Coherent joint transmit csi reporting associated with fdd

Abstract

Systems, methods, and tools for joint transmit (JT) channel state information (CSI) reporting are described herein. The joint transmit CSI may be coherent JT CSI or incoherent JT CSI. For example, if CSI for multiple transmission / reception points (TRPs) is reported, feedback overhead may be reduced. A precoding matrix indicator (PMI) and / or co-phase information for a TRP in a JT (e.g., a coherent JT or a non-coherent JT) may be reported. A wireless transmit / receive unit (WTRU) may be configured to employ operations to reduce feedback overhead and / or report PMI and / or co-phase information for a TRP in a JT.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 326,416, filed on April 1, 2022, and U.S. Provisional Application No. 63 / 395,390, filed on August 5, 2022, the contents of which are incorporated herein by reference in their entirety. Background Art

[0003] Mobile communications using wireless communications continue to evolve. The fifth generation of mobile communications radio access technology (RAT) may be referred to as 5G New Radio (NR). Previous generation (legacy) mobile communications RAT may be, for example, fourth generation (4G) Long Term Evolution (LTE). Summary of the invention

[0004] Systems, methods, and tools for joint transmit (JT) channel state information (CSI) reporting are described herein. The joint transmit CSI may be coherent JT CSI or non-coherent JT CSI. For example, if CSI for multiple transmit / receive points (TRPs) is reported, feedback overhead may be reduced. Precoding matrix indicators (PMI) and / or co-phase information may be reported for TRPs in a JT (e.g., coherent JT or non-coherent JT). A wireless transmit / receive unit (WTRU) may employ operations to reduce feedback overhead and / or report PMI and / or co-phase information for TRPs in a JT.

[0005] The WTRU may receive CSI reporting configuration information indicating a set of codebook indices (CIs) and a plurality of TRPs. The CSI reporting configuration information may indicate the number of columns in a matrix (e.g., a spatial domain matrix, a frequency domain matrix, etc.) associated with (e.g., each) TRP in the plurality of TRPs. The WTRU may determine PMI information for a subset of TRPs from the plurality of TRPs (e.g., where the subset of TRPs may be determined by the WTRU and / or indicated in the CSI reporting configuration information). The WTRU may determine the PMI information based on receiving and / or measuring an RS (e.g., a CSI-RS). The PMI information may include a channel quality indicator (CQI) value. The WTRU may determine a subset of TRPs (e.g., from a plurality of subsets of TRPs or the plurality of TRPs) based on the PMI information (e.g., a subset of TRPs with the highest CQI value may be selected). The WTRU may determine, for example, based on the configuration information (e.g., CI) that at least two TRPs in the determined subset of TRPs are shared based on the basis (e.g., in the spatial domain and / or frequency domain). The WTRU may transmit a CSI report associated with the selected TRP subset. The CSI report may indicate the determined TRP subset and the determined PMI information associated with the determined TRP subset. The CSI report may include a shared CI associated with the at least two TRPs that are shared on a base basis, for example, to reduce signaling overhead. The CSI report may include a non-shared CI associated with a TRP in the TRP subset that is not shared on a base basis.

[0006] The compression operation may be enhanced, for example, to reduce overhead information. For example, the WTRU may report a basis set (e.g., a spatial basis set, a frequency basis set, a time basis set, etc.) for a coherent JT TRP. The WTRU may report a compressed basis set. The WTRU may be configured to report a compressed basis set shared by multiple coherent JT TRPs. The WTRU may report a coefficient set. The WTRU may report a coefficient set per TRP.

[0007] The WTRU may generate a basis matrix, for example, for use in PMI calculations. The WTRU may generate a basis matrix using a basis set from a TRP (eg, a different associated TRP).

[0008] The WTRU may report CSI. The CSI may include CSI components. The WTRU may report different CSI component granularities, such as, for example, the number of bases, the number of coefficients, etc. The WTRU may report different CSI component granularities, for example, for coherent JT TRPs (eg, different coherent JTTRPs).

[0009] The WTRU may report CSI (e.g., PMI) for a TRP. The WTRU may receive an indication indicating a set of TRP pairs. The WTRU may receive configuration information indicating a set of resources associated with the CSI report. The WTRU may determine the CSI for each TRP pair in the set of TRP pairs. The WTRU may determine that the set of resources is below a threshold associated with the set of TRP pairs (e.g., the amount of resources in the set of resources is insufficient to accommodate all TRP pairs). The WTRU may determine a subset of TRP pairs. The subset of TRP pairs may be determined from the set of TRP pairs. The WTRU may perform measurements (e.g., RSRP) on the TRPs in the set of TRP pairs. For example, if the measurements performed on the TRPs are above a threshold, the WTRU may select a TRP for the subset of TRPs. The WTRU may transmit a set of CSI. The WTRU may select CSI report content. For example, the WTRU may select CSI report content based on RS groups and / or port groups. The CSI set may include CSI associated with the TRP pairs in the subset of TRP pairs. For example, the WTRU may report CSI for a subset of TRPs for which it has sufficient resources. In an example, the WTRU may report CSI for a secondary TRP, for example, which is dependent on the CSI (e.g., PMI) of the primary TRP.

[0010] The WTRU may switch between reporting settings. For example, the WTRU may switch between reporting the aggregated PMI for aggregated channels (e.g., from a coherent JT TRP) and reporting per-TRP PMI and co-phasing factor.

[0011] The WTRU may determine, for example, a transmission configuration indicator (TCI) for a CSI resource. The TCI may indicate an association between a physical channel (e.g., used for a transmission) and a transmission (e.g., a reference signal transmission, such as a demodulation reference signal transmission) transmitted using the physical channel. The WTRU may determine a TCI per port. The WTRU may determine a TCI per port group for a CSI resource having multiple port groups. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1A is a system diagram illustrating an example communication system in which one or more disclosed embodiments may be implemented.

[0013] Figure 1B is an example of a method that can be used according to an embodiment of the present invention. Figure 1A A system diagram of an example wireless transmit / receive unit (WTRU) for use within an example communication system.

[0014] Figure 1C is an example of a method that can be used according to an embodiment of the present invention. Figure 1A System diagram of an example Radio Access Network (RAN) and an example Core Network (CN) used within an illustrated communication system.

[0015] Figure 1D is an example of a method that can be used according to an embodiment of the present invention. Figure 1A System diagram of yet another example RAN and yet another example CN for use within the illustrated communication system.

[0016] Figure 2 An example of joint transmission from multiple TRPs to a WTRU is illustrated.

[0017] Figure 3 An example of CSI reporting for multi-TRP CJT is illustrated.

[0018] Figure 4 An example type of association between TCI status and PG is illustrated. DETAILED DESCRIPTION

[0019] Figure 1A 1 is a diagram illustrating an example communication system 100 in which one or more disclosed embodiments may be implemented. The communication system 100 may be a multiple access system that provides content such as voice, data, video, messaging, broadcast, etc. to multiple wireless users. The communication system 100 may enable multiple wireless users to access such content through sharing of system resources (including wireless bandwidth). For example, the communication system 100 may employ one or more channel access methods such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single carrier FDMA (SC-FDMA), zero tail unique word DFT spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, filter bank multi-carrier (FBMC), etc.

[0020] like Figure 1AAs shown, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, RAN 104 / 113, CN 106 / 115, public switched telephone network (PSTN) 108, Internet 110 and other networks 112, but it should be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 102d (any of which may be referred to as a “station” and / or “STA”) may be configured to send and / or receive wireless signals and may include user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a cellular phone, a personal digital assistant (PDA), a smart phone, a laptop, a netbook, a personal computer, a wireless sensor, a hotspot or Mi-Fi device, an Internet of Things (IoT) device, a watch or other wearable device, a head-mounted display (HMD), a vehicle, a drone, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in an industrial and / or automated process chain environment), a consumer electronic device, a device operating on a commercial and / or industrial wireless network, etc. Any of the WTRUs 102a, 102b, 102c, and 102d may be interchangeably referred to as a UE.

[0021] The communication system 100 may also include a base station 114a and / or a base station 114b. Each of the base stations 114a, 114b may be any type of device that is configured to interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks, such as the CN 106 / 115, the Internet 110, and / or other networks 112. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a Node B, an eNode B, a Home Node B, a Home eNode B, a gNB, an NR Node B, a site controller, an access point (AP), a wireless router, and the like. Although the base stations 114a, 114b are each depicted as a single element, it should be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0022] The base station 114a may be part of the RAN 104 / 113, which may also include other base stations and / or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), a relay node, etc. The base station 114a and / or the base station 114b may be configured to send and / or receive wireless signals on one or more carrier frequencies (which may be referred to as cells (not shown)). These frequencies may be in a licensed spectrum, an unlicensed spectrum, or a combination of licensed and unlicensed spectrums. A cell may provide coverage of wireless services to a specific geographic area, which may be relatively fixed or may change over time. The cell may be further divided into cell sectors. For example, a cell associated with the base station 114a may be divided into three sectors. Therefore, in one embodiment, the base station 114a may include three transceivers, i.e., one transceiver for each sector of the cell. In an embodiment, the base station 114a may employ multiple-input multiple-output (MIMO) technology and may utilize multiple transceivers for each sector of the cell. For example, beamforming may be used to send and / or receive signals in a desired spatial direction.

[0023] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over an air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

[0024] More specifically, as noted above, the communication system 100 may be a multiple access system and may employ one or more channel access schemes such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, the base station 114a in the RAN 104 / 113 and the WTRUs 102a, 102b, 102c may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may use Wideband CDMA (WCDMA) to establish the air interface 115 / 116 / 117. WCDMA may include communication protocols such as High Speed ​​Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA may include High Speed ​​Downlink (DL) Packet Access (HSDPA) and / or High Speed ​​UL Packet Access (HSUPA).

[0025] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface 116 using Long Term Evolution (LTE) and / or Advanced LTE (LTE-A) and / or Advanced LTE Pro (LTE-A Pro).

[0026] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR radio access, which may establish the air interface 116 using New Radio (NR).

[0027] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may together implement LTE radio access and NR radio access, for example using the dual connectivity (DC) principle. Thus, the air interface used by the WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions transmitted to / from multiple types of base stations (e.g., eNBs and gNBs).

[0028] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE 802.11 (i.e., Wireless Fidelity (WiFi)), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile Communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), etc.

[0029] Figure 1AThe base station 114b in the may be, for example, a wireless router, a Home NodeB, a Home eNodeB, or an access point, and may utilize any suitable RAT to facilitate wireless connectivity in local areas such as commercial venues, homes, vehicles, campuses, industrial facilities, sky corridors (e.g., for use by drones), roads, and the like. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement radio technologies such as IEEE 802.11 to establish a wireless local area network (WLAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement radio technologies such as IEEE 802.15 to establish a wireless personal area network (WPAN). In another embodiment, the base station 114b and the WTRUs 102c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish a picocell or a femtocell. As Figure 1A As shown, base station 114b may have a direct connection to Internet 110. Therefore, base station 114b may not need to access Internet 110 via CN 106 / 115.

[0030] The RAN 104 / 113 may be in communication with the CN 106 / 115, which may be any type of network configured to provide voice, data, applications and / or Voice over Internet Protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have different quality of service (QoS) requirements, such as different throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. The CN 106 / 115 may provide call control, billing services, mobile location-based services, prepaid calling, Internet connectivity, video distribution, etc., and / or perform high-level security functions, such as user authentication. Although not described in detail in the text and video, the CN 106 / 115 may be configured to provide voice, data, applications and / or Voice over Internet Protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have different quality of service (QoS) requirements, such as different throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. The CN 106 / 115 may provide call control, billing services, mobile location-based services, prepaid calling, Internet connectivity, video distribution, etc., and / or perform high-level security functions, such as user authentication. Figure 1A Although not shown in the figure, it will be appreciated that the RAN 104 / 113 and / or the CN 106 / 115 may be in direct or indirect communication with other RANs that employ the same RAT as the RAN 104 / 113 or a different RAT. For example, in addition to being connected to the RAN 104 / 113, which may utilize NR radio technology, the CN 106 / 115 may also be in communication with another RAN (not shown) that employs GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0031] The CN 106 / 115 may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and / or other networks 112. The PSTN 108 may include a circuit-switched telephone network that provides plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols, such as the Transmission Control Protocol (TCP), the User Datagram Protocol (UDP), and / or the Internet Protocol (IP) in the TCP / IP Internet protocol suite. The networks 112 may include wired communication networks and / or wireless communication networks owned and / or operated by other service providers. For example, the networks 112 may include another CN connected to one or more RANs, which may employ the same RAT as the RAN 104 / 113 or a different RAT.

[0032] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communication system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks via different wireless links). Figure 1A The illustrated WTRU 102c may be configured to communicate with the base station 114a, which may employ a cellular-based radio technology, and with the base station 114b, which may employ an IEEE 802 radio technology.

[0033] Figure 1B is a system diagram illustrating an example WTRU 102. Figure 1B As shown, the WTRU 102 may include, among other things, a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and / or other peripherals 138. It will be appreciated that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment.

[0034] The processor 118 may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), a state machine, etc. The processor 118 may perform signal decoding, data processing, power control, input / output processing, and / or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit / receive element 122. Although Figure 1B The processor 118 and the transceiver 120 are depicted as separate components, but it is understood that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0035] The send / receive element 122 may be configured to send a signal to a base station (e.g., base station 114a) or receive a signal from the base station via an air interface 116. For example, in one embodiment, the send / receive element 122 may be an antenna configured to send and / or receive an RF signal. In an embodiment, the send / receive element 122 may be a transmitter / detector configured to send and / or receive, for example, an IR, UV or visible light signal. In another embodiment, the send / receive element 122 may be configured to send and / or receive both an RF signal and an optical signal. It should be understood that the send / receive element 122 may be configured to send and / or receive any combination of wireless signals.

