KR20220060480A - Method for configuring and managing beam in millimeter-wave communication system, and apparatus therefor - Google Patents

Abstract

The present invention relates to a method for configuring and managing a beam in a millimeter-wave communication system to help a base station use an optimal beam and an apparatus for the same. According to the present invention, a method of operating a base station to perform beam configuration and update comprises the following steps of: acquiring, by a scheduler, beam configuration data for each synchronization signal block (SSB) from a radio resource management (RRM) or operation, administration, and management (OAM) server outside a base station; requesting, by the scheduler, a physical layer to configure beams on the basis of the beam configuration data for each SSB and allowing the physical layer of the base station to transmit the SSBs corresponding to the beams on a one-to-one basis to the RRM on the basis of the beam configuration data for each SSB by an instruction; and receiving reference signal received power (RSRP) or signal to interference and noise ratios (SINRs) for the SSBs reported from a terminal and updating a beam database for each cell and/or the beam database for each terminal on the basis of the reported RSRP or SINRs.

Description

{Method for configuring and managing beam in millimeter-wave communication system, and apparatus therefor}

The present invention relates to a millimeter wave communication system, and more particularly, to a method for setting and managing a beam in a millimeter wave communication system, and an apparatus therefor.

Interest in the millimeter wave (mmWave) band is growing because of the huge spectrum available. However, the millimeter wave band suffers from high attenuation and propagation losses. In order to increase the transmission rate in the millimeter band, beamforming technology using multiple antennas is adopted, and unlike the 4G LTE system in the 5G NR system, the initial access/random access procedure, the paging procedure, A beam management technique is used in all procedures, such as a data/control information transmission/reception procedure, and a mobility handling procedure.

When such a beam management technique is not properly performed, the UE determines beam failure and performs a recovery procedure through a link error procedure, or when link errors accumulate, RRC connection re-establishment (re-establishment) ) to carry out the procedure. Accordingly, there may be a problem in that data transmission/reception is interrupted while the procedure is being performed.

In addition, the beam management technology in the 5G NR system should be designed to use a plurality of tunable beams, and to overcome the large path loss, each beam can focus on a specific part of a cell to transmit a signal while Beams must be designed to cover cell coverage. Therefore, the beam management technique should be operated so that the optimal beam direction is selected in consideration of the number of synchronization signal blocks (SSBs), the width of each beam, the universal location of the terminal, etc. according to the base station installation environment.

An object of the present invention to solve the above problems is to provide a method for setting and managing a beam that can be applied to a millimeter wave communication system.

Another object of the present invention to solve the above problems is to provide an apparatus to which a beam setting and management method applicable to a millimeter wave communication system is applied.

An embodiment of the present invention for achieving the above object is an operating method of a base station for performing beam configuration and update, wherein a scheduler performs radio resource management (RRM) or operation, administration, and management (OAM) outside the base station acquiring beam configuration data for each synchronization signal block (SSB) from a server; The scheduler requests the physical layer to set the beams based on the beam configuration data for each SSB, and according to the RRM, the physical layer of the base station corresponds to the beams on the basis of the beam configuration data for each SSB one-to-one. causing SSBs to be transmitted; and receiving RSRP or SINRs for the SSBs from the UE, and updating the beam database for each cell and/or the beam database for each UE based on the reported RSRP or SINRs.

Here, based on the beam database for each cell, among the SSBs, the SSB(s) to be transmitted, the SSB(s) to be removed, or the SSB(s) to which the corresponding beam(s) should be changed may be determined.

Here, based on the beam database for each terminal, whether to start a beam update procedure with the terminal may be determined.

Embodiments of the present invention may provide a method for efficiently performing beam configuration and management of a millimeter wave base station. When allocating beams for SSBs according to the base station installation environment, a beam map, which is a database indicating the relative positions to which beams are allocated for each SSB, is built, and based on the constructed beam map, RSRP reported by the terminal or In the process of selecting a beam by receiving the SINR, more reliable beams may be selected. In addition, while the terminal is connected, it manages the beam selection data and periodically or aperiodically transmits statistical data to the upper layer to help the corresponding base station use the optimal beam in consideration of the distribution of terminals for each beam. .

1A to 1C are conceptual diagrams for explaining various examples of setting beams applied to embodiments of the present invention.
2A and 2B are simplified flowcharts for explaining a procedure for performing beam setting according to embodiments of the present invention.
3 is a simplified flowchart for explaining a procedure for performing beam management (updating) according to embodiments of the present invention.
4 is a conceptual diagram for explaining the configuration of a communication node according to an embodiment of the present invention.

