Apparatus and method for new radio sidelink channel state information acquisition

Abstract

A method for use in a wireless transmit / receive unit (WTRU) is disclosed. The WTRU is capable of communicating with a network over a sidelink (SL). The WTRU is configured with a scheduling request (SR) configuration set. The method comprises: receiving (1) a CSI report request requesting a CSI report and (2) CSI report delay information of the CSI report through the SL; starting a timer based on the received CSI report delay information; triggering an SR transmission specific to the CSI report; and determining whether an SL grant has been received prior to expiration of the timer, where the method further comprises, on condition that the SL grant has been received prior to expiration of the timer, 205 transmitting a CSI report based on the SL grant; if the SL grant is not received prior to expiration of the timer, the method further comprises 206 discarding the CSI report.

Description

[0001] This application is a divisional application of the Chinese invention patent application with the application date of August 13, 2020, application number 202080064730.1, and invention name “Device and method for acquiring new radio side link channel state information”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims the benefit of U.S. Provisional Application No. 62 / 886,740 filed on August 14, 2019, U.S. Provisional Application No. 62 / 930,970 filed on November 5, 2019, and U.S. Provisional Application No. 62 / 975,497 filed on February 12, 2020, the contents of which are incorporated herein by reference. Background Art

[0004] A vehicle-to-everything (V2X) communication architecture has been developed for wireless communication systems, including those using an evolved packet core (EPC). V2X communications may include one or more of vehicle-to-vehicle (V2V) communications, vehicle-to-pedestrian (V2P) communications, vehicle-to-infrastructure (V2I) communications, and vehicle-to-network (V2N) communications.

[0005] New Radio (NR) V2X may support two modes of operation, Mode 1 and Mode 2. Mode 1 is based on Long Term Evolution (LTE) V2X Mode 3 operation. For example, the network may schedule sidelink (SL) resources via downlink (DL) downlink control information (DCI) signaling, and the wireless transmit / receive unit (WTRU) may apply the received resource reservation to the SL transmission. Mode 2 may use LTE Mode 4 as a baseline for semi-persistent scheduling. In Mode 4, the WTRU may autonomously select and reserve resources from a configured resource pool. In one example, the configured resource pool may be a pre-configured resource pool. Autonomous resource reservation may be based on WTRU sensing to identify available candidate resources. Summary of the invention

[0006] The present invention discloses a method used in a wireless transmit / receive unit (WTRU). The WTRU is capable of communicating with a network via a side link (SL). The WTRU is configured with a scheduling request (SR) configuration set. The method includes: receiving (1) a CSI report request for requesting a CSI report and (2) CSI report delay information for the CSI report via the SL; starting a timer based on the received CSI report delay information; triggering SR transmission specific to the CSI report; and determining whether an SL authorization has been received before the timer expires, wherein under the condition that the SL authorization has been received before the timer expires, the method further includes 205 transmitting the CSI report based on the SL authorization; under the condition that the SL authorization has not been received before the timer expires, the method further includes 206 discarding the CSI report.

[0007] The present invention discloses a wireless transmit / receive unit (WTRU). The WTRU is capable of communicating with a network via a side link (SL), and the WTRU is configured with a scheduling request (SR) configuration set. The WTRU includes: a transceiver configured to receive (1) a CSI report request for requesting a CSI report and (2) CSI report delay information of the CSI report via the SL; a processor configured to: start a timer based on the received CSI report delay information; and trigger SR transmission specific to the CSI report; determine whether an SL authorization has been received before the timer expires, wherein under the condition that the SL authorization has been received before the timer expires, the processor is further configured to transmit the CSI report through the transceiver based on the SL authorization; and under the condition that the SL authorization has not been received before the timer expires, the processor is further configured to discard the CSI report. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0009] Figure 1A is a system diagram illustrating an exemplary communication system in which one or more disclosed embodiments may be implemented;

[0010] Figure 1B It is shown that according to one embodiment, Figure 1A A system diagram of an exemplary wireless transmit / receive unit (WTRU) for use within the communication system shown;

[0011] Figure 1C It is shown that according to one embodiment, Figure 1A A system diagram of an exemplary radio access network (RAN) and an exemplary core network (CN) used within the illustrated communication system;

[0012] Figure 1D It is shown that according to one embodiment, Figure 1A A system diagram of another exemplary RAN and another exemplary CN used in the communication system shown;

[0013] Figure 2 is a flow chart illustrating a method according to an embodiment of the present disclosure;

[0014] Figure 3 is a timing diagram illustrating an example of a channel state information (CSI) reporting time window;

[0015] Figure 4 is a timing diagram showing an example of multiplexing multiple CSI reports; and

[0016] Figure 5 is a timing diagram showing an example of multiplexing CSI reporting with CSI reporting indexes. DETAILED DESCRIPTION

[0017] Figure 1A 1 is a schematic diagram illustrating an exemplary communication system 100 in which one or more disclosed embodiments may be implemented. The communication system 100 may be a multiple access system that provides content such as voice, data, video, messaging, broadcast, etc. to multiple wireless users. The communication system 100 may enable multiple wireless users to access such content through sharing of system resources (including wireless bandwidth). For example, the communication system 100 may employ one or more channel access methods such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single carrier FDMA (SC-FDMA), zero tail unique word discrete Fourier transform spread OFDM (ZT-UW-DFT-S-OFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, filter bank multi-carrier (FBMC), etc.

[0018] like Figure 1AAs shown, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, a radio access network (RAN) 104, a core network (CN) 106, a public switched telephone network (PSTN) 108, the Internet 110 and other networks 112, but it should be understood 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 user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a cellular phone, a personal digital assistant (PDA), a smart phone, a laptop, a netbook, a personal computer, a wireless sensor, a hotspot or Mi-Fi device, an Internet of Things (IoT) device, a watch or other wearable device, a head-mounted display (HMD), a vehicle, a drone, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in an industrial and / or automated process chain environment), a consumer electronic device, a device operating on a commercial and / or industrial wireless network, etc. Any of the WTRUs 102a, 102b, 102c, and 102d may be interchangeably referred to as a UE.

[0019] The communication system 100 may also include a base station 114a and / or a base station 114b. Each of the base stations 114a, 114b may be any type of device that is 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 other networks 112. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a NodeB, an evolved NodeB (eNB), a Home NodeB, a Home evolved NodeB, a next generation NodeB such as a gNodeB (gNB), a new radio (NR) NodeB, a site controller, an access point (AP), a wireless router, and the like. Although the base stations 114a, 114b are each depicted as a single element, it should be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0020] 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), a relay node, etc. The base station 114a and / or the base station 114b may be configured to transmit and / or receive wireless signals on one or more carrier frequencies, which may be referred to as a cell (not shown). These frequencies may be in a licensed spectrum, an unlicensed spectrum, or a combination of licensed and unlicensed spectrums. A cell may provide coverage of wireless services to a specific geographic area, which may be relatively fixed or may change over time. The cell may be further divided into cell sectors. For example, a cell associated with the base station 114a may be divided into three sectors. Therefore, in one embodiment, the base station 114a may include three transceivers, i.e., one transceiver for each sector of the cell. In one embodiment, the base station 114a may employ multiple-input multiple-output (MIMO) technology and may utilize multiple transceivers for each sector of the cell. For example, beamforming may be used to transmit and / or receive signals in a desired spatial direction.

[0021] 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).

[0022] More specifically, as noted above, the communication 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, etc. 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 use Wideband CDMA (WCDMA) to establish the air interface 116. 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).

[0023] In one embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface 116 using Long Term Evolution (LTE) and / or Advanced LTE (LTE-A) and / or Advanced LTE Pro (LTE-APro).

[0024] In one embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR radio access, which may establish the air interface 116 using NR.

[0025] In one embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may implement LTE radio access and NR radio access together, for example using dual connectivity (DC) principles. Thus, the air interface utilized by the WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions sent to / from multiple types of base stations (e.g., eNBs and gNBs).

[0026] 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, CDMA2000EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile Communications (GSM), GSM Enhanced Data Rates for Evolution (EDGE), GSM EDGE (GERAN), etc.

[0027] Figure 1AThe base station 114b in the may be, for example, a wireless router, a Home NodeB, a Home eNodeB, or an access point, and may utilize any suitable RAT to facilitate wireless connectivity in a local area, such as a business location, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a road, 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 one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish a picocell or a femtocell. As Figure 1A As shown, the base station 114 b may have a direct connection to the Internet 110. Therefore, the base station 114 b may not need to access the Internet 110 via the CN 106.

[0028] 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 different quality of service (QoS) requirements, such as different throughput requirements, delay requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. 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 described in detail in the specification, the CN 106 may be 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. Figure 1A Although not shown in the figure, 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 utilize NR radio technology, the CN 106 may also be in communication with another RAN (not shown) that employs GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.

[0029] The CN 106 may also act as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and / or other networks 112. The PSTN 108 may include a circuit-switched telephone network that provides 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), the 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 communication 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.

[0030] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communication 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 via different wireless links). Figure 1A The illustrated WTRU 102c may be configured to communicate with the base station 114a, which may employ a cellular-based radio technology, and with the base station 114b, which may employ an IEEE 802 radio technology.

[0031] Figure 1B is a system diagram illustrating an exemplary WTRU 102. Figure 1B As shown, the WTRU 102 may include, among other things, a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and / or other peripherals 138. It will be appreciated that the WTRU 102 may include any subcombination of the foregoing elements while remaining consistent with an embodiment.

[0032] 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 associated with a DSP core, a controller, a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), any other type of integrated circuit (IC), a state machine, etc. The processor 118 may perform signal coding, data processing, power control, input / output processing, and / or any other functions that enable the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit / receive element 122. Although Figure 1B The processor 118 and the transceiver 120 are depicted as separate components, but it is understood that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0033] The transmit / receive element 122 may be configured to transmit signals to or receive signals from a base station (e.g., base station 114a) via an air interface 116. For example, in one embodiment, the transmit / receive element 122 may be an antenna configured to transmit and / or receive RF signals. In one embodiment, the transmit / receive element 122 may be a transmitter / detector configured to transmit and / or receive, for example, IR, UV, or visible light signals. In yet another embodiment, the transmit / receive element 122 may be configured to transmit and / or receive RF and light signals. It should be appreciated that the transmit / receive element 122 may be configured to transmit and / or receive any combination of wireless signals.

[0034] Although the transmit / receive element 122 is Figure 1B 1 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.

[0035] The transceiver 120 may be configured to modulate signals to be transmitted by the transmit / receive element 122 and to demodulate signals received by the transmit / receive element 122. As noted above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11.

[0036] The processor 118 of the WTRU 102 may be coupled to a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light emitting diode (OLED) display unit) and may receive user input data therefrom. 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 a non-removable memory 130 and / or a removable memory 132. The non-removable memory 130 may include a random access memory (RAM), a 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 a memory that is not physically located on the WTRU 102, such as on a server or a home computer (not shown).

[0037] The processor 118 may receive power from the power source 134, and may be configured to distribute and / or control power to 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, etc.

[0038] 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 from a base station (e.g., base stations 114a, 114b) over the air interface 116 and / or determine its location based on the timing of signals received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information by any suitable location-determination method while remaining consistent with an embodiment.

[0039] The processor 118 may also be coupled to other peripherals 138, which may include one or more software modules and / or hardware modules that provide additional features, functionality, and / or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an electronic compass, a satellite transceiver, a digital camera (for photos and / or video), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands-free headset, Module, FM radio unit, digital music player, media player, video game player module, Internet browser, virtual reality and / or augmented reality (VR / AR) device, activity tracker, etc. Peripheral device 138 may include one or more sensors. The sensor may be one or more of the following: gyroscope, accelerometer, Hall effect sensor, magnetometer, orientation sensor, proximity sensor, temperature sensor, time sensor; geographic location sensor, altimeter, light sensor, touch sensor, magnetometer, barometer, gesture sensor, biometric sensor, humidity sensor, etc.

[0040] The WTRU 102 may include a full-duplex radio for which transmission and reception of some or all signals (e.g., associated with specific subframes for 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 for reducing and / or substantially eliminating self-interference via hardware (e.g., a choke) or via signal processing performed by a processor (e.g., a separate processor (not shown) or via the processor 118). In one embodiment, the WTRU 102 may include a half-duplex radio for which transmission and reception of some or all signals (e.g., associated with specific subframes for UL (e.g., for transmission) or DL ​​(e.g., for reception)) may be concurrent and / or simultaneous.

[0041] Figure 1C 1 is a system diagram illustrating the RAN 104 and the CN 106 according to one embodiment. As described 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.

[0042] The RAN 104 may include evolved Node-Bs 160a, 160b, 160c, though it will be appreciated that the RAN 104 may include any number of evolved Node-Bs while remaining consistent with an embodiment. The evolved Node-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 evolved Node-Bs 160a, 160b, 160c may implement MIMO technology. Thus, the evolved Node-B 160a, for example, may use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a.

[0043] Each of the evolved Node Bs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and / or DL, etc. Figure 1C As shown, the eNode-Bs 160a, 160b, 160c may communicate with one another via an X2 interface.

