WO2018097416A1

WO2018097416A1 - Device and method for detecting beam misalignment in wireless communication system

Info

Publication number: WO2018097416A1
Application number: PCT/KR2017/002758
Authority: WO
Inventors: 정도영; 손이빈; 문정민; 백인길; 정준희
Original assignee: 삼성전자주식회사
Priority date: 2016-11-28
Filing date: 2017-03-14
Publication date: 2018-05-31
Also published as: CN116346186A

Abstract

Disclosed is a fifth generation (5G) or pre-5G communication system for supporting a data transmission rate higher than that of a fourth generation (4G) communication system such as long term evolution (LTE). The purpose of the disclosure is to detect beam misalignment in a wireless communication system, and a terminal operation method comprises the steps of: receiving multiple reference signals for a first period; receiving multiple reference signals for a second period; and determining whether a beam is misaligned, on the basis of a first measurement value set for the multiple reference signals received for the first period and a second measurement value set for the multiple reference signals received for the second period. The study has been performed under the support of the "Government-wide Giga KOREA Business" of the Ministry of Science, ICT and Future Planning.

Description

Apparatus and method for detecting beam mismatch in wireless communication system

The present disclosure generally relates to a wireless communication system, and more particularly, to an apparatus and method for detecting beam misalignment in a wireless communication system.

This study was supported by the Ministry of Science, ICT and Future Planning 'Giga KOREA Project'.

4G (4 ^th generation) to meet the traffic demand in the radio data communication system increases since the commercialization trend, efforts to develop improved 5G (5 ^th generation) communication system, or pre-5G communication system have been made. For this reason, a 5G communication system or a pre-5G communication system is called a Beyond 4G Network communication system or a Long Term Evolution (LTE) system (Post LTE) system.

In order to achieve high data rates, 5G communication systems are being considered for implementation in the ultra-high frequency (mmWave) band (eg, such as the 60 Gigabit (60 GHz) band). In order to mitigate the path loss of radio waves and increase the propagation distance of radio waves in the ultra-high frequency band, beamforming, massive array multiple input / output (Full-Dimensional MIMO, FD-MIMO) in 5G communication systems Array antenna, analog beam-forming, and large scale antenna techniques are discussed.

In addition, in order to improve the network of the system, 5G communication system has evolved small cells, advanced small cells, cloud radio access network (cloud RAN), ultra-dense network (ultra-dense network) , Device to device communication (D2D), wireless backhaul, moving network, cooperative communication, coordinated multi-points (CoMP), and interference cancellation The development of such technology is being done.

In addition, in 5G systems, Hybrid Frequency Shift Keying and Quadrature Amplitude Modulation (FQAM) and sliding window superposition coding (SWSC), Advanced Coding Modulation (ACM), and Filter Bank Multi Carrier (FBMC), an advanced access technology ), Non Orthogonal Multiple Access (NOMA), Spar Code Multiple Access (SCMA), and the like are being developed.

Based on the discussion as described above, the present disclosure provides an apparatus and method for effectively performing beamforming in a wireless communication system.

The present disclosure also provides an apparatus and method for using the best beam in a wireless communication system.

The present disclosure also provides an apparatus and method for detecting beam misalignment in a wireless communication system.

The present disclosure also provides an apparatus and method for resolving a beam mismatch situation in a wireless communication system.

The present disclosure also provides an apparatus and method for triggering intensive reference signal transmission for beam search in a wireless communication system.

The present disclosure also provides an apparatus and method for determining a serving beam based on a measurement pattern of transmission beams in a wireless communication system.

The present disclosure also provides an apparatus and method for determining a serving beam based on measured values of a sensor in a wireless communication system.

According to various embodiments of the present disclosure, a method of operating a terminal in a wireless communication system may include: receiving a plurality of reference signals during a first period; receiving a plurality of reference signals during a second period; Determining whether there is a beam mismatch based on a first set of measurement values for the plurality of reference signals received during the period and a second set of measurement values for the plurality of reference signals received during the second period.

According to various embodiments of the present disclosure, a method of operating a terminal in a wireless communication system may include: activating a receiving circuit to receive a signal during an on duration of a discontinuous operation mode, and a sleep; ) When the interval arrives, activating the reception circuit, activating the reception circuit to detect a beam mismatch after the first portion of the sleep interval elapses, and when the beam mismatch occurs, the sleep interval Activating the receiving circuit to recover the beam during the second portion of the circuit.

According to various embodiments of the present disclosure, in a wireless communication system, a terminal device may include a receiver configured to receive a plurality of reference signals during a first period and receive a plurality of reference signals during a second period, and received during the first period. And a controller for determining whether there is a beam mismatch based on a first set of measurement values for the plurality of reference signals and a second set of measurement values for the plurality of reference signals received during the second period.

According to various embodiments of the present disclosure, a terminal device in a wireless communication system includes a receiver including a receiver circuit selectively activated during a discontinuous operation mode, and a controller controlling the receiver circuit. Here, the control unit, during the on period of the discontinuous operation mode, to receive a signal, to activate the receiving circuit, when the sleep period arrives, deactivate the receiving circuit, after the first portion of the sleep period, Activate the receiving circuit to detect beam mismatch, and if the beam mismatch occurs, activate the receiving circuit to recover the beam during the second portion of the sleep period.

Apparatus and method according to various embodiments of the present disclosure enable more accurate determination of beam mismatch by detecting beam mismatch using measurement results for multiple beams.

Effects obtained in the present disclosure are not limited to the above-mentioned effects, and other effects not mentioned above may be clearly understood by those skilled in the art from the following description. will be.

1 illustrates a wireless communication system according to various embodiments of the present disclosure.

2 illustrates a configuration of a base station in a wireless communication system according to various embodiments of the present disclosure.

3 illustrates a configuration of a terminal in a wireless communication system according to various embodiments of the present disclosure.

4A to 4C illustrate a configuration of a communication unit in a wireless communication system according to various embodiments of the present disclosure.

5 illustrates a situation in which beam misalignment occurs in a wireless communication system according to various embodiments of the present disclosure.

6 illustrates a method of operating a terminal in a wireless communication system according to various embodiments of the present disclosure.

7A illustrates an operation method for beam mismatch detection based on a measurement pattern in a wireless communication system according to various embodiments of the present disclosure.

7B illustrates an example of beam mismatch detection based on a measurement pattern in a wireless communication system according to various embodiments of the present disclosure.

8A illustrates an operation method for beam mismatch detection based on an order of measurement values in a wireless communication system according to various embodiments of the present disclosure.

8B illustrates an example of beam mismatch detection based on the order of measurement values in a wireless communication system according to various embodiments of the present disclosure.

8C illustrates another example of beam mismatch detection based on the order of measurement values in a wireless communication system according to various embodiments of the present disclosure.

8D illustrates a method of operation for grouping measured values in a wireless communication system according to various embodiments of the present disclosure.

8E illustrates an example of beam mismatch detection based on an order of a group of measurement values in a wireless communication system according to various embodiments of the present disclosure.

9 illustrates a state transition diagram related to beam mismatch in a wireless communication system according to various embodiments of the present disclosure.

10A illustrates an operation method for power control based on beam mismatch detection in a wireless communication system according to various embodiments of the present disclosure.

10B and 10C illustrate examples of power control based on beam mismatch detection in a wireless communication system according to various embodiments of the present disclosure.

11A and 11B illustrate transmission schemes of reference signals supported in a wireless communication system according to various embodiments of the present disclosure.

11C illustrates signal exchange for a beam recovery procedure using intensive reference signal transmission in a wireless communication system according to various embodiments of the present disclosure.

12A illustrates an operation method for recovering a beam using previous measurement results in a wireless communication system according to various embodiments of the present disclosure.

12B illustrates an operation method for recovering a beam using a previous measurement or using a new measurement in a wireless communication system according to various embodiments of the present disclosure.

12C illustrates an example of beam recovery using previous measurement results in a wireless communication system according to various embodiments of the present disclosure.

13A illustrates an operation method for recovering a beam using sensor values in a wireless communication system according to various embodiments of the present disclosure.

13B illustrates an example of a sensor value change according to movement in a wireless communication system according to various embodiments of the present disclosure.

