CN110495124B

CN110495124B - Method for allocating CSI-RS for beam management

Info

Publication number: CN110495124B
Application number: CN201880020001.9A
Authority: CN
Inventors: 金载原; 柳炫圭; 李南贞
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2017-03-23
Filing date: 2018-03-23
Publication date: 2023-04-04
Anticipated expiration: 2038-03-23
Also published as: KR20180108375A; CN110495124A; KR102354588B1

Abstract

The present disclosure relates to a communication technology for fusing a fifth generation (5G) communication system supporting a higher data transmission rate than a fourth generation (4G) system with an internet of things (IoT) technology, and a system thereof. The present disclosure may be applied to smart services (e.g., smart homes, smart buildings, smart cities, smart cars or connected cars, health care, digital education, retail business, security and security related services, etc.) based on 5G communication technology and IoT related technology. The present disclosure relates to a method and apparatus for searching for or determining information about beams that a UE or a base station can use for signal transmission and reception in a mobile communication system.

Description

Method for allocating CSI-RS for beam management

Technical Field

The present disclosure relates to a method and apparatus for searching for or determining information about beams that a User Equipment (UE) or a base station can use for signal transmission and reception in a mobile communication system.

Background

To meet the ever-increasing demand for radio data services since the commercialization of fourth generation (4G) communication systems, work has been conducted to develop improved fifth generation (5G) or pre-5G (pre-5G) communication systems. Therefore, the 5G communication system or the pre-5G communication system is referred to as a super 4G network communication system or a post Long Term Evolution (LTE) system. In order to achieve a high data transmission rate, it is considered to implement a 5G communication system in a very high frequency (millimeter wave) band, such as a 60GHz band, for example. In order to mitigate path loss of radio waves in a very high frequency band and increase a transmission distance of radio waves, in a 5G communication system, beam forming, massive multiple input multiple output (massive MIMO), full-dimensional MIMO (FD-MIMO), array antenna, analog beam forming, and massive antenna techniques have been discussed. In addition, in order to improve the network of the system, in a 5G communication system, techniques such as evolved small cell, advanced small cell, cloud radio access network (cloud RAN), ultra-dense network, device-to-device (D2D) communication, wireless backhaul, mobile network (moving network), cooperative communication, coordinated multipoint (CoMP), and reception interference cancellation have been developed. In addition to this, in the 5G system, hybrid Frequency Shift Keying (FSK) and Quadrature Amplitude Modulation (QAM) modulation (FQAM) and Sliding Window Superposition Coding (SWSC) have been developed as Advanced Coding Modulation (ACM) schemes, and filter bank multi-carrier (FBMC), non-orthogonal multiple access (NOMA), sparse Code Multiple Access (SCMA), and the like as advanced access technologies.

Meanwhile, the internet evolved from a human-centric connected network through which humans generated and consumed information to an internet of things (IoT) network that transmits/receives information and processes information between distributed components such as objects. Internet of everything (IoE) technology has also emerged, in which a big data processing technology or the like is combined with an IoT technology through connection with a cloud server or the like. To implement IoT, technical elements such as sensing technology, wired and wireless communication and network infrastructure, service interface technology, and security technology are required. Recently, technologies for connecting between objects, such as sensor networks, machine-to-machine (M2M), and Machine Type Communication (MTC), have been studied. In an IoT environment, intelligent Internet Technology (IT) services may be provided that create new value in human life by collecting and analyzing data generated in connected objects. By fusing and integrating existing Information Technology (IT) with various industries, ioT may be applied in various fields, such as smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, healthcare, smart appliances, and advanced medical services.

Accordingly, various attempts have been made to apply the 5G communication system to the IoT network. For example, 5G communication technologies such as sensor networks, M2M, and MTC have been implemented by technologies such as beamforming, MIMO, and array antennas. The application of cloud RAN as the big data processing technology described above can also be seen as an example of merging 5G communication technology with IoT technology.

According to recent developments of LTE and LTE-advanced, a method of acquiring information about beams that a User Equipment (UE) or a base station may use for signal transmission and reception in a mobile communication system may be required.

The above information is presented as background information only to aid in understanding the present disclosure. No determination is made, nor is a statement made, as to whether any of the above information is applicable as prior art to the present disclosure.

Disclosure of Invention

Technical problem

The present invention provides a search procedure for discovering and determining information about beams that a UE or a base station can use for signal transmission and reception. Then, the base station and the UE exchange detected beam information with each other, and a procedure of sharing information on beams to be used for subsequent transmission and reception is proposed.

Solution to the problem

Various aspects of the present disclosure are to address at least the above problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the present disclosure is to provide a search procedure for searching for and determining information about beams that a User Equipment (UE) or a base station can use for signal transmission and reception. The present disclosure provides a process of exchanging searched beam information and sharing information on beams to be used for subsequent transmission and reception between a base station and a UE.

Aspects of the present disclosure are not limited to the above aspects. For example, other aspects not mentioned can be easily understood by those skilled in the art to which the present disclosure pertains from the following description.

According to an aspect of the present disclosure, there is provided a method of beam management by a UE. The method comprises the following steps: receiving channel state information reference signal (CSI-RS) resource information for beam management from a base station, the CSI-RS resource information including a repetition indicator indicating whether a set of CSI-RS resources is repeated in a time domain; and transmitting a beam report of the CSI-RS resource set based on the CSI-RS resource information to the base station.

According to an embodiment of the present disclosure, the CSI-RS resource information includes at least one of a Synchronization Sequence (SS) block index having a quasi-co-location (QCL) relationship with the CSI-RS resource set, resource allocation information of the CSI-RS resource set, and a transmission period of the CSI-RS resource set.

According to an embodiment of the present disclosure, when the repetition indicator is set to a first value, the set of CSI-RS resources in a symbol is repeated over N symbols, and, when the repetition indicator is set to a second value, the set of CSI-RS resources is located in a specified symbol.

According to an embodiment of the present disclosure, the method further includes selecting a beam to receive the set of CSI-RS resources when the repetition indicator is set to a first value.

According to an embodiment of the present disclosure, the CSI-RS resource information is received via one of a Master Information Block (MIB), a System Information Block (SIB), and a Radio Resource Control (RRC) message.

According to another aspect of the present disclosure, a method of beam management by a base station is provided. The method comprises the following steps: transmitting, to a UE, CSI-RS resource information for beam management, the CSI-RS resource information including a repetition indicator indicating whether a set of CSI-RS resources is repeated in a time domain, and receiving, from the UE, a beam report of the set of CSI-RS resources based on the CSI-RS resource information.

According to an embodiment of the present disclosure, the CSI-RS resource information includes at least one of an SS block index having a QCL relationship with a CSI-RS resource set, resource allocation information of the CSI-RS resource set, and a transmission period of the CSI-RS resource set.

According to an embodiment of the present disclosure, the set of CSI-RS resources in a symbol is repeated over N symbols when the repetition indicator is set to a first value, and the set of CSI-RS resources is located in a specified symbol when the repetition indicator is set to a second value.

According to an embodiment of the disclosure, a beam to receive the set of CSI-RS resources is selected when the repetition indicator is set to the first value.

According to an embodiment of the present disclosure, the CSI-RS resource information is transmitted via one of MIB, SIB, and RRC messages.

According to another aspect of the present disclosure, there is provided a UE for performing beam management. The UE includes: a transceiver; and at least one processor coupled with the transceiver and configured to control to: receiving CSI-RS resource information for beam management from a base station, the CSI-RS resource information including a repetition indicator indicating whether a set of CSI-RS resources is repeated in a time domain, and transmitting a beam report of the set of CSI-RS resources based on the CSI-RS resource information to the base station.

According to another aspect of the present disclosure, there is provided a base station for performing beam management. The base station includes: a transceiver; and at least one processor coupled with the transceiver and configured to control to: transmitting, to a UE, CSI-RS resource information for beam management, the CSI-RS resource information including a repetition indicator indicating whether a set of CSI-RS resources is repeated in a time domain, and receiving, from the UE, a beam report of the set of CSI-RS resources based on the CSI-RS resource information.

According to an embodiment of the present disclosure, it is assumed that the present disclosure is based on a two-layer beam configuration. The first layer beam referred to in this disclosure refers to a base station beam used for transmitting an SS block. The first layer beam may be used for control and data transmission until the search for the second layer beam is completed. Hereinafter, a beam search and setup procedure for the first layer will be referred to as a P1 beam management (P2 BM) operation. The second layer beam referred to in this disclosure refers to a base station beam used for control and data transmission. Hereinafter, a beam search and setup procedure for the second layer will be referred to as a P2 beam management (P2 BM) operation. The present disclosure proposes a method of operating a base station/UE to support P1 and P2 procedures and a method of allocating CSI-RS for beam search.

Other aspects, advantages, and salient features of the disclosure will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses various embodiments of the disclosure.

Advantageous effects of the invention

The present invention provides a method for determining information on beams that a UE or a base station can use for signal transmission and reception and exchanging the determined beam information between the UE and the base station.