[0044] Figure 1C The illustrated CN 106 may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (PGW) 166. Although the foregoing elements are depicted as part of the CN 106, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0045] The MME 162 may be connected to each of the evolved Node-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, etc. The MME 162 may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as GSM and / or WCDMA.

[0046] The SGW 164 may be connected to each of the evolved Node-Bs 160a, 160b, 160c in the RAN 104 via an 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 the user plane during inter-evolved Node-B handovers, triggering paging when DL data is available for the WTRUs 102a, 102b, 102c, managing and storing the context of the WTRUs 102a, 102b, 102c, and the like.

[0047] 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.

[0048] 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 be in communication 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 other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0049] Although the WTRU Figures 1A to 1D Although described as a wireless terminal, it is contemplated that in certain representative embodiments, such a terminal may (eg, temporarily or permanently) use a wired communications interface with a communications network.

[0050] In a representative embodiment, the other network 112 may be a WLAN.

[0051] A WLAN in infrastructure basic service set (BSS) mode may have an access point (AP) for a 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 to and / or carries traffic away from the BSS. Traffic originating from outside the BSS and leading to the STA may be reached by the AP and may be delivered to the STA. Traffic originating from the STA and leading to a destination outside the BSS may be sent to the AP to be delivered to the corresponding destination. Traffic between STAs within the BSS may be sent by the AP, for example, wherein the source STA may send traffic to the AP, and the AP may deliver traffic to the destination STA. Traffic between STAs within the BSS may be considered and / or referred to as point-to-point traffic. Point-to-point traffic may be sent between the source and destination STAs (e.g., directly between them) using a direct link setup (DLS). In certain representative embodiments, the DLS may use 802.11e DLS or 802.11z tunnel DLS (TDLS). A WLAN using an independent BSS (IBSS) mode may not have an AP, and STAs (eg, all STAs) within or using the IBSS may communicate directly with each other. The IBSS communication mode may sometimes be referred to herein as an "ad-hoc" communication mode.

[0052] When using the 802.11ac infrastructure operating mode or a similar operating mode, 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., a 20 MHz wide bandwidth) or a dynamically set width. The primary channel may be an operating channel of the BSS and may be used by the STA to establish a connection with the AP. In certain representative embodiments, carrier sense multiple access / collision avoidance (CSMA / CA) may be implemented, for example, in an 802.11 system. For CSMA / CA, a STA (e.g., each 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.

[0053] High throughput (HT) STAs may communicate using a 40 MHz wide channel, for example, via a combination of a primary 20 MHz channel and adjacent or non-adjacent 20 MHz channels to form a 40 MHz wide channel.

[0054] Very high throughput (VHT) STA can support 20MHz, 40MHz, 80MHz and / or 160MHz wide channels. 40MHz and / or 80MHz channels can be formed by combining continuous 20MHz channels. A 160MHz channel can be formed by combining 8 continuous 20MHz channels, or by combining two non-continuous 80MHz channels (this can be called 80+80 configuration). For the 80+80 configuration, after channel coding, the data can pass through a segment parser that can divide the data into two streams. Each stream can be processed by inverse fast Fourier transform (IFFT) and time domain processing separately. These streams can be mapped to two 80MHz channels, and data can be transmitted by transmitting STA. At the receiver of the receiving STA, the above-mentioned operation for the 80+80 configuration can be reversed, and the combined data can be sent to the medium access control (MAC).

[0055] 802.11af and 802.11ah support operating modes below 1GHz. Channel operating bandwidths and carriers are reduced in 802.11af and 802.11ah relative to those used in 802.11n and 802.11ac. 802.11af supports 5MHz, 10MHz, and 20MHz bandwidths in the TV White Space (TVWS) spectrum, and 802.11ah supports 1MHz, 2MHz, 4MHz, 8MHz, and 16MHz bandwidths using non-TVWS spectrum. According to a representative embodiment, 802.11ah may support meter type control / machine type communication (MTC), such as MTC devices in macro coverage areas. MTC devices may have certain capabilities, such as limited capabilities, including support for (e.g., only support for) certain bandwidths and / or limited bandwidths. MTC devices may include batteries with battery life above a threshold (e.g., to maintain very long battery life).

[0056] WLAN systems that can support multiple channels and channel bandwidths such as 802.11n, 802.11ac, 802.11af, and 802.11ah include channels that can be designated as primary channels. The primary channel may have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and / or limited by a STA (which supports the minimum bandwidth operating mode) from all STAs operating in the BSS. In the example of 802.11ah, for STAs (e.g., MTC-type devices) that support (e.g., only support) 1MHz mode, the primary channel may be 1MHz wide, even if the AP and other STAs in the BSS support 2MHz, 4MHz, 8MHz, 16MHz, and / or other channel bandwidth operating modes. Carrier sensing and / or network allocation vector (NAV) settings may depend on the state of the primary channel. If the primary channel is busy, for example, because a STA (supporting only the 1MHz operating mode) is transmitting to the AP, all available frequency bands may be considered busy even if most of the available frequency bands remain idle.

[0057] In the United States, the available frequency band for 802.11ah is 902MHz to 928MHz. In South Korea, the available frequency band is 917.5MHz to 923.5MHz. In Japan, the available frequency band is 916.5MHz to 927.5MHz. The total bandwidth available for 802.11ah is 6MHz to 26MHz, depending on the country code.

[0058] Figure 1D 1 is a system diagram illustrating the RAN 104 and the CN 106 according to one embodiment. As noted above, the RAN 104 may employ 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.

[0059] 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 to communicate 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, the gNBs 180a, 180b may utilize beamforming to transmit signals to and / or receive signals from the gNBs 180a, 180b, 180c. Thus, the gNB 180a may, for example, use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a. In one embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation techniques. For example, the gNB 180a may transmit multiple component carriers to the WTRU 102a (not shown). A subset of these component carriers may be on unlicensed spectrum, while the remaining component carriers may be on licensed spectrum. In one embodiment, the gNBs 180a, 180b, 180c may implement coordinated multi-point (CoMP) techniques. For example, the WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and / or gNB 180c).

[0060] The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using transmissions associated with scalable parameter sets. For example, OFDM symbol spacing and / or OFDM subcarrier spacing may vary for different transmissions, different cells, and / or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using subframes or transmission time intervals (TTIs) of varying or scalable lengths (e.g., containing different numbers of OFDM symbols and / or continuously varying absolute time lengths).

[0061] The gNBs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in a standalone configuration and / or a non-standalone configuration. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c while also not accessing other RANs (e.g., such as the eNodeBs 160a, 160b, 160c). In a standalone configuration, the WTRUs 102a, 102b, 102c may use one or more of the gNBs 180a, 180b, 180c as mobility anchor points. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using signals in an unlicensed band. In a non-standalone configuration, the WTRUs 102a, 102b, 102c may communicate or connect with the gNBs 180a, 180b, 180c while also communicating or connecting with other RANs, such as the eNode-Bs 160a, 160b, 160c. For example, the WTRUs 102a, 102b, 102c may implement the DC principle to communicate with one or more gNBs 180a, 180b, 180c and one or more evolved Node-Bs 160a, 160b, 160c substantially simultaneously. In a non-standalone configuration, the evolved Node-Bs 160a, 160b, 160c may serve as mobility anchors for the WTRUs 102a, 102b, 102c, and the gNBs 180a, 180b, 180c may provide additional coverage and / or throughput for serving the WTRUs 102a, 102b, 102c.

[0062] Each of the gNBs 180a, 180b, 180c may be associated with a specific cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in UL and / or DL, support of network slicing, interworking between DC, NR, and E-UTRA, routing of user plane data towards a user plane function (UPF) 184a, 184b, routing of control plane information towards an access and mobility management function (AMF) 182a, 182b, etc. Figure 1D As shown, gNB180a, 180b, and 180c can communicate with each other via the Xn interface.

[0063] Figure 1D The illustrated CN 106 may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one session management function (SMF) 183a, 183b, and possible data networks (DNs) 185a, 185b. Although the aforementioned elements are depicted as part of the CN 106, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0064] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c via the N2 interface in the RAN 104 and may serve as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRU 102a, 102b, 102c, support of network slicing (e.g., handling of different protocol data unit (PDU) sessions with different requirements), selecting a specific SMF 183a, 183b, management of registration areas, termination of non-access stratum (NAS) signaling, mobility management, etc. The AMF 182a, 182b may use network slicing to customize CN support for the WTRU 102a, 102b, 102c based on the type of services used by the WTRU 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 mobile broadband (eMBB) access, services for MTC access, etc. 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.

[0065] The SMF 183a, 183b may be connected to the AMF 182a, 182b in the CN 106 via the N11 interface. The SMF 183a, 183b may also be connected to the UPF 184a, 184b in the CN 106 via the N4 interface. The SMF 183a, 183b may select and control the UPF 184a, 184b, and configure traffic routing through the UPF 184a, 184b. The SMF 183a, 183b may perform other functions such as managing and allocating UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, providing DL data notifications, etc. The PDU session type may be IP-based, non-IP-based, Ethernet-based, etc.

[0066] The UPF 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 104 via the 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, etc.

[0067] 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 other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, 102c may be connected to the DNs 185a, 185b via the UPFs 184a, 184b via the N3 interfaces to the UPFs 184a, 184b and the N6 interfaces between the UPFs 184a, 184b and the local DNs 185a, 185b.

[0068] Given that Figures 1A to 1D as well as Figures 1A to 1D Corresponding to the description of the present invention, one or more or all of the functions described herein with reference to one or more of the following may be performed by one or more simulation devices (not shown): WTRU102a-d, base station 114a-b, evolved Node B 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMF182a-b, UPF184a-b, SMF 183a-b, DN 185a-b and / or any other device described herein. The simulation device may be one or more devices configured to emulate one or more or all of the functions described herein. For example, the simulation device may be used to test other devices and / or simulate network and / or WTRU functions.

[0069] The simulation device may be designed to implement one or more tests of other devices in a laboratory environment and / or in an operator network environment. For example, the one or more simulation devices may perform 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 simulation devices may perform one or more functions or all functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network. The simulation device may be directly coupled to another device for testing purposes and / or perform testing using over-the-air wireless communications.

[0070] The one or more simulation devices may perform one or more (including all) functions without being implemented / deployed as part of a wired and / or wireless communication network. For example, the simulation device may be used in a test scenario in a test lab and / or a non-deployed (e.g., testing) wired and / or wireless communication network to implement testing of one or more components. The one or more simulation devices may be test equipment. Direct RF coupling and / or wireless communication via RF circuits (e.g., which may include one or more antennas) may be used by the simulation device to transmit and / or receive data.

[0071] LTE vehicle-to-everything (V2X) communications may not support channel state information (CSI) acquisition. One reason for this non-support may be that LTE V2X can be applied to broadcast transmissions. NR V2X may support sidelink CSI acquisition for unicast transmissions. In addition, NR CSI acquisition may include at least one of the following features: sidelink CSI reporting can be enabled / disabled by configuration; non-periodic CSI reporting; non-subband based CSI; CSI reference signal (RS) transmission coupled with and limited to physical sidelink shared channel (PSSCH) transmission (i.e., no independent CSI-RS transmission); CSI may include a channel quality indicator (CQI) and a rank indicator (RI) supporting a rank number of up to 2; CQI and RI may be reported together; or, CSI reports may be delivered using PSSCH and its resource allocation process.

[0072] NR V2X can support two operating modes, Mode 1 and Mode 2. Mode 1 is based on Long Term Evolution (LTE) V2X Mode 3 operation. For example, the network may schedule side link (SL) resources via downlink (DL) downlink control information (DCI) signaling, and the WTRU may apply the received resource reservation to the SL transmission. Mode 2 may use LTE Mode 4 as a baseline for semi-persistent scheduling. In Mode 4, the WTRU may autonomously select and reserve resources from a configured resource pool. In one example, the configured resource pool may be a preconfigured resource pool. Autonomous resource reservation may be based on WTRU sensing to identify available candidate resources. The WTRU may schedule resources semi-persistently at a reservation interval. In other words, the WTRU may reserve the same resource once in each reservation interval. In addition, the WTRU may be configured with a resource reselection counter and a trigger condition, and will reselect resources when the counter expires or the trigger condition occurs. In one example, the WTRU may be preconfigured with a resource reselection counter and a trigger condition.

[0073] Therefore, LTE Mode 4 semi-persistent scheduling can be applied to NR SL periodic traffic. In addition, NRV2X can support many advanced use cases based on aperiodic traffic. In addition, how Mode 2 operation handles aperiodic traffic and the corresponding resource reservation can vary.

[0074] There may be issues with CSI-RS transmission instances. The NR V2X SL may only support CSI-RS transmission together with PSSCH transmission. Therefore, unlike NR Uu CSI-RS transmission, there is no periodic CSI-RS transmission available for the WTRU to periodically update the CSI under SL. The PSSCH transmission instances may be based on traffic patterns, such as periodicity and burstiness of data. Sending CSI-RS in every data transmission (i.e., every PSSCH transmission) may result in unnecessary overhead, for example when there is a large amount of data to be transmitted in a slowly varying channel. Considering the CSI report transmission, it may also reduce the resource utilization efficiency in Mode 2 operation.

