Apparatus and method for acquiring channel state information of new radio sidelinks

Abstract

This invention discloses a method for use 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 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 a CSI report-specific SR transmission; and determining whether an SL authorization has been received before the timer expires, wherein if an SL authorization has been received before the timer expires, the method further includes 205 transmitting the CSI report based on the SL authorization; and if no SL authorization has been received before the timer expires, the method further includes 206 discarding the CSI report.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of U.S. Provisional Application No. 62 / 886,740, filed August 14, 2019; U.S. Provisional Application No. 62 / 930,970, filed November 5, 2019; and U.S. Provisional Application No. 62 / 975,497, filed February 12, 2020, the contents of which are incorporated herein by reference. Background Technology

[0003] Vehicle-to-Everything (V2X) communication architectures have been developed for wireless communication systems, including those using the Evolved Packet Core (EPC). V2X communication may include one or more of vehicle-to-vehicle (V2V) communication, vehicle-to-pedestrian (V2P) communication, vehicle-to-infrastructure (V2I) communication, and vehicle-to-network (V2N) communication.

[0004] New Radio (NR) V2X supports two operating modes: Mode 1 and Mode 2. Mode 1 operates based on LTE V2X Mode 3. For example, the network can schedule sidelink (SL) resources via downlink (DL) control information (DCI) signaling, and the radio transmit / receive unit (WTRU) can apply the received resource reservations to SL transmissions. Mode 2 can use LTE Mode 4 as a baseline for semi-persistent scheduling. In Mode 4, the WTRU can autonomously select and reserve resources from a configured resource pool. In one example, the configured resource pool can be a pre-configured resource pool. Autonomous resource reservation can be based on WTRU sensing to identify available candidate resources. Summary of the Invention

[0005] This invention discloses a method for use 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 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 a CSI report-specific SR transmission; and determining whether an SL authorization has been received before the timer expires, wherein if an SL authorization has been received before the timer expires, the method further includes 205 transmitting the CSI report based on the SL authorization; and if no SL authorization has been received before the timer expires, the method further includes 206 discarding the CSI report.

[0006] This invention discloses a Wireless Transmit / Receive Unit (WTRU). The WTRU is capable of communicating with a network via a side link (SL), and is configured with a scheduling request (SR) configuration set. The WTRU includes: a transceiver configured to receive (1) a CSI report request requesting a CSI report and (2) CSI report delay information via the SL; a processor configured to: start a timer based on the received CSI report delay information; and trigger a CSI report-specific SR transmission; determine whether an SL authorization has been received before the timer expires, wherein if an SL authorization has been received before the timer expires, the processor is further configured to transmit the CSI report via the transceiver based on the SL authorization; and if no SL authorization has been received before the timer expires, the processor is further configured to discard the CSI report. Attached Figure Description

[0007] A more detailed understanding can be obtained from the following description given by way of example in conjunction with the accompanying drawings, wherein similar reference numerals in the drawings indicate similar elements, and wherein:

[0008] Figure 1A This is a system diagram illustrating an exemplary communication system that can be implemented in one or more of the disclosed embodiments;

[0009] Figure 1B This illustrates that, according to one implementation scheme, it is possible to Figure 1A A system diagram of an exemplary wireless transmit / receive unit (WTRU) used within the communication system shown;

[0010] Figure 1C This illustrates that, according to one implementation scheme, it is possible to Figure 1A A system diagram of an exemplary radio access network (RAN) and an exemplary core network (CN) used within the communication system shown;

[0011] Figure 1D This illustrates that, according to one implementation scheme, it is possible to Figure 1A A system diagram of another exemplary RAN and another exemplary CN used in the communication system shown;

[0012] Figure 2 This is a flowchart illustrating a method according to an embodiment of the present disclosure;

[0013] Figure 3 This is a timing diagram illustrating an example of a Channel State Information (CSI) reporting time window;

[0014] Figure 4 This is a timing diagram illustrating an example of reusing multiple CSI reports; and

[0015] Figure 5This is a timing diagram showing an example of a reused CSI report with a CSI report index. Detailed Implementation

[0016] Figure 1A This is a schematic diagram illustrating an exemplary communication system 100 that can be implemented in one or more of the disclosed embodiments. Communication system 100 can be a multiple access system providing content such as voice, data, video, messaging, and broadcasting to multiple wireless users. Communication system 100 enables multiple wireless users to access such content through the sharing of system resources (including wireless bandwidth). For example, 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 Extended OFDM (ZT-UW-DFT-S-OFDM), Unique Word OFDM (UW-OFDM), Resource Block Filtered OFDM, Filter Bank Multicarrier (FBMC), etc.

[0017] like Figure 1A As 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. However, 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, and 102d can be any type of device configured to operate and / or communicate in a wireless environment. As an example, WTRUs 102a, 102b, 102c, and 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), mobile stations, fixed or mobile user units, subscription-based units, pagers, cellular phones, personal digital assistants (PDAs), smartphones, laptops, netbooks, personal computers, wireless sensors, hotspots or Mi-Fi devices, Internet of Things (IoT) devices, watches or other wearable devices, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in industrial and / or automated processing chain environments), consumer electronics devices, devices operating on commercial and / or industrial wireless networks, etc. Any of WTRUs 102a, 102b, 102c, and 102d may be interchangeably referred to as a UE.

[0018] The communication system 100 may also include base station 114a and / or base station 114b. Each of base stations 114a and 114b may be any type of device configured to wirelessly interface with at least one of WTRUs 102a, 102b, 102c, and 102d to facilitate access to one or more communication networks, such as CN 106, Internet 110, and / or other networks 112. As examples, base stations 114a and 114b may be base transceiver stations (BTS), NodeBs, evolved Node Bs (eNBs), home Node Bs, home evolved Node Bs, next-generation NodeBs such as gNode Bs (gNBs), new radio (NR) NodeBs, site controllers, access points (APs), wireless routers, etc. Although base stations 114a and 114b are each depicted as a single element, it should be understood that base stations 114a and 114b may include any number of interconnected base stations and / or network elements.

[0019] Base station 114a may be part of RAN 104, which may also include other base stations and / or network elements (not shown), such as base station controllers (BSCs), radio network controllers (RNCs), relay nodes, etc. Base station 114a and / or base station 114b may be configured to transmit and / or receive radio signals on one or more carrier frequencies, which may be referred to as cells (not shown). These frequencies may be licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide coverage of radio services to a specific geographic area, which may be relatively fixed or changeable over time. A cell may be further divided into cell sectors. For example, the cell associated with base station 114a may be divided into three sectors. Thus, in one embodiment, base station 114a may include three transceivers, i.e., one transceiver for each sector of the cell. In one embodiment, base station 114a may employ multiple-input multiple-output (MIMO) technology and may utilize multiple transceivers for each sector of the cell. For example, beamforming may be used to transmit and / or receive signals in desired spatial directions.

[0020] Base stations 114a and 114b can communicate with one or more of WTRUs 102a, 102b, 102c, and 102d via air interface 116, which can be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). Any suitable radio access technology (RAT) can be used to establish air interface 116.

[0021] 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, base stations 114a and WTRUs 102a, 102b, and 102c in RAN 104 may implement radio technologies 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).

[0022] In one implementation, base station 114a and WTRUs 102a, 102b, 102c can implement radio technologies such as evolved UMTS terrestrial radio access (E-UTRA), which can use Long Term Evolution (LTE) and / or Advanced LTE (LTE-A) and / or Advanced LTE Pro (LTE-A Pro) to establish air interface 116.

[0023] In one implementation, base station 114a and WTRUs 102a, 102b, 102c can enable radio technologies such as NR radio access, which can use NR to establish air interface 116.

[0024] In one implementation, base station 114a and WTRUs 102a, 102b, and 102c can implement multiple radio access technologies. For example, base station 114a and WTRUs 102a, 102b, and 102c can, for instance, use a dual connectivity (DC) principle to implement both LTE and NR radio access together. Therefore, the air interface utilized by WTRUs 102a, 102b, and 102c can 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).

[0025] In other implementations, base station 114a and WTRUs 102a, 102b, and 102c can implement radio technologies such as IEEE 802.11 (i.e., WiFi), IEEE 802.16 (i.e., WiMAX), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Provisional Standard 2000 (IS-2000), Provisional Standard 95 (IS-95), Provisional Standard 856 (IS-856), Global System for Mobile Communications (GSM), GSM Enhanced Data Rate Evolution (EDGE), and GSM EDGE (GERAN).

[0026] Figure 1A Base station 114b can be, for example, a wireless router, a home node B, a home evolution node B, or an access point, and can utilize any suitable RAT to facilitate wireless connectivity in local areas such as commercial locations, homes, vehicles, campuses, industrial facilities, air corridors (e.g., for use by drones), roads, etc. In one embodiment, base station 114b and WTRUs 102c, 102d can implement radio technologies such as IEEE 802.11 to establish a wireless local area network (WLAN). In one embodiment, base station 114b and WTRUs 102c, 102d can implement radio technologies such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, base station 114b and WTRUs 102c, 102d can utilize cellular-based RATs (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish picocells or femtocells. Figure 1A As shown, base station 114b may have a direct connection to Internet 110. Therefore, base station 114b may not need to access Internet 110 via CN 106.

[0027] RAN 104 can communicate with CN 106, which can be any type of network configured to provide voice, data, application, and / or Voice over Internet Protocol (VoIP) services to one or more of WTRUs 102a, 102b, 102c, and 102d. Data can have different Quality of Service (QoS) requirements, such as different throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. CN 106 can provide call control, billing services, location-based services, prepaid calling, internet connectivity, video distribution, etc., and / or perform advanced security functions such as user authentication. Although not explicitly stated... Figure 1AAs shown, but it should be understood, RAN 104 and / or CN 106 can communicate directly or indirectly with other RANs that use the same RAT as RAN 104 or a different RAT. For example, in addition to being connected to RAN 104 which can utilize NR radio technology, CN 106 can also communicate with another RAN (not shown) that uses GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.

[0028] CN 106 may also act as a gateway for WTRUs 102a, 102b, 102c, and 102d to access PSTN 108, the Internet 110, and / or other networks 112. PSTN 108 may include a circuit-switched telephone network providing Common Old-Style Telephone Service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices using common communication protocols such as Transmission Control Protocol (TCP), User Datagram Protocol (UDP), and / or Internet Protocol (IP) from the TCP / IP Internet Protocol suite. Network 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, network 112 may include another CN connected to one or more RANs, which may use the same RAT as RAN 104 or a different RAT.

[0029] Some or all of the WTRUs 102a, 102b, 102c, and 102d in the communication system 100 may include multi-mode capabilities (e.g., WTRUs 102a, 102b, 102c, and 102d may include multiple transceivers for communicating with different wireless networks via different wireless links). For example, Figure 1A The WTRU 102c shown can be configured to communicate with a base station 114a that can employ cellular-based radio technology and with a base station 114b that can employ IEEE 802 radio technology.

[0030] Figure 1B This is a system diagram illustrating an exemplary WTRU 102. (See diagram below.) Figure 1B As shown, WTRU 102 may include a processor 118, a transceiver 120, a transmitting / receiving element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power supply 134, a Global Positioning System (GPS) chipset 136, and / or other peripheral devices 138, etc. It should be understood that WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with the implementation.

[0031] Processor 118 can be a general-purpose processor, a special-purpose processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), any other type of integrated circuit (IC), a state machine, etc. Processor 118 can perform signal encoding, data processing, power control, input / output processing, and / or any other functions that enable WTRU 102 to operate in a wireless environment. Processor 118 can be coupled to transceiver 120, which can be coupled to transmitting / receiving element 122. Although Figure 1B The processor 118 and transceiver 120 are depicted as separate components, but it should be understood that the processor 118 and transceiver 120 may be integrated together in an electronic package or chip.

[0032] Transmitting / receiving element 122 may be configured to transmit signals to or receive signals from a base station (e.g., base station 114a) via air interface 116. For example, in one embodiment, transmitting / receiving element 122 may be an antenna configured to transmit and / or receive RF signals. In one embodiment, transmitting / receiving 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, transmitting / receiving element 122 may be configured to transmit and / or receive RF and optical signals. It should be understood that transmitting / receiving element 122 may be configured to transmit and / or receive any combination of wireless signals.

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

[0034] Transceiver 120 can be configured to modulate signals transmitted by transmitting / receiving element 122 and demodulate signals received by transmitting / receiving element 122. As noted above, WTRU 102 may have multi-mode capability. Therefore, transceiver 120 may include multiple transceivers to enable WTRU 102 to communicate via various RATs (such as NR and IEEE 802.11).