[0036] Although the transmit / receive element 122 Figure 1B 1 as a single element, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116.

[0037] The transceiver 120 may be configured to modulate signals to be transmitted by the transmit / receive element 122 and to demodulate signals received by the transmit / receive element 122. As noted above, the WTRU 102 may have multi-mode capabilities. For example, the transceiver 120 may include multiple transceivers for enabling the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11.

[0038] The processor 118 of the WTRU 102 may be coupled to and may receive user input data from a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light emitting diode (OLED) display unit). The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. In addition, the processor 118 may access information from and store data in any type of suitable memory, such as a non-removable memory 130 and / or a removable memory 132. The non-removable memory 130 may include a random access memory (RAM), a read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, and the like. In other embodiments, the processor 118 may access information from and store data in a memory that is not physically located on the WTRU 102, such as on a server or a home computer (not shown).

[0039] The processor 118 may receive power from the power source 134, and may be configured to distribute and / or control power to other components in the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power source 134 may include one or more dry cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel-metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0040] The processor 118 may also be coupled to the GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to or in lieu of the information from the GPS chipset 136, the WTRU 102 may receive location information from a base station (e.g., base stations 114a, 114b) over the air interface 116 and / or determine its location based on the timing of signals received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information by any suitable location-determination method while remaining consistent with an embodiment.

[0041] The processor 118 may also be coupled to other peripherals 138, which may include one or more software modules and / or hardware modules that provide additional features, functionality, and / or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an electronic compass, a satellite transceiver, a digital camera (for photos and / or video), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands-free headset, module, a frequency modulation (FM) radio unit, a digital music player, a media player, a video game player module, an Internet browser, a virtual reality and / or augmented reality (VR / AR) device, an activity tracker, etc. Peripheral device 138 may include one or more sensors, which may be one or more of the following: a gyroscope, an accelerometer, a Hall effect sensor, a magnetometer, an orientation sensor, a proximity sensor, a temperature sensor, a time sensor; a geolocation sensor; an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, and / or a humidity sensor.

[0042] The WTRU 102 may include a full-duplex radio for which transmission and reception of some or all signals (e.g., associated with specific subframes for both UL (e.g., for transmission) and downlink (e.g., for reception)) may be concurrent and / or simultaneous. The full-duplex radio may include an interference management unit for reducing and / or substantially eliminating self-interference via signal processing performed via hardware (e.g., a choke) or via a processor (e.g., a separate processor (not shown) or via the processor 118). In an embodiment, the WRTU 102 may include a half-duplex radio for which transmission and reception of some or all signals (e.g., associated with specific subframes for both UL (e.g., for transmission) or downlink (e.g., for reception)) may be concurrent and / or simultaneous.

[0043] Figure 1C 1 is a system diagram illustrating the RAN 104 and the CN 106 in accordance with an embodiment. As noted above, the RAN 104 may employ an E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0044] The RAN 104 may include evolved Node-Bs 160a, 160b, 160c, though it will be appreciated that the RAN 104 may include any number of evolved Node-Bs while remaining consistent with an embodiment. The evolved Node-Bs 160a, 160b, 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the evolved Node-Bs 160a, 160b, 160c may implement MIMO technology. Thus, the evolved Node-B 160a, for example, may use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a.

[0045] Each of the evolved Node Bs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and / or DL, etc. Figure 1C As shown, the eNode-Bs 160a, 160b, 160c may communicate with one another via an X2 interface.

[0046] Figure 1C The illustrated CN 106 may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. While each of the foregoing elements is depicted as being part of the CN 106, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0047] The MME 162 may be connected to each of the evolved Node-Bs 162a, 162b, 162c in the RAN 104 via an S1 interface and may serve as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer activation / deactivation, selecting a particular serving gateway during an initial attach of the WTRUs 102a, 102b, 102c, etc. The MME 162 may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as GSM and / or WCDMA.

[0048] The SGW 164 may be connected to each of the evolved Node-Bs 160a, 160b, 160c in the RAN 104 via an S1 interface. The SGW 164 may generally route and forward user data packets to / from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions, such as anchoring the user plane during inter-evolved Node-B handovers, triggering paging when DL data is available for the WTRUs 102a, 102b, 102c, managing and storing the context of the WTRUs 102a, 102b, 102c, and the like.

[0049] The SGW 164 may be connected to the PGW 166, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0050] The CN 106 may facilitate communications with other networks. For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional land-line communications devices. For example, the CN 106 may include, or may be in communication with, an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired networks and / or wireless networks owned and / or operated by other service providers.

[0051] Although the WTRU Figures 1A to 1D Although described as wireless terminals, it is contemplated that in certain representative embodiments, such terminals may (eg, temporarily or permanently) use a wired communication interface with a communication network.

[0052] In a representative embodiment, the other network 112 may be a WLAN.

[0053] A WLAN in infrastructure basic service set (BSS) mode may have an access point (AP) for a BSS and one or more stations (STA) associated with the AP. The AP may have access or an interface to a distribution system (DS) or another type of wired / wireless network that carries traffic to and / or carries traffic away from the BSS. Traffic originating from outside the BSS and leading to the STA may be reached by the AP and may be delivered to the STA. Traffic originating from the STA and leading to a destination outside the BSS may be transmitted to the AP to be delivered to the corresponding destination. Traffic between STAs within the BSS may be transmitted by the AP, for example, wherein the source STA may transmit traffic to the AP, and the AP may deliver traffic to the target STA. Traffic between STAs within the BSS may be considered and / or referred to as point-to-point traffic. Point-to-point traffic may be transmitted between the source STA and the target STA (e.g., directly between them) using a direct link setup (DLS). In certain representative embodiments, the DLS may use 802.11e DLS or 802.11z tunnel DLS (TDLS). A WLAN using an independent BSS (IBSS) mode may not have an AP, and STAs within or using the IBSS (eg, all STAs in the STA) may communicate directly with each other. The IBSS communication mode may sometimes be referred to herein as an "ad-hoc" communication mode.

[0054] When using the 802.11ac infrastructure operating mode or a similar operating mode, the AP may send beacons on a fixed channel (such as a primary channel). The primary channel may be a fixed width (e.g., a 20 MHz wide bandwidth) or a width dynamically set via signaling. The primary channel may be an operating channel of the BSS and may be used by the STA to establish a connection with the AP. In certain representative embodiments, carrier sense multiple access / collision avoidance (CSMA / CA) may be implemented, for example, in an 802.11 system. For CSMA / CA, a STA (e.g., each STA) (including the AP) may listen to the primary channel. If the primary channel is listened / detected and / or determined to be busy by a particular STA, the particular STA may back off. One STA (e.g., only one station) may transmit at any given time in a given BSS.

[0055] High throughput (HT) STAs may communicate using a 40 MHz wide channel, for example, via a combination of a primary 20 MHz channel and adjacent or non-adjacent 20 MHz channels to form a 40 MHz wide channel.

[0056] Very high throughput (VHT) STA can support 20MHz, 40MHz, 80MHz and / or 160MHz wide channels. 40MHz channels and / or 80MHz channels can be formed by combining continuous 20MHz channels. 160MHz channels can be formed by combining 8 continuous 20MHz channels, or by combining two non-continuous 80MHz channels (this can be called 80+80 configuration). For 80+80 configuration, after channel coding, the data can pass through a segment parser that can divide the data into two streams. Each stream can be processed by inverse fast Fourier transform (IFFT) and time domain processing separately. These streams can be mapped to two 80MHz channels, and data can be sent by the transmitter STA. At the receiver of the receiver STA, the above-mentioned operation for the 80+80 configuration can be reversed, and the combined data can be transmitted to the medium access control (MAC).

[0057] 802.11af and 802.11ah support operating modes below 1GHz. Channel operating bandwidths and carriers are reduced in 802.11af and 802.11ah relative to those used in 802.11n and 802.11ac. 802.11af supports 5MHz, 10MHz, and 20MHz bandwidths in the TV White Space (TVWS) spectrum, and 802.11ah supports 1MHz, 2MHz, 4MHz, 8MHz, and 16MHz bandwidths using non-TVWS spectrum. According to a representative embodiment, 802.11ah may support instrument type control / machine type communications, such as MTC devices in macro coverage areas. MTC devices may have certain capabilities, such as limited capabilities, including support for (e.g., only support for) certain bandwidths and / or limited bandwidths. MTC devices may include batteries with battery life above a threshold (e.g., to maintain very long battery life).

[0058] WLAN systems that can support multiple channels and channel bandwidths (such as 802.11n, 802.11ac, 802.11af, and 802.11ah) include channels that can be designated as primary channels. The primary channel may have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and / or limited by a STA (which supports the minimum bandwidth operating mode) from all STAs operating in the BSS. In the example of 802.11ah, for STAs (e.g., MTC-type devices) that support (e.g., only support) a 1MHz mode, the primary channel may be 1MHz wide, even if the AP and other STAs in the BSS support 2MHz, 4MHz, 8MHz, 16MHz, and / or other channel bandwidth operating modes. Carrier sensing and / or network allocation vector (NAV) settings may depend on the state of the primary channel. If the primary channel is busy, for example, because a STA (supporting only a 1MHz operating mode) is sending to the AP, the entire available frequency band may be considered busy even if most of the frequency bands remain idle and may be available.

[0059] In the United States, the available frequency band for 802.11ah is 902MHz to 928MHz. In South Korea, the available frequency band is 917.5MHz to 923.5MHz. In Japan, the available frequency band is 916.5MHz to 927.5MHz. The total bandwidth available for 802.11ah is 6MHz to 26MHz, depending on the country code.

[0060] Figure 1D 1 is a system diagram illustrating the RAN 113 and the CN 115 in accordance with an embodiment. As noted above, the RAN 113 may employ NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 113 may also be in communication with the CN 115.

[0061] The RAN 113 may include gNBs 180a, 180b, 180c, though it will be appreciated that the RAN 113 may include any number of gNBs while remaining consistent with an embodiment. The gNBs 180a, 180b, 180c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the gNBs 180a, 180b, 180c may implement MIMO technology. For example, the gNBs 180a, 180b may utilize beamforming to send signals to and / or receive signals from the gNBs 180a, 180b, 180c. Thus, the gNB 180a may, for example, use multiple antennas to send wireless signals to and / or receive wireless signals from the WTRU 102a. In an embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation technology. For example, gNB 180a may transmit multiple component carriers to WTRU 102a (not shown). A subset of these component carriers may be on unlicensed spectrum, while the remaining component carriers may be on licensed spectrum. In an embodiment, gNBs 180a, 180b, 180c may implement coordinated multi-point (CoMP) technology. For example, WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and / or gNB 180c).

[0062] The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using transmissions associated with parameter sets that may be scalable. For example, OFDM symbol spacing and / or OFDM subcarrier spacing may vary for different transmissions, different cells, and / or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using subframes or Transmission Time Intervals (TTIs) of varying or scalable lengths (e.g., containing varying numbers of OFDM symbols and / or varying absolute time lengths over time).

[0063] The gNBs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in a standalone configuration and / or a non-standalone configuration. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c while not accessing other RANs (e.g., such as the eNodeBs 160a, 160b, 160c). In a standalone configuration, the WTRUs 102a, 102b, 102c may use one or more of the gNBs 180a, 180b, 180c as mobility anchors. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using signals in an unlicensed band. In a non-standalone configuration, the WTRU 102a, 102b, 102c may communicate / connect with the gNB 180a, 180b, 180c while also communicating / connecting with another RAN, such as the evolved Node-B 160a, 160b, 160c. For example, the WTRU 102a, 102b, 102c may implement the DC principle to communicate with one or more gNBs 180a, 180b, 180c and one or more evolved Node-Bs 160a, 160b, 160c substantially simultaneously. In a non-standalone configuration, the evolved Node-B 160a, 160b, 160c may act as a mobility anchor for the WTRU 102a, 102b, 102c, and the gNB 180a, 180b, 180c may provide additional coverage and / or throughput for serving the WTRU 102a, 102b, 102c.

[0064] Each of the gNBs 180a, 180b, 180c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in UL and / or DL, support of network slicing, dual connectivity, interworking between NR and E-UTRA, routing of user plane data towards a user plane function (UPF) 184a, 184b, routing of control plane information towards an access and mobility management function (AMF) 182a, 182b, etc. Figure 1D As shown, gNBs 180a, 180b, and 180c may communicate with each other via an Xn interface.

[0065] Figure 1DThe illustrated CN 115 may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one session management function (SMF) 183a, 183b, and possible data networks (DNs) 185a, 185b. Although each of the foregoing elements is depicted as part of the CN 115, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0066] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via the N2 interface and may act as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRU 102a, 102b, 102c, support of network slicing (e.g., handling of different PDU sessions with different requirements), selecting a specific SMF 183a, 183b, management of registration areas, termination of NAS signaling, mobility management, etc. The AMF 182a, 182b may use network slicing in order to customize CN support for the WTRU 102a, 102b, 102c based on the type of services utilized by the WTRU 102a, 102b, 102c. For example, different network slices may be established for different use cases, such as services relying on ultra-reliable low latency (URLLC) access, services relying on enhanced mobile broadband (eMBB) access, services for machine type communication (MTC) access, etc. The AMF 162 may provide a control plane function for switching between the RAN 113 and other RANs (not shown) that employ other radio technologies, such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies, such as WiFi.

[0067] The SMF 183a, 183b may be connected to the AMF 182a, 182b in the CN 115 via the N11 interface. The SMF 183a, 183b may also be connected to the UPF 184a, 184b in the CN 115 via the N4 interface. The SMF 183a, 183b may select and control the UPF 184a, 184b, and configure traffic routing through the UPF 184a, 184b. The SMF 183a, 183b may perform other functions such as managing and allocating UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notification, etc. The PDU session type may be IP-based, non-IP-based, Ethernet-based, etc.