[0075] In addition, non-subband CSI based on the PSSCH transmission bandwidth may be problematic. CSI-RS transmission may be limited to the PSSCH transmission. Therefore, the associated report may only apply to PSSCH resource allocation in the frequency domain. Since PSSCH resource allocation may be based on data packet size, PSSCH transmission of small packets may occupy one or several subchannels, which may not provide accurate non-subband CSI reporting.

[0076] In some examples, higher congestion from CSI reporting may occur. A transmitting WTRU for sidelink unicast may trigger aperiodic CSI reporting for the sidelink, which may increase congestion in the resource pool because a receiving WTRU that is triggered to report CSI may need to send a sidelink transmission even though the receiving WTRU may not have any packets to send.

[0077] In other examples, there may be issues with CSI reporting timing. In NR V2X, explicit CSI reporting may not be used. Therefore, the transmitting WTRU may wait indefinitely for a triggered CSI report. The receiving WTRU may report the triggered CSI at any time when sidelink resources are available. In high mobility scenarios, delayed CSI feedback may be outdated and useless by the time the transmitting WTRU receives the CSI report.

[0078] In another example, sidelink resource selection may be problematic. In WTRU autonomous resource selection, such as in Mode 2, the WTRU may select one or more sidelink resources based on sensing. During the sensing process, the WTRU may first select a subset of subchannels based on decoding of Reference Signal Received Power (RSRP) / Sidelink Control Information (SCI), and then the WTRU may randomly select one or more subchannels. In one example, the WTRU may select a subchannel with an RSRP below a threshold. However, the availability of CSI in each subchannel may not be considered.

[0079] Sidelink transmit WTRU, transmit WTRU, transmitter WTRU, sidelink TxWTRU, Tx WTRU and first WTRU may be used interchangeably and remain consistent with the examples and embodiments provided herein. In addition, sidelink receive WTRU, receive WTRU, sidelink RxWTRU, Rx WTRU, receiver WTRU and second WTRU may be used interchangeably and remain consistent with the examples and embodiments provided herein.

[0080] In addition, sidelink CSI may be used interchangeably with CSI and still be consistent with the examples and implementations provided herein. In addition, a sidelink measurement reference signal for CSI measurement may be referred to as a sidelink CSI reference signal (S-CSI-RS) and may be used interchangeably with CSI-RS and still be consistent with the examples and implementations provided herein.

[0081] In addition, measurement reference signal (RS), sidelink measurement RS, CSI-RS, sidelink CSI-RS, S-CSI-RS, demodulation RS, DM-RS, sidelink DM-RS, S-DM-RS, PTRS, sidelink PTRS, S-PTRS, RLM-RS, sidelink RLM-RS, S-RLM-RS, RRM-RS, sidelink RRM-RS, S-RRM-RS and beam reference signal can be used interchangeably and can still be consistent with the examples and implementation schemes provided herein. In addition, CSI report, sidelink CSI report, CSI-RS transmission, sidelink CSI-RS transmission, indication of CSI-RS presence and indication of sidelink CSI-RS presence can be used interchangeably and can still be consistent with the examples and implementation schemes provided herein.

[0082] In addition, measurement results, RSRP, RSRQ, RSSI, L1-RSRP and SINR can be used interchangeably and can still be consistent with the examples and implementation schemes provided herein. In addition, time slots can be used interchangeably with subframes, radio frames, logical time slots, side link time slots, Uu time slots, time slots and time slots configured for side link transmissions, and can still be consistent with the examples and implementation schemes provided herein.

[0083] CSI reporting index, CSI reporting identifier, CSI reporting process, CSI process and CSI process identifier may be used interchangeably and may still be consistent with the examples and implementations provided herein. In addition, CSI reporting (CSI reporting, CSIreport), CSI feedback and CSI reporting trigger may be used interchangeably and may still be consistent with the examples and implementations provided herein.

[0084] In some implementations, a sidelink reference signal for CSI measurement may be used. The sidelink CSI may be measured, estimated, or determined based on the reference signal for sidelink CSI measurement, which may be transmitted, signaled, or received on a sidelink resource.

[0085] Thus, different sidelink CSI-RS types may be used. In some examples, one or more of the following may apply to the sidelink CSI-RS. A transmitting WTRU may transmit a CSI-RS on a sidelink resource, where the sidelink resource may be a resource used for a PSSCH transmission. The CSI-RS may be located within a used, selected, or determined PSSCH resource. Additionally, one or more types of CSI-RS may be used.

[0086] The first type of CSI-RS may be a reference signal transmitted for CSI measurement and is present only when CSI feedback is enabled or sidelink measurement is used. For example, radio link modulation (RLM) or radio resource management (RRM) may be used. The first type of CSI-RS may be an RS transmitted separately from a demodulation reference signal (DM-RS) for an associated sidelink channel, such as a PSSCH or a physical sidelink control channel (PSCCH). The associated sidelink channel may be a sidelink channel, which may include an indication of the presence of a CSI-RS, an indication of a CSI report trigger, and / or a subchannel in which the CSI-RS is transmitted. The first type of CSI-RS may be referred to as a measurement CSI-RS (M-CSI-RS).

[0087] The second type of CSI-RS may be a reference signal transmitted due to CSI measurement and is always present in the PSSCH resource, regardless of whether CSI feedback is enabled or disabled. The second type of CSI-RS may be used as a DM-RS for another side link channel (e.g., PSCCH or PSSCH). The second type of CSI-RS may be referred to as a DM-RS when not used for CSI measurement. The temporal density of the second type of CSI-RS may be configured or determined based on one or more transmission parameters of the side link channel (e.g., PSSCH or PSCCH), wherein the transmission parameters may include at least one of a modulation and coding scheme (MCS), a transport block size, a QoS, or a broadcast type.

[0088] When the operating frequency band is above a threshold, a third type of CSI-RS may be used or present. For example, when the operating frequency band is above 6 GHz, a third type of CSI-RS may be used. Otherwise, another type of CSI-RS may be used. The third type of CSI-RS may be referred to as a phase tracking reference signal (PT-RS).

[0089] The CSI-RS position may be determined based on the operating frequency. For example, when the operating frequency is below a threshold (e.g., 6 GHz), the associated CSI-RS may be transmitted in a PSSCH resource that may be scheduled by the PSCCH, where the SCI may trigger a CSI report or indicate the presence of the CSI-RS. In addition, when the operating frequency is above a threshold (e.g., 6 GHz), the associated CSI-RS may be transmitted in a PSSCH resource that may be reserved by the PSCCH, where the SCI may trigger a CSI report or indicate the presence of the CSI-RS.

[0090] Examples of determining CSI-RS types are provided herein. In one example, one or more of the S-CSI-RS types may be used when the WTRU triggers sidelink CSI feedback, and the CSI-RS type may be used for sidelink CSI measurement. For example, a transmitting WTRU may determine which CSI-RS type may be used for CSI report triggering. The CSI-RS type may be determined based on one or more of the following embodiments. In addition, a receiving WTRU may determine which CSI-RS type may be used to measure CSI based on one or more of the following embodiments.

[0091] In one embodiment, the type of CSI-RS used for CSI measurement may be determined based on at least one of the following parameters: maximum rank of PSSCH, slot index, subchannel index, channel busy rate (CBR), QoS, minimum communication range (MCR), mobile speed, indication in SCI, and DM-RS density. In one example, the determination of CSI measurement may be performed between a first type of CSI-RS and a second type of CSI-RS. That is, in one embodiment, a first type of CSI-RS or a second type of CSI-RS may be determined and thus used for CSI measurement. Some of the above parameters for determining the type of CSI-RS will be described in detail below.

[0092] For example, if the maximum rank is less than a threshold for CSI feedback and / or sidelink transmission, a second type of CSI-RS (e.g., DM-RS for PSSCH) may be used. Otherwise, a first type of CSI-RS (e.g., M-CSI-RS) may be used. In one example, the threshold may be 2. Thus, for example, if the maximum rank for unicast is 1, DM-RS for PSSCH may be used for CSI measurement. Otherwise, M-CSI-RS may be used.

[0093] In another example, the slot index may relate to a slot for RLM or RRM measurements. If the CSI-RS is transmitted in a slot where the WTRU may need to measure RLM or RRM, a first type of CSI-RS (e.g., M-CSI-RS) may be used. Otherwise, a second type of CSI-RS (e.g., DM-RS for PSSCH) may be used.

[0094] In another example, a subchannel index may be used. For example, one or more subchannels within a resource pool may be configured for a specific purpose. The purpose may include, for example, physical sidelink feedback channel (PSFCH) transmissions. A second type of CSI-RS may be used for those subchannels, otherwise a first type of CSI-RS may be used. For example, when a subchannel includes a PSFCH resource, a DM-RS for the PSSCH may be used for CSI measurements.

[0095] In another example, if the CBR is above a threshold, the second type of CSI-RS may be used. Otherwise, the first type of CSI-RS may be used for CSI measurement. For example, the threshold may be 40%.

[0096] In addition, if the QoS of the unicast link is above the threshold, the first type of CSI-RS may be used. Otherwise, the second type of CSI-RS may be used for CSI measurement. For example, the threshold may be associated with a quantized value between 1 and 8 (3 bits). For example, the QoS may be the worst case of QoS or the best case of QoS.

[0097] In the example involving MCR, if the receiving WTRU is within the MCR, a first type of CSI-RS may be used. Otherwise, a second type of CSI-RS may be used.

[0098] In an example involving mobile speed, if the relative speed or WTRU speed is above a threshold, the second type of CSI-RS may be used. Otherwise, the first type of CSI-RS may be used. For example, the threshold may be XXXX.

[0099] In an example involving an indication in an SCI, when a WTRU triggers CSI feedback, the WTRU may indicate which type of CSI-RS is used for CSI feedback in the associated SCI. In one example, the indication may be explicit. In another example, the indication may be implicit.

[0100] In yet another example, if the DM-RS density of the PSSCH is higher than a threshold, the second type of CSI-RS may be used. Otherwise, the first type of CSI-RS may be used. For example, the threshold may be XXXX.

[0101] The maximum rank indicator (RI) value may be limited based on the number of antenna ports used for the second type of CSI-RS. The number of antenna ports may be determined based on the transmission rank of a side link channel (e.g., PSSCH or PSCCH) of the second type of CSI-RS. That is, when the second type of CSI-RS is used, the maximum RI value may be limited based on the transmission rank of the side link channel.

[0102] Based on the type of CSI-RS used, the resource element (RE) rate matching of the PSSCH may be different. For example, when a first type of CSI-RS is used, one or more PSSCH REs that may overlap with the first type of CSI-RS may be rate matched. In addition, when a second type of CSI-RS is used, the PSSCH REs may not be rate matched due to the CSI-RS. In addition, perforation may be used instead of rate matching of the PSSCH REs. For perforated PSSCH REs, the WTRU may send a zero energy signal on the RE or may not send any signal on the RE. For rate-matched PSSCH REs, the WTRU may not consider the RE as an available RE for PSSCH transmission. In addition, the transmitting / receiving WTRU may understand which REs may be perforated or rate matched based on which type of S-CSI-RS may be used.

[0103] The determination, selection, or both between rate-matched PSSCH REs and punctured PSSCH REs may also depend on the data QoS. For example, for data with higher reliability requirements, rate-matched PSSCH REs may be applied. Otherwise, punctured PSSCH REs may be applied. The determination, selection, or both between rate-matched PSSCH REs and punctured PSSCH REs may jointly depend on the data QoS and the type of S-SCI-RS used.

[0104] First, the sidelink CSI reporting is described. In some examples, the WTRU may trigger, activate, or deactivate the sidelink CSI reporting to determine the sidelink channel quality. The triggering of the sidelink CSI reporting may include one or more of the following embodiments.

[0105] The transmitting WTRU may request reporting / feedback of measurements of a sidelink reference signal transmitted from the transmitting WTRU, wherein the measurements may include at least one of CSI, RSRP, reference signal received quality (RSRQ), received signal strength indication (RSSI), or beam quality. In some examples, the CSI may include one or more of CQI, PMI, or RI. In addition, the request may be received by a receiving WTRU, wherein the receiving WTRU may be a WTRU in a sidelink communication (e.g., unicast or multicast).

[0106] Additionally, the transmitting WTRU may send a measurement RS which may be at least one of a CSI-RS, a beam measurement reference signal (BM-RS), a demodulation reference signal (DM-RS) for PSCCH and / or PSSCH, a phase tracking reference signal (PT-RS), a radio link modulation reference signal (RLM-RS), or a radio resource management reference signal (RRM-RS). The measurement RS may be transmitted in a PSSCH resource, wherein the measurement RS may be transmitted when the transmitting WTRU has sidelink data to send.

[0107] In addition, the time / frequency position of the measurement RS within the associated PSSCH resource may be indicated in the associated PSCCH, where the PSSCH resource may be one or more subchannels within a resource pool. If the associated PSSCH occupies more than one subchannel, the measurement RS may be transmitted in a subset of the subchannels. The subchannel position may be predefined (e.g., the first subchannel, the middle subchannel, or the last subchannel). In addition, the subchannel position may be determined based on one or more of the following parameters: identity, QoS, CBR, MCR, and determination within or outside coverage. In the example, the identity may be a source id, a destination id, or both. In addition, the subchannel position may be configured via PC5-Radio Resource Control (RRC).

