KR20240081799A - Method and apparatus for setting beamforming direction - Google Patents

Abstract

A method and apparatus for searching the beam direction of a terminal in a communication system are disclosed. The beam direction search method of the terminal includes the steps of checking the link status with the base station based on the received signal strength of a signal received by beamforming from the base station; When the link state is line of sight (LoS), setting the priority of beam direction search in the order of azimuth (AZ) direction search and elevation (EL) direction search; When the link state is none-line of sight (NLoS), setting the priority of beam direction search in the order of elevation (EL) direction search and azimuth (AZ) direction search; And it may include sequentially searching for beam directions based on the set priority.

Description

Beamforming direction setting method and device {METHOD AND APPARATUS FOR SETTING BEAMFORMING DIRECTION}

The present invention relates to beamforming technology, and more specifically, to a method and device for setting a beam direction in a communication system using beamforming.

Since path loss is large in high frequency bands, a beamforming method using a high-gain directional antenna or multiple array antenna is used to increase received power. These directional antennas or beamforming methods have high gain but small beam width, so if the beam direction is not properly aligned, power loss is significant and it may be difficult to maintain a communication channel.

In order to maintain the communication channel, the beam direction must be continuously tracked so that beam direction search can be performed to determine the direction of the beam in the early stages when the communication channel is not disconnected or the communication link is not established even in situations such as blocking. do.

The purpose of the present invention to solve the above problems is to provide a method and device for beam direction discovery and tracking using link state information in a communication system.

In order to achieve the above object, the beam direction search method of the terminal according to the first embodiment of the present invention determines the link status with the base station based on the received signal strength of the signal received by beamforming from the base station. Confirmation steps; When the link state is line of sight (LoS), setting the priority of beam direction search in the order of azimuth (AZ) direction search and elevation (EL) direction search; When the link state is none-line of sight (NLoS), setting the priority of beam direction search in the order of elevation (EL) direction search and azimuth (AZ) direction search; And it may include sequentially searching for beam directions based on the set priority.

Using embodiments of the present invention, the beam direction search time can be shortened, so the beam direction setting time can be shortened even in the event of sudden blocking, and the communication channel can be continuously maintained. Additionally, the link setup time can be shortened during initial link setup. According to the above-described operation, beam direction search and tracking can be performed efficiently, and the performance of the communication system can be improved.

1 is a conceptual diagram illustrating an embodiment of a communication system.
Figure 2 is a block diagram showing an embodiment of a communication node constituting a communication system.
Figure 3 is a graph to explain additional loss according to antenna beam width.
Figure 4 is a conceptual diagram for explaining sequential beamforming in a base station.
Figure 5 is a block diagram showing an embodiment of a beam direction search device through link state recognition.
Figure 6 is a flowchart showing an embodiment of a beam direction search device through link state recognition.
Figure 7 is a flowchart of a beam direction setting procedure through link status checking according to an embodiment of the present invention.
Figure 8 is a flowchart of hierarchical beam search in beam direction search according to an embodiment of the present invention.

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

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

In embodiments of the present application, “at least one of A and B” may mean “at least one of A or B” or “at least one of combinations of one or more of A and B.” Additionally, in embodiments of the present application, “one or more of A and B” may mean “one or more of A or B” or “one or more of combinations of one or more of A and B.”

When a component is said to be "connected" or "connected" to another component, it is understood that it may be directly connected to or connected to the other component, but that other components may exist in between. It should be. On the other hand, when it is mentioned that a component is “directly connected” or “directly connected” to another component, it should be understood that there are no other components in between.

The terms used in this application are only used to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, terms such as “comprise” or “have” are intended to designate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features. It should be understood that this does not exclude in advance the possibility of the existence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by a person of ordinary skill in the technical field to which the present invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and should not be interpreted in an ideal or excessively formal sense unless explicitly defined in the present application. No.

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

A communication system to which embodiments according to the present invention are applied will be described. The communication systems to which the embodiments according to the present invention are applied are not limited to those described below, and the embodiments according to the present invention can be applied to various communication systems. Here, communication system may be used in the same sense as communication network.