13C and 13D illustrate examples of installation of a sensor in a wireless communication system according to various embodiments of the present disclosure.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the scope of other embodiments. Singular expressions may include plural expressions unless the context clearly indicates otherwise. The terms used herein, including technical or scientific terms, may have the same meaning as commonly understood by one of ordinary skill in the art as described in the present disclosure. Among the terms used in the present disclosure, terms defined in the general dictionary may be interpreted as having the same or similar meaning as the meaning in the context of the related art, and ideally or excessively formal meanings are not clearly defined in the present disclosure. Not interpreted as In some cases, even if terms are defined in the present disclosure, they may not be interpreted to exclude embodiments of the present disclosure.

In various embodiments of the present disclosure described below, a hardware approach will be described as an example. However, various embodiments of the present disclosure include a technology using both hardware and software, and thus various embodiments of the present disclosure do not exclude a software-based approach.

The present disclosure relates to an apparatus and method for detecting beam misalignment in a wireless communication system. The present disclosure also relates to an apparatus and method for recovering a beam upon beam mismatch in a wireless communication system.

Terms used to describe signals used in the following description, terms referring to channels, terms referring to control information, terms referring to network entities, terms referring to components of devices, and the like are provided for convenience of description. It is illustrated. Thus, the present disclosure is not limited to the terms described below, and other terms having equivalent technical meanings may be used.

In addition, the present disclosure describes various embodiments using terms used in some communication standards (eg, long term evolution (LTE) system and LTE-advanced (LTE-A)), but this is only an example for description. . Various embodiments of the present disclosure may be easily modified and applied to other communication systems.

1 illustrates a wireless communication system according to various embodiments of the present disclosure. FIG. 1 illustrates a base station 110, a terminal 120, and a terminal 130 as part of nodes using a wireless channel in a wireless communication system.

Base station 110 is a network infrastructure that provides wireless access to

terminals

120 and 130. The base station 110 has coverage defined as a certain geographic area based on the distance over which the signal can be transmitted. In addition to the base station, the base station 110 includes an 'access point (AP)', 'eNodeB (eNB)', '5G generation node', 'wireless point', ' Transmission / reception point (TRP) ”and the like.

Each of the terminal 120 and the terminal 130 is a device used by a user and communicates with the base station 110 through a wireless channel. In some cases, at least one of the terminal 120 and the terminal 130 is a device for performing machine type communication (MTC) and may not be carried by a user. Each of the terminal 120 and the terminal 130 is a terminal other than a user equipment (UE), a mobile station, a subscriber station, a remote terminal, and a remote terminal. Wireless terminal ', or' user device 'or the like.

The base station 110, the terminal 120, and the terminal 130 may transmit and receive a radio signal in a millimeter wave (mmWave) band (eg, 28 GHz, 30 GHz, 60 GHz). In this case, in order to improve the channel gain, the base station 110, the terminal 120, and the terminal 130 may perform beamforming. Here, beamforming includes transmit beamforming and receive beamforming. That is, the base station 110, the terminal 120, and the terminal 130 may give directivity to a transmission signal or a reception signal. To this end, the base station 110 and the

terminals

120 and 130 may select the serving

beams

112, 113, 121, and 131 through a beam search procedure.

2 illustrates a configuration of a base station in a wireless communication system according to various embodiments of the present disclosure. Used below '… Wealth, The term 'herein' refers to a unit for processing at least one function or operation, which may be implemented by hardware or software, or a combination of hardware and software.

Referring to FIG. 2, the base station 110 includes a wireless communication unit 210, a backhaul communication unit 220, a storage unit 230, and a control unit 240.

The wireless communication unit 210 performs functions for transmitting and receiving a signal through a wireless channel. For example, the wireless communication unit 210 performs a baseband signal and bit string conversion function according to the physical layer standard of the system. For example, during data transmission, the wireless communication unit 210 generates complex symbols by encoding and modulating a transmission bit string. In addition, when receiving data, the wireless communication unit 210 restores the received bit string by demodulating and decoding the baseband signal. In addition, the wireless communication unit 210 up-converts the baseband signal into a radio frequency (RF) band signal, transmits the signal through an antenna, and downconverts the RF band signal received through the antenna into a baseband signal.

To this end, the wireless communication unit 210 may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a digital to analog convertor (DAC), an analog to digital convertor (ADC), and the like. In addition, the wireless communication unit 210 may include a plurality of transmission and reception paths. Furthermore, the wireless communication unit 210 may include at least one antenna array composed of a plurality of antenna elements. In terms of hardware, the wireless communication unit 210 may be composed of a digital unit and an analog unit, and the analog unit may include a plurality of sub-units according to operating power, operating frequency, and the like. It can be configured as.

The wireless communication unit 210 transmits and receives a signal as described above. Accordingly, the wireless communication unit 210 may be referred to as a 'transmitter', 'receiver' or 'transceiver'. In addition, in the following description, transmission and reception performed through a wireless channel are used to mean that the processing as described above is performed by the wireless communication unit 210.

The backhaul communication unit 220 provides an interface for communicating with other nodes in the network. That is, the backhaul communication unit 220 converts a bit string transmitted from another base station 110 to another node, for example, another access node, another base station, an upper node, a core network, etc. into a physical signal, and converts the physical signal received from the other node into a bit. Convert to heat

The storage unit 230 stores data such as a basic program, an application program, and setting information for the operation of the base station 110. The storage unit 230 may be configured as a volatile memory, a nonvolatile memory, or a combination of the volatile memory and the nonvolatile memory. The storage unit 230 provides the stored data at the request of the controller 240.

The controller 240 controls overall operations of the base station. For example, the controller 240 transmits and receives a signal through the wireless communication unit 210 or through the backhaul communication unit 220. In addition, the controller 240 records and reads data in the storage 230. To this end, the controller 240 may include at least one processor. For example, the controller 240 may control the base station 110 to perform operations according to various embodiments described below.

3 illustrates a configuration of a terminal in a wireless communication system according to various embodiments of the present disclosure. Used below '… Wealth, The term 'herein' refers to a unit for processing at least one function or operation, which may be implemented by hardware or software, or a combination of hardware and software.

Referring to FIG. 3, the terminal 120 includes a communication unit 310, a storage unit 320, and a control unit 330.

The communication unit 310 performs functions for transmitting and receiving a signal through a wireless channel. For example, the communicator 310 performs a conversion function between the baseband signal and the bit string according to the physical layer standard of the system. For example, during data transmission, the communication unit 310 generates complex symbols by encoding and modulating a transmission bit string. In addition, when receiving data, the communication unit 310 restores the received bit string by demodulating and decoding the baseband signal. In addition, the communication unit 310 up-converts the baseband signal to an RF band signal and then transmits the signal through an antenna and downconverts the RF band signal received through the antenna to the baseband signal. For example, the communication unit 310 may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, and the like.

In addition, the communication unit 310 may include a plurality of transmission and reception paths. Further, the communicator 310 may include at least one antenna array composed of a plurality of antenna elements. In terms of hardware, the wireless communication unit 210 may be composed of a digital circuit and an analog circuit (for example, radio frequency integrated circuit (RFIC)). Here, the digital circuit and the analog circuit can be implemented in one package. In addition, the communication unit 310 may include a plurality of RF chains. In addition, the communicator 310 may perform beamforming.

The communication unit 310 transmits and receives a signal as described above. Accordingly, the communication unit 310 may be referred to as a 'transmitter', 'receiver' or 'transceiver'. In addition, in the following description, transmission and reception performed through a wireless channel are used by the communication unit 310 to mean that the above-described processing is performed.

The storage 320 stores data such as a basic program, an application program, and setting information for the operation of the terminal 120. The storage unit 320 may be configured of a volatile memory, a nonvolatile memory, or a combination of the volatile memory and the nonvolatile memory. The storage 320 provides the stored data according to a request of the controller 330.

The controller 330 controls the overall operations of the terminal 120. For example, the controller 330 transmits and receives a signal through the communication unit 310. In addition, the controller 330 records and reads data in the storage 320. To this end, the controller 330 may include at least one processor or a micro processor, or may be part of a processor. In addition, a part of the communication unit 310 and the control unit 330 may be referred to as a communication processor (CP). In particular, the controller 330 controls the terminal 120 to detect a beam mismatch and to perform a beam recovery procedure according to various embodiments described below. For example, the controller 330 may control the terminal to perform operations according to various embodiments described below.