[0108] Additionally, the transmitting WTRU may send an indication to trigger a sidelink CSI report, where the indication may be at least one of the following parameters: a bit field in the associated SCI, source=id, or a slot number or index. These parameters are described in detail below.

[0109] In examples where a bit field is included in the associated SCI, the bit field may indicate one or more of: presence of a measured RS, time / frequency location of a measured RS, transmission power level (or ratio) of a measured RS, periodic reporting, or aperiodic reporting.

[0110] In one example, a receiving WTRU may receive an SCI from a source ID that may be preconfigured or predetermined. The receiving WTRU may measure the sidelink CSI and report. One or more of the source IDs may be used from the transmitting WTRU. In addition, a first source ID may indicate that there is no sidelink CSI trigger (e.g., there is no measurement RS), while a second source ID may indicate a sidelink CSI trigger (e.g., there is a measurement RS). In addition, the source ID may be used interchangeably with the destination ID and may still be consistent with the examples and implementations provided herein. In an example that includes a timeslot number or index, if the receiving WTRU receives an SCI in a particular timeslot, the receiving WTRU may measure the sidelink CSI and report.

[0111] In one example, the transmitting WTRU may be triggered to transmit a CSI-RS (and / or CSI report) in a PSSCH transmission when one or more of the following thirteen conditions are met.

[0112] First, resource selection can be triggered by higher layers.

[0113] Second, the CBR may be above a threshold or below a threshold.

[0114] Third, a HARQ NACK may have been received. A HARQ-NACK may be received N times consecutively from the same WTRU, where N may be configured, predefined or indicated.

[0115] Fourth, a timer may have expired. For example, the WTRU may set a timer at the start of the last received CSI report, and the timer value may be based on transport block (TB) QoS requirements (e.g., reliability and latency), estimated channel conditions (e.g., coherence time of the channel), and / or WTRU speed.

[0116] Fifth, the QoS requirements of the TB may have changed. For example, the reliability requirements of the TB may have changed. The worst case QoS requirements may change, where the worst case QoS may be a QoS requiring one or more of the following: shortest delay, highest reliability, maximum range, highest data rate, and maximum packet size.

[0117] Sixth, transmission parameters and / or schemes may be changed. For example, the rank number may be changed.

[0118] Seventh, the size of a TB may have changed.

[0119] Eighth, the received RSRP and estimated PL may have changed.

[0120] Ninth, the WTRU transmit-receive distance may have changed. For example, when the transmit-receive distance may exceed a threshold, the transmitting WTRU may request a CSI report.

[0121] Tenth, a new unicast (or multicast) link can be established.

[0122] Eleventh, the region id of the transmitting WTRU and / or the receiving WTRU may change.

[0123] Twelve, a DTX for a sidelink transmission may be received. For example, after a sidelink transmission, the transmitting WTRU may receive a DTX in the associated HARQ resources and the transmitting WTRU may be triggered to transmit a CSI-RS and its associated CSI report.

[0124] Thirteenth, a CSI-RS request indication may be received from a receiving WTRU. The CSI-RS request indication may be an RRC message, a MAC control element (CE), or may be included in an SCI. The receiving WTRU may send a CSI-RS request indication under one or more of the following trigger conditions: (1) N consecutive PSCCH and / or PSSCH decoding errors; (2) a change in the WTRU transmit-receive distance, or (3) a change in the area id of the receiving WTRU.

[0125] In another embodiment, the WTRU may not be allowed to trigger sidelink CSI reporting when one or more of the following ten conditions are met.

[0126] First, the CBR may be above (or below) a threshold, where the threshold may be determined based on one or more of the following parameters: QoS (or worst case QoS), transmit-receive distance, within the MCR (e.g., the transmit-receive distance is within the minimum required communication range) or outside the MCR (e.g., the transmit-receive distance is outside the minimum required communication range), or within the coverage range or outside the coverage range.

[0127] Second, a HARQ-ACK for the most recent sidelink transmission may be received. Alternatively, N consecutive HARQ-ACKs for the previously transmitted sidelink transmissions may be received.

[0128] Third, the received power of HARQ-ACK may be higher than a threshold.

[0129] Fourth, the measured RSRP of the reference signal transmitted from the receiving WTRU may be above a threshold.

[0130] Fifth, the transmit beam may be the same as the most recent sidelink transmission (for which HARQ-ACK was received).The transmit beam may be referred to as an indication of a reference signal index for a quasi-co-located Type D indication or a transmit channel indication (TCI) state.

[0131] Sixth, QoS is below a threshold. For example, the condition may include one or more of the following: (1) minimum communication range is below a threshold; (2) reliability is below a threshold; (3) priority is below a threshold; (4) data rate is below a threshold; (5) packet size is less than a threshold.

[0132] Seventh, the transmitting WTRU (and / or the receiving WTRU) may be out of coverage (or in coverage).

[0133] Eighth, the configuration may indicate that sidelink CSI feedback is not allowed. The configuration may be at least one of: a higher layer configuration from the network, a resource pool configuration, a unicast configuration between two unicast WTRUs via PC5-RRC, or a multicast configuration.

[0134] Ninth, the transmitting WTRU may receive an out-of-coverage indication from the receiving WTRU. In addition, the CQI table may include a CQI field indicating out-of-coverage, and this CQI field may be used in the following situations: there are no other CQI values ​​applicable to the current channel conditions; the receiving WTRU is outside the MCR; and / or the current channel conditions cannot meet the QoS of the packet.

[0135] Tenth, the transmitting WTRU receives N consecutive DTXs of the sidelink transmission, where N may be a non-negative integer.

[0136] Sidelink CSI reporting depending on one or more measurement RSs will be described below. CSI reports may be transmitted in MACCE or in physical layer signaling (e.g., similar to UCI on PUSCH in NR Uu link). It may be possible to support MACCE-based and physical layer signaling-based CSI reporting. The choice between these two schemes may depend on one or more of the following two conditions. The first condition relates to the type of CSI-RS. For example, when a first type of CSI-RS is used for CSI measurement, a MAC CE-based report may be used, and when a second type of CSI-RS is used for CSI measurement, a physical layer signaling-based CSI report may be used. The second condition relates to (pre) configuration. The CSI report may be part of the configuration in link establishment, or may be part of the resource pool configuration. In the example, the configuration may be performed by pre-configuration.

[0137] The examples provided herein may include a dynamic sidelink CSI-RS indication. For example, the transmitting WTRU may indicate the presence of a CSI-RS transmission in the SCI. The WTRU may be configured with a CSI-RS pattern set for a resource pool, and the SCI indication may be an index to the configured set. In one example, the WTRU may be pre-configured with a CSI-RS pattern set. The CSI-RS pattern may be defined, for example, on a subchannel basis, and the transmitting WTRU may indicate in the SCI one or more of: CSI-RS in each subchannel used by the PSSCH, CSI-RS in the subchannels used by the PSCCH, or CSI-RS in a subset of the subchannels used by the PSSCH.

[0138] In one example, the transmitting WTRU may indicate in the SCI QoS requirements associated with CSI-RS transmission (and / or CSI reporting), where the QoS requirements may include one or more of the following requirements.

[0139] First, CSI reporting can be applied to the QoS requirements of PSSCH transmission. The latency requirements of QoS can determine the reporting timing of the triggered CSI feedback.

[0140] Second, CSI-RS may be transmitted within PSCCH, and its associated PSCCH (e.g., in SCI) may indicate the presence of CSI-RS and / or the triggering of CSI reporting, and SCI may indicate the QoS of its associated PSSCH. The QoS of CSI-RS (and / or CSI reporting) may be determined based on the QoS of the PSSCH transmitted together in the time slot.

[0141] Third, the QoS associated with the CSI-RS (and / or CSI report) and the QoS associated with the PSSCH may be separately indicated. For example, one or more QoS indications may be in the SCI, and the first QoS indication may be associated with the PSSCH, while the second QoS indication may be associated with the CSI report. In addition, the number of bits of the first QoS and the second QoS may be different. For example, the QoS parameters for the second QoS may be a subset of the QoS parameters for the first QoS. For example, the first QoS may include one or more of the following QoS parameters: payload (bytes), transmission rate (messages / second), maximum end-to-end delay (ms), reliability (%), data rate (Mbps), or minimum required communication range (meters). The second QoS may include a subset of the above QoS parameters. For example, the second QoS may include: maximum end-to-end delay (ms); reliability (%); minimum required communication range (meters).

[0142] Additionally, the QoS associated with the CSI-RS (and / or CSI reporting) may be a subset of the QoS parameters associated with the PSSCH. For example, a receiving WTRU may only use a subset of the QoS parameters of the QoS associated with the PSSCH.

[0143] In another example, the transmitting WTRU may be configured with a CSI-RS density and / or resource configuration based on the QoS requirements, and the receiving WTRU may determine the QoS requirements associated with the CSI-RS transmission accordingly. In one example, the WTRU may be pre-configured with the CSI-RS density and / or resource configuration. Additionally, the CSI-RS QoS requirements may be configured to be the same as the requirements for the accompanying PSSCH transmission. In one example, the CSI-RS QoS requirements may be pre-configured.

[0144] In an embodiment, the WTRU may perform resource selection, resource reselection, or both for CSI report transmission. Alternatively or in addition, the WTRU may perform resource selection, resource reselection, or both for CSI-RS transmission. The transmitting WTRU may transmit a CSI-RS to the receiving WTRU and trigger measurements of the CSI-RS transmission. Once the receiving WTRU has performed relevant measurements of the CSI-RS transmission, it will transmit a CSI report to the transmitting WTRU. The MAC layer of the WTRU may receive the CSI report from its PHY layer. The transmitting WTRU may perform resource selection, resource reselection, or both based on the reception timing of the CSI feedback / CSI report from the lower layers.

[0145] In one embodiment, the WTRU may trigger resource selection to reserve sidelink resources if the WTRU does not have any pending SL grants for sidelink transmission to transmit a CSI-RS MAC CE. In another embodiment, if the WTRU has one or more pending SL grants, but these grants do not meet specific criteria associated with CSI-RS reporting, such as in the following example, the WTRU may trigger resource selection, resource reselection, or both.

[0146] In one embodiment, the WTRU may trigger a SL-Buffer Status Report (BSR) if the WTRU has no pending grants for sidelink transmission to transmit a CSI-RS MAC CE. In another embodiment, the WTRU may trigger a SL-BSR if the UE has one or more pending SL grants but these grants do not meet specific criteria associated with CSI-RS reporting, such as in the following example.

[0147] In one example, one or more pending grants may not occur within a time window or required delay associated with CSI-RS reporting. Such a window may be determined based on the mechanisms defined in the present disclosure.

[0148] In another example, based on some restrictions such as in the following examples, one or more pending grants may not be used for transmission of the CSI-RS report. In one example, a logical channel associated with a MAC CE transmission cannot be transmitted on a grant due to restrictions associated with the logical channel. In another example, based on the method for priority determination described in the present disclosure, the priority of the determined MAC CE may be such that the MAC CE cannot be transmitted on the grant due to restrictions associated with the logical channel. In another example, the grant may be associated with a destination identifier (ID) that does not match the destination to which the CSI-RS report should be sent.

[0149] In addition, a WTRU performing resource selection, resource reselection, or both associated with a pending MAC CE may provide QoS information to the physical (PHY) layer for performing resource selection. In one example, the QoS information may include priority information.

[0150] In one example, the WTRU may determine the priority information by first deriving the L2 priority associated with the MAC CE. The MAC CE may then be treated similarly to any pending data that has triggered resource selection, and QoS information needs to be provided to the PHY layer for resource selection. Specifically, the WTRU MAC may derive the L1 priority from the derived L2 priority, for example based on a pre-configuration, and may provide such L1 priority to lower layers. The PHY layer may select a resource selection window, such as a value of T2, within which to perform resource selection based on the provided L1 priority. The L2 priority associated with the MAC CE may be derived using any of the methods described in the present disclosure for determining the L2 priority for the Logical Channel Prioritization (LCP) process.

[0151] In another example, the WTRU may first derive the L2 priority associated with the MAC CE based on the CSI feedback reporting window associated with the CSI feedback (which may be determined as described in the present disclosure). Specifically, the WTRU may first determine the CSI feedback window using the method described in the present disclosure. The WTRU may then determine which of the one or more logical channels configured by the WTRU is configured with a QoS flow with similar delay requirements. In one example, the delay requirement may be expressed by a PC5 5G QoS characteristic (5QI) (PQI). Specifically, the WTRU may select a logical channel (LCH) for which the mapped QoS flow has a delay requirement that is less than or equal to the delay associated with the delay required for CSI feedback, the delay window, or both. Alternatively, the WTRU may select an LCH for which the mapped QoS flow has a delay that is closest to the delay required for CSI feedback, the delay window, or both.

[0152] In another example, the WTRU may first derive an L2 priority associated with the MAC CE based on a CSI feedback reporting window associated with the CSI feedback (as determined in the examples described in the present disclosure). In such an example, the WTRU may first determine the CSI feedback window using the methods described in the present disclosure. The WTRU may then determine the L2 priority associated with such a window. Specifically, the WTRU may select an L2 priority whose delay corresponding to the L2 priority is less than or equal to the CSI feedback window delay. The WTRU may then provide such priority to the lower layers for resource selection, resource reselection, or both. The WTRU may apply such priority in resource selection performed by the lower layers, in a resource reselection process performed at the lower layers, or in both.

