Send port information using signals

Abstract

Methods and apparatus for multichannel communication are disclosed. One method provides the following operations: precoding a reference signal port in the spatial and frequency domains based on a probe reference signal received from a communication device by determining spatial and frequency domain component pairs, wherein the frequency domain components are arranged in clusters comprising one or more frequency domain components, and pairing of at least one spatial domain component with at least two clusters of frequency domain components is supported; transmitting the precoded information to other communication devices; and combining the precoded information with a precoded report received in response from the other communication devices. Another method provides the following operations: transmitting a probe reference signal; receiving precoded information; performing a port selection operation based on clustering information of the frequency domain components; and preparing and transmitting a report based on the selection operation.

Description

[0001] This application is a divisional application of the invention patent application with application number 202111235711.3, application date October 22, 2021, priority date October 23, 2020, and invention title "Transmitting Port Information with Signals". Technical Field

[0002] This disclosure relates to methods, apparatus, and computer program products for transmitting port information via signals between communication devices. Background Technology

[0003] A communication session can be established between two or more communication devices, such as user or terminal equipment, base stations / access points, and / or other nodes. For example, a communication session can be provided using a communication network and one or more compatible communication devices. The network-side communication devices provide access points to the system and are equipped with appropriate signal receiving and transmitting means to enable communication, such as allowing other devices to access the communication system. A communication session can include, for example, data communication for carrying communications such as voice, video, email, text messages, multimedia, and / or content data. Non-limiting examples of the services provided include two-way or multi-way calling, data communication, multimedia services, and access to data network systems such as the Internet.

[0004] In mobile or wireless communication systems, at least a portion of a communication session between at least two devices occurs over a wireless or radio link. Examples of wireless systems include Public Land Mobile Networks (PLMNs), satellite-based communication systems, and various wireless local area networks (WLANs). Users can access a wider range of communication systems using appropriate communication equipment or terminals. A user's communication equipment may be referred to as User Equipment (UE) or User Appliance.

[0005] Communication equipment is provided with appropriate signal receiving and transmitting means to enable communication, such as enabling access to a communication network or direct communication with other users. A user's communication equipment can access a carrier provided by a station in a radio access network (e.g., a base station) and transmit and / or receive communication on that carrier. Modern systems are characterized by multipath operation capabilities. Communication equipment can communicate via multiple paths. Multipath communication can be provided by means of an arrangement known as Multiple-Input Multiple-Output (MIMO).

[0006] Communication systems and associated equipment typically operate according to a given standard or specification that defines what the various entities associated with the system are allowed to do and how they should be implemented. The communication protocols and / or parameters to be used for connectivity are also usually defined. An example of a communication system is UTRAN (3G Radio). Other examples are the Long Term Evolution (LTE) of Universal Mobile Telecommunications System (UMTS) radio access technology and so-called fifth-generation (5G) or new radio (NR) networks. 5G is being standardized by the 3rd Generation Partnership Project (3GPP). Successive versions of this standard are called releases (Rel). In 3GPP 5G NR, the standardization work will further enhance MIMO Channel State Information (CSI) feedback by utilizing partial uplink / downlink (UL / DL) reciprocity of certain channel statistics. Summary of the Invention

[0007] According to one aspect, a method for multichannel communication is provided, the method comprising: precoding a reference signal port in the spatial and frequency domains based on a probe reference signal received from a communication device by determining spatial and frequency domain component pairs, wherein the frequency domain components are arranged in clusters comprising one or more frequency domain components, and pairing of at least one spatial domain component with at least two clusters of frequency domain components is supported; transmitting the precoded information to other communication devices; and combining the precoded information with a report in response to the precoded information received from other communication devices.

[0008] According to one aspect, a method for multichannel communication is provided, the method comprising: transmitting a probe reference signal to a communication device; receiving, in response, precoded information from the communication device, the precoded information including information on reference signal ports in a defined spatial and frequency domains by spatial and frequency domain components, wherein the frequency components are arranged in clusters comprising one or more frequency components, and pairing of at least one spatial component with at least two clusters of frequency components is supported; performing a port selection operation based on the clustering information of the frequency components; and preparing and transmitting a report based on the selection operation.

[0009] According to one aspect, an apparatus is provided, comprising at least one processor and at least one memory including computer program code, the at least one memory and the computer program code being configured, together with the at least one processor, to cause the apparatus to at least: perform precoding on a reference signal port in the spatial and frequency domains by determining spatial and frequency component pairs based on a probe reference signal received from a communication device, wherein the frequency components are arranged in clusters comprising one or more frequency components, and pairing of at least one spatial component with at least two clusters of frequency components is supported; transmit the precoded information to other communication devices; and combine the precoded information with a report in response to the precoded information received from other communication devices.

[0010] According to one aspect, an apparatus is provided, comprising at least one processor and at least one memory including computer program code, the at least one memory and the computer program code being configured, together with the at least one processor, to cause the apparatus to at least: transmit a probe reference signal to a communication device; receive precoded information from the communication device, the precoded information including information on reference signal ports in a defined spatial and frequency domains by spatial and frequency domain components, wherein the frequency components are arranged in clusters comprising one or more frequency components, and pairing of at least one spatial component with at least two clusters of frequency components is supported; perform a port selection operation based on the clustering information of the frequency components; and prepare and transmit a report based on the selection operation.

[0011] In more detail, the report received from the selected communication device includes a precoder matrix indication. This combination includes generating a reconstructed precoder for use in the communication.