4A to 4C illustrate a configuration of a communication unit in a wireless communication system according to various embodiments of the present disclosure. 4A to 4C illustrate examples of detailed configurations of the communication unit 210 of FIG. 2 or the communication unit 210 of FIG. 3. Specifically, FIGS. 4A to 4C illustrate components for performing beamforming as part of the communication unit 210 of FIG. 2 or the communication unit 210 of FIG. 3.

Referring to FIG. 4A, the

communication unit

210 or 310 includes an encoding and modulation unit 402, a digital beamforming unit 404, a plurality of transmission paths 406-1 to 406 -N, and an analog beamforming unit 408.

The encoder and modulator 402 performs channel encoding. For channel encoding, at least one of a low density parity check (LDPC) code, a convolution code, and a polar code may be used. The encoder and modulator 402 generates modulation symbols by performing constellation mapping.

The digital beamforming unit 404 performs beamforming on a digital signal (eg, modulation symbols). To this end, the digital beamforming unit 404 multiplies the modulation symbols by beamforming weights. Here, the beamforming weights are used to change the magnitude and phase of the signal, and may be referred to as a 'precoding matrix', 'precoder', or the like. The digital beamforming unit 404 outputs the digital beamformed modulation symbols in the plurality of transmission paths 406-1 through 406-N. In this case, according to a multiple input multiple output (MIMO) transmission scheme, modulation symbols may be multiplexed, or the same modulation symbols may be provided in multiple transmission paths 406-1 to 406-N.

Multiple transmission paths 406-1 through 406-N convert digital beamformed digital signals into analog signals. To this end, each of the plurality of transmission paths 406-1 to 406 -N may include an inverse fast fourier transform (IFFT) calculator, a cyclic prefix (CP) inserter, a DAC, and an upconverter. The CP insertion unit is for an orthogonal frequency division multiplexing (OFDM) scheme and may be excluded when another physical layer scheme (for example, a filter bank multi-carrier (FBMC)) is applied. That is, the multiple transmission paths 406-1 through 406-N provide an independent signal processing process for multiple streams generated through digital beamforming. However, depending on the implementation manner, some of the components of the plurality of transmission paths 406-1 to 406-N may be used in common.

The analog beamforming unit 408 performs beamforming on the analog signal. To this end, the digital beamforming unit 404 multiplies the analog signals by beamforming weights. Here, beamforming weights are used to change the magnitude and phase of the signal. Specifically, according to the connection structure between the plurality of transmission paths 406-1 to 406-N and the antennas, the analog beamforming unit 408 may be configured as shown in FIG. 4B or 4C.

Referring to FIG. 4B, signals input to the analog beamforming unit 408 are transmitted through antennas through phase / magnitude conversion and amplification. At this time, the signal of each path is transmitted through different antenna sets, that is, antenna arrays. Looking at the processing of the signal input through the first path, the signal is converted into signal sequences having different or the same phase / magnitude by the phase / magnitude converters 412-1-1 through 412-1-M, and the amplifiers 414-. Amplified by 1-1 through 414-1-M, then transmitted via antennas.

Referring to FIG. 4C, signals input to the analog beamforming unit 408 are transmitted through antennas through phase / magnitude conversion and amplification. At this time, the signal of each path is transmitted through the same antenna set, that is, the antenna array. Looking at the processing of the signal input through the first path, the signal is converted into signal sequences having different or the same phase / magnitude by the phase / magnitude converters 412-1-1 through 412-1-M, and the amplifiers 414-. Amplified by 1-1 to 414-1-M. The amplified signals are then summed by the summators 416-1-1 through 416-1-M based on the antenna element, so that they are transmitted via one antenna array and then transmitted via the antennas.

4B illustrates an example in which an independent antenna array for each transmission path is used, and FIG. 4C illustrates an example in which transmission paths share one antenna array. However, according to another embodiment, some transmission paths may use an independent antenna array, and the other transmission paths may share one antenna array. Furthermore, according to another embodiment, by applying a switchable structure between transmission paths and antenna arrays, a structure that can be adaptively changed according to a situation may be used.

5 illustrates a situation in which a beam mismatch occurs in a wireless communication system according to various embodiments of the present disclosure.

Referring to FIG. 5, the base station 110 and the terminal 120 use an optimal beam as a serving beam through a beam search procedure. In this case, rotation or relocation of the terminal 120 may occur. In this case, if the direction of the beam set in the terminal 120 does not change, the absolute direction of the beam also changes as the terminal 120 rotates or moves. For this reason, the beam of the terminal 120 may not be directed toward the base station 110. That is, the beam of the terminal 120 is no longer the optimal beam, and this state is referred to as 'beam mismatch' in the present disclosure.

As described above, the beam mismatch refers to a state in which the beam determined through the previous beam training procedure is no longer the optimal beam due to the rotation and movement of the terminal 120 or the change in the channel environment. If a beam mismatch occurs, a large loss of link budget can occur until a new optimal beam is found through the next beam training procedure. As a result, a state in which data transmission and reception is impossible may occur. For example, if the beam width is 15 °, a link budget loss of about 2 to 3 dB is expected when beam mismatch occurs within 7 °, and a link budget loss of about 10 to 20 dB is expected when beam mismatch occurs above 7 °. do.

When the beam mismatch as shown in FIG. 5 occurs, if the serving beam is not changed properly, a decrease in communication quality occurs. However, deterioration in communication quality does not necessarily mean beam mismatch. For example, the serving beam is an optimal beam, but communication quality may be degraded due to interference, fading, and the like. In other words, if only the communication quality or the channel quality is dependent, there is a possibility of a determination error for the beam mismatch. Accordingly, the present disclosure describes various embodiments for more accurately detecting beam mismatches.

6 illustrates a method of operating a terminal in a wireless communication system according to various embodiments of the present disclosure. 6 illustrates an operation method for detecting a beam mismatch of the terminal 120.

Referring to FIG. 6, in step 601, a terminal receives reference signals beamformed into a plurality of transmit beams during a first period. Here, the first period is one of periods during which the base station repeatedly transmits reference signals for beam searching, and includes at least one time interval (eg, a subframe). That is, the base station sweeps reference signals periodically or on an event basis. In this case, the terminal performs reception beamforming using at least one reception beam. Accordingly, the terminal may obtain measurement values for each reception beam. Here, the measurement values may be referred to as 'RSRP (reference signal received power)' as a reception strength with respect to the reference signal. Using the measurement values, the terminal may determine the serving reception beam.

Then, in step 603, the terminal receives the reference signal beamformed into a plurality of transmission beams during the second period. Here, the second period is one of periods in which the base station repeatedly transmits reference signals for beam searching, and arrives after the first period and at least one time period pass. That is, during the communication, when the base station transmits the reference signals arrives, the terminal receives the reference signals transmitted from the base station. In this case, the terminal performs reception beamforming using at least one reception beam. Accordingly, the terminal may acquire two different sets of measured values obtained in the period in which the serving beam is determined and in the period thereafter.

In operation 605, the terminal determines whether there is a beam mismatch based on the measured values obtained during the first period and the measured values obtained during the second period. That is, the terminal may determine whether a beam mismatch has occurred by comparing measurement value sets for at least one reception beam and two or more transmission beams obtained at different points in time. Here, the measured measured values may or may not include measured values for the serving beam. At this time, if there is no similarity between the measurement value sets, the terminal determines the occurrence of the beam mismatch. Here, the rules for determining the existence of similarity may be variously defined. For example, the rule of similarity determination may be defined based on at least one of the measurement values themselves, the order of the measurement values, and statistics on the measurement values.

According to the embodiment described with reference to FIG. 6, a beam mismatch may be detected based on measurement value sets for the same beam pairs obtained at two different viewpoints. Since the base station repeatedly sweeps the reference signals for various purposes, the terminal may perform the measurement without additional overhead. In this case, measurement values for comparison may be obtained only by measuring at least one reception beam.