Since the present invention can have various changes and can have various embodiments, specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention. In describing each figure, like reference numerals have been used for like elements.

Terms such as first, second, A, and B 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 an element is referred to as being “connected” or “connected” to another element, it is understood that it may be directly connected or connected to the other element, but other elements 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 should be understood that this does not preclude the existence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical and 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 commonly used dictionaries 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

A communication system to which embodiments according to the present invention are applied will be described. The communication system to which the embodiments according to the present invention are applied is not limited to the content 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 sense as a communication network (network).

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.

In the 5G NR system, synchronization signal blocks (SSB) composed of a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcast channel (PBCH) are used for basic beam operation. In the LTE system, the synchronization signal is transmitted once every 5 ms, but in the 5G NR system, multiple SSBs are transmitted through different transmission beams within 5 msec time. The UE detects the beam assuming that the SSB is transmitted every 20 msec when viewed as a reference to one specific beam used for transmission. Here, a transmission period of 20 msec is a period applied to a stand-alone (SA) terminal, and in the case of a non-stand-alone (NSA) terminal, the base station may inform the terminal of the transmission period of the SSB.

The number of beams used to transmit SSBs within 5 msec time may vary according to a frequency band. Specifically, the higher the frequency band, the greater the number of beams may be used. For example, in a band of 3 GHz or less, up to 4 SSBs can be transmitted through different beams within 5 msec time, and in a band from 3 GHz to 6 GHz, up to 8 SSBs can be transmitted through different beams within 5 msec time, In a band of 6 GHz or higher, up to 64 SSBs can be transmitted through different beams.

In the 5G NR system, the initial access procedure between the base station and the terminal may be performed as follows. The base station may perform a beam sweeping procedure for sequentially transmitting SSBs to different beams, and the terminal may measure the reference signal received power (RSRP) of the received SSB to select the most optimal RSRP received SSB. can By transmitting a preamble using a random access channel resource associated with the selected SSB, the terminal informs the base station of information on which beam to transmit/receive through. Thereafter, the terminal transmits and receives data using the beam used to receive the SSB selected in the initial access process, and the base station uses the beam used to transmit the SSB connected to the resource of the preamble transmitted by the terminal in the initial access process. transmission and reception of

Since the optimal beam may be changed for reasons such as movement of the terminal, the base station can be configured to periodically or aperiodically measure and report the RSRP or SINR (signal to interference and noise ratio) of the SSB (CSI-Reporting). . The UE selects the N SSBs having the highest RSRP or SINR among the received SSBs and reports the RSRP or SINRs of the selected SSBs to the base station periodically or aperiodically, and the base station reports the RSRP or SINRs of the SSBs reported by the UE to the base station. Thus, it is determined whether to change the transmit/receive beams.

Beam setting for each SSB according to the base station installation environment may be performed by an organization and management (OAM) server that manages the operation and management of base stations or RRM (radio resource management), which is an internal radio resource management protocol of the base station. Therefore, it is possible to set up various types of beams for each SSB according to the installation location and environment of the base station.

1A to 1C are conceptual views for explaining various examples of setting beams applied to embodiments of the present invention.

1A shows the configuration of beams (ie, SSBs) that can be considered when the base station is installed at a height of 2 m or more from the ground and the antennas are down-tilting toward the ground, and FIG. 1b shows the configuration of beams (ie, SSBs) viewed from the front of the base station when the base station is installed at a height similar to that of the terminal. FIG. 1C illustrates a configuration of beams (ie, SSBs) that can be considered when a base station is installed on the ceiling of an indoor space and faces the floor.

The above-described examples are merely examples for convenience of description, and beams may be set in various shapes according to the installation location of the base station, the type and direction of the antenna installed in the base station, and the shape of the space in which the base station is installed. Hereinafter, the installation location of the base station, the type and direction of the antenna installed in the base station, and the shape of the space in which the base station is installed are collectively defined as the 'environment' of the corresponding base station.

2A and 2B are simplified flowcharts for explaining a procedure for performing beam setting according to embodiments of the present invention.

