Efficient downlink data scheduling and ACK / NACK within frequency dependent multiple beams

Abstract

Methods and apparatus are provided for efficient downlink data scheduling and acknowledgement (ACK) / negative acknowledgement (NACK) within frequency dependent multiple beams. In a case where a plurality of user equipments (UEs) are respectively associated with a plurality of beams, a base station transmits reference signals to the plurality of UEs and receives measurement reports from the plurality of UEs. The measurement report includes information about the location and / or movement of each of the plurality of UEs. A base station determines a group including at least one UE based on measurement reports received from a plurality of UEs. In addition, the base station transmits second control information scheduling downlink data to the at least one UE belonging to the group, transmits the downlink data to the at least one UE, and receives a Hybrid Automatic Repeat Request (HARQ) transmission for the downlink data from the at least one UE.

Description

Technical Field

[0001] The present disclosure relates to efficient downlink data scheduling and acknowledgement (ACK) / negative acknowledgement (NACK) within frequency-correlated multi-beams. Background Art

[0002] The Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) is a technology for implementing high-speed packet communications. Many proposals have been made for LTE, including those aimed at reducing user and provider costs, improving quality of service, and expanding and improving coverage and system capacity. 3GPP LTE requires reduced cost per bit, increased service availability, flexible use of frequency bands, a simple architecture, open interfaces, and appropriate terminal power consumption as high-level requirements.

[0003] The International Telecommunication Union (ITU) and 3GPP have begun work to develop requirements and specifications for New Radio (NR) systems. 3GPP must identify and develop the technical components needed to successfully standardize a new RAT that meets both urgent market needs and the longer-term requirements set forth by the ITU Radiocommunication Sector (ITU-R) International Mobile Telecommunications (IMT)-2020 process. Furthermore, even in the more distant future, NR should be able to use any spectrum band available for wireless communication, at least up to 100 GHz.

[0004] NR aims for a single technology framework that addresses all use cases, requirements, and deployment scenarios, including enhanced mobile broadband (eMBB), massive machine-type communications (mMTC), ultra-reliable low-latency communications (URLLC), etc. NR should be inherently forward-compatible.

[0005] With the commercialization of NR, which corresponds to the fifth generation (5G) mobile communication technology, research on the sixth generation (6G) mobile communication technology has begun. 6G mobile communication technology is expected to utilize frequency bands of 100 GHz or higher. Therefore, compared with 5G, the utilization frequency can be increased by more than 10 times, and the potential for utilization of space resources is expected to increase further. This frequency band of 100 GHz or higher can be called sub-terahertz (sub-THz).

[0006] In the THz frequency band, assuming pencil beams, one user equipment (UE) can connect to each beam and transmit and receive data using a single carrier in a time division duplex (TDD) manner. Furthermore, in situations where low-end UEs transmitting and receiving low-capacity data coexist with high-end UEs transmitting and receiving high-capacity data, the current hybrid automatic repeat request (HARQ) process is performed regardless of the UE's capabilities. As the number of UEs increases, transmitting and receiving data and acknowledgement / negative acknowledgement (ACK / NACK) on a single carrier using pencil beams can result in longer delays. Summary of the Invention

[0007] Technical Solution

[0008] In one aspect, a method performed by a base station adapted to operate in a wireless communication system is provided. The method comprises the following steps: transmitting a reference signal to a plurality of user equipments (UEs) in a case where the plurality of UEs are respectively associated with a plurality of beams, and receiving measurement reports from the plurality of UEs. The measurement reports include information related to the location and / or movement of each of the plurality of UEs. The method comprises the following steps: determining a group including at least one UE based on the measurement reports received from the plurality of UEs. The method comprises the following steps: transmitting second control information for scheduling downlink data to at least one UE belonging to the group; transmitting downlink data to the at least one UE; and receiving a hybrid automatic repeat request (HARQ) transmission for the downlink data from the at least one UE.

[0009] In another aspect, a device for implementing the above method is provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 An example of a communication system to which an implementation of the present disclosure is applied is shown.

[0011] Figure 2 An example of a wireless device to which an implementation of the present disclosure is applied is shown.

[0012] Figure 3 An example of a wireless device to which an implementation of the present disclosure is applied is shown.

[0013] Figure 4 An example of a UE to which an implementation of the present disclosure is applied is shown.

[0014] Figure 5 An example of reception beam gain when Fc=10 GHz, the UE's beam reception angle is 20 degrees, and the base station transmits signals at a frequency of 9 GHz to 11 GHz at an angle of 0 to 40 degrees is shown.

[0015] Figure 6 Another example of reception beam gain is shown when Fc=10 GHz, the UE's beam reception angle is 20 degrees, and the base station transmits signals at a frequency of 9 GHz to 11 GHz at an angle of 0 to 40 degrees.

[0016] Figure 7 An example of a front-end antenna of a base station to which an implementation of the present disclosure is applied is shown.

[0017] Figure 8 An example of the difference between multi-beam and single beam applying the implementation of the present disclosure is shown.

[0018] Figure 9 An example of a method performed by a UE to which an implementation of the present disclosure is applied is shown.

[0019] Figure 10 An example of a method performed by a base station to which an implementation of the present disclosure is applied is shown.

[0020] Figure 11 An example of a method for turning on / off a multi-beam operation according to implementation manner 1 of the present disclosure is shown.

[0021] Figure 12 An example of a method for performing HARQ transmission by grouping UEs according to implementation mode 2 of the present disclosure is shown.

[0022] Figure 13 An example of a method for configuring a virtual UE according to implementation manner 3 of the present disclosure is shown.

[0023] Figure 14 An example of a layer grouping method according to implementation mode 4 of the present disclosure is shown.

[0024] Figure 15 An example of ACK / NACK transmission according to DL data transmission and UE grouping to which an implementation of the present disclosure is applied is shown. DETAILED DESCRIPTION

[0025] The following techniques, devices, and systems can be applied to various wireless multiple access systems. Examples of these multiple access systems include code division multiple access (CDMA) systems, frequency division multiple access (FDMA) systems, time division multiple access (TDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single carrier frequency division multiple access (SC-FDMA) systems, and multi-carrier frequency division multiple access (MC-FDMA) systems. CDMA can be implemented using radio technologies such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA can be implemented using radio technologies such as Global System for Mobile Communications (GSM), General Packet Radio Service (GPRS), or Enhanced Data Rates for GSM Evolution (EDGE). OFDMA can be implemented using radio technologies such as Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, or Evolved UTRA (E-UTRA). UTRA is part of Universal Mobile Telecommunications System (UMTS). 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) is part of Evolved UMTS (E-UMTS) that uses E-UTRA. 3GPP LTE uses OFDMA in the downlink (DL) and SC-FDMA in the uplink (UL). Evolutions of 3GPP LTE include LTE-Advanced (LTE-A), LTE-A Pro, and / or 5G New Radio (NR).

[0026] For ease of description, the embodiments of the present disclosure are primarily described with respect to a 3GPP-based wireless communication system. However, the technical features of the present disclosure are not limited thereto. For example, although the following detailed description is given based on a mobile communication system corresponding to a 3GPP-based wireless communication system, aspects of the present disclosure that are not limited to 3GPP-based wireless communication systems are applicable to other mobile communication systems.

[0027] For terms and techniques not specifically described in the terms and techniques adopted in the present disclosure, reference may be made to wireless communication standard documents issued prior to the present disclosure.

[0028] In the present disclosure, "A or B" may mean "only A", "only B", or "both A and B". In other words, in the present disclosure, "A or B" may be interpreted as "A and / or B". For example, in the present disclosure, "A, B, or C" may mean "only A", "only B", "only C", or "any combination of A, B, and C".

[0029] In the present disclosure, a slash ( / ) or a comma (,) may mean "and / or". For example, "A / B" may mean "A and / or B". Thus, "A / B" may mean "only A", "only B", or "both A and B". For example, "A, B, C" may mean "A, B, or C".

[0030] In the present disclosure, “at least one of A and B” may mean “only A”, “only B”, or “both A and B”. In addition, the expression “at least one of A or B” or “at least one of A and / or B” in the present disclosure may be interpreted as being the same as “at least one of A and B”.

[0031] In addition, in the present disclosure, “at least one of A, B, and C” may mean “only A,” “only B,” “only C,” or “any combination of A, B, and C.” In addition, “at least one of A, B, or C” or “at least one of A, B, and / or C” may mean “at least one of A, B, and C.”

[0032] In addition, the brackets used in the present disclosure may mean "for example". In detail, when "control information (PDCCH)" is shown, "PDCCH" may be proposed as an example of "control information". In other words, in the present disclosure, "control information" is not limited to "PDCCH", and "PDDCH" may be proposed as an example of "control information". In addition, even when "control information (i.e., PDCCH)" is shown, "PDCCH" may be proposed as an example of "control information".

[0033] The technical features described separately in one figure in this disclosure can be implemented separately or simultaneously.

[0034] Although not limited thereto, the various descriptions, functions, processes, suggestions, methods and / or operational flowcharts of the present disclosure disclosed herein may be applied to various fields requiring wireless communication and / or connectivity between devices (e.g., 5G).

[0035] Hereinafter, the present disclosure will be described in more detail with reference to the accompanying drawings. Unless otherwise specified, the same reference numerals in the following drawings and / or descriptions may refer to the same and / or corresponding hardware blocks, software blocks and / or functional blocks.

[0036] Figure 1 An example of a communication system to which an embodiment of the present disclosure is applied is shown.

[0037] exist Figure 1 The 5G usage scenarios shown in the present disclosure are only exemplary, and the technical features of the present disclosure can be applied to Figure 1 Other 5G usage scenarios shown in .

