Pmi configuration

Abstract

Example embodiments of the present disclosure relate to precoding matrix indicator (PMI) configuration. In one method, a first apparatus receives configuration information of a plurality of codebooks from a second apparatus. The codebooks include a set of PMIs. The first apparatus also receives an indication from the second apparatus that a determination of channel state information (CSI) is based on a second codebook of the plurality of codebooks instead of a first codebook previously used. The first apparatus receives at least one CSI reference signal (RS) from the second apparatus. The at least one CSI RS is transmitted via a uniform beam on at least one antenna port. The first apparatus determines at least one CSI quantity of at least one PMI indicated by the second codebook for at least one layer based on the at least one CSI RS.

Description

Cross-references to related applications

[0001] This application claims priority and benefit to U.S. Provisional Application No. 63 / 793848, filed April 24, 2025, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0002] Various exemplary embodiments of this disclosure generally relate to the telecommunications field, and more specifically to methods, apparatuses, devices, and computer-readable storage media for configuring precoded matrix indicators (PMIs). Background Technology

[0003] A communication network can be used as a facility to enable communication between two or more communication devices or to provide communication devices with access to a data network. A mobile or wireless communication network is an example of a communication network. Services can be provided to communication devices by an application server.

[0004] Communication networks can operate according to standards provided by organizations such as the 3rd Generation Partnership Project (3GPP) or the European Telecommunications Standards Institute (ETSI). Examples of standards provided by 3GPP are the so-called 3GPP standards used for generations of cellular technology, such as the 3GPP standards for 4G, 5G, 6G, etc. Summary of the Invention

[0005] In a first aspect of this disclosure, a first apparatus is provided. The first apparatus includes: at least one processor; and at least one memory storing instructions, which, when executed by the at least one processor, cause the first apparatus to: receive configuration information of a plurality of codebooks from a second apparatus, the codebooks including a set of precoded matrix indicators (PMIs); receive from the second apparatus an indication that the determination of channel state information (CSI) is based on a second codebook among the plurality of codebooks rather than a previously used first codebook; receive from the second apparatus at least one CSI reference signal (RS), the at least one CSI RS being transmitted via a uniform beam at at least one antenna port; and determine, based on the at least one CSI RS, at least one CSI quantity of at least one PMI indicated by the second codebook for at least one layer.

[0006] In a second aspect of this disclosure, a second apparatus is provided. The second apparatus includes: at least one processor; and at least one memory storing instructions, which, when executed by the at least one processor, cause the second apparatus to: transmit configuration information of a plurality of codebooks to a first apparatus, the codebooks including a set of precoded matrix indicators (PMIs); transmit to the first apparatus an indication that the determination of channel state information (CSI) is based on a second codebook among the plurality of codebooks rather than a previously used first codebook; transmit at least one CSI reference signal (RS) to the first apparatus, the at least one CSI RS being transmitted via a uniform beam at at least one antenna port; and receive from the first apparatus at least one CSI quantity of at least one PMI indicated by the second codebook for at least one layer.

[0007] In a third aspect of this disclosure, a method is provided. The method includes: receiving configuration information of a plurality of codebooks from a second device at a first device, the codebooks including a set of precoding matrix indicators (PMIs); receiving from the second device an indication of channel state information (CSI) determined based on a second codebook among the plurality of codebooks rather than a previously used first codebook; receiving from the second device at least one CSI reference signal (RS), the at least one CSI RS being transmitted via a uniform beam at at least one antenna port; and determining at least one CSI quantity based on the at least one CSI RS for at least one PMI indicated by the second codebook for at least one layer.

[0008] In a fourth aspect of this disclosure, a method is provided. The method includes: transmitting configuration information of a plurality of codebooks, including a set of precoding matrix indicators (PMIs), from a second device to a first device; transmitting to the first device an indication that the determination of channel state information (CSI) is based on a second codebook among the plurality of codebooks rather than a previously used first codebook; transmitting to the first device at least one CSI reference signal (RS), the at least one CSI RS being transmitted via a uniform beam at at least one antenna port; and receiving from the first device at least one CSI quantity of at least one PMI indicated by the second codebook for at least one layer.

[0009] In a fifth aspect of this disclosure, a first apparatus is provided. The first apparatus includes: means for receiving configuration information of a plurality of codebooks from a second apparatus, the codebooks including a set of precoding matrix indicators (PMIs); means for receiving an indication of channel state information (CSI) from the second apparatus based on a second codebook among the plurality of codebooks rather than a previously used first codebook; means for receiving at least one CSI reference signal (RS) from the second apparatus, the at least one CSI RS being transmitted via a uniform beam at at least one antenna port; and means for determining at least one CSI quantity of at least one PMI indicated by the second codebook for at least one layer based on the at least one CSI RS.

[0010] In a sixth aspect of this disclosure, a second apparatus is provided. The second apparatus includes: means for transmitting configuration information of a plurality of codebooks to a first apparatus, the codebooks including a set of precoding matrix indicators (PMIs); means for transmitting to the first apparatus an indication that the determination of channel state information (CSI) is based on a second codebook among the plurality of codebooks rather than a previously used first codebook; means for transmitting to the first apparatus at least one CSI reference signal (RS), the at least one CSI RS being transmitted via a uniform beam at at least one antenna port; and means for receiving from the first apparatus at least one CSI quantity of at least one PMI indicated by the second codebook for at least one layer.

[0011] In a seventh aspect of this disclosure, a computer-readable medium is provided. The computer-readable medium includes instructions stored thereon for causing a device to at least execute the method according to a third aspect.

[0012] In an eighth aspect of this disclosure, a computer-readable medium is provided. The computer-readable medium includes instructions stored thereon for causing a device to at least execute the method according to the fourth aspect.

[0013] It should be understood that the summary portion is not intended to identify key or essential features of the embodiments of this disclosure, nor is it intended to limit the scope of this disclosure. Other features of this disclosure will become readily apparent from the following description. Attached Figure Description

[0014] Some exemplary embodiments will now be described with reference to the accompanying drawings, in which: Figure 1A An example architecture for downlink (DL) multiple-input multiple-output (MIMO) based on codebook (CB) is shown; Figure 1B An example architecture of DL MIMO based on probe reference signal (SRS) is shown; Figure 2 An example communication environment in which example embodiments of the present disclosure may be implemented is shown; Figure 3 Example signaling flows for PMI configuration are shown according to some example embodiments of this disclosure; Figure 4 An example diagram of gNB beam to PMI mapping is shown; Figure 5 Example signaling flows for CB-based PMI configuration are shown according to some example embodiments of this disclosure; Figure 6 Example diagrams illustrating gNB beam-to-PMI mapping with multiple CBs are shown according to some exemplary embodiments of the present disclosure; Figure 7 Another example signaling flow for PMI configuration is shown according to some example embodiments of this disclosure; Figure 8 A flowchart is shown illustrating a method implemented at a first device according to some exemplary embodiments of the present disclosure; Figure 9 A flowchart is shown illustrating a method implemented at a second device according to some example embodiments of the present disclosure; Figure 10 A flowchart is shown of another method implemented at a first device according to some example embodiments of the present disclosure; Figure 11 A flowchart is shown of another method implemented at a second device according to some example embodiments of the present disclosure; Figure 12 A simplified block diagram of a device suitable for implementing example embodiments of the present disclosure is shown; and Figure 13 A block diagram of an example computer-readable medium according to some example embodiments of the present disclosure is shown.