[0035] The processor 118 of 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) 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, keypad 126, and / or display / touchpad 128. Furthermore, the processor 118 may access information from any type of suitable memory (such as non-removable memory 130 and / or removable memory 132) and store data in any type of suitable memory. Non-removable memory 130 may include random access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. Removable memory 132 may include a user identity module (SIM) card, memory stick, secure digital storage (SD) card, etc. In other embodiments, the processor 118 may access information from memory that is not physically located on WTRU 102 (such as on a server or home computer (not shown)) and store data in that memory.

[0036] The processor 118 may receive power from the power supply 134 and may be configured to distribute and / or control power to other components in the WTRU 102. The power supply 134 may be any suitable device for powering the WTRU 102. For example, the power supply 134 may include one or more dry cell battery packs (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0037] The processor 118 may also be coupled to a GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) about the current location of the WTRU 102. In addition to or instead of the information from the GPS chipset 136, the WTRU 102 may receive location information from base stations (e.g., base stations 114a, 114b) via air interface 116 and / or determine its location based on the timing of signals received from two or more nearby base stations. It should be understood that, while remaining consistent with the implementation, the WTRU 102 may acquire location information using any suitable location determination method.

[0038] The processor 118 may also be coupled to other peripheral devices 138, which may include one or more software and / or hardware modules providing additional features, functions, and / or wired or wireless connectivity. For example, peripheral device 138 may include an accelerometer, electronic compass, satellite transceiver, digital camera (for photos and / or video), Universal Serial Bus (USB) port, vibration device, television transceiver, hands-free headset, etc. Modules, FM radio units, digital music players, media players, video game player modules, internet browsers, virtual reality and / or augmented reality (VR / AR) devices, activity trackers, etc. Peripheral devices 138 may include one or more sensors. Sensors may be one or more of the following: gyroscopes, accelerometers, Hall effect sensors, magnetometers, orientation sensors, proximity sensors, temperature sensors, time sensors; geolocation sensors, altimeters, light sensors, touch sensors, magnetometers, barometers, gesture sensors, biometric sensors, humidity sensors, etc.

[0039] WTRU 102 may include a full-duplex radio for which the 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 through signal processing via hardware (e.g., a choke) or via a processor (e.g., a separate processor (not shown) or via processor 118). In one embodiment, WTRU 102 may include a half-duplex radio for which the 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)) are concurrent.

[0040] Figure 1C This is a system diagram illustrating RAN 104 and CN 106 according to one embodiment. As described above, RAN 104 can communicate with WTRUs 102a, 102b, and 102c via air interface 116 using E-UTRA radio technology. RAN 104 can also communicate with CN 106.

[0041] RAN 104 may include evolved Nodes B 160a, 160b, and 160c; however, it should be understood that RAN 104 may include any number of evolved Nodes B while remaining consistent with the implementation scheme. Evolved Nodes B 160a, 160b, and 160c may each include one or more transceivers for communicating with WTRUs 102a, 102b, and 102c via air interface 116. In one implementation, evolved Nodes B 160a, 160b, and 160c may implement MIMO technology. Therefore, evolved Node B 160a may, for example, use multiple antennas to transmit radio signals to and / or receive radio signals from WTRU 102a.

[0042] Each of the evolved nodes B 160a, 160b, and 160c can be associated with a specific cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, and user scheduling in the UL and / or DL, etc. Figure 1C As shown, evolution nodes B 160a, 160b, and 160c can communicate with each other via the X2 interface.

[0043] Figure 1C The CN 106 shown 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.

[0044] The MME 162 can connect to each of the evolved nodes B 162a, 162b, and 162c in RAN 104 via the S1 interface and can be used as a control node. For example, the MME 162 can be responsible for authenticating users of WTRUs 102a, 102b, and 102c, bearer activation / deactivation, selecting a specific serving gateway during the initial attachment of WTRUs 102a, 102b, and 102c, etc. The MME 162 can provide control plane functions for handover between RAN 104 and other RANs (not shown) employing other radio technologies such as GSM and / or WCDMA.

[0045] The SGW 164 can connect to each of the evolved Nodes B 160a, 160b, and 160c in RAN 104 via the S1 interface. The SGW 164 typically routes and forwards user data packets to and from WTRUs 102a, 102b, and 102c. The SGW 164 can perform other functions such as anchoring the user plane during inter-evolved Node B handovers, triggering paging when DL data is available for WTRUs 102a, 102b, and 102c, and managing and storing the context of WTRUs 102a, 102b, and 102c.

[0046] SGW 164 can be connected to PGW 166, which provides WTRU 102a, 102b, 102c with access to packet-switched networks (such as Internet 110) to facilitate communication between WTRU 102a, 102b, 102c and IP-enabled devices.

[0047] CN 106 can facilitate communication with other networks. For example, CN 106 can provide WTRUs 102a, 102b, and 102c with access to a circuit-switched network (such as PSTN 108) to facilitate communication between WTRUs 102a, 102b, and 102c and conventional landline communication equipment. For example, CN 106 may include an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between CN 106 and PSTN 108, or be able to communicate with such an IP gateway. Additionally, CN 106 can provide WTRUs 102a, 102b, and 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0048] Despite WTRU in Figures 1A to 1D While described as a wireless terminal, it is conceivable that in some representative implementations, such a terminal may (e.g., temporarily or permanently) use a wired communication interface with a communication network.

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

[0050] A WLAN in Infrastructure Basic Services Set (BSS) mode may have an access point (AP) for the BSS and one or more sites (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 out of the BSS. Traffic originating outside the BSS and destined for a STA can reach and be delivered to the STA via the AP. Traffic originating from a STA and destined for a destination outside the BSS can be sent to the AP for delivery to the appropriate destination. Traffic between STAs within the BSS can be sent via the AP, for example, where a source STA can send traffic to the AP, and the AP can deliver the traffic to the destination STA. Traffic between STAs within the BSS can be considered and / or referred to as point-to-point traffic. Point-to-point traffic can be sent between source and destination STAs (e.g., directly between them) using Direct Link Establishment (DLS). In some representative implementations, the DLS may use 802.11e DLS or 802.11z Tunneled DLS (TDLS). WLANs using the Standalone BSS (IBSS) mode may not have an access point (AP), and STAs within the IBSS or using the IBSS (e.g., all STAs) can communicate directly with each other. The IBSS communication mode may sometimes be referred to as the "ad-hoc" communication mode in this document.

[0051] When operating in 802.11ac infrastructure mode or a similar mode, the AP can transmit beacons on a fixed channel, such as the primary channel. The primary channel can be of fixed width (e.g., a 20 MHz bandwidth) or dynamically configured. The primary channel can be the operating channel of the BSS and can be used by the STA to establish a connection with the AP. In some representative implementations, Carrier Sense Multiple Access / Collision Avoidance (CSMA / CA) can be implemented, for example, in an 802.11 system. For CSMA / CA, each STA (including the AP) can listen to the primary channel. If the primary channel is listened to / detected and / or determined to be busy by a particular STA, that STA can back off. A single STA (e.g., only one station) can transmit in a given BSS at any given time.

[0052] High-throughput (HT) STAs can communicate using a 40MHz wide channel, for example, by combining a primary 20MHz channel with adjacent or non-adjacent 20MHz channels to form a 40MHz wide channel.

[0053] The Very High Throughput (VHT) STA supports channels with widths of 20MHz, 40MHz, 80MHz, and / or 160MHz. 40MHz and / or 80MHz channels can be formed by combining consecutive 20MHz channels. A 160MHz channel can be formed by combining eight consecutive 20MHz channels, or by combining two non-consecutive 80MHz channels (this can be referred to as an 80+80 configuration). For the 80+80 configuration, after channel coding, data can be split into two streams by a segment parser. Each stream can be processed individually using Inverse Fast Fourier Transform (IFFT) and time-domain processing. These streams can be mapped to two 80MHz channels, and data can be transmitted via the transmitting STA. At the receiver of the receiving STA, the operations described above for the 80+80 configuration can be reversed, and the combined data can be sent to Media Access Control (MAC).

[0054] 802.11af and 802.11ah support operating modes below 1 GHz. Compared to those used in 802.11n and 802.11ac, 802.11af and 802.11ah reduce channel operating bandwidth and carrier. 802.11af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in the TV white space (TVWS) spectrum, while 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum. According to representative implementations, 802.11ah may support instrument-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 supporting (e.g., only supporting) certain bandwidths and / or limited bandwidths. MTC devices may include batteries with battery life above a threshold (e.g., to maintain a very long battery life).

[0055] WLAN systems supporting 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. A primary channel can have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel can be set and / or limited by STAs operating in the BSS (each supporting a minimum bandwidth operating mode). In the 802.11ah example, for STAs supporting (e.g., only supporting) a 1MHz mode (e.g., MTC type devices), the primary channel can 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 Sense and / or Network Allocation Vector (NAV) settings can depend on the status of the primary channel. If the primary channel is busy, for example, because an STA (supporting only the 1MHz operating mode) is transmitting to the AP, the entire available frequency band can be considered busy even if most of the available bands remain idle.

[0056] In the United States, the available frequency bands for 802.11ah are 902MHz to 928MHz. In South Korea, the available frequency bands are 917.5MHz to 923.5MHz. In Japan, the available frequency bands are 916.5MHz to 927.5MHz. The total available bandwidth for 802.11ah ranges from 6MHz to 26MHz, depending on the country code.

[0057] Figure 1D This is a system diagram illustrating RAN 104 and CN 106 according to one implementation scheme. As noted above, RAN 104 can communicate with WTRU 102a, 102b, and 102c via air interface 116 using NR radio technology. RAN 104 can also communicate with CN 106.

[0058] RAN 104 may include gNBs 180a, 180b, and 180c, but it should be understood that RAN 104 may include any number of gNBs while remaining consistent with the implementation. Each gNB 180a, 180b, and 180c may include one or more transceivers for communication with WTRUs 102a, 102b, and 102c via air interface 116. In one implementation, gNBs 180a, 180b, and 180c may implement MIMO technology. For example, gNBs 180a and 180b may utilize beamforming to transmit signals to and / or receive signals from gNBs 180a, 180b, and 180c. Therefore, gNB 180a may, for example, use multiple antennas to transmit radio signals to and / or receive radio signals from WTRU 102a. In one implementation, gNBs 180a, 180b, and 180c may implement carrier aggregation technology. For example, gNB 180a may transmit multiple component carriers to 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 implementation, gNBs 180a, 180b, and 180c may implement Cooperative Multipoint (CoMP) technology. For example, WTRU 102a may receive cooperative transmissions from gNBs 180a and 180b (and / or gNB 180c).

[0059] WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c using transmissions associated with scalable parameter sets. For example, OFDM symbol spacing and / or OFDM subcarrier spacing can vary depending on different transmissions, different cells, and / or different portions of the radio transmission spectrum. WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c using subframes or transmission time intervals (TTIs) of various or scalable lengths (e.g., containing different numbers of OFDM symbols and / or continuously varying absolute time lengths).

[0060] gNBs 180a, 180b, and 180c can be configured to communicate with WTRUs 102a, 102b, and 102c in standalone and / or non-standalone configurations. In standalone configuration, WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c without accessing other RANs (e.g., evolved Node Bs 160a, 160b, and 160c). In standalone configuration, WTRUs 102a, 102b, and 102c can use one or more of gNBs 180a, 180b, and 180c as mobility anchors. In standalone configuration, WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c using signals in unlicensed frequency bands. In a non-standalone configuration, WTRUs 102a, 102b, and 102c can communicate or connect to gNBs 180a, 180b, and 180c, and also communicate or connect to other RANs (such as eNode-B160a, 160b, and 160c). For example, WTRUs 102a, 102b, and 102c can implement DC principles to communicate substantially simultaneously with one or more gNBs 180a, 180b, and 180c and one or more evolved Node Bs 160a, 160b, and 160c. In a non-standalone configuration, evolved Node Bs 160a, 160b, and 160c can be used as mobility anchors for WTRUs 102a, 102b, and 102c, and gNBs 180a, 180b, and 180c can provide additional coverage and / or throughput for serving WTRUs 102a, 102b, and 102c.

[0061] Each of gNBs 180a, 180b, and 180c can be associated with a specific cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, network slicing support, interoperability between DC, NR, and E-UTRA, routing of user plane data to User Plane Functions (UPF) 184a and 184b, routing of control plane information to Access and Mobility Management Functions (AMF) 182a and 182b, etc. Figure 1D As shown, gNB 180a, 180b, and 180c can communicate with each other via the Xn interface.