[0038] The three main demand categories for 5G include: (1) enhanced mobile broadband (eMBB) category, (2) massive machine type communication (mMTC) category, and (3) ultra-reliable and low-latency communication (URLLC) category.

[0039] Reference Figure 1 , the communication system 1 includes wireless devices 100a to 100f, a base station (BS) 200, and a network 300. Figure 1 A 5G network is illustrated as an example of the network of the communication system 1 , but the embodiments of the present disclosure are not limited to the 5G system and may be applied to future communication systems other than the 5G system.

[0040] BS 200 and network 300 may be implemented as wireless devices, and certain wireless devices may operate as BSs / network nodes relative to other wireless devices.

[0041] Wireless devices 100a to 100f represent devices that perform communication using a radio access technology (RAT) (e.g., 5G NR or LTE) and may be referred to as communication / wireless / 5G devices. Wireless devices 100a to 100f may include, but are not limited to, a robot 100a, vehicles 100b-1 and 100b-2, an extended reality (XR) device 100c, a handheld device 100d, a home appliance 100e, an Internet of Things (IoT) device 100f, and an artificial intelligence (AI) device / server 400. For example, a vehicle may include a vehicle with wireless communication capabilities, an autonomous vehicle, and a vehicle capable of performing communication between vehicles. A vehicle may include an unmanned aerial vehicle (UAV) (e.g., a drone). XR devices may include augmented reality (AR) / virtual reality (VR) / mixed reality (MR) devices and may be implemented in the form of a head-mounted device (HMD), a head-up display (HUD) installed in a vehicle, a television, a smartphone, a computer, a wearable device, a home appliance device, a digital signage, a vehicle, a robot, and the like. Handheld devices can include smartphones, smart tablets, wearable devices (e.g., smart watches or smart glasses), and computers (e.g., laptops). Home appliances can include TVs, refrigerators, and washing machines. IoT devices can include sensors and smart meters.

[0042] In the present disclosure, wireless devices 100a to 100f may be referred to as user equipment (UE). For example, UE may include a cellular phone, a smartphone, a laptop computer, a digital broadcast terminal, a personal digital assistant (PDA), a portable multimedia player (PMP), a navigation system, a tablet-shaped personal computer (PC), a tablet PC, an ultrabook, a vehicle, a vehicle with an autonomous driving function, a connected car, an UAV, an AI module, a robot, an AR device, a VR device, an MR device, a hologram device, a public safety device, an MTC device, an IoT device, a medical device, a Fintech device (or a financial device), a security device, a weather / environmental device, a device related to 5G services, or a device related to the field of the Fourth Industrial Revolution.

[0043] A UAV may be, for example, an aerial vehicle that is piloted by wireless control signals without a human on board.

[0044] VR devices may include, for example, devices for realizing objects or backgrounds in a virtual world. AR devices may include, for example, devices for realizing this by connecting objects or backgrounds in a virtual world to objects or backgrounds in the real world. MR devices may include, for example, devices for realizing this by merging objects or backgrounds in a virtual world into objects or backgrounds in the real world. Hologram devices may include, for example, devices for realizing 360-degree stereoscopic images by recording and reproducing stereoscopic information using a light interference phenomenon generated when two lasers meet, called a hologram.

[0045] Public safety devices may include, for example, image relay devices or image devices wearable on the user's body.

[0046] MTC devices and IoT devices may be devices that do not require direct human intervention or manipulation. For example, MTC devices and IoT devices may include smart meters, vending machines, thermometers, smart light bulbs, door locks, or various sensors.

[0047] A medical device may be, for example, a device for diagnosing, treating, alleviating, curing, or preventing a disease. For example, a medical device may be a device for diagnosing, treating, alleviating, or correcting an injury or damage. For example, a medical device may be a device for inspecting, replacing, or modifying a structure or function. For example, a medical device may be a device for regulating pregnancy. For example, a medical device may include a device for treatment, a device for operation, a device for (in vitro) diagnosis, a hearing aid, or a device for surgery.

[0048] The safety device may be, for example, a device installed to prevent possible danger and maintain safety. For example, the safety device may be a camera, a closed-circuit television (CCTV), a recorder, or a black box.

[0049] FinTech devices may be, for example, devices that can provide financial services such as mobile payments. For example, FinTech devices may include payment devices or point-of-sale (PoS) systems.

[0050] Weather / environmental devices may include, for example, devices for monitoring or predicting weather / environmental conditions.

[0051] Wireless devices 100a to 100f can connect to network 300 via BS 200. AI technology can be applied to wireless devices 100a to 100f, and wireless devices 100a to 100f can connect to AI server 400 via network 300. Network 300 can be configured using 3G networks, 4G (e.g., LTE) networks, 5G (e.g., NR) networks, and beyond 5G networks. Although wireless devices 100a to 100f can communicate with each other via BS 200 / network 300, wireless devices 100a to 100f can perform direct communication (e.g., sidelink communication) with each other without going through BS 200 / network 300. For example, vehicles 100b-1 and 100b-2 can perform direct communication (e.g., vehicle-to-vehicle (V2V) / vehicle-to-everything (V2X) communication). IoT devices (e.g., sensors) can perform direct communication with other IoT devices (e.g., sensors) or other wireless devices 100a to 100f.

[0052] Wireless communications / connections 150a, 150b, and 150c may be established between wireless devices 100a to 100f and / or between wireless devices 100a to 100f and BS 200 and / or between BS 200. Here, wireless communications / connections may be established via various RATs (e.g., 5G NR), such as uplink / downlink communication 150a, sidelink communication (or device-to-device (D2D) communication) 150b, and inter-base station communication 150c (e.g., relay, integrated access and backhaul (IAB)). Wireless devices 100a to 100f and BS 200 / wireless devices 100a to 100f may transmit / receive radio signals to / from each other via wireless communications / connections 150a, 150b, and 150c. For example, wireless communications / connections 150a, 150b, and 150c may transmit / receive signals via various physical channels. To this end, various configuration information configuration processes for sending / receiving radio signals, various signal processing processes (e.g., channel coding / decoding, modulation / demodulation, and resource mapping / demapping), and at least a portion of the resource allocation process can be performed based on the various proposals of the present disclosure.

[0053] AI refers to the field that studies artificial intelligence or methods that can create artificial intelligence, while machine learning refers to the field that defines the various problems solved in the field of AI and the methods for solving these problems. Machine learning is also defined as algorithms that improve the performance of tasks through consistent experience with the tasks.

[0054] A robot is a machine that automatically processes or operates a given task through its own capabilities. Specifically, a robot that has the ability to recognize its environment and self-determine to perform actions can be called an intelligent robot. Robots can be classified into industrial, medical, domestic, military, etc. according to their purpose or field of use. Robots can perform various physical operations such as moving robot joints using actuators or motors. Mobile robots also include wheels, brakes, propellers, etc. located on the drive, allowing them to drive on the ground or fly in the air.

[0055] Autonomous driving refers to the technology of driving by oneself, and autonomous vehicles refer to vehicles that are driven without user control or with minimal user control. For example, autonomous driving can include lane keeping, automatic speed adjustment (e.g., adaptive cruise control), automatic driving along a set route, and automatic route setting when a destination is set. Vehicles include vehicles equipped with internal combustion engines, hybrid vehicles equipped with internal combustion engines and electric motors, and electric vehicles equipped with electric motors, and can include trains, motorcycles, etc. as well as cars. Autonomous vehicles can be regarded as robots with autonomous driving capabilities.

[0056] Extended reality is collectively referred to as VR, AR, and MR. VR technology only provides real-world objects and backgrounds through computer graphics (CG) images. AR technology provides virtual CG images on top of real-world object images. MR technology is a CG technology that combines and integrates virtual objects into the real world. MR technology is similar to AR technology in that they show real objects and virtual objects together. However, the difference is that in AR technology, virtual objects are used as a complementary form of real objects, while in MR technology, virtual objects and real objects are used as equal personalities.

[0057] NR supports multiple parameter sets (and / or multiple subcarrier spacing (SCS)) to support various 5G services. For example, if the SCS is 15kHz, it can support wide areas in traditional cellular bands, and if the SCS is 30kHz / 60kHz, it can support dense cities, lower latency and wider carrier bandwidth. If the SCS is 60kHz or higher, bandwidth greater than 24.25GHz can be supported to overcome phase noise.

[0058] The NR frequency band can be defined as two types of frequency ranges, namely, frequency range 1 (FR1) and frequency range 2 (FR2). The numerical values ​​of the frequency ranges can be changed. For example, the two types of frequency ranges (FR1 and FR2) can be shown in Table 1 below. For ease of explanation, in the frequency range used in the NR system, FR1 can mean "a range below 6 GHz" and FR2 can mean "a range above 6 GHz" and can be referred to as millimeter wave (mmW).

[0059] [Table 1]

[0060] Frequency range specification Corresponding frequency range Subcarrier spacing FR1 450MHz–6000MHz 15, 30, 60kHz FR2 24250MHz–52600MHz 60, 120, 240kHz

[0061] As mentioned above, the numerical value of the frequency range of the NR system can be changed. For example, FR1 may include 410 MHz to 7125 MHz as shown in Table 2 below. That is, FR1 may include a frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or above. For example, the frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or above included in FR1 may include an unlicensed frequency band. The unlicensed frequency band can be used for various purposes, for example, communication of vehicles (for example, autonomous driving).

