Method and apparatus for joint CSI measurement in NCJT

Abstract

A method and apparatus for joint channel state information (CSI) measurement are described herein. The method may include receiving a channel state information reference signal (CSI-RS) from a first and a second transmit / receive point (TRP), determining a CSI, selecting one of the TRPs as a primary TRP and selecting the remaining one of the first TRP or the second TRP as a secondary TRP. The method may include reporting information indicative of the first CSI for the primary TRP and receiving a second CSI-RS from the TRP. The method may include determining a second CSI and a precoding matrix indicator (PMI) for the primary TRP and determining channel coding information for the primary TRP. The method may include determining a second CSI for the secondary TRP, determining based on the channel coding information, the second CSI for the secondary TRP, and the PMI for the secondary TRP, and reporting information indicative of the PMI for the second TRP.

Description

[Technical Field]

[0001] (Cross-reference of related applications) This application claims the interests of U.S. Provisional Patent Application No. 63 / 136,513, filed on 12 January 2021, and U.S. Provisional Patent Application No. 63 / 249,392, filed on 28 September 2021, the contents of which are incorporated herein by reference. [Background technology]

[0002] The Third Generation Partnership Project (3GPP) specification for Multiple Input-Multiple Output (MIMO) in New Radio (NR) includes extensions for CSI reporting for DL ​​multi-transmit / receive point (TRP) and / or multi-panel transmission, which may enable a more dynamic channel / interference hypothesis for non-coherent joint transmission (NCJT) covering both Frequency Range 1 (FR1) and / or Frequency Range 2 (FR2). As can be understood in the context of multi-TRP, NCJT may refer to transmissions performed by coordinated TRPs without prior phase mismatch correction and tight synchronization. In NCJT, a receiving device may combine transmitted transmissions received non-coherently (i.e., without knowing the phase shift between channels).

[0003] In accordance with the Release 16 specification for multiple transmit-receive point (M-TRP) scenarios, a spatial division multiplexed (SDM) NCJT scheme may provide different layers of the same codeword corresponding to different TRPs or panels, which may imply different Transmission Configuration Information (TCI) states. Accurate measurement and reporting of Channel State Information (CSI) (including channel quality indicator (CQI), rank indicator (RI), precoding matrix indicator (PMI), etc.) for NCJT with a single reporting setting may be subject to efficient configuration and interpretation of CSI resources for channel and interference measurements. [Overview of the project]

[0004] Methods and apparatus for measuring joint channel state information (CSI) are described herein. The method may include receiving channel state information reference signals (CSI-RS) from first and second transmit / receive points (TRPs), determining the CSI, selecting one of the TRPs as the primary TRP, and selecting the remaining one of the first or second TRPs as the secondary TRP. The method may include reporting information indicating the first CSI for the primary TRP, and receiving the second CSI-RS from the TRP. The method may include determining the second CSI and precoding matrix indicator (PMI) for the primary TRP, and determining channel coding information for the primary TRP. The method may include determining the second CSI for the secondary TRP, determining it based on channel coding information, the second CSI for the secondary TRP, and the PMI for the secondary TRP, and reporting information indicating the PMI for the second TRP. [Brief explanation of the drawing]

[0005] A more detailed understanding can be obtained from the following description, which is given as an example in conjunction with the attached drawings, where similar reference numbers in the drawings indicate similar elements. [Figure 1A] This is a system diagram showing an exemplary communication system in which one or more disclosed embodiments may be implemented. [Figure 1B] This is a system diagram showing an exemplary wireless transmit / receive unit (WTRU) that may be used in the communication system shown in Figure 1A, according to one embodiment. [Figure 1C] This is a system diagram showing an exemplary radio access network (RAN) and an exemplary core network (CN) that may be used in the communication system shown in Figure 1A according to one embodiment. [Figure 1D] This is a system diagram showing further exemplary RAN and further exemplary CN that may be used in the communication system shown in Figure 1A according to one embodiment. [Figure 2] This document outlines the procedure for associating a precoder with a single CSI report in CSI measurements for MTRP NCJT. [Figure 3A] This flowchart illustrates the generalized steps of a procedure that may be performed by a device operating in a multi-TRP system to receive CSI-RS, measure and report CSI. [Figure 3B] This diagram illustrates signal transmission that can be performed by devices operating in a multi-TRP system, where CSI-RS is transmitted and CSI is measured and reported. [Figure 4] This figure illustrates an exemplary solution that utilizes angular reciprocity from a sounding reference signal (SRS) when measuring CSI for MTRP NCJT using a single CSI report. [Figure 5] This diagram illustrates an example of the basic operations for enhancing the reliability of PDCCH through iteration. [Figure 6A] This diagram illustrates another example of PDCCH reinforcement, which occurs through linked iterations of PDCCH candidates. [Figure 6B] This diagram illustrates another example of PDCCH reinforcement, which occurs through linked iterations of PDCCH candidates. [Modes for carrying out the invention]

[0006] Figure 1A shows an exemplary communication system 100 in which one or more disclosed embodiments may be implemented. The communication system 100 may be a multiple access system that provides content such as voice, data, video, message transmission, and broadcast to multiple wireless users. The communication system 100 may enable multiple wireless users to access such content through the sharing of system resources, including wireless bandwidth. For example, the communication system 100 may use one or more channel access methods such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), zero-tail unique-word discrete Fourier transform spread OFDM (ZT-UW-DFT-S-OFDM), unique word OFDM (UW-OFDM), resource block filter OFDM, and filter bank multicarrier (FBMC).

[0007] As shown in Figure 1A, the communication system 100 may include radio transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, a radio access network (RAN) 104, a core network (CN) 106, a public switched telephone network (PSTN) 108, the internet 110, and other networks 112, but it will be understood that the disclosed embodiments intend any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, and 102d may be any type of device configured to operate and / or communicate in a radio environment. For example, WTRU102a, 102b, 102c, and 102d, all of which may be referred to as stations (STA), may be configured to transmit and / or receive radio signals and may include user equipment (UE), mobile stations, fixed or mobile subscriber units, subscriber-based units, pagers, mobile 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 wearables, 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 an industrial and / or automated processing chain context), consumer electronic devices, and devices operating on commercial and / or industrial wireless networks. Any of WTRU102a, 102b, 102c, and 102d may interchangeably be referred to as UE.

[0008] The communication system 100 may also include base stations 114a and / or base stations 114b. Each of the base stations 114a and 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, and 102d to facilitate access to one or more communication networks such as CN 106, the Internet 110, and / or other networks 112. As an example, base stations 114a and 114b may be next-generation node B such as base transceiver station (BTS), node B, eNode B (eNB), home node B, home eNode B, gNode B (gNB), new radio (NR) node B, site controller, access point (AP), wireless router, etc. Although base stations 114a and 114b are shown as single elements, it will be understood that base stations 114a and 114b may include any number of interconnected base stations and / or network elements.

[0009] Base station 114a may be part of RAN 104, which may also include other base stations such as a base station controller (BSC), a radio network controller (RNC), relay nodes, and / or network elements (not shown). 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. Cells may provide coverage of radio services to a particular geographic area which may be relatively fixed or change over time. Cells may be further divided into cell sectors. For example, a 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 per sector of the cell. In one embodiment, the base station 114a may use multiple-input multiple output (MIMO) technology and may utilize multiple transceivers for each sector of the cell. For example, beamforming may be used to transmit and / or receive signals in a desired spatial direction.

[0010] Base stations 114a and 114b may communicate with one or more WTRUs 102a, 102b, 102c, and 102d via an air interface 116, which may be any suitable radio communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

[0011] More specifically, as described above, the communication system 100 may be a multiple access system and may use one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, and SC-FDMA. For example, base stations 114a of RAN 104 and WTRU 102a, 102b, and 102c may implement radio technologies such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may establish an air interface 116 using wideband CDMA (WCDMA). WCDMA may include communication protocols such as High-Speed ​​Packet Access (HSPA) and / or Advanced HSPA (HSPA+). HSPA may include High-Speed ​​Downlink Packet Access (HSDPA) and / or High-Speed ​​Uplink Packet Access (HSUPA).

[0012] In one embodiment, base stations 114a and WTRUs 102a, 102b, and 102c may implement radio technologies such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish an air interface 116 using Long Term Evolution (LTE) and / or LTE-Advanced (LTE-A) and / or LTE-Advanced Pro (LTE-A Pro).

[0013] In one embodiment, the base station 114a and WTRUs 102a, 102b, and 102c may implement radio technologies such as NR radio access, which may establish an air interface 116 using NR.

[0014] In one embodiment, base station 114a and WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, base station 114a and WTRUs 102a, 102b, 102c may implement LTE radio access and NR radio access together, for example, using the dual connectivity (DC) principle. Accordingly, the air interfaces utilized by WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technology and / or transmissions sent to / from multiple types of base stations (e.g., eNBs and gNBs).

[0015] In other embodiments, base station 114a and WTRUs 102a, 102b, 102c may implement wireless technologies such as IEEE 802.11 (i.e., Wireless Fidelity (WiFi)), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), etc.

[0016] The base station 114b in Figure 1A may be, for example, a wireless router, home node B, home e-node B, or access point, and may utilize any suitable RAT to facilitate wireless connectivity in local areas such as offices, homes, vehicles, campuses, industrial facilities, aerial corridors (for use by drones), roads, etc. In one embodiment, the base station 114b and WTRU 102c, 102d may implement wireless technologies such as IEEE 802.11 to establish a wireless local area network (WLAN). In one embodiment, the base station 114b and WTRU 102c, 102d may implement wireless technologies such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, base stations 114b and WTRUs 102c, 102d may establish picocells or femtocells using cellular-based RATs (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.). As shown in Figure 1A, base station 114b may have a direct connection to the internet 110. Therefore, base station 114b may not need to access the internet 110 via CN 106.

