Apparatus and method for generating channel state information reference signal in wireless communication system

Abstract

The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. The present invention relates generally to wireless communications, and in particular, to an apparatus and method for generating a CSI-RS. The method provided herein includes, in a base station of a wireless communication system: defining, for a preset number N of digital ports used in the base station, a CSI-RS pattern composed of resource elements, wherein each resource element is defined by a subcarrier in a frequency domain and by an OFDM symbol in a time domain. p ​

Description

Technical Field

[0001] The present invention relates generally to wireless communication, and more specifically to apparatus and methods for generating channel state information reference signals (CSI-RS). Background Technology

[0002] 5G mobile communication technology defines a wide frequency band, enabling high transmission rates and new services. It can be implemented not only in "below 6 GHz" bands such as 3.5 GHz, but also in "above 6 GHz" bands, including 28 GHz and 39 GHz, known as mmWave. Furthermore, 6G mobile communication technology (referred to as "super 5G systems") is being considered in terahertz bands (e.g., the 95 GHz to 3 THz band) to achieve transmission rates fifty times faster than 5G and ultra-low latency one-tenth that of 5G.

[0003] At the outset of 5G mobile communication technology development, standardization was underway regarding beamforming and massive MIMO to support services and meet performance requirements associated with enhanced mobile broadband (eMBB), ultra-reliable low-latency communication (URLLC), and massive machine-type communication (mMTC). This standardization aimed to mitigate radio wave path loss in millimeter waves and increase radio wave transmission distance; support parameter sets for dynamic operation (e.g., operating multiple subcarrier spacings) to efficiently utilize millimeter wave resources and time slot formats; initial access technologies to support multi-beam transmission and broadband; the definition and operation of bandwidth portions (BWP); new channel decoding methods (such as low-density parity-check (LDPC) codes for large data transmissions and polar codes for highly reliable transmission of control information); L2 preprocessing; and network slicing for providing dedicated networks for specific services.

[0004] Currently, given the services supported by 5G mobile communication technology, discussions are underway regarding improvements and performance enhancements to the initial 5G mobile communication technology. Physical layer standardization for technologies such as Vehicle-to-Everything (V2X) is also in place, designed to assist autonomous vehicle driving decisions based on information about the vehicle's location and status transmitted by the vehicle, and to enhance user convenience. This includes NR-U (New Radio Unlicensed) and NR UE Energy Saving (NTN), which are UE-satellite direct communication technologies used to provide coverage and positioning in areas where communication with terrestrial networks is unavailable.

[0005] Furthermore, standardization is ongoing for technologies within the air interface architecture / protocol, such as the Industrial Internet of Things (IIoT) for supporting new services through interoperability and convergence with other industries, Integrated Access and Backhaul (IAB) for providing nodes for network service area extension by supporting wireless backhaul and access links in an integrated manner, mobility enhancements including conditional handover and Dual Active Protocol Stack (DAPS) handover, and two-step random access (two-step RACH for NR) for simplifying the random access process. Standardization is also underway for 5G baseline architectures (e.g., service-based architectures or service-based interfaces) for combining Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, as well as system architectures / services for Mobile Edge Computing (MEC) based on UE location reception services.

[0006] With the commercialization of 5G mobile communication systems, the already exponentially growing number of connected devices will be connected to the communication network, thus necessitating enhanced functionality and performance of 5G mobile communication systems as well as integrated operation of connected devices. To this end, new research related to extended reality (XR) has been arranged to effectively support augmented reality (AR), virtual reality (VR), mixed reality (MR), etc., by leveraging artificial intelligence (AI) and machine learning (ML), AI service support, metaspace service support, and drone communication to improve 5G performance and reduce complexity.

[0007] Furthermore, this development of 5G mobile communication systems will not only serve as the foundation for developing new waveforms for providing terahertz band coverage in 6G mobile communication technologies, such as multi-antenna transmission technologies like full-dimensional MIMO (FD-MIMO), array antennas, and massive MIMO; metamaterial-based lenses and antennas for improving terahertz band signal coverage; high-dimensional spatial multiplexing technologies using orbital angular momentum (OAM); and reconfigurable smart surfaces (RIS); it will also serve as the foundation for developing full-duplex technologies to improve the frequency efficiency of 6G mobile communication technologies and enhance system networks; AI-based communication technologies to achieve system optimization by leveraging satellites and AI from the design phase and internalizing end-to-end AI support functions; and next-generation distributed computing technologies to achieve services with complexity levels exceeding the operational capabilities of UEs by utilizing ultra-high-performance communication and computing resources. Summary of the Invention

[0008] [Technical Issues]

[0009] The purpose of this invention is to provide a configuration for multiplexing CSI-RS, which supports the required number of base station digital ports (up to 256) while avoiding the defects of the prior art.

[0010] In the context of this objective, according to a first aspect of the invention, a method for generating a Channel State Information Reference Signal (CSI-RS) is provided.

[0011] [Problem Solving]

[0012] According to an aspect of this disclosure, a method for generating Channel State Information Reference Signals (CSI-RS) performed by a base station (BS) in a wireless communication system, the method comprising: for a preset number of base stations... The digital port used defines a CSI-RS pattern consisting of resource elements (REs), where each resource element is defined by a subcarrier in the frequency domain and by orthogonal frequency division multiplexing (OFDM) symbols in the time domain. This definition includes, for the CSI-RS pattern: setting the frequency domain... Groups of adjacent physical resource blocks (PRBs) and in the time domain A group of adjacent time slots (TTIs), of which and All are natural numbers, and and At least one of them is greater than 1; set the quantity The code division multiplexing (CDM) group, in which the number is set. The CDM group includes the number of settings in the frequency domain. CDM groups and the number set in the time domain CDM group, ,in and All are natural numbers; define a CDM group, where defining a CDM group includes setting the parameters for the CDM group. The frequency magnitude of each subcarrier is equal to and equal to The time size of each OFDM symbol is equal, making ,in and The settings are intended for reuse within a CDM group. The orthogonal covering code (OCC) of CSI-RS, where the code sequence length of the OCC is . and settings The time-frequency arrangement of each CDM group includes setting the frequency domain. CDM groups in The arrangement of each PRB within a group and in the time domain CDM groups in The arrangement within a time slot group, where the CSI-RS pattern is repeated on the PRB group.

[0013] According to another aspect of this disclosure, a base station (BS) is provided for generating channel state information reference signals (CSI-RS) in a wireless communication system. The base station includes: a transceiver; and at least one processor, the at least one processor being configured to target a preset number of... The digital port used defines a CSI-RS pattern consisting of resource elements (REs), where each resource element is defined by a subcarrier in the frequency domain and by orthogonal frequency division multiplexing (OFDM) symbols in the time domain, wherein at least one processor is further configured to: set the frequency domain... Groups of adjacent physical resource blocks (PRBs) and in the time domain A group of adjacent time slots (TTIs), of which and All are natural numbers, among which and If at least one of them is greater than 1, set the quantity. The code division multiplexing (CDM) group, in which the number is set. The CDM group includes the number of settings in the frequency domain. CDM groups and the number of settings in the time domain CDM group, ,in and All are natural numbers. Define a CDM group, where defining a CDM group includes setting the value equal to the specified value for that CDM group. The frequency magnitude of each subcarrier and equal to The time size of each OFDM symbol, so that ,and and The settings are intended for use in reusing CDM groups. Orthogonal Cover Codes (OCCs) of CSI-RS, where the length of the OCC code sequence is . ,set up The time-frequency arrangement of each CDM group, wherein setting the time-frequency arrangement includes setting the frequency domain CDM groups in The arrangement of each PRB within a group and in the time domain CDM groups in The arrangement within a time slot group, where the CSI-RS pattern is repeated on the PRB group.

[0014] The technical results achievable by this invention are as follows. The CSI-RS configuration proposed in this paper provides support for the number of digital ports required to meet the design requirements of next-generation communication systems, while providing the ability to systematically form CDM groups and arrange them in time and frequency on PRB / time slot groups. It offers greater flexibility in allocating time and frequency resources to each CDM group and has the ability to nest and scale CSI-RS ports in a manner transparent to base stations and user equipment.

[0015] [Advantages and Benefits of This Disclosure]

[0016] According to embodiments of this disclosure, a method and apparatus are provided for efficiently providing configurations for multiplexing CSI-RS, configuring to support the required number of base station digital ports (up to 256), while avoiding the drawbacks of the prior art.

[0017] According to embodiments of this disclosure, a method and apparatus for efficiently generating channel state information reference signals (CSI-RS) are provided. Attached Figure Description

[0018] Figure 1 This is an illustrative example of a two-dimensional antenna subarray for a base station;

[0019] Figure 2a This is another illustrative example of a two-dimensional antenna subarray for a base station;

[0020] Figure 2b It is aimed at Figure 2a A diagram illustrating the CSI-RS pattern of the subarray according to 5G NR;

[0021] Figure 3a This is an illustration based on another CSI-RS pattern of 5G NR;

[0022] Figure 3b This is a diagram based on the CDM type of 5G NR;

[0023] Figure 4 This is a schematic diagram of a wireless communication system in which embodiments of the present invention can be implemented;

[0024] Figure 5a This is an exemplary CSI-RS pattern obtained by extending it to a PRB / time slot group according to the present invention;

[0025] Figure 5b This is an exemplary CSI-RS pattern obtained by extending it to a PRB / time slot group according to the present invention;

[0026] Figure 5c This is an exemplary CSI-RS pattern obtained by extending it to a PRB / time slot group according to the present invention;

[0027] Figure 6a This is an illustration of a system method for constructing a CDM group of CSI-RS patterns according to the present invention;

[0028] Figure 6b This is an illustration of a system method for constructing a CDM group of CSI-RS patterns according to the present invention;

[0029] Figure 6c This is an illustration of a system method for constructing a CDM group of CSI-RS patterns according to the present invention;

[0030] Figure 7a This is a diagram illustrating a possible method that enables user equipment to estimate the required number of CSI-RS;

[0031] Figure 7b This is a diagram illustrating a possible method that enables user equipment to estimate the required number of CSI-RS;

[0032] Figure 8 is a diagram illustrating the hierarchical division of a base station antenna array according to an embodiment of the present invention;

[0033] Figure 9a An embodiment of the virtual partitioning of the antenna array of the base station at the first level according to Figure 8 is shown in more detail;

[0034] Figure 9b yes Figure 9a A diagram illustrating a virtualized nested CSI-RS pattern;

[0035] Figure 10a This is a possible option for indexing CDM groups in a CSI-RS pattern according to an embodiment of the present invention;

[0036] Figure 10b This is a possible option for indexing CDM groups of CSI-RS patterns according to embodiments of the present invention;

[0037] Figure 10c This is a possible option for indexing CDM groups of CSI-RS patterns according to embodiments of the present invention;

[0038] Figure 10d This is a possible option for indexing CDM groups of CSI-RS patterns according to embodiments of the present invention;

[0039] Figure 11 This is a flowchart of the method for generating CSI-RS according to the present invention;

[0040] Figure 12 This is a flowchart of a method for generating CSI-RS according to an embodiment of the present invention. Detailed Implementation

[0041] Today, more and more fifth-generation (5G) new radio (NR) networks are being actively deployed, and their advantages and capabilities are already widely known.

[0042] In 5G NR systems, base stations (BS) use large antenna arrays consisting of multiple transceiver antenna elements (AEs) to efficiently utilize MIMO (Multiple-Input Multiple-Output) technology, which generates multiple spatial MIMO layers to transmit data simultaneously (e.g., Physical Downlink Shared Data Channel (PDSCH)).

[0043] Generally, digital signals are transmitted through one or more digital ports, which are connected to the base station's antenna elements via a radio frequency (RF) unit. The RF unit's function is to convert digital signals forward and backward into analog signals. Specifically, for the 3.5 GHz frequency range, up to 64 digital antenna ports can be used, enabling the use of various precoding schemes in the base station. For example, spatial multiplexing (SM) technology allows the reuse of the same time-frequency resources to transmit multiple signals (MIMO layer) to one or more user equipments (UEs), while adaptive beamforming technology allows the transmitted signal power to be dynamically concentrated in one or more predetermined directions. Advanced modulation techniques, such as orthogonal frequency division multiplexing (OFDM), provide efficient broadband signal transmission.

[0044] The following section will provide a more detailed description of the 5G NR-related aspects discussed above to help understand the technical background of this invention.

[0045] Figure 1 An example of a portion of a two-dimensional antenna array for a base station is shown, where antenna elements (schematically represented by Х in the figure) are virtualized in the horizontal direction. Each antenna port is virtualized in the vertical direction. There are one antenna port. As can be seen from the figure, in this case, a subset of three adjacent antenna elements corresponds to each antenna port. The assumption that each port transmits with two different orthogonal polarizations is also considered. The signal capability of one of the antenna subarrays. These orthogonal polarizations can be linear polarizations (vertical and horizontal polarizations) or circular polarizations (right and left polarizations). Therefore, the antenna subarray under consideration supports One digital antenna port. Essentially, Corresponding to a dimension in a spatial direction (in this case, horizontal), Corresponding to another (here, vertical) spatial direction, and This corresponds to the polarization dimension. Similar considerations naturally apply to other desired dimensions (...). , Subarrays of ).

