Methods for PMI, ri and port indexing of CSI for multiple transmitter-receiver points

Abstract

To provide a method for wireless communications by user equipment (UE) for channel state information (CSI) reporting in multiple transmitter-receiver point (mTRP) scenarios.SOLUTION: In the method, the UE performs the steps of: determining a transmission scheme for CSI reporting using at least first and second CSI reference signal (CSI-RS) resources or port groups; performing CSI measurement based on CSI-RS transmissions sent via at least first and second CSI-RS resources or port groups; and transmitting, to a network entity, a precoding matrix indicator (PMI) report indicating a first set of one or more PMIs associated with the first resource or port-group, a second set of one or more PMIs associated with the second resource or port-group, a first layer indicator (LI) associated with the first set of PMIs, and a second LI associated with the second set of PMIs.SELECTED DRAWING: Figure 13

Description

Technical Field

[0001]

[0001] Aspects of the present disclosure relate to wireless communication, and more particularly, to techniques for determining channel state information for a plurality of transmitter receiver points that utilize different frequency domain resources.

Background Art

[0002]

[0002] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, broadcast, etc. These wireless communication systems may employ a multiple access technology capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmission power, etc.). Examples of such multiple access systems include, among others, the 3rd Generation Partnership Project (3GPP (registered trademark)) Long Term Evolution (LTE (registered trademark)) system, the LTE-Advanced (LTE-A) system, the Code Division Multiple Access (CDMA) system, the Time Division Multiple Access (TDMA) system, the Frequency Division Multiple Access (FDMA) system, the Orthogonal Frequency Division Multiple Access (OFDMA) system, the Single Carrier Frequency Division Multiple Access (SC-FDMA) system, and the Time Division Synchronous Code Division Multiple Access (TD-SCDMA) system.

[0003]

[0003] In some examples, a wireless multi-connectivity communication system may include several base stations (BSs) that are each capable of simultaneously supporting communication for a plurality of communication devices, sometimes known as user equipment (UE). In an LTE or LTE-A network, a set of one or more base stations may define an evolved Node B (eNB). In other examples (e.g., in a next-generation, New Radio (NR), or 5G network), a wireless multi-connectivity communication system may include several distributed units (DUs) (e.g., edge units (EUs), edge nodes (ENs), radio heads (RHs), smart radio heads (SRHs), transmission reception points (TRPs), etc.) communicating with several central units (CUs) (e.g., central nodes (CNs), access node controllers (ANCs), etc.), where a set of one or more DUs communicating with a CU may define an access node (sometimes referred to as, e.g., a BS, 5G NB, next-generation Node B (gNB or g-node B), transmission reception point (TRP), etc.). A BS or DU may communicate with a set of UEs on a downlink channel (e.g., for transmission from the BS or DU to the UE) and on an uplink channel (e.g., for transmission from the UE to the BS or DU).

[0004]

[0004] These multi-connectivity techniques are adopted in various telecommunications standards to provide a common protocol that enables different wireless devices to communicate at the urban, national, regional, and even global scale. NR (e.g., New Radio or 5G) is an example of a nascent telecommunications standard. NR is a set of extensions to the LTE mobile standard published by 3GPP. NR is designed to better support mobile broadband internet access by improving spectral efficiency, reducing costs, improving services, utilizing new spectrum, and better integrating with other open standards using Orthogonal Frequency Division Multiple Access (OFDMA) with a Cyclic Prefix (CP) on the downlink (DL) and uplink (UL). For these purposes, NR supports beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation.

[0005]

[0005] However, as the demand for mobile broadband access continues to increase, further improvements to NR and LTE technologies are needed. Preferably, these improvements should be applicable to other multi-connectivity techniques and the telecommunications standards that adopt these technologies.

Summary of the Invention

[0006]

[0006] The systems, methods, and devices of the present disclosure each have several aspects, and no single aspect among them necessarily bears the desirable attributes of the present disclosure alone. Here, several features are briefly described without limiting the scope of the present disclosure as represented by the following claims. After considering this description, and particularly after reading the section entitled "Detailed Description of the Invention," it will be understood how the features of the present disclosure provide advantages including improved communication between access points and stations in a wireless network.

[0007]

[0007] Some aspects provide a method for wireless communication by a user equipment (UE). The method generally includes receiving, from a network entity, a CSI report configuration indicating at least first and second CSI reference signal (CSI-RS) resources or port groups related to a channel state information (CSI) report; performing CSI measurements based on a frequency division multiplexing (FDM) scheme comprising transmission via a first resource or port-group on a first set of FD units and transmission via a second resource or port-group on a second set of FD units; and transmitting to the network entity a PMI report indicating a first set of one or more precoding matrix indicators (PMI) related to ports in the first resource or port-group on the first set of FD units and a second set of one or more PMI related to ports in the second resource or port-group on the second set of FD units.

[0008]

[0008] Some aspects provide a method for wireless communication by a network entity. The method generally includes transmitting, to a user equipment (UE), a CSI reporting configuration indicating at least first and second CSI reference signal (CSI-RS) resources or port groups related to channel state information (CSI) reporting; transmitting CSI-RS based on a frequency division multiplexing (FDM) scheme comprising transmission via a first resource or port group on a first set of FD units and transmission via a second resource or port group on a second set of FD units; and receiving, from the UE, a PMI report indicating a first set of one or more precoding matrix indicators (PMI) related to ports in a first resource or port group on a first set of FD units and a second set of one or more PMI related to ports in a second resource or port group on a second set of FD units.

[0009]

[0009] Some aspects provide a method for wireless communication by a user equipment (UE). The method generally includes determining a transmission scheme for CSI reporting using at least first and second channel state information (CSI) reference signal (CSI-RS) resources or port groups; performing CSI measurements based on CSI-RS transmissions sent via at least the first and second CSI-RS resources or port groups; and transmitting, to a network entity, a PMI report indicating a first set of one or more precoding matrix indicators (PMI) related to a first resource or port group, a second set of one or more PMI related to a second resource or port group, a first layer indicator (LI) related to the first set of PMI, and a second LI related to the second set of PMI.

[0010]

[0010] Some aspects provide a method for wireless communication by a network entity. The method generally includes transmitting, by a user equipment (UE), a channel state information (CSI) reference signal (CSI-RS) according to a transmission scheme using at least first and second CSI reference signal (RS) resource or port groups; and receiving, from the UE, a PMI report indicating a first set of one or more precoding matrix indicators (PMI) associated with the first resource or port group, a second set of one or more PMI associated with the second resource or port group, a first layer indicator (LI) associated with the first set of PMI, and a second LI associated with the second set of PMI.

[0011]

[0011] Some aspects provide a method for wireless communication by a user equipment (UE). The method generally includes receiving, from a network entity, a CSI report configuration, the configuration indicating at least one CSI-RS resource comprising at least first and second CSI reference signal (CSI-RS) port groups; determining a CSI codebook for each CSI-RS port associated with the PMI and channel quality indicator (CQI) measurements; and performing PMI and CQI measurements by using the determined CSI codebook, using the CSI-RS port index in each CSI-RS port group, and reporting a first PMI mapped to the port index in the first group and a second PMI mapped to the port index in the second group.

[0012]

[0012] Some aspects provide a method for wireless communication by a network entity. The method generally includes transmitting to a user equipment (UE) a CSI reporting configuration indicating at least one CSI-RS resource comprising at least first and second channel state information (CSI) reference signal (CSI-RS) port groups; determining a CSI codebook associated with each CSI-RS port for precoding matrix indicator (PMI) and channel quality indicator (CQI) measurements; and receiving from the UE a report of a first PMI mapped to a port index in a first group and a second PMI mapped to a port index in a second group based on PMI and CQI measurements performed by the UE using the CSI codebooks determined using the CSI-RS port indices in each of the CSI-RS port groups.

[0013]

[0013] Some aspects provide a means, apparatus, and / or computer-readable medium storing computer-executable code for performing the techniques described herein to process multi-TRP transmissions.

[0014]

[0014] To achieve the above and related objects, one or more aspects include the features that are fully described below and particularly pointed out in the claims. The following description and the accompanying drawings detail some exemplary features of one or more aspects. However, these features are only some of the many ways in which the principles of various aspects may be employed.

[0015]

[0015] To better understand the above-described features of the present disclosure, a more specific description, briefly summarized above, can be obtained by referring to the aspects shown in part in the drawings. However, it should be noted that since the description may lead to other equally valid aspects, the accompanying drawings show only some exemplary aspects of the present disclosure and should not be considered as limiting the scope of the present disclosure.

Brief Description of the Drawings

[0016]

Figure 1

[0016] Block diagram conceptually showing an exemplary telecommunications system according to some aspects of the present disclosure.

Figure 2

[0017] Block diagram showing an exemplary logical architecture of a distributed radio access network (RAN) according to some aspects of the present disclosure.

Figure 3

[0018] Diagram showing an exemplary physical architecture of a distributed RAN according to some aspects of the present disclosure.

Figure 4

[0019] Block diagram conceptually showing the design of an exemplary base station (BS) and user equipment (UE) according to some aspects of the present disclosure.

Figure 5

[0020] Diagram showing an exemplary frame and subframe according to some aspects of the present disclosure.

Figure 6

[0021] Diagram showing examples of single DCI and multi-DCI multi-TRP scenarios according to some aspects of the present disclosure.

Figure 7

Figure 8

[0022] Diagram showing an exemplary resource mapping for an mTRP scenario according to some aspects of the present disclosure.

Figure 9

[0023] Diagram showing examples of transport block (TB) determination, redundancy version (RV), and resource element (RE) mapping according to some aspects of the present disclosure.

Figure 10

[0024] Diagram showing an example of repetition within one slot according to some aspects of the present disclosure.

Figure 11

Figure 12

[0025] A diagram showing an exemplary mTRP CSI category according to some aspects of the present disclosure.

Figure 13

[0026] A diagram showing an exemplary operation for wireless communication by a user equipment (UE) according to some aspects of the present disclosure.

Figure 14

[0027] A diagram showing an exemplary operation for wireless communication by a network entity according to some aspects of the present disclosure.

Figure 15

[0028] A diagram showing an example of PMI reporting for the FDM method according to some aspects of the present disclosure.

Figure 16

[0029] A diagram showing an exemplary operation for wireless communication by a user equipment (UE) according to some aspects of the present disclosure.

Figure 17

[0030] A diagram showing an exemplary operation for wireless communication by a network entity according to some aspects of the present disclosure.

Figure 18

[0031] A diagram showing an exemplary operation for wireless communication by a user equipment (UE) according to some aspects of the present disclosure.

Figure 19

[0032] A diagram showing an exemplary operation for wireless communication by a network entity according to some aspects of the present disclosure.

Figure 20A

[0033] A diagram showing an example of PMI and CQI measurements using CSI-RS port indexing according to some aspects of the present disclosure.

Figure 20B

Figure 20C

Figure 21

[0034] A diagram showing an exemplary component capable of performing operations according to some aspects of the present disclosure.

Mode for Carrying Out the Invention

[0017]

[0035] For ease of understanding, the same reference numbers are used to designate the same elements common to each figure, where possible. It is contemplated that elements disclosed in one aspect can be beneficially utilized with respect to other aspects without particular recitation.

[0018]

[0036] Aspects of the present disclosure relate to techniques for wireless communication, and more particularly, to techniques for reporting channel state information (CSI) such as precoding matrix indicator (PMI) and layer indicator (LI) in a multi-transmit receive point (mTRP) scenario.

[0019]

[0037] In some cases, the UE may perform mTRP CSI measurements based on a frequency division multiplexing (FDM) scheme comprising transmission via a first resource or port group on a first set of FD units and transmission via a second resource or port group on a second set of FD units. The UE may transmit a PMI report indicating a first set of one or more PMIs associated with ports in a first resource or port group on a first set of FD units and a second set of one or more PMIs associated with ports in a second resource or port group on a second set of FD units.

[0020]

[0038] In some cases, the UE may perform mTRP CSI measurements based on CSI-RS transmissions sent via at least a first and a second CSI-RS resource or port group. The UE may transmit a PMI report indicating a first set of one or more PMIs associated with the first resource or port group, a second set of one or more PMIs associated with the second resource or port group, a first layer indicator (LI) associated with the first set of PMIs, and a second LI associated with the second set of PMIs.

[0021]

[0039] In some cases, the UE may determine a CSI codebook associated with each CSI-RS port for PMI and channel quality indicator (CQI) measurements. The UE may use the determined CSI codebook and the CSI-RS port indexes in each CSI-RS port group to perform PMI and CQI measurements by reporting a first PMI mapped to the port index in the first group and a second PMI mapped to the port index in the second group.

[0022]

[0040] The following description provides examples and is not intended to limit the scope, applicability, or examples described in the claims. Without departing from the scope of the present disclosure, changes can be made to the functions and configurations of the elements discussed. Various examples can omit, substitute, or add various procedures or components as appropriate. For example, the methods described can be performed in an order different from the order described, and various steps can be added, omitted, or combined. Also, the features described for some examples can be combined in some other examples. For example, the apparatus can be implemented or the method can be performed using any number of the aspects described herein. Further, the scope of the present disclosure is intended to cover such apparatus or methods implemented using other structures, functions, or structures and functions in addition to, or other than, the various aspects of the present disclosure described herein. It should be understood that any aspect of the present disclosure disclosed herein can be implemented by one or more elements of the claims. The word "exemplary" is used herein to mean "an example, instance, or serving as an illustration." Any aspect described herein as "exemplary" should not necessarily be construed as preferred or advantageous over other aspects.