[0153] In another example, the WTRU may provide a CSI feedback reporting window delay or delay bound to its PHY layer. The CSI feedback reporting delay or delay bound may be in the form of a remaining packet delay budget (PDB) for the data to be transmitted that triggered the resource selection. The WTRU may apply the CSI feedback reporting window delay or delay bound. The CSI feedback reporting window delay or delay bound may be in the form of a remaining PDB of a TB that will be transmitted in a resource selection process performed by the PHY layer, a resource reselection process performed by the PHY layer, or both, and is triggered by the TB. Specifically, the WTRU may determine the remaining PDB to be used in resource selection based on the CSI delay bound or the CSI feedback window. The WTRU may determine the remaining PDB as the remaining delay up to the CSI delay bound or the CSI feedback window. The remaining PDB provided to the PHY layer may represent the configured CSI feedback reporting window delay or delay bound. Alternatively or in addition, the WTRU may determine the PDB as the closest PDB associated with any data logical channel such that the determined PDB is less than the CSI feedback reporting window delay or delay bound. The PHY layer may provide the MAC layer with a set of resources that satisfy the remaining PDB, so that the MAC layer may select from these resources for transmission of the CSI feedback MAC CE. In one example, the MAC layer may select randomly.

[0154] In another example, the WTRU may indicate to the PHY layer that resource reselection is associated with the transmission of the CSI feedback MAC CE. The MAC layer may also provide a window to the PHY layer, or the MAC layer may indicate to the PHY layer a specific destination address or identifier of the MAC CE that triggered the reselection, so that the PHY layer may select resources based on the window.

[0155] In some embodiments, the WTRU may determine the L2 source, L2 destination, or both of the CSI report MAC CE. The WTRU may receive CSI-RS reports from its PHY layer and may have multiple ongoing unicast links. During MAC layer multiplexing, the WTRU may determine the L2 destination ID to which a particular MAC CE will be transmitted. To do this, the WTRU needs to be able to associate the CSI-RS report received from the lower layers with the specific unicast link for which the report is intended.

[0156] In one example, the WTRU may receive a CSI-RS report from a lower layer along with a decoded MAC PDU. The WTRU may determine the unicast link to which the CSI-RS report will be transmitted, for example, using the L2 source / destination ID of the CSI-RS report by determining the L2 destination / source ID in the decoded MAC PDU sent with the CSI-RS report. Specifically, the L2 destination address of the CSI-RS report may include the L2 source ID of the decoded MAC PDU, and the L2 source ID of the CSI-RS report may include the L2 destination ID of the decoded MAC PDU.

[0157] In another example, if the WTRU or the MAC layer of the WTRU cannot decode the MAC PDU, the WTRU may discard the CSI-RS report. The WTRU may not be able to decode the MAC PDU because the WTRU, for example, cannot determine the L2 source / destination ID or cannot find a unicast link with the associated L2 source / destination ID indicated in the MAC PDU.

[0158] In an example, the LCP procedure may take into account the CSI-RS feedback MAC CE. The WTRU may take into account the presence of the MAC CE in the sidelink LCP procedure. In an example, the WTRU may prioritize destination address selection based on the destination address having one or more pending MAC CEs for transmission.

[0159] In another example, the WTRU may assign a delay value or a delay bound value to the SL CSI MAC CE. Such a value may be determined by the process in any of the related examples described in this disclosure.

[0160] In another example, the WTRU may assign an L2 priority to the SL CSI-RS feedback MAC CE. The WTRU may perform the SL LCP by selecting the destination address with the highest priority data or MAC CE to be transmitted. The L2 priority of the MAC CE carrying the SL CSI report may be determined based on one or more of the following priorities: a pre-configured priority, a priority of the received data, or a priority of the LCH associated with the transmission to the peer WTRU. Therefore, the WTRU may assign a priority to the CSI feedback transmission. In one example, the CSI feedback transmission may be used for resource selection. Some of the above priorities are further described below.

[0161] In one embodiment, the L2 priority of the MAC CE carrying the SL CSI report may be determined based on a pre-configured priority. In one example, the WTRU may consider the SL MAC CE to have the highest / lowest priority compared to other SL LCHs. In another example, the network may configure the L2 priority associated with the SL MAC CE in the system information block (SIB) / dedicated signaling / out of coverage (OOC) pre-configuration.

[0162] In one embodiment, the L2 priority of a MAC CE carrying a SL CSI report may be determined based on the priority of the received data. In one example, the WTRU may consider the SL MAC CE to have the same priority as or a priority derived from a peer WTRU transmission that has measured the SL-CSI. For example, the WTRU may derive the L2 priority of the MAC CE from the L1 priority received in the transmission carrying the measured CSI-RS. The mapping of L2 priority to L1 priority may be configurable at the WTRU or pre-configured at the WTRU. In another example, the WTRU may derive the L2 priority from the LCH.

[0163] In one embodiment, the L2 priority of a MAC CE carrying a SL CSI report may be determined based on the priority of the LCH associated with the transmission to the peer WTRU. In one example, the WTRU may determine the L2 priority of a SL MAC CE for transmission to a destination WTRU that needs to transmit a CSI-RS MAC CE based on the LCH configured at the WTRU. For example, the WTRU may determine the L2 priority of the MAC CE as the highest / lowest L2 priority associated with any configured LCH at the WTRU that has the same destination address as the intended destination of the MAC CE.

[0164] Examples involving CSI-RS transmission dropping are provided herein. A WTRU may drop a CSI-RS transmission based on one or both of the following conditions.

[0165] First, if the CBR is above a threshold, the WTRU may discard the CSI-RS transmission. For example, the WTRU may be configured with a CBR threshold for the SL resource pool on which the CSI-RS report should be transmitted. If the CBR is above the CBR threshold, the WTRU may discard the transmission of the CSI-RS report.

[0166] Second, if the timer expires, the WTRU may discard the CSI-RS transmission. In other words, the WTRU may discard the CSI-RS transmission based on the expiration of the timer. For example, the WTRU may start the timer when a CSI-RS report is received from the PHY layer. Upon expiration of the timer, the MAC layer may discard the pending and not yet transmitted CSI-RS report MAC CE. The value of the timer may be set based on a mechanism similar to the mechanism described in the present disclosure for setting the reporting window.

[0167] Reference below Figure 2 A method 200 according to an embodiment of the present disclosure is described. Figure 2 is a flow chart illustrating method 200. Method 200 may be used by a WTRU (e.g., a receiving WTRU) that is capable of communicating with a network or another WTRU (e.g., a transmitting WTRU) via a SL. The WTRU is configured with an SR configuration set. In the present disclosure, unless otherwise stated, a WTRU performing method 200 may be referred to as a receiving WTRU. A WTRU that transmits a signal (e.g., CSI-RS, data, etc.) to a receiving WTRU may be referred to as a transmitting WTRU, a network, or a base station. In the present disclosure, unless otherwise stated, the terms "transmitting WTRU", "base station", and "network" may be used interchangeably. A WTRU that receives CSI-RS, SL grants, and other signals from a network may be referred to as a receiving WTRU.

[0168] The method 200 may include: at 201, receiving (1) a CSI report request for requesting a CSI report and (2) CSI report delay information of the CSI report through the SL; at 202, starting a timer based on the received CSI report delay information; at 203, triggering SR transmission specific to the CSI report; and at 204, determining whether a SL grant has been received before the timer expires. Under the condition that the SL grant has been received before the timer expires, the method 200 may further include: at 205, transmitting the CSI report based on the SL grant. And under the condition that the SL grant has not been received before the timer expires, the method 200 may further include: at 206, discarding the CSI report. The above-mentioned different processes from 201 to 206 will be further described with reference to detailed embodiments below.

[0169] Thus, the WTRU is capable of communicating with a network via a side link (SL), and the WTRU is configured with a scheduling request (SR) configuration set. In addition, the WTRU includes a transceiver and a processor. The transceiver is configured to receive (1) a CSI report request requesting a CSI report and (2) CSI report delay information for the CSI report via the SL. The processor is configured to: start a timer based on the received CSI report delay information; trigger an SR transmission specific to the CSI report; and determine whether an SL grant has been received before the timer expires. Under the condition that the SL grant has been received before the timer expires, the processor is further configured to transmit the CSI report via the transceiver based on the SL grant. And under the condition that the SL grant has not been received before the timer expires, the processor is further configured to discard the CSI report. It should be noted that the WTRU may also include additional components, such as memory, circuits, batteries, etc. It is assumed that these additional components are well known, and therefore a detailed description of these additional components will be omitted from the present disclosure. The WTRU and its transceiver and processor will be further described below with reference to detailed embodiments.

[0170] At 201, method 200 may include receiving, via a SL, (1) a CSI reporting request for requesting a CSI report and (2) CSI reporting delay information for the CSI report. The processing at 201 may be performed by a receiving WTRU.

[0171] The transmitting WTRU may transmit a CSI-RS to the receiving WTRU and request reporting / feedback of measurements of the CSI-RS transmitted from the transmitting WTRU. In one example, the transmitting WTRU may transmit a CSI report request together with the CSI-RS. In another example, the CSI report request may be an indication of an RRC message or a MAC CE. In yet another example, the CSI report request may be included or indicated in the SCI. It should be understood that although some examples of CSI report requests have been discussed above, they are not intended to be exclusive or to limit the CSI report requests disclosed in the present disclosure. Other types of CSI report requests may be available as long as they can help implement the principles of the present disclosure.

[0172] In one example, CSI report delay information for a CSI report may be provided from the network or a transmitting WTRU (e.g., via PC5 RRC signaling). In one example, CSI report delay information for a CSI report may be preconfigured in a receiving WTRU. In one example, the CSI report delay information may also be determined based on one or more of the following parameters: one or more QoS parameters, CBR, MCR (e.g., inside MCR or outside MCR), coverage (e.g., inside coverage or outside coverage), mode (mode 1 or mode 2), broadcast type (e.g., multicast or unicast), maximum rank or mobile speed (or relative speed between two WTRUs). In one example, the CSI report delay information may be received via MAC CE / RRC signaling. It should be noted that the above examples are not intended to be exclusive or to limit the CSI report delay information. The CSI report delay information may be generated / determined by any other available method as long as the CSI report delay information can help implement the principles of the present disclosure.

[0173] In one example, the CSI report delay information may be an information set including a CSI report delay or a CSI report delay bound. The delay / delay bound is the same or similar to that discussed above in the present disclosure. The delay / delay bound will be further described below with reference to a detailed example. It should be noted that the delay / delay bound / delay information involves a delay value. Therefore, in the present disclosure, unless otherwise specified, the terms "delay", "delay value", "delay bound", "delay bound value", "window", "delay window" and "delay information" are used interchangeably.

[0174] The method 200 may then proceed to 202. At 202, the method 200 may include starting a timer based on the received CSI report delay information. In one example, the receiving WTRU may start the timer, with the starting point being the time when the CSI report request is received. In one example, the timer value may be based on the delay / delay bound in the CSI report delay information. The timer may be implemented by a processor using software, an algorithm, etc. It should be noted that the above examples are not intended to be exclusive or to limit the timers disclosed in the present disclosure.

[0175] The method 200 may then proceed to 203. At 203, the method 200 may include triggering a CSI reporting specific SR transmission. The SR transmission may be a transmission from a receiving WTRU to a transmitting WTRU (which sends a CSI-RS to the receiving WTRU). The CSI reporting specific SR transmission may indicate that the receiving WTRU wants to perform CSI reporting and thus trigger the transmitting WTRU or the network to determine / allocate sidelink resources for CSI reporting.

[0176] The process at 203 may further include: selecting an SR configuration from the SR configuration set based on the received CSI report delay information; and transmitting the SR to the network / base station based on the SR configuration. In one example, the SR configuration set may include multiple SR configurations, and the WTRU may select the desired SR configuration from the multiple SR configurations based on the CSI report delay information received at 201. For example, the SR configuration may indicate the PUCCH resources used for SR transmission. The SR configuration may also include other parameters such as timing, time slot, frequency, etc. It should be noted that the above parameters regarding the SR configuration are not intended to be exclusive or to limit the SR configuration. After selecting / determining the SR configuration, the receiving WTRU may transmit the SR to the transmitting WTRU (which sends the CSI-RS to the receiving WTRU) or the network based on the SR configuration.

[0177] In one example, each of the SR configuration sets is associated with preconfigured CSI report delay information from a preconfigured CSI report delay information set. The preconfigured CSI report delay information set may include multiple preconfigured CSI report delay information. In general, the preconfigured CSI report delay information may be similar to the above-mentioned CSI report delay information for CSI reporting. For example, the preconfigured CSI report delay information is also determined based on one or more of the following parameters: one or more QoS parameters, CBR, MCR (e.g., within MCR or outside MCR), coverage (e.g., within coverage or outside coverage), mode (mode 1 or mode 2), broadcast type (e.g., multicast or unicast), maximum rank, or mobile speed (or relative speed between two WTRUs). The preconfigured CSI report delay information may be preconfigured by the receiving WTRU, the transmitting WTRU, or the network. For example, the preconfigured CSI report delay information may be preconfigured or predetermined by the transmitting WTRU, and then the transmitting WTRU may transmit the preconfigured CSI report delay information to the receiving WTRU.