[0046] Channel State Information (CSI) Reference Signal (RS), or CSI-RS, is transmitted from the base station to inform the user equipment (UE) of the channel state of the base station's digital antenna ports. Depending on the implementation, each CSI-RS may correspond to one digital antenna port, or it may be further virtualized so that each CSI-RS can correspond to multiple (e.g., two) digital antenna ports. In other words, considering this further virtualization, the antenna elements of the base station antenna array can ultimately be used as virtualized representations of CSI-RS antenna ports. It is important to note that when the UE communicates with the base station, it treats each CSI-RS antenna port as a single transmitting element, regardless of the antenna elements it contains.

[0047] Multiple user equipments (UEs) perform measurements on the CSI-RS received from the base station, and after receiving a CSI request from the base station, the UEs calculate based on the measurements of the CSI-RS to generate the CSI. For this purpose, the UEs perform calculations on several parameters that are included in the generated CSI. Specifically, the UEs select a preferred number of MIMO layers, corresponding to the number of data streams simultaneously transmitted from the base station that the UEs intend to receive. The number of MIMO layers is reflected by the RI parameter in the CSI. Furthermore, the UEs select Discrete Fourier Transform (DFT) vectors from a predetermined codebook and thereby generate a precoding matrix (PM). The generated precoding matrix is ​​reflected by the PMI parameter within the CSI. Additionally, the UEs determine the Channel Quality Indicator (CQI) to be included in the CSI. The generated Channel State Information (CSI), including, in particular, RI, PMI, and CQI, is transmitted from the UEs to the base station as feedback channel information in response to the CSI request. Upon receiving the CSI, the base station will use the CQI to select the modulation and coding scheme (MCS) and apply the obtained precoding matrix to perform digital beamforming to perform downlink (DL) transmission (e.g., PDSCH) to the user equipment.

[0048] Aspects related to 5G NR, such as codebook implementation, CSI-RS estimation, and the calculation of the precoding matrix at the user equipment end, as well as the specific details of the representation of RI, PMI, CQI, and other parameters within CSI, are disclosed in specification TS38.214, v.18.1.0 and are also reflected in RU 2811989, the entire contents of which are incorporated herein by reference. Specifically, a Type 1 5G NR codebook can be used as this codebook (see Table 5.2.2.2.1-2 of that specification).

[0049] As can be seen from the overall discussion above, CSI-RS estimation and related operations are crucial for the required downlink (DL) transmission.

[0050] For simultaneous transmission of multiple CSI-RS in a 5G NR communication system, appropriate multiplexing of CSI-RS on resource elements (REs) is applied, where each resource element is defined by subcarriers in the frequency domain and OFDM symbols in the time domain. According to 5G NR, the system frequency band is divided into a set of subcarriers, and each of these subcarriers can be modulated with data; the total number of subcarriers depends on the system frequency band.

[0051] The key aspects related to multiplexing transmission of CSI-RS in 5G NR are shown in Figures 2-3 below.

[0052] Similar to Figure 1 , Figure 2a The image shows the antenna array of a base station, which has four antenna ports in the first spatial dimension. ) and the four antenna ports in the second spatial dimension ( ), among which Figure 2a The left side of the figure shows the antenna subarray under consideration for the first polarization, which is shaded with a left diagonal line; the right side of the figure shows the same subarray for the second polarization, which is shaded with a right diagonal line. As mentioned above, these two polarizations ( The subarrays are orthogonal to each other. Therefore, the subarrays under discussion provide support for 32 digital ports of the base station.

[0053] Figure 2a It also shows the index of the digital ports on the antenna array, as used in 5G NR, and the ordering of this index is implemented according to the following principle: "first" the first spatial dimension ( ), and then in the second spatial dimension ( ), and then the polarization dimension ( ).

[0054] Figure 2b Showing will Figure 2a The illustrated example shows a digital port mapped to a time-frequency resource. Figure 2b The diagram generally illustrates a CSI-RS pattern consisting of resource elements that provide orthogonal multiplexing of CSI-RS, where, according to the example considered, the CSI-RS is transmitted from 32 digital ports of the base station. First, as... Figure 2bAs shown, the time-frequency resources of the CSI-RS pattern are allocated to eight code division multiplexing (CDM) groups, which are regularly arranged in frequency and time. Specifically, the frequency spacing between adjacent CDM groups is one subcarrier, and the time spacing between adjacent CDM groups is one OFDM symbol. Furthermore, in each of the eight CDM groups, CSI-RS multiplexing is provided using two orthogonal coverage codes (OCCs) of length 2 in the frequency domain (FD) and two OCCs of length 2 in the time domain (TD). Therefore, the considered CSI-RS pattern enables the multiplexing of 32 CSI-RS for 32 digital ports of a base station: 8 CDM groups × 2 FD-OCCs of length 2 × 2 TD-OCCs of length 2. Accordingly, each CDM group in Figure 2b It is illustrated as consisting of four adjacent resource elements, two of which are in the frequency domain and two of which are in the time domain.

[0055] Figure 2b It also shows CSI-RS (which is actually a digital port (see...)) Figure 2a The indexes on the illustrated CSI-RS pattern are ordered according to the following principle: "First within the CDM group, then within the frequency domain, and finally within the time domain." Figure 2b In the diagram, assume that the CDM groups in the CSI-RS pattern are numbered sequentially according to a similar principle: "frequency first, then time." That is, in the diagram shown, the index of the CDM group in the upper left corner is Δ=0, the index of the CDM group in the lower left corner is Δ=3, the index of the CDM group in the upper right corner is Δ=4, and the index of the CDM group in the lower right corner is Δ=7.

[0056] It is worth noting here that, according to Figure 2b An exemplary 5G NR CSI-RS pattern is shown, where the time-frequency region is confined in frequency to a Physical Resource Block (PRB) consisting of 12 subcarriers and in time to a time slot consisting of 14 OFDM symbols. It should also be noted that, according to 5G NR, the scheduling of time-domain resources in the base station is performed at a granularity of a Transmission Time Interval (TTI), where for CSI-RS transmission, the TTI is a time slot; similarly, the granularity of frequency-domain resource scheduling in the base station is defined by the PRB.

[0057] For reference Figure 2a , Figure 2b The exemplary configurations of CSI-RS patterns discussed herein are not the only possible ones, and Table 1 below shows the CSI-RS configurations supported in 5G NR.

[0058] [Table 1]

[0059]

[0060] In Table 1, X is the number of base station ports, and ρ is the density; It is an index characterizing the time-frequency arrangement of the CDM group, where It is a frequency index (actually, the index of the subcarriers of the starting resource element of the CDM group). It is the time index (actually the index of the OFDM symbol of the starting resource element of the CDM group); Δ is the index of the CDM group in the CSI-RS pattern; It is the index of an element in the FD-OCC code sequence, and It is an index of the elements of the TD-OCC code sequence; the representation of the CDM type generally indicates the ability to arrange CDM groups in different subcarriers (FDM) and different OFDM symbols (TDM), and more specifically, corresponds to the configuration in the FD-OCC and the TD-OCC involved.

[0061] Figure 3a This shows the CSI-RS pattern corresponding to row 12 (configuration 12') of Table 1 within a time-frequency region of 1 PRB × 1 time slot. Index These represent the starting OFDM symbols for each of the four CDM groups, and the indexes are respectively... , , , These represent the starting subcarriers of the CDM group, and Δ = 0, 1, 2, 3 are the indices of the CDM group in the considered CSI-RS pattern. The CDM group type is CDM4, where two FD-OCCs of length 2 and two TD-OCCs of length 2 are used to multiplex the CSI-RS within the CDM group. Incidentally, Figure 2b The CSI-RS pattern shown corresponds to row 17 (configuration '17') in Table 1.

[0062] Density ρ characterizes the repetition rate of the corresponding CSI-RS pattern on consecutive PRBs. For example, as shown in configuration "12" in Table 1, ρ=0.5 means that the CSI-RS pattern repeats once every two PRBs. The same applies to configuration 17'. Furthermore, as specified in configuration 8' in Table 1, ρ=1 means that the corresponding CSI-RS pattern repeats once per PRB. The value ρ=3 (i.e., repeating three times in a PRB) can only occur in the case of a single port, because in this case, there is naturally no discussion about the so-called CDM group (type 'no CDM').

[0063] Figure 3bThe CDM types listed in Table 1 are shown, including CDM4 (FD2, TD2) described above. For example, for type FD-CDM2, two FD-OCCs of length 2 and one TD-OCC of length 1 are used; and for type CDM8, two FD-OCCs of length 2 and four TD-OCCs of length 4 are used respectively. The CDM group of type CDM8 will be discussed in more detail below.

[0064] For the frequency domain, using an OCC of length 2 can provide two OCC sequences (vectors). , And the elements of each FD-OCC code sequence are indexed. serial number, Similarly, using an OCC of length 4 for TD can provide four OCC sequences. , And the elements of each TD-OCC code sequence are indexed. The number, .

[0065] When using an OCC based on Walsh-Hadamard Orthogonal Cover Code (WH-OCC), the code sequence for CDM8 can have the following form: , , , , , .

[0066] According to 5G NR, each CSI-RS (and therefore each base station port) is assigned a combined OCC sequence, as shown in Table 2 below for the CDM8 case:

[0067] [Table 2]

[0068]

[0069]

[0070] In Table 2, It is an index of the CSI-RS in the CDM group (and correspondingly, the combined OCC code sequences). This index is implemented based on the assumption that the OCC sequences are applied first in terms of frequency and then in terms of time.

[0071] In summary, such as Figure 2b As shown, the index of the digital port in the CSI-RS configuration can be represented by the following formula 1:

[0072] [Formula 1]

[0073]

[0074] Where p is the index of the digital port, It is the index of the combined OCC code sequence in the CDM group. It is the length of the combined OCC code sequence (for Figure 2a The CDM group of the CSI-RS pattern shown. ), It is the index of the CDM group in the CSI-RS pattern (see Table 1). It is the number of CDM groups in the CSI-RS pattern (for Figure 2a The CSI-RS pattern shown is Formula (1) can be used to determine from which digital port p which orthogonal CSI-RS code sequence is sent. Of course, the index according to Formula (1) is known in advance on the user equipment.

[0075] According to 5G NR, CSI-RS can be transmitted from the base station in the following ways:

[0076] In a non-periodic manner, the base station transmits CSI-RS when needed, and (multiple) user equipment are informed in advance (e.g., via downlink control information (DCI)) of CSI-RS transmission in a specific time slot;

[0077] Periodically, in this case, the periodicity of the transmission is pre-configured in the base station and signaled in advance to (multiple) user equipment;

[0078] Semi-persistent, where the pre-configured execution is similar to periodic options, but the base station uses control downlink signaling (e.g., MAC messages) to activate / deactivate specific CSI-RS.

[0079] Furthermore, 5G NR provides the ability to control the bandwidth (BW) used for CSI-RS transmission; specifically, the base station can use one component carrier (CC) (one frequency channel) for this transmission, or it can use multiple CCs (multiple frequency channels). In each of these cases, CSI-RS is transmitted on each CC so that the user equipment can calculate the channel state information for each CC. The base station provides the CSI-RS parameters for each CC to the user equipment. Additionally, a QPSK sequence based on a pseudo-random noise (PN) sequence is used in CSI-RS modulation to achieve interference randomization.

[0080] The aspects related to 5G NR discussed above with reference to Tables 1 and 2 and Figures 2-3, particularly concerning time and frequency resources for mapping base station digital ports to CSI-RS patterns and the multiplexing of CSI-RS transmissions, are disclosed in specification TS38.211, version 18.1.0, the entire contents of which are incorporated herein by reference.

[0081] Although the global deployment of 5G NR systems is in its initial stages, research is already underway to standardize next-generation wireless communication systems in various directions. These systems, known as 6G, will have features that surpass those of 5G NR.

[0082] Specifically, for the 6G operating range of 8-13 GHz (upper-mid band), the plan is to support ultra-large-scale antenna arrays (e.g., composed of 3072 antenna elements) at the base station by using a hybrid analog and digital beamforming with a large number of antenna ports (≤256). Therefore, particularly by supporting up to 64 simultaneous spatial MIMO layers in the upper-mid band communication system, the concept of radio interfaces with ultra-large antenna arrays (xMIMO) will be elevated to a whole new level. Furthermore, 6G plans to support reference signal groups similar to those used in 5G NR, such as DM-RS, CSI-RS, SRS, PT-RS, and PSS / SSS.

[0083] At the same time, the methods used in 5G NR cannot always be directly extrapolated to the next generation of communication systems.

[0084] Specifically, the CSI-RS configuration for 5G NR (see Table 1) can support up to 32 digital ports, while the design requirement for 6G xMIMO is up to 256 ports. Accordingly, a new CSI-RS configuration with significantly higher capacity should be developed for 6G xMIMO.

[0085] In the context of developing CSI-RS configurations required for 6G xMIMO, an additional obstacle arises from 5G NR limiting the time-frequency region of the CSI-RS pattern to one PRB and one time slot (see...). Figure 2b , Figure 3a This includes the limitation that CDM groups can only consist of adjacent resource elements. Regarding the latter limitation, it should be noted that in addition to CSI-RS, the base station may need to transmit (multiple) other signals; however, in the context of 6G xMIMO, allocating adjacent resource elements to larger capacity CDM groups (e.g., having a greater number of adjacent OFDM symbols in the time domain compared to 5G NR) may impose unintended limitations on such transmissions.