[0068] The UPF 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via the N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPF 184, 184b may perform other functions, such as routing and forwarding packets, enforcing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering downlink packets, providing mobility anchoring, etc.

[0069] The CN 115 may facilitate communications with other networks. For example, the CN 115 may include or may communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between the CN 115 and the PSTN 108. In addition, the CN 115 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired networks and / or wireless networks owned and / or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, 102c may be connected to local data networks (DNs) 185a, 185b via the UPF 184a, 184b via the N3 interface to the UPF 184a, 184b and the N6 interface between the UPF 184a, 184b and the DN 185a, 185b.

[0070] Given that Figures 1A to 1D as well as Figures 1A to 1D Corresponding to the description of the present invention, one or more or all of the functions described herein with reference to one or more of the following may be performed by one or more simulation devices (not shown): WTRU102a-d, base station 114a-b, evolved Node B 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMF182a-b, UPF 184a-b, SMF 183a-b, DN 185a-b and / or any other device described herein. The simulation device may be one or more devices configured to emulate one or more or all of the functions described herein. For example, the simulation device may be used to test other devices and / or simulate network and / or WTRU functions.

[0071] The simulation device may be designed to implement one or more tests of other devices in a laboratory environment and / or in an operator network environment. For example, one or more simulation devices may perform one or more functions or all functions while being fully or partially implemented and / or deployed as part of a wired and / or wireless communication network in order to test other devices within the communication network. One or more simulation devices may perform one or more functions or all functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network. The simulation device may be directly coupled to another device for testing purposes and / or may use over-the-air wireless communications to perform testing.

[0072] One or more simulation devices can perform one or more (including all) functions without being implemented / deployed as part of a wired and / or wireless communication network. For example, the simulation device can be used in a test scenario in a test laboratory and / or a non-deployed (e.g., testing) wired and / or wireless communication network to implement testing of one or more components. One or more simulation devices can be test equipment. Direct RF coupling and / or wireless communication via RF circuitry (e.g., which can include one or more antennas) can be used by the simulation device to send and / or receive data.

[0073] Systems, methods, and tools for joint transmit (JT) channel state information (CSI) reporting are described herein. The joint transmit CSI may be coherent JT CSI or non-coherent JT CSI. For example, if CSI for multiple transmit / receive points (TRPs) is reported, feedback overhead may be reduced. Precoding matrix indicators (PMI) and / or co-phase information may be reported for TRPs in a JT (e.g., coherent JT or non-coherent JT). A wireless transmit / receive unit (WTRU) may be configured to employ operations to reduce feedback overhead and / or report PMI and / or co-phase information for TRPs in a JT.

[0074] The WTRU may receive CSI reporting configuration information indicating a set of codebook indices (CIs) and a plurality of TRPs. The CSI reporting configuration information may indicate the number of columns in a matrix (e.g., a spatial domain matrix, a frequency domain matrix, etc.) associated with (e.g., each) TRP in the plurality of TRPs. The WTRU may determine PMI information for a subset of TRPs from the plurality of TRPs (e.g., where the subset of TRPs may be determined by the WTRU and / or indicated in the CSI reporting configuration information). The WTRU may determine the PMI information based on receiving and / or measuring an RS (e.g., a CSI-RS). The PMI information may include a channel quality indicator (CQI) value. The WTRU may determine a subset of TRPs (e.g., from a plurality of subsets of TRPs or the plurality of TRPs) based on the PMI information (e.g., a subset of TRPs with the highest CQI value may be selected). The WTRU may determine, for example, based on the configuration information (e.g., CI) that at least two TRPs in the determined subset of TRPs are shared based on the basis (e.g., in the spatial domain and / or frequency domain). The WTRU may transmit a CSI report associated with the selected TRP subset. The CSI report may indicate the determined TRP subset and the determined PMI information associated with the determined TRP subset. The CSI report may include a shared CI associated with the at least two TRPs that are shared on a base basis, for example, to reduce signaling overhead. The CSI report may include a non-shared CI associated with a TRP in the TRP subset that is not shared on a base basis.

[0075] The compression operation may be enhanced, for example, to reduce overhead information. For example, the WTRU may report a basis set (e.g., a spatial basis set, a frequency basis set, a time basis set, etc.) for a coherent JT TRP. The WTRU may be configured to report a compressed basis set. The WTRU may be configured to report a compressed basis set shared by multiple coherent JT TRPs. The WTRU may be configured to report a coefficient set. The WTRU may be configured to report a coefficient set per TRP.

[0076] The WTRU may be configured to generate a basis matrix, for example, for use in PMI calculations. The WTRU may be configured to generate a basis matrix using a basis set from a TRP (eg, a different associated TRP).

[0077] The WTRU may be configured to report CSI. The CSI may include CSI components. The WTRU may be configured to report different CSI component granularities, such as, for example, the number of bases, the number of coefficients, etc. The WTRU may be configured to report different CSI component granularities, for example, for coherent JTTRPs (e.g., different coherent JT TRPs).

[0078] The WTRU may report CSI (e.g., PMI) for a TRP. The WTRU may be configured to receive an indication indicating a set of TRP pairs. The WTRU may be configured to receive configuration information indicating a set of resources associated with the CSI report. The WTRU may be configured to determine the CSI for each TRP pair in the set of TRP pairs. The WTRU may be configured to determine that the set of resources is below a threshold associated with the set of TRP pairs (e.g., the amount of resources in the set of resources is insufficient to accommodate all TRP pairs). The WTRU may be configured to determine a subset of TRP pairs. The subset of TRP pairs may be determined from the set of TRP pairs. The WTRU may be configured to perform measurements (e.g., RSRP) on the TRPs in the set of TRP pairs. For example, if the measurements performed on the TRPs are above a threshold, the WTRU may select a TRP for the TRP subset. The WTRU may be configured to transmit a CSI set. The WTRU may select CSI report content. For example, the WTRU may select CSI report content based on RS groups and / or port groups. The CSI set may include CSI associated with the TRP pairs in the subset of TRP pairs. For example, the WTRU may report CSI for a subset of TRPs for which it has sufficient resources. In an example, the WTRU may report CSI for a secondary TRP, for example, which is dependent on the CSI (e.g., PMI) of the primary TRP.

[0079] The WTRU may be configured to switch between reporting settings. For example, the WTRU may switch between reporting the aggregated PMI for aggregated channels (eg, from a coherent JT TRP) and reporting per-TRP PMI and co-phasing factor.

[0080] The WTRU may determine, for example, a transmission configuration indicator (TCI) for a CSI resource. The TCI may indicate an association between a physical channel (e.g., used for a transmission) and a transmission (e.g., a reference signal transmission, such as a demodulation reference signal transmission) transmitted using the physical channel. The WTRU may determine a TCI per port. The WTRU may determine a TCI per port group for a CSI resource having multiple port groups.

[0081] The channel state information (CSI) reporting framework may be enhanced, for example, to support efficient reporting settings (e.g., for scenarios with multiple TRPs in non-coherent joint transmission (NC-JT)). CSI resources and reporting settings may be enhanced, for example, without changing the codebook (e.g., any codebook).

[0082] Coherent joint transmission (C-JT) may include (e.g., imply) a situation where more than one transmit / receive point (TRP) transmits (e.g., simultaneously) to the WTRU. Data may be available and may be transmitted from the TRPs (e.g., from multiple TRPs at the same time). A pre-decoder may ensure that the signal is received (e.g., coherently) at the WTRU. The pre-decoder may be applied across multiple antennas located at multiple TRPs.

[0083] MIMO may improve CSI acquisition (eg, for frequency division duplex (FDD) C-JT), for example, through enhancements to the Type IICSI reporting framework.

[0084] For example, assuming that the backhaul and synchronization and the number of antenna ports across TRPs (e.g., the same number) are ideal, CSI acquisition can be enhanced for coherent JT (e.g., which targets FR1 and TRPs (e.g., up to four TRPs)). Type II codebook refinement (e.g., for C-JT mTRPs targeting FDD and their associated CSI reports) can be provided, for example, considering the throughput-overhead tradeoff.

[0085] Figure 2 An example of joint transmission from multiple TRPs to a WTRU is illustrated.

[0086] The CSI reporting framework may not be optimized to, for example, report type IICSI for C-JT. (e.g., per) WTRU-TRP link may use (e.g., require) CSI (e.g., accurate CSI) at the network side (e.g., in the case / time of considering C-JT with multiple TRPs, e.g., as Figure 2 , e.g., to implement C-JT with a pre-decoder (e.g., a correctly co-phased pre-decoder). For example, due to the number of CSI components reported in Type II (e.g., a large number), multiple UE-TRP links, and / or different candidate TRP pairs for C-JT, reusing Type II with mTRP may use (e.g., require) CSI reporting overhead (e.g., significant CSI reporting overhead). Feedback for C-JT may be prohibited from being obtained through (e.g., not obtained through) a (e.g., existing) Type II codebook, e.g., because there may not be a standard report associated with co-phase information between TRPs. Co-phasing may be used (e.g., required) on the network side, for example, to pre-decode (e.g., accurately pre-decode) C-JT.

[0087] For example, if type IICSI for multiple TRPs is reported (eg, at this time), feedback overhead may be reduced. Precoding matrix indicator (PMI) and / or co-phase information may be reported for TRPs used for C-JT measurements.

[0088] Beams may be defined. The WTRU may send or receive a physical channel or reference signal according to (eg, at least one) spatial domain filter. The term "beam" may be used to refer to a spatial domain filter.

[0089] The WTRU may transmit a physical channel or signal using the same spatial domain filter as used to receive an RS (e.g., such as a CSI-RS) or synchronization signal (SS) block. The WTRU transmitting may be referred to as a target. The received RS or SS block may be referred to as a reference or source. In this case, the WTRU may transmit (e.g., may be said to transmit) a target physical channel or signal, for example, based on a spatial relationship with reference to such RS or SS block.

[0090] The WTRU may transmit a first physical channel or signal according to the same spatial domain filter as used to transmit a second physical channel or signal. The first transmission may be referred to as a target and the second transmission may be referred to as a reference or source. In this case, the WTRU may transmit (e.g., may be said to transmit) a first (e.g., target) physical channel or signal according to a spatial relationship with reference to a second (e.g., reference) physical channel or signal.

[0091] The spatial relationship may be implicit, e.g., configured by signaling (e.g., RRC signaling), or signaled by a MAC CE or DCI. For example, the WTRU may send (e.g., implicitly send) a PUSCH transmission and / or a DM-RS for a PUSCH transmission according to the same spatial domain filter as the SRS indicated by an SRS resource indicator (SRI) (e.g., indicated in a DCI or configured via signaling (e.g., via RRC signaling). In an example, the spatial relationship may be configured by signaling (e.g., via RRC signaling) for SRI, or may be signaled (e.g., by a MAC CE) for PUCCH transmission. Such a spatial relationship may (e.g., also) be referred to as a beam indication.

[0092] The WTRU may receive a first (e.g., target) downlink channel or signal according to the same spatial domain filter or spatial reception parameters as a second (e.g., reference) downlink channel or signal. For example, such an association may exist between a physical channel (e.g., such as a PDCCH or PDSCH) and its corresponding RS (e.g., DM-RS). For example, such an association may exist when the WTRU is configured with a quasi co-location (QCL) assumption type D between corresponding antenna ports (e.g., at this time) (e.g., at least when the first signal and the second signal are reference signals). Such an association may be configured as a transmission configuration indicator (TCI) state. The WTRU may receive an indication indicating an association between a CSI-RS or SS block and an RS (e.g., DM-RS), for example, by an index associated with (e.g., associated to) a TCI state set configured by signaling (e.g., configured via RRC signaling and / or signaled by a MAC CE). Such an indication may be referred to as a beam indication.

[0093] RS may be used interchangeably with one or more of an RS resource, an RS resource set, an RS port, and / or an RS port group. RS may be used interchangeably with one or more of an SSB, a CSI-RS, an SRS, and / or a DM-RS. TRP (e.g., a transmit and receive point) may be used interchangeably with one or more of a transmit point (TP), a receive point (RP), a radio remote head (RRH), a distributed antenna (DA), a base station (BS), a sector (e.g., a sector of a BS), and / or a cell (e.g., a geographic cell area served by a BS). Multi-TRP may be used interchangeably with one or more of an MTRP, an M-TRP, and / or multiple TRPs.

[0094] Configuration information associated with a TRP, SRI, and / or PL Reference RS may be provided. The WTRU may be configured with or may receive configuration information associated with one or more TRPs (e.g., multiple TRPs), for example, to which the WTRU may send and / or from which the WTRU may receive. The WTRU may be configured with one or more TRPs for one or more cells. A cell may be a serving cell or a secondary cell.

[0095] The WTRU may be configured with an RS (e.g., at least one RS) for, for example, channel measurement. The RS may be represented as a channel measurement resource (CMR). The CMR may include a CSI-RS, SSB, or other downlink RS sent from a TRP to the WTRU. The CMR may be configured with a TCI state or associated with a TCI state. The WTRU may be configured with a CMR group or RS group (RSG) that may include, for example, CMR indexes sent from the same TRP. (e.g., each) group may be identified by a CMR group index (e.g., group 1). The WTRU may be configured with one CMR group per TRP. The WTRU may receive a link between (e.g., one) CMR group index and another CMR group index or between (e.g., one) RS index from one CMR group and another RS ​​index from another group. The WTRU may determine that the linked resources may be configured for C-JT MTRP channel and / or CSI measurement.

[0096] The WTRU may be configured with or receive configuration information associated with one or more path loss (PL) reference groups (eg, sets) and / or one or more SRS groups, SRS resource indicators (SRIs), and / or SRS resource sets.

