Robustness considerations for 2-stage DCI for uplink subband precoding for frequency domain compression

Abstract

Certain aspects of the present disclosure provide techniques for using subband precoding for uplink transmissions. In some cases, a UE can receive, from a network entity, at least one of a first downlink control information (DCI) or a second DCI, each DCI indicating at least one of one or more sets containing one or more frequency domain (FD) bases and linear combination coefficients; and transmit a PUSCH with subband precoding determined based on the first DCI, the second DCI, or a combination of the first and second DCIs, depending on whether the first DCI is received, the second DCI is received, or both the first and second DCIs are received.

Description

[0001] background

[0002] open field

[0003] Various aspects of this disclosure relate to wireless communication, and more particularly to techniques for performing subband-level precoding for uplink transmission.

[0004] Related technical descriptions

[0005] Wireless communication systems are widely deployed to provide a variety of telecommunications services such as telephone, video, data, messaging, and broadcasting. These wireless communication systems can employ multiple access technologies that enable communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). Examples of such multiple access systems include 3GPP Long Term Evolution (LTE) systems, LTE-A Advanced systems, Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, Orthogonal Frequency Division Multiple Access (OFDMA) systems, Single Carrier Frequency Division Multiple Access (SC-FDMA) systems, and Time Division Synchronous Code Division Multiple Access (TD-SCDMA) systems, to name just a few.

[0006] In some examples, a radio multiple access communication system may include several base stations (BSs), each capable of simultaneously supporting communication from multiple communication devices (also referred to as user equipment (UE)). In LTE or LTE-A networks, a set containing one or more base stations may define an evolved B-node (eNB). In other examples (e.g., in next-generation, new radio (NR), or 5G networks), a radio multiple access communication system may include several distributed units (DUs) (e.g., edge units (EUs), edge nodes (ENs), radio heads (RHs), smart radio heads (SRHs), transmit-receive points (TRPs), etc.) communicating with several central units (CUs) (e.g., central nodes (CNs), access node controllers (ANCs), etc.), and a set containing one or more DUs communicating with the CUs may define an access node (e.g., which may be referred to as a BS, 5G NB, next-generation B-node (gNB or gNodeB), transmit-receive point (TRP), etc.). The BS or DU can communicate with the UE set on both downlink channels (e.g., for transmissions from the BS or DU to the UE) and uplink channels (e.g., for transmissions from the UE to the BS or DU).

[0007] These multiple access technologies have been adopted in various telecommunications standards to provide a common protocol enabling different wireless devices to communicate at the city, country, region, and even global levels. NR (e.g., New Radio or 5G) is an example of an emerging telecommunications standard. NR is an enhancement set of the LTE mobile standard issued by 3GPP. NR is designed to better support mobile broadband Internet access by improving spectrum efficiency, reducing costs, improving service, utilizing new spectrum, and better integrating with other open standards using OFDMA with cyclic prefix (CP) on both the downlink (DL) and uplink (UL). To this end, NR supports beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation.

[0008] However, with the continued growth in demand for mobile broadband access, there is a need for further improvements to NR and LTE technologies. Preferably, these improvements should be applicable to other multiple access technologies and telecommunications standards that employ these technologies.

[0009] Overview

[0010] The systems, methods, and apparatus of this disclosure each have several aspects, and their desired properties are not solely attributed to any single aspect. Without limiting the scope of this disclosure as set forth in the appended claims, some features will now be briefly discussed. Upon consideration of this discussion, and especially after reading the section entitled "Detailed Description," it will be understood how the features of this disclosure provide advantages including improved communication between access points and stations in a wireless network.

[0011] Some aspects of the disclosure relate to a method for wireless communication by a user equipment (UE). The method generally includes: receiving at least one of a first downlink control information (DCI) or a second DCI from a network entity, each DCI indicating at least one set of one or more sets containing one or more frequency domain (FD) bases and linear combination coefficients; determining subband precoding based on the first DCI, the second DCI, or a combination of the first and second DCIs, depending on whether the first DCI, the second DCI, or both are received; and transmitting the Physical Uplink Shared Channel (PUSCH) via the subband precoding.

[0012] Certain aspects of this disclosure relate to a method for wireless communication by a network entity. The method generally includes: transmitting at least a first downlink control information (DCI) and a second DCI to a user equipment (UE), each DCI indicating at least one set of one or more sets containing one or more frequency domain (FD) bases and linear combination coefficients; and processing a Physical Uplink Shared Channel (PUSCH) transmitted from the UE via subband precoding based on the first DCI, the second DCI, or a combination of the first DCI and the second DCI.

[0013] Various apparatuses, devices, and computer-readable media are also provided in this disclosure for performing the operations described herein.

[0014] To achieve the foregoing and related objectives, these one or more aspects include the features fully described below and specifically pointed out in the claims. Certain illustrative features of these one or more aspects are set forth in detail in the following description and drawings. However, these features merely indicate a few of the various ways in which the principles of these aspects may be employed. Brief description of the attached diagram

[0016] To gain a more detailed understanding of the features described above in this disclosure, reference can be made to a more specific description of the above-briefly summarized aspects, some of which are illustrated in the accompanying drawings. However, it should be noted that the drawings illustrate only certain typical aspects of this disclosure and should not be considered as limiting its scope, as other equivalent aspects are permissible in this description.

[0017] Figure 1 It is a block diagram that conceptually illustrates certain aspects of an example telecommunications system according to this disclosure.

[0018] Figure 2 This is a block diagram illustrating an example of a communication protocol stack for implementing an example RAN architecture according to certain aspects of this disclosure.

[0019] Figure 3 It is a block diagram that conceptually illustrates the design of an example base station (BS) and user equipment (UE) according to certain aspects of this disclosure.

[0020] Figure 4 Examples of frame formats for telecommunications systems according to certain aspects of this disclosure are explained.

[0021] Figure 5 Conceptual examples of a first precoder matrix for transport layer 0 and a second precoder matrix for transport layer 1, according to certain aspects of this disclosure, are explained.

[0022] Figure 6 Three tables illustrating example M values ​​according to rank and hierarchy are explained according to certain aspects of this disclosure.

[0023] Figure 7 Various matrices are explained graphically.

[0024] Figure 8 This is a call flowchart illustrating an example of codebook-based UL transmission.

[0025] Figure 9 An example of wideband precoding for codebook-based UL transmission is explained.

[0026] Figure 10 This is a call flow diagram illustrating an example of non-codebook-based UL transmission.

[0027] Figure 11 An example of wideband precoding for non-codebook-based UL transmission is explained.

[0028] Figure 12A-12F The precoder matrix set used for various layer and antenna port combinations is explained.

[0029] Figure 13 This is a call flow diagram illustrating an example UL transmission with sub-band precoding according to certain aspects of this disclosure.

[0030] Figure 14 Example linear combinations of FD bases according to various aspects of this disclosure are explained.

[0031] Figures 15A-15D Example scenarios for FD basis and linear combination coefficients according to various aspects of this disclosure are explained.

[0032] Figure 16 Example operations for wireless communication by a UE according to certain aspects of this disclosure are explained.

[0033] Figure 17 Example operations for wireless communication by a base station according to certain aspects of this disclosure are explained.

[0034] Figure 18 Examples of UL subband precoding based on one or more DCIs according to various aspects of this disclosure are explained.

[0035] To facilitate understanding, the same reference numerals are used wherever possible to designate common elements shared by all figures. Elements disclosed in one aspect are conceived to be usefully applied in other aspects without specific citation.

[0036] Detailed description

[0037] Various aspects of this disclosure relate to wireless communication, and more particularly to techniques for performing subband-level precoding for uplink transmission.

[0038] The following description provides examples and is not intended to limit the scope, applicability, or examples set forth in the claims. Changes may be made to the function and arrangement of the elements discussed without departing from the scope of this disclosure. Various procedures or components may be appropriately omitted, substituted, or added to the examples. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Moreover, features described with reference to some examples may be combined in others. For example, any number of aspects set forth herein may be used to implement an apparatus or practice. Furthermore, the scope of this disclosure is intended to cover such apparatuses or methods practiced using additional structures, functionalities, or structures and functionalities that complement or supplement the various aspects of this disclosure set forth herein. It should be understood that any aspect of this disclosure disclosed herein may be implemented by one or more elements of the claims. The term “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any aspect described herein as “exemplary” is not necessarily to be construed as superior to or overriding other aspects.

[0039] The technologies described in this document can be used in 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. CDMA networks can implement radio technologies such as Universal Terrestrial Radio Access (UTRA) and cdma2000. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. cdma2000 covers the IS-2000, IS-95, and IS-856 standards. TDMA networks can implement radio technologies such as Global System for Mobile Communications (GSM). OFDMA networks can implement radio technologies such as NR (e.g., 5G RA), Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, and Flash-OFDMA. UTRA and E-UTRA are part of the Universal Mobile Telecommunications System (UMTS).

[0040] New Radio (NR) is an emerging wireless communication technology being developed in collaboration with the 5G Technology Forum (5GTF). 3GPP Long Term Evolution (LTE) and LTE-Advanced (LTE-A) are versions of UMTS using E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, and GSM are described in documents from an organization called the Third Generation Partnership Project (3GPP). cdma2000 and UMB are described in documents from an organization called the Third Generation Partnership Project 2 (3GPP2). The technologies described herein can be used with the aforementioned wireless networks and radio technologies, as well as other wireless networks and radio technologies. For clarity, although aspects are described herein using terms commonly associated with 3G and / or 4G wireless technologies, aspects of this disclosure can be applied in other generation-based communication systems, including NR technology, such as 5G and its successors.