[0023]

[0041] The techniques described herein can be used for various wireless communication technologies such as LTE, CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and other networks. The terms "network" and "system" are often used interchangeably. A CDMA network may implement radio technologies such as Universal Terrestrial Radio Access (UTRA), cdma2000, etc. UTRA includes Wideband CDMA (WCDMA (registered trademark)) and other variants of CDMA. Cdma2000 encompasses the IS-2000, IS-95, and IS-856 standards. A TDMA network may implement radio technologies such as Global System for Mobile Communications (GSM (registered trademark)). An OFDMA network may implement radio technologies such as NR (e.g., 5G RA), Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE802.11 (Wi-Fi (registered trademark)), IEEE802.16 (WiMAX (registered trademark)), IEEE802.20, Flash-OFDMA, etc. UTRA and E-UTRA are part of the Universal Mobile Telecommunications System (UMTS).

[0024]

[0042] New Radio (NR) is a nascent wireless communication technology being developed together with the 5G Technology Forum (5GTF). 3GPP Long Term Evolution (LTE) and LTE Advanced (LTE-A) are releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, and GSM are described in documents from a group called the "3rd Generation Partnership Project" (3GPP), and cdma2000 and UMB are described in documents from a group called the "3rd Generation Partnership Project 2" (3GPP2). The techniques described herein may be used for the wireless networks and radio technologies above, as well as other wireless networks and radio technologies. For clarity, although aspects may be described herein using terms commonly associated with 3G and / or 4G wireless technologies, aspects of the present disclosure may be applied in other generation-based communication systems such as, but not limited to, 5G and later, including NR technology.

[0025]

[0043] New Radio (NR) access (e.g., 5G technology) supports various wireless communication services such as extended mobile broadband (eMBB) targeting wide bandwidth (e.g., 80 MHz or more), millimeter wave (mmW) targeting high carrier frequencies (e.g., 25 GHz or more), massive machine type communication MTC (mMTC) targeting non-backward compatible MTC techniques, and / or mission critical targeting ultra-reliable low-latency communication (URLLC). These services may include latency and reliability requirements. These services may also have different transmission time intervals (TTIs) in order to meet their respective quality of service (QoS) requirements. Further, these services may coexist within the same subframe.

[0026] Exemplary Wireless Communication System

[0044] FIG. 1 shows an exemplary wireless communication network 100 in which aspects of the present disclosure may be implemented. For example, network 100 may include one or more UEs 120 configured to perform operations 1300 of FIG. 13, operations 1600 of FIG. 16, and / or operations 1800 of FIG. 18 to measure and report mTRP CSI. Similarly, network 100 may include one or more base stations (BSs) 110 configured to receive and process the mTRP CSI reported by UEs 120 (performing operations 1300 of FIG. 13, operations 1600 of FIG. 16, and / or operations 1800 of FIG. 18) by performing operations 1400 of FIG. 14, operations 1700 of FIG. 17, and / or operations 1900 of FIG. 19.

[0027]

[0045] As shown in FIG. 1, wireless communication network 100 may include several base stations (BSs) 110 and other network entities. A BS may be a station that communicates with user equipment (UE). Each BS 110 may provide communication coverage for a particular geographic area. In 3GPP, the term “cell” may refer to the coverage area of a Node B (NB) and / or the NB subsystem serving this coverage area, depending on the context in which the term is used. In an NR system, the terms “cell” and next-generation Node B (gNB or g-node B), NR BS, 5G NB, access point (AP), or transmission and reception point (TRP) may be interchangeable. In some examples, a cell may not necessarily be fixed, and the geographic area of a cell may move according to the location of a mobile BS. In some examples, base stations may be interconnected with each other and / or with one or more other base stations or network nodes (not shown) in wireless communication network 100 through various types of backhaul interfaces, such as direct physical connections, wireless connections, virtual networks, etc., using any suitable transport network.

[0028]

[0046] Generally, any number of wireless networks can be deployed in a given geographical area. Each wireless network may support a specific radio access technology (RAT) and may operate on one or more frequencies. RAT may also be referred to as wireless technology, air interface, etc. Frequencies may also be referred to as carriers, subcarriers, frequency channels, tones, subbands, etc. Each frequency may support a single RAT in a given geographical area to avoid interference between wireless networks of different RATs. In some cases, an NR or 5G RAT network may be deployed.

[0029]

[0047] A BS may provide communication coverage to macrocells, picocells, femtocells, and / or other types of cells. A macrocell may cover a relatively large geographical area (e.g., several kilometers in radius) and may enable unrestricted access by UEs subscribed to the service. A picocell may cover a relatively small geographical area and may enable unrestricted access by UEs subscribed to the service. A femtocell may cover a relatively small geographical area (e.g., a home) and may enable restricted access by UEs associated with the femtocell (e.g., UEs in a closed subscriber group (CSG), UEs for users within the home, etc.). The BS for a macrocell may sometimes be called a macro BS. The BS for a picocell may sometimes be called a pico BS. The BS for a femtocell may sometimes be called a femto BS or a home BS. In the example shown in FIG. 1, BS110a, 110b, and 110c may each be a macro BS for macrocells 102a, 102b, and 102c, respectively. BS110x may be a pico BS for picocell 102x. BS110y and 110z may each be a femto BS for femtocells 102y and 102z, respectively. A BS may support one or more (e.g., three) cells.

[0030]

[0048] Wireless communication network 100 may also include relay stations. A relay station is a station that receives the transmission of data and / or other information from an upstream station (e.g., a BS or a UE) and sends the transmission of the data and / or other information to a downstream station (e.g., a UE or a BS). A relay station may also be a UE that relays transmissions to other UEs. In the example shown in FIG. 1, relay station 110r may communicate with BS110a and UE120r to facilitate communication between BS110a and UE120r. Relay stations may also be referred to as relay BSs, relays, etc.

[0031]

[0049] Wireless communication network 100 may be a heterogeneous network including different types of BSs, such as macro BSs, pico BSs, femto BSs, relays, etc. These different types of BSs may have different transmission power levels, different coverage areas, and different impacts on interference in wireless communication network 100. For example, a macro BS may have a high transmission power level (e.g., 20 watts), while pico BSs, femto BSs, and relays may have a lower transmission power level (e.g., 1 watt).

[0032]

[0050] Wireless communication network 100 may support synchronous operation or asynchronous operation. In the case of synchronous operation, BSs may have similar frame timings, and transmissions from different BSs may be approximately time-aligned. In the case of asynchronous operation, BSs may have different frame timings, and transmissions from different BSs may not be time-aligned. The techniques described herein may be used for both synchronous operation and asynchronous operation.

[0033]

[0051] Network controller 130 may be coupled to a set of BSs and may coordinate and control these BSs. Network controller 130 may communicate with BS110 via a backhaul. BS110s may also communicate with each other (e.g., directly or indirectly) via a wireless backhaul or a wireline backhaul.

[0034]

[0052] UE 120 (e.g., 120x, 120y, etc.) can be distributed throughout the wireless communication network 100, and each UE can be fixed or mobile. A UE can be a mobile station, a terminal, an access terminal, a subscriber unit, a station, a customer premise equipment (CPE), a cellular phone, a smartphone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet computer, a camera, a gaming device, a netbook, a smartbook, an ultrabook, an appliance, a medical device or instrument, a biosensor / device, a smartwatch, a smart closing, a smart glass, a smart list band, a wearable device such as smart jewelry (e.g., a smart ring, a smart bracelet, etc.), an entertainment device (e.g., a music device, a video device, a satellite radio, etc.), a vehicle component or sensor, a smart meter / sensor, an industrial manufacturing device, a global positioning system device, or any other suitable device configured to communicate via a wireless or wired medium. Some UEs can be regarded as machine type communication (MTC) devices or evolved MTC (eMTC) devices. MTC UEs and eMTC UEs can communicate with, for example, a BS, another device (e.g., a remote device), or some other entity, including robots, drones, remote devices, sensors, meters, monitors, location tags, etc. A wireless node can provide a connection for a network (e.g., a wide area network such as the Internet or a cellular network) or to a network via, for example, a wired communication link or a wireless communication link. Some UEs can be regarded as Internet of Things (IoT) devices, such as narrowband IoT (NB-IoT) devices.

[0035]

[0053] Some wireless networks (e.g., LTE) utilize Orthogonal Frequency Division Multiplexing (OFDM) on the downlink and Single Carrier Frequency Division Multiplexing (SC-FDM) on the uplink. OFDM and SC-FDM divide the system bandwidth into multiple (K) orthogonal subcarriers, also commonly referred to as tones, bins, etc. Each subcarrier can be modulated with data. Generally, the modulated symbols are sent in the frequency domain for OFDM and in the time domain for SC-FDM. The spacing between adjacent subcarriers can be fixed, and the total number of subcarriers (K) can depend on the system bandwidth. For example, the subcarrier spacing can be 15 kHz, and the minimum resource allocation (referred to as a "resource block" (RB)) can be 12 subcarriers (or 180 kHz). Thus, the nominal Fast Fourier Transform (FFT) size can be equal to 128, 256, 512, 1024, or 2048 for system bandwidths of 1.25, 2.5, 5, 10, or 20 megahertz (MHz), respectively. The system bandwidth can also be divided into subbands. For example, a subband can cover 1.08 MHz (i.e., 6 resource blocks), and there can be 1, 2, 4, 8, or 16 subbands for system bandwidths of 1.25, 2.5, 5, 10, or 20 MHz, respectively.

[0036]

[0054] The example aspects described herein may relate to LTE technology, but aspects of the present disclosure may be applicable with other wireless communication systems such as NR. NR can utilize OFDM with a cyclic prefix (CP) on both the uplink and downlink and may include support for half-duplex operation using Time Division Duplexing (TDD). Beamforming may be supported, and the beam direction may be dynamically configured. MIMO transmission using precoding may also be supported. The MIMO configuration in the DL can support up to 8 transmit antennas using multi-layer DL transmission with up to 8 streams and up to 2 streams per UE. Multi-layer transmission using up to 2 streams per UE may be supported. Aggregation of multiple cells may be supported using up to 8 serving cells.

[0037]

[0055] In some examples, access to the air interface can be scheduled. A scheduling entity (e.g., a BS) allocates resources for communication between some or all of the devices and apparatuses within its service area or cell. The scheduling entity may be responsible for scheduling, allocating, reconfiguring, and releasing resources for one or more subordinate entities. That is, for scheduled communication, the subordinate entities utilize the resources allocated by the scheduling entity. The base station is not the only entity that can function as a scheduling entity. In some examples, a UE can function as a scheduling entity, can schedule resources for one or more subordinate entities (e.g., one or more other UEs), and other UEs can utilize the resources scheduled by the UE for wireless communication. In some examples, a UE can function as a scheduling entity in a peer-to-peer (P2P) network and / or in a mesh network. In a mesh network example, in addition to communicating with a scheduling entity, UEs can communicate directly with each other.

[0038]

[0056] In FIG. 1, the solid lines with double arrows indicate desired transmissions between a UE and a serving BS, which is the BS designated to serve that UE, on the downlink and / or uplink. The thin dashed lines with double arrows indicate interfering transmissions between the UE and the BS.

[0039]

[0057] Figure 2 shows an exemplary logical architecture of a distributed radio access network (RAN) 200 that can be implemented in the wireless communication network 100 shown in Figure 1. The 5G access node 206 can include an access node controller (ANC) 202. The ANC 202 can be a central unit (CU) of the distributed RAN 200. The backhaul interface to the next generation core network (NG-CN) 204 can terminate at the ANC 202. The backhaul interface to neighboring next generation access nodes (NG-ANs) 210 can terminate at the ANC 202. The ANC 202 can include one or more TRPs 208 (e.g., cells, BSs, gNBs, etc.).

[0040]

[0058] The TRP 208 can be a distributed unit (DU). The TRP 208 can be connected to a single ANC (e.g., ANC 202) or two or more ANCs (not shown). For example, in the case of RAN sharing, radio as a service (RaaS), and service-specific AND placement, the TRP 208 can be connected to two or more ANCs. Each TRP 208 can include one or more antenna ports. The TRP 208 can be configured to serve traffic to the UE individually (e.g., dynamic selection) or together (e.g., joint transmission).

[0041]

[0059] The logical architecture of the distributed RAN 200 can support fronthauling solutions across different deployment types. For example, the logical architecture can be based on transmission network capabilities (e.g., bandwidth, latency, and / or jitter).

[0042]

[0060] The logical architecture of the distributed RAN 200 can share features and / or components with LTE. For example, the next generation access node (NG-AN) 210 can support dual connectivity with NR and share a common fronthaul for LTE and NR.

[0043]

[0061] The logical architecture of the distributed RAN 200 can enable cooperation between TRPs 208, for example, within a TRP and / or across TRPs via the ANC 202. The inter-TRP interface may not be used.

[0044]

[0062] The logical functions can be dynamically distributed in the logical architecture of the distributed RAN 200. As will be described in more detail with reference to FIG. 5, the radio resource control (RRC) layer, the packet data convergence protocol (PDCP) layer, the radio link control (RLC) layer, the media access control (MAC) layer, and the physical (PHY) layer can be adaptively arranged in the DU (for example, the TRP 208) or the CU (for example, the ANC 202).

[0045]

[0063] FIG. 3 shows an exemplary physical architecture of a distributed RAN 300 according to an aspect of the present disclosure. The centralized core network unit (C-CU) 302 can host core network functions. The C-CU 302 can be deployed centrally. The functionality of the C-CU 302 can be offloaded (for example, to an advanced wireless service (AWS)) to handle peak capacity.

[0046]

[0064] The centralized RAN unit (C-RU) 304 can host one or more ANC functions. Optionally, the C-RU 304 can locally host core network functions. The C-RU 304 can have a distributed deployment. The C-RU 304 may be close to the network edge.

[0047]

[0065] The DU 306 can host one or more TRPs (edge nodes (EN), edge units (EU), radio heads (RH), smart radio heads (SRH), etc.). The DU can be located at the edge of the network with radio frequency (RF) functions.