[0062] Figure 1D The CN 106 shown may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one Session Management Function (SMF) 183a, 183b, and possibly a Data Network (DN) 185a, 185b. Although the foregoing elements are depicted as part of CN 106, it should be understood that any of these elements may be owned and / or operated by an entity other than a CN operator.

[0063] AMF 182a and 182b can connect to one or more of gNB 180a, 180b, and 180c via the N2 interface in RAN 104 and can be used as control nodes. For example, AMF 182a and 182b can be responsible for authenticating users of WTRU 102a, 102b, and 102c, supporting network slicing (e.g., handling different Protocol Data Unit (PDU) sessions with different requirements), selecting specific SMF 183a and 183b, managing registration areas, terminating Non-Access Stratum (NAS) signaling, mobility management, etc. AMF 182a and 182b can use network slicing to customize CN support for WTRU 102a, 102b, and 102c based on the type of service used by WTRU 102a, 102b, and 102c. For example, different network slices can be established for different use cases, such as services that rely on Ultra-Reliable Low Latency (URLLC) access, services that rely on Enhanced Mobile Broadband (eMBB) access, and services for MTC access. AMF 182a and 182b can provide control plane functions for handover between RAN 104 and other RANs (not shown) that employ other radio technologies, such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies, such as WiFi.

[0064] SMFs 183a and 183b can connect to AMFs 182a and 182b in CN 106 via the N11 interface. SMFs 183a and 183b can also connect to UPFs 184a and 184b in CN 106 via the N4 interface. SMFs 183a and 183b can select and control UPFs 184a and 184b, and configure traffic routing through UPFs 184a and 184b. SMFs 183a and 183b can perform other functions, such as managing and allocating UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, and providing DL data notifications. PDU session types can be IP-based, non-IP-based, Ethernet-based, etc.

[0065] UPF 184a and 184b can connect via the N3 interface to one or more of the gNBs 180a, 180b, and 180c in RAN 104. These gNBs can provide WTRU 102a, 102b, and 102c with access to packet-switched networks (such as Internet 110) to facilitate communication between WTRU 102a, 102b, 102c and IP-enabled devices. UPF 184 and 184b can perform other functions such as routing and forwarding packets, enforcing user plane policies, supporting multihomed PDU sessions, handling user plane QoS, buffering DL packets, and providing mobility anchoring.

[0066] CN 106 may facilitate communication with other networks. For example, CN 106 may include an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between CN 106 and PSTN 108, or may communicate with such an IP gateway. Additionally, CN 106 may provide WTRUs 102a, 102b, and 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, WTRUs 102a, 102b, and 102c may be connected to DNs 185a and 185b via UPFs 184a and 184b through an N3 interface to UPFs 184a and 184b and an N6 interface between UPFs 184a and 184b and local DNs 185a and 185b.

[0067] Given Figures 1A to 1D as well as Figures 1A to 1D The corresponding descriptions herein refer to one or more of the functions described below, which may be performed by one or more emulation 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, UPF 184a-b, SMF 183a-b, DN 185a-b, and / or any other device described herein. An emulation device may be one or more devices configured to mimic one or more of the functions described herein. For example, an emulation device may be used to test other devices and / or simulate network and / or WTRU functions.

[0068] Simulation devices can be designed to perform one or more tests on other devices in laboratory and / or carrier network environments. 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 to test other devices within the communication network. The one or more simulation devices may perform one or more or all functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network. Simulation devices may be directly coupled to another device for testing purposes and / or use over-the-air wireless communication to perform tests.

[0069] The one or more emulation 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 emulation devices may be used in test scenarios within a test laboratory and / or non-deployed (e.g., testing) wired and / or wireless communication networks to perform testing of one or more components. The one or more emulation devices may be test equipment. Direct RF coupling and / or wireless communication via RF circuitry (e.g., which may include one or more antennas) may be used by the emulation devices to transmit and / or receive data.

[0070] LTE vehicle-to-everything (V2X) communication may not support Channel State Information (CSI) acquisition. One reason for this lack of support may be that LTE V2X can be used for broadcast transmissions. NR V2X can support sidelink CSI acquisition for unicast transmissions. Furthermore, NR CSI acquisition may include at least one of the following features: sidelink CSI reporting can be enabled / disabled via configuration; non-periodic CSI reporting; non-subband-based CSI; CSI reference signal (RS) transmission coupled to and confined within the 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 up to 2 ranks; CQI and RI may be reported together; or, CSI reports may be delivered using the PSSCH and its resource allocation procedures.

[0071] NR V2X supports two operating modes: Mode 1 and Mode 2. Mode 1 operates based on LTE V2X Mode 3. For example, the network can schedule sidelink (SL) resources via downlink (DL) control information (DCI) signaling, and the WTRU can apply the received resource reservations to SL transmissions. Mode 2 can use LTE Mode 4 as a baseline for semi-persistent scheduling. In Mode 4, the WTRU can autonomously select and reserve resources from a configured resource pool. In one example, the configured resource pool can be a pre-configured resource pool. Autonomous resource reservation can be based on WTRU sensing to identify available candidate resources. The WTRU can semi-persistently schedule resources with reservation intervals. In other words, the WTRU can reserve the same resources once per reservation interval. Additionally, the WTRU can be configured with a resource reselection counter and triggering conditions, and will reselect resources when the counter expires or the triggering conditions occur. In one example, the WTRU can be pre-configured with a resource reselection counter and triggering conditions.

[0072] Therefore, LTE Mode 4 semi-persistent scheduling is applicable to NR SL periodic traffic. Furthermore, NR V2X can support many advanced use cases based on non-periodic traffic. Additionally, the way Mode 2 operation handles non-periodic traffic and the corresponding resource reservations can vary.

[0073] There may be issues with CSI-RS transmission instances. NR V2X SL may only support CSI-RS transmissions alongside PSSCH transmissions. Therefore, unlike NR Uu CSI-RS transmissions, there are no periodic CSI-RS transmissions available for WTRUs to periodically update CSI under SL. PSSCH transmission instances can be based on traffic patterns, such as the periodicity and burstiness of data. Sending CSI-RS in every data transmission (i.e., every PSSCH transmission) can lead to unnecessary overhead, for example, when there is a large amount of data to transmit in a slow-varying channel. It may also reduce resource utilization efficiency in Mode 2 operation, considering CSI reporting transmissions.

[0074] Furthermore, non-subband CSI based on PSSCH transmission bandwidth may present issues. CSI-RS transmissions may be confined to PSSCH transmissions. Therefore, associated reports may only apply to PSSCH resource allocations in the frequency domain. Since PSSCH resource allocations may be based on data packet size, small packet PSSCH transmissions may occupy one or more subchannels, thus potentially failing to provide accurate non-subband CSI reports.

[0075] In some examples, higher congestion may occur from CSI reports. A sidelink unicast transmit WTRU can trigger aperiodic CSI reports on the sidelink, which can increase congestion in the resource pool because the receive WTRU that is triggered to report a CSI may be required to send a sidelink transmission, even if the receive WTRU may not have any packets to send.

[0076] In other examples, CSI reporting timing may be problematic. In NR V2X, explicit CSI reporting may not be used. Therefore, the transmitting WTRU can wait indefinitely for triggered CSI reports. The receiving WTRU can report triggered CSIs whenever sidelink resources become available. In high-mobility scenarios, delayed CSI feedback may be outdated and useless when the transmitting WTRU receives the CSI report.

[0077] In another example, sidelink resource selection may present issues. In WTRU autonomous resource selection, such as in Mode 2, the WTRU can select one or more sidelink resources based on sensing. During sensing, the WTRU can first select a subset of subchannels based on the decoding of the Reference Signal Received Power (RSRP) / Sidelink Control Information (SCI), and then the WTRU can randomly select one or more subchannels. In one example, the WTRU can select subchannels with RSRP below a threshold. However, the availability of CSI in each subchannel can be disregarded.

[0078] The sidelink transmit WTRU, transmit WTRU, transmitter WTRU, sidelink Tx WTRU, Tx WTRU, and first WTRU are interchangeable and remain consistent with the examples and implementations provided herein. Additionally, the sidelink receive WTRU, receive WTRU, sidelink Rx WTRU, Rx WTRU, receiver WTRU, and second WTRU are interchangeable and remain consistent with the examples and implementations provided herein.

[0079] Furthermore, the sidelink CSI can be used interchangeably with CSI, and remains consistent with the examples and implementations provided herein. Additionally, the sidelink measurement reference signal used for CSI measurements can be referred to as the sidelink CSI reference signal (S-CSI-RS), and is interchangeable with CSI-RS, and remains consistent with the examples and implementations provided herein.

[0080] Furthermore, the 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 are interchangeable and can remain consistent with the examples and embodiments provided herein. Additionally, CSI reports, Sidelink CSI reports, CSI-RS transmissions, Sidelink CSI-RS transmissions, CSI-RS presence indications, and Sidelink CSI-RS presence indications are interchangeable and can remain consistent with the examples and embodiments provided herein.

[0081] Furthermore, the measurement results, RSRP, RSRQ, RSSI, L1-RSRP, and SINR are interchangeable and can still be consistent with the examples and implementations provided herein. Additionally, time slots are interchangeable with subframes, radio frames, logical time slots, sidelink time slots, Uu time slots, time slots, and time slots configured for sidelink transmission, and can still be consistent with the examples and implementations provided herein.

[0082] The CSI report index, CSI report identifier, CSI report process, CSI process, and CSI process identifier are interchangeable and can remain consistent with the examples and implementations provided herein. Furthermore, CSI reports, CSI feedback, and CSI report triggers are interchangeable and can remain consistent with the examples and implementations provided herein.

[0083] In some implementations, a sidelink reference signal for CSI measurement can be used. Sidelink CSI can be measured, estimated, or determined based on the reference signal used for sidelink CSI measurement, wherein the reference signal can be transmitted, signaled, or received on sidelink resources.

[0084] Therefore, different sidelink CSI-RS types can be used. In some examples, one or more of the following may be applicable to sidelink CSI-RS: The transmitting WTRU may transmit CSI-RS on a sidelink resource, where the sidelink resource may be a resource used for PSSCH transmission. The CSI-RS may reside within the used, selected, or determined PSSCH resource. Furthermore, one or more types of CSI-RS may be used.

[0085] The first type of CSI-RS can be a reference signal transmitted for CSI measurements and exists only when CSI feedback is enabled or sidelink measurements are used. For example, radio link modulation (RLM) or radio resource management (RRM) can be used. The first type of CSI-RS can be an RS transmitted separately from the demodulated reference signal (DM-RS) used for the associated sidelink channel (such as PSSCH or Physical Sidelink Control Channel (PSCCH)). The associated sidelink channel can be a sidelink channel that may include an indication of the presence of the CSI-RS, an indication of CSI report triggering, 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).

[0086] The second type of CSI-RS can be a reference signal transmitted due to CSI measurements and is always present in the PSSCH resource, regardless of whether CSI feedback is enabled or disabled. The second type of CSI-RS can be used as a DM-RS for another sidelink channel (e.g., PSCCH or PSSCH). The second type of CSI-RS can be referred to as a DM-RS when not used for CSI measurements. The temporal density of the second type of CSI-RS can be configured or determined based on one or more transmission parameters of the sidelink channel (e.g., PSSCH or PSCCH), where transmission parameters may include at least one of modulation and coding scheme (MCS), transport block size, QoS, or broadcast type.

[0087] 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).

[0088] The location of CSI-RS can 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 can be transmitted in PSSCH resources that can be scheduled by the PSCCH, where the SCI can trigger a CSI report or indicate the presence of the CSI-RS. Furthermore, when the operating frequency is above a threshold (e.g., 6 GHz), the associated CSI-RS can be transmitted in PSSCH resources that can be reserved by the PSCCH, where the SCI can trigger a CSI report or indicate the presence of the CSI-RS.

[0089] This document provides examples of determining the CSI-RS type. 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, the transmitting WTRU may determine which CSI-RS type is available for CSI report triggering. The CSI-RS type may be determined based on one or more of the following implementations. Furthermore, the receiving WTRU may determine which CSI-RS type is available for CSI measurement based on one or more of the following implementations.

[0090] In one implementation, the type of CSI-RS used for CSI measurements can 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), mobility speed, indication in SCI, and DM-RS density. In one example, the determination of CSI measurements can be performed between a first type of CSI-RS and a second type of CSI-RS. That is, in one implementation, either a first type of CSI-RS or a second type of CSI-RS can be determined and thus used for CSI measurements. Some of the parameters described above for determining the type of CSI-RS will be described in detail below.