In an embodiment, “setting an operation (e.g., a transmission operation)” means “setting information (e.g., information element, parameter) for the operation” and/or “performing the operation.” This may mean that “indicating information” is signaled. “An information element (eg, parameter) is set” may mean that the information element is signaled. Signaling includes system information (SI) signaling (e.g., transmission of system information block (SIB) and/or master information block (MIB)), RRC signaling (e.g., RRC message, RRC parameter, and/or upper layer transmission of parameters), MAC control element (CE) signaling (e.g., transmission of MAC messages and/or MAC CE), or PHY signaling (e.g., downlink control information (DCI), uplink control information (UCI), and/or transmission of sidelink control information (SCI).

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

Referring to FIG. 1, the communication system 100 includes 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). A plurality of communication nodes are 4G communication (e.g., long term evolution (LTE), LTE-A (advanced)), 5G communication (e.g., new radio (NR)) specified in the 3GPP (3rd generation partnership project) standard. ), etc. can be supported. 4G communications can be performed in frequency bands below 6 GHz, and 5G communications can be performed in frequency bands above 6 GHz as well as below 6 GHz.

For example, for 4G communication and 5G communication, a plurality of communication nodes may use a communication protocol based on code division multiple access (CDMA), a communication protocol based on wideband CDMA (WCDMA), a communication protocol based on time division multiple access (TDMA), Communication protocol based on FDMA (frequency division multiple access), communication protocol based on OFDM (orthogonal frequency division multiplexing), communication protocol based on Filtered OFDM, communication protocol based on CP (cyclic prefix)-OFDM, DFT-s-OFDM (discrete Fourier transform-spread-OFDM)-based communication protocol, OFDMA (orthogonal frequency division multiple access)-based communication protocol, SC (single carrier)-FDMA-based communication protocol, NOMA (Non-orthogonal Multiple Access), GFDM (generalized frequency) division multiplexing)-based communication protocols, FBMC (filter bank multi-carrier)-based communication protocols, UFMC (universal filtered multi-carrier)-based communication protocols, and SDMA (Space Division Multiple Access)-based communication protocols. .

Additionally, the communication system 100 may further include a core network. If the communication system 100 supports 4G communication, the core network is S-GW (serving-gateway). It may include P-GW (packet data network (PDN)-gateway), MME (mobility management entity), etc. When the communication system 100 supports 5G communication, the core network may include a user plane function (UPF), a session management function (SMF), and an access and mobility management function (AMF).

Meanwhile, a plurality of communication nodes (110-1, 110-2, 110-3, 120-1, 120-2, 130-1, 130-2, 130-3, 130-) constituting the communication system 100 4, 130-5, 130-6) Each can have the following structure.

Figure 2 is a block diagram showing an 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 transmitting and receiving device 230 that is connected to a network and performs communication. Additionally, the communication node 200 may further include an input interface device 240, an output interface device 250, a storage device 260, etc. Each component included in the communication node 200 is connected by a bus 270 and can communicate with each other.

However, each component included in the communication node 200 may be connected through an individual interface or individual bus centered on the processor 210, rather than the common bus 270. For example, the processor 210 may be connected to at least one of the memory 220, the transmission/reception device 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 refer to 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 comprised of at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory 220 may be comprised of at least one of read only memory (ROM) and random access memory (RAM).

Referring again to FIG. 1, the communication system 100 includes a plurality of base stations (110-1, 110-2, 110-3, 120-1, 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. there is. 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 NB (NodeB), eNB (evolved NodeB), gNB, ABS (advanced base station), and HR. -High reliability-base station (BS), base transceiver station (BTS), radio base station, radio transceiver, access point, access node, radio access station (RAS) ), 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), radio remote head (RRH), transmission point (TP), transmission and reception point (TRP), etc.

Each of the plurality of terminals 130-1, 130-2, 130-3, 130-4, 130-5, and 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, mobile It may be referred to as a portable subscriber station, a node, a device, an on board unit (OBU), etc.

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, 120-2) transmits the signal received from the core network to the corresponding terminal (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 sent to the core network can be transmitted to.