[0062] [Table 2]

[0063] Frequency range specification Corresponding frequency range Subcarrier spacing FR1 410MHz–7125MHz 15, 30, 60kHz FR2 24250MHz–52600MHz 60, 120, 240kHz

[0064] Here, the radio communication technology implemented in the wireless device of the present disclosure may include narrowband IoT (NB-IoT) technology for low-power communication, as well as LTE, NR, and 6G. For example, NB-IoT technology may be an example of low-power wide area network (LPWAN) technology, may be implemented in specifications such as LTE Cat NB1 and / or LTE Cat NB2, and may not be limited to the names mentioned above. Additionally and / or alternatively, the radio communication technology implemented in the wireless device of the present disclosure may be based on LTE-M technology for communication. For example, LTE-M technology may be an example of LPWAN technology and is referred to by various names such as enhanced MTC (eMTC). For example, LTE-M technology may be implemented in at least one of various specifications such as 1) LTE Cat 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTE non-bandwidth limited (non-BL), 5) LTE-MTC, 6) LTE machine type communication, and / or 7) LTE M, and may not be limited to the names mentioned above. Additionally and / or alternatively, the radio communication technology implemented in the wireless device of the present disclosure may include at least one of ZigBee, Bluetooth, and / or LPWAN considering low-power communication, and may not be limited to the names mentioned above. For example, ZigBee technology can generate a personal area network (PAN) associated with low / low-power digital communication based on various specifications such as IEEE 802.15.4, and may be referred to by various names.

[0065] Figure 2 An example of a wireless device to which an implementation of the present disclosure is applied is shown.

[0066] Reference Figure 2 , the first wireless device 100 and the second wireless device 200 can transmit / receive radio signals to / from an external device through various RATs (eg, LTE and NR).

[0067] exist Figure 2 In the example, {the first wireless device 100 and the second wireless device 200} may correspond to Figure 1 At least one of {wireless devices 100a to 100f and BS200}, {wireless devices 100a to 100f and wireless devices 100a to 100f} and / or {BS200 and BS200}.

[0068] The first wireless device 100 may include at least one transceiver, such as transceiver 106 ; at least one processing chip, such as processing chip 101 ; and / or one or more antennas 108 .

[0069] The processing chip 101 may include at least one processor, such as the processor 102 , and at least one memory, such as the memory 104 . Figure 2 exemplarily shown in FIG. 1 , the memory 104 is included in the processing chip 101. Additionally and / or alternatively, the memory 104 may be placed outside the processing chip 101.

[0070] The processor 102 may control the memory 104 and / or the transceiver 106 and may be configured to implement the descriptions, functions, processes, suggestions, methods, and / or operational flow charts described in the present disclosure. For example, the processor 102 may process information in the memory 104 to generate first information / signals, and then transmit a radio signal including the first information / signals through the transceiver 106. The processor 102 may receive a radio signal including second information / signals through the transceiver 106 and then store information obtained by processing the second information / signals in the memory 104.

[0071] Memory 104 may be operatively connected to processor 102. Memory 104 may store various types of information and / or instructions. Memory 104 may store software code 105 that implements instructions that, when executed by processor 102, perform the descriptions, functions, procedures, suggestions, methods, and / or operational flow charts disclosed herein. For example, software code 105 may implement instructions that, when executed by processor 102, perform the descriptions, functions, procedures, suggestions, methods, and / or operational flow charts disclosed herein. For example, software code 105 may control processor 102 to execute one or more protocols. For example, software code 105 may control processor 102 to execute one or more layers of a radio interface protocol.

[0072] In this document, the processor 102 and the memory 104 may be part of a communication modem / circuit / chip designed to implement a RAT (e.g., LTE or NR). The transceiver 106 may be connected to the processor 102 and transmit and / or receive radio signals via one or more antennas 108. Each of the transceivers 106 may include a transmitter and / or a receiver. The transceiver 106 may be used interchangeably with a radio frequency (RF) unit. In this disclosure, the first wireless device 100 may represent a communication modem / circuit / chip.

[0073] The second wireless device 200 may include at least one transceiver, such as transceiver 206 ; at least one processing chip, such as processing chip 201 ; and / or one or more antennas 208 .

[0074] The processing chip 201 may include at least one processor, such as the processor 202 , and at least one memory, such as the memory 204 . Figure 22. It is exemplarily shown in FIG. 2 that the memory 204 is included in the processing chip 201. Additionally and / or alternatively, the memory 204 may be placed outside the processing chip 201.

[0075] The processor 202 may control the memory 204 and / or the transceiver 206 and may be configured to implement the descriptions, functions, processes, suggestions, methods, and / or operational flow charts described in the present disclosure. For example, the processor 202 may process the information in the memory 204 to generate third information / signals, and then transmit a radio signal including the third information / signals through the transceiver 206. The processor 202 may receive a radio signal including fourth information / signals through the transceiver 106, and then store information obtained by processing the fourth information / signals in the memory 204.

[0076] Memory 204 may be operably connected to processor 202. Memory 204 may store various types of information and / or instructions. Memory 204 may store software code 205 that implements instructions that, when executed by processor 202, perform the descriptions, functions, procedures, suggestions, methods, and / or operational flow charts disclosed herein. For example, software code 205 may implement instructions that, when executed by processor 202, perform the descriptions, functions, procedures, suggestions, methods, and / or operational flow charts disclosed herein. For example, software code 205 may control processor 202 to execute one or more protocols. For example, software code 205 may control processor 202 to execute one or more layers of a radio interface protocol.

[0077] In this document, the processor 202 and the memory 204 may be part of a communication modem / circuit / chip designed to implement a RAT (e.g., LTE or NR). The transceiver 206 may be connected to the processor 202 and transmit and / or receive radio signals via one or more antennas 208. Each of the transceivers 206 may include a transmitter and / or a receiver. The transceiver 206 may be used interchangeably with an RF unit. In this disclosure, the second wireless device 200 may represent a communication modem / circuit / chip.

[0078] In the following, the hardware elements of the wireless devices 100 and 200 will be described in more detail. One or more protocol layers may be implemented by, but are not limited to, one or more processors 102 and 202. For example, one or more processors 102 and 202 may implement one or more layers (e.g., functional layers such as a physical (PHY) layer, a medium access control (MAC) layer, a radio link control (RLC) layer, a packet data convergence protocol (PDCP) layer, a radio resource control (RRC) layer, and a service data adaptation protocol (SDAP) layer). One or more processors 102 and 202 may generate one or more protocol data units (PDUs) and / or one or more service data units (SDUs) according to the descriptions, functions, processes, suggestions, methods, and / or operational flowcharts disclosed in the present disclosure. One or more processors 102 and 202 may generate messages, control information, data, or information according to the descriptions, functions, processes, suggestions, methods, and / or operational flowcharts disclosed in the present disclosure. The one or more processors 102 and 202 may generate a signal (e.g., a baseband signal) including a PDU, SDU, message, control information, data, or information according to the description, functions, procedures, suggestions, methods, and / or operational flowcharts disclosed in the present disclosure and provide the generated signal to the one or more transceivers 106 and 206. The one or more processors 102 and 202 may receive a signal (e.g., a baseband signal) from the one or more transceivers 106 and 206 and obtain the PDU, SDU, message, control information, data, or information according to the description, functions, procedures, suggestions, methods, and / or operational flowcharts disclosed in the present disclosure.

[0079] One or more processors 102 and 202 may be referred to as controllers, microcontrollers, microprocessors, or microcomputers. One or more processors 102 and 202 may be implemented by hardware, firmware, software, or a combination thereof. As an example, one or more application-specific integrated circuits (ASICs), one or more digital signal processors (DSPs), one or more digital signal processing devices (DSPDs), one or more programmable logic devices (PLDs), or one or more field-programmable gate arrays (FPGAs) may be included in one or more processors 102 and 202. The descriptions, functions, processes, suggestions, methods, and / or operational flowcharts disclosed in this disclosure may be implemented using firmware or software, and the firmware or software may be configured to include modules, processes, or functions. Firmware or software configured to execute the descriptions, functions, processes, suggestions, methods, and / or operational flowcharts disclosed in this disclosure may be included in one or more processors 102 and 202, or stored in one or more memories 104 and 204, so as to be driven by one or more processors 102 and 202. The descriptions, functions, processes, suggestions, methods and / or operational flow charts disclosed in this disclosure may be implemented using firmware or software in the form of codes, commands and / or command sets.

[0080] One or more memories 104 and 204 can be connected to one or more processors 102 and 202 and store various types of data, signals, messages, information, programs, codes, instructions and / or commands. One or more memories 104 and 204 can be configured by read-only memory (ROM), random access memory (RAM), electrically erasable programmable ROM (EEPROM), flash memory, hard drive, registers, cache memory, computer-readable storage media and / or combinations thereof. One or more memories 104 and 204 can be located inside and / or outside of one or more processors 102 and 202. One or more memories 104 and 204 can be connected to one or more processors 102 and 202 via various technologies such as wired connection or wireless connection.

[0081] One or more transceivers 106 and 206 can transmit user data, control information, and / or radio signals / channels mentioned in the description, functions, processes, suggestions, methods, and / or operational flowcharts disclosed in this disclosure to one or more other devices. One or more transceivers 106 and 206 can receive user data, control information, and / or radio signals / channels mentioned in the description, functions, processes, suggestions, methods, and / or operational flowcharts disclosed in this disclosure from one or more other devices. For example, one or more transceivers 106 and 206 can be connected to one or more processors 102 and 202 and transmit and receive radio signals. For example, one or more processors 102 and 202 can perform control so that one or more transceivers 106 and 206 can transmit user data, control information, or radio signals to one or more other devices. One or more processors 102 and 202 can perform control so that one or more transceivers 106 and 206 can receive user data, control information, or radio signals from one or more other devices.

