KR102448673B1 - Communication method and apparatus using multiple antennas in wireless communication system - Google Patents

Abstract

A communication method and apparatus using multiple antennas in a wireless communication system are disclosed. A communication method of a receiver includes receiving reference signals from a transmitter of a communication system through beams to which hybrid beamforming is applied, and based on the reference signals, at least one of analog beams belonging to the beams having a quality equal to or greater than a preset threshold value selecting an analog beam of , selecting at least one digital beam corresponding to the at least one analog beam from among the digital beams belonging to the beams and having a quality equal to or higher than the preset threshold based on the reference signals includes Accordingly, the performance of the communication system may be improved.

Description

COMMUNICATION METHOD AND APPARATUS USING MULTIPLE ANTENNAS IN WIRELESS COMMUNICATION SYSTEM

The present invention relates to a wireless communication technology, and more particularly, to a wireless communication technology for providing an improved communication service using multiple antennas.

In a wireless communication system, a user equipment may generally transmit/receive a data unit through a base station. For example, when there is a data unit to be transmitted to the second terminal, the first terminal may generate a message including the data unit to be transmitted to the second terminal, and transmit the generated message to the first base station to which it belongs. can be transmitted The first base station may receive the message from the first terminal, and may confirm that the destination of the received message is the second terminal. The first base station may transmit the message to the second base station to which the second terminal, which is the confirmed destination, belongs. The second base station may receive the message from the first base station, and may confirm that the destination of the received message is the second terminal. The second base station may transmit the message to the second terminal that is the confirmed destination. The second terminal may receive the message from the second base station, and may obtain a data unit included in the received message.

Meanwhile, as the number of users of the aforementioned wireless communication system increases, an efficient communication method will be required to improve communication services. For example, communication based on multiple antennas may be considered to improve communication services. However, even when communication based on multiple antennas is performed, an improvement plan for the following issues will be required.

- Reduction of transmission delay

- Guaranteed reliability by improving data transmission/retransmission performance

- Providing services with flexibility and scalability to reflect terminal (eg, user) characteristics and service characteristics

- Provision of services in consideration of frequency operation regulations and frequency characteristics

- Transmission of large amounts of data or provision of high data rates according to user needs

An object of the present invention for solving the above problems is to provide a communication method and apparatus based on multiple antennas in order to provide an improved communication service.

In a communication method in a receiver of a communication system according to a first embodiment of the present invention for achieving the above object, receiving reference signals from a transmitter of the communication system through beams to which hybrid beamforming is applied; selecting at least one analog beam having a quality equal to or higher than a preset threshold value from among the analog beams belonging to the beams based on the reference signals; selecting at least one digital beam corresponding to and having a quality equal to or greater than the preset threshold, and transmitting information indicating at least one of the at least one analog beam and the at least one digital beam to the transmitter. include

Here, the selecting of the at least one analog beam includes selecting at least one horizontal analog beam having a quality equal to or higher than the preset threshold value from among the horizontal analog beams belonging to the analog beams, and the vertical analog beam belonging to the analog beams. The method may further include selecting at least one vertical analog beam having a quality equal to or higher than the preset threshold value from among the beams.

Here, the at least one vertical analog beam may be an analog beam disposed in a vertical direction to the at least one horizontal analog beam.

Here, the selecting of the at least one digital beam includes selecting at least one horizontal digital beam corresponding to the at least one horizontal analog beam from among the horizontal digital beams belonging to the digital beams and having a quality equal to or higher than the preset threshold value. The method may further include selecting at least one vertical digital beam corresponding to the at least one vertical analog beam and having a quality equal to or greater than the preset threshold value from among the vertical digital beams belonging to the digital beams.

Here, the at least one vertical digital beam may be a digital beam disposed in a vertical direction to the at least one horizontal digital beam.

Here, the reference signals may be received through the combined beam of the transmitter.

Here, the digital beams may be generated by electrical tilting of the analog beams.

Here, the selecting of the at least one digital beam may further include checking a precoding vector of the at least one digital beam.

In a communication method in a transmitter of a communication system according to a second embodiment of the present invention for achieving the above object, transmitting reference signals using analog beams and digital beams, at least one selected based on the reference signals receiving information indicative of at least one of an analog beam and at least one digital beam from a receiver of the communication system, and communicating with the receiver using at least one of the at least one analog beam and the at least one digital beam performing a method, wherein the antenna module of the transmitter includes a plurality of beamformers supporting different sectors, each of the plurality of beamformers includes a plurality of panels, and each of the plurality of panels includes a plurality of panels. antenna elements of , wherein the analog beams and the digital beams are transmitted by one beamformer.

Here, the reference signals may be transmitted through time-frequency resources excluding time-frequency resources configured for interference measurement.

Here, the at least one digital beam may be generated by electrical tilting of the at least one analog beam.

Here, the reference signals may be transmitted through a beam in which at least two of the analog beams and the digital beams are combined.

Here, the combined beam may be generated by virtualizing the panels belonging to one beamformer to have one directing point.

In order to achieve the above object, a receiver of a communication system according to a third embodiment of the present invention includes a processor and a memory in which at least one instruction executed by the processor is stored, and the at least one instruction is to which hybrid beamforming is applied. Receive reference signals from the transmitter of the communication system through beams, and select at least one analog beam having a quality equal to or greater than a preset threshold value from among analog beams belonging to the beams based on the reference signals, and the reference signal selecting at least one digital beam corresponding to the at least one analog beam and having a quality equal to or greater than the preset threshold value from among the digital beams belonging to the beams, and the at least one analog beam and the at least one and transmit information indicating at least one of the digital beams of the transmitter to the transmitter.

Here, when the at least one analog beam is selected, the at least one command selects at least one horizontal analog beam having a quality equal to or higher than the preset threshold value from among horizontal analog beams belonging to the analog beams, and the The method may further be performed to select at least one vertical analog beam having a quality equal to or higher than the preset threshold value from among vertical analog beams belonging to the analog beams.

Here, when the at least one digital beam is selected, the at least one command corresponds to the at least one horizontal analog beam among the horizontal digital beams belonging to the digital beams and includes at least one having a quality equal to or higher than the preset threshold value. select a horizontal digital beam of , and select at least one vertical digital beam corresponding to the at least one vertical analog beam from among vertical digital beams belonging to the digital beams and having a quality equal to or greater than the preset threshold value. .

Here, the at least one vertical analog beam may be an analog beam disposed in a vertical direction to the at least one horizontal analog beam, and the at least one vertical digital beam may be a digital beam disposed in a vertical direction to the at least one horizontal digital beam. It can be a beam.

Here, the reference signals may be received through the combined beam of the transmitter.

Here, the digital beams may be generated by electrical tilting of the analog beams.

Here, when the at least one digital beam is selected, the at least one command may be executed to confirm a precoding vector of the at least one digital beam.

According to the present invention, an improved communication service can be provided in a communication system. In particular, when communication is performed based on multiple antennas, an optimal beam (eg, an analog beam, a digital beam) can be selected through a beam finding procedure, so that communication performance can be improved. In addition, since the quality of the beam can be measured through a beam measurement procedure and communication can be performed using a beam having an optimal quality, communication performance can be improved. In addition, since interference between beams may be measured through a beam interference measurement procedure and interference may be controlled based on the measured result, communication performance may be improved.

1 is a conceptual diagram illustrating a first embodiment of a communication system.
2 is a block diagram showing a first embodiment of a communication node constituting a communication system.
3 is a conceptual diagram illustrating a first embodiment of a beamforming-based transmission method.
4 is a conceptual diagram illustrating a first embodiment of an antenna module.
5A is a conceptual diagram illustrating a first embodiment of a horizontal sector in a service area.
5B is a conceptual diagram illustrating a first embodiment of a vertical sector in a service area.
5C is a conceptual diagram illustrating a first embodiment of a sector configuration in a service area.
6 is a conceptual diagram illustrating a second embodiment of a sector configuration in a service area.
7 is a conceptual diagram illustrating a third embodiment of a sector configuration in a service area.
8 is a conceptual diagram illustrating a fourth embodiment of a sector configuration in a service area.
9 is a conceptual diagram illustrating a first embodiment of a panel in a beamformer.
10 is a conceptual diagram illustrating a first embodiment of a 2D URA antenna disposed in a panel.
11 is a graph illustrating a first embodiment of an antenna gain and a beam pattern according to beamforming.
12 is a conceptual diagram illustrating a first embodiment of a beamforming operation state transition diagram.
13A is a conceptual diagram illustrating a first embodiment of a beam pattern in a service area served by one beamformer.
13B is a conceptual diagram illustrating a second embodiment of a beam pattern in a service area served by one beamformer.
14A is a graph illustrating a first embodiment of an antenna gain and a beam pattern according to the embodiment shown in FIG. 13A.
14B is a graph illustrating a first embodiment of an antenna gain and a beam pattern according to the embodiment shown in FIG. 13B.
15 is a conceptual diagram illustrating a first embodiment of a beam pattern when hybrid beamforming is performed.
16 is a graph illustrating a first embodiment of an antenna gain and a beam pattern when hybrid beamforming is performed.
17A is a conceptual diagram illustrating a first embodiment of a panel-based beam transmission method.
17B is a conceptual diagram illustrating a second embodiment of a panel-based beam transmission method.
17C is a conceptual diagram illustrating a third embodiment of a panel-based beam transmission method.
17D is a conceptual diagram illustrating a fourth embodiment of a panel-based beam transmission method.
18A is a conceptual diagram illustrating a first embodiment of a method for transmitting a beam through a repeater.
18B is a conceptual diagram illustrating a second embodiment of a method for transmitting a beam through a repeater.
19 is a conceptual diagram illustrating a first embodiment of a beam pattern to which a virtual beam combining method is applied.
20 is a conceptual diagram illustrating a first embodiment of a beam combined through a virtual beam combining method.
21 is a graph illustrating a first embodiment of an antenna gain and a beam pattern in an embodiment to which panel virtualization is applied.
22 is a graph illustrating a first embodiment of an antenna gain and a beam pattern according to a beam combining method.
23 is a graph illustrating a search delay according to a beam search method.
24 is a conceptual diagram illustrating a first embodiment of a beam measurement procedure.
25 is a conceptual diagram illustrating a second embodiment of a beam measurement procedure.
26A is a timing diagram illustrating a first embodiment of a transmission method of a beam measurement signal.
26B is a timing diagram illustrating a second embodiment of a method of transmitting a beam measurement signal.
27 is a conceptual diagram illustrating a configuration of a beam measurement signal in an MRU.

Since the present invention can have various changes and can have various embodiments, specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the present invention to a specific embodiment, it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention.

Terms such as first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component. and/or includes a combination of a plurality of related listed items or any of a plurality of related listed items.

When a component is referred to as being “connected” or “connected” to another component, it may be directly connected or connected to the other component, but it is understood that other components may exist in between. it should be On the other hand, when it is said that a certain element is "directly connected" or "directly connected" to another element, it should be understood that the other element does not exist in the middle.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It is to be understood that this does not preclude the possibility of the presence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. does not

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings. In describing the present invention, in order to facilitate the overall understanding, the same reference numerals are used for the same components in the drawings, and duplicate descriptions of the same components are omitted.

A communication system to which embodiments according to the present invention are applied will be described. The communication system may be a 4G communication system (eg, a long-term evolution (LTE) communication system, an LTE-A communication system), a 5G communication system (eg, a new radio (NR) communication system), and the like. The 4G communication system may support communication in a frequency band of 6 GHz or less, and the 5G communication system may support communication in a frequency band of 6 GHz or more as well as a frequency band of 6 GHz or less. The communication system to which the embodiments according to the present invention are applied is not limited to the contents described below, and the embodiments according to the present invention can be applied to various communication systems. Here, a communication system may be used in the same meaning as a communication network (network).

1 is a conceptual diagram illustrating a first embodiment of a communication system.

1, the communication system 100 is a plurality of communication nodes (110-1, 110-2, 110-3, 120-1, 120-2, 130-1, 130-2, 130-3, 130-4, 130-5, 130-6). In addition, the communication system 100 is a core network (core network) (eg, S-GW (serving-gateway), P-GW (packet data network (PDN)-gateway), MME (mobility management entity)) may include more.