[0048]

[0066] Figure 4 shows exemplary components of BS110 and UE120 (shown in FIG. 1) that may be used to implement aspects of the present disclosure. For example, antenna 452, processors 466, 458, 464, and / or controller / processor 480 of UE120 may perform (or may be used to perform) operation 1300 of FIG. 13, operation 1600 of FIG. 16, and / or operation 1800 of FIG. 18. Similarly, antenna 434, processors 420, 430, 438, and / or controller / processor 440 of BS110 may perform (or may be used to perform) operation 1400 of FIG. 14, operation 1700 of FIG. 17, and / or operation 1900 of FIG. 19.

[0049]

[0067] In BS110, the transmission processor 420 can receive data from the data source 412 and control information from the controller / processor 440. The control information can be for the physical broadcast channel (PBCH), physical control format indicator channel (PCFICH), physical hybrid ARQ indicator channel (PHICH), physical downlink control channel (PDCCH), group common PDCCH (GC PDCCH), etc. The data can be for the physical downlink shared channel (PDSCH). The processor 420 can process (e.g., encode and symbol map) the data and control information respectively to obtain data symbols and control symbols. The processor 420 can also generate reference symbols for, e.g., the primary synchronization signal (PSS), secondary synchronization signal (SSS), and cell-specific reference signal (CRS). The transmit (TX) multiple-input multiple-output (MIMO) processor 430 can perform spatial processing (e.g., precoding) on the data symbols, control symbols, and / or reference symbols when applicable, and provide the output symbol stream to the modulators (MOD) 432a - 432t. Each modulator 432 can process its respective output symbol stream (for, e.g., OFDM) to obtain an output sample stream. Each modulator can further process the output sample stream (e.g., convert to analog, amplify, filter, and up-convert) to obtain a downlink signal. The downlink signals from the modulators 432a - 432t can be transmitted via the antennas 434a - 434t respectively.

[0050]

[0068] In UE120, antennas 452a to 452r can receive a downlink signal from base station 110 and can provide the received signal to a demodulator (DEMOD) in each of transceivers 454a to 454r, respectively. Each demodulator 454 can condition (e.g., filter, amplify, down-convert, and digitize) the respective received signal to obtain input samples. Each demodulator can further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. MIMO detector 456 can obtain received symbols from all demodulators 454a to 454r, perform MIMO detection on the received symbols if applicable, and provide the detected symbols. Receiver processor 458 can process the detected symbols (e.g., demodulate, deinterleave, and decode), provide the decoded data for UE120 to data sink 460, and provide the decoded control information to controller / processor 480.

[0051]

[0069] On the uplink, at UE120, transmission processor 464 may receive and process data from data source 462 (e.g., for the physical uplink shared channel (PUSCH)) and may receive and process control information from controller / processor 480 (e.g., for the physical uplink control channel (PUCCH)). Transmission processor 464 may also generate reference symbols for reference signals (e.g., for the sounding reference signal (SRS)). Symbols from transmission processor 464 may be precoded by TX MIMO processor 466 when applicable and may be further processed by a demodulator in transceivers 454a - 454r (e.g., for SC - FDM) and transmitted to base station 110. At BS110, the uplink signal from UE120 is received by antenna 434, processed by modulator 432, detected by MIMO detector 436 when applicable, and may be further processed by receive processor 438 to obtain the decoded data and control information sent by UE120. Receive processor 438 may provide the decoded data to data sink 439 and may provide the decoded control information to controller / processor 440.

[0052]

[0070] Controllers / processors 440 and 480 may each direct operations at BS110 and UE120, respectively. Processor 440 and / or other processors and modules at BS110 may perform or direct the execution of processes for the techniques described herein. Memories 442 and 482 may each store data and program code for BS110 and UE120, respectively. Scheduler 444 may schedule UEs for data transmission on the downlink and / or uplink.

[0053]

[0071] In LTE, the basic transmission time interval (TTI) or packet duration is a 1 ms subframe. In NR, although the subframe is still 1 ms, the basic TTI is called a slot. The subframe contains a variable number of slots (e.g., 1, 2, 4, 8, 16,... slots) depending on the subcarrier spacing. An NR RB is 12 consecutive frequency subcarriers. NR can support a base subcarrier spacing of 15 kHz, and other subcarrier spacings can be defined relative to the base subcarrier spacing, such as 30 kHz, 60 kHz, 120 kHz, 240 kHz, etc. The symbol and slot lengths scale with the subcarrier spacing. The CP length also depends on the subcarrier spacing.

[0054]

[0072] FIG. 5 is a diagram showing an example of a frame format 500 for NR. The transmission time lines for each of the downlink and uplink can be divided into units of radio frames. Each radio frame can have a predetermined duration (e.g., 10 ms) and can be divided into 10 subframes, each of 1 ms, with indices from 0 to 9. Each subframe can include a variable number of slots depending on the subcarrier spacing. Each slot can include a variable number of symbol periods (e.g., 7 or 14 symbols) depending on the subcarrier spacing. The symbol periods within each slot can be assigned indices. A mini-slot, sometimes called a sub-slot structure, refers to a transmission time interval having a duration smaller than a slot (e.g., 2, 3, or 4 symbols).

[0055]

[0073] Each symbol in a slot can indicate a link direction (e.g., DL, UL, or flexible) for data transmission, and the link direction for each subframe can be dynamically switched. The link direction can be based on the slot format. Each slot can include DL / UL data and DL / UL control information.

[0056]

[0074] In NR, a Synchronization Signal (SS) block is transmitted. The SS block includes a Primary Synchronization Signal (PSS), a Secondary Synchronization Signal (SSS), and a 2-symbol Physical Broadcast Channel (PBCH). The SS block can be transmitted at a fixed slot location, such as symbols 0 to -3, as shown in FIG. 5. The PSS and SSS can be used by the UE for cell search and acquisition. The PSS can provide half-frame timing, and the SSS can provide cyclic prefix (CP) length and frame timing. The PSS and SSS can provide cell identification information. The PBCH carries several basic system information, such as downlink system bandwidth, timing information within a radio frame, SS burst set periodicity, and system frame number. The SS block can be grouped into SS bursts to support beam sweeping. Further system information, such as Remaining Minimum System Information (RMSI), System Information Block (SIB), and Other System Information (OSI), can be transmitted on the Physical Downlink Shared Channel (PDSCH) in several subframes. The SS block can be transmitted up to 64 times, for example, up to 64 different beam directions for mmWave. The up to 64 transmissions of the SS block are called an SS burst set. The SS blocks in an SS burst set are transmitted in the same frequency region, and the SS blocks in different SS burst sets can be transmitted at different frequency locations.

[0057]

[0075] In some situations, two or more subordinate entities (e.g., UEs) may communicate with each other using sidelink signals. Examples of real-world applications of such sidelink communication may include public safety, proximity services, UE-to-network relaying, vehicle-to-vehicle (V2V) communication, Internet of Everything (IoE) communication, IoT communication, mission-critical mesh, and / or various other suitable applications. Generally, sidelink signals can be utilized by a scheduling entity (e.g., a UE or a BS) for scheduling and / or control purposes, but may refer to signals communicated from one subordinate entity (e.g., UE1) to another subordinate entity (e.g., UE2) without relaying that communication through the scheduling entity. In some examples, sidelink signals may be communicated using licensed spectrum (as opposed to wireless local area networks that generally use unlicensed spectrum).

[0058]

[0076] The UE can operate in various radio resource configurations, including configurations related to transmitting pilots using a dedicated set of resources (e.g., Radio Resource Control (RRC) dedicated state, etc.) or configurations related to transmitting pilots using a common set of resources (e.g., RRC common state, etc.). When operating in the RRC dedicated state, the UE can select a dedicated set of resources for transmitting pilot signals to the network. When operating in the RRC common state, the UE can select a common set of resources for transmitting pilot signals to the network. In either case, the pilot signal transmitted by the UE can be received by one or more network access devices, such as the AN, or the DU, or parts thereof. Each receiving network access device is configured to receive and measure the pilot signal transmitted on the common set of resources, and also to receive and measure the pilot signal transmitted on the dedicated set of resources allocated to the UE for which the network access device is a member of the monitoring set of network access devices for the UE. One or more of the receiving network access devices, or the CU to which the (one or more) receiving network access devices transmit the measurement values of the pilot signal, can use the measurement values to identify the serving cell for the UE or to initiate a change of the serving cell for one or more of the UEs.

[0059] Exemplary multi-TRP scenario

[0077] In 3GPP New Radio (NR) Release 16 (R16), multi-TRP operation was introduced to increase system capacity and reliability. FIGS. 6 and 7 show exemplary scenarios of multi-TRP operation in which aspects of the present disclosure can be implemented.

[0060]

[0078] As shown in FIG. 6, in some examples, multi-TRP transmission may be configured based on a single downlink control information (DCI). (For example, transmitted from the first TRP (TRP1) via PDCCH) A single DCI schedules a physical downlink shared channel (PDSCH) from TRP1 and a PDSCH from a second TRP (TRP2).

[0061]

[0079] Multi-TRP operation configured based on single DCI communication may be best suited for deployment in an ideal backhaul or a backhaul with small latency and may involve various transmission schemes. The transmission scheme may include, for example, a spatial division multiplexing (SDM) scheme, a frequency division multiplexing (FDM), or a time division multiplexing (TDM).

[0062]

[0080] In SDM, also known as non-coherent joint transmission (NCJT), a first set of layers is transmitted from TRP1 and a second set of layers is transmitted from TRP2. Transmission may utilize the same frequency domain resource allocation (FDRA) and time division resource allocation (TDRA). In FDM, transmissions from two TRPs may have the same rank and the same codeword (CW), but have different FDRAs across the two TRPs. In TDM, transmissions from two TRPs may have the same rank and the same CW, but have different TDRAs across the two TRPs.

[0063]

[0081] In some cases, the PDSCH may be sent in multiple parts. For example, TRP1 may send a first part (on the first set of layers using the first set of FDRA and the first set of TDRA), and TRP2 may send a second part (on the second set of layers using the second set of FDRA and the second set of TDRA).

[0064]

[0082] As shown in FIG. 7, in some examples, multi-TRP transmission may be configured based on multiple DCIs. In the case of multi-DCI, each DCI schedules an individual PDSCH (similar to the CA framework). For example, the first DCI from TRP1 (transmitted, for example, in PDCCH1) schedules PDSCH1 from TRP1, and the second DCI (transmitted, for example, in PDCCH2) schedules PDSCH2 from TRP2. The two scheduled PDSCHs may overlap, not overlap, or partially overlap in the frequency domain or the time domain.

[0065]

[0083] FIG. 8 shows an exemplary resource mapping for mTRP deployment using the FDM method. As shown, two TRPs may occupy different sets of RBs (from a common FDRA) with their respective TCI states (TCI1 for TRP1 and TCI2 for TRP2). The FDRA field in the DCI may indicate the RB allocation for both TCI states. As shown, for a wideband physical resource block group (PRG), the RBs are allocated to TCI state 1 in the first half and to TCI state 2 in the second half. For a narrowband PRG (equal to two RBs or four RBs), even-numbered PRGs may be allocated to TCI state 1 and odd-numbered PRGs may be allocated to TCI state 2.

[0066]

[0084] FIG. 9 shows examples of different methods for mapping from CW to layers according to some aspects of the present disclosure. According to the first method (method 2A), there may be one CW and one RV mapped to the resource in the order of layer, frequency domain, and time domain. According to the second method (method 2b), the same TB may be sent using different RVs. For example, the TB may be transmitted using the first RV in RB set 1 (TRP1), while in RB set 2 (TRP2), it may be transmitted using the second RV.

[0067]

[0085] Figures 10 and 11 show examples of the TDM method for repetition by different transmission methods. According to the first method (method 3 shown in Figure 10), in the repetition within one slot, when two TCIs are shown, the two TRPs can perform TDM transmission using repetitions with different RVs. In some cases, the gap can be located between the first transmission opportunity with TCI state 1 and the second transmission opportunity with TCI state 2. In some cases, this gap can be configured (e.g., via a network). The lengths of the first transmission opportunity and the second transmission opportunity are the same. In Figure 10, the first transmission is composed of a start symbol index S = 3 and a length L = 4 as indicated by the TDRA field. The second transmission opportunity can have a TCI state 2 with the same length L = 4 as the first transmission opportunity. In this case, the gap is two symbols.

[0068]

[0086] According to another method (single frequency network, SFN), the PDSCH transmitted from each TRP shares the same FDRA and TDRA, and the same layer of the same codeword is transmitted. In this case, each layer can be transmitted from two TRPs, and each DMRS port can be associated with two different TCI states corresponding to TRP1 and TRP2.

[0069]

[0087] According to another method (method 4 shown in Figure 11), the repetition can be performed across slots. In this case, up to 16 repetitions can be permitted across two TCI states. In Figure 11, an example of 8 repetitions is shown. The TCI state pattern can also be configurable (e.g., 12121212 vs. 11221122), and the RV pattern for each TCI state follows the current standard (e.g., Release 15, i.e., RV0-2-3-1). The RV offset can be configured to be an RV offset.

[0070] Exemplary method for PMI, RI, and port indexing of mTRP CSI

[0088] Aspects of the present disclosure relate to wireless communication in techniques, and more particularly, to techniques for reporting channel state information (CSI) such as a precoding matrix indicator (PMI) and a layer indicator (LI) in a multi-transmit and receive point (mTRP) scenario.

[0071]

[0089] FIG. 12 shows exemplary CSI-RS reporting and resource configurations for different mTRP CSI categories. Depending on the category, the UE has different ways of indicating whether it prefers a single TRP (to communicate only with TRP0 or only with TRP1) or an mTRP (to communicate with TRP0 and TRP1).

[0072]

[0090] As shown, for the first category (category 1.1), the resources for a single reporting configuration (reporting configuration 0) include at least two resources, where each resource is configured with a single TCI state (this means that each resource corresponds to a single TRP, in other words, all ports within the resource are transmitted from one TRP). Based on CSI-RS measurements, the UE may indicate a single TRP (TRP0 or TRP1) by reporting a CSI-RS resource indicator (CRI) value of 0 or 1. The UE may indicate an mTRP by reporting a CRI value of 2.