[0012] A portion of the frequency domain compression operation can be performed before transmitting precoded information, with the receiving communication device configured to perform another portion of the frequency domain compression operation. More of the frequency domain compression operation can be performed at the device performing the precoding operation compared to the receiving device. A smaller portion of the combined frequency domain compression operation can be performed at the device receiving the precoded information.

[0013] Transmitting precoded information may include transmitting a channel state information reference signal based on precoding, for use when selecting a channel state information reference signal port or a precoded pair associated with those ports. The selection of a channel state information reference signal port or a precoded pair associated with that port can then be performed. In response, a precoding matrix indicator report can be sent based on the channel state information reference signal port or precoded pair selected by the communication device receiving the channel state information reference signal.

[0014] The communication device can be configured to participate in calculating frequency domain components based on a restricted subset of the discrete Fourier transform codebook for spatial and frequency domain component pairs, and, in response to a channel state information reporting request, report information on selecting non-zero coefficients from a sequence of frequency domain components calculated from all spatial frequency components measured for a reference signal port, an indicator indicating the spatial frequency pairs, and the frequency domain components corresponding to the reported non-zero coefficients.

[0015] A restricted subset of the Discrete Fourier Transform (DFT) components can be provided. This subset may include a window of continuous components or a set of discontinuous components that include at least the DFT codebook with component 0. The restricted subsets of the DFT components may be the same or different in size or number of components for different groups of spatial frequency pairs.

[0016] The partial reciprocity of cluster delays in channels to and from communication devices can be assumed as the basis for operation.

[0017] The size of the cluster can be determined at least in part based on the estimated cluster latency uncertainty.

[0018] Precoder weights can be calculated. The calculated precoder weights can be combined with precoder matrix indicator information received from the selected communication device to reconstruct the precode.

[0019] Components for implementing the operations and functions disclosed herein may also be provided.

[0020] Computer software products that implement at least a portion of the functions described herein may also be provided. According to one aspect, the computer program includes instructions for performing at least one of the methods described herein. Attached Figure Description

[0021] The following examples and figures will now be used to describe some aspects in more detail, by way of example only:

[0022] Figure 1 Examples of systems in which the present invention can be practiced are illustrated;

[0023] Figure 2 An example of a control device is shown.

[0024] Figure 3 This is a signaling flowchart between two communication devices;

[0025] Figure 4 and Figure 5 It is a flowchart based on some examples;

[0026] Figure 6The illustration shows an example of SD and FD components determined for two SD beams based on the received SRS;

[0027] Figure 7 The pairing of SD and FD components and examples of port selection based on the pairing are shown; and

[0028] Figure 8 , Figure 9 and Figure 10 Another example is shown. Detailed Implementation

[0029] The following description provides exemplary descriptions of some possibilities for practicing the invention. Although the terms "a," "an," or "some" examples or embodiments may be referenced in multiple places in this specification, this does not necessarily mean that every reference refers to the same example(s) or that a particular feature applies only to a single example or embodiment. Individual features of different examples and embodiments may also be combined to provide other embodiments.

[0030] Wireless communication systems provide wireless communication to devices connected to them. Typically, access points such as base stations are provided to enable communication. In the following sections, the 3GPP 5G radio access architecture with MIMO capability will be used as an example of an access architecture to describe different scenarios. However, embodiments are not necessarily limited to this architecture. Some examples of options for suitable systems are Universal Mobile Telecommunications System (UMTS) Radio Access Network (UTRAN or E-UTRAN), Long Term Evolution (LTE), LTE-A (Advanced LTE), Wireless Local Area Network (WLAN or Wi-Fi), and Global Microwave Access Interoperability (WiMAX). Personal Communication Services (PCS) Wideband Code Division Multiple Access (WCDMA), systems using Ultra Wideband (UWB) technology, sensor networks, mobile ac-hoc networks (MANET), cellular Internet of Things (IoT) RAN and Internet Protocol Multimedia Subsystem (IMS), or any combination thereof and further developments.

[0031] Figure 1 A wireless system 1 including a radio access system 2 is shown. The radio access system may include one or more access points or base stations 12. The base stations may provide one or more cells. The access points may include any node capable of transmitting / receiving radio signals (e.g., TRP, 3GPP 5G base stations such as gNB, eNB, user equipment such as UE, etc.).

[0032] Communication device 10 is located within the service area of ​​radio access system 2, and device 10 can therefore listen to access point 12. Communication 11 from device 10 to access point 12 is generally referred to as uplink (UL). Communication 13 from access point 12 to device 10 is generally referred to as downlink (DL). In this example, the downlink is schematically shown as including up to four beams per polarization in the spatial domain (SD).

[0033] Note that the broader communication system is shown only as Cloud 1 and may include multiple elements not shown for clarity. For example, a 5G-based system may consist of a terminal or user equipment (UE), a 5G radio access network (5GRAN) or a next-generation radio access network (NG-RAN), a 5G core network (5GC), one or more application functions (AF), and one or more data networks (DN). The 5G-RAN may include one or more gNodeB (GNB) or one or more gNodeB (GNB) distributed unit functions connected to one or more gNodeB (GNB) centralized unit functions. The 5GC may also include entities such as Network Slice Selection Function (NSSF); Network Exposure Function; Network Repository Function (NRF); Policy Control Function (PCF); Unified Data Management (UDM); Application Function (AF); Authentication Server Function (AUSF); Access and Mobility Management Function (AMF); and Session Management Function (SMF).