The plurality of communication nodes 110 to 130 may support a communication protocol (eg, an LTE communication protocol, an LTE-A communication protocol, an NR communication protocol, etc.) defined in a 3rd generation partnership project (3GPP) standard. The plurality of communication nodes 110 to 130 include a code division multiple access (CDMA) technology, a wideband CDMA (WCDMA) technology, a time division multiple access (TDMA) technology, a frequency division multiple access (FDMA) technology, orthogonal frequency division (OFDM). multiplexing) technology, Filtered OFDM technology, CP (cyclic prefix)-OFDM technology, DFT-s-OFDM (discrete Fourier transform-spread-OFDM) technology, OFDMA (orthogonal frequency division multiple access) technology, SC (single carrier)-FDMA Technology, Non-orthogonal Multiple Access (NOMA) technology, GFDM (generalized frequency division multiplexing) technology, FBMC (filter bank multi-carrier) technology, UFMC (universal filtered multi-carrier) technology, SDMA (Space Division Multiple Access) technology, etc. can support Each of the plurality of communication nodes may have the following structure.

2 is a block diagram showing a first embodiment of a communication node constituting a communication system.

Referring to FIG. 2 , the communication node 200 may include at least one processor 210 , a memory 220 , and a transceiver 230 connected to a network to perform communication. In addition, the communication node 200 may further include an input interface device 240 , an output interface device 250 , a storage device 260 , and the like. Each of the components included in the communication node 200 may be connected by a bus 270 to communicate with each other. However, each of the components included in the communication node 200 may not be connected to the common bus 270 but to the processor 210 through an individual interface or an individual bus. For example, the processor 210 may be connected to at least one of the memory 220 , the transceiver 230 , the input interface device 240 , the output interface device 250 , and the storage device 260 through a dedicated interface. .

The processor 210 may execute a program command stored in at least one of the memory 220 and the storage device 260 . The processor 210 may mean a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which methods according to embodiments of the present invention are performed. Each of the memory 220 and the storage device 260 may be configured as at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory 220 may be configured as at least one of a read only memory (ROM) and a random access memory (RAM).

Referring back to FIG. 1 , the communication system 100 includes a plurality of base stations 110 - 1 , 110 - 2 , 110 - 3 , 120 - 1 and 120 - 2 , and a plurality of terminals 130 - 1, 130-2, 130-3, 130-4, 130-5, 130-6). Each of the first base station 110-1, the second base station 110-2, and the third base station 110-3 may form a macro cell. Each of the fourth base station 120-1 and the fifth base station 120-2 may form a small cell. The fourth base station 120-1, the third terminal 130-3, and the fourth terminal 130-4 may belong to the cell coverage of the first base station 110-1. The second terminal 130-2, the fourth terminal 130-4, and the fifth terminal 130-5 may belong to the cell coverage of the second base station 110-2. The fifth base station 120-2, the fourth terminal 130-4, the fifth terminal 130-5, and the sixth terminal 130-6 may belong to the cell coverage of the third base station 110-3. have. The first terminal 130-1 may belong to the cell coverage of the fourth base station 120-1. The sixth terminal 130-6 may belong to the cell coverage of the fifth base station 120-2.

Here, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 is a NodeB (NB), an evolved NodeB (eNB), gNB, an advanced base station (ABS), HR - BS (high reliability-base station), BTS (base transceiver station), radio base station (radio base station), radio transceiver (radio transceiver), access point (access point), access node (node), RAS (radio access station) ), MMR-BS (mobile multihop relay-base station), RS (relay station), ARS (advanced relay station), HR-RS (high reliability-relay station), HNB (home NodeB), HeNB (home eNodeB), It may be referred to as a road side unit (RSU), a radio remote head (RRH), a transmission point (TP), a transmission and reception point (TRP), and the like.

Each of the plurality of terminals 130-1, 130-2, 130-3, 130-4, 130-5, 130-6 includes a user equipment (UE), a terminal equipment (TE), an advanced mobile station (AMS), HR-MS (high reliability-mobile station), terminal, access terminal, mobile terminal, station, subscriber station, mobile station, portable It may be referred to as a portable subscriber station, a node, a device, an on board unit (OBU), and the like.

Meanwhile, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may operate in different frequency bands or may operate in the same frequency band. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be connected to each other through an ideal backhaul link or a non-ideal backhaul link. , information can be exchanged with each other through an ideal backhaul link or a non-ideal backhaul link. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be connected to the core network through an ideal backhaul link or a non-ideal backhaul link. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 transmits a signal received from the core network to the corresponding terminals 130-1, 130-2, 130-3, 130 -4, 130-5, 130-6), and the signal received from the corresponding terminal (130-1, 130-2, 130-3, 130-4, 130-5, 130-6) is transmitted to the core network can be sent to

In addition, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 transmits MIMO (eg, single user (SU)-MIMO, multi user (MU)- MIMO, massive MIMO, etc.), coordinated multipoint (CoMP) transmission, carrier aggregation (CA) transmission, transmission in an unlicensed band, direct communication between terminals (device to device communication, D2D) (or , Proximity Services (ProSe)), Internet of Things (IoT) communication, dual connectivity (DC), and the like may be supported. Here, each of the plurality of terminals 130-1, 130-2, 130-3, 130-4, 130-5, 130-6 is the base station 110-1, 110-2, 110-3, and 120-1. , 120-2) and operations supported by the base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be performed. For example, the second base station 110-2 may transmit a signal to the fourth terminal 130-4 based on the SU-MIMO method, and the fourth terminal 130-4 may transmit a signal based on the SU-MIMO method. A signal may be received from the second base station 110 - 2 . Alternatively, the second base station 110-2 may transmit a signal to the fourth terminal 130-4 and the fifth terminal 130-5 based on the MU-MIMO scheme, and the fourth terminal 130-4. and each of the fifth terminals 130 - 5 may receive a signal from the second base station 110 - 2 by the MU-MIMO method.

Each of the first base station 110-1, the second base station 110-2, and the third base station 110-3 may transmit a signal to the fourth terminal 130-4 based on the CoMP method, and the fourth The terminal 130-4 may receive signals from the first base station 110-1, the second base station 110-2, and the third base station 110-3 by the CoMP method. A plurality of base stations (110-1, 110-2, 110-3, 120-1, 120-2) each of the terminals (130-1, 130-2, 130-3, 130-4) belonging to its own cell coverage , 130-5, 130-6) and the CA method can transmit and receive signals. Each of the first base station 110-1, the second base station 110-2, and the third base station 110-3 controls D2D between the fourth terminal 130-4 and the fifth terminal 130-5. and each of the fourth terminal 130-4 and the fifth terminal 130-5 may perform D2D under the control of the second base station 110-2 and the third base station 110-3, respectively. .

Meanwhile, in embodiments of the present invention, the device providing the improved communication service may be an enhanced Mobile Broadband (eMBB) device, a Low Latency enabled (LL) device, a Coverage Enhanced (CE) device, or a Low complexity (LC) device. The eMBB device may support the transmission/reception function of large-capacity data. The LL device may support the function of reducing transmission delay. The CE device may support a transmission distance enhancement function. The LC device may support a complexity improvement function. In the embodiments described below, a device (eg, an eMBB device, an LL device, a CE device, an LC device, etc.) providing an enhanced communication service may be referred to as an “S-device”.

The S-device is a device supporting a transmission function (eg, a base station in a downlink communication procedure, a terminal in an uplink communication procedure, etc.), a device supporting a reception function (eg, a terminal in a downlink communication procedure, an uplink communication procedure) In a link communication procedure, such as a base station), a device supporting a relay function (eg, a relay, etc.) may be used. In addition, the S-device may be located in a device having mobility (eg, a car, a train, an airplane, a drone, etc.).

The meanings of terms used in the embodiments below may be defined as follows.

- A _A : array antenna pattern (dB)

- A _E : composite array antenna pattern (dB)

- A _m : front-to-back ratio

: 방사 엘리먼트(radiation element)의 수평(horizontal) 패턴-

: horizontal pattern of radiation element

: 방사 엘리먼트의 수직(vertical) 방사 패턴(예를 들어, 어레이 안테나와 수직인 점과 90도의 오프셋(offset by 90° to point to perpendicular to array)을 가지는 방사 엘리먼트의 수직 방사 패턴)-

: a vertical radiation pattern of a radiating element (eg, a vertical radiation pattern of a radiating element having an offset by 90° to point to perpendicular to array)

: RF(radio frequency) 체인(chain)에 의한 수평 커버 디그리(horizontal covered degree)-

: Horizontal covered degree by RF (radio frequency) chain

: RF 체인(chain)에 의한 수직 커버 디그리(vertical covered degree)-

: Vertical covered degree by RF chain

: 수평 방향에서 패널들(panels) 간의 거리-

: distance between panels in the horizontal direction

: 수직 방향에서 패널들 간의 거리-

: Distance between panels in vertical direction

: 섹터(sector)의 수평 커버 디그리-

: Horizontal cover degree of sector

: 섹터의 수직 커버 디그리-

: vertical cover degree of sector

: 수평 방향에서 송신기(transmitter)의 안테나 엘리먼트들 간의 거리-

: Distance between antenna elements of a transmitter in the horizontal direction

: 수직 방향에서 송신기의 안테나 엘리먼트들 간의 거리-

: the distance between the antenna elements of the transmitter in the vertical direction

: m번째 열(column)과 n번째 행(row)에서 방사 엘리먼트의 복소 이득(complex gain)(예를 들어, 어레이 안테나 배치에 따른 위상 시프트(shift)를 가지는 복소 이득)-

: Complex gain of the radiating element in the m-th column and n-th row (eg, complex gain with phase shift according to the array antenna arrangement)

: 방사 엘리먼트의 최대 방향성 이득(dB), 예를 들어, 최대 방향성 이득은 8dBi일 수 있음.-

: The maximum directional gain (dB) of the radiating element, for example, the maximum directional gain may be 8 dBi.

: 방위각(azimuth angle)(예를 들어, 수평축)에서 수평 섹터들의 개수-

: number of horizontal sectors in azimuth angle (eg, horizontal axis)

: 천정각(zenith angle)(예를 들어, 수직축)에서 수직 섹터들의 개수-

: number of vertical sectors at zenith angle (eg vertical axis)

: 하나의 송신기에 의해 제공되는(served) 섹터들의 개수-

: Number of sectors served by one transmitter

: 빔포머(beamformer) 내의 패널들의 개수-

: the number of panels in the beamformer

: 빔포머 내의 수평 방향(행)에서 패널들의 개수 (>0)-

: Number of panels in the horizontal direction (row) in the beamformer (>0)

: 빔포머 내의 수직 방향(열)에서 패널들의 개수 (>0)-

: Number of panels in the vertical direction (column) in the beamformer (>0)

: RF 체인에 의해 사용 가능한 빔들의 개수-

: Number of beams usable by the RF chain

: 수평 방향에서 RF 체인에 의해 사용 가능한 빔들의 개수-

: Number of beams usable by the RF chain in the horizontal direction

: 수직 방향에서 RF 체인에 의해 사용 가능한 빔들의 개수-

: Number of beams usable by the RF chain in the vertical direction

: 수신기(receiver)의 RF 체인(예를 들어, 하나의 패널 내의 RF 체인)에 의해 연결되는 안테나 엘리먼트들의 개수-

: The number of antenna elements connected by an RF chain of a receiver (eg, an RF chain in one panel)

: 수신기의 하나의 패널 내의 수평 방향의 안테나 엘리먼트들의 개수 (>0) -

: The number of antenna elements in the horizontal direction in one panel of the receiver (>0)

: 수신기의 하나의 패널 내의 수직 방향의 안테나 엘리먼트들의 개수 (>0)-

: The number of antenna elements in the vertical direction in one panel of the receiver (>0)

: 송신기의 RF 체인(예를 들어, 하나의 패널 내의 RF 체인)에 의해 연결되는 안테나 엘리먼트들의 개수-

: the number of antenna elements connected by the RF chain of the transmitter (eg, the RF chain in one panel)

: 송신기의 하나의 패널 내의 수평 방향의 안테나 엘리먼트들의 개수 (>0) -

: The number of antenna elements in the horizontal direction in one panel of the transmitter (>0)

: 송신기의 하나의 패널 내의 수직 방향의 안테나 엘리먼트들의 개수 (>0)-

: The number of antenna elements in the vertical direction in one panel of the transmitter (>0)

: 엘리먼트 패턴의 크기(magnitude)-

: Size of element pattern (magnitude)

: 사이드-로브(side-lobe) 레벨 제한-

: side-lobe level limit

: 방위각(예를 들어, 방위각은 -180° 내지 180° 사이에서 정의됨)-

: azimuth (eg, azimuth is defined between -180° and 180°)

: 한 방향의 고도각(elevation angle)(예를 들어, 고도각은 0° 내지 180° 사이에서 정의되고, 90°는 어레이 안테나에 수직인 것을 지시함)-

: Elevation angle in one direction (eg, elevation angle is defined between 0° and 180°, 90° indicates perpendicular to the array antenna)

: 송신기에서 안테나의 수직 3dB 빔폭(beamwidth)-

: Vertical 3dB beamwidth of the antenna at the transmitter

: 송신기에서 안테나의 수평 3dB 빔폭-

: Horizontal 3dB beamwidth of the antenna at the transmitter

: 동작 캐리어 주파수에 대응하는 파장-

: Wavelength corresponding to the operating carrier frequency

: 신호 상관 계수(signal correlation coefficient)-

: signal correlation coefficient

■ How to provide improved communication services

In order to provide an improved communication service (eg, a communication service supporting transmission of large data, a communication service supporting a high data rate, etc.) according to a user's request, at least one of the following methods may be used.