[0086] Another aspect to consider when developing CSI-RS configurations for 6G xMIMO is as follows. Due to the significant increase in the number of digital ports at base stations, user equipment (UEs) may experience a higher computational load when estimating a large number of CSI-RS and CSI-RS ports. Therefore, UEs (e.g., UEs with limited computing power) should be able to estimate a smaller number of CSI-RS ports in a manner transparent to both the UE and the base station. However, 5G NR does not provide a mechanism for scaling (reusing) digital ports accordingly.

[0087] The purpose of this invention is to provide a configuration for multiplexing CSI-RS, which supports the required number of base station digital ports (up to 256) while avoiding the defects of the prior art.

[0088] In the context of this objective, according to a first aspect of the invention, a method for generating a Channel State Information Reference Signal (CSI-RS) is provided.

[0089] The method presented in this paper includes: in a base station of a wireless communication system, for a preset number of... The digital port used defines a CSI-RS pattern consisting of resource elements, where each resource element is defined by a subcarrier in the frequency domain and by an OFDM symbol in the time domain. This definition includes: for the CSI-RS pattern, setting adjacent elements in the frequency domain... Groups of physical resource blocks (PRBs) and those that are temporally adjacent. A group of time slots, of which , It is a natural number, and , At least one of them is greater than 1; set the quantity The CDM group, where the number is set. The CDM group includes the number of settings in the frequency domain. CDM groups and the number set in the time domain CDM group, ,in , It is a natural number; define a CDM group, where defining a CDM group includes setting an equality for that CDM group. The frequency magnitude of each subcarrier and equal to The time size of one OFDM symbol makes ,in and It is being considered for use in CDM groups. The OCC is set in the case of one CSI-RS, where the code sequence length of the OCC is... ; and settings The time-frequency arrangement of each CDM group, wherein setting the time-frequency arrangement includes setting the frequency domain CDM groups in The arrangement of PRB groups and in the time domain CDM groups in The arrangement within the time slot group. The CSI-RS pattern is repeated on the PRB group.

[0090] According to an embodiment, the arrangement of CDM groups in the frequency domain includes targeting For each of the CDM groups, set the index k of the starting subcarrier in the CSI-RS pattern, and set the arrangement of the CDM groups in the time domain including for For each of the CDM groups, set the index of the starting OFDM symbol in the CSI-RS pattern. The CSI-RS pattern repeats at a preset density. The process was carried out in which the CSI-RS pattern was repeated on each sequential group of the PRB ( ), or the CSI-RS pattern repeats only on the PRB group in those PRBs allocated in the base station for CSI-RS transmissions ( ).

[0091] According to an embodiment, the method further includes sending a message from a base station to at least one user equipment (UE) in a wireless communication system, the message including at least the following indication: , , , , , ,index The message is preferably transmitted via at least one of the following methods: DCI, MAC signaling, or RRC signaling.

[0092] According to the embodiment, the OCC is an OCC based on Walsh-Hadamard Orthogonal Cover Code (WH-OCC), where equal Where n is a non-negative integer. The WH-OCC code sequence is initially assigned to a digital port according to a predefined first application order by the base station. The digital port corresponds to the CSI-RS to be multiplexed in the CDM group, thus forming the WH-OCC code set for that CDM group. The WH-OCC code sequence is ordered within the WH-OCC code set according to the first application order. The WH-OCC code set is available in the user equipment, and the first application order has been preset in the user equipment or has been pre-signaled to the user equipment.

[0093] According to an embodiment, defining a CDM group includes defining the i-th CDM group in a family by replicating the (i-1)-th CDM group in the family at frequency or time, where i is a natural number, i>1, and if the replication is performed at frequency, then The two (i-1)th CDM groups included in the i-th CDM group of this family are preset. Separated by the interval of each subcarrier, among which It is a non-negative integer; or if the copy is performed in time, then The two (i-1)th CDM groups included in the i-th CDM group of this family are preset. Separated by the interval of OFDM symbols, where It is a non-negative integer, until equal and equal The original CDM group of this family can be a CDM group consisting of a single resource element ( , ),in and ( The value of ) can be 0, 1, or 2, where Alternatively, the original CDM of this family can be a CDM group consisting of more than one resource element, where and The value can be 0, 1, or 2. The message may further include an interval. and / or interval Indicates at least some intervals.

[0094] According to an embodiment, the index of the digital port in the CSI-RS pattern is set in the base station as follows:

[0095]

[0096] Where p is the index of the digital port; It is the sequential index of the CDM group in the CSI-RS pattern; ,in It is the index of the WH-OCC code sequence in the CDM group sorted according to the first application; It is a bitwise inversion permutation function that provides: to permutate the index The decimal representation of is converted to its binary representation, the bit order in the binary representation is reversed, and the reversed binary representation is converted to its decimal representation at index s, where the index is determined by the binary representation. Assigning WH-OCC code sequences to digital ports in the CDM group corresponds to the second application order. As described herein, this method further includes: in the base station, reordering the WH-OCC code sequences in the WH-OCC code set of the CDM group according to the second application order.

[0097] According to an embodiment, CDM groups are indexed continuously in the CSI-RS pattern according to the following principles: either "frequency first, time second" or "time first, frequency second" throughout the entire CSI-RS pattern; or "frequency first, time second" within each PRB / slot, followed by a transition between PRBs / slots according to the "time first, frequency second" principle; or "frequency first, time second" within a PRB / slot, followed by a transition between PRBs / slots according to the "frequency first, time second" principle. The first application sorting of the WH-OCC code sequences in the CDM group is preferably implemented according to the "frequency first, time second" principle.

[0098] According to an embodiment, Several digital ports are implemented in the base station's antenna array, which has a size of [missing information]. ,in It is the number of antenna ports of the array along the first spatial dimension. It is the number of antenna ports of the array along the second spatial dimension. , The base station is configured to use either a first polarization or a second polarization to perform signal transmission from each antenna port of the array, wherein the first polarization and the second polarization are orthogonal. A virtual hierarchical partitioning is used in the base station to divide the base station antenna array into subarrays, wherein in the r-th level ( The antenna array is divided into There are 3 identical subarrays. The size of each subarray is... ,in It is the number of antenna ports of the subarray along the first spatial dimension. It is the number of antenna ports of the subarray along the second spatial dimension. , , Each subarray at level r consists of two subarrays at levels (r-1), such that... or The size of the subarray in the first level (r=1) is... , , where the r-th level ( Each subarray represents the base station's... A combination port is a combination of digital ports. The CDM subgroups whose resource elements constitute part of the resource elements of the CDM group of the CSI-RS pattern, and the corresponding WH-OCC code subsets are set for each level, wherein the WH-OCC code sequence of the WH-OCC code subset is initially assigned to the combination port according to the first application order.

[0099] According to an embodiment, in the r-th level, the index of the digital port on the base station antenna array is defined as follows:

[0100] ,

[0101] Where p is the index of the digital port on the antenna array, x=0 represents the first polarization, and x=1 represents the second polarization. It is the sequential index of the subarrays in the antenna array. This refers to the sequential index of the antenna ports in the subarray. Preferably, the subarray is indexed on the antenna array according to the principle of "first dimension first, then second dimension", and the antenna ports in the subarray are indexed according to the principle of "first dimension first, then second dimension".

[0102] This hierarchical division preferably involves a maximum of two levels: r=1 and / or r=2.

[0103] According to the embodiment, the hierarchical division, the index of the digital port on the CSI-RS pattern, and the index of the digital port on the antenna array are all preset in the user equipment or transmitted to the user equipment in advance via signaling.

[0104] According to another embodiment, the message also includes information about the hierarchy, the index of the digital port on the CSI-RS pattern, and the index of the digital port on the antenna array.

[0105] According to an embodiment, the method provided herein further includes, in the user equipment: determining the level corresponding to the r-th level ( The combined port performs channel estimation, where channel estimation is performed to generate channel state information (CSI) in the user equipment; and performs channel estimation based on the CDM subgroup and WH-OCC code subset corresponding to the r-th level, where the WH-OCC code subset is reordered according to the second application sorting.

[0106] According to an embodiment, the base station is configured to perform CSI-RS transmissions simultaneously in a set of component carriers (CCs), wherein the method of the first aspect of the invention is performed for each component carrier in the set of component carriers.

[0107] According to a second aspect of the present invention, a method for generating CSI-RS is provided.

[0108] The method provided in this paper includes, in the base station of a wireless communication system, for a preset number of... The digital port used defines a CSI-RS pattern consisting of resource elements, where each resource element is defined by a subcarrier in the frequency domain and by an OFDM symbol in the time domain. This definition includes: setting the frequency domain for the CSI-RS pattern. Groups of adjacent PRBs and in the time domain A group of adjacent time slots, among which , It is a natural number; set the quantity. The CDM group, where the number is set. The CDM group includes the number of settings in the frequency domain. CDM groups and the number set in the time domain CDM group, ,in , It is a natural number; define a CDM group, where defining the CDM group includes setting it to equal to the specified value for that CDM group. The frequency magnitude of each subcarrier and equal to The time size of one OFDM symbol makes ,in and It is intended for reuse within a CDM group. The OCC is set for each CSI-RS, where the code sequence length of the OCC is [length missing]. The definition of a CDM group includes: performing the definition of the i-th CDM group of the family by replicating the (i-1)-th CDM group of the family in frequency or time, where i is a natural number, i>1, and if the replication is performed in frequency, then The i-th CDM group of this family includes two (i-1)-th CDM groups, which are connected by... Separated by a preset interval of subcarriers, among which It is a non-negative integer; or if the copy is performed in time, then The i-th CDM group of this family includes two (i-1)-th CDM groups, which are connected by... Separated by a preset interval of OFDM symbols, where It is a non-negative integer, until equal and equal And set The time-frequency arrangement of each CDM group, wherein setting the time-frequency arrangement includes setting the frequency domain CDM groups in The arrangement of each PRB within a group and in the time domain CDM groups in The arrangement within a time slot group. The CSI-RS pattern is repeated on the PRB group.

[0109] The original CDM group of this family can be a CDM group consisting of a single resource element. , ),in and ( The value of ) can be 0, 1, or 2, where Alternatively, the original CDM of this family can be a CDM group consisting of more than one resource element, where and The value can be 0, 1, or 2.

[0110] According to an embodiment, setting the arrangement of CDM groups in the frequency domain includes targeting For each of the CDM groups, set the index k of the starting subcarrier in the CSI-RS pattern, and set the arrangement of the CDM groups in the time domain including for For each of the CDM groups, set the index 1 of the starting OFDM symbol in the CSI-RS pattern. The CSI-RS pattern is repeated at a preset density. The process was carried out in which the CSI-RS pattern was repeated on each sequential group of the PRB ( ), or the CSI-RS pattern repeats only on the PRB group in those PRBs allocated in the base station for CSI-RS transmissions ( ).

[0111] According to an embodiment, the method further includes: sending a message from a base station to at least one user equipment in a wireless communication system, the message including at least the following indications: , , , , , ,index At least some indexes, intervals and / or interval At least some intervals in The message is preferably transmitted via at least one of the following methods: DCI, MAC signaling, or RRC signaling.

[0112] According to the embodiment, the OCC is WH-OCC, wherein equal Where n is a non-negative integer. The WH-OCC code sequence is initially assigned to digital ports according to a predefined first application order by the base station. These digital ports correspond to the CSI-RS to be multiplexed in the CDM group, thus forming the WH-OCC code set for that CDM group. The WH-OCC code sequence is ordered within the WH-OCC code set according to the first application order. The WH-OCC code set can be used in the user equipment, and the first application order has been preset in the user equipment or has been pre-signaled to the user equipment.

[0113] According to an embodiment, the index of the digital port in the CSI-RS pattern is set in the base station as follows:

[0114] ,

[0115] Where p is the index of the digital port; It is the sequential index of the CDM group in the CSI-RS pattern; ,in It is the index of the WH-OCC code sequence in the CDM group sorted according to the first application; It is a bitwise inversion permutation function that provides: to permutate the index The decimal representation is converted to a binary representation, the bit order in the binary representation is reversed, and the reversed binary representation is converted to a decimal representation of index s, where the assignment of the WH-OCC code sequence to the digital port in the CDM group according to index {s} corresponds to the second application order. This method also includes: in the base station, reordering the WH-OCC code sequences in the WH-OCC code set of the CDM group according to the second application order.

[0116] According to an embodiment, , At least one of them is greater than 1, wherein the CDM group is indexed continuously in the CSI-RS pattern according to the following principles: "frequency first, time second" throughout the entire CSI-RS pattern, or "time first, frequency second" throughout the entire CSI-RS pattern; or "frequency first, time second" within each PRB / slot, followed by a transition between PRBs / slots according to the principle of "time first, frequency second"; or "frequency first, time second" within a PRB / slot, followed by a transition between PRBs / slots according to the principle of "frequency first, time second". The first application sorting of the WH-OCC code sequence in the CDM group is preferably implemented according to the principle of "frequency first, time second".