In addition, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 performs MIMO transmission (e.g., single user (SU)-MIMO, multi user (MU)- MIMO, massive MIMO, etc.), coordinated multipoint (CoMP) transmission, carrier aggregation (CA) transmission, transmission in an unlicensed band, device to device communication (D2D) (or , ProSe (proximity services), IoT (Internet of Things) communication, dual connectivity (DC), etc. Here, each of the plurality of terminals 130-1, 130-2, 130-3, 130-4, 130-5, and 130-6 is connected to a base station 110-1, 110-2, 110-3, and 120-1. , 120-2) and operations corresponding to those supported by the base stations 110-1, 110-2, 110-3, 120-1, and 120-2. 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 to the fourth terminal 130-4 based on the SU-MIMO method. A signal can 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 method, and the fourth terminal 130-4 and the fifth terminal 130-5 can each 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 terminal 130-4 may transmit a signal to the fourth terminal 130-4. The terminal 130-4 can receive signals from the first base station 110-1, the second base station 110-2, and the third base station 110-3 using the CoMP method. Each of a plurality of base stations (110-1, 110-2, 110-3, 120-1, 120-2) has a terminal (130-1, 130-2, 130-3, 130-4) within its cell coverage. , 130-5, 130-6), and signals can be transmitted and received based on the CA method. The first base station 110-1, the second base station 110-2, and the third base station 110-3 each control 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 can perform D2D under the control of each of the second base station 110-2 and the third base station 110-3. .

Figure 3 is a graph to explain additional loss according to antenna beam width.

Referring to FIG. 3, a graph for explaining additional loss according to antenna beam width may be a graph showing additional power loss according to reception antenna beam width from actually measured data. In FIG. 3, the above two graphs can confirm the influence on the beam width in the azimuth (AZ) direction and the elevation (EL) direction when in the line of sight (LoS) area. And in the two graphs below in FIG. 3, you can see the effect on the beam width in the nonline of sight (NLoS) area. According to the example in FIG. 3, it can be seen that in the case of LoS, the elevation direction has a large influence, and in the case of NLoS, the azimuth angle has a significant influence.

Figure 4 is a conceptual diagram for explaining sequential beamforming in a base station.

Referring to FIG. 4, the base station 410 may sequentially perform beamforming in various directions for beam direction search or tracking. The base station 410 may sequentially perform beamforming using a plurality of beams 411-b1, 411-b2, 411-b3, 411-b4, and 411-b5 on the first side, and on the second side Beamforming can be performed sequentially using a plurality of beams 412-b1, 412-b2, 412-b3, 412-b4, and 412-b5, and a plurality of beams 413-b1, Beamforming can be performed sequentially using 413-b2, 413-b3, 413-b4, and 413-b5).

Meanwhile, link status (LoS, NLoS, etc.) may not be considered when determining order in the sequential direction, and in some cases, significant delays may occur in beam direction search and tracking. Therefore, it may take a long time until the loss of a link or the formation of a link is confirmed.

Next, a beam direction search device through recognition of link status will be explained.

Figure 5 is a block diagram showing an embodiment of a beam direction search device through link state recognition.

Referring to FIG. 5 , the beam direction search device 500 may include a link state recognition device 510, a beam direction control device 520, and a received power measurement device 530. Information about link status (LoS/NLoS, etc.) may be input from the link status recognition device 510 to the beam direction control device 520. When receiving link state information from the link state recognition device 510, the beam direction control device 520 searches for a beam in the azimuth direction or in the elevation direction depending on the link state (LoS/NLoS, etc.). You can decide whether to explore. The received power measurement device 530 may measure received power from the beam search direction (eg, azimuth direction, elevation direction) determined by the beam direction control device 520. Here, the received power is based on the received reference signal, such as signal to noise ratio (SNR), received signal strength indication (RSSI), reference signal received power (RSRP), and reference signal. It may be at least one of reception quality (RSRQ). At this time, the reference signal is a channel state information reference signal (CSI-RS), a demodulation reference signal (DM-RS), a phase tracking reference signal (PT-RS), It may include a sounding reference signal (SRS), etc. The received power value measured by the received power measurement device 530 may be referred to as received signal strength. The beam direction control device 520 may further include a storage device (not shown) that stores the received power from the received power measurement device 530.

The link state recognition device 510 can recognize the link state as LoS by using whether the direct wave is peaked or whether there is diffuse scattering. If the link is not initially established, the link state recognition device 510 can predict channel response characteristics from a pilot signal, and link states (LoS/NLoS, etc.) from a model predicting the channel response characteristics. ) can be estimated.