- Method 1: Increase the transmission rate

- Method 2: Improve spectral efficiency

- Method 3: Provide system bandwidth to meet service needs

- Method 4: Provide a connection that meets your service needs

- Method 5: Retransmission to improve reliability, avoid retransmission through improved transmission procedure

- Method 6: Provide wide coverage

- Method 7: Transmission considering operating frequency characteristics

Better transfer rate

The transmission rate may be improved through improved signal processing. When there is a frequency operation regulation according to spectrum use, a communication service may be provided within a range that satisfies the frequency operation regulation. For example, when transmission based on a high modulation and coding scheme (MCS) level (eg, 1024 quadrature amplitude modulation (QAM)) is performed, transmission capacity may be increased. However, the wireless signal may experience loss of free space, loss due to an environment (eg, rain, air, etc.). In particular, in a frequency band of 6 GHz or higher (hereinafter, referred to as “mmWave band”), it may be necessary to consider loss according to an environment (eg, rain, air, etc.).

Therefore, in order to use a high MCS level in the mmWave band, the MCS level may be adaptively adjusted according to an environment (eg, rain, air, etc.). For example, whether link adaptation is performed based on the likelihood of rainfall (eg 99.5%, 99.9%, 99.95%, 99.99%, 99.995%, 99.999%, etc.) based on a specific time period (eg period). , an MCS level (eg, a maximum available MCS level) may be set.

A communication service may be provided by combining two or more radio links similarly to a carrier aggregation scheme. For example, a communication service may be provided by combining a low-frequency link (eg, a microwave link of 6 GHz or less) and a high-frequency link (eg, a mmWave link of 6 GHz or more). In this case, radio links may be combined in consideration of channel characteristics of each of the low-frequency link and the high-frequency link. Also, when the quality of one radio link (eg, a high-frequency link) deteriorates, a communication service may be provided using another radio link (eg, a low-frequency link). For example, among the combined radio links, a radio link that is robust to changes in the environment may be used, and a radio link selected based on the transmission distance of the signal (eg, a low-frequency link in the case of long-distance transmission) may be used.

Improved spectral efficiency

Spectral efficiency can be improved through multiplexing. Multiplexing may be performed through a plurality of layers/links. For example, multiplexing may be performed through multiple antennas or multiple transmission points. Proper placement of multiple antennas (eg, spacing between antennas) to form multiple layers/links for multiplexing may be required. In addition, control/cooperation between transmission points may be required for multiplexing. Alternatively, the quality of the received signal may be improved through appropriate combining of the received signal according to the difference between the plurality of paths.

Provide suitable system bandwidth

A wide system bandwidth may be required for the transmission of large amounts of data. A wide system bandwidth can be provided by combining a plurality of radio links. A large amount of data can be transmitted over a wide system bandwidth in an unlicensed/public frequency band. However, the maximum system bandwidth may be limited to 1-2 GHz or less due to hardware limitations of communication nodes (eg, base stations, terminals, and S-devices). For coexistence between communication systems or coexistence between communication nodes, the system bandwidth may be partitioned.

Provides many connections

In the communication system, point-to-point (P2P) communication, point-to-multipoint (P2MP) communication, etc. may be supported, and in this case, many connections may be supported through limited radio resources.

Improved reliability

Data may not be transmitted successfully due to the characteristics of the wireless channel. In order to solve this problem, a robust and reliable transmission procedure, a data transmission error correction procedure, data retransmission procedure, etc. may be performed. The transmitter may transmit data to the receiver, the receiver may transmit a response (eg, acknowledgment (ACK), negative ACK (NACK)) to the data obtained from the transmitter, and the transmitter may transmit a response received from the receiver It is possible to determine whether to perform the data retransmission procedure based on the . Alternatively, for reliability improvement, the transmitter may retransmit the same data without a response (eg, ACK or NACK). Reliability may be improved as data is transmitted through a plurality of links or a plurality of transmission points.

coverage expansion

To provide wide coverage, a transmitter may transmit a signal using a high transmit power. As the transmission distance increases, the received signal strength may decrease, and the receiver may provide wide coverage by processing a signal having a low received signal strength. The coverage may be extended through multi-hop transmission by a repeater. Coverage can be extended by transmitting a signal in a specific direction using high transmit power. In this case, a directional antenna (eg, a directional antenna) may be used, and a plurality of antennas may be disposed to transmit a signal in a specific direction. In addition, communication performance may be improved by applying an interference cancellation technique.

■ Communication method based on multiple antennas

Next, a method for improving spectral efficiency based on multiple antennas, a method for extending coverage, and the like will be described.

Beamforming ( beamforming )

Beamforming may be performed through a directional antenna, antenna arrangement, beam radiation, and the like. Through beamforming, coverage for a specific direction may be extended. However, for a receiver having mobility, beamforming may be performed in all directions. In addition, when the position of the receiver is not accurately predicted, communication performance according to beamforming may be deteriorated. In order to solve this problem, beamforming may be performed in all directions.

3 is a conceptual diagram illustrating a first embodiment of a beamforming-based transmission method.

Referring to FIG. 3 , a communication node (eg, a base station, a terminal, an S-device, etc.) may independently perform beamforming in each of the sectors. When the communication node includes one antenna, the communication node may perform beamforming in each of the sectors (eg, sectors #0 to #7) using one antenna. Alternatively, when the communication node includes a plurality of antennas, the communication node may simultaneously perform beamforming in a plurality of sectors (eg, sectors #0 to #7) using the plurality of antennas.

4 is a conceptual diagram illustrating a first embodiment of an antenna module.

Referring to FIG. 4 , in order to provide a communication service in each of the sectors (eg, sector #0 to sector #7 shown in FIG. 3 ), the antenna module 400 includes a plurality of beamformers (eg, 18 beamformers 410 - 1 to 410 - 18 ). One beamformer may be disposed on one surface of the antenna module 400 . For example, beamformers #2 to #6 (410-2 to 410-6) may be disposed on planes positioned on the beamformer #1 (410-1) and the horizontal axis (eg, the axis horizontal to the xy plane). and beamformers #7 to #12 (410-7 to 410-12) on the surfaces above the plane on which the beamformer #1 (410-1) is disposed with respect to a vertical axis (eg, an axis perpendicular to the xy plane). ) may be disposed, and beamformers #13 to #18 (410-13) on the surfaces below the plane on which the beamformer #1 (410-1) is disposed with respect to a vertical axis (eg, an axis perpendicular to the xy plane). to 410-18) may be disposed. One beamformer may form at least one beam and may be mapped to one sector. For example, one beamformer may provide a communication service in one sector.

Each of the beamformers 410-1 to 410-18 may include at least one panel (eg, an antenna panel), and one panel may include at least one array antenna, and the array antenna may include: It may include at least one antenna element. The arrangement of the panel, the array antenna, and the antenna element may be the same in all the beamformers 410 - 1 to 410 - 18 included in the antenna module 400 . Alternatively, the arrangement of the panel, the array antenna, and the antenna element may be independent in each of the beamformers 410 - 1 to 410 - 18 . For example, beamformer #1 (410-1) may include four panels (410-1-1 to 410-1-4), and panel #1-1 (410-1-1) is It may include two array antennas 410-1-1-1 and 410-1-1-2, and the array antenna #1-1-1 (410-1-1-1) has 24 antenna elements. may include

Meanwhile, a beamformer disposed on a horizontal axis may be referred to as a “horizontal beamformer”, and N _h horizontal beamformers may be disposed in the antenna module according to embodiments of the present invention. The N _h horizontal beamformers may be used for communication with a communication node (eg, a base station, a terminal, an S-device, etc.) located at the same or similar height. A beamformer disposed on the vertical axis may be referred to as a “vertical beamformer”, and N _v vertical beamformers may be disposed in the antenna module according to embodiments of the present invention. N _v vertical beamformers may be used for communication with communication nodes (eg, base stations, terminals, S-devices, etc.) located at different heights. Each of N _h and N _v may be an integer of 1 or more.

When the area in which the antenna module provides communication service (hereinafter referred to as "service area") is a sphere, the angle of the horizontal sector in which one horizontal beamformer provides communication service in the horizontal axis may be "2π/N _h ", and , an angle of a vertical sector in which one vertical beamformer provides a communication service on the vertical axis may be "π/N _v ". For example, when the reference point is 0°, the coordinates (eg, angle) of the horizontal sector may be defined based on Equation 1 below, and the coordinates (eg, angle) of the vertical sector may be determined by the equation below. 2 can be defined.

5A is a conceptual diagram illustrating a first embodiment of a horizontal sector in a service area, FIG. 5B is a conceptual diagram illustrating a first embodiment of a vertical sector in a service area, and FIG. 5C is a first embodiment of a sector configuration in a service area It is a conceptual diagram showing an example.

5A to 5C , three horizontal sectors may exist in a service area, and three vertical sectors may exist in a service area. According to a combination of three horizontal sectors and three vertical sectors, nine sectors may exist in the service area.

Meanwhile, a plurality of beamformers may provide a communication service in one sector. Alternatively, one beamformer may provide a communication service in a plurality of sectors. When a beam is distinguished within one sector, if a beam change is required due to movement of the terminal, the corresponding beam may be changed without changing the sector.

6 is a conceptual diagram illustrating a second embodiment of a sector configuration in a service area.

Referring to FIG. 6 , an inner sector and an outer sector may be set for the service area according to the transmission distance of the base station 600 . A separate beamformer may be operated for each of the inner sector and the outer sector.

7 is a conceptual diagram illustrating a third embodiment of a sector configuration in a service area.

Referring to FIG. 7 , the service area may be divided into a lower sector, a middle sector, and an upper sector according to a height of a receiver (eg, a terminal). The base station 700 may provide communication services in each of the lower sector, the middle sector, and the upper sector.

8 is a conceptual diagram illustrating a fourth embodiment of a sector configuration in a service area.

Referring to FIG. 8 , when a plurality of beamformers (eg, beamformers #1 and #2) belonging to an antenna module of a transmitter provide a communication service to one sector, a plurality of beamformers within one sector Beam identification (ID) for uniquely distinguishing each of beams (eg, beams #11 to #14, beams #21 to #24) generated by formers (eg, beamformers #1 and #2) ) can be set.

Alternatively, a beam ID for uniquely distinguishing each of the beams in one beamformer (eg, a sub-sector supported by one beamformer may be set. For example, in sub-sector #1 A beam ID for uniquely discriminating each of beams #11 to #14 may be set, and a beam ID for uniquely discriminating each of beams #21 to #24 in sub-sector #2 may be set. In this case, beams between beamformers (eg, beamformers #1 and #2) may be distinguished according to a sub-sector supported by the beamformer.

9 is a conceptual diagram illustrating a first embodiment of a panel in a beamformer.

