Apparatus and method for detecting beam misalignment in a wireless communication system

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 includes the steps of: receiving a plurality of reference signals in a first period; receiving a plurality of reference signals in a second period; and determining whether the beam is misaligned based on a first measurement value group of the plurality of reference signals received in the first period and a second measurement value group of the plurality of reference signals received in the second period. This research was supported by the Ministry of Science, ICT and Future Planning under the "Government Level Giga KOREA Business" project.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to a wireless communication system, and more particularly, to an apparatus and method for detecting beam misalignment in a wireless communication system.

[0002] This research was supported by the Ministry of Science, ICT and Future Planning under the "Government Level Giga KOREA Business" project. BACKGROUND

[0003] To meet increasing demand for wireless data traffic since the deployment of fourth generation (4G) communication systems, efforts have been made to develop improved fifth generation (5G) or pre-5G communication systems. Therefore, 5G or pre-5G communication systems are also called "beyond 4G networks" or "post long term evolution (LTE) systems."

[0004] 5G communication systems are considered to be implemented in higher frequency (millimeter wave) bands, such as 60 GHz bands, so as to accomplish higher data rates. To decrease propagation loss of the radio waves and increase the transmission distance, the beamforming, massive multiple-input multiple-output (MIMO), full dimensional MIMO (FD-MIMO), array antenna, an analog beam forming, large scale antenna techniques are discussed in 5G communication systems.

[0005] In addition, the development for system network improvement is in progress based on advanced small cells, cloud radio access networks (RANs), ultra-dense networks, a device to device (D2D) communication, a wireless backhaul, a moving network, a cooperative communication, coordinated multi-points (CoMP), a reception-end interference cancellation and the like.

[0006] In the 5G system, hybrid frequency shift keying (FSK) and quadrature amplitude modulation (FQAM) and sliding window superposition coding (SWSC) as an advanced coding modulation (ACM), and filter bank multi carrier (FBMC), a non-orthogonal multiple access (NOMA), and a sparse code multiple access (SCMA) as an advanced access technology have been developed. SUMMARY

[0007] TECHNICAL PROBLEM

[0008] Based on the above discussion, the present disclosure provides an apparatus and method for efficiently performing beamforming in a wireless communication system.

[0009] In addition, the present disclosure provides an apparatus and method for using an optimal beam in a wireless communication system.

[0010] In addition, the present disclosure provides an apparatus and method for detecting beam misalignment in a wireless communication system.

[0011] Further, the disclosure provides an apparatus and a method for resolving a beam misalignment situation in a wireless communication system.

[0012] Further, the disclosure provides an apparatus and a method for triggering dense reference signal transmission for beam search in a wireless communication system.

[0013] Further, the disclosure provides an apparatus and a method for determining a serving beam based on a measurement pattern of a transmission beam in a wireless communication system.

[0014] Further, the disclosure provides an apparatus and a method for determining a serving beam based on a measurement value of a sensor in a wireless communication system.

[0015] Solution to the problem

[0016] According to various embodiments of the disclosure, a method for operating a terminal in a wireless communication system includes receiving a plurality of reference signals in a first period, receiving a plurality of reference signals in a second period, and determining whether a beam is misaligned based on a first set of measurement values of the plurality of reference signals received in the first period and a second set of measurement values of the plurality of reference signals received in the second period.

[0017] According to various embodiments of the disclosure, a method for operating a terminal in a wireless communication system includes, in an on duration of a discontinuous operation mode, activating a reception circuit to receive a signal, if a sleep duration arrives, deactivating the reception circuit after a first portion of the sleep duration elapses, determining whether a beam is misaligned, and if a beam misalignment occurs, activating the reception circuit to recover a beam in a second portion of the sleep duration.

[0018] According to various embodiments of the disclosure, an apparatus for a terminal in a wireless communication system includes a reception unit to receive a plurality of reference signals in a first period and to receive a plurality of reference signals in a second period, and a controller to determine whether a beam is misaligned based on a first set of measurement values of the plurality of reference signals received in the first period and a second set of measurement values of the plurality of reference signals received in the second period.

[0019] According to various embodiments of the disclosure, an apparatus for a terminal in a wireless communication system includes a reception circuit selectively activated in a discontinuous operation mode, and a controller to control the reception circuit. Here, the controller activates the reception circuit to receive a signal in an on duration of the discontinuous operation mode, if a sleep duration arrives, deactivates the reception circuit after a first portion of the sleep duration elapses, determines whether a beam is misaligned, and if a beam misalignment occurs, activates the reception circuit to recover a beam in a second portion of the sleep duration.

[0020] Advantages of the Invention

[0021] The apparatuses and methods according to various embodiments of the disclosure can detect beam misalignment by using measurement results of a plurality of beams, and thus can more accurately determine beam misalignment.

[0022] Effects obtainable from the present disclosure are non-limited the above-mentioned effects, and other unmentioned effects can become apparent to those skilled in the art from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 A wireless communication system according to various embodiments of the disclosure is illustrated.

[0024] Figure 2 A configuration of a base station in a wireless communication system according to various embodiments of the disclosure is illustrated.

[0025] Figure 3 A configuration of a terminal in a wireless communication system according to various embodiments of the disclosure is illustrated.

[0026] Figures 4a to 4c A configuration of a communication unit in a wireless communication system according to various embodiments of the disclosure is illustrated.

[0027] Figure 5 A situation in which beam misalignment occurs in a wireless communication system according to various embodiments of the disclosure is illustrated.

[0028] Figure 6 An operation method of a terminal in a wireless communication system according to various embodiments of the disclosure is illustrated.

[0029] Figure 7a An operation method for detecting beam misalignment based on a measurement pattern in a wireless communication system according to various embodiments of the disclosure is illustrated.

[0030] Figure 7b An example of beam misalignment detection based on a measurement pattern in a wireless communication system according to various embodiments of the disclosure is illustrated.

[0031] Figure 8a An operation method for detecting beam misalignment based on a measurement value order in a wireless communication system according to various embodiments of the disclosure is illustrated.

[0032] Figure 8b An example of beam misalignment detection based on a measurement value order in a wireless communication system according to various embodiments of the disclosure is illustrated.

[0033] Figure 8c Another example of beam misalignment detection based on a measurement value order in a wireless communication system according to various embodiments of the disclosure is illustrated.

[0034] Figure 8d An operation method for grouping measurement values in a wireless communication system according to various embodiments of the disclosure is illustrated.

[0035] Figure 8e An example of beam misalignment detection based on an order of measurement value groups in a wireless communication system according to various embodiments of the disclosure is illustrated.

[0036] Figure 9 A state transition diagram regarding beam misalignment in a wireless communication system according to various embodiments of the disclosure is illustrated.

[0037] Figure 10a An operation method for power control based on beam misalignment detection in a wireless communication system according to various embodiments of the disclosure is illustrated.

[0038] Figure 10b And Figure 10c An example of power control based on beam misalignment detection in a wireless communication system according to various embodiments of the disclosure is illustrated.

[0039] Figure 11a And Figure 11b A supported reference signal transmission scheme in a wireless communication system according to various embodiments of the disclosure is illustrated.

[0040] Figure 11c A signal exchange of a beam recovery procedure using dense reference signal transmission in a wireless communication system according to various embodiments of the disclosure is illustrated.

[0041] Figure 12a An operation method for recovering a beam using previous measurement results in a wireless communication system according to various embodiments of the disclosure is illustrated.

[0042] Figure 12b An operation method for recovering a beam using previous measurement results or using new measurements in a wireless communication system according to various embodiments of the disclosure is illustrated.

[0043] Figure 12c An example of beam recovery using previous measurement results in a wireless communication system according to various embodiments of the disclosure is illustrated.

[0044] Figure 13a An operation method for recovering a beam using sensor values in a wireless communication system according to various embodiments of the disclosure is illustrated.

[0045] Figure 13b An example of sensor value change based on movement in a wireless communication system according to various embodiments of the disclosure is illustrated.