[0017] RAN 104 can communicate with CN 106, which can be any type of network configured to provide voice, data, applications, and / or voice over internet protocol (VoIP) services to one or more of WTRUs 102a, 102b, 102c, 102d. The data can have various 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, mobile location-based services, prepaid calls, internet connectivity, video delivery, etc., and / or implement high-level security functions such as user authentication. Although not shown in FIG. 1A, it will be understood that RAN 104 and / or CN 106 can communicate directly or indirectly with other RANs using the same RAT or a different RAT as RAN 104. For example, in addition to being connected to RAN 104 that can utilize NR radio technology, CN 106 can also communicate with another RAN (not shown) using GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0018] CN106 may also function as a gateway to WTRU102a, 102b, 102c, and 102d for access to PSTN108, the Internet 110, and / or other networks 112. PSTN108 may include a public switched telephone network providing plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices, which use common communication protocols such as the transmission control protocol (TCP), the user datagram protocol (UDP), and / or the Internet protocol (IP) of the TCP / IP Internet Protocol suite. Network 112 may include wired and / or wireless networks owned and / or operated by other service providers. For example, network 112 may include another CN connected to one or more RANs that may use the same RAT as RAN104 or a different RAT.

[0019] Some or all of the WTRUs 102a, 102b, 102c, and 102d in the communication system 100 may include multimode capability (for example, WTRUs 102a, 102b, 102c, and 102d may include multiple transceivers for communicating with different radio networks via different radio links). For example, WTRU 102c shown in Figure 1A may be configured to communicate with base station 114a, which may use cellular-based radio technology, and base station 114b, which may use IEEE 802 radio technology.

[0020] Figure 1B is a system diagram showing an exemplary WTRU102. As shown in Figure 1B, the WTRU102 may include, among other things, a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power supply 134, a global positioning system (GPS) chipset 136, and / or other peripherals 138. It will be understood that the WTRU102 may include any partial combination of the aforementioned elements while maintaining consistency with one embodiment.

[0021] The processor 118 may be a general-purpose processor, a dedicated 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. The processor 118 may perform signal coding, data processing, power control, input / output processing, and / or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to a transceiver 120 which can be coupled to a transmission / reception element 122. Figure 1B shows the processor 118 and transceiver 120 as separate components, but it will be understood that the processor 118 and transceiver 120 may be integrated together in an electronic package or chip.

[0022] The transmit / receive element 122 may be configured to transmit signals to or receive signals from a base station (e.g., base station 114a) via the air interface 116. For example, in one embodiment, the transmit / receive element 122 may be an antenna configured to transmit and / or receive RF signals. In one embodiment, the transmit / receive element 122 may be an emitter / detector configured to transmit and / or receive, for example, IR, UV, or visible light signals. In yet another embodiment, the transmit / receive element 122 may be configured to transmit and / or receive both RF signals and optical signals. It will be understood that the transmit / receive element 122 may be configured to transmit and / or receive any combination of radio signals.

[0023] Although the transmit / receive element 122 is shown as a single element in Figure 1B, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may utilize MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving radio signals via the air interface 116.

[0024] The transceiver 120 may be configured to modulate the signal transmitted by the transmission / receiving element 122 and to demodulate the signal received by the transmission / receiving element 122. As described above, the WTRU 102 may have multimode capability. Therefore, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11.

[0025] The processor 118 of the WTRU102 may be coupled to a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light-emitting diode (OLED) display unit) and may receive user input from these. The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. In addition, the processor 118 may access information from any type of suitable memory, such as non-removable memory 130 and / or removable memory 132, and may store data in memory. The non-removable memory 130 may include random-access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, and the like. In other embodiments, the processor 118 may access information from memory not physically located on the WTRU 102, such as on a server or home computer (not shown), and store data in memory.

[0026] The processor 118 may receive power from the power supply 134, but 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 supplying power to the WTRU 102. For example, the power supply 134 may include one or more dry cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion), etc.), a solar cell, a fuel cell, etc.

[0027] 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 the air interface 116 and / or determine its location based on the timing of signals received from two or more nearby base stations. It will be understood that the WTRU 102 may acquire location information by any preferred location determination method while maintaining consistency with one embodiment.

[0028] The processor 118 may be further coupled to other peripherals 138, which may include one or more software and / or hardware modules that provide additional features, functions, and / or wired or wireless connectivity. For example, peripherals 138 may include an accelerometer, an electronic compass, a satellite transceiver, a digital camera (for photos and / or videos), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands-free headset, a Bluetooth® module, a frequency modulated (FM) radio unit, a digital music player, a media player, a video game player module, an internet browser, a virtual reality and / or augmented reality (VR / AR) device, an activity tracker, and the like. Peripherals 138 may include one or more sensors. The sensor may be one or more of the following: gyroscope, accelerometer, Hall effect sensor, magnetometer, orientation sensor, proximity sensor, temperature sensor, time sensor, geolocation sensor, altimeter, light sensor, touch sensor, barometer, gesture sensor, biometric sensor, humidity sensor, etc.

[0029] WTRU102 may include a full-duplex radio in which the transmission and reception of some or all of a signal (for example, associated with specific subframes of both UL (for example, for transmission) and DL (for example, for reception) may occur simultaneously and / or together. The full-duplex radio may include an interference management unit for reducing and / or substantially eliminating self-interference via hardware (e.g., chokes) or signal processing via a processor (e.g., via a separate processor (not shown) or processor 118). In one embodiment, WTRU102 may include a half-duplex radio for the transmission and reception of some or all of a signal (for example, associated with specific subframes of either UL (for example, for transmission) or DL ​​(for example, for reception)).

[0030] Figure 1C is a system diagram illustrating RAN104 and CN106 according to one embodiment. As described above, RAN104 can communicate with WTRU102a, 102b, and 102c via the air interface 116 using E-UTRA wireless technology. RAN104 can also communicate with CN106.

[0031] RAN104 may include e-nodes B160a, 160b, and 160c, but it will be understood that RAN104 may include any number of e-nodes B while maintaining consistency with one embodiment. Each of e-nodes B160a, 160b, and 160c may include one or more transceivers for communicating with WTRU102a, 102b, and 102c via the air interface 116. In one embodiment, e-nodes B160a, 160b, and 160c may implement MIMO technology. Thus, e-node B160a may, for example, use multiple antennas to transmit radio signals to and / or receive radio signals from WTRU102a.

[0032] Each of the e-nodes B160a, 160b, and 160c may be associated with a specific cell (not shown) and may be configured to handle wireless resource management decisions, handover decisions, user scheduling, etc., in UL and / or DL. As shown in Figure 1C, the e-nodes B160a, 160b, and 160c may communicate with each other via the X2 interface.

[0033] The CN106 shown in Figure 1C may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (PGW) 166. Although these elements are shown as part of CN106, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0034] The MME162 can be connected to each of the e-nodes B162a, 162b, and 162c in RAN104 via the S1 interface and can function as a control node. For example, the MME162 may perform roles such as authenticating users of WTRU102a, 102b, and 102c, activating / deactivating bearers, and selecting gateways for specific services during the initial attachment of WTRU102a, 102b, and 102c. The MME162 may provide control plane functionality for switching between RAN104 and other RANs (not shown) employing other radio technologies such as GSM and / or WCDMA.

[0035] The SGW164 can be connected to each of the e-nodes-B160a, 160b, and 160c in RAN104 via the S1 interface. The SGW164 can generally route and forward user data packets to and from WTRU102a, 102b, and 102c. The SGW164 can perform other functions, such as anchoring the user plane during e-node-B handovers, triggering paging when DL data is available to WTRU102a, 102b, and 102c, and managing and remembering the context of WTRU102a, 102b, and 102c.

[0036] SGW164 may be connected to PGW166, which may provide WTRU102a, 102b, and 102c with access to a packet-switched network such as the Internet 110 to facilitate communication between WTRU102a, 102b, and 102c and IP-enabled devices.

[0037] CN106 can facilitate communication with other networks. For example, CN106 can provide WTRU102a, 102b, and 102c with access to a circuit-switched network such as PSTN108 to facilitate communication between WTRU102a, 102b, and 102c and conventional terrestrial line communication devices. For example, CN106 may include, or communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that acts as an interface between CN106 and PSTN108. In addition, CN106 may provide WTRU102a, 102b, and 102c with access to another network 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0038] Although the WTRU is shown as a wireless terminal in Figures 1A to 1D, in certain representative embodiments, such a terminal is intended to be able to use a wired communication interface (e.g., temporary or permanent) with a communication network.

[0039] In a typical embodiment, the other network 112 may be a WLAN.

[0040] A WLAN in Basic Service Set (BSS) mode may have access points (APs) of the BSS and one or more stations (STAs) associated with the APs. APs may have access to or interfaces with a Distribution System (DS) or another type of wired / wireless network that carries traffic within and / or outside the BSS. Traffic originating outside the BSS and destined for an STA may reach and be delivered to the STA via an AP. Traffic originating from an STA to a destination outside the BSS may be sent to an AP and then delivered to its respective destination. Traffic between STAs within the BSS may be transmitted, for example, via an AP; a source STA may send traffic to an AP, and the AP may deliver the traffic to the destination STA. Traffic between STAs within the BSS may be considered and / or referred to as peer-to-peer traffic. Peer-to-peer traffic may be transmitted between a source STA and a destination STA (for example, directly between them) via a direct link setup (DLS). In certain representative embodiments, the DLS may use 802.11e DLS or 802.11z tunneled DLS (TDLS). A WLAN using Independent BSS (IBSS) mode may not have APs, and STAs within or using IBSS (e.g., all STAs) may communicate directly with each other. The IBSS mode of communication may be referred to herein as “ad hoc” communication mode.