Drawings

The above and other aspects, features and advantages of certain embodiments of the present disclosure will become more apparent from the following description, which is to be read in connection with the accompanying drawings, wherein:

FIG. 1 is a diagram illustrating the overall operation of an embodiment according to the present disclosure;

fig. 2A and 2B are diagrams illustrating a first embodiment (when a cell-specific Reference Signal (RS) is not allocated) for performing a beam search and setting procedure according to various embodiments of the present disclosure;

fig. 3A and 3B are diagrams illustrating a second embodiment (when a cell-specific RS is allocated) for performing a beam search and setting procedure according to various embodiments of the present disclosure;

fig. 4 is a diagram illustrating a quasi co-location (QCL) relationship between a Synchronization Sequence (SS) block and a first channel state information RS (CSI-RS) (= cell-specific RS) according to an embodiment of the present disclosure;

fig. 5 is a diagram illustrating an embodiment of a method of configuring a first CSI-RS (= cell-specific RS) according to an embodiment of the present disclosure;

fig. 6 is a diagram illustrating an embodiment of a method of configuring a first CSI-RS (= cell-specific RS) (Tracking RS support) according to an embodiment of the present disclosure;

fig. 7A and 7B are diagrams illustrating embodiments of methods of configuring a first CSI-RS (supporting two antenna ports) (tracking RS support) according to various embodiments of the present disclosure;

fig. 8 is a diagram illustrating a configuration of a base station according to an embodiment of the present disclosure;

fig. 9 is a diagram illustrating a configuration of a terminal according to an embodiment of the present disclosure;

fig. 10 is a diagram illustrating a Resource Element (RE) mapping pattern of CSI-RS resources according to an embodiment of the present disclosure;

11A, 11B, and 11C are diagrams illustrating processes of transmitting SS blocks and sets of CSI-RS resources according to various embodiments of the present disclosure;

fig. 12 is a diagram illustrating an embodiment of an RE mapping pattern of CSI-RS according to an embodiment of the present disclosure;

fig. 13 is a diagram illustrating an embodiment of an RE mapping pattern of CSI-RS according to an embodiment of the present disclosure;

fig. 14 is a diagram illustrating an embodiment of an RE mapping pattern of CSI-RS according to an embodiment of the present disclosure;

fig. 15 is a diagram illustrating mapping of one CSI-RS every two res according to an embodiment of the present disclosure;

fig. 16 is a diagram illustrating an embodiment that may be used for P1 beam management (P1 BM) only without tracking RS support according to an embodiment of the present disclosure;

fig. 17 is a diagram illustrating an embodiment that may be used for P1BM only without tracking RS support according to an embodiment of the present disclosure;

FIG. 18 is a diagram illustrating an embodiment supporting time domain repetition according to an embodiment of the present disclosure;

fig. 19 is a diagram illustrating an RE mapping pattern of CSI-RS according to an embodiment of the present disclosure, illustrating a case where Code Division Multiplexing (CDM) is not applied between resources;

fig. 20 is a diagram illustrating an RE mapping pattern of CSI-RS according to an embodiment of the present disclosure, illustrating a case where CDM is applied between resources;

fig. 21 is a diagram illustrating an RE mapping pattern of CSI-RS according to an embodiment of the present disclosure, and illustrates a case where CDM is not applied between resources;

fig. 22 is a diagram illustrating an embodiment of defining several sets of resources in one Orthogonal Frequency Division Multiplexing (OFDM) symbol in accordance with an embodiment of the present disclosure;

fig. 23 is a diagram illustrating an embodiment of defining several resource sets in one OFDM symbol according to an embodiment of the present disclosure;

fig. 24, 25, 26, 27, 28, and 29 are diagrams illustrating resource indexes and resource set indexes of CSI-RSs transmitted in one slot, according to various embodiments of the present disclosure;

FIG. 30 is a diagram illustrating a process of performing resource setup with indexes of S1, S2, …, SN according to an embodiment of the present disclosure;

fig. 31 is a diagram illustrating QCL information between K1 CSI-RS resources for P1BM and K2 resources for P2 BM according to an embodiment of the present disclosure;

fig. 32 is a diagram illustrating CSI-RS resource setting between a base station and a terminal according to an embodiment of the present disclosure;

fig. 33 is a diagram illustrating a case where K CSI-RS resources (or port groups) are allocated to one OFDM symbol according to an embodiment of the present disclosure;

fig. 34 is a diagram illustrating a case where one resource or port group is mapped to NP × L res according to an embodiment of the present disclosure;

fig. 35 is a diagram illustrating an embodiment of a case where two resource groups are set in one OFDM symbol according to an embodiment of the present disclosure; and

fig. 36 is a diagram illustrating a case where a sub-time unit OFDM symbol of L =4 is generated within one OFDM symbol interval according to an embodiment of the present disclosure.

In the drawings, it should be noted that the same reference numerals are used to depict the same or similar elements, features and structures.

Detailed Description

The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of various embodiments of the disclosure as defined by the claims and their equivalents. It includes various specific details to aid understanding but these are to be considered exemplary only. Accordingly, those of ordinary skill in the art will appreciate that various changes and modifications may be made to the various embodiments described herein without departing from the scope and spirit of the present disclosure. Further, descriptions of well-known functions and constructions may be omitted for clarity and conciseness.

The terms and words used in the following description and claims are not limited to the bibliographic meanings, but are used only by the inventors to enable a clear and consistent understanding of the disclosure. Accordingly, it should be apparent to those skilled in the art that the following descriptions of the various embodiments of the present disclosure are provided for illustration only and not for the purpose of limiting the disclosure as defined by the appended claims and their equivalents.

It should be understood that the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a component surface" includes reference to one or more such surfaces.

The term "substantially" means that the recited characteristic, parameter, or value need not be exactly achieved, but that there may be deviations or variations in the amount that do not preclude the effect that the characteristic was intended to provide, including tolerances, measurement error, measurement accuracy limitations, and other factors known to those of skill in the art.

Various advantages and features of the present disclosure and methods of accomplishing the same will become apparent from the following detailed description of the embodiments with reference to the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed herein, but will be embodied in various forms. The embodiments have completed the disclosure of the present disclosure and are provided to enable those skilled in the art to easily understand the scope of the present disclosure. Accordingly, the disclosure is to be limited only by the scope of the following claims. Like reference numerals refer to like elements throughout the specification.

The first embodiment: method for operating P3 program based on Synchronous Sequence (SS) block index report

The present disclosure assumes a two-layer beam configuration as a basis. The first layer beam referred to in this disclosure refers to a base station beam used for transmitting an SS block. The first layer beam may be used for control and data transmission until the search for the second layer beam is completed. Hereinafter, a procedure of searching and setting a beam for the first layer will be referred to as a P1 beam management (P1 BM) operation. The second layer beam referred to in the present disclosure refers to a base station beam used for control and data transmission. Hereinafter, a beam search and setup procedure for the second layer will be referred to as a P2 beam management (P2 BM) operation.

Meanwhile, a P3 beam management (P3 BM) operation referred to in the present disclosure refers to a process of supporting a search for a terminal beam.

Fig. 1 is a diagram illustrating the overall operation of an embodiment according to the present disclosure.

Referring to fig. 1, at the time of initial access, a base station 100 and a User Equipment (UE) 110 complete search and setting of beams that can be used for signal transmission and reception between the base station 100 and the UE 110. The beam corresponds to a beam belonging to a first layer. When an additional beam setting procedure is performed during data transmission after the initial access, the configuration of the beam at the initial access may be updated to the setting of the beam belonging to the second layer.

In this case, searching for a beam means a process of searching for and determining information about a beam that the UE 110 or the base station 100 can use for signal transmission and reception. Meanwhile, setting a beam refers to a process of exchanging searched beam information between the base station 110 and the UE 110 and sharing information about a beam to be used for subsequent transmission and reception.

The present disclosure provides two representative embodiments for performing a beam search and setup procedure. On the other hand, depending on whether a subsequent cell specific Reference Signal (RS) is allocated, it may be determined whether to operate according to the first embodiment or the second embodiment. For example, when the cell-specific RS is not allocated, the base station/terminal may be operated as in the first embodiment. Meanwhile, when the cell-specific RS is not allocated, the base station/terminal can be operated as in the second embodiment. Meanwhile, whether to operate according to the first embodiment or the second embodiment may be determined depending on the determination of the base station. For example, the base station may inform the terminal whether to perform setting of the BM operation based on either of the two embodiments.

Fig. 2A and 2B are diagrams illustrating a first embodiment (when a cell-specific RS is not allocated) for performing a beam search and setting procedure according to various embodiments of the present disclosure.

Referring to fig. 2A, at this time, the UE 210 receives a synchronization (Synch) signal composed of SS blocks for executing the P1 program from the base station 200. The UE 210 determines a preferred best SS block index based on the received synchronization signal and feeds back the determined best SS block index to the base station 200. At this time, the UE 210 may select an L value, which is a value corresponding to the number of terminal reception beams for receiving the best SS block index. The number of the best SS block indexes to be fed back to the base station 200 may be one or more, and the base station may set the number of the best indexes to be fed back in the terminal.