[0073]

[0091] As shown, for the second category (category 1.2), the resources for a single reporting configuration (reporting configuration 0) include two CSI-RS port groups with two TCI states per resource (one TCI state per port group indicates that the port group corresponds to a single TRP, in other words, the ports within one port group are transmitted from one TRP). Based on CSI-RS measurements, the UE may indicate a single TRP (TRP0 or TRP1) by reporting a rank indicator (RI) value of 0 for one of the CSI-RS port groups.

[0074] (RI0>0,0) indicates TRP0, or (0,RI1>0) indicates TRP1. The UE can indicate mTRP by reporting non-zero RI values for both.

[0075] (RI0>0,RI1>0) indicates mTRP.

[0076]

[0092] Category 1.2 can also be mixed with Category 1.1. That is, a certain resource can have a single TCI state, while some others have two port groups each with a TCI state. Based on CSI measurement, the UE can report the CRI corresponding to the resource with a single TCI state when the UE selects single-TRP transmission, or the UE can report the CRI corresponding to the resource with two TCI states when the UE selects multi-TRP transmission.

[0077]

[0093] As shown, for the third category (Category 2), the two reporting configurations (Reporting Configuration 0 and Reporting Configuration 1) can each include a CSI-RS port group with a single TCI state. Based on CSI-RS measurement, the UE can indicate a single TRP (TRP0 or TRP1) by reporting the same 0 CRI value for both Report 0 and Report 1. The UE can indicate mTRP by reporting a CRI value of 1 for both Report 0 and Report 1.

[0078]

[0094] These current reporting and resource configurations present various potential issues. For example, since the CSI-RS resources for each TRP occupy a subset of resource blocks (RBs) across the frequency resources allocated, one issue is how to transmit CSI-RS and / or how to report CSI assuming an FDM'd mTRP pattern.

[0079]

[0095] Another potential issue for all SDM, FDM, and TDM schemes where the PTRS ports need to be associated with the strongest layer (DMRS ports) per TRP is how to determine and report the strongest layer per TRP.

[0080]

[0096] Yet another issue in the CSI reporting framework where CSI is calculated per port group rather than for all ports in the resource (e.g., for category 1.2) is how to clarify port indexing in the PMI / CQI calculation.

[0081]

[0097] Aspects of the present disclosure present various techniques (configurations and reporting schemes) to address these potential issues. For example, FIGS. 13 and 14 show exemplary UE and network-side operations for reporting PMI per CSI-RS resource or per port group on respective frequency units.

[0082]

[0098] FIG. 13 shows an exemplary operation 1300 for wireless communication according to some aspects of the present disclosure. Operation 1300 may be performed by a UE (such as UE 120 in wireless communication network 100, for example).

[0083]

[0099] Operation 1300 starts at 1302 and receives, from a network entity, a CSI reporting configuration indicating at least first and second CSI reference signal (CSI-RS) resources or port groups related to channel state information (CSI) reports. For example, the UE may receive at least two CSI-RS resources (per category 1.1) or at least two CSI-RS port groups (per category 1.2) related to one or more CSI reports (per category 2). The UE may receive the CSI reporting configuration, for example, via any suitable detection and decoding algorithms, via the antennas and receiver / transceiver components of the UE120a shown in FIG. 4 and / or the device shown in FIG. 21.

[0084]

[0100] At 1304, the UE performs CSI measurements based on a frequency division multiplexing (FDM) scheme comprising transmission via a first resource or port group on a first set of FD units and transmission via a second resource or port group on a second set of FD units. The UE may perform CSI measurements, for example, using any suitable detection and algorithms for calculating CSI metrics, based on the CSI-RS signals received via the antennas, receiver / transceiver components, and processor of the UE120a shown in FIG. 4 and / or the device shown in FIG. 21.

[0085]

[0101] At 1306, the UE transmits to the network entity a PMI report indicating a first set of one or more precoding matrix indicators (PMIs) related to ports in a first resource or port group on a first set of FD units and a second set of one or more PMIs related to ports in a second resource or port group on a second set of FD units. The UE may transmit the PMI report, for example, using any suitable encoding and transmission algorithms, via the antennas and receiver / transceiver components of the UE120a shown in FIG. 4 and / or the device shown in FIG. 21.

[0086]

[0102] FIG. 14 shows an exemplary operation 1400 for wireless communication that can be considered complementary to operation 1300 of FIG. 13. For example, operation 1400 may be performed by a network entity (such as BS110 in wireless communication network 100 or a CU / DU controlling a plurality of TRPs) to configure and process a PMI report from a UE performing operation 1300 of FIG. 13.

[0087]

[0103] Operation 1400 begins at 1402 and transmits to a user equipment (UE) a CSI report configuration indicating at least first and second CSI reference signal (CSI-RS) resources or port groups related to a channel state information (CSI) report. At 1404, the network entity transmits CSI-RS based on a frequency division multiplexing (FDM) scheme comprising transmission via a first resource or port group on a first set of FD units and transmission via a second resource or port group on a second set of FD units. For example, the network entity may transmit the CSI report configuration and the CSI-RS (e.g., via RRC signaling) via the antennas and receiver / transceiver components of BS110a shown in FIG. 4 and / or the apparatus shown in FIG. 21 using any suitable encoding and transmission algorithms.

[0088]

[0104] At 1406, the network entity receives from the UE a PMI report indicating a first set of one or more precoding matrix indicators (PMIs) related to a first resource or ports in a first set of FD units or a port group and a second set of one or more PMIs related to a second resource or ports in a second set of FD units or a port group. For example, the network entity may receive the PMI report via the antennas and receiver / transceiver components of BS110a shown in FIG. 4 and / or the device shown in FIG. 21 using any suitable detection and decoding algorithms.

[0089]

[0105] In this way, in the FDM mode, the UE may report PMI for each CSI-RS resource or port group on each frequency unit. FIG. 15 shows an example of how different (first and second) sets of frequency domain (FD) units (e.g., subbands) may be assigned to different TRPs (as CSI resources or port groups). As shown in FIG. 15, a first set of FD units (subbands) is assigned to TRP1 (resource / port group 1) or TRP2 (resource / port group 2), while a second set of FD units (subbands) is assigned to TRP1 (resource / port group 1) or TRP2 (resource / port group 2). As illustrated, the first set of FD units may comprise even subbands, while the second set of FD units may comprise odd subbands. Alternatively, a finer PMI granularity such as a PRG (smaller than the subband size) may be configured, in which case the first FD unit set may comprise even PRGs, while the second set of FD units may comprise odd PRGs. Another alternative is that the first FD unit set may comprise the first half of all FD units (the first half of all subbands), while the second FD unit set may comprise the second half of all FD units (the second half of all subbands).

[0090]

[0106] In some cases, the UE may determine an FDM-based transmission assumption that uses a first CSI-RS resource or port group on a first set of FD units and a second CSI-RS resource or port group on a second set of FD units. The UE may perform CSI measurements and reporting on the use of a first set of PMIs associated with the first CSI-RS resource or port group on the first set of FD units and a second set of PMIs associated with the second CSI-RS resource or port group on the second set of FD units.

[0091]

[0107] There are various options for how the UE may determine the transmission (e.g., FDM scheme). According to one option, the UE may receive a configuration of the FDM scheme in the CSI reporting configuration. According to another option, the UE may determine the transmission scheme from a set of candidate scheme hypotheses. Each candidate scheme may comprise, for example, an SDM scheme, an FDM scheme, or a TDM scheme. In such a case, the UE may report the UE report, the selected (FDM) scheme.

[0092]

[0108] There are various options for how to determine the division of frequency domain resource allocation FDRA (for example, the first / second set of FD units shown in FIG. 15). For example, the UE may determine whether the FDRA indicates whether the FD units are consecutive in the first and second halves of the FDRA (left figure in FIG. 8) or interleaved (right figure in FIG. 8). In some cases, this information may be configured by the network (for example, via a 1-bit indicator in the CSI reporting configuration or via a PRG / subband-group indicator for indicating WB, where PRG = 2 or 4). More specifically, with a 1-bit indication, code point 0 (or 1) may indicate that the division of the FDRA is the first and second halves, while code point 1 (or 0) may indicate that the division of the FDRA is interleaved. More specifically, when configured with WB granularity, the division of the FDRA may be the first and second halves, and when configured with PRG = 2 or 4, the division of the FDRA may be interleaved based on the PRG comb (even PRG and odd PRG), and when configured with subband grouping information (for example, two subbands in a group), the division of the FDRA may be interleaved based on the subband group comb (even subband group and odd subband group).

[0093]

[0109] In some cases, the UE may determine the FDRA based on the actual CSI-RS transmission. For example, the UE may be able to detect that the first CSI-RS resource or port group is transmitted only on the first half, and the second CSI-RS resource or port group is transmitted only on the second half. Similarly, the UE may detect that the first CSI-RS resource or port group is transmitted only on even (or odd) subbands / RBs / PRGs / subband groups, and the second CSI-RS resource or port group is transmitted only on odd (or even) subbands / RBs / PRGs / subband groups, which indicates that they are interleaved. The UE may report the determination of the FDRA.

[0094]

[0110] When the determination is that the FDRA is the first / second half, the first set of FD units is the first or second half of all CSI reporting subbands or RBs. When the determination is that the FDRA is interleaved, the first set of FD units is the odd or even subbands / RBs / PRGs / subband groups. The (indicating which TRP the first / second half or odd / even is assigned to) TRP order can be configured by the network (e.g., via a 1-bit indicator). In some cases, the (indicating which TRP the first / second half or odd / even is assigned to) TRP order can be reported by the UE. In some cases, the FDRA (first / second half or interleaved) and / or the TRP order can be configured (or reported) together in an FDM manner. More specifically, generally, there are four assumptions for the FDM manner, e.g., {TRP1 on the first half, TRP2 on the second half}, {TRP1 on the second half, TRP2 on the first half}, {TRP1 on the even FD units, TRP2 on the odd FD units}, and {TRP1 on the odd FD units, TRP2 on the even FD units}. In some cases, the network can directly configure one of these for the assumption. In some cases, the network can configure the FDRA division as the first / second half, and the UE may need to report the TRP order from {TRP1 on the first half, TRP2 on the second half}, {TRP1 on the second half, TRP2 on the first half}, or the network can configure the FDRA division as interleaved (even / odd FD units), and the UE may need to report the TRP order from {TRP1 on the even FD units, TRP2 on the odd FD units} and {TRP1 on the odd FD units, TRP2 on the even FD units}.In some cases, the network may configure the TRP order as TRP1 on the first set of FD units and TRP2 on the second set of FD units, and the UE may need to report the FDRA partition from {TRP1 on the first half, TRP2 on the second half} and {TRP1 on even-numbered FD units, TRP2 on odd-numbered FD units}, or the network may configure the TRP order as TRP2 on the first set of FD units and TRP1 on the second set of FD units, and the UE may need to report the FDRA partition from {TRP2 on the first half, TRP1 on the second half} and {TRP2 on even-numbered FD units, TRP1 on odd-numbered FD units}. In some other cases, the UE may report one of four assumptions.

[0095]

[0111] The first CSI-RS resource or port group may be transmitted on the first set of FD units, while the second CSI-RS resource or port group may be transmitted on the second set of FD units.

[0096]

[0112] The total number of precoding matrices reported in each set of PMIs may be determined at least partially based on the number of subbands in the corresponding set of FD units. For example, eType If type-II CSI is applied to either the first or the second set of PMIs, the number N3 of precoding matrices (size of the FD compression matrix) may be a function of the number of subbands in the corresponding set of FD units and a higher-layer parameter (e.g., numberOfPMISubbandsPerCQISubband-r16).

[0097]

[0113] Figures 16 and 17 show exemplary UE and network-side operations for reporting LI pairs. For example, each LI may be associated with one of the PMIs for each CSI-RS resource or port group on its respective frequency unit.

[0098]

[0114] Figure 16 shows an exemplary operation 1600 for wireless communication according to some aspects of the present disclosure. Operation 1600 may be performed by a UE (such as UE 120 in wireless communication network 100, for example).

[0099]

[0115] Operation 1600 starts at 1602 and determines a transmission mode for CSI reporting using at least first and second channel state information (CSI) reference signal (CSI-RS) resources or port groups. At 1604, the UE performs CSI measurements based on CSI-RS transmissions sent via at least the first and second CSI-RS resources or port groups. The UE may determine the transmission mode and perform CSI measurements based on CSI-RS signals received, for example, via the antennas, receiver / transceiver components, and processors of UE 120a shown in FIG. 4 and / or the apparatus shown in FIG. 21, using any suitable detection and algorithms.

[0100]

[0116] At 1606, the UE transmits a PMI report to a network entity indicating a first set of one or more precoding matrix indicators (PMIs) associated with a first resource or port group, a second set of one or more PMIs associated with a second resource or port group, a first layer indicator (LI) associated with the first set of PMIs, and a second LI associated with the second set of PMIs. The UE may transmit the PMI report, for example, using any suitable encoding and transmission algorithms, via the antennas and receiver / transceiver components of UE 120a shown in FIG. 4 and / or the apparatus shown in FIG. 21.

[0101]

[0117] FIG. 17 shows an exemplary operation 1700 for wireless communication that can be considered complementary to operation 1600 of FIG. 16. For example, operation 1700 may be performed by a network entity (such as BS110 or a CU / DU controlling a plurality of TRPs in wireless communication network 100) to configure and process a PMI report from a UE performing operation 1600 of FIG. 16.

[0102]

[0118] Operation 1700 begins at 1702, and transmits a CSI reference signal (CSI-RS) to a user equipment (UE) according to a transmission scheme using at least first and second channel state information (CSI) reference signal (RS) resources or port groups. For example, the network entity may transmit the CSI-RS via the antennas and receiver / transceiver components of BS110a shown in FIG. 4 and / or the device shown in FIG. 21 using any suitable encoding and transmission algorithms.