[0082] One or more transceivers 106 and 206 may be connected to one or more antennas 108 and 208, and one or more transceivers 106 and 206 may be configured to transmit and receive user data, control information, and / or radio signals / channels as described, described, performed, performed, suggested, or described, and / or described in the flowcharts of the present disclosure. In the present disclosure, one or more antennas 108 and 208 may be multiple physical antennas or multiple logical antennas (e.g., antenna ports).

[0083] The one or more transceivers 106 and 206 may convert received user data, control information, radio signals / channels, etc. from RF band signals into baseband signals so that the received user data, control information, radio signals / channels, etc. may be processed using the one or more processors 102 and 202. The one or more transceivers 106 and 206 may convert user data, control information, radio signals / channels, etc. processed using the one or more processors 102 and 202 from baseband signals into RF band signals. To this end, the one or more transceivers 106 and 206 may include (analog) oscillators and / or filters. For example, under the control of the one or more processors 102 and 202, the one or more transceivers 106 and 206 may up-convert an OFDM baseband signal into an OFDM signal through their (analog) oscillators and / or filters and transmit the up-converted OFDM signal at a carrier frequency. The one or more transceivers 106 and 206 may receive an OFDM signal at a carrier frequency and down-convert the OFDM signal to an OFDM baseband signal through their (analog) oscillators and / or filters under the control of the one or more processors 102 and 202 .

[0084] In implementations of the present disclosure, a UE can operate as a transmitting device in the UL and as a receiving device in the DL. In implementations of the present disclosure, a base station can operate as a receiving device in the UL and as a transmitting device in the DL. Hereinafter, for convenience of description, it is primarily assumed that the first wireless device 100 is a UE and the second wireless device 200 is a base station. For example, the processor 102 connected to, installed on, or activated in the first wireless device 100 can be configured to execute UE behavior according to implementations of the present disclosure or control the transceiver 106 to execute UE behavior according to implementations of the present disclosure. The processor 202 connected to, installed on, or activated in the second wireless device 200 can be configured to execute base station behavior according to implementations of the present disclosure or control the transceiver 206 to execute base station behavior according to implementations of the present disclosure.

[0085] In this disclosure, a BS is also referred to as a Node B (NB), an eNode B (eNB), or a gNB.

[0086] Figure 3 An example of a wireless device to which an implementation of the present disclosure is applied is shown.

[0087] The wireless device can be implemented in various forms depending on the use case / service (see Figure 1 ).

[0088] Reference Figure 3 , the wireless devices 100 and 200 may correspond to Figure 2 The wireless devices 100 and 200 may be configured by various elements, components, units / portions and / or modules. For example, each of the wireless devices 100 and 200 may include a communication unit 110, a control unit 120, a memory unit 130, and an additional component 140. The communication unit 110 may include a communication circuit 112 and a transceiver 114. For example, the communication circuit 112 may include Figure 2 One or more processors 102 and 202 and / or Figure 2 One or more memories 104 and 204. For example, the transceiver 114 may include Figure 2 One or more transceivers 106 and 206 and / or Figure 2The control unit 120 is electrically connected to the communication unit 110, the memory unit 130, and the additional components 140, and controls the overall operation of each of the wireless devices 100 and 200. For example, the control unit 120 can control the electrical / mechanical operation of each of the wireless devices 100 and 200 based on the program / code / command / information stored in the memory unit 130. The control unit 120 can transmit information stored in the memory unit 130 to the outside (e.g., other communication devices) via the communication unit 110 through a wireless / wired interface, or store information received from the outside (e.g., other communication devices) through the wireless / wired interface in the memory unit 130 via the communication unit 110.

[0089] The additional component 140 may be configured differently depending on the type of the wireless devices 100 and 200. For example, the additional component 140 may include at least one of a power unit / battery, an input / output (I / O) unit (e.g., an audio I / O port, a video I / O port), a driving unit, and a computing unit. The wireless devices 100 and 200 may be implemented in the following forms, but are not limited to: a robot ( Figure 1 100a), vehicles ( Figure 1 100b-1 and 100b-2), XR devices ( Figure 1 100c), handheld device ( Figure 1 100d), household appliances ( Figure 1 100e), IoT devices ( Figure 1 100f), digital broadcast terminal, hologram device, public safety device, MTC device, medical device, FinTech device (or financial device), security device, climate / environmental device, AI server / device ( Figure 1 400), BS( Figure 1 200), network nodes, etc. The wireless devices 100 and 200 can be used in mobile or fixed locations depending on the use case / service.

[0090] exist Figure 3In the wireless devices 100 and 200, the various elements, components, units / parts, and / or modules in their entirety may be connected to each other via a wired interface, or at least a portion thereof may be wirelessly connected via the communication unit 110. For example, in each of the wireless devices 100 and 200, the control unit 120 and the communication unit 110 may be wired, and the control unit 120 and the first unit (e.g., 130 and 140) may be wirelessly connected via the communication unit 110. Each element, component, unit / part, and / or module within the wireless devices 100 and 200 may also include one or more elements. For example, the control unit 120 may be configured by a collection of one or more processors. As an example, the control unit 120 may be configured by a group of a communication control processor, an application processor (AP), an electronic control unit (ECU), a central processing unit (CPU), a graphics processing unit (GPU), and a memory control processor. As another example, the memory unit 130 may be configured by RAM, dynamic RAM (DRAM), ROM, flash memory, volatile memory, non-volatile memory, and / or a combination thereof.

[0091] Figure 4 An example of a UE to which an implementation of the present disclosure is applied is shown.

[0092] Reference Figure 4 , UE 100 may correspond to Figure 2 The first wireless device 100 and / or Figure 3 The wireless device 100 or 200.

[0093] UE 100 includes a processor 102 , memory 104 , a transceiver 106 , one or more antennas 108 , a power management module 141 , a battery 142 , a display 143 , a keypad 144 , a subscriber identity module (SIM) card 145 , a speaker 146 , and a microphone 147 .

[0094] The processor 102 may be configured to implement the descriptions, functions, processes, suggestions, methods, and / or operational flowcharts disclosed in the present disclosure. The processor 102 may be configured to control one or more other components of the UE 100 to implement the descriptions, functions, processes, suggestions, methods, and / or operational flowcharts disclosed in the present disclosure. The layers of the radio interface protocol may be implemented in the processor 102. The processor 102 may include an ASIC, other chipsets, logic circuits, and / or data processing devices. The processor 102 may be an application processor. The processor 102 may include at least one of a DSP, a CPU, a GPU, and a modem (modulator and demodulator). Examples of the processor 102 may be found in SNAPDRAGON MANUFACTURED TM series processors, Manufactured by EXYNOS TM series processors, A series processors manufactured by HELIO manufactured TM series processors, ATOM manufactured TM series processors or corresponding next-generation processors.

[0095] The memory 104 is operably coupled to the processor 102 and stores a variety of information to operate the processor 102. The memory 104 may include ROM, RAM, flash memory, a memory card, a storage medium, and / or other storage devices. When the embodiment is implemented in software, the techniques described herein can be implemented with modules (e.g., processes, functions, etc.) that execute the descriptions, functions, processes, suggestions, methods, and / or operational flow charts disclosed in this disclosure. The modules can be stored in the memory 104 and executed by the processor 102. The memory 104 can be implemented within the processor 102 or external to the processor 102, in which case the memory 104 can be communicatively coupled to the processor 102 via various means known in the art.

[0096] The transceiver 106 is operatively coupled to the processor 102 and transmits and / or receives radio signals. The transceiver 106 includes a transmitter and a receiver. The transceiver 106 may include baseband circuitry for processing radio frequency signals. The transceiver 106 controls one or more antennas 108 to transmit and / or receive radio signals.

[0097] The power management module 141 manages the power of the processor 102 and / or the transceiver 106. The battery 142 provides power to the power management module 141.

[0098] The display 143 outputs a result processed by the processor 102. The keyboard 144 receives an input to be used by the processor 102. The keyboard 144 may be shown on the display 143.

[0099] The SIM card 145 is an integrated circuit designed to securely store an International Mobile Subscriber Identity (IMSI) number and its associated keys, which are used to identify and authenticate subscribers on mobile telephony devices such as mobile phones and computers. Contact information can also be stored on many SIM cards.

[0100] The speaker 146 outputs sound-related results processed by the processor 102. The microphone 147 receives sound-related input to be used by the processor 102.

[0101] THz wireless communication is wireless communication using THz waves with a frequency of approximately 0.1THz to 10THz. That is, THz wireless communication is wireless communication using very high carrier frequencies of 100GHz or higher. THz waves are located between radio frequency (RF) / millimeter wave (mmWave) and infrared bands. THz waves penetrate non-metallic / non-polarizable materials, are superior to visible light / infrared rays, and have a shorter wavelength than RF / millimeter waves, so they have high flatness and can be focused. In addition, since the photon energy of THz waves is only a few meV, they have the characteristic of being harmless to the human body. The frequency band expected to be used for THz wireless communication may be the D band (110GHz to 170GHz) or the H band (220GHz to 325GHz), where the propagation loss caused by molecular absorption in the air is very small. THz wireless communication can be applied to wireless cognition, sensing, imaging, wireless communication, and THz navigation. Standardization discussions for THz wireless communication are underway in the 3GPP and IEEE 802.15THz working groups.

[0102] In THz wireless communications, due to severe path loss, it is necessary to maximize beam gain. Beams with low beam gain (e.g., conventional wide beams) may not be suitable for THz wireless communications. To maximize beam gain, one approach is to integrate a large number of antennas into a small space. However, if this approach is used, the number of microcell devices and / or RF chains connected to the devices increases, which may increase complexity and power consumption. In addition, the beams with high beam gain used in THz wireless communications are so narrow that they are called pencil beams, and therefore can be difficult to steer the beam.