[0034] Device 10 can be any suitable communication device suitable for wireless communication. The wireless communication device can be provided by any device capable of transmitting and receiving radio signals. Non-limiting examples include mobile stations (MS) (e.g., mobile devices such as mobile phones or so-called "smartphones"), computers equipped with wireless interface cards or other wireless interface facilities (e.g., USB dongles), personal data assistants (PDAs) or tablet computers equipped with wireless communication capabilities, machine-type communication (MTC) devices, Internet of Things (IoT) type communication devices, or any combination thereof. The device can be provided as part of another device. The device can receive signals via an air or radio interface via suitable means for receiving and can transmit signals via suitable means for transmitting radio signals. Communication can occur via multiple paths. To enable MIMO-type communication, devices 10 and 12 are provided with multiple antenna elements. These are schematically represented by antenna arrays 14 and 15.

[0035] Communication equipment such as access point 12 or user equipment 10 is provided with a data processing means including at least one processor and at least one memory. Figure 2 An example of a data processing device 50 is shown, which includes processors 52, 53 and one or more memories 51. Figure 2The connection between the equipment's components and the interface used to connect the data processing device to other components of the equipment is further illustrated.

[0036] At least one memory may include at least one ROM and / or at least one RAM. The communication device may include other possible components for software and hardware assistance in performing the tasks it is designed to perform, including control of access and communication with access systems and other communication devices, and implementation of the positioning characteristics of the device described herein. At least one processor may be coupled to at least one memory. At least one processor may be configured to execute appropriate software code to implement one or more of the following aspects. The software code may be stored in at least one memory, for example, in at least one ROM.

[0037] The following uses 5G terminology to describe certain aspects of measurement, configuration, and signaling related to multipath or multibeam radio transmission operations. In frequency division duplex (FDD) based systems, full uplink-downlink (UL-DL) channel reciprocity cannot be assumed due to the duplex distance between the uplink (UL) and downlink (DL) channels. However, partial channel reciprocity can be assumed based on certain properties such as angle of departure (AoD), angle of arrival (AoA), and propagation multipath delay. UL-DL partial reciprocity properties can be considered in signaling between communication devices. For example, the gNB can estimate the UL sounding reference signal (SRS) to obtain delay-related information, such as frequency domain (FD) components, which can be the same as the UE selection made via the DL channel state information reference signal (CSI-RS). The gNB can then use the selected FD components to further precode the beamformed CSI-RS resources that already contain spatial domain (SD) beams. To communicate multiple sets of FD components via CSI-RS, more CSI-RS ports need to be configured. This can lead to a significant increase in DL CSI-RS resource consumption proportional to the number of FD components. For example, if each SD beam contains the same number of FD components forming multiple CSI-RS ports, the consumed CSI-RS resources increase exponentially with the increase in precoded FD components. To control the total CSI-RS ports and CSI-RS resource overhead, each SD beam can contain a different number of FD components based on UL sounding reference signal (SRS) measurements. The gNB can also indicate the mapping relationship between CSI-RS ports and SD-FD beam pairs to the UE.

[0038] It has been recognized that MIMO CSI feedback operation can be enhanced by leveraging partial uplink / downlink (UL / DL) reciprocity of certain channel statistics, such as (multiple) angles and (multiple) delays. Enhancements to CSI measurement and reporting have been proposed, which can be based on evaluation and, if necessary, specify port selection codebook enhancements (e.g., based on existing 3GPP Rel.15 / 16 Type II port selection), where information related to (multiple) angles and (multiple) delays is estimated in the gNB based on SRS by leveraging the DL / UL reciprocity of angles and delays, and the remaining DL CSI is reported by the UE. This primarily targets Frequency Range 1 (FR1) Frequency Division Duplex (FDD) to achieve a better trade-off between UE complexity, performance, and reporting overhead. For example, the Type II port selection (PS) codebook was enhanced in 3GPP Rel-16 by introducing frequency domain (FD) compression operations into the 3GPP Rel-15 Type II port selection codebook. For example, this enhanced Type II PS codebook is described in section 5.2.2.2.6 of 3GPP TS 38.214v16.3.0 in September 2020.

[0039] Figure 3 A signaling flowchart based on an example between two communication devices (and more specifically between UE 10 and gNB 12) is shown. The UE sends SRS 30 to the gNB. The gNB can then determine a set of DL precoded vector pairs from the SRS (precoder pair set) by utilizing partial UL-DL reciprocity. The gNB precodes each CSI-RS port using one or more precoder pair sets across the transmission (tx) antenna and frequency element. The precoded CSI-RS is then sent to UE 10 via message 32. The UE then calculates one or more frequency domain components of the configured set for each precoder pair and prepares a PMI report. The PMI includes the selection of precoder pairs and their corresponding combination coefficients. The PMI is signaled to the gNB via message 34. The gNB combines the PMI with its previously prepared precoder pair set to obtain a reconstructed precoder for data and DMRS communication 36.

[0040] Figure 4 The equipment provided in the access network is shown (e.g.) Figure 1A flowchart illustrating an example of operation at access point 12) is provided to facilitate more efficient use of resources for signaling information related to reference signal port information for multiple communications. In this method, a device at 100 receives a probe reference signal from another communication device. The device can then perform precoding of the reference signal port in the spatial and frequency domains at 102 by determining spatial and frequency domain component pairs based on clustering of frequency components. Clustering involves arranging frequency domain components in clusters comprising one or more frequency domain components and such that pairing of at least one spatial domain component with at least two clusters of frequency domain components is supported. The precoded information can be signaled to other communication devices at 104 and later at 106 used to prepare a combination of precoded and port selection reports received from other devices.