When information on link status (LoS/NLoS, etc.) is input, the beam direction control device 520 can determine whether to search in the azimuth or elevation direction depending on the link status. The beam direction control device 520 can control the determined beam direction and monitor received power to determine whether beam direction search has been performed or not. The beam direction control device 520 may perform beam direction search by changing the beam direction until the beam direction search is completed. Here, in the case of LoS, link state recognition can be determined based on whether a direct wave peaks or there is diffuse scattering, as an example. If the link is not initially established, the link state can be estimated from a model that predicts channel response characteristics from pilot signals. When a link is initially established, the link state can be determined based on a reference signal.

The received power measurement device 530 may measure at least one of SNR, RSSI, RSRP, and RSRQ based on the received reference signal. Reference signals may include CSI-RS, DM-RS, PT-RS, SRS, etc. Additionally, a synchronization signal may be used instead of a reference signal. The synchronization signal may be a primary synchronization signal (PSS), secondary synchronization signal (SSS), and/or a synchronization signal/physical broadcast channel (SS/PBCH) block. .

Next, the operation method of the beam direction search device 500 shown in FIG. 5 will be explained. The beam direction search device 500 may be included in a terminal, base station, etc. in a communication system.

Figure 6 is a flowchart showing an embodiment of a beam direction search device through link state recognition.

Referring to FIG. 6, an embodiment of the beam direction search device through link state recognition includes a link state recognition device 610, a beam direction control device 620, a received power measurement device 630, and a beam device 640. It can be included. The link state recognition device 610 can recognize link states (LoS/NLoS, etc.). The beam direction control device 620 can determine the beam direction in the azimuth or elevation direction depending on the link status (LoS/NLoS, etc.), and can perform beam direction search and control through received power monitoring. The received power measurement device 630 can measure received power for the beam(s) received from the beam device 640. The link state recognition device 610 may be the link state recognition device 510 in the beam direction search device 500 shown in FIG. 5, and the beam direction control device 620 may be the beam direction search device 500 shown in FIG. 5. The device 500 may be a beam direction control device 520, and the received power measurement device 630 may be a received power measurement device 530 in the beam direction search device 500 shown in FIG. 5 . The beam device 640 may be a device for explaining an embodiment of a beam direction search device through link state recognition, and may include a beam forming-based multiple antenna, an RF transmitting and receiving device, etc.

In step S610, the link state recognition device 610 may recognize a link state (LoS/NLoS, etc.), and the recognized link state may be provided as an input to the beam direction control device 620.

In step S620, the beam direction control device 620 may receive a link state (LoS/NLoS, etc.) from the link state recognition device 610 and determine a beam direction based on the link state. For example, if the input link state is confirmed to be LoS, the beam direction control device 620 may determine beam search in the elevation direction. On the other hand, if the input link state is confirmed to be NLoS, beam search can be determined in the azimuth direction.

In step S630, the beam direction control device 620 may instruct the beam device 640 to search in the beam direction determined in step S620.

In step S640, the received power measurement device 630 may measure received power using the beam received from the beam device 640. The beam direction control device 620 may monitor received power through the received power measurement device 530. The beam direction control device 620 may further include a storage device (not shown) that stores the received power from the received power measurement device 530.

In step S650, the beam direction control device 620 may monitor received power through the received power measurement device 630 to determine whether beam direction search has been performed or not. Additionally, the beam direction control device 620 may perform beam search by continuously changing the beam direction until the beam direction search is completed.

In step S660, the beam direction control device 620 may instruct the beam direction to be searched by the beam device 640 based on whether the beam direction is searched in step 650.

In step S670, the received power measuring device 630 may measure received power using the beam received from the beam device 640 with respect to the beam search direction indicated in step S660. The beam direction control device 620 may monitor received power through the received power measurement device 630.

Next, the beam direction search procedure based on link status ((LoS/NLoS, etc.) will be explained.

Figure 7 is a flowchart of a beam direction setting procedure through link status checking according to an embodiment of the present invention.

Referring to FIG. 7, the beam direction search apparatus may include a link state check step and determine the priority of beam direction search based on the link state (LoS/NLoS, etc.) confirmed in the link state check step. In other words, the beam direction search device can set different priorities for the azimuth direction and elevation direction depending on the link status (LoS/NLoS, etc.), and detects the beam direction more quickly depending on the link status (LoS/NLoS, etc.) to block. The maintenance of a continuous communication channel, etc., or the initial link setup delay time may be shortened. The beam direction setting procedure through link status confirmation can be applied to the terminal and base station, respectively. The beam direction search device may be the beam direction search device 500 shown in FIG. 5.