Referring to FIG. 9 , the beamformer may include a plurality of panels, and the plurality of panels may be independently disposed. Each of the plurality of panels may generate an independent beam and may provide communication services in different service areas. A plurality of service areas for each panel may be operated as follows. Here, "service area" may indicate "sector", and "sub-service area" may indicate "sub-sector".

- Operation method 1: A service area served by one beamformer is divided into sub-service areas independently served by each of the panels belonging to one beamformer.

- Operation method 2: One service area served by panels belonging to one beamformer is set.

When the service area served by the beamformer is set to the service area (eg, 2π/N _h , π/N _v ) shown in FIGS. 5A to 5C , the corresponding service area is the service area served by the panel. (eg, "service area of one beamformer = service area of one panel") or service area served by each of the panels (eg, "service area of one beamformer/service area of one panel") service area") can be set/operated.

Meanwhile, the antenna elements in the panel may be spatially independently disposed, and a beam may be generated by the antenna elements disposed in one panel. By adjusting the spacing (d _g,H , d _g,V ) between the panels, the beams of each of the panels can be independently generated. Alternatively, a communication service may be provided through a combined beam between the panels by adjusting the intervals d _g,H , d _g,V between the panels. In this case, the arrangement of antenna elements in the panels may be the same.

개의 패널들이 배치될 수 있고, 하나의 빔포머의 수직축에서

개의 패널들이 배치될 수 있다. 즉, 하나의 빔포머는

개의 패널들을 포함할 수 있다. 하나의 패널은 적어도 하나의 RF 체인과 연결될 수 있다. 이 경우, RF는 패널을 지칭할 수 있다. 하나의 패널의 수평축에서

개의 안테나 엘리먼트들이 배치될 수 있고, 하나의 패널의 수직축에서

개의 안테나 엘리먼트들이 배치될 수 있다. 즉, 하나의 패널은

개의 안테나 엘리먼트들을 포함할 수 있다. 인접한 패널들 간의 수평축 간격은 d_g,H일 수 있고, 인접한 패널들 간의 수직축 간격은 d_g,V일 수 있다. 인접한 안테나 엘리먼트들 간의 수평축 간격은

일 수 있고, 인접한 안테나 엘리먼트들 간의 수직축 간격은

일 수 있다. 전송률 향상을 위해 패널은 편파(polarisation)될 수 있다.

_max는 패널들 각각의 최대 수직 틸팅(tilting) 각도(예를 들어, 다운틸팅 각도, 업틸팅 각도)를 지시할 수 있다. 예를 들어,

_max는 102°일 수 있다.

_max는 패널들 각각의 최대 수평 틸팅 각도를 지시할 수 있다.in the horizontal axis of one beamformer

Panels can be arranged, in the vertical axis of one beamformer

Four panels may be placed. That is, one beamformer

It may include four panels. One panel may be connected to at least one RF chain. In this case, RF may refer to a panel. on the horizontal axis of one panel

Antenna elements can be arranged, in the vertical axis of one panel

Antenna elements may be disposed. That is, one panel

It may include antenna elements. A horizontal interval between adjacent panels may be d _g,H , and a vertical interval between adjacent panels may be d _g,V . The horizontal spacing between adjacent antenna elements is

may be, the vertical axis spacing between adjacent antenna elements is

can be The panel can be polarized to improve the transmission rate.

_max may indicate a maximum vertical tilting angle (eg, a downtilting angle, an uptilting angle) of each of the panels. for example,

_max may be 102°.

_max may indicate the maximum horizontal tilting angle of each of the panels.

Meanwhile, in embodiments of the present invention, the beamwidth may be a “half-power beamwidth (HPBW)” having an intensity of 1/2 compared to a main lobe. The antenna module may generate a radiation pattern based on Table 1 below.

10 is a conceptual diagram illustrating a first embodiment of a 2D uniform rectangular array (URA) antenna disposed in a panel.

개의 안테나 엘리먼트들이 배치될 수 있고, 2D URA 안테나의 수직축(예를 들어, xy 평면과 수직인 축)에서

개의 안테나 엘리먼트들이 배치될 수 있다. 인접한 안테나 엘리먼트들 간의 수평 간격은 d_H일 수 있고, 인접한 안테나 엘리먼트들 간의 수직 간격은 d_V일 수 있다.Referring to FIG. 10 , in a horizontal axis (eg, an axis horizontal to the xy plane) of the 2D URA antenna.

Antenna elements may be disposed, in a vertical axis (eg, an axis perpendicular to the xy plane) of the 2D URA antenna.

Antenna elements may be disposed. A horizontal spacing between adjacent antenna elements may be d _H , and a vertical spacing between adjacent antenna elements may be d _V.

)가 적용될 수 있다. 2D URA 안테나에서 안테나 엘리먼트의 배치에 따라 아래 수학식 3에 따른 위상 변위가 ABF(analog beamforming)에 적용될 수 있다.Depending on the arrangement of the antenna elements, the array factor (

) can be applied. A phase shift according to Equation 3 below may be applied to analog beamforming (ABF) according to the arrangement of antenna elements in the 2D URA antenna.

(예를 들어, 0 <

)로 스티어링될 수 있고, 수직축에서 안테나 모듈(예를 들어, 안테나 모듈에 속한 패널, 어레이 안테나, 안테나 엘리먼트)은 지향점을 기준으로 수직축으로 최대

(예를 들어,

≤ π/2}로 스티어링될 수 있다.In the horizontal axis, an antenna module (eg, a panel belonging to an antenna module, an array antenna, an antenna element) is the maximum with respect to the boresight.

(e.g. 0 <

), and in the vertical axis, an antenna module (eg, a panel belonging to an antenna module, an array antenna, an antenna element) has a maximum in the vertical axis with respect to the direction point.

(for example,

≤ π/2}.

Meanwhile, when electrical tilting is applied, a baseband signal may be processed based on Equation 4 below.

Meanwhile, an antenna gain and a beam width according to beamforming may be as follows.

11 is a graph illustrating a first embodiment of an antenna gain and a beam pattern according to beamforming.

Referring to FIG. 11 , “1×1”, “2×2”, “4×4”, “8×8”, “16×16”, and “32×32” are antenna elements that perform beamforming, respectively. You can indicate the number of them. Beamforming may be performed through alignment of a plurality of antenna elements in order to improve a transmission rate. As the number of antenna elements used for beamforming increases, an antenna gain may increase and a beamwidth may decrease. Therefore, a beam pattern for beamforming may be required, and a beam tracking procedure may be required for rapid device/beam discovery, efficient antenna alignment, and data transmission/reception procedure.

Meanwhile, a data transmission/reception procedure according to beamforming may be performed based on the following beamforming operation state transition diagram.

12 is a conceptual diagram illustrating a first embodiment of a beamforming operation state transition diagram.

Referring to FIG. 12 , a beam may be obtained by searching for a beam (eg, a panel) in a beam sweeping state. For example, a beam may be acquired through a beam search in an initial access procedure, a handover (HO) procedure, a radio link failure (RLF) recovery procedure, and the like. A beam refinement procedure for maintaining a link in a beam tracking state (eg, maintaining a data transmission/reception procedure) may be performed.

For the data transmission/reception procedure based on beamforming, the receiver performs a beam measurement procedure, a beam identification procedure (eg, a beam search procedure), a precoder selection procedure, a link adaptation procedure, a hybrid automatic repeat request (HARQ) retransmission. For example, a channel measurement procedure, an interference measurement procedure, and the like may be performed. For a data transmission/reception procedure based on beamforming, the transmitter may perform beam selection/reselection/change/allocation/cancellation operations based on a measurement result obtained from the receiver. Operations performed in the transmitter may be performed in a beam sweeping state or a beam tracking state.

Meanwhile, in a communication system to which hybrid beamforming is applied, a system model may be defined based on Equations 5 to 8 below according to antenna modeling and arrangement.

In Equation 6, R may be an array correlation matrix, and R may be defined based on Equation 7 below.

는 i번째 열과 j번째 행에서 신호들 간의 상관일 수 있고, 공간적으로 상관되는 안테나 엘리먼트들 간의 패스트 페이딩(fast fading)으로 추정될 수 있다. 또한, 수학식 7은 아래 수학식 8과 같이 간소화될 수 있다.in Equation 7

may be a correlation between signals in an i-th column and a j-th row, and may be estimated as fast fading between spatially correlated antenna elements. In addition, Equation 7 can be simplified as Equation 8 below.

When hybrid beamforming is performed, a beam may be generated at an analog end and a digital end. The beam pattern may be set based on a combination of a beam pattern of at least one of an analog end and a digital end. Here, the analog stage may be a component located before an analog-to-digital converter (ADC) among components of a communication node (eg, a base station, a terminal, an S-device, etc.), and the beam of the analog stage is an analog It could be a signal. The digital stage may be a component located after the ADC among components of the communication node, and the beam of the digital stage may be a digital signal.

■ Analog beam pattern

One beamformer included in the antenna module may correspond to one sector, and the beamformer may include a plurality of panels (eg, array antennas and antenna elements) that perform beamforming.

13A is a conceptual diagram illustrating a first embodiment of a beam pattern in a service area served by one beamformer, and FIG. 13B illustrates a second embodiment of a beam pattern in a service area served by one beamformer. It is a conceptual diagram.

13A and 13B, A _sector may indicate a service area served by a beamformer or a corresponding beamformer, and A _RF may indicate a service area served by a panel in the beamformer or the corresponding panel. have. A _sector may be defined based on Equation 9 below.

는 하나의 빔포머에 의해 서빙되는 수평 영역일 수 있고,

는 하나의 빔포머에 의해 서빙되는 수직 영역일 수 있다. A_RF는 아래 수학식 10에 기초하여 정의될 수 있다.In Equation 9,

may be a horizontal area served by one beamformer,

may be a vertical region served by one beamformer. A _RF may be defined based on Equation 10 below.

는 하나의 패널에 의해 서빙되는 수평 영역일 수 있고,

는 하나의 패널에 의해 서빙되는 수직 영역일 수 있다. A_beam은 아래 수학식 11에 기초하여 정의될 수 있다.In Equation 10,

may be a horizontal area served by one panel,

may be a vertical area served by one panel. A _beam may be defined based on Equation 11 below.

는 수평축으로 배치된 안테나 엘리먼트들에 의해 생성되는 HPBW일 수 있고,

는 수직축으로 배치된 안테나 엘리먼트들에 의해 생성되는 HPBW일 수 있다.

may be HPBW generated by antenna elements arranged in the horizontal axis,

may be HPBW generated by antenna elements arranged in a vertical axis.

If the following Equation 12 is satisfied, A _sector may be defined based on Equation 13 below, A _RF may be defined based on Equation 14 below, and A _beam is based on Equation 15 below. can be defined as

,

)는 아래 수학식 16에 기초하여 결정될 수 있다.The number of beams (

,

) may be determined based on Equation 16 below.

는 수평축에서 빔들의 개수일 수 있고,

는 수직축에서 빔들의 개수일 수 있다.

는 안테나 엘리먼트(또는, 패널, 어레이 안테나)의 최대 스티어링 수평축 각도일 수 있고,

는 안테나 엘리먼트(또는, 패널, 어레이 안테나)의 최대 스티어링 수직축 각도일 수 있다. 패널의 지향점은 "

/2,

/2"에 대응하는 좌표로 설정될 수 있다.

은 아래 수학식 17에 기초하여 정의될 수 있고,

은 아래 수학식 18에 기초하여 정의될 수 있다.

may be the number of beams in the horizontal axis,

may be the number of beams in the vertical axis.

may be the maximum steering horizontal axis angle of the antenna element (or panel, array antenna),

may be the maximum steering vertical axis angle of the antenna element (or panel, array antenna). The direction of the panel is "

/2,

It can be set to a coordinate corresponding to /2".

can be defined based on Equation 17 below,

may be defined based on Equation 18 below.

는 아래 수학식 20에 기초하여 정의될 수 있고,

는 아래 수학식 21에 기초하여 정의될 수 있다.If Equation 19 below is satisfied,

can be defined based on Equation 20 below,

may be defined based on Equation 21 below.