[0117] According to an embodiment, Several digital ports are implemented in the base station's antenna array, which has a size of [missing information]. ,in It is the number of antenna ports of the array along the first spatial dimension. It is the number of antenna ports of the array along the second spatial dimension. , The base station is configured to use either a first polarization or a second polarization to perform signal transmission from each antenna port of the array, wherein the first polarization and the second polarization are orthogonal. A virtual hierarchical partitioning is used in the base station to divide the base station antenna array into subarrays, wherein in the r-th level ( The antenna array is divided into There are 10 identical subarrays, and each subarray has a size of 1. ,in It is the number of antenna ports of the subarray along the first spatial dimension. It is the number of antenna ports of the subarray along the second spatial dimension. , , Each subarray of the r-th level consists of two... The hierarchical subarray structure makes or , where the r-th level The subarray size is , , where the r-th level ( Each subarray represents the base station's... A combined port is a combination of digital ports. The CDM subgroups whose resource elements constitute part of the resource elements of the CDM group in the CSI-RS pattern, and the corresponding WH-OCC code subsets, are set for each level, wherein the WH-OCC code sequence of the WH-OCC code subset is initially assigned to the combined port according to the first application order. Therefore, this CDM subgroup can represent at least some CDM groups within a family of CDM groups.

[0118] According to an embodiment, in the r-th level, the index of the digital port on the base station antenna array is defined as follows:

[0119] ,

[0120] Where p is the index of the digital port on the antenna array, x=0 represents the first polarization, and x=1 represents the second polarization. It is the sequential index of the subarrays in the antenna array. This refers to the sequential index of the antenna ports in the subarray. Preferably, the subarray is indexed on the antenna array according to the principle of "first dimension first, then second dimension", and the antenna ports in the subarray are indexed according to the principle of "first dimension first, then second dimension".

[0121] This hierarchical division preferably involves a maximum of two levels: r=1 and / or r=2.

[0122] According to the embodiment, the hierarchical division, the index of the digital port on the CSI-RS pattern, and the index of the digital port on the antenna array are all preset in the user equipment or transmitted to the user equipment in advance via signaling.

[0123] According to another embodiment, the message also includes information about the hierarchy, the index of the digital port on the CSI-RS pattern of the port, and the index of the digital port on the antenna array.

[0124] According to an embodiment, the method further includes in the user equipment: determining the level corresponding to the r-th level ( The combined port performs channel estimation, where channel estimation is to be performed to generate CSI in the user equipment; and performs channel estimation based on the CDM subgroup and WH-OCC code subset corresponding to the r-th level, where the WH-OCC code subset is reordered according to the second application sorting.

[0125] According to an embodiment, the base station is configured to perform CSI-RS transmissions simultaneously in a set of component carriers, wherein the method of the second aspect of the invention is performed for each component carrier in the set of component carriers.

[0126] According to a third aspect of the present invention, a method for generating CSI-RS in a wireless communication system including a base station is provided, wherein a preset number of The digital ports used are implemented in the antenna array of the base station, wherein a hierarchy of combined ports is used in the base station, wherein each combined port in the corresponding hierarchy combines a corresponding preset number of digital ports of the base station.

[0127] The method includes defining a CSI-RS pattern composed of resource elements (REs) in a base station, wherein each resource element is defined by a subcarrier in the frequency domain and by an OFDM symbol in the time domain. The definition includes, for the CSI-RS pattern: setting the frequency domain... Groups of adjacent PRBs and in the time domain A group of adjacent time slots, among which , All are natural numbers; set the quantity. The CDM group, where the number is set. The CDM group includes the number of settings in the frequency domain. CDM groups and the number set in the time domain CDM group, ,in , All are natural numbers; define a CDM group, where defining a CDM group includes setting the parameters for the CDM group. The frequency magnitude of each subcarrier is equal to and equal to The time size of each OFDM symbol is equal, making Among them, those to be used in CDM group reuse The OCC of each CSI-RS is equal to the code sequence length of the WH-OCC. The WH-OCC; the WH-OCC code sequence is initially assigned to the digital port according to the first application order predefined in the base station, thus forming the WH-OCC code set of the CDM group, wherein the WH-OCC code sequence is ordered in the WH-OCC code set according to the first application order; setting The time-frequency arrangement of each CDM group, wherein setting the time-frequency arrangement includes setting the frequency domain CDM groups in The arrangement of each PRB within a group and in the time domain CDM groups in The arrangement within a time slot group; and for each level, setting a CDM subgroup, which is a portion of the resource elements of the CDM group constituting the CSI-RS pattern, and a corresponding WH-OCC code subset, wherein the WH-OCC code sequence of the WH-OCC code subset is initially assigned to the combination port according to the first application order. The CSI-RS pattern is repeated on the PRB group.

[0128] The method further includes, in a base station, reordering the WH-OCC code sequences in the WH-OCC code set in the CDM group according to a second application sorting defined by applying bit reversal permutation to the corresponding index of the WH-OCC code sequence in the CDM group, wherein the index corresponds to the first application sorting; and transmitting information of the defined CSI-RS pattern from the base station to at least one user equipment in the wireless communication system.

[0129] The method then includes performing channel estimation in the user equipment for the combined port corresponding to the specific level based on the CDM subgroup and WH-OCC code subset corresponding to the specific level, wherein the WH-OCC code subset is reordered according to a second application sorting.

[0130] According to an embodiment, the base station is configured to transmit signals from each antenna port of the array using either a first polarization or a second polarization, wherein the first polarization and the second polarization are orthogonal. This hierarchy is generated by dividing the base station antenna array into subarrays, wherein in the r-th level ( The antenna array is divided into There are 10 identical subarrays, and each subarray has a size of 1. ,in It is the number of antenna ports of the subarray along the first spatial dimension. It is the number of antenna ports of the subarray along the second spatial dimension. , , Each subarray at level r consists of two subarrays at levels (r-1), such that... or The size of the subarray in the first level (r=1) is... , , where the r-th level ( Each subarray represents the base station's... A combination port that combines several digital ports together.

[0131] This hierarchical division preferably involves a maximum of two levels: r=1 and / or r=2.

[0132] According to an embodiment, setting the arrangement of CDM groups in the frequency domain includes targeting For each of the CDM groups, set the index k of the starting subcarrier in the CSI-RS pattern, and set the arrangement of the CDM groups in the time domain including for For each of the CDM groups, the index l of the starting OFDM symbol in the CSI-RS pattern is set. The repetition of the CSI-RS pattern is performed at a preset density ρ, wherein the CSI-RS pattern is repeated on each sequential group of the PRB ( ), or the CSI-RS pattern repeats only on the PRB group in those PRBs allocated in the base station for CSI-RS transmissions ( ).

[0133] According to an embodiment, information regarding the CSI-RS pattern includes at least the following indications: , , , , , ,index The signaling is preferably executed by at least one of the following methods: DCI, MAC signaling, or RRC signaling.

[0134] According to an embodiment, the information regarding the CSI-RS pattern further includes information about the hierarchy. The WH-OCC code set can be used in the user equipment, and the first application order has been preset in the user equipment or has been pre-signaled to the user equipment.

[0135] According to an embodiment, defining a CDM group includes: defining the i-th CDM group in a family by replicating the (i-1)-th CDM group in the family at frequency or time, where i is a natural number, i>1, wherein if the replication is performed at frequency, then The i-th CDM group in this family contains two (i-1)-th CDM groups, which are preset. Separated by the interval of each subcarrier, among which It is a non-negative integer; or if the copy is performed in time, then The i-th CDM group in this family contains two (i-1)-th CDM groups, which are preset. Separated by the interval of OFDM symbols, where It is a non-negative integer, until equal and equal This CDM subgroup corresponds to at least some CDM groups within a family of CDM groups. The original CDM group of this family can be a CDM group consisting of a single resource element. , ),in and The value of (i>2) can be 0, 1, or 2, where Alternatively, the original CDM of this family can be a CDM group consisting of more than one resource element, where and The value can be 0, 1, or 2. Information about the CSI-RS pattern may further include the interval { } and / or interval { }.{ Indication of at least some intervals in}.

[0136] According to an embodiment, the index of the digital port in the CSI-RS pattern is set in the base station as follows:

[0137] ,

[0138] Where p is the index of the digital port; It is the sequential index of the CDM group in the CSI-RS pattern; ,in It is the index of the WH-OCC code sequence in the CDM group sorted according to the first application; It is a function that performs bit reversal permutations, providing the following: index... The decimal representation is converted to a binary representation, the bit order in the binary representation is reversed, and the reversed binary representation is converted to a decimal representation of index s, where the WH-OCC code sequence is assigned to the digital port in the CDM group according to index {s}, corresponding to the second application order.

[0139] According to an embodiment, , At least one of them is greater than 1, wherein the CDM group is indexed continuously in the CSI-RS pattern according to the following principles: "frequency first, time second" throughout the entire CSI-RS, or "time first, frequency second" throughout the entire CSI-RS; or "frequency first, time second" within each PRB / slot, and then transitioning sequentially between PRBs / slots according to the principle of "time first, frequency second"; or "frequency first, time second" within a PRB / slot, and then transitioning between PRBs / slots according to the principle of "frequency first, time second". The first application sorting of the WH-OCC code sequence in the CDM group is preferably implemented according to the principle of "frequency first, time second".

[0140] According to an embodiment, in the r-th level, the index of the digital port on the base station antenna array is defined as follows:

[0141] ,

[0142] Where p is the index of the digital port on the antenna array, x=0 represents the first polarization, and x=1 represents the second polarization. It is the sequential index of the subarrays in the antenna array. This refers to the sequential index of the antenna ports in the subarray. Preferably, the subarray is indexed on the antenna array according to the principle of "first dimension first, then second dimension", and the antenna ports in the subarray are indexed according to the principle of "first dimension first, then second dimension".

[0143] According to an embodiment, the information about CSI-RS also includes information about the index of the digital port on the CSI-RS pattern and the index of the digital port on the antenna array.

[0144] According to an embodiment, the base station is configured to perform CSI-RS transmissions simultaneously in a set of component carriers (CCs), wherein the method of the third aspect of the invention is performed for each component carrier in the set of component carriers.

[0145] According to a fourth aspect of the present invention, a base station in a wireless communication system is provided, the base station comprising at least: a transceiver unit; a data processing unit; and a data storage unit storing computer-executable code, wherein when the computer-executable code is executed by the data processing unit, the base station performs the method of either the first or second aspect of the present invention.

[0146] According to a fifth aspect of the present invention, a computer-readable medium storing computer-executable code is provided, wherein when the computer-executable code is executed by a data processing unit of a base station (BS) in a wireless communication system, it causes the base station to perform a method of either the first or second aspect of the present invention.

[0147] According to a sixth aspect of the present invention, a wireless communication system is provided, the wireless communication system comprising at least a base station, the base station comprising at least: a transceiver unit; a data processing unit; and a data storage unit, wherein the base station is configured to communicate with a user equipment comprising at least the following: the transceiver unit; the data processing unit; and the data storage unit, wherein the data storage unit of the base station stores computer-executable code, and the data storage unit of the user equipment also stores computer-executable code, wherein when the computer-executable code is executed by the data processing unit of the base station and the user equipment, the method according to a third aspect of the present invention is performed.

[0148] The technical results achievable by this invention are as follows. The CSI-RS configuration proposed in this paper provides support for the number of digital ports required to meet the design requirements of next-generation communication systems, while providing the ability to systematically form CDM groups and arrange them in time and frequency on PRB / time slot groups. It offers greater flexibility in allocating time and frequency resources to each CDM group and has the ability to nest and scale CSI-RS ports in a manner transparent to base stations and user equipment.

[0149] The following description refers to exemplary embodiments of the invention, which are illustrated in the accompanying drawings, in which the same reference numerals denote similar elements. It should be understood that embodiments of the invention may take various forms and should not be considered as limited to the description herein. Therefore, these exemplary embodiments will be described below in conjunction with the illustrations to elucidate the core aspects of various aspects of the invention.

[0150] Figure 4 A full view of a wireless communication system in which aspects of the invention can be implemented is shown. Figure 4 As shown, User Equipment (UE) 401 communicates with Base Station (BS) 402 in Radio Access Network (RAN) 400. UEs 401 (e.g., UEs 401-1, 401-2, 401-3, etc.) are distributed across RAN 400, and each UE 401 can be fixed or mobile. Well-known examples of UEs include smartphones, tablets, modems, etc.

[0151] Base station 402 (e.g., BS 402-A, 402-B, 402-C) can provide coverage for a specific geographical area, commonly referred to as a "cell". Base station 402 is generally of a fixed structure, but can also have mobile implementations. Generally, a base station can represent a macro base station (e.g., ... Figure 4 The base stations 402-A, 402-B, and 402-C shown in the diagram can also represent pico base stations used for pico cells or femtocells. A cell can be further divided into several sectors.

[0152] Coordination and management of base station 402 can be provided by a network controller communicating with it (e.g., via a backhaul connection). RAN 400 can communicate with the core network (CN) that provides various network functions, such as access and mobility management, session management, authentication server functions, application functions, etc. (e.g., via the network controller). Furthermore, base stations 402 in RAN 400 can also be interconnected, for example, via a direct physical connection, preferably a high-speed connection.

[0153] When a user equipment (UE) moves within RAN 400, it can switch from one base station to another. For example, UE 401-3 can switch from BS 402-B to BS 402-A. When this is done, the UE's corresponding operating parameters are reconfigured to perform operations with the new base station. UEs can also switch between sectors of a base station.

[0154] In the wireless communication system under consideration, user equipment (UE) is able to interact with a group of interconnected base stations, and this interaction does not only occur when UE switches base stations. One of the base stations in the group is the serving base station of the UE, and the various aspects of the coordinated operation of the base stations in the group during this interaction can be implemented centrally (e.g., through a network controller) and / or by the serving base station.