The direction finding device can check the link status (LoS/NLoS, etc.) based on the received signal strength of the signal received through beamforming (S710). For example, when the beam direction search device is applied to the terminal, the terminal determines the link status (LoS/NLoS, etc.) with the base station based on the received signal strength of the signal received by beamforming from the base station. ) can be confirmed. In addition, when the beam direction search device is applied to a base station, the base station can check the link status (LoS/NLoS, etc.) with the terminal based on the received signal strength received by beamforming from the terminal (S710). The received signal strength may be at least one of SNR, RSSI, RSRP, and RSRQ measured based on the received reference signal. Reference signals may include CSI-RS, DM-RS, PT-RS, SRS, etc. Additionally, a synchronization signal may be used instead of a reference signal.

The direction search device may perform a beam direction search procedure based on link status (LoS/NLoS, etc.). If the link state is confirmed to be line-of-sight (LoS) in step 710, the beam direction search device may set the priority of beam direction search in the order of elevation direction search and azimuth direction search. Based on the set priority, the step of searching the beam in the elevation direction can be sequentially performed (S720l), and the step of searching the beam in the azimuth direction can be performed (S730l).

If the link state (LoS/NLoS, etc.) is confirmed to be non-line-of-sight (NLoS) in step 710, the beam direction search device may set the priority of beam direction search in the order of azimuth direction search and elevation direction search. Based on the set priority, the step of searching the beam in the azimuth direction can be sequentially performed (S720n) and the step of searching the beam in the elevation direction can be performed (S730n).

Next, the hierarchical steps of beam direction search will be explained.

Figure 8 is a flowchart of hierarchical beam search in beam direction search according to an embodiment of the present invention.

Referring to FIG. 8, an embodiment of the hierarchical steps in beam direction search includes a coarse direction search step (S810) using a wide beam and a detailed search step (S810) using a narrow beam. A (fine) direction (narrow beam) search step (S820) may be included. Here, the rough direction (wide beam) search time can be shortened by performing a beam direction setting method through link status confirmation.

The operation of the method according to an embodiment of the present invention can be implemented as a computer-readable program or code on a computer-readable recording medium.　Computer-readable recording media include all types of recording devices that store information that can be read by a computer system.　Additionally, computer-readable recording media can be distributed across networked computer systems so that computer-readable programs or codes can be stored and executed in a distributed manner.

Additionally, computer-readable recording media may include hardware devices specially configured to store and execute program instructions, such as ROM, RAM, or flash memory.　Program instructions may include not only machine language code such as that created by a compiler, but also high-level language code that can be executed by a computer using an interpreter or the like.

Although some aspects of the invention have been described in the context of an apparatus, it may also refer to a corresponding method description, where a block or device corresponds to a method step or feature of a method step.　Similarly, aspects described in the context of a method may also be represented by corresponding blocks or items or features of a corresponding device.　Some or all of the method steps may be performed by (or using) a hardware device, such as, for example, a microprocessor, programmable computer, or electronic circuit.　In some embodiments, at least one or more of the most important method steps may be performed by such a device.

In embodiments, a programmable logic device (e.g., a field programmable gate array) may be used to perform some or all of the functionality of the methods described herein.　In embodiments, a field-programmable gate array may operate in conjunction with a microprocessor to perform one of the methods described herein.　In general, the methods are preferably performed by some hardware device.

Although the present invention has been described above with reference to preferred embodiments, those skilled in the art may make various modifications and changes to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. You will understand that it is possible.

Claims (1)

In the beam direction search method in the terminal,
Confirming the link status with the base station based on the received signal strength of a signal received by beamforming from the base station;
When the link state is line of sight (LoS), setting the priority of beam direction search in the order of azimuth (AZ) direction search and elevation (EL) direction search;
When the link state is none-line of sight (NLoS), setting the priority of beam direction search in the order of elevation (EL) direction search and azimuth (AZ) direction search; and
Comprising the step of sequentially searching beam directions based on the set priority,
Terminal beam direction search method.

Images