는 아래 수학식 22에 기초하여 정의될 수 있고,

는 아래 수학식 23에 기초하여 정의될 수 있다.In addition,

can be defined based on Equation 22 below,

may be defined based on Equation 23 below.

는 수평축에서 섹터들의 개수일 수 있고,

는 수직축에서 섹터들의 개수일 수 있다. "

×

"개의 섹터들이 존재할 수 있다.

는 수평축에서 패널들의 개수일 수 있고,

는 수직축에서 패널들의 개수일 수 있다. 하나의 빔포머 내에 "

×

"개의 패널들이 존재할 수 있다. 여기서,

,

,

및

각각은 1 이상의 정수일 수 있다. 또한, 아래 수학식 24가 정의될 수 있다.

may be the number of sectors in the horizontal axis,

may be the number of sectors on the vertical axis. "

×

“There may be n sectors.

may be the number of panels on the horizontal axis,

may be the number of panels on the vertical axis. in one beamformer

×

“There may be panels of

,

,

and

Each may be an integer of 1 or more. Also, Equation 24 below may be defined.

The coordinates of the (i _h , i _v ) beams of the (j _h , j _v ) panel arranged at equal intervals within the service area according to the beam pattern and the number of beams (eg, steering angle) are in Equation 25 below. can be defined based on In Equation 25, "Alt1" may be a first embodiment of a beam pattern in a service area served by one beamformer shown in FIG. 13A, and "Alt2" is a beamformer shown in FIG. 13B. It may be a second embodiment of a beam pattern in a served service area.

Meanwhile, when the sector is set to 60°×60° in FIG. 13A , the beam pattern and the directing point may be defined based on Table 2 below. In Table 2, "1 RF" may indicate one panel.

When a sector is set to 90°×90° in FIG. 13A , a beam pattern and a directing point may be defined based on Table 3 below. In Table 3, "1 RF" may indicate one panel.

Meanwhile, when the sector is set to 60°×60° in FIG. 13B , the beam pattern and the directing point may be defined based on Table 4 below. In Table 4, "1 RF" may indicate one panel.

When a sector is set to 90°×90° in FIG. 13B , a beam pattern and a directing point may be defined based on Table 5 below. In Table 5, "1 RF" may indicate one panel.

Meanwhile, in the embodiments shown in FIGS. 13A and 13B , the antenna gain and the beamwidth may be as follows.

14A is a graph illustrating a first embodiment of an antenna gain and beam pattern according to the embodiment shown in FIG. 13A , and FIG. 14B is a first embodiment of an antenna gain and beam pattern according to the embodiment shown in FIG. 13B . is a graph showing

14A and 14B , each of “2×2”, “4×4”, “8×8” and “16×16” may indicate the number of antenna elements, and RF indicates the panel. can In FIG. 14A , a communication service may be provided in the entire sector by one beamformer. In FIG. 14B , a communication service may be provided in a sector (eg, a partial area within a sector) by one panel. In this case, regions (eg, sub-sectors) in a sector corresponding to each of the panels belonging to one beamformer may be set, and each panel may provide a communication service in the corresponding sub-sector. . According to the embodiment of FIG. 14A , a coverage hole through which a communication service is not provided may be generated, and a beam pattern may be additionally generated to solve this problem. Alternatively, a beam may be generated at the digital stage to solve the coverage hole.

■ Analog Beam Codebook

는 양자화된 빔 스티어링 각도에 따른 {

,

}에 매핑되는 빔포밍 벡터일 수 있고, 송신기와 수신기에서 공유되는 아날로그 빔을 지시할 수 있다. 아날로그 빔 코드북(

)은 다음과 같이 정의될 수 있다.

is { according to the quantized beam steering angle {

,

} may be a beamforming vector mapped to }, and may indicate an analog beam shared by a transmitter and a receiver. Analog Beam Codebook (

) can be defined as

는 수학식 27 또는 수학식 28에 기초하여 빔 패턴(예를 들어, 빔폭, 지향점)의 서비스 영역의 각도에 따라 양자화될 수 있다. 수학식 27 및 수학식 28에서,

_max 및

_max 각각은

및

에 대응할 수 있다.

may be quantized according to the angle of the service area of the beam pattern (eg, beam width, directing point) based on Equation 27 or Equation 28. In Equation 27 and Equation 28,

_max and

_max each

and

can respond to

■ Digital beam pattern

A beam generated through a phase shift in the analog stage may be operated based on a beam width, a service area, and the like. However, when a coverage hole occurs between analog beams, detailed beamforming may be required. To solve this problem, digital beamforming (eg, digital beamforming (DBF), baseband precoding (BBP)) may be applied.

15 is a conceptual diagram illustrating a first embodiment of a beam pattern when hybrid beamforming is performed.

₁,

₂,

₃,

₄}을 가지는 4개의 빔들에 대한 빔 패턴에 전기적 틸팅(예를 들어,

_e)이 적용된 4개의 빔들에 대한 빔 패턴이 추가될 수 있다. 이 경우, 지향점 {

₁,

₁+

_e,

₂,

₂+

_e,

₃,

₃+

_e,

₄,

₄+

_e}을 가지는 8개의 빔들에 대한 빔 패턴이 생성될 수 있다. 전기적 틸팅에 기초하여 생성된 빔 패턴(예를 들어, 디지털 빔 패턴)의 성능은 지향점 {

₁+

_e,

₁+0,

₂+

_e,

₂+0,

₃+

_e,

₃+0,

₄+

_e,

₄+0}을 가지는 아날로그 빔 패턴의 성능과 동일할 수 있다. 빔 패턴은 아래 수학식 29에 기초하여 생성될 수 있다.Referring to Figure 15, the direction point {

₁ ,

₂ ,

₃ ,

Electrical tilting in the beam pattern for 4 beams with ₄ } (eg,

The beam pattern for the four beams to which _e ) is applied may be added. In this case, the orientation point {

₁ ,

₁ +

_e ,

₂ ,

₂₊

_e ,

₃ ,

₃ +

_e ,

₄ ,

₄ +

A beam pattern for 8 beams having _e } may be generated. The performance of a beam pattern (eg, a digital beam pattern) generated based on electrical tilting is determined by the directing point {

₁ +

_e ,

₁ +0,

₂₊

_e ,

₂ +0,

₃ +

_e ,

₃ +0,

₄ +

_e ,

It may be the same as the performance of the analog beam pattern having ₄ + 0}. The beam pattern may be generated based on Equation 29 below.

_i 및

_i는 빔의 지향점일 수 있다.An array factor for electrical tilting may be set based on Equation 30 below. here,

_i and

_i may be the directing point of the beam.

An interval between panels in one beamformer may be defined based on Equation 31 below.

16 is a graph illustrating a first embodiment of an antenna gain and a beam pattern when hybrid beamforming is performed.

Referring to FIG. 16 , electrical tilting is applied to a 4×4 fixed beam pattern (eg, a 4×4 analog beam pattern) in the digital stage, thereby forming an 8×8 beam pattern (eg, a “4×4 fixed beam pattern”). " + "4x4 electrically tilted beam pattern") can be generated. Each of the beam pattern and antenna gain of the embodiment shown in FIG. 16 may be the same as the beam pattern and antenna gain of the embodiment shown in FIG. 14B .

■ Digital Beam Codebook

는 양자화된 빔 스티어링 각도에 따른 {

,

}에 매핑되는 빔포밍 벡터일 수 있고, 송신기와 수신기에서 공유되는 디지털 빔을 지시할 수 있다. 디지털 빔 코드북(

)은 다음과 같이 정의될 수 있다.

is { according to the quantized beam steering angle {

,

} may be a beamforming vector mapped to }, and may indicate a digital beam shared by a transmitter and a receiver. Digital Beam Codebook (

) can be defined as follows.

는 수학식 33에 기초하여 빔 패턴(예를 들어, 빔폭, 지향점)의 서비스 영역의 각도에 따라 양자화될 수 있다.

may be quantized according to the angle of the service area of the beam pattern (eg, beam width, directing point) based on Equation 33.

■ Panel-based beam bonding

An independent RF (eg, beam) may be generated for each panel, and the same number of beams as the maximum number of panels may be used in a data transmission/reception procedure.

17A is a conceptual diagram illustrating a first embodiment of a panel-based beam transmission method, FIG. 17B is a conceptual diagram illustrating a second embodiment of a panel-based beam transmission method, and FIG. 17C is a panel-based beam transmission method It is a conceptual diagram illustrating a third embodiment, and FIG. 17D is a conceptual diagram illustrating a fourth embodiment of a panel-based beam transmission method.

In FIG. 17A , the base station 170 may provide communication services to the terminals 171-1 and 171-2 by transmitting different beams (eg, beams having different beam indexes) through a plurality of panels. and beams may be transmitted through different spaces. When the terminals 171-1 and 171-2 are located adjacent to each other, the base station 170 in FIGS. 17B to 17D communicates with the terminals 171-1 and 171-2 by transmitting beams through the same space. service can be provided. Here, when the time-frequency resources of the beams are the same, interference may occur.

In FIG. 17B , the base station 170 transmits different beams (for example, beams having different beam indexes) through a plurality of panels in the same space, thereby providing a communication service to the terminals 171-1 and 171-2. can provide In FIG. 17C , the base station 170 transmits different beams (eg, beams having different beam indexes) to the same space through one panel, thereby providing communication services to the terminals 171-1 and 171-2. can provide Here, the transmit power of each of the two beams may be 1/2 of the total transmit power of the base station 170 . In order to solve this problem, in FIG. 17D , the base station 170 may provide a communication service to the terminals 171-1 and 171-2 by transmitting one beam in the same space through one panel. Here, two or more beams may be combined. Also, a virtual beam combining method (eg, a panel virtualization method) may be used. When the virtual beam combining method is used, one virtual panel may be set based on a plurality of panels instead of one panel, and one beam may be generated through one virtual panel.

18A is a conceptual diagram illustrating a first embodiment of a method for transmitting a beam through a repeater, and FIG. 18B is a conceptual diagram illustrating a second embodiment of a method for transmitting a beam through a repeater.

In FIG. 18A , interference may occur between beams of the base stations 180 - 1 and 180 - 2 , and in this case, a communication service may be provided to the terminal 182 through the relay 181 . Accordingly, interference between beams may be reduced. When the change of the channel is small or the data transmission amount is increased, communication may be performed based on the beam combining method. For example, in FIG. 18B , the base station 180 may provide a communication service using a combined beam.

19 is a conceptual diagram illustrating a first embodiment of a beam pattern to which a virtual beam combining method is applied, and FIG. 20 is a conceptual diagram illustrating a first embodiment of a beam combined through a virtual beam combining method.

_c,

_c}일 수 있다. ABF/DBF에 기초하여 패널들 각각에 의해 생성된 빔의 지향점은 {

,

}일 수 있다.19 and 20 , one virtual panel may be generated based on a plurality of panels, and the directing point of a beam generated by the virtual panel is {

_c ,

_c }. The directing point of the beam generated by each of the panels based on ABF/DBF is {

,

} can be

In the ABF step, an analog beam may be generated by antenna arrangement and phase shift of each of the panels, and precoding may be performed to generate one combined beam in the panels performing beam combining in the DBF step. A beam combining method in the panels may be classified as follows.

- Beam combining method 1: Beam combining only at ABF stage without panel virtualization

- Beam combining method 2: Beam combining through panel virtualization only in ABF stage

- Beam combining method 3: Beam combining in "ABF + DBF (eg electrical tilting)" step without panel virtualization

- Beam combining method 4: Beam combining through panel virtualization in the "ABF + DBF" stage

- Beam combining method 5: Beam combining through panel virtualization in ABF stage or DBF stage

An array factor according to beam combining may be defined based on Equation 34 below.

)는 아래 수학식 35에 기초하여 정의될 수 있다.In Equation 34, the array factor according to panel virtualization (

) may be defined based on Equation 35 below.

)는 아래 수학식 36에 기초하여 정의될 수 있다.In Equation 34, the array factor (

) may be defined based on Equation 36 below.

은 빔 결합을 위한 수평 패널 인덱스일 수 있고,

은 빔 결합을 위한 수직 패널 인덱스일 수 있고,

는 안테나 엘리먼트들의 개수일 수 있다. 패널들 간의 간격은 아래 수학식 37에 기초하여 정의될 수 있다.In Equation 34,

may be a horizontal panel index for beam combining,

may be a vertical panel index for beam combining,

may be the number of antenna elements. The interval between the panels may be defined based on Equation 37 below.