[0046] Figure 13c AndFigure 13d A sensor installation example in a wireless communication system according to various embodiments of the disclosure is illustrated. DETAILED DESCRIPTION

[0047] The terms used in the disclosure are used to describe specific embodiments and are not intended to limit the scope of other embodiments. The singular form can include plural forms unless it is clearly different. All the terms used herein, including technical and scientific terms, can have the same meaning as the terms commonly understood by a person skilled in the art to which the disclosure belongs. Among the terms used in the disclosure, the terms defined in a general dictionary can be interpreted to have the same or similar meaning as in the context of the relevant technology, and unless clearly defined in the disclosure, it should not be ideally or excessively interpreted as a formal meaning. In some cases, even the terms defined in the disclosure should not be interpreted to exclude embodiments of the disclosure.

[0048] In various embodiments of the disclosure to be described below, a hardware method is described as an example. However, since various embodiments of the disclosure include a technology using hardware and software, various embodiments of the disclosure do not exclude a software-based method.

[0049] Hereinafter, various embodiments of the disclosure provide an apparatus and method for detecting beam misalignment in a wireless communication system. In addition, the disclosure relates to an apparatus and method for beam recovery in the case of beam misalignment in a wireless communication system.

[0050] The terms indicating a signal, the terms indicating a channel, the terms indicating control information, the terms indicating a network entity, and the terms indicating an apparatus component used in the following description are for explanation. Therefore, the disclosure is not limited to the terms to be described, and other terms having the same technical meaning can be used.

[0051] As an example, the disclosure provides various embodiments using terms used in some communication standards, for example, a long term evolution (LTE) system and a long term evolution-advanced (LTE-A). Various embodiments of the disclosure can be easily modified and applied to other communication systems.

[0052] Figure 1 A wireless communication system according to various embodiments of the disclosure is illustrated. Figure 1 The base station 110, the terminal 120, and the terminal 130 are depicted as some nodes using a radio channel in a wireless communication system.

[0053] The base station 110 is a network infrastructure that provides radio access to the terminals 120 and 130. The base station 110 has a coverage area defined as a geographical area based on a signal transmission distance. The base station 110 can be referred to as an access point (AP), an eNodeB (eNB), a fifth generation node (5G node), a wireless point, a transmission / reception point (TRP), or the like.

[0054] The terminals 120 and 130 are both devices used by users and communicate with the base station 110 through a radio channel. In some cases, at least one of the terminals 120 and 130 performs machine type communication (MTC) and can not be carried by a user. Both the terminals 120 and 130 can be referred to as user equipment (UE), a mobile station, a subscriber station, a remote terminal, a wireless terminal, or a user device.

[0055] The base station 110, the terminal 120, and the terminal 130 can transmit and receive radio signals in a millimeter wave (mmWave) band (e.g., 28 GHz, 30 GHz, 60 GHz). In this process, in order to improve channel gain, the base station 110, the terminal 120, and the terminal 130 can perform beamforming. Here, beamforming can include transmission beamforming and reception beamforming. That is, the base station 110, the terminal 120, and the terminal 130 can apply directivity to transmit or receive a signal. To this end, the base station 110, as well as the terminals 120 and 130, can select service beams 112, 113, 121, and 131 through a beam search process.

[0056] Figure 2 A configuration of a base station in a wireless communication system according to various embodiments of the disclosure is illustrated. The term used hereinafter, such as “… part” or “…er”, denotes a unit for processing at least one function or operation, and can be implemented using hardware, software, or a combination of hardware and software.

[0057] Referring to Figure 2 The base station 110 includes a wireless communication unit 210, a backhaul communication unit 220, a storage unit 230, and a controller 240.

[0058] The wireless communication unit 210 can perform a function for transmitting and receiving a signal through a radio channel. For example, the wireless communication unit 210 performs a conversion function between a baseband signal and a bit string according to a physical layer standard of a system. For example, in data transmission, the wireless communication unit 210 generates complex symbols by encoding and modulating a transmission bit string. Also, in data reception, the wireless communication unit 210 recovers a reception bit string by demodulating and decoding a baseband signal. Also, the wireless communication unit 210 up-converts a baseband signal to a radio frequency (RF) band signal, transmits via an antenna, and down-converts an RF band signal received via an antenna to a baseband signal.

[0059] To this end, the wireless communication unit 210 can include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a digital-to-analog converter (DAC), an analog-to-digital converter (ADC), etc. Further, the wireless communication unit 210 can include a plurality of transmission and reception paths. Further, the wireless communication unit 210 can include at least one antenna array including a plurality of antenna elements. In terms of hardware, the wireless communication unit 210 can include a digital unit and an analog unit, and the analog unit can include a plurality of sub-units according to operating power and operating frequency.

[0060] The wireless communication unit 210 transmits and receives a signal as described above. Accordingly, the wireless communication unit 210 can be referred to as a transmitter, a receiver, or a transceiver. Further, in the following, transmission and reception over a wireless channel are used as a meaning including the above-described processing of the wireless communication unit 210.

[0061] The backhaul communication unit 220 provides an interface for communication with other nodes in a network. That is, the backhaul communication unit 220 converts a bit string transmitted from the base station to another node (e.g., to another access node, another base station, an upper node, or a core network) into a physical signal, and converts a physical signal received from another node into a bit string.

[0062] The storage unit 230 stores basic programs, application programs, and data such as setting information for operating the base station 110. The storage unit 230 can include a volatile memory, a non-volatile memory, or a combination of the volatile memory and the non-volatile memory. The storage unit 230 provides stored data at the request of the controller 240.

[0063] The controller 240 controls the general operation of the base station. For example, the controller 240 transmits and receives a signal through the wireless communication unit 210 or the backhaul communication unit 220. Further, the controller 240 records and reads data in and from the storage unit 230. To this end, the controller 240 can include at least one processor. For example, the controller 240 can control the base station 110 to perform operations to be explained according to various embodiments.

[0064] Figure 3 A configuration of a terminal in a wireless communication system according to various embodiments of the disclosure is illustrated. The term such as "…part" or "…er" used in the following denotes a unit for processing at least one function or operation, and can be implemented using hardware, software, or a combination of hardware and software.

[0065] Referring to Figure 3 The terminal 120 includes a communication unit 310, a storage unit 320, and a controller 330.

[0066] The communication unit 310 can perform a function for transmitting and receiving signals over a radio channel. For example, the communication unit 310 performs a conversion function between a baseband signal and a bit string according to a physical layer standard of a system. For example, in data transmission, the communication unit 310 generates complex symbols by encoding and modulating a transmission bit string. Also, in data reception, the communication unit 310 recovers a reception bit string by demodulating and decoding a baseband signal. Also, the communication unit 310 up-converts a baseband signal to an RF band signal, transmits via an antenna, and down-converts an RF band signal received via an antenna to a baseband signal. For example, the communication unit 310 can include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, etc.

[0067] Also, the communication unit 310 can include a plurality of transmission and reception paths. Also, the communication unit 310 can include at least one antenna array including a plurality of antenna elements. In terms of hardware, the communication unit 310 can include a digital circuit and an analog circuit (e.g., an RF integrated circuit (RFIC)). Here, the digital circuit and the analog circuit can be implemented as a single package. Also, the communication unit 310 can include a plurality of RF chains. Also, the communication unit 310 can perform beamforming.

[0068] The communication unit 310 transmits and receives signals as described above. Accordingly, the communication unit 310 can be referred to as a transmitter, a receiver, or a transceiver. Also, in the following description, transmission and reception over a radio channel are used as a meaning including the above-described processing of the communication unit 310.

[0069] The storage unit 320 stores a basic program for operating the terminal 120, an application program, and data such as setting information. The storage unit 320 can include a volatile memory, a non-volatile memory, or a combination of a volatile memory and a non-volatile memory. The storage unit 320 provides stored data according to a request of the controller 330.

[0070] The controller 330 controls a general operation of the terminal 120. For example, the controller 330 transmits and receives signals through the communication unit 310. Also, the controller 330 records and reads data in and from the storage unit 320. To this end, the controller 330 can include at least one processor or microprocessor, or can be a part of a processor. A part of the communication unit 310 and the controller 330 can be referred to as a communication processor (CP). Specifically, the controller 330 can control the terminal 120 to detect beam misalignment and perform a beam recovery procedure according to various embodiments to be described. For example, the controller 330 can control the terminal to perform operations to be explained according to various embodiments.