[0155] In 5G NR wireless communication systems, the Cloud RAN (C-RAN) concept is implemented. This concept refers to dividing the base station into three parts and exchanging information between these functional parts using defined special interfaces. Specifically, the base station can be divided into a Radio Unit (RU) responsible for radio transceiver functions, a Distributed Unit (DU) for L1 (Physical Layer) and L2 (Media Access Control (MAC) Layer) computations, and a Central Unit (CU) for L2 and L3 (Radio Resource Control (RRC) Layer) computations. This division allows for the centralization of CUs in the corresponding central network nodes, while DUs can be distributed across a wider range of cell nodes. In this configuration, connection handover between cell nodes can occur at the L1 layer, meaning relatively low latency. Support for this concept is also expected in 6G wireless communication networks.

[0156] It should be noted that, according to Figure 4 The description and the figures themselves are merely illustrative and non-limiting in nature, intended to outline the general operating environment of the invention. Although Figure 4 Only the basic components of a communication system are shown, but it should be understood that a communication system may also include several other elements.

[0157] Figure 4Each of the BS 402 shown includes hardware and logic components for implementing its respective function in the base station. The hardware components specifically refer to antenna arrays composed of the transceiver antenna elements discussed above, processors with various special configurations, controllers, data storage devices, other circuit elements, and the buses connecting them. The logic components refer to the software stored in the corresponding storage devices and configuring the corresponding circuit elements. Firmware directly hardwired within the processor and controller also refers to software. The aforementioned hardware components are specifically configured to perform various processes related to the transmitted and received signals, including (de)modulation, (de)multiplexing, encoding (decoding), amplification, filtering, digitization, (de)interleaving, resource allocation, and receive / transmit scheduling.

[0158] Similarly, Figure 4 Each of the UES 401 shown includes hardware and logic components for implementing its respective functions within the user equipment. The hardware components specifically refer to transceiver devices with corresponding antenna elements, processors (multiple) with various specially configured configurations, controllers, data storage devices, other circuit elements, and the buses connecting them. The logic components refer to the software stored in the corresponding storage devices and configuring the corresponding circuit elements. Firmware directly hardwired within the controller also refers to software. The aforementioned hardware components are specifically configured to perform various processes related to transmitted and received signals, including (de)modulation, (de)multiplexing, encoding (decoding), amplification, filtering, digitization, and (de)interleaving. Furthermore, the UE includes components for user interaction, including a touchscreen, speaker / microphone, buttons, and user applications stored in the UE's memory and executed by the UE's processor within the corresponding operating system.

[0159] Examples of the aforementioned processors / controllers include microprocessors, microcontrollers, digital signal processors (DSPs), field-programmable gate arrays (FPGAs), discrete hardware integrated circuits, etc. The firmware / software executed by the processor / controller should be broadly understood as computer-executable instructions, instruction sets, program code, code segments, subroutines, program modules, objects, procedures, etc. The software is stored in appropriate computer-readable media, such as random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), solid-state storage devices, magnetic storage devices, optical storage devices, etc. These media can record the corresponding program code and data structures and can be accessed by the corresponding processor / controller.

[0160] As listed above, the hardware and software components of the base station and user equipment are configured to perform the methods described below in this application within the base station and user equipment. The implementation of the component hardware elements of the base station (BS) and user equipment (UE), and their specific configurations, including through corresponding logical components, are known in the art to which this application pertains. Furthermore, according to the methods of this application, various functions can be performed in multiple independent elements or in one or more integral elements, as defined by the design architecture characteristics.

[0161] According to one aspect of the technical objective involved in implementing this invention, namely, providing a configuration for CSI-RS multiplexing to support the number of base station digital ports required to meet the design requirements of next-generation communication systems, an extension for forming CSI-RS patterns to PRB groups and / or time slot groups is provided. It should be noted that, according to 5G NR, all possible CSI-RS configurations (see Table 1) are limited to one PRB and one time slot in the time-frequency domain.

[0162] Figures 5a-5c An exemplary CSI-RS pattern obtained by extension forming according to the aspects discussed in this invention is shown.

[0163] Figure 5a The diagram shows a CSI-RS pattern that occupies two PRBs in the frequency domain. And it occupies two time slots in the time domain, namely This pattern comprises eight regularly arranged CDM groups: ( ): in frequency And in terms of time Each of the CDM groups comprises 32 resource elements: eight CDM groups in frequency (i.e., Multiply by the four CDM groups in time (i.e.) ).index , Indicates the starting subcarrier of the CDM group, where and ;index Indicates the starting OFDM symbol of the CDM group, where , , and .index The set generally specifies the time-frequency arrangement of the CDM group in the CSI-RS pattern under consideration.

[0164] Similar to the above, based on Table 2 and Figure 3a , Figure 3b , Figure 3b For 5G NR considerations, 32 OCC code sequences of length 32 are used respectively according to Figure 5a CSI-RS is orthogonally multiplexed in the CDM group of the CSI-RS pattern. Therefore, according to Figure 5a The CSI-RS pattern enables the reuse of 256 CSI-RS, and correspondingly supports 256 digital ports of the base station, i.e., N. P =256.

[0165] Figure 5b The CSI-RS pattern is shown in a similar form, which occupies a frequency domain. A PRB and occupying time domain One time slot. This configuration includes three CDM groups: ( ): in frequency And in terms of time Each of the CDM groups consists of 64 resource elements ( Composed of ) Index Again, the starting subcarrier of the CDM group is represented, where and index Again, the starting OFDM symbol of the CDM group is indicated, where , and Here, a sequence of 64 OCC codes of length 64 is used according to... Figure 5b The CSI-RS in the CDM group of the orthogonally multiplexed CSI-RS pattern, and therefore, the illustrated CSI-RS pattern supports 192 digital ports: .

[0166] Figure 5c This illustrates a schematic CSI-RS pattern, which occupies... PRB and Each time slot. The illustrated CSI-RS configuration includes eight CDM groups: ( ): in frequency And in terms of time Each of the CDM groups consists of 16 resource elements ( Composed of ) Index Indicates the starting subcarrier of the CDM group, index Indicates the starting OFDM symbol of the CDM group. Accordingly, a 16-character OCC code sequence of length 16 is used to determine the starting OFDM symbol. Figure 5c The CSI-RS in the CDM group of orthogonally multiplexed CSI-RS patterns, and therefore, this CSI-RS configuration supports 128 base station digital ports: .

[0167] According to Figures 5a-5c Of all the instances considered, two PRBs ( ) groups and / or two time slots ( The group of elements has been used to form CSI-RS patterns according to the present invention. It should be noted herein that while this embodiment is preferred, it is not the only possible one, and other embodiments are also provided by the present invention, wherein... And / or .

[0168] According to a preferred embodiment of the present invention, based on Figures 5a-5c The CSI-RS pattern of any one of them is repeated on each sequential group of the PRB, that is, its density ρ is equal to 1. For example, according to this embodiment, Figure 5a The CSI-RS configuration will be in the next two ( The frequency is completely repeated in a group of PRBs. However, this preferred embodiment is not unique, and as in 5G NR, the invention also provides options for lower repetition frequencies, that is, when the density is less than 1. Examples of such alternatives are repeating the CSI-RS pattern only in those PRBs specifically allocated in the base station for CSI-RS transmissions within the PRB group.

[0169] The above diagram illustrates the significant increase in capacity of the CSI-RS pattern constructed using extensions to PRB groups and / or time slot groups, thereby supporting the required number of digital ports to meet the requirements of next-generation communication systems.

[0170] Of course, the parameters of the CSI-RS pattern selected for use in the base station should be signaled to the user equipment(s) served by the base station so that the user equipment(s) can correctly receive and estimate the CSI-RS sent from the base station. For this purpose, a control message can be sent from the base station to the user equipment(s) before CSI-RS transmission. This message includes an indication of at least the characteristics of the CSI-RS configuration used, such as... , , , , , , , It should be noted that the information may include an indication, which is not the entire set of starting subcarriers and starting OFDM symbols. (It is usually implied to be an index of each of the CDM groups containing CSI-RS) The indication is not a directive for the entire set, but rather an indication for only a portion of the set (e.g., the same index). and / or It can be included without repetition (see...) Figure 5a(See description). Control messages can be sent via DCI, MAC signaling, RRC signaling, or a combination thereof, as such embodiments should be known to those skilled in the art, and the present invention is not limited thereto.

[0171] from Figures 5a to 5c As can be seen from the provided illustrations and related discussions, due to the large number of supported base station digital ports, the number of OCC code sequences allocated to each member of the CDM group in the CSI-RS pattern is also large, resulting in a considerable size of the CDM group. The arrangement of resource elements in the time-frequency domain of these CDM groups according to the aforementioned 5G NR method, specifically in a continuous manner, causes the CDM group to occupy a large amount of time and / or frequency resources in a bundle. As mentioned above, in addition to CSI-RS, the base station may need to transmit (multiple) other signals, and occupying such a large amount of resource bundles may lead to undesirable limitations on required non-CSI-RS transmissions.

[0172] In view of the limitations considered, another aspect of the present invention provides a systematic method for constructing a CDM group of CSI-RS patterns, thereby alleviating the limitations of the prior art described above.

[0173] Figure 6a The basic principle of the proposed system approach is illustrated through an example of a family of CDM groups. Specifically, the family of CDM groups is formed iteratively, where in the i-th iteration, the i-th CDM group of the family is determined by replicating the (i-1)-th CDM group of the family in terms of frequency or time. If this replication is performed in terms of frequency (in... Figure 6a (represented by the letter F' in Chinese), then ,in This defines the number of subcarriers representing the frequency size of the j-th CDM group in the considered CDM group family; if replication is performed in time (in... Figure 6a (represented by the letter T' in Chinese), then ,in This is the number of OFDM symbols defining the time size of the j-th CDM group in the CDM group family. The dashed arrows in this diagram represent the repetitions described. Figure 6a The original CDM group of the CDM group family shown is composed of a resource unit ( , A CDM group is composed of ( ). The general principle can be expressed as follows: In a family of CDM groups, any smaller CDM group is a subset (subgroup) of any larger CDM group.

[0174] The above iterations can be performed until... equal to target size and equal to target size This allows for the formation of the desired CDM group using the current system approach. It should be understood that the explicit choice of a CDM group consisting of a single resource element as the starting point for forming a family of CDM groups does not constitute a limitation on the method. For example, one could choose a group corresponding to... , , The CDM group serves as the starting point.

[0175] Figure 6a The overall system approach demonstrated enables flexible organization of CDM groups across time-frequency resources, including on non-contiguous resource elements. This aspect in... Figure 6b The middle part is shown in general.

[0176] Figure 6b The CDM group family shown is formed iteratively in a manner similar to... Figure 6a The situation is similar, but in the third iteration (i=3), a subcarrier spacing is introduced between two CDM groups copied from the frequencies of the previous iteration (i=2) (which form the current CDM group (third iteration) according to the proposed system method). This construction of discontinuous CDM groups... Figure 6b This continues in subsequent iterations until the last one (i=6).

[0177] As the foundation supporting the system approach discussed, and Figure 6a The general principles have already been expressed in the publicly available content, taking into account... Figure 6b In this case, the extension of aspects of the invention is as follows: the family of CDM groups is formed iteratively, wherein in the i-th iteration, the i-th CDM group of the CDM group family is defined by replicating the (i-1)-th CDM group in frequency or time, and if such replication is performed in frequency, then And the two (i-1)th CDM groups in the i-th CDM group are connected by The subcarriers are separated by a predetermined interval, and if replication is performed in time, then And the two (i-1)th CDM groups in the i-th CDM group are connected by Separated by a predetermined interval between OFDM symbols. See below for reference. Figure 6b The above, , ; .

[0178] It should be understood that, Figure 6bEssentially intended to generally demonstrate the ability to form CDM groups on non-adjacent resource elements, an ability achieved by the system method provided by this invention; however, in practice, a CSI-RS pattern having such equally spaced CDM groups may be impractical.

[0179] Figure 6c It is shown in a non-restrictive manner that references have been made. Figure 6b The overall discussion focuses on the method's potential practical applications. Figure 6c It can be seen that, similar to Figure 6a As shown, until the last iteration (i=7), the CDM group of the previous iteration is copied in a continuous manner to form the CDM group of the current iteration (i.e., Furthermore, an OFDM symbol interval will only be introduced between CDM groups copied from iteration i=6 if the CDM group family being formed in the last iteration becomes very large. The resources corresponding to this interval can be separately scheduled by the base station for the transmission of other signals unrelated to the CSI-RS transmission under consideration, or even for transmission to another user equipment.

[0180] It needs to be emphasized that, such as Figure 6b , Figure 6c The intervals used in the middle are equal to 0 or 1. and The value of is not the only possible choice, and the interval can also have other values ​​(e.g., 2). This does not impose any limitation on the invention.

[0181] Based on the above discussion, the system method for forming a family of CDM groups according to the present invention is known in advance to the user equipment, while the base station sets intervals respectively when forming CDM groups for transmitting CSI-RS patterns to (multiple) user equipments. } and / or interval { The signaling is transmitted from the base station to the user equipment in advance. Specifically, in Figures 5a to 5c The control messages mentioned in the discussion may further include { }、{ All or some of the indications in} (e.g., the indication of zero spacing may be omitted).