Referring to fig. 2B, in the subsequent P2 and P3 procedures, beam search is performed by allocating UE-specific RSs. The base station 200 selects K base station beams to be used for P2 and P3 procedures based on the best SS block index information fed back by the UE 210. Then, a UE-specific RS consisting of K base station beams is allocated so that the UE 210 can select the best N base station beams. At this time, the UE-specific RS may be repeatedly transmitted L times on the timing based on the number L of terminal beams. In order to efficiently perform such repetitive transmission, the UE-specific RS may have an Orthogonal Frequency Division Multiplexing (OFDM) symbol length shorter than an OFDM symbol length used for general data transmission. The OFDM symbol length having a short length is referred to as a sub time unit in fig. 2A and 2B.

The UE 210 receives each set of channel state information RS (CSI-RS) resources using L terminal beams in each sub-time unit. The UE 210 selects N resource sets, selects a corresponding UE beam for each selected resource set, and generates a corresponding Precoding Matrix Indicator (PMI)/Rank Indicator (RI)/Channel Quality Indicator (CQI) report for each selected resource set. Then, the UE 210 reports a Multiple Input Multiple Output (MIMO) report (N resource indexes, a UE beam set index corresponding to each resource, a PMI/RI/CQI corresponding to each resource) to the base station 200.

The second embodiment: method of operating P3 program based on P-CSI-RS having quasi-co-location (QCL) relationship with SS block

Fig. 3A and 3B are diagrams illustrating a second embodiment (when a cell-specific RS is allocated) for performing a beam search and setting procedure according to various embodiments of the present disclosure.

Referring to fig. 3A and 3B, the base station 300 provides the UE 310 with Rx (receive) beam QCL relationship information between a synchronization signal and a cell-specific RS, and transmits the synchronization signal (composed of M SS blocks) to the UE 310. The UE 310 measures the strength of the received signal strength of each UE and selects L corresponding terminal beams for each SS block index. The base station 300 transmits a cell-specific RS (consisting of M resource sets) to perform the P1 procedure.

The UE 310 receives a resource set having a QCL relationship using a cell-specific RS in one of L terminal beams, performs measurement on a base station beam through reception of the cell-specific RS, and performs BM reporting at the request of the base station 300. When the base station 300 requests the BM report to the UE 310, the base station 300 may indicate the following K value to the UE 310. At this time, the BM report may include information indicating K base station beam indexes and received signal strength information of K beams. In addition, the terminal may also report UE beam set index information together for the K base station beams.

For K' beams reported to the base station 300 with the same UE beam set index among the K base station beams, the base station 300 assumes that the UE 310 can receive signals using the same terminal beam. The base station 300 receiving the BM report including the UE beam set index may simultaneously transmit and receive signals to and from the UE 310 using beams corresponding to the base station beam IDs having the same set index. Alternatively, in order to transmit and receive signals to and from the terminal, the base station may alternately use base station beams corresponding to base station beam IDs having the same set index without notifying the terminal in advance. The cell-specific RS for P1BM operation may be replaced with UE-specific RS for P1BM, depending on the base station and set determination.

The third embodiment: CSI-RS resource setting method for beam management

A CSI-RS resource setting method according to the present disclosure will be described below. The present disclosure includes three types of CSI-RS resource setting methods, referred to as "P1 BM and tracking RS", "P2 and P3 BM", and "P2 BM and MIMO CSI", respectively.

The first type of CSI-RS denotes a cell-specific RS involved in the beam search and setup method. The first type of CSI-RS may be used for P1BM and tracking RS. This means that the CSI-RS allocation of the first method can be established based on a System Information Block (SIB) or Radio Resource Control (RRC). On the other hand, the first type of CSI-RS for the P1BM and the tracking RS may not be allocated according to the selection of the base station. The base station may indicate whether the first type of CSI-RS is allocated to the terminal in a Master Information Block (MIB).

Table 1 below shows specific parameters for setting the first type of CSI-RS. The CSI-RS is always set to be transmitted periodically.

[ Table 1]

Depending on the particular parameter values used for the first type of CSI-RS setting, various embodiments are possible below.

Table 2 below is an embodiment that can be used for P1BM only without tracking RS support. Specific CSI-RS allocation results according to the following embodiments are illustrated in fig. 4 and 5.

Fig. 4 is a diagram illustrating QCL relationships between an SS block and a first CSI-RS (= cell-specific RS) according to an embodiment of the present disclosure.

Fig. 5 is a diagram illustrating an embodiment of a method of configuring a first CSI-RS (= cell-specific RS) according to an embodiment of the present disclosure.

Referring to fig. 4, csi-RS resource sets 0, 1, 2, and 3 each have a QCL relationship with

SS block indices

0, 1, 2, and 3. At this time, it means that at least one of the L terminal beams searched in the SS block having the QCL relationship may be used in the CSI-RS having the QCL relationship.

Referring to fig. 5, since two OFDM symbols are used in each resource set and each symbol is set to 8 resources (Rsc), a total of 16 CSI-RS resources are repeatedly allocated on a frequency basis in one resource as shown in fig. 5. Since a total of 4 resource sets are set, a total of 64 CSI-RS resources can be set in the terminal by the setting illustrated in table 2 below.

[ Table 2]

Table 3 below shows an embodiment that supports tracking RS. Specific CSI-RS allocation results according to the following embodiments are illustrated in fig. 6.

Fig. 6 is a diagram illustrating an embodiment of a method of configuring a first CSI-RS (= cell-specific RS) (tracking RS support) according to an embodiment of the present disclosure.

Referring to fig. 6, since the number of resources per symbol is 4 and a total of 4 symbols (the number of symbols per resource set is 2 × the order of sub-time units 2=4) are allocated in one resource set, a total of 16 CSI-RS resources are allocated in one resource set. Meanwhile, since the time domain repetition distance is allocated as D =4, CSI-RS resources corresponding to a corresponding resource set are repeatedly allocated to positions separated by 4 symbols on the basis of a subcarrier spacing of 60KHz, as shown in fig. 6.

[ Table 3]

Table 4 below illustrates an embodiment supporting two antenna ports. Specific CSI-RS allocation results according to the present embodiment are illustrated in fig. 7A and 7B.

Fig. 7A and 7B are diagrams illustrating embodiments of methods of configuring a first CSI-RS (supporting two antenna ports) (tracking RS support) according to various embodiments of the present disclosure.

Referring to fig. 7A and 7B, one CSI-RS resource having two antenna ports is allocated to two adjacent REs on a frequency axis, unlike the previous embodiment of the present disclosure.

[ Table 4]

/>

The second type of CSI-RS may be used for P2 BM and P3 BM. This can be distinguished from the first type of CSI-RS allocation method in terms of the following aspects.

Periodic or aperiodic

■ Sub-time unit order (L) is dynamically indicated by DCI for aperiodic transmission

■ Sub-time unit order (L) configured by RRC or MAC CE for aperiodic transmission

-UE specific configuration by RRC or MAC CE

-if a sub-time unit is triggered, the resource ID is the same between sub-time units in the same RE position. (for P3 support)

Time-domain repetition with D symbol separation is not supported (i.e. no CFO tracking support)

QCL association with CSI-RS for P1BM

■ This association applies to the SS block if the CSI-RS for the P1BM is not configured.

The third type of CSI-RS may be used for P2 BM and MIMO CSI. This may use the same method of allocating CSI-RS as used in existing full-dimensional MIMO (FD-MIMO) for Long Term Evolution (LTE).

Fig. 8 is a diagram illustrating a configuration of a base station according to an embodiment of the present disclosure.

Referring to fig. 8, a base station processor 810 according to an embodiment of the present disclosure may perform a beam search and setup procedure using information received and transmitted through a base station receiver 820 and a base station transmitter 830. The base station processor 810 may control the base station receiver 820 and the base station transmitter 830 and may perform a base station operation according to an embodiment of the present disclosure.

Fig. 9 is a diagram illustrating a configuration of a terminal according to an embodiment of the present disclosure.

Referring to fig. 9, a terminal processor 910 according to an embodiment of the present disclosure may perform a beam search and setup procedure using information received and transmitted through a terminal receiver 920 and a terminal transmitter 930. The terminal processor 910 may control the terminal receiver 920 and the terminal transmitter 930 and may perform a terminal operation according to an embodiment of the present disclosure.

Another CSI-RS resource setting method according to the present disclosure will be described below, and the CSI-RS may be used for P1, P2, and P3 BMs involved in the beam search and setting method. The base station may transmit the setting of the CSI-RS to the terminal through the MIB, SIB, or RRC. Meanwhile, the CSI-RS may not be allocated according to the selection of the base station, and the base station may indicate whether the CSI-RS is allocated to the terminal in the MIB or SIB.

Table 5 below shows specific parameters for setting the CSI-RS. The CSI-RS may be set to periodic transmission or aperiodic transmission. Meanwhile, activation/deactivation of the CSI-RS may be set for each resource set. For example, the CSI-RS resources set to be activated are periodically transmitted, and the transmission of the CSI-RS resources set to be deactivated is periodically stopped. If the terminal receives PDSCH scheduling in a slot including CSI-RS resources set to be periodically transmitted, the terminal may perform decoding on the assumption that PDSCH is not allocated in OFDM symbols including the CSI-RS resources.