[0015] In all the accompanying drawings, the same or similar reference numerals denote the same or similar elements. Detailed Implementation

[0016] The principles of this disclosure will now be described with reference to some exemplary embodiments. It should be understood that these embodiments are described for illustrative purposes only and to assist those skilled in the art in understanding and implementing this disclosure, and do not imply any limitation on the scope of this disclosure. The embodiments described herein can be implemented in various ways other than those described below.

[0017] In the following description and claims, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains.

[0018] References to "an embodiment," "embodiment," "example embodiment," etc., in this disclosure indicate that the described embodiment may include a particular feature, structure, or characteristic, but not every embodiment must include that particular feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Moreover, when a particular feature, structure, or characteristic is described in connection with an embodiment, whether explicitly described or not, it is believed that its influence on such feature, structure, or characteristic in conjunction with other embodiments is within the knowledge of those skilled in the art.

[0019] It should be understood that although various elements may be described herein using prefixes such as “first,” “second,” etc., these elements should not be limited by these terms. These terms are used only to distinguish one element from another, and they do not restrict the order of the terms. For example, without departing from the scope of the exemplary embodiments, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element. As used herein, the term “and / or” includes any and all combinations of one or more of the listed terms.

[0020] As used herein, “at least one of the following: a list of two or more elements” and “at least one of the following: a list of two or more elements” and similar wording (where the list of two or more elements is connected by “and” or “or”) means at least any one of the elements, or at least any two or more of the elements, or at least all of the elements.

[0021] As used herein, unless explicitly stated otherwise, the execution step “in response to A” does not indicate that the step is performed immediately after “A” occurs, and may include one or more intermediate steps.

[0022] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that, when used herein, the terms “comprises,” “comprising,” “has,” “having,” “includes,” and / or “including” specify the presence of the stated features, elements, and / or components, but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof.

[0023] As used in this application, the term "circuit system" may refer to one or more of the following: (a) Hardware circuit implementation only (such as implementation in analog and / or digital circuits only) and (b) A combination of hardware circuitry and software, such as (if applicable): (i) A combination of (multiple) analog and / or digital hardware circuits and software / firmware, and (ii) Any part of a hardware processor(s) with software (including (multiple) digital signal processors, software, and (multiple) memories, which work together to enable a device (such as a mobile phone or server) to perform various functions), and (c) (Multiple) hardware circuits and / or (multiple) processors, such as (multiple) microprocessors or a portion thereof, which require software (e.g. firmware) to operate, but may not exist when the software is not required to operate.

[0024] The definition of "circuit system" applies to all uses of the term in this application, including any claim. As yet another example, as used in this application, the term "circuit system" also covers implementations of hardware circuitry or processors (or processors) or hardware circuitry or processors and their accompanying software and / or firmware. The term "circuit system" also covers, for example (and if applicable to a particular claim element), baseband integrated circuits or processor integrated circuits for mobile devices or similar integrated circuits in servers, cellular network devices, or other computing or networking devices.

[0025] As used herein, the term "communication network" refers to a network that conforms to any suitable communication standard, such as New Radio (NR), Long Term Evolution (LTE), LTE-A Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA), High-Speed ​​Packet Access (HSPA), Narrowband Internet of Things (NB-IoT), etc. Furthermore, communication between terminal devices and network devices in the communication network can be performed according to any suitable generation of communication protocol, including but not limited to first-generation (1G), second-generation (2G), 2.5G, 2.75G, third-generation (3G), fourth-generation (4G), 4.5G, fifth-generation (5G), sixth-generation (6G) communication protocols and / or any other currently known or future-developed protocols. Embodiments of this disclosure can be applied to a variety of communication systems. Given the rapid development of communications, there will certainly be future types of communication technologies and systems that embody the future types of this disclosure. The scope of this disclosure should not be construed as limited to the aforementioned systems.

[0026] As used herein, the term "network device" refers to a node in a communications network through which terminal devices access the network and receive services. Depending on the terminology and technology applied, a network device can refer to a base station (BS) or access point (AP), such as a Node B (NodeB or NB), an evolved Node B (eNodeB or eNB), an NR NB (also known as a gNB), a Remote Radio Unit (RRU), a Radio Header (RH), a Remote Radio Header End (RRH), a relay, an Integrated Access and Backhaul (IAB) node, a low-power node (such as a femto, pico, or non-terrestrial network (NTN)) or non-terrestrial network equipment (such as satellite network equipment), low Earth orbit (LEO) satellites and geostationary Earth orbit (GEO) satellites, spacecraft network equipment, etc. In some example embodiments, the Radio Access Network (RAN) split architecture includes a centralized unit (CU) and a distributed unit (DU) at the IAB donor node. The IAB node includes a mobile terminal (IAB-MT) portion that behaves as a UE facing the parent node, and the DU portion of the IAB node behaves as a base station facing the next-hop IAB node.

[0027] As used herein, the term "network device" can also refer to a core network (CN) entity / node / function / device / equipment. An example core network node may include one or more of the following functions: Location Management Function (LMF), Mobile Switching Center (MSC), Mobility Management Entity (MME), Home Subscriber Server (HSS), Access and Mobility Management Function (AMF), Session Management Function (SMF), Authentication Server Function (AUSF), Subscription Identifier Dehiding Function (SIDF), Unified Data Management (UDM), Security Edge Protection Agent (SEPP), Network Exposure Function (NEF), and / or User Plane Function (UPF).

[0028] The term "terminal device" refers to any terminal device capable of wireless communication. As an example and not a limitation, a terminal device may also be referred to as a communication device, user equipment (UE), subscriber station (SS), portable subscriber station, mobile station (MS), or access terminal (AT). Terminal devices may include, but are not limited to, mobile phones, cellular phones, smartphones, Voice over IP (VoIP) phones, wireless local loop phones, tablet computers, wearable terminal devices, personal digital assistants (PDAs), portable computers, desktop computers, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback devices, in-vehicle wireless terminal devices, wireless endpoints, mobile stations, laptop embedded devices (LEEs), laptop mounted devices (LMEs), USB dongles, smart devices, wireless customer premises equipment (CPEs), Internet of Things (IoT) devices, watches or other wearable devices, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in the context of industrial and / or automated processing chains), consumer electronics devices, devices operating on commercial and / or industrial wireless networks, etc. The terminal equipment may also correspond to the mobile termination (MT) portion of an IAB node (e.g., a relay node). In the following description, the terms "terminal equipment," "communication equipment," "terminal," "user equipment," and "UE" are used interchangeably.

[0029] As used herein, the terms “resource,” “transmission resource,” “resource block,” “physical resource block” (PRB), “uplink resource,” or “downlink resource” can refer to any resource used to perform communication, such as communication between a terminal device and a network device, including resources in the time domain, frequency domain, spatial domain, code domain, or any other combination of time, frequency, spatial, and / or code domain resources used to implement communication. In the following, unless explicitly stated otherwise, resources in the frequency and time domains will be used as examples of transmission resources used to describe some exemplary embodiments of this disclosure. Note that the exemplary embodiments of this disclosure are equally applicable to other resources in other domains.

[0030] In some mechanisms, such as DL MIMO, MIMO is supported by various communication networks. Figure 1AAn example architecture 100 for a DL MIMO process based on advanced CB is illustrated. As shown, gNB 120 transmits multiple Type 1 Channel State Information (CSI) Reference Signals (RS) from a uniform beam (i.e., beams with the same antenna characteristics but different phase centers), such as four or more Type 1 CSI RSs. The number of antenna ports (APs) used at gNB 120 depends on the gNB implementation and / or the current load of gNB 120. UE 110 receives these CSI RSs on all supported DL UE antenna ports and derives an H matrix and a PMI, which informs gNB 120 of the optimal precoding seen by UE 110 for DL ​​data transmission. gNB 120 can choose to use the PMI derived by UE 110 or use a different PMI based on its knowledge of the channel between gNB 120 and UE 110.