[0041] In reciprocity-based port selection operations, other devices can use precoded information sent to them via signaling as part of their CSI report during port selection. This combination provides reconstructed precoding that can be used for data transmission to other devices. More detailed examples of possible ways to use clustered precoding are given below.

[0042] Figure 5 The device shown is receiving pre-encoded information (e.g.) Figure 1 A flowchart illustrating an example of operation at device 10). The device sends a probe reference signal to a communication device at 200, and can then receive precoded information from that communication device. In response to the transmission of the probe reference signal, the device can then receive precoded information from the communication device at 202. This precoded information includes information about reference signal ports in the defined spatial and frequency domains, consisting of spatial domain components and clustered frequency domain components. The frequency domain components are arranged in clusters comprising one or more frequency domain components, and pairing at least one spatial domain component with at least two clusters of frequency domain components is possible. Based on the clustering information of the frequency domain components, a port selection operation is then performed at 204. After selection, a report can be transmitted using a signal at 206 based on the selection operation. Examples of calculations and measurements used for preparing reports and for using reports on other devices are given below.

[0043] The enhanced codebook structure for Select Channel State Information via Signal Transmission Port (PSCSI) is explained in more detail below with examples. In a specific example, the enhancement can be implemented within the context of frequency domain (FD) compression operations. The compression operation can be moved at least partially or largely from the UE to the gNB. This enhancement is based on the assumption of partial reciprocity of cluster delays in the UL and DL channels and the flexibility of using frequency domain components.

[0044] Based on the example, a partitioned FD compression operation is provided, where some FD component calculations are retained at UE10, while some calculations are performed at gNB12, rather than all calculations being performed at either the UE or the gNB. For example, the current port selection codebook specified in 3GPPRel-16 defines that all these calculations are performed at the UE. Depending on the possibility, the gNB performs more of the calculations. The flexible solution described in this paper presents certain advantages because it allows for a reduction in the number of spatial domain (SD-FD) pairs used by the gNB for precoding CSI-RS ports, and thus reference signaling overhead can be reduced. The accuracy of the precoder matrix reconstructed from the PMI reported by the UE and the gNB's own reciprocity-based calculations can also be improved. This is because the UE can be configured to calculate one or more Discrete Fourier Transform (DFT) components within an uncertainty window for each pair of SD-FD components used for precoding CSI-RS ports. The UE can then report the FD components already known to the gNB based on ULSRS, and the gNB can use it to provide more accurate estimates.

[0045] Instead of reporting only one FD component per precoded SD-FD pair, the gNB can configure the UE to compute several FD components within a window corresponding to an identified FD component cluster. The UE can then choose which coefficients to report within the cluster.

[0046] The CSI reporting mechanism can be configured to operate such that the gNB precodes the CSI-RS port in both the spatial and frequency domains using spatial-frequency component pairs, where each spatial component is paired with one or more clusters of frequency components. A cluster may include one or more frequency components.

[0047] In a cluster containing more than one frequency domain component, one frequency domain component can be selected by the gNB to precode the CSI-RS port along with the spatial domain component. This can be the first frequency domain component of the cluster. The UE can be configured to compute, for example, the first three frequency domain components for that CSI-RS port. For illustration, assuming there are N_3 = 13 frequency elements, and the cluster with beam 0 includes DFT components 6, 7, and 8 (a total of 13 components), the gNB can precode the CSI-RS port using the (beam 0, FD component 6) pair and configure the UE to compute FD components 0, 1, and 2. This is equivalent to using a gNB with three CSI-RS ports precoded by the (beam 0, FD component 6) pair, the (beam 0, FD component 7) pair, and the (beam 0, FD component 8) pair, and the UE is configured to compute only FD component 0. Due to the properties of DFT, even outside the cluster, the gNB can use different FD components (e.g., x) for that cluster. In this case, the UE is configured to compute FD components x1, x2, x3 such that (x + [x1, x2, x3]) mod N_3 = [6, 7, 8].

[0048] The size of a cluster can be configured based on an uncertain window. Clusters can be used flexibly. Different clusters can have the same or different numbers of FD components. Each SD beam can be paired with one or more clusters. Different SD beams can have the same or different numbers of clusters. For example, due to the limitations of the FD codebook configured through a window of a given length, the concept of a “cluster” of frequency domain (FD) components can be understood as referring to possible clusters.

[0049] A cluster may include one or more adjacent FD components selected by the gNB, but only the first FD component within the cluster is precoded on the CSI-RS port used for the SD beam.

[0050] The UE can be configured to compute frequency domain components from a restricted subset of the Discrete Fourier Transform (DFT) codebook for each spatial frequency pair. Restrictions on the FD components (Wf) that the UE must compute can be provided. The UE then selects the combination coefficients to report (i.e., FD computation). The UE can, for example, operate in a P×M size... (DL) The bitmap reports the values ​​and positions of these coefficients, where P is the number of SD-FD pairs and M... (DL) This is the size of the subset of FD. If the size of the bitmap is small enough, if M... (DL) If the value is small, then the UE may not need to report Wf.

[0051] This configuration can be provided, for example, through Radio Resource Control (RRC) configuration, semi-static configuration such as Media Access Control Control Element (MAC-CE), or dynamic signaling such as using Downlink Control Information (DCI) fields.

[0052] A restricted subset of DFT components can be provided. This subset includes a window of continuous components or a set of non-continuous components of the DFT codebook, which includes at least component 0. This is the first component of the DFT codebook and is preferred because it provides an "average" measurement. The restricted subset of DFT components can be the same or different in size or in number for different groups of spatial frequency pairs.