[0091] 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) can be used. Otherwise, a first type of CSI-RS (e.g., M-CSI-RS) can be used. In one example, the threshold could be 2. Therefore, for example, if the maximum rank of unicast is 1, then DM-RS for PSSCH can be used for CSI measurements. Otherwise, M-CSI-RS can be used.

[0092] In another example, the slot index may relate to the slots used 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) can be used. Otherwise, a second type of CSI-RS (e.g., DM-RS for PSSCH) can be used.

[0093] In another example, subchannel indexing can be used. For instance, one or more subchannels within a resource pool can be configured for a specific purpose. This purpose could include, for example, Physical Side Link Feedback Channel (PSFCH) transmission. A second type of CSI-RS can be used for those subchannels; otherwise, a first type of CSI-RS can be used. For example, when a subchannel includes PSFCH resources, the DM-RS of the PSFCH can be used for CSI measurements.

[0094] In another example, if the CBR is above a threshold, a second type of CSI-RS can be used. Otherwise, a first type of CSI-RS can be used for CSI measurements. For example, the threshold could be 40%.

[0095] Additionally, if the QoS of the unicast link is above a threshold, the first type of CSI-RS can be used. Otherwise, the second type of CSI-RS can be used for CSI measurements. For example, the threshold can be associated with a quantization value between 1 and 8 (3 bits). For example, QoS can be the worst-case or best-case QoS.

[0096] In examples involving the MCR, if the receiving WTRU is within the MCR, then type 1 CSI-RS can be used. Otherwise, type 2 CSI-RS can be used.

[0097] In examples involving movement speed, if the relative speed or WTRU speed is above a threshold, type II CSI-RS can be used. Otherwise, type I CSI-RS can be used. For example, the threshold could be XXXX.

[0098] In an example involving indications in an SCI, when a WTRU triggers a CSI feedback, the WTRU can indicate which type of CSI-RS is used for the CSI feedback in the associated SCI. In one example, the indication can be explicit. In another example, the indication can be implicit.

[0099] In another example, if the DM-RS density of the PSSCH is above a threshold, then type II CSI-RS can be used. Otherwise, type I CSI-RS can be used. For example, the threshold could be XXXX.

[0100] The maximum rank indicator (RI) value can be limited based on the number of antenna ports used for the second type of CSI-RS. The number of antenna ports can be determined based on the transmission rank of the sidelink channel (e.g., PSSCH or PSCCH) of the second type of CSI-RS. In other words, when using the second type of CSI-RS, the maximum RI value can be limited based on the transmission rank of the sidelink channel.

[0101] Depending on the type of CSI-RS used, the rate matching of resource elements (REs) for PSSCH can vary. For example, when using a Type 1 CSI-RS, one or more PSSCH REs that may overlap with a Type 1 CSI-RS can be rate matched. Furthermore, when using a Type 2 CSI-RS, rate matching of PSSCH REs may not be necessary due to the CSI-RS. Alternatively, perforation can be used instead of rate matching for PSSCH REs. For perforated PSSCH REs, the WTRU can transmit a zero-energy signal on the RE or may not transmit any signal on the RE. For rate-matched PSSCH REs, the WTRU may not consider the RE as a usable RE for PSSCH transmission. Furthermore, the transmit / receive WTRU can determine which REs can be perforated or rate matched based on which type of S-CSI-RS is available.

[0102] The determination, selection, or both of rate-matched PSSCH REs and perforated PSSCH REs can also depend on the data QoS. For example, a rate-matched PSSCH RE can be applied for data with high reliability requirements. Otherwise, a perforated PSSCH RE can be applied. The determination, selection, or both of rate-matched PSSCH REs and perforated PSSCH REs can also depend on the data QoS and the type of S-SCI-RS used.

[0103] First, sidelink CSI reporting is described. In some examples, the WTRU can trigger, activate, or deactivate sidelink CSI reporting to determine sidelink channel quality. Triggering sidelink CSI reporting may include one or more of the following implementations.

[0104] The transmitting WTRU can request reports / feedback of measurements of the 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, CSI may include one or more of CQI, PMI, or RI. Furthermore, the request may be received by the receiving WTRU, which may be a WTRU in sidelink communication (e.g., unicast or multicast).

[0105] Additionally, the transmitting WTRU can transmit a measurement RS, which may be at least one of CSI-RS, beam measurement reference signal (BM-RS), demodulation reference signal of PSCCH and / or PSSCH (DM-RS), phase tracking reference signal (PT-RS), radio link modulation reference signal (RLM-RS), or radio resource management reference signal (RRM-RS). The measurement RS may be transmitted in PSSCH resources, wherein the measurement RS may be transmitted when the transmitting WTRU has sidelink data to be transmitted.

[0106] Furthermore, the time / frequency location of the measurement RS within the associated PSSCH resource can be indicated in the associated PSCCH, where the PSSCH resource can be one or more sub-channels within a resource pool. If the associated PSSCH occupies more than one sub-channel, the measurement RS can be transmitted in a subset of the sub-channels. The sub-channel location can be predefined (e.g., first sub-channel, middle sub-channel, or last sub-channel). Additionally, the sub-channel location can be determined based on one or more of the following parameters: identity, QoS, CBR, MCR, and whether it is within or outside coverage. In the example, identity can be source ID, destination ID, or both. Furthermore, the sub-channel location can be configured via PC5-Radio Resource Control (RRC).

[0107] In addition, the transmitting WTRU can send an indication to trigger a sidelink CSI report, where the indication can be at least one of the following parameters: a bit field in the relevant SCI, source=id, or a slot number or index. These parameters will be described in detail below.

[0108] In an example of a related SCI that includes a bit field, the bit field may indicate one or more of the following: the presence of a measured RS, the time / frequency location of a measured RS, the transmission power level (or ratio) of a measured RS, or periodic or non-periodic reporting.

[0109] In one example, the receiving WTRU can receive the SCI from a source ID, which may be pre-configured or predetermined. The receiving WTRU can measure and report the sidelink CSI. One or more of the source IDs can be used from the transmitting WTRU. Furthermore, a first source ID may indicate no sidelink CSI triggering (e.g., no measurement RS), while a second source ID may indicate sidelink CSI triggering (e.g., the presence of a measurement RS). Additionally, the source ID can be used interchangeably with the destination ID and can still be consistent with the examples and implementations provided herein. In examples that include slot numbers or indices, if the receiving WTRU receives the SCI in a specific slot, the receiving WTRU can measure and report the sidelink CSI.

[0110] In one example, the transmit WTRU may be triggered to transmit CSI-RS (and / or CSI reports) in the PSSCH transport when one or more of the following thirteen conditions are met.

[0111] First, resource selection can be triggered by a higher level.

[0112] Second, CBR can be higher or lower than the threshold.

[0113] Third, a HARQ NACK may have been received. A HARQ NACK can be received N times consecutively from the same WTRU, where N can be configured, predefined, or indicated.

[0114] Fourth, the 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 (such as reliability and latency), estimated channel conditions (such as channel coherence time), and / or WTRU speed.

[0115] Fifth, the QoS requirements for TB may have changed. For example, the reliability requirements for TB may have changed. The worst-case scenario for QoS requirements can change, where the worst-case scenario for QoS may be requiring one or more of the following: minimum latency, maximum reliability, maximum range, maximum data rate, and maximum packet size.

[0116] Sixth, the transmission parameters and / or scheme can be changed. For example, the rank can be changed.

[0117] Seventh, the size of TB may have changed.

[0118] Eighth, the received RSRP and the estimated PL may have changed.

[0119] Ninth, the transmit-receive distance of the WTRU may have changed. For example, when the transmit-receive distance may exceed a threshold, the transmitting WTRU may request a CSI report.

[0120] Tenth, new unicast (or multicast) links can be established.

[0121] Eleventh, the region ID for transmitting and / or receiving WTRUs can be changed.

[0122] Twelfth, it can receive DTX transmitted via sidelink. For example, after a sidelink transmission, the transmitting WTRU can receive DTX in the associated HARQ resource, and the transmitting WTRU can be triggered to transmit CSI-RS and its associated CSI reports.

[0123] Thirteenth, a CSI-RS request indication can be received from the 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 triggering 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.

[0124] In another implementation, the WTRU may not be allowed to trigger a sidelink CSI report if one or more of the following ten conditions are met.

[0125] First, the CBR can be higher (or lower) than a threshold, which can be determined based on one or more of the following parameters: QoS (or worst-case QoS), transmit-receive distance, within the MCR (e.g., transmit-receive distance within the minimum required communication range) or outside the MCR (e.g., transmit-receive distance outside the minimum required communication range), or within or outside the coverage area.

[0126] Second, it can receive HARQ-ACKs for the latest sidelink transmission. Alternatively, it can receive N consecutive HARQ-ACKs for previous sidelink transmissions.

[0127] Third, the received power of HARQ-ACK can exceed the threshold.

[0128] Fourth, the measured RSRP from the reference signal transmitted from the received WTRU may exceed the threshold.

[0129] Fifth, the transmit beam can be the same as the latest sidelink transmission (received by HARQ-ACK). The transmit beam can be referred to as an indicator for the reference signal index used for the Quasi-Same Location Type D indication or Transmit Channel Indication (TCI) status.

[0130] Sixth, QoS is below the threshold. For example, this condition may include one or more of the following: (1) minimum communication range is below the threshold; (2) reliability is below the threshold; (3) priority is below the threshold; (4) data rate is below the threshold; (5) packet size is less than the threshold.

[0131] Seventh, the transmitting WTRU (and / or receiving WTRU) can be outside (or within) the coverage area.

[0132] Eighth, the configuration may indicate that sidelink CSI feedback is not allowed. This configuration can be at least one of the following: 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.

[0133] Ninth, the transmitting WTRU can receive an out-of-coverage indication from the receiving WTRU. Furthermore, the CQI table may include a CQI field indicating out-of-coverage, and this CQI field may be used when: no other CQI value is available for the current channel conditions; the receiving WTRU is outside the MCR; and / or the current channel conditions do not meet the QoS of the packet.

[0134] Tenth, transmit N consecutive DTXs via the WTRU receiver-side link, where N can be a non-negative integer.

[0135] The following describes sidelink CSI reporting that depends on one or more measurement RSs. CSI reports can be transmitted in MAC CE or in physical layer signaling (e.g., UCI on the PUSCH, similar to that in an NR Uu link). Both MAC CE-based and physical layer signaling-based CSI reporting may be supported. 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 measurements, MAC CE-based reporting may be used, while when a second type of CSI-RS is used for CSI measurements, physical layer signaling-based CSI reporting may be used. The second condition relates to (pre)configuration. CSI reporting may be part of the configuration during link establishment or part of the resource pool configuration. In the example, configuration may be performed via pre-configuration.

[0136] The examples provided in this document may include dynamic sidelink CSI-RS indication. For example, a transmitting WTRU may indicate the presence of CSI-RS transmissions in an SCI. The WTRU may be configured with a set of CSI-RS modes for a resource pool, and the SCI indication may be an index of the configured set. In one example, the WTRU may be pre-configured with a set of CSI-RS modes. CSI-RS modes may be defined, for example, on a sub-channel basis, and the transmitting WTRU may indicate one or more of the following in the SCI: CSI-RS in each sub-channel used by the PSSCH, CSI-RS in a sub-channel used by the PSCCH, or CSI-RS in a subset of the sub-channels used by the PSSCH.

[0137] In one example, the transmit WTRU may indicate QoS requirements associated with CSI-RS transmissions (and / or CSI reports) in the SCI, wherein the QoS requirements may include one or more of the following requirements.

[0138] First, CSI reports can be applied to QoS requirements for PSSCH transmissions. QoS latency requirements determine the timing of triggered CSI feedback reports.

[0139] Second, CSI-RS can be transmitted within PSCCH, and its associated PSCCH (e.g., in SCI) can indicate the presence of CSI-RS and / or the triggering of CSI reports, and the SCI can indicate the QoS of its associated PSSCH. The QoS of CSI-RS (and / or CSI reports) can be determined based on the QoS of the PSSCH transmitted together in the time slot.

[0140] Third, the QoS associated with CSI-RS (and / or CSI reports) and the QoS associated with PSSCH can be indicated separately. For example, one or more QoS indications may be in the SCI, and the first QoS indication may be associated with PSSCH while the second QoS indication may be associated with CSI reports. Furthermore, the number of bits for the first QoS and the second QoS may differ. 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).

[0141] Furthermore, the QoS associated with CSI-RS (and / or CSI reports) can be a subset of the QoS parameters associated with PSSCH. For example, the receiving WTRU may use only a subset of the QoS parameters associated with PSSCH.