[ Table 5]

Table 6 below shows a configuration example for CSI-RS resource set No.0 having a QCL relationship with SS block index No.0 (No. 0). The resource set is located in the 5 th symbol in the 10 th slot. At this time, the slot index follows the standard defined in the reference parameter set (numerology) signaled in the MIB. For example, assuming that the reference parameter set is 60Khz, a total of 40 slots may be defined within a 10ms radio frame (assuming a length of 0.25ms per slot). Meanwhile, assuming that the reference parameter set is 120Khz, a total of 80 slots (assuming a length of 0.125ms per slot) can be defined within a 10ms radio frame. The resource set is transmitted in the 5 th symbol based on a symbol index reference defined by f _ s KHz in the slot. For example, if the reference parameter set is 60KHz or 120KHz, a total of 56 or 28 symbols defined by f _ s =240KHz are included in one slot.

The sub-time unit order (L) is a parameter indicating how many sub-symbols a symbol is composed of. In the case of L =1, one symbol does not include a plurality of sub-symbols. In case of L >1, one symbol may be composed of L sub-symbols using an Interleaved Frequency Division Multiple Access (IFDMA) scheme. At this time, the same transmission signal is repeatedly transmitted between the sub-symbols, and the base station beam remains unchanged between the sub-symbols.

The time domain repetition indicator is a parameter indicating whether a symbol is repeated at a symbol level in the time domain. For example, when the value is set to 0, the resource set is located only in the 5 th symbol in the 10 th slot. The indicator value is set to 1 only if the value of N is greater than 1, and if the value of N is set to 1, the resource set defined in one OFDM symbol is repeatedly transmitted over N symbols.

The resource sets are repeatedly transmitted with a transmission period of "10 ms".

The density reduction parameter is a value set so that the resource set can use only a part of resources in the symbol defined by f _ s KHz. Since the gap (gap) =0RE, this example is an example that does not support the density reduction function.

[ Table 6]

The Resource Element (RE) mapping pattern for a particular CSI-RS resource shown in table 6 above is illustrated in fig. 10.

Fig. 10 is a diagram illustrating an RE mapping pattern of CSI-RS resources according to an embodiment of the present disclosure.

Referring to fig. 10, code Division Multiplexing (CDM) is not applied. As shown in fig. 10, the RE mapping pattern of K CSI-RS resources is shown repeatedly, frequency division multiplexed within the configured CSI-RS BW.

Fig. 11A, 11B, and 11C are diagrams illustrating a process of transmitting an SS block and a set of CSI-RS resources according to various embodiments of the present disclosure.

Referring to fig. 11A, 11B and 11C, in addition to CSI-RS resource set 0 having a QCL relationship with SS block index 0, if CSI-RS resource sets 1, 2 and 3 having a QCL relationship with

SS block indexes

1, 2 and 3 are configured in

symbol indexes

6, 7 and 8 in the same 10 th slot, the SS block and the CSI-RS resource sets are transmitted as shown in fig. 11A. Here, the SS blocks and CSI-RS resource sets indicated by the same color have the same QCL relationship. Assume that the same base station beam is used for transmission in sets of SS blocks and CSI-RS resources having QCL relationships associated with each other.

Referring to fig. 11B, CSI-RS resource sets 0, 1, 2, and 3 having a QCL relationship with

SS block indices

0, 1, 2, and 3 are transmitted based on a configured CSI-RS BW and a predetermined symbol position (based on a time unit length set based on an f _ s value). Referring to fig. 11C, a CSI-RS resource set may be transmitted through a predetermined base station beam determined based on the CSI-RS resource set, a resource index (CSI-RS), and a port index.

Further, one SS block may have a QCL relationship with several sets of CSI-RS resources. The terminal may search for a terminal beam suitable for receiving the CSI-RS resource associated with the SS block based on the SS block received signal strength.

Table 7 below is an example of defining two resource sets by using the density reduction parameter, in which "Alt 3) the gap between resource sets" is set by the density reduction method. The RE mapping pattern of the CSI-RS shown in table 7 below is illustrated in fig. 12.

Fig. 12 is a diagram illustrating an embodiment of an RE mapping pattern of CSI-RS according to an embodiment of the present disclosure.

Referring to fig. 12, two sets are each configured at the same slot/symbol position, and the gap and offset values are set to 8 REs, which are occupied by one resource group, to avoid overlap between resource groups belonging to different sets.

[ Table 7]

For example, table 8 below shows an example of defining four resource sets in one symbol using a density reduction parameter, and an RE mapping pattern of the corresponding CSI-RS is illustrated in fig. 13.

Fig. 13 is a diagram illustrating an embodiment of an RE mapping pattern of CSI-RS according to an embodiment of the present disclosure.

[ Table 8]

/>

Referring to fig. 13, for example, table 9 below is an example of defining two resource sets in one symbol by using a density reduction parameter. At this time, "Alt-2" defining the gap between resources is used. In this case, in order to avoid overlap between resources belonging to two sets, the number of REs of a resource occupied by one resource is 2, which is set for the gap and offset value. The RE mapping pattern of the corresponding CSI-RS is illustrated in fig. 14.

Fig. 14 is a diagram illustrating an embodiment of an RE mapping pattern of CSI-RS according to an embodiment of the present disclosure.

[ Table 9]

/>

Referring to fig. 14, several resource sets may be mapped to one OFDM symbol to be transmitted using the above-described density reduction method. The resource sets may be used for CSI-RSs transmitted at different Total Radiated Power (TRP). NW may be set in the terminal to enable measurement and reporting only for some set of resources. Further, the NW may be set in the terminal to enable measurement and reporting of a resource set having a QCL relationship with a corresponding SS block index based on the SS block index received from the terminal.

Table 10 below shows a sub-time unit setting method. If the sub-time unit order (L) value is set, REs of the CSI-RS are mapped at intervals of L x f _ s using the IFDMA method.

Fig. 15 is a diagram illustrating a mapping of one CSI-RS every two REs according to an embodiment of the present disclosure.

Referring to fig. 15, for example, when L =2 and f _ s =120KHz, as shown in fig. 15, one Cs-RS is mapped every two REs. At this time, one RE has a size of 120 KHz. As described above, one time unit length is defined by "1/120ms" based on the set f _ s value. A time axis signal repeated L times is observed in a time unit. The terminal may perform up to L times of Rx beam scanning (sweeparing) in a time unit. The sub-time unit order (L) value may be signaled more dynamically by the MAC CE.

[ Table 10]

Table 11 below is an example that may be used for P1BM only without tracking RS support. Specific CSI-RS allocation results according to the following embodiments are illustrated in fig. 16 and 17.

Fig. 16 is a diagram illustrating an embodiment that may be used for P1BM only without tracking RS support according to an embodiment of the present disclosure.

Fig. 17 is a diagram illustrating an embodiment that may be used for P1BM only without tracking RS support according to an embodiment of the present disclosure.

Referring to fig. 16, csi-RS resource sets 0, 1, 2, and 3 each have a QCL relationship with

SS block indices

Referring to fig. 17, also, since two OFDM symbols are used in each resource set and 8 resources are set per symbol, a total of 16 CSI-RS resources are repeatedly allocated on a frequency basis in one resource as shown in fig. 17. Since a total of 4 resource sets are set, a total of 64 CSI-RS resources can be set in the terminal by the setting illustrated in table 11 below.

[ Table 11]

/>

Table 12 below shows an embodiment that supports time domain repetition. Specific CSI-RS allocation results according to the following embodiments are illustrated in fig. 18.

Fig. 18 is a diagram illustrating an embodiment supporting time-domain repetition according to an embodiment of the present disclosure.

Referring to fig. 18, since the time domain repetition indicator value is set to 1, as shown in fig. 18, a resource set defined in one OFDM symbol based on a subcarrier spacing (f _ s) of 240KHz is repeatedly transmitted over N symbols. For example, the base station transmits the same resource set N times using the same Tx beam on N symbols, and the terminal may perform Rx beam scanning (P3 BM) corresponding to the maximum value of N × L times.

[ Table 12]

/>

Fig. 19 is a diagram illustrating an RE mapping pattern of CSI-RS as shown in table 13 below, illustrating a case where CDM is not applied between resources, according to an embodiment of the present disclosure.

Referring to fig. 19, on the other hand, when P =2, the following signal is applied to two REs allocated to one resource depending on whether CDM is applied between antenna ports.

-if CDM between antenna ports is not applied, applying X _k ＝[x _k ；0],Y _k ＝[0；y _k ]。

-if CDM between antenna ports is applied, then X is applied _k ＝[x _k ；x _k ],Y _k ＝[y _k ；-y _k ]。

The method of generating Xk and Yk according to whether CDM is applied between antenna ports is similarly applied to the following embodiments and fig. 19 to 23.

[ Table 13]

/>

Fig. 20 is a diagram illustrating an RE mapping pattern of CSI-RS according to an embodiment of the present disclosure, in which a case where CDM is applied between resources is illustrated.

Referring to fig. 20, an RE mapping pattern of CSI-RS is illustrated in the following table 14, in which a case where CDM is applied between resources is illustrated.

When CDM is applied, one resource is mapped on 2K REs, and transmission signal X of antenna port No.0 for the K-th resource _k And transmission signal Y of antenna port No. 1 _k The following are given.