“Beam combining method 1 (eg, weight and phase shift in beam combining method 1)” may be performed based on Equation 38 below.

는 안테나 엘리먼트들의 개수일 수 있고,

는 수평축에서 안테나 엘리먼트 인덱스일 수 있고,

는 수직축에서 안테나 엘리먼트 인덱스일 수 있고,

은 빔 결합을 위한 수평 패널 인덱스일 수 있고,

은 빔 결합을 위한 수직 패널 인덱스일 수 있다.In Equation 38,

may be the number of antenna elements,

may be an antenna element index in the horizontal axis,

may be the antenna element index in the vertical axis,

may be a horizontal panel index for beam combining,

may be a vertical panel index for beam combining.

는

를 위한 빔 스티어링 각도일 수 있고, 아래 수학식 39에 기초하여 정의될 수 있다.

Is

It may be a beam steering angle for , and may be defined based on Equation 39 below.

는

를 위한 빔 스티어링 각도일 수 있고, 아래 수학식 40에 기초하여 정의될 수 있다.

Is

It may be a beam steering angle for , and may be defined based on Equation 40 below.

“Beam combining method 2 (eg, weight and phase shift in beam combining method 2)” may be performed based on Equation 41 below.

는 안테나 엘리먼트들의 개수일 수 있고,

는 수평축에서 안테나 엘리먼트 인덱스일 수 있고,

는 수직축에서 안테나 엘리먼트 인덱스일 수 있고,

은 빔 결합을 위한 수평 패널 인덱스일 수 있고,

은 빔 결합을 위한 수직 패널 인덱스일 수 있다.In Equation 41,

may be the number of antenna elements,

may be an antenna element index in the horizontal axis,

may be the antenna element index in the vertical axis,

may be a horizontal panel index for beam combining,

may be a vertical panel index for beam combining.

In Equation 41, m _c may be defined based on Equation 42 below, and n _c may be defined based on Equation 43 below.

는

를 위한 빔 스티어링 각도일 수 있고, 앞서 설명된 수학식 39에 기초하여 정의될 수 있다.

는

를 위한 빔 스티어링 각도일 수 있고, 앞서 설명된 수학식 40에 기초하여 정의될 수 있다.

Is

It may be a beam steering angle for , and may be defined based on Equation 39 described above.

Is

It may be a beam steering angle for , and may be defined based on Equation 40 described above.

“Beam combining method 3 (eg, weight and phase shift in beam combining method 3)” may be performed based on Equation 44 below.

는 안테나 엘리먼트들의 개수일 수 있고,

는 수평축에서 안테나 엘리먼트 인덱스일 수 있고,

는 수직축에서 안테나 엘리먼트 인덱스일 수 있고,

은 빔 결합을 위한 수평 패널 인덱스일 수 있고,

은 빔 결합을 위한 수직 패널 인덱스일 수 있다.

는

를 위한 빔 스티어링 각도일 수 있고, 아래 수학식 45에 기초하여 정의될 수 있다.In Equation 44,

may be the number of antenna elements,

may be an antenna element index in the horizontal axis,

may be the antenna element index in the vertical axis,

may be a horizontal panel index for beam combining,

may be a vertical panel index for beam combining.

Is

It may be a beam steering angle for , and may be defined based on Equation 45 below.

는

를 위한 빔 스티어링 각도일 수 있고, 아래 수학식 46에 기초하여 정의될 수 있다.

Is

It may be a beam steering angle for , and may be defined based on Equation 46 below.

“Beam combining scheme 4 (eg, weight and phase shift in beam combining scheme 4)” may be performed based on Equation 47 below.

는 안테나 엘리먼트들의 개수일 수 있고,

는 수평축에서 안테나 엘리먼트 인덱스일 수 있고,

는 수직축에서 안테나 엘리먼트 인덱스일 수 있고,

은 빔 결합을 위한 수평 패널 인덱스일 수 있고,

은 빔 결합을 위한 수직 패널 인덱스일 수 있다.In Equation 47,

may be the number of antenna elements,

may be an antenna element index in the horizontal axis,

may be the antenna element index in the vertical axis,

may be a horizontal panel index for beam combining,

may be a vertical panel index for beam combining.

는

를 위한 빔 스티어링 각도일 수 있고, 앞서 설명된 수학식 45에 기초하여 정의될 수 있다.

는

를 위한 빔 스티어링 각도일 수 있고, 앞서 설명된 수학식 46에 기초하여 정의될 수 있다.m _c may be defined based on Equation 42 described above, and n _c may be defined based on Equation 43 described above.

Is

It may be a beam steering angle for , and may be defined based on Equation 45 described above.

Is

It may be a beam steering angle for , and may be defined based on Equation 46 described above.

Meanwhile, when panel virtualization is performed in the ABF step, "beam combining method 2" and "beam combining method 3" may be applied. When panel virtualization is performed in the DBF step, "beam combining method 1", "beam combining method 3", and "beam combining method 4" may be applied. When panel virtualization (eg, beam combining) is performed, the antenna gain may be as follows.

21 is a graph illustrating a first embodiment of an antenna gain and a beam pattern in an embodiment to which panel virtualization is applied.

Referring to FIG. 21 , a beam pattern and antenna gain generated by 8×8 antenna elements in one panel can be confirmed, and a beam pattern generated by 32×32 antenna elements formed through virtualization of 4×4 panels Beam pattern and antenna gain can be ascertained. When panel virtualization is applied, a relatively narrow beam may be generated, and a relatively high antenna gain may be generated. Here, a coverage hole (eg, a coverage hole in which an antenna gain of -3 dB compared to a directing point occurs) may be compensated by DBF.

22 is a graph illustrating a first embodiment of an antenna gain and a beam pattern according to a beam combining method.

Referring to FIG. 22 , “Alt1” may indicate “beam combining method 1” and “Alt2” may indicate “beam combining method 2”. In the embodiment to which "Alt2" is applied, the beam width may be narrower than the beam width in the embodiment to which "Alt1" is applied. Antenna gain may increase as the number of virtualized panels increases (eg, 1+1, 2+2, 4+4, 8+8).

■ Combined beam codebook according to panel- based beamforming

는 적어도 하나의 패널에서 {

,

}로 매핑되는 빔포밍 벡터일 수 있고,

는 아날로그 빔을 지시할 수 있고,

는 디지털 빔을 지시할 수 있다.

,

및

는 송신기와 수신기에서 공유될 수 있다. 빔 결합에 따른 빔 스티어링 각도(

,

)를 위한 코드북(

)은 아래 수학식 48에 기초하여 정의될 수 있다.

in at least one panel {

,

} may be a beamforming vector mapped to,

may indicate an analog beam,

may indicate a digital beam.

,

and

may be shared by the transmitter and the receiver. Beam steering angle according to beam combination (

,

) for the codebook (

) may be defined based on Equation 48 below.

는 수학식 49에 기초하여 빔 패턴(예를 들어, 빔폭, 지향점)의 서비스 영역의 각도에 따라 양자화될 수 있다.

may be quantized according to the angle of the service area of the beam pattern (eg, beam width, directing point) based on Equation 49.

■ Beam measurement procedure

In order to perform a beam-related operation (eg, a beam selection operation, a beam change operation, a HARQ retransmission operation, a link adaptation operation, etc.), the receiver is configured to perform a channel state (eg, , beam state) can be measured. For example, the receiver may select an effective channel (h _eff ) based on the strength of a received signal (eg, a reference signal, a synchronization signal) according to a beam pattern, and , information on a beam corresponding to the selected effective channel (h _eff ) may be reported to the transmitter. The effective channel h _eff may be determined based on Equation 50 below.

는 수평축에서 다중 전송 아날로그 빔들(multiple transmit analog beams)을 선택하기 위한 후보 집합을 지시할 수 있고,

는 수직축에서 다중 전송 아날로그 빔들을 선택하기 위한 후보 집합을 지시할 수 있다.

및

각각은 아래 수학식 51에 기초하여 정의될 수 있다.In Equation 50,

may indicate a candidate set for selecting multiple transmit analog beams in the horizontal axis,

may indicate a candidate set for selecting multiple transmission analog beams on the vertical axis.

and

Each may be defined based on Equation 51 below.

■ Beam finding procedure

"번 수행될 수 있다. 수신기에서 수신 빔포밍이 적용되는 경우, 빔 검색 절차의 수행 횟수는 수신기의 빔들의 개수에 따라 증가할 수 있다. 예를 들어, 빔 검색 절차의 수행 횟수는

일 수 있다. 여기서, M_r은 수신기의 빔들의 개수일 수 있다. 빔 검색 절차는 아래 방식들에 기초하여 수행될 수 있다.The beam search procedure includes the steps of searching for an optimal beam among beams (eg, fixed beam, analog beam) generated in the analog stage and the beam generated in the digital stage (eg, digital beam, electrically tilted beam) It may include searching for an optimal beam among them. In order to search for an optimal beam through the measurement procedure of beams received in different spaces, the beam search procedure is

"Could be performed once. When reception beamforming is applied in the receiver, the number of times of performing the beam search procedure may increase according to the number of beams of the receiver. For example, the number of times of performing the beam search procedure is

can be Here, M _r may be the number of beams of the receiver. The beam search procedure may be performed based on the following methods.

Beam search method 1

When a beam pattern for an analog beam (hereinafter referred to as "analog beam pattern") and a beam pattern for a digital beam (hereinafter referred to as "digital beam pattern") are respectively defined, the receiver completes the search for the analog beam. Afterwards, the digital beam can be retrieved.

는 아날로그 빔 패턴에서 수평 아날로그 빔의 지향 각도를 지시할 수 있고,

는 빔 패턴에서 수직 아날로그 빔의 지향 각도를 지시할 수 있다.- Step 1: The receiver may receive a signal (eg reference signal, synchronization signal, etc.) from the transmitter, and based on the quality of the received signal, at least one of the analog beams (eg analog beam pattern) An analog beam (eg, an analog beam having a received signal strength greater than or equal to a preset threshold) may be searched for (or selected). Step 1 may be performed based on Equation 52 below. In Equation 52,

may indicate the orientation angle of the horizontal analog beam in the analog beam pattern,

may indicate the directing angle of the vertical analog beam in the beam pattern.

각각은 단계 1에서 선택된

을 지시할 수 있다.- Step 2: The receiver selects an optimal digital beam (for example, a digital beam having a received signal strength greater than or equal to a preset threshold) among the beam pairs (for example, a digital beam corresponding to the searched analog beam) searched in step 1 You can search (or select). The optimal digital beam may be determined based on the quality of the signal received from the transmitter. Here, the digital beam corresponding to the analog beam may be an electrically tilted beam based on the analog beam. In addition, the receiver may search for a digital precoding vector for an optimal digital beam. Step 2 may be performed based on Equation 53 below, and in Equation 53

each selected in step 1

can be instructed.

Beam search method 2

_i는 아날로그 빔 패턴에서 임의의 수평 아날로그 빔(예를 들어, 임의의 수평 아날로그 빔의 지향각)일 수 있다.Step 1: The receiver may receive a signal (eg, a reference signal, a synchronization signal, etc.) from the transmitter, and based on the quality of the received signal, at least one of the horizontal analog beams (eg, An analog beam having a received signal strength greater than or equal to a preset threshold) may be searched for (or selected). Step 1 may be performed based on Equation 54 below, and in Equation 54

_i may be any horizontal analog beam (eg, the beam angle of any horizontal analog beam) in the analog beam pattern.

각각은 수학식 54의

에 기초하여 선택된

일 수 있다.- Step 2: The receiver searches for (or selects) at least one vertical analog beam (eg, an analog beam having a received signal strength greater than or equal to a preset threshold) among vertical analog beams based on the quality of the received signal. can Step 2 may be performed based on Equation 55 below, and in Equation 55

Each of Equation 54

selected based on

can be

- Step 3: The receiver receives an optimal digital beam (for example, a received signal above a preset threshold value) among the beam pairs (for example, a digital beam corresponding to the searched horizontal analog beam and vertical analog beam) searched for in steps 1 and 2 A digital beam having an intensity) may be searched for (or selected). The optimal digital beam may be determined based on the quality of the signal received from the transmitter. Here, the digital beam corresponding to the horizontal analog beam and the vertical analog beam may be an electrically tilted beam based on the corresponding analog beam. In addition, the receiver may search for a digital precoding vector for an optimal digital beam. Step 3 may be performed based on Equation 56 below.