[0142] In another example, the transmitting WTRU can be configured with CSI-RS density and / or resource configuration based on QoS requirements, and the receiving WTRU can accordingly determine the QoS requirements associated with the CSI-RS transmission. In one example, the WTRU can be pre-configured with CSI-RS density and / or resource configuration. Additionally, the CSI-RS QoS requirements can be configured to be the same as those accompanying the PSSCH transmission. In one example, the CSI-RS QoS requirements can be pre-configured.

[0143] In the implementation, the WTRU can perform resource selection, resource reselection, or both for CSI report transmissions. Alternatively or otherwise, the WTRU can perform resource selection, resource reselection, or both for CSI-RS transmissions. The transmitting WTRU can transmit CSI-RS to the receiving WTRU and trigger measurements for the CSI-RS transmission. Once the receiving WTRU has performed the relevant measurements for the CSI-RS transmission, it will transmit a CSI report to the transmitting WTRU. The WTRU's MAC layer can receive CSI reports from its PHY layer. The transmitting WTRU can perform resource selection, resource reselection, or both based on the timing of receiving CSI feedback / CSI reports from lower layers.

[0144] In one implementation, if the WTRU has no pending SL authorizations for transmitting CSI-RS MAC CEs for sidelink transmission, the WTRU may trigger resource selection to reserve sidelink resources. In another implementation, if the WTRU has one or more pending SL authorizations, but these authorizations do not meet specific criteria associated with CSI-RS reporting, such as in the following examples, the WTRU may trigger resource selection, resource reselection, or both.

[0145] In one implementation, the WTRU may trigger an SL-Buffer Status Report (BSR) if it does not have any pending authorizations for transmitting CSI-RS MAC CEs for sidelink transmissions. In another implementation, the WTRU may trigger an SL-BSR if the UE has one or more pending SL authorizations, but these authorizations do not meet the specific criteria associated with CSI-RS reporting, such as in the following examples.

[0146] In one example, one or more pending authorizations may not occur within the time window or required delay associated with the CSI-RS report. Such windows may be determined based on the mechanisms defined in this disclosure.

[0147] In another example, based on some limitations such as those in the following examples, one or more pending grants may not be used for the transmission of CSI-RS reports. In one example, a logical channel associated with a MAC CE transmission cannot be transmitted to a grant due to limitations associated with the logical channel. In another example, based on the method for priority determination described in this disclosure, the determined priority of the MAC CE may prevent the MAC CE from being transmitted to a grant due to limitations associated with the logical channel. In yet another example, a grant may be associated with a destination identifier (ID) that does not match the destination to which the CSI-RS report should be sent.

[0148] In addition, the WTRU that performs resource selection, resource reselection, or both associated with a pending MAC CE can provide QoS information to the physical (PHY) layer for performing resource selection. In one example, the QoS information may include priority information.

[0149] In one example, the WTRU can determine priority information by first deriving the L2 priority associated with the MAC CE. The MAC CE can then be treated as 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 can, for example, derive L1 priorities from the derived L2 priorities based on pre-configuration, and such L1 priorities can be provided to lower layers. The PHY layer can select a resource selection window, such as the value of T2, in which resource selection is performed based on the provided L1 priorities. The L2 priorities associated with the MAC CE can be derived using any of the methods described in this disclosure for determining the Logical Channel Prioritization (LCP) procedure.

[0150] In another example, the WTRU may first derive the L2 priority associated with the MAC CE based on the CSI feedback reporting window (which may be determined as described in this disclosure) associated with the CSI feedback. Specifically, the WTRU may first determine the CSI feedback window using the methods described in this disclosure. The WTRU may then determine which of one or more logical channels configured by the WTRU is configured with a QoS flow having similar latency requirements. In one example, the latency requirement may be expressed using the PC5 5G QoS feature (5QI) (PQI). Specifically, the WTRU may select a logical channel (LCH) for which the mapped QoS flow has a latency requirement less than or equal to the latency required for CSI feedback, a latency window, or both. Alternatively, the WTRU may select an LCH for which the mapped QoS flow has a latency closest to the latency required for CSI feedback, a latency window, or both.

[0151] In another example, the WTRU may first derive the L2 priority associated with the MAC CE based on a CSI feedback reporting window (as determined in the example described in this disclosure) associated with the CSI feedback. In such an example, the WTRU may first determine the CSI feedback window using the methods described in this disclosure. The WTRU may then determine the L2 priority associated with such window. Specifically, the WTRU may select an L2 priority whose corresponding delay is less than or equal to the CSI feedback window delay. The WTRU may then provide such priority to lower layers for resource selection, resource reselection, or both. The WTRU may apply such priority in a resource selection process performed at a lower layer, a resource reselection process performed at a lower layer, or both.

[0152] In another example, the WTRU may provide its PHY layer with a CSI feedback reporting window delay or delay limit. The CSI feedback reporting window delay or delay limit may be in the form of the remaining packet delay budget (PDB) of the data to be transmitted that triggered resource selection. The WTRU may apply the CSI feedback reporting window delay or delay limit. The CSI feedback reporting window delay or delay limit may be in the form of the remaining PDB of the TB, which will be transmitted during a resource selection process performed at the PHY layer, a resource reselection process performed at the PHY layer, or both, and triggered by the TB. Specifically, the WTRU may determine the remaining PDB to be used in resource selection based on the CSI delay limit or CSI feedback window. The WTRU may determine the remaining PDB as the remaining delay up to the CSI delay limit or CSI feedback window. The remaining PDB provided to the PHY layer may represent the configured CSI feedback reporting window delay or delay limit. Alternatively or otherwise, 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 limit. The PHY layer can provide the MAC layer with a set of resources that satisfy the remaining PDB, allowing the MAC layer to select from these resources for the transmission of the CSI feedback MAC CE. In one example, the MAC layer can make a random selection.

[0153] In another example, the WTRU can instruct the PHY layer to associate resource reselection with the transmission of the CSI feedback MAC CE. The MAC layer can also provide a window to the PHY layer, or the MAC layer can indicate to the PHY layer the specific destination address or identifier of the MAC CE that triggered the reselection, allowing the PHY layer to select resources based on the window.

[0154] In some implementations, the WTRU can determine the L2 source, L2 destination, or both of the CSI-reported MAC CE. The WTRU can receive CSI-RS reports from its PHY layer and can have multiple ongoing unicast links. During MAC layer multiplexing, the WTRU can determine the L2 destination ID to which a particular MAC CE will be transmitted. For this, the WTRU needs to be able to associate the CSI-RS reports received from lower layers with the specific unicast link to which the report is targeted.

[0155] In one example, the WTRU may receive CSI-RS reports and decoded MAC PDUs from a lower layer. The WTRU may, for example, use the L2 source / destination ID of the CSI-RS report to determine the unicast link to which the CSI-RS report will be transmitted by determining the L2 destination / source ID in the decoded MAC PDU sent along 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.

[0156] In another example, if the WTRU or its MAC layer cannot decode the MAC PDU, the WTRU may discard the CSI-RS report. The WTRU may be unable to decode the MAC PDU because, for example, it cannot determine the L2 source / destination ID, or it cannot find a unicast link with the associated L2 source / destination ID indicated in the MAC PDU.

[0157] In the example, the LCP procedure may consider the CSI-RS feedback MAC CE. The WTRU may consider the presence of a MAC CE during the sidelink LCP procedure. In one example, the WTRU may prioritize destination address selection based on the destination address having one or more pending MAC CEs for the transport.

[0158] In another example, the WTRU may assign a delay value or a delay limit value to the SL CSI MAC CE. Such a value can be determined through the procedures described in any of the relevant examples in this disclosure.

[0159] In another example, the WTRU can assign L2 priority to the SL CSI-RS feedback MAC CE. The WTRU performs SL LCP by selecting the destination address of the MAC CE with the highest priority to transmit. The L2 priority of the MAC CE carrying the SL CSI report can be determined based on one or more of the following priorities: pre-configured priority, the priority of the received data, or the priority of the LCH associated with the transmission to the peer WTRU. Therefore, the WTRU can assign priority to CSI feedback transmissions. In one example, CSI feedback transmissions can be used for resource selection. Some of the priorities mentioned above will be described further below.

[0160] In one implementation, the L2 priority of the MAC CE carrying the SL CSI report can be determined based on pre-configured priorities. 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.

[0161] In one implementation, the L2 priority of the MAC CE carrying the SL CSI report can 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 derived from the priority of the peer WTRU transmission that measured the SL-CSI. For example, the WTRU may derive the L2 priority of the MAC CE from the L1 priority received in a transmission carrying the measured CSI-RS. The L2-to-L1 priority mapping may be configured at the WTRU or pre-configured at the WTRU. In another example, the WTRU may derive the L2 priority from the LCH.

[0162] In one implementation, the L2 priority of the MAC CE carrying the SL CSI report can be determined based on the priority of the LCH associated with the transmission to the peer WTRU. In one example, the WTRU can determine the L2 priority of the SL MAC CE for a transmission to a destination WTRU that needs to transmit the CSI-RS MAC CE based on the LCH configured at the WTRU. For example, the WTRU can 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.

[0163] This article provides examples involving the dropping of CSI-RS transmissions. WTRU may drop CSI-RS transmissions based on one or both of the following conditions.

[0164] First, if the CBR is higher than a threshold, the WTRU may discard CSI-RS transmissions. For example, the WTRU may be configured with a CBR threshold for the SL resource pool on which CSI-RS reports should be transmitted. If the CBR is higher than the CBR threshold, the WTRU may discard the transmission of CSI-RS reports.

[0165] Second, if the timer expires, the WTRU can discard the CSI-RS transmission. In other words, the WTRU can discard CSI-RS transmissions based on the expiration of a timer. For example, the WTRU can start a timer when it receives a CSI-RS report from the PHY layer. When the timer expires, the MAC layer can discard pending and untransmitted CSI-RS reports (MAC CE). The timer value can be set based on a mechanism similar to the mechanism described in this disclosure for setting the report window.

[0166] The following is for reference. Figure 2 Method 200 is described according to an embodiment of this disclosure. Figure 2 This is a flowchart illustrating method 200. Method 200 can be used by a WTRU (e.g., a receiving WTRU) capable of communicating with a network or another WTRU (e.g., a transmitting WTRU) via an SL. The WTRU is configured with an SR configuration set. In this disclosure, unless otherwise stated, the WTRU performing method 200 may be referred to as a receiving WTRU. The WTRU transmitting signals (e.g., CSI-RS, data, etc.) to the receiving WTRU may be referred to as a transmitting WTRU, a network, or a base station. In this disclosure, unless otherwise stated, the terms "transmitting WTRU," "base station," and "network" are used interchangeably. The WTRU receiving CSI-RS, SL authorization, and other signals from the network may be referred to as a receiving WTRU.

[0167] Method 200 may include: at 201, receiving (1) a CSI report request requesting a CSI report and (2) CSI report delay information via SL; at 202, starting a timer based on the received CSI report delay information; at 203, triggering a CSI report-specific SR transmission; and at 204, determining whether an SL authorization has been received before the timer expires. If an SL authorization has been received before the timer expires, method 200 may further include: at 205, transmitting the CSI report based on the SL authorization. And if no SL authorization has been received before the timer expires, method 200 may further include: at 206, discarding the CSI report. The different processes from 201 to 206 described above will be further described below with reference to a detailed implementation.

[0168] Therefore, the WTRU is able to communicate with the network via a side link (SL), and the WTRU is configured with a scheduling request (SR) configuration set. Furthermore, 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 via the SL. The processor is configured to: start a timer based on the received CSI report delay information; trigger a CSI report-specific SR transmission; and determine whether an SL authorization has been received before the timer expires. If an SL authorization has been received before the timer expires, the processor is further configured to transmit the CSI report via the transceiver based on the SL authorization. And if no SL authorization has 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, circuitry, batteries, etc. It is assumed that these additional components are well-known, and therefore detailed descriptions of these additional components will be omitted from this disclosure. The WTRU and its transceiver and processor will be further described below with reference to detailed embodiments.

[0169] At 201, method 200 may include: receiving (1) a CSI report request requesting a CSI report and (2) CSI report delay information via SL. The processing at 201 may be performed by the receiving WTRU.

[0170] The transmitting WTRU may transmit CSI-RS to the receiving WTRU and request reports / feedback of measurements transmitted from the transmitting WTRU using the CSI-RS. In one example, the transmitting WTRU may transmit a CSI report request along with the CSI-RS. In another example, the CSI report request may be an indication for 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 limiting of the CSI report requests disclosed in this disclosure. Other types of CSI report requests may be available, provided they help to implement the principles of this disclosure.