[0103]

[0119] At 1704, the network entity receives from the UE a PMI report indicating a first set of one or more precoding matrix indicators (PMIs) associated with a first resource or port group, a second set of one or more PMIs associated with a second resource or port group, a first layer indicator (LI) associated with the first set of PMIs, and a second LI associated with the second set of PMIs. For example, the network entity may receive the PMI report via the antennas and receiver / transceiver components of BS110a shown in FIG. 4 and / or the device shown in FIG. 21 using any suitable detection and decoding algorithms.

[0104]

[0120] In this way, the UE can determine the transmission method for CSI reporting using two CSI-RS resources or two CSI port groups, and can report two LIs. In other words, of the two LIs, one LI is measured using one of the two CSI-RS resources or port groups and is associated with the reported PMI, while the other LI is measured using the other of the two CSI-RS resources or port groups and is associated with the reported PMI. In this way, each LI indicates the strongest layer among the layers indicated by the respective PMI. The transmission method can be SDM, FDM, TDM, or a single frequency network (SFN) method.

[0105]

[0121] In the current system, the PMI is generally calculated for each resource using, for example, CSI-RS ports 3000 to 3000 + P - 1 (where P is the number of ports). In the current system, the CQI is generally calculated based on the virtual PDSCH layers mapped to CSI-RS ports 3000 to 3000 + P - 1. The mapping is performed via the calculated PMI (e.g., matrix W(i)). In each CSI-RS resource, the port indexing is from 3000 to 3000 + P - 1.

[0106]

[0122] One potential issue in the current system (e.g., using category 1.2) is that one PMI is calculated using the first port group and another PMI is calculated using the second port group, which means that the associated port index for the PMI and CQI must be changed.

[0107]

[0123] FIGS. 18 and 19 show exemplary UE and network-side operations for CSI reporting using CSI-RS port indexing. For example, the UE can perform PMI and CQI measurements using the CSI-RS port index in each port group.

[0108]

[0124] Figure 18 shows an exemplary operation 1800 for wireless communication according to some aspects of the present disclosure. The operation 1800 may be performed by a UE (such as UE 120 in the wireless communication network 100 for example).

[0109]

[0125] The operation 1800 begins at 1802 and receives from a network entity a channel state information (CSI) reporting configuration, the configuration indicating at least one CSI - RS resource comprising at least first and second CSI reference signal (CSI - RS) port groups. For example, the UE may receive the CSI reporting configuration via, for example, the antennas and receiver / transceiver components of the UE 120a shown in FIG. 4 and / or the device shown in FIG. 21 using any suitable detection and decoding algorithms.

[0110]

[0126] At 1804, the UE determines a CSI codebook associated with each CSI - RS port for precoding matrix indicator (PMI) and channel quality indicator (CQI) measurements. At 1806, the UE uses the determined CSI codebook and the CSI - RS port indices in each CSI - RS port group to perform PMI and CQI measurements by reporting a first PMI mapped to the port index in the first group and a second PMI mapped to the port index in the second group. The UE may determine the CSI codebook and perform CSI measurements based on signals received via, for example, the antennas, receiver / transceiver components, and processor of the UE 120a shown in FIG. 4 and / or the device shown in FIG. 21 using any suitable detection and algorithms.

[0111]

[0127] In 1806, the UE may send a PMI report to a network entity indicating a first set of one or more precoding matrix indicators (PMI) associated with a first resource or ports in a first set of FD units or a port group and a second set of one or more PMI associated with a second resource or ports in a second set of FD units or a port group. The UE may transmit the PMI report, for example, using any suitable encoding and transmission algorithm, via, for example, the antennas and receiver / transceiver components of the UE120a shown in FIG. 4 and / or the apparatus shown in FIG. 21.

[0112]

[0128] FIG. 19 shows an exemplary operation 1900 for wireless communication that may be considered complementary to operation 1800 of FIG. 18. For example, operation 1900 may be performed by a network entity (such as BS110 or a CU / DU controlling a plurality of TRPs in the wireless communication network 100) to configure and process a CSI report using CSI-RS port indexing from a UE performing operation 1800 of FIG. 18.

[0113]

[0129] Operation 1900 begins at 1902 and transmits to a user equipment (UE) a CSI report configuration indicating at least one CSI-RS resource comprising at least first and second channel state information (CSI) reference signal (CSI-RS) port groups. For example, the network entity may transmit the CSI report configuration and the CSI-RS (e.g., via RRC signaling) via the antennas and receiver / transceiver components of the BS110a shown in FIG. 4 and / or the apparatus shown in FIG. 21 using any suitable encoding and transmission algorithm.

[0114]

[0130] In 1904, the network entity determines a CSI codebook associated with each CSI-RS port for precoding matrix indicator (PMI) and channel quality indicator (CQI) measurements. For example, the network entity may determine the CSI codebook based on signals received, for example, via the antennas and receiver / transceiver components and processors of the BS110a shown in FIG. 4 and / or the apparatus shown in FIG. 21, using any suitable detection and algorithms.

[0115]

[0131] In 1906, the network entity receives, from the UE, a report of a first PMI mapped to a port index in a first group and a second PMI mapped to a port index in a second group, based on PMI and CQI measurements performed by the UE using the CSI codebook determined using the CSI-RS port indices in each CSI-RS port group. For example, the network entity may receive the PMI report via the antennas and receiver / transceiver components of the BS110a shown in FIG. 4 and / or the apparatus shown in FIG. 21, using any suitable detection and decoding algorithms.

[0116]

[0132] CSI-RS reporting using CSI-RS port indexing can be understood with reference to FIGS. 20A to 20C, which show how a UE can determine a PMI using ports having indexes starting from 3000 + p_{i,offset} for different numbers of antenna ports and different codebook type configurations, where 3000 + p_{i,offset} is the port index of the first port in the i-th port group in the CSI-RS resource. In some cases, p_{i,offset} is the total number of ports in a port group having a group index smaller than i. In some cases, p_{i,offset} is the offset between the first port in the i-th port group and the first port in the resource. In some cases, if each group has p ports, p_{i,offset}=p*(i - 1) if the first group index is 1, or p_{i,offset}=p*i if the first group index is 0.

[0117]

[0133] Figure 20A shows how a UE can determine a PMI using port indexing for 4 to 32 antenna ports when configured with a higher layer parameter codebookType set to "typeI-SinglePannel / typeII / typeII-PortSelection / typeII-r16 / typeII-PortSelection-r16". Figure 20B shows how a UE can determine a PMI using port indexing for 8 to 32 antenna ports when configured with a higher layer parameter codebookType set to "typeI-MultiPanel". Figure 20C shows how a UE can determine a PMI using port indexing for two antenna ports when configured with a higher layer parameter codebookType set to "typeI-SinglePanel". In each case, if no port group is configured, i can be set to 0 (essentially reverting to a CSI-RS report that is not indexed to a conventional port).

[0118]

[0134] In the case of the SDM method, for CQI calculation, the UE may assume that the PDSCH signal on the antenna ports in the set [1000,..., 1000 + ν - 1] for the ν layers will result in a signal corresponding to the corresponding symbol transmitted on the antenna ports [3000,..., 3000 + P - 1] as given by the following equation.

[0119]

Number

[0120] Here, W1 can be calculated using a first port group having indices from 3000 to 3000 + P1 - 1, and there are v1 layers provided in W1 and W2 that can be calculated using a second port group having indices from 3000 + P1 to 3000 + P - 1, and there are v - v1 layers provided in W2, where P1 is the number of ports in the first port group, while P is the total number of ports in the resource.

[0121]

[0135] In the case of the TDM and FDM schemes, for CQI calculation, the UE determines that for the PDSCH signal on the antenna ports in the set [1000,..., 1000 + ν - 1] for the ν layers, in the case of the FDM scheme, it is on the first set of FD units or in the case of the TDM scheme, it is on the first set of TD units.

[0122]

Number

[0123] is given by, in the case of the FDM scheme, on the second set of FD units or in the case of the TDM scheme, on the second set of TD units.

[0124]

Number

[0125] It can be assumed that it will generate a signal corresponding to the corresponding symbol transmitted on the antenna ports [3000,..., 3000 + P - 1] as given by, where the layers mapped to W1 and W2 are the same layers from the same TB. The mapping procedure can follow the layer mapping defined for the mTRP FDM and TDM schemes (for example, as described with reference to FIG. 9).

[0126]

[0136] FIG. 21 shows a communication device 2100 that may include various components configured to perform operations for techniques disclosed herein, such as the operations shown in FIGS. 13, 14, 16, 17, 18, and / or 19 (e.g., corresponding to means-plus-function components). The communication device 2100 includes a processing system 2102 coupled to a transceiver 2108. The transceiver 2108 is configured to transmit and receive signals for the communication device 2100, such as the various signals described herein, via an antenna 2110. The processing system 2102 may be configured to perform processing functions for the communication device 2100, including processing signals to be received and / or transmitted by the communication device 2100.

[0127]

[0137] The processing system 2102 includes a processor 2104 coupled to a computer-readable medium / memory 2112 via a bus 2106. In some aspects, the computer-readable medium / memory 2112 is configured to store instructions (e.g., computer-executable code) that, when executed by the processor 2104, cause the processor 2104 to perform the operations shown in FIGS. 13, 14, 16, 17, 18, and / or 19. In some aspects, the computer-readable medium / memory 2112 stores code 2114 for determining, code 2116 for transmitting, code 1018 for receiving, and code 1019 for performing. In some aspects, the processor 1004 has circuitry configured to implement the code stored in the computer-readable medium / memory 1012. The processor 1004 includes circuitry 1022 for determining, circuitry 1024 for transmitting, circuitry 1026 for receiving, and circuitry 1028 for performing.

[0128]

[0138] The method disclosed in this specification comprises one or more steps or actions for achieving the method. The steps and / or actions of the method can be exchanged with each other without departing from the scope of the claims. In other words, unless a specific order of steps or actions is specified, the order and / or use of specific steps and / or actions can be changed without departing from the scope of the claims.

[0129] Exemplary embodiments

[0139] Embodiment 1: A method for wireless communication by a user equipment (UE), comprising receiving, from a network entity, a CSI reporting configuration indicating at least a first and a second CSI reference signal (CSI-RS) resource or port group related to a channel state information (CSI) report; performing CSI measurements based on a frequency division multiplexing (FDM) scheme comprising transmission via a first resource or port group on a first set of FD units and transmission via a second resource or port group on a second set of FD units; and transmitting to the network entity a PMI report indicating a first set of one or more precoding matrix indicators (PMI) related to ports in the first resource or port group on the first set of FD units and a second set of one or more PMI related to ports in the second resource or port group on the second set of FD units.

[0130]

[0140] Embodiment 2: The method according to Embodiment 1, wherein the FD unit comprises a sub-band or a PRG.

[0131]

[0141] Embodiment 3: The method according to Embodiment 2, further comprising receiving a configuration indicating the FDM scheme.

[0132]

[0142] Aspect 4: The method according to aspect 2, further comprising selecting an FDM method from a set of candidate schemes and reporting the selected FDM method to a network entity.

[0133]

[0143] Aspect 5: The method according to any one of aspects 1 to 3, further comprising receiving an indication of frequency domain resource allocation (FDRA) indicating whether the first and second sets of FD units are interleaved or span a continuous set of FD units.

[0134]

[0144] Aspect 6: The method according to aspect 5, wherein the indication is given via a CSI reporting configuration or via a precoding block resource group (PRG) or a subband group indicator.

[0135]

[0145] Aspect 7: The method according to aspect 6, wherein the configuration comprises a joint configuration of an FDM method for CSI measurement, an FDRA of a first set of FD units for a first resource or port group, and an FDRA of a first set of FD units for a second resource or port group of the FD units.

[0136]

[0146] Aspect 8: The method according to any one of aspects 1 to 7, further comprising determining whether the first and second sets of FD units are interleaved or span a continuous set of FD units based on an actual CSI-RS transmission.

[0137]

[0147] Aspect 9: The method according to any one of Aspects 1 to 8, further comprising selecting a candidate frequency division resource allocation (FDRA) for the first and second sets of FD units from a set of candidate FDRAs, and reporting the selected FDRA to a network entity.

[0138]

[0148] Aspect 10: The method according to Aspect 9, wherein the report indicates together an FDM scheme and its FDRA from a set of candidate schemes selected by a UE.

[0139]

[0149] Aspect 11: The total number of precoding matrices reported in the first set of PMIs is determined at least in part based on the number of sub-bands in the first set of FD units, and the total number of precoding matrices reported in the second set of PMIs is determined at least in part based on the number of sub-bands in the second set of FD units. The method according to any one of Aspects 1 to 10.

[0140]

[0150] Aspect 12: When a certain type of CSI is applied to either the first set of PMIs or the second set of PMIs, the number of precoding matrices reported is a function of a configured parameter composed with the number of sub-bands in the corresponding set of FD units. The method according to any one of Aspects 1 to 11.

[0141]

[0151] Aspect 13: A method for wireless communication by a user equipment (UE), comprising determining a transmission mode for CSI reporting using at least first and second channel state information (CSI) reference signal (CSI-RS) resources or port groups; performing CSI measurements based on CSI-RS transmissions sent via at least the first and second CSI-RS resources or port groups; and transmitting to a network entity a PMI report indicating a first set of one or more precoding matrix indicators (PMI) associated with the first resource or port group, a second set of one or more PMI associated with the second resource or port group, a first layer indicator (LI) associated with the first set of PMI, and a second LI associated with the second set of PMI.

[0142]

[0152] Aspect 14: The method according to aspect 13, wherein the transmission mode comprises spatial division multiplexing (SDM).

[0143]

[0153] Aspect 15: The method according to any one of aspects 13 to 14, wherein the transmission mode comprises time division multiplexing (TDM).

[0144]

[0154] Aspect 16: The method according to any one of aspects 13 to 15, wherein the transmission mode comprises frequency division multiplexing (FDM).