[0031] One mechanism by which the gNB 120 obtains this channel knowledge is by initiating SRS-based DL MIMO, such as... Figure 1B The example architecture 150 is shown. As shown, gNB 120 sends SRS allocation to UE 110. UE 110 sends SRS to gNB 120 from each UE AP with UL capability. gNB 120 receives SRS via uniform beaming on 4 or more APs and derives optimal precoding. gNB 120 configures the precoded DL transmission beam. UE 110 receives DL data transmission on one or more precoded or unprecoded UE APs.

[0032] However, even though SRS-based DL MIMO procedures are more accurate than CSI-RS procedures because they do not rely on predefined PMI values ​​derived by the UE, they do require additional signaling overhead from the UE for the desired SRS transmission format. Furthermore, SRS-based procedures have limited scope compared to CSI-RS-based procedures because the UL link budget is typically worse than the DL link budget, and a larger number of SRS transmissions increases the risk of inter-cell interference.

[0033] The size of the H matrix between the gNB and the UE depends on the number of APs used at both the gNB and the UE. While the number of APs at the UE is limited to 4 for handheld devices, the number of APs at the gNB can be any number from 4 to the maximum number of APs supported at the gNB. For 5G, the maximum number is 32, but for 6G, the maximum number is expected to increase to 64, 128, or even 256. Therefore, the H matrix will become very large, requiring complex, time-consuming, and power-intensive calculations to derive the optimal PMI value for a given channel condition. The PMI can be derived in many ways, some requiring more computational complexity or power to improve accuracy, and two of these methods are summarized below. However, it should be remembered that this depends on the UE implementation and is therefore not directly specified within 3GPP. This means that the method used to derive the PMI value at the UE is unknown for a gNB with Type 1 CB DL MIMO.

[0034] Singular Value Decomposition (SVD) is a fundamental mathematical tool that plays a crucial role in enhancing the performance of MIMO systems. This section delves into the applications of SVD in channel estimation and precoding, highlighting its benefits for maximizing data rate and mitigating interference.

[0035] In MIMO, accurate channel estimation is crucial for efficient data transmission. Direct estimation of the channel matrix, which represents the complex propagation characteristics between the base station and user equipment antennas, can be challenging. SVD provides a robust solution by decomposing the channel matrix into three matrices: U: Left singular vector, representing the direction of the maximum variance in the received signal.

[0036] ∑: A diagonal matrix containing singular values, indicating the strength of different signal paths.

[0037] V: Right singular vector, representing the direction of the maximum variance in the transmitted signal.

[0038] SVD simplifies channel estimation by focusing on estimating singular values ​​and vectors, which are generally simpler to process than the entire channel matrix. This approach reduces computational complexity and supports efficient estimation algorithms.

[0039] Precoding aims to optimize the transmitted signal to maximize the data rate and minimize interference in MIMO systems. Singular Vector Decomposition (SVD) plays a crucial role in designing the optimal precoding matrix. The right singular vector (V) from the channel matrix decomposition provides information about the direction of maximum signal strength. By aligning the signal with the strongest path, precoding increases the signal-to-noise ratio (SNR), resulting in a higher data rate. Furthermore, precoding minimizes interference between different data streams transmitted through the MIMO channel.

[0040] One drawback of the simple SVD method is that it does not include interference when deriving the singular vector for optimal power, and therefore may not find the optimal PMI for the best signal-to-interference-noise ratio (SINR).

[0041] The UE can convolve each predefined PMI value onto the H matrix to derive the SINR for all possible PMI values. This ensures the UE will find the optimal PMI value for the best SINR used in the MIMO layer. However, this method is computationally very intensive and may not be suitable for all UEs. For example, for a gNB with 32 APs and a UE with 4 APs, a phase granularity of 90° will produce a 32x4 H matrix and a SINR of 4.6 at the gNB. 18 There are only 256 unique beam configurations (PMI values), which is an unrealistic number that the UE has to deal with. Most of these unique beam configurations will not result in any significant gain increase compared to other PMI configurations, and the gNB rarely uses more than 256 PMI configurations (codebooks). The gNB codebook is known to the UE, and it can limit the exhaustive PMI search to those PMI values. However, a significant amount of processing time is still required at the UE. Therefore, it is expected that the gNB can help the UE perform accurate estimation of the optimal PMI without a very heavy computational process.

[0042] According to some example embodiments of this disclosure, a solution for PMI configuration is provided. In this solution, a second device, such as a network device, sends configuration information of a CSI report to a first device, such as a terminal device. This configuration information indicates multiple PMIs. The second device also sends a configuration of a subset of the multiple PMIs to the first device. The second device also sends at least one CSI RS to the first device via a uniform beam at at least one antenna port. The first device determines at least one CSI amount for a subset of PMIs for at least one layer based on the configuration and the at least one CSI RS. In this way, the second device can configure the first device to determine the CSI amount for a subset of PMIs rather than all PMIs. The subset of PMIs can be identified by the second device as the preferred PMIs most likely to result in the optimal SINR for the DL MIMO layer. The calculations used to derive the optimal PMI from the complete codebook can be reduced, especially in the case of a large number of antenna ports.

[0043] The exemplary embodiments of this disclosure will now be described in detail with reference to the accompanying drawings. Figure 2 An example communication environment 200 in which exemplary embodiments of the present disclosure may be implemented is shown. The communication environment 200 includes a first device 210 and a second device 220.

[0044] In some solutions, the second device 220 can provide one or more service areas for the first device 210. The service area provided by the second device 220 may be referred to as a cell (not shown).

[0045] In some example embodiments, the first device 210 may be implemented as a terminal device or included in a terminal device, and the second device 220 may be implemented as a network device serving the terminal device or included in a network device serving the terminal device.

[0046] In the following description, for illustrative purposes, some exemplary embodiments are depicted in which the first device 210 operates as a terminal device and the second device 220 operates as a network device. However, in some exemplary embodiments, the operations described in connection with the terminal device can be implemented at the network device or other devices, and the operations described in connection with the network device can be implemented at the terminal device or other devices.

[0047] In some example embodiments, if the first device 210 is a terminal device and the second device 220 is a network device, the direction from the second device 220 to the first device 210 is referred to as the downlink (DL), and the direction from the first device 210 to the second device 220 is referred to as the uplink (UL). In the DL, the second device 220 is a transmitting (TX) device (or transmitter), and the first device 210 is a receiving (RX) device (or receiver). In the UL, the first device 210 is a TX device (or transmitter), and the second device 220 is an RX device (or receiver).

[0048] It should be understood that Figure 2 The number of devices and their connections shown are for illustrative purposes only and do not imply any limitation. Communication environment 200 may include any suitable number of devices configured to implement the exemplary embodiments of this disclosure. Although not shown, it will be understood that one or more additional devices or apparatuses may be located in a cell provided by second device 220, and one or more additional cells may be deployed in communication environment 200.

[0049] Communication in communication environment 200 can be implemented according to any suitable communication protocol(s), including but not limited to cellular communication protocols such as first-generation (1G), second-generation (2G), third-generation (3G), fourth-generation (4G), fifth-generation (5G), 5.5G, and sixth-generation (6G), wireless local network communication protocols such as IEEE 802.11, and / or any other currently known or future-developed protocols. Furthermore, communication can utilize any suitable wireless communication technology, including but not limited to: Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Frequency Division Duplex (FDD), Time Division Duplex (TDD), Multiple-Input Multiple-Output (MIMO), Orthogonal Frequency Division Multiple Access (OFDM), Discrete Fourier Transform Extended OFDM (DFT-s-OFDM), and / or any other currently known or future-developed technologies.