[0097] A path loss (PL) reference group may correspond to or may be associated with a TRP. A PL reference group may include, identify, correspond to, and / or be associated with one or more TCI states, SRIs, reference signal sets (e.g., CSI-RS sets, SRI sets), CORESET indices, and / or reference signals (e.g., CSI-RS, SSBs, etc.).

[0098] The WTRU may receive configuration information (e.g., any configuration information as described herein). The configuration information may be received from a base station (e.g., a gNB) or a TRP. For example, the WTRU may receive configuration information associated with one or more TRPs, one or more PL reference groups, and / or one or more SRI sets. The WTRU may determine (e.g., implicitly determine) an association between an RS set / group and a TRP. For example, if the WTRU is configured with multiple (e.g., two) SRS resource sets, the WTRU may transmit to TRP1 using SRS in a first resource set (e.g., determine to transmit) and transmit to TRP2 using SRS in a second resource set (e.g., determine to transmit). The configuration information may be received via signaling (e.g., RRC signaling).

[0099] The WTRU may receive an indication of a primary TRP and a secondary TRP. For example, in the event that the WTRU is configured with multiple TRPs (e.g., at this time), the WTRU may determine whether one of the TRPs is the primary TRP or the anchor TRP. This designation may be based on network configuration or WTRU determination (e.g., the received signal quality of one TRP is higher than the received signal quality of all other TRPs, or is higher than a threshold).

[0100] TRP, PL reference set, SRI set, and SRI collection may be used interchangeably (eg, as described herein). The terms "collection" and "group" may be used interchangeably (eg, as described herein).

[0101] A coherent joint transmission system with multiple (e.g., two) TRPs may be considered. These operations and / or processes (e.g., as described herein) may be used in situations with more than two TRPs. In an example, one of the TRPs may be considered a primary TRP.

[0102] Grant or assignment attributes may be provided. The attributes of a grant or assignment may include one or more of the following: frequency allocation; aspects of the time allocation, such as duration; priority; modulation and coding scheme; transport block size; number of spatial layers; number of transport blocks; TCI state, CRI, or SRI (e.g., where the TCI state, CRI, or SRI may be used for each WTRU panel if, for example, multiple panels are used for UL transmissions); number of repetitions; whether the repetition scheme is Type A or Type B; whether the grant is a configured grant Type 1, Type 2, or a dynamic grant; whether the assignment is a dynamic assignment or semi-persistent scheduling (configured (configured) assignment; configured grant index or semi-persistent assignment index; configured periodicity of grant or assignment; channel access priority class (CAPC); any parameters provided by signaling (e.g., in DCI, by MAC signaling, or by RRC signaling) for scheduling grants or assignments; whether the grant is for single TRP transmission or multiple TRP transmissions; whether the grant is for UL transmissions from a single WTRU panel (TxSP) or simultaneous UL transmissions from multiple WTRU panels (STxMP); whether the grant is for C-JT or non-coherent joint transmission (NC-JT).

[0103] CSI components may be provided and / or reported. The WTRU may report a subset of channel state information (CSI) components, for example, where the CSI components may correspond to one or more of: a CSI-RS resource indicator (CRI), an SSB resource indicator (SSBRI), an indication of a panel for reception at the WTRU (e.g., such as a panel identifier or a group identifier), measurement results (e.g., such as L1-RSRP, L1-SINR (e.g., cri-RSRP, cri-SINR, ssb-Index-RSRP, ssb-Index-SINR) obtained from SSB or CSI-RS), and / or other channel state information (e.g., such as at least a rank indicator (RI), a channel quality indicator (CQI), a precoding matrix indicator (PMI) (e.g., which may include CI (e.g., spatial domain CI, frequency domain CI, etc.), such as Figure 3 as shown) and / or layer index (LI), etc.).

[0104] Compression enhancement may be provided. Compression may be enhanced. Precoding (e.g., high resolution precoding) may be composed of components (e.g., several components). The high resolution precoding mechanism may be based on multiple CSI components, for example, the multiple CSI components include one or more of the following: wideband (W1), narrowband (W2), and / or at least one (e.g., one) set of basis vectors for compression (e.g., W_comp1, W_comp2, etc.).

[0105] In an example, a high-resolution precoding mechanism may be associated with type IICSI (e.g., wideband CSI (W1), narrowband CSI (W2), and frequency domain compression based on Wf). W1 may represent a set (e.g., a preferred set) of beams (e.g., dual polarization beams) for (e.g., each) MIMO transmission layer. The structure of W1 may be composed of a matrix having L1 columns corresponding to L1 spatial beams (e.g., L1 basis vectors) and R rows corresponding to the basis length (e.g., where the number of columns may be associated with a TRP from a plurality of TRPs, such as Figure 3 As shown). The set of spatial beams used to construct W1 can be defined as the spatial basis of the beam. W1 can represent the orthogonal polarizations of the configured transmit antennas based on a block diagonal structure. The W1 CSI may include wideband coefficients to indicate the power setting of each beam (e.g., the preferred power setting of each beam). The W2 CSI may include amplitude information (e.g., additional amplitude information) and co-phase information (e.g., additional co-phase information), for example, to indicate the preferred linear beam combination for each subband.

[0106] The subband information may be compressed in the frequency domain (eg, by indicating a subset of the L2 basis compressed vectors in the matrix Wf, and a dominant set of coefficients), for example, to reduce overhead information associated with the indication of the subband information.

[0107] A set of L3 compressed vectors in the time domain Wt and (e.g., one) coefficient per vector in Wt may be considered. The WTRU may also reduce CSI reporting overhead, for example, by compressing a set of N samples in the time domain into a set of L3 time compressed vectors Wt.

[0108] In summary, the WTRU may report (e.g., one) set of compressed vectors in space, (e.g., one) set of compressed vectors in frequency, (e.g., one) set of compressed vectors in time, (e.g., one) coefficient per compressed vector in space, (e.g., one) coefficient per compressed vector in frequency, and / or (e.g., one) coefficient per compressed vector in time. The WTRU may report (e.g., each) coefficient as an index of magnitude and phase elements, for example, where the elements may be derived from a codebook of quantized magnitude and phase elements.

[0109] The WTRU may report, for example, CSI feedback for C-JT. A high-resolution precoding mechanism may be used in multi-TRP CJT transmissions. Figure 3 An example of CSI reporting for multi-TRP CJT is illustrated. The WTRU may receive a grant (e.g., dynamically receive a grant in a DCI, or receive a grant pre-configured in a CG) that indicates an mTRP scheduling using an indicator (e.g., an explicit indicator) of a C-JT from more than one TRP (e.g., multiple TRPs) and an index of the TRP (e.g., a codebook index (CI)). The WTRU may receive data (e.g., a PDSCH transmission) transmitted from an mTRP with a C-JT pre-decoder, for example, where the pre-decoder (e.g., PMI information) is determined based on WTRU feedback (e.g., the PMI information may be determined based on a subset of TRPs from the multiple TRPs, such as Figure 3 As shown). Direct use of the feedback mechanism per TRP may result in an increase (e.g., a significant increase) in the uplink CSI feedback channel. In order to limit the increase in uplink control channels, one or more of the following methods may be used in a multi-TRP CJT system.

[0110] The WTRU may report a (e.g., one) base set shared by multiple TRPs (e.g., Figure 3 In an example, basic sharing may refer to an operation whereby the WTRU may report (e.g., in a CSI report) a set of (e.g., one) basis vectors (e.g., spatial, frequency, or time) that may be associated with more than one TRP (e.g., shared by more than one TRP) (e.g., the WTRU may report PMI information including a shared CI for a basic shared TRP (e.g., at least two TRPs determined to be basic shared)). The WTRU may, for example, based on received CSI configuration information (e.g., as Figure 3 The CJT type IICSI reporting configuration information shown in the figure determines that at least two TRPs are determined to be shared as a basis (e.g., in the spatial domain, frequency domain, etc.). For example, (e.g., rather than reporting one W1 / Wf / Wt per TRP), the WTRU may report: (e.g., one) W1 / Wf / Wt for TRP1 and TRP2; and (e.g., one) W2, frequency, and time coefficients per TRP, respectively. In this case, the WTRU may report (e.g., allegedly report) shared W1 / Wf / Wt (e.g., shared CI) for TRP1 and TRP2.

[0111] The WTRU may generate a CSI report, for example, where (e.g., one) set of basis compression vectors (e.g., a shared set of basis compression vectors, a shared CI, etc.) may be associated to multiple TRPs. The WTRU may indicate (e.g., explicitly) a TRP pair (e.g., a TRP pair that shares basis compression vectors) in the CSI report. For example, the WTRU may indicate that TRP1 and TRP2 share the same set of L bases and the L bases reported. The WTRU may report CSI for TRP1 and TRP2 using the same L bases in a single CSI report and report per-TRP coefficients. This may be applied in the spatial / frequency / time domain (e.g., as Figure 3 as shown), where one of the following may apply: the WTRU may indicate a shared (e.g., the same) set of spatial basis compression vectors W1 for (e.g., only) more than one TRP; the WTRU may indicate a shared (e.g., the same) set of time basis compression vectors Wt for more than one TRP; the WTRU may indicate the same set of frequency basis compression vectors Wf for more than one TRP.

[0112] The WTRU may report CSI while utilizing basic sharing, for example, based on receiving an indication (e.g., a flag) to activate / deactivate basic sharing. In an example, the WTRU may receive a flag to activate basic sharing. If the flag is turned on, the WTRU may generate its CSI report while utilizing basic sharing between more than one TRP (e.g., one basis for multiple TRPs). If the flag is turned off, the WTRU may generate its CSI report without utilizing basic sharing (e.g., one basis per TRP).

[0113] The WTRU may receive an indication (eg, a flag) as part of a bit field in the CSI reporting configuration information. The WTRU may receive signaling (eg, via an RRC reconfiguration signal) of the CSI reporting configuration information to activate / deactivate the flag.

[0114] The WTRU may receive an indication (e.g., a flag) as part of uplink resource configuration information for reporting CSI. For example, (e.g., one) PUCCH resource may be configured for reporting CSI with a shared basic component. The WTRU may determine to generate a CSI report with basic sharing turned on, for example, based on a PUCCH resource index (PRI).

[0115] The WTRU may receive more than one PRI and may determine to use multiple PRIs to report shared CSI. The WTRU may determine the association between the PRI and the TRP and may report CSI on the associated PUCCH resources.

[0116] For example, if the WTRU reports on PUSCH, the WTRU may (e.g., alternatively) receive a grant for an mTRP PUSCH transmission toward multiple TRPs. The WTRU may report CSI for the same TRP on a PUSCH transmission associated to a TRP (e.g., a PUSCH repetition of an SRI with a CSI report for the associated TRP).

[0117] For example, if the number of configured TRPs or TRP pairs is above a threshold, the WTRU may (e.g., alternatively) report a sharing basis. For example, if the WTRU reports CSI for (e.g., one) TRP pair, the WTRU may refrain from using basic sharing (e.g., not using basic sharing). If the WTRU reports CSI for more than one TRP pair, the WTRU may use basic sharing between TRPs within a pair or across pairs.

[0118] If the WTRU is configured with more than one TRP, or if the WTRU is configured to report with more than one TRP pair, the WTRU may receive more than one flag (e.g., where the flags may form a bitmap indicating which TRPs are to have basic sharing activated). For example, the WTRU may be configured with TRP1, TRP2, and TRP3 and a bitmap associated with each pair ({TRP1, TRP2}, {TRP1, TRP3}, {TRP2, TRP3}). The WTRU may receive a flag 100 that may indicate that sharing is activated when reporting CSI between {TRP1, TRP2} (e.g., at this time) and that sharing is disabled (e.g., no sharing) when reporting CSI for the pairs {TRP1, TRP3}, {TRP2, TRP3} (e.g., at this time).

[0119] The flag may (e.g., alternatively) be associated to a TRP, e.g., such that any report including the TRP, the indicated TRP index may include the base sharing. For example, the flag may be activated for TRP1, and the WTRU may report CSI with base sharing between any TRP pair including TRP1 (e.g., TRP1-TRP2 and TRP1-TRP3).

[0120] The WTRU may determine a subset of TRPs or a subset of TRP pairs for which to report sharing (e.g., based on PMI information or CQI values, for example, where a first subset of TRPs is determined to have a first CQI value and a second subset of TRPs is determined to have a second CQI value and the first CQI value is higher than the second CQI value, such as Figure 3 For example, the WTRU may receive CSI reporting configuration information indicating that basic sharing is enabled (e.g., turned on), that multiple TRPs are configured, and / or an indication that (e.g., only) one pair is reported. The WTRU may calculate CSI for multiple pairs and may select a pair (e.g., one pair) from the multiple pairs to report (e.g., based on determining a CQI value, such as Figure 3 ). The WTRU may include the index of the selected TRP or TRP pair (e.g., CI) together with the CSI in the CSI report.

[0121] The WTRU may report parameter resolutions (e.g., different parameter resolutions) per TRP (e.g., space, frequency, time). In an example, the WTRU may reduce CSI feedback overhead in multi-TRP CJT by using one or more of the following: The WTRU may indicate the number (e.g., maximum number) of spatial beams per TRP (e.g., L1, L2, etc.), where the number of beams (e.g., total number) may be specified, semi-statically configured, or dynamically indicated; The WTRU may indicate (e.g., preferred) wideband amplitude, subband amplitude, and / or co-phase information for cross-TRP beam combining.