[0178] The preconfigured CSI report delay information may include a CSI report delay (e.g., 10ms, 20ms, etc.) or a CSI report delay bound. In one example, one preconfigured CSI report delay information may include only one CSI report delay (or delay bound). In the preconfigured CSI report delay information set, there are two preconfigured CSI report delay information, i.e., two CSI report delays (i.e., one is 10ms and the other is 20ms). Meanwhile, the SR configuration set includes two SR configurations (i.e., a first SR configuration and a second SR configuration). In this case, the first SR configuration may be associated with a CSI report delay of 10ms, and the second SR configuration may be associated with a CSI report delay of 20ms. It should be noted that the above examples regarding SR configurations and preconfigured CSI report delay information sets are not intended to be exclusive or to limit the present disclosure.

[0179] In one example, the WTRU may be configured with a mapping of an SR configuration set to a preconfigured CSI reporting delay information set. The mapping may indicate the relationship between the SR configuration and the preconfigured CSI reporting delay in the preconfigured CSI reporting delay information. In one example, multiple SR configurations may be mapped to one preconfigured CSI reporting delay. In this case, the receiving WTRU may select an SR configuration from multiple SR configurations for CSI reporting based on the priority of the SR configuration. In one embodiment, the mapping may be preconfigured by the receiving WTRU. In another example, the mapping may be provided from the base station. It should be noted that the above descriptions of the mapping are given by way of example only, and they are not intended to be exclusive or to limit the present disclosure.

[0180] In one embodiment, the method 200 may further include providing the calculated delay for the CSI report to the network or the transmitting WTRU. In one example, the calculated delay may be the current delay that the receiving WTRU has for CSI reporting. In one example, the calculated delay may be the expected delay that the receiving WTRU may wish to have for CSI reporting. The calculated delay may be the same or similar to the CSI reporting delay described above. For example, the calculated delay may be 10ms, 20ms, etc. The calculated delay may be determined / calculated in a manner similar to that used to determine the preconfigured CSI reporting delay. It should be noted that the above examples of calculated delays are not intended to be exclusive or to limit the present disclosure.

[0181] The method 200 may then proceed to 204. At 204, the method 200 may include determining whether a SL grant has been received before the timer expires. For example, once the base station receives the SR transmission, it may determine and allocate resources to the receiving WTRU, and then transmit to the receiving WTRU a SL grant that may indicate that the receiving WTRU may transmit a CSI report to the base station. The SL grant may also indicate parameters for the CSI report transmission. In one scenario, the receiving WTRU may receive a SL grant before the timer expires, while in another scenario, the receiving WTRU may not receive any SL grant before the timer expires. The processor may perform different processes based on the results of the process at 204. The following description will further describe the process after the process at 204.

[0182] If at 204, the processor determines that the SL grant has been received before the timer expires, the method 200 may proceed to 205. At 205, the method 200 may further include: transmitting the CSI report based on the SL grant. In one example, the CSI report may be transmitted using the SL resources indicated in the SL grant. The SL grant may indicate parameters for the CSI report transmission. Therefore, the processor may control the transmission of the CSI report by the transceiver based on the SL grant.

[0183] If at 204, the processor determines that the SL grant is not received before the timer expires, the method 200 may proceed to 206. At 206, the method 200 may further include discarding the CSI report. In this case, the receiving WTRU will not transmit the CSI report.

[0184] Examples of indications involving reporting SL-CSI to the network are provided herein. The WTRU may indicate that there is a pending SL-CSI report MAC CE to be transmitted in the sidelink in order to receive a sidelink grant from the network. In one example, the WTRU may receive a sidelink grant in mode 1. In one embodiment, when the MAC layer receives a CSI report to be transmitted to a peer WTRU, the WTRU may trigger a report to the network. Specifically, the WTRU may trigger a scheduling request (SR) in the absence of any SL grant. In addition, the WTRU may trigger an SR when the MAC layer receives a trigger to transmit a CSI report and all existing SL grants do not meet the latency requirements of the CSI report to be transmitted. The WTRU may be configured with a dedicated SR resource for indicating the presence of a SL MAC CE to be transmitted. Alternatively or in addition, when the WTRU has a pending SL MAC CE to be transmitted, it may select from one of the configured SL-SR resources. Specifically, the WTRU may select a SL-SR to be triggered when a SL-CSI report is present based on one or more of the following parameters: a predetermined mapping, a network configuration, an LCH, or a priority of a received transmission that triggered the SR transmission. Some of the above parameters are described in detail below.

[0185] In one example, the WTRU may select a SL-SR to be triggered when there is a SL-CSI report based on an explicit mapping of a SL MAC CE predetermined at the WTRU to one of the configured SL-SR resources.

[0186] In another example, the WTRU may select a SL-SR to be triggered when there is a SL-CSI report based on a configuration made by the network. In one example, the configuration may be a pre-configuration. For example, the WTRU may be configured with an LCH to SR mapping, where the LCH associated with the SLMAC CE is part of such mapping. In one example, the WTRU may be configured with a mapping of the delay of the CSI report to the SR configuration. The WTRU may select an SR configured for a CSI report with a given delay requirement. For example, a range of delay values ​​corresponding to each SR configuration may be provided to the WTRU, and when the delay falls within the delay range associated with the SR, the WTRU may select the associated SR configuration. For example, the WTRU may be configured with a limited number of delay values ​​for CSI reporting, and may select an SR configuration associated with each configuration. The delay of the CSI report may be determined by the WTRU based on any of the processes described in the examples of the present disclosure. Therefore, the WTRU may select an SR configuration for SR transmission based on the delay bound of the CSI report that triggered the SR.

[0187] The delay may further be provided by a peer WTRU. In one example, the delay may be provided via PC5 RRC signaling. The current delay may be maintained at the WTRU and may change with events or periodically. For example, the current delay may be maintained at the WTRU and may change each time the WTRU receives a new value of the delay to be used from a peer WTRU or the network. For example, the WTRU may periodically calculate its delay value and maintain the calculated delay value throughout the cycle. In one example, the entire cycle may last until the next calculation. For example, the WTRU may calculate a new delay value when any factor affecting the value (e.g., speed) changes by a specific amount. The delay may be provided to the MAC layer by the PHY layer for SR triggering.

[0188] In another example, the WTRU may select a SL-SR to trigger when there is a SL-CSI report based on the LCH or priority of the received transmission that triggered the SR transmission. For example, the WTRU may determine the priority or LCH of the received transmission that triggered the SL-CSI report and may select a SR of equal priority. In one example, the LCH may be an LCH whose L2 priority is the same as the priority in the received transmission for which the SL_CSI was measured.

[0189] The WTRU may trigger a BSR and may report that there is a CSI report (e.g., a CSI report SLMAC CE) to be sent to the peer WTRU. For example, the WTRU may report the intention to transmit a SL MAC CE as part of the buffer status of a specific logical channel or logical channel group in the BSR. The SLMAC CE may be configured, preconfigured or predefined to a certain logical channel or logical channel group in the sidelink.

[0190] In one example, the WTRU may report the intent to transmit the SL MAC CE by transmitting an explicit indication in the BSR. In another example, the WTRU may report the intent to transmit the SL MAC CE by using a different BSR format.

[0191] The calculated delay may be transmitted via an SR transmission or a control message. In one example, the calculated delay may be transmitted as part of the SR transmission. Thus, when the WTRU receives the SR transmission, it will obtain the calculated delay and use the calculated delay to schedule sidelink resources for transmitting the CSI report.

[0192] For example, the WTRU may provide the network with a calculated CSI delay bound or window determined based on the methods described in the present disclosure. The calculated CSI delay bound or window may help the network schedule sidelink resources for transmitting CSI reports. The WTRU may provide the network with a calculated CSI delay bound or window for CSI reporting implicitly, explicitly, or both.

[0193] In one example, the WTRU may provide a calculation CSI delay bound or window when triggering a CSI report. Specifically, the WTRU may indicate a calculation CSI delay bound or window each time a CSI report is triggered.

[0194] In one example, when the WTRU requests new resources from the network, the WTRU may provide for calculating a CSI delay bound or window. Specifically, when the WTRU decides to request sidelink resources for transmitting a CSI report, the WTRU may indicate a window or delay (or delay bound). For example, the value of the window or delay bound may be associated with a request for resources for transmitting a CSI request.

[0195] In another example, the WTRU may provide a periodic calculation CSI delay bound or window. For example, the WTRU may be configured with periodic reporting of the CSI window and the reporting may apply to the current calculation window for each periodic trigger.

[0196] In another example, the WTRU may provide a calculated CSI delay bound or window when the current / applicable CSI window changes. For example, the WTRU may report the applicable current calculation window when the value changes (perhaps by a specific amount) from the previously reported value.

[0197] The WTRU may report the window explicitly in a control message such as an RRC message or a MAC CE. For example, the WTRU may report the CSI delay bound or window in a sidelink UE information message when a unicast link between the WTRUs is started and / or reconfigured. For example, the WTRU may report the CSI delay bound or window provided by the peer WTRU in PC5-RRC signaling during unicast link establishment.

[0198] The WTRU may implicitly report the window to the network by selecting the UL resource configured for each possible value of the configuration. For example, the WTRU may be configured with different PUCCH resources or SR configurations, each of which is associated with a different delay. The WTRU selects the PUCCH resource or SR configuration for the delay of the triggered CSI report corresponding to the current delay associated with the CSI report.

[0199] In another example, the WTRU may be configured with congestion based transmission parameters specific to CSI report transmissions. In one example, the WTRU may be configured with a specific set of congestion based transmission parameters to be used for transmission of CSI reports. In one example, the congestion based transmission parameters may be used for congestion control. Specifically, for a transmission including a CSI report, the WTRU may determine to use a dedicated set of congestion based transmission parameters configured specifically for such transmissions. Additionally or alternatively, the WTRU may associate the congestion based parameters to be used for CSI report transmissions with one of the configurations for one of the logical channels.

[0200] For example, the WTRU may associate congestion-based parameters with one of the configurations of the highest priority logical channel, the lowest priority logical channel, or both. In one example, the WTRU may also use the congestion-based parameters associated with the highest priority logical channel for transmissions including CSI reports.

[0201] In another example, the WTRU may associate a congestion based parameter with one of the configurations for the logical channel associated with the CSI report request.In one example, the WTRU may use a congestion based parameter associated with a priority in a received SCI that also requests a CSI report.

[0202] Examples involving wideband CSI determination are provided herein. In one example, a PSSCH transmission bandwidth may be used for wideband CSI. In one example, a transmitting WTRU may determine whether resources reserved for PSSCH transmission may provide wideband CSI based on the bandwidth of the PSSCH transmission. For example, the transmitting WTRU may determine PSSCH transmission resources to provide wideband CSI when: the number of subchannels used for PSSCH transmission may be above a threshold; and / or the number of subcarriers used for PSSCH transmission may be above a threshold. The threshold may be based on the total bandwidth of the applied resource pool and / or channel conditions, such as estimated frequency selectivity.

[0203] In addition, the transmitting WTRU may indicate a CSI request in the SCI associated with the CSI-RS transmission. The receiving WTRU may send a CSI report corresponding to the CSI transmission. When a CSI-RS transmission is triggered, the transmitting WTRU may determine the accompanying PSSCH transmission parameters based on a previous CSI report, a (pre)configured CSI report and / or a minimum CSI report.

[0204] In another example, the transmitting WTRU may adjust the received CSI and apply the adjusted CSI to the scheduled PSSCH transmission. For example, the adjustment may be an offset CQI value based on one or more of the following parameters: (1) the frequency difference between the subchannel of the CSI-RS transmission and the subchannel reserved for PSSCH transmission, (2) the estimated channel frequency selectivity, or (3) QoS requirements such as reliability, delay, priority, and minimum communication range (MCR).

[0205] For example, if the frequency difference between the subchannels reserved for PSSCH transmission and the subchannels for CSI-RS transmission is greater than a frequency threshold (e.g., 20 PRBs) and / or the estimated channel frequency selectivity is greater than a selectivity threshold, the transmitting WTRU may apply an offset (e.g., 1 or 2 units) to reduce the received CQI before applying it to the PSSCH transmission. In addition, if the QoS requirement (e.g., the reliability of the PSSCH transmission (e.g., 1E-5)) is higher than that associated with CSI-RS transmission (e.g., 1E-3), the transmitting WTRU may apply an offset (e.g., 4 or 5 units) to reduce the received CQI before applying it to the PSSCH transmission.

[0206] Resource reselection triggering based on CSI-RS requirements is described herein. In one example, when CSI-RS transmission may be triggered and the PSSCH transmission bandwidth may be below a threshold (eg, 2 subchannels), the transmitting WTRU may trigger resource reselection.