[0103] When using pencil beams for THz wireless communications, due to the very narrow beamwidth, data transmission and reception, transmission and reception of acknowledgments (ACKs) / negative acknowledgments (NACKs) for the corresponding data, and / or transmission and reception of data retransmissions can be performed on a 1:1 basis with the UEs associated with each pencil beam. For example, a base station can use a pencil beam to transmit downlink data in the form of a single carrier, a UE associated with the pencil beam can transmit ACKs / NACKs for the received data, and the base station can retransmit the downlink data.

[0104] Furthermore, in the case where low-end UEs transmitting and receiving low-capacity data and high-end UEs transmitting and receiving high-capacity data coexist, the current hybrid automatic repeat request (HARQ) process is performed regardless of the capabilities of the UEs. As described above, if data and / or ACK / NACK transmission and reception are performed on a 1:1 basis with the UEs associated with the pencil beams, a very long delay may occur if the channel environment is poor.

[0105] Therefore, the present disclosure proposes a method of performing retransmission according to multi-beam based layer grouping.

[0106] First, as a prerequisite for multi-beam operation, beam deflection in an ultra-wideband environment will be described.

[0107] In THz wireless communications, beam skew may occur even when operating a single beam in a UWB environment, so it is necessary to minimize beam skew by utilizing true time delay (TTD). In the present disclosure, operating a single beam may mean minimizing beam skew by fixing Δτ, and in the case of beam scanning, varying Δτ according to the beam scanning angle or performing beam scanning using a phased antenna array (PAA).

[0108] The multi-beam can be formed into various shapes according to Δτ and Fm. In this disclosure, it is assumed that the base station has fixed Fm and reflects the fixed Δτ according to the angle to be covered by Fm. Therefore, Fm and Δτ do not change.

[0109] In wireless communications in environments with severe path loss (e.g., THz bands), configuring a transceiver with a large number of antenna elements to maximize beam gain is considered a method to overcome path loss. Furthermore, to transmit large amounts of data, methods are being considered to significantly widen the frequency band. However, the large number of antennas and the UWB environment significantly reduce the beam width. Consequently, the beam search process performed by the UE to align with the base station's beam can become very complex.

[0110] When aligned with the beam, the beam is aligned based on the center frequency, and the receiver can receive data through the beam. Since the bandwidth used in NR is a relatively narrow bandwidth ranging from 20 MHz to 100 MHz, there is no significant problem with beam alignment. However, since the bandwidth used in THz wireless communication is at least as wide as 1 GHz, the frequency offset becomes wider when the beam is aligned. In such an environment, it is difficult to meet frequency coherence, and the selectivity characteristics become very strong. As the frequency band increases, this phenomenon may be more serious, and this may lead to a problem in which the beam gain changes depending on the angle when the beam angle is considered. This problem is called beam deflection. Beam deflection also occurs in narrowband, but the degree is negligible. However, in wideband or ultra-wideband, the magnitude of beam gain loss may increase.

[0111] Equation 1 is an equation for calculating a beam gain according to an offset between a center frequency Fc set by a UE and a frequency position Fm of a signal transmitted by a base station.

[0112] [Formula 1]

[0113]

[0114] In Equation 1, θ0 is the reception angle of Fm, λ0 is the wavelength of Fm, θ is the reception angle of Fc, and λ is the wavelength of Fc. N is the number of antennas.

[0115] Figure 5 An example of reception beam gain when Fc=10 GHz, the UE's beam reception angle is 20 degrees, and the base station transmits signals at a frequency of 9 GHz to 11 GHz at an angle of 0 to 40 degrees is shown.

[0116] Reference Figure 5 , it can be confirmed that beam deflection occurs, where the beam gain changes by angle depending on the transmission frequency.

[0117] To eliminate this beam skew, a method of controlling the phase by adjusting the signal transmission delay between antennas using TTD elements instead of phased array elements in analog beamforming can be considered.

[0118] Figure 6 Another example of reception beam gain is shown when Fc=10 GHz, the UE's beam reception angle is 20 degrees, and the base station transmits signals at a frequency of 9 GHz to 11 GHz at an angle of 0 to 40 degrees.

[0119] Reference Figure 6 , it can be confirmed that beam deflection is eliminated by adjusting the signal transmission delay using TTD elements instead of phased array elements and adjusting the wavelength from Fm to Fc.

[0120] Such beam deflection can be used to form multiple beams. TTD-based multi-beam is a technology that uses the characteristic of changing the beam angle according to the length of the time delay, and is a technology that forms multiple beams with different angles for each frequency by generating a time delay difference between array antennas.

[0121] Equation 2 is an equation for calculating beam gain (or array gain) for frequency Fm when a time delay is applied to a uniformly spaced linear array.

[0122] [Formula 2]

[0123]

[0124] In Equation 2, Fc is the center frequency, and Fm is the frequency corresponding to subcarrier index m. Δτ is the time delay difference between array antenna elements. For example, based on the first array antenna element, the delay with the second array antenna element can be Δτ, and the delay with the third array antenna element can be Δτ*2.

[0125] When multi-beams are formed in this manner, the shapes of the multi-beams can also change as various conditions (eg, the number of subcarriers, the number of antennas, time delay difference) change.

[0126] When using multi-beams from a communication perspective, if the number of beams is N, resources up to bandwidth part (BWP) / N can be used for each beam. In addition, since the frequency resources that can be used by a single beam are limited, PAA technology can be used together for broadband data communication. For example, by using multiple panels, the same time delay TTD can be used for each panel, and at the same time, multiple layers with different phase shifts can be formed.

[0127] Equation 3 represents the antenna weight vector (AWV) applied to each array element n for the k-th layer (ie, corresponding to the k-th panel) in the PAA.

[0128] [Formula 3]

[0129] [w PAA，k ] n =exp[j2π(n-1)k / K]

[0130] In Equation 3, K is the total number of layers. According to Equation 3, the beam rotates, and if this is extended to multiple layers, as many resources as the number of layers*bandwidth allocated to each beam can be used in one beam.

[0131] In addition, in the present disclosure, the front-end antenna of the base station needs to be configured to be able to turn on / off multi-beam and single beam. Various methods can be applied to this, but in the present disclosure, only analog beamforming is explained under the assumption that one RF chain is used.

[0132] It can be seen from the above formula 2 that the magnitude of the beam gain depends on the angle and frequency, and it can also be seen that the spacing of the beam can be adjusted by Δτ. Therefore, the frequency-dependent angle and Δτ can be used to appropriately adjust the beam gain, and Δτ can be set to an arbitrary fixed value at the base station. In addition, TTD elements are currently being studied and / or have been implemented in the form of an integrated waveguide grid (e.g., a Butler matrix). However, in this method, the delay cannot be increased linearly indefinitely. Therefore, in the present disclosure, it is assumed that the center frequency Fc and the frequency offset are fixed.

[0133] Therefore, when multi-beam is in on mode, since Fc, Fm, and Δτ are all fixed, the base station can always form the same type of multi-beam. In addition, in single-beam on mode (or multi-beam off mode), since Fc and Fm are fixed, the base station can change the angle of the beam by changing Δτ according to the angle of arrival (AoA) between UEs. For example, assuming that three multi-beams are formed at angles of 30 degrees, 40 degrees, and 50 degrees, respectively, the Δτ that allows the beam to be focused in the 30-degree direction is different from the Δτ that allows the beam to be focused in the 40-degree direction, so the base station should have at most three Δτ.

[0134] Figure 7 An example of a front-end antenna of a base station to which an implementation of the present disclosure is applied is shown.

[0135] Reference Figure 7 The baseband signal processing unit of the front-end antenna of the base station processes the beam signal. The baseband signal processing unit includes a TTD control unit. The TTD control unit can control the linear application of delay to each TTD element to form multiple beams and / or a single beam in the AoA direction to be transmitted by the UE.

[0136] Advantages and disadvantages of the above-described communication using multiple beams according to frequency are as follows.

[0137] (1) Advantages

[0138] -Because multiple beams can be operated, beam scanning is not required.

[0139] -Communication in UWB can be supported by programmable time delays.

[0140] - Compared with PAA, it has low hardware complexity and low power consumption.

[0141] -No need to consider interference between beams.

[0142] (2) Disadvantages

[0143] Because frequency and angle are related, a single beam cannot utilize the entire UWB, and the bandwidth available to each beam is limited to (total bandwidth) / (number of beams). Furthermore, due to interference between beams, each beam must clear adjacent frequency resources. Therefore, frequency efficiency is lower than that of a single beam.

[0144] Figure 8 An example of the difference between multi-beam and single beam applying the implementation of the present disclosure is shown.

[0145] Reference Figure 8, a single beam can use all frequency resources (e.g., carriers) in UWB. On the other hand, multi-beam has restrictions on the frequency resources that each beam can use in UWB. For example, beam 1 can use carriers 1-3, beam 2 can use carriers 5-7, and beam 3 can use carriers 9-11. In addition, carriers 4, 7, and 12 cannot be used by any beam to prevent interference between beams.

[0146] - The resolution of the delay can be adjusted depending on the chip. Therefore, the controllable phase can be limited.

[0147] Hereinafter, the method for performing retransmission based on multiple beams proposed in the present disclosure is described. According to an implementation of the present disclosure, a base station can predict the distance of the UE and manage multiple UEs by grouping multiple UEs with similar channel quality (i.e., capable of setting the same modulation and coding scheme (MCS)) through reference signal received power (RSRP). More specifically, the base station can determine how many UEs can be covered via multiple beams, and can use this to group at least one UE that can be covered via multiple beams. The base station can schedule at least one UE belonging to the group to quickly send ACK / NACK, and can also schedule retransmissions so that at least one UE belonging to the group can quickly receive retransmitted data.