[0071] Figures 4a to 4cA configuration of a communication unit in a wireless communication system according to various embodiments of the disclosure is illustrated. Figures 4a to 4c An example of a detailed configuration of the wireless communication unit 210 or Figure 2 the communication unit 310 is depicted. Figure 3 More specifically, Figures 4a to 4c An example of a detailed configuration of the wireless communication unit 210 or Figure 2 the communication unit 310 is depicted. Figure 3 An example of a detailed configuration of the wireless communication unit 210 or

[0072] Referring to Figure 4a , the wireless communication unit 210 or the communication unit 310 includes an encoder and modulator 402, a digital beamformer 404, a plurality of transmission paths 406-1 to 406-N, and an analog beamformer 408.

[0073] The encoder and modulator 402 performs channel coding. For the channel coding, at least one of a low-density parity-check (LDPC) code, a convolutional code, and a polar code can be used. The encoder and modulator 402 generates modulation symbols through constellation mapping.

[0074] The digital beamformer 404 performs beamforming on digital signals (e.g., modulation symbols). To this end, the digital beamformer 404 multiplies the modulation symbols by beamforming weights. Here, the beamforming weights are used to change the amplitude and phase of the signals, and can be referred to as a precoding matrix, a precoder, etc. The digital beamformer 404 outputs the digitally beamformed modulation symbols to the plurality of transmission paths 406-1 to 406-N. In this way, according to multiple-input multiple-output (MIMO) transmission, the modulation symbols can be multiplexed or the same modulation symbols can be provided to the plurality of transmission paths 406-1 to 406-N.

[0075] The plurality of transmission paths 406-1 to 406-N converts the digitally beamformed digital signals into analog signals. To this end, each of the plurality of transmission paths 406-1 to 406-N can include an inverse fast Fourier transform (IFFT) operator, a cyclic prefix (CP) adder, a DAC, and an up-conversion converter. The CP adder is used for an orthogonal frequency division multiplexing (OFDM) scheme, and can be excluded if another physical layer scheme (e.g., filter bank multi-carrier (FBMC)) is applied. That is, the plurality of transmission paths 406-1 to 406-N provides independent signal processing for a plurality of streams generated through digital beamforming. Notably, according to an embodiment, some components of the plurality of transmission paths 406-1 to 406-N can be commonly used.

[0076] The analog beamformer 408 performs beamforming on the analog signals. To this end, the digital beamformer 404 multiplies the analog signals by beamforming weights. Here, the beamforming weights are used to change the amplitude and phase of the signals. More specifically, according to the connection structure between the plurality of transmission paths 406-1 to 406-N and the antenna, the analog beamformer 408 can be configured as shown in Figure 4b or Figure 4c

[0077] Referring to Figure 4b , the signals input to the analog beamformer 408 are converted in phase / amplitude, amplified, and then transmitted via the antenna. In this way, the signals of each path are transmitted through different antenna groups, i.e., antenna arrays. For the signals input in the first path, the signals are converted into signal strings having different or the same phase / amplitude by the phase / amplitude converters 412-1-1 to 412-1-M, amplified by the amplifiers 414-1-1 to 414-1-M, and then transmitted via the antenna.

[0078] Referring to Figure 4c , the signals input to the analog beamformer 408 are converted in phase / amplitude, amplified, and then transmitted via the antenna. In this way, the signals of each path are transmitted through the same antenna group, i.e., the same antenna array. For the signals input in the first path, the signals are converted into signal strings having different or the same phase / amplitude by the phase / amplitude converters 412-1-1 to 412-1-M, and amplified by the amplifiers 414-1-1 to 414-1-M. Next, in order to be transmitted via a single antenna array, the amplified signals are added by the antenna element-based adders 416-1 to 416-M, and then transmitted via the antenna.

[0079] Figure 4b depicts an example in which each transmission path uses an independent antenna array, Figure 4c depicts an example in which the transmission paths share one antenna array. However, according to another embodiment, some transmission paths can use independent antenna arrays, while the remaining transmission paths can share one antenna array. In addition, according to still another embodiment, by applying a switchable structure between the transmission paths and the antenna array, a structure that is adaptively changed according to circumstances can be used.

[0080] Figure 5 shows a case in which beam misalignment occurs in a wireless communication system according to various embodiments of the disclosure.

[0081] Referring to Figure 5 ​, the base station 110 and the terminal 120 use the best beam as a serving beam through a beam search procedure. In this procedure, rotation or repositioning of the terminal 120 can occur. In this case, if the direction of the beam set at the terminal 120 is not changed, then the absolute direction of the beam is also changed according to the rotation or repositioning of the terminal 120. Accordingly, the beam of the terminal 120 can not face the base station 110. That is, the beam of the terminal 120 is no longer the best beam, and this state is referred to as beam misalignment in the disclosure.

[0082] As described before, the beam misalignment indicates a state in which the beam determined through the previous beam training procedure is no longer the best beam due to rotation and repositioning of the terminal 120 or a change in a channel environment. If the beam misalignment occurs, then a considerable loss of link budget can occur until a new best beam is searched through the next beam training procedure. Accordingly, transmission and reception of data can be difficult to proceed. For example, if the beam width is 15°, then, in the case of beam misalignment within 7°, a link budget loss of about 2 to 3 dB is expected, and, in the case of beam misalignment exceeding 7°, a link budget loss of about 10 to 20 dB is expected.

[0083] If the beam misalignment occurs as Figure 5 shown, the communication quality can be degraded unless the serving beam is appropriately changed. However, the degradation of the communication quality does not necessarily indicate the beam misalignment. For example, the serving beam is the best beam, but the communication quality can be lowered due to interference, fading, etc. That is, if only the communication quality or the channel quality is relied on, there is a possibility that the beam misalignment is erroneously determined. Accordingly, the disclosure explains various embodiments for more accurately detecting the beam misalignment.

[0084] Figure 6 An operation method of a terminal in a wireless communication system according to various embodiments of the disclosure is illustrated. Figure 6 An operation method of beam misalignment detection of the terminal 120 is illustrated.

[0085] Referring to Figure 6 In step 601, the terminal receives a reference signal beamformed with a plurality of transmission beams in a first period. Here, the first period is one of periods in which the base station repeatedly transmits a reference signal for beam search, and includes at least one time interval (e.g., a subframe). That is, the base station periodically or based on an event scans the reference signal. At this time, the terminal performs reception beamforming using at least one reception beam. Accordingly, the terminal can obtain a measurement value for each reception beam. Here, the measurement value is a reception strength of the reference signal, and can be referred to as a "reference signal received power (RSRP)". Using the measurement value, the terminal can determine its serving reception beam.

[0086] Next, in step 603, the terminal receives a reference signal for beamforming using multiple transmit beams in the second cycle. Here, the second cycle is one of the cycles in which the base station repeatedly transmits the reference signal for beam searching, and the second cycle arrives after at least one time interval from the first cycle. That is, during communication, if the cycle in which the base station transmits the reference signal arrives, the terminal receives the reference signal transmitted from the base station. At this time, the terminal uses at least one receive beam to perform receive beamforming. Therefore, the terminal can obtain two different sets of measurements from the cycle in which the serving beam is determined and from subsequent cycles.

[0087] Next, in step 605, the terminal determines whether beam misalignment has occurred based on measurements obtained for the first period and measurements obtained for the second period. That is, the terminal can determine whether beam misalignment has occurred by comparing sets of measurements of at least one received beam and two or more transmitted beams obtained at different times. Here, the compared measurements may or may not include measurements of the serving beam. If there is no similarity (or similarity) between the sets of measurements, the terminal determines that beam misalignment has occurred. The rules used to determine the presence or absence of similarity can be defined in various ways. For example, the rules for determining similarity can be defined based on at least one of the measurements, the order of the measurements, and statistical data of the measurements.

[0088] according to Figure 6 The embodiments described herein can detect beam misalignment based on sets of measurements of the same beam pair acquired at two different times. Since the base station repeatedly scans the reference signal for various purposes, the terminal can perform the measurements without additional overhead. Thus, measurements for comparison can be obtained simply by measuring at least one received beam.