[0122] For example, the WTRU may indicate a (e.g., maximum) number of spatial beams per TRP (e.g., L1, L2, etc.), where the total number of beams may be specified, semi-statically configured, or dynamically indicated. The WTRU may receive CSI report setting configuration information, for example, where the maximum number of beams per TRP is configured. The WTRU may determine PMI feedback, for example, based on the number of beams. The WTRU may (e.g., alternatively) select and indicate the number of beams per TRP for W1, for example, based on one or more of: the angular position of the WTRU relative to each TRP; signal quality measurements (e.g., RSRP, etc.); direction of movement (e.g., approaching or leaving relative to each TRP); and / or a CSI report that may include a (e.g., one) field (e.g., a new field) per TRP for the WTRU to indicate the selected maximum number of beams to the WTRU. The WTRU may receive signaling (e.g., via MAC-CE) that may activate or update the number of beams per TRP.

[0123] The WTRU may indicate (e.g., preferred) wideband amplitude, subband amplitude, and co-phase information, for example, for use in cross-TRP beam combining. In an example, the WTRU may indicate a (e.g., preferred) set of wideband amplitude, subband amplitude, and co-phase information for combining a first set of beams from a first TRP with another set of beams from a second TRP.

[0124] In an example, the WTRU may select and may indicate different resolutions of quantization amplitude and common-phase information for each TRP. The WTRU may select the resolution per TRP, for example, based on the type of TRP, the cell, etc. For example, the WTRU may select a higher resolution quantization amplitude and common-phase information for a primary TRP than the quantization amplitude and common-phase information for other TRPs.

[0125] The WTRU may select the resolution per TRP based on signal quality measurements (e.g., RSRP, etc.) For example, higher resolution quantized magnitude and co-phase information may be used for TRPs corresponding to stronger signals at the WTRU.

[0126] The WTRU may select a quantization resolution per TRP, for example, based on the layers or codewords sent from each TRP. For example, the WTRU may report CSI using higher resolution quantized amplitude and common-phase information for the first and second layers sent from the master TRP and lower resolution quantized amplitude and common-phase information from other TRPs. The WTRU may (e.g., alternatively) select a quantization resolution per TRP, for example, based on the (e.g., total) number of layers or codewords sent from each TRP. For example, the WTRU may report CSI using a first quantization resolution for amplitude and common-phase information sent for four layers from the first TRP and a second quantization resolution for amplitude and common-phase information sent for two layers from other TRPs.

[0127] In an example, the WTRU may select and may indicate a combination of wideband and subband CSI for each TRP (e.g., different combinations). In an example, the WTRU may report both wideband and subband information for a first TRP, and (e.g., only) wideband CSI for a second TRP. The WTRU may report CSI by using wideband amplitude and co-phase information and narrowband amplitude and co-phase information (e.g., both). The number of subbands used for narrowband CSI reporting may be different for each TRP. The WTRU may receive these combinations as part of the CSI reporting configuration information.

[0128] The WTRU may indicate a (e.g., shared or same) set of basis compression vectors for more than one TRP (e.g., for frequency domain compression, etc.). The WTRU may use (e.g., different) frequency domain units for each TRP. For example, the WTRU may consider multiple (e.g., two) frequency units per subband for subband CSI compression for a first TRP, and consider (e.g., a single) frequency unit per subband for subband CSI compression for a second TRP. Similarly, for spatial compression or temporal compression, the WTRU may report a different number of coefficients per TRP while reporting a shared (e.g., same) set of basis compression vectors for a TRP (e.g., all TRPs). In an example, for a first TRP, the WTRU may (e.g., alternatively) perform frequency domain compression and report subband CSI for a subband (e.g., all subbands), and for a second TRP, the WTRU may perform frequency domain compression and report subband CSI for (e.g., only for) a (e.g., selected) set of subbands (e.g., odd or even subbands). For each CSI report, the WTRU may alternate CSI information for odd / even subbands. For example, the WTRU may include odd subband information in the first CSI report, and in the second CSI report T seconds later, the WTRU may include even subband information.

[0129] The WTRU may report different CSI resolutions, for example, depending on the operating mode (e.g., sTRP / mTRP operating mode).

[0130] In an example, the WTRU may determine the resolution / number of bases to report based on the indicated sTRP / mTRP mode. The WTRU may receive CSI reporting configuration information indicating multiple (e.g., two) configuration sets, for example, where (e.g., one) configuration information set may be used for sTRP CSI reporting and another configuration information set may be used for mTRP C-JT CSI reporting. For example, the WTRU may receive configuration information having an L_sTRP basis for sTRP CSI reporting and an L_mTRP basis for mTRP CSI. The L_mTRP may consist of a subset of all L bases, or of the configured L_sTRP basis. In mTRP mode, the WTRU may determine its CSI by considering (e.g., only considering) a pair formed by an L_mTRP1 basis from TRP1 and an L_mTRP2 basis from TRP2. For example, the WTRU may calculate CSI for TRP1 using W1 formed using L_mTRP1 basis and calculate CSI for TRP2 using W1 formed using L_mTRP2 basis, for example, where both basis sets are associated for C-JT CSI reporting.

[0131] The WTRU may report CSI that depends on W (e.g., a matrix) constructed using a basis set from TRPs (e.g., more than one TRP). In an example, the WTRU may construct a basis matrix using (e.g., one) parameter set from one TRP and another parameter set from another TRP, and may generate a CSI report based on the basis matrix. For example, the WTRU may generate a W1 matrix of beams using a B1 beam from TRP1 and a B2 beam from TRP2. The first B1 columns of the W1 matrix may include TRP1 beams, and the next B2 columns may include TRP2 beams. The WTRU may generate a PMI based on the W1 matrix. The WTRU may receive an indication of a TRP (e.g., multiple TRPs) and / or a number and index of beams per TRP used to construct W1 in a CSI reporting setup (e.g., CSI reporting configuration information). The WTRU may report a W2 index per TRP.

[0132] The WTRU may determine to generate a shared W1 matrix, for example, based on an indication (e.g., a flag). For example, if the WTRU receives an on flag, the WTRU may use the indicated beams from TRP1 and TRP2 to construct W1. For example, if the WTRU receives an off flag, the WTRU may use (e.g., only use) a basis set of the corresponding TRP to generate one W1 per TRP.

[0133] The WTRU may report CSI, for example, based on RS configuration information, while utilizing basic sharing. The WTRU may, for example, activate (e.g., determine to activate) (e.g., any) operation as described herein (e.g., basic sharing, W1 construction) based on RS configuration information associated with the CSI reporting configuration information. For example, the WTRU may receive CSI reporting configuration information, for example, where the CSI-RS may be configured with ports associated to multiple (e.g., two) different TRPs (e.g., a CSI-RS resource CRI1 with two ports, where port 1 is transmitted from TRP1 and port 2 is transmitted from TRP2). The WTRU may determine (e.g., implicitly determine) that such CSI-RS configuration information associated with more than one TRP may be associated with configuration information for mTRP reporting with sharing enabled. The WTRU may (e.g., alternatively) receive TCI code points with more than one TCI state, configuration information with RSs from different TRPs linked together, or TCI states from different TRPs linked together.

[0134] The WTRU may determine the association between the port group and the TCI state.

[0135] A (e.g., one) CSI-RS resource (e.g., associated to multiple TPRs) may be configured with multiple port groups (PGs). (E.g., each) PG may contain (e.g., multiple) ports from a (e.g., single) TRP. The WTRU may determine an association (e.g., a one-to-one association) between a PG and a TCI (e.g., for a CSI-RS resource with multiple PGs) to, for example, receive PG 1 with TCI state 1 and PG 2 with TCI state 2. The WTRU may determine the TCI state based on measurements (e.g., using a CSI-RS with a (e.g., single) PG. For example, the WTRU may receive (e.g., one) CSI-RS resource with a (e.g., single) PG, where (e.g., all) ports are associated with (e.g., belong to) TRP1. The WTRU may determine that PG 1 is associated with TCI1. The WTRU may receive a second CSI-RS resource with (e.g., multiple) PGs, where the PG (e.g., one of the PGs) is PG 1. The WTRU may determine that ports in the second CSI-RS resource with PG 1 may be associated with TCI1. The WTRU may receive configuration information indicating that the first CSI-RS resource is the source RS for TCI1 for PG 1. The WTRU may use (e.g., different) spatial receive filters for (e.g., each) group of ports (e.g., if the ports are transmitted in different time slots or if the ports are received on different panels).

[0136] The WTRU may (e.g., alternatively) determine a many-to-one association between PGs and TCI states, for example, to receive CSI-RS with more than one PG having a (e.g., single) TCI state. The WTRU may determine the TCI state by receiving CSI-RS with multiple PGs. The WTRU may determine the (e.g., single) TCI state to receive PG 1 and PG 2. The WTRU may use a (e.g., single) spatial receive filter for a port group (e.g., two port groups).

[0137] Figure 4 Example types of associations between TCI states and PGs are illustrated. In an example (e.g., for a one-to-one case), the WTRU may receive CSI-RS configuration information indicating (e.g., two) TCI states (e.g., two TCI states are configured). The (e.g., two) PGs may be configured to associate antenna ports to TCI states, e.g., such that each TRP / TCI is associated to (e.g., one) corresponding PG. In an example (e.g., with respect to a many-to-one association), PGs (e.g., two PGs) may be associated to the same TCI state.

[0138] The WTRU may receive signaling (e.g., MAC-CE) indicating reconfiguration of PG associations per CMR. The WTRU may receive signaling (e.g., MAC-CE) indicating activation of different TCI states per port of a CSI-RS resource. The signaling (e.g., MAC-CE) may include a bitmap having a length associated with the number of ports (e.g., equal to the number of ports) and one TCI state for each bit in the bitmap equal to 1. For example, the WTRU may receive 1010 for a CSI-RS resource with 4 ports and TCI states 1 and 2. The WTRU may (e.g., expect) to receive CSI-RS with ports 1 and 3 from a TRP associated with TCI states 1 and 2.

[0139] In an example (e.g., for a one-to-one case), the WTRU may receive signaling (e.g., MAC-CE) indicating an update of the TCI state per PG or two PGs. The signaling (e.g., MAC-CE) may include one or two TCI states and the index of the PG associated with (e.g., each) TCI state update. The signaling (e.g., MAC-CE) may update the PG index association to the antenna port. For example, the WTRU may receive a control message to change PG 2 to PG 3 (e.g., change TRP2 to TRP3). The WTRU may change its spatial receive filter for PG3. The WTRU may receive a control message indicating a change in the number of ports per PG and the number of PGs per CSI-RS resource (e.g., 2 PGs with 8 ports per group may be updated to 4 PGs with 4 ports per group).

[0140] CSI assessments and reports may be conditional.

[0141] The WTRU may provide CSI information to a base station (e.g., gNB) to assist in more accurate downlink precoding, for example, in a JT system. The WTRU may use different transmission assumptions and / or assumptions to determine and report CSI, for example, depending on whether coherent JT or non-coherent JT is used.

[0142] The WTRU may not be aware of the results of the CSI estimate (e.g., the WTRU's reported estimate). The WTRU may report CSI that may be ignored by the base station (e.g., gNB) due to other scheduling constraints (e.g., such as inter-interference and / or intra-interference), for example, because the WTRU may not be aware of (e.g., is not aware of) the channel and spatial information of other WTRUs.

[0143] The WTRU may calculate the CSI based on a set of parameters (eg, a constrained set of parameters) that depends on a set of parameters from the primary TRP.

[0144] In a multiple TRP transmission scenario, CSI reporting for channels (e.g., all channels) corresponding to a TRP (e.g., all TRPs) may use (e.g., require) a certain amount (e.g., excessive) of uplink feedback overhead. Some constraints in the CSI reporting may reduce (e.g., help reduce) the uplink feedback overhead and the overall spectral efficiency of the system. In an example, the WTRU may receive an indication that the WTRU assumes a particular subset of transmission characteristics (e.g., beams or PMIs for one TRP that will be used to estimate CSI for other TRPs). The WTRU may receive such constraints as a list of allowed or disallowed ranges for characteristic parameters for CSI estimation.

[0145] In an example (e.g., for a given WTRU), a base station (e.g., gNB) may refrain from using (e.g., avoid using) one or more transmit features (e.g., one or more of certain transmit features) that may impair transmissions to another WTRU. For example, a base station (e.g., gNB) may refrain from using (e.g., certain) beam directions and / or precoding selections (e.g., due to interference that may be imposed on another WTRU). A base station (e.g., gNB) may refrain from (e.g., refrain from) transmitting to a first WTRU with more than a certain number (e.g., a particular number) of layers to leave spatial degrees of freedom (e.g., sufficient spatial degrees of freedom) for transmissions to a second WTRU, which may have similar spatial properties as a first WTRU in the system. A WTRU may be instructed to refrain from providing (e.g., not providing) CSI estimates corresponding to higher order modulations, for example, to reduce base station (e.g., gNB) power transmissions.

[0146] In an example, a WTRU may receive an indication indicating (eg, including) a set of transmit features (eg, a constrained set of transmit features) to be used by the WTRU for CSI estimation and / or reporting. The WTRU may receive an indication indicating that one or more of the following are excluded for its CSI reporting: beam direction, for example, the beam direction may be indicated by a set of indices associated with one or more configured reference signals (e.g., CRI, SSBRI, etc.); precoding matrix, for example, the precoding matrix may be indicated by a set of indices (e.g., a precoding matrix indicator or PMI); polarization, for example, the polarization may be explicitly indicated by an index used to signal a specific polarization for transmission (e.g., V vs. H, +45 vs. -45, linear vs. circular, etc.); layer, for example, the layer may be indicated by an indicated rank as the highest allowed rank for CSI estimation (e.g., alternatively, the particular subset of layers may be constrained based on their relative channel eigenpower, such as the first two layers corresponding to the strongest eigenmodes of the channel); and / or modulation, for example, the modulation may be indicated by one or more of the MCSs as the highest allowed modulation order for CSI estimation.