[0041] When using the 802.11ac infrastructure operating mode or a similar operating mode, an AP may transmit beacons on a fixed channel, such as the primary channel. The primary channel may have a fixed width (e.g., a 20 MHz bandwidth) or a dynamically set width. The primary channel may be the operating channel of the BSS and may be used by the STA to establish a connection with the AP. In certain typical embodiments, Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA) may be implemented, for example, in an 802.11 system. In the case of CSMA / CA, the STA, including the AP (e.g., all STAs), may sense the primary channel. If the primary channel is sensed / detected and / or determined to be busy by a particular STA, that STA may be backed off. A single STA (e.g., only one station) may transmit at any given time on a given BSS.

[0042] High-throughput (HT) STAs may use a 40 MHz wide channel for communication, which may be formed, for example, through a combination of a primary 20 MHz channel and adjacent or non-adjacent 20 MHz channels.

[0043] Very High Throughput (VHT) STAs can support channels with widths of 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz. The 40 MHz and / or 80 MHz channels can be formed by combining consecutive 20 MHz channels. A 160 MHz channel can be formed by combining eight consecutive 20 MHz channels, or by combining two non-contiguous 80 MHz channels, which may be referred to as an 80+80 configuration. In the 80+80 configuration, after channel coding, the data can pass through a segment parser that can split the data into two streams. Inverse Fast Fourier Transform (IFFT) and time-domain processing can be performed separately for each stream. The streams may be mapped to two 80 MHz channels, and the data can be transmitted by a transmitting STA. At the receiver of a receiving STA, the operation described above for the 80+80 configuration may be reversed, and the combined data may be transmitted to Medium Access Control (MAC).

[0044] Sub-1 GHz operating modes are supported by 802.11af and 802.11ah. Channel operating bandwidth and carrier are reduced in 802.11af and 802.11ah compared to those used in 802.11n and 802.11ac. 802.11af supports bandwidths of 5 MHz, 10 MHz, and 20 MHz in the TV White Space (TVWS) spectrum, while 802.11ah supports bandwidths of 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz using the non-TVWS spectrum. According to a typical embodiment, 802.11ah may support meter-type control / machine-type communications (MTC), such as MTC devices in a macro coverage area. MTC devices may have certain capabilities, including support for specific and / or limited bandwidths (e.g., support only for that). MTC devices may include batteries with battery life exceeding a threshold (e.g., to maintain very long battery life).

[0045] A WLAN system capable of supporting multiple channels and channel bandwidths such as 802.11n, 802.11ac, 802.11af, and 802.11ah includes a channel that can be designated as the primary channel. The primary channel may have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and / or limited by an STA from among all STAs operating in a BSS that support the minimum bandwidth operating mode. In the 802.11ah example, the primary channel may be 1 MHz wide for an STA (e.g., an MTC type device) that supports (e.g., only) the 1 MHz mode, even if other STAs in the AP and BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and / or other channel bandwidth operating modes. Carrier sensing and / or Network Allocation Vector (NAV) settings may depend on the state of the primary channel. For example, if the primary channel is busy, an STA (which only supports 1MHz operating mode) sending to the AP may consider the entire available frequency band to be busy, even if most of the available frequency band is idle.

[0046] In the United States, the available frequency band that can be used by 802.11ah is 902MHz to 928MHz. In South Korea, the available frequency band is 917.5MHz to 923.5MHz. In Japan, the available frequency band is 916.5MHz to 927.5MHz. The total bandwidth available for 802.11ah is 6MHz to 26MHz, depending on the country code.

[0047] Figure 1D is a system diagram illustrating RAN104 and CN106 according to one embodiment. As described above, RAN104 can communicate with WTRU102a, 102b, and 102c via the air interface 116 using NR radio technology. RAN104 can also communicate with CN106.

[0048] RAN104 may include gNB180a, 180b, and 180c, but it will be understood that RAN104 may include any number of gNBs while maintaining consistency with one embodiment. Each of gNB180a, 180b, and 180c may include one or more transceivers for communicating with WTRU102a, 102b, and 102c via the air interface 116. In one embodiment, gNB180a, 180b, and 180c may implement MIMO technology. For example, gNB180a and 180b may use beamforming to transmit and / or receive signals to gNB180a, 180b, and 180c. Thus, gNB180a may, for example, use multiple antennas to transmit and / or receive radio signals from WTRU102a. In one embodiment, gNB180a, 180b, and 180c may implement carrier aggregation technology. For example, gNB180a may transmit multiple component carriers to WTRU102a (not shown). A subset of these component carriers may be on the unauthorized spectrum, and the remaining component carriers may be on the authorized spectrum. In one embodiment, gNB180a, 180b, and 180c may implement coordinated multi-point (CoMP) technology. For example, WTRU102a may receive coordinated transmissions from gNB180a and gNB180b (and / or gNB180c).

[0049] WTRU102a, 102b, and 102c may communicate with gNB180a, 180b, and 180c using transmissions associated with an expandable numerology. For example, OFDM symbol intervals and / or OFDM subcarrier intervals may vary for different transmissions, different cells, and / or different portions of the radio transmission spectrum. WTRU102a, 102b, and 102c may communicate with gNB180a, 180b, and 180c using subframes or transmission time intervals (TTIs) of varying or expandable lengths (e.g., varying numbers of OFDM symbols and / or varying durations of absolute time).

[0050] gNB180a, 180b, and 180c can be configured to communicate with WTRU102a, 102b, and 102c in standalone and / or non-standalone configurations. In a standalone configuration, WTRU102a, 102b, and 102c can communicate with gNB180a, 180b, and 180c without accessing other RANs (e.g., e-nodes B160a, 160b, and 160c). In a standalone configuration, WTRU102a, 102b, and 102c can utilize one or more of gNB180a, 180b, and 180c as mobility anchor points. In a standalone configuration, WTRU102a, 102b, and 102c can communicate with gNB180a, 180b, and 180c using signals in unlicensed bands. In a non-standalone configuration, WTRU102a, 102b, and 102c can communicate with and connect to gNB180a, 180b, and 180c, while also communicating with and connecting to other RANs such as enodes B160a, 160b, and 160c. For example, WTRU102a, 102b, and 102c can implement DC principles for substantially simultaneous communication with one or more gNB180a, 180b, and 180c and one or more enodes B160a, 160b, and 160c. In a non-standalone configuration, e-nodes B160a, 160b, and 160c can function as mobility anchors for WTRU102a, 102b, and 102c, while gNB180a, 180b, and 180c can provide additional coverage and / or throughput to service WTRU102a, 102b, and 102c.

[0051] Each of the gNB180a, 180b, and 180c may be associated with a specific cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, network slice support, interaction between DC, NR and E-UTRA, routing of user plane data to User Plane Functions (UPFs) 184a and 184b, routing of control plane information to Access and Mobility Management Functions (AMFs) 182a and 182b, and so on. As shown in Figure 1D, the gNB180a, 180b, and 180c may communicate with each other via the Xn interface.

[0052] The CN106 shown in Figure 1D may include at least one AMF182a, 182b, at least one UPF184a, 184b, at least one Session Management Function (SMF)183a, 183b, and possibly a Data Network (DN)185a, 185b. Although the aforementioned elements are shown as part of CN106, it will be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0053] AMF182a and 182b can be connected to one or more of gNB180a, 180b, and 180c in RAN104 via the N2 interface and can function as control nodes. For example, AMF182a and 182b may play roles such as user authentication for WTRU102a, 102b, and 102c, support for network slicing (e.g., handling different protocol data unit (PDU) sessions with different requirements), selection of SMF183a and 183b for registration, management of registration areas, termination of non-access stratum (NAS) signaling, and mobility management. Network slicing can be used by AMF182a and 182b to customize CN support for WTRU102a, 102b, and 102c based on the type of service utilizing WTRU102a, 102b, and 102c. For example, different network slices may be established for different use cases, such as services that rely on ultra-reliable low latency (URLLC) access, services that rely on enhanced massive mobile broadband (eMBB) access, and services for MTC access. AMF182a, 182b may provide control plane functionality for switching between RAN104 and other RANs (not shown) using other radio technologies such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies such as WiFi.

[0054] SMF183a and 183b may be connected to AMF182a and 182b in CN106 via the N11 interface. SMF183a and 183b may also be connected to UPF184a and 184b in CN106 via the N4 interface. SMF183a and 183b may select and control UPF184a and 184b and configure the routing of traffic through UPF184a and 184b. SMF183a and 183b may 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 may be IP-based, non-IP-based, Ethernet-based, etc.

[0055] UPF184a and 184b may be connected via the N3 interface to one or more gNB180a, 180b, and 180c within RAN104, thereby providing WTRU102a, 102b, and 102c with access to a packet-switched network such as the Internet 110 to facilitate communication between WTRU102a, 102b, and 102c and IP-enabled devices. UPF184 and 184b may perform other functions such as packet routing and forwarding, enforcement of user plane policies, support for multi-homed PDU sessions, processing of user plane QoS, buffering of DL packets, and mobility anchoring.

[0056] CN106 can facilitate communication with other networks. For example, CN106 may include, or communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that functions as an interface between CN106 and PSTN108. In addition, CN106 may provide WTRU102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, WTRU102a, 102b, 102c may be connected to local DN185a, 185b via UPF184a, 184b through an N3 interface to UPF184a, 184b and an N6 interface between UPF184a, 184b and DN185a, 185b.

[0057] With regard to Figures 1A-1D and the corresponding descriptions in Figures 1A-1D, one or more of the functions described herein with respect to one or more of the WTRU102a-d, base stations 114a-b, e-nodes B160a-c, MME162, SGW164, PGW166, gNB180a-c, AMF182a-b, UPF184a-b, SMF183a-b, DN185a-b, and / or any other devices described herein may be implemented by one or more emulation devices (not shown). An emulation device may be one or more devices configured to emulate 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.

[0058] Emulation devices may be designed to implement testing of one or more other devices in a laboratory and / or operator network environment. For example, one or more emulation devices may perform one or more or all functions while fully or partially implemented and / or deployed as part of a wired and / or wireless network to test other devices in a communications network. One or more emulation devices may perform one or more or all functions while temporarily implemented / deployed as part of a wired and / or wireless network. Emulation devices may be directly coupled to another device for the purpose of testing and / or performing testing using over-the-air wireless communication.