X _k ＝[a _k X ₀ ；b _k X ₁ ；c _k X ₂ ；d _k X ₃ ；],Y _k ＝[a _k Y ₀ ；b _k Y ₁ ；c _k Y ₂ ；d _k Y ₃ ；]

[a ₀ ；b ₀ ；c ₀ ；d ₀ ]＝[1；1；1；1]

[a ₁ ；b ₁ ；c ₁ ；d ₁ ]＝[1；-1；1；-1]

[a ₂ ；b ₂ ；c ₂ ；d ₂ ]＝[1；1；-1；-1]

[a ₃ ；b ₃ ；c ₃ ；d ₃ ]＝[1；-1；-1；1]

[ Table 14]

/>

Fig. 21 is a diagram illustrating an RE mapping pattern of CSI-RS according to an embodiment of the present disclosure, and illustrates a case where CDM is not applied between resources.

Referring to fig. 21, an RE mapping pattern of CSI-RS is illustrated in the following table 15, in which a case where CDM is not applied between resources is illustrated. In fig. 21, when the L value is greater than 1, the resource is indexed by the RE in which the IFDM scheme is mapped.

[ Table 15]

Fig. 22 and 23 illustrate embodiments of defining several resource sets in one OFDM symbol according to embodiments of the present disclosure.

Referring to FIG. 22, there is shownThe case where two resource sets are set in one OFDM according to table 16 is described. For example, the k +1 th resource and the k-th resource belonging to the same set are subjected to RE mapping while being spaced by a gap =2RE. Furthermore, in order to avoid RE mapping overlap between different sets, they have different RE mapping start indexes (= offset values) for each set, and these values are set differently for each set by the offset values. In general, when SFDM resource sets are set in one OFDM symbol, a gap = P × (S) may be set commonly for all sets _FDM -1) RE, and offset values may be set to 0RE, P RE, _FDM -1)RE。

[ Table 16]

Fig. 23 is a diagram illustrating a case where two resource sets are set in one OFDM according to an embodiment of the present disclosure.

Referring to fig. 23, a case where a gap between resource groups is set between two sets for FDM is shown according to table 17. Here, a resource group means K resources that are constituted by

resource indices

0, 1, …, K-1 and are continuous on the frequency axis. For example, RE mapping is performed between resource groups belonging to the same set while spacing slot =8 RE. Furthermore, to avoid RE mapping overlap between different sets, they have different RE mapping start indexes (= offset values) for each set, and these values are set differently for each set. In general, when SFDM resource sets are set in one OFDM symbol, a gap = P × K × (S) may be set commonly for all sets _FDM -1) RE, and offset values may be set to 0RE, P × K RE,. Ang, P × K × (S) for each set _FDM -1)RE。

[ Table 17]

Meanwhile, the CSI-RS resource setting proposed in the present disclosure may be made as followsThe parameters shown in table 18. The parameter indicated by (1) in table 18 below may be implicitly determined in a specific type of configuration method (e.g., cell-specific configuration). Meanwhile, the parameter indicated by (1) above may be explicitly indicated by the base station in another type of configuration method (e.g., UE-specific configuration). Can be based on the parameter S indicated by (2) above _FDM Automatically determine the gap and offset values.

Gap = "P × (S) _FDM -1)”RE

For the j-th frequency division multiplexed set, offset = "P × (j-1)" RE

In this case, the gap is treated as a parameter indicating the separation between resources belonging to the same set, and the offset value is treated as the starting RE mapping and has j =1, 2, ·, S _FDM The index of the same value. According to another embodiment of the present disclosure, the parameter S indicated by (2) above may be according to _FDM To automatically determine the gap and offset values as follows. At this time, the gap is treated as a parameter indicating the frequency at which the resource group is repeatedly mapped, how far apart the resource group is from the frequency base.

Gap = "P × (S) _FDM -1)”RE

For the j-th frequency division multiplexed set, offset = "P × (j-1)" RE

The symbol index indicated in the resource allocation shown in table 18 below indicates the symbol index at which RE mapping for S sets starts.

The CSI-RS set based on the parameters shown in table 18 below has the following characteristics.

-the RE mapping mode may be defined within the configured CSI-RSBW, regardless of the RB grid (grid).

For some use cases (e.g., P1 BM), OFDM symbols are configured with CSI-RS only within the configured CSI-RS BW.

The resource set may be defined within N OFDM symbols including NK resources.

( N >1 is required in the NR specification for further study. N may be a configurable parameter if desired )

Each resource may represent a beam identity of a particular TRP.

Multiple resource sets may be configured in a single resource setting and they may share the same RE mapping pattern.

Multiple resource sets may be configured in an FDM manner in N OFDM symbols.

-sub-time unit details

The time units may be determined by the indicated SCS, and the Tx beams may be changed between time units.

(i.e., the Tx beam is not changed within a time unit)

The number of sub-time units in a time unit is defined by the indicated repetition factor (e.g., 1, 2, 4), and the Rx beam may be varied across the sub-time units

Method for dividing IFDM used for sub-time unit

[ Table 18]

Meanwhile, the following table 19 may be used as a method of configuring the f _ s value and the L value, unlike the method shown in table 18. Here, the fSS block refers to a subcarrier spacing used for SS block transmission.

Fig. 24, 25, 26, 27, 28, and 29 are diagrams illustrating resource indexes and resource set indexes of CSI-RSs transmitted in one slot according to various embodiments of the present disclosure.

[ Table 19]

Referring to fig. 24, in case of N =1, K =4, P =2, L =1, f _ S = data channel SCS, SFDM =1, and S =14, a resource index and a resource set index of CSI-RS transmitted in one slot are indicated.

Referring to fig. 25, in case of N =1, K =8, P =2, L =1, f _ S = data channel SCS, SFDM =1, and S =14, a resource index and a resource set index of CSI-RS transmitted in one slot are indicated.

Referring to fig. 26, in case of N =1, K =4, P =2, L =2, f _ S = data channel SCS, SFDM =1, and S =14, a resource index and a resource set index of CSI-RS transmitted in one slot are indicated.

Referring to fig. 28, in case of N =2, K =4, P =2, L =1, f _ S = data channel SCS, SFDM =1, and S =7, a resource index and a resource set index of CSI-RS transmitted in one slot are indicated. In this case, the "time domain repetition indicator for N symbols" may be set to OFF.

Referring to fig. 29, in case of N =2, K =4, P =2, L =1, f _ S = data channel SCS, SFDM =1, and S =7, a resource index and a resource set index of CSI-RS transmitted in one slot are indicated. In this case, the "time domain repetition indicator for N symbols" may be set to ON.

The fourth embodiment: enabling request of SP-CSI-RS resource

Based on the resource setting method as described above, the base station can operate CSI-RS configured by two different schemes illustrated in table 20 below. In this case, the cell-specifically configured CSI-RS may be used in MIB or SIB for P1BM and UE-specifically configured CSI-RS may be used in RRC for P2 BM. The CSI-RS for P1BM may be configured specifically using RRC UE. The CSI-RS for P1BM may include as many resource sets as SS blocks sent by the base station. For example, if the base station periodically transmits a total of T SS blocks corresponding to

indexes

0, 1,.. And T-1, the base station may periodically transmit CSI-RS resource sets corresponding to resource set

indexes

0, 1,.. And T-1 for the P1 BM.

For the cell-specifically configured CSI-RS resource sets, a semi-persistent transmission scheme is established in the base station, and information on whether each resource set is enabled may be broadcast to the terminals in the SIB. The information on whether each resource set is enabled may use a bitmap having a size corresponding to the number of resource sets configured in the corresponding cell. For example, when a total of 64 resource sets are configured, the base station may indicate an index corresponding to an enabled resource set by 1 and an index corresponding to a disabled resource set by 0 using a bitmap having 64 bits. The terminal may perform measurements and reporting on the enabled set of resources. In addition, the terminal may measure the received signal strength of the SS block and determine the optimal SS block index based on the received signal strength. When a CSI-RS resource set having a QCL relationship with the best SS block index is in a deactivated state, the terminal may transmit information requesting activation of the corresponding CSI-RS resource set to the base station. The UE-specific configuration of CSI-RS may be performed using RRC. Whether each set of CSI-RS resources is enabled may be UE-specifically transmitted through RRC signaling or MAC CE. As shown in table 22 below, the base station may transmit information on whether a CSI-RS resource set corresponding to CSI-RS resource set

indexes

0, 1,. And T-1 for P1BM is enabled to the terminal using a bitmap having a length T. For example, when a CSI-RS resource set corresponding to an index T is enabled, a T-th bit value of a bitmap having a length T has '1', and when the CSI-RS resource set corresponding to the index T is disabled, a T-th bit value of a bitmap having a length T has '0'.

[ Table 22]

CSI-RS_active＝{00111010........0}

Meanwhile, UE-specifically configured CSI-RS may be used for P2 BM. If the CSI-RS for P1BM is cell-specifically configured, QCL information with the cell-specifically configured CSI-RS resource set as described in option 2 of table 20 below may be included in the resource setting of the CSI-RS for P2 BM. Meanwhile, the base station may include QCL information with the SS block as described in option 1 of table 20 below in the resource setting of the CSI-RS for P2 BM.

According to another embodiment of the present disclosure, the CSI-RS for P1BM shown in table 21 below may be UE-specifically configured using dedicated RRC signaling.

Fig. 31 is a diagram illustrating QCL information between K1 CSI-RS resources for P1BM and K2 resources for P2 BM according to an embodiment of the present disclosure.