In the embodiment of FIG. 6, the serving reception beam is determined by the measurement values obtained from the reference signals received in step 601. However, according to another embodiment, in a situation where the serving beam is already determined, step 601 may be performed. In this case, the measured values compared in step 605 may be measured values measured at the time of determining the serving beam, or may be measured values measured from received reference signals (eg, reference signals received in step 601).

In the embodiment of FIG. 6, the measured measurement values include measurement values for at least one receive beam and a plurality of transmit beams. That is, beam mismatch detection may be performed using only one reception beam. However, according to another embodiment, measurement values for one base station transmit beam and multiple terminal receive beams may be used for mismatch detection. That is, mismatch detection according to another embodiment may be performed using only one transmission beam. The various embodiments described below are described on the premise that at least one receive beam and a plurality of transmit beams are used for convenience of description, but the embodiments can be easily applied even when a plurality of receive beams are used.

7A illustrates an operation method for beam mismatch detection based on a measurement pattern in a wireless communication system according to various embodiments of the present disclosure. 7A illustrates a method of operating the terminal 120.

Referring to FIG. 7A, in step 701, the terminal receives reference signals using an arbitrary reception beam. In other words, the terminal performs reception beamforming on reference signals using any reception beam. Within a specific beam full sweep period, the terminal receives the reference signals transmitted from the base station in any receive beam. In this case, the terminal receives all or part of the reference signals transmitted during the full sweep period.

In step 703, the terminal acquires pattern information of the measurement values. That is, the terminal measures the reception strength of the reference signals received in step 701 and stores the pattern of the measured values. Here, the pattern of measurement values may be defined as the relative magnitude relationship of the measurement values, that is, the ratio of the remaining measurement values to one measurement value. Alternatively, the pattern of measurement values may be defined as an order of transmission beams arranged in ascending or descending order of the measurement values. In this case, the measured values are determined for each reception beam. Hereinafter, the pattern of measurement values is referred to as a 'measurement pattern'.

In step 705, the terminal determines whether a previously obtained measurement pattern of the reception beam exists. In other words, the terminal determines whether another measurement pattern acquired before the measurement pattern obtained in step 703 is stored for the reception beam used in step 701. If the previously obtained measurement pattern does not exist, the terminal returns to step 701.

On the other hand, if there is a previously obtained measurement pattern, in step 707, the terminal compares two measurement patterns of the same reception beam. That is, the terminal compares the measurement pattern obtained in step 703 and the previously measured measurement pattern.

In step 709, the terminal determines whether the similarity between the measurement patterns is less than the threshold. Similarity may be variously defined according to a specific embodiment. For example, the similarity may be determined based on at least one of a difference between ratio values for the same transmission beam and an order of ratio values constituting each measurement pattern.

If the similarity is smaller than the threshold, in step 711, the terminal determines occurrence of beam mismatch. In other words, the terminal determines that the current serving beam is not the optimal beam. On the other hand, if the similarity is greater than or equal to the threshold, the terminal determines that no beam mismatch occurs, and returns to step 701.

A specific example of the embodiment described with reference to FIG. 7A is described below with reference to FIG. 7B. 7B illustrates an example of beam mismatch detection based on a measurement pattern in a wireless communication system according to various embodiments of the present disclosure.

Referring to FIG. 7B, during the nth full sweep period 710, the base station 110 repeatedly transmits beamformed reference signals. In this case, the terminal 120 receives reference signals using a plurality of receive beams. During the period 710, the terminal 120 acquires a plurality of measurement patterns including the measurement pattern 712 and the measurement pattern 714. Subsequently, during the n + 1 th full sweep period 720, the base station 110 repeatedly transmits beamformed reference signals. In this case, the terminal 120 acquires a measurement pattern 722 for at least one reception beam. In this case, since the measurement pattern 714 for the same reception beam as the measurement pattern 722 exists, the terminal 120 compares the measurement pattern 722 and the measurement pattern 714. In the example of FIG. 7B, the measurement pattern 714 and the measurement pattern 722 show different patterns. In this case, the terminal may determine that the similarity is smaller than the threshold, and may declare a beam mismatch.

According to the exemplary embodiment described with reference to FIGS. 7A and 7B, it is possible to detect channel degradation, that is, beam mismatch, not caused by interference or paging. In addition, since the measurement pattern is used without rescanning the optimal beam, it is possible to determine whether there is a beam mismatch in a very fast time.

In the embodiments of FIGS. 7A and 7B, the terminal declares a beam mismatch due to a change of a measurement pattern. However, according to another embodiment, for more accurate detection of the beam mismatch, the terminal may declare the beam mismatch only when the change of the measurement pattern is repeated a certain number of times. In this case, even when the number of transmission beams used by the base station is small, the accuracy of beam mismatch detection can be improved.

In addition, for more accurate detection of the beam mismatch, the terminal may determine the change of the measurement pattern in stages according to two or more criteria. Hereinafter, embodiments of determining the change of the measurement pattern will be described with reference to FIGS. 8A to 8E.

8A illustrates an operation method for beam mismatch detection based on an order of measurement values in a wireless communication system according to various embodiments of the present disclosure. 8A illustrates a method of operating the terminal 120.

Referring to FIG. 8A, in step 801, the terminal receives beamformed reference signals. In this case, the terminal performs reception beamforming using at least one reception beam. In this case, the terminal holds a set of measurement values for at least one reception beam prior to step 801. And, using the reference signals received in step 801, the terminal obtains another set of measurement values for the at least one reception beam. For convenience of description below, the present disclosure will be described based on measurement value sets for one receive beam.

Subsequently, in step 803, the terminal calculates a measured value change amount. That is, the terminal calculates a difference value between two sets of measured values. Here, the change amount may be defined in various ways. As an example, the amount of change may be the sum or average of the difference between the measured values for each transmission beam. In this case, at least one of the maximum value and the minimum value among the measured values may be excluded when calculating the sum or the average. For example, the amount of change may be determined as in Equation 1.

In Equation 1, ΔX _t is the difference between the t th measurement value and the t-1 th measurement value, X _t is the t th measurement value,

Is the mean of the difference between the measured values, and N is the number of measured values used to determine the mean.

In step 805, the terminal determines whether the amount of change is greater than a threshold. If the amount of change is greater than the threshold, it means that the measurement pattern is likely to change.

If the amount of change is less than or equal to the threshold, in step 807, the terminal initializes a counter for the change of the measurement pattern. The counter for changing the measurement pattern is a variable for counting how many measurement pattern changes have occurred. Thereafter, the terminal returns to step 801. Hereinafter, a counter for measuring pattern change is referred to as a 'measurement pattern change counter'.

On the other hand, if the amount of change is greater than the threshold, in step 809, the terminal compares the order of the measured values. Specifically, the terminal arranges the transmission beams in ascending or descending order according to the magnitude of the measurement values included in the two measurement value sets, and confirms that the order of the aligned transmission beams is identical. That is, the terminal checks whether the transmission beams having the largest measurement value are the same and the transmission beams having the second largest measurement value are the same in the two measurement value sets.

In operation 811, the terminal determines whether the order of the measured values has changed. If the order of the measurement values has not changed, that is, if the order of the measurement values is the same, the terminal initializes the measurement pattern change counter in step 807 and returns to step 801.

On the other hand, if the order of the measurement values has changed, in step 813, the terminal increments the measurement pattern change counter. That is, the terminal determines that a change in the measurement pattern has occurred, and records the number of changes.

In operation 815, the terminal determines that the measurement pattern change counter is greater than or equal to the threshold. That is, to declare a beam mismatch when a certain number of measurement pattern changes occur, the terminal compares the measurement pattern change counter with a threshold. However, when the threshold is set to 1, the beam mismatch may be declared only by one measurement pattern change. If the measurement pattern change counter is smaller than the threshold, the terminal initializes the measurement pattern change counter in step 807 and returns to step 801.

On the other hand, if the measurement pattern change counter is greater than or equal to the threshold, in step 817, the terminal determines the beam mismatch. That is, the terminal determines that a beam mismatch has occurred.

A specific example of the embodiment described with reference to FIG. 8A will now be described with reference to FIG. 8B. FIG. 8B illustrates a situation where a beam mismatch occurs, and FIG. 8C illustrates a situation where a beam mismatch occurs.