[0059] One or more emulation devices may perform one or more functions, including all of the above, while not implemented / deployed as part of a wired and / or wireless communication network. For example, an emulation device may be used in a test laboratory test scenario, and / or in a wired and / or wireless communication network that is not deployed (e.g., for testing purposes), to implement testing of one or more components. One or more emulation devices may be test equipment. Direct RF coupling and / or wireless communication via RF circuitry (e.g., which may include one or more antennas) may be used by the emulation device to transmit and / or receive data.

[0060] According to some schemes that the embodiments described herein may cover, it may be possible to have CSI reference signal (RS) resources (e.g., non-zero power (NZP) CSI-RS) for channel measurements associated with different TRP, panel, and / or TCI states at the resource level for CSI measurements in an NCJT having a single reporting setting. Thus, channel measurement resources (CMRs) corresponding to different TRP / panel / TCI states may be configured within the same CSI-RS resource set and may have the same number of CSI-RS ports.

[0061] The question remains whether to use CSI-RS or CSI interference measurement (IM) for interference measurements. Methods for evaluating channel measurements for different TRPs, panels, and / or TCI states, as well as how to correlate CMR and IMR attributes, may be considered.

[0062] As described in the Release 16 specification, underlying problems may exist when establishing CSI measurements for SDM NCJT based on CMR and interference measurement resource (IMR). This may stem from the fact that interlayer interference from another TRP / panel presented by other TCI conditions may not be the same as interference measured using techniques employing CSI-IM or NZP-CSI-RS. Such techniques may result in inaccurate estimations of channel information.

[0063] In an SDM NCJT multi-TRP / panel network, signals can be constrained to a desired subspace through coordinated precoding in the TRP / panel. Therefore, the desired signal can be reconstructed at the receiver as different layers of the same codeword. Instead of treating signals from other TRPs / panels as interference, the signal can be considered in relation to the precoded signal from the primary TRP / panel. Thus, the CSI can be calculated accurately without down-estimation.

[0064] One problem addressed in the following embodiments may be how to measure and report CSI, including PMI, RI, CQI, and other metrics, in order to reduce interlayer interference for NCJT CSI with a single reporting setup.

[0065] Several solutions may provide an association between a precoder and a single reporting configuration in joint CSI measurements for NCJT. In some cases, the WTRU may associate and use the CSI-RS resource signal received from the TRP / panel in joint CSI measurements for NCJT with a single reporting configuration. The WTRU may measure, generate, and report the CSI, specifically the precoder / transmitter filter used in the TRP / panel. Thus, the signal transmitted from the TRP / panel may be received in the WTRU as a transmit layer of the same codeword. The terms precoder and transmit filter may be used interchangeably herein.

[0066] WTRU may measure and report CSI in a single TRP / panel mode or a multi-TRP / panel connection mode, and the Channel Condition Information (CSI) report for each connection mode may include, or be configured with, one or more of the following parameters, rules, or configurations. For example, the configuration for each connection mode may include a CSI reporting configuration (such as aperiodic, semi-permanent, or periodic type), a CSI reporting codebook configuration (e.g., type I, type II, type II port selection), or a CSI reporting frequency, including one or more CSI reporting quantities (such as channel quality indicator (CQI), rank indicator (RI), precoding matrix indicator (PMI), CSI-RS resource indicator (CSI-RS Resource Indicator, CRI), layer indicator (LI)).

[0067] The CSI resources measured in each connection mode may be comprised of a CSI-RS resource set and may include one or more of the following: a CSI-RS resource for channel measurement (e.g., an NZP CSI-RS resource for channel measurement), a CSI-RS resource for interference measurement (e.g., an NZP CSI-RS resource for interference measurement), or a CSI-IM resource for interference measurement.

[0068] The CSI resources measured in each connection mode may include NZP CSI-RS resources, which may be associated with one or more of the following parameters: NZP CSI-RS resource ID, periodicity and offset, QCL information and TCI status, or resource mapping (e.g., number of ports, density, CDM type, etc.).

[0069] In some solutions, the WTRU may be configured with a single CSI reporting configuration having at least one CSI-RS resource set, each CSI-RS resource set may contain at least the same number of CSI-RS resources as the number of TRPs / panels. In some examples, each CSI resource set may contain channel and / or interference measurement resources for each TRP / panel / TCI state.

[0070] In some embodiments, two or more TRP / panels may cooperate when communicating with the WTRU. The scheme provided herein may subsequently provide two TRP / panel systems. However, the methods, procedures, and calculations may be extended to more TRP / panels if necessary.

[0071] In some examples, in two TRP / panel models, the WTRU may be configured with at least one CSI-RS resource set, and each CSI-RS resource set may be configured with at least two CSI-RS resources. In some examples, each CSI resource set may include channel and / or interference measurement resources for each TRP / panel / TCI state.

[0072] A CSI-RS resource set may include at least a first CSI-RS resource corresponding to a first TCI state that can be linked to a first TRP / panel, and at least a second CSI-RS resource corresponding to a second TCI state that can be linked to a second TRP / panel. One or more first CSI-RS resources may be associated with a second CSI-RS resource or resource set.

[0073] Each TRP / panel's corresponding CSI-RS resource set may include one or more CSI-RS resources for channel measurements (e.g., NZP CSI-RS resources). Each TRP / panel's corresponding CSI-RS resource set may also include one or more CSI-RS resources for interference measurements (e.g., NZP CSI-RS resources), and the CSI-RS resources for interference measurements included in the second CSI-RS resource set may be the same as the CSI-RS resources for interference measurements included in the first CSI-RS resource set.

[0074] Alternatively or additionally, the WTRU may receive configuration information indicating multiple coresets and / or search spaces. Each coreset or search space may be configured with or associated with TCI states that can correspond to TRP / panels.

[0075] A WTRU may be configured using at least one set of CSI-RS resources. Each CSI-RS resource set may be configured using a single CSI-RS resource. Therefore, the same set of CSI-RS resources may be used for both TRPs. A WTRU may assume that CSI-RS from the same resource set do not collide in time or frequency. In other words, CSI-RS resources in the same resource set can be orthogonal. When a WTRU monitors the search space, the TCI state corresponding to an received CSI-RS may be determined based on the TCI state configured for that search space. Therefore, the corresponding TRP can be determined.

[0076] In some examples, in a multi-TRP / panel system having three or more TRPs / panels, the WTRU may be configured using at least one set of CSI-RS resources. The CSI-RS resource set may contain at least the same number of CSI-RS resources as the number of TRPs / panels, and one or more of the CSI-RS resources may correspond to one of the TCI states linked to one of the TRPs / panels. One or more CSI-RS resources corresponding to each TRP / panel may include one or more NZP CSI-RS resources for channel measurements. One or more CSI-RS resources corresponding to each TRP / panel may include one or more NZP CSI-RS resources for interference measurements. NZP CSI-RS resources for interference measurements corresponding to different TRPs / panels may be associated in pairs or in a one-to-one relationship with each other. An NZP CSI-RS resource for interferometry corresponding to a CSI-RS resource setting linked to a TCI state / TRP / panel may be the same as an NZP CSI-RS resource for interferometry corresponding to a CSI-RS resource linked to another TCI state / TRP / panel.

[0077] In some solutions, the WTRU may receive information that triggers or activates a multi-TRP / panel CSI reporting configuration. The WTRU may measure and report CSI in two consecutive reporting modes, namely a single-TRP / panel reporting mode and a multi-TRP / panel reporting mode.

[0078] Several procedures described herein may define a two-step CSI measurement process for MTRP NCJT transmission. In a procedure that may be implemented in a WTRU, each step may include two events: reception of the CSI-RS and reporting of the CSI.

[0079] In the first step, a first TRP (i.e., TRP1) may be configured to transmit a first CSI-RS (e.g., NZP CSI-RS), and a second TRP (i.e., TRP2) may be configured to transmit a second CSI-RS (e.g., NZP CSI-RS). The WTRU may receive the first and second NZP CSI-RS from the first and second TRPs according to their corresponding configured TCI information. The WTRU may receive each of the NZP CSI-RS according to their time / frequency configurations. The WTRU may assume that the received NZP CSI-RS do not collide in time or frequency. In some solutions, the WTRU may be assumed to have multiple CSI-RS resource configurations, each used for a different step. In some solutions, the WTRU may be assumed to employ a single CSI-RS configuration for all steps. Alternatively or additionally, the WTRU may receive a single CSI-RS configuration containing information about two or more CSI-RS resources required for both steps.

[0080] In the second step, the WTRU may report the CSI measurements following the receipt of the NZP CSI-RS. In some solutions, it may be assumed that the WTRU has multiple CSI measurement content configurations and reporting resources, and may use each of the multiple measurement content configurations and / or reporting resources for different steps. In some solutions, the WTRU may employ a single CSI measurement content configuration and reporting resource for all steps. Alternatively or additionally, the WTRU may receive a single configuration for the CSI measurement content and reporting resources, which may contain two or more CSI measurement content and reporting resources required for both steps.

[0081] Figure 2 illustrates an exemplary CSI measurement and reporting process that may be implemented in a system with multiple TRPs. The illustrated procedure may provide a correlation between precoders in CSI measurement for MTRP NCJT and a single CSI report, consistent with at least some of the methods described above.

[0082] The process shown in Figure 2 can be outlined as follows. In the first step 210 of the process, the WTRU may receive CSI-RS transmitted by TRP1 and TRP2 on the first and second CSI-RS resources, respectively. The WTRU may measure the received CSI-RS. Based on the measurements of the received CSI-RS, the WTRU may report a CSI that may include information indicating at least a preferred PMI associated with TRP1. In this step, the CSI-RS received from the second TRP may provide a criterion for determining interference present in the channel carrying the CSI-RS from the first TRP, and such information may be necessary for calculating the PMI for TRP1. In other words, the WTRU may use the CSI-RS received from the second TRP to measure channel characteristics and determine the PMI for TRP1.