[0171] In one example, CSI report delay information can be provided from the network or the transmitting WTRU (e.g., via PC5 RRC signaling). In another example, CSI report delay information can be pre-configured in the receiving WTRU. In yet another example, CSI report delay information can also be determined based on one or more of the following parameters: one or more QoS parameters, CBR, MCR (e.g., within or outside the MCR), coverage (e.g., within or outside coverage), mode (mode 1 or mode 2), broadcast type (e.g., multicast or unicast), maximum rank, or mobility speed (or relative speed between two WTRUs). In one example, CSI report delay information can be received via MAC CE / RRC signaling. It should be noted that the above examples are not intended to be exclusive or restrictive of CSI report delay information. CSI report delay information can be generated / determined by any other available method, as long as it helps to achieve the principles of this disclosure.

[0172] In one example, CSI reporting delay information may be a set of information including CSI reporting delay or CSI reporting delay limits. The delay / delay limits are the same as or similar to those discussed above in this disclosure. The delay / delay limits will be further described below with reference to detailed examples. It should be noted that delay / delay limits / delay information involve delay values. Therefore, in this disclosure, unless otherwise stated, the terms "delay," "delay value," "delay limit," "delay limit value," "window," "delay window," and "delay information" are used interchangeably.

[0173] Then, method 200 may proceed to 202. At 202, method 200 may include: starting a timer based on the received CSI report delay information. In one example, receiving the 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 a delay / delay limit in the CSI report delay information. The timer may be implemented by a processor using software, algorithms, etc. It should be noted that the above examples are not intended to be exclusive or limiting of the timers disclosed in this disclosure.

[0174] Then, method 200 may proceed to 203. At 203, method 200 may include: triggering a CSI reporting-specific SR transmission. The SR transmission may be a transmission from the receiving WTRU to the transmitting WTRU (which sends a CSI-RS to the receiving WTRU). The CSI reporting-specific SR transmission may indicate to the receiving WTRU that it wants to perform a CSI report, and thus trigger the transmitting WTRU or the network to determine / allocate sidelink resources for the CSI report.

[0175] 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, timeslot, frequency, etc. It should be noted that the above parameters regarding the SR configuration are not intended to be exclusive or restrictive of the SR configuration. After selecting / determining the SR configuration, the receiving WTRU may transmit the SR to the transmitting WTRU (which sends CSI-RS to the receiving WTRU) or the network based on the SR configuration.

[0176] In one example, each of the SR configuration sets is associated with pre-configured CSI report delay information from a pre-configured CSI report delay information set. The pre-configured CSI report delay information set may include multiple pre-configured CSI report delay information sets. Generally, the pre-configured CSI report delay information may resemble the CSI report delay information described above in CSI reporting. For example, the pre-configured 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., within or outside MCR), coverage (e.g., within or outside coverage), mode (mode 1 or mode 2), broadcast type (e.g., multicast or unicast), maximum rank, or mobility speed (or relative speed between two WTRUs). The pre-configured CSI report delay information may be pre-configured by the receiving WTRU, the transmitting WTRU, or the network. For example, the pre-configured CSI report delay information may be pre-configured or predetermined by the transmitting WTRU, which can then transmit the pre-configured CSI report delay information to the receiving WTRU.

[0177] Pre-configured CSI reporting delay information may include CSI reporting delays (e.g., 10ms, 20ms, etc.) or CSI reporting delay limits. In one example, a pre-configured CSI reporting delay information may include only one CSI reporting delay (or delay limit). In the set of pre-configured CSI reporting delay information, there are two pre-configured CSI reporting delay information, i.e., two CSI reporting delays (i.e., one is 10ms and the other is 20ms). Simultaneously, 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 10ms CSI reporting delay, while the second SR configuration may be associated with a 20ms CSI reporting delay. It should be noted that the above examples regarding SR configurations and pre-configured CSI reporting delay information sets are not intended to be exclusive or limiting of this disclosure.

[0178] In one example, the WTRU may be configured with a mapping from a set of SR configurations to a pre-configured CSI reporting delay information set. This mapping indicates the relationship between the SR configurations and the pre-configured CSI reporting delays within the pre-configured CSI reporting delay information. In one example, multiple SR configurations may be mapped to a single pre-configured CSI reporting delay. In this case, the receiving WTRU may select an SR configuration from among the multiple SR configurations used for CSI reporting based on the priority of the SR configurations. In one implementation, this mapping may be pre-configured by the receiving WTRU. In another example, the mapping may be provided from the base station. It should be noted that the above description of the mappings is given by way of example only and is not intended to be exclusive or limiting of this disclosure.

[0179] In one implementation, method 200 may further include providing the calculated latency of the CSI report to the network or the transmitting WTRU. In one example, the calculated latency may be the current latency for CSI reporting that the receiving WTRU possesses. In another example, the calculated latency may be the desired latency for CSI reporting that the receiving WTRU might wish to possess. The calculated latency may be the same as or similar to the CSI reporting latency described above. For example, the calculated latency may be 10 ms, 20 ms, etc. The calculated latency may be determined / calculated in a manner similar to that used to determine the pre-configured CSI reporting latency. It should be noted that the above examples of calculated latency are not intended to be exclusive or limiting of this disclosure.

[0180] Then, method 200 may proceed to 204. At 204, method 200 may include: determining whether an SL grant has been received before the timer expires. For example, once the base station receives an SR transmission, it may determine and allocate resources to the receiving WTRU, and then transmit to the receiving WTRU an SL grant instructing the receiving WTRU to 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 an 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 execute different procedures based on the result of the procedure at 204. The following description will further describe the procedures following the procedure at 204.

[0181] If at 204 the processor determines that an SL grant has been received before the timer expires, method 200 may proceed to 205. At 205, method 200 may further include: transmitting the CSI report based on the SL grant. In one example, the SL resource indicated in the SL grant may be used to transmit the CSI report. The SL grant may indicate parameters for CSI report transmission. Therefore, the processor may control the transmission of the CSI report through the transceiver based on the SL grant.

[0182] If at 204 the processor determines that no SL authorization has been received before the timer expires, method 200 may proceed to 206. At 206, method 200 may further include: discarding the CSI report. In this case, the receiving WTRU will not transmit the CSI report.

[0183] This document provides examples of instructions relating to reporting SL-CSI to the network. A WTRU can indicate the presence of a pending SL-CSI report MAC CE to be transmitted on the sidelink in order to receive a sidelink grant from the network. In one example, the WTRU can receive a sidelink grant in Mode 1. In one implementation, the WTRU can trigger a report to the network when the MAC layer receives a CSI report to be transmitted to the peer WTRU. Specifically, the WTRU can trigger a scheduling request (SR) without any SL grants. Furthermore, the WTRU can trigger an SR if the MAC layer receives a trigger to transmit a CSI report and none of the existing SL grants meet the delay requirements for the CSI report to be transmitted. The WTRU can be configured with a dedicated SR resource for indicating the presence of an SL MAC CE to be transmitted. Alternatively or additionally, when the WTRU has a pending SL MAC CE to be transmitted, it can select from one of the configured SL-SR resources. Specifically, WTRU can select the SL-SR to trigger when an SL-CSI report is present based on one or more of the following parameters: pre-defined mapping, network configuration, LCH, or the priority of the received transmission that triggered the SR transmission. Some of the above parameters will be described in detail below.

[0184] In one example, the WTRU can select the SL-SR to trigger when an SL-CSI report is available, based on an explicit mapping from the SL MAC CE pre-defined at the WTRU to one of the configured SL-SR resources.

[0185] In another example, the WTRU can select the SL-SR to trigger when an SL-CSI report is present, based on network configuration. In one example, the configuration can be pre-configured. For example, the WTRU can be configured with an LCH-to-SR mapping, where the LCH associated with the SLMAC CE is part of such a mapping. In one example, the WTRU can be configured with a mapping of CSI report latency to SR configurations. The WTRU can select the SR configured for CSI reports with a given latency requirement. For example, a range of latency values ​​corresponding to each SR configuration can be provided to the WTRU, and when the latency falls within the latency range associated with that SR, the WTRU can select the associated SR configuration. For example, the WTRU can be configured with a finite number of latency values ​​for CSI reports and can select the SR configuration associated with each configuration. The latency of the CSI report can be determined by the WTRU based on any process described in the examples of this disclosure. Therefore, the WTRU can select the SR configuration for SR transmission based on the latency limits of the CSI report that triggered the SR.

[0186] Latency can be further provided by the peer WTRU. In one example, latency can be provided via PC5 RRC signaling. The current latency can be maintained at the WTRU and change with events or periodically. For example, the current latency can be maintained at the WTRU and changed each time the WTRU receives a new value of latency to use from the peer WTRU or the network. For example, the WTRU can periodically calculate its latency value and maintain that calculated latency value throughout the cycle. In one example, the entire cycle can continue until the next calculation. For example, when any factor affecting that value (e.g., speed) changes by a certain amount, the WTRU can calculate a new latency value. Latency can be provided to the MAC layer by the PHY layer for SR triggering.

[0187] In another example, the WTRU can select the SL-SR to trigger when an SL-CSI report is present, based on the LCH or priority of the received transmission that triggered the SR transmission. For example, the WTRU can determine the priority or LCH of the received transmission that triggered the SL-CSI report and can select an SR of equivalent priority. In one example, the LCH could be an LCH whose L2 priority is the same as the priority in the received transmission for which SL_CSI was measured.

[0188] The WTRU can trigger a BSR and report the existence of a CSI report (e.g., a CSI report SLMAC CE) to be sent to the peer WTRU. For example, the WTRU can report the intention to transmit an SL MAC CE as part of the buffer state of a specific logical channel or logical channel group in the BSR. The SL MAC CE can be configured, pre-configured, or predefined to a logical channel or logical channel group in the side link.

[0189] In one example, the WTRU can report the intent to transmit an SL MAC CE by transmitting an explicit indication in the BSR. In another example, the WTRU can report the intent to transmit an SL MAC CE by using a different BSR format.

[0190] The computational delay can be transmitted via SR transmissions or control messages. In one example, the computational delay can be transmitted as part of an SR transmission. Therefore, when the WTRU receives an SR transmission, it will obtain the computational delay and use it to schedule sidelink resources for transmitting CSI reports.

[0191] For example, the WTRU may provide the network with a calculated CSI delay limit or window determined based on the method described in this disclosure. Calculating the CSI delay limit or window helps the network schedule sidelink resources used for transmitting CSI reports. The WTRU may provide the calculated CSI delay limit or window for CSI reporting to the network implicitly, explicitly, or in both ways.

[0192] In one example, the WTRU can provide a calculation of the CSI delay limit or window when a CSI report is triggered. Specifically, the WTRU can instruct the calculation of the CSI delay limit or window each time a CSI report is triggered.

[0193] In one example, when the WTRU requests new resources from the network, it can provide a calculated CSI delay limit or window. Specifically, when the WTRU determines which sidelink resources to request for transmitting CSI reports, it can indicate a window or delay (or delay limit). For example, the value of the window or delay limit can be associated with the request for the resources used to transmit the CSI request.

[0194] In another example, the WTRU can periodically provide calculation CSI delay limits or windows. For instance, the WTRU can be configured with periodic reports of CSI windows, and these reports can be applied to the current calculation window for each periodically triggered period.

[0195] In another example, WTRU can provide calculation CSI delay limits or windows when the current / applicable CSI window changes. For instance, when a value changes from a previously reported value (potentially by a specific amount), WTRU can report the currently applicable calculation window.

[0196] WTRUs can explicitly report windows in control messages such as RRC messages or MAC CE messages. For example, WTRUs can report CSI delay limits or windows in side-link UE information messages during unicast link initiation and / or reconfiguration between WTRUs. For example, WTRUs can report CSI delay limits or windows provided by peer WTRUs in PC5-RRC signaling during unicast link establishment.

[0197] The WTRU can implicitly report windows to the network by selecting the UL resource configured for each possible value. For example, the WTRU can be configured with different PUCCH resources or SR configurations, each associated with a different delay. The WTRU selects the PUCCH resource or SR configuration corresponding to the delay of the triggered CSI report associated with the current delay.

[0198] In another example, the WTRU can be configured with congestion-based transmission parameters specific to CSI report transmissions. In one example, the WTRU can be configured with a specific set of congestion-based transmission parameters to be used for transmitting CSI reports. In another example, the congestion-based transmission parameters can be used for congestion control. Specifically, for transmissions that include CSI reports, the WTRU can determine a specific set of congestion-based transmission parameters configured specifically for such transmissions. Alternatively, the WTRU can associate the congestion-based parameters to be used for CSI report transmissions with a configuration for one of the logical channels.