Referring to fig. 31, some of the P2 BM resources may be set to be in a deactivated state. The terminal may select the best CSI-RS resource index by performing a beam search on the K1 CSI-RS resources for P1 BM. Further, the information on whether the corresponding CSI-RS resource having the P2 level is set to be in an enabled state may be identified through a QCL relationship with the selected CSI-RS resource index having the P1 level. If the CSI-RS resource having the P2 level is set to be in a deactivated state, the terminal may request activation of the corresponding resource from the base station. The operation of a base station and its associated terminal is illustrated in fig. 3A and 3B. The base station sets a CSI-RS resource (or resource set) for a P1BM and a CSI-RS resource (or resource set) for a P2 BM in the terminal and indicates to the terminal whether each resource (or resource set) is enabled. The terminal performs a beam search on a resource (or a resource set) having a P1 level, which is set to be in an enabled state, to select a resource (or a resource set) corresponding to the best beam. Whether a corresponding resource (or resource set) having a P2 level is set to be in an enabled state is identified through a QCL relationship with the selected resource (or resource set) having a P1 level. If the resource (or resource set) having the P2 level is set to be in the deactivated state, the terminal may transmit signaling requesting switching to the activated state for the resource (or resource set) having the P2 level to the base station. In this embodiment of the present disclosure, the beam search and best index selection for CSI-RS for P1BM may be replaced with the beam search and best index selection for SS blocks for P1 BM. At this time, the base station may inform QCL information between the SS block index of the terminal P1BM and the resource (or resource set) for the P2 BM, and the terminal may transmit signaling requesting switching to the enabled state for the resource (or resource set) having the P2 level by the same method to the base station using the QCL information.

When defining the QCL relationship between the SS block and the SP-CSI-RS, the terminal may perform an activation request or a deactivation request for the set of SP-CSI-RS resources based on measurement information on the SS block. The request may be sent in the form of a MAC CE. If the base station periodically transmits an SS block corresponding to

SS block index

0, 1,.. And T, the base station may transmit information on whether a CSI-RS resource set corresponding to CSI-RS resource set

index

0, 1,.. And T for P1BM is enabled to the terminal using a bitmap having a length of T. For example, if the tth CSI-RS resource set is enabled, the tth bit value of the bitmap having the length T has "1", and if the tth CSI-RS resource set is disabled, the tth bit value of the bitmap having the length T has "0".

The number of CSI-RS resource sets in an active state set in one terminal may be set to K by the base station, where K < = T. An index set of SS blocks corresponding to the currently set K enabled CSI-RS resource sets is defined as follows.

SS_active＝{i1,i2,…,iK}

The base station may explicitly send information on the SS _ active set to the terminal. Alternatively, the terminal may implicitly identify information about SS _ active sets based on index information of SS blocks corresponding to enabled SP-CSI-RS resource sets through QCL relationship. An index set that is not included in SS _ active among all T SS block indexes is referred to as SS _ active (SS-inactive) in the following description.

In the following description, RSRP _ i refers to an RSRP value measured by a terminal for an SS block corresponding to SS block index i.

[ method 1a ]

-the terminal selecting N SS blocks corresponding to the higher N RSRP values based on the measured RSRP values of all SS blocks. At this time, the base station may set a value corresponding to N. (e.g., N = 1).

The terminal configures as Request _ SS _ active set the indexes not included in the SS _ active set among the selected upper N SS block indexes.

-Request _ SS _ active set reporting method

■ Method 1) when a base station requests a report, a terminal transmits the report. The transmission for the report may be performed periodically or may be transmitted non-periodically only when the base station requests the report.

■ Method 2) when the number of indexes included in a Request _ SS _ active set configured by the terminal is equal to or greater than the number of N _ reporting, the terminal transmits the Request _ SS _ active set to the base station through the MAC CE.

The N _ reporting value may be preset by the base station through RRC or MAC CE.

When reporting information about Request _ SS _ active set, all or some of the following information included in the following table 23 may be sent to the base station.

[ Table 23]

[ method 1b ]

-the highest value among RSRP values measured by the terminal for SS blocks corresponding to indexes included in the SS _ acitve set is defined as a reference RSRP shown in the following equation (1).

RSRP _ ref = max (RSRP _ i) for all i ∈ SS _ active

Among RSRP measurement values of SS blocks corresponding to indexes included in the SS _ active set, indexes of SS blocks corresponding to RSRP values higher than a reference RSRP value by more than a threshold set by the base station are configured as a Request _ SS _ active set (see table 24).

[ Table 24]

Request _ SS _ active = { j | RSRP _ j > RSRP _ ref + threshold } for all j ∈ SS _ active

-if an SS block index equal to or greater than the N _ reporting number is included in the Request _ SS _ active set, the terminal sends the Request _ SS _ active set to the base station using the MAC CE.

■ The N _ reporting value may be preset by the base station through RRC or MAC CE.

In the above embodiments of the present disclosure, the value of "RSRP _ ref (RSRP reference)" may be set to a specific value by the base station in advance.

In the above embodiments of the present disclosure, the base station may change and set the SP-CSI-RS currently set in the deactivated state to the activated state based on the Request _ SS _ active report. The change of the enabled setting may be performed by the MAC-CE, and the terminal may update the SS _ active set and the Request _ SS _ active set based on the changed setting.

According to another embodiment of the present disclosure, one SS block index may have a QCL relationship with one or more SP-CSI-RS resources. The QCL relationship may be previously transmitted to the terminal through RRC or MAC CE. The total number of SS blocks periodically transmitted by the base station may be less than the T2 value described below.

The base station may transmit whether the CSI-RS is enabled to the terminal using a bitmap message having a length T2 shown in table 22 below. At this time, when the T-th CSI-RS resource is enabled, the T-th bit value of the bitmap having the length T2 has "1", and when the T-th CSI-RS resource is disabled, the T-th bit value of the bitmap having the length T2 has "0".

[ method 2a ]

The terminal selects a CSI-RS resource index having a QCL relationship with the higher N SS block indices.

-indexes of CSI-RS resource sets in deactivated state among the selected CSI-RS resource indexes are collected and configured as Request _ CSI-RS _ active sets shown in table 25 below.

-when the number of indexes included in the Request _ SS _ active set configured by the terminal is equal to or greater than the N _ reporting number, the terminal transmits the Request _ SS _ active set to the base station through the MAC CE.

[ Table 25]

Request_CSI-RS_active＝{CRI_j1，CRI_j2...，}

In the following description, CSI-RS _ RSRP _ i refers to an RSRP value obtained by averaging RSRP values measured by a terminal in all antenna ports included in CSI-RS resources corresponding to CSI-RS resource index i. In the following description, it is assumed that the terminal can measure an RSRP value for the deactivated CSI-RS. In order to measure the RSRP value of the terminal, the base station may send information to the terminal as to whether the RSRP value can be measured in the deactivated CSI-RS to the MS.

[ method 2c ]

The terminal defines a highest value among RSRP measurement values for the enabled CSI-RS resources as a reference RSRP.

Equation 2 for all CRI i.. Times.rsrp _ ref = max (CSI-RS _ RSRP _ i) corresponding to enabled CSI-RS resources

-performing RSRP measurements on the deactivated CSI-RS resources, and the index of the CSI-RS resource corresponding to an RSRP value higher than the reference RSRP value of equation 2 above by a threshold set by the base station is configured as a Request _ CSI-RS _ active set shown in table 26 below.

[ Table 26]

In the above embodiment of the present disclosure, the value of "RSRP _ ref (RSRP reference)" may be set as a specific value by the base station in advance.

Fifth embodiment: OFDM symbols for dedicated CSI-RS transmission

The terminal may assume that signals/channels other than CSI-RS are not frequency division multiplexed in OFDM symbols in which CSI-RS resources for P1 or P2 BM are configured. For example, a terminal receiving PDSCH scheduling for a slot including an OFDM symbol in which CSI-RS is configured may perform decoding on the assumption that PDSCH signals are transmitted only to the remaining symbols except for the corresponding OFDM symbol in the slot. Meanwhile, if transmission of the CSI-RS resource set is deactivated, the terminal may assume that another signal/channel other than the CSI-RS is transmitted to an OFDM symbol in which the corresponding CSI-RS is configured. For example, a terminal receiving PDSCH scheduling for a slot including an OFDM symbol in which a deactivated set of CSI-RS resources is configured may perform decoding under the assumption that PDSCH signals are transmitted in the slot even to the corresponding OFDM symbol.

Fig. 30 is a diagram illustrating a process of performing resource setting with indexes of S1, S2.