[0053] In response to the reception of CSI-RS port information from the gNB, the UE can return a selection of non-zero coefficients, an indicator indicating the spatial frequency pair, and the frequency domain component calculated by the UE corresponding to the reported coefficients, based on a sequence report formed by the frequency domain components calculated by the UE for all spatial frequency components measured in the CSI-RS port.

[0054] refer to Figure 6 and Figure 7 and 3 The GPP Rel-16 eType II codebook explains more detailed examples to further illustrate the principles disclosed in this document. Based on the 3GPP 5G standard, it addresses Layer 1 and all N... t One transmit antenna and N3 precoding matrix indicator (PMI) subbands, N t The ×N3 precoder matrix can be represented as

[0055]

[0056] The two DFT-based compression operations in the spatial domain (SD) and frequency domain (FD) are respectively composed of two bases W1 and W2. express.

[0057] The third operation at UE is from N r Extracting layer representations from each receive antenna. This operation is not specified, but typically involves calculating the strongest v≤N for each PMI subband. r There are eigenvectors such that for t = 0, ..., N³⁻¹, Approximate for the l-th strongest N of subband t t ×1 channel feature vector.

[0058] Enhanced FDD CSI reporting, based on the reciprocity assumptions of cluster latency and angles in FDD operations, allows the gNB to estimate the set of major SD-FD component pairs and use them to precode the CSI-RS port. This allows some, or even most, of the SD and FD compression operations to be moved from the UE to the gNB.

[0059] The gNB can estimate the UL channel and determine P SD-FD vector pairs by measuring the sounding reference signal (SRS). These are used below. It means that, among them It is N t ×1 vector, and It is an N3×1 vector containing precoding weights in the spatial and frequency domains, respectively. The index p = 0, ..., P-1 is associated with the SD-FD pair. The SD component index is i p ∈{0, 1, ..., K-1}, where K is the number of SD beams. FD component indication is f p ∈{0, 1, ..., M (UL) -1}, where M (UL) This indicates the number of FD components. Note that, in general, any two pairs can have the same SD or FD component indices. Let...

[0060]

[0061] It is N t A ×P matrix, whose columns represent weight vectors used for beamforming of CSI-RS ports across the spatial domain, and let

[0062]

[0063] It is an N3×P matrix, and its p-th column... Includes the weights applied to the p-th CSI-RS port across the N3 frequency unit. Know Some vectors in the array can be repeated, but for p = 0, ..., P-1, all vectors in the array must be repeated. They are still different.

[0064] Figure 6 The diagram illustrates K = 2 space beams (beam 0, beam 1) and M. (UL) An example of decomposition of a UL channel with 6 FD components. The SD and FD components can be determined at the gNB based on SRS measurements. The FD components can be extracted from the DFT codebook. The beam representation in the transform domain exposes the main cluster delay measured on that beam.

[0065] The double-headed arrows indicate uncertainties associated with cluster delay estimation in the gNB. These uncertainties can be caused, for example, by mismatches in UL-DL delay reciprocity, impairments in UL channel estimation, and aging effects due to the elapsed time between UL channel estimation from SRS and DL channel estimation from CSI-RS.

[0066] Furthermore, the frequency cells across CSI-RS ports beamformed by certain spatial beams apply DFT vectors as precoding weights corresponding to the cyclic shift of the beam representation in the transform domain. This in Figure 7 The left-hand side is explained, which gives... Figure 6 An example of pairing SD and FD components is shown. More specifically, possible clustered pairings of SD-FD components at the gNB are presented. Clustering is defined by window 20. Pair selection at the UE is then presented in the table on the right. In this case, the UE is configured to compute M for each SD-FD pair. (DL) = 2 FD components (0 and 1). The shaded grid corresponds to the selected SD-FD pair, for which non-zero coefficients can be reported.

[0067] exist Figure 7 In the example, gNB forms clusters of FD components based on window 20. Note the lowest row. y 4 refers to Figure 6 FD component number, Figure 6 The diagram illustrates the FD component estimation based on UL channel measurements by the gNB. For example, the corresponding estimation at the UE may differ and have a strong component for beam 1 in y5.

[0068] The window size can be defined to account for uncertainties. The gNB can pair each spatial beam with the first representative component of the cluster. This example has 3 clusters for beam 0 and 3 clusters for beam 1. The gNB has a total capacity from KM... (UL) = Six out of 12 possible combinations are selected. For precoding of the CSI-RS port, the port is precoded using the first FD component of the cluster, and each cluster can be moved to FD position 0. It should be understood that different numbers of clusters, FD components of each cluster, and beams can be selected.

[0069] For simplicity, we can assume that there are P different SD-FD components and P CSI-RS There is a one-to-one mapping between the ports, making P CSI-RS =P.

[0070] Cross-N bandwidth can be introduced in the bandwidth portion (BWP) configured for CSI reports. PRBP CSI-RS sequences used by each PRB:

[0071]

[0072] use The frequency unit (i.e., the precoding matrix indicator (PMI) subband) corresponding to PRB k is indicated, where This refers to the number of Physical Resource Blocks (PRBs) in a frequency unit. If CDM is used, after code demultiplexing, it is assigned to the unit equipped with N. r The signal Y received by the UE with each receiving antenna in PRB k on the CSI-RS port. k It can be written as N r ×P matrix,

[0073]

[0074] in It is the N of PRBk r ×N t DL channel matrix, N is what the UE sees through the beamformed CSI-RS port. r ×P effective DL channel matrix, and N k It is additive noise.

[0075] CSI-RS measurements on PRBk are given by a matrix.