Beam search method 3

Step 1: The receiver may receive a signal (eg, a reference signal, a synchronization signal, etc.) from the transmitter, and based on the quality of the received signal, at least one of the horizontal analog beams (eg, An analog beam having a received signal strength greater than or equal to a preset threshold) may be searched for (or selected). Step 1 may be performed based on Equation 54 described above.

- Step 2: The receiver searches for (or selects) at least one vertical analog beam (eg, an analog beam having a received signal strength greater than or equal to a preset threshold) among vertical analog beams based on the quality of the received signal. can Step 2 may be performed based on Equation 55 described above.

각각은

에 기초하여 선택된

일 수 있고,

_e,i는 디지털 빔 패턴에서 임의의 수평 디지털 빔(예를 들어, 임의의 수평 디지털 빔의 지향각)일 수 있다.- Step 3: The receiver receives an optimal horizontal digital beam (for example, a digital beam having a received signal strength greater than or equal to a preset threshold value) among the beam pairs searched in step 1 (for example, a horizontal digital beam corresponding to the searched horizontal analog beam) beam) can be searched (or selected). The optimal horizontal digital beam may be determined based on the quality of the signal received from the transmitter. Here, the horizontal digital beam corresponding to the horizontal analog beam may be an electrically tilted beam based on the corresponding analog beam. Step 3 may be performed based on Equation 57 below. In Equation 57,

each

selected based on

can be,

_e,i may be any horizontal digital beam (eg, the beam angle of any horizontal digital beam) in the digital beam pattern.

는

에 기초하여 선택된

_e일 수 있다.- Step 4: The receiver receives an optimal vertical digital beam (for example, a digital beam having a received signal strength greater than or equal to a preset threshold value) among the beam pairs searched in step 2 (for example, a vertical digital beam corresponding to the searched vertical analog beam) beam) can be searched (or selected). The optimal vertical digital beam may be determined based on the quality of the signal received from the transmitter. Here, the vertical digital beam corresponding to the vertical analog beam may be an electrically tilted beam based on the corresponding analog beam. Step 4 can be performed based on Equation 58 below,

Is

selected based on

can be _e .

Meanwhile, according to the beam search method 1-3 described above, a search delay may occur. The search delay can be:

23 is a graph illustrating a search delay according to a beam search method.

"일 수 있고, Alt1의 빔 검색 복잡도는 "

"일 수 있고, Alt2의 빔 검색 복잡도는 "

"일 수 있고, Alt3의 빔 검색 복잡도는 "

"일 수 있다.Referring to FIG. 23 , “Alt1” may indicate “beam search method 1”, “Alt2” may indicate “beam search method 2”, and “Alt3” may indicate “beam search method 3”. can direct A full search (FS) may indicate a method of searching all beams. “A” may indicate an “analog beam” and “D” may indicate a “digital beam”. The number of beam search attempts of the FS may be greater than the number of beam search attempts of Alt1, Alt2, and Alt3 respectively, and the number of beam search attempts of Alt3 may be the smallest. For example, the beam search complexity of FS (e.g., the number of beam search attempts) is "

"can be, the beam search complexity of Alt1 is "

"can be, the beam search complexity of Alt2 is "

"can be, Alt3's beam search complexity is "

"It could be

■ Beam measurement procedure

In the beam measurement procedure, a beam state (eg, a channel state) may be measured, and the beam state may be measured within a measurement resource unit (MRU). The MRU may be a subcarrier to which a signal (hereinafter, referred to as a “beam measurement signal”) used for measuring a beam state among subcarriers is allocated. The beam measurement signal may be a reference signal (RS), a synchronization signal (SS), a beam measurement-reference signal (BM-RS), a beam sweeping (BWS) signal, or the like. The beam measurement procedure may be classified as shown in Table 6 below.

In the beam measurement procedure, the measurement result may be converted in dB unit or dBm unit, and the receiver may report the converted value to the transmitter. Alternatively, the receiver may quantize the measurement result and report the quantized value to the transmitter. Alternatively, the receiver may report a signal to interference plus noise ratio (SINR), a received signal strength indicator (RSSI), or a received signal strength (RSS) to the transmitter as a measurement result. In this case, the transmitter may estimate the SINR based on RSSI or RSS.

24 is a conceptual diagram illustrating a first embodiment of a beam measurement procedure.

개의 빔 측정 신호들이 전송될 수 있다. 수신기는 송신기로부터 수신된 빔 측정 신호에 기초하여 빔 측정을 수행할 수 있고, 측정 결과를 송신기에 보고할 수 있다. t_m 구간에서 측정 결과(

)는 아래 수학식 59에 기초하여 계산될 수 있다. 예를 들어, t_m 구간에서 측정 결과는 이전 구간(t_m-1)에서 측정 값과 현재 구간(t_m)에서 측정 값에 기초하여 계산될 수 있다.Referring to FIG. 24 , a transmitter may transmit a beam measurement signal (eg, a reference signal, a synchronization signal, a BM-RS, and a BSW signal). The beam measurement signal may be transmitted based on a preset period. Here, each of m and n may be an integer of 1 or more. In the section corresponding to one n (hereinafter referred to as "OS")

n beam measurement signals may be transmitted. The receiver may perform beam measurement based on the beam measurement signal received from the transmitter, and may report the measurement result to the transmitter. Measurement results in the interval t _m (

) can be calculated based on Equation 59 below. For example, the measurement result in the t _m section may be calculated based on the measured value in the previous section (t _m −1) and the measured value in the current section (t _m ).

는 러닝 에버리징 파라미터(running averaging parameter)일 수 있다.

는 "t_m = m" 구간 내의 n 구간 동안의 빔 측정 신호의 측정 값일 수 있고, 아래 수학식 60에 기초하여 정의될 수 있다.

may be a running averaging parameter.

may be a measurement value of the beam measurement signal for n periods within the "t _m = m" period, and may be defined based on Equation 60 below.

는 이전 구간(t_n = n-1)까지의 측정 값(

)과 현재 구간(t_n = n)에서 측정 값에 기초하여 계산될 수 있다. 예를 들어,

는 아래 수학식 61에 기초하여 계산될 수 있다. 여기서,

는 러닝 에버리징 파라미터일 수 있다.

is the measured value up to the previous interval (t _n = n-1) (

) and the current interval (t _n = n) may be calculated based on the measured values. for example,

can be calculated based on Equation 61 below. here,

may be a running averaging parameter.

은 "t_n = n" 구간 내의 적어도 하나의 빔 측정 신호에 기초하여 측정될 수 있으며, 아래 수학식 62에 기초하여 정의될 수 있다.

may be measured based on at least one beam measurement signal within the "t _n = n" interval, and may be defined based on Equation 62 below.

는 이전 구간(t_os = OS - 1)까지의

와 현재 구간(t_os = OS)에서 측정 값에 기초하여 계산될 수 있다. 예를 들어,

는 아래 수학식 63에 기초하여 계산될 수 있다. 여기서,

는 러닝 에버리징 파라미터일 수 있다.

is up to the previous interval (t _os = OS - 1)

and can be calculated based on the measured values in the current section (t _os = OS). for example,

can be calculated based on Equation 63 below. here,

may be a running averaging parameter.

는 "t_os = OS" 구간에서 빔 측정 신호의 측정 값일 수 있으며, 아래 수학식 64에 기초하여 계산될 수 있다.

may be a measurement value of the beam measurement signal in the "t _os = OS" section, and may be calculated based on Equation 64 below.

는 송신기의 RF 체인을 위한 아날로그 빔별 빔 측정 신호 #j(즉, BM-RS #j)를 위해 할당된 OFMD 심볼들에서 서브캐리어들의 개수를 지시할 수 있고,

각각은 BM-RS #j의 측정을 위해 송신기와 수신기 간에 미리 설정된

일 수 있다.

는 수평축에서 다중 전송 아날로그 빔들을 선택하기 위한 후보 집합을 지시할 수 있고,

는 수직축에서 다중 전송 아날로그 빔들을 선택하기 위한 후보 집합을 지시할 수 있다.

및

각각은 아래 수학식 65에 기초하여 정의될 수 있다.

may indicate the number of subcarriers in the OFMD symbols allocated for the beam measurement signal #j (ie, BM-RS #j) for each analog beam for the RF chain of the transmitter,

Each is preset between transmitter and receiver for measurement of BM-RS #j

can be

may indicate a candidate set for selecting multiple transmission analog beams in the horizontal axis,

may indicate a candidate set for selecting multiple transmission analog beams on the vertical axis.

and

Each may be defined based on Equation 65 below.

는 아래 수학식 66 내지 수학식 69에 기초하여 계산될 수 있다.or,

may be calculated based on Equations 66 to 69 below.

로 설정될 수 있다.

는 송신기의 RF 체인을 위한 아날로그 빔별 참조 신호(RS) #j를 위해 할당된 OFDM 심볼들에서 서브캐리어들의 개수를 지시할 수 있다.N _sc may indicate the number of subcarriers in OFDM symbols for measurement of physical channel state information in the transmitter. For example, N _sc may indicate the total number of subcarriers in one MRU or a plurality of MRUs (eg, maximum system bandwidth). Alternatively, when the channel is measured based on the reference signal RS, N _sc is

can be set to

may indicate the number of subcarriers in OFDM symbols allocated for reference signal (RS) #j for each analog beam for the RF chain of the transmitter.

s[k] may indicate the transmission power of a signal (eg, a reference signal (RS), sample, message) transmitted in the k-th subcarrier. s[k] may be defined or indicated prior to transmission of a signal. r[k] may indicate the reception power of a signal (eg, a reference signal RS, a sample, a message) received in the k-th subcarrier. Here, r[k] may indicate reception power of a signal excluding interference and noise, and may be defined based on Equation 70 below.

각각은 참조 신호(RS) #j의 측정을 위해 송신기와 수신기 간에 미리 설정된

일 수 있고,

는 수평축에서 다중 전송 아날로그 빔들을 선택하기 위한 후보 집합을 지시할 수 있고,

는 수직축에서 다중 전송 아날로그 빔들을 선택하기 위한 후보 집합을 지시할 수 있다.

및

각각은 앞서 설명된 수학식 65에 기초하여 정의될 수 있다. RSSI[k]는 k번째 서브캐리어에서 수신되는 신호(예를 들어, RS, 샘플, 메시지)의 수신 전력을 지시할 수 있다. 여기서, RSSI[k]는 간섭 및 잡음을 포함하는 신호의 수신 전력을 지시할 수 있다.

Each is preset between transmitter and receiver for measurement of reference signal (RS) #j

can be,

may indicate a candidate set for selecting multiple transmission analog beams in the horizontal axis,

may indicate a candidate set for selecting multiple transmission analog beams on the vertical axis.

and

Each may be defined based on Equation 65 described above. RSSI[k] may indicate the reception power of a signal (eg, RS, sample, message) received in the k-th subcarrier. Here, RSSI[k] may indicate the reception power of a signal including interference and noise.

The receiver may include at least one antenna used for beam measurement. In this case, Equation 71 below may be used.

는 빔 측정을 수행하는 수신기의 안테나 #r의

일 수 있고,

는 수신기에서 빔 측정을 수행하는 안테나들(예를 들어, 안테나 엘리먼트들)의 개수를 지시할 수 있다. 수신기는 빔 측정을 수행하는 모든 안테나들에서 측정된 평균값을 계산할 수 있고, 평균값을 송신기에 보고할 수 있다. 여기서, 평균값은 아래 수학식 72에 기초하여 계산될 수 있다.

is the antenna #r of the receiver performing the beam measurement

can be,

may indicate the number of antennas (eg, antenna elements) for performing beam measurement in the receiver. The receiver may calculate an average value measured by all antennas performing beam measurement, and may report the average value to the transmitter. Here, the average value may be calculated based on Equation 72 below.