[0089] exist Figure 6 In one embodiment, the serving receive beam is determined by a measurement obtained from the reference signal received in step 601. However, according to another embodiment, step 601 can be performed simultaneously with the determination of the serving beam. In this case, the measurement compared in step 605 can be a measurement taken when the serving beam was determined, or a measurement taken from a subsequently received reference signal (e.g., the reference signal received in step 601).

[0090] exist Figure 6In an embodiment of the present disclosure, the compared measurement values include measurement values of at least one receive beam and a plurality of transmit beams. That is, beam misalignment detection can be performed using only one receive beam. However, according to another embodiment, misalignment detection can be performed using measurement values of one base station transmit beam and a plurality of terminal receive beams. That is, misalignment detection according to another embodiment can be performed using only one transmit beam. Although the various embodiments to be described below are described assuming that at least one receive beam and a plurality of transmit beams are used for explanation purposes, these embodiments can be easily applied even if a plurality of receive beams are used.

[0091] Figure 7a An operation method for detecting beam misalignment based on a measurement pattern in a wireless communication system according to various embodiments of the present disclosure is illustrated. Figure 7a An operation method of a terminal 120 is illustrated.

[0092] Referring to Figure 7a In step 701, the terminal receives a reference signal using an arbitrary receive beam. In other words, the terminal performs receive beamforming on the reference signal using an arbitrary receive beam. The terminal receives the reference signal transmitted from the base station using an arbitrary receive beam for a certain beam full-scan period. At this time, the terminal receives all of the reference signals or part of the reference signals transmitted during the entire scan period.

[0093] In step 703, the terminal obtains pattern information of the measurement values. That is, the terminal measures the reception strength of the reference signal received in step 701 and stores a pattern of the measurement values. Here, the pattern of the measurement values can be defined as a relative amplitude relationship of the measurement values, i.e., a ratio of the remaining measurement values to one measurement value. Alternatively, the pattern of the measurement values can be defined as an order of the transmit beams ordered in ascending or descending order of the measurement values. At this time, the pattern of the measurement values is determined for each receive beam. Hereinafter, the pattern of the measurement values is referred to as a "measurement pattern".

[0094] In step 705, the terminal determines whether a previously obtained measurement pattern of the current receive beam exists. In other words, for the receive beam used in step 701, the terminal determines whether another measurement pattern obtained before the measurement pattern obtained in step 703 exists. If the previously obtained measurement pattern does not exist, the terminal returns to step 701.

[0095] On the contrary, if the previously obtained measurement pattern exists, in step 707, the terminal compares the two measurement patterns of the same receive beam. That is, the terminal compares the measurement pattern obtained in step 703 with the previously obtained measurement pattern.

[0096] In step 709, the terminal determines whether the similarity between the measurement patterns is less than a threshold. According to a certain embodiment, the similarity can be defined in different ways. For example, the similarity can be determined based on at least one of a difference between the ratios of the same transmission beam and an order in which the ratios form each measurement pattern.

[0097] If the similarity is less than the threshold, in step 711, the terminal determines that beam misalignment occurs. In other words, the terminal determines that the current serving beam is not the best beam. On the contrary, if the similarity is equal to or greater than the threshold, the terminal determines that no beam misalignment occurs and returns to step 701.

[0098] Referring to Figure 7b Explanation of Reference Figure 7a Specific examples of the described embodiments. Figure 7b An example of beam misalignment detection based on measurement patterns in a wireless communication system according to various embodiments of the disclosure is shown.

[0099] Referring to Figure 7b For the nth full scan period 710, the base station 110 repeatedly transmits the beamformed reference signal. At this time, the terminal 120 receives the reference signal using a plurality of reception beams. For the period 710, the terminal 120 acquires a plurality of measurement patterns, including measurement pattern 712 and measurement pattern 714. Next, for the (n+1)th full scan period 720, the base station 110 repeatedly transmits the beamformed reference signal. At this time, the terminal 120 obtains a measurement pattern 722 of at least one reception beam. In this process, because there is a measurement pattern 714 for the same reception beam as the measurement pattern 722, the terminal 120 compares the measurement pattern 722 and the measurement pattern 714. In Figure 7b In the example of FIG. 7, the measurement pattern 714 and the measurement pattern 722 exhibit different patterns. In this case, the terminal can determine that the similarity is less than the threshold and declare beam misalignment.

[0100] According to the reference Figure 7a and Figure 7b According to the embodiments described in the reference

[0101] In Figure 7a and Figure 7bIn an embodiment of the disclosure, the terminal declares beam misalignment due to a change in the measurement pattern. However, according to another embodiment, in order to more accurately detect beam misalignment, the terminal can declare beam misalignment only when the change in the measurement pattern is repeated a certain number of times. In this case, the accuracy of beam misalignment detection can be improved even if the number of transmission beams used by the base station is small.

[0102] In addition, in order to more accurately detect beam misalignment, the terminal can determine the change in the measurement pattern in two or more stages according to a criterion. Hereinafter, embodiments for determining the change in the measurement pattern in stages are described by referring to FIGS. 8 to 11. Figures 8a to 8e

[0103] Figure 8a An operation method for detecting beam misalignment based on a sequence of measurement values in a wireless communication system according to various embodiments of the disclosure is illustrated. Figure 8a An operation method of a terminal 120 is illustrated.

[0104] Referring to FIG. 8, Figure 8a In step 801, the terminal receives a beamformed reference signal. At this time, the terminal performs reception beamforming using at least one reception beam. In this process, the terminal has a set of measurement values for the at least one reception beam before step 801. By using the reference signal received in step 801, the terminal obtains another set of measurement values for the at least one reception beam. Hereinafter, the disclosure is described based on a set of measurement values for one reception beam for convenience of explanation.

[0105] Next, in step 803, the terminal calculates a change in the measurement values. That is, the terminal calculates a difference between the two sets of measurement values. Here, the change can be defined in different ways. For example, the change can be a sum or an average of the differences in the measurement values for each transmission beam. At this time, at least one of a maximum value and a minimum value of the measurement values can be excluded from the sum or the average calculation. For example, the change can be determined based on Equation 1.

[0106] ΔX t = |X t - X t-1 |

[0107] Optionally, if N is 8 or more, Max, Min deviation is removed from ΔX t (1)

[0108]

[0109] In Equation 1, ΔX t denotes a difference between the t-th measurement value and the (t-1)-th measurement value, X t denotes the t-th measurement value, ​denotes an average of the difference of the measured values, and N denotes the number of measured values for the average determination.

[0110] Next, in step 805, the terminal determines whether the change is greater than a threshold. The change greater than the threshold can mean that the measurement pattern can change.

[0111] If the change is less than or equal to the threshold, in step 807, the terminal initializes a counter of the measurement pattern change. The counter of the measurement pattern change is a variable for counting the number of times of the measurement pattern change. Next, the terminal returns to step 801. Hereinafter, the counter for the measurement pattern change is referred to as a "measurement pattern change counter".

[0112] On the contrary, if the 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 order or descending order according to the magnitude of the measured values included in the two groups of measured values, and identifies whether the order of the arranged transmission beams matches. That is, among the two measured values, the terminal identifies whether the transmission beam having the same greatest measured value matches, and whether the transmission beam having the second greatest measured value matches.

[0113] Next, in step 811, the terminal identifies whether the order of the measured values changes. If the order of the measured values does not change, that is, if the order of the measured values is the same, the terminal initializes the measurement pattern change counter in step 807, and returns to step 801.

[0114] On the contrary, if the order of the measured values changes, in step 813, the terminal increases the measurement pattern change counter. That is, the terminal determines the change of the measurement pattern, and records the change count.

[0115] Next, in step 815, the terminal determines whether the measurement pattern change counter is greater than or equal to a threshold. That is, if the measurement pattern change of a certain count occurs, the terminal compares the measurement pattern change counter with the threshold in order to declare the beam misalignment. Notably, if the threshold is set to 1, it is possible to declare the beam misalignment with only one measurement pattern change. If the measurement pattern change counter is less than the threshold, the terminal determines that the beam misalignment does not occur, and returns to step 801.

[0116] On the contrary, if the measurement pattern change counter is greater than or equal to the threshold, in step 817, the terminal determines the beam misalignment. That is, the terminal determines that the beam misalignment has occurred.