[0083] In the second step 220 of the process, the WTRU may perform similar measurements and reports, except for the second TRP. For example, the WTRU may receive CSI-RS transmitted by TRP1 and TRP2, respectively. The WTRU may perform measurements on the received CSI-RS. Based on the measurements performed on the CSI-RS resources for TRP1 and TRP2, the WTRU may report a CSI that includes information indicating at least a preferred PMI for TRP2. Here, the CSI-RS received from TRP1 in step 220 may provide a criterion for determining interference present in the channel carrying the CSI-RS from the second TRP, and such information may be necessary for calculating the PMI for TRP2. In this step, the WTRU that reported the CSI to TRP1 in the previous step 210 (including, for example, an indication of a preferred PMI) may assume that the CSI-RS received from TRP1 is precoded based on the PMI determined for TRP1 (e.g., PMI-1). Therefore, when calculating the preferred PMI for TRP2, WTRU may emulate or take into account interlayer interference based on the CSI-RS and associated PMI measurements from TRP1 determined in step 210.

[0084] Figures 3A and 3B are flowcharts and diagrams illustrating exemplary procedures for multi-TRP CSI estimation and reporting, respectively. Several steps consistent with the illustrated procedures can be summarized as follows:

[0085] Figures 3A and 3B illustrate the procedures that may be performed by a device operating in a multi-TRP system to receive CSI-RS, measure and report CSI. While the device operating in the multi-TRP system may be a WTRU, as described in the following paragraphs, it should be understood that the corresponding procedures may be performed by a base station, network node, node B, TRP, AP, STA, or UE.

[0086] Figure 3A illustrates the generalized steps of the procedure, and Figure 3B illustrates the signaling of relevant system participants performing the steps according to the generalized procedure outlined in Figure 3A. As generally described in the paragraph above, although not shown in Figure 3A or Figure 3B, a WTRU performing the described procedure may first receive configuration information indicating a resource for receiving CSI-RS. The CSI-RS resource may carry CSI-RS that can be used to calculate channel interference and inter-layer interference between the system's TRPs. Subsequently received CSI-RS may be different CSI-RS and may be orthogonal to each other. The CSI-RS may be NZP CSI-RS.

[0087] As shown in Figure 3A, in 310, the WTRU may receive one or more first CSI-RSs from a first TRP (i.e., TRP1) and a second TRP (i.e., TRP2) for channel measurement and transmit reports containing the first CSI quantity and the second CSI quantity, respectively, to the primary TRP. The first CSI-RSs may be used for measuring or estimating the channels on which TRP1 and TRP2 operate. Referring to Figure 3B, each of the one or more first CSI-RSs is indicated by elements 311 and 312. Based on the one or more first CSI-RSs received, the WTRU may measure and determine the respective first CSI quantities of TRP1 and TRP2. The WTRU may select either TRP1 or TRP2 as the primary TRP, and the other TRP as the secondary TRP. The selection may also be based on a first CSI quantity for TRP1 and TRP2, which may include one or more of the following: reference signal received power (RSRP), signal-to-interference ratio (SINR), or channel quality indicator (CQI). The selection based on the first CSI quantity may further be based on a threshold (i.e., a comparison of one or both CSI quantities with an absolute or relative threshold). As shown in 313 of Figure 3B, a report may be transmitted that includes at least the first CSI quantity determined for the primary TRP. A device receiving the report (e.g., a primary TRP, base station, or network node, and / or possibly a secondary TRP) may recognize the selection of the primary TRP. For example, a CSI resource indicator may be included in the report and may be an implicit indication of the selection.

[0088] As shown in 320, the WTRU may receive one or more second CSI-RSs (321 and 322, respectively, shown in Figure 3B) from the primary TRP and from the secondary TRP. The CSI-RS 321 received from the primary TRP may be precoded based on the CSI reported for the primary TRP in step 310 and may be used to measure or estimate interlayer interference between TRP1 and TRP2. The CSI-RS 322 received from the secondary TRP may be used to measure or estimate the channel on which TRP2 operates. Based on the one or more second CSI-RSs received from the primary TRP, the WTRU may determine a second CSI quantity and / or PMI for the primary TRP. The WTRU may also determine channel coding parameters (e.g., the zero space of the channel matrix) associated with the one or more second CSI-RSs received from the primary TRP. As shown in 323, the WTRU may report a second CSI amount and / or PMI for the primary TRP determined based on the received CSI-RS 321.

[0089] As shown in 330, the WTRU may determine a second CSI quantity for the secondary TRP based on CSI-RS 322. Based on the determined channel coding parameters (i.e., the determined zero space such that the preferred precoding matrix indicated by the PMI lies in the zero space of the channel matrix associated with the primary TRP) and the determined second CSI quantity for the secondary TRP, the WTRU may determine the PMI for the secondary TRP (i.e., the preferred PMI). The WTRU may report the determined PMI for the secondary TRP. The determined PMI may be such that inter-layer interference between the primary and secondary TRPs is minimized.

[0090] Further details regarding the single TRP / panel reporting mode are described herein. In the single TRP / panel reporting mode, the WTRU may independently and separately measure and report the CSI corresponding to the TRP / panel based on the CSI-RS for channel measurement. The procedure may include one or more of the following procedures or conditions.

[0091] For example, a WTRU may receive CSI-RS from the first TRP and the second TRP. The WTRU may use the received CSI-RS for channel measurement of the TRP / panel. The CSI-RS for channel measurement may be different and orthogonal. The WTRU may measure the CSI of each TRP / panel separately. The WTRU may select one of the TRP / panels as the primary TRP / panel and the other as the secondary TRP / panel. The WTRU may measure the CSI quantities corresponding to the primary TRP / panel, including RI and PMI, and report the CSI corresponding to the primary TRP / panel to a network node (e.g., TRP, base station, node B, or another device).

[0092] With regard to the selection of primary or secondary TRPs / panels, the WTRU may select TRPs / panels based on different sets of parameters. In some examples, the WTRU may be configured with instructions from a base station, node B, or other network nodes (e.g., through RRC message transmission, MAC CE, or any logically equivalent message) indicating which TRP / panel should be selected as the primary TRP and which TRP or panel should be selected as the secondary TRP. In some examples, the WTRU may select the primary TRP / panel based on higher L1-RSRP, L1-SINR, CQI, and / or according to predetermined / configured thresholds.

[0093] Further details regarding the multi-TRP / panel reporting mode are described herein. In procedures involving two or more steps, this mode may follow the single-TRP / panel reporting mode. Based on the CSI reported by the WTRU operating in single-TRP / panel reporting mode, a network node (e.g., TRP, base station, node B, or another device) may determine the precoder / transmitter filter to be used for the transmit layer corresponding to the primary TRP / panel. The network node may use this precoder / transmitter filter for transmitting the CSI-RS from the primary TRP / panel in multi-TRP / panel reporting mode (or may transmit configuration information indicating the use of the determined precoder / transmitter filter).

[0094] In multi-TRP / panel reporting mode, the procedure may include one or more of the following conditions or procedures. For example, the WTRU may receive a precoded CSI-RS (e.g., NZP CSI-RS) from the primary TRP / panel, which is precoded based on PMIs previously and during single-TRP / panel reporting mode. The received precoded CSI-RS may be used to measure interference between the primary TRP / panel and the secondary TRP / panel. For example, based on the technical specification of Release 16, the WTRU may assume that the CSI-RS configured for interference measurement corresponds to the transmit layer.

[0095] The WTRU can also receive CSI-RS, which is used for channel measurements, from the secondary TRP / panel.

[0096] The WTRU may determine the precoder / transmitter filters used in the first and second TRP / panels. The WTRU may measure the CSI and, specifically, determine the PMI for the primary TRP / panel based on the corresponding CSI-RS resources for interference measurements. The WTRU may measure the CSI for the secondary TRP / panel based on the corresponding CSI-RS used for channel measurements. The WTRU may select the PMI for the secondary TRP / panel based on the zero space of the precoded CSI-RS received from the primary TRP / panel. In the process of measuring the CSI for the secondary TRP / panel, the WTRU may consider the precoded signal received from the primary TRP / panel as another layer of the same codeword in NCJT.

[0097] In other words, the WTRU can be considered as the basis for calculating the CSI / PMI for the secondary TRP / panel, as if the signals received from the primary TRP / panel were transmitted from the secondary TRP / panel. The WTRU can be used to determine the concatenated PMI for the secondary TRP / panel, which is consistent with the TCI state of the secondary TRP / panel, oriented along the beam carrying the signals from the secondary TRP / panel, and orthogonal to the signals received from the primary TRP / panel. The formulation can be provided as follows, based on the zero space of precoding matrices selected based on the precoded CSI-RS received from the first TRP / panel:

[0098] At the end of the procedure performed in multi-TRP / panel reporting mode, a network node (e.g., one TRP (primary TRP and / or secondary TRP, etc.), a base station, node B, or another device) may have access to both single TRP / panel CSIs and multi-TRP / panel CSIs from the WTRU. Thus, switching between single-TRP / panel and multi-TRP / panel methods at a network node can be achieved dynamically based on the provided CSI reports.

[0099] In some solutions, the multi-TRP / panel reporting mode can be used independently of the single-TRP / panel reporting mode. For example, the WTRU may determine the PMI for the CSI-RS for TRP1 (i.e., PMI-1) in the multi-TRP / panel reporting mode, and then determine the PMI for the CSI-RS for TRP2 (i.e., PMI-2) using emulated interference based on the CSI-RS for TRP1 and its associated PMI. One or more of the following conditions or procedures may apply.