[0041] New radio (NR) access (e.g., 5G technology) can support a variety of wireless communication services, such as enhanced mobile broadband (eMBB) targeting wide bandwidth (e.g., 80 MHz or higher), millimeter wave (mmW) targeting high carrier frequencies (e.g., 25 GHz or higher), massive machine-type communication (mMTC) targeting non-backward-compatible MTC technologies, and / or mission-critical communication 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) to meet corresponding quality of service (QoS) requirements. Furthermore, these services can coexist in the same subframe.

[0042] Example wireless communication system

[0043] Figure 1 An example wireless communication network 100 in which various aspects of this disclosure can be performed is described. For example, a UE 120 in the wireless communication network 100 may include components configured to perform (or assist UE 120 in performing) the following references. Figure 16 The described operation 1600 is a UL subband precoding module. Similarly, base station 120 (e.g., gNB) may include modules configured to perform (or assist base station 120 in performing) the following references. Figure 17 The described operation is for the UL sub-band pre-encoding module of the 1700.

[0044] like Figure 1As explained, the wireless communication network 100 may include several base stations (BS) 110 and other network entities. A BS may be a station communicating with a user equipment (UE). Each BS 110 may provide communication coverage for a specific geographic area. In 3GPP, the term "cell" may refer to the coverage area of ​​a B-node (NB) and / or the NB subsystem serving that coverage area, depending on the context in which the term is used. In NR systems, the terms "cell" and next-generation B-node (gNB or gNodeB), NRBS, 5G NB, access point (AP), or transmit / receive point (TRP) may be interchangeable. In some examples, a cell may not be stationary, and the geographic area of ​​a cell may move depending on the location of a mobile BS. In some examples, base stations may interconnect with each other and / or interconnect to one or more other base stations or network nodes (not shown) in the wireless communication network 100 via various types of backhaul interfaces, such as direct physical connections, wireless connections, virtual networks, or the like using any suitable transport network.

[0045] Generally, any number of wireless networks can be deployed in a given geographical area. Each wireless network can support a specific Radio Access Technology (RAT) and can operate on one or more frequencies. A RAT may also be referred to as a radio technology, air interface, etc. A frequency may also be referred to as a carrier, subcarrier, frequency channel, frequency modulation, subband, etc. Each frequency can support a single RAT in a given geographical area to avoid interference between wireless networks using different RATs. In some cases, NR or 5G RAT networks can be deployed.

[0046] A BS can provide communication coverage for macrocells, picocells, femtocells, and / or other types of cells. Macrocells can cover a relatively large geographic area (e.g., a radius of several kilometers) and allow unrestricted access by UEs with a service subscription. Picocells can cover a relatively small geographic area and allow unrestricted access by UEs with a service subscription. Femtocells can cover a relatively small geographic area (e.g., a residential area) and allow restricted access by UEs associated with that femtocell (e.g., UEs in a Closed Subscriber Group (CSG), UEs of users in a residential building, etc.). A BS used for macrocells may be referred to as a macro BS. A BS used for picocells may be referred to as a pico BS. A BS used for femtocells may be referred to as a femto BS or a home BS. Figure 1In the example shown, BS 110a, 110b, and 110c can be macro BSs for macro cells 102a, 102b, and 102c, respectively. BS 110x can be a pico BS for pico cell 102x. BS 110y and 110z can be femto BSs for femto cells 102y and 102z, respectively. A BS can support one or more (e.g., three) cells.

[0047] The wireless communication network 100 may also include relay stations. A relay station is a station that receives transmissions of data and / or other information from an upstream station (e.g., a BS or a UE) and transmits such transmissions to a downstream station (e.g., a UE or a BS). A relay station may also be a UE relaying transmissions for other UEs. Figure 1 In the example shown, relay station 110r can communicate with BS 110a and UE 120r to facilitate communication between BS 110a and UE 120r. A relay station may also be referred to as a relay BS, relay, etc.

[0048] The wireless communication network 100 can be a heterogeneous network comprising different types of base stations (BSs) (e.g., macro BSs, pico BSs, femto BSs, relays, etc.). These different types of BSs may have different transmit power levels, different coverage areas, and different effects on interference in the wireless communication network 100. For example, a macro BS may have a high transmit power level (e.g., 20 watts), while a pico BS, femto BS, and relay may have a lower transmit power level (e.g., 1 watt).

[0049] The wireless communication network 100 can support synchronous or asynchronous operation. For synchronous operation, each BS can have similar frame timing, and transmissions from different BSs can be roughly aligned in time. For asynchronous operation, each BS can have different frame timing, and transmissions from different BSs may not be aligned in time. The techniques described herein can be used for both synchronous and asynchronous operations.

[0050] Network controller 130 can be coupled to a group of BSs and provide coordination and control over these BSs. Network controller 130 can communicate with BS 110 via backhaul. BS 110 can also communicate with each other via wireless or wired backhaul (e.g., directly or indirectly).

[0051] UE 120 (e.g., 120x, 120y, etc.) may be distributed throughout the wireless communication network 100, and each UE may be stationary or mobile. A UE may also be referred to as a mobile station, terminal, access terminal, subscriber unit, station, client equipment (CPE), cellular phone, smartphone, personal digital assistant (PDA), wireless modem, wireless communication device, handheld device, laptop computer, cordless phone, wireless local loop (WLL) station, tablet computer, camera, gaming device, netbook, smartbook, ultrabook, appliance, medical device or medical equipment, biometric sensor / device, wearable device (such as smartwatch, smart clothing, smart glasses, smart wristband, smart jewelry (e.g., smart ring, smart bracelet, etc.)), entertainment device (e.g., music device, video device, satellite radio, etc.), vehicle component or sensor, smart meter / sensor, industrial manufacturing equipment, GPS device, or any other suitable device configured to communicate via wireless or wired media. Some UEs may be considered machine-type communication (MTC) devices or evolved MTC (eMTC) devices. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, location tags, etc., which can communicate with a BS, another device (e.g., a remote device), or another entity. Wireless nodes can provide connectivity to or to a network (e.g., a wide area network such as the Internet) or a cellular network, for example, via wired or wireless communication links. Some UEs can be considered Internet of Things (IoT) devices, which can be narrowband IoT (NB-IoT) devices.

[0052] 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, often referred to as frequency modulation, frequency slots, etc. Each subcarrier can be modulated with data. Generally, modulation symbols are transmitted 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 could be 15 kHz, and the minimum resource allocation (called a "resource block" (RB)) could be 12 subcarriers (or 180 kHz). Therefore, for system bandwidths of 1.25, 2.5, 5, 10, or 20 MHz, the nominal Fast Fourier Transform (FFT) size could be 128, 256, 512, 1024, or 2048, respectively. The system bandwidth can also be divided into subbands. For example, a subband can cover 1.08MHz (i.e., 6 resource blocks), and for system bandwidths of 1.25, 2.5, 5, 10, or 20MHz, there can be 1, 2, 4, 8, or 16 subbands, respectively.

[0053] Communication systems (such as NR) can utilize OFDM with a cyclic prefix (CP) on both the uplink and downlink, and include support for half-duplex operation using Time Division Duplex (TDD). Beamforming is supported, and beam direction can be dynamically configured. MIMO transmission with precoding is also supported. MIMO configuration in DL can support up to 8 transmit antennas (with up to 8 streams in multilayer DL transmission) and up to 4 streams per UE. Multilayer transmission with up to 4 streams per UE is supported. Up to 8 serving cells can be used to support aggregation of multiple cells.

[0054] In some examples, access to the air interface can be scheduled. A scheduling entity (e.g., a BS) allocates resources for communication among some or all devices and equipment within its service area or cell. The scheduling entity may be responsible for scheduling, assigning, reconfiguring, and releasing resources for one or more subordinate entities. That is, for scheduled communication, the subordinate entity utilizes the resources allocated by the scheduling entity. A base station is not the only entity that can be used as a scheduling entity. In some examples, a UE may act as a scheduling entity and can schedule resources for one or more subordinate entities (e.g., one or more other UEs), and other UEs may utilize the resources scheduled by that UE for wireless communication. In some examples, a UE may act as a scheduling entity in a peer-to-peer (P2P) network and / or in a mesh network. In the mesh network example, UEs may communicate directly with each other in addition to communicating with a scheduling entity.

[0055] exist Figure 1In the diagram, a solid line with a double arrow indicates the desired transmission between the UE and the serving BS, which is the BS designated to serve the UE on the downlink and / or uplink. A thin dashed line with a double arrow indicates interference transmission between the UE and the BS.

[0056] Figure 2 The illustration shows examples of communication protocol stacks for implementing a RAN (e.g., such as RAN 100) according to various aspects of this disclosure. The illustrated communication protocol stack 200 can be implemented by devices operating in a wireless communication system (such as a 5G NR system) (e.g., wireless communication network 100). In various examples, these layers of the protocol stack 200 can be implemented as separate software modules, portions of a processor or ASIC, portions of non-co-located devices connected by communication links, or various combinations thereof. Co-located and non-co-located implementations can, for example, be used in the protocol stack for a network access device or a UE. Figure 2 As shown, the system can support various services on one or more protocols. One or more protocol layers of protocol stack 200 can be implemented by AN and / or UE.

[0057] like Figure 2 As shown, protocol stack 200 in AN( Figure 1 The layers 205, 210, 215, 220, 225, and 230 can be implemented by AN. For example, CU-CP can implement RRC layer 205 and PDCP layer 210. DU can implement RLC layer 215 and MAC layer 220. AU / RRU can implement (various) PHY layers 225 and (various) RF layers 230. PHY layer 225 may include high PHY layer and low PHY layer.

[0058] The UE can implement the entire protocol stack 200 (e.g., RRC layer 205, PDCP layer 210, RLC layer 215, MAC layer 220, (various) PHY layers 225 and (various) RF layers 230).