[0076]

[0077] And the P×N measurements for each SD-FD component pair and receiving antenna on subband t r The matrix can be obtained, for example, by averaging the PRB over the subband.

[0078]

[0079] As mentioned earlier, it can be assumed that the number P of SD-FD component pairs is equal to the number P of CSI-RS ports. CSI-RS This establishes a one-to-one mapping between SD-FD component pairs and ports. However, many-to-one mapping can also be used to reduce the overhead of the DL reference signal. In this case, the above expression is modified to include mapping and demapping operations. An example of a many-to-one mapping operation is... Figure 8 , Figure 9 and Figure 10 The diagram is shown in the image and will be described in more detail later.

[0080] The enhanced port selection codebook structure can be considered based on equation (1), where The codebook is associated with the selection of SD-FD pairs, and With network restrictions to the first M (DL) Each component corresponds to a DFT codebook, where M (DL) It can be very small. A special case is for M. (DL w=1, such that

[0081]

[0082] In this case, the UE only calculates FD component 0, and does not need to perform DFT operations in the frequency domain. The PMI reported by the UE is the same for all subbands because the precoder variations in the frequency domain can be determined by the gNB.

[0083] exist Figure 7 The example considers M greater than 1. (DL) The value of . In this case, a portion of the precoder variation in the frequency can be determined at the UE and gNB. M (DL The case of ) = N3 corresponds to the 3GPP Rel-16 eType II PS codebook, where there are no restrictions on the FD codebook at the UE and no need for FD precoding of the CSI-RS port at the gNB. Figure 7 The example shows the targeting of M (DL) =2 for SD-FD component pairing at gNB and pairing selection at UE. Parameter M (DL) Configuring a value greater than 1 can help reduce the number of SD-FD pairs, and thus reduce the required CSI-RS ports. The accuracy of the reported PMI can also be improved by allowing the UE to operate at lengths of M... (DL) Within the uncertainty window, select (multiple) optimal delays (i.e., FD components) for each FD component identified by gNB to improve performance.

[0084] When parameter M (DL) When the value is greater than 1, the PMI reported by the UE can differ for different subbands. The UE can facilitate operation by determining the frequency domain changes of the precoder. The gNB receives these in the PMI report and can then combine these changes with the frequency-domain precoder changes calculated by the gNB based on the partial reciprocity assumption.

[0085] SD-FD pairs can be generated by the UE from the PM (DL) Choose from 3 possible pairs, for m = 0, ..., M (DL) -1, where the value calculated by the UE for the target The effective FD component is typically a combination of UL and DL FD components. In this case, M (DL) =1, The selected SD-FD pair is by Figure 7 The shaded grids represent, and also correspond to, the reported non-zero coefficients. In this example, the UE selects five primary or strongest pairs.

[0086] To determine the linear combination coefficients for each SD-FD pair and the receiving antenna, the UE can form a P×N3 matrix. For r = 0, ..., N r -1

[0087]

[0088] And the coefficients are calculated by applying (8) to (9). This produces a P×1 vector (or P×M). (DL) Matrix, usually for M (DL) ≥1)

[0089]

[0090] At this stage, the UE can determine the strongest spatial layer from the linear combination of receiving antennas. This can be achieved by applying a single singular value decomposition (SVD) to P×N. r matrix, (or PM) (DL) ×N r (Matrix) and obtain the v strongest left eigenvectors to perform this operation:

[0091]

[0092] In the 3GPP Rel-16 eType II codebook (CB), this layer extraction is typically performed per subband before applying FD compression. However, when FD precoding is applied to the CSI-RS port, the phase relationships between subbands cannot be easily preserved if the eigenvectors are extracted before the summation in (10). The eigenvectors in each subband are determined with phase uncertainty, and for example, they can be adjusted to remove phase jumps between subbands before FD compression. However, when FD precoding is applied at the gNB, these phase adjustments at the UE will alter the phase relationships between subbands and effectively change the effect of the precoder weights applied at the gNB frequency.

[0093] After layer processing, the UE can access the data from layer 1. Floor 2 The subset of the strongest non-zero coefficients is selected from the P coefficients in the equation. The selection of these non-zero linear combination coefficients is used for layer l (or typically in the P×M coefficients). (DL) The coefficient vector P×1 within the matrix can be free, and the corresponding bitmap also indicates the selection of SD-FD pairs.

[0094] Regarding the restrictions on SD-FD pair selection, in 3GPP Rel-15 / 16, port selection is limited to L consecutive port groups, with port groups separated by d≤L ports, and the same ports are used for two polarizations. In contrast, 3GPP Rel-17 allows unrestricted or free selection, with selection extended to P sets of SD-FD pairs, which can be greater than the number of ports P. CSI-RS .

[0095] Given the PMI reconstruction and reciprocity precoder representation, note that if M (DL) =1, then the UE only reports the FD component 0 from the selected SD-FD pair. Let k 0，l k 1，l， …, k L-1，l It is the index of the L selected SD-FD pairs in layer l, where k j，l ∈{0, ..., P-1}. Let It is related to SD-FD to k j，l The corresponding linear combination coefficients, and It is determined by position k j，l The selection vector is formed by all zeros except 1. The P×N3 precoder matrix for layer l reported by the UE in the PMI can be represented as:

[0096]

[0097] Combine the weights calculated by gNB and consider the N of PMI. t ×N3 reciprocal precoders can be represented as

[0098]

[0099] exist Figure 7 In the general case illustrated, M (DL) ≥1, let It is related to SD-FD to k j，l The linear combination coefficients corresponding to the FD component m calculated by the UE. The P×N3 precoder matrix for layer l, as reported by the PMI, can be represented as...