[0117] Reference will now be made to Figure 8b descriptions Figure 8b of specific examples of embodiments. Figure 8b showing a beam misalignment, Figure 8c showing no beam misalignment.

[0118] Figure 8b Examples of beam misalignment detection based on measurement order in wireless communication systems according to various embodiments of the present disclosure are shown. (Refer to...) Figure 8b For the nth full scan cycle 810, base station 110 repeatedly transmits the beamformed reference signal. At this time, terminal 120 receives the reference signal using multiple receive beams. During cycle 810, terminal 120 acquires measurement value group 812. Next, for the (n+1)th full scan cycle 820, base station 110 repeatedly retransmits the beamformed reference signal. At this time, terminal 120 acquires measurement value group 822. Measurement value group 812 and measurement value group 822 exhibit a difference in variation. The order of the measurement values ​​in measurement value group 812 is "2-3-1-5-6-4", while the order of the measurement values ​​in measurement value group 822 is "5-6-4-2-3-1", which is different. Therefore, because the variation exceeds a threshold and the order is different, misalignment is declared.

[0119] Figure 8c Another example of beam misalignment detection based on measurement order in a wireless communication system according to various embodiments of this disclosure is shown. (Refer to...) Figure 8c For the nth full scan cycle 810, base station 110 repeatedly transmits the beamformed reference signal. At this time, terminal 120 receives the reference signal using multiple receive beams. During cycle 810, terminal 120 acquires measurement value group 814. Next, for the (n+1)th full scan cycle 820, base station 110 repeatedly retransmits the beamformed reference signal. At this time, terminal 120 acquires measurement value group 824. Measurement value group 814 and measurement value group 824 show a difference in variation. The order of the measurement values ​​in measurement value group 814 is '2-1-3-5-6-4', and the order of the measurement values ​​in measurement value group 824 is '2-1-3-5-6-4', which is the same order. Therefore, although the variation is greater than a threshold, i.e., the offset is different, the identical order does not indicate beam misalignment.

[0120] According to reference Figures 8a to 8c The described embodiments can detect beam misalignment not caused by interference or paging. Furthermore, implementation and determination accuracy are ensured through a two-stage determination considering both measurement variations and sequence. Additionally, accuracy is ensured even when using a small transmit beam from the base station due to the use of a pattern variation counter.

[0121] In this case, in order to prevent inaccurate determination of beam misalignment, it is necessary to consider measurement error when determining the order of measurement values. If repositioning or rotation of the terminal does not occur, but the difference in measurement values between the transmission beams is not significant, the order can be reversed due to small measurement error or randomness. Therefore, in order to prevent false beam misalignment declaration due to measurement error, the following describes an embodiment in which measurement values are grouped. Figure 8d and Figure 8e An embodiment employing grouping of measurement values is described.

[0122] Figure 8d An operation method for grouping measurement values in a wireless communication system according to various embodiments of the disclosure is illustrated. Figure 8d An operation method of a terminal 120 is illustrated.

[0123] Referring to Figure 8d , in step 851, the terminal receives a beamformed reference signal. At this time, the terminal performs reception beamforming using at least one reception beam. Using the received reference signal, the terminal obtains different measurement value groups for the at least one reception beam. Hereinafter, for the purpose of description, the disclosure provides an explanation based on a measurement value group for one reception beam.

[0124] Next, in step 853, the terminal orders the transmission beams based on the measurement values. That is, the terminal identifies a transmission beam corresponding to the largest measurement value, a transmission beam corresponding to the second largest measurement value, and so on. Accordingly, the transmission beams are ordered in the order of measurement value size.

[0125] Next, in step 855, the terminal identifies whether the difference in measurement values is less than a threshold value. That is, for each transmission beam pair having adjacent order in the ordered transmission beams, the terminal identifies whether the difference in measurement values is less than a threshold value. Here, the threshold value can be adjusted based on measurement error or randomness of the reference signal.

[0126] If the difference in measurement values is less than the threshold value, in step 857, the terminal sets the same rank by grouping the corresponding transmission beam pair. In this way, three or more transmission beams can be set to the same rank based on the difference in measurement values of the transmission beams of the next rank.

[0127] If the difference in measurement values is greater than or equal to the threshold value, in step 859, the terminal sets the next lower rank. That is, the terminal sets two transmission beams of the corresponding transmission beam pair to different ranks.

[0128] Now referring to Figure 8e a specific example of beam misalignment determination according to the embodiment described in Figure 8d is explained. Figure 8eAn example of beam misalignment detection based on order of measurement value sets in a wireless communication system according to various embodiments of the disclosure is shown.

[0129] Referring to Figure 8e For the nth full scan period 810, the base station 110 repeatedly transmits the beamformed reference signal. At this time, the terminal 120 receives the reference signal using a plurality of reception beams. During the period 810, the terminal 120 acquires the measurement value set 816. Next, for the (n+1)th full scan period 820, the base station 110 repeatedly retransmits the beamformed reference signal. At this time, the terminal 120 obtains the measurement value set 826. The measurement value set 816 and the measurement value set 826 show a change difference. The order of the measurement values of the measurement value set 816 is "2-1-3-5-6-4", and the order of the measurement values of the measurement value set 826 is "2-3-1-5-6-4", the orders are different from each other. However, since the difference between the measurement values of the transmission beam #1 and the transmission beam #3 is less than the threshold value, the transmission beam #1 and the transmission beam #3 are grouped together, thus having the same level. In this case, the order difference of "1-3" and "3-1" does not affect the determination of the measurement pattern change. Therefore, the beam misalignment is not declared. Thereby, it is possible to prevent the erroneous determination of the beam misalignment due to the opposite order caused by the measurement error or randomness.

[0130] Figure 9 A state transition diagram regarding beam misalignment according to various embodiments of the disclosure in a wireless communication system is shown. Figure 9 A state transition diagram of a beam misalignment determination procedure employing a 2-level measurement pattern change considering change and order is shown.

[0131] Referring to Figure 9 , the initial state is in beam alignment 910. If the change of the measurement value is greater than the threshold value, the state transitions to change measurement value 920. In the change measurement value 920, if the order change is determined, the state transitions to change measurement pattern 930. At this time, even if the measurement pattern change occurs in less than the threshold number of consecutive periods, the change measurement pattern 930 is maintained. If the order change is not determined in less than the threshold number of consecutive periods, the state switches to change measurement value 920. In addition, if the change is below the threshold value or the order change is not determined in less than the threshold number of consecutive periods, the state transitions to beam alignment 910. If the measurement pattern change occurs in more than the threshold number of consecutive periods in the change measurement pattern 930, the state transitions to beam misalignment 940. In the beam misalignment 940, if the beam misalignment is recovered, the state returns to the beam alignment 910.

[0132] According to the various embodiments described above, beam misalignment can be detected. The result of the determination of the beam misalignment can be utilized differently. According to one embodiment, the determination of the beam misalignment can be used for power control of the receiving unit of the terminal 120. Specifically, the determination of the beam misalignment can be used for power control during operation in a discontinuous reception (DRX) mode. Here, the DRX mode is an operation mode that temporarily deactivates all or part of the receiving circuit by turning off, hibernating, etc. of the hardware of the physical layer while maintaining the connected state (i.e., active state in the upper layer (e.g., radio resource control (RRC) layer)) to temporarily deactivate all or part of the receiving circuit.

[0133] If operating in the DRX mode, the on-duration and the sleep duration are repeated according to a DRX cycle or DRX period. At this time, the terminal 120 receives a signal transmitted from the base station 110 by activating the receiving circuit for the on-duration, and deactivates the receiving circuit for the sleep duration. Here, activation can be referred to as wake-up, and deactivation can be referred to as hibernation. In a system that performs communication based on beamforming, the terminal 120 transmits feedback about a preferred beam to the base station 110 at least once during the DRX duration. The base station 110 can transmit downlink scheduling information during the on-duration.

[0134] At this time, even if activated during the on-duration, the terminal can not receive a signal if the beam is not aligned. Therefore, the terminal should activate the receiving circuit and then perform beam search before there is enough time for the signal to arrive during the on-duration. However, the beam used in the previous on-period is not always ineffective. Therefore, the terminal that activates the receiving circuit before there is enough time for the signal to arrive during the on-duration can control the subsequent operation state according to the determination of whether the beam is misaligned. Accordingly, referring to Figure 10a 、 Figure 10b and Figure 10c , the disclosure describes embodiments of controlling the receiving circuit according to the result of the beam misalignment detection during operation in the DRX mode.