The procedure shown in FIG. 2A corresponds to a procedure in which the OAM server performs beam setting, and in the procedure shown in FIG. 2B, the base station (ie, RRM of the base station) takes the initiative in beam setting based on information provided by the OAM server. It is applicable to the procedure to carry out

That is, in the procedure shown in FIG. 2A , the OAM server 210 generates SSB/beam configuration data (beam configuration data for each SSB) according to the environment of the base station 220 ( S210 ). When the base station 220 requests the configuration of cells, the generated SSB/beam configuration data may be transmitted to the base station 220 (S211). On the other hand, in the procedure shown in FIG. 2B, the OAM server 210 sets the cell location information to the base station (ie, the RRM of the base station) so that the base station 200 can select the optimal beam setting from among the preset beam settings. can be transmitted when requested (S220). The RRM 223 of the base station 210 may receive the location information, and based on the location information, select one of the beam setups preset in the base station to perform cell setup ( S221 ). That is, the RRM 223 may select the optimal SSB/beam configuration data from among the SSB/beam configuration data preset by the base station based on the location information provided by the OAM server 210 .

The subsequent steps ( S220 to S260 ) may be commonly performed with respect to the procedures shown in FIGS. 2A and 2B .

The RRM 223 may request beam configuration from the physical layer 221 of the base station, and may transmit beam configuration data to the physical layer 221 ( S230 ). In this case, the beam configuration data may define a beam identifier (beamId) for each vertical/horizontal polarization to be used in a cell and a gain/phase of antennas corresponding to each beam identifier. The RRM 223 may transmit beam configuration data to the physical layer 221 , and the physical layer 221 of the base station may be configured based on the transmitted beam configuration data. Next, the OAM server 230 or the RRM 223 may request the configuration of cells while providing the cell configuration information to the scheduler 222 (S240), and the scheduler 222 may send the RRM 223 to the RRM 223. ) may transmit a response to each cell setting to the OAM server 230 (S241, S242).

In this case, the cell configuration information (beam configuration information for each SSB) provided to the scheduler 222 may be configured as shown in Table 1 below.

Referring to Table 1, cell configuration information includes information on beamId (ie, a vertical polarization beam index and a horizontal polarization beam index) corresponding to each SSB and the number of beams (SSBs) neighboring the beam for each SSB (nrOfneighborSSBs) and information (neigbor_ssbindex) on indices of neighboring SSBs may be further included. The information may be used in a procedure in which the UE reports RSRP or SINR for each SSB and replaces the beam.

For example, referring back to FIG. 1A , if only immediately adjacent SSBs are configured as neighboring SSBs for SSB 6, the indices of neighboring SSBs for SSB 6 are 8, {2, 3, 5, 7, 10 , 11, 12, 13}. On the other hand, if not only adjacent SSBs but also the next adjacent SSBs are included as the neighboring SSBs for SSB 16, the indices of the neighboring SSBs for SSB 16 are 5 in total, {8, 15}, {4, 7, 14} can be set to

In addition, in the cell configuration information, each SSB is multiplied by a weight (weight_base), and a weight set for the neighboring SSBs is multiplied, so that the RSRPs or SINRs reported for the SSBs can be filtered. there is. For example, if the weight (weight_base) of the current SSB is 1024 and the weights of the neighboring SSBs are all 1024, the effect of equally filtering with the same weight can be obtained. As an example of setting the weight differently, when setting information on SSB 16 in FIG. 1A , the weight is set to 1024 for immediately adjacent SSBs (ie, indexes {8, 15}), and then the next adjacent SSBs (ie, indexes) {4, 7, 14}), by setting the weight to 1000, it is possible to reflect the differential weights when filtering the reported RSRP or SINR. Such filtering will be described later in a beam management method according to an embodiment of the present invention, which will be described later with reference to FIG. 3 .

Next, the OAM server 210 requests the RRM 223 to start the cells configured through the above-described steps (S250), and the RRM 223 transmits the request to the scheduler 222 (S251), and the scheduler 222 may instruct the physical layer 221 to transmit SSBs (S252). A response to the cell start request may be transmitted from the scheduler 222 to the RRM 223 and from the RRM 223 to the OAM server 210 (S253, S254).

When the cell configuration is completed and the cell is started, the base station transmits SSBs using different beams (S260). The terminal 230 receives them, selects an SSB corresponding to the best RSRP, and transmits a preamble using a random access channel resource connected thereto, thereby informing the base station of information on which beam to transmit and receive. This is an RRC connection procedure of the UE, and detailed description thereof will be omitted.

3 is a simplified flowchart for explaining a procedure for performing beam management (updating) according to embodiments of the present invention.

While establishing the RRC connection with the UE or after completing the establishment of the RRC connection with the UE, the base station may configure the UE to perform SSB-RSRP or SSB-SINR reporting as CSI-Reporting configuration (S310). The UE may perform SSB-RSRP or SSB-SINR measurement in the CSI-Reporting configuration (S321). The SSB-RSRP/SSB-SINR report is received in the physical layer 221 through a PUCCH or PUSCH channel in a layer 1 procedure (S322), and may be reported to the scheduler 222 (S323).