[0050] Figure 3 An example signaling flow 300 for PMI configuration is shown according to some example embodiments of this disclosure. Signaling flow 300 relates to... Figure 2 The first device 210 and the second device 220 in the middle.

[0051] In operation, the second device 220 sends (3010) configuration information of a CSI report to the first device 210. The configuration information indicates multiple PMIs (also referred to as the entire PMI set). Accordingly, the first device 210 receives (3015) configuration information. For example, the configuration information may be included in a Radio Resource Control (RRC) configuration or any other suitable message or signaling.

[0052] The second device 220 sends (3030) the configuration of a subset of PMIs to the first device 210. Multiple PMIs include at least a subset of PMIs. That is, a subset of PMIs is a subset of multiple PMIs or a subset of the entire set of PMIs. Accordingly, the first device 210 receives (3035) the configuration of the subset of PMIs. As an example, this configuration may include at least one of the following: Downlink Control Information (DCI), Media Access Control Element (MAC CE), or any other suitable message or signaling.

[0053] The second device 220 transmits (3040) at least one CSI RS to the first device 210 via a uniform beam at at least one antenna port. For example, multiple CSI RSs are transmitted on multiple antenna ports. Each CSI RS is transmitted from a corresponding individual antenna port. The first device 210 receives (3045) at least one CSI RS. The first device 210 determines (3050) at least one CSI quantity for a subset of PMIs for at least one layer based on the configuration and at least one CSI RS. As used herein, the CSI quantity (also referred to as a CSI parameter) may include, but is not limited to, Reference Signal Received Power (RSRP), SRS Resource Indicator (SRI), Rank Indicator (RI), Channel Quality Indicator (CQI), etc. The CSI quantity or CSI value may be linked to a PMI selected from the subset of PMIs. At least one layer may include each DL MIMO layer.

[0054] Then, the first device 210 may send (3060) the determined CSI quantity for at least one subset of PMIs for at least one layer to the second device 220. Accordingly, the second device 220 receives (3065) the at least one CSI quantity for at least one subset of PMIs for at least one layer. The at least one CSI quantity may be included in uplink control information (UCI), CSI reports, etc.

[0055] In some example embodiments, the first device 210 may select a PMI for at least one layer from a plurality of PMIs using SVD, a full exhaustive scheme, or a scheme specific to the first device 210. The first device 210 may send at least one CSI quantity of the selected PMI for the at least one layer to the second device 220.

[0056] The second device 220 may receive from the first device 210 at least one CSI value of the PMI selected by the first device 210 for at least one layer. The second device 220 may determine a subset of PMIs based at least on the at least one CSI value of the PMIs selected by the first device 210. For example, the second device 220 may determine at least one adjacent beam and at least one corresponding PMI based on at least one of the following: MIMO type, cell load, subband precoding requirements, or at least one CSI value of the PMIs selected by the first device 210, wherein the subset of PMIs includes at least one corresponding PMI. The selection of PMI values ​​to be included in the subset of PMIs may be based on optimal power delivery or optimal SINR, which is based on MIMO type (e.g., single-user (SU)-MIMO or multi-user (MU)-MIMO), cell load, and / or subband precoding requirements. The second device 220 may then send (3030) the configuration of the subset of PMIs to the first device 210. In this way, the second device 220 can identify the preferred set of PMIs that are most likely to result in the optimal SINR for the DL MIMO layer.

[0057] In some example embodiments, the configuration information in the CSI report may include a first codebook indicating multiple PMIs. The first codebook may be a full Type 1 codebook for DL ​​MIMO or any other suitable codebook. A subset of PMIs may include at least one PMI indicated by the first codebook, such as a portion of the first codebook.

[0058] Alternatively, a subset of the PMI can be indicated by a second codebook. The second codebook can be associated with a second resolution higher than the first resolution associated with the first codebook. For example, the second codebook could be a codebook with a resolution higher than that of the full type 1 codebook.

[0059] In some example embodiments, the configuration of the PMI subset can indicate the duration for determining the CSI for the PMI subset. The first device 210 can determine (3050) at least one CSI quantity for the PMI subset during this duration. That is, the network can replace the normal DL MIMO procedure by instructing the first device 210 to evaluate only a subset of PMI values ​​for a given time based on the channel coherence.

[0060] In some example embodiments, the first device 210 may send capability information of the first device 210 to the second device 220, the capability information indicating support for CSI assessment for a subset of PMIs. Accordingly, the second device 220 may receive the capability information of the first device 210. If the first device 210 supports CSI assessment for a subset of PMIs, the second device 220 may configure the PMI subset for the first device 210.

[0061] Since each MIMO layer is linked to a cluster in the channel, the most likely next best gNB beam (PMI update) is usually the beam adjacent to the currently best configured gNB beam (current PMI value), especially if the PMI update is triggered or required by the movement of the first device 210. Figure 4 Example diagram 400 shows a gNB beam to PMI mapping. Assume that the currently used PMI value 410 is a beam with index #34, and at least one adjacent gNB beam configuration for this beam configuration can be represented by PMI#2, PMI#3, PMI#33, PMI#34, PMI#66, and PMI#67.

[0062] The first device 210 can omit the adjacent gNB beam prediction because it is unaware of the AP-to-physical antenna mapping at the second device 220 (which will differ between different gNBs), and therefore can avoid linking specific PMI values ​​to specific beam configurations at the second device 220. The second device 220 can perform this mapping and transmit it to the first device 210, thereby allowing the first device 210 to limit SINR calculations for subsets of PMIs initiated for the gNB. Figure 4 For example, by configuring a subset of PMIs for the first device 210, the first device 210 can perform the estimation of the optimal PMI by estimating PMI#2, PMI#3, PMI#33, PMI#34, PMI#66, and PMI#67, without considering other PMIs. This reduces computation.

[0063] A prerequisite for this method is that the second device 220 configures the first device 210 for full conventional type 1CB (or the disclosed low-resolution CB) DL MIMO to obtain updates for the full channel characteristics. The second device 220 can then replace these conventional procedures by instructing the first device 210 to evaluate only a subset of PMI values ​​within a given time period based on the channel coherence.

[0064] Already referenced Figure 3 and Figure 4Several example embodiments of PMI subset configuration are described. According to example embodiments of this disclosure, another solution for PMI configuration is provided. In this solution, a second device, such as a network device, sends configuration information for multiple codebooks to a first device, such as a terminal device. The codebooks include a set of PMIs. For example, the multiple codebooks may have different resolutions. The second device also sends an indication to the first device for indicating CSI determination based on a second codebook rather than a previously used first codebook among the multiple codebooks. The first device determines at least one CSI quantity for at least one PMI indicated by the second codebook for at least one layer based on the CSI RS from the second device. In this way, the second device can configure the first device to determine the CSI quantity of a subset of PMIs indicated by the second codebook rather than all PMIs. The PMI subset can be identified by the second device as the preferred PMIs most likely to result in the optimal SINR for the DL MIMO layer. The calculations used to derive the optimal PMI from the complete codebook can be reduced, especially in the case of a large number of antenna ports.

[0065] Figure 5 Example signaling flow 500 for CB-based PMI configuration is shown according to some example embodiments of this disclosure. Signaling flow 500 relates to... Figure 2 The first device 210 and the second device 220 in the middle.