[0100] For example, a WTRU may report both PMI-1 and PMI-2 in a single CSI report with associated CQI and RI. One or more PMI-1s may be determined or selected by the WTRU. For example, a WTRU may select and / or determine the PMI-1 with the best M (e.g., M≧1) that can provide the highest observed CQI value for a given channel state measured from the CSI-RS received from the TRP-1. When two or more PMI-1s are selected, determined, or used, the WTRU may also select / determine a PMI-2 for each PMI-1 value. As a result, M sets of PMI-1 and PMI-2 values ​​may be selected or determined. A WTRU may report M sets of PMI values ​​(PMI-1, PMI-2) and their associated CQI and / or RI. When a single PMI-1 is selected, determined, or used, the WTRU may select or determine a single PMI-2 based on the determined PMI-1. The Mth value may be determined based on at least one of the following: the number of TRPs / panels configured for multi-TRP / panel reporting mode, the number of CSI-RS resources for channel measurement in the associated CSI resource configuration, configuration information provided in messages from network nodes (e.g., RRC messages, MAC-CE, or other logically equivalent messages), reporting channel capacity (e.g., number of bits available for reporting), channel quality metrics (e.g., SINR range, RSRP range, CQI, RI, etc.), or WTRU capability.

[0101] In some solutions, one or more multi-TRP / panel reporting modes may be used, configured, or defined. For example, a first multi-TRP / panel reporting mode (e.g., a Type 1 multi-TRP / panel reporting mode) may be based on CSI reporting for each TRP / panel without sequential PMI decisions / selections for emulated interference (e.g., inter-layer interference). A second multi-TRP / panel reporting mode (e.g., a Type 2 multi-TRP / panel reporting mode) may be based on CSI reporting for multiple TRPs / panels with sequential PMI decisions / selections. The type of multi-TRP / panel reporting mode may be determined based on at least one of the following: WTRU capability, configuration information received from network nodes (e.g., RRC messages, MAC-CE, or another logical equivalent), or instructions in trigger DCI (e.g., for aperiodic / semi-persistent reporting).

[0102] Formulas that may be used throughout the embodiments are described. To calculate the optimal precoder linked to the secondary TRP / panel, the precoder may be associated with the zero space of the primary TRP / panel.

[0103] The procedure for determining the secondary PMI in multi-TRP / panel reporting mode may be carried out according to one or more of the following rules or criteria. For example, the procedure may take into account the TCI status associated with the secondary TRP / panel and one or more corresponding channel coding parameters (e.g., H) from the primary TRP / panel and the secondary TRP / panel. P and H S This may include the calculation of the channel matrix (along with other relevant variables). Theoretically, inter-zero layer interference is pre-coded for secondary TRP / panels. P It may be necessary to be in zero space. H P Its rank is R p =rank(H p) may be defined as. Singular value decomposition (SVD) is

[0104]

Math

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[0108] Several solutions may involve joint selection of antenna ports associated with CSI-RS based on UL / DL angular reciprocity. For example, in some cases, the WTRU may employ CSI-RS port selection in joint CSI measurements for NCJT in a single TRP / panel reporting mode in which CSI-RS may be associated. The WTRU may measure CSI based on precoded CSI-RS received from multiple TRPs / panels. For example, in accordance with the technical specifications of Release 16, the WTRU may assume that CSI-RS may be used to measure interference between different transmit layers. The WTRU may select and report the most preferred port pair from the TRPs / panels together.

[0109] A WTRU may measure and report the selection of an antenna port associated with a CSI port selection, and the CSI for each connection mode may include, or be configured with, one or more configurations, parameters, or resources. For example, the CSI may be provided in conjunction with a CSI reporting configuration that includes information indicating one or more of the following: CSI reporting quantities, e.g., channel quality indicator (CQI), rank indicator (RI), precoding matrix indicator (PMI), layer indicator (LI); CSI reporting types, e.g., aperiodic, semi-persistent, or periodic reporting types; CSI reporting codebook configuration (e.g., defined as TypeII-PortSelection or TypeII-PortSelection-r16); or CSI reporting frequency.

[0110] CSI may report resources in a set of CSI-RS resources that include one or more CSI resources, such as NZP CSI-RS resources for channel measurements, NZP CSI-RS resources for interference measurements, or CSI-IM resources for interference measurements.

[0111] CSI may report on CSI-RS resources including one or more of the following: NZP CSI-RS resource ID, periodicity and offset, QCL information and TCI status, or resource mapping such as the number of ports, density, and CDM type.

[0112] In some solutions, a network node (e.g., TRP, base station, node B, or another device) may precode CSI-RS for interference measurement based on UL measurements corresponding to resources for CSI-RS transmission. For example, a WTRU may transmit a sounding reference signal, which may be received by a network node. The network node may measure the SRS received from the WTRU and use the angular reciprocity of UL and DL to determine how to precode the CSI-RS to be transmitted later.

[0113] In two TRP / panel models, the WTRU may be configured with a single CSI reporting configuration having at least one CSI-RS resource set, each CSI-RS resource set including at least two resources for CSI-RS transmission (e.g., for channel and interference measurements for each TRP / panel / TCI state). The CSI-RS resource set may include a first CSI-RS resource corresponding to a first TCI state linked to a first TRP / panel, and a second CSI-RS resource corresponding to a second TCI state linked to a second TRP / panel. The CSI-RS resources corresponding to the first and second TCI states may be associated with each other. The CSI-RS resource corresponding to each TRP / panel may include one or more NZP CSI-RS resources for channel measurements. The CSI-RS resource corresponding to each TRP / panel may include one or more NZP CSI-RS resources for interference measurements.

[0114] CSI-RS resources for channel measurement and interference measurement corresponding to TRP / panels can be paired with each other on a resource-by-resource basis. In other words, a CSI-RS resource for channel measurement for a first TRP / panel can be configured to be the same as a CSI-RS resource for interference measurement for a second TRP / panel. Similarly, a CSI-RS resource for channel measurement for a second TRP / panel can be configured to be the same as a CSI-RS resource for interference measurement for a first TRP / panel.

[0115] Figure 4 shows an exemplary procedure for CSI reporting that utilizes angular reciprocity from SRS measurements.

[0116] Although not shown in Figure 4, it should be understood that the WTRU may receive information that triggers or activates a multi-TRP / panel non-PMI port selection reporting configuration. The procedure for measuring and reporting CSI, as illustrated in Figure 4, may include one or more of the following conditions, steps, or procedures. For example, the WTRU may receive precoded CSI-RS (e.g., NZP CSI-RS) from the TRP / panel. A CSI-RS resource used to carry CSI-RS for channel measurements from a first TRP / panel may be configured as a CSI-RS resource to carry CSI-RS for interference measurements from a second TRP / panel. Similarly, a CSI-RS resource carrying CSI-RS for channel measurements from a second TRP / panel may be configured as a CSI-RS resource carrying CSI-RS for interference measurements from a first TRP / panel. The association between CSI-RS resources may be configured based on the TCI state linked to the TRP / panel.

[0117] The procedure for measuring and reporting CSI, as provided in Figure 4, may involve the WTRU measuring the CSI for all pairs of ports corresponding to the precoded CSI-RS received from the TRP / panel.

[0118] The procedure for measuring and reporting CSI, as provided in Figure 4, may involve the WTRU reporting the most preferred pair of ports corresponding to the precoded CSI-RS received from the TRP / panel.

[0119] Regarding the selection of the most preferred pair, WTRU may select a pair based on a different set of parameters. In some examples, WTRU may select a preferred pair based on signal quality measurements (e.g., L1-RSRP, L1-SINR, CQI) and according to predetermined / configured thresholds.

[0120] The solution shown in Figure 4 may be an exemplary two-step CSI measurement process for M-TRP NCJT transmission. The two-step process can be outlined as follows: In the first step 410, the WTRU may transmit at least one Sounding Reference Signal (SRS) using the configured SRS resources. If the WTRU initiates a single SRS transmission event, the WTRU may use only a single spatial filter that can be defined by the configured spatial relation information. However, if the WTRU transmits two or more SRSs by signals 411 and 412, as shown in step 410, the WTRU may use different spatial filters (i.e., different spatial relation information that may correspond to different TRPs).

[0121] In some solutions, the WTRU may use a specific subset of SRS resources or a set of SRS resources for SRS transmissions in the first step. The WTRU may use a specific subset for triggering CSI-RS transmissions from the TRP, as shown in step 420 and described in further detail herein. In some solutions, when SRS-based CSI acquisition for the M-TRP architecture is activated, the WTRU may always expect to receive CSI-RS from the TRP at a given time and frequency resource. For example, the WTRU may expect to receive CSI-RS at a slot offset from the SRS transmission (e.g., slot n+4, where n is the slot from which the WTRU transmits one or more SRSs) t. Alternatively or additionally, the WTRU may determine whether a requested CSI-RS transmission, as shown in step 420, is implicitly or explicitly available. For example, the WTRU may monitor a dedicated CORESET or search space. On the other hand, the WTRU may receive a DCI or MAC CE, or another logical equivalent, containing information that implicitly or explicitly indicates the transmission of the requested CSI-RS.

[0122] In the second step of process 420, based on measurements performed on the NZP CSI-RS received from the first TRP and the second TRP (shown in Figure 4 by elements 421 and 422), the WTRU may report CSI information for each TRP indicating at least its preferred PMI. In this step, the CSI-RS received from one TRP may be considered as the basis for determining the interlayer interference required for calculating the PMI of the other TRP.

[0123] In some solutions, the second step 420 may include two or more events, such as the WTRU receiving the CSI-RS and the WTRU reporting the CSI.

[0124] In some solutions, upon receiving CSI-RS, the WTRU may receive instructions for a first and second set of NZP CSI-RS resources from a first TRP and a second TRP, according to their corresponding configured TCI information. The WTRU may receive NZP CSI-RS from each TRP according to their time / frequency configurations. The WTRU may assume that the received NZP CSI-RS do not conflict in time or frequency. In some solutions, the WTRU may receive multiple CSI-RS resource configurations from one of the TRPs, which may correspond to different TRPs. For example, the WTRU may receive information indicating the CSI-RS resource configuration via DCI from the primary TRP. In some solutions, the WTRU may receive multiple CSI-RS resource configurations associated with each TRP from these corresponding TRPs, for example, via multiple DCIs.