8B illustrates an example of beam mismatch detection based on the order of measurement values in a wireless communication system according to various embodiments of the present disclosure. Referring to FIG. 8B, during the nth full sweep period 810, the base station 110 repeatedly transmits beamformed reference signals. In this case, the terminal 120 receives reference signals using a plurality of receive beams. During the period 810, the terminal 120 acquires a measurement value set 812. Thereafter, during the n + 1 th full sweep period 820, the base station 110 transmits repeatedly beamformed reference signals. At this time, the terminal 120 obtains the measured value set 822. The measured value set 812 and the measured value set 822 differ in the amount of change. The order of the measured values in the measured value set 812 is '2-3-1-5-6-4', and the order of the measured values in the measured value set 822 is '5-6-4-2-3-1' As such, the orders are different. Therefore, since the amount of change is larger than the threshold and the order is different, an inconsistency is declared.

8C illustrates another example of beam mismatch detection based on the order of measurement values in a wireless communication system according to various embodiments of the present disclosure. Referring to FIG. 8C, during the nth full sweep period 810, the base station 110 repeatedly transmits beamformed reference signals. In this case, the terminal 120 receives reference signals using a plurality of receive beams. During the period 810, the terminal 120 acquires a set of measurement values 814. Thereafter, during the n + 1 th full sweep period 820, the base station 110 transmits repeatedly beamformed reference signals. At this time, the terminal 120 obtains the measured value set 824. The measured value set 814 and the measured value set 824 differ in the amount of change. However, the order of the measured values in the measured value set 814 is '2-1-3-5-6-4' and the order of the measured values in the measured value set 824 is '2-1-3-5-6-4' As such, the orders are the same. Thus, although the amount of change is greater than the threshold, i.e., the offsets are different, due to the same order, no beam mismatch is declared.

According to the embodiment described with reference to FIGS. 8A to 8C, a beam mismatch, which is not a cause of interference or paging, may be detected. Furthermore, implementation and determination accuracy may be secured through two-step determination in consideration of the change amount and order of the measurement values. Moreover, due to the introduction of the pattern change counter, accuracy can be ensured even when the transmission beam of the base station is small.

In this case, in order to prevent an incorrect determination of the beam mismatch, it is necessary to consider the measurement error in determining the order of the measurement values. Although the movement or rotation of the terminal does not occur, if the difference in the measured value between the transmission beams is small, the order may be reversed by a small measurement error or randomness (randomness). Accordingly, in order to prevent false beam mismatch declaration due to measurement error or the like, an embodiment in which grouping of measurement values is introduced is described below with reference to FIGS. 8D and 8E.

8D illustrates a method of operation for grouping measured values in a wireless communication system according to various embodiments of the present disclosure. 8D illustrates an operation method of the terminal 120.

Referring to FIG. 8D, in step 851, the terminal receives beamformed reference signals. In this case, the terminal performs reception beamforming using at least one reception beam. Using the received reference signals, the terminal obtains another set of measurement values for at least one receive beam. For convenience of description below, the present disclosure will be described based on measurement value sets for one receive beam.

In operation 853, the terminal arranges the transmission beams based on the measured value. That is, the terminal identifies a transmission beam corresponding to the largest measured value, a transmission beam corresponding to the second largest measured value, and the like. Accordingly, the transmission beams are arranged in the order of magnitude of the measured values.

Then, in step 855, the terminal checks whether the difference between the measured values is less than the threshold. That is, the terminal determines whether the difference between the measurement values is smaller than the threshold value for each of the beam beam pairs having the adjacent order among the aligned transmission beams. Here, the threshold may be adjusted based on a measurement error or randomness with respect to the reference signal.

If the difference between the measured values is smaller than the threshold, in step 857, the UE sets the same rank by grouping the corresponding transmission beam pairs. At this time, three or more transmission beams may be set to the same rank according to a difference from the measured value of the next transmission beam.

If the difference between the measured values is greater than or equal to the threshold, in step 859, the terminal sets a lower order of priority. That is, the terminal sets two transmission beams in the corresponding transmission beam pair to different ranks.

A specific example of the beam mismatch determination applying the embodiment described with reference to FIG. 8D will now be described with reference to FIG. 8E. 8E illustrates an example of beam mismatch detection based on an order of a group of measurement values in a wireless communication system according to various embodiments of the present disclosure.

Referring to FIG. 8D, during the nth full sweep period 810, the base station 110 repeatedly transmits beamformed reference signals. In this case, the terminal 120 receives reference signals using a plurality of receive beams. During the period 810, the terminal 120 acquires the measurement value set 816. Thereafter, during the n + 1 th full sweep period 820, the base station 110 transmits repeatedly beamformed reference signals. At this time, the terminal 120 obtains the measured value set 826. The measured value set 816 and the measured value set 826 show a difference in the amount of change. The order of the measured values in the measured value set 816 is '2-1-3-5-6-4', and the order of the measured values in the measured value set 826 is '2-3-1-5-6-4' As such, the orders are different. However, since the difference between the measured values of the transmission beam # 1 and the transmission beam # 3 is smaller than the threshold value, the transmission beam # 1 and the transmission beam # 3 are grouped to have the same rank. In this case, the order difference between '1-3' and '3-1' does not affect the determination of the measurement pattern change. Thus, no beam mismatch is declared. This can prevent erroneous determination of beam mismatch due to the reversed order due to measurement error or randomness.

9 illustrates a state transition diagram related to beam mismatch in a wireless communication system according to various embodiments of the present disclosure. 9 illustrates a state transition diagram of a beam mismatch determination procedure incorporating a two-step measurement pattern change in consideration of the amount of change and the order of change.

Referring to FIG. 9, initially, the state is in beam aligned state 910. If the amount of change in the measurement values exceeds the threshold, the state transitions to a measurement value changed state 920. In the measurement value change state 920, if the sequence change is determined, the state transitions to the measurement pattern changed state 930. At this time, even if the measurement pattern change occurs in consecutive periods below the threshold number, the measurement pattern change state 930 is maintained. Within successive periods below the threshold number, if no order change is determined, the state transitions to measurement value change 920. Also, within successive periods below the threshold number, if the amount of change is below the threshold or if out of order is determined, the state transitions to beam alignment state 910. If the measurement pattern change occurs in successive periods above the threshold number in the measurement pattern change state 930, the state transitions to a beam misaligned state 940. In the beam mismatch state 940, if the beam mismatch is recovered, the state returns to the beam alignment state 910.

According to the various embodiments described above, the beam mismatch can be detected. The determination result of the beam mismatch can be used in various ways. According to an embodiment, the determination of the beam mismatch may be utilized for power control of the receiver of the terminal 120. In detail, the determination of the beam mismatch may be used for power control when operating in a discontinuous reception (DRX) mode. In this case, the DRX mode may turn off and sleep hardware of a physical layer while maintaining a connected state, that is, an active state, in a higher layer (eg, a radio resoure control (RRC) layer). It is an operation mode which temporarily deactivates all or part of the receiving circuit by controlling in a manner such as (sleep).

When operating in the DRX mode, the on duration and the sleep duration are repeated according to a DRX cycle or a DRX period. In this case, the terminal 120 receives a signal transmitted from the base station 110 by activating the receiving circuit in the on period, and deactivates the receiving circuit in the sleep period. Here, activation may be referred to as wake up and inactivation may be referred to as sleep. In the case of a system performing communication on the premise of beamforming, within a DRX period, the terminal 120 transmits feedback on a preferred beam to the base station 110 at least once. In addition, in the on period, the base station 110 may transmit downlink scheduling information.

At this time, even if activated in the on period, if the beam is not aligned, the terminal cannot receive a signal. Therefore, before the on period is sufficient (eg, time required for beam searching), the terminal should activate the receiving circuit and then perform beam searching. However, the beam used in the previous on interval is not necessarily invalid. Accordingly, the terminal that activates the receiving circuit before a sufficient time for the on period to arrive, may control the subsequent operation state according to the determination of whether there is a beam mismatch. Accordingly, the present disclosure will be described with reference to FIGS. 10A, 10B, and 10C according to an embodiment of control of a reception circuit according to a result of beam mismatch detection while operating in the DRX mode.