[0135] Figure 10a An operation method of power control based on beam misalignment detection in a wireless communication system according to various embodiments of the disclosure is illustrated. Figure 10a An operation method of a terminal 120 is illustrated.

[0136] Referring to Figure 10a , in step 1001, the terminal enters a discontinuous operation mode (e.g., DRX mode). The DRX mode is entered under the control of the base station. That is, the terminal receives a message indicating entry into the DRX mode from the base station. Accordingly, the terminal operates the on-duration and the sleep duration according to the DRX cycle. For the sleep duration, the terminal can deactivate the entire or part of the receiving circuit.

[0137] In step 1003, the terminal determines whether the beam is misaligned for the sleep duration. According to an embodiment, the terminal can perform a beam measurement. That is, the terminal can temporarily activate the reception circuit in the sleep interval and receive a beamformed reference signal transmitted from the base station. That is, the terminal determines whether the beam misalignment occurs by comparing a new measurement value with a measurement value obtained from a previous on-duration or before entering the DRX mode. For example, according to one of the various embodiments described above, the terminal can determine whether the beam is misaligned. According to another embodiment, the terminal can determine whether the beam is misaligned by using a sensor of the terminal. To determine whether the beam is misaligned using the sensor, the terminal identifies whether the terminal is rotated or repositioned after the previous beam search. In this way, the time for determining whether the beam is misaligned is before a certain time before the on-duration, and the certain time is greater than or equal to the time taken to perform the beam recovery, i.e., the time required to realign the beam.

[0138] Next, in step 1005, the terminal identifies whether the beam misalignment occurs. If the beam misalignment occurs, in step 1007, the terminal performs a beam recovery procedure. According to a certain embodiment, the beam recovery procedure can be performed in various ways. For example, as the beam recovery procedure, the terminal can perform a beam search procedure. Alternatively, the terminal can perform the beam recovery procedure according to various embodiments described below.

[0139] On the contrary, if it is determined that the beam misalignment does not occur in step 1009, the terminal maintains the sleep state until the on-duration arrives. Here, "before the on-duration" indicates timing that takes into account the time required for normalizing the reception circuit. That is, because the beam is aligned without the beam misalignment, no additional beam recovery procedure is required. Accordingly, the terminal can reduce power consumption by maintaining the reception circuit in the deactivated state for the remaining sleep duration.

[0140] Reference will now be made to Figure 7b Exemplary embodiments described above are explained with Figure 10a Reference will now be made to Figure 10b and Figure 10c An example of power control based on beam misalignment detection in a wireless communication system according to various embodiments of the disclosure is shown.

[0141] Figure 10b A case where it is determined whether the beam is misaligned based on a beam measurement is shown. Reference will now be made to Figure 10bIf the on-duration ends, the terminal 120 enters the sleep duration and deactivates the reception circuit. At this time, before the time 1002 from the next on-duration Δt, the terminal temporarily activates the reception circuit and detects the beam misalignment. According to the detection result of the beam misalignment, the operation state of the reception circuit for the duration of the time 1002 can be changed.

[0142] Figure 10c A case where the beam is determined to be misaligned based on the sensor value is illustrated. Referring to Figure 10c If the on-duration ends, the terminal 120 enters the sleep duration and deactivates the reception circuit. At this time, before the time 1002 from the next on-duration Δt, the terminal detects the beam misalignment using the sensor value. According to the detection result of the beam misalignment, the operation state of the reception circuit for the duration of the time 1002 can be changed. If the beam is recovered as Figure 10c If the sensor is used as illustrated, the sleep state can be maintained for a longer time because the reception circuit does not need to be temporarily activated.

[0143] In the examples of Figure 10b and Figure 10c , if the beam misalignment occurs, the terminal 120 performs a beam recovery procedure. The beam recovery procedure can include the measurement of the beam to be described. However, in some embodiments, the beam can be recovered based on past beam measurement results or sensor values without the need for measurement of the beam. If the beam can be recovered without measurement of the beam, the terminal 120 that detects the beam misalignment can recover the beam and then maintain the sleep state. According to still another embodiment, if the beam recovery procedure based on the beam measurement is performed, the terminal 120 can maintain the sleep state for the remaining sleep duration if the beam recovery is completed before the on-duration arrives.

[0144] According to the embodiments described with reference to Figure 10a and Figure 10b , the sleep duration for deactivating the reception circuit during the DRX mode can be more effectively used. That is, according to the fast determination of the beam misalignment, the terminal can secure a longer sleep duration. At this time, if it is determined that the beam misalignment occurs, the terminal performs a beam recovery procedure for the remaining sleep duration. Hereinafter, the present disclosure describes various embodiments of the beam recovery.

[0145] The base station 110 according to various embodiments periodically or based on an event scans a reference signal for performing a beam search of the terminal 120. In this process, the base station 110 can support at least two or more reference signal transmission schemes. For example, the reference signal transmission schemes are illustrated in Figure 11a and Figure 11b Figure 11a and​Figure 11b Reference signal transmission schemes supported by a wireless communication system according to various embodiments of the disclosure are depicted.

[0146] Figure 11a A reference signal transmission scheme for beam search of a plurality of terminals including terminal 120 is shown. Referring to Figure 11a , base station 110 scans all transmission beams of base station 110 and repeatedly performs scanning of all transmission beams. In this case, the reference signal can be referred to as a "beam reference signal (BRS)". Thus, for each scan, terminal 120 can receive the reference signal by using a different reception beam, performing measurement for each combination of transmission beam and reception beam. Figure 11a Reference signal transmission of

[0147] Figure 11b A reference signal transmission scheme for beam search of a specific terminal (e.g., terminal 120) is shown. Referring to Figure 11b , base station 110 transmits a reference signal for terminal 120 for a specific duration (e.g., a subframe). In this case, the reference signal can be referred to as a "beam refinement reference signal (BRRS)". A downlink duration within the duration is allocated to all reference signals except for a control channel (e.g., a physical downlink control channel (PDCCH)). Here, the reference signal can be repeated a plurality of times (e.g., four times) within one symbol. At this time, base station 110 can scan all transmission beams or only scan some transmission beams. Figure 11b Reference signal transmission of

[0148] As described with reference to Figure 11a and Figure 11b , two or more reference signal transmission schemes can be supported. Figure 11a The scheme of Figure 11b can be performed on a plurality of terminals, but requires a longer time. In contrast, Figure 11c The above two reference signal transmission schemes can be operated as shown in

[0149] Figure 11c Signal exchanges for a beam recovery procedure using dense reference signal transmission in a wireless communication system according to various embodiments of the disclosure are shown. Figure 11c Signal exchanges between base station 110 and terminal 120 are shown.

[0150] Referring to Figure 11cIn steps 1101-1 to 1101-N, the base station 110 transmits a reference signal. The reference signal is scanned N times and transmitted through at least one subframe. In this way, the terminal 120 performs receive beamforming by using at least one receive beam for each scan. Accordingly, the terminal 120 can select an optimal beam as a serving beam. Here, the serving beam includes a serving transmission beam of the base station 110 and a serving reception beam of the terminal 120.

[0151] In step 1103, the terminal 120 transmits beam feedback informing the serving beam to the base station 110. Here, the beam feedback can 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 can be referred to as a "beam selection index (BSI)".

[0152] In step 1105, the terminal 120 detects beam misalignment. The terminal 120 can perform measurement on at least one received beam, compare the measurement value with a previously acquired measurement value, and then detect beam misalignment based on the comparison result. For example, according to one of the various embodiments described above, the terminal 120 can detect beam misalignment. Accordingly, the beam recovery procedure is as follows.

[0153] In step 1107, the terminal 120 transmits a BRRS request to the base station 110. In other words, when determining the occurrence of beam misalignment, the terminal 120 transmits a message requesting the base station 120 to transmit a specific reference signal to the terminal 120. That is, the beam recovery procedure is triggered by the terminal 120. Accordingly, in step 1109, the base station 110 transmits BRRS allocation information. Next, in step 1111, the base station 110 repeatedly transmits a reference signal, that is, a BRRS. Accordingly, the terminal 120 can re-determine an optimal beam. Next, in step 1113, the terminal 120 transmits BRRS feedback informing the serving beam to the base station 110.