[0199] For example, the WTRU can associate congestion-based parameters with a configuration 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.

[0200] In another example, the WTRU can associate a congestion-based parameter with a configuration used for the logical channel associated with a CSI report request. In one example, the WTRU can use a congestion-based parameter associated with the priority in a received SCI that also requests a CSI report.

[0201] This document provides examples related to determining wideband CSI. In one example, a PSSCH transmission bandwidth is available for wideband CSI. In another example, the transmit WTRU may determine whether resources reserved for PSSCH transmission can provide wideband CSI based on the bandwidth of the PSSCH transmission. For example, the transmit WTRU may determine PSSCH transmission resources to provide wideband CSI if: the number of subchannels used for PSSCH transmission is higher than a threshold; and / or the number of subcarriers used for PSSCH transmission is higher than 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.

[0202] In addition, the transmitting WTRU can indicate a CSI request in the SCI associated with the CSI-RS transmission. The receiving WTRU can send a CSI report corresponding to the CSI transmission. When a CSI-RS transmission is triggered, the transmitting WTRU can determine the accompanying PSSCH transmission parameters based on previous CSI reports, (pre)configured CSI reports, and / or minimum CSI reports.

[0203] In another example, the transmitting WTRU can adjust the received CSI and apply the adjusted CSI to the scheduled PSSCH transmission. For example, the adjustment can be based on 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 the PSSCH transmission, (2) the estimated channel frequency selectivity, or (3) QoS requirements such as reliability, delay, priority, and minimum communication range (MCR).

[0204] For example, if the frequency difference between a subchannel reserved for PSSCH transmission and a subchannel 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 transmit WTRU may apply an offset (e.g., 1 or 2 units) to reduce the received CQI before applying it to PSSCH transmission. Furthermore, if the QoS requirements (e.g., the reliability of PSSCH transmission (e.g., 1E-5)) are higher than those associated with CSI-RS transmission (e.g., 1E-3), the transmit WTRU may apply an offset (e.g., 4 or 5 units) to reduce the received CQI before applying it to PSSCH transmission.

[0205] This document describes resource reselection triggering based on CSI-RS requirements. In one example, a transmit WTRU can trigger resource reselection when a CSI-RS transmission is triggerable and the PSSCH transmission bandwidth is below a threshold (e.g., 2 sub-channels).

[0206] The examples provided in this document include multiple CSI-RS transmissions with distributed frequency resources. In one example, the transmitting WTRU can request a CSI report via a set of CSI-RS transmissions. The transmitting WTRU can select different frequency resource allocations (e.g., sub-channels) for each PSSCH transmission that includes CSI-RS transmissions. The purpose can be to span multiple CSI-RS transmissions across the entire bandwidth. For example, in mode 1, the base station can schedule mode-based PSSCH transmissions. In mode 2, the WTRU can select non-overlapping frequency resources that extend across the system bandwidth for multiple PSSCH / CSI-RS transmissions. The transmitting WTRU can indicate the CSI request in the SCI associated with the last CSI-RS transmission among the multiple CSI-RS transmissions. The receiving WTRU can send a CSI report corresponding to that set of CSI-RS transmissions. The CSI report can be based on measurements within the bandwidth of each CSI-RS transmission. For example, the receiving WTRU can report the average CSI, maximum CSI, and / or minimum CSI for all measurements.

[0207] The examples provided in this document include CSI-based sidelink resource selection. In one example, a sidelink mode is disclosed, in which a WTRU (or transmitting WTRU) can select sidelink resources from a resource pool for sidelink transmission. This sidelink may be referred to as Mode 2. Mode 2 is interchangeable with the sidelink mode selected by the WTRU, the WTRU autonomous resource selection mode, the mode selected by the WTRU, the resource mode determined by the WTRU, and the awareness-based resource selection mode.

[0208] The examples provided in this document include sub-channel prioritization. In one example, one or more resource selection schemes (or modes) can be used based on the availability of CSI at the WTRU. For example, if the CSI of one or more sub-channels in the resource pool is available, a first resource selection scheme can be used. If the CSI of one or more sub-channels in the resource pool is unavailable, a second resource selection scheme can be used.

[0209] When the WTRU is in Mode 2, it can be configured or instructed to execute one of the resource selection schemes. Additionally, when the WTRU activates, triggers, or uses CSI feedback for sidelink transmissions (e.g., for unicast traffic), it can execute a first resource selection scheme. Furthermore, when the WTRU does not have CSI information for one or more sub-channels in the resource pool for Mode 2 transmissions, it can execute a second resource selection scheme.

[0210] 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 the sidelink scheme; (2) if CSI information is available for all sub-channels; (3) if CSI information is available for at least N sub-channels, where N may be configured, indicated, or determined based on the total number of sub-channels; (4) if QoS is above a threshold; (5) if WTRU is within MCR (e.g., within the minimum communication range); (6) if retransmission is required; (7) if CBR is below (or above) a threshold.

[0211] In another example, one or more sub-channels may be available in a resource pool, and the WTRU may determine which sub-channel is used for sidelink transmission based on one or more of the following parameters: availability of CSI information, validity of CSI information, RSRP of the sub-channel, reception of CSI, sub-channel reserved by another WTRU, sub-channel with PSFCH resources, or CQI / RI value of the sub-channel. Some of the above parameters will be described in detail below.

[0212] This section describes parameters regarding the availability of CSI information. Examples involving CSI information may include CQI, PMI, and / or RI. Furthermore, one or more subchannels in a resource pool may or may not have CSI information. For example, transmitting a WTRU may trigger CSI reporting for a subset of subchannels where PSSCH can be transmitted, and other subchannels may not have CSI when the WTRU determines one or more subchannels for sidelink transmission. Additionally, 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.

[0213] This section describes the parameters regarding the validity of CSI information. If a CSI is received after a time threshold, it may be considered outdated and the WTRU may consider (or assume) the CSI invalid. Therefore, it may be used or assumed to have the same priority as a subchannel without a CSI. Additionally, for resource selection, a subchannel with a CSI received after the time threshold may have a lower (or higher) priority than a subchannel with a CSI received before the time threshold. Furthermore, the time gap between CSI reception and resource selection may be referred to as the CSI validity gap (CVG), and a CSI received for a subchannel with a longer CVG may be less accurate than a CSI received for a subchannel with a shorter CVG. If one or more subchannels have the same priority, for resource selection, a subchannel with a shorter CVG may have a higher priority than another subchannel with a longer CVG.

[0214] This section describes parameters regarding the RSRP of a subchannel. For example, the WTRU can measure the RSRP of one or more subchannels in a resource pool and select a first subset of subchannels whose RSRPs may be below a threshold (e.g., a threshold corresponding to -10 dBm). The WTRU can then determine a second subset of subchannels from the first subset based on the availability of the CSI for each subchannel and / or the CVG for each subchannel. If there are still more than one subchannel in the second subset, the WTRU can randomly determine which subchannel in the second subset will be used for sidelink transmission.

[0215] This section describes the parameters for receiving SCIs. For example, the WTRU can blindly decode the SCI in each subchannel, and if the WTRU receives an SCI in a subchannel, the WTRU can exclude that subchannel from the first set of subchannels.

[0216] This section describes the parameters for a subchannel reserved by another WTRU. A subchannel can be reserved by another WTRU, and the QoS of the reserved resource can be lower than the QoS of packets that the transmitting WTRU can send on the sidelink. This subchannel resource can be selected for sidelink transmission and is referred to as a reserved subchannel with lower QoS (RSLQ). Furthermore, a subchannel without reservation can be referred to as a non-reserved subchannel (NRS). Additionally, in Mode 2 resource selection, RSLQ can have a lower (or higher) priority than NRS. RSLQ can have a higher priority than NRS if RSLQ has CSI information and NRS does not. In another example, regardless of the valid CSI on the subchannel, RSLQ can have a lower (or higher) priority than NRS.

[0217] This section describes parameters regarding subchannels with PSFCH resources. Subchannels with PSFCH resources may have a lower priority than subchannels without PSFCH resources. For example, within a time slot, a first subset of subchannels may have PSFCH resources, while a second subset of subchannels may not, where the second subset may have a higher priority than the first subset. In one example, the WTRU may first measure the RSRP of one or more subchannels in the resource pool and determine a first subset of subchannels that may have an RSRP below a threshold. Then, the WTRU may 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 for sidelink transmission.

[0218] This section describes parameters regarding the CQI / RI values ​​of sub-channels. Sub-channel priority can be determined based on the CQI / RI value of each sub-channel. Sub-channels with higher CQI / RI values ​​can have higher priority than sub-channels with lower CQI / RI values.

[0219] It should be noted that the terms "first" and "second" used in the first subset and second subset of the subchannels described above are used only for the purpose of distinguishing these two subsets of the subchannels from each other, and therefore are not intended to limit this disclosure. For example, the first subset of the subchannels may be used as the second subset of the subchannels, and the second subset of the subchannels may be used as the first subset of the subchannels, and still be consistent with the examples and embodiments provided herein.

[0220] The description here includes examples of subchannel sensing. In one example, the WTRU may perform sensing on a subchannel with valid CSI information, while the WTRU may skip performing sensing on a subchannel without valid CSI. Valid CSI information may include one or more of the following parameters: associated CSI, CSI received less than x time slots earlier, or a CQI / RI value above a threshold. Some of the parameters mentioned above are described in detail below. The associated CSI may be, for example, CQI, PMI, and / or RI. Furthermore, 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, the CSI of the subchannel may be received after time slot #nx. Furthermore, x may be determined based on one or more of these parameters: mobility; QoS (e.g., latency requirements); or transmission broadcast type (e.g., multicast or unicast).

[0221] Examples of sidelink CSI reports are included in this document. The receiving WTRU may report a 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 the CSI-RS transmission; (2) the presence of a CSI indicated in an SCI associated with the CSI-RS transmission; (3) a CBR; or (4) an MCR. Some of the above parameters will be further described below.

[0222] For example, when the receiving WTRU receives an indication of the existence of a CSI-RS but no SCI requesting a CSI, the receiving WTRU may measure the CSI based on the indicated CSI-RS and store the measurement result but not report the CSI. In another example, the presence of CSI may be indicated in an SCI associated with a CSI-RS transmission. In yet another example, when the receiving WTRU measures an out-of-range CQI value, the receiving WTRU may send a CQI if the CBR is below a threshold. Otherwise, the receiving WTRU may not send a CQI. Additionally, for example, when the receiving WTRU is outside the MCR, the receiving WTRU may not send a CSI report.

[0223] The following will refer to Figure 3 Describe the CSI reporting time window. Figure 3 This is a timing diagram showing an example of a CSI reporting time window. (Example...) 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 begin at time slot #n+k1 and end at time slot #n+k2 when the CSI report is triggered at time slot #n. This time window may be referred to as the CSI Reporting Time Window (CSI-TW). One or more examples from the following examples may be applied.

[0224] For example, k1 and k2 can be non-negative integers, i.e., k1 ≥ 0 and k2 ≥ 0. In addition, each of k1 and k2 can be a predefined number (e.g., k1 = 4).

[0225] In another example, k1 can be determined based on the processing capacity of the WTRU. For instance, the first WTRU may have a larger processing capacity, allowing it to process faster (e.g., k1 = 2), while the second WTRU may have a smaller processing capacity, potentially making it slower to process (e.g., k1 = 4). The processing capacity (e.g., the k1 value) can be indicated via PC5-RRC during RRC connection establishment.

[0226] In another example, k2 can be determined as a function of k1. For example, k2 = k1 + Xk, where Xk can 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 will be described below. In one example, if CBR is less than a threshold, a first Xk can be used. Otherwise, a second Xk can be used. The first Xk can be less than the second Xk. In the example using MCR, in-MCR and / or out-of-MCR can be used. In the example using coverage, in-coverage or out-of-coverage can be used. In the example using mode, mode 1, mode 2, or both can be used. In the example using broadcast type, multicast, unicast, or both can be used.

[0227] In another example, k1 can be determined as a function of one or more of the following parameters: (1) the number of sub-channels, (2) the number of CSI processes, or (3) the configured CSI feedback. For example, the number of sub-channels can be the total number of sub-channels in the pool. In one example, the number of sub-channels can be the number of sub-channels already allocated for CSI-RS transmission. In another example, the number of sub-channels can be the number of sub-channels used for PSSCH transmission.