[0147] The WTRU may receive an indication indicating such a constraint for one or more TRPs in the system. The WTRU may be configured with (e.g., multiple) CSI constraint settings. The WTRU may be dynamically indicated to use one of the configured settings. The WTRU may receive and apply different constraints per TRP. For example, the WTRU may receive and apply configuration information associated with CSI_restriction_1 for a first TRP and CSI_restriction_2 for a second TRP.

[0148] In an example, the WTRU may receive a period (e.g., a valid period) for a CSI constraint setting. For example, the WTRU may receive an indication (e.g., a first / start indication) to start using the indicated CSI constraint setting, and another indication (e.g., a second / stop indication) to terminate the use of the indicated CSI constraint setting. The start / stop indication may refer to the receipt of a CSI request trigger or another reference point, such as an SSB position, etc. The WTRU may (e.g., alternatively) receive a time and / or frequency pattern to determine what CSI constraint setting to use for a given time and / or frequency resource.

[0149] The WTRU may select a configured CSI constraint setting (e.g., one of the configured CSI constraint settings), for example, based on another criterion. The WTRU may determine the CSI constraint setting based on one or more of: measured signal quality (e.g., SNR, RSRP, Doppler, etc.), for example, if it meets a pre-configured threshold; TRP state (e.g., primary or secondary, serving or non-serving, cell type, etc.); and / or TRP transmit capability. The WTRU may determine the CSI constraint setting based on the TRP transmit capability, based on one or more of: the number of transmit ports indicated for each TRP; single TRP transmit mode vs. multiple TRP transmit mode; operating frequency band or bandwidth portion (e.g., band_x or band_y); power transmit rating; FR1 vs. FR2; coherent capability vs. incoherent capability of the transmit; and the like.

[0150] For example, if (e.g., upon) the WTRU selects one of the configured CSI constraint settings, the WTRU may (e.g., implicitly or explicitly) indicate the CSI constraints used. The WTRU may report an index to indicate the CSI constraint configuration information used, for example, where the index may be part of the reported CSI (e.g., a flag in the MAC CE header or UCI payload). If CSI is reported per TRP, an indication of the CSI configuration settings used for other TRPs may be indicated as part of the CSI reported for the primary TRP. The WTRU may (e.g., alternatively) indicate the selected CSI configuration setting for each CSI payload independently.

[0151] The WTRU may indicate (e.g., implicitly indicate) the adopted CSI constraint setting by selecting a pre-configured uplink resource. For example, the WTRU may indicate the selection of a first setting by transmitting on a first configured uplink control resource and may indicate the selection of a second setting by transmitting on a second configured uplink resource.

[0152] The WTRU may dynamically switch between single TRP operation and multi-TRP operation. The WTRU may select one of the configured CSI settings, for example, depending on whether the WTRU is operating in single TRP mode or multi-TRP mode. In an example, the WTRU may use a first CSI constraint setting for a primary TRP in multi-TRP mode and may use another (e.g., second) setting for the same TRP (e.g., if / when it is operating in single TRP mode).

[0153] The WTRU may include / exclude (e.g., dynamically include / exclude) CSI parameters, for example, based on the configured TRP pairs.

[0154] For example, in the case of performing CSI reporting (e.g., at this time), for example, based on (e.g., according to) which TRP pairs are selected (e.g., as best, as described herein), the WTRU may apply (e.g., be configured to apply) inclusion / exclusion (e.g., dynamic or semi-static inclusion / exclusion) of PMI / CRI for TRPs. The WTRU may determine (e.g., in a CSI reporting instance) one or more TRPs (e.g., best / preferred TRPs) for communication (e.g., based on the determined PMI information associated with the one or more TRPs). The one or more (e.g., best / preferred) TRPs for communication may include TRP1 and TRP2 (e.g., a subset of TRPs from the multiple TRPs). The proposed operations and / or processes (e.g., as described herein) may be similarly used in the case where more than two TRPs are selected as the one or more (e.g., best / preferred) TRPs. In the example, one of the TRPs may be a primary TRP (e.g., TRP1).

[0155] The selection of TRP1 and TRP2 may be indicated, for example, based on CRI, CSI-RS resource set ID / index, different sets of CSI-RS antenna ports (APs) in the CSI-RS resource, TRP ID / index, and / or PMI reported by the WTRU, for example, in a CSI reporting instance. In an example, the WTRU may report (e.g., at least) a first CRI value (e.g., CSI-RS resource 7) and a second CRI value (e.g., CSI-RS resource 13), each corresponding to TRP1 and TRP2, respectively. For example, via signaling (e.g., such as via RRC signaling and / or MAC-CE signaling) or in a predefined / predetermined rule, one or more first CRIs (e.g., including at least the first CRI value, e.g., included in the CSI-RS resource set ID and / or the like) may correspond to (e.g., be associated with) TRP1. For example, via signaling (e.g., such as via RRC signaling and / or MAC-CE signaling) or in a predefined / predetermined rule, one or more second CRIs (e.g., including at least a second CRI value, e.g., included in a CSI-RS resource set ID and / or the like) may correspond to (e.g., be associated with) TRP2. For example, in addition to the reported CRI value, the WTRU may also report (e.g., at least) a first PMI value (e.g., PMI=4 in the codebook) and a second PMI value (e.g., PMI=11 in the codebook).

[0156] A pair (e.g., one or more pairs) of CSI-RS resources (e.g., a first CRI value and a second CRI value) corresponding to each TRP may be predefined (e.g., identified, determined), for example, for including / excluding (e.g., dynamically or semi-statically including / excluding) a PMI / CRI for the TRP. A pair (e.g., one or more pairs) of CSI-RS resources (e.g., a first CRI value and a second CRI value) corresponding to each TRP may be indicated (e.g., explicitly indicated) or configured to the WTRU, for example, for dynamically or semi-statically including / excluding a PMI / CRI for the TRP. In an example, the WTRU may first determine (e.g., select) a first CRI value for TRP1 (e.g., as a primary TRP). In response to determining the first CRI value, the WTRU may determine that the first CRI value is included in the pair of CSI-RS resources. In response to determining that the second CRI value is included in the pair of CSI-RS resources, the WTRU may determine (e.g., select) a second CRI value for TRP2 (e.g., not being allowed to select other CRI values ​​for TRP2, but only selecting CRI values ​​within the pair of CSI-RS resources), which may be interpreted as an example of dynamically or semi-statically including / excluding CRI for TRP. This may provide the following benefits: (e.g., based on geographic TRP distribution / deployment and network / cell planning) a base station (e.g., gNB) may configure one or more candidate CRI pairs that can be selected by the WTRU, for example, so that operational complexity may be reduced and / or downlink performance / efficiency based on CRI reporting may be improved.

[0157] Pairs (e.g., one or more pairs) of a first set of one or more CSI-RS APs and a second set of one or more CSI-RS APs in a CSI-RS resource may be predefined (e.g., identified, determined) for dynamically (or semi-statically) including / excluding PMI / CRI for a TRP, wherein the one or more pairs may be configured via signaling (e.g., such as RRC signaling, and / or activated via MAC-CE and / or indicated by DCI). In an example, the WTRU may report (e.g., at least) a first PMI value determined based on the first one or more CSI-RS APs (e.g., PMI=6 in the codebook) and a second PMI value determined based on the second one or more CSI-RS APs (e.g., PMI=17 in the codebook), for example, each PMI value corresponding to each TRP. This can provide the following benefits: (e.g., based on geographic TRP distribution / deployment and network / cell planning) a base station (e.g., gNB) can configure one or more candidate CSI-RS AP pairs in the CSI-RS resources (e.g., each AP set corresponds to or is associated with each TRP), for example, so that operational complexity can be reduced and / or downlink performance / efficiency based on CRI reporting can be improved.

[0158] The WTRU may be configured (e.g., activated, indicated) with one or more candidate codebook subset constraint (CBSR) sets, for example, to dynamically or semi-statically include / exclude PMI / CRI for a TRP (e.g., for a secondary TRP in addition to a primary TRP). The one or more CBSR sets may be semi-statically indicated / configured from the gNB, for example, via signaling (e.g., such as via RRC signaling and / or MAC-CE signaling). The one or more CBSR sets may be dynamically indicated from the gNB, for example, via MAC-CE and / or DCI. In an example, the WTRU may be configured (e.g., activated, indicated) with CBSR Set 1, CBSR Set 2, CBSR Set 3, etc. The CBSR set (e.g., one of CBSR Set 1, CBSR Set 2, CBSR Set 3, etc.) may be associated with one or more first PMIs for TRP1 (e.g., primary TRP) (e.g., based on configuration information / indication of the gNB). The WTRU may (e.g., first) select / determine a first PMI (e.g., a W1 matrix including beam candidates) from the one or more first PMIs, for example, for use in a CSI reporting instance, which may be the best / preferred PMI for communication with TRP1. The WTRU may be permitted to determine / select the one or more first PMIs based on a CSI-RS resource or a set of CSI-RS resources associated with a TRP (e.g., TRP1). Based on determining the first PMI, the WTRU may determine that the first PMI has an association with one of the CBSR sets (e.g., configured CBSR sets). For example, the WTRU may determine that the first PMI has an association with CBSR set 3. In response to determining that the first PMI has an association with one of the CBSR sets, the WTRU may determine (e.g., select) a second PMI (e.g., a W1 matrix (e.g., including beam candidates)) from one or more second PMIs within CBSR set 3 (e.g., where the WTRU is prohibited from selecting (e.g., not permitted to select) a second PMI that is not within CBSR set 3 (e.g., outside of the CBSR set)). This can provide benefits in that the WTRU can determine a second PMI within CBSR set 3 (e.g., for TRP2, associated with TRP2) based on a first PMI determined by the WTRU (e.g., first) for TRP1 (e.g., the primary TRP), for example, such that operational complexity can be reduced (e.g., for MTRP scenarios) and / or downlink performance / efficiency based on the CBSR set can be improved.

[0159] In an example, the WTRU may first determine / select a CRI and / or PMI for TRP2 (e.g., based on configuration parameters and / or indications from the gNB). In response to determining the CRI and / or PMI for TRP2, the WTRU may (e.g., next) determine / select a second CRI and / or second PMI for TRP1, for example, based on the one or more CBSR sets and / or at least one of the one or more pairs of CSI-RS resources (e.g., for dynamically or semi-statically including / excluding PMI / CRI for TRP). In an example, the WTRU may determine which TRP's CRI and / or PMI, etc. is selected first (e.g., based on a dynamic selection by the gNB or a selection directed by the WTRU). The WTRU may indicate / report (e.g., be configured to indicate / report) which TRP is the primary TRP (e.g., by an explicit indicator or implicitly indicated / reported by the ordering of the PMIs in the report). This may provide the benefit that the WTRU may determine (eg, be configured to determine) to dynamically change the anchor (eg, link, reference) between the primary TRP and the secondary TRP.

[0160] In an example, the lookup table may be preconfigured or predefined to, for example, indicate an association between a PMI or PMI group of a first TRP or a first CSI-RS resource and a CBSR set of a second TRP or a second CSI-RS resource. TRP may be used interchangeably with CSI-RS resource, CSI-RS resource index, cell, physical cell id, measurement RS, and SSB. PMI may be used interchangeably with CSI-RS resource index (CRI), CQI, rank, strongest layer indicator (SLI), beam index, source RS index, and SSB index. The first TRP may be a primary TRP for which a PMI may be determined, and the PMI for the first TRP may determine one or more CBSR sets for the remaining TRPs grouped with the first TRP. The primary TRP may be one or more of the following: a serving TRP, a serving cell, a TRP associated with a cell-defining SSB, a TRP associated with the highest link quality (e.g., L1-SINR, L1-RSRP), a TRP associated with a PDCCH search space in which the WTRU may receive DCI for scheduling PDSCH transmissions and / or PUSCH transmissions, a TRP associated with a CORESET with a specific coresetPoolId (e.g., coresetPoolId=0), a TRP associated with a CSI-RS resource with a maximum number of antenna ports, a TRP associated with CORSET#0, and / or a TRP indicated as the primary TRP from the gNB. A CBSR set may be configured or defined commonly for TRPs (e.g., all TRPs). A CBSR set may be configured or defined for each TRP (e.g., alternatively). The number of bits of one or more PMIs (e.g., PMIs for one or more TRPs) used for CSI reporting may be determined, for example, based on an index determined for a first PMI. (Eg., each) CBSR set may have a different number of precoders. Feedback overhead for one or more PMIs may be determined, for example, based on determining which CBSR sets are used for the remaining TRPs. Separate coding (e.g., channel coding, channel coding) may be used for the first PMI, and the remaining PMIs may be determined from the CBSR set associated with the first PMI.

[0161] Table 1 illustrates an example of association between a first PMI of a first TRP and a set of CBSRs for other TRPs grouped with the first TRP.

[0162]

[0163]

[0164] Table 1

[0165] The WTRU may determine one or more CSI reporting amounts for a first TRP, for example based on one or more CSI reporting amounts determined for a second TRP, wherein the first TRP and the second TRP may be grouped for CSI reporting. One or more of the following may apply.

[0166] The CSI reporting quantity may be one or more of the following (e.g., at least one of the following but not limited to the at least one): CQI, PMI, RI, SLI, and CRI. For example, if the WTRU determines an RI value (e.g., RI=2) for a first TRP (e.g., TRP#1), the WTRU may use the determined RI value for a second TRP (e.g., TRP#2).

[0167] A subset of CSI reporting amounts may be determined (e.g., determined collectively) for one or more TRPs grouped together for CSI reporting. The remaining CSI reporting amounts may be determined individually for each TRP in the group. The subset may be indicated, configured, and / or determined by a base station (e.g., a gNB). The subset may be determined based on the number of TRPs in the group. The subset may be determined based on one or more CSI reporting types (e.g., CSI reporting configuration information).