[0145]

[0155] Aspect 17: The method according to aspect 16, wherein the first CSI measurement is performed based on a first CSI-RS resource or port group received on a first set of frequency domain (FD) units, and the second CSI measurement is performed based on a second CSI-RS resource or port group received on a second set of FD units.

[0146]

[0156] Aspect 18: The method according to any one of Aspects 13 to 17, wherein the first LI indicates the strongest layer among the layers indicated by the first set of PMIs, and the second LI indicates the strongest layer among the layers indicated by the second set of PMIs.

[0147]

[0157] Aspect 19: A method for wireless communication by a user equipment (UE), comprising receiving, from a network entity, a channel state information (CSI) reporting configuration, the configuration indicating at least one CSI-RS resource comprising at least first and second CSI reference signal (CSI-RS) port groups, determining a CSI codebook associated with each CSI-RS port for precoding matrix indicator (PMI) and channel quality indicator (CQI) measurements, and performing PMI and CQI measurements by using the determined CSI codebook and using the CSI-RS port indices in each CSI-RS port group to report a first PMI mapped to the port index in the first group and a second PMI mapped to the port index in the second group.

[0148]

[0158] Aspect 20: The method according to Aspect 19, wherein the CQI measurement depends at least in part on the transmission mode used for CSI RS reporting.

[0149]

[0159] Aspect 21: The method according to Aspect 20, wherein when the transmission mode comprises a spatial division multiplexing (SDM) mode, the UE calculates the CQI assuming a physical downlink shared channel (PDSCH) based on a first mapping from a first set of layers to a first port group having a first index via a first precoding matrix indicated by the first PMI and a second mapping from a second set of layers to a second port group having a second index via a second precoding matrix indicated by the second PMI.

[0150]

[0160] Aspect 22: When the transmission mode includes a frequency division multiplexing (FDM) mode, the UE calculates the CQI assuming a physical downlink shared channel (PDSCH) based on a first precoding matrix indicator (PMI) that maps a first layer to a first port group on a first set of frequency domain (FD) units and a second PMI that maps a second layer to a second port group on a second set of FD units, according to any one of Aspects 19 to 21.

[0151]

[0161] Aspect 23: When the transmission mode includes a time division multiplexing (TDM) mode, the UE calculates the CQI assuming a physical downlink shared channel (PDSCH) based on a first precoding matrix indicator (PMI) that maps a first layer to a first port group on a first set of time domain (TD) units and a second PMI that maps a second layer to a second port group on a second set of TD units, according to any one of Aspects 19 to 22.

[0152]

[0162] Aspect 24: A method for wireless communication by a network entity, comprising: transmitting to a user equipment (UE) a CSI report configuration indicating at least first and second CSI reference signal (CSI-RS) resources or port groups related to channel state information (CSI) reporting; transmitting CSI-RS based on a frequency division multiplexing (FDM) mode comprising transmission via a first resource or port group on a first set of FD units and transmission via a second resource or port group on a second set of FD units; and receiving from the UE a PMI report indicating a first set of one or more precoding matrix indicators (PMI) related to ports in a first resource or port group on a first set of FD units and a second set of one or more PMI related to ports in a second resource or port group on a second set of FD units.

[0153]

[0163] Aspect 25: The method according to Aspect 24, wherein the FD units comprise sub-bands or physical resource blocks (PRBs).

[0154]

[0164] Aspect 26: The method according to aspect 25, further comprising transmitting, to the UE, a configuration indicating the FDM scheme.

[0155]

[0165] Aspect 27: The method according to any one of aspects 24 to 25, further comprising sending, to the UE, a set of candidate schemes and receiving, from the UE, a report indicating an FDM scheme selected from the set of candidate schemes.

[0156]

[0166] Aspect 28: The method according to any one of aspects 24 to 27, further comprising giving, to the UE, an indication of frequency domain resource allocation (FDRA) indicating whether the first and second sets of FD units are interleaved or over a continuous set of FD units.

[0157]

[0167] Aspect 29: The method according to aspect 28, wherein the indication is given via a CSI reporting configuration or via a precoding block resource group (PRG) or a subband group indicator.

[0158]

[0168] Aspect 30: The method according to aspect 29, wherein the configuration comprises a joint configuration of an FDM scheme for CSI measurement, an FDRA of a first set of FD units for a first resource or port group, and an FDRA of a first set of FD units for a second resource or port group of the first set of FD units.

[0159]

[0169] Aspect 31: The method according to any one of aspects 24 to 30, further configured to send, to the UE, a set of candidate frequency domain resource allocations (FDRAs) and receive, from the UE, an indication of an FDRA selected from the set of candidate FDRAs.

[0160]

[0170] Aspect 32: The method according to aspect 31, wherein the indication indicates together an FDM scheme from a set of candidate schemes selected by the UE and its FDRA.

[0161]

[0171] Aspect 33: The total number of precoding matrices reported in the first set of PMIs is determined at least in part based on the number of subbands in the first set of FD units, and the total number of precoding matrices reported in the second set of PMIs is determined at least in part based on the number of subbands in the second set of FD units, the method according to any one of Aspects 24 to 32.

[0162]

[0172] Aspect 34: When a certain type of CSI is applied to either the first set of PMIs or the second set of PMIs, the number of precoding matrices reported is a function of the number of subbands in the corresponding set of FD units and a configured parameter, the method according to any one of Aspects 24 to 33.

[0163]

[0173] Aspect 35: A method for wireless communication by a network entity, comprising transmitting a CSI reference signal (CSI-RS) to a user equipment (UE) according to a transmission mode using at least first and second channel state information (CSI) reference signal (RS) resources or port groups, and receiving from the UE a PMI report indicating a first set of one or more precoding matrix indicators (PMIs) associated with the first resource or port group, a second set of one or more PMIs associated with the second resource or port group, a first layer indicator (LI) associated with the first set of PMIs, and a second LI associated with the second set of PMIs.

[0164]

[0174] Aspect 36: The transmission mode comprises spatial division multiplexing (SDM), the method according to Aspect 35.

[0165]

[0175] Aspect 37: The transmission mode comprises time division multiplexing (TDM), the method according to any one of Aspects 35 to 36.

[0166]

[0176] Aspect 38: The transmission method is the method according to any one of Aspects 35 to 37, comprising frequency division multiplexing (FDM).

[0167]

[0177] Aspect 39: The first LI indicates the strongest layer among the layers indicated by the first set of PMIs, and the second LI indicates the strongest layer among the layers indicated by the second set of PMIs, the method according to Aspects 35 to 38.

[0168]

[0178] A method for wireless communication by a network entity, comprising transmitting to a user equipment (UE) a CSI reporting configuration indicating at least one CSI-RS resource comprising at least first and second channel state information (CSI) reference signal (CSI-RS) port groups; determining a CSI codebook associated with each CSI-RS port for precoding matrix indicator (PMI) and channel quality indicator (CQI) measurements; receiving from the UE a report of a first PMI mapped to a port index in a first group and a second PMI mapped to a port index in a second group, based on PMI and CQI measurements performed by the UE using the CSI codebook determined using the CSI-RS port indices in each CSI-RS port group.

[0169]

[0179] Aspect 41: The CQI measurement depends at least in part on the transmission method used for CSI RS reporting, the method according to Aspect 40.

[0170]

[0180] Aspect 42: When the transmission mode includes a spatial division multiplexing (SDM) mode, the UE calculates the CQI assuming a physical downlink shared channel (PDSCH) based on the first mapping from the first set of layers to the first port group having the first index via the first precoding matrix indicated by the first PMI and the second mapping from the second set of layers to the second port group having the second index via the second precoding matrix indicated by the second PMI. The method according to aspect 41.

[0171]

[0181] Aspect 43: When the transmission mode includes a frequency division multiplexing (FDM) mode, the UE calculates the CQI assuming a physical downlink shared channel (PDSCH) based on the first PMI that maps the first layer to the first port group on the first set of frequency domain (FD) units and the second PMI that maps the second layer to the second port group on the second set of FD units. The method according to any one of aspects 40 to 42.

[0172]

[0182] Aspect 44: When the transmission mode includes a time division multiplexing (TDM) mode, the UE calculates the CQI assuming a physical downlink shared channel (PDSCH) based on the first PMI that maps the first layer to the first port group on the first set of time domain (TD) units and the second PMI that maps the second layer to the second port group on the second set of TD units. The method according to any one of aspects 40 to 43.

[0173]

[0183] Aspect 45: An apparatus comprising at least one processor and a memory configured to perform the operations of the method according to any one of aspects 1 to 44.

[0174]

[0184] Aspect 46: An apparatus comprising means for performing the operations of the method according to any one of aspects 1 to 44.

[0175]

[0185] A computer-readable medium storing instructions for performing the operations of the method according to any one of Aspects 1 to 44.

[0176]

[0186] As used herein, the phrase "at least one of" in a list of items refers to any combination of those items, including a single member. By way of example, "at least one of a, b, or c" includes a, b, c, a - b, a - c, b - c, and a - b - c, as well as any combination having multiple of the same element (e.g., a - a, a - a - a, a - a - b, a - a - c, a - b - b, a - c - c, b - b, b - b - b, b - b - c, c - c, and c - c - c, or any other order of a, b, and c).

[0177]

[0187] As used herein, the term "determining" encompasses a wide variety of actions. For example, "determining" can include calculating, computing, processing, deriving, investigating, looking up (e.g., looking up in a table, database or another data structure), ascertaining, etc. Also, "determining" can include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory), etc. Also, "determining" can include resolving, selecting, choosing, establishing, etc.

[0178]

[0188] The foregoing description has been provided to enable a person of ordinary skill in the art to make and use the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. Accordingly, the claims are not intended to be limited to the aspects shown herein but are to be accorded the full scope consistent with the language of the claims, where reference to a singular element is not intended to mean "one and only one" unless specifically so stated, but rather "one or more." Unless specifically stated otherwise, the term "some" refers to one or more. All structural and functional equivalents of the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is dedicated to the public regardless of whether such disclosure is expressly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. § 112(f) unless the element is expressly recited using the phrase "means for" or, in the case of a method claim, the element is expressly recited using the phrase "step for."

[0179]

[0189] The various operations of the methods described above may be performed by any suitable means capable of performing the corresponding functions. These means may include, but are not limited to, various (one or more) hardware and / or software components and / or modules including circuits, application specific integrated circuits (ASICs), or processors. Generally, where there are operations shown in the figures, those operations may have corresponding counterpart means-plus-function components with similar numbers.

[0180]

[0190] Various illustrative logical blocks, modules, and circuits described in connection with the present disclosure may be implemented or executed using a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device (PLD), discrete gates or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any commercially available processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0181]

[0191] When implemented in hardware, an exemplary hardware configuration may include a processing system in a wireless node. The processing system may be implemented using a bus architecture. The bus may include any number of interconnecting buses and bridges, depending on the specific application of the processing system and overall design constraints. The bus may link various circuits including a processor, a machine-readable medium, and a bus interface to each other. The bus interface may be used to connect a network adapter, in particular, to the processing system via the bus. The network adapter may be used to implement the signal processing functions of the PHY layer. In the case of the user terminal 120 (see FIG. 1), a user interface (e.g., keypad, display, mouse, joystick, etc.) may also be connected to the bus. The bus may also link various other circuits such as a timing source, peripherals, a voltage regulator, a power management circuit, etc., which are well known in the art and thus will not be described further. The processor may be implemented using one or more general-purpose processors and / or dedicated processors. Examples include a microprocessor, a microcontroller, a DSP processor, and other circuits capable of executing software. Those skilled in the art will recognize how best to implement the described functions for the processing system depending on the specific application and overall design constraints imposed on the overall system.

[0182]

[0192] When implemented in software, the functions can be stored on a computer-readable medium as one or more instructions or code, or can be transmitted via a computer-readable medium. Software is to be broadly construed to mean instructions, data, or any combination thereof, regardless of the name given to it, such as software, firmware, middleware, microcode, hardware description language, etc. A computer-readable medium includes both computer storage media and communication media, including any medium that can enable the transfer of a computer program from one location to another. A processor may be responsible for managing buses and general processing, including the execution of software modules stored on a machine-readable storage medium. A computer-readable storage medium can be coupled to the processor such that the processor can read information from, and write information to, the storage medium. Alternatively, the storage medium can be integrated into the processor. By way of example, a machine-readable medium can include transmission lines, a carrier wave modulated by data, and / or a computer-readable storage medium having instructions stored thereon that are separate from a wireless node and that can all be accessed by a processor via a bus interface. Alternatively, or in addition, a machine-readable medium or any portion thereof can be integrated into the processor, as a cache and / or a general-purpose register file might be. Examples of machine-readable storage media can include, by way of example, RAM (Random Access Memory), flash memory, ROM (Read Only Memory), PROM (Programmable Read Only Memory), EPROM (Erasable Programmable Read Only Memory), EEPROM (registered trademark) (Electrically Erasable Programmable Read Only Memory), registers, magnetic disks, optical disks, hard drives, or any other suitable storage medium, or any combination thereof. A machine-readable medium can be implemented in a computer program product.

[0183]

[0193] A software module can comprise a single instruction or multiple instructions and can be distributed over several different code segments, between different programs, and across multiple storage media. A computer-readable medium can comprise several software modules. A software module contains instructions that, when executed by an apparatus such as a processor, cause a processing system to perform various functions. A software module can include a transmitting module and a receiving module. Each software module can reside in a single storage device or can be distributed across multiple storage devices. As an example, when a trigger event occurs, a software module can be loaded from a hard drive into RAM. During execution of a software module, the processor can load some of the instructions into a cache to increase access speed. Then, one or more cache lines can be loaded into a general-purpose register file for execution by the processor. When referring hereinafter to the functions of a software module, it will be understood that such functions are implemented by the processor when executing instructions from that software module.