[0148] In the following, this disclosure assumes the following:

[0149] The bandwidth is preset according to the beam direction. For example, if the base station operates 8 multi-beams in a bandwidth of 1 GHz, the bandwidth allocated to each beam is 125 MHz. Therefore, the base station can preset Fm = 8 and bandwidth = 125 MHz.

[0150] Δτ is fixed according to Fm. For example, when Fm=8, Δτ will be a fixed value so that when multi-beam is in on mode, 8 beams can be formed at uniform angles, and 8 Δτ can be set so that when multi-beam is in off mode, a single beam can be operated in 8 directions.

[0151] The following figures are created to explain specific embodiments of the present disclosure. The names of specific devices or specific signals / messages / fields shown in the figures are provided by way of example, and therefore the technical features of the present disclosure are not limited to the specific names used in the following figures.

[0152] Figure 9 An example of a method performed by a UE to which an implementation of the present disclosure is applied is shown.

[0153] At step S900 , the method includes performing an initial access to a cell by performing a cell search.

[0154] At step S910 , the method includes receiving first control information triggering a reference signal from a cell.

[0155] At step S920 , the method includes receiving a reference signal from a cell.

[0156] At step S930 , the method includes performing measurements based on a reference signal.

[0157] At step S940, the method includes sending a measurement report based on the measurement to the cell. The measurement report includes information related to the location and / or movement of the UE.

[0158] At step S950 , the method includes receiving second control information for scheduling downlink data from a cell.

[0159] At step S960 , the method includes receiving downlink data from a cell.

[0160] At step S970 , the method includes performing HARQ transmission for downlink data to the cell.

[0161] In some implementations, a UE may be associated with one beam among multiple beams.

[0162] In some implementations, the bandwidth corresponding to one beam may be a portion of the total bandwidth allocated based on the beam angle of the UE.

[0163] In some implementations, the reference signal may be an aperiodic channel state information reference signal (CSI-RS).

[0164] In some implementations, the reference signal may be triggered by a multi-beam reference signal triggering parameter in the first control information.

[0165] In some implementations, the movement-related information may include at least one of the direction or speed of the UE.

[0166] In some implementations, a UE may communicate with at least one of a mobile device other than the UE, a network, and / or an autonomous vehicle.

[0167] In addition, the above Figure 9 The method described in the UE perspective can be obtained by Figure 2 The first wireless device 100 shown, Figure 3 The wireless device 100 and / or Figure 4 The UE 100 shown is used for execution.

[0168] More specifically, the UE includes: at least one transceiver, at least one processor, and at least one memory, wherein the at least one memory is operatively connected to the at least one processor and stores instructions. Operations performed by the at least one processor based on the instructions are as follows.

[0169] The UE performs initial access to a cell by performing a cell search.

[0170] The UE receives first control information triggering a reference signal from a cell via at least one transceiver.

[0171] The UE receives a reference signal from a cell via at least one transceiver.

[0172] The UE performs measurement based on the reference signal via at least one transceiver.

[0173] The UE sends a measurement report based on the measurement to the cell via at least one transceiver. The measurement report includes information related to the location and / or movement of the UE.

[0174] The UE receives second control information for scheduling downlink data from the cell via at least one transceiver.

[0175] The UE receives downlink data from the cell via at least one transceiver.

[0176] The UE performs HARQ transmission for downlink data to a cell via at least one transceiver.

[0177] In some implementations, a UE may be associated with one beam among multiple beams.

[0178] In some implementations, the bandwidth corresponding to one beam may be a portion of the total bandwidth allocated based on the beam angle of the UE.

[0179] In some implementations, the reference signal may be an aperiodic CSI-RS.

[0180] In some implementations, the reference signal may be triggered by a multi-beam reference signal triggering parameter in the first control information.

[0181] In some implementations, the information about the movement may include at least one of the direction or speed of the UE.

[0182] In addition, the above Figure 9 The method described in the UE angle can be included by controlling Figure 2 The processor 102 in the first wireless device 100 shown in FIG. Figure 3 The communication unit 110 and / or the control unit 120 in the wireless device 100 shown in FIG. 1 and / or the control unit 120 are included in the wireless device 100 by controlling Figure 4 The processor 102 in the UE 100 shown in FIG.

[0183] More specifically, a processing device adapted to control a UE in a wireless communication system includes: at least one processor and at least one memory, the at least one memory being operatively connected to the at least one processor and storing instructions. The at least one processor is configured to: obtain first control information for triggering a reference signal; obtain the reference signal; perform measurements based on the reference signal; generate a measurement report based on the measurements, wherein the measurement report includes information related to the location and / or movement of the UE; obtain second control information for scheduling downlink data; obtain the downlink data; and generate an ACK / NACK for the downlink data.

[0184] In addition, Figure 9 The method described in the UE perspective can be stored in the Figure 2 1 and 2. The first wireless device 100 is executed by the software code 105 in the memory 104 shown in FIG.

[0185] The technical features of the present disclosure can be implemented directly in hardware, in software executed by a processor, or in a combination of the two. For example, a method performed by a wireless device in wireless communication can be implemented in hardware, software, firmware, or any combination thereof. For example, the software can reside in RAM, flash memory, ROM, EPROM, EEPROM, registers, a hard disk, a removable disk, a CD-ROM, or any other storage medium.

[0186] Some examples of storage media may be coupled to a processor so that the processor can read information from the storage media. Alternatively, the storage media may be integrated into the processor. The processor and storage media may reside in an ASIC. For other examples, the processor and storage media may reside as discrete components.

[0187] The computer-readable medium may include tangible and non-transitory computer-readable storage media.

[0188] For example, non-transitory computer-readable media may include RAM, such as synchronous DRAM (SDRAM), ROM, non-volatile RAM (NVRAM), EEPROM, flash memory, magnetic or optical data storage media, or any other medium that can be used to store instructions or data structures. Non-transitory computer-readable media may also include combinations of the foregoing.

[0189] Furthermore, the methods described herein may be implemented at least in part by a computer-readable communication medium that carries or communicates code in the form of instructions or data structures and that can be accessed, read, and / or executed by a computer.

[0190] According to some implementations of the present disclosure, a non-transitory computer-readable medium (CRM) stores a plurality of instructions.

[0191] More specifically, a non-transitory CRM stores instructions, which perform operations based on being executed by at least one processor, the operations including: obtaining first control information for triggering a reference signal; obtaining a reference signal; performing measurements based on the reference signal; generating a measurement report based on the measurements, wherein the measurement report includes information related to the location and / or movement of the UE; obtaining second control information for scheduling downlink data; obtaining downlink data; and generating ACK / NACK for the downlink data.

[0192] Figure 10 An example of a method performed by a base station to which an implementation of the present disclosure is applied is shown.

[0193] At step S1000, the method includes performing initial access with a plurality of UEs, wherein the plurality of UEs are respectively associated with a plurality of beams.

[0194] In step S1010 , the method includes sending first control information for triggering a reference signal to a plurality of UEs.

[0195] At step S1020 , the method includes sending a reference signal to a plurality of UEs.

[0196] At step S1030, the method includes receiving measurement reports from a plurality of UEs. The measurement reports include information related to the location and / or movement of each of the plurality of UEs.

[0197] At step S1040 , the method includes determining a group including at least one UE based on measurement reports received from a plurality of UEs.

[0198] At step S1050 , the method includes transmitting second control information for scheduling downlink data to at least one UE belonging to the group.

[0199] At step S1060 , the method includes sending downlink data to at least one UE.

[0200] At step S1070 , the method includes receiving a HARQ transmission for downlink data from at least one UE.

[0201] In some implementations, the method may further include determining whether the plurality of UEs can receive multi-beam services. Determining whether the plurality of UEs can receive multi-beam services may include determining whether the plurality of UEs are low-end UEs. Alternatively, determining whether the plurality of UEs can receive multi-beam services may include determining whether the size of the downlink data is large enough to be provided by the multi-beam service.

[0202] In some implementations, the at least one UE belonging to the group may include some of the plurality of UEs.

[0203] In some implementations, at least one UE belonging to the group may include a virtual UE that is not included in the plurality of UEs.

[0204] In addition, the above Figure 10 The base station angle method described in the above can be obtained by Figure 2 The second wireless device 200 and / or Figure 3 The wireless device 200 shown in FIG.

[0205] More specifically, the base station includes: at least one transceiver; at least one processor; and at least one memory, wherein the at least one memory is operatively connected to the at least one processor and stores instructions. Operations performed by the at least one processor based on the instructions are as follows.

[0206] The base station performs initial access with multiple UEs, and the multiple UEs are associated with multiple beams, respectively.

[0207] The base station sends first control information for triggering a reference signal to a plurality of UEs via at least one transceiver.

[0208] The base station transmits a reference signal to a plurality of UEs via at least one transceiver.

[0209] The base station receives measurement reports from a plurality of UEs via at least one transceiver. The measurement reports include information related to the location and / or movement of each of the plurality of UEs.

[0210] The base station determines a group including at least one UE based on measurement reports received from a plurality of UEs.

[0211] The base station transmits second control information for scheduling downlink data to at least one UE belonging to the group via the at least one transceiver.

[0212] The base station transmits downlink data to at least one UE via at least one transceiver.

[0213] The base station receives a HARQ transmission for downlink data from at least one UE via at least one transceiver.