[0059] Figure 3 The explanation (e.g.) Figure 1 The example components of BS 110 and UE 120 depicted herein can be used to implement various aspects of this disclosure. For example, antenna 352, processors 366, 358, 364 and / or controller / processor 380 of UE 120 can be configured (or used to) perform Figure 16 Operation 1600, and / or the antenna 334, processors 320, 330, 338, and / or controller / processor 340 of BS 110 may be configured (or used to) perform the following (see reference below). Figure 17 The described operation is 1700.

[0060] At BS 110, the transmit processor 320 can receive data from data source 312 and control information from controller / processor 340. This control information can be used for the Physical Broadcast Channel (PBCH), Physical Control Format Indicator Channel (PCFICH), Physical Hybrid ARQ Indicator Channel (PHICH), Physical Downlink Control Channel (PDCCH), Group Shared PDCCH (GC PDCCH), etc. This data can be used for the Physical Downlink Shared Channel (PDSCH), etc. The processor 320 can process (e.g., encoding and symbol mapping) the data and control information to obtain data symbols and control symbols respectively. The processor 320 can also generate reference symbols (e.g., primary synchronization signal (PSS), secondary synchronization signal (SSS), and cell-specific reference signal (CRS). The transmit (TX) multiple-input multiple-output (MIMO) processor 330 can perform spatial processing (e.g., precoding) on ​​data symbols, control symbols, and / or reference symbols where applicable, and can provide the output symbol stream to modulators (MODs) 332a to 332t. Each modulator 332 can process its respective output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator can further process (e.g., convert to analog, amplify, filter, and up-convert) the output sample stream to obtain a downlink signal. The downlink signal from modulators 332a to 332t can be transmitted via antennas 334a to 334t, respectively.

[0061] At UE 120, antennas 352a to 352r can receive downlink signals from base station 110 and provide the received signals to demodulators (DEMODs) 354a to 354r in the transceiver, respectively. Each demodulator 354 can condition (e.g., filter, amplify, down-convert, and digitize) the corresponding received signal to obtain an input sample. Each demodulator can further process the input sample (e.g., for OFDM, etc.) to obtain received symbols. MIMO detector 356 can obtain the received symbols from all demodulators 354a to 354r, perform MIMO detection on these received symbols where applicable, and provide detected symbols. Receiver processor 358 can process (e.g., demodulate, deinterleave, and decode) these detected symbols, provide the decoded data to UE 120 to data sink 360, and provide the decoded control information to controller / processor 380.

[0062] In a MIMO system, the transmitter (e.g., BS 110) includes multiple transmit antennas 354a to 354t, and the receiver (e.g., UE 120) includes multiple receive antennas 352a to 352r. Therefore, multiple signal paths 394 exist from the transmit antennas 354a to 354t to the receive antennas 352a to 352r. Each of the transmitter and receiver can be implemented, for example, in UE 120, BS 110, or any other suitable wireless communication device.

[0063] The use of such multi-antenna techniques enables wireless communication systems to utilize the spatial domain to support spatial multiplexing, beamforming, and transmit diversity. Spatial multiplexing can be used to simultaneously transmit different data streams (also known as layers) on the same time-frequency resources. These data streams can be transmitted to a single UE to increase the data rate or to multiple UEs to increase the overall system capacity, the latter being known as multi-user MIMO (MU-MIMO). This is achieved by spatially precoding each data stream (i.e., multiplying these data streams by different weights and phase shifts) and then transmitting each spatially precoded stream over multiple transmit antennas on the downlink. The spatially precoded data streams arrive at the UE(s) with different spatial signatures, which allow each UE to recover one or more data streams intended for that UE. On the uplink, each UE transmits spatially precoded data streams, which allows the base station to identify the source of each spatially precoded data stream.

[0064] The number of data streams or layers corresponds to the transmission rank. Generally, the rank of a MIMO system is limited by the lower of the number of transmit or receive antennas. Additionally, channel conditions at the UE and other considerations (such as available resources at the base station) can also affect the transmission rank. For example, the rank assigned to a particular UE on the downlink (and therefore the number of transmission layers) can be determined based on a rank indicator (RI) transmitted from that UE to the base station. The RI can be determined based on the antenna configuration (e.g., the number of transmit and receive antennas) and the measured signal-to-interference-plus-noise ratio (SINR) on each receive antenna. The RI can indicate, for example, the number of layers that can be supported under the current channel conditions. The base station can use the RI along with resource information (e.g., available resources and the amount of data to be scheduled for the UE) to assign a transmission rank to the UE.

[0065] On the uplink, at UE 120, transmit processor 364 can receive and process data from data source 362 (e.g., data for the Physical Uplink Shared Channel (PUSCH)) and control information from controller / processor 380 (e.g., control information for the Physical Uplink Control Channel (PUCCH)). Transmit processor 364 can also generate reference symbols for reference signals (e.g., probe reference signals (SRS)). Symbols from transmit processor 364 can be pre-encoded by TX MIMO processor 366 where applicable, further processed by demodulators 354a to 354r in the transceiver (e.g., for SC-FDM, etc.), and transmitted to base station 110. At BS 110, uplink signals from UE 120 can be received by antenna 334, processed by modulator 332, detected by MIMO detector 336 where applicable, and further processed by receive processor 338 to obtain decoded data and control information transmitted by UE 120. The receiver processor 338 can provide decoded data to the data trap 339 and decoded control information to the controller / processor 340.

[0066] Controllers / processors 340 and 380 can direct operations at BS 110 and UE 120, respectively. Processor 340 and / or other processors and modules at BS 110 can execute or direct the execution of processes of the techniques described herein. Memory 342 and 382 can store data and program code for use by BS 110 and UE 120, respectively. Scheduler 344 can schedule the UE for downlink and / or uplink data transmission.

[0067] Figure 4 This is a diagram illustrating an example of frame format 400 for NR. The transmission timeline for each of the downlink and uplink can be divided into radio frames. Each radio frame may have a predetermined duration (e.g., 10 ms) and may be divided into 10 subframes with indices 0 to 9, each subframe being 1 ms long. Each subframe may include a variable number of time slots, depending on the subcarrier spacing. Each time slot may include a variable number of symbol periods (e.g., 7 or 14 symbols), depending on the subcarrier spacing. An index may be assigned to the symbol periods in each time slot. A mini-time slot (which may be referred to as a sub-time slot structure) refers to a transmission time interval with a duration less than a time slot (e.g., 2, 3, or 4 symbols). Each symbol in a time slot may indicate the link direction for data transmission (e.g., DL, UL, or flexible), and the link direction for each subframe can be dynamically switched. The link direction may be based on the time slot format. Each time slot may include DL / UL data and DL / UL control information.

[0068] In NR, a synchronization signal (SS) block is transmitted. The SS block consists of the PSS, SSS, and two symbols, PBCH. The SS block can be transmitted at fixed time slot positions (such as...). Figure 4 The PSS and SSS are transmitted in symbols 0-3 shown in the diagram. The PSS and SSS can be used by the UE for cell search and acquisition. The PSS provides half-frame timing, and the SS provides CP length and frame timing. The PSS and SSS provide cell identity. The PBCH carries basic system information such as downlink system bandwidth, timing information within the radio frame, SS burst set periodicity, and system frame number. SS blocks can be organized into SS bursts to support beam sweeping. Further system information (such as Residual Minimum System Information (RMSI), System Information Block (SIB), and Other System Information (OSI)) can be transmitted in certain subframes on the Physical Downlink Shared Channel (PDSCH). SS blocks can be transmitted up to 64 times, for example, up to 64 different beam directions for mmW. Up to 64 transmissions of an SS block are called an SS burst set. SS blocks in an SS burst set are transmitted in the same frequency region, while SS blocks in different SS burst sets can be transmitted at different frequency locations.

[0069] The UE can operate in various radio resource configurations, including configurations associated with transmitting pilot signals using a dedicated resource set (e.g., Radio Resource Control (RRC) dedicated state) or configurations associated with transmitting pilot signals using a shared resource set (e.g., RRC shared state). When operating in RRC dedicated state, the UE can select a dedicated resource set for transmitting pilot signals to the network. When operating in RRC shared state, the UE can select a shared resource set for transmitting pilot signals to the network. In either case, the pilot signals transmitted by the UE can be received by one or more network access devices (such as AN, or DU, or portions thereof). Each receiving network access device can be configured to receive and measure pilot signals transmitted on the shared resource set, and also to receive and measure pilot signals transmitted on the dedicated resource set allocated to the UE, wherein the network access device is a member of a set of monitoring network access devices for that UE. One or more receiving network access devices, or a CU to which the receiving network access device transmits pilot signal measurements, can use these measurements to identify the UE's serving cell or initiate changes to the serving cell for one or more UEs.

[0070] Example CSI report configuration

[0071] Channel State Information (CSI) refers to the channel properties of a communication link. CSI can represent, for example, the combined effects of scattering, fading, and power attenuation with distance between the transmitter and receiver. Channel estimation using pilots (such as a CSI reference signal (CSI-RS)) can be performed to determine these effects on the channel. CSI can be used to adapt transmissions based on current channel conditions, which is useful for achieving reliable communication, especially in high data rate communication in multi-antenna systems. CSI is typically estimated, quantized, and fed back to the transmitter at the receiver.

[0072] The time and frequency resources that the UE can use to report CSI are controlled by the base station (e.g., gNB). CSI may include Channel Quality Indicator (CQI), Precoding Matrix Indicator (PMI), CSI-RS Resource Indicator (CRI), SS / PBCH Block Resource Indicator (SSBRI), Layer Indicator (LI), Rank Indicator (RI), and / or L1-RSRP. However, as described below, additional or other information may be included in the report.