[0207] The examples provided herein include multiple CSI-RS transmissions with distributed frequency resources. In one example, a transmitting WTRU may request a CSI report via a CSI-RS transmission set. The transmitting WTRU may select different frequency resource allocations (e.g., subchannels) for each PSSCH transmission including a CSI-RS transmission. The purpose may be to span multiple CSI-RS transmissions across the entire bandwidth. For example, in Mode 1, the base station may schedule pattern-based PSSCH transmissions. In Mode 2, the WTRU may select non-overlapping frequency resources that extend across the system bandwidth for multiple PSSCH / CSI-RS transmissions. The transmitting WTRU may indicate a CSI request in the SCI associated with the last CSI-RS transmission of multiple CSI-RS transmissions. The receiving WTRU may send a CSI report corresponding to the CSI-RS transmission set. The CSI report may be based on measurements in the bandwidth of each CSI-RS transmission. For example, the receiving WTRU may report the CSI average, maximum CSI, and / or minimum CSI of all measurements.

[0208] Examples provided herein include CSI-based sidelink resource selection. In one example, a sidelink mode is disclosed in which a WTRU (or transmitting WTRU) may select a sidelink resource in a resource pool for a sidelink transmission. This sidelink may be referred to as Mode 2. Mode 2 may be used interchangeably with WTRU selected sidelink mode, WTRU autonomous resource selection mode, WTRU selected mode, WTRU determined resource mode, and perception-based resource selection mode.

[0209] Examples provided herein include subchannel priorities. In one example, one or more resource selection schemes (or modes) may be used based on the availability of CSI at the WTRU. For example, if CSI for one or more subchannels in a resource pool is available, a first resource selection scheme may be used. If CSI for one or more subchannels in a resource pool is not available, a second resource selection scheme may be used.

[0210] When the WTRU is in Mode 2, the WTRU may be configured or instructed to perform one of the resource selection schemes. Additionally, when the WTRU activates, triggers, or uses CSI feedback for sidelink transmission (e.g., for unicast traffic), the WTRU may perform a first resource selection scheme. Additionally, when the WTRU does not have CSI information for one or more subchannels in a resource pool for Mode 2 transmission, the WTRU may perform a second resource selection scheme.

[0211] The second resource selection scheme may be used based on one or more of the following seven conditions, otherwise the first resource selection scheme may be used: (1) if CSI feedback is configured for a sidelink scheme; (2) if CSI information is available for all subchannels; (3) if CSI information is available for at least N subchannels, where N may be configured, indicated, or determined based on the total number of subchannels; (4) if QoS is above a threshold; (5) if the WTRU is within the MCR (e.g., within the minimum communication range); (6) if retransmission is required; and (7) if the CBR is below (or above) a threshold.

[0212] In another example, one or more subchannels may be in a resource pool and the WTRU may determine which subchannel to use for sidelink transmission based on one or more of the following parameters: availability of CSI information, validity of CSI information, RSRP of the subchannel, reception of CSI, subchannel reserved by another WTRU, subchannel with PSFCH resources, or CQI / RI value of the subchannel. Some of the above parameters are described in detail below.

[0213] Parameters regarding the availability of CSI information are described herein. Examples involving CSI information may include CQI, PMI, and / or RI. In addition, one or more subchannels in a resource pool may or may not have CSI information. For example, a transmitting WTRU may trigger a CSI report for a subset of subchannels where a PSSCH may be transmitted, and when the WTRU determines one or more subchannels for sidelink transmission, other subchannels may not have CSI. In addition, subchannels with CSI information may have a higher priority than subchannels without CSI information. For example, if one or more subchannels are candidates for resource selection, subchannels with CSI information may be considered to have a higher priority than subchannels without CSI information.

[0214] Parameters regarding the validity of CSI information are described herein. If CSI is received after a time threshold, the CSI may be considered outdated and the WTRU may consider (or assume) that the CSI is invalid. Therefore, the same priority as a subchannel without CSI may be used or assumed. In addition, for resource selection, a subchannel with CSI received after a time threshold may have a lower priority (or a higher priority) than a subchannel with CSI received before the time threshold. In addition, the time gap between CSI reception and resource selection may be referred to as a CSI validity gap (CVG), and the CSI received for a subchannel with a longer CVG may not be as accurate as the CSI received for a subchannel with a shorter CVG. If one or more subchannels have the same priority, a subchannel with a shorter CVG may have a higher priority for resource selection than another subchannel with a longer CVG.

[0215] Parameters regarding RSRP of subchannels are described herein. For example, the WTRU may measure the RSRP of one or more subchannels in a resource pool and select a first subset of subchannels where the RSRP may be below a threshold (e.g., a threshold corresponding to -10 dBm). The WTRU may then determine a second subset of subchannels from the first subset of subchannels based on the availability of CSI for each subchannel and / or the CVG for each subchannel. If there is still more than one subchannel in the second subset of subchannels, the WTRU may randomly determine which subchannel in the second subset of subchannels to use for sidelink transmission.

[0216] Parameters regarding the reception of SCI are described herein. For example, the WTRU may blindly decode the SCI in each subchannel and if the WTRU receives SCI in a subchannel, the WTRU may exclude the subchannel from the first set of subchannels.

[0217] Parameters regarding a subchannel reserved by another WTRU are described herein. A subchannel may be reserved by another WTRU, and the QoS of the reserved resources may be lower than the QoS of packets that the transmitting WTRU may send on the sidelink. The subchannel resources may be selected for sidelink transmission and are referred to as a reserved subchannel with lower QoS (RSLQ). Additionally, a subchannel without reservation may be referred to as a non-reserved subchannel (NRS). Additionally, in mode 2 resource selection, the RSLQ may have a lower priority (or higher priority) than the NRS. If the RSLQ has CSI information and the NRS does not have CSI information, the RSLQ may have a higher priority than the NRS. In another example, regardless of the valid CSI on the subchannel, the RSLQ may have a lower priority (or higher priority) than the NRS.

[0218] Parameters regarding subchannels with PSFCH resources are described herein. Subchannels with PSFCH resources may have a lower priority than subchannels without PSFCH resources. For example, in a time slot, a first subset of subchannels may have PSFCH resources and a second subset of subchannels may not have PSFCH resources, wherein the second subset of subchannels may have a higher priority than the first subset of subchannels. In one example, the WTRU may first measure the RSRP of one or more subchannels in a resource pool and determine a first subset of subchannels that may have an RSRP below a threshold. The WTRU may then determine a second subset of subchannels that do not have PSFCH resources in the time slot. If the second subset of subchannels has more than one subchannel, the WTRU may randomly select one or more subchannels from the second subset of subchannels for sidelink transmission.

[0219] Parameters regarding CQI / RI values ​​of subchannels are described herein. Subchannel priority may be determined based on the CQI / RI value of each subchannel. A subchannel with a higher CQI / RI value may have a higher priority than a subchannel with a lower CQI / RI value.

[0220] It should be noted that the terms "first" and "second" used in the above-mentioned first subset of subchannels and the second subset of subchannels are only used for the purpose of distinguishing the two subsets of subchannels from each other, and therefore they are not intended to limit the present disclosure. For example, the first subset of subchannels can be used as the second subset of subchannels, and the second subset of subchannels can be used as the first subset of subchannels, and still be consistent with the examples and embodiments provided herein.

[0221] Examples including subchannel sensing are described herein. In one example, the WTRU may perform sensing on a subchannel with valid CSI information, and the WTRU may skip performing sensing on a subchannel without valid CSI, wherein the valid CSI information may include one or more of the following parameters: associated CSI, CSI received less than x time slots earlier, or CQI / RI value above a threshold. Some of the above parameters are described in detail below. The associated CSI may be, for example, a CQI, a PMI, and / or a RI. In addition, examples involving CSI received less than x time slots earlier may include the WTRU performing sensing. For example, if the WTRU performs sensing in time slot #n of a subchannel, CSI for the subchannel may be received after time slot #nx. In addition, x may be determined based on one or more of these parameters: mobility; QoS (e.g., latency requirements); or transmission broadcast type (e.g., groupcast or unicast).

[0222] Examples of sidelink CSI reporting are included herein. A receiving WTRU may report CSI corresponding to a received CSI-RS based on one or more of the following parameters: (1) a CSI request indicated in an SCI associated with a CSI-RS transmission; (2) the presence of CSI indicated in an SCI associated with a CSI RS transmission; (3) a CBR; or (4) an MCR. Some of the above parameters are further described below.

[0223] For example, when a receiving WTRU receives an SCI indicating the presence of a CSI-RS but without a CSI request, the receiving WTRU may measure CSI based on the indicated CSI-RS and store the measurement results but not report the CSI. In another example, the presence of CSI may be indicated in the SCI associated with the CSI-RS transmission. In another example, when the receiving WTRU measures an out-of-range CQI value, the receiving WTRU may send CQI when the CBR is below a threshold. Otherwise, the receiving WTRU may not send CQI. In addition, for example, when the receiving WTRU is outside the MCR, the receiving WTRU may not send a CSI report.

[0224] The following will refer to Figure 3 Describes the CSI reporting time window. Figure 3 is a timing diagram showing an example of a CSI reporting time window. Figure 3 As shown, the receiving WTRU may be required to report CSI triggered by the transmitting WTRU within a time window, where the time window may start at time slot #n+k1 and end at time slot #n+k2 when the CSI report is triggered at time slot #n. The time window here may be referred to as a CSI reporting time window (CSI-TW). One or more of the following examples may apply.

[0225] For example, k1 and k2 may be non-negative integers, ie, k1 ≥ 0, k2 ≥ 0. In addition, each of k1 and k2 may be a predefined number (eg, k1 = 4).

[0226] In another example, k1 may be determined based on the processing capabilities of the WTRUs. For example, a first WTRU may have greater processing capabilities such that it may process faster (e.g., k1=2), while a second WTRU may have less processing capabilities such that it may not process fast enough (e.g., k1=4). The processing capabilities (e.g., k1 value) may be indicated via PC5-RRC during RRC connection establishment.

[0227] In another example, k2 may be determined as a function of k1. For example, k2=k1+Xk, where Xk may be determined based on one or more of the following parameters: (1) one or more of the QoS parameters, (2) CBR, (3) MCR, (4) coverage, (5) mode, (6) broadcast type, or (7) maximum rank. Some of the above parameters are described below. In one example, if the CBR is less than a threshold, the first Xk may be used. Otherwise, the second Xk may be used. The first Xk may be less than the second Xk. In an example using MCR, inside and / or outside the MCR may be used. In an example using coverage, inside or outside the coverage may be used. In an example using a mode, mode 1, mode 2, or both may be used. In an example using a transmission broadcast type, multicast, unicast, or both may be used.

[0228] In another example, k1 may be determined as a function of one or more of the following parameters: (1) the number of subchannels, (2) the number of CSI processes, or (3) the configured CSI feedback. For example, the number of subchannels may be the total number of subchannels in the pool. In one example, the number of subchannels may be the number of subchannels that have been allocated for CSI-RS transmission. In one example, the number of subchannels may be the number of subchannels used for PSSCH transmission.

[0229] In the example including the number of CSI processes, a CSI process may be a CSI measurement for a CSI-RS transmission. A WTRU may be requested to measure more than one CSI-RS at a time, for example from the same WTRU or different WTRUs. Thus, there may be multiple CSI processes.

[0230] In examples including configured CSI feedback, a set of CSI feedback types may be used. For example, different subsets of CSI feedback types (eg, CQI, PMI, RI, L1-RSRP, etc.) may be configured.

[0231] In another example, k1 and / or k2 may be indicated in the associated SCI for CSI feedback triggering. In addition, k1 and / or k2 may be determined based on one or more of the following parameters: one or more of the QoS parameters, CBR, MCR (e.g., within MCR or outside MCR), coverage (e.g., within coverage or outside coverage), mode (mode 1 or mode 2), transmission broadcast type (e.g., multicast or unicast); and / or maximum rank.

[0232] In one example, when the receiving WTRU may not be able to report the triggered CSI within the time window (e.g., between time slot #n+k1 and time slot #n+k2), at least one of the following events may occur: (1) the receiving WTRU may discard the triggered CSI report; (2) the receiving WTRU may indicate to the transmitting WTRU that the previously triggered CSI report has been discarded; or (3) if the QoS of the traffic is above a threshold, the receiving WTRU may increase the k2 value.

[0233]

[00136] A CSI reporting trigger with a reporting time window is described below. In one example, a transmitting WTRU may be allowed to trigger a receiving WTRU to perform up to N sidelink CSI reports within a time window. The time window may be a CSI reporting time window (CSI-TW). The number N may be determined based on one or more of the following examples.

[0234] In one example, N may be the same as the number of slots within the CSI-TW.

[0235] In one example, N=1 may be true for the same subchannel. For example, a transmitting WTRU may trigger a single CSI report for a subchannel within a time window. A receiving WTRU may not wish to receive a CSI report trigger for the same subchannel more than once within a time window. In addition, if a receiving WTRU receives multiple CSI report triggers for the same subchannel within a time window, the receiving WTRU may ignore the report trigger, or the WTRU may only report a single CSI report for one or more CSI report triggers.

[0236] In one example, N may be predetermined or configured. In one example, N may be determined based on a time window length or a number of time slots within a time window.

[0237] In another example, a time window may be configured, determined, or used to trigger a CSI report and / or a CSI-RS transmission. In each time window, the WTRU may trigger a single CSI report and / or CSI-RS transmission.