[0184]

[0194] Also, any connection is properly termed a computer-readable medium. For example, when software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared (IR), radio, and microwave, the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of the medium. As used herein, disk and disc include compact disc (CD), laser disc (registered trademark), optical disc, digital versatile disc (DVD), floppy (registered trademark) disk, and Blu-ray (registered trademark) disc, where disk typically magnetically reproduces data and disc optically reproduces data with a laser. Thus, in some embodiments, a computer-readable medium may comprise a non-transitory computer-readable medium (e.g., a tangible medium). Further, in other embodiments, a computer-readable medium may comprise a transitory computer-readable medium (e.g., a signal). The above combinations should also be included within the scope of computer-readable media.

[0185]

[0195] Thus, some embodiments may comprise a computer program product for performing the operations presented herein. For example, such a computer program product may comprise a computer-readable medium having (and / or encoded with) instructions executable by one or more processors to perform the operations described herein. For example, instructions for performing the operations described herein and shown in FIGS. 7 and / or 8.

[0186]

[0196] Furthermore, it should be understood that modules and / or other suitable means for performing the methods and techniques described herein may be downloaded by a user terminal and / or a base station, and / or obtained in other ways, where applicable. For example, such devices may be coupled to a server to enable transfer of means for performing the methods described herein. Alternatively, the various methods described herein may be provided by a storage means such that a user terminal and / or a base station can obtain the various methods when the storage means (such as a physical storage medium such as RAM, ROM, compact disk (CD) or floppy disk) is coupled to or provided to the device. Moreover, any other suitable technique for providing the methods and techniques described herein to a device may be utilized.

[0187]

[0197] It should be understood that the claims are not limited to the exact construction and components shown above. Various modifications, changes, and variations can be made in the construction, operation, and details of the methods and apparatuses described above without departing from the scope of the claims.

Claims

1. 1. A method for wireless communication by a user equipment (UE), comprising: receiving, from a network entity, a channel state information (CSI) reporting configuration indicating at least first and second CSI reference signal (CSI-RS) resource or port groups associated with a CSI report; performing CSI measurements based on a frequency division multiplexing (FDM) scheme comprising transmissions over a first resource or port group on a first set of FD units and transmissions over a second resource or port group on a second set of FD units; transmitting to the network entity a PMI report indicating a first set of one or more Precoding Matrix Indicators (PMIs) associated with the ports in the first resource or port group on a first set of FD units and a second set of one or more PMIs associated with the ports in the second resource or port group on a second set of FD units; A method comprising:

2. The method of claim 1 , wherein the FD unit comprises a subband or a PRG.

3. The method of claim 2 , further comprising receiving a configuration indicating the FDM scheme.

4. selecting an FDM scheme from a set of candidate schemes; reporting the selected FDM scheme to the network entity; The method of claim 2 , further comprising:

5. 2. The method of claim 1, further comprising receiving an indication of frequency domain resource allocation (FDRA) indicating whether the first and second sets of FD units are interleaved or span contiguous sets of FD units.

6. The method of claim 5 , wherein the indication is provided via the CSI reporting configuration or via a Precoding Block Resource Group (PRG) or subband group indicator.

7. 7. The method of claim 6, wherein the configuration comprises a joint configuration of an FDM scheme for CSI measurements and the FDRA of the first set of FD units for the first resource or port group and the FDRA of the first set of FD units for the first resource or port group second set of FD units.

8. 2. The method of claim 1, further comprising determining whether the first and second sets of FD units are interleaved or span contiguous sets of FD units based on an actual CSI-RS transmission.

9. selecting a candidate frequency division resource allocation FDRA for the first and second sets of FD units from a set of candidate FDRAs; reporting the selected FDRA to the network entity; The method of claim 1 further comprising:

10. The method of claim 9 , wherein the report indicates an FDM scheme from a set of candidate schemes selected by the UE together with its FDRA.

11. a total number of precoding matrices reported in the first set of PMIs is determined based at least in part on a number of subbands in the first set of FD units; 2. The method of claim 1, wherein a total number of precoding matrices reported in the second set of PMIs is determined based at least in part on a number of subbands in the second set of FD units.

12. When a certain type of CSI is applied to either the first set of PMIs or the second set of PMIs, the number of reported precoding matrices is a function of the number of subbands in the corresponding set of FD units and configured parameters. The method of claim 1.

13. 1. A method for wireless communication by a user equipment (UE), comprising: determining a transmission scheme for a channel state information (CSI) reference signal (CSI-RS) resource or port group using at least a first and a second CSI-RS resource or port group; performing CSI measurements based on CSI-RS transmissions sent over at least a first and a second CSI-RS resource or port group; transmitting to the network entity a PMI report indicating a first set of one or more Precoding Matrix Indicators (PMIs) associated with the first resource or port group, a second set of one or more PMIs associated with the second resource or port group, a first Layer Indicator (LI) associated with the first set of PMIs, and a second LI associated with the second set of PMIs; A method comprising:

14. The method of claim 13 , wherein the transmission scheme comprises spatial division multiplexing (SDM).

15. The method of claim 13 , wherein the transmission scheme comprises time division multiplexing (TDM).

16. The method of claim 13 , wherein the transmission scheme comprises frequency division multiplexing (FDM).

17. The first CSI measurement is performed based on the first CSI-RS resource or port group received on a first set of frequency domain (FD) units; the second CSI measurement is performed based on the second CSI-RS resource or port group received on a second set of FD units.

17. The method of claim 16.

18. The first LI indicates a strongest layer among the layers indicated by the first set of PMIs; The second LI indicates the strongest layer among the layers indicated by the second set of PMIs. The method of claim 13.

19. 1. A method for wireless communication by a user equipment (UE), comprising: receiving a channel state information (CSI) reporting configuration from a network entity, the configuration indicating at least one CSI reference signal (CSI-RS) resource comprising at least first and second CSI-RS port groups; determining a CSI codebook associated with each CSI-RS port for precoding matrix indicator (PMI) and channel quality indicator (CQI) measurements; performing PMI and CQI measurement using the determined CSI codebook, using CSI-RS port indices in respective CSI-RS port groups, and reporting a first PMI mapped to a port index in the first group and a second PMI mapped to a port index in the second group; A method comprising:

20. 20. The method of claim 19, wherein the CQI measurement depends at least in part on a transmission scheme used for the CSI RS report.

21. 21. The method of claim 20, wherein if the transmission scheme comprises a spatial division multiplexing (SDM) scheme, the UE assumes a physical downlink shared channel (PDSCH) and calculates a CQI based on a first mapping from a first set of layers to the first port group with a first index via the first precoding matrix indicated via a first PMI and a second mapping from a second set of layers to the second port group with a second index via a second precoding matrix indicated via the second PMI.

22. If the transmission scheme comprises a frequency division multiplexing (FDM) scheme, the UE the first PMI that maps a first layer to the first port group on a first set of frequency domain (FD) units; the second PMI mapping a second layer to the second port group on a second set of FD units; 21. The method of claim 20, further comprising: assuming a physical downlink shared channel (PDSCH) and calculating the CQI based on:

23. If the transmission scheme comprises a time division multiplexing (TDM) scheme, the UE the first PMI that maps a first layer to the first port group on a first set of time domain (TD) units; the second PMI mapping a second layer to the second port group on a second set of TD units; 21. The method of claim 20, further comprising: assuming a physical downlink shared channel (PDSCH) and calculating the CQI based on:

24. 1. A method for wireless communication by a network entity, comprising: transmitting, to a user equipment (UE), a CSI reporting configuration indicating at least first and second CSI reference signal (CSI-RS) resource or port groups associated with a channel state information (CSI) report; transmitting the CSI-RS based on a frequency division multiplexing (FDM) scheme comprising transmission over a first resource or port group on a first set of FD units and transmission over a second resource or port group on a second set of FD units; receiving from the UE a precoding matrix indicator (PMI) report indicating a first set of one or more PMIs associated with the ports in the first resource or port group on a first set of FD units and a second set of one or more PMIs associated with the ports in the second resource or port group on a second set of FD units; A method comprising:

25. The method of claim 24 , wherein the FD unit comprises a subband or a PRG.

26. 26. The method of claim 25, further comprising transmitting a configuration to the UE indicating the FDM scheme.

27. sending a set of candidate schemes to the UE; receiving, from the UE, a report indicating a FDM scheme selected from the set of candidate schemes; 26. The method of claim 25, further comprising:

28. 25. The method of claim 24, further comprising providing to the UE an indication of frequency domain resource allocation (FDRA) indicating whether the first and second sets of FD units are interleaved or span contiguous sets of FD units.

29. 30. The method of claim 28, wherein the indication is provided via the CSI reporting configuration or via a Precoding Block Resource Group (PRG) or subband group indicator.

30. 30. The method of claim 29, wherein the configuration comprises a joint configuration of an FDM scheme for CSI measurements and the FDRA of the first set of FD units for the first resource or port group and the FDRA of the first set of FD units for the first resource or port group second set of FD units.

31. sending a set of candidate frequency domain resource allocations (FDRAs) to the UE; receiving, from the UE, an indication of an FDRA selected from the set of candidate FDRAs; 25. The method of claim 24, further comprising:

32. The method of claim 31 , wherein the indication indicates an FDM scheme from a set of candidate schemes selected by the UE together with its FDRA.

33. a total number of precoding matrices reported in the first set of PMIs is determined based at least in part on a number of subbands in the first set of FD units; a total number of precoding matrices reported in the second set of PMIs is determined based at least in part on a number of subbands in the second set of FD units.

25. The method of claim 24.

34. When a certain type of CSI is applied to either the first set of PMIs or the second set of PMIs, the number of reported precoding matrices is a function of the number of subbands in the corresponding set of FD units and configured parameters.

25. The method of claim 24.

35. 1. A method for wireless communication by a network entity, comprising: transmitting a channel state information (CSI) reference signal (CSI-RS) to a user equipment (UE) according to a transmission scheme using at least first and second CSI reference signal (RS) resource or port groups; receiving from the UE a PMI report indicating a first set of one or more Precoding Matrix Indicators (PMIs) associated with the first resource or port group, a second set of one or more PMIs associated with the second resource or port group, a first Layer Indicator (LI) associated with the first set of PMIs, and a second LI associated with the second set of PMIs; A method comprising:

36. 36. The method of claim 35, wherein the transmission scheme comprises spatial division multiplexing (SDM).

37. 36. The method of claim 35, wherein the transmission scheme comprises time division multiplexing (TDM).

38. 36. The method of claim 35, wherein the transmission scheme comprises frequency division multiplexing (FDM).

39. The first LI indicates a strongest layer among the layers indicated by the first set of PMIs; The second LI indicates the strongest layer among the layers indicated by the second set of PMIs.

36. The method of claim 35.

40. 1. A method for wireless communication by a network entity, comprising: transmitting, to a user equipment (UE), a channel state information (CSI) reference signal (CSI-RS) reporting configuration indicating at least one CSI-RS resource comprising at least first and second CSI-RS port groups; determining a CSI codebook associated with each CSI-RS port for precoding matrix indicator (PMI) and channel quality indicator (CQI) measurements; receiving, from the UE, a report of a first PMI mapped to a port index in the first group and a second PMI mapped to a port index in the second group based on PMI and CQI measurements made by the UE using the determined CSI codebook using a CSI-RS port index in a respective CSI-RS port group; A method comprising:

41. 41. The method of claim 40, wherein the CQI measurement depends at least in part on a transmission scheme used for the CSI RS report.

42. 42. The method of claim 41, wherein if the transmission scheme comprises a spatial division multiplexing (SDM) scheme, the UE assumes a physical downlink shared channel (PDSCH) and calculates a CQI based on a first mapping from a first set of layers to a first port group with a first index via the first precoding matrix indicated via a first PMI and a second mapping from a second set of layers to the second port group with a second index via a second precoding matrix indicated via the second PMI.

43. If the transmission scheme comprises a frequency division multiplexing (FDM) scheme, the UE the first PMI that maps a first layer to the first port group on a first set of frequency domain (FD) units; the second PMI mapping a second layer to the second port group on a second set of FD units; 42. The method of claim 41, further comprising: assuming a physical downlink shared channel (PDSCH) and calculating the CQI based on:

44. If the transmission scheme comprises a time division multiplexing (TDM) scheme, the UE the first PMI that maps a first layer to the first port group on a first set of time domain (TD) units; the second PMI mapping a second layer to the second port group on a second set of TD units; 42. The method of claim 41, further comprising: assuming a physical downlink shared channel (PDSCH) and calculating the CQI based on:

45. An apparatus for wireless communication by a user equipment (UE), comprising: At least one processor and a memory, the at least one processor and the memory receiving, from a network entity, a channel state information (CSI) reporting configuration indicating at least first and second CSI reference signal (CSI-RS) resource or port groups associated with a CSI report; performing CSI measurements based on a frequency division multiplexing (FDM) scheme comprising transmissions over a first resource or port group on a first set of FD units and transmissions over a second resource or port group on a second set of FD units; transmitting to the network entity a PMI report indicating a first set of one or more Precoding Matrix Indicators (PMIs) associated with the ports in the first resource or port group on a first set of FD units and a second set of one or more PMIs associated with the ports in the second resource or port group on a second set of FD units; configured to: Device.

46. The apparatus of claim 45 , wherein the FD unit comprises a subband or a PRG.

47. 47. The apparatus of claim 46, wherein the at least one processor and the memory are further configured to receive a configuration indicative of the FDM scheme.

48. The at least one processor and the memory include: selecting an FDM scheme from a set of candidate schemes; reporting the selected FDM scheme to the network entity; 47. The apparatus of claim 46, further configured to:

49. 46. ​​The apparatus of claim 45, wherein the at least one processor and the memory are further configured to receive an indication of frequency domain resource allocation (FDRA) indicating whether the first and second sets of FD units are interleaved or span contiguous sets of FD units.

50. 50. The apparatus of claim 49, wherein the indication is provided via the CSI reporting configuration or via a precoding block resource group (PRG) or subband group indicator.