10A illustrates an operation method for power control based on beam mismatch detection in a wireless communication system according to various embodiments of the present disclosure. 10A illustrates an operation method of the terminal 120.

Referring to FIG. 10A, in step 1001, the terminal enters a discontinuous operation mode (eg, a DRX mode). The DRX mode is entered under the control of the base station. That is, the terminal receives a message instructing to enter the DRX mode from the base station. Accordingly, the terminal operates the on period and the sleep period according to the DRX cycle. During the sleep period, the terminal may deactivate all or part of the receiving circuit.

In step 1003, the UE determines whether there is a beam mismatch during the sleep period. According to an embodiment, the terminal may perform beam measurement. That is, the terminal temporarily activates the receiving circuit during the sleep period and receives beamformed reference signals transmitted from the base station. That is, the terminal determines whether the beam mismatch occurs by comparing the newly measured values with the measured values obtained before entering the previous on interval or the DRX mode. For example, the terminal may determine whether there is a beam mismatch according to one of the various embodiments described above. According to another embodiment, the terminal may determine whether there is a beam mismatch using a sensor provided in the terminal. In order to determine whether there is a beam mismatch using the sensor, the terminal checks whether the terminal has rotated or moved after the previous beam search. In this case, the timing of determining whether there is a beam mismatch is a predetermined time from the on interval, and the predetermined time is greater than or equal to a time required for performing beam recovery, that is, a time required for beam realignment.

Subsequently, in step 1005, the terminal checks whether a beam mismatch occurs. If it is determined that a beam mismatch occurs, in step 1007, the terminal performs a beam recovery procedure. The beam recovery procedure may be performed in various ways according to a specific embodiment. For example, as a beam recovery procedure, the terminal may perform a beam search procedure. Alternatively, the terminal may perform a beam recovery procedure according to various embodiments described below.

On the other hand, if it is determined that no beam mismatch occurs, in step 1009, the terminal maintains a sleep state until the on-interval arrives. Here, before the arrival of the on period means a time point considering the time required for normalization of the receiving circuit. That is, since the beams are aligned without mismatching of the beams, no additional beam recovery procedure is required. Therefore, the terminal can reduce power consumption by keeping the receiving circuit in an inactive state for the remaining sleep period.

A detailed example of the embodiment described with reference to FIG. 10A is described below with reference to FIG. 7B. 10B and 10C illustrate examples of power control based on beam mismatch detection in a wireless communication system according to various embodiments of the present disclosure.

10B illustrates a case of determining whether there is a beam mismatch based on beam measurement. Referring to FIG. 10B, when the on period ends, the terminal 120 enters a sleep period and deactivates the receiving circuit. At this time, the terminal temporarily activates the receiving circuit and detects the beam mismatch before time 1002 by Δt from the next on period. Depending on the detection result of the beam mismatch, the operating state of the receiving circuit for a period of time 1002 may vary.

10C illustrates a case of determining whether a beam mismatches based on a sensor value. Referring to FIG. 10C, when the on period ends, the terminal 120 enters a sleep period and deactivates the receiving circuit. At this time, the terminal detects the beam mismatch by using the sensor value before time 1002 by Δt from the next on interval. Depending on the detection result of the beam mismatch, the operating state of the receiving circuit for a period of time 1002 may vary. In the case of using the sensor as shown in FIG. 10C, since the temporary activation of the receiving circuit is not required, the sleep state can be kept longer.

10B and 10C, when beam mismatch occurs, the terminal 120 performs a beam recovery procedure. As described below, the beam recovery procedure may include measurements for the beams. However, in some embodiments, the beam may be recovered based on past beam measurement results or sensor values, without measuring the beams. When the beam is recoverable without the beam measurement, the terminal 120 detecting the beam mismatch may maintain the sleep state after recovering the beam. According to another embodiment, when a beam recovery procedure based on beam measurement is performed, if beam recovery is completed before the on-interval arrives, the terminal 120 may maintain a sleep state for the remaining sleep period.

According to the exemplary embodiment described with reference to FIGS. 10A and 10B, a sleep period capable of inactivating the receiving circuit during the DRX mode may be used more effectively. That is, according to the quick beam mismatch determination, the terminal may secure a longer sleep period. In this case, when it is determined that the beam mismatch occurs, the terminal performs a beam recovery procedure for the remaining period of the sleep period. Hereinafter, the present disclosure describes various embodiments for beam recovery.

The base station 110 according to various embodiments sweeps reference signals on a periodic or event basis for beam searching of the terminal 120. In this case, the base station 110 may support at least two reference signal transmission schemes. For example, reference signal transmission schemes are the same as those of FIGS. 11A and 11B. 11A and 11B illustrate transmission schemes of reference signals supported in a wireless communication system according to various embodiments of the present disclosure.

11A illustrates a reference signal transmission scheme for beam searching of a plurality of terminals including the terminal 120. Referring to FIG. 11A, the base station 110 sweeps all transmission beams of the base station 110, and the sweep of all transmission beams is repeatedly performed. In this case, the reference signal may be referred to as 'beam reference signal (BRS)'. Accordingly, the terminal 120 may receive the reference signals using different reception beams for each sweep, thereby performing measurement on all combinations of the transmission beam and the reception beam. Reference signal transmission in the same manner as in FIG. 11A may be performed periodically.

11b illustrates a reference signal transmission scheme for beam searching of a specific terminal (eg, terminal 120). Referring to FIG. 11B, the base station 110 transmits reference signals for the terminal 120 during a specific time period (eg, a subframe). In this case, the reference signal may be referred to as a beam refinement reference signal (BRRS). The downlink period in the time interval is allocated for the reference signal (eg, BRRS) in addition to the control channel (eg, a physical downlink control channel (PDCCH)). Here, the reference signal may be repeated many times (for example, four times) within one symbol. At this time, the base station 110 may sweep all the transmission beams, or only some of the transmission beams. Reference signal transmission in the same manner as in FIG. 11B may be performed by a request of the terminal 120.

As described with reference to FIGS. 11A and 11B, two or more reference signal transmission schemes may be supported. 11A may be performed for a plurality of terminals, but the time required is long. On the other hand, the method as shown in FIG. 11B may be performed within a short time, but data may not be transmitted during the corresponding time period. Therefore, using the detection of the beam mismatch, the two reference signal transmission techniques described above may be operated as shown in FIG. 11C.

11C illustrates signal exchange for a beam recovery procedure using intensive reference signal transmission in a wireless communication system according to various embodiments of the present disclosure. 11C illustrates a signal exchange between the base station 110 and the terminal 120.

Referring to FIG. 11C, in steps 1101-1 to 1101-N, the base station 110 transmits reference signals. Reference signals are swept N times and transmitted on at least one subframe. In this case, the terminal 120 performs reception beamforming using at least one reception beam for each sweep. Accordingly, the terminal 120 may select the optimal beam as the serving beam. Here, the serving beam includes a serving transmission beam of the base station 110 and a serving receiving beam of the terminal 120.

In step 1103, the terminal 120 transmits beam feedback indicating the serving beam to the base station 110. Here, the beam feedback may indicate the serving transmission beam of the base station 110. The beam feedback includes identification information of the serving transmission beam, and the identification information may be referred to as a 'beam selection index (BSI)'.

In step 1105, the terminal 120 detects a beam mismatch. The terminal 120 performs measurement on at least one reception beam, compares the measured values with previously obtained measured values, and detects a beam mismatch based on a comparison result. For example, the terminal 120 may detect a beam mismatch according to one of the various embodiments described above. Accordingly, the beam recovery procedure proceeds as follows.

In step 1107, the terminal 120 transmits a BRRS request to the base station 110. In other words, when it is determined that the beam mismatch occurs, the terminal 120 transmits a message requesting transmission of reference signals specific to the terminal 120 to the base station 110. That is, the terminal 120 triggers a beam recovery procedure. Accordingly, in step 1109, the base station 110 transmits BRRS allocation information. Subsequently, in step 1111, the base station 110 repeatedly transmits reference signals, that is, BRRSs. Accordingly, the terminal 120 may determine the optimal beam again. Thereafter, in step 1113, the terminal 120 transmits a BRRS feedback for notifying the serving beam to the base station 110.