Referring to fig. 30, a base station 3000 may perform resource setting with indexes of S1, S2. Information on the resource set index set to be in an enabled state in which dual transmission is actually performed may be transmitted as { Sactive } to the terminal 3010. When the terminal 3010 receives scheduling from the base station 3000 in a slot in which a resource set belonging to a received { Sactive } index set is set, the terminal 3010 may perform decoding on the assumption that a PDSCH signal is transmitted only to the remaining symbols except for OFDM symbols in the slot. Base station 3000 can dynamically indicate { Sactive } information to terminal 3010 each time the { Sactive } information is updated. The base station 3000 may set CSI-RS BW to which CSI-RS is sent for each resource set when performing resource setting. The CSI-RS BW may be different for each resource set, or the same CSI-RS BW may be set for each resource set. When the terminal 3010 is in an enabled state for a resource set in which the CSI-RS BW is set, the terminal 3010 may perform decoding under the following assumption: in the remaining frequency periods except for the CSI-RS BW, the PDSCH is transmitted to the OFDM symbol in which the resource set is configured. Meanwhile, when performing resource setting, the base station 3000 may set whether FDM transmission of CSI-RS and PDSCH is possible for each resource set. For example, for a resource set to disable (disable) FDM transmission of CSI-RS and PDSCH, decoding may be performed under the following assumption: the PDSCH is not transmitted to the entire system BW or the configured CSI-RS BW in the OFDM symbol in which the corresponding resource set is configured as described above. Meanwhile, for a resource set to enable FDM transmission of PDSCH, decoding may be performed under the following assumption: PDSCH transmission is performed on the remaining REs except for REs in which non-zero-power CSI-RS or zero-power CSI-RS transmission is performed.

[ Table 20]

[ Table 21]

The sixth embodiment: RE mapping method of CSI-RS for beam management

According to the CSI-RS setting method proposed in the present disclosure, one CSI-RS resource (or port group) may be allocated to one OFDM symbol.

Fig. 32 is a diagram illustrating CSI-RS resource setting between a base station and a terminal according to an embodiment of the present disclosure.

Fig. 33 is a diagram illustrating a case where K CSI-RS resources (or port groups) are allocated to one OFDM symbol according to an embodiment of the present disclosure.

Referring to fig. 32 and 33, embodiments of the cases of K =1, 2, 4 and 8 are illustrated. It is illustrated that K resources (or port groups) are sequentially and repeatedly mapped to one OFDM symbol in frequency. The OFDM symbol length in which one CSI-RS is transmitted is referred to as a time unit, and the length of the time unit is determined by the fs value set by the base station as described above.

Fig. 34 is a diagram illustrating a case where one resource or port group is mapped to NP × L REs according to an embodiment of the present disclosure.

Referring to FIG. 34, one resource or port group is mapped to N _P Xl REs, which is illustrated in fig. 34. Here, from f _CSI-RS,BM The indicated value having the same f as above _s The same meaning, merely identifying different labels. N is a radical of _P Denotes the number of antenna ports that can be included in one resource (or port group), and L denotes the number of sub-time units that can be set in one time unit. As described above, the terminal may perform Rx beam scanning up to L times in one time unit.

For RE mapping of CSI-RS for beam management, the same method as table 27 below may be used. This corresponds to the case of K =1 in the above embodiment.

[ Table 27]

The RE mapping of non-zero power CSI-RS (nzp CSI-RS) for a specific OFDM symbol may be set as shown in table 27 below. The above setting may be performed as shown in table 28 below. The settings may include timing information "Symbol _ location _ info" (Symbol position information) and "Slot _ location _ info" (Slot position information) regarding symbols and slots to which K resources are transmitted. If the K resources are periodic or semi-persistent CSI-RS, the settings may include a parameter "Periodicity" associated with the transmission period. The setting may not include the value of the parameter "Periodicity" if the K resources are periodic or aperiodic CSI-RS. For the setting of the RE mapping method for K resources, the setting may include a field "nzp _ resourceConfig". The field may include a parameter K [ resources ] for indicating how many resources are transmitted at the set symbol position. The field may include a value of a parameter X [ port ] indicating how many antenna ports the resource is configured. At this time, each of the K resources may be composed of resources having X [ ports ]. The field may include a value of D RE/RB/port to set the density of one antenna port. For example, each of the antenna ports included in the K resources is transmitted at a symbol position set at a density D. In the case of X =1[ port ], the value D may be represented by D = 12/(LK) [ RE/RB/port (port) ] based on the parameters illustrated in fig. 33 and 34. For any X = [ port ] value, the value D may be represented by D = 12/(LXK) [ RE/RB/port ] based on the parameters illustrated in fig. 33 and 34. The field may include a RE _ mapping _ offset [ RE ] parameter including information on RE positions where RE mapping of K resources starts. For example, for a total of M PRBs corresponding to PRB indices "I" through "I + M-1", if K resources are transmitted when RE mapping is performed as shown in fig. 33 and 34, the position where RE mapping starts is the RE _ mapping _ offset [ RE ] th REs in the PRB corresponding to the PRB index I. For example, when RE _ mapping _ offset values are set differently in different CSI-RS settings and all the remaining parameters are set as such, the locations where CSI-RSs transmitted at each setting are RE-mapped may be made not to overlap each other. In this case, based on the value of the parameter L of fig. 34, RE _ mapping _ off values are 0, 1.

[ Table 28]

The base station may allocate zero power CSI-RS (ZP CSI-RS) resources to the remaining REs except for REs corresponding to RE mapping of the NZP CSI-RS resources. The base station may inform the terminal whether the ZP CSI-RS resources are set in the remaining REs when the NZP CSI-RS resources are set. The setting of resources may be performed as shown in table 29. The "NZP-resourceConfig" field sets the RE position corresponding to one or more NZP CSI-RS resources. The "ZP-resourceConfig" field is a field for setting whether the ZP CSI-RS resource corresponds to an RE position other than the RE position corresponding to the NZP CSI-RS resource(s). For example, when "ZP-resourceConfig = { On }", one ZP CSI-RS resource is set to correspond to the remaining RE positions.

[ Table 29]

If the base station simultaneously sets ZP CSI-RS and NZP CSI-RS in the terminal using the following table 29, it can be assumed for the terminal that the time domain repetition pattern occurs L times in the OFDM symbol interval.

Referring to fig. 36, when the relevant parameter is set to L =4 in table 27 below, if the CSI-RS is set in the terminal using method 2, the terminal sets a sub-time unit OFDM symbol having L =4 in one OFDM symbol interval. The terminal may apply different terminal reception beams for each sub-time unit, and may search for an optimal terminal reception beam by comparing the reception intensity for each sub-time unit.

According to the CSI-RS setting method proposed in the present disclosure, a plurality of resource sets may be set in one OFDM symbol as described above. In the present disclosure, the term resource group may be replaced by another expression having the same meaning as the above-mentioned resource set.

Fig. 35 is a diagram illustrating an embodiment of a case where two resource groups are set in one OFDM symbol according to an embodiment of the present disclosure. Each resource group may be transmitted from a different base station antenna panel (panel) or TRP.

Referring to fig. 35, according to another embodiment of the present disclosure, the resource setting of the CSI-RS having K resources in one OFDM symbol may be set as follows. The following arrangement may be equally applied to several OFDM symbols. At this time, the following settings shown in the following table 31 may also include information on OFDM symbol positions and slot positions.

Table 30 below shows a method for setting K CSI-RS resources in one OFDM symbol based on the RE mapping method for a single antenna port described in table 27 below. Determining D [ RE/RB/port according to configuration index value]Indicating the density of one antenna port mapped by the RE on a frequency basis, and determining a value of K, which is the number of resources to be set in one OFDM symbol. To prevent collision of the locations of the RE mapping on the frequency basis among the K resources, a different RE mapping offset (δ) for each resource is determined based on the values in the following table 30 ^k ). For example, according to configuration index No.0 (No. 0), K =2 resources are set in one OFDM symbol. In the bandwidth in which the CSI-RS is set, the first resource indicates that the RE mapping starts from RE No.0, and the second resource indicates that the RE mapping starts from RE No. 1. Since the above parameters are automatically determined when only the configuration index value is given, it is sufficient to include only the configuration index value in the CSI-RS resource setting.

Meanwhile, all K resources may be set to non-zero power (NZP) CSI-RS, and some of them may be set to Zero Power (ZP) CSI-RS. To increase the accuracy of L1-RSRP measurement in the serving cell and facilitate measurement of interference of neighboring cells, the allocation patterns of NZP CSI-RS and zp CSI-RS between cells may not overlap each other. As with the method, a bitmap "b" having a length K ₀ b ₁ …b _K-1 "may be included in the CSI-RS resource setting. If bk is set to '1' in the bitmap, the (k + 1) th resource set in the CSI-RS resource setting is set to the NZP CSI-RS. If bk is set to '0' in the bitmap, the (k + 1) th resource set in the CSI-RS resource setting is set to the ZP CSI-RS.

The CSI-RS resource setting may be equally set in different terminals. The CSI-RS may be set to SP CSI-RS, and only some of the resources therein may be UE-specifically enabled.

Table 30: configuration of K SP CSI-RS resources with Single antenna Port (type 1)

(1) Need to be included in the CSI-RS resource setting

The above embodiments may be used as a setting method of a P CSI-RS or an AP CSI-RS in which periodic transmission is performed. For example, the resource setting of the CSI-RS may be performed as shown in table 31 below.

[ Table 31]

According to another embodiment of the present disclosure, in resource setting of CSI-RS having K resources in one OFDM symbol, each of D, K and δ may be set as shown in table 32 below ^k The value of (c). Unlike table 30 above, in the setting related to table 32 below, indexes (or D), K, X, and δ are configured ^k Should be specifically included at the time of resource setting for the CSI-RS. At this time, RE mapped REs that are not used for the K resources may be generated in the OFDM symbol to which the CSI-RS is set according to which value K is set. The resource setting of the CSI-RS may include a "zp-resourceConfig" field, which may be represented by 1 bit. If the value of this field is set to "On", the terminal may assume that ZP CSI-RS is set for REs mapped to REs not used for K resources. On the other hand, if the value of this field is set to "OFF", it means that the terminal should not make any assumption about REs not used for RE mapping of K resources.