[0168] In an example, the WTRU may determine a set of CBSRs for a TRP, for example, based on the WTRU's geographic location. For example, a base station (e.g., a gNB) may configure the set of CBSRs for a (e.g., specific) geographic location of a TRP, for example, where the geographic location may be (e.g., at least) one of: GPS coordination, a region identification, proximity to a specific TRP, a location determined based on measurements of a positioning reference signal (PRS), and / or a measured quality of a reference signal.

[0169] The WTRU may receive CSI reporting configuration information, wherein the WTRU may be indicated to include constrained CSI. This may be indicated as a flag for turning on / off one of the CSI constraints (eg, as described herein).

[0170] A Type IICSI reporting structure for C-JT may be provided.

[0171] The WTRU may receive configuration information for reporting type IICSI for a TRP (e.g., a single TRP). The CSI reporting configuration information may indicate a reporting type codebookType=type2 or type2-r16. The WTRU may report a (e.g., one) set of CSI components for (e.g., one) associated channel measurement resource (CMR), for example, where the CMR may be a reference signal (e.g., CSI-RS) indicated in the CSI measurement setup, and one of the CSI-RS may be associated to one TCI state. The WTRU may expect (e.g., only one) CSI-RS resource to be configured in the resource set for channel measurement.

[0172] Enhancements to Type IICSI reporting configuration information and WTRU reporting may be provided. For example, these enhancements may enable the WTRU to report CSI components assuming C-JT transmissions from more than one TRP.

[0173] CSI reporting configuration information for mTRP C-JT CSI may be provided. In an example, the WTRU may receive configuration information for reporting type IICSI for mTRP C-JT. The WTRU may report a set of type IICSI components (e.g., more than one set of type IICSI components), for example, where each component may be associated to a TRP. The WTRU may determine to report mTRP CSI by an explicit or implicit indication in the CSI reporting settings.

[0174] For example, in implicit operation, the WTRU may receive a CSI reporting setup with RS resources configured for mTRP C-JT for channel measurement. The CSI reporting setup may be configured with one or more of: (e.g., more than one) RS resources in a set of resources for channel measurement (e.g., where each RS may be associated with a different TCI state or QCL type D indication); or configured with (e.g., at least one) RS associated with more than one TCI state. The WTRU may determine that such configuration information may implicitly correspond to a C-JT CSI reporting assumption. For example, a subset of ports (e.g., a first subset of ports) may be associated with (e.g., one) TCI (e.g., a first TCI), and another subset (e.g., a second subset of ports) may be associated with a different TCI (e.g., a second TCI).

[0175] For example, for explicit operation, the WTRU may receive a CSI reporting setup that may be configured for mTRP reporting as a (e.g., new) codebook type codebookType=type2-r18 or type2-mTRP-r18. The WTRU may receive a set of RSs (e.g., CMRs) and RS groups, for example, where each group corresponds to a TRP. The WTRU may receive a bitmap that may, for example, pair RSs from different groups together. The WTRU may receive an indication of a measurement assumption for each pair (e.g., sTRP, C-JT, or NC-JT). The pair may consist of multiple (e.g., at least two) RS groups. Assuming a transmission assumption from a TRP pair associated with the RS pair, the WTRU may report CSI.

[0176] The WTRU may receive configuration information indicating a C-JT pair and may report CSI for the indicated pair.

[0177] The WTRU may receive a set of TRP pairs for C-JT. A subset of pairs may be activated, for example, dynamically or semi-statically. The WTRU may receive pair activations via DCI or via signaling (e.g., such as MAC-CE signaling). The WTRU may measure CSI for these pairs (e.g., all pairs or only a subset of pairs that have been activated). The WTRU may determine to include CSI components only for the activated pairs.

[0178] The WTRU may (e.g., alternatively) receive a set of activated TRPs. The WTRU may include CSI components for pairs with activated TRPs (e.g., only for pairs with activated TRPs). For example, the WTRU may receive configuration information indicating pairs {TRP1-TRP2} and {TRP2-TRP3}, and the WTRU may receive an activation command for TRP1 and TRP2. The WTRU may determine to report (e.g., only report) CSI for TRP1-TRP2.

[0179] The activation command may be included in a signal (e.g., MAC-CE) where a TCI state or codepoint is activated / deactivated and / or where (e.g., each) TCI state / codepoint is associated to a TRP. The WTRU may determine that an active TRP is associated with an active TCI state / codepoint. A (e.g., one) TCI codepoint may be configured with multiple (e.g., two) TCI states.

[0180] For example, in the case / time of reporting CSI, the WTRU may omit the non-activated TRP in the pairing. For example, if the WTRU receives CSI reporting configuration information with a {TRP1-TRP2-TRP3} pair and activation for TRP1 and TRP2, the WTRU may omit TRP3 and may report CSI (e.g., assuming only the {TRP1-TRP2} pair).

[0181] The WTRU may select a C-JT pair and may report the index of the pair and the CSI for the selected pair.

[0182] The WTRU may (e.g., alternatively) select a subset of TRP pairs from a set of TRP pairs (e.g., the entire set of TRP pairs) or from a set of activated TRP pairs. For example, the WTRU may include CSI for a subset of pairs if the grant for the CSI report (e.g., UCI) does not include (e.g., has) sufficient resources to accommodate these pairs (e.g., all pairs). The WTRU may report CSI for the selected subset. The WTRU may indicate the selected subset of pairs, for example, by a bitmap in the CSI report (e.g., where the WTRU reports 1 if the activated pairs are included). The WTRU may order the CSI reports according to the order in the bitmap. The WTRU may determine the subset of pairs based on one or more of: signal quality measurements received by the WTRU (e.g., the WTRU may measure the RSRP for each TRP and the WTRU may determine to report CSI for pairs including a TRP having an RSRP above a threshold); synchronization status (e.g., the WTRU may receive an indication of which TRP pairs are in synchronization and the WTRU may report mTRP CSI for (e.g., only) TRP pairs that are in synchronization; alternatively, the WTRU may determine which pairs are in synchronization based on the delay between receiving RS from the TRP pairs).

[0183] The WTRU may receive configuration information for reporting the PMI per TRP and / or the CSI common between TRPs.

[0184] In an example, the WTRU may report (e.g., one) type 2 PMI per TRP. The WTRU may report an inter-TRP co-phasing factor between a pair of TRPs. The WTRU may report a co-phasing factor α, for example, so that the WTRU determines the optimal precoder P=[P1α*P2], where P1 and P2 may be per-TRP (e.g., single TRP) PMIs from a type II codebook, and α may be a co-phasing factor. P may be defined as a C-JT precoder. For example, the WTRU may receive configuration information for reporting mTRP type 2 CSI for TRP1 and TRP2 and a co-phasing factor for TRP1 and TRP2. The WTRU may receive configuration information and determine to report (e.g., one) PMI per TRP and an inter-TRP co-phasing factor between TRP1 and TRP2. The WTRU may report (e.g., one) CQI per TRP or (e.g., one) joint CQI that depends on the C-JT precoder P.

[0185] The WTRU may receive a reporting quantity setting, which may indicate, for example, that a co-phasing factor is included. For example, the WTRU may receive configuration information for a reporting quantity (e.g., a new reporting quantity) having a co-phasing factor between TRPs (e.g., reportQuantity set to coPhasing). If configured, the WTRU may report PMI for multiple (e.g., two) TRP pairs that depend on the reported co-phasing value. Co-phasing reporting may be turned on or off and indicated as part of the CSI reporting configuration information. In the case of an on flag, the WTRU may include co-phasing. In the case of an off flag, the WTRU may omit co-phasing.

[0186] The WTRU may receive an indication of the granularity of the common phase reporting. The granularity may be indicated (e.g., explicitly indicated) or determined (e.g., implicitly determined), for example, based on the granularity of other PMI parameters (e.g., in time or frequency). For example, the common phase may be reported at a granularity (e.g., the same granularity) as configured for the PMI, or the common phase may be configured independently per subband or wideband.

[0187] The WTRU may report the PMI at different granularities, e.g., depending on the number of pairs reported. For example, the WTRU may receive different sets of configuration information and may determine to use a first set of configuration information if the number of pairs is greater than a threshold, and may determine to use another (e.g., second) set of configuration information if the number of pairs is less than a threshold (e.g., wideband reporting if / when more than two pairs are reported and subband reporting if / when less than two pairs are reported).

[0188] The WTRU may receive CSI configuration information, which is used, for example, to report the aggregate PMI for a TRP (e.g., all TRPs).

[0189] The WTRU may report a C-JT PMI, for example, without a common phase parameter (e.g., an additional common phase parameter). The WTRU may receive CSI reporting configuration information, for example, where reportQuantity may be configured for C-JT (e.g., cjt-PMI). The WTRU may be instructed to report a (e.g., one) PMI for an aggregated channel associated with a pair of TRPs. For example, the WTRU may receive configuration information with a C-JT pair {TRP1-TRP2} and receive an indication to report the cjt-PMI. The WTRU may report a PMI for an aggregated channel [H1H2], for example, where H1 and H2 are channels for the WTRU to link to TRP1 and TRP2, respectively. The WTRU may indicate a PMI from a precoding codebook, for example, in the case of having Nt1+Nt2 antennas (e.g., where Nt1 and Nt2 are the number of antenna ports from RSs associated with TRP1 and TRP2, respectively). The WTRU may report a CQI that depends on the aggregated PMI.

[0190] The WTRU may receive an indication of a pair of RSs that may be paired together for aggregate PMI reporting. If the WTRU receives CSI reporting configuration information with a pair of CMRs, the WTRU may determine to aggregate the CMRs in the pair, for example, to determine an aggregate channel and report a PMI that depends on the aggregate channel. An RS (e.g., a single RS) may (e.g., alternatively) be sent, for example, where a subset of ports may be transmitted from TRP1 and the remaining ports may be transmitted from TRP2. The WTRU may determine that such RS may be used for aggregate channel reporting.

[0191] The WTRU may determine based on a flag whether to report an aggregate PMI or per-TRP PMI and / or report a common phase.

[0192] In an example, the WTRU may determine to switch between aggregated PMI reporting or per-TRP PMI reporting and common reporting, for example, based on a flag.The WTRU may receive a flag as part of the CSI reporting setup for switching between reporting modes.

[0193] The WTRU may indicate the assumptions used for C-JT reporting.

[0194] In an example, the WTRU may determine to report CSI for an mTRP (e.g., assuming different transmission assumptions). For example, a report may be configured with multiple (e.g., two) reporting modes. The WTRU may determine that (e.g., one) reporting mode is for C-JT and another (e.g., different) reporting mode is for NC-JT. The WTRU may calculate multiple (e.g., two) CSIs (e.g., one for each reporting mode) and may include the (e.g., two) CSIs in a (e.g., one) CSI report. The WTRU may explicitly indicate the reporting mode associated with each CSI, or may implicitly indicate the reporting mode based on the ordering of the CSIs (e.g., C-JT first, NC-JT second).

[0195] The WTRU may select CSI reporting based on, for example, the priority between C-JT and other hypotheses.

[0196] In an example, the WTRU may select a CSI report (e.g., a different CSI report) for inclusion in a CSI report, for example, based on a priority between a C-JT measurement and other hypotheses. For example, the WTRU may determine to include a C-JT with a common phase as having a higher priority than a single TRP CSI, or vice versa. The WTRU may determine the priority, for example, based on enhancing the CSI priority value with a priority index for the C-JT or based on the ordering of the CSI in the CSI report. For example, the WTRU may include a C-JT with a high priority and may discard CSI for other hypotheses if they do not fit in the grant for the CSI report.

[0197] If the WTRU determines CSI for more than one TRP pair, the WTRU may drop some pairs from the CSI report. The WTRU may receive an indication of a high priority TRP or TRP pair, or the WTRU may determine a high priority TRP or TRP pair (e.g., based on received signal quality measurement, anchor TRP index, serving cell ID, traffic type (eMBB vs. URLLC)).

[0198] For example, in the case / time when multiple pairs are configured, the WTRU may include (e.g., at least one) C-JT CSI in the CSI report. For example, in the case / time when multiple pairs are configured, the WTRU may include (e.g., at least one) single TRP CSI. The WTRU may receive configuration information indicating the number of pairs and the number of single TRP CSI to be reported. The WTRU may (e.g., alternatively) include (e.g., only) C-JT CSI in the report.

[0199] The WTRU may receive a UCI grant (e.g., a separate UCI grant) for (e.g., each) TRP. The WTRU may report per-TRP C-JT CSI components based on the corresponding grant. The WTRU may (e.g., alternatively) include the C-JT CSI components (e.g., all C-JT CSI components) in a CSI report (e.g., a single CSI report) and may transmit it to (e.g., one) TRP.

[0200] The WTRU may determine the CSI report content based on the RS group configuration with multiple CMRs from different TRPs.

[0201] Multiple (e.g., two) reference signal groups (RSGs) may be configured to support NC-JT. For example, RSG1 may be configured with CMRs from TRP1 and RSG2 may be configured with CMRs from TRP2. The WTRU may report sTRP assumptions for CMRs from RSG1 and RSG2 from TRP1 or TRP2 respectively and / or NC-JT assumptions for CMRs from different RSGs (e.g., NC-JT with CMR1 and CMR2) (e.g., report either one).

[0202] For N>2 TRPs, the WTRU may receive configuration information indicating (e.g., configured with) N RSGs, where (e.g., each) RSG is associated to a TRP and (e.g., only) contains CMRs associated to that (e.g., associated) TRP. A (e.g., single) TCI state may be configured per CMR or RSG, for example, where (e.g., each) TCI state corresponds to a TRP beam.