[0125] In some solutions, for WTRU reporting of CSI, the WTRU may report the CSI measurement following the receipt of the NZP CSI-RS resource. In some solutions, the WTRU may have multiple CSI measurement content configurations and reporting resources, and may use each set of CSI measurement content configurations and reporting resources for different TRPs. In some solutions, the WTRU may employ a single CSI measurement content configuration and reporting resource for all TRPs. Alternatively or additionally, the WTRU may receive information that provides a single configuration for CSI measurement content and reporting resources. This configuration may indicate two or more types of CSI measurement content to be reported and the reporting resources required for both TRPs.

[0126] This specification describes solutions involving dynamic switching between single TRP / panel CSI reporting modes and multiple TRP / panel CSI reporting modes. In some solutions, the WTRU can dynamically switch between multiple CSI reporting types (e.g., between single TRP / panel CSI reporting and multi-TRP / panel CSI reporting).

[0127] In some examples, a CSI report for a single TRP / panel mode may include one or more of the following: a measurement based on a single CSI-RS resource, a single rank indicator (RI), a single CSI-RS resource indicator (CRI), a single quality indicator (e.g., one or more of the channel quality indicator (CQI), L1-RSRP, and L1-SINR), a single set of precoding matrix indicators (PMIs), e.g., broadband w1 and broadband w2, broadband w1 and subband w2s, or one or more of a single layer indicator (LI).

[0128] In some examples, a CSI report for a multi-TRP / panel may include measurements based on a single CSI-RS resource, multiple RIs, multiple CRIs, multiple quality indicators (e.g., one or more of Channel Quality Indicator (CQI), L1-RSRP, and L1-SINR), multiple sets of PMIs (e.g., broadband w1 and broadband w2, broadband w1 and subband w2s), or one or more of multiple LIs.

[0129] In some solutions, the WTRU may determine the CSI reporting type based on one or more configurations or parameters.

[0130] A WTRU may determine the CSI reporting type based on configuration information received from a network node (e.g., a TRP, base station, node B, or another device). For example, a WTRU may receive configuration information indicating the CSI type (e.g., in a CSI reporting configuration). A WTRU may receive information indicating the CSI type in a CSI-RS resource / resource set configuration. A WTRU may receive configuration information for multiple associated CSI-RS resources / resource sets indicating the CSI type. If a WTRU receives a CSI-RS that does not have associated CSI-RS resources, the WTRU may determine a first CSI reporting type (e.g., whether to perform a CSI report to a single TRP / panel). If a WTRU receives a CSI-RS that has one or more associated CSI-RS resources, the WTRU may determine a second CSI reporting type (e.g., to perform a CSI report to multiple TRPs / panels).

[0131] In some cases, a WTRU may receive configuration information indicating the CSI type by receiving multiple associated CSI reporting configurations. For example, if a WTRU receives a CSI reporting configuration without associated CSI reporting configurations, the WTRU may determine a first CSI reporting type (e.g., a CSI report for a single TRP / panel). If a WTRU receives a CSI reporting configuration with one or more associated CSI reporting configurations, the WTRU may determine a second CSI reporting type (e.g., a CSI report for multiple TRPs / panels).

[0132] A WTRU may determine the CSI report type based on the measured and determined quality. For example, a WTRU may receive multiple CSI-RS configurations (e.g., representing CSI-RS resources or resource sets). Based on the multiple CSI-RS configurations, a WTRU may measure a first CSI-RS. If the measured (and determined) quality of the first CSI-RS is above a threshold, the WTRU may determine a first CSI report type (e.g., a CSI report for a single TRP / panel). If the WTRU measures (and determines) the quality of the first CSI-RS configuration to be below (or equal to) a threshold, the WTRU may determine a second CSI report type and measure and determine joint quality based on multiple CSI-RS configurations. The first CSI-RS configuration may represent a CSI-RS resource / resource set for CSI reporting and additional CSI-RS resource / resource set configurations for CSI report type determination.

[0133] In some examples, the WTRU may receive multiple CSI-RS configurations (e.g., resources or resource sets). Based on the multiple CSI-RS configurations, the WTRU may measure a first CSI-RS and a second CSI-RS. If the difference between the first quality of the first CSI-RS and the second quality of the second CSI-RS is higher than a threshold, the WTRU may determine a first CSI report type (e.g., a CSI report for a single TRP / panel). If this difference is lower than (or equal to) the threshold, the WTRU may determine a second CSI report type and measure and determine joint quality based on the multiple CSI-RS configurations.

[0134] For example, a WTRU may receive multiple CSI-RS configurations (e.g., representing resources or resource sets). Based on the multiple CSI-RS configurations, the WTRU may measure multiple CSI-RS. If the measured (and determined) quality (e.g., mean) of the multiple CSI-RS is above a threshold, the WTRU may determine a first CSI reporting type (e.g., a CSI report for a single TRP / panel). If the WTRU measures (and determines) quality below (or equal to) the threshold, the WTRU may determine a second CSI reporting type and measure and determine joint quality based on the multiple CSI-RS.

[0135] Quality metrics may include rank, CQI, SINR, RSRP, RSRQ, path loss, location information, environment type (e.g., indoor or outdoor), amount of interference (e.g., interference quality indicator, IQI), P-MPR, or one or more other metrics).

[0136] If a WTRU supports multiple types of quality for decision-making, the WTRU may receive one of several types from a network node (e.g., TRP, base station, node B, or another device) via, for example, a per-WTRU RRC configuration, CSI reporting configuration, CSI-RS configuration, or another logical equivalent.

[0137] One or more thresholds may be used in a determination based on one or more of the following: predefined values, indicated values ​​(provided, for example, via RRC, MAC CE, DCI, or any other logical equivalent), or values ​​determined by the WTRU (for example, based on the implementation or measurement of the WTRU). The term CSI reporting configuration may be used interchangeably with the term CSI-RS configuration, but may be consistent with the embodiments described.

[0138] Rules for determining duplicate PDCCHs in multi-TRP systems are described herein. Repeating PDCCHs through multi-TRP transmission is one technique that may be used to enhance the reliability of PDCCHs.

[0139] Figure 5 illustrates an example of the basic operation for PDCCH reliability enhancement via repetition. For PDCCH reliability enhanced by repetition, coding and / or rate matching may be based on one repetition, and the same coded bits may be repeated for another repetition. The number of linked PDCCH candidates may be, for example, two, and each repetition may have the same number of CCEs and coded bits and correspond to the same DCI payload. For PDCCH repetitions, several (e.g., two) linked PDCCH candidates may be received in two different CORESETs configured in two different search spaces. As shown in Figure 5, two PDCCH candidates, namely PDCCH1(1) and PDCCH1(2), may be copies of each other and may be transmitted from two different TRPs to enhance reliability. Two search space sets 510 and 520 associated with corresponding CORESETs may be linked to each other, and the link between the two may be established in the WTRU by message transmission received from a network node (for example, the link between PDCCH candidates may be indicated by an RRC message or another logical equivalent). The two SS sets 510 and 520 may have the same aggregation level (AL) and the same candidate index, and may have the same number of candidates for each AL.

[0140] Furthermore, the two linked SS sets 510 and 520 may be configured using the same SS set type (USS / CSS), the same DCI format for monitoring, the same period and offset (for example, as indicated in the message transmission from the network node containing the monitoringSlotPeriodicityAndOffset element), and the same duration. The two SS sets 510 and 520 may have the same number of monitoring opportunities within a slot, and it can be assumed that the nth monitoring opportunity of one SS set is linked to the nth monitoring opportunity of the other SS set.

[0141] In some embodiments, when two SS sets are linked for the repetition of a PDCCH, they do not necessarily have to include individual PDCCH candidates. Different SS sets may be configured by the network (e.g., via downlink transmissions, RRC messages, MAC CEs, or other logical equivalents) for the configuration of individual PDCCH candidates, and one of the configured CORESETs in the SS for linked PDCCHs may be shared by the search space of individual PDCCHs, i.e., unlinked PDCCHs.

[0142] Figures 6A and 6B illustrate another exemplary operation for PDCCH enhancement through two different cases in which PDCCH candidates are linked. As shown in both case (a) and case (b) illustrated by Figures 6A and 6B respectively, PDCCH1, one of the linked PDCCH candidates, uses the same set of CCEs as PDCCH2, an individual (unlinked) PDCCH candidate, and both are associated with the same DCI size, scrambling, and CORESET. From a decoding perspective, different results may be expected depending on the processing and blind decoding (BD) capabilities of the WTRU receiver.

[0143] As shown in Figures 6A and 6B, r1 and r2 may be signals extracted from the corresponding CORESET in the first search space SS#1 (indicated by element 610) and the second search space SS#2 (indicated by element 620). In the case of a WTRU with three BD capabilities, the WTRU can generally attempt to perform blind decoding three times, as follows: In the first case, the WTRU can attempt to decode r1. In the second case, the WTRU can attempt to decode r2, and in the third case, the WTRU can attempt to decode the soft coupling of signals r1 and r2.

[0144] Assuming the above sequence for decoding trials and given relative powers, there may be no clear difference in decoding performance between case (a) and (b) shown in Figures 6A and 6B. However, knowing which repetitions of PDCCH1 overlap with individual PDCCHs may provide better performance and opportunities for power saving.

[0145] In the case of a WTRU with two BD capabilities, the WTRU can generally attempt to perform blind decoding twice, as follows: In the first case, the WTRU can attempt to decode r1, and in the second case, the WTRU can attempt to decode r2. Assuming the above order for decoding attempts and a given relative power, there may be no difference in decoding performance between case (a) shown in Figure 6A and case (b) shown in Figure 6B.