51. 51. The apparatus of claim 50, wherein the configuration comprises a joint configuration of an FDM scheme for CSI measurements and the FDRA of the first set of FD units for the first resource or port group and the FDRA of the first set of FD units for the first resource or port group second set of FD units.

52. 46. ​​The apparatus of claim 45, wherein the at least one processor and the memory are further configured to determine, based on an actual CSI-RS transmission, whether the first and second sets of FD units are interleaved or span contiguous sets of FD units.

53. The at least one processor and the memory include: selecting a candidate frequency division resource allocation FDRA for the first and second sets of FD units from a set of candidate FDRAs; reporting the selected FDRA to the network entity; 46. ​​The apparatus of claim 45, further configured to:

54. 54. The apparatus of claim 53, wherein the report indicates an FDM scheme from a set of candidate schemes selected by the UE together with its FDRA.

55. a total number of precoding matrices reported in the first set of PMIs is determined based at least in part on a number of subbands in the first set of FD units; a total number of precoding matrices reported in the second set of PMIs is determined based at least in part on a number of subbands in the second set of FD units.

46. ​​The apparatus of claim 45.

56. When a certain type of CSI is applied to either the first set of PMIs or the second set of PMIs, the number of reported precoding matrices is a function of the number of subbands in the corresponding set of FD units and configured parameters.

46. ​​The apparatus of claim 45.

57. An apparatus for wireless communication by a user equipment (UE), comprising: At least one processor and a memory, the at least one processor and the memory determining a transmission scheme for a channel state information (CSI) reference signal (CSI-RS) resource or port group using at least a first and a second CSI-RS resource or port group; performing CSI measurements based on CSI-RS transmissions sent over at least a first and a second CSI-RS resource or port group; transmitting to the network entity a PMI report indicating a first set of one or more Precoding Matrix Indicators (PMIs) associated with the first resource or port group, a second set of one or more PMIs associated with the second resource or port group, a first Layer Indicator (LI) associated with the first set of PMIs, and a second LI associated with the second set of PMIs; configured to: Device.

58. 60. The apparatus of claim 57, wherein the transmission scheme comprises spatial division multiplexing (SDM).

59. 58. The apparatus of claim 57, wherein the transmission scheme comprises time division multiplexing (TDM).

60. 58. The apparatus of claim 57, wherein the transmission scheme comprises frequency division multiplexing (FDM).

61. The first CSI measurement is performed based on the first CSI-RS resource or port group received on a first set of frequency domain (FD) units; the second CSI measurement is performed based on the second CSI-RS resource or port group received on a second set of FD units.

61. The apparatus of claim 60.

62. The first LI indicates a strongest layer among the layers indicated by the first set of PMIs; The second LI indicates the strongest layer among the layers indicated by the second set of PMIs.

58. The apparatus of claim 57.

63. An apparatus for wireless communication by a user equipment (UE), comprising: At least one processor and a memory, the at least one processor and the memory receiving a channel state information (CSI) reporting configuration from a network entity, the configuration indicating at least one CSI reference signal (CSI-RS) resource comprising at least first and second CSI-RS port groups; determining a CSI codebook associated with each CSI-RS port for precoding matrix indicator (PMI) and channel quality indicator (CQI) measurements; performing PMI and CQI measurement using the determined CSI codebook, using CSI-RS port indices in respective CSI-RS port groups, and reporting a first PMI mapped to a port index in the first group and a second PMI mapped to a port index in the second group; configured to: Device.

64. 64. The apparatus of claim 63, wherein the CQI measurement depends at least in part on a transmission scheme used for the CSI RS report.

65. 65. The apparatus of claim 64, wherein if the transmission scheme comprises a spatial division multiplexing (SDM) scheme, the UE assumes a physical downlink shared channel (PDSCH) and calculates a CQI based on a first mapping from a first set of layers to a first port group with a first index via the first precoding matrix indicated via a first PMI and a second mapping from a second set of layers to the second port group with a second index via a second precoding matrix indicated via the second PMI.

66. If the transmission scheme comprises a frequency division multiplexing (FDM) scheme, the UE the first PMI that maps a first layer to the first port group on a first set of frequency domain (FD) units; the second PMI mapping a second layer to the second port group on a second set of FD units; 65. The apparatus of claim 64, further comprising: calculating a CQI assuming a physical downlink shared channel (PDSCH) based on:

67. If the transmission scheme comprises a time division multiplexing (TDM) scheme, the UE the first PMI that maps a first layer to the first port group on a first set of time domain (TD) units; the second PMI mapping a second layer to the second port group on a second set of TD units; 65. The apparatus of claim 64, further comprising: calculating a CQI assuming a physical downlink shared channel (PDSCH) based on:

68. An apparatus for wireless communication by a network entity, comprising: at least one processor and a memory, the at least one processor and the memory comprising: transmitting, to a user equipment (UE), a CSI reporting configuration indicating at least first and second CSI reference signal (CSI-RS) resource or port groups associated with a channel state information (CSI) report; transmitting the CSI-RS based on a frequency division multiplexing (FDM) scheme comprising transmission over a first resource or port group on a first set of FD units and transmission over a second resource or port group on a second set of FD units; receiving from the UE a precoding matrix indicator (PMI) report indicating a first set of one or more PMIs associated with the ports in the first resource or port group on a first set of FD units and a second set of one or more PMIs associated with the ports in the second resource or port group on a second set of FD units; configured to: Device.

69. 70. The apparatus of claim 68, wherein the FD unit comprises a subband or a PRG.

70. 70. The apparatus of claim 69, wherein the at least one processor and the memory are further configured to: transmit, to the UE, a configuration indicating the FDM scheme.

71. The at least one processor and the memory include: sending a set of candidate schemes to the UE; receiving, from the UE, a report indicating a FDM scheme selected from the set of candidate schemes; 70. The apparatus of claim 69, further configured to:

72. 69. The apparatus of claim 68, wherein the at least one processor and the memory are further configured to: provide to the UE an indication of frequency domain resource allocation (FDRA) indicating whether the first and second sets of FD units are interleaved or span contiguous sets of FD units.

73. 73. The apparatus of claim 72, wherein the indication is provided via the CSI reporting configuration or via a precoding block resource group (PRG) or subband group indicator.

74. 74. The apparatus of claim 73, wherein the configuration comprises a joint configuration of an FDM scheme for CSI measurements and the FDRA of the first set of FD units for the first resource or port group and the FDRA of the first set of FD units for the first resource or port group second set of FD units.

75. The at least one processor and the memory include: sending a set of candidate frequency domain resource allocations (FDRAs) to the UE; receiving, from the UE, an indication of an FDRA selected from the set of candidate FDRAs; 69. The apparatus of claim 68, further configured to:

76. 76. The apparatus of claim 75, wherein the indication indicates an FDM scheme from a set of candidate schemes selected by the UE together with its FDRA.

77. a total number of precoding matrices reported in the first set of PMIs is determined based at least in part on a number of subbands in the first set of FD units; a total number of precoding matrices reported in the second set of PMIs is determined based at least in part on a number of subbands in the second set of FD units.

69. The apparatus of claim 68.

78. When a certain type of CSI is applied to either the first set of PMIs or the second set of PMIs, the number of reported precoding matrices is a function of the number of subbands in the corresponding set of FD units and configured parameters.

69. The apparatus of claim 68.

79. An apparatus for wireless communication by a network entity, comprising: At least one processor and a memory, the at least one processor and the memory transmitting a channel state information (CSI) reference signal (CSI-RS) to a user equipment (UE) according to a transmission scheme using at least first and second CSI reference signal (RS) resource or port groups; receiving from the UE a PMI report indicating a first set of one or more Precoding Matrix Indicators (PMIs) associated with the first resource or port group, a second set of one or more PMIs associated with the second resource or port group, a first Layer Indicator (LI) associated with the first set of PMIs, and a second LI associated with the second set of PMIs; configured to: Device.

80. 80. The apparatus of claim 79, wherein the transmission scheme comprises spatial division multiplexing (SDM).

81. 80. The apparatus of claim 79, wherein the transmission scheme comprises time division multiplexing (TDM).

82. 80. The apparatus of claim 79, wherein the transmission scheme comprises frequency division multiplexing (FDM).

83. The first LI indicates a strongest layer among the layers indicated by the first set of PMIs; The second LI indicates the strongest layer among the layers indicated by the second set of PMIs.

80. The apparatus of claim 79.

84. An apparatus for wireless communication by a network entity, comprising: At least one processor and a memory, the at least one processor and the memory transmitting, to a user equipment (UE), a channel state information (CSI) reference signal (CSI-RS) reporting configuration indicating at least one CSI-RS resource comprising at least first and second CSI-RS port groups; determining a CSI codebook associated with each CSI-RS port for precoding matrix indicator (PMI) and channel quality indicator (CQI) measurements; receiving, from the UE, a report of a first PMI mapped to a port index in the first group and a second PMI mapped to a port index in the second group based on PMI and CQI measurements made by the UE using the determined CSI codebook using a CSI-RS port index in a respective CSI-RS port group; configured to: Device.

85. 85. The apparatus of claim 84, wherein the CQI measurement depends at least in part on a transmission scheme used for the CSI RS report.

86. 86. The apparatus of claim 85, wherein if the transmission scheme comprises a spatial division multiplexing (SDM) scheme, the UE assumes a physical downlink shared channel (PDSCH) and calculates a CQI based on a first mapping from a first set of layers to a first port group with a first index via the first precoding matrix indicated via a first PMI and a second mapping from a second set of layers to the second port group with a second index via a second precoding matrix indicated via the second PMI.

87. If the transmission scheme comprises a frequency division multiplexing (FDM) scheme, the UE the first PMI that maps a first layer to the first port group on a first set of frequency domain (FD) units; the second PMI mapping a second layer to the second port group on a second set of FD units; 86. The apparatus of claim 85, further comprising: calculating a CQI assuming a physical downlink shared channel (PDSCH) based on:

88. If the transmission scheme comprises a time division multiplexing (TDM) scheme, the UE the first PMI that maps a first layer to the first port group on a first set of time domain (TD) units; the second PMI mapping a second layer to the second port group on a second set of TD units; 86. The apparatus of claim 85, further comprising: calculating a CQI assuming a physical downlink shared channel (PDSCH) based on:

89. An apparatus for wireless communication by a user equipment (UE), comprising: means for receiving, from a network entity, a channel state information (CSI) reporting configuration indicating at least first and second CSI reference signal (CSI-RS) resource or port groups associated with a CSI report; means for performing CSI measurements based on a Frequency Division Multiplexing (FDM) scheme comprising transmissions over a first resource or port group on a first set of FD units and transmissions over a second resource or port group on a second set of FD units; means for transmitting to the network entity a PMI report indicating a first set of one or more Precoding Matrix Indicators (PMIs) associated with the ports in the first resource or port group on a first set of FD units and a second set of one or more PMIs associated with the ports in the second resource or port group on a second set of FD units; An apparatus comprising:

90. An apparatus for wireless communication by a user equipment (UE), comprising: means for determining a transmission scheme for a channel state information (CSI) report using at least a first and a second CSI reference signal (CSI-RS) resource or port group; means for performing CSI measurements based on CSI-RS transmissions sent over at least a first and a second CSI-RS resource or port group; means for transmitting to the network entity a PMI report indicating a first set of one or more Precoding Matrix Indicators (PMIs) associated with the first resource or port group, a second set of one or more PMIs associated with the second resource or port group, a first Layer Indicator (LI) associated with the first set of PMIs, and a second LI associated with the second set of PMIs; An apparatus comprising:

91. An apparatus for wireless communication by a user equipment (UE), comprising: means for receiving a channel state information (CSI) reporting configuration from a network entity, the configuration indicating at least one CSI reference signal (CSI-RS) resource comprising at least first and second CSI-RS port groups; means for determining a CSI codebook associated with each CSI-RS port for precoding matrix indicator (PMI) and channel quality indicator (CQI) measurements; means for performing PMI and CQI measurement by using the determined CSI codebook, using CSI-RS port indices in respective CSI-RS port groups, and reporting a first PMI mapped to a port index in the first group and a second PMI mapped to a port index in the second group; An apparatus comprising:

92. An apparatus for wireless communication by a network entity, comprising: means for transmitting, to a user equipment (UE), a channel state information (CSI) reporting configuration indicating at least first and second CSI reference signal (CSI-RS) resource or port groups associated with a CSI report; means for transmitting CSI-RS based on a Frequency Division Multiplexing (FDM) scheme comprising transmission over a first resource or port group on a first set of FD units and transmission over a second resource or port group on a second set of FD units; means for receiving, from the UE, a precoding matrix indicator (PMI) report indicating a first set of one or more PMIs associated with the ports in the first resource or port group on a first set of FD units and a second set of one or more PMIs associated with the ports in the second resource or port group on a second set of FD units; An apparatus comprising:

93. An apparatus for wireless communication by a network entity, comprising: means for transmitting a channel state information (CSI) reference signal (CSI-RS) to a user equipment (UE) according to a transmission scheme using at least first and second CSI reference signal (RS) resource or port groups; means for receiving, from the UE, a PMI report indicating a first set of one or more Precoding Matrix Indicators (PMIs) associated with the first resource or port group, a second set of one or more PMIs associated with the second resource or port group, a first Layer Indicator (LI) associated with the first set of PMIs, and a second LI associated with the second set of PMIs; An apparatus comprising:

94. An apparatus for wireless communication by a network entity, comprising: means for transmitting, to a user equipment (UE), a channel state information (CSI) reference signal (CSI-RS) reporting configuration indicating at least one CSI-RS resource comprising at least first and second CSI-RS port groups; means for determining a CSI codebook associated with each CSI-RS port for precoding matrix indicator (PMI) and channel quality indicator (CQI) measurements; means for receiving, from the UE, a report of a first PMI mapped to a port index in the first group and a second PMI mapped to a port index in the second group based on PMI and CQI measurements made by the UE using the determined CSI codebook using a CSI-RS port index in a respective CSI-RS port group; An apparatus comprising:

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