[0073] The base station can configure the UE for CSI reporting. For example, the BS configures one or more CSI reporting configurations for the UE. The CSI reporting configuration can be provided to the UE via higher-layer signaling, such as Radio Resource Control (RRC) signaling (e.g., CSI-ReportConfig). The CSI reporting configuration can be associated with CSI-RS resources used for channel measurement (CM), interference measurement (IM), or both. The CSI reporting configuration configures the CSI-RS resources used for measurement (e.g., CSI-ResourceConfig). The CSI-RS resources provide the UE with a configuration of CSI-RS ports or groups of CSI-RS ports mapped to time and frequency resources (e.g., resource elements (REs)). The CSI-RS resources can be zero-power (ZP) or non-zero-power (NZP) resources. At least one NZP CSI-RS resource can be configured for CM.

[0074] For a Type II single-panel codebook, the PMI is a linear combination of beams; it has a subset of orthogonal beams to be used for linear combination, and for each beam has amplitude and phase according to layer, according to polarization. For any type of PMI, broadband (WB) PMIs and / or subband (SB) PMIs can exist as configured.

[0075] CSI reporting configuration can be configured for UEs using aperiodic, periodic, or semi-persistent CSI reporting. For periodic CSI, the UE can be configured with periodic CSI-RS resources. Periodic and semi-persistent CSI reporting on the Physical Uplink Control Channel (PUCCH) can be triggered via RRC or Media Access Control (MAC) control elements (CE). For aperiodic and semi-persistent CSI on the Physical Uplink Shared Channel (PUSCH), the BS can signal a CSI report trigger to the UE, instructing the UE to send a CSI report for one or more CSI-RS resources, or configure a CSI-RS report trigger state (e.g., CSI-AperiodicTriggerStateList and CSI-SemiPersistentOnPUSCH-TriggerStateList). CSI report triggering for aperiodic and semi-persistent CSI on the PUSCH can be provided via Downlink Control Information (DCI). CSI-RS triggering can be signaling to the UE to transmit CSI-RS for CSI-RS resources.

[0076] The UE can report CSI feedback based on CSI reporting configuration and CSI reporting triggering. For example, the UE can measure the channel associated with the CSI of the CSI used for triggering the CSI-RS resource. Based on this measurement, the UE can select a preferred CSI-RS resource. The UE reports the CSI feedback of the selected CSI-RS resource. LI can be calculated based on the reported CQI, PMI, RI, and CRI; CQI can be calculated based on the reported PMI, RI, and CRI; PMI can be calculated based on the reported RI and CRI; and RI can be calculated based on the reported CRI.

[0077] Each CSI reporting configuration can be associated with a single downlink bandwidth portion (BWP). The CSI reporting setting configuration can define the CSI reporting band as a subset of the subbands of the BWP. The associated DL BWP can be indicated by higher-level parameters (e.g., bwp-Id) in the CSI reporting configuration used for channel measurements and contains parameters(s) for a CSI reporting band, such as codebook configuration, time-domain behavior, frequency granularity of the CSI, measurement constraint configuration, and the number of CSI-related parameters the UE needs to report. Each CSI resource setting can reside within a DL BWP identified by higher-level parameters, and all CSI resource settings can be linked to CSI reporting settings with the same DL BWP.

[0078] In some systems, the UE can be configured via higher-layer signaling (e.g., in the CSI report configuration) to have one of two possible subband sizes (e.g., the reportFreqConfiguration included in CSI-ReportConfig), indicating the frequency granularity of the CSI report, where the subband can be defined as... Each contiguous Physical Resource Block (PRB) depends on the total number of PRBs in that bandwidth segment. The UE may further receive indications of subbands for which it requests CSI feedback. In some examples, a subband mask is configured for the requested subband for CSI reporting. The UE calculates a precoder for each requested subband and finds a PMI that matches the calculated precoder on each subband.

[0079] Compressed CSI Feedback Coefficient Report

[0080] As discussed above, a User Equipment (UE) can be configured for Channel State Information (CSI) reporting, for example, by receiving CSI configuration messages from a base station. In some systems (e.g., Release 15 5G NR), the UE can be configured to report at least Type II precoders across configured frequency domain (FD) cells. For example, for the precoder matrix W of layer r. r Including the W1 matrix and W 2，r The matrix, W1 matrix, uses spatial compression to select a subset of the beam, while W... 2，r Matrix report (for cross-polarization) of the linear combination coefficients for the selected beam (2L) of the transverse FD cell:

[0081] in

[0082] Where b i It is the selected beam, c i It is the set of linear combination coefficients (i.e., W) 2，r The matrix entries), L is the number of selected spatial beams, and N3 corresponds to the number of frequency units (e.g., sub-bands, resource blocks (RBs), etc.). In some configurations, L is configured via RRC. The precoder is based on a linear combination of DFT beams. Type II codebooks can improve MU-MIMO performance. In some configurations that take into account the presence of two polarizations, W 2，r The matrix has a size of 2L×N3.

[0083] In some systems (e.g., version 165GNR), the UE can be configured to report FD compression precoder feedback to reduce CSI reporting overhead. For example... Figure 5 As shown, the precoder matrix (W) of layer i (where i = 0, 1) 2，i FD compression can be used. The matrix is ​​used to compress the precoder matrix to a size of 2L x M (where M is the network configured and communicated via RRC or DCI in the CSI configuration message, and M < N^3). The matrix is ​​given as follows:

[0084]

[0085] Where the precoder matrix W i (Not shown) has P = 2N1N2 rows (spatial domain, number of ports) and N3 columns (frequency domain compression units containing RBs or report subbands), wherein M bases are independently selected for each layer in layer 0 and layer 1. Matrix 520 includes linear combination coefficients (amplitude and common phase), where each element represents a tap coefficient of the beam. As shown... Matrix 520 is defined by a size of 2L x M, where one row corresponds to a spatial beam (not shown) of size P x ​​2L W1 (where L is the network configured via RRC), and one entry represents a tap coefficient of that spatial beam. The UE can be configured to report (e.g., CSI reporting). The linear combination coefficient subset K0 of matrix 520 is less than 2LM. For example, the UE can report K as interpreted by the shaded square. NZ，i <K0 coefficient (where K NZ，i The maximum number of non-zero coefficients corresponding to layer i = 0 or 1, and K0 is the network configured via RRC (unreported coefficients are set to zero). In some configurations, The entries in matrix 520 correspond to One row of matrix 530. In the example shown, at layer 0. Matrix 520 and layer 1 Both matrices are 2L x M.

[0086] Matrix 530 includes basis vectors (each row is a basis vector) used to perform compression in the frequency domain. In the example shown, at layer 0... Matrix 530 and layer 1 Matrix 560 includes both the M=4FD basis from the N3 candidate DFT basis (explained as shaded rows). In some configurations, the UE can report via CSI reporting. A subset of the selected basis of the matrix. Specifically, M basis points are selected at layer 0 and layer 1. That is, the M basis points selected at layer 0 can be the same as, partially overlap with, or not overlap with the M basis points selected at layer 1.

[0087] Frequency domain compression for high-rank indicators

[0088] Figure 6 Three alternative examples of the FD base used to determine a specific RI are explained. Each example is explained as a table, where the left column indicates the RI (e.g., RI = {1, 2, 3, 4}) and the bottom row indicates the transport layer (e.g., layer 0, layer 1, layer 2, layer 3). That is, the layer number indicates the transport rank, where RI = 1 is restricted to a single spatial layer, RI = 2 corresponds to two spatial layers, RI = 3 corresponds to three spatial layers, and RI = 4 corresponds to four spatial layers. Accordingly, Type II CSI can be associated with a UE having up to four spatial layers.

[0089] In some configurations using FD compression, regardless of rank, each layer reports up to K0 non-zero coefficients (NZCs), and the total number of NZCs across all layers is constrained to 2K0. That is, for rank 1 and rank 2, only the per-layer constraint needs to be considered, because the total NZC constraint across layers becomes redundant (since the total NZC for these two layers (with a constraint of K0 per layer) will not exceed 2K0). On the other hand, for rank 3 and rank 4, both the per-layer constraint and the total constraint will be considered.

[0090] Similarly, the FD basis (M) of RI = {3, 4} i This is equivalent to RI=2. In one example, each layer (layer 0 and layer 1) of RI=2 uses M number of FD bases, thus making the FD bases across all four layers of RI=4 equivalent to 2M. That is, for a given RI, M i It can be described as:

[0091]

[0092] exist Figure 5 In the example shown, Matrix 530 includes the FD basis M = 4 (M0 = 4), and Matrix 560 includes FD basis M = 4 (M1 = 4), thus for RI = 2, there are a total of 8 FD basis. Therefore, for RI = {3, 4}, the total number of FD basis across all four layers should be equivalent to M0 + M1 or 2M (e.g., for RI = {3, 4}, between 6 and 10 FD basis).

[0093] like Figure 6 As shown in Table 610, an example is provided to make the total number of FD bases for RI = {3, 4} equivalent to RI = 2. In this example, for RI = {3, 4}, the FD base for each layer in layers 0-3 is M2. In some cases, in standard specifications, M2 can be set to be equal to M / 2 or 2 / 3*M. The value of M can be determined, for example, by the following equation:

[0094] M = ceil(p*N3), and M2 can be determined by the following equation:

[0095] M2 = ceil(v0 * N3),

[0096] Where p and v0 are jointly configured, for example, according to:

[0097] (p, v0) = (1 / 2, 1 / 4), (1 / 4, 1 / 4) and (1 / 4, 1 / 8).