According to the exemplary embodiment described with reference to FIGS. 11A through 11C, the beam mismatch situation may be eliminated. Specifically, in the case of beam mismatch, beam recovery may be performed by the terminal-specific intensive reference signal transmission. That is, detection of beam mismatch can be used as a condition of intensive reference signal transmission such as BRRS.

Although the reference signal transmission scheme such as FIG. 11B requires a shorter time than the scheme of FIG. 11A, the time for transmitting repetitive reference signals for measurement is still required. Thus, the procedure for recovering the beam in a shorter time is described below with reference to FIGS. 12A-12C.

12A illustrates an operation method for recovering a beam using previous measurement results in a wireless communication system according to various embodiments of the present disclosure. 12A illustrates a method of operating the terminal 120.

12A, in step 1201, the UE detects a beam mismatch. The terminal may perform measurement on at least one receiving beam, compare the measured values with previously obtained measured values, and then detect the beam mismatch based on the comparison result. For example, the terminal may detect a beam mismatch according to one of the various embodiments described above.

Subsequently, in step 1203, the terminal identifies a previous measurement pattern similar to the current measurement pattern. That is, the terminal checks the past measurement pattern that is similar to the measurement pattern obtained when determining the beam mismatch in step 1201, that is, the beam mismatch will not be declared when compared with the current measurement pattern. That is, the terminal stores information about past measurement patterns and can search for it.

Then, in step 1205, the terminal uses the serving beam at the time of acquiring the confirmed previous measurement pattern. If the measurement patterns are similar, it can be expected that the optimal beam will be the same. Accordingly, the terminal sets the serving beam at the time when the measurement pattern similar to the current measurement pattern is present as the current serving beam. Here, the serving beam when acquiring the previous measurement pattern may be a beam selected based on a measurement result corresponding to the previous measurement pattern, or may be a beam selected through beam recovery after the beam mismatch is determined by the previous measurement pattern. In this case, according to another embodiment, the terminal may determine whether the use of the previous serving beam is still valid. For example, the terminal may determine the validity based on the time elapsed from the acquisition time of the previous measurement pattern.

According to the embodiment described with reference to FIG. 12A, the beam may be recovered without additional beam searching. However, there may be cases where there is no previous measurement pattern similar to the current measurement pattern. Therefore, according to another embodiment, as shown in FIG. 12B, additional beam search may be considered together.

12B illustrates an operation method for recovering a beam using a previous measurement or using a new measurement in a wireless communication system according to various embodiments of the present disclosure. 12B illustrates an operation method of the terminal 120.

12B, in step 1251, the UE detects a beam mismatch. The terminal may perform measurement on at least one receiving beam, compare the measured values with previously obtained measured values, and then detect the beam mismatch based on the comparison result. For example, the terminal may detect a beam mismatch according to one of the various embodiments described above.

In step 1253, the terminal checks whether a previous measurement pattern similar to the current measurement pattern exists. That is, the terminal checks the past measurement pattern similar to the measurement pattern obtained when determining the beam mismatch, that is, the beam mismatch will not be declared when compared with the current measurement pattern. That is, the terminal stores information about past measurement patterns and corresponding beams, and may search for them using the measurement pattern.

If there is a previous measurement pattern similar to the current measurement pattern, in step 1255, the terminal sets the beam corresponding to the previous measurement pattern as the serving beam. If the measurement patterns are similar, it can be expected that the optimal beam will be the same. Accordingly, without additional beam searching, the terminal reuses the serving beam at the time when the measurement pattern similar to the current measurement pattern was shown. In other words, the terminal sets the serving beam determined when acquiring the previous measurement pattern as the current serving beam.

If there is no previous measurement pattern similar to the current measurement pattern, in step 1257, the terminal performs a beam recovery procedure based on the beam search. To this end, the terminal may request transmission of reference signals to the base station. For example, the UE may perform a beam recovery procedure according to the embodiment described with reference to FIG. 11C.

In step 1259, the terminal stores measurement pattern information and beam information. That is, the terminal stores the measurement result obtained in step 1257. The stored measurement results can then be used for detection of beam mismatch. The stored measurement results can also be used for beam recovery in the event of beam mismatch later.

In step 1261, the terminal establishes a valid time window. Selecting the serving beam by the similarity of the measurement pattern is possible on the premise of the similarity of the position of the terminal. Therefore, if the relative position with respect to the base station is changed as the terminal moves, even a beam corresponding to the same or similar measurement pattern may not be an optimal beam. Therefore, the validity of past measurement records is limited and the validity period is managed through the valid time window. In this case, the valid time window may be defined as a fixed value or dynamically adjusted based on an environment (eg, a moving speed) of the terminal.

Subsequently, in step 1263, the terminal sets the beam determined through the beam recovery procedure as the serving beam. That is, the terminal sets the optimal beam selected in step 1257 as the serving beam. In addition, the terminal may transmit feedback information indicating the serving transmission beam of the base station.

In step 1265, the terminal communicates using the serving beam. Specifically, the terminal receives the data signal transmitted from the base station using the serving reception beam. Here, the reception of the data signal includes decoding and decoding.

In step 1267, the terminal determines whether the beam mismatch is recovered. In other words, the terminal determines whether the serving beam set in step 1255 or step 1261 is an optimal beam, that is, provides sufficient channel quality to perform communication. Recovery of beam mismatch can be determined in various ways. For example, the terminal may determine whether the beam mismatch is recovered based on whether the decoding of the received data signal is successful. If the beam mismatch is recovered, the terminal returns to step 1251.

On the other hand, if the beam mismatch is not recovered, in step 1269, the terminal deletes the corresponding measurement pattern information and beam information. That is, even though the serving beam set in step 1255 or step 1261 is not set, the beam mismatch is not recovered, which means that the measurement result is unreliable. Therefore, since the measurement result cannot be used for later beam mismatch determination or recovery, the terminal discards the measurement result.

A detailed example of the embodiment described with reference to FIG. 12A or 12B will now be described with reference to FIG. 12C. 12C illustrates an example of beam recovery using previous measurement results in a wireless communication system according to various embodiments of the present disclosure.

Referring to FIG. 12C, during the nth full sweep period 1210, the base station 110 repeatedly transmits beamformed reference signals. In this case, the terminal 120 receives reference signals using a plurality of receive beams. During the period 1210, the terminal 120 obtains a plurality of measurement results including the measurement result 1212 corresponding to the reception beam 1262. At this time, the beam mismatch is determined, and through the beam recovery procedure, the terminal 120 selects the beam # k as the serving beam.

Thereafter, during the n + x th full sweep period 1220, the base station 110 transmits repeatedly beamformed reference signals. In this case, the terminal 120 acquires the measurement pattern 1222 for at least one reception beam. In addition, the terminal 120 determines occurrence of a beam mismatch and confirms a previous measurement pattern similar to the measurement pattern 1222. In the case of FIG. 12C, the measurement pattern 1212 acquired in the period 1210 is similar to the measurement pattern 1222. Accordingly, the terminal 120 sets the beam #k, which has been selected through the recovery procedure by the beam mismatch declaration in the period 1210, as the serving beam without the beam search.

According to the exemplary embodiment described with reference to FIGS. 12A to 12C, by using previous measurement results, beam recovery may be performed without a beam searching procedure. In addition, the present disclosure will be described below with reference to FIGS. 13A to 13D to describe another embodiment of recovering a beam without beam searching.

13A illustrates an operation method for recovering a beam using sensor values in a wireless communication system according to various embodiments of the present disclosure. 13A illustrates an operation method of the terminal 120.

Referring to FIG. 13A, in step 1301, the UE detects beam mismatch detection. The terminal may perform measurement on at least one receiving beam, compare the measured values with previously obtained measured values, and then detect the beam mismatch based on the comparison result. For example, the terminal may detect a beam mismatch according to one of the various embodiments described above.

In step 1303, the terminal determines a movement amount using a sensor value. Here, the sensor value is a value representing a physical change obtained by at least one sensor capable of measuring rotation and displacement of the terminal. For example, at least one of a gyro sensor, an acceleration sensor, a compass sensor, a gravity sensor, and a G-sensor may be used to determine the degree of movement.