[0238] The time window may be used or determined according to one or more subchannels (or a group of subchannels). Therefore, if a transmitting WTRU triggers a receiving WTRU to report CSI on a subchannel, the transmitting WTRU may not be allowed to trigger the same receiving WTRU to report CSI on the same subchannel within the time window. However, the transmitting WTRU may trigger the same receiving WTRU to report another CSI on a different subchannel. Alternatively, the transmitting WTRU may trigger a different receiving WTRU to report another CSI on the same subchannel within the time window.

[0239] The time window may be determined or configured per resource pool, WTRU, and / or mode of operation (e.g., Mode 1, Mode 2). In addition, the time window may be determined based on one or more of the following parameters: one or more of the QoS parameters, CBR, MCR (e.g., inside MCR or outside MCR), coverage (e.g., inside coverage or outside coverage), mode (Mode 1 or Mode 2), transmission broadcast type (e.g., multicast or unicast), maximum rank, and / or mobile speed (which may be viewed as a relative speed between two WTRUs). In addition, the time window may be determined based on the number of time slots available for sidelink transmission.

[0240] The discarding of triggered CSI reports is described below. In one example, when one or more subsequent events occur, the receiving WTRU may discard the triggered CSI report.

[0241] In the first event, the receiving WTRU may discard one or more received CSI report triggers if the number of CSI reports triggered within a time window is greater than Z, where Z may be determined based on one or more of the following parameters: WTRU capability, CBR range or CBR of a resource pool, coverage range (in coverage or out of coverage), or operating mode.

[0242] In the second event, the receiving WTRU may determine which CSI report to discard based on one or more of the following parameters: the most recent CSI report trigger, the CSI with the lowest CQI value, QoS, CBR and / or MCR of the associated PSSCH that may include the CSI-RS, the mode or broadcast type of the associated PSSCH that may include the CSI-RS, or the maximum rank or mobile speed.

[0243] In the third event, when the WTRU triggers a CSI report, the transmitting WTRU may indicate a priority level for the CSI report. This priority level may be indicated separately from the priority level of the PSSCH transmission. If a CSI report is triggered, the receiving WTRU may determine whether to discard the CSI report based on the priority level of the CSI report.

[0244] The CSI reporting on the PSSCH is described below. In one example, the receiving WTRU may send CSI reporting bits multiplexed with the PSSCH transmission. The receiving WTRU may determine the resource allocation and coding rate of the CSI reporting bits based on the QoS requirements associated with the CSI-RS transmission, the PSSCH transmission MCS, the PSSCH DMRS configuration and / or the estimated path loss between the transmitting WTRU and the receiving WTRU. In one example, the QoS requirements associated with the CSI-RS transmission may be indicated in the SCI of the CSI-RS transmission. In one example, the QoS requirements associated with the CSI-RS transmission may be the same as the PSSCH transmission accompanying the CSI-RS transmission. In one example, the QoS requirements associated with the CSI-RS transmission may be indicated in the density and / or resource allocation of the CSI-RS transmission.

[0245] The receiving WTRU may indicate the presence of a CSI report in a PSSCH transmission in the SCI. In one example, the receiving WTRU may send a CSI report in the PSSCH without user data. Since the CSI report has a small payload, the receiving WTRU may use a resource subset of the PSSCH resources, such as subchannels and / or symbols. The receiving WTRU may indicate the resource allocation using the subchannel in the SCI associated with the PSSCH transmission. The selection of such a resource subset may be based on the CSI-RS and its accompanying PSSCH transmission resources (e.g., CSI-RS and / or PSCCH subchannel number, timeslot number and / or WTRU L1 ID information).

[0246] The multiplexing of multiple CSI reports is described below. Figure 4 is a timing diagram illustrating an example of multiplexing multiple CSI reports. The receiving WTRU may receive one or more CSI reporting triggers, and the receiving WTRU may be required to report more than one CSI report at a time. The receiving WTRU may receive multiple CSI reporting triggers in succession, and the CSI reporting time windows may overlap, such as Figure 4 As shown in the example in . During overlapping time windows, a receiving WTRU may report more than one CSI report. In addition, a receiving WTRU may receive CSI reports from more than one transmitting WTRU, and the CSI reporting time windows may overlap completely or partially.

[0247] In one example, one or more CSI reports may be multiplexed on a PSCCH transmission. For example, one or more CSI reports may be concatenated with a CSI report index as a payload. One or more CSI reports may be concatenated if the one or more CSI reports are targeted to the same WTRU (e.g., the same transmitting WTRU).

[0248] Figure 5is a timing diagram showing an example of multiplexing CSI reporting with CSI reporting index. Figure 5 As shown, the payload may include one or more CSI information, and each CSI information may include a CSI report index. The multiplexed CSI report may be transmitted or reported by the receiving WTRU on the PSSCH / PSCCH.

[0249] The CSI report index may be indicated based on at least one of the following: (1) the index may be included in the associated SCI; and (2) the index may be determined based on one or more of the following parameters: the timeslot or subframe index in which the CSI report is triggered, the subchannel index, the source ID, or the destination ID. In an example, the subchannel with the subchannel index may include the associated PSCCH / PSSCH. In addition, if more than one subchannel is used, the first or last subchannel in the subchannel set may be used.

[0250] In one example, one or more CSI reports may be multiplexed within a subchannel, where a subchannel may have one or more resource blocks (RBs) and OFDM symbols. In one example, FDM of the CSI reports may be performed. In one example, one or more CSI reports may be multiplexed in different frequency resources. For example, a first CSI report may be transmitted in a first RB within a subchannel, and a second CSI report may be transmitted in a second RB within the subchannel. In another example, a first group of RBs may be used for a first CSI report, and a second group of RBs may be used for a second CSI report.

[0251] In one example, TDM of CSI reports may be performed. For example, one or more CSI reports may be multiplexed in different OFDM symbols.

[0252] In one example, both FDM and TDM of CSI reports may be performed. For example, one or more CSI reports may be multiplexed in different RBs and OFDM symbols.

[0253] The associated time / frequency resources within the subchannel used for CSI reporting (eg, CSI reporting index) may be determined based on the CSI reporting index, source id and / or destination id, and / or subchannel index.

[0254] In another example, if multiple CSI reports are triggered for the same subchannel, the WTRU may report the latest CSI report trigger. Otherwise, the WTRU may multiplex one or more CSI report triggers and report if multiple CSI reports are triggered for different subchannels.

[0255] If one or more CSI reports are triggered on the same subchannel, the WTRU may report the latest CSI trigger. If one or more CSI reports are triggered on different subchannels, the WTRU may report multiplexed CSI reports. If one or more CSI reports are triggered on different subchannels, the WTRU may report CSI reports at different times.

[0256] Examples provided herein may include prioritization of CSI reports and other transmissions. The WTRU may need to transmit one or more sidelink transmissions in a timeslot, where the WTRU may transmit a subset of sidelink transmissions. Each sidelink transmission may be at least one of PSCCH / PSSCH, PSFCH, S-SSB, and / or PSBCH.

[0257] In one embodiment, if one or more sidelink transmissions are based on PSCCH / PSSCH, the first PSSCH may have a higher priority than the second PSSCH.

[0258] In one example, the first PSSCH may be a PSSCH that includes both CSI from higher layers and sidelink packets, and the second PSSCH may be a PSSCH that includes only CSI from higher layers (i.e., does not include sidelink packets). The PSSCH that includes only CSI may have a lower priority than the PSSCH that includes both CSI and sidelink packets (i.e., the second PSSCH may have a lower priority than the first PSSCH). If the WTRU needs to drop one or more sidelink transmissions, the PSSCH with the lower priority may be dropped.

[0259] In one example, the first PSSCH may be a PSSCH that includes both CSI and sidelink packets from a higher layer, and the second PSSCH may be a PSSCH that includes only sidelink packets from a higher layer (i.e., does not include CSI). The PSSCH that includes both CSI and sidelink packets may have a higher priority than the PSSCH that includes only sidelink packets (i.e., the second PSSCH may have a lower priority than the first PSSCH). If the WTRU needs to drop one or more sidelink transmissions, the PSSCH with the lower priority may be dropped.

[0260] In one example, the first PSSCH may be a PSSCH that includes only sidelink packets from a higher layer (i.e., does not include CSI), and the second PSSCH may be a PSSCH that includes only CSI from a higher layer (i.e., does not include sidelink packets). The PSSCH that includes only CSI may have a lower priority than the PSSCH that includes only sidelink packets (i.e., the second PSSCH may have a lower priority than the first PSSCH). If the WTRU needs to drop one or more sidelink transmissions, the PSSCH with the lower priority may be dropped.

[0261] In another example, if one or more sidelink transmissions are based on a PSSCH that includes only CSI, the priority of one or more PSSCHs may be determined based on one or both of the following two methods. First, a PSSCH that includes CSI only for higher QoS (e.g., priority level) may have a higher priority than a PSSCH that includes CSI only for lower QoS (e.g., priority level). The QoS may be the QoS of the PSSCH transmitted together with the CSI-RS for CSI reporting. In addition, the QoS may be indicated in the SCI that may trigger the CSI report. Second, CSI with higher CQI / RI may have a higher priority.

[0262] Although features and elements are described above in specific combinations, it will be understood by those of ordinary skill in the art that each feature or element may be used alone or in any combination with 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 via a wired or wireless connection) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, read-only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media (such as built-in hard disks and removable disks), magneto-optical media, and optical media (such as CD-ROM disks and digital versatile disks (DVDs)). A processor associated with software may be used to implement a radio frequency transceiver for a WTRU, UE, terminal, base station, RNC, or any host computer.

Claims

1. A method for a wireless transmit / receive unit (WTRU), the WTRU being configured as a communication side link (SL) and being configured with a scheduling request (SR) configuration set, the method comprising: receiving, through the SL, a channel state information (CSI) report request for requesting a CSI report and CSI report delay information for the CSI report; Starting a timer based on the received CSI report delay information; Triggering SR transmission specific to CSI reporting; as well as determining whether a SL grant has been received before the timer expires, wherein On the condition that the SL grant has been received before the timer expires, the method further comprises sending the CSI report based on the SL grant; as well as In case no SL grant has been received before expiration of the timer, the method further comprises discarding the CSI report.

2. The method according to claim 1, wherein: Triggering SR transmission includes: selecting an SR configuration from the SR configuration set based on the received CSI report delay information; and An SR is sent to the network based on the SR configuration.

3. The method according to claim 1, wherein: Each of the SR configuration sets is associated with preconfigured CS reporting delay information from a preconfigured CSI reporting delay information set.

4. The method according to claim 3, wherein: The SR configuration is selected under the condition that a delay in the received CSI report delay information falls within a delay range in the preconfigured CSI report delay information.

5. The method according to claim 3, wherein: The WTRU is configured with a mapping of the SR configuration set to the pre-configured CSI reporting delay information set.

6. The method according to claim 1, wherein: The received CSI reporting delay information includes a CSI reporting delay bound.

7. The method according to claim 1, wherein: The CSI report is sent using the SL resources indicated in the SL grant.

8. The method according to claim 1, wherein the method further comprises: The calculated delay for the CSI report is provided to the network.

9. The method according to claim 8, wherein: The calculated delay is sent via the SR transmission or a control message.

10. The method according to claim 8, wherein: The calculated delay may be provided with a physical uplink control channel resource associated with the calculated delay.

11. A wireless transmit / receive unit (WTRU) configured to communicate via a side link (SL) and configured with a scheduling request (SR) configuration set, the WTRU comprising: a transceiver configured to receive, through the SL, (1) a channel state information (CSI) report request requesting a CSI report and (2) CSI report delay information for the CSI report; A processor configured to start a timer based on the received CSI report delay information; Triggering SR transmission specific to CSI reporting; as well as determining whether a SL authorization has been received before the expiration of the time, wherein On the condition that the SL grant is received before the timer expires, the processor is further configured to send the CSI report through the transceiver based on the SL grant; as well as In case no SL grant has been received before expiration of the timer, the processor is further configured to discard the CSI report.

12. The WTRU of claim 11 wherein: To trigger SR transmission, the processor is configured to: selecting an SR configuration from the SR configuration set based on the received CSI report delay information; and Based on the SR configuration, an SR is sent to a network through the transceiver.

13. The WTRU of claim 12, wherein: Each of the SR configuration sets is associated with preconfigured CS reporting delay information from a preconfigured CSI reporting delay information set.

14. The WTRU of claim 13 wherein: The SR configuration is selected under the condition that a delay in the received CSI report delay information falls within a delay range in the preconfigured CSI report delay information.

15. The WTRU of claim 13 wherein: The WTRU is configured with a mapping of the SR configuration set to the pre-configured CSI reporting delay information set.

16. The WTRU of claim 11 wherein: The received CSI reporting delay information includes a CSI reporting delay bound.

17. The WTRU of claim 11 wherein: The CSI report is sent using the SL resources indicated in the SL grant.

18. The WTRU of claim 11 , wherein the processor is further configured to: The calculated delay for the CSI report is sent to a network by the transceiver.

19. The WTRU of claim 18 wherein: The calculated delay is sent via the SR transmission or a control message.

20. The WTRU of claim 18 wherein: The calculated delay may be provided with a physical uplink control channel resource associated with the calculated delay.

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