[0154] According to the embodiments described with reference to Figures 11a to 11b , it is possible to address the beam misalignment situation. Specifically, for beam misalignment, beam recovery can be performed through dense reference signal transmission on the terminal. That is, detection of beam misalignment can be used as a condition for dense reference signal transmission such as a BRRS.

[0155] As Figure 11b indicated, the reference signal transmission scheme requires a shorter time than the scheme of Figure 11a , but still requires time to transmit a repeated reference signal for measurement. Accordingly, a procedure for recovering a beam in a shorter time is explained with reference to Figures 12a to 12c

[0156] Figure 12a ​An operation method of recovering a beam using previous measurement results in a wireless communication system according to various embodiments of the disclosure is illustrated. Figure 12a An operation method of a terminal 120 is illustrated.

[0157] Referring to Figure 12a In step 1201, the terminal detects beam misalignment. The terminal can perform measurement on at least one reception beam, compare the measurement value with a previously acquired measurement value, and then detect beam misalignment based on the comparison result. For example, the terminal can detect beam misalignment according to one of various embodiments as described above.

[0158] Next, in step 1203, the terminal identifies a previous measurement pattern similar to the current measurement pattern. That is, the terminal identifies a past measurement pattern similar to the measurement pattern obtained in the determination of beam misalignment of step 1201, that is, a measurement pattern that can not declare beam misalignment compared to the current measurement pattern. That is, the terminal can store and search information on the past measurement pattern.

[0159] Next, in step 1205, the terminal reuses a serving beam obtaining the identified previous measurement pattern. If the measurement patterns are similar, the same best beam can be expected. Accordingly, the terminal sets the serving beam having a similar measurement pattern to the current measurement pattern as the current serving beam. Here, the serving beam obtaining the previous measurement pattern can be a beam selected based on a measurement result corresponding to the previous measurement pattern, or a beam selected through beam recovery after beam misalignment is determined by the previous measurement pattern. At this time, according to another embodiment, the terminal can determine whether the use of the previous serving beam is still valid. For example, the terminal can determine the validity based on the time elapsed from when the previous measurement pattern is acquired.

[0160] According to the embodiment described with reference to Figure 12a A beam can be recovered without additional beam search. However, a previous measurement pattern similar to the current measurement pattern can not exist. Accordingly, according to another embodiment, as Figure 12b illustrated, an additional beam search can be considered together.

[0161] Figure 12b An operation method of recovering a beam using previous measurement results or using new measurement in a wireless communication system according to various embodiments of the disclosure is illustrated. Figure 12b An operation method of a terminal 120 is illustrated.

[0162] Referring to Figure 12bIn step 1251, the terminal detects beam misalignment. The terminal can perform measurement on at least one reception beam, compare the measurement value with a previously acquired measurement value, and then detect beam misalignment based on the comparison result. For example, the terminal can detect beam misalignment according to one of various embodiments as described above.

[0163] In step 1253, the terminal identifies whether there is a previous measurement pattern similar to the current measurement pattern. That is, the terminal identifies a past measurement pattern similar to the measurement pattern obtained when beam misalignment is determined, that is, a measurement pattern that can not declare beam misalignment compared to the current measurement pattern. That is, the terminal can store information on past measurement patterns and corresponding beams, and search using the measurement pattern.

[0164] If there is a previous measurement pattern similar to the current measurement pattern, in step 1255, the terminal sets a beam corresponding to the previous measurement pattern as a serving beam. If the measurement patterns are similar, the same best beam can be expected. Therefore, the terminal reuses the serving beam having a similar measurement pattern to the current measurement pattern without an additional beam search. In other words, the terminal sets the serving beam determined when the previous measurement pattern is obtained as the current serving beam.

[0165] 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 a beam search. To this end, the terminal can request the base station to transmit a reference signal. For example, the terminal can perform a beam recovery procedure according to the embodiments described with reference to FIGS. 11 to 14. Figure 11c

[0166] 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 result can be used for subsequent beam misalignment detection. In addition, if beam misalignment occurs later, the stored measurement result can be used for beam recovery.

[0167] In step 1261, the terminal sets a validity time window. Based on the assumption of similarity of the terminal location, it is possible to select a serving beam through similarity of the measurement pattern. Therefore, if the terminal moves and its relative position to the base station changes, even a beam corresponding to the same or similar measurement pattern can not be the best beam. Therefore, the validity of the past measurement record is limited, and the validity duration is managed through a validity time window. In this case, the validity time window can be defined as a fixed value, or can be dynamically adjusted based on the environment of the terminal (e.g., moving speed).

[0168] ​Next, in step 1263, the terminal sets the beam determined by the beam recovery procedure as a serving beam. That is, the terminal sets the best beam selected in step 1257 as the serving beam. Also, the terminal can transmit feedback information indicating the serving transmission beam of the base station.

[0169] In step 1265, the terminal performs communication by using the serving beam. Specifically, the terminal receives a data signal transmitted from the base station using the serving reception beam. Here, the reception of the data signal includes deciphering and decoding.

[0170] In step 1267, the terminal determines whether the beam misalignment is recovered. In other words, the terminal determines whether the serving beam set in step 1255 or step 1263 is the best beam, i.e., provides sufficient channel quality for communication. Whether the beam misalignment is recovered can be determined in different ways. For example, the terminal can determine whether the beam misalignment is recovered based on whether the decoding of the received data signal is successful. If the beam misalignment is recovered, the terminal returns to step 1251.

[0171] On the contrary, if the beam misalignment is not recovered, in step 1269, the terminal deletes the corresponding measurement pattern information and beam information. That is, even if the serving beam set in step 1255 or step 1263 does not recover the beam misalignment, this indicates that the corresponding measurement result is unreliable. Therefore, since the corresponding measurement result can not be used for subsequent beam misalignment determination or recovery, the terminal discards the corresponding measurement result.

[0172] Specific examples of the embodiments described with reference to Figure 12c will be explained with reference to Figure 12a or 12b. Figure 12c An example of beam recovery using previous measurement results in a wireless communication system according to various embodiments of the disclosure is shown.

[0173] With reference to Figure 12c , in the nth full scan duration 1210, the base station 110 repeatedly transmits beamformed reference signals. At this time, the terminal 120 receives the reference signals using a plurality of reception beams. Within the duration 1210, the terminal 120 obtains a plurality of measurement results, including a measurement result 1212 corresponding to the reception beam 1262. As such, the beam misalignment is determined, and the terminal 120 selects beam #k as a serving beam through a beam recovery procedure.

[0174] Next, in the (n+x)th full scan duration 1220, the base station 110 repeatedly retransmits beamformed reference signals. At this time, the terminal 120 obtains a measurement pattern 1222 of at least one reception beam. Next, the terminal 120 determines the occurrence of the beam misalignment and identifies a previous measurement pattern similar to the measurement pattern 1222. In this case, the terminal 120 identifies the measurement pattern 1212 as the previous measurement pattern.Figure 12c In this case, the measurement pattern 1212 obtained in the duration 1210 is similar to the measurement pattern 1222. Accordingly, without beam search, the terminal 120 will declare the beam #k selected via the recovery procedure as a serving beam by the beam misalignment in the duration 1210.

[0175] According to the embodiments described with reference to Figures 12a to 12c by using previous measurement results, beam recovery is feasible without a beam search procedure. Furthermore, the present disclosure now explains another embodiment for recovering a beam without beam search by referring to Figures 13a to 13d

[0176] Figure 13a An operation method of recovering a beam using a sensor value in a wireless communication system according to various embodiments of the present disclosure is illustrated. Figure 13a An operation method of a terminal 120 is illustrated.

[0177] Referring to Figure 13a In step 1301, the terminal detects a beam misalignment. The terminal can perform a measurement on at least one reception beam, compare the measurement value with a previously acquired measurement value, and then detect a beam misalignment based on the comparison result. For example, the terminal can detect a beam misalignment according to one of the various embodiments as described above.