[0228] In the example that includes the number of CSI procedures, a CSI procedure can be a CSI measurement used for CSI-RS transmission. A WTRU can be requested to measure more than one CSI-RS at a time, for example, from the same WTRU or different WTRUs. Therefore, multiple CSI procedures can exist.

[0229] In examples that include configured CSI feedback, a set of CSI feedback types can be used. For example, different subsets of CSI feedback types (e.g., CQI, PMI, RI, L1-RSRP, etc.) can be configured.

[0230] In another example, k1 and / or k2 can be indicated in the associated SCI for CSI feedback triggering. Furthermore, k1 and / or k2 can be determined based on one or more of the following parameters: one or more QoS parameters, CBR, MCR (e.g., within or outside MCR), coverage (e.g., within or outside coverage), mode (mode 1 or mode 2), transport broadcast type (e.g., multicast or unicast); and / or maximum rank.

[0231] In one example, when the receiving WTRU may be unable to report the triggered CSI within a 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) the receiving WTRU may increase the k2 value if the QoS of the traffic is higher than a threshold.

[0232] The following describes CSI report triggering with a reporting time window. In one example, a transmitting WTRU may trigger a receiving WTRU to perform up to N sidelink CSI reports within a time window. The time window can be a CSI Reporting Time Window (CSI-TW). The number N can be determined based on one or more examples below.

[0233] In one example, N can be the same as the number of time slots within CSI-TW.

[0234] In one example, N=1 can be true for the same subchannel. For instance, a transmitting WTRU may trigger a single CSI report for the subchannel within a time window. A receiving WTRU may not want to receive more than one CSI report trigger for the same subchannel within a time window. Furthermore, if a receiving WTRU receives multiple CSI report triggers for the same subchannel within a time window, the receiving WTRU may ignore the trigger, or the WTRU may report only a single CSI report triggered by one or more CSI report triggers.

[0235] In one example, N can be predetermined or configured. In another example, N can be determined based on the length of the time window or the number of time slots within the time window.

[0236] In another example, a time window can be configured, determined, or used to trigger CSI reporting and / or CSI-RS transmissions. Within each time window, the WTRU can trigger a single CSI reporting and / or CSI-RS transmission.

[0237] Time windows can be used or defined according to one or more sub-channels (or a group of sub-channels). Therefore, if the transmitting WTRU triggers a receiving WTRU to report a CSI for a sub-channel, it may not be allowed for the transmitting WTRU to trigger the same receiving WTRU to report a CSI for the same sub-channel within the time window. However, the transmitting WTRU can trigger the same receiving WTRU to report another CSI for a different sub-channel. Alternatively, the transmitting WTRU can trigger different receiving WTRUs to report another CSI for the same sub-channel within the time window.

[0238] Time windows can be determined or configured according to resource pools, WTRUs, and / or operating modes (e.g., Mode 1, Mode 2). Furthermore, time windows can be determined based on one or more of the following parameters: one or more QoS parameters, CBR, MCR (e.g., within or outside MCR), coverage (e.g., within or outside coverage), mode (Mode 1 or Mode 2), transmission broadcast type (e.g., multicast or unicast), maximum rank, and / or mobility speed (which can be considered as the relative speed between two WTRUs). Additionally, time windows can be determined based on the number of time slots available for sidelink transmission.

[0239] The following describes the discarding of triggered CSI reports. In one example, the receiving WTRU may discard the triggered CSI report when one or more subsequent events occur.

[0240] In the first event, if the number of CSI reports triggered within a time window is greater than Z, the receiving WTRU may discard one or more of the received CSI report triggers, where Z may be determined based on one or more of the following parameters: WTRU capability, CBR range or resource pool CBR, coverage (within or outside coverage), or operating mode.

[0241] In the second event, the receiving WTRU may determine which CSI report to discard based on one or more of the following parameters: the latest CSI report triggered, 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 mobility speed.

[0242] In the third event, when the WTRU triggers a CSI report, the transmitting WTRU can indicate the priority level of the CSI report. This priority level can be indicated separately from the priority level of the PSSCH transmission. If a CSI report is triggered, the receiving WTRU can determine whether to discard the CSI report based on its priority level.

[0243] The CSI reporting on the PSSCH is described below. In one example, the receiving WTRU may send CSI report bits multiplexed with the PSSCH transport. The receiving WTRU may determine the resource allocation and coding rate of the CSI report bits based on the QoS requirements associated with the CSI-RS transport, the PSSCH transport 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 transport may be indicated in the SCI of the CSI-RS transport. In one example, the QoS requirements associated with the CSI-RS transport may be the same as those accompanying the PSSCH transport. In one example, the QoS requirements associated with the CSI-RS transport may be indicated in the density and / or resource allocation of the CSI-RS transport.

[0244] The receiving WTRU can indicate the presence of a CSI report in a PSSCH transmission within the SCI. In one example, the receiving WTRU can send a CSI report in the PSSCH without user data. Because the CSI report has a small payload, the receiving WTRU can use a subset of PSSCH resources, such as subchannels and / or symbols. The receiving WTRU can indicate resource allocation using subchannels in the SCI associated with the PSSCH transmission. The selection of such a subset of resources can be based on the CSI-RS and its accompanying PSSCH transmission resources (e.g., CSI-RS and / or PSSCH subchannel numbers, slot numbers, and / or WTRU L1 ID information).

[0245] The following describes the reuse of multiple CSI reports. Figure 4 This is a timing diagram illustrating an example of multiplexing multiple CSI reports. The receive WTRU can receive one or more CSI report triggers, and the receive WTRU can be required to report more than one CSI report at a time. The receive WTRU can receive multiple consecutive CSI report triggers, and the CSI report time windows can overlap, such as... Figure 4 As illustrated in the example, during the overlapping time window, the receiving WTRU can report more than one CSI report. Furthermore, the receiving WTRU can receive CSI reports from more than one transmitting WTRU, and the CSI reporting time windows can completely or partially overlap.

[0246] In one example, one or more CSI reports can be multiplexed over a PSCCH transport. For instance, one or more CSI reports can be juxtaposed as a payload with a CSI report index. If one or more CSI reports target the same WTRU (e.g., the same transmit WTRU), then one or more CSI reports can be juxtaposed.

[0247] Figure 5This is a sequence diagram illustrating an example of a reused CSI report with a CSI report index. (Example...) Figure 5 As shown, the payload may include one or more CSI information entries, and each CSI information entry may include a CSI report index. Multiplexed CSI reports may be transmitted or reported by the receiving WTRU on the PSSCH / PSCCH.

[0248] 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 slot or subframe index that triggered the CSI report, the subchannel index, the source ID, or the destination ID. In the example, a subchannel with a subchannel index may include the associated PSCCH / PSSCH. Furthermore, if more than one subchannel is used, the first or last subchannel in the subchannel set may be used.

[0249] In one example, one or more CSI reports can be multiplexed within a subchannel, where the subchannel may have one or more resource blocks (RBs) and OFDM symbols. In one example, FDM of the CSI report can be performed. In one example, one or more CSI reports can be multiplexed across different frequency resources. For example, a first CSI report can be transmitted in a first RB within the subchannel, and a second CSI report can be transmitted in a second RB within the subchannel. In another example, a first set of RBs can be used for the first CSI report, and a second set of RBs can be used for the second CSI report.

[0250] In one example, a TDM (Transmission Management System) for CSI reports can be executed. For instance, one or more CSI reports can be reused across different OFDM symbols.

[0251] In one example, both FDM and TDM CSI reports can be performed. For instance, one or more CSI reports can be reused with different RB and OFDM symbols.

[0252] The associated time / frequency resources within a subchannel used for CSI reporting (e.g., the CSI report index) can be determined based on the CSI report index, source ID and / or destination ID and / or subchannel index.

[0253] In another example, if multiple CSI reports are triggered for the same subchannel, the WTRU can report the latest CSI report trigger. Otherwise, the WTRU can reuse one or more CSI report triggers and report them if multiple CSI reports are triggered for different subchannels.

[0254] If one or more CSI reports are triggered on the same sub-channel, the WTRU can report the latest CSI trigger. If one or more CSI reports are triggered on different sub-channels, the WTRU can report the multiplexed CSI reports. If one or more CSI reports are triggered on different sub-channels, the WTRU can report the CSI reports at different times.

[0255] The examples provided in this document may include prioritization of CSI reports and other transmissions. A WTRU may need to transmit one or more sidelink transmissions in a time slot, where the WTRU may transmit a subset of the sidelink transmissions. Each sidelink transmission may be at least one of PSCCH / PSSCH, PSFCH, S-SSB, and / or PSBCH.

[0256] In one implementation, if one or more sidelink transmissions are based on PSCCH / PSSCH, the first PSSCH may have a higher priority than the second PSSCH.

[0257] In one example, the first PSSCH could be a PSSCH that includes both CSI from a higher layer and sidelink packets, while the second PSSCH could be a PSSCH that includes only CSI from a higher layer (i.e., excluding sidelink packets). A PSSCH that includes only CSI may have a lower priority than a 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 discard one or more sidelink transmissions, it can discard the PSSCH with the lower priority.

[0258] In one example, the first PSSCH could be a PSSCH that includes both CSI and sidelink packets from a higher layer, while the second PSSCH could be a PSSCH that includes only sidelink packets from a higher layer (i.e., excluding CSI). A PSSCH that includes both CSI and sidelink packets can have a higher priority than a PSSCH that includes only sidelink packets (i.e., the second PSSCH can have a lower priority than the first PSSCH). If the WTRU needs to discard one or more sidelink transmissions, it can discard the PSSCH with the lower priority.

[0259] In one example, the first PSSCH could be a PSSCH that only includes sidelink packets from higher layers (i.e., excluding CSI), and the second PSSCH could be a PSSCH that only includes CSI from higher layers (i.e., excluding sidelink packets). A PSSCH that only includes CSI can have a lower priority than a PSSCH that only includes sidelink packets (i.e., the second PSSCH can have a lower priority than the first PSSCH). If the WTRU needs to discard one or more sidelink transmissions, it can discard the PSSCH with the lower priority.

[0260] In another example, if one or more sidelink transmissions are based on a PSSCH that includes only CSIs, the priority of one or more PSSCHs can be determined based on one or both of the following methods: First, a PSSCH that includes CSIs used only for higher QoS (e.g., priority level) may have a higher priority than a PSSCH that includes CSIs used only for lower QoS (e.g., priority level). QoS can be the QoS of the PSSCH transmitted along with the CSI-RS used for CSI reporting. Alternatively, QoS can be indicated in the SCI that can trigger a CSI report. Second, CSIs with higher CQI / RI may have a higher priority.

[0261] Although features and elements have been described above in specific combinations, those skilled in the art will understand that each feature or element may be used alone or in any combination with other features and elements. Furthermore, the methods described herein may be implemented in a computer program, software, or firmware incorporated in a computer-readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted over wired or wireless connections) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, read-only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media (such as internal hard disks and removable disks), magneto-optical media, and optical media (such as CD-ROM disks and digital versatile optical discs (DVDs)). A processor associated with the 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 used in a first wireless transmit / receive unit (WTRU), the method comprising: Receive a message from the second WTRU indicating the delay limit for transmitting sidelink channel state information (SL-CSI) reports; Receive an instruction from the second WTRU to transmit the SL-CSI report to the second WTRU; and Resource selection for transmitting the SL-CSI report is performed from available resources that appear within the time period defined by the delay limit.

2. The method of claim 1, wherein the message indicating the delay limit is received via PC5-Radio Resource Control (PC5-RRC) signaling.

3. The method of claim 1, wherein the first WTRU is configured with a mapping between a scheduling request (SR) configuration and a corresponding CSI report delay value.

4. The method according to claim 1, further comprising: The computational delay of the SL-CSI report is transmitted to the second WTRU.

5. A first wireless transmit / receive unit (WTRU), comprising: Transceiver; and processor; The transceiver and the processor are configured as follows: Receive a message from the second WTRU indicating the delay limit for transmitting sidelink channel state information (SL-CSI) reports; Receive an instruction from the second WTRU to transmit the SL-CSI report to the second WTRU; and Resource selection for transmitting the SL-CSI report is performed from available resources that appear within the time period defined by the delay limit.

6. The first WTRU of claim 5, wherein the message indicating the delay limit is received via PC5-Radio Resource Control (PC5-RRC) signaling.

7. The first WTRU of claim 5, wherein the first WTRU is configured with a mapping between a scheduling request (SR) configuration and a corresponding CSI report delay value.

8. The first WTRU of claim 5, wherein the transceiver is further configured to transmit the computational delay of the SL-CSI report to the second WTRU.

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