[0066] In operation, the second device 220 sends (5010) configuration information of multiple codebooks to the first device 210. The codebooks include a set of PMIs. Accordingly, the first device 210 receives (5015) this configuration information. For example, the configuration information may be included in Radio Resource Control (RRC) configuration or any other suitable message or signaling.

[0067] The second device 220 sends an instruction (5030) to the first device 210 indicating that the determination of the CSI (also known as the estimation or evaluation of the CSI) is based on a second codebook among multiple codebooks rather than a previously used first codebook. Accordingly, the first device 210 receives the instruction (5035). As an example, the instruction may be included in DCI, MAC CE, etc.

[0068] The second device 220 transmits (5040) at least one CSI RS to the first device 210 via a uniform beam at at least one antenna port. The first device 210 receives (5045) the at least one CSI RS.

[0069] The first device 210 determines (5050) at least one CSI quantity of at least one PMI indicated by the second codebook for at least one layer based on at least one CSI RS. The CSI quantity (also referred to as CSI parameter) may include, but is not limited to, RSRP, SRI, RI, CQI, etc. The at least one layer may include each DL MIMO layer.

[0070] The first device 210 may send (5060) to the second device 220 at least one CSI quantity of at least one PMI indicated by a second codebook for at least one layer. Accordingly, the second device 220 receives (5065) from the first device 210 at least one CSI quantity of at least one PMI indicated by the second codebook for at least one layer (such as each DL MIMO layer). The at least one CSI quantity may be included in UCI, CSI reports, etc.

[0071] In some example embodiments, the first resolution of the PMI in the first codebook is lower than the second resolution of the PMI in the second codebook. For example, the first codebook of the PMI may be a full Type 1 codebook for DL ​​MIMO. The second codebook may be a codebook with a higher resolution.

[0072] Figure 6 Example Figure 600 illustrates a gNB beam-to-PMI mapping with multiple CBs according to some example embodiments of the present disclosure. As shown, the multiple PMIs for low-resolution beams (such as beam 610) can be indicated by a first codebook. A second codebook indicates the multiple PMIs for high-resolution beams (such as beam 620).

[0073] Return to reference Figure 6 In some example embodiments, the first device 210 may use SVD, a full exhaustive scheme, a scheme specific to the first device 210, etc., to select a PMI for at least one layer from the PMIs of the first codebook. The first device 210 may send at least one CSI value of the selected PMI for the at least one layer to the second device 220. Accordingly, the second device 220 receives at least one CSI value of the selected PMI.

[0074] The second device 220 can select a second codebook from multiple codebooks based at least on at least one CSI value of the PMI selected by the first device 210. For example, the second device 220 can determine at least one refined beam and at least one corresponding PMI based on MIMO type, cell load, the need for subband precoding, at least one CSI value of the PMI selected by the first device 210, etc. The second device 220 can select the second codebook based on at least one corresponding PMI. Then, the second device 220 can send (5030) an indication of the second codebook to the first device 210. At least one adjacent refined beam is associated with a subset of the higher resolution beams of the second codebook, rather than with the adjacent beams indicated by the first codebook.

[0075] For example, the second device 220 may be configured with two codebooks or two sets of codebooks. The low-resolution codebook (e.g., with a smaller number of PMI values) may be used for a complete evaluation (exhaustive search) at the first device 210, and the high-resolution codebook may be used for a subset of PMIs selected by the gNB.

[0076] In some example embodiments, the first device 210 may send capability information of the first device 210 to the second device 220, the capability information indicating support for CSI evaluation for multiple codebooks. The second device 220 may receive the capability information of the first device 210. In response to the first device 210 supporting CSI evaluation for multiple codebooks, the second device 220 may configure multiple codebooks for the first device 210 and indicate a second codebook to the first device 210 when necessary.

[0077] Already referenced Figures 3 to 6 Several example embodiments of CSI estimation based on a subset of PMI are described. Reference will be made to... Figure 7 Other example embodiments describing PMI subset configurations, Figure 7 Another example signaling flow 700 for PMI configuration is shown according to some example embodiments of this disclosure. Signaling flow 700 relates to... Figure 2 The first device 210 (such as UE) and the second device 220 (such as gNB) in the process.

[0078] It should be understood, as referenced above Figure 3 and Figure 5 Some of the features and operations described in relation to the first device 210 and the second device 220 also apply to Figure 7 The signaling flow in the middle has a similar effect. For the sake of simplicity, the details will not be repeated.

[0079] In step #1, it is assumed that the first device 210 is connected to the second device 220 by RRC. At step #2, the first device 210 may send its capability report, which may include indications of support for the evaluation of a preferred subset of PMIs for the second device 220.

[0080] In step #3, the second device 220 may initiate codebook-based DL MIMO. In step #4, the second device 220 transmits conventional CSI-RS on all configured APs using a uniform beam configuration. The second device 220 requires this step to estimate the initial angular orientation of the first device 210. Thus, this conventional step may still need to be initiated from time to time.

[0081] In step #5, the first device 210 can derive the preferred PMI for each MIMO layer by using SVD, a full exhaustive scheme, or a UE vendor-specific scheme. In step #6, the first device 210 can derive the CSI parameters (RSRP, CRI, RI, and CQI) of the selected PMI for each MIMO layer. In step #7, the first device 210 can transmit the CSI value via UCI for each MIMO layer.

[0082] In some example embodiments, the second device 220 may initiate SRS-based DL MIMO to verify the PMI selection of the first device 210 or estimate the angular orientation of the first device 210. Thus, steps #4 to #7 can be replaced by conventional SRS-based DL MIMO signaling.

[0083] In step #8, the second device 220 initiates a PMI update and determines the adjacent beam configuration and the corresponding PMI for the currently used PMI value. In step #9, the second device 220 notifies the first device 210 of the preferred subset of PMIs for the gNB beams adjacent to the currently configured gNB beams for each MIMO layer. This can be done via DCI or MAC CE, etc.

[0084] In step #10, the second device 220 transmits CSI-RS on all configured APs using a unified beam configuration. In step #11, the first device 210 derives CSI parameters (RSRP, CRI, RI, and CQI) for each subset of PMIs for each MIMO layer. In step #12, the first device 210 transmits CSI values ​​via UCI for each MIMO layer.

[0085] Using these embodiments, the computation required to derive the optimal PMI from the full codebook can be reduced, even with a large number of antenna ports. This avoids the very computationally intensive process of deriving the optimal PMI from the full codebook in the case of a large number of antenna ports.

[0086] It should be understood that the above provides some example specifications, signaling flows, and embodiments, and the detailed description may be changed. It should be understood that these signaling flows 300, 500, and / or 700 can be used individually or in any suitable combination. Some example embodiments, operations, or features described with reference to one of these signaling flows 300, 500, and / or 700 can be applied to another signaling flow within these signaling flows. A portion of one of these signaling flows 300, 500, and / or 700 can be applied in combination with a portion of another signaling flow. It should be understood that these signaling flows 300, 500, and / or 700 can involve any other suitable operations or signaling not shown. Utilizing these signaling flows and similar signaling flows can enhance PMI estimation.

[0087] Figure 8 A flowchart of an example method 800 implemented at a first device according to some example embodiments of the present disclosure is shown. For the purposes of discussion, [the following will be discussed]. Figure 2 The method 800 is described by the angle of the first device 210 in the first device.

[0088] In block 810, the first device 210 receives configuration information reported by the channel state information (CSI) from the second device, which indicates multiple precoding matrix indicators (PMIs).