,

및

을 측정할 수 있고, 측정된 값을 송신기에 보고할 수 있다.Meanwhile, when a communication service is provided through a plurality of beams in a sector, interference between the beams may occur. When one transmitter provides a communication service in a plurality of sectors that are distinguished in a spatial domain, interference between the sectors may occur. When adjacent transmitters transmit signals, interference may occur between adjacent transmitters. The interference described above may be measured through beam measurement-interference measurement (BM-IM), and resources (eg, resource element (RE), subcarrier, symbol) for BM-IM may be configured. The receiver may measure beam interference in the resource for BM-IM, and the transmitter may not transmit any signal through the resource configured for the BM-IM. Receiver from the resource set for BM-IM

,

and

can be measured, and the measured value can be reported to the transmitter.

25 is a conceptual diagram illustrating a second embodiment of a beam measurement procedure.

Referring to FIG. 25 , the base station 2500 transmits a beam measurement signal (eg, a reference signal, BM-) through four beams (eg, beam #0, beam #1, beam #2, beam #3). RS, sync signal, BSW signal) can be transmitted. Here, the indices of the four beams may be different from each other, and the beam measurement signal may be transmitted in a beamforming method. The beam measurement signal may be transmitted based on the following schemes.

26A is a timing diagram illustrating a first embodiment of a transmission method of a beam measurement signal.

Referring to FIG. 26A , the base station 2500 may transmit a BSW signal and a BM-RS used for beam measurement. Each of the BSW signal and the BM-RS may be transmitted periodically, and the BM-RS may be transmitted in a beamforming manner.

26B is a timing diagram illustrating a second embodiment of a method of transmitting a beam measurement signal.

Referring to FIG. 26B , the base station 2500 may transmit a BSW signal used for beam measurement, a BM-RS, and a combined BM-RS. The combined BM-RS may be a BM-RS transmitted through the combined beam. Each of the BSW signal, the BM-RS and the combined BM-RS may be transmitted periodically, and the BM-RS and the combined BM-RS may be transmitted in a beamforming manner.

Referring back to FIG. 25 , the terminal 2510 may perform beam measurement based on a beam measurement signal received from the base station. For example, the terminal 2510 may select at least one beam whose beam measurement result satisfies a preset criterion (eg, at least one beam having a received signal strength equal to or greater than a preset threshold value). When the beams satisfying the preset criteria are beam #1 and beam #2, the terminal 2510 may transmit information (eg, beam index) indicating the beam #1 and beam #2 to the base station 2500 . have.

The base station 2500 may receive beam information (eg, beam #1 and beam #2) selected based on the beam measurement signal from the terminal 2510, and using the beam #1 and beam #2, the terminal ( 2510) may provide a communication service. In this case, the base station 2500 may provide a communication service to the terminal 2510 using beams #1 and #2 having different indices. Alternatively, the base station 2500 may provide a communication service to the terminal 2510 using a combined beam (eg, beam #1 and beam #2). For example, when a measurement result based on the combined BM-RS (eg, the BM-RS transmitted through the combined beam #1 and beam #2) is received from the terminal 2510, the base station 2500 is It can be seen that the corresponding measurement result is a measurement result based on the combined BM-RS, and a communication service can be provided to the terminal 2510 using the combined beam #1 and beam #2 indicated by the measurement result.

Meanwhile, the beam measurement signal may be transmitted through some or all of the time-frequency resources. When the beam measurement signal is transmitted through a time-frequency resource shared with other signals (eg, control information, user data, other reference signals, other beam measurement signals) or a separate time-frequency resource, the receiver receives the received It should be able to recognize that the signal is a beam measurement signal.

Accordingly, a resource pool for the beam measurement signal may be configured, and resources belonging to the resource pool may be mapped to each of the beam measurement signals. For example, each of the beam measurement signals may be mapped to a different resource in a resource pool, the base station may transmit a plurality of beam measurement signals using different resources in the resource pool, and the terminal may transmit a resource of the beam measurement signal. It is possible to identify its own beam measurement signal based on the mapping information.

The resource pool may be set in a time unit (eg, a subframe, a transmission time interval (TTI), a slot, etc.), and may be periodically set in a time axis. A periodic beam measurement procedure may be performed based on the resource pool. When the beam measurement procedure is triggered by the transmitter, the message triggering the beam measurement procedure may include resource pool information. In addition, the resource pool may be configured in frequency units (eg, physical radio unit (PRU) or physical resource unit (PRU), subband, subchannel). For example, all frequency resources or some frequency resources may be allocated for the resource pool. In addition, the resource pool may be set in units of time-frequency and may be set in units of space (eg, beam index). A plurality of resource pools may be configured, and each of the plurality of resource pools may not be used for transmission of other signals (eg, control information, user data, other reference signals, and other beam measurement signals).

In the resource pool, the beam measurement signal may be configured to be distinguishable on the time axis and/or the frequency axis. For example, the beam measurement signal may be set in units of OFDM symbols (eg, consecutive OFDM symbols) on the time axis, and set in units of subcarriers (eg, consecutive subcarriers) on the frequency axis can be A specific resource (eg, resource element (RE), tone, symbol, etc.) in one resource pool may be mapped to a beam measurement signal. When there are many beam measurement signals, a plurality of resource pools may be configured. In addition, when there are a plurality of receivers, a resource pool for each of the plurality of receivers may be independently configured.

Meanwhile, the beam measurement signal may be configured in a resource pool (eg, MRU), and the beam measurement signal in the MRU may be configured as follows.

27 is a conceptual diagram illustrating configuration of a beam measurement signal in an MRU.

Referring to FIG. 27 , at least one measurement period may be set within a measurement window, and at least one measurement duration may be set within the measurement period, and at least within the measurement period One MRU may be configured. The beam measurement procedure may be performed within a measurement duration, and the measurement duration may be started after a preset offset from the start time of the measurement period. The measurement report may be performed after a response delay from an end time of the measurement duration.

The MRU may be a minimum resource unit configured for a beam measurement procedure. An MRU may consist of one OFDM symbol or consecutive OFDM symbols (eg, frame, subframe, TTI, slot) in the time axis, and one subcarrier or consecutive subcarriers (eg, in the frequency axis) For example, it may be composed of a resource block (RB), a subband, a subchannel, an entire frequency band). At least one beam measurement signal may be configured in the MRU, and the beam measurement signals may be configured to be distinguished in at least one of a time domain, a frequency domain, and a spatial domain.

The methods according to the present invention may be implemented in the form of program instructions that can be executed by various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions recorded on the computer readable medium may be specially designed and configured for the present invention, or may be known and available to those skilled in the art of computer software.

Examples of computer-readable media include hardware devices specially configured to store and carry out program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include not only machine language codes such as those generated by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like. The hardware device described above may be configured to operate as at least one software module to perform the operations of the present invention, and vice versa.

Although it has been described with reference to the above embodiments, it will be understood by those skilled in the art that various modifications and changes can be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. will be able

Claims (20)

A communication method based on hybrid beamforming in a receiver of a communication system, comprising:
receiving reference signals from a transmitter of the communication system through analog beams and digital beams to which the hybrid beamforming is applied;
selecting at least one analog beam having a quality equal to or greater than a preset threshold value from among the analog beams based on a measurement result of the reference signals received through the analog beams;
identifying at least one digital beam that is tilted with respect to the at least one analog beam among the digital beams;
selecting one or more digital beams having a quality equal to or greater than the preset threshold value from among the one or more digital beams based on measurement results of the reference signals received through the at least one digital beam; and
and transmitting information indicating at least one of the at least one analog beam and the one or more digital beams to the transmitter. The method according to claim 1,
The step of selecting the at least one analog beam comprises:
selecting at least one horizontal analog beam having a quality equal to or greater than the preset threshold value from among horizontal analog beams belonging to the analog beams; and
The method further comprising the step of selecting at least one vertical analog beam having a quality equal to or greater than the preset threshold value from among vertical analog beams belonging to the analog beams. 3. The method according to claim 2,
The at least one vertical analog beam is an analog beam disposed in a vertical direction to the at least one horizontal analog beam. 3. The method according to claim 2,
Identifying the at least one digital beam comprises:
identifying at least one horizontal digital beam tilted with respect to the at least one horizontal analog beam among horizontal digital beams belonging to the digital beams; and
identifying at least one vertical digital beam tilted with respect to the at least one vertical analog beam among vertical digital beams belonging to the digital beams;
The step of selecting one or more digital beams comprises:
selecting one or more horizontal digital beams having a quality equal to or greater than the preset threshold value from among the one or more horizontal digital beams; And
The method further comprising the step of selecting one or more vertical digital beams having a quality equal to or greater than the preset threshold value from among the at least one vertical digital beam. 5. The method according to claim 4,
wherein the one or more vertical digital beams are digital beams disposed in a vertical direction with the one or more horizontal digital beams. The method according to claim 1,
and the reference signals are received via a combined beam of the transmitter. delete The method according to claim 1,
The step of selecting one or more digital beams comprises:
The method of claim 1, further comprising: ascertaining a precoding vector of the one or more digital beams. A communication method based on hybrid beamforming in a transmitter of a communication system, comprising:
transmitting reference signals using analog beams and digital beams tilted with respect to the analog beams;
receiving, from a receiver of the communication system, information indicating at least one of at least one analog beam and one or more digital beams selected based on the reference signals; and
performing communication with the receiver using at least one of the at least one analog beam and the one or more digital beams;
An antenna module of the transmitter includes a plurality of beamformers supporting different sectors, each of the plurality of beamformers includes a plurality of panels, and a plurality of panels each of which includes a plurality of antenna elements, the analog beams and the digital beams are transmitted by one beamformer, and the one or more digital beams are tilted with respect to the at least one analog beam. A communication method, wherein the digital beam is selected based on measurement results of the reference signals. 10. The method of claim 9,
The reference signals are transmitted through time-frequency resources excluding time-frequency resources configured for interference measurement. delete 10. The method of claim 9,
The reference signals are transmitted through a combined beam of at least two of the analog beams and the digital beams. 13. The method of claim 12,
The combined beam is generated by virtualizing panels belonging to one beamformer to have one directing point. A receiver in a communication system, comprising:
processor; and
At least one instruction executed by the processor comprises a memory (memory) stored,
The at least one command is
receiving reference signals from a transmitter of the communication system through analog beams and digital beams to which hybrid beamforming is applied;
selecting at least one analog beam having a quality equal to or greater than a preset threshold value from among the analog beams based on a measurement result of the reference signals received through the analog beams;
identify at least one digital beam that is tilted with respect to the at least one analog beam among the digital beams;
selecting one or more digital beams having a quality equal to or higher than the preset threshold value from among the one or more digital beams based on a measurement result of the reference signals received through the at least one digital beam; and
and transmit information indicating at least one of the at least one analog beam and the one or more digital beams to the transmitter. 15. The method of claim 14,
When selecting the at least one analog beam, the at least one command includes:
selecting at least one horizontal analog beam having a quality equal to or greater than the preset threshold value from among horizontal analog beams belonging to the analog beams; and
and selecting at least one vertical analog beam having a quality equal to or greater than the preset threshold value from among vertical analog beams belonging to the analog beams. 16. The method of claim 15,
When identifying the at least one digital beam, the at least one command includes:
identifying at least one horizontal digital beam tilted with respect to the at least one horizontal analog beam among horizontal digital beams belonging to the digital beams; and
and identifying at least one vertical digital beam tilted with respect to the at least one vertical analog beam among vertical digital beams belonging to the digital beams;
When selecting the one or more digital beams, the at least one command includes:
selecting one or more horizontal digital beams having a quality equal to or greater than the preset threshold value from among the one or more horizontal digital beams; and
and select one or more vertical digital beams having a quality equal to or greater than the preset threshold value from among the at least one vertical digital beam. 17. The method of claim 16,
wherein the at least one vertical analog beam is an analog beam disposed in a vertical direction with the at least one horizontal analog beam, and the at least one vertical digital beam is a digital beam disposed in a vertical direction with the at least one horizontal digital beam. 15. The method of claim 14,
and the reference signals are received via a combined beam of the transmitter. delete 15. The method of claim 14,
When selecting the one or more digital beams, the at least one command includes:
and identify a precoding vector of the one or more digital beams.

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