[0178] In step 1303, the terminal determines a movement amount by using a sensor value. Here, the sensor value refers to a value indicating a physical change obtained by at least one sensor capable of measuring rotation and displacement of the terminal. For example, in order to determine the movement amount, at least one of a gyro sensor, an acceleration sensor, a compass sensor (Campus), and a gravity sensor (G sensor) can be used.

[0179] In step 1305, the terminal determines a new serving beam based on the movement amount. Based on the movement amount, i.e., rotation and displacement of the terminal, the terminal determines rotation / displacement of an antenna and selects a new serving beam to compensate for the rotation / displacement of the antenna. For example, referring to Figure 13b In the coordinates 1302 (X1, Y1, Z1) of the main gain direction of the current serving beam, the terminal can determine the coordinates 1304 (X2, Y2, Z2) of the new main gain direction = (X1+dx, dy+Y1, Z1+dz) by reflecting the movement amount (dX, dY, dZ) measured by the sensor. The terminal can select a beam having the most similar direction to the new main gain direction as a serving beam.

[0180] In Figure 13a ​In an embodiment of the above-described various embodiments, the beam misalignment detection of step 1301 is performed using the measurement value of the reference signal. However, according to another embodiment, the detection of the beam misalignment can also be performed based on the sensor value. Specifically, if the movement amount is greater than a threshold value measured by the sensor, the terminal can declare the beam misalignment. According to still another embodiment, in order to achieve more accurate beam misalignment detection, the beam misalignment can be detected based on the measurement value of the reference signal as well as the sensor value. In this case, even if the activity level of the sensor is not measured correctly, the beam misalignment can be more accurately detected if the change in the measurement pattern is used together.

[0181] According to the embodiment described with reference to Figure 13a , the beam recovery is feasible without the beam search procedure by using the sensor value. If the beam misalignment detection or the beam recovery is performed using the sensor value as shown in Figure 13a , the installation position of the sensor can affect the accuracy. For example, if the sensor and the antenna are spaced apart by a certain distance, the movement amount obtained by the sensor value can be different from the movement amount of the antenna. In order to overcome the difference in the movement amount based on the sensor installation position, the structure of Figure 13c or Figure 13d can be applied. Figure 13c and Figure 13d show a sensor installation example in a wireless communication system according to various embodiments of the disclosure.

[0182] Referring to Figure 13c , the terminal includes an AP 1310, baseband (BB) circuitry 1320, an RFIC 1330, and an antenna 1340, and a sensor 1350 is installed in the RFIC 1330. Since the path loss is quite large according to the characteristics of the millimeter wave, the RFIC 1330 can be disposed close to the antenna 1340. Therefore, if the sensor 1350 is installed in the RFIC 1330, the sensor 1350 is physically installed close to the antenna 1340. In this case, the movement amount determined based on the measurement value measured by the sensor 1350 can be considered as the movement of the antenna 1340. At this time, the sensor 1350 can be an additional component for measuring the movement of the antenna 1340 separately from the sensor for other purposes.

[0183] Referring to Figure 13d , the terminal includes an AP 1310, BB circuitry 1320, an RFIC 1330, and an antenna 1340, and includes a sensor 1350 and a sensor hub 1360. Unlike the embodiment of Figure 13c , the sensor 1350 is installed in the RFIC 1330, and the sensor hub 1360 is installed in the BB circuitry 1320. Figure 13dThe structure does not specify the position of the sensor 1350. Notably, the AP 1310 or another processor performs calibration on the movement amount using information about the installation position of the sensor 1350 and the installation position of the antenna 1340 and sets a compensation value. Accordingly, the terminal can compensate for a sensor value measured by the sensor 1350 or a new direction coordinate determined from the sensor value based on the compensation value and then use it as a value of the antenna.

[0184] The method according to the embodiments described in the claims or the specification of the disclosure can be implemented in hardware, software, or a combination of hardware and software.

[0185] For a software implementation, a computer-readable storage medium storing one or more programs (software modules) can be provided. The one or more programs stored in the computer-readable storage medium can be configured to be executed by one or more processors of an electronic device. The one or more programs can include instructions for enabling the electronic device to perform the methods according to the embodiments described in the claims or the specification of the disclosure.

[0186] Such programs (software modules, software) can be stored in random access memory, non-volatile memory including flash memory, read-only memory (ROM), electrically erasable ROM (EEPROM), magnetic disc storage device, compact disc (CD)-ROM, digital versatile disc (DVD), or other optical storage device, and cassette. Alternatively, the programs can be stored in a memory that combines some or all of the programs. In addition, a plurality of memories can be included.

[0187] In addition, the programs can be stored in a storage device that can be connected, which can be accessed through a communication network such as the Internet, an intranet, a local area network (LAN), a wide area network (WLAN), or a storage area network (SAN), or a communication network combining these networks. Such a storage device can be accessed by an external port to implement the device of the present disclosure. In addition, a separate storage device on a communication network can access the device implementing the embodiments of the present disclosure.

[0188] In specific embodiments of the disclosure as described above, the elements included in the disclosure are expressed in singular or plural. However, for ease of explanation, the singular or plural expression is appropriately selected according to the presented case, and the disclosure is not limited to a single element or multiple elements, and an element expressed in plural can be configured as a single element, and an element expressed in singular can be configured as multiple elements.

[0189] Meanwhile, the detailed description of the disclosure has been described with reference to some embodiments of the disclosure, but various modifications can be made without departing from the scope of the disclosure. Therefore, the scope of the disclosure should not be limited to the described embodiments, but should be defined by the appended claims and equivalents thereof within the scope of claims.

Claims

1. A method performed by a terminal in a wireless communication system, the method comprising: During the duration of the discontinuous operation mode, the receiving circuit is activated to receive signals; Identify whether the hibernation duration has been reached; In response to recognizing that the sleep duration has been reached, the receiving circuit is deactivated; During the first cycle of the sleep duration, multiple first reference signals are received; During the second cycle of the sleep duration, multiple second reference signals are received; The difference is identified based on the first set of measurement values ​​of the plurality of first reference signals and the second set of measurement values ​​of the plurality of second reference signals; After the first portion of the sleep duration has elapsed, if the difference is greater than a first threshold and the measurement pattern change counter is greater than a second threshold, beam misalignment is identified, wherein the measurement pattern change counter increases when the measurement order of the first measurement group and the measurement order of the second measurement group are different; and In response to the detection that the beam is misaligned, the receiving circuit is activated during the second part of the sleep duration to restore the beam.

2. The method according to claim 1, further comprising: In response to the beam not being misaligned, the receiving circuit is deactivated in the second part.

3. The method according to claim 1, wherein, The second part has the length of time required to perform the process for recovering the beam.

4. The method according to claim 1, wherein, The first set of measurements and the second set of measurements include two or more measurements from at least one beam.

5. The method according to claim 1, wherein, Identifying the beam misalignment includes: Compare the first style information and the second style information; and If the similarity between the first style information and the second style information is less than a third threshold, then the beam misalignment is identified. The first style information is defined based on at least one of the relative amplitude relationship of the first set of measurements or the measurement order sorted in ascending or descending order of the first set of measurements. The second style information is defined based on at least one of the relative amplitude relationship of the second group of measurements or the order of measurements sorted in ascending or descending order of the second group of measurements.

6. The method according to claim 5, wherein, The order of the measurements is determined such that beams corresponding to measurements with differences below the fourth threshold have the same level.

7. The method according to claim 5, further comprising: In response to the detection that the beam is misaligned, a message is sent to the base station requesting the transmission of a reference signal dedicated to the terminal; as well as The new serving beam is determined using the reference signal dedicated to the terminal.

8. The method according to claim 1, further comprising: In response to identifying the beam misalignment, a previous measurement value with pattern information similar to the second pattern information of the second measurement value group is identified; as well as The serving beam determined when the previous measurement value was obtained will be identified as the new serving beam.

9. The method according to claim 1, further comprising: In response to the detection of beam misalignment, a new serving beam is determined based on the directional coordinates of the main gain of the current serving beam and the amount of rotation or repositioning measured by at least one sensor.

10. A terminal in a wireless communication system, comprising: At least one transceiver; as well as A controller, connected to the at least one transceiver, and configured to perform the method according to any one of claims 1 to 9.

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