[0100]

[0101] In this case, the weights calculated by gNB are combined and the N of PMI is taken into account. t ×N3 reciprocal precoders can now be represented as

[0102]

[0103] Note that although the above examples have been described with reference to User Equipment (UE) and gNB, similar principles can be applied to any device capable of multi-beam communication.

[0104] Depending on the probability, multiple precoding pairs are mapped to the same CSI-RS port. This is another possibility for reducing the number of ports that need to be reported. Here, by taking advantage of the fact that each frequency element includes multiple PRBs precoded with the same frequency component weights, it is possible to use code division multiplexing (CDM) codes for such pair-to-port multiplexing. P SD-FD precoding pairs and P CSI-RS An example of a many-to-one mapping operation between ≤P CSI-RS ports is shown in Figure 8 The image is shown in the middle. Figure 8 A functional block diagram of the operations performed at gNB is shown. For example... Figure 9 As shown in the functional block diagram of the UE operation, the reverse one-to-many demapping operation occurs at the UE. Figure 10 An example of this many-to-one mapping is shown.

[0105] In the example, the bandwidth portion (BWP) configured for the CSI report is divided into N3 frequency units, and each frequency unit includes... One PRB. For a general frequency cell t, this example shows how a CDM sequence of length 4 can be used to accommodate two SD-FD pairs in a single CSI-RS port. This operation is repeated for all frequency cells with different frequency component weights. Up to An SD-FD pair can be multiplexed on the same port. It should also be noted that... Figure 10 The illustration does not show other possible operations in CSI-RS port sequence generation, such as precoding weights multiplied by the CSI-RS sequence a for port p. p This maps the sequence to a resource element (RE) within the PRB and may multiply it with another CDM sequence associated with the port sequence's mapping to the RE. These operations are typical of CSI-RS transmit sequence generation and are not affected by... Figure 10 The effect of precoding on port mapping is shown in the diagram.

[0106] An apparatus for multichannel communication may include components for precoding reference signal ports in the spatial and frequency domains based on a probe reference signal received from a communication device by determining pairs of spatial and frequency components, wherein the frequency components are arranged in clusters comprising one or more frequency components, and pairing of at least one spatial component with at least two clusters of frequency components is supported; components for transmitting the precoded information to other communication devices; and components for combining the precoded information with a report in response to the precoded information received from other communication devices.

[0107] Another device for multichannel communication may include: components for transmitting a probe reference signal to a communication device; components for receiving precoded information from the communication device in response, the precoded information including information on reference signal ports in the spatial and frequency domains defined by spatial and frequency domain components, wherein the frequency components are arranged in clusters comprising one or more frequency components, and pairing of at least one spatial component with at least two clusters of frequency components is supported; components for performing a port selection operation based on the clustering information of the frequency components; and components for preparing and transmitting a report based on the selection operation.

[0108] It should also be noted that although exemplary embodiments have been described above, various changes and modifications can be made to the disclosed solutions without departing from the scope of the invention. Different features from different embodiments can be combined.

[0109] These embodiments can therefore vary within the scope of the appended claims. Generally, some embodiments can be implemented in hardware or dedicated circuitry, software, logic, or any combination thereof. For example, some aspects may be implemented in hardware, while others may be implemented in firmware or software that can be executed by a controller, microprocessor, or other computing device, although the embodiments are not limited thereto. While various embodiments may be illustrated and described as block diagrams, flowcharts, or using some other graphical representation, it is readily understood that, by way of non-limiting example, the blocks, apparatuses, systems, techniques, or methods described herein may be implemented in hardware, software, firmware, dedicated circuitry or logic, general-purpose hardware or controllers or other computing devices, or some combination thereof.

[0110] This embodiment can be implemented by computer software stored in memory, and can be executed by at least one data processor involving the entity, or by hardware, or by a combination of software and hardware. Furthermore, it should be noted in this regard that any of the above-described processes can represent program steps, or interconnected logic circuits, blocks, and functions, or combinations of program steps and logic circuits, blocks, and functions. The software can be stored on physical media such as memory blocks implemented within memory chips or processors, magnetic media such as hard disks or floppy disks, and optical media such as DVDs and their data variants, CDs.

[0111] The memory can be of any type suitable for the local technical environment and can be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and removable memory. As a non-limiting example, the data processor can be of any type suitable for the local technical environment and can include one or more of general-purpose computers, special-purpose computers, microprocessors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), gate-level circuits, and processors based on multi-core processor architectures.

[0112] Alternatively or additionally, some embodiments may be implemented using a circuit system. This circuit system may be configured to perform one or more of the functions and / or methods previously described. The circuit system may be provided in network entities and / or communication devices and / or servers and / or equipment.

[0113] As used in this application, the term "circuit system" may refer to one or more of the following operations:

[0114] (a) Hardware circuit implementation only (such as implementation only in analog and / or digital circuit systems);

[0115] (b) A combination of hardware circuitry and software, such as:

[0116] (i) A combination of analog and / or (multiple) digital hardware circuits with software / firmware, and

[0117] (ii) Any portion of the hardware processor(s) having software (including (multiple) digital signal processors), the software, and (multiple) memories work together to enable the communication device and / or the device and / or server and / or network entity to perform the various functions previously described; and

[0118] (c) (Multiple) hardware circuits and / or (multiple) processors, such as (multiple) microprocessors or a portion thereof, which require software (e.g., firmware) for operation, but may be absent when not required for operation.