[0214] In some implementations, a base station may determine whether multiple UEs can receive multi-beam services. Determining whether the multiple UEs can receive multi-beam services may include determining whether the multiple UEs are low-end UEs. Alternatively, determining whether the multiple UEs can receive multi-beam services may include determining whether the size of downlink data is large enough to be provided by the multi-beam service.

[0215] In some implementations, the at least one UE belonging to the group may include some of the plurality of UEs.

[0216] In some implementations, at least one UE belonging to the group may include a virtual UE that is not included in the plurality of UEs.

[0217] Hereinafter, various embodiments of the present disclosure will be described.

[0218] 1. Implementation 1: Method for turning multi-beam operation on / off

[0219] Figure 11 An example of a method for turning on / off a multi-beam operation according to implementation manner 1 of the present disclosure is shown.

[0220] In step S1100 , the base station checks whether there is a low-end UE.

[0221] If there is a low-end UE, the base station starts multi-beam operation in step S1102 to provide multi-beam service.

[0222] If there are no low-end UEs, the base station may essentially disable multi-beam operation. However, in step S1104, the base station may determine whether DL data can be provided to a specific number of UEs via multi-beam service. For example, the base station may determine whether the size of the DL data to be transmitted is a size that can be provided via multi-beam service. If the DL data can be provided via multi-beam service, the base station enables multi-beam operation according to step S1102. Otherwise, the base station disables multi-beam operation according to step S1106.

[0223] 2. Implementation 2: Method for performing HARQ transmission by grouping UEs

[0224] Figure 12 An example of a method for performing HARQ transmission by grouping UEs according to implementation mode 2 of the present disclosure is shown.

[0225] In step S1200 , the base station and a plurality of UEs are in a state where they can transmit and receive data, and the initial cell search process is completed.

[0226] First, according to the method for turning on / off multi-beam operation according to implementation mode 1 of the present disclosure described above, the base station can check whether the target UE to be transmitted is capable of receiving multi-beam service in order to transmit DL data. Figure 12 In the example, it is assumed that UE1, UE2, UE3 and UE4 can receive multi-beam services.

[0227] If the UE can receive multi-beam service (ie, multi-beam operation is on), then in step S1202, the base station triggers aperiodic CSI to the corresponding UE and sends the aperiodic CSI to the corresponding UE.

[0228] Aperiodic CSI may be triggered via a UL DCI format (e.g., UL DCI format 0_1). For example, UL DCI format 0_1 ​​may include a parameter for triggering multi-beam aperiodic CSI-RS. The parameter may indicate a beam ID corresponding to a beam in bits ranging from 0 to the maximum number of multi-beams. A value of 0 for the parameter may indicate that multi-beams are not used.

[0229] Since the CSI-RS associated with multi-beams will be measured by the UE in a narrowband, the base station can configure a resource list for multi-beams in the PDSCH-Config Information Element (IE) sent via an RRC message.

[0230] Table 3 shows an example of PDSCH-Config IE according to Implementation 2 of the present disclosure. Table 3 assumes that the maximum number of beams that the base station can operate is 8, but this may vary.

[0231] [Table 3]

[0232]

[0233] Comparing the parameters (or fields) for configuring MultiBeam_CSI_RS_Resource with the existing CSI-RS-ResourceMapping, since the channel is selective even within the bandwidth, the CSI can be widely distributed in the high-gain part of each beam, and the CSI can be densely arranged in the low-gain part. Therefore, in addition to frequencyDomainAllocation, MultiBeam_CSI_RS_Resource and CSI-RS-ResourceMapping can be different.

[0234] In step S1204, each UE receiving the CSI-RS measures the CSI-RS and reports the measurement result to the base station through a multi-beam measurement report.

[0235] In addition to previously reported information (e.g., RSRP, Channel Quality Indicator (CQI)), the UE may additionally report its own mobility information acquired through a global positioning system (GPS) or a device that can acquire information about the direction or speed of its movement. That is, the mobility information may include the UE's direction information (e.g., east, west, south, north) and / or speed information.

[0236] For example, the UE can know the bandwidth information associated with its beam through RRC configuration. For example, in UWB, the UE can identify the beam ID associated with itself through the identifier (ID) of the multi-beam, identify the starting resource block (RB) of the bandwidth associated with its beam through the value of Freq_start, and identify the last RB of the bandwidth associated with its beam through Freq_end. In addition, since the power gain is different within the bandwidth, RSRP and / or CQI can be measured in units of measurement length. Through the measurement results, the UE can know whether the channel environment is low and / or whether it is roughly located on the outer side of the beam coverage range. If the UE determines that it is on the outer side of the beam coverage range, it can report its mobility information to the base station by including its mobility information in the multi-beam measurement report.

[0237] In step S1206, the base station determines the group based on the multi-beam measurement report received from the UE. The base station can know the RSRP, CQI, mobility information, AoA, etc. of each UE based on the multi-beam measurement report and can use it for scheduling in various ways. This will be described below.

[0238] In step S1210, the base station sends DCI and DL data scheduled by the corresponding DCI to UE1, UE2 and UE4 grouped in the group. In addition, in step S1212, the base station sends another DCI and DL data scheduled by the corresponding DCI to UE3 not grouped in the group.

[0239] In step S1220, UE1, UE2, and UE4 grouped in the group perform HARQ transmission for received DL data to the base station. In addition, in step S1222, UE3 not grouped in the group also performs HARQ transmission for received DL data to the base station.

[0240] 3. Implementation 3: Base station scheduling UE based on multi-beam measurement reports

[0241] The base station can calculate an approximate signal-to-noise ratio (SNR) from the RSRP in the multi-beam measurement report reported by each UE. The base station can know in advance the amount of DL data to be sent to the UE and can use the SNR to determine the MCS for sending the corresponding DL data. The SNR increases as the power value carried on the carrier increases. The base station can increase the power per RB according to the number of beams forming the multi-beam. For example, assuming that the multi-beam can be formed with 8 beams, a power gain can occur because the power from the remaining 6 unused beams when only 2 beams are used can be collected and sent to the 2 beams used.

[0242] In addition, the base station can compensate for the SNR in the following manner through the mobility information in the multi-beam measurement report reported by each UE.

[0243] 1) If the base station can know that the UE is moving in the direction of an adjacent beam through the mobility information reported by the UE, the base station can send DCI for scheduling the UE to the adjacent beam. If the UE is fast, the base station can send DCI for scheduling the UE to multiple beams, not just adjacent beams. Since frequency and beam angle are dependent on each other, the base station only sends DCI to different carriers. The content included in the DCI can be different. However, the transport block size (TBS) is set to the same.

[0244] Figure 13 An example of a method for configuring a virtual UE according to implementation manner 3 of the present disclosure is shown.

[0245] Reference Figure 13 , if the base station can know that UE2 can move in the direction of an adjacent beam through the mobility information reported by UE2, the base station can configure a virtual UE (such as UE2-2) that does not actually exist in the adjacent beam and include UE2-2 in the target of the UE grouping.

[0246] Even if there is actually another UE in the adjacent beam, since the scrambling ID of the DCI is different, the other UE cannot decode the DCI. Only the UE moved to the beam can decode the DCI.

[0247] 2) In a line-of-sight (LoS) environment, if the distance from the base station remains almost the same even when UE2 moves to an adjacent beam, the base station may use the same measured RSRP and / or CQI. Alternatively, if the distance from the base station increases as UE2 moves to an adjacent beam, the base station may reduce the SNR in proportion to the increase in distance. Alternatively, if UE2 moves to an adjacent beam and becomes closer to the base station, the base station may increase the SNR in proportion to the closer distance.

[0248] 3) Assuming that the direction in which UE2 moves is within the synchronization signal block (SSB) to which the CSI belongs, a wide beam can be formed. The channel of the wide beam can use the value measured by the CSI.

[0249] 4. Implementation 4: Layer Grouping Method for DL ​​Data Transmission

[0250] Since the output power decreases according to the number of beams when forming multiple beams, the SNR decreases and the MCS index also decreases accordingly. Implementation 4 of the present disclosure discloses a method of performing layer grouping based on an MCS index determined by RSRP and / or CQI reported from a UE.

[0251] The base station can increase the power per RB based on the number of beams forming multi-beams. For example, if multi-beams can utilize 8 beams, power gain can occur because when only 2 beams are used, the power from the remaining 6 unused beams can be collected and sent to the 2 beams that use power. Therefore, layer grouping can be performed based on the MCS index and the number of multi-beams.

[0252] Figure 14 An example of a layer grouping method according to implementation mode 4 of the present disclosure is shown.

[0253] In step S1400, the base station sets the maximum number of multi-beams (MaxMultibeam). Figure 14 If there are 4 UEs that need to transmit simultaneously, the maximum number of beams that can be operated can be 4. In other words, the maximum number of beams that can be operated can be the same as the number of UEs that need to transmit simultaneously. Therefore, the base station sets MaxMultiBeam = 4. Alternatively, if the number of UEs that need to transmit simultaneously is greater than the maximum number of beams that can be operated, MaxMultiBeam can be set to the maximum number of beams that can be operated.

[0254] The base station may know the MCS index required for DL ​​data to be transmitted to each UE.

[0255] The base station performs grouping based on the RSRP reported from each UE. In step S1402, the base station determines whether data transmission and reception via the multi-beam service is possible based on the UE with the lowest RSRP. Specifically, since Figure 14 Since MaxMultiBeam=4 is set in

[14] , the base station infers the highest possible MCS when operating four beams based on the UE with the lowest RSRP. If the inferred MCS is lower than the UE's required MCS index, the UE is excluded, and the UE with the second lowest RSRP becomes the reference (step S1410). If the inferred MCS is higher than the UE's required MCS index (i.e., satisfies

[14] ), the base station groups the UE with a UE with a higher RSRP (step S1404).