[0098] In various aspects of the techniques described herein, for example, by receiving CSI configuration messages from a base station, the UE can be configured for CSI reporting. In some systems, the UE can be configured to report at least a Type II precoder across configured frequency domain (FD) cells. For example, a precoder for a certain layer l over N3 subbands can be expressed as a matrix W of size P×N3. l :

[0099]

[0100] In this equation, L is the number of one (or more) spatial domain (SD) bases (e.g., spatial beams) configured by the RRC signaling configured in the CSI report, having i = 0, 1, ..., L-1. yes There are SD bases and they are applied to two polarizations. The SD bases are based on DFT and have indexes. and The SD base can be written as:

[0101]

[0102]

[0103] In this equation, N1 and N2 represent the first and second dimensions of the configured codebook, respectively. In some cases, these parameters may refer to the number of antenna elements in the vertical and horizontal dimensions at the base station, respectively. The oversampling factor is indicated by 01 and 02.

[0104] Furthermore, having m = 0, 1, ..., M l f m (m) is N3×1 FD bases (i.e., M is a 1×N3 row vector, which can also be called a transitive basis. l This refers to the number of FD bases selected for layer l, and it is derived based on the RRC configuration. In some cases, for each layer of rank 1 and rank 2, there are M bases, and The value is determined by the ratio ρ configured by RRC, and R is the number of precoding matrix indicator (PMI) subbands within a CQI subband. The FD basis can be a DFT basis and has an index. The FD base is expressed as:

[0105]

[0106] As mentioned above, the coefficients of a linear combination can include three parts: parameter This represents the amplitude reference used for the first polarization, while This represents the amplitude reference used for the second polarization. These values ​​are universal for all coefficients associated with the corresponding polarization (e.g., and ).parameter This represents the (difference) magnitude of the coefficients in the first polarization, which is related to the indexed coefficients. and The SD base is associated with, and with, an index The FD base is associated with, and This represents the (difference) magnitude of the coefficients in the second polarization, which are related to the indexed coefficients. and The SD base is associated with, and with, an index The FD basis is associated. Similarly, the parameters This represents the (difference) magnitude of the coefficients in the first polarization, which is related to the indexed coefficients. and The SD base is associated with, and with, an index The FD base is associated with, and This represents the (difference) magnitude of the coefficients in the second polarization, which are related to the indexed coefficients. and The SD base is associated with, and with, an index The FD base is associated with it.

[0107] For RI = {1, 2}, for each layer, the number of FD bases is M = M 1，2 ,in The value is determined by the ratio ρ configured by RRC, and R is the number of precoding matrix indicator (PMI) subbands within a CQI subband. For RI = {3, 4}, the number of FD bases M = M 3，4 ,in The value of is determined by the ratio v0 configured by RRC. Possible combinations of ρ and v0 include Furthermore, for each layer with RI = {1, 2, 3, 4}, the UE is configured to report all 2LMs. 1，2 Or all 2LM 3，4 A subset of coefficients, with unreported coefficients set to zero. The maximum number of coefficients to be reported per layer is K0, and the maximum total number of coefficients to be reported across all layers is 2K0, where... and It is configured via RRC. Note that, regardless of the rank, K0 uses M. 1，2 To calculate.

[0108] In the case of codebook operation with FD compression, for layer l, its precoder spanning N3 FD units (also known as PMI subbands) is composed of a size N t A matrix W of size N3 l The following is given:

[0109]

[0110] Among them W1, and W f as follows:

[0111]

[0112] like Figure 7 The three matrices are explained graphically in the text (note that, although...) Figure 7 Only two layers are shown, but in reality, there can be three or four layers with the same structure. The only difference is the number of FD bases and non-zero coefficients or the number of NZCs. It can be written as:

[0113]

[0114]

[0115]

[0116] The SD base is based on DFT and has an index. and The SD base is written as:

[0117]

[0118]

[0119] An FD basis can be a DFT basis and has an index. The FD base is expressed as:

[0120]

[0121] coefficient and It can be described as follows:

[0122]

[0123] Given these definitions, more precisely, the linear combination representation can be expressed as:

[0124]

[0125] Example UL subband precoding via linear combination of FD bases

[0126] Some deployments (e.g., NR versions 15 and 16 systems) support both codebook-based and non-codebook-based transport schemes for uplink transport with wideband precoders. Codebook-based UL transport is based on BS feedback and can be used in situations where reciprocity may not be valid.

[0127] Figure 8 This is a call flowchart illustrating an example of a conventional codebook-based UL transmission using a wideband precoder. As explained, the UE transmits an (uncoded) SRS with up to two SRS resources (each resource having 1, 2, or 4 ports). The gNB measures the SRS and, based on that measurement, selects an SRS resource and the wideband precoder to be applied to those SRS ports within the selected resource.

[0128] As explained, the gNB configures the selected SRS resources for the UE via the SRS Resource Indicator (SRI) and the wideband precoder for the UE via the Transmit Precoder Matrix Indicator (TPMI). For dynamic granting, the SRI and TPMI can be configured via DCI format 0_1. For configured granting (e.g., for semi-persistent uplink), the SRI and TPMI can be configured via RRC or DCI.

[0129] The UE determines the selected SRS resource based on the SRI and the precoding based on the TPMI, and transmits the PUSCH accordingly. Figure 9 Explain how a wideband precoder (as indicated by TPMI) can map the transport layer to the PUSCH port. Figure 12A-12F The explanation describes a set of example precoder matrices for various layer and antenna port combinations that can be selected via the TPMI index.

[0130] Figure 10 This is a call flow diagram illustrating an example of non-codebook-based UL transmission. As explained, the UE transmits (precoded) SRS. Although this example shows 2 SRS resources, the UE can use up to 4 SRS resources (each with 1 port) for transmission. The gNB measures the SRS and selects one or more SRS resources based on that measurement. In this case, since the UE transmits precoded SRS by selecting SRS resources, the gNB also efficiently selects the precoder. For non-codebook-based UL transmission, each SRS resource corresponds to a layer. The precoder for this layer is actually the precoder for the SRS simulated by the UE. Selecting N SRS resources means rank N. The UE uses the same precoder as the SRS to transmit the PUSCH.

[0131] As explained, the gNB configures the selected SRS resources for the UE via the SRS Resource Indicator (SRI). For dynamic granting, the SRI can be configured via DCI format 0_1. For configured granting, the SRI can be configured via RRC or DCI.

[0132] In this scenario, the UE determines the selected SRS resource based on the SRI, selects the same precoder used when transmitting the selected SRS resource, and transmits the PUSCH accordingly. Figure 11 It explains how to efficiently select the PUSCH port via the SRS ports across the selected SRS resources (or resources).

[0133] As mentioned above, wideband precoding is typically used in conventional (e.g., versions 15 and 16) systems. However, in some cases, subband precoding may provide gain, especially when the number of Tx layers is greater than or equal to 4. One challenge for subband precoding of UL transmissions is how to define the transmission scheme for subband precoding and (e.g., TPMI from gNB to UE) related signaling.

[0134] This disclosure proposes a UL transmission scheme for subband precoding via a linear combination of frequency domain (FD) bases. As will be described in more detail below, for each antenna port, one or more FD bases can be applied across all subbands, and specific coefficients can be associated with each base. The gNB (e.g., based on SRS transmission) measures the UL channel and determines an optimal set containing one or more FD bases and associated coefficients, then configures these FD bases and coefficients to the UE. The resulting subband-based precoding can lead to significant performance gains without imposing an excessive burden on UE implementation.

[0135] Figure 13 This is a call flow diagram illustrating an example UL transmission with subband precoding. As explained, the UE can transmit (uncoded) SRS. Based on measurements of the SRS, the base station (gNB) selects a set of FD bases and linear combination coefficients associated with each FD base (collectively included as TPMI).

[0136] The gNB then signals the TPMI to the UE. The gNB can transmit the determined FD basis and linear combination coefficients to the UE via DCI, RRC, or MAC CE. The UE then transmits a PUSCH with subband precoding based on the TPMI (e.g., using a linear combination of the FD basis based on the signaled coefficients).

[0137] The UL preencoder spanning N3 FD units, layer l∈{0,…,v-1}, can be expressed as:

[0138]

[0139] Among them, the size is 1×N3 It is the m-th FD base applied to SRS port i in layer 1, and c 0，m，l It is with the base The associated linear combination coefficients. Figure 14 The diagram illustrates how linear combinations of FD bases can be applied to four SRS ports (ports 0-3) across N3 FD cells. FD cells can be UL subbands, UL physical resource groups (PRGs), RBs, or subcarriers.

[0140] like Figures 15A-15D As explained, there are various options for configuring FD bases used for UL subband precoding. Each FD base can be of any suitable type, such as a DFT base, DCT base, Slepian-wolf base, or fractional DFT base. FD base sets can be applied in a layer-shared or layer-dedicated manner, and in an antenna port-shared or antenna port-dedicated manner.

[0141] For example, such as Figure 15A As explained in the paper, in the “layer sharing / port sharing” approach, the FD base can include different sets of FD bases, where each set of FD bases is applied to each of the multiple antenna ports for a given transmission layer.

[0142] like Figure 15B As explained in the article, in the “layer-specific / port-shared” approach, the same FD base set can be applied to each of multiple antenna ports and each of multiple space layers.

[0143] like Figure 15C As explained, in the "layer-shared / port-dedicated" approach, the FD base can include different sets of FD bases for different antenna ports. For a given antenna port, the same set of FD bases is applied across multiple spatial layers.

[0144] like Figure 15D As explained in the text, in the “layer-specific / port-specific” approach, the FD base can include different sets of FD bases for different antenna ports, and different sets of FD bases can be applied to different layers.

[0145] There are various methods for configuring linear coefficients. In some cases, from the total ∑ i，l M i，l In each FD base, gNB can further indicate K NZ ≤∑ i，l M i，l M are non-zero coefficients (assuming coefficients for unindicated ports are set to zero), where M i，l Indicates the number of FD bases on antenna port i and layer l.