[0182] It is important to note that this signaling can also be implemented implicitly. More specifically, two or more patterns of CDM groups of the same size can be predefined in the system, where different CDM group patterns can differ in the presence and value of the interval. In this case, the signaling is generally executed by configuring the corresponding pattern of the CDM group in the user equipment.

[0183] The following discussion relates to a systematic method for generating OCC code sequences for a CDM group forming a CSI-RS pattern according to the present invention. OCCs based on Walsh-Hadamard Orthogonal Covering Codes (WH-OCC) are preferably used as OCCs. However, this does not limit the invention, and those skilled in the art should recognize that other OCCs providing orthogonal multiplexing of CSI-RS in a CDM group can also be used within the considered technical context.

[0184] The general principle generated is essentially similar to the general principle of the above-mentioned system approach, and this general principle is described by formula (2):

[0185] [Formula 2]

[0186]

[0187] According to formula (2), WH-OCC code sequences The set is assigned to the corresponding CDM group within the family of CDM groups, where the length of each code sequence is 1. , as reference Figures 6a to 6c As shown, where It is the index of the WH-OCC code sequence in the considered CDM group, thus forming the WH-OCC code set of that CDM group. . The size is The square matrix. Furthermore, it can be seen from formula (2) that the matrix of the WH-OCC code set in the considered CDM group is... The matrix is ​​the WH-OCC code set of the previous CDM group in the CDM group family. Formed, in which the matrix The dimensions are respectively The original matrix of the family of WH-OCC code sets described is

[0188] [Formula 3]

[0189]

[0190] The families of WH-OCC code sets formed according to the methods described in formulas (2) and (3) above are shown in Table 3.

[0191] [Table 3]

[0192]

[0193] In Table 3, the top row shows the number of WH-OCC code sequences for the corresponding CDM group ( The left column shows the indices of the WH-OCC code sequences in the CDM group ( ),and corresponding The portion is in bold. Based on the previously discussed systematic construction method for the WH-OCC code set of the corresponding CDM group, the results again show that any smaller WH-OCC code set is a subset of any larger WH-OCC code set.

[0194] For example, in Figures 6a to 6c Among the families of CDM groups shown, according to the fourth column of Table 3 (for... The WH-OCC code set will correspond to any CDM group from the CDM group of iteration i=3, and according to the fifth column of the table (for The WH-OCC code set of ) corresponds to any CDM group from the CDM group of iteration i=4.

[0195] Similar to the system method for forming families of CDM groups according to the present invention, the system method for forming families of WH-OCC code sets is also known in advance at the user equipment. If the user equipment has information about a specific CDM group of families of CDM groups used in the CSI-RS pattern in use, the user equipment will also be aware of the WH-OCC code set of that CDM group.

[0196] As described above, due to the significant increase in the number of base station digital ports that need to be supported in next-generation communication systems, the computational load on user equipment associated with estimating a large number of CSI-RSs may increase. One objective of this invention is to enable user equipment to estimate a smaller number of CSI-RSs with acceptable estimation quality and in a manner transparent to both the user equipment and the base station. In the context of achieving this objective, another aspect of the invention is described below, which refers to hierarchically scaling the digital ports of a base station using the systematic method disclosed above for forming CDM sets and WH-OCC code sets.

[0197] The following text will combine Figure 7a , Figure 7b Let's discuss an exemplary scenario: In a next-generation wireless communication system supporting carrier aggregation (CA), a base station serves multiple user equipments (UEs). Each UE has certain limitations when performing channel estimation to generate a precoding matrix, ensuring that the UE can perform the aforementioned estimation on all component carriers (CCs) for no more than 256 digital ports (i.e., no more than 256 CSI-RSs). As mentioned earlier, this limitation is likely due to the computational capabilities of the UEs. The base station is configured to transmit CSI-RS from 256 digital ports on each of the CCs.

[0198] Assuming a user equipment (UE1) is configured with a CC (i.e., without a CA), then the UE1 can estimate all CSI-RS transmitted by the base station from 256 digital ports in this frequency channel.

[0199] Furthermore, suppose another user equipment (UE2) is configured to perform transmissions simultaneously on two frequency channels (i.e., two CCs) by the base station. In this case, UE2 can only perform channel estimation for a maximum of 128 ports on each of the two CCs.

[0200] Finally, suppose another user equipment (UE3) is configured on four CCs. In this case, UE3 will have to allocate its computational budget across the four frequency channels, that is, allocate its computational resources on each of the CCs. UE3 can only perform channel estimation for no more than 64 ports: 64 ports on the first CC, 64 ports on the second CC, 64 ports on the third CC, and 64 ports on the fourth CC.

[0201] Figure 7a One possible method is shown, in which different CSI-RS sets are transmitted from the base station for different numbers of ports, and the base station instructs each of UE1, UE2, and UE3 in advance which CSI-RS set to perform the estimation for. Figure 7a In the diagram, the CSI-RS set sent for 256 digital ports (UE1) is shown in black, the CSI-RS set for 128 ports (UE2) is shown in dark gray, and the CSI-RS set for 64 ports (UE3) is shown in light gray.

[0202] At the same time, refer to Figure 7a The method discussed is very resource-intensive, meaning it is associated with a significant consumption of computing resources in the base station.

[0203] In the context of the exemplary scenario under consideration, Figure 7b An alternative method according to the invention is shown, wherein a set of CSI-RS from all 256 digital ports is transmitted from the base station at each of the CCs, but by scaling the digital ports according to the aspects described in the invention, the user equipment is able to perform estimation for a correspondingly smaller number of CSI-RSs. Figure 7b This illustrates how a single CSI-RS set is sent as having nested characteristics: such as Figure 7aAs shown, the light gray rectangle represents a subset of CSI-RS for 64 ports. This light gray rectangle is implied to overlap with a wider dark gray rectangle, which represents a subset of CSI-RS for 128 ports. The dark gray rectangle is further implied to overlap with a wider black rectangle, which represents a set of CSI-RS for 256 ports. In other words, any subset of CSI-RS for a smaller number of ports is a subset of any CSI-RS(sub)set for a larger number of ports. Accordingly, as... Figure 7b Overall, the method proposed in this invention does not require additional computational overhead associated with transmissions of different CSI-RS sets.

[0204] The method for hierarchical port scaling according to the present invention will be described in more detail below with reference to Figures 8 to 10. The method essentially relies on dividing the virtual hierarchy of the base station antenna array into subarrays.

[0205] Generally, the hierarchical division is implemented as follows.

[0206] Assumption The digital ports are implemented on the base station's antenna array, which has a size of [missing information]. ,in It is the number of antenna ports of the array in the first spatial dimension. It is the number of antenna ports of the array in the second spatial dimension, and according to the above, The base station is configured to transmit signals from each antenna port of the antenna array having one of a first polarization and a second polarization (p=2), wherein the first polarization and the second polarization are orthogonal; accordingly, or In the r-th level ( The antenna array is divided into There are 3 identical subarrays, each with a size of 1. ,in It is the number of antenna ports of the subarray in the first spatial dimension. It is the number of antenna ports of the subarray in the second spatial dimension. Accordingly, , The property of the partition discussed is that each subarray of the r-th level consists of two subarrays of the (r-1)-th level, such that... or The size of the subarray in the lowest first level (r=1) is , The rth level ( Each subarray represents a combined port, which combines the base station's... The digital ports are combined together.

[0207] According to an embodiment, in the r-th level, the index of the digital port on the base station antenna array is defined by the following formula 4:

[0208] [Formula 4]

[0209]

[0210] Where p is the index of the digital port on the antenna array, x=0 represents the first polarization, and x=1 represents the second polarization. It is the sequential index of the subarrays in the antenna array. This is the sequential index of the antenna ports in the subarray. In each level of this partitioning hierarchy, the subarray is indexed on the antenna array according to the principle of "first dimension first, then second dimension", and the antenna ports are indexed in the subarray according to the principle of "first dimension first, then second dimension".

[0211] The hierarchical division described above is generally shown in Figure 8, using the following example: the base station antenna array is sized as eight antenna ports in the vertical direction (first spatial dimension) multiplied by four antenna ports in the horizontal direction (second spatial dimension), with the capability to perform transmissions from each antenna port in one of two orthogonal polarizations. Therefore, 64 digital base station ports are implemented on the antenna array considered with reference to Figure 8.

[0212] The left side of Figure 8 shows the first level (r=1) in the hierarchical division, where the antenna array is divided into... Each subarray has a size of [number] subarrays. , (That is, two antenna ports in the vertical direction multiplied by one antenna port in the horizontal direction), each of the subarrays will be the base station's The adjacent digital ports are combined. This results in (the transition indicated by the arrow) a virtual implementation of 32 combined CSI-RS ports in the same antenna array of the base station.

[0213] The middle section of Figure 8 shows the second level (r=2) in the hierarchical division, where the antenna array is divided. Each subarray has a size of [number] subarrays. , (That is, two antenna ports in the vertical direction multiplied by two antenna ports in the vertical direction), each of the subarrays will correspondingly increase the base station's... The digital ports are combined together. It can be seen that the subarray considered here largely consists of two subarrays corresponding to the first level in this hierarchical division. This results in (the transition indicated by the arrow) a virtual implementation of 16 combined CSI-RS ports in the base station antenna array.

[0214] Finally, the right side of Figure 8 shows the third level (r=3) in the partitioning hierarchy, where the base station's antenna array is partitioned. Each subarray has a size of [number] subarrays. , (That is, four antenna ports in the vertical direction multiplied by two antenna ports in the vertical direction), each of the subarrays will correspondingly increase the base station's... The digital ports are combined together. It can also be seen that the subarray considered here consists of two subarrays corresponding to the second level in the hierarchical division. This results in (the transition indicated by the arrow) a virtual implementation of eight combined CSI-RS ports in the base station antenna array.

[0215] For each of the partitioning options shown in Figure 8, the digital ports of the base station are indexed on the antenna array according to formula (4). It should be noted that this indexing order is consistent with... Figure 1 , Figure 2a The conventional index order shown is different. However, for each of the virtualizations shown in Figure 8, this conventional index order is used to index the combined ports.

[0216] Figure 9a The virtual partitioning options for the base station antenna array, corresponding to the lowest, first level discussed above, are shown in more detail.

[0217] Similar to Figure 8, Figure 9a The right side shows a base station antenna array with dimensions of four antenna ports in the vertical direction multiplied by four antenna ports in the horizontal direction. It has the capability to perform transmissions from each antenna port in one of two orthogonal polarizations, thus realizing 32 digital base station ports. Similar to the left side of Figure 8, the antenna array is divided into eight subarrays, each with dimensions of two antenna ports in the vertical direction multiplied by one antenna port in the horizontal direction. Each subarray combines two adjacent digital ports of the base station. This results in ( Figure 9a The left side of the base station antenna array is a virtual implementation of 16 combined CSI-RS ports.

[0218] Figure 9aThe illustration above the conversion arrow shows that combining two adjacent digital ports of a base station into a virtual port is essentially equivalent to combining the CSI-RS transmitted from these two digital ports into a single CSI-RS, where the weighting factor applied to each of the combined CSI-RS is equal to 1 (i.e., in this case, non-adaptive beamforming is essentially performed). The particular choice to combine adjacent digital ports in the vertical direction is primarily because (as a rule) the channel angular spread in the vertical plane is smaller than that in the horizontal plane; therefore, this combination based on non-adaptive averaging has a smaller negative impact on channel estimation quality. This is also illustrated in Figure 8 by prioritizing the vertical direction for port combination compared to the horizontal direction.

[0219] Figure 9b Showing the use of from Figure 9a The illustrated CSI-RS pattern is an exemplary CSI-RS pattern orthogonally multiplexed from the 32 digital ports of the base station antenna array. The illustrated CSI-RS pattern includes two CDM groups: the first group ( ) and the second group ( Each of these two CDM groups has a size of four REs at the frequency (i.e., Multiply by the four REs in time (i.e.) ), and these REs in Figure 9b The values ​​are marked with a light gray shading. The corresponding range of the base station digital port index {p} is also for... Figure 9b The first and second CDM groups are given. Throughout this specification, this CSI-RS pattern will be nominally referred to as the "original CSI-RS pattern".

[0220] Figure 9b The dark gray, thicker border line in the middle indicates the target Figure 9a The left side shows a CDM group formed by the virtualization of 16 combined CSI-RS ports. It can be seen that each of the formed CDM groups has the same size: four REs at the frequency (i.e., ) and the two REs in terms of time (reduced by half, i.e. Throughout this specification, corresponding to... Figure 9a A CSI-RS pattern that combines a set of ports and provides orthogonal multiplexing of 16 CSI-RSs will be nominally called a "reduced CSI-RS pattern". Other parameters of the time-frequency configuration of this reduced CSI-RS pattern remain unchanged from the original CSI-RS pattern; that is, it still includes two CDM groups with the same start carrier and start OFDM symbol.

[0221] from Figure 9b It can be seen that each CDM group of the simplified CSI-RS pattern is half of the corresponding CDM group of the original CSI-RS pattern, thus essentially forming its subgroup; the simplified CSI-RS pattern itself has a nested nature relative to the original CSI-RS pattern. Figure 9b The corresponding range of the index {p'} for the combined CSI-RS port for each of the CDM subgroups is also shown.

