channel shared for Uu transmissions and sidelink transmissions, determine that a condition of the communication channel satisfies a sidelink resource reservation trigger, detect a transmission from the base station via the communication channel, and responsive to detecting the transmission from the base station and the condition of the communication channel satisfying the sidelink resource reservation trigger, transmit, via the one or more transceivers to one or more additional UEs, data comprising a sidelink resource reservation.

11. The WTRU of claim 10, wherein the transmission from the base station comprises a physical downlink control channel (PDCCH) transmission.

12. The WTRU of claim 10, wherein the transmission from the base station comprises an identification of a first one or more slots to be utilized for Uu transmission of a plurality of slots of the communication channel.

13. The WTRU of claim 12, wherein the sidelink resource reservation identifies the first one or more slots.

14. The WTRU of any of claims 10-13, wherein determining that the condition of the communication channel satisfies the sidelink resource reservation trigger comprises detecting a resource reservation transmitted by the base station comprising a sidelink control information (SCI) resource.

15. The WTRU of any of claims 10-14, wherein determining that the condition of the communication channel satisfies the sidelink resource reservation trigger comprises determining that a measured reference signal received power (RSRP) from the base station is below a threshold.

16. The WTRU of any of claims 10-15, wherein determining that the condition of the communication channel satisfies the sidelink resource reservation trigger comprises detecting a transmission by the base station indicating that a side link resource reservation is activated.

17. The WTRU of any of claims 10-16, wherein determining that the condition of the communication channel satisfies the sidelink resource reservation trigger comprises determining that a scheduled transmission time of the UE is occurring.

18. The WTRU of any of claims 10-17, wherein determining that the condition of the communication channel satisfies the sidelink resource reservation trigger comprises detecting transmissions via the communication channel from the one or more additional UEs.

19. A non-transitory computer readable medium comprising instructions that, when executed by one or more processors of a device, cause the device to perform operations comprising: monitoring, via one or more transceivers of the device, a communication channel with a base station, the communication channel shared for Uu transmissions and sidelink transmissions; determining that a condition of the communication channel satisfies a sidelink resource reservation trigger; detecting a transmission from the base station via the communication channel, and responsive to detecting the transmission from the base station and the condition of the communication channel satisfying the sidelink resource reservation trigger, transmitting, via the one or more transceivers to one or more additional UEs, data comprising a sidelink resource reservation.

20. The computer readable medium of claim 19, wherein the transmission from the base station comprises a physical downlink control channel (PDCCH) transmission or an identification of a first one or more slots to be utilized for Uu transmission of a plurality of slots of the communication channel.