[0256] If the number of UEs excluded in the grouping step is one or more (step S1406), the base station performs the next operation for the remaining UEs excluded from the group (step S1408). The base station determines whether the number of remaining UEs is greater than or equal to MaxMultibeam (step S1412), and if the number of remaining UEs is less than MaxMultibeam, sets MaxMultibeam to the number of remaining UEs (step S1416). For example, if Figure 14If the number of remaining UEs is 2, the base station changes MaxMultibeam to 2. If the number of remaining UEs is greater than or equal to MaxMultibeam, MaxMultibeam remains unchanged (step S1414).

[0257] Since the power per RB is increased when operating two beams, a relatively high MCS index can be set even when channel quality is low. When the increased power per RB is applied, the base station checks whether the MCS index can be met for the remaining two UEs. If the MCS index can be met, the base station groups the remaining two UEs.

[0258] According to the above-mentioned implementation mode 3 of the present disclosure, when setting a virtual UE in an adjacent beam, the following two operations can be considered.

[0259] - The virtual UE may be excluded from the group. The base station may transmit to the virtual UE using TDD based on a wide single beam.

[0260] The beams mapped to the virtual UE are physically different. Therefore, the channel quality may be different. For example, assuming that UE2 is in beam 3, the measurement report reported by UE2 is the measurement value for beam 3. Even if UE2 moves in the direction of beam 2 and beam 1, the base station cannot know the channel measurement values ​​for beam 2 and beam 1. Therefore, if there is a value previously measured and reported by another UE for the setup beam of the virtual UE, that value can be used; otherwise, the measurement value for beam 3 can be used.

[0261] The DCI content for each UE may be different.

[0262] According to implementation mode 4 of the present disclosure, grouping may have an advantage in terms of peak-to-average power ratio (PAPR).

[0263] Figure 15 An example of ACK / NACK transmission according to DL data transmission and UE grouping to which an implementation of the present disclosure is applied is shown.

[0264] Reference Figure 15 , the transmission groups for DL ​​data are divided into Group 1 including UE5, Group 2 including UE1 / UE7, and Group 3 including UE2 / UE3 / UE4 / UE6. The base station transmits DL data for each group. On the other hand, the ACK / NACK transmission groups are divided into Group 1 including UE1 / UE5 / UE7 and Group 2 including UE2 / UE3 / UE4 / UE6. In other words, UE5 belongs to the same Group 1 as UE1 / UE7 and transmits ACK / NACK. This is because UE5 is located in the same beam direction as UE1.

[0265] The present disclosure may have various beneficial effects.

[0266] For example, the base station may group at least one UE that can be covered by multiple beams into one group.

[0267] For example, the base station may schedule at least one UE belonging to the group to quickly send ACK / NACK.

[0268] For example, the base station may schedule retransmission so that at least one UE belonging to the group can quickly receive the retransmission data.

[0269] The beneficial effects obtained through the specific examples of this specification are not limited to the effects listed above. For example, there may be a variety of technical effects that a person of ordinary skill in the art can understand or derive from this specification. Therefore, the specific effects of the present disclosure are not limited to those explicitly described herein, but may include various effects that can be understood or derived from the technical features of the present disclosure.

[0270] The claims in this disclosure can be combined in various ways. For example, the technical features in the method claims of this disclosure can be combined to be implemented or performed in an apparatus, and the technical features in the apparatus claims can be combined to be implemented or performed in a method. Furthermore, the technical features in the method claims and the apparatus claims can be combined to be implemented or performed in an apparatus. Furthermore, the technical features in the method claims and the apparatus claims can be combined to be implemented or performed in a method. Other embodiments are within the scope of the appended claims.

Claims

1. A method performed by a user equipment (UE) adapted to operate in a wireless communication system, the method comprising the following steps: performing initial access to a cell by performing a cell search; receiving first control information triggering a reference signal from the cell; receiving the reference signal from the cell; performing measurements based on the reference signal; sending a measurement report based on the measurement to the cell, wherein the measurement report includes information related to the location and / or movement of the UE; receiving second control information for scheduling downlink data from the cell; receiving the downlink data from the cell; and A hybrid automatic repeat request (HARQ) transmission for the downlink data is performed to the cell.

2. The method according to claim 1, wherein The UE is associated with one beam among a plurality of beams.

3. The method according to claim 1, wherein The bandwidth corresponding to the one beam is a portion of a total bandwidth allocated based on the beam angle of the UE.

4. The method according to claim 1, wherein The reference signal is an aperiodic channel state information reference signal CSI-RS.

5. The method according to claim 1, wherein The reference signal is triggered by a multi-beam reference signal triggering parameter in the first control information.

6. The method according to claim 1, wherein The information related to the movement includes at least one of a direction or a speed of the UE.

7. The method according to claim 1, wherein The UE communicates with at least one of a mobile device, a network, and / or an autonomous vehicle other than the UE.

8. A user equipment (UE) adapted to operate in a wireless communication system, the UE comprising: at least one transceiver; at least one processor; as well as at least one memory operatively connected to the at least one processor and storing instructions that, upon execution by the at least one processor, perform operations comprising: performing initial access to a cell by performing a cell search; receiving, via the at least one transceiver, first control information triggering a reference signal from the cell; receiving the reference signal from the cell via the at least one transceiver; performing measurements based on the reference signal; sending, via the at least one transceiver, a measurement report based on the measurement to the cell, wherein the measurement report includes information related to the location and / or movement of the UE; receiving, via the at least one transceiver, second control information for scheduling downlink data from the cell; receiving the downlink data from the cell via the at least one transceiver; and A hybrid automatic repeat request (HARQ) transmission for the downlink data is performed to the cell via the at least one transceiver.

9. The UE according to claim 8, wherein: The UE is associated with one beam among a plurality of beams.

10. The UE according to claim 8, wherein: The bandwidth corresponding to the one beam is a portion of a total bandwidth allocated based on the beam angle of the UE.

11. The UE according to claim 8, wherein: The reference signal is an aperiodic channel state information reference signal CSI-RS.

12. The UE according to claim 8, wherein: The reference signal is triggered by a multi-beam reference signal triggering parameter in the first control information.

13. The UE according to claim 8, wherein: The information related to the movement includes at least one of a direction or a speed of the UE.

14. A processing device adapted to control a user equipment (UE) in a wireless communication system, the processing device comprising: at least one processor; as well as at least one memory operatively connectable to the at least one processor, The at least one processor is configured to perform operations, the operations comprising: Obtaining first control information of a trigger reference signal; obtaining the reference signal; performing measurements based on the reference signal; generating a measurement report based on the measurement, wherein the measurement report includes information related to the location and / or movement of the UE; obtaining second control information for scheduling downlink data; obtaining the downlink data; and An ACK / NACK for the downlink data is generated.

15. A non-transitory computer readable medium (CRM) storing instructions, wherein: The non-transitory CRM is configured to perform operations including: Obtaining first control information of a trigger reference signal; obtaining the reference signal; performing measurements based on the reference signal; generating a measurement report based on the measurement, wherein the measurement report includes information related to the location and / or movement of the UE; obtaining second control information for scheduling downlink data; obtaining the downlink data; and An ACK / NACK for the downlink data is generated.

16. A method performed by a base station adapted to operate in a wireless communication system, the method comprising the steps of: performing initial access with a plurality of UEs, wherein the plurality of UEs are respectively associated with a plurality of beams; Sending first control information triggering a reference signal to the multiple UEs; sending the reference signal to the multiple UEs; receiving measurement reports from the plurality of UEs, wherein the measurement reports include information related to a location and / or movement of each of the plurality of UEs; determining, based on the measurement reports received from the plurality of UEs, a group including at least one UE; sending second control information for scheduling downlink data to the at least one UE belonging to the group; sending the downlink data to the at least one UE; A hybrid automatic repeat request (HARQ) transmission for the downlink data is received from the at least one UE.

17. The method according to claim 16, further comprising the steps of: Determine whether the plurality of UEs are capable of receiving multi-beam services.

18. The method according to claim 17, wherein: The step of determining whether the plurality of UEs are capable of receiving the multi-beam service includes determining whether the plurality of UEs are low-end UEs.

19. The method according to claim 17, wherein The step of determining whether the plurality of UEs are capable of receiving the multi-beam service includes determining whether a size of the downlink data is large enough to be provided by the multi-beam service.

20. The method according to claim 16, wherein The at least one UE belonging to the group includes some UEs among the plurality of UEs.

21. The method according to claim 16, wherein The at least one UE belonging to the group includes a virtual UE that is not included in the plurality of UEs.

22. A base station adapted to operate in a wireless communication system, the base station comprising: at least one transceiver; at least one processor; as well as at least one memory operatively connected to the at least one processor and storing instructions that, upon execution by the at least one processor, perform operations comprising: performing initial access with a plurality of UEs, wherein the plurality of UEs are respectively associated with a plurality of beams; Sending first control information triggering a reference signal to the multiple UEs via the at least one transceiver; transmitting the reference signal to the plurality of UEs via the at least one transceiver; receiving, via the at least one transceiver, measurement reports from the plurality of UEs, wherein the measurement reports include information related to a location and / or movement of each of the plurality of UEs; determining, based on the measurement reports received from the plurality of UEs, a group including at least one UE; transmitting, via the at least one transceiver, second control information for scheduling downlink data to the at least one UE belonging to the group; transmitting the downlink data to the at least one UE via the at least one transceiver; A hybrid automatic repeat request (HARQ) transmission for the downlink data is received from the at least one UE via the at least one transceiver.

Images