[0222] It should be noted here that each of the first and second CDM groups in the original CSI-RS pattern corresponds to Figure 6a , 6b The CDM group shown is from the CDM group family with iteration i=5, and the corresponding CDM group for the simplified CSI-RS pattern corresponds to the CDM group in the previous iteration i=4 of these families. That is, according to the preferred embodiment of the invention, the CDM group for forming the simplified CSI-RS pattern for the combined port is consistent with the system method of the invention described above. This preferred embodiment can also be extended to a greater number of virtual partitions (r>1), for example, the hierarchy of the combined port discussed above with reference to FIG8. In other words, for any hierarchy, the CDM group is defined such that the resource elements of the CDM group are part of the resource elements of the CDM group of the original CSI-RS pattern, that is, as mentioned above, the defined CDM group is a subgroup of the CDM group of the original CSI-RS pattern. In view of the above content regarding equations (2), (3) and Table 3, according to this preferred embodiment, the WH-OCC code subset is assigned to each subgroup of the CDM group respectively.

[0223] To effectively implement the port scaling proposed herein, this invention introduces an ordering of the WH-OCC code sequences applied in the CDM group, which is an alternative to the order in which they are applied, as indicated in 5G NR and when discussed in Table 2 above. The proposed alternative application ordering is defined by the following Equation 5.

[0224] [Formula 5]

[0225]

[0226] in It is the index of the WH-OCC code sequence in the CDM group according to the order in which the sorting is applied (in the entire text of this application, this sorting may be referred to in a non-limiting manner as the "first applied sorting"), It is the length of the WH-OCC code sequence, and It is a bitwise inversion permutation function that provides: to permutate the index The decimal representation is converted to a binary representation, the bit order in the binary representation is reversed, and the reversed binary representation is converted to a decimal representation of index s. The WH-OCC code sequence is assigned to the digital port in the CDM group according to the index {s} obtained according to formula (5) corresponding to the alternative application order (which may be referred to in a non-limiting manner as the "second application order" throughout this application).

[0227] function The provided conversion mechanism can be explained by the following formula:

[0228]

[0229] in It is an index The binary representation of It is the binary representation of the corresponding index s. These correspond to bits in binary representation. This is the number of bits in the binary representation of the index. Examples of applying this mechanism are given in Table 4 below.

[0230] [Table 4]

[0231]

[0232] By analogy with formula (1), when using the proposed method shown in formulas (5), (6) and Table 4, the index of the digital port on the base station antenna array can be represented by the following formula (7).

[0233] [Formula 7]

[0234]

[0235] Where p is the index of the digital port, It is an index of the OCC code sequence in the CDM group sorted according to the second application. It is the length of the OCC code sequence. It is the index of the CDM group in the CSI-RS pattern. This is the number of CDM groups in the CSI-RS pattern. By using formula (7) and with proper consideration of formula (5), it can be determined again from which digital port p to send which orthogonal code sequence of CSI-RS. Naturally, this index of the digital port is known in advance in the user equipment.

[0236] Consider the following Figure 9b The first CDM group of the original CSI-RS pattern shown ( As an example, according to an embodiment, the WH-OCC code sequences in the WH-OCC code set of the CDM group are initially sorted according to the first application sorting, and according to formula (1), the WH-OCC code sequences are sequentially assigned to digital ports, that is, the digital port with index p=0 is assigned the WH-OCC code sequence with index 0 in the WH-OCC code set, the digital port with index p=1 is assigned the WH-OCC code sequence with index 1 in the WH-OCC code set, and so on. In the case of the above-described alternative method according to the present invention, as described above, for the WH-OCC code sequence from the CDM group... Figure 9b The assignment of WH-OCC code sequences in the WH-OCC code set of the considered CDM group will be defined by the last row of Table 4. That is, the digital port with index p=0 is assigned the WH-OCC code sequence with index 0 in the WH-OCC code set, the digital port with index p=1 is assigned the WH-OCC code sequence with index 8 in the WH-OCC code set, the digital port with index p=2 is assigned the WH-OCC code sequence with index 4 in the WH-OCC code set, and so on.

[0237] Figures 10a-10d Possible options for indexing CDM groups in a CSI-RS pattern according to embodiments of the present invention are shown, particularly for use in formula (7), etc.

[0238] Specifically, according to the first embodiment of the considered embodiments ( Figure 10a The indexing of the CDM group is performed across the entire CSI-RS pattern according to the principle of "frequency first, time second". Figure 10b In the second embodiment shown, the CDM group again indexes the entire CSI-RS pattern according to the principle of "frequency first, then time". In the third embodiment ( Figure 10c In this context, the indexing of CDM groups within each PRB / slot is performed according to the principle of "frequency first, then time," while the transition between PRB / slots follows the principle of "time first, then frequency." Finally, according to... Figure 10d In the fourth embodiment shown, the CDM group is indexed within each PRB / slot according to the principle of "frequency first, then time," wherein subsequent transitions between PRBs / slots follow the principle of "frequency first, then time." In all... Figures 10a-10d middle, And accordingly, .

[0239] Here we should recall, referring to the above. Figure 2a , Figure 2bAccording to the publicly available information, in 5G NR, the only principle for indexing CDM groups along the CSI-RS pattern defined within a PRB and a time slot is "frequency first, then time" (i.e., first application sorting), and correspondingly, the only principle for indexing digital ports along the CSI-RS pattern is "within the CDM group first, then by frequency, and finally by time". Figures 10a-10d The embodiments shown clearly provide a more flexible indexing method.

[0240] Similar to the above reference Figures 6a to 6c The system method for forming a CDM group according to the present invention, as described, involves dividing the virtual hierarchy of the antenna array used into combined CSI-RS ports (including indexing options according to formula (4) and indexing options according to formula (7)) which is known in advance in (a plurality of) user equipments. According to one possible embodiment, this hierarchy division and indexing options may be preset in the user equipment or signaled to the user equipment in advance in a manner known to those skilled in the art. In another possible embodiment, the aforementioned control message sent from the base station to the user equipment prior to CSI-RS transmission may further include information regarding the hierarchy division, including indications of the indexing options.

[0241] It should be noted that although different levels of depth for the combined ports have been discussed above (see, for example, Figure 8 showing three levels), according to practical embodiments of the invention, a maximum of two levels are preferably used, i.e., r=1 (Figure 8, left side). Figure 9a ) and / or r=2 (middle part of Figure 8), thereby avoiding a decrease in channel estimation quality on the user equipment side.

[0242] Return to the basis Figure 9a , Figure 9b Considering the CSI-RS configuration, Table 5 below, in the context of the considered configuration, illustrates the reuse of ports in the hierarchy of combined CSI-RS ports based on their bit-reversed index according to the present invention.

[0243] The right-hand portion of Table 5 shows each index p for the digital port in the original CSI-RS pattern (see Table 5). Figure 9a The 16-length WH-OCC code sequence to be used for the digital port. It should be emphasized that the code sequence of digital port {p} is reordered in this part of the table according to the second application sort defined by index {s} (see formula (5), Table 4). Based on the above, the index s in the second column from the right in Table 5 shows the sequential number of the corresponding WH-OCC code sequence in the WH-OCC code set where the WH-OCC code sequences are sorted by default according to the first application sort (see Table 3).

[0244] [Table 5]

[0245]

[0246] The thicker boxes considered in Table 5 nominally contain portions of the WH-OCC code sequences in the WH-OCC code set of the CDM group of the original CSI-RS pattern. These portions are assigned in pairs to simplify the CSI-RS pattern (see Table 5). Figure 9a The CDM subgroups are reused. It can be seen that the assigned subsequences are identical in pairs—for example, the subsequences for the digital ports with indices 0 and 1 circled by ellipses—this is the result of the above reordering.

[0247] Similar to the right side, the left side of Table 5 shows simplified CSI-RS patterns (see...). Figure 9a Each index p' of the combined ports in the table is used for a WH-OCC code sequence of length 8 for that combined port. The code sequences of the combined CSI-RS ports {p'} are also sorted according to the second application sort defined by index {s'}. The entire reordered WH-OCC code subset of the CDM subgroup under discussion is also nominally outlined by a thicker box, similar to the right side of Table 5. It can be seen that each WH-OCC code sequence in the considered WH-OCC subset mathematically corresponds to a sequence with a weight factor equal to 1 ( Figure 9a In the middle part , The corresponding subsequence pairs in the WH-OCC code set of the CDM group of the original CSI-RS pattern are averaged—for example, the WH-OCC code sequence of the combined port with index p'=0 circled by the ellipse, as an example of the correspondence with the subsequence pairs circled by the ellipse on the right side of Table 5.

[0248] According to the method of the present invention, as referred to above Figure 7b Figure 8 Figures 9a to 10d As described in Tables 3 to 5, the invention according to the present invention enables the efficient formation of nested hierarchies of virtual combined CSI-RS ports based on the digital ports used and the corresponding CSI-RS patterns, thereby enabling the consistent formation of corresponding CDM subgroups and WH-OCC code subsets for each hierarchical level for both the base station and the user equipment. This method allows the user equipment to selectively perform channel estimation for a desired number of CSI-RS ports, i.e., for the combined ports corresponding to a specific level, and accordingly, to perform channel estimation based on the CDM subgroups and reordered WH-OCC code subsets corresponding to that level, which has appropriate quality and is transparent to the base station.

[0249] The following will refer to Figure 11The flowchart below describes the method 1100 for generating CSI-RS in a wireless communication system according to the present invention, which is preferably a next-generation communication system.

[0250] In step 1110, the base station (such as Figure 4 BS 402-A, BS 402-B, and BS 402-C (in which the preset number is used in the base station) The digital port defines the CSI-RS pattern. Step 1110 includes sub-steps 1111-1114 performed to define the CSI-RS pattern.

[0251] In sub-step 1111, the time domain is set. Groups of adjacent time slots and in the time domain A group of adjacent time slots. As described above, for next-generation communication systems with a large number of supported base station digital ports, according to a preferred embodiment of the present invention, and / or This will be greater than 1, thus providing the capacity required for the defined CSI-RS pattern. Specifically, in Figure 5a In the extended CSI-RS configuration shown, and ;exist Figure 5b In the extended CSI-RS pattern shown, ;exist Figure 5c In the extended CSI-RS configuration shown, Furthermore, according to the present invention, backward compatibility with 5G NR is supported, and and Both of these can be equal to 1.

[0252] In sub-step 1112, the quantity is set. The CDM group, wherein the setting includes setting the number in the frequency domain. CDM groups and the number set in the time domain CDM group, .

[0253] In sub-step 1113, a CDM group is defined, which includes setting the value of the CDM group to be equal to the specified value. The frequency magnitude of each subcarrier and equal to The time size of one OFDM symbol makes and It is being considered for reuse in this CDM group The settings are configured for the OCC of each CSI-RS. The lengths of the OCC code sequences are respectively... .

[0254] According to embodiments of the present invention, the above references Figures 6a to 6c The described systematic approach can be used to form CDM groups, especially with discontinuous arrangements of resource elements within the CDM group (see [link]). Figure 6b , Figure 6c ).

[0255] As described above, according to a preferred embodiment of the present invention, the OCC is an OCC based on Walsh-Hadamard Orthogonal Cover Code (WH-OCC). In this case, the length of the code sequence is... yes , where n is a non-negative integer. The WH-OCC code sequences are sorted by default according to the first application order described above and are sequentially assigned to the digital ports of the base station. The digital ports correspond to the CSI-RS to be multiplexed in the CDM group (see Table 4). As a result, a WH-OCC code set for the CDM group is formed, in which the WH-OCC code sequences are sorted according to the first application order.

[0256] In sub-step 1114, the following settings were made: The time-frequency arrangement of each CDM group, wherein setting the time-frequency arrangement includes setting the frequency domain CDM groups in The arrangement of each PRB within a group and in the time domain CDM groups in The arrangement within a group of time slots. See reference... Figures 5a to 5c The arrangement of CDM groups in the frequency domain includes targeting For each of the CDM groups, set the index of the starting subcarrier in the CSI-RS pattern. And setting the arrangement of CDM groups in the time domain includes targeting For each of the CDM groups, set the index of the starting OFDM symbol in the CSI-RS pattern. .

[0257] The generated CSI-RS pattern repeats on PRB groups. In the case of 5G NR (see Table 1), the repetition of the generated CSI-RS pattern can be specified by a predefined density ρ. Alternatively, the CSI-RS pattern can repeat on each sequential group of PRBs (ρ=1). An alternative is also provided where the CSI-RS pattern repeats only on PRB groups within those PRBs allocated in the base station for CSI-RS transmissions. ).

[0258] In step 1120, the base station sends information about the generated CSI-RS pattern to at least one user equipment (UE), such as according to Figure 4UE 401-1, UE 401-2, etc. Specifically, the base station can send control information including at least the following indications through at least one of DCI, MAC signaling, and RRC signaling: , , , , , , Based on the above, if the system method according to the present invention is applied, the transmitted control messages may also include intervals. At least some of the instructions (see Figures 6a to 6c (Discussion). As mentioned above, the WH-OCC code set of the CDM group of the generated CSI-RS pattern, as well as the first application order, are pre-available in the user equipment.

[0259] Based on the above, the base station can be configured to simultaneously transmit CSI-RS on the CC set (see [link]). Figure 7a , Figure 7b In this case, method 1100 will be executed for each CC in the CC set.