In step 1305, the terminal determines a new serving beam based on the degree of movement. The terminal determines the rotation / movement of the antenna based on the degree of movement, that is, how much the terminal rotates and how much the terminal moves, and selects a new serving beam capable of compensating the amount of rotation / movement of the antenna. For example, referring to FIG. 13B, the coordinates 1302 (X1, Y1, Z1) in the main gain direction of the current serving beam reflect the degree of movement (dX, dY, dZ) measured by the sensor. Accordingly, the terminal may determine coordinates 1304 (X2, Y2, Z2) = (X1 + dx, Y1 + dy, Z1 + dz) of the new main gain direction. The terminal may select a beam having a direction most similar to the new main gain direction as the serving beam.

In the embodiment of FIG. 13A, beam mismatch detection in step 1301 is performed using measured values for reference signals according to the various embodiments described above. However, according to another embodiment, detection of the beam mismatch may also be performed based on the sensor value. In detail, when a movement degree exceeding a threshold is measured through a sensor value, the terminal may declare a beam mismatch. According to another embodiment, for more accurate beam mismatch detection, the beam mismatch may be detected based on the sensor value as well as the measured value for the reference signals. In this case, even when the activity level of the sensor is not accurately measured, if the change of the measurement pattern is used together, the beam mismatch can be detected more accurately.

According to the embodiment described with reference to FIG. 13A, by using a sensor value, beam recovery is possible without a beam searching procedure. When beam mismatch detection or night recovery is performed using the sensor value as shown in FIG. 13A, the installation position of the sensor may affect accuracy. For example, when the sensor and the antenna are separated by a predetermined distance or more, the degree of movement obtained through the sensor value may be different from that of the antenna. In order to overcome the difference in the degree of movement according to the installation position of the sensor, the structure as shown in Figure 13c or 13d may be applied. 13C and 13D illustrate examples of installation of a sensor in a wireless communication system according to various embodiments of the present disclosure.

Referring to FIG. 13C, the terminal includes an AP 1310, a baseband (BB) circuit 1320, an RFIC 1330, and an antenna 1340, and a sensor 1350 is installed in the RFIC 1330. Due to the millimeter wave characteristics, the path loss is large, so that the RFIC 1330 may be disposed to approach the antenna 1340. Therefore, when the sensor 1350 is installed in the RFIC 1330, the sensor 1350 is physically installed close to the antenna 1340. In this case, the degree of movement determined based on the measured values measured by the sensor 1350 may be treated as the degree of movement of the antenna 1340. In this case, the sensor 1350 may be an additional component for measuring the movement of the antenna 1340, which is separate from the sensor used for other purposes.

Referring to FIG. 13D, the terminal includes an AP 1310, a BB circuit 1320, an RFIC 1330, and an antenna 1340, and includes a sensor 1350 and a sensor hub 1360. Unlike the embodiment of FIG. 13C, the structure of FIG. 13D does not specify the position of the sensor 1350. However, the AP 1310 or another processor performs calibration on the degree of movement by using information on the installation position of the sensor 1350 and the installation position of the antenna 1340, and sets a compensation value. Therefore, the terminal may compensate for the sensor value measured by the sensor 1350 or the new direction coordinate determined from the sensor value based on the compensation value, and then use the value for the antenna.

Methods according to the embodiments described in the claims or the specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

When implemented in software, a computer-readable storage medium for storing one or more programs (software modules) may be provided. One or more programs stored in a computer readable storage medium are configured for execution by one or more processors in an electronic device. One or more programs include instructions that cause an electronic device to execute methods in accordance with embodiments described in the claims or specifications of this disclosure.

Such programs (software modules, software) may include random access memory, non-volatile memory including flash memory, read only memory (ROM), and electrically erasable programmable ROM. (electrically erasable programmable read only memory (EEPROM), magnetic disc storage device, compact disc-ROM (CD-ROM), digital versatile discs (DVDs) or other forms It can be stored in an optical storage device, a magnetic cassette. Or, it may be stored in a memory composed of some or all of these combinations. In addition, each configuration memory may be included in plural.

In addition, the program may be configured through a communication network composed of a communication network such as the Internet, an intranet, a local area network (LAN), a wide area network (WAN), or a storage area network (SAN), or a combination thereof. It may be stored in an attachable storage device that is accessible. Such a storage device may be connected to a device that performs an embodiment of the present disclosure through an external port. In addition, a separate storage device on a communication network may be connected to a device that performs an embodiment of the present disclosure.

In the above-described specific embodiments of the present disclosure, the components included in the disclosure are expressed in the singular or plural according to the specific embodiments presented. However, the singular or plural expressions are selected to suit the circumstances presented for convenience of description, and the present disclosure is not limited to the singular or plural elements, and the singular or plural elements may be used in the singular or the singular. Even expressed components may be composed of a plurality.

Meanwhile, in the detailed description of the present disclosure, specific embodiments have been described. However, various modifications may be possible without departing from the scope of the present disclosure. Therefore, the scope of the present disclosure should not be limited to the described embodiments, but should be determined not only by the scope of the following claims, but also by the equivalents of the claims.

Claims

In the method of operation of a terminal in a wireless communication system,

Receiving a plurality of reference signals during a first period of time;

Receiving a plurality of reference signals during a second period of time,

Determining whether there is a beam mismatch based on a first set of measurement values for the plurality of reference signals received during the first period and a second set of measurement values for the plurality of reference signals received during the second period. How to.
The method according to claim 1,

Wherein the first set of measurement values and the second set of measurement values comprise two or more measurement values for at least one same beam.
The method according to claim 1,

The process of determining whether the beam mismatch,

Comparing a first pattern of measured values included in the first set of measured values and a second pattern of measured values included in the second set of measured values;

If the similarity between the first pattern and the second pattern is less than a threshold, declaring the beam mismatch;

Wherein the first pattern and the second pattern are defined based on at least one of a relative magnitude relationship of the measured values, an order of beams arranged in ascending or descending order of the measured values.
The method according to claim 1,

The process of determining whether the beam mismatch,

When the amount of change in the measured values between the first set of measured values and the second set of measured values exceeds a first threshold, comparing the order of the beams according to the measured values of the first set of measured values and the second set of measured values. Process,

If the order has changed consecutively more than a second threshold, declaring the beam mismatch.
The method according to claim 4,

The order of the beams is determined such that the beams corresponding to the measured values having a difference below the third threshold have the same rank.
The method according to claim 1,

The occurrence of the beam mismatch is determined in a sleep duration during operation in a discontinuous operation mode in which the receiving circuit is periodically inactivated.

And determining that the beam mismatch does not occur, deactivating the receiving circuit until an on-interval arrives.
The method according to claim 1,

As the beam mismatch occurs, transmitting a message requesting transmission of reference signals specific to the terminal to a base station;

Determining a new serving beam using the reference signals.
The method according to claim 1,

Ascertaining that the beam mismatch occurs, identifying previous measurement values having a pattern similar to the pattern of the measurement values of the second set of measurement values;

Determining the serving beam determined upon obtaining the previous measurement values as a new serving beam.
The method according to claim 1,

Determining that the new serving beam is based on the direction coordinate of the main gain of the current serving beam and the amount of rotation or movement measured by the at least one sensor as it is determined that the beam mismatch occurs.
In the method of operation of a terminal in a wireless communication system,

Activating a receiving circuit to receive a signal during an on duration of the discontinuous mode of operation;

Deactivating the receiving circuit when a sleep period arrives;

Determining whether a beam mismatch occurs after a first partial elapse of the sleep period;

If the beam mismatch occurs, activating the receiving circuit to recover the beam during the second portion of the sleep period.
The method according to claim 10,

If the beam mismatch does not occur, further comprising deactivating the receiving circuit during the second portion.
The method according to claim 10,

The second portion has a length greater than the time required to perform a procedure for recovering the beam.
An apparatus of a terminal of a wireless communication system, wherein the apparatus is configured to perform the method of claims 1 to 9.
An apparatus of a terminal of a wireless communication system, wherein the apparatus is configured to perform the method of claims 10-12.