[0089] At frame 820, the first device 210 receives configuration of a subset of PMIs from the second device, wherein the plurality of PMIs includes at least a subset of PMIs.

[0090] At frame 830, the first device 210 receives at least one CSI reference signal (RS) from the second device, the at least one CSI RS being transmitted via a uniform beam at at least one antenna port.

[0091] At block 840, the first device 210 determines at least one CSI quantity for a subset of PMIs for at least one layer based on the configuration and at least one CSI RS.

[0092] In some example embodiments, method 800 further includes sending at least one CSI quantity to a second device for a subset of PMIs for at least one layer.

[0093] In some example embodiments, method 800 further includes sending capability information of the first device to the second device, the capability information indicating support for CSI assessment of a subset of PMI.

[0094] In some example embodiments, the configuration information includes a first codebook indicating multiple PMIs.

[0095] In some example embodiments, a subset of PMIs includes at least one PMI indicated by a first codebook.

[0096] In some example embodiments, the configuration includes determining the duration of CSI for a subset of PMIs.

[0097] In some example embodiments, the configuration is included in at least one of the following: downlink control information or media access control elements.

[0098] In some example embodiments, method 800 further includes: selecting a PMI for at least one layer using at least one of the following: singular value decomposition, a fully exhaustive scheme, or a scheme specific to the first device; and sending at least one CSI quantity of the selected PMI for at least one layer to a second device, wherein a subset of PMIs is determined based on at least one CSI quantity of the selected PMI.

[0099] In some example embodiments, the first device includes a terminal device, and the second device includes a network device.

[0100] In some example embodiments, a first device capable of performing any of the methods 800 (e.g., Figure 2 The first device 210 may include components for performing the corresponding operation of method 800. The device may be implemented in any suitable form. For example, the device may be implemented in a circuit system or a software module. The first device may be implemented as or included in... Figure 2 In the first device 210.

[0101] Figure 9 A flowchart of an example method 900 implemented at a second device according to some example embodiments of the present disclosure is shown. For the purposes of discussion, [the following will be discussed]. Figure 2 Method 900 is described by the angle of the second device 220 in the middle.

[0102] In box 910, Figure 2 The second device 220 sends configuration information of the Channel State Information (CSI) report to the first device, which indicates multiple Precoding Matrix Indicators (PMIs).

[0103] At position 920, Figure 2 The second device 220 sends the configuration of a subset of PMIs to the first device, wherein the plurality of PMIs includes at least a subset of PMIs.

[0104] At position 930 in the box Figure 2 The second device 220 in the first device sends at least one CSI reference signal (RS) to the first device, the at least one CSI RS being transmitted via a uniform beam at at least one antenna port.

[0105] At position 940 in the box Figure 2The second device 220 receives from the first device at least one CSI quantity for a subset of PMIs for at least one layer.

[0106] In some example embodiments, method 900 further includes: receiving from a first device at least one CSI quantity of a PMI selected by the first device for at least one layer; determining a subset of PMIs based at least on the at least one CSI quantity of the PMIs selected by the first device; and sending a configuration of the subset of PMIs to the first device.

[0107] In some example embodiments, method 900 further includes determining at least one adjacent beam and at least one corresponding PMI based on at least one of the following: multiple-input multiple-output (MIMO) type, cell load, subband precoding requirements, or at least one CSI quantity of the PMI selected by the first device, wherein a subset of the PMIs includes at least one corresponding PMI.

[0108] In some example embodiments, method 900 further includes receiving capability information of the first device from the first device, the capability information indicating support for CSI assessment for a subset of PMI.

[0109] In some example embodiments, the configuration information includes a first codebook indicating multiple PMIs.

[0110] In some example embodiments, a subset of PMIs includes at least one PMI indicated by a first codebook.

[0111] In some example embodiments, the configuration is included in at least one of the following: downlink control information or media access control elements.

[0112] In some example embodiments, the first device includes a terminal device, and the second device includes a network device.

[0113] In some example embodiments, a second means capable of performing any of the methods 900 (e.g., Figure 2 The second device 220 may include components for performing the corresponding operations of method 900. This device can be implemented in any suitable form. For example, it can be implemented in a circuit system or a software module. The second device can be implemented as or included in... Figure 2 In the second device 220.

[0114] Figure 10 A flowchart of an example method 1000 implemented at a first device according to some example embodiments of the present disclosure is shown. For the purposes of discussion, [the following will be discussed]. Figure 2 Method 1000 is described by the angle of the first device 210 in the middle.

[0115] At frame 1010, the first device 210 receives configuration information for multiple codebooks from the second device, the codebooks including a set of precoding matrix indicators (PMIs).

[0116] At block 1020, the first device 210 receives from the second device an indication that the determination of the channel state information (CSI) is based on the second codebook among a plurality of codebooks rather than the first codebook previously used.

[0117] At block 1030, the first device 210 receives at least one CSI reference signal (RS) from the second device, the at least one CSI RS being transmitted via a uniform beam at at least one antenna port.

[0118] At box 1040, the first device 210 determines at least one CSI quantity of at least one PMI indicated by the second codebook for at least one layer based on at least one CSI RS.

[0119] In some example embodiments, method 1000 further includes sending at least one CSI quantity to a second device for a subset of PMIs for at least one layer.

[0120] In some example embodiments, at least one CSI quantity is included in the uplink control information.

[0121] In some example embodiments, method 1000 further includes sending capability information of the first device to a second device, the capability information indicating support for CSI evaluation of multiple codebooks.

[0122] In some example embodiments, the first resolution of the PMI in the first codebook is lower than the second resolution of the PMI in the second codebook.

[0123] In some example embodiments, the first codebook of the PMI includes a full Type 1 codebook for downlink multiple-input multiple-output (MIMO) or downlink MIMO based on a probe reference signal.

[0124] In some example embodiments, the indication is included in at least one of the downlink control information or media access control elements.

[0125] In some example embodiments, method 1000 further includes: selecting a PMI for at least one layer using at least one of the following: singular value decomposition, a complete exhaustive scheme, or a scheme specific to the first device; and sending at least one CSI quantity of the selected PMI for at least one layer to a second device, wherein the second codebook is determined based on at least one CSI quantity of the selected PMI.

[0126] In some example embodiments, the first device includes a terminal device, and the second device includes a network device.

[0127] In some example embodiments, a first device capable of performing any of method 1000 (e.g., Figure 2 The first device 210 may include components for performing the corresponding operation of method 1000. The device may be implemented in any suitable form. For example, the device may be implemented in a circuit system or a software module. The first device may be implemented as or included in... Figure 2 In the first device 210.

[0128] Figure 11 A flowchart of an example method 1100 implemented at a second device according to some example embodiments of the present disclosure is shown. For the purposes of discussion, [the following will be discussed]. Figure 2 Method 1100 is described by the angle of the second device 220 in the middle.

[0129] At frame 1110, the second device 220 sends configuration information for multiple codebooks to the first device, the codebooks including a set of precoding matrix indicators (PMIs).

[0130] At box 1120, the second device 220 sends an indication to the first device that the determination of the channel state information (CSI) is based on the second codebook among multiple codebooks rather than the first codebook previously used.

[0131] At frame 1130, the second device 220 transmits at least one CSI reference signal (RS) to the first device, the at least one CSI RS being transmitted via a uniform beam at at least one antenna port.

[0132] At frame 1140, the second device 220 receives from the first device at least one CSI quantity of at least one PMI indicated by the second codebook for at least one layer.

[0133] In some example embodiments, at least one CSI quantity is included in the uplink control information.