The scheduler 222 may update the RSRP or SINR reported for each SSB to a beam database managed for each cell and a beam database managed for each UE (S324).

In this case, the beam database managed for each cell may be configured as shown in Table 2 below. The beam database managed for each cell is for judging whether the SSBs configured at the time of initial configuration of the cells are effectively used, and can be managed by updating all CSI reporting of all terminals connected to each cell. The beam database managed for each cell may be periodically reported to the RRM 223 or the OAM server 210 . In the RRM 223 or the OAM server 210, based on the collected cell-by-cell beam database, which SSB(s) are the SSB(s) that are currently well utilized, the SSB(s) to keep and remove (ie, transmit) It is possible to determine which SSB(s) the SSB(s) to which the corresponding beam (to be stopped) is to be changed.

Meanwhile, the beam database managed by the scheduler 222 for each terminal may be configured as shown in Table 3 below. In the beam database for each terminal, the number of total reports (nrOfReports) reported for each terminal and filtering values of RSRP or SINR for each reported SSB index are stored. In this case, filtering may be performed by reflecting the given weights described in Table 1, and filtered RSRP or filtered SINR may be calculated through a method such as IR filtering or average filtering.

The scheduler 222 compares the measured values of the updated SSBs and, when it is necessary to select an SSB different from the beam corresponding to the currently transmitted/received SSB, it may determine the beam update (replacement) (S330). That is, when the SSB having the highest filtered RSRP or filtered SINR is not the SSB corresponding to the current transmission/reception beam, the scheduler 222 may perform a beam update procedure with the UE 230 (S340).

When the beam update procedure is completed, the scheduler 222 notifies the RRM 223 that the beam of the corresponding terminal is changed (S351), transmits the database of the terminal so that the RRM can store the beam path of the terminal, and then the terminal beam The database may be initialized (S353). The above-described process may be repeatedly performed while the terminal is connected.

The RRM 223 may receive a database from the scheduler 222 whenever a beam is changed for each terminal, and may convert it into path data and store it. The database is managed for each terminal from the time when the RRC connection with the terminal is established until the RRC connection is released, and when the RRC connection with the terminal is released or when the statistical data is reported to the OAM server 210 (S353), the database is connected Path data for all terminals that have been used may be reported by composing with Table 4 below.

The OAM server 210 may secure the mobility data of the terminal based on this, and furthermore, may construct basic data for efficiently managing beam arrangement and the like.

4 is a conceptual diagram for explaining the configuration of a communication node according to an embodiment of the present invention.

The communication node according to an embodiment of the present invention illustrated in FIG. 4 may be the above-described OAM server 210 , the base station 220 , or the terminal 230 .

Referring to FIG. 4 , the communication node 400 may include at least one processor 410 , a memory 420 , and a transceiver 430 connected to a network to perform communication. In addition, the communication node 400 may further include an input interface device 440 , an output interface device 450 , a storage device 460 , and the like. Each of the components included in the communication node 400 may be connected by a bus 470 to communicate with each other.

However, each of the components included in the communication node 400 may not be connected to the common bus 470 but to the processor 410 through an individual interface or an individual bus. For example, the processor 410 may be connected to at least one of the memory 420 , the transceiver 430 , the input interface device 440 , the output interface device 450 , and the storage device 460 through a dedicated interface. .

The processor 410 may execute a program command stored in at least one of the memory 420 and the storage device 460 . The processor 410 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 420 and the storage device 460 may be configured as at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory 420 may be configured as at least one of a read only memory (ROM) and a random access memory (RAM).

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, etc. 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 (1)

An operating method of a base station for performing beam setup and update, comprising:
acquiring, by a scheduler, beam configuration data for each synchronization signal block (SSB) from a radio resource management (RRM) or an operation, administration, and management (OAM) server outside the base station;
The scheduler requests the physical layer to set beams based on the beam configuration data for each SSB, and according to the RRM, the physical layer of the base station performs a one-to-one correspondence with the beams based on the beam configuration data for each SSB. causing SSBs to be transmitted; and
Receiving RSRP or SINRs for the SSBs from the UE, and updating a beam database for each cell and/or a beam database for each UE based on the reported RSRP or SINRs,
SSB(s) for which transmission is to be maintained, SSB(s) to be removed, or SSB(s) to which a corresponding beam(s) is to be changed among the SSBs is determined based on the beam database for each cell, and for each terminal It is determined whether to start a beam update procedure with the terminal based on the beam database,
How the base station works.

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