[0146] In some cases, the configuration of the coefficients may depend on which of the FD basis methods is used (as described above). For example, for the selection of a layer-shared FD basis, K can be indicated. NZ ≤v×∑ i M i There are non-zero coefficients, where M i This indicates the number of FD bases on each antenna port i. For the selection of shared FD bases for ports, K can be indicated. NZ ≤p×∑ l M l There are non-zero coefficients, where M i This indicates the number of FD bases for each line port on layer l. For layer-shared and port-shared FD base selection, K can be indicated. NZ ≤p×v×M non-zero coefficients, where M indicates the number of FD bases for each daily line port in each layer.

[0147] The format and content of the coefficients can also vary depending on the options. For example, according to the first option, per-coefficient quantization can be used. In this case, amplitude quantization of A bits is used (e.g., |c...). i，m，l |). Alternatively, differential quantization can be indicated for coefficients at a specific port and at a specific layer (e.g., |c). i，m，l |=p ref，i，l ·p i，m，l In this case, the shared part (p) ref，i，l The ) can be A1 bits, while the differential part (p) i，m，l () can be A2 bits. It can indicate B-bit phase quantization (e.g., angle(c)). i，m，l )).

[0148] According to the second option, these coefficients can be indicated via joint coefficient quantization. In this case, non-zero coefficients... We can make joint selections from the candidate set, such as:

[0149]

[0150] Examples of these sets are in Figures 12A-12F The explanation comes from the Chinese.

[0151] In some scenarios, the gNB can configure the FD base and coefficients for the UE via two-stage DCI signaling (involving first and second DCI transmissions). In this scenario, the first DCI can provide sufficient information for the complete precoder. For example, the first DCI can indicate at least one (possibly more or all) FD base and corresponding coefficients. According to one option, per layer per FD base per port can indicate one coefficient (e.g., via per-coefficient quantization or joint quantization of individual coefficients across these ports, FD bases, and layers). According to another option, a reference amplitude for each layer can be indicated.

[0152] The second DCI can provide residual information for subband precoding. For example, the second DCI can indicate the remaining FD basis (if all basis bases are not included in the first DCI). The second DCI can also indicate the corresponding coefficients (e.g., the remaining coefficients or the differential power and phase of each of the coefficients).

[0153] Example UL subband precoding via linear combination of FD bases

[0154] The aspects of this disclosure provide mechanisms that can help provide some robustness for the two-stage DCI approach used for the aforementioned subband-based UL precoding, as will be described in more detail below, by providing sufficient information in each DCI for at least basic precoding. As a result, if only one of the DCIs can be successfully decoded, the UE can continue its PUSCH transmission, although the performance using basic precoding may be affected relative to the performance achievable using precoding provided by the two-stage DCI.

[0155] As referenced above Figure 8 As mentioned, for codebook-based UL precoding, the UE transmits (unprecoded) SRS (with up to two SRS resources, each with 1, 2, or 4 ports). The gNB measures the SRS and, based on the measurement, selects an SRS resource and a wideband precoder to apply to the SRS ports within the selected resource. The gNB configures the selected SRS resource for the UE via the SRI and the wideband precoder for the UE via the TPMI. The UE then uses the information provided via the TPMI for transmission.

[0156] As mentioned above, one way to enhance UL precoding performance is by introducing a SB-specific precoder. However, in some cases, such as at least for 4-Rx, simply using a SB-specific TPMI may not result in a significant performance gain. On the other hand, indicative SB-specific quantized singular value decomposition (SVD) precoders may be overly resource-intensive (due to the amount of information). Therefore, a resource-friendly approach with good performance gains is generally preferred.

[0157] As mentioned above, a resource-efficient approach is to use a linear combination of FD bases to estimate the SB-specific SVD precoder, where the FD bases and linear combination coefficients can be selectively reported to provide payload compression (this is generally referred to herein as FD-compressed UL SB precoding). Furthermore, due to the relatively limited DCI payloads supported by current standards, the two-stage DCI approach described above for providing compressed SVD precoder indication may be necessary in some situations.

[0158] The aspects of this disclosure provide mechanisms that can help provide some robustness or can be considered a fallback to the two-stage DCI approach if the UE can only decode one of the two DCIs. In other words, by providing information to at least one basic precoder, the UE can perform UL precoding even if it misses one of these DCIs.

[0159] Figure 15 illustrates an example operation 1500 for wireless communication by a UE for UL subband precoding, according to certain aspects of this disclosure. Operation 1500 can be performed, for example, by... Figure 1 or Figure 3 UE 120 is used to execute.

[0160] Operation 1500 begins at 1502, whereby the UE receives at least one of a first downlink control information (DCI) or a second DCI from a network entity, each DCI indicating at least one set of one or more sets containing one or more frequency domain (FD) bases and linear combination coefficients. At 1504, depending on whether the first DCI, the second DCI, or both are received, the UE determines subband precoding based on the first DCI, the second DCI, or a combination of the first and second DCIs. At 1506, the UE transmits the Physical Uplink Shared Channel (PUSCH) using this subband precoding.

[0161] Figure 16 This is a flowchart illustrating example operation 1600 for wireless communication by a network entity (e.g., a base station, such as an eNB or gNB) according to certain aspects of this disclosure. Operation 1600 can be performed, for example, by... Figure 1 Alternatively, BS 110 of 3 can be used to configure UE 120 for (operation 1500 according to Figure 15) UL subband precoding.

[0162] Operation 1600 begins at 1602 by sending at least a first downlink control information (DCI) and a second DCI to the user equipment (UE), each DCI indicating at least one set of one or more sets containing one or more frequency domain (FD) bases and linear combination coefficients. At 1604, the network entity processes the Physical Uplink Shared Channel (PUSCH) transmitted from the UE via subband precoding based on the first DCI, the second DCI, or a combination of the first and second DCIs.

[0163] As mentioned above, in order to allow the UE to perform UL precoding even if it misses one of these DCIs, each DCI can indicate (sufficient information for use) a basic UL precoder. In other words, in the phase 2 scenario, the basic UL precoder is indicated in each of the two DCIs that schedule the PUSCH.

[0164] There are various options regarding what indications are provided in each of these DCIs. According to the first option, the two DCIs may contain the same set of FD bases and coefficients. In addition to this shared set containing FD bases and coefficients, at least one of the two DCIs may further contain a set containing more detailed indications of FD bases and coefficients (which is different from the shared set of the DCIs containing FD bases and coefficients).

[0165] According to the second option, the two DCIs can contain UL-SB precoding information for FD compression of the same or different layers. Furthermore, at least one of the two DCIs can further contain UL-SB precoding information for FD compression of the remaining layers.

[0166] According to a third option that can help balance the payload between the two DCIs, the first DCI may contain at least some FD-compressed UL SB precoding information, while the second DCI may contain at least a wideband (WB)-TPMI indication and some other FD-compressed UL SB precoding information. For example, the second DCI may contain some differential quantization based on coefficients quantized in the first DCI. In some cases, the second DCI may contain more FD bases and coefficients than those indicated in the first DCI.

[0167] As mentioned above, the potential advantage of each of these options is that if the UE misses one of these DCIs, it can still determine the applicable UL precoding. This enhances the robustness of the two-stage DCI approach.

[0168] In some cases, the third option described above can be extended. For example, in the first DCI, the following can be indicated, where (a) and (b) can always be indicated, while (c) can be optional:

[0169] (a) One or more TPMIs;

[0170] (b) a set containing one or more FD bases associated with TPMI; and

[0171] (c) Some quantification coefficients associated with the one or more TPMIs.

[0172] In some cases, the coefficients in the one or more TPMIs can be treated (as interpreted by the UE) as linear combination coefficients associated with the one or more FD bases. If quantization coefficients associated with the one or more TPMIs are also indicated, these quantization coefficients can have a one-to-one relationship with the nonzero elements of the one or more TPMIs.

[0173] In the second DCI, the WB TPMI (optionally having an additional set of FD bases) may be indicated, along with some more detailed coefficient quantization information associated with the non-zero elements of one or more TPMIs in the first DCI. For example, this more detailed coefficient quantization information may include some differential quantization based on the quantization in the first DCI (optionally also having quantization coefficients associated with the WB TPMI in the second DCI).

[0174] As mentioned above, how the UE performs UL precoding can depend on which DCIs are successfully received. For example, if two DCIs are received, the WB TPMI in the second DCI can be ignored. Alternatively, if two DCIs are received, the WB TPMI in the second DCI can be considered together with the coefficients in the first DCI (if an optional additional set of FD bases in the second DCI is also provided).

[0175] The potential benefit of this extended approach in the third option is that it also guarantees that each DCI itself will provide a basic precoder (although the first DCI may provide better performance than the second DCI), while the first DCI may contain a further reduced load compared to the general third option described above.

[0176] Figure 18 An example of this expansion method is explained, assuming 4 ports and 8 subbands (therefore 8 FD bases to choose from). In this diagram, the k-th FD base is labeled W. f [k], k = 0, 1, ..., 7. The precoder determined based on the two DCIs can have various options. As explained, the information in the second DCI can provide more detailed quantization on top of the TPMI and / or optional quantization in the first DCI. Depending on one option, the precoder P 1aIt is determined based on the information indicated in the first DCI and the refined quantization in the second DCI. In other words, the quantization coefficients in the second DCI can be provided, according to the second option, by the precoder P. 1a +P2 also takes into account the additional precoder information provided in the second DCI (for the independent precoder P2).

[0177] In some cases, each DCI may contain two separate MCS options: one MCS option can be used when the UE receives only a single DCI, while the other MCS option can be used when the UE receives two DCIs.

[0178] In some cases, the first-stage DCI may include an indication of resource allocation and an MCS for the case where the UE receives only a single DCI. In this case, the second-stage DCI may not include resource allocation, but has an MCS for the case where the UE receives two DCIs.