[0134] In some example embodiments, method 1100 further includes receiving capability information from a first device indicating support for CSI evaluation of a plurality of codebooks.

[0135] In some example embodiments, the first resolution of the PMI in the first codebook is lower than the second resolution of the PMI in the second codebook.

[0136] In some example embodiments, the first codebook of the PMI includes a full Type 1 codebook for downlink multiple-input multiple-output (MIMO) or downlink MIMO based on a probe reference signal.

[0137] In some example embodiments, the indication is included in at least one of the downlink control information or media access control elements.

[0138] In some example embodiments, method 1100 further includes: receiving from a first device at least one CSI quantity of a PMI selected by the first device for at least one layer; selecting a second codebook from a plurality of codebooks based at least on the at least one CSI quantity of the PMI selected by the first device; and sending an instruction to the first device for the second codebook.

[0139] In some example embodiments, method 1100 further includes: determining at least one refined beam and at least one corresponding PMI based on at least one of the following: multiple-input multiple-output (MIMO) type, cell load, subband precoding requirements, or at least one CSI quantity of the PMI selected by the first device; and selecting a second codebook based on at least one corresponding PMI.

[0140] In some example embodiments, the first device includes a terminal device, and the second device includes a network device.

[0141] In some example embodiments, a second means capable of performing any of method 1100 (e.g., Figure 2 The second device 220 may include components for performing the corresponding operations of method 1100. This device can be implemented in any suitable form. For example, it can be implemented in a circuit system or a software module. The second device can be implemented as or included in... Figure 2 In the second device 220.

[0142] Figure 12 This is a simplified block diagram of a device 1200 suitable for implementing an example embodiment of the present disclosure. The device 1200 can be provided to implement a communication device, such as... Figure 2 The first device 210 or the second device 220 are shown. As shown, the device 1200 includes one or more processors 1210, one or more memories 1220 coupled to the processors 1210, and one or more communication modules 1240 coupled to the processors 1210.

[0143] Communication module 1240 is used for bidirectional communication. Communication module 1240 has one or more communication interfaces to support communication with one or more other modules or devices. The communication interface can represent any interface required for communication with other network elements. In some example embodiments, communication module 1240 may include at least one antenna.

[0144] As a non-limiting example, processor 1210 can be any type suitable for a local technology network and can include one or more of the following: general-purpose computer, special-purpose computer, microprocessor, digital signal processor (DSP), and processor based on a multi-core processor architecture. Device 1200 can have multiple processors, such as application-specific integrated circuit chips, which are time-dependent on the clock of a synchronous main processor.

[0145] Memory 1220 may include one or more non-volatile memories and one or more volatile memories. Examples of non-volatile memories include, but are not limited to, read-only memory (ROM) 1224, electrically programmable read-only memory (EPROM), flash memory, hard disk, optical disc (CD), digital video disc (DVD), optical disc, laser disc, and other magnetic and / or optical storage. Examples of volatile memories include, but are not limited to, random access memory (RAM) 1222 and other volatile memories that do not retain data during power outages.

[0146] Computer program 1230 includes computer-executable instructions that are executed by an associated processor 1210. The instructions of program 1230 may include instructions for performing operations / actions of some example embodiments of this disclosure. Program 1230 may be stored in memory (e.g., ROM 1224). Processor 1210 can perform any suitable actions and processes by loading program 1230 into RAM 1222.

[0147] The exemplary embodiments of this disclosure can be implemented by program 1230, enabling device 1200 to execute as described in the reference. Figures 3 to 11 Any process discussed in this disclosure. Exemplary embodiments of this disclosure may also be implemented by hardware or by a combination of software and hardware.

[0148] In some example embodiments, program 1230 may be tangibly contained in a computer-readable medium, which may be included in device 1200 (such as memory 1220) or other storage device accessible by device 1200. Device 1200 may load program 1230 from the computer-readable medium into RAM 1222 for execution. In some example embodiments, the computer-readable medium may include any type of non-transitory storage medium, such as ROM, EPROM, flash memory, hard disk, CD, DVD, etc. As used herein, the term "non-transitory" is a limitation on the medium itself (i.e., tangible, not tactile), rather than a limitation on the persistence of data storage (e.g., RAM versus ROM).

[0149] Figure 13An example of a computer-readable medium 1300 is shown, which may be in the form of a CD, DVD, or other optical storage disc. A program 1230 is stored on the computer-readable medium 1300.

[0150] Clause 1. A first means for communication, comprising: at least one processor; and at least one memory storing instructions, the instructions, when executed by the at least one processor, causing the first means to: receive configuration information of a plurality of codebooks from the second means, the codebooks including a set of precoded matrix indicators (PMIs); receive from the second means an indication that the determination of channel state information (CSI) is based on a second codebook among the plurality of codebooks rather than a previously used first codebook; receive from the second means at least one CSI reference signal (RS), the at least one CSI RS being transmitted via a uniform beam at at least one antenna port; and determine, based on the at least one CSI RS, at least one CSI quantity for at least one PMI indicated by the second codebook for at least one layer.

[0151] Clause 2. The first device according to Clause 1, wherein the first device is further caused to: send to the second device the at least one CSI quantity for the subset of PMI for the at least one layer.

[0152] Clause 3. The first device according to Clause 2, wherein at least one CSI quantity is included in the uplink control information.

[0153] Clause 4. The first device according to Clause 1, wherein the first device is further caused to: send capability information of the first device to the second device, the capability information indicating support for CSI evaluation for the plurality of codebooks.

[0154] Clause 5. The first device according to Clause 1, wherein the first resolution of the PMI in the first codebook is lower than the second resolution of the PMI in the second codebook.

[0155] Clause 6. A first device according to any one of Clauses 1 to 5, wherein the first codebook of the PMI includes a complete Type 1 codebook for downlink multiple-input multiple-output MIMO or downlink MIMO based on a probe reference signal.

[0156] Clause 7. A first device according to any one of Clauses 1 to 5, wherein the first device is further caused to: select a PMI for the at least one layer using at least one of the following: singular value decomposition, a complete exhaustive scheme, or a scheme specific to the first device; and send at least one CSI quantity of the selected PMI for the at least one layer to a second device, wherein the second codebook is determined based on the at least one CSI quantity of the selected PMI.

[0157] Clause 8. A second means for communication, comprising: at least one processor; and at least one memory storing instructions, the instructions, when executed by the at least one processor, causing the second means to: transmit configuration information of a plurality of codebooks to a first means, the codebooks including a set of precoded matrix indicators (PMIs); transmit to the first means an indication that the determination of channel state information (CSI) is based on a second codebook among the plurality of codebooks rather than a previously used first codebook; transmit to the first means at least one CSI reference signal (RS), the at least one CSI RS being transmitted via a uniform beam at at least one antenna port; and receive from the first means at least one CSI quantity for at least one PMI indicated by the second codebook for at least one layer.

[0158] Clause 9. The second device according to Clause 8, wherein the second device is further caused to: receive capability information of the first device from the first device, the capability information indicating support for CSI evaluation for the plurality of codebooks.

[0159] Clause 10. The second device according to Clause 8 or 9, wherein the first resolution of the PMI in the first codebook is lower than the second resolution of the PMI in the second codebook.

[0160] Clause 11. The second device according to Clause 8 or 9, wherein the first codebook of the PMI includes a full Type 1 codebook for downlink multiple-input multiple-output MIMO or downlink MIMO based on a probe reference signal.