Table 32: configuration of K P/AP CSI-RS resources with Single antenna Port (type 2)

(1) Need to be included in the CSI-RS resource setting

The above embodiments may be used as a setting method of an AP CSI-RS in which periodic transmission is performed. For example, the resource setting of the CSI-RS may be performed as shown in the following table 33. The following arrangement may be equally applied to several OFDM symbols. At this time, the following settings shown in the following table 33 may also include information on OFDM symbol positions.

[ Table 33]

(1) Substitution by D [ RE/RB/Port ] parameter

According to another embodiment of the present disclosure, in the resource setting of the CSI-RS having K resources in one OFDM symbol, the parameters shown in the following 34 may be used. The resource setting of the CSI-RS may be performed as shown in table 35 below. For example, if only the value of "configuration index" is indicated to the terminal, the terminal may find the values of the remaining parameters D, X, K and δ k based on the following table 34.

[ Table 34]

/>

[ Table 35]

Meanwhile, in the above-described embodiments of the present disclosure, the "Slot _ location _ info" field included in the resource setting related to the P/SP CSI-RS (in which the periodic transmission is performed) transmits the location information of the Slot through which the CSI-RS is set in the resource setting to the terminal. The "Slot _ location _ info" field may be configured as shown in table 36 below. For example, the start position where the slot is allocated is indicated as "Starting _ slot _ index", and the Number of Slots consecutively allocated from the start position may be indicated as "Number _ of _ consecutives _ Slots". For example, in the case of the following table 36, the CSI-RS set in the resource setting is transmitted in Y consecutive slots from the xth slot position.

[ Table 36]

Meanwhile, the setting of the slot position may be performed as shown in the following table 37. For example, for Y consecutive Slots from the xth slot position, the "Configured _ Slots" field may specifically indicate slot positions of CSI-RSs to be transmitted through a bitmap having a length of Y. For example, when bi is "1", the position of the "X + i" th slot indicates a slot for transmission of the CSI-RS. When bi is "0", the position of the "X + i" th slot indicates to the terminal that the slot is used for transmission of the CSI-RS.

[ Table 37]

In the above embodiments of the present disclosure, "Symbol _ location _ info" included in the resource setting transmits, to the terminal, the location information of the OFDM Symbol to which the CSI-RS is transmitted in the slot indicated by the resource setting. For example, the slot corresponds to a slot indicated by a method shown in, for example, table 36 or table 37 above, and the CSI-RS is commonly transmitted at an OFDM Symbol position indicated by the "Symbol _ location _ info" field for all slots. Meanwhile, in the case of an AP CSI-RS in which aperiodic transmission is performed, DCI indicating transmission of the AP CSI-RS may explicitly transmit a slot position at which the AP CSI-RS is transmitted.

The information sent in the "Symbol _ location _ info" field may consist of a length 14 bitmap b0b1 … b13, such as shown in table 38 below. If the bi-bit in the bitmap is set to "1", it indicates to the terminal that the ith OFDM symbol in the slot is used for CSI-RS transmission. If the bi-bit in the bitmap is set to "0", it indicates to the terminal that the ith OFDM symbol in the slot is not used for CSI-RS transmission.

[ Table 38]

Symbol_location_info＝{b ₀ b ₁ ...b ₁₃ }

While the disclosure has been shown and described with reference to various embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the disclosure as defined by the appended claims and their equivalents.

Claims

1. A method performed by a user equipment, UE, for beam management, the method comprising:

receiving channel state information reference signal, CSI-RS, resource information from a base station, the CSI-RS resource information including a repetition indicator indicating whether a set of CSI-RS resources is repeated at a symbol level in a time domain; and

receiving a CSI-RS corresponding to a CSI-RS resource set from a base station based on the CSI-RS resource information,

wherein, in case the repetition indicator indicates that a set of CSI-RS resources is repeated in a symbol level in a time domain, CSI-RS resources within the set of CSI-RS resources are repeatedly received from the base station on N symbols on a same transmission beam, where N is greater than 1.

2. The method of claim 1, wherein CSI-RS resource information comprises at least one of a synchronization sequence, SS, block index having a spatially quasi co-located, QCL, relationship with a set of CSI-RS resources, resource allocation information for a set of CSI-RS resources, and a transmission period for a set of CSI-RS resources.

3. The method of claim 1, wherein the first and second light sources are selected from the group consisting of,

wherein, in the case that the repetition indicator indicates that the set of CSI-RS resources do not repeat at a symbol level in a time domain, transmission of the CSI-RS resources within the set of CSI-RS resources is positioned in a designated symbol.

4. The method of claim 3, further comprising:

in the case where the repetition indicator indicates that the set of CSI-RS resources is repeated at a symbol level in a time domain, a beam sweep corresponding to a maximum of the number of symbols N multiplied by the sub-time unit order L is performed.

5. The method of claim 1, wherein CSI-RS resource information is received via one of a master information block, MIB, a system information block, SIB, or a radio resource control, RRC, message.

6. A method performed by a base station for beam management, the method comprising:

transmitting channel state information reference signal (CSI-RS) resource information to User Equipment (UE), the CSI-RS resource information including a repetition indicator indicating whether a CSI-RS resource set is repeated at a symbol level in a time domain; and

transmitting CSI-RS corresponding to the CSI-RS resource set to the UE based on the CSI-RS resource information,

wherein, in case the repetition indicator indicates that the CSI-RS resource set is repeated at symbol level in the time domain, the CSI-RS resources within the CSI-RS resource set are repeatedly transmitted on N symbols using the same transmission beam of the base station, wherein N is greater than 1.

7. The method of claim 6, wherein the CSI-RS resource information comprises at least one of a synchronization sequence, SS, block index having a spatial quasi co-located, QCL, relationship with the set of CSI-RS resources, resource allocation information for the set of CSI-RS resources, and a transmission period for the set of CSI-RS resources.

8. The method of claim 6, wherein the first and second light sources are selected from the group consisting of,

9. The method of claim 8, wherein in a case that the repetition indicator indicates that the set of CSI-RS resources is repeated in a symbol level in a time domain, performing a beam sweep corresponding to a maximum of a number N of symbols multiplied by a sub-time unit order L.

10. The method of claim 6, wherein the CSI-RS resource information is transmitted via one of a master information block, MIB, a system information block, SIB, or a radio resource control, RRC, message.

11. A user equipment, UE, for performing beam management, the UE comprising:

a transceiver; and

a controller configured to:

receiving, via a transceiver, channel state information reference signal, CSI-RS, resource information from a base station, the CSI-RS resource information including a repetition indicator indicating whether a set of CSI-RS resources is repeated at a symbol level in a time domain; and

receiving, via the transceiver, a CSI-RS corresponding to the CSI-RS resource set from the base station based on the CSI-RS resource information,

wherein, in case the repetition identifier indicates that a set of CSI-RS resources is repeated in a symbol level in a time domain, CSI-RS resources within the set of CSI-RS resources are repeatedly received from the base station on N symbols on a same transmission beam, where N is greater than 1.

12. The UE of claim 11, wherein the CSI-RS resource information comprises at least one of a synchronization sequence, SS, block index having a spatial quasi co-located, QCL, relationship with the set of CSI-RS resources, resource allocation information for the set of CSI-RS resources, and a transmission periodicity for the set of CSI-RS resources.

13. The UE of claim 11, wherein the UE is further configured to,

wherein, in the case that the repetition indicator indicates that the set of CSI-RS resources is repeated in the time domain at the symbol level, the transmission of the CSI-RS resources within the set of CSI-RS resources is positioned in a specified symbol, and

wherein the CSI-RS resource information is received via one of a master information block MIB, a system information block SIB or a radio resource control RRC message.

14. A base station for performing beam management, the base station comprising:

a transceiver; and

a controller configured to:

transmitting, via a transceiver, channel state information reference signal, CSI-RS, resource information to a user equipment, UE, the CSI-RS resource information including a repetition indicator indicating whether a set of CSI-RS resources is repeated at a symbol level in a time domain; and

transmitting, via the transceiver, CSI-RS of the CSI-RS resource set to the UE based on the CSI-RS resource information,

wherein, in case the repetition indicator indicates that the set of CSI-RS resources is repeated at symbol level in the time domain, the CSI-RS resources within the set of CSI-RS resources are repeatedly transmitted on N symbols with the same transmission beam of the base station, wherein N is greater than 1.

15. The base station of claim 14, wherein the CSI-RS resource information comprises at least one of a synchronization sequence SS block index having a spatially quasi co-located QCL relationship with the set of CSI-RS resources, resource allocation information for the set of CSI-RS resources, and a transmission periodicity for the set of CSI-RS resources, and

wherein, in a case that the repetition indicator indicates that the set of CSI-RS resources is repeated at a symbol level in a time domain, transmission of the CSI-RS resources within the set of CSI-RS resources is positioned in a designated symbol.