[0179] In the description above, any of the coefficient quantizations described above can be based on at least one of amplitude quantization or phase quantization. For example, in the second proposal (extended third option), when TPMI is provided, only phase quantization can be provided (e.g., this can facilitate constant modulus precoding).

[0180] The methods disclosed herein include one or more steps or actions for implementing the method. These method steps and / or actions may be interchanged 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 may be modified without departing from the scope of the claims.

[0181] As used in this article, the phrase “at least one of” in a list of items refers to any combination of those items, including a single member. As an example, “at least one of a, b, or c” is intended to cover: a, b, c, ab, ac, bc, and abc, as well as any combination with multiple identical elements (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbb, bbc, cc, and ccc, or any other ordering of a, b, and c).

[0182] As used herein, the term "determine" encompasses a wide variety of actions. For example, "determine" can include calculation, computation, processing, derivation, research, searching (e.g., looking in a table, database, or other data structure), ascertaining, and the like. Furthermore, "determine" can include receiving (e.g., receiving information), accessing (e.g., accessing data in memory), and the like. Moreover, "determine" can include parsing, selecting, choosing, building, and the like.

[0183] The preceding description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will readily be understood by those skilled in the art, and the universal principles defined herein may be applied to other aspects. Therefore, the claims are not intended to be limited to the aspects shown herein, but are to be granted the full scope consistent with the language of the claims, wherein references to the singular form of an element are not intended to mean “one and only one” (unless specifically stated otherwise) but “one or more.” Unless specifically stated otherwise, the term “some / a” refers to one or more. All structural and functional equivalents of the aspects described throughout this disclosure that are now or hereafter known to a person skilled in the art are expressly incorporated herein by reference and are intended to be covered by the claims. Furthermore, nothing disclosed herein is intended to be donated to the public, whether or not such disclosure is expressly stated in the claims. No element of a claim should be interpreted in accordance with the provisions of 35 U.S.SC §112(f) unless the element is expressly stated using the phrase “means for…” or, in the case of a method claim, the element is stated using the phrase “steps for…”.

[0184] The various operations of the methods described above can be performed by any suitable means capable of performing the corresponding functions. These means may include various hardware and / or software components and / or modules, including but not limited to circuits, application-specific integrated circuits (ASICs), or processors. For example, Figure 3 The various processors shown can be configured to perform operations 1500 and 1600 of Figures 15 and 16.

[0185] The various illustrative logic blocks, modules, and circuits described in this disclosure can be implemented or executed using a general-purpose processor, digital signal processor (DSP), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA) or other programmable logic device (PLD), discrete gate or transistor logic, discrete hardware components, or any combination thereof, designed to perform the functions described herein. The general-purpose processor may be a microprocessor, but in alternatives, 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, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors cooperating with a DSP core, or any other such configuration.

[0186] If implemented in hardware, an example hardware configuration may include a processing system in a wireless node. The processing system can be implemented using a bus architecture. Depending on the specific application and overall design constraints of the processing system, the bus may include any number of interconnect buses and bridges. The bus can link together various circuits, including a processor, machine-readable media, and a bus interface. The bus interface can be used to connect network adapters, etc., to the processing system via the bus. The network adapter can be used to implement signal processing functions at the PHY layer. In user terminal 120 (see...) Figure 1 In such cases, the user interface (e.g., keypad, display, mouse, joystick, etc.) can also be connected to the bus. The bus can also link various other circuits, such as timing sources, peripherals, voltage regulators, power management circuits, and similar circuits, which are well known in the art and will not be described further. The processor can be implemented using one or more general-purpose and / or special-purpose processors. Examples include microprocessors, microcontrollers, DSP processors, and other circuit systems capable of executing software. Depending on the specific application and the overall design constraints imposed on the system, those skilled in the art will recognize how best to implement the functionality described for the processing system.

[0187] If implemented in software, the functions can be stored or transmitted as one or more instructions or codes on a computer-readable medium. Software should be broadly interpreted to mean instructions, data, or any combination thereof, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. Computer-readable media includes both computer storage media and communication media, encompassing any medium that facilitates the transfer of a computer program from one location to another. The processor may be responsible for managing the bus and general processing, including executing software modules stored on the machine-readable storage medium. The computer-readable storage medium may be coupled to the processor so that the processor can read and write information to / from the storage medium. Alternatively, the storage medium may be integrated into the processor. As an example, the machine-readable medium may include a transmission line, a data-modulated carrier wave, and / or a separate computer-readable storage medium containing instructions stored thereon, all accessible to the processor via a bus interface. Alternatively or additionally, the machine-readable medium or any portion thereof may be integrated into the processor, such as caches and / or general-purpose register files. As an example, examples of machine-readable storage media may include RAM (random access memory), flash memory, ROM (read-only memory), PROM (programmable read-only memory), EPROM (erasable programmable read-only memory), EEPROM (electrically erasable programmable read-only memory), registers, disks, optical disks, hard drives, or any other suitable storage media, or any combination thereof. Machine-readable media may be implemented in computer program products.

[0188] Software modules may comprise a single instruction or a number of instructions, and may be distributed across several different code segments, across different programs, and across multiple storage media. Computer-readable media may include several software modules. These software modules include instructions that, when executed by an instrument (such as a processor), enable the processing system to perform various functions. These software modules may include transfer modules and receive modules. Each software module may reside in a single storage device or be distributed across multiple storage devices. As an example, when a trigger event occurs, a software module may be loaded from a hard drive into RAM. During the execution of a software module, the processor may load some instructions into a cache to improve access speed. One or more cache lines may subsequently be loaded into a general-purpose register file for processor execution. In the context of the functionality of a software module described below, it will be understood that such functionality is implemented by the processor when the processor executes the instructions from that software module.

[0189] Similarly, any connection is also legitimately referred to as computer-readable medium. For example, if 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 technology (such as infrared (IR), radio, and microwave), then that coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technology (such as infrared, radio, and microwave) is included in the definition of medium. As used herein, disks and discs include compact discs (CDs), laser discs, optical discs, digital multi-purpose discs (DVDs), floppy disks, and... Disks, where disks often magnetically reproduce data, and discs optically reproduce data using lasers. Therefore, in some aspects, computer-readable media may include non-transient computer-readable media (e.g., tangible media). Additionally, in other aspects, computer-readable media may include transient computer-readable media (e.g., signals). Combinations of the above should also be included within the scope of computer-readable media.

[0190] Therefore, certain aspects may include computer program products for performing the operations given herein. For example, such computer program products may include computer-readable media on which instructions are stored (and / or encoded) that can be executed by one or more processors to perform the operations described herein (e.g., instructions for performing the operations described herein and illustrated in Figures 15 and 16).

[0191] Furthermore, it should be understood that modules and / or other suitable means for performing the methods and techniques described herein may be downloaded and / or otherwise obtained by the user terminal and / or base station where applicable. For example, such devices can be coupled to a server to facilitate the transfer of means for performing the methods described herein. Alternatively, the various methods described herein can be provided via a storage device (e.g., RAM, ROM, physical storage media such as CDs or floppy disks, etc.) so that the device can obtain the various methods once the storage device is coupled to or provided to the user terminal and / or base station. Furthermore, any other suitable techniques appropriate for providing the methods and techniques described herein to the device may be utilized.

[0192] It will be understood that the claims are not limited to the precise configurations and components described above. Various modifications, substitutions, and variations may be made to the layout, operation, and details of the methods and apparatus described above without departing from the scope of the claims.

Claims

1. A method for wireless communication by a user equipment (UE), comprising: Receive at least one of a first downlink control information (DCI) or a second DCI from a network entity, each DCI indicating at least one set of one or more sets containing one or more frequency domain (FD) bases and linear combination coefficients; In response to receiving only the first DCI, subband precoding is determined based on the first DCI; In response to receiving only the second DCI, subband precoding is determined based on the second DCI; In response to receiving both the first DCI and the second DCI, subband precoding is determined based on the combination of the first DCI and the second DCI; as well as The Physical Uplink Shared Channel (PUSCH) is transmitted via the subband precoding. The first DCI and the second DCI indicate different information.

2. The method of claim 1, wherein: Both the first DCI and the second DCI comprise a common first set containing one or more FD bases and coefficients; and At least one of the first DCI and the second DCI further includes a second set containing one or more FD bases and coefficients, which is different from the common first set containing FD bases and coefficients.

3. The method of claim 1, wherein: The PUSCH is transmitted through multiple transport layers; Both the first DCI and the second DCI include uplink subband precoding information for FD compression of the same or different transport layers among the plurality of transport layers; and At least one of the first DCI and the second DCI further includes uplink subband precoding information for FD compression of one or more of the remaining transport layers of the plurality of transport layers.

4. The method of claim 1, wherein: The first DCI includes at least some FD-compressed uplink subband precoding information; and The second DCI includes at least a wideband transmit precoder matrix indicator (TPMI) and some additional uplink subband precoding information.

5. The method of claim 4, wherein the second DCI comprises differential quantization based on coefficients quantized in the first DCI.

6. The method of claim 5, wherein the quantization is based on at least one of amplitude quantization or phase quantization.

7. The method of claim 4, wherein the second DCI includes one or more FD bases and coefficients that are different from those indicated in the first DCI.

8. The method of claim 4, wherein: The first DCI indicates at least one or more TPMIs and one or more sets containing FD bases associated with the TPMIs; and The coefficients in the one or more TPMIs are treated as the linear combination coefficients associated with the one or more FD bases.

9. The method of claim 8, wherein: The first DCI also indicates at least some quantization coefficients associated with the one or more TPMIs; and The quantization coefficient can have a one-to-one association with the non-zero elements of one or more TPMIs.