[0203] In an example (e.g., for N>2), the WTRU may receive configuration information indicating (e.g., configured with) CMRs from more than one TRP within (e.g., one) RSG. For example, the WTRU may receive configuration information indicating (e.g., one) RSG where CMR1 is from TRP1 and CMR2 is from TRP2. The WTRU may receive configuration information indicating (e.g., configured to) report CSI based on the number of CMRs in the RSG under the C-JT assumption. In this case, the WTRU may receive CMR1 and CMR2 and measure the CSI (e.g., assuming the C-JT assumption from TRP1 and TRP2). The WTRU may report (e.g., one) CSI for the C-JT assumption from TRP1 and TRP2. The WTRU may (e.g., alternatively) (e.g., additionally) report, for the RSG, an sTRP assumption for (e.g., each) TRP configured in the RSG (e.g., in this case, sTRP1 and sTRP2 assumptions).

[0204] The WTRU may determine the association between the RSG and the TRP, for example, based on signaling (e.g., MAC-CE). The WTRU may receive signaling (e.g., MAC-CE) indicating that the CMRs per RSG are to be reconfigured. The signaling (e.g., MAC-CE) may include an index of a new CMR forming the RSG (e.g., for RSG reconfiguration). The signaling (e.g., MAC-CE) may (e.g., alternatively) include activation / deactivation signaling (e.g., bit 0 or 1) associated with (e.g., each) CMR in the RSG. The WTRU may determine that the CMR with bit 1 is activated, and the WTRU may report C-JT CSI for the activated CMR.

[0205] The WTRU may determine CSI report content based on port groups, where a (eg, single) CMR has multiple port groups.

[0206] An RSG may be configured for C-JT, where (e.g., each) CMR in the RSG includes (e.g., consists of) CSI-RS resources, where different PGs are associated to different TRPs. For example, an RSG may be configured with CSI-RS resources having 16 ports and multiple (e.g., two) PGs corresponding to multiple (e.g., two) TRPs. PG 1 may be associated to TRP1 and PG 2 may be associated to TRP2. (Each) PG may include (e.g., contain) more than one port. PG 1 may include (e.g., contain) 8 ports, and PG 2 may include (e.g., contain) the other 8 ports of CSI-RS resources. The WTRU may report C-JT assumptions for (e.g., any) CMR measurements from RSs belonging to such an RSG.

[0207] The WTRU may use a codebook (e.g., a Type IICSI port selection codebook) to report W2 CSI. The WTRU may use a Type IICSI port selection codebook to select a TRP for pre-decoder determination through PG selection. For example, the WTRU may receive configuration information indicating (e.g., configured with) a 4-port CSI-RS resource with PG 1 (including (e.g., consisting of) ports 1 and 2 associated to TRP1 with TCI state 1) and PG 2 (including (e.g., consisting of) ports 3 and 4 associated to TRP2 with TCI state 2). The WTRU may receive a 4-port CSI-RS and measure channels on the 4 ports.

[0208] The WTRU may report W2 including (e.g., consisting of) a port (e.g., all ports) of the CSI-RS (e.g., vector [1,1,1,1]) and (e.g., one) CQI to signal the WTRU to determine CSI feedback assuming C-JT across all ports for TRP1 and TRP2. The network may receive W2 and determine to calculate the precoder on TRP1 and TRP2.

[0209] In an example, the WTRU may report W2 including (e.g., consisting of) a port subset (e.g., [1,0,1,0]) along with (e.g., one) CQI to signal the WTRU to determine CSI feedback based on C-JT of ports 1 and 3 across TRP1 and TRP2, respectively.

[0210] In an example (e.g., with respect to the case described herein), the WTRU may report sTRP assumptions for (e.g., multiple) TRPs by reporting (e.g., one) CQI per PG (e.g., [1,1,1,1] with two CQIs, where the WTRU calculates CQI1 with ports 1 and 2 and CQI2 with ports 3 and 4).

[0211] For the sTRP assumption from TRP1 (e.g., only from TRP1), the WTRU may report W2 including (e.g., consisting of) ports (e.g., [1,0,0,0]) from the (e.g., single) TRP and (e.g., one) CQI.

[0212] The WTRU may receive configuration information indicating (e.g., configured with) priorities for (e.g., different) PGs (e.g., different priorities for each PG). For example, if (e.g., some, such as a number below or above a threshold) components of the CSI are omitted (e.g., the uplink grant for the CSI report has insufficient resources to fit all PGs), the WTRU may omit type IICSI from the CSI report (e.g., based on the priorities of different PGs). For example, the WTRU may calculate CSI for PG 1 and PG 2, and PG 1 may be determined to have a higher priority (e.g., than PG 2). The WTRU may include CSI for PG 1 (e.g., include CSI only for PG 1) in the CSI report (e.g., based on determining that PG 1 has a higher priority).

[0213] The priorities of (e.g., different) PGs may be determined by the WTRU. For example, the priorities may be determined based on the received signal power (e.g., RSRP) associated with the (e.g., two) TRPs. The WTRU may prioritize the highest signal power. For example, the priorities may be determined based on a (e.g., pre-configured) priority equation or a ranking based on PG / TRP. For example, PG 1 may be determined to have a higher priority than PG 2.

[0214] A WTRU (e.g., having multiple RSGs) may receive configuration information indicating an association between one or more RSGs and a codebook component (e.g., such as a base matrix). The WTRU may determine to use the (e.g., same) codebook component (e.g., spatial or frequency basis) for the one or more TRPs associated to the RSG to calculate and report CSI. With a (e.g., one) RS having multiple PGs, the WTRU may receive an association between one or more ports / PGs / TCI states and a codebook component (e.g., spatial or frequency basis). The WTRU may determine to use the (e.g., same) codebook component (e.g., spatial or frequency basis) for the one or more ports / PGs / TCI states in a (e.g., one) RS to calculate and report CSI. For example, the WTRU may receive configuration information indicating (e.g., configured with) a (e.g., one) CSI-RS with 4 ports (e.g., where ports 1 and 2 may be configured with PG1 for TRP1, and ports 3 and 4 may be configured with PG2 for TRP2). The WTRU may receive configuration information indicating TCI states 1 and 2 for TRPs 1 and 2, respectively. The WTRU may receive an indication indicating an association between ports 1, 2, 3, and 4 to calculate type IICSI, for example, using a spatial base matrix B1 (e.g., if TCI states 1 and 2 are indicated / configured). The WTRU may use the (e.g., same) spatial matrix B1 (e.g., a shared spatial matrix) to calculate type IICSI for (e.g., two) different PGs. The WTRU may receive an indication indicating an association between ports 1, 2, 3, and 4 to calculate type IICSI, for example, using a base matrix B2 (e.g., if the TCI state is changed to TCI 1 and 3 for TRP1 and TRP3).

[0215] Although the above features and elements are described in particular combinations, each feature or element may be used alone without the other features and elements of the preferred embodiments, or in various combinations with or without the other features and elements.

[0216] Although the implementations described herein may consider 3GPP specific protocols, it should be understood that the implementations described herein are not limited to such scenarios and may be applicable to other wireless systems. For example, although the solutions described herein consider LTE, LTE-A, New Radio (NR) or 5G specific protocols, it should be understood that the solutions described herein are not limited to such scenarios and may be applicable to other wireless systems.

[0217] The processes described above may be implemented in a computer program, software, and / or firmware incorporated in a computer-readable medium for execution by a computer and / or a processor. Examples of computer-readable media include, but are not limited to, electronic signals (sent via a wired or wireless connection) and / or computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, read-only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media (such as, but not limited to, built-in hard disks and removable disks), magneto-optical media, and optical media (such as compact disk (CD)-ROM disks and / or digital versatile disks (DVDs)). A processor associated with the software may be used to implement a radio frequency transceiver for a WTRU, a terminal, a base station, an RNC, and / or any host computer.

Claims

1. A wireless transmit / receive unit (WTRU), the wireless transmit / receive unit (WTRU) comprising: A processor, the processor being configured to: Receiving channel state information (CSI) report configuration information, wherein the CSI report configuration information indicates a codebook index (CI) set and a plurality of transmit / receive points (TRPs); determining first precoder matrix index (PMI) information for a first subset of TRPs from the plurality of TRPs and second PMI information for a second subset of TRPs from the plurality of TRPs; selecting a first subset of the TRPs based on the PMI information; determining at least two TRPs in the first subset of said TRPs as a base share, wherein determining the at least two TRPs in the first subset of TRPs as the basis for sharing is based on the CSI report configuration information; as well as transmitting a CSI report associated with a first subset of the TRPs based on at least determining the at least two TRPs in the first subset of the TRPs based on sharing, wherein the CSI report indicates a first subset of the TRP and first PMI information, And wherein the first PMI information includes a shared CI for the at least two TRPs that are basically shared in the first subset of the TRPs.

2. The WTRU according to claim 1, wherein if the at least two TRPs in the first subset of the TRPs are shared on a spatial domain (SD) basis, the shared CI includes a first shared CI, and wherein if the at least two TRPs in the first subset of the TRPs are shared on a frequency domain (FD) basis, the shared CI includes a second shared CI.

3. The WTRU according to claim 2, wherein the CI set includes a spatial domain (SD) CI set and a frequency domain (FD) CI set, and wherein the CSI report configuration information further indicates the number of columns in the SD matrix for each of the multiple TRPs and indicates the number of columns in the FD matrix for each of the multiple TRPs, wherein each SD CI in the SD CI set indicates a corresponding subset of columns in the SD matrix, and wherein each FD CI in the FD CI set indicates a corresponding subset of columns in the FD matrix.

4. The WTRU of claim 1 , wherein the processor is further configured to: A first measurement associated with a first subset of the TRPs and a second measurement associated with a second subset of the TRPs are performed, wherein the first PMI information is determined based on the first measurement and the second PMI information is determined based on the second measurement.

5. The WTRU according to claim 1, wherein the CSI report configuration information further indicates a first subset of the TRP and a second subset of the TRP, wherein the CSI report configuration information includes a TRP basic sharing indication, and wherein the TRP basic sharing indication indicates basic sharing information associated with the multiple TRPs.

6. The WTRU of claim 1, wherein the processor is further configured to determine a first subset of the TRPs and a second subset of the TRPs from the plurality of TRPs.

7. The WTRU of claim 1, wherein the first PMI information comprises a first channel quality indicator (CQI) value, wherein the second PMI information comprises a second CQI value, and wherein the first CQI value is higher than the second CQI value.

8. A WTRU according to claim 1, wherein the first PMI information includes a CI for each TRP in the first subset of the TRPs that is not a base shared TRP.

9. The WTRU of claim 2, wherein: If the at least two TRPs in the first subset of the TRPs are shared on a spatial domain (SD) basis, transmitting one SD CI for the at least two TRPs, wherein the first shared CI includes the one SD CI, and If the at least two TRPs in the first subset of the TRPs are shared on a frequency domain (FD) basis, one FD CI is transmitted for the at least two TRPs, wherein the second shared CI includes the one FD CI.

10. A method comprising: Receiving channel state information (CSI) report configuration information, wherein the CSI report configuration information indicates a codebook index (CI) set and a plurality of transmit / receive points (TRPs); determining first precoder matrix index (PMI) information for a first subset of TRPs from the plurality of TRPs and second PMI information for a second subset of TRPs from the plurality of TRPs; selecting a first subset of the TRPs based on the PMI information; Determining at least two TRPs in a first subset of the TRPs as a basis for sharing, wherein determining the at least two TRPs in the first subset of the TRPs as a basis for sharing is based on the CSI report configuration information; as well as A CSI report associated with a first subset of TRPs is transmitted based at least on determining that the at least two TRPs in the first subset of TRPs are shared on a basic basis, wherein the CSI report indicates the first subset of TRPs and the first PMI information, and wherein the first PMI information includes a shared CI for the at least two TRPs shared on a basic basis in the first subset of TRPs.

11. The method according to claim 10, wherein if the at least two TRPs in the first subset of the TRPs are shared on a spatial domain (SD) basis, the shared CI includes a first shared CI, and wherein if the at least two TRPs in the first subset of the TRPs are shared on a frequency domain (FD) basis, the shared CI includes a second shared CI.

12. The method of claim 11, wherein the CI set comprises a spatial domain (SD) CI set and a frequency domain (FD) CI set, and wherein the CSI report configuration information further indicates the number of columns in the SD matrix for each of the multiple TRPs and indicates the number of columns in the FD matrix for each of the multiple TRPs, wherein each SD CI in the SD CI set indicates a corresponding subset of columns in the SD matrix, and wherein each FDCI in the FD CI set indicates a corresponding subset of columns in the FD matrix.

13. The method according to claim 10, wherein the method further comprises: A first measurement associated with a first subset of the TRPs and a second measurement associated with a second subset of the TRPs are performed, wherein the first PMI information is determined based on the first measurement and the second PMI information is determined based on the second measurement.

14. The method according to claim 10, wherein the CSI report configuration information further indicates a first subset of the TRP and a second subset of the TRP, wherein the CSI report configuration information includes a TRP basic sharing indication, and wherein the TRP basic sharing indication indicates basic sharing information associated with the multiple TRPs.

15. The method according to claim 10, wherein the method further comprises: A first subset of the TRPs and a second subset of the TRPs are determined from the plurality of TRPs.

16. The method of claim 10, wherein the first PMI information comprises a first channel quality indicator (CQI) value, wherein the second PMI information comprises a second CQI value, and wherein the first CQI value is higher than the second CQI value.

17. The method of claim 10, wherein the first PMI information includes a CI for each TRP in the first subset of TRPs that is not a base shared TRP.

18. The method of claim 11, wherein: If the at least two TRPs in the first subset of the TRPs are shared on a spatial domain (SD) basis, transmitting one SD CI for the at least two TRPs, wherein the first shared CI includes the one SD CI, and If the at least two TRPs in the first subset of the TRPs are shared on a frequency domain (FD) basis, one FD CI is transmitted for the at least two TRPs, wherein the second shared CI includes the one FD CI.

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