[0260] The following will refer to Figure 12 The flowchart describes a method 1200 for generating CSI-RS according to a more specific embodiment of the present invention, wherein port hierarchical scaling is used. In this method, in the base station (such as according to...) Figure 4 (BS 402-A, BS402-B, BS 402-C), preset quantity The digital ports used are implemented in the antenna array of the base station, wherein a hierarchy of combined ports is used in the base station, wherein each combined port in the corresponding hierarchy combines a corresponding predefined number of digital ports of the base station (see Figure 8 above). Figure 9a , Figure 9b (Discussion).

[0261] In step 1210, the base station defines a CSI-RS pattern. Step 1210 includes sub-steps 1211-1215 performed to define the CSI-RS pattern.

[0262] In sub-step 1211, similar to sub-step 1111, the frequency domain is set... Groups of adjacent PRBs and in the time domain A group of adjacent time slots. In sub-step 1212, similar to sub-step 1112, the number is set. The CDM group, wherein the setting includes setting the number in the frequency domain. CDM groups and the number set in the time domain CDM group, .

[0263] In sub-step 1213, a CDM group is defined, where, similar to sub-step 1113, defining the CDM group includes setting an equal value for the CDM group. The frequency magnitude of each subcarrier and equal to The time size of one OFDM symbol makes According to the considered embodiment, it is to be used in the CDM group for reuse. The OCC of each CSI-RS is a length of The WH-OCC code sequence of the CDM group, wherein, for the CDM group, the WH-OCC code sequence is initially assigned to the digital port according to the first application sorting, thereby forming the WH-OCC code set of the CDM group in which the WH-OCC code sequence is sorted according to the first application sorting.

[0264] In sub-step 1214, similar to sub-step 1114, set... The time-frequency arrangement of each CDM group, wherein setting the time-frequency arrangement includes setting the frequency domain CDM groups in The arrangement of each PRB within a group and in the time domain CDM groups in The arrangement within a group of time slots.

[0265] In sub-step 1215, a CDM subgroup is defined for each level. The resource elements of the CDM subgroup are formed from a portion of the resource elements of the CDM group defined in sub-step 1213. Furthermore, a corresponding WH-OCC code subset is defined; the WH-OCC code sequence of the WH-OCC code subset is initially assigned to the combination port according to the first application order. Based on the above, the defined CDM subgroup can correspond to a CDM group of a CDM group family according to the system method.

[0266] Similar to method 1100, the CSI-RS pattern defined in step 1210 is repeated on the PRB group.

[0267] In step 1220, the WH-OCC code sequence in the WH-OCC code set of the CSI-RS pattern of the CDM group is reordered in the base station according to the second application sorting, which is defined by applying bit reversal permutation to the corresponding indexes of the WH-OCC code sequence of the CDM group as described above with reference to formulas (5), (6) and Table 4. These indices correspond to the first application sorting.

[0268] The specific details of the implementation schemes for sub-steps 1215 and 1220 are shown in Figure 8 above. Figures 9a to 10d As provided in the explanations in Tables 3 to 5.

[0269] Specifically, this hierarchy is formed by dividing the base station's antenna array into sub-arrays (see Figure 8). Figure 9a As mentioned above, in the r-th level ( The antenna array is divided into There are three identical subarrays, each with a size of [size in the first spatial dimension]. Each antenna port multiplied by the second spatial dimension One antenna port ( , , Each subarray of level r consists of two subarrays of level (r-1), such that... or The size of the first-level (r=1) subarray is , As mentioned above, the r-th level ( Each subarray of ) represents a combined port, which will The digital ports of each base station are combined (see Figure 8). For the corresponding level, the index of the digital port on the base station antenna array can be defined according to formula (4). Preferably, at most two levels are involved in the considered levels, i.e., r=1 (see Figure 8). Figure 9a ) and / or r=2. Figures 10a to 10d One of the options shown can be used to index the CDM group in the CSI-RS pattern.

[0270] In step 1230, similar to step 1120, the base station preferably sends information about the CSI-RS pattern to at least one user equipment in the DCI / MAC / RRC control message, such as according to Figure 4 UE 401-1, UE 401-2, etc. In one implementation, the control message may include information about the port level, including the relevant index options. In another implementation, this information may be predefined in the user equipment or pre-signaled to the user equipment.

[0271] In step 1240, the user equipment performs channel estimation for the combined port corresponding to the specific level, based on the CDM subgroup and WH-OCC code subset corresponding to that level, wherein the WH-OCC code subset is reordered according to the second application sorting (see Table 5). As described above, the channel estimation is performed by the user equipment to generate the CSI. More specifically, in step 1240, the user equipment may decide to perform channel estimation for the combined port corresponding to the r-th level. (See) Figure 7a , Figure 7b(See the discussion in Figure 8), and the user equipment performs channel estimation based on the CDM subgroup corresponding to the r-th level and the reordered WH-OCC code subset.

[0272] In the case of method 1100, the base station can be configured to transmit CSI-RS simultaneously on a set of component carriers, and in this case, method 1200 will also be performed for each component carrier in the set.

[0273] The mechanism for selecting a specific tier of combined CSI-RS ports for use on the user equipment side can rely on UE capabilities, which are signaled to the base station by the user equipment after the user equipment connects to the base station. For example, if the user equipment uses two or more component carriers for DL ​​reception, and the UE capabilities in generating CSI do not allow processing CSI-RS and calculating CSI using the maximum number of CSI-RS ports on all component carriers, then the base station must configure the user equipment to perform CSI-RS estimation using a smaller number of ports on each carrier (i.e., r>1).

[0274] As can be seen from the above, the CSI-RS configuration according to the present invention provides support for the number of digital ports to meet the design requirements of next-generation communication systems, while providing the ability to systematically form CDM groups and arrange them in time and frequency on PRB / time slot groups, with greater flexibility in allocating time and frequency resources to each CDM group, and the ability to nest and scale CSI-RS ports in a manner transparent to base stations and user equipment.

[0275] It should also be understood that the exemplary embodiments shown are merely preferred, but not the only possible, implementations of the invention, and that the various aspects of the invention disclosed above can be implemented individually or in combination. More specifically, the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for generating a Channel State Information Reference Signal (CSI-RS) in a wireless communication system, performed by a base station (BS), the method comprising: For the preset number N in the base station p The digital port used defines a CSI-RS pattern consisting of resource elements (REs), wherein each resource element is defined by a subcarrier in the frequency domain and by an orthogonal frequency division multiplexing (OFDM) symbol in the time domain, wherein the definition includes, for the CSI-RS pattern: Set the frequency domain A group of adjacent physical resource blocks (PRBs) and in the time domain A group of adjacent time slots TTI, among which , It is a natural number, and , At least one of them is greater than 1; Set quantity The code division multiplexing (CDM) group, where the number is set. The CDM group includes a number set in the frequency domain. The CDM group and the number set in the time domain CDM group, ,in , It is a natural number; Define a CDM group, wherein defining a CDM group includes setting the CDM group to equal to The frequency magnitude of each subcarrier and equal to The time size of one OFDM symbol makes ,in and It is being considered for use in reusing the CDM group. This is set in the case of an orthogonal overlay code (OCC) of CSI-RS, wherein the length of the code sequence of the OCC is ;as well as set up The time-frequency arrangement of the CDM groups, wherein setting the time-frequency arrangement includes setting the frequency domain... CDM groups in The arrangement within a group of PRBs and the settings in the time domain CDM groups in The arrangement within a group of time slots, The CSI-RS pattern is repeated on the PRB group.

2. The method according to claim 1, wherein: Setting up the CDM group in the frequency domain includes targeting Each of the CDM groups sets the index k of the starting subcarrier in the CSI-RS pattern, and Setting up the CDM group in the time domain includes targeting For each of the CDM groups, set the index of the starting OFDM symbol in the CSI-RS pattern. l ; The CSI-RS pattern repeats at a preset density. Executed, of which The CSI-RS pattern is repeated on each sequential group of the PRB. ),or The CSI-RS pattern repeats only on the PRB group among those PRBs allocated in the base station for CSI-RS transmissions. ).

3. The method of claim 2, further comprising sending a message from the base station to at least one user equipment (UE) in the wireless communication system, the message including at least the following indication: , , , , , ,index The message is sent via at least one of DCI, MAC signaling, or RRC signaling.

4. The method according to claim 3, wherein the OCC is an OCC based on the Walsh-Hadamard orthogonal covering code WH-OCC, wherein Equal to 2 n ,in n It is a non-negative integer, wherein the WH-OCC code sequence is initially assigned to a digital port according to a first application order predefined in the base station, the digital port corresponding to the CSI-RS to be multiplexed in the CDM group, thereby forming the WH-OCC code set of the CDM group, wherein the WH-OCC code sequence is ordered in the WH-OCC code set according to the first application order. The WH-OCC code set is available in the user equipment, and the first application order is preset in the user equipment or is transmitted to the user equipment in advance via signaling.

5. The method of claim 3, wherein defining the CDM group comprises: implement: The i-th CDM group in the family is defined by replicating the (i-1)-th CDM group in the family in terms of frequency or time, where i is a natural number, i>1, where, If the replication is performed at a frequency, then The two (i-1)th CDM groups comprised of the i-th CDM group of the family are... Separated by a preset interval of subcarriers, among which It is a non-negative integer, or If the replication is performed in time, then The two (i-1)th CDM groups comprised of the i-th CDM group of the family are... Separated by a preset interval of OFDM symbols, where It is a non-negative integer. until equal ,and equal .

6. The method according to claim 5, wherein: The original CDM group of the family is a CDM group consisting of a resource element ( , ),in and The value is 0, 1, or 2. >2, of which ,or The original CDM group of the family is a CDM group consisting of more than one resource element, wherein and The value is 0, 1, or 2.

7. The method of claim 6, wherein the message further includes an interval. and / or interval Indicates at least some intervals.

8. A base station (BS) for generating a channel state information reference signal (CSI-RS) in a wireless communication system, the BS comprising: transceiver; as well as At least one processor, the processor being configured to handle a preset number N in the base station p The digital port used defines a CSI-RS pattern consisting of resource elements (REs), where each resource element is defined by a subcarrier in the frequency domain and by orthogonal frequency division multiplexing (OFDM) symbols in the time domain. The at least one processor is further configured for the CSI-RS pattern: Set the frequency domain A group of adjacent physical resource blocks (PRBs) and in the time domain A group of adjacent time slots TTI, among which , It is a natural number, and , At least one of them is greater than 1; Set quantity The code division multiplexing (CDM) group, where the number is set. The CDM group includes a number set in the frequency domain. The CDM group and the number set in the time domain CDM group, ,in , It is a natural number; Define a CDM group, wherein defining a CDM group includes setting the CDM group to equal to The frequency magnitude of each subcarrier and equal to The time size of one OFDM symbol makes ,in and It is being considered for use in reusing the CDM group. This is set in the case of an orthogonal overlay code (OCC) of CSI-RS, wherein the length of the code sequence of the OCC is ;as well as set up The time-frequency arrangement of the CDM groups, wherein setting the time-frequency arrangement includes setting the frequency domain... CDM groups in The arrangement within a group of PRBs and the settings in the time domain CDM groups in The arrangement within a group of time slots, The CSI-RS pattern is repeated on the PRB group.

9. The BS according to claim 8, wherein: Setting up the CDM group in the frequency domain includes targeting Each of the CDM groups sets the index k of the starting subcarrier in the CSI-RS pattern, and Setting up the CDM group in the time domain includes targeting For each of the CDM groups, set the index of the starting OFDM symbol in the CSI-RS pattern. l ; The CSI-RS pattern repeats at a preset density. Executed, of which The CSI-RS pattern is repeated on each sequential group of the PRB. ),or The CSI-RS pattern repeats only on the PRB group among those PRBs allocated in the base station for CSI-RS transmissions. ).

10. The BS of claim 9, wherein the at least one processor is further configured to: A message is sent from the base station to at least one user equipment (UE) in the wireless communication system, the message including at least the following indications: , , , , , ,index The message is sent via at least one of DCI, MAC signaling, or RRC signaling.

11. The BS of claim 10, wherein the OCC is an OCC based on the Walsh-Hadamard orthogonal covering code WH-OCC, wherein Equal to 2 n ,in n It is a non-negative integer, wherein the WH-OCC code sequence is initially assigned to a digital port according to a first application order predefined in the base station, the digital port corresponding to the CSI-RS to be multiplexed in the CDM group, thereby forming the WH-OCC code set of the CDM group, wherein the WH-OCC code sequence is ordered in the WH-OCC code set according to the first application order. The WH-OCC code set is available in the user equipment, and the first application order is preset in the user equipment or is transmitted to the user equipment in advance via signaling.

12. The BS of claim 10, wherein the at least one processor is further configured to: The i-th CDM group in the family is defined by replicating the (i-1)-th CDM group in the family in terms of frequency or time, where i is a natural number, i>1, where, If the replication is performed at a frequency, then The two (i-1)th CDM groups comprised of the i-th CDM group of the family are... Separated by a preset interval of subcarriers, among which It is a non-negative integer, or If the replication is performed in time, then The two (i-1)th CDM groups comprised of the i-th CDM group of the family are... Separated by a preset interval of OFDM symbols, where It is a non-negative integer. until equal ,and equal .

13. The BS according to claim 12, wherein: The original CDM group of the family is a CDM group consisting of a resource element ( , ),in and The value is 0, 1, or 2. >2, of which ,or The original CDM group of the family is a CDM group consisting of more than one resource element, wherein and The value is 0, 1, or 2.

14. The BS of claim 13, wherein the message further includes an interval. and / or interval Indicates at least some intervals.

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