[0146] In the case of a WTRU with two BDs and soft coupling capabilities, the WTRU can generally attempt to perform blind decoding twice, as follows: In the first case, the WTRU can attempt to decode r1, and in the second case, the WTRU can attempt to perform blind decoding of the soft coupling of signals r1 and r2. Unlike the previous two cases, there may be a difference in decoding performance between case (a) in Figure 6A and case (b) in Figure 6B depending on the order of trials described above. For example, if the above order of trials is applied to case (b), the performance may be worse than in case (a).

[0147] In some embodiments, the WTRU may prioritize decoding of extracted candidates, i.e., r1, r2, and / or soft-coupled signals r1 and r2, based on several pieces of information, such as relative signal levels or whether the PDCCHs overlap. In some solutions, the WTRU may determine, based on one or more rules as described in further detail herein, whether the extracted signals, i.e., r1 or r2, carry the overlapping PDCCH.

[0148] For example, the WTRU may determine whether the location of a PDCCH candidate contains only one of the linked PDCCH candidates, based on the search space index. In some solutions, the WTRU may assume that individual PDCCHs can only be received in the search space where they have the highest (or lowest) ID.

[0149] The WTRU may determine, based on a time criterion, whether the location of a PDCCH candidate contains only one of the linked PDCCH candidates. In some solutions, the WTRU may assume that individual PDCCH transmissions can only be received in a search space that starts earlier (or later) than another search space. Alternatively or additionally, the WTRU may assume that individual PDCCH transmissions can only be received in a CORESET that starts earlier (or later) than another CORESET.

[0150] The WTRU may determine, based on the CORESET index, whether the location of a PDCCH candidate contains only one of the linked PDCCH candidates. In some solutions, the WTRU may assume that individual PDCCHs can only be received in the CORESET with the highest (or lowest) ID.

[0151] The WTRU may determine whether the location of a PDCCH candidate contains only one of the linked PDCCH candidates, based on the configured TCI state of the search space or the associated CORESET pool index (i.e., the associated CORESETpoolIndex element indicated in the message from the network node). In some solutions, the WTRU may assume that individual PDCCHs can only be received in a CORESET or search space associated with CORESETpoolIndex=0 (or 1). Alternatively or additionally, the WTRU may assume that individual PDCCH transmissions can only be received in a CORESET or search space associated with a TCI that is quasi-co-located (QCL-ed) with a particular RS, e.g., a Synchronization Signal Block (SSB).

[0152] If the WTRU does not have the capability for simultaneous multibeam reception, the WTRU may assume that overlapping PDCCHs, i.e., PDCCH1(2) and the individual PDCCH2 in case (a) of Figure 6A, are both transmitted from the same TRP, for example, sharing the same TCI. Therefore, the same QCL type D may be used for receiving both PDCCH transmissions. Alternatively or additionally, in the same example, if the WTRU does not have the capability for simultaneous multibeam reception, the WTRU may use at least one of the following for determining the QCL type D parameter: For example, the WTRU may use the QCL type D parameter of a stronger concatenation, e.g., the PDCCH corresponding to the highest RSRP, i.e., PDCCH1(2) or the individual PDCCH2, the QCL type D parameter of a concatenated PDCCH, i.e., PDCCH1(2), the QCL type D parameter of the individual PDCCH, or the QCL type D of a PDCCH candidate with a higher search space priority.

[0153] In some solutions, a WTRU with simultaneous multi-beam receiving capability may also consider at least one of the above conditions.

[0154] While features and elements are described above in specific combinations, those skilled in the art will understand that each feature or element can be used alone or in any combination with other features and elements. In addition, the methods described herein can be implemented in computer programs, software, or firmware embedded in computer-readable media for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted via 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 disks (DVDs). A processor associated with software can be used to implement radio frequency transceivers for use in WTRUs, WTRU terminals, base stations, RNCs, or any host computer.

Claims

1. A method carried out by a wireless transmit / receive unit (WTRU), wherein the method is Receiving one or more first channel status information reference signals (CSI-RS) from each of the first transmit / receive point (TRP) and the second TRP, Based on the one or more first CSI-RSs, the first CSI amounts associated with each of the first TRP and the second TRP are determined. Based on the respective CSI amounts of the first, one of the first TRP or the second TRP is selected as the primary TRP, and the remaining one of the first TRP or the second TRP is selected as the secondary TRP. To report information indicating at least the respective first CSI amounts associated with the primary TRP, Receiving one or more second CSI-RS from the primary TRP, wherein the one or more second CSI-RS received from the primary TRP are precoded by the primary TRP based on at least each of the first CSI quantities associated with the primary TRP. Based on the one or more second CSI-RS received from the primary TRP, a second CSI quantity and a first precoding matrix indicator (PMI) for the primary TRP are determined. Determining channel coding parameters associated with the one or more precoded second CSI-RSs received from the primary TRP and associated with the first PMI for the primary TRP, Receiving one or more third CSI-RS signals from the secondary TRP, Based on the one or more third CSI-RS received from the secondary TRP, a second CSI amount associated with the secondary TRP is determined, Determining a second PMI for the secondary TRP that reduces interlayer interference between the primary TRP and the secondary TRP, based on the channel coding parameters associated with the first PMI for the primary TRP and the second CSI amount associated with the secondary TRP, and associated with one or more precoded second CSI-RSs, To report information indicating the second PMI for the secondary TRP, Methods that include...

2. The method according to claim 1, comprising calculating a null space associated with the one or more precoded second CSI-RSs received from the primary TRP, wherein the second PMI for the secondary TRP is determined based on the null space associated with the one or more precoded second CSI-RSs received from the primary TRP.

3. The method according to claim 1, further comprising receiving configuration information that provides an indication of resources for receiving at least some of the one or more first CSI-RS, the one or more second CSI-RS, or the one or more third CSI-RS.

4. The method according to claim 1, wherein the selection of at least the first TRP as the primary TRP is further based on a comparison between at least one of the first CSI amounts and a threshold.

5. The method according to claim 1, wherein a transmission including at least each of the first CSI amounts associated with the primary TRP is transmitted to the primary TRP.

6. The method according to claim 1, wherein a transmission including at least each of the first CSI amounts associated with the primary TRP includes information indicating the selection of the first TRP as the primary TRP.

7. The method according to claim 1, further comprising determining a plurality of PMIs for the primary TRP and a plurality of PMIs for the secondary TRP.

8. The method according to claim 7, further comprising determining from each of the plurality of PMIs a certain number of best PMIs for the primary TRP and the same number of best PMIs for the secondary TRP.

9. The method according to claim 7, further comprising associating at least one of the plurality of PMIs for the primary TRP with at least one of the plurality of PMIs for the secondary TRP, and transmitting a report containing information indicating the association between at least one of the plurality of PMIs for the primary TRP and at least one of the plurality of PMIs for the secondary TRP.

10. A wireless transmitter / receiver unit (WTRU), Processor and Equipped with a transceiver, The transceiver is configured to receive one or more first channel status information reference signals (CSI-RS) from each of the first transmit / receive point (TRP) and the second TRP, The processor is configured to determine a first CSI amount associated with each of the first TRP and the second TRP based on one or more first CSI-RSs, The processor is further configured to select one of the first TRP or the second TRP as the primary TRP based on the respective first CSI amounts, and to select the remaining one of the first TRP or the second TRP as the secondary TRP. The processor and the transceiver are further configured to report information indicating at least the respective first CSI quantities associated with the primary TRP, The transceiver is further configured to receive one or more second CSI-RS from the primary TRP, and the one or more second CSI-RS received from the primary TRP are precoded by the primary TRP based on at least the respective first CSI amounts associated with the primary TRP. The processor is further configured to determine a second CSI quantity and a first precoding matrix indicator (PMI) for the primary TRP based on one or more second CSI-RS received from the primary TRP. The processor is further configured to associate with the one or more precoded second CSI-RSs received from the primary TRP and to determine channel coding parameters associated with the first PMI for the primary TRP. The transceiver is further configured to receive one or more third CSI-RS signals from the secondary TRP. The processor is further configured to determine a second CSI amount associated with the secondary TRP based on one or more third CSI-RSs received from the secondary TRP, The processor is further configured to determine a second PMI for the secondary TRP that reduces interlayer interference between the primary TRP and the secondary TRP, based on the channel coding parameters associated with the first PMI for the primary TRP and the second CSI amount associated with the secondary TRP, associated with one or more precoded second CSI-RSs. The processor and the transceiver are further configured to report information indicating the second PMI for the secondary TRP. WTRU.

11. The WTRU according to claim 10, wherein the processor is further configured to compute a null space associated with the one or more precoded second CSI-RSs received from the primary TRP, and the second PMI for the secondary TRP is determined based on the null space associated with the one or more second CSI-RSs received from the primary TRP.

12. The WTRU according to claim 10, wherein the transceiver is configured to receive configuration information that provides an indication of resources for receiving at least some of the one or more first CSI-RSs, the one or more second CSI-RSs, or the one or more third CSI-RSs.

13. The WTRU according to claim 10, wherein the processor is further configured to select at least one of the first CSI amounts as the primary TRP based on a comparison between the two thresholds.

14. The WTRU according to claim 10, wherein the transceiver is further configured to transmit to the primary TRP a transmission including each of the first CSI amounts associated with the primary TRP.

15. The WTRU according to claim 10, wherein a transmission including each of the first CSI amounts associated with the primary TRP includes information indicating the selection of the first TRP as the primary TRP.

16. The WTRU according to claim 10, wherein the processor is further configured to determine a plurality of PMIs for the primary TRP and a plurality of PMIs for the secondary TRP.

17. The WTRU according to claim 16, wherein the processor is further configured to determine from each of a plurality of PMIs a certain number of best PMIs for the primary TRP and the same number of best PMIs for the secondary TRP.

18. The WTRU according to claim 16, wherein the processor is further configured to associate at least one of the plurality of PMIs for the primary TRP with at least one of the plurality of PMIs for the secondary TRP, and the processor and the transceiver are further configured to transmit a report containing information indicating the association between at least one of the plurality of PMIs for the primary TRP and at least one of the plurality of PMIs for the secondary TRP.

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