10. The method of claim 1, wherein the first DCI and the second DCI each indicate different modulation and coding scheme (MCS) options: one MCS option for the case where only a single DCI is received, and another MCS option for the case where both the first DCI and the second DCI are received.

11. The method of claim 1, wherein: One of the first DCI or the second DCI indicates resource allocation and MCS for cases where only a single DCI is received; and The first DCI or the other of the second DCI does not indicate resource allocation, but has an MCS for the case where both the first DCI and the second DCI are received.

12. A method for wireless communication by a network entity, comprising: At least a first downlink control information (DCI) and a second DCI are sent to the user equipment (UE), each DCI indicating at least one set of one or more sets containing one or more frequency domain (FD) bases and linear combination coefficients; as well as Process the Physical Uplink Shared Channel (PUSCH) transmitted from the UE via subband precoding based on the first DCI, the second DCI, or a combination of the first DCI and the second DCI. The first DCI and the second DCI indicate different information.

13. The method of claim 12, wherein: Both the first DCI and the second DCI comprise a common first set containing one or more FD bases and coefficients; and At least one of the first DCI and the second DCI further includes a second set containing one or more FD bases and coefficients, which is different from the common first set containing FD bases and coefficients.

14. The method of claim 12, wherein: The PUSCH is transmitted through multiple transport layers; Both the first DCI and the second DCI include uplink subband precoding information for FD compression of the same or different transport layers among the plurality of transport layers; and At least one of the first DCI and the second DCI further includes uplink subband precoding information for FD compression of one or more of the remaining transport layers of the plurality of transport layers.

15. The method of claim 12, wherein: The first DCI includes at least some FD-compressed uplink subband precoding information; and The second DCI includes at least a wideband transmit precoder matrix indicator (TPMI) and some additional uplink subband precoding information.

16. The method of claim 15, wherein: The first DCI indicates at least one or more TPMIs and one or more sets containing FD bases associated with the TPMIs; and The coefficients in the one or more TPMIs are treated as the linear combination coefficients associated with the one or more FD bases.

17. The method of claim 16, wherein: The first DCI also indicates at least some quantization coefficients associated with the one or more TPMIs; and The quantization coefficient can have a one-to-one association with the non-zero elements of one or more TPMIs.

18. The method of claim 16, wherein the additional uplink subband precoding information in the second DCI includes an additional set of FD bases.

19. The method of claim 16, wherein the additional uplink subband precoding information in the second DCI includes additional coefficient quantization information associated with non-zero elements of the one or more TPMIs in the first DCI.

20. The method of claim 19, wherein the additional coefficient quantization information is based on at least one of amplitude quantization or phase quantization.

21. The method of claim 19, wherein the additional coefficient quantization information includes only phase quantization.

22. The method of claim 19, wherein the additional coefficient quantization information indicates differential quantization based on quantization in the first DCI.

23. The method of claim 22, wherein the additional coefficient quantization information indicates the quantization coefficients associated with the broadband TPMI in the second DCI.

24. The method of claim 12, wherein the first DCI and the second DCI each indicate different modulation and coding scheme (MCS) options: one MCS option for the case where only a single DCI is received, and another MCS option for the case where both the first DCI and the second DCI are received.

25. The method of claim 12, wherein: One of the first DCI or the second DCI indicates resource allocation and MCS for cases where only a single DCI is received; and The first DCI or the other of the second DCI does not indicate resource allocation, but has an MCS for the case where both the first DCI and the second DCI are received.

26. An apparatus for wireless communication, comprising: Memory; as well as At least one processor coupled to the memory, the processor being configured to: Receive at least one of a first downlink control information (DCI) or a second DCI from a network entity, each DCI indicating at least one set of one or more sets containing one or more frequency domain (FD) bases and linear combination coefficients; Subband precoding is determined based on the first DCI, the second DCI, or a combination of the first DCI and the second DCI, depending on whether the first DCI, the second DCI, or both are received. as well as The Physical Uplink Shared Channel (PUSCH) is transmitted via the subband precoding. The first DCI and the second DCI indicate different information.

27. The apparatus of claim 26, wherein: Both the first DCI and the second DCI comprise a common first set containing one or more FD bases and coefficients; and At least one of the first DCI and the second DCI further includes a second set containing one or more FD bases and coefficients, which is different from the common first set containing FD bases and coefficients.

28. The apparatus of claim 26, wherein: The PUSCH is transmitted through multiple transport layers; Both the first DCI and the second DCI include uplink subband precoding information for FD compression of the same or different transport layers among the plurality of transport layers; and At least one of the first DCI and the second DCI further includes uplink subband precoding information for FD compression of one or more of the remaining transport layers of the plurality of transport layers.

29. The apparatus of claim 26, wherein: The first DCI includes at least some FD-compressed uplink subband precoding information; and The second DCI includes at least a wideband transmit precoder matrix indicator (TPMI) and some additional uplink subband precoding information.

30. The apparatus of claim 29, wherein the second DCI comprises differential quantization based on coefficients quantized in the first DCI.

31. The apparatus of claim 30, wherein the quantization is based on at least one of amplitude quantization or phase quantization.

32. The apparatus of claim 29, wherein the second DCI includes one or more FD bases and coefficients that are different from those indicated in the first DCI.

33. The apparatus of claim 29, wherein: The first DCI indicates at least one or more TPMIs and one or more sets containing FD bases associated with the TPMIs; and The coefficients in the one or more TPMIs are treated as the linear combination coefficients associated with the one or more FD bases.

34. The apparatus of claim 33, wherein: The first DCI also indicates at least some quantization coefficients associated with the one or more TPMIs; and The quantization coefficient can have a one-to-one association with the non-zero elements of one or more TPMIs.

35. The apparatus of claim 26, wherein the first DCI and the second DCI each indicate different modulation and coding scheme (MCS) options: one MCS option for the case where only a single DCI is received, and another MCS option for the case where both the first DCI and the second DCI are received.

36. The apparatus of claim 26, wherein: One of the first DCI or the second DCI indicates resource allocation and MCS for cases where only a single DCI is received; and The first DCI or the other of the second DCI does not indicate resource allocation, but has an MCS for the case where both the first DCI and the second DCI are received.

37. An apparatus for wireless communication, comprising: Memory; as well as At least one processor coupled to the memory, the processor being configured to: At least a first downlink control information (DCI) and a second DCI are sent to the user equipment (UE), each DCI indicating at least one set of one or more sets containing one or more frequency domain (FD) bases and linear combination coefficients; as well as Process the Physical Uplink Shared Channel (PUSCH) transmitted from the UE via subband precoding based on the first DCI, the second DCI, or a combination of the first DCI and the second DCI. The first DCI and the second DCI indicate different information.

38. The apparatus of claim 37, wherein: Both the first DCI and the second DCI comprise a common first set containing one or more FD bases and coefficients; and At least one of the first DCI and the second DCI further includes a second set containing one or more FD bases and coefficients, which is different from the common first set containing FD bases and coefficients.

39. The apparatus of claim 37, wherein: The PUSCH is transmitted through multiple transport layers; Both the first DCI and the second DCI include uplink subband precoding information for FD compression of the same or different transport layers among the plurality of transport layers; and At least one of the first DCI and the second DCI further includes uplink subband precoding information for FD compression of one or more of the remaining transport layers of the plurality of transport layers.

40. The apparatus of claim 37, wherein: The first DCI includes at least some FD-compressed uplink subband precoding information; and The second DCI includes at least a wideband transmit precoder matrix indicator (TPMI) and some additional uplink subband precoding information.

41. The apparatus of claim 40, wherein: The first DCI indicates at least one or more TPMIs and one or more sets containing FD bases associated with the TPMIs; and The coefficients in the one or more TPMIs are treated as the linear combination coefficients associated with the one or more FD bases.

42. The apparatus of claim 41, wherein: The first DCI also indicates at least some quantization coefficients associated with the one or more TPMIs; and The quantization coefficient can have a one-to-one association with the non-zero elements of one or more TPMIs.

43. The apparatus of claim 41, wherein the additional uplink subband precoding information in the second DCI includes an additional set of FD bases.

44. The apparatus of claim 41, wherein the additional uplink subband precoding information in the second DCI includes additional coefficient quantization information associated with non-zero elements of the one or more TPMIs in the first DCI.

45. The apparatus of claim 44, wherein the additional coefficient quantization information is based on at least one of amplitude quantization or phase quantization.

46. ​​The apparatus of claim 44, wherein the additional coefficient quantization information comprises only phase quantization.

47. The apparatus of claim 44, wherein the additional coefficient quantization information indicates differential quantization based on quantization in the first DCI.

48. The apparatus of claim 47, wherein the additional coefficient quantization information indicates quantization coefficients associated with the broadband TPMI in the second DCI.

49. The apparatus of claim 37, wherein the first DCI and the second DCI each indicate different modulation and coding scheme (MCS) options: one MCS option for the case where only a single DCI is received, and another MCS option for the case where both the first DCI and the second DCI are received.

50. The apparatus of claim 37, wherein: One of the first DCI or the second DCI indicates resource allocation and MCS for cases where only a single DCI is received; and The first DCI or the other of the second DCI does not indicate resource allocation, but has an MCS for the case where both the first DCI and the second DCI are received.

51. An apparatus for wireless communication, comprising: A means for receiving at least one of a first downlink control information (DCI) or a second DCI from a network entity, each DCI indicating at least one set of one or more sets containing one or more frequency domain (FD) bases and linear combination coefficients; A means for determining subband precoding based on the first DCI, the second DCI, or a combination of the first DCI and the second DCI, depending on whether the first DCI, the second DCI, or both the first DCI and the second DCI are received; as well as A means for transmitting the Physical Uplink Shared Channel (PUSCH) via the subband precoding, The first DCI and the second DCI indicate different information.

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