[0161] Clause 12. The second means according to Clause 8 or 9, wherein the second means is further caused to: receive from the first means at least one CSI quantity of the PMI selected by the first means for the at least one layer; select the second codebook from the plurality of codebooks based at least on the at least one CSI quantity of the PMI selected by the first means; and send the instruction on the second codebook to the first means.

[0162] Clause 13. The second means according to Clause 12, wherein the second means is further caused to: determine at least one refined beam and at least one corresponding PMI based on at least one of the following: MIMO type, cell load, requirement for subband precoding, or the at least one CSI amount of the PMI selected by the first means; and select the second codebook based on the at least one corresponding PMI.

[0163] Clause 14. A method for communication, comprising: receiving configuration information of a plurality of codebooks from a second device at a first device, the codebooks including a set of precoded matrix indicators (PMIs); receiving from the second device an indication of channel state information (CSI) determined based on a second codebook among the plurality of codebooks rather than a previously used first codebook; receiving from the second device at least one CSI reference signal (RS), the at least one CSI RS being transmitted via a uniform beam at at least one antenna port; and determining at least one CSI quantity of at least one PMI indicated by the second codebook for at least one layer based on the at least one CSI RS.

[0164] Clause 15. A method for communication, comprising: transmitting configuration information of a plurality of codebooks, the codebooks including a set of precoded matrix indicators (PMIs), from a second device to a first device; transmitting to the first device an indication that the determination of channel state information (CSI) is based on a second codebook among the plurality of codebooks rather than a previously used first codebook; transmitting at least one CSI reference signal (RS) to the first device, the at least one CSI RS being transmitted via a uniform beam at at least one antenna port; and receiving from the first device at least one CSI quantity of at least one PMI indicated by the second codebook for at least one layer.

[0165] Generally, the various embodiments of this disclosure can be implemented in hardware or dedicated circuitry, software, logic, or any combination thereof. Some aspects can be implemented in hardware, while others can be implemented in firmware or software that can be executed by a controller, microprocessor, or other computing device. Although various aspects of the embodiments of this disclosure are illustrated and described as block diagrams, flowcharts, or using some other graphical representation, it should be understood that, as non-limiting examples, the blocks, apparatuses, systems, techniques, or methods described herein can be implemented in hardware, software, firmware, dedicated circuitry or logic, general-purpose hardware or controllers or other computing devices, or some combination thereof.

[0166] Some exemplary embodiments of this disclosure also provide at least one computer program product tangibly stored on a computer-readable medium, such as a non-transitory computer-readable medium. The computer program product includes computer-executable instructions that execute in a device on a target physical or virtual processor, such as those included in a program module, to perform any of the methods described above. Typically, a program module includes routines, programs, libraries, objects, classes, components, data structures, etc., that perform a particular task or implement a particular abstract data type. In various embodiments, the functionality of a program module can be combined or split among program modules as needed. The machine-executable instructions for a program module can execute within a local or distributed device. In a distributed device, the program module can reside in both local and remote storage media.

[0167] Program code used to perform the methods of this disclosure may be written in any combination of one or more programming languages. The program code may be provided to a processor or controller of a general-purpose computer, special-purpose computer, or other programmable data processing apparatus, such that when executed by the processor or controller, the program code causes the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code may be executed entirely on a machine, partially on a machine, as a stand-alone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0168] In the context of this disclosure, computer program code or related data may be carried by any suitable carrier to enable a device, apparatus, or processor to perform the various processes and operations described above. Examples of carriers include signals, computer-readable media, etc.

[0169] Computer-readable media can be computer-readable signal media or computer-readable storage media. Computer-readable media can include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatuses, or devices, or any suitable combination thereof. More specific examples of computer-readable storage media will include electrical connections having one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable optical disc read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0170] Furthermore, although operations are described in a specific order, this should not be construed as requiring that such operations be performed in the specific order shown or sequentially, or requiring that all shown operations be performed to achieve the desired result. In some cases, multitasking and parallel processing may be advantageous. Similarly, although several specific implementation details are included in the above discussion, these should not be construed as limiting the scope of this disclosure, but rather as a description of features that may be specific to particular embodiments. Unless explicitly stated otherwise, certain features described in the context of a single embodiment may also be implemented in combination in a single embodiment. Conversely, unless explicitly stated otherwise, various features described in the context of a single embodiment may also be implemented individually or in any suitable sub-combination in multiple embodiments.

[0171] Although this disclosure has been described in language specific to structural features and / or methodological actions, it should be understood that the disclosure as defined in the appended claims is not necessarily limited to the specific features or actions described above. Rather, the specific features and actions described above are disclosed as exemplary forms for implementing the claims.

Claims

1. A first device for communication, comprising: At least one processor; as well as At least one memory storing instructions that, when executed by the at least one processor, cause the first device to: The second device receives configuration information for multiple codebooks, which include a set of precoding matrix indicator (PMI) sets. The determination of receiving the Indication Channel State Information (CSI) from the second device is based on the indication of the second codebook among the plurality of codebooks, rather than the indication of the previously used first codebook; Receive at least one CSI reference signal RS from the second device, the at least one CSI RS being transmitted via a uniform beam at at least one antenna port; as well as Based on the at least one CSI RS, at least one CSI quantity is determined for at least one PMI indicated by the second codebook for at least one layer.

2. The first device according to claim 1, wherein the first device is further caused to: Send the at least one CSI quantity to the second device for the subset of PMI for the at least one layer.

3. The first apparatus according to claim 2, wherein the at least one CSI quantity is included in the uplink control information.

4. The first device according to claim 1, wherein the first device is further caused to: The capability information of the first device is sent to the second device, the capability information indicating support for CSI evaluation for the plurality of codebooks.

5. The first apparatus according to claim 1, wherein the first resolution of the PMI in the first codebook is lower than the second resolution of the PMI in the second codebook.

6. The first apparatus according to any one of claims 1 to 5, wherein the first codebook of the PMI comprises a complete Type 1 codebook for downlink multiple-input multiple-output MIMO or downlink MIMO based on a probe reference signal.

7. The first device according to any one of claims 1 to 5, wherein the first device is further caused to: The PMI for the at least one layer is selected using at least one of the following: singular value decomposition, a complete exhaustive scheme, or a scheme specific to the first device; and Send at least one CSI value for a selected PMI for the at least one layer to the second device, wherein the second codebook is determined based on the at least one CSI value of the selected PMI.

8. A second means for communication, comprising: At least one processor; as well as At least one memory storing instructions, which, when executed by the at least one processor, cause the second device to: Configuration information for multiple codebooks is sent to the first device. The codebooks include a set of precoding matrix indicator (PMI) sets. The determination of sending the indication channel state information (CSI) to the first device is based on the indication of the second codebook among the plurality of codebooks rather than the previously used first codebook; At least one CSI reference signal RS is transmitted to the first device, the at least one CSI RS being transmitted via a uniform beam at at least one antenna port; as well as Receive from the first device at least one CSI quantity for at least one PMI indicated by the second codebook for at least one layer.

9. The second device according to claim 8, wherein the second device is further caused to: Receive at least one CSI quantity of PMI selected by the first device for the at least one layer from the first device; The second codebook is selected from the plurality of codebooks based at least on the at least one CSI quantity of the PMI selected by the first device; as well as The instruction to the second codebook is sent to the first device.

10. The second device according to claim 9, wherein the second device is further caused to: At least one refined beam and at least one corresponding PMI are determined based on at least one of the following: MIMO type, cell load, subband precoding requirements, or the at least one CSI quantity of the PMI selected by the first device; and The second codebook is selected based on at least one corresponding PMI.

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