[0119] The definition of circuit system applies to all uses of the term included in any claim of this application. As another example, as used herein, the term circuit system also encompasses implementations of hardware circuitry or processors (or processors in general) or a portion thereof and their accompanying software and / or firmware. The term circuit system also encompasses, for example, integrated devices.

[0120] Note that while embodiments have been described with respect to certain architectures, similar principles can be applied to other systems. Therefore, although the foregoing references to certain exemplary architectures of wireless networks, technology standards, and protocols have described by way of example, the features described herein can be applied to any other suitable form of system, architecture, and device besides those detailed in the examples described above. It should also be noted that different combinations of different embodiments are possible. Furthermore, it should be noted herein that while exemplary embodiments have been described above, various changes and modifications can be made to the disclosed solutions without departing from the spirit and scope of the invention.

Claims

1. An apparatus for communication, comprising at least one processor and at least one memory including computer program code, said at least one memory and said computer program code being configured together with said at least one processor to cause the apparatus to at least: Receive reference signal port information from the base station; The receiving instruction is configured to calculate the number of frequency domain components for the received reference signal port by the device, the number of frequency domain components being within a window associated with the reference signal port; Based on the received reference signal port information, a port selection operation is performed on the reference signal port; For each selected reference signal port, the number of frequency domain components is calculated from a restricted subset of the discrete Fourier transform codebook corresponding to the window; as well as The report is prepared and sent to the base station based on the port selection operation and the calculation.

2. The apparatus of claim 1, wherein the report includes a precoder matrix indication for generating reconstructed precoding by the base station.

3. The apparatus of claim 1, wherein the port selection operation includes selecting at least some of the reference signal ports based on received reference signal port information.

4. The apparatus of claim 1, wherein the apparatus is further configured to signal in the report information selecting non-zero coefficients from a sequence formed by the frequency domain components calculated for each selected reference signal port.

5. The apparatus of claim 4, wherein the information transmitted by signal further indicates the reference signal port corresponding to the reported non-zero coefficient.

6. The apparatus of claim 4, wherein the information further indicates the frequency domain component corresponding to the reported non-zero coefficient.

7. The apparatus of claim 4, wherein the information is transmitted by signaling in response to a channel state information report request.

8. The apparatus of claim 1, wherein the apparatus is further configured to receive a restricted subset of the discrete Fourier transform codebook, wherein the subset comprises a window of continuous components of the discrete Fourier transform codebook, including at least component 0, or a set of discontinuous components.

9. The apparatus of claim 1, wherein the apparatus is further configured to perform a frequency domain compression operation after receiving the reference signal port information from the base station, wherein another frequency domain compression operation has been applied by the base station to the received reference signal port information.

10. The apparatus of claim 1, wherein the received reference signal has been pre-coded by the base station in the spatial and frequency domains, wherein: Based on the probe reference signal transmitted by the device to the base station and the assumption of partial channel reciprocity, the frequency domain components are arranged into clusters, each cluster including frequency domain components within a window of a given length, and The precoding of the reference signal port includes pairing a spatial domain component with a frequency domain component of the cluster.

11. An apparatus for communication, comprising at least one processor and at least one memory including computer program code, said at least one memory and the computer program code being configured, together with said at least one processor, to cause the apparatus to at least: Send reference signal port information to user equipment; Send to the user equipment a configuration indicating the number of frequency domain components to be calculated by the user equipment for a reference signal port, the number of frequency domain components being within a window associated with the reference signal port and calculated from a restricted subset of the discrete Fourier transform codebook corresponding to the window; A report is received from the user equipment, the report being based on the port selection operation and the calculations performed by the user equipment.

12. A method performed by a user equipment, the method comprising: Receive reference signal port information from the base station; The configuration of the number of frequency domain components to be calculated by the user equipment for the received reference signal port, the number of frequency domain components being within a window associated with the reference signal port; Based on the received reference signal port information, a port selection operation is performed on the reference signal port; For each selected reference signal port, the number of frequency domain components is calculated from a restricted subset of the discrete Fourier transform codebook corresponding to the window; as well as The report is prepared and sent to the base station based on the port selection operation and the calculation.

13. The method of claim 12, wherein the report includes a precoder matrix indication for generating reconstructed precoding by the base station.

14. The method of claim 12, further comprising: The report transmits information by signaling the selection of non-zero coefficients from a sequence formed by the frequency domain components calculated for each selected reference signal port.

15. The method of claim 14, wherein the information transmitted by signal further indicates the reference signal port corresponding to the reported non-zero coefficient.

16. The method of claim 14, wherein the information further indicates the frequency domain component corresponding to the reported non-zero coefficient.

17. The method of claim 14, wherein the information is transmitted by signaling in response to a channel state information report request.

18. The method of claim 12, further comprising: Receive a restricted subset of the Discrete Fourier Transform codebook, wherein the subset comprises a window of continuous components of the Discrete Fourier Transform codebook, including at least component 0, or a set of discontinuous components.

19. The method of claim 12, further comprising: After receiving the reference signal port information from the base station, a frequency domain compression operation is performed, wherein another frequency domain compression operation has already been applied by the base station to the received reference signal port information.

20. The method of claim 12, wherein the received reference signal has been pre-coded by the base station in the spatial and frequency domains, wherein: Based on the probe reference signal transmitted by the user equipment to the base station and the assumption of partial channel reciprocity, the frequency domain components are arranged into clusters, each cluster including frequency domain components within a window of a given length, and The precoding of the reference signal port includes pairing a spatial domain component with a frequency domain component of the cluster.

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